JPH07112468A - Local pressure type injection molding machine - Google Patents

Abstract

PURPOSE:To enhance the accuracy of the speed or position of a pressure pin and to miniaturize and simplify a structure. CONSTITUTION:A fixed mold 12, a movable mold 14, the pressure pin 35 piercing the movable mold 14 to extend and allowed to face to a cavity 21 at the leading end thereof and the drive means allowing the pressure pin 35 to advance are provided. The drive means is equipped with a motor, a linear motion generator 64 converting the rotary motion generated by the motor to linear motion and a setting device 82 setting the operation pattern of the motor. By controlling the motor by detecting the speed or position of the pressure pin, the accuracy of the speed or position of the pressure pin 35 can be enhanced. Since it is unnecessary to arrange a return spring, a stopper and a position detector, a structure can be miniaturized and simplified.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a local pressure type injection molding machine.

[0002]

2. Description of the Related Art Conventionally, in a local pressure type injection molding machine, a tip of an ejector pin is made to face a cavity, a tip of the pressure pin is made to face a processing part of the article, and the ejector pin is advanced to make Then, the molded product can be processed by pushing down and pushing the pressure pin forward.

FIG. 2 is a sectional view of a conventional local pressure injection molding machine. In the figure, 11 is a fixed side attachment plate, and the fixed mold 12 is attached to a fixed platen (not shown) via the fixed side attachment plate 11. Then, the injection nozzle of the injection device (not shown) advances in the plasticizing movement process, and the tip of the injection nozzle has the sprue bush 13 of the fixed mold 12.
Be contacted with.

On the other hand, a movable platen (not shown) is moved forward and backward (moved in the left-right direction in the figure) by a mold clamping device (not shown) to bring the movable mold 14 into and out of contact with the fixed mold 12. Therefore, the movable mold 14 is attached to the movable platen via the movable side mounting plate 15 and a spacer block (not shown). Then, the resin injected from the injection nozzle passes through the sprue 18 and the runner 19, and is filled (sufficiently) into the cavity 21 formed between the fixed mold 12 and the movable mold 14 via the gate 20.

When the injection process is completed, a pressure-holding process is subsequently performed, the resin pressure in the cavity 21 is maintained, and the resin starts to be cooled. After a certain period of time, a molded product (not shown) is left on the movable mold 14 side. In this state, the two molds 12 and 14 are opened, and the molded product is pushed down by the ejector device. Therefore, the sprue lock pin 25 and the ejector pin 26 are provided. The sprue lock pin 25 is disposed so as to face the sprue 18, and holds a molded product when the mold is opened and leaves it on the movable mold 14 side. The ejector pin 26 is disposed with its tip facing the cavity 21, the runner 19, etc., and the molded product is moved to the movable mold 1 after the mold is opened.
Separate from 4 and push down.

The sprue lock pin 25 and the ejector pin 26 penetrate the movable mold 14 and extend rearward (to the left in the figure), and the head portion formed at the rear end is held by ejector plates 51 and 52. Fixed. Then, the rod 23 can be brought into contact with the ejector plate 51, and the sprue lock pin 25 and the ejector pin 26 are advanced as the rod 23 moves forward.

By the way, a pressure pin 35 is provided to process the molded product during the pressure-holding step.
The pressurizing pins 35 are arranged in a required number such that the tips thereof face predetermined positions such as the cavity 21 and the gate 20, and extend through the movable mold 14 and the ejector plates 51 and 52 to the rear side. The head portion formed at the end is clamped and fixed by the pressure plates 36 and 37.

The pressure plates 36 and 37 are disposed so as to be able to come into contact with and separate from the movable side mounting plate 15, and are moved forward and backward by two pressure cylinders 41. That is, the piston rod 42 of the pressurizing cylinder 41 is replaced by the cross rod 53.
The pressure rod 54 is fixed to the cross rod 53. The pressure rod 54 is attached to the movable side mounting plate 1
The pressure pin 35 can be pushed out by penetrating the pressure plate 35 and coming into contact with the pressure plate 36.

The hydraulic pressure supplied to the pressurizing cylinder 41 is controlled by a proportional pressure reducing valve or a servo valve (not shown). By electrically controlling the proportional pressure reducing valve or the servo valve, the pressurizing pin 35 is gradually advanced while vibrating to apply a pulse-like pressure force to the resin of the processed portion of the molded product to excite (displace). Then, the molded product can be subjected to predetermined processing.

Even if the pressurizing pin 35 is moved forward by using the proportional pressure reducing valve or the servo valve, the resin cannot be excited. Further, a reaction force is required to excite the resin by the applied pressure, and the pressure pin 35 must be forcibly retracted from the processing portion. Therefore, a highly responsive return spring 40 that surrounds the four return pins 38 is provided between the pressure plate 37 and the movable mold 14. The pressure pin 35 and the return pin 38 both have a head portion formed at their rear ends.
The head portion is sandwiched and fixed by the pressure plates 36 and 37. In this case, four return springs 40
By uniformly arranging the pressure plates 36, 3
7 can be moved in parallel without tilting, and a smooth operation can be obtained.

[0011]

However, in the conventional local pressurization type injection molding machine, the pressurizing cylinder 4 is used.
Since the pressurizing pin 35 is advanced and retracted by controlling the hydraulic pressure supplied to 1 by a proportional pressure reducing valve or a servo valve, the accuracy of the speed and position of the pressurizing pin 35 cannot be improved.

Further, not only is it necessary to dispose a highly responsive return spring 40 between the pressure plate 37 and the movable mold 14 in order to vibrate the pressure pin 35,
In order to limit the stroke of the pressure pin 35, it is necessary to dispose a mechanical stopper (not shown), a position detector or the like, which makes the structure large and complicated. The present invention solves the problems of the local pressure injection molding machine, improves the accuracy of the speed and position of the pressure pin, and can reduce the size and simplify the structure. An object is to provide a molding machine.

[0013]

Therefore, in the local pressure type injection molding machine of the present invention, a fixed mold and a movable mold which is disposed so as to come in contact with and separate from the fixed mold and forms a cavity therebetween. The mold includes a mold, a pressure pin extending through the movable mold and having a tip facing the cavity, and a driving unit for moving the pressure pin forward.

The driving means comprises a motor, a linear motion generating device for converting the rotational motion generated by the motor into a linear motion, and a setting device for setting an operation pattern of the motor.

[0015]

According to the present invention, as described above, the local pressure type injection molding machine includes a fixed mold and a movable mold which is disposed so as to come in contact with and separate from the fixed mold and forms a cavity therebetween. , A pressing pin extending through the movable mold and having a tip facing the cavity, and a driving means for moving the pressing pin forward.

The driving means comprises a motor, a linear motion generating device for converting the rotational motion generated by the motor into a linear motion, and a setting device for setting an operation pattern of the motor. Therefore, the motor is driven, and the rotary motion generated by the motor is converted into the linear motion by the linear motion generator and transmitted to the pressing pin. Then, the pressure pin can be gradually advanced while vibrating to apply a pulsed pressure to the resin in the processed portion of the molded product to excite it, and the predetermined processing can be performed on the molded product.

[0017]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 1 is a schematic view of a local pressure type injection molding machine showing an embodiment of the present invention. In the figure, 11
Is a fixed side attachment plate, and the fixed mold 12 is attached to a fixed platen (not shown) via the fixed side attachment plate 11. Then, the injection nozzle of the injection device (not shown) advances in the plasticizing movement step, and the tip of the injection nozzle is brought into contact with the sprue bush 13 of the fixed mold 12.

On the other hand, the movable platen (not shown) is moved back and forth (moved in the left-right direction in the figure) by a mold clamping device (not shown) to bring the movable mold 14 into and out of contact with the fixed mold 12. Therefore, the movable mold 14 is attached to the movable platen via the movable side mounting plate 15 and a spacer block (not shown). Then, the resin injected from the injection nozzle passes through the sprue 18, the runner 19, and the gate 20 to fill the cavity 21 formed between the fixed mold 12 and the movable mold 14.

When the injection step is completed, a pressure holding step is subsequently carried out, the resin pressure in the cavity 21 is maintained, and the resin starts to be cooled, and after a certain period of time, a molded product (not shown) is left on the movable mold 14 side. In this state, the two molds 12 and 14 are opened, and the molded product is pushed down by the ejector device. Therefore, the sprue lock pin 25 and the ejector pin 26 are provided. The sprue lock pin 25 is disposed so as to face the sprue 18, and holds a molded product when the mold is opened and leaves it on the movable mold 14 side. The ejector pin 26 is disposed with its tip facing the cavity 21, the runner 19, etc., and the molded product is moved to the movable mold 1 after the mold is opened.
Separate from 4 and push down.

The sprue lock pin 25 and the ejector pin 26 penetrate the movable mold 14 and extend rearward (to the left in the drawing), and the head portion formed at the rear end is held by ejector plates 51 and 52. Fixed. Then, the rod 23 can be brought into contact with the ejector plate 51, and the sprue lock pin 25 and the ejector pin 26 are advanced as the rod 23 moves forward.

By the way, a pressure pin 35 is provided for processing the molded product during the pressure-holding step.
The pressurizing pins 35 are arranged in a required number such that the tips thereof face predetermined portions such as the cavity 21 and the gate 20, and extend through the movable mold 14 and the ejector plates 51 and 52 to the rear and It is moved back and forth by a driving device 61 as driving means arranged in the. Then, the driving device 61 gradually moves forward while vibrating the pressure pin 35 to apply a pulse-like pressure force to the resin in the processed portion of the molded product to excite (displace) it to a predetermined position with respect to the molded product. It can be processed.

The driving device 61 includes a servo motor 63, a linear motion generating device 64 for converting the rotary motion generated by the servo motor 63 into a linear motion, and an arrangement between the servo motor 63 and the linear motion generating device 64. Was set up,
It consists of a transmission device 65 for transmitting a rotary movement. A stepping motor may be used instead of the servo motor 63.

In the present embodiment, the linear motion generating device 64 includes a ball nut 67 arranged at the rear end of the pressure pin 35 and a spline portion 69 formed at the rear end of the pressure pin 35. Consists of. Then, the spline section 6
Reference numeral 9 is spline-connected to the case 68 of the local pressure injection molding machine to prevent the pressure pin 35 from rotating. A key may be used instead of the spline portion 69.

The transmission device 65 includes a pulley 71 fixed to the rotary shaft of the servo motor 63, a pulley 72 fixed to the outer periphery of the ball nut 67, and a tension between the pulley 72 and the pulley 71. The belt 73 is provided. A rack and pinion can be used as the linear motion generating device 64, and the transmission device 6 can be used.
It is also possible to use a chain as 5.

The rotation generated by the servo motor 63 is transmitted to the ball nut 67 via the pulley 71, the belt 73 and the pulley 72, and the ball nut 6
The rotary motion is converted into a linear motion by 7. A ball screw (not shown) that is screwed into the ball nut 67 is formed at the rear end of the pressure pin 35.

An axial load detector 78 is built in the pressurizing pin 35, and the pressure signal detected by the axial load detector 78 is sent to the comparator 81. The comparator 81 compares the pressure signal with the pressure set value set by the setter 82, and outputs a deviation signal to the servo amplifier 84.
The operation pattern of the pressure pin 35 is set in the setter 82 according to the axial load, speed, position, etc. of the pressure pin 35. Then, the servo amplifier 84 generates a pressure command signal based on the deviation signal and outputs the pressure command signal to the servo motor 63. In this way, the pressure control of the servo motor 63 can be performed.

Further, an encoder 91 is arranged in the servo motor 63, and the speed or position of the pressure pin 35 can be detected by the encoder 91. Then, the speed signal or the position signal detected by the encoder 91 is sent to the comparator 92. The comparator 92 compares the speed signal or position signal with the speed setting value or position setting value set by the setter 82, and outputs a deviation signal to the servo amplifier 84. Then, the servo amplifier 84 generates a speed command signal or a position command signal based on the deviation signal, and outputs the speed command signal or the position command signal to the servo motor 63. In this way, the servo motor 63
The speed control or the position control can be performed, and the controllability can be improved.

The present invention is not limited to the above-mentioned embodiments, but various modifications can be made based on the spirit of the present invention, and these are not excluded from the scope of the present invention.

[0029]

As described above in detail, according to the present invention, the local pressurizing type injection molding machine is provided with a fixed mold and a fixed mold so that the cavity can be formed between the fixed mold and the fixed mold. A movable die, a pressure pin that extends through the movable die and has a tip facing the cavity, and a drive unit that advances the pressure pin.

The driving means comprises a motor, a linear motion generating device for converting the rotational motion generated by the motor into a linear motion, and a setting device for setting an operation pattern of the motor. Therefore, by detecting the speed and position of the pressure pin and controlling the motor, the accuracy of the speed and position of the pressure pin can be improved.

Further, it is not necessary to dispose a highly responsive return spring for vibrating the pressure pin, and mechanical stoppers, position detectors, etc. are disposed to limit the stroke of the pressure pin. Since it is not necessary, the structure can be downsized and simplified.

[Brief description of drawings]

FIG. 1 is a schematic view of a local pressure type injection molding machine showing an embodiment of the present invention.

FIG. 2 is a sectional view of a conventional local pressure injection molding machine.

[Explanation of symbols]

 12 Fixed mold 14 Movable mold 21 Cavity 35 Pressure pin 61 Drive device 63 Servo motor 64 Linear motion generator 82 Setting device

Claims (1)

[Claims] 1. (a) a fixed mold, (b) a movable mold which is disposed so as to come into contact with and separate from the fixed mold and forms a cavity between the two, and (c) penetrates the movable mold. And a drive means for advancing the pressure pin, and (e) the drive means is generated by the motor. A local pressurizing injection molding machine comprising: a linear motion generating device that converts a rotary motion into a linear motion; and a setting device that sets an operation pattern of the motor.