CN116780821A - Rotor shaft and motor - Google Patents

Abstract

The invention relates to a rotor shaft (1) for a motor, which has a hollow portion (2) in which a cooling pipe (3) for transporting cooling liquid is provided. The cooling pipe (3) 3) There are cooling pipe oil outlets (31, 32) in the radial direction of the rotor shaft (1). According to the design of the present invention, a fluid distribution part (4) is sleeved on the outer periphery of the cooling tube (3), and the fluid distribution part (4) and the cooling tube (3) form a sealed cavity ( 5), and the gap between the fluid distribution member (4) and the hollow portion (2) forms a cooling channel (6), wherein the cooling pipe oil outlet holes (31, 32) are provided in the fluid Outside of the distribution part (4). Furthermore, the invention relates to an electric machine having the above-mentioned rotor shaft.

Description

Rotor shaft and motor

Technical field

The present invention relates to the field of motors, and in particular to a cooling structure of the motor.

Background technique

Currently, new energy vehicles that are driven by electric energy or are driven by a mixture of electric energy and fuel are receiving more and more attention. In various new energy vehicles, one or more motors are usually installed. Since the motor rotor rotates at an extremely high speed (up to more than 18,000 rpm), the heat generated is very large, and the motor rotor needs to be cooled. At present, the cooling method adopted by advanced electric drive manufacturers at home and abroad is to use coolant for water cooling in the rotor shaft of the motor. Usually a hollow rotor shaft is used, and a cooling pipe is set inside the shaft to inject cooling oil for cooling.

CN 213754129 U discloses an electric machine rotor which has a hollow rotor shaft. There is a cooling opening in the middle of the rotor shaft. The cooling medium is injected from the inlet of the rotor shaft, flows out from the cooling opening into the hollow part of the rotor shaft, and then flows out from the oil outlet to cool the rotor.

In the prior art, the cooling medium that enters the space formed between the cooling tube and the shaft hollow is limited by the rotation speed of the rotor shaft, the amount of oil entering the space, and the inclination angle of the rotor shaft when the vehicle is running. Especially when the amount of oil is insufficient, it cannot The cooling effect is poor when the shaft hollow is filled and when the rotor shaft speed is low. In order to obtain greater oil pressure, the entire hollow part of the shaft needs to be filled with cooling medium. However, the volume of the hollow part of the shaft is too large, requiring more time and more cooling medium to fill, which increases manufacturing and operating costs.

Contents of the invention

The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide a cooling system for the motor rotor that has a simple structure and is cheap to manufacture.

The technical problem is solved by a rotor shaft for an electric machine. The rotor shaft has a hollow part, and a cooling pipe for transporting cooling liquid is provided in the hollow part. The cooling pipe has a cooling pipe oil outlet hole in the radial direction of the rotor shaft. According to the design of the present invention, a fluid distribution component is sleeved on the outer periphery of the cooling tube, the fluid distribution component and the cooling tube form a sealed cavity, and the gap between the fluid distribution component and the hollow portion forms a cooling channel, wherein, The cooling pipe oil outlet is arranged outside the fluid distribution part.

According to the design solution of the present invention, due to the provision of the fluid distribution member, the volume of the space formed between the cooling tube and the hollow part of the rotor shaft is reduced. It is further preferred that the volume of the sealed cavity is larger than the volume of the cooling channel. Since the volume of the cooling channels is reduced, it is easy to fill and quickly build up the appropriate oil pressure. When the vehicle is running, the coolant is not limited by the rotor shaft speed, the amount of oil entering the cooling channel, and the rotor shaft inclination angle. Since a sealed cavity is formed between the fluid distribution piece and the cooling tube, no coolant enters the interior, so less coolant can be added, thereby reducing the total amount of coolant on the rotor shaft and reducing material costs. Compared with the existing technology, only a fluid distribution component is added, the motor rotor shaft has a simple structure, is easy to manufacture, and has low cost.

According to a preferred embodiment of the invention, the fluid distribution element is fixed on the outer periphery of the cooling tube by welding. The fluid distribution part and the cooling pipe can be integrally formed, that is, made into one part, thereby reducing the number of parts; the fluid distribution part and the cooling pipe can also be fixedly connected by welding or other methods. The welding process is simple, and the use of welding can eliminate the need for seals between the fluid distribution part and the cooling tube, saving manufacturing costs. It is further preferred that the fluid distribution part and/or the cooling tube are made of plastic or aluminum alloy. The fluid distribution piece and the cooling tube can be made of the same material or different materials. Plastics and aluminum alloys are both lightweight materials that can reduce the overall weight of a structure.

According to a preferred embodiment of the present invention, the cooling pipe has a first cooling pipe oil outlet close to the oil inlet of the rotor shaft and a second cooling pipe oil outlet far away from the oil inlet, wherein the first cooling pipe oil outlet The hole diameter is smaller than the hole diameter of the oil outlet hole of the second cooling pipe. In the prior art, because the oil outlet hole of the first cooling pipe is close to the oil inlet, the oil pressure is relatively large; the oil outlet hole of the second cooling pipe is far away from the oil inlet, and there will be losses during transportation. The oil pressure at the oil hole is less than The first cooling pipe oil outlet hole. Therefore, the aperture of the oil outlet hole of the first cooling pipe is set to be smaller than the aperture of the oil outlet hole of the second cooling pipe, so that the oil output of the two oil holes can be made as uniform as possible. It is further preferred that the first cooling pipe oil outlet hole and the second cooling pipe oil outlet hole are respectively located at both axial ends of the cooling pipe, and the fluid distribution member is located between the first cooling pipe oil outlet hole and the second cooling pipe oil outlet hole. between.

According to a preferred embodiment of the present invention, the rotor shaft has a first rotor shaft oil outlet hole close to the oil inlet of the rotor shaft and a second rotor shaft oil outlet hole away from the oil inlet, wherein the first rotor shaft oil outlet hole The diameter of the hole is smaller than the diameter of the second rotor shaft oil outlet hole so that the coolant can be evenly distributed to both ends of the end winding. It is further preferred that the axial end of the cooling tube remote from the oil inlet of the rotor shaft is closed. One axial end of the cooling pipe has an oil inlet, and the other axial end is designed to be closed, thereby eliminating the need for oil plug sealing. Even if the cooling pipe is damaged, no oil plug will fall into the motor and cause damage to the motor. Cause secondary damage.

In addition, the above technical problem can also be solved by an electric motor having the rotor shaft mentioned above.

Description of drawings

The present invention is further described below in conjunction with the accompanying drawings. The same reference numerals are used in the figures to identify identical or functionally identical components. The attached picture is:

Figure 1 shows a cross-sectional view of a motor rotor designed according to the prior art;

Figure 2 shows a cross-sectional view of a motor rotor designed according to a preferred embodiment of the present invention.

In the absence of any explicit limitation, both “axial direction” and “radial direction” in the present invention refer to the axial direction and radial direction of the motor rotor shaft.

Detailed ways

Specific embodiments of the rotor shaft according to the present invention will be described below with reference to the accompanying drawings. The following detailed description and drawings are used to illustrate the principles of the invention by way of example. The invention is not limited to the described preferred embodiments, and the scope of protection of the invention is defined by the claims.

Figure 1 shows a cross-sectional view of a motor rotor designed according to the prior art. As shown in Figure 1, the motor rotor 8 is sleeved on the rotor shaft 1, and balance plates for cooling are provided at both axial ends of the motor rotor 8. The rotor shaft 1 is provided hollow and has a hollow portion 2 . Usually, the rotor shaft 1 is composed of three parts, which are fixed together by welding. Since the inner diameter of the rotor shaft 1 is generally large, the rotor shaft 1 is usually designed as a concave hollow structure to reduce its weight. As shown in Figure 1, there are internal cones on both sides of the rotor shaft. A cooling pipe 3 is provided along the axial direction in the middle of the rotor shaft 1 , and a plurality of cooling pipe oil outlets 30 are provided in the radial direction of the cooling pipe 3 for transporting the cooling liquid from the oil inlet 7 to the cooling pipe 3 and the hollow part 2. The flow path of the coolant is shown by the arrow in the figure. An oil plug 9 is provided at the end of the cooling pipe 3 away from the oil inlet 7 to prevent the cooling liquid from flowing out from the other side of the cooling pipe 3 .

The coolant flowing out from the cooling pipe oil outlet hole 3 into the space formed between the cooling pipe 3 and the hollow part 2 can flow along the conical surface of the rotor shaft under the action of centrifugal force, and then discharge oil through the rotor shaft provided on the rotor shaft 1 Hole 20 exits to cool the rotor balance plate and stator end windings. The coolant flows along the conical surface of the rotor shaft under the action of centrifugal force, so it is limited by the rotor shaft speed, the amount of coolant oil, and the inclination angle of the rotor shaft when the vehicle is running. Especially when the amount of oil is insufficient, the hollow part cannot be filled without oil pressure. 2, the cooling effect will be very poor. In order to obtain greater oil pressure and better cooling effect, the hollow part 2 must be filled with coolant. However, the volume of the hollow part 2 is too large and requires more time and more oil to fill. In addition, the rotor shaft 1 has inner conical surfaces on both sides, with larger inner diameters at both ends and smaller inner diameters in the middle. Therefore, the rotor shaft must be divided into three parts, which will increase the manufacturing cost. Since the oil plug 9 is provided, if oil leaks between the oil plug 9 and the cooling pipe 3, it will affect the amount of oil entering the hollow part 2 of the cooling pipe 3, and if the oil plug 9 is loosened from the cooling pipe 3, the oil plug 9 will It will fall into the motor and cause damage to the motor.

In order to overcome the above shortcomings, the present invention improves the design of the rotor shaft 1, as shown in Figure 2. Identical components are no longer described here, and improved structural features are described in detail. As shown in the figure, the cooling structure according to the present invention is divided into two parts, namely the cooling pipe 3 and the fluid distribution part 4 sleeved on the cooling pipe 3. The two are fixed together by welding, thereby reducing the need for welding of one component. step. The number of high-precision welding positions on the rotor shaft is reduced from 2 to 1, and the two welding positions on the cooling pipe 3 require low welding accuracy, which reduces the welding cost. The cooling tube 3 and the fluid distribution member 4 can be made of lighter materials, such as plastic and aluminum alloy, to reduce weight and difficulty in welding. The sealed cavity 5 formed between the cooling pipe 3 and the fluid distribution member 4 is a cavity without cooling liquid, that is, the oil outlet hole of the cooling pipe 3 is arranged outside the sealed cavity 5 . There are two oil outlets on the cooling pipe 3, the first cooling pipe oil outlet 31 and the second cooling pipe oil outlet 32, which are used to guide the cooling liquid into the cooling pipe 3 and the rotor through the oil outlets on the cooling pipe. A cooling channel 6 is formed between the hollow parts 2 of the shaft. The size of the second cooling pipe oil outlet hole 32 on the cooling pipe is larger than the first cooling pipe oil outlet hole 31 in order to evenly distribute the cooling liquid to both ends of the cooling channel 6 . The first rotor shaft oil outlet hole 22 on the rotor shaft is larger than the first rotor shaft oil outlet hole 21 in order to evenly distribute the coolant to both ends of the end winding. The axial end of the cooling pipe 3 opposite to the oil inlet 7 is closed, thereby eliminating the need for the oil plug 9 and avoiding the risk that the oil plug 9 may fall into the motor.

Although possible embodiments are exemplarily described in the above description, it should be understood that there are still numerous variations of the embodiments through combinations of all known technical features and embodiments that are otherwise readily apparent to the skilled person. Furthermore, it should be understood that the exemplary embodiment is merely an example, and such embodiment in no way limits the scope, application, and construction of the invention in any way. The foregoing description is intended to provide skilled persons with technical guidance for transforming at least one exemplary embodiment, in which various changes may be made without departing from the scope of the claims, especially regarding the Changes in the functionality and structure of components.

List of reference signs

1 rotor shaft

2 hollow part

3 cooling pipes

4 fluid distribution parts

5 sealed cavity

6 cooling channels

7 Oil inlet

8 motor rotor

9 oil plug

20 Rotor shaft oil outlet

21 First rotor shaft oil outlet hole

22 Second rotor shaft oil outlet hole

30 Cooling pipe oil outlet

31 First cooling pipe oil outlet

32 Second cooling pipe oil outlet.

Claims (10)

1. A rotor shaft (1) for an electric machine, having a hollow part (2), wherein a cooling tube (3) for conveying a cooling liquid is arranged in the hollow part (2), wherein the cooling tube (3) has cooling tube oil outlet openings (31, 32) in the radial direction of the rotor shaft (1),

the cooling device is characterized in that a fluid distribution member (4) is sleeved on the periphery of the cooling pipe (3), a sealing cavity (5) is formed by the fluid distribution member (4) and the cooling pipe (3), a cooling channel (6) is formed by a gap between the fluid distribution member (4) and the hollow part (2), and the cooling pipe oil outlet holes (31, 32) are formed outside the fluid distribution member (4).

2. Rotor shaft (1) according to claim 1, characterized in that the volume of the sealed cavity (5) is larger than the volume of the cooling channel (6).

3. Rotor shaft (1) according to claim 1, characterized in that the fluid distribution member (4) is fixed on the outer circumference of the cooling tube (3) by welding.

4. Rotor shaft (1) according to claim 1, characterized in that the fluid distribution member (4) is integrally formed with the cooling tube (3).

5. Rotor shaft (1) according to claim 1, characterized in that the fluid distribution member (4) and/or the cooling tube (3) are made of plastic or aluminum alloy.

6. The rotor shaft (1) according to any one of claims 1 to 5, characterized in that the cooling tube (3) has a first cooling tube oil outlet (31) close to an oil inlet (7) of the rotor shaft (1) and a second cooling tube oil outlet (32) remote from the oil inlet (7), wherein the aperture of the first cooling tube oil outlet (31) is smaller than the aperture of the second cooling tube oil outlet (32).

7. The rotor shaft (1) according to claim 6, wherein the first cooling tube oil outlet (31) and the second cooling tube oil outlet (32) are located at both axial ends of the cooling tube (3), respectively, and the fluid distribution member (4) is located between the first cooling tube oil outlet (31) and the second cooling tube oil outlet (32).

8. The rotor shaft (1) according to claim 7, characterized in that the rotor shaft (1) has a first rotor shaft oil outlet (21) close to an oil inlet (7) of the rotor shaft (1) and a second rotor shaft oil outlet (22) remote from the oil inlet (7), wherein the aperture of the first rotor shaft oil outlet (21) is smaller than the aperture of the second rotor shaft oil outlet (22).

9. Rotor shaft (1) according to claim 1, characterized in that the axial end of the cooling tube (3) remote from the oil inlet (7) of the rotor shaft (1) is closed.

10. An electric machine, characterized in that the electric machine has a rotor shaft (1) according to any one of claims 1 to 9.