JP2015137548A - electric supercharger - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electric supercharger capable of improving the durability of a bearing.SOLUTION: An electric supercharger 101 comprises: an electric motor 30; a compressor wheel 21; a housing 10 that includes a wheel chamber 15 accommodating the compressor wheel 21, and a motor chamber 18 accommodating the electric motor 30; a first bearing 23 disposed in the motor chamber 18 and rotatably supporting a shaft 22 of the electric motor 30 driving the compressor wheel 21 to rotate; a bottom wall 13b of the housing 10 separating the wheel chamber 15 from the motor chamber 18 and penetrated by the shaft 22; and pressure regulation holes 13d and 13e formed to penetrate the bottom wall 13b and making the wheel chamber 15 communicable with the motor chamber 18.

Description

  The present invention relates to an electric supercharger.

As the supercharger, there is an electric supercharger that rotates a compressor wheel by a rotating electric machine such as an electric motor. In the electric supercharger, the bearing of the rotating shaft of the compressor wheel generates heat when the compressor wheel rotates at high speed and compresses the air, and thus the bearing needs to be cooled. Further, the bearing that rotatably supports the rotating shaft needs to reduce friction due to lubricating oil or the like.
For example, in the electric supercharger described in Patent Document 1, a motor rotor of a motor is fixed so as to rotate integrally with a rotation shaft to which a compressor wheel is attached, and a bearing as a bearing is attached to the motor rotor. On the other hand, it is provided on the compressor wheel side. Further, a bearing housing is provided between the compressor wheel and the motor so as to surround the bearing, and the bearing housing is configured so that oil can be circulated by supplying and discharging oil therein. The bearing is lubricated and cooled by oil flowing in the bearing housing.

JP 2012-102700 A

  In the electric supercharger disclosed in Patent Document 1, since the structure in which oil is allowed to flow in the bearing housing is adopted, the structure around the bearing is increased, and the electric supercharger itself is increased in size. In recent years, electric superchargers have been installed in automobiles, and space saving is required. For this reason, a compact rolling bearing (ball bearing) is used as the bearing on the compressor wheel side, and grease is enclosed in the bearing in advance during manufacture, thereby reducing the size of the electric supercharger. Yes.

  In the case of the electric supercharger as described above, the bearing of the rotating shaft that connects the compressor wheel and the electric motor is provided in the closed motor housing that houses the electric motor, and the compressor wheel housing space outside the motor housing. It arrange | positions in the vicinity of the wall part of an adjacent motor housing. For this reason, the pressure of the air supercharged in the housing space of the compressor wheel acts between the shaft and the wall of the motor housing, and the air pressure in the motor housing acts on the bearing. However, if the pressure of the supercharged air rises in the compressor wheel housing space that acts during supercharging, and the air pressure difference between the inside and outside of the motor housing increases, grease will escape from the inside of the bearing, reducing the durability of the bearing. There is a problem of doing.

  The present invention has been made to solve the above-described problems, and an object thereof is to provide an electric supercharger that improves the durability of a bearing.

  In order to solve the above-described problems, an electric supercharger according to the present invention includes a rotating electrical machine, a compressor wheel that is driven to rotate by the rotating electrical machine, a wheel chamber that houses the compressor wheel, and a rotating electrical machine room that houses the rotating electrical machine. And a housing that is disposed in the rotating electrical machine chamber and that rotatably supports the rotating shaft of the rotating electrical machine that rotationally drives the compressor wheel, and the housing in which the rotating shaft passes through the wheel chamber and the rotating electrical machine chamber. A partition and a partition through-hole formed through the partition and allowing the wheel chamber to communicate with the rotating electrical machine chamber are provided.

At least two partition wall through holes may be provided, and the partition wall through holes may be configured such that pressures in at least two of the partition wall through holes in the rotating electrical machine chamber are different during operation of the rotating electrical machine.
At least two of the partition wall through holes may have different distances from the rotation axis.
At least two of the partition wall through holes may have different sizes.
The rotating electrical machine rotates in the radial direction of the rotating shaft from the rotating shaft so as to generate a pressure difference in which the pressure on the radially outer side becomes higher than the pressure on the radially central side of the rotating shaft by rotating together with the rotating shaft. The partition wall through hole may be configured to generate a gas flow from one partition wall through hole to the other partition wall through the rotary electric machine chamber due to the pressure difference.
The bearing may be adjacent to a rotation shaft insertion hole through which the rotation shaft in the partition wall passes.

  According to the electric supercharger according to the present invention, the durability of the bearing can be improved.

It is a cross-sectional side view which shows the structure of the electric supercharger which concerns on Embodiment 1 of this invention. It is a cross-sectional side view which shows typically the flow of the air which cools the bearing in the electric supercharger of FIG. It is a section side view showing typically the composition of the pressure regulation hole in the electric supercharger concerning Embodiment 2 of this invention, and the flow of the air which cools a bearing.

Embodiments of the present invention will be described below with reference to the accompanying drawings.
Embodiment 1 FIG.
First, the configuration of the electric supercharger 101 according to Embodiment 1 of the present invention will be described.
Referring to FIG. 1, an electric supercharger 101 includes a supercharger 1 for supercharging sucked gas (in the present embodiment, air), and an electric motor 30 that is a rotary electric machine. And a drive unit 2 for driving using the.
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 metal compressor that houses the compressor wheel 21 by being assembled with each other. A cover 11 and a seal plate 12 are provided. 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 driving unit 2 includes a metal bottomed cylindrical motor case 13 and an end plate 14 that closes the opening of the motor case 13. The motor case 13 and the end plate 14 form a motor chamber 18 that houses the electric motor 30 therein. Here, the motor chamber 18 constitutes a rotating electrical machine chamber.
On the outer peripheral side of the cylindrical side wall 13a of the motor case 13, a plurality of heat radiating fins 13c are integrally formed so as to improve the cooling efficiency of the motor case 13 by ambient air.
The compressor cover 11, the seal plate 12, the motor case 13, and the end plate 14 form a housing 10 for the electric supercharger 101.

A seal plate 12 is fixed to the bottom wall 13 b that is the bottom of the motor case 13. A bottom wall through hole 13b1 that opens into the motor chamber 18 and opens toward the seal plate 12 is formed through the center of the bottom wall 13b. The bottom wall through-hole 13 b 1 has an inner diameter larger than the outer diameter of the shaft 22 and passes through the shaft 22. The bottom wall 13 b extends in the radial direction of the shaft 22. Here, the bottom wall 13 b constitutes a partition wall that separates the motor chamber 18 and the wheel chamber 15, and the bottom wall through hole 13 b 1 constitutes a rotation shaft insertion hole of the shaft 22.
Further, the seal plate 12 is formed with a plate through hole 12a that is adjacent to and communicates with the bottom wall through hole 13b1. The shaft 22 extends into the motor chamber 18 through the plate through hole 12a and the bottom wall through hole 13b1. At this time, the axial direction of the shaft 22 is a direction along the extending direction of the cylindrical side wall 13 a of the motor case 13.

  An outer peripheral surface 22 c 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 bottom wall 13b, and the second bearing 24 supports the shaft 22 near the end 22b on the end plate 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 bottom wall 13b, and is positioned adjacent to the bottom wall through hole 13b1. The inner diameter of the bottom wall through hole 13b1 is smaller than the outer diameter of the first bearing 23, and the first bearing 23 closes the gap between the bottom wall 13b and the shaft 22 in the bottom wall through hole 13b1.
The second bearing 24 has a cylindrical shape with a flange surrounding its outer periphery and is supported and fixed by a second bearing frame 26 fixed to the end plate 14.

A fixing nut 27 and a fixing ring 28 are mounted on the outer peripheral surface 22c of the shaft 22 that is passed through the insertion hole 21a at the center of the compressor wheel 21 on the one end 22a side.
The fixing ring 28 is located on the opposite side to the end 22a of the shaft 22 with respect to the compressor wheel 21 and in the plate through hole 12a. Furthermore, the fixing ring 28 is configured to engage with the shaft 22 and be prevented from moving to the opposite side of the compressor wheel 21.
The fixing nut 27 is positioned on the end 22a side with respect to the compressor wheel 21, and is screwed to the shaft 22 by a reverse screw method. By tightening with the fixing nut 27, the compressor wheel 21 is sandwiched between the fixing nut 27 and the fixing ring 28 and fixed in the axial direction.

A cylindrical rotor core 31 is provided on the outer peripheral surface 22 c 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 32 is embedded in the rotor core 31 along the outer peripheral surface thereof.
Further, in the motor chamber 18, a cylindrical stator core 33 is provided so as to surround the outer periphery of the rotor core 31. The stator core 33 is fixed to the side wall 13 a of the motor case 13. Furthermore, a winding is wound in the stator core 33, and this winding forms a coil 34 and protrudes from both ends of the stator core 33.
When electric power is supplied to the winding, a rotating magnetic field is generated from the coil 34, and the rotor magnet 31 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 32.

  The shaft 22, the rotor core 31, the permanent magnet 32, the stator core 33, and the coil 34 as described above constitute the electric motor 30. The shaft 22 also serves as the rotation shaft of the compressor wheel 21 and the electric motor 30.

Further, the bottom wall 13b of the motor case 13 is formed with a first pressure adjusting hole 13d and a second pressure adjusting hole 13e that open into the motor chamber 18 and open toward the seal plate 12. Here, the first pressure adjusting hole 13d and the second pressure adjusting hole 13e constitute a partition wall through hole.
The second pressure adjustment hole 13e is disposed at a position closer to the shaft 22 in the radial direction than the first pressure adjustment hole 13d. That is, the first pressure adjustment hole 13d is located at a distance L1 from the central axis CA of the shaft 22, that is, the radial distance L1, and the second pressure adjustment hole 13e is at a radial distance L2 (L2 <L1) from the central axis CA. positioned. Further, the first pressure adjusting hole 13d and the second pressure adjusting hole 13e are located on the radially outer side of the bottom wall through hole 13b1 and have the same inner diameter.

Next, the operation of the electric supercharger 101 according to Embodiment 1 of the present invention will be described.
Referring to FIG. 1, in the electric supercharger 101, when electric power is applied to the coil 34 of the electric motor 30 by a power source (not shown), the rotor core 31 is rotationally driven by the rotating magnetic field generated by the coil 34, whereby the shaft 22 and the compressor wheel 21 are driven to rotate at high speed about the central axis CA.

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 is compressed in the wheel chamber 15 to increase the pressure, and a part of the compressed air passes between the seal plate 12 and the fixing ring 28 and between the fixing ring 28 and the shaft 22. It flows into the bottom wall through hole 13b1. The compressed air that has flowed in tends to flow between the seal plate 12 and the bottom wall 13b of the motor case 13 toward the first pressure adjustment hole 13d or the second pressure adjustment hole 13e.

  1 and 2 together, in the motor chamber 18, the rotor core 31 protruding in the radial direction from the shaft 22 rotates at a high speed, so that air flows from the shaft 22 to the outside in the radial direction. It is biased to a position far from 22 in the radial direction. That is, the pressure of the air in the motor chamber 18 increases as the radial distance from the shaft 22 increases. Therefore, in the motor chamber 18, the pressure in the vicinity of the second pressure adjustment hole 13e is lower than the pressure in the vicinity of the first pressure adjustment hole 13d.

For this reason, the air between the seal plate 12 and the bottom wall 13b flows toward the second pressure adjustment hole 13e having a lower pressure and flows into the motor chamber 18 through the second pressure adjustment hole 13e.
In the motor chamber 18, the pressure in the vicinity of the second pressure adjusting hole 13e rises due to the air flowing in one after another, so that the air that has flowed in is directed toward the vicinity of the shaft 22 where the pressure is low, as indicated by the dashed arrow in FIG. And flows along the side wall 13a of the motor case 13 toward the vicinity of the first pressure adjusting hole 13d having a low pressure. The air that has flowed into the vicinity of the shaft 22 flows again outward in the radial direction by the action of the rotating rotor core 31, and flows toward the first pressure adjusting hole 13d having a low pressure. Thereafter, the air flows out of the motor chamber 18 through the first pressure adjusting hole 13d. The outflowed air does not flow to the bottom wall through hole 13b1 and the wheel chamber 15 where the pressure is high, but flows out between the seal plate 12 and the bottom wall 13b to the outside of the electric supercharger 101.

  In the course of flow from the second pressure adjustment hole 13e to the first pressure adjustment hole 13d, the air is cooled by heat radiation through the heat radiation fins 13c of the motor case 13, and the bearings 23 and 24 are mainly the first bearing 23. Cool directly. In particular, since the first bearing 23 receives heat transfer from the air that is heated by being compressed by the compressor wheel 21 through the shaft 22, the seal plate 12, and the bottom wall 13 b, the temperature is higher than that of the second bearing 24. . For this reason, cooling the first bearing 23 as a main component is effective for cooling the bearings 23 and 24 to the same state. The first bearing 23 is also directly cooled by the air flowing into the adjacent bottom wall through hole 13b1.

In addition, by flowing the compressed air in the bottom wall through hole 13b1 into the motor chamber 18, the pressure in the bottom wall through hole 13b1 is lowered and the pressure in the motor chamber 18 is raised, and the differential pressure between them is increased. Lower. That is, the differential pressure between the bottom wall through hole 13b1 side and the motor chamber 18 side in the first bearing 23 is reduced.
In the electric supercharger 101, since lubricating oil cannot be circulated in the motor chamber 18, grease is enclosed in the bearings 23 and 24 at the time of manufacture. As described above, since the differential pressure inside and outside the motor chamber 18 with the first bearing 23 interposed therebetween is reduced, the enclosed grease may be pushed out of the first bearing 23 by the compressed air in the bottom wall through hole 13b1. It is prevented.

  As described above, the electric supercharger 101 according to the first embodiment of the present invention includes the electric motor 30, the compressor wheel 21 that is rotationally driven by the electric motor 30, the wheel chamber 15 that houses the compressor wheel 21, and the electric motor. A housing 10 having a motor chamber 18 that accommodates 30; a first bearing 23 that is disposed in the motor chamber 18 and rotatably supports a shaft 22 of an electric motor 30 that rotationally drives the compressor wheel 21; And a bottom wall 13b of the housing 10 through which the shaft 22 passes, and a first pressure adjusting hole 13d and a first pressure adjusting hole 13d formed through the bottom wall 13b and capable of communicating the wheel chamber 15 with the motor chamber 18. And two pressure adjusting holes 13e. The first pressure adjustment hole 13d and the second pressure adjustment hole 13e are configured so that the pressures in the first pressure adjustment hole 13d and the second pressure adjustment hole 13e in the motor chamber 18 are different when the electric motor 30 is operated. Is done.

  During operation of the electric motor 30, a part of the air in the wheel chamber 15 compressed by the compressor wheel 21 flows toward the first pressure adjustment hole 13d and the second pressure adjustment hole 13e. In the motor chamber 18, since the pressure in the first pressure adjustment hole 13d and the second pressure adjustment hole 13e is different, after flowing from the wheel chamber 15 through the first pressure adjustment hole 13d or the second pressure adjustment hole 13e, A flow of air flowing between the first pressure adjustment hole 13d and the second pressure adjustment hole 13e and flowing out through the second pressure adjustment hole 13e or the first pressure adjustment hole 13d is formed. Thereby, the 1st bearing 23 is directly cooled by the air which flows one after another. And the said effect | action can be acquired by adjusting the structure of 13d of 1st pressure adjustment holes or the 2nd pressure adjustment hole 13e. Therefore, the electric supercharger 101 simplifies the structure for cooling the first bearing 23, thereby enabling cost reduction. Further, the first bearing 23 receives the pressure of air compressed in the wheel chamber 15 from the outside of the motor chamber 18 and receives the pressure of air in the motor chamber 18. By introducing a part of the air compressed by the compressor wheel 21 into the motor chamber 18, the differential pressure of air acting on the first bearing 23 inside and outside the motor chamber 18 is reduced. Leakage of encapsulated grease is suppressed.

In the electric supercharger 101, the first pressure adjustment hole 13d and the second pressure adjustment hole 13e have different distances from the shaft 22. At this time, when the electric motor 30 is in operation, the first pressure adjusting hole 13d and the second pressure adjusting hole 13e are configured so that the pressure varies in the motor chamber 18 according to the radial distance from the shaft 22. The pressure can be different.
In the electric supercharger 101, the first bearing 23 is adjacent to the bottom wall through hole 13b1 through which the shaft 22 in the bottom wall 13b passes. At this time, the first bearing 23 is also directly cooled by the air flowing from the wheel chamber 15 to the bottom wall through hole 13b1.

  Further, in the electric supercharger 101, the electric motor 30 rotates with the shaft 22, thereby generating a pressure difference in the motor chamber 18 where the pressure on the radially outer side is higher than the pressure on the radial center side of the shaft 22. As described above, the rotor core 31 is provided so as to protrude from the shaft 22 in the radial direction of the shaft 22, and the first pressure adjustment hole 13 d and the second pressure adjustment hole 13 e are adjusted in the motor chamber 18 by the pressure difference. An air flow from the hole 13e to the first pressure adjusting hole 13d is generated. At this time, the pressure difference in the motor chamber 18 caused by the rotation of the rotor core 31 and the configuration of the first pressure adjusting hole 13d and the second pressure adjusting hole 13e are interacted to directly connect the first bearing 23. A cooling air flow can be formed in the motor chamber 18.

Embodiment 2. FIG.
The electric supercharger according to the second embodiment of the present invention includes the first pressure adjusting hole 13d and the second pressure formed in the bottom wall 13b of the motor case 13 in the electric supercharger 101 according to the first embodiment. The adjustment hole 13e is disposed at a position equidistant from the shaft 22 in the radial direction, and the inner diameter of the second pressure adjustment hole 13e is larger than that of the first pressure adjustment hole 13d.
In the following embodiments, the same reference numerals as those in the previous drawings are the same or similar components, and thus detailed description thereof is omitted.

  Referring to FIG. 3, for the first pressure adjustment hole 213d and the second pressure adjustment hole 213e formed in the bottom wall 13b of the motor case 13, the first pressure adjustment hole 213d is a radial distance L1 from the central axis CA of the shaft 22. The second pressure adjustment hole 213e is located at a radial distance L2 (where L2 = L1) from the central axis CA. Furthermore, the second pressure adjustment hole 213e is formed with a larger diameter than the first pressure adjustment hole 213d.

For this reason, immediately after the start of the electric compressor, in the motor chamber 18, both the first pressure adjustment hole 213 d and the second pressure adjustment hole 213 e having the same radial distance from the shaft 22 pass through the bottom wall through hole 13 b 1. Compressed air flows in. However, since the first pressure adjustment hole 213d has a smaller diameter than the second pressure adjustment hole 213e, the pressure in the vicinity of the first pressure adjustment hole 213d is greater than the pressure in the vicinity of the second pressure adjustment hole 213e in the motor chamber 18. Will gradually become higher.
As a result, the compressed air in the bottom wall through hole 13b1 flows into the motor chamber 18 through the second pressure adjustment hole 213e as shown by the broken line arrow in FIG. It flows along the shaft 22 (see FIG. 1) or through the vicinity of the shaft 22 toward the first pressure adjusting hole 213d having a low pressure. Thereafter, the air flows out from the motor chamber 18 through the first pressure adjustment hole 213d.

Therefore, in the motor chamber 18, the air directly cools the bearings 23 and 24, mainly the first bearing 23, while being cooled by heat radiation through the heat radiation fins 13 c (see FIG. 1) of the motor case 13. . At the same time, the differential pressure between the bottom wall through hole 13b1 side and the motor chamber 18 side in the first bearing 23 becomes low.
Moreover, since the other structure and operation | movement of the electric supercharger which concern on Embodiment 2 of this invention are the same as that of Embodiment 1, description is abbreviate | omitted.

  And according to the electric supercharger in Embodiment 2, the same effect as the electric supercharger 101 of the said Embodiment 1 is acquired. That is, since the first pressure adjustment hole 213d and the second pressure adjustment hole 213e have different sizes, as described above, the first pressure adjustment hole 213d is provided in the motor chamber 18 during operation of the electric compressor. The pressure in the vicinity and the pressure in the vicinity of the second pressure adjustment hole 213e are different. Thereby, in the motor chamber 18, an air flow is generated between the first pressure adjusting hole 213d and the second pressure adjusting hole 213e, and the air is directly cooled by the air flowing through the bearings 23 and 24.

  In the electric supercharger according to the second embodiment, the first pressure adjustment hole 213d and the second pressure adjustment hole 213e are arranged at the same distance from the shaft 22 in the radial direction. The adjustment hole 213d may be arranged at a position farther in the radial direction from the shaft 22 than the second pressure adjustment hole 213e. As a result, the differential pressure between the vicinity of the first pressure adjustment hole 213d and the vicinity of the second pressure adjustment hole 213e can be increased, the air flow rate in the motor chamber 18 is increased, and the cooling effect by air is improved. Can be made.

  In the electric supercharger according to the first and second embodiments, the two first pressure adjustment holes and the second pressure adjustment hole are provided in the bottom wall 13b of the motor case 13, but only one pressure adjustment hole is provided. There may be. During the operation of the electric motor 30, part of the air in the wheel chamber 15 compressed by the compressor wheel 21 flows toward the pressure adjustment hole. At this time, a differential pressure is generated inside and outside the motor chamber 18 across the pressure adjustment hole. When the pressure of the external air is higher than the inside of the motor chamber 18, the air flows from the outside of the motor chamber 18 through the pressure adjustment hole, and the pressure of the air in the motor chamber 18 increases. . Moreover, the pressure of the air in the motor chamber 18 varies as the number of rotations of the rotor core 31 in the motor chamber 18 varies. If the pressure of the air inside the motor chamber 18 fluctuates and becomes higher than the outside after the inflow of air, the air flows out from the inside of the motor chamber 18 through the pressure adjusting hole. Accordingly, since the air flow and the air exchange occur in the motor chamber 18, the first bearing 23 and the second bearing 24 are cooled. The air inflow / outflow into the motor chamber 18 acts so as to reduce the differential pressure of the air inside and outside the motor chamber 18, so that the air acting on the first bearing 23 inside and outside the motor chamber 18 is reduced. The differential pressure is reduced, and leakage of the enclosed grease in the first bearing 23 is suppressed.

Moreover, in the electric supercharger of Embodiment 1 and 2, although the 1st pressure adjustment hole and the 2nd pressure adjustment hole were each provided in the bottom wall 13b of the motor case 13, 1st pressure adjustment hole and Two or more second pressure adjustment holes may be provided.
In the electric supercharger of the second embodiment, the first pressure adjustment hole 213d and the second pressure adjustment hole 213e of the bottom wall 13b of the motor case 13 are configured to be different from each other. It is not limited to this, The cross-sectional shape of the first pressure adjustment hole and the second pressure adjustment hole or the frictional resistance against the air on the inner wall surface may be made different from each other. That is, the ease of air passing through the first pressure adjustment hole and the second pressure adjustment hole may be different from each other.
Moreover, the cooling structure using the pressure adjustment hole of the bearing of the electric supercharger of Embodiments 1 and 2 does not cool the bearing by immersing it in the lubricating oil or the flowing lubricating oil, and uses gas. Any supercharger that cools can be applied.

  10 Housing, 13b Bottom wall (partition wall), 13b1 Bottom wall through hole (rotary shaft insertion hole), 13d, 213d First pressure adjustment hole (partition wall through hole), 13e, 213e Second pressure adjustment hole (partition wall through hole), DESCRIPTION OF SYMBOLS 15 Wheel chamber, 18 Motor chamber (rotating electrical machinery chamber), 21 Compressor wheel, 22 Shaft (rotating shaft), 23 1st bearing, 30 Electric motor (rotating electrical machinery), 31 Rotor core (rotor), 101 Electric supercharger.

Claims (6)

Rotating electrical machinery,
A compressor wheel driven to rotate by the rotating electrical machine;
A housing having a wheel chamber that houses the compressor wheel and a rotating electrical machine chamber that houses the rotating electrical machine;
A bearing disposed in the rotating electrical machine chamber and rotatably supporting a rotating shaft of the rotating electrical machine that rotationally drives the compressor wheel;
Separating the wheel chamber and the rotating electrical machine chamber, the partition wall of the housing through which the rotating shaft passes,
An electric supercharger comprising a partition wall through hole formed through the partition wall and allowing the wheel chamber to communicate with the rotating electrical machine chamber. At least two partition wall through holes are provided,
2. The electric supercharger according to claim 1, wherein the partition wall through hole is configured such that pressures in at least two of the partition wall through holes in the rotating electrical machine chamber are different during operation of the rotating electrical machine.   The electric supercharger according to claim 2, wherein the at least two of the partition wall through holes have different distances from the rotation shaft.   The electric supercharger according to claim 2 or 3, wherein the at least two of the partition wall through holes have different sizes. The rotating electrical machine rotates from the rotating shaft so as to generate a pressure difference in which the pressure on the radially outer side is higher than the pressure on the radially central side of the rotating shaft in the rotating electrical machine chamber by rotating together with the rotating shaft. A rotor provided to project in the radial direction of the rotating shaft;
The said partition through-hole is comprised so that the gas flow from one said partition through-hole to the other said partition through-hole may be produced in the said rotary electric machine chamber by the said pressure difference from the other said partition through-hole. The electric supercharger as described in.   The electric supercharger according to any one of claims 1 to 5, wherein the bearing is adjacent to a rotation shaft insertion hole through which the rotation shaft passes in the partition wall.

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