JPH0952179A - Resistance welding equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve reliability and maintainability of welding gun. SOLUTION: Upper/lower yorks 1, 2 are pivotally supported with a spindle 6 and held with a gun bracket 7. Further, washers 8 having insulation are interposed on the facing faces 1a, 2a of upper/lower yorks and the facing face 7a of a gun bracket. Further the washer 8 are fixed to one side of facing faces. That is, the substantial sliding faces when opening/closing upper/lower yorks are consisting of the insulation washer 8 fixed to facing face 1a and the facing face 2a, between the upper york 1 and lower york 2, and the facing face 2a, between the lower york 2 and gun bracket 7. Further, an annular grooves 16 are formed on both side faces of insulation washer 8 and coaxially with the insulation washer 8, insulation members 17 are fitted to the annular grooves 16 and the sliding faces are covered. Thus, expulsion is not directly penetrated into sliding face.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the structure of a rotary shaft portion that pivotally supports a gun yoke of a resistance welding device, and more specifically,
The present invention relates to a structure for improving the hermeticity and wear resistance of the rotary shaft portion.

[0002]

2. Description of the Related Art In resistance welding, a welding speed is fast and productivity is good, and welding parameters are high because the materials to be welded are pressed by opposing electrodes and joined by utilizing resistance heat generated by short-time energization of a large current. It is easy to control and suitable for automation, it does not require consumable materials such as welding rods, is low cost, does not require high processing precision for plate matching of the joint, has little welding deformation, and has stable quality, Although it has excellent characteristics, it requires large equipment and is suitable for mass production fields such as the automobile industry.

FIG. 31 shows a resistance welding device, particularly a welding gun portion, for applying pressure and current to a material to be welded.
The welding gun has a pair of yokes, an upper yoke 1 and a lower yoke 2, each of which is driven around a rotary shaft portion 3. Arms 4 and 5 provided with electrodes 23 are attached to the tips of the upper yoke 1 and the lower yoke 2 so as to face each other.

Further, the structure of the rotary shaft portion 3 is shown in FIG.
The upper yoke 1 and the lower yoke 2 share the main shaft 6.
A thread groove (not shown) is formed at the end of the main shaft 6,
The main shaft 6 is fixed to the gun bracket 7 by screwing the nut 25 through the washer 24. By the way, if the upper yoke 1 and the lower yoke 2 are short-circuited at the rotating shaft portion 3, it becomes impossible to conduct electricity at the tip portion of the electrode 23. Therefore, the facing surface 1 between the upper yoke 1 and the lower yoke 2
Insulating washers 8 are interposed and fixed by pins 9 and the like on a, 2a, and the facing surfaces 2a, 7a of the lower yoke 2 and the gun bracket 7 that holds the rotary shaft portion 3 therebetween. Further, by interposing insulating bushes 13 and 12 between the upper yoke 1 and the bearing 11 and between the lower yoke 2 and the bearing 10, the upper yoke 1 and the lower yoke 2 are electrically connected via the main shaft 6. To prevent that.

Resistance welding is performed by the welding gun having the above structure. By the way, when performing a welding operation, a molten metal called splatter is scattered from the welded portion of the material to be welded while solidifying. This scattering is a very fine particle, and the facing surfaces 1a, 2 of the upper and lower yokes are
a and the facing surface 7a of the gun bracket, and the insulating washer 8
May penetrate even a small gap between and. If the dust spreads into these gaps, the upper and lower yokes 1 and 2 and the insulating washer 8 are worn, and the gaps are widened.
It is easier to infiltrate the spatter, and the spatter enters the bearings 10 and 11 to damage the bearing. In addition, rattling caused by bearing damage causes wear of the bearing mounting holes of the upper and lower yokes 1 and 2. ,
Problems such as electrolytic corrosion of the bearings 10 and 11 and the main shaft 6 due to scattering will occur. Therefore, the rotary shaft portion 3 finally causes a large backlash.

Therefore, in order to protect the rotary shaft portion 3 from the scattered high temperature, a cover 14 as shown in FIG. 33 has conventionally been provided. The cover 14 is made of a flame-retardant rubber plate or the like. Also, as indicated by the diagonal lines in FIG.
There is also an example in which a metal plate having a hinge that bends according to the operation of the lower yokes 1 and 2 is used as the cover 14.

[0007]

However, the structure for protecting the rotary shaft portion 3 from the scattering by the cover 14 has the following drawbacks. If the cover 14 is made of a flame-retardant rubber, the high-temperature dispersion accumulates on the cover 14 while repeating the scattering, and a crack is generated.
There was a risk that the dust would get inside. Further, when the cover 14 is a metal plate with a hinge, there is a possibility that the spatter may enter the hinge and be damaged, the spatter may enter through a gap generated by the damage, or the welding gun may malfunction. In any case, it is difficult to shut off the rotary shaft portion 3 from being scattered over a long period of time, and maintenance such as periodic disassembly and cleaning of the rotary shaft portion and replacement of parts has been indispensable.

Further, even if it is possible to sufficiently prevent scattering from entering the sliding surfaces of the insulating washer 8 and the facing surfaces 1a and 2a of the upper and lower yokes and the facing surface 7a of the gun bracket 7.
While the upper and lower yokes 1 and 2 are repeatedly opened and closed, wear of the sliding contact surface, the bearing mounting holes of the upper and lower yokes 1 and 2, the main shaft 6, and the like progresses, and eventually the rotating shaft portion 3 is loosened. It will cause a relationship. At present, in order to correct the rattling, the nut 25 is tentatively processed by further tightening. Further, as a permanent measure, when correcting the cross-sectional shape of the main shaft 6 which has been deformed due to wear, the bearing mounting holes of the upper and lower yokes 1 and 2, etc., the rotary shaft portion 3 is disassembled into each component unit and processed. I had to go to the opportunity. Therefore, it was impossible to make a correction with the gun bracket installed on the welding line. Further, even if the overhaul is performed, minute wear may be overlooked, and the service life of the welding gun after repair may be reduced to 1/3 that of a new product. Therefore, it is not possible to obtain an effect commensurate with the number of man-hours and costs required for the large-scale disassembly and correction.

The present invention has been made in view of the above problems. An object of the present invention is to provide a deep layer portion of a rotating shaft portion with a structure in which foreign matter such as dust is difficult to mix. The aim is to improve the reliability of the welding gun, and ultimately to improve the welding quality and reduce the product cost. Further, even if the components of the rotary shaft portion are deformed due to wear, the repair can be easily performed.

[0010]

Means for Solving the Problems According to the present invention for solving the above problems, a pair of yokes are coaxially supported and sandwiched by a gun bracket, and an opposing surface between the pair of yokes, and An intervening washer having an insulating property is fixed to one of the facing surfaces between the one of the pair of yokes and the gun bracket, and the washer is fixed to one of the facing surfaces that face each other. It is characterized in that a cover for covering the periphery of the sliding surface is provided.

According to the present invention, the washer having an insulating property is fixed to one of the facing surfaces between the pair of yokes and one of the facing surfaces between the one of the pair of yokes and the gun bracket. Substantial sliding surface when opening and closing,
It is formed by a washer and a facing surface on which the washer is not fixed. A cover is provided to cover this sliding surface so that the ends of the sliding surfaces of the washers are not exposed.

Further, in the present invention, it is desirable that the washer comprises a pair of washer pieces at least one of which has an insulating property, and each washer piece is fixed to an adjacent facing surface.

With this configuration, the insulating properties of the opposing surfaces with the washer interposed are secured, and the contact surface between the pair of washer pieces is a substantial sliding surface in the opening / closing operation of the pair of yokes. Further, a cover is provided on the peripheral end portions of the pair of washers to cover the peripheral end portions of the pair of washers,
Do not expose the end of the sliding surface.

Further, in the present invention, the cover is
It is desirable that at least one peripheral end portion of the pair of washer pieces be formed with a protrusion that covers the other peripheral end portion.
With this configuration, the ends of the sliding surfaces that are formed by the washer pieces and that are substantially in the opening / closing operation of the pair of yokes are covered with the washers themselves.

Further, in the present invention, at least one of the pair of washer pieces has a multilayer structure including an elastic material layer having insulating properties and flame retardancy, and the outer periphery of the elastic material layer having insulating properties and flame retardancy. It is also possible to integrally form a cover for covering the outer peripheral portion of the other washer on the portion.

In this case, by covering the outer peripheral portion of the other washer with the cover formed on one of the pair of washer pieces, the ends of the sliding surface formed by the washers are not exposed. Further, the cover is formed integrally with the outer peripheral portion of the elastic material layer and can be flexibly deformed. Therefore, when the cover is assembled, the cover is elastically deformed so as not to buffer other parts. Furthermore, the insulating property of the washer is ensured by including the elastic material layer.

As a means for solving the above problem, according to the present invention, a pair of yokes are pivotally supported by a main shaft and are sandwiched by a gun bracket, and the opposing surfaces between the pair of yokes and the pair of yokes. A pair of washer pieces, at least one of which has an insulating property, are fixed to the opposing surfaces between the one and the gun bracket, and the washer is provided on the contact surface between the washer pieces. A groove that opens at the outer peripheral portion of the washer piece is formed so as to avoid the main shaft hole.

In the present invention, the contact surface between the pair of washer pieces is a substantial sliding surface in the opening / closing operation of the pair of yokes. Then, by collecting the spatter that enters the sliding surface from the peripheral end portions of the pair of washer pieces in the groove and positively discharging the spatter from the groove to the outside, the spatter does not reach the main shaft. To do.

As another means for solving the above problems, according to the present invention, a pair of yokes are coaxially supported and clamped by a gun bracket, and the sliding surfaces of the pair of yokes have insulating resistance. It is characterized in that an abradable layer is formed and a cover for covering the end portion of the sliding surface is provided.

In the present invention, by forming an insulating wear-resistant layer on the sliding surfaces of the pair of yokes, the sliding surfaces themselves have insulating properties and wear resistance. Further, the end of the sliding surface is covered with a cover so as not to be exposed.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the accompanying drawings. In the figure, the same or corresponding parts as those of the conventional example are designated by the same reference numerals, and detailed description thereof will be omitted.

FIG. 1 shows a sectional view of a rotary shaft portion 3 of a welding gun according to a first embodiment of the present invention.
The upper and lower yokes 1 and 2 of the welding gun are bearings.
The main shaft 6 is rotatably supported via the shafts 10 and 11, and the upper yoke 1 is further sandwiched by the lower yoke 2. The outer surface of the lower yoke 2 is held by the gun bracket 7.

Insulating bushes 12 and 13 are interposed between the upper and lower yokes 1 and 2 and the bearings 10 and 11. Also,
An insulating washer 8 is interposed between the facing surfaces 1a and 2a of the upper yoke 1 and the lower yoke 2 and the facing surfaces 2a and 7a of the lower yoke 2 and the gun bracket 7, respectively. The conduction between 10, 11 and the gun bracket 7 is prevented. The insulating washer 8 has a facing surface 1a facing each other by an engaging member 15 such as a screw and a fixing pin.
Alternatively, it is fixed to either one of the opposite surfaces 2a and 7a.

Therefore, in this embodiment, the substantial sliding surface when the upper and lower yokes 1 and 2 are opened and closed is an insulating member fixed to the facing surface 1a between the upper and lower yokes 1 and 2. The lower yoke 2 is constituted by the washer 8 and the facing surface 2a.
Between the gun bracket 7 and the gun bracket 7, an insulating washer 8 fixed to the gun bracket 7 and the facing surface 2a are provided.

Also, on both sides of the insulating washer 8,
Further, an annular groove 16 surrounding the peripheral end portion of the insulating washer 8 is formed so as to be concentric with the insulating washer 8, and an insulating member 17 is fitted into the annular groove 16 as a cover for covering the periphery of the sliding surface. There is. By the way, the insulating member 17 is formed so as to project several millimeters from the surfaces of the upper and lower yokes 1 and 2 and the gun bracket 7. If there is no protrusion, the insulating washer 8 and the insulating member 17 electrically separate the upper and lower yokes 1 and 2 from each other, or
A short circuit may easily occur between the lower yoke 2 and the gun bracket 7 via the conductive dust accumulated on the surface.

However, when the insulating member 17 is projected, the amount of scattered particles is deposited so as to rise on the protruding insulating member 17 and the members on both sides thereof, and the upper and lower yokes 1, 2 or Only when the yoke 2 and the gun bracket 7 are connected to each other, conduction is established. Therefore,
By removing the scattering before reaching this state, the function of the insulating member 17 as an insulating partition can be maintained. That is, compared to the case where the insulating member 17 is not projected, it is not necessary to frequently perform the dust removal work. In this way, the insulating member 17 is projected and the rotating shaft portion 3 is occasionally
It has been empirically clarified that the removal of the dust accumulated on the surface can prevent the short circuit due to the dust.

Next, the insulating member 17 will be described with reference to FIGS.
Will be described. The insulating member 17 shown in FIG. 2 is an annular member having a rectangular cross section and a partial cutout. As the material, an insulating elastic member rich in heat resistance and water resistance, such as acetal resin or fluorine resin, is suitable.
When the insulating member 17 is attached, the notch is deformed so as to be widened, and the annular groove 16 is inserted from the side of the rotating shaft portion 3 so that the annular member 16 is fitted and the elastic restoring force of the insulating member 17 is utilized to form an annular shape. The groove 16 is closely attached.

Further, the sectional shape of the insulating member 17 is not limited to the rectangular section, but may be one having a chamfered portion 17a as shown in FIG. 3 (a) or a side surface (for example, as shown in FIG. 3 (b)). It is also possible to use those having fine protrusions 17b (which form an annular shape). When the chamfered portion 17a is provided, fitting into the annular groove 16 becomes easy. In this case, in order to improve the airtightness,
It is desirable to form a chamfer in the annular groove 16 so as to coincide with the chamfer 17a. When the fine protrusions 17b are formed on the side surfaces, the surface pressure on the annular groove 16 is concentrated on the protrusions 17b, so that the contact surface pressure on the protrusions 17b is increased and the hermeticity can be further enhanced.

Further, as shown in FIG. 4, it is possible to use a two-divided insulating member 18. This insulating member 18 also
An acetal resin or the like is used to form an annular shape by combining one insulating member 18a and the other insulating member 18b. In this case, as shown in FIG. 5, the joint portions at both ends partially overlap each other, and a convex portion 18c and a concave portion 18d are formed in the overlapping portions so that they are fitted to each other. At the time of mounting, first, the other insulating member 18b
Is fitted in the annular groove 16, and later, both ends of one insulating member 18a are opened slightly outward and attached so as to engage with 18b, whereby the elastic restoring force of one insulating member 18a causes
One insulating member 18a and the other insulating member 18b are fixed.

Further, as shown in FIG. 6, it is possible to fix the end portion of the insulating member 19 divided into two parts with an engaging member 20 such as a screw or a fixing pin. In this case, since it is not necessary to deform the insulating member 19 itself at the time of mounting, it is possible to select a harder material. Further, a ring having a circular or rectangular cross section formed of a rubber material can be used as the insulating member. In any case, the insulating member
It is desirable that any of 17 to 19 be fitted into the annular groove 16 so that no gap is created.

The operation and effect obtained from the first embodiment of the present invention having the above configuration are as follows. Between the upper and lower yokes 1 and 2, a substantial sliding surface when the upper and lower yokes 1 and 2 are opened and closed is constituted by an insulating washer 8 fixed to the facing surface 1a and a facing surface 2a. An insulating washer 8 fixed to the gun bracket 7 and a facing surface 2a are provided between the lower yoke 2 and the gun bracket 7. Further, the insulating washer 8 extends over both side surfaces of the insulating washer 8 and is concentric with the insulating washer 8. The annular groove 16 is formed so that
An insulating member 17 is fitted in. That is, the substantially sliding surface when the upper and lower yokes 1 and 2 are opened and closed can be covered with the insulating member 17. Therefore, the scattering does not directly fly to the peripheral end of the sliding surface, and a step is provided on the path from the sliding surface end to the center to lengthen the path, and By fitting the insulating member 17 into the groove 16 so as not to create a gap, it is possible to prevent scattering from entering the sliding surface.

Even if the sliding surface gets into the scattering surface, since the step is formed on the sliding surface and the distance to the center portion is lengthened, the scattering is generated in the rotating shaft portion. It becomes difficult to penetrate deep into the sea. Therefore, it is possible to prevent the decrease in reliability of the welding gun, which has been conventionally caused by the intrusion of dust. Therefore, maintenance-free operation can be promoted, which can greatly contribute to reduction of product cost.

Next, a second embodiment of the present invention will be described with reference to FIG. In the second embodiment, detailed description of the same or corresponding parts as in the first embodiment will be omitted.

The feature of this embodiment is that the insulating member 21, which is a cover for covering the periphery of the sliding surface when the upper and lower yokes are opened and closed, is arranged not inside the surface of the rotating shaft portion 3 but inside. An annular groove 22 for holding the insulating member 21 is formed at a predetermined intermediate portion of each sliding surface. The insulating member 21 used in the present embodiment is optimally a ring having a circular cross section or a rectangular cross section formed of a rubber material from the viewpoint of assembling. It is also possible to form the insulating washer 8 from a rubber material and form the insulating member 21 integrally with the insulating washer 8.

Also in the second embodiment of the present invention having the above configuration, the substantial sliding surface when the upper and lower yokes 1 and 2 are opened and closed is set between the upper yoke 1 and the lower yoke 2 by: Opposing surface 1
The insulating washer 8 fixed to a and the facing surface 2a are provided. Between the lower yoke 2 and the gun bracket 7, the insulating washer 8 fixed to the gun bracket 7 and the facing surface 2 are provided.
a, the insulating member 21 cuts off the intermediate portion of the sliding surface, and an annular groove 22 is formed in the intermediate portion to form a step on each sliding surface. The road to the club is getting longer. Therefore, the same effect as that of the first embodiment can be obtained. Also, the first
By using the embodiment and the second embodiment in combination, a more effective seal structure can be formed.

By the way, the configurations of the first and second embodiments having the above-mentioned configurations are summarized as follows. That is, the resistance welding device sandwiches a pair of coaxially rotatable yokes with a gun bracket, and an insulating washer is provided on a sliding surface of the pair of yokes and a sliding surface of one of the pair of yokes and the gun bracket. And the insulating member is arranged so as to be concentric with the insulating washer across both sliding surfaces of the insulating washer.

Next, a third embodiment of the present invention will be described with reference to FIGS. In the third embodiment, the same or corresponding parts as those in the first embodiment are designated by the same reference numerals, and detailed description thereof will be omitted.

FIG. 8 shows a sectional view of the rotating shaft portion 3 of the welding gun according to the third embodiment of the present invention. Here, the difference from the structure of the rotating shaft portion 3 in the first embodiment will be described. An insulating bush 26 is driven into the spindle mounting hole 701 of the gun bracket 7, and the spindle 6 is attached to the gun bracket 7 via the bush 26.
Is supported by. Further, the split pin 27 penetrates through the nut 25 and the main shaft 6 and is fixed in position so that the nut 25 for fixing the main shaft 6 to the gun bracket does not loosen.

When the bearings 10 and 11 are radial roller bearings, insulating bushes 12 and 13 are provided between the bearing mounting holes of the upper and lower yokes 1 and 2 and the bearings 10 and 11 as shown in the figure. Intervene. Also bearing
In the case where so-called OILES bearings 10 and 11 are formed of oil-impregnated metal or the like, the oil-impregnated metal itself is made to have insulating properties, and the insulating bushes 12 and 13 are omitted.

The facing surface 1a between the upper yoke 1 and the lower yoke 2,
2a, a facing surface 2a between the lower yoke 2 and the gun bracket 7,
A pair of washers 28 (hereinafter, also simply referred to as washers) made up of washer pieces 28a and 28b are interposed in the 7a. By making at least one of the washer pieces 28a, 28b have an insulating property, the washer 28 is an insulating washer. The washer pieces 28a, 28b are fixed to the facing surfaces 1a, 2a or 7a adjacent to each other by engaging members 29 such as screws and stop pins.

That is, in the third embodiment,
A substantial sliding surface when the upper and lower yokes 1 and 2 are opened and closed is a washer piece 28a between the upper yoke 1 and the lower yoke 2 and between the lower yoke 2 and the gun bracket 7. It is constituted by a contact surface with the washer piece 28b.

By the way, the main shaft 6 is provided with a grease passage 30. The grease path 30 has an opening at one end of the main shaft,
In order to be able to lubricate each bearing 10, 11,
It consists of a main path 30a extending in the axial direction and a sub path 30b branching from the main path 30a in the radial direction and reaching the surface of the main axis.
Further, a collar 31 is arranged between the bearings 11 which support the upper yoke, and an appropriate gap is provided to form a grease chamber 32 for storing grease. Therefore, bearings 10, 11
The grease can always be supplied to the bearings, and the life of the bearings 10 and 11 can be extended. Reference numeral 6a is a connector for connecting a supply means (not shown) for supplying grease to the grease chamber 32 during maintenance or the like.

Now, the washer 28 will be described in detail. As shown in FIG. 10, the washer 28 is a washer piece 28a.
And a washer piece 28b, each of which has a disk shape. In addition, a washer piece
By making the 28a and 28b closely contact with each other, wall-shaped projections 33a and 33b are formed at the respective peripheral end portions as a cover for covering the other peripheral end portion. A gap C ₁ (indicated by an arrow in FIG. 8) is provided between the protrusion 33a and the peripheral end of the washer piece 28a, and between the protrusion 33b and the peripheral end of the washer piece 28b. This gap C ₁ is provided by the washer pieces 28a, 28b.
The dimensions are set so that they do not interfere with each other's sliding movements and do not easily scatter. In addition, the protrusion
One end of 33a, 33b is brought into contact with the washer piece 28a,
When the 28b is brought into close contact, the protrusion 33
A gap C ₂ is formed between the other ends of a and 33b. Further, in the disk-shaped portions of the washer pieces 28a, 28b, engaging member holes 34 for fixing the washer pieces to the facing surfaces 1a, 2a of the upper and lower yokes and the facing surface 7a of the gun bracket, A main shaft hole 35 for inserting the main shaft 6 is bored.

As described above, the substantial sliding surface when the upper and lower yokes 1 and 2 are opened and closed is the washer piece 28a and the washer piece 28.
Although it is constituted by a contact surface with b, the peripheral end portion of the sliding surface is covered with the projections 33a, 33b formed on the washer pieces 28a, 28b. Therefore, the protrusions 33a, 33b
By arranging either one of them in the direction in which the scattering occurs, it is possible to prevent the scattering from directly entering from the sliding surface end portion to the sliding surface deep layer portion. Further, as shown in FIG. 8, the outer diameters of the washer pieces 28a and 28b are set so as to project from the surfaces of the upper and lower yokes 1 and 2 and the gun bracket 7 by several millimeters, and the upper and lower yokes 1 and 2 and It is empirically clear that even if some scattering is accumulated on the surface of the gun bracket 7, the scattering can be prevented from entering the sliding surface through the gap C ₁ by occasionally removing the accumulated scattering. Has become.

By the way, as a material used for the washer pieces 28a, 28b, a resin material such as acetal resin, nylon resin, oil-impregnated metal having an insulating property and an insulating metal material are suitable. , It forms a substantial sliding surface when the upper and lower gun yokes are opened and closed. Further, if at least one of the washer pieces 28a and 28b has an insulating property, the insulating property of the washer 28 configured by combining the both is guaranteed, so that a copper-based material or the like may be used as the other material. It is possible. A point to be noted here is that a magnetic material such as an iron-based material is not suitable as a material for a washer piece because it may generate heat due to the influence of a magnetic field generated during welding work.

When selecting the washer pieces 28a and 28b, by selecting a material having the same or lower abrasion resistance than the materials of the upper and lower yokes 1 and 2 and the gun bracket 7, the upper and lower yokes are selected. Wear caused by opening and closing of 1 and 2 is positively caused on the washer pieces 28a and 28b,
The upper and lower yokes 1 and 2 and the gun bracket 7, which are not easily replaced, can always maintain their regular shapes. Therefore, by replacing only the washer 28 that is worn due to long-term use, it is possible to return to a state similar to that of a new product.

For reference, the material used for the spindle 3 is
Generally, heat-treated carbon steel for machine structures such as S45C is used, which is hard chrome plated and has high wear resistance and rust prevention. The upper and lower yokes 1 and 2 are made of high-strength brass or beryllium-copper alloy.

Next, points to be noted when incorporating the washer 28 into the rotary shaft portion 3 will be described with reference to FIGS. 8 and 9. FIG. 9 is an exploded view of the rotary shaft portion 3 of the welding gun shown in FIG. As shown in FIG. 9, the protrusion 33a of the washer piece 28a
Is fixed to the facing surface 2a of the lower yoke so as to face the tip direction of the upper and lower yokes 1 and 2 which is the direction of the scattering. Further, the protrusion 33b of the washer piece 28b is directed toward the rear end direction of the upper and lower yokes 1 and 2, and fixed to the facing surface 1a of the upper yoke and the facing surface 7a of the gun bracket. Then, as shown by an arrow B in FIG. 9, the upper yoke 1 is incorporated into the lower yoke 2 from the upper side to the lower side. Further, the gun bracket 7 is incorporated into the lower yoke 2 from the rear to the front as shown by an arrow D. By installing in this way, the washer piece
The protrusions 33a and 33b provided on the 28a and 28b are assembled in the state shown in FIG. 8 without interfering with each other.

By the way, as shown in FIG.
A gap C ₂ is formed between the protrusions 33a and 33b of the 28a and 28b. This is provided to allow the relative rotation angle θ between the washer piece 28a and the washer piece 28b when the swing angle of the upper and lower yokes 1 and 2 is θ. Therefore,
The clearance C ₂ is preferably set as small as possible in consideration of the swing angle θ of the upper and lower yokes 1, 2. In the example of FIG. 13, a protrusion 33a is formed over the half circumferential portion of the circumferential end portion of one washer piece, and at the circumferential end portion of the other washer piece, a range shorter than the gap C ₂ is provided. The protrusion 33b is formed by.

Further, by devising the method of taking the clearance C ₂ and the mounting direction of the washer pieces, the washer pieces 28a, 28b have the same shape and the mounting directions are opposite to each other so that the washer pieces 28a, 28b are common parts. It is also possible to For example, when the swing angles θ of the upper and lower yokes 1 and 2 are the same, the washers 28a and 28b are formed at the same position and in the same shape, and the protrusions 33a and 33b are formed so as to allow rotation of θ / 2. The washer pieces 28a and 28b can obtain the relative rotation angle θ.

The operational effects obtained from the third embodiment of the present invention having the above-mentioned structure are as follows. A washer piece 28 is provided on the facing surfaces 1a, 2a of the upper yoke 1 and the lower yoke 2, and the facing surfaces 2a, 7a of the lower yoke 2 and the gun bracket 7.
By interposing a pair of washers 28a and 28b and fixing the washer pieces 28a and 28b to the adjacent facing surfaces, the contact surface between the washer pieces 28a and 28b is opened and closed by the pair of yokes 1 and 2. The substantial sliding surface at. Then, a protrusion 33 is provided at the peripheral end of the washer pieces 28a, 28b.
By forming a and 33b and covering the sliding surface, it is possible to prevent dust from directly entering the sliding surface. Therefore, it is possible to prevent substantial wear of the sliding surfaces during the opening / closing operation of the pair of yokes 1 and 2, which would lead to damage of the rotary shaft portion 3. Further, the projections 33a and 33b can prevent water from entering the bearing portion of the main shaft from the sliding surface, and have an effect of preventing trouble due to rusting of the bearing.

In addition, at least one of the washer pieces 28a, 28b is provided with an insulating property so as to ensure the insulating property between the opposed surfaces with the washer interposed, and at the same time, prevent the scattering of the invasion of the bearing 10 by the scattering. , 11 and the main shaft 6 can be prevented from having problems such as electrolytic corrosion. As described above, as a cover for covering the contact surface between the washer pieces 28a, 28b, the projection 33 is provided at the peripheral end portion of the washer pieces 28a, 28b.
It is desirable to form a projection covering the other peripheral end portion by forming a and 33b. With this configuration, the end of the sliding surface formed by the washer pieces can be covered with the washer itself, and the washer piece 28a,
Since 28b can be the same component, it is possible to prevent an increase in the number of components.

The applied shape of the washer 28 in the third embodiment will be introduced below with reference to FIGS. 11, 12 and 14 to 20. The washer 28 shown in FIG. 11 is a washer piece 28c,
It consists of a combination of 28d. The washer piece 28c has a disk shape, and a protrusion 33c is formed over a half circumference portion of the circumferential end portion thereof. Further, the washer piece 28d has a simple disk shape. In the example of FIG. 11, the projection 33c of the washer piece 28c is used in the scattering direction when the scattering direction is concentrated in one direction and the accumulation amount is not so large.

The washer 28 shown in FIG. 12 is a washer piece 28.
It consists of a combination of d and 28e. The washer piece 28e is
The lower half of the washer piece 28c shown in FIG. 11 is rectangular and further has a protrusion 33e formed by extending the end of the protrusion 33c along the rectangular end. In the example of FIG. 12, since the protrusion 33e formed on the washer piece 28e can cover the ends of the contact surfaces of the washer pieces 28d and 28e over a wide area without a break, the blocking property of scattering is very high. Become.

Next, the sectional shape of the washer 28 in the thickness direction will be described with reference to FIGS. 14 to 18. FIG. 14 shows a cross-sectional shape of the washer 28 shown in FIG. As described above, the gap C ₁
Has a necessary minimum dimension so as not to hinder the sliding of the washer pieces 28a and 28b and prevent the washer pieces from easily entering. The washer 28 shown in FIG. 15 has a small protrusion 36 in the form of a band or a spiral formed on at least one of the protrusion 33f and the peripheral end of the washer piece 28g so as to block the gap C ₁ from the outside. By providing the small protrusions 36, frictional resistance that hinders the sliding of the washer pieces 28f and 28g does not occur, and the blocking property of scattering can be significantly improved.

The washer 28 shown in FIG. 16 is a washer piece 28j.
A large diameter part 37 is provided at the peripheral end of the
It is formed in 33h. According to this structure, a step is provided on the way from the entrance of the gap C ₁ to the sliding surfaces of the washer pieces 28h and 28j, and the blocking property of scattering can be significantly improved. In the washer 28 shown in FIG. 17, the peripheral end portion of the washer piece 28m is formed in a conical shape, and the protrusion 33k has a shape corresponding to this. According to this configuration,
It is possible to extend the path from the entrance of the clearance C ₁ to the sliding surfaces of the washer pieces 28k, 28m, and improve the blocking property of scattering.

Further, FIG. 18 shows a simple disk-shaped washer piece as a pair of washer pieces constituting the washer 28.
The case where two 28d are used is shown. In this case, a circular ring 38 having a concave cross section is used as a cover for covering the periphery of the sliding surfaces of the washer pieces 28d, 28d. The circular ring 38
As shown in FIG. 19, it is composed of divided pieces 38a and 38b, and is easily attached and detached. Further, as shown in FIG. 20, the divided pieces 38a,
At the end of 38b, a hook-shaped fixing portion 38 for engaging with each other is provided.
c and 38d are formed.

Next, a fourth embodiment of the present invention will be described with reference to FIGS. 21 and 22. In the fourth embodiment, detailed description of the same or corresponding parts as in the first to third embodiments will be omitted.

The fourth embodiment is a further application example of the washer 28 in the third embodiment. Therefore, only the differences from the third embodiment will be described below. FIG. 21 shows a part of a cross-sectional view of the washer 40 according to the fourth embodiment. The washer 40 is composed of a pair of washer pieces 41 and 42. Further, the washer piece 41 includes an intermediate layer 43 formed of an elastic material having insulating properties and flame retardancy, a resin material such as acetal-based resin, nylon-based resin, oil-impregnated metal having insulating property, and insulating metal material. It is sandwiched between the surface layers 44 formed in 1. and each layer is fixed by rivets 45. The washer piece 42 has a single-layer structure using an insulating material or a metal material other than a magnetic material. Reference numeral 48 in the drawing indicates a spindle hole.

Further, a washer piece is provided on the outer peripheral portion of the intermediate layer 43.
A cover 46 that is in close contact with the peripheral edge portion of 42 is integrally formed. Furthermore, on the contact surface of the cover 46 with the peripheral edge of the washer piece 42,
A small protrusion 47 having a strip shape or a spiral shape is formed.
As shown in FIG. 22, even if the protrusion 47 is not formed, frictional resistance that prevents sliding is not generated. Materials suitable for the intermediate layer 43 include ozone resistant silicon, fluorosilicone, and the like. The ozone-resistant material is used to prevent the intermediate layer from being deteriorated by the effect of ozone generated in the welding environment.

The operational effects obtained from the fourth embodiment of the present invention having the above structure are as follows. Washer
Since the intermediate layer 43 of the washer piece 41 forming the 40 is formed of an elastic material having insulating properties and flame retardancy,
The surface layer 44 of 41 and the material of the washer piece 42 do not need insulation. Further, since the cover 46 that covers the periphery of the substantial sliding surface (the contact surface of the washer pieces 41 and 42) when the upper and lower yokes 1 and 2 are opened and closed is formed integrally with the intermediate layer 43, When the shaft portion is assembled, the cover can be elastically deformed so as not to interfere with other components. Therefore,
The assembly direction is not restricted, and the assemblability is improved. In the above description, the case where only the washer piece 41 has a multi-layered structure has been described, but a structure in which both the washer pieces 41 and 42 have a multi-layered structure, and the sliding surface is alternately covered with the cover integrally formed on the intermediate layer is adopted. If so, the hermeticity is further improved. Other than that, the description of the same effects as those of the third embodiment will be omitted.

Next, a fifth embodiment of the present invention will be described with reference to FIGS. In the fifth embodiment, detailed description of the same or corresponding parts as in the first to fourth embodiments will be omitted.

Also in the fifth embodiment of the present invention, the structure of the washer 49 is different from that of the other embodiments. As shown in FIG. 23, the washer 49 is composed of a pair of washers, namely washer pieces 49a and 49b. These washer pieces 49a, 49b
Are on a simple disk. Then, as in the third embodiment, at least one of the washer pieces 49a and 49b is made of an insulating material. However, when the pair of yokes is opened and closed, the sliding surfaces (washers 49a, 49a
A cover for covering the periphery of the contact surface b) is not provided. Instead, on the sliding surface of the washer piece 49a, the spindle hole 50
A groove 51 that opens at the outer peripheral portion of the washer 49 is formed so as to avoid. The depth of the groove 51 is about 1 to 2 mm. Then, the groove 51 is arranged so as to intersect with the direction of scattering, and in front of the spindle hole 50 (at a position closer to the point where scattering occurs).

In this embodiment, the washer pieces 49a, 49b, which are substantially sliding surfaces when the pair of yokes are opened and closed, are used.
Since the contact surface of is exposed, the dust penetrates the sliding surface. However, even if the dust penetrates, the spindle hole 50
Before reaching the groove 51, it is captured by the groove 51 and is positively discharged to the outside from the opening 51a of the groove 51. In order to enhance the function of capturing the dust and discharging it to the outside, as shown in FIG.
You may provide the V-shaped groove 52 avoiding this. Further, as shown in FIG. 25, avoid the main shaft hole 50 from the middle of the groove 51, and
It is also possible to form 53, 54 in a direction intersecting the groove 51.
Further, as shown in FIG. 26, a washer piece 49a is provided with a V-shaped groove 52, and a washer piece 49b (not shown) is provided with concentric grooves 55, 56 as shown by a dotted line, and further opened to the outside. However, it is also possible to provide a connecting groove 57 that connects the grooves 55 and 56. In this case, by capturing the spillage that is missed by the concentric circular groove 55 by the groove 56 and discharging it to the outside from the V-shaped groove 52 and the connecting groove 57, it is possible to further improve the discharge capability of the splatter. . In addition, as shown in FIG.
By avoiding 50 and providing a plurality of stages of parabolic grooves 58, 59, it is also possible to capture and discharge dust.

However, even when any of the above-mentioned groove shapes is used, the opening portions of the grooves should not be oriented in the direction of scattering. The reason is that if the openings of the grooves are oriented in the direction in which splattering occurs, the splatters directly enter the inside of the grooves through the openings and accumulate inside.

As a function and effect obtained from the fifth embodiment of the present invention having the above structure, a pair of washer pieces 49 is provided.
Dispersion that invades inside from the peripheral edge of the contact surface of a, 49b,
It is possible to prevent the dispersion from reaching the spindle hole 50 by catching the dispersion with the grooves 51 to 59 and positively discharging the dispersion from the groove to the outside. Moreover, even if it is not possible to provide a cover that substantially covers the periphery of the sliding surface when the pair of yokes is opened and closed as described in the third and fourth embodiments, the scattering is caused by the deep layer of the sliding surface. It is possible to prevent invasion into the department. Therefore, it is possible to prevent water from entering the bearing portion located in the deep portion of the sliding surface, and as in the third embodiment, there is also an effect of preventing trouble due to bearing rusting. Further, since there are no protrusions on the peripheral end portions of the washer pieces 49a and 49b, there is no restriction on the assembling direction when assembling the rotating shaft portion.

Next, a sixth embodiment of the present invention will be described with reference to FIGS. In the sixth embodiment, detailed description of the same or corresponding portions as those of the conventional example or the first to fifth embodiments will be omitted.

FIG. 28 shows a sectional view of the rotary shaft portion 3 of the welding gun according to the sixth embodiment. The feature of the present embodiment is that, instead of the insulating washer used in each of the above-described embodiments, the facing surfaces 1a, 2 of the upper and lower yokes 1, 2 are
The point is that an insulating abrasion-resistant layer is formed on a. Therefore, since the facing surfaces 1a and 2a are substantially sliding surfaces when the upper and lower yokes 1 and 2 are opened and closed, the facing surfaces 1a and 2a are referred to as sliding surfaces 1a and 2a only in the present embodiment. .

As an example of the method of forming the insulating wear resistant layer, the case where the sliding surfaces 1a, 2a are coated with a ceramic will be described. The thickness of the ceramic coating layer is several microns to several millimeters. Ceramics have very high wear resistance and are usually wear-free. Therefore, the problem that the sliding surfaces 1a, 2a are worn and rattling is virtually eliminated. However, if foreign matter such as dust penetrates the sliding surfaces 1a, 2a and scratches the ceramic coating layer, damage to the ceramic layer may spread from there. In order to prevent this, the covers 60 and 61 that cover the end surfaces of the sliding surfaces 1a and 2a
Are integrally formed with the upper and lower yokes 1 and 2.

By the way, as shown in FIGS. 29 and 30,
The covers 60 and 61 cover the sliding surfaces of the upper and lower yokes 1 and 2 without any gap in the part facing the direction of scattering (arrow F in FIG. 30), and the surface opposite to the direction of scattering scattering. Includes a cover 60, in order to allow the swing angle θ of the upper and lower yokes 1 and 2.
It is desirable to form a gap C ₃ between 61. In this way, spatter is prevented from directly entering the sliding surface, water is prevented from entering the bearing portion of the main shaft 6 from the sliding surface, and the effect of preventing trouble due to bearing rusting is achieved. It has gained.

In FIG. 28, the portion where the ceramic coating layer is formed is shown by a dotted line. The ceramic coating layer is formed on the sliding surface 1a of the upper yoke 1, the sliding surface 2a of the lower yoke 2, the surface 60a of the cover 60, and the surface 61a of the cover 61. The reason why the surfaces 60a and 61a are also coated is to ensure insulation between the upper and lower yokes 1 and 2. A gap 62 is provided between the bearings 10 and 11 so that a short circuit does not occur between the bearings 10 and 11.

A washer 64 having a cover 63 for covering the sliding surface 2a is interposed between the lower yoke 2 and the gun bracket 7, and is fixed to the gun bracket 7 by an engaging member 65 such as a pin or a bolt. . The reason why the ceramic coating is not applied to the facing surface 7a of the gun bracket is that the gun bracket 7 may be deformed due to contact with a jig or the like during welding work, and the frequency of replacement is higher than that of the upper and lower yokes 1 and 2. This is because it is costly to use the washer 64 as a substantial sliding surface. Of course, in some cases, it is possible to form a ceramic coating layer on the facing surface 7a of the gun bracket 7. As a material of the washer 64, a resin material such as an acetal resin or a nylon resin, an oil-impregnated metal having an insulating property, an insulating metal material, a copper material, or the like is suitable.

The operational effects obtained from the sixth embodiment of the present invention having the above structure are as follows. In place of the insulating washer used in the other embodiment, by forming a ceramic coating layer that is an insulating wear resistant layer on each sliding surface 1a, 2a of the upper and lower yokes 1, 2,
The entire width of the rotary shaft portion 3 can be reduced, and the width can be reduced by 6 to 12 mm as compared with the first to fifth embodiments. Therefore, the welding gun can be greatly reduced in size and weight. Also, the ceramic coating layer has very high wear resistance, and the sliding surface of the upper and lower yokes 1
There is no concern about wear of a and 2a. Therefore, the rotating shaft portion 3
The life of is determined only by the life of the bearings 10 and 11, and it is possible to reduce the cost by reducing maintenance work and replacing parts.

By the way, there are other methods for forming an insulating wear-resistant layer on the sliding surfaces 1a, 2a of the upper and lower yokes 1, 2. For example, sliding surfaces 1a, 2a are formed by brazing a metallized ceramic or the like.
It is also possible to join to. As a method for joining the ceramic and the metal, a liquid phase joining method using an active metal or ultrasonic waves,
There are solid-state joining methods such as voltage application and friction welding, and fusion joining methods using laser.

Further, the washer 28 used in the third embodiment can be replaced with a ceramic washer or a metallized ceramic washer, and the same effects as those of the sixth embodiment can be obtained. be able to.

[0076]

According to the present invention, the following effects can be obtained. First, a washer having an insulating property is interposed between the opposing faces of one of the pair of yokes and the gun bracket, and the washer is fixed to one of the opposing faces. A sliding surface is formed by a washer and a facing surface on which the washer is not fixed. Further, by providing a cover that covers the periphery of the sliding surface, scattering does not directly fly to the peripheral end portion of the sliding surface, and moreover, from the peripheral end portion of the substantial sliding surface. By providing a step on the way to the central portion and lengthening the way, it is possible to prevent scattering from entering the sliding surface.

When the washer is composed of a pair of washer pieces, at least one of which has an insulating property, and each washer piece is fixed to the adjoining facing surfaces, the contact surfaces of the pair of washer pieces are , A substantial sliding surface in the opening / closing operation of the pair of yokes. In addition, the insulation between the opposing surfaces with the washer interposed is secured. And
A cover is provided at the peripheral end portions of the pair of washers to cover the peripheral end portions of the pair of washers so that the sliding surface end portions of the washers are not exposed, which leads to damage of the rotary shaft portion 3. Wear of the sliding surface can be prevented. Further, wear due to long-term use occurs only in the pair of washer pieces, and the pair of yokes and the gun bracket, which are the main components of the welding gun, are not worn, and the regular shape can always be maintained. it can. Therefore, when the rotating shaft portion is loosened, it can be returned to a state similar to a new one by only replacing the pair of washer pieces.

By the way, when the cover is constructed by forming a projection for covering the other peripheral end portion on at least one peripheral end portion of the pair of washer pieces, it is substantially constituted by the pair of washer pieces. It is possible to cover the end of the smooth sliding surface with the washer itself. Further, by devising the shape of the protrusion, the pair of washer pieces can be made into the same component, and the increase in the number of components can be prevented.

At least one of the pair of washers has a multi-layer structure including an elastic material layer having an insulating property and a flame retardant property, and the other is provided on the outer peripheral portion of the elastic material layer having an insulating property and a flame retardant property. By integrally forming a cover that covers the outer peripheral portion of the washer, the cover is elastically deformed so that it does not interfere with other parts when the rotary shaft is assembled, so that the assembly direction is not restricted and It is possible to improve the sex. Moreover, the presence of the elastic material layer ensures the insulating property of the washer piece.

Further, in the case where a groove that opens at the outer peripheral portion of the washer is formed on the contact surface between the pair of washers while avoiding the spindle hole provided in the washer, the contact between the pair of washer pieces is made. The surface serves as a sliding surface in the opening / closing operation of the pair of yokes, and catches inward dispersion from the peripheral ends of the sliding surfaces by the groove, and further positively discharges the dispersion out of the groove. can do. Therefore, there is no possibility that the dust will penetrate into the deep portion of the sliding surface and damage the main shaft or the like. Further, wear due to long-term use occurs only in the pair of washer pieces, and it is possible to restore a state similar to a new article by only replacing the washer pieces.

Further, the pair of yokes are coaxially supported and sandwiched by the gun brackets, and an insulating wear-resistant layer is formed on the sliding surfaces of the pair of yokes to insulate the sliding surfaces themselves. And wear resistance. Therefore, it is not necessary to interpose an insulating member on the sliding surfaces of the pair of yokes, and the width can be reduced. Therefore, it contributes greatly to the reduction in size and weight of the welding gun. Further, by integrally forming the cover that covers the end portion of the sliding surface on the pair of yokes, the scattering is prevented from directly flying to the peripheral end portion of the sliding surface, and It is possible to prevent intrusion of dust. Therefore, it is possible to reduce costs by reducing maintenance work and replacing parts.

In the conventional method of shutting off the rotating shaft portion from the scattering by the rubber or metal cover,
If the rubber or metal cover loses its blocking function, it is difficult to prevent the dust from adhering to the rotary shaft and causing a problem caused by entering the rotary shaft.
In the present invention, since the rotating shaft portion itself has a closed structure, even if the rotating shaft portion is placed under the condition that the scattering is scattered, no trouble occurs in the rotating shaft portion and reliability is improved. It is possible to maintain.

Further, the insulating member or washer can be easily attached / detached, and at the same time as exchanging the insulating member, the dust remaining on the surface layer of the rotary shaft can be removed to maintain the function of the welding gun for a long time. You can As described above, in the resistance welding apparatus of the present invention, the welding gun is disassembled and cleaned,
Maintenance such as parts replacement can be greatly saved, and the replacement work of the insulating member is easy.Therefore, due to the production schedule, there is no need to perform welding work unavoidably while the equipment is defective, and It is possible to stabilize the welding quality. Further, since the maintenance cost can be reduced, the cost of the single component welded by the resistance welding apparatus of the present invention can be reduced.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a rotating shaft portion of a welding gun of a resistance welding device according to a first embodiment of the present invention.

FIG. 2 is a unitary view showing an example of the insulating member shown in FIG.

3A and 3B are schematic views showing an example of a cross-sectional shape of the insulating member shown in FIG.

FIG. 4 is a unitary view showing another example of the insulating member shown in FIG.

5 is an enlarged view showing an end shape of the insulating member divided into two shown in FIG.

FIG. 6 is a schematic view showing another fixing structure of an insulating member divided into two parts.

FIG. 7 is a cross-sectional view showing a rotating shaft portion of a welding gun of a resistance welding device according to a second embodiment of the present invention.

FIG. 8 is a cross-sectional view showing a rotating shaft portion of a welding gun of a resistance welding device according to a third embodiment of the present invention.

9 is an exploded view of the rotating shaft portion shown in FIG.

FIG. 10 is a unitary view of a pair of washer pieces according to a third embodiment of the present invention.

11 is a modification of the pair of washer pieces shown in FIG.

12 is a further modification of the pair of washer pieces shown in FIG.

13 is a cross-sectional view of the rotating shaft portion shown in FIG.

14 is a partial cross-sectional view showing peripheral end portions of sliding surfaces of the pair of washer pieces shown in FIG.

FIG. 15 is a partial cross-sectional view showing a modified example of the peripheral ends of the sliding surfaces of a pair of washer pieces.

FIG. 16 is a partial cross-sectional view showing a modified example of the peripheral ends of the sliding surfaces of a pair of washer pieces.

FIG. 17 is a partial cross-sectional view showing a modified example of the peripheral end portions of the sliding surfaces of the pair of washer pieces.

FIG. 18 is a partial cross-sectional view showing a modified example of the peripheral end portions of the sliding surfaces of the pair of washer pieces.

19 is a perspective view of the circular ring shown in FIG. 18. FIG.

20 is an enlarged view showing an end shape of the circular ring shown in FIG.

FIG. 21 is a partial cross-sectional view showing a pair of washer pieces according to a fourth embodiment of the present invention.

22 is a partial cross-sectional view showing a modified example of the cover shown in FIG.

FIG. 23 is a unitary view showing a pair of washer pieces according to a fifth embodiment of the present invention.

FIG. 24 is a view showing a modified example of the groove formed on the sliding surface of the washer piece shown in FIG. 23.

FIG. 25 is a view showing a modified example of the groove formed on the sliding surface of the washer piece shown in FIG. 23.

FIG. 26 is a view showing a modified example of the groove formed on the sliding surface of the washer piece shown in FIG. 23.

FIG. 27 is a view showing a modified example of the groove formed on the sliding surface of the washer piece shown in FIG. 23.

FIG. 28 is a cross-sectional view showing the rotating shaft portion of the welding gun of the resistance welding device according to the sixth embodiment of the present invention.

29 is a front view of the rotating shaft portion shown in FIG. 28. FIG.

30 is a cross-sectional view taken along the line EE in FIG.

FIG. 31 is a side view showing a welding gun of the resistance welding device.

32 is a vertical cross-sectional view taken along the line AA of FIG.

FIG. 33 is a schematic diagram showing a cover of a rotary shaft portion of conventional upper and lower yokes.

FIG. 34 is a schematic view showing a cover of a rotary shaft portion of conventional upper and lower yokes.

[Explanation of symbols]

 1 Upper yoke 2 Lower yoke 3 Rotating shaft 6 Spindle 7 Gun bracket 8 Insulating washer 17 Insulating member 28 Washer 28a Washer piece 28b Washer piece 33a Protrusion 33b Protrusion

Claims (6)

[Claims] 1. A pair of yokes are coaxially supported and sandwiched by a gun bracket, and the opposing surfaces between the pair of yokes and the opposing surface between one of the pair of yokes and the gun bracket include: Resistance welding, characterized in that a washer having an insulating property is interposed and the washer is fixed to one of the facing surfaces facing each other, and a cover is provided to cover substantially the circumference of the sliding surface when the pair of yokes is opened and closed. apparatus. 2. The resistance welding device according to claim 1, wherein the washer comprises a pair of washer pieces at least one of which has an insulating property, and each washer piece is fixed to an adjacent facing surface. 3. The resistance welding device according to claim 2, wherein the cover has a protrusion formed on at least one peripheral end portion of the pair of washer pieces to cover the other peripheral end portion. . 4. At least one of the pair of washer pieces has a multilayer structure including an elastic material layer having an insulating property and a flame retardant property, and the other is provided on an outer peripheral portion of the elastic material layer having an insulating property and a flame retardant property. The resistance welding apparatus according to claim 2, wherein a cover that covers an outer peripheral portion of the washer is integrally formed. 5. A pair of yokes are pivotally supported by a main shaft and are sandwiched by a gun bracket, and at least on a facing surface between the pair of yokes and a facing surface between one of the pair of yokes and the gun bracket. One pair of washer pieces each having an insulating property is interposed and fixed to the adjoining opposing surfaces, and the outer peripheral portion of the washer piece is avoided at the contact surface between the washer pieces, avoiding the spindle hole provided in the washer. A resistance welding device characterized in that a groove opening at is formed. 6. A pair of yokes are coaxially supported and sandwiched by gun brackets, an insulating wear-resistant layer is formed on the sliding surfaces of the pair of yokes, and the ends of the sliding surfaces are covered. A resistance welding device having a cover.