JPS61159706A - Small variable resistor - 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 Industrial Application) The present invention relates to a small variable resistor used in various electrical devices.

(Structure of conventional example and its problems) A conventional small variable resistor will be explained with reference to FIGS. 1 and 2. These figures are a perspective view of a resistor substrate, a terminal, and a semi-tubular rivet that fastens the two, which are components of a conventional small variable resistor, and a cross-sectional view of the fastening portion.

In FIG. 1, a resistor substrate 1 made of phenol resin or the like has a resistor element 1b having electrode portions 1a at both ends formed on its upper surface, and a shaft portion of a semi-tubular rivet 2, which will be described later, in the center of the electrode portion 1a. A rivet hole 1c is formed through which the rivet 2a is inserted.

The semi-tubular rivet 2 has a head 2b and a caulking hole 2C at the tip of the shaft 2a formed by header processing, as shown in FIG. 1(b), and a rivet seating surface 2d.
is used so as to be in electrical contact with the electrode portion 1a.

The terminal 3 has a terminal portion 3a at its tip and a rivet hole 3b formed at the head of the main body into which the shaft portion 2a of the semi-tubular rivet 2 is inserted.

FIG. 2 is a partial cross-sectional view of the above-mentioned resistor board 1 and terminal 3 fastened together using a semi-tubular rivet 2. The semi-tubular rivet 2 is inserted from the direction of the electrode part 1a of the resistor board 1, and the crimping tool is used. The resistor substrate 1 and the terminal 3 are fastened together by caulking the tip thereof, and the electrode portion 1a and the terminal 3 are electrically connected.

On the other hand, as variable resistors become smaller, the area of the electrode part 1a becomes smaller, and as semi-tubular rivets 2 and terminals 3 also become smaller, it becomes difficult for customers to solder the variable resistor or use it. Due to the influence of the environment in which the electrical equipment is used, the resistor board 1 shrinks, causing the resistor board 1 to shrink.
There was a problem in that the contact state between the electrode portion 1a and the seat surface 2d of the semi-tubular rivet 2 became unstable, and the electrical connection state accordingly became unstable.

(Objective of the Invention) The present invention solves the above-mentioned drawbacks, and has excellent electrical contact between the electrode portion of the resistor substrate and the seating surface of the semi-tubular rivet, and always provides stable characteristics even when downsized. The purpose is to provide a small variable resistor.

(Structure of the Invention) The present invention uses a semi-tubular rivet in which a plurality of protrusions are provided on the seat surface of the rivet that contacts the electrode portion of the resistor element, and fastens the resistor board and the terminal, thereby achieving the above-mentioned As the protrusion of the seat surface slightly bites into the electrode portion, the contact pressure between the two increases, and a stable electrical contact state is always obtained.

(Explanation of Embodiments) Embodiments of the present invention will be explained with reference to FIGS. 3 and 4.
The resistor substrate and terminals constituting the small variable resistor according to the present invention are the same as those of the conventional example shown in FIG.

FIG. 3 is a perspective view of a semi-tubular rivet 4 according to the present invention for fastening the resistor substrate 1 and the terminal 3. Four projections 4b are formed on the seat surface 4a of the rivet.

FIG. 4 is an enlarged sectional view showing the fastening portion between the resistor substrate 1 and the terminal 3 according to the present invention, in which the protrusion 4b of the semi-tubular rivet 4 bites into the electrode portion 1a formed on the upper surface of the resistor substrate 1. It is concluded in the state.

In addition, as an example similar to the present invention, there is a method in which an eyelet-shaped tubular rivet is formed by drawing a metal plate and a ring-shaped projection is provided on the seat surface. It is impossible to apply to rivets. However, according to the present invention, since the semi-tubular rivet is formed by eight-point machining, it is possible to form the protrusion on the seat surface even with an extremely small diameter semi-tubular rivet.

[Brief explanation of drawings]

FIG. 1(a) is a perspective view of the resistor board and terminals that make up a conventional small variable resistor, FIG. 1(b) is a perspective view of a semi-tubular rivet that fastens these two together, and FIG. FIG. 3 is a perspective view of a semi-tubular rivet used in a small variable resistor according to the present invention; FIG.
The figure is an enlarged sectional view of a fastening part using the semi-tubular rivet of FIG. 3. 1...Resistor board, la...electrode part, lb...
Resistor element, le, 3b... rivet hole, 2, 4...
・・Semi-tubular rivet, 2a・shaft part, 2b・
...Head, 2c...Clinching hole, 2d, 4a...
・Seat surface, 3...Terminal, 3a...Terminal part, 4b
···protrusion. Patent applicant Matsushita Electric Industrial Co., Ltd. Figure 1 Factor 2

Claims (1)

[Claims] An electrode part with a rivet hole in the center, a resistor board with resistor elements provided at both ends, and a terminal with a rivet hole in the terminal are inserted by inserting a rivet into the rivet hole from the electrode side. A small variable resistor constructed by caulking and fastening, characterized in that the rivet is a semi-tubular rivet having a plurality of protrusions on a seat surface formed by processing a header.