Main shaft sealing structure of roots vacuum pump

Abstract

The utility model discloses a main shaft sealing structure of a roots vacuum pump, which comprises a shaft sleeve and a sealing seat, the shaft sleeve is sleeved on a main shaft, the sealing seat is sleeved outside the shaft sleeve, an oil cavity is formed between the sealing seat and the shaft sleeve, a mechanical seal moving ring is arranged in the oil cavity, mechanical seal static rings are arranged at two ends of the oil cavity, and the mechanical seal static rings are used for being connected with the sealing seat. The mechanical seal moving ring is axially connected to the shaft sleeve in a sliding mode, an abutting ring is connected to the mechanical seal moving ring in a sliding mode, the abutting ring abuts against the mechanical seal static ring, and a driving piece for driving the abutting ring to abut against the mechanical seal static ring is arranged on the mechanical seal moving ring. During use, the driving part drives the mechanical seal moving ring to always abut against the mechanical seal static ring, oil in the oil cavity forms a liquid film on the sealing face, and the liquid film plays a role in balancing pressure, lubricating and cooling the end face, so that the mechanical seal does not need to be replaced in actual use, the service life of the pump is prolonged, and the use experience of a user is improved.

Description

Technical Field

[0001] This utility model relates to the field of Roots vacuum pumps, and in particular to a main shaft sealing structure for a Roots vacuum pump. Background Technology

[0002] A Roots vacuum pump is a rotary variable displacement vacuum pump, mainly composed of Roots rotors, pump body, transmission gears, sealing devices, bearings, and drive motor. Its working principle utilizes a pair of synchronously rotating counter-rotating Roots rotors to create periodic volume changes within the pump chamber, thereby transporting gas from the inlet to the outlet, achieving the pumping function.

[0003] The rotor shaft of the Roots vacuum pump extends outward and connects to the drive source motor to transmit power. Currently, the seal of the extended part of the shaft is usually a common oil seal. Under harsh operating conditions, oil leakage often occurs, requiring frequent dispatch of maintenance personnel to replace the oil seal, which is time-consuming and labor-intensive, and also affects the use by customers. Further improvement is needed. Utility Model Content

[0004] To further improve sealing performance and durability, this application provides a spindle seal structure for a Roots vacuum pump.

[0005] This application provides a main shaft sealing structure for a Roots vacuum pump, employing the following technical solution:

[0006] A main shaft sealing structure for a Roots vacuum pump includes a shaft sleeve and a sealing seat. The shaft sleeve is fitted onto the main shaft, and the sealing seat is fitted onto the outside of the shaft sleeve. An oil cavity is formed between the sealing seat and the shaft sleeve. An organic seal moving ring is disposed in the oil cavity, and organic seal stationary rings are disposed at both ends of the oil cavity. The organic seal stationary ring is connected to the sealing seat. The organic seal moving ring is axially slidably connected to the shaft sleeve. An abutment ring is slidably connected to the organic seal moving ring, and the abutment ring abuts against the organic seal stationary ring. A driving component is disposed on the organic seal moving ring to drive the abutment ring to press against the organic seal stationary ring.

[0007] Optionally, the abutment rings are symmetrically arranged at both ends of the mechanical seal moving ring, and the mechanical seal moving ring is provided with a sliding groove for the abutment rings to slide. The driving component includes a spring and is arranged in the sliding groove, and the two ends of the spring are respectively connected to the abutment rings at both ends.

[0008] Optionally, the bushing is provided with a guide groove, and the mechanical seal rotating ring is provided with a guide post that is axially slidably connected to the guide groove.

[0009] Optionally, one end of the sealing seat has a retaining ring that blocks the mechanical seal stationary ring, and the other end of the sealing seat is detachably connected to the mechanical seal pressure cap.

[0010] Optionally, the mechanical seal cover has a mounting groove, and the mechanical seal stationary ring at one end is installed in the mounting groove. A first sealing ring is provided between the mechanical seal stationary ring and the mechanical seal cover to connect the two. The first sealing ring has multiple protruding rings along the axial direction, and the protruding rings abut against the inner wall of the mounting groove.

[0011] Optionally, a sealing ring for sealing is embedded at the surface where the mechanical seal cover abuts against the sealing seat, and the inner diameter of the mechanical seal cover is larger than the outer diameter of the bushing.

[0012] Optionally, the outer wall of the sealing seat is provided with multiple radially penetrating oil inlets, which are evenly distributed around the circumference and are connected to the oil cavity.

[0013] Optionally, it also includes an end cap, the end cap having a central hole adapted to the sealing seat, the end cap being fitted over the sealing seat, and an oil cup being provided on the end cap, the oil cup having an oil outlet communicating with the oil inlet of the sealing seat.

[0014] Optionally, the bottom of the end cap is provided with an oil drain channel, the top of the oil drain channel is connected to the oil cavity, the bottom of the oil drain channel penetrates the bottom of the end cap to form an oil drain port, and a removable plug is provided at the oil drain port.

[0015] Optionally, the guide post is threaded onto the mechanical seal rotating ring, and an oil passage is provided inside the guide post for connecting the oil chamber and the guide groove.

[0016] In summary, this application includes at least one of the following beneficial technical effects:

[0017] 1. A new type of mechanical seal structure is adopted to replace the traditional oil seal structure, which has a good sealing effect. During use, the driving component drives the mechanical seal dynamic ring to always keep in contact with the mechanical seal stationary ring. The oil in the oil chamber forms a liquid film at the sealing surface. The liquid film plays a role in balancing pressure, lubricating and cooling the end face. This eliminates the need to replace the mechanical seal in actual use, improves the service life of the pump and enhances the user experience.

[0018] 2. The driving component includes a spring with both ends of the spring abutting the abutting rings. With the help of a single spring, the abutting rings at both ends can be moved synchronously to achieve elastic compensation, which simplifies the structure. Furthermore, the mechanical seal dynamic ring is axially slidably connected to the bushing, allowing for adaptive adjustment of the axial position according to actual conditions.

[0019] 3. The multiple inlet designs facilitate the entry and exit of oil. Combined with the design of the oil cup and the drain port, the oil in the oil cup will automatically flow down under the action of gravity, realizing the automatic replenishment of oil in the oil chamber. When the oil in the oil chamber needs to be replaced as a whole, the oil in the oil chamber will be discharged from the drain port after the plug is opened. The operation is simple and convenient. Attached Figure Description

[0020] Figure 1 This is an overall structural diagram of Example 1.

[0021] Figure 2 yes Figure 1 Enlarged view of point A in the middle.

[0022] Figure 3 This is a structural diagram of the sealing seat in Example 1.

[0023] Figure 4 This is a structural diagram of Example 2.

[0024] Explanation of reference numerals in the attached figures:

[0025] 1. Bushing; 2. Sealing seat; 3. Main shaft; 4. Oil chamber; 5. Mechanical seal rotating ring; 6. Mechanical seal stationary ring; 7. Abutment ring; 8. Sliding groove; 9. Spring; 10. Guide groove; 11. Guide post; 12. Retaining ring; 13. Mechanical seal gland; 14. Mounting groove; 15. First sealing ring; 16. Raised ring; 17. Oil inlet; 18. End cover; 19. Center hole; 20. Oil cup; 21. Oil outlet; 22. Oil drain channel; 23. Oil drain port; 24. Plug; 25. Oil passage. Detailed Implementation

[0026] The following is in conjunction with the appendix Figure 1-4 This application will be described in further detail.

[0027] Example 1

[0028] A shaft seal structure for a Roots vacuum pump, such as Figure 1 and Figure 2 As shown, the pump includes a bushing 1 and a sealing seat 2. The bushing 1 is fitted onto the main shaft 3 of the Roots vacuum pump and rotates with it. The sealing seat 2 is fitted onto the bushing 1, forming an oil cavity 4 between the sealing seat 2 and the bushing 1. An organic seal moving ring 5 is provided in the oil cavity 4, and organic seal stationary rings 6 are provided at both ends of the oil cavity 4. The mechanical seal stationary rings 6 are connected to the sealing seat 2. The mechanical seal moving ring 5 is axially slidably connected to the bushing 1. Both ends of the mechanical seal moving ring 5 are axially slidably connected to abutment rings 7. The end of the abutment ring 7 abuts against the mechanical seal stationary ring 6. A driving component is provided in the mechanical seal moving ring 5 to drive the abutment ring 7 to always press against the mechanical seal stationary ring 6. A sealing surface is formed at the abutment surface of the abutment ring 7 and the mechanical seal stationary ring 6. In this embodiment, the mechanical seal stationary rings 6 are symmetrically arranged on both sides of the mechanical seal moving ring 5, and two abutment rings 7 are also symmetrically arranged to achieve good sealing at both ends simultaneously.

[0029] like Figure 1 and Figure 2As shown, a groove 8 is provided on the mechanical seal moving ring 5 for the sliding of the abutment ring 7. The driving component includes a spring 9 and is disposed in the groove 8. The two ends of the spring 9 are respectively connected to the abutment rings 7 at both ends. The spring 9 is in a compressed state. With the help of the elastic force of the spring 9, the end of the abutment ring 7 is always pressed against the mechanical seal stationary ring 6 to achieve a good sealing effect and simultaneously achieve the purpose of automatic compensation. The abutment ring 7 is made of graphite ring, which has better wear resistance, thereby improving durability and service life.

[0030] A new type of mechanical seal structure is adopted to replace the traditional oil seal structure, which has a good sealing effect. During use, the driving component drives the mechanical seal dynamic ring 5 to always keep in contact with the mechanical seal stationary ring 6. The oil in the oil chamber 4 forms a liquid film at the sealing surface. The liquid film plays a role in balancing pressure, lubricating and cooling the end face. This eliminates the need to replace the mechanical seal in actual use, improves the service life of the pump and enhances the user experience.

[0031] like Figure 1 and Figure 2 As shown, an axial guide groove 10 is provided on the bushing 1, and a guide post 11 is axially slidably connected in the guide groove 10 on the mechanical seal moving ring 5. The axial movement of the mechanical seal moving ring 5 is adjusted by the cooperation of the guide post 11 and the guide groove 10. Combined with the action of the spring 9, the mechanical seal moving ring 5 can automatically adjust its position according to the actual working conditions to achieve good pressure at both ends, achieve good sealing effect, and the pressure at both ends tends to be balanced, which has better stability. The setting of the guide post 11 enables the mechanical seal moving ring 5 and the bushing 1 to achieve circumferential linkage, that is, when the main shaft 3 and the bushing 1 rotate, they drive the mechanical seal moving ring 5 to rotate synchronously. The mechanical seal stationary ring 6 is connected to the sealing seat 2 and remains stationary without rotation.

[0032] like Figure 1 and Figure 2As shown, one end of the sealing seat 2 has a retaining ring 12 that blocks the stationary mechanical seal ring 6, and the other end of the sealing seat 2 is provided with a mechanical seal cover 13. The mechanical seal cover 13 and the sealing seat 2 are connected by bolts to achieve detachability. The mechanical seal cover 13 and the retaining ring 12 are used to block and limit the axial direction of the mechanical seal rotating ring 5. The mechanical seal cover 13 has an installation groove 14 inside. The mechanical seal stationary ring 6 at one end is installed in the installation groove 14, and the mechanical seal stationary ring 6 at the other end is installed on the side close to the mechanical seal rotating ring 5. A first sealing ring 15 is provided between the mechanical seal stationary ring 6 and the mechanical seal cover 13 to connect the two. The outer wall of the first sealing ring 15 protrudes. There are multiple convex rings 16, which are spaced apart along the axial direction of the first sealing ring 15. The ends of the convex rings 16 are all arc-shaped, which achieves multi-stage sealing at the connection. The arc-shaped end faces of the convex rings 16 make the force at the ends more concentrated and the force at the ends of the convex rings 16 greater, thereby achieving a better sealing effect and preventing oil leakage from between the mechanical seal stationary ring 6 and the mechanical seal gland 13. In addition, a sealing ring is embedded on the surface of the mechanical seal gland 13 that abuts against the sealing seat 2. The sealing ring is used to achieve sealing at the connection between the sealing seat 2 and the mechanical seal gland 13, preventing oil leakage from this point.

[0033] In this embodiment, the inner diameter of the mechanical seal cover 13 is larger than the outer diameter of the bushing 1, so that the mechanical seal cover 13 and the bushing 1 will not come into contact, thereby avoiding interference or wear caused by contact between the two.

[0034] like Figures 1-3 As shown, multiple oil inlets 17 are provided on the outer wall of the sealing seat 2. The oil inlets 17 are evenly distributed around the circumference of the sealing seat 2. The oil inlets 17 penetrate the sealing seat 2 radially and communicate with the oil cavity 4. The oil inlet 17 can replenish the oil in the oil cavity 4.

[0035] like Figures 1-3 As shown, it also includes an end cap 18. The center of the end cap 18 has a central hole 19 that is adapted to the sealing seat 2. The sealing seat 2 is installed in the central hole 19. An oil cup 20 is provided on the end cap 18. An oil outlet 21 is provided at the bottom of the oil cup 20. The oil outlet 21 is connected to the oil inlet 17 on the sealing seat 2. The oil in the oil cup 20 will automatically flow down under the action of gravity, realizing the automatic replenishment of the oil in the oil chamber 4. During operation, the oil in the oil chamber 4 is always sufficient.

[0036] like Figures 1-3 As shown, an oil drain channel 22 communicating with the oil chamber 4 is provided at the bottom of the end cover 18. The bottom end of the oil drain channel 22 passes through the bottom of the end cover 18 to form an oil drain port 23. A plug 24 threadedly connected to the oil drain port 23 is provided at the oil drain port 23. The plug 24 can be rotated to disassemble and assemble. When the oil in the oil chamber 4 needs to be replaced as a whole, the oil in the oil chamber 4 will be discharged from the oil drain port 23 after the plug 24 is opened. The operation is simple and convenient.

[0037] Example 2

[0038] A shaft seal structure for a Roots vacuum pump, such as Figure 4 As shown, the main difference between this embodiment and Embodiment 1 lies in the structure of the guide post 11. In this embodiment, a vertical oil passage 25 is provided in the middle of the guide post 11. The vertical ends of the oil passage 25 penetrate the upper and lower end faces of the guide post 11. The top of the guide post 11 is connected to the oil cavity 4, and the bottom end of the guide post 11 is connected to the guide groove 10. The guide post 11 is threaded onto the mechanical seal rotating ring 5. Thus, in actual use, the vertical position can be adjusted by rotating the guide post 11. A hexagonal operating point is provided on the top of the guide post 11. The position of the guide post 11 corresponds to the oil inlet 17. When the bottom end of the guide post 11 abuts against the bottom wall of the guide groove 10, the bottom end of the oil passage 25 inside the guide post 11 is blocked, and the oil in the oil cavity 4 will not flow into the guide groove 10. Rotating the guide post 11 to move it partially upward can realize the connection between the oil cavity 4 and the guide groove 10. It can be adjusted according to actual needs. The oil entering the guide groove 10 can lubricate the guide groove 10, which makes it easier for the mechanical seal moving ring 5 to move axially and has better smoothness.

[0039] In addition, the guide groove 10 is connected to the slide groove 8, which allows oil to enter the slide groove 8 to lubricate the spring 9, thereby extending the service life of the spring 9 and making the sliding of the abutment ring 7 smoother.

[0040] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A shaft sealing structure for a Roots vacuum pump, characterized in that: The device includes a bushing (1) and a sealing seat (2). The bushing (1) is fitted onto the main shaft (3). The sealing seat (2) is fitted onto the bushing (1). An oil cavity (4) is formed between the sealing seat (2) and the bushing (1). An organic seal moving ring (5) is provided in the oil cavity (4). Organic seal stationary rings (6) are provided at both ends of the oil cavity (4). The organic seal stationary ring (6) is used to connect with the sealing seat (2). The organic seal moving ring (5) is axially slidably connected to the bushing (1). An abutment ring (7) is slidably connected to the organic seal moving ring (5). The abutment ring (7) abuts against the organic seal stationary ring (6). A driving component is provided on the organic seal moving ring (5) to drive the abutment ring (7) to press against the organic seal stationary ring (6).

2. The spindle sealing structure of a Roots vacuum pump according to claim 1, characterized in that: The abutment rings (7) are symmetrically arranged at both ends of the mechanical seal moving ring (5). The mechanical seal moving ring (5) has a sliding groove (8) for the abutment rings (7) to slide. The driving component includes a spring (9) and is arranged in the sliding groove (8). The two ends of the spring (9) are respectively connected to the abutment rings (7) at both ends.

3. The spindle sealing structure of a Roots vacuum pump according to claim 2, characterized in that: The bushing (1) is provided with a guide groove (10), and the mechanical seal ring (5) is provided with a guide post (11) that is axially slidably connected to the guide groove (10).

4. The spindle sealing structure of a Roots vacuum pump according to claim 1, characterized in that: One end of the sealing seat (2) has a retaining ring (12) that blocks the mechanical seal stationary ring (6), and the other end of the sealing seat (2) is detachably connected to the mechanical seal pressure cap (13).

5. The spindle sealing structure of a Roots vacuum pump according to claim 4, characterized in that: The mechanical seal cover (13) has an installation groove (14), and the mechanical seal stationary ring (6) at one end is installed in the installation groove (14). A first sealing ring (15) is provided between the mechanical seal stationary ring (6) and the mechanical seal cover (13) to connect the two. The first sealing ring (15) has multiple protruding rings (16) along the axial direction, and the protruding rings (16) abut against the inner wall of the installation groove (14).

6. The spindle sealing structure of a Roots vacuum pump according to claim 5, characterized in that: A sealing ring for sealing is embedded at the surface where the mechanical seal cover (13) abuts against the sealing seat (2), and the inner diameter of the mechanical seal cover (13) is larger than the outer diameter of the bushing (1).

7. The spindle sealing structure of a Roots vacuum pump according to claim 1, characterized in that: The outer wall of the sealing seat (2) is provided with multiple radially penetrating oil inlets (17), and the multiple oil inlets (17) are evenly distributed around the circumference. The oil inlets (17) are connected to the oil cavity (4).

8. The spindle sealing structure of a Roots vacuum pump according to claim 7, characterized in that: It also includes an end cap (18), which has a central hole (19) that is adapted to the sealing seat (2). The end cap (18) is sleeved on the sealing seat (2). An oil cup (20) is provided on the end cap (18). The oil outlet (21) of the oil cup (20) is connected to the oil inlet (17) of the sealing seat (2).

9. The spindle seal structure of a Roots vacuum pump according to claim 8, characterized in that: The bottom of the end cap (18) is provided with an oil drain channel (22), the top of the oil drain channel (22) is connected to the oil cavity (4), the bottom end of the oil drain channel (22) penetrates the bottom of the end cap (18) to form an oil drain port (23), and a removable plug (24) is provided at the oil drain port (23).

10. The spindle sealing structure of a Roots vacuum pump according to claim 3, characterized in that: The guide post (11) is threaded onto the mechanical seal ring (5). An oil passage (25) is provided inside the guide post (11). The oil passage (25) is used to connect the oil chamber (4) and the guide groove (10).

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