Clutch assembly and electric bicycle

Abstract

The invention relates to a clutch assembly and an electric bicycle. The clutch assembly includes: a clutch; the torque sensor assembly comprises a strain sleeve arranged on the outer side of a clutch in a sleeving mode and used for being in transmission connection with the clutch, the outer wall of the strain sleeve is provided with a strain area and a torque output area in the axial direction, and the thickness of the strain area is smaller than that of the torque output area; and the strain sensing element is fixed on the outer wall of the strain area. The strain sleeve sleeves the outer side of the clutch, so that the torque sensor assembly which originally needs to occupy large axial space of the middle shaft and the clutch are integrated, the axial space of the middle shaft can be saved, efficient utilization of the axial space of the middle shaft is achieved, and the torque sensor assembly and the clutch are preassembled. The operation difficulty is reduced; and the steps of a terminal customer assembly process are simplified. The thickness of the strain area is smaller than that of the torque transmission area, deformation of the strain area is facilitated, and the signal acquisition sensitivity of the torque sensor assembly is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electric bicycle electric power assist, and particularly to a clutch assembly and an electric bicycle. BACKGROUND

[0002] The electric bicycle (also known as electric bicycle) has a power assist system, which includes a motor and can realize the integration of human-powered riding and motor assist. At present, more and more electric bicycles adopt a torque sensor installed on the middle shaft, so that during riding, the pedaling force of the feet during human riding can be converted into a corresponding voltage signal output, and the frequency signal output of the middle shaft at different rotating speeds can be realized through the Hall sensor, and then the power output of the motor can be controlled after signal processing by the motor control circuit board, so that the pedaling force of the feet during human riding can be greatly saved.

[0003] In the related art, the detection method of the middle shaft torque is to measure the stress or strain generated by the middle shaft under the action of the torque, that is, the change of the stress or strain causes the change of the magnetic field, so that the excitation coil, the detection coil, the signal processing unit and the Hall sensor element realize the signal output of the middle shaft at different rotating speeds and different torque states, so as to control the power output of the motor through the motor controller, and the torque sensor can adjust the motor output power according to the measured torque of the middle shaft to improve the riding comfort.

[0004] Limited by the narrow axial space of the sensor and detection system installed inside the middle shaft of the electric bicycle, the traditional clutch assembly and torque sensor system often occupy a large axial space of the middle shaft, which puts higher requirements on the design of small-sized and high-integrated clutch or torque detection system. SUMMARY

[0005] To overcome the problems in the related art, the present application provides a clutch assembly and an electric bicycle.

[0006] According to a first aspect of the embodiments of the present application, the present application provides a clutch assembly, comprising: a clutch; a torque sensor assembly, comprising: a strain sleeve, sleeved outside the clutch, for driving connection with the clutch, an outer wall of the strain sleeve being provided with a strain area and a torque output area along the axial direction, the thickness of the strain area being smaller than the thickness of the torque output area; and a strain sensing element, the strain sensing element being fixed to the outer wall of the strain area.

[0007] In some embodiments, the clutch assembly further comprises a support bearing, the support bearing being arranged axially with the clutch, and the strain sleeve being sleeved outside the support bearing and axially covering the support bearing.

[0008] In some embodiments, the clutch is arranged axially on one side of the strain region, and the clutch is axially staggered with the torque output region.

[0009] In some embodiments, the strain region has an axial dimension smaller than that of the clutch, and the strain region has an axial dimension smaller than that of the torque output region.

[0010] In some embodiments, the strain sleeve is axially provided with a first baffle abutting against one end of the clutch away from the support shaft, for axially defining the retainer of the clutch, and a second baffle abutting against one end of the support bearing away from the clutch, for axially defining the retainer of the support bearing.

[0011] In some embodiments, the torque sensor assembly further comprises a signal transmission assembly, which is sleeved outside the strain region, and an outer wall of the signal transmission assembly is flush with an outer wall of the torque output region.

[0012] In some embodiments, the outer wall of the signal transmission assembly is provided with a radially protruding anti-rotation device.

[0013] In some embodiments, the strain sensing element is a strain gauge or a magnetostrictive material.

[0014] In some embodiments, the clutch is a one-way clutch.

[0015] According to a second aspect of the embodiments of the present disclosure, the present disclosure provides an electric bicycle, comprising: a middle shaft; a clutch assembly as described in the first aspect, which is sleeved outside the outer wall of the middle shaft, and the middle shaft transmits torque to the strain sleeve through the clutch.

[0016] The technical solutions provided by the embodiments of the present disclosure can have the following beneficial effects: the strain sleeve is sleeved outside the clutch, the torque sensor assembly and the clutch, which originally need to occupy a large axial space of the middle shaft, are integrated, not only saving the axial space of the middle shaft, realizing efficient use of the axial space of the middle shaft, but also greatly simplifying the steps of the end customer assembly process, reducing the operation difficulty and assembly cost. In addition, the thickness of the strain region is smaller than that of the torque transmission region, which is more conducive to the deformation of the strain region and improves the signal acquisition sensitivity of the torque sensor assembly. BRIEF DESCRIPTION OF DRAWINGS

[0017] The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments consistent with the present disclosure and serve to explain the principles of the present disclosure together with the specification.

[0018] Figure 1 is a perspective sectional view of a clutch assembly according to an exemplary embodiment;

[0019] Figure 2 is a perspective structural schematic view of a clutch assembly according to an exemplary embodiment; DETAILED DESCRIPTION

[0020] The exemplary embodiments will be described in detail with reference to the drawings. In the following description, the same numbers are used to denote the same elements, unless otherwise indicated. The embodiments described in the following exemplary embodiments are not meant to represent all embodiments consistent with the present disclosure. Rather, they are merely examples of apparatus and methods consistent with some aspects of the present disclosure as detailed in the appended claims.

[0021] According to embodiments of the present disclosure, the clutch assembly is suitable for installation in an electric bicycle. For better understanding of the present disclosure, unless otherwise specified, axial, radial and circumferential refer to the axial, radial and circumferential of the clutch assembly; the axial one side refers to the left side in Figure 1 , Figure 2 the right side refers to the right side in Figure 1 , Figure 2 ; the radial outer side refers to the side away from the center axis O in Figure 1 (the upper side in Figure 1 ), the radial inner side refers to the side close to the center axis O in Figure 1 (the lower side in ). In addition, "driving connection" refers to the ability to transmit driving force / torque between two components, which can be directly connected or through various transmission mechanisms or connecting structures to achieve the above functions. The term "anti-torque connection" refers to the connection between two elements in a manner that does not rotate relative to each other, which can be achieved via a press fit (i.e., an interference fit) or by integrally forming the two components referred to. The specific meaning of the above terms in the present disclosure can be understood by those of ordinary skill in the art in light of the specific circumstances.

[0022] To solve the above technical problems, the present disclosure provides a clutch assembly 100 applied to the middle shaft (not shown in the figure) of an electric bicycle, for transmitting the torque of the middle shaft to the sprocket, realizing power transmission, and also detecting the pedaling force applied by the rider on the middle shaft. Therefore, the clutch assembly 100 can realize the functions of torque transmission and stress and strain detection in the limited axial space of the middle shaft.

[0023] Figure 1 Specifically, as Figure 2As shown, the clutch assembly 100 at least comprises the clutch 10, the support bearing 20 and the torque sensor assembly 30.

[0024] Wherein, the clutch 10 and the support bearing 20 are both sleeved on the outer wall of the intermediate shaft, and the support bearing 20 and the clutch 10 are adjacent to each other along the axial direction of the intermediate shaft, so that the retainer of the support bearing 20 and the retainer of the clutch 10 can be limited in the axial direction, ensuring the relative stability of the two in the axial position. However, the retainer of the support bearing 20 and the retainer of the clutch 10 are clearance fit in the axial direction, so that there is a moderate space between them in the axial direction, thereby effectively avoiding excessive wear and jamming of the retainer of the clutch 10 and the retainer of the support bearing 20 when they operate with each other, improving the overall operation efficiency and service life of the clutch assembly 100. In addition, the support bearing 20 can stably play the role of radial support, thereby consolidating the stability and durability of the clutch assembly 100.

[0025] Wherein, the clutch 10 can be selected as a one-way clutch 10 or a two-way clutch 10 according to actual needs. In this embodiment, the clutch assembly 100 is applied in an electric bicycle, so the clutch 10 is selected as a one-way clutch 10. When the rider pedals the pedals forward, the one-way clutch 10 can effectively transmit the pedal force and the power of the motor to the sprocket through the intermediate shaft, thereby driving the wheels to move forward. Conversely, when the rider pedals the pedals backward, the one-way clutch 10 will automatically disconnect the connection between the intermediate shaft and the sprocket, preventing the pedal force from acting on the motor in the reverse direction, thereby avoiding unnecessary energy loss and negative impact on the motor. Therefore, the one-way clutch 10 not only guarantees smooth power transmission during riding, but also ensures the normal operation of the motor, thereby improving the overall riding performance and energy efficiency of the electric bicycle.

[0026] Further, the torque sensor assembly 30 is sleeved outside the clutch 10 and the support bearing 20, and the torque sensor assembly 30 comprises a strain sleeve 31, a strain sensing element 32 and a signal transmission assembly 33.

[0027] Specifically, the strain sleeve 31 is in a cylindrical structure and is sleeved on the radial outside of the clutch 10 and the support bearing 20. The strain sleeve 31 can be drivingly connected with the clutch 10, i.e. the inner wall of the strain sleeve 31 can form a torque input area with the clutch 10, and the length of the torque input area of the inner wall of the strain sleeve 31 in the axial direction is usually equal to the axial length of the clutch 10, so as to receive the torque transmitted by the clutch 10 when it rotates in a certain direction. The outer wall of the strain sleeve 31 is provided with a strain area 311 and a torque output area 312 in the axial direction, and the torque output area 312 is torsionally connected with the driving sleeve of the sprocket, so that the strain sleeve 31 outputs torque to the sprocket through the torque output area 312.

[0028] When the torque is effectively transmitted from the clutch 10 to the driving sleeve (not shown in the figure) of the sprocket through the strain sleeve 31 under the action of the one-way clutch 10, the strain region 311 of the strain sleeve 31 will be deformed slightly. The strain sensing element 32 is fixed on the outer wall of the strain region 311, which can capture the deformation and convert it into an electrical signal. Then, these electrical signals are transmitted through the signal transmission assembly 33, and the controller inside the signal transmission assembly 33 can analyze and interpret these signals in real time, and generate corresponding control instructions according to the deformation amount. Finally, the controller will adjust the output power of the motor in real time according to the instructions, so as to realize precise control of the electric bicycle power-assisted system, ensure that the power output during riding matches the pedaling force applied by the rider on the axle, and improve the riding comfort and energy utilization efficiency.

[0029] Further, the outer wall of the strain sleeve 31 is divided into a strain region 311 and a torque output region 312 along the axial direction, and the thickness of the strain region 311 is less than that of the torque output region 312. The strain region 311 is designed to be thinner, which is to make it easier to deform when the strain sleeve 31 is subjected to torque, so that the strain sensing element 32 located on the strain region 311 can more easily capture the slight deformation signal caused by torque transmission, and the signal collected by the strain sensing element 32 is more sensitive and accurate, and can more accurately reflect the pedaling force applied on the axle.

[0030] On the other hand, the torque output region 312 is designed to be thicker, and since the torque output region 312 is connected to the driving sleeve of the chain ring in a torsion-resistant manner to ensure reliable torque transmission, the thicker torque output region 312 has higher strength and wear resistance, which not only effectively prevents structural damage under high torque output, but also greatly improves the fatigue resistance and wear resistance of the strain sleeve 31, thereby prolonging the service life of the entire clutch assembly 100.

[0031] Therefore, the outer wall structure design of the strain sleeve 31 of the present disclosure not only has a simple structure, but also takes into account the sensitivity of torque detection and the stability of torque transmission.

[0032] Further, in the present embodiment, as shown in Figure 1 and Figure 2As shown, the clutch 10 and support bearing 20 inside the strain sleeve 31 are arranged in the same order as the strain region 311 and the torque output region 312. That is, the clutch 10 is arranged axially on one side of the strain sleeve 31 corresponding to the strain region 311, while the support bearing 20 is arranged axially on the other side of the strain sleeve 31 corresponding to the torque output region 312. The clutch 10 and the torque output region 312 are at least offset in the axial direction, that is, the torque input region and the torque output region 312 on the strain sleeve 31 are at least non-overlapping in the axial direction.

[0033] Thus, a certain axial distance exists between the torque input area (the area where torque is applied by the clutch 10) and the torque output area 312 (the area transmitted to the sprocket) on the strain sleeve 31, preventing most of the torque on the strain sleeve 31 from being directly output to the sprocket radially. This structural design creates a shear force environment on the strain sleeve 31, which is more conducive to causing deformation in the strain area 311 during torque transmission, thereby enabling the strain sensing element 32 to detect torque changes in the strain area 311 more sensitively and accurately.

[0034] In this embodiment, by adding a support bearing 20 and allowing the strain sleeve 31 to axially cover the support bearing 20, under the same axial space constraints, the strain sleeve 31 of this disclosure can effectively increase the axial length of the torque output region 312, so that the torque output region 312 has higher structural strength and wear resistance. When facing high torque output operations, the longer torque output region 312 can effectively resist structural damage that may be caused by stress concentration, significantly improving the ability of the strain sleeve 31 to withstand high intensity and long-term operation, thereby significantly extending the service life of the entire clutch assembly 100.

[0035] Meanwhile, the axial dimension of the strain region 311 on the strain sleeve 31 can be smaller than the axial length of the torque output region 312. This design fully considers the actual needs of strain detection. It is only necessary to ensure that the strain region 311 has sufficient length to capture and respond to the strain effect caused by torque changes, without adding unnecessary axial space. This allows for more axial space for the torque output region 312, ensuring the strength of the strain sleeve 31 and achieving the dual goals of compact structure and high functional efficiency.

[0036] Furthermore, the axial dimension of the strain region 311 is smaller than that of the torque output region 312. This increases the length of the torque input region applied by the clutch 10 to the strain sleeve 31, thereby dispersing the stress distribution, effectively preventing excessive stress concentration, and avoiding the strain sleeve 31 from being twisted off when receiving a large torque input.

[0037] Furthermore, the torque input region and the torque output region 312 partially overlap axially. This provides a buffering and balancing effect during high-torque operation, preventing the strain sleeve 31 from breaking due to excessive local stress caused by a sudden surge in torque. The structure of the strain sleeve 31 disclosed herein ensures both effective torque transmission and sufficient durability and safety under high-intensity working conditions, thereby extending the service life and reliability of the clutch assembly 100.

[0038] It can be further understood that in this embodiment Figure 1 The specific layout of the strain region 311 and torque output region 312 shown, and their length relationship with the clutch 10, are merely exemplary and not intended to limit the scope of protection of this disclosure. In other possible embodiments, the total length of the strain sleeve 31, the axial extension lengths of the strain region 311 and torque output region 312, and their respective thicknesses can be flexibly adjusted according to different requirements for actual torque detection sensitivity. For example, in some cases, the total length of the strain sleeve 31 can be greater than the sum of the axial lengths of the clutch 10 and the support bearing 20. Similarly, the axial length of the strain region 311 of the strain sleeve 31 can also be greater than the axial length of the clutch 10 to ensure that the strain sensing element 32 can more accurately and comprehensively capture the deformation signal under torque. In short, the specific values ​​of these parameters are not fixed and can be freely adjusted and configured according to actual needs and design.

[0039] In this embodiment, as Figure 1 As shown, the strain sleeve 31 is provided with a first baffle 313 and a second baffle 314 along the axial direction. The first baffle 313 abuts against the cage of the clutch 10 at the end away from the support bearing 20, and is used to axially limit the cage of the clutch 10, ensuring the range of movement of the clutch 10 in the axial direction, and preventing the stability of torque transmission and the accuracy of strain detection from being affected by excessive axial movement.

[0040] The second baffle 314 abuts against the cage at the end of the support bearing 20 away from the clutch 10, and is used to axially limit the cage of the support bearing 20, thus ensuring the range of axial movement of the support bearing 20. The first baffle 313 and the second baffle 314 work together to prevent axial movement of the clutch 10 and the support bearing 20 during operation, thereby ensuring the operational stability of the entire clutch assembly 100, extending the service life of the clutch assembly 100, and ensuring the effective transmission of torque and the reliability of strain measurement.

[0041] It should be noted that the terms "first," "second," etc., are used to describe various structures, but these structures should not be limited to these terms. These terms are only used to distinguish structures of the same type from each other and do not indicate a specific order or degree of importance. In fact, the expressions "first," "second," etc., can be used interchangeably. For example, without departing from the scope of this disclosure, the first baffle 313 can also be referred to as the second baffle 314, and similarly, the second baffle 314 can also be referred to as the first baffle 313.

[0042] Furthermore, in this embodiment, the signal transmission component 33 is sleeved outside the strain region 311. The signal transmission component 33 can typically power the strain sensing unit, receive the strain signal generated by the strain region 311, and transmit these signals to the controller (not shown in the figure) via the cable 331.

[0043] To further ensure the stability of the signal transmission component 33 during the operation of the clutch assembly 100, especially in high-speed rotating environments, the signal transmission component 33 is typically designed to be circumferentially fixed to prevent it from rotating with the clutch assembly 100. In some embodiments, the outer wall of the signal transmission component 33 is provided with a radially protruding anti-rotation device 332. The anti-rotation device 332 is typically an axially extending long protrusion structure. By preventing unnecessary rotational movement of the signal transmission component 33 through mechanical locking or other means, the signal transmission process remains stable during the operation of the clutch assembly 100, preventing signal transmission interruption or distortion due to rotation, and effectively improving the reliability and accuracy of the entire torque detection system.

[0044] Meanwhile, the signal transmission component 33 and the strain sleeve 31 in the torque sensor component 30, especially the strain region 311, are radially spaced apart. This ensures that even when the clutch assembly 100 rotates at high speed, the signal transmission component 33 is unaffected by rotation, guaranteeing the accuracy and reliability of signal transmission and effectively achieving real-time monitoring and precise control of torque changes. Furthermore, the signal transmission component 33 can also detect the rotational speed of the clutch assembly 100.

[0045] Furthermore, the outer wall of the signal transmission component 33 can be flush with the outer wall of the torque output region 312. This minimizes the occupation of radial space, making the entire structure more compact and facilitating the integration of more components or functional modules within a limited space.

[0046] Furthermore, the flush outer walls of the signal transmission component 33 and the strain sleeve 31 simplify the installation and mating with the drive sleeve of the sprocket, facilitating the assembly and maintenance of the overall structure. At the same time, the uniform appearance design makes the entire clutch assembly 100 more visually harmonious and aesthetically pleasing.

[0047] In this embodiment, the strain sensing element 32 used to detect strain is of various types, including but not limited to strain gauges, magnetostrictive materials, etc. The strain gauge can be fixed to the outer wall of the strain region 311 by adhesive, ensuring that when the strain region 311 of the strain sleeve 31 is subjected to torque and deforms, the strain gauge can accurately capture this deformation and convert it into a measurable electrical signal.

[0048] Magnetostrictive materials can be deposited or attached to the outer wall of the strain region 311 through electroplating, spraying, or sputtering processes to form a sensing layer that responds to torque changes. The selected magnetostrictive material possesses excellent inverse magnetostrictive effect and high magnetic permeability. When subjected to an external magnetic field or mechanical stress, the material undergoes dimensional changes, thereby achieving precise sensing and conversion of torque changes. This characteristic enables magnetostrictive materials to exhibit high precision and high stability in torque sensors, effectively improving the performance of the torque detection system.

[0049] Based on the same inventive concept, this disclosure provides an electric bicycle, including: a bottom bracket, a clutch assembly 100, and a sprocket (not shown). The clutch assembly 100 is sleeved on the outer wall of the bottom bracket and is connected to the bottom bracket for transmission. The bottom bracket can transmit torque to the strain sleeve 31 through the clutch 100. The drive sleeve of the sprocket is torsionally sleeved on the outer wall of the strain sleeve 31.

[0050] The specific manner in which the functions of the electric bicycle in the above embodiments are implemented has been described in detail in the embodiments relating to the clutch assembly 100, and will not be elaborated here.

[0051] In summary, the strain sleeve 31 is fitted onto the outside of the clutch 10, integrating the torque sensor assembly 30, which would otherwise require a significant amount of axial space on the central shaft, with the clutch 10. This not only saves axial space on the central shaft, achieving efficient utilization of that space, but also greatly simplifies the assembly process for end customers, reducing operational difficulty and assembly costs. Furthermore, the thickness of the strain region 311 is less than that of the torque transmission region, which is more conducive to deformation of the strain region 311, improving the signal acquisition sensitivity of the torque sensor assembly 30.

[0052] Other embodiments of this disclosure will readily occur to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. This application is intended to cover any variations, uses, or adaptations of this disclosure that follow the general principles of this disclosure and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered exemplary only, and the true scope and spirit of this disclosure are indicated by the following scope of claims.

[0053] It should be understood that this disclosure is not limited to the precise structures described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of this disclosure is limited only by the appended claims.

Claims

1. A clutch assembly (100), characterized in that, include: Clutch (10); Torque sensor assembly (30), comprising: A strain sleeve (31) is sleeved on the outside of the clutch (10) for transmission connection with the clutch (10). The outer wall of the strain sleeve (31) is provided with a strain region (311) and a torque output region (312) along the axial direction. The thickness of the strain region (311) is smaller than the thickness of the torque output region (312). A strain sensing element (32) is fixed to the outer wall of the strain region (311).

2. The clutch assembly (100) according to claim 1, characterized in that, The clutch assembly (100) further includes a support bearing (20) axially arranged with the clutch (10), and the strain sleeve (31) is sleeved on the outside of the support bearing (20) and axially covers the support bearing (20).

3. The clutch assembly (100) according to claim 1, characterized in that, The clutch (10) is axially disposed on one side corresponding to the strain region (311), and the clutch (10) and the torque output region (312) are at least axially offset.

4. The clutch assembly (100) according to claim 1, characterized in that, The axial dimension of the strain region (311) is smaller than that of the clutch (10), and the axial dimension of the strain region (311) is smaller than that of the torque output region (312).

5. The clutch assembly (100) according to claim 2, characterized in that, The strain sleeve (31) is provided axially with: A first baffle (313) abuts against one end of the clutch (10) away from the support shaft, and is used to axially define the retainer of the clutch (10); The second baffle (314) abuts against the end of the support bearing (20) away from the clutch (10) and serves to axially define the cage of the support bearing (20).

6. The clutch assembly (100) according to claim 1, characterized in that, The torque sensor assembly (30) further includes a signal transmission assembly (33), which is sleeved outside the strain region (311), and the outer wall of the signal transmission assembly (33) is flush with the outer wall of the torque output region (312).

7. The clutch assembly (100) according to claim 6, characterized in that, The outer wall of the signal transmission component (33) is provided with a radially protruding anti-rotation device (332).

8. The clutch assembly (100) according to claim 1, characterized in that, The strain sensing element (32) is a strain gauge or a magnetostrictive material.

9. The clutch assembly (100) according to claim 1, characterized in that, The clutch (10) is a one-way clutch (10).

10. An electric bicycle, characterized in that, include: Central axis; as well as The clutch assembly (100) as described in any one of claims 1 to 9 is sleeved on the outer wall of the central shaft, the central shaft transmitting torque to the strain sleeve (31) through the clutch (10).

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