JPS61169180A - Spot welding device - Google Patents

Abstract

PURPOSE:To avoid a nut removal and to prevent a magnet wear by coating the component attraction side of a magnet with the protecting plate made of non magnetic body and by surrounding the other parts with the member of ferromagnetic body. CONSTITUTION:The tip of a component feeding pipe 8 is fixed to the end face 10 of a guide pipe 7 and a tack welded chamber 11 is formed on one part thereof. A magnet 9 is composed by fitting a magnet piece 20 into the hole 19 of the center of the thick plate 18 of ferromagnetic body. The component attraction side of the magnet 9 is coated by the protecting plate 21 of non- magnetic body and the opposite side is coated by the shielding plate 22 of magnetic body. A welding is performed by reaching a nut 5 on a plating component with pushing down it by a pushing out face 26 when a feeding rod 6 is advanced. In this case the nut removal can be avoided because of the attraction force of the magnet 9 being gradually lowered with the pushing down of the nut 5. The wear of the magnet 9 can be prevented as well due to the protection plate 21 covering the magnet 9.

Description

Detailed Description of the Invention (a) Industrial Application Field The present invention is a spot welding device including a component supply device, which temporarily retains components in a temporary fixing chamber with a magnet. It is used in the field of electrical resistance welding of 7" logic nuts to sheet metal parts such as automobiles and home appliances. More specifically, it is used to weld sheet metal parts mounted on fixed electrodes. After a projection nut is supplied from a component supply device, a movable electrode advances to spot weld the nut to a sheet metal component.

BACKGROUND OF THE INVENTION Conventionally, a component supply device forming a part of a spot welding device as described above has a temporary retaining magnet that directly attracts and holds components in a single state.

e→Problem to be Solved by the Invention According to the above-mentioned prior art, since the magnet is arranged as a single unit, when a component that has been sliding on the magnet surface separates from the magnet, the sliding resistance increases. Because of this instantaneous disappearance, a supply rod for extruding parts operated by an air cylinder is rapidly accelerated, which causes a problem in that the parts held by the supply rod come off from the rod. Also,
Since the component is directly attracted to the magnet and the component slides as described above, abnormal wear occurs on the magnet surface, and in extreme cases, the holding posture of the component may become distorted.

2) Means to solve all the problems and their effects The main point of the solution is to cover the component attracting side of the magnet with a non-magnetic protective plate, and surround the other parts with magnetic members. By such means, the above-mentioned sliding resistance is gradually weakened and wear is also prevented.

(g) Example The overall structure of the spot welding device according to the present invention is such that a fixed electrode 1 and a movable electrode 2 are arranged substantially coaxially, a sheet metal part 6 is placed on the fixed electrode 1, and a sheet metal part 6 is placed on the fixed electrode 1. The movable electrode 2 is brought into close contact with the projection nut 5 supplied from the component supply device 4 to perform electric resistance welding.

The parts supply device 4 mainly consists of a supply rod 6, a guide pipe 7 that guides it, a parts supply pipe 8 connected to a parts feeder (not shown), and a magnet 9. Referring to FIG. 2 and subsequent figures, the tip of the component supply tube 8 is brought into close contact with the end surface 1o of the guide tube 7, and both are fixed by any suitable method, such as welding.

The parts supply pipe 8 is connected to the front and back of the nut 5 and the direction f iE L
It has a rectangular cross section in order to maintain the shape, and is provided with a notch 12 that forms a temporary fixing chamber 11.

A flat surface 14 is formed by the cutout 15 at the lower part of the guide tube 70, and the flat surface 14 is completely flush with the end surface 15 of the component supply w8. The magnet 9, which has a slightly flattened rectangular parallelepiped shape, is a permanent magnet, and is fixed in a pressed state against the flat surface 14 and the end surface 15, as is clear from FIGS. 2 and 6. For this purpose, the entire support fitting 16 is firmly welded to the outer peripheral surface of the guide tube 7, and the aforementioned pressing force is obtained by the bolt 17 screwed into this.

For the magnet 9, a hole 19 is completely drilled in the center of a thick plate 18 made of a magnetic material, and a magnet piece 20 is fitted therein.The part attracting side is covered with a protective plate 21 made of a non-magnetic material, and the opposite side is covered with a protective plate 21 made of a magnetic material. Shielding plate 2
Covered with 2. Suitable non-magnetic materials include, for example, stainless steel, specifically chromium-nitrous stainless steel with an austenitic structure, and suitable ferromagnetic materials include iron and nickel, for example.

By selecting the materials as described above, sudden changes in sliding resistance and magnet wear can be prevented by the effects described below.

The supply rod 6 inserted into the guide hole 23 in the guide tube 7 has a large-diameter rod portion 24 and a small-diameter rod portion 24 that enters the threaded hole of the nut 5, but is composed of an id portion 25 and is pushed out to the boundary between the two. Surface 26 is provided. However, Fig. 7 shows another magnet type in which the bottomed hole '19 is completely opened in the day plate 18, a magnet piece 20 is fitted therein, and a protection plate 21 is attached. R is required. Further, 27 in the diagram VJ1 is an air cylinder by which the supply rod is moved forward and backward.

FIG. 2 shows a state in which the nut 5 is attracted by the magnet 9 and is temporarily locked in the temporary locking chamber 11, and the supply rod 6 is now
When the nut 5 advances, the guide portion 25 enters the screw hole of the nut 5, pushes the nut 5 down with the extrusion surface 26, and reaches the sheet metal part 3 as it is. Thereafter, the movable electrode 2 is operated to complete welding of the nut.

(f) Effect: In the temporarily fixed state shown in Fig. 2, the nut 5 is completely opposed to the magnet piece 20, so the attraction force of the magnet piece acts the strongest, and therefore the sliding resistance in this area is the greatest. be. Since the protective plate 21 is made of a non-magnetic material, the magnetic force is faithfully transmitted to the nut. When the nut 5 is pushed down and comes to a position slightly below the position of the magnet piece in Figure 2, the attraction force decreases slightly.
Furthermore, the suction force decreases in proportion to the pushing distance n, and the sliding resistance gradually decreases.

Therefore? I! This eliminates sudden changes in dynamic resistance, and avoids the aforementioned nut four-fold problem. Furthermore, since the magnet surface is covered with the protective plate, there is no problem of magnet wear, and it is also possible to use a synthetic resin plate with excellent wear resistance as the protective plate.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, in which FIG. 1 is a simplified side view showing the entire device, FIG. 2 is a longitudinal side view showing the main parts of the parts supply device, and FIG. Fig. 42 is a view from arrow (5), Fig. 4 is a three-dimensional view of the end of the guide tube, Fig. 5 is a three-dimensional view of the end of the component supply pipe, Fig. 6 is a three-dimensional view of the magnet, and Fig. 7 is a three-dimensional view of the end of the guide tube. It is a sectional view showing the entire magnet structure.

Claims (1)

[Claims] In a spot welding device that supplies a projection nut from a component supply device onto a sheet metal component placed on a fixed electrode, and then welds the nut to the sheet metal component by advancing a movable electrode, one of the component supply devices is on a component delivery side. This type has a temporary locking chamber that is opened to the outside and into which a component supply rod enters from the other side, and is equipped with a magnet that forms the inner wall of the temporary locking chamber and that attracts and temporarily locks the components. A spot welding device characterized in that the component attracting side of the magnet is covered with a protective plate made of a non-magnetic material, and the other parts are surrounded by a member made of a magnetic material.