JP6268750B2 - Rotating electric machine - Google Patents

Description

  The present invention relates to a rotating electrical machine having a cooling structure.

  In a rotating machine having a rotor and a stator, a cooling structure for cooling the rotating machine heated by the rotation of the rotor is provided.

  A rotor iron core composed of magnetic steel sheets arranged coaxially with the rotor shaft, and the rotor shaft to compress and hold the rotor iron core from both sides in the axial direction and to transmit torque between the rotor iron core and the rotor shaft. Rotating machine comprising: an end plate fixed to the rotor; a cooling passage defined between the outer periphery of the rotor shaft and the inner periphery of the rotor core; and a passage for introducing refrigerant into the cooling passage through the rotor shaft Is disclosed (Patent Document 1).

  In a rotating machine having a rotor arranged with a gap inside a stator and having a permanent magnet inserted and fixed in a magnet insertion hole extending in the rotor axial direction provided in the rotor iron core, the permanent magnet with respect to the rotation center of the rotor A cooling passage is formed on the inner side surface of the permanent magnet to guide the refrigerant along the magnet insertion hole. The cross-sectional shape of the cooling passage is convex with a vertex toward the rotation center. A rotating machine having a shape is disclosed (Patent Document 2).

  An air flow that includes a stator housed in a case and a rotor whose outer peripheral surface faces the inner peripheral surface of the stator via a gap, and generates an air flow toward the axially open end in the gap between the rotor and the stator. A rotating machine including a generator is disclosed (Patent Document 3).

JP 2012-165488 A JP 2002-345188 A JP 2003-250248 A

  By the way, only the refrigerant flow path formed at both ends of the rotor in the axial direction at the time of cooling only cools the magnet end face, and the thermal conductivity of the magnet is small. The effect is small for cooling the center of the direction.

  When flowing a refrigerant through the flow path, it is necessary to improve the flow rate of the refrigerant in the flow path in order to ensure sufficient cooling performance. At that time, in order to secure a heat transfer area for the magnet, a certain amount of flow path cross-sectional area is required, and as many flow paths as the number of magnets are required. As a result, the supply amount of the refrigerant becomes enormous. On the other hand, since the flow rate of the refrigerant in the rotating machine is usually about 10 L / min, it is difficult to obtain a sufficient cooling effect with this flow rate.

  Moreover, sufficient cooling effect cannot be obtained by cooling using an air stream.

  The present invention is a rotating electrical machine comprising a stator and a rotor that rotates relative to the stator, wherein oil and air are simultaneously supplied to a gap between the stator and the rotor to provide the gap. Is a rotating electrical machine characterized by using a refrigerant flow path.

  Here, it is preferable that the oil and the air are in a gas / liquid two-phase flow in the gap.

  Also, an oil supply path for supplying oil to the gap via a flow path passing through the center of the rotor shaft connected to the rotor, and an air supply path for supplying air to the gap from the stator side are provided. Is preferred.

  Also, an air supply path for supplying air to the gap via a flow path passing through the center of the rotor shaft connected to the rotor, and an oil supply path for supplying oil to the gap from the stator side are provided. Is preferred.

  Further, it is preferable that the oil supply path has a plurality of flow paths connected to the gap.

  It is preferable that an oil supply path for supplying oil to the gap by nozzle injection and an air supply path for supplying air to the gap from the stator side are preferably provided.

  In addition, it is preferable that an oil storage portion that stores the oil is provided at an end portion in the axial direction of the rotor, and the oil is supplied from the oil storage portion to the gap.

  In addition, it is preferable that the air supply path has a plurality of flow paths connected to the gap.

  Moreover, it is preferable that the void ratio (air volume / (oil volume + air volume)) between the oil and the air is 0.05 or more and 0.9 or less.

  It is preferable that a temperature sensor for measuring the temperature of the rotor is provided, and the supply amount of at least one of the oil and the air to the gap is controlled according to the temperature detected by the temperature sensor.

  ADVANTAGE OF THE INVENTION According to this invention, the rotary machine which can perform effective cooling can be provided, reducing the loss in a rotor.

It is a sectional side view which shows the structure of the rotary machine in embodiment of this invention. It is a front sectional view showing the configuration of the rotating machine in the embodiment of the present invention. It is a sectional side view which shows another example of a structure of the rotary machine in embodiment of this invention. It is a figure which shows the structure of the circulation system in embodiment of this invention. It is a figure which shows the relationship between the position of the radial direction of a rotor, and the loss in a rotor. It is a figure which shows the difference in the cooling performance by a refrigerant temperature. It is a figure explaining the control using the temperature sensor in embodiment of this invention. It is a sectional side view which shows the structure of the rotary machine in the modification 1. It is a sectional side view which shows the structure of the rotary machine in the modification 2.

  A rotating machine 100 according to an embodiment of the present invention includes a case 10, a stator core 12, a stator coil 14, a rotor 16, a rotor shaft 18, a rotor shaft refrigerant, as shown in a side sectional view of FIG. 1 and a front sectional view of FIG. The flow path 20, the rotor refrigerant flow path 22, the air supply port 24, and the air flow path 26 are configured.

  The case 10 houses the components of the rotating machine 100 and mechanically holds them. The stator core 12 is a cylindrical magnetic body. The stator core 12 has a slot for accommodating the stator coil 14. The stator coil 14 is housed in a slot of the stator core 12 and generates a magnetic field with respect to the rotor 16 when an electric current flows. The rotor 16 is a columnar magnetic body and is disposed so that the inner peripheral surface of the stator core 12 and the outer peripheral surface face each other with the gap G interposed therebetween. A permanent magnet is inserted into and fixed to the rotor 16 in a magnet insertion hole extending in the axial direction. The rotor 16 receives the magnetic field from the stator coil 14 and is rotated in the stator core 12. The rotor 16 is connected to a rotor shaft 18 that is a rotation shaft, and the rotational force is transmitted to the outside of the rotating machine 100 by the rotor shaft 18.

  A rotor shaft refrigerant flow path 20 is formed in the rotor shaft 18. The rotor shaft refrigerant flow path 20 is a refrigerant flow path, and is provided so as to communicate with the inside of the rotor 16 along the axial direction of the rotor shaft 18. The in-rotor coolant channel 22 is formed in the rotor 16 as a coolant channel. The in-rotor refrigerant flow path 22 is formed so as to communicate with the rotor shaft refrigerant flow path 20 and is provided so that the refrigerant is supplied to the gap G between the stator core 12 and the rotor 16 toward the outer peripheral surface of the rotor 16.

  The number of the in-rotor refrigerant flow paths 22 may be not limited to one, but may be plural. For example, as illustrated in FIGS. 1 and 2, the rotor internal coolant flow path 22 is provided radially from the rotor shaft coolant flow path 20 toward the outer peripheral surface of the rotor 16. The in-rotor refrigerant flow path 22 may be communicated with an end portion of the rotor shaft refrigerant flow path 20 or may be communicated in the middle of the rotor shaft refrigerant flow path 20. For example, as shown in the side sectional view of FIG. 3, the in-rotor coolant channel 22 may be provided from a plurality of locations of the rotor shaft coolant channel 20 along the axial direction of the rotor 16. At this time, it is preferable to provide the in-rotor refrigerant flow path 22 in the vicinity of the axial center position of the rotor 16. By providing the in-rotor refrigerant flow path 22 in the vicinity of the center position in the axial direction of the rotor 16, the refrigerant supplied to the gap G can be made to flow evenly toward both ends of the rotor 16, and the cooling uniformity is ensured. be able to.

  The refrigerant is not particularly limited as long as it is liquid, and can be oil, water, or the like. However, it is preferable to use oil for electrical insulation retention. The oil may be, for example, mineral oil (naphthenic, paraffinic, etc.), partially synthetic oil, synthetic oil (PAO, etc.).

  The air supply port 24 is a path serving as a supply source for supplying air used for cooling to the rotating machine 100. The air flow path 26 is an air flow path formed in the stator core 12. The air flow path 26 communicates with the air supply port 24 and is provided from the air supply port 24 to the gap G between the stator core 12 and the rotor 16. Air supplied from the air supply port 24 is introduced into the gap G through the air supply port 24. In this embodiment, air is applied, but any gas that can be used for cooling may be used, and for example, nitrogen may be used.

  FIG. 4 is a diagram illustrating a configuration of a refrigerant circulation system 200 suitable for the rotating machine 100. The circulation system 200 is configured in the transaxle 30 and includes a differential gear 32, an oil pump 34, a heat exchanger 36, an oil pan 38, and an air pump 40.

  The refrigerant (oil) stored in the oil pan 38 is sucked up by the oil pump 34 provided in the differential gear 32, cooled by the heat exchanger 36, and then supplied to the rotating machine 100. The refrigerant supplied to the rotating machine 100 flows to the in-rotor refrigerant flow path 22 via the rotor shaft refrigerant flow path 20, and, as the rotor 16 rotates, the outer peripheral surface of the rotor 16, that is, the stator core 12 through the in-rotor refrigerant flow path 22. To the gap G between the rotor 16 and the rotor 16. On the other hand, air is introduced from the air pump 40 into the air supply port 24 and supplied to the gap G through the air flow path 26 of the stator core 12.

  The refrigerant (oil) and air supplied to the gap G are mixed to generate a two-phase flow of gas and liquid, and heat is exchanged between the rotating machine 100 and the refrigerant and is discharged through the gap G. The refrigerant (oil) discharged from the rotating machine 100 is returned to the oil pan 38 again.

  FIG. 5 is a diagram showing the relationship between the radial position of the rotor 16 and the loss in the rotor. As is apparent from FIG. 5, most of the rotor loss is loss in the core of the rotor 16, and the distribution is concentrated on the outer peripheral portion of the rotor 16. The main cause of the temperature rise of the magnet of the rotor 16 is heating from the outer peripheral surface of the rotor 16.

  In the rotating machine 100 according to the present embodiment, a gap G that directly touches the outer peripheral surface of the rotor 16 serving as a heating source for the magnets of the rotor 16 is used as a refrigerant flow path. Thereby, heat can be efficiently exchanged with the refrigerant at a position closest to the heating source. That is, cooling can be effectively performed without increasing the flow rate of the refrigerant as compared with the method of indirectly cooling from other parts.

  In particular, since the gap G has a large speed gradient between the stator core 12 side and the rotor 16 side, a heat transfer coefficient several tens of times higher than that in the case of simply flowing the same flow rate of refrigerant through the flow path can be obtained.

  FIG. 6 is a diagram illustrating a difference in cooling performance depending on the refrigerant temperature. As is clear from FIG. 6, the temperature of the magnet is lower when oil is used than when air is used as the refrigerant, and the oil has better heat capacity and heat transfer coefficient than air and has better cooling characteristics. On the other hand, a liquid such as oil has a higher viscosity than a gas such as air. Therefore, when oil is supplied as a refrigerant to the gap G between the stator core 12 and the rotor 16, drag loss due to rotation of the rotor 16 occurs.

  In rotating machine 100 in the present embodiment, when supplying refrigerant, oil and air are mixed and supplied to gap G as a two-phase flow, thereby reducing drag loss compared to when only oil is supplied. be able to. On the other hand, since oil having better cooling characteristics than air is mixed, the cooling capacity for the rotating machine 100 can be increased.

  Here, the void ratio = air volume / (air volume + oil volume) is preferably 0.05 or more and 0.9 or less. Particularly preferably, the void ratio is 0.1 or more and 0.5 or less. By setting the void ratio in such a range, the cooling effect can be enhanced while reducing the drag loss with respect to the rotor 16.

  Further, the flow path diameter (inner diameter) of the air flow path 26 is preferably smaller than the flow path diameter (inner diameter) of the in-rotor refrigerant flow path 22. As a result, when the oil and air are mixed to form a two-phase flow, air bubbles in the oil can be reduced, the uniformity of the entire refrigerant can be improved, drag loss can be reduced, and the cooling effect can be achieved uniformly. Can be high. In particular, the channel diameter (inner diameter) of the air channel 26 is preferably 1 mm or less.

  Further, as shown in FIG. 7, a temperature sensor 50 is provided in the rotor 16, the temperature of the rotor 16 is measured by the temperature sensor 50, and the output of the temperature sensor 50 is received by the control device 300 to receive the oil pump 34 or air pump 40 may be configured to be controlled. For example, the higher the temperature output from the temperature sensor 50, the higher the output of the oil pump 34 and the greater the amount of refrigerant (oil) supplied to the rotating machine 100. Further, for example, the higher the temperature output from the temperature sensor 50, the higher the outputs of the oil pump 34 and the air pump 40, and the total supply amount of refrigerant (oil) and air to the rotating machine 100 may be increased.

  The temperature sensor 50 only needs to be able to directly or indirectly measure the temperature of the rotating machine 100 and is not limited to the configuration provided in the rotor 16. For example, the temperature sensor 50 may be provided in the oil pan 38 and indirectly measure the temperature of the rotating machine 100 from the temperature of the refrigerant (oil).

<Modification 1>
As shown in the side sectional view of FIG. 8, the rotating machine 102 in Modification 1 includes a case 10, a stator core 12, a stator coil 14, a rotor 16, a rotor shaft 18, a rotor shaft refrigerant flow path 20, an air supply port 24, air The flow path 26 and the refrigerant | coolant storage part 52 are comprised. In this modification, the same components as those of the rotating machine 100 are denoted by the same reference numerals and description thereof is omitted.

  The refrigerant storage unit 52 is provided at the end of the rotor 16 so as to cover the end of the rotor 16 and the gap G between the stator core 12 and the rotor 16. The refrigerant is supplied from the rotor shaft refrigerant flow path 20 to the refrigerant storage unit 52, and the refrigerant is supplied to the gap G through the refrigerant storage unit 52. On the other hand, air is supplied from the air supply port 24 to the gap G through the air flow path 26 of the stator core 12. In this modification, a two-phase flow of the refrigerant and air is formed in this way, and cooling is performed through the gap G.

<Modification 2>
As shown in the side sectional view of FIG. 9, the rotating machine 104 in Modification 2 includes a case 10, a stator core 12, a stator coil 14, a rotor 16, a rotor shaft 18, an air supply port 24, an air flow path 26, and a refrigerant nozzle 54. It is comprised including. In this modification, the same components as those of the rotating machine 100 are denoted by the same reference numerals and description thereof is omitted.

  The refrigerant nozzle 54 is provided such that the nozzle hole is directed to the gap G between the stator core 12 and the rotor 16. The refrigerant is supplied from the refrigerant nozzle 54 to the gap G. On the other hand, air is supplied from the air supply port 24 to the gap G through the air flow path 26 of the stator core 12. In this modification, a two-phase flow of the refrigerant and air is formed in this way, and cooling is performed through the gap G.

  Also with the configurations of the first and second modifications, effective cooling can be performed while reducing the loss in the rotor as in the above embodiment.

  The rotor shaft refrigerant flow path 20 and the rotor internal refrigerant flow path 22 for supplying the refrigerant, the refrigerant storage section 52, the refrigerant nozzle 54, and the air supply port 24 and the air flow path 26 for supplying air are provided. It is good also as the structure replaced. That is, in the above-described embodiment and modifications 1 and 2, air may be supplied by the means for supplying the refrigerant, and the refrigerant may be supplied by the means for supplying air.

  Moreover, in the said embodiment and the modification 1 and 2, although it was set as the structure which supplies a refrigerant | coolant and air separately with respect to the gap | interval G, it is good also as a structure supplied after mixing.

  DESCRIPTION OF SYMBOLS 10 Case, 12 Stator core, 14 Stator coil, 16 Rotor, 18 Rotor shaft, 20 Rotor shaft refrigerant flow path, 22 Rotor refrigerant flow path, 24 Air supply port, 26 Air flow path, 30 Transaxle, 32 Differential gear, 34 Oil pump, 36 heat exchanger, 38 oil pan, 40 air pump, 50 temperature sensor, 52 refrigerant storage unit, 54 refrigerant nozzle, 100, 102, 104 rotating machine, 200 circulation system, 300 controller.

Claims (7)

A stator and a rotor that rotates relative to the stator;
An oil supply path for supplying oil to a gap between the stator and the rotor via a flow path passing through the center of the rotor shaft connected to the rotor;
An air supply path for supplying air from the stator side to the gap;
A rotating electric machine comprising:
The rotary electric machine characterized in that a flow path diameter of the air supply path is smaller than a flow path diameter of the oil supply path, and oil and air are simultaneously supplied to the gap to make the gap a refrigerant flow path. The rotating electrical machine according to claim 1,
In the gap, the rotary electric machine is characterized in that the oil and the air are in a gas / liquid two-phase flow. The rotating electrical machine according to claim 1 or 2,
The rotary electric machine, wherein the oil supply path has a plurality of flow paths connected to the gap. The rotating electrical machine according to any one of claims 1 to 3,
An oil storage part for storing the oil at the axial end of the rotor;
A rotating electrical machine that supplies the oil from the oil storage section to the gap. The rotating electrical machine according to any one of claims 1 to 4,
The rotating electrical machine, wherein the air supply path has a plurality of flow paths connected to the gap. It is a rotary electric machine of any one of Claims 1-5,
A rotating electrical machine having a void ratio (air volume / (oil volume + air volume)) between the oil and the air of 0.05 or more and 0.9 or less. The rotating electrical machine according to any one of claims 1 to 6,
A temperature sensor for measuring the temperature of the rotor;
A rotating electrical machine that controls a supply amount of at least one of the oil and the air to the gap according to a temperature detected by the temperature sensor.

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