Middle motor, five-way structure of middle motor and power-assisted bicycle

Abstract

The utility model discloses a centrally-mounted motor, a five-way structure of the centrally-mounted motor and a power-assisted bicycle. The five-way structure of the centrally-mounted motor comprises a five-way shaft, an output gear, a clutch sleeve and a strain sleeve, and the strain sleeve is connected to the periphery of the five-way shaft; the output gear comprises a hub part and a gear part, the gear part is located on the outer ring of the hub part, and the side, away from the gear part, of the hub part is in transmission connection with the five-way shaft. The clutch sleeve is arranged on the periphery of the five-way shaft in a sleeving mode and is in transmission connection with the hub part, the clutch sleeve is provided with a first end face facing the strain sleeve in the axial direction of the five-way shaft, and a first tooth-shaped structure is arranged on the first end face; the strain sleeve is provided with a second end face facing the first end face, and the second end face is provided with a second tooth-shaped structure. The first tooth-shaped structure and the second tooth-shaped structure can be matched to form a torque transmission mechanism used for transmitting torque. According to the jaw clutch, the clutch sleeve and the strain sleeve are matched to form the jaw clutch with the end face transmitting torque, and one-way large torque transmission between the output gear and the five-way shaft can be achieved.

Description

TECHNICAL FIELD

[0001] The utility model relates to electric bicycle technical field, especially a kind of middle motor and its five-way structure, and power-assisted bicycle. BACKGROUND

[0002] In the transmission system of bicycle, the power transmission structure between five-way shaft and output gear is extremely critical. At present, the industry generally uses ratchet pawl or one-way roller clutch to realize transmission.

[0003] Ratchet pawl transmits power by ratchet pawl and ratchet wheel cooperation, and it is widely used in traditional bicycle because of its simple structure and low cost. However, ratchet pawl transmission has the disadvantage of small torque transmission, and when actual riding encounters large torque conditions such as climbing, heavy load and sprint, the pawl and ratchet tooth surface are single-point or line contact, and the maximum bearing torque is not more than 300N.m, and it is easy to wear and tear, and the pawl may be broken in severe cases, resulting in failure of the transmission system.

[0004] One-way roller clutch transmits torque by wedge of roller and inner and outer rings, and the contact mode changes to surface contact, so the transmission torque is improved, and the limit torque can reach 400N.m-500N.m. However, when facing higher torque, especially when the torque is greater than or equal to 600N.m, the roller will be plastic deformed, resulting in failure of the clutch. Moreover, one-way roller clutch transmission is sensitive to working environment, and oil stains and sand invasion will affect the wedge effect.

[0005] As an improvement, the prior art increases the number of pawls and optimizes the roller material to improve torque transmission, but it cannot break through the structural limitation. With the rise of electric power-assisted bicycles, freight bicycles and other vehicles, the requirement for transmission system torque is gradually increasing, and traditional ratchet pawl and one-way roller clutch cannot meet the use requirements. INVENTION CONTENTS

[0006] The utility model aims to provide a kind of middle motor and its five-way structure, and power-assisted bicycle, solve the problem that the transmission torque is small and easy to fail in the occasion needing to transmit large torque in the prior art that bicycle five-way shaft and output gear are driven by ratchet pawl or one-way roller clutch.

[0007] The above-mentioned purpose of the utility model can be realized by using the following technical solutions:

[0008] The utility model provides a kind of five-way structure of middle motor, including five-way shaft, output gear, clutch cover and strain sleeve, the strain sleeve is connected in the five-way shaft outer periphery;The output gear includes hub portion and gear portion, the gear portion is located the hub portion outer circle, the side of the hub portion away from the gear portion is connected with the five-way shaft transmission, the clutch cover is sleeved in the five-way shaft outer periphery, and is connected with the hub portion transmission, the clutch cover has the first end surface along the five-way shaft axial direction towards the strain sleeve, and first tooth profile structure is arranged on the first end surface;The strain sleeve has the second end surface towards the first end surface, and second tooth profile structure is arranged on the second end surface;The first tooth profile structure and the second tooth profile structure can cooperate to form the transmission mechanism for transmitting torque.The clutch cover and the strain sleeve cooperate to form the toothed clutch of end surface transmission torque, can realize the one-way large torque transmission between the output gear and the five-way shaft, effectively improve the load capacity of five-way structure, reduce the slip failure risk of clutch under the condition of large torque, and obtain better axial size compactness.

[0009] Preferably, the clutch cover has a connecting portion and a shoulder portion, the connecting portion is at least partially located inside the hub portion and is in transmission connection with the hub portion, the shoulder portion has a radial dimension larger than the connecting portion, and the shoulder portion is completely located outside the hub portion, and the first end surface is located on the shoulder portion. The shoulder structure is formed by the connecting portion and the shoulder portion to obtain better assembly and torque transmission effect.

[0010] Preferably, the first tooth profile structure is formed on the end surface of the side of the shoulder portion away from the connecting portion, and the shoulder portion and the end surface of the output gear have a preset gap, and the preset gap is larger than the tooth height of the first tooth profile structure in the axial direction of the five-way shaft, so as to ensure that the clutch cover can normally disengage from the strain sleeve.

[0011] Preferably, a first inner hole and a first step surface are arranged in the hub portion, a first deep groove ball bearing is arranged in the first inner hole, the outer ring of the first deep groove ball bearing is in interference fit with the hole wall of the first inner hole, the inner hole of the first deep groove ball bearing is in clearance fit with the five-way shaft, and the end surface of the first deep groove ball bearing is in positioning fit with the first step surface. The first deep groove ball bearing is arranged between the output gear and the five-way shaft to improve the support stiffness of the output gear and ensure the running stability and service life of the output gear.

[0012] Preferably, an elastic member is arranged between the clutch cover and the first deep groove ball bearing, the elastic member is used to provide elastic force to the clutch cover, so that the clutch cover moves in the axial direction of the five-way shaft, to realize and maintain the cooperation between the clutch cover and the strain sleeve, and ensure torque transmission.

[0013] Preferably, the first tooth structure comprises a plurality of first teeth evenly spaced along the circumferential direction of the clutch sleeve, each of the first teeth having a first tooth front surface perpendicular to the end surface of the clutch sleeve and a first tooth inclined surface having an acute angle with the end surface of the clutch sleeve; the second tooth structure comprises a plurality of second teeth evenly spaced along the circumferential direction of the strain sleeve, each of the second teeth having a second tooth front surface perpendicular to the end surface of the strain sleeve and a second tooth inclined surface having an acute angle with the end surface of the strain sleeve; the plurality of first teeth can correspondingly fit with the plurality of second teeth to form the torque transmission mechanism. In this way, the torque contact area is ensured, and the service life and reliability of the clutch are improved.

[0014] Specifically, when the five-way shaft rotates in a first direction, the first tooth front surfaces of the plurality of first teeth abut against the second tooth front surfaces of the plurality of second teeth to transmit torque, and the clutch formed by the clutch sleeve and the strain sleeve is in a combined state; when the five-way shaft rotates in a second direction, the first tooth inclined surfaces of the plurality of first teeth and the second tooth inclined surfaces of the plurality of second teeth move relatively, the clutch sleeve moves axially along the five-way shaft until the plurality of first teeth and the plurality of second teeth correspondingly disengage, torque is disconnected, and the clutch formed by the clutch sleeve and the strain sleeve is in a disconnected state; the first direction is opposite to the second direction.

[0015] Preferably, the hub portion is provided with a second inner hole and a second stepped surface, the second inner hole is provided with a needle bearing, the outer ring of the needle bearing is in interference fit with the hole wall of the second inner hole, the inner hole of the needle bearing is in clearance fit with the five-way shaft, and the end surface of the needle bearing is in positioning fit with the second stepped surface. By arranging the needle bearing between the output gear and the five-way shaft, the support stiffness of the output gear is further improved, and the running stability and service life of the output gear are improved.

[0016] Preferably, the hub portion is provided with a third inner hole, the third inner hole is located at one end of the output gear away from the clutch sleeve, and the third inner hole is provided with a sealing element abutting between the output gear and the five-way shaft to prevent external dust and water vapor from entering the inside of the output gear and causing damage.

[0017] Preferably, the hub portion is rotationally connected with the housing through a second deep groove ball bearing, and the output gear is axially limited on the five-way shaft by the second deep groove ball bearing and the first deep groove ball bearing, and the second deep groove ball bearing at least partially overlaps the needle bearing along the axial direction of the five-way shaft.

[0018] Preferably, the second deep groove ball bearing is arranged at a position corresponding to the middle part of the hub portion and the needle bearing along the axial direction of the five-way shaft, so that the system as a whole has better rigidity and stability.

[0019] Another object of the present application is to provide a middle motor comprising the five-way structure of the middle motor as described above.

[0020] The present application further provides a power-assisted bicycle comprising the middle motor as described above.

[0021] The five-way structure of the middle motor provided by the present application comprises a five-way shaft, an output gear, a clutch sleeve and a strain sleeve, the strain sleeve is connected outside the five-way shaft, the hub of the output gear is drivingly connected with the strain sleeve through the clutch sleeve, the clutch sleeve and the strain sleeve cooperatively form a jaw clutch for end face torque transmission, one-way large torque transmission between the output gear and the five-way shaft is realized, the load capacity of the five-way structure is effectively improved, the risk of slipping failure of the clutch under large torque condition is reduced, and better axial size compactness is obtained. BRIEF DESCRIPTION OF DRAWINGS

[0022] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed in the embodiment description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0023] Figure 1 FIG. 1 is a front view of the five-way structure of the middle motor provided in the embodiments of the present application in a strain sleeve and clutch sleeve disengaged state;

[0024] Figure 2 FIG. 2 is a sectional view of the five-way structure of the middle motor provided in the embodiments of the present application in a strain sleeve and clutch sleeve disengaged state;

[0025] Figure 3 FIG. 3 is a sectional view of the five-way structure of the middle motor provided in the embodiments of the present application in a strain sleeve and clutch sleeve combined state;

[0026] Figure 4 Figure 1 is a schematic view of a five-way shaft according to the present application. Figure 3 Figure 1 is a schematic view of a five-way shaft according to the present application.

[0027] BRIEF DESCRIPTION OF DRAWINGS

[0028] 1. five-way shaft

[0029] 2. output gear; 21. first stepped surface; 22. second stepped hole surface

[0030] 3. clutch cover; 31. connecting portion; 32. shoulder portion; 33. first tooth; 331. first tooth front surface; 332. first tooth inclined surface

[0031] 4. strain sleeve

[0032] 5. first deep groove ball bearing

[0033] 6. elastic member

[0034] 7. needle bearing

[0035] 8. sealing member

[0036] 9. second deep groove ball bearing

[0037] d. preset gap; h. tooth height DETAILED DESCRIPTION

[0038] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0039] As Figures 1 to 3As shown in the utility model provides a kind of five-way structure of middle motor, including five-way shaft 1, output gear 2, clutch cover 3 and strain sleeve 4, output gear 2 is driven by middle motor, strain sleeve 4 is connected in the outer periphery of five-way shaft 1;Output gear 2 includes hub portion and gear portion, gear portion is located the outer circle of hub portion, and the side of hub portion, which is away from gear portion, is drivingly connected with five-way shaft 1;Clutch cover 3 is sleeved on the outer periphery of five-way shaft 1, and is drivingly connected with hub portion, clutch cover 3 has first end face towards strain sleeve 4 along the axial direction of five-way shaft 1, and first end face is provided with first tooth profile structure;Strain sleeve 4 has second end face towards first end face, and second end face is provided with second tooth profile structure;First tooth profile structure and second tooth profile structure can cooperate to form torque transmission mechanism for transmitting torque.In this way, clutch cover 3 and strain sleeve 4 cooperate to form face transmission torque of toothed clutch, which can realize one-way large torque transmission between output gear 2 and five-way shaft 1, effectively improve the carrying capacity of five-way structure, reduce the risk of slipping failure of clutch under large torque condition, and obtain better axial size compactness.

[0040] According to a preferred embodiment of the utility model, five-way shaft 1 is a hollow shaft to meet the lightweight demand and torque transmission demand under the premise of ensuring strength.

[0041] According to a preferred embodiment of the utility model, the end of the hub portion of output gear 2, which is close to clutch cover 3, is provided with first internal spline, and the outer wall of clutch cover 3 is provided with first external spline matched with the first internal spline.Output gear 2 and clutch cover 3 are drivingly connected through spline structure, which has the advantages of good universality, easy processing and detachability.

[0042] According to a preferred embodiment of the utility model, the inner wall of strain sleeve 4 is provided with second internal spline, and the outer wall of five-way shaft 1 is provided with second external spline matched with the second internal spline.Strain sleeve 4 and five-way shaft 1 are drivingly connected through spline structure, which has the advantages of good universality, easy processing and detachability.

[0043] According to a preferred embodiment of the utility model, in combination with Figure 4 As shown in the utility model, clutch cover 3 has connecting portion 31 and shoulder portion 32, connecting portion 31 is at least partially located on the inner side of hub portion and is drivingly connected with hub portion, the radial dimension of shoulder portion 32 is greater than that of connecting portion 31, and shoulder portion 32 is completely located on the outer side of hub portion, and first end face is located on shoulder portion 32.A shoulder structure is formed by connecting portion 31 and shoulder portion 32 to obtain better assembly and torque transmission effect.

[0044] According to the preferred embodiment of the utility model, the first tooth structure is formed on the side end face of the shoulder part 32 away from the connecting part 31, the shoulder part 32 and the end face of the output gear 2 have a preset gap d, the preset gap d is greater than the tooth height h of the first tooth structure along the axial direction of the five-way shaft 1, that is, the preset gap d between the shoulder part 32 and the end face of the output gear 2 is greater than the length of the first tooth structure along the axial direction of the five-way shaft 1, so as to ensure that the clutch cover 3 can normally separate from the strain sleeve 4.

[0045] According to the preferred embodiment of the utility model, as shown in Figure 2 and Figure 3 , the first inner hole and the first step surface 21 are arranged in the hub part of the output gear 2, the first deep groove ball bearing 5 is arranged in the first inner hole, the outer ring of the first deep groove ball bearing 5 is in interference fit with the hole wall of the first inner hole, the inner hole of the first deep groove ball bearing 5 is in clearance fit with the five-way shaft 1, and the end face of the first deep groove ball bearing 5 is in positioning fit with the first step surface 21. By arranging the first deep groove ball bearing 5 between the output gear 2 and the five-way shaft 1, the support stiffness of the output gear 2 is improved, and the running stability and service life of the output gear 2 are ensured.

[0046] According to the preferred embodiment of the utility model, as shown in Figure 2 and Figure 3 , the elastic member 6 is arranged between the clutch cover 3 and the first deep groove ball bearing 5, the elastic member 6 is used for providing elastic force to the clutch cover 3, so that the clutch cover 3 moves along the axial direction of the five-way shaft 1, the cooperation between the clutch cover 3 and the strain sleeve 4 is realized and maintained, and the torque transmission is ensured.

[0047] According to the preferred embodiment of the utility model, as shown in Figure 4 , the first tooth structure includes a plurality of first teeth 33 which are uniformly distributed along the circumferential direction of the clutch cover 3, each first tooth 33 has a first tooth front surface 331 and a first tooth inclined surface 332, the first tooth front surface 331 is perpendicular to the end face of the clutch cover 3, and the first tooth inclined surface 332 has an acute angle with the end face of the clutch cover 3; the second tooth structure includes a plurality of second teeth which are uniformly distributed along the circumferential direction of the strain sleeve 4, each second tooth has a second tooth front surface and a second tooth inclined surface, the second tooth front surface is perpendicular to the end face of the strain sleeve 4, and the second tooth inclined surface has an acute angle with the end face of the strain sleeve 4; the plurality of first teeth 33 can correspondingly adhere to the plurality of second teeth to form a torque transmission mechanism. Exemplarily, the first tooth 33 and the second tooth are both designed as triangular teeth, so as to facilitate the engagement and separation of the clutch cover 3 and the strain sleeve 4, and meanwhile, the contact area between the first tooth 33 and the second tooth is relatively large when the torque is transmitted, the pressure distribution is relatively uniform, which is helpful to reduce the wear and fatigue damage of the tooth surface, improve the service life and reliability of the clutch.

[0048] Specifically, when the bottom bracket shaft 1 rotates in the first direction, under the elastic force of the elastic element 6, the first tooth faces 331 of the multiple first teeth 33 abut against the second tooth faces of the multiple second teeth and transmit torque; when the bottom bracket shaft 1 rotates in the second direction, relative movement occurs between the first tooth inclined surfaces 332 of the multiple first teeth 33 and the second tooth inclined surfaces of the multiple second teeth. Under the action of circumferential force, the second tooth inclined surfaces of the second teeth generate an axial component force perpendicular to the end face of the strain sleeve 4. Under the action of the axial component force, the clutch sleeve 3 moves axially along the bottom bracket shaft 1 and compresses the elastic element 6 until the multiple first teeth 33 disengage from the multiple second teeth; the first direction is opposite to the second direction. Figure 3 As shown, when the five-way shaft 1 rotates in the first direction (driving direction), the front surface 331 of the first tooth 33 of each first tooth 33 is in complete contact with the front surface of the second tooth of each of the multiple second teeth. At this time, the inclined surface 332 of the first tooth 33 of each of the multiple first teeth is also in complete contact with the inclined surface of the second tooth of each of the multiple second teeth, and the clutch is in the torque transmission engagement state; as shown Figure 1 and Figure 2 As shown, when the bottom bracket shaft 1 rotates in the second direction (non-driving direction), relative movement occurs between the first tooth inclined surfaces 332 of the multiple first teeth 33 and the second tooth inclined surfaces of the multiple second teeth. Under the action of circumferential force, the second tooth inclined surfaces of each second tooth generate axial component force. Multiple axial component forces act to compress the clutch sleeve 3, causing it to move axially along the bottom bracket shaft 1 and compress the elastic element 6. The contact area between the first tooth face 331 of each first tooth 33 and the corresponding second tooth face decreases. At the critical state where the first tooth face 331 of each first tooth 33 and the corresponding second tooth face do not contact, the strain sleeve 4 disengages from the clutch sleeve 3, and the clutch is in a disengaged state. Preferably, as... Figure 2 and Figure 3 As shown, the elastic element 6 abuts against the connecting portion 31 of the first deep groove ball bearing 5 and the clutch sleeve 3 to ensure the service life of the elastic element 6. Preferably, the elastic element 6 is a metal spring.

[0049] According to a preferred embodiment of the present invention, such as Figure 2 and Figure 3 As shown, the hub of the output gear 2 has a second inner hole and a second stepped surface 22. A needle roller bearing 7 is installed inside the second inner hole. The outer ring of the needle roller bearing 7 is interference-fitted with the wall of the second inner hole, the inner hole of the needle roller bearing 7 is clearance-fitted with the bottom bracket shaft 1, and the end face of the needle roller bearing 7 is positionally fitted with the second stepped surface 22. By installing the needle roller bearing 7 between the output gear 2 and the bottom bracket shaft 1, the support rigidity of the output gear 2 is further improved, thereby enhancing the smoothness of operation and the service life of the output gear 2.

[0050] According to a preferred embodiment of the present invention, such as Figure 2 and Figure 3As shown in the figure, a third inner hole is arranged in the hub portion of the output gear 2, and the third inner hole is located at the end of the output gear 2 away from the clutch sleeve 3; a sealing element 8 is arranged in the third inner hole to abut between the output gear 2 and the five-way shaft 1, so as to prevent external dust and water vapor from entering the inside of the output gear 2 and causing damage. Preferably, the sealing element 8 is an O-shaped sealing ring.

[0051] According to a preferred embodiment of the utility model, Figures 1 to 3 As shown in the figure, the hub portion of the output gear 2 is rotatably connected with the shell (not shown in the figure) through the second deep groove ball bearing 9, and the end portion of the second deep groove ball bearing 9 close to the first deep groove ball bearing 5 abuts against the stepped surface of the hub portion of the output gear 2, so that the second deep groove ball bearing 9 can realize axial limiting of the output gear 2 on the five-way shaft 1 after cooperating with the first deep groove ball bearing 5; and the hub portion of the output gear 2 is supported by the bearings on the inside and outside, which is beneficial to increase the stability. Preferably, the second deep groove ball bearing 9 at least partially overlaps the needle bearing 7 along the axial direction of the five-way shaft 1, so as to further improve the overall rigidity and stability of the system.

[0052] According to a preferred embodiment of the utility model, Figure 2 and Figure 3 As shown in the figure, the second deep groove ball bearing 9 is arranged at the position corresponding to the middle portion of the needle bearing 7 along the axial direction of the five-way shaft 1, that is, the second deep groove ball bearing 9 is arranged close to the support center of the needle bearing 7, so that the overall system obtains better rigidity and stability.

[0053] Based on the above description, the five-way structure of the middle-mounted motor provided by the utility model embodiment has the following beneficial effects:

[0054] The five-way structure of the middle-mounted motor provided by the utility model embodiment comprises a five-way shaft 1, an output gear 2, a clutch sleeve 3 and a strain sleeve 4; the strain sleeve 4 is connected outside the five-way shaft 1; the hub portion of the output gear 2 is drivingly connected with the strain sleeve 4 through the clutch sleeve 3; the clutch sleeve 3 and the strain sleeve 4 cooperatively form a jaw clutch for transmitting torque on the end face, so that one-way large torque transmission between the output gear 2 and the five-way shaft 1 can be realized, the carrying capacity of the five-way structure is effectively improved, the risk of slipping failure of the clutch under the condition of large torque is reduced, and better axial size compactness is obtained; meanwhile, the first deep groove ball bearing 5 and the needle bearing 7 are arranged between the output gear 2 and the five-way shaft 1, and the second deep groove ball bearing 9 is arranged between the hub portion of the output gear 2 and the shell, so as to improve the support rigidity, running stability and service life of the output gear 2.

[0055] Another object of the utility model is to provide a middle-mounted motor comprising the above-mentioned five-way structure of the middle-mounted motor.

[0056] The middle motor provided by the utility model can achieve the technical effects realized by the five-way structure implementation mode of the middle motor, and specific description can be made by referring to the specific description of the above implementation mode, which will not be repeated here.

[0057] The utility model also provides a power-assisted bicycle, including above-mentioned middle motor.

[0058] The power-assisted bicycle provided by the utility model can realize large torque transmission by the above-mentioned middle motor.

[0059] The above-mentioned only for several embodiments of the utility model, the person skilled in the art can make various changes or modifications to the utility model embodiments according to the content disclosed in the application file without departing from the spirit and scope of the utility model.

Claims

1. A five-way valve structure for a mid-drive motor, characterized in that, It includes a bottom bracket shaft, an output gear, a clutch sleeve, and a strain gauge sleeve, wherein the strain gauge sleeve is connected to the outer periphery of the bottom bracket shaft; The output gear includes a hub and a gear, the gear is located on the outer ring of the hub, and the side of the hub away from the gear is connected to the five-way shaft for transmission. The clutch sleeve is fitted around the outer periphery of the five-way shaft and is connected to the hub portion for transmission. The clutch sleeve has a first end face facing the strain sleeve along the axial direction of the five-way shaft, and a first tooth structure is provided on the first end face. The strain sleeve has a second end face facing the first end face, and a second toothed structure is provided on the second end face; The first tooth structure and the second tooth structure can cooperate to form a torque transmission mechanism for transmitting torque.

2. The five-way valve structure of the mid-mounted motor according to claim 1, characterized in that, The clutch sleeve has a connecting portion and a shoulder portion. The connecting portion is at least partially located inside the hub portion and is drively connected to the hub portion. The radial dimension of the shoulder portion is larger than that of the connecting portion, and the shoulder portion is completely located outside the hub portion. The first end face is located on the shoulder portion.

3. The five-way valve structure of the mid-mounted motor according to claim 2, characterized in that, The first tooth structure is formed on the end face of the shoulder away from the connecting part. There is a preset gap between the end face of the shoulder and the output gear. The preset gap is greater than the tooth height of the first tooth structure along the axial direction of the five-way shaft.

4. The five-way valve structure of the mid-mounted motor according to claim 3, characterized in that, The hub portion is provided with a first inner hole and a first stepped surface. A first deep groove ball bearing is provided in the first inner hole. The outer ring of the first deep groove ball bearing is interference-fitted with the hole wall of the first inner hole. The inner hole of the first deep groove ball bearing is clearance-fitted with the five-way shaft. The end face of the first deep groove ball bearing is positioned with the first stepped surface.

5. The five-way valve structure of the mid-mounted motor according to claim 4, characterized in that, An elastic element is provided between the clutch sleeve and the first deep groove ball bearing. The elastic element is used to provide elastic force to the clutch sleeve, so that the clutch sleeve can move axially along the bottom bracket shaft.

6. The five-way valve structure of the mid-mounted motor according to claim 5, characterized in that, The first tooth structure includes a plurality of first teeth evenly spaced along the circumferential direction of the clutch sleeve. Each first tooth has a first tooth face and a first tooth slope. The first tooth face is perpendicular to the end face of the clutch sleeve, and the first tooth slope has an acute angle with the end face of the clutch sleeve. The second tooth structure includes a plurality of second teeth evenly spaced along the circumferential direction of the strain sleeve. Each second tooth has a second tooth face and a second tooth slope. The second tooth face is perpendicular to the end face of the strain sleeve, and the second tooth slope has an acute angle with the end face of the strain sleeve. The plurality of first teeth and the plurality of second teeth can correspondingly engage to form the torque transmission mechanism.

7. The five-way valve structure of the mid-mounted motor according to claim 6, characterized in that, When the five-way shaft rotates in the first direction, the front surfaces of the first teeth of the plurality of first teeth abut against the front surfaces of the second teeth of the plurality of second teeth and transmit torque. When the five-way shaft rotates in the second direction, relative movement occurs between the first tooth inclined surfaces of the plurality of first teeth and the second tooth inclined surfaces of the plurality of second teeth, and the clutch sleeve moves axially along the five-way shaft until the plurality of first teeth and the plurality of second teeth disengage accordingly. The first direction is opposite to the second direction.

8. The five-way valve structure of the mid-mounted motor according to claim 7, characterized in that, The hub portion is provided with a second inner hole and a second stepped surface. A needle roller bearing is provided in the second inner hole. The outer ring of the needle roller bearing is interference-fitted with the hole wall of the second inner hole. The inner hole of the needle roller bearing is clearance-fitted with the five-way shaft. The end face of the needle roller bearing is positioned with the second stepped surface.

9. The five-way valve structure of the mid-mounted motor according to claim 8, characterized in that, The hub portion is provided with a third inner hole, which is located at the end of the output gear away from the clutch sleeve. A seal is provided in the third inner hole that abuts against the output gear and the five-way shaft.

10. The five-way valve structure of the mid-mounted motor according to claim 8, characterized in that, The hub is rotatably connected to the housing via a second deep groove ball bearing. The output gear is axially limited on the bottom bracket shaft by the second deep groove ball bearing and the first deep groove ball bearing. Along the axial direction of the bottom bracket shaft, the second deep groove ball bearing and the needle roller bearing at least partially overlap.

11. The five-way valve structure of the mid-mounted motor according to claim 10, characterized in that, Along the axial direction of the five-way shaft, the second deep groove ball bearing is disposed at a position corresponding to the middle of the hub portion and the needle roller bearing.

12. A mid-drive motor, characterized in that, Includes the bottom bracket structure of the mid-drive motor as described in any one of claims 1 to 11.

13. A power-assisted bicycle, characterized in that, Includes the mid-drive motor as described in claim 12.

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