Wheel hub motor and electric vehicle

Abstract

The application discloses a kind of wheel hub motor and electric vehicle, wheel hub motor includes middle shaft and is connected to the shell assembly of the middle shaft, stator assembly, rotor assembly and gear assembly, the shell assembly is supported on the middle shaft by first bearing, the rotor assembly is supported on the middle shaft by second bearing, the rotor assembly is driven connection with the shell assembly by the gear assembly, the side surface of the rotor assembly towards the gear assembly is provided with first accommodating slot, part gear assembly is placed in the first accommodating slot.Rotor assembly of wheel hub motor is driven shell assembly rotation by gear assembly, shell assembly is integrated with the wheel of electric vehicle, realize the travel of electric vehicle.Wheel hub motor is realized deceleration and improvement torque by gear assembly, in axial direction, using the first accommodating slot of rotor assembly accommodates part gear assembly, reduce the axial dimension of wheel hub motor, reduce the space requirement of wheel hub motor, expand the range of use.

Description

Technical Field

[0001] The present invention relates to the technical field of motors, and in particular to a hub motor and an electric vehicle. Background Art

[0002] With the development of technology, miniaturization and high power density of hub motors have become a development trend. Existing hub motors generally have the disadvantages of large size and weight, and insufficient power density. In related technologies, electric vehicles use hub motors to directly drive the wheels. Some hub motors have a reduction mechanism to reduce the speed, increase the torque and power density of the motor. However, after adding the reduction mechanism, the reduction mechanism occupies more axial space, resulting in a larger axial dimension of the hub motor. This is only suitable for hub motors with large axial dimensions, and its scope of use is limited. Therefore, making full use of the space inside the motor and developing a hub motor with a small axial dimension and gears has broad application prospects. Summary of the Invention

[0003] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention provides a hub motor with a compact axial layout and a wide range of applications.

[0004] The present invention also provides an electric vehicle having the above-mentioned hub motor.

[0005] According to an embodiment of the first aspect of the present invention, the hub motor includes a central shaft and a housing assembly, a stator assembly, a rotor assembly and a gear assembly connected to the central shaft. The housing assembly is supported on the central shaft by a first bearing, and the rotor assembly is supported on the central shaft by a second bearing. The rotor assembly and the housing assembly are transmission-connected via the gear assembly. A first accommodating groove is provided on the side of the rotor assembly facing the gear assembly, and at least a portion of the gear assembly is placed in the first accommodating groove.

[0006] The in-wheel motor according to the first embodiment of the present invention has at least the following beneficial effects: the rotor assembly of the in-wheel motor drives the housing assembly to rotate via the gear assembly, and the housing assembly is integrally connected to the wheel of the electric vehicle, enabling the electric vehicle to travel. The in-wheel motor uses the gear assembly to reduce speed and increase torque. In the axial direction, the first receiving groove of the rotor assembly accommodates at least a portion of the gear assembly, reducing the axial size of the in-wheel motor, reducing the space required by the in-wheel motor, and expanding its range of applications.

[0007] According to some embodiments of the first aspect of the present invention, the gear assembly includes a sun gear, three planetary gears, a planetary carrier and an inner ring gear, the sun gear is fixedly connected to the rotor assembly, the planetary carrier is fixedly connected to the central shaft, the planetary gears are rotatably connected to the planetary carrier, the inner ring gear is fixedly connected to the housing assembly, the planetary gears are simultaneously engaged with the sun gear and the inner ring gear, and part of the planetary gears and part of the inner ring gear are placed in the first accommodating groove.

[0008] According to some embodiments of the first aspect of the present invention, a second accommodating groove is provided on a side of the stator assembly facing the rotor assembly, and a portion of the first accommodating groove is located within the second accommodating groove.

[0009] According to some embodiments of the first aspect of the present invention, a third accommodating groove is provided on the side of the rotor assembly facing the stator assembly, and the stator assembly has a plurality of windings uniformly distributed circumferentially, and the windings are placed in the third accommodating groove.

[0010] According to some embodiments of the first aspect of the present invention, the planetary gear comprises a coaxial large gear and a small gear, the large gear meshes with the sun gear, and the small gear meshes with the inner ring gear.

[0011] According to some embodiments of the first aspect of the present invention, the housing assembly includes a first end cover, a second end cover and a rim, the first end cover and the second end cover are connected on both sides of the rim, the second end cover is provided with a gear housing, and the gear assembly is located in the inner cavity of the gear housing.

[0012] According to some embodiments of the first aspect of the present invention, an inwardly contracted connecting portion is provided at the end of the gear housing, the inner ring gear is connected to the connecting portion, and a portion of the connecting portion is placed in the first accommodating groove.

[0013] According to some embodiments of the first aspect of the present invention, the second end cover is provided with an opening communicating with the inner cavity, and the second end cover is connected to a surface cover covering the opening.

[0014] According to some embodiments of the first aspect of the present invention, the outer circumference of the surface cover is circular, and the second end cover is provided with a positioning groove for accommodating the surface cover, and the positioning groove matches the outer shape of the surface cover.

[0015] According to some embodiments of the first aspect of the present invention, the rotor assembly is provided with a bearing seat, and the bearing seat is connected to two second bearings, and the two second bearings are distributed at intervals along the axial direction of the central axis.

[0016] According to the second embodiment of the present invention, the electric vehicle includes the hub motor described in the first embodiment. The hub motor achieves deceleration and increases torque through a gear assembly. In the axial direction, the first accommodating groove of the rotor assembly is used to accommodate part of the gear assembly, thereby reducing the axial size of the hub motor and reducing the space requirement of the hub motor. The electric vehicle is suitable for various models of electric vehicles.

[0017] Additional aspects and advantages of the present invention will be set forth in part in the description which follows and, in part, will be obvious from the description which follows, or may be learned by practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Additional aspects and advantages of the present invention will become apparent and readily understood from the following description of embodiments with reference to the accompanying drawings, in which:

[0019] Figure 1 This is a schematic structural diagram of a hub motor according to an embodiment of the first aspect of the present invention;

[0020] Figure 2 A cross-sectional view of a hub motor according to an embodiment of the first aspect of the present invention;

[0021] Figure 3 for Figure 2 A partial enlarged view of point A in the middle;

[0022] Figure 4 It is a partial enlarged view of the gear assembly, the rotor assembly and the stator assembly in the embodiment of the first aspect of the present invention;

[0023] Figure 5 This is a structural schematic diagram of the hub motor without the housing assembly according to the first aspect of the present invention;

[0024] Figure 6 2 is a schematic structural diagram of a gear assembly in an embodiment of the first aspect of the present invention;

[0025] Figure 7 This is a structural schematic diagram of the gear assembly without the planet carrier in the embodiment of the first aspect of the present invention;

[0026] Figure 8 This is a front view of the gear assembly in the embodiment of the first aspect of the present invention without the planet carrier.

[0027] The accompanying figures are as follows:

[0028] Central shaft 100, first bearing 110, second bearing 120;

[0029] Housing assembly 200, first end cover 210, second end cover 220, gear housing 221, connecting portion 222, positioning groove 223, opening 224, rim 230, surface cover 240, outer sleeve 241, inner sleeve 242;

[0030] stator assembly 300, second accommodating slot 301, winding 310, stator core 320, tooth portion 321;

[0031] Rotor assembly 400, first accommodating groove 401, third accommodating groove 402, rotor overmolded part 410, guide hole 411, rib 412, bearing seat 420;

[0032] Gear assembly 500 , sun gear 510 , planetary gears 520 , large gear 521 , small gear 522 , planet carrier 530 , gear shaft 531 , third bearing 532 , inner ring gear 540 , and notch 541 . DETAILED DESCRIPTION

[0033] The following describes embodiments of the present invention in detail. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended only to explain the present invention and are not to be construed as limiting the present invention.

[0034] In the description of the present invention, it should be understood that descriptions involving orientations, such as up, down, front, back, left, right, etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they cannot be understood as limitations on the present invention.

[0035] In the description of the present invention, if there is a description of first and second, it is only for the purpose of distinguishing the technical features, and cannot be understood as indicating or implying the relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.

[0036] In the description of the present invention, unless otherwise clearly defined, terms such as setting, installing, and connecting should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above terms in the present invention based on the specific content of the technical solution.

[0037] In related technologies, electric vehicles use in-wheel motors as their power components. Their design integrates the powertrain, transmission, and braking systems. By integrating the motor's housing and wheel rim into a single structure, and integrating a reduction mechanism within the motor, the rotor rotates the housing through the reduction mechanism, which reduces speed and increases torque. However, the reduction mechanism occupies a large space, particularly in the axial direction, resulting in a larger axial dimension for the motor, limiting its practicality and requiring improvement.

[0038] like Figures 1 to 4As shown, an embodiment of the first aspect of the present invention provides a hub motor for an electric vehicle. The hub motor includes a central shaft 100, a housing assembly 200, a stator assembly 300, a rotor assembly 400, and a gear assembly 500 mounted on the central shaft 100. The central shaft 100 is typically connected to the frame of the electric vehicle and serves as a mounting base. The housing assembly 200 includes a first end cap 210, a second end cap 220, and a rim 230. The first end cap 210 and the second end cap 220 are positioned on either side of the rim 230 and are both fixed to the rim 230 by screws, facilitating assembly and disassembly and maintenance. A first bearing 110 and a second bearing 120 are mounted on the central shaft 100. The first end cap 210 and the second end cap 220 are rotatably connected to the central shaft 100 via the first bearing 110. The rotor assembly 400 is rotatably connected to the central shaft 100 via the second bearing 120, and both can rotate relative to the central shaft 100.

[0039] It can be understood that the rotor assembly 400 and the second end cover 220 of the shell assembly 200 are connected in transmission through the gear assembly 500. That is, when the hub motor is running, the rotor assembly 400 drives the shell assembly 200 to rotate through the gear assembly 500. The rim 230 of the shell assembly 200 is part of the wheel of the electric vehicle. The rim 230 directly drives the wheel to rotate, thereby realizing the driving of the electric vehicle.

[0040] Considering that the gear assembly 500 is mounted on the central axle 100 and occupies a certain amount of space in the axial direction of the central axle 100, a first receiving groove 401 is provided on the rotor assembly 400. The first receiving groove 401 is located on the side of the rotor assembly 400 facing the gear assembly 500. The first receiving groove 401 can accommodate a portion of the gear assembly 500. For example, along the radial direction of the central axle 100, the width of the first receiving groove 401 is greater than the size of the portion of the gear assembly 500. Placing the portion of the gear assembly 500 in the first receiving groove 401 creates a more compact layout, which can reduce the axial size of the hub motor. Of course, the entire gear assembly 500 can also be placed in the first receiving groove 401. In the axial direction, the first receiving groove 401 of the rotor assembly 400 is used to accommodate at least a portion of the gear assembly 500, thereby reducing the axial size of the hub motor, reducing the space required by the hub motor, and expanding its scope of use.

[0041] Reference Figures 5 to 8The gear assembly 500 includes a sun gear 510, a planet carrier 530 and an inner ring gear 540. The planet carrier 530 is provided with three gear shafts 531, and the three gear shafts 531 are evenly distributed around the sun gear 510. A planet gear 520 is installed on each gear shaft 531. A third bearing 532 is provided between the gear shaft 531 and the planet gear 520, and the rotation of the planet gear 520 is achieved by the support of the third bearing 532. The sun gear 510 is fixedly connected to the rotor assembly 400, the planet carrier 530 is fixedly connected to the central shaft 100, the inner ring gear 540 is fixedly connected to the housing assembly 200, and the three planetary gears 520 revolve around the sun gear 510, and the sun gear 510 and the inner ring gear 540 are simultaneously engaged with the planetary gears 520. The rotor assembly 400 drives the sun gear 510 to rotate, and the sun gear 510 drives the three planetary gears 520 to rotate. Since the planet carrier 530 is fixed, the three planetary gears 520 drive the inner ring gear 540 and the housing assembly 200 to rotate, and the rim 230 of the housing assembly 200 drives the wheels of the electric vehicle to rotate, so that the hub motor directly drives the wheels to rotate, thereby realizing the driving of the electric vehicle.

[0042] It will be appreciated that gear assembly 500 is a planetary gear transmission system. Compared to conventional gear transmissions, planetary gear transmissions offer the advantages of a larger transmission ratio and a smaller size. Therefore, planetary gear transmission systems are widely used in speed reducers, speed increasers, and transmissions in various mechanical transmission systems. Gear assembly 500 utilizes a planetary gear transmission system and is integrated into an in-wheel motor, making the in-wheel motor compact and facilitating its miniaturization.

[0043] Taking into account that the inner ring gear 540 is located on the outer periphery of the gear assembly 500, part of the inner ring gear 540 and part of the planetary gear 520 are placed in the first accommodating groove 401. The inner wall of the first accommodating groove 401 surrounds the gear assembly 500 to prevent the structure of the rotor assembly 400 from interfering with the gear assembly 500, which is conducive to the smooth operation of the hub motor.

[0044] Reference Figure 7 and Figure 8 Planetary gear 520 is a duplex gear. A duplex gear is a structure consisting of two coaxial gears spaced a certain distance apart. Its function is to change the output shaft's rotational speed. Planetary gear 520 includes a large gear 521 with a larger number of teeth and a small gear 522 with a smaller number of teeth. Large gear 521 meshes with sun gear 510, while small gear 522 meshes with annular gear 540. Large gear 521 has a larger number of teeth than sun gear 510, achieving a first-stage reduction. Annular gear 540 has a larger number of teeth than small gear 522, achieving a second-stage reduction. Therefore, gear assembly 500 has two stages of reduction, achieving a larger reduction ratio within a compact size while simultaneously increasing output torque, which facilitates faster electric vehicle acceleration.

[0045] Reference Figure 4 The rotor assembly 400 includes a bearing seat 420. Two bearing chambers are formed within the bearing seat 420. A second bearing 120 is mounted in each bearing chamber. A spacer is provided between the two second bearings 120 to maintain a fixed axial position. Using two second bearings 120 to support the rotor assembly 400 improves the rotational stability of the rotor assembly 400 and the reliability of the hub motor. Using two second bearings 120 allows for a smaller model, improving structural compactness and reducing the outer diameter of the bearing seat 420. Since the outer diameter of the pinion 522 is smaller than that of the gear 521, space exists on the outer periphery of the pinion 522. The bearing seat 420 can fit into this space on the outer periphery of the pinion 522, creating a more compact axial layout and reducing the axial dimension. Furthermore, the radial space of the first accommodating groove 401 is increased to accommodate the gear assembly 500.

[0046] Reference Figure 3 As will be appreciated, the second end cap 220 of the housing assembly 200 is provided with a gear housing 221. The inner cavity of the gear housing 221 accommodates the gear assembly 500, providing protection and position limiting. The end of the gear housing 221 is provided with an inwardly contracting connecting portion 222. The inner gear ring 540 is mounted on the inner wall of the connecting portion 222. The connecting portion 222 extends into the first accommodating groove 401, meeting the nesting requirements and reducing axial space.

[0047] It can be understood that the sun gear 510, planetary gears 520 and inner ring gear 540 of the gear assembly 500 are all coated with grease to reduce wear, and the gear housing 221 extends into the first accommodating groove 401, that is, the gear housing 221 and the rotor assembly 400 are staggered in the axial direction, which can block the grease that is thrown away, promote the grease to flow back, and continue to lubricate the sun gear 510, planetary gears 520 and inner ring gear 540 of the gear assembly 500.

[0048] It is understandable that the inner gear ring 540 is fixedly mounted on the inner wall of the gear housing 221 and can be fixed by interference fit or by bolts. Figure 8 As shown, the outer wall of the inner gear ring 540 is provided with a notch 541, and the inner wall of the gear housing 221 is provided with a protrusion (not shown in the figure) that matches the notch 541. During assembly, the protrusion is used to fit into the notch 541 for accurate positioning and prevent the inner gear ring 540 from rotating relative to the gear housing 221, thereby improving reliability.

[0049] It can be understood that since the first accommodating groove 401 is recessed, the inner wall edge of the first accommodating groove 401 forms a step, and the gear housing 221 is configured to match the shape of the step, so that a gap is formed between the gear housing 221 and the rotor assembly 400 to prevent interference during rotation. In addition, there is a bend in the surface of the gear housing 221, which is beneficial to improving structural strength and stability.

[0050] Reference Figure 1 and Figure 2 As will be appreciated, an opening 224 is provided at the center of the second end cap 220. The opening 224 communicates with the inner cavity of the gear housing 221. The maximum diameter of the opening 224 is greater than the maximum diameter of the gear assembly 500, allowing the entire gear assembly 500 to enter and exit through the opening 224. A removable cover 240 is connected to the second end cap 220, covering the opening 224 and thereby preventing the gear assembly 500 from being exposed. During subsequent maintenance, the cover 240 can be removed to inspect the gear assembly 500 through the opening 224, add grease, and perform other operations. The entire gear assembly 500 or individual components of the gear assembly 500 can also be removed through the opening 224 for replacement, greatly improving convenience and reducing time consumption.

[0051] It is understandable that the cover 240 is fixedly connected to the second end cover 220 by bolts to meet the needs of disassembly and assembly, and eight bolts are evenly distributed around the circumference to improve the stability of the structure. Of course, the cover 240 can also be connected to the second end cover 220 by a buckle, or a buckle-fit bolt structure can be used. Figure 2 As shown, the surface cover 240 is provided with an outer sleeve 241 surrounding the central axis 100, and an inner sleeve 242 is provided inside the outer sleeve 241. The inner wall of the inner sleeve 242 forms a bearing chamber to cooperate with the first bearing 110. By providing the outer sleeve 241 and the inner sleeve 242, it is convenient to cooperate with the installation of the first bearing 110, and the structural strength of the surface cover 240 can be improved, thereby improving reliability.

[0052] It can be understood that the cover 240 is the intermediate link for transmitting the force of the rim 230 to the central shaft 100. The cover 240 is connected to the first bearing 110 on the central shaft 100 through the inner sleeve 242, and the cover 240 and the second end cover 220 adopt a nested structure. The shape of the cover 240 is circular, and a positioning groove 223 is set on the second end cover 220. The positioning groove 223 matches the shape of the cover 240. During assembly, the cover 240 is embedded in the positioning groove 223, and the outer wall of the cover 240 abuts the inner wall of the positioning groove 223, which not only achieves accurate positioning, but also achieves force support and improves structural stability. Figure 2 As shown, the thickness of the cover 240 is greater than the depth of the positioning groove 223. After assembly, part of the cover 240 protrudes from the second end cover 220. Using a thicker cover 240 is conducive to transmitting force and reducing the risk of deformation.

[0053] Reference Figures 2 to 4 The stator assembly 300 is provided with a second accommodating groove 301, which is located on the side of the stator assembly 300 facing the rotor assembly 400. Part of the first accommodating groove 401 is embedded in the second accommodating groove 301, and part of the gear assembly 500 is embedded in the first accommodating groove 401. The gear assembly 500, the rotor assembly 400 and the stator assembly 300 form a double nested structure in the axial direction, further reducing the axial size of the hub motor.

[0054] Reference Figures 2 to 4 The stator assembly 300 includes a winding 310 and a stator core 320. The outer periphery of the stator core 320 is provided with a plurality of circumferentially evenly distributed teeth 321, and the winding 310 is wound around the teeth 321. To reduce the axial dimension of the in-wheel motor, a stator core 320 with a smaller axial dimension is used. However, the axial dimension of the winding 310 cannot be reduced accordingly. Therefore, a third accommodating groove 402 is provided in the rotor assembly 400, and a portion of the winding 310 is embedded in the third accommodating groove 402. This brings the stator assembly 300 and the rotor assembly 400 closer together, resulting in a more compact structure and facilitating a reduction in the axial dimension of the in-wheel motor.

[0055] Reference Figure 5 As will be appreciated, the primary component of rotor assembly 400 is rotor overmold 410. Rotor overmold 410, by integrally encapsulating the yoke (not shown) and permanent magnets (not shown) during the injection molding process, facilitates manufacturing and reduces costs. Rotor assembly 400 employs an integrated structure, with rotor overmold 410 encapsulating the yoke and permanent magnets to secure them, preventing the permanent magnets from falling off. This improves the reliability of rotor assembly 400 and contributes to the lifespan of the in-wheel motor.

[0056] It is understood that the rotor overmolded part 410 is provided with a plurality of guide holes 411, which are evenly distributed along the circumference of the rotor overmolded part 410. The guide holes 414 are connected to the third accommodating slot 402. In the radial direction, the guide holes 411 correspond to the positions of the windings 310. When the rotor assembly 400 rotates at high speed, the guide holes 411 serve as channels for airflow, connecting both sides of the rotor overmolded part 410. The airflow flows into the inner cavity of the housing assembly 200. The first end cap 210 and the second end cap 220 of the housing assembly 200 are typically metal parts, such as aluminum alloy parts, which have great structural strength and excellent heat transfer performance. The airflow contacts the first end cap 210 and the second end cap 220, and dissipates heat to the external space of the hub motor through the first end cap 210 and the second end cap 220.

[0057] like Figure 5As shown, the outer periphery of the rotor overmolded component 410 is also provided with a plurality of circumferentially evenly distributed ribs 412. These ribs 412 act as reinforcements, increasing the structural strength and rigidity of the rotor assembly 400 and reducing wobble during rotation. A rib 412 is located on either side of each air guide hole 411. When the rotor assembly 400 rotates at high speed, the ribs 412 drive airflow, forming an air circulation loop within the in-wheel motor in conjunction with the air guide holes 411. This enhances air convection within the in-wheel motor, effectively dissipating heat generated by the windings 310, improving the in-wheel motor's heat dissipation performance, and reducing the in-wheel motor's temperature rise, thereby ensuring stable output efficiency and meeting the in-wheel motor's load-carrying requirements.

[0058] The electric vehicle provided in the second embodiment of the present invention includes the in-wheel motor of the first embodiment. The in-wheel motor includes a central axis 100 and a housing assembly 200, a stator assembly 300, a stator assembly 300, and a gear assembly 500 connected to the central axis 100. The central axis 100 is typically connected to the frame of the electric vehicle and serves as a mounting base. The housing assembly 200 includes a first end cap 210, a second end cap 220, and a rim 230. The first end cap 210 and the second end cap 220 are disposed on either side of the rim 230. The first end cap 210 and the second end cap 220 are both fixed to the rim 230 by screws, facilitating assembly and disassembly and maintenance. A first bearing 110 and a second bearing 120 are mounted on the central axis 100. The first end cap 210 and the second end cap 220 are rotatably connected to the central axis 100 via the first bearing 110. The rotor assembly 400 is rotatably connected to the central axis 100 via the second bearing 120, and both can rotate relative to the central axis 100.

[0059] The gear assembly 500 is mounted on the central axle 100 and occupies a certain amount of space in the axial direction of the central axle 100. Therefore, a first receiving groove 401 is provided in the rotor assembly 400. The first receiving groove 401 is located on the side of the rotor assembly 400 facing the gear assembly 500. The first receiving groove 401 can accommodate a portion of the gear assembly 500. Along the radial direction of the central axle 100, the width of the first receiving groove 401 is greater than the size of the portion of the gear assembly 500. The gear assembly 500 extends into the first receiving groove 401, creating a more compact layout and reducing the axial size of the hub motor. In the axial direction, the first receiving groove 401 of the rotor assembly 400 accommodates at least a portion of the gear assembly 500, thereby reducing the axial size of the hub motor, reducing the space required by the hub motor, and expanding its range of applications.

[0060] The embodiments of the present invention are described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Various changes can be made within the scope of knowledge possessed by ordinary technicians in the relevant technical field without departing from the spirit of the present invention.

Claims

1. Hub motor, characterized in that: include: central axis; a housing assembly supported on the central shaft via a first bearing; a stator assembly fixedly connected to the central shaft; a rotor assembly supported on the central shaft via a second bearing; A gear assembly, the gear assembly comprising a sun gear, planet gears, a planet carrier, and an inner ring gear, the sun gear being fixedly connected to the rotor assembly, the planet carrier being fixedly connected to the central shaft, the planet gears being rotatably connected to the planet carrier, the inner ring gear being fixedly connected to the housing assembly, the planet gears comprising a coaxial large gear and a small gear, the small gear being arranged on a side facing the rotor assembly, the large gear meshing with the sun gear, and the small gear meshing with the inner ring gear, a first accommodating groove being provided on a side of the rotor assembly facing the gear assembly, at least a portion of the planet gears and a portion of the inner ring gear being placed in the first accommodating groove; A third accommodating groove is provided on the side of the rotor assembly facing the stator assembly, and the third accommodating groove is located on the outer periphery of the first accommodating groove. The stator assembly has a plurality of windings uniformly distributed in the circumferential direction, and the windings are placed in the third accommodating groove; The rotor assembly is provided with a bearing seat, which is protruded in the first accommodating groove. The stator assembly is provided with a second accommodating groove on the side facing the rotor assembly. Part of the first accommodating groove is located in the second accommodating groove. Along the axial direction of the central axis, the bearing seat and the pinion are staggered.

2. The hub motor according to claim 1, characterized in that: The number of the planetary gears is three.

3. The hub motor according to claim 2, characterized in that: The housing assembly includes a first end cover, a second end cover and a rim. The first end cover and the second end cover are connected to both sides of the rim. The second end cover is provided with a gear housing. The gear assembly is located in the inner cavity of the gear housing.

4. The hub motor according to claim 3, characterized in that: An inwardly contracted connecting portion is provided at the end of the gear housing, the inner gear ring is connected to the connecting portion, and a portion of the connecting portion is placed in the first accommodating groove.

5. The hub motor according to claim 3, characterized in that: The second end cover is provided with an opening communicating with the inner cavity, and the second end cover is connected to a surface cover covering the opening.

6. The hub motor according to claim 5, characterized in that: The second end cover is provided with a positioning groove for accommodating the surface cover, and the positioning groove matches the shape of the surface cover.

7. The hub motor according to claim 1, characterized in that: The bearing seat is connected to two second bearings, and the two second bearings are distributed at intervals along the axial direction of the central shaft.

8. An electric vehicle, characterized in that The invention comprises the hub motor according to any one of claims 1 to 7.

Images