Transmission device, driving unit and power-assisted bicycle

Abstract

The invention belongs to the technical field of power-assisted bicycles, and discloses a transmission device, a driving unit and a power-assisted bicycle. The transmission device comprises an outer ring transmission piece, an inner ring transmission piece, a transmission assembly and a motion conversion mechanism, and a retainer of the transmission assembly is located between the outer ring transmission piece and the inner ring transmission piece; the retainer is provided with a plurality of containing cavities which are arranged at intervals in the circumferential direction of the retainer and used for installing middle transmission pieces. The motion conversion mechanism comprises an action piece, a first conversion structure and a second conversion structure, one of the first conversion structure and the second conversion structure is connected with the outer ring transmission piece or the inner ring transmission piece, and the other one is connected with the action piece; the rotation of the outer ring transmission piece or the inner ring transmission piece around the first axis can be converted into the movement of the action piece in the direction of the first axis; when the action piece abuts against the retainer, the retainer has the movement tendency that the middle transmission piece is separated from the outer ring transmission piece and the inner ring transmission piece, friction abrasion can be reduced, and the service life of a product is prolonged.

Description

Technical Field

[0001] This application relates to the field of electric bicycle technology, specifically to a transmission device, a drive unit, and an electric bicycle. Background Technology

[0002] E-bikes typically have a manual mode and an assist mode. In manual mode, the drive unit is off, and the rider's power is transmitted to the crankshaft via the pedal crank, then to the chainring spline sleeve, and finally to the rear wheel via the chain. In assist mode, the drive unit is on, and the rider's power is still transmitted to the crankshaft via the pedal crank. The motor of the drive unit then outputs corresponding power according to the rider's pedaling force. This power is transmitted to the chainring spline sleeve via the transmission device, and finally to the rear wheel via the chain.

[0003] In related technologies, a one-way clutch is used in the transmission device. A one-way clutch, also called an overrunning clutch, is a device that allows the driving or driven component to transmit torque only in one direction of rotation. Patent CN118891454A discloses a drive device, a drive unit, and an electric bicycle for a drive unit. In the drive device, a friction unit forms frictional contact between the clamping element holder and the friction body. The friction unit is configured to generate frictional force between the clamping element holder and the friction body, which is separated from the clamping element holder. The frictional force is configured to delay the rotation of the clamping element holder relative to the shaft about the rotation axis, thereby enabling the free wheel device to be in a torque transmission state and an idle state through friction.

[0004] However, in patent CN118891454A, the tangential frictional contact between the friction unit and the friction body exists in all working modes. Prolonged frictional contact can lead to problems such as wear contamination, thermal decay, and wear attenuation. Summary of the Invention

[0005] The purpose of this application is to solve or at least alleviate some or all of the aforementioned problems. Therefore, the purpose of this application is to provide a transmission device, drive unit, and power-assisted bicycle that reduces contact force attenuation due to friction and wear, as well as abrasive contamination, thereby extending product lifespan and improving product reliability.

[0006] To achieve the above objectives, this application adopts the following technical solution:

[0007] In a first aspect, this application provides a transmission device, comprising:

[0008] Outer ring transmission components;

[0009] The inner ring transmission component is coaxially arranged with the outer ring transmission component around the first axis.

[0010] A transmission assembly includes an intermediate transmission member and a retainer, the retainer being located between the outer ring transmission member and the inner ring transmission member, the retainer having a plurality of receiving cavities arranged circumferentially therebetween, each of the receiving cavities being provided with the intermediate transmission member;

[0011] The motion conversion mechanism includes an actuating element, a first conversion structure, and a second conversion structure. One of the first conversion structure and the second conversion structure is connected to the outer ring drive element or the inner ring drive element, and the other is connected to the actuating element. The mechanism is capable of converting the rotation of the outer ring drive element or the inner ring drive element about a first axis into the movement of the actuating element along the direction of the first axis.

[0012] When the actuator moves to abut against the cage, the cage has a tendency to separate the intermediate transmission member from the outer ring transmission member and the inner ring transmission member.

[0013] As an alternative to the transmission device, the first conversion structure has an internal thread centered on a first axis, and the second conversion structure has an external thread that engages with the internal thread.

[0014] The internal thread is provided on the outer ring transmission member, and the external thread is provided on the actuating member; or, the external thread is provided on the inner ring transmission member, and the internal thread is provided on the actuating member.

[0015] As an optional embodiment of the transmission device, the actuator has a first position spaced apart from the cage and a second position abutting against the cage. When the actuator is in the first position, the minimum distance between the actuator and the cage is D1, and the stroke of the actuator is greater than D1 and less than 1.1D1.

[0016] As an optional solution for the transmission device, the first conversion structure is a first bushing with the internal thread, the first bushing being disposed on the actuating member, or the first bushing being sleeved on the outer ring transmission member;

[0017] And / or, the second conversion structure is a second bushing with external threads, the second bushing being disposed on the inner ring transmission member, or, the second bushing being disposed on the actuating member.

[0018] As an optional embodiment of the transmission device, when the internal thread is provided on the outer ring transmission member, the outer ring transmission member includes a first outer ring portion and a second outer ring portion disposed axially with the first outer ring portion. The first outer ring portion can cooperate with the intermediate transmission member, and the inner sidewall of the second outer ring portion is used to provide the internal thread.

[0019] As an alternative to the transmission device, the first conversion structure has a spiral groove centered on a first axis, and the second conversion structure has a slider that moves along the first axis;

[0020] The spiral groove is provided on the outer ring transmission component, and the slider is connected to the actuating component; or, the spiral groove is provided on the inner ring transmission component, and the slider is connected to the actuating component.

[0021] As an alternative to the transmission device, the first conversion structure has a gear centered on a first axis, and the second conversion structure has a rack extending along the first axis;

[0022] The gear is connected to the outer ring transmission member via a bevel gear set, the bevel gear set being used to make the rotation axis of the gear perpendicular to the first axis, and the rack being connected to the actuating member; or, the gear is connected to the inner ring transmission member via a bevel gear set, the bevel gear set being used to make the rotation axis of the gear perpendicular to the first axis, and the rack being connected to the actuating member.

[0023] As an optional embodiment of the transmission device, one of the outer ring transmission member and the inner ring transmission member is provided with a wedge-shaped groove, and a plurality of the wedge-shaped grooves are arranged at intervals along the circumference of the cage and correspond one-to-one with the intermediate transmission member. The wedge-shaped groove has a wedge-tightening end and a disengaging end.

[0024] When the intermediate transmission component is located at the wedge end of the wedge groove, the outer ring transmission component, the intermediate transmission component, and the inner ring transmission component are all in a wedge-tight state.

[0025] When the intermediate transmission component is located at the disengaged end of the wedge-shaped groove, the outer ring transmission component, the intermediate transmission component, and the inner ring transmission component are in a disengaged state.

[0026] As an alternative to the transmission device, the outer ring transmission component is configured as the power input end, and the inner ring transmission component is configured as the power output end.

[0027] Secondly, this application provides a drive unit including the transmission device as described in any of the preceding claims.

[0028] Thirdly, this application provides a power-assisted bicycle, including the drive unit as described above.

[0029] The beneficial effects of this application are as follows:

[0030] The transmission device provided in this application, by setting a motion conversion mechanism and utilizing a first conversion structure and a second conversion structure, can convert the rotation of the outer ring transmission member or the inner ring transmission member around the first axis into the movement of the actuating member along the first axis, so that the actuating member has a contact friction state abutting against the cage and a non-contact state separated from the cage, so that when the transmission device rotates abnormally at the power output end, it can ensure power separation and reduce transmission knocking.

[0031] Compared to existing technologies where frictional contact exists in all operating modes, in this application, friction between the cage and the actuator only exists when the inner ring drive rotates in the opposite direction. In the commonly used normal drive mode, there is no contact between the cage and the actuator, which reduces the contact force attenuation and abrasive contamination caused by frictional wear. Furthermore, the reverse operation of the inner ring drive is rarely used in most applications. Therefore, frictional contact can be effectively reduced, greatly extending the product's service life and improving its reliability.

[0032] The drive unit and power-assisted bicycle provided in this application, by applying the above-mentioned transmission device, can improve the reliability and stability of unidirectional transmission, reduce or avoid reverse transmission of power at the power output end, effectively reduce or avoid noise and abnormal sounds caused by the shaking of the chainring spline sleeve, and improve the rider's riding experience. Attached Figure Description

[0033] Figure 1 This is a cross-sectional view of the intermediate transmission component of the first type of transmission device provided in the embodiments of this application.

[0034] Figure 2 This is a cross-sectional view of the intermediate transmission component of the second type of transmission device provided in the embodiments of this application.

[0035] Figure 3 This is a longitudinal sectional view of the third type of transmission device provided in the embodiments of this application.

[0036] Figure 4 This is a longitudinal sectional view of the fourth type of transmission device provided in the embodiments of this application.

[0037] Figure 5 This is a longitudinal sectional view of the second conversion structure provided in this application embodiment, which is a second bushing with external threads.

[0038] Figure 6 This is a schematic diagram of the structure of the drive unit (without a housing) provided in the embodiment of this application.

[0039] Figure 7 This is a schematic diagram of the structure of the electric bicycle provided in the embodiments of this application.

[0040] In the picture:

[0041] 100. Frame; 200. Front wheel; 300. Rear wheel; 400. Pedals; 500. Crank; 600. Crankshaft; 700. Chainring spline sleeve; 800. Drive bar; 900. Drive unit; 901. Power assist motor; 902. Transmission device; 903. Drive gear; 904. Housing;

[0042] 10. Outer ring transmission component; 101. First outer ring portion; 102. Second outer ring portion;

[0043] 20. Inner ring transmission components;

[0044] 30. Wedge groove; 301. Wedging end; 302. Disengagement end;

[0045] 40. Transmission assembly; 401. Cage; 402. Intermediate transmission component;

[0046] 50. Motion conversion mechanism; 501. Actuating component; 5011. First mating part; 5012. Second mating part; 5013. Actuating part; 502. First conversion structure; 503. Second conversion structure. Detailed Implementation

[0047] The embodiments of this application are described in detail below. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar components or components having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this application, and should not be construed as limiting this application.

[0048] In the description of this application, unless otherwise expressly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection or a detachable connection; a mechanical connection or an electrical connection; a direct connection or an indirect connection through an intermediate medium; or the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0049] In the description of this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature being directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0050] The technical solution of this application will be further described below with reference to the accompanying drawings and specific embodiments.

[0051] like Figures 1 to 2 As shown, this application provides a transmission device 902, including an outer ring transmission member 10, an inner ring transmission member 20, and a transmission assembly 40. The outer ring transmission member 10 and the inner ring transmission member 20 are coaxially arranged with a first axis as the center. The transmission assembly 40 includes an intermediate transmission member 402 and a retainer 401. The retainer 401 is located between the outer ring transmission member 10 and the inner ring transmission member 20. The retainer 401 has a plurality of receiving cavities arranged at intervals along its circumference, and each receiving cavity is provided with an intermediate transmission member 402. One of the outer ring transmission member 10 and the inner ring transmission member 20 is provided with a wedge-shaped groove 30. The plurality of wedge-shaped grooves 30 are arranged at intervals along the circumference of the retainer 401 and correspond one-to-one with the intermediate transmission member 402. The wedge-shaped groove 30 has a wedge-tightening end 301 and a disengaging end 302. When the intermediate transmission component 402 is located at the wedge end 301 of the wedge groove 30, the outer ring transmission component 10, the intermediate transmission component 402, and the inner ring transmission component 20 are in a wedge-tight state; when the intermediate transmission component 402 is located at the disengagement end 302 of the wedge groove 30, the outer ring transmission component 10, the intermediate transmission component 402, and the inner ring transmission component 20 are in a disengagement state.

[0052] In some embodiments, the outer ring drive member 10 is configured as a power input end, and the inner ring drive member 20 is configured as a power output end. In other embodiments, the inner ring drive member 20 is configured as a power input end, and the outer ring drive member 10 is configured as a power output end.

[0053] exist Figure 1 In the example shown, the outer ring drive member 10 is provided with a wedge-shaped groove 30, which has a wedge-tightening end 301 and a disengaging end 302. Along the counter-clockwise direction of the outer ring drive member 10, i.e., from the wedge-tightening end 301 to the disengaging end 302 of the wedge-shaped groove 30, the distance between the inner wall of the wedge-shaped groove 30 and the intermediate drive member 402 gradually increases. When it is not necessary to transmit power from the inner ring drive member 20 to the outer ring drive member 10, the intermediate drive member 402 is located at the disengaging end 302 of the wedge-shaped groove 30, and the intermediate drive member 402, the outer ring drive member 10, and the inner ring drive member 20 are in a disengaged state. When it is necessary to transmit power from the outer ring drive member 10 to the inner ring drive member 20, the intermediate drive member 402 is located at the wedge-tightening end 301 of the wedge-shaped groove 30, and the intermediate drive member 402, the outer ring drive member 10, and the inner ring drive member 20 are in a wedge-tightening state to facilitate power transmission.

[0054] by Figure 1 Taking the example shown, the outer ring transmission component 10 is set as the power input end, and the inner ring transmission component 20 is set as the power output end. The four working modes of the transmission device 902 are:

[0055] 1) The first working mode is the normal drive mode of the power source. When the power source directly or indirectly drives the outer ring transmission component 10 to rotate counterclockwise, the intermediate transmission component 402 can move to the wedge end 301 of the wedge groove 30. Under the action of the wedge groove 30, the intermediate transmission component 402 wedges tightly with the outer ring transmission component 10 and the inner ring transmission component 20, so that the outer ring transmission component 10 transmits power to the inner ring transmission component 20 through the intermediate transmission component 402 to realize power transmission.

[0056] 2) The second working mode is the power source failure separation mode. When the outer ring transmission component 10 rotates clockwise in the opposite direction under unexpected circumstances, the intermediate transmission component 402 can move to the disengagement end 302 of the wedge groove 30. The intermediate transmission component 402 separates from the outer ring transmission component 10 and the inner ring transmission component 20, and the outer ring transmission component 10 rotates idly.

[0057] 3) The third working mode is abnormal forward rotation of the power output end. When the inner ring transmission component 20 rotates counterclockwise under unexpected circumstances, the intermediate transmission component 402 can move to the disengagement end 302 of the wedge groove 30. The intermediate transmission component 402 separates from the outer ring transmission component 10 and the inner ring transmission component 20, and the outer ring transmission component 10 rotates idly.

[0058] 4) The fourth working mode is the abnormal reversal of the power output end. When the inner ring transmission component 20 rotates clockwise in an unexpected situation, the intermediate transmission component 402 has a tendency to move to the wedge end 301 of the wedge groove 30 under the action of the inner ring transmission component 20. In order to prevent the intermediate transmission component 402 from moving to the wedge end 301 of the wedge groove 30, the transmission device 902 provided in this application also includes a motion conversion mechanism 50. The output end of the motion conversion mechanism 50 can act on the retainer 401 so that the retainer 401 has a tendency to separate the intermediate transmission component 402 from the outer ring transmission component 10 and the inner ring transmission component 20, so as to ensure that when the power output end is abnormally reversed, the intermediate transmission component 402 is separated from the outer ring transmission component 10 and the inner ring transmission component 20, and the inner ring transmission component 20 idles.

[0059] exist Figure 2In the example shown, the inner ring transmission member 20 is provided with a wedge-shaped groove 30, which has a wedge-tightening end 301 and a disengaging end 302. Along the clockwise reverse direction of the outer ring transmission member 10, i.e., from the wedge-tightening end 301 to the disengaging end 302 of the wedge-shaped groove 30, the distance between the inner wall of the wedge-shaped groove 30 and the intermediate transmission member 402 gradually increases. When it is not necessary to transmit power from the inner ring transmission member 20 to the outer ring transmission member 10, the intermediate transmission member 402 is located at the disengaging end 302 of the wedge-shaped groove 30, and the intermediate transmission member 402, the outer ring transmission member 10, and the inner ring transmission member 20 are in a disengaged state. When it is necessary to transmit power from the outer ring transmission member 10 to the inner ring transmission member 20, the intermediate transmission member 402 is located at the wedge-tightening end 301 of the wedge-shaped groove 30, and the intermediate transmission member 402, the outer ring transmission member 10, and the inner ring transmission member 20 are in a wedge-tightening state to facilitate power transmission.

[0060] by Figure 2 Taking the example shown, the outer ring transmission component 10 is set as the power input end, and the inner ring transmission component 20 is set as the power output end. The four working modes of the transmission device 902 are:

[0061] 1) The first working mode is the normal drive mode of the power source. When the power source directly or indirectly drives the outer ring transmission component 10 to rotate counterclockwise, the intermediate transmission component 402 can move to the wedge end 301 of the wedge groove 30. Under the action of the wedge groove 30, the intermediate transmission component 402 wedges tightly with the outer ring transmission component 10 and the inner ring transmission component 20, so that the outer ring transmission component 10 transmits power to the inner ring transmission component 20 through the intermediate transmission component 402 to realize power transmission.

[0062] 2) The second working mode is the power source failure separation mode. When the outer ring transmission component 10 rotates clockwise in the opposite direction under unexpected circumstances, the intermediate transmission component 402 can move to the disengagement end 302 of the wedge groove 30. The intermediate transmission component 402 separates from the outer ring transmission component 10 and the inner ring transmission component 20, and the outer ring transmission component 10 rotates idly.

[0063] 3) The third working mode is abnormal forward rotation of the power output end. When the inner ring transmission component 20 rotates counterclockwise under unexpected circumstances, the intermediate transmission component 402 can move to the disengagement end 302 of the wedge groove 30. The intermediate transmission component 402 separates from the outer ring transmission component 10 and the inner ring transmission component 20, and the outer ring transmission component 10 rotates idly.

[0064] 4) The fourth working mode is the abnormal reversal of the power output end. When the inner ring transmission component 20 rotates clockwise in an unexpected situation, the intermediate transmission component 402 has a tendency to move to the wedge end 301 of the wedge groove 30 under the action of the inner ring transmission component 20. In order to prevent the intermediate transmission component 402 from moving to the wedge end 301 of the wedge groove 30, the transmission device 902 provided in this application also includes a motion conversion mechanism 50. The output end of the motion conversion mechanism 50 can act on the retainer 401 so that the retainer 401 has a tendency to separate the intermediate transmission component 402 from the outer ring transmission component 10 and the inner ring transmission component 20, so as to ensure that when the power output end is abnormally reversed, the intermediate transmission component 402 is separated from the outer ring transmission component 10 and the inner ring transmission component 20, and the inner ring transmission component 20 idles.

[0065] In summary, the transmission device 902 provided in this application, by setting the motion conversion mechanism 50, ensures that in the normal driving mode of the power source, the intermediate transmission component 402, the outer ring transmission component 10, and the inner ring transmission component 20 are in a wedge-tight transmission state. In any other situation (power source failure separation mode, abnormal forward rotation of the power output end, and abnormal reverse rotation of the power output end), the intermediate transmission component 402, the outer ring transmission component 10, and the inner ring transmission component 20 are in a separated state, avoiding abnormal power transmission, thereby achieving the effects of reducing friction and wear, reducing energy loss, and reducing transmission knocking.

[0066] Understandably, regarding Figure 1 and Figure 2 As shown in the example, when the power input end and the power output end are interchanged, those skilled in the art can adjust the specific form of the four working modes of the transmission device 902 according to the specific situation, and adapt the setting of the motion conversion mechanism 50 to ensure that when the power output end is abnormal, the transmission device 902 is in a power separation state to avoid abnormal power transmission.

[0067] To understand the working principle of the motion conversion mechanism 50 provided in this application, the following will be combined with... Figures 3 to 5 The example shown illustrates the structure and principle of the motion conversion mechanism 50.

[0068] like Figures 3 to 4 As shown, the motion conversion mechanism 50 includes an actuating member 501, a first conversion structure 502, and a second conversion structure 503. One of the first conversion structure 502 and the second conversion structure 503 is connected to the outer ring transmission member 10 or the inner ring transmission member 20, and the other is connected to the actuating member 501. It can convert the rotation of the outer ring transmission member 10 or the inner ring transmission member 20 about the first axis into the movement of the actuating member 501 along the direction of the first axis. When the actuating member 501 moves to the state of abutting against the retainer 401, the retainer 401 has a tendency to separate the intermediate transmission member 402 from the outer ring transmission member 10 and the inner ring transmission member 20.

[0069] exist Figure 3 In the example shown, the first conversion structure 502 has an internal thread centered on the first axis, and the second conversion structure 503 has an external thread that meshes with the internal thread; the external thread is provided on the inner ring transmission member 20, and the internal thread is provided on the actuating member 501.

[0070] In one embodiment, it is assumed that in Figure 3 In the transmission device 902 shown, the wedge-shaped groove 30 is provided on the outer ring transmission member 10, and the outer ring transmission member 10 is the power input end, while the inner ring transmission member 20 is the power output end. Figure 3 When the transmission device 902 shown rotates abnormally at the power output end, the working principle of the motion conversion mechanism 50 is as follows: 1) When the inner ring transmission member 20 rotates clockwise, the intermediate transmission member 402 has a tendency to move to the wedge end 301 of the wedge groove 30. Under the meshing action of the external thread and the internal thread, the rotation of the inner ring transmission member 20 around the first axis will be converted into the movement of the action member 501 along the direction of the first axis. Figure 3 In the middle, the actuator 501 moves to the right and abuts against the end face of the retainer 401, so that the retainer 401 will not rotate with the inner ring drive member 20. This causes the intermediate drive member 402 on the retainer 401 to tend to move to the disengagement end 302 of the wedge groove 30, preventing the inner ring drive member 20 from driving the outer ring drive member 10 to rotate. 2) When the inner ring drive member 20 rotates counterclockwise, on the one hand, the intermediate drive member 402 tends to move to the disengagement end 302 of the wedge groove 30; on the other hand, under the meshing action of the external and internal threads, the rotation of the inner ring drive member 20 around the first axis is converted into the movement of the actuator 501 along the first axis direction, corresponding to... Figure 3 In the middle, the actuator 501 moves to the left and disengages from the end face of the retainer 401, and the intermediate transmission component 402 moves smoothly to the disengagement end 302 of the wedge groove 30, thereby achieving power separation.

[0071] exist Figure 4 In the example shown, the first conversion structure 502 has an internal thread centered on a first axis, and the second conversion structure 503 has an external thread that meshes with the internal thread. The internal thread is provided on the outer ring transmission member 10, and the external thread is provided on the actuating member 501. When the internal thread is provided on the outer ring transmission member 10, the outer ring transmission member 10 includes a first outer ring portion 101 and a second outer ring portion 102 disposed axially with the first outer ring portion 101. The first outer ring portion 101 can cooperate with the intermediate transmission member 402, and the inner sidewall of the second outer ring portion 102 is used to provide the internal thread. Figure 4 The working principle of the example motion conversion mechanism 50 and Figure 3 The working principle of the motion conversion mechanism 50 in the example is basically the same, and will not be described again here.

[0072] Whether Figure 3 The example shown is still Figure 4 In the example shown, each of the actuating components 501 includes a first mating part 5011, a second mating part 5012, and an actuating part 5013. The first mating part 5011 is used to slide with the housing 904 along the first axis. The second mating part 5012 is used to cooperate with the inner ring drive member 20 or the outer ring drive member 10 through the motion conversion mechanism 50. The actuating part 5013 is used to abut against the cage 401 to limit the rotation of the cage 401, so that the cage 401 has a tendency to separate the intermediate drive member 402 from the outer ring drive member 10 and the inner ring drive member 20.

[0073] In some embodiments, the housing 904 has a guide groove extending along a first axis, and the first mating portion 5011 of the actuator 501 has a guide bar extending along the first axis, the guide bar being slidably mounted in the guide groove. This arrangement allows the actuator 501 to move only relative to the housing 904 along the first axis, and not to rotate relative to the housing 904 about the first axis.

[0074] In other embodiments, the housing 904 has a guide bar extending along a first axis, and the first mating portion 5011 of the actuator 501 has a guide groove extending along a first direction, with the guide bar slidably mounted in the guide groove. This arrangement allows the actuator 501 to move only relative to the housing 904 along the first axis direction, but not to rotate relative to the housing 904 about the first axis.

[0075] It is understood that the first conversion structure 502 and the second conversion structure 503 are not limited to the above-mentioned scheme of external thread and internal thread meshing. They can also be gear and rack mechanism, cam mechanism, crank and slider mechanism, connecting rod mechanism, etc. Any mechanism that can convert rotation around the first axis direction into movement along the first axis direction is acceptable. Electromechanical control can also be used to realize the movement of the actuator 501 along the first axis direction. That is, by electronically monitoring the relative motion state of the outer ring transmission member 10 and the inner ring transmission member 20, more flexible position control of the cage 401 can be achieved by electronic control. No restrictions are imposed here.

[0076] For example, the first conversion structure 502 has a helical groove centered on the first axis, and the second conversion structure 503 has a slider that moves along the first axis; the helical groove is provided on the outer ring transmission member 10, one end of the slider is slidably engaged with the helical groove, and the other end is connected to the actuating member 501; or, the helical groove is provided on the inner ring transmission member 20, one end of the slider is slidably engaged with the helical groove, and the other end is connected to the actuating member 501. When the outer ring transmission member 10 or the inner ring transmission member 20 rotates around the first axis, the helical groove rotates synchronously around the first axis, and the slider can move along the first axis under the action of the helical groove. The cooperation between the helical groove and the slider can convert the rotation around the first axis into movement along the first axis.

[0077] For example, the first conversion structure 502 has a gear centered on a first axis, and the second conversion structure 503 has a rack extending along the first axis; the gear is connected to the outer ring transmission member 10 via a bevel gear set, which makes the rotation axis of the gear perpendicular to the first axis, and the rack is connected to the actuating member 501; or, the gear is connected to the inner ring transmission member 20 via a bevel gear set, which makes the rotation axis of the gear perpendicular to the first axis, and the rack is connected to the actuating member 501. The outer ring transmission member 10 is configured as the power input end, and the inner ring transmission member 20 is configured as the power output end. When the outer ring transmission member 10 or the inner ring transmission member 20 rotates around the first axis, the gear can rotate around a center line perpendicular to the first axis, and the meshing of the gear and rack converts the power into the movement of the rack along the first axis.

[0078] It is worth noting that, regardless of the form of the first conversion structure 502 and the second conversion structure 503, after the actuating element 501 completes the action of contacting or separating from the cage 401, the actuating element 501 should be able to stop moving along the first axis direction, that is, the motion conversion mechanism 50 should have the function of stopping the conversion motion when overtravel occurs.

[0079] Taking the scheme of internal and external thread engagement as an example, after the actuator 501 completes the action of contacting or separating from the cage 401, the actuator 501 should be able to stop moving along the first axis direction. The implementation method is as follows:

[0080] 1) By calculating and setting a suitable effective thread length, after overtravel, there is no effective engagement between the threads of the inner ring transmission component 20 (outer ring transmission component 10) and the actuator 501, thereby achieving the overtravel stop function. For example, the actuator 501 has a first position spaced apart from the retainer 401 and a second position abutting against the retainer 401. When the actuator 501 is in the first position, the minimum distance between the actuator 501 and the retainer 401 is D1, and the stroke of the actuator 501 is greater than D1 and less than 1.1D1.

[0081] 2) The thread of the outer ring transmission component 10 is a first bushing with an internal thread. When the actuator 501 overtravels, frictional sliding occurs between the first bushing of the outer ring transmission component 10 and the outer ring transmission component 10, thus realizing the overtravel stop function.

[0082] 3) such as Figure 5 As shown, the inner ring transmission component 20 has a second bushing with an external thread (i.e., the second conversion structure 503), and the first conversion structure 502 has an internal thread on the actuating component 501. When the actuating component 501 overtravels, frictional sliding occurs between the second bushing of the inner ring transmission component 20 and the inner ring transmission component 20, thus realizing the overtravel stop function.

[0083] In summary, the transmission device 902 provided in this application, by setting a motion conversion mechanism 50 and utilizing the first conversion structure 502 and the second conversion structure 503, can convert the rotation of the outer ring transmission member 10 or the inner ring transmission member 20 around the first axis into the movement of the actuating member 501 along the first axis. This allows the actuating member 501 to have a contact friction state abutting against the retainer 401 and a non-contact state separated from the retainer 401, ensuring power separation and reducing transmission knocking when the transmission device 902 rotates abnormally at the power output end.

[0084] Compared to existing technologies where frictional contact exists in all operating modes, in this application, the friction between the cage 401 and the actuator 501 only exists when the inner ring drive component 20 rotates in the opposite direction. In the commonly used normal driving mode, there is no contact between the cage 401 and the actuator 501, which reduces the contact force attenuation and abrasive contamination caused by frictional wear. Furthermore, the reverse operation of the inner ring drive component 20 is rarely used in most applications. Therefore, frictional contact can be effectively reduced, greatly extending the product's service life and improving its reliability.

[0085] This application also provides a drive unit 900, such as Figure 6 As shown, by applying the aforementioned transmission device 902, the drive unit 900 can ensure the unidirectionality of power transmission, improve the reliability and stability of unidirectional transmission, and reduce or avoid reverse power transmission at the power output end.

[0086] This application also provides a power-assisted bicycle, such as Figure 7 As shown, by applying the aforementioned drive unit 900, this electric bicycle can reduce or avoid noise and abnormal sounds caused by the wobbling of the chainring spline sleeve 700, thereby improving the rider's riding experience.

[0087] refer to Figures 6 to 7As shown, the electric bicycle provided in this application mainly includes a frame 100, a front wheel 200, a rear wheel 300, pedals 400, cranks 500, a crankshaft 600, a chainring, a chainring spline sleeve 700, a drive bar 800, and a drive unit 900. The front wheel 200 and rear wheel 300 are located at the front and rear of the frame 100, respectively. The drive unit 900 is mounted in the middle of the frame 100 and serves as the power source for the electric bicycle. This electric bicycle typically has two riding modes: manual mode and assisted mode. In manual mode, the drive unit 900 is off. The manual transmission path is as follows: the riding power is transmitted from the pedals 400 to the cranks 500, then from the cranks 500 to the crankshaft 600, then from the crankshaft 600 to the chainring spline sleeve 700, then from the chainring spline sleeve 700 to the chainring, and finally from the chainring to the rear wheel 300 via the drive bar 800, thus propelling the bicycle forward. In power-assisted mode, the drive unit 900 is activated and transmits power to the chainring spline sleeve 700, which then transmits it to the chainring, and finally to the rear wheel 300 via the drive bar 800, thus achieving electric power assistance.

[0088] The drive unit 900 provided in this application includes an assist motor 901 and a transmission device 902. The transmission device 902 includes a housing 904, an outer ring transmission component 10, a transmission assembly 40, an inner ring transmission component 20, and a motion conversion mechanism 50. The outer ring transmission component 10, the transmission assembly 40, and the inner ring transmission component 20 are all disposed within the housing 904. The outer diameter of the inner ring transmission component 20 is smaller than the inner diameter of the outer ring transmission component 10. The transmission assembly 40 is located between the outer ring transmission component 10 and the inner ring transmission component 20. The transmission assembly 40 includes a cage 401 and an intermediate transmission member 402. The cage 401 is annular and located between the outer ring transmission member 10 and the inner ring transmission member 20. The cage 401 has multiple accommodating cavities arranged circumferentially therein, and each cavity is provided with an intermediate transmission member 402. The intermediate transmission member 402 is wedged with the outer ring transmission member 10 and the inner ring transmission member 20 to achieve power rotation, and the intermediate transmission member 402 is disengaged from the outer ring transmission member 10 and the inner ring transmission member 20 to achieve power separation. The output end of the motion conversion mechanism 50 can act on the cage 401 to make the cage 401 have a tendency to separate the intermediate transmission member 402 from the outer ring transmission member 10 and the inner ring transmission member 20. This ensures that when the power output end reverses abnormally, the intermediate transmission member 402 separates from the outer ring transmission member 10 and the inner ring transmission member 20, and the inner ring transmission member 20 idles.

[0089] In the example of the electric bicycle, the outer ring drive component 10 is configured as the power input end, and the inner ring drive component 20 is configured as the power output end. During power transmission, the outer ring drive component 10 directly or indirectly receives the power output from the electric motor 901. The outer ring drive component 10 indirectly receives the power output from the electric motor 901 through the transmission gear 903, and transmits this power to the inner ring drive component 20 through the intermediate drive component 402. Finally, the inner ring drive component 20 transmits the power to the chainring spline sleeve 700. The inner ring drive component 20 can be an integral part of the chainring spline sleeve 700, or it can be an independent structure connected to the chainring spline sleeve 700 via a transmission structure; no limitation is imposed here.

[0090] To facilitate understanding of the application of the transmission device 902 provided in this application in the drive unit 900 of the electric bicycle, the working principle of the transmission device 902 will be explained below in conjunction with the motion state of the electric bicycle:

[0091] In the initial state, the intermediate transmission component 402, the outer ring transmission component 10, and the inner ring transmission component 20 of the transmission device 902 are in a disengaged state.

[0092] 1) When the electric bicycle is in assist mode, the assist motor 901 starts and drives the outer ring transmission component 10 to rotate counterclockwise. The power from the outer ring transmission component 10 needs to be transmitted to the inner ring transmission component 20 so that the inner ring transmission component 20 drives the chainring spline sleeve 700 to rotate, thus achieving assist mode. Therefore, during assist mode riding, the transmission device 902 is in normal power source drive mode, the motion conversion mechanism 50 is not activated, and the intermediate transmission component 402, outer ring transmission component 10, and inner ring transmission component 20 are in a wedged state.

[0093] 2) When the power assist motor 901 malfunctions and drives the outer ring transmission component 10 to rotate clockwise in the opposite direction, it is not necessary to transmit the power of the outer ring transmission component 10 to the inner ring transmission component 20. Therefore, during this process, the transmission device 902 is in the abnormal power source separation mode, the motion conversion mechanism 50 does not work, and the intermediate transmission component 402, the outer ring transmission component 10 and the inner ring transmission component 20 are in a disengaged state, and power is not transmitted.

[0094] 3) When the chainring spline sleeve 700 rotates counterclockwise under external force, it transmits power to the inner ring drive component 20. At this time, it is not necessary to transmit power from the inner ring drive component 20 to the outer ring drive component 10. Therefore, during this process, the transmission device 902 is in an abnormal forward rotation state at the power output end, the motion conversion mechanism 50 is not activated, and the intermediate drive component 402, outer ring drive component 10, and inner ring drive component 20 are disengaged, and power is not transmitted.

[0095] 4) When the chainring spline sleeve 700 rotates clockwise under external force, it transmits power to the inner ring drive member 20. At this time, it is not necessary to transmit the power of the inner ring drive member 20 to the outer ring drive member 10. Therefore, during this process, the transmission device 902 is in a reverse abnormality at the power output end. The motion conversion mechanism 50 is activated, converting the rotation of the inner ring drive member 20 around the first axis into the movement of the actuating member 501 along the first axis. When the actuating member 501 moves to the state of contact with the retainer 401, the retainer 401 has a tendency to separate the intermediate drive member 402 from the outer ring drive member 10 and the inner ring drive member 20, so that the intermediate drive member 402, the outer ring drive member 10 and the inner ring drive member 20 are in a disengaged state and power is not transmitted.

[0096] Therefore, the electric bicycle provided in this application can improve the reliability and stability of unidirectional power transmission, thereby reducing or avoiding the abnormal noise problem caused by the wobbling of the chainring spline sleeve 700, improving the rider's riding experience, and can also be used in other occasions that require unidirectional power transmission, without limitation.

[0097] Obviously, the above embodiments of this application are merely examples for clear illustration and are not intended to limit the implementation of this application. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the scope of protection of the claims of this application.

Claims

1. A transmission device, characterized in that, include: Outer ring transmission component (10); The inner ring transmission component (20) is coaxially arranged with the outer ring transmission component (10) centered on the first axis. The transmission assembly (40) includes an intermediate transmission member (402) and a retainer (401). The retainer (401) is located between the outer ring transmission member (10) and the inner ring transmission member (20). The retainer (401) has a plurality of receiving cavities arranged circumferentially therebetween, and the intermediate transmission member (402) is provided in each of the receiving cavities. The motion conversion mechanism (50) includes an actuating element (501), a first conversion structure (502), and a second conversion structure (503). One of the first conversion structure (502) and the second conversion structure (503) is connected to the outer ring transmission element (10) or the inner ring transmission element (20), and the other is connected to the actuating element (501). It is capable of converting the rotation of the outer ring transmission element (10) or the inner ring transmission element (20) about a first axis into the movement of the actuating element (501) along the direction of the first axis. When the actuator (501) moves to abut against the retainer (401), the retainer (401) has a tendency to separate the intermediate transmission member (402) from the outer ring transmission member (10) and the inner ring transmission member (20).

2. The transmission device according to claim 1, characterized in that, The first conversion structure (502) has an internal thread centered on a first axis, and the second conversion structure (503) has an external thread that engages with the internal thread; The internal thread is provided on the outer ring transmission member (10), and the external thread is provided on the actuating member (501); or, the external thread is provided on the inner ring transmission member (20), and the internal thread is provided on the actuating member (501).

3. The transmission device according to claim 2, characterized in that, The actuator (501) has a first position spaced apart from the retainer (401) and a second position abutting against the retainer (401). When the actuator (501) is in the first position, the minimum distance between the actuator (501) and the retainer (401) is D1, and the stroke of the actuator (501) is greater than D1 and less than 1.1D1.

4. The transmission device according to claim 2, characterized in that, The first conversion structure (502) is a first bushing with the internal thread, the first bushing is disposed on the actuating member (501), or the first bushing is disposed on the outer ring transmission member (10). And / or, the second conversion structure (503) is a second bushing with external threads, the second bushing being disposed on the inner ring transmission member (20), or, the second bushing being disposed on the actuating member (501).

5. The transmission device according to claim 2, characterized in that, When the internal thread is provided on the outer ring transmission member (10), the outer ring transmission member (10) includes a first outer ring portion (101) and a second outer ring portion (102) arranged axially with the first outer ring portion (101). The first outer ring portion (101) can cooperate with the intermediate transmission member (402), and the inner sidewall of the second outer ring portion (102) is used to provide the internal thread.

6. The transmission device according to claim 1, characterized in that, The first conversion structure (502) has a spiral groove centered on a first axis, and the second conversion structure (503) has a slider that moves along the first axis; The spiral groove is provided on the outer ring transmission member (10), and the slider is connected to the actuating member (501); or, the spiral groove is provided on the inner ring transmission member (20), and the slider is connected to the actuating member (501).

7. The transmission device according to claim 1, characterized in that, The first conversion structure (502) has a gear centered on a first axis, and the second conversion structure (503) has a rack extending along the first axis; The gear is connected to the outer ring transmission member (10) via a bevel gear set, the bevel gear set being used to make the rotation axis of the gear perpendicular to the first axis, and the rack being connected to the actuating member (501); or, the gear is connected to the inner ring transmission member (20) via a bevel gear set, the bevel gear set being used to make the rotation axis of the gear perpendicular to the first axis, and the rack being connected to the actuating member (501).

8. The transmission device according to any one of claims 1-7, characterized in that, One of the outer ring drive member (10) and the inner ring drive member (20) is provided with a wedge groove (30). A plurality of wedge grooves (30) are arranged at intervals along the circumference of the retainer (401) and correspond one-to-one with the intermediate drive member (402). The wedge groove (30) has a wedge-tightening end (301) and a disengaging end (302). When the intermediate transmission member (402) is located at the wedge end (301) of the wedge groove (30), the outer ring transmission member (10), the intermediate transmission member (402) and the inner ring transmission member (20) are in a wedge-tight state. When the intermediate transmission member (402) is located at the disengagement end (302) of the wedge groove (30), the outer ring transmission member (10), the intermediate transmission member (402) and the inner ring transmission member (20) are in a disengaged state.

9. The transmission device according to claim 8, characterized in that, The outer ring drive member (10) is configured as a power input end, and the inner ring drive member (20) is configured as a power output end.

10. A driving unit, characterized in that, Includes the transmission device as described in any one of claims 1-9.

11. A power-assisted bicycle, characterized in that, Includes the drive unit as described in claim 10.

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