JP2013038994A - Rotary electric machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce pressure loss of a coolant discharged from a rotor shaft to a coil in a rotary electric machine which further has an input shaft penetrating a hollow part of a hollow rotor shaft and sends the coolant through a passage in the input shaft.SOLUTION: First and second radial passages 60, 62, which send a coolant to a coil, are provided in a rotor shaft 24. Communication passages 56, 58 are provided at positions, which are the same positions as the radial passages 60, 62, in an input shaft 26 penetrating through a hollow part of the rotor shaft 24 in the rotation axis direction of the rotor. The coolant flowing in an inner passage 50 in the input shaft 26 passes the communication passages 56, 58 to reach an outer passage 52 and then passes the radial passages 60, 62 to be discharged to the coil. The pathway flowing in the outer passage 52 is short and the pressure loss is reduced.

Description

  The present invention relates to a rotating electrical machine, and more particularly to a structure related to cooling thereof.

  An electric motor that converts electrical energy into rotational kinetic energy, a generator that converts rotational kinetic energy into electrical energy, and an electric device that functions as both the motor and the generator are known. Hereinafter, these electric devices are referred to as rotating electric machines.

  A rotating electrical machine that cools with a liquid is known (see Patent Document 1 below). In the rotating electrical machine described in Patent Document 1 below, the coolant is sent through the hollow portion of the hollow rotor shaft, and the coolant is discharged toward the stator coil through a guide hole formed in the rotor shaft in the radial direction. The coil is cooling.

JP 2010-45894 A

  In a rotating electrical machine that further includes an inner shaft that passes through a hollow portion of a hollow rotor shaft and that sends coolant through a flow path in the inner shaft, in order to discharge the coolant from the rotor shaft toward the coil, the rotor It is necessary to send the coolant through the radial gap between the shaft and the inner shaft. There is a problem that the pressure loss when flowing through the gap between the rotor shaft and the inner shaft is large.

  The present invention aims to reduce the pressure loss.

  The rotating electrical machine of the present invention has a hollow rotor shaft and an inner shaft that penetrates the hollow portion of the rotor shaft. Inside the inner shaft, an inner flow path is provided that extends along the rotation axis direction of the rotor and through which the cooling liquid flows. The cooling liquid also flows in a radial gap between the rotor shaft and the inner shaft. This gap is referred to as an outer channel. In order to send the coolant from the inner channel to the outer channel, a communication channel that connects these channels is formed on the inner shaft. Further, a radial flow path is formed in the rotor shaft to communicate the inner peripheral surface and the outer peripheral surface of the rotor shaft in order to send the coolant from the outer flow channel toward the stator coil. The radial flow path is formed near the core end of the rotor. This position corresponds to the inside of the coil end portion of the coil disposed on the stator, and the coolant sent from the coil heads toward the coil end portion. The communication flow path is provided at the same position as the radial flow path in the rotation axis direction of the rotor. This shortens the length of the fluid flowing from the inner channel to the radial channel and flowing through the outer channel.

  By reducing the length of the fluid flowing from the inner channel to the radial channel and flowing through the outer channel, the pressure loss is reduced.

It is a schematic block diagram of the motive power apparatus containing a rotary electric machine. It is sectional drawing containing the rotating shaft line of the rotary electric machine of this embodiment. It is a figure which shows the state seen from the axial direction of the rotor.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a diagram schematically illustrating an example of a power plant 10 having doubly arranged shafts. The power unit 10 includes another prime mover 14 in addition to the rotating electrical machine 12. The other prime mover 14 may be a heat engine such as an internal combustion engine, or may be a rotating electric machine. Furthermore, it may be a combination of a plurality of prime movers.

  The rotating electrical machine 12 includes a rotor 16 and a stator 18. The stator 18 includes a wound coil 20, and by supplying electric power to the coil 20 from the outside, a rotating magnetic field is formed inside the stator 18. The rotor 16 has a hollow rotor shaft 24 supported by the bearing 22 and is rotatable about the rotor shaft 24 as a central axis. The rotor 16 is magnetically coupled to the rotating magnetic field formed by the stator 18 and rotates. Hereinafter, the central axis of the rotor shaft 24 is referred to as the rotation axis of the rotor.

  The input shaft 26 to which the power of the other prime mover 14 is input passes through the hollow portion of the rotor shaft 24 and is located inside the rotor shaft 24. The input shaft 26 and the rotor shaft 24 constitute a double shaft, and one end of each shaft is coupled to a common output integration device 30. The output integration device 30 integrates the power of the rotating electrical machine 12 and the other prime mover 14 and outputs the power from the output shaft 28. The output integration device 30 may include, for example, a speed reducer that decelerates the output from the rotating electrical machine 12, and integrates the reduced output of the rotating electrical machine 12 and the outputs of the other prime movers 14. The output integration device 30 may include a clutch, and selectively couples the output of the rotating electrical machine 12 or other prime mover 14 with the output shaft 28 and sends the outputs of both prime movers to the output shaft 28. Only the output of the prime mover can be selected to be sent to the output shaft. Further, the output integration device 30 may include a transmission, and for example, the output of the rotating electrical machine 12 can be connected to the output shaft 28 with a binary gear ratio.

  Lubricating oil is supplied from the oil pump 32 to the bearings and the like that support the rotating parts of the rotating electrical machine 12 and the output integrating device 30. Lubricating oil sent out from the oil pump 32 is sent through a flow path formed in the input shaft 26 and supplied to each part of the power unit 10. Lubricating oil may also be used as a working fluid that operates a hydraulic clutch or the like in the power unit. The lubricating oil also has an action as a coolant that cools each part of the power unit 10. In the following description, since the effect to which attention is paid is the cooling action among the actions of the lubricating oil, the lubricating oil will be described as a cooling liquid.

  FIG. 2 is a view showing a cross section including the rotation axis of the rotating electrical machine 12. The rotating electrical machine 12 is housed in a case 34, and the stator 18 is fixed to the case 34. Stator 18 includes a stator core 36 formed by laminating electromagnetic steel plates in the direction of the rotation axis of the rotor. The stator core 36 has a cylinder and a plurality of teeth that protrude from the inner peripheral surface of the cylinder and are arranged in the circumferential direction. A conductive wire is wound around the teeth to form the coil 20. A portion of the coil that protrudes from the stator core 36 in the direction of the rotation axis of the rotor is a coil end portion.

  The rotor 16 has a substantially cylindrical rotor core 38 in which electromagnetic steel plates are laminated in the rotation axis direction of the rotor, and end plates 40 and 41 are arranged at both ends of the rotor core 38 in the rotation axis direction so as to sandwich the rotor core 38. Is done. The end plates 40 and 41 have a substantially disc shape, and constitute one cylindrical body together with the rotor core 38. A hollow rotor shaft 24 passes through the center of the rotor core 38 and the end plates 40 and 41. The rotor shaft 24 is provided with a flange 42, and the end plate 40 is in contact therewith. A caulking ring 44 is provided at the other end of the rotor core 38. The rotor core 38 and the two end plates 40 and 41 are fixed to the rotor shaft 24 by caulking the caulking ring 44 to the rotor shaft 24. The rotor core 38 and the rotor shaft 24 rotate together.

  A permanent magnet (not shown) is embedded in the rotor core 38. The permanent magnet is magnetically coupled with the rotating magnetic field formed by the stator 18, and the rotor 16 rotates. The rotor shaft 24 is rotatably supported by the case 34 via a bearing 22, for example, a rolling bearing such as a ball bearing. The rotor shaft 24 is splined to the extension shaft 46 at the right end in the figure, and the rotation of the rotor 16 is sent to the output integrating device 30 by the extension shaft 46.

  An input shaft 26 is disposed in the hollow portion of the rotor shaft 24 so as to penetrate the hollow portion. The input shaft 26 is supported by the rotor shaft 24 via a bearing 48, for example, a needle bearing. The rotor shaft 24 and the input shaft 26 can be arranged so as to have a common rotation axis, that is, coaxially.

  A through hole is formed in the input shaft 26 along the direction of the rotation axis thereof, and this becomes a flow path 50 of a coolant (lubricating oil) and is supplied to a necessary portion in the power unit 10. An annular gap is formed between the doubly arranged rotor shaft 24 and the input shaft 26, and this space also serves as a coolant flow path 52. The flow path 50 and the flow path 52 are partitioned by the input shaft 26, and the flow path 50 is disposed inside the input shaft 26 and the flow path 52 is disposed outside. Hereinafter, the flow channel 50 will be described as the inner flow channel 50 and the flow channel 52 will be described as the outer flow channel 52. In order to allow the coolant to flow from the inner channel 50 to the outer channel 52, both ends of the input shaft 26 are opened on the inner peripheral surface and the outer peripheral surface of the input shaft, and communication channels 54, 56, 58 communicating these. Is formed. In this rotating electrical machine 12, the communication flow paths 54, 56, and 58 are provided at three locations in the rotation axis direction. The first communication channel 54 is provided in the central portion of the rotor core 38 in the direction of the rotation axis of the rotor. The second and third communication channels 56 and 58 are provided in the vicinity of the end of the rotor core 38 in the rotation axis direction. The positions of the second and third communication channels 56 and 58 will be described again later.

  The first communication channel 54 communicates the inner channel 50 and the outer channel 52, and the coolant flows from the inner channel 50 to the outer channel 52 through the first communication channel 54. The coolant sent to the outer flow path 52 cools the rotor core 38 from the inside, and also reduces the temperature of the permanent magnet built in the rotor core 38. One first communication channel 54 may be provided, or two or more first communication channels 54 may be provided in the circumferential direction.

  In the vicinity of the end of the rotor core 38 of the rotor shaft 24, both ends are opened on the inner peripheral surface and the outer peripheral surface of the rotor shaft 24, and radial flow paths 60, 62 communicating these are provided. The coolant in the outer flow path 52 is sent to the outside of the rotor shaft 24 via the radial flow paths 60 and 62 by centrifugal force accompanying the rotation of the rotor 16, and is applied to the coil end portion of the coil 20. Cooling. Since the radial flow paths 60 and 62 are disposed in a portion surrounded by the coil end portion, the delivered coolant is applied to the coil end portion. However, as shown in the drawing, parts such as bearings are arranged in a range surrounded by the coil end portion, and a space for arranging the radial flow paths 60 and 62 is limited. In the rotating electrical machine 12, radial flow paths 60 and 62 are provided at or adjacent to the positions where the end plates 40 and 41 are disposed in the rotor axial direction. In particular, the left radial flow path (hereinafter referred to as the first radial flow path) 60 in the drawing is provided at the position of the flange 42. As shown in FIG. 3, the flange 42 is formed with a notch 64 at the same position as the circumferential position of the radial flow path 60, and the coolant sent from the first radial flow path 60 is cut off. It goes to the coil end portion through the notch 64. Further, instead of providing the notch 64 in the flange, the first radial flow path 60 may be provided extending inside the flange 42. One first radial flow path 60 may be provided, or two or more first radial flow paths 60 may be provided in the circumferential direction. The example shown in FIG. 3 is an example in which two are provided at equal intervals in the circumferential direction.

  The opening on the outer side of the second radial flow path 62 on the right side in the drawing is positioned to face the inner diameter of the end plate 41. The end plate 41 is provided with a radial groove 66 extending in the radial direction. The second radial flow path 62 and the radial groove 66 are disposed at the same position in the circumferential direction. As a result, the outer opening of the second radial flow path 62 and the inner end of the circumferential groove 66 face each other, and the coolant sent out from the second radial flow path 62 is received by the circumferential groove 66, and the circumferential direction It goes to the coil end portion through the groove 66. The outer end of the circumferential groove 66 can form a slope in which the depth of the groove gradually decreases toward the radially outer side, and the direction of the coolant to be sent out can be changed smoothly. A similar radial groove can also be provided on the left end plate 40 in the drawing, and the inner peripheral end of the radial groove and the opening on the outside of the first radial flow channel 60 are arranged to face each other. In this case, it is possible not to provide the notch 66 of the flange 42 or to form a radial flow path in the flange.

  When the flow path cross-sectional area of the outer flow path 52 is smaller than that of the inner flow path 50, the coolant is sent to the first and second radial flow paths 60 and 62 via the first communication flow path 54. Then, a large pressure loss occurs in the outer flow path 52. The second and third communication channels 56, 58 are arranged so that the coolant channel to the first and radial channels 60, 62 is shortened, and in particular, the channel in the outer channel 52 is shortened. The position can be determined.

  The position of the second communication channel 56 can be the same position as the first radial channel 60 in the direction of the rotation axis of the rotor. It is desirable that the opening on the outside of the second communication channel 56 and at least a part of the opening on the inside of the first radial channel 60 overlap. The rotor shaft 24 and the input shaft 26 rotate at a relative speed, and when the second communication flow channel 56 and the first radial flow channel 60 are in the same position in the circumferential direction, at least a part of both openings face each other. It becomes. The coolant is sent from the inner flow path 50 to the outer flow path 52 through the second communication flow path 56 and from the outer flow path 52 to the first radial flow path 60 toward the coil, particularly the coil end portion. Discharged.

  The position of the third communication channel 58 can be the same position as the second radial channel 62 in the rotation axis direction of the rotor. It is desirable that the opening on the outside of the third communication channel 58 and at least a part of the opening on the inside of the second radial channel 62 overlap. When the third communication flow path 58 and the second radial flow path 62 are in the same position in the circumferential direction, at least a part of the opening of both faces the arrangement. The coolant is sent from the inner channel 50 to the outer channel 52 through the third communication channel 56 and from the outer channel 52 to the first radial channel 60 toward the coil, particularly the coil end portion. Discharged.

  It is also possible to provide only one of the first and second radial flow paths 60 and 62. In this case, the second and third communication passages 56 and 58 can be provided only in the direction corresponding to the provided first or second radial flow path 60 or 62.

  The second and third communication channels 56 and 58 and the first and second radial channels 60 and 62 are arranged at the same position in the rotation axis direction of the rotor, respectively, so that the coolant flows through the outer channel 52. The flow distance is shortened, and the pressure loss is reduced accordingly.

  12 Rotating machine, 16 Rotor, 18 Stator, 20 Coil, 24 Rotor shaft, 26 Input shaft (inner shaft), 38 Rotor core, 40, 41 End plate, 42 Flange, 44 Caulking ring, 50 Inner channel, 52 Outer channel 54 1st communication flow path, 56 2nd communication flow path, 58 3rd communication flow path, 60 1st radial flow path, 62 2nd radial flow path.

Claims (1)

A rotor core, and a rotor having a hollow rotor shaft that rotates integrally with the rotor core;
A stator having a coil and disposed outside the rotor;
An inner shaft passing through the hollow portion of the rotor shaft;
A rotating electric machine including
The inner shaft has an inner channel that extends along the rotation axis direction of the rotor inside the inner shaft and through which the coolant flows.
The gap in the radial direction between the rotor shaft and the inner shaft becomes the outer flow path through which the coolant flows.
The rotor shaft has a radial flow path that communicates the inner peripheral surface and the outer peripheral surface of the rotor shaft in the vicinity of the end of the rotor core,
The inner shaft further has a communication channel that communicates the inner channel and the outer channel at the same position as the radial channel in the rotation axis direction of the rotor,
The coolant flowing through the inner flow path, the communication flow path, the outer flow path, and the radial flow path is discharged toward the stator coil.
Rotating electric machine.

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