JPS5937535B2 - electric sliding contact - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electric sliding contact used in mechanical parts such as connectors and switches that involve sliding contact.

Electrical contacts such as conventional connectors generally use a Cu alloy spring material as the base metal, and N is applied on this base metal.
Contacts plated in the order of i, Au (or Ni,
, Ag, etc.) are used.

As a method for electrically connecting these contacts, for example, a contact pair consisting of a plug and a jack has the same plating surface.

For such contact pairs, recently, contacts have been used in which Pd, which is cheaper than Au, is used and a base metal is plated with Ni, Pd, and Au in this order.

However, since it uses Au, it has the disadvantage of being expensive. To eliminate this drawback, N
Although there is an i-Pd-In multilayer plated contact, this contact has a drawback that when the same contact is used in combination as a sliding contact in a connector, the coefficient of friction is high and therefore the wear is large. In addition, there are contacts in which Ni, then Pd are plated on the base metal, but this contact has a high friction coefficient in the same type of sliding contact as the Ni-Pd-In multilayer plated contact. , which has the disadvantage of high wear.

The present invention provides Ni-Pd or Ni-Pd-
This is an attempt to eliminate the drawbacks of In-plated electrical contacts.
To provide a new electric sliding contact which has excellent contact performance (coefficient of friction, wear) by combining a pair of contactors such that one surface of the contactor is made of Pd and the other surface is made of Indium. be.

The present invention aims to improve wear resistance by bringing different materials into sliding contact.

In general, contact between different materials often causes less wear than contact between similar materials.

It is influenced by whether the materials on the surface of the contact point are likely to be alloyed with each other or the state of formation of the surface film. The configuration of the present invention is such that excellent contact performance is obtained by a combination of a contact P whose outermost surface is plated with Pd and a contact I whose outermost surface is plated with In. That is, to explain the plug and jack of the connector as an example, the present invention is a combination in which P is used as the plug and I is used as the jack. This means that, like a plug, the surface of the contact x, which is substantially larger than that of a jack, is plated with Pd, while the surface of the contact Y, whose sliding track is relatively small, is plated with In. The present invention is a dissimilar contact method consisting of plating. The reason why the combination contact of the present invention is superior to other combinations, such as the reverse combination contact of the present invention, is as follows? I can explain. Since contact Y has a smaller sliding track than contact X, Y has a larger temperature rise at the contact point than X.

Therefore, In, which has a low melting point, interdiffuses with the underlying Pd at a relatively early stage after the start of sliding, and the surface becomes In.
-Pd alloyed. Therefore, substantial contact is a contact phenomenon between the Pd of the X contact and the In--Pd alloy of the Y contact, resulting in excellent contact performance. On the other hand, when the combination of the present invention is reversed, that is, the surface of the contact x with the larger sliding track is plated with In and the surface of the contact Y with the smaller sliding track is plated with Pd, the x contact Since the temperature rise of the indium is relatively small, the In on the outermost surface is slightly oxidized before diffusion with the lower layer occurs.

Since this In oxide is harder than metal 1n, it acts like an abrasive during sliding contact, increasing the coefficient of friction and therefore increasing wear. This combination has poor contact performance. In other words, in a sliding contact made of different amounts of materials, the new electrical contact according to the present invention is a combination in which the surface of the contact with a larger sliding contact area is made of Pd and the surface of the contact with a smaller sliding contact area is made of In.

FIG. 1 is a diagram showing an example of a cross-sectional configuration of a contactor used in an embodiment of the present invention. In FIG. 1, a is given as the contact X of the present invention, and b is given as the contact Y.

In FIG. 1, reference numeral 1 indicates a base metal, and in all the examples, phosphor bronze wire (PBW3-H) is used.

2 is Ni plated and has a thickness of 1.5 μm.

3 is plated with Pd and has a thickness of 0.5 μm.

Further, 5 is indium plated and has a thickness of 0.5 μm. Figure 2 shows the number of sliding contacts and the friction at that time for a total of four sliding contacts in which contacts X and Y are of the same type, different types, and in the case of different types, they are rearranged on the plug side and jack side respectively. FIG. 3 is a diagram showing changes in coefficients.

In addition, in this sliding contact, the contact load is 300y, the sliding length is 3mm, and the number of times of sliding is 2.
There are times. The curve numbers in the figure are based on the combinations in Table 1. From FIG. 2, it can be seen that, compared to the combinations 1, 3, and 4, the friction coefficient of 2 is very small and stable, and the combination of 2, that is, the combination of the present invention, is the most excellent. Table 2 shows the results obtained by microscopic observation of the size of the wear marks on the contact part of the jack side contactor after 200 slidings according to the example shown in Fig. 2, and the diameter of the wear marks is large. This indicates that the contactor has greater wear. As is clear from the above examples, the second embodiment of the present invention exhibits much superior contact performance than the conventional Pd-based contact 1, and the superiority of the combined contact of the present invention can be understood.

Note that the contact resistance in Table 1 was 20 mΩ or less for any of the combinations 1, 2, 3, and 4, indicating stable contact resistance.

According to the present invention, since expensive Au on the outermost surface can be replaced with inexpensive In, material costs can be reduced.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram of the sample used in the example, and FIG. 2 is a diagram showing the relationship between the number of sliding movements and the coefficient of friction.

Claims (1)

[Claims] 1. In electric sliding contacts that are combined so that the sliding distances of a pair of opposing contacts are different, the surface of the contact that has a large sliding distance during sliding contact is essentially made of Pd, while the surface of the contact that has a large sliding distance during sliding contact is An electric sliding contact characterized in that the surface of the small contact consists essentially of In.