JP4882346B2 - Cooling device for rotating electrical machine with permanent magnet - Google Patents

Description

  The present invention relates to a cooling device for a rotating electric machine that includes a permanent magnet on a rotor side, and a stator side including a winding and an iron core.

A rotary electric machine is mainly composed of a stator and a rotor. In many AC rotating electrical machines, a stator core and a stator winding are installed on the stator side, and a rotor core and a field winding are installed on the rotor side. As a result of the alternating current being passed through the stator winding, an alternating magnetic field is generated in the stator core. Therefore, on the stator side, in addition to the Joule loss due to the stator winding current, iron loss (hysteresis in the stator core) Loss and eddy current loss).
On the other hand, on the rotor side, the current flowing through the field winding is usually a direct current, and the rotor rotates in synchronization with the rotational speed of the rotating magnetic field generated by the stator winding current on the stator side. The magnetic flux passing through the iron core is considered to be almost direct current. Therefore, the iron loss on the rotor side is smaller than the Joule loss due to the field winding current.
Since the magnetic field generated by the field winding current is a DC magnetic field, it can be replaced with a permanent magnet. A permanent magnet rotating electric machine that uses a permanent magnet instead of the rotor field winding does not require excitation by the field winding, so there is no Joule heat generation in the field winding. Therefore, it is not necessary to cool the rotor side specially, the burden on the entire cooling device can be reduced, and the size can be reduced. Therefore, the rotor side is often used for ships where the space for installing the motor is limited.

Conventionally, a cooling device for a rotating electric machine of this type has been used by a stirring fan attached to a rotor as disclosed in Patent Document 1. FIG. 4 shows an axial section of a permanent magnet rotary electric machine that is cooled by a stirring fan. That is, in FIG. 4, the stirring fan 8 is a projecting piece that is rotatably attached to the stator frame via a bearing 12 and protrudes from the axial end of the rotor 1 on which the permanent magnet 2 is mounted on the outer peripheral portion. As the rotor 1 rotates, the air layer in the rotating electrical machine is agitated, and by this agitating action, the outside air circulates inside and outside through the ventilation holes 13 provided in the stator frame, thereby cooling the winding and the iron core. Is called.
JP 2000-32709 A

In the cooling device of the conventional structure, cooling is performed by stirring the air in the rotating electric machine with a stirring fan, but in this device, it is not possible to control the designation of the flow path of the air flow or the distribution of the flow rate, There is a drawback in that a sufficient air flow cannot be supplied to a portion that requires cooling, such as a portion having a high heat generation density or a coil end of a stator coil that must be cooled only by an air flow.
Further, since the heat generated in the rotary electric machine is generated by the air flow flowing inside and outside, it is necessary to provide a ventilation hole in the housing, which cannot be adopted for a rotary electric machine that requires a sealed structure. There is also.
An object of the present invention is to solve the above-mentioned problems and to provide a cooling device that improves the heat dissipation efficiency of heat generated in a rotating electric machine.

For this reason, in the present invention, in a rotating electric machine comprising a rotor having a permanent magnet, an iron core and a stator coil, and a stator attached to the frame via a core ring, the axial end of the rotor A stirrer fan, a first partition provided close to the end of the stator coil, and a second partition provided at the end of the stirrer in the axial direction. Circulating the gaps at the ends, the air cooling section, and the first and second partitions, heat is exchanged with the cooling air.
As another means, the air cooling section has a structure including a water chamber and cooling fins provided at an end portion in the axial direction of the core ring through which cooling water is passed through the core ring that supports the stator core. .

In the present invention, the air flow path is set so that the agitated cooling air circulates around the partition, and an air cooling unit is provided at the end on the stator side to perform heat exchange with the cooling air. Therefore, while the conventional cooling device generates an air flow only around the stirring fan, it is possible to supply sufficient cooling air to the coil end portion of the stator coil, which tends to be particularly bad in cooling conditions, and to cool the cooling fan. Air is heat-exchanged in the air cooling section and dissipates heat to the stator side, so that the cooling function can be achieved only by air circulation even in the rotary electric machine having a sealed structure.
When the number of coils of the stator coil is large and the interval between adjacent coils is narrow, the ventilation resistance at the coil end portion becomes large and the cooling air becomes difficult to pass. Therefore, the cooling air circulates around the stirring fan in a short circuit. The ratio is high. In the present invention, in addition to the partition near the end of the stator coil, by providing partitions at both axial ends of the stirring fan of the rotor, it is possible to prevent the cooling air from circulating in a short circuit only around the stirring fan. The amount of cooling air passing through the coil end portion can be secured.
In addition, by using water cooling on the stator side and water chambers and cooling fins provided at both ends in the axial direction of the water cooling device as air cooling units, the cooling performance can be improved, and the overall size of the rotating electric machine can be reduced. Can be planned.

  Next, specific embodiments of the cooling device for a rotating electrical machine according to the present invention will be described with reference to the drawings.

FIG. 1 is an axial cross-sectional view of a permanent magnet rotating electric machine equipped with a cooling device for explaining the present invention. In FIG. 1, a rotor 1 having a permanent magnet 2 attached to its surface is fixed to a rotating shaft 11 and is rotatably supported by a stator frame via a bearing 12. A stator core 3 and a stator winding 4 are arranged opposite to the permanent magnet 2, and these are fixed to the stator frame via a core ring 5.
1 includes a stirring fan 8 provided at both axial ends of the rotor 1, cooling fins 7 provided at both axial ends of the core ring 5 as air cooling units, and a stator winding. It consists of the partition 9 installed in the vicinity of the coil end 10 of this.
The cooling fin 7 does not prevent the airflow from flowing in the radial direction, and heat exchange with the airflow must be sufficiently performed. In this embodiment, a plurality of metal thin plates and a gap in the circumferential direction are formed. Provided and arranged in a radial pattern, arranged on the entire circumference. Arranging a large number of cylindrical protrusions as another structure also exhibits the same effect.

The shape of the partition 9 is a disk shape arranged at right angles to the rotor shaft in FIG. 1, but if it has a function of preventing the air flow from flowing in the axial direction in the vicinity of the coil end, The shape, for example, a combination of a plurality of fan-shaped or rectangular plates may be used.
Next, the operation of the cooling device shown in FIG. 1 will be described. When the rotor 1 rotates, the air is stirred around the stirring fan 8. However, since the partition 9 exists, the air flow passes through the coil end 10 and the coil gap, and then contacts the cooling fin 7. It circulates in the normal route which returns to the stirring fan 8 through. In this circulation, the air flow cools the coil end 1 0 and the temperature rises, but since the heat is exchanged by the cooling fins 7, it returns to the original temperature here. Therefore, this air flow can continuously contribute to cooling the coil end after returning to the stirring fan 8. Since it is not necessary to supply new air from the outside, it is effective even in the case of a rotary electric machine having a sealed structure. Eventually, the heat generated in the coil end portion is transmitted to the stator side through the core ring 5 and is radiated from the stator frame to the outside air.

FIG. 2 is a sectional view in the axial direction of a permanent magnet rotating electric machine provided with another cooling device. In this structure, cooling water is passed through a core ring 5 that supports the stator core 3, and water chambers 6 and cooling fins 7 provided at both ends in the axial direction of the core ring are used as air cooling units. Even in the case of this cooling device, the air flow stirred by the stirring fan 8 circulates behind the coil ends 10, the cooling fins 7, and the partitions 9 as in the first embodiment. The heat generated in the coil end is transferred to the cooling water in the core ring 5 through the cooling fins 7 and the water chamber 6, and is discharged to the outside using a water tank, pump, and cooler (not shown). By adopting the water cooling method, not only the coil end 10 but also the cooling performance of the stator core 3 and the stator coil 4 can be improved, and as a result, the entire rotating electrical machine can be reduced in size.

FIG. 3 is an axial cross-sectional view of a permanent magnet rotating electric machine equipped with the cooling device of the present invention . In addition to the partition A9a arranged on the stator side, partitions B9b are also provided at both axial ends of the stirring fan 8 of the rotor 1. When the number of coils of the stator winding 4 is large and the conductor interval between the coil ends 10 is narrow, the flow resistance becomes large and the agitated air flow becomes difficult to pass through the conductor gap of the coil end 10, and only around the stirring fan 8. As a result, the amount of air circulating in a short circuit increases. The partitions B9b at both axial ends of the agitating fan 8 together with the stator-side partition A9a secure the amount of air passing through the conductor gap of the coil end 10 by increasing the short-circuit flow path resistance.

Axial sectional view of a permanent magnet rotary electric machine for explaining the present invention Axial cross-sectional view of a permanent magnet rotating electrical machine with other cooling devices Axial sectional view of a permanent magnet rotary electric machine equipped with a cooling device of the present invention Axial sectional view of a permanent magnet rotary electric machine with a conventional cooling device

DESCRIPTION OF SYMBOLS 1 Rotor 2 Permanent magnet 3 Stator iron core 4 Stator winding 5 Core ring 6 Water chamber 7 Cooling fin 8 Stirring fan 9 Partition 9a Partition A
9b Partition B
10 Coil end 11 Rotating shaft 12 Bearing 13 Ventilation hole

Claims (2)

In a rotating electric machine composed of a rotor having a permanent magnet, a stator that is constituted by an iron core and a stator coil, and is attached to a frame via a core ring,
A stirring fan provided in the axial end of the rotor, a first partition provided in proximity set to said stator coil end portion, and a second partition provided in the axial end portion of the agitation fan, wherein An air cooling section provided at the end of the core ring, and circulating the air flow by the stirring fan through the clearance of the end of the stator coil, the air cooling section, and the back sides of the first and second partitions. A cooling device for a rotating electrical machine comprising a permanent magnet.   2. The cooling device according to claim 1, wherein the air cooling portion includes a water chamber and a cooling fin provided at an end portion in the axial direction of the core ring, allowing cooling water to flow through the core ring. Cooling device for rotating electrical machines with permanent magnets.

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