JPS6359488B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method of manufacturing an electrical contact. To make a single-headed electrical contact, the contact material is brazed or welded to the base material, or the contact mounting hole is drilled in the base material and the contact material is inserted into the hole and swaged. . However, each of these methods has its advantages and disadvantages, and the reality is that it is not possible to obtain sufficiently satisfactory bonding strength and twisting strength of the contact point. However, recently there has been a demand for high reliability of electrical contacts, and especially for electrical contacts used in the safety systems of various electrical devices that affect life and death, the bonding strength and twisting strength of the contacts have become important. It must not be weak and cause the contacts to rattle, peel, or fall off. The present invention was made in view of this point, and it is an object of the present invention to create an electric contact that has strong contact bonding strength and torsion strength, and that does not cause the contact to rattle, peel off, or fall off. We aim to provide a method that can be used. As shown in FIG. 1a, the method for manufacturing an electric contact of the present invention involves drilling a contact mounting hole 2 at a predetermined position in a base material 1, and attaching a taper 2a to the lower opening edge of the contact mounting hole 2. Then, the contact material 3 is inserted into the contact mounting hole 2 and caulked to form the head of the contact 4 on the upper side of the contact mounting hole 2 as shown in Fig. 1b. A caulking part 5 is formed in the expanded lower end opening of 2, and the back surface of the contact 4 is attached to the base material 1.
Then, as shown in FIG.
The electrical contact 12 is made by applying current to the contact 4 and the base material 1 through an upper electrode 11 provided at the center of the contact 4 and performing resistance welding. In the method for manufacturing an electrical contact of the present invention, the reason why the caulking portion 5 is insulated and the contact portion between the contact 4 and the base material 1 is resistance welded after caulking the contact material 3 is as follows. During caulking, the upper opening edge of the contact mounting hole 2 of the base material 1 is crushed and deformed, and the lower surface of the outer peripheral side of the contact 4 rises above the upper surface of the base material 1, creating a gap, which reduces the bonding strength and twisting of the contact 4. Since the rotational strength is weak, the contact 4 and the base material 1 are pressure welded at the upper opening edge of the contact mounting hole 2, and the joint strength and twisting strength of the contact 4 are improved by the synergistic effect of caulking and welding. It is for this purpose. In addition, in the method for manufacturing an electric contact of the present invention,
The contact material 3 to be inserted into the contact mounting hole 2 of the base material 1 is made by cutting a contact wire material in advance to a predetermined size as shown in the figure, but is not limited to this. Alternatively, the contact material formed into a rivet mold may be cut into the contact mounting hole 2 using a parts feeder.
It is also possible to insert it into the holder. Further, in the method for manufacturing an electric contact of the present invention,
After the contact material 3 is caulked into the contact mounting hole 2 of the base material 1, the depth of the recess 9 of the upper electrode 11 used for welding the contact 4 and the base material 1 is made smaller than the height of the contact 4. The lower surface 10 of the upper electrode 11 never comes into contact with the upper surface of the base material 1 during welding. The shape of the recess 9 is not limited to the one shown in the drawings, and there are various shapes corresponding to the shape of the head of the contact 4 to be caulked. Also, the lower electrode 8
The insulating material 6 buried in the center of the upper surface 7 has a size larger than the diameter of the caulking part 5 of the contact 4.
The caulked portion 5 is never brought into direct contact with the lower electrode 8 during welding. Next, in order to clarify the effects of the method of manufacturing an electric contact of the present invention, specific examples and conventional examples thereof will be described. [Example] BSR with a width of 5 mm and a thickness of 0.6 mm as shown in Figure 1a.
(brass strip) at the required position on the base material 1 made of
A contact mounting hole 2 of mm is drilled, a 45 degree taper 2a is attached to the lower opening edge of the contact mounting hole 2, and the contact mounting hole 2 is widened to a depth of 0.2 mm and a width of 0.2 mm. Ag-10w/oCu with diameter 1.2mm and height 3.46mm
A contact material 3 consisting of the above is inserted and caulked to form a contact material 3 having a lower end outer diameter of 2.5 mm, a contact surface diameter of 2 mm, and a height of 0.8 mm on the upper side of the contact mounting hole 2 as shown in Fig. 1b.
At the same time, a caulking part 5 with a diameter of 1.85 mm is formed in the enlarged lower end opening of the contact mounting hole 2 so that the back surface of the contact 4 is flush with the back surface of the base material 1, and then the first As shown in Figure c, an insulating material 6 with a diameter of 2 mm and a thickness of 0.3 mm is buried in the center of the upper surface 7. A contact is formed by a lower electrode 8 of 6 mm and an upper electrode 11 of 4 mm in diameter, which has an opening diameter of 2.3 mm corresponding to the shape of the head of the contact 4, a bottom diameter of 2 mm, and a recess 9 of 0.3 mm in depth in the center of the lower surface 10. 4 and the base material 1 were energized and resistance welded to make an electric contact 12. [Conventional example 1] As shown in Fig. 2, a trapezoidal cross-section of Ag with a contact surface diameter of 2 mm and a bottom diameter of 2.5 mm is placed at the required position on the upper surface of the base material 1 made of BSR (brass strip) with a width of 5 mm and a thickness of 0.6 mm. −
Electric contact 12' was made by welding contact 4 made of 10w/oCu. [Conventional example 2] BSR with a width of 5 mm and a thickness of 0.6 mm as shown in Figure 3a.
(brass strip) at the required position on the base material 1 made of
A contact mounting hole 2 of mm is drilled, a 45 degree taper 2a is attached to the lower opening edge of the contact mounting hole 2, and the contact mounting hole 2 is widened to a depth of 0.2 mm and a width of 0.2 mm. Ag-10w/oCu with diameter 1.2mm and height 3.46mm
The head of the contact 4 with a lower end outer diameter of 2.5 mm, a contact surface diameter of 2 mm, and a height of 0.8 mm is attached to the upper side of the contact mounting hole 2 by crimping and forming the contact material 3, as shown in Fig. 3b. The electric contact 12'' is formed with a caulking part 5 of 1.85 mm in diameter at the enlarged lower end opening of the contact mounting hole 2 so that the back surface of the contact 4 is flush with the back surface of the base material 1. The bonding strength and torsion strength of the contact 4 to the base material 1 were measured for each of 100 electrical contacts 12' and 12'' of the electrical contact 12 of the above embodiment and conventional examples 1 and 2. , as shown in the table below. Here, the bonding strength was measured using a tensile tester by pressing the contact head parallel to the top surface of the base material, and the twisting test was measured using a torque driver with slotted grooves provided on the contact head.

[Table] As is clear from the table above, the electrical contact of the example has much stronger bonding strength and torsion strength than the electrical contacts of conventional examples 1 and 2, and is stable with less variation. . The electrical contact 12 manufactured by the manufacturing method of the present invention is then subjected to finishing molding as required. As described above in detail, the method for manufacturing an electrical contact of the present invention has the excellent effect of easily producing an electrical contact with strong bonding strength and twisting strength.

[Brief explanation of the drawing]

FIGS. 1a, b, and c are cross-sectional views showing the steps of the method for manufacturing an electric contact according to the present invention; FIG. 2 is a cross-sectional view showing an example of the conventional method for manufacturing an electric contact; FIGS.
b is a sectional view showing another example of the conventional method of manufacturing an electric contact; DESCRIPTION OF SYMBOLS 1... Base material, 2... Contact mounting hole, 3... Contact material, 4... Contact, 5... Caulking part, 6... Insulating material, 7... Upper surface of lower electrode, 8... Lower electrode, 9
... recess, 10 ... lower surface of upper electrode, 11 ... upper electrode, 12 ... electric contact.

Claims (1)

[Claims] 1. Drill a contact mounting hole at the required position on the base material, taper the lower opening edge of the contact mounting hole to widen it, then fit the contact material into the contact mounting hole and caulk it. to form the head of the contact on the upper side of the contact mounting hole, and also form a caulking part in the enlarged lower end opening of the contact installation hole so that the back surface of the contact is flush with the back surface of the base material, and then the caulking part is formed. The lower electrode has an insulating material embedded in the upper center surface so that no current is applied to the contacts, and the upper electrode has a recess in the lower center surface that corresponds to the shape of the head of the contact, and the contact and base material are energized for resistance welding. A method for manufacturing an electric contact.