An end seal structure of a turbocharger

Abstract

The present invention relates to a turbocharger shaft end sealing structure, comprising a turbocharger housing, a turbine shaft rotatably mounted within the turbocharger housing, a shaft sleeve and an impeller fixedly sleeved on the outer circumference of the turbine shaft from the inside out, an oil baffle and an end cover provided on the outer circumference of the shaft sleeve, and the oil baffle and the end cover fixed in the turbocharger housing in the axial direction from the inside out. The present invention has a simple structure and occupies a small space; an internal annular groove located between two sealing rings is used to effectively block the flow of lubricating oil in the fitting gap; an oil drain hole at the bottom of the internal annular groove is used to guide the intercepted lubricating oil back to the inner cavity of the turbocharger; the shaft end sealing structure has good sealing performance under extreme working conditions; the shaft end sealing structure is compact and interchangeable with traditional shaft end sealing structures.

Description

Technical Field

[0001] The invention belongs to the technical field of turbochargers and relates to a shaft end sealing structure of a turbocharger. Background Art

[0002] A turbocharger utilizes the energy of an internal combustion engine's exhaust gas to compress the air it receives, significantly increasing intake pressure, density, and quality. This significantly increases the engine's power and torque, while reducing fuel consumption and harmful pollutant emissions. During operation, the turbine shaft of a turbocharger drives the impeller at high speed, necessitating a shaft end seal at the axial bore of the turbocharger housing. Traditional shaft end seals feature a sealing ring groove and an elastic sealing ring with an opening between the turbine shaft and the axial bore. When lubricating oil leaks through the mating clearance, it is blocked by the sealing ring, increasing flow resistance and reducing leakage. Existing structural improvements typically incorporate a seal at the end of the axial bore to block or divert the lubricating oil, reducing the amount entering the mating clearance. However, under extreme operating conditions, such as negative intake pressure, the internal pressure of the turbocharger is slightly higher than the external pressure, and lubricating oil inevitably leaks through the mating clearance. Summary of the Invention

[0003] The purpose of the present invention is to provide a turbocharger shaft end sealing structure that can solve the problem that under extreme working conditions such as intake negative pressure, the internal air pressure of the turbocharger is slightly higher than the external air pressure, and the lubricating oil will inevitably leak to the outside of the turbocharger through the fitting gap.

[0004] According to the technical solution provided by the present invention: a shaft end sealing structure of a turbocharger includes a turbocharger housing, a turbine shaft is rotatably installed inside the turbocharger housing, a shaft sleeve and an impeller are fixedly sleeved on the outer periphery of the turbine shaft from the inside to the outside along the axial direction, an oil baffle and an end cover are provided on the outer periphery of the shaft sleeve and are clearance-matched, a thrust bearing, an oil baffle and an end cover are fixed in the turbocharger housing in sequence along the axial direction from the inside to the outside, an oil inlet hole is opened on the turbocharger housing, an oil guide hole is opened in the thrust bearing to connect the upper end surface and the inner periphery, and an oil inlet hole is provided. The end outlet faces the upper part of the thrust bearing end surface and is connected to the oil guide hole. The lower inclined plate of the oil baffle is located below the thrust bearing and points to the oil return hole at the bottom of the turbocharger housing. It is characterized in that there is an annular groove inside the end cover, which divides the end cover into an end cover near bearing section and an end cover far bearing section. An oil drain hole is opened at the lower part of the end cover, and the two ends of the oil drain hole are respectively connected to the annular groove and the turbocharger housing; two sealing ring grooves are respectively opened on the inner circumference of the shaft sleeve corresponding to the end cover near bearing section and the end cover far bearing section, and a seal is installed in each sealing ring groove.

[0005] As a further improvement of the present invention, the thrust bearing, the oil baffle plate and the end cover are fixed in sequence in the turbocharger housing from the inside to the outside along the axial direction using retaining rings.

[0006] As a further improvement of the present invention, the sealing member is an elastic metal sealing ring with an opening.

[0007] As a further improvement of the present invention, an oil-swinging groove is provided between the two sealing ring grooves of the shaft sleeve.

[0008] As a further improvement of the present invention, the diameter of the inner circumference of the distal bearing section of the end cover is smaller than the diameter of the inner circumference of the proximal bearing section of the end cover.

[0009] As a further improvement of the present invention, a proximal inverted conical boss and a distal inverted conical boss are respectively provided on the inner circumferential end surfaces of the end cover proximal bearing section and the end cover distal bearing section facing the thrust bearing.

[0010] As a further improvement of the present invention, the inner peripheries of the end cover proximal bearing section and the end cover distal bearing section facing the thrust bearing are provided with tapered chamfers, and the shaft sleeve is provided with a tapered shaft section.

[0011] As a further improvement of the present invention, the end cover proximal bearing section and the end cover distal bearing section can be made into an integral body or can be assembled after being separated.

[0012] As a further improvement of the present invention, the inner periphery of the thrust bearing is clamped between the inner end surface of the sleeve and the stop of the turbine shaft and maintains radial and axial clearance fit.

[0013] The positive progress of this application is:

[0014] The present invention has a simple structure and occupies a small space; an annular groove inside the end cover between the two sealing rings is used to effectively block the flow of lubricating oil in the fitting gap; an oil drain hole at the lower part of the internal annular groove is used to guide the intercepted lubricating oil back to the inner cavity of the turbocharger housing; the shaft end sealing structure has good sealing performance under extreme working conditions; the shaft end sealing structure is compact and can be interchanged with traditional shaft end sealing structures. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a structural schematic diagram of the present invention.

[0016] Figure 2 for Figure 1 Schematic diagram of the enlarged region I in the middle. DETAILED DESCRIPTION

[0017] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments of the present invention may be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0018] In order to enable those skilled in the art to better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of the present invention.

[0019] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the numbers used in this way can be interchanged where appropriate for the embodiments of the present invention described herein. In addition, similar terms such as "including" and "having" mean that in addition to those contents already listed in "including" and "having", other contents that have not been listed may also be "included" and "having"; for example, a process, method, system, product or device that may include a series of steps or units is not necessarily limited to those steps or units that have been clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0020] Figures 1-2 The turbocharger assembly includes a turbocharger housing 1, an end cover 2, a sleeve 5, a turbine shaft 6, an impeller 7, an oil baffle 9, a thrust bearing 11, a seal 16, etc.

[0021] like Figures 1-2 As shown, the present invention is a shaft end sealing structure of a turbocharger, comprising a turbocharger housing 1, wherein a turbine shaft 6 is rotatably mounted inside the turbocharger housing 1, a shaft sleeve 5 and an impeller 7 are fixedly sleeved on the outer periphery of the turbine shaft 6 in sequence from the inside to the outside along the axial direction, an oil baffle 9 and an end cover 2 are provided on the outer periphery of the shaft sleeve 5 and are clearance-fitted, a thrust bearing 11, the oil baffle 9 and the end cover 2 are fixed in sequence in the turbocharger housing 1 in the axial direction from the inside to the outside, the inner periphery of the thrust bearing 11 is clamped between the inner end face of the shaft sleeve 5 and the stop 6-1 of the turbine shaft 6 and maintains radial and axial clearance fit, and the turbocharger housing 1 is opened. There is an oil inlet hole 1-1, and an oil guide hole 11-1 is opened in the thrust bearing 11 to connect the upper end surface and the inner periphery. The inner end outlet of the oil inlet hole 1-1 faces the upper end surface of the thrust bearing 11 and is connected to the oil guide hole 11-1. The lower inclined plate 9-1 of the oil baffle plate 9 is located below the thrust bearing 11 and points to the oil return hole at the bottom of the turbocharger housing 1. There is an annular groove 2-2 inside the end cover 2, and the annular groove 2-2 divides the end cover 2 into the end cover near bearing section 2-3 and the end cover far bearing section 2-4. An oil drain hole 8 is opened at the lower part of the end cover 2, and the two ends of the oil drain hole 8 are respectively connected to the annular groove 2-2 and the turbocharger housing 1.

[0022] Two sealing ring grooves 5-1 are respectively formed on the inner circumference of the shaft sleeve 5 corresponding to the end cover near bearing section 2-3 and the end cover far bearing section 2-4, and a sealing member 16 is installed in each sealing ring groove 5-1.

[0023] In this embodiment, the sealing member 16 is an elastic metal sealing ring with an opening.

[0024] In order to facilitate oil throwing, an oil throwing groove 5-2 is provided between the two sealing ring grooves 5-1 of the shaft sleeve 5, and the oil throwing groove 5-2 makes the cylindrical surface of the shaft sleeve 5 discontinuous.

[0025] In order to facilitate the assembly of the shaft sleeve 5 with a ring into the end cover 2, the inner diameter of the end cover's distal bearing section 2-4 is smaller than the inner diameter of the end cover's proximal bearing section 2-3, and the diameters of the corresponding shaft sections, sealing ring grooves, and seals of the shaft sleeve 5 need to be changed accordingly.

[0026] In order to prevent the oil on the inner wall of the annular groove 2-2 and the outer wall of the end cover near bearing section 2-3 from flowing into the fitting clearance between the end cover far bearing section 2-4 and the shaft sleeve 5 and between the end cover near bearing section 2-3 and the shaft sleeve 5, a near inverted conical boss 2-31 and a far inverted conical boss 2-41 are respectively provided on the end surface of the inner circumference of the end cover near bearing section 2-3 and the end cover far bearing section 2-4 facing the thrust bearing 11.

[0027] In order to facilitate the assembly of the ring-mounted sleeve 5 into the end cover 2, a tapered chamfer 2-5 is provided on the inner surface of the end cover near bearing section 2-3 and the end cover far bearing section 2-4 facing the thrust bearing 11, and the sleeve 5 has a tapered shaft section 5-3 corresponding to the tapered chamfer 2-5.

[0028] An oil return hole is provided at the bottom of the turbocharger housing 1. The lower inclined plate 9-1 of the oil baffle 9 points to the oil return hole, guiding the lubricating oil flowing out of the thrust bearing 11 and the radial bearing to the oil return hole and blocking the lubricating oil splashing to the oil drain hole 8.

[0029] The turbine shaft 6 of the turbocharger is supported by radial bearings and thrust bearings 11 inside the turbocharger housing 1. The retaining ring presses and fixes the end cover 2, oil baffle 9, and thrust bearing 11 in the turbocharger housing 1 from the outside to the inside.

[0030] The shaft sleeve 5 and the impeller 7 are sequentially sleeved on the turbine shaft 6 from the inside to the outside and tightened by the shaft end nut.

[0031] In order to reduce the contact surface pressure and avoid wear when the thrust bearing 11 is subjected to axial load, a stepped distance sleeve is installed between the sleeve 5 and the stop 6-1 of the turbine shaft 6. The inner periphery of the thrust bearing 11 is clamped between the inner end face of the sleeve 5 and the step plane of the distance sleeve and maintains radial and axial clearance fit. This method ensures a larger contact area between the end face of the thrust bearing 11 and the step plane of the distance sleeve.

[0032] Working principle: This is a shaft end sealing structure of a turbocharger. When the turbine shaft 6 and the shaft sleeve 5 rotate at high speed, after the lubricating oil flows through the thrust bearing 11, most of it is guided by the oil baffle 9 into the oil return hole at the bottom of the turbocharger housing 1 and flows away. A small part enters the gap between the end cover near the bearing section 2-3 and the shaft sleeve 5 and flows along the fitting gap, passes the first seal 16 and enters the annular groove 2-2 inside the end cover 2. The space suddenly becomes larger, the lubricating oil loses pressure and is thrown out and falls into the lower part of the annular groove 2-2, and is discharged through the oil drain hole 8. The lower inclined plate 9-1 of the oil baffle 9 not only plays a guiding role, but also 2-2 is separated from the lower part of the turbocharger housing 1, and also prevents the lubricating oil in the lower part of the turbocharger housing 1 from flowing back or splashing back into the annular groove 2-2. Even under extreme working conditions, the air pressure inside the turbocharger is slightly higher than the external air pressure, which can easily cause the lubricating oil blocked at the mouth of the fitting gap to leak through the fitting gap. However, since the annular groove 2-2 has a certain space and the leaked lubricating oil is discharged through the oil drain hole 8, there is very little lubricating oil in the annular groove 2-2 and it will not be blocked at the inner peripheral hole of the end cover far bearing section 2-4. Therefore, the lubricating oil that enters the fitting gap between the end cover far bearing section 2-4 and the shaft sleeve 5 and leaks out is even less.

[0033] It will be understood that the above embodiments are merely exemplary embodiments for illustrating the principles of the present invention, and the present invention is not limited thereto. Those skilled in the art will appreciate that various modifications and improvements can be made without departing from the spirit and substance of the present invention, and such modifications and improvements are also considered to be within the scope of protection of the present invention.

Claims

1. A turbocharger shaft end sealing structure, comprising a turbocharger housing (1), a turbine shaft (6) rotatably mounted inside the turbocharger housing (1), a shaft sleeve (5) and an impeller (7) being fixedly sleeved on the outer periphery of the turbine shaft (6) in sequence from the inside to the outside along the axial direction, an oil baffle (9) and an end cover (2) being provided on the outer periphery of the shaft sleeve (5) and being clearance-fitted, a thrust bearing (11), an oil baffle (9) and an end cover (2) being fixed to the turbocharger housing in sequence from the inside to the outside along the axial direction The turbocharger housing (1) is provided with an oil inlet hole (1-1), the thrust bearing (11) is provided with an oil guide hole (11-1) communicating with the upper end surface and the inner periphery, the inner end outlet of the oil inlet hole (1-1) faces the upper end surface of the thrust bearing (11) and is connected to the oil guide hole (11-1), the lower inclined plate (9-1) of the oil baffle (9) is located below the thrust bearing (11) and points to the oil return hole at the bottom of the turbocharger housing (1), and is characterized in that: An annular groove (2-2) is provided inside the end cover (2), and the annular groove (2-2) divides the end cover (2) into an end cover near bearing section (2-3) and an end cover far bearing section (2-4). An oil drain hole (8) is provided at the lower portion of the end cover (2), and both ends of the oil drain hole (8) are connected to the annular groove (2-2) and the turbocharger housing (1). Two sealing ring grooves (5-1) are provided on the inner circumference of the shaft sleeve (5) corresponding to the end cover near bearing section (2-3) and the end cover far bearing section (2-4), and a sealing member (16) is installed in each sealing ring groove (5-1). An oil throwing groove (5-2) is provided between the two sealing ring grooves (5-1) of the shaft sleeve (5). A near inverted cone boss (2-31) and a far inverted cone boss (2-41) are provided on the end surfaces of the inner circumference of the end cover near bearing section (2-3) and the end cover far bearing section (2-4) facing the thrust bearing (11).

2. The shaft end sealing structure of the turbocharger according to claim 1, characterized in that: The thrust bearing (11), the oil baffle (9) and the end cover (2) are fixed in sequence in the turbocharger housing (1) along the axial direction from the inside to the outside using retaining rings.

3. The turbocharger shaft end sealing structure according to claim 1, wherein: The sealing member (16) is a resilient metal sealing ring with an opening.

4. The turbocharger shaft end sealing structure according to claim 1, wherein: The diameter of the inner circumference of the end cover far bearing section (2-4) is smaller than the inner circumference of the end cover near bearing section (2-3).

5. The shaft end sealing structure of the turbocharger according to claim 1, wherein: The inner circumferences of the end cover proximal bearing section (2-3) and the end cover distal bearing section (2-4) facing the thrust bearing (11) are provided with conical chamfers (2-5), and the shaft sleeve (5) is provided with a conical shaft section (5-3).

6. The turbocharger shaft end sealing structure according to claim 1, wherein: The end cover proximal bearing section (2-3) and the end cover distal bearing section (2-4) can be made into an integral body or assembled after being separated.

7. The turbocharger shaft end sealing structure according to claim 1, wherein: The inner periphery of the thrust bearing (11) is clamped between the inner end surface of the shaft sleeve (5) and the stop (6-1) of the turbine shaft (6) and maintains radial and axial clearance fit.

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