variable resistor

Abstract

The present application provides a variable resistor that realizes an increase in the number of operations due to long sliding life. The variable resistor (1) includes a substrate (2), a resistor body (3) that contains carbon powder and a binder resin that solidifies the carbon powder and is applied to the surface of the substrate (2), a conductive brush (4) that slides on the surface of the resistor body (3), and a lubricant (5) that is applied to the surface of the resistor body (3), the lubricant (5) having a molecular structure in which polar functional groups are present at one end and the other end of a chain structure of covalent bonds that contain multiple carbon atoms, and the number of hydrogens bonded to the multiple carbon atoms is greater than the number of fluorines bonded to the multiple carbon atoms.

Description

Technical Field

[0001] This invention relates to variable resistors used in controllers and the like for gaming devices. Background Technology

[0002] In recent years, due to the diversification of game operations, the requirements for controllers such as analog joysticks used in game devices have gradually increased. For example, there is a need to increase the number of times the controller can operate due to the extended sliding life.

[0003] In controllers used in gaming devices, a variable resistor is used to change the output voltage in accordance with the operation. The variable resistor changes its resistance value based on the movement of a conductive brush, such as a metal slider, on a resistive body (surface) through the operation of the controller, thus changing the output voltage.

[0004] The resistive element that slides on the surface of the conductive brush is a film (composite film) of a composite material of resin and carbon powder. With each slide, the wear at the contact points within the resistive element increases. If wear progresses, the contact with the conductive brush becomes unstable, generating output noise. To counteract this output noise and improve the lubrication of the contact points between the carbon resistive element and the conductive brush (contact), a fluorine-based lubricant is applied to the sliding contact points to reduce wear.

[0005] For example, Patent Document 1 describes a sliding resistor (variable resistor) designed to ensure stable electrical conduction, maintain excellent sliding resistance over a long period, and minimize sliding noise. This sliding resistor includes a resistive element disposed on the surface of a resistive substrate and a contact that slides on the resistive element. A lubricating layer formed of a fluorinated lubricant is provided on the entire surface of the resistive substrate where the resistive element is disposed, or at least in the portion where the contact slides. The fluorinated lubricant in the lubricating layer has carboxyl or isocyanate groups at its ends, which form hydrogen bonds with the resistive element, resulting in a strong and tight bond.

[0006] Existing technical documents Patent documents Patent Document 1: Japanese Patent Application Publication No. 2001-230104 Summary of the Invention

[0007] The problem that the invention aims to solve However, for variable resistors that use fluorine-based lubricants as the lubricating layer for the carbon resistive body and the conductive brush, it is sometimes impossible to achieve the increased number of operating cycles brought about by the increasingly stringent requirements for long sliding life in recent years.

[0008] The purpose of this invention is to provide a variable resistor that achieves an increase in the number of operating cycles due to a longer sliding life.

[0009] Methods for solving problems As a means of solving the above-mentioned problems, the present invention has the following configuration.

[0010] A variable resistor is characterized in that it comprises a substrate, a resistive body containing carbon powder and an adhesive resin for solidifying the carbon powder and applied to the surface of the substrate, a conductive brush sliding on the surface of the resistive body, and a lubricant coated on the surface of the resistive body. The lubricant is a molecular structure having polar functional groups at one end and the other end of a chain structure containing covalent bonds of multiple carbon atoms, and having a greater number of hydrogen atoms bonded to the multiple carbon atoms than the number of fluorine atoms bonded to the multiple carbon atoms.

[0011] The surface of the wear powder generated by the repeated sliding of the conductive brush on the surface of the resistive element is composed of carbon (C), hydrogen (H), and oxygen (O). Therefore, the lubricant in the variable resistor of the present invention has a molecular structure in which the number of hydrogen atoms bonded to the multiple carbon atoms forming the chain structure is greater than the number of fluorine atoms bonded to the multiple carbon atoms. Compared with conventionally used fluorine-based lubricants that have fluorine bonded to the multiple carbon atoms forming the chain structure, the lubricant with such a molecular structure exhibits better wettability with the wear powder. Therefore, the wear powder is easily and uniformly dispersed in the lubricant, and even in the case of wear powder generated by repeated use, agglomeration and thickening of the wear powder can be suppressed. Thus, the thickening and agglomeration of wear powder generated by the sliding of the conductive brush on the surface of the resistive element can be suppressed.

[0012] The aforementioned polar functional group can also be a hydroxyl group.

[0013] The chain structure described above may also have oxygen atoms in the middle portion, in addition to the polar functional groups at one and the other ends.

[0014] By setting the polar functional group to hydroxyl and having an oxygen atom in the middle part of the chain structure, the wettability of the lubricant relative to the resistive body is improved.

[0015] The aforementioned lubricant may also be a polyalkylene glycol or a bonded mixture of multiple polyalkylene glycols.

[0016] The above-mentioned lubricant can also be polybutanediol.

[0017] The above-mentioned lubricant can also be a polyalkylene glycol-glycerol ether.

[0018] The above-mentioned lubricant can also be polypropylene glycol-glycerol ether.

[0019] By utilizing the aforementioned lubricant, which exhibits excellent wettability with respect to the resistive element, noise caused by wear powder resulting from the sliding of the conductive brush can be suppressed.

[0020] The aforementioned adhesive resins may also have hydroxyl groups.

[0021] The adhesive resin mentioned above can also be a phenolic resin.

[0022] By using adhesive resins containing hydroxyl groups, such as phenolic resins, it is possible to suppress the noise caused by wear powder generated from the sliding of conductive brushes.

[0023] Invention Effects The variable resistor of the present invention, by using a lubricating oil having a molecular structure in which the number of hydrogen atoms bonded to carbon atoms is greater than the number of fluorine atoms bonded to carbon atoms, can suppress the thickening and agglomeration of wear powder in the resistive element. Therefore, a variable resistor can be provided that, when a conductive brush repeatedly slides across the surface of the resistive element, suppresses the generation of noise caused by wear powder and increases the number of operating cycles through a longer sliding life. Attached Figure Description

[0024] Figure 1 This is a plan view schematically illustrating the essential parts of a variable resistor according to an embodiment of the present invention.

[0025] Figure 2 It is a schematic representation Figure 1 A diagram of the cross-section at line AA.

[0026] Figure 3 This is a schematic diagram showing the cross-section of a variable resistor in a reusable state.

[0027] Figure 4 This is a substitute photograph of the conductive brush surface in a previous variable resistor that caused problems during operation.

[0028] Figure 5 This is a schematic diagram illustrating the cross-section of a variable resistor according to an embodiment of the present invention in a repeatedly used state.

[0029] Figure 6 The accompanying photograph is a substitute photograph showing the state of Reference Example 3 (fluorine-based lubricant) containing 40% by weight of wear powder.

[0030] Figure 7 The accompanying photograph is a substitute photograph showing the state of Reference Example 4 (the lubricant of the present invention) containing 40% by weight of wear powder.

[0031] Figure 8 It is a graph showing the change in output voltage and noise level over time when there are no problems.

[0032] Figure 9 It is a graph showing the change in output voltage and noise level over time when a problem has occurred.

[0033] Figure 10It is a graph showing the change in output noise as the number of slides increases.

[0034] Explanation of symbols 1. Variable resistor 2 substrate 3 Resistor 4. Conductive brush 5. Lubricant 6 terminals 7 terminals 101 Variable Resistor 105 Fluorine-based lubricants L length Detailed Implementation

[0035] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. The same symbols will be used to label the same components in each drawing, and descriptions will be omitted where appropriate. Reference coordinates will be appropriately shown in each drawing to indicate the positional relationships of the components. The X, Y, and Z directions in the reference coordinates are mutually orthogonal.

[0036] Figure 1 This is a plan view schematically showing the main parts of the variable resistor 1 involved in this embodiment.

[0037] The variable resistor 1 includes a substrate 2, a resistor 3, a conductive brush 4 that slides on the surface of the resistor 3, and a lubricant 5 coated on the surface of the resistor 3.

[0038] The variable resistor 1 includes a substrate 2 on which a resistive element 3 is disposed, and a conductive brush 4, which is a sliding member that moves (slides) on the resistive element 3 while maintaining contact with its surface. As the conductive brush 4 slides on the resistive element 3 containing the conductive element, the relative position of the conductive brush 4 within the resistive element 3 changes, thereby changing the length L of the portion of the resistive element 3 in which electrical current flows. Corresponding to the length L of the portion of the resistive element 3 in which electrical current flows, the resistance value of the circuit connected to the terminal 6 of the resistive element 3 and the terminal 7 of the conductive brush 4 changes. Therefore, the variable resistor 1 can, for example, detect the position of an analog joystick linked to the conductive brush 4 based on the voltage change corresponding to the resistance value.

[0039] The substrate 2 is a component on which the resistor 3 is formed. It is mainly composed of insulating molded bodies such as phenol laminate substrate, glass-added epoxy substrate, molded resin substrate, and ceramic substrate.

[0040] The resistor 3 comprises carbon powder as the main component and a binder resin for binding the carbon powder, and is deposited on the substrate 2. Typically, it is formed using a resistor paste, which disperses a conductive carbon powder such as carbon black in a binder resin dissolved in a suitable solvent, and further adds solvent as needed. The resistor 3 is manufactured by forming a pattern of a predetermined shape on the surface of the substrate 2 using a known method such as screen printing. During the formation of the resistor 3, it may also be dried to remove the solvent and then fired, as needed.

[0041] Phenolic resin or polyimide resin is used as the binder resin in the resistive paste. Using phenolic resin or polyimide resin imparts heat resistance to the resistive element 3. Furthermore, by using resins with hydroxyl groups, such as phenolic resin, as the binder resin, the wettability of the lubricant 5, which has polar functional groups such as hydroxyl groups, is improved, making it easier and more uniformly spread on the resistive element 3. In order to impart wear resistance, fillers such as carbon fiber and silica, as well as additives such as defoamers, may also be added to the resistive paste.

[0042] like Figure 1 As shown, when the resistor 3 is formed into an elongated shape, it is slidably mounted relative to the substrate 2 such that the conductive brush 4 slides along the resistor 3, thus becoming a sliding variable resistor 1. The shape of the resistor 3 is not limited to an elongated shape; for example, it can also be formed into an arc shape (horseshoe shape). In this case, it is rotatably mounted relative to the substrate 2 such that the conductive brush 4 slides along the resistor 3, thus becoming a rotary variable resistor 1.

[0043] Terminal 6 is provided, for example, by screen printing a conductive paste such as silver onto the substrate 2 before the resistor 3 is provided. Then, the pattern of the resistor 3 is provided so as to cover the top of the terminal 6, and the terminal 6 is electrically connected to the resistor 3.

[0044] The conductive brush 4 is made of a noble metal material that maintains good contact with the resistive element 3 when repeatedly sliding on its surface for extended periods. Specifically, materials obtained by plating phosphor bronze (copper-zinc-nickel alloy) with gold or silver, or alloys of palladium, silver, platinum, or nickel can be used. Especially when there is concern about surface oxidation at high temperatures, noble metal alloys are preferred to maintain a stable contact state.

[0045] Figure 2 It is a schematic representation Figure 1The figure shows a cross-section at line AA of the variable resistor 1. As shown in the figure, to improve the wear resistance of the surface of the resistor 3, a lubricant 5 is coated on the surface of the resistor 3 on the substrate 2. Conventionally, a fluorine-based lubricant has been used as the lubricant 5. Here, a fluorine-based lubricant refers to a substance that is fluid at room temperature (25°C) and in which more than half of the atoms bonded to the multiple carbon atoms constituting the main chain are fluorine.

[0046] Figure 3 This is a schematic diagram showing a cross-section of a conventional variable resistor 101 in a repeatedly used state.

[0047] Figure 4 This is a substitute photograph of the surface of the conductive brush 4 in the conventional variable resistor 101, which caused problems during operation.

[0048] like Figure 3 As shown, due to repeated use, the conductive brush 4 wears down as it slides on the surface of the resistor 3, mainly producing wear powder from the resistor 3. This wear powder mixes with the fluorine-based lubricant 105.

[0049] The main component of the wear powder is the carbon powder contained in the resistor 3. Because it has low affinity for the fluorinated lubricant 105, it thickens by mixing with the fluorinated lubricant 105, producing a semi-solid insulating material. Furthermore, as... Figure 4 As shown, the thickened insulating material is held between the sliding contact of the conductive brush 4 and the resistor 3, which causes output noise during the sliding of the conductive brush 4. Therefore, it is known that it is difficult to achieve a long sliding life for conventional variable resistors 101 that use fluorine-based lubricant 105.

[0050] Therefore, in order to achieve a long sliding life, the variable resistor 1 in this embodiment uses a lubricant 5 instead of a fluorine-based lubricant 105. The lubricant 5 has a molecular structure that is easy to mix with the wear powder of the resistor 3 and does not easily produce thickened insulating material.

[0051] Figure 5 It indicates a state of repeated use. Figure 1 A schematic diagram of the cross-section of the variable resistor 1 at line AA. By using a lubricant 5 that is well integrated with the wear powder of the resistor 3, the wear powder generated by the repeated sliding of the conductive brush 4 on the surface of the resistor 3 can be dispersed in the lubricant 5.

[0052] That is, the lubricant 5 has a molecular structure in which polar functional groups are present at one end of a chain structure containing multiple carbon atoms in covalent bonds, and the number of hydrogen atoms bonded to the multiple carbon atoms is greater than the number of fluorine atoms bonded to the multiple carbon atoms. Therefore, compared with conventional fluorine-based lubricants 105, which have a greater number of fluorine atoms bonded to the multiple carbon atoms than hydrogen atoms, it integrates well with the wear powder of the resistor 3 and is less likely to produce thickened insulating material. Therefore, the output noise caused by the thickened insulating material being held by the sliding contact between the conductive brush 4 and the resistor 3 can be suppressed, and the sliding life of the variable resistor 1 can be extended.

[0053] When the resistor 3 comprises carbon powder and phenolic resin, the surface of the resistor 3 is composed of carbon atoms (C), hydrogen atoms (H), and oxygen atoms (O). Therefore, by using a lubricant 5 composed of carbon atoms (C), hydrogen atoms (H), and oxygen atoms (O) with polar functional groups such as hydroxyl and carboxyl groups at one end and the other end of the chain structure, the affinity with the resistor 3 and the wear powder of the resistor 3 is improved. Therefore, from the viewpoint of affinity with the wear powder, the lubricant 5 is more preferably free of fluorine atoms.

[0054] Furthermore, the chain structure of lubricant 5 preferably has oxygen atoms in the middle portion, excluding the polar functional groups at one and the other ends. By having oxygen atoms in the middle portion of the chain structure, the affinity of lubricant 5 for resistive body 3 is further improved.

[0055] By using a lubricant 5 composed of the same elements (C, H, O) as the resistor 3, and having hydroxyl groups at one and the other ends of the chain structure that easily adsorb onto the wear powder of the resistor 3, the wear powder becomes easier to wet in the lubricant 5, thus improving the dispersibility of the wear powder relative to the lubricant 5. Therefore, thickening of the lubricant 5 caused by the wear powder can be suppressed, and the lubricant 5 becomes easier to maintain its fluidity. As a result, the formation of thickened insulation material due to repeated sliding of the conductive brush 4 on the surface of the resistor 3 can be suppressed. Furthermore, even if insulation material is formed, it is easily pushed away by the conductive brush 4 because of the good affinity between the lubricant 5 contained in the insulation material and the wear powder. Therefore, it becomes difficult for insulation material to be trapped between the resistor 3 and the conductive brush 4, and the contact at the contact point is stable. Consequently, the wear powder of the resistor does not agglomerate or thicken, suppressing the generation of output noise when the conductive brush 4 slides on the surface of the resistor 3, and enabling a longer sliding life of the variable resistor 1.

[0056] Examples of lubricants 5 include polyalkylene glycols, composites of various polyalkylene glycols, composites of various polyalkylene glycols and alkylene groups, polyalkylene glycol-glycerol ethers with polyalkylene glycols bonded to each of the three ends of glycerol, and polyalkylene glycol-sorbitol ethers. Examples of polyalkylene glycols include polyethylene glycol, polypropylene glycol, and polybutanediol. Examples of composites of various polyalkylene glycols include polyethylene glycol-polypropylene glycol-block ethers, polyethylene glycol-polybutanediol-block ethers, and polypropylene glycol-polybutanediol-block ethers. Polybutanediol and polypropylene glycol-glycerol ethers are preferred among these.

[0057] From the viewpoint of extending the sliding life of the variable resistor 1, the molecular weight (weight-average molecular weight) of the lubricant 5 is preferably 300 to 3000, more preferably 500 to 2000, and even more preferably 600 to 1800.

[0058] From the viewpoint of improving the affinity with the resistive body 3, the number of hydroxyl groups per 1000 molecular weight of the lubricant 5 is preferably 2 or more and about 4 or less.

[0059] From the viewpoint of extending the sliding life of the variable resistor 1, the kinematic viscosity of the lubricant 5 at 45°C is preferably around 30 to 70 centistokes (cst).

[0060] From the viewpoint of stability under low temperature conditions, the flow point of lubricant 5 is preferably below 0°C, more preferably below -10°C, and even more preferably below -20°C.

[0061] Commercially available products that can be used as lubricants include UNIOL (registered trademark) PB series, UNIOL (registered trademark) TG series, UNIOL (registered trademark) HS series, PLOON (registered trademark) series, UNIOX (registered trademark) series, and UNIOX (registered trademark) ST series manufactured by Nippon Oil Co., Ltd.

[0062] From the viewpoint of ensuring the lubricant 5 functions properly and preventing performance degradation of the variable resistor 1, the film thickness of the lubricant 5, which is formed in layers on the resistive body 3, is preferably 0.07 μm or more, more preferably 0.2 μm or more, and even more preferably 0.8 μm or more. From the viewpoint of maintaining stable contact between the resistive body 3 and the conductive brush 4, it is preferably set to 3 μm or less.

[0063] In lubricant 5, other lubricants and additives may also be mixed as needed, but in the materials constituting lubricant 5, polyalkylene glycol and / or polyalkylene glycol-glycerol ether is preferably 80% by weight or more, more preferably 100% by weight.

[0064] Example (A mixture of abrasive powder and lubricating oil) After sintering a resistor paste containing carbon powder and phenolic resin to form a solid, the solid was then pulverized and micronized using an automatic mortar machine for 100 hours. This process produced micronized resistor 3 particles with a diameter of less than 1 μm, equivalent to the wear powder generated when the conductive brush 4 slides on the surface of the resistor 3. This micronized powder was then mixed with lubricant 5 using an automatic mortar machine for 30 minutes to produce a suspected thickened wear powder, equivalent to the wear powder of the resistor 3 mixed with lubricant 5 generated by the sliding of the conductive brush 4 on the surface of the resistor 3. The state of this powder was then evaluated.

[0065] As a previous fluorinated lubricant 105 (refer to...) Figure 3 Using a FOMBLIN (registered trademark) ZDOL2000 with the following structural formula, a suspected thickening abrasive powder was prepared by setting the micro powder of resistivity 3 at 17 wt%, 24 wt%, and 40 wt%, and the viscosity was evaluated using a rotational viscometer. The results are shown in Table 1 (viscometer rotation speed 100 rpm).

[0066] ZDOL2000 (2 hydroxyl groups, weight-average molecular weight 2000, kinematic viscosity 28.7 cst (40°C), pour point -40°C, 1 hydroxyl group per 1000 molecular weight, FOMBLIN (registered trademark) ZDOL2000) [Chemical Formula 1] (m and n are integers.) As shown in Table 1, when using fluorine-based lubricants, at a low concentration of approximately 24% by weight of the micronized powder, the suspected thickened wear powder becomes slippery. However, at a high concentration of 40% by weight of the micronized powder, such as... Figure 6 As shown, the mixture becomes so dry that the viscosity of the suspected thickened abrasive powder cannot be determined. This state can be said to reflect the state of the lubricant and abrasive powder mixture in variable resistor 1, which becomes a source of output noise (see reference). Figure 4 ).

[0067] Therefore, instead of fluorine-based lubricants, the following lubricant was used to prepare a suspected thickened wear powder with a micronized powder concentration of 40% by weight, and the viscosity was evaluated under the same conditions. The results are shown in Table 2.

[0068] ·PB700 (Polybutanediol, weight average molecular weight 700, hydroxyl groups at both ends, kinematic viscosity 40-65 cst (40°C), pour point -40°C, number of hydroxyl groups per 1000 molecular weight 2.86, UNIOL (registered trademark) PB-700, manufactured by Nippon Oil Co., Ltd.) [Chemical Formula 2] (a and b are integers, a + b = 9) ·TG1000R (polypropylene glycol-glycerol ether, glycerol-like structure, weight-average molecular weight 1,000, kinematic viscosity 200-300 cst (25°C), pour point -25°C, number of hydroxyl groups per 1000 molecular weight 3, UNIOL (registered trademark) TG-1000R, manufactured by Nippon Oil Co., Ltd.) [Chemical Formula 3] (a, b, and c are integers, and a + b + c = 16) • MB7 (Polyalkylene glycol derivative (non-water-soluble type), hydroxyl-terminated, weight-average molecular weight 700, kinematic viscosity 32.8 cst (40°C), pour point -47.5°C, number of hydroxyl groups per 1000 molecular weight 1.43, UNILUBE (registered trademark) MB-7, manufactured by Nippon Oil Co., Ltd.) [Chemical Formula 4] • MB11 (Polyalkylene glycol derivative (non-water-soluble type), hydroxyl-terminated, weight-average molecular weight 1,000, kinematic viscosity 56.1 cst (40°C), pour point -42.5°C, number of hydroxyl groups per 1,000 molecular weight 1, UNILUBE (registered trademark) MB-11, manufactured by Nippon Oil Co., Ltd.) [Chemical Formula 5] None of the suspected thickening abrasive powders had the dry, brittle texture of Reference Example 3. Figure 7Reference Example 4 shown also exhibits a slippery texture. The suspected thickened abrasive powders of Reference Examples 4-7 all have measurable viscosity. This result demonstrates the possibility that by using a lubricant with good affinity for the abrasive powder found in Reference Examples 4-7, which reproduces a mixture containing abrasive powder generated by sliding, the generation of an insulator containing both abrasive powder and lubricant, which contributes to output noise, can be suppressed. From the viewpoint of suppressing the generation of an insulator containing both abrasive powder and lubricant, it is preferable to use a lubricant with a viscosity of 4,000 CPS (mPa·s) or less at 100 rpm obtained by mixing the resistive micropowder with the lubricant in such a manner that the micropowder of the resistivity is 40% by weight.

[0069] (Determination of sliding life) For the variable resistor 1 using the lubricants of Reference Examples 3 to 6, the sliding life was measured by reciprocating the conductive brush 4 along the X direction on the surface of the resistor body 3 (see Reference Examples 3 to 6). Figure 1 In this measurement, a resistor 3 with a total resistance of 5kΩ was used, and the load on the conductive brush 4 was set to 7g / brush.

[0070] Figure 8 The graph shows the output voltage and noise level of the variable resistor 1 with its conductive brush 4 making two round trips over time, in a state where there are no problems.

[0071] Figure 9 The graph shows the output voltage and noise level of the variable resistor 1 with two round trips of the conductive brush 4 as the problem condition is shown over time.

[0072] At the moment the sliding life test begins, the output voltage from variable resistor 1 is as follows: Figure 8 The changes proceeded smoothly as shown. However, as the sliding life test was conducted, a mixture of lubricant 5 and wear powder was generated, and the output voltage from the variable resistor 1 produced... Figure 9 The variable resistor 1 has a sawtooth-shaped portion as shown in the diagram. If the difference between the output voltage in this sawtooth-shaped portion and the smoothly changing output voltage, i.e., the noise level, exceeds a specified threshold, an adverse condition occurs in the operation of the controller using the variable resistor 1. The sliding life of the variable resistor 1 is evaluated by the number of times the output voltage from the variable resistor 1 produces output noise exceeding the threshold. The measurement results are shown in Table 3.

[0073] Figure 10 This is a graph showing the change in output noise with increasing sliding number for Examples 1, 2, and Comparative Example 1. It should be noted that... Figure 10In the graphs, for Example 1 and Comparative Example 1, the variation in the output noise level of the sample that yielded the best results is shown.

[0074] As shown in Table 3 and Figure 10 As shown, the variable resistors 1 of Examples 1 and 2, compared with the variable resistor 1 of Comparative Example 1 which uses a fluorine-based lubricant, have an increased number of sliding cycles until the noise level of the output voltage reaches a threshold, thus achieving a longer sliding life.

[0075] Regarding the variable resistors 1 in Comparative Examples 2 and 3, although a lubricant composed of carbon atoms (C), hydrogen atoms (H), and oxygen atoms (O) was used instead of a fluorine-based lubricant, the same long sliding life as in Examples 1 and 2 could not be achieved, as shown in Table 3. Comparative Example 2 had 1.43 hydroxyl groups per 1000 molecular weights, and Comparative Example 3 had 1 hydroxyl group per 1000 molecular weights, a smaller proportion of hydroxyl groups compared to Examples 1 and 2. Furthermore, Examples 1 and 2 had polar functional groups at both ends of the chain structure, while Comparative Examples 2 and 3 differed in that they only had polar functional groups at one end of the chain structure. Based on these results, it is concluded that the number of hydroxyl groups per 1000 molecular weights and the presence or absence of polar functional groups at the ends of the chain structure are also related to the long sliding life of the variable resistor 1. From the viewpoint of achieving a long sliding life of the variable resistor 1, the number of hydroxyl groups per 1000 molecular weights is preferably 1.5 or more, more preferably 2.0 or more. Furthermore, it can be said that lubricants with hydroxyl groups as polar functional groups at one end and the other end of the chain structure are preferred.

[0076] The embodiments disclosed in this specification are illustrative in all respects and are not intended to limit the scope of the invention. The scope of the invention is not indicated by the description of the embodiments described above, but by the claims, and it is intended that all modifications contained within the claims and their equivalents be included within the scope of the invention.

[0077] Industrial availability This invention can be used as a variable resistor in controllers of gaming devices, etc.

Claims

1. A variable resistor, characterized in that, This variable resistor has the following features: substrate; A resistor comprising carbon powder and an adhesive resin for solidifying the carbon powder and applied to the surface of the substrate; A conductive brush that slides on the surface of the resistive element; and Lubricant applied to the surface of the resistor. The lubricant is a molecular structure having polar functional groups at one end and the other end of a chain structure containing multiple carbon atoms in which the number of hydrogen atoms bonded to the multiple carbon atoms is greater than the number of fluorine atoms bonded to the multiple carbon atoms.

2. The variable resistor according to claim 1, wherein, The polar functional group is a hydroxyl group.

3. The variable resistor according to claim 1, wherein, The chain structure has oxygen atoms in the middle portion, except for the polar functional groups at one and the other ends.

4. The variable resistor according to claim 1, wherein, The lubricant is a polyalkylene glycol or a bonded mixture of multiple polyalkylene glycols.

5. The variable resistor according to claim 1, wherein, The lubricant is polybutanediol.

6. The variable resistor according to claim 1, wherein, The lubricant is a polyalkylene glycol-glycerol ether.

7. The variable resistor according to claim 1, wherein, The lubricant is polypropylene glycol-glycerol ether.

8. The variable resistor according to claim 1, wherein, The adhesive resin has hydroxyl groups.

9. The variable resistor according to claim 8, wherein, The adhesive resin is a phenolic resin.

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