Potentiometer with low contact resistance

Abstract

The utility model discloses a potentiometer with low contact resistance, which belongs to the technical field of electrical components and aims to solve the problem that the use of a potentiometer resistor disc in the prior art is influenced due to large contact resistance. The device comprises a substrate and a conductive brush assembly, an annular copper wire is laid on the substrate, two conductive sheets are arranged on the substrate and located on the two sides of the annular copper wire, a resistor disc is communicated between the two conductive sheets, and the resistor disc is composed of an eight-time high-resistance carbon film layer, a silver layer and a high-resistance carbon film layer from bottom to top. The substrate is also provided with a wiring terminal used for connecting the circular ring copper wire and the two conductive sheets, and the conductive brush assembly is used for connecting the circular ring copper wire and the resistor sheets; according to the utility model, the contact resistance of the resistor disc in the potentiometer can be improved, the contact resistance of the resistor disc used for assembling the potentiometer can be controlled within 2%, and meanwhile, the smoothness of a resistance curve is ensured without abrupt change.

Description

Technical Field

[0001] This utility model relates to a potentiometer with low contact resistance, belonging to the field of electrical component technology. Background Technology

[0002] With the development of electronic technology, the performance requirements for electronic components are becoming increasingly stringent. When potentiometers are used as control switches for dimming or speed regulation, general-performance products can no longer meet the requirements, mainly because of their high contact resistance. The contact resistance of a general-performance potentiometer is within 8% of its total resistance. When used as a control switch for dimming or speed regulation, problems such as insufficient brightness of the dimming switch or premature idling of the speed regulation switch may occur. This necessitates reducing the contact resistance of the potentiometer to meet the requirements of dimming or speed regulation. Therefore, improvements need to be made to the resistor elements used in potentiometer assembly.

[0003] The resistors currently used in potentiometer assembly are manufactured using a process of silver layer—4 times high-resistivity carbon film—high-resistivity carbon film—low-resistivity sulfurized carbon film. This manufacturing process has three problems: First, when sliding from the high-resistivity carbon film to the low-resistivity high-resistivity sulfurized carbon film, there will be a sudden change in resistance, resulting in an uneven output resistance curve. Second, actual tests show that the contact resistance on the low-resistivity high-resistivity sulfurized carbon film is within 2%, while the contact resistance on the high-resistivity carbon film is within 5%, which is still considered too high. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a potentiometer with low contact resistance, which improves the contact resistance of the resistor element in the potentiometer. It can control the contact resistance of the resistor element used in potentiometer assembly to within 2%, while ensuring the smoothness of the resistance curve without abrupt changes.

[0005] To achieve the above objectives, this utility model employs the following technical solution:

[0006] A low contact resistance potentiometer includes a substrate and a conductive brush assembly. A circular copper wire is disposed on the substrate, and two conductive plates are disposed on the substrate on both sides of the circular copper wire. A resistive plate is connected between the two conductive plates. The resistive plate is composed of an eight-layer high-resistivity carbon film, a silver layer, and a high-resistivity carbon film from bottom to top. The substrate is also provided with terminals for connecting the circular copper wire and the two conductive plates. The conductive brush assembly is used to connect the circular copper wire and the resistive plate.

[0007] Specifically, the substrate is provided with a cover for covering the resistor sheet, an annular sealing layer is provided between the cover and the substrate, and the bottom of the cover has an annular pressing surface that presses against the annular sealing layer.

[0008] Specifically, the upper surface of the substrate is provided with a U-shaped opening, the annular sealing layer is provided at the top surface of the U-shaped opening, the electrical wires of the terminal pass through the bottom of the U-shaped opening, and sealing rings for sealing the electrical wires are provided at both ends of the U-shaped opening.

[0009] Specifically, the top of the cover is provided with an air inlet, and a sealing sheet is provided at the location of the air inlet of the cover.

[0010] Specifically, the cross-section of the air inlet is a circle with two overlapping parts.

[0011] Specifically, the conductive brush includes a guide sleeve rotatably disposed at the center of the substrate, a T-shaped rod slidably disposed on the guide sleeve, a spring abutting against the guide sleeve at the bottom end of the T-shaped rod, a connecting rod mounted at the top end of the T-shaped rod, and a contact piece for contacting the resistive element and the circular copper wire on the connecting rod.

[0012] Specifically, the contact piece is provided with a flexible abutment rod, which is used to abut the contact piece against the resistive sheet.

[0013] Specifically, the guide sleeve is integrally provided with a drive tube and a positioning disk disposed on the outer ring of the drive tube. A damping adjustment screw is threadedly connected to the positioning disk. An annular damping track is disposed below the base plate. The damping adjustment screw acts on the annular damping track.

[0014] Compared with the prior art, the beneficial effects achieved by this utility model are as follows:

[0015] This invention adjusts the layering and design of the potentiometer resistor sheet, placing the high-resistance carbon film layer before the silver layer. This reduces the height difference at the carbon-silver junction, improves the interface contact quality, and ensures that the current passes through the area with the same sheet resistance when the metal brush rotates, thus mitigating the problem of abrupt changes in the resistance curve. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the overall structure of the potentiometer provided in this embodiment of the utility model;

[0017] Figure 2 This is a partial structural diagram of the potentiometer cover provided in an embodiment of the present invention;

[0018] Figure 3 This is a partial structural schematic diagram of the potentiometer provided in an embodiment of the present invention;

[0019] Figure 4 This is a front view of the potentiometer provided in an embodiment of this utility model;

[0020] Figure 5 This is a utility model Figure 4 A cross-sectional view of the potentiometer along the AA direction provided in the embodiment;

[0021] Figure 6 This is a utility model Figure 4 A cross-sectional view of the potentiometer along the BB direction provided in the embodiment;

[0022] Reference numerals: 1. Substrate; 2. Circular copper wire; 3. Resistor; 4. Terminal; 5. Cover; 6. Annular sealing layer; 7. U-shaped opening; 8. Air inlet; 9. Sealing plate; 10. Guide sleeve; 11. T-shaped rod; 12. Spring; 13. Connecting rod; 14. Contact piece; 15. Drive tube; 16. Positioning disc; 17. Damping adjustment screw; 18. Annular damping track; 19. Flexible abutment rod. Detailed Implementation

[0023] The present invention will be further described below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and should not be used to limit the scope of protection of the present invention.

[0024] In the description of this utility model, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings and are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this utility model, unless otherwise stated, "a plurality of" means two or more.

[0025] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances. Example:

[0026] This utility model provides a low-contact-resistance potentiometer, used to improve the contact resistance of the resistive element in the potentiometer. It can control the contact resistance of the resistive element used in potentiometer assembly to within 2%, while ensuring the smoothness of the resistance curve without abrupt changes. To achieve the structural function of the potentiometer, it is configured to include a substrate 1 and a conductive brush assembly. Specifically, a circular copper wire 2 is laid on the substrate 1, and as shown... Figure 3As shown, two conductive sheets are disposed on the substrate 1 on both sides of the circular copper wire 2, and a resistive sheet 3 is connected between the two conductive sheets, thus realizing the basic structure of the potentiometer. In order to improve the contact resistance of the potentiometer, the resistive sheet 3 is composed of an eight-layer high-resistivity carbon film, a silver layer, and another high-resistivity carbon film from bottom to top. Since the sheet resistance of the high-resistivity carbon film is an important indicator of its resistance value, the greater the thickness, the higher the resistance. With the increase of the thickness of the first high-resistivity carbon film, the current needs to flow through a thicker carbon film layer, thereby effectively reducing the sheet resistance of the second high-resistivity carbon film. This can optimize the overall resistance distribution to a certain extent, avoiding uneven current flow or locally low resistance caused by an excessively thin second high-resistivity carbon film, which would affect the stability of the overall resistance. In other words, increasing the thickness of the first carbon film helps to better control the way the current flows through the resistive layer, making the overall resistance curve smoother and avoiding abrupt resistance changes caused by an excessively thin carbon film layer. The ultimate effect is improved resistor stability and uniformity, reduced drastic changes in the current path, and by placing the high-resistivity carbon film layer before the silver layer, the height difference at the carbon-silver interface is reduced, improving interface contact quality. This is because the interface between the carbon film and the metallic silver layer is often a critical area affecting current flow and contact resistance. If the silver layer is placed before the high-resistivity carbon film, it may cause a significant height difference or poor contact between the carbon film and the silver layer, resulting in higher contact resistance and thus affecting the overall stability and repeatability of the resistor. By placing the high-resistivity carbon film before the silver layer, the unevenness of this contact interface can be reduced, optimizing the contact quality between the two. This improves contact resistance, reduces interface noise, and ultimately enhances the overall performance stability of the resistor element 3. This not only improves the uniformity of current flow but also avoids resistance fluctuations caused by poor contact. Furthermore, during the rotation of the metal brush, uneven current flow across the resistive surface can lead to abrupt changes in resistance value. By covering the silver layer with a second high-resistivity carbon film, it ensures a more uniform resistance area when the metal brush contacts the carbon film, avoiding localized excessively high or low resistance variations. This ensures a stable current path, preventing abrupt changes in the resistance curve. The second high-resistivity carbon film covering the silver layer ensures consistent contact between the brush and the carbon film, reducing potential abrupt changes during resistor use. This effectively improves the adjustability and accuracy of the resistor, ensuring its stability and reliability, especially during rotating brushes or continuous current flow, reducing resistance instability caused by uneven contact. In order to enable the resistor to adjust its resistance normally, the substrate 1 is provided with terminals 4 for connecting the circular copper wire 2 and the two conductive plates, and a conductive brush assembly is provided for connecting the circular copper wire 2 and the resistive plate 3.

[0027] This utility model provides a low contact resistance potentiometer. In some embodiments, to prevent the oxidation of the circuit structure accelerated by moisture and oxygen in the environment and to improve the stability of the circuit environment, a cover 5 for covering the resistive element 3 can be provided on the substrate 1, and an annular sealing layer 6 is provided between the cover 5 and the substrate 1. The bottom of the cover 5 is ensured to have an annular pressing surface that presses against the annular sealing layer 6, thereby achieving complete sealing within the cavity and preventing premature oxidation of metal and other components. As a preferred embodiment, to further improve the sealing performance of the potentiometer, a U-shaped opening 7 is provided on the upper surface of the substrate 1, and the annular sealing layer 6 is positioned at the top surface of the U-shaped opening 7. Figure 5 As shown, the electrical wire of terminal 4 passes through the bottom of the U-shaped opening 7, thereby ensuring the smooth sealing of the annular sealing layer 6. In order to prevent gas from leaking out from the bottom of the U-shaped opening 7, sealing rings for sealing the electrical wire are provided at both ends of the U-shaped opening 7.

[0028] This utility model provides a low contact resistance potentiometer. To protect the components inside the sealed chamber, an inert gas can be filled into the chamber. For this purpose, an inflation port 8 can be directly provided on the top of the cover 5, and a sealing sheet 9 is provided at the inflation port 8 of the cover 5 to seal the inert gas. To facilitate the inflow and outflow of gas, considering the relatively small size of the potentiometer and the inconvenience of additional vent holes, the cross-section of the inflation port 8 can be designed as two overlapping circular parts. When one circular part is inflated, the other adjacent hole can allow gas to escape.

[0029] This utility model provides a potentiometer with low contact resistance. To improve the stability of the conductive connection, a conductive brush can be provided, including a guide sleeve 10 rotatably positioned at the center of the substrate 1. A T-shaped rod 11 is slidably disposed on the guide sleeve 10. Figure 5 As shown, the bottom end of the T-shaped rod 11 is provided with a spring 12 that abuts against the guide sleeve 10. At the same time, the top end of the T-shaped rod 11 is provided with a connecting rod 13, and a contact piece 14 for contacting the resistor 3 and the circular copper wire 2 is provided on the connecting rod 13. At this time, the spring 12 is used to push the connecting rod 13 downward, thereby driving the contact piece 14 to make stable contact with the resistor 3, which can prevent the influence of poor contact that may be caused by some vibration environment.

[0030] This utility model provides a potentiometer with low contact resistance, such as... Figure 6As shown, in order to further ensure stable contact between the contact 14 and the resistor 3, a flexible abutment rod 19 can be provided on the contact 14, such as a silicone rod. By setting the flexible abutment rod 19, the contact 14 is abutted against the resistor 3, thereby preventing poor contact caused by deformation of the resistor 3 under pressure. In other words, the abutment rod 19 can be used to ensure a certain support stability of the resistor 3, thereby stabilizing the contact effect.

[0031] This utility model provides a low contact resistance potentiometer. To improve the stability of the brush position, a drive tube 15 and a positioning disk 16 disposed on the outer ring of the drive tube 15 can be integrally provided on the guide sleeve 10. Figure 4 , Figure 5 as well as Figure 6 As shown, a damping adjustment screw 17 is threaded onto the positioning disc 16, and an annular damping track 18 is provided below the base plate 1. The damping adjustment screw 17 acts on the annular damping track 18. By adjusting the depth of the damping adjustment screw 17, the friction of the guide sleeve 10 is controlled, preventing minor accidental contact from causing it to slip and affecting normal use.

[0032] The above description is only a preferred embodiment of the present utility model. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present utility model, and these improvements and modifications should also be considered within the protection scope of the present utility model.

Claims

1. A potentiometer with low contact resistance, characterized in that, The assembly includes a substrate (1) and a conductive brush assembly. A circular copper wire (2) is laid on the substrate (1). Two conductive sheets are provided on the substrate (1) and on both sides of the circular copper wire (2). A resistor (3) is connected between the two conductive sheets. The resistor (3) is composed of an eight-fold high-resistivity carbon film layer, a silver layer and a high-resistivity carbon film layer from bottom to top. The substrate (1) is also provided with terminals (4) for connecting the circular copper wire (2) and the two conductive sheets. The conductive brush assembly is used to connect the circular copper wire (2) and the resistor (3).

2. A potentiometer with low contact resistance according to claim 1, characterized in that, The substrate (1) is provided with a cover (5) for covering the resistor sheet (3), and an annular sealing layer (6) is provided between the cover (5) and the substrate (1). The bottom of the cover (5) has an annular pressing surface that presses against the annular sealing layer (6).

3. A potentiometer with low contact resistance according to claim 2, characterized in that, The substrate (1) has a U-shaped opening (7) on its upper surface. The annular sealing layer (6) is located at the top of the U-shaped opening (7). The electrical wire of the terminal (4) passes through the bottom of the U-shaped opening (7). The openings at both ends of the U-shaped opening (7) are provided with sealing rings for sealing the electrical wire.

4. A potentiometer with low contact resistance according to claim 2, characterized in that, The top of the cover (5) is provided with an air inlet (8), and a sealing sheet (9) is provided at the air inlet (8) of the cover (5).

5. A potentiometer with low contact resistance according to claim 4, characterized in that, The cross-section of the air inlet (8) is a circle with two overlapping parts.

6. A potentiometer with low contact resistance according to claim 1, characterized in that, The conductive brush includes a guide sleeve (10) rotatably disposed in the middle of the substrate (1), a T-shaped rod (11) is slidably disposed on the guide sleeve (10), a spring (12) is provided at the bottom end of the T-shaped rod (11) to abut against the guide sleeve (10), a connecting rod (13) is installed at the top end of the T-shaped rod (11), and a contact piece (14) for contacting the resistor (3) and the circular copper wire (2) is provided on the connecting rod (13).

7. A potentiometer with low contact resistance according to claim 6, characterized in that, The contact piece (14) is provided with a flexible abutment rod (19), which is used to abut the contact piece (14) against the resistor piece (3).

8. A potentiometer with low contact resistance according to claim 6, characterized in that, The guide sleeve (10) is integrally provided with a drive tube (15) and a positioning disc (16) disposed on the outer ring of the drive tube (15). A damping adjustment screw (17) is threadedly connected to the positioning disc (16). An annular damping track (18) is disposed below the base plate (1). The damping adjustment screw (17) acts on the annular damping track (18).

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