JPH09273904A - Potentiometer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the invasion of dust from the exterior of a connector by providing a meshlike groove at the flat part of a connector terminal, and providing at least one step at the side, thereby eliminating an infinitesimal gap at the boundary of the terminal and a case. SOLUTION: A connector terminal 30 is electrically connected at its end to a resistor at the end of a board, and projected at the other end out of a case. The terminal 30 has a meshlike groove 31 on the surface and stepped parts 32 at the sides. A coiled spring is provided between the protrusion part of a brush mounting plate. The terminal 30 has the groove 31 molded integrally with the case on the flat surface and at least one stepped part 32 at the side. Thus, since no infinitesimal gap is generated at the boundary of te terminal 30 and the case, no dust is invaded from the exterior of the connector, and the output of the potentiometer is not varied.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a potentiometer used for a lift amount detecting portion of a valve for an exhaust gas circulation device of an automobile.

[0002]

2. Description of the Related Art A conventional potentiometer is disclosed in Japanese Unexamined Patent Publication No.
The one disclosed in Japanese Patent No. 215507 is known.

A conventional potentiometer will be described below with reference to the drawings. FIG. 6 is a sectional view of a conventional potentiometer, and FIG. 7 is a perspective view of a connector of the potentiometer, which is a main part of the conventional potentiometer.

In the figure, 1 is a shaft made of metal or resin. Reference numeral 2 is a case having a bearing 3 that fits with the shaft 1 at one end, the other end being open, and a groove 4 on the inner peripheral wall. Reference numeral 5 is a substrate made of resin or the like having a resistor (not shown) on the upper surface on the inner peripheral wall facing the groove 4.
Reference numeral 6 is a brush that slides on the resistor of the substrate 5. 7 is axis 1
The brush mounting plate is provided with a guide portion 8 that projects from the side toward the open side of the case 2 and that is in contact with the groove portion 4 of the inner peripheral wall of the case 2 on the side surface facing the brush 6. Reference numeral 9 denotes a connector terminal, one end of which is electrically connected to the resistor at the end of the substrate 5, and the other end of which is made of metal or the like having a smooth surface protruding to the outside of the case 2. Reference numeral 10 is a cover provided so as to cover the open side of the case 2. 11 is a brush mounting plate 7 and a cover 1
It is a coil spring made of metal or the like provided between the coil spring and the coil.

An assembling method of the potentiometer provided as described above will be described below.

First, after inserting the shaft 1 into the bearing portion provided in the case 2, the substrate 5, the brush mounting plate 7 and the coil spring 11 are inserted.
Insert Then, the cover 10 is placed on the opening of the case and covered to manufacture.

The operation of the potentiometer configured as described above will be described below.

The brush mounting plate 7 moves linearly along the groove 4 of the case 2 together with the shaft 1 fitted with the bearing 3 of the case 2.
When the shaft 1 was moved linearly, the brush 6 was displaced on the substrate 5 in proportion to the movement, and thus the output signal was taken out from the connector terminal 9 according to the counterpart device.

[0009]

However, in the above-mentioned conventional structure, the surface of the connector terminal 9 protruding from the case 2 to the outside is smooth, so that the boundary between the connector terminal 9 and the case 2 is minute. There is a problem in that a gap is generated and the air pressure inside the potentiometer is lowered by pulling the shaft 1 in the D direction, dust and the like enter from the outside of the connector terminal 1, and the output of the potentiometer fluctuates.

The present invention solves the above-mentioned conventional problems, and an object thereof is to provide a potentiometer having improved characteristics.

[0011]

In order to achieve the above object, the present invention provides a mesh-like groove on the surface of a connector terminal.

According to the present invention, it is possible to provide a potentiometer having improved reliability.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION The invention according to claim 1 of the present invention includes a shaft, a case having one end having a bearing fitted to the shaft, the other end being open, and having a groove portion on an inner peripheral wall, A substrate having a resistor on the upper surface provided on the inner peripheral wall of the case, a brush provided so as to be in sliding contact with the resistor of the substrate, and a protrusion protruding toward the inside from the insertion direction of the shaft. And a brush mounting plate having a guide portion that abuts a groove provided on the inner peripheral wall of the case on the side surface facing the brush, and one end of which is electrically connected to the resistor at the end of the substrate. The other end projects to the outside of the case and has a connector terminal having a mesh groove formed on the surface integrally molded with the case, a cover provided so as to cover the open side of the case, the brush mounting plate and the cover. And a coil spring between them.

The invention described in claim 2 is the same as claim 1
The connector terminal described above has a through hole in the center.

The invention according to claim 3 is the same as claim 1
The connector terminal described has at least one step on its side surface.

(First Embodiment) A potentiometer according to a first embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view of a potentiometer according to an embodiment of the present invention, and FIG. 2 is a perspective view of a connector terminal which is a main part thereof.

In the figure, 21 is a shaft made of metal or resin. 22 is a bearing 2 fitted at one end with the shaft 21
3 and the other end is open and the groove 24 is provided on the upper surface of the inner peripheral wall. Reference numeral 25 denotes a substrate made of resin or the like, which has a resistor (not shown) on the upper surface and is provided on the surface of the inner peripheral wall of the case 22 facing the groove portion 24. 26
Is a brush made of metal or the like that is in sliding contact with the resistor of the substrate 25. Reference numeral 27 denotes a brush attachment including a protrusion 28 protruding from the shaft 21 toward the opening side of the case 22 and a guide portion 29 that abuts a groove portion 24 provided in the inner peripheral wall of the case 22 facing the brush 26. It is a plate. 30 is the substrate 2 at one end
5 is electrically connected to the resistor at the end and the other end is the case 22.
Is a connector terminal made of metal or the like, which is formed integrally with the case 22 and has a mesh-shaped groove 31 on the surface and at least one step portion 32 on the side surface.
Reference numeral 33 is a cover made of resin or the like provided so as to cover the open side of the case 22. Reference numeral 34 is a coil spring made of metal or the like provided between the protrusion 28 of the brush mounting plate 27 and the cover 33. The connector terminal 30 has a mesh-shaped groove 31 in a flat surface portion integrally molded with the case 22, and at least one step portion 32 is provided on a side surface of the connector terminal 30 to form a boundary portion between the connector terminal 30 and the case 22. Since a minute gap is not formed in the connector, dust and the like do not enter from the B side of the connector portion 35, and the output of the potentiometer does not fluctuate.

With respect to the potentiometer according to the first embodiment of the present invention configured as described above, its assembling method will be described below.

First, the shaft 21 is inserted into the bearing 23 mounted in the case 22, and then the substrate 25, the brush mounting plate 27 and the coil spring 34 are inserted, and the cover 33 is placed in the opening of the case and the inside of the potentiometer is inserted. And is filled with the sealing resin 36.

The operation of the potentiometer according to the first embodiment of the present invention configured as described above will be described below.

The brush mounting plate 27 is in contact with the shaft 21 fitted into the bearing 23 of the case 22 and moves linearly along the guide portion 29 of the case 22. When this axis 21 is moved linearly,
The brush 26 displaces on the resistor in proportion to the movement, and thus the output signal corresponding to the counterpart device is taken out from the connector terminal 30.

(Second Embodiment) A potentiometer according to a second embodiment of the present invention will be described below with reference to the drawings.

FIG. 3 is a perspective view of a connector terminal which is a main part of the potentiometer according to the second embodiment of the present invention. Here, what is different from the first embodiment is only the shape of the connector terminal.

In FIG. 3, the connector terminal 41 is provided with a through hole 42 at the center of a plane molded integrally with the case 22, so that a minute gap is not formed at the boundary between the connector terminal 41 and the case 22. This has an effect that dust or the like does not enter from the outside of the connector terminal 41 and the output of the potentiometer does not change.

(Third Embodiment) A potentiometer according to a second embodiment of the present invention will be described below with reference to the drawings. Here, the difference from the first embodiment is that
Only the shape of the connector terminal.

FIG. 4 is a perspective view of a connector terminal which is a main part of the potentiometer according to the third embodiment of the present invention.

In FIG. 4, since the connector terminal 51 is provided with the mesh-shaped groove 52 on the plane formed integrally with the case 22, a minute gap is not formed at the boundary between the connector terminal 51 and the case 22. This has an effect that dust or the like does not enter from the outside of the connector terminal 51 and the output of the potentiometer does not change.

(Fourth Embodiment) A potentiometer according to a fourth embodiment of the present invention will be described below with reference to the drawings. Here, the difference from the first embodiment is that
Only the shape of the connector terminal.

FIG. 5 is a perspective view of a connector terminal which is a main part of the potentiometer according to the fourth embodiment of the present invention.

In FIG. 5, the connector terminal 61 is provided with at least one step portion 62 on the side surface integrally molded with the case 22, so that the connector terminal 61 and the case 2 are formed.
Since a minute gap is not formed at the boundary with the connector 2, dust and the like will not enter from the outside of the connector terminal 61 and the output of the potentiometer will not fluctuate.

[0032]

As described above, according to the present invention, since a minute gap is not formed at the boundary between the connector terminal and the case, dust and the like do not enter from the outside of the connector, so that the output of the potentiometer does not fluctuate and reliability is improved. It is possible to provide an improved potentiometer.

[Brief description of drawings]

FIG. 1 is a sectional view of a potentiometer according to a first embodiment of the present invention.

FIG. 2 is a perspective view of a connector terminal of a potentiometer, which is a main part of the same.

FIG. 3 is a perspective view of a connector terminal of a potentiometer, which is a main part in the second embodiment of the present invention.

FIG. 4 is a perspective view of a connector terminal of a potentiometer, which is a main part in a third embodiment of the present invention.

FIG. 5 is a perspective view of a connector terminal of a potentiometer, which is a main part in a fourth embodiment of the present invention.

FIG. 6 is a sectional view of a conventional potentiometer.

FIG. 7 is a perspective view of a connector terminal of a conventional potentiometer.

[Explanation of symbols]

 21 Shaft 22 Case 23 Bearing 25 Substrate 26 Brush 27 Brush Attachment Plate 28 Projection 29 Guide 30 Connector Terminal 31 Mesh-like Groove 32 Step 33 Cover 34 Coil Spring 41 Connector Terminal

Claims (3)

[Claims] 1. A shaft, a case having one end having a bearing fitted to the shaft, the other end being open, and a groove portion on an inner peripheral wall, and a resistor provided on an upper surface provided on the inner peripheral wall of the case. A board having a board, a brush provided so as to be in sliding contact with the resistor of the board, and a protrusion projecting toward the open side from the insertion direction of the shaft toward the inside, and the side surface of the case facing the brush. A brush mounting plate having a guide portion that abuts a groove provided on the inner peripheral wall, one end of which is electrically connected to the resistor at the end of the substrate, and the other end of which is projected to the outside of the case and integrated with the case. A potentiometer provided with a connector terminal having a mesh-shaped groove on a molded surface, a cover provided so as to cover the open side of the case, and a coil spring between the brush mounting plate and the cover. 2. The potentiometer according to claim 1, wherein a through hole is provided in the center of the connector terminal. 3. The potentiometer according to claim 1, wherein at least one step portion is provided on the side surface of the connector terminal.