JPH05329717A - Work carrying device - Google Patents

Abstract

PURPOSE:To correctly insertedly fit a work in a work insert-fitting fitting hole even in the case where the work insert-fitting hole deviates from a work insert-fitting position, and some error exists in the teaching data of a robot. CONSTITUTION:A shock absorbing mechanism 15 is provided between the wrist shaft 14 of a robot and its grasping tool 16, and a discrepancy between the axis of the shaft part 40a of a bevel gear 40 and the axis of the work insert- fitting hole of a jig is compensated by the mechanical shift action of the shock absorbing mechanism 15. In addition, in the case where the discrepancy having such a size as the shock absorbing mechanism 15 can not compensate occurs, the discrepancy is compensated by the shift processing made by a robot controller of the shaft part 40a.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a work transfer device for transferring a work and inserting the work into a hole provided at a preset position.

[0002]

2. Description of the Related Art In a conventional work transfer apparatus of this type, a robot is used as a transfer means and a movement path of a work up to a work insertion hole provided in a jig or the like is taught to the robot in advance. Then, the work is inserted into the insertion hole by controlling the positioning of the robot based on the teaching data.

[0003]

By the way, when the work insertion hole is fixedly installed, the work should be properly inserted into the work insertion hole unless the teaching data is incorrect. You can

However, when the position of the work insertion hole changes or when there is an error in the teaching data, the position of the work does not match the position of the work insertion hole, and the work is not moved. It cannot be inserted into the work insertion hole.

It is an object of the present invention to properly place a work in the work insertion hole even when the work insertion hole is deviated from the work insertion position or when there is some error in the teaching data of the robot. It is an object of the present invention to provide a work transfer device that can be inserted into and attached to.

[0006]

SUMMARY OF THE INVENTION The present invention is a work transfer device for transferring a work and inserting the work into a hole provided at a preset position, the work holding device including a work holding device and a support for supporting the work holding device. Between the robot and the elastic buffering means which gives the gripping means a degree of freedom of movement of a predetermined width in the direction orthogonal to the axis of the hole, and the shaft of the work is not inserted into the hole. If the insertion error detecting means for detecting this and the work gripped by the work gripping means, the robot is controlled so as to be moved to the position of the hole along the axis of the hole, and When the insertion error detection means detects an insertion error, the procedure for retracting the gripping means to separate the workpiece from the hole, and a preset distance of the gripping means in a direction orthogonal to the axis of the hole Shift procedure and above The gripping means is advanced is characterized by and a robot control unit to execute the above robot work reinsert operation consisting of steps of moving the workpiece to the position of said holes.

[0007]

When the relative positional deviation amount between the hole and the work is within the movable width of the gripping means, the gripping means is moved in the direction for correcting the positional deviation and the work is inserted into the hole. To be done. When the amount of deviation is larger than the movable width, the insertion error detection means detects an insertion error, and as a result, the work re-insertion operation including the above procedure is performed.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. The embodiment shown in FIG. 1 includes a work transfer robot 10 and a robot controller 20 that controls the robot 10, and is used to transfer a bevel gear 40 that is a work to a shot peening machine 30.

The robot 10 is of a so-called SCARA type, and the first arm 1 supported on the turning shaft 11 is provided.
2, a second arm 13 pivotally supported by the tip of the first arm 12, a wrist shaft 14 movably supported by the tip of the second arm 13, and a tip of the wrist shaft 14. Work gripping tool 16 attached via a cushioning mechanism 15 described later.
(Chuck).

As shown in FIG. 3A, the buffer mechanism 15 includes circular plates 151 and 152 which are parallel to each other.
The plate 151 is composed of a pin 153 penetrating the central portion of the plate 151, 152 and a rubber column 154 interposed between the plate 151, 152.
Is connected to the tip of the wrist shaft 14 and the plate 152 is connected to the base end of the gripper 10.

Pin hole 1 formed in the plate 151
The diameter of 51a is set larger than the diameter of the pin 153. And, at all times, the rubber pillar 154
The supporting force of the pin 1 causes the pin 1 to move to the center of the pin hole 151a.
53 is located.

In this embodiment, the diameter of the pin hole 151a is set so that a space L of about 2 mm is formed between the outer peripheral surface of the pin 153 and the inner peripheral surface of the pin hole 151a. There is.

On the other hand, as shown in FIG. 3 (b) which is a plan view of the cushioning mechanism 15, three rubber pillars 154 are arranged around the pin 153 with an angular interval of 120 degrees. ing.

According to the buffer mechanism 15 having the above structure, the elasticity of the rubber columnar body 154 is utilized to make the plates 151, 1
52 can be relatively translated by the distance L.

The shot peening machine 30 shown in FIG.
The circular rotary table 31 shown in FIG.
And a shot peening mechanism section 32 in which one half of the number 1 is stored. A plurality of (for example, 20) jigs 33 having holes 33a for inserting the shaft portion 40a of the bevel gear 40 on the upper portion of the rotary table 31 are projected at equal intervals. There is.

A lifter 50 is provided on the side of the robot 10.
And the bevel gear 40 supplied to the shot peening machine 30 is placed in a work pallet 51 arranged on the lifter 50. When the robot 10 grips the bevel gear 40, the work pallet 51 is lifted by the lifter 50 to a predetermined work take-out height.

FIG. 4 exemplifies the procedure executed by the robot controller 20, and the operation of this embodiment will be described below with reference to the figure.

In this procedure, first, the robot arm 12,
13 to position the gripping tool 16 directly above the pallet 51 (step 100), and then retract the wrist driving cylinder 18 attached to the arm 13 to retract the gripping tool 16
And the bevel gear 40 in the pallet 51 is gripped by the gripping tool 16 (step 101).

Next, the gripping tool 16 is positioned on the jig 33 in front of the front of the robot 10 (step 102). Then, the shaft portion 40a of the bevel gear 40 is attached to the hole 33a of the jig 33.
The gripping tool 16 is moved down so as to move to a position where it can be inserted into (step 1).
03).

The robot controller 20 detects whether or not the gripping tool 16 has descended to the target position based on the output of a stroke sensor (not shown) attached to the cylinder 18 (step 104). If the result of the determination is YES, that is, if the shaft portion 40a of the bevel gear 40 is inserted into the hole 33a of the jig 33, the holding tool 16 is opened (step 105), and then the holding tool 16 is opened. The robot 10 is controlled so that 16 is returned to a predetermined standby position (step 106). The above procedure is executed based on the data taught in advance.

By the way, the above shot peening machine 3
In the case of 0, the jigs 33 are sequentially positioned at the work insertion position P by rotating the rotary table 31, but the positioning accuracy is not so good, and the above-mentioned fixing is usually performed with a positioning error of about 5 mm. The tool 33 is positioned. On the other hand, there is a possibility that the teaching data may be erroneous due to a mistake in the teaching operation or a positioning error of the jig 33.

Therefore, when inserting the bevel gear 40, the axis of the hole 33a of the jig 33 and the shaft portion 40a of the bevel gear 40 are inserted.
There is often a deviation from the axis of. However, when the deviation is less than a certain value, the shaft portion 40a can be properly inserted into the hole 33a by the deviation correcting action of the buffer mechanism 15.

That is, as shown in FIG. 5, the opening edge portion of the hole 33a of the jig 33 and the shaft portion 40a of the bevel gear 40.
The peripheral surface of the front end portion of each has tapered surfaces 33b and 40b formed by chamfering. Therefore, for example, as shown in FIG.
Assuming that the shaft 3 is slightly displaced to the right by an amount {circle around (3)}, the taper surface 33b based on the pressing force of the shaft 40 is formed.
The shaft portion 40 is urged to the left by the guiding action of and 40b.

Since the urging force is transmitted to the plate 152 of the buffer mechanism 15 shown in FIG. 3 via the grasping tool 16 of the robot 10, the plate 152 is forcibly moved leftward with respect to the plate 151. As a result, the shaft portion 40a is inserted into the hole 33a while being guided by the hole 33a. In this way, when the displacement amount of the shaft portion 40a is small, the shaft portion 40a can be inserted into the hole 33a by the displacement correcting action of the buffer mechanism 15.

The possible relative parallel movement amount L of the plates 151 and 152 in the buffer mechanism 15 is determined by the width of the tapered surfaces 33b and 40b.
Is set to a value equal to or more than the maximum movable amount in the lateral direction (2 mm in this embodiment). The plate 152 of the buffer mechanism 15 is slid in the direction opposite to the displacement direction regardless of the displacement direction of the shaft portion 40a.

Next, a case will be described in which the amount of displacement of the axis of the shaft portion 40a relative to the axis of the hole 33a is considerably large.

In this case, as shown in FIG. 6A, since the lower surface of the shaft portion 40a abuts on the upper surface of the jig 33, the lowering operation of the gripping tool 16 is stopped. The determination result in step 104 is NO. That is,
In step 104, the insertion error of the shaft portion 40a is detected. Therefore, the controller 20 executes the procedure in step 10.
6, the gripper 16 is raised until the lower surface of the shaft 40a is a preset distance from the upper surface of the jig 33, as shown in FIG. 6B.

When the ascending process of step 107 is completed, the gripping tool 16 is shifted rightward by a predetermined distance α so that the shaft portion 40a is moved to the position shown by the broken line (step 108), and then, The gripping tool 16 is lowered to move the shaft portion 40a to the target insertion position (step 109). In addition, in this embodiment, the shift amount α of the gripping tool 16 is set to 4 mm.

At the next step 110, it is judged whether or not the gripping tool 16 has been lowered to the target insertion position.
The right shift operation of the gripping tool 16 further increases the amount of displacement of the axis of the shaft portion 40a with respect to the axis of the hole 33a, so the determination result of step 110 is naturally NO.

Then, again, the gripping tool 16 is raised to the position shown by the broken line in FIG. 6B (step 11
1) Then, the gripping tool 16 is shifted leftward so that the shaft portion 40a is moved to the position shown by the broken line in FIG. 6C (step 1112). In this case, the leftward shift amount of the gripping tool 16 is 2α, but when the shaft portion 40a in the original position shown by the solid line is used as a reference, α
Is.

When the shift process is completed, the shaft portion 4
In order to move 0a to the target insertion position, the grip 16 is lowered (step 113), and then it is determined whether the grip 16 is lowered to the target insertion position (step 114).

The left shift operation of the gripping tool 16 is performed by using the hole 33.
The amount of deviation of the axis of the shaft 40a with respect to the axis of a is reduced below the amount of misregistration that can be corrected by the buffer mechanism 15 (in this example, the amount of deviation is zero). The procedure is transferred to step 105.

If the displacement of the shaft 40a with respect to the hole 33a becomes abnormally large for some reason and the result of the determination in step 114 is NO, an alarm is issued by a buzzer and the like. The gripping tool 16 is returned to the standby position (step 115). If the result of the determination in step 110 is YES, the procedure moves to step 105.

Thus, according to this embodiment, the hole 3
When the displacement amount of the shaft portion 40a with respect to 3a is 2 mm or less, the shaft portion 40a can be inserted into the hole 33a by the displacement correcting action of the buffer mechanism 15, and if the displacement amount is within 6 mm. , Steps 107 to 11 above
0 or the processing shown in 111 to 114
It is possible to insert 0a. It should be noted that the deviation amount of 6 mm or more is usually impossible as long as the robot 109 and the rotary table 31 are normally operating.

The bevel gear 40 inserted into the hole 33a of the jig 33 is carried into the shot peening mechanism 32 by the rotation of the rotary table 31, and is subjected to the shot peening process there. Then, the bevel gear 40 that has completed the shot peening process is the rotary table 3
It is returned to the position P again by the rotation of 1, and then
The work pallet 52 on the lifter 50 by the robot 10
It is transported inside.

When the bevel gear 40 that has undergone the shot peening process is removed from the hole 33a of the jig 33, a slight deviation may occur between the position of the gripping tool and the position of the shaft portion 40a of the bevel gear 40. The buffer mechanism 15 has a function of correcting the deviation in this case as well. Therefore, the extracting process is executed very smoothly.

In the case of the above-mentioned embodiment, since the direction of the positioning error of the jig 33 is the horizontal direction in FIG. 2, the shaft portion 40a is re-shifted to the left and right while it is repositioned. Although the insertion / removal processing is executed, if the direction of occurrence of the positioning error is front / rear / left / right, the re-reinsertion processing according to the above may be executed in the front / rear direction as well.

In the above embodiment, the cushioning mechanism 15 using the columnar rubber 154 is used.
Instead of 5, the buffer mechanism 17 shown in FIG. 7 may be used.

The cushioning mechanism 17 includes movable members 171 and 172 which are orthogonal to each other, supports 173 and 174 which respectively house them, and pins 175 which penetrate the movable members 171, 172 and the central portions of the supports 173 and 174. It has and.

As shown in FIG. 8B, the supports 173 and 174 have concave grooves 173a and 174a for guiding the movable members 171 and 172 in the X and Y directions in FIG. 7, respectively. Then, the groove 17
Between both end walls of 3a and both ends of the movable member 171, and between both end walls of the groove 174a and both ends of the movable member 171,
Each spring 176 is interposed.

As shown in FIG. 8A, the support 17
The pin fitting hole 173b of No. 3 is a long hole along the X direction, and as shown in FIG. 7C, the pin fitting hole 174b of the support 174 is a long hole along the Y direction. Therefore, the support body 174 has a pin fitting hole 173 with respect to the support body 173.
b and 174b have a degree of freedom of movement in the X and Y directions defined by the major axis lengths, and therefore, this cushioning mechanism 17 is shown in FIG.
If it is interposed between the wrist shaft 14 and the gripping tool 174 shown in (1), the same displacement correction action as that of the buffer mechanism 15 can be obtained.

Although the above embodiment is applied to the transfer of the work to the shot peening machine 30, it can be applied to any machine that requires the work to be inserted into a hole at a predetermined position.

[0043]

According to the present invention, even when the work insertion hole is deviated from the work insertion position or when there is some error in the teaching data, the work is properly inserted into the work insertion hole. Therefore, it is possible to improve the efficiency of the work insertion work and enhance the productivity.

[Brief description of drawings]

FIG. 1 is a side view conceptually showing an embodiment of the present invention.

FIG. 2 is a plan view of the embodiment.

3A and 3B are a partially cutaway side view and a plan view of a cushioning mechanism, respectively.

FIG. 4 is a flowchart showing an example of a work insertion procedure executed by the robot controller.

FIG. 5 is a conceptual diagram exemplifying a manner of inserting and mounting a work when the displacement can be corrected by a buffer mechanism.

FIGS. 6A, 6B, and 6C are conceptual views exemplifying a manner of inserting and mounting a work in a case where the displacement correction by the cushioning mechanism cannot be performed.

FIG. 7 is a perspective view conceptually showing another example of the buffer mechanism.

8 (a), (b) and (c) are respectively FIG.
The top view of the buffer mechanism shown in FIG.

[Explanation of symbols]

 10 robot 12,13 arm 14 wrist shaft 15,17 buffer mechanism 16 gripping tool 20 robot controller 30 shot peening machine 31 rotary table 32 shot peening mechanism part 33 jig 33a work insertion hole 40 bevel gear 40a shaft part 50 lifter

Claims (1)

[Claims] 1. A work transfer device for transferring a work and inserting the work into a hole provided at a preset position, wherein the work holding device is provided between the work holding device and a support body supporting the work holding device. On the other hand, a robot interposing an elastic buffering means that gives a predetermined degree of freedom of movement in a direction orthogonal to the axis of the hole, and an insertion part that detects this when the shaft part of the work is not inserted in the hole. The attachment error detection means and the work gripped by the work gripping means control the robot so that the work is conveyed to the position of the hole along the axis of the hole, and the insertion error detection means When an insertion error is detected, the gripping means is retracted to separate the work from the hole, the gripping means is shifted by a preset distance in a direction orthogonal to the axis of the hole, and the gripping means. To move forward A work transfer device, comprising: a robot control unit that causes the robot to execute a work reinsertion operation including a procedure for moving the work to the position of the hole.