WO2018153001A1 - Motor cooling structure, power motor and electric drive system - Google Patents

Abstract

A motor cooling structure and a power motor and an electric drive system comprising same. The motor cooling structure comprises a rotor liquid cooling structure; the rotor liquid cooling structure comprises a hollow blind hole (18) located in a rotor rotation shaft (8); a liquid cooling pipeline (11) is disposed in the hollow blind hole; a first end opening (11a) of the liquid cooling pipeline protrudes to the blind end of the hollow blind hole, and a second end opening (11b) of the liquid cooling pipeline protrudes to the opening end of the hollow blind hole; and the hollow blind hole and the liquid cooling pipeline constitute a liquid cooling flow path of the rotor liquid cooling structure.

Description

Motor cooling structure, power motor and electric drive system Technical field

The present invention relates to the field of power motor technology; in particular, the present invention relates to a motor cooling structure, a power motor, and an electric drive system.

Background technique

Taking electric vehicles as an example, its power motors are striving for high power/torque density, high efficiency, and high reliability. At the time of design, the selection of electromagnetic load and thermal load of the motor tends to the limit, resulting in a significant increase in loss per unit volume and heat generation, which significantly affects the power and torque density of the motor, efficiency, performance of the insulating material, and lifetime and reliability. Impact.

To this end, it is necessary to improve the cooling and cooling of the power motor, reasonably select and arrange the cooling system, avoid local hot spots, and try to fully discharge the heat inside the motor. Under the premise of ensuring safe and reliable operation of the motor, fully exploit the potential of the motor to maximize the performance of the motor.

For induction motors, due to the induction of current on the rotor, a large amount of heat is generated on the rotor. Usually, the heat dissipation of the rotor is difficult, and the temperature rise of the rotor is high. At the same time, the rotational speed of the power motor is usually very high, up to 15000 rpm. Under high-speed operating conditions, the bearing's own loss increases. Considering the heat transfer of the rotor itself, the temperature of the bearing is too high, and the bearing overheating is easily generated, which seriously affects the bearing life.

At present, most of the power motors use the liquid cooling method of the casing to cool the motor. The casing is usually installed with the outer casing and the inner casing through a hot sleeve to form a built-in spiral or S-shaped or other shaped cooling circuit; the stator of the motor Vacuum dipping technology is commonly used for windings.

Summary of the invention

It is an object of the present invention to provide a motor cooling structure that overcomes the aforementioned drawbacks of the prior art.

Further, it is an object of the present invention to provide a power motor and an electric drive system including the aforementioned motor cooling structure.

In order to achieve the aforementioned object, a first aspect of the present invention provides a motor cooling structure, wherein the motor cooling structure includes a rotor liquid cooling structure, and the rotor liquid cooling structure includes a hollow blind hole located in a rotor shaft. a liquid cooling pipe is disposed in the hollow blind hole, a first end opening of the liquid cooling pipe protrudes to a blind end of the hollow blind hole, and a second end opening of the liquid cooling pipe protrudes to the Hollow blind hole The open end, the hollow blind hole and the liquid cooling pipe constitute a liquid cooling flow path of the rotor liquid cooling structure.

Optionally, in the motor cooling structure as described above, one end of the liquid-cooled pipe having the second end opening is fixed to the motor casing or the motor end cover.

Optionally, in the motor cooling structure as described above, the motor cooling structure further includes a stator liquid cooling structure, the stator liquid cooling structure being in fluid communication with the rotor liquid cooling structure.

Optionally, in the motor cooling structure as described above, the stator liquid cooling structure comprises a double helix liquid cooling circuit at the motor casing.

Optionally, in the motor cooling structure as described above, the double spiral liquid cold circuit is integrally die-cast in the motor casing.

Optionally, in the motor cooling structure as described above, the motor casing comprises a nested outer casing and an inner casing, and the double spiral liquid cold circuit is formed by the nesting of the outer casing and the inner casing. .

Optionally, in the motor cooling structure as described above, the double spiral liquid cold circuit has two parallel single spiral flow paths, and the single spiral flow path has a common liquid inlet and different drainage mouth.

Optionally, in the motor cooling structure as described above, the second end opening of the liquid cooling duct is connected to the row of one of the two single spiral flow paths via the liquid inlet of the rotor liquid cooling structure Liquid port.

Optionally, in the motor cooling structure as described above, the open end of the hollow blind hole is connected to the liquid discharge port of one of the two single spiral flow paths via the liquid inlet of the rotor liquid cooling structure. .

Optionally, in the motor cooling structure as described above, the motor cooling structure further comprises an epoxy resin molded at a stator end winding of the motor, the epoxy being located at the stator end winding and the motor Between the casings.

In order to achieve the aforementioned object, a second aspect of the invention provides a power motor, wherein the power motor includes the motor cooling structure according to any of the preceding first aspects.

In order to achieve the aforementioned object, a third aspect of the invention provides an electric drive system, wherein the electric drive system comprises the electric machine as described in the aforementioned second aspect.

DRAWINGS

The disclosure of the present invention will become more apparent from the drawings. It is to be understood that the appended drawings are not intended to In the picture:

1 is a schematic cross-sectional view showing an embodiment of a power motor according to the present invention;

2 is a U-shaped motor casing with an integrated double-spiral liquid cooling circuit of the power motor of FIG. 1;

Figure 3 is a double spiral liquid cooling circuit at the motor casing of Figure 2;

4 is a schematic view showing a liquid cooling structure of a rotor of the power motor of FIG. 1.

detailed description

Specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. In the respective drawings, the same reference numerals indicate the same or corresponding technical features.

1 is a schematic cross-sectional view of an embodiment of a power motor in accordance with the present invention. As can be seen from the figure, the power motor includes a motor casing 1, a stator winding 2, a stator core 3, a motor end cover 5, a rotor core 6, and the like.

In the figure, the stator winding 2 is embedded in the stator core 3, and the stator core 3 is thermally fitted to the motor casing 1, and the motor end cover 5 is connected to the motor casing 1 by bolts. The motor casing 1 can have a stator liquid cooling structure. When the motor is running, the coolant circulates in the stator liquid cooling structure, taking away the heat at the stator of the motor. The coolant here may be cooling water or other commonly used liquid cooling medium.

In addition, the end winding of the stator core 3 can be molded by vacuum casting epoxy resin 4. As shown in the figure, the epoxy resin 4 can be between the stator end winding and the motor casing, and the heat dissipation performance of the stator end winding of the motor is significantly improved while ensuring the insulation performance of the stator winding.

In the figure, the rotor core 6 can be mounted on the rotor shaft 8 by an interference fit, and the rotor end rings 7a, 7b are located on both sides of the rotor core 6. The rotor shaft 8 is supported on the motor casing 1 and the end cover 5 through the first bearing 9a and the second bearing 9b at both ends. O-rings 10a and 10b are respectively disposed outside the first bearing 9a and the second bearing 9b. A hollow blind hole 18 is disposed in the rotor shaft 8, and a liquid cooling pipe 11 is disposed in the hollow blind hole 18. It can be understood that the coolant can flow from the liquid cooling pipe 11 and flow out from the hollow blind hole 18, or can be from the hollow blind hole. 18 flows in and out of the liquid cooling pipe 11 to cool the rotor of the motor.

According to Fig. 1, one end of the liquid-cooled pipe 11 having the first end opening 11a is suspended in the hollow blind hole 18, and the one end having the second end opening 11b is fixed to the motor casing 1 or the motor end cover. In order to ensure that the coolant of the rotor liquid cooling structure does not enter the interior of the motor, a dynamic seal 12 may be provided at the end of the rotor shaft 8.

2 is a motor casing 1 of the power motor of FIG. 1 with an integrated stator liquid cooling structure. The motor casing 1 may have a U-shaped structure formed by integral die casting. It can be understood that the one-piece liquid-cooled casing structure is simpler and more reliable.

The stator liquid cooling structure of the power motor can be located at the motor casing. In the illustrated embodiment The stator liquid cooling structure has a double spiral liquid cooling circuit. It can be understood that the double spiral liquid cold circuit can be formed inside or outside the motor casing or built in the motor-integrated casing. For example, in an alternative embodiment, the double helix liquid cold structure may be directly cast into the motor casing; or the motor casing may include a nested outer casing and an inner casing, and the double helix liquid cold circuit may be nested by the nested The outer casing and the inner casing are formed in cooperation. Specifically, the outer casing and the inner casing may be mounted by a heat jacket and welded at both ends. Preferably, the stator liquid cooling structure may be in fluid communication with the rotor liquid cooling structure; a description will be specifically made below in connection with the stator liquid cooling structure and the rotor liquid cooling structure.

Figure 3 is a double spiral liquid cooling circuit at the motor casing of Figure 2.

As can be seen from the figure, the double helix liquid cold circuit can have two parallel single spiral flow paths, and the single spiral flow path has a common liquid inlet port 13 and different liquid discharge ports 14, 15. It can be seen that the coolant in the double spiral liquid cooling circuit will flow in from the liquid inlet port 13, and then flow in two single spiral flow paths in two ways to cool the motor stator and then drain from the first single spiral flow path. The liquid discharge port 14 of the port 15 and the second single spiral flow path flows out.

As described above, the stator liquid cooling structure can be in fluid communication with the rotor liquid cooling structure. In an alternative embodiment, the liquid discharge port 15 of the double spiral liquid cooling circuit of the stator liquid cooling structure may be directly connected to the liquid inlet of the rotor liquid cooling structure to cool the rotor; and the liquid discharge port 14 may directly pass through The motor casing 1 flows outward. Correspondingly, the liquid discharge port 14 can be directly connected to the liquid inlet of the rotor liquid cooling structure to cool the rotor, and the liquid discharge port 15 directly flows out through the motor casing 1.

4 is a schematic view showing a liquid cooling structure of a rotor of the power motor of FIG. 1.

As can be seen from the figure, the rotor liquid cooling structure comprises a hollow blind hole 18 in the rotor shaft 8, and a liquid cooling pipe 11 is arranged in the hollow blind hole 18, and an annular chamber is formed between them to be suitable for the cooling liquid. flow past. The first end opening 11a of the liquid cooling duct 11 projects to the blind end of the hollow blind hole 18, and the second end opening 11b of the liquid cooling duct 11 projects to the open end of the hollow blind hole 18. The hollow blind hole 18 and the liquid cooling pipe 11 constitute a liquid cooling flow path of the rotor liquid cooling structure. Further, the rotor liquid cooling structure further includes a liquid inlet port 16 and a liquid outlet port 17 which are respectively connected to the first end opening 11a of the liquid cooling pipe and the open end of the hollow blind hole 18.

As previously described, the rotor liquid cooling structure can be in fluid communication with the stator liquid cooling structure. For example, the second end opening 11b of the liquid cooling duct 11 may be connected to the liquid discharge port 14 or 15 of one of the two single spiral flow paths via the liquid inlet 16 of the rotor liquid cooling structure. In this case, the coolant can be introduced through the liquid discharge port 14 or 15 of the first single spiral flow path on the motor casing 1 through the liquid inlet 16 of the liquid cooling pipe 11 in the rotor shaft 8. It enters the liquid-cooled pipe 11 in the rotor shaft 8, and then flows out through the liquid-cooling pipe 11 and the annular chamber in the rotor shaft 8, and finally flows out through the liquid outlet 17 of the rotor liquid-cooling structure 11. For another example, the open end of the hollow blind hole 18 can be connected to the liquid discharge port 14 or 15 of one of the two single spiral flow paths via the liquid inlet 16 of the rotor liquid cooling structure. In this case, the coolant can also enter the rotor shaft 8 via the liquid discharge port 14 or 15 of the first single spiral flow path on the motor casing 1 through the liquid inlet 16 of the liquid cooling pipe 11 in the rotor shaft 8. The annular chamber is then flowed out through the annular chamber and the liquid cooling conduit 11, and finally flows out through the liquid outlet 17 of the rotor liquid cooling structure. It can be understood that the above two different connection modes can realize different coolant flow directions in the rotor liquid cooling structure.

From the above description, those skilled in the art can obtain a power motor and an electric drive system including the motor cooling structure as described above. It is envisaged that such motors and electric drive systems can be used to drive new energy vehicles such as new energy vehicles.

Those skilled in the art can understand that the present invention uses a double-helical structure of the motor casing to cool and cool the stator of the motor, and casts an epoxy resin at the end winding of the stator to plastically seal, further improving the stator end winding. The heat dissipation makes the heat on the stator of the motor get well, which is of great significance for improving the life of the insulating material of the motor. At the same time, in order to coordinate the design analysis and avoid the overheating of the rotor of the motor or the overheating of the bearing, the present invention adopts the rotor. The liquid-cooled structure, in conjunction with the electromagnetic and thermal design of the motor, avoids local weak links and helps to improve the power and torque density, life and reliability of the motor, which is of great significance.

The technical scope of the present invention is not limited to the above description, and various modifications and changes can be made to the above-described embodiments without departing from the technical idea of the present invention. Within the scope of the invention.

Claims (12)

An electric motor cooling structure, characterized in that the motor cooling structure comprises a rotor liquid cooling structure, and the rotor liquid cooling structure comprises a hollow blind hole in the rotor rotating shaft, and liquid cooling is arranged in the hollow blind hole a pipe, a first end opening of the liquid cooling pipe protrudes to a blind end of the hollow blind hole, and a second end opening of the liquid cooling pipe protrudes to an open end of the hollow blind hole, the hollow blind The hole and the liquid cooling pipe constitute a liquid cooling flow path of the rotor liquid cooling structure. The motor cooling structure according to claim 1, wherein one end of said liquid-cooled pipe having said second end opening is fixed to a motor casing or a motor end cover. The motor cooling structure according to claim 1 or 2, wherein said motor cooling structure further comprises a stator liquid cooling structure, said stator liquid cooling structure being in fluid communication with said rotor liquid cooling structure. The motor cooling structure of claim 3 wherein said stator liquid cooling structure comprises a double helix liquid cooling circuit at the motor casing. The motor cooling structure according to claim 4, wherein said double spiral liquid cold circuit is integrally die-cast in said motor casing. The motor cooling structure according to claim 5, wherein said motor casing comprises a nested outer casing and an inner casing, and said double spiral liquid cold circuit is formed by a nested said outer casing and said inner casing. The motor cooling structure according to any one of claims 4 to 6, wherein the double helix liquid cold circuit has two parallel single spiral flow paths, and the single spiral flow path has a common liquid inlet and Different drains. The motor cooling structure according to claim 7, wherein the second end opening of the liquid cooling duct is connected to the liquid discharge port of one of the two single spiral flow paths via an inlet of the rotor liquid cooling structure . The motor cooling structure according to claim 7, wherein the open end of the hollow blind hole is connected to the liquid discharge port of one of the two single spiral flow paths via a liquid inlet of the rotor liquid cooling structure. The motor cooling structure according to any one of claims 1 to 9, wherein the motor cooling structure further comprises an epoxy resin molded at a stator end winding of the motor, the epoxy being located at the stator end Between the winding and the motor casing. A power motor, characterized in that the power motor comprises a motor cooling structure according to any of the preceding claims 1 to 10. An electric drive system, characterized in that the electric drive system comprises the electric machine according to claim 11.

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