JPS60143218A - Clamping tool for welding - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention is utilized in the technical field of welding fasteners used by being welded to objects, and includes a welding fastener having a triangular cross section on the weld joint surface side. The present invention relates to a welding fastener having a ring-shaped protrusion, which has been improved to improve welding results.

(Prior Art) Fasteners that are used by pressing the fastener against an object and welding the two are well known.

On the other hand, so-called projection welding is also well known, in which a projection is provided on a part of the joining surfaces to be welded, the welding surfaces are pressed against each other, and a potential difference is applied therebetween to weld at the projection.

Therefore, the inventor came up with the idea of providing a ring-shaped protrusion on the contact surface of the fastener and performing welding at this part.
It is known from the '58 publication. However, the fastener disclosed in Japanese Utility Model Publication No. 49-49358 is not intended for welding, but for preventing loosening of the fastener. However, by simply providing such a ring-shaped protrusion, it is not possible to obtain a fully satisfactory welding result.

That is, in a bolt a as a fastener as shown in FIG.
When a ring-shaped protrusion e with a triangular cross section is provided, projection welding is performed by applying a potential difference between the plate f and the pole 8a while pressing the plate f, which is the object to be welded, against the joint surface d. Then, the link-like protrusion e melts, and then the entire surface of the joint surface d contacts the surface of the plate f, and the welding current is dispersed at this contact surface, resulting in insufficient welding. Furthermore, since the outer edge of the head plate cannot be fully welded,
There is also the problem that it leads to the formation of associations and causes defects when the outside is electrodeposited or painted.

(Object of the Invention) An object of the present invention is to provide an improved welding fastener that can solve the above-mentioned problems.

(Structure of the Invention) The structure of the present invention is that a protrusion having a substantially triangular cross section is provided in a ring shape on the welded joint surface, and the step between the tip of the ring-shaped protrusion and the outer flange surface is the protrusion. The height difference between the tip of the flange and the inner flange surface is set to be small.
The welding fastener is characterized in that the cross-sectional shape of the ring-shaped protrusion is such that the angle of inclination of the outer surface thereof is smaller than the angle of inclination of the inner surface with respect to a line parallel to the axis passing through the tip of the protrusion. It is something.

(Embodiment) Next, an embodiment of the present invention will be described in detail with reference to FIGS. 1 to 4. \ 1 is a steel bolt as a welding fastener according to an embodiment of the present invention. The bolt 1 consists of a head 2 and a threaded portion 3.

The threaded portion 3 side of the head 2 is configured as a welding joint surface 4, and a projection 5 having a triangular cross section is provided on this welding joint surface 4 so as to integrally go around in a ring shape.

The outer flange surface 4a of the projection 5 on the welding joint surface 4 is set higher than the inner flange surface 4b by an amount H as shown in the figure. That is, the level difference between the tip of the protrusion 5 and the outer flange surface 4a is the same as that between the tip of the protrusion 5 and the inner flange surface 4a.
It is set smaller than the difference in height from b. In addition, in the cross-sectional shape of the protrusion 5, the inclination angle Oa of the outer surface 5a with respect to a line parallel to the center line Lc passing through the tip of the protrusion 5 is larger than the same inclination angle θb of the inner surface 5b. In this embodiment, the inclination angles are θa of 40 degrees and Ob of 30 degrees.

A mounting hole 6a drilled in an object to be welded to the bolt 1 constructed in this manner, for example, a steel plate 6 of a frame.
Then, the threaded portion 3 is inserted, and the ring-shaped protrusion 5 is brought into contact with the steel plate 6. Then, electrodes (not shown) of a welding power source (not shown) are connected to the poles 1 to 1 and the steel plate 6, and then these are pressed together.

Then, the contact area between the ring-shaped protrusion 5 and the steel plate 6 is heated by Joule heat due to the contact resistance at the contact area 1+.
The ring-shaped protrusion 5 is melted. At this time, the ring-shaped protrusion 5
The inclination angle θa of the outer surface 5a is larger than the inclination angle O of the inner surface 5b.
b, the outer surface 5a has a larger amount of penetration than the inner surface 5b, and therefore most of the molten metal M of the ring-shaped protrusion 5 flows toward the outer surface 5a (Fig. 3). (Illustrated)
. As the welding progresses further, the steel plate 6 and the outer flange surface 4a come into contact and this portion is slightly melted and welded, completing the projection welding.

In addition to the embodiments described above, this invention can also be modified as described below.

(a) In addition to bolts, the fasteners may be of other known constructions such as the nuts 1 to 1.

(b) The cross-sectional shape of the ring-shaped protrusion may be triangular or other shapes such as a substantially triangular shape, and the inclination of the inner and outer sides of this cross-sectional shape is determined by the angle of inclination of the outer surface and the angle of inclination of the inner surface. It may be set to an appropriate value within a larger range.

The experimental results of the embodiment shown in FIG. 1 and the comparative example shown in FIG. 1 are shown in FIG. 6 and subsequent figures. That is, for the purpose of this invention, which is to obtain a small amount of weld penetration over the entire outer periphery in order to prevent the occurrence of knots, setting the angle of the protrusion is important.

That is, as in the comparative examples shown in FIGS. 6 and 7, the molten metal M flows into the side where the protrusion inclination angle Oa is larger, and from the perspective of the intention of the present invention, the molten metal M flows into the protrusion as shown in FIG. The outer surface inclination angle Oa needs to be larger than the inner surface inclination angle Ob.

(Effects of the Invention) The effects of the invention described above are listed below.

(1) A ring-shaped protrusion with a triangular cross section is provided on the weld joint surface, and the inclination angle of the outer surface is larger than the inclination angle of the inner surface, so that the penetration during projection welding is
The inner side of the ring-shaped protrusion is suppressed and the outer side is increased, and the outer periphery of the ring-shaped protrusion is mainly melted, so that the effect of preventing rust on the outer surface is improved.

(2) Furthermore, since the outer flange surface of the ring-shaped protrusion is set higher than the inner flange surface, after the ring-shaped protrusion is melted, the outer flange surface comes into contact with the object to be welded, and further melting takes place, Deep grooves are not formed on the outer periphery of the welded area, and the electrodeposition during electroplating is sufficient to prevent formation of bonds. You can also expect reliable airtightness in areas that require airtightness.

(3) Since the flange surface is provided with a ring-shaped protrusion on the outside of the welding joint surface, the welding current is concentrated on this protrusion.
Eliminating reactive current not only saves energy, but also extends the life of the welding tool. Further, since the protrusion has a flange surface on the outside thereof, when the protrusion is completely melted, the melting of the side surface 2a does not occur.

[Brief explanation of the drawing]

Figures 1 to 4 show one embodiment of the present invention.
The figure is a partial vertical sectional view, Figure 2 is a view taken in the direction of arrow II in Figure 1, and Figure 3 is a partial longitudinal sectional view.
This figure and FIG. 4 are partial longitudinal cross-sectional views for explaining the operation. FIG. 5 is a partially longitudinal side view for comparison with the present invention, FIGS. 6 and 7 are cross-sectional views of an experimental example for comparison with the embodiment of the present invention, and FIG. 8 is an embodiment of the present invention. FIG. 1... Bolt (welding fastener), 4... Welding joint surface, 4a... Outer flange surface, 4b...
...Inner flange surface, 5...Protrusion, 6.
Steel plate (object) Oa... Outer surface inclination angle, Ob...
...Inner surface inclination angle Fig. 3 Fig. 4

Claims (1)

[Claims] (1) In a welding fastener that is used by being welded to an object, a protrusion with a roughly triangular cross section is provided in a ring shape on the welding joint surface, and the tip of the ring-shaped protrusion and the outer The level difference between the flange surface and the inner flange surface is set smaller than the level difference between the tip of the protrusion and the inner flange surface, and the cross-sectional shape of the ring-shaped protrusion has an inclination of the outer surface with respect to a line parallel to the axis passing through the tip of the protrusion. A welding fastener characterized in that a corner is larger than an inclination angle of an inner surface.