CN115788947A - A radial double-end oil-gas end-face seal structure for a turbocharger - Google Patents

Abstract

The invention discloses a radial double-end surface oil-gas end surface sealing structure for a turbocharger, which comprises a moving ring assembly, a static ring assembly, a fixed housing and a rotating shaft, the moving ring assembly and the oil throwing ring rotate with the rotating shaft, and the static ring assembly is located at the fixed Between the casing and the moving ring assembly, the static ring assembly includes a gas side static ring and an oil-gas side static ring, a gas cavity is formed between the gas side static ring, impeller, fixed casing and the moving ring assembly, the gas side static ring, the oil-gas side The variable pressure chamber is formed between the static ring and the moving ring assembly, the oil-gas chamber is formed between the oil-gas side static ring, the oil throwing ring, the fixed shell and the moving ring assembly, and the gas-side static ring is formed between the fixed shell and the gas side static ring. Compression springs are arranged between the ring and the static ring on the oil-gas side, and the end faces of the outer diameter of the static ring on the gas side and the end faces of the inner diameter of the static ring on the oil-gas side are provided with dynamic pressure grooves uniformly distributed along the circumferential direction. Under the condition that the axial dimension of the turbocharger is limited, the present invention has both low oil leakage characteristics at low-speed operation and low blow-by gas characteristics at high-speed operation.

Description

A radial double-end oil-gas end-face seal structure for a turbocharger

technical field

The invention belongs to the technical field of rotary mechanical sealing devices, and in particular relates to a radial double-end oil-gas end-face sealing structure for a turbocharger.

Background technique

Turbocharging technology is an effective way to improve vehicle engine efficiency and save energy and reduce consumption. It uses high-temperature exhaust gas to drive the turbine, drives the coaxial compressor impeller to rotate at high speed, and sends compressed air with higher pressure and density to the engine cylinder, thereby achieving increase. The purpose of engine output power. Among them, the seal is one of the important key basic parts in the turbocharging system. It is arranged between the compressor, the turbine and the bearing cavity, and is mainly used to prevent the air at the back of the compressor or the high-temperature gas at the turbine end from entering the bearing cavity and contaminating the oil. At the same time, it also prevents the engine oil from entering the compressor end or turbine end to cause "burning engine oil" or a large amount of oil leakage. The quality of its sealing performance directly affects the working performance, service life and economy of the entire turbocharging system.

The turbocharger has two typical speed conditions: when it is in normal operation, its shaft speed reaches 50000~100000rpm, which is a high-speed working condition; when it is in the idle stage, its shaft speed is 3000~ 5 000rpm, this is the low-speed working condition. The boosting capacity of the turbocharger compressor impeller is directly related to the rotational speed. When it is in a low-speed working condition, the boosting capacity of the compressor is weak, and the pressure at the compressor outlet and the air side is low. This is a negative pressure difference condition. When the oil and gas medium with high pressure is easy to leak to the side of the compressor through the seal, the phenomenon of "oil leakage" occurs; when it is in the high-speed working condition, the pressure at the compressor outlet and the air side is high, which is a positive pressure difference condition. At this time Air will leak to the oil and gas side through the seal, and the phenomenon of "blowby" will occur. At the same time, it is the design goal of turbocharger compressor end seal to control oil leakage under low speed negative pressure difference condition and high speed positive pressure difference condition to control blowby gas. Due to the small axial space between the turbocharger compressor and the bearing cavity, although the contact ring seal commonly used in turbochargers has the advantages of simple structure and low manufacturing cost, it can control oil leakage and channeling. Although the non-contact air film end face seal with pump-out groove on the inner diameter side can better control oil leakage under low-speed conditions, the problem of blow-by under high-speed conditions is still serious.

Contents of the invention

In order to solve the problem that the turbocharger compressor end seal is difficult to achieve both low oil leakage under low-speed negative pressure differential conditions and low blow-by under high-speed positive pressure differential conditions in the axially limited space, the purpose of the present invention is to provide a The utility model relates to a radial double-end oil-gas end-face sealing structure for a turbocharger.

The specific technical scheme is as follows:

A radial double-end oil-gas end face seal structure for a turbocharger, installed between the impeller of the turbocharger compressor and the oil throwing ring of the oil-lubricated bearing chamber, including a moving ring assembly, a stationary ring assembly, a fixed housing and The rotating shaft, the moving ring assembly and the oil throwing ring are installed on the circumferential surface of the rotating shaft and rotate with the rotating shaft. The static ring assembly is located between the fixed shell and the moving ring assembly. The static ring assembly includes the gas side static ring and the oil gas side static ring, and the gas side static ring The gas cavity is formed between the ring, the impeller, the fixed casing and the moving ring assembly, the variable pressure chamber is formed between the gas side static ring, the oil gas side static ring and the moving ring assembly, the oil gas side static ring, the oil throwing ring, the fixed casing An oil-gas cavity is formed between the moving ring assembly, a first compression spring is provided between the fixed housing and the static ring on the gas side, a second compression spring is provided between the static ring on the gas side and the static ring on the oil-gas side, and the static ring on the gas side The end surface at the outer diameter is provided with first dynamic pressure grooves uniformly distributed along the circumferential direction, and the end surface of the inner diameter of the static ring on the oil-gas side is provided with second dynamic pressure grooves uniformly distributed along the circumferential direction.

Further, the first dynamic pressure groove and the second dynamic pressure groove communicate with the variable pressure chamber respectively, and the end face at the inner diameter of the static ring on the gas side is a first sealing dam, and the first sealing dam is located between the first dynamic pressure groove and the gas chamber Between, the end face at the outer diameter of the static ring on the oil-gas side is a second seal dam, and the second seal dam is located between the second dynamic pressure groove and the oil-gas chamber.

Further, the opening numbers of the first dynamic pressure grooves and the second dynamic pressure grooves are 4-60 respectively.

Further, the numbers of the first compression springs and the second compression springs are 3-18 respectively.

Further, a first auxiliary sealing ring is provided between the static ring on the gas side and the fixed housing, and a second auxiliary sealing ring is provided between the static ring on the oil gas side and the static ring on the gas side.

Further, the moving ring assembly includes a moving ring and a shaft sleeve, a variable pressure chamber is formed between the moving ring and the static ring on the gas side and the static ring on the oil-gas side, and the shaft sleeve is located between the moving ring and the impeller.

Further, the gas chamber is connected to the outlet of the impeller, and when the rotation speed of the rotating shaft is 3-5kr/min, a millimeter-level gap is formed between the static ring on the gas side and the end surface of the moving ring, and a micron-level gap is formed between the static ring and the end surface of the moving ring on the oil-gas side; When the rotation speed of the rotating shaft is 50~100kr/min, a micron gap is formed between the gas side static ring and the end face of the moving ring, and a micron gap is formed between the oil gas side static ring and the end face of the moving ring.

The beneficial effects of the present invention are:

1) Both the end face of the static ring on the gas side and the end face of the static ring on the oil-gas side are provided with dynamic pressure grooves, and the dynamic pressure grooves are connected to the variable pressure chamber, and the gas can be pumped into the sealing end face to realize the non-contact operation of the dynamic and static rings, thereby realizing The zero wear of the end face of the sealing ring significantly prolongs the service life and reliability of the sealing structure;

2) Under the condition of low-speed negative pressure difference, the end faces of the static ring and the moving ring on the gas side have a millimeter-level gap without sealing effect, which can avoid collision and friction on the sealing end faces to the greatest extent. The end faces of the static ring and the moving ring on the oil and gas side are micron The stage gap is responsible for the sealing function. The dynamic pressure groove opened at the inner diameter of the static ring on the oil-gas side can pump air into the sealing gap and form a local high pressure, thereby effectively preventing the leakage of the oil-gas medium in the oil-gas cavity and achieving excellent low oil leakage characteristics;

3) Under the condition of high pressure and positive pressure difference, there are micron gaps between the static ring on the gas side, the static ring on the oil and gas side, and the dynamic pressure end face. The medium in the chamber is pumped into the sealing gap to block the leakage of higher-pressure air on the inner diameter side and achieve excellent low blow-by characteristics;

4) In the radial double-end seal structure, two sets of seals are arranged radially, which has the advantages of small axial space size and compact structure.

Description of drawings

Fig. 1 is a schematic diagram of the structure of the radial double-face seal under the condition of high-speed positive pressure difference of the present invention;

Fig. 2 is a schematic diagram of the radial double-end seal structure under the condition of low-speed negative pressure difference of the present invention;

Fig. 3 is a schematic diagram of the end face structure of the gas side static ring seal of the present invention;

Fig. 4 is a schematic diagram of the end face structure of the oil-gas side static ring seal of the present invention;

Fig. 5 is an axial force analysis diagram of the static ring on the gas side of the present invention;

Fig. 6 is an axial force analysis diagram of the static ring on the oil and gas side of the present invention.

In the figure: 1. impeller; 2. oil throwing ring; 3. moving ring assembly; 31. moving ring; 32. shaft sleeve; 4. static ring assembly; 41. gas side static ring; 411. first dynamic pressure groove; 412. The first sealing dam; 413. The first auxiliary sealing ring; 42. The static ring on the oil and gas side; 421. The second dynamic pressure groove; 422. The second sealing dam; 423. The second auxiliary sealing ring; 43. The first compression Spring; 44, second compression spring; 5, fixed housing; 6, gas cavity; 7, rotating shaft; 8, variable pressure cavity; 9, oil-gas cavity.

Detailed ways

The implementation of the present invention is further described in detail in conjunction with the accompanying drawings.

Referring to Figures 1 to 4, a radial double-end oil-gas end face seal structure for a turbocharger is installed between the impeller 1 of the turbocharger compressor and the oil throwing ring 2 of the oil-lubricated bearing chamber. The seal structure includes a dynamic The ring assembly 3, the static ring assembly 4, the fixed housing 5 and the rotating shaft 7, the moving ring assembly 3 includes a moving ring 31 and a shaft sleeve 32, and the shaft sleeve 32, the moving ring 31 and the oil throwing ring 2 are sequentially arranged on the circumferential surface of the rotating shaft 7 , rotates with the rotation of the rotating shaft 7, the static ring assembly 4 includes a gas side static ring 41 and an oil gas side static ring 42, the gas side static ring 41 and the oil gas side static ring 42 are arranged between the moving ring assembly 3 and the fixed housing 5 Between the gas side static ring 41, the impeller 1, the fixed casing 5 and the moving ring assembly 3, a gas chamber 6 is formed, and the gas side static ring 41, the oil gas side static ring 42 and the moving ring 31 form a variable pressure chamber 8 The oil-gas side static ring 42, the oil throwing ring 2, the fixed housing 5 and the moving ring 31 form an oil-gas chamber 9, and a first compression spring 43 is arranged between the fixed housing 5 and the gas-side static ring 41 to control the gas The side static ring 41 provides closing force, and a second compression spring 44 is provided between the gas side static ring 41 and the oil gas side static ring 42 to generate an opening force on the gas side static ring 41, and the force on the oil gas side static ring 42 is Expressed as a closing force, the first compression spring 43 and the second compression spring 44 are in a compressed state when they are working, and both adopt cylindrical helical compression springs, and the numbers of the first compression spring 43 and the second compression spring 44 are 3-18 respectively The end surface at the outer diameter of the static ring 41 on the gas side is provided with first dynamic pressure grooves 411 uniformly distributed along the circumferential direction. When the moving ring 31 rotates, the first dynamic pressure grooves 411 can pump the gas in the variable pressure chamber 8 into the seal. Pressurize after the gap, thereby generating the opening force to push away the static ring 41 on the gas side. The end surface at the inner diameter of the static ring 42 on the oil gas side is provided with second dynamic pressure grooves 421 uniformly distributed along the circumferential direction. The second dynamic pressure grooves 421 can be variable The gas in the pressure chamber 8 increases after being pumped into the sealing gap, thereby generating the opening force of the static ring 42 on the oil-gas side. The pressure groove 411 and the second dynamic pressure groove 421 communicate with the variable pressure chamber 8 respectively, and the end face at the inner diameter of the static ring 41 on the gas side is the first sealing dam 412, and the first sealing dam 412 is located between the first dynamic pressure groove 411 and the gas chamber. 6, the end surface at the outer diameter of the oil-gas side static ring 42 is the second seal dam 422, the second seal dam 422 is located between the second dynamic pressure groove 421 and the oil-gas chamber 9, the gas-side static ring 41 and the fixed housing 5 A first auxiliary sealing ring 413 is provided between them to block the leakage passage between the two, and a second auxiliary sealing ring 423 is provided between the oil gas side static ring 42 and the gas side static ring 41,

Referring to Figures 1, 2, 5 and 6, the axial force analysis is carried out on the static ring 41 on the gas side and the static ring ₄₂ on the oil-gas side. When the rotating shaft 7 rotates at a low speed, the medium pressure p1 _is relatively small because of the weak pressurization capacity of the impeller 1; when the rotating shaft 7 rotates at a high speed, the medium pressure p1 is relatively large due to the strong pressurizing capacity of the impeller ₁ , the medium pressure in the oil-gas chamber 9 is p ₂ , the medium pressure basically does not change with the rotation speed of the rotating shaft 7 and remains a constant value, the medium pressure in the variable pressure chamber 8 is p ₃ , when the gas side static ring 41, When the sealing gap between the static ring 42 on the oil and gas side and the _end face _of the moving ring 31 is on the order of microns, the value of p3 is between p1 _and p2 ; , and when the gap between the stationary ring 42 on the oil and gas side and the end surface of the moving ring 31 is micron-scale, the value of p ₃ is equal to p ₁ .

The left end surface area of the gas side static ring 41 in the gas chamber 6 is A ₁ , then the closing force generated by the medium in the gas chamber 6 on the gas side static ring 41 is p ₁ A ₁ , and the gas side static ring 41 is in the oil gas chamber 9 The area of the right end surface of the oil-gas side static ring 42 in the oil-gas chamber 9 _is A ₂₂ and A ₂₃ respectively, and the opening force generated by the medium in the oil-gas chamber 9 on the gas-side static ring 41 is p ₂ A ₂₁ , the net closing force on the oil and gas side static ring 42 is p ₂ ( A ₂₂ - A ₂₃ ), the area of the right end surface of the gas side static ring 41 in the variable pressure chamber 8 is A ₃₁ , and the oil and gas side The area of the left end surface of the static ring 42 in the variable pressure chamber 8 is A ₃₂ , then the opening force generated by the medium in the variable pressure chamber 8 on the static ring 41 on the gas side is p ₃ A ₃₁ , and the opening force on the static ring 42 on the oil and gas side is p 3 A 31 . The closing force is p ₃ A ₃₂ , both the first compression spring 43 and the second compression spring 44 are in the compressed state in the working state, and the closing force generated by the first compression spring 43 on the static ring 41 on the gas side is F _sp1 , and the second compression spring 43 is in a compressed state. The spring force of the compression spring 44 is F _sp2 , which acts as an opening force for the static ring 41 on the gas side, and a closing force for the static ring 42 on the oil-gas side; it should be noted that the spring force is proportional to the spring compression amount, as As the amount of spring compression increases, the spring force will gradually increase. The friction force between the gas side static ring 41 and the fixed housing 5 is F _f1 , and the friction force between the oil gas side static ring 42 and the gas side static ring 41 is F _f2 , but the direction of the friction force is not determined. Under the action of the first dynamic pressure groove 411, the bearing capacity of the fluid film produced by the gas side static ring 41 and the end surface of the moving ring 31 is F _o1 ; The resulting fluid film carrying capacity is F _o2 .

Taking the static ring 41 on the gas side as the force analysis object, when it is in a balanced state, its axial force satisfies: F _sp1 + p ₁ A ₁ ± F _f1 ± F _f2 = p ₂ A ₂₁ + p ₃ A ₃₁ + F _sp2 + F _o1 . When the rotating shaft 7 runs at a low speed, that is, the rotational speed of the rotating shaft ₇ is 3~5kr/min, the medium pressure p1 of the gas chamber 6 is small, that is, the closing force of the static ring 41 on the gas side is small, and the net effect of the opening force and the closing force The force makes the static ring 41 on the gas side move to the left. During this process, the spring force F _sp1 of the first compression spring 43 increases, and the spring force F _sp2 of the second compression spring 44 decreases. When the gap between the end faces of the moving ring 31 increases to the millimeter level, the medium pressure p ₃ in the variable pressure chamber 8 also gradually decreases and approaches the pressure p ₁ in the gas chamber 6. The combined effect of these three factors increases the closing force and The opening force decreases, and when the static ring 41 on the gas side moves to a certain position, the opening force and the closing force reach a balance again, and at this time, the static ring 41 on the gas side reaches a new equilibrium state. It can be seen that the gap between the end faces of the static ring 41 on the gas side and the end face of the moving ring 31 is on the order of millimeters, that is, the seal on the inner diameter side does not actually function as a seal. When the rotating shaft 7 runs at high speed, that is, the rotating speed of the rotating shaft 7 is 50~100kr/min, the medium pressure _p1 of the gas chamber 6 is relatively large, that is, the closing force on the static ring 41 on the gas side is relatively large, and the static ring 41 and the dynamic ring on the gas side are relatively large. The gap between the end faces of the ring 31 must be maintained at a small micron scale, because the opening force generated by the hydrodynamic pressure on the sealing end face increases rapidly as the sealing gap decreases. The seal opening force F _o1 generated by the dynamic pressure groove 411 is relatively large to balance the relatively large seal closing force.

Taking the static ring 42 on the oil and gas side as the force analysis object, when it is in a balanced state, its axial force satisfies: F _sp2 + p ₂ A ₂₂ + p ₃ A ₃₂ ± F _f1 ± F _f2 = p ₂ A ₂₃ + F _o2 . When the rotating shaft 7 runs at a low speed, the medium pressure p3 in the variable pressure chamber 8 becomes smaller, and the spring force F _sp2 of the second compression spring 44 decreases due to the _reduction of the compression amount, that is, the closing force of the stationary ring 42 on the oil and gas side decrease; at low speeds, the dynamic pressure effect of the second dynamic pressure groove 421 is weak, and the opening force F o2 generated by it is also small, and the small sealing closing force makes the gap between the static ring 42 on the oil-gas side and the end face of the moving ring 31 It is easier to form a stable micron-scale fluid film. When the rotating shaft 7 runs at high speed, because the gas with relatively high pressure in the gas chamber 6 leaks into the variable pressure chamber 8 through the gap between the gas side static ring 41 and the end face of the moving ring 31, the gas pressure in the variable pressure chamber 8 is relatively high at this time. , the oil-gas side static ring 42 receives a larger closing force; while the dynamic pressure effect of the second dynamic pressure groove 421 is stronger at high speeds, the opening force F _o2 generated by it is also larger, and at this time the oil-gas side static ring 42 is also The balance of opening force and closing force can be achieved under certain micron-scale gap conditions.

When it is in the low-speed negative pressure difference condition, there is a millimeter-level gap between the gas side static ring 41 and the end surface of the moving ring 31 and does not play a sealing role, and there is a micron-level gap between the oil-gas side static ring 42 and the end surface of the moving ring 31 to play the main sealing role. Function; at this time, the pressure p ₂ of the oil-gas medium in the oil-gas chamber 9 is higher than the air pressure p ₁ in the gas chamber 6, and the second dynamic pressure groove 421 opened on the inner diameter side of the end surface of the static ring 42 on the oil-gas side can pump air into the sealing gap and increase pressure, thereby preventing the oil-gas medium with high pressure in the oil-gas chamber 9 from leaking to the gas chamber 6, and has good low oil leakage characteristics.

When in high-speed positive differential pressure condition, there are micron-level gaps between the gas side static ring 41, the oil gas side static ring 42 and the moving ring 31, so both inner and outer seals play a sealing role. At this time, the air medium pressure p1 in the gas chamber ₆ is higher than the oil-gas medium pressure p2 in the oil-gas chamber ₉ and the medium pressure _p3 in the variable pressure chamber 8, and the first dynamic pressure set on the outer diameter side of the end surface of the static ring 41 on the gas side The groove 411 can pump the medium in the variable pressure chamber 8 into the sealing gap and pressurize it, thereby preventing the high-pressure air in the gas chamber 6 from leaking to the oil-gas chamber 9, thus having good low blow-by characteristics.

The content described in the embodiments of this specification is only an enumeration of the implementation forms of the inventive concept. The protection scope of the present invention should not be regarded as limited to the specific forms stated in the embodiments. Equivalent technical means that personnel can think of according to the concept of the present invention.

Claims (7)

1. A radial double-end face oil-gas end face seal structure for a turbocharger, which is installed between the impeller (1) of the turbocharger compressor and the oil throwing ring (2) of the oil-lubricated bearing cavity, and is characterized in that it includes a dynamic The ring assembly (3), the static ring assembly (4), the fixed housing (5) and the rotating shaft (7), the moving ring assembly (3) and the oil throwing ring (2) are installed on the circumferential surface of the rotating shaft (7), and follow the rotating shaft ( 7) Turn, the static ring assembly (4) is located between the fixed housing (5) and the dynamic ring assembly (3), the static ring assembly (4) includes the gas side static ring (41) and the oil gas side static ring (42), The gas chamber (6) is formed between the gas side static ring (41), the impeller (1), the fixed casing (5) and the moving ring assembly (3), the gas side static ring (41), the oil gas side static ring (42) The variable pressure chamber (8) is formed between the moving ring assembly (3), and the oil-gas cavity (9), the first compression spring (43) is provided between the fixed housing (5) and the gas side static ring (41), and the gas side static ring (41) and the oil gas side static ring (42) are provided with The second compression spring (44), the outer diameter end surface of the gas side static ring (41) is provided with the first dynamic pressure grooves (411) uniformly distributed along the circumferential direction, and the inner diameter end surface of the oil gas side static ring (42) is provided with circumferentially uniform first dynamic pressure grooves (411). The second dynamic pressure groove (421) of the cloth. 2. A radial double-end oil-gas end face seal structure for a turbocharger according to claim 1, characterized in that the first dynamic pressure groove (411) and the second dynamic pressure groove (421) are respectively connected to the variable pressure chamber (8) Connected, the inner diameter of the static ring on the gas side (41) is the first sealing dam (412), and the first sealing dam (412) is located between the first dynamic pressure groove (411) and the gas chamber (6), The end surface at the outer diameter of the oil-gas side static ring (42) is a second seal dam (422), and the second seal dam (422) is located between the second dynamic pressure groove (421) and the oil-gas chamber (9). 3. A radial double-end oil-gas end face seal structure for a turbocharger as claimed in claim 2, characterized in that the opening numbers of the first dynamic pressure groove (411) and the second dynamic pressure groove (421) are 4 respectively. -60. 4. The radial double-end oil-gas end face seal structure for a turbocharger according to claim 1, characterized in that the numbers of the first compression springs (43) and the second compression springs (44) are 3-18 respectively. 5. The radial double-end oil-gas end face sealing structure for a turbocharger according to claim 1, characterized in that a first auxiliary sealing ring is provided between the gas side static ring (41) and the fixed housing (5) (413), and a second auxiliary sealing ring (423) is provided between the oil-gas side static ring (42) and the gas side static ring (41). 6. A radial double-end oil-gas end face seal structure for a turbocharger according to claim 1, characterized in that the moving ring assembly (3) includes a moving ring (31) and a shaft sleeve (32), and the moving ring (31 ) and the gas side static ring (41) and the oil gas side static ring (42) form a variable pressure chamber (8), and the shaft sleeve (32) is located between the moving ring (31) and the impeller (1). 7. The radial double-end oil-gas end face seal structure for a turbocharger according to claim 6, characterized in that the gas chamber (6) is connected to the outlet of the impeller (1), and the rotation speed of the rotating shaft (7) is 3~5kr/ min, there is a millimeter gap between the gas side static ring (41) and the end face of the moving ring (31), and a micron gap between the oil and gas side static ring (42) and the end face of the moving ring (31); At 50~100kr/min, a micron-level gap is formed between the gas side static ring (41) and the end face of the moving ring (31), and a micron-level gap is formed between the oil-gas side static ring (42) and the end face of the moving ring (31).

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