JP3058235B2 - Method of manufacturing rivet type electrical contact - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a rivet type electric contact, and more particularly to a method of manufacturing a rivet type electric contact suitable for automatically caulking a spring material into a contact mounting hole.

[0002]

2. Description of the Related Art Conventionally, a method of manufacturing a rivet-type electrical contact has been generally carried out by using a die 1 as shown in FIG.
Then, as shown in FIG. 3b, a head 5 having a frustoconical shape is preformed by a first punch 4 as shown in FIG. As shown in (c), the frustum-shaped head 7a is finish-formed with the second punch 6 to form the rivet-type electric contact 8.

In recent years, as shown in FIG.
A large-diameter concave portion 9 is provided in the periphery of the opening of the contact material insertion hole 2 and the cylindrical contact material 3 inserted into the contact material insertion hole 2 is inserted into the upper mold 10 in the concave portion 9 as shown in FIG. A rivet-type electrical contact 12 is formed by shaping a disk-shaped head 11. (Prior art 4-7
No. 5109).

In the former method of manufacturing a rivet-type electrical contact, which is generally performed, as shown in FIG.
Due to the center misalignment between the punch 6 and the die 1, a center misalignment between the head 7a and the leg 7b of the rivet type electrical contact 8 of 0.03 to 0.15 mm occurs as shown in FIG. 7 is tapered to prevent product adhesion, when the material volume is small, the periphery of the lower end of the head becomes round as shown in FIG. 7 and the head diameter becomes small, and when the material volume is large, FIG. As shown in the figure, burrs 13 are formed on the lower edge of the head.

In the latter method of manufacturing a rivet-type electric contact, the upper die 10 is inserted into the large-diameter concave portion 9 provided on the peripheral edge of the opening of the contact material insertion hole 2 of the die 1.
The inner peripheral surface of the upper mold 10 and the outer peripheral surface of the tip end of the upper mold 10 are rubbed and worn, and burrs 14 are formed on the periphery of the upper surface of the head of the obtained rivet-type electrical contact 12 as shown in FIG. This leaves a foil-like flutter 15 as shown in FIG.

On the other hand, as shown in FIG. 11, a rivet-type electric contact is aligned and supplied by a parts feeder 16, and the rivet-type electric contact is intermittently supplied onto a receiving mold 17 as shown in FIG. Is sent to the contact mounting hole 19 of the hoop-shaped spring material 18 and swaged with the swaging mold 20, but the head diameter fluctuates as described above, or the head and legs are misaligned In this case, the feed amount of the rivet-type electrical contact as viewed from the foot portion changes each time, the leg portion does not enter the contact mounting hole 19 of the spring material 18, the hook is caught, and the automatic swaging is interrupted.

[0007]

SUMMARY OF THE INVENTION Therefore, the present invention can greatly reduce the variation of the head diameter, and can greatly suppress the center displacement between the head and the leg, so that the spring material can be inserted into the contact mounting hole. It is an object of the present invention to provide a method for producing a rivet-type electrical contact that can be performed smoothly without interrupting automatic caulking.

[0008]

According to the present invention, there is provided a method for manufacturing a rivet-type electrical contact, comprising the steps of: providing a large-diameter hole having a depth of 0.2 to 0.6 mm around an insertion hole of a cylindrical contact material; A cylindrical contact material is inserted into the insertion hole of the die having a concentric concave portion, and a frustum-shaped conical head is preformed by a first punch. A second punch having a truncated-cone-shaped concave portion on the tip end surface is formed into a disk-shaped or thin-shaped head by finish molding.

[0009]

As described above, in the method for manufacturing a rivet-type electric contact of the present invention, the head of the rivet-type electric contact is placed in a recess having a depth of 0.2 to 0.6 mm and provided concentrically around the opening of the die insertion hole. The second punch having a flat tip surface or the second punch having a truncated conical recess formed on the tip surface is formed into a disc or thin shape. Since a vertical straight portion is always formed on the outer peripheral surface of the head of the rivet-type electric contact, the variation of the head diameter is greatly reduced. In addition, the die is made of carbide, and the center hole is suppressed to 0.01 mm or less because the insertion hole of the cylindrical contact material and the recess at the periphery of the opening are made by electric discharge machining. The center displacement between the head and the leg of the electrical contact is greatly reduced.

The reason why the depth of the concave portion of the die is set to 0.2 to 0.6 mm is that when the depth is less than 0.2 mm, the variation in the volume of the cylindrical contact material cannot be absorbed, and when the depth exceeds 0.6 mm, the finish molding is performed. This is because a vertical straight portion is not formed on the outer peripheral surface of the rivet head, and the variation in the head diameter cannot be reduced.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the method for manufacturing a rivet type electric contact according to the present invention will be described with reference to the drawings. As shown in FIG. 1A, the periphery of an opening of a contact insertion hole 2 having a diameter of 1.45 mm of a die 1 made of carbide. A concavity 21 having a depth of 0.4 mm and a diameter of 3.0 mm is formed concentrically by electric discharge machining in the portion, and the contact insertion hole 2 of the die 1 is
A 0.6 mm long cylindrical contact material 3 made of AgcdO 12 wt% having a diameter of 1.4 mm and a length of 2.48 mm is inserted. Then, as shown in FIG. A preform is formed on a frusto-conical head 5 'having a height of 2.37 mm and a height of 1.06 mm. Thereafter, as shown in FIG. 1C, the second punch 22 having a flat tip surface has a diameter of 3.0 mm and a thickness of 0.4. The rivet-type electric contact 24 was obtained by finish-molding the disk-shaped head 23 of mm.

Next, another embodiment will be described with reference to the drawings.
As shown in FIG. 2a, the diameter of the die 1 made of carbide is 1.45.
0.4 mm depth, 3.0 mm diameter at the periphery of the opening of the contact insertion hole 2 mm
A concavity 21 having a diameter of 1.4 mm and a length of 2.41 mm is formed in the contact insertion hole 2 of the die 1.
A cylindrical contact material 3 of 12 wt% is inserted in a length of 0.6 mm, and then, as shown in FIG.
A frustum-shaped conical head 5 ″ having a diameter of 1.3 mm, an outer diameter of 2.16 mm and a height of 1.76 mm was preformed, and then a frusto-conical recess 25 was provided on the tip surface as shown in FIG. 2 Punch 26, top diameter 2.
A rivet-type electric contact 28 was obtained by finishing a thin head 27 having a tapered outer peripheral surface at a site of 89 mm, an outer diameter of 3.0 mm, a height of 0.6 mm, and a height of the upper half of 0.3 mm.

With respect to the rivet-type electrical contacts 24 and 28 of each embodiment obtained in this manner, the center deviation of the head and the leg was examined by 30 pieces each. The center deviation between the head and the leg in the case of the obtained rivet type electric contact was remarkably less than the range of 0.03 to 0.05 mm. Further, the rivet type electric contact 24 of each of the above embodiments,
The variation of the head diameter (3.0 mm diameter) was examined for 30 pieces of each 28, and the variation in the head diameter (3.0 mm diameter) of the rivet-type electrical contact obtained by the conventional method in the range of 3.01 to 3.02 mm diameter was examined. Significantly less than the range of 3.01 to 3.08 mm.

[0014]

As described above, according to the method for manufacturing a rivet-type electric contact of the present invention, in manufacturing the rivet-type electric contact, the variation in the diameter of the head can be greatly reduced, and the head and the leg can be formed. Center deviation can be greatly reduced. Therefore, the rivet type electrical contact thus manufactured is fed by the parts feeder, and the leg can be correctly inserted into the contact mounting hole of the spring material, without interrupting the automatic caulking.
It can be done smoothly.

[Brief description of the drawings]

FIGS. 1a, 1b and 1c are views showing steps of an embodiment of a method for manufacturing a rivet type electric contact of the present invention.

2 (a), 2 (b) and 2 (c) are views showing steps of another embodiment of the method for producing a rivet type electric contact of the present invention.

FIGS. 3A, 3B and 3C are diagrams showing steps of a conventional method for manufacturing a rivet-type electric contact.

FIGS. 4A and 4B are diagrams showing steps of another example of a method for manufacturing a conventional rivet-type electrical contact.

FIG. 5 is a view showing a center shift between a second punch and a die in FIG. 3c.

FIG. 6 is a view showing the center displacement of the head and the leg of the rivet type electric contact formed by the second punch and the die of FIG. 5;

FIG. 7 is a view showing a case where the material volume when the head is formed by the second punch in FIG. 3C is small.

8 is a diagram showing a case where the material volume is large when the head is formed by the second punch in FIG. 3c.

FIG. 9 is a view showing a state in which burrs are formed on the periphery of the upper surface of the head of the rivet-type electrical contact obtained by the manufacturing method shown in FIGS.

FIG. 10 is a view showing a state in which a foil-like fluttering remains even when the head of the rivet-type electric contact of FIG. 9 is polished.

FIG. 11 is a schematic perspective view of a method for automatically caulking a rivet-type electric contact into a contact mounting hole of a spring material.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 die 2 contact insertion hole 3 cylindrical contact material 4 first punch 5′5 ″ frustoconical head 21 recess 22 second punch 23 disk-shaped head 24 rivet type electrical contact 25 recess 26 second punch 27 Light head 28 Riveted electrical contacts

Continuation of the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H01H 11/04 H01H 11/06 H01H 1/00 H01H 1/06

Claims (1)

(57) [Claims] When manufacturing a rivet-type electrical contact, a depth of 0.2 to 0.2 mm is provided at the periphery of an opening of an insertion hole of a cylindrical contact material.
A cylindrical contact material is inserted into the insertion hole of a die having a concentric recess with a large diameter of 0.6 mm, and then a frustoconical head is preformed by a first punch, and then a rear end surface is formed. A method of manufacturing a rivet-type electrical contact, wherein the disk-shaped or thin-shaped head is finish-formed by a flat second punch or a second punch having a truncated cone-shaped concave portion on a tip surface.