JPH0719122Y2 - Assembled potentiometer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a built-in potentiometer having stable performance by eliminating variations in contact pressure of a sliding contact (brush) of the potentiometer.

[Conventional technology]

FIG. 3 is a longitudinal sectional view showing a conventional potentiometer.

In the potentiometer A, a substrate 39 having an annular resistance circuit 38 is fixed inside a resin case 37, and a central shaft 41 is rotatably provided via a cylindrical bearing 40.
A rotary body 44 having an output gear 42 at the front end and a sliding contact (brush) 43 for the resistance circuit 38 at the base end, respectively, being fixed by press fitting, and an input gear 45 is provided on the outer periphery of the rotary body 44. Is.

Here, at both ends of the central shaft 41, the output gear 42 and the rotating body 44
Serrations 46 and 47 for press-fitting and fixing are formed. In addition, as shown in the arrow B view of FIG. 3 in FIG.
a is fixed with a rivet 48 or the like, and a brush portion 43c is welded to the tip of a conductive spring piece portion 43b that obliquely protrudes from the bottom plate portion 43a. It slides against 38 and changes the resistance value. Here, the contact pressure (contact pressure) of the contactor 43 with respect to the resistance circuit 38 must always be appropriate, otherwise accurate resistance value cannot be obtained due to poor contact of the brush portion 43c or the like.

However, in the above conventional example, when the output gear 42 and the rotating body 44 are press-fitted to the central shaft 41 via the tubular bearing 40 in the opposing direction, if the press-fitting is too strong, the cylinder If the rotating body 44 is pressed against the ring-shaped bearing 40 to prevent smooth rotation and the press-fitting is too weak, the board
There is a problem that the contact pressure of the contactor 43 is weakened because the gap L between the 39 and the rotating body 44 is too wide. In addition, for that reason, much effort and labor was required for press-fitting (contact pressure) management.

[Problems to be solved by the device]

In view of the above-mentioned points, the present invention has an object to provide a potentiometer in which the contact pressure between the resistance circuit and the contactor is always appropriate and does not require contact pressure management.

[Means for Solving the Problems]

In order to achieve the above-mentioned object, the present invention comprises a substrate on which an annular resistance circuit is formed, and a rotating body which is provided with a contactor for the resistance circuit so as to project toward the inner wall side and is rotatable opposite to the substrate. In the potentiometer provided, a central shaft or a cylindrical bearing that slidably supports the rotating body in the rotational direction and the axial direction is fixed to the substrate side by penetrating the rotating body. A step portion having an annular seating surface with respect to the inner wall side of the rotating body is formed in the middle portion of the rotating body, and the rotating body is supported by the central shaft or the bearing on the outer wall side of the rotating body so that the rotating body faces the substrate. The inner wall side is brought into contact with the seat surface by being urged by.

[Action]

The urging force of the spring member causes the rotating body to come into contact with the central shaft or the stepped portion of the bearing, so that the distance between the rotating body and the substrate is always kept constant. As a result, the contactor always contacts the resistance circuit with a constant contact pressure.

〔Example〕

FIG. 1 is a longitudinal sectional view showing an embodiment of an assembled potentiometer according to the present invention.

The potentiometer A ₁ comprises a resin case 1 and a metal center shaft 2 fixed by insert molding.
A substrate 4 having an annular resistance circuit 3 inside the case 1.
The rotary body 6 having the contact 5 for the resistance circuit 3 on the inner wall 6a side is rotatably inserted to the central shaft 2, and the outer wall 6a of the rotary body 6 and the central shaft 2 ring groove 7
The wave washer 9 as a spring member is interposed between the retaining ring 8 and the retaining ring 8 fitted in the base plate 4, and the rotating body 6 is biased toward the substrate 4.

Here, a boss portion 11 is formed so as to project at the end edge of the center hole 10 of the rotating body 6, and the projecting end of the boss portion 11 is rotatably abutted on the seat surface 12a of the step portion 12 of the center shaft 2. There is. Therefore, the rotating body 6 axially biased by the wave washer 9 is positioned by bringing the boss portion 11 into contact with the step portion 12 of the central shaft 2,
It is possible to always keep a constant distance between the rotor 6 and the rotating body 6, that is, a contact pressure between the resistance circuit 3 and the contact 5.

An annular lip wall 13 is integrally provided on the outer periphery of the rotating body 6 so as to fit into the peripheral wall 14 of the case 1 so as to prevent dust from entering the brush chamber 15. A ring-shaped input gear 16 is provided on the outer side of the nuclear annular lip wall 13.
In the figure, 17 is a connecting body, and an output pinion gear 18 is connected to the rotating body 6. Reference numeral 19 is a flat washer, and 20 is a lead wire connected to the resistance circuit 3. The tip of the central shaft 2 is locked to a wall portion or the like (not shown).

FIG. 2 is a vertical sectional view showing another embodiment of the assembled potentiometer according to the present invention.

The potentiometer A ₂ rotatably supports the central shaft 21 with a cylindrical bearing 22 interposed in the central shaft 21, and a rotary body 23 is rotatably inserted in the cylindrical bearing 22. A wave washer 26 is interposed as a spring member between the rotating body 23 and the retaining ring 25 fitted in the ring groove 24 of the tubular bearing 22, and the rotating body 23 is biased toward the substrate 27. It is characterized by being formed.

Here, a boss portion 29 is formed so as to project at the end edge of the center hole 28 of the rotating body 23, and the boss portion 2 is formed on the seat surface 30a of the step portion 30 of the tubular bearing 22.
The protruding end of 9 is rotatably abutted. Therefore, the rotating body 23 axially biased by the wave washer 26 is positioned by bringing the boss portion 29 into contact with the step portion 30 of the tubular bearing 22,
The distance between the substrate 27 and the rotor 23, that is, the resistor circuit 31 and the contact
The contact pressure with 32 can always be kept constant.

In the figure, 33 is a flat washer, 34 is an L-shaped rod connecting the central shaft 21 and the rotating body 23, and an output pinion gear 35 is press-fitted into the tip of the central shaft 21. 36 is a resistance circuit of the substrate 27
It is a lead wire connected to 31.

[Effect of device]

As described above, according to the present invention, the rotating body contacts the central shaft or the stepped portion of the bearing by the bias of the spring member to keep the distance between the substrate and the substrate constant, so that the contact pressure between the resistance circuit and the contact is varied. In addition to being able to always make appropriate adjustments, the conventional troublesome contact pressure management becomes unnecessary, and the labor required for assembly can be reduced.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing an embodiment of the present invention, FIG. 2 is a vertical sectional view showing another embodiment of the present invention, FIG. 3 is a vertical sectional view showing a conventional example, and FIG. FIG. 3 is a view on arrow B of FIG. 3. A ₁ , A ₂ …… Assembled potentiometer, 2,21 …… Center axis,
3,31 ...... Resistance circuit, 4,27 ...... Substrate, 5,32 ...... Contact, 6,
23 …… Rotating body, 9,26 …… Wave washer (spring member), 22 …… Cylindrical bearing.

Claims (1)

[Scope of utility model registration request] 1. A potentiometer comprising a substrate on which an annular resistance circuit is formed, and a rotating body which is provided with a contactor for the resistance circuit projecting from the inner wall side and is rotatable so as to face the substrate. A central shaft or a cylindrical bearing that slidably supports the body in the rotational direction and the axial direction is fixed to the substrate side by penetrating the rotating body, and in the central portion of the central shaft or the bearing,
A step portion having an annular seating surface for the inner wall side of the rotating body is formed, and the rotating body is biased toward the substrate by a spring member supported by the central shaft or bearing on the outer wall side of the rotating body. An assembling type potentiometer, wherein an inner wall side is brought into contact with the seat surface.