JPS5954119A - Composite contact - 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 (1) Description of the technical field to which the invention pertains The present invention relates to a composite contact, and more particularly to a composite contact constructed at an extremely low cost with a significant reduction in the amount of precious metals such as silver.

(2) Description of the prior art Conventionally, in order to obtain the desired opening/closing performance, switch contacts have generally been manufactured using header processing using rivet-shaped contacts with a large diameter head portion made of silver or other precious metal. was used as a fixed contact (see Figures 7 and 8).

FIG. 7 is a perspective view of a conventional composite contact, and FIG. 8 is a sectional view of the composite contact attached to a switch. In the figure, 11 is a composite contact consisting of a head 12 and a lower neck portion 13, and the head 12 consists of a noble metal part 12a such as silver and a metal part 12b such as copper. 15 is the switch body, 16
17 indicates a movable contact, and 17 indicates a terminal.

However, in the case of such a rivet-shaped composite contact 11 made by crimping silver and copper by header processing,
From the relationship of the joint strength of that part, the ratio of the diameter of the contact neck lower part 13 to the diameter of the head 12 is such that the head diameter is in the range of 1.6 to 2 times d to the lower neck diameter d. If it was found to be appropriate and necessary, it was subject to that restriction. For example, the desired under-neck diameter d = 9.5 mm (The under-neck diameter is related to the strength with which the terminal is crimped and fixed, and as it becomes thinner, the strength decreases. Practical experience has shown that around 2.5 mm is appropriate. ), it is necessary to make the head diameter D=4 mm or more.

Therefore, the diameter of the silver 12a part in the head naturally becomes large, and the amount of silver used becomes extremely large (the amount of silver (volume) changes greatly depending on the size of the diameter M. In other words, the radius The major drawback was that the amount differs in proportion to the square of the change in .

Incidentally, the conventional rivet-shaped composite contact 11 shown in the seventh factor is manufactured by cutting a silver wire and a copper wire with a diameter equal to or slightly smaller than the diameter under the neck and processing the header. However, this conventional rivet-type composite contact has a major drawback in that it uses a large amount of silver, making the contact expensive.

Therefore, in the past, for the purpose of lowering costs, instead of composite contacts with precious metals such as silver on the head, rivet-shaped contacts made entirely of copper or the like were manufactured, and some of them were plated with silver. It was put into practical use. However, this silver plating is not suitable for switching large currents and is limited to small currents.Furthermore, as the contacts are repeatedly opened and closed, the silver plating wears out, resulting in an increase in contact resistance. As a result, the period during which the desired performance can be obtained is limited, resulting in extremely short service life and low reliability, which are major drawbacks.

(3) Detailed Description of the Invention The present invention has been made in order to eliminate the above-mentioned drawbacks inherent in the conventional technology.Therefore, an object of the present invention is to significantly reduce the amount of precious metals such as silver and to achieve an extremely low price. The purpose of this invention is to provide a new composite contact point that can be configured as follows.

(4) Structure of the Invention In order to achieve the above object, the composite contact according to the present invention is a composite contact made of a conductive material such as copper having a noble metal portion such as silver on the head, and a diameter under the contact neck and a noble metal portion. The diameter of the head having the part is formed to be approximately the same, and a large-diameter collar is integrally formed between the head and the under-neck part.

(5) Detailed Description of the Invention Next, preferred embodiments of the present invention will be specifically described with reference to the drawings.

FIG. 1 is a front view showing an embodiment of a composite contact according to the present invention, and FIG. 2 is a sectional view of the main part of a switch using the composite contact. In the figure, reference number 1 indicates a composite contact according to the present invention, and the composite contact 1 includes a head 2 consisting of a noble metal part 2a made of silver or the like and a metal part 2b made of copper or the like, and a metal part 2. The neck part 3 is formed of the same material as the metal part 2b and the neck part 3, and the collar part 4 is disposed between the metal part 2b and the neck part 3 and is made of the same material as the metal part 2b and the neck part 3 and is integrally formed therewith. It is configured. The noble metal part 2a is joined onto the metal part 2b. Visit, 5
5a is a switch body, 5a is an insertion hole, 6 is a movable contact, 7 is a terminal, and 8 is a screw.

As shown in FIG. 1, a composite contact 1 made of a conductive material such as copper and having a noble metal portion 2a such as silver on the head is formed by a diameter d of the neck/lower part 3 of the contact and a diameter D' of the head 2. They are formed almost equally. A large-diameter collar 4 is formed between the head 2 and the lower neck 3. Note that the lower part of the neck is slightly tapered, but the relationship between this part and the hole of the terminal to be fitted is slightly press-fitted to ensure that the contact and terminal are fixed and the electrical This is to make the connection even more reliable.

As shown in FIG. 2, the lower neck 3 of the composite contact 1 of the present invention is inserted from above into the insertion hole 5a formed in the switch body 5, and the hole of the terminal 7 is fitted into the tip of the lower neck. Tighten the tip. This ensures that the collar 4 formed on the contact and the terminal 7 are firmly fixed to the switch body 5. In the end, due to the large-diameter collar 4, the diameter of the head 2 of the contact does not need to be large unlike the conventional one, and the diameter of the head 2 of the contact point does not need to be large as in the case of the conventional one. 2.
Even if it is about 7rrlrr1, there will be no problem.

In short, the diameter of the noble metal portion 2a of the head 2 is the same as that of the movable contact 6.
It only needs to be set in abutting relationship with the contact point, and it can be made considerably smaller than conventional rivet-type contacts. For example, if the head diameter of a conventional rivet-shaped contact is 4 mm and the head diameter of the present invention is 2.7 ROM, the amount of silver used is proportional to the square of the change in radius. The amount (volume) is reduced, and in the end, the amount of silver used can be reduced by more than 50 inches, or less than half of the conventional amount.

Also, the head diameter is smaller than before (for example, 4mm-+
2.7 mm), if the diameter of the collar 4 formed at the contact point is set to 4 mm, the diameter under the neck can be made the same as the conventional one (for example, 9.5 mm).

Therefore, it can sufficiently withstand the screw tightening torque and pushing force applied to the terminal 7 as shown in Fig. 2, and there is no need to worry about the strength decreasing or the terminal falling off. This will significantly reduce the amount of silver used.

FIGS. 3 and 4 show an example of the manufacturing process until the final shape of the composite contact according to the present invention is made.

In the example shown in Figure 3, the silver wire material and the copper wire B (about 1.5 mm diameter) are cut to a predetermined length in step (1), and the silver wire A is placed on top of the copper wire B. Overlap them and insert them into the die. In step (2), header processing is performed and first preforming is performed to crimp the silver and copper wires, and to make the diameter of the wires slightly thicker. At step (3), header processing is performed.
A large diameter tsuba is formed by preforming, and the diameters of the head and under the neck are further increased to approximate the final shape.

At step (4), finishing molding is performed by header processing to complete the composite contact 1 in the final shape (for example, head diameter 2.7 mm, collar diameter 4 mm, neck diameter 2.5 mm). In addition,
These steps (1) to (4) are successively performed by the header processing device.

The example shown in FIG. 4 is a partial modification of the example shown in FIG.

In step (1), a copper wire (about 2.2 mm diameter) is cut into a predetermined length and inserted into a die. In step (2), the copper wire B is first preformed to make it thinner near the top.

Then, a silver wire A cut into a predetermined length having approximately the same diameter (about 1.6 mm) is placed on the narrowed part. (3)
At the step of header processing, second preforming is performed to crimp silver and copper wires, and to thicken the head area. The final shape of the composite contact 1 is then completed through steps (3) and (4) shown in the example of FIG.

FIGS. 5 and 6 show a cross section of an example of the shape of a header machining jig in the final forming stage of header machining to form the final shape of a composite contact according to the present invention. In the figure, 9 represents a die, 9a represents a dowel pin, and 10 represents a punch. In FIG. 5, the four parts forming the collar 4 are provided on the die 9 side, but the difference is that in FIG. 6 they are provided on the punch 10 side.

Although the configuration of the present invention has been described above with reference to one preferred embodiment thereof, this is merely an illustrative example, and the present invention is not limited only by the embodiment described here, but only within its scope. It goes without saying that this includes all modifications and changes. For example, in the present invention, the dimensions (thickness and height) of the flange formed at the contact point are as follows:
It may be set even larger.

(6) Effects of the invention By forming a large-diameter tsuba between the head and the bottom of the neck of a composite contact made of a material such as copper that has a precious metal such as silver in the head, the head diameter can be reduced compared to the conventional one. Compared to the rivet-type contact, we were able to make it much smaller and make it almost the same as the diameter under the neck, which made it possible to significantly reduce the amount of precious metal used to less than half that of the conventional one. It has the remarkable effect of being extremely low cost.

Unlike silver-plated contacts, there is no need to worry about increased contact resistance or shortened lifespan during switching, and by using the composite contact of the present invention, it can also be used for switching relatively large currents. It is possible to provide a highly reliable switch that has a long life, extremely stable opening and closing performance, and is inexpensive.

Moreover, in the terminal crimping method, the strength performance of the fixed portion does not deteriorate at all since there is no need to reduce the diameter under the neck.

The composite contact of the present invention can be manufactured continuously and automatically by header processing, and is extremely suitable for mass production. Also,
Compared to bonding silver or other materials using brazing, there is no variation in the strength of the joints, resulting in high reliability.

[Brief explanation of drawings]

FIG. 1 is a front view showing an embodiment of the composite contact according to the present invention, FIG. 2 is a sectional view of the main parts of a switch using the composite contact shown in FIG. 1, and FIGS. 4) is an explanatory diagram showing an example of the manufacturing process of the composite contact according to the present invention, FIG. 4 (1)
~(3) are explanatory diagrams showing other examples of the manufacturing process of the composite contact according to the present invention, FIG. 5 is a sectional view showing a structural example of a header processing jig used in the present invention, and FIG. A sectional view showing another structural example of a ladder processing jig, Fig. 7 is a perspective view of a conventional rivet-type compound contact, and Fig. 8 is a cross-section showing the main parts of a switch using the compound contact shown in Fig. 7. It is a diagram. 1.11-@・Composite contact, 2.12...Head, 2a. 12a...Precious metal part, lb, 12b...Metal part, 3
．． 13... Neck lower part, 4... Flange part, 5.15・φO switch body, 5B, 15ae*a insertion hole, 6.16
...@Movable contact, 7.1711...Terminal, 8...Screw, 9...Dice, 9aa-Knock bottle, 9b, 10
a... recess for forming the tsuba, 10... punch, A
...Silver wire, B...Copper wire Patent applicant: Japan Switchgear Industry Co., Ltd. Agent: Patent attorney Yutabe Kumagaya-11-1

Claims (1)

[Claims] A composite contact made of a conductive material such as copper having a noble metal portion such as silver in the head, the diameter of the bottom of the contact neck and the diameter of the head having the precious metal portion being approximately equal, and A composite contact point characterized by a large-diameter tsuba integrally formed between the bottom of the neck and the bottom of the neck.