JP2003220473A - Resistance welding machine and resistance welding method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a resistance welding machine capable of making a structure simple and compact and easily conducting high quality welding while ensuring high centering precision, and a resistance welding method therefor. <P>SOLUTION: A welding part of a first work 6 is placed on a lower electrode 5, and a second work 7 is placed on the first work 6. The second work 7 is centered at a centering face 20a of an upper enroll member 20b. When an upper electrode 3g is lowered by operation of a cylinder, the upper enroll member 20b is pressed by a pressing member 28, as a result, both the upper and a lower inlay members 20b and 20c are lowered. A wedge effect by a synergistic operation work of a tapered face 20d and a tapered face 23d applies a force to a collet type centering part 23c at the upper part of a collet type centering jig 23 in the orthogonal direction to the vertical direction, and expands them. A centering face 23a of the collet type centering jig 23 is closely brought into face-contact with the inner peripheral face of the first work 6, as a result, the first work 6 is centered with high precision. After that, the welding parts of the first and second forks 6 and 7 are welded. <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 metal member (hereinafter also referred to as a work) for joining a rotary shaft to a hub of a clutch used in an automatic transmission of an automobile, and other metal members (hereinafter, referred to as a work). (Also called work) belongs to the technical field of resistance welding machines and resistance welding methods for joining
The present invention belongs to the technical field of a resistance welding machine that is compact and inexpensively formed while having a high centering accuracy of a work, and a resistance welding method capable of easily performing high-quality welding.

[0002]

2. Description of the Related Art Conventionally, an automatic transmission used in an automobile has a planetary gear unit having a plurality of rotating elements, and a plurality of friction members each having a clutch or a brake for engaging or locking the plurality of rotating elements. An automatic transmission having a coupling element and a hydraulic control device for controlling the operation of the friction engagement element are provided. Further, a hydraulic servo is generally used to operate a friction engagement element of an automatic transmission.

For these rotary elements and hydraulic servos, for example, metal members such as gear parts whose rotary shafts are welded to gears and clutch parts whose rotary shafts are welded to a hub of a clutch, and other metal members. Welded parts in which and are welded are often used. Conventionally, resistance welding has generally been employed for welding welding parts in such automatic transmissions.

FIG. 3 is a diagram schematically showing a resistance welding machine generally adopted for performing such resistance welding. As shown in FIG. 3, the resistance welding machine 1 is fixed to a base 4 and an upper electrode 3 (corresponding to a first electrode of the present invention) which is vertically moved by a cylinder 2 (corresponding to a driving means of the present invention). The lower electrode 5 (corresponding to the second electrode of the present invention), the first work 6 which is the rotating shaft of the gear of the welding part of the automatic transmission, and the second work which is its tubular gear member during welding. First and second clamping means 8 and 9 for clamping 7 in a centered state, and a voltage applying device 10 for applying a voltage between the upper and lower electrodes 3 and 5 are provided.

The first clamp means 8 includes a first clamp cylinder 11, a first centering jig 12 which is operated by the first clamp cylinder 11 to center the first work 6, and a second clamp. Cylinder 13 and the second workpiece 7 operated by the second clamp cylinder 13.
And a second centering jig 14 for centering.

The first centering jig 12 holds the outer circumference of the first work 6 and has a first jig member 15 having a tapered surface 15a on the outer circumference of the holding portion, and the first clamping cylinder 1.
1, the taper surface 16a formed on the inner circumference
The second jig member 1 for clamping the first work 6 at the centering position by the wedge effect generated in cooperation with the tapered surface 15a.
6 and. Similarly, the second centering jig 14 includes a third jig member 17 that holds the outer circumference of the second work 7 and has a tapered surface 17 a on the outer circumference of the holding portion, and a second clamping cylinder 13. The fourth jig member 18 that is actuated and clamps the second work 7 at the centering position by the wedge effect generated by the tapered surface 18a formed on the inner periphery in cooperation with the tapered surface 16a is provided.

The welding operation of the conventional resistance welding machine 1 thus constructed will be described. First, the welded portion of the first work 6 is placed on the upper end surface of the lower electrode 5, and the first work is performed. The second work 7 is placed on top of 6. Then
The first and second clamp means 8 and 9 are operated to clamp the first and second workpieces 6 and 7, respectively, at the centering positions. Next, the cylinder 2 is operated to lower the upper electrode 3 to bring the lower end surface of the upper electrode 3 into contact with the second work 7,
And the welded parts of the second workpieces 6 and 7 are placed on the upper and lower electrodes 3, 5
Clamp between the two. In this state, the voltage application device 10 applies a predetermined voltage between the upper and lower electrodes 3 and 5 to weld the welded portions of the first and second workpieces 6 and 7. Thus, the first and second works 6 and 7 are joined by resistance welding. According to this resistance welding machine 1, since the first and second workpieces 6 and 7 are centered with high accuracy, it is possible to manufacture high quality welded parts.

However, in the conventional resistance welding machine 1, the first clamping means 8 having the first clamping cylinder 11 and the first centering jig 12, the second clamping cylinder 13 and the second centering jig are provided. Since the second clamp cylinder 13 having 14 is required, not only the centering structure is complicated but also the number of parts is large. Moreover, since the first and second centering jigs 12 and 14 are arranged on the outer circumferences of the first and second workpieces 6 and 7, respectively, the centering structure becomes large and the resistance welding machine 1 is installed. There is a problem that a lot of space is required. Further, since three cylinders 2, 11, 13 are required, not only is control of these cylinders troublesome, but there is also a problem that the cost is high.

Due to these problems, it is difficult for the conventional resistance welding machine 1 shown in FIG. 3 to flexibly and efficiently cope with resistance welding of various types of welding parts, and it is necessary to change the centering jig and perform daily routines. There is also the problem that management of is complicated.

Under these circumstances, a resistance welding machine using a spigot type centering jig has been proposed. FIG. 4 is a view schematically and partially showing an example of a resistance welding machine using a conventional spigot / spigo type centering jig. In FIG. 4, the right half shows the state before the lower electrode descends, and the left half the upper electrode descends and the welded parts of the first and second workpieces are clamped between the upper and lower electrodes. It shows the state. In the following description, the same components as those of the example described before the description are given the same reference numerals,
Detailed description thereof will be omitted.

As shown in FIG. 4, the resistance welding machine 1 of this conventional example includes a first clamping means 8 having a first clamping cylinder 11 and a first centering jig 12 of the above-mentioned example, and a second clamping means. And a second clamp cylinder 13 having a second centering jig 14 are not provided,
Instead, a cylindrical first spigot type centering jig 19 having a centering surface 19a on the outer periphery of the upper end portion and a second spigot type centering jig 20 having a centering surface 20a on the outer periphery of the upper end portion are provided. There is. The other structure of the resistance welding machine 1 of this conventional example is the same as the example shown in FIG.

In the resistance welding machine 1 of this conventional example, first, the first spigot type centering jig 19 is placed in the recess of the upper end of the lower electrode 5, and at least a part of the centering surface 19a is the upper end of the lower electrode 5. Fit so that it projects further upward. Then, the second spigot type centering jig 20 is placed in the inner peripheral hole of the first spigot type centering jig 19, and at least a part of the centering surface 20 a is located above the upper end of the first spigot type centering jig 19. Fit so that it protrudes.

Then, similarly to the above-mentioned example, the welded portion of the first work 6, which is, for example, the hub of the clutch of the welding part of the automatic transmission, is placed on the upper end surface of the lower electrode 5, and the first work is carried out. The second work 7, which is the axis of rotation, is placed on 6. At this time, the first work 6 is centered on the centering surface 19a of the projecting first spigot type centering jig 19, and the centering surface of the projecting second spigot type centering jig 20 is performed. The second work 7 is centered at 20a.

In this state, the welded portions of the first and second workpieces 6 and 7 are clamped between the upper and lower electrodes 3 and 5 in the same manner as in the above-described example, and then a predetermined voltage is applied by the voltage applying device 10. By applying a voltage between the upper and lower electrodes 3 and 5, the welded portions of the first and second workpieces 6 and 7 are welded. Thus, the first and second works 6 and 7 are joined by resistance welding.

According to the resistance welding machine 1 using such a spigot-type centering jig, the first and second spigot-types having a simple structure without using the first and second clamp means 8 and 9 are provided. Since the centering jigs 19 and 20 are arranged on the inner peripheral sides of the lower electrode 5 and the upper electrode 3, respectively, the resistance welding machine 1 does not become large and various problems such as the conventional example shown in FIG. Can be resolved.

FIG. 5 is a view similar to FIG. 4, schematically and partially showing another example of a resistance welding machine using a conventional taper / spigot type centering jig. In the example shown in FIG. 4 described above, two first and second spigot type centering jigs 1 are used.
9 and 20, the resistance welding machine 1 of this conventional example does not use the first spigot type centering jig 19 as shown in FIG. 5, but instead, the centering surface inclined to the outer periphery of the upper end portion is used. Two
A taper type centering jig 21 having 1a is used.
Further, this taper type centering jig 21 is provided so as to be vertically movable with respect to the lower electrode 5, and
A spring 22 that is compressed between and is always urged upward. The other structure of the resistance welding machine 1 of this conventional example is the same as the example shown in FIG.

In the conventional resistance welding machine 1, the first work 6 is not directly placed on the upper end surface of the lower electrode 5 before the upper electrode 3 is lowered as shown in the right half of FIG.
The taper type centering jig 21 is placed on the inclined centering surface 21a. In this state, the second work 7 is placed on the first work 6 as described above. Then, as shown in the left half of FIG. 5, when the cylinder 2 is operated to press the second work 7 via the upper electrode 3, the second and first works 7, 6 are
And the taper type centering jig 21 are both springs 22.
Then, the welded portion of the first work 6 is placed on the upper end surface of the lower electrode 5 as in the above-described examples. At this time, the first work 6 is centered on the inclined centering surface 21a of the tapered centering jig 21. Other operations of the resistance welding machine 1 of this conventional example are the same as those of the example shown in FIG.

According to the resistance welding machine 1 using such a spigot type centering jig, it is possible to solve various problems as in the conventional example shown in FIG. 3 as in the example shown in FIG. You can

[0019]

However, in the resistance welding machine 1 using the spigot type centering jig of the example shown in FIG. 4, the first and second spigot type centering jigs 19,
Although 20 has a simple structure, since there is a clearance between each of the centering surfaces and the inner peripheral surfaces of the first and second workpieces 6 and 7, the centering accuracy is deteriorated by the clearance. There's a problem.

On the other hand, in the resistance welding machine 1 using the spigot type centering jig of the example shown in FIG. 5, the taper type centering jig 21 having the inclined centering surface 21a is used. Although the centering accuracy is higher than that of the resistance welding machine 1 of the example shown in FIG. 4, since the tapered surface of the centering surface 21a and the inner peripheral edge of the first work 6 make line contact, these contacts become unstable. Since it is easy, there is a problem that the centering accuracy is lower than that of the resistance welding machine 1 of the example shown in FIG. In particular, since the first work 6 is not placed on the upper end surface of the lower electrode 5 before the upper electrode 3 is lowered, the posture of the first work 6 is likely to be unstable, and the centering accuracy is further lowered. I will end up.
Therefore, the resistance welding machines 1 of the examples shown in FIG. 4 and FIG.
Then, there is room for further enhancing the centering accuracy.

The present invention has been made in view of the above circumstances, and an object thereof is to make the structure simple and compact, and to simplify the control and to further improve the centering accuracy. It is to provide an inexpensive resistance welding machine that can be secured.

Another object of the present invention is to be able to flexibly and efficiently cope with resistance welding of various types of welding parts, and to simplify the setup change of the centering jig and daily management. It is to provide a resistance welding machine.

Another object of the present invention is to provide a resistance welding method capable of easily performing high quality welding while ensuring high centering accuracy of a work.

[0024]

In order to solve the above-mentioned problems, the resistance welding machine according to the invention of claim 1 moves the first electrode toward the second electrode by the driving means to move the first electrode to the first electrode. Resistance welding is performed by applying a voltage between the first electrode and the second electrode while the welded portion of the first work and the welded portion of the second work are sandwiched between the two electrodes. In the resistance welding machine for performing the above, a collet-type centering member having a centering surface for centering at least one of the first and second workpieces formed on the outer periphery is disposed on the inner periphery of the second electrode, The collet type centering member is provided with an expanding member for expanding the centering surface forming portion of the collet type centering member, and the first electrode is provided with a pressing member for pressing the expanding member, and the driving means. When the first electrode is moved to the second electrode by the pressing member, Open member is pressed, by centering surface forming part of the collet-type centering elements are expanded,
At least one of the first and second workpieces is centered.

Further, in the resistance welding machine according to the invention of claim 2, when the expanding member is formed with a tapered surface and the collet type centering member is formed with a tapered surface, the expanding member is pressed. And a centering surface forming portion of the collet type centering member expands due to a wedge effect generated by cooperation of the tapered surface of the expanding member and the tapered surface of the collet type centering member. .

Further, the resistance welding machine according to a third aspect of the invention is characterized in that the first and second workpieces are welding parts used in an automatic transmission.

Further, the resistance welding method of the invention of claim 4 is
While the first electrode is moved toward the second electrode and the welded portion of the first work and the welded portion of the second work are sandwiched between the first electrode and the second electrode, these first In the resistance welding method of performing resistance welding by applying a voltage between the first electrode and the second electrode, the first and second electrodes are formed on the inner circumference of the second electrode.
A collet type centering member having a centering surface for centering at least one of the workpieces is formed on the outer periphery, and the centering surface forming portion of the collet type centering member is provided on the collet type centering member. A spreading member for spreading is provided,
By moving the first electrode to the second electrode and pressing the expanding member with the pressing member to expand the centering surface forming part of the collet type centering member, the first and second electrodes are formed. It is characterized in that at least one of the works is centered.

[0028]

According to the resistance welding machine of the present invention having the above-mentioned constitutions, the collet arranged on the inner circumference of the second electrode can be provided by the resistance welding machine 1 of this example. Since at least one of the first and second workpieces is centered on the centering surface of the die centering member, it is possible to significantly improve the centering accuracy of the workpiece as compared with the conventional resistance welding machine. This makes it possible to produce very high quality welded parts easily and inexpensively. In particular,
If both the first and second workpieces are centered on the centering surface of the collet type centering member, the centering accuracy of the workpiece can be maximized.

Further, since the collet type centering member having a simple structure is arranged on the inner peripheral side of the second electrode, the centering structure is provided as compared with the case where the conventional centering member is externally attached to the outer periphery of the electrode. The resistance welding machine can be formed compactly. As a result, it is possible to save space in the resistance welding machine, and moreover, since only the driving means for driving the first electrode is required, the welding operation can be easily controlled and the cost can be reduced. .

Therefore, since it is possible to flexibly and efficiently cope with resistance welding of various types of welded parts, the replaceability of the centering jig can be improved and daily management of the resistance welding machine becomes easy. In that case, the first means provided with drive means
If the work located on the electrode side is made common to each component, it is only necessary to replace the work on the second electrode side, which is not provided with the driving means, the collet type centering member and the expanding member, so that the centering The exchangeability of the members can be improved more effectively.

In particular, according to the resistance welding machine of the second aspect of the invention, the collet type centering member is produced by the wedge effect generated by the cooperation of the tapered surface of the expanding member and the tapered surface of the collet type centering member. The centering structure can be further simplified by expanding the centering surface forming portion.

According to the resistance welding machine of the third aspect of the present invention, the welding parts of the automatic transmission are welded by the resistance welding machine of the present invention, so that they can be manufactured easily, with high accuracy, and at low cost. You can Therefore, the shift control of the automatic transmission can be performed stably and reliably, and the reliability of the automatic transmission can be improved.

On the other hand, according to the resistance welding method of the invention of claim 4, it is possible to easily perform high-quality welding while ensuring high centering accuracy of the work.

[0034]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a view similar to FIGS. 4 and 5, schematically and partially showing an example of an embodiment of a resistance welding machine and a resistance welding method of the present invention.

In the conventional example shown in FIG. 4, the two first
Although the second spigot type centering jigs 19 and 20 are used, the resistance welding machine 1 of this example does not use the first spigot type centering jig 19 as shown in FIG. A cylindrical collet type centering jig 23 having a centering surface 23a on the outer periphery of the part is used. The collet type centering jig 23 is arranged on the inner circumference of the lower electrode 5 similarly to the first spigot type centering jig 19. At this time, at least a part of the centering surface 23 a is projected above the upper end of the lower electrode 5.

The collet type centering jig 23 (corresponding to the collet type centering member of the present invention) is provided with a thin portion 23b, and this thin portion 23b is elastically deformable in a direction orthogonal to the vertical direction in the drawing. Has become. Also, the thin portion 2
A collet type centering portion 23c is provided on the upper portion of 3b, and the centering surface 2 is provided on the outer periphery of the collet type centering portion 23c.
3a is provided and the collet type centering part 2 is provided.
A tapered surface 23d is formed on the inner periphery of 3c.

The second spigot type centering jig 20 of this example has an upper spigot member 20b and a lower spigot member 2.
0c (corresponding to the expanding member of the present invention) and divided into two members. The lower spigot member 20c is provided through the collet type centering jig 23 so as to be slidable in the vertical direction, and at the same time as shown in the figure by a spring 24 provided between the collet type centering jig 23 and the collet type centering jig 23. It is biased upward. In that case, when the upper electrode 3 is in the raised position, the lower spigot member 20c is set to the upper limit position shown in the right half of FIG. 1 by the stopper 20e provided at the lower end thereof.

These upper and lower spigot members 20
The b and 20c are integrated by fitting a protrusion formed on the lower surface of the upper spigot member 20b into a recess formed on the upper surface of the lower spigot member 20c.

A centering surface 20a is formed on the outer periphery of the upper spigot member 20b. Also, the lower spigot member 2
On the outer periphery of the upper end portion of 0c, a tapered surface 20d that cooperates with the tapered surface 23 to generate a wedge effect and generate a force in a direction orthogonal to the vertical direction is formed. The second spigot type centering jig 20 may be formed of a single member without being divided.

Further, at the center of the upper electrode 3, a protruding shaft 26
Are provided so as to extend downward. Protruding shaft 26
In the lower part, an axial hole 27 that opens to the lower end is formed, and in the axial hole 27, a pressing member 28 that can press the upper spigot member 20b downward is slidably provided. When the upper electrode is in the raised position, the pressing member 28 is set to the lower limit position shown in the right half of FIG. A spring 29 is arranged between the protruding shaft 26 and the pressing member 28.

As described above, in the resistance welding machine 1 of this example, the centering of the first work 6 is the collet type centering, and the centering of the second work 7 is the spigot type centering. It is configured as a spigot resistance welding machine 1. The other structure of the resistance welding machine 1 of this example is the same as that of the conventional example shown in FIG.

Next, the welding operation of the resistance welding machine 1 of this example,
That is, the resistance welding method of this example will be described. As shown in the right half of FIG. 1, first, as in the case of the conventional example shown in FIG. 4, the welded portion of the first work 6, which is the hub of the clutch of the welding part of the automatic transmission, is attached to the lower electrode 5. The second work 7 which is the rotation shaft thereof is placed on the first work 6 while being placed on the upper end surface. At this time, the first work 6 is relatively roughly centered on the centering surface 23a of the projecting collet type centering jig 23, and the upper inlay member 2 of the second spigot type centering jig 20 projecting.
The second work 7 is centered on the centering surface 20a of 0b as in the conventional example shown in FIG.

In this state, when the cylinder 2 is operated to lower the upper electrode 3 as in the conventional example shown in FIG. 3, the protruding shaft 2
6 and the pressing member 28 are also lowered. Then, after the pressing member 28 contacts the upper spigot member 20b, the pressing member 28 pushes the upper spigot member 20b downward to further descend, so that the spring 24 contracts and the upper and lower spigot members 20b, 20c are contracted. Both descend.

When the lower spigot member 20c is lowered, the collet on the upper part of the collet type centering jig 23 is produced by the wedge effect generated by the cooperation of the tapered surface 20d and the tapered surface 23d as shown in the left half of FIG. The mold centering portion 23c is expanded by applying a force in a direction orthogonal to the vertical direction. As a result, the centering surface 23a of the collet type centering jig 23 comes into close surface contact with the inner peripheral surface of the first work 6, so that the first work 6 is centered with high accuracy. At this time, the upper spigot member 20b does not escape from the second work 7 even if it descends, and the centering of the second work 7 by the centering surface 20a of the upper spigot member 20b is maintained.

When the upper electrode 3 further descends, the upper and lower spigot members 20b and 20c do not descend further, so the pressing member 28 does not descend, and the spring 29 contracts so that the pressing member 28 moves above the protruding shaft 26. The upper electrode 3 and the protruding shaft 26 descend together.

Then, as shown in the left half of FIG. 1, after the lower end of the upper electrode 3 comes into contact with the welded portion of the second work 7, the first and second works 6 and 7 are formed in the same manner as in the above-mentioned examples. The part to be welded is clamped between the upper and lower electrodes 3, 5. In this state, the voltage application device 10 applies a predetermined voltage between the upper and lower electrodes 3, 5 to weld the welded portions of the first and second workpieces 6, 7. Thus, the first and second works 6 and 7 are joined by resistance welding.

When the welding is completed, the upper electrode 3 is raised by the cylinder 2. Then, first, the contracted spring 29 extends, so that the pressing member 28 and the upper and lower spigot members 20b and 20c do not rise, but the upper electrode 3 and the protruding shaft 26 rise. The pressing member 28 is the protruding shaft 26.
On the other hand, when the initial lower limit position is reached, the spring 29 does not extend any further, so that the pressing member 28 ascends as the upper electrode 3 and the protruding shaft 26 ascend. Then, the urging force of the reduced spring 24 also raises the upper and lower spigot members 20b, 20c, so that the cooperation between the tapered surface 20d and the tapered surface 23d is canceled, the wedge effect disappears, and the collet type centering portion 23c. Is released, and the collet type centering portion 23c is reduced to the initial state by the elasticity of the thin portion 23b.

Finally, when the upper electrode 3 reaches the upper limit value, the operation of the cylinder 2 is stopped, and the upper electrode 3, the protruding shaft 26, the pressing member 38, the upper and lower spigot members 20b, 20.
Both c are in the initial inoperative state shown in the right half of FIG. Other operations of the resistance welding machine 1 of this example are the same as those of the conventional example shown in FIG.

According to the resistance welding machine 1 of this example, the first work 6 is centered by the centering surface 23a of the collet type centering jig 23 arranged on the inner circumference of the lower electrode 5.
The centering accuracy of the first work 6 can be significantly increased as compared with the resistance welding machine 1 of the conventional example shown in FIG. This makes it possible to produce very high quality welded parts easily and inexpensively.

Further, like the above-mentioned conventional example shown in FIG. 4,
First and second clamping means 8 and 9 of the conventional example shown in FIG.
Moreover, since the collet type centering jig 23 and the second spigot type centering jig 20 both having a simple structure are arranged on the inner peripheral side of the lower electrode 5, the centering structure can be simplified. The resistance welding machine 1 can be made compact. This makes it possible to save space in the resistance welding machine 1, and since only one cylinder 2 is required, the welding operation can be easily controlled and the cost can be reduced.

Therefore, since it is possible to flexibly and efficiently cope with resistance welding of various types of welded parts, exchangeability of the centering jig can be improved and daily management of the resistance welding machine 1 becomes easy. In that case, if the second work 7 is made common to each component, it is only necessary to replace the first work 6, the collet type centering jig 23 and the second spigot type centering jig 20 on the side without the cylinder. The exchangeability of the centering jig can be improved more effectively.

Moreover, by welding welded parts such as clutches, brakes, and gear parts of the automatic transmission with the resistance welder 1 of this example, it is possible to easily, highly accurately and inexpensively manufacture the parts. Therefore, it is possible to perform the shift control of the automatic transmission stably and surely,
The reliability of the automatic transmission can be improved.

On the other hand, according to the resistance welding method of this example, it is possible to easily perform high-quality welding while ensuring high centering accuracy of the work. Other effects of the resistance welding machine 1 and the resistance welding method of this example are the same as those of the conventional example shown in FIG.

FIG. 2 is a view similar to FIGS. 1, 4 and 5, which schematically and partially shows an example of the embodiment of the resistance welding machine and the resistance welding method of the present invention. The collet type centering jig 23 of the example shown in FIG. 1 has a thin portion 23b and a collet type centering portion 23c having a centering surface 23a. However, as shown in FIG. In the machine 1, the collet type centering jig 23 is not provided with the collet type centering portion 23c having the thin portion 23b and the centering surface 23a. Further, in the collet type centering jig 23 of the example shown in FIG. 1, the tapered surface 23d is formed on the inner periphery of the upper end portion, but in the resistance welding machine 1 of this example, the tapered surface 23d is the collet type centering jig. It is formed on the outer periphery of the upper end portion of 23.

The resistance welding machine 1 of this example does not have the second spigot type centering jig 20 of the example shown in FIG.
Instead, it has a second collet type centering jig 25 (corresponding to the expanding member of the present invention). In the following description of the resistance welding machine 1 of this example, the above-described collet type centering jig 23 is referred to as a first collet type centering jig 23 for convenience of description.

The second collet type centering jig 25 is similar to the lower spigot member 20c of the example shown in FIG.
At the upper end of the collet type centering jig 25, a tapered surface 25a similar to the tapered surface 20d of the lower spigot member 20c is formed. Further, the second collet type centering jig 25 slidably penetrates the first collet type centering jig 23 and is constantly urged upward by the spring 30. Further, the second collet type centering jig 2
At the lower end of 5, the lower spigot member 20c of the example shown in FIG.
A stopper 31 similar to the stopper 20e of FIG. 2 is provided. With this stopper 31, when the upper electrode 3 is in the raised position, the second collet type centering jig 25 is set to the upper limit position shown in the right half of FIG. Has been done.

As shown in the left half of FIG. 2, when the upper electrode 3 descends, the pressing member 28 is moved to the second collet type centering jig 25.
The second collet type centering jig 2 by directly contacting the upper surface of the
5 is pressed downward.

Further, in the resistance welding machine 1 of this example, the cylindrical double (W) collet type centering is performed between the taper surfaces 23a and 25a of the first and second collet type centering jigs 23 and 25, respectively. A member 32 is provided. Upper and lower centering surfaces 32a and 32b are formed on the outer circumferences of the upper and lower ends of the W collet type centering member 32, respectively. Further, on the inner circumferences corresponding to these centering surfaces 32a and 32b, a tapered surface 32c that cooperates with the tapered surface 25a to generate a wedge effect, and a tapered surface 23a that cooperates with the tapered surface 23a to generate a wedge effect. A tapered surface 32d is formed. Due to these wedge effects, the upper and lower ends of the W collet type centering member 32 are elastically deformed and expanded.

As described above, the resistance welding machine 1 of this example is constructed as a collet / collet resistance welding machine 1 in which the centering of the first and second workpieces 6 and 7 is a collet type centering. . The other structure of the resistance welding machine 1 of this example is the same as the example shown in FIG.

Next, the welding operation of the resistance welding machine 1 of this example,
That is, the resistance welding method of this example will be described. As shown in the right half of FIG. 1, first, similarly to the example shown in FIG. 1, the welded portion of the first work 6 which is the hub of the brake of the welding member in the automatic transmission is placed on the lower electrode 5. The second work 7 which is the inner race of the one-way clutch of the welding member in the automatic transmission is placed on the first work 6 while being placed on the end face. At this time, the second work 7 is relatively roughly centered by the upper centering surface 32a and the first work 6 is centered by the lower centering surface 32b.
Is relatively coarsely centered.

Then, similarly to the example shown in FIG.
When the second collet type centering jig 25 is lowered, the pressing member 28 pushes the second collet type centering jig 25, and the second collet type centering jig 25 is lowered. The mold centering member 32 also descends. Further, when the collet type centering member 32 is lowered, the tapered surface 25a and the tapered surface 32c are formed as shown in the left half of FIG.
And cooperate to generate a wedge effect and the tapered surface 23
The d and the tapered surface 32d cooperate with each other to generate a wedge effect, and the upper end and the lower end of the collet type centering member 32 are elastically deformed and expanded by applying a force in a direction orthogonal to the vertical direction.

As a result, the upper centering surface 32a of the collet type centering jig 32 comes into close surface contact with the inner peripheral surface of the second work 7, and the lower centering surface 32b of the collet type centering jig 32 comes to the first side. Since the inner peripheral surfaces of the one work 6 are in close contact with each other, the first work 6 is accurately centered.

When the upper electrode 3 is lifted up after welding is completed, the above-mentioned double wedge effect disappears, so that the upper and lower ends of the expanded collet type centering member 32 are elastically contracted. As a result, the collet type centering member 32 moves up by the cooperation of the tapered surface 23d and the tapered surface 32d, and returns to the initial non-operating position shown in the right half of FIG. Other operations of the resistance welding machine 1 of this example are the same as those of the example shown in FIG.

According to the resistance welding machine 1 and the resistance welding method of this example, the upper and lower centering surfaces 32a and 32b of the collet type centering member 32 arranged on the inner circumference of the lower electrode 5 are provided.
Since the second work 7 and the first work 6 are centered respectively, the respective centering precisions of the first and second works 6 and 7 can be both increased.
As compared with the resistance welding machine 1 of the example shown in FIG. 1, extremely high quality welded parts can be easily manufactured at low cost. Other effects of the resistance welding machine 1 and the resistance welding method of this example are the same as those of the example shown in FIG.

In each of the above examples, only the first work is centered by the collet type, or both the first and second works are centered by the collet type.
It is also possible to center the second work only with a collet type. Further, in each of the above-described examples, the two electrodes are arranged in the vertical direction, but these two electrodes may be arranged in any direction such as the horizontal direction.

Further, although the resistance welding machine and the resistance welding method of the present invention are applied to the welding parts of the automatic transmission for explanation, the present invention is not limited to this, and it can be applied to the parts of the automatic transmission. Not limited to this, it can be applied to resistance welding work of any component (work).

[Brief description of drawings]

FIG. 1 is a diagram schematically and partially showing an example of an embodiment of a resistance welding machine and a resistance welding method according to the present invention.

FIG. 2 is a view similar to FIG. 1 schematically and partially showing another example of the embodiment of the resistance welding machine and the resistance welding method according to the present invention.

FIG. 3 is a diagram schematically showing a resistance welding machine that has been conventionally generally used for welding welding parts of an automatic transmission.

FIG. 4 is a view similar to FIG. 1, schematically showing an example of a conventional spigot / spigot type resistance welding machine.

FIG. 5 is a view similar to FIG. 1, schematically showing an example of a conventional taper / spigot type resistance welding machine.

[Explanation of symbols]

1 ... Resistance welding machine, 2 ... Cylinder, 3 ... Upper electrode, 4 ... Base, 5 ... Lower electrode, 6 ... 1st work, 7 ... 2nd work,
DESCRIPTION OF SYMBOLS 10 ... Voltage application device, 20 ... 2nd spigot type centering jig, 20a ... Centering surface, 20b ... Upper spigot member, 2
0c ... lower spigot member, 20d ... tapered surface, 23 ...
Collet type centering jig, 23a ... Centering surface, 23b ... Thin portion, 23c ... (First) collet type centering part, 23d ...
Tapered surface, 25 ... Second collet type centering jig, 25a
... Tapered surface, 26 ... Projecting shaft, 28 ... Pressing member, 32 ...
Double (W) collet type centering member, 32a ... upper centering surface, 32b ... lower centering surface, 32c, 32d ... tapered surface

Claims (4)

[Claims] 1. The drive means moves the first electrode toward the second electrode to sandwich the welded portion of the first work and the welded portion of the second work between the first electrode and the second electrode. In a resistance welding machine that performs resistance welding by applying a voltage between the first electrode and the second electrode in a pressed state, centering for centering at least one of the first and second workpieces. A collet type centering member whose surface is formed on the outer periphery is arranged on the inner periphery of the second electrode, and the centering surface forming portion of the collet type centering member is expanded on the collet type centering member. An opening member is provided, and a pressing member that presses the expanding member is further provided on the first electrode, and the expanding member is pressed by the pressing member when the driving unit moves the first electrode to the second electrode. The centering surface forming portion of the collet type centering member expands. And, the resistance welding machine which is characterized in that at least one centering of the first and second workpiece. 2. A taper surface is formed on the expanding member, and a taper surface is formed on the collet type centering member. When the expanding member is pressed, the taper surface of the expanding member and the collet are formed. 2. The resistance welding machine according to claim 1, wherein the centering surface forming portion of the collet type centering member expands due to a wedge effect generated in cooperation with the taper surface of the die centering member. 3. The first and second workpieces are welded parts used in an automatic transmission.
Or the resistance welding machine according to 2. 4. The first electrode is moved toward the second electrode to move the first electrode.
Applying a voltage between the first electrode and the second electrode in a state in which the welded portion of the first work and the welded portion of the second work are sandwiched between the electrode and the second electrode. In the resistance welding method of performing resistance welding with a collet type centering member, the centering surface for centering at least one of the first and second workpieces is formed on the outer periphery on the inner periphery of the second electrode. The collet type centering member is provided with an expanding member for expanding the centering surface forming portion of the collet type centering member, and the first electrode is moved to the second electrode to move the first electrode to the second electrode. At least one of the first and second workpieces is centered by pressing the expanding member with a pressing member to expand the centering surface forming portion of the collet type centering member. Resistance welding method.