A middle axle magnetic displacement torque sensor for electric bicycle
By using a magnetic displacement torque sensor, the Hall effect of helical tooth floating blocks and permanent magnets is utilized to detect the riding torque of electric bicycles, solving the problems of complex sensor structure and easy damage, and realizing accurate torque detection and long-life sensor.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- XIANGSU INTELLIGENT TECH (SUZHOU) CO LTD
- Filing Date
- 2025-05-26
- Publication Date
- 2026-06-02
Smart Images
Figure CN224311916U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of electric bicycle technology, and in particular to a magnetic displacement torque sensor for the central shaft of an electric bicycle. Background Technology
[0002] Torque sensors are a core component of electric bicycles, used to sense and measure the rider's riding torque, providing a basis for judging the power output of the electric drive unit. Therefore, the performance of torque sensors is extremely critical.
[0003] The commonly used measurement method is to set up a fixed sleeve, a sliding sleeve and a compression spring in conjunction with the central shaft. A magnetic ring is set on the sliding sleeve. The rotation of the magnetic ring is detected by a displacement sensor and the corresponding torque is converted into an electrical signal to achieve detection. However, the above structure is complicated, the actual displacement is small, and it is difficult to obtain reliable results.
[0004] The second measurement method involves attaching strain gauges to the central shaft. Changes in the torque of the central shaft will cause changes in the resistance of the strain gauges. The detection circuit can detect the magnitude of the corresponding strain gauge resistance and thus determine the magnitude of the torsion. However, the sensor with the above structure is prone to friction and wear, which reduces its lifespan. Therefore, we need to propose a new method to solve the above problems. Summary of the Invention
[0005] This invention overcomes the shortcomings of the prior art and provides a magnetic displacement torque sensor for the central shaft of an electric bicycle.
[0006] To achieve the above objectives, the technical solution adopted by this utility model is as follows: a magnetic displacement torque sensor for the bottom bracket of an electric bicycle, comprising: a pedal, a pedal shaft rotatably connected to the pedal, and a sensor body disposed at the end of the pedal shaft away from the pedal; the sensor body comprises: a pedal bottom bracket fixedly connected to the pedal shaft, and a fixing member wrapped around the outside of the pedal bottom bracket and rotatably connected to the pedal bottom bracket; a helical tooth floating block is fixedly connected to the pedal bottom bracket, and a helical member is engaged on the outside of the helical tooth floating block; a magnetic block is fixedly connected to the inside of the fixing member. A second magnetic block is fixedly connected to the end face of the spiral component facing the first magnetic block. The magnetic blocks one and two magnetic blocks have the same magnetic poles facing each other. When the pedal shaft rotates continuously, torque is transmitted to the spiral component through the helical tooth floating block, causing the second magnetic block on the spiral component to move axially along the pedal shaft towards the direction closer to the first magnetic block. According to the Hall effect, the magnetic blocks one and two, which are close to each other, generate voltage signals. When the pedal shaft stops rotating, according to the principle of like magnetic poles, the spiral component is driven to move back to its original position under the magnetic force of the magnetic blocks one and two magnetic blocks.
[0007] In a preferred embodiment of this utility model, the end faces of the first magnetic block and the second magnetic block are both planes, and the planes are parallel to each other.
[0008] In a preferred embodiment of this invention, both magnetic block one and magnetic block two are permanent magnets, and are made of neodymium iron boron permanent magnet material.
[0009] In a preferred embodiment of this utility model, the spiral component is made of alloy steel.
[0010] In a preferred embodiment of this utility model, a Hall effect element is installed on the inner side of the fixing member near the magnetic block one and the magnetic block two.
[0011] In a preferred embodiment of the present invention, a controller is further included, which is electrically connected to a Hall effect element and is used to control the forward movement of the electric-assisted bicycle.
[0012] In a preferred embodiment of this utility model, the meshing tooth profile of the helical floating block and the spiral component is an involute helical tooth, and the inclination angle of the meshing tooth profile of the helical floating block is 15°-45°.
[0013] In a preferred embodiment of this utility model, the distance between the first magnetic block and the second magnetic block is 0-0.5mm, and this distance is dynamically adjusted according to the change of the foot pedal input torque.
[0014] In a preferred embodiment of this invention, the voltage signal generated between the first magnetic block and the second magnetic block is 0-4V.
[0015] In a preferred embodiment of this utility model, the pedal axle and the fixing member are connected by at least two deep groove ball bearings located on both sides of the pedal axle.
[0016] This utility model solves the defects existing in the background technology, and has the following beneficial effects:
[0017] This invention utilizes a structural design where the foot pedal rotation drives the foot pedal shaft and the foot pedal central shaft to rotate. The helical tooth floating block transmits torque to the screw component, causing it to move axially. Simultaneously, the magnetic block two on the screw component and the magnetic block one inside the fixed component approach each other. Based on the Hall effect, the Hall element detects the change in magnetic field and generates a voltage signal. Compared to existing mechanical torque sensor technology, this application can accurately reflect torque changes, providing real-time information for the electric power assist control system and enabling automatic adjustment of the assist. Furthermore, the magnetic reset principle of the magnetic blocks one and two ensures the long service life of this application. Attached Figure Description
[0018] The present invention will be further described below with reference to the accompanying drawings and embodiments;
[0019] Figure 1 This is a perspective structural diagram of a preferred embodiment of the present invention;
[0020] Figure 2 This is a cross-sectional view of a preferred embodiment of the present invention;
[0021] In the diagram: 1. Foot pedal; 2. Foot pedal shaft; 3. Sensor body; 31. Foot pedal central shaft; 32. Fixing component; 321. Magnetic block one; 33. Helical tooth floating block; 34. Helical component; 341. Magnetic block two; 35. Hall effect element; 36. Deep groove ball bearing. Detailed Implementation
[0022] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. These drawings are simplified schematic diagrams, which are only used to illustrate the basic structure of the present invention in a schematic manner, and therefore only show the components related to the present invention.
[0023] like Figure 1 , Figure 2 As shown, a magnetic displacement torque sensor for the bottom bracket of an electric bicycle includes: a pedal 1, a pedal shaft 2 rotatably connected to the pedal 1, and a sensor body 3 disposed at the end of the pedal shaft 2 away from the pedal 1; specifically, the sensor body 3 includes: a pedal bottom shaft 31 welded and fixed to the pedal shaft 2, and a fixing member 32 wrapped around the outside of the pedal bottom shaft 31 and rotatably connected to the pedal bottom shaft 31; generally, the fixing member 32 is fixed to the bicycle frame with a nut, thereby fixing the sensor body 3 to the electric bicycle.
[0024] Furthermore, a helical toothed floating block 33 is integrally provided on the pedal central shaft 31. A helical component 34 is engaged with the helical toothed floating block 33 on the outer side. A magnetic block 321 is fixedly connected to the inner side of the fixing component 32. A magnetic block 341 is fixedly connected to the end face of the helical component 34 facing the magnetic block 321. The magnetic blocks 321 and 341 are arranged with their magnetic poles of the same polarity opposite each other. In the above structure, when the pedal central shaft 31 rotates continuously, the helical toothed floating block 33 transmits torque to the helical component 34, causing the magnetic block 341 on the helical component 34 to move axially along the pedal central shaft 31 in a direction closer to the magnetic block 321. According to the Hall effect, they move closer to each other. The magnetic blocks 321 and 341 generate voltage signals. When the pedal shaft 31 stops rotating, according to the principle of like poles, the magnetic force of the magnetic blocks 321 and 341 drives the screw 34 to move back to its original position. This magnetic displacement-based detection method can accurately convert torque changes into electrical signals. Compared with the traditional mechanical torque detection method, it has higher detection accuracy. The distance between the magnetic blocks 321 and 341 is dynamically adjusted according to the pedal input torque, which can keenly capture subtle changes in torque and provide more accurate torque information for the electric assist control system of electric bicycles.
[0025] Furthermore, the end faces of magnetic block 321 and magnetic block 341 are both planar and parallel to each other. Both magnetic block 321 and magnetic block 341 are permanent magnets, preferably made of neodymium iron boron permanent magnet material. This material has strong magnetic properties and stability. In the complex electromagnetic environment of electric bicycles, neodymium iron boron permanent magnet material can maintain relatively stable magnetic field characteristics.
[0026] Furthermore, the spiral component 34 is made of alloy steel, which has high strength and wear resistance, enabling it to resist wear and deformation during long-term rotation and torque transmission of the pedal shaft 2. Compared with some ordinary materials, the alloy steel spiral component 34 has a longer service life, ensuring stable operation of the sensor throughout the entire lifespan of the electric bicycle.
[0027] Furthermore, a Hall effect element 35 is installed on the inner side of the fixing member 32 near the magnetic block 321 and the magnetic block 341. This element can sense the changes in the magnetic field caused by the change in the distance between the magnetic blocks in real time, thereby generating a corresponding voltage signal in a timely manner. This real-time feedback characteristic allows the electric assist control system of the electric bicycle to quickly adjust the amount of assistance according to the current riding torque, improving riding comfort and efficiency.
[0028] Furthermore, it also includes a controller, which is electrically connected to the Hall effect element 35, for controlling the forward movement of the electric-assisted bicycle.
[0029] Furthermore, the meshing tooth profile of the helical floating block 33 and the helical component 34 is an involute helical tooth, and the inclination angle of the meshing tooth profile of the helical floating block 33 is 15°-45°, ensuring that the rotation of the foot pedal central shaft 31 can drive the meshing helical component 34 to move through the helical floating block 33.
[0030] Specifically, the distance between magnetic block 321 and magnetic block 341 is 0-0.5mm. This distance is dynamically adjusted according to the change of pedal input torque. The distance range can be optimized according to the controller algorithm to ensure more accurate torque information. The voltage signal generated between magnetic block 321 and magnetic block 341 is 0-4V. The voltage signal range is wide and can correspond to different magnitudes of torque input. From the slight pedaling force when riding on flat roads to the heavy pedaling force when climbing hills, all can be reflected within this voltage range, so that the sensor can adapt to the needs of electric bicycles for different torque detection under various road conditions.
[0031] Furthermore, the pedal axle 31 and the fixing member 32 are connected by at least two deep groove ball bearings 36 located on both sides of the pedal axle 31, thereby reducing the friction between the pedal axle 31 and the fixing member 32 when the pedal axle 31 rotates.
[0032] Working principle: When the rider presses the pedal 1, the pedal 1 drives the pedal shaft 2 to rotate. Since the pedal shaft 31 is welded and fixed to the pedal shaft 2, the rotation of the pedal shaft 2 causes the pedal shaft 31 to rotate as well. The helical tooth floating block 33 integrated on the pedal shaft 31 meshes with the helical component 34. The meshing teeth of the helical tooth floating block 33 are involute helical teeth with an inclination angle of 15°-45°. This design ensures that when the pedal shaft 31 rotates, the torque can be effectively transmitted to the helical component 34 through the helical tooth floating block 33, causing the helical component 34 to move axially along the pedal shaft 31. The end face of the helical component 34 facing the magnetic block 321 is fixedly connected to the magnetic block 34, while the inner side of the fixing component 32 is fixedly connected to the magnetic block 321. The end faces of the magnetic block 321 and the magnetic block 341 are both flat and parallel to each other. Both are permanent magnets made of neodymium iron boron permanent magnet material and are of the same polarity. With the axial displacement of the screw 34, the second magnetic block 341 moves closer to the first magnetic block 321. According to the Hall effect, the Hall effect element 35 installed on the inner side of the fixing member 32 near the first magnetic block 321 and the second magnetic block 341 can sense the change in magnetic field caused by the change in distance between the magnetic blocks and generate a corresponding voltage signal in time. This voltage signal is 0-4V, which can correspond to different magnitudes of torque input. From the slight pedaling force when riding on a flat road to the heavy pedaling force when climbing a hill, it can all be reflected within this voltage range, thus providing real-time and accurate torque information for the electric assist control system of the electric bicycle. When the rider stops pedaling and the pedal shaft 31 stops rotating, based on the principle of like poles, the magnetic force between the first magnetic block 321 and the second magnetic block 341 will drive the screw 34 to move back to its original position and return to the initial state, waiting for the next torque input and detection.
[0033] Throughout the operation, the pedal axle 31 and the fixing member 32 are connected by at least two deep groove ball bearings 36 located on both sides of the pedal axle 31. This reduces the friction between the pedal axle 31 and the fixing member 32 during rotation, ensuring smooth rotation and sensor sensitivity. The controller is electrically connected to the Hall effect element 35, enabling timely control of the electric-assisted bicycle's forward movement based on the voltage signal generated by the Hall effect element 35. It automatically adjusts the assist level according to different road conditions and the rider's pedaling torque, improving riding comfort and efficiency. The distance between magnetic block 1 321 and magnetic block 2 341 is 0-0.5mm, and this distance dynamically adjusts with changes in pedal input torque. The distance range can be optimized according to the controller's algorithm, further ensuring more accurate torque information. Compared to existing technologies, the torque sensor of this application provides more accurate torque information and has a longer service life.
[0034] Based on the preferred embodiments of this utility model described above, those skilled in the art can make various changes and modifications without departing from the technical concept of this utility model. The technical scope of this utility model is not limited to the contents of the specification, but must be determined according to the scope of the claims.
Claims
1. A magnetic displacement torque sensor for the bottom bracket of an electric bicycle, characterized in that, include: Foot pedal (1), foot pedal shaft (2) rotatably connected to the foot pedal (1), and sensor body (3) disposed at the end of the foot pedal shaft (2) away from the foot pedal (1); The sensor body (3) includes: a pedal shaft (31) fixedly connected to the pedal shaft (2), and a fixing member (32) wrapped around the outside of the pedal shaft (31) and rotatably connected to the pedal shaft (31); A helical tooth floating block (33) is fixedly connected to the foot pedal central shaft (31). A helical tooth floating block (33) meshes with a helical component (34) on the outside. A magnetic block one (321) is fixedly connected to the inside of the fixing component (32). A magnetic block two (341) is fixedly connected to the end face of the helical component (34) facing the magnetic block one (321). The magnetic blocks one (321) and the magnetic blocks two (341) are arranged with the same magnetic poles facing each other. When the pedal shaft (31) rotates continuously, the torque is transmitted to the screw (34) through the helical floating block (33), causing the magnetic block two (341) on the screw (34) to move axially along the pedal shaft (31) towards the direction of magnetic block one (321). According to the Hall effect, the magnetic block one (321) and magnetic block two (341) that are close to each other generate voltage signals. When the foot pedal shaft (31) stops rotating, according to the principle of magnetic poles, the magnetic force of the magnetic block one (321) and the magnetic block two (341) drives the spiral component (34) to move back to its original position.
2. The magnetic displacement torque sensor for the central shaft of an electric bicycle according to claim 1, characterized in that: The end faces of the first magnetic block (321) and the second magnetic block (341) are both planes, and the planes are parallel to each other.
3. The magnetic displacement torque sensor for the central shaft of an electric bicycle according to claim 1, characterized in that: Both magnetic block one (321) and magnetic block two (341) are permanent magnets and are made of neodymium iron boron permanent magnet material.
4. A magnetic displacement torque sensor for the central shaft of an electric bicycle according to claim 1, characterized in that: The spiral component (34) is made of alloy steel.
5. A magnetic displacement torque sensor for the central shaft of an electric bicycle according to claim 1, characterized in that: A Hall effect element (35) is installed on the inner side of the fixing member (32) near the magnetic block one (321) and magnetic block two (341).
6. A magnetic displacement torque sensor for the bottom bracket of an electric bicycle according to claim 1, characterized in that, It also includes a controller electrically connected to a Hall effect element (35) for controlling the forward movement of the electric-assisted bicycle.
7. A magnetic displacement torque sensor for the central shaft of an electric bicycle according to claim 1, characterized in that: The meshing tooth profile of the helical floating block (33) and the spiral component (34) is an involute helical tooth, and the inclination angle of the meshing tooth profile of the helical floating block (33) is 15°-45°.
8. A magnetic displacement torque sensor for the central shaft of an electric bicycle according to claim 1, characterized in that: The distance between the first magnetic block (321) and the second magnetic block (341) is 0-0.5mm, and this distance is dynamically adjusted according to the change of the foot pedal input torque.
9. A magnetic displacement torque sensor for the central shaft of an electric bicycle according to claim 1, characterized in that: The voltage signal generated between the first magnetic block (321) and the second magnetic block (341) is 0-4V.
10. A magnetic displacement torque sensor for the central shaft of an electric bicycle according to claim 1, characterized in that: The pedal axle (31) and the fixing member (32) are connected by at least two deep groove ball bearings (36) located on both sides of the pedal axle (31).