JP2001170980A - Injection molding machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To facilitate the maintenance of an injection molding machine, to improve the efficiency of the machine, and to decrease the depth of the machine. SOLUTION: The injection molding machine has a stator core, a rotor core which is arranged freely rotatably, a hollow output shaft which outputs rotation generated in the rotor core, a ball screw shaft 25 which is connected to the output shaft and converts rotational movement by the rotation of the output shaft into linear movement and a ball screw nut 59, and a member which receives the linear movement and is moved forward/backward without applying an eccentric load to the ball screw shaft 25 and the ball screw nut 59. The rotational movement generated in the rotor core is converted into the linear movement by the screw shaft 25 and the nut 59, and the member is moved forward/backward without applying the eccentric load to the screw shaft 25 and the nut 59. Since the eccentric load is not applied to the screw shaft 25 and the nut 59, the efficiency of the machine can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to an injection molding machine.

[0002]

2. Description of the Related Art Conventionally, in an injection molding machine, a resin heated and melted in a heating cylinder is injected at a high pressure, filled in a mold cavity, and cooled in the cavity. After solidification, the mold is opened and the molded product is taken out.

The injection molding machine has a mold clamping device and an injection device, and the mold clamping device includes a fixed platen and a movable platen, and a mold clamping cylinder moves the movable platen forward and backward to move the mold toward and away from the mold. It has become.

On the other hand, the injection device has a heating cylinder for heating and melting the resin supplied from the hopper, and an injection nozzle for injecting the melted resin, and a screw is provided in the heating cylinder so as to be able to move forward and backward. Is done. Then, the resin can be injected by advancing the screw, and weighing can be performed by rotating the screw.

An injection molding machine using a servomotor for moving the movable platen forward and backward has been provided.

FIG. 2 is a front view of a conventional mold clamping device, and FIG. 3 is a side view of the conventional mold clamping device. Note that the upper side of the center line in FIG. 2 indicates the mold closed state of the mold clamping device, and the lower side of the center line indicates the mold open state of the mold clamping unit.

In FIG. 1, reference numeral 11 denotes a movable platen to which a movable mold (not shown) is attached, and 12 denotes a toggle support. The toggle support 12 and a fixed platen (not shown) are connected by a tie bar 13, and the tie bar 1
The movable platen 11 is slid along (3) to close, close and open the mold. For this purpose, the toggle support 12 and the movable platen 11
And a toggle mechanism 15 is disposed between the
The movable platen 11 is moved forward and backward (moves in the left-right direction in FIG. 2) by being driven by the servo motor 16 for mold clamping drive.

The toggle mechanism 15 includes a toggle lever 1 supported swingably with respect to the toggle support 12.
8, the toggle lever 18 and the movable platen 11 are connected to each other, and the arm 19 and the crosshead 21 that are swingably supported with respect to the toggle lever 18 and the movable platen 11, and the toggle lever 18 and the crosshead 21 are connected to each other. It is composed of a toggle lever 22 that is connected and swingably supported with respect to the toggle lever 18 and the crosshead 21.

At the center of the toggle support 12, a ball screw shaft 25 is rotatably supported in the direction of the arrow by a bearing 24, and the ball screw shaft 25 and a nut formed on the crosshead 21 are screwed. Be combined.
Then, by rotating the ball screw shaft 25, the crosshead 21 is moved forward and backward in the direction of the arrow.
In the state shown below the center line in FIG. 2, the mold open state of the mold clamping device is formed, and at the forward end position of the crosshead 21, the toggle mechanism 15 is brought into the state shown above the center line in FIG. The closed state of the clamping device can be formed.

A belt transmission mechanism 26 is disposed between the servo motor 16 and the ball screw shaft 25.
The belt transmission mechanism 26 includes a pulley 27 disposed on the output shaft of the servomotor 16, a pulley 28 disposed on the tip of the ball screw shaft 25, and a timing belt stretched between the pulleys 27 and 28. 29.

Therefore, when the servo motor 16 is driven, the rotation of the servo motor 16 is transmitted to the ball screw shaft 25 via the belt transmission mechanism 26. Then, the rotary motion is converted into a linear motion by the ball screw shaft 25 and the nut, the toggle mechanism 15 is operated, and the mold is closed, clamped and opened. An ejector mechanism 31 for ejecting an ejector pin (not shown) is provided on the toggle mechanism 15 side of the movable platen 11 when the mold is released after the mold is opened.

FIG. 4 is a view showing an ejector device mounting portion of another conventional mold clamping device.

In the figure, reference numeral 32 denotes a servo motor for an ejector, 33 and 34 denote ball screw shafts for an ejector, 3
5 to 37 are pulleys, 38 is a timing belt stretched between the pulleys 35 to 37, 39 is an ejector plate,
41 is a guide bar.

In this case, the ball screw shafts 33 and 34 are divided into two shafts, and are arranged with a center portion therebetween.
When the mold is opened, the ball screw shaft 25 for mold clamping (FIG. 2) does not interfere with the ball screw shafts 33 and 34 for ejectors. In the drawing, reference numeral 11 denotes a movable platen, 1
3 is a tie bar.

FIG. 5 is a front view of still another conventional mold clamping device. Note that the upper side of the center line in FIG. 5 indicates the mold closed state of the mold clamping device, and the lower side of the center line indicates the mold open state of the mold clamping device.

In FIG. 1, reference numeral 11 denotes a movable platen to which a movable mold (not shown) is attached, and 12 denotes a toggle support. The toggle support 12 and a fixed platen (not shown) are connected by a tie bar 13, and the tie bar 1
The movable platen 11 is slid along 3 to close, close and open the mold. for that reason,
A toggle mechanism 15 is provided between the toggle support 12 and the movable platen 11, and the toggle mechanism 15 is operated by a servo motor 16 (FIG. 3) for mold clamping drive, whereby the movable platen 11 moves forward and backward. (Moved in the left-right direction in the figure).

The toggle mechanism 15 includes a toggle lever 1 swingably supported by the toggle support 12.
8, an arm 19 connected to the toggle lever 18 and the movable platen 11 so as to be swingable with respect to the toggle lever 18 and the movable platen 11, a crosshead 21 fixed to a ball screw shaft 25, and the toggle Lever 1
8 and the crosshead 21, and includes a toggle lever 18 and a toggle lever 22 supported swingably with respect to the crosshead 21.

At the center of the toggle support 12, a nut 40 is rotatably provided by a bearing 24.
The nut 40 and the ball screw shaft 25 are screwed together. Then, by rotating the ball screw shaft 25, the crosshead 21 is moved forward and backward,
1 at the retreat limit position, the toggle mechanism 15 is set to a state shown below the center line in the drawing to form the mold open state of the mold clamping device, and at the forward limit position of the crosshead 21,
The mold closing state of the mold clamping device can be formed by setting the toggle mechanism 15 to a state shown above the center line in the drawing.

A pulley 28 is provided on the nut 40, and the rotation of the servomotor 16 is transmitted to the ball screw shaft 25 via the pulley 28. Then, the rotational motion is converted into a linear motion by the ball screw shaft 25 and the nut 40, the toggle mechanism 15 is operated, and the mold is closed, clamped and opened.

In this case, since the ball screw shaft 25 is moved backward (moves to the left in the drawing) in the mold open state, the ball screw shaft 25 and the toggle mechanism 15 do not interfere with each other.

[0021]

However, in the conventional injection molding machine, the timing belts 29, 3
No. 8 has relatively low durability and wears while the mold clamping device is repeatedly operated, so that abrasion powder is generated and the surroundings are soiled. Therefore, maintenance and management of the injection molding machine becomes difficult.

Further, an eccentric load is applied to each of the pulleys 28, 35, 36 and 37 due to the tension of each of the timing belts 29 and 38, and the efficiency of the ball screw shaft 25 is reduced.

The timing belts 29 and 38 are
Since the durability is low, expansion occurs, and the control accuracy of the mold clamping device is reduced, or breakage occurs, and it is necessary to replace the mold clamping device in a relatively short time. Therefore, each timing belt 2
It is conceivable to increase the durability by changing the materials of the materials 9 and 38, but in that case, noise occurs during high-speed operation.

In the case of the mold clamping device shown in FIGS. 2 and 3, in the mold open state, the movable platen 11 retreats as the crosshead 21 retreats. Is left as it is, it is necessary to form a structure in which the ball screw shaft 25 does not interfere with the toggle lever 18, the arm 19, the toggle lever 22, and the like. Further, since the servo motor 16 protrudes from the side surface of the toggle support 12, the dimension in the depth direction of the mold clamping device also increases.

In the case of a two-axis type ejector device having two ball screw shafts 33 and 34 as shown in FIG. 4, interference between the ball screw shafts 33 and 34 and the toggle mechanism is prevented. However, not only does the number of parts increase, the cost of the mold clamping device increases,
Replacement of the timing belt 38 becomes difficult. Further, since the servo motor 32 protrudes from the side surface of the movable platen 11, the dimension in the depth direction of the mold clamping device also increases.

In the case of the mold clamping device shown in FIG. 5, since the ball screw shaft 25 is retracted and protrudes rearward in the mold open state, the axial dimension of the mold clamping device becomes large.

The present invention solves the problems of the conventional injection molding machine, facilitates maintenance and management, increases the efficiency of the ball screw shaft, and reduces the dimension in the depth direction. An object of the present invention is to provide an injection molding machine that can be made smaller.

[0028]

For this purpose, in an injection molding machine of the present invention, a stator core, a rotor core rotatably disposed on the inner peripheral side of the stator core, and
A hollow output shaft attached to the rotor core and outputting a rotation generated by the rotor core, a ball screw shaft and a ball screw nut connected to the output shaft and converting rotational motion due to rotation of the output shaft into linear motion; And a member that can be moved forward and backward without receiving an eccentric load on the ball screw shaft and the ball screw nut in response to the linear motion.

[0029]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a front view of a mold clamping device according to an embodiment of the present invention, FIG. 6 is a side view of the mold clamping device of the embodiment of the present invention, and FIG. 7 is a servomotor of the embodiment of the present invention. FIG. Note that the upper side of the center line in FIG. 1 shows the mold closed state of the mold clamping device, and the lower side of the center line in FIG. 1 shows the mold open state of the mold clamping device.

In the drawing, reference numeral 11 denotes a movable platen to which a movable mold (not shown) is attached, 12 denotes a toggle support, and the toggle support 12 and a fixed platen (not shown) are connected by a tie bar 13;
The movable platen 11 is slid along 3 to close, close and open the mold. for that reason,
A toggle mechanism 15 is disposed between the toggle support 12 and the movable platen 11, and the movable mechanism 11 is operated by the driving device 50, so that the movable platen 11 moves forward and backward (moves left and right in FIG. 1). Let me do.

The toggle mechanism 15 includes a toggle lever 1 that is swingably supported on the toggle support 12.
8, a cross head that connects the toggle lever 18 and the movable platen 11 and is swingably supported by the toggle lever 18 and the movable platen 11 and a ball screw shaft 25 via a nut 21a. 21 and a toggle lever 22 which connects the toggle lever 18 and the crosshead 21 and is swingably supported by the toggle lever 18 and the crosshead 21.

At the center of the toggle support 12, a driving device 50 is disposed so as to project rearward (to the left in FIGS. 1 and 7), and the driving device 50 is directly fixed to the toggle support 12 by bolts 51. Is done. The driving device 50 is rotatably supported by a driving device case 52, a servo motor 53 disposed in the driving device case 52, and the driving device case 52, and outputs the rotation of the servo motor 53. And a hollow rotary sleeve 54 as an output shaft.

The drive unit case 52 includes a side wall 52a disposed in contact with the toggle support 12, a side wall 52b disposed opposite to the side wall 52a, and a cylinder connecting the side walls 52a, 52b. Cover 52c.
Further, the servo motor 53 is connected to the drive device case 5.
2 and a rotor core 53b rotatably disposed on the inner peripheral side of the stator core 53a. Further, the rotating sleeve 54
Is composed of a large-diameter portion 54a and a small-diameter portion 54b formed rearward from the large-diameter portion 54a.
Is rotatably supported by the bearing 56 on the side wall 52a, and the small diameter portion 54b is rotatably supported by the bearing 57 on the side wall 52b.

A ball screw nut 59 is fixed to the inner periphery of the large diameter portion 54a by a bolt 60, and a rotor core 53b is fitted (fixed) to the outer periphery of the small diameter portion 54b and fixed. The ball screw shaft 2
5 extends rearward from the crosshead 21, penetrates the toggle support 12, and is screwed with the ball screw nut 59. Then, by driving the servo motor 53 and rotating the ball screw nut 59 in the direction of the arrow, the ball screw shaft 25 is moved forward and backward in the direction of the arrow. In the state shown below the center line in the above, the mold open state of the mold clamping device is formed, and at the forward limit position of the ball screw shaft 25, the toggle mechanism 15 is brought into the state shown above the center line in FIG. A closed state of the mold clamping device can be formed.

In this case, the ball screw shaft 25 advances and retreats in the small-diameter portion 54b, and the small-diameter portion 54
Since it is accommodated in b, there is no need to make the axial dimension of the mold clamping device too large.

Further, since the timing belt is not used, abrasion powder of the timing belt is not generated and the surroundings are not stained, so that maintenance and management of the injection molding machine can be facilitated. Further, since the servo motor does not overhang the side surface of the toggle support 12, the dimension in the depth direction of the mold clamping device can be reduced.

Since no eccentric load is applied to the ball screw shaft 25 and the ball screw nut 59, the efficiency of the ball screw shaft 25 and the mold clamping device can be increased.

In the mold open state, the ball screw shaft 2
5 is retracted, so that the ball screw shaft 25 and the toggle mechanism 15 do not interfere with each other. Therefore, the conventional hydraulic toggle mechanism can be replaced with an electric toggle mechanism as it is. Furthermore, in the mold open state, the ball screw shaft 25 is retracted, so that the ejector device (not shown) does not interfere with the toggle mechanism 15. Therefore, the ejector device does not need to be a two-axis type using a timing belt, so that the number of parts is reduced and the cost of the injection molding machine can be reduced.

As described above, when the servomotor 53 is driven to rotate the ball screw nut 59, the rotational motion is converted into a linear motion by the ball screw nut 59 and the ball screw shaft 25, and the toggle mechanism 15 is operated. The mold is closed, closed and opened.

An encoder 61 is provided at the rear end (left end in FIG. 7) of the side wall 52b, and the small diameter portion 54b or the ball screw nut 59 is
Rotation can be directly detected.
Therefore, the detection accuracy of the rotation speed can be increased.

In this embodiment, any of an induction type and a synchronous type can be used as the servo motor 53.

It should be noted that the present invention is not limited to the above-described embodiment, but can be variously modified based on the gist of the present invention, and they are not excluded from the scope of the present invention.

[0044]

As described above in detail, according to the present invention, in an injection molding machine, a stator core, a rotor core rotatably disposed on the inner peripheral side of the stator core, and a rotor core mounted on the rotor core. A hollow output shaft that outputs the rotation generated by the rotor core, a ball screw shaft and a ball screw nut that are connected to the output shaft, and that convert the rotational motion due to the rotation of the output shaft into a linear motion, And a member that can move forward and backward without applying an eccentric load to the ball screw shaft and the ball screw nut.

In this case, the rotational motion generated in the rotor core is converted into a linear motion by the ball screw shaft and the ball screw nut, and the member moves forward and backward without applying an eccentric load to the ball screw shaft and the ball screw nut. Can be

Accordingly, since no eccentric load is applied to the ball screw shaft and the ball screw nut, the efficiency of the injection molding machine can be increased.

Further, since the timing belt is not used, abrasion powder of the timing belt is not generated and the surroundings are not stained, so that maintenance and management of the injection molding machine can be facilitated. Further, since the stator core and the rotor core do not protrude from the side surface of the injection molding machine, the dimension of the injection molding machine in the depth direction can be reduced.

[Brief description of the drawings]

FIG. 1 is a front view of a mold clamping device according to an embodiment of the present invention.

FIG. 2 is a front view of a conventional mold clamping device.

FIG. 3 is a side view of a conventional mold clamping device.

FIG. 4 is a view showing an ejector device mounting portion in another conventional mold clamping device.

FIG. 5 is a front view of still another conventional mold clamping device.

FIG. 6 is a side view of the mold clamping device according to the embodiment of the present invention.

FIG. 7 is a detailed view of a servomotor according to the embodiment of the present invention.

[Explanation of symbols]

 15 toggle mechanism 25 ball screw shaft 53a stator core 53b rotor core 54 rotating sleeve 59 ball screw nut

Claims (1)

[Claims] 1. A stator core, (b) a rotor core rotatably disposed on the inner peripheral side of the stator core, and (c) a rotor core attached to the rotor core to output rotation generated by the rotor core. A hollow output shaft,
(D) a ball screw shaft and a ball screw nut that are connected to the output shaft and convert a rotational motion due to rotation of the output shaft into a linear motion; and (e) receive the linear motion and receive the ball screw shaft and a ball screw nut. A member that can be advanced and retracted without applying an eccentric load to the injection molding machine.