JPH0334220A - Processing method for rivet type contact - Google Patents

Abstract

PURPOSE:To prevent the cracking of a head part by preliminarily molding a wire cut contact material nearly into the finish form of a rivet type. CONSTITUTION:For example, a wire cut contact material 1 having an outer diameter of 1.45mm and a height of 2.4mm formed of 11.7% of sintered Ag-SnO2 is preliminarily molded into a nearly finished rivet type contact 3'(5mm leg diameter and 1.3mm height) provided with a head part 2' (1.85mm head diameter and 0.58mm head thickness) having a protruding part 2a (0.9mm outer diameter and 0.03mm height) on the head part center, and then finished into a rivet type contact 5 having a disk head part 4 (2mm head diameter and 0.5mm head part thickness) by a certain plastic deforming amount. Hence, the occurrence of cracking in the thin head part can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for manufacturing rivet-type contacts to be attached to electrical contacts used in switches, relays, breakers, etc.

(Prior Art) Conventionally, in order to process a rivet-type contact, wire-cut contact material l shown in FIG. It was then molded into a rivet-type contact 5 having a disk-shaped head 4 as shown in FIG. 2C.

(Problem to be Solved by the Invention) By the way, in the above-described processing method for a rivet type contact, since the amount of deformation from the preformed head 2 to the final formed head 84 is large, it is mechanically fragile and has a narrow processing limit width. In the case of the contact material 1 made of sintered material, when it is preformed, cracks occur around the finished, disc-shaped head 4 due to work hardening and internal stress that occur on the tapered peripheral surface of the head 2. Something happened. In addition, the contact material 1 made of a sintered material with a narrow processing limit width has an area increase rate of approximately 50%, but even if it is less than 50%, cracks will occur more frequently as the contact head thickness becomes thinner. .

Therefore, the cracking limit is determined by the relationship between the area increase rate and the upsetting ratio.

However, the current trend is for switches and relays to become thinner, and contacts are also becoming thinner.

Therefore, the present invention aims to provide a method for processing a rivet type contact with a low upsetting ratio and without causing cracks in the thin head, even when making a rivet type contact using a contact material made of sintered material. It is something.

(Means for Solving the Problems) In order to solve the above problems, the method of processing a rivet-type contact of the present invention involves preforming a wire-cut contact material into a shape close to the finished shape of the rivet type, and then It is characterized by finishing molding into a rivet shape with a slight amount of plastic deformation.

(Function) As described above, in the method of processing a rivet-type contact of the present invention, the wire-cut contact material is preformed into a shape close to the finished shape of the rivet-type, but since the wire-cut contact material is in a fully annealed state. , hard to crack in preforming. Further, even if work hardening occurs in the outer shoulder portion during preforming and internal stress accumulates, cracks will not occur because only a small amount of plastic deformation is required in the final forming.

(Example) An example of the method of processing a rivet-type contact of the present invention will be described with reference to the drawings.As shown in Fig. 1a, the outer diameter is 1.45 mm,
A wire-cut contact material 1 made of sintered Ag-3n○, 11.7%, with a height of 2.4 mm is used, as shown in Figure 1, with a head diameter of 1.85111 m and a head thickness of 0.58111 [+1
The outer diameter is 0.0 mm at the center of the upper surface of the head. hm, a head 2' having a convex portion 2a with a height of 0.03 mm, and a leg diameter of 1.5 mon.
, leg height L, preformed into a rivet type contact 3' with a finish close to 3 mm, and then a slight amount of plastic deformation to form Fig. 1C.
A rivet-type contact 5 having a disk-shaped head 4 with a head diameter of 2 mm and a head thickness of 0.5 mm was finished molded as shown in FIG.

On the other hand, to explain a conventional example using a diagram, as shown in Fig. 2a, a sintered Ag-3 with an outer diameter of 1.45 mm and a height of 2.4 mm is used.
A wire-cut contact material l made of 11.7% NO□ was cut into a lump-like head with a head bulge diameter of 1.6 mm, an upper surface of @ part 1.1 mm, and a height of 0.78 mm, as shown in Fig. 2. 2, and is preformed into a rivet type contact 3 with a leg diameter of 1.5 mm and a leg height of 1.3 mm, and then, as shown in FIG. 2C, a head diameter of 2 and a head thickness of 0. A rivet type contact 5 having a disk-shaped head 4 of 5+nn+ was finished molded.

Rivet type contacts 650 of the thus obtained embodiment and conventional example
After quality inspection of 00 pieces, 526 conventional rivet type contacts had cracks around the head 4.
In contrast, none of the rivet-type contacts of the Examples had cracks around the head 4.

Preforming in the method of processing a rivet-type contact of the present invention is preferably carried out within a range of 85 to 98% of the head diameter at the time of final forming. This is because during final forming, processing with a small amount of plastic deformation of 2 to 15% is sufficient, so no cracks occur.

(Effects of the Invention) As can be seen from the above explanation, according to the method for processing a rivet-type contact of the present invention, cracks occur in the thin head even when a rivet-type contact is made from a contact material made of sintered material. This has the effect of making it possible to create rivet-type contacts without causing any damage.

[Brief explanation of drawings]

FIGS. 1A to 1C are diagrams showing the steps of the method for manufacturing a rivet type contact according to the present invention, and FIGS. 2A to C are diagrams showing the steps of the conventional method for manufacturing a rivet type contact.

Claims (1)

[Claims] 1. A method for processing a rivet-type contact, which is characterized by preforming a wire-cut contact material into a shape close to the finished shape of a rivet type, and then final forming it into a rivet type with a slight amount of plastic deformation.