A method for manufacturing a resistor plate for a potentiometer and an ultra-miniature servo sensor

Abstract

This invention discloses an ultra-miniature servo sensor, comprising: a housing, including an outer shell and a bottom cover embedded at the bottom of the outer shell; a limiting ring and a first through hole corresponding to a rotating shaft are provided in the middle of the bottom cover; a resistor plate is fixed inside the housing, with a second through hole in the middle of the resistor plate; one side of the resistor plate has a resistor sheet and a conductive sheet corresponding to a brush, and the other side has a wiring conductive sheet; a rotating shaft is rotatably disposed inside the housing, with a brush fixing plate extending from the side of the rotating shaft. The upper end of the rotating shaft is attached to the inner wall of the outer shell through the brush fixing plate, and the lower end extends into the limiting ring and abuts against the bottom cover. Compared with the prior art, this invention has the following advantages: this servo sensor optimizes and improves the structure of the housing, resistor plate, and rotating shaft in the prior art, and also optimizes the processing technology of the resistor plate, successfully achieving further miniaturization of the servo sensor, providing a design scheme and processing technology for a servo sensor within 4mm.

Description

Technical Field

[0001] This invention relates to the field of servo sensor technology, and in particular to a method for manufacturing a resistor plate for a potentiometer and an ultra-miniature servo sensor. Background Technology

[0002] A potentiometer converts a mechanical angle signal into an electrical signal output. It typically consists of a resistive element and a rotatable brush. As the brush rotates left and right on the resistive strip, a resistance value or voltage, which is related to the displacement, is obtained at the output terminal, thus determining the rotation angle. Due to their stable performance, simple structure, and low cost, potentiometers are widely used as sensors in servo motors.

[0003] Currently, there is a lack of structural design solutions in existing technologies that can make potentiometers smaller than 4mm, preventing the miniaturization of potentiometers. Therefore, optimization and improvement of existing potentiometer mechanisms are needed to further miniaturize them. However, the resistance plate in existing potentiometers still faces the following problems in miniaturization production: 1. During the production process, it is difficult to accurately fix the resistance plate in place, making it impossible to precisely determine the effective angle of the potentiometer; 2. Because the connectors at both ends of the resistance plate in existing technologies have stepped surfaces, these surfaces cause changes in the thickness of the resistive coating, thus affecting the voltage signal output by the potentiometer. Therefore, the stepped surfaces can only be treated as ineffective angles, reducing the true effective angle of the potentiometer. Therefore, there is a need for a method for manufacturing the resistance plate for potentiometers and an ultra-miniature servo sensor to solve the above problems. Summary of the Invention

[0004] The purpose of this invention is to overcome the problems of the prior art and provide an ultra-miniature aerospace servo sensor.

[0005] To achieve the above objectives, the present invention adopts the following solution:

[0006] An ultra-miniature servo sensor, comprising:

[0007] The housing comprises an outer shell and a bottom cover embedded at the bottom of the outer shell. The bottom cover is interference-fitted with the inner wall of the outer shell. Since both the bottom cover and the outer shell are ultra-small components, they are not suitable for complex connection structures. A limiting ring and a first through hole corresponding to the rotating shaft are located in the middle of the bottom cover. After installation, the upper surface of the rotating shaft is flush with the upper surface of the outer shell. Inside the outer shell, from top to bottom, there are a rotating cavity for fixing the brush plate and a non-circular cavity for accommodating the resistor plate. The rotating cavity is circular, allowing the brush plate on the rotating shaft to rotate within it. The non-circular cavity restricts the rotation of the resistor plate within the housing. The housing is machined from aluminum alloy, a material easily machined and engraved. The outer shell also has integrally formed double ears on both sides, allowing it to be fixedly installed in the application equipment.

[0008] The resistor plate is fixed inside the housing and its shape corresponds to the shape of the receiving cavity. A second through hole is provided in the middle of the resistor plate so that the rotating shaft can pass through. One side of the resistor plate is provided with a resistor sheet and a conductive sheet corresponding to the brush, and the other side is provided with a wiring conductive sheet.

[0009] The rotating shaft is rotatably housed within the housing. A connecting hole is located in the center of the shaft, communicating with a through hole. A brush mounting plate extends from the side of the shaft for mounting the brush. This integrated design of the rotating shaft and brush mounting plate allows for further miniaturization of the sensor. The upper end of the brush mounting plate is in close contact with the inner wall of the upper part of the housing, while the lower end has a fixing post for securing the brush. The upper end of the rotating shaft fits against the inner wall of the housing via the brush mounting plate, while the lower end extends into a limiting ring and abuts against the bottom cover. Since the rotating shaft does not require an additional fixing structure from the housing, this design further reduces the height of the sensor.

[0010] Furthermore, the conductive sheet includes a first conductive sheet, a second conductive sheet, and a third conductive sheet. The first and second conductive sheets are respectively disposed at both ends of the resistor sheet, and the third conductive sheet is disposed on both sides of the second through hole. This layout design can disperse the wiring positions on the back of the resistor board, reducing the difficulty of wiring.

[0011] Furthermore, an insulating region is provided between the first conductive sheet, the second conductive sheet, and the third conductive sheet.

[0012] Furthermore, the brush is a C-type brush with a fixing hole in the middle corresponding to the fixing post. The brush is fixed to the lower side of the brush fixing plate through the fixing hole. Brush claws extend symmetrically on both sides of the brush and are respectively connected to the third conductive plate and the resistive plate. The single-turn working area design can further reduce the length and width of the sensor. The C-type brush allows the brush to be miniaturized while maintaining its strength.

[0013] Furthermore, the distance between the brush fixing plate and the resistor plate is 0.5-0.7mm. That is, the brush height is 0.5-0.7mm.

[0014] Furthermore, the limiting ring has slots to avoid the welding points. These slots are distributed on the limiting ring at a 120° angle to each other, and are spread out as much as possible to facilitate the welding operation because the limiting ring is extremely small.

[0015] Furthermore, the bottom cover is interference-fitted with the inner wall of the housing, while a gap is left between the bottom cover and the resistor plate. This prevents the bottom cover from contacting the resistor plate and affecting the working state of the sensor.

[0016] Furthermore, the outer diameter of the shell is 4mm, and the inner diameter of the rotating cavity is 3.6mm.

[0017] A method for manufacturing a resistor plate for a potentiometer includes the following steps:

[0018] S10 obtains a pre-defined shape by machining the resistive plate body;

[0019] The S20 exposure process combines a mask or photomask with the board body, subtracting the copper area on the board body except for the conductive sheet area, to obtain a highly accurate effective angle. The exposure process can accurately determine the conductive and resistive areas of the resistor board, which greatly improves the positional accuracy of the conductive sheet and then the resistor sheet in the ultra-micro resistor board compared with the existing process.

[0020] S30 applies an insulating layer to the working area of ​​the board; the insulating layer can eliminate the step surface at the junction of the carbon film and the conductive sheet, prevent the V-shaped brush claw from contacting the resistor sheet and the conductive sheet at the same time, and make the thickness of the resistor sheet uniform at both ends, eliminating the dummy position of the effective angle so that the true effective angle of the potentiometer is closer to the designed effective angle.

[0021] S40 forms a resistor by printing a carbon film on the insulating layer of the resistor area of ​​the board.

[0022] S50 has abrasion-resistant conductive paint printed on the conductive sheet.

[0023] An ultra-miniature servo sensor includes a housing, a rotating shaft, and a resistor plate disposed within the housing. The resistor plate is manufactured using the aforementioned method for producing a resistor plate for a potentiometer.

[0024] Compared with existing technologies, this invention has the following advantages: The servo sensor optimizes and improves the structure of the housing, resistor plate, and rotating shaft in existing technologies, and also optimizes the processing technology of the resistor plate, ensuring that its processing accuracy is not affected by size reduction. This successfully achieves further miniaturization of the servo sensor, providing a design scheme and processing technology for a servo sensor within 4mm. Attached Figure Description

[0025] The present application will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0026] Figure 1 This is an exploded structural diagram of an ultra-miniature servo sensor according to the present invention.

[0027] Figure 2 This is a cross-sectional structural diagram of an ultra-miniature servo sensor according to the present invention.

[0028] Figure 3 This is a schematic diagram of the structure of the resistor plate in an ultra-miniature servo sensor of the present invention.

[0029] Figure 4 This is a schematic diagram of the bottom cover structure of an ultra-miniature servo sensor according to the present invention. Detailed Implementation

[0030] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and are not intended to limit the scope of the invention.

[0031] like Figure 1-4 As shown, an ultra-miniature servo sensor includes:

[0032] Casing 1, such as Figure 1 and 4 As shown, the housing 1 includes an outer shell 101 and a bottom cover 102 embedded at the bottom of the outer shell 101. The bottom cover 102 is interference-fitted with the inner wall of the outer shell 101. Since both the bottom cover 102 and the outer shell 101 are ultra-small volume workpieces, they are not suitable for complex connection structures. The bottom cover 102 has a limiting ring 1021 and a first through hole 1022 corresponding to the rotating shaft 2 at the middle position. After the rotating shaft 2 is installed, its upper surface is flush with the upper surface of the outer shell 101. The outer shell 101 has, from top to bottom, a rotating cavity 1011 for the brush fixing plate 201 and a non-circular receiving cavity 1012 for accommodating the resistor plate 3. The rotating cavity 1011 is circular. The brush fixing plate 201 on the rotating shaft 2 can rotate in the rotating cavity 1011. The non-circular receiving cavity 1012 can restrict the rotation of the resistor plate 3 in the housing 1. The housing 1 is machined from aluminum alloy, which is easy to machine and engrave. The outer casing 101 is also provided with two integrally formed ears on both sides, and the outer casing 101 can be fixedly installed in the application device through the two ears.

[0033] Resistor plate 3, such as Figure 1 and 3 As shown, the resistor plate 3 is fixed inside the housing 1 and its shape corresponds to the shape of the receiving cavity 1012. The middle position of the resistor plate 3 is provided with a second through hole 301 through which the rotating shaft 2 can pass. One side of the resistor plate 3 is provided with a resistor piece 302 and a conductive piece corresponding to the brush 4, and the other side is provided with a wiring conductive piece 306.

[0034] Shaft 2, such as Figure 1 and 2 As shown, the rotating shaft 2 is rotatably mounted inside the housing 1. A connecting hole 203 is located in the middle of the rotating shaft 2, communicating with a through hole. A brush fixing plate 201 for mounting the brush 4 extends from the side of the rotating shaft 2. The integrated design of the rotating shaft 2 and the brush fixing plate 201 allows for further miniaturization of the sensor. The upper end of the brush fixing plate 201 is in close contact with the inner wall of the upper end of the housing 1, and the lower end has a fixing post 202 for fixing the brush 4. The upper end of the rotating shaft 2 is fitted against the inner wall of the housing 101 via the brush fixing plate 201, and the lower end extends into the limiting ring 1021, abutting against the bottom cover 102. The rotating shaft 2 does not require additional fixing structures provided by the housing 1; therefore, this structural design further reduces the height of the sensor.

[0035] Preferably, the conductive sheet includes a first conductive sheet 303, a second conductive sheet 304, and a third conductive sheet 305. The first conductive sheet 303 and the second conductive sheet 304 are respectively disposed at both ends of the resistor sheet 302, and the third conductive sheet 305 and the resistor sheet 302 are respectively disposed on both sides of the second through hole 301. This layout design can disperse the wiring positions on the back of the resistor plate 3, reducing the difficulty of wiring.

[0036] Preferably, an insulating region 307 is provided between the first conductive sheet 303, the second conductive sheet 304 and the third conductive sheet 305.

[0037] Preferred, such as Figure 1 As shown, the brush 4 is a C-type brush. A fixing hole corresponding to the fixing post 202 is provided in the middle of the brush 4. The brush 4 is fixed to the lower side of the brush fixing plate 201 through the fixing hole. Brush claws extend symmetrically from both sides of the brush 4, respectively connecting to the third conductive sheet 305 and the resistive sheet 302. The single-turn working area design further reduces the length and width of the sensor. The C-type brush 4 allows for miniaturization while maintaining its strength.

[0038] Preferably, the distance between the brush fixing plate and the resistor plate is 0.5-0.7mm. That is, the height of the brush 4 when it is working is 0.5-0.7mm.

[0039] Preferably, the limiting ring 1021 is provided with slots 1023 for avoiding the welding points. The slots 1023 are distributed on the limiting ring 1021 at a 120° angle in pairs. Since the limiting ring 1021 is extremely small, they are spread out as much as possible to facilitate the welding operation.

[0040] Preferably, the bottom cover 102 is interference-fitted with the inner wall of the outer casing 101, and a gap is left between the bottom cover 102 and the resistor plate 3. This prevents the bottom cover 102 from contacting the resistor plate 3 and affecting the working state of the sensor.

[0041] Preferably, the outer diameter of the housing 1 is 4mm, and the inner diameter of the rotating cavity 1011 is 3.6mm. This servo sensor has successfully achieved further miniaturization by optimizing and improving the structure of the housing 1, the resistor plate 3, and the rotating shaft 2 in the prior art, providing a design scheme and manufacturing process for the servo sensor with a diameter of less than 4mm.

[0042] A method for manufacturing a resistor plate 3 for a potentiometer includes the following steps:

[0043] S10 processes the resistive plate 3 into a plate of a preset shape through machining;

[0044] The S20 exposure process combines a mask or photomask onto the board body, subtracting the copper area on the board body except for the conductive sheet area, to obtain a highly accurate effective angle. The exposure process can accurately determine the conductive and resistive areas of the resistor board 3, which greatly improves the positional accuracy of the conductive sheet and thus the resistor sheet 302 in the ultra-micro resistor board 3 compared to existing processes.

[0045] S30 applies an insulating layer to the working area of ​​the board; the insulating layer can eliminate the step surface at the junction of the carbon film and the conductive sheet, prevent the V-shaped brush claw from contacting the resistor sheet 302 and the conductive sheet at the same time, and make the thickness of the resistor sheet 302 uniform at both ends, eliminating the dummy position of the effective angle and making the true effective angle of the potentiometer closer to the designed effective angle.

[0046] S40 prints a carbon film on the insulating layer of the resistor 302 region of the plate to form the resistor 302;

[0047] S50 has abrasion-resistant conductive paint printed on the conductive sheet.

[0048] An ultra-miniature servo sensor includes a housing 1, a rotating shaft 2, and a resistor plate 3 disposed within the housing 1. The resistor plate 3 is manufactured by the aforementioned method for producing a resistor plate 3 for a potentiometer.

[0049] Compared with existing technologies, this invention has the following advantages: The structure of the housing 1, resistor plate 3, and rotating shaft 2 in the prior art has been optimized and improved. Simultaneously, the processing technology of the resistor plate 3 has also been optimized, ensuring that its processing accuracy is not affected while reducing its size. This successfully achieves further miniaturization of the servo sensor, providing a design scheme and processing technology for a servo sensor within 4mm.

[0050] The above description is only a preferred embodiment of this application. It should be noted that for those skilled in the art, several improvements and substitutions can be made without departing from the technical principles of this application, and these improvements and substitutions should also be considered within the scope of protection of this application.

Claims

1. A miniature servo sensor, characterized in that, include: The housing includes an outer shell and a bottom cover embedded at the bottom of the outer shell. The bottom cover has a limiting ring and a first through hole corresponding to the rotating shaft at the middle position. The outer shell has a rotating cavity for accommodating the brush fixing plate and a non-circular accommodating cavity for accommodating the resistor plate, arranged sequentially from top to bottom. A resistor plate is fixed inside the housing, and its shape corresponds to the shape of the receiving cavity. A second through hole is provided in the middle of the resistor plate for the rotating shaft to pass through. One side of the resistor plate is provided with a resistor sheet and a conductive sheet corresponding to the brush, and the other side is provided with a wiring conductive sheet. A rotating shaft is rotatably disposed within the housing. A connecting hole is provided in the middle of the rotating shaft, which is sequentially connected to the second through hole and the first through hole. A brush fixing plate for mounting the brush extends from the side of the rotating shaft. The upper end of the brush fixing plate is in close contact with the inner wall of the upper end of the housing, and the lower end is provided with a fixing post for fixing the brush. The upper end of the rotating shaft is attached to the inner wall of the housing through the brush fixing plate, and the lower end extends into the limiting ring and abuts against the bottom cover.

2. The ultra-miniature servo sensor according to claim 1, characterized in that, The conductive sheet includes a first conductive sheet, a second conductive sheet, and a third conductive sheet. The first and second conductive sheets are respectively disposed at both ends of the resistor sheet, and the third conductive sheet and the resistor sheet are respectively disposed on both sides of the second through hole.

3. The ultra-miniature servo sensor according to claim 2, characterized in that, An insulating region is provided between the first conductive sheet, the second conductive sheet and the third conductive sheet.

4. The ultra-miniature servo sensor according to claim 2, characterized in that, The brush is a C-type brush, and a fixing hole corresponding to the fixing post is provided in the middle of the brush. The brush is fixed to the lower side of the brush fixing plate through the fixing hole. Brush claws extend symmetrically on both sides of the brush and are respectively connected to the third conductive sheet and the resistive sheet.

5. The ultra-miniature servo sensor according to claim 4, characterized in that, The distance between the brush fixing plate and the resistor plate is 0.5-0.7mm.

6. The ultra-miniature servo sensor according to claim 1, characterized in that, The limiting ring has a slot to avoid the welding point.

7. The ultra-miniature servo sensor according to claim 1, characterized in that, The bottom cover is interference-fitted with the inner wall of the outer shell, and a gap is left between the bottom cover and the resistor plate.

8. The ultra-miniature servo sensor according to claim 1, characterized in that, The outer diameter of the housing is 4 mm, and the inner diameter of the rotating cavity is 3.6 mm.

9. A method for manufacturing a resistor plate for a potentiometer, used in the ultra-miniature servo sensor according to any one of claims 1-8, characterized in that, Includes the following steps: S10 obtains a pre-shaped plate body from the resistor plate body through machining; The S20 exposure plate incorporates a photomask onto the plate body, subtracting the copper area on the plate body excluding the conductive sheet area to obtain a highly accurate effective angle. S30 applies an insulating layer to the working area of ​​the plate; S40 Prints a carbon film on the insulating layer of the resistor sheet area of ​​the plate to form a resistor sheet; S50 has abrasion-resistant conductive paint printed on the conductive sheet.

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