Shaft seal pressure reducing assembly and single screw air compressor

Abstract

The present invention discloses a shaft seal decompression assembly and a single-screw air compressor using the shaft seal decompression assembly, wherein the shaft seal decompression assembly includes an upper shell body arranged on a casing, a lower shell body arranged on the lower side of the upper shell body and plugged with the upper shell body to form a first space, and a rotating component and a sealing component arranged in the first space and arranged in sequence from top to bottom along the axial direction of the main rotor; a bearing assembly is arranged at the upper end of the main rotor of the single-screw air compressor, and a shaft seal decompression assembly is arranged at the lower end, so that the main rotor can be rotatably supported on the casing. The present invention sets a shaft seal oil chamber between the casing and the shaft seal decompression assembly to ensure a sealed connection between the main rotor and the casing, thereby achieving the sealing of the compression chamber; the sealing component is equipped with a decompression chamber to ensure the sealing of the connection between the main rotor and the shaft seal decompression assembly, and at the same time, an isolation ring is used to prevent the lubricating oil from directly impacting the main rotor, thereby preventing the compressor from shaking, thereby improving the service life of the main rotor and the sealing component.

Description

Technical Field

[0001] The invention belongs to the technical field of air compressors, and in particular relates to a shaft seal pressure reducing assembly and a single screw air compressor using the shaft seal pressure reducing assembly. Background Art

[0002] The single screw air compressor is composed of a cylindrical screw and two symmetrically arranged plane star wheels, which form a meshing pair and are installed in the main housing. The space enclosed by the screw groove, the inner wall of the main housing, and the tooth surface of the star wheel constitutes the working volume of the compressor. The motor directly drives the screw shaft to rotate, and the screw drives the star wheel to rotate. The gas enters the screw groove from the air intake on the main engine, and is discharged from the exhaust hole on the main housing after being compressed. There is also a spray hole on the main housing to spray the lubricating oil into the working volume, which plays a role in sealing, cooling and lubrication. The current screw air compressor adopts a circulating injection method. The lubricating oil is stored in the oil tank, and the oil pump drives the lubricating oil to enter the oil filter, cooler and oil separator in turn.

[0003] When low-pressure air is sucked into the compression chamber and is compressed into high-pressure gas, the axial force of the screw gradually increases from the low-pressure air intake end to the high-pressure air discharge end. The difference in axial force on the same shaft not only affects the rotation of the screw, causing the screw to vibrate and reduce its service life, but also affects the sealing between components. Summary of the invention

[0004] In order to overcome the above-mentioned defects, the present invention provides a shaft seal pressure reducing assembly and a single-screw air compressor.

[0005] In one aspect, the technical solution adopted by the present invention is to provide a shaft seal decompression assembly, which is arranged on a side of the main rotor of a single-screw air compressor close to the lower end, and is used together with a bearing assembly at the upper end of the main rotor to rotatably support the main rotor on the casing of the compressor, wherein the shaft seal decompression assembly comprises an upper shell provided on the casing, a lower shell provided on the lower side of the upper shell and plugged with the upper shell to form a first space, and a rotating component and a sealing component provided in the first space and arranged in sequence from top to bottom along the axial direction of the main rotor; the main rotor passes through the shaft seal decompression assembly along its axial direction and is connected to a driving source;

[0006] The upper housing is provided with a first branch oil passage communicating with the compressor oil supply system, and the rotating component comprises a first bearing mounted on the upper housing and sleeved on the main rotor;

[0007] The lower housing is provided with a shaft seal oil passage for connecting the first branch oil passage with the first space, a groove is provided on the inner peripheral wall of the lower housing, and the outlet of the shaft seal oil passage is placed on the groove;

[0008] The sealing component is arranged on the lower housing, and includes a dynamic ring and a static ring which are sequentially sleeved on the main rotor from top to bottom, and an isolation ring which is arranged outside the dynamic ring and installed on the lower housing; the dynamic ring is fixedly connected to the main rotor and can rotate with the main rotor, and the static ring is sealed and fixedly connected to the lower housing and has a clearance fit with the main rotor;

[0009] The isolating ring seals the notch of the groove to form a decompression chamber, and a notch is provided on the isolating ring to connect the decompression chamber with the first space.

[0010] As a further improvement of the present invention, the lower side wall of the groove is composed of a horizontal portion and an inclined portion which are arranged in sequence from the bottom of the groove to the inside along the radial direction of the main rotor, and the inclined portion is arranged to be inclined from the outside to the inside and downward, and one side of the lower end face of the isolation ring has six notches in an axial annular array around it, and the top end face of the notch is inclined from the inside to the outside and upward at a set angle, and the starting end of the top end face is on the same horizontal plane as the horizontal portion.

[0011] As a further improvement of the present invention, the upper shell and the lower shell are both provided with through holes for the main rotor to pass through, the outer edge of the upper shell facing the side of the lower shell is provided with an upper flange protruding outward along its radial direction, the lower shell has a lower flange docked with the upper flange, the first branch oil circuit is arranged on the upper flange, and the shaft seal oil circuit is arranged on the lower flange;

[0012] The lower shell body has an installation groove for installing the stationary ring at one end close to the through hole thereon. The axial cross-section of the stationary ring is in the shape of a "7", and its inner circumferential wall is annularly sleeved on the main rotor, and the top surface extends upward from the installation groove and slides against the lower end surface of the moving ring.

[0013] As a further improvement of the present invention, the inner circumferential wall of the lower shell body is respectively formed with abutment surfaces on the upper and lower sides of the groove, which are adapted to the outer circumferential wall of the isolation ring. The lower end of the abutment surface is connected to the notch of the mounting groove through a horizontal supporting surface, and the lower end surface of the isolation ring abuts against the supporting surface.

[0014] As a further improvement of the present invention, the lower housing further comprises an inserting portion inserted into the upper housing, and an upper end surface of the inserting portion positions the outer ring of the first bearing in the upper housing;

[0015] The rotating component also includes a sleeve and a fixing member respectively arranged at the upper and lower ends of the first bearing, and the sleeve and the fixing member are both fixedly attached to the main rotor so as to position the inner ring of the first bearing on the main rotor and rotate with the main rotor. At the same time, the sleeve is also inserted into the through hole of the upper shell and is slidably connected to the through hole.

[0016] On the other hand, the technical solution adopted by the present invention is to provide a single screw air compressor, comprising a casing, a main rotor provided in the casing, and a pair of star rotors provided in the casing and arranged on opposite sides of the main rotor;

[0017] The casing is provided with a compression space and an installation space which is arranged on the opposite side of the compression space and is connected with the compression space. A pair of star rotors are rotatably installed in the corresponding installation spaces. A bearing assembly is arranged at the upper end of the main rotor, and a shaft seal pressure reducing assembly as described in the above scheme is arranged at the lower end, so that the main rotor can be rotatably supported on the casing.

[0018] As a further improvement of the present invention, the casing is provided with an oil-passing groove on the inner wall surface of the lower port of the compression space, the upper housing is mounted on the lower port to seal the notch of the oil-passing groove to form a shaft seal oil chamber, and the two radial ends of the oil-passing groove are respectively provided with openings;

[0019] The casing is provided with an air inlet, an oil inlet, a main oil circuit, a second branch oil circuit and an oil and gas outlet.

[0020] The shaft seal oil chamber connects the main oil circuit with the second branch oil circuit through two openings thereon. The main oil circuit is connected to the oil inlet and has an oil supply path for synchronously delivering the lubricating oil to the compression space, the shaft seal oil chamber and the first branch oil circuit; the second branch oil circuit is used to deliver the lubricating oil entering the shaft seal oil chamber from the main oil circuit to the compression space; at the same time, the air sucked into the compression space by the air inlet and the lubricating oil entering the compression space from the main oil circuit and the second branch oil circuit are compressed and uniformly discharged from the casing from the oil and gas outlet.

[0021] As a further improvement of the present invention, the bearing assembly includes a bearing seat installed at the upper port of the compression space, a second bearing arranged on the bearing seat and fixedly connected to the upper end of the main rotor, and a bearing cover arranged on the bearing seat and positioning the second bearing in the bearing seat;

[0022] The air inlet is arranged close to a side of the bearing assembly;

[0023] An adjusting gasket is arranged between the upper flange of the upper shell and the casing.

[0024] As a further improvement of the present invention, the oil-gas outlet is a triangular outlet opened on one side of the compression space, the housing is provided with an oil-gas cavity for conveying an oil-gas mixed fluid, the outlet of the oil-gas cavity is provided on the opposite side of the oil inlet of the housing, and a one-way valve assembly is installed at the outlet of the oil-gas cavity;

[0025] The one-way valve assembly comprises:

[0026] A valve body, mounted at the outlet of the oil-gas chamber, and provided with an exhaust port;

[0027] A valve stem, elastically arranged on the valve body, having a plug arranged on one side of the outlet of the oil-gas chamber;

[0028] The spring is sleeved on the valve stem, and two ends of the spring are elastically abutted against the valve body and the plug respectively.

[0029] As a further improvement of the present invention, the oil inlet is further provided with two oil supply pipes, and the two oil supply pipes are respectively connected to the two star rotors.

[0030] The beneficial effects of the present invention are as follows: a shaft seal oil chamber is provided between the casing and the shaft seal pressure reducing assembly to ensure the sealing of the connection between the main rotor and the casing, thereby achieving the sealing of the compression space; a sealing component is provided in the shaft seal pressure reducing assembly together with a shaft seal oil circuit to ensure the sealing of the connection between the main rotor and the shaft seal pressure reducing assembly, and at the same time, an isolation ring is provided to prevent the lubricating oil from directly impacting the main rotor, thereby preventing the compressor from shaking, thereby increasing the service life of the main rotor and the sealing component. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a structural schematic diagram of a single screw air compressor of the present invention;

[0032] Figure 2 is a cross-sectional schematic diagram of the present invention at a first viewing angle;

[0033] Figure 3 is a cross-sectional schematic diagram of the present invention at a second viewing angle;

[0034] Figure 4 For the present invention Figure 2 A schematic diagram of the enlarged structure at point A;

[0035] Figure 5 This is a schematic diagram of the isolation ring structure of the present invention;

[0036] Figure 6 It is a structural schematic diagram of the present invention from a third viewing angle;

[0037] Figure 7 For the present invention Figure 6 A schematic cross-sectional view of the BB direction;

[0038] Figure 8 This is a schematic diagram of the casing structure of the present invention;

[0039] Fig. 9 This is a schematic diagram of the casing of the present invention with a portion of the casing cut away from its lower port upwards to show the internal details.

[0040] Combined with the accompanying drawings, the following description is given:

[0041] 10. Main rotor; 101. Spiral groove; 102. Screw shaft; 20. Bearing assembly; 201. Bearing seat; 202. Second bearing; 203. Bearing cover; 30. Casing; 301. Compression space; 302. Placement space; 303. Oil groove; 3031. Through port; 304. Shaft seal oil chamber; 305. Air inlet; 306. Oil inlet; 3061. Oil supply pipe; 307. Main oil circuit; 308. Second branch oil circuit; 309. Oil and gas outlet; 40. Shaft seal pressure relief assembly; 41. Upper housing; 411. First branch oil circuit; 412. Upper flange; 42. Lower housing; 421. Shaft seal oil circuit; 422. Groove; 4221. Horizontal part; 4222, inclined portion; 423, lower flange; 424, mounting groove; 425, abutment surface; 426, supporting surface; 427, plug-in portion; 43, first space; 44, rotating component; 441, first bearing; 442, bushing; 443, fixing member; 45, sealing component; 451, moving ring; 452, stationary ring; 453, isolating ring; 4531, notch; 4532, top end surface; 46, decompression chamber; 47, perforation; 50, star rotor; 501, teeth; 502, rotor shaft; 60, adjusting gasket; 70, one-way valve assembly; 701, valve body; 7011, exhaust port; 702, valve stem; 7021, plug; 703, spring. DETAILED DESCRIPTION

[0042] A preferred embodiment of the present invention is described in detail below in conjunction with the accompanying drawings.

[0043] See also Figure 1 , reference numeral 100 represents an exemplary embodiment of a single-screw air compressor, and it includes a shaft seal pressure reducing assembly 40 according to an embodiment of the present disclosure. The single-screw air compressor 100 generally includes a casing 30, a main rotor 10 installed to rotate in the casing 30, and a pair of star rotors 50 installed to rotate in the casing 30 and engaged with the main rotor 10.

[0044] See also Figures 1 to 9 The casing 30 of the compressor includes a compression space 301 in the form of a cylindrical hole, in which the main rotor 10 is rotatably mounted. The cylindrical hole is provided with an air inlet 305 at its suction end and is closed by a discharge end wall. The main rotor 10 is substantially cylindrical and has a plurality of spiral grooves 101 provided thereon to define a compression chamber, and the main rotor 10 is provided with a screw shaft 102, the opposite ends of which are rotatably supported on a bearing assembly 20 and a shaft seal pressure reducing assembly 40 mounted on the casing 30. The screw shaft 102 drives the main rotor 10 to rotate about its axis.

[0045] The housing 30 is further provided with a placement space 302 in communication with the compression space 301 on the opposite side thereof, and a pair of star rotors 50 are respectively installed in the corresponding placement spaces 302, so that the star rotors 50 are placed on the opposite sides of the main rotor 10 (i.e., 180 degrees apart). Each star rotor 50 has a plurality of teeth 501 and is provided with a rotor shaft 502, the opposite ends of which are rotatably mounted on the housing 30 through bearing units. When the main rotor 10 is rotatably driven by a driving source such as a motor (not shown), the teeth 501 in the star rotor 50 successively engage the spiral grooves 101 of the main rotor 10, and cooperate with the wall of the compression space 301 to define a compression chamber. An air inlet 305 is provided at the upper end of the compression chamber (i.e., near the starting end of the spiral groove 101). Air is sucked into the compression chamber through the air inlet 305 and compressed through the relative movement of the meshing spiral groove 101 and the tooth 501, and discharged from the triangular oil and gas outlet 309 opened on the wall of the compression space of the casing 30 near the end of the spiral groove 101. The casing 30 is provided with a lubricating oil inlet 306 and a main oil circuit 307 communicating with the oil inlet 306. The main oil circuit 307 is used to transport lubricating oil to the compression space 301 to lubricate, cool and seal the components in the compression space. The oil inlet 306 is also provided with two oil supply pipes 3061, which are respectively connected to the two placement spaces 302 and docked with the bearing unit on which the star rotor 50 is installed to cool and lubricate the bearing unit. In addition, the housing 30 is provided with an oil-gas chamber for conveying an oil-gas mixed fluid. Similar to the prior art, the oil-gas chamber is arranged as a maze structure, with the difference that: the outlet of the oil-gas chamber is arranged on the opposite side of the oil inlet 306 of the housing 30, and a one-way valve assembly 70 is installed at the outlet of the oil-gas chamber; the one-way valve assembly 70 includes a valve body 701, a valve stem 702 and a spring 703 sleeved on the valve stem 702, the valve body 701 is installed at the outlet of the oil-gas chamber, and an exhaust port 7011 connected to an external oil-gas separation device is provided on the valve body 701; the valve stem 702 is elastically arranged on the valve body 701, and has a plug 7021 arranged on the outlet side of the oil-gas chamber; the two ends of the spring 703 are elastically abutted against the valve body 701 and the plug 7021 respectively. Under the combined action of the spring 703 and the compressed oil and gas pressure, the plug 7021 can elastically reciprocate along the axial direction of the valve stem 702 to open or close the outlet of the oil and gas chamber, thereby achieving the compressed oil and gas being output from the compressor and preventing backflow after the compressor is shut down, thereby avoiding damage to the compressor.

[0046] See also Figures 1 to 5Compared with the prior art, the opposite ends of the main rotor 10 of the embodiment of the present disclosure are rotatably supported on the housing 30 through the bearing assembly 20 and the shaft seal decompression assembly 40 respectively. Among them, the bearing assembly 20 is a modular structure, including a bearing seat 201 installed on the upper port of the compression space 301, a second bearing 202 arranged on the bearing seat 201 and fixedly connected to the upper end of the main rotor 10, and a bearing cover 203 covered on the bearing seat 201; the bearing seat 201 and the bearing cover 203 are spliced ​​and installed on the housing 30 through the flanges thereon to rotatably position the upper end of the main rotor 10. The air inlet 305 is arranged close to one side of the bearing assembly 20 so that the inhaled air enters the compression space from the starting end of the spiral groove 101 of the main rotor 10. The other end of the main rotor 10 connected to the housing 30 is rotatably positioned by the shaft seal decompression assembly 40. Specifically, air (i.e., low-pressure air) is sucked into the compression space 301 from the air inlet 305, compressed into high pressure and discharged from the oil and gas outlet 309, that is, the axial force of the rotating main rotor 10 gradually increases from its upper end (low-pressure air inlet) to the lower end (high-pressure air outlet). The difference in axial force between the upper and lower ends is more obvious in the high-pressure compressor. The difference in axial force affects the rotation of the main rotor 10, which manifests as the jitter of the compressor. The jitter of the compressor will affect the sealing of the connection between the main rotor 10 and the shaft seal pressure reducing assembly 40, as well as the sealing between the shaft seal pressure reducing assembly 40 and the casing 30, and will also affect the service life of the main rotor and the sealing of the compression chamber.

[0047] Based on this, see Figures 2 to 5 , the embodiment of the present disclosure provides a shaft seal decompression assembly 40, which includes an upper shell 41, a lower shell 42 arranged at the lower side of the upper shell 41 and plugged with the upper shell 41 to form a first space 43, and a rotating component 44 and a sealing component 45 arranged in the first space 43 and arranged in sequence from top to bottom along the axial direction of the main rotor 10; the main rotor 10 passes through the shaft seal decompression assembly 40 along its axial direction and is connected to the driving source, that is, the motor (not shown). Specifically, the shaft seal decompression assembly 40 is a modular structure, and an adjusting gasket 60 is arranged between it and the casing 30. By replacing the adjusting gasket 60 with different thicknesses, the axial gap between the main rotor 10 and the casing 30 is adjusted, so that the main rotor 10 reaches the optimal installation state. In addition, since the bearing assembly 20 and the shaft seal decompression assembly 40 are both modular structures, it is convenient to install and disassemble the main rotor.

[0048] The upper shell 41 of the disclosed embodiment is provided with a first branch oil circuit 411 connected to the main oil circuit 307, and the lower shell 42 is provided with a shaft seal oil circuit 421 for connecting the first branch oil circuit 411 with the first space 43, so that the lubricating oil can enter the first space 43 to seal, cool and lubricate the components placed in the first space 43. Moreover, the lubricating oil of the present embodiment enters the first space 43 through the oil inlet 306 to the main oil circuit 307 and then enters the first space 43 through the first branch oil circuit 411 and the shaft seal oil circuit 421. The oil supply paths are all arranged on the compressor, and no special oil supply system is set. The design is ingenious and reasonable, and the overall circulation oil supply of various parts of the compressor is realized.

[0049] A groove 422 is formed on the inner circumferential wall of the lower shell 42, and the outlet of the shaft seal oil circuit 421 is placed on the groove 422; the sealing component 45 is arranged on the lower shell 42, including a dynamic ring 451 and a static ring 452 which are sequentially sleeved on the main rotor 10 from top to bottom, and an isolation ring 453 which is arranged outside the dynamic ring 451 and installed on the lower shell 42; the isolation ring 453 closes the notch of the groove 422 to form a decompression chamber 46, and a notch 4531 is opened on the isolation ring 453 to connect the decompression chamber 46 with the first space 43. That is, the isolation ring 453 is fixedly installed in the lower shell 42, and its inner ring surface and the outer ring surface of the dynamic ring 451 have a certain gap. Therefore, when the high-pressure oil is injected into the first space 43, due to the stopper of the isolation ring 453 and the setting of the gap, the lubricating oil will not impact the rotating main rotor, avoiding the shaking due to the unequal axial force generated on the circumferential surface, thereby ensuring the lubrication, cooling and sealing effects of the main rotor 10 and the shaft seal pressure reducing assembly 40.

[0050] The dynamic ring 451 is fixedly connected to the main rotor 10 and can rotate with the main rotor 10. The static ring 452 is sealed and fixedly connected to the lower shell 42 and has a clearance fit with the main rotor 10, that is, the static ring 452 does not rotate with the main rotor 10. The main rotor 10 rotates so that the lubricating oil forms an oil film between the outer circumference of the main rotor 10 and the inner circumference of the static ring 452, and the oil film is used to achieve sealing and lubrication. Specifically, the lower side wall of the groove 422 is composed of a horizontal portion 4221 and an inclined portion 4222 which are arranged in sequence from the bottom of the groove to the inside along the radial direction of the main rotor 10. The inclined portion 4222 is arranged to be inclined from the outside to the inside and downward. One side of the lower end face of the isolation ring 453 has six notches 4531 in an axial annular array around it. The top end face 4532 of the notch 4531 is inclined from the inside to the outside and upward at a set angle. The inclination angle is 60°, and the starting end of the top end face 4532 is on the same horizontal plane as the horizontal portion 4221. Therefore, even if the lubricating oil enters the first space 43, it still has pressure. The notches 4531 arranged at 60° intervals and the structural design of the lower side wall of the groove 422 reduce the pressure of the lubricating oil entering the first space 43 and can act symmetrically on the rotating dynamic ring, thereby avoiding the shaking of the main rotor, extending the service life of the main rotor, and also extending the service life of the sealing component 45.

[0051] Furthermore, an upper flange 412 is provided on the outer edge of the upper shell 41 facing the lower shell 42 in a radially outward manner, and the lower shell 42 has a lower flange 423 connected to the upper flange 412. The first branch oil circuit 411 is arranged on the upper flange 412, and the shaft seal oil circuit 421 is arranged on the lower flange 423; an end of the lower shell 42 close to the upper through hole 47 is provided with a mounting groove 424 for mounting a stationary ring 452, and the axial cross-section of the stationary ring 452 is in the shape of a "7", and its inner circumferential wall is annularly sleeved on the main rotor 10, and the top surface extends the mounting groove 424 upward and slides against the lower end surface of the moving ring 451, and an oil film is generated between the end surfaces to reduce friction.

[0052] The inner wall of the lower shell 42 is formed with abutment surfaces 425 that are adapted to the outer wall of the isolation ring 453 on the upper and lower sides of the groove 422. The lower end of the abutment surface 425 is connected to the notch of the installation groove 424 through a horizontal supporting surface 426. The lower end surface of the isolation ring 453 abuts on the supporting surface 426 to ensure the stable installation of the isolation ring 453 and the lower shell 42.

[0053] The lower housing 42 further includes a plug-in portion 427 plugged into the upper housing 41, and the upper end surface of the plug-in portion 427 presses the outer ring of the first bearing 441 against the upper housing 41; the rotating component 44 further includes a sleeve 442 and a fixing member 443 respectively disposed at the upper and lower ends of the first bearing 441, and the sleeve 442 and the fixing member 443 are both fixedly attached to the main rotor 10, so as to position the inner ring of the first bearing 441 on the main rotor 10 and rotate with the main rotor 10, and the sleeve 442 is also inserted into the through hole 47 of the upper housing 41 and slidably connected to the through hole 47. In addition, the first bearing 441 adopts a double ball bearing to withstand a large axial force.

[0054] See also Figures 3 to 9 In order to ensure the sealing between the shaft seal pressure reducing assembly 40 and the casing 30, the casing 30 is provided with an oil passing groove 303 on the inner wall surface of the lower port of the compression space 301, and the upper shell 41 is installed on the lower port to close the notch of the oil passing groove 303 to form a shaft seal oil chamber 304, and the two radial ends of the oil passing groove 303 are respectively provided with through openings 3031; the shaft seal oil chamber 304 connects the main oil circuit 307 and the second branch oil circuit 308 through the two through openings 3031. That is, the lubricating oil of this embodiment enters the main oil circuit 307 from the oil inlet 306, and is synchronously transported to the compression space 301, the shaft seal oil chamber 304 and the first branch oil circuit 411 through the main oil circuit 307; and the second branch oil circuit 308 is used to transport the lubricating oil entering the shaft seal oil chamber 304 from the main oil circuit 307 to the compression space 301, so as to realize the circulation of the lubricating oil; at the same time, the air sucked into the compression space 301 from the air inlet 305 and the lubricating oil entering the compression space 301 from the main oil circuit 307 and the second branch oil circuit 308 are compressed and uniformly discharged from the casing 30 from the oil and gas outlet 309. That is, the lubricating oil of this embodiment is divided into four paths after entering the compressor: one path enters the star rotors on both sides through the oil supply pipe 3061, and the other three paths refer to the attached Figure 7 The arrows indicate the flow direction, one of which goes directly into the compression space through the main oil circuit 307, the other goes through the shaft seal oil chamber 304 and the second branch oil circuit 308 in sequence to enter the compression space, and the last goes through the first branch oil circuit 411, the shaft seal oil circuit 421, and the notch 4531 in sequence to enter the first space 43, so that the oil supply is integrated, the structure is simple, and the oil circuit is clear, so as to achieve sealing, cooling and lubrication between the components.

[0055] In summary, the shaft seal pressure reducing assembly and the single-screw air compressor using the shaft seal pressure reducing assembly provided by the present invention ensure the sealing of the connection between the main rotor and the casing by setting a shaft seal oil chamber between the casing and the shaft seal pressure reducing assembly, thereby realizing the sealing of the compression space; and ensure the sealing of the connection between the main rotor and the shaft seal pressure reducing assembly by setting a sealing component and a shaft seal oil circuit in the shaft seal pressure reducing assembly. At the same time, an isolation ring is used to prevent the lubricating oil from directly impacting the main rotor, thereby preventing the compressor from shaking, thereby improving the service life of the main rotor and the sealing component.

[0056] Many specific details are described in the above description to facilitate a full understanding of the present invention. However, the above description is only a preferred embodiment of the present invention. The present invention can be implemented in many other ways different from those described herein, so the present invention is not limited to the specific implementation disclosed above. At the same time, any person familiar with the art can make many possible changes and modifications to the technical solution of the present invention using the methods and technical contents disclosed above without departing from the scope of the technical solution of the present invention, or modify it into an equivalent embodiment of equivalent changes. Any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention without departing from the content of the technical solution of the present invention still falls within the scope of protection of the technical solution of the present invention.

Claims

1. A shaft seal pressure reducing assembly, arranged on a side of a main rotor (10) of a single screw air compressor near a lower end, and used together with a bearing assembly (20) at an upper end of the main rotor (10) to rotatably support the main rotor (10) on a casing (30) of the compressor, characterized in that: The shaft seal decompression assembly (40) comprises an upper shell (41) arranged on the housing (30), a lower shell (42) arranged on the lower side of the upper shell (41) and plugged with the upper shell (41) to form a first space (43), and a rotating component (44) and a sealing component (45) arranged in the first space (43) and arranged in sequence from top to bottom along the axial direction of the main rotor (10); the main rotor (10) passes through the shaft seal decompression assembly (40) along its axial direction to be connected to a driving source; The upper housing (41) is provided with a first branch oil path (411) communicating with the compressor oil supply system, and the rotating component (44) comprises a first bearing (441) mounted on the upper housing (41) and sleeved on the main rotor (10); The lower housing (42) is provided with a shaft seal oil passage (421) for connecting the first branch oil passage (411) with the first space (43); a groove (422) is provided on the inner peripheral wall of the lower housing (42); and an outlet of the shaft seal oil passage (421) is disposed on the groove (422); The sealing component (45) is arranged on the lower housing (42), and comprises a moving ring (451) and a stationary ring (452) which are sequentially sleeved on the main rotor (10) from top to bottom, and an isolating ring (453) which is arranged outside the moving ring (451) and mounted on the lower housing (42); the moving ring (451) is fixedly connected to the main rotor (10) and can rotate with the main rotor (10), and the stationary ring (452) is sealed and fixedly connected to the lower housing (42) and is clearance-matched with the main rotor (10); The isolating ring (453) closes the notch of the groove (422) to form a decompression chamber (46), and the isolating ring (453) is provided with a notch (4531) for connecting the decompression chamber (46) and the first space (43); The lower side wall of the groove (422) is composed of a horizontal portion (4221) and an inclined portion (4222) which are arranged in sequence from the groove bottom to the inner side along the radial direction of the main rotor (10); the inclined portion (4222) is arranged to be inclined downward from the outside to the inside; one side of the lower end surface of the isolation ring (453) is provided with six notches (4531) in an annular array around the axial direction; the top end surface (4532) of the notch (4531) is arranged to be inclined upward from the inside to the outside at a set angle, and the starting end of the top end surface (4532) is on the same horizontal plane as the horizontal portion (4221); The upper shell (41) and the lower shell (42) are both provided with a through hole (47) for the main rotor (10) to pass through; an outer edge of the upper shell (41) facing the lower shell (42) is provided with an upper flange (412) protruding outwardly along its radial direction; the lower shell (42) has a lower flange (423) butted against the upper flange (412); the first branch oil path (411) is arranged on the upper flange (412); and the shaft seal oil path (421) is arranged on the lower flange (423); An installation groove (424) for installing the stationary ring (452) is provided at one end of the lower shell (42) close to the through hole (47) thereon. The axial cross-section of the stationary ring (452) is in the shape of a letter "7". Its inner peripheral wall is annularly sleeved on the main rotor (10). The top surface extends upward from the installation groove (424) and is in sliding contact with the lower end surface of the moving ring (451).

2. The shaft seal pressure reducing assembly according to claim 1, characterized in that: The inner circumferential wall of the lower shell (42) is provided with abutment surfaces (425) respectively formed on the upper and lower sides of the groove (422) and adapted to the outer circumferential wall of the isolation ring (453); the lower end of the abutment surface (425) is connected to the notch of the installation groove (424) via a horizontal supporting surface (426), and the lower end surface of the isolation ring (453) abuts against the supporting surface (426).

3. The shaft seal pressure reducing assembly according to claim 2, characterized in that: The lower housing (42) further comprises an inserting portion (427) inserted into the upper housing (41), and the upper end surface of the inserting portion (427) positions the outer ring of the first bearing (441) in the upper housing (41); The rotating component (44) further comprises a shaft sleeve (442) and a fixing member (443) respectively arranged at the upper and lower ends of the first bearing (441); the shaft sleeve (442) and the fixing member (443) are both fixedly attached to the main rotor (10) so as to position the inner ring of the first bearing (441) on the main rotor (10) and rotate together with the main rotor (10); and the shaft sleeve (442) is also inserted into a through hole (47) of the upper shell (41) and is slidably connected to the through hole (47).

4. A single screw air compressor, characterized in that: It comprises a casing (30), a main rotor (10) provided on the casing (30), and a pair of star rotors (50) provided on the casing (30) and arranged on opposite sides of the main rotor (10); The casing (30) has a compression space (301) and an accommodation space (302) arranged on the opposite side of the compression space (301) and connected to the compression space (301), and a pair of star rotors (50) are rotatably installed in the corresponding accommodation spaces (302). The upper end of the main rotor (10) is provided with a bearing assembly (20), and the lower end is provided with a shaft seal pressure reducing assembly (40) as described in any one of claims 1 to 3, so that the main rotor (10) can be rotatably supported on the casing (30).

5. The single screw air compressor according to claim 4, characterized in that: The casing (30) is provided with an oil-passing groove (303) on the inner wall surface of the lower port of the compression space (301); the upper casing (41) is mounted on the lower port to seal the notch of the oil-passing groove (303) to form a shaft seal oil chamber (304); and the two radial ends of the oil-passing groove (303) are respectively provided with openings (3031); The housing (30) is provided with an air inlet (305), an oil inlet (306), a main oil circuit (307), a second branch oil circuit (308) and an oil and gas outlet (309); The shaft seal oil chamber (304) communicates with the main oil circuit (307) and the second branch oil circuit (308) through two openings (3031) thereon; the main oil circuit (307) is communicated with the oil inlet (306) and has an oil supply path for synchronously conveying lubricating oil to the compression space (301), the shaft seal oil chamber (304) and the first branch oil circuit (411); the second branch oil circuit (308) is used to convey lubricating oil entering the shaft seal oil chamber (304) from the main oil circuit (307) to the compression space (301); at the same time, the air sucked into the compression space (301) through the air inlet (305) and the lubricating oil entering the compression space (301) from the main oil circuit (307) and the second branch oil circuit (308) are compressed and uniformly discharged from the casing (30) through the oil and gas outlet (309).

6. The single screw air compressor according to claim 5, characterized in that: The bearing assembly (20) comprises a bearing seat (201) mounted on an upper port of the compression space (301), a second bearing (202) disposed on the bearing seat (201) and fixedly connected to an upper end of the main rotor (10), and a bearing cover (203) disposed on the bearing seat (201) and positioning the second bearing (202) in the bearing seat (201); The air inlet (305) is arranged close to a side of the bearing assembly (20); An adjusting gasket (60) is provided between the upper flange (412) of the upper shell (41) and the casing (30).

7. The single screw air compressor according to claim 6, characterized in that: The oil-gas outlet (309) is a triangular outlet opened on one side of the compression space (301); the housing (30) is provided with an oil-gas chamber for conveying an oil-gas mixed fluid; the outlet of the oil-gas chamber is provided on the opposite side of the oil inlet (306) of the housing (30); and a one-way valve assembly (70) is installed at the outlet of the oil-gas chamber; The one-way valve assembly (70) comprises: A valve body (701) is installed at the outlet of the oil-gas chamber and is provided with an exhaust port (7011); A valve stem (702) is elastically arranged on the valve body (701) and has a plug (7021) arranged on one side of the outlet of the oil-gas chamber; The spring (703) is sleeved on the valve stem (702), and two ends of the spring are elastically abutted against the valve body (701) and the plug (7021) respectively.

8. The single screw air compressor according to claim 7, characterized in that: The oil inlet (306) is further provided with two oil supply pipes (3061), and the two oil supply pipes (3061) are respectively connected to the two star rotors (50).

Images