JPH05305506A - Chuck device - Google Patents

Abstract

PURPOSE:To provide a chuck device which can always centeringly hold the center position of a work in a decided position regardless of variation of the sort and size of the work, can adjust the gripping force against the work, and can deal with the work of various material. CONSTITUTION:This chuck device supports over three pieces of claws 1 so as to be movable in the radial direction of a work 2 and at regular intervals, and it is provided with an actuator 3 which can control to independently move respective claws 1, a detecting means 4 to detect contact of the claws 1 with the work 2, and a control device 5 to control advancing and retreating of the claws 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cylindrical or disk-shaped work in a robot hand, an automatic assembly machine, an automatic processing machine, etc. The present invention relates to a chuck device that always keeps the center position at the same position.

[0002]

2. Description of the Related Art Conventionally, as a chuck device of this kind, a scroll chuck using a spiral groove, a collet chuck using a taper, etc. have been widely used in a working mechanism. These are suitable for holding a cylindrical or disk-shaped member with high precision and high force.

A robot hand for gripping a circular member is disclosed in, for example, Japanese Patent Laid-Open No. 3-178794. In the above invention, the rotary operation plate 71 rotatably provided with respect to the base portion 70, and the movable finger 73 held by the guide 72 attached to the base portion 70 so as to be slidable in the radial direction of the circular member. A link mechanism 74 having one end rotatably attached to the rotary operation plate 71 and the other end rotatably attached to the movable finger 73, and one actuator 75 for rotating the rotation operation plate 71 with respect to the base portion 70. It is configured.

In the robot hand having the above-mentioned configuration, the rotary operation plate 71 is rotated by the operation of the actuator 75, and the movable finger 73 is simultaneously gripped or released via the link mechanism 74.

[0005]

However, each of the above-mentioned prior arts has the following drawbacks. That is, in the scroll chuck or collet chuck, it is possible to perform centering with high accuracy, but since the gripping force is strong, a work made of a material having relatively low strength such as plastic or glass,
When trying to center and hold a disk-shaped work with a thin plate thickness, the work was damaged and was not suitable.

Further, in the method using the rotary operating plate and the link mechanism described in Japanese Patent Laid-Open No. 3-178794, although the gripping force can be easily adjusted, the centering accuracy depends on the accuracy of the rotary operating section and the link mechanism. For this reason, it is difficult to perform high-precision centering, and there is a drawback in that if an attempt is made to increase the centering precision, the center becomes large and heavy, which makes it impractical.

Therefore, the present invention was developed in view of the drawbacks of the above-mentioned respective prior arts, and the gripping force can be easily adjusted, and a cylindrical or disk-shaped work can be processed in various types and sizes. It is an object of the present invention to provide a chuck device having a highly accurate centering function capable of centering and holding a center position of a work at a constant position regardless of a change in diameter due to variation in

[0008]

FIG. 1 is a conceptual diagram of a chuck device according to the present invention. The present invention is an actuator configured to support a plurality of at least three claws 1 movably in the radial direction of a work 2 at equal intervals, and to independently control the movement of each claw 1 in the radial direction. 3, a detecting means 4 for detecting that the claw 1 is in contact with the work 2, and a control device 5 for controlling the forward and backward movement of the claw 1.
It is equipped with and.

According to the present invention, each claw 1 is moved by the same movement amount in the direction in which the work 2 is gripped by the actuator 3, and when the detection means 4 detects that all the claws 1 are evenly contacted with the work 2. , The work 2 is centered and held by stopping the movement of the claw 1.

[0010]

Embodiment 1 FIGS. 2 to 6 show this embodiment, FIG. 2 is a perspective view of a robot hand, FIG. 3 is an enlarged perspective view of a claw portion, and FIG. 4 shows a signal flow of this embodiment. FIG. 5 is a block diagram, FIG. 5 is a flowchart showing the control procedure, and FIG. 6 is a graph showing the relationship between the number of pulses sent to the servomotor and the output of the amplifier.

The present embodiment is an example in which the present invention is applied to a robot hand. The support shaft 12 of the robot hand 11 is connected to a drive shaft (not shown) of a robot (not shown), and is configured so that it can move vertically and horizontally and rotate around the support shaft 12 by the operation of the robot. ing. A disk-shaped upper support plate 13 is attached to the support shaft 12.
A circular lower support plate 15 is fixed to the support plate 13 via three suspension shafts 14 standing upright at equal intervals in the circumferential direction.

Therefore, in each suspension shaft 14, a spring 18 is interposed between fixing members 16 and 17 having upper and lower ends of the coaxial shaft 14 fixed to the upper and lower support plates 13 and 15, respectively. The pressing force from below applied to the lower support plate 15 can be absorbed by the elastic force of the spring 18 of each shaft 14. The lower support plate 15
On the upper side of the
1, 22, and 23 are attached, and a pinion 33 is fixed to the drive shaft of each servo motor 21, 22, 23. Guide rails 27, 28 and 29 are fixed to the lower side of the lower support plate 15.

Slide members 30, 31 and 32, which are movable along the length direction of the guide rails 27, 28 and 29, are mounted, and the slide members 30, 31, 32 are claws 37 by springs 24, 25 and 26. , 38 and 39 are urged in the opening direction so as to eliminate backlash between the rack 34 and the pinion 33.

Further, each slide member 30, 31, 32
A rack 34 that meshes with the pinion 33, an arm 36, and claws 37, 38, 39 are attached via a support member 35. As shown in FIG. 3, one of the three arms 36 has three claws 37, 38, 39.
Strain gauge 40 for detecting even contact with the
Is installed.

As shown in the block diagram of FIG. 4, this strain gauge 40 is connected to a control device 42 via an amplifier 41 so that the strain of the arm 36 by the force applied to the pawl 37 can be measured. .. In addition, three servo motors 21,
22 and 23 are also connected to the control device 42, and are configured so that the three claws can be independently advanced and retracted by a command from the control device.

In the apparatus constructed as described above, when the work 19 is centered and held by the robot hand 11, each servo motor 21, 22, 23 is rotated in a predetermined direction, and the slide members 30, 31, 32 are moved by the arm 36. Move in the opening direction and move to the origin position. At this origin position, the claws 37, 38, and 39 are previously attached to the support shaft 12 of the robot hand 11.
It is adjusted to a position that is equidistant from the central axis of.

Next, as shown in the flow chart of FIG. 5, each servo motor 21, 22, 23 is given a movement command pulse by pulse to move forward, that is, to move the work 19 in a chucking direction. Here, at the time when one movement is completed, the output of the strain gauge 40 is transmitted to the control device 42 via the amplifier 41.
Take in. When the claws 37, 38 and 39 are not yet in contact with the work 19, the output of the amplifier 41 is small as shown by A in the graph of FIG. That is, the chucking of the work 19 has not been completed yet.

By repeating this operation, each servo motor 2
When 1, 2, 22 and 23 are moved by the same distance and the chuck is closed, one of the claws 37, 38 and 39 moves to the work 19
, The work 19 is pushed by the claws 37, 38, 39 to move, and when the three claws 37, 38, 39 evenly contact the work 19, the arm 36 begins to bend, and the amplifier 41 of the amplifier 41 moves. The output begins to grow as shown in Figure 6B.

The claws 37, 3 are previously attached to the control device 42.
If the threshold value for determining that the workpieces 8 and 39 contact the work 19 is set to, for example, the level of C in FIG. 6, when the output of the amplifier 41 reaches this level, the work 19 is controlled with a predetermined force. Since it can be centered and held, the centering operation of the robot hand 11 is completed here. At this time, if the threshold value for determining that the claws 37, 38, 39 have contacted the work 19 is set as shown in D of FIG. 6, the work 19 can be gripped with a stronger force.

According to this embodiment, the gripping force can be easily adjusted only by changing the threshold value of the output signal of the amplifier 41.

[0021]

Second Embodiment FIG. 7 is a block diagram showing this embodiment.
In this embodiment, the strain gauge 40 and the amplifier 41, which constitute the detection means in the first embodiment, are eliminated, and instead, as the detection means for detecting the contact of the three claws with the work, the three servo motors 21, 22 and 23 is different in that a current detection device 43 is provided in the middle of one of the drive current lines, and the other components are similar to each other. However, the description of the configuration is omitted.

The basic operation of the device having the above-described structure is the same as that of the first embodiment, but in the first embodiment, when the three claws 37, 38, 39 come into contact with the work piece 19, the strain gauge 40 is operated. The output signal of the amplifier 41, which has amplified the output, changes as shown in FIG. 6 depending on the number of pulses applied to the servo motors 21, 22, and 23. On the other hand, in the present embodiment, the output signal of the current detection device 43 changes as shown in FIG. That is, the servo motors 21, 22, 23 are set to 1
If a command to move each pulse is issued and the claws already come into contact with the workpiece and cannot move forward any further, the deviation from the commanded coordinate values becomes large, and as a result, the servomotors 21, 22, 2
The current flowing through 3 increases. The change of the current is detected by the current detecting device 43, and the contact of the nail is detected by setting the threshold value as in the first embodiment. Here, the advance of the servomotors 21, 22, and 23 is stopped to complete the centering.

According to this embodiment, the strain gauge and the amplifier for amplifying the signal as in the first embodiment are not required, and the contact of the nail is detected only by the current detecting device, so that the mechanical structure is simple. You can

[0024]

Third Embodiment FIGS. 8 to 11 show the present embodiment, FIG. 8 is a schematic configuration diagram, FIGS. 9 and 10 are detailed diagrams of a detection device, and FIG.
FIG. 1 is a plan view showing a state in which the present embodiment is applied to a square work. This positioning chuck 50 has four claws 5.
Two sets of 1 are arranged at right angles to each other so as to sandwich two works 52. The pawl 51 is held by a guide 57 so as to be movable in the radial direction of the work, and is fitted with a feed screw 58 via a nut (not shown).
The feed screw 58 can be rotated by the servo motor 53 via the large pulley 55, the belt 56, and the small pulley 54. By giving a command from the control device 60 to the servo motor 53, the four claws 51 can be independently and arbitrarily set. It is configured so that it can be moved to a position.

A detecting device 59 for detecting that the claw 51 has come into contact with the workpiece 52 is incorporated in one of the two sets of the two claws 51 facing each other. This detection device 5
9 is shown in detail in FIG. The tip 61 is held by the claw 51 so as to be movable in the same direction as the moving direction of the claw 51, and is biased by a spring 63 in a direction of chucking the work piece 52. A contact 62 is fixed to the claw 51, and a contact 64 is fixed to the tip of the contact 62.
The claw 51 containing the detection device 59 is made of a non-conductive material, and the tip 61, the contact 62 and the contact 64 are provided.
Is a conductive material, and the spring 63 and the contact 62 are insulated.

Although the basic operation of the device having the above-described structure is the same as that of each of the above-described embodiments, in this embodiment, two pairs of claws 51 are arranged in two directions at right angles, and the detection device is provided in each pair. 5
It is characterized by having 9. That is, in this embodiment, it is possible to send a command pulse to the servo motor 53 for each pair of the claws 51 to perform the chuck operation of the work piece 52.

Further, in the detection device 59, when the tip tip 61 comes into contact with the work 52 and further comes into contact with the opposing claw 51 and is pushed, the spring 63 is compressed and the tip tip 61 is pressed.
Touches the contact 64 of the contact 62, and the state shown in FIG.
By short-circuiting between the terminals A and B, the work 52
The contact between the finger and the claw 51 is detected. If the command pulse to the servo motor 53 is stopped based on the signal of the detection device 59 for the two sets of the claws 51, the centering and holding of the work 52 is completed. The amount of force that grips the workpiece 52 can be adjusted by changing the spring constant of the spring 63.

According to this embodiment, as shown in FIG. 10, a square or rectangular work piece 52 can also be chucked. Further, since the two axes can be independently moved, by giving the opposite servo motors 53 the same amount of movement commands in opposite directions, the position of the work 52 can be moved from the original centered position to an arbitrary distance. It is possible to shift and position them.

[0029]

As described above, according to the chuck device of the present invention, the center position of a cylindrical or disk-shaped work can be adjusted regardless of the change in diameter due to variations in work type or size. It is possible to provide a chuck device having a highly accurate centering function of always centering and holding the centered position. Further, by adjusting the force amount of the actuator, the detection sensitivity of the detection means, and the spring force amount, the gripping force of the work can be adjusted, and it is possible to deal with works of various materials.

[Brief description of drawings]

FIG. 1 is a conceptual diagram showing the present invention.

FIG. 2 is a perspective view showing a first embodiment.

FIG. 3 is an enlarged perspective view showing the first embodiment.

FIG. 4 is a block diagram showing a first embodiment.

FIG. 5 is a flowchart showing the first embodiment.

FIG. 6 is a graph showing Example 1.

FIG. 7 is a block diagram showing a second embodiment.

FIG. 8 is a schematic diagram showing a third embodiment.

FIG. 9 is a detailed view showing the third embodiment.

FIG. 10 is a detailed view showing the third embodiment.

FIG. 11 is a plan view showing a third embodiment.

FIG. 12 is a plan view showing a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Claw 2 Work piece 3 Actuator 4 Detection means 5 Control device

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI technical display location B25J 15/08 K 8611-3F

Claims (1)

[Claims] 1. A chuck device for gripping an outer diameter or an inner diameter of a cylindrical or disk-shaped work, at least three claws movably supported at equal intervals in the radial direction of the work, and each claw. An actuator that independently controls the movement of the work in the radial direction, a detection unit that detects that the claw contacts the work, and a control device that controls the forward and backward movement of the claw based on a signal from the detection unit are provided. A chuck device.