Middle motor and electric bicycle

Abstract

The utility model relates to the field of middle motors for electric bicycles, in particular to a middle motor and an electric bicycle. The middle motor comprises an electric mechanism, a middle shaft, an output shaft and a ratchet wheel assembly. The output shaft and the ratchet wheel assembly are arranged on the middle shaft in a sleeving mode, the axis of the output shaft, the axis of the ratchet wheel assembly and the axis of the middle shaft are configured to be coaxial, and the ratchet wheel assembly is limited between the output shaft and the middle shaft in the radial direction of the middle shaft; the ratchet wheel assembly comprises a first ratchet wheel, a second ratchet wheel and an elastic part, the first ratchet wheel is provided with a first tooth part, and the second ratchet wheel is provided with a second tooth part; under the condition that the first tooth part and the second tooth part are meshed with each other, due to the fact that the first tooth part and the second tooth part are in face-to-face contact, the contact area of the first tooth part and the second tooth part is relatively large, the pressure intensity borne by the first tooth part and the second tooth part is small, the tooth part abrasion degree of the first tooth part and the second tooth part is relatively slow, and the reliability is higher.

Description

Technical Field

[0001] The utility model relates to the field of mid-mounted motors for electric bicycles, in particular to a mid-mounted motor and an electric bicycle. Background Art

[0002] In electric bicycles of the prior art, a mid-mounted motor generally comprises a motor, a reducer, a middle shaft, an output shaft and a one-way bearing; wherein the motor drives the output shaft via the reducer, and the middle shaft drives the output shaft via the one-way bearing, so that the motor and the middle shaft respectively serve as power sources and can selectively transmit power to the output shaft via the one-way bearing.

[0003] However, in the prior art, in order to ensure the strength of the one-way bearing between the center shaft and the output shaft, the diameter of the one-way bearing is usually selected to be relatively large, resulting in the one-way bearing of a relatively large model occupying a relatively large space in the center motor; if the diameter of the one-way bearing is relatively small, since the needle roller of the one-way bearing acts as a stopper through friction on the tooth surface of the one-way bearing, when the center motor of the prior art is used for a long time, the friction force exerted on the needle roller will cause material fatigue of the needle roller itself, causing the needle roller failure, and further resulting in insufficient load-bearing capacity of the one-way bearing with a relatively small diameter; when the load-bearing capacity of the one-way bearing is insufficient, the reliability of the one-way transmission between the center shaft and the output shaft is relatively low.

[0004] Therefore, how to improve the reliability of the one-way transmission between the center shaft and the output shaft becomes a technical problem to be solved. Utility Model Content

[0005] In order to solve the technical problem of how to improve the reliability of one-way transmission between a central shaft and an output shaft, the utility model provides a central motor and an electric bicycle.

[0006] In order to achieve the above purpose, the technical solution adopted by the utility model is:

[0007] According to one aspect of the utility model, there is provided a mid-mounted motor, comprising an electric mechanism, a mid-shaft, an output shaft and a ratchet assembly;

[0008] The electric mechanism and the middle shaft are configured to selectively drive the output shaft;

[0009] The output shaft and the ratchet assembly are respectively sleeved on the central shaft, the axis of the output shaft, the axis of the ratchet assembly and the axis of the central shaft are configured to be coaxial, and along the radial direction of the central shaft, the ratchet assembly is confined between the output shaft and the central shaft;

[0010] The ratchet assembly includes a first ratchet, a second ratchet and an elastic component, the first ratchet has a first tooth portion, the second ratchet is provided with a second tooth portion, along the axial direction of the central axis, the first tooth portion and the second tooth portion have a first state of mutual engagement and a second state of mutual separation, and the elastic component is used to control the first tooth portion and the second tooth portion to transition from the second state to the first state.

[0011] Furthermore, the elastic component is specifically a first magnetic ring and a second magnetic ring;

[0012] The first magnetic ring and the second magnetic ring are respectively sleeved on the central shaft, wherein the first magnetic ring is arranged on the output shaft, and the second magnetic ring is arranged on the second ratchet;

[0013] A repulsive force is formed between the first magnetic ring and the second magnetic ring, and a gap is left between the first magnetic ring and the second magnetic ring.

[0014] Furthermore, there is a minimum state and a maximum state of the gap between the first magnetic ring and the second magnetic ring;

[0015] When the first tooth portion and the second tooth portion are in the first state, along the axis of the central axis, the width of the gap is a first width;

[0016] When the first tooth portion and the second tooth portion are in the second state, along the axis of the central axis, the width of the gap is a second width;

[0017] The first width is greater than the second width, and the second width is configured to be greater than or equal to zero.

[0018] Furthermore, a first mounting sleeve is provided on the central axis, and along the circumferential direction of the central axis, the first mounting sleeve and the central axis are configured to be fixedly connected;

[0019] The first mounting sleeve and the first ratchet are connected by a spline;

[0020] The output shaft and the second ratchet are connected by a spline, and the first magnetic ring is arranged on the second ratchet;

[0021] The output shaft is provided with a second mounting sleeve, which is sleeved on the central shaft. Along the circumferential direction of the central shaft, the second mounting sleeve and the output shaft are configured to be spline-connected, and the second magnetic ring is arranged on the second mounting sleeve.

[0022] Further, the first ratchet is provided with a first positioning portion in the shape of a sleeve, a first connecting portion in the shape of a sleeve, and a first annular portion;

[0023] The first positioning portion, the first connecting portion and the first annular portion are integrally formed. Along the axis direction of the central axis, the first connecting portion and the first positioning portion are respectively located at two ends of the first annular portion. Along the radial direction of the central axis, the diameter of the first annular portion is greater than the diameter of the first connecting portion, and the diameter of the first connecting portion is greater than the diameter of the first positioning portion. The end surface of the first annular portion facing the second ratchet is provided with the first tooth portion, and the inner circumferential surface of the first connecting portion is provided with a spline for connecting with the first mounting sleeve.

[0024] The first positioning portion and the central axis are configured to be clearance-fitted.

[0025] Furthermore, the second ratchet is provided with a second positioning portion and a second annular portion in a sleeve shape;

[0026] The second positioning portion and the second annular portion are integrally formed, and along the radial direction of the central axis, the diameter of the second positioning portion is larger than the diameter of the second annular portion, wherein a spline for connecting the output shaft is arranged on the outer circumferential surface of the second positioning portion, and the first magnetic ring is arranged on the end surface of the second annular portion facing the second mounting sleeve.

[0027] Furthermore, the second mounting sleeve is provided with a third positioning portion and a third annular portion in a sleeve shape;

[0028] The third positioning portion and the third circular ring portion are integrally formed, and along the radial direction of the central axis, the diameter of the third positioning portion is larger than the diameter of the third circular ring portion, wherein the second magnetic ring is fixedly arranged on the inner circumferential surface of the third positioning portion, and one surface of the second magnetic ring is in contact with the end surface of the third circular ring portion facing the second ratchet.

[0029] Furthermore, a one-way clutch is provided between the middle shaft and the output shaft.

[0030] Further, the electric mechanism includes a motor and a harmonic generator;

[0031] The motor comprises a housing, a stator and a rotor, wherein the stator and the rotor are respectively arranged in the housing, and the housing, the stator and the rotor are respectively sleeved on the central shaft;

[0032] The harmonic generator comprises a steel wheel, a flexible wheel and a wave generator, wherein the steel wheel, the flexible wheel and the wave generator are respectively sleeved on the central shaft, the rotor is coaxially connected to the wave generator, and the flexible wheel is connected to the output shaft via a one-way clutch.

[0033] According to one aspect of the utility model, an electric bicycle is provided, comprising the aforementioned mid-mounted motor.

[0034] The above technical solution has the following advantages or beneficial effects:

[0035] The utility model provides a central motor, a ratchet assembly located between the central shaft and the output shaft, and is used in conjunction with a one-way bearing located between the central shaft and the output shaft. When the central shaft transmits kinetic energy to the output shaft through the one-way clutch, the central shaft can also transmit kinetic energy to the output shaft through the ratchet assembly. The first ratchet and the second ratchet of the ratchet assembly adopt a first tooth portion and a second tooth portion to engage with or separate from each other. Therefore, when the first tooth portion and the second tooth portion are engaged with each other, since the first tooth portion and the second tooth portion form a surface-to-surface contact, the contact area between the two is relatively large. When the same pressure is applied to the first tooth portion and the second tooth portion, the pressure applied to the first tooth portion and the second tooth portion is relatively small, and the degree of tooth wear of the first tooth portion and the second tooth portion is relatively slower, thereby having higher reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 A schematic diagram of the structure of a central motor provided in Example 1 of the utility model;

[0037] Figure 2 A schematic diagram of the structure of a first ratchet provided in Example 1 of the utility model;

[0038] Figure 3 A schematic diagram of the structure of a second ratchet provided in Example 1 of the utility model;

[0039] Figure 4 A schematic diagram of the structure of the second installation sleeve provided in Example 1 of the utility model;

[0040] Figure 5 This is a schematic diagram of the structure of the output shaft provided in Example 1 of the utility model. DETAILED DESCRIPTION

[0041] Embodiment 1:

[0042] In this embodiment, in order to solve the technical problem of how to improve the reliability of the one-way transmission between the central shaft and the output shaft, this embodiment provides a mid-mounted motor.

[0043] For details, see Figure 1 The central motor of this embodiment includes an electric mechanism 1, a central shaft 2, an output shaft 3 and a ratchet assembly 4;

[0044] The electric mechanism 1 and the central shaft 2 are configured as an alternative drive output shaft 3;

[0045] The output shaft 3 and the ratchet assembly 4 are respectively sleeved on the middle shaft 2, and the axis center line of the output shaft 3, the axis center line of the ratchet assembly 4 and the axis center line of the middle shaft 2 are configured to be coaxial, and along the radial direction of the middle shaft 2, the ratchet assembly 4 is restricted between the output shaft 3 and the middle shaft 2;

[0046] The ratchet assembly 4 includes a first ratchet 411, a second ratchet 412 and an elastic component 413. The first ratchet 411 has a first tooth portion, and the second ratchet 412 is provided with a second tooth portion. Along the axial direction of the central axis 2, the first tooth portion and the second tooth portion have a first state of mutual engagement and a second state of mutual separation. The elastic component 413 is used to control the first tooth portion and the second tooth portion to transition from the second state to the first state.

[0047] The electric mechanism 1 and the central shaft 2 are configured as an alternative drive output shaft 3 (see Figure 3 Output shaft 3);

[0048] Specifically, when the electric mechanism 1 drives the output shaft 3, as the output shaft 3 rotates, the middle shaft 2 can remain relatively still. This is because the ratchet assembly 4 in this embodiment is provided between the middle shaft 2 and the output shaft 3, and a one-way clutch in the prior art is provided. The ratchet assembly 4 has a one-way transmission function, which is common knowledge known to those skilled in the art.

[0049] On the contrary, when the intermediate shaft 2 drives the output shaft 3, as the output shaft 3 rotates, the output end of the electric mechanism 1 can remain relatively still. This is because a one-way clutch in the prior art is provided between the electric mechanism 1 and the output shaft 3, and the one-way clutch can adopt a one-way bearing.

[0050] In this embodiment, when the electric mechanism 1 drives the output shaft 3 to rotate, the one-way clutch between the output shaft 3 and the electric mechanism 1 is in a locked state, so that the kinetic energy of the electric mechanism 1 can be transmitted to the output shaft 3, causing the output shaft 3 to rotate; as the output shaft 3 rotates, the output shaft 3 drives the second ratchet 412 to generate a rotation trend; at the same time, the one-way clutch between the middle shaft 2 and the output shaft 3 is in an unlocked state, so that the middle shaft 2 remains relatively stationary;

[0051] When the second ratchet 412 has a tendency to rotate, the second tooth portion of the second ratchet 412 pushes the first tooth portion of the first ratchet 411. Since the tooth surface where the first tooth portion contacts the second tooth portion is an inclined surface, and the tooth surface where the second tooth portion contacts the first tooth portion is an inclined surface, the second tooth portion applies a force to the first tooth portion while the first tooth portion applies a reaction force to the second tooth portion. With this reaction force, an axial force along the axis centerline direction of the central axis 2 is generated between the inclined surfaces of the first tooth portion and the inclined surfaces of the second tooth portion. With this axial force, the second ratchet 412 is pushed by the first ratchet 411 to form a movement along the center line direction of the central axis 2. At this time, the second ratchet 412 compresses the elastic component 413, so that the length of the elastic component 413 is reduced; in the process of the first ratchet 411 further pushing the second ratchet 412, until the first tooth portion and the second tooth portion are separated from each other, the elastic component 413 reaches the shortest state during the operation of the ratchet assembly 4; when the first tooth portion and the second tooth portion are separated from each other, the tooth peak of the first tooth portion passes over the tooth peak of the second tooth portion, so that the first ratchet 411 generates a circumferential rotation path;

[0052] Then, after the tooth peak of the first tooth portion passes over the tooth peak of the second tooth portion, the elastic force of the elastic component 413 drives the second ratchet 412, so that the second tooth portion of the second ratchet 412 is inserted into the first tooth portion of the first ratchet 411 again, until the tooth peak of the second tooth portion moves to the tooth valley of the first tooth portion, so that the tooth surface of the first tooth portion and the tooth surface of the second tooth portion form surface-to-surface contact again.

[0053] As the process of the electric mechanism 1 driving the output shaft 3 to rotate continues, the first ratchet 411 remains relatively stationary in the axial direction relative to the central axis 2, and forms a relatively stationary state relative to the radial direction of the central axis 2. At the same time, the second ratchet 412 maintains reciprocating motion along the axial direction relative to the central axis 2, and forms a relatively rotating state relative to the radial direction of the central axis 2, thereby forming a periodic spacing change between the first ratchet 411 and the second ratchet 412, thereby enabling the electric mechanism 1 to continuously drive the output shaft 3 to rotate.

[0054] In this embodiment, when the middle shaft 2 drives the output shaft 3 to rotate, the one-way clutch between the middle shaft 2 and the output shaft 3 is in a locking structure, so that the kinetic energy of the middle shaft 2 is transmitted to the output shaft 3. In other words, a first transmission structure is formed between the middle shaft 2, the one-way clutch and the output shaft 3; at the same time, the second ratchet 412 on the output shaft 3 rotates simultaneously with the output shaft 3, and the first ratchet 411 on the middle shaft 2 rotates simultaneously with the middle shaft 2, so that the first ratchet 411 and the second ratchet 412 form a synchronous rotation process, in which the second ratchet 412 cannot apply a force to the first ratchet 411, resulting in the first ratchet 411 being locked. The first ratchet 411 cannot apply a reaction force to the second ratchet 412, and the elastic component 413 cannot be compressed, resulting in the first ratchet 411 and the second ratchet 412 always remaining in a meshing state. As a result, the kinetic energy of the middle shaft 2 can be applied to the output shaft 3 through the ratchet assembly 4, thereby realizing a second transmission structure between the middle shaft 2, the ratchet assembly 4 and the output shaft 3 (the first transmission structure is formed by the one-way clutch between the middle shaft 2 and the output shaft 3 mentioned above); at the same time, the one-way clutch between the output shaft 3 and the electric mechanism 1 is changed to an unlocked state, thereby avoiding the phenomenon that the output end of the electric mechanism 1 rotates while the middle shaft 2 rotates.

[0055] It should be understood that the first transmission structure and the second transmission structure simultaneously generate a transmission effect from the central shaft 2 to the output shaft 3, and the first transmission structure also plays a role in keeping the ratchet assembly 4 in a meshing state.

[0056] In this embodiment, the ratchet assembly 4 located between the middle shaft 2 and the output shaft 3 is used in conjunction with the one-way bearing located between the middle shaft 2 and the output shaft 3. While the middle shaft 2 transmits kinetic energy to the output shaft 3 through the one-way clutch, the middle shaft 2 can also transmit kinetic energy to the output shaft 3 through the ratchet assembly 4. The first ratchet 411 and the second ratchet 412 of the ratchet assembly 4 adopt a first tooth portion and a second tooth portion to engage with or separate from each other. Therefore, when the first tooth portion and the second tooth portion are engaged with each other, since the first tooth portion and the second tooth portion form a surface-to-surface contact, the contact area between the two is relatively large. When the same pressure is applied to the first tooth portion and the second tooth portion, the pressure on the first tooth portion and the second tooth portion is relatively small, and the degree of tooth wear of the first tooth portion and the second tooth portion is relatively slower, thereby having higher reliability.

[0057] Correspondingly, point-like or line-like contact is formed between the needle roller of the one-way bearing in the prior art and the tooth tip of the one-way bearing, so that the contact area between the two is relatively small. When the same pressure is applied to the needle roller and the tooth tip, the pressure applied to the needle roller is relatively large, and the needle roller wears relatively faster, resulting in lower reliability.

[0058] Therefore, the central motor of this embodiment enhances the strength of the transmission structure between the central shaft 2 and the output shaft 3 through the ratchet assembly 4, thereby solving the technical problem of how to improve the reliability of the one-way transmission between the central shaft 2 and the output shaft 3.

[0059] In the following content, in order to facilitate the understanding of those skilled in the art, this embodiment provides a specific structure of a preferred mid-mounted motor, which includes the connection method between the electric mechanism 1 and the output shaft 3, as well as the positional relationship and connection relationship between the electric mechanism 1, the central shaft 2 and the output shaft 3, which are not mentioned here for the time being.

[0060] Further, in this embodiment, see Figure 1 , Figure 3 or Figure 4 , the elastic component 413 is specifically a first magnetic ring 421 and a second magnetic ring 422;

[0061] The first magnetic ring 421 and the second magnetic ring 422 are respectively sleeved on the central shaft 2, wherein the first magnetic ring 421 is arranged on the output shaft 3, and the second magnetic ring 422 is arranged on the second ratchet 412;

[0062] A repulsive force is formed between the first magnetic ring 421 and the second magnetic ring 422 , and a gap is left between the first magnetic ring 421 and the second magnetic ring 422 .

[0063] It should be understood that, in addition to being configured as the first magnetic ring 421 and the second magnetic ring 422 , in other embodiments, the elastic component 413 may also be configured as a coil spring.

[0064] In this embodiment, the repulsive force between the first magnetic ring 421 and the second magnetic ring 422 is equivalent to the elastic force of the spring; in other words, due to the repulsive force between the first magnetic ring 421 and the second magnetic ring 422, the second ratchet 412 can generate a movement tendency toward the direction of the first ratchet 411 under the action of the repulsive force, so that the second ratchet 412 and the first ratchet 411 can engage with each other.

[0065] The gap between the first magnetic ring 421 and the second magnetic ring 422 plays the following two roles:

[0066] Function 1: The gap between the first magnetic ring 421 and the second magnetic ring 422 is equivalent to the space between the two ends of the coil spring. When the first magnetic ring 421 and the second magnetic ring 422 are in a position close to each other, the second magnetic ring 422 is displaced toward the first magnetic ring 421. The length of the displacement is the axial length of the gap. The overall displacement space of the second magnetic ring 422 is the space occupied by the gap.

[0067] Function 2: The axial length of the gap between the second magnetic ring 422 and the first magnetic ring 421 is preferably configured to be greater than the axial length of the second ratchet 412. Specifically:

[0068] There is a minimum state and a maximum state of a gap between the first magnetic ring 421 and the second magnetic ring 422 ;

[0069] When the first tooth portion and the second tooth portion are in the first state, along the axis of the central axis 2, the width of the gap is a first width;

[0070] When the first tooth portion and the second tooth portion are in the second state, the width of the gap along the axis of the central axis 2 is the second width;

[0071] The first width is greater than the second width, and the second width is configured to be greater than or equal to zero.

[0072] Under the setting of the above-mentioned preferred scheme, even if the first ratchet 411 and the second ratchet 412 have been separated from each other, the gap between the first magnetic ring 421 and the second magnetic ring 422 still exists; in other words, since in the preferred scheme, the gap between the first magnetic ring 421 and the second magnetic ring 422 always exists, and thus no friction force can be generated between the first magnetic ring 421 and the second magnetic ring 422, the durability of the first magnetic ring 421 and the second magnetic ring 422 is improved, and the reliability of the ratchet assembly 4 is increased.

[0073] The above-mentioned elastic component 413 using a coil spring is used as a comparative example; the elastic component 413 composed of the first magnetic ring 421 and the second magnetic ring 422 in the above-mentioned preferred solution, relative to the coil spring in the comparative example, the first magnetic ring 421 and the second magnetic ring 422 cannot generate friction, and thus the reliability is higher than the coil spring in the comparative example.

[0074] For further information, see Figure 1 In the central motor of this embodiment, a first mounting sleeve 5 is disposed on the central axis 2, and along the circumferential direction of the central axis 2, the first mounting sleeve 5 and the central axis 2 are configured to be fixedly connected;

[0075] The first mounting sleeve 5 and the first ratchet wheel 411 are connected by a spline;

[0076] The output shaft 3 and the second ratchet 412 are connected by a spline, and the first magnetic ring 421 is arranged on the second ratchet 412;

[0077] The output shaft 3 is provided with a second mounting sleeve 6 , which is sleeved on the middle shaft 2 . Along the circumferential direction of the middle shaft 2 , the second mounting sleeve 6 and the output shaft 3 are configured as a spline connection, and the second magnetic ring 422 is arranged on the second mounting sleeve 6 .

[0078] Among them, the connection method between the first mounting sleeve 5 and the central axis 2 can be achieved by using a positioning pin in combination with a positioning groove respectively arranged on the first mounting sleeve 5 and the central axis 2, or it can be achieved by setting a spline on the first mounting sleeve 5 and the central axis 2 respectively. This is common knowledge known to technical personnel in this field.

[0079] Since the central axis 2 is fixedly connected to the first mounting sleeve 5, the central axis 2 and the first mounting sleeve 5 always maintain synchronous movement or stillness along the radial direction of the central axis 2. Correspondingly, since a spline connection is adopted between the first mounting sleeve 5 and the first ratchet 411, the first ratchet 411 always maintains synchronous movement or stillness relative to the central axis 2 along the radial direction of the central axis 2.

[0080] Since the output shaft 3 and the second ratchet 412 are splined together, the output shaft 3 and the second ratchet 412 always maintain synchronous movement or stillness along the radial direction of the central axis 2. Correspondingly, since the first magnetic ring 421 is arranged on the second ratchet 412, the first magnetic ring 421 maintains synchronous movement or stillness relative to the output shaft 3.

[0081] The connection method between the second mounting sleeve 6 and the output shaft 3 can adopt the aforementioned spline connection or the aforementioned locating pin and locating groove connection method, which is common knowledge known to technical personnel in this field; on this basis, along the radial direction of the central axis 2, the second mounting sleeve 6 and the output shaft 3 always maintain synchronous movement or stillness, and then, the second magnetic ring 422 arranged on the second mounting sleeve 6 maintains synchronous movement or stillness relative to the output shaft 3.

[0082] It should be understood that the first magnetic ring 421 and the second ratchet 412 can be fixed together by bonding, and the second magnetic ring 422 and the second mounting sleeve 6 can be fixed together by bonding.

[0083] It should be understood that a spline connection is used between the first mounting sleeve 5 and the first ratchet 411, which can improve the assembly efficiency of the first mounting sleeve 5 and the first ratchet 411, and a spline connection is used between the output shaft 3 and the second ratchet 412, which can improve the assembly efficiency between the output shaft 3 and the second ratchet 412, and a spline connection is used between the second mounting sleeve 6 and the output shaft 3, which can improve the assembly efficiency between the second mounting sleeve 6 and the output shaft 3.

[0084] For further information, see Figure 2 , in the middle motor of this embodiment, the first ratchet 411 is provided with a first positioning portion 431 in the form of a sleeve, a first connecting portion 432 in the form of a sleeve, and a first annular portion 433;

[0085] The first positioning portion 431, the first connecting portion 432 and the first annular portion 433 are integrally formed. Along the axis of the central axis 2, the first connecting portion 432 and the first positioning portion 431 are respectively located at two ends of the first annular portion 433. Along the radial direction of the central axis 2, the diameter of the first annular portion 433 is larger than the diameter of the first connecting portion 432, and the diameter of the first connecting portion 432 is larger than the diameter of the first positioning portion 431. The end surface of the first annular portion 433 facing the second ratchet 412 is provided with a first tooth portion, and the inner circumferential surface of the first connecting portion 432 is provided with a spline for connecting to the first mounting sleeve 5.

[0086] The first positioning portion 431 and the central axis 2 are configured to be clearance-fitted.

[0087] Among them, the first positioning portion 431 forms a clearance fit with the central axis 2. On the one hand, it is convenient to put the first ratchet 411 as a whole on the central axis 2, thereby improving the assembly efficiency of the two. On the other hand, the first positioning portion 431 and the central axis 2 can form radial positioning, reducing or avoiding the radial displacement or swing of the first ratchet 411 relative to the central axis 2, thereby reducing the friction between the first ratchet 411 and the central axis 2, and improving the reliability of the first ratchet 411 and the central axis 2.

[0088] The purpose of setting the first annular portion 433 is to provide a processing space for processing the first tooth portion, so that when machining the first tooth portion of the first ratchet 411, the turning tool of the lathe can reach the space occupied by the first annular portion 433 to perform cutting or grinding of the first tooth portion.

[0089] For further information, see Figure 3 , the central motor of this embodiment, the second ratchet 412 is provided with a second positioning portion 441 and a second annular portion 442 in a sleeve shape;

[0090] The second positioning portion 441 and the second annular portion 442 are integrally formed, and along the radial direction of the central axis 2, the diameter of the second positioning portion 441 is larger than the diameter of the second annular portion 442, wherein a spline for connecting the output shaft 3 is arranged on the outer circumferential surface of the second positioning portion 441, and a first magnetic ring 421 is arranged on the end surface of the second annular portion 442 facing the second mounting sleeve 6.

[0091] The function of the second positioning portion 441 is to form a clearance fit between the second ratchet wheel 412 and the output shaft 3, thereby preventing the second positioning portion 441 from radially displacing or swinging relative to the output shaft 3;

[0092] The function of the second annular portion 442 is the same as or similar to that of the first annular portion 433 , and will not be described in detail here.

[0093] The first magnetic ring 421 is disposed at the position of the second annular portion 442 , and the second tooth portion is disposed at the position of the second annular portion 442 , and the two are separated by the second annular portion 442 .

[0094] For further information, see Figure 4 In the central motor of this embodiment, the second mounting sleeve 6 is provided with a third positioning portion 611 and a third annular portion 612 in a sleeve shape;

[0095] The third positioning portion 611 and the third circular portion 612 are integrally formed, and along the radial direction of the central axis 2, the diameter of the third positioning portion 611 is larger than the diameter of the third circular portion 612, wherein the second magnetic ring 422 is fixedly arranged on the inner circumferential surface of the third positioning portion 611, and one surface of the second magnetic ring 422 is in contact with the end surface of the third circular portion 612 facing the second ratchet 412.

[0096] The function of the third positioning portion 611 is to form a clearance fit between the second mounting sleeve 6 and the output shaft 3, thereby preventing the second mounting sleeve 6 from radially displacing or swinging relative to the output shaft 3; in addition, the outer circumferential surface of the aforementioned second positioning portion 441 is not provided with a spline, while the outer circumferential surface of the third positioning portion 611 is provided with a spline;

[0097] The third annular portion 612 functions to isolate the second magnetic ring 422 from the output shaft 3 along the axial direction.

[0098] For further information, see Figure 1 , based on all the aforementioned solutions, the central motor of this embodiment, the electric mechanism 1 includes a motor and a harmonic generator;

[0099] The motor includes a housing 111, a stator 112 and a rotor 113. The stator 112 and the rotor 113 are respectively arranged in the housing 111, and the housing 111, the stator 112 and the rotor 113 are respectively sleeved on the central shaft 2.

[0100] The harmonic generator includes a steel wheel 115, a flexible wheel 116 and a wave generator 117. The steel wheel 115, the flexible wheel 116 and the wave generator 117 are respectively sleeved on the central shaft 2. The rotor 113 is coaxially connected to the wave generator 117. The flexible wheel 116 is connected to the output shaft 3 through a one-way clutch.

[0101] Among them, the motor is entirely sleeved on the central axis 2, which can reduce the overall volume of the central motor; the motor shaft 114 of the motor is coaxially connected with the wave generator 117 of the harmonic generator, and when the stator 112 drives the rotor 113 to rotate, the rotor 113 drives the motor shaft 114 to rotate, and the motor shaft 114 drives the wave generator 117 to rotate, so that the wave generator 117 drives the flexible wheel 116 to rotate relative to the steel wheel 115; correspondingly, the steel wheel 115 is configured to be fixed relative to the housing 111 of the motor, wherein the connection method of the existing technology can be adopted between the steel wheel 115 and the housing 111, including bolt connection or positioning pin connection.

[0102] The working principle of the harmonic generator is common knowledge known to those skilled in the art and will not be described in detail here.

[0103] The flexible wheel 116 of the harmonic generator is connected to the one-way clutch located between the electric mechanism 1 and the output shaft 3; specifically, a clutch sleeve is provided on the end surface of the flexible wheel 116, and the clutch sleeve and the flexible wheel 116 are connected by screws or positioning pins. The one-way clutch is provided between the output shaft 3 and the clutch sleeve, wherein the circumferential outer surface of the one-way clutch is in close contact with the inner surface of the clutch sleeve, and the circumferential inner surface of the one-way clutch is in close contact with the circumferential outer surface of the output shaft 3;

[0104] In order to prevent the one-way clutch from being separated from the clutch sleeve and the output shaft 3 along the axial direction, retaining springs can be provided at both axial ends of the one-way clutch, and correspondingly, two retaining grooves are provided at the position where the one-way clutch is installed on the output shaft 3, and the retaining springs are inserted into the retaining grooves to form axial positioning of the one-way clutch; alternatively, one set of retaining springs and retaining grooves can be replaced with a positioning protrusion, which can also form axial positioning of the one-way clutch.

[0105] It should be understood that, in addition to the foregoing, the central motor in this embodiment is provided with slots at both ends of the central axis 2, and a retaining spring is used to restrict the aforementioned electric mechanism 1, ratchet assembly 4, output shaft 3 and other components between the two slots of the two central axes 2, thereby forming a positioning relative to the axial direction of the central axis 2.

[0106] It should be understood that see Figure 1 A torque sensor 7 can also be arranged on the central axis 2, which can be specifically arranged at the position of the aforementioned first mounting sleeve 5; the working principle and function of the torque sensor 7 are the same as those of the torque sensor in the prior art, and will not be repeated here.

[0107] It should be understood that outer protective shells can be provided at both ends of the middle shaft 2 along the axial direction of the middle shaft 2, so as to confine the components including the motor within the contour of the outer protective shell, wherein one end of the output shaft 3 extends to the outside of the outer protective shell, and the two ends of the middle shaft 2 extend to the outside of the outer protective shell.

[0108] Embodiment 2:

[0109] In this embodiment, an electric bicycle is provided, comprising the mid-mounted motor as in the aforementioned embodiment 1.

[0110] The central motor in this embodiment has the same function and structure as the central motor in the aforementioned embodiment 1, and the rest will not be described in detail.

[0111] The above description is only a preferred embodiment of the present invention, and does not limit the patent scope of the present invention. Any equivalent structural transformation made using the contents of the specification and drawings of the present invention, or directly or indirectly applied in other related technical fields, is also included in the patent protection scope of the present invention.

Claims

1. Mid-mounted motor, characterized in that: It includes an electric mechanism, a middle shaft, an output shaft and a ratchet assembly; The electric mechanism and the middle shaft are configured to selectively drive the output shaft; The output shaft and the ratchet assembly are respectively sleeved on the central shaft, the axis of the output shaft, the axis of the ratchet assembly and the axis of the central shaft are configured to be coaxial, and along the radial direction of the central shaft, the ratchet assembly is confined between the output shaft and the central shaft; The ratchet assembly includes a first ratchet, a second ratchet and an elastic component, the first ratchet has a first tooth portion, the second ratchet is provided with a second tooth portion, along the axial direction of the central axis, the first tooth portion and the second tooth portion have a first state of mutual engagement and a second state of mutual separation, and the elastic component is used to control the first tooth portion and the second tooth portion to transition from the second state to the first state.

2. The mid-mounted motor according to claim 1, characterized in that: The elastic component is specifically a first magnetic ring and a second magnetic ring; The first magnetic ring and the second magnetic ring are respectively sleeved on the central shaft, wherein the first magnetic ring is arranged on the output shaft, and the second magnetic ring is arranged on the second ratchet; A repulsive force is formed between the first magnetic ring and the second magnetic ring, and a gap is left between the first magnetic ring and the second magnetic ring.

3. The mid-mounted motor according to claim 2, characterized in that: There is a minimum state and a maximum state of the gap between the first magnetic ring and the second magnetic ring; When the first tooth portion and the second tooth portion are in the first state, along the axis of the central axis, the width of the gap is a first width; When the first tooth portion and the second tooth portion are in the second state, along the axis of the central axis, the width of the gap is a second width; The first width is greater than the second width, and the second width is configured to be greater than or equal to zero.

4. The mid-mounted motor according to claim 2, characterized in that: A first mounting sleeve is disposed on the central axis, and along the circumferential direction of the central axis, the first mounting sleeve is configured to be fixedly connected to the central axis; The first mounting sleeve and the first ratchet are connected by a spline; The output shaft and the second ratchet are connected by a spline, and the first magnetic ring is arranged on the second ratchet; The output shaft is provided with a second mounting sleeve, which is sleeved on the central shaft. Along the circumferential direction of the central shaft, the second mounting sleeve and the output shaft are configured to be spline-connected, and the second magnetic ring is arranged on the second mounting sleeve.

5. The mid-mounted motor according to claim 4, characterized in that: The first ratchet is provided with a first positioning portion in the shape of a sleeve, a first connecting portion in the shape of a sleeve, and a first annular portion; The first positioning portion, the first connecting portion and the first annular portion are integrally formed. Along the axis direction of the central axis, the first connecting portion and the first positioning portion are respectively located at two ends of the first annular portion. Along the radial direction of the central axis, the diameter of the first annular portion is greater than the diameter of the first connecting portion, and the diameter of the first connecting portion is greater than the diameter of the first positioning portion. The end surface of the first annular portion facing the second ratchet is provided with the first tooth portion, and the inner circumferential surface of the first connecting portion is provided with a spline for connecting with the first mounting sleeve. The first positioning portion and the central axis are configured to be clearance-fitted.

6. The mid-mounted motor according to claim 4, characterized in that: The second ratchet is provided with a second positioning portion and a second annular portion in a sleeve shape; The second positioning portion and the second annular portion are integrally formed, and along the radial direction of the central axis, the diameter of the second positioning portion is larger than the diameter of the second annular portion, wherein a spline for connecting the output shaft is arranged on the outer circumferential surface of the second positioning portion, and the first magnetic ring is arranged on the end surface of the second annular portion facing the second mounting sleeve.

7. The mid-mounted motor according to claim 4, characterized in that: The second mounting sleeve is provided with a third positioning portion and a third annular portion in a sleeve shape; The third positioning portion and the third circular ring portion are integrally formed, and along the radial direction of the central axis, the diameter of the third positioning portion is larger than the diameter of the third circular ring portion, wherein the second magnetic ring is fixedly arranged on the inner circumferential surface of the third positioning portion, and one surface of the second magnetic ring is in contact with the end surface of the third circular ring portion facing the second ratchet.

8. The mid-mounted motor according to any one of claims 1 to 7, characterized in that: A one-way clutch is arranged between the middle shaft and the output shaft.

9. The mid-mounted motor according to claim 1, characterized in that: The electric mechanism includes a motor and a harmonic generator; The motor comprises a housing, a stator and a rotor, wherein the stator and the rotor are respectively arranged in the housing, and the housing, the stator and the rotor are respectively sleeved on the central shaft; The harmonic generator comprises a steel wheel, a flexible wheel and a wave generator, wherein the steel wheel, the flexible wheel and the wave generator are respectively sleeved on the central shaft, the rotor is coaxially connected to the wave generator, and the flexible wheel is connected to the output shaft via a one-way clutch.

10. An electric bicycle, characterized in that: Including the mid-mounted motor as described in any one of claims 1 to 9.

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