Middle shaft treading force detection mechanism based on middle shaft radial strain tension detection

Abstract

The utility model discloses a center shaft treading force detection mechanism based on center shaft radial strain tension detection, which comprises a center shaft arranged at two ends in a five-way pipe in a penetrating manner and used for mounting a crank, one end of the center shaft is also fixed with a chain wheel, and the chain wheel is connected with a chain wheel of a rear wheel through a chain; the center shaft is supported in the bowl piece through a center shaft bearing, the end, close to the center shaft fixing crankset, of the bowl piece extends out of the bottom bracket and is provided with an expanded bowl opening, an eccentric ring is embedded in the bowl piece, and an inner ring of the eccentric ring is rotationally assembled on the center shaft through an eccentric ring bearing; the center of the outer ring is eccentrically arranged relative to the axis of the middle shaft, a spring piece fixed to the eccentric ring and the bowl piece is further embedded in the bowl opening, a strain gauge is attached to the spring piece, radial tension transmitted to the middle shaft through the chain wheel by the chain is used for driving the eccentric ring to rotate relative to the center of the eccentric ring, and the eccentric ring drives the spring piece to generate micro deformation. And the strain gauge induces to output a treading force signal. According to the mechanism, the pedal force detection precision is higher, the problem of false detection of the strain gauges is solved, the structure is simpler, and assembly is easier.

Description

Technical Field

[0001] The utility model relates to a spindle pedaling force detection mechanism based on spindle radial strain tension detection. Background Art

[0002] An electric bicycle is usually equipped with a spindle pedaling force detection mechanism to detect the pedaling force signal in real time and accurately determine the riding state (light pedaling or heavy pedaling) of the rider based on the pedaling force signal, so as to drive the motor to adjust the power output. As is well known, since the most direct method for measuring the spindle pedaling force is to measure the torque or bending moment received by the spindle, the common spindle pedaling force detection mechanisms on the market at present directly attach strain gauges to the spindle to detect its torque or bending moment. However, in long-term use practice, such detection mechanisms have the following problems:

[0003] 1. There are many interference factors on the spindle, which greatly affect the detection accuracy of the pedaling force thereon;

[0004] Theoretically, when a person steps on the pedal and transmits the pedaling force to the spindle through the crank, a torque is generated on the spindle. However, in practice, due to the influence of the radial tension transmitted by the chain on the sprocket on the spindle, a part of the torque generated by the pedaling force will be offset, resulting in a reduction in the accuracy of the torque signal finally detected by the strain gauge.

[0005] 2. Since the strain gauge is directly fixed on the rotating spindle, 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 between the inner and outer coils. Due to the transmission loss existing in the wireless induction method between the inner and outer coils and the signal being easily interfered, the output intensity and accuracy of the signal are far lower than those of the direct connection signal line output method, which results in a further reduction in the accuracy and reliability of the final pedaling force detection data.

[0006] 3. When using the wireless induction method between the inner and outer coils to transmit the torque signal, both the inner and outer coils need to be installed deep inside the bottom bracket tube, and the internal space of the bottom bracket tube is occupied, making the radial size of the mechanism larger. 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. Summary of the Invention

[0007] The purpose of the utility model is to provide a spindle pedaling force detection mechanism based on spindle radial strain tension detection for the deficiencies of the existing spindle pedaling force detection mechanism mentioned in the background art. It not only has higher detection accuracy of the pedaling force, can eliminate the problem of misdetection by the strain gauge, but also has a simpler structure and is easier to assemble.

[0008] The technical solution of the present utility model is: A spindle pedal force detection mechanism based on the detection of radial strain tension of the spindle, including a spindle passing through both ends inside the bottom bracket shell for installing cranks, and a chainring is fixed at one end of the spindle. The chainring is connected to a sprocket on the rear wheel of the electric bicycle through a chain; it is characterized in that it further includes a bowl member passing through the bottom bracket shell. The spindle is supported by a spindle bearing and arranged inside the bowl member. One end of the bowl member close to the chainring fixed on the spindle extends out of the bottom bracket shell to set an enlarged bowl mouth. An eccentric ring is embedded in the bowl mouth. The inner ring of the eccentric ring is rotationally assembled on the spindle through an eccentric ring bearing. The center of the outer ring of the eccentric ring is eccentrically arranged relative to the axis of the spindle. A spring piece fixed to both the eccentric ring and the bowl member is also embedded in the bowl mouth. A strain gauge is attached to the spring piece. The radial tension transmitted from the chainring to the spindle through the chain is used to drive the eccentric ring to rotate relative to the center of the eccentric ring. The eccentric ring drives the spring piece to generate a micro-deformation, so that the strain gauge senses the micro-deformation to output a pedal force signal.

[0009] Further, in the present utility model, the eccentric ring is fixed to the spring piece by a pin shaft or a screw, or a convex column is fixedly protruded on the eccentric ring, and the convex column cooperates with a connection hole provided on the spring piece to fix the spring piece, or the eccentric ring is provided with a connection hole, which cooperates with a convex column fixedly protruded on the spring piece to fix the spring piece.

[0010] Further, in the present utility model, the spring piece is fixed to the bowl member by a plurality of locking screws, and a pressing cover for covering and axially pressing the spring piece is fixed on the bowl mouth. A signal processing PCB board electrically connected to the strain gauge is arranged inside the pressing cover, and the lead wire of the signal processing PCB board is led out through a lead wire port arranged on the pressing cover.

[0011] Further, in the present utility model, the rear wall of the enlarged bowl mouth abuts against the outer wall of one end of the bottom bracket shell. A locking nut is further included. The end of the bowl member without the bowl mouth extends out of the other end of the bottom bracket shell, and a thread is formed on its outer periphery for screwing the locking nut to abut against the outer wall of this end of the bottom bracket shell. The locking nut and the enlarged bowl mouth cooperate together to axially lock the bowl member on the bottom bracket shell.

[0012] Further, in the present utility model, the eccentric ring bearing is a stamping outer ring needle bearing.

[0013] Further, in the present utility model, an inner step is provided at the end of the bowl member without the bowl mouth, and a shaft shoulder is correspondingly formed on the spindle. The spindle bearing abuts between the inner step and the shaft shoulder, and an outer retaining ring for clamping the spindle bearing in cooperation with the inner step, and an inner retaining ring for clamping the spindle bearing in cooperation with the shaft shoulder are also embedded in the bowl member.

[0014] Further, in the present utility model, the eccentric ring bearing is integrally formed on the inner ring of the eccentric ring.

[0015] Furthermore, a lubricating bearing is installed between the outer ring of the eccentric ring and the inner circumference of the bowl opening to reduce the rotational resistance of the eccentric ring.

[0016] The working principle of the present utility model is as follows:

[0017] Same as the conventional technology, pedals are fixed on the cranks at both ends of the central shaft. The lead wires of the signal processing PCB board are finally electrically connected to the controller of the electric bicycle.

[0018] During cycling, the pedaling force exerted by a person will be transmitted to the rear wheel (sprocket) through the chainring and the chain. Under the action of the reaction force, the chain will give the central shaft a radial pulling force pointing to the rear wheel. The eccentric ring has a tendency to rotate around its own center under the action of this radial pulling force. At this time, the spring piece radially fixed to the eccentric ring will be pulled and deformed slightly under the fixing action at the fixed point, which is then sensed by the strain gauge. The strain gauge will generate a signal change and transmit it to the signal processing PCB board. The signal processing PCB board will process the signal change and output 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 torsion of the eccentric ring and the deformation of the spring piece will change accordingly, and the signal changes transmitted by the strain gauge will also be different, thus achieving the function of accurately detecting the pedaling force.

[0019] The advantages of the present utility model are as follows:

[0020] The present utility model not only has higher detection accuracy of the pedaling force, but also eliminates the problem of false detection of the strain gauge, and has a simpler structure and is easier to assemble. Its specific advantages are elaborated as follows:

[0021] 1. In the structural design of the present utility model, the pedaling force exerted by a person is transmitted to the rear wheel (sprocket) through the chainring and the chain. Under the action of the reaction force, the chain will give the central shaft a radial pulling force pointing to the rear wheel. The eccentric ring generates torque and triggers the deformation of the spring piece to make the strain gauge output a torque signal only under the action of this radial pulling force. Therefore, the detection and acquisition of the torque signal exclude many interference factors and have higher detection accuracy.

[0022] 2. In the structural design of the present utility model, neither the strain gauge nor the signal processing PCB board rotates with the central shaft. Therefore, the signal of the strain gauge can be directly connected to the signal processing PCB board 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 vulnerability to interference existing in the wireless induction method of the inner and outer coils, which improves the output strength and accuracy of the signal qualitatively, and further ensures the accuracy and reliability of the final torque detection data.

[0023] 3. In the structural design of the present utility model, since the strain gauge signal data extraction method of wireless induction between the inner and outer coils is cancelled, not only are the components including the inner and outer coils, corresponding brackets, etc. saved, but also since there is no need to install deep inside the five-way pipe, the internal volume space of the five-way pipe is not occupied. Therefore, while the radial dimension of the entire bottom bracket pedal force detection mechanism is reduced, the structure is more simple and compact, and assembly, maintenance, and disassembly are extremely convenient, effectively improving production efficiency while reducing maintenance costs.

[0024] 4. The lead wires of the signal processing PCB board in the present utility model are directly led out from the lead wire holes of the gland on the outermost side of the bowl mouth, without the need to route the signal wires through the inner side of the five-way pipe with grooves as in the prior art. The extraction of the signal wires is very smooth and convenient, facilitating subsequent wiring and maintenance.

[0025] 5. The eccentric ring, spring piece, and gland in the present utility model are all integrally fixed inside the bowl mouth at one end of the bowl part. The assembly is convenient, and they can be produced modularly together with the bowl part. It is small, light, and has a compact structure, facilitating adaptation and installation with various five-way pipes, and helping to improve the appearance neatness and aesthetics of electric bicycles. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The present utility model will be further described below in conjunction with the drawings and embodiments:

[0027] Figure 1 is the overall three-dimensional structure schematic diagram of an embodiment of the present utility model;

[0028] Figure 2 is Figure 1 the axial sectional view (removing the crank and chainring);

[0029] Figure 3 is Figure 2 the right view;

[0030] Figure 4 is Figure 3 the view after removing the gland;

[0031] Figure 5 is Figure 4 the view after removing the spring piece;

[0032] Figure 6 is Figure 1 the single three-dimensional structure schematic diagram of the eccentric ring in

[0033] Figure 7 is the axial sectional view (removing the crank and chainring) of another embodiment of the present utility model;

[0034] Figure 8 is Figure 7 the right view;

[0035] Figure 9 View after removing the gland Figure 7 ;

[0036] Figure 10 View after removing the spring piece Figure 7 ;

[0037] Figure 11 Schematic diagram of the three-dimensional structure of the eccentric ring with an eccentric ring bearing integrally provided therein Figure 7

[0038] Among them: 1. Five-way pipe; 2. Crank; 3. Bottom bracket spindle; 3a. Axle shoulder; O1. Axis center; 4. Chainring; 5. Chain; 6. Sprocket; 7. Cup; 7a. Inner step; 701. Cup mouth; 8. Bottom bracket bearing; 9. Eccentric ring; O2. Center; A. Fixed point; 10. Eccentric ring bearing; 11. Spring piece; 12. Strain gauge; 13. Pin shaft; 14. Gland; 14a. Lead wire port; 15. Signal processing PCB board; 16. Lock nut; 17. Outer retaining ring; 18. Inner retaining ring; 19. Locking screw; 20. Lubricated bearing Specific embodiments

[0039] Figures 1 - 6 Example 1: The specific embodiments of the bottom bracket pedal force detection mechanism based on the bottom bracket radial strain tension detection provided by the present invention are described as follows with reference to shown below:

[0040] This bottom bracket pedal force detection mechanism based on the bottom bracket radial strain tension detection, like the conventional technology, has a bottom bracket spindle 3 passing through both ends of the five-way pipe 1 for installing the crank 2. One end of the bottom bracket spindle 3 is also fixedly provided with a chainring 4 inside the crank 2 at this end. The chainring 4 is connected to a sprocket 6 on the rear wheel of the bicycle through a chain 5

[0041] Figure 5 The core improvement of the present invention lies in that: a cup 7 is inserted into the five-way pipe 1. The bottom bracket spindle 3 is supported by a bottom bracket bearing 8 and arranged inside the cup 7. One end of the cup 7 near the chainring 4 fixed to the bottom bracket spindle 3 extends out of the five-way pipe 1 to set an enlarged cup mouth 701. An eccentric ring 9 (the centers of its inner and outer rings do not overlap) is embedded in the cup mouth 701. The inner ring of the eccentric ring 9 is rotationally assembled on the bottom bracket spindle 3 through an eccentric ring bearing 10, so that the center of the inner ring of the eccentric ring 9 overlaps with the axis center O1 of the bottom bracket spindle 3, while the center O2 of the outer ring is eccentrically arranged (does not overlap) relative to the axis center O1 of the bottom bracket spindle 3. See specifically Figure 2 shown, and the connection line between the two points to the ground. A fixed point A is provided on the eccentric ring 9. The fixed point A is radially fixed to a spring piece 11 also embedded in the cup mouth 701 through a pin shaft 13. At the same time, the lower part of the spring piece 11 is fixed to the bottom wall of the cup mouth 701 of the cup 7 (axially nailed in) by three locking screws 19. Specifically combined with Figure 2As shown. A strain gauge 12 is attached to the spring piece 11. The radial tensile force transmitted by the chain 5 to the central shaft 3 via the chainring 4 is used to drive the eccentric ring 9 to rotate relative to the center O2 of the eccentric ring 9, and the eccentric ring 9 drives the spring piece 11 to generate a micro-deformation, so that the strain gauge 12 senses this micro-deformation to output a pedaling force signal.

[0042] And specifically in combination with Figure 2 and Figure 3 As shown, in this embodiment, a gland 14 for covering and axially pressing the spring piece 11 is also fixed on the inner circumference of the bowl mouth 701. A hook (not marked in the figure) is provided on the outer circle of the gland 14 and is matched with a card slot (not marked in the figure) provided on the inner circumference of the bowl mouth 701 to complete the fixing. A signal processing PCB board 15 electrically connected to the strain gauge 12 is provided inside the gland 14, and the lead wires of the signal processing PCB board 15 are led out through a lead wire port 14a provided on the gland 14.

[0043] Still as Figure 2 As shown, in this embodiment, the rear wall of the enlarged bowl mouth 701 abuts against the outer wall of one end of the bottom bracket shell 1. It further includes a lock nut 16. The end of the bowl part 7 where the bowl mouth 701 is not provided extends out of the other end of the bottom bracket shell 1, and a thread is formed on its outer circumference for screwing the lock nut 16 to abut against the outer wall of this end of the bottom bracket shell 1. The lock nut 16 and the enlarged bowl mouth 701 cooperate together to axially lock the bowl part 7 on the bottom bracket shell 1.

[0044] In this embodiment, the eccentric ring bearing 10 is a pressed outer ring needle bearing.

[0045] In this embodiment, the bottom bracket bearing 8 is sleeved near the end of the central shaft 3 where the chainring 4 is not fixed. An inner step 7a is provided at the end of the bowl part 7 where the bowl mouth 701 is not provided, and a shaft shoulder 3a is correspondingly formed on the central shaft 3. The bottom bracket bearing 8 abuts between the inner step 7a and the shaft shoulder 3a, and an outer retaining ring 17 for clamping the bottom bracket bearing 8 in cooperation with the inner step 7a and an inner retaining ring 18 for clamping the bottom bracket bearing 8 in cooperation with the shaft shoulder 3a are also embedded in the bowl part 7.

[0046] And, in combination with Figures 2 - 5 As shown, in this embodiment, the fixed point A, the center O2 of the eccentric ring 9, and the axis O1 of the central shaft 3 are arranged in sequence from top to bottom. At the same time, the fixed point A, the center O2 of the eccentric ring 9, and the axis O1 of the central shaft 3 are collinear and point to the ground.

[0047] And, in this embodiment, the inner ring of the eccentric ring 9 and the eccentric ring bearing 10 are designed to be disengaged. After removing the eccentric ring bearing 10, the three-dimensional structure of the single eccentric ring 9 is as Figure 6 shown.

[0048] The working principle of the present invention is as follows:

[0049] Similar to the conventional technology, pedals (omitted in the figure) are fixed on the cranks 2 at both ends of the central shaft 3. The lead wires of the signal processing PCB board 15 are finally electrically connected to the controller of the electric bicycle.

[0050] During cycling, the pedaling force exerted by a person will be transmitted to the rear wheel (sprocket 6) through the chainring 4 and the chain 5. Under the action of the reaction force, the chain 5 will give the central shaft 3 a radial tension force pointing to the rear wheel. Under the action of this radial tension force, the eccentric ring 9 has a tendency to rotate around its own center O2. At this time, under the fixing action of the pin shaft 13 at the fixed point A, the spring piece 11 radially fixed to the eccentric ring 9 will be pulled and generate a small deformation, which will be sensed by the strain gauge 12. The strain gauge 12 will generate a signal change and transmit it to the signal processing PCB board 15. The signal processing PCB board 15 will process the signal change and output 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 torque of the eccentric ring 9 and the deformation of the spring piece 11 will change accordingly, and the signal changes transmitted by the strain gauge 12 will also be different, so as to achieve the function of accurately detecting the pedaling force.

[0051] For the above structural design of the present invention, the pedaling force exerted by a person is transmitted to the rear wheel (sprocket 6) through the chainring 4 and the chain 5. Under the action of the reaction force, the chain 5 will give the central shaft 3 a radial tension force pointing to the rear wheel. The eccentric ring 9 generates torque only under the action of this radial tension force and triggers the deformation of the spring piece 11 to make the strain gauge 12 output a torque signal. Therefore, the detection and acquisition of the torque signal exclude many interference factors and have higher detection accuracy.

[0052] Moreover, since neither the strain gauge 12 nor the signal processing PCB board 15 rotates with the central shaft 3, the signal of the strain gauge 12 can be directly connected to the signal processing PCB board 15 by wires without the need to be led out by means of wireless induction of internal and external coils. Therefore, there are no problems of transmission loss and signal susceptibility to interference existing in the wireless induction method of internal and external 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.

[0053] Moreover, since the method of leading out the signal data of the strain gauge 12 by wireless induction of internal and external coils is cancelled, not only the components including internal and external coils, corresponding brackets, etc. are saved, but also since there is no need to install deeply inside the bottom bracket 1, it does not occupy the volume space inside the bottom bracket 1. Therefore, while the radial dimension of the entire central shaft pedaling force detection mechanism is reduced, the structure is simpler and more compact, and the assembly, maintenance and disassembly are extremely convenient, effectively improving the production efficiency while reducing the maintenance cost.

[0054] Moreover, since the lead wires of the signal processing PCB board 15 are directly led out from the lead wire holes 14a of the gland 14 on the outermost side of the bowl opening 701, there is no need to route the wires through the inner groove of the five-way pipe 1 as in the prior art. The leading out of the signal wires is very smooth and convenient, facilitating subsequent wiring and maintenance.

[0055] In addition, since the eccentric ring 9, the spring piece 11 and the gland 14 are all integrally fixed inside the bowl opening 701 at one end of the bowl member 7, the assembly is convenient. They can be modularly produced together with the bowl member 7, being small, light, and having a compact structure. This facilitates the adaptation and installation with various five-way pipes 1 and helps to improve the cleanliness and aesthetic appearance of the electric bicycle.

[0056] Embodiment 2: Referring to Figures 7 - 11 Another embodiment of the bottom bracket pedal force detection mechanism based on the radial strain tension detection of the bottom bracket of the present utility model is shown. Its overall structure is basically the same as that of Embodiment 1. It also has a bottom bracket 3 passing through the five-way pipe 1 with cranks 2 installed at both ends. One end of the bottom bracket 3 is also fixed with a chainring 4 inside the crank 2 at this end. The chainring 4 is connected to a sprocket 6 on the rear wheel of the bicycle through a chain 5. A bowl member 7 is inserted into the five-way pipe 1. The bottom bracket 3 is supported by a bottom bracket bearing 8 and arranged inside the bowl member 7. The bowl member 7 has an enlarged bowl opening 701 extending out of the five-way pipe 1 at one end close to the chainring 4 fixed to the bottom bracket 3. An eccentric ring 9 is embedded in the bowl opening 701. The inner ring of the eccentric ring 9 is also rotationally assembled on the bottom bracket 3 through an eccentric ring bearing 10, so that the center of the inner ring of the eccentric ring 9 coincides with the axis O1 of the bottom bracket 3, while the center O2 of the outer ring is eccentrically arranged relative to the axis O1 of the bottom bracket 3 (not coinciding). Specifically, see Figure 5 shown, and the line connecting the two points points to the ground.

[0057] Furthermore, referring to Figure 7 and Figure 11 shown, the difference in structure between this embodiment and Embodiment 1 is that the inner ring of the eccentric ring 9 is integrally formed with the eccentric ring bearing 10, and the eccentric ring bearing 10 is also a stamped outer ring needle bearing. At the same time, a lubricating bearing 20 is embedded between the outer ring of the eccentric ring 9 and the inner circumference of the bowl opening 701 to reduce the rotational resistance of the eccentric ring.

[0058] In addition, similar to Embodiment 1, a fixed point A is also provided on the eccentric ring 9 in this embodiment. The fixed point A is radially fixed to a spring piece 11 also embedded in the bowl opening 701 through a pin 13. At the same time, the lower part of the spring piece 11 is fixed to the bottom wall of the bowl opening 701 of the bowl member 7 (axially nailed in) by three locking screws 19. Specifically, referring to Figure 7 shown. A strain gauge 12 is attached to the spring piece 11. The radial tension transmitted from the chain 5 through the chainring 4 to the bottom bracket 3 is used to drive the eccentric ring 9 to rotate relative to the center O2 of the eccentric ring 9. The eccentric ring 9 drives the spring piece 11 to generate a micro-deformation, so that the strain gauge 12 senses this micro-deformation to output a pedal force signal.

[0059] And specifically in combination with Figure 7 and Figure 8 As shown, within the inner circumference of the bowl mouth 701 in this embodiment, there is also fixedly installed a gland 14 for covering and axially pressing the spring piece 11. Different from Embodiment 1, the gland 14 is sleeved on the bowl mouth 701, and hooks (not marked in the figure) are provided on the inner circumference of the gland 14, which cooperate with the card slots (not marked in the figure) provided on the outer circumference of the bowl mouth 701 to complete the fixation. A signal processing PCB board 15 electrically connected to the strain gauge 12 is provided inside the gland 14, and the lead-out wire of the signal processing PCB board 15 is led out through the lead-out wire port 14a provided on the gland 14.

[0060] Still as Figure 7 As shown, for the enlarged bowl mouth 701 in this embodiment, the rear wall thereof abuts against the outer wall of one end of the five-way pipe 1. It further includes a lock nut 16. One end of the bowl member 7 where the bowl mouth 701 is not provided extends out of the other end of the five-way pipe 1, and a thread is formed on its outer circumference for screwing the lock nut 16 to abut against the outer wall of this end of the five-way pipe 1. The lock nut 16 and the enlarged bowl mouth 701 cooperate together to axially lock the bowl member 7 on the five-way pipe 1.

[0061] In this embodiment, the middle shaft bearing 8 is sleeved near one end of the middle shaft 3 that does not fixedly mount the chainring 4. One end of the bowl member 7 where the bowl mouth 701 is not provided is provided with an inner step 7a, and a shaft shoulder 3a is correspondingly formed on the middle shaft 3. The middle shaft bearing 8 abuts between the inner step 7a and the shaft shoulder 3a, and an outer retaining ring 17 that cooperates with the inner step 7a to clamp the middle shaft bearing 8, and an inner retaining ring 18 that cooperates with the shaft shoulder 3a to clamp the middle shaft bearing 8 are also embedded inside the bowl member 7.

[0062] And, in combination with Figures 7 - 10 As shown, in this embodiment, the fixed point A, the center O2 of the eccentric ring 9, and the axis O1 of the middle shaft 3 are arranged in sequence from top to bottom. At the same time, the three points of the fixed point A, the center O2 of the eccentric ring 9, and the axis O1 of the middle shaft 3 are on a straight line and point to the ground.

[0063] Compared with Embodiment 1, in this embodiment, the eccentric ring 9 and the inner eccentric ring bearing 10 are integrally designed, which is not only structurally compact but also very convenient for assembly and disassembly. In addition, the introduction of the lubricating bearing 20 on the outer ring of the eccentric ring 9 also improves the working reliability and sensitivity of the eccentric ring 9. For the basic working principle and its implementation effect of this embodiment, reference can be made to the description of Embodiment 1, and details will not be repeated here.

[0064] Certainly, the above embodiments are only for explaining the technical concept and features of the present utility model. 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 and essence 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 bottom bracket pedaling force detection mechanism based on bottom bracket radial strain tension detection, comprising a bottom bracket (3) disposed at both ends inside a bottom bracket shell (1) for installing cranks (2), a chainring (4) is further fixed to one end of the bottom bracket (3), and the chainring (4) is connected to a sprocket (6) on the rear wheel of a bicycle through a chain (5); characterized in that It further includes a bowl member (7) disposed within a five-way pipe (1). The central shaft (3) is supported within the bowl member (7) by a central shaft bearing (8). One end of the bowl member (7) near the central shaft (3) where the chainring (4) is fixed extends out of the five-way pipe (1) to form a bowl opening (701) with an enlarged diameter. An eccentric ring (9) is embedded within the bowl opening (701). The inner ring of the eccentric ring (9) is rotatably assembled on the central shaft (3) via an eccentric ring bearing (10). The center (O2) of the outer ring of the eccentric ring (9) is eccentrically disposed relative to the axis (O1) of the central shaft (3). A spring plate (11) that is fixed to both the eccentric ring (9) and the bowl member (7) is also embedded within the bowl opening (701). A strain gauge (12) is attached to the spring plate (11). The radial tension transmitted from the chainring (5) to the central shaft (3) is used to drive the eccentric ring (9) to rotate relative to the center (O2) of the eccentric ring (9), causing the spring plate (11) to undergo a micro-deformation. The strain gauge (12) senses this micro-deformation to output a pedaling force signal.

2. The central axis pedaling force detection mechanism based on central axis radial strain tension detection according to claim 1, characterized in that The eccentric ring (9) is fixed to the spring plate (11) by a pin shaft (13) or a screw, or a convex post is protrudingly fixed on the eccentric ring (9), and the convex post cooperates with a connection hole provided on the spring plate (11) to fix the spring plate (11), or the eccentric ring (9) is provided with a connection hole, which cooperates with a convex post protrudingly fixed on the spring plate (11) to fix the spring plate (11).

3. The pedal force detection mechanism for the central axis based on the detection of the central axis radial strain and tensile force according to claim 1, characterized in that The spring plate (11) is fixed to the bowl member (7) by a plurality of locking screws (19). A gland (14) for covering and axially pressing the spring plate (11) is fixed on the bowl opening (701). A signal processing PCB board (15) electrically connected to the strain gauge (12) is provided within the gland (14). The lead wires of the signal processing PCB board (15) are led out through a lead wire opening (14a) provided on the gland (14).

4. The central axis pedaling force detection mechanism based on central axis radial strain and tension detection according to claim 1, wherein For the bowl opening (701) with an enlarged diameter, its rear wall abuts against the outer wall of one end of the five-way pipe (1). A locking nut (16) is further included. One end of the bowl member (7) where the bowl opening (701) is not provided extends out of the other end of the five-way pipe (1), and a thread is formed on its outer periphery for screwing the locking nut (16) to abut against the outer wall of this end of the five-way pipe (1). The locking nut (16) and the bowl opening (701) with an enlarged diameter cooperate to axially lock the bowl member (7) on the five-way pipe (1).

5. The central axis pedal force detection mechanism based on central axis radial strain tension detection according to claim 1, characterized in that The eccentric ring bearing (10) is a pressed outer ring needle bearing.

6. The central axis pedaling force detection mechanism based on central axis radial strain tension detection according to claim 1, characterized in that One end of the bowl member (7) where the bowl opening (701) is not provided is provided with an inner step (7a), and a shaft shoulder (3a) is correspondingly formed on the central shaft (3). The central shaft bearing (8) is disposed between the inner step (7a) and the shaft shoulder (3a). An outer retaining ring (17) that cooperates with the inner step (7a) to clamp the central shaft bearing (8), and an inner retaining ring (18) that cooperates with the shaft shoulder (3a) to clamp the central shaft bearing (8) are also embedded within the bowl member (7).

7. The central axis pedaling force detection mechanism based on central axis radial strain tension detection according to claim 1, wherein The eccentric ring bearing (10) is integrally formed on the inner ring of the eccentric ring (9).

8. The pedal force detection mechanism based on central axis radial strain and tension detection according to claim 1 or 7, characterized in that A lubricating bearing (20) is fitted between the outer ring of the eccentric ring (9) and the inner circumference of the bowl mouth (701).

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