CN115817699A - Wheel hub motor drive assembly and electric moped - Google Patents

Abstract

The invention relates to a hub motor drive assembly and an electric moped. The hub motor driving assembly includes a hub shaft, a driving motor, a speed reducer and a housing, the driving motor and the speed reducer being accommodated in the housing adjacently in an axial direction of the hub shaft, the speed reducer including a wave generator, a flexspline, a first rigid spline fixed to the hub shaft and a second rigid spline connected between the flexspline and the housing to transmit a driving torque from the flexspline to the housing, the flexspline and the wave generator being disposed inside the first rigid spline and the second rigid spline in a radial direction of the hub shaft and being disposed between the first rigid spline and the second rigid spline in the axial direction of the hub shaft. The hub motor driving assembly has the advantages of simple and compact structure, large reduction ratio and greatly improved reliability.

Description

Wheel hub motor drive assembly and electric moped

Technical Field

The invention relates to the field of electric moped. In particular, the invention relates to an in-wheel motor driving assembly and an electric moped comprising the in-wheel motor driving assembly.

Background

New energy sources have now become a rather prospective field in the field of travel, for example, electric power-assisted vehicles, which are distinguished from conventional motorcycles, employ hybrid power combining electric drive and manual pedaling. Among the most used electric drive technologies, the in-wheel motor technology (also called in-wheel motor technology) is used. The biggest characteristic of the technology is that a power device and a transmission device are assembled in a hub of a wheel, so that the mechanical structure of the electric vehicle is simplified.

At present, a wheel hub motor driving assembly has two schemes, wherein the first scheme adopts a direct-drive mode without a speed reducer, namely, a motor directly drives a wheel; the second solution is to use a reducer driving method, i.e. the torque of the driving motor is transmitted to the wheels after being increased by the reducer. For the first direct-drive mode, if a large torque output is required, the motor is generally required to have a sufficiently large volume, which is unacceptable in the market in the field of electric power-assisted vehicles requiring lightness, thinness, shortness and smallness, so that the motor is hardly realized as the mainstream in the market. For the second driving mode adopting the speed reducer, because the speed reducer mostly adopts a planetary speed reducing mechanism and is limited by space and structure, the speed reducing ratio is about 4-12, the output torque is smaller, and the application is limited, in the field of electric moped, the traditional hub motor adopting the planetary speed reducing mechanism is replaced by a middle motor with larger speed reducing ratio, larger output torque and higher cost.

Disclosure of Invention

Therefore, the invention aims to provide a motor driving system equipped with a novel speed reducer, which can overcome the defects of small reduction ratio, small output torque and the like of the traditional hub motor, and has smaller volume and lighter weight while having larger reduction ratio (more than or equal to 50) and output torque than a middle motor.

According to one aspect of the present invention, there is provided an in-wheel motor drive assembly comprising; a hub shaft, a driving motor, a speed reducer, and a housing, the driving motor and the speed reducer being accommodated in the housing adjacently in an axial direction of the hub shaft and being torque-proof connected to each other, wherein the speed reducer includes a wave generator, a flexspline, a first rigid spline fixed to the hub shaft, and a second rigid spline connected between the flexspline and the housing to transmit a driving torque from the flexspline to the housing, the flexspline and the wave generator being disposed inside the first and second rigid splines in a radial direction of the hub shaft and being arranged between the first and second rigid splines in the axial direction of the hub shaft.

According to an embodiment of the present invention, the flexible gear is sleeved outside the wave generator in a radial direction of the hub shaft and is supported by the wave generator, and opposite ends of the wave generator in an axial direction of the hub shaft abut against the first rigid gear and the second rigid gear, respectively.

According to an embodiment of the present invention, the first rigid wheel has a mounting portion extending in a radial direction of the hub axle and a first connecting portion extending from the mounting portion in an axial direction of the hub axle, a first groove for mounting the flexspline and the wave generator is provided on a side of the mounting portion facing the second rigid wheel, and the first connecting portion is engaged with the flexspline.

According to an embodiment of the present invention, the second rigid wheel has a body portion extending in a radial direction of the hub axle, and a second connecting portion and a third connecting portion extending from the body portion in sequence in an axial direction of the hub axle, a second groove for mounting the flexible gear and the wave generator is provided on a side of the body portion facing the first rigid wheel, the second connecting portion is engaged with the flexible gear, and the third connecting portion is engaged with the housing.

According to an embodiment of the present invention, the in-wheel motor drive assembly further comprises a stop member fixed to the second rigid wheel and abutting against the first rigid wheel to limit relative axial displacement between the first rigid wheel and the second rigid wheel.

According to an embodiment of the invention, the drive motor comprises a stator, a rotor and an output shaft connected torque-proof to the rotor, the first rigid wheel, the second rigid wheel and the output shaft together defining a closed reducer chamber.

According to an embodiment of the present invention, a first seal is provided between the first rigid wheel and the second rigid wheel, a second seal is provided between the first rigid wheel and the output shaft, and a third seal is provided between the second rigid wheel and the output shaft.

According to an embodiment of the present invention, the in-wheel motor driving assembly further includes a one-way clutch disposed between the output shaft and the wave generator to cut off or achieve a torque-resistant connection between the driving motor and the speed reducer, the one-way clutch being provided with a needle roller bearing at a radially inner side and/or an outer side thereof.

According to an embodiment of the invention, the rotor and the hub axle together define a closed motor cavity, the motor cavity and the retarder cavity each being fluidly sealed, the rotor being supported on the housing via a third bearing, the third bearing being a sealed bearing.

According to an embodiment of the present invention, the in-wheel motor drive assembly further includes a grease injection mechanism having a passage extending through the housing and the second rigid wheel for supplying grease to the speed reducer.

According to another aspect of the invention, there is also provided an electric bicycle comprising the hub driving assembly according to any of the above embodiments.

Therefore, according to the in-wheel motor driving assembly provided by the invention, by means of the configuration of the two rigid wheels, the axial positioning and the radial positioning of the flexible wheel can be realized while the driving torque of the flexible wheel is transmitted to the shell, so that the occupied space of the speed reducer can be reduced, the structure of the in-wheel motor driving assembly is simpler and more compact, and the manufacturing cost can be reduced. In addition, according to the in-wheel motor driving assembly of the present invention, by providing the needle roller bearing in the one-way clutch provided between the output shaft of the driving motor and the wave generator of the speed reducer, the radial force interference between the driving motor and the speed reducer can be reduced, so that the coaxiality of the driving motor and the speed reducer can be improved, and the transmission efficiency and the operational reliability of the speed reducer can be improved. Furthermore, according to the in-wheel motor driving assembly of the present invention, the two rigid wheels and the output shaft of the rotor form a closed reducer cavity, so that the reducer can be lubricated more efficiently, the operational reliability of the reducer can be improved, and the service life of the reducer can be prolonged.

Drawings

Features, advantages and technical effects of exemplary embodiments of the present invention will be described below by referring to the accompanying drawings.

FIG. 1 shows a schematic cross-sectional view of an in-wheel motor drive assembly according to an embodiment of the present invention.

FIG. 2 illustrates an enlarged cross-sectional schematic view of a retarder according to an embodiment of the present invention.

FIG. 3 shows a cross-sectional schematic view of a one-way clutch according to an embodiment of the present invention.

The drawings are not necessarily drawn to scale.

Detailed Description

The embodiments of the present invention will be described in further detail with reference to the drawings and examples. The following detailed description of the embodiments and the accompanying drawings are provided to illustrate the principles of the invention and are not intended to limit the scope of the invention, i.e., the invention is not limited to the described embodiments.

In the description of the present invention, it is to be noted that, unless otherwise specified, "a plurality" means two or more; the terms "inner", "outer", and the like, indicate an orientation or positional relationship merely to facilitate the description of the invention and to simplify the description, and do not indicate or imply that the referenced device or element must have a particular orientation, be constructed and operated in a particular orientation, and thus should not be construed as limiting the invention. Furthermore, the terms "first," "second," "third," and the like are used for descriptive purposes only and are not to be construed as indicating or implying relative importance. It will be readily understood that the term "torque-resistant connection" means that torque can be transmitted between two components, and that the manner in which the torque-resistant connection is achieved may include interference fits, bolted connections, and the like.

The following description is given with reference to the orientation words as shown in the drawings, and is not intended to limit the specific structure of the present invention. In the description of the present invention, it should also be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; may be directly connected or indirectly connected through an intermediate. The specific meaning of the above terms in the present invention can be understood as appropriate to those of ordinary skill in the art.

According to an embodiment of the invention, the in-wheel motor drive assembly is adapted to be mounted in a wheel of a motor vehicle for directly driving the wheel. Here, the motor vehicle may refer to any vehicle such as a bicycle, an electric motorcycle, etc. which needs to be additionally provided with a driving motor to provide power, and the present invention will be described by taking an electric bicycle as an example.

For a better understanding of the present invention, an in-wheel motor drive assembly 100 according to an embodiment of the present invention is described below with reference to fig. 1 to 3. FIG. 1 shows a schematic cross-sectional view of an in-wheel motor drive assembly 100 according to an embodiment of the present invention. As shown in fig. 1, the in-wheel motor drive assembly 100 is installed between a rear fork 1 and a rear fork 11 of a rear wheel of an electric power-assisted vehicle, and is disposed adjacent to a small sprocket 2.

The in-wheel motor drive assembly 100 includes a hub axle 10, a housing 6 and a cover 12. The hub axle 10 is disposed between the rear fork 1 and the rear fork 11 of the rear wheel. The housing 6 is supported on the hub axle 10 via the first bearing 3. The housing 6 is substantially cylindrical and has one side opened in the axial direction of the hub axle 10. The cover 12 is supported on the hub shaft 10 via the second bearing 9. The cover 12 covers the opening of the housing 6 and forms a working chamber a together with the housing 6. The housing 6 and the cover 12 are connected via bolts, for example, and together serve as a hub of a wheel.

With continued reference to FIG. 1, an in-wheel motor drive assembly 100 according to an embodiment of the present invention includes a drive motor 30 and a reducer 40 housed in a working chamber A. The drive motor 30 and the speed reducer 40 are accommodated in the working chamber a, are arranged adjacently in the axial direction of the hub axle 10, and are torque-proof connected to each other. Thus, the driving torque generated by the driving motor 30 can be amplified by the reducer 40 and then input to the housing 6 (i.e., the hub of the wheel), so that the wheel can be driven to rotate.

The driving motor 30 can be used to generate a driving torque, and includes a stator 7 coaxially fitted on the hub axle 10, a magnet 8, a rotor 5 and an output shaft 20. The stator 7 is fixed to the hub axle 10, the magnet 8 is disposed between the stator 7 and the rotor 5 and fixedly mounted to the rotor 5, the rotor 5 is rotatably supported on the hub axle 10, and the output shaft 20 is sleeved on the hub axle 10 and torque-proof connected to the rotor 5. Thus, the rotor 5 and the hub axle 10 together define a motor cavity A1. Illustratively, the rotor 5 is supported on the hub axle 10 via two third bearings 4, 13, wherein the two third bearings 4, 13 are sealed bearings and are disposed on both sides of the stator 7 in the axial direction of the hub axle 10, respectively. Thus, the motor cavity A1 is formed as a closed chamber. In addition, the drive motor 30 shown in fig. 2 is an inner rotor 5 motor, but according to other embodiments, the drive motor 30 may also be an outer rotor 5 motor.

As shown in fig. 2, the reducer 40 may be a harmonic reducer, and includes a wave generator 17, a flexspline 16, a first rigid spline 22, and a second rigid spline 15, which are coaxially nested. The wave generator 17 is mounted on the output shaft 20 of the drive motor 30 and is connected to the output shaft 20 of the drive motor 30 in a torque-proof manner, so that the wave generator 17 can be used as an input for the reduction gear 40. The flexspline 16 is fitted around the outside of the wave generator 17 in the radial direction of the hub axle 10 and supported by the wave generator 17. The flexspline 16 is made of a flexible material and is therefore deformable in response to rotation of the wave generator 17. First rigid wheel 22 and second rigid wheel 15 are each made of a rigid material. One of the first and second rigid wheels 22, 15 (e.g., the first rigid wheel 22) may be fixed to the hub axle 10 and may be connected to the flexspline 16. The first rigid gear 22 and the flexible gear 16 may be connected via a gear or spline engagement, illustratively, the first rigid gear 22 is provided with internal gear teeth and the flexible gear 16 is provided with external gear teeth, so that the flexible gear 16 may rotate relative to the first rigid gear 22 via the engagement of the internal and external gear teeth when the first rigid gear 22 is fixed to the hub axle 10. The other of the first and second rigid wheels 22, 15 (e.g., the second rigid wheel 15) may be disposed between the flexspline 16 and the housing 6 to transmit the driving torque from the flexspline 16 to the housing 6 (i.e., the hub of the wheel), thereby serving as an output of the reducer 40. The second rigid gear 15 and the flexible gear 16 may be engaged via gears, for example, the second rigid gear 15 is provided with inner gear teeth and the flexible gear 16 is provided with outer gear teeth, whereby the driving torque may be transmitted from the flexible gear 16 to the second rigid gear 15 via the engagement of the inner and outer gear teeth. The number of inner wheels of the second rigid wheel 15 may be equal to the number of inner wheels of the first rigid wheel 22 and greater than the number of outer wheels of the flexible wheel 16, for example greater than one or two teeth, although the invention is not limited thereto. The second rigid gear 15 and the housing 6 may be connected via a gear or spline engagement, for example, the second rigid gear 15 is further provided with external gear teeth and the flexible gear 16 is provided with internal gear teeth, whereby the drive torque may be transmitted from the second rigid gear 15 to the housing 6 via the engagement of the internal and external gear teeth.

When the output torque of the driving motor 30 is transmitted from the output shaft 20 to the wave generator 17 of the reducer 40 to rotate the wave generator 17, the rotation of the wave generator 17 deforms the flexible gear 16, for example, the cross section of the flexible gear 16 is changed from the original circular shape to the elliptical shape, so that the external gear teeth near both ends of the major axis thereof are completely engaged with the internal gear teeth of the second rigid gear 15, the external gear teeth near both ends of the minor axis thereof are completely disengaged from the internal gear teeth of the second rigid gear 15, and the external gear teeth of the other sections in the circumferential direction of the flexible gear 16 are in a transition state of engagement and disengagement with the internal gear teeth of the second rigid gear 15. Thus, the respective gear teeth of the flexspline 16 and the second ring spline 15 constantly change their respective operating states during meshing, meshing and disengaging, so-called staggered tooth movement is generated, and the speed reduction and torque increase effects of power transmission are achieved. The amplified drive torque may then be transmitted to the housing 6 via the second rigid wheel 15.

Therefore, according to the in-wheel motor driving assembly 100 of the embodiment of the present invention, the output torque is adjusted by the speed reducer 40, and the speed reduction and torque increase of the power transmission are realized by integrating the speed reducer 40 and the driving motor 30 in one working chamber a, so that a larger speed reduction ratio can be obtained in a limited installation space, thereby avoiding the use of multi-step gear transmission, making the overall structure of the in-wheel motor driving assembly 100 more compact, lighter in weight, higher in transmission efficiency, and capable of obtaining higher output torque.

With continued reference to FIG. 2, the flexspline 16 is disposed outboard of the wave generator 17 and inboard of the first and second rigid gears 22, 15 in the radial direction of the hub axle 10; meanwhile, the flexspline 16 is disposed between the first and second rigid gears 22 and 15 in the axial direction of the hub axle 10. Thereby, the first and second rigid gears 22 and 15 can achieve the positioning of the flexspline 16 in both the axial and radial directions. This arrangement can reduce the occupied space of the speed reducer 40, make the structure of the in-wheel motor drive assembly 100 simpler and more compact, and can reduce the manufacturing cost.

As described above, since the first rigid wheel 22 is fixed to the hub axle 10, the first rigid wheel 22 does not transmit the amplified driving torque, whereas since the second rigid wheel 15 is disposed to transmit the amplified driving torque to the housing 6, the first rigid wheel 22 is fixed differently, but the second rigid wheel 15 needs to rotate about the hub axle 10. At this time, in order to avoid interference therebetween, the first and second rigid wheels 22 and 15 are arranged to be provided at intervals in both the axial direction and the radial direction of the hub axle 10. To ensure the relative axial spacing between first connection portion 222 of first rigid wheel 22 and second connection portion 152 of second rigid wheel 15, in-wheel motor drive assembly 100 further includes a stop member 23, and stop member 23 is fixed to second rigid wheel 15 and abuts against first rigid wheel 22. The stop 23 may be a C-shaped snap ring.

The first rigid wheel 22 is generally L-shaped in configuration and has a mounting portion 221 extending in a radial direction of the hub axle 10 and a first connecting portion 222 extending from the mounting portion 221 in an axial direction of the hub axle 10 toward the second rigid wheel 15. The side of the mounting portion 221 facing the second rigid wheel 15 is provided with a first groove. The first coupling portion 222 is provided with internal gear teeth on an inner side in the radial direction of the hub axle 10, which can be engaged with a portion of the external gear teeth on the flexible gear 16.

Second rigid wheel 15 has a body portion 151 extending in a radial direction of hub axle 10, and a second coupling portion 152 and a third coupling portion 153 extending in order from body portion 151 in an axial direction of hub axle 10. The side of the body portion 151 facing the first rigid wheel 22 is provided with a second groove. The second grooves and the first grooves are disposed corresponding to each other and are configured to receive the wave generator 17 and opposite ends of the flexspline 16 in the axial direction of the hub axle 10. Thus, the mounting portion 221 of the first rigid gear 22 and the body portion 151 of the second rigid gear 15 can respectively abut against opposite ends of the wave generator 17 in the axial direction of the hub axle 10, and the wave generator 17 and the flexspline 16 can be axially positioned by matching the design that the first rigid gear 22 is fixed to the hub axle 10. The second connecting portion 152 extends from the body portion 151 toward the first rigid wheel 22 in the axial direction of the hub axle 10 and extends to a distance from the first connecting portion 222 of the first rigid wheel 22. The second coupling portion 152 is provided with internal gear teeth on the inner side in the radial direction of the hub axle 10, which can be engaged with a portion of the external gear teeth on the flexible gear 16. Thereby, the first connecting portion 222 of the first rigid gear 22 and the second connecting portion 152 of the second rigid gear 15 collectively wrap the radially outer side of the flexspline 16, thereby achieving radial positioning of the wave generator 17 and the flexspline 16. The third connecting portion 153 extends from the first connecting portion 222 in the axial direction of the hub axle 10 and extends until abutting against the cover 12. Thus, the first rigid wheel 22 is disposed inside the third connecting portion 153 of the second rigid wheel 15 in the radial direction of the hub axle 10, and this arrangement makes the structure of the speed reducer more compact. Further, the third coupling portion 153 is provided with external gear teeth on the outer side in the radial direction of the hub axle 10, which can be engaged with the internal gear teeth formed on the housing 6. Also, the third connecting portion 153 is spaced apart from the first connecting portion 222 of the first rigid wheel 22 in the radial direction of the hub axle 10.

With continued reference to fig. 2, the in-wheel motor drive assembly 100 according to an embodiment of the present invention further includes a one-way clutch 19 provided between the output shaft 20 and the wave generator 17 to cut off or enable a torque-resistant connection between the drive motor 30 and the reducer 40. When the speed of the wave generator 17 is lower than that of the output shaft 20, the one-way clutch 19 is closed, whereby the output shaft 20 can transmit the driving torque to the wave generator 17, then to the second rigid gear 15 through the flexible gear and finally to the housing 6, and when the speed of the wave generator 17 is higher than that of the output shaft 20, the one-way clutch 19 is opened, whereby the wave generator 17 does not transmit the torque to the output shaft 20, thus preventing the wave generator 17 from rotating back to the output shaft 20, thereby improving safety performance and reducing energy loss. Thus, when the one-way clutch 19 is closed, the one-way clutch 19 will effect a torque-resistant connection between the drive motor 30 and the reduction gear 40, and when the one-way clutch 19 is open, the one-way clutch 19 will break the torque-resistant connection between the drive motor 30 and the reduction gear 40.

Further, a needle bearing may be provided on the inner side and/or the outer side of the one-way clutch 19 in the radial direction of the hub axle 10. Fig. 3 shows only that needle bearings 191 and 192 are provided on the radially inner side of the one-way clutch 19, which are provided at both axial ends of the one-way clutch 19, respectively. For example, it is shown that the number of the needle roller bearings may be one pair, but the present invention is not limited thereto, and the number of the needle roller bearings may be two pairs or more. By means of the needle bearings 191 and 192, it is possible to reduce the interference of the radial force between the driving motor 30 and the reducer 40, thereby further improving the coaxiality between the output shaft 20 and the wave generator 17, and thus improving the transmission efficiency and operational reliability of the reducer 40.

With continued reference to fig. 1 and 2, a reducer chamber A2 is also formed within the working chamber a of the in-wheel motor drive assembly 100 and is defined by the first rigid gear 22, the second rigid gear 15, and the output shaft 20. The reducer cavity A2 and the motor cavity A1 are independent and closed from each other. That is, the retarder cavity A2 and the motor cavity A1 do not have fluid communication with each other. In order to isolate the retarder cavity A2 from the external environment, prevent external dust, dirty water, etc. from entering the retarder cavity A2, and ensure a clean lubrication and cooling fluid environment of the retarder cavity A2, the in-wheel motor drive assembly 100 further includes three sealing members, i.e., a first sealing member 24 disposed between the first rigid wheel 22 and the second rigid wheel 15, a second sealing member 21 disposed between the first rigid wheel 22 and the output shaft 20, and a third sealing member 18 disposed between the second rigid wheel 15 and the output shaft 20. The first seal 24, the second seal 21 and the third seal 18 may be made of plastic such as polytetrafluoroethylene.

First seal 24 may be disposed between first connection portion 222 of first rigid wheel 22 and third connection portion 153 of second rigid wheel 15 in a radial direction of hub axle 10. Therefore, the first seal 24 not only has a sealing effect between the first rigid ring gear 22 and the second rigid ring gear 15, but also can secure a radial gap between the first rigid ring gear 22 and the second rigid ring gear 15. Furthermore, the first seal 24 may be disposed against the stopper 23, thereby being able to be restricted in its axial displacement by the stopper 23. The second sealing member 21 is disposed on the output shaft 20 and accommodated in a step portion formed on the output shaft 20, and along the axial direction of the hub axle 10, one end of the second sealing member 21 abuts against the body portion 151 of the first rigid wheel 22, and the other end abuts against the output shaft 20. Thus, the second seal 21 may be disposed between the body portion 151 of the first rigid gear 22 and the output shaft 20 in the axial direction of the hub axle 10 to have an effect of radially sealing the reducer cavity A2. The third seal 18 may be disposed between the body portion 151 of the second rigid gear 15 and the output shaft 20 in the radial direction of the hub axle 10 to serve as an effect of axially sealing the reducer cavity A2.

The retarder cavity A2 can be sealed off from the environment motor cavity A1 by means of a first seal 24, a second seal 21 and a third seal 18. Of course, the sealing of the reducer cavity A2 of the in-wheel motor driving assembly 100 according to the present invention is not limited to the above-mentioned manner, and the object of the present invention can be achieved as long as the reducer cavity A2 can be sealed from the external environment or other cavities while being in fluid communication with the motor cavity A1.

Thus, according to the in-wheel motor drive assembly 100 of the embodiment of the present invention, by forming the closed reduction gear chamber A2, leakage of the lubricating fluid in the reduction gear chamber A2 can be reduced, thereby enabling lubrication of the reduction gear 40 with higher efficiency, further improving the operational reliability of the reduction gear 40, and improving the service life of the reduction gear 40.

In addition, in order to enable easier lubrication of the reduction gear 40, the in-wheel motor drive assembly 100 according to the embodiment of the present invention further includes a grease injection structure 14 configured to supply lubricating oil to the reduction gear 40 through the housing 6 and the second rigid gear 15. Preferably, the grease injection structure 14 is disposed in an inclined direction to both the axial direction and the radial direction of the hub axle 10, and the outlet of the grease injection structure 14 is located at the second connection of the second cylinder.

Therefore, according to the in-wheel motor drive assembly 100 of the present invention, by virtue of the configuration of the two rigid pulleys 22 and 15, the axial positioning and the radial positioning of the flexspline 16 can be achieved while transmitting the driving torque to the housing 6, whereby the occupied space of the reducer 40 can be reduced, the structure of the in-wheel motor drive assembly 100 can be made simpler and more compact, and the manufacturing cost can be reduced. In addition, according to the in-wheel motor driving assembly 100 of the present invention, by providing the needle bearings 191 and 192 in the one-way clutch 19 provided between the output shaft 20 of the driving motor 30 and the wave generator 17 of the speed reducer 40, it is possible to reduce the interference of the radial force between the driving motor 30 and the speed reducer 40, so that the coaxiality of the driving motor 30 and the speed reducer 40 can be ensured, thereby improving the transmission efficiency and the operational reliability of the speed reducer 40. Furthermore, according to the in-wheel motor driving assembly 100 of the present invention, by forming a closed reducer chamber A2 by the two rigid wheels 22 and 15 and the output shaft 20 of the rotor 5, the reducer 40 can be lubricated more efficiently, so that the operational reliability of the reducer 40 can be improved, and the service life of the reducer 40 can be increased.

While the invention has been described with reference to a preferred embodiment, various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention, and particularly, features shown in the various embodiments may be combined in any suitable manner without departing from the scope of the invention. It is intended that the invention not be limited to the particular embodiments disclosed, but that the invention will include all embodiments falling within the scope of the appended claims.

Claims (11)

1. An in-wheel motor drive assembly (100) comprising; a hub axle (10), a drive motor (30), a speed reducer (40) and a housing (6), the drive motor (30) and the speed reducer (40) being accommodated in the housing (6) adjacently in an axial direction of the hub axle (10) and being torque-proof connected to each other,

the speed reducer (40) comprises a wave generator (17), a flexible gear (16), a first rigid gear (22) and a second rigid gear (15), wherein the first rigid gear (22) is fixed on the hub shaft (10), the second rigid gear (15) is connected between the flexible gear (16) and the shell (6) so as to transmit the driving torque from the flexible gear (16) to the shell (6), the flexible gear (16) and the wave generator (17) are arranged on the inner sides of the first rigid gear (22) and the second rigid gear (15) along the radial direction of the hub shaft (10), and are arranged between the first rigid gear (22) and the second rigid gear (15) along the axial direction of the hub shaft (10).

2. The in-wheel motor drive assembly (100) according to claim 1, wherein the flexible gear (16) is sleeved outside the wave generator (17) in a radial direction of the hub axle (10) and supported by the wave generator (17), and opposite ends of the wave generator (17) in an axial direction of the hub axle (10) abut against the first rigid gear (22) and the second rigid gear (15), respectively.

3. The in-wheel motor drive assembly (100) of claim 1, wherein the first rigid wheel (22) has a mounting portion (221) extending in a radial direction of the hub axle (10) and a first connecting portion (222) extending from the mounting portion (221) in an axial direction of the hub axle (10), a side of the mounting portion (221) facing the second rigid wheel (15) is provided with a first groove for mounting the flexible wheel (16) and the wave generator (17), and the first connecting portion (222) is in meshing connection with the flexible wheel (16).

4. The in-wheel motor drive assembly (100) according to claim 1, wherein the second rigid wheel (15) has a body portion (151) extending in a radial direction of the hub axle (10) and a second connecting portion (152) and a third connecting portion (153) extending from the body portion (151) in sequence in an axial direction of the hub axle (10), a side of the body portion (151) facing the first rigid wheel (22) is provided with a second groove for mounting the flexible wheel (16) and the wave generator (17), the second connecting portion (152) is engaged with the flexible wheel (16), and the third connecting portion (153) is engaged with the housing (6).

5. The in-wheel motor drive assembly (100) of claim 1, further comprising a stop (23), said stop (23) being fixed to said second rigid wheel (15) and abutting against said first rigid wheel (22) to limit relative axial displacement between said first rigid wheel (22) and said second rigid wheel (15).

6. The in-wheel motor drive assembly (100) according to claim 1, wherein the drive motor (30) comprises a stator (7), a rotor (5) and an output shaft (20) connected torque-proof to the rotor (5), the first rigid wheel (22), the second rigid wheel (15) and the output shaft (20) together defining an enclosed reducer cavity (A2).

7. The in-wheel motor drive assembly (100) of claim 6, wherein a first seal (24) is provided between the first rigid wheel (22) and the second rigid wheel (15), a second seal (21) is provided between the first rigid wheel (22) and the output shaft (20), and a third seal (18) is provided between the second rigid wheel (15) and the output shaft (20).

8. The in-wheel motor drive assembly (100) according to claim 6, further comprising a one-way clutch (19) arranged between the output shaft (20) and the wave generator (17) to cut off or enable a torque-resistant connection between the drive motor (30) and the speed reducer (40), the one-way clutch being provided with needle bearings (191, 192) radially inside and/or outside.

9. The in-wheel motor drive assembly (100) according to claim 6, wherein the rotor (5) and the hub axle (10) together define a closed motor cavity (A1), the motor cavity and the retarder cavity (A2) each being fluidly sealed, the rotor (5) being supported on the housing (6) via a third bearing (4, 13), the third bearing (4, 13) being a sealed bearing.

10. The in-wheel motor drive assembly (100) of claim 1, further comprising a grease injection mechanism (14) having a passage extending through the housing (6) and the second rigid gear (15) to provide grease to the speed reducer (40).

11. An electrically assisted vehicle fitted with an in-wheel motor drive assembly (100) as claimed in any one of claims 1 to 10.

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