JPH0248913A - Motor-driven injection device - Google Patents

Abstract

PURPOSE:To contrive universal adjustment control of an advance motion speed of a screw of an injection molding machine by bearing a high load at the time of measurement, by a method wherein a rotary transmission member for measurement of a material is provided on a shaft converting turning force of a servomotor into a linear motion. CONSTITUTION:When injection is completed, a servomotor is suspended by a command and at the same time connection with a gear 39 is disconnected by actuating a clutch mechanism 41. Then a transmission gear 38 and transmission shaft 37 are turned together by actuating a clutch mechanism 40. When the servomotor is turned reversely again, a screw 20 is turned and a material is supplied within an injection heating cylinder 21. Backward movement force is generated on the screw 20. With this backward movement force, a screw holding member 25 is pressed and turning force in the direction opposite to that at the time of forward movement of the screw is generated on a screw shaft 30. A brake 31 is actuated at the same time and the screw shaft 30 is braked. Measurement of a material is performed while generating back pressure.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an injection device for injecting synthetic resin using an electric motor.

[Prior Art] As an electric injection device, the one described in Japanese Utility Model Publication No. 39-10424 is known.

This injection device rotatably connects a screw shaft to a holding member at the rear end of the plunger, and a commonly used electric motor rotates a screw receiving member screwed into the screw shaft at a fixed position to hold the holding member together with the screw shaft. It consists of a structure that moves forward and backward.

[Problem to be solved by the invention] A normal electric motor used in such a conventional device is
It is unsuitable for starting, stopping, and rapid acceleration/deceleration control of electric motors, and is difficult to use for injection systems that require high-speed response.

In addition, torque control is difficult, high-precision speed control over a wide range from low speed to rated speed is not possible, and there is no means to measure material by rotating a screw, so it is difficult to apply it as an injection device. It was impossible.

This invention was devised to solve the above-mentioned problems with electric injection devices, and its purpose is to achieve high speed response, high precision speed control, torque control, etc. while using an electric motor as an injection drive source. It is an object of the present invention to provide an electric injection device which is excellent and can also perform injection by rotating a screw.

[Means for Solving the Problems] The features of this invention according to the above-mentioned objects include a screw of an injection heating cylinder having an extension shaft at the rear end, a screw that is rotatably held via the extension shaft, and a screw that moves forward and backward together with the screw. A moving holding member is screwed together with a screw receiving member provided on the screw holding member via a ball, and the rotational force from the injection drive source is converted into a linear motion for advancing the screw by the screw receiving member. The electric injection device comprises a screw shaft at a position, a rotation transmission member is provided on the extension shaft, and the screw is rotated by a servo motor via the rotation transmission member to perform metering.

[Function] In the above configuration, the rotational force of the servo motor is transmitted to the screw, and when the screw rotates, the material is transferred into the injection heating cylinder. The backward force generated in the screw due to the transfer of the material generates a rotational force in the screw shaft in the opposite direction to the forward movement of the screw through the screw holding member, and the material is measured.

The present invention will be explained in detail below with reference to embodiments shown in the drawings.

[Example] In the figure, 1 indicates a mold clamping device, and 2 indicates an injection device. The mold clamping device 1 includes a tie bar 12 installed on a pair of fixed plates 10 and 11 on a machine stand 3, and a movable plate 13 movably attached to the tie bar 12. One of the above fixed I! A11 and movable! 1
A mold 14, 14 is provided on the surface facing the movable plate 13, respectively, and a screw shaft 15 is provided protruding from the surface opposite the movable plate 13. This screw shaft 15 is screwed into a rotary disk 16 rotatably attached to the other stationary plate 10 via balls, and a gear 17 is attached to the rotary disk 16. Rotate above! When the screw shaft 16 rotates, the screw shaft 15 moves together with the movable platen 13 by the screw lead.

The injection device 2 is an injection heating n21 equipped with a screw 20.
and a housing 22 on the machine base that also serves to hold the injection heating cylinder 21. Inside the housing 22, there is a rear end of the screw 20 and a pair of support shafts 24.24 installed on both sides in parallel with the screw. It is slidably mounted.

Further, an extension shaft 27 having a gear 26 is connected to the rear end of the screw 20, and the end of the extension shaft 27 is rotatably connected to the screw holding member 25.

Furthermore, the screw receiving member 28 provided at the rear of the screw holding member 25 has a screw shaft 3 which is rotatably held on the housing wall 22a and is integral with a shaft portion 30a having a gear 29.
0 is screwed in via a ball, and the outer end of the shaft portion 30a is connected to a brake device 31 fixed to the housing wall portion 22a. This brake device 31 is equipped with a hysteresis brake inside.

This hysteresis brake consists of three parts: a field, a rotor, and a cup. When the field containing the excitation coil is magnetized by energization and a magnetic field is generated between the outer and outer magnetic poles of the rotor, the cup placed in the magnetic field also It is magnetized and has a structure in which the rotor and cup are magnetically connected, and is commonly available on the market. 32 is a transmission shaft on the mold clamping device side, 33 is a transmission shaft on the injection device side, and as shown in FIG. A transmission gear 35 is provided close to the stationary platen 10 and meshed with the gear 17. Further, the transmission shaft 32 is connected to the transmission@36 via a joint 36a having a spline, and the transmission shaft 36 is connected to the transmission shaft 36 through a joint 36a having a spline.
3 and are connected to each other via an electromagnetically actuated clutch mechanism 34 so as to be able to freely approach and separate.

Further, the transmission shaft 33 is rotatably supported in the lower part of the housing 22 together with another transmission shaft 37, and the transmission shaft 33.
Transmission gears 38 and 39 that mesh with the gears 26 and 29, respectively, and a plurality of electromagnetically actuated clutch mechanisms 40 and 41 that rotate and stop the teeth jjz are provided on the transmission shaft 37. 22 and connected to a servo motor 42 via a drive belt 43.

Note that 44.45 is a driving gear provided on the transmission shaft 33.37, 46 is a screw shaft for nozzle touch, and 47 is a screw shaft 46.
It is a clutch.

In the example shown in FIG. 5, the support shafts 24 and 24 are rotatably installed, and the insides thereof are screw shafts 24a, 24a, and screw receiving members 28 are provided at both ends of the screw holding member 25.
．． 28 is provided and screwed into the screw shafts 24a, 24a through balls, respectively, and the support shafts 24.24
Further, gears 29a, 29a are provided which mesh with the gear 29, and the rotation of the gear 29 is transmitted to the support shaft 24, 24 via the gears 29a, 29a, and the screw holding member 25 is moved forward and backward together with the screw 20 by torsion. It consists of a moving structure.

Next, the injection molding process will be explained.

With the clutch mechanism 34 connecting the transmission shafts 32 and 33, the servo motor 42 is rotated forward. At this time, on the injection device 2 side, the transmission gears 38 and 39 are set in a free state by the operation of the clutch mechanisms 40 and 41.

The rotary disk 16 is rotated by the transmission shaft 32, the transmission gear 35, and the gear 17, and the screw @15 is fed out. As a result, the movable platen 13 moves forward, the molds 14 and 14 are closed, and even stronger mold clamping is performed. When the mold clamping pressure reaches a predetermined pressure, the brake 48 is activated to fix the transmission shaft 32, and the clutch mechanism 34 is further activated to disconnect the transmission shaft 33.

Further, on the injection device side, the clutch mechanism 41 is activated by the command, and the transmission gear 39 is rotated together with the transmission shaft 33. As a result, the screw shaft 30 is rotated together with the gear 29, and the screw holding member 25 is advanced by the screw lead. This screw holding member 25 includes an extension shaft 27 at the rear end of the screw.
Since this is a bearing, the screw 20 also moves forward together to perform injection.

When the injection is completed, the servo motor 42 is stopped by the command, and at the same time, the clutch mechanism 41 is operated to disconnect the gear 39. Next, the clutch mechanism 40 operates and the transmission gear 3
8 is made to rotate φλ together with the transmission shaft 37. Then, when the servo motor 42 rotates in the reverse direction again, the screw 20 rotates and the material is transferred into the injection heating cylinder 21. A retraction force is generated in the screw 20 by the transfer of the material, and the retraction force presses the screw holding member 25, thereby generating a rotational force in the screw shaft 30 in a direction opposite to that when the screw advances.

At the same time, the brake device 31 is actuated to apply a brake force to the screw shaft 30, so that the material is measured while generating so-called screw back pressure.

When the weighing is completed, on the mold clamping mechanism side, the electromagnetic brake 48 is released and the clutch mechanism 34 is activated to connect the transmission shaft 32 to the transmission shaft 33 again. Further, by rotating the servo motor 42 in the reverse direction, the screw shaft 15 rotates in the reverse direction to open the mold, completing one cycle of injection molding.

[Effects of the Invention] As described above, the present invention includes a screw of an injection heating cylinder having an extension shaft at the rear end, and a holding member that rotatably holds the screw via the extension shaft and moves forward and backward together with the screw. , a screw shaft in a fixed position that is screwed together via a ball with a screw receiving member provided on the screw holding member, and converts the rotational force from the injection drive source into a linear motion for advancing the screw by the screw receiving member. and a rotational transmission member for measuring the material is provided on the extension shaft, and a servo motor is provided to rotate the screw via the rotational transmission member.
Although the screw is rotated by an electric motor, it has the advantages of being durable against high loads during metering, meeting the demands for high viscosity adjustment characteristics, and being easy to control torque.

[Brief explanation of the drawing]

The drawings show one embodiment of the electric injection device according to the present invention, and FIG. 1 is a side view of the injection molding machine, FIG. 2 is a cross-sectional plan view of the injection device, and FIG. 3 is a longitudinal cross-section of the housing portion. 4 is a cross-sectional plan view of the lower portion of the housing, FIG. 5 is a cross-sectional plan view of another embodiment of the injection device, and FIG. 6 is a vertical cross-sectional view of the housing portion of FIG. 5. 1... Mold clamping device 20... Screw 24... Support shaft 26... Gear 28... Screw receiving member 30... Screw shaft 2... Injection Device 21...Injection heating cylinder 25...Screw holding member 27...Extension shaft 29...Gear 42...Servo motor Applicant for the current review Applicant: Autumn, agent of Ususei Jushi Kogyo Co., Ltd. Teruo Rakugai. 6.1

Claims (1)

[Claims] A screw of an injection heating cylinder having an extension shaft at the rear end, a holding member that rotatably holds the screw via the extension shaft and moves forward and backward together with the screw, and a screw receiving member provided on the screw holding member. Screw together through the ball,
It consists of a screw shaft in a fixed position that converts the rotational force from the injection drive source into a linear motion for advancing the screw by the screw receiving member, and the extension shaft is provided with a rotation transmission member for measuring the material, and the rotation transmission is An electric injection device characterized by comprising a servo motor that rotates a screw via a member.