JP2014064433A - Rotor shaft of rotary electric machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a coolant sent out from a through hole from being interrupted in a rotor shaft of a rotary electric machine in which an inner portion of a hollow shaft is used as a passage of the coolant and the coolant is sent out from the through hole formed in a radial direction.SOLUTION: A spiral shaped guide groove 44 is provided on an inner wall surface 42 of a rotor shaft 18 that is a hollow shaft. A coolant receives a force from the guide groove 44 through rotations of the rotor shaft 18 and is sent to a position of a through hole 40. The coolant is supplied to a periphery of the through hole 40 thereby preventing interruption of the coolant sent out from the through hole 40.

Description

  The present invention relates to a rotor shaft of a rotating electrical machine, and more particularly to a structure of a rotor shaft through which a coolant flows.

  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. The rotating electrical machine has two members that are arranged coaxially and relatively rotate. Normally, one is fixed and the other rotates. A coil is arranged on a fixed member (stator), and a rotating magnetic field is formed by supplying AC power to the coil. The other member (rotor) is rotated by the interaction with the magnetic field.

  The rotor has a rotor core that interacts with a rotating magnetic field formed by the stator, and a rotor shaft that rotatably supports the rotor core. The rotor shaft rotates integrally with the rotor core and functions as an output shaft that transmits the rotor rotation to the outside.

  The rotating electrical machine has a heat source such as a coil arranged in the stator and a permanent magnet arranged in the rotor, and these need to be cooled. In the following Patent Document 1, a technique is described in which a rotor shaft is a hollow shaft and this is used as a flow path for sending a coolant. A through-hole in the radial direction is formed at a predetermined position of the rotor shaft, and the coolant is sent out from the through-hole, and the coolant is sent to a portion to be cooled (see, for example, paragraphs 0022 and 0023).

  Patent Document 2 below describes a technique in which a groove extending in the axial direction is provided on the inner wall surface of a hollow rotor shaft, and a coolant is sent with a gradient in the bottom surface of the groove (paragraphs 0066-0070, (See FIG. 6).

JP 2011-254578 A JP 2010-142090 A

  When the coolant is sent out through the radial through-hole as in Patent Document 1, the coolant is sent to the through-hole in the vicinity of the radial through-hole. In a position away from the coolant, the coolant may not flow well toward the through hole. If the flow toward the through hole is not formed, the coolant may not be sufficiently sent from the through hole. A large amount of the coolant that has not flowed to the through-holes flows to other portions, and wasteful supply excessively occurs in those portions.

  An object of the present invention is to guide the coolant supplied to the inside of a hollow rotor shaft into a radial through hole formed in the rotor shaft.

  The rotor shaft of the rotating electrical machine of the present invention is a hollow shaft, and has a through passage that connects the inside and the outside of the rotor shaft. The rotor shaft is further formed with a guide groove extending spirally on the inner wall surface thereof. The coolant supplied to the inner space of the hollow rotor shaft receives a force from the spiral guide groove by the rotation of the rotor shaft, and a flow toward the through flow path is formed.

  By forcibly sending the coolant toward the through channel by the guide groove, the flow rate of the coolant sent from the through channel can be secured.

It is a figure which shows schematic structure of the rotary electric machine of this embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view showing a schematic configuration of a rotating electrical machine 10 of the present embodiment. The rotating electrical machine 10 includes a substantially cylindrical or disk-shaped rotor 12 and a substantially cylindrical or annular stator 14 disposed so as to surround the rotor 12. In the following, the shapes of the rotor 12 and the stator 14 are referred to as a column and a cylinder for simplicity. The column of the rotor 12 and the cylinder of the stator 14 are arranged concentrically.

  The rotor 12 includes a cylindrical rotor core 16 formed by laminating disc-shaped electromagnetic steel plates, and a rotor shaft 18 that passes through the center of the rotor core 16. In order to fix the rotor core 16 and the rotor shaft 18, the rotor core 16 is integrally fixed to the rotor shaft 18 so as to be sandwiched between the caulking member 20 and the end plate 22 in the direction along the rotor shaft 18. The rotor 12 rotates around the rotor shaft 18.

  A permanent magnet 24 is disposed on the outer peripheral surface of the rotor core 16 or a portion close to the outer peripheral surface. The permanent magnets 24 are arranged in the circumferential direction at a predetermined interval. In this rotating electrical machine 10, holes are formed at predetermined positions of each of the electromagnetic steel sheets to be laminated, and when the electromagnetic steel sheets are laminated, the formed hole has an accommodating portion for accommodating the permanent magnet 24. I am trying to configure it. The permanent magnet 24 is inserted into the housing portion, and the permanent magnet 24 is fixedly disposed on the rotor core 16.

  A flow path 26 through which the coolant flows is formed at a position on the radially inner side of the permanent magnet 24 of the rotor core 16. The flow path 26 may be provided so that the coolant directly contacts the surface of the permanent magnet 24, or may be provided adjacent to the permanent magnet 24 via a member constituting the rotor core 16. In any case, the flow path 26 is disposed adjacent to the permanent magnet 24. Hereinafter, the flow path 26 is referred to as an adjacent flow path 26 in the sense that it is disposed adjacent to the permanent magnet 24. The adjacent flow path 26 is formed by opening holes at a predetermined position of each of the electromagnetic steel sheets and connecting the holes when the electromagnetic steel sheets are laminated, as in the case of the permanent magnet housing described above. The adjacent flow paths 26 are open on both end faces in the rotation axis direction of the rotor core 16. However, you may make it open only to one side. Supply of the cooling liquid to the adjacent flow path 26 is performed from the rotor shaft 18 through an end plate internal flow path 28 provided in the end plate 22 and a core internal flow path 30 provided in the rotor core 16. . The end plate flow path 28 is formed in the end plate 22 so as to extend in the radial direction. One end of the in-core flow path 30 opens to the end plate flow path 28, and the other end opens to the center of the adjacent flow path 26, that is, the central position in the axial direction.

  The rotor shaft 18 is a hollow shaft, and one end is closed by a plug 32. The rotor shaft 18 is rotatably supported by a case (not shown) by two bearings 34 disposed on the opposite sides of the rotor core 16. In a space inside the hollow rotor shaft 18, a supply pipe 36 for supplying a cooling liquid is inserted into this space. One or a plurality of supply holes 38 are provided on the side surface of the distal end portion of the supply pipe 36. Cooling liquid is sent to the supply pipe 36 from a pump (not shown), and the cooling liquid is discharged from the supply hole 38 and supplied to the space inside the rotor shaft 18.

  The rotor shaft 18 is provided with one or a plurality of through holes 40 extending in the radial direction connecting the inner side and the outer side. The coolant is supplied from the inside to the outside of the rotor shaft 18 through the through hole 40. That is, the through hole 40 is a flow path for the coolant. A spiral groove 44 is formed on the inner wall surface 42 of the rotor shaft 18. The groove 44 has a function of guiding the coolant in the rotor shaft 18 toward the through hole 40 as described later. Hereinafter, the groove 44 is referred to as a guide groove 44. The direction of the spiral of the guide groove 44 is opposite to the position of the through hole 40.

  The stator 14 has a stator core 46 having teeth arranged along the circumferential direction on the inner peripheral surface of a cylinder, and a stator coil 48 wound around the teeth. Stator core 46 is formed by laminating electromagnetic steel sheets having the same shape as the cross-sectional shape of the stator core when completed. A coil 48 is formed by winding a conductive wire around the teeth of the stator core 46. As a result, the teeth become magnetic poles. A portion of the coil 48 that protrudes from the end face of the stator core 46 is called a coil end.

  The coolant is supplied to the space inside the rotor shaft 18 by the supply pipe 36. The position to be supplied is determined by the position of the supply hole 38, and is supplied to a portion corresponding to the rotor core 16 in the rotating electrical machine 10. When discharged from the supply hole 38, the coolant is directed radially outward. At this time, the flow of the coolant does not have a circumferential component. When the coolant reaches the inner wall surface 42, it starts to circulate by being dragged to the inner wall surface 42 by the rotation of the rotor shaft 18. Since the coolant does not immediately reach the same speed as the inner wall surface 42, a relative speed is generated between the coolant and the inner wall surface 42. Due to this relative speed, the coolant receives a force from the guide groove 44 and moves along the axial direction of the rotor shaft 18. The direction of the spiral of the guide groove 44 is determined so that the direction of this movement is the direction toward the through hole 40.

  The coolant around the through hole 40 inside the rotor shaft 18 receives a centrifugal force due to the rotation of the rotor shaft 18, and is sent to the outside of the rotor shaft 18 through the through hole 40. The opening on the outer surface of the rotor shaft of the through hole 40 is provided at a position where the end plate 22 is disposed in the rotational axis direction, and is provided so as to coincide with the position of one end of the end plate flow path 28 in the circumferential direction. . Thereby, the coolant is sent out from the through hole 40 to the end plate flow path 28. The cooling fluid flows radially outward in the end plate flow path 28 by centrifugal force, and flows into the core flow path 30 from the vicinity of the outer end. Furthermore, it flows through the in-core flow path 30 and reaches the adjacent flow path 26. The coolant is divided into two directions (the left-right direction in FIG. 1) in the adjacent flow path 26, and flows toward the opening on the end face of the rotor core 16 and flows out from this opening.

  The coolant is sent toward the vicinity of the through hole 40 by the guide groove 44 provided on the inner wall surface 42 of the rotor shaft 18 so that the coolant near the through hole 40 is not reduced. As a result, air can be prevented from biting into the coolant sent through the through hole 40, and the coolant can be sent stably into the rotor core 16. In addition, it is possible to prevent the coolant from staying excessively at a position far from the through hole 40 of the rotor shaft 18. When the cooling liquid stays excessively, the cooling liquid may leak out of the rotor shaft from an unexpected location, but this can also be suppressed.

  In the rotating electrical machine 10, the coolant sent from the through hole 40 goes to the adjacent flow path 26 to cool the rotor core 16, particularly the permanent magnet 24. However, the coolant may be discharged directly from the through hole 40 toward the stator coil 48, particularly the coil end. For this purpose, it is also preferable that the through hole 40 is positioned away from the rotor core 16 from the illustrated position and is shifted from the end plate 22.

  The flow of the cooling liquid in the adjacent flow path 26 can be a one-way flow from one end to the other end. For example, one end (the left end in FIG. 1) of the adjacent flow path 26 can be opposed to the outer end of the end plate flow path 28 to directly receive the coolant from the end plate flow path 28. The received coolant flows in the adjacent flow path 26 toward the other end (rightward in FIG. 1), and flows out from the other end.

  The guide groove 44 may be one or two or more. Further, the pitch may be changed depending on the position, and the groove width may be changed. The guide groove 44 can be formed by engraving on the inner wall surface 42 of the rotor shaft, that is, by cutting it. Further, a linear member or a belt-like member wound spirally may be inserted into the rotor shaft 18 so that a portion between the members becomes a groove. Furthermore, a cylindrical sleeve having a groove formed on the inner peripheral surface may be inserted into the rotor shaft 18.

  The cooling liquid can also be used as a lubricating oil for lubricating a bearing or the like. In addition, when the rotating electrical machine is disposed in a device that combines hydraulic oil and lubricating oil for driving a hydraulic actuator as in a conventional automatic transmission, this combined fluid can be used as a coolant.

  The rotary electric machine 10 is not limited to the above-described embedded magnet type rotary electric machine, and the present invention can be applied to other types of rotary electric machines such as a surface magnet type rotary electric machine and a machine that does not use a permanent magnet.

  DESCRIPTION OF SYMBOLS 10 Rotating electrical machine, 12 Rotor, 14 Stator, 16 Rotor core, 18 Rotor shaft, 22 End plate, 24 Permanent magnet, 36 Supply pipe, 38 Supply hole, 40 Through hole (through channel), 42 Inner wall surface, 44 Guide groove

Claims (1)

A rotor shaft that supports a rotor core of a rotating electrical machine,
The rotor shaft is a hollow shaft, and has a through channel for connecting the inner side and the outer side of the rotor shaft and sending out the cooling liquid supplied to the inner side of the rotor shaft,
On the inner wall surface of the rotor shaft, a guide groove extending in a spiral shape is formed to form a flow of cooling liquid toward the through flow path.
Rotor shaft.

Images