Ultrathin hollow shaft angular displacement sensor

Abstract

The invention discloses an ultra-thin hollow shaft angular displacement sensor, and belongs to the technical field of angular displacement sensor production, the ultra-thin hollow shaft angular displacement sensor comprises a shell, a resistor body, a hollow shaft, a collector ring and a first electric brush, the hollow shaft is provided with a shaft bulge loop and a hollow shaft second annular groove, and the collector ring is provided with a collector ring first annular groove and a collector ring second annular groove. The shaft convex ring is arranged in the collector ring second annular groove, the part, close to the circumferential inner wall, of the collector ring is arranged in the hollow shaft second annular groove, and the corresponding part of the shell is arranged in the collector ring first annular groove. The resistor body is used for axially positioning the first end of the hollow shaft, the shell is used for axially positioning the collector ring, the collector ring is used for axially positioning the second end of the hollow shaft, and finally the function of axial positioning is achieved through structural changes of the hollow shaft and the collector ring. Therefore, a smaller axial size, namely the thickness of the sensor, can be realized and can be as low as 4mm, and the application requirements of the ultra-thin angular displacement sensor are better met.

Description

Technical Field

[0001] The present invention belongs to the technical field of angular displacement sensor (also called angular displacement positioner), and in particular relates to an ultra-thin hollow shaft angular displacement sensor. Background Art

[0002] Angular displacement sensor is an adjustable electronic component that changes the output potential by changing a certain electrical parameter (resistance, capacitance, inductance, mutual inductance, self-inductance, magnetic flux, etc.) in a certain way. It generally converts the mechanical input (rotation angle) into an electrical output (resistance value, capacitance, inductance, mutual inductance, self-inductance, magnetic resistance, voltage value, output ratio, etc.) with a certain corresponding relationship; or converts the electrical input into a mechanical output with a certain corresponding relationship. Angular displacement sensor is often used as a rudder angle feedback element in the system and is one of the important components of the system.

[0003] Conventional angular displacement sensors are relatively large and thick (i.e., the axial dimension is large, generally above 10mm). In fields such as aerospace, the demand for miniaturization of angular displacement sensors is becoming more and more urgent, especially for ultra-thin angular displacement sensors. For example, some special applications require a thickness within the range of 4-5mm, high detection accuracy, light weight, and ease of processing and assembly.

[0004] Among the traditional ultra-thin angular displacement sensors, the utility model patent product applied for by the applicant in 2022 is the closest to meeting the above requirements. The patent number of the utility model is "202221005348.6" and the name is "an ultra-thin hollow angular displacement sensor". The utility model omits the traditional bearing, insulating sleeve and cover plate, and significantly reduces the axial thickness, overall volume and mass of the angular displacement sensor. However, the utility model still has the following defects:

[0005] First, the collector ring is positioned and connected by the gasket and the hollow shaft, and the gasket will occupy the axial space. Although the axial space corresponding to the gasket must exist due to the installation of the brush, the axial dimension of the gasket needs to meet the welding requirements and the hollow shaft needs to be provided with a convex ring and the gasket to axially limit the collector ring. These factors inevitably lead to the axial dimension of the sensor cannot be made smaller, that is, the thickness of the sensor cannot be further reduced due to structural limitations, and can only reach a minimum of 4.5mm.

[0006] Second, in order to achieve a reliable connection between the shell and the resistor body, the shell and the resistor body are welded together. In order to achieve a reliable connection between the hollow shaft and the collector ring, a gasket is added and connected by welding. These welding structures require that the associated parts must be metal. That is to say, the shell, the peripheral part of the resistor body, the collector ring, the gasket and the hollow shaft in the utility model are all made of metal or most of them are made of metal. There are two defects: First, in order to maintain the insulation performance, necessary gaps must be reserved between the collector ring and the shell, between the gasket and the resistor body, and between the hollow shaft and the shell, which structurally limits the further reduction of the product thickness and volume; second, the large amount of metal material will inevitably lead to an increase in the mass of the entire sensor, which is not conducive to meeting the lightweight requirements. If it is replaced with a plastic material, how to achieve a reliable connection between the shell and the resistor body, and between the hollow shaft and the collector ring (including anti-rotation and anti-loosening connection functions) is a difficult problem. No such technical solution that can be applied to this ultra-thin angular displacement sensor has been found in the prior art, so it is impossible to obtain technical inspiration from any prior art.

[0007] Third, because the necessary gap required for relative rotation needs to be retained between one end of the hollow shaft and the resistor body, and between the other end of the hollow shaft and the outer shell, there are two defects: on the one hand, the gap may cause the hollow shaft to tilt or sway during rotation, thereby affecting the reliability of contact sliding between the brush and the resistor body and reducing the detection accuracy; on the other hand, the gap leads to poor sealing performance at both ends of the hollow shaft and unsatisfactory dustproof effect. Dust entering the outer shell may reduce the rotation flexibility of the rotating parts and affect the normal operation of the sensor. Summary of the invention

[0008] The purpose of the present invention is to provide an ultra-thin hollow shaft angular displacement sensor with smaller thickness and volume, lighter weight and higher detection accuracy in order to solve the above problems.

[0009] The present invention achieves the above-mentioned purpose through the following technical solutions:

[0010] An ultra-thin hollow shaft angular displacement sensor comprises a shell, a resistor, a hollow shaft, a collector ring and a first brush, wherein the resistor is placed in the shell and connected to a first end of the shell, the first end of the hollow shaft passes through a central through hole of the resistor, a position near the first end of the circumferential outer wall of the hollow shaft is provided with a first hollow shaft annular groove whose outer wall is concave to form an "L"-shaped radial cross section, a portion of the resistor close to its circumferential inner wall is placed in the first hollow shaft annular groove, the second end of the hollow shaft passes through the central through hole of the collector ring and is connected to the collector ring, the collector ring is located in the second end of the shell, the first brush is mounted on the collector ring and is in contact with a working band on the resistor The circumferential outer wall of the hollow shaft near the second end bulges outward in the circumferential direction to form a shaft convex ring, the part of the hollow shaft between the second end and the shaft convex ring forms a second annular groove of the hollow shaft with a radial cross section of "L" shape, the circumferential outer wall of the collecting ring near the second end of the hollow shaft is concave to form a first annular groove of the collecting ring with a radial cross section of "L" shape, a section of the circumferential inner wall of the collecting ring away from the second end of the hollow shaft is concave to form a second annular groove of the collecting ring with a radial cross section of "L" shape, the shaft convex ring is placed in the second annular groove of the collecting ring, the part of the collecting ring near the circumferential inner wall is placed in the second annular groove of the hollow shaft, and the part of the outer shell near the second end inner wall is placed in the first annular groove of the collecting ring.

[0011] Preferably, in order to realize a reliable anti-rotation and anti-loosening positioning connection structure between the resistor body and the shell, and between the hollow shaft and the collector ring, the circumferential outer wall of the resistor body is provided with positioning bosses protruding toward the outer circumference on two opposite sides, and the circumferential wall of the first end of the shell is provided with positioning grooves on two opposite sides, and the two positioning bosses are respectively placed in the two positioning grooves, and a hollow shaft thread is provided on the groove wall corresponding to the circumferential inner wall of the collector ring in the second annular groove of the hollow shaft, and a collector ring thread is provided on the circumferential inner wall of the collector ring, and the hollow shaft thread and the collector ring thread do not contact each other and are connected by a sealant filled in the second annular groove of the hollow shaft.

[0012] Preferably, in order to further improve the positioning and connection function between the resistor body and the shell and more reliably prevent the resistor body from detaching from the shell, a plurality of resistor body pin holes evenly distributed along the circumferential direction are provided on the circumferential outer wall of the resistor body, and a plurality of shell pin holes evenly distributed along the circumferential direction are provided on the circumferential wall of the first end of the shell, and a plurality of positioning pins respectively pass through the plurality of shell pin holes and the plurality of resistor body pin holes.

[0013] Preferably, in order to further improve the positioning and connection function between the hollow shaft and the collector ring, the outer wall of the shaft cam ring on one side close to the resistor body is concave to form an annular positioning groove and the annular positioning groove is filled with sealant that is tightly connected to the corresponding groove wall of the second annular groove of the collector ring.

[0014] Preferably, in order to achieve a detection function with a larger angle range and facilitate the installation of leads, a second brush is installed on the resistor body, the second brush and the working band on the resistor body are insulated from each other, a conductive band conductively connected to the first brush is provided on the side surface of the collector ring close to the resistor body, the second brush is in contact with the conductive band, a lead groove is provided on the side surface of the resistor body away from the first brush, the second brush is connected to one end of the lead, the lead is placed in the lead groove, the other end of the lead passes through the corresponding lead notch on the outer shell and is placed outside the outer shell, and the lead groove is filled with sealant.

[0015] Preferably, in order to facilitate reliable installation of the first brush and ensure smooth rotation of the collector ring without increasing the axial dimension, the first brush is installed on the collector ring by rivets, and a concave clearance groove is provided on the inner wall of the second end of the housing at a position corresponding to the rivet.

[0016] Preferably, in order to further ensure that the rivet rotates smoothly with the collecting ring without increasing the axial dimension, the circumferential outer wall of the collecting ring close to the first annular groove of the collecting ring is concave to form a third annular groove of the collecting ring with an "L"-shaped radial cross-section, and the end of the rivet is placed in both the third annular groove of the collecting ring and the yield groove.

[0017] Preferably, in order to achieve better positioning and sealing effects, the inner wall surface of the portion of the circumferential inner wall of the shell located in the first annular groove of the collector ring is provided with a first concave sealing groove, and a first sealing ring is installed in the first sealing groove; the circumferential inner wall surface of the resistor body is provided with a second concave sealing groove, and a second sealing ring is installed in the second sealing groove.

[0018] Preferably, in order to improve the lubrication properties of the sealing ring to reduce friction, the first sealing ring and the second sealing ring are both polytetrafluoroethylene sealing rings.

[0019] Preferably, in order to further reduce product weight and facilitate quick alignment of the zero position during application, the hole wall near the second end of the central through hole of the hollow shaft is thinned toward the peripheral direction to form a hollow shaft countersunk hole, and the position near the collecting ring in the second end face of the outer shell and the bottom surface of the hollow shaft countersunk hole are respectively provided with corresponding zero position marking grooves or zero position marking lines.

[0020] The beneficial effects of the present invention are:

[0021] The present invention arranges a first annular groove and a second annular groove of the hollow shaft on the hollow shaft, arranges a first annular groove and a second annular groove of the collecting ring on the collecting ring, uses a resistor to axially position the first end of the hollow shaft, uses a shell to axially position the collecting ring, and uses the collecting ring to axially position the second end of the hollow shaft. When lubricating oil is applied, the positioning structure does not affect the normal rotation function of the hollow shaft and the collecting ring at all, and finally realizes the function of completing the axial positioning by using the structural changes of the hollow shaft and the collecting ring itself, cancels the traditional structure of relying on a gasket and designing a convex ring on the hollow shaft to cooperate with the gasket to realize axial positioning, thereby achieving a smaller axial size, that is, the sensor thickness, which can be as low as 4mm, and better meets the application requirements of ultra-thin angular displacement sensors; by designing a positioning boss and a positioning groove between the resistor and the shell The positioning and matching structure is designed with a thread + sealant matching positioning structure between the hollow shaft and the collector ring, which can realize the reliable anti-rotation and anti-loosening connection function between the resistor body and the shell, and between the hollow shaft and the collector ring without welding, so that each component can be made of plastic with strength that meets the requirements and smaller mass. Not only can the gap between the corresponding components that must be retained to ensure the insulation performance be reduced, but the plastic is lighter than metal, so the entire sensor has a better small volume and light weight effect; by adding sealing rings between the shell and the collector ring, and between the hollow shaft and the resistor body, on the one hand, the gap between the corresponding components can be reduced, thereby having a better positioning function, and the hollow shaft will not tilt or swing when rotating, thereby improving the detection accuracy. On the other hand, it has a better dustproof function, which prevents dust from entering the shell and affecting the normal operation of the sensor. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a front cross-sectional view of the ultra-thin hollow shaft angular displacement sensor of the present invention;

[0023] Figure 2 is a top view of the ultra-thin hollow shaft angular displacement sensor of the present invention;

[0024] Figure 3 is a three-dimensional diagram of the ultra-thin hollow shaft angular displacement sensor of the present invention, which is a top view;

[0025] Figure 4 It is a three-dimensional diagram of the housing of the ultra-thin hollow shaft angular displacement sensor of the present invention, and the figure is a bottom-up view;

[0026] Figure 5 It is a three-dimensional diagram of the resistor body of the ultra-thin hollow shaft angular displacement sensor of the present invention, and the figure is a top view;

[0027] Figure 6It is a bottom view of the resistor body of the ultra-thin hollow shaft angular displacement sensor of the present invention;

[0028] Figure 7 It is a front cross-sectional view of the hollow shaft of the ultra-thin hollow shaft angular displacement sensor of the present invention;

[0029] Figure 8 is a three-dimensional diagram of the hollow shaft of the ultra-thin hollow shaft angular displacement sensor of the present invention, which is a top view;

[0030] Fig. 9 It is a front cross-sectional view of the collector ring of the ultra-thin hollow shaft angular displacement sensor of the present invention;

[0031] Fig.10 It is a three-dimensional diagram of the collector ring of the ultra-thin hollow shaft angular displacement sensor of the present invention, and the figure is a top view. DETAILED DESCRIPTION

[0032] The present invention will be further described below in conjunction with the accompanying drawings:

[0033] like Figure 1-Figure 10 As shown, the ultra-thin hollow shaft angular displacement sensor of the present invention comprises a housing 3, a resistor 14, a hollow shaft 10, a collector ring 13 and a first brush 5, the resistor 14 is placed in the housing 3 and connected to the first end (the lower end in the figure) of the two ends of the housing 3, the first end (the lower end in the figure) of the two ends of the hollow shaft 10 passes through the central through hole of the resistor 14, a position near the first end of the circumferential outer wall of the hollow shaft 10 is provided with a hollow shaft first annular groove 31 with an outer wall concave to form a radial cross section of "L" shape, the portion of the resistor 14 close to its circumferential inner wall is placed in the hollow shaft first annular groove 31, the second end (the upper end in the figure) of the two ends of the hollow shaft 10 passes through the central through hole of the collector ring 13 and is connected to the collector ring 13, the collector ring 13 is located in the second end (the upper end in the figure) of the two ends of the housing 3, the first brush 5 is installed on the collector ring 13 and connected to the resistor 1 4 contacts the working belt 24 on the hollow shaft 10, the circumferential outer wall near the second end of the hollow shaft 10 protrudes toward the circumferential direction to form a shaft convex ring 11, the part of the hollow shaft 10 located between the second end and the shaft convex ring 11 forms a hollow shaft second annular groove 29 with a radial cross section of "L" shape, the circumferential outer wall near the second end of the hollow shaft 10 in the collecting ring 13 is concave to form a collecting ring first annular groove 35 with a radial cross section of "L" shape, a section of the circumferential inner wall away from the second end of the hollow shaft 10 in the collecting ring 13 (that is, the hole wall of the central through hole 38 of the collecting ring 13) is concave to form a collecting ring second annular groove 37 with a radial cross section of "L" shape, the shaft convex ring 11 is placed in the collecting ring second annular groove 37, the part of the collecting ring 13 close to the circumferential inner wall is placed in the hollow shaft second annular groove 29, and the part of the outer shell 3 close to the second end inner wall is placed in the collecting ring first annular groove 35.

[0034] like Figure 1-Figure 10 As shown, the present invention also discloses the following more optimized specific structures:

[0035] In order to realize a reliable anti-rotation and anti-loosening positioning connection structure between the resistor body 14 and the shell 3, and between the hollow shaft 10 and the collector ring 13, positioning bosses 18 protruding in the outer circumferential direction are respectively provided on the opposite sides of the circumferential outer wall of the resistor body 14, and positioning grooves 22 are respectively provided on the opposite sides of the circumferential wall of the first end of the shell 3. The two positioning bosses 18 are respectively placed in the two positioning grooves 22, and a hollow shaft thread 30 is provided on the groove wall corresponding to the circumferential inner wall of the collector ring 13 in the second annular groove 29 of the hollow shaft, and a collector ring thread 36 is provided on the circumferential inner wall of the collector ring 13, that is, on the hole wall of the center through hole 38 thereof. The hollow shaft thread 30 and the collector ring thread 36 do not contact each other and are connected by the sealant 8 filled in the second annular groove 29 of the hollow shaft. Note: The hollow shaft thread 30 and the collector ring thread 36 do not contact each other in order to ensure that the collector ring 13 can rotate freely relative to the hollow shaft 10 during the processing to achieve the function of adjusting the zero position. The hollow shaft thread 30 and the collector ring thread 36 are set to achieve the anti-rotation and anti-loosening positioning connection function between the hollow shaft 10 and the collector ring 13 through the sealant 8; the sealant 8 is also called binding glue, which realizes the sealing and / or filling connection function by solidifying from liquid to solid. It itself has no fixed shape for practical use, and its shape varies according to the actual structure. Therefore, all sealants 8 in this article use the same component names and marking numbers, but sealants 8 in different positions are not the same piece of sealant 8, let alone sealants 8 of the same shape.

[0036] In order to further improve the positioning and connection function between the resistor 14 and the shell 3 and more reliably prevent the resistor 14 from detaching from the shell 3, a plurality of (three in the figure) resistor pin holes 27 evenly distributed along the circumferential direction are provided on the circumferential outer wall of the resistor 14, and a plurality of (three in the figure) shell pin holes 20 evenly distributed along the circumferential direction are provided on the circumferential wall of the first end of the shell 3. A plurality of positioning pins 15 respectively pass through the plurality of shell pin holes 20 and the plurality of resistor pin holes 27 and are fixed by sealant 8.

[0037] In order to further improve the positioning and connection function between the hollow shaft 10 and the collector ring 13, the outer wall of the shaft convex ring 11 on one side close to the resistor body 14 is concave to form an annular positioning groove 28, and the annular positioning groove 28 is filled with a sealant 8 that is tightly connected to the corresponding groove wall of the second annular groove 37 of the collector ring.

[0038] In order to achieve a detection function with a larger angle range and facilitate the installation of the lead 2, a second brush 7 is installed on the resistor body 14, and the second brush 7 and the working belt 24 on the resistor body 14 are insulated from each other. A conductive belt 39 conductively connected to the first brush 5 is provided on the side surface of the collector ring 13 close to the resistor body 14, and the second brush 7 contacts the conductive belt 39. A lead groove 25 is provided on the side surface of the resistor body 14 away from the first brush 5. The second brush 7 is connected to one end of the lead 2, and the lead 2 is placed in the lead groove 25. The other end of the lead 2 passes through the corresponding lead notch 19 on the outer shell 3 and is placed outside the outer shell 3. The lead groove 25 is filled with sealant 8.

[0039] In order to facilitate reliable installation of the first brush 5 and ensure smooth rotation of the collector ring 13 without increasing the axial size, the first brush 5 is installed on the collector ring 13 through rivets 4, and a concave clearance groove 21 is provided on the inner wall of the second end of the housing 3 at a position corresponding to the rivet 4.

[0040] In order to further ensure that the rivet 4 rotates smoothly with the collector ring 13 without increasing the axial dimension, the circumferential outer wall of the collector ring 13 close to the first annular groove 35 of the collector ring is concave to form a third annular groove 34 of the collector ring with an "L"-shaped radial cross-section, and the end of the rivet 4 is placed in the third annular groove 34 of the collector ring and the give way groove 21 at the same time.

[0041] In order to achieve better positioning and sealing effects, the inner wall surface of the part of the circumferential inner wall of the housing 3 placed in the first annular groove 35 of the collecting ring is provided with a concave first sealing groove 23, and the first sealing ring 6 is installed in the first sealing groove 23. The circumferential inner wall surface of the resistor body 14 is provided with a concave second sealing groove 26, and the second sealing ring 12 is installed in the second sealing groove 26.

[0042] In order to improve the lubrication property of the sealing ring and reduce friction, the first sealing ring 6 and the second sealing ring 12 are both polytetrafluoroethylene sealing rings.

[0043] In order to further reduce the product weight and facilitate rapid alignment of the zero position during application, the hole wall near the second end of the central through hole of the hollow shaft 10 is thinned toward the peripheral direction to form a hollow shaft countersunk hole 9, and the second end face of the outer shell 3 near the collecting ring 13 and the bottom surface of the hollow shaft countersunk hole 9 are respectively provided with corresponding zero position marking grooves 17 (which can also be zero position marking lines).

[0044] Figure 1-Figure 4 Also shown are four mounting lugs 1 provided on the housing 3 for mounting the sensor, and mounting holes 16 are provided on the mounting lugs 1; Fig. 9 and Fig.10Also shown are protruding mounting portions 33 disposed on opposite sides of the collector ring 13 and used for mounting the rivet 4. The protruding mounting portions 33 are provided with rivet through holes 32 for mounting the rivet 4. Since the present invention only installs one first brush 5, only one rivet through hole 32 is shown in the figure, but in order to facilitate processing and expanded application, two protruding mounting portions 33 are shown in the figure; in addition, the inner wall surface of the hollow shaft 10 is provided with two planes, which are convenient for achieving anti-rotation connection with the rotating parts of the detected equipment, and lubricating oil is filled in the small gaps between the housing 3 and the collector ring 13 and between the resistor 14 and the hollow shaft 10 to achieve better free rotation and sealing functions; these structures are all conventional adaptive structures.

[0045] like Figure 1-Figure 10 As shown, when used, the rotating part of the detected device is connected to the hollow shaft 10, and the housing 3 is installed on the detected device or other components. The rotating part of the detected device drives the hollow shaft 10 to rotate synchronously, and the hollow shaft 10 drives the collector ring 13 to rotate synchronously. The first brush 5 contacts and slides on the working belt 24 of the resistor 14 to generate a changing electrical signal, which is transmitted to the external signal processor through the conductive belt 39, the second brush 7 and the lead 2 to realize the angular displacement detection function.

[0046] The above embodiments are only preferred embodiments of the present invention and are not limitations of the technical solutions of the present invention. Any technical solution that can be implemented on the basis of the above embodiments without creative work should be deemed to fall within the scope of protection of the patent of the present invention.

Claims

1. An ultra-thin hollow shaft angular displacement sensor, comprising a housing, a resistor, a hollow shaft, a collector ring and a first brush, wherein the resistor is placed in the housing and connected to a first end of the housing, the first end of the hollow shaft passes through a central through hole of the resistor, a position near the first end of the circumferential outer wall of the hollow shaft is provided with a first hollow shaft annular groove whose outer wall is concave to form an "L"-shaped radial cross section, a portion of the resistor close to its circumferential inner wall is placed in the first hollow shaft annular groove, the second end of the hollow shaft passes through the central through hole of the collector ring and is connected to the collector ring, the collector ring is located in the second end of the housing, the first brush is mounted on the collector ring and contacts a working band on the resistor, Features: The circumferential outer wall of the hollow shaft near the second end protrudes toward the circumference to form a shaft convex ring, the part of the hollow shaft located between the second end and the shaft convex ring forms a second annular groove of the hollow shaft with a radial cross-section of "L" shape, the circumferential outer wall of the collecting ring near the second end of the hollow shaft is concave to form a first annular groove of the collecting ring with a radial cross-section of "L" shape, a section of the circumferential inner wall of the collecting ring away from the second end of the hollow shaft is concave to form a second annular groove of the collecting ring with a radial cross-section of "L" shape, the shaft convex ring is placed in the second annular groove of the collecting ring, the part of the collecting ring near the circumferential inner wall is placed in the second annular groove of the hollow shaft, and the part of the outer shell near the second end inner wall is placed in the first annular groove of the collecting ring.

2. The ultra-thin hollow shaft angular displacement sensor according to claim 1, Features: The resistor body has positioning bosses protruding toward the circumferential direction on opposite sides of the circumferential outer wall, and the shell has positioning grooves on opposite sides of the circumferential wall of the first end, and the two positioning bosses are respectively placed in the two positioning grooves, and a hollow shaft thread is provided on the groove wall corresponding to the circumferential inner wall of the collector ring in the second annular groove of the hollow shaft, and a collector ring thread is provided on the circumferential inner wall of the collector ring, and the hollow shaft thread and the collector ring thread do not contact each other and are connected by a sealant filled in the second annular groove of the hollow shaft.

3. The ultra-thin hollow shaft angular displacement sensor according to claim 2, Features: The circumferential outer wall of the resistor body is provided with a plurality of resistor body pin holes evenly distributed along the circumferential direction, the circumferential wall of the first end of the shell is provided with a plurality of shell pin holes evenly distributed along the circumferential direction, and a plurality of positioning pins pass through the plurality of shell pin holes and the plurality of resistor body pin holes respectively.

4. The ultra-thin hollow shaft angular displacement sensor according to claim 2, Features: The outer wall of one side of the shaft protrusion ring close to the resistor body is concave to form an annular positioning groove, and the annular positioning groove is filled with sealant that is tightly connected to the corresponding groove wall of the second annular groove of the collector ring.

5. The ultra-thin hollow shaft angular displacement sensor according to any one of claims 1 to 4, Features: A second brush is installed on the resistor body, and the second brush is insulated from the working belt on the resistor body. A conductive belt conductively connected to the first brush is provided on the side surface of the collector ring close to the resistor body, and the second brush contacts the conductive belt. A lead groove is provided on the side surface of the resistor body away from the first brush. The second brush is connected to one end of the lead wire, and the lead wire is placed in the lead groove. The other end of the lead wire passes through the corresponding lead notch on the outer shell and is placed outside the outer shell. The lead groove is filled with sealant.

6. The ultra-thin hollow shaft angular displacement sensor according to any one of claims 1 to 4, Features: The first brush is mounted on the collector ring through rivets, and a concave clearance groove is provided at a position corresponding to the rivet on the inner wall of the second end of the housing.

7. The ultra-thin hollow shaft angular displacement sensor according to claim 6, Features: The circumferential outer wall of the collector ring close to the first annular groove of the collector ring is concave to form a third annular groove of the collector ring with an "L"-shaped radial cross section, and the end of the rivet is placed in the third annular groove of the collector ring and the give way groove at the same time.

8. The ultra-thin hollow shaft angular displacement sensor according to any one of claims 1 to 4, Features: The inner wall surface of the portion of the circumferential inner wall of the shell that is placed in the first annular groove of the collector ring is provided with a concave first sealing groove, and a first sealing ring is installed in the first sealing groove. The circumferential inner wall surface of the resistor body is provided with a concave second sealing groove, and a second sealing ring is installed in the second sealing groove.

9. The ultra-thin hollow shaft angular displacement sensor according to claim 8, Features: The first sealing ring and the second sealing ring are both polytetrafluoroethylene sealing rings.

10. The ultra-thin hollow shaft angular displacement sensor according to any one of claims 1 to 4, Features: The hole wall near the second end of the central through hole of the hollow shaft is thinned toward the peripheral direction to form a hollow shaft countersunk hole, and the position near the collecting ring in the second end face of the shell and the bottom surface of the hollow shaft countersunk hole are respectively provided with corresponding zero position marking grooves or zero position marking lines.

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