JP2887860B2 - Projection welding method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a projection welding method and, more particularly, to a welding method for welding a welding material and a material to be welded. The present invention relates to a projection welding method for performing resistance welding by concentrating a welding current and a welding pressure.

[0002]

2. Description of the Related Art In general, a projection welding method includes:
By processing the projection on the welding material and concentrating the welding current and welding pressure between the projection and the material to be welded, and obtaining thermal equilibrium, the welding material and the material to be welded can be welded to each other with a small amount of deformation and high accuracy. It is possible to do. In this projection welding method, in order to ensure sufficient welding strength, when performing welding, for a predetermined time,
It is necessary to supply a required welding current.

However, in this welding method, a welding material having a long shape in a welding pressure direction is welded to a material to be welded, and if a sufficient welding strength is to be ensured, heat generated by Joule heat and welding pressure are used. A large thermal deformation is generated at the welding material portion in contact with the electrode, that is, at the tip of the welding material.

FIG. 6 is a diagram for explaining a conventional projection welding method. A conventional projection welding method will be described below with reference to FIG. In FIG. 6, 1 is a welding material, 2 is a material to be welded, 3 is an upper electrode, 4 is a lower electrode, and 11 is a projection.

In the prior art shown in FIG. 6, as can be seen from the side view shown in FIG. 6A and the bottom view of the welding material 1 shown in FIG. The welding material 2 is welded to the bottom of the welding material 1 via a projection 11 provided in a substantially circular ring shape. In the method according to the prior art, a pressing force is applied between the welding material 1 and the material 2 to be welded by the electrodes 3 and 4 provided on the upper portion of the welding material 1 and the lower portion of the material 2 to be welded. To weld the welding material 1 and the material 2 to be welded.

[0006] In the welding method according to the prior art shown in the drawings, an electrode 3 and a welding material 1 are welded to each other.
4, when a pressing force is applied between the welding material 1 and the workpiece 2 and a welding current is applied, the welding current from the electrode 3 becomes
It flows to the electrode 4 via the welding material 1, the projection 11, and the workpiece 2. Then, the welding current flows intensively in the portion of the projection 11 and generates Joule heat in this portion to soften and melt the projection 11. As a result, the projection 11 is crushed by the pressing force between the welding material 1 and the material to be welded 2 applied by the electrodes 3 and 4, and the respective welding surfaces of the welding material 1 and the material to be welded 2 adhere to each other. Then, at the position of the projection 11, the welding material 1 and the material to be welded 2 are mutually welded.

In the projection welding method according to the prior art described above, as shown in FIG. 6, a welding pressure is applied from a welding material portion in contact with the upper electrode 3, that is, a welding material tip portion, and the welding material is applied. 1, the welding current also flows through the inside of the welding material 1 from the tip of the welding material and flows to the projection 11. For this reason, in the projection welding method according to the prior art, Joule heat is generated due to electric resistance between the upper electrode 3 and the welding material 1 at the tip of the welding material and softens, and this portion is deformed by the action of welding pressure. Cause a malfunction.

[0008]

SUMMARY OF THE INVENTION The above prior art relates to both securing a sufficient welding strength and preventing the occurrence of thermal deformation when welding a welding material having a long shape in the welding pressure direction to a material to be welded. Is not taken into account.

[0009] For this reason, in the prior art, in order to ensure a sufficient welding strength, when a required welding current is passed for a predetermined time, the Joule heat and the welding pressure due to the current flowing through the welding material itself are used. There is a problem that a large thermal deformation is generated at the welding material portion in contact with the electrode, that is, at the tip of the welding material. As a result, in the conventional technique, the processing of the front end of the welding material has to be post-processed,
Further, depending on the size or shape of the welding material and the material to be welded, it is difficult to perform post-processing, and this causes a problem that productivity is reduced accordingly.

On the other hand, the prior art, on the contrary, has a problem that if the heat input amount, that is, the time for flowing the welding current is reduced so as not to cause thermal deformation, sufficient welding strength cannot be obtained. Have.

[0011] Further, the above-mentioned conventional technique is intended to weld a welding material having a long shape in the welding pressure direction to a workpiece.
Due to the variation of the welding current flow inside the material of the welding material and the variation in impedance, it is not possible to flow a uniform welding current over the entire area of the projection, so that uniform welding quality cannot be guaranteed. In addition to the above, there is a problem that the size in the welding pressure direction is long, and buckling or the like occurs with respect to the welding material of the hollow circular pipe, so that the welding itself may not be performed. .

Further, in the prior art, since the projection is formed in a continuous ring shape, a closed space surrounded by the welding material and the material to be welded and the projection is formed, and the air in this space is released at the time of welding. There is a problem that the projection that rapidly expands and softens and melts is damaged, and it is difficult to perform high-precision welding because the welding material is welded in an inclined state with respect to the material to be welded. doing.

An object of the present invention is to solve the above-mentioned problems of the prior art, and to provide a projection welding method for welding a welding material having a long shape in a welding pressure direction to a material to be welded. It is an object of the present invention to provide a projection welding method which can surely prevent the welding and can secure sufficient welding strength and guarantee high quality welding.

Another object of the present invention is to provide a projection welding method in which the positioning of the welding material and the material to be welded is easy and the welding material can be welded with high precision without inclining the material to be welded. It is in.

[0015]

SUMMARY OF THE INVENTION According to the present invention, the object is to provide a method for welding a welding material attached to two opposed electrodes.
The contact between the welding material and the projections
Welding current is applied to both contact parts by pressing the contact material against each other
Welding projection welding method
The welding material is a cylindrical member, and the projection is
The step for guiding the electrode to the position near the
And a project provided on the welding material.
Section is formed in a ring shape with a notch
And one of the electrodes is guided by a step of the welding material.
The welding force and the welding current are brought into contact with the pressure receiving portion.
As added through before Symbol pressure receiving portion, the welding pressure and welding current during the welding run it is achieved by so transmitted to projection welding material from pressure receiving portion.

The object of the present invention is to provide a stepped portion for guiding an electrode to a welding material, to form a stepped shape of the welding material also serving as an electrode guide, and to make contact between the electrode and the side surface of the welding material only a stepped portion, In addition, by applying an insulating material such as paint to the side surface of the step provided in the welding material, the contact area between the electrode and the side surface of the welding material can be significantly reduced.

Furthermore, the object is a projection for positioning the welding material and the workpieces provided in the welding material, Ri by the providing a recess in the corresponding position of the workpieces
Reach is made.

[0018]

[Function] First, the upper electrode on which the welding material is attached is moved downward, and the projection formed on the welding material is pressed against the material to be welded, so that the projection and the material to be welded come into contact with each other. Then, the welding current is supplied. As a result, the contact portion generates heat due to the electric resistance of the contact portion, the projection is crushed by the pressing force, and the contact portion is melted by heating to form a nugget. At the time of forming the nugget, the required welding current is continuously supplied for a predetermined time, so that the heating and melting are sufficiently performed between the projection and the material to be welded, and the welding material and the material to be welded have sufficient welding strength. And can be welded.

During the execution of welding, the welding pressure and welding current are transmitted from the upper electrode to the projection of the welding material through the pressure receiving portion provided in the vicinity of the projection being processed into the welding material. Even if a welding current is applied only for a predetermined period of time in order to secure welding strength, the portion affected by the heat due to welding can be limited only to the vicinity of the projection, so that thermal deformation of the welding material body is reliably prevented. Therefore, it is possible to reliably prevent thermal deformation at the tip of the welding material.

Further, since the welding material is provided with a step to form a stepped shape of the welding material, the upper electrode can be guided by the step and the contact area between the upper electrode and the side surface of the welding material. Can be greatly reduced, the reactive current component of the welding current can be reduced, the surface roughness of the welding material due to sparks or the like can be largely prevented, and high-quality welding can be performed.

Furthermore, since a projection for positioning is provided, and a notch is provided in the projection provided in the welding material, positioning between the welding material and the material to be welded is easy, and a space surrounded by the projection is provided. The air that expands inside can be reliably released from this space via the cutout portion, thereby performing high-precision welding without inclining the welding material with respect to the workpiece.

[0022]

Embodiments of the projection welding method according to the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a view for explaining a projection welding method according to a first embodiment of the present invention, FIG. 2 is a view showing an example of a shape of a welding material, FIG. 3 is a view showing an example of a shape of a projection, and FIG. It is a figure showing the test result at the time of performing welding by the 1st example of the present invention. 1 and 2, 1
2 is a pressure receiving portion, 13 is a step portion, 14 is a tap,
Other reference numerals are the same as those in FIG.

In the first embodiment of the present invention, as can be seen from the side view shown in FIG. 1A and the bottom view of the welding material 1 shown in FIG. And the material 2 to be welded,
The welding is performed via a projection 11 provided on the bottom of the welding material 1 in a substantially circular ring shape. In the method according to the first embodiment of the present invention, the pressing force is applied between the welding material 1 and the workpiece 2 by the electrodes 3 and 4 provided on the upper part of the welding workpiece 1 and the lower part of the workpiece 2. In addition to this, a welding current is applied to weld the welding material 1 and the workpiece 2.

In the above description, the cylindrical welding material 1 is provided with a pressing force receiving portion 12 having a diameter larger than the diameter of the welding material 1 in the vicinity of the projection 11, that is, below the welding material 1 according to the present invention. A step portion 13 having a diameter larger than the diameter of the welding material 1 and smaller than the diameter of the pressing force receiving portion 12 is provided to the welding material 1 via a taper. An insulating material such as a paint may be applied to the side surface of the step portion 13. The upper electrode 3 has a cylindrical shape having the same inner diameter as the diameter of the step 13 of the welding material 1.

As shown in FIG. 1B, the projection 11 processed into the welding material 1 is formed in a ring shape, and is formed by providing notches at a plurality of positions of the ring. Projection 1
A conical projection 11 ′ for positioning between the workpiece 1 and the workpiece 2 is provided at the center of the projection 1. Further, a conical projection 1 of the welding material 1 of the workpiece 2
A minute depression is provided at a position corresponding to 1 ′.

When the welding material 1 configured as described above is welded to a flat plate-like workpiece 2, as shown in FIG. 1, the welding workpiece 1 is attached to the upper electrode 3 and the welding workpiece 2 is attached to the lower electrode. The projection 11 of the welding material 1 and the workpiece 2 are brought into contact with each other by moving the upper electrode 3 of the upper electrode 3 and the lower electrode 4 downward.

In this case, the inner wall of the upper electrode 3 is guided by the step 13 of the welding material 1, the tip of the upper electrode 3 is in contact with the pressing force receiving portion 12, and the welded material provided on the welding material 1 is provided. Conical projection 1 for positioning between material 2
1 ′ is fitted to the depression of the workpiece 2.

Thereafter, a required pressing force is applied between the welding material 1 and the workpiece 2 by the upper electrode 3 and the lower electrode 4, and a welding current is applied between the upper electrode 3 and the lower electrode 4 by a welding transformer (not shown). When energized, a welding current flows through the contact portions between the projections 11 and 11 ′ and the workpiece 2. As a result, Joule heat is generated in the contact portion due to the electric resistance of the contact portion, the contact portion is heated and melted, a nugget is formed in the contact portion, and the welding material 1 and the workpiece 2 are joined.

In the projection welding method according to the present invention, as shown in FIG.
It is applied from the pressure receiving portion 12 and transmitted to the projections 11 and 11 ′. Similarly, the welding current also flows from the pressure receiving portion 12, and
It will flow to 1, 11 '.

Therefore, according to the welding method according to the first embodiment of the present invention, even if a required welding current is applied for a predetermined time to obtain a sufficient welding strength, the welding is affected by heat. The parts are projected 11 and 1 of the welding material 1.
Since it can be limited only to the vicinity of 1 ′, thermal deformation of the welding material main body can be reliably prevented. As a result, thermal deformation at the tip of the welding material 1 can be reliably prevented.

Further, the first embodiment of the present invention
Since the stepped portion 13 is provided in the welding material 1 to form a stepped shape, the contact portion between the upper electrode 3 and the welding material 1 is only the side surface of the stepped portion 13 and the upper surface of the pressing force receiving portion 12. The contact area between the side surface of the upper electrode 3 and the upper electrode 3 can be greatly reduced. When the side surface of the step 13 is insulated,
The upper electrode 3 comes into electrical contact with only the pressure receiving portion. As a result, the first embodiment of the present invention can significantly reduce the reactive current component of the welding current, can significantly prevent the surface roughness of the welding material side surface due to sparks, etc. Since the welding current flowing in the contact area with the material to be welded can be made uniform,
As a result, high quality welding can be performed.

Further, the first embodiment of the present invention described above
Since a notch is provided in a part of the ring-shaped projection of the welding material, the air in the space surrounded by the inside of the ring-shaped projection and the material to be welded expands at the start of welding. Thus, it is possible to prevent the projection that is melted and to be damaged, and prevent the welding material and the material to be welded from being inclined and welded, so that higher quality welding can be performed.

FIG. 2 shows an example of the shape of the welding material applied to the welding using the ring-shaped projection according to the first embodiment of the present invention, and FIG. 3 shows an example of the shape of the projection.
This will be described below.

As shown in FIG. 3, the sectional shape of the ring-shaped projection 11 is 1.0 mm in height and 2.0 m in width.
m. Assuming that the shape of the welding material 1 has the specifications as shown in FIG.
14 × 30 = 94.2 mm. Therefore, the joint area of the projection is: ring length × width = 94.2 × 2.
0 = 188.4 mm. The material to be welded 2 is made of material SPC
C, a plate material having a plate thickness of 3.2 mm was used. As a result, the calculated tensile strength was calculated as: bonding area × tensile strength = 188.4 × 32
= 6029 kgf.

FIG. 4 shows the test results when welding is performed according to the above-described first embodiment of the present invention. As can be seen from the results of FIG. 4, sufficient welding by the method of the present invention is sufficient. The welding strength can be obtained, and the occurrence of thermal deformation of the welding material body can be surely prevented. Then, even if the tap 14 and the like as shown in FIG. 2 were processed on the main body of the welding material 1, no thermal deformation of the thread portion of the tap 14 occurred.

As described above, according to the first embodiment of the present invention, the thermal deformation of the welding material main body is not affected by the projection welding of the welding material 1 and the workpiece 2 having a long shape in the welding pressure direction. Can be reliably prevented, sufficient welding strength can be ensured, and high-quality welding can be guaranteed.

FIG. 5 is a view for explaining a welding method according to a second embodiment of the present invention. In FIG. 5, 21 is a pressing force receiving portion, 31 and 41 are ring portions, 32 and 42 are tapered portions,
Numeral 5 denotes a nugget, and other reference numerals are the same as those in FIGS. The second embodiment of the present invention is an example in which the present invention is applied to circular pipe welding.

FIG. 5A shows a second embodiment of the present invention.
5B, the upper electrode 3 is formed by a ring portion 31 and a tapered portion 32, and the lower electrode 4 is formed by a ring portion 41 and a tapered portion 42. It is configured. And the ring part 31,
Reference numerals 41 each have the same inner diameter as the outer diameter of a circular pipe to be the welding material 1 to be welded and the material to be welded 2. Also,
In the vicinity of the projections processed at the positions to be welded on the circular pipe as the welding material 1 and the workpiece 2, respectively,
Flange-shaped pressure receiving portions 12 and 21 are provided.

In the above-described second embodiment of the present invention,
When welding the tubular welding material 1 and the workpiece 2, FIG.
As shown in (b), the welding material 1 is attached to the upper electrode 3, the material to be welded 2 is attached to the lower electrode 4, and the welding material 1 is attached.
And the material to be welded 2 are brought into contact with each other.

In this case, the welding material 1 is made to penetrate the inner diameter portion of the ring portion 31 of the upper electrode 3, and the material to be welded 2 is made to penetrate the inner diameter portion of the ring portion 41 of the lower electrode 4.
4 is brought into contact with the pressure receiving portion 12 of the welding material 1 and the pressure receiving portion 21 of the material 2 to be welded, and the upper electrode 3 and the lower electrode 4 apply pressure to the welding material 1 and the material 2 to be welded. Apply pressure. Thereby, the welding pressure is applied to the pressure receiving portion 1.
2 and 21 and transmitted to the projection 11. Similarly, the welding current is also applied to these pressure receiving portions 12 and 2.
1 flows into the contact portion between the projection 11 and the workpiece 2.

By performing the welding as described above, after the welding is completed, the nugget 5 is formed as shown in FIG. 5C, and the welding can be performed with sufficient welding strength. Then, the pressure receiving parts 12, 2
By cutting 1, as shown in FIG. 5 (d), perfect circular pipe welding without thermal deformation can be performed.

FIG. 5 shows a second embodiment of the present invention.
As shown in (a), the upper electrode 3 and the lower electrode 4 have an L-shaped structure by the tapered portions 32 and 42 and the ring portions 31 and 41, and the tapered portions 32 and 42 are connected to a welding device (not shown). It can be mounted and used, and high-quality welding can be performed without causing buckling or the like even in long cylindrical welding.

According to the above-described second embodiment of the present invention,
Projection of parts affected by heat from welding 1
Since it can be limited to only the vicinity of 1, it is possible to reliably prevent thermal deformation of the welding material main body and perform high-quality welding.

[0045]

As described above, according to the present invention, in the projection welding for welding a welding material having a long shape in the welding pressure direction to the workpiece, the welding is performed at a position near the projection processed on the welding material. Since the welding material is configured by providing the pressure receiving portion and the step portion, and during welding, the welding pressing force and welding current are transmitted from the electrode to the projection of the welding material via the pressing force receiving portion, It is possible to perform the welding while reliably preventing the thermal deformation of the welding material main body and ensuring the sufficient welding strength.

Further, since the contact between the welding material and the electrode is only at the pressure receiving portion and the side surface of the step portion or only at the pressure receiving portion, the contact area between the electrode and the side surface of the welding material is reduced. It is possible to significantly reduce the size of the welding material, thereby greatly preventing the surface roughness of the side surface of the welding material due to sparks or the like, and performing high quality welding.

Further, since a projection for positioning is provided, and a notch is provided in the projection provided in the welding material, positioning between the welding material and the material to be welded is easy, and a space surrounded by the projection is provided. The air that expands inside can be reliably released from this space via the cutout portion, thereby performing high-precision welding without inclining the welding material with respect to the workpiece.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a projection welding method according to a first embodiment of the present invention.

FIG. 2 is a diagram showing an example of a shape of a welding material.

FIG. 3 is a diagram showing an example of the shape of a projection.

FIG. 4 is a diagram showing test results when welding is performed according to the first embodiment of the present invention.

FIG. 5 is a diagram illustrating a welding method according to a second embodiment of the present invention.

FIG. 6 is a diagram illustrating a projection welding method according to a conventional technique.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 welding material 2 material to be welded 3 upper electrode 4 lower electrode 5 nugget 11 projection 12, 21 pressure receiving portion 13 step portion 14 tap 31, 41 ring portion 32, 42 taper portion

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Yukio Makuta 4-6-6 Kanda Surugadai, Chiyoda-ku, Tokyo Hitachi, Ltd. (58) Field surveyed (Int. Cl. ⁶ , DB name) B23K 11/00 530 B23K 11/14 315 B23K 11/30 311

Claims (5)

(57) [Claims] 1. A welding material and a material to be welded attached to two opposing electrodes are pressed against each other by a projection provided on the welding material and a material to be welded, and a welding current is applied to a contact portion between the two. In the projection welding method, the welding material is a columnar member, and is provided with a step portion for guiding the electrode and a pressure receiving portion at a position near the projection, and is provided on the welding material.
Projection is formed into a ring with a notch
Are, one of said electrodes, projection welding, characterized in that the guided by the stepped portion of the welding material in contact with the pressure receiving portion applies a welding pressure and the welding current through said pressure receiving portion Method. 2. The projection welding method according to claim 1, wherein a side surface of the step is insulated. 3. Apart from the projections provided in the welding material, the welding material and the projection for positioning between the material to be welded is, projection welding according to claim 1 or 2, wherein the provided weld material Method. 4. A tubular welding material and a tubular workpiece to be attached to each of two opposed electrodes are pressed against each other by pressing a projection provided on the welding workpiece and the workpiece to each other. In a projection welding method in which welding is performed by applying a welding current to a contact portion, the welding material is provided with a pressure receiving portion at a position near the projection, and the projection is pressed against the workpiece. A pressure receiving portion is provided in a vicinity position, and the two electrodes are provided with a ring portion for holding a circular pipe of a welding material and a material to be welded. A projection welding method, wherein a pressing force and a welding current are applied through the pressing force receiving portion. 5. The projection welding method according to claim 4 , wherein the pressure receiving portions provided on the welding material and the material to be welded are cut and removed after welding is completed.