JPS5936901A - Contactor for 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] The present invention relates to a contact for a variable resistor.

The contact of a variable resistor has a structure in which the contact part of the contact moves over the resistance element and changes the resistance value by moving phase separation. Conventionally, the contact of the variable resistor has a structure in which the contact part of the contact moves over the resistance element and changes the resistance value by moving phase separation. The contact point was fixed to the tip of a copper plate spring by press-fitting or adhesive, and the carbon contact point moved over the resistive element.

However, in the former case, a metal oxide film is formed on the tip of the contact or on the surface of the resistance element to which abrasion powder from the contact adheres.

There is a type of 7ya in which the rate of change in resistance increases. Since the latter is made of carbon fibers, the rate of change in resistance is extremely small, but there is a drawback in that an assembly process is required to press fit or adhere the contact to the leaf spring, resulting in high costs. In order to reduce the assembly man-hours required for attaching the carbon contacts to the leaf springs, a method of fully press-fitting the carbon contacts to the leaf springs using an automatic machine is being considered, but the carbon contacts are 2111+1φ×2nun11:J,
There are problems such as the fact that the bottom is very small, and the accuracy of the hole size of the leaf spring into which it is press-fitted and the outer diameter size of the plate spring must be strictly controlled. Another option is to integrally mold the carbon contacts into the holes of the leaf springs at the same time as molding them, but carbon contacts require a process of firing to approximately 1000°C after molding, and they cannot withstand this firing temperature and retain their leaf spring properties. I can't find any materials available.

An object of the present invention is to provide a contact for a variable resistor that solves these problems.

Inventor Tate discovered that a contact made by baking a conductive paste, which is a member having the same properties as a carbon contact, onto a leaf spring at low temperature has a small resistance change rate and is easy to assemble.

The present invention relates to a contact for a variable resistor, which includes a contact having a conductive paste baked onto the tip of a leaf spring.

The conductive paste in the present invention mainly contains a mixture of a resin as a baking material, graphite powder as a conductive material, and a solid lubricant such as molybdenum disulfide. The resin may be a thermosetting resin. There are no restrictions on the graphite powder, but one with good lubricity is preferable because it can also serve as a solid lubricant.

The viscosity of the conductive paste is appropriately adjusted by adding molten silicon 11 or the like. Further, in order to improve electrical conductivity, silver powder, copper powder, etc. may be added as needed.

The leaf spring may be a conventional leaf spring made of Rinyoido.

For example, a conductive paste is injected as required into a contact holding hole provided at the tip, formed into a predetermined shape using a mold, and then heated and baked.

Next, a conventional example and an embodiment will be explained with reference to the drawings.

Fig. 1 shows the structure of a conventional contact using a carbon' contact, and Fig. 2 shows the structure of a contact using a conductive paste, which is an embodiment of the present invention. ,(
b) is a front sectional view.

In the figure, 1 and 3 are leaf springs, 2 is a carbon contact, and 4
is a conductive paste contact, and shows the state in which the conductive paste is fixed to the tip of the contact.

In FIG. 3, a contact holder 7 at the tip of a leaf spring is fixed on a sliding mold 8 for a conductive paste contact, and a spray nozzle 6 containing a conductive paste 5 is lowered from above.
The conductive paste 5 is injected into the hole 10 of the contact holding part 7.

The injected conductive paste 5 forms a convex part of the contact point by the depression 9 of the sliding part mold 8 as shown in FIG.

The tetraelectric paste used in this example consisted of 80 layers of epoxy resin and a curing agent (manufactured by Hodogaya Chemical Co., Ltd., trade name: DAM).
) It is a mixture consisting of 10 times a day of natural graphite, 5 times a day of natural graphite, and 5 times a day of molybdenum disulfide. After this, injection nozzle 6
, take out the leaf spring with the conductive paste, place it in a thermostat, and heat it at 170±10°C for 4 hours to bake the conductive paste onto the leaf spring.

A 7ca contactor obtained in Example L, a contactor using a conventional gold-plated contact, and a contactor using a conventional carbon contact were each assembled to a variable resistor, and a sliding test was conducted to determine the number of times of sliding. When the resistance change rate was determined, as shown in Fig. 5, the contactor according to the present invention had l1IqI
It can be used many times.

Since the contacts of the present invention are made of conductive paste, they can be easily attached to leaf springs compared to conventional contacts using carbon contacts, and therefore manufacturing costs can be reduced. Also, the performance is comparable to that of conventional carbon contacts.

[Brief explanation of the drawing]

Figure 1 shows a contact using a conventional carbon contact (a)
2 is a plan view, (b) is a front sectional view, and FIG. 2 is a contact using a conductive paste contact according to an embodiment of the present invention.
1 is a plan view, fbl is a front sectional view, and FIGS. 3 and 4 are partially enlarged front sectional views showing a state in which the conductive paste is fixed to the tip of the leaf spring of the contactor shown in FIG. 2. Explanation of symbols l...Plate spring 2...Carbon contact 3...
・Plate spring 4...4'4 paste contact 5・
... Conductive paste 6 ... Spray nozzle 7 ... Contact holder 8 ... Sliding part mold 9 ... <Indentation
1o...hole 1st (¥) !f32 Figure ((L)
(OL) ¥, 3 mouths
44 Oral Procedures Amendment (Method) % Formula % Showa ÷ 1157 Patent Application No. 130119'=J2, Name of Invention Contactor for Variable Resistor 3, Relationship with Nagisa/Kyu'' (f) Name of Patent Applicant Sen!
445 + Hitachi Chemical J: Co., Ltd. Column 7 of the brief explanation of drawings in the t1 specification, content of amendments + 1) From page 5, line 19 of the specification of the present application to page 6, line 1 [and...・It is. Figures 3 and 4 are partially enlarged front cross-sectional views showing the state in which the conductive paste is fixed to the plate plate of the contact shown in Figure 2, and Figure 5 shows the sliding surface of the contact. This is a graph showing the dynamic test results.''that's all

Claims (1)

[Claims] 1. A contact for a variable resistor, which has a contact point a with conductive paste baked on the tip of a leaf spring.