CN118176072A

CN118176072A - Local pressurizing device, forming machine and forming method

Info

Publication number: CN118176072A
Application number: CN202280072675.XA
Authority: CN
Inventors: 吉田浩; 辻真; 野田三郎
Original assignee: Zhipu Machinery Co ltd
Current assignee: Zhipu Machinery Co ltd
Priority date: 2021-10-29
Filing date: 2022-10-28
Publication date: 2024-06-11
Also published as: WO2023074851A1; MX2024005011A; JP2023066640A

Abstract

The local pressurizing device (2) of the present invention comprises: a pressing member (41) having a tip exposed to a space (107) of the mold (101); and a driving unit (45) that applies a forward force to the pressing member (41). When the molten metal reaches the position of the pressurizing member (41), the pressurizing member (41) is positioned at an initial position in front of the retraction limit, and is pushed by the molten metal to retract from the initial position.

Description

Local pressurizing device, forming machine and forming method

Technical Field

The present invention relates to a local pressurizing device that locally pressurizes a molding material in a mold, a molding machine including the local pressurizing device, and a molding method that locally pressurizes the molding material. The molding machine is, for example, a die casting machine for molding metal or an injection molding machine for molding resin.

Background

In molding methods such as die casting, a technique of performing so-called partial pressurization is known (for example, patent documents 1 to 4 below). In this technique, a molding material is filled into the mold (a space formed by the mold, and the same applies hereinafter), and then the molding material is pressed by a pressing pin inserted into the mold. Thus, shrinkage cavities caused by solidification shrinkage of the molding material can be reduced, for example.

When the molding material is filled into the mold, the pressing pin stands by at the backward limit of its stroke (the drive limit on the opposite side from the interior of the mold). Thus, when the pressing pin is advanced to press the molding material after filling, the maximum value that can be obtained in the advance distance can be used as the stroke of the pressing pin. That is, the stroke of the pressing pin can be utilized to the maximum.

Prior art literature

Patent literature

Patent document 1: japanese patent laid-open No. 2008-142758

Patent document 2: japanese patent laid-open publication 2016-87638

Patent document 3: japanese patent laid-open publication No. 2005-334977

Patent document 4: japanese patent laid-open No. 4-94854

Problems to be solved by the invention

The manner in which the pressure pin is used can affect the quality of the formed material. For example, if the timing at which the pressing pin starts to advance is too early, plastic flow of the molding material does not occur, and a sufficient pressing effect cannot be obtained. If the timing of starting the advancement is later, the pressing pin is not pressed into a sufficient depth by solidification of the molding material, and a sufficient pressing effect is not obtained. Therefore, a local pressurizing device, a molding machine, and a molding method that can appropriately use a pressurizing member (pressurizing pin) are desired.

Disclosure of Invention

The local pressurizing device according to an embodiment of the present invention includes: a pressing member having a tip exposed to the inside of the mold; and a driving unit that applies a forward force to the pressing member. The pressing member is positioned at an initial position forward of a retraction limit when the molding material reaches the pressing member position, and is pushed by the molding material to retract from the initial position.

A molding machine (molding machine) according to an aspect of the present invention includes the above-described local pressurizing device, a mold clamping device for opening and closing the mold, and an injection device for injecting the molding material into the mold.

The molding method (molding method) according to an embodiment of the present invention includes: an injection step of injecting a molding material into the mold; and a partial pressurizing step of pressurizing the molding material in the mold by advancing a pressurizing member having a tip exposed to the inside of the mold. The pressing member is positioned at an initial position forward of a retraction limit when the molding material reaches the position of the pressing member, and is pushed by the molding material to retract from the initial position.

Effects of the invention

According to the above configuration or steps, the pressing member can be appropriately used by the retraction of the pressing member. For example, the pressing member is retracted, so that the impact pressure generated when the molding material is filled into the mold can be absorbed. Further, for example, the timing at which the pressing member starts to advance can be appropriately determined based on the detection of the arrival of the molding material at the pressing member.

Drawings

Fig. 1 (a) is a schematic diagram showing the operation of the local pressurizing device for explaining the gist of the local pressurizing device according to the embodiment, and fig. 1 (b) is a partial enlarged view of fig. 1 (a).

Fig. 2 (a) is a schematic diagram showing the operation subsequent to that of fig. 1 (a), and fig. 2 (b) is a partial enlarged view of fig. 2 (a).

Fig. 3 (a) is a schematic diagram showing the operation subsequent to that of fig. 2 (a), and fig. 3 (b) is a partial enlarged view of fig. 3 (a).

Fig. 4 is a side view showing a configuration of a main part of the die casting machine of the first embodiment.

Fig. 5 is a schematic view showing the structure of a pressurizing device of the die casting machine of fig. 4.

Fig. 6 is a circuit diagram showing the configuration of the hydraulic device included in the pressurizing device of fig. 5.

Fig. 7 is a diagram for explaining an operation of the die casting machine of fig. 4.

Fig. 8 is a flowchart showing a procedure of processing executed by the control device for realizing the operation in fig. 7.

Fig. 9 (a) and 9 (b) are cross-sectional views showing the structure of the pressurizing device according to the second embodiment.

Fig. 10 is a cross-sectional view showing the structure of a pressurizing device according to a third embodiment.

Fig. 11 is a cross-sectional view showing the structure of a pressurizing device according to the fourth embodiment.

Fig. 12 is a schematic view showing the structure of a die casting machine according to a fifth embodiment.

Fig. 13 is a cross-sectional view showing another example of the position of the pressing member.

Detailed Description

Embodiments of the present invention will be described below with reference to the drawings. In addition, only the differences from the embodiments described above will be basically described in relation to the embodiments described below among the plurality of embodiments. For matters not specifically mentioned, the same as in the foregoing embodiment or analogized to the foregoing embodiment may be adopted. In addition, in the structures corresponding to each other in the plurality of embodiments, the same reference numerals may be given to each other for convenience even if the structures are different from each other.

The gist of a local pressurizing device according to an embodiment of the present invention will be described first. Hereinafter, the first to fifth embodiments and the like will be described in more detail.

(Gist of local pressure device of an embodiment)

Fig. 1 (a) to 3 (b) are schematic diagrams showing the outline of the operations of the local pressurizing device 2 (hereinafter, sometimes simply referred to as "pressurizing device 2") and the injection device 9 according to the embodiment. The difference between the components of the pressurizing device 2 and the components of the injection device 9 may not be necessarily clear. In addition, a combination of both may also be considered as an injection device.

Fig. 1 (a), 2 (a) and 3 (a) schematically show the pressurizing device 2 and the injection device 9, and further show the states at different timings from each other in the molding cycle (more specifically, in the injection cycle). Fig. 1 (b) is an enlarged view of region Ib of fig. 1 (a). Fig. 2 (b) is an enlarged view of region IIb of fig. 2 (a). Fig. 3 (b) is an enlarged view of the region IIIb of fig. 3 (a).

Fig. 1 (a) and 1 (b) show a state in which an injection step of injecting a molding material (for example, molten metal 109, which is a metal in a molten state) into a mold 101 is performed. In the injection step, as indicated by an arrow a1, the plunger 21 (injection plunger) advances toward the mold 101, and the molten metal 109 in the sleeve 19 is pushed out into the mold 101 (space 107).

Conventionally, the pressurizing member 41 (pressurizing pin) of the pressurizing device 2 is in standby at the backward limit (the drive limit on the opposite side from the space 107) before the plunger 21 starts to advance (before the injection starts). On the other hand, in the present embodiment, the vehicle stands by at a position (for example, a forward limit) in front of the backward limit (space 107 side).

Fig. 2 (a) and 2 (b) show the subsequent states of fig. 1 (a) and 1 (b). When the injection process is continued, the melt 109 is filled into substantially the entire space 107. Fig. 2 (a) and 2 (b) show this state. In the description of the present embodiment, the case where such a state is achieved is sometimes referred to as filling completion. After the completion of the filling, the plunger 21 presses the melt 109 that has lost its return path, and the pressure of the melt 109 increases. In this case, a so-called impact pressure may be generated with a temporary and rapid pressure increase.

In the process from the start of injection to the completion of filling, the melt 109 reaches the position of the pressurizing member 41. Then, the pressurizing member 41 is pushed by the melt 109 and retreats as indicated by an arrow a2 (fig. 2 (a)) and an arrow a3 (fig. 2 (b)). The retraction of the pressurizing member 41 may occur immediately after the arrival of the melt 109, or may occur when the melt 109 is substantially filled in the space 107 and the pressure increases as described above. The pressing member 41 may or may not reach the retraction limit (in the illustrated example).

Fig. 3 (a) and 3 (b) show the subsequent states of fig. 2 (a) and 2 (b). When the filling is completed, the pressing member 41 advances as indicated by an arrow a4 (fig. 3 (a)) and an arrow a5 (fig. 3 (b)). Thereby, the melt 109 is locally pressurized. By this pressurization, for example, the possibility of occurrence of shrinkage cavities (voids accompanying solidification shrinkage of the melt) is reduced. After completion of filling, the plunger 21 may be advanced to assist in, for example, the pressure increase of the melt 109, or may be stopped at a position at the time of completion of filling.

As described above, in the pressurizing device 2 according to the embodiment, the pressurizing member 41 is positioned at the initial position (for example, the forward limit) forward of the backward limit when the melt 109 reaches the position of the pressurizing member 41. Then, the molten metal 109 is pushed and retracted from the initial position. Thus, various effects can be obtained.

For example, the impact pressure is absorbed by the retraction of the pressing member 41. By absorption of the impact pressure, the possibility of occurrence of burrs (portions formed by the overflow of the melt 109 to the outside of the space 107) is reduced. That is, the pressing member 41 can be effectively utilized not only as a member for local pressing but also as a member for absorbing impact pressure.

Further, for example, by detecting the backward movement of the pressurizing member 41, the arrival of the melt and/or completion of filling can be detected. Therefore, based on the detection of the backward movement of the pressing member 41, the timing of the start of the forward movement of the pressing member 41 can be appropriately checked. In more detail, for example, as follows.

As a comparative example with respect to the above embodiment, a method of determining the timing of starting the advance of the pressurizing member 41 based on the rise in the driving force of the driving portion (e.g., hydraulic cylinder) that drives the plunger 21 (in other words, the rise in the pressure from the melt 109 to which the plunger 21 is subjected) is exemplified. However, the pressure rise of the melt 109 at the position of the plunger 21 does not necessarily coincide with the arrival and/or pressure rise of the melt 109 at the position of the pressurizing member 41 due to the gradual solidification of the melt 109 during injection or the like. As a result, the timing at which the pressurizing member 41 starts to advance is not necessarily appropriate for the state of the melt 109 at the position of the pressurizing member 41. On the other hand, in the present embodiment, since the arrival and/or pressure rise of the melt 109 can be detected at the position of the pressurizing member 41, such a problem does not occur.

As another comparative example, a method in which a sensor (for example, a pressure sensor, a temperature sensor, or a power-on sensor) for detecting the arrival of the melt 109 is provided at an appropriate position of the mold 101 is exemplified. However, the same disadvantages as in the comparative example described above occur depending on the mounting position of the sensor. Such a sensor is provided at or near a position that can be exposed to the space 107 in contact with the melt 109. Therefore, durability against pressure and heat of the melt 109 is required. However, the sensor 43 (fig. 1 (b)) for detecting the backward movement of the pressing member 41 may not be exposed to the space 107, and may be disposed further rearward than the pressing member 41 as described later. Therefore, the durability required for the sensor 43 can be reduced. In addition, when the sensor 43 is a position sensor, the sensor may be used for feedback control when advancing the pressurizing member 41, unlike the sensor of the comparative example.

(First embodiment)

(Integral Structure of die casting machine)

Fig. 4 is a side view (a part includes a cross-sectional view) showing the configuration of a main part of the die casting machine DC according to the first embodiment. In the description with reference to fig. 4, the left side of fig. 4 is sometimes referred to as the front and the right side of fig. 4 is sometimes referred to as the rear for convenience.

The belt molding machine DC has: a die (a die 101) and a die casting machine 1 for holding the die 101. The die casting machine 1 is configured as a device for manufacturing a product (molded product, die casting product) made of a solidified molding material by injecting (filling) the molding material in a molten state into the interior (space 107) of the die 101.

The molding material is, for example, a metal such as aluminum. As described above, the metal in a molten state is sometimes referred to as a melt. Instead of the molding material in a molten state, the molding material in a solid-liquid coexisting state (semi-solidified state or semi-molten state) may be injected into the space 107.

The metal mold 101 includes, for example: a fixed die 103, and a movable die 105 opposed to the fixed die 103. A main portion of the space 107 is constituted between the fixed die 103 and the movable die 105. The fixed mold 103 is a mold that does not move. The movable die 105 is a die that moves in a direction (die opening and closing direction) opposite to the fixed die 103. The mold opening and closing direction is, for example, a horizontal direction. In fig. 4 and the like, for convenience, the cross section of the fixed die 103 or the movable die 105 is indicated by 1 hatching. But these molds may be either straight engraving or nested. In addition, the fixed die 103 and/or the movable die 105 may include a die base.

The die casting machine 1 has: a machine body 3 for performing mechanical operation, and a control device 5 for controlling the machine body 3. The machine body 3 includes, for example: a mold clamping device 7 for opening and closing the mold of the mold 101, an injection device 9 for injecting a molten metal into the space 107, and a not-shown extruding device for extruding a product formed by solidifying the molten metal from the fixed mold 103 or the movable mold 105.

A pressurizing device 2A (see fig. 5 described later) as a specific example of the pressurizing device 2 is included in the belt molding machine DC. At least a part of the pressurizing device 2A (for example, the pressurizing member 41 and the driving portion thereof) may be regarded as a component attached to the die 101 or may be regarded as a component of the die casting machine 1. When focusing on the respective components (e.g., the pressurizing device 2A) of the belt molding machine DC, the control device 5 may be regarded as a component of the respective components.

The structure and operation of the components other than the pressurizing device 2A may be known or may be innovative in the belt molding machine DC, in other words, may be various. The description of the structure and operation that can be referred to as a known structure and operation and are not important is appropriately omitted.

In the following description of the die casting machine 1, the following procedure is generally described.

Clamping device 7

Injection device 9

Control device 5

Other constructions of die-casting machines

Pressurizing device 2A

Action related to injection and local pressurization

Summary of the first embodiment

(Mold clamping device)

The mold clamping device 7 includes, for example: the die assembly comprises a base 11, a fixed die plate 13 fixed to the base 11, a movable die plate 15 movable in the die opening and closing direction on the base 11, and a plurality of (e.g., 4) connecting rods 17 inserted through these die plates. The fixed die connecting plate 13 and the movable die connecting plate 15 are opposed to each other in the die opening and closing direction. The fixed die attachment plate 13 holds the fixed die 103 on the surface opposite to the moving die attachment plate 15. The movable die plate 15 holds the movable die 105 on the surface opposite to the fixed die plate 13. The die 101 is opened and closed by moving the die-attaching plate 15 in the die opening and closing direction. In addition, by extending the tie bar 17 in the mold closed state, a clamping force corresponding to the extension amount of the mold 101 is applied.

(Injection device)

The injection device 9 is located behind the fixed die plate 13 (opposite to the moving die plate 15). The injection device 9 has: a sleeve 19 communicating with the space 107, a plunger 21 for pushing out the melt in the sleeve 19 to the space 107, and a driving part 23 for driving the plunger 21. Further, since the sleeve 19 and the plunger 21 can be regarded as consumable items, only the driving portion 23 can be regarded as an injection device.

The sleeve 19 is arranged to be inserted through the fixed die plate 13. The sleeve 19 may be inserted through the stent 103 (example of fig. 4) or through the stent (example of fig. 1 (a)). The sleeve 19 is a substantially cylindrical member, and is disposed so as to extend in the horizontal direction (front-rear direction). A supply port 19a for supplying a melt is opened in the upper surface of the sleeve 19.

The plunger 21 has: a plunger piece 21a sliding in the sleeve 19, and a plunger rod 21b fixed to the plunger piece 21 a. The plunger rod 21b extends in the front-rear direction, and the rear end thereof is coupled to the driving unit 23 via a coupling 25.

Fig. 4 shows a state before the start of injection. At this time, the plunger piece 21a is positioned in the sleeve 19 (at least partially) behind the supply port 19 a. In this state, the molten metal is injected into the supply port 19a by a liquid supply device or the like, not shown. Next, by the driving force of the driving section 23, the plunger piece 21a slides (advances) toward the space 107. Thereby, the melt is injected into the space 107.

The driving unit 23 may be, for example, hydraulic (hydraulic), electric, or hybrid (a combination of hydraulic and electric). In fig. 1 (a), a hydraulic driving unit 23 is illustrated. That is, the driving unit 23 includes: a hydraulic cylinder (injection cylinder 27) connected to the plunger 21, and a hydraulic device (not shown) for supplying a working fluid or the like to the injection cylinder 27.

The structure of the injection cylinder 27 is arbitrary. For example, the injection cylinder 27 may be of a single cylinder type (example of fig. 1 (a)) or of a booster type (see fig. 12 described later). The single cylinder type injection cylinder 27 (fig. 1 (a)) includes: a cylinder member 31, a piston 33 slidable in the cylinder member 31, and a piston rod 37 extending forward (toward the plunger 21) from the piston 33.

The cylinder part 31 is stationary. The interior of the cylinder member 31 is divided by the piston 33 into a rod side chamber 31r on the piston rod 37 side and a head side chamber 31h on the opposite side thereof. The piston rod 37 extends to the outside of the cylinder member 31, and its front end is coupled to the rear end of the plunger 21 via the coupling 25.

By supplying the working fluid to the head side chamber 31h, the piston 33 advances. Thereby, the plunger 21 coupled to the piston 33 via the piston rod 37 and the coupling 25 advances. Further, the melt in the sleeve 19 is injected into the space 107.

(Control device)

Although not specifically shown, the control device 5 may be configured to include a computer, for example. Although not specifically shown, the computer may include CPU (Central Processing Unit), ROM (Read Only Memory), RAM (Random Access Memory) and an external storage device, for example. The CPU executes programs stored in the ROM and/or the external storage device to constitute various functional units for performing various operations (including a control unit). The control device 5 may include a logic circuit that performs a predetermined operation, may include a power supply circuit, or may include a driver, and may be conceptualized. The control means 5 may be integrated in hardware in one place or may be distributed in a plurality of places.

(Other structures of die casting machine)

The belt molding machine DC may have various sensors. Then, the control device 5 can control each section based on the detection values of the various sensors.

Examples of the above-mentioned sensors are listed. Although not specifically shown, a position sensor for detecting the position of the plunger 21 and/or a sensor for detecting the driving force of the driving unit 23 may be provided, for example. Since the speed can be obtained by differentiation of the position, the position sensor can also be regarded as a speed sensor. As a sensor for detecting the driving force of the driving unit 23, for example, in a system in which the driving unit 23 has the injection cylinder 27, a pressure sensor for detecting the pressure of the head side chamber 31h (and a pressure sensor for detecting the pressure of the rod side chamber 31r as needed) may be used.

The sensor that detects the position of the plunger 21 is used, for example, to control the injection speed (in other words, the speed of the plunger 21). The sensor that detects the driving force of the driving portion 23 is used to control the injection pressure (in other words, the pressure applied by the plunger 21 to the molding material). However, as will be described later, in the present embodiment, the casting pressure can be achieved by pressure control by the pressurizing device 2, and control of the injection pressure is not necessary.

(Pressurizing device)

Fig. 5 is a schematic diagram showing the structure of the pressurizing device 2A.

As described with reference to fig. 1 (a), the pressurizing device 2A has: a pressurizing member 41 for pressurizing the melt, and a sensor 43 for detecting the backward movement of the pressurizing member 41. The pressurizing device 2A includes a driving unit 45A as a specific example of the driving unit 45 (fig. 1 (a)) for driving the pressurizing member 41.

The driving unit 45A may be configured appropriately, such as hydraulically or electrically. In the first embodiment, the hydraulic structure is exemplified as the driving unit 45A. The hydraulic driving unit 45A includes: a hydraulic cylinder (a pressure cylinder 47), and a hydraulic device 49 for supplying a hydraulic fluid to the pressure cylinder 47.

In the following description of the pressurizing device 2A, the following procedure is generally described.

Pressurizing member 41

Pressure cylinder 47

Sensor 43

Hydraulic device 49

(Pressing means)

The pressing member 41 may be substantially pin-shaped (in the illustrated example) or may be other than pin-shaped, with the advancing/retreating direction being the longitudinal direction. As an example of the latter, a block shape in which the diameter of the pressing member 41 is larger than the length of the pressing member 41 in the advancing and retreating direction is given. The cross section of the pressing member 41 perpendicular to the advancing and retreating direction may be circular (in the illustrated example), or may be other than circular. The size of the pressing member 41 is also arbitrary.

As shown in fig. 1 b, the pressing member 41 may be formed in a tapered shape in which the diameter decreases as at least a part of the tip side (space 107 side) is closer to the tip side. In this case, the pressing member 41 is easily pulled out from the solidified molding material. The range of taper can be appropriately set. In the illustrated example, when the pressing member 41 is located at the forward limit, the entire portion of the pressing member 41 located in the space 107 is tapered. Of course, the pressing member 41 may be formed in a shape other than a tapered shape (for example, a shape having a constant diameter) of the tip.

The size of the pressing member 41 is arbitrary. For example, when D is the diameter of the tip of the pressurizing member 41 (for example, the equivalent circle diameter based on the area where the pressure in the forward direction is applied to the melt) and D is the diameter of the tip of the plunger 21, D/D may be 0.2 or more and 0.5 or less. Of course, it may be outside this range.

The pressing member 41 may be disposed on the fixed die 103 (in the illustrated example) or on the movable die 105. In the description of the present embodiment, for convenience, the description is sometimes given on the premise that the pressurizing member 41 is disposed on the fixed die 103.

The pressing member 41 may be partially or entirely slid (or may be abutted) in the advancing and retreating directions with respect to the mold (the fixed mold 103 or the movable mold 105), for example. The rear end side portion (the portion connected to the driving portion 45A) of the pressing member 41 may be located outside the mold or may be located entirely inside the mold. As the latter example, a mode in which the rear end side portion of the pressing member 41 is located in a space constituted by a die base, not shown, is exemplified.

The advancing and retreating direction of the pressing member 41 may be an appropriate direction. For example, the advancing and retreating direction may be a mold opening and closing direction (left-right direction in fig. 4), or may be a direction intersecting (orthogonal to or inclined to) the mold opening and closing direction. However, if the advancing and retreating direction is the mold opening and closing direction, for example, the pressing member 41 may be pulled out from the molded article in association with an operation (the mold opening operation and/or the pressing operation may be performed) of peeling the molded article from the mold in which the pressing member 41 is disposed.

The arrangement position of the pressurizing member 41 with respect to the space 107 can be appropriately set. For example, as shown in fig. 1 (a) and 1 (b), the space 107 has: the pressurizing member 41 having the product portion 107a having a shape corresponding to the product shape, the runner 107e for guiding the melt from the sleeve 19 to the product portion 107a, and the overflow portion 107b into which the remaining melt flows can pressurize the melt in any of these spaces.

In the example of fig. 1 (a), the pressurizing member 41 is configured to pressurize the melt flowing into the overflow portion 107 b. In general, the overflow portion 107b is connected to the outer periphery of the product portion 107a (particularly, a position away from the sleeve 19) when viewed in the mold opening/closing direction. Therefore, the pressurizing member 41 for pressurizing the melt in the overflow portion 107b can apply pressure to the melt on the outer peripheral side where it is difficult to apply pressure by the plunger 21, out of the melt in the product portion 107 a. As a result, for example, the melt in the product portion 107a is likely to uniformly apply pressure to the entire melt. Further, in the case of molding a large product, the necessity of increasing the pressure applied to the melt by the plunger 21 can be reduced. From another point of view, the necessity of upsizing the die casting machine 1 can be reduced.

As shown in fig. 1 b, the fixed mold 103 (mold in which the pressing member 41 is disposed) may have a recess 107c in which the tip end side portion of the pressing member 41 is inserted and removed on the surface of the movable mold 105. The concave portion 107c may be formed to have a larger diameter than the distal end side portion of the pressing member 41, for example, or may be formed to have an inverted taper shape having a larger diameter as the concave portion is closer to the movable die 105. The volume for the pressurizing member 41 to enter and exit the space 107 is secured in the space 107 by the recess 107c. In addition, the solidified molding material is easily pulled out from the stent 103 by the reverse taper shape. Of course, the stent 103 may not have such a concave portion 107c, and a concave portion 107c other than an inverted cone may be formed.

The forward limit and the backward limit of the pressing member 41 may be defined by a member or a portion (stopper) against which the pressing member 41 abuts when the pressing member 41 advances or retreats, or may be defined by a drive limit of the driving portion 45 that drives the pressing member 41, in the mold 101 or the like. As examples of the latter drive limit, for example, a forward limit and a backward limit of the piston 55 (described later) in the pressure cylinder 47 with respect to the cylinder member 53 (described later) can be cited. In the description of the present embodiment, the illustration of the members defining the forward limit and the backward limit is omitted as appropriate.

The number of the pressing members 41 may be appropriately set, and may be 1 or 2 or more. However, in the description of the present embodiment, only 1 pressing member 41 is basically illustrated in order to avoid complicating the drawing.

(Pressure cylinder)

As shown in fig. 5, the pressure cylinder 47 includes, for example: a cylinder member 53, a piston 55 slidable inside the cylinder member 53, and a piston rod 57 extending from the piston 55 to the outside of the cylinder member 53.

The cylinder member 53 is, for example, a substantially cylindrical member. The shape of the cross section of the interior of the cylinder member 53 is, for example, circular. The outer shape (outer shape) of the cylinder member 53 may be formed in an appropriate shape such as a rectangular parallelepiped shape. The piston 55 is, for example, a substantially cylindrical member, and is axially slidable inside the cylinder member 53. The space inside the cylinder member 53 is divided by the piston 55 into a rod side chamber 53r on the piston rod 57 side and a head side chamber 53h on the opposite side thereof. The piston rod 57 is, for example, a substantially cylindrical member. The diameter of the piston rod 57 is smaller than the diameter of the piston 55. The difference value thereof can be appropriately set.

The pressure cylinder 47 is disposed coaxially with the pressure member 41 on the opposite side (right side in fig. 5) of the pressure member 41 from the space 107, for example, and faces the piston rod 57 side toward the pressure member 41. The cylinder member 53 is fixed relative to the fixed mold 103 (the mold in which the pressurizing member 41 is disposed). For example, the cylinder member 53 is fixed to the fixed die 103 and/or the fixed die plate 13 with bolts or the like. The front end of the piston rod 57 is coupled to the rear end of the pressing member 41 by a suitable coupling (reference numeral omitted). Therefore, for example, in the pressure cylinder 47, when the working fluid is supplied to the head side chamber 53h, the piston 55 moves toward the rod side chamber 53 r. Further, the pressurizing member 41 coupled to the piston 55 via the piston rod 57 advances toward the space 107.

In contrast to the above description, the cylinder member 53 may be fixed to the pressing member 41 so that the piston rod 57 is fixed to the fixed die 103. The direction of the pressure cylinder 47 may be opposite to the above description. That is, there may be three types of combinations of which of the cylinder member 53 and the piston rod 57 is fixed and which direction the piston rod 57 extends. In the above, the cylinder chamber to which the working fluid is supplied when the pressurizing member 41 is advanced toward the space 107 may be the rod side chamber 53r. In the description of the present embodiment, for convenience, the description is sometimes given on the premise that the piston rod 57 faces the direction of the pressurizing member 41 and the cylinder member 53 is not moved in the drawing.

The number of the pressing members 41 driven by 1 pressing cylinder 47 may be 1 (in the illustrated example), or may be2 or more. In the latter case, for example, in order to be able to analogize from a known extruding device, a plate-like member orthogonal to the piston rod 57 may be fixed to the tip of the piston rod 57, and a plurality of pressing members 41 may be fixed in parallel to the plate-like member. In the description of the present embodiment, basically, the manner illustrated (the manner in which 1 pressurizing cylinder 47 drives 1 pressurizing member 41) is taken as an example.

As will be understood from the following description, in the present embodiment, the movement of the piston 55 (the retraction of the pressurizing member 41 from the space 107 by the driving unit) by the supply of the working fluid to the rod side chamber 53r is not necessarily performed. Therefore, the rod side chamber 53r may be filled with the working fluid or may be not filled with the working fluid. In the latter case, for example, the rod side chamber 53r may be opened to the atmosphere. In this case, for the purpose of lubrication or the like, a small amount of oil may be disposed as the working fluid in the rod side chamber 53 r. When the rod-side chamber 53r is filled with the working fluid, only a short portion of the working fluid may be supplied from the tank or the driving source (e.g., pump) when the volume of the rod-side chamber 53r is expanded.

Further, the pressure cylinder 47 may be configured such that the piston 55 extends from the cylinder member 53 to the opposite side to the head side chamber 53h (in other aspects, the diameter of the piston 55 is the same as the diameter of the piston rod 57), and the rod side chamber 53r is not provided. However, in the description of the present embodiment, for convenience, the description is sometimes given on the premise of the illustrated embodiment (the embodiment in which the pressure cylinder 47 has the rod side chamber 53 r).

(Sensor for detecting the retreat of the pressing Member)

As described above, the sensor 43 detects the retreat of the pressing member 41. The specific configuration of the sensor 43 may take various forms. The following list a few examples.

The sensor 43 may be, for example, a limit switch, and is turned ON (ON) (or turned OFF (OFF)) when the pressing member 41 moves backward from the initial position (for example, the forward limit) to a predetermined position. The limit switch can be of a contact type or a non-contact type.

The sensor 43 may be, for example, a position sensor that detects the position (in other viewpoints, the amount of backward movement) of the pressing member 41. As the position sensor, for example, a linear encoder is cited.

When the pressure member 41 is retracted according to the operation mode of the pressure cylinder 47, the pressure of the head side chamber 53h increases. Therefore, a pressure sensor 71H (see fig. 6 described later) that detects the pressure of the head side chamber 53H may also be used as the sensor 43.

It is to be understood from the above specific examples that the detection of the backward movement may be a detection of the presence or absence of backward movement (for example, based on a limit switch) or a detection of the amount of backward movement (for example, based on a position sensor). The above specific examples may be used in combination. The structure of the sensor 43, the amount of backward movement when the sensor 43 detects backward movement, and the like may be the same as or different from each other among the plurality of pressing members 41 (or the plurality of driving portions 45).

The position of the sensor 43 may be any position as long as the backward movement of the pressing member 41 can be detected. For example, the limit switch or the position sensor may directly detect the backward movement of the pressing member 41 (see fig. 1 b), or may detect the backward movement (movement) of another member coupled to the pressing member 41 (fig. 5). In the example of fig. 5, a detection target portion 44 fixed to the piston 55 and extending rearward (on the opposite side from the pressurizing member 41) from the cylinder member 53 is provided. The sensor 43 detects the backward movement of the detection target portion 44. As understood from the description of the pressure cylinder 47, the detected portion 44 may be located inside the mold 101 or may be located outside the mold 101.

(Hydraulic device of pressurizing device)

The hydraulic device 49 shown in fig. 5 includes, for example, a low-pressure circuit 59L and a high-pressure circuit 59H as hydraulic circuits for supplying the hydraulic fluid or the like to the pressure cylinder 47. In the following, the hydraulic circuit 59 (shown in fig. 6) may be referred to without distinguishing between the two. The low-pressure circuit 59L can apply a hydraulic pressure to the pressure cylinder 47 that is lower than the hydraulic pressure supplied to the pressure cylinder 47 by the high-pressure circuit 59H.

When the pressurizing member 41 is positioned at the initial position (e.g., the forward limit) before the partial pressurization (fig. 1 (a) and 1 (b)), the working fluid is supplied from the low-pressure circuit 59L to the head-side chamber 53 h. When the pressure of the melt 109 is applied to the pressurizing member 41 (fig. 2 (a) and 2 (b)), the pressurizing member 41 retreats against the hydraulic pressure from the low-pressure circuit 59L. When the pressurizing member 41 is advanced to locally pressurize (fig. 3 (a) and 3 (b)), the working fluid is supplied from the high-pressure circuit 59H to the head-side chamber 53H.

The low-pressure circuit 59L and the high-pressure circuit 59H may have the same structure or may have completely different structures. The low-pressure circuit 59L and the high-pressure circuit 59H may be partially shared. Hereinafter, the configuration of the low-pressure circuit 59L and the high-pressure circuit 59H will be described as an example in the same manner as each other except for the difference in pressure (and the specific design matters caused by the difference in pressure).

Fig. 6 is a circuit diagram showing a specific example of the configuration of the hydraulic device 49.

The hydraulic circuit 59 shown in the drawing may be regarded as either one of a low-pressure circuit 59L and a high-pressure circuit 59H. The components other than the hydraulic circuit 59 may be shared by the low-pressure circuit 59L and the high-pressure circuit 59H.

The hydraulic circuit 59 has the following components, for example. A reservoir 61 as a hydraulic pressure source for supplying the hydraulic fluid to the pressure cylinder 47. A control valve 63 that controls the flow of the working fluid between the reservoir 61 and the pressure cylinder 47. A check valve 75 that controls the flow of the working fluid for the accumulator 61.

The hydraulic device 49 has the following components, for example, in addition to the hydraulic circuit 59. A back pressure eliminating cylinder 65 for reducing the back pressure of the pressurizing cylinder 47. A pump 67 as a hydraulic pressure source of the accumulator 61. A tank 69 for storing the working fluid. A pressure sensor 71R and 71H for detecting the pressure of the pressure cylinder 47. A flow rate sensor 73 that detects the flow rate of the hydraulic fluid discharged from the pressure cylinder 47. Various valves (77A, 77R, and 77H) for controlling the flow of the hydraulic fluid in the hydraulic device 49. These structures may also be regarded as constituent elements of the hydraulic circuit 59.

In the following description of the hydraulic device 49, the following procedure is generally described.

Reservoir 61

Control valve 63

Check valve 75

Back pressure eliminating cylinder 65

Pump 67 and tank 69

Pressure sensors 71R and 71H and flow sensor 73

Various valves (77A, 77R and 77H)

Structure of hydraulic device 49 in the case where 2 or more pressure cylinders 47 are provided

(Reservoir)

The reservoir 61 may be constituted by a reservoir of a suitable form such as a weight type, a spring type, a pneumatic type (including an air-pressure type), a cylinder type, a balloon type, or the like. For example, the reservoir 61 is a pneumatic, air-cylinder, or air-bag reservoir, and the pressure is accumulated by compressing a gas (e.g., air or nitrogen) held in the reservoir 61.

The pressure of the reservoir 61 in the low-pressure circuit 59L (the pressure fluctuation due to the release of the working fluid is negligible here) is lower than the pressure of the reservoir 61 in the high-pressure circuit 59H. Thereby, the low-pressure circuit 59L can supply a lower pressure than the pressure supplied by the high-pressure circuit 59H to the pressure cylinder 47 (for example, the head side chamber 53H). The specific value of the pressure of the reservoir 61 may be appropriately set. For example, the pressure of the reservoir 61 of the high-pressure circuit 59H may be 13MPa or more and 14MPa or less.

(Control valve)

The control valve 63 is configured to at least permit and prohibit communication between the reservoir 61 and the head side chamber 53h, for example. The head side chamber 53h is connected to the reservoir 61, and for example, the working fluid is supplied from the reservoir 61 to the head side chamber 53h, whereby the pressurizing member 41 is advanced. In addition, in the case where the reservoir 61 of the low-pressure circuit 59L is connected to the head side chamber 53h, for example, when the pressurizing member 41 retreats due to the impact pressure, the pressure thereof is absorbed by the reservoir 61. Further, the absorption of the impact pressure (at least a part thereof) may be achieved by compression of the working fluid, independently of the reservoir 61 of the low-pressure circuit 59L.

For example, by cooperation of the control valve 63 of the low-pressure circuit 59L and the control valve 63 of the high-pressure circuit 59H, one of the reservoir 61 of the low-pressure circuit 59L and the reservoir 61 of the high-pressure circuit 59H can be selectively connected to the head-side chamber 53H. Therefore, the 2-circuit control valve 63 may also be regarded as a switching valve that selectively connects the low-pressure circuit 59L and the high-pressure circuit 59H to the head-side chamber 53H as a whole. Unlike the example shown in fig. 1, this switching valve may be constituted by a valve having 1 valve body.

In the control valve 63, a specific structure for allowing and prohibiting connection between the reservoir 61 and the head side chamber 53h may be an appropriate structure. In the illustrated example, the control valve 63 is configured to function as a 4-port, 3-position switching valve. In the first position, the reservoir 61 (or the pump 67) is connected to the head side chamber 53h, and the tank 69 is connected to the rod side chamber 53 r. In the second position, the reservoir 61 is connected to the rod side chamber 53r, and the tank 69 is connected to the head side chamber 53h, contrary to the above. In the third position, any of the connections described above is disabled.

By positioning the control valve 63 at the first position, for example, the pressure member 41 can be advanced by supplying the working fluid from the reservoir 61 to the head side chamber 53 h. At this time, the working fluid discharged from the rod side chamber 53r is discharged to the tank 69. By setting the control valve 63 to the second position, for example, the pressurizing member 41 can be retracted in contrast to the above. In addition, by positioning the control valve 63 at the third position, for example, the pressurizing member 41 can be stopped.

In the illustrated example, the control valve 63 is configured to function as a flow rate control valve capable of controlling the flow rate of the working fluid. The flow control valve is, for example, a pressure-compensated flow control valve capable of maintaining a constant flow rate even if there is a pressure fluctuation. The flow control valve is, for example, a servo valve used in a servo mechanism, and is capable of continuously (continuously, arbitrarily) modulating a flow rate according to an input signal.

The control valve 63 serving as a flow control valve functions as a constituent element of the meter-in circuit and/or meter-out circuit when the working fluid is supplied from the reservoir 61 to the head side chamber 53h, for example. This can control the advancing speed of the pressurizing member 41, and perform local pressurization corresponding to the solidification state.

The specific configuration of the control valve 63 functioning as the switching valve and/or the flow control valve described above is also arbitrary. In the illustrated example, the control valve 63 has a main valve 63a and a pilot valve 63 b. The main valve 63a controls the flow of the working fluid at the above 3 positions through the reservoir 61, the tank 69, the head side chamber 53h, and the rod side chamber 53 r. The pilot valve 63b is driven by an electromagnetic driving method, and introduces a pilot pressure to the main valve 63a to control the main valve 63a.

The control valve 63 may have a variety of configurations other than the illustrated example. For example, the control valve 63 may be a direct-acting valve or a pilot-operated check valve. As described above, the rod side chamber 53r does not necessarily need to be supplied with the working fluid, and a flow path and a valve for connecting the rod side chamber 53r to the reservoir 61 (or the pump 67) and the tank 69 may not be provided.

(One-way valve)

The check valve 75 allows and prohibits the supply of the hydraulic fluid from the pump 67 to the hydraulic circuit 59. Thus, for example, the reservoir 61 of the low-pressure circuit 59L and the reservoir 61 of the high-pressure circuit 59H can be selectively filled with the working fluid. The valve having such a function may have a structure other than a check valve, or may be a single valve shared by the low-pressure circuit 59L and the high-pressure circuit 59H. In the illustrated example, the check valve 75 is provided to allow the working fluid to flow from the pump 67 to the reservoir 61, and to prohibit the reverse flow thereof, and to prohibit both of the flows by introducing the pilot pressure.

(Back pressure eliminating Cylinder)

The back pressure cancellation cylinder 65 is connected to the midway of the flow path connecting the control valve 63 (the rod side chamber 53r in other aspects) and the tank 69. When the working fluid flows from the rod side chamber 53r to the tank 69, a part of the working fluid flows into the back pressure eliminating cylinder 65. This reduces the rise in pressure (back pressure) of the rod side chamber 53r when the piston 55 (the pressurizing member 41) advances, for example. Further, the advancing speed of the pressing member 41 (in other aspects, the responsiveness of the pressing member 41) is improved.

The structure of the back pressure eliminating cylinder 65 may be appropriate. For example, the back pressure eliminating cylinder 65 may be constituted by a reservoir. The description of the reservoir 61 may be made by referring to the back pressure eliminating cylinder 65 as long as no contradiction or the like occurs. The capacity and pressure of the back pressure cancellation cylinder 65 can be appropriately set.

The pressure of the back pressure eliminating cylinder 65 may be set relatively low. This allows the working fluid to be stored quickly. For example, in the case where the back pressure cancellation cylinder 65 is a cylinder type reservoir, the pressure at which the piston 65a of the back pressure cancellation cylinder 65 is located at the drive limit on the working fluid release side (lower side in fig. 6) is lower than the pressure of the reservoir 61 of the low pressure circuit 59L.

The pressure at which the piston 65a is located at the drive limit on the side of releasing the working fluid is, for example, higher than the tank pressure. Thus, when the working fluid does not flow from the control valve 63 to the tank 69, the piston 65a moves to the drive limit on the side where the working fluid is released. Further, the working fluid of the back pressure cancellation cylinder 65 is discharged to the tank 69.

(Pump and tank)

The pump 67 and the tank 69 may be formed in various ways, and for example, a known structure may be used. The pump 67 and/or the tank 69 may be shared with hydraulic devices other than the hydraulic device 49 of the pressurizing device 2A (for example, hydraulic devices of the injection device 9).

The pump 67 may be driven as needed or may be driven at all times (in this case, the required valves are not shown). For example, the pump 67 facilitates pressure accumulation of the reservoir 61. In addition to this, for example, when the piston 55 of the pressure cylinder 47 is retracted, the pump 67 may apply the working fluid to the rod side chamber 53r instead of the reservoir 61 (a valve necessary in this case is not shown). For example, the pump 67 may supply the working fluid to the head side chamber 53h in cooperation with the reservoir 61.

The tank 69 is formed, for example, in an atmosphere open structure. Therefore, the pressure of the flow path or the like connected to the tank 69 is substantially atmospheric pressure. The tank 69 contributes to recovery of the working fluid discharged from the pressure cylinder 47 (the rod side chamber 53r or the head side chamber 53 h), for example, as described above.

(Pressure sensor and flow sensor)

The pressure sensor 71R detects the pressure of the rod side chamber 53R. The pressure sensor 71H detects the pressure of the head side chamber 53H. The control device 5 can determine the driving force generated by the pressure cylinder 47, for example, based on the detected pressure in the rod side chamber 53r and the detected pressure in the head side chamber 53h, and can further determine the pressure applied to the melt by the pressure member 41. The driving force applied to the pressurizing member 41 by the pressurizing cylinder 47 in the advancing direction may be determined based only on the pressure of the head side chamber 53h, or the pressure sensor 71R may be omitted. The specific structure of the pressure sensors 71R and 71H may be various, for example, a known structure.

The flow sensor 73 detects the flow rate of the working fluid discharged from the rod side chamber 53 r. Thus, for example, the advance distance of the pressing member 41 can be detected. Such a sensor is particularly useful, for example, in a system in which the sensor 43 that detects the retreat of the pressing member 41 is not a position sensor. In addition, the flow sensor 73 may not be provided. The specific structure of the flow sensor 73 may be various, for example, a known structure may be employed.

(Various valves)

The valves 77A, 77R, and 77H are used, for example, at the time of maintenance of the pressurizing device 2A. These valves may be constituted by, for example, shut-off valves that are manually opened and closed. In addition, these valves may not be provided.

The valve 77A is provided in the flow paths of the connection rod side chamber 53r and the head side chamber 53 h. During the forming cycle, valve 77A is closed. During maintenance, valve 77A is opened and the working fluid is circulated. Thereby, air can be discharged from the pressure cylinder 47. Further, the operation of the pressure cylinder 47 is stabilized.

The valve 77R is located between the rod side chamber 53R and the pressure sensor 71R. The valve 77H is located between the head side chamber 53H and the pressure sensor 71H. Valves 77R and 77H are opened when the forming cycle is performed.

Although not particularly shown, a check valve may be provided that allows the working fluid to flow from the tank 69 to the rod side chamber 53r, prohibits the flow in the opposite direction, and allows both flows by introducing the pilot pressure. In this case, for example, in a state where the pilot pressure is introduced into the check valve, the working fluid is supplied from the low-pressure circuit 59L to the head-side chamber 53h, and the pressurizing member 41 is moved to the initial position. Before the pressure member 41 reaches the forward limit, the introduction of the pilot pressure is stopped, and the discharge of the working fluid from the rod side chamber 53r is inhibited. Therefore, the pressing member 41 can be stopped at an arbitrary position. That is, an arbitrary position before the retraction limit may be set as the initial position, and a forward force may be applied to the pressing member 41 at the initial position. When the pressurizing member 41 is pushed by the melt and retreats, the working fluid is supplied from the tank 69 to the rod side chamber 53r via the check valve. After that, when the working fluid is supplied from the high-pressure circuit 59H to the head-side chamber 53H and locally pressurized, the pilot pressure is introduced again to allow the working fluid to be discharged from the rod-side chamber 53 r.

(Structure of a Hydraulic device in the case where 2 or more pressure cylinders are provided)

In the hydraulic device 49, a combination of components (for example, the pressure cylinder 47, the pressure sensors 71H and 71R, and the control valve 63) surrounded by two-dot chain lines is referred to as a unit 60. The hydraulic device 49 may have a plurality of units 60. That is, 2 or more pressure cylinders 47 (or 2 or more pressure members 41 in another aspect) can be controlled independently of each other. As described above, 1 pressurizing cylinder 47 may drive 1 pressurizing member 41, or 2 or more pressurizing members 41 may be driven. The 2 or more pressing members 41 may be driven by driving units 45 having different structures (for example, a driving unit having a pressing cylinder 47 and a driving unit not having a pressing cylinder 47).

(Action of injection and local pressurization)

Fig. 7 is a diagram for explaining the injection and the local pressurization operation. Note that in the description of this figure, the pressurizing device 2A may be represented as a constituent element of the injection device 9 for convenience, or the partial pressurizing may be represented as a part of the injection process.

In fig. 7, the horizontal axis represents time t, and the time point is the later the closer to the right. The left vertical axis represents the velocity V, and the higher the upper velocity is. The right vertical axis represents the pressure P, and the higher the upper side pressure.

Line LV represents the time-dependent change in injection speed (speed of plunger 21). Line LP represents the time-dependent change in injection pressure. The injection pressure is the pressure exerted by the plunger 21 on the melt.

Line LC represents the time-dependent change in casting pressure. The casting pressure is, for example, the pressure of the melt in the product portion 107a of the mold 101 after the completion of filling, and is different from the injection pressure in the description of the present embodiment. In the following description, the casting pressure may be merely the final pressure (final pressure) after the rise. The pressure of the melt in the product portion 107a varies strictly according to the position in the product portion 107 a. The casting pressure shown here may be regarded as a representative value of the actual pressure in the product portion 107a, for example, or may be regarded as a target value of the casting pressure set without taking such tightness into consideration.

Line LB represents a flash generation (run-out) limit curve. The flash generation limit curve is a curve showing the time-dependent change in the upper limit value of the pressure of the molding material (melt) in which no flash is generated. The control device 5 may calculate a combination of time and pressure represented by the curve based on the calculation formula, or may refer to time-series data to determine the combination. A calculation method for generating a limit curve by flash is known, and can be calculated by a calculation formula described in, for example, japanese patent application laid-open No. 2019-13933.

Line LS represents a time-dependent change in pressure after converting the driving force of the driving unit 45A to drive the pressurizing member 41 toward the space 107 into a pressure that can be applied to the melt by the pressurizing member 41 (the tip thereof). Since "pressure can be applied", line LS also indicates before pressurization (for example, before the melt reaches the pressurizing member 41). After the start of pressurization (for example, after the melt reaches the pressurizing member 41), the pressure indicated by the line LS is the pressure actually applied to the melt by the pressurizing member 41. Here, it is assumed that the pressurizing member 41 pressurizes the molten liquid in a portion other than the product portion 107a or in the outer peripheral portion of the product portion 107 a. Therefore, the pressure shown by the line LS does not coincide with the representative value of the pressure of the product portion 107a or the casting pressure (line LC) as the target value of the representative value.

The speed and pressure indicated by the lines LV, LP, LC, and/or LS may be regarded as indicating target values or may be regarded as indicating actual values (for example, actual values detected by sensors). The target value may be set by an input of the user or by an operation of the control device 5.

The die casting machine 1 sequentially performs, for example, low-speed injection (time t0 to t 1), high-speed injection (time t1 to t 2), pressurization and pressure maintaining (time t2 to t). That is, as shown by line LV, the die casting machine 1 performs low-speed injection in which the plunger 21 is advanced at a relatively low speed (speed V _L) from the viewpoint of preventing the molten metal from being involved in air or the like in the initial stage of injection. Next, as shown by a line LV, the die casting machine 1 performs high-speed injection for advancing the plunger 21 at a relatively high speed (speed VH) from the viewpoint of filling the melt so as not to delay solidification of the melt, and the like. Next, as shown by line LC, the die casting machine 1 performs pressurization for raising the melt in the product portion 107a from the viewpoint of eliminating the blow holes (shrinkage holes) of the molded product, and the like. Then, as indicated by a line LC, the die casting machine 1 performs pressure maintaining for maintaining the final pressure obtained by the pressurization.

Typically, the casting pressure (line LC) is mainly achieved by the injection pressure (line LP) applied to the melt by the plunger 21. However, in the illustrated example, the ratio of the pressure (line LS) applied to the melt by the pressurizing member 41 to the casting pressure increases. The specific case is as follows.

In low-speed injection, the injection pressure is a low pressure that is relatively low. Thereafter, when the high-speed injection is started (time t 1), the injection pressure also rises. Further, when the filling of the melt is substantially completed (time t 2), the injection pressure increases rapidly to reach the pressure P1 because the melt loses its passable portion. In the illustrated example, the pressure P1 is lower than the casting pressure.

In general, in the manner that the pressure P1 is lower than the casting pressure at the completion of filling, the injection device 9 performs an action for pressurizing so that the injection pressure reaches the casting pressure higher than the pressure P1. Examples of such an operation include an operation of switching a reservoir for supplying the working fluid to the head side chamber 53h to a reservoir for pressurizing, and an operation of supplying the working fluid to the rear of a pressurizing piston (see fig. 12 described later).

However, in the illustrated example, the injection device 9 does not perform the action for pressurizing as described above. Instead, local pressurization by the pressurizing device 2A is performed, thereby realizing casting pressure. Specifically, in the illustrated example, when the injection pressure reaches the pressure P1 (time t 2), the driving of the pressure cylinder 47 by the high-pressure circuit 59H is started, and the local pressurization is started. At this time, the locally pressurized pressure P2 is higher than the casting pressure (target value), for example, and lower than the burr generation limit curve.

In addition, the pressure P2 may be set higher than the plastic deformation resistance. As the value of the plastic deformation resistance, for example, a yield point at the temperature of the molding material at the completion of the melt (the former when the upper yield point occurs and the yield point decreases) may be used. The pressure P2 may be set higher than the plastic deformation resistance by the user, or may be set higher than the plastic deformation resistance by the control device 5 having the plastic deformation resistance information. In the latter case, the control device 5 may acquire information of the plastic deformation resistance itself or information for determining the plastic deformation resistance through an input of the user.

The magnitude of the pressure P2 is arbitrary compared to the pressure P1. For example, when the molded article is thin, the pressure P2 may be 1.1 times or more and 2.0 times or less of the pressure P1. When the molded article is thick or medium-thick, the pressure P2 may be 1.5 times or more and 4.0 times or less of the pressure P1. Of course, the ratio of both may be outside the above range.

Before the start of the local pressurization (before time t 2), the pressure indicated by the line LS is smaller than the injection pressure at the completion of the filling, that is, the pressure P1 (in other aspects, the maximum value of the injection pressure). From another point of view, the driving force (hereinafter, sometimes referred to as initial force) that brings the pressing member 41 into the initial position (e.g., the forward limit) is smaller than the force applied to the pressing member 41 on the assumption that the pressure P1 is applied to the pressing member 41 from the front. Thus, after the melt reaches the position of the pressurizing member 41, the pressurizing member 41 is retracted at an appropriate timing. In the present embodiment, the working fluid is supplied from the low-pressure circuit 59L to the head-side chamber 53h to generate an initial force. The initial force may be applied to the pressurizing member 41 at an appropriate timing, and in the illustrated example, the initial force is applied from the start of injection (time point t 0).

Fig. 8 is a flowchart showing an example of the procedure of the process executed by the control device 5 to realize the above-described operation.

In step ST1, the control device 5 performs initial settings related to various molding conditions based on an input operation or the like by the user. As the conditions set in the initial setting, for example, values at appropriate time points of the injection speed (line LV), the injection pressure (line LP), the casting pressure (line LC), and the pressure (line LS) applied to the melt by the pressurizing member 41 shown in fig. 7 are cited. This value may for example comprise pressures P1 and P2. In addition, a value required for calculating a limit curve of the burr generation may be set.

In step ST2, the control device 5 determines whether or not the start condition of injection is satisfied. The start condition may be, for example, that the mold closing of the fixed mold 103 and the movable mold 105 has been completed, that information indicating that the melt is supplied to the sleeve 19 has been obtained, or the like. Then, the control device 5 waits until the start condition is satisfied (step ST2 is repeated), and when it is determined that the start condition is satisfied, the flow proceeds to steps ST3 and ST6.

Steps ST3 to ST5 show steps of the process related to the injection by the injection device 9. On the other hand, steps ST6 to ST10 show steps of the process related to the local pressurization by the pressurizing device 2A. These treatments are, for example, at least partially performed in parallel.

In step ST3, the control device 5 controls the driving portion 23 of the injection device 9 to advance the plunger 21. For example, the control device 5 controls a hydraulic device (not shown) of the injection device 9 so as to supply the working fluid to the head side chamber 31h of the injection cylinder 27. Thus, low-speed injection and high-speed injection are performed.

In step ST4, the control device 5 determines whether or not the injection pressure has reached the target value at the time of completion of filling, that is, the pressure P1. Then, the control device 5 stands by (continues the high-speed injection) in the negative determination, and proceeds to step ST5 in the affirmative determination.

In step ST5, the control device 5 stops the plunger 21 from advancing. For example, the control device 5 stops supplying the working fluid to the head side chamber 31 h. In this case, the discharge of the working fluid from the head side chamber 31h may be inhibited so that the plunger 21 does not retract due to the pressure of the molten metal.

In step ST6, the control device 5 controls the hydraulic device 49 to move the pressing member 41 (pressing pin) toward the initial position (e.g., the forward limit). That is, the control valve 63 of the low-pressure circuit 59L is controlled to supply the working fluid from the reservoir 61 of the low-pressure circuit 59L to the head-side chamber 53h of the pressure cylinder 47. In addition, this step may be performed at any time as long as it is performed before the melt reaches the position of the pressurizing member 41. For example, it may be performed before step ST 2.

In step ST7, the control device 5 determines whether or not the pressurizing member 41 is pushed by the melt and retreats based on the signal from the sensor 43. Then, the control device 5 stands by in the negative determination (repeats step ST 7), and proceeds to step ST8 in the affirmative determination. In addition, when the sensor 43 is not a sensor that detects the presence or absence of the backward movement, such as a limit switch, but a sensor that continuously detects a physical quantity related to the backward movement, such as a position sensor or a pressure sensor, step ST7 may determine whether or not the detected quantity (for example, the backward movement quantity in the case of the position sensor) exceeds a predetermined threshold value.

In step ST8, the control device 5 controls the hydraulic device 49 to advance the pressurizing member 41. That is, instead of the reservoir 61 of the low-pressure circuit 59L, the control device 5 controls the control valve 63 of the low-pressure circuit 59L and the control valve 63 of the high-pressure circuit 59H to supply the working fluid from the reservoir 61 of the high-pressure circuit 59H to the head-side chamber 53H. This locally pressurizes (in other aspects, pressurizes).

In step ST9, the control device 5 determines whether or not the pressure applied to the melt by the pressurizing member 41 reaches the target value, that is, the pressure P2. Then, the control device 5 stands by (continues the advance of the pressurizing member 41) in the negative determination, and proceeds to step ST10 in the affirmative determination.

In step ST10, the control device 5 stops the advance of the pressing member 41. For example, the control device 5 stops supplying the working fluid to the head side chamber 53 h. Thus, pressure maintaining is performed. At this time, in order not to retract the pressurizing member 41 due to the pressure from the melt, the discharge of the working fluid from the head side chamber 53h may be inhibited. Alternatively, the working fluid may be supplied to the head side chamber 53h in an amount corresponding to the leakage of the working fluid.

Although not particularly shown, after that, if a predetermined condition (for example, a predetermined time period has elapsed) concerning solidification of the melt is satisfied, the control device 5 ends the holding pressure. For example, the control device 5 connects the head side chamber 53h to the tank 69 or the reservoir 61 of the low pressure circuit 59L. The control device 5 performs control related to the mold opening, the retraction of the plunger 21, and the like. Thereafter, the control device 5 may return to step ST2 to repeat the injection cycle (molding cycle) until a predetermined end condition is satisfied.

In fig. 8, as indicated by an arrow connecting step ST4 and step ST7, an affirmative determination is made in step ST4 as a precondition for executing step ST 7. In another aspect, the control device 5 may control the driving portion 45A to start the advance of the pressurizing member 41, on the condition that the pressure applied to the melt by the plunger 21 reaches a predetermined pressure (in the example of fig. 8, the pressure P1). This effect will be described in the summary of the first embodiment described later.

In the manner in which the plurality of pressing members 41 and the plurality of pressing cylinders 47 are provided, steps ST7 to S10 may be performed independently of each other for each pressing cylinder 47. Thus, the plurality of pressing members 41 disposed at different positions from each other can be controlled at appropriate timings.

In step ST1, the target pressure P2, which is the target pressure for local pressurization, may be set by the user, or may be set by the control device 5 based on the target value of the casting pressure or the like. In the former case, the control device 5 may warn the user by a display device and/or an acoustic device when the input pressure P2 is smaller than the target value of the casting pressure or the plastic deformation resistance and/or exceeds the burr generation limit curve, or may invalidate the input of such pressure P2. In the case where the control device 5 sets the pressure P2, the control device 5 may set the pressure P2 so that the pressure P2 becomes equal to or higher than the target value of the casting pressure and/or equal to or higher than the plastic deformation resistance and/or equal to or lower than the limit curve of the burr generation.

(Summary of the first embodiment)

As described above, the local pressurizing device 2A of the first embodiment includes: a pressing member 41 having a tip exposed to the inside (space 107) of the mold (mold 101), and a driving portion 45A for applying a forward force to the pressing member 41. When the molding material (e.g., molten metal) reaches the position of the pressurizing member 41, the pressurizing member 41 is positioned at an initial position (e.g., a forward limit) forward of the backward limit, and is pushed by the molten metal to be retracted from the initial position.

In another aspect, the molding machine (die casting machine with die DC or die casting machine 1) of the first embodiment includes: the pressurizing device 2A, the mold clamping device 7 for opening and closing the mold 101, and the injection device 9 for injecting the melt into the space 107.

In still another aspect, the molding method of the first embodiment includes an injection step (see step ST 3) and a partial pressurization step (see step ST 8). The injection step injects the melt into the space 107. The partial pressurizing step advances the pressurizing member 41 with its tip exposed to the space 107, thereby pressurizing the melt in the space 107. When the melt reaches the position of the pressurizing member 41, the pressurizing member 41 is positioned at an initial position forward of the retraction limit, and is pushed by the melt to retract from the initial position.

Therefore, before the description of the first embodiment, various effects can be obtained as described with reference to fig. 1 (a) to 3 (b). For example, the impact pressure can be absorbed by the retreating of the pressing member 41, the possibility of occurrence of burrs can be reduced, and the advancing timing of the pressing member 41 can be optimized, reducing the possibility of occurrence of shrinkage cavities.

The driving portion 45A may position the pressing member 41 at the initial position in a state where the pressing member 41 is applied with an initial forward force when the molding material reaches the position of the pressing member 41. The initial force may be smaller than the force applied to the pressing member 41 when the maximum pressure (pressure P1) in the injection process in which the injection plunger (plunger 21) is applied to the molding material is applied to the pressing member 41 from the front.

In this case, for example, the melt may retract the pressurizing member 41 against the initial force. During this process, the energy possessed by the melt is consumed. Therefore, the impact pressure is effectively absorbed.

The pressurizing device 2A may have: a sensor 43 that detects the retreat of the pressing member 41; and a control device 5 that controls the driving unit 45A so that the advance of the pressing member 41 is started at a timing when the backward movement of the pressing member 41 is detected by the sensor 43.

In this case, for example, an effect of optimizing the advancing timing of the pressing member 41 can be obtained. The timing at which the retraction of the pressing member 41 is detected is different from the example of fig. 8, and is not limited to the timing just detected, and may be a timing at which a predetermined time has elapsed from the detection timing.

The control device 5 may control the driving unit 45A to start the advance of the pressing member 41 (see an arrow from step ST4 to step ST7 in fig. 8) on the condition that the pressure applied to the molding material by the plunger 21 reaches a predetermined pressure (in the example of fig. 8, the pressure P1).

In this case, for example, the possibility that the pressurizing member 41 starts to advance when the melt filling is not completed is reduced. As a result, for example, the sensitivity of detecting the backward movement of the pressing member 41 (step ST 7) can be improved. For example, the amount of retraction up to the position where the limit switch is turned on may be reduced, or the amount of retraction (threshold value) when the control device 5 determines that the pressure member 41 has retracted based on the detection value of the position sensor may be reduced, or the amount of pressure increase (threshold value) when the control device 5 determines that the pressure member 41 has retracted based on the detection value of the pressure sensor 71H may be reduced. This improvement in sensitivity is effective, for example, when injection pressure is difficult to be transmitted to the position of the pressurizing member 41 as solidification of the melt proceeds.

The pressing member 41 may be configured to apply a pressure equal to or higher than at least one of the casting pressure set by the control device 5 and the plastic deformation resistance of the molding material after being retracted from the initial position.

In this case, for example, the pressure of the molding material is easily set to an appropriate level not only locally but also as a whole. As a result, for example, as described above, when the pressurization is performed by local pressurization instead of by injection pressure, the quality of the product can be improved.

The pressing member 41 may apply a pressure to the molding material that is equal to or lower than the limit curve of the burr determined by the control device 5 after the pressing member is retracted from the initial position.

In this case, for example, the possibility of occurrence of burrs around the pressing member 41 is reduced. In other aspects, the quality can be improved by applying as much local pressure as possible to the melt while reducing the possibility of flash generation.

The driving section 45 may have: a hydraulic cylinder (a pressurizing cylinder 47), a reservoir 61, a back pressure eliminating cylinder 65, and a servo valve (a control valve 63). The pressure cylinder 47 is coupled to the pressure member 41. The reservoir 61 is connected to a first cylinder chamber (head side chamber 53 h) of the pressure cylinder 47 to which the working fluid is supplied when the pressure member 41 advances. The back pressure cancellation cylinder 65 is connected to a second cylinder chamber (rod side chamber 53 r) of the pressure cylinder 47 that discharges the working fluid when the pressure member 41 advances. The control valve 63 controls the flow from the reservoir 61 to the head side chamber 53 h.

In this case, for example, a high pressure can be applied to the head side chamber 53h, and the back pressure of the rod side chamber 53r can be quickly eliminated, so that the responsiveness of the pressurizing member 41 improves. As a result, for example, in combination with the effect of appropriately detecting the arrival of the melt by the sensor 43, the pressurizing member 41 can be advanced at an appropriate timing. Further, since the flow rate can be controlled by the control valve 63 serving as a servo valve, the possibility of excessive advance of the pressurizing member 41 is reduced by using the accumulator 61 and the back pressure eliminating cylinder 65.

When D is the diameter of the tip of the pressing member 41 and D is the diameter of the tip of the plunger 21, D/D may be 0.2 or more and 0.5 or less.

In this case, for example, by setting D/D to 0.5 or less, the pressure applied to the melt by the pressurizing member 41 can be made relatively large with respect to the driving force generated by the driving portion 45A that drives the pressurizing member 41, and the burden on the driving portion 45A can be reduced. Further, for example, by setting D/D to 0.2 or more, a relatively large volume of the press-molding material can be ensured, and the effect of local pressurization can be improved.

(Second embodiment)

Fig. 9 (a) and 9 (B) are cross-sectional views showing the structure of the pressurizing device 2B according to the second embodiment. Fig. 9 (a) corresponds to fig. 1 (b), and shows a state in which the molten metal does not reach the position of the pressurizing member 41, and the pressurizing member 41 is located at the initial position (forward limit). Fig. 9 (b) corresponds to fig. 2 (b), and shows a state in which the molten metal reaches the position of the pressurizing member 41 and the pressurizing member 41 is retracted.

In the pressurizing device 2B, an elastic member 45B is used as the driving portion 45. Before the melt reaches the pressurizing member, the pressurizing member 41 is pushed forward (space 107 side) by the restoring force of the elastic member 45B, and is positioned at the forward limit. When the pressing member 41 is positioned at the forward limit, the elastic member 45B may be in a state where a restoring force is generated (a state where deformation remains), or may be in a state where substantially no restoring force is generated.

Then, when the melt 109 reaches the position of the pressurizing member 41, the pressurizing member 41 retreats. The elastic member 45B increases the restoring force with the retraction of the pressing member 41. The pressurizing member 41 is stopped at a position where the force received from the melt and the restoring force of the elastic member 45B are balanced (here, influence of friction force and the like is ignored). Unlike the above, the pressing member 41 may be stopped by abutting against a stopper, not shown, defining the retraction limit.

The specific structure of the elastic member 45B may be appropriately constituted. In the illustrated example, the elastic member 45B is formed of a coil-shaped spring, and has a tip end in contact with the pressing member 41 and a rear end in contact with the stent 103 (or a member fixed to the stent 103). Then, the elastic member 45B generates a restoring force by compression deformation. Other specific examples of the elastic member 45B include one or more leaf springs (for example, laminated belleville springs) (the same applies to other embodiments described later). In addition, the pressurizing device 2B does not include a driving portion such as the pressurizing cylinder 47 for actively generating a driving force for the sake of care.

In the present embodiment, the pressurizing device 2B also has: the pressing member 41 having a tip exposed to the inside (space 107) of the mold (mold 101), and a driving portion (elastic member 45B) for applying a forward force to the pressing member 41. When the molding material (melt 109) reaches the position of the pressing member 41, the pressing member 41 is pushed by the melt 109 to retract from the forward limit at the initial position (forward limit) located forward of the backward limit.

Therefore, at least a part of the effects described before the description of the first embodiment is exhibited. For example, the impact pressure can be absorbed. The elastic member 45B absorbs the impact pressure, so that the pressurizing member 41 can apply a pressure higher than the pressure of the melt after the impact pressure converges. In this way, the effect of local pressurization can be obtained.

As shown in the present embodiment, the driving unit 45 may include an elastic member 45B that applies a restoring force to the pressing member 41 in the forward direction.

In this case, for example, the impact pressure can be sufficiently absorbed by the elastic deformation of the elastic member 45B, as compared with the manner in which the impact pressure is absorbed by the fluid compression (this manner is also included in the technique according to the present invention). In addition, since the necessity of using a fluid is reduced, a member such as a seal can be omitted. Further, the absorption of the impact pressure locally pressurizes the melt after the convergence of the impact pressure, so that energy can be saved.

(Third embodiment)

Fig. 10 is a cross-sectional view showing the structure of a pressurizing device 2C according to the third embodiment, and corresponds to fig. 1 (b). The drawing shows a state in which the melt does not reach the position of the pressurizing member 41, and the pressurizing member 41 is located at the initial position (forward limit).

In short, the driving portion 45C of the pressurizing device 2C is a combination of the pressurizing cylinder 47 of the first embodiment and the elastic member 45B of the second embodiment. Specifically, the elastic member 45B and the pressure cylinder 47 are provided so as to be capable of applying a force to the pressure member 41 in parallel. In addition, "juxtaposed" herein refers to the application of force, not to the positional relationship.

Specifically, in the illustrated example, the piston rod 57 of the pressure cylinder 47 is coupled to the pressure member 41 as in the first embodiment. The elastic member 45B is constituted by a coil-shaped spring, and is arranged concentrically with respect to the piston rod 57. The elastic member 45B has a tip end in contact with the pressing member 41 and a rear end in contact with the stent 103 (or a member fixed to the stent 103) and generates a restoring force by compression deformation, as in the second embodiment.

Although not particularly shown, the driving unit 45C includes a hydraulic device that supplies the hydraulic fluid or the like to the pressure cylinder 47. The hydraulic device has the low pressure circuit 59L removed from the hydraulic device 49 shown in fig. 5 and 6. As described below, this is because the elastic member 45B may be responsible for replacing the low-pressure circuit 59L.

At the time of injection (time t0 to t2 in fig. 7), the hydraulic device connects the rod side chamber 53r and the head side chamber 53h to the tank 69, for example. Therefore, the pressing member 41 is pressed forward by the restoring force of the elastic member 45B, and is positioned at the forward limit (initial position). When the melt reaches the position of the pressurizing member 41, the pressurizing member 41 retreats with the deformation of the elastic member 45B, as in the second embodiment. At this time, the impact pressure can also be absorbed. When the pressing member 41 moves backward, the high-pressure circuit 59H and the pressing cylinder 47 start the movement of the pressing member 41, and the partial pressing is performed (see steps ST7 to ST10 in fig. 8) similarly to the first embodiment.

When the pressure member 41 is moved forward by the elastic member 45B before the partial pressure is applied, as in the first embodiment, the discharge of the working fluid from the rod side chamber 53r can be inhibited by a pilot check valve or the like, and the pressure member 41 can be stopped before the pressure member 41 reaches the forward limit. That is, the initial position may be a position other than the forward limit.

As described above, in the present embodiment, the local pressurizing device 2C also has: a pressing member 41 having a tip exposed to the inside (space 107) of the mold (mold 101), and a driving portion 45C for applying a forward force to the pressing member 41. When the molding material (e.g., molten metal) reaches the position of the pressurizing member 41, the pressurizing member 41 is positioned at an initial position (e.g., a forward limit) forward of the backward limit, and is pushed by the molten metal to be retracted from the initial position.

Therefore, the effects described earlier in the description of the first embodiment can be obtained. For example, the impact pressure can be absorbed, and the start time of the local pressurization can be optimized.

As shown in the present embodiment, the driving unit 45C may include: a hydraulic cylinder (a pressure cylinder 47) for applying a driving force to the pressure member 41, and an elastic member 45B for applying a restoring force to the pressure member 41 in the forward direction. The pressure cylinder 47 and the elastic member 45B may be provided so as to be capable of applying a force to the pressure member 41 in parallel with each other.

In this case, for example, the pressing member 41 is positioned at the initial position by the elastic member 45B, and the forward force can be applied to the pressing member 41, so that the low-pressure circuit 59L of the first embodiment is not required. As a result, the hydraulic device is simplified.

(Fourth embodiment)

Fig. 11 is a cross-sectional view showing the structure of a pressurizing device 2D according to the fourth embodiment, and corresponds to fig. 1 (b). The drawing shows a state in which the melt does not reach the position of the pressurizing member 41 and the pressurizing member 41 is positioned at the initial position.

In short, the driving unit 45D of the pressurizing device 2D is formed by combining the pressurizing cylinder 47 of the first embodiment and the elastic member 45B of the second embodiment, as in the third embodiment. Then, as in the third embodiment, before the melt reaches the pressurizing member 41, the elastic member 45B presses the pressurizing member 41 forward instead of the low-pressure circuit 59L, so that the pressurizing member 41 is positioned at the initial position (for example, the forward limit). However, in the third embodiment, the elastic member 45B and the pressure cylinder 47 are provided so as to be able to apply force to the pressure member 41 in parallel with each other, whereas in the present embodiment, the elastic member 45B and the pressure cylinder 47 are provided so as to be able to apply force to the pressure member 41 in series with each other

Specifically, in the illustrated example, the piston rod 57 of the pressure cylinder 47 is coupled to the pressure member 41 as in the first embodiment. The elastic member 45B is formed of a coil-shaped spring, and has a front end abutting against the rear end of the cylinder member 53 and a rear end abutting against the fixed die 103 (or a member fixed to the fixed die 103). Then, the elastic member 45B generates a restoring force by compression deformation. In addition, as a mode different from the illustrated example, for example, a mode in which the cylinder member 53 is fixed to the fixed die 103 and the elastic member 45B is interposed between the piston rod 57 and the pressure member 41 is exemplified.

Although not particularly shown, the driving unit 45D includes a hydraulic device that supplies the hydraulic fluid or the like to the pressure cylinder 47. The hydraulic device is similar to the third embodiment in that the low-pressure circuit 59L is omitted from the hydraulic device 49 shown in fig. 5 and 6.

At the time of injection (time t0 to t2 in fig. 7), the hydraulic device positions the piston 55 at an appropriate position (e.g., a retraction limit) with respect to the cylinder member 53, for example. The rod side chamber 53r and the head side chamber 53h may prohibit the inflow and outflow of the working fluid, for example. Then, the pressing member 41 is pushed forward together with the pressing cylinder 47 by the restoring force of the elastic member 45B, and is positioned at the forward limit position. When the melt reaches the position of the pressurizing member 41, the pressurizing member 41 retreats together with the pressurizing cylinder 47 along with the deformation of the elastic member 45B. At this time, the impact pressure can also be absorbed. When the pressing member 41 moves backward, the high-pressure circuit 59H and the pressing cylinder 47 start the movement of the pressing member 41, and the partial pressing is performed (see steps ST7 to ST 10) similarly to the first embodiment. Although not particularly shown, a stopper may be provided to define the retraction limit of the cylinder member 53 with respect to the fixed die 103.

As described above, fig. 11 shows a state in which the pressing member 41 is located at the initial position, for example. In the illustrated example, the pressing cylinder 47 can further advance the pressing member 41 from the initial position. Therefore, fig. 11 shows the initial position of the pressing member 41 that is not the forward limit. When the local pressurization is performed, the pressurization member 41 may be controlled to advance forward of the initial position, or such control may not be performed. Further, unlike the illustrated example, when the pressing member 41 is positioned at the illustrated position, the illustrated position is set to the forward limit by, for example, bringing the pressing member 41 (or a member fixed to the pressing member 41) into contact with a stopper provided to the stent 103 (or a member fixed to the stent 103)

As described above, in the present embodiment, the local pressurizing device 2D also has: a pressing member 41 having a tip exposed to the inside (space 107) of the mold (mold 101), and a driving portion 45D for applying a forward force to the pressing member 41. When the molding material (e.g., molten metal) reaches the position of the pressurizing member 41, the pressurizing member 41 is positioned at an initial position (e.g., a forward limit) forward of the backward limit, and is pushed by the molten metal to be retracted from the initial position.

As shown in the present embodiment, the driving unit 45D may include a hydraulic cylinder (a pressure cylinder 47) that applies a driving force to the pressure member 41, and an elastic member 45B that applies a restoring force to the pressure member 41 in the forward direction. The pressure cylinder 47 and the elastic member 45B may be provided so as to be capable of applying a force to the pressure member 41 in series with each other.

In this case, for example, as in the third embodiment, the pressurizing member 41 can be positioned at the initial position by the elastic member 45B, so that the low-pressure circuit 59L of the first embodiment is not required. As a result, the hydraulic device is simplified.

(Fifth embodiment)

Fig. 12 is a schematic view showing the structure of a belt molding machine DCE of the fifth embodiment.

The pressurizing device 2E (driving unit 45E) of the present embodiment is configured to drive the pressurizing member 41 by the pressurizing cylinder 47, as in the first embodiment. However, the present embodiment differs from the first embodiment in the manner of supplying the hydraulic fluid to the pressure cylinder 47. Specifically, in the hydraulic device 49E of the present embodiment, the head side chamber 53h of the pressure cylinder 47 is communicated with the head side chamber 31h of the injection cylinder 27E through the communication passage 83, and the same pressure as the pressure applied to the head side chamber 31h is supplied to the head side chamber 53h. In more detail, for example, as follows.

(Structure of injection device and pressurizing device)

In the present embodiment, the driving portion 23E that drives the plunger 21 includes an injection cylinder 27E. The driving unit 23E is configured to apply a higher pressure to the head side chamber 31h than the pressure applied to the head side chamber 31h in the narrow injection process (time t0 to time t2 in fig. 7) to pressurize the same. Examples of such a driving unit 23E include: a method having a supercharged injection cylinder (example shown in the figure), and a method having a reservoir for only supercharging during injection and supercharging. The driving unit 23E may be a hybrid type in which an injection cylinder and a motor are used in combination. Hereinafter, an example (a supercharged injection cylinder 27E) will be described as an example.

The injection cylinder 27E has, like the injection cylinder 27 shown in fig. 1 (a),: a cylinder member 31E, a piston 33, and a piston rod 37. But the cylinder member 31E has: the small-diameter cylinder portion 31x and the large-diameter cylinder portion 31y communicating with the rear side (right side in fig. 12) of the small-diameter cylinder portion 31x and having a larger diameter than the small-diameter cylinder portion 31x, the small-diameter cylinder portion 31x corresponds to the cylinder member 31 in fig. 1 (a). The injection cylinder 27E has a pressurizing piston 35 behind the piston 33.

The booster piston 35 has: a small diameter portion 35x sliding on the small diameter cylinder portion 31x, and a large diameter portion 35y sliding on the large diameter cylinder portion 31 y. The large-diameter portion 35y divides the large-diameter cylinder portion 31y into a front side chamber 31a and a rear side chamber 31b. The area of the pressurizing piston 35 receiving the pressure in the front (head side chamber 31 h) is smaller than the area receiving the pressure in the rear (rear side chamber 31 b). Therefore, the pressurizing piston 35 can apply a higher pressure to the head side chamber 31h than to the rear side chamber 31b in a state where the pressure in the front side chamber 31a is released.

The ratio of the area of the pressure received from the front by the pressurizing member 41 to the area of the pressure received from the head side chamber 53h by the piston 55 in the pressurizing cylinder 47 is substantially equal to the ratio of the area of the pressure received from the front by the plunger 21 to the area of the pressure received from the head side chamber 31h by the piston 33 in the injection cylinder 27E. Therefore, for example, if the pressures equal to each other are applied to the head side chamber 53h and the head side chamber 31h, the pressure member 41 and the plunger 21 can apply the pressures equal to each other to the melt.

In addition, as the supercharged injection cylinder, for example, a structure in which a cylinder member in which the piston 33 slides and a cylinder member in which the supercharged piston 35 slides are separated may be cited in addition to the illustrated example. In other words, in the supercharged cylinder, the area of the pressurizing piston 35 receiving the pressure of the head side chamber 31h may be smaller than the area of the pressure received from the opposite side. For the sake of caution, the hydraulic device 49E does not include the low-pressure circuit 59L and the high-pressure circuit 59H (in other words, the reservoir 61 dedicated to the pressurizing device 2E). The pressurizing device 2E does not have the sensor 43 for detecting the backward movement of the pressurizing member 41, for example.

(Operation of injection device and pressurizing device)

In the injection step (time t0 to t2 in fig. 7), the control device 5 opens the valve 81A to supply the working fluid from the reservoir 79 to the head side chamber 31h of the injection cylinder 27E. Switching of the injection speed is achieved by means of a meter-out circuit (in the example shown, reference sign omitted) and/or a meter-in circuit.

The head side chamber 53h of the pressurizing cylinder 47 communicates with the head side chamber 31h at a proper timing (for example, at the start of injection) before completion of the melt filling. Therefore, the pressure of the reservoir 79 is also applied to the head side chamber 53h. Therefore, the pressing member 41 is pressed forward and is positioned at the initial position (for example, the forward limit).

When the molten metal is substantially filled in the space 107 of the mold 101, the pressure of the molten metal reaching the position of the pressurizing member 41 increases. As described above, the pressurizing member 41 can apply the same pressure as the plunger 21 to the melt. Therefore, for example, when an impact pressure is generated, the pressing member 41 retreats.

When the predetermined pressurizing condition is satisfied, the control device 5 opens the valve 81B and supplies the working fluid from the reservoir 79 to the rear side chamber 31B of the injection cylinder 27E. As described above, the pressurizing piston 35 applies a pressure higher than the pressure of the rear side chamber 31b to the head side chamber 31 h. The valve 81A is closed automatically or by the control device 5. As a result, the plunger 21 increases the pressure applied to the melt (time t2 to time t in fig. 7). Unlike fig. 7, the injection pressure (line LP) rises in a manner approaching the casting pressure (line LC).

At this time, communication between the head side chamber 53h and the head side chamber 31h continues. Therefore, the pressure of the pressurized head side chamber 31h is also applied to the head side chamber 53h. As a result, the pressurizing member 41 can locally pressurize as in the pressurizing of the plunger 21.

In order to perform the above-described operations appropriately, various valves and pressure relief cylinders (each of which is omitted) may be provided in the communication path 83 appropriately. Further, since the pressure of the melt and the like are different between the position of the plunger 21 and the position of the pressurizing member 41 as the solidification of the melt proceeds, the size may be appropriately set so that the magnitude and/or timing of the pressure applied to the melt by the plunger and the pressurizing member are different from each other, or the control of the communication passage 83 may be performed.

As described above, in the present embodiment, the local pressurizing device 2E also has: a pressing member 41 having a tip exposed to the inside (space 107) of the mold (mold 101), and a driving portion 45E for applying a forward force to the pressing member 41. When the molding material (e.g., molten metal) reaches the position of the pressurizing member 41, the pressurizing member 41 is positioned at an initial position (e.g., a forward limit) forward of the backward limit, and is pushed by the molten metal to be retracted from the initial position.

This can obtain the effects described in the description of the first embodiment. For example, the impact pressure can be absorbed.

As shown in the present embodiment, the driving unit 45E may have a hydraulic cylinder (a pressure cylinder 47) connected to the pressure member 41. The first cylinder chamber (head side chamber 53 h) of the pressure cylinder 47 to which the working fluid is supplied when the pressure member 41 advances may communicate with the head side chamber 31h of the injection cylinder 27E that drives the injection plunger (plunger 21) to which the working fluid is supplied when the plunger 21 advances.

In this case, for example, at least one (in the illustrated example, both) of the driving force for positioning the pressurizing member 41 at the initial position before the melt reaches the position of the pressurizing member 41 and the driving force for locally pressurizing by advancing the pressurizing member 41 after the pressurizing member 41 is retracted can be obtained by supplying the working liquid from the liquid reservoir 79 for injection. In addition, for example, in the system in which the pressure of the head side chamber 31h is increased to start the pressurization by the plunger 21, the start timing of the local pressurization can be made to follow the start timing of the pressurization. As a result, the timing of the local pressurization is optimized.

Further, unlike the illustrated example, the pressure cylinder 47 may be supplied with the working fluid from the low-pressure circuit 59L in a state of being isolated from the injection cylinder 27E and may be located at the initial position, and then may be supplied with the pressure of the head side chamber 31h after the pressurization at the time of the local pressurization. Conversely, the pressure cylinder 47 may be supplied with the working fluid from the reservoir 79 that supplies the working fluid to the head side chamber 31H to be positioned at the initial position, and then may be supplied with the working fluid from the high pressure circuit 59H when the local pressurization is performed.

(Other examples of the position of the pressing part)

Fig. 13 shows an example in which the position of the pressing member 41 is different from the example shown above.

In the description of the first embodiment, the case where the pressurizing member 41 can pressurize the melt in any portion (the product portion 107a, the overflow portion 107b, the runner 107e, and the like) of the space 107 is described. In the example of fig. 13, the pressurizing member 41 is configured to pressurize the melt of the runner 107 e.

Specifically, in the illustrated example, the runner 107e is provided with its flow direction intersecting (e.g., orthogonal to) the sleeve 19. In other points of view, in the illustrated example, the flow direction of the runner 107e is the up-down direction. A sleeve 19 is connected to a lower side surface of the runner 107 e. The upper portion of the runner 107e communicates with the product portion 107a via a gate (symbol omitted).

The pressurizing member 41 is disposed on the opposite side of the sprue 107e from the product portion 107a, for example, and is provided so as to be movable in the flow direction of the sprue 107 e. The position of the pressurizing member 41 shown in fig. 13 is, for example, an initial position before the melt reaches the pressurizing member 41. The initial position may or may not be the forward limit of the pressing member 41. In other words, the pressurizing member 41 may not be able to intrude into the runner 107e or may be able to intrude. Further, unlike the illustrated example, the pressurizing member 41 may be provided so as to be movable in a direction different from the flow direction of the runner 107 e.

The pressurizing member 41 for pressurizing the runner 107e may be combined with any of the driving units 45 of the various embodiments. For example, the driving unit 45D (fig. 11) of the fourth embodiment may be used as the driving unit 45. In this case, the illustrated initial position is located at the forward limit of the cylinder member 53 with respect to the mold 101, or may be located at a position (for example, a backward limit) behind the forward limit of the piston 55 with respect to the cylinder member 53, as in fig. 11. In the partial pressurization, the pressurizing member 41 may be advanced upward from the illustrated position.

In the above embodiment, the mold 101 is an example of a mold. The die casting machine DC or DCE and the die casting machine 1 are examples of molding machines. The melt 109 is an example of a molding material. The plunger 21 is an example of an injection plunger. The pressure cylinder 47 is an example of a hydraulic cylinder. The head side chamber 53h is an example of the first cylinder chamber. The rod side chamber 53r is an example of the second cylinder chamber. The control valve 63 is an example of a servo valve.

The present invention is not limited to the above embodiments and modifications, and can be implemented in various ways.

The molding machine is not limited to a die casting machine. For example, the molding machine may be another metal molding machine, an injection molding machine for molding a resin, or a molding machine for molding a wood powder mixed with a material such as a thermoplastic resin. The molding machine is not limited to the transverse mold-clamping transverse injection, and may be, for example, longitudinal mold-clamping longitudinal injection, longitudinal mold-clamping transverse injection, or transverse mold-clamping longitudinal injection. The die casting machine is not limited to the cold chamber die casting machine, but may be, for example, a hot chamber die casting machine. The working fluid is not limited to oil, and may be water, for example.

Injection is not limited to include low-speed injection and high-speed injection, and for example, laminar filling may be performed at a low speed. The pressing member for locally pressing may also be used as an extrusion pin for extruding a molded article formed by solidifying a molding material from a mold. As described in the description of the present embodiment, the driving unit may be an electric driving mechanism. For example, a linear motor (including a voice coil motor) may be provided instead of the pressure cylinder.

The structures of the plurality of embodiments may be appropriately combined. For example, in the embodiment in which the plurality of pressing members 41 are provided, the configuration of the driving portions 45 different from each other may be applied to one die casting machine.

Symbol description

DC: belt molding machine (molding machine), 1: die casting machine (forming machine), 2: local pressurizing device, 5: control device, 9: injection device, 41: pressurizing member, 43: sensor, 45: drive unit, 47: a pressurizing cylinder, 101: metal mold (mold), 107: space (inner of mould)

Claims

1. A local pressurizing device, comprising:

A pressing member having a tip exposed to the inside of the mold;

a driving part for applying a forward force to the pressing member,

The pressing member is positioned at an initial position forward of a retraction limit when the molding material reaches the position of the pressing member, and is pushed by the molding material to retract from the initial position.

2. The local pressurizing device as claimed in claim 1, wherein,

When the molding material reaches the position of the pressing member, the driving unit causes the pressing member to be positioned at the initial position in a state where an initial forward force is applied to the pressing member,

The initial force is smaller than a force applied to the pressing member when a maximum pressure in an injection process of an injection plunger applied to the molding material is assumed to be applied to the pressing member from the front.

3. The local pressurizing device according to claim 1 or 2, further comprising:

A sensor that detects the retreat of the pressing member;

And a control device that controls the driving unit to start advancing the pressing member when the sensor detects the pressing member to retract.

4. A localized pressurizing device as set forth in claim 3, wherein,

The control device controls the driving unit to start the advancement of the pressing member, on the condition that the pressure applied to the molding material by the injection plunger reaches a predetermined pressure.

5. The local pressurizing device as claimed in any one of claims 1 to 4, wherein,

After the pressing member is retracted from the initial position, a pressure equal to or higher than at least one of a casting pressure set by a control device and a plastic deformation resistance of the molding material is applied to the molding material.

6. The local pressurizing device according to any one of claims 1 to 5, wherein,

After the pressing member is retracted from the initial position, a pressure equal to or lower than a limit curve is applied to the molding material by the flash determined by the control device.

7. The local pressurizing device as claimed in any one of claims 1 to 6, wherein,

The driving unit includes:

a hydraulic cylinder connected to the pressurizing member;

a reservoir connected to a first cylinder chamber of the hydraulic cylinder to which the working fluid is supplied when the pressurizing member advances;

a back pressure cancellation cylinder connected to a second cylinder chamber of the hydraulic cylinder that discharges the working fluid when the pressurizing member advances;

A servo valve controlling flow from the reservoir to the first cylinder chamber.

8. The local pressurizing device according to any one of claims 1 to 7, wherein,

The driving section includes an elastic member that applies a restoring force to the pressing member in a forward direction.

9. The local pressurizing device as claimed in any one of claims 1 to 6, wherein,

The driving unit includes:

a hydraulic cylinder that applies a driving force to the pressurizing member;

an elastic member that applies a restoring force to the pressing member in the forward direction,

The hydraulic cylinder and the elastic member are provided so as to be capable of applying a force to the pressurizing members in parallel with each other.

10. The local pressurizing device as claimed in any one of claims 1 to 6, wherein,

The driving unit includes:

a hydraulic cylinder that applies a driving force to the pressurizing member;

The hydraulic cylinder and the elastic member are provided so as to be capable of applying a force to the pressurizing member in series with each other.

11. The local pressurizing device as claimed in any one of claims 1 to 6, wherein,

The driving part is provided with a hydraulic cylinder connected with the pressurizing component,

The first cylinder chamber of the hydraulic cylinder to which the working fluid is supplied when the pressurizing member advances communicates with the head side chamber of the injection cylinder that drives the injection plunger to which the working fluid is supplied when the injection plunger advances.

12. The local pressurizing device according to any one of claims 1 to 11, wherein,

When D is the diameter of the tip of the pressurizing member and D is the diameter of the tip of the injection plunger, D/D is 0.2 to 0.5.

13. A molding machine is provided with:

the local pressurizing device according to any one of claims 1 to 12;

a mold clamping device for opening and closing the mold and clamping the mold;

An injection device that injects the molding material into the mold.

14. A molding method comprises:

An injection step of injecting a molding material into the inside of the mold,

A partial pressurizing step of advancing a pressurizing member having a tip exposed to the inside of the mold to pressurize the molding material in the inside of the mold,