KR101969789B1 - Electric turbocharger with oilless bearing - Google Patents

Abstract

The present invention relates to an electric turbocharger provided with an oilless bearing and, more specifically, to an electric turbocharger provided with an oilless bearing, not leaking a lubricant, covered within the bearing, to an electric motor side even though there is a pressure difference between the compressor and electric motor during operation of the turbocharger. To this end, an aspect of the present invention provides the electric turbocharger provided with an oilless bearing, comprising: a stator installed within a motor housing; a rotor rotating relatively with respect to the stator if power is supplied; the electric motor, provided with a shaft, outputting rotational force of the rotor; the compressor provided with a compressor wheel arranged within a compressor housing in a state of being fixed on the shaft to press air supplied to a vehicle engine; and an insert arranged between the motor housing and the compressor housing, wherein the insert is provided with the bearing which restricts radial and axial movement of the shaft.

Description

[0001] Electric turbocharger with oilless bearing [0002]

The present invention relates to a motor-driven supercharger equipped with an oil-less bearing, and more particularly, to a motor-driven supercharger having a lubricant applied to the inside of a bearing, even if a pressure difference occurs between a compressor and an electric motor at the time of operation of the turbocharger, Which is capable of disassembling, replacing and reassembling a bearing fixed in a turbocharger according to the present invention.

Generally, a power generation device such as an engine that generates a driving force includes various devices for improving power efficiency. For example, a turbocharger rotates a turbine using energy possessed by the exhaust gas, As a device for pressurizing air through a connected compressor, the compressed air supplied to the combustion chamber of the engine is supplied to improve the filling efficiency of the engine, thereby increasing the engine output by about 20 to 30%.

However, in such a conventional turbocharger, since the turbine and the compressor are connected to each other by the same rotation axis, there is a problem that it is difficult to constantly pressurize the air because the torque varies greatly depending on the amount of exhaust gas.

In order to solve this problem, research and development of electric turbocharger that pressurizes the air and supplies it to the engine by rotating the rotary shaft connected to the compressor using an electric motor instead of the turbine has been carried out.

In such an electric turbocharger, there is provided a ball bearing for supporting a rotary shaft so that the rotary shaft connected to the compressor wheel is not moved in the axial direction and the radial direction. In the case of an oil-free type turbocharger in which no lubricant is separately supplied from the electric turbocharger, A lubricant is previously applied to the inside in order to secure it.

However, in such a turbocharger, there has been a problem that the lubricant inside the ball bearing leaks to the electric motor side due to the pressure difference between the compressor and the electric motor, and thus the ball bearing and the rotary component in the turbocharger are damaged .

In addition, although the inner ring of the ball bearing is press-fitted into the rotary shaft so that the ball bearing effectively supports the rotary shaft, and the outer ring is press-fitted into the housing of the turbocharger, when the ball bearing is fixed by press- There is a problem that it is impossible to disassemble, replace, and reassemble it at the time of breakage.

Therefore, it is necessary to improve these problems.

The present invention provides a motor-driven supercharger having an oil-less bearing that does not leak lubricant applied to the inside of a bearing to an electric motor even if a pressure difference occurs between a compressor and an electric motor during operation of the turbocharger .

Further, the present invention provides a motor-driven supercharger equipped with an oil-free bearing capable of disassembling, replacing and reassembling the bearing as needed after fixing the bearing in the turbocharger.

According to an aspect of the present invention, there is provided a motor-driven supercharger having an oil-less bearing, the motor-driven supercharger including a stator mounted in a motor housing, a rotor rotating relative to the stator when power is supplied thereto, A compressor having a compressor wheel disposed inside the compressor housing while being fixedly mounted on the shaft so as to pressurize the air supplied to the vehicle engine; And an insert disposed between the compressor housings, wherein the insert is provided with a bearing that limits radial and axial movement of the shaft.

At this time, the insert may be equipped with a support frame for supporting the bearing to prevent the bearing from being separated from the bearing insertion surface formed in the insert.

The support frame may be formed with an outer ring pressing surface for pressing the outer ring of the bearing in the axial direction.

The support frame may be formed with a leakage preventing surface extending radially inward from the pressing surface of the outer ring, and disposed adjacent to an outer circumferential surface of the shaft.

At this time, the leakage preventing surface may be disposed apart from the inner ring of the bearing.

In addition, a level difference may be formed in the leakage preventing surface in a direction in which the oil leakage preventing surface is separated from the inner ring of the bearing.

Alternatively, the leakage preventing surface may be inclined in a direction in which the leakage preventing surface is separated from the inner ring of the bearing.

The shaft may be formed with an inner ring insertion face into which the inner ring of the bearing is inserted and an inner ring pressing face extending radially outward from the inner ring insertion face to press the inner ring of the bearing in the axial direction.

At this time, a lock nut is provided to provide a fastening force to fix the compressor wheel to the shaft, and the fastening direction of the lock nut and the pressing direction of the pressing surface of the inner ring may be opposite to each other.

The motor-driven supercharger equipped with the non-lube bearing of the present invention having the above-described structure is provided with an insert between the electric motor and the compressor, a bearing is provided on the insert, and a separate support frame for fixing the bearing is fastened to the insert. It is possible to effectively support the shaft such that the shaft does not move in the axial direction and the radial direction even when the shaft rotates at a high speed according to the operation of the motor.

In addition, it is possible to prevent leakage of the internal lubricant in the insert frame, thereby preventing breakage of the internal parts of the bearing and the turbocharger in the electric supercharger.

In addition, it is possible to disassemble the support frame from the insert to separate the bearings, thereby making it possible to disassemble, replace and reassemble them as needed.

1 is a cross-sectional view illustrating a motor-driven supercharger according to an embodiment of the present invention.
2 is a sectional view showing a state in which a part of the structure of a motor-driven supercharger according to an embodiment of the present invention is disassembled.
3 is an enlarged cross-sectional view of a portion A in Fig.
4 is a cross-sectional view illustrating a support frame according to another embodiment of the present invention.
FIG. 5 is a cross-sectional view illustrating a state in which some components of a motor-driven supercharger according to an embodiment of the present invention are coupled.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings, which will be readily apparent to those skilled in the art to which the present invention pertains. The present invention may be embodied in many different forms and is not limited to the embodiments described herein. In order to clearly illustrate the present invention, parts not related to the description are omitted, and the same or similar components are denoted by the same reference numerals throughout the specification.

In this specification, the terms "comprises" or "having" and the like refer to the presence of stated features, integers, steps, operations, elements, components, or combinations thereof, But do not preclude the presence or addition of one or more other features, integers, steps, operations, components, parts, or combinations thereof.

1 is a cross-sectional view illustrating a motor-driven supercharger according to an embodiment of the present invention. FIG. 2 is a cross-sectional view illustrating a state in which a part of the motor-driven supercharger according to the embodiment of the present invention is disassembled, FIG. 4 is a cross-sectional view illustrating a support frame according to another embodiment of the present invention, and FIG. 5 is a cross-sectional view illustrating a state in which a part of the structure of the electric supercharger according to the embodiment of the present invention is coupled Fig.

1, the electric supercharger according to one embodiment of the present invention includes an electric motor 100 and a compressor 200 that pressurizes air supplied to the vehicle engine.

The electric motor 100 rotates the compressor wheel 210 provided in the compressor 200 when the electric power is supplied to the electric motor 100. The electric motor 100 includes a stator 110 mounted inside the motor housing 10, A rotor 120 that rotates relative to the stator 110 and a shaft 130 that outputs the rotational force of the rotor 120.

That is, when electric power is supplied to the electric motor 100 and the rotor 120 is rotated, the fixed shaft 130 rotates together with the rotor 120. The shaft 130 is provided with a compressor wheel 210 are fixedly mounted and rotate together with the shaft 130 to pressurize the air supplied to the compressor 200 and supply the compressed air to the engine combustion chamber.

At this time, the stator 110 is fixedly mounted inside the motor housing 10. The electric motor 100 including the stator 110 and the rotor 120 can be a general electric motor.

The compressor 200 includes a compressor wheel 210 mounted on the shaft 130 and a compressor housing 20 surrounding the compressor wheel 210.

Between the motor housing 10 and the compressor housing 20, an insert 300 is disposed to interconnect the motor housing 10 and the compressor housing 20. At this time, the insert 300 is provided with a bearing 400 that restricts the movement of the shaft 130 rotating together with the rotor 120 in the radial direction r and the axial direction a.

At this time, the above-described insert 300 may be equipped with a support frame 500 that supports the bearing 400 to prevent the bearing 400 from separating from the bearing insertion surface 310 formed in the insert 300.

That is, the bearing 400 is basically inserted into the bearing insertion face 310 formed in the insert 300. In this case, the insertion of the bearing 400 may be performed by a loose fitting It is preferable to insert and mount in an intermediate fitting manner. However, if it is not necessary to separate and replace the bearing 400, it is also possible to insert and mount the bearing 400 in an interference fit manner.

Since the bearing 400 inserted and mounted as described above is supported by the support frame 500 mounted on the insert 300 as described above, the bearing inserted surface 310 of the bearing 400 can be effectively prevented from being detached.

As described above, an insert 300 is provided between the electric motor 100 and the compressor 200, and a bearing 400 is installed in the insert 300. In addition, a separate support for fixing the bearing 400 Since the frame 500 is fastened to the insert 300, even when the shaft 130 rotates at a high speed according to the operation of the electric motor 100, the shaft 130 is rotated in the axial direction a and the radial direction r It is possible to effectively support the shaft 130 so as not to move.

A separate fastening member 530 is provided on the support frame 500 so that the support frame 500 can be disassembled from the insert 300 to separate the bearing 400. The fastening member The support frame 500 and the bearing 400 can be disassembled, replaced, and reassembled if necessary.

It is preferable that a shaft through hole through which the shaft 130 penetrates is formed in the insert 300.

2 and 3, the support frame 500 may be formed with an outer ring pressing surface 510 for pressing the outer ring 410 of the bearing 400 in the axial direction (a).

That is, the outer ring pressing surface 510 extends inward in the radial direction r so as to partially or entirely cover the side surface of the outer ring 410. In this state, when the outer ring pressing surface 510 is formed, 530, the fastening force of the fastening member 530 is applied to the side surface of the outer ring 410, so that the fastening force can be effectively fixed.

The outer ring pressing surface 510 may be formed with a guide surface extending in the axial direction a along the outer circumferential surface of the outer ring 410. 3, a part of the bearing 400 inserted in the insert 300 is exposed to the outside of the bearing insertion surface 310, and the above-mentioned guide surface is exposed to the outside of the bearing 400 And extends to cover a part of the outer ring 410. When the guide surface is formed, the support frame 500 can be disposed at a predetermined position in a process of arranging the guide surface to surround a part of the outer ring 410 when the support frame 500 is mounted, 530) is fastened, the ease of fastening can be improved.

The support frame 500 may be formed with a leakage preventing surface 520 extending radially inward from the outer ring pressing surface 510 and disposed adjacent to the outer circumferential surface of the shaft 130. That is, as described above, it is important to prevent the lubricant applied inside the bearing 400 of the non-lube type from leaking to the outside. For this purpose, the oil leakage preventing surface 520 is formed in the support frame 500. The leakage preventing surface 520 is formed to extend from the outer ring pressing surface 510 inward in the radial direction r so as to surround the outer ring 410 and the side surface of the inner ring 420 of the bearing 400.

At this time, it is preferable that the oil leakage preventing surface 520 is disposed adjacent to the shaft 130 without contacting the outer circumferential surface thereof. This is because the support frame 500 on which the oil leakage prevention surface 520 is formed is mounted on the insert 300 which is a non-rotating configuration, while the shaft 130 rotates at high speed in the operation of the electric motor 100.

A gap is formed between the leakage preventing surface 520 and the outer circumferential surface of the shaft 130. The gap may be formed such that air can pass through but not through the lubricant. With this configuration, even if a high pressure is formed in the bearing 400 by heating the air in the bearing 400 during high-speed rotation of the shaft 130, the pressurized air is discharged through the gap, The high pressure state can be eliminated and the leakage of the lubricant can be effectively prevented even in the process of air escape.

Also, it is possible to effectively prevent foreign matter from entering the inside of the bearing 400 from the outside.

Preferably, the leakage preventing surface 520 is also spaced apart from the inner ring 420 of the bearing 400. As described above, the inner ring 420 of the bearing 400 rotates together with the shaft 130, while the support frame 500 with the oil leakage prevention surface 520 is mounted on the insert 300, which is a non-rotating configuration to be.

3, the step difference d may be formed in a direction in which the oil leakage prevention surface 520 is separated from the inner ring 420 of the bearing 400. [ That is, when the oil leakage preventing surface 520 is extended from the outer ring pressing surface 510 of the support frame 500, the oil leakage preventing surface 520 is formed along the axial direction so as to be separated from the inner ring 420 of the bearing 400 And the step d is formed in a state in which the step difference d is formed.

Alternatively, as shown in FIG. 4, an inclination (?) May be formed in a direction in which the oil leakage prevention surface 520 is separated from the inner ring 420 of the bearing 400. That is to say, when the leakage preventing surface 520 is extended from the outer ring pressing surface 510 of the support frame 500, the mutually spaced distance between the leakage preventing surface 520 and the side surface of the bearing 400 gradually increases So that the inclined angle? Is formed.

The leakage preventing surface 520 may be spaced apart from the inner ring 420 of the bearing 400 so that the leakage preventing surface 520 and the inner ring 420 of the bearing 400 are in contact with each other, It is possible to prevent occurrence of non-friction.

As described above, the distance that the oil leakage preventing surface 520 and the inner ring 420 of the bearing 400 are spaced from each other due to the stepped portion d formed on the oil leakage preventing surface 520 or the inclination? The air can pass through but the lubricant can not pass through. With this structure, the high pressure state inside the bearing 400 can be eliminated at the time of high-speed rotation of the shaft 130, and leakage of the lubricant can be effectively prevented even in the course of air escape.

Also, it is possible to effectively prevent foreign matter from entering the inside of the bearing 400 from the outside.

2 and 3, the shaft 130 has an inner ring insertion face 131 into which the inner ring 420 of the bearing 400 is inserted and an inner ring 420 of the bearing 400 in the axial direction the inner ring pressing surface 132 extending outwardly in the radial direction r from the inner ring insertion surface 131 may be formed so as to press the inner ring pressing surface 132a.

That is, the inner ring 420 of the bearing 400 is basically inserted into the inner ring insertion face 131 formed in the shaft 130, and the insertion of the inner ring 420 at this time facilitates the separation and replacement of the bearing 400 It is preferable to insert or loosely fit or mid-fit. However, if it is not necessary to separate and replace the bearing 400, it is also possible to insert and mount the bearing 400 in an interference fit manner.

When the inner ring 420 is inserted into the shaft 130 in a loose fitting or an intermediate fitting manner, when the shaft 130 is rotated at a high speed, the inner ring insertion surface 131 and the inner ring 420 The inner ring 420 of the bearing 400 may be slid in the axial direction a in the axial direction as described above, The inner ring pressing surface 132 extending outwardly in the radial direction r from the inner ring insertion surface 131 is formed so as to be pressed by the inner ring pressing surface 132. As a result,

5, a lock nut 600 is provided to provide a fastening force for fixing the compressor wheel 210 to the shaft 130. The fastening direction Dn of the lock nut 600, It is preferable that the pressing direction Fb of the pressing surface 132 is formed in mutually opposite directions.

With this configuration, a fastening force is applied so that the shaft 130 moves toward the lock nut 600 by tightening the lock nut 600. In this process, the inner ring pressing surface 132 moves the inner ring 420 with a large force It is possible to effectively prevent a slip phenomenon between the inner ring insertion surface 131 and the inner ring 420 from occurring.

While the present invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, Modifications, deletions, additions and the like may easily suggest other embodiments, but these are also within the scope of the present invention.

10: motor housing 20: compressor housing
100: electric motor 110: stator
120: Rotor 130: Shaft
131: inner ring insertion face 132: inner ring pressing face
200: compressor 210: compressor wheel
300: insert 310: bearing insert face
320: fastening hole 400: bearing
410: outer ring 420: inner ring
500: support frame 510: outer ring pressing face
520: leakage preventing surface 530: fastening member
600: Lock nut a: Axial direction
r: radial direction d: step
θ: Slope Dn: Direction of fastening
Fb: Pressure direction

Claims (9)

delete delete An electric motor having a stator mounted inside the motor housing, a rotor rotating relative to the stator when power is supplied, and a shaft for outputting a rotational force of the rotor;
A compressor having a compressor wheel disposed inside the compressor housing fixedly mounted on the shaft to pressurize the air supplied to the vehicle engine; And
An insert disposed between the motor housing and the compressor housing;
/ RTI >
Wherein the insert is provided with a bearing for restricting radial and axial movement of the shaft,
Wherein the insert is equipped with a support frame for supporting the bearing to prevent it from being disengaged from the bearing insertion face formed in the insert,
Wherein the support frame is provided with an oil-free bearing in which an outer ring pressing surface for pressing the outer ring of the bearing in an axial direction is formed. The method of claim 3,
Wherein the support frame is provided with an oil-less bearing extending radially inward from the pressing surface of the outer ring, wherein the oil-repellent surface is formed adjacent to an outer circumferential surface of the shaft. 5. The method of claim 4,
Wherein the oil leakage preventing surface is provided with an oil-less bearing disposed apart from the inner ring of the bearing. 6. The method of claim 5,
Wherein the oil leakage prevention surface is provided with an oil-less bearing having a stepped portion in a direction in which the oil leakage prevention surface is separated from the inner ring of the bearing. 6. The method of claim 5,
Wherein the oil leakage preventing surface is provided with an oil-free bearing whose inclination is formed in a direction in which the oil leakage preventing surface is spaced from the inner ring of the bearing. An electric motor having a stator mounted inside the motor housing, a rotor rotating relative to the stator when power is supplied, and a shaft for outputting a rotational force of the rotor;
A compressor having a compressor wheel disposed inside the compressor housing fixedly mounted on the shaft to pressurize the air supplied to the vehicle engine; And
An insert disposed between the motor housing and the compressor housing;
/ RTI >
Wherein the insert is provided with a bearing for restricting radial and axial movement of the shaft,
Wherein the insert is equipped with a support frame for supporting the bearing to prevent it from being disengaged from the bearing insertion face formed in the insert,
Wherein the shaft is provided with an inner ring insertion face into which the inner ring of the bearing is inserted and an oil-free bearing formed with an inner ring pressing face extending radially outward from the inner ring insertion face to press the inner ring of the bearing in the axial direction. 9. The method of claim 8,
And a lock nut for providing a fastening force for fixing the compressor wheel to the shaft,
And the non-lubricating bearings are formed in opposite directions to each other in the direction in which the lock nut is fastened and the direction in which the pressing surface of the inner ring is pressed.

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