JP3301742B2 - Injection equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an injection device.

[0002]

2. Description of the Related Art Conventionally, an injection molding machine is provided with an injection device, and a screw is rotatably and advancing and retracting in a heating cylinder of the injection device. It can be rotated and moved forward and backward by an injection motor. A spiral flight is formed on the body of the screw, that is, the outer peripheral surface of the screw body, and a groove is formed by the flight. Then, when the screw is rotated in the forward direction during the measuring step, the resin dropped from the hopper attached to the upper portion of the heating cylinder is advanced along the groove while being melted, and is stored in front of the screw head. The screw is then retracted accordingly. Further, when the screw is advanced during the injection step, the resin stored in front of the screw head is injected from the injection nozzle, and is filled in the cavity space of the mold apparatus.

For this purpose, a resin supply port is formed at a predetermined position of the heating cylinder, and the resin dropped from the hopper is supplied into the heating cylinder via the resin supply port. In the flight section where the flight is formed, a resin supply section to which the resin is supplied, a compression section to melt the supplied resin while compressing the supplied resin, and a fixed amount of the melted resin from the rear to the front. A weighing unit for weighing each is formed. The resin in the groove has a pellet-like shape in the resin supply section, becomes a semi-molten state in the compression section, and becomes completely liquid in the measuring section.

By the way, if the outer peripheral surface of the screw and the inner peripheral surface of the heating cylinder have the same roughness, even if the screw is rotated during the measuring step, the resin in the groove is rotated integrally with the screw. Do not move forward. Therefore, usually, the inner peripheral surface of the heating cylinder is made rougher than the outer peripheral surface of the screw.

[0005]

However, in the above-mentioned conventional injection device, the resin supplied into the heating cylinder is pressed by the load of the resin from the hopper side, and the flight and the heating cylinder are pressed in the pressed state. When the screw is advanced in the injection step, a large frictional resistance is applied to the resin near the inner peripheral surface of the heating cylinder.

Therefore, the injection power applied to the screw from the rear does not correspond to the injection pressure applied to the front end of the screw head, and the resin cannot be injected with a sufficient injection pressure. As a result, the resin pressure in the cavity space, that is, the pressure inside the mold varies, and the quality of the molded product is deteriorated.

The present invention solves the above-mentioned problems of the conventional injection device, can reduce the frictional resistance applied to the resin in the injection step, can improve the quality of the molded product, and can improve the quality of the molded product. An object of the present invention is to provide an injection device capable of stabilizing the quality of a product.

[0008]

For this purpose, in the injection apparatus of the present invention, a heating cylinder having a resin supply port formed at a predetermined position and a flight section having a flight and a groove formed on an outer peripheral surface of a screw body. And a screw head disposed at the front end of the flight section, and a screw disposed rotatably in the heating cylinder and movable back and forth, and heated via the resin supply port during the measuring step. A resin supply device for supplying the resin into the cylinder.

The resin supply port is formed at a position just below the heating cylinder.

In another injection device of the present invention, the resin supply port is formed at the lowermost portion of the heating cylinder. The resin supply device supplies the resin from below the heating cylinder.

[0011]

[0012]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is an enlarged view of a main part of an injection device according to an embodiment of the present invention, FIG. 2 is a view showing an arrangement of a resin supply device according to the embodiment of the present invention, and FIG. It is a conceptual diagram of an injection device.

In FIG. 1, reference numeral 11 denotes a heating cylinder as a cylinder member; 12, a screw as an injection member disposed rotatably and advancing and retracting in the heating cylinder 11; 13, a front end of the heating cylinder 11; An injection nozzle formed at the left end in FIG. 2, a nozzle opening 14 formed at the injection nozzle 13, and a nozzle 15 formed at a predetermined position near the rear end (the right end in FIG. 2) of the heating cylinder 11. The resin supply port 16 is
And a resin supply device that supplies the resin into the heating cylinder 11 through the resin supply port 15.

The screw 12 has a flight section 21,
And a screw head 27 disposed at the front end of the flight section 21. The flight part 21 is a flight 2 formed in a spiral shape on the outer peripheral surface of the screw body.
The flight 23 forms a spiral groove 24. In the flight section 21, the resin supply section P <b> 1 to which the resin is supplied by the resin supply apparatus 16 in order from the rear (the right in FIG. 2) to the front (the left in FIG. 2) compresses the supplied resin. A compression section P2 for melting while melting and a measuring section P3 for measuring a fixed amount of the melted resin are formed. The bottom of the groove 24, that is, the outer diameter of the groove bottom is made relatively small in the resin supply part P1, gradually increased from the rear to the front in the compression part P2, and made relatively large in the measurement part P3. Therefore, a gap (gap) between the inner peripheral surface of the heating cylinder 11 and the outer peripheral surface of the shaft of the screw 12 is relatively large in the resin supply part P1, and gradually decreases from the rear to the front in the compression part P2. Then, it is made relatively small in the measuring section P3.

When the screw 12 is rotated in the forward direction during the measuring process, the resin supplied into the heating cylinder 11 through the resin supply port 15 by the resin supply device 16 is melted along the groove 24 while being melted. The screw 12 is moved forward (moves to the left in FIG. 2) and stored in front of the screw head 27, and accordingly, the screw 12 is moved backward (moves to the right in FIG. 2). The groove 24
The resin inside has a pellet-like shape in the resin supply section P1 as shown in FIG. 2, is in a semi-molten state in the compression section P2, is completely melted in the measurement section P3 and is in a liquid state.

In the injection step, the screw 12
Is advanced, the resin stored in front of the screw head 27 is injected from the injection nozzle 13 and filled in a cavity space of a mold device (not shown). At this time,
A backflow prevention device is provided around the screw head 27 so that the resin stored in front of the screw head 27 does not flow backward.

For this purpose, the screw head 27
Has a conical (conical) head body 25 in the front half (the left half in FIG. 2) and a column 26 in the rear half (the right half in FIG. 2). An annular check ring 28 is rotatably disposed on the outer periphery of the cylindrical portion 26, and a presser 29 is fixed to the front end of the flight portion 21.

In the check ring 28, holes 28a extending in the axial direction are formed at a plurality of positions in the circumferential direction, and cutouts 28b are formed in the front end at predetermined angles. Then, a locking projection 25a is formed on the head body 25, and the locking projection 25a is placed in the notch 28b. In this case, the check ring 28 is
With the rotation of the screw head 27, the screw head 27 is rotated by a predetermined angle θ, and further rotation is restricted.

On the other hand, holes 29a extending in the axial direction corresponding to the holes 28a are formed at a plurality of positions in the circumferential direction of the presser 29, and the check ring 28 is rotated with respect to the screw head 27. As a result, the holes 28a and 29a are selectively communicated with each other. Accordingly, the check ring 28 has a communication position for communicating the front of the screw head 27 with the flight portion 21 and a blocking position for blocking the front of the screw head 27 and the flight portion 21. The backflow prevention device includes a check ring 28 and a presser 29.

The rear end (right end in FIG. 3) of the heating cylinder 11 is attached to a front injection support 31, and a rear injection support 32 is disposed at a predetermined distance from the front injection support 31. A guide bar 33 is provided between the front injection support 31 and the rear injection support 32, and a pressure plate 34 is disposed along the guide bar 33 so as to be able to advance and retreat. The front injection support 31 and the rear injection support 32 are
It is fixed to a slide base (not shown) by bolts (not shown).

A drive shaft 35 is connected to the rear end of the screw 12, and the drive shaft 35
Is rotatably supported on the pressure plate 34 by bearings 36 and 37. An electric measuring motor 41 is provided as a first driving means, and a first rotation transmission means including pulleys 42 and 43 and a timing belt 44 is provided between the measuring motor 41 and the drive shaft 35. The metering motor 41
, The screw 12 can be rotated in the forward or reverse direction. In this embodiment, the electric weighing motor 41 is used as the first driving means.
Alternatively, a hydraulic motor can be used.

A ball screw 47 composed of a ball screw shaft 45 and a ball nut 46 screwed to each other is provided behind the pressure plate 34 (to the right in FIG. 3). Motion direction conversion means for converting the motion into a linear motion is configured. The ball screw shaft 45 is rotatably supported by the rear injection support 32 by a bearing 48, and the ball nut 46 is formed by a plate 51 and a load cell 52.
And is fixed to the pressure plate 34 via.

Further, an injection motor 53 as a second driving means is provided, and a second rotation unit comprising pulleys 54 and 55 and a timing belt 56 is provided between the injection motor 53 and the ball screw shaft 45. Since the transmission means is arranged,
By driving the injection motor 53 and rotating the ball screw shaft 45, the ball nut 46 is moved to move the screw 12 forward (moving leftward in FIG. 3) or retreating (moving rightward in FIG. 3). be able to. In this embodiment, the injection motor 53 is used as a means for moving the pressure plate 34, but an injection cylinder may be used instead of the injection motor 53.

When the resin supplied into the heating cylinder 11 through the resin supply port 15 is caught between the flight 23 and the heating cylinder 11, when the screw 12 is advanced in the injection process, In addition, a large frictional resistance is applied to the resin near the inner peripheral surface of the heating cylinder 12.

In this case, the injection power applied to the screw 12 from the rear does not correspond to the injection pressure applied to the front end of the screw head 27, and the resin cannot be injected with a sufficient injection pressure. As a result, the pressure in the mold is varied, and the quality of the molded product is reduced.

Therefore, the resin supply device 16 is heated so that a load is not applied from the resin supply port 15 side to the heating cylinder 11 side to the resin supplied into the heating cylinder 11 through the resin supply port 15. The resin supply device 16 is formed at the lowermost part of the cylinder 11 and supplies the resin from below the heating cylinder 11.

For this purpose, the resin supply device 16 is provided with a cylindrical first resin guide portion 61 which is communicated with the resin supply port 15 and extends vertically, and a lower end of the first resin guide portion 61. A resin push-up device 63 that pushes up the resin toward the resin supply port 15 and extends horizontally in communication with the first resin guide portion 61 and is connected to a resin supply source (not shown). And a feed screw 68 rotatably disposed in the second resin guide 67. The resin lifting machine 63 includes a cylinder 64 as first resin supply driving means, and a pusher 65 which is moved forward and backward by driving the cylinder 64. The cylinder 64 is driven by a control device (not shown). The feed screw 68 is connected to a resin supply motor (not shown) serving as a second resin supply drive unit, and the resin supply motor is driven by the control device.

During the measuring step, the control device
By driving the resin supply motor, the feed screw 68
Is rotated, and the resin is conveyed from the resin supply source and supplied into the first resin guide portion 61. Subsequently, the control device drives the cylinder 64 to move the pusher 65 forward (FIG. 1).
), And pushes up the resin supplied into the first resin guide portion 61 to thereby lower the heating cylinder 11 from below.
Supply within. Note that the resin supply motor and the cylinder 64 are not driven during the injection step.

In this case, no load is applied to the resin supplied into the heating cylinder 11 from the resin supply port 15 side toward the heating cylinder 11 side.
And the heating cylinder 11 can be prevented from being caught. Therefore, in the injection step, when the screw 12 is advanced, the frictional resistance applied to the resin near the inner peripheral surface of the heating cylinder 12 can be reduced.
As a result, the injection power corresponds to the injection pressure, so that the resin can be injected with a sufficient injection pressure. And, since it is possible to prevent the variation in the mold inner pressure,
The quality of the molded article can be improved.

In the present embodiment, after the resin is conveyed by the feed screw 68, the resin is supplied from below the heating cylinder 11 by advancing the pusher 65. And the resin can be supplied directly from below the heating cylinder 11 by a feed screw. In that case, the feed screw 68 becomes unnecessary.

In the above-described embodiment, the resin supply port 15 is formed at the lowermost portion of the heating cylinder 11, but the resin supply port may be formed at a position immediately below the heating cylinder 11. In addition, a check ring that moves in the axial direction can be used for the backflow prevention device.

The present invention is not limited to the above embodiment, but can be variously modified based on the gist of the present invention, and they are not excluded from the scope of the present invention.

[0034]

As described above in detail, according to the present invention, in the injection apparatus, a heating cylinder having a resin supply port formed at a predetermined position and a flight and a groove formed on the outer peripheral surface of the screw body. A flight unit, and a screw head disposed at the front end of the flight unit, a screw rotatably disposed within the heating cylinder, and disposed to be able to advance and retreat, and the resin supply port during a measuring step. And a resin supply device for supplying the resin into the heating cylinder via the heating device.

The resin supply port is formed at a position just below the heating cylinder.

In this case, no load is applied to the resin supplied into the heating cylinder from the side of the resin supply device in the measuring step, so that the resin is prevented from being caught between the flight and the heating cylinder. it can. Therefore, in the injection step, when the screw is advanced, the frictional resistance applied to the resin near the inner peripheral surface of the heating cylinder can be reduced. As a result, the injection power corresponds to the injection pressure, so that the resin can be injected with a sufficient injection pressure. Further, since it is possible to prevent the variation in the mold inner pressure, it is possible to improve the quality of the molded product.

[Brief description of the drawings]

FIG. 1 is an enlarged view of a main part of an injection device according to an embodiment of the present invention.

FIG. 2 is a view showing an arrangement of a resin supply device according to the embodiment of the present invention.

FIG. 3 is a conceptual diagram of an injection device according to an embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Heating cylinder 12 Screw 15 Resin supply port 16 Resin supply device 21 Flight part 23 Flight 24 Groove 27 Screw head

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) B29C 45/18-45/62

Claims (2)

(57) [Claims] 1. A (a) a heating cylinder a resin supply port is formed at a predetermined position, the flight portion formed flight and grooves on the outer peripheral surface of the (b) a screw body, and distribution to the front end of the flight portion A screw provided rotatably and advancing and retracting in the heating cylinder, provided with a screw head provided, and (c) supplying the resin into the heating cylinder via the resin supply port during the measuring step. (D) the resin supply port is formed at a position directly below a heating cylinder. 2. The injection device according to claim 1, wherein (a) the resin supply port is formed at a lowermost portion of a heating cylinder, and (b) the resin supply device supplies the resin from below the heating cylinder.