JPH0310476B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a robotic hand wrist device.

The robot hand wrist device of the present invention divides the wrist of the hand provided at the tip of the arm of the robot hand into two parts, upper and lower, and connects the two parts with an elastic member to provide flexibility in wrist movement. It is characterized by the fact that

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

FIG. 1 is an explanatory diagram of a robot hand mechanism that implements the present invention, where 1 is the main body of the robot mechanism, 2 is a robot arm protruding from the main body 1, 30 is the upper part of the wrist of the hand provided at the tip of the arm 2, 40 is the lower part of the wrist, and 5 is the finger of the hand.

Let us now assume that the robot hand mechanism shown in Figure 1 is used to assemble parts, and in this case, a typical example is a hole made in part B placed on a table as shown in Figures 2 a to c. A case will be explained in which the rod A is held at C by a robot hand and inserted into the hole C.

Figure 2a shows the case where the center of hole C and the center of rod A are completely aligned, and the center line is not tilted.
It is easy to insert rod A into hole C as shown by the arrow. Figure 2b shows a case where the center of rod A is shifted by δ from the center of hole C, and if part B is firmly fixed on the table and the robot hand that grips rod A has strong rigidity. In some cases, inserting rod A in the direction of the arrow will create a large resistance, and in some cases, insertion may become impossible. Figure 2c
is a case where the center line of hole C and the center line of rod A are tilted, and even in this case, if part B is firmly fixed on the table and the robot hand that grips rod A has strong rigidity. Then move stick A in the direction of the arrow.
Inserting the device may cause a large amount of resistance, and in some cases, insertion may become impossible. Figure 2 b and c
In order to avoid the situation where insertion is impossible as shown in (1) insert rod A into the inner diameter of hole C provided in part B.
Figure 2 b, c.
Even in cases like the one shown in Figure 2, insertion can be made easier if the size difference is set so that it can be inserted easily, but if the size difference between the parts is too large, the relative positions will vary, making it difficult to insert the parts precisely. Assembly cannot be realized. Another method is to increase the positioning accuracy of the robot hand that grips the rod A so that the center of the hole C formed in the part B and the center of the rod A are completely aligned, as shown in Figure 2a. There is no problem if the rod A is inserted into the hole C, but increasing the positioning accuracy of the robot hand requires a large amount of cost and is also a factor that generally reduces the speed, as shown in Figure 2 c. If the center lines of the hole C and the rod A are inclined as shown in the figure, there is a drawback that the control device is further complicated and the difficulty is further increased.

The present invention provides a robot hand mechanism that can easily perform the insertion work even in the cases shown in FIGS. 2b and 2c, except for the drawbacks of the prior art as described above. An example is shown below.

In the present invention, a cylindrical projection 32 is implanted approximately in the center of the lower end surface 31 of the upper wrist portion 30, and this is inserted into a hole 42 provided approximately in the center of the upper end surface 41 of the lower wrist portion 40.
An annular elastic body 35 such as rubber is inserted into the gap 34 formed between the inner peripheral surface of the hole 42 and the outer peripheral surface of the cylindrical projection 32.
The center of the lower wrist 40 and the center of the upper wrist 30 are kept substantially aligned by the elasticity of the wrist. Further, a nut 33 is screwed onto the tip of the cylindrical projection 32 passing through the hole 42, and a spring 43 is inserted between the upper wrist 30 and the lower wrist 40 on the outside of the cylindrical projection 32, and both end surfaces of the spring 43 are inserted. The lower end surface 31 of the upper wrist 30 and the upper end surface 41 of the lower wrist 40
The lower end surface 31 of the upper wrist 30 and the upper end surface 4 of the lower wrist 40 are brought into contact with each other by the tension of the spring 43.
1, and on the outside of this spring 43, both ends of the bellows 44 are fixed to the upper wrist 30 and the lower wrist 40 via fixing fittings 36 and 45, respectively.

Furthermore, the inside of the wrist upper part 30 is hollow, and a switch 38 is provided therein, with its operating rod 37 penetrating the lower end surface 31 of the wrist upper part 30 and protruding so as to face the upper end surface 41 of the wrist lower part 40. The lower end of the operating rod 37 is disposed on the upper end surface 41 of the lower wrist portion 40 with an appropriate space therebetween.

As described above, in the robot hand and wrist device of the present invention, the wrist portion is separated into an upper portion 30 and a lower portion 40, which are connected by a bellows 44 that can be expanded and contracted in the vertical direction. A hole 4 in which a cylindrical projection 32 is provided in the lower wrist 40
The nut 33 is screwed onto the tip of the cylindrical protrusion 32 that has passed through the hole 42, and the nut 33 is inserted into the lower wrist 4.
0 does not separate from the upper wrist 30, and a spring 43 is inserted between the upper wrist 30 and the lower wrist 40, and its tension increases the distance between the upper wrist 30 and the lower wrist 40. has been
In addition, the elasticity of the annular elastic body 35 provided in the hole 42 acts so that the center of the hole 42 in the lower wrist portion 40 coincides with the center of the cylindrical projection 32. Therefore, when the robot hand arm 2 is stationary at a certain position, if some force is applied to the lower wrist 40, the lower wrist 40 will receive a restoring force due to the stretching force of the spring 43 in the axial direction, and in a direction perpendicular to the axis. is an annular elastic body 3
Since the restoring force of 5 acts on each wrist, it can move relative to the upper wrist 30 as shown in FIGS. 4a and 4b depending on the strength of the force.

In the case shown in FIG. 4a, the lower wrist 40 receives a force directed to the right in the horizontal plane from the upper wrist 30, and the hole 42 moves to the right against the elasticity of the annular elastic body 35, causing the hole 42 to move to the left side. is shown abutting the cylindrical protrusion 32, and the lower wrist 40 can move within the gap 34 by a substantially equal amount δ. Figure 4b shows that the center of the lower wrist 40 can be inclined at a certain angle with respect to the center of the upper wrist 30, and the circle of the upper wrist into which the inner diameter of the hole 42 provided in the lower wrist 40 is inserted. Since the outer diameter of the columnar projection 32 is larger than that of the columnar projection 32, the lower wrist 40 is connected to the upper wrist 30.
When tilted with respect to
It can be tilted within an angle θ determined by the thickness of the upper end portion of 0. In this case, the restoring force is caused by both the spring 43 and the annular elastic body 35, and acts to return the lower wrist 40 to its original position.

Considering the case where the robot hand that adopts the wrist mechanism shown in Fig. 3 performs the assembly work shown in Fig. 2 a to c, in the case of Fig. 2 b, the 4th
As shown in Figure a, the lower part of the wrist holding the rod A moves to the right by δ and can be inserted along the hole C, making insertion easier. That is, the accuracy of the positioning device that moves the rod A onto the hole C can have an error of δ, which has the advantage that the accuracy of the positioning control device for the robot arm can be slightly lowered. Also, as shown in Figure 2c, if the center line of the hole C is inclined with respect to the center line of the rod A, the fourth
This is achieved by allowing the lower part of the wrist to be tilted as shown in Figure b, and the center line of the rod A can be aligned with the center line of the hole C to facilitate insertion. Also, the force when inserting the rod A is applied to the spring 4 from the upper part of the wrist 30.
3 to the lower wrist 40 and then to the rod A. Therefore, if the resistance during insertion is large, the spring 43 will be compressed to generate an insertion force, and if the insertion resistance exceeds the limit, the force will be applied to the lower wrist 40. The tip of the operating rod 37 of the switch 38 comes into contact with the upper end surface 41, and the operating rod 3
7 is pushed up and actuates the switch 38, which acts to stop the action of pushing down the robot arm.

As described above, according to the present invention, only one set of the elastic body 35 and the spring 43 is provided, and the movement of the wrist can be controlled in three ways.
It is possible to provide dimensional flexibility, the structure can be made extremely simple, and since these are surrounded by bellows 44, dust does not enter the wrist mechanism, which has the great advantage of extending its life. be.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of a robot hand mechanism implementing the present invention, FIGS. 2 a to c are explanatory diagrams of assembly work of parts, respectively, FIG. 3 is a sectional view of the device of the present invention, and FIGS. 4 a,
b is an explanatory diagram of the operation. 1...Body part, 2...Arm, 30...Upper wrist, 3
1...Lower end surface, 32...Protrusion, 33...Nut, 34...
Gap, 35...Elastic body, 36...Fixing metal fitting, 37...Operation rod, 38...Switch, 40...Wrist lower part, 41...
Upper end surface, 42...hole, 43...spring, 44...bellows, 45...fixing bracket, A...rod, B...parts, C
…hole.

Claims (1)

[Claims] 1 Consisting of an upper wrist fixed to the arm of a robot hand and a lower wrist to which the base of a finger mechanism for gripping a workpiece is fixed, a cylindrical projection protrudes from the upper wrist toward the lower wrist, and the wrist The cylindrical projection is inserted into a hole with a larger diameter than the cylindrical projection provided at the top of the lower part, and an annular elastic body is inserted between the outer periphery of the cylindrical projection and the hole, and the outer side of the cylindrical projection is inserted. A spring is inserted between the upper wrist and the lower wrist, and the tension of the spring is used to restrain the upper wrist and the lower wrist from separating from each other, and to create a space between the upper wrist and the lower wrist. A robot hand wrist device characterized in that these are connected by bellows.