A sealing structure for the compressor end of a turbocharger and a turbocharger

Abstract

This utility model relates to the field of turbocharger technology, specifically a sealing structure for the compressor end of a turbocharger and a turbocharger. It includes a thrust bearing, an oil baffle plate, and a sealing sleeve. The oil baffle plate, near the thrust bearing, has an arc-shaped guide surface for directing splashed lubricating oil to the oil return channel at the bottom of the thrust bearing, and a drainage portion bent towards the thrust bearing. The oil baffle plate, near the sealing sleeve, has at least two axial annular bosses spaced apart. The sealing sleeve, near the oil baffle plate, has an axial annular groove that fits with the axial annular bosses with a clearance fit, forming a labyrinthine gap. A gas seal cover is fitted on the side of the sealing sleeve away from the oil baffle plate. The inner diameter of the gas seal cover has a sealing ring that fits between it and the sealing sleeve. The outer circumference of the sealing sleeve has a radial annular groove that seals with the sealing ring. This utility model can meet the requirement of no oil leakage under an intake negative pressure of -14 kPa at engine idling conditions.

Description

Technical Field

[0001] This utility model relates to the field of turbocharger technology, specifically to a sealing structure for the compressor end of a turbocharger and a turbocharger. Background Technology

[0002] During the operation of a turbocharger, a negative pressure phenomenon is generated at the compressor end due to the suction effect. This negative pressure often causes engine oil to leak from the bearing housing and be drawn into the compressor. This not only increases oil consumption but also contaminates the intake system. More seriously, this leakage can even affect engine performance and emission standards. While existing labyrinth seal structures can prevent oil leakage to some extent, their resistance to negative pressure is relatively limited. Therefore, under certain operating conditions, such as engine idling, existing labyrinth seal structures often struggle to meet high negative pressure requirements, such as -14 kPa or even lower. In these cases, the existing labyrinth seal structure is not ideal in preventing oil leakage to the compressor end. Therefore, for negative pressure values ​​of -14 kPa or even lower, there is an urgent need to develop a new structural design. This design should not only effectively intercept lubricating oil leaking from the bearing housing through an oil baffle but also utilize the throttling principle of the labyrinth gaps to significantly improve the compressor end's resistance to negative pressure. This effectively reduces oil leakage, lowers pollution to the intake system, and thus improves the overall performance and emissions of the engine. Utility Model Content

[0003] The problem to be solved is to provide a sealing structure for preventing oil leakage to the compressor end of a turbocharger. Through the coordinated design of the labyrinthine gap between the oil baffle and the sealing sleeve 3, the lubricating oil of the bearing body is effectively blocked, and the negative pressure resistance of the compressor end is improved by 4-6 kPa, which meets the negative pressure requirements of -14 kPa and lower under engine idling conditions.

[0004] To achieve the above objectives, this utility model provides the following technical solution: a sealing structure for the compressor end of a turbocharger, comprising a thrust bearing, an oil baffle plate disposed between the thrust bearing and the compressor, and a sealing sleeve sleeved on the outside of the oil baffle plate; the oil baffle plate is provided with an arc-shaped guide surface for guiding lubricating oil to the oil return channel at the bottom of the thrust bearing and a drainage part bent towards the thrust bearing side on the side near the thrust bearing; the oil baffle plate is provided with at least two axial annular bosses spaced apart on the side near the sealing sleeve, and the sealing sleeve is provided with an axial annular groove that is clearance-fitted with the axial annular bosses on the side near the oil baffle plate, the axial annular groove and the axial annular bosses forming a labyrinth-like gap; a gas seal cover is sleeved on the side of the sealing sleeve away from the oil baffle plate, the inner diameter of the gas seal cover is provided with a sealing ring between it and the sealing sleeve, and the outer circumference of the sealing sleeve is provided with a radial annular groove that seals with the sealing ring.

[0005] Preferably, the width of each level of the multi-level labyrinthine gap is 0.1 to 0.3 mm, the length is 1 to 2 mm, and the spacing between adjacent axial annular bosses is 5 to 8 times the width of the labyrinthine gap.

[0006] Preferably, the axial annular boss of the oil baffle adopts a trapezoidal or sawtooth asymmetrical tooth structure, with the tooth tip width being smaller than the tooth root width.

[0007] Preferably, there are two axial annular bosses and two axial annular grooves, with the axial annular bosses and axial annular grooves being staggered.

[0008] Preferably, the oil baffle and the sealing sleeve are connected by bolts after a clearance fit.

[0009] Preferably, the thrust bearing includes a turbine end thrust plate and a press end thrust plate, with the arc-shaped guide surface located outside the turbine end thrust plate.

[0010] Preferably, the axial clearance between the axial annular boss and the axial annular groove is 0.15 to 0.35 mm.

[0011] A turbocharger comprising the compressor end sealing structure described above.

[0012] Compared with existing technologies, this utility model provides a sealing structure for the compressor end of a turbocharger and a turbocharger, which has the following beneficial effects: The oil baffle plate is designed with an arc-shaped guide surface near the bearing housing, utilizing fluid dynamics principles to guide splashed lubricating oil along the curved surface to the oil return channel. Compared with traditional flat oil baffle plates, the oil-blocking efficiency is improved by more than 30%, reducing the diffusion of engine oil to the compressor end from the source. The axial annular boss of the oil baffle plate and the axial annular groove of the sealing sleeve form a labyrinth-like gap structure, reducing the diffusion of lubricating oil to the compressor end and achieving efficient oil blocking. The multi-stage labyrinth-like gap design significantly weakens the suction effect of the compressor negative pressure on the engine oil using the throttling principle. Compared with traditional structures, the compressor end's negative pressure resistance is improved by 4-6 kPa, meeting the requirement of no oil leakage at the compressor end under an intake negative pressure of -14 kPa at engine idling conditions. The combined structure of the sealing sleeve and the oil baffle plate is fixedly connected by bolts, making installation convenient and space-saving, and suitable for different models of turbochargers. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of the installation of the sealing structure of this utility model;

[0014] Figure 2 This utility model Figure 1 A cross-sectional schematic diagram;

[0015] Figure 3 This is a schematic diagram of the explosion of the sealing sleeve and oil baffle plate on the press side of this utility model;

[0016] Figure 4 This is a schematic diagram of the explosion of the sealing sleeve and oil baffle plate on the turbine side of this utility model;

[0017] Figure 5 This is a schematic cross-sectional view of the sealing sleeve and oil baffle plate after installation of this utility model;

[0018] Figure 6 This is a schematic diagram of an embodiment of the present utility model;

[0019] Figure 7 This utility model Figure 6 Enlarged view of point A;

[0020] Explanation of reference numerals in the attached drawings: 1. Thrust bearing; 11. Turbine end thrust plate; 12. Press end thrust plate; 2. Oil baffle; 21. Axial annular boss; 22. Drainage section; 23. Arc-shaped guide surface; 3. Sealing sleeve; 31. Axial annular groove; 32. Radial annular groove; 4. Gas seal cover; 41. Gas seal cover retaining ring; 43. Gas seal cover sealing ring; 42. Sealing ring; 5. Labyrinth gap; 6. Floating bearing; 61. Floating bearing retaining ring; 7. Turbine end; 71. Turbine rotor; 72. Vortex end sealing ring; 73. Heat insulation cover; 8. Intermediate body; 81. Limiting sleeve; 82. Intermediate body sealing ring; 9. Press end; 91. Impeller; 10. Rotor shaft. Detailed Implementation

[0021] The technical solutions of the present utility model will now be described with reference to the accompanying drawings in the embodiments of the present utility model:

[0022] The system includes a thrust bearing 1, an oil baffle 2, a sealing sleeve 3, and an air seal cover 4. The oil baffle 2 is located between the thrust bearing 1 and the compressor, and the sealing sleeve 3 is located on the compressor side and sleeved on the outside of the oil baffle 2. The thrust bearing 1 bears the bidirectional thrust of the rotor shaft 10. The side of the oil baffle 2 near the thrust bearing 1 is provided with an arc-shaped guide surface 23. The arc-shaped guide surface 23 is used to guide the splashed lubricating oil to the oil return channel at the bottom of the thrust bearing 1. The thrust bearing 1 includes a turbine end thrust plate 11 and a compressor end thrust plate 12. The arc-shaped guide surface 23 is located outside the turbine end thrust plate 11. The arc-shaped guide surface 23 utilizes the principle of fluid dynamics to guide the splashed lubricating oil along the tangential direction of the curved surface to the oil return channel to reduce oil splashing and rebound. Below the oil baffle 2, there is a drainage portion 22 bent towards the thrust bearing 1; the edge of the oil baffle 2 near the sealing sleeve 3 is provided with an axial annular boss 21, there are not less than two axial annular bosses 21 and they are spaced apart, preferably two axial annular bosses 21; the sealing sleeve 3 near the oil baffle 2 is provided with an axial annular groove 31, the axial annular groove 31 and the axial annular boss 21 are clearance-fitted to form a barrier to prevent residual oil that has not been guided from penetrating, the oil baffle 2 and the sealing sleeve 3 are connected by bolts after clearance fit. The axial annular boss 21 of the oil baffle 2 adopts a trapezoidal or sawtooth asymmetrical tooth structure, the tooth tip width is smaller than the tooth root width. At least two axial annular grooves 31 and at least two axial annular bosses 21 are fitted together to form a multi-level labyrinthine gap 5. Each level of the multi-level labyrinthine gap 5 has a gap width of 0.1–0.3 mm and a length of 1–2 mm. The spacing between adjacent axial annular bosses 21 is 5–8 times the width of the labyrinthine gap 5. The axial clearance between the axial annular bosses 21 and the axial annular grooves 31 is 0.15–0.35 mm. An air seal cover 4 is fitted on the side of the sealing sleeve 3 away from the oil baffle 2. The air seal cover 4 and the sealing sleeve 3 are sealed together by a sealing ring 42. The outer circumference of the sealing sleeve 3 is provided with a radial annular groove 32, which is sealed together with the sealing ring 42.

[0023] The sealing structure of this utility model is applied to a certain type of turbocharger. Since the turbocharger structure is existing technology, such as... Figure 6 , Figure 7 The turbocharger shown includes a turbine end 7, which includes a turbine rotor 71. The turbine end 7 is sealed to an intermediate body 8 via a turbine end sealing ring 72. A heat shield 73 is disposed between the turbine end 7 and the intermediate body 8. A floating bearing 6 is sleeved on the rotor shaft 10, and a floating bearing retaining ring 61 is provided on the side of the floating bearing 6 near the turbine end 7. A limiting sleeve 81 is provided between the intermediate body 8 and the floating bearing 6. The other side of the intermediate body 8 is sealed to the compressor end 9 via an intermediate body sealing ring 82. The compressor end 9 includes an impeller 91, and an air seal cover 4 is sealed to the compressor end 9 via an air seal cover retaining ring 41. The air seal cover 4 is sealed to the intermediate body 8 via an air seal cover sealing ring 43. Figure 7 The thrust bearing 1, oil baffle 2, and sealing sleeve 3 of this utility model are arranged between the intermediate body 8 and the rotor shaft 10. The oil baffle 2 is located between the thrust bearing 1 and the press end 9. An arc-shaped guide surface 23 is provided on the side of the oil baffle 2 near the thrust bearing 1, which can guide the lubricating oil splashed from the thrust bearing 1 to the oil return channel at the bottom of the thrust bearing 1, thus achieving initial blocking of the lubricating oil. An axial annular boss 21 is provided on the edge of the oil baffle 2 near the press end 9. The axial annular boss 21 fits tightly with the inner wall of the sealing sleeve 3 to form the first sealing barrier. The sealing sleeve 3 is sleeved on the outside of the oil baffle 2. A multi-level labyrinthine gap 5 is provided between the inner wall of the sealing sleeve 3 and the outer wall of the oil baffle 2. The labyrinthine gap 5 is formed by the axial annular groove 3 on the inner wall of the sealing sleeve 3. The axial annular protrusions 21 on the outer wall of the oil baffle 2 are interwoven, and the width of each labyrinth gap 5 is b, which is 0.1 to 0.3 mm, and the length is a, which is 1 to 2 mm. The distance between adjacent axial annular protrusions 21 is c, which is 5 to 8 times the width b of the labyrinth gap 5. The axial clearance between the oil baffle 2 and the plane of the sealing sleeve 3 is d, which is 0.15 to 0.35 mm. The clearance between the oil baffle 2 and the plane of the compressor end thrust plate 12 is n, which is 0.1 to 0.3 mm. When the compressor generates negative pressure, the oil flows through the labyrinth gap 5. Through multi-stage throttling and pressure reduction and viscous resistance, energy is consumed, reducing the suction effect of negative pressure on the oil. The oil baffle 2 and the sealing sleeve 3 are fixedly connected by bolts to form a stable oil leakage prevention structure.

[0024] During installation, first install the oil baffle 2 between the thrust bearing 1 and the compressor, so that the arc-shaped guide surface 23 of the oil baffle 2 faces the thrust bearing 1, ensuring that the lubricating oil splashed from the thrust bearing 1 can flow into the oil return channel at the bottom of the thrust bearing 1 along the guide surface; then, put the sealing sleeve 3 on the outside of the oil baffle 2, so that the axial annular groove 31 on the inner wall of the sealing sleeve 3 and the axial annular boss 21 on the outer wall of the oil baffle 2 are misfitted to form a multi-level labyrinth gap 5; then, fix the oil baffle, sealing sleeve 3 and oil baffle 2 together with bolts to ensure the sealing performance between the components; finally, test the assembled turbocharger. When the compressor end negative pressure reaches -14kPa under engine idling conditions, check whether there is oil leakage from the compressor outlet.

[0025] The multi-stage labyrinthine slit 5 employs a staggered structure of multi-stage axial annular grooves 31 and axial annular protrusions 21 (each slit width is 0.1–0.3 mm, and length is 1–2 mm). It utilizes the throttling effect of fluid passing through the narrow slits to progressively dissipate the suction energy generated by the compressor's negative pressure. By optimizing the ratio of the axial annular protrusions 21 to the slit width (5–8 times), turbulence and viscous resistance are created within the slits. Compared to traditional equidistant labyrinth structures, the throttling and pressure reduction efficiency is increased by 40%, and the resistance to negative pressure is significantly enhanced.

[0026] The axial annular boss 21 on the outer wall of the oil baffle adopts a trapezoidal or sawtooth asymmetrical design (e.g., narrow tooth tip, wide tooth root), which generates abrupt change in flow resistance when the fluid passes through, further enhancing energy loss. Combined with the axial annular groove 31 structure of the sealing sleeve 3, it forms a "contraction-expansion" throttling channel, maximizing the negative pressure attenuation effect. The radius of curvature of the arc-shaped guide surface 23 and the number of labyrinth gaps are optimized according to the negative pressure fluctuation characteristics of different engine operating conditions (idle, high speed, variable load). For example, at high negative pressure during idling, the throttling effect of the multi-stage gaps can stably maintain the anti-negative pressure capability, while at high speed, the guide surface can effectively cope with the increase in lubricating oil splash, ensuring leak-proof performance under all operating conditions. The labyrinth gap width (0.1-0.3mm) is controlled with micron-level precision through CNC turning or EDM, ensuring the consistency of each gap size and avoiding attenuation of the throttling effect due to machining errors. Compared with traditional stamping processes, the gap precision is improved by 50%. The oil baffle 2 and sealing sleeve 3 can be quickly assembled by positioning pins and bolts, ensuring the alignment accuracy of the labyrinth gap without complicated adjustments, reducing assembly time by 30%, making it suitable for mass production, and also facilitating later maintenance and replacement.

[0027] A comparison of the structure of this utility model with that of the traditional sealing structure is shown in Table 1 below:

[0028] Table 1:

[0029]

[0030] Through the aforementioned innovations, this utility model achieves a technological upgrade from "passive blocking" to "active throttling and pressure reduction," solving the engineering problem of oil leakage at the compressor end of the turbocharger and providing a new solution for the field of high negative pressure sealing. The actual leak-proof performance of the sealing structure of this utility model under different operating conditions was verified to confirm whether it meets the -14kPa negative pressure requirement under engine idling conditions. The verification method is as follows:

[0031] (1) Turbocharger test bench: equipped with an adjustable speed motor, a negative pressure regulation system (which can simulate negative pressure from -20kPa to 0kPa), and a lubricating oil circulation system (which can control the oil temperature from 80 to 120℃).

[0032] (2) Data acquisition system: pressure sensor (accuracy ±0.01kPa) for monitoring the negative pressure at the compressor end and the pressure before and after each gap; flow meter (accuracy ±0.5%) for measuring the amount of oil leakage; infrared thermometer for monitoring the temperature of key components; transparent tube.

[0033] (3) Select a turbocharger of the same model with a traditional sealing structure as a comparison benchmark.

[0034] (4) Install the sealing structure of this application and the original turbocharger structure onto a dedicated turbocharger test bench to ensure that there is no leakage. Set the oil temperature of the lubricating oil circulation system to 100°C to simulate the normal operating temperature of the engine.

[0035] (5) Idle condition test: Adjust the negative pressure system to -14kPa to simulate the negative pressure at the compressor end when the engine is idling. Run continuously for 30 minutes, and observe the transparent air outlet pipe of the compressor every 5 minutes to see if there is any oil leakage. At the same time, record the amount of oil leakage, the pressure before and after each gap, the system temperature and other data.

[0036] (6) Variable load test: The negative pressure is gradually adjusted from -8kPa to -14kPa with a gradient of 2kPa. Each negative pressure value is run stably for 30 minutes, and the corresponding data is recorded.

[0037] (7) High temperature test: Maintain negative pressure -14kPa, raise oil temperature to 120℃, run for 30 minutes, and monitor oil leakage and structural stability.

[0038] (8) Record the oil leakage of the present invention structure and the comparative sample under different working conditions. The results are shown in Table 2 below.

[0039] Table 2:

[0040]

[0041]

[0042] In summary, this invention, through the synergistic design of the arc-shaped guide surface 23 and the multi-stage labyrinth gap 5, significantly improves the negative pressure resistance of the turbocharger compressor end, meeting the engine's idle speed requirement of -14 kPa. Compared to traditional structures, this invention exhibits significant advantages in oil leakage, pressure decay rate, and high-temperature stability, demonstrating both practicality and innovation.

[0043] The above embodiments are merely some, not all, of the embodiments of this utility model. All other embodiments obtained by those skilled in the art based on the embodiments of this utility model without inventive effort are within the scope of protection of this utility model.

Claims

1. A seal structure for a turbocharger compressor end, characterized by: The components include a thrust bearing (1), an oil baffle plate (2) disposed between the thrust bearing (1) and the compressor, and a sealing sleeve (3) fitted on the outside of the oil baffle plate (2); the oil baffle plate (2) near the thrust bearing (1) is provided with an arc-shaped guide surface (23) for guiding lubricating oil to the bottom oil return channel of the thrust bearing (1) and a drainage part (22) bent toward the thrust bearing (1); the oil baffle plate (2) near the sealing sleeve (3) is provided with at least two axial annular bosses (21) spaced apart, and the sealing sleeve (3) On the side near the oil baffle (2), there is an axial annular groove (31) that is in clearance fit with the axial annular boss (21). The axial annular groove (31) and the axial annular boss (21) form a labyrinth-like gap (5). On the side of the sealing sleeve (3) away from the oil baffle (2), there is an air seal cover (4). The inner diameter of the air seal cover (4) is provided with a sealing ring (42) between it and the sealing sleeve (3). The outer periphery of the sealing sleeve (3) is provided with a radial annular groove (32) that is in seal fit with the sealing ring (42).

2. The sealing structure for the compressor end of a turbocharger according to claim 1, characterized in that: The width of each level of the multi-level labyrinthine gap (5) is 0.1~0.3mm, the length is 1~2mm, and the spacing between adjacent axial annular bosses (21) is 5~8 times the width of the labyrinthine gap (5).

3. The sealing structure for the compressor end of a turbocharger according to claim 1, characterized in that: The axial annular boss (21) of the oil baffle (2) adopts a trapezoidal or sawtooth asymmetrical tooth structure, and the tooth tip width is smaller than the tooth root width.

4. The sealing structure for the compressor end of a turbocharger according to claim 2 or 3, characterized in that: The number of axial annular bosses (21) is two, the number of axial annular grooves (31) is two, and the axial annular bosses (21) and axial annular grooves (31) are staggered.

5. The sealing structure for the compressor end of a turbocharger according to claim 1, characterized in that: The oil baffle (2) and the sealing sleeve (3) are connected by bolts after clearance fit.

6. The sealing structure for the compressor end of a turbocharger according to claim 1, characterized in that: The thrust bearing (1) includes a turbine end thrust plate (11) and a press end thrust plate (12), with an arc-shaped guide surface (23) located outside the turbine end thrust plate (11).

7. The sealing structure for the compressor end of a turbocharger according to claim 1, characterized in that: The axial gap between the axial annular boss (21) and the axial annular groove (31) is 0.15~0.35mm.

8. A turbocharger, characterized in that: It includes the compressor end sealing structure as described in any one of claims 1–7.

Images