Air-cooled motor and bridge driving system

Abstract

The invention provides an air cooling motor and a bridge driving system, the air cooling motor comprises a rotor shaft (1) and a motor rotor (2), the motor rotor (2) is installed on the rotor shaft (1), the rotor shaft (1) comprises a rotor shaft body (11), and the rotor shaft body (11) is a hollow shaft with a through hole in the axis; the rotor shaft (1) comprises a rotor shaft body (11) and blades, the blades are arranged in the rotor shaft body (11), the blades are configured to rotate along with the rotor shaft body (11), so that airflow flowing in the axial direction (A) of the rotor shaft is generated, and the airflow can cool the rotor shaft (1).

Description

Technical Field

[0001] The present application relates to an air-cooled motor rotor shaft, an air-cooled motor and an electric bridge drive system. Background Art

[0002] Patent CN111682677A discloses an integrated motor with a forced air cooling structure, which includes a fan, which is mounted on a controller heat dissipation housing and is surrounded by a fan cover. The outer surface of the motor housing is provided with a heat sink, the fan can promote the flow of air around the motor, and the heat sink can increase the heat dissipation area of ​​the housing, thereby achieving a better air cooling effect.

[0003] However, this structure can only promote the cooling of the outer surface of the motor, but has a poor cooling effect on the rotor shaft. The fan and the fan cover increase the axial length of the motor, which is not conducive to controlling the axial size of the motor. The fan has a complex structure and a large number of parts, resulting in high cost and low reliability.

[0004] Patent CN113824231A discloses a semi-enclosed forced air-cooled motor, in which the motor rotor and the housing are provided with air passages. When the rotor rotates, external air can enter the motor through the air passages to cool the motor.

[0005] However, the air passages on the motor rotor and housing make it difficult to control the radial size of the motor, and the motor rotor and housing have complex structures, which increases the cost. The air passage is connected to the outside air. Although the complex air passage and sealing design can reduce the entry of foreign matter into the motor, it is still impossible to completely prevent foreign matter from entering the motor or blocking the air passage, which can easily lead to motor failure. Summary of the invention

[0006] The present application aims to provide an air-cooled motor, which can avoid or reduce the problems existing in the above-mentioned air-cooled motors. The present application also provides an electric bridge drive system.

[0007] The embodiment of the present application provides an air-cooled motor, comprising a rotor shaft and a motor rotor, wherein the motor rotor is mounted on the rotor shaft, and the rotor shaft comprises:

[0008] A rotor shaft body, wherein the rotor shaft body is a hollow shaft with a through hole at the center; and

[0009] The blades are arranged inside the rotor shaft body and are configured to rotate together with the rotor shaft body, thereby generating an airflow flowing along the axial direction of the rotor shaft, and the airflow can cool the rotor shaft.

[0010] In at least one possible implementation, the rotor shaft further includes an air tube, an air passage is formed inside the air tube, the air tube is disposed inside the rotor shaft body, and the blades are connected to the air tube.

[0011] In at least one possible embodiment, the blade is an inclined wall, the inclined wall is inclined relative to the axial cross section of the air pipe, and the inclined wall divides the air channel into a first air channel and a second air channel.

[0012] The opening of the first air channel at one axial end of the rotor shaft is larger than the opening of the first air channel at the other axial end of the rotor shaft, and the opening of the second air channel at one axial end of the rotor shaft is smaller than the opening of the second air channel at the other axial end of the rotor shaft.

[0013] In at least one possible implementation, the air pipe includes a first air half pipe and a second air half pipe, wherein the first air half pipe and the second air half pipe are both semicircular pipes.

[0014] The first air half-tube includes a first inclined wall, and the second air half-tube includes a second inclined wall. The edges of the first inclined wall and the second inclined wall are tightly matched to form the inclined wall.

[0015] In at least one possible implementation manner, the air pipe and the rotor shaft body are clamped and fixed in the circumferential direction and the axial direction of the rotor shaft.

[0016] In at least one possible implementation manner, a peripheral wall of the air pipe is provided with a plurality of through holes, and air flow can contact the rotor shaft body through the through holes, thereby taking away heat from the rotor shaft body.

[0017] In at least one possible implementation manner, a plurality of reinforcing ribs are disposed on an outer circumferential surface of the air pipe, and the plurality of reinforcing ribs define a gap between the outer circumferential surface of the air pipe and an inner circumferential surface of the rotor shaft body.

[0018] In at least one possible implementation, the air pipe is made of plastic, the reinforcing ribs are in a circular ring shape, a plurality of the reinforcing ribs are spaced apart in the axial direction of the air pipe, and a plurality of through holes are provided between adjacent reinforcing ribs.

[0019] In at least one possible embodiment, the invention further includes a shell, wherein the shell is provided with a plurality of air holes, wherein the plurality of air holes are aligned with the rotor shaft at both axial ends of the rotor shaft, the aperture of the air holes is smaller than the aperture of the central hole of the rotor shaft body, and the radial gap between the rotor shaft and the shell is sealed by a seal.

[0020] The embodiment of the present application further proposes an electric bridge driving system, comprising:

[0021] The air-cooled motor according to any one of the above technical solutions; and

[0022] A gearbox, wherein an output shaft of the gearbox is offset relative to the rotor shaft.

[0023] By adopting the above technical solution, the present application can obtain at least one of the following beneficial effects.

[0024] (1) Air flows through the inside of the rotor shaft, and the rotor shaft is in direct contact with the air to dissipate heat, which can achieve better cooling effects on the rotor shaft and the motor rotor.

[0025] (2) The air passage is located in the hollow rotor shaft, which fully utilizes the internal space of the air-cooled motor or the electric bridge drive system, thereby reducing the overall size of the air-cooled motor or the electric bridge drive system.

[0026] (3) Foreign matter will not enter the motor through the air passage, thus ensuring the electrical safety of the motor.

[0027] (4) The air pipe has a simple structure, is easy to process and install, and has a low cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 A schematic structural diagram of an electric bridge drive system according to an embodiment of the present application is shown.

[0029] Figure 2 A schematic structural diagram of a rotor shaft body of an electric bridge drive system according to an embodiment of the present application is shown.

[0030] Figure 3 A schematic structural diagram of an air duct of an electric bridge drive system according to an embodiment of the present application is shown.

[0031] Figure 4 A schematic structural diagram of a first air half-pipe of an electric bridge drive system according to an embodiment of the present application is shown.

[0032] Figure 5 A schematic structural diagram of a second air half-pipe of an electric bridge drive system according to an embodiment of the present application is shown.

[0033] Figure 6 A schematic structural diagram of a motor housing and a motor end cover of an electric bridge drive system according to an embodiment of the present application is shown.

[0034] Figure 7 A schematic structural diagram of a motor end cover of an electric bridge drive system according to an embodiment of the present application is shown.

[0035] Figure 8A schematic structural diagram of a motor housing and a gearbox housing of an electric bridge drive system according to an embodiment of the present application is shown.

[0036] Fig. 9 A schematic structural diagram of a gearbox housing of an electric bridge drive system according to an embodiment of the present application is shown.

[0037] Description of Reference Numerals

[0038] 100 air-cooled motor 200 gearbox

[0039] P air channel P1 first air channel P2 second air channel

[0040] 1 Rotor shaft

[0041] 11 rotor shaft body 111 axial fixing slot 112 circumferential fixing slot

[0042] 12 air pipe 121 inclined wall 122 axial fixing buckle 123 circumferential fixing buckle 124 reinforcing rib 125 through hole

[0043] 12A first air half pipe 12B second air half pipe

[0044] 2 Motor rotor

[0045] 3 Motor stator

[0046] 4 housing 41 motor housing 42 motor end cover 421 motor end cover air hole 43 gearbox housing 431 gearbox housing air hole

[0047] 5 Motor end seal

[0048] 6 Transmission end seal

[0049] A-axis DETAILED DESCRIPTION

[0050] In order to more clearly explain the above-mentioned purposes, features and advantages of the present application, the specific implementation methods of the present application are described in detail in this section in conjunction with the accompanying drawings. In addition to the various implementation methods described in this section, the present application can also be implemented in other different ways. Without violating the spirit of the present application, those skilled in the art can make corresponding improvements, deformations and substitutions, so the present application is not limited by the specific embodiments disclosed in this section. The scope of protection of the present application shall be subject to the claims.

[0051] like Figures 1 to 9As shown, the embodiment of the present application proposes an electric bridge drive system, which can be used in, for example, electric vehicles. In one example, the front axle of the vehicle can use an oil-cooled electric bridge drive system, but considering the vehicle layout and cost, the rear axle of the vehicle does not have a water or oil pipeline connected to the electric bridge drive system for cooling. The electric bridge drive system can use air cooling, occupies a small space, and can be set on the rear axle of the vehicle.

[0052] The electric bridge drive system may include an air-cooled motor 100 and a gearbox 200. The air-cooled motor includes a rotor shaft 1, a motor rotor 2, a motor stator 3 and a housing 4. The rotor shaft 1, the motor rotor 2 and the motor stator 3 are arranged inside the housing 4. The motor rotor 2 is mounted on the rotor shaft 1, and the motor stator 3 is located radially outside the motor rotor 2. The air-cooled motor and the gearbox can be connected through the rotor shaft 1, some gears of the gearbox can be sleeved on the rotor shaft 1, and the air-cooled motor and the gearbox can be arranged inside the housing 4. The air-cooled motor can be an asynchronous motor. Here, the air-cooled motor may not include a speed change mechanism.

[0053] The axial direction A of the electric bridge drive system, the axial direction of the air-cooled motor, and the axial direction of the rotor shaft 1 are consistent. In the following description, unless otherwise specified, the axial direction A refers to the axial direction of the rotor shaft 1 .

[0054] like Figure 1 As shown, the housing 4 includes a motor housing 41, a motor end cover 42 and a gearbox housing 43. The motor housing 41 is used to accommodate the motor rotor 2, the motor stator 3, etc., and the gearbox housing 43 is used to accommodate the gears of the gearbox, etc. The motor end cover 42 and the gearbox housing 43 can be connected to the axial ends of the motor housing 41 respectively, and the rotor shaft 1 can be installed on the motor housing 41 and the gearbox housing 43 through bearings.

[0055] The rotor shaft 1 includes a rotor shaft body 11 and an air tube 12. The rotor shaft body 11 is a hollow shaft with a through hole at its axis. The air tube 12 is arranged inside the rotor shaft body 11. The air tube 12 and the rotor shaft body 11 are torsionally connected, and the air tube 12 can rotate together with the rotor shaft body 11.

[0056] like Figure 6 and Figure 7 As shown, the motor end cover 42 is provided with a plurality of motor end cover air holes 421, and the plurality of motor end cover air holes 421 are aligned with the rotor shaft 1. Figure 8 and Fig. 9 As shown, the gearbox housing 43 is provided with a plurality of gearbox housing air holes 431, and the plurality of gearbox housing air holes 431 are aligned with the rotor shaft 1. The gearbox housing air holes 431 and the motor end cover air holes 421 are respectively located at the axial ends of the rotor shaft 1. The apertures of the motor end cover air holes 421 and the gearbox housing air holes 431 are smaller than the aperture of the center hole of the rotor shaft body 11, which can prevent larger foreign matter from entering the interior of the rotor shaft 1.

[0057] It can be understood that the output shaft of the gearbox 200 can be offset relative to the rotor shaft 1, that is, the output shaft of the gearbox 200 can be arranged parallel to the rotor shaft of the motor but not coaxially (coaxially). Of course, the present application is not limited thereto.

[0058] The radial gap between the rotor shaft 1 and the housing 4 can be sealed by a seal, which can prevent small foreign matter inside the rotor shaft 1 from entering the motor or the gearbox. The seal may include a motor end seal 5 and a gearbox end seal 6, for example, Figure 1 The radial gap between the rotor shaft 1 and the motor end cover 42 may be provided with a motor end seal 5, which is sleeved on the rotor shaft 1. The radial gap between the rotor shaft 1 and the gearbox housing 43 may be provided with a gearbox end seal 6, which is sleeved on the rotor shaft 1.

[0059] like Figures 1 to 5 As shown, the inner circumferential surface of the rotor shaft body 11 may be provided with an axial fixing groove 111 and a circumferential fixing groove 112 .

[0060] The axial fixing groove 111 can cooperate with the axial fixing buckle 122 of the air tube 12, so that the rotor shaft body 11 and the air tube 12 are clamped and fixed in the axial direction A. The axial fixing groove 111 can be annular.

[0061] The circumferential fixing slot 112 can cooperate with the circumferential fixing buckle 123 of the air pipe 12, so that the rotor shaft body 11 and the air pipe 12 are circumferentially clamped and fixed, so that the air pipe 12 and the rotor shaft body 11 are torsionally connected. The circumferential fixing slot 112 can be tooth-shaped.

[0062] like Figures 3 to 5 As shown, the air pipe 12 is provided with an axial fixing buckle 122 and a circumferential fixing buckle 123 , and the axial fixing buckle 122 and the circumferential fixing buckle 123 can be respectively provided at two axial ends of the air pipe 12 .

[0063] The axial fixing buckle 122 can be an elastic claw. After the air tube 12 is inserted into the rotor shaft body 11, the elastic claw can be embedded in the axial fixing groove 111, so that the rotor shaft body 11 and the air tube 12 are clamped and fixed in the axial direction A.

[0064] The circumferential fixing buckle 123 may be tooth-shaped. After the air tube 12 is inserted into the rotor shaft body 11 , the circumferential fixing buckle 123 may be embedded in the circumferential fixing groove 112 , so that the air tube 12 and the rotor shaft body 11 are connected in a torsion-proof manner.

[0065] The air pipe 12 forms an air passage P inside. The rotor shaft body 11 may be provided with blades inside, and the blades may be connected to the air pipe 12. When the rotor shaft 1 rotates, the blades rotate together to generate an airflow flowing along the axial direction A of the rotor shaft 1 in the air passage P, thereby helping to cool the rotor shaft 1.

[0066] In a possible implementation, the blade may be an inclined wall 121, which is disposed in the air passage P inside the air pipe 12, and is inclined relative to the axial section of the air pipe 12. The inclined wall 121 may separate the air passage P into a first air passage P1 and a second air passage P2, and two openings with different areas are formed at both ends of the air pipe 12. When the rotor shaft 1 rotates, under the action of the inclined wall 121, the airflow may flow from the end with a larger opening area to the end with a smaller opening area.

[0067] The first air passage P1 is at one axial end ( Figure 1 The opening of the first air passage P1 at the left end is larger than that of the first air passage P1 at the other axial end ( Figure 1 The right end of the opening, refer to Figure 1 , the gas in the first air channel P1 flows from the left to the right. The second air channel P2 is at one axial end ( Figure 1 The opening of the second air passage P2 at the other axial end ( Figure 1 The right end of the opening, refer to Figure 1 , the gas in the second air passage P2 flows from the right side to the left side. The air can flow into or out of the housing 4 through the air holes on the housing 4, thereby cooling the rotor shaft 1 and the motor rotor 2 through the air flow.

[0068] like Figures 3 to 5 As shown, the air pipe 12 may include a first air half pipe 12A and a second air half pipe 12B. The first air half pipe 12A and the second air half pipe 12B may be semicircular pipes. The first air half pipe 12A and the second air half pipe 12B are installed opposite to each other.

[0069] like Figure 4 As shown, the first air half pipe 12A includes a first peripheral wall and a first inclined wall, and the first peripheral wall and the first inclined wall can be integrally formed. Figure 5 As shown, the second air half pipe 12B includes a second peripheral wall and a second inclined wall, and the second peripheral wall and the second inclined wall can be integrally formed. The edges of the first inclined wall and the second inclined wall are tightly matched to form an inclined wall 121, and the air pipe 12 is formed by splicing the first air half pipe 12A and the second air half pipe 12B, so that the air pipe 12 is easy to process and install, and the cost is low. The first inclined wall and the second inclined wall can both be flat plate structures, so the inclined wall 121 can also be a flat plate structure, and the inclined wall 121 can be inclined relative to the axial direction of the air pipe 12.

[0070] like Figure 1 and Figure 3 As shown, in the axial direction A of the electric bridge drive system, the air pipe 12 is located radially inside the motor rotor 2. The peripheral wall of the air pipe 12 is provided with a plurality of through holes 125, through which the air flow can contact the rotor shaft body 11, thereby taking away the heat of the rotor shaft body 11, and bringing the heat to the outside of the motor as the air flows in the air channel P.

[0071] The circumferential surface of the air pipe 12 may be provided with reinforcing ribs 124, which may be annular. For example, the outer circumferential surface of the air pipe 12 may be provided with a plurality of reinforcing ribs 124, which may be arranged at intervals along the axial direction A of the air pipe 12. The reinforcing ribs 124 may enhance the supporting rigidity of the air pipe 12 and prevent the air pipe 12 from deforming during operation. The reinforcing ribs 124 provided on the outer circumferential surface of the air pipe 12 define gaps between the outer circumferential surface of the air pipe 12 and the inner circumferential surface of the rotor shaft body 11, so that air can flow through these gaps, which is conducive to heat dissipation through airflow.

[0072] There may be a plurality of through holes 125 between adjacent reinforcing ribs 124, so that airflow can enter and exit through the through holes 125 to take away heat. The air pipe 12 and the rotor shaft body 11 can transfer heat through airflow without requiring large-area contact heat transfer, so that there is no need to perform large-area machining on the inner surface of the rotor shaft body 11. The air pipe 12 may be made of plastic, so that the air pipe 12 is light in weight and low in cost. Of course, the air pipe may be made of metal.

[0073] The electric bridge drive system of the above embodiment has at least one of the following advantageous effects.

[0074] (1) Air flows through the inside of the rotor shaft. The rotor shaft of the motor rotor with a large heat generation is in direct contact with the air to dissipate heat, which can achieve better cooling effect on the rotor shaft and the motor rotor.

[0075] (2) The air passage is located in the hollow rotor shaft, making full use of the internal space of the air-cooled motor or the electric bridge drive system, making the overall size of the air-cooled motor or the electric bridge drive system smaller and facilitating the layout of the vehicle space.

[0076] (3) Foreign matter will not enter the motor through the air passage, especially the space between the rotor shaft and the housing 4, and will not affect the rotor, coil, etc. of the motor, thus ensuring the electrical safety of the motor. Of course, foreign matter will not enter the gearbox 200, and will not affect the operation of the gears.

[0077] (4) The air pipe has a simple structure, is easy to process and install, and has a low cost.

[0078] The present application is not limited to the above embodiments, and those skilled in the art can make various modifications to the above embodiments of the present application under the guidance of the present application without departing from the scope of the present application. In addition, the following description is also made.

[0079] (1) The reinforcing ribs 124 are not limited to being provided on the outer peripheral surface of the air tube 12, but may be provided on the inner peripheral surface of the air tube.

[0080] (2) The blades are not limited to inclined walls. The blades can generate axial airflow when rotating. The airflow generated by the blades can also flow unidirectionally along the axial direction.

[0081] (3) The air pipe 12 is not limited to being formed by combining two half pipes, but may also be connected or integrally formed in other ways. For example, the pipe body (or pipe wall portion) of the air pipe 12 may be formed separately from the blades or the inclined wall and then assembled together.

[0082] (4) The concepts, structures or features of the embodiments of the present application can also be applied to air-cooled motors, especially air-cooled motors including a speed change mechanism. The output shaft of the speed change mechanism can be offset relative to the rotor shaft of the motor, that is, the output shaft of the speed change mechanism can be arranged parallel to the rotor shaft of the motor but not coaxially (coaxially). Of course, the present application is not limited to this.

[0083] (5) It can be understood that in the electric bridge drive system of the present application, the motor and the gearbox can be separated by a structure such as a partition wall, and the gearbox can be cooled by a coolant such as oil.

[0084] (6) In the electric axle drive system of the present application, the air duct and the blades or inclined walls can be mainly arranged in the motor housing without extending to the gearbox.

[0085] The diameter of the portion of the motor shaft located in the gearbox may be smaller than the diameter of the portion of the motor shaft located in the motor housing as a whole. Thus, the diameter of the portion of the motor shaft located in the gearbox may be smaller, which is beneficial to miniaturization.

[0086] It should be understood that at least some aspects or features of the above-mentioned implementation modes, embodiments or examples may be appropriately combined.

[0087] It is understood that in the present application, when the number of parts or components is not particularly limited, the number may be one or more, and the multiple here means two or more. For the case where the number of parts or components shown in the drawings and / or described in the specification is a specific number such as two, three, four, etc., the specific number is usually exemplary and not restrictive, and it can be understood as multiple, that is, two or more, but this does not mean that the present application excludes the case of one.

[0088] In the present application, unless otherwise clearly stated or limited, the terms such as "install", "assemble", "assemble", "connect", "connect", "couple", "link", "abut", "connect", "interconnect", "intercommunication", "conduction", "fixation", "fastening" and the like should be understood in a broad sense, for example, they can be direct or indirect. For example, regarding connection, it can be a fixed connection, a detachable connection, or an integral one; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly stated or limited. For example, regarding connectivity / conduction, it can be direct connectivity / conduction, or it can be indirect connectivity / conduction via an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to the specific circumstances.

[0089] In the present application, unless otherwise clearly stated or limited, a component disposed on / installed on / located on / accommodated on / placed in, within, inside, etc. another component may be any of the following two situations: a part or most of the one component is located in the other component; and the one component is completely accommodated in the other component.

[0090] Although the present application is described in detail using the above-mentioned embodiments, it is obvious to those skilled in the art that the present application is not limited to the embodiments described in this specification. The present application can be modified and implemented as a modified embodiment without departing from the subject matter and scope of the present application as determined by the claims. Therefore, the description in this specification is for the purpose of illustration and does not have any restrictive meaning for the present application.

Claims

1. An air-cooled motor, comprising a rotor shaft (1) and a motor rotor (2), wherein the motor rotor (2) is mounted on the rotor shaft (1), characterized in that: The rotor shaft (1) comprises: A rotor shaft body (11), wherein the rotor shaft body (11) is a hollow shaft with a through hole at its axis; and The blades are arranged inside the rotor shaft body (11), and the blades are configured to rotate together with the rotor shaft body (11), thereby generating an airflow flowing along the axial direction (A) of the rotor shaft, and the airflow can cool the rotor shaft (1).

2. The air-cooled motor according to claim 1, characterized in that: The rotor shaft further comprises an air pipe (12), an air passage (P) is formed inside the air pipe (12), the air pipe (12) is arranged inside the rotor shaft body (11), and the blades are connected to the air pipe (12).

3. The air-cooled motor according to claim 2, characterized in that: The blade is an inclined wall (121), the inclined wall (121) is inclined relative to the axial section of the air pipe (12), and the inclined wall (121) divides the air passage (P) into a first air passage (P1) and a second air passage (P2). An opening of the first air channel (P1) at one axial end of the rotor shaft is larger than an opening of the first air channel (P1) at the other axial end of the rotor shaft, and an opening of the second air channel (P2) at one axial end of the rotor shaft is smaller than an opening of the second air channel (P2) at the other axial end of the rotor shaft.

4. The air-cooled motor according to claim 3, characterized in that: The air pipe (12) comprises a first air half pipe (12A) and a second air half pipe (12B), wherein the first air half pipe (12A) and the second air half pipe (12B) are both semicircular pipes. The first air half-tube (12A) comprises a first inclined wall, and the second air half-tube (12B) comprises a second inclined wall, and the edges of the first inclined wall and the second inclined wall are tightly matched to form the inclined wall (121).

5. The air-cooled motor according to claim 2, characterized in that: The air pipe (12) and the rotor shaft body (11) are clamped and fixed in the circumferential direction and axial direction (A) of the rotor shaft.

6. The air-cooled motor according to claim 2, characterized in that: The peripheral wall of the air pipe (12) is provided with a plurality of through holes (125), and the air flow can contact the rotor shaft body through the through holes (125), thereby taking away the heat of the rotor shaft body.

7. The air-cooled motor according to claim 2, characterized in that: The outer circumferential surface of the air pipe (12) is provided with a plurality of reinforcing ribs (124), and the plurality of reinforcing ribs (124) define a gap between the outer circumferential surface of the air pipe (12) and the inner circumferential surface of the rotor shaft body.

8. The air-cooled motor according to claim 7, characterized in that: The air pipe (12) is made of plastic, the reinforcing ribs (124) are annular, a plurality of the reinforcing ribs (124) are arranged at intervals in the axial direction of the air pipe (12), and a plurality of through holes (125) are provided between adjacent reinforcing ribs (124).

9. The air-cooled motor according to claim 1, characterized in that: It also comprises a shell (4), the shell (4) being provided with a plurality of air holes, the plurality of air holes being aligned with the rotor shaft (1) at both axial ends of the rotor shaft (1), the apertures of the air holes being smaller than the aperture of the central hole of the rotor shaft body (11), and the radial gap between the rotor shaft (1) and the shell (4) being sealed by a sealing member.

10. An electric bridge drive system, characterized in that: include: The air-cooled motor according to any one of claims 1 to 9; as well as A gearbox, wherein the output shaft of the gearbox is offset relative to the rotor shaft (1).

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