JPH09171902A - Position sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To decrease assembling manhours and to reduce the cost of a product furthermore by directly exposing the outer surface of an element member to the outside. SOLUTION: An outer surface 47 of an element member 20 is exposed to the outside. The heat generated in the element member 20 is directly radiated from the outer surface 47, and the heat radiation property is enhanced. Furthermore, in the element member 20, an element member part 42, wherein a recess part 40 accepting a shaft part 24 of a rotor 16 is the center, and a terminal part 44 form a unitary body. Thus, the dimensional distortion of the element member 20 caused by thermal expansion can be made minimum, and expensive ceramics inferior in formability is omitted. Thus, the number of parts and the assembling manhours are decreased, measuring accuracy is improved and the reliability in electric connection between a resistor element and the terminal part is improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a position sensor for detecting a rotation angle of a measured object.

[0002]

2. Description of the Related Art For example, a position sensor such as a potentiometer is widely used to detect the rotation angle of a throttle valve of an automobile. FIG. 3 is a cross-sectional view showing a conventional position sensor 100 (actual open flat 4-92).
601). The position sensor 100 mainly includes a main body housing 102 and the main body housing 102.
A rotor 104 rotatably supported on the rotor 10;
4, a sliding brush 106 fixed to one end, a resistance element 108 electrically contacting the sliding brush 106 is formed on the surface, and a substrate-shaped element member 110 fixed to the main body housing 102, and this element member 1
10 includes a terminal 114 extending to the outside of the main body housing 102 via the conductor 112, and a cover housing 116 for sealing the element member 110 and the like. Incidentally, the rotor 10
Reference numeral 4 includes a lever 118 connected to a throttle valve (not shown) and the like, and is biased by a torsion coil spring 120 so as to return to its original position. Further, the boundary between the main body housing 102 and the cover housing 116 is sealed with an adhesive 124.

[0003]

Since the conventional position sensor 100 is composed of a large number of parts, it is not only complicated in management of parts, but also the number of assembly steps, material cost, etc. are increased, so that cost reduction is not possible. It was difficult.

Further, since the air layer 122 between the element member 110 and the cover housing 116 exists outside the element member 110, the element member 110 is
The heat generated in the element is not sufficiently dissipated, and the element member 110
There is a possibility that an error may occur in the resistance value indicated by the position sensor 100 due to the thermal expansion of. The element member 11
If 0 is made of ceramic, the heat dissipation is improved, but it is expensive and inferior in moldability.

Further, the element member 110 and the terminal 1
Since the conductors 112 are interposed between the fourteen, there are a plurality of connection points by rivets 126, solders 128, etc. for interconnecting them. Therefore, there is a problem that the reliability of electrical connection is poor.

Therefore, it is a first object of the present invention to provide a position sensor which can reduce the number of assembling steps and thus the product cost by reducing the number of parts.

A second object of the present invention is to provide a position sensor with improved electrical reliability by greatly reducing the number of electrical connection points.

[0008]

A position sensor according to claim 1, wherein a housing, a rotor integrally having a shaft receiving portion, a rotor for fixing the brush member and rotatably supported by the housing, and the brush member. In a position sensor having a resistance element formed on a surface thereof, the resistance element being in contact with the outer surface of the element member is directly exposed to the outside.

According to a second aspect of the present invention, in a position sensor, a rotor is integrally provided with a housing, a shaft receiving portion, a brush member is fixed, and the rotor is rotatably supported by the housing. In a position sensor comprising an element member having an element formed on the surface thereof, and a terminal portion connected to the resistance element through an electrical connection means, the terminal portion fitting with a mating contact, the element member and the terminal portion are It is characterized by being integrally formed.

Further, the position sensor of claim 3 is
A rotor integrally fixed to the housing and having a shaft receiving portion and fixing the brush member and rotatably supported by the housing; and an element member having a resistance element formed on the surface for slidingly contacting the brush member, In a position sensor, comprising a terminal portion that mates with a mating contact, connected to the resistance element via an electrical connection means, wherein the electrical connection means and the terminal portion are formed on a base surface of the element member. It is characterized in that it is a formed conductor pattern.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the position sensor of the present invention will be described below with reference to the accompanying drawings.
FIG. 1 is a vertical sectional view showing an embodiment of the position sensor of the present invention. FIG. 2 shows an element member used in the position sensor of FIG. 1, and is an (A) plan view, (B) center sectional view, and (C) bottom view, respectively.

The position sensor 1 includes a rotor receiving recess 1
Housing 1 integrally including 2 and connector portion 14
0, the rotor 16 received in the rotor receiving recess 12, the wiper (brush member) 18 fixed to the rotor 16,
And an element member 20 that contacts the wiper 18. The rotor 16 has a shaft receiving portion 22 that receives a shaft (not shown) such as a throttle valve of an automobile, and a shaft portion 24 that is axially supported by a recess 40 of the element member 20 on the opposite side of the shaft receiving portion 22. . A flat surface portion 26 is formed at a position close to the shaft portion 24 to which the wiper 18 is fixed by a known method such as heat staking. A torsion coil spring 28, a spring washer 30, and a sealing material such as an O-ring 32 are interposed between the housing 10 and the rotor 16.
The seal material may be an X ring, U packing, V packing, or the like. The torsion coil spring 28 is for urging the rotor 16 around its axis 34 to an initial position. The spring washer 30 is for preventing the play between the housing 10 and the rotor 16 in the vertical direction in FIG. Further, the O-ring 32 is attached to the housing 1
0 and the rotor 16 are kept airtight to prevent water, oil, etc. from entering the housing 10 from below in FIG. The wiper 18 is formed of an elastic metal plate, and the brush portions 36 and 37 slidably contacting the element member 20 and the projection 27 on the flat surface portion 26 are heat caulked to the flat surface portion 26 of the rotor 16. And a fixed portion 38 to be fixed.

In FIGS. 1 and 2, the element member 2
In No. 0, the element portion 42 centering on the concave portion 40 that receives the shaft portion 24 of the rotor 16 and the terminal portion 44 are integrated. The material of the base 46 of the element member 20 is preferably liquid crystal polymer in consideration of heat resistance and moldability that can withstand the firing temperature described later, but other materials such as PPS may be used. Since the outer surface 47 of the element member 20 is exposed to the outside without providing a cover housing like the conventional position sensor, the heat generated in the element member 20 is dissipated directly from the outer surface 47, and the heat dissipation is excellent. . Therefore, the dimensional strain of the element member 20 due to the thermal expansion is minimized, and the expensive and inferior moldability of the ceramic is eliminated. A first conductor pattern 48, which is formed concentrically with the recess 40 and extends toward the tip of the terminal portion 44, is formed on the bottom surface 45 of the element portion 42. Further, the first conductor pattern 48 is formed in an arc shape outside the first conductor pattern 48 and extends toward the tip of the terminal portion 44.
Second and third conductor patterns 50 and 52 are formed to extend in parallel with. Further, a part (an angular range of about 10 °) of the second and third conductor patterns 50 and 52 is overlapped with each other on the outside of the first conductor pattern 48 and in a circular arc shape.
The resistive element 54 formed by 4, 76 is formed. The first brush portion 36 of the wiper contacts the resistance element 54, and the second brush portion 37 contacts the circular first conductor pattern 48. For this reason, the path length of the resistance element 54 changes according to the rotation angle of the rotor 16, so that the resistance value of the rotor 16 of the rotor 16 is determined from the resistance value between the first conductor pattern 48 and the second conductor pattern 50 (or the third conductor pattern 52). The rotation angle can be detected. The first to third conductor patterns 48, 5
0 and 52 extend from the bottom surface 45 of the terminal portion 44 to the upper surface 58 via the tip side surface 56. By forming the conductor patterns 48, 50, and 52 on both surfaces of the terminal portion 44, the number of contact points between the terminal portion 44 and the mating female contact (not shown) to be fitted is increased, and the contact reliability is improved. Also, the terminal portion 4
4 is a base 4 in which the conductor patterns 48, 50 and 52 are the same.
Since it is formed on the terminal 6, the terminal irregularity that tends to occur in the case of a metal terminal does not occur.

Next, the manufacturing process of the element member 20 will be described. First, the base 46 is molded with a resin such as a liquid crystal polymer that can be plated. Next, MID (Molded
The bottom surface 45 of the base 46, the tip side surface 56,
A copper plating layer is three-dimensionally formed on the upper surface 58 in the shape of the conductor patterns 48, 50 and 52. The MID technique includes a one-shot molding method and a two-shot molding method, and either one may be used, but the one-shot molding method will be described below as an example.

First, the surface of the base 46 is subjected to etching treatment with an aqueous solution of potassium hydroxide or the like to roughen the surface, followed by catalytic treatment, and electroless copper plating is applied to the entire surface. afterwards,
Further, a resist is uniformly applied to the entire surface by an electrodeposition resist method, a spray method, a dip method or the like. In the subsequent exposure step, the number of exposures is divided into two or three, simultaneous exposure is performed using a plurality of light sources, or exposure is performed using a reflector. Next, the resist except for the conductor patterns 48, 50 and 52 is removed, and then the copper layer plated with electroless copper is removed with an acid or the like. Furthermore, the conductor patterns 48, 5
By removing the resist on 0 and 52, three-dimensional conductor patterns 48, 50 and 52 are formed.

Subsequently, a nickel plating layer is formed on the formed copper plating layer, and a gold plating layer is formed thereon as required. Conductor pattern 4 by nickel plating
Oxidation of 8, 50, 52 due to heat is suppressed, and gold plating improves connection reliability with the mating female contact (not shown) and the resistance element 54. Next, a paste mainly composed of carbon powder, which becomes the resistance element 54 when fired, is printed on the bottom surface 45 of the base 46, and the printed base 46 is fired at about 250 ° C., whereby the element member 20 is completed.

Next, the assembly process of the position sensor 1 will be described. First, the torsion coil spring 28 and the spring washer 30 are arranged in the rotor receiving recessed portion 12 of the housing 10, and the rotor 16 having the wiper 18 and the O-ring 32 mounted thereon is mounted thereon. Then, the rotor 16
A flat washer 60 is arranged around the shaft 24 of the. next,
The element member 20 is provided in the hole 62 penetrating the connector portion 14.
The terminal portion 44 of the rotor 16 and the shaft portion 24 of the rotor 16 are inserted.
Is fitted into the recess 40 of the element member 20. At this time, the convex portion 64 facing the hole 62 and the groove 66 formed in the upper surface 58 of the terminal portion 44 are engaged with each other to prevent the element member 20 from advancing (moving to the right in FIG. 1). Next, the outer periphery 68 of the housing 10 is heat-crimped along the arc-shaped outer periphery of the element portion 42, whereby the element member 2
0 is temporarily fixed to the housing 10. Finally, the adhesive 70 is applied between the outside of the element portion 42 and the housing 10 so that the element portion 42 and the housing 1
The sealing property between 0 is secured. The sealing property between the terminal portion 44 and the housing 10 can be achieved by a sealing means between the inner wall 72 of the connector portion 14 and a mating connector (not shown).

The element member 20 is equivalent to a conventional element member and terminal integrated with each other, and there is virtually no connection point between them, so that the number of parts and the number of assembling steps are reduced. Not only that, the electrical connection reliability is greatly improved.

Although the preferred embodiment of the position sensor of the present invention has been described above, it is needless to say that the present invention is not limited to the above-described embodiment, and various modifications and changes can be made as necessary.

[0020]

According to the position sensor of the first aspect, since the outer surface of the element member is exposed to the outside,
Not only the number of parts and the number of assembling steps can be reduced, but also the heat dissipation of the element member is improved and the measurement accuracy is improved.

Further, according to the position sensor of the second and third aspects, not only the number of parts and the number of assembling steps can be reduced, but also the reliability of the electrical connection between the resistance element and the terminal portion is improved. Play.

[Brief description of the drawings]

FIG. 1 is a vertical cross-sectional view showing an embodiment of a position sensor of the present invention.

2A and 2B show an element member used in the position sensor of FIG. 1, and are an (A) plan view, a (B) central cross-sectional view, and a (C) bottom view, respectively.

FIG. 3 is a vertical cross-sectional view showing a conventional position sensor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Position sensor 10 Housing 16 Rotor 18 Brush member (wiper) 20 Element member 22 Shaft receiving part 44 Terminal part 46 Base 47 Outer surface 48, 50, 52 Conductor pattern 54 Resistance element

Claims (3)

[Claims] 1. An element having a housing, a shaft receiving portion integrally formed thereon, a rotor for fixing a brush member and rotatably supported by the housing, and a resistance element formed on the surface for contacting the brush member. A position sensor comprising a member, wherein the outer surface of the element member is directly exposed to the outside. 2. An element having a housing, a shaft receiving portion, a rotor for fixing a brush member and being rotatably supported by the housing, and a resistance element formed on the surface for contacting the brush member. Members,
A position sensor connected to the resistance element via an electrical connection means, the position sensor having a terminal portion fitted with a mating contact, wherein the element member and the terminal portion are integrally formed. Position sensor. 3. An element having a housing, a shaft receiving portion integrally formed thereon, a rotor for fixing a brush member and being rotatably supported by the housing, and a resistance element formed on the surface for contacting the brush member. Members,
A position sensor, comprising a terminal portion that mates with a mating contact, connected to the resistance element via an electrical connection means, wherein the electrical connection means and the terminal portion are formed on a base surface of the element member. Position sensor, which is a formed conductor pattern.