CN108462318B - Motor cooling structure, power motor and electric drive system - Google Patents

Abstract

The invention relates to a motor cooling structure, a power motor comprising the same and an electric drive system. The motor cooling structure comprises a rotor liquid cooling structure, the rotor liquid cooling structure comprises a hollow blind hole located in a rotor rotating shaft, a liquid cooling pipeline is arranged in the hollow blind hole, a first end opening of the liquid cooling pipeline extends out of the blind end of the hollow blind hole, a second end opening of the liquid cooling pipeline extends out of the open end of the hollow blind hole, and the hollow blind hole and the liquid cooling pipeline form 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 technical field of power motors; 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, their power motors strive for high power/torque density, high efficiency, and high reliability. During the design, the selection of the electromagnetic load and thermal load of the motor tends to the limit, resulting in a significant increase in the loss and heat generation per unit volume, which has a significant impact on the power and torque density, efficiency, performance of insulating materials, life and reliability of the motor. Impact.

To this end, it is necessary to improve the cooling and heat dissipation of the power motor, reasonably select and arrange the cooling system, avoid local hot spots, and try to fully discharge the heat in the motor. On the premise of ensuring the safe and reliable operation of the motor, fully tap 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, and the heat dissipation of the rotor is usually difficult, and the temperature rise of the rotor is high; Under the condition of high-speed operation, the loss of the bearing itself increases. Considering the heat conduction of the temperature rise of the rotor itself, the temperature of the bearing is too high, and it is easy to cause the bearing to overheat, which seriously affects the life of the bearing.

At present, most of the power motors use the casing liquid cooling method to cool the motor. The casing is usually the outer casing and the inner casing are installed together by shrinking sleeves to form a built-in spiral or S-shaped or other shaped cooling circuit; the stator of the motor Winding generally adopts vacuum dipping technology.

SUMMARY OF THE INVENTION

The object of the present invention is to provide a motor cooling structure that can overcome the aforementioned drawbacks of the prior art.

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

In order to achieve the foregoing 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 the rotor shaft, A liquid cooling pipe is arranged in the hollow blind hole, a first end opening of the liquid cooling pipe extends to the blind end of the hollow blind hole, and a second end opening of the liquid cooling pipe extends to the blind end of the hollow blind hole. The open end of the hollow blind hole, the hollow blind hole and the liquid cooling pipe constitute a liquid cooling flow path of the rotor liquid cooling structure.

Optionally, in the aforementioned motor cooling structure, the end of the liquid cooling pipe having the second end opening is fixed to the motor casing or the motor end cover.

Optionally, in the aforementioned motor cooling structure, the motor cooling structure further includes a stator liquid cooling structure, and the stator liquid cooling structure is in fluid communication with the rotor liquid cooling structure.

Optionally, in the aforementioned motor cooling structure, the stator liquid cooling structure includes a double-spiral liquid cooling circuit at the motor casing.

Optionally, in the aforementioned motor cooling structure, the double-spiral liquid cooling circuit is integrally die-cast in the motor casing.

Optionally, in the aforementioned motor cooling structure, the motor casing includes a nested outer casing and an inner casing, and the double-spiral liquid cooling circuit is formed by the nested outer casing and the inner casing. .

Optionally, in the aforementioned motor cooling structure, the double-spiral liquid cooling circuit has two parallel single-spiral flow paths, and the single-spiral flow paths have a common liquid inlet and different liquid discharges. mouth.

Optionally, in the aforementioned motor cooling structure, the second end opening of the liquid cooling pipe 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 aforementioned motor cooling structure, 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 described above, the motor cooling structure further includes epoxy resin plastic-encapsulated at the stator end windings of the motor, and the epoxy resin is located between the stator end windings and the motor. between the casings.

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

In order to achieve the foregoing object, a third aspect of the present invention provides an electric drive system, wherein the electric drive system includes the motor as described in the foregoing second aspect.

Description of drawings

The disclosure of the present invention will become more apparent with reference to the accompanying drawings. It should be understood that these drawings are for illustrative purposes only, and are not intended to limit the scope of protection of the present invention. In the picture:

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

Figure 2 is a U-shaped motor casing with an integrated double helix liquid cooling circuit of the power motor in Figure 1;

Fig. 3 is the double helix liquid cooling circuit at the motor casing in Fig. 2; And

FIG. 4 is a schematic diagram of the rotor liquid cooling structure of the power motor in FIG. 1 .

Detailed ways

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

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

In the figure, the stator winding 2 is embedded in the stator iron core 3, the stator iron core 3 is assembled on the motor casing 1 by shrink fit, and the motor end cover 5 and the motor casing 1 are connected together by bolts. The motor casing 1 may have a built-in stator liquid cooling structure. When the motor is running, the coolant circulates in the liquid cooling structure of the stator to remove the heat from the stator of the motor. The cooling liquid here can be cooling water or other common liquid cooling medium.

In addition, the end windings of the stator core 3 can be plastic-sealed by vacuum casting epoxy resin 4 . As shown in the figure, the epoxy resin 4 can be located between the stator end winding and the motor casing, which significantly improves the heat dissipation performance of the motor stator end winding while ensuring the insulation performance of the stator winding.

In the figure, the rotor core 6 can be installed on the rotor shaft 8 by interference fit, and the rotor end rings 7a and 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 provided on the outer sides of the first bearing 9a and the second bearing 9b, respectively. A hollow blind hole 18 is arranged in the rotor shaft 8, and a liquid cooling pipe 11 is arranged in the hollow blind hole 18. It can be understood that the cooling liquid can flow in from the liquid cooling pipe 11, flow out from the hollow blind hole 18, and can also flow from the hollow blind hole. 18 flows into and flows out from the liquid cooling pipe 11 to realize the cooling of the motor rotor.

According to FIG. 1 , the end of the liquid cooling pipe 11 with the first end opening 11 a is suspended in the hollow blind hole 18 ; and the end with the second end opening 11 b is fixed to the motor casing 1 or the motor end cover. In order to ensure that the cooling liquid 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 .

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

The stator liquid cooling structure of the power motor may be located at the motor housing. The stator liquid cooling structure in the illustrated embodiment has a double helix liquid cooling circuit. It can be understood that the double helix liquid cooling circuit can be formed inside or outside the motor casing or built into the motor integrated casing. For example, in alternative embodiments, the double helix liquid cooling structure may be cast directly within the motor housing; or the motor housing may include a nested outer and inner casing from which the double helix liquid cooling circuit may be formed. The outer shell and the inner shell are formed in cooperation. Specifically, the outer shell and the inner shell can be installed with a shrink sleeve and fixed by welding at both ends. Preferably, the stator liquid-cooling structure may be in fluid communication with the rotor liquid-cooling structure; detailed description will be given below in conjunction with the stator liquid-cooling structure and the rotor liquid-cooling structure.

FIG. 3 shows the double-spiral liquid cooling circuit at the motor casing in FIG. 2 .

It can be seen from the figure that the double-spiral liquid cooling circuit can have two parallel single-spiral flow paths, and the single-spiral flow paths have a common liquid inlet 13 and different liquid discharge ports 14 and 15 . It can be seen that the cooling liquid in the double-spiral liquid cooling circuit will flow into the liquid inlet 13, and then flow along the two single-spiral flow paths in two separate paths to cool the motor stator, and then drain the liquid from the first single-spiral flow path. The port 15 and the drain port 14 of the second single helical flow path flow out.

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

FIG. 4 is a schematic diagram of the rotor liquid cooling structure of the power motor in FIG. 1 .

As can be seen from the figure, the rotor liquid cooling structure includes a hollow blind hole 18 located in the rotor shaft 8, a liquid cooling pipe 11 is arranged in the hollow blind hole 18, and an annular chamber suitable for cooling liquid is formed between the two. flow past. The first end opening 11 a of the liquid cooling pipe 11 extends to the blind end of the hollow blind hole 18 , and the second end opening 11 b of the liquid cooling pipe 11 extends to the open end of the hollow blind hole 18 . The hollow blind hole 18 and the liquid cooling pipe 11 constitute the liquid cooling flow path of the rotor liquid cooling structure. In addition, the rotor liquid cooling structure further includes a liquid inlet port 16 and a liquid outlet port 17 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 discussed, the rotor liquid cooling structure may be in fluid communication with the stator liquid cooling structure. For example, the second end opening 11b of the liquid cooling pipe 11 may be connected to the liquid outlet 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 cooling liquid can enter into the rotor shaft 8 through the liquid inlet 16 of the liquid cooling pipe 11 in the rotor shaft 8 through the liquid outlet 14 or 15 of the first single spiral flow path on the motor casing 1 . The liquid cooling pipe 11 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 may be connected to the liquid discharge port 14 or 15 of one of the two single-spiral flow paths via the liquid inlet port 16 of the rotor liquid cooling structure. In this case, the cooling liquid can also enter the rotor shaft 8 through the liquid outlet 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 into the annular chamber, and then flows out through the annular chamber and the liquid cooling pipeline 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 manners can realize different cooling liquid 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 aforementioned motor cooling structure. It is conceivable that such a motor and electric drive system can be used to drive new energy vehicles such as new energy vehicles.

Those skilled in the art can understand that the present invention adopts the liquid cooling method of the motor casing of the double helix structure to cool and dissipate the heat of the stator of the motor, and pours epoxy resin at the stator end winding for plastic sealing, so as to further improve the stator end winding. The heat dissipation of the motor stator makes the heat on the stator of the motor well diffused, which is of great significance for improving the life of the insulation material of the motor; at the same time, in order to coordinate the design analysis and avoid the motor rotor overheating or the bearing overheating, the present invention adopts the rotor The liquid-cooled structure, in coordination 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 content in the above description. Those skilled in the art can make various deformations and modifications to the above-mentioned embodiments without departing from the technical idea of the present invention, and these deformations and modifications should belong to within the scope of the present invention.

Claims (7)

1. A motor cooling structure, characterized in that the motor cooling structure includes a rotor liquid cooling structure, and the rotor liquid cooling structure includes a hollow blind hole located in the rotor shaft, and a hollow blind hole is provided in the hollow blind hole. a liquid cooling pipe, the first end opening of the liquid cooling pipe extends to the blind end of the hollow blind hole, the second end opening of the liquid cooling pipe extends to the open end of the hollow blind hole, the The hollow blind hole and the liquid cooling pipe constitute a liquid cooling flow path of the rotor liquid cooling structure, wherein the motor cooling structure further includes a stator liquid cooling structure, and the stator liquid cooling structure includes a double helix at the motor casing A liquid cooling circuit, wherein the double helical liquid cooling circuit has two parallel single helical flow paths, and the single helical flow paths have a common liquid inlet and different liquid discharge ports, and the stator liquid cooling structure is identical to that of the liquid cooling circuit. The rotor liquid cooling structure realizes fluid communication in the following two ways: i The opening of the second end of the liquid cooling pipe is connected to the liquid discharge port of one of the two single-spiral flow paths through the liquid inlet of the rotor liquid cooling structure, and the other liquid discharge port directly passes through the motor casing Outflow, so that the cooling liquid enters the liquid cooling pipe in the rotor shaft through the liquid outlet of one of the two single spiral flow paths through the liquid inlet of the liquid cooling pipe in the rotor shaft, and then passes through the liquid cooling pipe and the liquid cooling pipe. Outflow from the annular chamber in the rotor shaft and finally through the liquid outlet of the rotor liquid cooling structure; or ii The open end of the hollow blind hole is connected to the liquid discharge port of one of the two single-spiral flow paths through the liquid inlet of the rotor liquid cooling structure, and the other liquid discharge port directly passes through the motor casing to the outside outflow, so that the cooling liquid enters the annular chamber in the rotor shaft through the liquid outlet of one of the two single spiral flow paths through the liquid inlet of the liquid cooling pipe in the rotor shaft, and then passes through the annular chamber and the liquid cooling pipe. It flows out, and finally flows out through the liquid outlet of the liquid cooling structure of the rotor. 2 . The motor cooling structure according to claim 1 , wherein one end of the liquid cooling pipe with the second end opening is fixed to the motor casing or the motor end cover. 3 . 3 . The motor cooling structure of claim 1 , wherein the double helix liquid cooling circuit is integrally die-cast in the motor casing. 4 . 4 . The motor cooling structure of claim 3 , wherein the motor housing comprises a nested outer shell and an inner shell, and the double-spiral liquid cooling circuit is formed by the nested outer shell and the inner shell. 5 . . 5. The motor cooling structure of any one of claims 1 to 4, wherein the motor cooling structure further comprises epoxy resin molded at the stator end windings of the motor, the epoxy resin being located on the Between the stator end windings and the motor casing. 6. A power motor, characterized in that the power motor comprises the motor cooling structure according to any one of the preceding claims 1 to 5. 7. An electric drive system, characterized in that the electric drive system comprises the motor of claim 6.

Images