Hub motor

Abstract

The invention relates to the technical field of new energy automobiles, in particular to a hub motor which comprises a rotor assembly, a stator assembly, an oil cooling mechanism and a water cooling mechanism, the stator assembly comprises a stator iron core and an armature winding wound around the stator iron core, the stator iron core is installed outside a motor shaft, and the oil cooling mechanism comprises at least two oil cooling branches distributed at intervals in the axial direction of the stator iron core. The at least one oil cooling branch is used for spraying cooling oil to one end part of the armature winding, and the at least one oil cooling branch supplies the cooling oil to the stator iron core so as to cool the stator iron core. The plurality of oil cooling branches are used for respectively cooling the end parts of the stator core and the armature winding, and a heating source with relatively high heating value in the hub motor is effectively cooled, so that the heating is reduced, the torque / power density of the hub motor is increased, the weight of the hub motor is effectively reduced through efficient heat management under the condition of the same output requirement, and the service life of the hub motor is prolonged. Therefore, the unsprung mass of the vehicle is reduced, and key indexes such as stability, comfort and acceleration of the vehicle can be improved.

Description

Technical Field

[0001] The present invention relates to the technical field of new energy vehicles, and in particular to a wheel hub motor. Background Art

[0002] As new energy vehicles have been rapidly marketized in my country, various new technologies have emerged in new energy vehicles, and modular intelligent chassis is one of the new technologies. A preferred technical route for modular intelligent chassis is to integrate the hub motor inside the wheel rim, eliminating the reduction mechanism, releasing a large amount of chassis space, and making the vehicle body layout more flexible. The hub motor installed inside the wheel rim will increase the unsprung mass of the vehicle, thereby reducing key indicators such as vehicle stability, comfort, and acceleration. Therefore, how to reduce the weight of the hub motor under the same power / torque conditions is a technical difficulty that limits the application of hub motors. In addition to reducing motor losses through the application of new motor materials, such as amorphous materials, efficient thermal management design is an important technical route to increase the torque / power density of the hub motor and reduce the weight of the hub motor under the same material usage.

[0003] The thermal management of the hub motor includes the cooling of the hub motor. The existing cooling methods include forced air cooling, water cooling and oil cooling. However, the working environment of the hub motor is harsh and the heat sources are diverse. The existing cooling structure often only takes into account a part of the heat sources of the hub motor, resulting in the existing cooling method being unsatisfactory. The hub motor cannot be effectively cooled, resulting in a large amount of energy loss during operation of the hub motor and the inability to output energy efficiently. In other words, the torque / power density of the hub motor is low, and the purpose of effectively reducing the weight of the hub motor through efficient thermal management of the hub motor cannot be achieved. Summary of the invention

[0004] The object of the present invention is to provide a hub motor, which optimizes the thermal management of the hub motor by improving the cooling structure, so as to solve the above-mentioned problem that the thermal management effect of the existing hub motor is not reasonable enough.

[0005] To achieve the above-mentioned purpose, the technical solution of the present invention is: a hub motor, comprising a rotor assembly, a stator assembly, and an oil cooling and water cooling mechanism, wherein the rotor assembly is used to be installed inside a wheel rim, the stator assembly is installed on the inner side of the rotor assembly, the stator assembly comprises a stator core and an armature winding wound around the stator core, the stator core is installed outside the motor shaft, and the armature winding comprises two end portions protruding from the stator core along the axial direction of the stator core; the oil cooling mechanism comprises at least two oil cooling branches spaced apart along the axial direction of the stator core, at least one of the oil cooling branches sprays cooling oil to one end of the armature winding through an oil spray port arranged in the oil cooling branch, and at least one of the oil cooling branches supplies cooling oil to the stator core to cool the stator core.

[0006] In one embodiment, the oil cooling branch includes two end oil cooling branches and a middle oil cooling branch. Along the axial direction of the stator core, the middle oil cooling branch is arranged between the two end oil cooling branches. The two end oil cooling branches are respectively used to spray cooling oil to one end of the armature winding, and the middle oil cooling branch is used to supply cooling oil to the stator core.

[0007] In one embodiment, the oil cooling mechanism includes an oil inlet circuit arranged on the motor shaft, each of the oil cooling branches is respectively connected to the oil inlet circuit, the end oil cooling branch includes a first branch section connected to the oil inlet circuit and extending radially along the motor shaft, and a second branch section arranged radially outside the motor shaft, the oil spray port is arranged in the second branch section, and the second branch section is arranged on the outside of the end of the armature winding along the axial direction of the motor shaft, so that the oil spray port of the second branch section sprays cooling oil toward one end of the armature winding.

[0008] In one embodiment, the second branch section extends along the circumference of the motor shaft, and the second branch section is formed by an arc-shaped bend pipe extending along the circumference of the motor shaft, and a plurality of the fuel injection ports are provided, and the plurality of the fuel injection ports are arranged along the extension direction of the arc-shaped bend pipe.

[0009] In one embodiment, the oil cooling mechanism includes an oil inlet circuit arranged on the motor shaft, and the middle oil cooling branch includes a third branch section connected to the oil inlet circuit and a fourth branch section extending along the circumference of the stator core, and the fourth branch section is arranged on the inner side of the stator core for cooling the inner side of the stator core.

[0010] In one embodiment, the middle oil cooling branch also includes a fifth branch section extending axially along the stator core, the fifth branch section is formed by a plurality of grooves formed on the inner wall of the stator core, and the plurality of grooves are arranged at intervals along the circumference of the stator core and connected to the fourth branch section; the grooves penetrate the stator core axially along the stator core.

[0011] In one embodiment, a water cooling mechanism is further included, and the water cooling mechanism includes a water jacket arranged between the motor shaft and the stator core, and an S-shaped water channel is provided inside the water jacket. The third branch section of the middle oil cooling branch is passed through the gap of the water channel, and the fourth branch section of the middle oil cooling branch is formed by an annular groove arranged around the outer wall of the water jacket.

[0012] In one embodiment, the oil cooling mechanism includes an oil inlet circuit, an oil outlet circuit and an oil collecting chamber. The oil inlet circuit is arranged on the motor shaft, defining the direction of gravity to which the hub motor is subjected when in use as downward, and the opposite direction as upward. The oil cooling branch extends upward from the oil inlet circuit, and the oil collecting chamber is arranged below the oil cooling branch, so that the cooling oil flowing out of the oil cooling branch is gathered in the oil collecting chamber under the action of gravity and leaves the hub motor through the oil outlet circuit.

[0013] In one embodiment, a water cooling mechanism is further included, and the water cooling mechanism includes a water jacket arranged between the motor shaft and the stator core.

[0014] In one embodiment, an S-shaped water channel is provided inside the water jacket, and the water channel surrounds the outside of the motor shaft. The water channel is divided into a first water cooling branch and a second water cooling branch distributed on both sides of the radial section along a radial section of the motor shaft, and the water inlet ends of the first water cooling branch and the second water cooling branch are connected to the same water inlet waterway, and the water outlet ends of the first water cooling branch and the second water cooling branch are connected to the same water outlet waterway.

[0015] The beneficial effects of the present invention are: 1. The present invention cools the ends of the stator core and the armature winding respectively by setting a plurality of oil cooling branches, so as to effectively cool the heat source with a large heat generation in the wheel hub motor, thereby reducing the heat generation of the wheel hub motor, reducing the energy loss of the wheel hub motor, and then increasing the energy output of the wheel hub motor under the same energy input, that is, increasing the torque / power density of the wheel hub motor, and effectively reducing the weight of the wheel hub motor through efficient thermal management under the same output demand, thereby reducing the unsprung mass of the vehicle, which is beneficial to improving the key indicators of the vehicle such as stability, comfort, acceleration, etc.

[0016] 2. The end oil cooling branch sprays cooling oil to the end of the armature winding through the oil spray port, so that the cooling area of ​​the armature winding by the cooling oil is larger, and the cooling oil in the middle oil cooling branch flows out through the end of the groove set on the inner side of the stator core. In order to facilitate the circulation of the cooling oil, the cooling oil flowing out from the oil spray port and the two ends of the groove is collected by the oil collecting chamber below.

[0017] 3. The fourth branch section and the fifth branch section of the middle oil cooling branch cooperate to distribute the cooling oil along the axial and circumferential directions on the inner side of the stator core, so that the cooling area of ​​the stator core by the cooling oil is larger, which is beneficial to improving the cooling effect of the stator core.

[0018] 4. The oil cooling mechanism and the water cooling mechanism cooperate to further improve the cooling effect of the hub motor and optimize its thermal management method. The fourth branch section of the middle oil cooling branch is arranged in the S-shaped water channel gap to make full use of the limited space of the hub motor to achieve a compact layout. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 4 is a front view of a hub motor according to an embodiment of the present invention.

[0020] Figure 2 yes Figure 1 AA section view.

[0021] Figure 3 1 is a structural diagram of an oil cooling mechanism according to an embodiment of the present invention.

[0022] Figure 4 It is a structural diagram of the motor shaft and part of the oil circuit of the oil cooling mechanism according to an embodiment of the present invention.

[0023] Figure 5 1 is a structural diagram of a stator assembly according to an embodiment of the present invention.

[0024] Figure 6 4 is a structural diagram of a stator core according to an embodiment of the present invention.

[0025] Figure 7 yes Figure 2 The partial parts structure diagram from the BB cross-sectional perspective shows the second water-cooling branch structure.

[0026] Figure 8 yes Figure 1 CC cross-sectional view.

[0027] Fig. 9 1 is a structural diagram of a water cooling mechanism according to an embodiment of the present invention.

[0028] Fig.10 It is a schematic diagram of the cooling water flow direction of the water cooling mechanism of an embodiment of the present invention.

[0029] Among them: 1 rotor assembly, 11 housing, 111 rear housing, 112 main housing, 113 front housing, 12 rotor core, 2 stator assembly, 21 stator core, 211 groove, 22 armature winding, 3 motor shaft, 4 bearing, 50 oil cooling branch, 501 oil injection port, 51 end oil cooling branch, 511 first branch section, 512 second branch section, 52 middle oil cooling branch, 521 third branch section, 522 The fourth branch section, 523 the fifth branch section, 53 the oil inlet circuit, 530 the oil inlet joint, 54 the oil outlet circuit, 540 the oil outlet joint, 541 the oil outlet channel, 542 the oil extraction pipe, 55 the oil collecting chamber, 6 the water jacket, 60 the annular groove, 61 the first water-cooling branch, 62 the second water-cooling branch, 63 the water inlet circuit, 631 the water inlet joint, 632 the water inlet channel, 64 the water outlet circuit, 641 the water outlet joint, 642 the water outlet channel. DETAILED DESCRIPTION

[0030] To further illustrate the various embodiments, the present invention provides drawings. These drawings are part of the disclosure of the present invention, which are mainly used to illustrate the embodiments and can be used in conjunction with the relevant descriptions in the specification to explain the operating principles of the embodiments. With reference to these contents, a person of ordinary skill in the art should be able to understand other possible implementations and advantages of the present invention. The components in the figures are not drawn to scale, and similar component symbols are generally used to represent similar components.

[0031] See also Figure 1 to Figure 2 As shown, the present invention discloses a wheel hub motor, including a rotor assembly 1 and a stator assembly 2. The rotor assembly 1 is used to be installed inside the wheel rim and locked with the wheel rim by wheel bolts, and the stator assembly 2 is installed on the inner side of the rotor assembly 1. When the wheel hub motor is installed inside the wheel rim, it is used to form a part of the chassis assembly of the new energy vehicle. The wheel hub motor can be used as an electric motor, converting electrical energy into mechanical energy that can directly drive the wheel; the driving wheel hub motor can also be used as a generator, driven by the wheel to generate electrical energy to be recharged to the battery pack of the new energy vehicle.

[0032] The rotor assembly 1 includes a shell 11 and a rotor core 12 arranged in the shell 11. The shell 11 is spliced ​​by a rear shell 111, a main shell 112 and a front shell 113. The shell 11 is fixedly mounted on the rim 300, so that the rotor assembly 1 rotates synchronously with the wheel.

[0033] The stator assembly 2 is a non-rotating part. If there is no ambiguity, it is referred to as fixed. The stator assembly 2 includes a stator core 21 and an armature winding 22 wound on the stator core 21. The armature winding 22 includes two ends protruding from the stator core 21 along the axial direction of the stator core 21. The stator core 21 is installed outside the motor shaft 3. Bearings 4 that support the rotation of the rotor assembly 1 are installed at both ends of the motor shaft 3.

[0034] The thermal management of the wheel hub motor includes an oil cooling mechanism and a water cooling mechanism. The thermal management of the wheel hub motor is described in detail below.

[0035] See also Figures 2 to 7 As shown, the oil cooling mechanism includes three oil cooling branches 50 distributed at intervals along the axial direction of the stator core 21, namely two end oil cooling branches 51 and a middle oil cooling branch 52. Along the axial direction of the stator core 21, the middle oil cooling branch 52 is arranged between the two end oil cooling branches 51. The two end oil cooling branches 51 respectively spray cooling oil to one end of the armature winding 22 through the oil injection port 501, and the middle oil cooling branch 52 is used to supply cooling oil to the stator core 21.

[0036] The present invention cools the ends of the stator core 21 and the armature winding 22 respectively by setting a plurality of oil cooling branches 50. Since the armature winding 22 is wound on the stator core 21, the middle oil cooling branch 52 cools the stator core 21 and also cools the middle area between the two ends of the armature winding 22, thereby effectively cooling the armature winding 22 with a larger heat generation in the hub motor, thereby reducing the heat generation of the hub motor, reducing the energy loss of the hub motor, and further increasing the energy output of the hub motor under the same energy input, that is, increasing the torque / power density of the hub motor, and effectively reducing the weight of the hub motor through efficient thermal management under the same output demand, reducing the unsprung mass of the vehicle, which is beneficial to improving the key indicators of the vehicle such as stability, comfort, and acceleration.

[0037] The oil cooling mechanism also includes an oil inlet circuit 53 arranged on the motor shaft 3, each oil cooling branch 50 is respectively connected to the oil inlet circuit 53, and the two end oil cooling branches 51 are symmetrically arranged at the two ends of the armature winding 22. The following is explained by taking one of the end oil cooling branches 51 as an example.

[0038] The end oil cooling branch 51 includes a first branch section 511 connected to the oil inlet 53 and extending in the radial direction of the motor shaft 3, and a second branch section 512 arranged on the radial outer side of the motor shaft 3. The oil spray port 501 is arranged in the second branch section 512. The second branch section 512 is arranged on the outer side of the end of the armature winding 22 along the axial direction of the motor shaft 3, so that the oil spray port 501 of the second branch section 512 sprays cooling oil to one end of the armature winding 22. The two end oil cooling branches 51 cooperate to spray cooling oil to both ends of the armature winding 22, respectively, to cool the end of the armature winding 22, and reduce its heat generation and energy loss.

[0039] In this embodiment, the second branch section 512 extends along the circumference of the motor shaft 3, and the second branch section 512 is formed by an arc-shaped curved pipe extending along the circumference of the motor shaft 3, and a plurality of oil injection ports 501 are provided, and the plurality of oil injection ports 501 are arranged along the extension direction of the arc-shaped curved pipe. In order to allow the cooling oil to be accurately sprayed onto the end face of the end of the armature winding 22, the oil injection port 501 is arranged at an obliquely upper side of the arc-shaped curved pipe facing the armature winding 22, so that the oil injection port 501 sprays the cooling oil obliquely upward, thereby increasing the contact surface between the cooling oil and the armature winding 22.

[0040] In other embodiments, the second branch section 512 is not limited to extending along the circumferential direction of the motor shaft 3, but may also be formed by a pipe extending radially along the motor shaft 3, and the end of the pipe forms an oil injection port. This design can increase the diameter of the oil injection port, so that the cooling oil is more concentrated when it is sprayed out.

[0041] The middle oil cooling branch 52 includes a third branch section 521 connected to the oil inlet 53 and a fourth branch section 522 extending along the circumference of the motor shaft 3. The fourth branch section 522 is arranged on the inner side of the stator core 21 to cool the inner side of the stator core 21. The fourth branch section 522 extends along the circumference of the motor shaft 3 to spread the cooling oil along the inner side of the stator core 21 in an annular direction, which is beneficial to increase the contact area between the cooling oil and the stator core 21 and improve the cooling effect. The middle oil cooling branch 52 also includes a fifth branch section 523 extending along the axial direction of the stator core 21. The fifth branch section 523 is formed by a plurality of grooves 211 formed on the inner side wall of the stator core 21, and the plurality of grooves 211 are arranged at intervals along the circumference of the stator core 21 and connected to the fourth branch section 522. The existence of the fifth branch section 523 increases the space for the cooling oil to stay inside the stator core 21, and can design the cooling oil flow rate of the middle oil cooling branch 52 to be larger, thereby improving the cooling effect inside the stator core 21. In addition, the fourth branch section 522 and the fifth branch section 523 cooperate, and the cooling oil is distributed along the axial and circumferential directions inside the stator core 21, so that the cooling area of ​​the cooling oil on the stator core 21 is larger, which is conducive to further improving the cooling effect of the stator core 21, and at the same time improving the cooling effect of the middle area of ​​the armature winding 22.

[0042] The groove 211 of this embodiment penetrates the stator core 21 axially along the stator core 21 , so that both ends of the groove 211 form oil outlets of the middle oil cooling branch 52 , so that the cooling oil of the middle oil cooling branch 52 circulates.

[0043] The direction of gravity when the wheel hub motor is used (meaning installed on a car) is defined as downward, and the opposite direction is upward. The first branch section 511 and the third branch section 521 of this embodiment extend upward from the oil inlet passage 53, so as to supply cooling oil to the top and gradually spread to the lower part of the armature winding 22 under the action of gravity, thereby increasing the cooling area. In other embodiments, the first branch section 511 and the third branch section 521 may also be multiple cooling oil channels extending along the radial direction of the motor shaft 3, not limited to extending vertically upward from the oil inlet passage 53, but may also be multiple cooling oil channels extending obliquely upward from the oil inlet passage 53.

[0044] In order to facilitate the circulation of cooling oil, the oil cooling mechanism also includes an oil outlet passage 54 and an oil collecting chamber 55. The oil collecting chamber 55 is arranged below the oil cooling branch 50, so that the cooling oil flowing out of the oil cooling branch 50 is collected in the oil collecting chamber 55 under the action of gravity and leaves the hub motor through the oil outlet passage 54. The oil outlet passage 54 includes an oil outlet channel 541 arranged in the motor shaft 3 and an oil extraction pipe 542 extending into the oil collecting chamber 55. The oil extraction pipe 542 is connected to an oil extraction pump so as to extract the cooling oil in the oil collecting chamber 55 to the oil tank. The oil inlet passage 53 is also connected to an oil supply pump for supplying the cooling oil in the oil tank to the hub motor, thereby forming a cooling oil circulation loop.

[0045] The oil outlet passage 541 of the oil inlet passage 53 and the oil outlet passage 54 are both arranged in the motor shaft 3. In addition to utilizing the larger space of the motor shaft 3 to form a cooling oil circulation passage to optimize the layout of the hub motor, the cooling oil can also be used to cool the motor shaft 3.

[0046] The motor shaft 3 is further provided with an oil inlet joint 530 and an oil outlet joint 540 . The oil inlet joint 530 is communicated with the oil inlet oil circuit 53 , and the oil outlet joint 540 is communicated with the oil outlet channel 541 of the oil outlet oil circuit 54 .

[0047] The oil cooling branches 50 in the above embodiment are three, namely, two end oil cooling branches 51 and a middle oil cooling branch 52, but it is not limited thereto. The oil cooling branches 50 may be at least two, including an end oil cooling branch 51 and a middle oil cooling branch 52. In addition, the oil cooling branches 50 may be more than three, including two end oil cooling branches 51 and a plurality of middle oil cooling branches 52, and the plurality of middle oil cooling branches 52 are distributed at intervals along the axial direction of the stator core 21, so as to form multi-point cooling in the axial direction of the stator core 21.

[0048] See also Figures 8 to 10As shown, the water cooling mechanism includes a water jacket 6 surrounding the outer side of the motor shaft 3, and an S-shaped water channel is provided inside the water jacket 6. The water jacket 6 is arranged between the motor shaft 3 and the stator core 21, so as to cool the outer side of the motor shaft 3 and the inner side of the stator core 21. The water channel of the water jacket 6 surrounds the outside of the motor shaft 3, and the water channel is divided into a first water cooling branch 61 and a second water cooling branch 62 distributed on both sides of the radial section along a radial section of the motor shaft. The water inlet ends of the first water cooling branch 61 and the second water cooling branch 62 are connected to the same water inlet water channel 63, and the water outlet ends of the first water cooling branch 61 and the second water cooling branch 62 are connected to the same water outlet water channel 64.

[0049] The radial section refers to a section parallel to the main axis of the motor shaft 3 and passing through the diameter of the motor shaft 3. The diameter associated with the radial section in this embodiment is a diameter extending in the up-down direction, and the water inlet channel 63 and the water outlet channel 64 of the water cooling mechanism are arranged up and down along the radial section.

[0050] The water inlet circuit 63 includes a water inlet joint 631 disposed at one end of the motor shaft 3 and a water inlet channel 632 opened on the motor shaft 3, and the water outlet circuit 64 includes a water outlet joint 641 disposed at one end of the motor shaft 3 and a water outlet channel 642 opened on the motor shaft 3. The water inlet channel 632 and the water outlet channel 642 are respectively Y-shaped structures to facilitate the connection of the first water cooling branch 61 and the second water cooling branch 62.

[0051] The third branch section 521 of the middle oil cooling branch 52 extends from the motor shaft 3 to the water jacket 6 and passes through the gap of the S-shaped water channel of the water jacket 6. The fourth branch section 522 of the middle oil cooling branch 52 is formed by an annular groove 60 arranged around the outer wall of the water jacket 6. The structure of the water jacket 6 is fully utilized to arrange the third branch section 521 and the fourth branch section 522, so that the overall structural layout is more reasonable and the oil circuit and the water circuit are not connected to each other.

[0052] The thermal management working process of the present invention includes oil circuit circulation and water circuit circulation. The processes of oil circuit circulation and water circuit circulation are described below respectively: Oil circuit: see Figure 2 , Figure 3 and Figure 7As shown, the oil supply pump pumps cooling oil into the oil inlet through the oil inlet connector 530. After the cooling oil enters, it is transported upward through three oil cooling branches. The cooling oil passes through the first branch section 511 and the second branch section 512 of the two end oil cooling branches 51, and then is sprayed out from the oil injection port 501 of the second branch section 512 to spray cool the end of the armature winding 22; the cooling oil also passes through the third branch section 521, the fourth branch section 522 and the fifth branch section 523 of the middle oil cooling branch 52 and flows along the circumferential and axial directions of the stator core 21 on the inner side of the stator core 21, spray cooling the stator core 21 and the inner side of the middle of the armature winding 22. The cooling oil gathers in the oil collecting chamber 55 under the action of gravity. The oil level is higher than the oil inlet at the bottom of the oil extraction pipe 542. The oil extraction pump works to extract oil through the oil inlet at the bottom of the oil extraction pipe 542. With the oil extraction pressure, the cooling oil is extracted from the oil collecting chamber 55, enters the oil pump and then flows back to the oil tank, completing the oil circuit circulation.

[0053] Water circulation: see Figures 8 to 10 As shown, the cooling water enters the water inlet channel 632 of the motor shaft 3 through the water inlet joint 631, and is divided into two to enter the first water cooling branch 61 and the second water cooling branch 62 respectively. The cooling water flows along the water channel in an S shape to the bottom of the water jacket 6, and enters the water outlet channel 642 of the motor shaft 3 from the bottom. The cooling water is collected in the motor shaft 3 through the water outlet channel 642 and discharged to the water outlet joint 641, completing the water circuit circulation.

[0054] Although the present invention has been specifically shown and described in conjunction with the preferred embodiments, those skilled in the art should understand that the remaining undescribed portions are prior art, and that various changes made to the present invention in form and detail without departing from the spirit and scope of the present invention as defined in the appended claims shall fall within the scope of protection of the present invention.

Claims

1. A hub motor, characterized in that: It includes a rotor assembly, a stator assembly and an oil cooling mechanism, wherein the rotor assembly is used to be installed inside a wheel rim, the stator assembly is installed inside the rotor assembly, the stator assembly includes a stator core and an armature winding wound around the stator core, the stator core is installed outside a motor shaft, and the armature winding includes two end portions protruding from the stator core along the axial direction of the stator core; the oil cooling mechanism includes at least two oil cooling branches distributed at intervals along the axial direction of the stator core, at least one of the oil cooling branches sprays cooling oil to one end of the armature winding through an oil spray port arranged in the oil cooling branch, and at least one of the oil cooling branches supplies cooling oil to the stator core to cool the stator core.

2. The hub motor according to claim 1, characterized in that: The oil cooling branch includes two end oil cooling branches and a middle oil cooling branch. Along the axial direction of the stator core, the middle oil cooling branch is arranged between the two end oil cooling branches. The two end oil cooling branches are respectively used to spray cooling oil to one end of the armature winding, and the middle oil cooling branch is used to supply cooling oil to the stator core.

3. A hub motor according to claim 2, characterized in that: The oil cooling mechanism includes an oil inlet circuit arranged on the motor shaft, each of the oil cooling branches is respectively connected to the oil inlet circuit, the end oil cooling branch includes a first branch section connected to the oil inlet circuit and extending radially along the motor shaft, and a second branch section arranged radially outside the motor shaft, the oil spray port is arranged in the second branch section, and the second branch section is arranged along the axial direction of the motor shaft on the outside of the end of the armature winding, so that the oil spray port of the second branch section sprays cooling oil to one end of the armature winding.

4. The hub motor according to claim 3, characterized in that: The second branch section extends along the circumference of the motor shaft, and the second branch section is formed by an arc-shaped curved pipe extending along the circumference of the motor shaft. A plurality of the oil injection ports are provided, and the plurality of the oil injection ports are arranged along the extension direction of the arc-shaped curved pipe.

5. The hub motor according to claim 2, characterized in that: The oil cooling mechanism includes an oil inlet circuit arranged on the motor shaft, and the middle oil cooling branch includes a third branch section connected to the oil inlet circuit and a fourth branch section extending along the circumference of the stator core. The fourth branch section is arranged on the inner side of the stator core to cool the inner side of the stator core.

6. The hub motor according to claim 5, characterized in that: The middle oil-cooling branch also includes a fifth branch section extending along the axial direction of the stator core, the fifth branch section is formed by a plurality of grooves formed on the inner wall of the stator core, and the plurality of grooves are arranged at intervals along the circumference of the stator core and connected to the fourth branch section; the grooves penetrate the stator core axially along the stator core.

7. The hub motor according to claim 5, characterized in that: It also includes a water cooling mechanism, which includes a water jacket arranged between the motor shaft and the stator core, an S-shaped water channel is arranged inside the water jacket, the third branch section of the middle oil cooling branch is passed through the gap of the water channel, and the fourth branch section of the middle oil cooling branch is formed by an annular groove arranged around the outer wall of the water jacket.

8. The hub motor according to claim 2, characterized in that: The oil cooling mechanism includes an oil inlet circuit, an oil outlet circuit and an oil collecting chamber. The oil inlet circuit is arranged on the motor shaft, and the direction of gravity to which the hub motor is subjected when in use is defined as downward, and the opposite direction is defined as upward. The oil cooling branch extends upward from the oil inlet circuit, and the oil collecting chamber is arranged below the oil cooling branch circuit, so that the cooling oil flowing out of the oil cooling branch circuit is collected in the oil collecting chamber under the action of gravity and leaves the hub motor through the oil outlet circuit.

9. The hub motor according to claim 1, characterized in that: It also includes a water cooling mechanism, which includes a water jacket arranged between the motor shaft and the stator core.

10. The hub motor according to claim 9, characterized in that: An S-shaped water channel is provided inside the water jacket, and the water channel surrounds the outside of the motor shaft. The water channel is divided into a first water cooling branch and a second water cooling branch distributed on both sides of the radial section along a radial section of the motor shaft. The water inlet ends of the first water cooling branch and the second water cooling branch are connected to the same water inlet water channel, and the water outlet ends of the first water cooling branch and the second water cooling branch are connected to the same water outlet water channel.

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