A flux type torque sensor

Abstract

The present invention relates to the technical field of sensors, and specifically relates to a magnetic flux type torque sensor. The present invention adopts a structure in which a torque sleeve, an isolation sleeve, a coil assembly and a circuit board are sequentially arranged on a central axis. A shielding structure is arranged on the torque sleeve, and a through hole matching the shielding structure is arranged on the isolation sleeve. The torque sleeve rotates with the central axis to drive the output part to rotate, and the torque sleeve undergoes elastic deformation to change the shielding area between the torque sleeve and the isolation sleeve, thereby changing the magnetic flux rate. The coil assembly detects the change in the magnetic flux rate under the shielding area to measure the change in torque, improving the detection accuracy of the magnetic flux type torque sensor. Moreover, the torque sleeve, the isolation sleeve and the coil assembly can all be sequentially sleeved on the central axis, with a simple structure and easy installation. The connection mode with the central axis is firm, and there will be no problem of falling off, improving the stability and reliability of the magnetic flux type torque sensor.

Description

Technical Field

[0001] The present invention relates to the technical field of sensors, and particularly to a magnetic flux type torque sensor. Background Art

[0002] A sensor (English name: transducer / sensor) is a detection device that can sense the information to be measured and transform the sensed information into an electrical signal or other required form of information output according to a certain rule to meet the requirements of information transmission, processing, storage, display, recording, and control.

[0003] An assisted bicycle is a new type of two-wheeled vehicle, belonging to a kind of bicycle. It uses a battery as an auxiliary power source, is equipped with a motor, and has a power assist system, and can realize a new type of transportation vehicle that integrates human-powered riding and motor-assisted driving. A torque sensor is the core component for the electric assist system of an assisted bicycle to understand the intention of the rider. Due to the existence of the torque sensor, during the riding process, the motor output power of the electric bicycle can be adjusted according to the measured torque, improving the riding comfort.

[0004] At present, more and more assisted bicycles adopt a torque sensor installed on the bottom bracket. The common structure is to paste strain gauges on the bottom bracket or the sleeve connected to the bottom bracket. The torque of pedaling is sensed by the strain gauges, and after signal processing, a voltage signal is output, and then the output power of the motor is controlled. Such a structure has problems of insufficient detection accuracy, difficult installation, and low stability and reliability. Summary of the Invention

[0005] In order to solve the above problems existing in the prior art, the present invention provides a magnetic flux type torque sensor.

[0006] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0007] A magnetic flux type torque sensor is installed on the bottom bracket and includes: a torque sleeve, one end of which is fixedly connected to the bottom bracket and rotates with the bottom bracket, and the other end is connected to an output part; an isolation sleeve, sleeved on the torque sleeve and fixedly connected to the torque sleeve at one end; a coil assembly, sleeved on the isolation sleeve; a circuit board, electrically connected to the coil assembly; wherein, a shielding structure is arranged on the outer surface of the torque sleeve, a through hole matching with the shielding structure is arranged on the isolation sleeve, the bottom bracket drives the torque sleeve to rotate, and the torque sleeve generates elastic deformation to change the shielding area between the through hole and the shielding structure.

[0008] Further, there are several shielding structures and they are arranged on the outer surface of the torque sleeve along the circumferential direction.

[0009] Further, there are several through holes, which are correspondingly arranged on the side wall of the isolation sleeve and correspond to several of the shielding structures.

[0010] Further, the shielding structure is a groove or a protrusion provided on the outer surface of the torsion sleeve.

[0011] Further, the groove or the protrusion is waist-shaped.

[0012] Further, the shielding structure and the through holes are arranged alternately.

[0013] Further, the through holes are distributed in a mesh pattern on the side wall of the isolation sleeve.

[0014] Further, a magnetic isolation sleeve is provided between the coil assembly and the circuit board.

[0015] Further, the coil assembly includes a coil bracket and at least one set of induction coils, and the induction coils are wound on the coil bracket at positions corresponding to the through holes.

[0016] Further, a circuit board bracket is sleeved on the coil assembly, the circuit board is mounted on the circuit board bracket, and the circuit board bracket is connected to the torsion sleeve through a rolling bearing.

[0017] Further, a Hall sensor is provided on the circuit board bracket, and the Hall sensor is used to sense the rotation speed of the central shaft.

[0018] The present invention mainly has the following beneficial effects:

[0019] The flux-type torsion sensor of the present invention adopts a structure in which a torsion sleeve, an isolation sleeve, a coil assembly, and a circuit board are sequentially arranged on a central shaft. A shielding structure is provided on the torsion sleeve, and through holes matching the shielding structure are provided on the isolation sleeve. When one end of the torsion sleeve meshes with the output part, the central shaft drives the output part to rotate through the torsion sleeve, and the torsion sleeve undergoes elastic deformation to change the shielding area between the torsion sleeve and the isolation sleeve, thereby changing the magnetic flux rate. The coil assembly detects the change in the magnetic flux rate under the shielding area to measure the change in torsion, improving the detection accuracy of the flux-type torsion sensor. Moreover, the torsion sleeve, the isolation sleeve, and the coil assembly can all be sequentially sleeved on the central shaft, with a simple structure and easy installation. The connection method with the central shaft is firm, and there will be no problem of falling off, improving the stability and reliability of the flux-type torsion sensor. Description of the Drawings

[0020] Figure 1 is an assembly schematic diagram of the flux-type torsion sensor according to an embodiment of the present invention;

[0021] Figure 2It is a schematic structural diagram of the magnetic flux type torque sensor according to an embodiment of the present invention;

[0022] Figure 3 It is a schematic cross-sectional view of the magnetic flux type torque sensor according to an embodiment of the present invention. Specific embodiments

[0023] In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0024] Refer to Figures 1 to 3 A magnetic flux type torque sensor as shown. The magnetic flux type torque sensor is installed on the central shaft 100. It includes a torque sleeve 200 with one end fixed to the central shaft 100. An isolation sleeve 300 is sleeved on the torque sleeve 200, and a coil assembly 400 is also sleeved on the isolation sleeve 300. The coil assembly 400 is connected to a circuit board 500. Specifically, the central shaft 100 is connected to the pedal directly or indirectly. One end of the torque sleeve 200 is connected to the central shaft 100 by a spline and rotates with the central shaft 100. The other end is connected with an output part 101. It should be noted that in this embodiment, the output part 101 can be a shaft-like part or a gear-like part, and the torque sleeve 200 and the output part 101 can be connected by a one-way device. The one-way device can be a ratchet or a one-way clutch. The one-way clutch can adopt a commonly used structure in the industry and will not be elaborated in this technical solution; One end of the isolation sleeve 300 is fixed to the torque sleeve 200, and the other end is suspended. A shielding structure 201 is also arranged on the outer surface of the torque sleeve 200, and a through hole 301 matching the shielding structure 201 is also arranged on the isolation sleeve 300. When a person steps on the pedal, the central shaft 100 is driven to rotate. Since the torque is transmitted between the central shaft 100 and the output part 101 through the torque sleeve 200, the torque sleeve 200 is deformed at this time, thereby changing the shielding area between the torque sleeve 200 and the isolation sleeve 300, that is, changing the magnetic flux rate. The coil assembly 400 detects the change of the magnetic flux rate under the shielding area and forms an electrical signal and transmits it to the circuit board 500. After receiving the electrical signal, the circuit board 500 measures the change of the torque after processing and conversion, improving the detection accuracy of the magnetic flux type torque sensor; And the torque sleeve 200, the isolation sleeve 300, and the coil assembly 400 can be sleeved on the central shaft 100 in sequence. The structure is simple and easy to install, and the connection method with the central shaft 100 is firm, and there will be no problem of falling off, improving the stability and reliability of the magnetic flux type torque sensor.

[0025] In some embodiments, there are several of the shielding structures 201, which are circumferentially arranged on the outer surface of the torsion sleeve 200. Specifically, the torsion sleeve 200 is cylindrical, and the shielding structures 201 are arranged on the outer surface of the cylindrical torsion sleeve 200. When the central axis 100 drives the output part 101 to rotate, torque is transmitted through the torsion sleeve 200, causing the torsion sleeve 200 to undergo a slight deformation, which is usually an elastic deformation. The slight deformation generated on the torsion sleeve 200 can cause a change in the magnetic flux rate between the torsion sleeve 200 and the isolation sleeve 300. The change in the magnetic flux rate is detected by the coil assembly 400, and then the change is processed by the circuit board 500 to obtain the change in torque.

[0026] In some embodiments, there are several through holes 301, which are correspondingly arranged on the side wall of the isolation sleeve 300 and correspond to several of the shielding structures 201. By arranging several shielding structures 201 in cooperation with several through holes 301, the detection accuracy can be improved, that is, the change in the shielding area between the torsion sleeve 200 and the isolation sleeve 300 can be refined, and then the change in the magnetic flux rate can be accurately detected; in some other embodiments, the through holes 301 are arranged in a mesh pattern, and the purpose is to further improve the detection accuracy.

[0027] In some embodiments, the shielding structures 201 and the through holes 301 are arranged in an alternating manner. The purpose is that the aperture of the through hole 301 can be greater than, less than, or equal to the maximum size of the shielding structure 201. This can ensure that when the torsion sleeve 200 undergoes elastic deformation, the shielding area between the boundary of the shielding structure 201 and the through hole 301 changes, preventing the through hole 301 from always being within the shielding structure 201 or the shielding structure 201 from always being within the through hole 301 without a change in the shielding area. That is to say, the boundary of the through hole 301 needs to be able to project into the shielding structure 201 and / or the boundary of the shielding structure 201 needs to be able to project into the through hole 301, so as to ensure that when the torsion sleeve 200 undergoes elastic deformation, the overlapping area between the isolation sleeve 300 and the shielding structure 201 changes, that is, the shielding area changes, thereby causing a change in the magnetic flux rate.

[0028] In some embodiments, referring to Figure 1 As shown, the shielding structure 201 is a groove or a protrusion provided on the outer surface of the torsion sleeve 200. In this embodiment, the groove is taken as an example, and the groove is waist-shaped. The purpose is to ensure that the distance between the shielding structure 201 and the isolation sleeve 300 and the distance between the outer surface of the torsion sleeve 200 and the isolation sleeve 300 are different, so as to cause a change in the magnetic flux rate when the torsion sleeve 200 deforms, and the depth of the groove or the height of the protrusion can be set according to the actual situation.

[0029] In some embodiments, referring toFigure 1 As shown in Figure 3 Figure 3 , a magnetic isolation sleeve 600 is provided between the coil assembly 400 and the circuit board 500, aiming to prevent the magnetic field from spreading out and affecting the circuit board 500.

[0030] In some embodiments, the coil assembly 400 includes a coil bracket and at least one set of induction coils wound around the coil bracket. Specifically, the induction coils are wound around the coil bracket at positions corresponding to the through holes 301, aiming to further improve the detection accuracy, ensure that the induction coils can accurately detect the change in magnetic flux rate, and then convert it into an electrical signal and send it to the circuit board 500.

[0031] In some embodiments, a circuit board bracket 700 is sleeved on the coil assembly 400, the circuit board 500 is mounted on the circuit board bracket 700, and the circuit board bracket 700 is connected to the torsion sleeve 200 through a rolling bearing 800. That is to say, when the central shaft 100 rotates, the torsion sleeve 200, the isolation sleeve 300, and the coil assembly 400 rotate with the central shaft 100. A relative rotation occurs between the torsion sleeve 200 and the isolation sleeve 300 due to the elastic deformation of the torsion sleeve 200, resulting in a change in the shielding area. The coil assembly 400 detects the change in magnetic flux rate caused by the change in the shielding area. The magnetic isolation sleeve 600 can rotate with the torsion sleeve 200 or not. The circuit board bracket 700 is connected to the torsion sleeve 200 through a rolling bearing 800, so that the circuit board bracket 700 does not rotate with the torsion sleeve 200, ensuring the stability and reliability of the magnetic flux type torsion sensor.

[0032] In some embodiments, referring to Figure 1 As shown in Figure 2 Figure 2 , a Hall sensor 900 is provided on the circuit board bracket 700, and this Hall sensor 900 is used to sense the rotation speed of the central shaft 100. Specifically, since the torsion sleeve 200 rotates synchronously with the central shaft 100, the rotation speed of the central shaft 100 can be measured by detecting the rotation speed of the torsion sleeve 200 through the Hall sensor 900. In this embodiment, the Hall sensor 900 can adopt conventional models and specifications on the market, and the specific structure of the Hall sensor 900 will not be elaborated here.

[0033] It should be noted that the torsion sleeve 200 described in all the above embodiments can be made of materials with high magnetic permeability, such as iron or iron alloy.

[0034] The above is the preferred implementation manner of the present invention. It should be pointed out that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements are also regarded as the protection scope of the present invention.

Claims

1. A magnetic flux type torque sensor is installed on the central axis, characterized in that, Comprising: A torque sleeve that can rotate with the central shaft, one end fixedly connected to the central shaft, and the other end connected to the output part; An isolation sleeve sleeved on the torque sleeve and fixedly connected to the torque sleeve at one end; A coil assembly sleeved on the isolation sleeve; A circuit board electrically connected to the coil assembly; Wherein, a shielding structure is provided on the outer surface of the torque sleeve, and a through hole matching the shielding structure is provided on the isolation sleeve. The torque sleeve rotates with the central shaft and undergoes elastic deformation to change the shielding area between the torque sleeve and the isolation sleeve; There are several of the shielding structures and they are arranged circumferentially on the outer surface of the torque sleeve; The shielding structure and the through hole are arranged in an alternating manner.

2. A flux type torque sensor according to claim 1, wherein There are several of the through holes and they are correspondingly arranged on the side wall of the isolation sleeve in correspondence with several of the shielding structures.

3. A flux-type torque sensor according to claim 1, characterized in that, The shielding structure is a groove or a protrusion provided on the outer surface of the torque sleeve.

4. A flux type torque sensor according to any one of claims 1 to 3, characterized in that The through holes are distributed in a mesh pattern on the side wall of the isolation sleeve.

5. A flux type torque sensor according to claim 1, characterized in that, A magnetic isolation sleeve is provided between the coil assembly and the circuit board.

6. A flux type torque sensor according to claim 1, characterized in that, The coil assembly includes a coil bracket and at least one set of induction coils, and the induction coils are wound on the coil bracket at positions corresponding to the through holes.

7. A flux type torque sensor according to claim 1, wherein, A circuit board bracket is sleeved on the coil assembly, the circuit board is mounted on the circuit board bracket, and the circuit board bracket is connected to the torque sleeve through a rolling bearing.

8. A flux type torque sensor according to claim 7, characterized in that, A Hall sensor is provided on the circuit board bracket, and the Hall sensor is used to sense the rotational speed of the central shaft.

Images