JP2000130177A - Turbo charger with generator and motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a turbo charger provided with a generator and motor which can stably support the bearing for pivoting the shaft rotated in the high speed by a turbine by a damper ring in a radial direction and thrust direction for a housing. SOLUTION: A shaft 4 driven in a high speed by the turbine of a turbo charger provided with a generator and motor is supported rotatably by an angular ball bearing 10 and damper ring 30. A lubrication oil is supplied through a second oil passage 39 branched from a first oil passage 36 from a diameter direction gap 51 in the axial direction gap 52 formed between the end surface 40 of the damper ring 30 and the end surface 48 of a side plate 49. The angular ball bearing 10 is supported stably in a thrust direction for a center housing 14 by the damping operation of an oil film formed in the axial direction gap 52.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a turbocharger provided with a generator / motor for supercharging intake air and converting exhaust gas energy into electric energy to recover energy.

[0002]

2. Description of the Related Art Generally, an engine equipped with a turbocharger includes a turbocharger having a turbine driven by exhaust gas energy, a shaft mounted with the turbine, and a compressor mounted on the shaft. In addition, an energy recovery device including a turbine driven by exhaust gas energy, a shaft mounted with the turbine, a compressor mounted on the shaft, and a generator / motor mounted on the shaft has been proposed for a turbocharger provided in the engine. ing. In addition, in the adiabatic engine equipped with a turbocharger, a turbocharger with a generator / motor in the exhaust system is arranged,
An arrangement in which an energy recovery device provided with a power generation turbine downstream of the turbocharger is proposed.

FIG. 3 is a sectional view showing a conventional ordinary turbocharger. The turbocharger performs supercharging with a turbocharger driven by exhaust gas of the engine for the purpose of improving the output during high-speed rotation of the engine or high-load operation. In the turbocharger 60 shown in FIG. 3, the body of the turbocharger 60 includes a turbine housing 12 that houses the turbine 2, a compressor housing 13 that houses the compressor 3, and both housings 12 between the turbine housing 12 and the compressor housing 13. 13 are connected to each other. The shaft 4 penetrating the body is provided with a bearing 62,
62 rotatably supported. A turbine blade 7 is attached to the shaft 4 at an end on the turbine 2 side, and a compressor blade 9 is attached to an end on the compressor 3 side.

The exhaust gas sent to the turbine scroll 6 through the exhaust pipe of the engine is supplied to the turbine 2 of the turbocharger 60 to rotate the turbine blade 7.
The rotation of the turbine blade 7 is transmitted to the compressor 3 via the shaft 4, and the compressor 3 rotates the compressor blade 9 to supercharge, that is, compresses air and supplies the air to the engine.

Since the shaft 4 rotates at a high speed of 100,000 to 200,000 rpm, a shaft supporting structure is devised for stable rotation. FIG. 4 is an enlarged sectional view showing a part of the bearing structure of the turbocharger 60 shown in FIG. The shaft 4 in the center housing 61
Are an angular type ball bearing composed of an inner ring 63 and an outer ring 64 fixed to the shaft 4 and a ball 65 interposed between the inner ring 63 and the outer ring 64. The ball 65 is held by the retainer 66 to the inner ring 6.
3 and the outer ring 64 so as not to fall off.

The outer rings 64 of the bearings 62 are mounted by press-fitting into both ends of a through hole 69 of an oil film damper 68 fitted into a through hole 67 of the center housing 61. The oil film damper 68 is an integral type that is not divided on the turbine side and the compressor side. The bearings 62, 62 are provided with a coil spring 70 between the outer rings 64, 64 via a spring receiver 71, and are urged away from each other by a predetermined force of the coil spring 70.

To enable the shaft 4 to rotate at a high speed, lubricating oil is supplied to the bearings 62, 62 and the oil film damper 68. The lubricating oil is supplied to the center housing 61
Is supplied to the gap 73 between the oil film damper 68 and the through hole 67 of the center housing 61 through an oil supply passage 72 formed in
After lubricating and cooling 2,62, the oil film damper 6
The oil is discharged through an oil drain 74 formed continuously with the center housing 8 and the center housing 61. Oil film damper 68
Are floatingly supported by the center housing 61 via an oil film formed by the lubricating oil supplied to the gap 73. The high-speed rotation of the shaft 4 is enabled by the vibration damping action of the oil film.

Since the bearings 62, 62 are angular type ball bearings, the thrust force acting on the turbine 2 and the compressor 3 is transmitted from the center housing 61 to the turbine housing 12 and the compressor housing via the bearings 62, 62 and the oil film damper 68. 13 is transmitted. An example of a bearing support structure using such an oil film damper is disclosed in Japanese Utility Model Laid-Open No. 61-134536. In the bearing structure disclosed in this publication, when a thrust force greater than the urging force of the spring is generated in the shaft, a step for a bearing stopper is formed on the inner peripheral surface of the oil film damper so that the two bearings do not approach each other. ing.

A turbocharger generator recovers exhaust gas energy as electric energy by driving a turbine by exhaust gas energy of a vehicle engine and generating electric power by a generator connected to the turbine. FIG. 5 is a cross-sectional view showing a conventional turbocharger provided with a generator / motor. The turbocharger 80 provided with the generator / motor shown in FIG. 5 has the shaft 4 extended from the turbocharger 60 shown in FIGS. 3 and 4, and a generator 82 is incorporated between the center housing 61 and the compressor housing 13. Equivalent to something. The same components as those of the turbocharger 60 shown in FIG. 3 are denoted by the same reference numerals, and redundant detailed description will be omitted.

[0010] Turbocharger 8 equipped with a generator / motor
The zero generator 82 is housed in a generator housing 81 attached at both ends to the center housing 61 and the compressor housing 13 between the turbine 2 and the compressor 3. The generator 82 includes a rotor 83 composed of a permanent magnet attached to the shaft 4 driven by exhaust energy and rotating with the shaft 4.
And a stator 84 composed of a coil attached to the generator housing 81 around the rotor 83.
The generator 82 converts a part of the output of the turbine 2 driven by the exhaust gas into electric energy, and drives a motor directly connected to the engine with the electric power, thereby realizing the exhaust gas energy recovery. The shaft 4 is
With respect to the center housing 61, the float bearings 85, 8
The rotor 83 is rotatably supported by the shaft 5 and protrudes from the float bearing 85 on the compressor side.
Is attached.

An example of a turbocharger for driving a generator with a driving force obtained by a turbine is disclosed in Japanese Patent Laid-Open No. 2-1181.
There is one disclosed in Japanese Patent Publication No. 5 (JP-A-5). Since the turbine efficiency changes over a wide range when the amount of exhaust gas changes, this turbocharger supplies the exhaust gas to a large or small turbine arranged coaxially according to the rotation speed of the rotating shaft. It is intended to maintain high efficiency.

Another example of a turbocharger having a generator / motor is disclosed in Japanese Patent Application Laid-Open No. 2-298627. The turbocharger provided with this generator / motor has a type in which a generator section is disposed at a portion of a shaft supported by a center housing, which protrudes from a side opposite to a turbine housing.

Further, as another example of a turbocharger provided with a generator / motor, a hollow shaft outer shaft rotatable on the same central axis and independently of the shaft is provided on the outer periphery of the shaft, and the outer shaft is provided with a power generator. There is a turbine provided with a mechanical turbine and a generator rotor (JP-A-6-288).
242). In this example, the turbine for driving the compressor and the turbine for the generator are arranged in series along the exhaust gas flow. The outer shaft for the casing and the shaft for the outer shaft are rotatably supported by bearings. The shaft is rotatably supported in the thrust direction with respect to the center housing via a thrust bearing attached to the shaft by a nut. Furthermore,
The outer shaft is rotatably supported in the thrust direction by a center housing via a thrust bearing.

[0014]

When a turbocharger provided with such a generator / motor is used in a large engine, the rotor 83 has a pair of float bearings in a bearing structure as shown in FIG. Compressor 3 than 85
Toward the side, the amount of overhang extending from the float bearing 85 to the compressor 3 side increases, and the axial length of the generator housing 81 increases. In addition, the rotor 83
It is made of magnetic material and has a large weight. Therefore, when the shaft 4 rotates, the rotor 83 provided at a portion extending from the float bearing 85 to the compressor 3 side easily whirls together with the compressor 3, so that high-speed rotation becomes impossible.

Therefore, the shaft on which the rotor is mounted is supported by the housing on both sides of the rotor in the axial direction, so that the shaft and the rotor can be stably rotated at a high speed, and the shaft is generated. There is a problem to be solved in that it is possible to maintain the radial force and the thrust force.

[0016]

SUMMARY OF THE INVENTION An object of the present invention is to provide a turbocharger having a generator / motor for recovering energy from exhaust gas from an engine by converting the energy into electric energy. An object of the present invention is to provide a turbocharger having a generator / motor capable of supporting not only a radial force generated on a shaft but also a thrust force by a ring.

The present invention provides a turbine disposed in a housing and driven by exhaust gas energy, a compressor disposed in the housing, a shaft connecting the turbine and the compressor, and mounted on the shaft. A generator having a generator / motor rotor and a stator attached to the housing; and bearings disposed at both axial positions of the rotor to rotatably support the shaft. The bearings are provided on the housing via damper rings which are individually provided for the bearings and which form a damping oil film in a radial gap formed between the housing and the bearing. And the damper ring is
The movement in the axial direction is regulated by a regulating member provided in the housing, and is urged in a direction away from the regulating member by a spring means provided between the housing and the damper ring. A first oil passage for guiding the lubricating oil from the radial gap to the opening facing the bearing for supplying the lubricating oil to the bearing; a ring end surface of the damper ring and a regulating end surface of the regulating member opposed to the ring end surface; And a second oil passage that guides lubricating oil to an axial gap formed between the two.

The turbocharger provided with the generator / motor according to the present invention is configured as described above, and operates as follows. That is, in the turbocharger provided with the generator / motor, the shaft connecting the turbine and the compressor is rotatably supported by the housing by bearings respectively disposed at both axial positions of the rotor mounted on the shaft. Have been. That is, the heavy rotor is arranged between the bearings. Further, each bearing is individually provided in the housing corresponding to each bearing, and is supported via a damper ring forming a vibration damping oil film in a radial gap formed between the housing and the bearing. . That is, the shaft is stably supported in the radial direction by the damping oil film formed in the radial gap formed between the damper ring and the housing. Further, the damper ring is restricted in its axial movement by a regulating member provided on the housing, and is urged in a direction away from the regulating member by a spring means disposed between the damper ring and the housing. Lubricating oil is guided through the second oil passage into an axial gap formed between the ring end face and the regulating end face of the regulating member facing the ring end face. Accordingly, lubricating oil is supplied to the axial gap formed in the opening direction by the spring means, and the supplied lubricating oil causes the damper ring and the housing to be in the same manner as the damping oil film formed in the radial gap. An oil film for vibration damping is formed in between. as a result,
When the shaft is to be displaced in the axial direction, the gap in the axial direction is narrowed with respect to one of the bearings, and the shaft is stably supported by the housing in the thrust direction, so that high-speed rotation is possible.

Further, in the turbocharger provided with the generator / motor, the second oil passage branches from the first oil passage in a direction parallel to the axial direction of the shaft and opens to the end face of the ring. The first oil passage is formed by drilling in the radial direction of the damper ring like drilling. The second oil passage is formed by drilling from the ring end surface to a position intersecting with the first oil passage in a direction different from the axial direction of the shaft, thereby forming an oil passage in the damper ring. It will be easier.

In the turbocharger provided with the generator / motor, the bearing is disposed between the inner ring pressed into the shaft, the outer ring pressed into the damper ring, and the inner ring and the outer ring. Has a ball. When the bearing is pressed into the damper ring until the end face of the outer ring of the bearing opposite to the stator abuts against the bottom surface of the press-fit hole of the damper ring, the thrust force from the shaft is reduced.
Properly transmitted to the damper ring via the bearing.

In the turbocharger provided with the generator / motor, the bearing is an angular ball bearing. The angular ball bearing transmits not only the radial force acting on the shaft but also the thrust force to the damper ring via the ball. Since the damper ring is supported in the radial direction and the thrust direction with respect to the housing with vibration damping action, the shaft is eventually moved in the radial direction and the thrust direction with respect to the housing through the angular ball bearing and the damper ring in series. Supported.

In the turbocharger provided with the generator / motor, the rotor is a permanent magnet, and the stator is a stator coil. The rotor made of permanent magnets is heavy, but is supported by bearings on both sides of the shaft and supported by a damper ring that forms an oil film that has a vibration damping effect not only in the radial direction but also in the thrust direction. Therefore, the shaft can rotate at high speed.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a turbocharger having a generator / motor according to the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view showing an embodiment of a turbocharger provided with a generator / motor according to the present invention.
FIG. 2 is an enlarged cross-sectional view showing one of the bearing structures that rotatably support the shaft of the turbocharger including the generator / motor shown in FIG.

A turbocharger 1 equipped with a generator / motor shown in FIG. 1 (hereinafter abbreviated as “turbocharger 1” in the description of the embodiment) is a turbine 2 driven by exhaust gas energy of an engine. It has a shaft 4 attached thereto and a compressor 3 attached to the shaft 4. Further, the housing of the turbocharger 1 includes a turbine housing 12, a compressor housing 13, and a center housing. The center housing includes a turbine-side center housing 14 and a compressor-side center housing 15. The turbine housing 12 is fixed to a turbine side center housing 14, and the generator 5 is disposed in the center housing 14. Turbine side center housing 14
A compressor-side center housing 15 is fixed to the other end of the compressor, and a compressor housing 13 is fixed to the compressor-side center housing 15.

The shaft 4, which is a solid shaft, is provided with angular contact ball bearings 10, 11 with respect to the turbine side center housing 14 and the compressor side center housing 15, respectively.
It is rotatably supported by. On the shaft 4,
The rotor 16 of the generator 5 composed of a permanent magnet is attached, and the angular ball bearings 10 and 11 have the rotor 1 between them.
6 so that they can be arranged. A stator 17 composed of a stator coil is arranged in the turbine side center housing 14 corresponding to the outer periphery of the rotor 16. The stator 17 is wound with a coil, and generates an electromotive force in accordance with a change in magnetic flux of the permanent magnet as the rotor 16 as the shaft 4 rotates. A sleeve 18 made of carbon fiber reinforced plastic as a reinforcing member fitted around the rotor 16 prevents the permanent magnet from bursting due to a large centrifugal force generated in the rotor 16 due to high-speed rotation. Rotor 1
6 and the stator 17 constitute a generator.
In the turbocharger 1, the turbine housing 12
The exhaust gas flow is introduced through the exhaust turbine scroll 6 and rotates the turbine blade 7 fixed to one end of the shaft 4.

The details of the support of the shaft 4 by the angular ball bearings 10 and 11 will be described with reference to FIG. The angular contact ball bearing 10 is provided with the inner ring 2 press-fitted into the shaft 4.
0, the outer ring 21 and the inner ring 20 pressed into the damper ring 30
The ball 22 includes a ball 22 as a rolling element rotatably incorporated between the ball and the outer ring 21, and a retainer 23 for preventing the ball 22 from falling off the bearing 10. In this embodiment, a counter bore 24 is formed only in the inner ring 20.

A side plate 49 is fitted into the turbine side center housing 14 in a hole defined by the inner peripheral surface 46 and the end surface 47. A seal ring 5 is provided between the side plate 49 and the shaft 4.
3 is provided, and has a sealing function for preventing leakage of lubricating oil described later to the turbine 2 side. The damper ring 30 is fitted and mounted in the inner peripheral surface 44 of the turbine side center housing 14 until it contacts the side plate 49. The damper ring 30 has a cylindrical inner surface 31 and an annular step surface 32 connected to the cylindrical inner surface 31 on the side facing the stator 17 side. Bearing 1
The 0 outer ring 21 is pressed into the damper ring 30 until it comes into contact with the cylindrical inner surface 31 and the step surface 32. The damper ring 30 is also provided on the angular ball bearing 11 side, but has the same structure, and therefore, detailed description is omitted.

An annular groove 33 is formed on the outer peripheral surface 34 of the damper ring 30, and an O-ring 50 is provided in the annular groove 33. The O-ring 50 contacts the inner peripheral surface 44 of the turbine-side center housing 14 and
0 and an inner peripheral surface 44 of the turbine-side center housing 14.

A shallow oil inlet 35 is formed in the outer peripheral surface 34 of the damper ring 30 at a position separated from the annular groove 33, and the damper ring 30 is bored from the oil inlet 35 in the radial direction to have a relatively large diameter. Oil passage 36a is formed. A relatively small-diameter oblique oil passage 36b extending diagonally from the bottom of the oil passage 36a toward the bearing 10.
Are formed. The oil passage 36a and the oblique oil passage 36b constitute a first oil passage 36 in the turbocharger 1 according to the present invention. Lubricating oil from an oil supply passage 45 formed in the turbine side center housing 14 is supplied to a narrow radial gap 51 formed between the outer peripheral surface 34 of the damper ring 30 and the inner peripheral surface 44 of the turbine side center housing 14. Supplied to Since the radial gap 51 is sealed by the O-ring 50 provided on the stator 17 side, the lubricating oil in the radial gap 51 does not leak directly to the stator 17 side.

The lubricating oil from the oil supply passage 45
Through the first oil passage 36, the oil is ejected from the ejection port 38, which is the opening of the oblique oil passage 36b, toward the angular ball bearing 10 to lubricate the angular ball bearing 10. Turbine 2
Since the shaft 4 is driven by the flow of the exhaust gas, the temperature of the shaft 4 becomes high, and the permanent magnet as the rotor 16 mounted on the shaft 4 also becomes high in temperature and may be demagnetized. The lubricating oil jetted toward the angular ball bearing 10 also serves to cool the shaft 4. The lubricating oil that is jetted toward the angular ball bearing 10 also transmits heat to the seal ring 53 of the side plate 49 to release the heat of the shaft 4 to the center housing 14. In order to improve the cooling performance, cooling water is introduced into a cooling passage 55 formed in the center housing 14 near the turbine 2.

From the middle of the oil passage 36, a second oil passage 39 extending in the axial direction and reaching an opening 41 formed in the end face 40 of the damper ring 30 on the side of the side plate 49 is branched. The second oil passage does not necessarily need to be formed by branching off from the first oil passage, but may be formed directly from the radial gap 51. End face 40 of damper ring 30
An oil film for holding the end face is formed in the axial gap 52 formed between the end face 48 and the end face 48 of the side plate 49. The side plate 49 has an end face 48
It functions as a regulating member that regulates the movement of the damper ring 30 to the side opposite to the stator 17.

On the side plate 49 side of the damper ring 30, a cylindrical inner surface 42 and a step portion 43 following the inner surface 42 are formed, and the end surface 48 of the side plate 49 and the damper ring 3 are formed.
0 between the damper ring 30 and the stator 1.
A coil spring 54 biasing toward the side 7 is provided. Accordingly, the two angular ball bearings 10 and 11 are urged inwardly from both sides by the coil springs 54 and 54, and if no thrust force acts on the shaft 4, the two bearings 10 and 11 will Ball 22,
It is urged to a neutral position determined by the position of the counter bore 24 of the inner ring 20, 20.

The stator 17 generates heat due to a change in magnetic flux crossing the stator 17 and a current flowing through the coil of the stator 17, and as a result, the power generation performance of the stator 17 is reduced and sufficient power can be taken out. Can not. Therefore, stator 1
The cooling passage 57 is extended from the cooling passage 55 provided near the turbine 2 through the communication passage 56 to the center housing 14 in which the cooling passage 57 is mounted radially outward of the stator 17. The stator 17 is cooled by flowing cooling water.

Since the turbocharger 1 is configured as described above, it can operate as follows. In the turbocharger 1, exhaust gas from an engine (not shown) is introduced from the turbine scroll 6 into the turbine housing 12, so that the exhaust gas acts on the turbine blades 7 to drive the turbine 2. Turbine 2
Drives the compressor 3 through the shaft 4 and rotates the compressor blade 9 of the compressor 3 so that the intake air is supercharged to the engine. The permanent magnet as the rotor 16 attached to the shaft 4 rotates, and the power generator 5 generates power. The generator 5 generates an amount corresponding to consumption or power storage according to the operation state of the engine, but when the power is not used, the rotor 16 only idles.

The damper ring 30 includes the angular ball bearing 1
The 0 side and the angular ball bearing 11 side are separately prepared and attached to the center housing 14. The lubricating oil film (oil film) formed between the outer peripheral surface 34 of the damper ring 30 and the inner peripheral surface 44 of the center housing 14 acts as a film damper, and acts on the shaft 4 during high-speed rotation of the shaft 4. If the thrust force exceeds the balancing force of the coil spring 54 and the damper ring 30 collides with the turbine-side center housing 14 or the side plate 49 attached to the turbine-side center housing 14, the axial gap 52
The thrust force can be stably countered by the buffering / damping action of the oil film satisfying the above. Therefore, the shaft 4 is stably supported by the turbine side center housing 14 even when rotating at high speed. In the above embodiment, the AC machine including the rotor 16 and the stator 17 has been described as a generator. However, an electric current is supplied to the stator 17 to use the AC machine as a motor, and the exhaust gas of the engine is sufficiently used. If this is not possible, the supercharging by driving the compressor may be performed by an electric motor.

[0036]

The turbocharger generator according to the present invention is configured as described above and has the following effects. That is, the turbocharger provided with the generator / motor according to the present invention is configured as described above.
It works as follows. That is, in the turbocharger provided with the generator / motor, the heavy rotor is disposed between the bearings, and the shaft is formed in a radial gap formed between the damper ring and the housing. It is stably supported in the radial direction by the vibrating oil film. Further, lubricating oil is supplied to the axial gap formed in the opening direction by the spring means, and the supplied lubricating oil allows the damper ring and the housing to be in the same manner as the damping oil film formed in the radial gap. An oil film for vibration damping is formed in between. As a result, even if the rotor is as heavy as a permanent magnet, the shaft is stably supported in the thrust direction with respect to the housing, enabling high-speed rotation without whirling. In addition, the generator can be driven stably, and the exhaust gas energy can be effectively recovered as electric energy.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing an embodiment of a turbocharger provided with a generator / motor according to the present invention.

FIG. 2 is an enlarged cross-sectional view showing a bearing structure of a turbocharger including the generator / motor shown in FIG.

FIG. 3 is a sectional view showing a conventional turbocharger.

FIG. 4 is an enlarged sectional view showing a part of the bearing structure of the turbocharger shown in FIG. 3;

FIG. 5 is a sectional view showing another conventional turbocharger.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Turbocharger provided with generator / motor 2 Turbine 3 Compressor 4 Shaft 5 Generator 7 Turbine blade 10, 11 Angular contact ball bearing 12 Turbine housing 13 Compressor housing 14 Turbine side center housing 15 Compressor side center housing 16 Rotor 17 Stator 20 Inner ring 21 Outer ring 30 Damper ring 34 Outer peripheral surface 36 First oil passage 39 Second oil passage 44 Inner peripheral surface 45 Oil supply passage 48 End surface 49 Side plate 51 Radial gap 52 Axial gap 54 Coil spring

Claims (5)

[Claims] 1. A turbine disposed in a housing and driven by exhaust gas energy, a compressor disposed in the housing, a shaft connecting the turbine and the compressor, and a power generator mounted on the shaft. A generator having an electric rotor and a stator attached to the housing; and bearings respectively disposed at axially opposite positions of the rotor to rotatably support the shaft, Each bearing is
The damper is provided individually with respect to the bearings for the bearings, and is supported via a damper ring forming a damping oil film in a radial gap formed between the housing and the damper. The ring is restricted from moving in the axial direction by a restricting member provided on the housing, and is urged in a direction away from the restricting member by spring means provided between the ring and the damper ring. A first oil passage for guiding the lubricating oil from the radial gap to an opening facing the bearing for supplying the lubricating oil to the bearing; and a ring end face of the damper ring and the regulating member opposed to the ring end face. A turbocharger comprising a power generator and an electric motor, wherein a second oil passage for guiding lubricating oil is formed in an axial gap formed between the regulating end face and the second gap. 2. The generator / motor according to claim 1, wherein the second oil passage branches off from the first oil passage in a direction parallel to an axial direction of the shaft and opens to an end surface of the ring. Turbocharger with. 3. The bearing according to claim 1, wherein the bearing comprises an inner ring press-fitted into the shaft, an outer ring press-fitted into the damper ring, and a ball disposed between the inner ring and the outer ring. Or a turbocharger provided with the generator / motor according to 2. 4. The turbocharger according to claim 1, wherein the bearing is an angular ball bearing. 5. The turbocharger according to claim 1, wherein the rotor is a permanent magnet, and the stator is a stator coil.