A semi-floating radial bearing structure for an axial-flow turbocharger

Abstract

The invention discloses a semi-floating radial bearing structure of an axial-flow turbocharger, comprising a bearing shell, a pressure-end sealing end cover, a vortex-end sealing end cover, a pressure-end bearing seat and a vortex-end bearing seat, a rotor shaft, a vortex-end radial bearing, a pressure-end radial bearing and an oil-slinging plate, and a compressor impeller. The vortex-end bearing seat and the vortex-end sealing end cover are fixedly connected to the bearing shell, the pressure-end bearing seat is fixedly connected to the vortex-end bearing seat, the oil-slinging plate is fixed on the rotor shaft, and both the vortex-end radial bearing and the pressure-end radial bearing adopt a three-oil-wedge inner oil film structure and an outer oil film squeeze damper structure. The three-oil-wedge inner oil film structure adopts a structure in which wedge-shaped tiles are evenly distributed circumferentially in the inner hole of the bearing to form an inner oil film with the rotor shaft, and the outer oil film squeeze damper structure is composed of a gap between the outer circle of the bearing and the inner hole of the vortex-end bearing seat or the inner hole of the pressure-end bearing seat to form an outer oil film with the inner hole of the vortex-end bearing seat or the inner hole of the pressure-end bearing seat. The pressure-end radial bearing is also provided with a thrust bearing structure along the axial direction to form a thrust bearing pair with the oil-slinging plate.

Description

Technical Field

[0001] The invention relates to the technical field of axial-flow turbochargers, and in particular to a semi-floating radial bearing structure of an axial-flow turbocharger. Background Art

[0002] Turbocharger is a supporting component of diesel engine, which can effectively improve the output power of diesel engine by working with diesel engine. With the development of modern marine diesel engine towards high power density, the performance index of turbocharger has put forward requirements such as high efficiency, high stability and long life. At present, turbocharger commonly uses fixed sliding radial bearing type, full floating sliding bearing type and rolling bearing type. Among them, fixed sliding bearing is characterized by large load-bearing capacity, but under high speed conditions, oil film agitation will occur in the bearing rotor, which will cause rotor instability, and it is suitable for rotors running at low speed; the characteristic of full floating sliding bearing is to ensure efficient and stable operation of rotor under high speed conditions, and its service life reaches more than 24000h under good lubricating oil supply, but its load-bearing capacity is small; the characteristic of rolling bearing type is large radial load-bearing capacity and small rotational friction resistance, but the mutual wear between its ball bearing body and cage is large during long-term operation, and its effective working life is only about 8000h. Therefore, for large axial flow superchargers, it is necessary to redesign a radial bearing structure with high load-bearing capacity and high efficiency to ensure the safe, reliable and efficient operation of the supercharger rotor. How to design a new semi-floating radial bearing structure is the key to solving the problems existing in the existing radial bearing structure. Summary of the invention

[0003] The purpose of the present invention is to provide a novel axial-flow turbocharger semi-floating radial bearing structure to solve the problem that diesel engines in the prior art require a turbocharger with large single-unit matching power and that the existing bearing structure is difficult to meet the use requirements under heavy load and high-speed rotation conditions. The structure can not only realize the high-speed and stable operation of the fully floating radial bearing rotor, but also improve the radial bearing capacity of the bearing, thereby ensuring that the turbocharger can operate efficiently under heavy load and high-speed conditions.

[0004] In order to achieve the above object, the present invention adopts the following technical solutions:

[0005] A semi-floating radial bearing structure of an axial-flow turbocharger comprises a bearing shell, a pressure-end sealing end cover and a turbine-end sealing end cover arranged at the front and rear ends of the bearing shell, a pressure-end bearing seat and a turbine-end bearing seat arranged inside the bearing shell, a rotor shaft rotatably supported on the pressure-end bearing seat and the turbine-end bearing seat, and a turbine-end radial bearing, a pressure-end radial bearing and an oil-slinging plate, and a compressor impeller sleeved on the rotor shaft, the turbine-end bearing seat and the turbine-end sealing end cover are respectively fixedly connected to the bearing shell, the pressure-end bearing seat is fixedly connected to the turbine-end bearing seat, the pressure-end radial bearing is installed in the pressure-end bearing seat, the turbine-end radial bearing is installed in the turbine-end bearing seat, the oil-slinging plate is fixed on the rotor shaft and limited by the rotor shaft, and the turbine-end radial bearing and the pressure-end radial bearing are both A three-oil wedge inner oil film structure and an outer oil film squeeze damper structure are used. The three-oil wedge inner oil film structure adopts a structure in which wedge-shaped tiles are evenly distributed circumferentially in the inner hole of the bearing, and an inner oil film is formed between the three-oil wedge inner oil film structure and the rotor shaft to support the high-speed operation of the rotor shaft. The outer oil film squeeze damper structure is composed of a gap between the outer circle of the bearing and the inner hole of the turbine end bearing seat or the inner hole of the pressure end bearing seat, and an outer oil film is formed between the three-oil wedge inner oil film structure and the inner hole of the turbine end bearing seat or the inner hole of the pressure end bearing seat. Through the damping effect of the squeeze oil film, the turbine end radial bearing slides slowly in the circumferential direction relative to the turbine end bearing seat, and the pressure end radial bearing slides slowly in the circumferential direction relative to the pressure end bearing seat; the pressure end radial bearing is also provided with a thrust bearing structure along the axial direction, forming a thrust bearing pair with the oil slinger plate to balance the axial thrust of the compressor impeller.

[0006] Furthermore, the three-oil-wedge inner oil film structure adopts three wedge-shaped tile structures with preload and offset evenly distributed in the circumferential direction of the inner hole of the bearing, and a first oil groove is axially arranged between two adjacent wedge-shaped tiles to provide sufficient oil supply to the oil wedge structure when the rotor rotates at high speed. The first oil groove is also provided with an oil drain groove to remove particulate impurities in the lubricating oil.

[0007] Furthermore, annular oil grooves are circumferentially provided on the outer circles of the bearings of the vortex end radial bearing and the pressure end radial bearing, and oil holes are evenly distributed on the annular oil grooves. The oil holes on the vortex end bearing connect the bearing oil circuit with the oil supply channel of the vortex end bearing seat, and the oil holes on the pressure end bearing connect the bearing oil circuit with the oil supply channel of the pressure end bearing seat. A first flange is also provided at one end of the vortex end radial bearing, and a second flange is also provided at one end of the pressure end radial bearing. Stop pin holes are evenly distributed along the circumference of the first flange and the second flange, and stop pins are inserted into the stop pin holes. The stop pins are used to make the vortex end radial bearing and the vortex end bearing seat, and the pressure end radial bearing and the pressure end bearing seat slide slowly along the circumference to form an external oil film extrusion damping effect, and the thrust bearing structure is installed in the inner hole of the second flange of the pressure end radial bearing.

[0008] Furthermore, the thrust bearing structure adopts an inclined-plane tile structure, which is arranged at one end of the pressure-end radial bearing close to the oil-flinging plate to form a thrust bearing pair with the oil-flinging plate. A second oil groove is radially provided between two adjacent inclined-plane tile structures, and an oil passage leading to the thrust bearing is axially provided on the inner wall of the thrust bearing to provide sufficient oil supply for the thrust bearing.

[0009] Furthermore, a sealing groove is provided on the turbine end sealing end cover, which forms a labyrinth sealing structure together with the turbine end air seal sleeved on the rotor shaft, for preventing high-temperature combustion gas from entering the turbine end; an oil baffle plate and an oil return groove are also provided on the turbine end sealing end cover, which together with the turbine end air seal form an oil seal structure for preventing the lubricating oil in the turbine end radial bearing from entering the turbine combustion gas working area, and three bosses are evenly distributed along the circumferential direction on the end surface of the turbine end sealing end cover close to the turbine end radial bearing, which correspond to the position of the stop pin, for preventing the stop pin of the turbine end radial bearing from vibrating and falling off and colliding with the rotor during the movement of the rotor.

[0010] Furthermore, the oil-flinging plate is arranged between the compression end radial bearing and the compression end sealing end cover, and is tightened on the rotor shaft through the compressor impeller, and is limited by the step surface on the rotor shaft, so as to maintain a reasonable working oil film gap between the oil-flinging plate and the thrust bearing structure of the compression end radial bearing; the oil-flinging plate and the compression end sealing end cover constitute an oil-flinging and sealing lubricating oil structure, which is used to prevent the lubricating oil of the compression end radial bearing from entering the working area of ​​the compressor impeller, and the compressor impeller and the compression end sealing end cover are provided with a labyrinth sealing groove on the fitting end faces, which is used to seal the high-pressure working gas at the compressor end and prevent it from entering the lubricating oil chamber of the bearing shell and causing cavitation and deterioration of the lubricating oil.

[0011] Furthermore, an oil supply channel leading to the pressure end radial bearing is axially arranged below the pressure end bearing seat, and an oil supply channel leading to the pressure end radial bearing is arranged along the upper right side of the lower part of the vortex end bearing seat.

[0012] Furthermore, an oil inlet hole and an oil return hole are arranged at the bottom of the bearing shell, and a cavity is arranged inside.

[0013] Furthermore, fourteen of the inclined-flat tile structures are provided.

[0014] Beneficial effects of the present invention:

[0015] 1. The radial bearing (vortex end and pressure end) of the present invention adopts a three-oil wedge inner oil film structure with preload and an outer oil film squeeze damper structure. The wedge-shaped tile length of the three-oil wedge inner oil film structure of the bearing inner hole reaches 100 degrees, which maximizes the oil film area of ​​the radial bearing and the rotor shaft, controls the maximum oil film pressure below 10Mpa, and effectively controls the temperature rise of the oil film bearing. An outer oil film squeeze damper structure is adopted between the outer circle of the bearing and the bearing seat, so that the radial bearing and the bearing seat can only slide in a small range, reducing the vibration of the rotor shaft during high-speed operation. This structure can not only realize the high-speed and stable operation of the fully floating radial bearing rotor, but also improve the bearing capacity in the radial direction of the bearing, solve the technical problem that the bearing structure of the bearing-rotor system needs to take into account stability, large bearing capacity and long life at the same time under heavy load and high-speed rotation conditions, and ensure the high-efficiency and reliable operation of the large supercharger rotor.

[0016] 2. The end face of the radial bearing at the pressure end is provided with an axial thrust bearing structure, which effectively balances the axial force of the compressor end and the thrust turbine end during the operation of the rotor system, and prevents the rotor shaft vortex end from moving toward the pressure end.

[0017] 3. The setting of turbine end seal and oil seal structure effectively prevents high-temperature end combustion gas from entering the turbine end radial bearing, prevents high-temperature burning of bearing lubricating oil from causing bearing failure, and effectively prevents turbine end lubricating oil from entering the turbine working area.

[0018] 4. The oil-slinging plate structure of the present invention has a thrust bearing function and an oil-slinging function, thereby preventing the lubricating oil of the compression end radial bearing from entering the working area of ​​the compressor impeller.

[0019] 5. A labyrinth sealing groove is set between the compressor impeller and the compression end sealing cover, which has the function of sealing the high-pressure gas to prevent the high-pressure gas at the compressor impeller end from entering the compression end bearing and causing bearing failure.

[0020] 6. The semi-floating thrust bearing structure of the turbocharger is ingeniously designed, easy to install, has large load-bearing capacity, compact structure and high efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a structural schematic diagram of the present invention;

[0022] Figure 2 for Figure 1 Schematic diagram of the middle A direction;

[0023] Figure 3 It is a schematic diagram of the structure of the vortex end radial bearing;

[0024] Figure 4 It is a schematic diagram of the arrangement of wedge-shaped tiles in the three-oil-wedge inner oil film structure;

[0025] Figure 5 It is a structural schematic diagram of the radial bearing at the pressure end;

[0026] Figure 6 It is a schematic diagram of the inclined-plane pad structure in the pressure end radial bearing;

[0027] Figure 7 This is a schematic diagram of the structure of the turbine end sealing cover.

[0028] Reference numerals

[0029] In the accompanying drawings, 1, bearing shell, 2, pressure end bearing seat, 3, turbine end bearing seat, 4, turbine end sealing end cover, 5, rotor shaft, 6, turbine end gas seal, 7, turbine end radial bearing, 8, pressure end radial bearing, 9, compressor impeller, 10, oil throwing plate, 11, pressure end sealing end cover, 12, stop pin, 13, set screw, 14, damper, 15, wedge-shaped tile, 16, stop pin hole, 17, first oil groove, 18, oil drain groove, 19, annular oil groove, 20, oil through hole, 21, first flange, 22, second flange, 23, thrust bearing structure, 231, inclined-plane tile, 232, second oil groove, 233, oil circuit, 41, oil baffle, 42, oil return groove, 43, boss, 1a, oil inlet hole, 1b, oil return hole, 2a, pressure end radial bearing oil supply channel, 3a, turbine end radial bearing oil supply channel DETAILED DESCRIPTION

[0030] The embodiments of the present invention are further described in detail below with reference to the accompanying drawings.

[0031] See also Figure 1-Figure 6As shown, a semi-floating radial bearing structure of an axial-flow turbocharger comprises a bearing shell 1, a pressure-end sealing end cover 11 and a turbine-end sealing end cover 4 arranged at the front and rear ends of the bearing shell 1, a pressure-end bearing seat 2 and a turbine-end bearing seat 3 arranged inside the bearing shell 1, a rotor shaft 5 rotatably supported on the pressure-end bearing seat 2 and the turbine-end bearing seat 3, and a turbine-end radial bearing 7, a pressure-end radial bearing 8 and an oil-slinging plate 10 and a compressor impeller 9 sleeved on the rotor shaft 5, the turbine-end bearing seat 3 and the turbine-end sealing end cover 4 are respectively fixedly connected to the bearing shell 1 by set screws 13, the pressure-end bearing seat 2 and the turbine-end bearing seat 3 are fixedly connected by set screws 13, the pressure-end radial bearing 8 is installed in the pressure-end bearing seat 2, the turbine-end radial bearing 7 is installed in the turbine-end bearing seat 3, the oil-slinging plate 10 is fixed on the rotor shaft 5 and limited by the rotor shaft 5, and the turbine The end radial bearing 7 and the pressure end radial bearing 8 both adopt a three-oil wedge inner oil film structure and an outer oil film squeeze damper structure. The three-oil wedge inner oil film structure adopts a structure in which wedge-shaped tiles 15 are evenly distributed circumferentially in the inner hole of the bearing, and an inner oil film is formed between the structure and the rotor shaft 5 to support the high-speed operation of the rotor shaft 5. The outer oil film squeeze damper 14 structure is composed of a gap between the outer circle of the bearing and the inner hole of the vortex end bearing seat 3 or the inner hole of the pressure end bearing seat 2, and an outer oil film is formed between the structure and the inner hole of the vortex end bearing seat 3 or the inner hole of the pressure end bearing seat 2. Through the squeeze oil film damping effect, the vortex end radial bearing 7 relative to the vortex end bearing seat 3 and the pressure end radial bearing 8 relative to the pressure end bearing seat 2 slide slowly in the circumferential direction; the pressure end radial bearing 8 is also provided with a thrust bearing structure 24 along the axial direction, forming a thrust bearing pair with the oil slingering plate 10 to balance the axial thrust of the compressor impeller 9.

[0032] like Figures 3 to 5 As shown, in the present invention, the three-oil-wedge inner oil film structure adopts a structure in which three preloaded and offset wedge-shaped pads 15 are evenly distributed in the circumferential direction of the inner hole of the bearing, and the length of the wedge-shaped pads 15 reaches 100 degrees, which maximizes the oil film area and controls the maximum oil film pressure below 10Mpa to control the temperature rise of the oil film bearing. At the same time, a first oil groove 17 is axially provided between two adjacent wedge-shaped pads 15 to facilitate providing sufficient oil supply to the oil wedge structure when the rotor shaft 5 rotates at high speed. An oil drain groove 18 is also provided on the first oil groove 17 to remove particulate impurities in the lubricating oil.

[0033] Annular oil grooves 19 are circumferentially provided on the outer circles of the vortex-end radial bearing 7 and the pressure-end radial bearing 8, and oil holes 20 are evenly distributed on the annular oil grooves 19. The oil holes 20 on the vortex-end radial bearing connect the bearing oil circuit with the oil supply channel 3a of the vortex-end bearing seat, and the oil holes 20 on the pressure-end bearing connect the bearing oil circuit with the oil supply channel 2a of the pressure-end bearing seat. A first flange 21 is also provided at one end of the vortex-end radial bearing 7, and a second flange 22 is also provided at one end of the pressure-end radial bearing 8. Stop pin holes 16 are evenly distributed on the first flange 21 and the second flange 22 along the circumferential direction, and stop pins 12 are inserted into the stop pin holes 16. The stop pins 12 are used to make the vortex-end radial bearing 7 and the vortex-end bearing seat 3, and the pressure-end radial bearing 8 and the pressure-end bearing seat 2 slide slowly along the circumferential direction, forming an external oil film extrusion damping effect, and the thrust bearing structure 23 is installed in the inner hole of the second flange 22 of the pressure-end radial bearing.

[0034] like Figure 5 , Figure 6 As shown, the thrust bearing structure 23 in the present invention adopts fourteen inclined-plane tile structures, which are arranged at one end of the pressure-end radial bearing 8 close to the oil-slinging plate 10 to form a thrust bearing pair with the oil-slinging plate 10. A second oil groove 232 is radially provided between two adjacent inclined-plane tile 231 structures, and an oil passage 233 leading to the thrust bearing is axially provided on the inner wall of the thrust bearing. Oil is supplied through the pressure-end radial bearing to ensure sufficient oil supply to the thrust bearing.

[0035] like Figure 1 As shown, the turbine end sealing end cover 4 is provided with a sealing groove, which forms a labyrinth sealing structure together with the turbine end gas seal 6 sleeved on the rotor shaft, which is used to prevent high-temperature combustion gas from entering the turbine end, causing the turbine end bearing oil film to fail due to high-temperature burning; the turbine end sealing end cover 4 is also provided with an oil baffle plate 41 and an oil return groove 42, which together with the turbine end gas seal 6 form an oil seal structure, which is used to prevent the lubricating oil in the turbine end radial bearing 7 from entering the turbine combustion gas working area and causing combustion accidents. The turbine end sealing end cover 4 is close to the end face of the turbine end radial bearing 7 and is evenly distributed along the circumferential direction. Three bosses 43 are corresponding to the position of the stop pin 12 to prevent the stop pin 12 on the turbine end radial bearing from vibrating and falling off during the movement of the rotor and colliding with the rotor to cause an accident.

[0036] like Figure 1As shown, the oil-slinging plate 10 is arranged between the compression end radial bearing 8 and the compression end sealing end cover 11, and is pressed against the rotor shaft 5 by the compressor impeller 9. The step surface on the rotor shaft 5 is used to limit the position, so as to ensure that a reasonable working oil film gap is maintained between the oil-slinging plate 10 and the thrust bearing structure 24 of the compression end radial bearing; at the same time, the oil-slinging plate 10 and the compression end sealing end cover 11 form an oil seal working structure for oil throwing and sealing lubricating oil, so as to prevent the lubricating oil of the compression end radial bearing 8 from entering the working area of ​​the compressor impeller 9 and affecting the working efficiency and life of the compressor. The compressor impeller 9 and the compression end sealing end cover 11 are provided with a labyrinth sealing groove on the fitting end surface, which is used to seal the high-pressure working gas at the compressor end and prevent it from entering the lubricating oil chamber of the bearing shell to cause cavitation and deterioration of the lubricating oil, thereby ensuring the normal operation of the oil film of the compression end radial bearing 8.

[0037] The pressure end bearing seat 2 provides an installation position and an oil supply channel 2a for the pressure end radial bearing 8. The oil supply channel 2a is arranged axially at the lower part of the pressure end bearing seat 2 and is connected to the oil hole 20 on the pressure end radial bearing 8. The vortex end bearing seat 3 provides an installation position and an oil supply channel 3a for the vortex end radial bearing 7. The oil supply channel 3a is arranged at the lower part of the vortex end bearing seat 3 along the upper right side and is connected to the oil hole 20 on the vortex end radial bearing 7.

[0038] like Figure 1 , Figure 2 As shown, the bottom of the bearing shell 1 is provided with an oil inlet hole 1a and an oil return hole 1b. Oil is introduced from the bottom of the bearing shell to facilitate the establishment of oil supply pressure and sufficient oil supply. The interior of the bearing shell 1 is designed as a larger cavity to facilitate heat dissipation of the bearing structure.

[0039] The working principle of the semi-floating radial bearing structure of the present invention is as follows: when the rotor shaft rotates at high speed, the pressurized lubricating oil continuously enters and flows out of the inner hole of the bearing and forms a three-oil wedge structure with the rotor shaft to form a high-pressure oil film to support the operation of the rotor; at the same time, the pressurized lubricating oil enters the gap between the outer circle of the bearing and the bearing seat hole. Due to the limitation of the bearing stop pin, the radial bearing can only slide slightly in the bearing seat hole, generating an extrusion oil film damping effect, thereby improving the stability of the radial bearing, increasing the bearing load-bearing capacity, and meeting the design technical requirements of high efficiency, long life, and large-scale superchargers; at the same time, an oil seal and an air seal structure are provided at the compression / turbulence end to ensure the safe and reliable operation of the rotor.

[0040] Finally, it should be noted that the above preferred embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail through the above preferred embodiments, those skilled in the art should understand that various changes can be made in form and details without departing from the scope defined by the claims of the present invention.

Claims

1. A semi-floating radial bearing structure of an axial-flow turbocharger, comprising a bearing shell, a pressure end sealing end cover and a turbine end sealing end cover arranged at the front and rear ends of the bearing shell, a pressure end bearing seat and a turbine end bearing seat arranged inside the bearing shell, a rotor shaft rotatably supported on the pressure end bearing seat and the turbine end bearing seat, and a turbine end radial bearing, a pressure end radial bearing and an oil slinger plate, and a compressor impeller sleeved on the rotor shaft, the turbine end bearing seat and the turbine end sealing end cover are respectively fixedly connected to the bearing shell, the pressure end bearing seat is fixedly connected to the turbine end bearing seat, the pressure end radial bearing is installed in the pressure end bearing seat, the turbine end radial bearing is installed in the turbine end bearing seat, the oil slinger plate is fixed on the rotor shaft and limited by the rotor shaft, and is characterized in that: The turbine end radial bearing and the pressure end radial bearing both adopt a three-oil wedge inner oil film structure and an outer oil film squeeze damper structure. The three-oil wedge inner oil film structure adopts a structure in which wedge-shaped tiles are evenly distributed circumferentially in the inner hole of the bearing, and an inner oil film is formed between the three-oil wedge inner oil film structure and the rotor shaft to support the high-speed operation of the rotor shaft. The outer oil film squeeze damper structure is composed of a gap between the outer circle of the bearing and the inner hole of the turbine end bearing seat or the inner hole of the pressure end bearing seat, and an outer oil film is formed between the three-oil wedge inner oil film structure and the inner hole of the turbine end bearing seat or the inner hole of the pressure end bearing seat. Through the squeeze oil film damping effect, the turbine end radial bearing slides slowly in the circumferential direction relative to the turbine end bearing seat, and the pressure end radial bearing slides slowly in the circumferential direction relative to the pressure end bearing seat. The pressure end radial bearing is also provided with a thrust bearing structure along the axial direction, which forms a thrust bearing pair with the oil slinger plate to balance the axial thrust of the compressor impeller.

2. The semi-floating radial bearing structure of an axial-flow turbocharger according to claim 1, characterized in that: The three-oil-wedge inner oil film structure adopts three preloaded and offset wedge-shaped tile structures evenly distributed in the circumferential direction of the inner hole of the bearing, and a first oil groove is axially arranged between two adjacent wedge-shaped tiles to provide sufficient oil supply to the oil wedge structure when the rotor rotates at high speed. The first oil groove is also provided with an oil drain groove to remove particulate impurities in the lubricating oil.

3. The semi-floating radial bearing structure of an axial-flow turbocharger according to claim 1, characterized in that: Annular oil grooves are circumferentially provided on the outer circles of the vortex end radial bearing and the pressure end radial bearing, and oil holes are evenly distributed on the annular oil grooves. The oil holes on the vortex end bearing connect the bearing oil circuit with the oil supply channel of the vortex end bearing seat, and the oil holes on the pressure end bearing connect the bearing oil circuit with the oil supply channel of the pressure end bearing seat. A first flange is also provided at one end of the vortex end radial bearing, and a second flange is also provided at one end of the pressure end radial bearing. Stop pin holes are evenly distributed along the circumference of the first flange and the second flange, and stop pins are inserted into the stop pin holes. The stop pins are used to make the vortex end radial bearing and the vortex end bearing seat, and the pressure end radial bearing and the pressure end bearing seat slide slowly along the circumference to form an external oil film extrusion damping effect, and the thrust bearing structure is installed in the inner hole of the second flange of the pressure end radial bearing.

4. The semi-floating radial bearing structure of an axial-flow turbocharger according to claim 3, characterized in that: The thrust bearing structure adopts an inclined-plane tile structure, which is arranged at one end of the pressure-end radial bearing close to the oil-flinging plate to form a thrust bearing pair with the oil-flinging plate. A second oil groove is radially arranged between two adjacent inclined-plane tile structures, and an oil passage leading to the thrust bearing is axially arranged on the inner wall of the thrust bearing to provide sufficient oil supply for the thrust bearing.

5. The semi-floating radial bearing structure of an axial-flow turbocharger according to claim 3, characterized in that: The turbine end sealing end cover is provided with a sealing groove, which forms a labyrinth sealing structure together with the turbine end air seal sleeved on the rotor shaft, which is used to prevent high-temperature combustion gas from entering the turbine end; the turbine end sealing end cover is also provided with an oil baffle plate and an oil return groove, which together with the turbine end air seal form an oil seal structure, which is used to prevent the lubricating oil in the turbine end radial bearing from entering the turbine combustion gas working area, and the end surface of the turbine end sealing end cover close to the turbine end radial bearing is evenly distributed with three bosses along the circumferential direction, corresponding to the position of the stop pin, which is used to prevent the stop pin of the turbine end radial bearing from vibrating and falling off and colliding with the rotor during the movement of the rotor.

6. The semi-floating radial bearing structure of an axial-flow turbocharger according to claim 1, characterized in that: The oil-slinging plate is arranged between the compression end radial bearing and the compression end sealing end cover, and is tightened on the rotor shaft through the compressor impeller, and is limited by the step surface on the rotor shaft, so as to maintain a reasonable working oil film gap between the oil-slinging plate and the thrust bearing structure of the compression end radial bearing; the oil-slinging plate and the compression end sealing end cover constitute an oil-slinging and sealing lubricating oil structure, which is used to prevent the lubricating oil of the compression end radial bearing from entering the working area of ​​the compressor impeller; the compressor impeller and the compression end sealing end cover are provided with a labyrinth sealing groove on the fitting end faces, which is used to seal the high-pressure working gas at the compressor end and prevent it from entering the lubricating oil chamber of the bearing shell and causing cavitation and deterioration of the lubricating oil.

7. The semi-floating radial bearing structure of an axial-flow turbocharger according to claim 1, characterized in that: An oil supply passage leading to the pressure end radial bearing is axially arranged below the pressure end bearing seat, and an oil supply passage leading to the pressure end radial bearing is arranged along the upper right side of the lower part of the vortex end bearing seat.

8. The semi-floating radial bearing structure of an axial-flow turbocharger according to claim 1, characterized in that: The bottom of the bearing shell is provided with an oil inlet hole and an oil return hole, and a cavity is provided inside.

9. The semi-floating radial bearing structure of an axial-flow turbocharger according to claim 4, characterized in that: Fourteen of the slope-plane tile structures are provided.

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