JP2015224601A - Electric supercharger - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electric supercharger which enables simplification of a cooling structure of a bearing and increase of the strength of housing which holds a stator.SOLUTION: An electric supercharger 101 includes: an electric motor 30 having a rotor 31 which may rotate and a stator 34 which is disposed so as to enclose the rotor 31 and fixed; a compressor wheel 21 which is connected with the rotor 31 so as to integrally rotate with the rotor 31; and a housing 10 which houses the rotor 31 and the stator 34. The housing 10 includes: a side wall 13a which encloses and holds the stator 34; and multiple heat radiation ribs 40 which protrude to the outer side at the exterior side of the side wall 13a. The multiple heat radiation ribs 40 include: first ribs 41 provided at a first portion 13a1 of the side wall 13a which holds the stator 34; and second ribs 42 provided at a second portion 13a2 of the side wall 13a which does not hold the stator 34. The first ribs 41 are formed so as to have strength higher than that of the second ribs 42.

Description

  The present invention relates to an electric supercharger.

  As described in Patent Document 1, there is an electric supercharger that includes a rotating electric machine and rotationally drives a compressor wheel using a driving force of the rotating electric machine. In the electric supercharger described in Patent Document 1, a compressor wheel and a turbine wheel are connected to both ends of a shaft that extends through a cylindrical housing. A rotor and a stator for rotationally driving the shaft are provided in the housing. The rotor is fixed to the shaft so as to rotate integrally, and the shaft is rotatably supported by two bearings provided on the wall portion of the housing. The stator is fixed to the housing. The compressor wheel and the shaft are rotationally driven by selecting and using the exhaust gas acting to rotate the turbine wheel and the rotational driving force of the rotating electrical machine according to the situation.

  The two bearings respectively transmit heat of exhaust gas from the turbine wheel side and heat of compressed air from the compressor wheel side. Further, the shaft itself rotates at a high speed together with the compressor wheel and the turbine wheel, so that the bearing itself generates heat. When the bearing generates heat excessively, its slidability, durability, and the like deteriorate. Therefore, the electric supercharger disclosed in Patent Document 1 is configured such that a cooling lubricant is supplied to the bearing.

JP 2008-128112 A

  However, the electric supercharger described in Patent Document 1 requires a passage, piping, and a pump for supplying and circulating the lubricating oil to the bearing, so that the structure becomes complicated and the cost increases. There is. Further, the cylindrical stator of the rotating electric machine is usually attached by being closely fitted to the cylindrical wall portion of the housing so as not to move, and the housing is fixed by tightening the stator. When the temperature of the housing changes, the tightening force of the housing with respect to the stator changes. However, when the temperature is low, the tightening force becomes too strong, and the strength of the housing wall portion may be insufficient and may be damaged.

  The present invention has been made to solve the above problems, and provides an electric supercharger that simplifies the bearing cooling structure and increases the strength of the housing that holds the stator (stator). Objective.

  In order to solve the above-described problems, an electric supercharger according to the present invention includes a rotating electric machine having a rotatable rotor and a stator that is disposed and fixed so as to surround the rotor, and the rotor integrally. A compressor wheel coupled to rotate; and a housing that houses the rotor and the stator, the housing surrounding and holding the stator, and projecting outwardly outside the wall. A plurality of ribs, and the plurality of ribs are provided at a first rib provided at the first portion for holding the stator in the wall portion and at a second portion at which the stator at the wall portion is not held. The first rib is formed to have higher strength than the second rib.

The first rib may have a larger cross section than the second rib.
The electric supercharger includes, in a housing, a first bearing and a second bearing that rotatably support the rotating shaft of the rotor, and the first bearing is disposed between the compressor wheel and the second bearing, The first rib may be provided from the first bearing to the stator in the axial direction of the rotating shaft, and the second rib may be provided from the stator to the second bearing in the axial direction of the rotating shaft.
The housing has a rib coupling portion integrally formed with the first rib so as to at least partially connect the adjacent first ribs, and the rib coupling portion passes through a fastening member for attaching the electric supercharger. There may be provided fastening holes.
A 1st rib and a 2nd rib may extend along the circumferential direction of a rotating shaft on a wall part.

  According to the electric supercharger according to the present invention, the bearing cooling structure can be simplified and the strength of the housing holding the stator can be increased.

It is the schematic diagram which looked at the cross section of the horizontal direction of the electric supercharger which concerns on embodiment of this invention from upper direction. It is the typical top view which looked at the electric supercharger of FIG. 1 from upper direction. It is the typical side view which looked at the electric supercharger of FIG. 1 from the side.

Embodiments Hereinafter, an electric supercharger according to embodiments of the present invention will be described with reference to the accompanying drawings.
Referring to FIG. 1, an electric supercharger 101 according to an embodiment of the present invention includes a supercharging unit 1 for supercharging sucked gas (in the present embodiment, air), and a supercharging unit 1 And a drive unit 2 for driving the motor using an electric motor 30 which is a rotating electrical machine. The electric supercharger 101 is mounted on, for example, a vehicle equipped with a fuel cell that requires air supply without mounting an internal combustion engine, and supercharges air and supplies it to the fuel cell.

  The supercharging unit 1 includes a compressor wheel 21 that supercharges intake air by rotating, a shaft 22 that can rotate integrally with the compressor wheel 21, and a compressor cover 11 that houses the compressor wheel 21 by being assembled with each other. And a seal plate 12. The compressor cover 11 and the seal plate 12 are made of a metal such as an aluminum alloy. Here, the shaft 22 constitutes a rotation axis.

The shaft 22 extends from the inside of the compressor cover 11 to the drive unit 2 through the seal plate 12. At this time, the seal plate 12 extends in the radial direction of the shaft 22.
Inside the compressor cover 11 and the seal plate 12 are a wheel chamber 15 that rotatably accommodates the compressor wheel 21 and a suction passage 16 that extends from the wheel chamber 15 in the axial direction of the shaft 22 and opens to the outside. And an annular discharge passage 17 that communicates with the wheel chamber 15 and extends around the compressor wheel 21 and opens to the outside.

  The drive unit 2 includes a bottomed cylindrical motor case 13 and an end cover 14 that closes the opening of the motor case 13. The motor case 13 and the end cover 14 are made of a metal such as an aluminum alloy. The motor case 13 and the end cover 14 form a motor chamber 18 that houses the electric motor 30 therein.

The compressor cover 11 and the seal plate 12 have the same outer diameter in the radial direction of the shaft 22. The outer diameter of the compressor cover 11 and the seal plate 12 is larger than the outer diameter of the end cover 14 in the radial direction of the shaft 22. Is also significantly larger.
The compressor cover 11, the seal plate 12, the motor case 13, and the end cover 14 form a housing 10 for the electric supercharger 101.

The motor case 13 includes a cylindrical side wall 13a and an end wall 13b that forms a bottom portion that closes an end of the side wall 13a. The end cover 14 closes the opening of the side wall 13a. A seal plate 12 is fixed to an end wall 13 b extending in the radial direction of the shaft 22. An end wall through hole 13b1 that opens toward the motor chamber 18 and the seal plate 12 is formed through the center of the end wall 13b.
The seal plate 12 is formed with a plate through hole 12a that is adjacent to and communicates with the end wall through hole 13b1.
The shaft 22 extends into the motor chamber 18 through the plate through hole 12a and the end wall through hole 13b1. The shaft 22 extends in the axial direction along the axial direction of the side wall 13 a of the motor case 13.

  An outer peripheral surface 22 a of the shaft 22 is supported by a first bearing 23 and a second bearing 24 such as a ball bearing provided in the motor chamber 18 so as to be rotatable in the circumferential direction. The first bearing 23 supports the shaft 22 near the end wall 13b, and the second bearing 24 supports the shaft 22 near the end 22b on the end cover 14 side.

The first bearing 23 has a cylindrical shape with a flange surrounding the outer periphery thereof, is supported and fixed by a first bearing frame 25 fixed to the end wall 13b, and is positioned adjacent to the end wall through hole 13b1. The first bearing 23 has an outer diameter larger than the inner diameter of the end wall through hole 13b1, and closes the end wall through hole 13b1.
The second bearing 24 has a cylindrical shape with a flange surrounding the outer periphery thereof, and is supported and fixed by a second bearing frame 26 fixed to the end cover 14.

  A cylindrical rotor core 32 is provided on the outer peripheral surface 22 a of the shaft 22 so as to rotate integrally with the shaft 22 between the first bearing 23 and the second bearing 24 in the motor chamber 18. A permanent magnet 33 is embedded in the rotor core 32 along the outer peripheral surface thereof. The rotor core 32 and the permanent magnet 33 constitute a rotor 31 that is a rotor.

  Further, a cylindrical stator core 35 is provided in the motor chamber 18 so as to surround the outer periphery of the rotor core 32. The stator core 35 is fixed to the side wall 13 a of the motor case 13. Further, a winding is wound in the stator core 35, and this winding forms a coil 36 and protrudes from both ends of the stator core 35. The stator core 35 and the coil 36 constitute a stator 34 that is a stator.

  The stator core 35 at normal temperature has an outer diameter that is slightly larger than the inner diameter of the inner peripheral surface 13aa of the side wall 13a of the motor case 13 at normal temperature, and is shrink-fitted onto the side wall 13a of the motor case 13. Fixed. Specifically, the side wall 13a of the motor case 13 is warmed, whereby the side wall 13a is thermally expanded so as to expand the inner diameter of the inner peripheral surface 13aa. Further, inside the thermally expanded side wall 13a, the stator core 35 including the coil 36 is inserted to a predetermined position in contact with the protrusion 13ab formed on the inner peripheral surface 13aa, and then the heating of the side wall 13a is stopped, The temperature of the side wall 13a is returned to room temperature. As a result, the thermally expanded side wall 13a contracts so as to reduce the inner diameter and is fitted to the stator core 35 so as to be tightened from the outer periphery, and the stator core 35 is fixed.

  The shaft 22, the rotor 31, and the stator 34 as described above constitute an electric motor 30. The shaft 22 also serves as the rotation shaft of the compressor wheel 21 and the electric motor 30. When electric power is supplied to the winding, a rotating magnetic field is generated from the coil 36, and the rotor magnet 32 is rotationally driven together with the shaft 22 and the compressor wheel 21 by the action of the rotating magnetic field received by the permanent magnet 33.

  The end wall 13b of the motor case 13 is formed with a plurality of pressure adjusting holes 13b2 that open toward the motor chamber 18 and the seal plate 12. The pressure adjustment hole 13b2 allows the air in and out of the motor chamber 18 to enter and exit, and suppresses the pressure difference between the inside and outside of the motor chamber 18. Thereby, leakage of the grease enclosed in the first bearing 23 is prevented.

A plurality of heat radiating ribs 40 are integrally formed on the outer peripheral side of the cylindrical side wall 13a of the motor case 13 for improving the cooling efficiency of the motor case 13 by ambient air.
Each of the heat radiating ribs 40 has an annular plate shape that extends along the circumferential direction so as to surround the side wall 13a, and protrudes radially outward from the side wall 13a. The plurality of heat radiating ribs 40 are arranged in a line along the axial direction of the side wall 13 a and the shaft 22.

The plurality of heat radiating ribs 40 are formed in two types of shapes, and are constituted by a plurality of first ribs 41 and second ribs 42 having different shapes.
In the side wall 13 a, the first rib 41 is disposed at the first portion 13 a 1 between the end portion 35 a on the end cover 14 side of the stator core 35 and the seal plate 12, and the second rib 42 is the end portion 35 a of the stator core 35. And the end cover 14 is disposed in the second portion 13a2. The first portion 13a1 constitutes a portion that holds the stator core 35 in the side wall 13a, and the second portion 13a2 constitutes a portion that does not hold the stator core 35 in the side wall 13a.

The first rib 41 has an outer diameter close to the seal plate 12 without projecting radially outward from the seal plate 12.
The second rib 42 has an outer diameter close to that of the end cover 14 without projecting radially outward from the end cover 14.
Therefore, the first rib 41 has an outer diameter that is significantly larger than that of the second rib 42. Accordingly, the ribs 41 and 42 form a contour with a radial step, with the position of the end portion 35a of the stator core 35, which is a boundary between the plurality of first ribs 41 and the plurality of second ribs 42, as a boundary. .

In addition, the cylindrical end surface 41 a on the radially outer side of the first rib 41 has a larger thickness in the axial direction of the shaft 22 than the cylindrical end surface 42 a on the radially outer side of the second rib 42.
Further, on both sides of the end surface 41a of the first rib 41 in the axial direction of the shaft 22, tapered side surfaces 41b and 41c are formed so as to be inclined in the axial direction from the end surface 41a toward the side wall 13a. Yes. On both sides of the end surface 42a of the second rib 42 in the axial direction of the shaft 22, tapered side surfaces 42b and 42c are formed so as to be inclined from the end surface 42a toward the side wall 13a in the axial direction. The side surface 41b and the side surface 42b are parallel to each other, and the side surface 41c and the side surface 42c are parallel to each other.

The angle formed between the side surfaces 41b and 41c of the adjacent first rib 41, the angle formed between the side surface 41c of the adjacent first rib 41 and the side surface 42b of the second rib 42, and the adjacent second rib 42. The angles formed between the side surfaces 42b and 42c are the same, and are set so as to satisfy the draft angle of the mold used for casting the motor case 13.
Accordingly, the first rib 41 has an outer diameter and a thickness that are significantly larger than those of the second rib 42, that is, has a larger cross section in the axial direction and the radial direction of the shaft 22 than the second rib 42. ing. The second rib 42 is configured as described above, so that the axial length of the motor case 13 is shorter than when the second rib 42 has the same shape as the first rib 41.

  The 1st rib 41 which has the above structures has a contact area with the surrounding air significantly larger than the 2nd rib 42, and is provided with high heat dissipation. Further, the first rib 41 has high rigidity and strength, and extends around the side wall 13a around the stator core 35, thereby reinforcing the side wall 13a and increasing the strength and rigidity.

Moreover, in the motor case 13, the rib coupling | bond part 50 integrated so that two adjacent 1st ribs 41 may be connected partially is integrally molded.
1-3 together, the first rib 411 closest to the second rib 42 and the first rib 412 second closest to the second rib 42 are integrated so as to be partially connected. The 1st rib coupling part 51 which is one of the rib coupling parts 50 is formed. The first rib coupling portion 51 is integrally formed with the first ribs 411 and 412 and the side wall 13 a of the motor case 13 so as to fill a gap between the two first ribs 411 and 412. The first rib coupling portion 51 is partially formed along the circumferential direction with respect to the first ribs 411 and 412. The first rib coupling portion 51 includes a fastening hole 51 a extending in a tangential direction of the outer peripheral edge of the first ribs 411 and 412 and penetrating the first rib coupling portion 51 in the longitudinal direction, and an outer side of the first ribs 411 and 412. And a cylindrical outer peripheral surface 51b along the periphery.

  Further, the first rib 412 that is second closest to the second rib 42 and the first rib 413 that is third closest to the second rib 42 are integrated so as to be partially connected. A second rib coupling portion 52, which is the other of the two, is formed. The second rib coupling portion 52 is disposed on the opposite side of the first rib coupling portion 51 with the shaft 22 interposed therebetween. The second rib coupling portion 52 is integrally formed with the first ribs 412 and 413 and the side wall 13a so as to fill a gap between the two first ribs 412 and 413. The second rib coupling portion 52 is partially formed along the circumferential direction with respect to the first ribs 412 and 413. The second rib coupling portion 52 includes a fastening hole 52a extending in a tangential direction of the outer peripheral edge of the first ribs 412 and 413 and penetrating the second rib coupling portion 52 in the longitudinal direction, and an outer periphery of the first ribs 412 and 413. And a cylindrical outer peripheral surface 52b along the periphery. The fastening hole 52a is parallel to the fastening hole 51a.

Therefore, the first rib coupling portion 51 and the second rib coupling portion 52 increase the rigidity and strength of the first rib 41 and further increase the strength and rigidity of the side wall 13a.
Furthermore, the 1st rib coupling | bond part 51 and the 2nd rib coupling | bond part 52 comprise the attachment leg for attaching and fixing the electric supercharger 101 to an attachment target object. Further, the end cover 14 is integrally formed with a mounting foot 53 through which a fastening hole 53a parallel to the fastening holes 51a and 52a is formed.
After the electric supercharger 101 having the above-described configuration is positioned with respect to an attachment object (not shown), the fastening hole 51a of the first rib coupling portion 51, the fastening hole 52a of the second rib coupling portion 52, and the attachment A fastening member 54 such as a bolt is inserted into the fastening hole 53a of the foot 53, and the fastening member 54 is screwed into and tightened into the screw hole of the attachment object, thereby being fixed to the attachment object.

Moreover, the electric supercharger 101 as described above operates as described below.
Referring to FIG. 1, in the electric supercharger 101, when electric power is applied to the coil 36 of the electric motor 30 by a power source (not shown), the rotor 31 is rotationally driven by the rotating magnetic field generated by the coil 36, whereby the shaft 22 and the compressor wheel 21 are driven to rotate at high speed.

The compressor wheel 21 rotating at high speed compresses or supercharges the air sucked from the suction passage 16 and discharges it from the discharge passage 17.
At this time, the air that is heated by being compressed raises the temperature of the compressor wheel 21, the shaft 22, the compressor cover 11, and the seal plate 12. The heat transmitted from the shaft 22 and the seal plate 12 raises the temperature of the end wall 13b of the motor case 13 and the first bearing 23. Moreover, the temperature of the first bearing 23 and the second bearing 24 is increased by the rotation of the shaft 22. As a result, the first bearing 23 tends to be hotter than the second bearing 24.
Further, the coil 36 through which the current flows also generates heat, and the stator core 35 is heated.
Therefore, in the motor chamber 18, the temperature increases around the second bearing 24, the stator core 35, and the first bearing 23, and the temperatures are around the second bearing 24, around the stator core 35, and around the first bearing 23. It becomes high in order.

  Outside air is configured to be introduced around the electric supercharger 101, and the introduced outside air exchanges heat with the heat radiating rib 40 of the side wall 13 a of the motor case 13, so that the heat radiating rib 40 and the side wall are exchanged. Cool 13a. As a result, the air in the motor chamber 18 and the stator core 35 are cooled by exchanging heat with the side wall 13 a, and the cooled air cools the first bearing 23, the second bearing 24, the stator core 35, and the coil 36.

  In the heat dissipating rib 40, the first rib 41 has a larger outer diameter and thickness than the second rib 42, and thus has a larger contact area with respect to the surrounding air than the second rib 42. And has a large heat dissipation. For this reason, in the motor chamber 18, the internal air and the stator core 35 are sufficiently cooled by receiving a high cooling action in the region extending from the first bearing 23 to the stator core 35, and the internal air in the region extending from the stator core 35 to the second bearing 24. However, the cooling effect is lower than that in the region extending from the first bearing 23 to the stator core 35, but is sufficiently cooled. Thereby, the 1st bearing 23, the stator core 35, the coil 36, and the 2nd bearing 24 are fully cooled.

  In addition, in order to cool the internal air around the first bearing 23 and the stator core 35 having different temperature rising tendency via the side wall 13a and the first rib 41 of the motor case 13, the periphery of the first bearing 23 and the stator core 35 are cooled. There is a temperature difference in the internal air with the surroundings. Further, a temperature difference of the internal air is generated between the periphery of the stator core 35 and the periphery of the second bearing 24. As a result, an internal air flow (natural convection) along the axial direction of the shaft 22 occurs in the motor chamber 18, and this natural convection cools the first bearing 23, the stator core 35, the coil 36, and the second bearing 24. Increase efficiency.

  As described above, the electric supercharger 101 according to the embodiment of the present invention is integrated with the rotor 31 and the electric motor 30 having the rotatable rotor 31 and the stator 34 that is disposed and fixed so as to surround the rotor 31. The compressor wheel 21 is connected so as to rotate, and the housing 10 houses the rotor 31 and the stator 34. The housing 10 includes a side wall 13a of the motor case 13 that surrounds and holds the stator 34, and a plurality of heat radiating ribs 40 that protrude outwardly outside the side wall 13a. The plurality of heat dissipating ribs 40 include a first rib 41 provided in the first portion 13a1 that holds the stator 34 in the side wall 13a, and a second rib 42 provided in the second portion 13a2 that does not hold the stator 34 in the side wall 13a. The first rib 41 is formed to have higher strength than the second rib 42.

  At this time, the first portion 13a1 of the side wall 13a of the motor case 13 of the housing 10 is reinforced by the first rib 41 having higher strength than the second rib 42, and this reinforcement is performed by the second portion 13a2 of the side wall 13a. It has higher strength than the reinforcement received from the two ribs 42. Furthermore, the 1st rib 41 and the 2nd rib 42 improve the heat dissipation of the side wall 13a, and especially the heat dissipation of the 1st site | part 13a1 improves higher than the 2nd site | part 13a2. Therefore, the air inside the housing 10 is cooled via the side wall 13a and the ribs 41 and 42, whereby both the first bearing 23 and the second bearing 24 having different temperature rising tendencies are effectively cooled. . The electric supercharger 101 can achieve the cooling of the bearings 23 and 24 and the strength of the housing 10 that holds the stator 34 with different temperature rising tendency by a simple structure provided with the ribs 41 and 42.

  In the electric supercharger 101, the first rib 41 and the second rib 42 extend along the circumferential direction of the shaft 22 on the side wall 13 a of the motor case 13. Thereby, since the 1st rib 41 and the 2nd rib 42 can each extend so that the side wall 13a may be surrounded and the contact area with ambient air can be taken large, the cooling efficiency of the air in the housing 10 improves. .

  In the electric supercharger 101, the first rib 41 has a larger cross section than the second rib 42. Thereby, the structure in which the first rib 41 has higher strength than the second rib 42 is simplified.

  In addition, the electric supercharger 101 includes a first bearing 23 and a second bearing 24 that rotatably support the shaft 22 of the rotor 31 in the housing 10. The first bearing 23 includes the compressor wheel 21 and the second bearing. The first rib 41 is provided between the first bearing 23 and the stator 34 in the axial direction of the shaft 22, and the second rib 42 is provided from the stator 34 to the second bearing 24 in the axial direction of the shaft 22. Provided. As a result, in the side wall 13a, the region extending from the first bearing 23 to the stator 34 is subjected to a higher cooling action by the heat radiating rib 40 than the region extending from the stator 34 to the second bearing 24. Further, the first bearing 23 that is easily subjected to the heat of the supercharged air by the compressor wheel 21 and the stator 34 that generates heat from the coil 36 have a higher temperature rising tendency than the second bearing 24. Accordingly, the first bearing 23 and the stator 34 can be effectively cooled. Furthermore, by providing the second rib 42 in a region extending from the stator 34 to the second bearing 24, the axial length of the shaft 22 in this region is suppressed, and the electric supercharger 101 can be downsized.

  Further, in the electric supercharger 101, the housing 10 has a rib coupling portion 50 integrally formed with the first rib 41 so as to at least partially connect the adjacent first ribs 41 to each other. (51, 52) has fastening holes 51a, 52a through which a fastening member 54 for attaching the electric supercharger 101 is passed. As a result, the rigidity and strength of the first portion 13a1 where the first rib 41 on the side wall 13a is formed can be improved. Furthermore, the mounting leg of the electric supercharger 101 can be provided by a simple structure by the rib coupling portion 50.

  In the electric supercharger 101 of the embodiment, the first portion 13a1 where the first rib 41 is formed on the side wall 13a of the motor case 13 includes a portion where the side wall 13a and the stator core 35 are in contact with each other. Although it is a site | part between the edge part 35a and the seal plate 12, it is not limited to this, The site | part which the side wall 13a and the stator core 35 contact may be sufficient.

  Further, in the electric supercharger 101 of the embodiment, the first rib 41 and the second rib 42 of the heat radiating rib 40 are arranged so as to form a contour with a step in the radial direction. It is not limited. The first rib 41 and the second rib 42 may be configured to reduce the amount of protrusion from the side wall 13 a of the motor case 13 as it goes from the first bearing 23 to the second bearing 24. Alternatively, the first rib 41 and the second rib 42 may be configured to have a thickness that decreases from the first bearing 23 toward the second bearing 24. Alternatively, the first rib 41 and the second rib 42 may be a combination of the above two configurations. With the above-described configuration, the first rib 41 and the second rib 42 have a size and a heat radiation area corresponding to the temperature rising tendency of the first bearing 23, the stator 34, and the second bearing 24. Reduces usage and reduces weight.

In the electric supercharger 101 according to the embodiment, the heat dissipating rib 40 includes a plurality of annular plate-shaped first ribs 41 and second ribs 42, but is not limited thereto.
The first rib 41 and the second rib 42 may not be a continuous ring, but may be a ring divided by a cut surface in the radial direction. Furthermore, the division | segmentation position of the 1st rib 41 and the 2nd rib 42 may differ in the circumferential direction between adjacent ribs, or may be the same in the circumferential direction. Thereby, the turbulent flow of the air around the 1st rib 41 and the 2nd rib 42 generate | occur | produces, and the heat exchange efficiency with the 1st rib 41 and the 2nd rib 42 and air improves.
Further, the divided first rib 41 and second rib 42 may be shifted from each other in the axial direction of the shaft 22 without being arranged on the same circumference. Thereby, it becomes easier to generate turbulence in the air around the first rib 41 and the second rib 42.
Alternatively, the plurality of first ribs 41 may be continued in a spiral shape, and the plurality of second ribs 42 may be continued in a spiral shape. As a result, air turbulence is generated around the ribs.

  Further, in the electric supercharger 101 of the embodiment, the first rib 41 and the second rib 42 of the heat radiating rib 40 extend perpendicular to the axial direction of the shaft 22, but the axial direction It may be inclined with an angle. Furthermore, although the first rib 41 and the second rib 42 extend in parallel to each other, they need not be parallel. As a result, air turbulence is generated around the ribs.

In the electric supercharger 101 of the embodiment, the first rib 41 of the heat radiating rib 40 extends from the first bearing 23 to the end portion 35a of the stator core 35, but from the first bearing 23 to the stator core 35. It may be halfway through.
In the electric supercharger 101 of the embodiment, the two bearings 23 and 24 are provided. However, the present invention is not limited to this, and three or more bearings may be provided.
Further, the above-described cooling structure of the bearings 23 and 24 in the electric supercharger 101 of the embodiment does not cool the bearings by immersing the bearings in the lubricating oil or the flowing lubricating oil. If it is a feeder, it is applicable.

  DESCRIPTION OF SYMBOLS 10 Housing, 13 Motor case, 13a Side wall (wall part), 13a1 1st part, 13a2 2nd part, 21 Compressor wheel, 22 Shaft (rotary shaft), 23 1st bearing, 24 2nd bearing, 30 Electric motor (rotation) Electric machine), 31 rotor (rotor), 34 stator (stator), 40 heat radiating rib, 41 first rib, 42 second rib, 50 rib coupling portion, 51 first rib coupling portion, 51a, 52a fastening hole, 52 2nd rib coupling part, 54 fastening member, 101 electric supercharger.

Claims (5)

A rotating electrical machine having a rotatable rotor and a stator that is disposed and fixed so as to surround the rotor;
A compressor wheel coupled to the rotor to rotate integrally;
A housing for housing the rotor and the stator,
The housing is
A wall that surrounds and holds the stator;
A plurality of ribs projecting outward on the outside of the wall portion;
The plurality of ribs include a first rib provided at a first portion holding the stator in the wall portion, and a second rib provided at a second portion not holding the stator in the wall portion. Including
The electric supercharger is formed so that the first rib has higher strength than the second rib.   The electric supercharger according to claim 1, wherein the first rib has a larger cross section than the second rib. The housing includes a first bearing and a second bearing that rotatably support the rotating shaft of the rotor,
The first bearing is disposed between the compressor wheel and the second bearing;
The first rib is provided from the first bearing to the stator in the axial direction of the rotating shaft,
The electric supercharger according to claim 1 or 2, wherein the second rib is provided from the stator to the second bearing in an axial direction of the rotating shaft. The housing has a rib coupling portion integrally formed with the first rib so as to at least partially connect the adjacent first ribs;
The electric supercharger according to any one of claims 1 to 3, wherein the rib coupling portion has a fastening hole through which a fastening member for attaching the electric supercharger is passed.   The electric supercharger according to any one of claims 1 to 4, wherein the first rib and the second rib extend along a circumferential direction of the rotation shaft on the wall portion.

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