JPS5953181A - Mechanical hand of industrial robot - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a mechanical node of an industrial robot, and more particularly to an improvement in the mechanical node of an industrial robot necessary for assembling a workpiece to a predetermined mounting portion.

Generally speaking, as an example of this type of work assembly work, we will take as an example the work of assembling a strut assembly (hereinafter referred to as strut) for a strut-type front suspension of an automobile.A vehicle body that has been conveyed on a conveyor is stopped at a predetermined position. On the other hand, the movement trajectory of the robot is taught in advance, and after gripping the workpiece (strut) with a mechanical hand attached to the robot, the robot is operated based on the teaching information to attach the workpiece to the vehicle body. A system that can be assembled to a certain part is conceivable.

As shown in FIG. 1, a conventional mechanical hand H used in such a system includes a main body 1 that is connected and fixed to a robot, and a pair of clamp arms 2 that are installed at the tip of this main body 1 and grip a workpiece. The clamp arm 2 was connected via a link mechanism 4 to a piston rod 3a of an air cylinder 3 attached to the main body 1, and was configured to open and close as the piston rod 3a moved forward and backward. .

By the way, in the above-mentioned system, the accuracy of the stopping position of the vehicle body is limited by the current control technology and is generally lower than the accuracy of the robot's movement.
Moreover, since the workpiece gripped by the mechanical hand H moves integrally with the robot, the relative positional relationship between the workpiece and the mounting portion of the vehicle body becomes out of order, making it difficult to assemble the workpiece.

As a means to solve such a problem, as shown by the two-dot chain line in FIG. The workpiece is elastically supported by a guide means not shown in the drawings, and the workpiece is guided to the attachment site of the vehicle body, and the relative movement of the workpiece at that time is absorbed by the elastic deformation of the elastic plate t. I can think of things.

However, in such a conventional mechanical hand, in order to reliably grip the workpiece without dropping it during transport, the elastic plate 5 is
It is necessary to reduce the elastic modulus of
The amount of elastic deformation of the elastic plate 5 becomes small,
A sufficient amount of relative movement of the workpiece cannot be ensured during one-way assembly, resulting in a problem that the workpiece cannot be assembled to a predetermined portion of the vehicle body.

The present invention has been made based on the above-mentioned viewpoints, and its purpose is to prevent the relative positional relationship between the workpiece and its mounting portion from becoming distorted without impairing the gripping condition of the workpiece. Moreover, when assembling the workpiece to the mounting part using a predetermined guide means, the mechanical hand of the industrial robot is capable of assembling the workpiece by absorbing deviations in the relative positional relationship between the workpiece and the mounting part. Our goal is to provide the following.

The gist of the present invention is to provide a main body that is fixed to a robot, a clamp member that is provided on the main body and that holds a work piece in a floating manner, and a clamp member that holds the work piece so as to restrain the movement of the work piece. An industrial robot that is equipped with a locking member for fixing the workpiece, and effectively prevents the workpiece from wobbling due to the action of the locking member when transporting the workpiece, and also floats the workpiece when assembling the workpiece so that no load is applied to the robot. In the mechanical hand.

Hereinafter, the present invention will be described in detail based on embodiments shown in the accompanying drawings.

FIG. 2 is a perspective explanatory view showing an outline of the assembling process of a strut, which is a workpiece. In FIG. 2, the vehicle body B is placed on a conveyor 10 and moved, and is positioned when it reaches the strut assembly position. A robot )R for transporting stock )P is installed, and a mechanical hand H for grasping stock )P is attached to the tip of the multi-joint arm 11 of robot )H.

Then, the robot (R) transports the stock (P) to a predetermined position based on predetermined teaching information, and then fits the upper case 14 of the stock (P) into the positioning hole 13 on the upper surface of the strut tough-12. The strut P is set at the assembly position by passing an assembly bolt 16 erected on the upper case 14 through the bolt insertion hole 15 on the upper surface of the strut tower 12. Furthermore, the stock) P set at the assembly position tightens the nut 17 on the assembly bolt 16 of the strut P using a nut tightening device N attached to another robot R/, thereby tightening the nut 17 on the vehicle body B. It is now fixed to . still,
In FIG. 1, reference numeral 18 indicates a temporary holding table for temporarily holding the strut P, and reference numeral 19 indicates a nut supply device for supplying the nuts 11 to the nut tightening device N.

In this embodiment, the mechanical hand H that grips the strut P is as shown in FIGS. 2 to 6.
The main body 20 is fixed to the arm 11 of the robot (robot) H, and the shaft part Ps of the strut P provided on this main body 20 is capable of floating the strut P in a plane parallel to the vehicle body mounting surface (the upper surface of the strut tower 12). It is comprised of a clamp member 21 that grips the strut P, and a lock member 22 that fixes the clamp member 21 so as to restrict the movement of the strut P.

As shown in FIG. 4 and FIG.
1, and a support shaft 25 coaxially with the arm 11 of the robot R and supporting one end of the stop P is attached to the hole 23a of the base plate 23 so as to be slidable in the vertical direction. A stopper portion 26 is provided at the lower end of the support shaft 25, and the upper end flange 25a of the support shaft 25 and the base plate 2
A spring 2T is interposed between the support shaft 25 and the support shaft 25 to constantly urge the support shaft 25 upward. A column 28 is erected on the base plate 23 in parallel with the support shaft 25. A detent plate 29 is protruded from the support shaft 25 side of the column 28, and the shaft portion ps of the strut P is The fixing bracket Pb protruding from the top is shaped like a clothes box M. Furthermore, a pair of cylindrical portions 30 are formed on both sides of the upper part of the support column 28 in the front and back direction, and a support rod 32 is attached to each cylindrical portion 30 via a ball bushing 31 so as to be slidable in the axial direction. A stopper portion 33 is provided at the lower end of the support rod 32.
At the same time, a mounting bracket 34 for the clamp member 21 is mounted on the upper part of the support rod 32, and a spring 35 is interposed between the mounting bracket 34 and the cylindrical portion 30 so that the support rod 32 is always raised upward. It is designed to be energized by

Further, as shown in FIGS. 3 and 6, the clamp member 21 includes a pair of movable arms 31 that are pivotally attached to the mounting bracket 34 with a pivot 36 and that open and close in a plane parallel to the base plate 23. movable arm 37
A pair of 70-ting mechanisms 38 are provided at opposing portions of the
and an abutment plate 39 that is attached to the shaft portion ps of the strut P and comes into contact with the shaft portion ps of the strut P. In this type, the movable arm 37 and the abutment plate 39 each have an expanded angular U-shape and are arranged symmetrically, and each floating mechanism 38 are provided between the expanded portions of the strut P, and are arranged every 90° in the radial direction of the shaft portion P8 of the strut P.

The floating mechanism 38 is configured to move the movable arm 3
A spherical bearing 41 is fitted and fixed in the mounting hole 40 of No. 7, a sleeve 43 is pivotally supported by the spherical bearing 41 via a hollow spherical shaft 42, and a sleeve 43 is slidably mounted through the sleeve 43. a sliding body 44, a spherical bearing 46 fitted and fixed in the mounting hole 45 of the support plate 39, and a shaft that is pivotally supported by the spherical bearing 46 via a hollow spherical shaft a→, and at the tip of the sliding body 44. It is interposed between the connecting body 47 to be connected and fixed, the washer 4B attached to the tip of the sliding body 44, and the 7 langes 43a integrally provided on the sleeve 43, and the sliding body 44 is stocked. It is composed of a spring 49 that urges toward the axis Po, and a stop washer 50 that is provided at one end of the sliding body 44 and comes into contact with one end of the sleeve 43 to restrict the amount of movement of the sliding body 44. In FIG. 6, 51 and 52 are retaining rings for fixing the spherical bearings 42 and 46, and 53 is a nut for fixing the sleeve 43.

A pair of air cylinders 54 for driving the clamp member 21 are attached to the mounting bracket 34, and the piston rods 54a of each air cylinder 54 are connected to the base end of the movable arm 37, so that the piston rods 54a can be moved back and forth. The movable arm 37 opens and closes in response to movement. Further, a bolt stopper 55 is provided protruding from opposite sides of the movable arm 37, and this bolt stopper 55 comes into contact with a stopper piece 56 provided on the mounting bracket 34 to restrict the closed position of the movable arm 37. It has become.

Further, as shown in FIGS. 2 and 6, the locking member 22 has a pair of locking members attached to the outside of each movable arm 31 and having a piston rod 57a that moves back and forth in the radial direction of the shaft portion ps of the strut P. The air cylinder 57 and the piston rod 57 of the air cylinder 57 opened in the movable arm 37
The piston rod 5 is inserted into the insertion hole 58 through the pole bushing 59 and the piston rod 5 is inserted into the insertion hole 58 through which the piston rod 5 is inserted.
When the piston rod 57a protrudes, the adapter 60 contacts the side surface of the movable arm 37 of the contact plate 39, and presses the contact plate 39 against the shaft Ps of the strut P. Therefore, the clamp member 21 is fixedly supported.

Therefore, to explain the case where the mechanical hand H of the industrial robot according to this embodiment is used to assemble the strut P to the vehicle body B, first, as shown in FIG.
After gripping the strut P placed on the temporary stand 18 with the mechanical hand H, the strut P is placed on standby at a position where it will not interfere with the vehicle body B being transferred on the conveyor Ib. In this process, first, as shown in FIGS. 3 and 6, the pistol hand H of the air cylinder 54 of the mechanical hand H is moved to the temporary storage stand 18 by a command signal from a control device (not shown). After moving the strut P upward and placing the main body 20 facing downward, the mechanical hand H is lowered and stopped at a position where the bottom of the strut P contacts the support shaft 25 and the spring 27 balances the weight of the strut P. do. After that, by a command signal from a control device not shown,
The piston rod 54a of the air cylinder 54 moves backward, the clamp member 21 closes, and the contact plate 39 contacts the shaft portion Ps of the strut P. Then, since the piston rod 57a of the air cylinder 57 constituting the locking member 22 operates to protrude, the adapter 60 comes into contact with the outer surface of the contact plate 39, and the contact plate 39 is pressed against the shaft portion P8 of the strut P. In particular, the strut P is connected to the clamp member 21.
It is grasped by Isosumi. In this state, vJ7
As shown in FIG. 8 and FIG. 8, when the arm 11 of the robot R rotates by a predetermined angle, for example, 30 degrees, the fixing bracket Pb of the stock P is inserted into the rotation stopper plate 29 of the mechanical hand H. The rotational force of 10 is transmitted to the stock P, but the assembly bolt 16 installed upright on the upper case 14 of the strut P is
Since the assembly bolt 16 is fitted into the positioning slit 61 opened at 8, the entire stock P rotates while the assembly bolt 16 moves within the positioning slit 61, and the assembly bolt 16 is inserted into the positioning slit 61. After contacting the end portion of the strut 61, only the shaft portion Pa of the strut P rotates, and the upper case 14 rotates idly. Therefore, the relative positional relationship between the assembly bolt 16 and the robot R is uniquely determined, and in this state, the robot R pulls out the stock P from the temporary stand 18 and stands by at a predetermined position. In addition, in Fig. 7 and Fig. 8, 62 is stock) P
A fitting hole 63 provided in the temporary holder 18 so as to fit the upper case 14 portion of the strut P is a clip that holds the shaft portion ps of the strut P.

Next, when the vehicle body B stops at a predetermined position, a vehicle body stop completion signal is issued from the external control device (not shown), and the assembly bolt 16 is inserted into the lower position of the strut tower 12. The strut P is conveyed and stopped so that it faces upward. At this time, the mechanical hand H grips the strut P so as to restrict the movement of the strut P, so that the strut P does not shake when the strut P is conveyed. The strut P transported in this way
Since the accuracy of the stopping position of the vehicle body is lower than the operating accuracy of the robot (H), it is generally shifted in the longitudinal direction of the vehicle body with respect to the position of the positioning hole 13 of the vehicle body B. In this embodiment, the positioning hole 13 of the strut P and the vehicle body B is
In order to correct the deviation, guide means G as shown in FIG. 9 is arranged. This guide means G is provided to be able to move forward and backward in the vertical direction, and is normally positioned and fixed at a position facing the upper part of the strut P, but when desired, it is moved parallel to the single mounting surface of the strut P. It is set in a floating state on a plane and fixed at an arbitrary position. Therefore, the guide means G
, a shaft 64 that moves forward and backward in the vertical direction, and a positioning hole 1 fixed to the tip of the shaft 64 in the vehicle body B.
a guide member 65 that self-centripetally engages with the upper case 14 of the strut P; and an engagement member 67 that engages with a retaining hole 66 that is movably provided at the tip of the guide member 65 and that is provided in the upper case 14 of the strut P. and springs 68 and 69 that always urge the guide member 65 and the engaging member 6γ downward.

In this state, when the guide means G moves downward, as shown in FIG.
The engagement member 6γ is located at a position I facing the upper part of the strut P.
Since it is located at F't, it passes through the positioning hole 13 of the vehicle body B and engages with the retaining hole 66 of the upper case 14 of the stock P. At this time, the guide member 65 is arranged at a position close to the seven flange 13a on the edge of the positioning hole 13. Thereafter, as shown in FIG. 6, the locked state of the locking member 22 of the mechanical hand H is released by an engagement completion signal between the stock P and the engaging member 6T issued from a control device (not shown). That is, the piston rod 57a of the air cylinder 57 moves backward 1/, the adapter 60 comes out of contact with the abutment plate 39 of the clamp member 210, and the strut P is supported floating in the radial direction and vertical direction by the floating mechanism 3 etc. will be done. At this time, the guide means G is also set in a floating state.

Thereafter, as the guide means G moves downward, as shown in FIG.
while fitting into the positioning hole 13. At this time, the engaging member 67 will also move with the self-centripetal movement of the guide member 65, but this retaining member 6γ is pressed against the stock P by the action of the spring 69, and the stock P is floatingly supported, so the strut P
moves following the movement of the retaining member 67. In this state, the stock P is set at a position corresponding to the positioning hole 13 of the vehicle body, and at this stage the position of the guide means G is fixed.

After this, the robot)R raises the stock)P at the vehicle body assembly position 1. At this time, each assembly bolt 1 of the strut P
6 is set to be shifted in phase from each bolt insertion hole 15 of the vehicle body B by an angle of 2°, for example, as shown in FIG. Abuts against the upper and lower surfaces. In this state, the upward movement of the strut P is restrained by the vehicle body B, so the strut P itself does not rise.
Support shaft 2 provided in the main body 20 of the mechanical hand H
5 and support rod 32 move in the axial direction of strut P and against the biasing forces of springs 27 and 35, respectively.

As a result, the assembly bolt 16 of the stock P is pressed against the upper and lower surfaces of the strut tower 2 by the biasing force of the springs 27 and 35. From this state, when the arm 11 of the robot (H) rotates by a predetermined angle, for example, 4 degrees, the stock (P) rotates accordingly. At this time, the mounting bolt 16 of the strut P moves while slidingly contacting the upper and lower surfaces of the strut tower 12, and when it matches the position of the bolt insertion hole 15 of the vehicle body B, the mounting bolt 16 moves as shown in FIG. passes through the bolt insertion hole 15 due to the biasing force of the springs 27 and 35. In this case, the strut P will rotate more than the phase difference between the mounting bolt 16 and the bolt insertion hole 15 (2 degrees in this embodiment), but the mounting bolt 16 will not penetrate into the bolt insertion hole 15. After that, the rotation of the upper case 14 of the strut P will be restricted, so
Only the shaft portion Pa of the strut P will rotate idly.

In this state, the stock P is set at the position where the vehicle body B is assembled.

After that, the above assembly bolt 16 is tightened by the nut tightening device N.
The nut 17 is tightened to fix the strut P to the vehicle body B. In this state, after the clamp member 21 of the mechanical hand H is opened and the grasping state of the shaft portion P8 of the stock P is released, the robot R moves the mechanical hand H so as not to interfere with the assembled stock P. Retract and return to the original position to prepare for the next process. At this time, the guide means G also moves upward at the same time to prepare for the next step.

In the above embodiment, the main body 20 of the mechanical hand H supports the lower end of the strut P by the support shaft 25, but this support shaft 25 is not necessary and only the clamp member 21 is supported. It is also possible to grip the stock (P) using the . Further, the clamp member 21 has a 70-
Although the floating mechanism 38 is interposed therebetween, the present invention is not necessarily limited to this, and the design may be modified as appropriate, such as attaching the pair of clamp arms directly to the main body 20 via a floating mechanism. Furthermore, in the above embodiment, the floating mechanism 38 supports the stock P in a floating manner in its radial and axial directions, but the design may be modified as appropriate as long as it supports the stock P in a floating manner at least in the radial direction. do not have. Furthermore, it goes without saying that the locking member 22 for fixing the clamping member 21 is not limited to that shown in the embodiment.

Further, the guide means G is not limited to that shown in the embodiment, and can be used for any workpiece P' other than the strut P.
When assembling to the attached member B' such as a car body, the 14th
As shown in Figure (a), while a retaining convex portion 70 is provided on the workpiece P', the engaging convex portion 70 is self-centered in the positioning hole /3' of the attached member B'. It is also possible to form a guide tapered surface 71 that leads to
) as shown in FIG. A guide clip T3 may be provided, and the design can be changed as appropriate. Further, in the above embodiments, the strut P is used as an example of the workpiece, but it is needless to say that the workpiece is not limited to this.

As explained above, the mechanical hand for an industrial robot according to the present invention includes a main body fixed to the robot, a clamp member provided on the main body for movably grasping a workpiece, and a clamp member for movable the workpiece. and a locking member for fixing the clamping member so as to restrain the workpiece, the action of the locking member effectively prevents the workpiece from wobbling and secures the gripping condition of the workpiece when the workpiece is transported. When attaching, it is possible to reliably guide a floating workpiece to the attachment part using a designated guide means without putting any load on the robot, and this effectively corrects deviations in the relative positional relationship between the workpiece and its attachment part. Can be absorbed.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram showing an example of a mechanical hand of a conventional industrial robot, Fig. 2 is a perspective view showing an example of a strut assembly process to which the present invention is applied, and Fig. 3 is an explanatory diagram showing an example of a mechanical hand of a conventional industrial robot. FIG. 4 is a partially cutaway front view of the mechanical hand, FIG. 5 is a partially cutaway right side view thereof, and FIG. 6 is a partially cutaway front view of the mechanical hand. Figure 7 is a perspective view showing an example of a strut temporary storage stand, Figure 8 is a sectional view showing the mechanical hand gripping the strut on the temporary storage stand, and Figure 9 is the positional relationship between the strut and the vehicle body before assembly. FIGS. 10 to 13 are cross-sectional views of main parts showing each strut assembly process, and FIG. 14 (a
) to (c) are sectional views showing modified examples of the guide means, respectively. B...Car body H...Mechanical hand G
... Guide means P ... Strut (work) R ... Robot 13 ... Positioning hole 15 ... Bolt insertion hole 16 ... Assembly bolt 20 ... Main body
21... Clamp member 22... Lock member 27.35... Spring 37... Movable arm 38... Floating mechanism 39...
・Abutment plate 43...Sleeve 44...Sliding body 47...Connecting body 49...Spring Patent applicant: Nissan Motor Co., Ltd. Representative Patent Attorney Kaoru Tsuchibashi Fig. 1 Fig. 10 Fig. 11 Fig. ＼2 Figure 12 Figure 13

Claims (1)

[Claims] 1) A main body that is fixed to the robot, a clamp member provided on the main body that grips a workpiece in a floating manner, and a lock that fixes the clamp member so as to restrain movement of the workpiece. A mechanical hand for an industrial robot, characterized by comprising: 2) The clamp member is comprised of a pair of movable arms that are provided on the main body so as to be openable and closable, and an abutment plate that is attached to opposing parts of the movable arms via a floating mechanism. A mechanical hand for an industrial robot according to claim 1. 3) The floating mechanism includes a sleeve that is pivotally supported by the movable arm, a sliding body that slides inside the sleeve, and a connecting body that has one end that is pivotally supported by the abutment plate and the other end that is connected to the sliding body. 3. The mechanical hand for an industrial robot according to claim 2, further comprising: a spring that urges the sliding body toward the contact plate. 4) The main body is configured to be expandable and contractible in a direction perpendicular to the mounting surface of the workpiece, and is provided with a biasing means for biasing the workpiece in the direction in which the main body extends. Mechanical components for industrial robots as described in Scope 1.