JP2003326432A - Electric clamp device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent excessive biting or chipping of tooth in a meshing part of a worm wheel and a worm by absorbing impact force when a work is clamped by a clamp lever. <P>SOLUTION: The worm 12 is connected to a driving shaft 25a of a motor 25, and the clamp lever 32 is provided on a worm wheel 30 meshed with the worm 12. The worm 12 is provided so that it can slide along an axial direction of the driving shaft 25a of the motor 25. A compression coil spring 17 is provided for absorbing impact force caused in a meshing part of the worm 12 and the worm wheel 30 when the clamp lever clamps the work. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric clamp device for rotating a clamp lever by the driving force of a motor.

[0002]

2. Description of the Related Art Conventionally, in this type of electric clamp device,
A worm gear device is interposed between the motor and the clamp lever. The worm gear device is composed of a worm and a worm wheel that mesh with each other,
The worm is connected to the drive shaft of the motor, while the worm wheel rotates together with the clamp lever. When the motor rotates, its driving force is transmitted to the clamp lever via the worm gear device.

[0003]

However, in the conventional electric clamp device, when the work is clamped, the rotation of the clamp lever is suddenly stopped, and at the same time, the rotation of the worm wheel is also suddenly stopped. At this time, the motor is stopped, but since it has inertial energy, it tries to continue rotating. Therefore, a large impact force is applied to the meshing portion between the worm wheel and the worm, and the tooth tips of these may excessively bite into the tooth roots of the mating teeth or may lack teeth.

The present invention has been made by paying attention to the problems existing in such conventional techniques. Its purpose is
An object of the present invention is to provide an electric clamp device capable of preventing excessive bite or missing teeth at a meshing portion of a worm wheel and a worm by absorbing impact force when a work is clamped by a clamp lever. .

[0005]

(Invention of Claim 1 ... Corresponding to Embodiments 1 to 3) In the invention of Claim 1, a worm is connected to a drive shaft of a motor, and the worm is meshed with the worm. In an electric clamp device in which a wheel is provided with a clamp lever that rotates integrally with the wheel and the driving force of the motor is transmitted to the clamp lever via a worm and a worm wheel, in the axial direction of the drive shaft of the motor. The gist is that the worm is slidable along and a buffer member is provided to absorb an impact force generated at the meshing portion of the worm and the worm wheel when the clamp lever clamps the work.

With this configuration, when the motor is driven,
The driving force is transmitted to the clamp lever via the worm and the worm wheel. Then, the workpiece is clamped or unclamped by rotating the clamp lever. When the clamp lever clamps the workpiece, the impact force generated at the meshing part between the worm and the worm wheel is absorbed by the compression coil spring. Preventing excessive biting,
It is possible to prevent missing teeth.

(Invention of Claim 2 ... Corresponding to Embodiments 1 to 3) In the invention of Claim 2, in the electric clamping device of Claim 1, the buffer member clamps the workpiece by the clamp lever. The point is to give elastic force in the direction.

With this structure, the elastic force of the compression coil spring always works in the direction of clamping the work. For this reason, even if the motor is de-energized during clamping, the clamping thrust is generated, so that the clamping force can be maintained.

(Invention of Claim 3 ... Corresponding to Embodiment 3) In the invention of Claim 3, in the electric clamp device according to Claim 1 or 2, the buffer member is an axial direction of the worm. The gist is that it is composed of a plurality of disc springs arranged in a.

With this structure, the installation space for the cushioning member can be reduced as compared with the case where a coil spring or the like is used as the cushioning member. As a result, it is possible to reduce the size of the electric clamp device.

(Invention of Claim 4 ... Corresponding to Embodiments 2 and 3) In the invention of Claim 4, in the electric clamp device according to any one of Claims 1 to 3, the motor is driven. The gist is that an Oldham coupling is provided between the shaft and the rotating shaft of the worm.

According to this structure, when the drive shaft of the motor and the rotary shaft of the worm are connected through the key, the key groove for assembling the key needs to be cut, but the Oldham coupling is used. If used, such cutting is unnecessary. Therefore, the manufacturing cost can be reduced.

(Invention of Claim 5 ... Corresponding to Embodiment 3) In the invention of Claim 5, in the electric clamp device according to any one of Claims 1 to 4, the worm wheel is a worm wheel. A gist is that a plurality of them are provided so as to face each other in the radial direction, and the respective clamp levers approach or separate as the worm wheels rotate.

According to this structure, when the worm rotates due to the driving of the motor, the respective clamp levers rotate in the directions toward and away from each other as the worm wheels rotate. In short, the workpieces are clamped when the clamp levers are close to each other, and the workpieces are unclamped when they are separated from each other.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION (First Embodiment) A first embodiment of the present invention will be described below with reference to the drawings.

As shown in FIGS. 1 (a), 1 (b) and FIG.
The electric clamp device 11 includes a tubular case 14 in which the worm 12 is housed, and openings at both ends thereof are closed by end caps 15 and 16, respectively. A compression coil spring 1 is provided on the inner end surface of the lower end cap 15.
7 is provided, and a movable bearing 19 is supported on the upper end portion thereof via a spring bearing 18. With such a configuration, the movable bearing 19 can move along the axial direction of the worm 12 while bending the compression coil spring 17.

A fixed bearing 20 is provided at the upper end opening of the case 14 at a predetermined distance from the movable bearing 19. The lower end of the worm 12 is inserted into the movable bearing 19 located below the case 14, and the upper end of the worm 12 is inserted into the stationary bearing 20 located above the case 14, whereby the worm 12 is rotatable. Has become. Moreover, since the worm 12 is supported by the movable bearing 19, the worm 12 is not supported by the movable bearing 19.
Along with that, it is movable along the vertical direction.

As shown in FIGS. 1 (a), (b) and FIG.
A motor 25 capable of rotating in the forward and reverse directions is fixed to the outer end surface of the lower end cap 15, and its drive shaft 25a has a through hole 1 formed in the central portion of the lower end cap 15.
It is inserted into the case 14 via 5a. Motor 2
The tip end of the drive shaft 25a of No. 5 is slidably inserted into an insertion hole 12b formed in the lower end of the rotary shaft 12a of the worm 12. The drive shaft 25a of the motor 25 and the rotary shaft 12a of the worm 12 are formed with key grooves 27a and 27b extending in the axial direction thereof, respectively. The rotational force of 25 is transmitted to the worm 12.

The key 26 has two key grooves 27a and 27b.
One of them is press-fitted and fixed, and the other is slidably engaged. As a result, the worm 12
While being guided by the key 26, it can slide along the axis of the drive shaft 25a of the motor 25. By the way, in this embodiment, the key 26 is the drive shaft 25a.
It is press-fitted and fixed in the key groove 27a formed in the.

As shown in FIGS. 1 (a), 1 (b) and FIG.
A housing 29 is attached to a side portion of the case 14, and a worm wheel 30 meshed with the worm 12 is housed inside the housing 29. Worm wheel 30
The rotary shaft 30a is rotatable by being inserted into a bearing 31 provided in the housing 29. Both ends of the rotary shaft 30a of the worm wheel 30 are projected from the housing 29, and a clamp lever 32 is connected to the projected portion via a key 33.

Then, as the worm wheel 30 rotates as the worm 12 rotates, the clamp lever 32 moves to the unclamp position P1 shown in FIG.
It is adapted to rotate with respect to the clamp position P2 shown in FIG. 1 (b). When the clamp lever 32 is located at the unclamp position P1, the work (not shown) is unclamped, and when it is located at the clamp position P2, the work is clamped.

In the electric clamp device 11 constructed as described above, when the motor 25 is rotated in a predetermined direction while the clamp lever 32 is arranged at the unclamp position P1, the clamp lever 32 is clamped. Position P
Rotate toward 2. When the clamp lever 32 reaches the clamp position P2, the power supply to the motor 25 is cut off, and the work (not shown) is clamped by the clamp lever 32.

When the work is clamped, the clamp lever 32 is suddenly stopped at the clamp position P2.
The worm wheel 30 also suddenly stops. Along with this, the power supply to the motor 25 is cut off.

Even if the power supply to the motor 25 is cut off, the motor 25 has inertial energy, so the worm 1
In 2, the rotational force acts in the same direction as the clamping direction. However, since rotation of the worm wheel 30 is restricted in the clamped state, the worm 12 starts to slide so as to approach the motor 25. Worm 12 slide,
That is, the linear motion causes the compression coil spring 17 to be compressed against its elastic force, and the inertial energy of the motor 25 is absorbed. Further, since the elastic force of the compressed compression coil spring 17 acts in the direction of increasing the clamping force of the clamp lever 32, the clamping thrust force can always be applied even when the power supply to the motor 25 is cut off.

Therefore, according to this embodiment, the following effects can be obtained. (1) When the clamp lever 32 clamps the workpiece, the compression coil spring 17 can absorb the impact force generated at the meshing portion between the worm 12 and the worm wheel 30. Therefore, at the meshing portion of the worm 12 and the worm wheel 30, it is possible to prevent each tooth tip from excessively meshing with the tooth root of the other. Therefore, when unclamping, the worm 12 and the worm wheel 30 can be smoothly rotated in a direction opposite to the direction in which they are clamped, and a smooth unclamping operation can be obtained.

(2) When the clamp lever 32 clamps the work, the impact force generated at the meshing portion between the worm 12 and the worm wheel 30 can be absorbed.
It is possible to prevent missing teeth.

(3) Worm 12 and worm wheel 3
The elastic force of the compression coil spring 17 that absorbs the impact force generated at the meshing portion with 0 always acts in the direction in which the clamp lever 32 clamps the work. Therefore, even when the motor 25 is de-energized during the clamping, the elastic force of the compression coil spring 17 can generate the clamping thrust, and the clamping force can be maintained.

(Second Embodiment) The second embodiment will be described focusing on the points different from the above-mentioned embodiment. The first
The same configurations as those of the embodiment will not be described and the same reference numerals will be given.

As shown in FIGS. 4 and 5, an Oldham coupling 40 is interposed between the rotary shaft 12a of the worm 12 and the drive shaft 25a of the motor 25. The Oldham coupling 40 is provided on the drive shaft 25 of the motor 25.
The drive coupling member 41 is connected to a by a screw 43, and the driven coupling member 42 is integrally formed with the rotary shaft 12a of the worm 12. Then, the coupling members 41, 42 are engaged with each other in a concave-convex relationship. By such Oldham coupling 40, the rotational force of the motor 25 is transmitted to the worm 12, and the worm 12 is allowed to displace the drive shaft 25a of the motor 25 in the axial direction.

Therefore, also in the second embodiment, substantially the same effect as the above-described first embodiment can be exhibited. Particularly, in the second embodiment, the Oldham coupling 40 is used in place of the key 26 described in the above embodiment. Therefore, compared with the case where the motor 25 and the worm 12 are drive-coupled by the key 26, it is not necessary to cut the key grooves 27a and 27b for engaging the key 26. As described above, it is not necessary to perform highly accurate processing, and by using the versatile and relatively inexpensive Oldham coupling 40, the electric clamp device 1
The manufacturing cost of 1 can be reduced.

(Third Embodiment) The third embodiment will be described focusing on the points different from the above-mentioned embodiment. As shown in FIGS. 6 and 7, the worm 12 has two worm wheels 3 arranged so as to face each other in the radial direction.
0 is meshed. Then, when the motor 25 rotates in a specific direction, the clamp levers 32 provided on the worm wheels 30 rotate in the directions approaching each other,
A work (not shown) is clamped by both clamp levers 32. Further, when the motor 25 rotates in the direction opposite to the clamping direction, the clamp levers 32 rotate in the directions away from each other, and the work is unclamped.
The electric clamp device 11 in FIG. 7 is shown in a state where the clamp levers 32 are arranged apart from each other, that is, in an unclamped state.

Further, in this embodiment, the fixed bearing 20 is provided below the worm 12 and the movable bearing 19 is provided above the worm 12. Further, the compression coil spring 17 shown in the above embodiment is omitted, and instead, the disc spring 50 is provided in contact with the movable bearing 19. When the clamp levers 32 clamp the work, the disc spring 50 can absorb the impact force generated at the meshing portion between the worm 12 and the worm wheel 30, and the same effect as that of the above-described embodiment is achieved. Moreover, since the disc spring 50 is smaller than the compression coil spring 17, the vertical length of the electric clamp device 11 can be made compact.

(Another Embodiment) The embodiment of the present invention may be modified as follows. -Electrical clamp device 1 shown in the first and second embodiments
1, the disc spring 50 shown in the third embodiment may be used instead of the compression coil spring 17.

In the third embodiment, the two worm wheels 30 that can rotate integrally with the clamp lever 32 are integrated into one.
Although one worm 12 is engaged with the worm 12, three or more worm wheels 30 may be engaged with the worm 12.

Next, in addition to the technical idea described in the claims, the technical idea grasped by the above-described embodiment will be shown below. (1) A plurality of worm wheels arranged so as to face each other in the radial direction are meshed with a worm that is connected to a drive shaft of a motor, and a clamp lever is integrally provided on the rotary shaft of each worm wheel. An electric clamp device that transmits a driving force to a clamp lever via a worm and a worm wheel.

[0036]

According to the present invention, when a work is clamped by a clamp lever, the impact force is absorbed, so that excessive meshing occurs at the meshing portion between the worm wheel and the worm, or tooth missing. Can be prevented.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an electric clamp device according to a first embodiment, in which (a) shows an unclamped state and (b) shows a clamped state.

FIG. 2 is a plan sectional view of the electric clamp device according to the first embodiment.

FIG. 3 is a cross-sectional view showing a connecting portion between a drive shaft of a motor and a rotation shaft of a worm in the first embodiment.

FIG. 4 is a front sectional view of an electric clamp device according to a second embodiment.

FIG. 5 is a plan sectional view of an Oldham coupling according to the second embodiment.

FIG. 6 is a front sectional view of an electric clamp device according to a third embodiment.

FIG. 7 is a plan sectional view of an electric clamp device according to a third embodiment.

[Explanation of symbols]

11 ... Electric clamp device, 12 ... Worm, 25 ... Motor, 25a ... Drive shaft, 30 ... Worm wheel, 32 ...
Clamp lever, 17 ... Compression coil spring (buffer member),
40 ... Oldham coupling, 50 ... Disc spring (buffer member).

Claims (5)

[Claims] 1. A worm is connected to a drive shaft of a motor, and a worm wheel meshed with the worm is provided with a clamp lever which rotates integrally with the worm wheel. The driving force of the motor is transmitted through the worm and the worm wheel. In an electric clamp device that transmits to a clamp lever, the worm is slidable along the axial direction of the drive shaft of the motor, and when the clamp lever clamps a workpiece, the impact generated at the meshing portion of the worm and the worm wheel An electric clamp device comprising a cushioning member for absorbing force. 2. The electric clamp device according to claim 1, wherein the cushioning member applies an elastic force in a direction in which the clamp lever clamps the work. 3. The electric clamp device according to claim 1, wherein the cushioning member is composed of a plurality of disc springs arranged in the axial direction of the worm. 4. The electric clamp according to claim 1, wherein an Oldham coupling is provided between the drive shaft of the motor and the rotation shaft of the worm. apparatus. 5. The plurality of worm wheels are provided so as to face each other in the radial direction of the worm, and the respective clamp levers approach or separate as the worm wheels rotate. The electric clamp device according to any one of the above.