JP6655560B2 - Rotating electric machine - Google Patents

Description

The present invention relates to a rotating electric machine, and more particularly to a rotating electric machine that generates a driving force for a vehicle.

  BACKGROUND ART Conventionally, a motor unit including a motor having a stator on which a coil is wound and a rotor disposed inside the stator, and a housing containing the motor is known.

  In such a motor unit, an iron stator, which is a magnetic material, and an aluminum housing are often used to reduce the weight. In this case, since the linear expansion coefficients of iron and aluminum are different, the method of supporting and fixing the stator to the housing is not press-fitting but is supported and fixed by shrink fitting.

  However, when shrink-fitting the stator to the housing, it is necessary to secure a margin in consideration of the difference in linear expansion coefficient between iron and aluminum, and it is necessary to grind the inner peripheral surface of the housing and the outer peripheral surface of the stator with high precision. There is.

  Therefore, there is a problem that it is costly to shrink-fit the stator to the housing to support and fix the stator, which requires a device for shrink-fitting. Further, when shrink fitting is performed, the interference is relatively large, so that there is a problem in that the influence (iron loss) on the magnetic circuit due to the compressive stress increases.

  In order to solve such a problem, there has been proposed an arrangement in which a stator holder is provided between a stator and a housing.

  Patent Literature 1 describes an aluminum housing in a housing structure of a rotating machine. The rotating electric machine described in Patent Document 1 includes a rotor, an iron stator provided to cover an outer peripheral surface of the rotor, an aluminum housing in which the rotor and the stator are housed, and an outer periphery of the stator. A stator having a cylindrical portion fitted to a surface of the housing, wherein a projection having an undercut portion is formed on an outer peripheral surface of the cylindrical portion radially outward, and Covers the outer peripheral surface of the stator holder, is in close contact with the outer surface of the projection including the undercut portion, and is coupled to the stator holder.

  However, in the housing structure described in Patent Literature 1, measures against displacement of the stator holder and the stator in the direction of the rotating shaft at a high temperature are not sufficient.

JP 2011-101513 A

  An object of the present invention is to suppress the axial movement of a stator holder and a stator at a high temperature and improve the reliability of a rotating electric machine.

  A rotating electric machine according to the present invention includes: a rotor; an iron stator disposed to face the rotor with a gap therebetween; an aluminum housing accommodating the rotor and the stator; and an outer peripheral surface of the stator. And a protrusion formed on the outer peripheral surface of the stator holder has a portion that is at least partially discontinuous in the motor axial direction.

  An object of the present invention is to improve the reliability of a stator holder and a stator at a high temperature.

FIG. 2 is a schematic cross-sectional view of a configuration of the rotating electric machine 1 along a rotation axis direction. It is sectional drawing in the case of the arrow of the AA line of FIG. FIG. 3 is a perspective view of a stator holder 40 according to the embodiment of the present invention.

  An embodiment according to the present invention will be described with reference to FIGS.

  FIG. 1 is a schematic configuration cross-sectional view of the rotating electric machine 1 along a rotation axis direction. FIG. 2 is a cross-sectional view when viewed from the direction of the arrow AA in FIG. The rotating electric machine 1 in the present embodiment is a rotating electric machine for driving a vehicle.

  The stator 20 has a stator core 21 around which a coil 22 is wound. The rotor 30 forms a storage space for storing the permanent magnet 34. The front bracket 60 is fastened to one end of the housing 10 in the axial direction. The rear bracket 50 is fastened to the other axial end of the housing 10. The inside of the housing 10 functions as a motor chamber 51.

  One end of the shaft 31 is held by the front bracket 60, and the other end is held by the rear bracket 50. The front bracket 60 is formed with a through hole 61 penetrating in the thickness direction. The through hole 61 is provided with a bearing 32b that rotatably supports one end of the shaft 31 of the rotary electric machine 1.

  The rotation sensor 52 detects the rotation of the shaft 31 and is stored in the rear bracket 50.

  A boss 53 projecting toward one end in the axial direction is formed at the center of the diameter of the rear bracket 50. A through hole 54 is formed in the center of the boss 53 in the radial direction and extends through the rear bracket 50 in the axial direction. The end side is arranged. The through hole 54 is provided with a bearing 32a that rotatably supports the other end of the shaft 31.

  The rotation angle of the rotating electric machine 31 can be detected by detecting the rotation angle of the shaft 31 by the rotation sensor 52 arranged in the sensor chamber 55.

  The housing 10 is formed in a substantially cylindrical shape so as to cover all components of the rotary electric machine 1 except the housing 10. The housing 10, the front bracket 60 and the rear bracket 50 are formed by casting aluminum. In the housing 10, a flow path 11 for cooling the entire rotating electric machine 1 around the stator 20 is provided over the entire circumference along the circumferential direction of the stator 20.

  On the outer peripheral surface 20a of the stator 20, a stator holder 40 having a cylindrical portion 41 formed so as to cover substantially the entire outer peripheral surface 20a is provided. The cylindrical portion 41 is formed in a size that allows the stator 20 to be fixed by shrink fitting. The stator holder 40 is formed of, for example, an iron-based material, and the stator 20 is shrink-fitted and fixed to an inner peripheral surface 41 a of the stator holder 40.

  The stator holder 40 has a projection 42 formed on the outer peripheral surface 41b of the cylindrical portion 41. The projections 42 are formed on the outer peripheral surface 41 b of the stator holder 40, for example, many of which have a regularly aligned shape along the axial direction, but are formed such that the alignment is discontinuous at some or a plurality of portions. .

  Alternatively, as shown in FIG. 3, a plurality of protrusions 42 having undercut portions 43 are formed irregularly. Further, the projection 42 is widened radially outward from the outer peripheral surface 41b when viewed from the inner side of the stator holder 40. That is, the undercut portion 43 is formed on the protrusion 42. By forming the projections 42 on the stator holder 40 in this manner, the surface area of the outer peripheral surface 41b of the stator holder 40 can be increased. The undercut portion 43 includes a root portion on the stator holder 40 side and an end portion formed to be larger than the root portion.

  The projection 42 is formed so as to overlap the flow channel 11 when viewed from the radial direction of the rotary electric machine 1, and the tip of the projection 42 extends to the vicinity of the flow channel 11.

  The stator holder 40 is integrated with the housing 10. That is, between the two adjacent projections 42 of the stator holder 40, the aluminum constituting the housing 10 is filled. In order to integrate the stator holder 40 and the housing 10 in this manner, first, the stator holder 40 is manufactured, and then, aluminum is cast around the outer periphery of the stator holder 40 so as to include the stator holder 40, and the housing 10 is manufactured. I just need.

  Next, a method of assembling the motor unit of the stator 20 and the rotor 30 including the stator holder 40 will be described.

  First, the above-described stator holder 40 is manufactured in advance.

  Subsequently, a plurality of stator core pieces are manufactured by cutting, for example, an iron steel plate into the same shape as the stator core 21, and the stator core 21 is manufactured by stacking them. Then, the coil 20 is wound around the stator core 21 to manufacture the stator 20.

  Subsequently, the housing 10 is manufactured. Specifically, aluminum is cast around the outer periphery of the stator holder 40 so as to include the stator holder 40, and the housing 10 is manufactured so as to integrate the stator holder 40.

  Subsequently, the stator 20 is press-fitted and fixed to the inner peripheral surface 41a of the stator holder 40. Specifically, the stator 20 is inserted into the stator holder 40 by shrink fitting on the inner peripheral surface 41a of the stator holder 40, and the stator 20 is inserted to a predetermined position. As a result, the inner peripheral surface 41a of the stator holder 40 and the outer peripheral surface 20a of the stator 20 come into close contact with no gap.

  Then, by disposing the rotor 30 with the shaft 31 inserted through the inner peripheral side of the stator 20, assembly of the motor unit is completed.

  Since the stator holder 40 and the housing 10 are integrated, and the projection 42 having the undercut portion 43 is formed on the outer peripheral surface 41a of the cylindrical portion 41 of the stator holder 40, the temperature changes when the rotating electric machine 1 is driven. However, it is possible to prevent a gap from being formed between the stator holder 40 and the housing 10.

  That is, although the linear expansion coefficient is different due to the different materials of the stator holder 40 and the housing 10, even if the temperature changes, the protrusion 42 causes the stator holder 40 and the housing 10 to be displaced from each other, or Gaps can be prevented. Therefore, it is possible to suppress the torque holding characteristic and the cooling characteristic of the stator holder from changing with temperature.

  The alignment of the projections 42 on the outer peripheral surface of the cylindrical portion 41 of the stator holder 40 is partially or discontinuously formed at a plurality of portions, so that the stator holder 40 can be moved not only in the outer peripheral direction but also in the axial direction with respect to the housing 10. Can also be held.

  Further, since the projections 42 are formed on the outer peripheral surface 41a of the cylindrical portion 41 of the stator holder 40, the surface area of the outer peripheral surface of the stator holder 40 can be increased. Therefore, the cooling effect by the flow path 11 can be improved, and the stator 20 can be more effectively cooled through the stator holder 40.

  Since the top surface of the projection 41b on the outer peripheral surface of the cylindrical portion 41 of the stator holder 40 is disposed near the water jacket 11 which is a passage for the refrigerant, the cooling effect by the flow path 11 can be improved, and the stator holder can be improved. The stator 20 can be cooled more effectively through the connection 40.

  In addition, since the stator holder 40 is made of iron, the interference due to the stator shrink fitting can be reduced, and the iron loss generated by the compressive stress due to the interference can be reduced.

DESCRIPTION OF SYMBOLS 1 ... Rotating electric machine, 10 ... Housing, 11 ... Flow path, 20 ... Stator, 21 ... Stator core, 22 ... Coil, 30 ... Rotor, 31 ... Shaft, 32a ... Bearing, 32b ... Bearing, 34 ... Permanent magnet, 40 ... Stator Holder, 41: cylindrical portion, 41a: inner peripheral surface, 41b: outer peripheral surface, 42: projection, 43: undercut portion, 50: rear bracket, 51: motor chamber, 52: rotation sensor, 53: boss portion, 54 ... Through hole, 55: Sensor chamber, 60: Front bracket, 61: Through hole

Claims (4)

Rotor and
An iron stator arranged to face the rotor with a gap therebetween,
An aluminum housing in which the rotor and the stator are housed;
Have a cylindrical portion which is fitted to the outer peripheral surface of the stator, and a stator holder is formed integrally with the housing,
The protrusions formed on the stator holder outer circumferential surface, have a portion where alignment is discontinuous in the axial direction of the motor part or more sites,
The protrusion has a root portion on the stator holder side and an end formed to be larger than the root portion.
And a rotating electric machine constituted by the parts . The rotating electric machine according to claim 1, wherein
The housing is a rotating electric machine that forms a flow path through which a refrigerant flows. The rotating electric machine according to claim 2, wherein
A rotating electric machine wherein the flow path is formed at a position overlapping the projection when viewed from a radial direction. Be any rotating electric machine as claimed in claims 1 to 3,
The rotating electric machine wherein the stator holder is made of an iron-based material.

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