JP2000306708A - Multiple rotation type potentiometer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a multiple rotation type potentiometer which improves resolution, productivity, durability and reliability. SOLUTION: This multiple rotation type potentiometer is equipped with a resistor holder 10, which has a spiral resistor holding trench 10a and is divided into a plurality of parts, a spiral resistor 2 accommodated in the trench 10a, in which resistor a conductive plastic layer is laminated on the surface of a tape-like insulating base material, and a rotating body 3 having a sliding contact part 3a which slides on the surface of the resistor 2, while being in contact with the surface.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-rotation potentiometer.

[0002]

2. Description of the Related Art The general structure of a multi-rotation potentiometer is shown in FIG. As shown in FIG. 11A, this multi-rotation potentiometer has a ring shape having a resistor 102 spirally arranged in a case 101 and a sliding contact portion 103a slidingly contacting the resistor 102. Rotator 103
And The rotating body 103 is inserted through the rotor shaft 109a, and rotates while sliding in the horizontal direction in the figure by rotating the shaft 109b, so that the sliding contact portion 103a slides along the resistor 102. Let it. Both ends of the resistor 102 are connected to the first terminal 105 and the third terminal 107, respectively.
It is connected to the second terminal 106 via the collector 103b and the sliding piece 103c. By changing the contact position of the sliding contact portion 103a with the resistor 102, the second terminal 1
06 and the first terminal 105 (or the third terminal 107) can be made variable. Here, the resistor 10
As shown in FIG. 11 (b), a resistance wire 102b such as Ni-Cr or Cu-Ni is spirally wound around an insulated wire 102a having a surface of a copper (Cu) wire insulated as shown in FIG. is there.

[0003]

In such a multi-rotation potentiometer, the resistance value varies depending on the contact position between the resistance wire 102b wound around the resistor 102 and the sliding contact portion 103a. The values change stepwise. The resistance value of one step of the resistance value that changes in a stepwise manner is the resolution of the potentiometer, but there has been a demand for further reducing the resolution in order to detect minute fluctuations. In addition, such a multi-rotation potentiometer requires a great deal of time to manufacture the above-described resistor 102, which is an obstacle to improving the productivity of the entire potentiometer. In addition, since the resistance wire 102b having the same level of hardness and the sliding contact portion 103a are slid, the resistance wire 102b is easily worn, and the adjacent resistance wire
Further improvement in durability has been desired, such as short-circuiting between 2b. Also, the contacts that slide on the structure (between the resistor 102 and the sliding contact portion 103a, between the sliding contact portion 103a and the collector 103b,
c and the second terminal 106), and the contact resistance generated at this portion increases as the sliding is repeated, which is a factor that deteriorates the temporal reliability of the potentiometer.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to provide a multi-rotation potentiometer capable of improving resolution, productivity, durability, and reliability. With the goal.

[0005]

According to a first aspect of the present invention, there is provided a resistor holder having a spiral resistor holding groove extending along an inner surface thereof and divided into a plurality of resistor holders. A spiral resistor having a conductive plastic layer laminated on the surface of a tape-like insulating base material, and a rotating body having a sliding contact portion that slides on the surface of the resistor. .

[0006] The resistor according to the first aspect of the present invention,
It has a tape-like form in which a conductive plastic layer (hereinafter also referred to as “CP layer”) is laminated on an insulating base material, and a sliding contact portion slides continuously on the surface of the resistor. Therefore, according to the present invention, the extracted resistance value does not change stepwise, theoretically the resolution becomes infinitely small, and a minute change can be detected. In manufacturing the tape-shaped resistor, a CP layer is laminated on a film-shaped insulating base material,
It is only necessary to cut this into a tape shape, and its manufacture is easy and contributes to the improvement of the potentiometer productivity.

Further, the surface of the CP layer is excellent in slidability, can suppress abrasion of the sliding contact portion and the resistor, improve durability, and improve reliability over time. Further, since the resistor has a tape shape, the contact state between the surface of the resistor and the sliding contact portion is stable, and the reliability can be improved from this point as well. In addition, as a result of employing the split-type resistor holder, a spiral resistor holding groove can be easily formed in the resistor holder, which contributes to a reduction in manufacturing cost. In addition, the spiral resistor holding groove functions as a guide for the sliding contact portion, and can stably slide the sliding contact portion with respect to the resistor.

According to the invention of claim 2, it is preferable that the resistor is brought into close contact with the inner surface of the resistor holder by its elastic restoring force. In this case, the resistor comes into close contact with the inner surface of the case due to the elastic restoring force of the resistor itself, and the resistor is held in a stable state. Also, while the sliding contact portion slides on the surface of the resistor, the resistor is in close contact with the inner surface of the case, so that the sliding contact portion can slide smoothly on the resistor surface. it can.

According to a third aspect of the present invention, the resistor holding groove includes:
It is preferable that the width of the bottom is substantially equal to the width of the resistor, and the width of the opening is wider than the width of the bottom.
In this case, when the resistor is housed in the resistor holding groove, the resistor can be easily housed while being guided by the resistor holding groove, leading to an improvement in productivity. Further, since the width of the bottom of the resistor holding groove is substantially equal to the width of the resistor, the resistor can be held securely.

According to a fourth aspect of the present invention, it is preferable that the resistor holders are connected to each other by the concave and convex fitting of the boss portion and the boss receiving portion. With this configuration, the divided resistor holders can be easily and reliably assembled and fixed.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of a multi-rotation potentiometer according to the present invention will be described with reference to the drawings.

In the multi-rotation potentiometer shown in FIGS. 1 and 2, a case 1 has a resistor 2 formed in a spiral shape in a tape shape and a sliding contact portion 3a slidingly contacting the resistor 2. Rotating body 3 is disposed. The rotating body 3 slides along the rotor axis 9a of the shaft 9 while rotating in the horizontal direction in the drawing. The case 1 includes a housing 1 molded with a resistor holder 10 made of synthetic resin and molded.
It consists of one. At the rear end of the housing 11, a circular plate 4 having a diameter equal to the outer diameter of the resistor holder 10 is fixed via an adhesive R.

The resistor 2 is, as shown in FIGS. 3 and 4,
A conductive plastic layer (hereinafter, also referred to as “CP layer”) 2b is formed on the insulating base material 2a,
At both ends of the resistor 2, a contact layer 2c is formed on the CP layer 2b.
Are laminated. The CP layer 2b is made of a thermosetting resin mixed with carbon in order to secure conductivity.
It is applied on top and cured by heating and baking. As the insulating base material 2a, a film having heat resistance enough to withstand heating and firing and having appropriate flexible deformability is used.

The contact layer 2c is a silver (Ag) pattern that serves as an electrode for applying a voltage to both ends of the resistor 2. When the contact layer 2c is formed, it is cured by heating and baking using a silver paste. The contact layer 2c is formed in order to obtain a detectable angle (effective electrical angle) by regulating the length L of the CP layer 2b, and to easily and reliably connect with the terminal springs 5b and 7b described later. Done in When the CP layer 2b and the contact layer 2c are formed by a coating method such as a screen printing method or a drawing method, a uniform layer thickness is realized. When the thickness of the CP layer 2b is made uniform, it is possible to appropriately prevent the resistance value per unit length from being different.

When the resistor 2 is manufactured, a CP layer 2b is formed on a sheet-like insulating base material 2a, and contact layers 2c are formed on opposite end edges. Can be easily manufactured at once. On the other hand, in the case of the resistor 102 conventionally used as shown in FIG. 11B, the number of components required to form the resistor 102 is large, which not only complicates the process but also one by one. Because it has to be manufactured,
It was very laborious and costly. This means that if the potentiometer is multi-turn, the resistor 102
This is particularly noticeable because the length of In contrast, the multi-rotation potentiometer shown in FIG. 1 can dramatically improve the productivity.

The divided resistor holder 10 made of resin to which the resistor 2 is attached is formed by assembling two half-cylindrical resistor holder portions 10A, as shown in FIGS. Is done. And the spiral resistor 2 is
The resistor is held in the resistor holder 10 so as to be sandwiched between the two resistor holders 10A.

As shown in FIGS. 7 and 8, a spiral resistor holding groove 10 a is formed on the inner surface of the resistor holder 10. Each of the resistor holder sections 10A has the same shape, thereby achieving the sharing of parts. Further, on the left and right connecting surfaces 10b of each of the resistor holder portions 10A, boss portions 15A, 15B projecting therefrom and boss receiving portions 16A, 16B in the form of vertical grooves into which the boss portions 15A, 15B of the other party are fitted are formed. (2) The two concave and convex resistor holders 10A can be fitted to each other in a concave-convex manner so that they can be securely assembled to each other. In this case, the boss 15A of the one resistor holder 10A and the boss receiving portion 16A of the other resistor holder 10A are fitted together, and similarly, the boss 15B and the boss receiving portion 16B are fitted together. .

On the left and right connecting surfaces 10b, the distance L1 between the boss portion 15A and the boss receiving portion 16A and the boss portion 1A
The interval L2 between 5B and the boss receiving portion 16B is different. This is a measure for always keeping the assembling direction constant when assembling the two resistor holder portions 10A having the same shape. As a result, an erroneous recognition of assembly by the operator can be eliminated, and a reliable spiral resistor holding groove 10a can be created in the resistor holder 10.

The width of the bottom 10c of the resistor holding groove 10a is substantially equal to the width of the resistor 2, whereas the width of the opening 10d of the resistor holding groove 10a is larger than the width of the bottom. Is also widely formed. For this reason, the cross section of the resistor holding groove 10a has a concave shape gradually narrowing toward the bottom, and when the resistor 2 is stored in the resistor holding groove 10a, the resistor 2 is guided, so that the storing operation is easy. .

The resistor 2 is inserted into the resistor holding groove 10a.
Is accommodated, the resistor 2 is in the form of a tape and adheres tightly to the inner surface of the case 1 by its own elastic restoring force, so that the sliding contact portion 3a slides smoothly on the surface of the tape-shaped resistor 2. Can be. Further, the resistor 2 holds a spiral form along the resistor holding groove 10a by its own elastic restoring force.

The CP layer 2b of the resistor 2 is
Formed on the entire surface of the resistor 2,
When the contact position of the sliding contact portion 3a with the layer 2b is changed to change the resistance value, the resolution theoretically becomes infinitely small. For this reason, a minute change can be detected. In addition, since the resistor 2 is in a tape shape, it has excellent slidability, is less likely to be worn, and has improved durability and reliability over time. In addition, since the resistor 2 has a tape shape, the contact state with the sliding contact portion 3a is stable, and the reliability is improved in this respect as well. The width of the resistor 2 held in the resistor holding groove 10a is equal to the width of the bottom of the resistor holding groove 10a. When stored in 10a, the position is reliably maintained.

The housing state of the resistor 2 in the resistor holding groove 10a is such that the surface side of the CP layer 2b is inside the spiral, but it is necessary to pay attention to the spiral diameter at this time.
If the helical diameter is too small, the stress applied to the CP layer 2b will increase, and cracks will easily occur in the CP layer 2b. On the other hand, if the helical diameter is too large, the elastic restoring force of the resistor 2 does not act effectively, and it is difficult to firmly adhere to the bottom of the resistor holding groove 10a.

Both ends of the resistor 2 are respectively held and fixed to the resistor holder 10 by two terminal springs (not shown) in the contact layer 2c, and are electrically connected to the first terminal 5 and the third terminal 7, respectively. I have. And each terminal spring part is integrally formed in the 1st terminal 5 and the 3rd terminal 7, respectively. Note that the resistor holder 10 is connected via a lead wire.
May be connected to the terminals 5 and 7 in some cases. In this potentiometer, both the first terminal 5 and the third terminal 7 are configured to be exposed from the insertion holes 17 and 18 of the plate 4 (see FIG. 10). Plate 4
Is a substantially disc-shaped member formed of a synthetic resin, as shown in FIG. An L-shaped second terminal 6 is fixed to the plate 4.
Are exposed to the outside like the first terminal and the third terminal 7.

As shown in FIG. 9 and FIG.
The arm 3b has a sliding contact 3a formed at the tip thereof for sliding contact with the resistor 2, a disk 3c to which the arm 3b is attached in a cantilever state, and a disk 3c.
Is attached to the main body 3d. The sliding contact 3a is formed in a brush shape with the tip of the arm 3b branched into two. The arm 3b is formed of a metal plate having an elastic restoring force. Also, the disk portion 3c
It is formed of a conductive metal and has a square hole at the center. The disk portion 3c is connected to a tongue piece formed on a part of the periphery of the disk portion 3c in a state where the base end of the above-described arm portion 3b is secured in conductivity by welding.

The disk 3c is fixed to the main body 3d by thermal caulking of the projections 3g, 3g protruding from the main body 3d. A pair of guide projections 3e, 3e having a phase angle of 180 degrees are protruded in the radial direction on the outer periphery of the main body 3d. The pair of guide projections 3e, 3e are formed as projections corresponding to the concave grooves of the resistor holding groove 10a. For this reason, when the rotating body 3 is attached to the resistor holder 10, the guide projections 3e slide in the resistor holding groove 10a, respectively, and guide the rotation and sliding of the rotating body 3. At the center of the rotating body 3, a rectangular insertion hole 3f is formed, and by inserting the rotor shaft 9a having a rectangular cross section into it, the shaft 9 and the rotating body 3 rotate integrally.

Further, between the rotating body 3 and the plate 4,
A tension spring in which a coil spring 8 is disposed and a central coil portion is dense in a natural length state. Coil spring 8
Has one end extending linearly so as to be parallel to the center axis of the coil spring 8, and the other end radially extending outward from the center axis of the coil spring 8. However, when the coil spring 8 is incorporated in the potentiometer,
Even when the rotating body 3 is positioned closest to the plate 4, the coil spring 8 is stretched to some extent, and a gap is always formed between the winding circumferences of the coil spring 8.

One end of the coil spring 8 is connected to the disk portion 3c.
, But the other end is soldered to the second terminal 6 attached to the plate 4. For this reason, the sliding contact 3a and the second terminal 6 are connected to the arm 3b.
It is directly connected via the disk part 3c and the coil spring 8. As a result, in this potentiometer, the sliding contact is only between the resistor 2 and the sliding contact portion 3a, so that the contact resistance can be prevented from increasing and the reliability over time can be improved.

When using the potentiometer described above, a voltage is applied between the first terminal 5 and the third terminal 7, and a voltage is divided between the first terminal 5 (or the third terminal 7) and the second terminal. Take out the applied voltage. At this time, by rotating the shaft 9, the contact position of the sliding contact portion 3a with the resistor 2 is changed, and the resistance between the first terminal 5 (or the third terminal 7) and the second terminal is changed. Therefore, the partial pressure to be taken out changes.

The multi-rotation potentiometer of the present invention is not limited to the above embodiment. For example, the potentiometer in the above-described embodiment includes the resistor 2
Is formed such that the CP layer comes inside the spiral of the resistor 2, but the resistor is arranged so that the CP layer comes outside the spiral, and the sliding contact portion is formed along the outer surface of the resistor. It is also possible to slide. Further, the resistor holder 10 is
The invention is not limited to the division, and may be three or more.

[0030]

The multi-rotation potentiometer according to the present invention has a spirally shaped resistor holding groove along the inner surface and is divided into a plurality of resistor holders. The resolution is improved by providing a helical resistor having a conductive plastic layer laminated on the surface of the base material and a rotating body having a sliding contact portion that slides on the surface of the resistor. And its productivity, durability and reliability can be improved.

[Brief description of the drawings]

FIG. 1 is a sectional view showing one embodiment of a multi-rotation potentiometer according to the present invention.

FIG. 2 is a rear view of the potentiometer shown in FIG.

FIG. 3 is a plan view showing a resistor applied to the potentiometer of the present invention.

FIG. 4 is an enlarged perspective view of a main part of the resistor shown in FIG. 3;

FIG. 5 is a front view showing a divided resistor holder.

FIG. 6 is a side view of the resistor holder and the resistor shown in FIG. 5;

FIG. 7 is a side view showing one of the two resistor holder holders.

FIG. 8 is a front view of the resistor holder shown in FIG. 7;

FIG. 9 is a side view showing an assembly in which a coil spring is interposed between a rotating body and a plate.

FIG. 10 is a front view of the assembly shown in FIG. 9;

11A and 11B show a conventional multi-rotation potentiometer, in which FIG. 11A is a cross-sectional view and FIG. 11B is an enlarged partial cross-sectional side view of a resistor.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Case, 2 ... Resistor, 2a ... Insulation base material, 2b ...
Conductive plastic layer (CP layer), 3 ... rotating body, 3a ... sliding contact part, 10 ... resistor holder, 10A ...
Resistor holder portion, 10a: resistor holding groove, 10c: bottom portion, 10d: opening portion, 11: housing, 15: boss portion, 16: boss receiving portion.

Claims (4)

[Claims] 1. A resistor holder having a spiral resistor holding groove extending along an inner surface thereof and divided into a plurality of pieces, a conductive plastic layer housed in the resistor holding groove and on a surface of a tape-shaped insulating base material. And a rotator having a sliding contact portion that slides on the surface of the resistor. 2. The multi-rotation potentiometer according to claim 1, wherein said resistor is brought into close contact with an inner surface of said resistor holder by its elastic restoring force. 3. The resistor holding groove has a width at a bottom portion substantially equal to a width of the resistor, and a width of an opening thereof is wider than a width of the bottom portion. The multi-rotation potentiometer according to claim 1. 4. The multi-rotation potentiometer according to claim 1, wherein the resistor holders are connected to each other by a concave-convex fitting of a boss portion and a boss receiving portion.