JP2539580B2 - Robot hand shock absorption structure - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure for absorbing a shock from a tool side to a wrist side generated between a wrist and a tool of an industrial robot.

[0002]

2. Description of the Related Art An industrial robot is capable of processing a work by attaching a tool to the tip of its wrist, or holding a work by using a hand mechanism at the tip of the wrist to perform machining by another machine tool. The functions are diversifying, such as

For example, in the field of press work, a method in which a worker uses a dedicated jig or directly grasps a work and inserts the work into a press device to perform the work is exclusively used. With such a method, the burden on the operator is large,
In addition, safety obstacles cannot be ignored.

[0004] From the above, manufacturing has been carried out by using a dedicated holder suitable for press work.
This holder is connected to the tip of the wrist of the robot and has a hand for clamping a work. In order to prevent the impact generated by a large load during pressing from being transmitted to the robot side, a shock absorbing mechanism is provided between the hand side and the wrist side of the robot to suppress the transmission of the impact to the wrist side. ing.

[0005]

However, between the member connected to the wrist side of the robot and the hand side, for example, since the hand side makes a large bending up and down, a mechanism that allows this movement must be provided. I won't. For this reason, it is necessary not only to connect the wrist side and the hand side of the robot by the buffering means, but also to interpose a member having a certain restraint function so that the wrist and the hand of the robot become coaxial during teaching. . For such restraint, a lock mechanism is required, and as an example, there is one in which a cylinder is arranged in the center and a plurality of wires are arranged around the cylinder to lock the cylinder.

However, an excessive load easily breaks the wire or elastically deforms the wire to make the position of the hand relative to the wrist side of the robot improper.

As described above, when the holder used in the field of press work is used by being connected to the wrist of the robot, the position and posture of the hand greatly fluctuate, and the hand also moves with respect to the load. There is a problem that it is not prompt.

The problem to be solved in the present invention is to provide a shock absorbing structure having a shock absorbing function by the followability with respect to the displacement of the work and a quick restoring property.

[0009]

The present invention SUMMARY OF] is another between a base coupled to the distal end of an industrial robot wrist, and a retainer plate to secure the tool or hand, etc. for workpiece machining, with the base plate and the retainer The opposite side of
In addition, multiple connecting rings are arranged around each center in a ring shape.
Head and pressure receiving seat, the tip of the connecting rod and the pressure receiving seat
These connecting rods are installed between
Connect between them with relative freedom of rotation in three dimensions
And the connecting rod has a length in the axial direction.
And a coil spring or a cylinder interposed between the base and the center of the retainer plate to urge the base and the retainer plate in a direction to attract each other.

The pressure receiving seat may be provided with a pressure receiving hole for receiving the surface of the spherical body in a line contact state.

[0011]

By providing the connecting rods and the pressure receiving seats, which are arranged in an annular shape around the center of the sphere and receive these spheres freely rolling around their respective centers, the base and the retainer plate form a spherical joint with each other. Joined as a similar articulated structure. Further, with respect to the annular arrangement of the spherical body, the connecting rod and the pressure receiving seat, the coil spring or the cylinder attracts each other at their central portions, so that the base and the retainer plate can three-dimensionally swing. Therefore,
When the base is fixed to the robot side and the work is held by the retainer plate, even if the work is displaced during processing, the retainer plate moves following this and absorbs the impact on the wrist side of the robot. Also, the connecting rod is
Since the length in the axial direction is adjustable, the base and
Increased or decreased the distance from the Tena Plate
Retaining the base
The flexibility of changing the attitude of the naplate can also be increased.
Wear. Then, by adjusting the length of the connecting rod, the coil
The tension of the pulling can be adjusted and the posture of the retainer plate
It is also possible to correspond to the external force necessary to change the.

Further, after the displacement, the retainer plate is restrained to the base side by the coil spring or the cylinder, and at this time, the centering by the spherical body and the pressure receiving seat becomes possible, and the restoration to the original position is promptly performed. In particular, the pressure receiving seat is provided with a conical pressure receiving hole, and the spherical body is fitted into the pressure receiving hole so as to make a line contact, so that the centering is quickly performed.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a cutaway front view showing a main part of a shock absorbing structure of the present invention, and FIG. 2 is a view taken along the line AA of FIG.

In the figure, a joint 3 having a shock absorbing mechanism is incorporated between the tip of a wrist 1 of a robot and a hand 2 for clamping a work.

The hand 2 is provided with a clamper 2a which is connected to the pneumatic system on the robot side and is movable in the direction of the arrow in the figure.

The joint 3 includes a base 3a connected to the wrist 1 side of the robot via a connection plate 11 and a retainer plate 3b connected to the hand 2 side via a connection plate 12, and these are connected to bolts 3c and 3d. Are connected to the wrist 1 and the head 2, respectively.

The retainer plate 3b is provided with a total of eight pressure receiving seats 4 on the surface facing the base 3a. As shown in FIG. 2, these pressure-receiving seats 4 are arranged and fixed on a concentric circle at a constant pitch, and a pressure-receiving hole 4a which is recessed in a conical shape is provided at the tip thereof.

The base 3a is provided with four connecting rods 5 facing the pressure receiving seat 4 on the retainer plate 3b side in this example. These connecting rods 5 are provided with a block 5a fixed so as to have an axis parallel to the axis of the base 3a and a bolt 5b coaxially screwed to the block 5a. Then, by screwing the block 5a around the bolt 5b, the protruding length of the bolt 5b from the block 5a can be changed, and the axial length of the connecting rod 5 is adjusted and then locked by the nut 5c. Also, the bolt 5b
A spherical body 6 made of a steel ball is rotatably incorporated at the tip of the.

It is assumed that the four connecting rods 5 face the four receiving seats 4 provided in FIG. 2 corresponding to the apex angle of the square. Moreover, the number of connecting rods 5 may be appropriately selected according to the application.

FIG. 3 shows a sphere 6, a pressure receiving seat 4, and a connecting rod 5.
FIG. 6 is an exploded view showing the relationship with the bolt 5b of FIG.

A holding seat 5d is provided at the tip of the bolt 5b so that more than half of the circumference of the surface of the sphere 6 is dropped and the sphere 6 can roll three-dimensionally. Only the surface of the sphere 6 incorporated in the holding seat 5d is slightly smaller than half of the sphere 6 and faces the pressure receiving seat 4 side, and does not come out of the holding seat 5d even when rotated. Further, since the pressure receiving hole 4a of the pressure receiving seat 4 is recessed in a conical shape, if it comes into line contact with the spherical body 5 at the time of joining and the axis of the connecting rod 5 is twisted with respect to the pressure receiving seat 4, it Point contact can be made biased to the position on the twist direction side.

The pressure receiving hole 4a of the pressure receiving seat 4 may have various shapes, examples of which are shown in FIG.

The pressure receiving hole 4a in FIG. 4 (a) has a truncated cone-shaped tapered hole 4b on the discharge end side and an equal diameter fine hole 4c on the terminating side. FIG. 4 (b) shows the pressure receiving hole 4a. This is an example in which the entire hole 4a has a truncated cone shape. Further, (c) of the figure is an example of the pressure receiving hole 4a having a conical cross section, and four grooves 4d are carved on the inner wall thereof. In any case, it suffices that the opening area of the end face that receives the sphere 6 is the maximum and the opening area becomes gradually smaller as it goes deeper.
The inner wall of a may have a line contact relationship.

Returning to FIG. 1, in this example, a tension coil spring 7 is interposed between the base 3a and the retainer plate 3b. The coil spring 7 is hooked on hooks 3e and 3f provided at the central portions of the base 3a and the retainer plate 3b, respectively, and is substantially centered with respect to the annular arrangement of the pressure receiving seat 4 and the connecting rod 5 around the hooks. It is located. It should be noted that instead of the coil spring, a cylinder capable of generating a similar biasing force may be incorporated.

FIG. 5 is a diagram showing an outline of pressing of a work by a press device.

The work 10 held by the upper and lower clampers 2a is set on the lower mold 8 and the upper mold 9 of the pressing device. The work 10 is a lower mold 8 depending on the control system of the robot.
After being positioned above, the upper die 9 is lowered to perform press working or punching of holes by pressing.

In the above structure, the retainer plate 3b to which the hand 2 is fixed is attracted to the base 3a side by the coil spring 7. Therefore, the spherical body 6 of the connecting rod 5 is pressed into the conical pressure receiving hole 4 a of the pressure receiving seat 4. And the pressure receiving seat 4 is the retainer plate 3
a plurality of points concentrically arranged with respect to b and forming a sphere 6
Since there is a line contact around the surface of the spherical body 6 between the pressure receiving hole 4a and the pressure receiving hole 4a, the retainer plate 3b can maintain a fixed posture coaxial with the base 3a.

Therefore, the hand 2 integrated with the retainer plate 3b maintains the same posture as the wrist 1 of the robot, and the work 10 can be correctly positioned on the lower die 8. Further, even when the wrist 1 of the robot is moved up to this positioning, the hand 2 does not sway with respect to the wrist 1, and the work 1
0 can be reliably set on the lower mold 8 from the storage table or the like.

After the upper die 9 is lowered and pressed, for example, in the case of punching a hole, the work 10 may be pulled up while being combined with the upper die 9. On the other hand, the retainer plate 3b can change its posture according to the movement of the work 10 as shown in FIG. That is, the retainer plate 3b is composed of the plurality of spherical bodies 6 and the conical pressure-receiving holes 4a, and the base 3a at a plurality of points via the structure of the spherical joint.
Since the retainer plate 3b is connected to the side, the retainer plate 3b can swing three-dimensionally. Since only the tension coil spring 7 constrains the retainer plate 3b to the base 3a side, the posture of the retainer plate 3b can be freely changed with respect to the movement of the work 10.

Due to such movement of the retainer plate 3b, the hand 2 also integrally follows the displacement of the work 10. Therefore, the load or impact due to the displacement of the workpiece 10 is not transmitted to the wrist 1 side of the robot that is stopped, and the external force load on the robot side is suppressed.

A sensor is incorporated in the flange portion of the retainer plate 3b or the tip of the robot wrist.
When an abnormal external force is applied to the robot hand 2 due to an accident during work, this sensor detects the movement and causes the robot to make an emergency stop.

Further, as shown in FIG. 6, the retainer plate 3b
Even if the posture of the upper mold 9 is changed, when the constraint between the upper die 9 and the work 10 is released, the coil spring 7 is restored to cause the state shown in FIG.
Return to the posture. At this time, the retainer plate 3b is aligned with the base 3a by the spheres 6 and the conical pressure receiving holes 4a at a plurality of points, and the restoration to the original position is quickly performed. Further, even if the connecting rod 5 may come off from the pressure receiving seat 4, the restoration can be easily performed.

Further, since the structure is only the combination of the pressure receiving seat 4 and the connecting rod 5 through the coil spring 7 and the spherical body 6 around the coil spring 7, it is more compact and lighter than the conventional one, and the maintenance and inspection is easy.

In the embodiment, the retainer plate 3b
Although the hand 2 is equipped with the hand 2, it may be replaced with an automatic tool for machining a work. Alternatively, the spherical body 6 may be incorporated on the retainer plate 3b side, and the pressure receiving hole for receiving the spherical body 6 may be provided on the connecting rod 5 side. Further, although the robot for press work is used in the embodiment, the present invention can be applied to other various work fields involving impact.

[0035]

According to the present invention, since the retainer plate is constrained to the base side by the coil spring or the cylinder and the spherical body and the pressure receiving hole are joined to each other, the retainer plate is axially oriented with respect to the base and the direction orthogonal thereto. Is restrained. For this reason, positioning when setting the work is surely performed, and the same operation as handling with high rigidity becomes possible.

Further, even when the work is displaced during machining, the retainer plate follows this, so that the impact on the robot side is absorbed, and when the coil spring or cylinder restores it, the function of aligning the sphere and the pressure receiving hole is improved. It can be used and a quick reset can be done automatically. Furthermore,
The axis length of the connecting rod is adjustable, so
You can easily adjust the pulling force of the pulling and cylinder,
It can be optimally used for machining operations against.

[Brief description of drawings]

FIG. 1 is a cutaway front view showing an embodiment of a shock absorbing structure of the present invention.

FIG. 2 is a view taken along the line AA of FIG.

FIG. 3 is a cutaway view showing main parts of a spherical body, a pressure receiving seat that receives the spherical body, and a connecting rod.

FIG. 4 is a schematic vertical cross-sectional view showing another example of the pressure receiving hole provided in the pressure receiving seat.

FIG. 5 is a schematic view showing setting of a work on a press device.

FIG. 6 is a schematic view showing a state of displacement on the retainer plate side.

[Explanation of symbols]

1 Wrist 6 Sphere 2 Hand 7 Coil Spring 3 Joint 8 Lower Mold 3a Base 9 Upper Mold 3b Retainer Plate 10 Workpiece 4 Pressure Seat 11 Connection Plate 4a Pressure Hole 12 Connection Plate 5 Connecting Rod 5d Holding Seat

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yasuhisa Kubota, 2-90 Sakaigawa, Nishi-ku, Osaka City Condtech Co., Ltd. (72) Fumihiko Kawano 2-2-90 Sakaigawa, Nishi-ku, Osaka Condtech Co., Ltd. (56) References Actually open flat 5-29692 (JP, U) Actually open 64-4589 (JP, U)

Claims (2)

(57) [Claims] And 1. A base for connecting to the tip of the industrial robot wrist, and a surface facing each other between the retainer plates fixed a tool or hand, etc. for workpiece machining, with the base plate and the retainer Around each center
A plurality of connecting rods and pressure receiving seats arranged in a ring,
These are installed between the tip of the contact rod and the pressure receiving seat.
Relatively three-dimensional between the connecting rod and the pressure receiving
And a sphere that is connected with the degree of freedom of rotation,
The rod is adjustable in its axial length, and further provided with a coil spring or a cylinder interposed between the base and the center of the retainer plate for urging the base and the retainer plate in a direction to attract each other. Shock absorption structure for robot hands. 2. The shock absorbing structure for a robot hand according to claim 1, wherein the pressure receiving seat includes a pressure receiving hole that receives the surface of the sphere in a line contact state.