JP2015098050A - Resistance welding apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a resistance welding apparatus which is capable of spot welding by disposing a chip for spot welding on a rotary electrode fixed to a pair of electrode holders.SOLUTION: A resistance welding apparatus 10 includes: first and second electrode holders 16 and 17 being a pair disposed on first and second support mechanisms 14 and 15; first and second rotary electrodes 18 and 19 that are detachably mounted on the first and second electrode holders 16 and 17 respectively; first and second rotation drive means 22 and 23 that rotatably drive the first and second electrode holders 16 and 17 respectively; pressurizing means 25 that relatively moves the first and second support mechanisms 14 and 15 to conduct approaching movement and pressurization, and separating movement of the first and second rotary electrodes 18 and 19 being a pair; and electric power supply means 26 that supplies electric power to the first and second rotary electrodes 18 and 19. In the resistance welding apparatus 10, first and second chips 71 and 72 for spot welding are provided that are capable of spot welding, on the first and second rotary electrodes 18 and 19.

Description

The present invention relates to a resistance welding apparatus used when joining metal materials, and more particularly to a resistance welding apparatus capable of seam welding and spot welding by changing electrodes.

It is well known, for example, as described in Patent Document 1, that a material to be welded (usually a steel plate) is inserted between a pair of disk-shaped electrodes (rotating electrodes) to perform seam welding.
In addition, as described in Patent Document 2, it is well known that a seam welder is mounted on an arm of a robot driven by a motor.

In the conventional technique, the disc-shaped electrode is exchangeably attached to the electrode holder with a screw arranged in an annular shape, the disc-shaped electrode to be paired is water-cooled, and the disc-shaped to be rotationally driven is a disc-shaped It is well known that power is supplied to the electrodes via brushes and slip rings.

Japanese Patent Laid-Open No. 2002-346761 JP 2013-59777 A

However, in the prior art, the disc-shaped electrode is dedicated to seam welding, and spot welding is not impossible. However, spot welding causes local consumption of the electrode, and then seam welding is performed. Since it cannot be used as an electrode, there was a problem that it was not preferable.
Another problem is that the disk-shaped electrode is attached to the electrode holder via a screw, so that it is troublesome to mount and remove the disk-shaped electrode.

The present invention has been made in view of such circumstances. The first object of the present invention is to enable spot welding by providing a spot welding tip on a rotating electrode fixed to a pair of electrode holders. Provided is a resistance welding apparatus whose second object is that replacement can be performed relatively easily.

According to a first aspect of the present invention, there is provided a resistance welding apparatus according to a first invention, wherein a pair of first and second electrode holders provided in the first and second support mechanisms respectively, and the first and second electrode holders. The first and second rotating electrodes, which are detachably mounted on the electrode holders, respectively, and the first and second electrode holders, which are attached to the first and second support mechanisms, respectively, are rotated. The first and second rotation driving means to be driven and the first and second support mechanisms are moved relative to each other, so that the first and second rotating electrodes that are paired move in close proximity and pressurize and move away from each other. In a resistance welding apparatus comprising a pressurizing means for performing power and a power supply means for supplying power to the first and second rotating electrodes,
The first and second rotary electrodes are provided with first and second spot welding tips capable of spot welding with the first and second rotary electrodes facing each other at a specific angular position.

Furthermore, the resistance welding apparatus according to the second invention in accordance with the second object is the resistance welding apparatus according to the first invention, wherein the first and second rotating electrodes are aligned with their respective axes and are non-circular. A notch is provided, and the first and second rotating electrodes can be removed from the first and second electrode holders by being inserted into the non-circular notch at a specific angular position, and the first and second electrodes can be removed at other angles. First and second clamp members that press and fix the second rotating electrode against the first and second electrode holders respectively, and first and second clamp members that advance and retract the first and second clamp members, respectively. The first and second support mechanisms have advance / retreat means. Here, the non-circular notch means a non-circular shape (rectangular shape, star shape, rectangular shape, a star shape having a plurality of projecting pieces (arm members) radially at an equal angle, a trifurcated shape, etc.) when viewed from the front. Say.

A resistance welding apparatus according to a third invention is the resistance welding apparatus according to the second invention, wherein the first and second advancing / retreating means each have a spring and a cylinder, and are urged by the spring. The first and second rotating electrodes are always pressed against the first and second electrode holders by the first and second clamp members, and the cylinder is driven to oppose the spring to the first and second electrodes. The clamp member is separated from the first and second rotating electrodes.
A resistance welding apparatus according to a fourth invention is the resistance welding apparatus according to the third invention, wherein an air cylinder is used as the cylinder, and the compressed air from the air source is further increased by a pressure intensifier. This makes it possible to reduce the size of the apparatus.

A resistance welding apparatus according to a fifth invention is the resistance welding apparatus according to the second to fourth inventions, wherein the first and second rotating electrodes are the first and second clamping members are the first and second clamping members. When the second rotating electrode is pressed against the first and second electrode holders, there is a positioning recess into which the first and second clamp members are fitted.

A resistance welding apparatus according to a sixth invention is the resistance welding apparatus according to the second to fifth inventions, wherein the first and second rotating electrodes are sandwiched separately from the first and second support mechanisms. Thus, there is provided an electrode transport mechanism that rotates by a predetermined angle and removes and attaches the first and second rotating electrodes that are not fixed by the first and second clamp members.

A resistance welding apparatus according to a seventh aspect of the invention is the resistance welding apparatus according to the first to sixth aspects of the invention, wherein the first and second rotation driving means are servo motors with a reduction gear.

The resistance welding apparatus according to an eighth invention is the resistance welding apparatus according to the first to seventh inventions, wherein any one or both of the first and second rotating electrodes are a single or a plurality of the first, A second spot welding tip is provided.

A resistance welding apparatus according to a ninth invention is the resistance welding apparatus according to the first to eighth inventions, wherein the first and second rotating electrodes are detached from the first and second electrode holders, 1. First and second disk-shaped electrodes for seam welding can be attached to the second electrode holder.

A resistance welding apparatus according to a tenth invention is the resistance welding apparatus according to the first to ninth inventions, wherein at least one of the first and second support mechanisms is attached to a robot arm.

And the resistance welding apparatus which concerns on 11th invention is the resistance welding apparatus which concerns on 1st-10th invention, The said electric power supply means rectifies the alternating current from the inverter which changes a commercial power source into a high frequency, and this inverter, it is direct current | flow A rectifying device is provided.

In the resistance welding apparatus according to the present invention, the first and second rotary welding tips are capable of spot welding with the first and second rotary electrodes facing each other at a specific angular position. Since spot welding is possible, spot welding becomes possible. In this case, since the first and second electrode holders have the first and second rotation driving means, the first and second electrode holders can be held at specific angular positions.
In particular, normal first and second disk-shaped electrodes for performing seam welding can be provided on the first and second electrode holders, and in this case, seal welding is possible.

In particular, when the first and second rotating electrodes are attached to and detached from the first and second electrode holders via the first and second clamping members and the first and second advancing and retracting means, The replacement of the first and second rotating electrodes is facilitated, and not only the manual operation but also the first and second rotating electrodes can be automatically attached and detached.

It is explanatory drawing of the principal part of the resistance welding apparatus which concerns on one embodiment of this invention. (A), (B) is explanatory drawing of the 1st, 2nd rotating electrode of the resistance welding apparatus. (A), (B) is explanatory drawing of attachment and removal of the 1st, 2nd rotating electrode of the resistance welding apparatus. (A), (B) is explanatory drawing which shows the replacement | exchange method of the 1st, 2nd rotating electrode in the resistance welding apparatus. It is a side view of the state which attached the resistance welding apparatus to the robot arm. (A) is explanatory drawing of the use condition of the resistance welding apparatus, (B) is explanatory drawing which shows the other usage example of the resistance welding apparatus.

As shown in FIGS. 1-3, the resistance welding apparatus 10 which concerns on one embodiment of this invention is the 1st, 2nd which becomes the pair each provided in the 1st, 2nd support mechanism 14,15. The electrode holders 16 and 17 have first and second rotating electrodes 18 and 19 that are detachably fixed to the first and second electrode holders 16 and 17, respectively. And it is an example of the 1st, 2nd rotational drive means which respectively rotationally drives the 1st, 2nd electrode holders 16 and 17 which are attached to the 1st and 2nd support mechanisms 14 and 15, respectively and make a pair. The servo motors 22 and 23 with speed reducers and the first and second support mechanisms 14 and 15 are moved relative to each other (in the vertical direction in FIG. 1), and the pair of first and second rotating electrodes 18 and 19 It further includes a pressurizing unit 25 that performs proximity movement, pressurization, and separation movement, and a power supply unit 26 that supplies power to the first and second rotating electrodes 18 and 19. Here, a servo motor without a speed reducer can be used as the first and second rotation driving means.

In the resistance welding apparatus 10 according to this embodiment, as shown in FIGS. 1, 2A, and 2B, the first rotating electrode 18 and the second rotating electrode 19 having the same shape and structure are used. 2, 3 (A), (B), 4 (A), and (B), only the first rotating electrode 18 will be mainly described below.

The first rotating electrode 18 has a front-side (a direction) annular plate portion 20 and a rear-side cylindrical body portion 21 that have an integrated structure, and has a hollow portion 27 in the center of the annular plate portion 20. On the rear side of the hollow portion 27, an annular circular plate portion 27a is provided so as to be aligned with the first rotating electrode 18 in the axial center. The circular plate portion 27a is provided with a non-circular through hole 28 when viewed from the front. As shown in FIGS. 3A and 3B, the through hole 28 has a cylindrical portion 29 provided in the center and a plurality of (in this embodiment, 120 degree uniform angle) radiation expansion provided in the periphery thereof. It has portions (notches) 30 to 32 and constitutes an example of a non-circular notch. In FIG. 1, the details of the first and second rotary electrodes 18 and 19 are partially omitted.

The radial expansion portions 30 to 32 are provided point-symmetrically at three equal positions (that is, positions of 0 degrees, 120 degrees, and 240 degrees in FIG. 3A) with respect to the center of the circular plate portion 27a. Further, the central angular positions of these radiation expansion portions 30 to 32 (that is, positions of 60 degrees, 180 degrees, and 300 degrees in FIG. 3A) have the same shape as the radiation expansion portions 30 to 32 when viewed from the front. The bottom plane recesses 30a-32a are provided. The recesses 30a to 32a are examples of positioning recesses.

As shown in FIGS. 1 and 2A, the first and second rotating electrodes 18 and 19 are the first and second electrodes formed on the front side (direction a) of the intermediate cylindrical members 36 and 37, respectively. The holders 16 and 17 are detachably mounted. In addition, axial rods 34 and 35 are attached to the inner side of the intermediate cylindrical members 36 and 37 so as to be movable in the axial direction. The intermediate cylindrical members 36 and 37 are rotatably provided to the first and second support mechanisms 14 and 15 via a plurality of bearings 39 provided in the axial direction. In FIG. 2A, reference numeral 40 denotes an oil seal. Further, the intermediate cylindrical members 36 and 37 are connected by a key or a spline so as to rotate simultaneously with respect to the axial rods 34 and 35.

The brushes 41 and 42 are in contact with the periphery of the intermediate cylindrical members 36 and 37 made of a good conductor (for example, copper or copper alloy), and supply power to the first and second electrode holders 16 and 17 in the rotating state and the fixed state. The power can be supplied from the means 26. Here, the power supply means 26 includes an inverter that converts commercial power to high frequency, a high-frequency transformer connected to the inverter, and a rectifier circuit (device) connected to the secondary side of the high-frequency transformer, and is spot-welded. Alternatively, the power supply means 26 is operated for a time required for seam welding so that a large current flows between the first and second rotating electrodes 18 and 19. The configuration of the power supply means 26 is well known.

In addition, first and second gears 45 and 46 are provided at intermediate positions of the intermediate cylindrical members 36 and 37 outside the axial rods 34 and 35, and output shafts of the servo motors 22 and 23 with speed reducers. Are meshed with gears 47 and 48 attached to each other. Therefore, the first and second electrode holders 16 and 17 can be rotated by the servo motors 22 and 23 having a rotary encoder therein, and can be stopped at an arbitrary angular position set in advance.

Rear stoppers 50 and 51 are provided at the rear ends of the axial rods 34 and 35 that can move in the longitudinal direction in the intermediate cylinders 36 and 37. In addition, a cylindrical fixing that forms part of the first and second support mechanisms 14 and 15 or is attached to the first and second support mechanisms 14 and 15 is provided at an intermediate position between the shaft rods 34 and 35. The members 50a and 50b have front stoppers 52 and 53 that are rotatably provided via bearings or bushes. Further, springs (compression springs) 54 and 55 are provided between the rear stoppers 50 and 51 and the front stoppers 52 and 53, and always urge the axial rods 34 and 35 backward.

Air cylinders (an example of a cylinder, which may be an electric cylinder) 56 and 57 are provided at the rear portions of the cylindrical fixing members 50a and 50b. The piston rods 58 and 59 of the air cylinders 56 and 57 are moved forward in contact with the rear stoppers 50 and 51 with the air cylinders 56 and 57 extended, and the air cylinders 56 and 57 are contracted. The piston rods 58 and 59 are retracted and the rear stoppers 50 and 51 are retracted by the springs 54 and 55. Valves 61 and 62 are connected to the air cylinders 56 and 57, respectively, and a pressure intensifier 60 for increasing the air pressure is provided in the air source, and the air cylinder 56 is turned on and off by the increased pressure (compressed air). , 57 are activated. The first and second advancing / retreating means are constituted by the springs 54 and 55 and the air cylinders 56 and 57.

The first and second support mechanisms 14 and 15 are connected by a pressurizing unit 25. The pressurizing unit 25 is a guide mechanism that moves the first and second support mechanisms 14 and 15 in a fixed direction. The first and second support mechanisms 14 and 15 are constituted by air cylinders or electric cylinders that serve as driving sources, and the first and second support mechanisms 14 and 15 are pressurized with a constant load or the gap between them is increased. However, since it is a well-known technique, a detailed description is omitted.

As shown in FIGS. 1, 2, and 5, the first and second support mechanisms 14 and 15 are fixed to the front side of the robot arm 63 via the attachment frame 64, and the resistance is controlled by the operation of the robot arm 63. The attitude of the welding apparatus 10 can be freely changed. The robot arm 63 has a well-known structure and is attached to the base 63a.

First and second rotating electrodes 18 and 19 are attached to the first and second electrode holders 16 and 17 on the front side of the intermediate cylindrical members 36 and 37, respectively. O-ring grooves into which sealing O-rings 66 and 67 are fitted are formed in the cylindrical portion 65 of the first electrode holder 16. A cooling water passage 68 is formed in the first rotating electrode 18 that hits the middle position of the O-ring groove, so that the first rotating electrode 18 is water-cooled. The water cooling may be inserted to the inside of the first rotating electrode 18 (the same applies to the second electrode holder 17).

The cooling channels for the intermediate cylinders 36 and 37 may be provided with two channels for going and returning, and one annular pipe is divided by a partition member at the center to form an inner annular path and an outer annular path. Then, a departure path and a return path may be formed. It is preferable to use a rotary joint in a portion for supplying water to the intermediate cylindrical members 36 and 37.

In this embodiment, the first and second rotating electrodes 18 and 19 have the same shape, and have one or a plurality of chip holders 69 and 70 outside the annular plate portion 20. The tip holder 69 provided at the lower end of the first rotating electrode 18 has a first spot welding tip 71, and the tip holder 70 provided at the upper end of the second rotating electrode 19 has a second spot. A welding tip 72 is provided. When spot welding is performed, one tip holder 69 of the first rotating electrode 18 is directed to the second rotating electrode 19, and one tip holder 70 of the second rotating electrode 19 is turned to the first rotating electrode. The first and second spot welding tips 71 and 72 provided on the tip holders 69 and 70 are arranged to face each other.

As shown in FIGS. 1 and 2, first and second crank members 75 and 76 are fixed to the tip portions of the axial rods 34 and 35 disposed so as to be movable back and forth in the intermediate cylindrical members 36 and 37. Has been. The first and second crank members 75, 76 and the shaft rods 34, 35 are connected using a screw mechanism (male screw and female screw) 78a and a hexagon socket head cap screw 78b. 75 and 76 and the shaft rods 34 and 35 are firmly connected in a state where no looseness occurs in the front-rear direction and the rotational direction.

Further, the first clamp member 75 (the same applies to the second clamp member 76) is smaller in non-circular shape than the non-circular through hole 28 formed in the circular plate portion 27a of the first rotating electrode 18. Thus, three arm members 79 to 81 are provided around the central force transmission member 78.
The axial rods 34 and 35 are attached so as not to rotate relative to the intermediate cylinders 36 and 37, but are attached to the intermediate cylinders 36 and 37 so as to be movable back and forth. The first and second clamp members 75 and 76 can be rotated relative to the two rotary electrodes 18 and 19. A cylindrical seal portion 79a is provided at the rear of the force transmission member 78, and cooling water is sealed by an O-ring 79b.

That is, as shown in FIG. 4B, the first and second rotating electrodes 18 and 19 are held by a three-claw chuck 83 which is an example of a gripping member, and the air cylinders 56 and 57 are extended to extend the axial center rod. 34 and 35 are moved forward, the first and second clamp members 75 and 76 are moved forward with respect to the first and second rotating electrodes 18 and 19, and the angles of the arm members 79 to 81 are changed to the radiation expanding portions 30 to 30. 32, and the first and second rotating electrodes 18 and 19 are moved relative to each other to move the first and second rotating electrodes 18 and 19 from the first and second electrode holders 16 and 17, respectively. Can be removed.

On the other hand, when the arm members 79 to 81 are retracted in accordance with the angles of the arm members 79 to 81 to the angles of the recesses 30 a to 32 a, the arm members 79 to 81 are fitted into the recesses 30 a to 32 a, and the first and second The rotary electrodes 18 and 19 are fastened to the first and second electrode holders 16 and 17. This operation is performed by contracting the air cylinders 56 and 57, and the springs 54 and 55 always maintain this state.

Therefore, in this resistance welding apparatus 10, the first and second rotating electrodes 18 are held by the chuck 83 in a state where the first and second rotating electrodes 18 and 19 are released (that is, in a non-pressurized state and a non-fixed state). , 19, the first and second clamp members 75, 76 are advanced, the first and second electrode holders 16, 17 are rotated by a predetermined angle, and the first and second rotating electrodes 18, The first and second rotating electrodes 18 and 19 can be removed and attached by horizontally moving 19 relative to the first and second electrode holders 16 and 17.
Here, the chuck 83 can be attached to another robot arm to form an electrode transport mechanism for attaching and removing the first and second rotating electrodes or the first and second disk-like electrodes.

FIG. 6A shows the use state of the resistance welding apparatus 10, and the first and second spot welding tips provided with the workpieces 85 and 86 as a pair on the first and second rotating electrodes 18 and 19. 71 and 72 are contacted and pressed to perform spot welding. In this case, since the resistance welding apparatus 10 is attached to the robot arm 63, the posture can be freely changed.

FIG. 6B shows an example of welding using the first and second disk-shaped electrodes 88 and 89 instead of the first and second rotating electrodes on which the spot welding tips are mounted. In this case, seam welding can be performed on the workpieces 85 and 86 by continuously energizing or intermittently energizing the first and second disk-shaped electrodes 88 and 89. The replacement of the disk-shaped electrode is not performed by a conventional screw, but is performed by a clamp member, so that workability is greatly improved.

In the resistance welding apparatus 10 shown in FIGS. 2 and 3, the first and second rotary electrodes 18 and 19 each have three tip holders 69 and 70, and the first and second spot welding tips 71 respectively. , 72, as shown in FIGS. 1 and 6A, each of the first and second rotating electrodes 18, 19 has one chip holder 69, 70 and first, second, respectively. It is also possible to provide spot welding tips 71 and 72. The number of spot welding tips attached to one rotating electrode may be single or plural, and the present invention is applied even when the shapes (diameters) are different.

Moreover, in the said embodiment, although the 1st, 2nd clamp member has three arm members, this invention is applied even if it is 2 or 4 or more. In this case, it is preferable that the arm members are arranged in axial symmetry (point symmetry) or line symmetry.

10: resistance welding apparatus, 14: first support mechanism, 15: second support mechanism, 16: first electrode holder, 17: second electrode holder, 18: first rotating electrode, 19: second 20: annular plate part, 21: cylindrical part, 22, 23: servo motor, 25: pressurizing means, 26: power supply means, 27: hollow part, 27a: circular plate part, 28: through hole 29: Cylindrical part, 30-32: Radiation expansion part, 30a-32a: Depression, 34, 35: Axial rod, 36, 37: Intermediate cylindrical material, 39: Bearing, 40: Oil seal, 41, 42: Brush 45: first gear, 46: second gear, 47, 48: gear, 50, 51: rear stopper, 50a, 50b: cylindrical fixing member, 52, 53: front stopper, 54, 55: spring, 56, 57: Air cylinder, 58, 59: Piston rod 60: pressure booster, 61, 62: valve, 63: robot arm, 63a: base, 64: mounting frame, 65: cylindrical portion, 66, 67: O-ring, 68: cooling water passage, 69, 70: Tip holder, 71: First spot welding tip, 72: Second spot welding tip, 75: First clamp member, 76: Second clamp member, 78: Force transmission member, 78a: Screw mechanism, 78b: Hexagon socket head cap screw, 79-81: Arm member, 79a: Seal part, 79b: O-ring, 83: Chuck, 85, 86: Workpiece, 88, 89: Disc-shaped electrode

Claims (11)

A pair of first and second electrode holders respectively provided on the first and second support mechanisms, and first and second rotations detachably mounted on the first and second electrode holders, respectively. Electrodes, first and second rotation driving means attached to the first and second support mechanisms, respectively, for rotating and driving the paired first and second electrode holders, respectively, and the first and second A pressure means for moving the two support mechanisms relative to each other to move the first and second rotating electrodes that are paired together and pressurize and move away from each other, and power to the first and second rotating electrodes. In a resistance welding apparatus provided with power supply means for supplying
The first and second rotating electrodes are provided with first and second spot welding tips capable of spot welding with the first and second rotating electrodes facing each other at a specific angular position. Resistance welding equipment. 2. The resistance welding apparatus according to claim 1, wherein the first and second rotating electrodes are each provided with a non-circular cutout in alignment with an axial center, and inserted into the non-circular cutout at a specific angular position. The second rotating electrode can be removed from the first and second electrode holders, and at other angles, the first and second rotating electrodes are pressed against and fixed to the first and second electrode holders, respectively. The first and second support mechanisms include first and second clamp members and first and second advance / retreat means for advancing and retracting the first and second clamp members, respectively. Resistance welding equipment. 3. The resistance welding apparatus according to claim 2, wherein the first and second advancing / retreating units each include a spring and a cylinder, and the first and second clamp members biased by the spring are the first and second clamping members. The second rotating electrode is always pressed against the first and second electrode holders, the cylinder is driven to oppose the spring, and the first and second clamping members are moved to the first and second rotations. A resistance welding apparatus characterized by being separated from an electrode. 4. The resistance welding apparatus according to claim 3, wherein the compressed air that drives the cylinder is pressurized through a pressure intensifier. 5. The resistance welding apparatus according to claim 2, wherein the first and second rotating electrodes are the first and second clamping members, and the first and second rotating electrodes are the first and second rotating electrodes. 1. A resistance welding apparatus having a positioning recess into which the first and second clamp members are fitted when pressed against the second electrode holder. 6. The resistance welding apparatus according to claim 2, wherein, apart from the first and second support mechanisms, the first and second rotating electrodes are sandwiched and rotated by a predetermined angle, 1. A resistance welding apparatus provided with an electrode transport mechanism for removing and attaching the first and second rotating electrodes, which are not fixed by the first and second clamp members. The resistance welding apparatus according to any one of claims 1 to 6, wherein the first and second rotation driving means are servo motors. 8. The resistance welding apparatus according to claim 1, wherein each of the first and second rotating electrodes includes a single or a plurality of the first and second spot welding tips. 9. Resistance welding equipment. 9. The resistance welding apparatus according to claim 1, wherein the first and second rotating electrodes are detached from the first and second electrode holders, and seams are formed on the first and second electrode holders. A resistance welding apparatus characterized in that first and second disk electrodes for welding can be attached. 10. The resistance welding apparatus according to claim 1, wherein at least one of the first and second support mechanisms is attached to a robot arm. 11. The resistance welding apparatus according to claim 1, wherein the power supply means includes an inverter that changes a commercial power source to a high frequency and a rectifier that rectifies alternating current from the inverter to direct current. Resistance welding equipment.

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