JPH01215527A - Braking method for injection device and equipment therefor - Google Patents

Abstract

PURPOSE:To suspend a longitudinal movement of an injection unit precisely at an appropriate position and the position is held surely, by combining a braking type brake and holding type brake with the injection unit. CONSTITUTION:An injection unit 4 moves forward through a spring 13 and a nozzle 11 of a cylinder assembly 10 comes into contact with a mold fitted to a stationary platen 6. A rotation of a motor is kept on even after the contact and a ball nut part 14 is moved forward by compressing the spring 13. Simultaneously with the above a dog 20 also keeps forward movement on and when the nozzle 11 arrives at a switch S1 on an established position corresponding to an appropriate value of force coming into contact with the mold, which is detected by the switch Sl and a signal is transmitted to a control device 30. Electric power of a braking type brake 22 of control equipment 17 is interrupted, in the control device 30. Then after the lapse of suspension securing hours (t), electric power of a holding type brake 23 is interrupted. The injection unit 4 is suspended under an appropriate state and held. As the holding type brake 23 is actuated after suspension of the injection unit 4, damage is not generated on a braking surface.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention This invention relates to a braking method and apparatus for stopping and maintaining the back and forth movement of an injection unit in an injection molding machine at a proper position.

The injection unit in the prior art injection molding machine is moved back and forth relative to the fixed platen of the mold clamping unit when it is necessary to seal for nozzle touch, sprue break, or cylinder assembly replacement.

This movement is performed by a nozzle touch mechanism, and this mechanism is equipped with a braking device to stop the injection unit at a proper position and maintain that position during each back and forth movement.

This type of braking device brakes the rotation of the drive shaft in the nozzle touch mechanism, and there are two types: a braking type and a holding type.

The braking type is suitable for stopping the rotation of the shaft, and because it is usually dynamic friction that contributes to braking, the braking surface is made of a material that does not have a large force but has excellent toughness. . The holding type is suitable for keeping the drive shaft stationary, and because it is static friction that contributes to braking, the braking surface is made of a material that has a large frictional force but is more brittle than the brake type. .

The braking device provided in the conventional nozzle touch mechanism is only one of the above-mentioned braking type and holding type brake, which stops the rotation of the drive shaft and further maintains the stopped state.

Therefore, in those using a braking type, a large one is used in order to obtain the large holding force necessary after the rotation of the drive shaft has stopped E. Furthermore, in the case of a retaining type brake, the drive shaft may be stopped for a shorter time than the set value during operation, resulting in distortion of various parts or damage such as chipping of the material of the braking surface.

Furthermore, the nozzle touch mechanism usually has a buffer spring interposed between it and the extruder base to prevent damage to the nozzle and mold due to excessive pressing force after the nozzle is touched. If the holding brake is not activated at the correct timing, the drive shaft will rotate in the opposite direction due to the return bias from the spring mentioned above and the inertia of the injection unit itself, making it impossible to stop the injection unit at the proper position. Conventionally, it has been difficult to operate the holding brake at this timing.

Problems to be Solved by the Invention An object of the present invention is to provide a braking method and a braking device for an injection unit that can accurately stop the back and forth movement of the injection unit at a proper position and reliably maintain that position.

Means for Solving the Problems - Braking Method for Injection Unit - After stopping the movement of the injection unit by the υ1 dynamic brake, the stopped state of the unit is maintained by the holding brake.

Braking device for one injection unit - A braking type brake and a holding type brake are provided on the drive shaft of the nozzle touch mechanism, and a stop securing time is set after the braking type brake is activated based on a signal to stop the rotation of the drive shaft. control means for actuating the holding brake.

The action braking type brake stops the rotation of the drive shaft in the nozzle touch mechanism to stop the injection unit at a proper position, and the holding type brake prevents rotation of the stopped drive shaft and maintains the injection unit at a proper position.

EXAMPLE Hereinafter, an example apparatus to which the present invention is applied will be described.

In FIG. 2, an injection molding machine 1 includes a mold clamping unit 3 and an injection unit 4 on a main machine frame 2, and both units are connected by a nozzle touch mechanism 5.

The mold clamping unit 3 is equipped with a fixed platen 6, and the injection unit 4 is constructed on an extruder base 7, and is movable back and forth on a rail 8 fixed on the main machine frame 2 by rollers 9. There is. As shown in FIG. 1, the nozzle touch mechanism 5, whose reference numeral 10 is a cylinder assembly and 11 is a nozzle at its tip, is slidable in the front and back direction in the through hole 12 of the extruder base 7, and is equipped with a spring 13. A pole nut part 14 attached through the pole nut part 14, a pole screw 15 screwed thereto and extending toward the fixed platen 6, a nozzle touch servo motor (hereinafter simply referred to as motor) M, and a braking device 17 provided on its drive shaft 16. A gear 18 is fixed to the fixed platen 6 side of the ball screw 15, and a gear 19 is fixed to the drive shaft 16, and both gears mesh with each other. is configured at a fixed position on the fixed platen 6 side of the main machine frame 2.

Symbols S1 and S2 are proximity switches, the proximity switch S1 is for detecting the proper nozzle touch pressure position dog 20 arranged at the rear end of the pole nut 14, and the proximity switch S2 is for detecting the proper retreat position dog 21 of the injection unit 4. It is something.

The braking device N17 includes a braking type brake 22 and a holding type brake 2.
These brakes 22 and 23 are all ordinary disk-type electromagnetic brakes, and each rotor 24 and 25 are spline-fitted to the drive shaft 16, and stators 26 and 27 that are fixed to the case side and do not rotate. are facing each other,
Normally, the rotors 24, 25 are pressed against the stators 26, 27 by the springs 28, 29, respectively, to exert braking force, but when electric power is supplied, the rotors 24, 25 are pressed against the stators 26, 27 by the springs 28, 29, respectively.
29 and is pulled away from the stator 26, 27 to release the braking force.

The main difference in the construction of the braking type brake 22 and the holding type brake 23 is only the nature of the material attached to the braking surfaces of the rotor 24.25 and stator 26.27, as described above.

Reference numeral 30 is a control means that controls the entire injection molding process, and the injection unit 4, such as the nozzle touch,
For forward and backward movement, use the proximity switch S1 or S2.
Detection signals of dogs 20 and 21 from , i.e. drive@1
When there is a signal to stop the rotation of the drive shaft 16, the electric power to the till dynamic brake 22 is first cut off and the rotation of the drive shaft 16 is changed by υ1, and the stop securing time t required for the drive shaft 16 to completely stop is determined. It has the ability to execute the procedure of cutting off the power to the holding type brake 23 and exerting the holding braking force after a certain period of time has elapsed.

The above-mentioned stopping time t is usually about 1 to 2 seconds, but it varies depending on the type and standard of the brake or the properties of the material that makes up the braking surface, and it is necessary to experimentally determine a sufficient time within an allowable range. There is.

In the state shown in FIG. 1, when a nozzle touch command is received from the control device 30, first the holding brake 2 of the braking device 17
3, the brake 23 is released, and the brake 22 is subsequently released in the same manner. Next, the drive shaft 16 is rotated by the motor M, and the ball nut portion 14 is drawn toward the fixed platen 6 by the gear 19° 18 and the ball screw 15.
The injection unit 4 moves forward via the spring 13, and the nozzle 11 of the cylinder assembly 10 comes into contact with the mold attached to the fixed platen 6, resulting in a nozzle touch. Even after a nozzle touch occurs, the motor M continues to rotate, and the ball put portion 14 compresses the spring 13 to move forward, thereby applying a nozzle touch force. At the same time, the dog 20 also continues to move forward, and when the proximity switch $1 reaches the setting position where the nozzle touch force is appropriate, the switch S1 detects this and transmits a signal to the control means 30. Then, the control means 30 controls the braking type brake 22 of the braking device 17 as described above.
First, the power to the holding brake 23 is cut off, and then after the stop securing time t has elapsed, the power to the holding brake 23 is cut off. This results in
The injection unit 4 is stopped in a state where a J positive nozzle touch force is applied, and this state is maintained. Even if the Itll power of the braking type brake 22 is insufficient to maintain the stopped state of the drive shaft 16, it is possible to prolong the temporary stopped state (within the stop securing time), so the holding type The timing of braking the drive shaft 16 by the brake 23 is not changed.

The same procedure is followed when the injection unit 4 is moved back and stopped due to a sprue break or the like. however,
In this case, motor M reverses and proximity switch S2 switches to dog 2.
It is started by a signal that detects 1.

Note that the holding brake 2 is used to maintain the stopped state of the drive shaft 16.
The braking force of only 3 can be sufficient, but when releasing the braking force, the braking type brake 22 is also operated,
It is preferable to prevent the drive shaft 16 from starting to rotate rapidly when the holding brake 23 is released.

Further, the drive shaft on which the braking device 17 is provided may be any drive shaft in the nozzle touch mechanism 5, and further,
The brake of the braking device may be of two types, a braking type and a holding type, and is not limited to a disc-shaped electromagnetic brake.

Advantages of the Invention By employing a braking type brake, there is a margin in the operating timing of the holding type brake, and it is easy to hold the injection unit in a proper position.

Since the holding brake is activated after the injection unit has stopped, there is little damage to the braking surface.

[Brief explanation of the drawing]

FIG. 1 is a mechanical front view, and FIG. 2 is a partially cutaway front view. DESCRIPTION OF SYMBOLS 1... Injection molding machine, 2... Main machine frame, 3... Mold clamping unit, 4... Injection unit, 5... Nozzle touch mechanism, 6... Fixed platen, 7... Extruder pace, 8...Rail, 9...Roller, 10.
... Cylinder assembly, 11... Nozzle, 12.
...Through hole, 13...Spring, 14...Pole nut part, 15...Ball screw, 16...Drive shaft,
17... Braking device, 18° 19... Gear, 20.2
1... Dog, 22... Braking type brake, 23...
Holding type brake, 24.25...〇-ta, 26.27
... Stator, 28.29 ... Spring, 30 ... Control means, 81.82 ... Proximity switch. Patent applicant: FANUC CORPORATION Figure 2 5 9B7 2

Claims (2)

[Claims] (1) A method for braking an injection unit, which comprises stopping the movement of the injection unit using a braking type brake, and then maintaining the stopped state of the unit using a holding type brake. (2) A braking-type brake and a holding-type brake are provided on the drive shaft of the nozzle touch mechanism, and after the braking-type brake is activated based on a signal to stop the rotation of the drive shaft, the holding-type brake is applied after a stop securing time has elapsed. A braking device for an injection unit, comprising a control means for operating the injection unit.