Patent Application
20240055950
This invention relates to a rotating electrical machine, and in particular to a cooling structure for a rotating electrical machine.
When rotating electrical machines try to achieve high output or torque, their size generally tends to be larger. As the size of rotating electrical machines increases, machinery and equipment in which rotating electrical machines are incorporated also need to be enlarged, so problems such as limited installation space and high cost of machinery and equipment arise.
The expected operation of a rotating electrical machine is obtained by generating torque corresponding to an external load in the drive state.
At this time, copper loss caused by coil energization and iron loss mainly generated inside the iron core due to rotating magnetic flux are generated inside the rotating electrical machine and consumed as heat. The heat generated inside the rotating electrical machine is dissipated from the housing surface by heat conduction.
By quickly removing the exhaust heat of the housing surface, the housing is cooled and the temperature rise inside the rotating electrical machine can be suppressed. Therefore, the size of the rotating electrical machine can be reduced, and the cost can be lowered. In addition, when the same size is used, it is possible to achieve higher output and higher torque. In a permanent magnet type rotating electrical machine, when the temperature rise inside the rotating electrical machine is suppressed, the temperature rise of the permanent magnet is suppressed. Since the resistance to permanent demagnetization of permanent magnets is expanded, it is possible to reduce the thickness of permanent magnets, and further cost reduction can be achieved.
To improve cooling efficiency by exhaust heat from the housing surface, fan driven by other power source is often employed for cooling. The cooling structure is often comprising multiple cooling fans installed on each side of the fan cover that covers the entire side of the rotating electrical machine. Cooling air discharged from the cooling fan passes through the space created between the housing of the rotating electrical machine and the fan cover, quickly exhaust heat from the surface of the housing of the rotating electrical machine, cooling the housing and reducing the temperature rise inside the rotating electrical machine. This cooling process can suppress the temperature rise inside the rotating electrical machine.
Patent document 1 discloses a cooling structure for a rotating electrical machine. In Patent Document 1, multiple cooling fans are arranged in parallel in the axial direction of the rotating electrical machine and installed at a predetermined angle to prevent mutual interference of cooling air discharged from the cooling fans arranged in parallel, thereby improving cooling efficiency.
Patent Documents 1 Patent Publication No. 2015-220854
The structure shown in Patent Literature 1 is designed to prevent mutual interference of cooling air by installing cooling fans at a predetermined angle so that cooling air discharged from multiple cooling fans is directed in the same direction.
However, because of the cooling fans are installed at a predetermined angle, the external dimensions of the rotating electrical machine including the cooling fans become larger, and there is a problem that it is difficult to realize the miniaturization of the rotating electrical machine.
The purpose of the present invention is to provide a rotating electrical machine that improves cooling efficiency by more rapidly exhaust heat from housing surfaces without increasing the external dimensions of the rotating electrical machine.
One preferred example of the invention is a rotating electrical machine comprising: a housing storing a stator and a rotor, a fan cover covers the housing from the outside, an end bracket attached to the axial end face of the housing, a cooling fan installed in the fan cover, wherein output shaft side end face of the fan cover has a convex portion extending in the axial direction, the end bracket on the output shaft side has a concave first exhaust opening part relative to the convex part of the fan cover, the end bracket on the anti-output shaft side has a second exhaust opening part on the opposite side of the first exhaust opening part.
According to the present invention, the cooling efficiency can be improved by rapidly dissipating heat from the housing surface without increasing the external dimensions of the rotating electrical machine.
Example 1 is described with
The output shaft side end face of the fan cover 4 has a convex part extending in the axial direction, and the end bracket 2 on the output shaft side has a concave first exhaust opening part 6 in a position relative to the convex part of the fan cover 4.
On the end bracket 3 on the anti-output shaft side, a second exhaust opening part 6 (left side of
In this example, when the housing of the rotating electrical machine includes four sides and one side is rectangular, the side surfaces of the housing 5 are arranged in a rectangular fan cover 4 for four surfaces at positions close together via a gap. Cold air from the cooling fan 1 can be efficiently circulated in the gap between housing 5 and fan cover 4. If the shape of the outer diameter of housing 5 is cylindrical, a cylindrical fan cover may be used to enclose housing. The cross-sectional shape of the housing is not limited to a square shape but may be any other polygonal shape.
However, since the part corresponding to the concave-shaped exhaust opening part 6 on each end bracket in Example 1 is completely shielded from the wind, the ventilation resistance increases at the blockage 8, so the exhaust does not occur quickly, and housing 5 is not sufficiently cooled in the vicinity of the blockage.
Therefore, the warmed air in the blockage 8 shown in
This example is particularly effective for motors for driving machine tool equipment such as injection molding machines and press machines that require large output and torque.
According to this example, by providing apertures for exhausting cooling air at the axial ends of each side of the rotating electrical machine, cooling efficiency is improved by exhaust heat from the housing surface more quickly, and at the same time, the external dimensions of the rotating electrical machine including the cooling fan, can be avoided.
Example 2 will be described with
Example 2 shows that a partition plate 9 is provided on the inner surface of the fan cover 4 relative to each of a plurality of cooling fans 1 installed on the outer surface of the fan cover 4, so that cooling air 7 discharged from each cooling fan 1 is directed to the exhaust opening part 6 provided on the output shaft side end bracket 2.
In this example, cooling air from cooling fan 1 passes through the gap between fan cover 4 and housing 5, and the flow paths of cooling air from the first cooling fan and the second cooling fan are shown in
Without the partition plate 9, cooling air 7 discharged from multiple cooling fans 1 installed on the outer surface of the fan cover 4 will interfere with each other. Cooling air 7 around the interference zone 10 of cooling air 7 is hard to be discharged to the outside of the rotating electrical machine due to the mutual interference, so the cooling performance of the housing 5 is not sufficient in this area and cooling performance is reduced.
To avoid mutual interference of the cooling air 7, a partition plate 9, which is molded to encourage the exhaust opening part 6 is placed on the inner surface of the fan cover 4 as shown in
By placing the partition plate 9, the cooling air 7 discharged from the cooling fan 1 located on the output shaft side passes near the inner surface of the fan cover 4, and the cooling air 7 discharged from the cooling fan 1 located on the anti-output shaft side passes near the housing surface of the rotating electrical machine.
Cooling air 7 passing through partition 9 merges and is discharged from exhaust opening part 6. In other words, the placement of partition 9 avoids mutual interference of the cooling air 7, enabling the warmed air near the surface of housing 5 to be quickly discharged to the outside of the rotating electrical machine, thereby improving the cooling efficiency.
Example 3 will be described with
In this example, partition plate 9 is arranged for cooling air from cooling fan 1 passes through the gap between fan cover 4 and housing 5 and is divided into cooling air from the first cooling fan located on the output shaft side and cooling air from the second cooling fan located on the anti-output shaft side. By arranging the partition plate 9, mutual interference of cooling air 7 is avoided.
The partition plate 9 in Example 3 is arranged so that the cooling air 7 discharged from the cooling fan 1 located on the anti-output shaft side and control toward the output shaft side is control into the predetermined openings on the output shaft side cut in the four corners of the fan cover 4.
On the other hand, the cooling air 7 discharged from the cooling fan 1 located on the output shaft side and control toward the anti-output shaft side is arranged to be control to the predetermined openings on the four corners of the anti-output shaft side end bracket 3.
Since the warmed air near the interference area 10 of the cooling air 7 is hard to discharge to the outside of the rotating electrical machine, the cooling performance of the housing 5 is not sufficient in this area, and the cooling performance is reduced.
To avoid mutual interference of cooling air 7, partition plate 9 is placed on the inner surface of fan cover 4 as shown in
Cooling air 7 near the interference portion 10 discharged from the cooling fan 1 located on the output shaft side is discharged along the partition plate 9 to the four corner openings of the anti-output shaft side end bracket 3.
On the other hand, the cooling air 7 around the interference area 10 discharged from the cooling fan 1 located on the anti-output shaft side is similarly discharged from the openings in the four corners of the fan cover 4 on the output shaft side.
In other words, the placement of partition plate 9 avoids mutual interference of cooling air 7, enabling warmed air near the housing 5 surface to be quickly discharged to the outside of the rotating electrical machine, thereby improving the cooling efficiency.
According to this example, the height of the cooling air between fan cover 4 and housing 5 can be lowered compared to Example 2, and the outer diameter of the rotating electrical machine can be reduced by that amount.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2021-022169 | Feb 2021 | JP | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2021/046650 | 12/16/2021 | WO |
