WO2020122304A1

WO2020122304A1 - Electric turbocharger having oilless bearing

Info

Publication number: WO2020122304A1
Application number: PCT/KR2018/016289
Authority: WO
Inventors: 김기용; 안진호
Original assignee: (주)계양정밀
Priority date: 2018-12-13
Filing date: 2018-12-20
Publication date: 2020-06-18
Also published as: KR101969789B1

Abstract

The present invention relates to an electric turbocharger having an oilless bearing and, more specifically, to an electric turbocharger having an oilless bearing, wherein lubricant applied to the inside of a bearing does not leak toward an electric motor when a pressure difference between a compressor and the electric motor is generated during an operation of a turbocharger, and the bearing that is fixed in the turbocharger can be disassembled, replaced, and reassembled, as necessary.

Description

Electric supercharger with oil-free bearing

The present invention relates to an electric supercharger equipped with a lubrication-free bearing, and more specifically, even if a pressure difference occurs between the compressor and the electric motor during operation of the turbocharger, the lubricant applied inside the bearing does not leak to the electric motor side, and is necessary. It relates to an electric supercharger equipped with a lubrication-free bearing capable of disassembling, replacing, and reassembling the bearing fixed inside the turbocharger.

In general, a power generating device such as an engine that generates a driving force is equipped with various devices to improve the efficiency of power, for example, a turbocharger rotates a turbine using the energy of exhaust gas, and the turbine As a device that pressurizes air through a connected compressor, it is possible to increase the engine power by about 20 to 30% by improving the filling efficiency of the engine by supplying pressurized air to the combustion chamber of the engine.

However, in such a conventional turbocharger, since the turbine and the compressor are connected to the same rotating shaft, torque change is severely caused according to the amount of exhaust gas, and thus it is difficult to pressurize the air constantly.

To solve this, research and development have been conducted on an electric turbocharger that pressurizes air and supplies it to an engine by rotating a rotating shaft connected to a compressor using an electric motor instead of a turbine.

The electric turbocharger is provided with a ball bearing that supports the rotating shaft so that the rotating shaft connected to the compressor wheel does not move in the axial and radial directions. In the case of a non-lubricated turbocharger that does not separately supply lubricant among the electric turbochargers, the durability of the ball bearing Lubricant is pre-applied to the inside for securing.

However, such a turbocharger had a phenomenon in which the lubricant inside the ball bearing leaked to the side of the electric motor due to a pressure difference between the compressor and the electric motor during the operation process, thereby causing the problem of damage to the ball bearing and the rotating parts in the turbocharger. .

In addition, the ball bearing is fixed in such a way that the inner ring of the ball bearing is pressed into the rotating shaft and the outer ring is pressed into the housing of the turbocharger so that the ball bearing effectively supports the rotating shaft. In case of damage, there was a problem that it was impossible to disassemble, replace, and reassemble it.

Therefore, there is a need to improve these problems.

The technical problem to be solved in the present invention is to provide an electric supercharger equipped with a lubrication-free bearing that does not leak lubricant inside the bearing to the electric motor side even when a pressure difference occurs between the compressor and the electric motor during operation of the turbocharger. .

In addition, it is to provide an electric supercharger equipped with a lubrication-free bearing that can be disassembled, replaced, and reassembled as necessary even after the bearing is fixed inside the turbocharger.

An electric supercharger equipped with a lubrication-free bearing according to an aspect of the present invention for solving the above technical problem is a stator mounted inside the motor housing, a rotor rotating relative to the stator when power is supplied, and the rotor An electric motor provided with a shaft through which the former rotational force is output, and a compressor provided with a compressor wheel disposed inside the compressor housing fixedly mounted on the shaft to pressurize air supplied to a vehicle engine, and the motor housing and the It includes an insert disposed between the compressor housing, the insert is provided with a bearing to limit the 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 departure from the bearing insertion surface formed in the insert.

An outer ring pressing surface for pressing the outer ring of the bearing in the axial direction may be formed on the support frame.

In addition, the support frame may be formed to extend from the outer ring pressing surface in the radial direction, the leakage preventing surface disposed adjacent to the outer peripheral surface of the shaft.

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

In addition, a step may be formed on the leakage preventing surface in a direction in which the leakage preventing surface is spaced apart from the inner ring of the bearing.

Alternatively, a slope may be formed on the leakage preventing surface in a direction in which the leakage preventing surface is spaced apart from the inner ring of the bearing.

In addition, the shaft may be formed with an inner ring inserting surface into which the inner ring of the bearing is inserted, and an inner ring pressing surface extending radially outward from the inner ring inserting surface to urge the inner ring of the bearing in the axial direction.

At this time, a lock nut is provided to provide a fastening force so that the compressor wheel is fixedly mounted on the shaft, and the fastening direction of the lock nut and the pressing direction of the inner ring pressing surface may be formed in opposite directions.

The electric supercharger provided with the lubrication-free bearing of the present invention having the above-described configuration is provided with an insert between the electric motor and the compressor, and a bearing is installed on the insert, but a separate support frame for fixing the bearing is fastened to the insert. Even when the shaft rotates at a high speed according to the operation of the motor, it is possible to effectively support the shaft so that the shaft does not move in the axial and radial directions.

In addition, it is possible to prevent damage to the internal rotational system of the bearing and the electric supercharger by forming a leak-preventing surface to prevent leakage of lubricant inside the bearing in the insert frame.

In addition, by dismantling the support frame from the insert so that the bearing can be separated, it is possible to disassemble, replace, and reassemble it if necessary.

1 is a cross-sectional view showing an electric supercharger according to an embodiment of the present invention.

2 is a cross-sectional view showing a partially disassembled configuration of an electric supercharger according to an embodiment of the present invention.

3 is an enlarged cross-sectional view of part A of FIG. 1.

4 is a cross-sectional view showing a support frame according to another embodiment of the present invention.

5 is a cross-sectional view showing a state in which some components of an electric supercharger according to an embodiment of the present invention are combined.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art to which the present invention pertains can easily practice. The present invention can be implemented in many different forms and is not limited to the embodiments described herein. In the drawings, parts not related to the description are omitted in order to clearly describe the present invention, and the same reference numerals are attached to the same or similar elements throughout the specification.

In this specification, terms such as “include” or “have” are intended to indicate that a feature, number, step, operation, component, part, or combination thereof described in the specification exists, and that one or more other features are present. It should be understood that the existence or addition possibilities of fields or numbers, steps, actions, components, parts or combinations thereof are not excluded in advance.

1 is a cross-sectional view showing an electric supercharger according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view showing a state in which some components of the electric supercharger according to an embodiment are disassembled, and FIG. 3 is FIG. 1 Figure A is an enlarged cross-sectional view of part A, Figure 4 is a cross-sectional view showing a support frame according to another embodiment of the present invention, Figure 5 is a part of the configuration of the electric supercharger according to an embodiment of the present invention combined state It is a sectional view.

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

When the electric motor 100 is supplied with power, the compressor wheel 210 provided in the compressor 200 is rotated. To this end, the electric motor 100 includes a stator 110 mounted inside the motor housing 10. , The rotor 120 is rotated relative to the stator 110, and the shaft 130 is output from the rotational force of the rotor 120 is provided.

That is, when power is supplied to the electric motor 100 and the rotor 120 rotates, the fixed shaft 130 rotates to rotate together with the rotor 120, and the compressor wheel ( 210) is fixedly mounted and pressurizes the air supplied to the compressor 200 while rotating with the shaft 130 to supply it to the engine combustion chamber.

At this time, the stator 110 is fixedly mounted inside the motor housing 10, and thus, the electric motor 100 composed of the stator 110 and the rotor 120 may use a general electric motor.

In addition, the compressor 200 is provided with a compressor wheel 210 that is malfunction-mounted on the above-described shaft 130 and a compressor housing 20 surrounding the compressor wheel 210.

An insert 300 is disposed between the motor housing 10 and the compressor housing 20 to interconnect them. At this time, the insert 300 is provided with a bearing 400 that restricts the shaft 130 rotating with the rotor 120 from moving in the radial direction (r) and the axial direction (a).

In this case, the support frame 500 for supporting the bearing 400 to prevent the bearing 400 from deviating from the bearing insertion surface 310 formed in the insert 300 may be mounted.

That is, the bearing 400 is basically inserted and mounted on the bearing insertion surface 310 formed in the insert 300, wherein the insertion of the bearing 400 is loosely fitted to facilitate separation and replacement of the bearing 400 later, or It is preferred to be inserted and mounted in an intermediate fitting manner. However, when the separation and replacement of the bearing 400 is not required, it is also possible to insert and mount the bearing 400 in a forced fit manner.

In addition, as described above, the bearing 400 is supported by the support frame 500 mounted on the insert 300, as described above, so that the bearing insert surface by external force applied during the high-speed rotation process of the shaft 130 ( It is possible to effectively prevent the bearing 400 from coming off from 310.

As described above, an insert 300 is provided between the electric motor 100 and the compressor 200, and a bearing 400 is installed on the insert 300, but a separate support for fixing the bearing 400 is provided. 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, these shafts 130 are axially (a) and radially (r) It is possible to effectively support the shaft 130 so as not to move.

In addition, 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, and the fastening member ( By forming a fastening hole 320 coupled with the 530, it is possible to disassemble, replace and reassemble the support frame 500 and the bearing 400 as necessary.

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

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

That is, the outer ring pressing surface 510 is formed to extend inward in the radial direction (r) to partially or entirely surround the side surface of the outer ring 410, and thus the fastening member described above in the state where 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, thereby enabling effective fixing.

In addition, a guide surface extending in the axial direction (a) along the outer circumferential surface of the outer ring 410 may be formed on the outer ring pressing surface 510. As shown in FIG. 3, a part of the bearing 400 inserted into the insert 300 is exposed to the outside of the bearing inserting surface 310, and the aforementioned guide surface of the bearing 400 is exposed as described above. It is formed to extend to surround a portion of the outer ring 410. When the guide surface is formed in this way, the support frame 500 can be placed in place in the process of arranging the guide surface to surround a portion of the outer ring 410 when the support frame 500 is mounted, and then the fastening member ( 530), the ease of fastening can be improved.

In addition, the support frame 500 may be formed to extend from the outer ring pressing surface 510 in the radial direction (r), the leakage preventing surface 520 disposed adjacent to the outer peripheral surface of the shaft 130. That is, as described above, it is important for the lubricant-free bearing 400 to prevent the lubricant applied therein from leaking to the outside, and for this purpose, a leakage preventing surface 520 is formed on the support frame 500. The leakage preventing surface 520 is formed to extend inward in the radial direction r from the outer ring pressing surface 510 and is configured to surround side surfaces of the outer ring 410 and the inner ring 420 of the bearing 400.

At this time, the leakage preventing surface 520 is preferably not disposed in contact with the outer circumferential surface of the shaft 130. This is because the shaft 130 rotates at a high speed during the operation of the electric motor 100, while the support frame 500 on which the leakage preventing surface 520 is formed is mounted on the insert 300 having a non-rotating configuration.

A gap is formed between the leak-preventing surface 520 and the outer circumferential surface of the shaft 130, and it is preferable that the gap is formed in a size that air can pass through but lubricant cannot. When configured in this way, the air inside the bearing 400 is heated during high-speed rotation of the shaft 130, and even if a high pressure is formed inside the bearing 400, the pressurized air escapes through the above-described gap while the inside of the bearing 400 is removed. The high pressure state can be eliminated, and leakage of the lubricant can be effectively prevented even in the process of evacuating air.

In addition, it is possible to effectively block foreign matter from entering the inside of the bearing 400 from the outside.

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

To this end, as shown in FIG. 3, a step d may be formed in a direction in which the leakage preventing surface 520 is spaced apart from the inner ring 420 of the bearing 400. That is, along the axial direction such that the leakage preventing surface 520 is spaced apart from the inner ring 420 of the bearing 400 when the leakage preventing surface 520 is extended from the outer ring pressing surface 510 of the support frame 500. The step (d) is formed in an extended state.

Alternatively, as illustrated in FIG. 4, an inclination θ may be formed in a direction in which the leakage preventing surface 520 is spaced apart from the inner ring 420 of the bearing 400. That is, when the leakage preventing surface 520 is extended from the outer ring pressing surface 510 of the support frame 500, the distance between the leakage preventing surface 520 and the side surfaces of the bearing 400 gradually increases. So that the slope (θ) is formed is formed to extend.

The leak-prevention surface 520 may be spaced apart from the inner ring 420 of the bearing 400 in the above-described manner, through which the leak-prevention surface 520 and the inner ring 420 of the bearing 400 contact each other. It is possible to prevent the occurrence of friction.

In addition, as described above, the distance between the leak prevention surface 520 and the inner ring 420 of the bearing 400 due to the step d being formed on the leak prevention surface 520 or the inclination θ is formed is The air can pass but the lubricant can be formed to a size that cannot. With this configuration, the high pressure state inside the bearing 400 can be eliminated when the shaft 130 rotates at a high speed, and leakage of the lubricant can be effectively prevented even in the process of evacuating air.

In addition, the shaft 130, as shown in Figures 2 and 3, the inner ring 420 of the inner ring 420 of the bearing 400 is inserted, and the inner ring 420 of the bearing 400, the axial direction ( An inner ring pressing surface 132 extending from the inner ring inserting surface 131 to the outside in the radial direction r may be formed so as to pressurize to a).

That is, the inner ring 420 of the bearing 400 is basically inserted and mounted on the inner ring inserting surface 131 formed on the shaft 130, and the insertion of the inner ring 420 is easy to remove and replace the bearing 400 later. It is preferred that it is inserted and mounted in a loose fit or medium fit manner. However, when the separation and replacement of the bearing 400 is not required, it is also possible to insert and mount the bearing 400 in a forced fit manner.

In addition, when the inner ring 420 is inserted into the shaft 130 by loose fitting or intermediate fitting, when the shaft 130 rotates at a high speed, the inner ring inserting surface 131 of the shaft 130 and the inner ring 420 ) While the slip phenomenon occurs, the support of the shaft 130 may not be stably performed, but as described above, the inner ring 420 of the bearing 400 is axially (a) in the shaft 130. If the inner ring pressing surface 132 extending radially (r) outward from the inner ring inserting surface 131 to pressurize ), the support of the shaft 130 can be stably made.

At this time, as shown in Figure 5, the shaft 130 is provided with a lock nut 600 that provides a fastening force so that the compressor wheel 210 is fixed, the fastening direction (Dn) and the inner ring of the lock nut 600 The pressing direction Fb of the pressing surface 132 is preferably formed in opposite directions.

When configured in this way, the fastening force is applied so that the shaft 130 moves toward the lock nut 600 as the lock nut 600 is tightened, and in this process, the inner ring pressing surface 132 uses the inner ring 420 with great force. By pressing, the slip phenomenon between the inner ring insertion surface 131 and the inner ring 420 can be effectively prevented.

Although one embodiment of the present invention has been described above, the spirit of the present invention is not limited to the embodiments presented herein, and those skilled in the art to understand the spirit of the present invention, within the scope of the same spirit, the addition of components, Other embodiments can be easily proposed by changing, deleting, adding, or the like, but this will also be considered to be within the scope of the present invention.

Claims

An electric motor provided with a stator mounted inside the motor housing, a rotor rotating relative to the stator when power is supplied, and a shaft through which the rotational force of the rotor is output;

A compressor having a compressor wheel disposed inside the compressor housing while being fixedly mounted on the shaft to pressurize air supplied to the vehicle engine; And

An insert disposed between the motor housing and the compressor housing;

It includes,

The insert is a motor-driven supercharger equipped with a lubrication-free bearing equipped with a bearing for limiting the radial and axial movement of the shaft.
According to claim 1,

The insert is provided with a non-lubrication bearing equipped with a support frame for supporting the bearing to prevent it from deviating from the bearing insertion surface formed in the insert.
According to claim 2,

The support frame is an electric supercharger equipped with an oil-free bearing having an outer ring pressurizing surface for pressing the outer ring of the bearing in the axial direction.
According to claim 3,

The support frame is provided with an oil-free supercharger that extends radially inward from the pressing surface of the outer ring, and is provided with a lubrication-free bearing that is disposed adjacent to the outer circumferential surface of the shaft.
The method of claim 4,

The leakage preventing surface is an electric supercharger equipped with an oil-free bearing that is spaced apart from the inner ring of the bearing.
The method of claim 5,

The oil leakage prevention surface is provided with an oil-free supercharger having a lubrication-free bearing in which a step is formed in a direction in which the oil leakage prevention surface is spaced apart from the inner ring of the bearing.
The method of claim 5,

The leakage preventing surface is provided with an oil-free supercharger having an oil-free bearing in which a slope is formed in a direction in which the leakage preventing surface is spaced apart from the inner ring of the bearing.
According to claim 2,

The shaft is provided with an inner ring inserting surface into which the inner ring of the bearing is inserted, and an electric supercharger equipped with an oil-free bearing having an inner ring pressing surface extending radially outward from the inner ring inserting surface to press the inner ring of the bearing in the axial direction.
The method of claim 8,

The shaft is provided with a lock nut that provides a fastening force so that the compressor wheel is fixedly mounted,

The fastening direction of the lock nut and the pressing direction of the pressing surface of the inner ring are provided with an oil-free bearing formed in opposite directions to each other.