JPH08323484A - Multipoint projection welding equipment - Google Patents

Abstract

PURPOSE: To provide multipoint projection welding equipment capable of suppressing the generation of splash as far as possible, in welding a member to be joined with the use of plural projections. CONSTITUTION: With plural projections 3A, 3B, 3C provided in one of a pair of joining members 21, 22, a pair of members to be joined are abutted on each other through these projections; and also, with both of these members to be joined held and pressurized between a pair of electrodes 23, 24, the electric current is made to flow between these members. The contact parts of each projection and with these projections of the members to be joined are thereby melted so that both members to be joined are welded, as so structured in the subject welding equipment used for multipoint projection; one electrode is provided so that it is possible to oscillate relatively against other electrodes.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a projection welding apparatus, and more particularly, to a multi-point projection apparatus adapted to perform welding using a plurality of projections.

[0002]

2. Description of the Related Art Conventionally, as a method of joining members to be welded, as shown in FIGS.
A projection 3 (projection) is provided on one of the two 2, and as shown in FIG. 6, a pair of members 1 and 2 to be joined are abutted via these projections 3 and both members 1 and 2 are joined together. 2 is sandwiched between a pair of electrodes 4 and 5 and pressed to supply electricity between the members 1 and 2 to be joined, so that the pressing force and current applied to both members 1 and 2 to be joined are applied to the contact portion with the projection. Projection welding is known in which the projections 3 and the contact portions thereof are melted and welded by concentrating them.

On the other hand, for the purpose of ensuring welding strength,
As shown in FIGS. 5 and 6, the pair of members to be joined 1 and 2 are joined together.
A plurality of projections 3 are provided on one of the members 1 to be joined, and the plurality of projections 3 are melted so that both the members 1 and 2 to be joined are welded at multiple points. ing.

In order to perform such multi-point projection welding, conventionally, a welding device 6 as shown in FIG. 7 has been used.

This multi-point projection welding apparatus 6 is
A base 7 to which a fixed electrode 4 to which the one member to be joined 1 is attached, another movable electrode 5 are attached, and an elevating / lowering body 8 that can be moved toward and away from the fixed electrode 4, Along with the movement of the lifting body 8, a pressurizing means 9 for applying a pressing force to the pair of members to be joined 1 and 2 positioned between the electrodes 4 and 5, the base body 7 and the lifting body 8 And a power cable 10 that supplies power to both electrodes 4 and 5 via the base 7 and the lifting body 8.

A fluid pressure cylinder using air pressure or hydraulic pressure is used as the pressurizing means 9, and the movable electrode 5 maintains a fixed posture with respect to the fixed electrode 4 by the pressurizing means 9. However, they can be moved closer to each other.

In the multi-point projection welding apparatus 6, the one member 1 to be joined is placed on the fixed electrode 4.
The plurality of projections 3 are mounted so as to face the movable electrode 5, and the movable electrode 5 is mounted on the one member 1 to be joined in a state where the other member 2 to be joined is aligned. Is moved toward the other member 2 to be joined by the pressing means 9 and brought into contact with the other member 2 to be joined under a predetermined pressure, whereby the movable electrode 5 and the fixed electrode 4 are connected. The two members to be joined 1 and 2 are sandwiched by the above, and a predetermined pressure is applied between the members to be joined 1 and 2.

Further, after the two members to be joined 1 and 2 are sandwiched by a predetermined pressing force, they are energized between the electrodes 4 and 5 to be provided on the one member to be joined 1. The plurality of projections 3 that are present and the portion of the other member to be joined 2 that is in contact with the projection 3 are melted, and these members to be joined 1 and 2 are welded.

[0009]

The conventional multi-point projection welding apparatus 6 as described above, however, has the following problems to be improved.

That is, in order to obtain uniform welding strength in each of the plurality of projections 3, it is necessary to keep the contact pressure between each projection 3 and the other member 2 to be joined constant. However, in the above-mentioned conventional multi-point projection welding apparatus 6, since the fixed electrode 4 and the movable electrode 5 are moved relative to each other while keeping their relative postures constant, both electrodes 4 and
The relative postures of both members to be joined 1 and 2 sandwiched by 5 are also kept constant by the relative postures of the electrodes 4 and 5, and as a result, one member to be joined 1 is joined.
When the heights of the projections 3 vary due to variations in molding, the contact pressure between the projections 3 and the other member 2 to be joined becomes non-uniform.

For example, as shown in FIG. 8 in an unloaded state, when the conventional multi-point projection welding apparatus 6 applies a pressure to three projections 3A to 3C having different heights, the movable electrode 5 is initially After the projection 3A is brought into contact with the highest projection 3A and is deformed by pressing, the projections 3B and 3C are brought into contact with each other and the projections 3B and 3C are deformed by pressing,
These projections 3A to 3C have substantially uniform heights, as shown as distributed loads in FIG.

Here, most of the applied pressure applied through the movable electrode 5 is supported by the projection 3A which is deformed first, so that a sufficient contact pressure can be obtained in this high projection 3A.
In the remaining projections 3B and 3C, sufficient contact pressure cannot be obtained.

Then, each projection 3
If the contact pressure between the member to be joined and the other member to be joined 2 is non-uniform, the current flowing through each projection 3 will vary, not only will the welding conditions in each projection 3 be non-uniform, but also the projection 3 Depending on the degree of height variation, splash may occur at a portion where only low contact pressure is obtained.

When the splash is generated in this way, when the splashes are separated from the joined members 1 and 2 after the joined members 1 and 2 are assembled to the equipment, the splashes move in the equipment and cause abnormal noise or noise. It is expected that the above causes or may affect the function of the device, and therefore a countermeasure is demanded.

For example, when the device is a rotating device, when the splash is caught in the bearing or the like, a loss phase is given to the bearing itself and the rotating shaft supported by the bearing, thereby increasing the rotational resistance and improper rotation. Will be invited.

The present invention has been made in view of the above-mentioned conventional problems, and in performing welding of members to be joined by using a plurality of projections, multi-point projection welding capable of suppressing the occurrence of splash as much as possible. The purpose is to provide a device.

[0017]

In order to achieve the above-mentioned object, a multi-point projection welding apparatus according to claim 1 of the present invention is provided with a plurality of projections on one of a pair of members to be joined. By abutting a pair of members to be joined together through projection, and energizing between the members to be joined while sandwiching both the members to be joined by a pair of electrodes, each projection of the members to be joined and these A welding device used for a multi-point projection in which a contact portion with a projection of is melted, and both members to be welded are welded to each other, and one of the electrodes is relative to another electrode. It is characterized in that it is swingably provided.

According to a second aspect of the present invention, there is provided the multi-point projection welding apparatus according to the first aspect, wherein the swingably provided electrodes are provided with the same number of pressurizing means as the projections. In addition, these pressurizing means are respectively positioned on the straight line connecting the center of the one member to be joined and each projection.

Further, a multi-point projection welding apparatus according to a third aspect of the present invention is characterized in that, in the first or second aspect, the three projections are provided.

[0020]

According to the multi-point projection welding apparatus of the first aspect of the present invention, when one pair of electrodes is sandwiched by a pair of electrodes, one electrode can swing with respect to another electrode. Therefore, even if the relative postures of the two members to be joined are changed so that a stable contact state can be obtained, the swinging motion of the swingable electrode follows the above-described posture change of the members to be joined. The attitude of the electrodes changes.

Therefore, even when the relative postures of the two members to be joined are changed due to the variations in the heights of the plurality of projections provided on the one member to be joined, The attitude of the other member to be joined with respect to the one member to be joined is adjusted in accordance with the height difference, and the contact pressure between the other member to be joined and each projection is made uniform.

Further, according to the multi-point projection welding apparatus of the second aspect of the present invention, the same number of pressing means as the number of projections are attached to the swingable electrode, and these pressing means are provided. However, by being positioned respectively on the straight line connecting the center of the one member to be joined and each projection, the pressing force on the other member to be joined efficiently acts in the vicinity of the contact portion with each projection. To be made. As a result, the other member to be joined and each projection are brought into contact with each other quickly and reliably, and the contact pressure is made uniform.

Further, according to the multi-point projection welding apparatus of the third aspect of the present invention, the number of projections used for welding is three, so that the number of contact points between the two joining members is three, and during welding. The relative posture of the two can be stabilized.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. In these figures, reference numeral 20 is
1 shows a multi-point projection welding apparatus according to this embodiment. And, in the present embodiment, as the members to be joined,
A yoke 21, which is a component of the stepping motor, and a disk-shaped flange 22 joined to the end surface of the yoke 21.
The three projections 3A to 3C (see FIG. 2) provided on the end surface of the yoke 21 are used to weld the yoke 21 and the flange 22. Yoke 21 and flange 22
And a pair of electrodes 23 and 24 for passing a welding current between them, and one of the pair of electrodes 23 and 24 can be swung with respect to the other electrode. It has a schematic configuration.

More specifically, in the present embodiment, each of the electrodes 23 and 24 is formed in a cylindrical shape with a bottom, the opening end faces of which are smooth, and the opening end faces face each other. Are arranged vertically so as to be substantially coaxial with each other, one electrode 23 of which is detachably fixed to a base 25 attached to the apparatus by a bolt 26, and the yoke 21 is mounted. Fixed electrode,
The other electrode 24 is a movable electrode that is moved closer to and away from the fixed electrode 23 from above.

The movable electrode 24 has a lifting mechanism 27 for moving the movable electrode 24 in the above-described direction and a swing mechanism 2 for moving the movable electrode 24.
It is swingably supported via 8. The lifting mechanism 2
In the present embodiment, 7 is a fluid pressure cylinder using air pressure or hydraulic pressure, and the swing mechanism 28 is attached to the tip of the movable rod 27a of this fluid pressure cylinder.

The swinging mechanism 28 includes the movable rod 27.
a base plate 29 integrally fixed to the tip of a, and a space below the base plate 29,
The movable electrode 24 is attached between the electrode holding plate 31 to which the bolt 30 is detachably attached and the base plate 29 and the electrode holding plate 31 so as to regulate the maximum distance between the electrodes and the maximum distance between the electrodes. Guide rods 3 that lock both at
2 and a spring 33 that is arranged around each of these guide rods 32 and that springs the electrode holding plate 31 in a direction away from the base plate 29. In the present embodiment, these springs are used. 33 is a pressurizing means for pressing the movable electrode 24.

On the other hand, each of the guide rods 32 has one end (upper end in FIG. 1) fixed to the base plate 29, and the other end (lower end in FIG. 1). The electrode holding plate 31 is slidably pierced in the vertical direction, and an appropriately shaped locking step portion (not shown) provided at the other end is engaged with the electrode holding plate 31. As a result, the electrode holding plate 31 is prevented from coming off downward.

In the present embodiment, each of the guide rods 32 has the yoke 21 as shown in FIG.
Is located on an extension line connecting the three projections 3A to 3C provided in the center of the yoke 21 with respect to the base plate 29,
For example, each guide rod 3 of the base plate 29
By making the inner surface of the hole through which 2 penetrates into a drum shape, it can be swung within a range of a predetermined angle.
The yoke 21 mounted on the
Positioning means for positioning A to 3C with respect to each guide rod 32 of the swing mechanism 28 are provided so as to have the above-mentioned positional relationship.

The configuration of the positioning means is appropriately set according to the shape of the members to be joined such as the yoke 21 and the like.

Since the movable electrode 24 is supported by the swing mechanism 28, the movable electrode 2
When the opening end face of No. 4 is brought into contact with the surface inclined with respect to the opening end face of the fixed electrode 23, each of the guide rods 32
The movable electrode 24 is moved to the electrode holding plate 31 by the tilting motion of the
With this, the movable electrode 24 is tilted so that the opening end surface of the movable electrode 24 can smoothly follow the above-mentioned inclined surface.

Next, the operation of the multi-point projection welding apparatus 20 of the present embodiment thus constructed will be described. First, prior to the welding operation, the movable electrode 24 is moved by the lifting mechanism 27 together with the swing mechanism 28 to the fixed electrode 23.
The fixed electrode 23 is placed at a position separated from
2 so that the projections 3A to 3C provided on the end surface of the yoke 21 face the movable electrode 24, and these projections 3A to 3B are moved relative to the guide rods 32 of the swing mechanism 28 with respect to the guide rods 32 of FIG. After mounting while positioning so as to have the relationship shown in FIG.
The flange 22 is placed on the end face of the.

By operating the elevating mechanism 27, the movable electrode 24 is lowered toward the fixed electrode 23, and the open end face of the movable electrode 24 is brought into contact with the upper face of the flange 22 on the yoke 21.

As a result, when the lowering operation of the elevating mechanism 27 is further continued, since the movable electrode 24 is in contact with the flange 22, the movable electrode 24 and the movable electrode 24 are fixed. The descending of the electrode holding plate 31 being stopped is stopped, but by the sliding of each of these guide rods 32 and the electrode holding plate 31,
The base plate 29 is further lowered toward the electrode holding plate 31 (see FIG. 3).

Due to the relative movement of the base plate 29 with respect to the electrode holding plate 31, the plurality of springs 33 interposed therebetween are compressed and deformed, and the pressing force corresponding to the amount of deformation causes the electrode holding plate 31 to hold. It is transmitted to the flange 22 via the plate 31 and the movable electrode 24, and also acts as a contact pressure on the contact portion between the flange 22 and each of the projections 3A to 3C.

The elevating mechanism 27 continues to lower the base plate 29 until the contact pressure between the flange 22 and the projections 3A to 3C reaches a predetermined pressure, and the contact pressure reaches a predetermined value. At that time, the lowering operation of the elevating mechanism 27 is stopped, and then a welding current is caused to flow between the electrodes 3 and 24 by the power cable 34 connected to the base plate 29 and the base 25.

At this time, the energization between the base plate 29 and the electrode holding plate 31 is carried out at three places by the energizing cable 35 fixed by the bolts 36.

As a result, each projection 3
The projections 3A to 3C and the flange 22 at the respective contact portions are melted by the pressure and welding current concentration at the contact portions between the A to 3C and the flange 22. Since the pressurizing force of the flange 22 is constantly acting, the flange 22 gradually moves toward the yoke 21 with the above-mentioned melting.
Is moved to.

Then, after the projections 3A to 3C are completely melted and the flange 22 is brought into surface contact with the end surface of the yoke 21, the supply of the welding current is stopped and the yoke 21 and the flange 22 are naturally cooled. As a result, the yoke 21 and the flange 22 are welded.

In such a welding operation, when the projection amounts of the plurality of projections 3A to 3C are varied, the virtual plane passing through the tips of the projections 3A to 3C is inclined with respect to the end face of the yoke 21. However, in order to make the contact pressure between the projections 3A to 3C and the flange 22 uniform, in order to make the contact pressure between the yoke 21 and the flange 22 uniform, the flange 22 is moved along the above-mentioned virtual surface. In this embodiment, such attitude control of the flange 22 is realized in the process of pressing the flange 22.

That is, the movable electrode 2 by the lifting mechanism 27
This movable electrode 24 is moved to the flange 22
When the flange 22 is brought into contact with the movable electrode 24, the flange 22 is swung about a contact portion with a projection (for example, 3A) having the maximum protrusion amount and brought into surface contact with the opening end face of the movable electrode 24. In this state, the flange 2
2 is kept parallel to the end face of the yoke 21 while being kept in contact with the projection 3A having the maximum amount of projection and separated from the many projections 3B and 3C.

When the movable electrode 24 is further lowered, the guide rods 32 are moved to the base plate 29.
Since it is slidable and tiltable with respect to each other, the electrode holding plate 31 and the base plate 29 are brought close to each other, and the spring 33 is compressed and deformed by the approach of the both plates 29, 31. The flange 22 is pressed at a plurality of points by the elastic force, but the part of the flange 22 other than the contact point with the projection 3A having the maximum projection amount is supported against the pressing force of the spring 33 described above. Since the movable electrode 24 is absent, the movable electrode 24 is swung together with the flange 22 toward the yoke 21 side around the contact point with the projection 3A having the maximum protrusion amount.

In this swinging operation, the portion of the flange 22 in the swinging state is the other two projections 3B and 3C.
And continues until the above-mentioned pressing force is supported, whereby the flange 22 is inclined along the above-mentioned virtual surface.

When the movable electrode 24 and the electrode holding plate 31 are tilted in this manner, the spring 3 for generating a pressing force for the projection 3A having the maximum protrusion amount.
The amount of deformation of the remaining springs 33 is slightly smaller than the amount of deformation of the springs 3, and the pressing force of these springs 33 varies, and the contact of the flange 22 with each projection 3A to 3C is made. Although the pressure also varies, the difference in contact pressure is very small compared to the pressure required for welding, and can be ignored within the range of welding conditions.

In particular, by making the spring constant of the spring 33 as small as possible, it is possible to further reduce the influence of the difference in contact pressure at the initial stage of pressurization on the welding conditions.

Therefore, in the present embodiment, even when the heights of the plurality of projections 3A to 3C are uneven, the flange 22 is inclined in accordance with the height difference between the projections 3A to 3C, and the flange 22 is used for each projection. 3A to 3C are brought into contact with each other under a substantially uniform contact pressure (this state is shown by a uniform load in FIG. 8),
Further lowering of the base plate 29 causes each spring 33 to be uniformly compressed and deformed, so that a uniform predetermined pressing force can be obtained in each projection 3A to 3C and a uniform contact portion with each projection 3A to 3C. Welding conditions are realized and as a result,
Generation of splash is suppressed.

Further, in this embodiment, the flange 22
Since the spring 33 as a pressurizing means is positioned on the extension line connecting the projections 3A to 3C and the center of the yoke 21, the pressing force is applied to the contact portion between the projections 3A to 3C and the flange 22. The welding force is applied in the vicinity, so that the pressing force at each of the above-mentioned contact portions is surely secured, and from this point as well, the above-mentioned welding conditions are surely obtained.

Further, in this embodiment, the number of projections 3 is three, and the number of springs 33 as pressing means is also three.
Since it becomes point support, unnecessary movement of the flange 22 at the time of welding is suppressed, and stable welding becomes possible.

On the other hand, the movable portion for tilting the flange 22 to follow the virtual plane passing through the tips of the projections 3A to 3C is the movable electrode 24 and the electrode holding plate 3.
Since it is an assembly of relatively lightweight members such as the one, the plurality of guide rods 32, and the plurality of springs 33, the inertial mass thereof is small, and as a result, the above-described tilting operation of the flange 22 is quickly performed.

The shapes and dimensions of the constituent members shown in the above embodiment are merely examples, and can be variously changed based on the type and shape of the members to be joined, design requirements, and the like.

For example, in the above-described embodiment, an example in which the pressing means is constituted by the three guide rods 32 and the springs 33 arranged around the guide rods 32 has been shown. It can be arbitrarily changed according to the number of projections 3 provided in the.

Further, the pressurizing means may be constituted by a fluid pressure cylinder using air pressure or hydraulic pressure. Further, in the case of such a configuration, it is necessary to swingably connect the connection portion between the fluid pressure cylinder and the base plate 29 or the electrode holding plate 31 with a universal joint or the like.

On the other hand, by changing the pressing means as described above,
Although the form of pressurization of the members to be joined changes, the form of pressurization in the case where the pressurizing means is constituted by springs and the spring constants of these are changed and in the case where the pressurizing means is constituted by the air cylinder are The change situation will be described with reference to FIG.

In FIG. 4, a curve a shows a change in the pressing force during welding when a spring having a small spring constant is used, and a curve b shows a change in the pressing force when the spring constant of the spring is increased. A curve c shows a change in pressure force when an air cylinder is used.

As shown in this figure, in a spring having a small spring constant, the pressing force hardly changes during the welding process, and the stable pressing force is maintained. As a result, the welding current also changes as shown in FIG. Stable supply as shown by the solid line. Therefore, it is possible to perform welding that is good and that suppresses the occurrence of splash.

Further, when a spring having a large spring constant is used, a phenomenon occurs in which the pressing force decreases as the welding progresses. However, since the amount of decrease is small, there is almost no effect on the welding current. I can't.

Further, in the case of using the air cylinder, the welding pressure is relatively greatly reduced during welding, and accordingly, the welding current is also reduced as shown by the curve d in FIG. The condition tends to be slightly worse.

In this way, when the spring is used as the pressurizing means, the change in the pressing force is suppressed to a small extent because the compression amount of the spring is sufficiently larger than the height of the projection, and This is because even if the compression amount changes in accordance with the change in the projection height, the change amount of the compression amount described above is small with respect to the total compression amount to obtain the predetermined pressurization amount.

Further, when the air cylinder is used, the pressing force is reduced because the space of the air cylinder when it is mounted on the equipment is restricted and the volume of the air cylinder is suppressed to be small. This is because the pressure change in the air cylinder is large, and as a result, the pressure drop in the air cylinder with respect to the movement of the piston due to the change in the projection height during welding is large.

In order to prevent a decrease in the applied pressure when using such an air cylinder, it is necessary to perform control such that the pressure of the air cylinder is always kept constant.

Further, in the above-described embodiment, the example in which the movable electrode 24 and the swing mechanism 28 are connected via the electrode holding plate 31 is shown, but the movable electrode 24 is directly attached to the swing mechanism 28. Good.

[0062]

As described above, according to the first aspect of the present invention.
According to the multi-point projection welding apparatus according to, when performing projection welding using a plurality of projections, even if there is a variation in the height of these projections, the joined members to be contacted with each of these projections, By swinging the electrodes that press the members to be joined, the electrodes can be tilted in accordance with the height difference of the plurality of projections and can be brought into contact with each projection under a substantially uniform contact pressure.

As a result, uniform welding conditions can be realized at the respective contact portions between the member to be joined and the projections, and the occurrence of splash can be suppressed well.

According to the multi-point projection welding apparatus of the second aspect of the present invention, the pressing means for the members to be joined is a straight line connecting each projection and the center of the member to be joined on which the projection is provided. By positioning it above, the pressing force is made to act as close as possible to the contact area between each projection and the member to be joined, and this makes it possible to reliably apply the pressing force to each of the contact areas mentioned above, and to the set value. It is possible to easily realize suitable welding conditions, and also from this point, good splash prevention can be performed, and uniform welding can be performed.

Further, according to the multi-point projection welding apparatus according to the third aspect of the present invention, since the number of the projections 3 is three, the members to be joined by the projection are supported at three points and the objects to be welded at the time of welding. Unnecessary movement of the joining member can be suppressed and stable welding can be performed.

[Brief description of drawings]

FIG. 1 is a partial sectional front view showing a state before starting welding, according to an embodiment of the present invention.

FIG. 2 shows an embodiment of the present invention and is a plan view of an essential part for showing the positional relationship between the projection and the pressing means.

FIG. 3 shows an embodiment of the present invention and is a partial sectional front view showing a welded state.

FIG. 4 is a diagram showing an embodiment of the present invention and is a diagram showing changes in welding force and welding current during welding when the pressurizing means is changed.

FIG. 5 is a vertical cross-sectional view showing an example of members to be joined to which multi-point projection welding is applied.

FIG. 6 is a vertical cross-sectional view of a main part of a projection welding apparatus for explaining an outline of multi-point projection welding.

FIG. 7 shows a conventional multi-point projection welding apparatus,
It is a partial cross-section front view.

FIG. 8 is a diagram showing an example of a change in height of each projection due to a difference in pressure type in multi-point projection welding.

[Explanation of symbols]

 3 (3A-3B) Projection 20 Multi-point projection welding device 21 Yoke (joined member) 22 Flange (joined member) 23 Fixed electrode 24 Movable electrode 28 Swing mechanism 33 Spring (pressurizing means) 35 Energizing cable 36 Bolt

Claims (3)

[Claims] 1. A plurality of projections (3A, 3B, 3C) are provided on one of a pair of members to be joined (21, 22), and the pair of members to be joined are abutted through these projections, and both of these members are joined together. The members to be joined are sandwiched by a pair of electrodes (23, 24) and pressed to energize between the members to be joined, thereby melting each projection of the member to be joined and the contact portion with these projections. A welding device used for a multi-point projection for welding members to be joined, wherein one of the electrodes is provided so as to be capable of swinging relative to the other electrode. Characteristic multi-point projection welding equipment. 2. The swingable electrode (24)
The same number of pressing means (3) as the number of projections.
3) is attached, and these pressurizing means are respectively positioned on a straight line connecting the center of the one member to be joined and each projection (3A, 3B, 3C). The multi-point projection welding apparatus according to claim 1. 3. The projection (3A / 3B / 3)
3. The multi-point projection welding apparatus according to claim 1, wherein three C) are provided.