JP2018113741A - Rotary electric machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve reliability of a rotary electric machine by suppressing axial movements of a stator holder and a stator at high temperature.SOLUTION: A rotary electric machine comprises: a rotor; an iron stator which is disposed while facing the rotor with a cavity interposed therebetween; an aluminum housing in which the rotor and the stator are accommodated; and a stator holder including a cylindrical part which is fitted to an outer peripheral surface of the stator. Projections that are formed on an outer peripheral surface of the stator holder include portions that become discontinuous at least partially in a motor axis direction.SELECTED DRAWING: Figure 2

Description

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

  2. Description of the Related Art Conventionally, there has been known a motor unit that includes a motor having a stator around which a coil is wound, a rotor disposed inside the stator, and a housing in which the motor is housed.

  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 coefficient differs between iron and aluminum, the stator is supported and fixed to the housing by shrink fitting instead of press fitting.

  However, when shrink-fitting the stator to the housing, it is necessary to secure a tightening allowance that takes into account the difference in linear expansion coefficient between iron and aluminum, and the inner peripheral surface of the housing and the outer peripheral surface of the stator must be polished with high accuracy There is.

  Therefore, there is a problem that it is expensive, for example, a shrink fitting device is required to shrink and fit the stator to the housing. In addition, when shrink fitting, the tightening allowance is relatively large, and there is a problem that the influence (iron loss) on the magnetic circuit due to the compressive stress becomes large.

  Therefore, in order to solve such a problem, a device in which a stator holder is provided between the stator and the housing has been proposed.

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

  However, the housing structure described in Patent Document 1 does not have sufficient countermeasures against displacement of the stator holder and the stator in the direction of the rotating shaft at high temperatures.

JP 2011-101513 A

  An object of the present invention is to improve the reliability of a rotating electrical machine by suppressing axial movement of the stator holder and the stator at high temperatures.

  A rotating electrical machine according to the present invention includes a rotor, an iron stator disposed facing the rotor via a gap, an aluminum housing in which the rotor and the stator are accommodated, 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 with respect to the motor axial direction.

  According to the present invention, the reliability of the stator holder and the stator at a high temperature is improved.

2 is a schematic cross-sectional view of the rotary electric machine 1 along the direction of the rotation axis. It is sectional drawing in the case from the arrow direction of the AA line of FIG. It is a perspective view of the stator holder 40 in 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 cross-sectional view of the rotating electrical machine 1 along the rotational axis direction. FIG. 2 is a cross-sectional view taken from the direction of the arrow AA in FIG. The rotating electrical machine 1 in this embodiment is a rotating electrical 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 axial end side of the housing 10. The rear bracket 50 is fastened to the other axial end of the housing 10. The interior 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 side of the shaft 31 of the rotating electrical machine 1.

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

  A boss portion 53 that protrudes toward one end in the axial direction is formed at the center of the diameter of the rear bracket 50. A through hole 54 that extends in the axial direction and penetrates the rear bracket 50 is formed in the central portion in the radial direction of the boss portion 53. The shaft 31 is inserted through the through hole 54 into the sensor chamber 55 and the other of the shaft 31. 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 electrical machine 31 can be detected by detecting the rotation angle of the shaft 31 with the rotation sensor 52 disposed in the sensor chamber 55.

  The housing 10 is formed in a substantially cylindrical shape so as to cover the entire components of the rotating electrical machine 1 excluding 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 electrical 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 the entire outer peripheral surface 20a is provided. The cylindrical portion 41 is formed in a size that allows the stator 20 to be shrink-fitted and fixed. The stator holder 40 is made of, for example, an iron-based material, and the stator 20 is shrink-fitted and fixed to the inner peripheral surface 41 a of the stator holder 40.

  The stator holder 40 has a protrusion 42 formed on the outer peripheral surface 41 b of the cylindrical portion 41. The protrusions 42 are formed on the outer peripheral surface 41b of the stator holder 40, for example, in which a large number are regularly aligned along the axial direction, but the alignment is discontinuous at some or a plurality of portions. .

  Alternatively, as shown in FIG. 3, a plurality of projections 42 having undercut portions 43 are irregularly formed. Furthermore, the protrusion 42 is widened from the outer peripheral surface 41b toward the radially outer side as viewed from the inner diameter side of the stator holder 40. That is, the undercut portion 43 is formed on the protrusion 42. Thus, by forming the protrusion 42 on the stator holder 40, 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 that is formed larger than the root portion.

  The protrusion 42 is formed so as to overlap the flow path 11 when viewed from the radial direction of the rotating electrical machine 1, and the tip of the protrusion 42 extends to the vicinity of the flow path 11.

  The stator holder 40 is integrated with the housing 10. That is, aluminum constituting the housing 10 is filled between two adjacent protrusions 42 of the stator holder 40. In order to integrate the stator holder 40 and the housing 10 in this way, the stator holder 40 is first manufactured, and then aluminum is cast on the outer periphery of the stator holder 40 so as to enclose the stator holder 40, thereby manufacturing the housing 10. That's fine.

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

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

  Subsequently, for example, an iron steel plate is cut into the same shape as the stator core 21 to manufacture a plurality of stator core pieces, and the stator core 21 is manufactured by stacking them. Then, the stator 20 is manufactured by winding the coil 22 around the stator core 21.

  Subsequently, the housing 10 is manufactured. Specifically, aluminum is cast on the outer periphery of the stator holder 40 so as to contain the stator holder 40, and the housing 10 is manufactured so that the stator holder 40 is integrated.

  Subsequently, the stator 20 is press-fitted and fixed to the inner peripheral surface 41 a of the stator holder 40. Specifically, the stator 20 is inserted into the stator holder 40 by shrink fitting into the inner peripheral surface 41a of the stator holder 40, and the stator 20 is inserted to a predetermined position. Thereby, the inner peripheral surface 41a of the stator holder 40 and the outer peripheral surface 20a of the stator 20 are in close contact with each other without a gap.

  And the assembly of a motor unit is completed by arrange | positioning the rotor 30 by which the shaft 31 was penetrated to the inner peripheral side of the stator 20. FIG.

  Since the stator holder 40 and the housing 10 are integrated and the protrusion 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 electrical 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, the linear expansion coefficient is different because the stator holder 40 and the housing 10 are different materials. However, even if the temperature changes, the stator holder 40 and the housing 10 are displaced by the protrusion 42 or between the stator holder 40 and the housing 10. It is possible to prevent a gap from being formed on the surface. Therefore, it is possible to suppress changes in torque holding characteristics and cooling characteristics of the stator holder depending on the temperature.

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

  Further, since the protrusions 42 are formed on the outer peripheral surface 41 a 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 cooled more effectively via the stator holder 40.

  The top surface of the protrusion 41b on the outer peripheral surface of the cylindrical portion 41 of the stator holder 40 is disposed in the vicinity of the water jacket 11 that is a refrigerant passage, whereby the cooling effect by the flow path 11 can be improved, and the stator holder The stator 20 can be more effectively cooled via the connector 40.

  Further, by making the stator holder 40 made of iron, it is possible to reduce the fastening allowance due to the stator shrinkage, and it is possible to reduce the iron loss caused by the compressive stress due to the fastening allowance.

DESCRIPTION OF SYMBOLS 1 ... Rotary 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 part 41a ... Inner peripheral surface 41b ... Outer peripheral surface 42 ... Protrusion 43 ... Undercut part 50 ... Rear bracket 51 ... Motor chamber 52 ... Rotation sensor 53 ... Boss part 54 ... Through hole, 55 ... sensor chamber, 60 ... front bracket, 61 ... through hole

Claims (5)

A rotor,
An iron stator disposed opposite to the rotor via a gap;
An aluminum housing in which the rotor and the stator are housed;
A stator holder having a cylindrical portion fitted to the outer peripheral surface of the stator,
A rotating electrical machine in which the protrusion formed on the outer peripheral surface of the stator holder has a portion at least partially discontinuous with respect to the motor axial direction. The rotating electrical machine according to claim 1,
The housing is a rotating electrical machine that forms a flow path through which a refrigerant flows. A rotating electrical machine according to claim 2,
The rotating electrical machine is formed at a position where the flow path overlaps with the protrusion when viewed from the radial direction. The rotating electrical machine according to any one of claims 1 to 3,
The said protrusion is a rotary electric machine comprised by the base part by the side of the said stator holder, and the edge part formed larger than the said base part. The rotating electrical machine according to any one of claims 1 to 4,
The stator holder is a rotating electric machine made of an iron-based material.

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