Driving motor and its rotating shaft structure

Abstract

The application discloses a motor rotating shaft structure, characterized in that the motor rotating shaft structure comprises a rotor shaft cylinder, the rotor shaft cylinder is provided with a first through cavity penetrating along the axial direction, the rotor shaft cylinder is arranged outside an inner cylinder, an end of the rotor shaft cylinder away from the inner cylinder is provided with a rotor connecting flange, and a rotor iron core is connected to the outer surface of the rotor shaft cylinder; the inner cylinder is provided with a second through cavity penetrating along the axial direction; a first bearing and a second bearing are arranged between the inner cylinder and the rotor shaft cylinder, and the first bearing and the second bearing are arranged in the axial projection range of the rotor iron core. The motor rotating shaft structure shortens the overall axial length of the motor rotating shaft, thereby reducing the length of the radial magnetic flux motor in the axial direction and making the motor more compact. The application further discloses a driving motor.

Description

Technical Field

[0001] This invention relates to the field of drive motor technology, and in particular to a drive motor and its shaft structure. Background Technology

[0002] Existing new energy vehicles typically use permanent magnet synchronous motors (PMSMs) as their power source for their electric axles or electric drive assemblies. While using an axial flux motor could significantly reduce the axial dimension of the PMSM, it would also greatly increase the diameter, posing challenges for layout and installation, and increasing costs. Therefore, in current technology, most PMSMs utilize radial flux motors.

[0003] Existing radial flux motors, such as Figure 1 As shown, it includes a motor shaft 03, a rotor 02, and a stator 04. The two ends of the motor shaft 03 are supported by a first bearing 01 and a second bearing 05. The motor shaft 03 is a solid shaft. Radial flux motors have a relatively long axial length, resulting in poor structural compactness. They require a large axial length space when installed on a vehicle, causing inconvenience in installation and use, and limiting their application in installation scenarios. Summary of the Invention

[0004] In view of this, the present invention provides a motor shaft structure that shortens the overall axial length of the motor shaft, thereby reducing the length of the radial flux motor in the axial direction and making the motor structure more compact.

[0005] The present invention also provides a drive motor.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] A motor shaft structure includes a rotor shaft sleeve, the rotor shaft sleeve having a first through cavity extending along the axial direction, the rotor shaft sleeve being sleeved on the outside of an inner cylinder, a rotor connecting flange being provided at the end of the rotor shaft sleeve away from the inner cylinder, and a rotor core being connected to the outer surface of the rotor shaft sleeve; the inner cylinder having a second through cavity extending along the axial direction.

[0008] A first bearing and a second bearing are provided between the inner cylinder and the rotor shaft cylinder, and the first bearing and the second bearing are located within the axial projection range of the rotor core.

[0009] Optionally, the inner rings of the first bearing and the second bearing are configured for transition fit with the outer surface of the inner cylinder, and the outer rings of the first bearing and the second bearing are configured for interference fit with the inner surface of the rotor shaft cylinder.

[0010] Optionally, a bearing spacer sleeve for limiting the inner rings of the first bearing and the second bearing is provided on the inner cylinder, and the bearing spacer sleeve is disposed between the first bearing and the second bearing.

[0011] The bearing spacer includes a main sleeve body fitted onto the inner cylinder, one end face of the main sleeve body contacting the inner ring end face of the first bearing, and the other end face contacting the inner ring end face of the second bearing.

[0012] The outer surface of the main sleeve is provided with a circumferentially arranged protruding ring, and the outer surface of the protruding ring is spaced apart from the inner surface of the corresponding position of the first through cavity by a set distance.

[0013] The set distance is 0.4 to 0.8 mm.

[0014] Optionally, the convex ring is provided with a plurality of evenly distributed weight-reducing grooves;

[0015] The weight-reducing groove is arranged circumferentially around the outer surface of the convex ring, or the weight-reducing groove is arranged parallel to the axial direction of the convex ring;

[0016] The width of the convex ring at the end closer to the main sleeve is smaller than the width at the end farther from the main sleeve.

[0017] Optionally, the inner cylinder includes a bearing support cylinder, a connecting cylinder, and an end cylinder integrally arranged in sequence, wherein the bearing support cylinder, the connecting cylinder, and the end cylinder are arranged in a stepped manner;

[0018] The first bearing and the second bearing are sleeved on the bearing support cylinder, the end cylinder is used to connect with the rear end cover of the motor, and the outer surfaces of the connecting cylinder and the end cylinder are provided with oil guide grooves.

[0019] Optionally, the rotor shaft includes a cylinder and a first end connecting flange, the first end connecting flange being used to connect to the rotor connecting flange;

[0020] A flange stop is provided on the end face of the first end connecting flange near the rotor connecting flange, and the end of the rotor connecting flange near the first end connecting flange is fitted onto the flange stop.

[0021] The first end connecting flange is provided with a first connecting through hole for connecting with the rotor connecting flange.

[0022] Optionally, the rotor connecting flange includes a second end connecting flange, a resolver mounting ring, an oil seal ring, and a flange key arranged sequentially. The second end connecting flange, resolver mounting ring, oil seal ring, and flange key are an integral structure. The second end connecting flange is used to connect with the first end connecting flange. The resolver mounting ring is used to install the rotor of the resolver. The oil seal ring is used to cooperate with the oil seal on the front end cover of the motor to achieve sealing.

[0023] The rotor connecting flange is provided with a third through cavity along the axial direction.

[0024] The first cavity, the second cavity, and the third cavity are connected.

[0025] Optionally, the disc surface of the second end connecting flange is an arc-shaped surface convex to the resolver mounting ring platform, and the edge of the second end connecting flange is provided with a plurality of connecting platforms, which are evenly distributed at the edge position of the second end connecting flange. Each connecting platform is provided with a second connecting through hole, and the first connecting through hole and the second connecting through hole are correspondingly provided.

[0026] Optionally, the rotor shaft and the rotor connecting flange are connected or welded together by a connector, or the rotor shaft and the rotor connecting flange are an integral structure.

[0027] As can be seen from the above technical solution, the present invention provides a method for supporting the motor shaft by using a hollow rotor shaft cylinder in conjunction with an inner cylinder. The first and second bearings are built into the gap between the inner cylinder and the rotor shaft cylinder. Furthermore, the first and second bearings are located within the axial projection range of the rotor core, that is, the two supporting bearings are installed inside the axial space corresponding to the rotor core of the motor. This shortens the overall axial length of the motor shaft, thereby reducing the axial length of the radial flux motor, making the motor structure more compact, requiring less axial length space during vehicle installation, and facilitating installation and use.

[0028] The present invention also provides a drive motor, including a housing and a motor shaft, rotor and stator assembly disposed inside the housing. One end of the housing is provided with a rear end cover and the other end is provided with a front end cover. The motor shaft is the motor shaft structure described above.

[0029] The drive motor of the present invention has the motor shaft structure described above, and therefore has the advantages of the motor shaft structure described above, which will not be repeated here. Attached Figure Description

[0030] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0031] Figure 1 This is a cross-sectional view of a radial flux motor in the prior art.

[0032] Figure 2 This is a cross-sectional view of the drive motor provided in an embodiment of the present invention;

[0033] Figure 3 This is a cross-sectional view of the motor shaft structure provided in an embodiment of the present invention;

[0034] Figure 4 This is a schematic diagram of the structure of the bearing spacer sleeve provided in an embodiment of the present invention;

[0035] Figure 5 This is a cross-sectional view of the bearing spacer sleeve and bearing position provided in an embodiment of the present invention;

[0036] Figure 6 A schematic diagram of the connection structure of the inner cylinder, the rear end cover, and the outer shell provided in an embodiment of the present invention;

[0037] Figure 7 This is a schematic diagram of the rotor shaft cylinder provided in an embodiment of the present invention;

[0038] Figure 8 This is a schematic diagram of the rotor connection flange provided in an embodiment of the present invention;

[0039] Figure 9 This is a schematic diagram of the connection structure between the rotor connecting flange and the rotor shaft cylinder provided in an embodiment of the present invention;

[0040] Figure 10 for Figure 9 A cross-sectional structural diagram.

[0041] in:

[0042] 01. First bearing; 02. Rotor; 03. Motor shaft; 04. Stator; 05. Second bearing.

[0043] 1. Outer shell

[0044] 2. First bearing,

[0045] 3. Bearing spacer sleeve,

[0046] 301. Main sleeve body; 302. Mounting through hole; 303. Raised ring; 304. Weight reduction groove.

[0047] 4. Stator assembly,

[0048] 5. Rotor core,

[0049] 6. Second bearing,

[0050] 7. Fixing ring,

[0051] 8. Front cover,

[0052] 9. Oil seal,

[0053] 10. Rotor connection flange,

[0054] 1001. Flanged key; 1002. Second end connecting flange; 1003. Third through cavity; 1004. Oil seal ring; 1005. Resolver mounting ring; 1006. Connecting platform; 1007. Second connecting through hole.

[0055] 11. Inner cylinder,

[0056] 1101. Bearing support cylinder; 1102. Second through cavity; 1103. Limiting ring platform; 1104. Connecting cylinder; 1105. End cylinder; 1106. Oil guide groove.

[0057] 12. Rear end cover

[0058] 13. Rotor shaft and cylinder

[0059] 1301. Cylinder body; 1302. First end connecting flange; 1303. First through cavity; 1304. First connecting through hole; 1305. Flange stop.

[0060] 14. First baffle,

[0061] 15. Positioning pin,

[0062] 16. Second connecting bolt,

[0063] 17. Front sealing cover,

[0064] 18. Rear sealing cap,

[0065] 19. First connecting bolt,

[0066] 20. Connecting nuts,

[0067] 21. Reinforcing ribs,

[0068] 22. Second baffle. Detailed Implementation

[0069] This invention discloses a motor shaft structure that shortens the overall axial length of the motor shaft, thereby reducing the axial length of the radial flux motor and making the motor structure more compact.

[0070] The present invention also discloses a drive motor.

[0071] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0072] See Figures 2 to 10 The motor shaft structure of the present invention includes a rotor shaft sleeve 13, which is sleeved on the outside of an inner cylinder 11. The inner cylinder 11 has a second through cavity 1102 extending along the axial direction, and the rotor shaft sleeve 13 has a first through cavity 1303 extending along the axial direction. A rotor core 5 is connected to the outer surface of the rotor shaft sleeve 13. A first bearing 2 and a second bearing 6 are provided between the inner cylinder 11 and the rotor shaft sleeve 13. The first bearing 2 and the second bearing 6 are located within the axial projection range of the rotor core 5 and are used to support the rotating rotor shaft sleeve 13 and the rotor core 5. A rotor connecting flange 10 is provided at the end of the rotor shaft sleeve 13 away from the inner cylinder 11. The rotor connecting flange 10 is used to output the rotation of the motor and realize the function of transmitting power torque by the motor shaft.

[0073] To improve the stability of the bearing support, the first bearing 2 and the second bearing 6 are spaced a certain distance apart. The specific length of this "certain distance" can be set by those skilled in the art according to actual needs, and is not limited here. Both the second through cavity 1102 and the first through cavity 1303 are cylindrical through cavities.

[0074] The motor shaft structure of the present invention uses a hollow rotor shaft cylinder 13 in conjunction with an inner cylinder 11. The first bearing 2 and the second bearing 6, which support the motor shaft, are housed in the gap between the inner cylinder 11 and the rotor shaft cylinder 13. Furthermore, the first bearing 2 and the second bearing 6 are positioned within the axial projection range of the rotor core 5. In other words, the two supporting bearings are installed within the axial space corresponding to the rotor core 5 of the motor, which shortens the overall axial length of the motor shaft. This reduces the axial length of the radial flux motor, resulting in a more compact motor structure. The axial length space required for vehicle installation is smaller, making installation and use easier.

[0075] The inner rings of the first bearing 2 and the second bearing 6 are fitted with the outer surface of the inner cylinder 11 in a transition fit, facilitating the installation of the bearings on the inner cylinder 11. Simultaneously, the inner rings of the bearings remain fixed relative to the inner cylinder 11. The outer rings of the first bearing 2 and the second bearing 6 are fitted with the inner surface of the rotor shaft cylinder 13 in an interference fit, ensuring that the outer rings of both bearings are tightly connected to the rotor shaft cylinder 13 for rotation. In other words, the outer rings of the first bearing 2, the second bearing 6, and the rotor shaft cylinder 13 rotate relative to the inner cylinder 11.

[0076] To maintain the axial distance between the inner rings of the first bearing 2 and the second bearing 6, a bearing spacer sleeve 3 is fitted onto the inner cylinder 11 to limit the inner rings of the first bearing 2 and the second bearing 6. The bearing spacer sleeve 3 is positioned between the first bearing 2 and the second bearing 6. Specifically, the bearing spacer sleeve 3 includes a main sleeve body 301 fitted onto the inner cylinder 11. To facilitate installation on the inner cylinder 11, the main sleeve body 301 has an axially provided mounting through hole 302, such as... Figure 4 As shown, the inner cylinder 11 is inserted into the mounting through hole 302. One end face of the main sleeve 301 contacts the inner ring end face of the first bearing 2, and the other end face contacts the inner ring end face of the second bearing 6. The inner surface of the mounting through hole 302 and the surface of the inner cylinder 11 are transitionally fitted, which ensures the positional reliability of the bearing spacer sleeve 3 on the inner cylinder 11 and facilitates installation. When the motor is working, the bearing spacer sleeve 3 and the inner cylinder 11 remain stationary.

[0077] To ensure ease of installation, a circumferentially oriented convex ring 303 is provided on the outer surface of the main sleeve 301. The difference between the radius of the outer surface of the convex ring 303 and the radius of the corresponding position of the first through cavity 1303 is 0.4 to 0.8 mm, thereby ensuring a set distance between the outer surface of the convex ring 303 and the inner surface of the first through cavity 1303. A raised convex ring 303 is provided on the bearing spacer sleeve 3, and the radius of the outer surface of the convex ring 303 is limited. This ensures that before the bearing spacer sleeve 3 comes into contact with the inner cylinder 11, the outer surface of the convex ring 303 is supported by the inner wall of the first through cavity 1303, keeping the bearing spacer sleeve 3 close to the center of the rotating shaft and preventing it from deviating too much from the axis. This allows the inner cylinder 11 to smoothly pass through the inner holes of the first bearing 2, the bearing spacer sleeve 3, and the second bearing 6 during assembly. Meanwhile, the outer surface of the convex ring 303 and the inner surface of the first through cavity 1303 are spaced at a predetermined distance, i.e., there is a gap between the two surfaces that are close to each other. This avoids interference or friction between the inner wall of the first through cavity 1303 and the bearing spacer sleeve 3 when the rotor rotates, thus preventing damage caused by interference or friction. If the gap is too large, the bearing spacer sleeve 3 will lose its centering function, making it difficult to align and assemble; if the gap is too small, the rotor shaft cylinder 13 may rub against the outer surface of the convex ring 303 due to vibration and manufacturing eccentricity errors when rotating. In this embodiment, the predetermined distance is 0.4 to 0.8 mm.

[0078] To reduce the weight of the bearing spacer sleeve 3, a plurality of evenly distributed weight-reducing grooves 304 are provided on the convex ring 303. The weight-reducing grooves 304 are arranged circumferentially around the outer surface of the convex ring 303, or parallel to the axial direction of the convex ring 303. Preferably, the weight-reducing grooves 304 are arranged parallel to the axial direction of the convex ring 303, such as... Figure 4As shown, this facilitates the flow of lubricating oil between the two bearings. Furthermore, the width of the end of the convex ring 303 near the main sleeve 301 is smaller than the width of the end away from the main sleeve 301, as shown... Figure 5 As shown, the cross-section of the convex ring 303 is T-shaped.

[0079] In one embodiment, the inner cylinder 11 includes a bearing support cylinder 1101, a connecting cylinder 1104, and an end cylinder 1105 integrally arranged in sequence, such as... Figure 3 and Figure 6 As shown, the bearing support cylinder 1101, connecting cylinder 1104, and end cylinder 1105 are arranged in a stepped manner. The diameter of the bearing support cylinder 1101 is smaller than the diameter of the connecting cylinder 1104, and the diameter of the connecting cylinder 1104 is smaller than the diameter of the end cylinder 1105. Correspondingly, the second through cavity 1102 is a cavity that penetrates the inner cylinder 11, and the second through cavity 1102 is a stepped cavity so that the wall thickness of each section of the inner cylinder 11 is close to or the same. Among them, the first bearing 2 and the second bearing 6 are sleeved and installed on the bearing support cylinder 1101, and the end of the end cylinder 1105 is used to connect with the rear end cover 12 of the motor.

[0080] For oil-cooled motors, the bearings are generally open bearings, requiring oil to flow through the bearing locations for lubrication. To facilitate lubricant flow, the outer surfaces of the connecting cylinder 1104 and the end cylinder 1105 are provided with interconnected oil guide grooves 1106. These grooves guide the oil within the motor cavity to the two bearings, resulting in better lubrication. A limiting ring 1103 is provided on the bearing support cylinder 1101 near the connecting cylinder 1104. Figure 5 and Figure 6 As shown, one side of the inner ring of the first bearing 2 is axially limited by the limiting ring platform 1103, and the other end is axially limited by the bearing spacer sleeve 3. One side of the inner ring of the second bearing 6 is axially limited by the bearing spacer sleeve 3, and the other side is limited by the retaining ring 7. The retaining ring 7 is used to clamp the second bearing 6 and a series of parts to its left onto the inner cylinder 11, achieving axial limitation. In one embodiment, the retaining ring 7 is threaded onto the inner cylinder 11 for easy disassembly and maintenance. In other embodiments, the retaining ring 7 and the inner cylinder 11 can also be connected by welding, interference fit, or other connection methods commonly used in the art, depending on the actual situation.

[0081] For water-cooled or air-cooled motors, since there is no flowing oil to lubricate the bearings inside the motor, the two bearings of the motor are generally closed bearings. The closed bearings contain grease inside, which can form self-lubrication and do not require external oil for lubrication. Therefore, the inner cylinder 11 of the motor with closed bearings does not need to be equipped with an oil guide groove 1106.

[0082] In one embodiment, the rotor shaft cylinder 13 includes a cylinder body 1301 and a first end connecting flange 1302, such as Figure 7As shown, the first end connecting flange 1302 is used to connect with the rotor connecting flange 10. A flange stop 1305 is provided on the end face of the first end connecting flange 1302 near the rotor connecting flange 10, and the end of the rotor connecting flange 10 near the first end connecting flange 1302 is fitted onto the flange stop 1305. A first connecting through hole 1304 is provided on the first end connecting flange 1302 for connecting with the rotor connecting flange 10. The rotor connecting flange 10 is used to transmit the rotational power generated by the rotor core 5 of the motor. The flange stop 1305 on the rotor shaft cylinder 13 is used to position the rotor connecting flange 10. One end of the rotor core 5 is limited by a first baffle 14, and the other end is limited by a second baffle 22. The first baffle 14 is connected to the rotor shaft cylinder 13 by threads or other commonly used connection methods. The second baffle 22 is fitted onto the stepped surface at the end of the rotor shaft cylinder 13, and the second baffle 22 is pressed between the first end connecting flange 1302 and the rotor core 5. The rotor includes a rotor core 5, a rotor shaft cylinder 13, a first baffle 14, and a second baffle 22.

[0083] Accordingly, the rotor connecting flange 10 includes a second-end connecting flange 1002, a resolver mounting ring 1005, an oil seal ring 1004, and a flange key 1001 arranged sequentially. Specifically, the second-end connecting flange 1002, the resolver mounting ring 1005, the oil seal ring 1004, and the flange key 1001 are an integral structure, as shown below. Figure 8 As shown. The second end connecting flange 1002 is used to connect with the first end connecting flange 1302. The resolver mounting ring 1005 is used to install the rotor of the resolver. The oil seal ring 1004 is used to cooperate with the oil seal 9 on the front end cover 8 of the motor to achieve the sealing of the motor cavity. The flange key 1001 is used to connect with the external structure that transmits power torque, specifically it can be connected with a gear or a shaft. The rotor connecting flange 10 has a third through cavity 1003 through it along the axial direction, that is, the rotor connecting flange 10 is a hollow structure. The second through cavity 1102, the first through cavity 1303 and the third through cavity 1003 are connected, that is, the entire motor shaft is set as a hollow structure. On the one hand, it is easy to reduce weight, and on the other hand, it increases the degree of design freedom. The hollow structure inside can pass through shaft parts or install gear parts, which facilitates the expansion to realize more functions and structures and is suitable for more applications.

[0084] Furthermore, the disc surface of the second-end connecting flange 1002 is the arc-shaped surface of the convex revolute mounting ring 1005, such as... Figure 8As shown, the edge of the second-end connecting flange 1002 is provided with a plurality of connecting platforms 1006, which are evenly distributed at the edge of the second-end connecting flange 1002. Each connecting platform 1006 is provided with a second connecting through hole 1007, and the first connecting through hole 1304 is correspondingly provided with the second connecting through hole 1007. In one embodiment, the second-end connecting flange 1002 and the first-end connecting flange 1302 are connected by a first connecting bolt 19 and a connecting nut 20, as shown. Figure 9 and Figure 10 As shown, the tail end of the first connecting bolt 19 passes through the first connecting through hole 1304 and the second connecting through hole 1007 and is connected to the connecting nut 20. In other embodiments, a separate bolt can also be used for installation, or the rotor shaft cylinder 13 and the rotor connecting flange 10 can be connected together by welding, or the rotor shaft cylinder 13 and the rotor connecting flange 10 can be an integral structure, that is, a single part.

[0085] To seal the hollow structure of the motor shaft, a front sealing cover 17 is provided at the front end of the third cavity 1003 of the rotor connecting flange 10, and a rear sealing cover 18 is provided at the rear end of the second cavity 1102. By providing the front sealing cover 17 and the rear sealing cover 18, oil inside the cavity of the motor shaft structure of the oil-cooled motor is prevented from flowing out, and external debris or moisture is prevented from entering the cavity of the motor shaft structure.

[0086] The motor shaft structure of this invention utilizes an inner cylinder 11 to support the bearings, replacing the bearing holes of the front and rear end covers in the prior art that support the motor shafts extending from both ends. The supporting bearings are built into the central cavity of the shaft, which greatly reduces the axial length of the motor shaft. By setting the bearing spacer sleeve 3, both the bearing positioning function and the assembly and disassembly requirements of the manufacturing process are met. The rotor core 5 is combined with the rotor connecting flange 10 to realize the function of transmitting power torque by the motor shaft. The rotor shaft cylinder 13 and the rotor connecting flange 10 are separate parts with hollow interiors, allowing for the installation of more components, such as gears, drive shafts, or other bearings, resulting in a more compact structure and lighter weight, suitable for a wider range of applications.

[0087] This invention also provides a drive motor, including a housing 1 and a motor shaft, rotor, and stator assembly 4 disposed inside the housing 1. One end of the housing 1 is provided with a rear end cover 12, and the other end with a front end cover 8. The motor shaft has the aforementioned structure. The rear end cover 12 is welded to the inner cylinder 11 and the housing 1 or connected via a connector. When the rear end cover 12 is welded to the inner cylinder 11 and the housing 1, a reinforcing rib 21 is provided on the surface of the rear end cover 12 near the motor cavity to improve structural strength. The rear end cover 12 is used to cover and seal the rear part of the motor's inner cavity. The power output end of the motor rotor is provided with the front end cover 8. The front end cover 8 covers the front part of the motor's inner cavity and provides a mounting position for the oil seal 9. The front end cover 8 is connected to the housing 1 via a second connecting bolt 16 and a locating pin 15, facilitating the installation and disassembly of the internal components of the motor.

[0088] In the description of this solution, it should be understood that the terms "upper", "lower", "vertical", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship 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, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this solution.

[0089] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this solution, "multiple" means two or more, unless otherwise explicitly specified.

[0090] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0091] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A motor shaft structure, characterized in that, The device includes a rotor shaft cylinder, which has a first through cavity extending along the axial direction. The rotor shaft cylinder is sleeved on the outside of an inner cylinder. A rotor connecting flange is provided at the end of the rotor shaft cylinder away from the inner cylinder. A rotor core is connected to the outer surface of the rotor shaft cylinder. The inner cylinder has a second through cavity extending along the axial direction. A first bearing and a second bearing are provided between the inner cylinder and the rotor shaft cylinder, and the first bearing and the second bearing are located within the axial projection range of the rotor core. The inner cylinder is fitted with a bearing spacer sleeve for limiting the inner rings of the first bearing and the second bearing, and the bearing spacer sleeve is disposed between the first bearing and the second bearing. The bearing spacer includes a main sleeve body fitted onto the inner cylinder, one end face of the main sleeve body contacting the inner ring end face of the first bearing, and the other end face contacting the inner ring end face of the second bearing. The outer surface of the main sleeve is provided with a circumferentially arranged protruding ring, and the outer surface of the protruding ring is spaced at a certain distance from the inner surface of the corresponding position of the first through cavity.

2. The motor shaft structure according to claim 1, characterized in that, The inner rings of the first bearing and the second bearing are configured for transition fit with the outer surface of the inner cylinder, and the outer rings of the first bearing and the second bearing are configured for interference fit with the inner surface of the rotor shaft cylinder.

3. The motor shaft structure according to claim 1 or 2, characterized in that, The set distance is 0.4 to 0.8 mm.

4. The motor shaft structure according to claim 3, characterized in that, The convex ring is provided with several evenly distributed weight-reducing grooves; The weight-reducing groove is arranged circumferentially around the outer surface of the convex ring, or the weight-reducing groove is arranged parallel to the axial direction of the convex ring; The width of the convex ring at the end closer to the main sleeve is smaller than the width at the end farther from the main sleeve.

5. The motor shaft structure according to claim 1, characterized in that, The inner cylinder includes a bearing support cylinder, a connecting cylinder, and an end cylinder that are integrally arranged in sequence, and the bearing support cylinder, the connecting cylinder, and the end cylinder are arranged in a stepped manner. The first bearing and the second bearing are sleeved on the bearing support cylinder, the end cylinder is used to connect with the rear end cover of the motor, and the outer surfaces of the connecting cylinder and the end cylinder are provided with oil guide grooves.

6. The motor shaft structure according to claim 1, characterized in that, The rotor shaft includes a cylinder and a first end connecting flange, the first end connecting flange being used to connect with the rotor connecting flange; A flange stop is provided on the end face of the first end connecting flange near the rotor connecting flange, and the end of the rotor connecting flange near the first end connecting flange is fitted onto the flange stop. The first end connecting flange is provided with a first connecting through hole for connecting with the rotor connecting flange.

7. The motor shaft structure according to claim 6, characterized in that, The rotor connecting flange includes a second end connecting flange, a resolver mounting ring, an oil seal ring, and a flange key arranged in sequence. The second end connecting flange, resolver mounting ring, oil seal ring, and flange key are an integral structure. The second end connecting flange is used to connect with the first end connecting flange. The resolver mounting ring is used to install the rotor of the resolver. The oil seal ring is used to cooperate with the oil seal on the front end cover of the motor to achieve sealing. The rotor connecting flange is provided with a third through cavity along the axial direction. The first cavity, the second cavity, and the third cavity are connected.

8. The motor shaft structure according to claim 7, characterized in that, The second end connecting flange has an arc-shaped surface that convexes toward the resolver mounting ring. The edge of the second end connecting flange is provided with several connecting platforms, which are evenly distributed at the edge of the second end connecting flange. Each connecting platform is provided with a second connecting through hole, and the first connecting through hole and the second connecting through hole are provided correspondingly.

9. The motor shaft structure according to claim 1, characterized in that, The rotor shaft and the rotor connecting flange are connected or welded together by a connector, or the rotor shaft and the rotor connecting flange are an integral structure.

10. A drive motor, comprising a housing and a motor shaft, rotor, and stator assembly disposed inside the housing, wherein a rear end cover is provided at one end of the housing and a front end cover is provided at the other end, characterized in that, The motor shaft is the motor shaft structure described in any one of claims 1-9.

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