JP2002057007A - Potentiometer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a potentiometer provided with a plurality of systems of circuit patterns which are formed without increasing the sizes of an attaching space and a resistance board. SOLUTION: On the lower surface 21 of the resistance board 2, a main circuit pattern constituting a potentiometer circuit which detects the stepping-on measurement of an accelerator pedal is formed. In addition, on the upper surface 22 of the board 2, a sub-circuit pattern constituting a switch circuit for detecting idling position is formed. A brush 53 for main circuit and another brush 63 for sub-circuit both of which are respectively fixed to paired brush bases 5 and 6 facing both surfaces 21 and 22 of the board 2 are respectively brought into contact with the main and sub-circuit patterns.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a potentiometer used as, for example, an accelerator sensor or a vehicle height sensor in an automobile.

[0002]

2. Description of the Related Art Conventionally, a potentiometer used as, for example, an accelerator sensor of an automobile is provided inside a body.
A resistance substrate, a resistance track formed on the surface of the resistance substrate, a shaft concentrically arranged with the resistance substrate and rotatably inserted through the body, and fixed to a brush mount attached to the shaft A brush whose tip is in contact with the surface of the resistance track. That is, when the shaft is rotated by depressing the accelerator pedal, the contact position of the brush with respect to the resistance track moves in the circumferential direction, the electric resistance value changes, and a detection voltage corresponding to the amount of depression of the accelerator pedal is output. Things.

When the potentiometer is provided with, for example, a switch for detecting an idling position, such a switch or the like is externally provided outside the body, or disposed on a surface of the resistance substrate on which resistance tracks are formed.

[0004]

However, according to the prior art potentiometer described above, when the switch for detecting the idling position is externally mounted, an external mounting space is required outside the body, and the structure is not sufficient. There is also a problem that is complicated.

[0005] In addition, a resistance track provided on a resistance substrate usually requires two systems of outputs in order to achieve fail-safe. That is, since two types of resistance patterns are provided on the surface of the resistance substrate in an arc shape symmetric with respect to the axis, the mounting density of the circuit patterns is high. Therefore, in order to provide the switch circuit pattern for detecting the idling position on this surface, it is necessary to expand the area of the resistor substrate in the radial direction, and there is a problem that the size is increased.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and has as its technical object the provision of a plurality of circuit patterns without increasing the mounting space or the size of the resistor substrate. To provide a potentiometer.

[0007]

Means for Solving the Problems The technical problems described above are:
This can be effectively solved by the present invention. That is, a potentiometer according to the present invention includes a resistor substrate having a main circuit pattern extending on one surface in a circumferential direction around an axis and a sub circuit pattern formed on the other surface; A shaft concentrically disposed and rotatably supported by bearings; a pair of brush mounts disposed on and attached to the shaft so as to face both surfaces of the resistance substrate; and one surface of the resistance substrate A main circuit brush made of a conductive metal fixed to a brush base opposite to the main circuit pattern and having a tip contacted with the main circuit pattern, and a tip fixed to the brush base opposed to the other surface of the resistance substrate and having a tip corresponding to the sub circuit pattern. And a sub-circuit brush made of a conductive metal contacted.

In the above configuration, more preferably, a plurality of main circuit patterns are provided in the circumferential direction, and each input terminal and each ground terminal connected to both ends thereof are grouped with each other and arranged on the resistance substrate. The sub-circuit pattern forms a switch circuit pattern.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a potentiometer according to the present invention will be described in detail with reference to the preferred embodiments shown in the drawings. First, FIG. 1 is a cross-sectional view of the potentiometer cut along a plane passing through its axis. Reference numeral 1 in FIG. 1 denotes a body of the potentiometer.

The body 1 is entirely formed of synthetic resin, and extends axially from the inner periphery of the outer shell 11 and the bottom wall 11a of the outer shell 11 to the inner space of the outer shell 11. A cylindrical bearing holding portion 12, an annular sealing material holding portion 13 extending concentrically with the bearing holding portion 12 from the bottom wall 11a to the outside of the outer shell portion 11, A spring holding portion 14 having an annular groove formed on the bottom wall 11 a and located on an outer peripheral side; a terminal holding portion 15 formed on a part of the outer shell 11 in a circumferential direction; It comprises a lid plate 16 sealed at the upper end and a connector housing 17 attached to the terminal holding portion 15.

A resistance board 2 made of a material having excellent electrical insulation such as glass epoxy resin or ceramics is fixed to the inner periphery of the outer shell 11 of the body 1 at the height of the upper surface of the terminal holder 15. Have been. The resistance substrate 2 includes a cylindrical lower space S1 and an upper space S2 formed inside the outer shell portion 11.
It is arranged to partition into.

FIG. 2 is a bottom view of the resistance substrate 2, and FIG. 3 is a top view of the same. That is, the resistance substrate 2 is formed with the shaft hole 2a.
A track forming portion 2b having an outer peripheral edge formed in an arc shape concentric with the shaft hole portion;
And a terminal arrangement portion 2c which is superposed on the upper surface of the terminal holding portion 15 in FIG.

As shown in FIG. 2, a main circuit pattern 100 is provided on the lower surface 21 of the resistance substrate 2. The main circuit pattern 100 constitutes a two-system detection circuit pattern as a potentiometer. The first conductor track 101 and the second conductor track 101 extend in an arc concentric with the shaft hole 2a and are formed symmetrically with respect to each other. Conductor tracks 102 and a first resistance track 103 and a second resistance track 104 symmetrical to each other and formed on the outer peripheral side of the conductor tracks 101 and 102 in concentric arcs, respectively. The first and second conductor tracks 101 and 102 are made of a material obtained by adding a thermosetting resin paste to a conductor metal powder such as silver, and the first and second resistance tracks 103 and 104 are made of carbon or the like. Made of a material obtained by adding a thermosetting resin paste to the above-mentioned resistance material powder, and formed into an appropriate film thickness by a method such as printing.

One end of the first resistance track 103 is led out to the terminal arrangement portion 2c of the resistance substrate 2 via the wiring pattern 103a, and the terminal arrangement portion 2c is formed.
c is connected to a first Vcc input terminal 105 provided so as to penetrate in the thickness direction. The other end is connected to the connection conductor 1
A first ground (GND) which is led out to the terminal arrangement portion 2c of the resistor substrate 2 via the wiring pattern 103b provided symmetrically to the terminal arrangement portion 03a and penetrates the terminal arrangement portion 2c in the thickness direction. ) Terminal 106.

One end of the second resistance track 104 is led out to the terminal arrangement portion 2c via the wiring pattern 104a, and the second resistance track 104 is provided through the terminal arrangement portion 2c in the thickness direction. It is connected to the Vcc input terminal 107. Further, the other end is led out to the terminal arrangement portion 2c via the wiring pattern 104b, and is connected to a connection terminal 108 provided through the terminal arrangement portion 2c in the thickness direction. Upper surface 22 of resistance substrate 2 shown in FIG.
Is connected to a second ground (GND) terminal 109 provided through the terminal arrangement portion 2c in the thickness direction through a wiring pattern 104c formed in the second wiring pattern.

First and second conductor tracks 101, 10
2 has one end in the circumferential direction connected to first and second connection terminals 110 and 111 provided through the track forming portion 2b of the resistance substrate 2 in the thickness direction, respectively. From 111, the resistance substrate 2 shown in FIG.
Patterns 101a, 102 formed on the upper surface 22 of
Through the terminal a, it is led to the terminal arrangement part 2c, and is connected to the first and second potentiometer output terminals 112 and 113 provided through the terminal arrangement part 2c in the thickness direction.

As shown in FIG. 3, on the upper surface 22 of the resistance substrate 2, the above-described wiring patterns 104c, 101a,
In addition to 102a, a sub-circuit pattern 200 is provided. The sub-circuit pattern 200 constitutes a switch circuit for detecting an idling position. The third conductor track 201 extends in an arc concentric with the shaft hole 2a, and the arc-shaped switch track 202 located on the outer peripheral side thereof. And The third conductor track 201 and the switch track 202 are provided with the first and second conductor tracks 10.
Made of the same material as 1,102, switch track 2
02 has an insulating portion 202a formed at a predetermined position in the extension direction.

One end of the third conductor track 201 is led out to the terminal arrangement portion 2c of the resistance substrate 2 via the wiring pattern 201a, and the third conductor track 201 is connected to the terminal arrangement portion 2c.
switch input terminal 2 which is provided so as to penetrate c in the thickness direction.
03 is connected. Also, the switch track 202
Means that the end of the third conductor track 201 on the opposite side to the lead-out end is led out to the terminal placement portion 2c of the resistance substrate 2 via the wiring pattern 202b, and the terminal placement portion 2c is placed in the thickness direction. Is connected to a switch output terminal 204 provided through the terminal.

As shown in FIGS. 2 and 3, the first and second Vccs connected to the main circuit pattern 100 are connected.
The input terminals 105 and 107, the first and second ground terminals 106 and 109, the first and second potentiometer output terminals 112 and 113, and the switch input terminal 203 and the switch output connected to the sub-circuit pattern 200 side. The terminals 204 are all arranged in the terminal arrangement section 2c. Further, the first Vcc input terminal 105 and the second Vcc
The input terminals 107 are adjacent to each other and the first ground terminal 1
06 and the second ground terminal 109 are adjacent to each other, and the first potentiometer output terminal 112 and the second potentiometer output terminal 113 are adjacent to each other and provided in a grouped state.

The above-mentioned Vcc input terminals 105, 10
7, the ground terminals 106 and 109, the potentiometer output terminals 112 and 113, the switch input terminal 203 and the switch output terminal 204 are connected to corresponding connector pins (not shown) arranged on the inner periphery of the connector housing 18. I have.

Returning to FIG. 1, a cylindrical bearing 3 is mounted on the inner periphery of a bearing holding portion 12 formed in the body 1, and a shaft 4 is mounted on the inner periphery of the bearing 3. It is inserted rotatably. An outer end of the shaft 4 extending to the outside of the body 1 is connected to an accelerator (not shown) via a lever 41. The bearing 3 has one end in the axial direction in contact with the end surface of the bearing holding portion 12 and the other end in contact with the annular step portion 4 a formed on the outer peripheral surface of the shaft 4, thereby preventing the shaft 4 from rattling in the axial direction. Along with
The concentricity with the above-described resistance substrate 2 is maintained.

A seal ring 18 made of an elastic material such as rubber is mounted on the inner periphery of the seal material holding portion 13 of the body 1. The inner peripheral surface of the seal ring 18 is in close contact with the outer peripheral surface of the shaft 4 so as to be slidable, thereby preventing foreign matter from entering the body 1 from the outside.

A pair of brush stands 5 and 6 are mounted on the outer periphery of the shaft 4 reaching the upper space S2 in the outer shell 11 of the body 1 from the inner periphery of the shaft hole 2a of the resistance substrate 2. The brush bases 5 and 6 are made of insulating synthetic resin material such as polyacetal. Of these, the lower brush base 5 faces the lower surface 21 of the resistance substrate 2 and the upper brush base 6 Is located in the upper space S2,
It faces the upper surface 22 of the resistance substrate 2.

FIG. 4 is a top view showing the lower brush base 5, and FIG.
Is a bottom view showing the upper brush stand 6. As shown in FIG. 4, the lower brush base 5 includes a boss portion 51 and a pair of rotary wing portions 52, 52 extending from one axial end of the boss portion 51 to a 180 ° symmetrical position toward the outer periphery in a point-symmetrical shape. And The upper brush base 6 is formed in a symmetrical shape with the lower brush base 5, that is, the boss 61 and a point symmetrical shape from one axial end of the boss 61 to a 180 ° symmetrical position toward the outer peripheral side. And a pair of rotating wing portions 62, 62 extending in the direction.

The lower brush base 5 and the upper brush base 6
May have the same shape.

The brush bases 5 and 6 are provided with bosses 51 and 6
In a state where the members 1 abut against each other, they are externally inserted into the upper portion of the shaft 4, and are fixed to the upper end portion of the shaft 4 in a state where they are prevented from falling off via a retaining ring 42. The retaining ring 42
Are accommodated in a counterbore portion formed at the upper end opening of the shaft hole 61a in the upper brush base 6, thereby shortening the shaft 4 in the axial direction and, consequently, reducing the axial dimension of the body 1. It is planned.

Rotating blades 52 of the lower brush base 5;
The rotor blades 62, 62 of the upper brush base 6 are maintained at a predetermined distance from the resistance substrate 2 by the bosses 51, 61 which abut against each other. Further, the upper portion of the shaft 4 and the boss portions 51,
The inner circumferences (axial holes) 51a, 61a of the 61 are formed in non-circular cross-sectional shapes corresponding to each other. Therefore, each of the brush stands 5, 6 is prevented from rotating with respect to the shaft 4, that is, the shaft 4 It is designed to be rotated integrally with it.

A spring receiver 7 is externally inserted into the shaft 4 in a state of contacting the lower surface of the lower brush base 5. A coil spring 8 is interposed between the spring receiver 7 and the spring holding portion 14 of the body 1 in an appropriate compressed state. That is, the urging force of the coil spring 8 acts to press the lower brush base 5 (boss 51) against the upper brush base 6 (boss 61) fixed by the retaining ring 42 via the spring receiver 7. I do.

Rotary wings 52, 5 in lower brush base 5
The upper surface of 2 is opposed to the lower surface 21 of resistance substrate 2, and a pair of main circuit brushes 53, 54 formed of a conductive metal plate are attached to this surface. Each of the main circuit brushes 53 and 54 is formed with a pair of leaf spring-like sliding pieces 531, 532, 541 and 542, respectively. The first conductor track 101 and the second conductor track 102 in the main circuit pattern 100 on the lower surface 21 of the second
The outer peripheral sliding pieces 532 and 542 respectively contact the first resistance track 103 and the second resistance track 104 in the main circuit pattern 100 at positions aligned on a straight line orthogonal to the axis. ing.

The rotating blades 62, 6 of the upper brush stand 6
A lower surface of the rotating substrate 2 is opposed to an upper surface 22 of the resistance substrate 2, and a sub-circuit brush 63 formed of a conductive metal plate is attached to a lower surface of one of the rotating blades 62.
The sub-circuit brush 63 includes a pair of leaf spring-like sliding pieces 6.
31 and 632 are formed, and a sliding piece 631 on the inner peripheral side is formed.
Are located on the third conductor track 201 in the sub-circuit pattern 200 on the upper surface 22 of the resistance substrate 2, and the sliding piece 632 on the outer peripheral side is located on the switch track 202 in the sub-circuit pattern 200 on a straight line perpendicular to the axis. They are in contact at the top line. The sliding pieces 631, 63
2 contacts the third conductor track 201 and the switch track 202 on the same phase as the sliding pieces 531 and 532 of the one main circuit brush 53 attached to the lower brush base 5.

When the shaft 4 is rotated in conjunction with the depression of an accelerator pedal (not shown), the upper and lower brush mounts 5 and 6 fixed to the shaft 4 Rotate around. Therefore, the sliding pieces 531, 5 of the main circuit brushes 53, 54 attached to the lower brush base 5
32, 541, 542 and the contact positions of the sliding pieces 631, 632 of the sub-circuit brush 63 attached to the upper brush base 6 continuously change in the circumferential direction.

Therefore, in the main circuit pattern 100 constituting the detection circuit as the potentiometer, the first and second Vcc input terminals 105 and 107
By applying an input voltage between the first and second ground terminals 106 and 109, the resistance of the main circuit brushes 53 and 54 with respect to the first resistance track 103 and the second resistance track 104 is determined. Since the value changes, an output corresponding to the depression amount of the accelerator pedal is obtained from the first potentiometer output terminal 112 and the second potentiometer output terminal 113. The outputs from the first potentiometer output terminal 112 and the second potentiometer output terminal 113 are almost the same, thereby achieving fail-safe.

On the other hand, in the sub-circuit pattern 200 constituting the switch for detecting the idling position, the contact position of the sliding piece 632 of the sub-circuit brush 63 with respect to the switch track 202 is on the insulating portion 202a of the switch track 202. Only at this time, the output of the switch output terminal 204 is turned off, whereby the idling position when the accelerator pedal is depressed is detected.

In the configuration according to the above-described embodiment, the main circuit pattern 100 as a two-system potentiometer circuit for fail-safe is formed on the lower surface 21 of the resistance substrate 2 and the sub-circuit as the idling position detection switch is formed. The pattern 200 is connected to the resistance substrate 2
Is formed on the upper surface 22. For this reason, there is no need for an installation space as in the case where an idling position detection switch circuit is externally provided outside the body 1, and a potentiometer circuit and an idling position detection switch circuit are provided on one surface of the resistor substrate 2. It is not necessary to increase the mounting density or expand the area of the resistor substrate 2 in the radial direction as in the case of the arrangement.

In this type of potentiometer, the output is divided into two systems by a first potentiometer output terminal 112 and a second potentiometer output terminal 113.
The cc input terminal and the ground terminal may have specifications common to both systems for the purpose of reducing the number of parts and the number of steps. According to this embodiment, as shown in FIGS. 2 and 3, the first Vcc input terminal 105 and the second Vcc input terminal 107 are adjacent to each other and the first ground terminal 10
6 and the second ground terminal 109 are provided adjacent to each other and are grouped, so that it is possible to easily cope with the case where the common specification is used. Also, the Vcc input terminal 10
5, 107, and the first and second ground terminals 106, 1
09 are grouped,
Reliability is also improved.

In this type of potentiometer, two resistive substrates are arranged, a main circuit pattern 100 is formed on one of the opposing surfaces of the two resistive substrates, and a sub circuit pattern 200 is formed on the other. It is also conceivable to arrange a single brush base with brushes on both sides,
In this case, due to the difference between the mounting positions of the two resistance substrates, etc.
Since both resistance substrates cannot be formed in the same shape, the number of steps is increased, and only the main circuit pattern 100 and the sub circuit pattern 2
00 and misalignment with each brush is likely to occur. On the other hand, according to the illustrated embodiment, since the resistance substrate 2 is single, there is no problem as described above.

In the illustrated embodiment, the sub-circuit pattern 200 is a single system idling position detection switch.
It can be changed according to the purpose and conditions, such as a system idling position detection switch, one system potentiometer circuit and one system idling position detection switch, or one system or two systems of potentiometer circuits.

[0038]

According to the potentiometer according to the first aspect of the present invention, the main circuit pattern is arranged on one surface of the resistor substrate, and the sub circuit pattern such as the switch circuit for detecting the idling position is arranged on the other surface. The size can be reduced as compared with the case where each pattern is arranged on one side or externally attached to the body.

According to the potentiometer of the second aspect of the present invention, each input terminal and each ground terminal are grouped with each other and arranged on the resistor substrate.
The reliability can be improved by reducing the possibility of a short circuit between the input terminal and the ground terminal, and it is easy to cope with the case where the input terminal and the ground terminal are shared.

According to the potentiometer according to the third aspect of the present invention, by configuring the sub-circuit pattern as a switch circuit pattern, it is possible to provide a small-sized potentiometer with a switch without requiring an external switch mechanism.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a preferred embodiment of a potentiometer according to the present invention by cutting along a plane passing through an axis thereof.

FIG. 2 is a bottom view of the resistance substrate according to the embodiment.

FIG. 3 is a top view of the resistance substrate according to the embodiment.

FIG. 4 is a top view of a lower brush base to which a main circuit brush is attached in the embodiment.

FIG. 5 is a bottom view of the upper brush stand to which the sub-circuit brush is attached in the embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Body 2 Resistance board 21 Lower surface (one surface) 22 Upper surface (other surface) 3 Bearing 4 Shaft 5 Lower brush stand 53, 54 Brush for main circuit 6 Upper brush stand 63 Brush for sub circuit 7 Spring receiver 8 Coil spring 100 Main circuit pattern 101 First conductor track 102 Second conductor track 103 First resistance track 104 Second resistance track 105 First Vcc input terminal 106 First ground terminal 107 Second Vcc input terminal 109 Second Ground terminal 112 first potentiometer output terminal 113 second potentiometer output terminal 200 sub-circuit pattern 201 third conductor track 202 switch track 202a insulating part

Claims (3)

[Claims] 1. A main circuit pattern (100) extending in a circumferential direction around an axis is formed on one surface (21), and a sub-circuit pattern (200) is formed on the other surface (22). A resistor substrate (2), a shaft (4) concentrically arranged with the main circuit pattern (100) and rotatably supported by a bearing (5); and both surfaces (21) of the resistor substrate (2). , 22) and a pair of brush stands (5, 6) attached to the shaft (4) and facing the first surface (21) of the resistance substrate (2). ), A main circuit brush (53, 54) made of a conductive metal, the tip of which is in contact with the main circuit pattern (100), and a brush stand facing the other surface (22) of the resistance substrate (2). (6) Constant differential Re tip potentiometer, characterized in that it comprises a brush (63) for sub-circuit consisting of the sub-circuit pattern (200) to the contacted conductive metal. 2. A plurality of main circuit patterns (100) are provided, and input terminals (10) connected to both ends thereof are provided.
5. The potentiometer according to claim 1, wherein the at least one of the first and second ground terminals is arranged on the resistance substrate. 3. The sub-circuit pattern (200) is a switch circuit pattern.
The potentiometer according to 1.