JP2001088182A - Driving device for injection molding machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a driving device for an injection molding machine, in which the smoothness of actuation, stability of control for position and pressure, and controlling precision are enhanced and also such nonconformity is solved that the deterioration of a mechanism part is accelerated. SOLUTION: The driving device for the injection molding machine is equipped with a stress isolating mechanism 10 which has a regulation member 7 provided in a ball screw part 5 or a nut part 6 of a ball screw mechanism 4, a regulation mechanism 8 regulating the turning of the regulation member 7 and a combination member 9 which is combined freely turnably and displaceably for the regulation member 7.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a driving device for an injection molding machine for converting a rotary motion of a drive motor into a linear motion by a ball screw mechanism to drive a movable portion such as a movable plate forward and backward.

[0002]

2. Description of the Related Art Conventionally, a driving device for an injection molding machine that converts the rotational motion of a driving motor into a linear motion by a ball screw mechanism and drives the movable plate forward and backward is known from Japanese Patent No. 2521591.

In this type of drive device, a ball screw portion (or a nut portion) of a ball screw mechanism is rotatably mounted on a drive base, and the nut portion (or a ball screw portion) is connected to a movable platen. The drive motor mounted on the drive base and the ball screw section were connected by a rotation transmission mechanism. In this case, the movable plate is slidably mounted on the tie bar. Thus, when the drive motor is operated, the rotation of the drive motor is transmitted to the ball screw portion attached to the drive base via the rotation transmission mechanism, and is converted into linear motion by the ball screw mechanism, so that the movable platen moves straight. The nut is moved in the forward / backward direction (the mold opening / closing direction) by the moving nut portion.

[0004]

However, in the conventional driving device described above, the nut portion (ball screw portion) of the ball screw mechanism is directly fixed to the movable platen. In tightening, unnecessary stress (load) in the rotating direction (twist direction) is applied to the movable plate due to the sliding resistance and reaction force between the nut portion and the ball screw portion. As a result, the smoothness of operation is improved. There is a possibility that the stability of the control of the position and the pressure with respect to the position and the pressure and the control accuracy may be reduced, and there is a problem that the deterioration of the play in the mechanism is accelerated.

The present invention has been made to solve the problems existing in the prior art, and can improve the smoothness of operation, the stability of control with respect to position and pressure, and the accuracy of control. It is an object of the present invention to provide a drive device for an injection molding machine that can solve the problem of accelerated deterioration.

[0006]

According to the present invention, a rotary motion of a drive motor 3 is converted into a linear motion by a ball screw mechanism 4 to move a movable portion 2 such as a movable plate 2c of a mold clamping device Mc forward and backward. When configuring the driving device 1 of the injection molding machine M to be driven, a regulating member 7 provided on the ball screw portion 5 or the nut portion 6 of the ball screw mechanism 4 and a regulating mechanism 8 for regulating the rotation of the regulating member 7 And a coupling member 9 provided on the movable section 2 side and coupled to the regulating member 7 so as to be rotatable and displaceable. Thereby, the stress (load) in the rotation direction applied from the ball screw portion 5 or the nut portion 6 of the ball screw mechanism 4 is received by the regulating mechanism 8 via the regulating member 7 and is not transmitted to the movable section 2 side. .

In this case, according to a preferred embodiment, when the regulating mechanism 8 is constructed, the end 7se of the regulating member 7 is used.
, And guide rails 12 slidably loaded with the sliders 11, or the end portions 7 se of the regulating member 7 may be replaced with tie bars 13, which guide the movable portion 2. It may be slidably loaded. Further, it is desirable to interpose a friction reducing member 14 for reducing contact friction between the sliding contact surfaces in the stress dividing mechanism 10.

[0008]

Next, preferred embodiments according to the present invention will be described in detail with reference to the drawings.

First, the configuration of an injection molding machine M provided with a driving device 1 according to the present embodiment will be described with reference to FIGS.

In FIG. 1, M denotes an injection molding machine, which includes a mold clamping device Mc using the driving device 1 according to the present embodiment and an injection device Mi indicated by a virtual line. The mold clamping device Mc includes a fixed platen 20 and a drive base 21 which are spaced apart from each other.
1 is fixed on the machine base 22. In addition, four tie bars 13 are provided between the fixed platen 20 and the drive base 21 (see FIG. 2).
And the movable plate 2c is slidably mounted on the tie bars 13. The movable plate 2c has a movable type Cm.
At the same time, the fixed type Cc is mounted on the fixed platen 20. The movable mold Cm and the fixed mold Cc constitute a mold C. Further, a pair of left and right guide rails 12 is laid on the upper surface of the machine base 22 in parallel with the tie bars 13.
A slider unit 23 for supporting the lower surface of the movable platen 2c is slidably mounted on the guide rails 12, 12.

On the other hand, the driving device 1 according to the present embodiment is provided using the driving base 21. Reference numeral 4 denotes a ball screw mechanism, and the nut portion 6 of the ball screw mechanism 4 is rotatably attached to the drive stand 21. A drive motor (servo motor) 3 is disposed inside the machine base 22. And the drive motor 3
A toothed drive pulley 24 is mounted on the rotor shaft, and a toothed driven pulley 25 is coaxially mounted on the outer end surface of the nut portion 6.
A rotation transmission mechanism 27 is formed by extending a timing belt 26 between the five. In the center of the nut 6 is the ball screw 5
Are screwed together, and the end 5s of the ball screw portion 5 is coupled to the movable platen 2c side via a stress dividing mechanism 10 constituting a main part of the drive device 1 according to the present embodiment.

Next, a specific configuration of the stress dividing mechanism 10 will be described with reference to FIGS. 1 to 3. Reference numeral 7 denotes a regulating member having a constant thickness. 7s. As shown in FIG. 3, one end of the ball screw portion 5 is provided on one surface of the coupling portion 7c with a plurality of fixing screws 32.
And a circular housing recess 33 is provided on the other surface of the connecting portion 7c. Further, a pair of right and left sliders 11 and 11 are mounted on the bottom surface of the regulating portion 7s, which has a wide width on the lower side and an end portion 7se. The sliders 11, 11 constitute the regulating mechanism 8 by being slidably mounted on the guide rails 12, 12. In addition, guide rail 1
Linear guides (linear bearings) can be used for the sliders 2 and 12 and the sliders 11 and 11.

On the other hand, a connecting block 34 extending rearward is integrally provided on the rear surface of the movable board 2c. A disc-shaped sliding contact plate (bush) 35 made of a steel material or the like is fixed to the rear surface of the coupling block 34 with a plurality of fixing screws 36. The pin-shaped coupling member 9 is fixed with a plurality of fixing screws 37. In this case, the connecting member 9 is composed of a shaft portion 9m and a large-diameter flange portion 9f integrally formed at the tip of the shaft portion 9m.
In order to fix the shaft member, a sliding contact plate (bush) 38 and a friction reducing plate 39 are rotatably mounted on the shaft portion 9m. The friction reducing plate 39 constitutes the friction reducing member 14, and is formed in a ring shape from, for example, a brass material or the like. Further, the sliding contact plate 38 is formed in a ring shape using a steel material or the like. Thereby, the friction reducing plate 39
Is sandwiched between the sliding contact plate 35 and the sliding contact plate 38.
That is, the friction reducing plate 39 for reducing the contact friction is provided between the sliding contact surfaces.

When the joining member 9 is joined to the regulating member 7, the flange 9f of the joining member 9 is accommodated in the accommodation recess 33 of the regulating member 7, and the regulating member 7 is slid by a plurality of fixing screws 40. What is necessary is just to fix to the contact plate 38. As a result, the ball screw portion 5 and the coupling block 34 are coupled via the stress dividing mechanism 10, and the coupling block 34 becomes rotatable with respect to the regulating member 7. Also, the combining block 34
Therefore, even when a high pressure is applied from the ball screw portion 5 side, the contact friction between the sliding contact surfaces is reduced by the friction reducing plate 39, so that the coupling block 34 can smoothly rotate with respect to the regulating member 7. Is done.

Next, the operation of the driving device 1 according to the present embodiment will be described together with the operation of the mold clamping device Mc.

First, when the drive motor 3 operates, the rotation of the drive motor 3 is transmitted to the nut 6 via the rotation transmission mechanism 27. On the other hand, the end 5 s of the ball screw 5 is fixed to the regulating member 7, and the regulating member 7 is provided with the slider 11 provided on the end 7 s and the guide rail 12. Is rotated, the ball screw portion 5 moves in the straight traveling direction. Since the advance / retreat movement of the ball screw portion 5 is transmitted to the movable portion 2c via the stress dividing mechanism 10, the movable portion 2c moves forward / backward integrally with the ball screw portion 5, and the mold C is opened and closed and the mold is closed. Done.

In this case, especially in high-pressure mold clamping, the sliding resistance and the reaction force between the nut 6 and the ball screw 5 cause the ball screw 5 to rotate in the rotational direction (twist direction) from the nut 6. Although a stress (load) is applied, the stress in the rotation direction is applied from the ball screw portion 5 to the regulating member 7. Since the rotation of the regulating member 7 is regulated by the regulating mechanism 8, the stress is received by the regulating member 7 and is not transmitted to the movable platen 2c side. That is, since the movable platen 2c is rotatably coupled to the regulating member 7 via the stress dividing mechanism 10, unnecessary stress in the rotation direction is not transmitted to the movable platen 2c side, The smoothness of the operation of the tightening device Mc, the stability and control accuracy of the control for the position and pressure of the movable platen 2c (movable die Cm) are improved, and the problem of accelerated deterioration of the mechanism is also eliminated.

FIGS. 4 to 7 show modified examples of each part. FIG. 4 shows a modification of the regulation mechanism 8. In the embodiment shown in FIG. 2, the guide rails 12 are used, but the modified example shown in FIG. 4 uses the tie bars 13 loaded with the movable plate 2c. Guide holes were provided at both ends 7se, 7se, and slidably mounted on a pair of tie bars 13 located diagonally.

On the other hand, FIGS. 5 to 7 show modifications of the friction reducing member 14. The modified example shown in FIG. 5 uses a thrust bearing 42 instead of the friction reducing plate 39 of the embodiment shown in FIG.
1 was accommodated in the stepped recess. In the modified example shown in FIG. 6, the sliding contact surfaces of the sliding contact plate 43 and the sliding contact plate 44 are formed as spherical surfaces, so that misalignment can be corrected. In this case, one of the sliding contact plate 43 and the sliding contact plate 44 is
9, and can have a function as the friction reducing member 14. Further, the modification shown in FIG. 7 is obtained by changing the shapes of the sliding contact plate 38 and the friction reduction plate 39 of the embodiment shown in FIG. 3, and the modification is a modification of the friction reduction plate 39 formed in a ring shape. Instead, a friction reduction plate 46 integrally formed with a cylindrical portion that covers the outer peripheral surface of the shaft portion 9m is used, and the cylindrical portion is inserted through the sliding contact plate 45. In this case, the sliding contact plate 45 and the friction reducing plate 46 may be integrally formed of one material. Further, the coupling member 9 can be formed by providing a spherical portion 9s as shown by a virtual line in FIG.

Although the embodiments (modifications) have been described in detail above, the present invention is not limited to such embodiments (modifications), and the detailed configuration, shape, material, quantity,
In a method or the like, it can be arbitrarily changed, added, or deleted without departing from the gist of the present invention. For example, although the movable platen 2c of the mold clamping device Mc is illustrated as the movable portion 2, any movable portion such as a screw provided in the injection device Mi can be applied. The friction reducing member 14 is a concept including a surface treatment, a surface application treatment (coating treatment), and the like. The ball screw mechanism includes a so-called roller screw mechanism.

[0021]

As described above, the driving device for an injection molding machine according to the present invention comprises a regulating member provided on a ball screw portion or a nut portion of a ball screw mechanism, and a regulating mechanism for regulating the rotation of the regulating member. , Provided with a coupling member provided on the movable portion side and coupled to the regulating member so as to be rotatable and displaceable, the following remarkable effects can be obtained.

Since unnecessary stress in the rotating direction is not transmitted to the movable part, it is possible to improve the smoothness of operation, the stability and control accuracy of the control with respect to the position and the pressure, and to accelerate the deterioration of the mechanism. Can be resolved.

According to a preferred embodiment, if a friction reducing member for reducing contact friction is interposed between the sliding contact surfaces in the stress dividing mechanism, even if a high pressure is applied, the friction reducing member makes contact between the sliding contact surfaces. Since the friction is reduced, smooth rotation of the movable portion with respect to the ball screw mechanism is allowed.

[Brief description of the drawings]

FIG. 1 is a side view of a mold clamping device (injection molding machine) using a driving device according to a preferred embodiment of the present invention;

FIG. 2 is a rear view clearly showing a regulating member and a regulating mechanism in the driving device.

FIG. 3 is a partial cross-sectional side view of a stress dividing mechanism in the driving device.

FIG. 4 is a rear view showing a modified example of the regulating mechanism in the driving device.

FIG. 5 is a partial cross-sectional side view showing a modified example of the friction reducing member in the drive device.

FIG. 6 is a partial cross-sectional side view showing another modification of the friction reducing member in the drive device.

FIG. 7 is a partial cross-sectional side view showing another modification of the friction reducing member in the drive device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Driving device 2 Movable part 2c Movable board 3 Drive motor 4 Ball screw mechanism 5 Ball screw part 6 Nut part 7 Restriction member 7se End of restriction member 8 Restriction mechanism 9 Coupling member 10 Stress division mechanism 11 Slider 12 Guide rail 13 ... Tie bar 14 Friction reducing member M Injection molding machine Mc Mold clamping device

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Kenji Fujiki 2110 Nanjo Nanjo, Hanagi-gun, Hanishina-gun, Nagano F-term in Nissei Jushi Kogyo Co., Ltd. (reference) 4F202 CA11 CB01 CL01 CL22 CL39

Claims (5)

[Claims] In a driving device of an injection molding machine for converting a rotational motion of a drive motor into a linear motion by a ball screw mechanism to drive a movable portion forward and backward, a regulation provided on a ball screw portion or a nut portion of the ball screw mechanism. A regulating mechanism that regulates rotation of the regulating member, and a stress dividing mechanism that is provided on the movable portion side and that is coupled to the regulating member so as to be rotatable and displaceable. The driving device of the injection molding machine. 2. The drive device for an injection molding machine according to claim 1, wherein the movable portion is a movable plate of a mold clamping device. 3. The drive of an injection molding machine according to claim 1, wherein said regulating mechanism comprises a slider provided at an end of said regulating member, and a guide rail for slidably loading said slider. apparatus. 4. The driving device for an injection molding machine according to claim 1, wherein the regulating mechanism is configured such that an end of the regulating member is slidably mounted on a tie bar that guides the movable portion. 5. A driving device for an injection molding machine according to claim 1, wherein a friction reducing member for reducing contact friction is interposed between the sliding contact surfaces in said stress dividing mechanism.