JPH06143372A - Injecting device - Google Patents

Abstract

PURPOSE:To improve durability and control back pressure at measuring to a proper value. CONSTITUTION:A pressure plate 54 is arranged movably back and forth between a first plate 52 for fixing a heating cylinder 21 and a second plate 53, and the pressure plate 54 supports a screw rotatably. A motor is fixed to the second plate 53, a first clutch 62 is detachably arranged between the motor and a first drive shaft 73, the rotation of the motor is selectively transmitted to the screw, a second clutch 63 is detachably arranged between the motor and a second drive shaft 74, so that the rotation of the motor is selectively transmitted to the second drive shaft 74. A means for converting rotary motion into rectilinear motion is provided between the second drive shaft 74 and the pressure plate 54.

Description

Detailed Description of the Invention

[0001]

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

[0002]

2. Description of the Related Art Conventionally, a molding material which has been heated and melted in a heating cylinder, for example, a resin, is injected at high pressure, is filled in a cavity of a mold, and is cooled and solidified therein, and then the mold is molded. The injection molding machine, which is opened to take out the molded product, has the following structure.

That is, a mold clamping device and an injection device are installed on an injection molding machine frame. The mold clamping device includes a fixed platen and a movable platen, and a mold clamping cylinder reciprocates the movable platen. As a result, the fixed mold and the movable mold are brought into contact with and separated from each other. On the other hand, the injection device includes a heating cylinder that heats and melts the resin supplied from the hopper and an injection nozzle that injects the molten resin, and reciprocates to come in contact with and separate from the fixed mold.

FIG. 2 is a schematic view of an injection device in a conventional injection molding machine. In the figure, 2 is an injection device, 4 is an injection device frame, and a heating cylinder 21 having an injection nozzle 21a is fixed to the tip of the injection device frame 4. A hopper is provided in the heating cylinder 21, a screw (not shown) is rotatably disposed inside, and an end portion of the screw is rotatably supported by the support member 5.

A first servomotor 6 is attached to the support member 5, and the rotation of the first servomotor 6 is transmitted to the screw via a timing belt 7. Two screw shafts 8 are rotatably supported by the injection device frame 4 in parallel with the screw, and a rear end of the screw shaft 8 is attached to the injection device frame 4 by a second servomotor 9 mounted on the injection device frame 4. And the screw shaft 8 can be rotated by the second servomotor 9. The screw shaft 8 is screwed with the nut 5a fixed to the support member 5, and when the second servomotor 9 is driven, the screw shaft 8 rotates accordingly, and the nut 5a rotates. It is designed to move in the direction.

Next, the operation of the injection device having the above construction will be described. First, at the time of weighing, the first servomotor 6 is driven to rotate the screw via the timing belt 7 and retract the screw to a predetermined position. At this time, the resin charged from the hopper moves to the front of the screw in the heating cylinder 21 and is melted.

Next, at the time of injection, the heating cylinder 2
The injection nozzle 21a at the tip of No. 1 is pressed against a mold (not shown), the second servomotor 9 is driven, and the screw shaft 8 is rotated. At this time, the support member 5 advances as the screw shaft 8 rotates, and injects the resin accumulated in front of the screw from the injection nozzle 21a. However, in the injection device 2 having the above-mentioned configuration, the first servomotor 6 is required for rotating the screw at the time of weighing, and the second servomotor 9 is required for advancing the screw at the time of injection, resulting in high cost.

Therefore, there is provided an injection molding machine provided with only one servo motor for rotating the screw at the time of weighing and for advancing the screw at the time of injection. FIG. 3 is a schematic view of another injection device in a conventional injection molding machine. In the figure, 1 is a mold clamping device and 2 is an injection device. The mold clamping device 1 includes a tie bar 12 installed between a pair of fixed platens 10 and 11 on an injection molding machine frame 3.
And a movable platen 13 movably attached to the tie bar 12. A mold 14 is attached to each of the facing surfaces of the one fixed platen 11 and the movable platen 13, and a screw shaft 15 for converting a rotational force into a thrust is projected on the opposite surface of the movable platen 13. I am doing it. The screw shaft 15 is screwed into a turntable 16 which is rotatably attached to the other fixed platen 10. A gear 17 is attached to the rotary disc 16, and when the rotary disc 16 rotates together with the gear 17, the screw shaft 15 moves together with the movable platen 13 in accordance with the rotation.

On the other hand, the injection device 2 is provided with a heating cylinder 21 in which a screw 20 is arranged so as to be able to move forward and backward and rotatably, and to hold the heating cylinder 21 and to be movably supported on the injection molding machine frame 3. It has a housing 22. Inside the housing 22, the screw moving member 2
5 is mounted so as to be slidable in the front-rear direction, and a screw rotating gear 26 disposed at the rear end of the screw 20 is rotatably supported by the screw moving member 25.

A screw shaft 30 is screwed to the rear end of the screw moving member 25, is rotatably supported with respect to the housing 22, and is connected to a brake device 31 outside the housing 22. There is. The braking device 31 has a hysteresis brake inside.
Reference numeral 34 denotes a transmission shaft of the injection device 2, and a rear end of the transmission shaft 34 is connected to a servo motor 37 via a drive belt 38 outside the housing 22.
The transmission shaft 34 is rotated by 7. The transmission shaft 3
The front end of 4 is connected to the nozzle touch member 43 inside the housing 22. The nozzle touch member 43
Is rotatably supported by the housing 22,
The tip end has a screw shaft 43b that is screwed into the fixed platen 11.

An electromagnetic clutch mechanism 44 is provided between the nozzle touch member 43 and the transmission shaft 34.
Both are disengaged and selectively connected. Reference numeral 48 denotes a transmission gear attached to the transmission shaft 34 via an electromagnetic clutch mechanism 47, which meshes with the screw rotating gear 26. Next, the operation of the injection device having the above configuration will be described.

First, the servo motor 37 is rotated,
When the turntable 16 of the mold clamping device 1 is rotated, the screw shaft 1
5, the movable platen 13 moves, the mold is closed, and the mold is clamped. Then, when the mold clamping pressure reaches a predetermined pressure, in the injection device 2, the clutch mechanism 44 is engaged, and the transmission shaft 34 and the nozzle touch member 4 are engaged.
3 and are connected and rotate in the same direction.

The rotation of the nozzle touch member 43 causes the screw shaft 43b to enter the stationary platen 11 and draw the housing 22 toward the stationary platen 11. When the nozzle touch is confirmed, the nozzle touch member 43 is fixed to the housing 22 side by the electromagnetic brake 51, the clutch mechanism 44 is released, and the connection with the transmission shaft 34 is disconnected.

Next, when the electromagnetic clutch mechanism 46 is engaged, the rotation of the servo motor 37 is transmitted to the injection gear 29 via the transmission gear 36 and the like, and the screw shaft 30 is rotated. By the rotation of the screw shaft 30, the screw moving member 2
5 is advanced, and the screw 20 is advanced as the screw moving member 25 is advanced, and injection is performed. When the injection is completed, the servo motor 37 is stopped, and at the same time, the clutch mechanism 46 is released to stop the transmission of the rotation to the injection gear 29 and stop the screw moving member 25. In the transmission shaft 34, the clutch mechanism 47 is engaged to connect the transmission shaft 34 and the transmission gear 48.

In this way, when the servomotor 37 is driven, the transmission gear 48 rotates the rotation gear 26, and accordingly the screw 20 rotates to start weighing. At this time, the brake device 31 is activated to generate screw back pressure. The resin charged from the hopper is sent to the front of the screw 20 as the screw 20 rotates, and the screw 20 retreats together with the screw moving member 25 due to the pressure at that time.

When the measurement is completed, the servo motor 3
7 is stopped, the clutch mechanism 47 is released, and the connection with the transmission shaft 34 is disconnected.

[0017]

However, in the conventional injection device described above, the rotation of the screw at the time of weighing and the advancement of the screw at the time of injection can be performed by one servo motor 37, but the braking device 3 is used.
Since the back pressure at the time of measurement is generated by 1, it is difficult to control the back pressure to an appropriate value and durability is deteriorated.

According to the present invention, the problems of the conventional injection device can be solved, the screw can be rotated at the time of measurement and the screw can be advanced at the time of injection by one servo motor, and the cost can be reduced. An object of the present invention is to provide an injection device which can not only control the back pressure at the time of measurement to an appropriate value but also improve durability.

[0019]

Therefore, in the injection apparatus of the present invention, a screw is arranged in the heating cylinder so as to be movable forward and backward and rotatably. A pressure plate is movably arranged between a first plate that fixes the heating cylinder and a second plate that faces the first plate. The pressure plate rotatably rotates the screw. To support.

A motor is fixed to the second plate, and a first clutch is disengageably disposed between the motor and the first drive shaft to rotate the motor through the first drive shaft. And a second clutch is disengageably disposed between the motor and the second drive shaft to selectively transmit the rotation of the motor to the second drive shaft. A means for converting rotational movement into linear movement is provided between the second drive shaft and the pressure plate.

Further, a back pressure cylinder is fixed to the pressure plate, and the pressure plate is urged toward the first plate by fluid pressure to apply back pressure to the screw.

[0022]

According to the present invention, as described above, the screw is disposed in the heating cylinder so as to be movable forward and backward and rotatably.
A pressure plate is movably arranged between a first plate that fixes the heating cylinder and a second plate that faces the first plate. The pressure plate rotatably rotates the screw. To support.

A motor is fixed to the second plate, and a first clutch is disengageably disposed between the motor and the first drive shaft to rotate the motor through the first drive shaft. And a second clutch is disengageably disposed between the motor and the second drive shaft to selectively transmit the rotation of the motor to the second drive shaft. A means for converting rotational movement into linear movement is provided between the second drive shaft and the pressure plate.

Therefore, when the motor is rotated and the first clutch is engaged during metering, the rotation of the motor is transmitted to the screw via the first drive shaft, and the screw is retracted while rotating. Further, when the second clutch is engaged during injection, the rotation of the motor is transmitted to the second drive shaft, the rotational motion is converted into the linear motion, and the pressure plate is advanced to advance the screw.

Further, a back pressure cylinder is fixed to the pressure plate, and the pressure plate is urged toward the first plate side by fluid pressure to apply back pressure to the screw at the time of measurement. Therefore, not only the back pressure can be controlled to an appropriate value, but also the durability can be improved.

[0026]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 1 is a schematic view of an injection device showing an embodiment of the present invention. In the figure, 21 is a heating cylinder in which a screw (not shown) is arranged so as to be able to move forward and backward and rotatably, and 21 a is an injection nozzle arranged at the tip of the heating cylinder 21. The rear end of the heating cylinder 21 is fixed to the first plate 52, and the first plate 52 is fixed to the injection molding machine frame 3 (see FIG. 3). The injection molding machine frame 3 includes the first plate 5
The second plate 53 is fixed so as to face 2, and a support base 53a extending forward is formed above the second plate 53.

Reference numeral 61 denotes a servomotor which serves as a drive source for advancing the screw at the time of injection and rotating the screw at the time of measurement, and is fixed on the support base 53a. 6
Reference numerals 2 and 63 are first and second clutches for switching between the injection process and the measuring process. The first clutch 62 is engaged and the second clutch 63 is released during the measuring process, and the first clutch is released during the measuring process. The clutch 62 is released and the second clutch 63 is engaged.

Reference numeral 64 is a first belt pulley that transmits the rotation of the servo motor 61 during measurement, and 65 is a second belt pulley that transmits the rotation of the servo motor 61 during injection. Reference numeral 71 denotes a ball spline, which is rotatably arranged on the support base 53a to transmit the rotation to the first rotating shaft 72, and is also spline-fitted so that the first rotating shaft 72 is axially movable. Do it.

The first plate 52 and the second plate 53
A pressure plate 54 is movably disposed between the pressure plates 54, and the first rotary shaft 72 is rotatably supported by the bearings 55 on the pressure plate 54. The bearing 55 prevents relative movement in the axial direction between the first rotary shaft 72 and the pressure plate 54. A screw rotation shaft 56 is arranged at the rear end of the screw,
The rotation transmitted to the first drive shaft 73 is transmitted to the screw. The first drive shaft 73 is the pressure plate 5
It is rotatably attached to 4.

Therefore, when the second clutch 63 is released and the first clutch 62 is engaged at the time of measurement, the rotation of the servo motor 61 causes the ball spline 71, the first rotating shaft 72, the first belt pulley 64, and the first belt pulley 64 to rotate. It is transmitted to the screw via the drive shaft 73 and the screw rotating shaft 56, and is retracted while rotating the screw. Therefore, the resin fed from the hopper advances as the screw moves backward and is stored in front of the screw. At this time, the pressure plate 54 that rotatably supports the screw rotation shaft 56 and the first drive shaft 73 also retracts as the screw retracts.

On the other hand, 75 is a second rotary shaft rotatably supported by the second plate 53, and 74 is a second rotary shaft 75.
And a second drive shaft rotatably supported by the second plate 53, 57 is a ball screw formed on the second drive shaft 74, and 58 is a ball screw 57. A ball nut that is screwed onto the pressure plate 54 and is fixed to the pressure plate 54.

Therefore, when the first clutch 62 is released and the second clutch 63 is engaged during injection, the rotation of the servo motor 61 is transmitted to the ball screw 57 via the second belt pulley 65. Then, when the ball screw 57 rotates, the ball nut 58 is linearly moved along with the rotation, and this linear movement is performed by the pressure plate 5.
4, transmitted to the screw via the first drive shaft 73 and the screw rotation shaft 56, and advances the screw. As the screw advances, the resin accumulated in front of the screw at the time of measurement is injected from the injection nozzle 21a and is filled in the cavity of the mold (not shown).

The ball screw 57 naturally rotates relative to the ball nut 58 as the pressure plate 54 retracts during measurement, and does not become a resistance. As described above, by using one servo motor 61 and selectively engaging and disengaging the first and second clutches 62 and 63, the screw can be advanced during injection, and the screw can be rotated and retracted during measurement. it can.

A back pressure cylinder 67 is provided to apply a back pressure to the screw that retreats during measurement.
In the present embodiment, the back pressure cylinder 67 is described as a hydraulic cylinder, but a pneumatic cylinder can also be used. The back pressure cylinder 67 has a front end fixed to the pressure plate 54 and a rear end extending toward the second plate 53. The piston 6 is placed inside the back pressure cylinder 67.
7a is slidably arranged, and the pressure plate 5
An oil chamber 67b is formed on the fourth side. Guide bars 77 are fixed to both sides of the piston 67a, and a front end of the guide bar 77 is fixed to the first plate 52 and a rear end of the guide bar 77 is fixed to the second plate 53.

Reference numeral 78 is a hydraulic pressure source for exerting pressure on the back pressure cylinder 67, 79 is a filter, 80 is a pressure reducing valve for supplying oil of a constant pressure to the oil chamber 67b of the back pressure cylinder 67, 81 Is a switching valve that takes A position and B position, 8
A silencer 2 is connected to a chamber on the back side of the piston 67a of the back pressure cylinder 67. Therefore, when the switching valve 81 is placed in the A position, the oil in the oil chamber 67b is drained and the back pressure is not applied. Further, when the switching valve 81 is placed at the position B, the oil whose pressure has been reduced by the pressure reducing valve 80 is supplied into the oil chamber 67b, presses the pressure plate 54 toward the first plate 52 side, and applies back pressure to the screw.

The present invention is not limited to the above-mentioned embodiments, but can be variously modified within the scope of the present invention, and they are not excluded from the scope of the present invention.

[0037]

As described in detail above, according to the present invention, the screw is arranged in the heating cylinder so as to be movable forward and backward and rotatably. A pressure plate is movably arranged between a first plate that fixes the heating cylinder and a second plate that faces the first plate. The pressure plate rotatably rotates the screw. To support.

A motor is fixed to the second plate, and a first clutch is disengageably disposed between the motor and the first drive shaft to rotate the motor through the first drive shaft. And a second clutch is disengageably disposed between the motor and the second drive shaft to selectively transmit the rotation of the motor to the second drive shaft. A means for converting rotational movement into linear movement is provided between the second drive shaft and the pressure plate.

Therefore, by disposing one motor, it is possible to retract the screw while rotating it by engaging the first clutch during metering, and by engaging the second clutch during injection, the screw can be retracted. It can be advanced and the cost can be reduced. Furthermore, a back pressure cylinder is fixed to the pressure plate, and the fluid pressure urges the pressure plate toward the first plate to apply back pressure to the screw. Therefore, not only the back pressure at the time of measurement can be controlled to an appropriate value, but also the durability can be improved.

[Brief description of drawings]

FIG. 1 is a schematic view of an injection device showing an embodiment of the present invention.

FIG. 2 is a schematic view of an injection device in a conventional injection molding machine.

FIG. 3 is a schematic view of another injection device in the conventional injection molding machine.

[Explanation of symbols]

 20 screw 21 heating cylinder 21a injection nozzle 52 first plate 53 second plate 54 pressure plate 61 servo motor 62 first clutch 63 second clutch 67 back pressure cylinder 73 first drive shaft 74 second drive shaft

Claims (1)

[Claims] 1. A heating cylinder; (b) a screw disposed in the heating cylinder so as to be movable back and forth and rotatably; (c) a first plate for fixing the heating cylinder; ) A second plate arranged to face the first plate, and (e) a pressure plate which is arranged between the first plate and the second plate so as to be movable forward and backward and rotatably supports the screw. (F) a motor fixed to the second plate, and (g) a first clutch that is disengageably disposed and that selectively transmits the rotation of the motor to a screw via a first drive shaft, (H) It is arranged to be detachable,
A second for selectively transmitting the rotation of the motor to a second drive shaft
A clutch, (i) means for converting a rotational motion into a linear motion between the second drive shaft and the pressure plate, and (j) fixed to the pressure plate so that the pressure plate moves to the first plate side by fluid pressure. An injection device comprising a back pressure cylinder for energizing and applying a back pressure to the screw.