JPH0248914A - 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 a method wherein a mechanism transmitting turning force of a screw shaft by a servomotor to the screw is made into a slide mechanism. CONSTITUTION:A clutch mechanism 41 is actuated and a transmission gear 39 is turned along with a transmission shaft 33. With this construction, a screw shaft 30 is turned along with a gear 29 and turning force is converted into thrust force of a linear direction with a screw lead through screwing-on of a screw receiving member 28 with a screw. With this thrust force, a screw holding member 25 is guided by a support shaft 24 and moves forward while sliding. Since the screw holding member 25 moves forward while sliding on the support shaft 24, screw 20 provided by connecting with the screw holding member 25 can move forward smooth. Torque control and speed control of a screw covering a wide area become possible.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to an injection molding machine using a servo motor as an injection drive source.

[Prior art 1 An injection device using an electric motor as an injection drive source was developed in Utility Model Publication in 1973-10.
It is known from No. 424.

This injection device has a sliding plate supported by a pair of tie bars, a plunger is connected to the front of the sliding plate, and a screw shaft with a keyway in the axial direction is connected to the rear of the sliding plate, and the screw shaft rotates at a fixed position. A worm wheel is provided with a key that fits into the key groove, and the worm wheel, pulley, and screw shaft convert the rotational force generated by the electric motor into the thrust force of the plunger.

[Problems to be Solved by the Invention] Such an injection device requires a resistor that prevents the rotation of the screw shaft via a worm wheel, and has a complicated structure such as requiring a keyway on the screw shaft, which increases the torque. There were also problems with control, and it was difficult to put it into practical use as it was.

The object of the present invention is to provide an electric injection device with a new configuration that has a simpler structure than the conventional device described above, is capable of converting rotational force into a thrust force of a screw, and has good responsiveness.

[Means for Solving the Problems] The present invention according to the above object is characterized by a screw holding member that rotatably holds the screw in the injection heating cylinder via an extended shaft at the rear end and has a screw receiving member at the rear. , a pair of support shafts on both sides that horizontally support the screw holding member, and the screw receiving member and the ball are screwed together through the ball. The present invention is an electric drive device consisting of a fixed screw shaft that converts rotational force from a servo motor into thrust force of the screw by means of the screw receiving member, and a rotation transmission member fixed to the screw shaft.

[Function] In the above configuration, when the screw shaft rotates, the screw receiving member side that is integrated with the screw holding member is pushed out along the screw lead, and the screw holding member moves forward with the screw using the support shaft as a guide. do.

As a result, the rotational force by the servo motor is converted into the thrust force of the screw, and injection is performed.

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

In the figure, 1 indicates the mold clamping position A, and 2 indicates the injection device. Mold clamping device 1
The tie bar 12 is installed on a pair of fixed plates 10 and 11 on the machine base 3, and the movable plate 13 is movably attached to the tie bar 12. Above - 10,000 fixed plates 11 and movable plates 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 reflective surface of the movable plate 13. This screw shaft 15 is screwed through a ball into a rotary disk 16 rotatably mounted on the other stationary plate 10, and a T-helical gear 17 is attached to the rotary disk 16. When the rotary disk 16 rotates, the screw shaft 15 moves together with the rotary disk 13 by twisting.

The injection device 2 includes an injection heating cylinder 21 containing a screw 20.
and a housing 22 on the machine base that also serves to hold the injection heating cylinder 21. There are scratches inside the housing 22:
There is a pair of support shafts 24.24 installed on both sides parallel to the rear end of 120 and the screw.
A screw holding member 25 is attached so as to be movable in the front and rear directions.

Further, an extension shaft 27 having a gear 2G 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 @3 which is rotatably held on the housing wall 22a and is integral with the shaft portion 30a having the 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 electricity and a magnetic field is generated between the outer and outer magnetic poles of the rotor, it is exposed to the magnetic field. The rotor and the cup are also magnetized and have a structure in which the rotor and the cup are magnetically connected, and are commonly commercially available. 32 is a transmission shaft on the mold clamp Hfa side marked -F, 33 is a transmission shaft on the injection device side,
As shown in FIG. 1, the transmission shaft 32 is rotatably supported at the lower part of the stationary plate 10 and 11, and has a transmission tooth width 35 that is close to the stationary plate 10 and meshes with the gear 17.

Further, the transmission shaft 32 has a splined joint 36a.
The transmission shaft 36 is connected to the transmission shaft 33 via an electromagnetically actuated clutch mechanism 34 so that the transmission shaft 36 can be freely approached and separated from the transmission shaft 33 .

The transmission shaft 33 is rotatably supported in the lower part of the housing 22 together with another transmission shaft 37.
371 and the tooth width 26 and the transmission that mesh with the two respectively @
Gears 38 and 39 and a plurality of electromagnetically actuated clutch mechanisms 40 and 41 for rotating and stopping the gears are provided, and the transmission shaft 37 is fixed to the housing 22 and a servo motor 42 is connected via a drive belt 43. Please let me know.

Note that 4.4.45 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 4.
6 clutch.

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 left 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. Upon this fastening, the movable platen 13 moves forward to close the molds 14 and 14, and the molds are further strongly clamped. 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 @33. As a result, the screw shaft 30 rotates together with the gear 29, and the rotational force is converted into a thrust force in the linear direction by the screw lead caused by the screw engagement with the screw of the screw receiving member 28, and the screw holding member 29
5 is guided by the support shaft 24 and moves forward. Since an extension shaft 27 at the rear end of the screw is supported on this screw holding member 25, the screw 20 also moves forward together to perform injection.

) When output 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 is operated to cause the transmission gear 38 to rotate 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. The retreating force generated in the screw 20 due to the transfer of the material is transferred to the screw shaft 30 via the screw holding member 25.
A rotational force is generated in the opposite direction to when the screw moves forward.

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 @33 again. Further, by rotating the servo motor 42 in the reverse direction, the screw shaft 15 is rotated 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 holding member that rotatably holds the screw in the injection heating cylinder via the extended shaft at the rear end and has a screw receiving member at the rear, and the screw holding member. A pair of support shafts on both sides that horizontally support the member, and a fixed position that is screwed together with the screw receiving member through the ball to convert the rotational force from the servo motor into the thrust force of the screw J with the screw receiving member. Since the electric injection device is constructed from a screw shaft and a rotational transmission member fixed to the screw shaft, there is no need for a conventional resistor, and since the screw is moved forward only by the rotation of the screw shaft, There is no waste in driving force, and the ball screw allows for smooth movement of the screw holding member, resulting in good transmission efficiency, easy torque control, high-precision speed control, and the simple structure means fewer breakdowns. It has the following advantages.

[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. FIG. 4 is a cross-sectional plan view of the lower portion of the housing. 1... Mold clamping device, 2... Injection device, 20... Screw, 21...
- Injection heating cylinder 24... Support shaft 25... Screw holding member 27... Extension shaft, 28... Screw receiving member 29... Gear 30. ...screw shaft 42...servo motor. Patent applicant: Nissei Jushi Kogyo Co., Ltd. Representative: Teru Hitoaki Moto Yugai 1 person

Claims (1)

[Claims] A screw holding member that rotatably holds the screw in the injection heating cylinder via an extension shaft at the rear end and has a screw receiving member at the rear, and a pair of support shafts on both sides that horizontally support the screw holding member. , a fixed-position screw shaft that is screwed together with the screw receiving member through a ball and converts rotational force from the servo motor into thrust force of the screw by the screw receiving member; and a rotation transmission member fixed to the screw shaft. An electric injection device characterized by comprising: