JPS61183820A - Electric 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 Field of the Invention The present invention relates to contacts for electrical equipment such as electromagnetic relays.

<Prior art and its problems> Conventionally, in electrical equipment such as electromagnetic relays, electrical contacts such as a movable contact fixed to a movable contact piece and a fixed contact fixed to a fixed contact piece are used as shown in Fig. 5. A contact base 21 is formed of silver or silver alloy, and this contact base 2
1 is strongly influenced by a corrosive atmosphere, especially a sulfidic atmosphere, and sulfide (Ag*S) is generated on the surface, significantly increasing the contact resistance. Therefore, a contact base is installed on the contact surface 21A. It is known that a layer 22 of a noble metal such as gold or gold alloy, which has better corrosion resistance than the button 21, is formed by plating or cladding.

For example, as shown in FIG. 6, such an electrical contact 20 is made to abut on a contact piece 23 such as a movable contact piece or a fixed contact piece, and is connected to a resistor that conducts current by sandwiching both 20 and 23 with electrodes 24 and 24. By welding, the protrusion 21B protruding from the lower surface of the contact base 21 is melted and fixed onto the contact piece 23 as shown in FIG. On the other hand, the convex portion 21B protruding from the contact base 21 is penetrated,
By caulking this penetrated convex portion 21B, it is fixed onto the contact piece 23.

However, when welding (therefore fixing the electrical contact 20 as in the former case), the height H of the electrical contact 20 may vary depending on the degree of welding of the convex portion 21B and variations in the height dimension of the contact base 21.
l may vary and become drier than the standard cylinder size. Further, even when the electrical contact 20 is fixed by caulking as in the latter case, the height Hl of the electric contact 20 may vary due to variations in the caulking work or variations in the height dimension of the contact base 21.
may change and the standard height H may also become higher.
Each influences the characteristics of the contact mechanism.

Therefore, after the electrical contact 20 is fixed to the contact piece 23, the insularity is adjusted by a forming process. That is, as shown in FIGS. 7 and 8,
Electrical contact 20 having a dimension H1 higher than the reference height Ho
is compressed in the vertical direction by pressing or hammering with a mold (not shown) to form an electrical contact 20 having a reference height H shown in FIG.

However, the electrical contact 20 whose height has been adjusted by the above-mentioned 7 ohming process has a width dimension W of 7 ohms (
The W dimension (W1 in Fig. 5) is also larger, and the contact base 2
The edge portion 2IC around the contact surface 21A of 1 is the noble metal layer 22
It sticks out and is exposed.

In this way, when the electric contact 20 with the exposed edge portion 21C is applied to a loss bar j point mechanism as shown in FIG. An electrical contact 2 in which the edge portion 21C of the electrical contact 20 fixed to the piece 23 faces
Touch 0.

In other words, the contact base 21 is corroded by a corrosive atmosphere.
There is a problem in that contact resistance increases due to contact between the edge portions 21C.

<Purpose of the Invention> The present invention was made to solve the above-mentioned conventional problem, and even after forming treatment for adjusting the cylindrical length, the edge portion of the contact base made of silver or silver alloy is exposed. The purpose of the present invention is to provide an electrical contact configured to prevent

<Configuration and Effects of the Invention> In the electrical contact according to the present invention, the contact surface of the contact base made of silver or silver alloy is coated with a noble metal layer made of gold or gold alloy, and the contact surface of the contact base is coated with a noble metal layer made of gold or gold alloy. It is characterized in that the peripheral edge portion is covered with a noble metal skirt portion extending from the noble metal layer.

Therefore, according to the present invention, like the contact surface of the contact base, the edge portion around the contact surface is covered with the noble metal skirt portion extending from the noble metal layer covering the contact surface. Even if the width of the electrical contact increases due to processing, the edge portion of the contact base is not exposed, so even if the contact surface is twisted, the contact base will not come into contact with the opposing electrical contact.

<Explanation of Examples> Embodiments of this invention will be described below with reference to the drawings.

FIG. 1 is a perspective view showing an embodiment of the electrical contact according to the present invention, and FIG. 2 is a sectional view taken along line 2-2 in FIG. The same reference numerals are used to omit the detailed explanation.

In the figure, the contact base 20 is made of silver or a silver alloy and has a trapezoidal cross section, and the top contact surface 21A is coated with a noble metal 1122 made of gold or gold alloy, and the peripheral edge portion 210 of the contact surface 21A is coated with a noble metal 1122 made of gold or a gold alloy. It is covered with a noble metal skirt portion 22A extending from the noble metal layer 22.

Note that the noble metal layer 22 and the skirt portion 22A are formed by plating or gold cladding.

The electrical contact 20 configured in this manner is fixed to a contact piece 23 such as a movable contact piece or a fixed contact piece by, for example, resistance welding, as shown in FIG. If the height is also high, even if the height is adjusted as shown in FIG. 4 by a forming process using conventional means, the edge part 21C of the contact base 21 will be covered by the noble metal skirt part 22A as before the forming process. Therefore, the edge portion 2 of the electrical contact 20 described in the conventional example
There is no problem of 1C coming into contact with the opposing electrical contact 20. Contact between the tabs and the noble metal layers 22 or between the noble metal layers 22 and the noble metal skirt portion 22A can be obtained.

Although the above embodiment describes a trapezoidal contact base 21, the present invention is not limited to the above embodiment, and is naturally applicable to contact bases 21 of irregular shapes such as cylindrical and prismatic shapes. can.

Further, although an example has been described in which only the edge portions 21C on both sides of the contact base 21 are covered with the noble metal skirt portion 22A, the edge portions over the entire circumference of the contact base 21 may be entirely covered with the noble metal skirt portion 22A. .

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing one embodiment of the electrical contact according to the present invention, and FIG.
; rT side view, FIG. 3 is a side view showing the state fixed to the contact piece, FIG. 4 is a cross-sectional front view of the electrical contact with height adjustment, FIG. 5 is a perspective view of the conventional electrical contact, FIG. 6 is a side view showing an example of fixing means for the contact piece, FIG. 7 is a side view showing a state of fixing to the contact piece, FIG. 8 is a side view showing another example of fixing to the contact piece, and FIG. FIG. 10 is a perspective view showing an example of an electrical contact formed to a standard height, and FIG. 10 is a perspective view showing an example of application of the electrical contact. 20... Electrical contact, 21... Contact base, 21A...
- Contact surface, 21C...edge portion, 22...prize metal layer, 22A...precious metal skirt portion. Figure 1 Figure 85 Figure 6 Figure 7

Claims (2)

[Claims] (1) A contact surface of the contact base is covered with a noble metal layer, and an edge portion around the contact surface is covered with a noble metal skirt extending from the noble metal layer. contact. (2) The electrical contact according to claim 1, wherein the contact base is made of silver or a silver alloy, and the noble metal layer is made of gold or a gold alloy.