JP2018164370A - Outer rotor structure of rotating electric machine - Google Patents

Abstract

In an outer rotor structure of a rotating electric machine, a shift of a central axis of a rotor due to a centrifugal force during operation is suppressed. An outer rotor structure includes a rotor body and a rotor core. The rotor body 22 includes a shaft mounting portion 24 for mounting a rotor shaft extending in the axial direction, a disk portion 26 projecting radially from the shaft mounting portion 24 toward the outer peripheral side, and an axial direction on the outer periphery of the disk portion 26. Includes a ring portion 28 projecting in an annular shape. The ring portion 28 has a concave portion 36 for arranging the rotor core on the inner peripheral side. The rotor core 40 is disposed in the concave portion 36 for arranging the rotor core of the ring portion 28 and has an annular shape provided with a predetermined number of magnetic poles in the circumferential direction. The outer rotor structure 20 further includes a spline 50 provided on the outer peripheral surface of the ring portion 28 for engagement with the gear reduction mechanism 16. [Selection] Figure 2

Description

  The present disclosure relates to an outer rotor structure of a rotating electric machine, and more particularly to an outer rotor structure of a rotating electric machine mounted on a transaxle.

  As a rotor constituting the rotating electrical machine, an inner rotor type disposed on the inner peripheral side of the stator and an outer rotor type disposed on the outer peripheral side of the stator are known. In an outer rotor type rotating electrical machine, an outer rotor is configured by arranging an annular rotor core that forms a rotor magnetic pole on the inner peripheral side of an annular edge of a rotor body having a substantially cup-like shape. Arranged at a predetermined interval on the inner peripheral side of the rotor core.

  For example, in Patent Document 1, in an outer rotor type AC generator driven by an engine, center positioning between a stator and an outer rotor when a V-belt for driving an auxiliary machine of a vehicle is suspended on the outer rotor. Discloses the use of radial bearings.

JP 2011-234557 A

  A rotating electrical machine for mounting on a vehicle is required to have a high output, and accordingly, the rotating electrical machine becomes large. When an outer rotor type rotating electrical machine is mounted on a vehicle, the outer diameter of the substantially cup-shaped rotor body is increased, and the displacement of the central axis of the rotor due to centrifugal force during operation is increased. The generated stress also increases. Therefore, an outer rotor structure of a rotating electrical machine that can suppress the deviation of the central axis of the rotor due to centrifugal force during operation and the stress generated therewith is desired.

  An outer rotor structure of a rotating electrical machine according to the present disclosure is an outer rotor structure of a rotating electrical machine in a transaxle having two rotating electrical machines arranged on multiple axes and a gear reduction mechanism, and is for attaching a rotor shaft extending in an axial direction. Shaft mounting portion, a disk portion projecting radially from the shaft mounting portion toward the outer peripheral side, and a ring having an annular annular protrusion in the axial direction on the outer periphery of the disc portion and a recess for arranging the rotor core on the inner peripheral side Ring portion for engagement with a gear reduction mechanism and a rotor core having an annular shape that is disposed in a rotor body including a portion, a recess portion for arranging a rotor core in the ring portion, and provided with a predetermined number of magnetic poles in the circumferential direction And a spline provided on the outer peripheral surface.

  According to the above configuration, the radial displacement is regulated by the gear reduction mechanism in which the outer peripheral surface of the annular ring portion on the outer periphery of the rotor body is engaged through the spline, and the displacement of the central axis of the rotor and accompanying this The generated stress is suppressed.

  According to the outer rotor structure of the rotating electrical machine having the above-described configuration, it is possible to suppress the deviation of the central axis of the rotor and the stress generated thereby due to centrifugal force during operation.

It is a figure which shows the transaxle by which the outer rotor type rotary electric machine which concerns on embodiment is mounted. It is sectional drawing which shows the outer rotor structure of the rotary electric machine which concerns on embodiment. As a comparative example, it is a figure which shows the transaxle by which the outer-rotor type rotary electric machine with which a reduction gear mechanism is engaged with a rotor shaft is mounted. It is sectional drawing which shows the outer rotor structure of the rotary electric machine in FIG.

  Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. The shape, material, and the like described below are examples for explanation, and can be appropriately changed according to the specifications of the outer rotor structure of the rotating electrical machine. Below, the same code | symbol is attached | subjected to the same element in all the drawings, and the overlapping description is abbreviate | omitted.

  FIG. 1 is a diagram showing a transaxle 10 on which an outer rotor type rotating electrical machine is mounted. The transaxle 10 is a device that works as a power source of a vehicle in cooperation with an engine (shown in parentheses in FIG. 1), and includes two rotating electric machines 12 and 14 arranged on multiple axes, a gear reduction mechanism 16, and power distribution. And a mechanism 18.

  The two rotating electrical machines 12 and 14 are three-phase synchronous rotating electrical machines that are mounted on the vehicle, and function as a motor function when power is supplied from a drive circuit (not shown), and are driven by the engine or braking the vehicle. Sometimes it is a motor generator that works as a power generation function.

  Of the two rotary electric machines 12 and 14, the first rotary electric machine 12 is driven by the engine via the power distribution mechanism 18 and mainly functions as a power generation function. The second rotating electrical machine 14 is an outer rotor type rotating electrical machine, and is connected to a power distribution mechanism 18 via a gear reduction mechanism 16. The second rotating electrical machine 14 mainly drives a motor drive shaft (not shown) via the gear reduction mechanism 16. Work as a function.

  The gear reduction mechanism 16 is a multistage reduction gear configured by a plurality of gear trains. Of the plurality of gear trains, the gear 19 is a gear that transmits power to the second rotating electrical machine 14. The power distribution mechanism 18 is a planetary gear mechanism that distributes power among the first rotating electrical machine 12, the second rotating electrical machine 14, and the engine in accordance with the traveling conditions of the vehicle.

  FIG. 2 is a cross-sectional view showing the outer rotor structure 20 of the second rotating electrical machine 14 in FIG. Hereinafter, unless otherwise specified, the outer rotor structure 20 of the second rotating electrical machine 14 is referred to as the outer rotor structure 20.

  The outer rotor structure 20 is a rotor structure of the second rotating electrical machine 14. In the second rotating electrical machine 14, an outer rotor structure 20 is disposed on the outer peripheral side of the stator 8 indicated by a two-dot chain line. The stator 8 is a stator of the second rotating electrical machine 14 and is fixed to a motor case (not shown). The stator 8 has a predetermined stator coil disposed on the stator core, and generates a rotating magnetic field by driving power from a driving circuit (not shown).

  The outer rotor structure 20 includes a rotor body 22 and a rotor core 40. The rotor body 22 includes a shaft attachment portion 24, a disc portion 26, and a ring portion 28. The rotor main body 22 formed by these has a substantially cup-like shape with a cylindrical shaft mounting portion 24 projecting from the center. The portion of the outer peripheral side edge in the substantially cup shape corresponds to the ring portion 28, and the bottom portion of the substantially cup shape corresponds to the disc portion 26. A space surrounded by the ring portion 28 and the disc portion 26 is an opening space portion 30 where the stator 8 is disposed.

  FIG. 2 shows the axial direction and the radial direction of the outer rotor structure 20. The axial direction is a direction in which the central axis CL of the outer rotor structure 20 extends, the opening space 30 side is one side, and the opposite direction to the one side is the other side. The radial direction is a radial direction from the central axis CL in a plane perpendicular to the axial direction. The direction toward the central axis CL is the inner peripheral side in the radial direction, and the direction away from the central axis CL is the outer peripheral side. The central axis CL is also the central axis of the rotor in the rotating electrical machine 14.

  The shaft attachment portion 24 is a cylindrical portion that is disposed in the central portion of the rotor body 22 and extends along the axial direction and has a shaft attachment hole 32. A rotor shaft 34 indicated by a two-dot chain line is attached to the shaft attachment hole 32. The rotor shaft 34 is a rotating shaft of the second rotating electrical machine 14, and both ends thereof are rotatably supported by a motor case (not shown). As a method of attaching the rotor shaft 34 to the shaft attachment hole 32, a coupling by press-fitting method, a coupling using a key and a key groove, a coupling by a shrink fitting method, or the like is used.

  The disc portion 26 is a disc-shaped portion that projects radially from the shaft attachment portion 24 toward the outer peripheral side in the rotor body 22.

  The ring portion 28 is an annular portion that protrudes from the outer peripheral end of the disc portion 26 toward one side in the axial direction in the rotor body 22. The ring portion 28 has a concave portion 36 for arranging the rotor core on the inner peripheral side. In the outer rotor structure 20, since the rotor core 40 is fitted in the recess 36, the recess 36 and the rotor core 40 overlap in a cross-sectional view. In FIG. 2, the recess 36 is illustrated by partially breaking a portion of the rotor core 40 shown on the lower side of the paper surface. The concave portion 36 is a concave groove provided over the inner circumferential side of the ring portion 28.

  The rotor body 22 is formed by connecting a shaft mounting portion 24, a disc portion 26, and a ring portion 28 to each other. The rotor body 22 is formed by molding an appropriate metal material into a predetermined shape. The shaft mounting part 24, the disk part 26, and the ring part 28 can be integrally formed by using cast iron as the metal material. Instead of integral molding, a plurality of members may be assembled into the rotor body 22.

  The rotor core 40 is an annular magnetic body including a plurality of permanent magnets 42 that form the magnetic poles of the outer rotor structure 20. The rotor core 40 is fixed by being fitted into the recess 36 for arranging the rotor core of the ring portion 28. As a method for fixing the rotor core 40 to the recess 36 for arranging the rotor core of the ring portion 28, a press-fitting method, a shrink fitting method, an adhesion method, or the like is used.

  The rotor core 40 is a laminated body in which a predetermined number of magnetic thin plates are laminated. As a material of the magnetic thin plate, an electromagnetic steel plate which is a kind of silicon steel plate can be used. Instead of the laminated body of magnetic thin plates, the rotor core 40 may be formed by integrally molding magnetic powder.

  The rotor core 40 is provided with a predetermined number of magnetic poles in the circumferential direction. The number of magnetic poles is determined by the specifications of the second rotating electrical machine 14. A magnet hole is provided in a fan-shaped portion obtained by dividing the rotor core 40 by the number of magnetic poles. A permanent magnet 42 forming a magnetic pole is inserted into the magnet hole, and the magnet hole and the permanent magnet 42 are fixed by a magnet fixing member. As the magnet fixing member, an insulating resin is used. For example, an epoxy resin can be used.

  The permanent magnet 42 is a rod-shaped magnet extending in the axial direction, and one permanent magnet 42 is disposed in each magnet hole. The length of the permanent magnet 42 in the axial direction is preferably the same as or slightly shorter than the length of the rotor core 40 in the axial direction, and it is preferable that the permanent magnet 42 does not protrude from the axial end surface of the rotor core 40. The direction of magnetization of the permanent magnet 42 is performed so that the rotor core 40 is in a radial direction in a state where the rotor core 40 is disposed in the recess 36, and the magnetization direction is mutually between magnetic poles adjacent to each other along the circumferential direction of the rotor core 40. Arranged to be reversed. For example, the polarities of the magnetic poles facing the inner circumferential side are arranged in the order of N, S, N, S,.

  As the material of the permanent magnet 42, rare earth magnets such as neodymium magnets mainly composed of neodymium, iron and boron, and samarium cobalt magnets mainly composed of samarium and cobalt are used. Besides this, a ferrite magnet, an alnico magnet, or the like may be used.

  In FIG. 2, the embedded magnet type in which the permanent magnet 42 forming the magnetic pole is embedded in the rotor core 40 has been described. However, the permanent magnet 42 may be exposed on the inner peripheral wall of the rotor core 40. The rotor core 40 may be a reluctance type magnetic pole whose reluctance changes along the circumferential direction. A change in reluctance and the permanent magnet 42 may be used in combination.

  In FIG. 2, the gear portion 50 provided on the outer peripheral surface of the ring portion 28 engages the second rotating electrical machine 14 and the gear reduction mechanism 16, and the power generated by the outer rotor structure 20 in cooperation with the stator 8. Is a mechanical element that transmits to the gear reduction mechanism 16. The gear part 50 can be comprised with a spline.

  A “spline” is a mechanical element that transmits power while displacing a displacement that occurs in the axial direction when rotating shafts are connected. In order to transmit power while escaping the displacement generated in the axial direction, tooth-like grooves having a fitting relationship with each other are provided on the outer circumferences of the rotating shafts that transmit power.

  In the case of FIG. 2, the gear 19 of the gear train constituting the gear reduction mechanism 16 and the annular ring portion 28 of the second rotating electrical machine 14 correspond to two rotating shafts connected in a “spline”. To do. Therefore, hereinafter, the gear portion 50 provided on the outer peripheral surface of the ring portion 28 is referred to as a spline 50 unless otherwise specified. The spline 50 is a tooth-like groove provided on the annular outer periphery of the ring portion 28, and has a relationship of fitting with the tooth-like groove of the gear 19. The tooth-like groove of the spline 50 and the tooth-like groove of the gear 19 in the second rotating electrical machine 14 can be fitted and engaged with each other, and power can be transmitted while escaping the displacement generated in the axial direction. Due to the engagement with the gear 19 and the power transmission via the spline 50, the second rotating electrical machine 14 is restrained from being displaced along the radial direction of the ring portion 28 due to the centrifugal force during the operation, so that the second rotation The deviation of the central axis of the electric machine 14 is suppressed.

  The effects of the above configuration will be described more specifically with reference to FIGS. FIG. 3 is a view corresponding to FIG. 1 and showing a transaxle 11 of a comparative example. Comparing FIG. 3 with FIG. 1, in the second rotating electrical machine 15, the rotor shaft 34 extends in the axial direction and includes a gear 52 at the tip thereof. The gear 52 meshes with the gear 19 of the gear reduction mechanism 16. FIG. 4 is a view corresponding to FIG. 2 and showing an outer rotor structure 21 of a comparative example. When FIG. 4 is compared with FIG. 2, the spline 50 is not provided on the outer periphery of the ring portion 28 in the rotor body 23. Instead, as indicated by a two-dot chain line, the rotor shaft 34 extends to the other side along the axial direction, the gear 52 is attached to the tip thereof, and the tooth-like groove of the gear 52 is the gear 19 of the gear reduction mechanism 16. Are engaged with each other in a tooth-like groove. Thereby, power transmission can be performed between the gear 52 and the gear 19 while escaping the axial displacement.

  In the outer rotor structure 21, power transmission to the gear reduction mechanism 16 is performed by the gear 52, and power transmission to the gear reduction mechanism 16 is not performed on the outer periphery of the ring portion 28. Accordingly, when the second rotating electrical machine 15 is operated, the ring portion 28 is displaced in the radial direction by the centrifugal force as indicated by the white arrows 60 and 62. When this displacement differs along the circumferential direction as indicated by the size of the white arrows 60 and 62, the central axis of the second rotating electrical machine 15 is displaced as indicated by the white arrow 70. On the other hand, in the outer rotor structure 20 including the spline 50, the displacement along the radial direction of the ring portion 28 due to the centrifugal force during operation is suppressed by the engagement with the gear 19 and the power transmission via the spline 50. The As a result, the shift of the central axis of the second rotating electrical machine 14 and the stress generated therewith are suppressed. Further, since the gear 52 can be omitted in the transaxle 10 as compared with the transaxle 11, the number of gears can be reduced as a whole.

  The outer rotor structure 20 of the rotating electric machine having the above-described structure is an outer rotor structure of the rotating electric machine in the transaxle 10 having two rotating electric machines 12 and 14 and a gear reduction mechanism 16 arranged on multiple axes. The outer rotor structure 20 includes a rotor body 22 and a rotor core 40. The rotor body 22 includes a shaft mounting portion 24 for mounting a rotor shaft extending in the axial direction, a disk portion 26 projecting radially from the shaft mounting portion 24 toward the outer peripheral side, and an axial direction on the outer periphery of the disk portion 26. Includes a ring portion 28 projecting in an annular shape. The ring portion 28 has a concave portion 36 for arranging the rotor core on the inner peripheral side. The rotor core 40 is disposed in the concave portion 36 for arranging the rotor core of the ring portion 28 and has an annular shape provided with a predetermined number of magnetic poles in the circumferential direction. The outer rotor structure 20 further includes a spline 50 provided on the outer peripheral surface of the ring portion 28 for engagement with the gear reduction mechanism 16.

  With the above configuration, the radial displacement is restricted by the gear reduction mechanism 16 in which the outer peripheral surface of the annular ring portion 28 on the outer periphery of the rotor body 22 is engaged through the spline 50, and the deviation of the rotor central axis is suppressed. Is done. As a result, the displacement of the central axis of the rotor due to centrifugal force during operation and the stress generated therewith can be suppressed, and the output torque of the rotating electrical machine 14 is improved. Further, when the output of the rotating electrical machine is increased and the size thereof is increased, a relatively simple means for providing a spline can make the structure robust against the deviation of the central axis of the rotor.

  8 Stator, 10, 11 Transaxle, 12, 14, 15 Rotating electrical machine, 16 Gear reduction mechanism, 18 Power distribution mechanism, 19, 52 Gear, 20, 21 Outer rotor structure, 22, 23 Rotor body, 24 Shaft mounting portion, 26 Disk part, 28 Ring part, 30 Open space part, 32 Shaft mounting hole, 34 Rotor shaft, 36 Recessed part, 40 Rotor core, 42 Permanent magnet, 50 Spline (gear part), 60, 62, 70 White arrow.

Claims (1)

An outer rotor structure of a rotating electric machine in a transaxle having two rotating electric machines and a gear reduction mechanism arranged on a double shaft,
A shaft mounting portion for mounting the rotor shaft extending in the axial direction, a disk portion projecting radially from the shaft mounting portion toward the outer peripheral side, and an inner periphery projecting in an annular shape in the axial direction on the outer periphery of the disk portion A rotor body including a ring portion having a recess for rotor core arrangement on the side;
A rotor core having an annular shape that is disposed in the concave portion for arranging the rotor core of the ring portion and provided with a predetermined number of magnetic poles in the circumferential direction;
A spline provided on the outer peripheral surface of the ring portion for engagement with the gear reduction mechanism;
An outer rotor structure for a rotating electrical machine.

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