JP2003230964A - Positioning clamp device for work - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a positioning clamp device for a work in which a ground connection to the work by an earth clamp unit is disused, and at the same time, a material handling unit is made it possible to cope with the forms of a number of kinds of works. <P>SOLUTION: A plurality of the clamp units 1 to clamp the work W are installed to a material handling unit 201 of a material handling robot part 100 in a spot-welding system. Positioning pins 10 of each clamp unit 1 are respectively inserted into a plurality of reference holes H opened to the work W and the positioning of the work W to the material handling unit 201 is performed. While being in the positioned state, the peripheral clamping surface of the reference hole H of the work W is clamped by a clamping member 22 of a clamping mechanism 20 provided inside the positioning pin 10 of each clamp unit 1, and at the same time, a grounding function is provided to each clamping mechanism 20. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a work positioning clamp device for use in an automatic spot welding system adopting an indirect method for welding assembly parts (hereinafter abbreviated as works) of automobiles and the like.

[0002]

2. Description of the Related Art Recently, there has been an automatic spot welding system using a robot for spot-manufacturing automobiles, for example, for spot-welding mutually assembled works such as an outer panel and an inner panel made of thin metal plates constituting a door. In addition, in particular, for welding the hem part (welded part) after finishing the hemming process with the press mold of each panel of the door,
Indirect type spot welding means are preferably used.

FIG. 6 schematically shows an indirect type automatic spot welding system by a robot. This spot welding system is constructed by a material handling robot unit 100, a work hold unit 200, and a spot welding unit 300.

The material handling robot section 100 is composed of a robot body 101, a robot arm 102 extending from the robot body 101, and a power supply device 103 for supplying control power to the robot body 101. The robot main body 101 enables the robot arm 102 to move up and down and rotate using a vertical articulated manipulator. As a result, the work holding unit 200 attached to the tip of the robot arm 102
Tilting and rotation control of the
At 0, for example, as shown in FIG. 7, the workpiece W after the end of the hemming process between the outer panel w1 and the inner panel w2 of the automobile door W is grasped and carried. There is.

Further, the work holding unit 200 is a material handling unit 2 mounted on the tip of the robot arm 102.
01 and a plurality of clamp units 202 attached to the material handling unit 201.
On the other hand, the spot welded part 300 is the power supply unit 301.
And a rectifying transformer 302 connected to the power feeding unit 301, and a spot welding apparatus main body 303 connected to the rectifying transformer 302. The spot welding apparatus main body 303 includes a rectifying transformer 30.
The spot welding electric power is supplied from 2 and a spot electrode 305 which can be raised and lowered is installed on the mounting table 304 of the work W so as to face each other.

That is, the spot welding system described above is used in each clamp unit 20 of the material handling unit 201.
After grasping the work W at 2, the material handling unit 201
Is transferred to the earth electrode unit 307 detachably installed on the support 306 by the transfer control of the robot arm 102 of the robot body 101. Then, the earth terminal (not shown) of the material handling unit 201 is engaged with the earth electrode unit 307 to earth the work W, and the earth electrode unit 307 is detached while being engaged in the earth terminal to remove the material handling unit 201. Is conveyed to the spot welding apparatus body 303 together with the work W. Then, the hem portion of the work W is mounted and positioned on the mounting table 304 of the spot welding apparatus body 303.

In this state, the material handling unit 201 is lowered, and the tip end thereof is brought into contact with and pressed against the hem portion of the work W. Next, by supplying the spot welding power from the rectifying transformer 302 to the spot electrode 305, as shown in FIG.
A current is caused to flow between the spot electrode 305 and the hem on the inner panel side of the automobile door W as shown in FIG. This prevents welding traces from appearing on the hem on the outer panel side after spot welding.

That is, during spot welding, a current for spot welding is supplied from the rectifying transformer 302 to the spot electrode 305 of the spot welding apparatus body 303. This current flows from the positive side of the rectifying transformer 302 to the spot electrode 305 via the air cooling cable 308. Then, from the side of the spot electrode 305, it passes through the hem portion of the work W, passes through the ground electrode unit 307, and returns to the ground side of the rectification transformer 302 via the air cooling cable 309. During this period, a current is applied between the spot electrode 305 and the hem of the work W to perform spot welding on the hem of the work W.

Further, in such a spot welding system, as described above, the material handling unit 201 for holding the work W is provided with a plurality of clamp units 202 as a clamp device for holding and positioning the work.

By the way, for example, Japanese Patent Laid-Open No. 9-57457.
As disclosed in Japanese Patent Publication (hereinafter referred to as Prior Art 1), a conventional spot welding apparatus includes a material handling unit mounted on a robot arm and a clamping mechanism including a plurality of clamping units for gripping a workpiece. And an earth clamp mechanism including an earth clamp unit for earthing the work. Then, the work is held by the material handling unit by such a clamp mechanism, and the work is grounded at the time of spot welding by the ground clamp unit.

[0011]

However, in the spot welding apparatus of the prior art example 1 described above, for example, when welding is performed on the outer panel and the inner panel constituting the automobile door as the work, the material handling unit The clamp unit normally holds the outer peripheral edge portion which is the hem portion of the door.

However, such an automobile door has a front door, a rear door, and various outer shapes having different sizes depending on the vehicle type, and therefore, a dedicated material handling unit is required for each door or vehicle type. Become. As a result, it is impossible for a single material handling unit to support various types of workpieces. Therefore, the material handling units must be replaced one by one according to the type of workpieces, which improves workability and versatility. Inferior.

As a workpiece positioning and clamping device in the conventional spot welding system, a frame of the material handling unit 201 in the workpiece holding portion 200 of the robot arm 102 shown in FIG.
Further, as shown in FIG. 8, the work W is mounted on the material handling unit 20 by installing the three clamp units 30.
There is one having a structure in which three points are held in one.

A positioning pin 31 as a positioning member projects from each of the clamp units 30. These positioning pins 31 are inserted into the respective pin insertion holes H opened on the inner panel w2 side after finishing the hemming of the work, for example, the outer panel w1 and the inner panel w2 of the automobile door W as the material handling unit 201 descends. Is inserted. Each of these pin insertion holes H is
Corresponding to each positioning pin 31, by this, the work W is positioned with respect to the material handling unit 201 during work clamping. After positioning the work W by each of the clamp units 30 as described above, the work W is gripped.

On the other hand, the ground electrode is connected to the work W via the ground terminal 32 installed in the frame of the material handling unit 201. In this earth terminal 32, a slide frame 34 is provided on a support base 33 so as to be able to move up and down.
A ground electrode connection terminal 35 is provided. Further, on the side of the support base 33, the fixed rod 36 is provided with the ground electrode connecting terminal 3
5 is provided so as to be opposed thereto.

That is, in order to connect the work W to the ground, first, as shown in FIG. 6, the material handling unit 201 after gripping the work W is moved to the robot body 1 in the same manner as described above.
01 by the operation of the robot arm 102, the pillar 3
Earth electrode unit 307 detachably installed on 06
To the position. Then, the earth electrode unit 307 connected to the earth side of the rectifying transformer 302 via the air cooling cable 309 is inserted between the earth electrode connection terminal 35 of the earth terminal 32 and the fixed rod 36 (see FIGS. 7 and 8). After that, the slide frame 34 is lowered by driving the cylinder 37, and the earth electrode unit 307
Is carried and conveyed to the spot welding apparatus main body 303.

On the other hand, in the service hole SH opened in the work W, the earth clamp unit 40 is inserted and held together with the positioning and the clamp of the material handling unit 201 by each clamp unit 30. Also,
An earth cable 38 connected to the earth electrode connection terminal 35 of the earth terminal 32 is connected to the earth clamp unit 40, whereby the work W is earthed. Needless to say between the earth clamp unit 40 and the frame of the material handling unit 201, each clamp unit 30
Naturally, an insulator (not shown) is also interposed.

However, as described above, the automobile door W as such a work has various outer shapes having different sizes depending on the front door, the rear door, and the vehicle type. Moreover, the position and size of the service hole SH opened in the inner panel w2 also vary. For this reason, in the case where the earth clamp unit 40 having a site as a current collecting point is used in the opening of the service hole SH, a dedicated material handling unit 201 corresponding to each door form is required.

Therefore, in the prior art, the above-mentioned prior art 1 is used.
Similarly, it is impossible for one material handling unit 201 to handle various types of works. As a result, as in the conventional case, the material handling unit 201 must be replaced one by one according to the form of the work, and not only the workability and versatility are deteriorated, but also the work cost and the cost of the spot welding system as a whole increase.

Further, an example of a conventional concrete work positioning and clamping device is disclosed, for example, in Utility Model Registration No. 2594529 (hereinafter referred to as Prior Example 2), which was filed by the applicant of the present invention and registered earlier. There are things that can be. According to the second prior art, the material handling unit is composed of a plurality of clamp units. In each of these clamp units, a positioning pin having a cone-shaped tip as a positioning member is installed on a mounting board that is mounted on the frame of the material handling unit, and is clamped in a hollow portion formed in the inner axial direction of the positioning pin. The member is stored so that it can be rotated up and down. Then, when the work is clamped, the positioning pin is inserted into a reference hole which is opened in advance in the work made of a thin metal plate material to position the work.

Next, the clamp member housed inside the positioning pin is projected from a window opened to the tip end side of the positioning pin while tilting the clamp member toward the external clamp position (grasping surface) around the reference hole of the work as the clamp member moves up and down. It is rotated and displaced as described above. As a result, the tip gripping portion of the clamp member is brought into contact so as to grip the clamp position around the reference hole of the work, and the work can be positioned in the material handling unit and clamped.

In each of the clamp units in the positioning clamp apparatus described in the prior art example 2, when the reference hole is punched in the work and the work is clamped, the upright piece generated at the peripheral edge of the reference hole of the work is clamped. In order to avoid the above, the tip holding portion of the clamp member has an arch type, that is, a hook shape (key shape). As a result, the tip gripping portion of the clamp member grips the gripping surface of the workpiece so that the gripping surface of the workpiece straddles the standing piece at the peripheral edge of the opening of the reference hole of the work. There is no choice but to make local contact with the surface. Therefore, the gripping portion of the work may be distorted due to the local concentration of the gripping stress on the gripping surface of the work by the gripping portion of the tip of the clamp member. Naturally, the earth clamp unit 40 dedicated to earth as shown in FIGS. 7 and 8 is required, and the cost of the entire spot welding apparatus cannot be reduced.

The present invention has been made in view of the above circumstances, and by eliminating the ground connection to the work by the earth clamp unit, the material handling unit can be adapted to various work forms, work cost and spot An object of the present invention is to provide a work positioning clamp device that can reduce the cost of the entire welding system.

[0024]

In order to solve the above-mentioned problems, the present invention positions a work by means of positioning members which are respectively inserted into a plurality of pin insertion holes opened in the work, and in this positioning state. In a work positioning clamp device in a spot welding system equipped with a plurality of clamp units that grip the gripping surface at the peripheral edge of the pin insertion hole of the work with the clamp members of the clamp mechanism, the clamp mechanism of each clamp unit has a grounding function. It is characterized by having.

Further, the present invention is characterized in that, in the work positioning clamp device, each clamp unit is installed so as to have an array form positioned at a vertex of a polygon.

Further, according to the present invention, in the above-mentioned workpiece positioning clamp device, the clamp unit is a positioning member having a cone-like tip shape, and is housed in the hollow portion of the positioning member so as to be vertically movable, and the tip thereof. The gripping portion is provided with a clamp member for gripping the gripping surface of the peripheral edge portion of the pin insertion hole of the workpiece, and a drive means for moving the clamp member up and down. It is characterized in that it is rotatably displaced so as to project toward it, and that its distal end gripping portion has a jaw-like form capable of making substantially full contact with the gripping surface.

[0027]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to FIG.
2 to 3 will be described in detail with reference to the drawings shown in FIG. In addition,
In the illustrated embodiment according to the present invention, portions having the same configurations as those of the conventional spot welding system and material handling unit shown in FIGS. 6 to 8 will be described using the same reference numerals.

FIG. 1 is an enlarged perspective view of a clamp unit which constitutes a work positioning clamp device according to the present invention. FIG. 2 is an enlarged cross-sectional view schematically showing a gripping operation state of the clamp member built in the positioning member. Figure 3
FIG. 7 is an enlarged perspective view of a main part of a tip end portion of a positioning member in a grasping operation state of a clamp member.

As shown in FIG. 1, the work clamp unit 1 of the present invention comprises a mounting substrate 2 mounted on the frame of the material handling unit 201 and a guide 3 suspended from the mounting substrate 2. I have it. A slide table 4 having a positioning pin 10 on a lower end surface thereof is installed in the guide 3 so as to be vertically movable in the vertical direction X. Also, facing the other side surface 4b of the slide table 4, a first cylinder means 5 which is a damper means installed on the mounting substrate 2 is assembled. The first cylinder means 5 elastically urges the slide table 4 downward from the mounting substrate 2. Reference numeral 7 is a second cylinder means, which stops the sliding of the slide table 4 by moving the pressing member 6. The second cylinder means 7 is the mounting substrate 2
It is fixed to.

The slide table 4 has a knurled surface 4b, which is knurled over at least the moving range, on a side surface 4b facing the side surface 4a on the guide 3 side. A pedestal ring 8 for locking the work and a positioning pin 10 as a positioning member protruding from the pedestal ring 8 are attached to the lower end surface 4c.
A third cylinder means 25 used when rotating the holding clamp member 22 from the positioning pin 10 is provided between the a and the lower end surface 4c.

As shown in FIG. 2, the positioning pin 10 is
A slot 11 is formed in the inner axial direction,
It is installed on the lower end surface 4c of the slide table 4 with the tip 10a having the cone shape facing downward.
The positioning pin 10 has a slot 11 extending from the rear end to the vicinity of the tip.
A clamp mechanism 20 is stored inside. The clamp mechanism 20 includes a substantially V-shaped link member 21 rotatably supported by the slide table 4 and the link member 2.
Clamp member 2 connected to one arm of 1 through a pin
2, a cam-shaped guide groove 23 provided on the clamp member 22 for adding a rotary motion to the vertical movement of the clamp member 22, and a guide pin 24 for guiding the guide groove 23. The guide pin 24 penetrates the cam-shaped guide groove 23 and the slit 11 and slides on the slide table 4.
Is supported by.

The tip grip portion 22a of the clamp member 22 is
It has a jaw-like shape capable of making contact with the gripping surface of the work W almost entirely. The gripping surface of the work W is, as described later, a pin insertion hole (for example, a diameter of 20 mm) that is opened in advance in the inner panel w2 of the vehicle door W into which the positioning pin 10 is inserted when the work W is clamped. It refers to a portion where the outer periphery of H is formed as a flat surface within a diameter of 40 mm.

The other arm of the link member 21 is connected to the third cylinder means 25 attached to the slide table 4. Therefore, when the third cylinder means 25 is operated, the link member 2 moves in the direction of the solid arrow shown in FIG.
1 rotates, and the clamp member 22 rises. At this time, due to the action of the guide groove 23 and the guide pin 24, the clamp member 22 is tilted and rotated such that the tip end grip portion 22a thereof projects from the window 12 opened on the side surface of the positioning pin 10. Therefore, as shown by the chain double-dashed line in FIG. 2, the clamp member 22 is a peripheral portion of the pin insertion hole of the work W by the ring surface 8a of the pedestal ring 8 fixed to the outer peripheral portion on the tip end side of the positioning pin 10. It moves (displaces) to the position (clamp position) where it holds the holding surface. As a result, the workpiece interposed between the tip grip portion 22a of the clamp member 22 and the flat ring surface 8a of the pedestal ring 8,
For example, the inner panel w2 of the vehicle door W can be clamped, and the vehicle door W can be transported by the material handling unit 201 (see FIG. 1).

The first cylinder means 5 is a cylinder 5a serving as a main body, a piston rod 5b slidably fitted in the cylinder 5a, and housed in the cylinder 5a.
The cylinder 5a and the piston rod 5b are constituted by a return spring (not shown) which is always in elastic contact with each other to apply an urging force to the cylinder 5a and the piston rod 5b. The tip of 5b is attached to the slide table 4 via the bracket 9. The first cylinder means 5 also has a spring effect such that the grip surface of the work W is elastically pressed by the ring surface 8a of the pedestal ring 8 when the work W is gripped by the clamp mechanism 20 described later. .

The operation of the second cylinder means 7 causes the pressing member 6 to move the knurled surface 4 of the slide table 4.
It is used to press b and stop the movement of the slide table 4. The pressing member 6 is made of an elastic body having a high friction coefficient such as urethane or chloroprene as a stopper. The pressing member 6 is the knurled surface 4 in the initial state.
It stands by at a position separated from b, moves along the contact / separation direction Y by the operation of the second cylinder means 7, and stops the slide table 4 by the frictional force and biting force generated with the knurled surface 4b. .

Further, as shown in FIG. 1, the mounting substrate 2 and the slide table 4 are connected by a ground cable 28 via connection terminals 26, 27, which is not shown in the figure. A ground cable 38 from the ground terminal 32 of the material handling unit 201 is connected (see FIG. 6). As a result, the ground electrode is connected to the crank member 22 that constitutes the clamp mechanism 20 to provide the ground function.

Next, the clamping operation of the work W in this embodiment will be described mainly with reference to FIG. 1 and FIGS. 6 to 8. When clamping the work W, each of the above-mentioned clamp units 1
The material handling unit 201 is lowered by the operation of the robot arm 102 of the robot body 101.
Then, the tip end portion 10a of the positioning pin 10 of each clamp unit 1 is inserted into the pin insertion hole H of the work W as the material handling unit 201 descends. The descending operation of the material handling unit 201 is performed until the ring surface 8a of the pedestal ring 8 provided on the outer peripheral portion on the tip end side of the positioning pin 10 contacts the gripping surface of the work W. And FIG.
When the ring surface 8a comes into contact with the gripping surface at the peripheral edge of the pin insertion hole H as shown in FIG.
The pressing member 6 is used as the knurled surface 4 of the slide table 4.
It is pressed against b and the slide table 4 is fixed.

The contact state between the ring surface 8a and the gripping surface is confirmed by detecting the pressure of the air discharged from the air ejection port A of the ring surface 8a of the pedestal ring 8 shown in FIGS. ing. The air ejection port A is configured to eject air from an air path (not shown), and the air path is connected with a pressure sensor and a detection circuit that receives an output from the pressure sensor and monitors the internal pressure of the air path. Has been done. When the air ejection port A having a predetermined opening diameter, for example, a diameter of about 40 mm, is blocked by the contact between the ring surface 8a and the gripping surface, the output from the pressure sensor causes the detection circuit to increase the internal pressure of the air path. To detect. The control device of the material handling unit 201 stops lowering based on the detection result.

Next, after positioning the work W with respect to the material handling unit 201, the link member 21 is driven by the third cylinder means 25 to rotate in the direction of the solid line arrow shown in FIG. As the clamp member 22 moves upward, the clamp member 22 engages with the guide groove 23 and the guide pin 24, so that the work W
Of the pin insertion hole H is tilted and turned toward the gripping surface on the periphery of the pin insertion hole H. As a result, the tip gripping portion 22a of the clamp member 22 is rotationally displaced so as to project from the window 12 opened in the positioning pin 10, and grips the workpiece W interposed between the pedestal ring 8 and the ring surface 8a. Grasp the holding surface (clamping position) with almost all the surfaces in contact.

In the present invention, the positioning pins 10 of each of the above-mentioned three clamp units 1 are installed in the frame of the material handling unit 201 in an array form so as to present, for example, an equilateral triangle having a side of 450 mm. on the other hand,
The pin insertion holes H of the work W are also opened so as to match the arrangement form of each clamp unit 1 and the arrangement form of an equilateral triangle. As a result, the center of gravity of the positioning pins 10 of each clamp unit 1 and the pin insertion holes H of the workpiece W are matched with each other due to the shape of the arrangement, and the workpiece W can be clamped and conveyed in a stable and balanced manner.
Moreover, even if the size or shape of the work W differs depending on the front door, the rear door, and the vehicle type such as an automobile door, the pin insertion hole H having the same shape as described above is used regardless of the vehicle type. If it is opened, one material handling unit 201 can easily perform clamped conveyance of the work W having a different shape.

Here, since the panel surface of the inner panel w2 of the automobile door W has a complicated concavo-convex shape, the pin insertion holes H often have different heights. Therefore, even if the ring surface 8a of the pedestal ring 8 provided on the outer peripheral portion of the positioning pin 10 of one clamp unit 1 comes into contact with the gripping surface of the work W, the positioning pin 10 of another clamp unit 1 does not work. It may not come into contact with the gripping surface of W. In such a case, it is necessary to lower the material handling unit 201 until the positioning pins 10 of all the clamp units 1 come into contact with the gripping surface of the work W. At this time, the slide table 4 is fixed by the second cylinder means 7 for all the clamp units 1.
This is performed after it is detected that the positioning pin 10 of 1 comes into contact with the gripping surface of the work W. Therefore, the slide table 4 of the clamp unit 1 in which the positioning pin 10 is already in contact with the gripping surface moves against the urging force of the first cylinder means 5 as the material handling unit 201 descends, that is, the work piece. Mounting board 2 pressed by W
Move relatively to the side.

The pedestal ring 8 of the final positioning pin 10 is seated on the peripheral edge of the corresponding pin insertion hole H at the peripheral edge of the pin insertion hole H on which the pedestal ring 8 of the first positioning pin 10 is seated. Until then, since the biasing force of the first cylinder means 5 acts, when the peripheral edge is thin and the strength is low, the first cylinder means 5 is attached to the peripheral edge of the pin insertion hole H. Deflection corresponding to the urging force of occurs. The flexure may cause damage such as accidental scratches and wrinkles due to the pedestal ring 8 and the gripping portions 22a of the clamp members 22.

Energizing force (elastic force) of the first cylinder means 5
On the other hand, when the strength on the work W side is low, the positioning that directly uses the pin insertion hole H of the work W as described above is not performed, and the positioning clamp is performed in another step.
That is, the height of each positioning pin 10 is adjusted in advance,
By simultaneously inserting all the positioning pins 10 into all the positioning pin insertion holes H and completing the positioning, this kind of problem is solved. Of course, when each positioning pin 10 is inserted into each pin insertion hole H, each slide table 4 is locked by the extension of the second cylinder means 7. In this way, the first cylinder means 5
The urging force (elastic force) also reduces the force acting on the peripheral edge portion of each positioning pin 10, so that the peripheral edge portion of each pin insertion hole H is prevented from being bent and the pin insertion hole H caused by the bending is prevented. It is possible to prevent the occurrence of scratches and wrinkles on the peripheral portion.

Specifically, for adjusting the height of each positioning pin 10 with respect to each pin insertion hole H, the positioning table shown in FIG. 4 is used.
Use T. When adjusting the height of each positioning pin 10 of the material handling unit 201, all the clamp units 1
The second cylinder means 7 is contracted to unlock the slide table 4, and is moved to the maximum descending position by the urging force of the first cylinder means 5. Then, the robot arm 101 rotates the material handling unit 201 up, down, left and right, and front and back to move the specific positioning pin 10 above the positioning base T and push it down while facing the upper surface of the positioning base T. After the positioning pin 10 comes into contact with the positioning base T, the material handling unit 201 is further lowered by a predetermined length, and then the slide table 4 is fixed by the second cylinder means 7. Here, the predetermined length is a value converted from the position of the upper surface of the positioning table T and the height to the peripheral portion of the corresponding pin insertion hole H of the actual work W.

After this, the remaining two clamp units 1
Also adjust the position of. The positions of the remaining two positioning pins 10 are determined from the height of the workpiece W to the peripheral edge of the corresponding pin insertion hole H and the position of the positioning pin 10 that is initially positioned, and the slide table is set to that position. Four
Is controlled in the same manner as described above. Further, the positioning pin 10 may be positioned for each clamp unit 1 without using the height position of the positioning pin 10 obtained by positioning one positioning pin 10 as a reference. By thus adjusting the position of each positioning pin 10 in advance, even if the strength of the work W is low and the strength of the pin insertion hole H is low, the positioning clamp device according to the present embodiment is used. The workpiece W can be positioned and clamped.

Furthermore, the height position of the positioning pin 10 adjusted as described above can be confirmed by the position confirmation device 50 having a simple structure shown in FIG. As shown in the figure, the position confirmation device 50 is installed on the side of the positioning table T, and the robot arm 102
After the positioning is completed by lowering (FIG. 6), a check bar 51 for confirming the position in the height direction is provided so as to be able to move up and down while bringing the tip end surface of the positioning pin 10 into contact with it. The check bar 51 has a return spring 52.
By this, it is always pushed back upward. When confirming the position, a predetermined stroke a is calculated from the lowering stroke of the positioning pin 10 with respect to the workpiece W determined by the robot arm 102 and the positioning table 50.
The movement of the robot arm 102 is temporarily stopped by a short stroke, and then the robot arm 102 is stopped again at a position where the predetermined stroke b is added to the predetermined stroke a, and the first stage check is performed at the first stop position. The second stage check is performed at the next stop position. In this case, when the position of the positioning pin 15 is correctly set by the robot arm 2 and the positioning table 50 when confirming the position, the proximity sensor 53 checks the above-mentioned first-step check position. The lower end of the check bar 51 is the proximity sensor 53.
Above the sensing range above the proximity sensor 53 by a predetermined distance (same distance as the predetermined stroke a) a above, and at the check position of the second stage, the lower surface of the check bar 51 is above the sensing range above the proximity sensor 53. It is arranged so as to exist below by a predetermined distance (the same distance as the predetermined stroke b) b.

When the proximity sensor 53 is arranged in this way and the lowering operation of the robot arm 102 at the time of position confirmation is divided into two stages and the position of the positioning pin 10 is confirmed, the first stage and the second stage are checked. Proximity sensor 53 ON, O
The FF signal can be used to determine if the positioning was proper. That is, when the proximity sensor 53 outputs an ON signal in the first-stage check, the positioning pin 1 by the robot arm 102 and the positioning base T is moved.
It is possible to detect that the height position of 0 is set to the plus side (too much) and the setting is defective, and when the OFF signal is output (when the ON signal is not output), In the one-step check, it can be presumed that the setting was proper. Then, the authenticity is confirmed in the second check stage. In other words, even if the OFF signal is output from the proximity sensor 53 in the first-stage check, this state is detected by the proximity sensor 53 from the check bar 51.
It is not possible to distinguish whether the lower end of the robot is too far away, but when the OFF signal is output from the proximity sensor 53 in this second stage check, the positioning pin by the robot arm 2 and the positioning base T is positioned. The height position of 10 is set to the minus (too much) side,
It is possible to determine that the setting was bad,
Furthermore, it is turned off at the first stage check and turned on at the second stage.
When the signal is output from the proximity sensor 53, it is possible to determine that the setting in the height direction for the positioning pin 10 is correct. As described above, according to the position confirmation device 50, the position confirmation of the positioning pin 10 can be detected by the single proximity switch 53, which contributes to cost reduction.

According to the workpiece positioning clamp device of the present invention, the workpiece W is positioned without using the service hole SH opened in the workpiece W such as an automobile door as a gripping portion of the clamp unit dedicated to grounding. The plurality of clamp units 1 for gripping the work W also function as the earth clamp unit by utilizing the pin insertion holes H for the. As a result, unlike the conventional case, it is not necessary to use the clamp unit 40 dedicated to grounding (see FIGS. 7 and 8), and thus the cost of the entire apparatus can be reduced. Moreover, when the workpiece is clamped, the material handling unit 20
Since the work W can be positioned with respect to 1 and clamped, as well as grounded, the work cost can be reduced. Further, when the work W is grounded, each clamp unit 1 also serves as a ground clamp unit. As a result, there are a plurality of current collection points, and the current density flowing in each clamp position of each clamp unit 1 can be reduced, so that local current collection of current as in the past is prevented.

Further, since the tip end gripping portion 22a of the clamp member 22 which constitutes the clamp mechanism 20 has a jaw-like shape capable of substantially contacting the gripping surface of the work W, it is as usual when clamping. The current density on the gripping surface of the workpiece W does not increase. This prevents the generation of heat at the gripping portion of the work W during spot welding.

Moreover, the concentration of the local gripping stress by the tip gripping portion 22a of the clamp member 22 with respect to the gripping surface of the work is prevented, so that the gripping portion of the work W is not distorted and deformed. Therefore, the quality of the work after releasing the clamp after the spot welding as in the past is not caused.

Further, since the plurality of clamp units 1 are arranged so that they are arranged at the vertices of a polygon such as an equilateral triangle, when spot-welding a work W such as an automobile door, an opening is made for each vehicle type. If the pin insertion holes H of the work W to be made are also arranged in the same shape, it becomes possible to clamp the work W of all vehicle types by one material handling unit 201. As a result, it is not necessary to replace the material handling unit 201 according to each vehicle type as in the past, and workability can be improved.

In the above-described embodiment of the present invention, the three clamp units 1 are used to form an equilateral triangle arrangement, but the present invention is not limited to this. For example, an isosceles triangle or other triangle, or 3
A plurality of clamp units 1 may be used to form a polygonal array.

Further, a pin insertion hole H opened on the side of the work W
It is preferable that the center of gravity of the shape of the array form is matched with the center of gravity of the work W itself. As a result, the balance of the work W gripped by the material handling unit 201 via each clamp unit 1 becomes more stable when the work clamp is transported.

In addition, it goes without saying that the present invention can be variously modified and implemented without departing from the scope of the present invention.

[0055]

As described above, according to the workpiece positioning and clamping apparatus of the present invention, the following excellent effects can be obtained.

According to the present invention, the work is positioned by the positioning members which are respectively inserted into the plurality of pin insertion holes opened in the work, and in this positioning state, the gripping surface of the peripheral portion of the pin insertion hole of the work is clamped. It is not necessary to use a grounding clamp unit dedicated to grounding because the clamping mechanism of the plurality of clamp units to be gripped with is provided with a grounding function. As a result, the cost of the entire apparatus can be reduced, and at the time of clamping the work, the work can be positioned with respect to the material handling unit and the ground connection can be performed together with the clamp, so that the work cost can also be reduced. Moreover, since each clamp unit also serves as the earth clamp unit, the ground connection portions are dispersed into a plurality of portions, and the electric current is not locally collected at a specific portion of the work.

Further, according to the present invention, since each clamp unit is installed so as to have an array form located at the apex of a polygon, when workpieces such as automobile doors are spot-welded, openings are made for each vehicle type. By arranging the reference holes of the workpieces to be arranged in the same shape, one material handling unit can clamp the front door, the rear door, and even workpieces of all vehicle types. As a result, it is not necessary to replace the material handling unit according to the form of each work, and workability can be improved.

Further, according to the present invention, the upper and lowering operations of the clamp member in which the clamp unit is housed in the hollow portion of the positioning member inserted into the pin insertion hole of the work in such a manner that the clamp unit can be moved up and down, and the tip grasping portion is pinned to the work pin. Since the distal end gripping portion of the clamp member is formed into a jaw-like shape so that it can substantially contact the gripping surface while being pivotally displaced so as to project toward the gripping surface at the peripheral edge portion of the insertion hole, the clamp At times, the current density on the gripping surface of the work does not increase. This allows
At the time of spot welding, it is possible to prevent the generation of heat at the gripping portion of the work.

Moreover, it is possible to prevent local concentration of the gripping stress by the tip gripping portion of the clamp member with respect to the gripping surface of the work, so that the gripping portion of the work is not distorted and deformed. Therefore, the quality of the work after the clamp is released after the spot welding is not caused.

[Brief description of drawings]

FIG. 1 is an enlarged perspective view showing an embodiment of a clamp unit constituting a work positioning clamp device according to the present invention.

FIG. 2 is an enlarged cross-sectional view schematically showing a grasping operation state of a clamp member built in a positioning member.

FIG. 3 is an enlarged perspective view of a main part of a positioning member on a tip end side.

FIG. 4 is a diagram showing a material handling unit and a positioning base in the embodiment of the present invention.

FIG. 5 is an explanatory diagram showing the configuration of a position confirmation device for confirming the adjustment of the height position of a positioning pin.

FIG. 6 is an explanatory diagram showing a schematic configuration of an indirect automatic spot welding system by a conventional robot.

FIG. 7 is a side view schematically showing an overall configuration of a material handling unit in which a conventional workpiece positioning clamp device is installed.

FIG. 8 is an exploded perspective view showing an arrangement state and an insertion state with respect to a reference hole of a work in each positioning member of the material handling unit.

[Explanation of symbols]

1 ... Clamp unit 10-positioning pin 10a ... Tip 11 …… Slot 20 ... Clamp mechanism 21 ... Link member 22 ... Clamping member 22a ... Tip gripping part 23 ... Guide groove 24 …… Guide pin 25 ... Third cylinder means 26: Connection terminal 27 ... Connection terminal 28-earth cable 32 ... Earth terminal 35: Ground electrode connection terminal 36: Fixed rod 38: Ground cable 100 ... Material handling robot 101 ... Robot body 102 ... robot arm 201 …… Material handling unit 300 …… Spot weld 303 ...... Spot welding equipment main body 307 ... Ground electrode unit A: Air ejection hole H: Pin insertion hole W: Work (automobile door) w1 ... work (outer panel) w2 …… Work (inner panel) X: Vertical direction Y: Direction of contact

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Toshio Kume             1907 Hirata Town, Suzuka City, Mie Prefecture Honda Motor Co., Ltd.             Suzuka Works Co., Ltd. (72) Inventor Makoto Yamazaki             1907 Hirata Town, Suzuka City, Mie Prefecture Honda Motor Co., Ltd.             Suzuka Works Co., Ltd. (72) Inventor Koji Nishikawa             1907 Hirata Town, Suzuka City, Mie Prefecture Honda Motor Co., Ltd.             Suzuka Works Co., Ltd. (72) Inventor Hideki Ishikawa             4-16 Gotoyama, Azai, Ama prefecture             Kojima Koki Co., Ltd. F-term (reference) 3C007 AS11 BT19 DS02 ES02 ET02                       EU07 EV05 EV23 EW00 HS12                       KS03 KV15 KX07                 4E065 CA08

Claims (3)

[Claims] 1. A positioning mechanism, which is inserted into each of a plurality of pin insertion holes opened in a work, positions the work, and in this positioning state, a clamping mechanism is provided on a gripping surface of a peripheral portion of the pin insertion hole of the work. Positioning clamp device for a workpiece in a spot welding system including a plurality of clamp units gripped by the clamp member, wherein the clamping mechanism of each of the clamp units has a grounding function. apparatus. 2. The workpiece positioning clamp device according to claim 1, wherein each of the clamp units is installed so as to have an array form positioned at a vertex of a polygon. 3. The clamp unit includes a positioning member having a cone-like tip shape, and is rotatably housed in a hollow portion of the positioning member so as to be vertically rotatable. A clamp member for gripping the gripping surface at the peripheral edge portion and a driving means for raising and lowering the clamp member are provided, and the clamp member is pivotally displaced so as to be able to project toward the gripping surface with the lifting operation by the driving means. The workpiece positioning clamp device according to claim 1 or 2, wherein the tip gripping portion has a jaw-like shape capable of substantially contacting the gripping surface.