Card base torque detection mechanism based on flywheel radial stress detection

Abstract

The utility model discloses a card base torque detection mechanism based on flywheel radial stress detection, which comprises a card base arranged on a motor shaft on the outer side of an end cover of a hub motor and a torque sensing assembly arranged on the card base, and is characterized in that the card base comprises a motor shaft sleeve fixedly arranged on the motor shaft and a card base outer ring arranged on the periphery of the motor shaft sleeve through a card base inner bearing; a flywheel is fixed on the outer ring of the card base; the torque sensing device is characterized in that the torque sensing assembly is arranged on the side, opposite to the hub motor, of the flywheel, the torque sensing assembly comprises a deformation component fixed to a motor shaft sleeve and attached with a strain gauge, the deformation component is provided with an annular stress part, and the flywheel is provided with an annular force application part; the clamping base outer bearing is in radial contact with the annular stress part so as to transmit radial force. The card base torque detection mechanism provided by the utility model is higher in torque signal acquisition precision, simple in structure and easy to assemble.

Description

Technical Field

[0001] The utility model relates to a torque detection mechanism for a card base based on the detection of the radial force of a flywheel. Background Art

[0002] For the consideration of component integration design of existing electric bicycles, a torque sensing component for detecting the pedaling force of a person is usually installed on the card base outside the hub motor to form a torque detection mechanism for the card base. Currently, the common torque detection mechanisms for card bases on the market mainly set the strain element in the torque sensing component on the outer ring of the relatively rotating card base. A flywheel is fixed on the outer ring of the card base at the same time. When a person rides a bicycle, the pedaling force drives the middle shaft crank and the chainring to drive the chain to move, and then pulls the flywheel to rotate to transmit torque, so that the outer ring of the card base is stressed and undergoes micro-deformation. The strain element senses the micro-deformation of the outer ring of the card base and is converted by the signal processing circuit in the torque sensing component to obtain a torque detection signal.

[0003] However, through practical applications, we found that the above-mentioned torque detection mechanism for the card base exposes the following problems:

[0004] 1. The composition of the force detected and obtained from the outer ring of the card base is relatively complex, which includes both the radial tension applied by the chain to the flywheel and then acting on the outer ring of the card base, the torsion generated by the flywheel driving the outer ring of the card base to rotate, and may also include the feedback force acting on the outer ring of the card base through the ratchet one-way clutch by the hub shell, etc. This makes it very difficult to accurately and effectively identify the force truly transmitted by the pedaling force from it, resulting in the detection accuracy of the torque sensing component being affected.

[0005] Currently, the common countermeasures in the industry are usually to use a signal processing circuit with complex calculations to identify and distinguish the force, but such signal processing circuits have a high cost and the actual effect is not ideal.

[0006] 2. Since the strain element in the torque sensing component for detecting torque is fixed on the rotating outer ring of the card base, the output of its signal cannot be directly led out by a direct connection signal line, but can only be led out by means of wireless induction of internal and external coils. Due to the transmission loss existing in the wireless induction method of internal and external coils itself, and the signal is vulnerable to interference, the output intensity and accuracy of the signal are far less than those of the output method of direct connection of the signal line, which leads to a reduction in the accuracy and reliability of the final torque detection data.

[0007] 3. When using the wireless induction method of internal and external coils to transmit the torque signal, both the internal and external coils need to be installed deep inside the outer ring of the card base. And in order to avoid the outer card base bearing, the installation position is inward (at the connection end of the card base and the hub motor). In addition, a corresponding bracket is required to fix the PCB board of the coil, with a complex structure, many components, and very cumbersome and inconvenient assembly, maintenance and disassembly, resulting in low production efficiency and high cost maintenance problems. Summary of the Invention

[0008] The object of the present utility model is to provide a card base torque detection mechanism based on the radial force detection of a flywheel, aiming at the deficiencies of the existing card base torque detection mechanism mentioned in the background technology. It not only has higher accuracy in collecting torque signals, but also has a simple structure and is easy to assemble.

[0009] The technical solution of the present utility model is: A card base torque detection mechanism based on the radial force detection of a flywheel, including a card base installed on the motor shaft outside the end cover of a hub motor and a torque sensing component arranged on the card base. The card base includes a motor shaft sleeve fixed on the motor shaft and a card base outer ring arranged around the motor shaft sleeve through a bearing inside the card base. A flywheel is fixed on the card base outer ring. It is characterized in that: The torque sensing component is arranged on the side of the flywheel facing away from the hub motor. The torque sensing component includes a deformation member fixed to the motor shaft sleeve and attached with strain gauges. The deformation member has an annular force-receiving part, and the flywheel is provided with an annular force-applying part, which is in radial contact with the annular force-receiving part through a bearing outside the card base to transmit radial force.

[0010] Further preferably, in the present utility model, the deformation member includes a deformation ring fixed to the motor shaft sleeve and attached with the strain gauges. An annular force-receiving rib is formed on the deformation ring protruding towards the hub motor along the axial direction of the motor shaft as the annular force-receiving part, and an annular force-applying rib located inside or outside the annular force-receiving rib is formed on the flywheel protruding towards the deformation ring along the axial direction of the motor shaft as the annular force-applying part. The annular force-applying rib is in radial contact with the annular force-receiving rib through the bearing outside the card base to transmit radial force.

[0011] Further preferably, in the present utility model, the deformation member is integrally formed with the motor shaft sleeve.

[0012] Further preferably, in the present utility model, the flywheel is integrally formed with the card base outer ring.

[0013] Even more preferably, in the present utility model, there are two or more strain gauges, which are attached to the ring surface of the deformation ring and are evenly spaced at equal angles along the center of the deformation ring.

[0014] Further preferably, in the present utility model, the torque sensing component further includes a protective shell fixed to the motor shaft sleeve and a signal processing PCB board arranged inside the protective shell and electrically connected to the strain gauges. The lead-out wire of the signal processing PCB board is led out through an opening on the protective shell.

[0015] More preferably, in the present utility model, the protective case includes an annular cover shell, the rear part of the annular cover shell closely adheres to the deformation member, and the front part of the annular cover shell is an opening part, on which a detachable cover plate is fixed, and the opening hole is arranged on the cover plate for leading out the lead wire.

[0016] Further preferably, in the present utility model, the outer ring of the card base is connected to the end cover of the hub motor through a ratchet pawl one-way clutch. A ratchet is fixed on the outer ring of the card base, and it is connected and cooperated with the pawl arranged on the end cover of the hub motor to form the ratchet pawl one-way clutch; or a pawl is fixed on the outer ring of the card base, and it is connected and cooperated with the ratchet arranged on the end cover of the hub motor to form the ratchet pawl one-way clutch.

[0017] More preferably, in the present utility model, a step frequency measurement magnetic ring is fixed on the inner peripheral wall of the outer ring of the card base, and a Hall element which is arranged opposite to the step frequency measurement magnetic ring is arranged on the motor shaft sleeve, and the Hall element is electrically connected to the signal processing PCB board.

[0018] More preferably, in the present utility model, the inner bearing of the card base and the outer bearing of the card base are distributed in a staggered manner in the axial direction of the card base, and the setting position of the step frequency measurement magnetic ring in the axial direction of the card base is located between the inner bearing of the card base and the outer bearing of the card base.

[0019] The working principle of the present utility model is as follows:

[0020] Same as the conventional technology, the flywheel is connected to the chainring arranged on the middle shaft of the electric bicycle through a chain, and pedals are fixed at both ends of the middle shaft through cranks. The lead wire of the signal processing PCB board is finally electrically connected to the controller of the electric bicycle.

[0021] During riding, the pedaling force applied by a person to the pedals is transmitted to the flywheel through the chainring and the chain. The flywheel then applies a radial pulling force to the deformation member through the outer bearing of the card base, causing the deformation member (the deformation ring therein) to undergo a micro-deformation. The strain gauge senses the micro-deformation and generates an induction signal, which is processed by the signal processing PCB board and then outputs a torque signal to control the speed of the motor output of the electric bicycle. According to the different pedaling forces of a person, the deformation amount of the deformation member sensed by the strain gauge will also change, and the magnitude of the output torque signal will also change, so as to achieve the function of accurately detecting the pedaling force.

[0022] The advantages of the present utility model are:

[0023] The present utility model not only has higher accuracy in collecting torque signals, but also has a simple structure and is easy to assemble. Its specific advantages are as follows:

[0024] 1. In the structural design of the present utility model, the deformed structure in the torque sensing assembly and the flywheel are connected through a card base outer bearing to complete the transmission of radial force. This enables, after the pedaling force is transmitted to the flywheel via the chainring and the chain, a precise radial tension to be directly applied to the deformed member, forcing it to deform and be sensed by the strain gauge, thereby excluding the interference factors of other external forces, enhancing the recognition accuracy of the pedaling force, and greatly improving the accuracy of the final detection data of the torque detection mechanism. Moreover, it also saves the production cost of the signal processing circuit that applies complex calculations in the prior art.

[0025] 2. In the structural design of the present utility model, the entire torque sensing assembly is fixed on the non-rotating motor shaft sleeve in the card base. The signal of the strain gauge therein can be directly connected to the signal processing PCB board by wires, without the need to lead it out by means of the wireless induction of the inner and outer coils. Therefore, there are no problems of transmission loss and signal susceptibility to interference existing in the wireless induction method of the inner and outer coils, which qualitatively improves the output intensity and accuracy of the signal, and further ensures the accuracy and reliability of the final torque detection data.

[0026] 3. In the structural design of the present utility model, its torque sensing assembly is directly arranged on the outside of the outer ring of the card base and on the side of the flywheel facing away from the hub motor, and the disassembly and assembly are very convenient. Since the method of leading out the signal data of the strain gauge by wireless induction of the inner and outer coils is cancelled, not only are the components including the inner and outer coils and the corresponding brackets saved, but also, because there is no need to install deeply inside the outer ring of the card base, it does not occupy the volume space inside the outer ring of the card base. Therefore, the radial dimension of the entire card base torque detection mechanism is reduced, the structure is more simple and compact, and the assembly, maintenance and disassembly are extremely convenient, effectively improving the production efficiency while reducing the maintenance cost.

[0027] 4. The card base, the flywheel and the torque sensing assembly in the present utility model are integrated into a standard component, which is convenient for modular production, and the overall installation and disassembly from the motor shaft can simplify the production and manufacturing processes of the enterprise and save the production cost.

[0028] 5. The lead wire of the torque sensing assembly in the present utility model is directly led out from the opening of the protective shell fixed on the outer ring of the card base, without the need to route the signal wire through the inner side groove of the outer ring of the card base as in the prior art. The leading out of the signal wire is very smooth and convenient, which is convenient for subsequent wiring and maintenance. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The present utility model will be further described below in conjunction with the drawings and embodiments:

[0030] Figure 1 is the main axial sectional view of the present utility model;

[0031] Figure 2This is the radial front view of the state where the present utility model is connected to the center shaft chainring through a chain drive (removing the protective shell outside the deformed structure);

[0032] Figure 3 This is the single radial front view of the present utility model.

[0033] Wherein: 1. Hub motor; 101. End cover; 2. Motor shaft; 3. Motor shaft sleeve; 4. Inner bearing of the base; 5. Outer ring of the base; 6. Flywheel; 601. Annular force-applying rib; 7. Strain gauge; 8. Deformable member; 801. Deformable ring; 802. Annular force-receiving rib; 9. Outer bearing of the base; 10. Protective shell; 10a. Annular cover; 10b. Cover plate; 11. Signal processing PCB board; 12. Lead wire; 13. Ratchet and pawl one-way clutch; 14. Magnetic ring for measuring pedal frequency; 15. Hall element; 16. Frame; 17. Chain; 18. Center shaft; 19. Chainring; 20. Crank; 21. Pedal. Detailed implementation manners

[0034] Embodiment: The following combines Figures 1 to 3 as shown to illustrate the detailed implementation manners of the base torque detection mechanism based on the radial force detection of the flywheel provided by the present utility model as follows:

[0035] First, like the known technology, it has a hub motor 1, a base mounted on the outer side of the end cover 101 of the hub motor 1 on the motor shaft 2, and a torque sensing assembly provided on the base. Both ends of the motor shaft 2 are fixed to the frame 16. The base has a motor shaft sleeve 3 fixed on the motor shaft 2 and a base outer ring 5 disposed around the motor shaft sleeve 3 via an inner bearing 4 of the base. One end of the base outer ring 5 is connected to the end cover 101 of the hub motor 1 via a ratchet and pawl one-way clutch 13. In this embodiment, a ratchet is fixed on the base outer ring 5, and it is connected and cooperated with the pawl provided on the end cover 101 of the hub motor 1 to form the ratchet and pawl one-way clutch 13. At the same time, a flywheel 6 is fixed on the base outer ring 5.

[0036] The core improvement of the present utility model lies in that: the torque sensing assembly is arranged on the side of the flywheel 6 facing away from the hub motor 1. The torque sensing assembly includes a deformable member 8 fixed to the motor shaft sleeve 3 and attached with a strain gauge 7. The deformable member 8 has an annular force-receiving portion, and the flywheel 6 is provided with an annular force-applying portion, which is in radial contact with the annular force-receiving portion via an outer bearing 9 of the base to transmit the radial force. At the same time, the torque sensing assembly also includes a protective shell 10 fixed to the motor shaft sleeve 3 and a signal processing PCB board 11 disposed in the protective shell 10 and electrically connected to the strain gauge 7. The lead wire 12 of the signal processing PCB board 11 is led out through the opening on the protective shell 10.

[0037] Further combining Figures 1 to 3As shown in the figure, in this embodiment, the deformation member 8 is composed of a deformation ring 801 and an annular stress bar 802 formed thereon. The deformation ring is fixed on the motor shaft sleeve 3 and adheres to the strain gauge 7. An annular stress bar 802 is formed on the deformation ring 801 to protrude towards the hub motor 1 along the axial direction of the motor shaft 2 as the annular stress part. On the flywheel 6, an annular force - applying bar 601 located inside the annular stress bar 802 is formed to protrude towards the deformation ring 801 along the axial direction of the motor shaft 2 as the annular force - applying part. The annular force - applying bar 601 is in radial contact with the annular stress bar 802 through the outer bearing 9 of the card base to transmit the radial force.

[0038] In this embodiment, the deformation member 8 is integrally formed with the motor shaft sleeve 3, while the flywheel 6 is integrally formed with the outer ring 5 of the card base.

[0039] In this embodiment, there are two strain gauges 7, which are attached to the ring surface of the deformation ring 801, and they are evenly distributed at equal angles along the center of the deformation ring 801, as specifically shown in Figure 2 the figure, and these strain gauges 7 are all directly connected to the signal - processing PCB board 11 by wires.

[0040] In this embodiment, the protective shell 10 is composed of an annular cover shell 10a and a cover plate 10b. The rear part of the annular cover shell 10a closely adheres to the deformation ring 801, and the front part of the annular cover shell 10a is an opening part, on which a detachable cover plate 10b is fixed. The cover plate 10b is provided with the opening for the lead - out wire 12 to be led out, as specifically shown in Figure 3 the figure.

[0041] Again, as shown in Figure 1 the figure, in this embodiment, a magnetic ring 14 for measuring pedal frequency is fixed on the inner circumferential wall of the outer ring 5 of the card base, and a Hall element 15 is provided on the motor shaft sleeve 3 to cooperate with the magnetic ring 14 for measuring pedal frequency relatively. The Hall element 15 is electrically connected to the signal - processing PCB board 11. The inner bearing 4 of the card base and the outer bearing 9 of the card base are stagger - distributed in the axial direction of the card base, and the magnetic ring 14 for measuring pedal frequency is located between the inner bearing 4 of the card base and the outer bearing 9 of the card base in the axial direction of the card base.

[0042] Combined with Figures 1 to 3 the figure, the working principle of the above - mentioned embodiment is as follows:

[0043] Similar to the conventional technology, the flywheel 6 is connected to a chainring 19 provided on the bottom bracket 18 of the electric bicycle through a chain 17, and pedals 21 are fixed at both ends of the bottom bracket 18 through cranks 20. The lead - out wire 12 of the signal - processing PCB board 11 is finally electrically connected to the controller of the electric bicycle.

[0044] During cycling, the pedaling force applied by a person to the pedal 21 is transmitted to the freewheel 6 through the chainring 19 and the chain 17. The freewheel 6 then applies a radial tensile force to the deformation member 8 through the outer bearing 9 of the cartridge, causing the deformation member 8 (the deformation ring 801 therein) to undergo micro-deformation. The strain gauge 7 senses the micro-deformation and generates an induced signal, which is processed by the signal processing PCB board 11 and then outputs a torque signal to control the speed of the motor output of the electric bicycle. According to the different pedaling forces of a person, the amount of deformation of the deformation member 8 sensed by the strain gauge 7 will also change, and the magnitude of the output torque signal will also change, thus achieving the function of accurately detecting the pedaling force.

[0045] The utility model not only has higher accuracy in collecting torque signals, but also has a simple structure and is easy to assemble. Its specific advantages are as follows:

[0046] 1. In the structural design of the utility model, the radial force transmission connection between the deformation member 8 in the torque sensing assembly and the freewheel 6 is completed through the outer bearing 9 of the cartridge. This enables the pedaling force to be directly applied to the deformation member 8 with a precise radial tensile force to force it to deform and be sensed by the strain gauge 7 after being transmitted to the freewheel 6 through the chainring 19 and the chain 17, thereby eliminating the interference factors of other external forces, enhancing the recognition accuracy of the pedaling force, and greatly improving the accuracy of the final detection data of the torque detection mechanism. And it also saves the production cost of the signal processing circuit that applies complex calculations in the prior art.

[0047] 2. In the structural design of the utility model, the entire torque sensing assembly is fixed on the non-rotating motor shaft sleeve 3 in the cartridge. The signal of the strain gauge 7 therein can be directly connected to the signal processing PCB board 11 by wires, without the need to lead out through the wireless induction method of the inner and outer coils. Therefore, there are no problems of transmission loss and signal susceptibility to interference existing in the wireless induction method of the inner and outer coils, which improves the output intensity and accuracy of the signal qualitatively, and further ensures the accuracy and reliability of the final torque detection data.

[0048] 3. In the structural design of the utility model, its torque sensing assembly is directly arranged on the outside of the outer ring 5 of the cartridge and on the side of the freewheel 6 facing away from the hub motor 1, and the disassembly and assembly are very convenient. Since the method of leading out the strain gauge signal data by wireless induction of the inner and outer coils is cancelled, not only the components including the inner and outer coils and the corresponding brackets are saved, but also since there is no need to install deeply inside the outer ring 5 of the cartridge, it does not occupy the volume space inside the outer ring 5 of the cartridge. Therefore, the radial dimension of the entire cartridge torque detection mechanism is reduced, the structure is more simple and compact, and the assembly, maintenance and disassembly are extremely convenient, effectively improving the production efficiency while reducing the maintenance cost.

[0049] 4. In the present utility model, the card base, the flywheel 6, and the torque sensing assembly are integrated into a standard component, which is convenient for modular production. The whole can be assembled and disassembled from the motor shaft 2, which can simplify the production and manufacturing processes of enterprises and save production costs.

[0050] 5. The lead wire 12 of the torque sensing assembly in the present utility model is directly led out from the opening of the protective shell 10 fixed on the outer ring 5 of the card base, without the need to route the signal wire through the inner groove of the outer ring 5 of the card base as in the prior art. The lead-out of the signal wire is very smooth and convenient, which is convenient for subsequent wiring and maintenance.

[0051] Of course, the above embodiments are only used to illustrate the technical concept and features of the present utility model, and the purpose is to enable those who are familiar with this technology to understand the content of the present utility model and implement it accordingly, and it should not be used to limit the protection scope of the present utility model. All modifications made according to the spirit of the main technical solution of the present utility model should be covered within the protection scope of the present utility model.

Claims

1. A clamping base torque detection mechanism based on flywheel radial force detection, comprising a clamping base mounted on a motor shaft (2) outside an end cover (101) of a hub motor (1) and a torque sensor assembly arranged on the clamping base, the clamping base comprising a motor shaft sleeve (3) fixedly mounted on the motor shaft (2) and a clamping base outer ring (5) arranged on the periphery of the motor shaft sleeve (3) via a clamping base inner bearing (4), a flywheel (6) being fixed on the clamping base outer ring (5); characterized in that: The torque sensing assembly is arranged on a side of the flywheel (6) facing away from the wheel hub motor (1), and comprises a deformable member (8) fixed to the motor shaft sleeve (3) and attached with a strain gauge (7), wherein the deformable member (8) has an annular force-bearing portion, and an annular force-applying portion is provided on the flywheel (6), and the annular force-bearing portion is in radial contact with the annular force-bearing portion via a card base outer bearing (9) to transmit radial force.

2. The card base torque detection mechanism based on flywheel radial force detection according to claim 1 is characterized in that: The deformable member (8) comprises a deformable ring (801) fixed on the motor shaft sleeve (3) and attached to the strain gauge (7); an annular force rib (802) is protruded on the deformable ring (801) along the axial direction of the motor shaft (2) in the direction of the hub motor (1) as the annular force-bearing portion; and an annular force-applying rib (601) is protruded on the flywheel (6) along the axial direction of the motor shaft (2) in the direction of the deformable ring (801) and is located on the inner side or the outer side of the annular force-applying rib (802) as the annular force-applying portion; the annular force-applying rib (601) is in radial contact with the annular force-applying rib (802) via the card base outer bearing (9) to transmit radial force.

3. The card base torque detection mechanism based on flywheel radial force detection according to claim 1 or 2, characterized in that: The deformable component (8) and the motor shaft sleeve (3) are integrally formed.

4. The card base torque detection mechanism based on flywheel radial force detection according to claim 1 or 2, characterized in that: The flywheel (6) and the card base outer ring (5) are integrally formed.

5. The card base torque detection mechanism based on flywheel radial force detection according to claim 2 is characterized in that: There are more than two strain gauges (7), which are attached to the annular surface of the deformation ring (801), and are evenly spaced at equal angles along the center of the deformation ring (801).

6. The card base torque detection mechanism based on flywheel radial force detection according to claim 1, 2 or 5, characterized in that: The torque sensor assembly further comprises a protective shell (10) fixed to the motor shaft sleeve (3) and a signal processing PCB board (11) disposed in the protective shell (10) and electrically connected to the strain gauge (7), wherein the lead wire (12) of the signal processing PCB board (11) is led out through an opening in the protective shell (10).

7. The card base torque detection mechanism based on flywheel radial force detection according to claim 6 is characterized in that: The protective shell (10) comprises an annular cover shell (10a), the rear portion of the annular cover shell (10a) is in close contact with the deformable member (8), and the front portion of the annular cover shell (10a) is an opening portion, on which a detachable cover plate (10b) is fixed, and the cover plate (10b) is provided with the opening for leading out the lead wire (12).

8. The card base torque detection mechanism based on flywheel radial force detection according to claim 1 is characterized in that: The card base outer ring (5) is connected to the end cover (101) of the hub motor (1) via a ratchet pawl one-way clutch (13); a ratchet is fixed on the card base outer ring (5), and is connected and matched with a ratchet provided on the end cover (101) of the hub motor (1) to form the ratchet pawl one-way clutch (13); or a ratchet is fixed on the card base outer ring (5), and is connected and matched with a ratchet provided on the end cover (101) of the hub motor (1) to form the ratchet pawl one-way clutch (13).

9. The card base torque detection mechanism based on flywheel radial force detection according to claim 6 is characterized in that: A cadence measuring magnetic ring (14) is fixed on the inner peripheral wall of the card base outer ring (5), and a Hall element (15) corresponding to the cadence measuring magnetic ring (14) is provided on the motor shaft sleeve (3), and the Hall element (15) is electrically connected to the signal processing PCB board (11).

10. The card base torque detection mechanism based on flywheel radial force detection according to claim 9, characterized in that: The card base inner bearing (4) and the card base outer bearing (9) are staggered in the card base axial direction, and the arrangement position of the cadence measuring magnetic ring (14) in the card base axial direction is located between the card base inner bearing (4) and the card base outer bearing (9).

Images