JP2849292B2 - 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 for an injection molding machine.

[0002]

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

That is, a mold clamping device and an injection device are provided 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. Thus, the fixed mold and the movable mold come and go. On the other hand, the injection device comprises a heating cylinder for heating and melting the resin supplied from the hopper, and an injection nozzle for injecting the molten resin, and reciprocates so as to approach 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, reference numeral 2 denotes an injection device, 4 denotes an injection device frame, and a heating cylinder 21 having an injection nozzle 21a disposed at the tip of the injection device frame 4 is fixed. A hopper is provided in the heating cylinder 21, and a screw (not shown) is rotatably disposed inside the heating cylinder 21, and an end of the screw is rotatably supported by the support member 5.

[0005] 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. Further, two screw shafts 8 are rotatably supported on the injection device frame 4 in parallel with the screw, and a rear end of the screw shaft 8 is connected to a second servo motor 9 attached to the injection device frame 4. , And the screw shaft 8 can be rotated by the second servomotor 9. The screw shaft 8 is screwed (engaged) with a nut 5a fixed to the support member 5. When the second servomotor 9 is driven, the screw shaft 8 rotates accordingly, and the nut 5a is rotated. It moves in the direction.

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

Next, at the time of injection, the heating cylinder 2
The first injection nozzle 21a 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 with the rotation of the screw shaft 8, and injects the resin stored in front of the screw from the injection nozzle 21a. However, in the injection device 2 having the above configuration, the first servomotor 6 is required for rotating the screw at the time of weighing, and the second servomotor 9 is required for moving the screw at the time of injection.

Therefore, there is provided an injection molding machine provided with only one servomotor for rotating the screw at the time of measuring and for moving 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 erected 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 opposing 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 protrudes from the opposite surface of the movable platen 13. I have. The screw shaft 15 is screwed into a turntable 16 rotatably mounted on the other fixed platen 10. A gear 17 is attached to the rotating disk 16. When the rotating disk 16 rotates together with the gear 17, the screw shaft 15 moves together with the movable platen 13 with the rotation.

On the other hand, the injection device 2 has a heating cylinder 21 in which the screw 20 is disposed so as to be able to move forward and backward and is rotatable, holds the heating cylinder 21 and is movably supported on the frame 3 of the injection molding machine. It has a housing 22. The screw moving member 2 is provided inside the housing 22.
The screw moving member 25 rotatably supports a screw rotation gear 26 provided at the rear end of the screw 20.

A screw shaft 30 is screwed to the rear end of the screw moving member 25, is rotatably supported by the housing 22, and is connected to a brake device 31 outside the housing 22. I have. The brake 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 servomotor 37 via a drive belt 38 outside the housing 22.
7, the transmission shaft 34 is rotated. 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 has a screw shaft 43b screwed with the fixed platen 11.

An electromagnetic clutch mechanism 44 is provided between the nozzle touch member 43 and the transmission shaft 34.
The two 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 rotation 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 is rotated.
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 are connected and rotate in the same direction.

The rotation of the nozzle touch member 43 causes the screw shaft 43b to enter the fixed platen 11, and draw the housing 22 toward the fixed platen 11. Then, 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 servomotor 37 is transmitted to the injection gear 29 via the transmission gear 36 and the like, and the screw shaft 30 is rotated. The rotation of the screw shaft 30 causes the screw moving member 2
5 is advanced, and the screw 20 advances with the advance of the screw moving member 25 to perform injection. When the injection is completed, the servomotor 37 is stopped, and at the same time, the clutch mechanism 46 is released to stop transmitting 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.

When the servomotor 37 is driven in this manner, the rotation gear 26 is rotated by the transmission gear 48, and the screw 20 is rotated with the rotation to start the measurement. At this time, the brake device 31 is operated to generate a screw back pressure. The resin supplied 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 by 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 above-described conventional injection device, the rotation of the screw at the time of metering and the advance of the screw at the time of injection can be performed by one servomotor 37.
Since the back pressure at the time of weighing is generated by 1, not only is it difficult to control the back pressure to an appropriate value, but also the durability is reduced.

The present invention solves the above-mentioned problems of the conventional injection device, and can rotate the screw at the time of weighing and advance the screw at the time of injection by one servomotor to reduce the cost. It is an object of the present invention to provide an injection device that can not only control the back pressure at the time of measurement to an appropriate value but also improve durability.

[0019]

For this purpose, in the injection device of the present invention, a screw is disposed in a heating cylinder so as to be able to move forward and backward and to rotate freely. A pressure plate is disposed between the first plate for fixing the heating cylinder and a second plate disposed opposite to the first plate so as to be able to move back and forth, and the screw is rotatable by the pressure plate. To support.

A motor is fixed to the second plate, and a first clutch is removably disposed between the motor and the first drive shaft, and the rotation of the motor is controlled by a screw via the first drive shaft. And a second clutch is removably disposed between the motor and the second drive shaft to selectively transmit the rotation of the motor to the second drive shaft. Means for converting a rotary motion into a linear motion 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 a 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 able to move forward and backward and rotate freely.
A pressure plate is disposed between the first plate for fixing the heating cylinder and a second plate disposed opposite to the first plate so as to be able to move back and forth, and the screw is rotatable by the pressure plate. To support.

Also, a motor is fixed to the second plate, a first clutch is removably disposed between the motor and the first drive shaft, and the rotation of the motor is controlled by a screw via the first drive shaft. And a second clutch is removably disposed between the motor and the second drive shaft to selectively transmit the rotation of the motor to the second drive shaft. Means for converting a rotary motion into a linear motion is provided between the second drive shaft and the pressure plate.

Therefore, when the motor is rotated at the time of weighing and the first clutch is engaged, the rotation of the motor is transmitted to the screw via the first drive shaft, and the screw is retracted while rotating. When the second clutch is engaged during injection, the rotation of the motor is transmitted to the second drive shaft, and the rotational motion is converted to a linear motion to advance the pressure plate and advance the screw.

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

[0026]

Embodiments of the present invention will be described below 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, reference numeral 21 denotes a heating cylinder in which a screw (not shown) is disposed so as to be able to move forward and backward and rotate freely, and reference numeral 21a denotes an injection nozzle provided at the tip of the heating cylinder 21. The heating cylinder 21 has a rear end fixed to a first plate 52, and the first plate 52 is fixed to the injection molding machine frame 3 (see FIG. 3). The first plate 5 is provided on the injection molding machine frame 3.
The second plate 53 is fixed opposite to the second plate 53, and a support 53 a extending forward is formed above the second plate 53.

Reference numeral 61 denotes a servomotor serving as a drive source for moving the screw forward during injection and rotating the screw during weighing, and is fixed on the support table 53a. 6
Reference numerals 2 and 63 denote first and second clutches for switching between an injection step and a metering step. The first clutch 62 is engaged and the second clutch 63 is released at the time of metering, and the first and second clutches are at the time of injection. The clutch 62 is released and the second clutch 63 is engaged.

Numeral 64 denotes a first belt pulley for transmitting the rotation of the servomotor 61 at the time of measurement, and numeral 65 denotes a second belt pulley for transmitting the rotation of the servomotor 61 at the time of injection. Reference numeral 71 denotes a ball spline, which is rotatably disposed with respect to the support table 53a to transmit rotation to the first rotary shaft 72 and to spline-fit the first rotary shaft 72 to be movable in the axial direction. (Go).

The first plate 52 and the second plate 53
A pressure plate 54 is movably disposed between the pressure plates 54, and the first rotating shaft 72 is rotatably supported on the pressure plate 54 by a bearing 55. The bearing 55 prevents relative movement in the axial direction between the first rotation shaft 72 and the pressure plate 54. At the rear end of the screw, a screw rotating shaft 56 is provided,
The rotation transmitted to the first drive shaft 73 is transmitted to the screw. The first drive shaft 73 is connected to the pressure plate 5
4 to be freely rotatable.

Therefore, when the second clutch 63 is released and the first clutch 62 is engaged during measurement, the rotation of the servomotor 61 is controlled by the ball spline 71, the first rotating shaft 72, the first belt pulley 64, It is transmitted to the screw via the drive shaft 73 and the screw rotating shaft 56, and rotates backward while rotating the screw. Therefore, the resin injected from the hopper advances with the retreat of the screw, and is accumulated in front of the screw. At this time, as the screw retreats, the pressure plate 54 that rotatably supports the screw rotation shaft 56 and the first drive shaft 73 also retreats.

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

Therefore, when the first clutch 62 is released and the second clutch 63 is engaged at the time of injection, the rotation of the servo motor 61 is transmitted to the ball screw 57 via the second belt pulley 65. When the ball screw 57 rotates, the ball nut 58 is linearly moved with the rotation.
4. The screw is transmitted to the screw via the first drive shaft 73 and the screw rotation shaft 56 to advance the screw. As the screw advances, the resin stored in front of the screw at the time of measurement is injected from the injection nozzle 21a, and is filled in a cavity of a mold (not shown).

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

A back pressure cylinder 67 is provided to apply a back pressure to the screw that moves backward during measurement.
In this embodiment, the back pressure cylinder 67 will be 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 provided inside the back pressure cylinder 67.
7a is slidably disposed, and the pressure plate 5
An oil chamber 67b is formed on the fourth side. A guide bar 77 is fixed to both sides of the piston 67a. The front end of the guide bar 77 is fixed to the first plate 52, and the rear end of the guide bar 77 is fixed to the second plate 53.

Reference numeral 78 denotes a hydraulic pressure source for applying pressure to the back pressure cylinder 67; 79, a filter; 80, a pressure reducing valve for supplying a constant pressure oil to an oil chamber 67b of the back pressure cylinder 67; Is a switching valve that takes the A position and the B position, 8
Reference numeral 2 denotes a silencer 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 at the position A, the oil in the oil chamber 67b is drained, and no back pressure is applied. Further, when the switching valve 81 is placed at the position B, the oil decompressed by the pressure reducing valve 80 is supplied into the oil chamber 67b, and the pressure plate 54 is pressed toward the first plate 52 to apply a back pressure to the screw.

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

[0037]

As described above in detail, according to the present invention, the screw is disposed in the heating cylinder so as to be able to move forward and backward and freely rotate. A pressure plate is disposed between the first plate for fixing the heating cylinder and a second plate disposed opposite to the first plate so as to be able to move back and forth, and the screw is rotatable by the pressure plate. To support.

A motor is fixed to the second plate, and a first clutch is removably disposed between the motor and the first drive shaft. The rotation of the motor is controlled by a screw via the first drive shaft. And a second clutch is removably disposed between the motor and the second drive shaft to selectively transmit the rotation of the motor to the second drive shaft. Means for converting a rotary motion into a linear motion is provided between the second drive shaft and the pressure plate.

Therefore, only by disposing one motor, the screw can be rotated backward by rotating the screw by engaging the first clutch at the time of metering, and the screw can be moved backward by engaging the second clutch at the time of injection. It can move forward and reduce costs. Further, a back pressure cylinder is fixed to the pressure plate, and the pressure plate is urged toward the first plate by a fluid pressure to apply a back pressure to the screw. Therefore, not only can the back pressure at the time of measurement be controlled to an appropriate value, but also the durability can be improved.

[Brief description of the 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 a conventional injection molding machine.

[Explanation of symbols]

 Reference Signs List 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

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁶ , DB name) B29C 45 / 17,45 / 46-45 / 53,45 / 58-45/62

Claims (1)

(57) [Claims] (A) a heating cylinder; (b) a screw disposed in the heating cylinder so as to be able to move forward and backward and rotatably; (c) a first plate for fixing the heating cylinder; A) a second plate disposed opposite to the first plate; and (e) a pressure plate disposed between the first plate and the second plate so as to be able to move back and forth and rotatably supporting the screw. (F) a motor fixed to the second plate; and (g) a first clutch disposed to be freely disengageable and selectively transmitting the rotation of the motor to the screw via a first drive shaft. (H) freely disengaged,
A second drive shaft for selectively transmitting the rotation of the motor to a second drive shaft;
A clutch; (i) means for converting a rotary motion into a linear motion between the second drive shaft and the pressure plate; and (j) a pressure plate which is fixed to the pressure plate and which is moved toward the first plate by fluid pressure. An injection device comprising: a back pressure cylinder for urging and applying a back pressure to the screw.