JP2000030912A - Multi-rotary potentiometer and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a multi-rotary potentiometer which can be improved in resolution and, at the same time, in productivity, durability, and reliability. SOLUTION: In a multi-rotary potentiometer incorporating a spiral resistor 2a, the resistor 2a is formed by applying a resistance element to the external surface of a cylindrical or columnar base material composed of a nonconductive material. Consequently, the front end of a sliding arm section can continuously smoothly slide on the surface of the resistor 2a. Therefore, the potentiometer can detect fine variation, because acquired resistance values do not change stepwise and the resolution becomes infinitely small, theoretically speaking. Moreover, the reliability on secular variation of the potentiometer can be improved, because the surface of the resistor 2a formed by applying the resistance element has high slidability and improves the durability of the sliding arm section and resistor 2 by suppressing their abrasion.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a multi-rotation potentiometer and a method of manufacturing the same.

[0002]

2. Description of the Related Art FIG. 8 shows a general structure of a multi-rotation potentiometer using a spiral resistor. As shown in FIG. 8A, this multi-rotation potentiometer
1 is provided with a resistor 102 spirally arranged in the device 1 and a ring-shaped rotator 103 having a sliding contact portion 103a slidingly contacting the resistor 102. The rotating body 103 is
It is inserted into the rotor 109a, and slides in the horizontal direction in FIG. 8A by rotating the operation unit 109b. At this time, the sliding contact portion 103a slides along the resistor 102.

[0003] Both ends of the resistor 102 are connected to a first terminal 105 and a third terminal 107, respectively.
3a 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 resistance value between the second terminal 106 and the first terminal 105 (or between the third terminal 107) can be made variable. Here, the resistor 102 is made of copper (Cu) as shown in FIG.
Ni-Cr is used for the insulated wire 102a whose surface is insulated.
And a spirally wound resistance wire 102b such as Cu-Ni.

[0004]

In such a multi-rotation potentiometer, the resistance value changes 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.

[0005] Further, the resistance wire rod 102 having the same level of hardness.
Further, since the resistance wire 102b is easily worn due to the sliding of the sliding contact portion 103a and the sliding contact portion 103a, and the adjacent resistance wires 102b are short-circuited to each other, further improvement in durability has been desired. In addition, a contact that slides on the structure [the resistor 102
Between the sliding contact portion 103a and the collector 103b, between the sliding contact portion 103a and the collector 103b, between the sliding piece 103c and the second terminal 10a.
6), the contact resistance generated in this portion increases as the sliding is repeated, and this is a factor that lowers the temporal reliability of the potentiometer.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and a multi-rotation potentiometer capable of improving the resolution, productivity, durability, and reliability thereof, and a method of manufacturing the same. The aim is to provide a method.

[0007]

According to a first aspect of the present invention, there is provided a multi-rotation potentiometer having a helical resistor inside, wherein the resistor is made of a non-conductive, cylindrical or cylindrical substrate. Is formed by applying a resistive element to the outer surface of the substrate.

According to a second aspect of the present invention, in the first aspect of the present invention, a spiral groove is formed between the spirally formed resistors.

According to a third aspect of the present invention, there is provided a method of manufacturing a multi-rotation potentiometer for manufacturing a multi-rotation potentiometer having a helical resistor inside, wherein a cylindrical or columnar substrate made of a non-conductive material is provided. A coating step of applying a resistive element on the outer surface of the resistive element, and a groove forming step of forming a spiral groove reaching the substrate on the surface of the resistive element cured after the application, and a spirally formed groove It is characterized in that a resistor is formed between them.

According to a fourth aspect of the present invention, in the third aspect of the invention, in the coating step, after the base material is inserted into the ink- or paste-shaped resistance element, one end thereof is formed along the axial direction thereof. Side at a constant speed, and then insert the base material again into the ink- or paste-type resistance element, and then pull up at a constant speed from the other end side along the axial direction, and resist the surface of the base material. It is characterized in that the element is applied.

According to a fifth aspect of the present invention, in the third aspect of the present invention, in the coating step, after the base material is inserted into the ink- or paste-shaped resistance element, one end thereof extends along the axial direction thereof. It is characterized in that the resistive element is applied on the surface of the substrate by pulling up from the side so that the pulling speed is gradually reduced.

[0012]

DETAILED 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 according to this embodiment, as shown in FIGS.
A cylindrical body 2 is arranged at the center of the inside of the cylindrical body.
A resistor 2a is formed in a spiral shape on the outer surface of. The rotating body 3 having a sliding arm 3a that comes into sliding contact with the resistor 2a is attached to the pair of rotors 9c of the shaft 9 so as to slide in the horizontal direction in FIG. 1A while rotating. . Hereinafter, each of the above-described components of the potentiometer will be described in detail. In FIG. 1 (a),
The cylindrical body 2, the rotating body 3 and the shaft 9 are not shown in cross section.

The case 1 comprises an inner case 10 made of synthetic resin and an outer case 11 made of metal. Outer case 11
Has an inner diameter substantially equal to the outer diameter of the inner case 10, and one end of the inner case 10 projects outside the outer case 11 as a cylindrical shaft holding portion 10a. In addition, inner case 1
A circular plate 4 made of a synthetic resin having a diameter equal to the outer diameter of the inner case 10 is in contact with the other end of the inner case 10.
are integrally held by a.

As shown in FIG. 3, the cylindrical body 2 has a spiral resistor 2a and a groove 2b on its outer surface. The resistor 2a is formed by dip-coating or spray-coating a resistive element made of a conductive resin on the surface of a cylindrical base made of a non-conductive body, and then grinding the spiral groove 2b reaching the base. It is formed by this.

As the resistance element for forming the resistor 2a, a thermosetting resin mixed with carbon for giving conductivity, so-called contact plastic (CP), is used. After being heated, it is baked and cured. As the substrate, a substrate having heat resistance that can withstand heating and firing is used. Since it is necessary to make the resistance per unit length of the resistor 2a constant, the resistor 2a
It is important that the thickness of this layer be constant over the entire length of the helix.

In forming the resistor 2a, as a method of applying a resistance element to the outer surface of the base material so that the thickness of the layer becomes uniform, there is an application method by dip coating or spray coating. Dip coating is a method in which a resistive element is applied to the outer surface of the base material by dipping the base material into a resistive element in the form of an ink or a paste and then pulling it up. on the other hand,
Spray coating is a method of spraying and applying the above-described ink or paste-like resistance element to the outer surface of a base material using a spray gun or the like.

Hereinafter, a procedure for forming the resistor 2a by dip coating will be described in detail. The method of forming the resistor 2a described here includes a painting step and a groove forming step.

In the coating step, the resistive element is applied to the outer surface of the base material by dipping the base material into a resistive element in the form of an ink or paste and then pulling up the resistive element.
In order to make the thickness of the layer of the resistance element uniform, it is performed as follows. First, the base material is immersed in the resistance element, and is pulled up at a constant speed from one end side along the axial direction of the base material.

At this time, the resistive element applied to the outer surface of the base material gathers at the other end due to its own weight, and the thickness of the layer at one end is smaller than the thickness of the layer at the other end. For this reason, the base material is immersed in the resistance element again, and then pulled up from the other end side along the axial direction of the base material. In addition, baking for a short time is performed between the first dip coating and the second dip coating as necessary. By doing so, the thickness of the layer as a whole can be made uniform. The thickness of the formed resistor 2a depends on the viscosity and the pulling speed of the ink or paste resistor element.

The resistance element uniformly applied to the outer surface of the substrate is cured by heating and baking. However, in this state, since the resistance element is applied to the entire outer surface of the base material, the spiral resistor 2a has not been formed yet.
Therefore, in the groove forming step, a spiral groove 2b reaching the base material is formed on the surface of the applied resistive element,
A spiral resistor 2a is formed.

In the groove forming step, a spiral groove 2b is formed on the surface of the cured resistive element by mechanical grinding or laser processing. At this time, the width of the resistor 2a formed between the grooves 2b is made constant. If the width of the resistor 2a is not constant, the resistance value per unit length will not be constant even if the thickness of the layer is constant. Also, at the boundary between the resistor 2a and the groove 2b on both sides, the resistance element layer forming the resistor 2a is prevented from being chipped or peeled off.

According to this method, the resistor 2a having a uniform layer thickness can be easily formed without requiring a complicated device or control.

In the dip coating described above, the base material is immersed in the resistance element, pulled up from one end thereof, then immersed again in the resistance element and pulled up from the other end. The process can be simplified by pulling up the substrate only once. In this case, after the base material is immersed in the ink-like or paste-like resistance element, the base material is pulled up from one end side in the axial direction of the base material so that the pulling speed gradually decreases. If the resistive element is formed by dip coating, the layer thickness of the resistive element after coating tends to increase as the pulling speed increases, so that the final resistive element layer thickness can be made uniform. It can be.

According to this method, variable control of the pull-up speed is required, but pull-up only needs to be performed once, and a resistor 2a having a uniform layer thickness is required without requiring a complicated device. Can be easily formed.

In any of the above-described methods, by forming a resistor 2a by applying a resistor, the productivity of the resistor 2a and, consequently, the productivity of the potentiometer are dramatically improved. Can be done.
On the other hand, in the case of the conventionally used resistor 102 as shown in FIG. 8B, the number of parts required to form the resistor 102 is large, the process becomes complicated, and much labor and cost are required. Was something. In particular, when the potentiometer is of a multi-rotation type, the length of the resistor 102 becomes longer, so that the conventional process is particularly remarkable in that the steps become complicated and costly.

Further, since the resistor 2a is formed by a uniformly applied resistance element, when the contact position of the sliding arm 3a to the resistor 2a is changed to make the resistance variable, The resolution is theoretically infinitely small. For this reason, very minute fluctuations can be detected. Further, since the resistor 2a is formed of a uniformly applied resistive element, the surface of the resistor 2a is a smooth surface having excellent self-lubricating properties with excellent slidability.
a and the tip of the sliding arm portion 3a that is in sliding contact therewith are less likely to be worn, thereby improving durability and reliability over time.

A silver paste is applied to both ends of the resistor 2a formed as described above to form a contact layer 2g, as shown in FIG. This contact layer 2
g is further laminated on the resistance element layer. The contact layer 2g serves as an electrode for applying a voltage to both ends of the resistor 2a. In forming the contact layer 2g, the paste is heated and baked using a silver paste to be cured. The contact layer 2g is formed in order to accurately obtain a detectable angle (effective electrical angle) and to electrically connect the terminal arm 5a of the first terminal 5 and the terminal piece 7d of the third terminal 7 described later. This is for making it easier and more reliable. The resistor 2a exhibits a constant resistance per unit length in a range between the contact layers 2g at both ends.

As shown in FIGS. 1 and 3, the cylindrical body 2 has its base end 2e fitted in a pair of holding walls 4e of the plate 4, and has the first terminal 5 and the first terminal 5 attached to the plate 4. It is gripped and fixed by the third terminal 7.
2 and 3, both ends of the resistor 2a are connected to the first terminal 5 in the contact layer 2g, respectively, as shown in FIGS.
Are electrically connected to the terminal arm portion 5a and the terminal piece 7d of the third terminal 7. FIG. 3 (a) shows a state in which each member is separated, but FIGS. 3 (b) and 3 (c) show the cylindrical body 2
It is shown so that the positional relationship between the first terminal 5 and the third terminal 7 can be understood.

As shown in FIG. 3, the first terminal 5 is a metal plate bent in a hook shape, one end of which protrudes outside from the plate 4, and the other end is branched into three. A pair of terminal arms 5a and gripping arms 5b are formed. The grip arm 5b is inserted into the through hole 2c of the cylindrical body 2, the terminal arm 5a is in contact with the contact layer 2g of the resistor 2a, and the first terminal 5 grips the cylindrical body 2 and It is electrically connected to one end of the body 2a.

On the other hand, as shown in FIG. 3, the third terminal 7 is also a metal plate bent in a hook shape, one end of which protrudes out of the plate 4 and the other end branches into three. Thus, a pair of gripping arm portions 7a and terminal arm portions 7b are formed. The terminal arm 7b is inserted into the through hole 2c of the cylindrical body 2, and is electrically connected to the other end of the resistor 2a via the lead wire 7c and the terminal piece 7d. In addition, the terminal piece 7
d is fitted into a concave portion 2d formed at the other end of the resistor 2a, and is in contact with the contact layer 2g in the concave portion 2d. Further, the cylindrical body 2 has its outermost end 2f gripped by a pair of gripping arm portions 7a and terminal arm portions 7b.

The first terminal 5 and the third terminal 7 are
Are inserted into the insertion holes 4b and 4d respectively formed in the holes. Each of the first terminal 5 and the third terminal 7 has a hole. As shown in FIG. 2C, the bosses 4f of the plate 4 are inserted into the holes, and the boss 4f is caulked by heating. The first terminal 5 and the third terminal 7 are fixed to the plate 4 respectively.

As shown in FIGS. 2 and 3, the plate 4 is a substantially disk-shaped member formed of a synthetic resin. A pair of holding walls 4 e for holding the cylindrical body 2 are provided upright at the center of the inner surface of the plate 4. The plate 4 has an insertion hole 4c in addition to the above-described insertion holes 4b and 4d. The L-shaped second terminal 6 is inserted into the insertion hole 4c. Second terminal 6
Has one end protruding out of the plate 4 and the other end in contact with the back surface of the plate 4, and is electrically connected to one end 8b of a coil spring 8 described later at a solder portion 6a.

The rotating body 3 having the sliding arm 3a that comes into sliding contact with the resistor 2a is a member made of a substantially C-shaped synthetic resin, as shown in FIG. 2 (a) and FIG. One surface side of the rotating body 3 is formed in a circular concave shape, and a part of a coil spring described later is accommodated in this portion. The other end 8c of the coil spring 8 penetrates from the inside to the outside of the rotating body 3 and is electrically connected to the base end of the sliding arm 3a at the solder 3b.

The sliding arm 3a is an elastically deformable metal plate, the tip of which is rounded so as to smoothly slide on the resistor 2a. When the sliding arm 3a comes into sliding contact with the resistor 2a, the tip thereof is reliably brought into contact with the resistor 2a by the elastic restoring force of the sliding arm 3a itself. Rotating body 3
The cylindrical body 2 is inserted into the central hole of the, and a pair of guide projections 3c is protruded toward the hole.

The pair of guide projections 3c is formed in the groove 2
It is formed as a curved convex portion corresponding to b. For this reason, when the rotating body 3 is attached to the cylindrical body 2,
Each of the guide projections 3c slides in the groove 2b, and guides rotation and sliding of the rotating body 3.
Further, a pair of notches 3 d facing the central hole of the rotating body 3.
Are formed, and a pair of rotors 9c of the shaft 9, which will be described later, are inserted through the cutouts 3d. For this reason, when the shaft 9 is rotated, the rotating body 3 slides while being rotated.

The coil spring 8 is, as shown in FIG.
The spring is such that the central coil portion 8a becomes dense in a natural length state. One end 8b of the coil spring 8 is
The other end 8c is once extended in the direction of the central axis of the coil spring 8 and then outwardly bent in a hook shape. Further, the coil spring 8 has a mounting portion 8d which is bent in a U-shape toward the center axis of the coil spring 8 at a position facing the one end 8b.

The coil spring 8 not only has one end 8b fixed to the second terminal 6 at the solder portion 6a, but also has a mounting portion 8d locked to a boss 4g protruding from the inner surface of the plate 4, and 4 g is also fixed by caulking by heating. When the rotating body 3 is rotated, the coil spring 8 is extended while rotating the other end 8c in the R direction in FIG. 6A, that is, in a direction in which the rotation of the coil spring 8 is twisted.

As described above, in this potentiometer, the sliding arm 3a and the second terminal 6 are connected to the coil spring 8
Are electrically connected via the contact, so that the sliding contact is only between the resistor 2a and the sliding arm 3a, it is possible to prevent an increase in contact resistance and improve the reliability over time. be able to.

When designing the coil spring 8, it is necessary to pay attention to the characteristics and shape of the spring. While the leading end of the sliding arm 3a spirally slides from one end to the other end of the resistor 2a, the number of rotations at which the other end 8c of the coil spring 8 rotates and the other end 8c are shown in FIG. ) Considering the amount of displacement in the middle and lateral directions, even if the rotation and displacement are the largest, the coil spring 8
Is kept within the elastic range. Rotating the coil spring 8 in the direction R in FIG.
Coil spring 8 than when rotated in the opposite direction
This is because the residual stress acting on the substrate can be reduced.

As shown in FIG. 7, the rotor 9c inserted into the notch 3d of the rotating body 3 is connected to the operating unit 9a via a non-conductive disk 9b made of synthetic resin or the like. Thus, the shaft 9 is formed. Rotor 9
c is a metal plate which is curved about its rotation center axis and does not easily bend, and is integrated with the disk portion 9b by insert molding when forming the disk portion 9b. The rotor 9c does not come into contact with the resistor 2a. Disc 9b
Has a mounting hole 9f formed in the center thereof. The mounting protrusion 9e of the operating portion 9a is fitted into the mounting hole 9f, the mounting protrusion 9e is caulked, and the operating portion 9a, the disk portion 9b and the rotor 9c are formed. Are combined.

The non-conductive disk portion 9b is interposed between the operating portion 9a and the rotor 9c because the potential of the operating portion 9a is kept at the potential of the coil spring 8 even if the rotor 9c and the coil spring 8 come into contact with each other. This is so as not to be affected. When incorporated in the potentiometer, the pair of rotors 9c engage with the notches 3d of the rotating body 3 described above, and rotate the operation unit 9a from outside the case 1 to rotate via the rotor 9c. The body 3 can be rotated. The rotor 9c guides the sliding of the rotating body 3 when the rotating body 3 slides in the horizontal direction in FIG.

The operating portion 9a is held by a shaft holding portion 10a, and one end of the operating portion 9a extends outside the case 1.
A metal bearing 9d for smoothly rotating the operation unit 9a is press-fitted or adhered inside the shaft holding unit 10a, thereby suppressing backlash of the operation unit 9a. Further, a screw portion 10b used for fixing the potentiometer to various portions is formed on the outer surface of the shaft holding portion 10a.

At the time of assembling the potentiometer composed of the above-described components, the cylindrical body 2, the rotating body 3, the plate 4, the first terminal 5, the second terminal 6, the third terminal 7, and the coil spring 8 are assembled in advance to form a resistor. It is manufactured as an assembly. In addition, the shaft 9 shown in FIG. The resistor assembly is assembled inside the case 1 to which the shaft 9 is attached, and finally the claw portion 11a of the outer case 11 is bent into the concave portion 4a of the plate 4 to complete the assembly.

When using the potentiometer described above, a voltage is applied between the first terminal 5 and the third terminal 7, and a voltage is applied between the first terminal 5 (or the third terminal 7) and the second terminal 6. And take out the divided voltage. At this time, the resistance between the first terminal 5 (or the third terminal 7) and the second terminal 6 is changed by rotating the operation unit 9a to change the contact position of the sliding arm 3a with the resistor 2a. Since it can be changed, the partial pressure taken out can be changed.

The multi-rotation potentiometer of the present invention is not limited to the above embodiment. For example, in the potentiometer in the embodiment described above,
Although the resistor 2a is formed on the outer surface of the cylindrical body 2, the inner diameter of the cylindrical body 2 is increased so that the resistor 2a is formed on the inner surface of the cylindrical body 2.
May be formed. When the resistor 2 a is formed on the inner surface of the cylindrical body 2, the cylindrical body 2 and the inner case 10 may be integrally formed.

Further, instead of the above-mentioned cylindrical body 2, a spiral resistor may be formed on the outer surface of the cylindrical body by using a cylindrical member having no through hole therein. Furthermore, in the potentiometer of the above-described embodiment, the spiral resistor 2a is formed by grinding the groove 2b. However, in the invention described in claim 1, the spiral resistor 2a is formed before the resistive element is applied. Masked,
After applying the resistive element, this masking may be removed to form the spiral resistor 2a.

[0048]

According to the first aspect of the present invention, since the resistor is formed by applying a resistive element to the surface of a cylindrical or columnar base material, the tip of the sliding arm portion has a resistance. It slides smoothly on the surface of the body steplessly. Therefore, the extracted resistance value does not change stepwise, and theoretically the resolution becomes infinitely small, and a minute change can be detected. In addition, the surface of the resistor formed by applying the resistance element has excellent slidability, suppresses abrasion of the sliding arm portion and the resistor, improves durability, and improves reliability over time. be able to. Further, since the resistor is formed by applying a resistor, the productivity of the resistor can be significantly improved as compared with the past, and the productivity of the potentiometer itself can be improved.

According to the second aspect of the present invention, since the spiral groove is formed, the rotation and sliding of the sliding arm contacting the resistor can be guided by the groove.

According to the third aspect of the present invention, since the coating step of applying the resistor is provided, the productivity of the resistor can be significantly improved as compared with the prior art. You can improve your own productivity. Also, in the manufactured potentiometer, since the tip of the sliding arm slides smoothly on the surface of the resistor steplessly and smoothly, the resistance value to be taken out does not change stepwise, and it is theoretically possible. The resolution becomes infinitely small, and minute fluctuations can be detected. Furthermore, since the surface of the resistor formed by applying the resistive element has excellent slidability, wear of the sliding arm and the resistor is suppressed, and the manufactured potentiometer has durability and reliability over time. Is improved. Furthermore, since the method includes the step of forming a groove, the manufactured potentiometer can guide the rotation and sliding of the sliding arm contacting the resistor by the groove.

According to the fourth aspect of the present invention, a potentiometer having a resistor having a uniform layer thickness can be easily manufactured without requiring a complicated device or control. In addition, the manufactured potentiometer has high accuracy because the thickness of the resistor layer is uniform.

According to the fifth aspect of the present invention, the substrate is pulled up only once in the coating process, and the resistor having a uniform layer thickness is provided without requiring a complicated device. The potentiometer can be manufactured easily. In addition, the manufactured potentiometer has high accuracy because the thickness of the resistor layer is uniform.

[Brief description of the drawings]

FIG. 1A is a sectional view showing an embodiment of a multi-rotation potentiometer of the present invention, and FIG. 1B is a right side view of the same.

2A is a left side view of a resistor assembly in one embodiment of the multi-rotation potentiometer of the present invention, FIG. 2B is a front view of the resistor assembly, and FIG.
It is a XX sectional view taken on the line in (b).

3A is an exploded plan view of a cylindrical body and a plate in one embodiment of the multi-rotation potentiometer of the present invention, FIG. 3B is a front view of the cylindrical body, and FIG. It is.

FIG. 4 is a side view of a cylindrical body in one embodiment of the multi-rotation potentiometer of the present invention.

FIG. 5A is a left side view of a rotating body in one embodiment of the multi-rotation potentiometer of the present invention, and FIG. 5B is a sectional view taken along line YY in FIG.

FIG. 6 shows a natural state of a coil spring in one embodiment of the multi-rotation potentiometer of the present invention, wherein (a) is a left side view, (b) is a front view, and (c) is a right side view.

FIG. 7 is an exploded side view of a shaft and a plate in one embodiment of the multi-rotation potentiometer of the present invention.

8A and 8B show a conventional multi-rotation potentiometer, in which FIG. 8A is a sectional view, and FIG. 8B is an enlarged side view in which a part of a resistor is sectioned.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... case, 10 ... inner case, 11 ... outer case, 2 ... resistance cylinder, 2a ... resistor, 2b ... groove part, 3 ... rotating body, 3a
... Sliding arm, 5 ... First terminal, 6 ... Second terminal, 7 ... Third terminal, 8 ... Coil spring.

 ──────────────────────────────────────────────────の Continued on the front page F term (reference) 5E030 AA20 BA06 CA04 CB01 CC04 CC12 CE05 FA04 5E032 AB10 BA06 BB04 CA11 CB00 CC04 CC06 CC11

Claims (5)

[Claims] 1. A multi-rotation potentiometer having a helical resistor inside, wherein the resistor is formed by applying a resistive element to a surface of a cylindrical or columnar base made of a non-conductive material. A multi-rotation potentiometer. 2. The method according to claim 1, wherein the resistor is formed in a spiral shape.
The multi-rotation potentiometer according to claim 1, wherein a spiral groove is formed. 3. A multi-rotation potentiometer manufacturing method for manufacturing a multi-rotation potentiometer having a helical resistor inside, wherein a resistive element is applied to a surface of a cylindrical or columnar base made of a non-conductive material. And a groove forming step of forming a spiral groove reaching the substrate on the surface of the resistive element cured after application, wherein the resistance is formed between the spirally formed grooves. A method of manufacturing a multi-rotation potentiometer, comprising forming a body. 4. In the coating step, after inserting the base material into the resistive element in the form of an ink or a paste, the base material is pulled up from one end side along the axial direction at a constant speed. The method according to claim 3, wherein after re-inserting into the resistive element in the form of ink or paste, the resistive element is pulled up from the other end side along the axial direction at a constant speed to apply the resistive element to the surface of the base material. A method for manufacturing the multi-rotation potentiometer according to the above. 5. In the coating step, after inserting the base material into the resistive element in the form of ink or paste, the base material is pulled up from one end side along the axial direction so that the pulling speed is gradually reduced. 4. The method for manufacturing a multi-rotation potentiometer according to claim 3, wherein the resistance element is applied to a surface of the base material.