An angular displacement sensor based on injection-molded resistance ring

Abstract

The present invention proposes an angular displacement sensor based on an injection-molded resistor ring, belonging to the field of measurement and testing technology. The sensor comprises a base, a bearing, a stop pin, a resistor assembly, a brush shaft assembly, a brush assembly, and an upper cover. The stop pins are located in two locations, and the resistor assembly comprises three sets, coaxially connected in series. The resistor assembly includes a synthetic resistor film, a conductive strip, a resistor ring, and a rivet. The rivet is embedded and fixed to the resistor ring. The brush shaft assembly comprises a transmission shaft, a lower connecting sleeve, an upper connecting sleeve, and three sets of brush assemblies. The transmission shaft is hinged to the upper cover and fixed coaxially with the rudder shaft. The three sets of brush assemblies are respectively arranged on one side of the resistor assembly near the upper cover. The lower connecting sleeve and the upper connecting sleeve are respectively fixed coaxially with the transmission shaft. The brush assembly comprises a slip ring and two sets of brushes. The first, second, and third resistor assemblies, and the upper cover are sequentially connected in series and then fixed to the base. The present invention solves the problems of poor linear accuracy and electrical reliability of existing angular displacement sensors.

Description

Technical Field

[0001] The invention belongs to the technical field of measurement and testing, and in particular relates to an angular displacement sensor based on an injection-molded resistance ring. Background Art

[0002] Servomechanisms are a general term for the actuator subsystems of aerospace flight control systems in my country, and high-power electric servomechanisms are a key research area. The angular displacement sensors used in these high-power servomechanisms are highly accurate, reliable, and triple-redundant. The actuators form a triple-redundant electromechanical servo actuator, each containing an angular displacement sensor. Each servomechanism contains four angular displacement sensors. These sensors, when powered by an external power supply, convert mechanical swing angle signals into electrical output signals for measuring engine rotation angle.

[0003] The installation location of the angular displacement sensor of aerospace is special, the space is limited, the vibration level is large, the alignment of the electrical zero position of the angular displacement sensor and the mechanical zero position of the rudder shaft is complex, the rivets at the input and output connections are easy to loosen, and the electrical reliability is low. It is difficult to achieve electrical zero and mechanical zero position alignment for ordinary angular displacement sensors in a limited installation space, which requires a lot of time and effort. In order to meet the system requirement of the output zero position voltage of the triple redundancy being less than 10mmV, it can only be achieved through system compensation, but system compensation wastes system resources and reduces the software resources of the servo system. In an environment with large-scale vibration, the electrical reliability of ordinary angular displacement sensors is low. The existing angular displacement sensor structure adopts a riveted forming method of resistor ring and rivet. During the riveting process of the resistor ring and rivet, the resistor ring will bear the stress from the external riveted rivet. The matrix of the resistor ring will undergo stress deformation after forming, which changes the linearity of the resistor body and reduces the linear accuracy of the angular displacement sensor. At the same time, during the vibration process, the rivets at the input and output connections are easy to loosen and rotate, resulting in input and output disconnection.

[0004] At present, the angular displacement sensors at home and abroad mainly include potentiometer type, photoelectric type, electromagnetic type and rotary transformer type. The photoelectric type has poor vibration resistance, the electromagnetic type is sensitive to interference from strong magnetic fields, and the output signal of the rotary transformer type is seriously interfered with. The widely used resistor body rivet riveted forming type angular displacement sensor has serious cracking of the resistance ring and the linearity changes significantly under stress. These types of angular displacement sensors are difficult to meet the angular displacement measurement needs of the rudder shaft of the control cabin of high-power aerospace vehicles.

[0005] In summary, the existing angular displacement sensors have poor linear accuracy and electrical reliability, and are prone to cracking of the resistance ring due to stress, so improvements are needed. Summary of the Invention

[0006] The present invention provides an angular displacement sensor based on an injection-molded resistance ring, aiming to solve the problems of poor linear accuracy and electrical reliability of existing angular displacement sensors, and the resistance ring being prone to cracking due to stress.

[0007] The object of the present invention is achieved through the following technical solutions:

[0008] An angular displacement sensor based on an injection-molded resistance ring comprises a base, a bearing, a limit pin, a resistance assembly, a brush shaft assembly, an electric brush assembly and an upper cover; there are two limit pins for limiting the movement of the brush within the effective mechanical travel range of the resistance film; there are three sets of resistance assemblies, which are coaxially arranged in series, namely the first resistance assembly, the second resistance assembly and the third resistance assembly; the resistance assembly comprises a synthetic resistance film, a conductive strip, a resistance ring and a rivet; the resistance ring and the rivet adopt an injection-molded integral molding structure, the rivet is embedded and fixed on the resistance ring, and is welded and fixed to the input and output leads; the brush shaft assembly comprises a transmission shaft, a lower connecting sleeve, an upper connecting sleeve and three sets of brush assemblies; one end of the transmission shaft is hinged and fixed to the upper cover, and the other end passes through the end face of the base and is coaxially fixed to the rudder shaft; the three sets of brush assemblies are respectively arranged The first resistor assembly, the second resistor assembly and the third resistor assembly are arranged on one side close to the upper cover; the lower connecting sleeve and the upper connecting sleeve are respectively fixed coaxially with the transmission shaft; the lower connecting sleeve is arranged between the first resistor assembly and the second resistor assembly, and the upper connecting sleeve is arranged between the second resistor assembly and the third resistor assembly; the lower connecting sleeve and the upper connecting sleeve rotate synchronously with the transmission shaft; the brush assembly includes a slip ring and two sets of brushes, the slip ring is coaxially fixed and synchronously rotated with the transmission shaft through the lower connecting sleeve or the upper connecting sleeve, the brushes are fixed on the slip ring and are close to the synthetic resistance film, the installation positions of the two sets of brushes are 180° rotationally symmetrical along the transmission shaft, the conductive strips are glued to the resistance rings, and are symmetrically installed with the resistance film; the first resistor assembly, the second resistor assembly, the third resistor assembly and the upper cover are connected in series in sequence and then fixed to the base.

[0009] As a preferred solution, the rivet is an integrated structure, including a coaxially arranged nail cap, a necked slot and a nail tail. A first mounting hole is axially arranged on the nail cap, and a second mounting hole is axially arranged on the nail tail. The first mounting hole is a countersunk hole, and the second mounting hole is a pin shaft hole.

[0010] As a preferred solution, the necked slot is used for inlaying and fixing, the outer diameters of the nail cap and the nail tail are equal and larger than the outer diameter of the necked slot, the first mounting hole is a countersunk hole, and the second mounting hole is a pin shaft hole.

[0011] As a preferred solution, a knurled structure is further provided at the junction of the nail cap, the necking slot and the outer surface of the nail tail with the resistance ring.

[0012] As a preferred solution, the brush shaft assembly further includes a bearing. The bearing has two discs, which are respectively arranged at both ends of the transmission shaft.

[0013] As a preferred solution, the conductive strip is made of sheet-like beryllium bronze QBb2C and is glued to the resistor ring with epoxy resin.

[0014] As a preferred solution, the brushes of the brush assembly are made of palladium-iridium alloy wire.

[0015] As a preferred solution, the synthetic resistor film is prepared by spraying a resistor liquid formula onto the resistor ring.

[0016] As a preferred solution, the rivet is made of brass material through machining and the surface is silver-plated.

[0017] The beneficial technical effects achieved by the present invention are:

[0018] The design of a triple-redundant resistor ring axial series structure achieves the system requirement of a triple-redundant output zero voltage of less than 10 mmV, eliminating the need for system software compensation and improving the servo system's software resource efficiency. The integrated injection molding of the resistor ring and rivet solves the low linear accuracy issue of traditional angular displacement sensors. This design also eliminates the problem of stress cracking in the resistor ring during the riveting process, improving product qualification rates and reducing production costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a structural schematic diagram of one specific embodiment of the present invention;

[0020] Figure 2 yes Figure 1 A top-down cross-sectional view of

[0021] Figure 3 This is a schematic diagram of the resistance ring structure of one specific embodiment of the present invention;

[0022] Figure 4 yes Figure 3 Cross-section at AA in the middle;

[0023] Figure 5 This is a schematic diagram of the relationship between parameters related to resistance values ​​in one specific embodiment of the present invention;

[0024] Figure 6 This is a schematic diagram of the rivet structure used in the prior art;

[0025] Figure 7 This is a schematic diagram of a rivet structure according to one specific embodiment of the present invention;

[0026] Figure numerals: 1. base; 2. bearing; 3. limit pin; 4. first resistor assembly; 5. second resistor assembly; 6. third resistor assembly; 7. brush shaft assembly; 8. lower connecting sleeve; 9. upper connecting sleeve; 10. brush assembly; 11. upper cover; 12. synthetic resistor film; 13. conductive strip; 14. resistor ring; 15. screw; 16. rivet; 17. traditional rivet; 161. nail cap; 162. necking slot; 163. nail tail; 164. first mounting hole; 165. second mounting hole. DETAILED DESCRIPTION

[0027] The technical solution of the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments. It is apparent that the embodiments described are only a portion of the embodiments of the present invention, not all of them. All other embodiments derived by those skilled in the art based on the embodiments of the present invention without inventive effort are also within the scope of protection claimed by the present invention.

[0028] like Figures 1 to 7 As shown in the figure, a specific embodiment of an angular displacement sensor based on an injection-molded resistance ring includes a base 1, a bearing 2, a limit pin 3, a resistance assembly, a brush shaft assembly 7, a brush assembly 10, and an upper cover 11. For ease of description, in this specific embodiment, the directions are defined based on the mounting plane and axial direction of the base 1. The mounting plane of the base 1 is perpendicular to the end surface. Figure 1 The direction perpendicular to the mounting plane of the base 1 is inward, that is, the direction perpendicular to the paper is the front, and the direction perpendicular to the outside is the back; the side of the mounting plane of the base 1 close to the circular hole, that is, Figure 1 The left side is the left, the side close to the U-shaped groove is the right; the side perpendicular to the end face of the base 1 and away from the end face is the right. Figure 1 The upper part in the middle is the top, and the side close to the end face is the bottom.

[0029] In this specific embodiment, there are two limit pins 3, which function to limit the movement of the brush within the effective mechanical travel range of the resistor film. There are three sets of resistor assemblies, coaxially arranged in series, namely the first resistor assembly 4, the second resistor assembly 5, and the third resistor assembly 6. The resistor assembly includes a synthetic resistor film 12, a conductive strip 13, a resistor ring 14, and a rivet 16. The synthetic resistor film 12 is a key component of the sensor. The brush assembly 10 moves on the synthetic resistor film 12 of the resistor assembly to pick up the corresponding voltage signal output. The synthetic resistor film 12 is made by spraying a resistor liquid formula on the resistor ring 14.

[0030] In the prior art, the resistance ring 14 is formed by die pressing, and the rivets are assembled to the resistance ring 14 by riveting. The key steps of the process include:

[0031] S1. Heat treatment of skeleton plate;

[0032] S2, machining dimensions, the machining process includes 13 steps;

[0033] S3, spray film;

[0034] S4, riveting rivets;

[0035] S5, hot aging, set the temperature to 125 ° C, refining for 12 hours;

[0036] S6. Silver filling and drying, set the temperature to 150℃ and dry for 1 hour.

[0037] like Figures 3-4 As shown, in this specific embodiment, the resistance ring 14 and the rivet 16 are formed by injection molding, and no assembly is required. The key steps of the process include:

[0038] S101, re-inspection of injection molded skeleton;

[0039] S102, machining deburring and chamfering, there are only two steps in the machining process;

[0040] S103, spraying film;

[0041] S104, hot aging, set the temperature to 125 ° C, and refine for 12 hours;

[0042] S105, silver filling and drying, set the temperature to 150℃, and dry for 1 hour.

[0043] Compared with the existing method of compression molding followed by riveting, the structural design of integrated injection molding reduces the processing steps, reduces the production time, shortens the production cycle, and improves product performance. The performance comparison of compression molding and injection molding designs is shown in Table 1:

[0044] Table 1 Performance comparison of compression molding and injection molding designs

[0045]

[0046]

[0047] From the comparative analysis in Table 1, it can be seen that the performance of the injection molding design is significantly better than that of the traditional compression molding design.

[0048] In the prior art, rivets are attached after the resistor ring is formed. The tail end of the rivet is subjected to stress and flips, squeezing the resistor ring base. During this stressful flipping process, the resistor ring is also subjected to stress and deforms, which can easily cause cracking. Because the resistor film is sprayed onto the resistor ring base and undergoes linear trimming to achieve the required linear accuracy, deformation of the resistor ring base changes the width of the resistor film, causing a change in the resistance value per unit length of the resistor film.

[0049] like Figure 5 As shown, under the condition of unchanged environmental conditions, the resistance value R is mainly affected by three factors, and the influencing relationship is as follows:

[0050]

[0051] Where ρ represents the resistivity of the resistor film material, L represents the length of the resistor body, and S represents the cross-sectional area of ​​the resistor body.

[0052] According to the above analysis, during the riveting process between the resistor ring and the rivet in the prior art, the resistor ring is deformed by stress, which changes the cross-sectional area S of the resistor body, thereby changing the resistance value per unit length and affecting the linear accuracy of the entire resistor body.

[0053] In this specific embodiment, the resistance ring 14 and the rivet 16 are designed by injection molding, and do not require riveting installation, which solves the problem of stress cracking of the resistance ring during the riveting process, improves the product qualification rate, reduces production costs, and shortens the production cycle.

[0054] like Figure 6 As shown, due to installation process limitations, conventional rivets 17 in the prior art have a main body outer diameter of 2 mm. This further reduces strength after the hole is opened, and the preload force during installation cannot be too high. In a vibrating environment, conventional rivets 17 are prone to axial rotation and radial loosening. Since both ends of conventional rivets 17 are connected to input and output wires, rotation or loosening of conventional rivets 17 can easily cause input or output disconnection, affecting product reliability.

[0055] like Figure 7As shown, in this embodiment, rivet 16 is machined from brass and silver-plated. Rivet 16 is a one-piece structure, comprising a coaxially arranged cap 161, a necking slot 162, and a tail 163. A first mounting hole 164 is axially provided on cap 161, and a second mounting hole 165 is axially provided on tail 163. In this embodiment, the outer diameter of necking slot 162 is 2 mm, for mounting and fixing. Both cap 161 and tail 163 have outer diameters of 3 mm. First mounting hole 164 is a countersunk hole with a size of ￠1 x 1 mm. Second mounting hole 165 is a pin hole with a size of ￠1.6 x 2.3 mm. To increase friction, enhance the connection strength between rivet 16 and resistor ring 14, improve reliability, and prevent axial rotation of the rivet, knurling is provided at the junction of the outer surfaces of cap 161, necking slot 162, and tail 163 with resistor ring 14. It should be noted that the material and dimensions of the rivet 16 can be adjusted to meet specific needs. The parameters in this embodiment are provided for clarity and ease of understanding only and are not intended to be limiting. The cap 161, the necked slot 162, and the tail 163 can also employ non-circular cross-sections to similarly prevent axial rotation between the rivet 16 and the resistor ring 14, without substantial differences from this embodiment.

[0056] In this embodiment, rivet 16 is secured to resistor ring 14 via a constricted slot 162. Input and output leads are welded together via cap 161 and tail 163. Cap 161, constricted slot 162, and tail 163 all provide radial fixation. A knurled structure at the junction with resistor ring 14 prevents axial rotation. This effectively prevents axial rotation or radial loosening of rivet 16 in a vibrating environment, eliminating the potential risk of input or output disconnection due to unreliable rivet 16 fixation and improving product reliability.

[0057] In this specific embodiment, the brush shaft assembly 7 comprises a transmission shaft, a lower connecting sleeve 8, an upper connecting sleeve 9, and three sets of brush assemblies 10. The number, specifications, and location of the brush assemblies 10 are adjusted according to the specific requirements of the resistor assembly. The bearing 2 comprises two discs, one at each end of the transmission shaft, providing support and reducing friction. A sleeve or other bearing structure may also be used depending on actual needs. One end of the transmission shaft is secured to the upper cover 11 via a bearing, while the other end passes through the end surface of the base 1 and is coaxially secured to the rudder shaft. The transmission shaft and base 1 are secured via a bearing. The three sets of brush assemblies 10 are respectively located on the side of the first resistor assembly 4, the second resistor assembly 5, and the third resistor assembly 6 near the upper cover 11. They move over the corresponding resistor assembly to pick up the voltage output. The lower connecting sleeve 8 and the upper connecting sleeve 9 are coaxially secured to the transmission shaft, connecting the brush assemblies 10 to the transmission shaft, adjusting the axial distance between adjacent brush assemblies 10, and providing insulation between the brush assemblies 10. The lower connecting sleeve 8 is arranged between the first resistor assembly 4 and the second resistor assembly 5, and the upper connecting sleeve 9 is arranged between the second resistor assembly 5 and the third resistor assembly 6. The lower connecting sleeve 8 and the upper connecting sleeve 9 are connected to the transmission shaft by interference fit, and circumferential positioning is achieved by radially arranged limit pins.

[0058] The brush assembly 10 is screwed to the lower connecting sleeve 8 or the upper connecting sleeve 9. It consists of a slip ring and two sets of brushes. The slip ring is coaxially fixed to the drive shaft via the lower connecting sleeve 8 or the upper connecting sleeve 9, allowing for synchronous rotation. The brushes are screwed to the slip ring, relying on their elasticity to maintain close contact with the synthetic resistor film 12. The two sets of brushes are installed symmetrically along the drive shaft, 180° in rotation. The conductive strip 13 is made of sheet-like beryllium bronze QBb2C and is glued to the resistor ring 14 with epoxy resin, forming a symmetrical installation with the resistor film. The curvature of the conductive strip is 162°, which can be adjusted according to actual needs. After attachment, it is sprayed with two coats of resistance liquid. The resistance between the longest two points of the conductive strip 13 should be less than 10'Ω. The brushes slide across the synthetic resistor film 12 to pick up the voltage, which is then output through the conductive strip 13. In this specific embodiment, the brushes adopt a triple-redundant solution, have a unique finger-shaped structure, and are made of palladium-iridium alloy wire.

[0059] The base 1 serves as a mounting flange and is fixed to the cabin or other base by screws. The first resistor assembly 4, the second resistor assembly 5, the third resistor assembly 6 and the upper cover 11 are connected in series in sequence and fixed to the base 1. In this specific embodiment, a stop structure is provided on the mounting surface of the base 1, the upper cover 11 and the three sets of resistor assemblies. While achieving axial fixation by plugging, adjacent components can rotate relative to each other along the axial direction, thereby realizing a triple-redundant design. The first resistor assembly 4, the second resistor assembly 5 and the third resistor assembly 6 are fixed by screws 15. The mounting hole of the screw 15 is an arc-shaped long hole. Its hole shape is similar to an oblong hole, except that the side wall between the two side arcs is also set to an arc shape. Its function is to adjust the mechanical zero position of the resistor assembly to coincide with the electrical zero position.

[0060] The electrical zero position and mechanical zero position alignment of the triple-redundant angular displacement sensor is the final link of the angular displacement sensor, which determines the electrical zero position output accuracy of the triple-redundant angular displacement sensor. In the limited installation space, it is difficult for traditional angular displacement sensors to achieve the requirement of electrical zero position and mechanical zero position alignment output less than 10mmV, which is generally within the range of about 20mmV. Therefore, it can only be achieved through system compensation, but system compensation will waste system resources and reduce the software resources of the servo system.

[0061] In this specific embodiment, a design of upper and lower plug-in connection and axial rotation is adopted between the three resistor components. When in use, the installation position of the first resistor component 4 is used as a reference, and the second resistor component 5 is used as a reference to the first resistor component 4, and the electrical zero position output by each other is less than 10mmv. Then, the third resistor component 6 is rotated and adjusted based on the second resistor component 5, so that the electrical zero position output between the second resistor component 5 and the third resistor component 6 is less than 10mmv. Finally, through differential adjustment of the three resistor components, the three redundant electrical outputs are all less than 10mmv output, thereby realizing the electrical zero position and mechanical zero position alignment of the angular displacement sensor.

[0062] The beneficial technical effects achieved by this specific embodiment include:

[0063] 1. A triple-redundant resistor ring axial series structure was designed. This structure features easily adjustable alignment of the electrical and mechanical zero positions, achieving the system requirement of a triple-redundant output zero voltage of less than 10 mmV without requiring system software compensation, thereby improving the servo system's software resource utilization efficiency. The angular displacement sensor employing this structure provides independent and reliable electrical input and output, significantly improving the three-channel zero misalignment and reliability compared to existing solutions. Furthermore, the underlying technology is relatively mature, resulting in a high product qualification rate, low production costs, and ease of implementation.

[0064] 2. The integrated injection molding structure design of the resistor ring and rivet solves the problem that during the riveting process of the traditional angular displacement sensor resistor ring and rivet, the resistor ring undergoes stress deformation when it is subjected to external riveting stress, resulting in low linearity of the resistor body and reduced linear accuracy of the angular displacement sensor.

[0065] 3. By adopting the integrated injection molding structure design of the resistance ring and rivet, the problem of stress cracking of the resistance ring during the riveting process of the resistance ring and the rivet is solved, the product qualification rate is improved and the production cost is reduced.

[0066] 4. The knurled structure is adopted on the joint surface of the resistance ring and the rivet, which is beneficial to improve the axial stability of the rivet and the resistance ring after injection molding, reduce the probability of system failure, and avoid the problem of axial rotation of the traditional angular displacement sensor rivet during vibration causing input or output circuit breakage of the electrical system and reducing system reliability.

[0067] In summary, the technical solution proposed in this specific embodiment solves the problems of poor linear accuracy and electrical reliability of existing angular displacement sensors, and the proneness of resistance rings to cracking due to stress, and has outstanding substantial features and significant progress.

Claims

1. An angular displacement sensor based on an injection-molded resistance ring, characterized in that: It comprises a base (1), a bearing (2), a limit pin (3), a resistor assembly, a brush shaft assembly (7), a brush assembly (10) and an upper cover (11); The limit pins (3) are provided at two locations for limiting the movement of the brush within the effective mechanical travel range of the resistance film; the resistance components are provided in three sets, which are coaxially arranged in series, namely a first resistance component (4), a second resistance component (5) and a third resistance component (6); the resistance components include a synthetic resistance film (12), a conductive strip (13), a resistance ring (14) and a rivet (16); The resistance ring (14) and the rivet (16) are of an integral injection-molded structure; the rivet (16) is embedded and fixed on the resistance ring (14) and is welded and fixed to the input and output leads; The brush shaft assembly (7) comprises a transmission shaft, a lower connecting sleeve (8), an upper connecting sleeve (9) and three sets of brush assemblies (10); one end of the transmission shaft is hingedly fixed to the upper cover (11), and the other end passes through the end surface of the base (1) and is coaxially fixed to the rudder shaft; the three sets of brush assemblies (10) are respectively arranged on one side of the first resistor assembly (4), the second resistor assembly (5) and the third resistor assembly (6) close to the upper cover (11); the lower connecting sleeve (8) and the upper connecting sleeve (9) are respectively coaxially fixed to the transmission shaft; the lower connecting sleeve (8) is arranged between the first resistor assembly (4) and the second resistor assembly (5), and the upper connecting sleeve (9) is arranged between the second resistor assembly (5) and the third resistor assembly (6); the lower connecting sleeve (8) and the upper connecting sleeve (9) rotate synchronously with the transmission shaft; The brush assembly (10) comprises a collector ring and two sets of brushes. The collector ring is fixed coaxially with the transmission shaft through a lower connecting sleeve (8) or an upper connecting sleeve (9) and rotates synchronously. The brushes are fixed on the collector ring and closely adhere to the synthetic resistance film (12). The installation positions of the two sets of brushes are symmetrical along the transmission shaft by 180 degrees. The conductive strip (13) is glued to the resistance ring (14) and forms a symmetrical installation with the resistance film. The first resistance assembly (4), the second resistance assembly (5), the third resistance assembly (6) and the upper cover (11) are sequentially connected in series and then fixed on the base (1).

2. The angular displacement sensor according to claim 1, wherein: The rivet (16) is an integrated structure, comprising a coaxially arranged nail cap (161), a necking slot (162) and a nail tail (163); a first mounting hole (164) is axially arranged on the nail cap (161); a second mounting hole (165) is axially arranged on the nail tail (163); the first mounting hole (164) is a countersunk hole, and the second mounting hole (165) is a pin shaft hole.

3. The angular displacement sensor according to claim 2, wherein: The necked slot (162) is used for embedding and fixing, the outer diameters of the nail cap (161) and the nail tail (163) are equal and larger than the outer diameter of the necked slot (162), the first mounting hole (164) is a countersunk hole, and the second mounting hole (165) is a pin shaft hole.

4. The angular displacement sensor according to claim 2, wherein: A knurled structure is also provided at the junction of the outer surfaces of the nail cap (161), the necking slot (162) and the nail tail (163) with the resistance ring (14).

5. The angular displacement sensor according to claim 1, wherein: The brush shaft assembly (7) further comprises a bearing (2), wherein the bearing (2) has two discs, which are respectively arranged at both ends of the transmission shaft.

6. The angular displacement sensor according to any one of claims 1 to 5, characterized in that: The conductive strip (13) is made of sheet-like beryllium bronze QBb2C and is glued to the resistance ring (14) using epoxy resin.

7. The angular displacement sensor according to any one of claims 1 to 5, characterized in that: The brushes of the brush assembly (10) are made of palladium-iridium alloy wire.

8. The angular displacement sensor according to any one of claims 1 to 5, characterized in that: The synthetic resistor film (12) is prepared by spraying a resistor liquid formula onto a resistor ring (14).

9. The angular displacement sensor according to any one of claims 1 to 5, characterized in that: The rivet (16) is made of brass material through mechanical processing, and its surface is silver-plated.

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