Rotor and bearing integrated cooling and lubricating structure, motor rotor structure and motor system

Abstract

The invention discloses a rotor and bearing integrated cooling and lubricating structure, a motor rotor structure and a motor system, and belongs to the technical field of motor cooling and lubrication, and the rotor and bearing integrated cooling and lubricating structure comprises a rotor oil slinging shaft which is internally provided with a through cavity and is provided with a radial through hole in the side wall; the hollow rotating shaft is in interference fit with the rotor oil throwing shaft, and two ends of the hollow rotating shaft are provided with bearing oil ducts extending outwards in an inclined manner; radially-distributed radiating ribs are arranged in the rotor iron core, rotor heat conduction pipes are embedded in the radiating ribs, the heat absorption ends of the rotor heat conduction pipes are close to the rotor heat source, and the condensation ends of the rotor heat conduction pipes are embedded in the hollow rotating shaft. Through integrated design of the rotor heat conduction pipe, the hollow shaft cooler and the bearing ring lower lubrication cooler, the cooling effect of the hollow shaft cooler is effectively improved, high integration of rotor cooling and bearing lubrication cooling is completed, a feasible thought is provided for a light-weight cooling scheme of a large-size rotor, and the application prospect is wide. The problems that the number of matched operation devices of the motor is large, and the system redundancy is high are effectively solved.

Description

Technical Field

[0001] The present invention belongs to the technical field of motor cooling and lubrication, and more specifically, relates to an integrated cooling and lubrication structure for a rotor bearing, a motor rotor structure, and a motor system. Background Art

[0002] In recent years, high-power and high-speed motors have received more attention due to their less material usage and higher efficiency. Power density has become one of the most important criteria in many application scenarios. High speed is a key way to achieve high power density in motors. However, rotor losses (including bearing losses, air friction losses, and rotor eddy current losses) will increase significantly with the increase in speed, which will lead to a sharp rise in rotor temperature, thus posing a challenge to rotor cooling.

[0003] Forced air cooling is the most commonly used cooling method for rotor cooling. However, this cooling method will cause significant vibration noise and air friction losses, and air can be almost regarded as a heat insulation material due to its low thermal conductivity. Therefore, forced air cooling cannot fully meet the rotor heat dissipation requirements of high-speed motors. Since the thermal conductivity of oil is higher than that of air, rotor liquid cooling has become a more effective method for rotor thermal management. Currently, there are liquid cooling solutions that immerse the rotor in oil. Immersion oil cooling can shorten the heat transfer path between the heat source and the coolant, effectively reducing the rotor temperature. However, the high-speed rotation of the rotor may cause a large amount of oil friction loss, which limits the use of immersion oil cooling. In addition, air shaft cooling, as a new type of rotor liquid cooling solution, has also been widely used. This solution can balance cooling performance, friction loss, and vibration noise. In the relevant records of the prior art, a rotor hollow shaft is provided in the motor housing. The rotor shaft is provided with a reducer output shaft through a meshing spline. A cooling oil pipe is provided in the motor housing, and the cooling oil pipe is in clearance fit with the rotor shaft. The internal oil passage of the rotor is realized through the design of the hollow rotor shaft and the rotor shaft oil guide pipe. Through the design of oil holes with a certain size on the rotor shaft and the rotor shaft oil guide pipe, the design of the corresponding oil path guiding parts on the rotor shaft, and the oil distribution structure on the housing, the integration of rotor cooling function, stator cooling function, bearing lubrication function, and spline lubrication function is realized. The specific structure is as Figure 1 and Figure 2 shown. The rotor cooling solution of this technical solution is hollow shaft cooling, but the rotor heat source (permanent magnet) is far from the cooling medium, and the cooling effect is poor. And the bearing lubrication solution adopts spray lubrication, which has a simple structure but poor lubrication effect at high speed rotation. However, the existing hollow shaft cooling has the problem that the cooling medium is far from the heat source and the cooling performance is poor.

[0004] In addition, in the existing lubrication technology for the main shaft bearings of aero-engines, under-ring lubrication has become a commonly used lubrication method because it can maintain better lubrication and cooling effects for the bearings during high-speed rotation of the bearings. However, in the motor cooling and lubrication system, the bearings are often lubricated by opening oil channels on the housing, which increases the complexity of the housing design and raises the processing difficulty. Summary of the Invention

[0005] In view of the above defects or improvement requirements of the prior art, the present invention provides an integrated cooling and lubrication structure for a rotor bearing, a motor rotor structure, and a motor system, thereby solving the technical problem of insufficient cooling efficiency of the rotor heat source by ordinary hollow shaft cooling.

[0006] To achieve the above object, according to one aspect of the present invention, there is provided an integrated cooling and lubrication structure for a rotor bearing, including:

[0007] A rotor oil-slinging shaft, which has a through cavity inside and radial through holes are provided on the side wall;

[0008] A hollow rotating shaft, which is in interference fit with the rotor oil-slinging shaft, and bearing oil channels extending obliquely outward are provided at both ends thereof;

[0009] A rotor core, which has radially distributed heat dissipation ribs inside, and rotor heat conduction tubes are embedded in the heat dissipation ribs. The heat absorption end of the rotor heat conduction tube is close to the rotor heat source, and the condensation end of the rotor heat conduction tube is embedded inside the hollow rotating shaft;

[0010] Cooling oil enters from the rear end of the rotor oil-slinging shaft, is sprayed onto the inner wall of the hollow rotating shaft through the radial through holes, part of the cooling oil flows into the bearing oil channels along the inner wall of the hollow rotating shaft to achieve under-ring lubrication, and the remaining cooling oil flows out from the front end of the rotor oil-slinging shaft to lubricate the spline.

[0011] Preferably, the inner wall of the hollow rotating shaft has an inclination angle, and the inclination angle is designed to guide the cooling oil to flow towards the bearing oil channels under the action of centrifugal force to avoid oil accumulation.

[0012] Preferably, it further includes a motor front bearing and a motor rear bearing, and the motor front bearing and the motor rear bearing are connected in series with the cooling oil circuit of the hollow rotating shaft through the bearing oil channels.

[0013] Preferably, the rotor heat conduction tubes are arranged radially in the heat dissipation ribs of the rotor core and are fixed by interference fit or sealant.

[0014] More preferably, the installation method of the rotor heat pipes is as follows: radially through holes are drilled in the silicon steel sheets before laminating the rotor core, and the heat pipes are inserted and then laminated as a whole; or holes are drilled after assembling the rotor core and the hollow rotating shaft, and they are fixed by high thermal conductivity sealant.

[0015] Preferably, the rotor heat pipe is made of a high thermal conductivity material, including but not limited to copper, aluminum or composite materials.

[0016] Preferably, the interior of the rotor heat pipe is filled with a working medium, and the centrifugal force is used to accelerate the flow of the working medium towards the condensation end, thereby improving the heat conduction efficiency.

[0017] Preferably, a first oil slinging hole is provided at the front end of the rotor oil slinging shaft, and the first oil slinging hole is used to guide the cooling oil to the meshing gap between the spline and the hollow rotating shaft.

[0018] According to another aspect of the present invention, a motor rotor structure is provided, including the above-mentioned integrated cooling and lubrication structure for the rotor bearing.

[0019] According to another aspect of the present invention, a motor system is provided, including the above-mentioned motor rotor structure.

[0020] Generally speaking, compared with the prior art by the above technical solution conceived by the present invention, by additionally designing a radial rotor heat pipe inside the rotor core, the heat conduction ability of the rotor core is increased, and a better hollow shaft cooling effect is achieved; and the bearing cooling and lubrication flow channel and the rotor hollow shaft flow channel are designed in a series structure to complete the integration of rotor cooling and bearing lubrication cooling, eliminating the supporting equipment for bearing lubrication cooling, reducing the complexity of the motor system, and improving the cooling efficiency of the motor. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 is a schematic cross-sectional view of the cooling and lubrication structure of the electric drive rotor in the prior art;

[0022] Figure 2 is a schematic cross-sectional view of the connection between the oil guiding pipe and the rotor in the prior art;

[0023] Figure 3 is a schematic longitudinal cross-sectional view of the integrated cooling and lubrication structure of the rotor bearing in the embodiment of the present invention;

[0024] Figure 4 is a schematic cross-sectional view of the integrated cooling and lubrication structure of the rotor bearing in the embodiment of the present invention.

[0025] In all the drawings, the same reference numerals are used to represent the same elements or structures, where: 1 - spline; 2 - hollow rotating shaft; 3 - front motor bearing; 4 - front rotor pressing plate; 5 - rotor sheath; 6 - rotor magnet; 7 - rotor heat pipe; 8 - rear rotor pressing plate; 9 - rear motor bearing; 10 - rotor oil slinging shaft; 11 - rotor core; 12 - rotor core cavity. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0026] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only for explaining the present invention and are not used to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0027] As Figure 3 and Figure 4 shown, in view of the problems of insufficient cooling efficiency of the rotor heat source (permanent magnet) by ordinary hollow shaft cooling and the additional bearing lubrication and cooling device, the present invention proposes a rotor bearing integrated cooling and lubrication structure, a motor rotor structure, and a motor system. The specific structure and working principle are as follows:

[0028] The rotor bearing integrated cooling and lubrication structure is as Figure 3 shown. This structure mainly includes a rotor oil slinger shaft 10, a hollow rotating shaft 2, a rotor core 11, and a rotor heat conduction tube 7. The hollow rotating shaft 2 is in interference fit with the rotor oil slinger shaft 10, and both ends of the hollow rotating shaft 2 are provided with bearing oil channels extending obliquely outwards; the interior of the rotor core 11 is provided with radially distributed heat dissipation ribs, and the rotor heat conduction tube 7 is embedded in the heat dissipation ribs. The heat absorption end of the rotor heat conduction tube 7 is close to the rotor heat source, and the condensation end of the rotor heat conduction tube 7 is embedded inside the hollow rotating shaft 2; cooling oil enters from the rear end of the rotor oil slinger shaft 10, is sprayed onto the inner wall of the hollow rotating shaft 2 through the radial through holes, part of the cooling oil flows along the inner wall of the hollow rotating shaft 2 into the bearing oil channel to achieve under-ring lubrication, and the remaining cooling oil flows out from the front end of the rotor oil slinger shaft 10 to lubricate the spline 1.

[0029] Specifically, the rotor heat pipe 7 in the present invention is designed in a strip shape and arranged radially in the heat dissipation ribs of the rotor core 11. The heat absorption end of the rotor heat pipe 7 is close to the rotor heat source (such as a permanent magnet), and the condensation end is embedded inside the hollow rotating shaft 2. The rotor heat pipe 7 is made of a high thermal conductivity material (such as copper, aluminum or a composite material) to ensure efficient heat conduction. The rotor heat pipe 7 can be assembled during the rotor processing. Two assembly methods are provided in the present invention: before the silicon steel sheets of the rotor core 11 are laminated, radially penetrating holes are drilled at the axial corresponding positions of the core silicon steel sheets, and the shape and size of the holes match those of the heat pipe. Then, the heat pipe is inserted along the radial holes, and the rotor core with the heat pipe is integrally laminated. An interference fit is formed between the rotor heat pipe 7 and the rotor core 11, and a high-temperature resistant sealant is filled at the gap at both ends where the rotor heat pipe 7 and the rotor core 11 are fitted, so as to play the role of fixing the rotor heat pipe 7 and sealing. Finally, holes are drilled at the corresponding positions of the rotating shaft according to the shape of the heat pipe after lamination, and the size of the holes can be slightly larger. It should be noted that this assembly method is only applicable to metal heat pipes made of metal materials such as copper and aluminum. In addition, holes can also be drilled according to the design requirements after the silicon steel sheets of the rotor core are laminated and integrally assembled with the rotating shaft. The shape and size of the holes match those of the rotor heat pipe, and the shaft end of the hole can be slightly larger. After drilling, a highly thermally conductive sealant (such as silica gel containing boron nitride filler) is evenly applied to the inner surface of the hole and the surface of the rotor heat pipe. Then, the rotor heat pipe is inserted radially into the hole, and after the shaft end is completely filled with the sealant, a curing treatment (such as high-temperature baking) is carried out. This assembly method uses the adhesive force and thermal conductivity of the sealant to achieve auxiliary fixation. This assembly method is applicable not only to rotor heat pipes made of metal materials but also to rotor heat pipes that rely on the phase change of the internal working fluid to achieve heat transfer.

[0030] For further illustration, the oil circuit of the integrated cooling and lubrication structure of the rotor bearing in the present invention is as Figure 3 shown. The cooling oil enters the oil slinger from the rear end of the rotor oil slinger 10. The rotor oil slinger 10 has an interference fit with the hollow rotating shaft 2, so that the rotor oil slinger 10 can rotate synchronously with the hollow rotating shaft 2 during the operation of the motor. The oil slinger is of a front-back penetrating type, and radially penetrating holes are provided on the middle side wall of the oil slinger. Part of the cooling oil in the cavity of the rotor oil slinger 10 will be sprayed along the fine oil holes onto the inner wall of the hollow rotating shaft 2 under the drive of centrifugal force to cool the rotating shaft and the rotor heat pipe 7, thereby ensuring the thermal safety of key rotor components such as the rotor permanent magnet and the carbon fiber protective sleeve. The remaining cooling oil will flow out from the first oil slinger hole at the front end of the rotor oil slinger 10 and flow into the meshing gap between the spline 1 and the rotating shaft to play the role of lubricating the spline 1.

[0031] Further explanation: The inner wall of the hollow rotating shaft 2 is designed with a certain inclination angle. Therefore, the cooling oil sprayed onto the inner wall of the rotating shaft can flow along the inner wall of the rotating shaft towards the bearing oil passage on the inner wall under the action of the centrifugal force during the rotation of the rotating shaft, without accumulating on the inner wall of the rotating shaft. The bearing oil passages inclined outward are designed at both ends of the rotating shaft cavity. The cooling oil can flow along the bearing oil passage to the lubricating oil groove of the bearing base, and then overflow from the oil hole of the bearing base along the base oil passage to achieve the under-ring lubrication function of the bearing.

[0032] Further explanation: Since the cooling end of the rotor heat pipe 7 is placed in the rotating shaft, the heat transferred to the rotating shaft will be carried away by the cooling oil on the inner wall of the rotating shaft, thus completing a working heat cycle. When the rotor rotates at a high speed, the centrifugal force will cause the working medium inside the rotor heat pipe 7 to flow towards the condensation end, thereby accelerating the heat transfer. The action of the centrifugal force makes the flow of the working medium inside the heat pipe more efficient, further improving the cooling effect of the rotor heat pipe 7. In addition, under the action of the centrifugal force, the cooling oil is evenly distributed on the inner wall of the rotating shaft, forming a uniform oil film. This oil film can effectively carry away the heat at the condensation end of the rotor heat pipe 7, further improving the cooling effect.

[0033] Further explanation: The integrated cooling and lubrication structure of the rotor bearing proposed by the present invention, by assisting in designing the radial rotor heat pipes made of high thermal conductivity materials in the heat dissipation of the large-size rotor core, greatly improves the heat conduction ability of the rotor core while maintaining the lightweight of the rotor, and thus effectively improves the cooling effect of the hollow shaft cooling. By designing the series-connected internal flow channels of the hollow rotating shaft and the bearing flow channels, the rotor cooling oil can enter the bearing flow channel to provide under-ring lubrication cooling for the bearing after cooling the rotating shaft and the rotor heat pipe, thus eliminating the need for additional bearing cooling and lubrication devices in the motor system and reducing the weight of the motor system. The realization of the integrated cooling and lubrication structure of the rotor bearing enables the motor system to be effectively simplified in fields such as aviation where the operating environment is harsh and the requirements for volume and weight are strict, improving the adaptability of the motor to various operating environments.

[0034] Those skilled in the art can easily understand that the above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. An integrated cooling and lubrication structure for a rotor bearing, characterized in that, Comprising: A rotor oil slinger shaft (10) having a through cavity inside and a radially through hole formed in its side wall; A hollow rotating shaft (2) which is in interference fit with the rotor oil slinger shaft (10) and has bearing oil passages extending obliquely outwards at both ends; A rotor core (11) having radially distributed heat dissipation ribs, with rotor heat conducting tubes (7) embedded in the heat dissipation ribs. The heat absorption end of the rotor heat conducting tube (7) is close to the rotor heat source, and the condensation end of the rotor heat conducting tube (7) is embedded inside the hollow rotating shaft (2); Cooling oil enters from the rear end of the rotor oil slinger shaft (10), is sprayed onto the inner wall of the hollow rotating shaft (2) through the radially through hole. Part of the cooling oil flows along the inner wall of the hollow rotating shaft (2) into the bearing oil passage to achieve under-ring lubrication, and the remaining cooling oil flows out from the front end of the rotor oil slinger shaft (10) to lubricate the spline (1).

2. The integrated cooling and lubrication structure of a rotor bearing according to claim 1, wherein The inner wall of the hollow rotating shaft (2) has an inclination angle.

3. The integrated cooling and lubrication structure of a rotor bearing according to claim 1, characterized in that, It further includes a motor front bearing (3) and a motor rear bearing (9). The motor front bearing (3) and the motor rear bearing (9) are in series with the cooling oil passage of the hollow rotating shaft (2) through the bearing oil passage.

4. The integrated cooling and lubrication structure of a rotor bearing according to claim 1, characterized in that, The rotor heat conducting tubes (7) are arranged radially in the heat dissipation ribs of the rotor core (11) and are fixed by interference fit or sealant.

5. A rotor-bearing integrated cooling and lubrication structure according to claim 1, characterized in that, The rotor heat conducting tubes (7) are made of copper, aluminum or composite materials.

6. The integrated cooling and lubrication structure of a rotor bearing according to claim 1, characterized in that The inside of the rotor heat conducting tubes (7) is filled with a working fluid.

7. The integrated cooling and lubrication structure of a rotor bearing according to claim 1, characterized in that, The front end of the rotor oil slinger shaft (10) is provided with a first oil slinger hole for guiding the cooling oil to the meshing gap between the spline (1) and the hollow rotating shaft (2).

8. A motor rotor structure, characterized in that, Comprising the rotor bearing integrated cooling and lubrication structure according to any one of claims 1-7.

9. A motor system, characterized in that, Comprising the motor rotor structure according to claim 8.

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