JPH0430894B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a nozzle touch mechanism for moving an injection unit to bring a nozzle into contact with a mold in an injection molding machine.

Prior Art A nozzle touch mechanism in a conventional injection molding machine uses a hydraulic cylinder to move the injection unit using oil pressure, and uses the oil pressure to press the nozzle against the mold at a constant pressure. A nozzle touch mechanism has also been developed in which a motor is used to move a ball screw in the axial direction without using hydraulic pressure, and the nozzle is brought into contact with and pressed against a mold.

Problems to be Solved by the Invention An object of the present invention is to provide an inexpensive nozzle touch mechanism in which the nozzle touch mechanism is driven by a motor and does not use a ball screw.

Means for Solving the Problems An extruder base is provided slidably on the base of an injection molding machine, an injection unit is fixed to the extruder base, and a first motor driven by a motor is attached to the extruder base. sprocket is rotatably fixed, a second sprocket is also rotatably fixed, one end of a chain is fixed to the front of the base of the injection molding machine, that is, to the mold side, and the chain is fixed to the first sprocket. The first sprocket of the chain is engaged with a second sprocket, and then fixed to a traction device for eliminating slack in the chain fixed to the rear of the base of the injection molding machine, and the first sprocket of the chain is engaged with the second sprocket. The above-mentioned problem is solved by fixing to the base of the injection molding machine a tension device which is fixed to the front of the base of the injection molding machine and which pulls the chain laterally with respect to the running direction of the chain.

Operation When the extruder base is in the retracted position and the nozzle is removed from the mold, the chain is pulled laterally by the tension device and maintained in a bent state. When the motor is driven to drive the first sprocket and cause the chain to run, the tensile force exerted by the tension device is strong.
The extruder base slides on the base of the injection molding machine, and the nozzle comes into contact with the mold. When the nozzle comes into contact with the mold and the extruder base stops moving forward, the chain is pulled laterally by the tensioning device so that it becomes straight, against the force of the tensioning device. A motor rotates the first sprocket. As a result, the force applied by the tension device is transmitted to the nozzle, and the nozzle presses the mold with this force.
Then, when the appropriate force is applied by the tension device, the drive of the motor is stopped and the movement of the chain and the first sprocket is locked, and the nozzle presses against the mold with an appropriate set pressure. That will happen.

The traction device absorbs slack in the chain between the first and second sprockets and the traction device, which occurs when the chain is moved by the first sprocket after the nozzle contacts the mold. It is.

Embodiment FIG. 1 is a side view of an embodiment of the present invention, in which 1 is an injection unit, 2 is a heating cylinder, 3 is a nozzle, and 4 is a side view of an embodiment of the present invention.
1 is a mold, and 5 is an extruder base to which the injection unit 1 is fixed, which is placed on a base 6 of an injection molding machine so as to be able to slide from side to side in FIG. S1 to S7 are sprockets, and the sprockets S1 to S7 correspond to chains C1 to C as described later.
3 is installed. M is a motor with a brake.

FIG. 2 is a plan view of the extruder base 5 when the injection unit 1 is removed from the extruder base 5. The extruder base 5 is placed on the rails L1 and L2 on the base 6, and the extruder base 5 is placed on the left and right sides in FIG. The top surface of the extruder base 5 becomes flat as shown in the partially sectional side view of the extruder base 5 shown in FIG. 3, so that the injection unit 1 can be placed thereon. It's summery. Sprockets S1 to S5 are provided on the lower surface of the extruder base 5. Also,
A motor M with a break is fixed to one end of the upper surface of the extruder base 5, and a sprocket S1 is fixed to the motor shaft of the motor M, and is rotatably fixed to the sprocket S1 and the extruder base 5. A first chain C1 is mounted between the large sprockets S2. In addition,
As shown in FIG. 2, the first chain C1 includes:
Sprocket S for tension adjustment of the first chain
5 are engaged. In addition, the above sprocket S2
A sprocket S3 smaller than the sprocket S2 is fixed to the shaft of the sprocket.
2, S3 are adapted to rotate integrally.
A second chain C2 is connected to the sprocket S4 rotatably fixed to the extruder base 5 and the sprocket S3, and one tip of the second chain C2 is attached to the base as shown in FIG. It is fixed to a traction device 9 fixed to 6. This traction device 9 uses a spring 10 to pull the second chain C2. The other end of the second chain C2 is connected to a sprocket S6 rotatably fixed to the base 6.
(See FIGS. 1 and 4) and then fixed to the base 6. In addition, in Figures 2 and 3,
Reference numeral 8 denotes a hole into which a drive pin for connecting the extruder base 5 and the injection unit 1 and for moving the injection unit 1 is fitted. Further, the sprocket S5 can be slid and fixed in a groove 11 provided in the extruder base 5, and the tension of the first chain can be adjusted by changing the position of the sprocket S5.

FIG. 4 is a diagram showing the relationship between the sprockets S1 to S6 and another sprocket S7. As mentioned above, the sprockets S1 to S5 are fixed to the extruder base 5, but the sprockets S6 and S7 are fixed to the extruder base 5. It is rotatably fixed to the base 6, and a third chain C3 is attached to the sprocket S7, one end of the third chain C3 is fixed to the second chain C2, and the other end is attached to a tensioning device. It is fixed to 13.
The tensioning device 13 tensions the third chain by means of a spring 14, so that the second chain fixed to the tip of the third chain is tensioned as shown in FIG. . Note that 15 is a fixing device for fixing the second chain C2 to the base 6, and LS is a limit switch.

Next, the operation of this embodiment will be explained. When the motor M is driven and rotates the sprocket S1 in the counterclockwise direction in FIGS. 2 and 3, the first chain C1 also rotates the sprocket S2 in the counterclockwise direction, and the sprocket fixed coaxially with the sprocket S2 is rotated by the first chain C1. S3 also rotates, pulling the second chain C2 to the right in FIGS. 2 and 3. However, since the second chain C2 is fixed to the base 6 with the fixing device 15, instead of the second chain C2 being pulled, the extruder base 5 itself is pulled along the rails L1 and L2 as shown in FIG. It will move to the left. At this time, since the diameters of sprocket S2 and sprocket S3 are different and the diameter of sprocket S2 is larger, the force of motor M is amplified by these sprockets S2 and S3 and is transferred to the second sprocket.
It will be added to Chain C. In this way, the extruder base 5 moves and the injection unit 1
moves together, and when the nozzle 3 comes into contact with the mold 4,
Movement of the extruder base 5 (Figs. 1 and 2)
(to the left in the figure) stops. Then, when the motor M is driven further, the second chain C2 is pulled and moved, and the second chain C2 between the sprocket S3 and the traction device 9 becomes slack, but this slack is absorbed by the traction device. It is absorbed by the contraction of spring 10 of 9. On the other hand, the second chain C2 between the sprocket S6 on the other end side of the second chain C2 and the fixing member 15 shifts from the bent state shown by the solid line in FIG. 4 to the straight state shown by the broken line in FIG. do. At that time, the third chain C3 moves while pulling the spring 14 of the tension device 13, and when the second chain C2 reaches the state shown by the broken line in FIG. 4, the limit switch LS is activated.
Since it is turned on, the brake of the motor M is actuated and the drive of the motor M is stopped. The force generated by the amount of elongation of the spring 14 of the tension device 13 at this time, that is, the amount of elongation of the spring 14 when the second chain C2 moves from the solid line position to the broken line position in FIG. It becomes a pressure contact force. For example, if the force required to press the nozzle 3 against the mold 4 is 300 kg, the amount by which the spring 14 expands in the third chain C3 while the second chain C2 moves from the solid line in FIG. It is sufficient to use a spring with a spring coefficient such that a repulsive force of 300 kg is generated when the spring 14 is turned.

Furthermore, when removing the nozzle 3 from the mold 4, the motor M is rotated in the opposite direction and the sprockets S2 and S are rotated in the opposite direction.
3 in the clockwise direction, the extruder base 5 moves rightward in FIGS. 1 and 2, and the nozzle 3 is separated from the mold.

In the above embodiment, the sprocket S7 and the third chain C3 are provided, and the second chain C2
Although the sprocket S7 and the third chain C3 are not provided, the second chain C2 may be directly pulled by the tension device 13.

Furthermore, although the motor M with a brake was used in the above embodiment, a normal motor was used instead of a motor with a brake, and when the limit switch LS was turned on, the rotation of the sprockets S3 and S2, that is, the rotation of the sprockets S3, A locking device that stops the rotation of the S4 shaft is attached to the shaft or sprocket S4.
3. It may be provided in S4. In addition, the limit switch LS is configured to detect when the second chain C2 is in the state shown by the broken line in FIG. 4, but the tension device 1
The amount of elongation of the spring 14 in No. 3 may be detected. That is, when the nozzle 3 is elongated to the extent that it generates an appropriate force (for example, 300 kg) to press against the mold 4, the limit switch LS detects the movement of the member 16 that moves due to the expansion and contraction of the spring 14 and is turned ON. Good too. Note that the second chain C2
does not necessarily have to be fully extended as shown by the broken line in FIG. 4; it is only necessary that the tensioning device elongates by an appropriate amount and generates an appropriate force. Therefore, the pressure force of the nozzle against the mold can be varied and adjusted by adjusting the setting position of the limit switch.

Effects of the Invention The present invention uses a tension device consisting of a sprocket, a chain, and a spring to touch a nozzle using a motor, and adjusts and applies the pressing force of the nozzle to the mold using the tension device.
It has a simple structure, compared to the conventional ball screw that uses a motor to touch the nozzle.
An inexpensive nozzle touch mechanism can be obtained.

[Brief explanation of drawings]

Fig. 1 is a side view of one embodiment of the present invention, Fig. 2 is a plan view of the extruder base of the same embodiment with the injection unit removed, and Fig. 3 is a partially cutaway side view of the extruder base. 4 are diagrams for explaining the structure and operation of the sprocket and chain of this embodiment. DESCRIPTION OF SYMBOLS 1...Injection unit, 3...Nozzle, 4...Mold, 5...Extruder base, 6...Base of injection molding machine, M...Motor, C1-C3...Chain, S1-S7... Sprocket, 13...
Tension device, 9... Traction device.

Claims (1)

[Scope of Claims] 1. In a nozzle touch mechanism that fixes an injection unit and presses a nozzle against a mold by advancing an extruder base that is slidably placed on the base of an injection molding machine, the extruder base rotates. a first sprocket rotatably fixed to the extruder base and driven by a motor; a second sprocket rotatably fixed to the extruder base; and the first sprocket having one end fixed to the front of the base of the injection molding machine.
Then, after meshing with the second sprocket, a chain whose other end is fixed to a traction device fixed to the rear of the base of the injection molding machine, and a chain fixed to the front of the base of the injection molding machine. A nozzle touch mechanism comprising a tensioning device fixed to the base of the injection molding machine for pulling the chain between the fixed end and the first sprocket laterally with respect to the running direction of the chain. 2. The nozzle touch mechanism according to claim 1, wherein the tension device is attached to the other end of the second chain, which is fixed to one end of the chain and guided by a third sprocket. 3. The nozzle touch mechanism according to claim 1 or 2, wherein the motor is a motor with a brake. 4. The tension device is composed of a spring, and the spring coefficient of the spring is set so that the force generated by a certain amount of expansion and contraction of the spring becomes a set pressure at which the nozzle comes into pressure contact with the mold. Claims 1 and 2 of the above claims are characterized by:
Nozzle touch mechanism according to item 1 or 3.