ROTARY SHAFT TYPE TURNTABLE POSITIONING DEVICE OF INJECTION MOLDING MACHINE

Abstract

A rotary-shaft type turntable positioning device of an injection molding machine includes a first encoder and a second encoder installed at a servomotor of a positioning device and a speed reducer respectively, so that after the injection molding machine finishes an injection molding, the servomotor is used to drive the driving shaft and link the output shaft to drive the driving wheel to rotate a rotary shaft, while rotating and positioning a turntable. During rotation, signals of the first encoder and the second encoder are sensed to adjust the position, so as to control the turntable to be rotated to a precise position.

Claims

1. A rotary-shaft type turntable positioning device of an injection molding machine, and the positioning device being installed at a movable mold base, and the movable mold base including a rotary shaft sleeve with a driven wheel installed therein, and the positioning device comprising: a rotary shaft, installed in the rotary shaft sleeve, and having a turntable installed at an end of the rotary shaft; a displacement driving mechanism, installed an end of the rotary shaft without the turntable, and provided for driving the rotary shaft to move horizontally; a servomotor, having a first encoder and a driving shaft, wherein the servomotor is capable of rotating the driving shaft according to a received signal, and the first encoder is capable of sending a rotation signal of the driving shaft and transmitting the sensed signal to a central control unit; a speed reducer, installed at the servomotor and having a reduction gear driven by the driving shaft, and the reduction gear having an output shaft, and the output shaft having a second encoder and a driving wheel, and the second encoder being provided for sensing the rotation signal of the output shaft and transmitting the sensed signal to the central control unit; a central control unit, for transmitting a signal to the servomotor and receiving a signal from the first encoder and second encoder according to a default value; and a transmission belt, looped over the driving wheel and the driven wheel, and driven by the servomotor to drive the driving shaft to link the output shaft and drive the driving wheel to rotate the rotary shaft.

2. The rotary-shaft type turntable positioning device of an injection molding machine, as recited in claim 1, wherein, the first encoder and the second encoder are rotary encoders.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0010] FIG. 1 is a block diagram of an injection molding machine of the present invention;

[0011] FIG. 2 is a front view of an injection molding machine of the present invention;

[0012] FIG. 3 is a schematic view of a rotary shaft of an injection molding machine of the present invention, wherein the rotary shaft is pushed forward; and

[0013] FIG. 4 is a schematic view of a rotary shaft of an injection molding machine of the present invention, wherein the rotary shaft is retracted.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] The aforementioned and other objectives and advantages of the present invention will become clearer in light of the following detailed description of an illustrative embodiment of this invention described in connection with the drawings. It is intended that the embodiments and drawings disclosed herein are to be considered illustrative rather than restrictive.

[0015] With reference to FIGS. 1 to 3 for an injection molding machine rotary shaft turntable positioning device of the present invention, the injection molding machine rotary shaft turntable positioning device 1 is installed at a movable mold base 2, and the movable mold base 2 includes a rotary shaft sleeve 3 installed therein, and the rotary shaft sleeve 3 has a driven wheel 31, and the positioning device 1 comprises a rotary shaft 11, a displacement driving mechanism 13, a servomotor 14, a speed reducer 15, a central control unit 10 and a transmission belt 16. The rotary shaft 11 is installed in the rotary shaft sleeve 3, and a turntable 12 is installed at an end of the rotary shaft 11. The displacement driving mechanism 13 is installed at an end of the rotary shaft 11 without the turntable 12 and provided for driving the rotary shaft 11 to move horizontally. The servomotor 14 has a first encoder 141 and a driving shaft 142, and the servomotor 14 rotates the driving shaft 142 according to the received signal. The first encoder 141 is provided for sensing a rotation signal of the driving shaft 142. The speed reducer 15 is installed at the servomotor 14 and has a reduction gear 150 driven by the driving shaft 142, and the reduction gear 150 has an output shaft 151, and the output shaft 151 has a second encoder 152 and a driving wheel 153. The central control unit 10 transmits a signal to the servomotor 14 according to a default value and receives the sensed signal fed back from the first encoder 141 and the second encoder 152. The transmission belt 16 is looped over the driving wheel 153 and the driven wheel 31 of the rotary shaft sleeve 3.

[0016] In FIGS. 1 and 3, when the injection molding machine adopts a rotary-shaft type turntable, the male mold is mounted onto the turntable 12, and the displacement driving mechanism 13 is operated to push the turntable 12 until the male mold is closely engaged with the female mold (as indicated by the arrow in the figure). After the male and female molds are engaged, a first injection molding takes place. After the injection molding is completed, the displacement driving mechanism 13 is operated again to pull the turntable 12 back to its original position as shown in FIG. 4, so that the male mold is separated from the female mold, and then the speed and position (number of rounds) set by the central control unit 10 are received, and a pulse signal generated by the speed and position feedback is converted into a position signal to generate an appropriate voltage command in order to rotate the driving shaft 142 of the servomotor 14, and the servomotor 14 is driven while the first encoder 141 senses a rotation signal of the servomotor 14. After the central control unit 10 receives the signal of the first encoder 141, the rotation speed of the servomotor 14 is adjusted, and the driving shaft 142 drives the output shaft 151 of the reduction gear 150 of the speed reducer 15 to rotate while the second encoder 152 senses a rotation signal of the output shaft 151. If the central control unit 10 receives the signal of the second encoder 152 and the set position signal and the reduction gear 150 has an error due to the backlash, the central control unit 10 will re-adjust the command to the servomotor 14, so that the driving shaft 142 is rotated to drive the output shaft 151 of the speed reducer 15 to rotate. If the central control unit 10 receives a signal of the second encoder 152 which is in compliance with the set position signal, the output shaft 151 will drive the driving wheel 153 to rotate while the transmission belt 16 drives the rotary shaft 11, so that the turntable 12 fixed to the rotary shaft 11 can be rotated to a predetermined position, and then the displacement driving mechanism 13 pulls the rotary shaft 11 back again, and the male and female molds are engaged for the secondary injection.

[0017] By the first encoder 141 and the second encoder 152 installed at the servomotor 14 and the speed reducer 15 respectively, the signal transmitted from the first encoder 141 and the second encoder 152 to the central control unit 10 may be used to confirm whether or not there is an error occurred when the servomotor 14 drives the driving shaft 142 and the speed reducer 15. After the error is corrected, a command is transmitted to the servomotor 14 to control the rotation of the driving shaft 142, the speed reducer 15 and the driving wheel 153, so as to position the rotary shaft 11 precisely.