Integrated crank middle shaft press-in type torque sensor structure

Abstract

The utility model relates to the technical field of electric power-assisted bicycles, in particular to an integrated crank middle shaft press-in type torque sensor structure. The device comprises an integrated crank middle shaft assembly, a first shaft sleeve assembly, a second shaft sleeve assembly, a detection assembly and a magnetic ring, the integrated crank middle shaft assembly comprises a hollow shaft, the first shaft sleeve assembly, the detection assembly and the second shaft sleeve assembly are sequentially assembled into a whole in a butt joint mode, and the hollow shaft penetrates through the first shaft sleeve assembly, the detection assembly and the second shaft sleeve assembly. The hollow shaft rotates relative to the detection assembly, the magnetic ring synchronously rotates along with the hollow shaft, and the detection assembly identifies magnetic field changes between the magnetic ring and the hollow shaft. According to the structure, the shaft sleeve and the hollow shaft are pressed on the joint face of the bearing inner ring together, torque and stress are transmitted through cooperation and friction force between the hollow shaft and the shaft sleeve, signals are detected through the detection assembly, and the structure is simple in principle, convenient to operate and high in assembly speed.

Description

Technical Field

[0001] The utility model relates to the technical field of electric assist bicycles, and particularly relates to a torque sensor structure with an integrated crank bottom bracket press-in type. Background Art

[0002] The torque sensors of existing electric assist bicycles adopt a threaded screwing type. The bottom bracket tube needs to be threaded, the installation process is relatively complex, the operation requirements are high, the assembly speed is slow, the weight is relatively large, and the frame design is limited by a smaller diameter and a narrower width. At the same time, it is not applicable to high-end models such as carbon fiber bicycles, and is currently mainly used for traditional bicycles and low-end sports bicycles.

[0003] Due to the uniqueness of the press-in type bottom bracket itself, there are certain limitations on the torque sensor. At present, most press-in type torques measure the torque by detecting the deformation of the chainring, and the measurement of the shaft deformation cannot be realized, and the signal output of the product is not ideal. Content of the Utility Model

[0004] The utility model provides a torque sensor structure with an integrated crank bottom bracket press-in type, aiming to solve the problems existing in the torque sensors of existing electric assist bicycles.

[0005] The utility model provides a torque sensor structure with an integrated crank bottom bracket press-in type, which includes an integrated crank bottom bracket assembly, a first bushing assembly, a second bushing assembly, a detection assembly, and a magnetic ring. The integrated crank bottom bracket assembly includes a hollow shaft. The first bushing assembly, the detection assembly, and the second bushing assembly are sequentially butt-assembled into one body. The hollow shaft passes through the first bushing assembly, the detection assembly, and the second bushing assembly. The hollow shaft rotates relative to the detection assembly. The magnetic ring rotates synchronously with the hollow shaft. The detection assembly identifies the magnetic field change between the magnetic ring and the hollow shaft.

[0006] As a further improvement of the utility model, the first bushing assembly includes a first bushing, a first bearing, and a first dust cover. The outer ring of the first bearing is fixed to the first bushing, and the first dust cover is fixed to the inner ring of the first bearing. The second bushing assembly includes a second bushing, a second bearing, and a second dust cover. The outer ring of the second bearing is fixed to the second bushing, and the second dust cover is fixed to the inner ring of the second bearing. The first dust cover and the second dust cover are fixed on the hollow shaft. The detection assembly is respectively connected to the first bushing and the second bushing.

[0007] As a further improvement of the utility model, the torque sensor structure with an integrated crank bottom bracket press-in type further includes a reduced diameter ring. The reduced diameter ring is connected to one end of the first dust cover and / or the second dust cover. The magnetic ring is connected to the reduced diameter ring.

[0008] As a further improvement of the present utility model, the detection component includes a cage, a PCBA board, and a wire harness. Both ends of the cage are fixedly connected to a first shaft sleeve and a second shaft sleeve respectively. The PCBA board is connected to the cage. A magnetic sensor and an acceleration sensor are connected to the PCBA board. The wire harness is connected to the PCBA board. The PCBA board detects the signal of the magnetic ring and outputs it through the wire harness.

[0009] As a further improvement of the present utility model, the outside of the PCBA board is covered with injection molding plastic.

[0010] As a further improvement of the present utility model, the detection component further includes a sealing ring. Sealing grooves are provided at both ends of the cage. The sealing ring is connected in the sealing grooves. The cage is connected to the inner walls of the first shaft sleeve and / or the second shaft sleeve through the sealing ring.

[0011] As a further improvement of the present utility model, the integrated crank bottom bracket assembly further includes a left crank and a right crank. Both ends of the hollow shaft are respectively connected to the left crank and the right crank. The left crank and the right crank form an angle of 180°.

[0012] As a further improvement of the present utility model, the integrated crank bottom bracket assembly further includes a chainring and crank bolts. One end of the hollow shaft is press-fitted with the right crank and the chainring as a whole. The left crank is fastened to the other end of the hollow shaft through the crank bolts.

[0013] As a further improvement of the present utility model, the material of the hollow shaft is a magnetostrictive material.

[0014] The beneficial effects of the present utility model are as follows: In this structure, the shaft sleeve and the hollow shaft are pressed together on the joint surface of the inner ring of the bearing. The cooperation and frictional force between the hollow shaft and the shaft sleeve are used to transmit torque and force, and the detection component is used to detect signals. Its structural principle is simple, the operation is convenient, and the assembly speed is fast. Description of the Drawings

[0015] Figure 1 is the overall structure diagram of the torque sensor structure of the integrated crank bottom bracket press-in type of the present utility model;

[0016] Figure 2 is the structure diagram of the first shaft sleeve assembly of the present utility model;

[0017] Figure 3 is the structure diagram of the second shaft sleeve assembly of the present utility model;

[0018] Figure 4 is the structure diagram of the detection component of the present utility model;

[0019] Figure 5 is the structure diagram of the integrated crank bottom bracket assembly of the present utility model;

[0020] Figure 6 It is a cross-sectional view of the connection structure of the first bushing assembly, the second bushing assembly, and the detection assembly in the present utility model. Detailed implementation manners

[0021] In order to make the purpose, technical solutions and advantages of the present utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments.

[0022] As Figure 1 shown, the present utility model provides a torque sensor structure of an integrated crank bottom bracket press-in type, including an integrated crank bottom bracket assembly 1, a first bushing assembly 2, a second bushing assembly 3, a detection assembly 4, and a magnetic ring 5. The integrated crank bottom bracket assembly 1 includes a hollow shaft 11. The first bushing assembly 2, the detection assembly 4, and the second bushing assembly 3 are sequentially butt-jointed and assembled into one body. The hollow shaft 11 passes through the first bushing assembly 2, the detection assembly 4, and the second bushing assembly 3. The hollow shaft 11 rotates relative to the detection assembly 4, and the magnetic ring 5 rotates synchronously with the hollow shaft 11. The detection assembly 4 identifies the magnetic field change between the magnetic ring 5 and the hollow shaft 11.

[0023] The present utility model is a torque sensor product of an integrated crank bottom bracket press-in type applied to an electric assist bicycle, which includes an integrated crank bottom bracket assembly 1, a first bushing assembly 2, a second bushing assembly 3, a detection assembly 4, etc. The first bushing assembly 2 and the second bushing assembly 3 are respectively press-fitted at both ends of the bottom bracket of the bicycle. The integrated crank bottom bracket assembly 1 is press-fitted into the bushing assembly. The detection assembly 4 is located between the two bushing assemblies for detecting the deformation and rotation of the shaft. Both ends of the integrated crank bottom bracket assembly 1 are respectively connected to the left pedal and the right pedal. When the hollow shaft 11 of the integrated crank bottom bracket assembly 1 is subjected to a crank torque, it deforms and rotates. The detection assembly 4 detects the torque signal and the speed signal and then outputs them externally. This structure is assembled into the bottom bracket of the frame by a press-in method, which reduces the installation time and improves the installation efficiency compared with the threaded screw-in type product.

[0024] The existing torque detection methods all cover a layer of strain gauges on the outer surface of the hollow shaft. The integrated bottom bracket design is very simple, and the hollow shaft itself is a component that undergoes torsional deformation. However, the detection principle of the PCBA board 42 assembly in the present utility model is different from the existing ones. The PCBA board 42 assembly detects the magnetic field change on the surface of the deformation part. Based on the electro-magnetic principle, it judges and feeds back in the form of "electricity" when the magnetic field changes.

[0025] As Figure 2 and Figure 3As shown in the figure, the first bushing assembly 2 includes a first bushing 21, a first bearing 22, and a first dust cover 23. The outer ring of the first bearing 22 is fixed to the first bushing 21, and the first dust cover 23 is fixed to the inner ring of the first bearing 22. The second bushing assembly 3 includes a second bushing 31, a second bearing 32, and a second dust cover 33. The outer ring of the second bearing 32 is fixed to the second bushing 31, and the second dust cover 33 is fixed to the inner ring of the second bearing 32. The first dust cover 23 and the second dust cover 33 are fixed to the hollow shaft 11, and the detection assembly 4 is respectively connected to the first bushing 21 and the second bushing 31.

[0026] During assembly, the first bearing 22 is press-fitted into the first bushing 21, and the first dust cover 23 is installed into the inner ring of the first bearing 22 so that the first dust cover 23 can rotate relative to the first bushing 21. The second bearing 32 is press-fitted into the second bushing 31, and the second dust cover 33 is installed into the inner ring of the second bearing 32 so that the second dust cover 33 can rotate relative to the second bushing 31. Finally, the first dust cover 23 and the second dust cover 33 rotate synchronously with the hollow shaft 11, while the detection assembly 4 is fixed and does not rotate with the hollow shaft 11. The detection assembly 4 detects the magnetic field change formed by the deformation generated when the hollow shaft 11 rotates.

[0027] The torque sensor structure of the integrated crank bottom bracket press-in type further includes a reducing ring 6. The reducing ring 6 is connected to one end of the first dust cover 23 and / or the second dust cover 33, and the magnetic ring 5 is connected to the reducing ring 6. The reducing ring 6 is assembled at the smaller-diameter end of the outer diameter of the first dust cover 23 and / or the second dust cover 33, and the magnetic ring 5 is assembled on the reducing ring 6. The magnetic ring 5 can rotate together with the reducing ring 6, the dust cover, and the inner ring of the bearing. The reducing ring 6 functions to limit and fix the magnetic ring 5. As Figure 3 shown, in this embodiment, preferably, the magnetic ring 5 and the reducing ring 6 are assembled on the second dust cover 33.

[0028] As Figure 4 shown, the detection assembly 4 includes a cage 41, a PCBA board 42, and a wire harness 43. The two ends of the cage 41 are respectively fixedly connected to the first bushing 21 and the second bushing 31. The PCBA board 42 is connected to the cage 41. A magnetic sensor and an acceleration sensor are connected to the PCBA board 42. The wire harness 43 is connected to the PCBA board 42. The PCBA board 42 detects the signal of the magnetic ring 5 and outputs it through the wire harness 43.

[0029] The detection component 4 is located between the first bushing component 2 and the second bushing component 3. The cage 41 is connected and assembled with the first bushing 21 and the second bushing 31 as a whole. The PCBA board 42 and the wire harness 43 are both assembled and stand on the cage 41. The detection circuit on the PCBA board 42 includes at least one pair of magnetosensitive sensors, a road cadence signal output, and an acceleration sensor. The magnetosensitive sensors are used to obtain the magnetic field change between the magnetic ring 5 and the hollow shaft 11, and the acceleration sensor is used to obtain the speed change of the rotation of the hollow shaft 11.

[0030] The PCBA board 42 and the magnetic ring 5 are components that are to have relative movement. The magnetic ring 5 rotates following the hollow shaft 11, and the PCBA board 42 is fixed; when stepping on the hollow shaft 11, the torsion force will cause a slight deformation of the hollow shaft 11 itself, and the magnetic field change caused by the deformation will be detected by the detection component. The PCBA board 42 can judge the rotation of the hollow shaft 11 by detecting the signal of the magnetic ring 5.

[0031] The PCBA board 42 is a combination of sensor detection components, and the detection components can detect the change of the subtle magnetic field intensity; the hollow shaft 11 is both a part for transmitting torque and a deformed part. The hollow shaft 11 is made of inverse magnetostrictive material, and the magnetic domains inside the material are combed into a regular arrangement through a process. When the hollow shaft 11 bears torque, the magnetic domains can form a larger magnetic field according to the designed rule; the magnetic ring 5 is used to detect the road cadence signal and identify the forward and reverse rotation of the hollow shaft 11. When pedaling during cycling, the hollow shaft 11 will deform, and the magnetic field will also change under the influence of the deformation. This change can be recognized by the detection component and corresponding feedback can be made.

[0032] The outside of the PCBA board 42 is covered with injection plastic 44. The connection end of the wire harness 43 and the PCBA board 42 are injection molded and sealed, improving the waterproof, dustproof and earthquake resistance performance of the signal processing board.

[0033] As Figure 6 shown, the detection component 4 further includes a sealing ring 45. Sealing grooves are provided at both ends of the cage 41, and the sealing ring 45 is connected in the sealing grooves. The cage 41 is connected to the inner wall of the first bushing 21 and / or the second bushing 31 through the sealing ring 45. The cage 41 is hermetically connected to the bushing, which can increase the tightness of the connection between the cage 41 and the bushing, and can also play a waterproof role to prevent the detection component 4 from getting water and affecting the operation of the PCBA.

[0034] As Figure 5 shown, the one-piece crank bottom bracket assembly 1 further includes a left crank 12 and a right crank 13. Both ends of the hollow shaft 11 are respectively connected to the left crank 12 and the right crank 13, and the left crank 12 and the right crank 13 form 180°.

[0035] The integrated crank bottom bracket assembly 1 further includes a chainring 14 and crank bolts 15. One end of the hollow shaft 11 is press-fitted with the right crank 13 and the chainring 14 as a whole, and the left crank 12 is fastened to the other end of the hollow shaft 11 through the crank bolts 15. When the integrated crank bottom bracket is installed, it passes through the first bushing assembly 2, the detection assembly 4, and the second bushing assembly 3 and then is fastened to the left crank 12. The left crank 12 and the right crank 13 are installed corresponding to each other at 180°.

[0036] In the utility model, the integrated crank bottom bracket and the press-in type torque sensor are taken as a whole. The sensor collects the deformation and rotation of the hollow shaft 11, and outputs externally through the wire harness 43 after collecting signals through the detection assembly 4. In the assembly process, first, the first bushing assembly 2 is installed at one end of the bottom bracket shell, then the detection assembly 4 and the second bushing assembly 3 are installed together at the other end of the bottom bracket shell. Then, the hollow shaft 11 of the integrated chainring 14 is inserted through the end of the second bushing assembly 3 and passes out through the first bushing assembly 2, and the left crank 12 and the crank screws are installed for fixation.

[0037] The press-in type bottom bracket shell is a standard configuration on high-end road bikes. The bottom bracket shell hollow shaft structure of the utility model reduces the number of parts, reduces the weight, and improves the structural rigidity. As a press-in type torque sensor does not require screwing in, the overall structure is simple. The design of the frame bottom bracket shell can be wider, and the design space of the frame is larger. The support points of the bottom bracket are wider, providing better support and better transmission of pedaling force.

[0038] The integrated crank bottom bracket press-in type torque sensor of the utility model integrates the sensor, the hollow shaft, the crank, etc. The overall structure is simple, reducing the number of parts, reducing the weight, and improving the structural rigidity. The design of the frame bottom bracket shell can be wider, the design space of the frame is larger, the support points of the bottom bracket assembly are wider, providing better support and better transmission of pedaling force. It can realize the rapid installation of the torque sensor, effectively reducing the assembly problems of the existing screw-in type torque sensor. When the hollow shaft rotates under the pedaling of the crank, the detection assembly collects the torque signal of the shaft deformation and the speed signal of the shaft rotation, and transmits them externally through the wire harness 43.

[0039] The above content is a further detailed description of the utility model in combination with specific preferred embodiments, and it cannot be determined that the specific implementation of the utility model is only limited to these descriptions. For those of ordinary skill in the technical field to which the utility model belongs, without departing from the concept of the utility model, several simple deductions or substitutions can still be made, and all should be regarded as belonging to the protection scope of the utility model.

Claims

1. An integrated crankshaft press-fit torque sensor structure, characterized in that: It includes an integrated crank shaft assembly, a first sleeve assembly, a second sleeve assembly, a detection assembly, and a magnetic ring. The integrated crank shaft assembly includes a hollow shaft. The first sleeve assembly, the detection assembly, and the second sleeve assembly are sequentially butt-jointed and assembled as a whole. The hollow shaft passes through the first sleeve assembly, the detection assembly, and the second sleeve assembly. The hollow shaft rotates relative to the detection assembly. The magnetic ring rotates synchronously with the hollow shaft. The detection assembly identifies changes in the magnetic field between the magnetic ring and the hollow shaft.

2. The torque sensor structure of the integrated crankshaft press-in type according to claim 1 is characterized in that: The first sleeve assembly includes a first sleeve, a first bearing, and a first dust cover. The outer ring of the first bearing is fixed to the first sleeve, and the first dust cover is fixed to the inner ring of the first bearing. The second sleeve assembly includes a second sleeve, a second bearing, and a second dust cover. The outer ring of the second bearing is fixed to the second sleeve, and the second dust cover is fixed to the inner ring of the second bearing. The first dust cover and the second dust cover are fixed on the hollow shaft, and the detection assembly is respectively connected to the first sleeve and the second sleeve.

3. The torque sensor structure of the integrated crankshaft press-in type according to claim 2 is characterized in that: It also includes a reducing ring, which is connected to one end of the first dust cover and / or the second dust cover, and the magnetic ring is connected to the reducing ring.

4. The torque sensor structure of the integrated crankshaft press-in type according to claim 2 is characterized in that: The detection component includes a holder, a PCBA board, and a wiring harness. The two ends of the holder are respectively fixedly connected to the first sleeve and the second sleeve. The PCBA board is connected to the holder. A magnetic sensor and an acceleration sensor are connected to the PCBA board. The wiring harness is connected to the PCBA board. The PCBA board detects the signal of the magnetic ring and outputs it through the wiring harness.

5. The torque sensor structure of the integrated crankshaft press-in type according to claim 4 is characterized in that: The outside of the PCBA board is covered with injection molding glue.

6. The torque sensor structure of the integrated crankshaft press-fit type according to claim 4, characterized in that: The detection assembly also includes a sealing ring. Sealing grooves are provided at both ends of the retaining frame. The sealing ring is connected in the sealing groove. The retaining frame is connected to the inner wall of the first shaft sleeve and / or the second shaft sleeve through the sealing ring.

7. The torque sensor structure of the integrated crankshaft press-in type according to claim 1 is characterized in that: The integrated crank shaft assembly also includes a left crank and a right crank. The two ends of the hollow shaft are respectively connected to the left crank and the right crank. The left crank and the right crank are 180 degrees apart.

8. The torque sensor structure of the integrated crankshaft press-in type according to claim 7, characterized in that: The integrated crank shaft assembly also includes a chainring and a crank bolt. One end of the hollow shaft is pressed together with the right crank and the chainring, and the left crank is fastened to the other end of the hollow shaft by the crank bolt.

9. The torque sensor structure of the integrated crankshaft press-in type according to claim 1, characterized in that: The hollow shaft is made of reverse magnetostrictive material.

Images