Driving motor and rotating shaft structure thereof

Abstract

A motor rotating shaft structure disclosed by the present invention is characterized in that the motor rotating shaft structure comprises a rotor shaft barrel, the rotor shaft barrel is provided with a first through cavity arranged along the axis direction in a penetrating manner, the rotor shaft barrel sleeves the outer side of an inner barrel, and the end part of the rotor shaft barrel far away from the inner barrel is provided with a rotor connecting flange; the outer surface of the rotor shaft barrel is connected with a rotor iron core; the inner cylinder is provided with a second through cavity penetrating in the axis 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. According to the motor rotating shaft structure, the overall axial length size of the motor rotating shaft is shortened, so that the length of the radial magnetic flux motor in the axial direction is reduced, and the structural compactness of the motor is better. The invention further discloses a driving motor.

Description

Technical Field

[0001] The present invention relates to the technical field of drive motors, and in particular to a drive motor and a rotating shaft structure thereof. Background Art

[0002] The electric bridge or electric drive assembly used in existing new energy vehicles generally uses a permanent magnet synchronous motor as a power source. If the permanent magnet synchronous motor uses an axial flux motor, although the axial size of the motor can be greatly reduced, the axial flux motor will increase a lot in diameter, and there will be problems in layout and installation, and the cost is high. Therefore, in the prior art, most permanent magnet synchronous motors use radial flux motors.

[0003] The radial flux motor in the prior art, such as Figure 1 As shown, it includes a motor shaft 03, a rotor 02 and a stator 04. Both 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. The radial flux motor is relatively long in the axial direction and has poor structural compactness. It requires more axial length space when installed on a vehicle, which brings inconvenience to installation and use, and is limited in application in installation occasions. Summary of the invention

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

[0005] The invention also provides a driving motor.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] A motor shaft structure, comprising a rotor shaft cylinder, the rotor shaft cylinder is provided with a first through cavity set along the axial direction, the rotor shaft cylinder is sleeved on the outside of an inner cylinder, the end of the rotor shaft cylinder away from the inner cylinder is provided with a rotor connecting flange, the outer surface of the rotor shaft cylinder is connected to a rotor core; the inner cylinder is provided with a second through cavity set along the axial direction;

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

[0009] Optionally, the inner ring of the first bearing and the inner ring of the second bearing are transitionally fitted with the outer surface of the inner cylinder, and the outer ring of the first bearing and the outer ring of the second bearing are interference fitted 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 sleeved on the inner cylinder, and the bearing spacer sleeve is arranged between the first bearing and the second bearing;

[0011] The bearing spacer sleeve comprises a main sleeve body sleeved on the inner cylinder, one end face of the main sleeve body contacts the inner ring end face of the first bearing, and the other end face of the main sleeve body contacts the inner ring end face of the second bearing;

[0012] The outer surface of the main sleeve is provided with a convex ring arranged around the circumference, and the outer surface of the convex ring is spaced a set distance from the inner surface of the corresponding position of the first through cavity;

[0013] The set distance is 0.4-0.8 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 one end close to the main sleeve body is smaller than the width of the convex ring at one end away from the main sleeve body.

[0017] Optionally, the inner cylinder comprises a bearing support cylinder, a connecting cylinder and an end cylinder which are integrally arranged in sequence, and 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 tube, the end tube is used to connect with the rear end cover of the motor, and the outer surfaces of the connecting tube and the end tube are provided with oil guide grooves.

[0019] Optionally, the rotor shaft cylinder comprises a cylinder body and a first end connecting flange, and the first end connecting flange is used to connect with the rotor connecting flange;

[0020] A flange stop is provided on the end surface of the first end connecting flange close to the rotor connecting flange, and one end of the rotor connecting flange close to the first end connecting flange is sleeved on 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 comprises a second end connecting flange, a resolver mounting ring, an oil seal ring and a flange key which are arranged in sequence, wherein the second end connecting flange, the resolver mounting ring, the oil seal ring and the flange key are an integrated structure, the second end connecting flange is used to be connected to the first end connecting flange, the resolver mounting ring is used to install the rotor of the resolver, and 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 through cavity, the second through cavity and the third through cavity are connected.

[0025] Optionally, the disk surface of the second-end connecting flange is an arc-shaped surface convex toward the rotating transformer mounting ring, and a plurality of connecting platforms are arranged on the edge of the second-end connecting flange. The plurality of connecting platforms are evenly distributed at the edge of the second-end connecting flange, and a second connecting through hole is arranged on each connecting platform, and the first connecting through hole and the second connecting through hole are arranged correspondingly.

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

[0027] It can be seen from the above technical scheme that the present invention provides a hollow rotor shaft cylinder for use in conjunction with an inner cylinder, and the first bearing and the second bearing for supporting the motor shaft are built into the gap between the inner cylinder and the rotor shaft cylinder, and the first bearing and the second bearing are arranged within the axial projection range of the rotor core, that is, the two supporting bearings are installed in the axial space corresponding to the rotor core of the motor, shortening the overall axial length of the motor shaft, thereby reducing the length of the radial flux motor in the axial direction, making the motor more compact, and requiring a small axial length space for vehicle installation, which is convenient for installation and use.

[0028] The present invention also provides a driving motor, comprising a housing and a motor shaft, a rotor and a stator assembly arranged inside the housing, a rear end cover being arranged at one end of the housing and a front end cover being arranged at the other end, and the motor shaft is the above-mentioned motor shaft structure.

[0029] The driving motor of the present invention has the above-mentioned motor shaft structure, and thus has the advantages of the above-mentioned motor shaft structure, which will not be described in detail here. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0031] Figure 1 It is a schematic cross-sectional structure diagram of a radial flux motor in the prior art;

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

[0033] Figure 3 A schematic cross-sectional view of a motor shaft structure provided by an embodiment of the present invention;

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

[0035] Figure 5 A schematic cross-sectional view of the bearing spacer sleeve and the 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 A schematic diagram of the structure of a rotor shaft cylinder provided in an embodiment of the present invention;

[0038] Figure 8 A schematic diagram of the structure of a rotor connecting flange provided in an embodiment of the present invention;

[0039] Fig. 9 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] Fig.10 for Fig. 9 Schematic diagram of the cross-sectional structure.

[0041] in:

[0042] 01, first bearing, 02, rotor, 03, motor shaft, 04, stator, 05, second bearing,

[0043] 1. Shell,

[0044] 2. The first bearing,

[0045] 3. Bearing spacer sleeve,

[0046] 301, main sleeve, 302, mounting through hole, 303, convex ring, 304, weight reduction groove,

[0047] 4. Stator assembly,

[0048] 5. Rotor core,

[0049] 6. Second bearing,

[0050] 7. Fixed ring,

[0051] 8. Front cover,

[0052] 9. Oil seal,

[0053] 10. Rotor connection flange,

[0054] 1001, flange key, 1002, second end connecting flange, 1003, third through cavity, 1004, oil seal ring, 1005, rotary transformer mounting ring, 1006, connecting platform, 1007, second connecting through hole,

[0055] 11. Inner tube,

[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,

[0059] 1301, cylinder, 1302, first end connecting flange, 1303, first through cavity, 1304, first connecting through hole, 1305, flange stop,

[0060] 14. The first baffle,

[0061] 15. Positioning pin,

[0062] 16. Second connecting bolt,

[0063] 17. Front sealing cover,

[0064] 18. Rear sealing cover,

[0065] 19. The first connecting bolt,

[0066] 20. Connecting nut,

[0067] 21. Strengthen the rib plate,

[0068] 22. Second baffle. DETAILED DESCRIPTION

[0069] The invention discloses a motor shaft structure, which 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 more compact.

[0070] The invention also discloses a driving motor.

[0071] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

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

[0073] In order to improve the stability of the bearing support, the first bearing 2 and the second bearing 6 are arranged at a certain distance, and the specific length value of the certain distance here is set by those skilled in the art according to actual needs and is not limited here. The second through cavity 1102 and the first through cavity 1303 are both cylindrical through cavities.

[0074] The motor shaft structure of the present invention is provided with a hollow rotor shaft cylinder 13 for use in conjunction with the inner cylinder 11, and the first bearing 2 and the second bearing 6 for supporting the motor shaft are built into the gap between the inner cylinder 11 and the rotor shaft cylinder 13, and the first bearing 2 and the second bearing 6 are arranged within the axial projection range of the rotor core 5, that is, the two supporting bearings are installed in the axial space corresponding to the rotor core 5 of the motor, shortening the overall axial length of the motor shaft, thereby reducing the length of the radial flux motor in the axial direction, making the motor more compact, and requiring a small axial length space for vehicle installation, which is convenient for installation and use.

[0075] Among them, the inner ring of the first bearing 2 and the inner ring of the second bearing 6 are arranged in transition fit with the outer surface of the inner cylinder 11, so that the bearings are easily installed on the inner cylinder 11, and the inner rings of the bearings are also fixed relative to the inner cylinder 11. The outer rings of the first bearing 2 and the outer rings of the second bearing 6 are arranged in interference fit with the inner surface of the rotor shaft cylinder 13, so that the outer rings of the first bearing 2 and the second bearing 6 are tightly connected with the rotor shaft cylinder 13 to rotate, that is, the outer rings of the first bearing 2, the outer rings of the second bearing 6 and the rotor shaft cylinder 13 rotate relative to the inner cylinder 11.

[0076] In order to maintain the axial distance between the inner ring of the first bearing 2 and the inner ring of the second bearing 6, a bearing spacer sleeve 3 for limiting the inner rings of the first bearing 2 and the second bearing 6 is sleeved on the inner cylinder 11, and the bearing spacer sleeve 3 is arranged between the first bearing 2 and the second bearing 6. Specifically, the bearing spacer sleeve 3 includes a main sleeve body 301 sleeved on the inner cylinder 11. In order to facilitate installation on the inner cylinder 11, the main sleeve body 301 is provided with an installation through hole 302 along the axial direction, 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 matched, which not only ensures the position reliability of the bearing spacer sleeve 3 on the inner cylinder 11, but also facilitates installation. When the motor is working, the bearing spacer sleeve 3 and the inner cylinder 11 do not move.

[0077] In order to ensure installation performance, the outer surface of the main sleeve body 301 is provided with a circumferentially arranged convex ring 303, and the difference between the outer surface radius of the convex ring 303 and the radius of the corresponding position of the first through cavity 1303 is 0.4-0.8 mm, so that the outer surface of the convex ring 303 is spaced a set distance from the inner surface of the first through cavity 1303. The 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, so that before the bearing spacer sleeve 3 is not installed and contacted 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, and the bearing spacer sleeve 3 is kept close to the center of the rotating shaft and will not deviate too much from the axis center line position, so that during assembly, the inner cylinder 11 can smoothly penetrate the inner holes of the first bearing 2, the bearing spacer sleeve 3 and the second bearing 6. At the same time, the outer surface of the convex ring 303 and the inner surface of the first through cavity 1303 are separated by a set distance, that is, there is a gap between the surfaces close to each other, which prevents the inner wall of the first through cavity 1303 from interfering or rubbing with the bearing spacer sleeve 3 when the rotor rotates, and avoids damage caused by interference or friction between the two. If the gap is too large, the bearing spacer sleeve 3 loses its centering function, resulting in difficulty in centering and assembly; 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 set distance is 0.4-0.8 mm.

[0078] In order 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 circumferentially arranged around the outer surface of the convex ring 303, or the weight-reducing grooves 304 are arranged 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 is conducive to the flow of lubricating oil between the two bearings. Further, the width of the end of the convex ring 303 close to the main sleeve body 301 is smaller than the width of the end away from the main sleeve body 301, as shown in FIG. Figure 5 As shown, the cross section of the protruding 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 which are arranged in sequence as a whole. Figure 3 and Figure 6 As shown, the bearing support cylinder 1101, the connecting cylinder 1104 and the 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 passes through 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 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 motors that use oil cooling, the motor bearings generally use open bearings. In this case, oil needs to flow through the bearings for lubrication. In order to facilitate the flow of lubricating oil, the outer surfaces of the connecting cylinder 1104 and the end cylinder 1105 are provided with oil guide grooves 1106 that are connected and arranged. By providing the oil guide grooves 1106, the oil in the inner cavity of the motor can be guided to flow to the two bearings, thereby producing a better lubrication effect. The position of the bearing support cylinder 1101 near the connecting cylinder 1104 is provided with a limit ring 1103, such as 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 1103, and the other side 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 fixing ring 7. The fixing ring 7 is used to clamp the second bearing 6 and a series of parts on its left side together on the inner cylinder 11 to achieve axial limitation. In one embodiment, the fixing ring 7 is threadedly connected to the inner cylinder 11 for easy disassembly and maintenance. In other embodiments, the fixing ring 7 and the inner cylinder 11 can also be connected by welding, interference connection or other commonly used connection methods in the field according to actual conditions.

[0081] For water-cooled motors or air-cooled motors, since there is no flowing oil inside the motor to lubricate the bearings, 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, there is no need to set an oil guide groove 1106 on the inner cylinder 11 of the motor with the closed bearing installed.

[0082] In one embodiment, the rotor shaft cylinder 13 includes a cylinder body 1301 and a first end connecting flange 1302. Figure 7As shown, the first end connection flange 1302 is used to connect with the rotor connection flange 10. A flange stop 1305 is provided on the end surface of the first end connection flange 1302 close to the rotor connection flange 10, and one end of the rotor connection flange 10 close to the first end connection flange 1302 is sleeved on the flange stop 1305. A first connection through hole 1304 for connecting with the rotor connection flange 10 is provided on the first end connection flange 1302. The rotor connection flange 10 is provided 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 connection flange 10. One end of the rotor core 5 is limited by the first baffle 14, and the other end is limited by the second baffle 22. The first baffle 14 is connected to the rotor shaft cylinder 13 by thread or other commonly used connection methods. The second baffle 22 is sleeved on the stepped surface of the end of the rotor shaft cylinder 13, and the second baffle 22 is pressed between the first end connection 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] Correspondingly, the rotor connection flange 10 includes a second end connection flange 1002, a rotating transformer mounting ring 1005, an oil seal ring 1004 and a flange key 1001 which are arranged in sequence. Specifically, the second end connection flange 1002, the rotating transformer mounting ring 1005, the oil seal ring 1004 and the flange key 1001 are an integrated structure, such as Figure 8 As shown. The second end connection flange 1002 is used to connect with the first end connection flange 1302, the rotary transformer mounting ring 1005 is used to install the rotor of the rotary transformer, 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, and the flange key 1001 is used to connect with the structure of external power torque transmission, specifically, it can be connected with a gear or a shaft. The rotor connection flange 10 is provided with a third through cavity 1003 along the axial direction, that is, the rotor connection 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, which is convenient for weight reduction on the one hand, and improves the freedom of design on the other hand. The internal hollow structure can pass through the shaft parts, or install gear parts, which is convenient for expanding to realize more functions and structures, and is suitable for more applications.

[0084] Furthermore, the disk surface of the second end connecting flange 1002 is an arc-shaped surface convex toward the rotating transformer mounting ring 1005, such as Figure 8As shown, the edge of the second end connection flange 1002 is provided with a plurality of connection platforms 1006, and the plurality of connection platforms 1006 are evenly distributed at the edge of the second end connection flange 1002. Each connection platform 1006 is provided with a second connection through hole 1007, and the first connection through hole 1304 is provided correspondingly to the second connection through hole 1007. In one embodiment, the second end connection flange 1002 and the first end connection flange 1302 are connected by a first connection bolt 19 and a connection nut 20, as shown in FIG. Fig. 9 and Fig.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 may be used for installation, or the rotor shaft barrel 13 and the rotor connecting flange 10 are connected together by welding, or the rotor shaft barrel 13 and the rotor connecting flange 10 are an integrated structure, that is, a single part.

[0085] In order to seal the hollow structure of the motor shaft structure, a front sealing cover 17 is provided at the front end of the third through cavity 1003 of the rotor connection flange 10, and a rear sealing cover 18 is provided at the rear end of the second through cavity 1102. The front sealing cover 17 and the rear sealing cover 18 are provided to prevent the oil in the cavity of the motor shaft structure of the oil-cooled motor from flowing out, and to prevent external debris or moisture from entering the cavity of the motor shaft structure.

[0086] The motor shaft structure of the present 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 to support the motor shafts extending from both ends. The supporting bearings are built into the middle cavity of the shaft, so that the axial length of the motor shaft can be greatly shortened. By providing a bearing spacer sleeve 3, it can meet the requirements of the bearing positioning function and the requirements of assembly and disassembly in the process. The rotor core 5 is combined with the rotor connecting flange 10 to realize the function of transmitting power torque of the motor shaft. The rotor shaft cylinder 13 and the rotor connecting flange 10 are separated into two parts, and the interior is hollow, so more parts can be installed inside. For example, the internal space can accommodate or install gears, or transmission shafts, or other bearings and other parts, thereby obtaining a more compact structure and lighter weight, which is suitable for more application scenarios.

[0087] The present invention also provides a driving motor, comprising a housing 1 and a motor shaft, a rotor and a stator assembly 4 arranged inside the housing 1, a rear end cover 12 being arranged at one end of the housing 1, and a front end cover 8 being arranged at the other end, and the motor shaft is the above-mentioned motor shaft structure. The rear end cover 12 is welded to the inner cylinder 11 and the housing 1 or connected by a connector. When the rear end cover 12 is welded to the inner cylinder 11 and the housing 1, in order to improve the structural strength, a reinforcing rib plate 21 is arranged on the surface of the rear end cover 12 close to the inner cavity of the motor. The rear end cover 12 is used to cover and seal the rear part of the inner cavity of the motor. A front end cover 8 is arranged at the power output end of the rotor of the motor. The front end cover 8 covers the front part of the inner cavity of the motor and provides an installation position for the oil seal 9. The front end cover 8 is connected to the housing 1 by a second connecting bolt 16 and a positioning pin 15, which facilitates 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", "inside", "outside", etc., indicating the orientation or position relationship are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on this solution.

[0089] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of this solution, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

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

[0091] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one 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 present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A motor shaft structure, characterized in that: It comprises a rotor shaft cylinder, the rotor shaft cylinder is provided with a first through cavity which is set through along the axial direction, the rotor shaft cylinder is sleeved on the outside of the inner cylinder, the end of the rotor shaft cylinder away from the inner cylinder is provided with a rotor connecting flange, and the outer surface of the rotor shaft cylinder is connected to the rotor core; the inner cylinder is provided with a second through cavity which is set through along the axial direction; A first bearing and a second bearing are disposed between the inner cylinder and the rotor shaft cylinder, and the first bearing and the second bearing are disposed within the axial projection range of the rotor core.

2. The motor shaft structure according to claim 1, characterized in that: The inner ring of the first bearing and the inner ring of the second bearing are arranged in transition fit with the outer surface of the inner cylinder, and the outer ring of the first bearing and the outer ring of the second bearing are arranged in 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 inner cylinder is sleeved with a bearing spacer sleeve for limiting the inner rings of the first bearing and the second bearing, and the bearing spacer sleeve is arranged between the first bearing and the second bearing; The bearing spacer sleeve comprises a main sleeve body sleeved on the inner cylinder, one end face of the main sleeve body contacts the inner ring end face of the first bearing, and the other end face of the main sleeve body contacts the inner ring end face of the second bearing; The outer surface of the main sleeve is provided with a convex ring arranged around the circumference, and the outer surface of the convex ring is spaced a set distance from the inner surface of the corresponding position of the first through cavity; The set distance is 0.4-0.8 mm.

4. The motor shaft structure according to claim 3, characterized in that: The convex ring is provided with a plurality of 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 one end close to the main sleeve body is smaller than the width of the convex ring at one end away from the main sleeve body.

5. The motor shaft structure according to claim 1, characterized in that: The inner cylinder comprises a bearing support cylinder, a connecting cylinder and an end cylinder which are arranged in sequence in an integrated manner, 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 tube, the end tube is used to connect with the rear end cover of the motor, and the outer surfaces of the connecting tube and the end tube are provided with oil guide grooves.

6. The motor shaft structure according to claim 1, characterized in that: The rotor shaft cylinder comprises a cylinder body and a first end connecting flange, wherein the first end connecting flange is used to connect with the rotor connecting flange; A flange stop is provided on the end surface of the first end connecting flange close to the rotor connecting flange, and one end of the rotor connecting flange close to the first end connecting flange is sleeved on 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 connection flange comprises a second end connection flange, a resolver mounting ring, an oil seal ring and a flange key which are arranged in sequence, wherein the second end connection flange, the resolver mounting ring, the oil seal ring and the flange key are an integrated structure, the second end connection flange is used to be connected to the first end connection flange, the resolver mounting ring is used to install the rotor of the resolver, and 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 through cavity, the second through cavity and the third through cavity are connected.

8. The motor shaft structure according to claim 7, characterized in that: The disk surface of the second-end connecting flange is an arc-shaped surface convex toward the rotating transformer mounting ring. A plurality of connecting platforms are arranged at the edge of the second-end connecting flange. The plurality of connecting platforms are evenly distributed at the edge of the second-end connecting flange. A second connecting through hole is arranged on each connecting platform. The first connecting through hole and the second connecting through hole are arranged correspondingly.

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

10. A driving motor, comprising a housing and a motor shaft, a rotor and a stator assembly arranged inside the housing, wherein a rear end cover is arranged at one end of the housing and a front end cover is arranged at the other end, characterized in that: The motor shaft is the motor shaft structure according to any one of claims 1 to 9.

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