JPH0710550B2 - Product ejector of injection molding machine - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a product ejecting device for ejecting a molded product by ejecting it from a mold in an injection molding machine.

2. Description of the Related Art As a projecting device for projecting a product from a mold, there has been a mechanical projecting device, a hydraulic projecting device, and the like.

The mechanical ejector is of a type in which when the movable platen is retracted and the mold is opened, the stroke adjusting bolts, etc. provided on the fixed platen press the ejector plate and eject the ejector pin to take out the product. The ejecting device is a device for ejecting a product by driving an ejector plate by a hydraulic cylinder to eject an ejector pin.

On the other hand, in recent years, a system has been developed in which a ejector plate is driven by a servo motor to eject an ejector pin to take out a product (for example, Japanese Utility Model Laid-Open No. 61-10825).

FIG. 2 is a cross-sectional view of a main part of such a conventional servo motor driven type product ejecting apparatus. 20 is a movable platen,
Reference numeral 21 denotes a servomotor attached to the movable platen 20, and a ball screw 22 is rotatably fixed to the movable platen 20. Timing at which the ball screw 22 and the motor shaft of the servomotor 21 are fixed to each other. Gears 23,24
A timing belt 25 is hung between them. Also, a ball nut 26 is screwed into the ball screw 22,
The ball nut 26 is fixed to an ejector plate 27 to which an eject pin 28 is fixed.

When the servomotor 21 is normally rotated in such a configuration, the ball screw 22 rotates through the timing gear 23, the timing belt 25, and the timing gear 24,
The ball nut 26 that is screwed with the 22 moves in the axial direction of the ball screw 22 in accordance with the rotation of the ball screw 22, moves the ejector plate 27 and the ejector pin 28 to the right in FIG. It will stick out. Further, if the servo motor 21 is rotated in the reverse direction, the ejector pin 28 will move backward (to the left in FIG. 2).

Problems to be Solved by the Invention In the product ejecting apparatus driven by the conventional servomotor as described above, the servomotor is rotated forward and backward to project and retract the ejector pin. When the product is ejected by projecting a plurality of times, it is necessary to control the servo motor many times. For example, in the case of performing the ejecting operation twice, first, the forward rotation is accelerated, the deceleration is stopped at the set ejecting stroke position, then the reverse rotation is accelerated, the deceleration is stopped at the ejecting start position, and the same operation is performed again. It needs to be done. Therefore, the acceleration and deceleration control of the servo motor needs to be performed four times in one protrusion operation, and a total of 8 times in two protrusion operations.
It is necessary to perform acceleration / deceleration control once. If a lot of acceleration / deceleration control is performed in this way, there is a drawback that energy loss is increased.

Therefore, an object of the present invention is to reduce the number of times of acceleration / deceleration control and energy loss in a product ejection device driven by a servomotor.

Means for Solving the Problems A rotary body driven by a servomotor is provided, and a link is pivotally mounted between one end of the rotary body and an ejector plate to which the ejector pin is fixed, so that the ejector pin is driven by the servomotor. The above-mentioned problem was solved by making the protrusion freely retractable.

Action When the servomotor is driven, the rotating body rotates, and one end of the link pivotally attached to one end of the rotating body rotates together with the rotating body, but the other end of the link pivots to the ejector plate to reciprocate. The ejector plate is moved in a reciprocating manner, and as a result, the ejector pin is projected and retracted. The ejector pin reciprocates once for one revolution of the rotating body, that is, ejects once and returns to the ejecting start position. Therefore, when ejecting operation is performed a plurality of times, the rotating body should be rotated a plurality of times in succession. Of course, no matter how many times the protrusion is made, the servomotor need only be accelerated and decelerated twice. That is, it is only necessary to accelerate the rotation of the rotating body from the protruding start position, rotate the rotating body one or more times, perform the projecting operation once or more, and then decelerate when returning to the projecting start position and stopping. Therefore, energy loss can be reduced.

Embodiment FIG. 1 is a plan view of an embodiment of the present invention, in which 1 is a movable platen, 2 is an ejector plate, and 3 and 3 are fixedly attached to an ejector plate 2 and penetrate a hole provided in the movable platen 1. It is an ejector pin. Reference numeral 4 denotes a servo motor fixed to a mounting plate 8 fixed to a movable platen, and a gear 6 is fixed to a motor shaft 5 of the servo motor 4. Reference numeral 7 denotes a gear as a rotating body, which meshes with the gear 6 and is rotatably fixed to a shaft 12 fixed to the mounting plate 8. A pin 9 is fixed to the gear 7, and one end of a link 10 is pivotally attached to the pin 9. Also, the link
The other end of 10 is a pin fixed to the ejector plate 2
It is pivotally attached to 11. Incidentally, 13 and 13 are guide lots for guiding the ejector plate 2.

In the state before the operation of the product ejector, the gear 7
Has the pin 9 on the leftmost side in FIG. That is, the pin 9, the shaft 12, and the pin 11 are on the same line, and the ejector plate 2 and the ejector pin 3 are in the retracted position, and this position is the protrusion start position.

When the product is ejected from the mold, when the servo motor 4 is driven and the gear 6 is rotated, the gear 7 meshed with the gear 6 is also rotated, and as a result, the pin 9 fixed to the gear 7 is also centered on the shaft 12. 1. The ejector plate 2 is moved to the right in FIG. 1 through the link 10 and the pin 11 to project the ejector pin 3 and the gear 7 is rotated once to project the ejector pin 3 and 3 once. Thus, the ejecting operation can be performed once. Further, in order to perform the ejecting operation twice or more, simply by continuously rotating the servo motor 4 and rotating the gear 7 the required number of times, the ejecting operation can be performed the required number of times. .

In this case, the acceleration / deceleration of the servo motor 4 need only be two times of acceleration / deceleration, that is, acceleration at the start of the protrusion operation and deceleration at the end of the protrusion operation, no matter how many times the protrusion operation is performed. Therefore, the energy consumption associated with the acceleration / deceleration operation can be minimized.

In the above embodiment, the rotating body to which one end of the link 100 is pivotally attached is the gear 7, and it also serves as a transmission mechanism for transmitting the rotation of the servo motor 4. However, the output of the servo motor is changed to another transmission mechanism. Alternatively, for example, a timing belt and a timing gear may be transmitted to rotate a rotating body to which one end of the link 10 is pivotally attached.

As described above, according to the present invention, the rotating body is rotated by the servo motor, and the ejector plate is moved and the ejector pin is projected and retracted by the links having both ends pivotally mounted between the rotating body and the ejector plate. Therefore, the ejector pin can be made to project once by one rotation of the rotating body, and if the rotating body is rotated a plurality of times, the ejector pin can be made to project by the number of times of rotation and the product can be projected. The servo motor needs to be accelerated and decelerated once each at the start and at the end of ejection. Compared to the conventional product ejection device driven by the servo motor, the number of accelerations and decelerations is increased when multiple ejection operations are performed. The energy loss of the servo motor is reduced due to the small number.

[Brief description of drawings]

FIG. 1 is a plan view of an essential part of an embodiment of the present invention, and FIG. 2 is a sectional view of an essential part of a conventional servomotor-driven product ejector. 1,20 …… Movable platen, 2,27 …… Ejector plate,
3,28 …… Ejector pin, 4,21 …… Servo motor, 6…
… Gear, 7 …… Gear as a rotating body, 10 …… Link, 9,
11 ... Pin.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-58-167143 (JP, A) JP-A 61-10423 (JP, A) JP-A 51-561 (JP, A) JP-A 62- 248615 (JP, A)

Claims (1)

[Claims] 1. In a product ejecting mechanism of an injection molding machine for ejecting a product from a mold, a rotating body driven by a servomotor, and an ejector in which one end of the rotating body is pivotally attached to one end and an ejector pin is fixed to the other end. A product ejecting device for an injection molding machine, which is provided with a link pivotally attached to a plate, and in which a ejector pin is projected and retracted in a mold by driving a servo motor.