JP2002292454A - Pressure casting method - Google Patents

Abstract

(57) [Problem] To provide a pressure casting method for efficiently producing an automobile disk wheel by a pressure casting method using a vertical die casting machine and a degassing device for a mold. SOLUTION: A molten metal is filled into a mold cavity by an injection device from a gate portion provided at a lower portion of a mold, and a pressure pin provided at a position facing the gate portion is inserted into the molten metal. In the pressure casting method of pressurizing the molten metal in the mold cavity, after the molten metal is solidified and the plunger tip of the injection device is retracted, the pressure pin is advanced again to solidify the molten metal remaining in the gate portion. Stick out things.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure casting method for providing a feeder effect by a pressure pin, and more particularly to a pressure casting method in which a molten metal solidified at a gate portion of a mold cavity is projected by the pressure pin. It is about.

[0002]

2. Description of the Related Art In order to cast a high-quality aluminum disk foil without entrainment of gas, a pressure casting method using a pressure pin using a vertical die casting machine and a degassing device for a mold has been adopted. In this pressure casting method, a solidified molten metal which does not become a product necessarily remains in the annular runner portion on the outer periphery of the rim and the gate portion below the mold provided for degassing. In order to improve the productivity of the disk foil, it is necessary to process these solidified slurries efficiently and without damaging the product.

As a prior art which has solved these problems, there is Japanese Patent Publication No. 2-40415. This publication discloses a method of extruding a solid product in an annular runner as a method of extruding a molten product in an annular runner by a pressing member so as not to be pushed out of the annular runner, and only casting a product in a mold cavity to the annular runner. Extruding while separating from the solidified material in the melt,
Next, it is described that after a desired time has elapsed, the pressing state of the molten solidified material in the annular runner by the pressing member is released, and the molten solidified material in the annular runner is extruded. On the other hand, as a method for extruding the solidified molten metal remaining at the gate located at the lower part of the mold, as shown in FIG. 5 (f) of the above-mentioned publication, a separate extruder is moved between the two molds with the mold opened. It describes that the molten metal solidified material (hereinafter, also referred to as biscuit) remaining at the gate portion is extruded by advancing a piston rod of the extruder.

[0004]

In the above-mentioned conventional pressure casting method, a separately disposed extruder is moved between the opened dies and the piston rod of the extruder is advanced. Extruded the biscuit at the gate. Therefore, the casting apparatus is complicated and the molding cycle is long. There has been a demand for a biscuit processing method that can solve these problems. SUMMARY OF THE INVENTION It is an object of the present invention to provide a pressure casting method for efficiently producing a disk foil for an automobile by a pressure casting method using a vertical die casting machine and a degassing device for a mold.

[0005]

In order to solve the above-mentioned problems, in the present invention, molten metal is filled into a mold cavity by an injection device from a gate portion provided at a lower portion of the mold. In a pressure casting method in which a pressure pin disposed at a position facing a gate portion is inserted into the molten metal to press the molten metal in the mold cavity, the molten metal solidifies and the plunger tip of the injection device is retracted. After that, the pressure pin was advanced again to eject the solidified molten metal remaining in the gate portion.

[0006]

Embodiments of the present invention will be described below in detail. First, the structure of a pressure casting apparatus used in the present invention will be described with reference to FIG. In FIG. 1, a mold opening / closing unit 1 has a mounting plate 2 fixed on a rotary table (not shown), and a piston which moves up and down by hydraulic pressure of a pair of mold opening / closing cylinders 3 erected on both right and left sides of the mounting plate. A horizontal plate-shaped top plate 5 is fixedly supported at the working end of the rod 4. The top plate and the upper mold 1 described later are moved by the reciprocation of the piston rod 4.
6 and the like are guided by four guide rods (not shown) to ascend and descend, so that mold opening and mold matching are performed. A lower mold sleeve support plate 7 generally indicated by reference numeral 6 is fixed to the mounting plate 2. The lower mold 6 is formed of a sleeve support plate and an annular shape fixed to the sleeve support plate with a plurality of bolts. An annular die holder 11 supported by a core stopper ring 9, a plurality of guide pins 10 implanted in the sleeve support plate 7, and capable of moving up and down with a small stroke, and an inner peripheral surface of the die holder 11. And a mold body 13 fixed with bolts 12.

Reference numeral 14 denotes a fixed sleeve formed in a cylindrical shape with a step, which is inserted into a sleeve hole formed by three members 7, 11, and 13 of the lower mold 6, and has a sleeve support plate. The ring 15 is prevented from coming off from the sleeve hole by the screw 15. On the other hand, on the lower surface of the top plate 5, an upper mold substrate
The upper die is fitted in the base plate, a support plate 19 having a substantially octagonal shape in a plan view and integrally fixed to the base plate with a plurality of bolts 18, and a concave hole 19a of the support plate. It is formed of a mold holder 20 fixed and fixed, and a mold body 22 fitted in a concave hole of the mold holder and fixed with bolts 21.

[0008] At the lower end flange portion of the support plate 19 formed in a substantially octagonal shape, every other groove 19b is formed at the center of four sides, and the end face of each side provided with this groove 19b. , The cylinder support plate 23 is fixed with bolts by engaging the bulging portion with the concave structure. Numeral 25 denotes a core cylinder having a flange fixed to a bulging portion of each cylinder support plate and connected to a pressure oil source and provided with a limit switch for stroke control, and an action of a piston rod 26 of each core cylinder 25. A core 27 is fixed to the end. Although the movement of each core 27 is restricted by the core stopper ring 9 in the state shown in FIG. 1, when the lower surface of the core 27 rises above the upper surface of the upper die 16 and exceeds the upper surface of the core stopper ring 9, The piston rod 26 is configured to be opened in the radial direction at the same time by retreating. When the four cores 27 are closed as shown in FIG. 1, a perfect circle is formed by the four inner peripheral surfaces.
And, the upper and lower mold bodies 22, 13 that have been matched,
The four cores 27 closed form a cavity 28 composed of a disk portion 28a and a rim portion 28b.

A cylindrical injection sleeve 29 supported via a block on the upper end surface of an injection cylinder (not shown) is inserted into and removed from the inner hole of the fixed sleeve 14.
A plunger tip 30 as a head of the injection plunger 30 which moves forward and backward by the hydraulic pressure of the injection cylinder is provided in the inner hole.
a is fitted. Both sleeves 1 having the same diameter
Between the inner holes 14a and 29a of the holes 4 and 29 and the cavity 28, the plunger tip 30 is injected into the inner hole 14a.
A runner 31 is provided as a passage for the molten metal injected into the cavity 28 by the advance of a. This hot spring 31
Are inner holes 14a, 29 formed near the cavity 28.
a gate 31a as a cylindrical hole having a considerably smaller diameter than a,
The lower end surface of the disk portion 28a, which is formed by the tapered hole 31b formed near the inner hole 14a and follows the gate 31a, serves as a decorative surface of a product solidified in the cavity 28.

Outside the upper end of the annular rim portion 28b of the cavity 28, an annular runner 32 formed in an annular shape concentric with the rim portion 28b is provided on the lower end surface of the mold holder 20. The rim portion 28b is communicated with the rim portion 28b by a plurality of gates 33 formed in a radiation. Reference numeral 34 designates a degassing device for venting gas in the cavity 28 to the outside of the machine at the time of injection.
It is located between the upper mold 16 and the lower mold 6, and the gas venting device 34 is divided into a valve seat and a cylinder. The valve seat is divided into a front side and a paper back side in FIG. 1, and is formed so as to open integrally with each core 27 on both sides. The cylinder portion is supported by a piston rod 38 of a degassing cylinder 37 pivotally attached to the support plate 19 via links 39 and 40 so as to be movable in the axial direction.

The degassing device 34 is disclosed in, for example,
No. 9-309 and Japanese Patent Publication No. 61-41663.
And a valve for opening and closing the end valve seat portion thereof. During injection, the valve 34b is opened and gas is discharged by the pressure of the molten metal or the vacuuming device, and the inertia force or electric force of the molten metal The valve is closed by a signal or the like and the discharge of the molten metal to the outside of the valve seat is shut off. In addition, the cylinder portion 36 functions to ensure that the valve is opened and to hold the valve at each of the open and closed positions. When the upper mold 16 is opened and closed, the cylinder portion 36 retreats from the valve by the operation of the cylinder to permit the opening and closing thereof, , Together with the upper mold 16.

Next, mold clamping and mold opening will be described. The mold clamping is performed by lowering the top plate 5 against the hydraulic pressure of the mold opening / closing cylinder 3 by a mold clamping cylinder (not shown) from the mold matching state shown in FIG. 1, and the mold opening is performed after the mold clamping cylinder retreats. The operation is performed by advancing the piston rod 4 of the mold opening / closing cylinder 3 from the state shown in FIG.
Etc. rise together. Then, the product solidified by solidification in the cavity 28 reaches the upper mold 16 side by the mold opening and rises.

Next, the product and the annular runner 3 when the mold is opened.
A device for extruding the solidified material in 2 will be described. A pin extrusion cylinder 41 is fixed to the center of the top plate 5, and its piston rod 42 projects downward through a rod hole of the top plate 5. Reference numeral 43 denotes a round bar-shaped pin (pressing pin) having a screw hole screwed into a protruding screw portion of the piston rod 42 and extending downward. The diameter of the lower portion is slightly smaller than the diameter of the gate 31a. The pressing pin 43 is connected to the substrate 17.
Bearing 44, which is clamped and fixed between the support plate 19 and the support plate 19
9, a bearing 45 sandwiched and fixed between the support plate 19 and the mold body 22, and a cartridge 4 fixed to the mold body 22
6 are supported by shaft holes provided respectively in the vertical direction so as to be movable up and down. When the piston rod 42 advances and retreats by the hydraulic pressure of the extrusion cylinder 41 for the pressure pin, the pressure pin 43 moves to positions 1 and 3 described later. It is configured to move up and down between. In other words, the pressurizing pin is in a position when the molten metal is injected and filled (a state in which the pressurizing pin is retracted (the state in FIG. 1) / position 1) and a state in which the feeding operation is completed (in a state in which the pressurizing pin is advanced ( As shown in FIG. 2) / position 2) and as shown in FIG. 3, the biscuit is protruded (the pressure pin is most advanced / position 3). Melt 49 in cavity 28
When the pressing pin 43 advances to the position 2 before solidification, the pressing pin 43 removes the molten metal 49 and acts as a feeder, and a hole is penetrated through the gate 31a leaving a thin solidified molten metal. It is configured to: Then, as described later, when the pressing pin is advanced to the most advanced position of the position 3 before the mold and the biscuit are opened, the thin cylindrical solidified molten metal is cut and separated. The pressure pin 43 is provided with a cooling device having a hole for cooling water or the like, and is configured to cool the pin 43 heated by the molten metal.

The operation of the pressure casting apparatus (rotary type vertical injection apparatus) configured as described above will be described. The mold opening / closing unit 1 sprayed with the mold release agent at the upstream work station and matched to the mold is closed by the rotation of the rotary table, and then stops around the injection station, so that the top plate 5 is moved downward by the mold clamping cylinder. The mold is clamped by pressing. The injection sleeve 29 into which the molten metal 49 is injected at the same time as the mold clamping is fixed to the fixing sleeve 1.
When the injection plunger 30 is advanced by being inserted into the inner hole of No. 4 and joined, the molten metal 49 is injected into the cavity 28 and filled. Immediately before or immediately after the end of the injection, that is, before the molten metal 49 starts to solidify, the extrusion cylinder 4
When the first piston rod 42 is advanced by hydraulic pressure, the pressure pin 43 descends and protrudes from the cartridge 46, as shown by the chain line in FIG. 2, and is pushed into the molten metal 49 in the gate 31a. The molten metal 49 is removed by the pressure pin 43 and flows into the cavity 28, so that the molten metal 49 spreads to every corner of the cavity 28 by acting as a feeder. In this state, the molten metal starts to solidify, and after a predetermined time,
Solidification is completed to produce a product.

Then, the injection sleeve 29 and the plunger tip 30a are integrally retracted while maintaining the relative positional relationship. When the retreat of the injection unit is completed, the turntable rotates by 120 ° and the mold opening / closing unit 1 stops at the product removal station. In this case, as described above, since the pressure pin 43 is inserted into the gate 31a and the diameter difference from the gate 31a is small, a thin cylindrical solidified molten metal (biscuit) is formed around the pressure pin 43. Since the product 81 is formed, the product 80 in the cavity 28 is
There are six. Therefore, after the mold is stopped at the product removal position, the pressing pin 43 is further advanced to
By projecting 1, the biscuit 81 can be easily cut from the inside of the fixed sleeve 14 and the inside of the tapered hole 31b. Although the cut biscuit 81 falls downward, the biscuit processing can be automated by disposing a shooter or a conveyor at the drop position.

Next, the piston rod 4 moves forward by the hydraulic pressure of the mold opening / closing cylinder 3, and the top plate 5 rises.
The entire upper die 16 integral with this is raised and the mold is opened. After the mold is opened in this way, when the piston rod is retracted by the hydraulic pressure of the product extrusion cylinder, the extrusion plate starts to descend via the pin 55. As a result, first, an extrusion pin integrated with the extrusion plate is lowered, and a product whose tip abuts is extruded from the cavity 28.

As described above, according to the present invention, the operation of pressing the molten metal and the processing of the biscuit remaining in the gate portion can be processed by a simple apparatus and a simple method by increasing the stroke of the pressing pin. It was done. In order to operate long pressure pins smoothly under severe thermal conditions, design the pressure pins considering thermal expansion, select a spraying agent to prevent cooling and seizure, grasp the spray amount, It is also necessary to devise a cooling method from the inside of the pressure pin. For example, it is difficult to machine a long cooling hole having a small diameter like a pressure pin. For this, the pressure pin is divided into several parts (two to four divisions).
And facilitated drilling. The present invention has been accomplished by solving the above problems.

[0018]

According to the present method, since the biscuit is removed by the pressurizing plunger itself, a special drop-down device is not required, and the device can be made compact. Further, since the dropping operation is performed in the molding cycle, the molding cycle can be shortened.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a mold opening / closing unit used in the present invention.

FIG. 2 is an enlarged vertical sectional view of a main part of a mold opening / closing unit used in the present invention.

FIG. 3 is an explanatory view of a state where a biscuit is protruded by a pressing pin according to the present invention.

[Explanation of symbols]

 Reference Signs List 1 mold opening / closing unit 2 mounting plate 3 mold opening / closing cylinder 4 piston rod 5 top plate 6 lower mold 7 sleeve support plate 9 annular core stopper ring 10 guide pin 11 mold holder 13 mold body 14 fixing sleeve 16 upper mold Reference Signs List 20 mold holder 22 mold body 25 core cylinder 26 piston rod 27 core 28 cavity 28a disk part 28b rim part 29 injection sleeve 30 injection plunger 31 runner 31a gate 31b tapered hole 32 annular runner 33 gate (radial) 34 metal Mold degassing device 37 Degassing cylinder 41 Extrusion cylinder for pressure pin 43 Pin (pressure pin) 48 Molten solidified material 49 Molten metal 56 Extruded plate 63 Stopper 66 Extruded pin 80 Product 81 Molten solidified material (biscuit) 82 Inside annular liner Solidified

Claims (1)

[Claims] 1. A mold cavity is filled with molten metal by an injection device from a gate portion provided at a lower portion of a mold.
In a pressure casting method in which a pressure pin disposed at a position facing the gate portion is inserted into the molten metal to press the molten metal in the mold cavity, the molten metal solidifies and the plunger tip of the injection device is removed. A pressure casting method characterized by retreating and then advancing the pressure pin again to eject the solidified molten metal remaining in the gate portion.