Sealing structure of vacuum pump

Abstract

The invention provides a sealing structure of a vacuum pump, and belongs to the technical field of vacuum pumps. The sealing structure solves the problem that an existing sealing structure is poor in sealing effect after being used for a long time. According to the sealing structure of the vacuum pump, the vacuum pump comprises a pump shell and a pump shaft rotationally connected into the pump shell, a working cavity and a lubricating oil cavity are formed in the pump shell, the sealing structure comprises a sealing shaft sleeve arranged on the pump shaft in a sleeving mode and located between the working cavity and the lubricating oil cavity, and a pressing sleeve arranged outside the sealing shaft sleeve in a sleeving mode is fixedly connected into the pump shell; the pump shell and the pressing sleeve are sealed through a sealing ring, an air inlet through hole communicated with the outside is formed in the pressing sleeve, at least two elastic washers located on the left side and the right side of an air inlet channel respectively are arranged between the pressing sleeve and the sealing shaft sleeve, one end of the sealing shaft sleeve protrudes in the radial direction to form an abutting stop shoulder, and the abutting stop shoulder abuts against the pressing sleeve in the axial direction. At least three annular sealing cavities are formed in the inner wall of the sealing shaft sleeve. The sealing structure of the vacuum pump can achieve a good sealing effect after being used for a long time.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of vacuum pumps and relates to a sealing structure of a vacuum pump. BACKGROUND

[0002] The pump cavity of a vacuum pump is divided into a working cavity and a lubricating cavity, and the working cavity and the lubricating cavity need to be relatively sealed during operation to avoid mutual influence, so that the medium in the working cavity and the lubricating oil in the lubricating cavity need to be isolated by a sealing structure.

[0003] The existing sealing structure, such as Chinese Patent Application

Application Publication No. CN119802226A

[0004] The above structure is provided with a shaft sleeve on the pump shaft, a first O-shaped ring is arranged between the shaft sleeve and the pump shaft, and a sealing ring made of special material is used, so that the first O-shaped ring can still meet the sealing requirements after being subjected to irradiation and high temperature. However, when the pump shaft of the vacuum pump is at high temperature, not only is the high temperature affected, but also the pump shaft may expand, which causes the shaft sleeve to be extruded, affects the cooperation between the shaft sleeve and the pump shaft, and only relies on the sealing ring. After long-term use, the sealing performance will be reduced due to aging, and the sealing ring is not easy to replace after aging, so that the sealing structure of the pump shaft is prone to failure after long-term use, affecting the sealing effect of the vacuum pump during long-term use. SUMMARY

[0005] The purpose of the present application is to solve the above-mentioned problems existing in the prior art, and a sealing structure of a vacuum pump is provided. The technical problem to be solved by the present application is how to solve the problem of poor sealing effect of the existing sealing structure after long-term use.

[0006] The purpose of the present application can be achieved by the following technical scheme:

[0007] The utility model provides a sealing structure of vacuum pump, vacuum pump includes pump shell and pump shaft rotationally connected in pump shell, and the pump shell has working cavity and lubricating oil cavity, characterized by, the sealing bushing of the utility model is sleeved on the pump shaft and is located between working cavity and lubricating oil cavity, the compression sleeve of the utility model is fixedly connected in the pump shell and is sleeved outside the sealing bushing, the pump shell and the compression sleeve are sealed through the sealing ring, the compression sleeve is provided with the air inlet through -hole that communicates with the outside, at least two elastic washers are arranged between the compression sleeve and the sealing bushing and are located on the left and right sides of the air inlet channel respectively, one end of the sealing bushing is radially protruding and forms the abutting shoulder, the abutting shoulder and the compression sleeve abut in the axial direction, the inner wall of the sealing bushing is provided with at least three annular sealing cavities, and the air inlet through -hole is communicated with the middle sealing cavity, the inner wall of the sealing bushing and the outer wall of the pump shaft form the sealing channel that communicates with all sealing cavities and penetrates the both ends of the sealing bushing in the axial direction.

[0008] The utility model discloses a sealing structure of vacuum pump, vacuum pump includes pump shell and pump shaft rotationally connected in pump shell, and the pump shell has working cavity and lubricating oil cavity, characterized by, the sealing bushing of the utility model is sleeved on the pump shaft and is located between working cavity and lubricating oil cavity, the compression sleeve of the utility model is fixedly connected in the pump shell and is sleeved outside the sealing bushing, the pump shell and the compression sleeve are sealed through the sealing ring, the inner wall of the sealing bushing and the outer wall of the pump shaft form the sealing channel, the compression sleeve realizes the radial positioning of the sealing bushing through the elastic washer, one end of the sealing bushing is radially protruding and forms the abutting shoulder, the abutting shoulder and the compression sleeve abut in the axial direction through the abutting shoulder of the sealing bushing, realize the axial location of the sealing bushing, the air inlet through -hole that communicates with the outside compressed gas is seted up on the compression sleeve, the compressed gas is entered into one of the sealing cavities in the middle of the sealing bushing from the air inlet through -hole, and the compressed gas flows to the sealing channel and other sealing cavities through the sealing cavity, and finally flows out from the both ends of the sealing bushing through the sealing channel, and the both ends of the sealing bushing are communicated with working cavity and lubricating oil cavity respectively, so can separate medium and lubricating oil, and the sealing cavities are arranged on both sides of the sealing cavity in the middle of the sealing bushing, when the compressed gas is introduced into one of the sealing cavities from the air inlet through -hole, the air pressure will gradually reduce along with the gradual flow of the compressed gas.

[0009] The arrangement of multiple sealing cavities forms a pressure drop zone in the sealing channel. Through the series arrangement of multiple annular sealing cavities, when the high-pressure gas enters the sealing channel, the sealing channel is relatively narrow, which can increase the flow rate of the high-pressure gas and preliminarily reduce the pressure. When the high-pressure gas enters the sealing cavity, the space suddenly expands, which reduces the flow rate of the high-pressure gas, and the pressure of the high-pressure gas gradually stabilizes in the cavity, forming a pressure node lower than the previous sealing cavity. Through the continuous throttling and pressure stabilization of multiple sealing cavities, the gas pressure gradually decays from the initial high pressure value, and the total pressure difference is decomposed into multiple local small pressure differences, which gradually decreases to the level close to the low pressure side, so that the leakage pressure difference is greatly reduced, and the leakage amount of high-pressure gas is reduced. During the operation of the vacuum pump, the temperature rises, causing the pump shaft to expand. The sealing sleeve is arranged between the pump shafts, and the sealing sleeve and the pump shaft are separated by the sealing channel. At this time, the deformation of the pump shaft does not affect the arrangement of the sealing sleeve. The non-contact sealing prolongs the service life of the sealing sleeve. The cooperation of multiple sealing cavities and sealing channels forms a structure for forming a pressure drop zone to achieve stable sealing, thereby achieving good sealing effect after long-term use.

[0010] In the sealing structure of the vacuum pump, all the sealing cavities are arranged along the axial direction of the sealing sleeve, and the openings of the sealing cavities are all directed towards the pump shaft.

[0011] The arrangement of the structure enables the sealing cavities to be arranged along the axial direction of the sealing sleeve, so that the pressure difference of the high-pressure gas gradually decays along the sealing sleeve. The arrangement of the openings of the sealing cavities enables the high-pressure gas to quickly enter the sealing cavities, thereby facilitating the gradual decay of the pressure difference and achieving good sealing effect. The non-contact sealing ensures that the sealing effect can always be maintained well during long-term use.

[0012] In the sealing structure of the vacuum pump, the sealing channel is an annular channel formed between the inner wall of the sealing sleeve and the outer wall of the pump shaft and extending in the axial direction, and the two ends of the sealing channel are in communication with the working cavity and the lubricating oil cavity, respectively.

[0013] The sealing channel is arranged in an annular shape, which ensures that the high-pressure gas can be uniformly distributed around the pump shaft to achieve good sealing effect, and facilitates the formation of a pressure drop zone, thereby maintaining the sealing effect during long-term use.

[0014] In the sealing structure of the vacuum pump, the inner wall of the pressure sleeve is provided with an annular buffer cavity, the buffer cavity is in communication with the gas inlet hole, and the buffer cavity is in communication with one of the sealing cavities located in the middle of the sealing sleeve.

[0015] The buffer cavity is arranged so that the compressed gas entering the air inlet through hole can accumulate in the buffer cavity, the compressed gas from the outside can quickly enter the compression sleeve through the air inlet through hole, and the compressed gas can be stably introduced into the sealing cavity through the accumulation in the buffer cavity, so as to avoid a large impact on the sealing cavity, affect the sleeving of the sealing sleeve and the pump shaft, and thus prolong the service life of the sealing sleeve as much as possible while ensuring the sealing stability.

[0016] In the sealing structure of the vacuum pump, the compression sleeve and the sealing sleeve have a gap, the compression sleeve is provided with a mounting groove corresponding to the elastic washer on both sides of the buffer cavity, the elastic washer is arranged in the corresponding mounting groove, and the elastic washer is partially located outside the gap and always abuts against the outer wall of the sealing sleeve.

[0017] The gap is arranged so that the sealing sleeve and the compression sleeve are only abutted in the axial direction by the elastic washer. The elastic washer has certain elasticity to stably limit the sealing sleeve, and only abuts in the axial direction between the compression sleeve and the sealing sleeve, so that the axial abutment and the radial positioning do not interfere with each other, thereby facilitating the installation and positioning of the sealing sleeve.

[0018] In the sealing structure of the vacuum pump, the mounting sleeve is fixedly connected to the pump shell, the mounting sleeve is sleeved outside the compression sleeve, the air inlet channel is formed in the mounting sleeve, the air gap is formed between the inner side wall of the mounting sleeve and the outer side wall of the compression sleeve, the air gap communicates the air inlet channel with the air inlet through hole, and the air inlet channel and the air inlet through hole are arranged in the axial direction.

[0019] The mounting sleeve is arranged to position the compression sleeve in the radial direction, and the external compressed air enters the corresponding sealing cavity from the air inlet channel through the air gap and the air inlet through hole. In order to improve the pressure difference and the flow rate of the external compressed air, the external compressed air can quickly flow into the air inlet through hole, the sealing effect of the sealing sleeve is improved, and the air inlet channel and the air inlet through hole are arranged in the axial direction to avoid the external compressed air in the air inlet channel directly entering the air inlet through hole, thereby ensuring the pressure increasing effect of the external compressed air in the air gap.

[0020] In the sealing structure of the vacuum pump, the air gap is annular, the air inlet channel communicates with one end of the air gap, and the air inlet through hole communicates with the other end of the air gap.

[0021] The shape of the air gap can increase the flow rate of the external compressed air entering the air gap, and facilitate the staggered arrangement of the air inlet through hole and the air inlet channel, thereby improving the sealing effect of the sealing structure.

[0022] In the sealing structure of the vacuum pump, the sealing sleeve is radially provided with a sealing air inlet hole, one of the sealing cavities is communicated with the air inlet hole, and the sealing air inlet hole and the air inlet hole are axially staggered.

[0023] The structure is arranged so that the sealing sleeve needs to pass through the sealing air inlet hole and then enter the sealing cavity when compressed air is introduced, so that the compressed air flowing out of the buffer cavity can be accelerated at the sealing air inlet hole, and the compressed air in the air inlet hole is avoided from directly flowing into the sealing cavity through the staggered arrangement of the sealing air inlet hole and the air inlet hole, thereby ensuring that the compressed air will enter the sealing cavity after being buffered and accumulated in the buffer cavity, that is, stable sealing can be achieved, and that the sealing sleeve is avoided from being subjected to a large impact, thereby prolonging the service life of the sealing sleeve.

[0024] In the sealing structure of the vacuum pump, one end of the pressing sleeve is radially protruded to form a limiting shoulder, one end of the mounting sleeve is axially abutted against the limiting shoulder, the outer side wall of the pressing sleeve is radially contracted to form a first space wall, the inner side wall of the mounting sleeve is radially outwardly recessed to form a second space wall, and the first space wall and the second space wall jointly form the air passing gap.

[0025] The limiting shoulder is arranged so that the mounting sleeve and the pressing sleeve can be axially limited, and the first space wall and the second space wall are designed so that the air passing gap is formed, and the mounting of the pressing sleeve and the mounting sleeve is more convenient and simple.

[0026] In the sealing structure of the vacuum pump, the pump shaft is sleeved with a centrifugal dust blocking ring, one end of the centrifugal dust blocking ring close to the sealing sleeve is protruded to form a blocking ring, the blocking ring is located on the outer side of the abutting shoulder, and the centrifugal dust blocking ring and the sealing sleeve have a space.

[0027] Since there is usually a small amount of solid medium in the working cavity, the centrifugal dust blocking ring is used to throw out the solid medium with a large molecular weight, and in order to avoid the solid medium with a large molecular weight from entering the sealing channel, the abutting shoulder and the blocking ring are arranged to improve the obstruction of the solid medium entering the sealing channel, so that the sealing channel only needs to blow out the solid medium with a small molecular weight, and the sealing effect of the sealing structure is improved.

[0028] In the sealing structure of the vacuum pump, the pump shaft is further sleeved with a centrifugal sealing ring arranged close to the working cavity, the centrifugal sealing ring is provided with centrifugal teeth, one end of the centrifugal sealing ring away from the working cavity is abutted against the centrifugal dust blocking ring, the pump housing is fixedly connected with a positioning bushing, the positioning bushing is sleeved on the outer side of the centrifugal sealing ring, the positioning bushing and the centrifugal sealing ring are arranged opposite to each other, and the positioning bushing is provided with sealing teeth meshing with the centrifugal teeth.

[0029] The centrifugal sealing ring further enhances the obstruction of the medium in the working chamber, and the cooperation between the positioning bushing and the centrifugal sealing ring further improves the sealing effect.

[0030] In the sealing structure of the vacuum pump described above, the mounting sleeve abuts against the positioning bushing, the lower end of the mounting sleeve is provided with a flow guide channel and an exhaust port communicating with the flow guide channel, and a receiving cavity is formed between the centrifugal dust baffle ring and the inner side wall of the mounting sleeve, and the receiving cavity is communicating with the exhaust port through the flow guide channel.

[0031] The design of the exhaust port and the flow channel allows both gas and some of the medium in the working chamber to be discharged through the exhaust port, preventing the rapid discharge of large molecular weight solid media without flowing into the sealing gap, thus improving the sealing effect of the sealing structure.

[0032] Compared with existing technologies, the sealing structure of this vacuum pump has the following advantages:

[0033] 1. The design of multiple sealing cavities creates a pressure drop zone within the sealing channel. Through the series arrangement of multiple annular sealing cavities, when high-pressure gas enters the relatively narrow sealing channel, the gas velocity initially increases and the pressure drops. As the high-pressure gas enters the sealing cavity, the space suddenly expands, reducing the gas velocity and gradually stabilizing the pressure within the cavity, forming a pressure node lower than the previous sealing cavity. Through continuous throttling and pressure stabilization by multiple sealing cavities, the gas pressure gradually decreases from the initial high pressure value. This breaks down the total pressure difference into multiple smaller local pressure differences, progressively reducing them to near the low-pressure side level. This significantly reduces the leakage pressure difference, decreasing the amount of high-pressure gas leakage and ensuring good sealing performance even after prolonged use without needing to replace the sealing bushing.

[0034] 2. When compressed air is introduced into the sealing bushing, it needs to pass through the sealed air inlet before entering the sealing cavity. This allows the compressed air flowing out of the buffer cavity to be accelerated at the sealed air inlet. Furthermore, by staggering the sealed air inlet and the air inlet, the compressed air from the air inlet is prevented from flowing directly into the sealing cavity. This ensures that the compressed air is buffered and accumulated in the buffer cavity before entering the sealing cavity, achieving a stable seal and avoiding significant impact on the sealing bushing, thus extending its service life. Attached Figure Description

[0035] Figure 1 This is a partial cross-sectional view of the present invention.

[0036] Figure 2 yes Figure 1 A magnified view of a portion of point A in the middle.

[0037] Figure 3 is Figure 1 is a local enlarged view of B in figure.

[0038] In the figure, 1, pump shell; 11, working cavity; 12, lubricating oil cavity; 2, pump shaft; 3, sealing sleeve; 31, sealing cavity; 32, sealing channel; 33, sealing air inlet hole; 34, abutting shoulder; 4, pressing sleeve; 41, air inlet through hole; 42, buffer cavity; 43, clearance; 44, mounting groove; 45, limiting shoulder; 46, clearance wall one; 5, elastic washer; 6, mounting sleeve; 61, air inlet channel; 62, air passing gap; 63, clearance wall two; 64, flow guide channel; 65, air outlet; 7, centrifugal dust blocking ring; 71, blocking ring; 72, clearance space; 8, centrifugal sealing ring; 81, centrifugal tooth; 9, positioning bushing; 91, sealing tooth; 10, containing cavity; 101, sealing ring. DETAILED DESCRIPTION

[0039] The following is a specific embodiment of the present application and further describes the technical solutions of the present application in conjunction with the accompanying drawings, but the present application is not limited to these embodiments.

[0040] As Figure 1 shown, the sealing structure of the vacuum pump includes a pump shell 1 and a pump shaft 2 rotatably connected in the pump shell 1, and the pump shell 1 has a working cavity 11 and a lubricating oil cavity 12.

[0041] Specifically, as Figure 1 and Figure 2 shown, the sealing structure includes a sealing sleeve 3 sleeved on the pump shaft 2 and located between the working cavity 11 and the lubricating oil cavity 12, the pump shell 1 is fixedly connected with a pressing sleeve 4 sleeved outside the sealing sleeve 3, the pump shell 1 and the pressing sleeve 4 are sealed by a sealing ring 101, the pressing sleeve 4 is provided with an air inlet through hole 41 communicating with the outside, at least two elastic washers 5 are arranged between the pressing sleeve 4 and the sealing sleeve 3 and located on the left and right sides of the air inlet through hole 41, one end of the sealing sleeve 3 is radially protruded to form an abutting shoulder 34, the abutting shoulder 34 abuts with the pressing sleeve 4 in the axial direction, at least three annular sealing cavities 31 are formed on the inner wall of the sealing sleeve 3, the air inlet through hole 41 is communicated with the middle sealing cavity 31, and the inner wall of the sealing sleeve 3 and the outer wall of the pump shaft 2 form a sealing channel 32 communicating with all the sealing cavities 31 and penetrating through both ends of the sealing sleeve 3 in the axial direction.

[0042] The pump shell 1 has a working cavity 11 and a lubricating oil cavity 12, a sealing sleeve 3 is sleeved on the pump shaft 2, the sealing sleeve 3 is sleeved with a pressing sleeve 4, the pressing sleeve 4 is fixedly connected in the pump shell 1, and the pressing sleeve 4 and the pump shell 1 are sealed by a sealing ring 101, a sealing channel 32 is formed between the inner side wall of the sealing sleeve 3 and the outer side wall of the pump shaft 2, the pressing sleeve 4 realizes radial positioning of the sealing sleeve 3 through an elastic gasket 5, one end of the sealing sleeve 3 is protruded to form an abutting shoulder 34, the abutting shoulder 34 of the sealing sleeve 3 axially abuts against the pressing sleeve 4, thereby realizing axial positioning of the sealing sleeve 3, an air inlet hole 41 is formed in the pressing sleeve 4 and communicates with the outside compressed gas, the compressed gas enters one of the sealing cavities 31 in the middle of the sealing sleeve 3 from the air inlet hole 41, the compressed gas flows into the sealing channel 32 and the other sealing cavities 31 through the sealing cavities 31, and finally flows out from both ends of the sealing sleeve 3 through the sealing channel 32, and the two ends of the sealing sleeve 3 communicate with the working cavity 11 and the lubricating oil cavity 12 respectively, so that the medium and the lubricating oil can be separated, and the sealing cavities 31 are arranged on both sides of the sealing cavities 31 in the middle of the sealing sleeve 3, when the compressed gas is introduced into one of the sealing cavities 31 from the air inlet hole 41, the gas pressure gradually decreases with the gradual flow of the compressed gas.

[0043] Here, the multiple sealing cavities 31 are arranged to form a pressure drop zone in the sealing channel 32, through the series arrangement of multiple annular sealing cavities 31, when the high-pressure gas enters the sealing channel 32, the sealing channel 32 is relatively narrow, which can make the flow rate of the high-pressure gas increase and the pressure preliminarily decrease, when the high-pressure gas enters the sealing cavity 31, the space suddenly expands, which makes the flow rate of the high-pressure gas decrease, and the gas pressure of the high-pressure gas gradually stabilizes in the cavity, forming a pressure node lower than the previous sealing cavity 31, thereby through the continuous throttling and pressure stabilization of multiple sealing cavities 31, the gas pressure gradually decays from the initial high pressure value, and the total pressure difference is decomposed into multiple local small pressure differences, which is gradually reduced to the level close to the low pressure side, so that the leakage pressure difference is greatly reduced, and the leakage amount of the high-pressure gas is reduced, when the vacuum pump is running, the temperature will rise, which causes the pump shaft 2 to expand, the sealing sleeve 3 is arranged between the pump shaft 2, the sealing sleeve 3 and the pump shaft 2 are separated by the sealing channel 32, at this time, the deformation of the pump shaft 2 does not affect the arrangement of the sealing sleeve 3, the contactless sealing is adopted, the service life of the sealing sleeve 3 is prolonged, and through the cooperation of multiple sealing cavities 31 and the sealing channel 32, stable sealing can be realized by forming a pressure drop zone structure during use, and good sealing effect can be achieved after long-term use.

[0044] As Figure 1 and Figure 2As shown in the drawings, all the sealing cavities 31 are arranged along the axial direction of the sealing sleeve 3 in sequence, and the openings of the sealing cavities 31 are all directed to the pump shaft 2. The sealing channel 32 is an annular channel extending along the axial direction and is formed between the inner side wall of the sealing sleeve 3 and the outer side wall of the pump shaft 2. The two ends of the sealing channel 32 are in communication with the working cavity 11 and the lubricating oil cavity 12 respectively. The inner side wall of the pressing sleeve 4 is provided with an annular buffer cavity 42. The buffer cavity 42 is in communication with the air inlet through hole 41 and the buffer cavity 42 is in communication with one of the sealing cavities 31 located in the middle of the sealing sleeve 3. The pressing sleeve 4 and the sealing sleeve 3 have a clearance 43. The pressing sleeve 4 is provided with a mounting groove 44 corresponding to each elastic gasket 5 on both sides of the buffer cavity 42. The elastic gasket 5 is arranged in the corresponding mounting groove 44, and the elastic gasket 5 is partially located outside the clearance 43 and always abuts against the outer wall of the sealing sleeve 3.

[0045] As shown in the drawings, Figure 1 and Figure 2 The pump housing 1 is fixedly connected with a mounting sleeve 6. The mounting sleeve 6 is sleeved outside the pressing sleeve 4. The mounting sleeve 6 is provided with an air inlet channel 61. The inner side wall of the mounting sleeve 6 and the outer side wall of the pressing sleeve 4 have an air passing gap 62. The air passing gap 62 is in communication with the air inlet channel 61 and the air inlet through hole 41. The air inlet channel 61 and the air inlet through hole 41 are arranged axially offset. The air passing gap 62 is annular. The air inlet channel 61 is in communication with one end of the air passing gap 62. The air inlet through hole 41 is in communication with the other end of the air passing gap 62. The sealing sleeve 3 is provided with a sealing air inlet hole 33 along the radial direction. The sealing air inlet hole 33 is in communication with one of the sealing cavities 31 and the air inlet through hole 41. The sealing air inlet hole 33 and the air inlet through hole 41 are arranged axially offset. One end of the pressing sleeve 4 is protruded along the radial direction to form a limiting stop shoulder 45. One end of the mounting sleeve 6 is abutted on the limiting stop shoulder 45 along the axial direction. The outer side wall of the pressing sleeve 4 is contracted along the radial direction to form a clearance wall one 46. The inner side wall of the mounting sleeve 6 is recessed outward along the radial direction to form a clearance wall two 63. The clearance wall one 46 and the clearance wall two 63 enclose the air passing gap 62.

[0046] As shown in the drawings, Figure 2 and Figure 3As shown, the centrifugal dust ring 7 is sleeved on the pump shaft 2, and a protruding ring 71 is formed on one end of the centrifugal dust ring 7 close to the sealing sleeve 3, the protruding ring 71 is located outside the abutting shoulder 34, and the centrifugal dust ring 7 has a space 72 between the centrifugal dust ring 7 and the sealing sleeve 3, the centrifugal sealing ring 8 close to the working cavity 11 is sleeved on the pump shaft 2, the centrifugal sealing ring 8 is provided with centrifugal teeth 81, and one end of the centrifugal sealing ring 8 away from the working cavity 11 abuts against the centrifugal dust ring 7, the positioning bushing 9 is fixed on the pump shell 1, the positioning bushing 9 is sleeved outside the centrifugal sealing ring 8, and the positioning bushing 9 is opposite to the centrifugal sealing ring 8, the positioning bushing 9 is provided with sealing teeth 91 engaged with the centrifugal teeth 81, the mounting sleeve 6 abuts against the positioning bushing 9, the lower end of the mounting sleeve 6 is provided with a flow guide channel 64 and an exhaust port 65 communicated with the flow guide channel 64, the centrifugal dust ring 7 and the inner wall of the mounting sleeve 6 form a containing cavity 10, and the containing cavity 10 is communicated with the flow guide channel 64 and the exhaust port 65.

[0047] The specific embodiments described herein are merely illustrative of the spirit of the present application. Those skilled in the art of the present application can make various modifications or supplements to the described specific embodiments or replace them with similar ways, but will not deviate from the spirit of the present application or exceed the scope defined by the appended claims.

Claims

1. A sealing structure for a vacuum pump, the vacuum pump comprising a pump housing (1) and a pump shaft (2) rotatably connected within the pump housing (1), the pump housing (1) having a working chamber (11) and a lubricating oil chamber (12), characterized in that, This sealing structure includes a sealing bushing (3) sleeved on the pump shaft (2) and located between the working chamber (11) and the lubricating oil chamber (12). A pressure sleeve (4) sleeved outside the sealing bushing (3) is fixed inside the pump housing (1). The pump housing (1) and the pressure sleeve (4) are sealed by a sealing ring (101). An air inlet hole (41) communicating with the outside is provided on the pressure sleeve (4). At least two elastic washers are provided between the pressure sleeve (4) and the sealing bushing (3) respectively located on the left and right sides of the air inlet hole (41). 5) One end of the sealing bushing (3) protrudes radially to form abutment shoulder (34), the abutment shoulder (34) abuts against the pressure sleeve (4) axially, at least three annular sealing cavities (31) are provided on the inner wall of the sealing bushing (3), and the air inlet hole (41) is connected to the sealing cavity (31) located in the middle, and a sealing channel (32) is formed between the inner side wall of the sealing bushing (3) and the outer side wall of the pump shaft (2), which communicates with all the sealing cavities (31) and passes through both ends of the sealing bushing (3) axially.

2. The sealing structure of the vacuum pump according to claim 1, characterized in that, All sealing cavities (31) are distributed sequentially along the axial direction of the sealing sleeve (3), and the openings of the sealing cavities (31) all face the pump shaft (2).

3. The sealing structure of the vacuum pump according to claim 1 or 2, characterized in that, The sealing channel (32) is an annular channel that extends axially between the inner wall of the sealing bushing (3) and the outer wall of the pump shaft (2). The two ends of the sealing channel (32) are connected to the working chamber (11) and the lubricating oil chamber (12), respectively.

4. The sealing structure of the vacuum pump according to claim 1 or 2, characterized in that, The inner wall of the pressure sleeve (4) is provided with an annular buffer cavity (42), which is connected to the air inlet hole (41) and is connected to one of the sealing cavities (31) located in the middle of the sealing bushing (3).

5. The sealing structure of the vacuum pump according to claim 4, characterized in that, There is a clearance gap (43) between the pressure sleeve (4) and the sealing bushing (3). The pressure sleeve (4) has mounting grooves (44) on both sides of the buffer cavity (42) that correspond one-to-one with the elastic washer (5). The elastic washer (5) is set in the corresponding mounting groove (44). The elastic washer (5) is partially located outside the clearance gap (43) and always abuts against the outer wall of the sealing bushing (3).

6. The sealing structure of the vacuum pump according to claim 1 or 2, characterized in that, An mounting sleeve (6) is fixedly connected to the pump housing (1). The mounting sleeve (6) is sleeved on the outside of the pressure sleeve (4). An air inlet channel (61) is provided on the mounting sleeve (6). There is an air passage gap (62) between the inner side wall of the mounting sleeve (6) and the outer side wall of the pressure sleeve (4). The air passage gap (62) connects the air inlet channel (61) and the air inlet hole (41). The air inlet channel (61) and the air inlet hole (41) are axially offset.

7. The sealing structure of the vacuum pump according to claim 6, characterized in that, The air gap (62) is annular, the air intake channel (61) is connected to one end of the air gap (62), and the air intake through hole (41) is connected to the other end of the air gap (62).

8. The sealing structure of the vacuum pump according to claim 1 or 2, characterized in that, The sealing bushing (3) has a sealing air inlet hole (33) in the radial direction. The sealing air inlet hole (33) connects one of the sealing cavities (31) with the air inlet hole (41). The sealing air inlet hole (33) and the air inlet hole (41) are offset from each other in the axial direction.

9. The sealing structure of the vacuum pump according to claim 6, characterized in that, One end of the pressure sleeve (4) protrudes radially to form a limiting shoulder (45), and one end of the mounting sleeve (6) presses against the limiting shoulder (45) axially. The outer side wall of the pressure sleeve (4) contracts radially to form a relief wall one (46), and the inner side wall of the mounting sleeve (6) is recessed radially outward to form a relief wall two (63). The relief wall one (46) and the relief wall two (63) together form the above-mentioned air passage gap (62).

10. The sealing structure of the vacuum pump according to claim 9, characterized in that, A centrifugal dust baffle ring (7) is fitted on the pump shaft (2). The centrifugal dust baffle ring (7) has a protrusion at one end near the sealing shaft sleeve (3) to form a retaining ring (71). The retaining ring (71) is located on the outside of the shoulder (34), and there is a clearance space (72) between the centrifugal dust baffle ring (7) and the sealing shaft sleeve (3).

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