JPS62219603A - Miniature 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 electronic devices.

(Prior art) An example of a conventional small variable resistor is shown in Figures 4 and 5.
This will be explained using figures. In FIG. 4, a resistor element 1b having a silver electrode portion 1a at both ends is formed on the main surface of a resistor substrate 1, and a terminal to which an outer terminal 2 is attached to the center of the silver electrode portion 1a. a hole 1c, a notch 1d in which the protrusion 3a of the middle terminal 3 is engaged between the two silver electrode parts 1a;
A central hole 1e into which the eyelet portion 3b of the middle terminal 3 is inserted is formed in the center of the board. The outer terminal 2 includes a terminal part 2a which is inserted into the terminal hole IC of the resistor board 1, the part protruding onto the board is fixed by caulking, etc., and is electrically connected to the silver electrode part 1a by soldering, etc. is formed. The middle terminal 3 has a resistor substrate 1. An eyelet portion 3b that is inserted into the center hole of each of the seat plate 4 and the slider 5, and a protrusion 3 that engages with a stopper 68 of the cap 6 at the end.
a stands vertically, and the terminal portion 3C is formed so as to stand vertically in the opposite direction.

The seat plate 4 is made of synthetic resin and has a central hole 4a in the center through which the eyelet portion 3b of the inner terminal 3 is inserted. Slider 5
has a central hole 5a in the center through which the eyelet portion 3b of the inner terminal 3 is inserted, and around the central hole 5a there is an arm portion 5b that contacts the resistor element 1b with appropriate pressure and a convex formed inside the cap 6. A notch 5c is formed to engage with the portion 6b. Cap 6 is.

Made of synthetic resin, there is a rotation adjustment groove 6C on the upper surface, and a cylindrical portion 6d inserted into the inner diameter portion of the eyelet portion 3b of the inner terminal 3 at the center of the lower surface.
To further explain with reference to FIG. 5 showing the inside of the cap, the inside of the cap 6 includes a stopper 68 against which the protrusion 3a of the inner terminal 3 comes into contact, and a convex portion that engages with the notch 5c of the slider 5. 6b is provided.

Next, the assembly method will be explained. First, the external terminals 2 are assembled onto the resistor substrate 1. Next, resistor substrate 1.
Stack the seat plate 4 and slider 5 in this order, and insert each center terminal hole 1.
Insert the eyelet part 3b of the middle terminal 3 into e, 4a and 5a,
The slider 5 is assembled so that the slider 5 can be freely rotated by caulking the part protruding from the upper surface of the slider 5. Furthermore, insert the cylindrical portion 6d of the cap 6 into the inner diameter portion of the eyelet portion 3b of the inner terminal 3,
One assembly is completed by caulking the portion protruding from the lower surface of the middle terminal 3 so that the cap can rotate freely.

In the conventional stopper mechanism, the stopper 6 of the cap 6
8, a mechanism is formed in which the protrusion 3a of the middle terminal 3 contacts and rotation is restricted. FIG. 6 shows a state in which the cap 6 is rotated and the stopper mechanism is activated. In order to stabilize the stop strength, it is necessary that when the stopper 6a and the protrusion 3a abut, the area S of the side surface of the protrusion 3a is entirely included within the plane of the stopper 68.

(Problem to be solved by the invention) □ However, the protrusion 3a of the inner terminal 3a may tilt inward due to variations in bending process or unexpected deformation during the assembly process, and the contact area between the stopper and the protrusion may be reduced. There is a problem that S becomes extremely small, and as a result, the stop strength becomes extremely small, and the number of parts and assembly steps are also large, so that the price requested by the user cannot be satisfied.

31 The present invention solves the above-mentioned problems, and provides a small variable resistor that constitutes a stable stopper mechanism with a smaller number of parts and fully satisfies the user's desires.・(Means for solving the problem) Covering the resistor element and having an arc-shaped through groove in the top plate,
A rotatable brush is provided on the cover, which also serves as the live power section. This brush has a sliding arm that slides on the resisting element at one end, and a hole at the other end at a position corresponding to the through groove of the cover.

(Process m1) By inserting a protrusion such as a screwdriver into the hole of the brush through the through groove and moving it along the through groove, the brush can be rotated and set to the desired resistance value. Both ends of the projection can be used as stoppers for movement of the projection.Shadow (Example) Hereinafter, an example will be described in detail with reference to the drawings.

FIG. 1 shows an embodiment of the present invention, where 11 is a resistor substrate on which a resistor element 14 is formed and a lead-out terminal 16 is connected to the resistor element 14, and 12 is a live current part. A metal cover 13 which also serves as a brush is rotatably attached to the cover 12 and has a sliding arm 13b at one end that slides on a resistor element formed on a resistor substrate. An arc-shaped through groove 12a is provided in the top plate portion of the cover 12, and the brush 1 is aligned with the through groove 12a.
3 is provided with a hole 13a.

Next, details of each part will be explained. FIG. 2 shows the resistor board 11
and a cover 12 to be placed over it.

First, a resistor element 14 is formed on the upper surface of the resistor substrate 11, and lead-out terminals 16 are connected to electrode portions 15 provided at both ends of the resistor element 14, respectively.

The outer periphery of the board includes a notch llb into which the mounting leg i2b of the cover 12 is locked, and an inner terminal 1 extending from the cover 12.
It has a notch 11c through which 2c passes.

The cover 12 is made of a metal material, and has a mounting leg portion 12b and a middle terminal 12c integrally formed on a rounded outer peripheral portion. There is an arc-shaped through groove 1 in the top plate part of the cover 12.
2a is formed. As shown in FIG. 3, inside the cover 12, a cylindrical part 12d for holding the brush 13 is provided at the center, and a central hole 13c of the brush 13 is fitted into this cylindrical part 12d. The brush 13 is rotatably attached by caulking the tip of the cylindrical portion 12d. A sliding arm 13b that slides on the resistor element 14 extends from one end of the brush 13, and a hole 13a is provided at the other end at a position corresponding to the through groove 12a of the cover 12. There is.

In this embodiment configured as described above, the first protrusion 17a of the special screwdriver 17 shown in FIG.
By inserting the second protrusion 17b into the hole 13a of the brush 13 through the through-hole 12a of the cover and rotating it, the contact position on the resistor element 14 by the sliding arm 13b is changed and the desired resistance value is set. be able to. Further, since the movement of the second protrusion 17b of the special screwdriver is stopped at both ends 12f of the through groove 12a, these ends 12f serve as reliable stoppers. Furthermore, the number of parts is reduced and assembly work is greatly simplified.

(Effects of the Invention) As explained above, according to the present invention, the rotation of the brush can be reliably stopped by the protrusion of a screwdriver or the like inserted into the hole of the brush and the end of the through groove of the cover. The stopper mechanism is structurally robust, the number of parts is reduced, and assembly is easy, resulting in a significant reduction in manufacturing costs.

[Brief explanation of drawings]

FIG. 1 is a sectional view of one embodiment of the present invention, FIG. 2 and FIG.
4 is an exploded perspective view of a conventional small variable resistor, FIG. 5 is a diagram showing the inside of the cap, and FIG. 6 is a diagram showing the configuration of each part of the same embodiment. FIG. 3 is a sectional view showing a conventional stopper mechanism in a working position. 11...Resistor board, 12...Cover, 12a
...through groove, 12c...middle terminal, 13...brush, 13a...hole, 13b...sliding arm, 1
4... Resistor element, 15... Electrode, 16...
Pull-out terminal, 17...Special screwdriver, 17a, 1
7b...Protrusion. Fig. 1 17b...-Trap start Fig. 2 2f

Claims (1)

[Claims] a resistor substrate on which a resistor element is formed; a cover that covers the resistor element portion of the resistor substrate and has an arc-shaped through groove in its top plate portion and also serves as a live current portion; and a top plate of the cover. The brush is rotatably held inside the part, and includes a sliding arm that slides on the resisting element at one end, and a brush having a hole at the other end at a position corresponding to the through groove of the cover. A protrusion such as the like is inserted into the hole of the brush through the through groove, and the brush is rotated by moving it along the through groove to set the desired resistance value, and both ends of the through groove are inserted into the hole of the brush. A small variable resistor characterized by a stopper against movement of a protrusion.