Screw air compressor

Abstract

The utility model discloses a screw air compressor, including the shaft with the tooth part and the casing with the cavity, the shaft is along its axial and is placed in the cavity, and the axial both ends are through bearing assembly and casing rotatable connection respectively, still include the shaft sealing assembly, and the both ends of shaft pass through two groups of shaft sealing assembly and the bearing of bearing assembly's connection to make the bearing seal in the bearing seat of bearing assembly. The utility model discloses a bearing assembly and the shaft between setting up the shaft sealing assembly, to realize the isolation between bearing and casing, prevent gas, liquid and enter the bearing to influence the service life of bearing, through the elastic abutment sealing of dynamic sealing unit and static sealing unit and the centrifugal drainage effect of centrifugal piece, realize multistage sealing, to ensure the working environment of bearing, prolong the bearing life, improve the reliability and stability of compressor.

Description

Technical Field

[0001] This utility model relates to the field of air compressor technology, specifically to a screw air compressor. Background Technology

[0002] A single-screw air compressor consists of a cylindrical screw and two symmetrically arranged planar star wheels forming a meshing pair, housed within a main casing. The space enclosed by the screw grooves, the inner wall of the main casing, and the tooth surfaces of the star wheels constitutes the compressor's working volume. The motor directly drives the screw shaft to rotate, which in turn drives the star wheels. Gas enters the screw grooves through the intake port on the main unit, is compressed, and then exits through the exhaust port on the main casing. During operation, lubricating fluid is injected through the injection holes in the main casing, serving sealing, cooling, and lubrication purposes. In industries with high hygiene requirements, such as food and medical, water is often used as a lubricating fluid. However, water has low viscosity and high fluidity; if the compressor's sealing structure is inadequate, lubricating water can easily enter the bearings, damaging the lubricating oil film, accelerating wear, leading to bearing damage, and affecting the compressor's lifespan. Summary of the Invention

[0003] To overcome the above-mentioned defects, this utility model provides a screw air compressor that improves the sealing performance of the screw air compressor in water lubrication scenarios and extends the bearing life.

[0004] The technical solution adopted by this utility model to solve its technical problem is: to provide a screw air compressor, including a toothed shaft and a housing with a cavity, the shaft passing through the cavity along its axial direction, and the two ends of the shaft being rotatably connected to the housing through bearing assemblies, and also including a shaft sealing assembly, the two ends of the shaft passing through two sets of shaft sealing assemblies and being connected to the bearings of the bearing assembly, so that the bearings are sealed in the bearing seats of the bearing assembly.

[0005] As a further improvement of this utility model, the bearing assembly includes a bearing seat disposed on the housing, and the first end of the bearing seat extends into the cavity; The shaft seal assembly includes: A dynamic sealing unit, disposed on the shaft and rotating with the shaft, includes a dynamic sealing ring fixedly mounted on the tooth end face; A static sealing unit is annularly disposed on the shaft and fixedly installed on the end face of the first end, including a static sealing ring disposed opposite to the dynamic sealing ring. The static sealing ring is configured to elastically abut against the dynamic sealing ring so that an annular space is formed between the bearing housing and the shaft. The bearing housing has multiple outlets on its peripheral wall that connect the annular space to the outside.

[0006] As a further improvement of this utility model, the dynamic sealing unit also includes a dynamic connector, which is fitted onto the shaft and fixedly connected to the toothed part. A mounting groove for accommodating the dynamic sealing ring is formed on the side end face of the dynamic connector away from the toothed part. The static sealing unit further includes a static connector, which is circumferentially disposed on the shaft and fixed to the first end of the bearing housing. Multiple springs are provided between the static sealing ring and the static connector. The multiple springs are arranged in a ring array around the shaft, and the two ends of each spring elastically abut against the relatively close end faces of the static sealing ring and the static connector.

[0007] As a further improvement of this utility model, the static sealing ring is made into a stepped shape, and the width of its contact surface with the dynamic sealing ring is 1 / 2 of the diameter of the end face of the dynamic sealing ring.

[0008] As a further improvement of this utility model, the static connector is connected to the first end of the bearing seat through a water seal cover. The water seal cover includes a connecting part fixed to the first end and a blocking part extending toward the cavity and surrounding the outer wall of the moving connector. A gap is provided between the inner wall surface of the blocking part and the outer wall surface of the moving connector.

[0009] As a further improvement of this utility model, the shaft sealing assembly further includes a centrifugal element sleeved on the shaft and rotating with the shaft, the centrifugal element being located between the bearing and the moving connection; The centrifugal component includes a first optical axis portion, a second optical axis portion, and a grid portion integrally connected between the first optical axis portion and the second optical axis portion. The end face of the first optical axis portion is sealed to the end face of the inner ring of the bearing and is clearance-fitted with the bearing seat. The second optical axis portion is sealed to the dynamic connecting member and is clearance-fitted with the static sealing unit. The grid section is located in the annular space and is composed of a plurality of centrifugal blades arranged at equal intervals along the axial direction of the centrifugal element.

[0010] As a further improvement of this utility model, the shaft sealing assembly further includes a sealing sleeve, which is fixed by the bearing seat and slidably sealed to the first optical shaft portion; The sealing sleeve stops at one end face of the bearing and extends radially inward from the outer ring of the bearing to abut against the first optical axis portion.

[0011] As a further improvement of this utility model, a plurality of trapezoidal grooves are provided at equal intervals along the axial direction on the inner peripheral wall of the sealing sleeve that slides with the first optical axis portion.

[0012] As a further improvement of this utility model, the bearing assembly also includes a bearing cover, and the two bearing covers are respectively disposed on the two bearing seats; One end of the shaft passes through the bearing cap at the corresponding end and connects to the drive source.

[0013] As a further improvement of this utility model, a sliding sealing structure is provided between the bearing cover facing the drive source end and the shaft. The sliding sealing structure includes a spacer, a fixing nut and a dustproof ring, which are sleeved on the shaft and arranged sequentially from the inside to the outside along the axial direction. The spacer sleeve is pressed against the bearing by the fixing nut and rotates with the shaft. At the same time, the spacer sleeve is slidably sealed to the bearing seat at the corresponding end. The dustproof ring is fixedly connected to the bearing cap at the corresponding end and slides with the shaft.

[0014] The beneficial effects of this utility model are: by setting a shaft sealing assembly between the bearing assembly and the shaft, the bearing and the housing are isolated to prevent gas and liquid from entering the bearing and affecting its service life; through the elastic contact sealing of the dynamic sealing unit and the static sealing unit, and the centrifugal drainage effect of the centrifugal component, multi-stage sealing is achieved to ensure the working environment of the bearing, extend the bearing life, and improve the reliability and stability of the compressor. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the structure of this utility model; Figure 2 This utility model Figure 1 A schematic diagram of the cross-section along the FF direction; Figure 3 This utility model Figure 2 Enlarged view of point A; Figure 4 This utility model Figure 2 Enlarged diagram of point B.

[0016] Referring to the accompanying drawings, the following explanations are provided: 1. Shaft; 101. Gear; 2. Housing; 201. Cavity; 3. Bearing assembly; 301. Bearing; 302. Bearing seat; 3021. First end; 3022. Outlet; 303. Bearing cover; 4. Shaft sealing assembly; 40. Dynamic sealing unit; 401. Dynamic sealing ring; 402. Dynamic connecting part; 4021. Mounting groove; 41. Static sealing unit; 411. Static sealing ring; 412. Static connecting part; 413. Spring; 414. Water sealing cover; 4140. Connecting part; 4141. Blocking part; 415. Centrifugal component; 4150. First optical shaft part; 4151. Second optical shaft part; 4152. Grid part; 416. Sealing sleeve; 4160. Trapezoidal groove; 5. Annular space; 6. Sliding sealing structure; 601. Spacer; 602. Fixing nut; 603. Dustproof ring. Detailed Implementation

[0017] The preferred embodiment of the present invention will be described in detail below with reference to the accompanying drawings.

[0018] Existing screw air compressors mainly consist of a casing, a shaft rotatably mounted within the casing, and a pair of star-shaped rotors coupled to the shaft and also rotating within the casing. It should be noted that the specific structure and air compression principle of screw air compressors fall within the scope of existing technology and are not the inventive point of this application; therefore, they will not be elaborated upon here. Given that this application uses water as the lubrication and cooling medium, the inventive point of this application lies in the bearing sealing design. Specifically, by setting the shaft sealing assembly 4, the bearing is effectively isolated from the compression chamber, thereby preventing water or water mist from the compression chamber from seeping into the bearing and ensuring the bearing's service life.

[0019] See Figures 1 to 4 Compared with the prior art, the opposite ends of the shaft 1 provided in this application are rotatably supported on the housing 2 by the shaft sealing assembly 4 and the bearing assembly 3, respectively. Figure 2 For reference, the shaft seal assembly 4 and bearing assembly 3 located at the upper end will be described.

[0020] Regarding bearing assembly 3. The bearing assembly 3 is a modular structure, including a bearing housing 302 installed on the upper port of the cavity 201, a bearing 301 disposed on the bearing housing 302 and fixedly connected to the upper end of the shaft 1, and a bearing cover 303 covering the bearing housing 302; the bearing housing 302 and the bearing cover 303 are spliced ​​together by flanges and installed on the housing 2 to rotatably position the shaft 1.

[0021] It should be noted that the bearing assembly installed at the lower port of the housing differs structurally from the bearing assembly located at the upper port of the housing. Specifically, the bearing cover of the lower port bearing assembly has a through hole for the shaft to pass through. After the shaft passes through this hole, it is connected to the drive source (such as a motor) to drive the shaft to rotate.

[0022] Given the structural characteristics of the lower bearing assembly, a sliding seal structure 6 is provided at the connection between the bearing cover and the shaft to prevent external contaminants from entering the bearing. The sliding seal structure 6 includes a spacer 601, a fixing nut 602, and a dust seal ring 603, which are sequentially arranged axially from the inside to the outside and fitted onto the shaft 1. The spacer 601 is pressed against the bearing 301 by the fixing nut 602 and rotates synchronously with the shaft 1. Simultaneously, the spacer 601 is slidably sealed to the bearing housing 302, meaning that the spacer 601 does not affect the rotation of the shaft while simultaneously forming a dynamic seal with the bearing housing. The dust seal ring 603 is fixed inside the hole of the bearing cover 303 and slides against the shaft 1, thus forming a dynamic seal between the shaft and the bearing cover, further preventing external dust and contaminants from entering the bearing housing and contacting the bearing. Furthermore, this sliding seal structure 6 reduces vibration and noise between the shaft and the bearing assembly, ensuring stable compressor operation and extending the compressor's service life.

[0023] To achieve dynamic sealing, the following structure can be used: A sealing ring is placed on the circumferential surface of the relatively stationary component in one of the two mating parts. When the circumferential surface of the moving component rotates, it will form sliding contact with the stationary sealing ring. This achieves a sealing effect without hindering the rotation of the moving component.

[0024] Regarding shaft seal assembly 4.

[0025] The shaft sealing assembly 4 includes a dynamic sealing unit 40 and a static sealing unit 41 arranged axially opposite to each other. The dynamic sealing unit 40 is sleeved on the shaft 1 and rotates synchronously with the shaft 1. The dynamic sealing unit 40 includes a dynamic connector 402, which is sleeved on the shaft 1 and fixedly connected to the toothed portion 101. A mounting groove 4021 for accommodating the dynamic sealing ring 401 is formed on the end face of the dynamic connector 402 opposite to the toothed portion 101, so that the dynamic sealing ring can be stably installed on the shaft and rotate with the shaft to achieve relative motion sealing with the static sealing ring. The static sealing unit 41 is annularly disposed on the shaft 1 and fixedly installed on the end face of the first end 3021 of the bearing housing. It includes a static sealing ring 411 arranged opposite to the dynamic sealing ring 401. The static sealing ring 411 is configured to elastically abut against the dynamic sealing ring 401 so that an annular space 5 is formed between the bearing housing 302 and the shaft 1. This annular space provides the necessary conditions for subsequent secondary sealing of the bearing. The contact-type dynamic sealing isolation is achieved by using a spring-loaded dynamic-static sealing ring, which is the primary sealing method in this embodiment.

[0026] The static sealing ring 411 and the dynamic sealing ring 401 are elastically abutted together. On the one hand, this ensures that the static sealing ring 411 and the dynamic sealing ring 401 remain tightly fitted, thereby ensuring the reliability of the seal and preventing the medium inside the cavity from entering the bearing housing. On the other hand, the elastic abutment will not cause excessive friction between the static sealing ring 411 and the rotating dynamic sealing ring 401, thus avoiding the normal rotation of the shaft 1 due to excessive friction and extending the seal life.

[0027] Specifically, the static sealing ring 411 is stepped, and the width of its contact surface with the dynamic sealing ring 401 is half the diameter of the end face of the dynamic sealing ring 401. This achieves sealing without affecting rotation. The stepped structure can distribute the sealing pressure to different surfaces, reduce local stress concentration, and extend the sealing life.

[0028] Furthermore, the static sealing unit 41 also includes a static connector 412, which is annularly disposed on the shaft 1 and fixed to the first end 3021 of the bearing housing 302. Multiple springs 413 are provided between the static sealing ring 411 and the static connector 412. These springs 413 are arranged in a ring array around the shaft 1, with each spring 413's two ends elastically abutting against the relatively close end faces of the static sealing ring 411 and the static connector 412. The function of the springs is to provide elastic pressure to the static sealing ring, ensuring it always maintains tight contact with the dynamic sealing ring and guaranteeing the reliability of the seal.

[0029] Furthermore, the stationary connector 412 is connected to the first end 3021 of the bearing housing 302 via a water seal 414. The water seal 414 includes a connecting portion 4140 fixed to the first end 3021 and a blocking portion 4141 extending toward the cavity 201 and surrounding the outer peripheral wall of the moving connector 402. A gap is provided between the inner wall surface of the blocking portion 4141 and the outer wall surface of the moving connector 402. The water seal serves to prevent liquid from splashing inside the cavity, preventing liquid from entering the annular space from the contact surface of the moving-stationary sealing ring. At the same time, the gap ensures the normal rotation of the shaft.

[0030] Furthermore, to prevent gas and liquid leakage when the dynamic-static sealing rings are not properly sealed, the shaft sealing assembly 4 also includes a centrifugal element 415 sleeved on the shaft 1 and rotating with the shaft. The centrifugal element 415 is located between the bearing 301 and the dynamic connector 402. The centrifugal element 415 includes a first optical shaft portion 4150, a second optical shaft portion 4151, and a grid portion 4152 integrally connected between the first optical shaft portion 4150 and the second optical shaft portion 4151. The end face of the first optical shaft portion 4150 is sealed to the end face of the inner ring of the bearing 301 and has a clearance fit with the bearing seat 302. The second optical shaft portion 4151 is sealed to the dynamic connector 402 and has a clearance fit with the static sealing unit 41. The grid portion 4152 is located in the annular space 5 and is composed of multiple centrifugal blades that are equidistantly spaced along the axial direction of the centrifugal element 415. When the shaft rotates, the centrifugal component rotates accordingly, causing the gas and liquid in the annular space to generate centrifugal force and be thrown out from the outlet 3022 on the bearing seat. The centrifugal liquid separation is the secondary seal.

[0031] Furthermore, the shaft sealing assembly 4 also includes a sealing sleeve 416, which is fixed by the bearing housing 302 and slidably sealed to the first optical shaft portion 4150. The sealing sleeve 416 stops at one end face of the bearing 301 and extends radially inward from the outer ring of the bearing 301 to the outer wall surface of the first optical shaft portion 4150, further preventing liquid generated during centrifugal washing from entering the bearing. Multiple trapezoidal grooves 4160 are equidistantly spaced axially on the inner peripheral wall where the sealing sleeve 416 and the first optical shaft portion 4150 slide together. These trapezoidal grooves reduce friction between the sealing sleeve and the first optical shaft portion without affecting the seal, thus improving sealing performance and service life.

[0032] In summary, the screw air compressor provided by this utility model achieves isolation between the bearing and the housing by setting a shaft sealing assembly between the bearing and the shaft, preventing gas and liquid from entering the bearing and affecting its service life. Through the elastic contact sealing of the dynamic-static sealing unit and the centrifugal drainage effect of the centrifugal components, sealing performance is ensured without interfering with the normal operation of other components, thus ensuring the bearing's working environment, extending bearing life, and improving the compressor's reliability and stability.

[0033] Many specific details have been set forth in the above description to provide a full understanding of this utility model. However, the above description is only a preferred embodiment of this utility model, and this utility model can be implemented in many other ways different from those described herein. Therefore, this utility model is not limited to the specific embodiments disclosed above. Furthermore, any person skilled in the art can make many possible variations and modifications to the technical solution of this utility model using the methods and techniques disclosed above, or modify it into equivalent embodiments with equivalent changes, without departing from the scope of the technical solution of this utility model. Any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of this utility model, without departing from the content of the technical solution of this utility model, shall still fall within the protection scope of the technical solution of this utility model.

Claims

1. A screw air compressor comprising a shaft (1) having teeth (101) and a housing (2) having a cavity (201), the shaft (1) passing through the cavity (201) along its axial direction, and both ends of the shaft (1) being rotatably connected to the housing (2) via bearing assemblies (3), characterized in that: It also includes a shaft seal assembly (4), with both ends of the shaft (1) passing through two sets of the shaft seal assemblies (4) and connected to the bearing (301) of the bearing assembly (3), so that the bearing (301) is sealed in the bearing seat (302) of the bearing assembly (3).

2. The screw air compressor according to claim 1, characterized in that: The bearing assembly (3) includes a bearing housing (302) disposed on the housing (2), and a first end (3021) of the bearing housing (302) extends into the cavity (201); The shaft seal assembly (4) includes: The dynamic sealing unit (40) is located on the shaft (1) and rotates with the shaft (1), including a dynamic sealing ring (401) fixedly installed on the end face of the tooth (101). A static sealing unit (41) is annularly disposed on the shaft (1) and fixedly installed on the end face of the first end (3021), including a static sealing ring (411) disposed opposite to the dynamic sealing ring (401). The static sealing ring (411) is configured to elastically abut against the dynamic sealing ring (401) so that an annular space (5) is formed between the bearing seat (302) and the shaft (1). The bearing housing (302) has multiple outlets (3022) on its peripheral wall that connect the annular space (5) to the outside.

3. The screw air compressor according to claim 2, characterized in that: The dynamic sealing unit (40) further includes a dynamic connector (402), which is fitted onto the shaft (1) and fixedly connected to the tooth (101). The dynamic connector (402) has a mounting groove (4021) for accommodating the dynamic sealing ring (401) on one end face away from the tooth (101). The static sealing unit (41) further includes a static connector (412), which is circumferentially disposed on the shaft (1) and fixed to the first end (3021) of the bearing seat (302). Multiple springs (413) are provided between the static sealing ring (411) and the static connector (412). The multiple springs (413) are arranged in a ring array around the shaft (1), and the two ends of each spring (413) elastically abut against the relatively close two end faces of the static sealing ring (411) and the static connector (412).

4. The screw air compressor according to claim 3, characterized in that: The static sealing ring (411) is made into a stepped shape, and the width of its contact surface with the dynamic sealing ring (401) is 1 / 2 of the diameter of the end face of the dynamic sealing ring (401).

5. The screw air compressor according to claim 3, characterized in that: The static connector (412) is connected to the first end (3021) of the bearing seat (302) via a water seal cover (414). The water seal cover (414) includes a connecting part (4140) fixed to the first end (3021) and a blocking part (4141) extending toward the cavity (201) and surrounding the outer wall of the moving connector (402). A gap is provided between the inner wall surface of the blocking part (4141) and the outer wall surface of the moving connector (402).

6. The screw air compressor according to claim 3, characterized in that: The shaft sealing assembly (4) further includes a centrifugal element (415) sleeved on the shaft (1) and rotating with the shaft, the centrifugal element (415) being located between the bearing (301) and the moving connection (402); The centrifugal component (415) includes a first optical axis portion (4150), a second optical axis portion (4151), and a grid portion (4152) integrally connected between the first optical axis portion (4150) and the second optical axis portion (4151). The end face of the first optical axis portion (4150) is sealed to the end face of the inner ring of the bearing (301) and is clearance-fitted with the bearing seat (302). The second optical axis portion (4151) is sealed to the moving connector (402) and is clearance-fitted with the static sealing unit (41). The grid section (4152) is located in the annular space (5) and is composed of a plurality of centrifugal blades arranged equidistantly along the axial direction of the centrifugal element (415).

7. The screw air compressor according to claim 6, characterized in that: The shaft sealing assembly (4) further includes a sealing sleeve (416), which is fixed by the bearing seat (302) and slidably sealed to the first optical shaft portion (4150); The sealing sleeve (416) stops at one end face of the bearing (301) and extends radially inward from the outer ring of the bearing (301) to abut against the first optical axis portion (4150).

8. The screw air compressor according to claim 7, characterized in that: Multiple trapezoidal grooves (4160) are provided equidistantly along the axial direction on the inner peripheral wall of the sealing sleeve (416) that slides with the first optical axis part (4150).

9. The screw air compressor according to claim 7, characterized in that: The bearing assembly (3) also includes a bearing cover (303), and the two bearing covers (303) are respectively disposed on the two bearing seats (302). One end of the shaft (1) passes through the bearing cap (303) at the corresponding end and connects to the drive source.

10. The screw air compressor according to claim 7, characterized in that: A sliding seal structure (6) is provided between the bearing cap (303) facing the drive source end and the shaft (1). The sliding seal structure (6) includes a spacer (601), a fixing nut (602) and a dust ring (603) arranged sequentially from the inside to the outside along the axial direction on the shaft (1). The spacer (601) is pressed against the bearing (301) by the fixing nut (602) and rotates together with the shaft (1). At the same time, the spacer (601) is slidably sealed to the bearing seat (302) at the corresponding end. The dustproof ring (603) is fixedly connected to the bearing cap (303) at the corresponding end and slides with the shaft (1).

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