Turbocharger based on high negative pressure resistant shafting structure

Abstract

This invention relates to the field of internal combustion engine turbocharger technology, specifically a turbocharger based on a shaft system structure with high negative pressure resistance. The turbocharger comprises a bearing housing, a high-speed rotor, a thrust sleeve, a thrust bearing, a shaft seal, and an impeller. The high-speed rotor is housed within the bearing housing, and the impeller, shaft seal, thrust bearing, and thrust sleeve are sequentially and parallelly mounted on the high-speed rotor along the axial direction. The thrust sleeve is independently and fixedly connected to the high-speed rotor via an axial positioning structure. The impeller and shaft seal are independently fixed to the high-speed rotor via a second axial positioning structure. An inner clearance is provided between the inner diameter of the thrust bearing's thrust surface and the high-speed rotor. This invention aims to effectively reduce the inner diameter of the thrust bearing while maintaining constant axial load capacity, thereby directly reducing oil film shear loss during rotation. Simultaneously, it reduces the oil flow entering the turbocharger's negative pressure resistance components, significantly mitigating the risk of oil suction under negative pressure conditions.

Description

Technical Field

[0001] This invention relates to the field of internal combustion engine turbocharging technology, and more specifically to a turbocharger based on a shaft system structure with high resistance to negative pressure. Background Technology

[0002] As a core component for energy conservation and emission reduction in internal combustion engines, the performance and reliability of turbochargers directly determine the engine's power output, fuel economy, and emission compliance. In the high-speed rotating shaft system of a turbocharger, the thrust bearing plays a crucial role in balancing the axial force of the high-speed rotor and limiting axial movement. The rationality of its structural design directly affects the overall mechanical efficiency and operational stability of the turbocharger.

[0003] Industry-specific research and engineering practice have verified that, while maintaining the same axial load capacity, effectively reducing the inner diameter of the thrust bearing can directly reduce oil film shear loss during rotation. Simultaneously, reducing the oil flow rate into the turbocharger's anti-negative pressure components can significantly mitigate the risk of oil suction under negative pressure conditions.

[0004] However, in traditional turbochargers, such as Figure 12 As shown, in order to ensure reliable clamping between the traditional thrust sleeve 01 and the traditional shaft seal 02, the inner diameter of the traditional thrust bearing 03 must be larger than the outer diameter of the connection between the traditional thrust sleeve 01 and the traditional shaft seal 02. This results in the inner radius of the traditional thrust bearing 03 needing to satisfy the dimensional superposition relationship of "shaft radius r + shaft seal connection thickness l + thrust inner clearance s", ultimately leading to a large inner diameter design for the traditional thrust bearing 03. This design has three significant negative effects: Firstly, when the traditional rotor 04 rotates at high speed, the oil film shear area at the inner diameter of the traditional thrust bearing 03 increases, which leads to a significant increase in viscous friction loss, directly reducing the mechanical efficiency of the turbocharger. Moreover, under partial load conditions, this friction loss accounts for a more prominent proportion. Secondly, in order to maintain a stable oil film pressure distribution, a higher oil supply is required, which further increases the workload of the entire machine's lubrication system. Third, the existing shaft structure has a natural weakness in resisting negative pressure under negative pressure conditions at the compressor 04 end (such as rapid engine deceleration, intake system blockage, etc.). When a negative pressure environment is formed at the compressor 04 end, the lubricating oil on the traditional pressure side bearing surface 031 is easily sucked into the compressor, which not only leads to an abnormal increase in oil consumption and carbon buildup on the impeller and compressor flow channel, but may also trigger compressor surge and a vicious cycle of positive feedback of oil suck-in. The traditional solution is usually to add a complex sealing ring or oil baffle at the pressure end, but such designs not only increase oil-gas friction loss, but also bring a heavy cost burden to cost-sensitive turbocharger products.

[0005] In conclusion, the existing technology obviously has inconveniences and defects in practical use, so it is necessary to improve it. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention provides a turbocharger based on a shaft system structure with high negative pressure resistance. This allows for the effective reduction of the thrust bearing inner diameter while maintaining axial load capacity, directly reducing oil film shear loss during rotation. Simultaneously, it reduces the flow of oil entering the turbocharger's negative pressure resistance components, significantly mitigating the risk of oil suction under negative pressure conditions.

[0007] To address the above problems, the present invention provides the following technical solution: A turbocharger based on a shaft system structure with high negative pressure resistance includes a bearing housing, a high-speed rotor, a thrust sleeve, a thrust bearing, a shaft seal, and an impeller. The high-speed rotor is housed in the bearing housing, and the impeller, shaft seal, thrust bearing and thrust sleeve are sequentially and axially arranged side by side on the high-speed rotor. The thrust sleeve is independently and fixedly connected to the high-speed rotor through an axial positioning structure; the impeller and shaft seal are independently fixed to the high-speed rotor through an axial positioning structure; and an inner clearance is provided between the inner diameter of the thrust surface of the thrust bearing and the high-speed rotor.

[0008] As an optimized solution, the thrust bearing has a pressure-side bearing surface and a vortex-side bearing surface on both sides that are connected to the inner clearance of the thrust bearing, and the thrust bearing has an axial oil discharge groove that guides the oil on the pressure-side bearing surface to the vortex-side oil discharge channel.

[0009] As an optimized solution, the thrust bearing is provided with a thrust bearing oil supply hole, and the outlet end of the thrust bearing oil supply hole is connected to the inner clearance of the thrust bearing.

[0010] As an optimized solution, the pressure side bearing surface and the vortex side bearing surface are provided with a number of fan-shaped oil wedges around the circumference, and a radial oil supply groove is provided between adjacent fan-shaped oil wedges. The radial oil supply groove is connected to the inner clearance of the thrust bearing.

[0011] As an optimization scheme, a rotary thrust guide surface is provided on the outer side of the pressure side bearing surface, and the angle between the meridian of the thrust guide surface and the axis of the high-speed rotor shaft pointing to the vortex end is (75-85)°.

[0012] As an optimized solution, the axial positioning structure includes an external thread that mates with the high-speed rotor and the thrust sleeve.

[0013] As an optimized solution, the axial positioning structure includes a thrust sleeve positioning shoulder located on the high-speed rotor, and one end of the thrust sleeve is provided with a thrust sleeve limiting structure that abuts against the thrust sleeve positioning shoulder.

[0014] As an optimized solution, the second axial positioning structure includes a shaft seal positioning shoulder located on the high-speed rotor, and the inner hole of the shaft seal is provided with a shaft seal limiting structure that abuts against the shaft seal positioning shoulder.

[0015] As an optimized solution, the second axial positioning structure includes a locking nut threaded to the end of the high-speed rotor. The locking nut abuts against the impeller nose of the impeller, and the impeller nose is provided with a nose limiting structure to limit the locking nut.

[0016] As an optimized solution, the nose limiting structure includes a positioning groove formed on the end of the impeller nose, one of the opposite sidewalls of the positioning groove penetrates the impeller nose, and the groove width of the other opposite inner wall of the positioning groove is smaller than the pitch circle diameter of the locking nut and larger than the inscribed circle diameter of the locking nut.

[0017] As an optimized solution, the pressure-side bearing surface is provided with a thrust guide surface in a U-shape, and the shaft seal bearing surface is provided with a shaft seal guide surface in a U-shape. The meridian of the shaft seal guide surface is parallel to the meridian of the thrust guide surface and forms a guide gap. The outer diameter of the shaft seal guide surface is smaller than the outer diameter of the thrust guide surface and forms a pressure-side oil unloading gap. The pressure-side oil unloading gap, the guide gap, and the axial oil unloading groove are connected to each other.

[0018] Compared with the prior art, the beneficial effects of the present invention are: The thrust sleeve is fastened to the high-speed rotor using an internal thread and a thrust sleeve limiting structure. The shaft seal limiting structure allows the shaft seal and impeller to be locked together on the high-speed rotor with a lock nut, thus achieving independent axial positioning of the thrust sleeve and shaft seal. This eliminates the clamping part of the traditional thrust sleeve and shaft seal in the traditional turbocharger shaft system structure, and eliminates the dimension of the shaft seal connection thickness l in the existing thrust bearing inner radius that needs to meet the superposition relationship of the three dimensions "rotor radius r + shaft seal connection thickness l + thrust inner clearance s". This structurally achieves the purpose of reducing the inner diameter of the thrust bearing. At the same time, by using the guide gap formed by the shaft seal guide surface and the thrust guide surface, and by setting an axial oil discharge groove on the thrust bearing, the oil thrown out from the pressure side bearing surface is guided to the axial oil discharge groove. Most of the oil then enters the outer oil discharge groove and the vortex side oil discharge channel through the axial oil discharge groove, thereby reducing the amount of oil entering the negative pressure component and thus improving the turbocharger's anti-negative pressure oil leakage characteristics. To prevent the clamping surface between the shaft seal limiting structure and the shaft seal positioning shoulder from being too narrow, which would result in insufficient locking torque for the impeller during operation, a nose limiting structure is set at the impeller nose, which includes a locking nut. When the locking torque of the locking nut is insufficient, the impeller can be jammed by the groove structure to prevent it from slipping and failing. This invention can significantly reduce the inner radius of the thrust surface while maintaining the load-bearing capacity of the turbocharger thrust bearing, thereby greatly improving the friction power consumption of the thrust bearing; and can divert the oil thrown out by the pressure side thrust surface to the vortex side of the thrust surface, reducing the oil flow into the negative pressure component, thereby improving the turbocharger's resistance to negative pressure oil leakage. The present invention features a clever and compact structural design. Without significantly increasing manufacturing costs and complexity, it achieves excellent low power consumption and high resistance to negative pressure through a series of mutually cooperating geometric configuration optimizations. It is particularly suitable for high power density engines with extremely high requirements for efficiency and negative pressure oil leakage resistance, and has significant engineering application value and promotion prospects. Attached Figure Description

[0019] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the accompanying drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. In all the drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, the elements or parts are not necessarily drawn to scale.

[0020] Figure 1 This is a schematic diagram of the structure of the present invention; Figure 2 for Figure 1 An enlarged schematic diagram of part A in the middle; Figure 3 This is a schematic diagram of the axial oil unloading groove of the present invention; Figure 4 This is a schematic diagram of the impeller structure of the present invention; Figure 5 This is a schematic diagram of the thrust guide surface of the present invention; Figure 6 This is a schematic diagram of the oil supply hole of the thrust bearing of the present invention; Figure 7 This is a schematic diagram of the high-speed rotor of the present invention; Figure 8 This is a schematic diagram of the shaft seal structure of the present invention; Figure 9 This is a schematic diagram of the thrust sleeve of the present invention; Figure 10 This is a schematic diagram of the structure of the floating bearing of the present invention; Figure 11 This is a schematic diagram of the bearing body of the present invention; Figure 12 This is a schematic diagram of the existing technology.

[0021] In the diagram: 1-Compressor; 101-Compressor flow channel; 102-Impeller; 1021-Impeller inner bore; 1022-Impeller nose; 1023-Nose limiting structure; 2-Turbine; 201-Turbine volute; 202-Turbine; 3-Negative pressure assembly; 301-Sealing ring; 302-Impeller sleeve; 303-Oil baffle; 304-Retaining ring; 4-High-speed rotor; 401-Four-stage stepped shaft; 4011-Thickest shaft; 4012-Second thickest shaft; 4013-External thread one; 4014-Third thickest shaft; 4015-Outer diameter of third thickest shaft ; 4016 - Fourth coarse shaft; 4017 - External thread two; 402 - Thrust sleeve; 4021 - Internal thread one; 4022 - Inner diameter of thrust sleeve; 4023 - Bearing surface of thrust sleeve; 4024 - Outer edge of thrust sleeve; 4025 - Clamping plane; 4026 - Limiting structure of thrust sleeve; 403 - Shaft seal; 4031 - Inner diameter of shaft seal one; 4032 - Inner diameter of shaft seal two; 4033 - Limiting structure of shaft seal; 4034 - Bearing surface of shaft seal; 4035 - Guide surface of shaft seal; 4036 - Outer diameter of guide surface of shaft seal; 404 - Locking nut; 4041 - Lock Tightening nut internal thread; 405-Shaft seal positioning shoulder; 406-Thrust sleeve positioning shoulder; 407-Thrust bearing inner clearance; 5-Thrust bearing; 501-Pressure side bearing surface; 502-Vortex side bearing surface; 503-Thrust surface inner diameter; 504-Pressure side thrust surface outer diameter; 505-Vortex side thrust surface outer diameter; 506-Axial oil drain groove; 507-Axial oil drain groove outer diameter; 508-Axial oil drain groove inner diameter; 509-Thrust bearing oil supply hole; 510-Thrust bearing plate; 511-Fan-shaped oil wedge; 512-Radial oil supply groove; 513-Thrust guide. Surface; 514-Guide gap; 515-Pressure side oil unloading gap; 6-Floating bearing; 601-Floating inner diameter; 602-Floating bearing outer diameter; 603-Floating notch; 7-Bearing body; 701-Bearing seat; 702-Thrust bearing clamping surface; 703-Oil supply hole; 704-Inner oil unloading groove; 705-Outer oil unloading groove; 706-Oil unloading groove partition plate; 7061-Inner diameter of oil unloading groove partition plate; 7062-Outer diameter of oil unloading groove partition plate; 707-Oil return chamber; 708-Bowl-shaped plug; 709-Vortex side oil unloading channel; 710-Pressure side oil unloading channel. Detailed Implementation

[0022] The embodiments of the technical solution of the present invention will now be described in detail with reference to the accompanying drawings. These embodiments are merely illustrative of the technical solution of the present invention and are therefore intended to limit the scope of protection of the present invention.

[0023] like Figures 1 to 11 As shown, a turbocharger based on a shaft system structure with high negative pressure resistance includes a compressor 1, a turbine 2, a negative pressure assembly 3, a high-speed rotor 4, a thrust bearing 5, a floating bearing 6, and a bearing housing 7.

[0024] The compressor 1 includes a compressor flow channel 101 and an impeller 102.

[0025] Turbine 2 includes: turbine casing 201 and turbine 202.

[0026] The negative pressure assembly 3 includes: a sealing ring 301, an impeller sleeve 302, an oil baffle 303, and a retaining ring 304.

[0027] The high-speed rotor 4 includes: a four-stage stepped shaft 401, a thrust sleeve 402, a shaft seal 403, and a locking nut 404.

[0028] The thrust sleeve 402 is independently fixed to the high-speed rotor 4 through an axial positioning structure; the impeller 102 and the shaft seal 403 are independently fixed to the high-speed rotor 4 through an axial positioning structure; the inner diameter 503 of the thrust surface of the thrust bearing 5 is provided with an inner clearance 407 between the thrust bearing and the high-speed rotor 4. The turbine 202 is fixedly connected to the thickest shaft 4011 of the four-stage stepped shaft 401 by welding; the second thick shaft 4012 is clearance-fitted with the floating inner diameter 601 of the floating bearing 6; the pressure end of the second thick shaft 4012 is machined with an external thread 4013, which forms a threaded fit with the internal thread 4021 of the thrust sleeve 402; the axial direction of the turbine end of the third thick shaft 4014 starts from the pressure end of the external thread 4013; the outer diameter 4015 of the third thick shaft is clearance-fitted with the inner diameter 4031 of the shaft seal and the inner diameter 4022 of the thrust sleeve. The fourth thick shaft 4016 is clearance-fitted with the inner diameter 4032 of the shaft seal and the inner hole 1021 of the impeller; the pressure end of the fourth thick shaft 4016 is machined with an external thread 4017, which forms a threaded fit with the internal thread 4041 of the lock nut.

[0029] The thrust bearing 5 includes: a pressure-side bearing surface 501, a scroll-side bearing surface 502, an inner diameter of the thrust surface 503, an outer diameter of the pressure-side thrust surface 504, an outer diameter of the scroll-side thrust surface 505, an axial oil drain groove 506, an outer diameter of the axial oil drain groove 507, an inner diameter of the axial oil drain groove 508, an oil supply hole for the thrust bearing 509, and a flat plate for the thrust bearing 510. Both the pressure-side bearing surface 501 and the scroll-side bearing surface 502 are composed of 4-8 fan-shaped oil wedges 511, with a radial oil supply groove 512 provided between two adjacent fan-shaped oil wedges 511. An inner clearance 407 for the thrust bearing is formed between the inner diameter of the thrust surface 503 and the outer diameter 4015 of the third coarse shaft.

[0030] A rotary thrust guide surface 513 is provided on the outer side of the pressure side bearing surface 501. The angle between the meridian of the thrust guide surface 513 and the axis of the high-speed rotor shaft pointing to the vortex end is (75-85)°.

[0031] Axial oil unloading grooves 506 are evenly distributed in 2-4 locations in the circumferential direction, and their arrangement should avoid the oil supply hole 509 of the thrust bearing.

[0032] The bearing housing 7 includes: a bearing seat 701, a thrust bearing clamping surface 702, an oil supply hole 703, an inner oil drain groove 704, an outer oil drain groove 705, an oil drain groove partition plate 706, an inner diameter 7061 of the oil drain groove partition plate, an outer diameter 7062 of the oil drain groove partition plate, and an oil return cavity 707. The bearing seat 701 is clearance-fitted with the outer diameter 602 of the floating bearing; a bowl-shaped plug 708 is provided in the inner oil drain groove 704 for clearance-fitting with the floating notch 603 of the floating bearing 6, thereby limiting the floating bearing 6 in the circumferential and axial directions.

[0033] The thrust bearing 5, impeller sleeve 302, and oil baffle 303 are pressed together on the thrust bearing pressing surface 702 by the preload of the retaining ring 304. The inner oil discharge groove 704 and the outer oil discharge groove 705 are connected to the vortex-side oil discharge channel 709. The oil discharge groove partition plate 706 is in close contact with the thrust bearing plate 510, thus separating the inner oil discharge groove 704 from the outer oil discharge groove 705; both the vortex-side oil discharge channel 709 and the pressure-side oil discharge channel 710 are connected to the return oil chamber 707.

[0034] The thrust sleeve bearing surface 4023 that mates with the vortex-side bearing surface 502 is a plane perpendicular to the axial direction; clamping planes 4025 are machined at (3-4) locations on the outer edge 4024 of the thrust sleeve, and the diameter of the inscribed circle formed by the clamping planes 4025 is greater than or equal to the outer diameter 505 of the vortex-side thrust surface; the thrust sleeve limiting structure 4026 is limited by the thrust sleeve positioning shoulder 406 when the thrust sleeve 402 is tightened, and is subjected to the axial preload provided by the thrust sleeve positioning shoulder 406.

[0035] The inner diameter of the shaft seal 403 is larger than that of the inner diameter of the shaft seal 403 by (0.4-0.6) mm. The resulting shaft seal limiting structure 4033 is used to form an axial limit of the shaft seal 403 with the shaft seal positioning shoulder 405 of the high-speed rotor 4.

[0036] A rotary shaft seal guide surface 4035 is provided on the outer side of the shaft seal bearing surface 4034. The meridian of the shaft seal guide surface 4035 is parallel to the meridian of the thrust guide surface 513 and forms a guide gap 514. The axial dimension of the guide gap 514 is controlled within (0.3-0.5) mm.

[0037] The outer diameter of the shaft seal guide surface 4036 is smaller than that of the thrust guide surface 513, and a pressure-side oil unloading gap 515 is formed between the two. The minimum size of the pressure-side oil unloading gap 515 is controlled within (0.2-0.25) mm.

[0038] The locking nut 404 locks the shaft seal 403 and the impeller 102 together onto the high-speed rotor 4. The locking direction of the impeller 102 is consistent with the direction of the aerodynamic torque that the impeller 102 experiences during normal operation. A nose limiting structure 1023 is provided on the impeller nose 1022 of the impeller 102. The locking nut 404 is a hexagonal head nut; the groove depth between the nose limiting structures 1023 is (1-5) mm, and the groove width is less than the pitch circle diameter of the locking nut 404 and greater than the inscribed circle diameter, to prevent the impeller 102 from rotating due to insufficient locking torque.

[0039] The axial distance between the thrust sleeve bearing surface 4023 and the shaft seal bearing surface 4034 is (0.05-0.10) mm larger than the axial distance between the pressure side bearing surface 501 and the vortex side bearing surface 502.

[0040] Based on the parallel disk theoretical model, the approximate formula (1) for calculating the bearing capacity of a double-sided circulating thrust bearing is as follows: ; In the formula This is the pressure distribution coefficient (which depends on the specific structure of the oil wedge). For oil supply pressure, The outer diameter of the thrust surface on the pressure side is 504 or the outer diameter of the thrust surface on the vortex side is 505. The inner diameter of the thrust surface is 503. To push the outer radius of the surface, The inner radius of the thrust surface.

[0041] For frictional power consumption, it mainly comes from the frictional force formed by oil film shearing. The formula (2) for calculating the differential frictional torque on the annular micro-element thrust surface is: ; In the formula, shear force linear velocity .

[0042] Integrating over the annular area, the formula for calculating frictional power consumption (3) is: ; In the formula, The dynamic viscosity of the lubricating oil. Angular velocity, This refers to the oil film thickness.

[0043] From formula (1), it can be seen that when When decreasing, through Reduce, can Unchanged. As can be seen from formula (3), while maintaining the bearing capacity... Under the premise of remaining unchanged, with and The reduction of [value] can achieve [the desired result]. Without changing, This reduces the size of the turbocharger shaft system, thereby improving its mechanical efficiency.

[0044] The working principle of this device is as follows: The thrust sleeve 402 is fastened to the high-speed rotor 4 using the internal thread 4021 and the thrust sleeve limiting structure 4026. Through the shaft seal limiting structure 4033 of the shaft seal 403, the shaft seal 403 and the impeller 102 can be locked together on the high-speed rotor 4 by the locking nut 404. This achieves independent axial positioning of the thrust sleeve 402 and the shaft seal 403, thereby eliminating the pressing part of the traditional thrust sleeve and the traditional shaft seal in the traditional turbocharger shaft system structure. That is, it eliminates the dimension of the shaft seal connection thickness l in the superposition relationship of the three dimensions "rotor radius r + shaft seal connection thickness l + thrust inner clearance s" that the inner radius of the existing thrust bearing 5 needs to meet. This achieves the purpose of reducing the inner diameter of the thrust bearing 5 in terms of structure. At the same time, by setting an axial oil drain groove 506 on the thrust bearing 5, a portion of the oil thrown out from the pressure side bearing surface 501 enters the vortex side oil drain channel 709, thereby reducing the amount of oil entering the negative pressure assembly 3, and thus improving the turbocharger's anti-negative pressure oil leakage characteristics. At the same time, through the guide gap 514 formed by the shaft seal guide surface 4035 and the thrust guide surface 513, and the axial oil discharge groove 506 provided on the thrust bearing 5, the oil thrown out from the pressure side bearing surface 501 is guided to the axial oil discharge groove 506, and most of the oil then enters the outer oil discharge groove 705 and the vortex side oil discharge channel 709 through the axial oil discharge groove 506. To prevent the clamping surface between the shaft seal limiting structure 4033 and the shaft seal positioning shoulder 405 from being too narrow, which would result in insufficient locking torque for the impeller 102 during operation, a nose limiting structure 1023 is provided on the impeller nose 1022. When the locking torque of the locking nut 404 is insufficient, the impeller 102 can be stuck by the groove structure to prevent it from slipping and failing. This invention can significantly reduce the inner radius of the thrust surface while maintaining the load-bearing capacity of the turbocharger thrust bearing 5, thereby greatly improving the friction power consumption of the thrust bearing 5; and can divert the oil thrown out by the pressure side thrust surface to the vortex side of the thrust surface, reducing the oil flow into the negative pressure component 3, thereby improving the turbocharger's resistance to negative pressure oil leakage. The present invention features a clever and compact structural design. Without significantly increasing manufacturing costs and complexity, it achieves excellent low power consumption and high resistance to negative pressure through a series of mutually cooperating geometric configuration optimizations. It is particularly suitable for high power density engines with extremely high requirements for efficiency and negative pressure oil leakage resistance, and has significant engineering application value and promotion prospects.

[0045] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be covered within the scope of the claims and specification of the present invention.

Claims

1. A turbocharger based on a shaft system structure with high negative pressure resistance, comprising a bearing housing (7), a high-speed rotor (4), a thrust sleeve (402), a thrust bearing (5), a shaft seal (403), and an impeller (102). The high-speed rotor (4) is disposed within the bearing housing (7), and the impeller (102), shaft seal (403), thrust bearing (5), and thrust sleeve (402) are sequentially and axially arranged side by side on the high-speed rotor (4); characterized in that: The thrust sleeve (402) is independently fixed to the high-speed rotor (4) through an axial positioning structure; the impeller (102) and the shaft seal (403) are independently fixed to the high-speed rotor (4) through an axial positioning structure; the inner diameter (503) of the thrust surface of the thrust bearing (5) and the high-speed rotor (4) are provided with a thrust bearing inner clearance (407).

2. The turbocharger based on high negative pressure resistance capability shafting structure according to claim 1, characterized in that: The thrust bearing (5) has a pressure side bearing surface (501) and a vortex side bearing surface (502) connected to the inner gap (407) of the thrust bearing on both sides. The thrust bearing (5) has an axial oil discharge groove (506) that guides the oil on the pressure side bearing surface (501) to the vortex side oil discharge channel (709).

3. The turbocharger based on a shaft system structure with high negative pressure resistance according to claim 1, characterized in that: The thrust bearing (5) is provided with a thrust bearing oil supply hole (509), and the outlet end of the thrust bearing oil supply hole (509) is connected to the inner clearance (407) of the thrust bearing.

4. The turbocharger based on a shaft system structure with high negative pressure resistance according to claim 2, characterized in that: The pressure side bearing surface (501) and the vortex side bearing surface (502) are provided with a number of fan-shaped oil wedges (511) in the circumferential direction. A radial oil supply groove (512) is provided between adjacent fan-shaped oil wedges (511), and the radial oil supply groove (512) is connected to the inner clearance (407) of the thrust bearing.

5. The turbocharger based on a shaft system structure with high negative pressure resistance according to claim 1, characterized in that: The axial positioning structure includes an external thread (4013) that mates with the high-speed rotor (4) and the thrust sleeve (402).

6. The turbocharger based on a shaft system structure with high negative pressure resistance according to claim 1, characterized in that: The axial positioning structure includes a thrust sleeve positioning shoulder (406) located on the high-speed rotor (4), and one end of the thrust sleeve (402) is provided with a thrust sleeve limiting structure (4026) that abuts against the thrust sleeve positioning shoulder (406).

7. The turbocharger based on a shaft system structure with high negative pressure resistance according to claim 1, characterized in that: The second axial positioning structure includes a shaft seal positioning shoulder (405) located on the high-speed rotor (4), and the inner hole of the shaft seal (403) is provided with a shaft seal limiting structure (4033) that abuts against the shaft seal positioning shoulder (405).

8. The turbocharger based on a shaft system structure with high negative pressure resistance according to claim 1, characterized in that: The second axial positioning structure includes a locking nut (404) threaded to the end of the high-speed rotor (4). The locking nut (404) abuts against the impeller nose (1022) of the impeller (102). The impeller nose (1022) is provided with a nose limiting structure (1023) that limits the locking nut (404).

9. The turbocharger based on a shaft system structure with high negative pressure resistance according to claim 8, characterized in that: The nose limiting structure (1023) includes a positioning groove formed on the end of the impeller nose (1022), one of the opposite sidewalls of the positioning groove penetrates the impeller nose (1022), and the groove width of the other opposite inner wall of the positioning groove is smaller than the pitch circle diameter of the locking nut (404) and larger than the inscribed circle diameter of the locking nut (404).

10. The turbocharger based on a shaft system structure with high negative pressure resistance according to claim 2, characterized in that: The pressure-side bearing surface (501) is provided with a thrust guide surface (513) in a U-shape, and the shaft seal bearing surface (4034) is provided with a shaft seal guide surface (4035) in a U-shape. The meridian of the shaft seal guide surface (4035) is parallel to the meridian of the thrust guide surface (513) and forms a guide gap (514). The outer diameter (4036) of the shaft seal guide surface is smaller than the outer diameter of the thrust guide surface (513) and forms a pressure-side unloading gap (515). The pressure-side unloading gap (515), the guide gap (514), and the axial unloading groove (506) are connected to each other.

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