A screw vacuum pump

Abstract

The present invention discloses a screw vacuum pump, belonging to the field of vacuum pumps, including an upper housing. The bottom of the upper housing is fixedly connected with a lower housing. The outer surface of the bottom of the upper housing is welded with a first fixing ring, and the outer surface of the top of the lower housing is welded with a second fixing ring. The first fixing ring and the second fixing ring are detachably connected. The bottom of the first fixing ring extends to form a square block, and a first limiting groove matching the square block is formed inside the second fixing ring. A loosening prevention mechanism is arranged inside the second fixing ring. Only by squeezing the moving rod and then rotating the rotating block can the threaded rod be driven to rotate. After the screwdriver is inserted into the disc, the disc is rotated in the vertical direction, and the hand does not need to contact the outer shell of the device during rotation, making the disassembly more convenient. It effectively prevents the rotating block from rotating due to vibration of the device, which in turn drives the threaded rod to rotate, causing the fixation between the upper housing and the lower housing to become loose and resulting in damage.

Description

Technical Field

[0001] The present invention relates to the field of vacuum pumps, and more particularly, to a screw vacuum pump. Background Art

[0002] A vacuum pump refers to a device or equipment that uses mechanical, physical, chemical, or physical-chemical methods to evacuate a container to obtain a vacuum. Generally speaking, a vacuum pump is a device that improves, generates, and maintains a vacuum in a closed space by various methods. According to the working principle of the vacuum pump, the vacuum pump can basically be divided into two types, namely, a gas capture pump and a gas transfer pump.

[0003] There is a prior patent (publication number: CN105909521A) for a screw vacuum pump. The vacuum pump has a large floor area, and the ultimate pressure that some pump bodies can withstand is small. During the working process, the pump cavity will be corroded, the service life will be affected, it is not convenient to clean, and it may also cause damage to the environment.

[0004] When dirt enters the pump cavity and needs to be cleaned in the above-mentioned patent, only the suction and exhaust ports of the pump need to be opened, and after starting the pump, an appropriate amount of water or cleaning agent can be added from the suction port of the pump to clean the pump. There is no need to disassemble the entire pump. However, during the use process, the vacuum pump will emit high-frequency vibrations, and the vacuum pump housing is fixed by bolts. Long-term vibration is likely to cause the bolts to loosen. Summary of the Invention

[0005] Aiming at the problems existing in the prior art, the purpose of the present invention is to provide a screw vacuum pump. By squeezing the moving rod and then rotating the rotating block, the threaded rod can be driven to rotate. After the screwdriver is inserted into the disc, the disc is rotated in the vertical direction, and the hand does not need to contact the outer shell of the device during rotation, making the disassembly more convenient. It effectively prevents the rotating block from rotating due to vibration of the device, resulting in the rotation of the driving threaded rod, and causing the fixing between the upper shell and the lower shell to become loose and causing damage.

[0006] To solve the above problems, the present invention adopts the following technical solutions.

[0007] A screw vacuum pump includes an upper shell. The bottom of the upper shell is fixedly connected to a lower shell. The outer surface of the bottom of the upper shell is welded with a first fixing ring. The outer surface of the top of the lower shell is welded with a second fixing ring. The first fixing ring and the second fixing ring are detachably connected. The bottom of the first fixing ring extends to form a square block, and a first limiting groove matching the square block is opened inside the second fixing ring;

[0008] A loosening prevention mechanism is provided inside the second fixing ring. The loosening prevention mechanism includes a threaded rod fixed to the second fixing ring by threads. A rotating block is rotatably connected to the front side of the threaded rod. A moving rod is fixed inside the rotating block. A first extension block is formed by extending the outer surface of the moving rod. A second limiting groove is opened inside the threaded rod. A guiding groove is opened on the groove side of the second limiting groove. A disc is fixed to the side of the rotating block away from the threaded rod. The threaded rod horizontally penetrates through the side wall of the second fixing ring and a square block and extends into the inside of the second fixing ring.

[0009] Further, the cross-section of the guiding groove is funnel-shaped. A first spring is provided inside the second limiting groove. One end of the first spring is welded to the threaded rod and the other end is in contact with the moving rod.

[0010] Further, an extrusion rod is formed by extending the surface of the moving rod. A limiting block is slidably connected inside the second fixing ring. An annular groove for the limiting block to extend into is opened inside the rotating block. The cross-sectional shape of the annular groove is circular.

[0011] Further, a second extension block is formed by extending the top of the limiting block. The second extension block is slidably connected inside the second fixing ring. A second spring is welded to one side of the second extension block. The second spring is in a natural stretched state.

[0012] Further, the cross-sectional shape of the limiting block is a right trapezoid. The arc surface of the limiting block is in contact with the extrusion rod. A moving groove for the extrusion rod to move is opened inside the rotating block.

[0013] Further, a piston is fixed to the back side of the threaded rod. A rubber hose is fixed inside the second fixing ring. A connecting pipe is fixed to the front side of the rubber hose. A sealing groove for accommodating the upper half of the rubber hose is opened inside the first fixing ring. The cross-section of the sealing groove is three-quarter elliptical.

[0014] Further, rubber rings are installed inside both the second fixing ring and the first fixing ring. Extrusion grooves are opened inside the rubber rings. Iron rings are fixed to the tops of the rubber rings. Extrusion members are provided on the tops of the iron rings.

[0015] Further, the cross-sectional shape of the extrusion groove is a right trapezoid. The inclined surface of the extrusion groove is mapped downward from the upper vertex of the right endpoint on the right side.

[0016] Further, the extrusion member includes a round rod fixed to the surface of the rubber ring. An arc-shaped plate is fixed to the upper surface of the round rod. The cross-section of the arc-shaped plate is fan-shaped.

[0017] Further, the top of the iron ring is flush with the upper surface of the second fixing ring inside the iron ring. The iron ring is made of plastic, and the rubber ring is made of elastic rubber.

[0018] Compared with the prior art, the advantages of the present invention are as follows:

[0019] (1) In this solution, the threaded rod can be driven to rotate only by squeezing the moving rod and then rotating the rotating block, and the self-rotation of the rotating block cannot drive the threaded rod to rotate. Originally, the screwdriver needs to be inserted into the inside of the disc, so it does not increase the labor force. And after the screwdriver is inserted into the disc, the disc is rotated in the vertical direction, and the hand does not need to contact the outer shell of the device during rotation, making the disassembly more convenient. It effectively prevents the rotating block from rotating due to vibration, which causes the threaded rod to rotate, resulting in the loosening of the fixation between the upper shell and the lower shell and causing damage.

[0020] (2) In this solution, the cross-section of the guiding groove is funnel-shaped. The side surface of the guiding groove guides the first extension block, so that the first extension block reaches the tail of the guiding groove, realizing that the rotation of the rotating block drives the moving rod to rotate, thereby driving the first extension block to rotate. The first extension block drives the threaded rod to rotate, making the rotation more convenient. It avoids the situation that after the moving rod extends into the inside of the threaded rod, the rotation of the rotating block cannot drive the threaded rod to rotate, resulting in the self-rotation of the rotating block, while the threaded rod cannot rotate and cannot fix the first fixing ring and the second fixing ring.

[0021] (3) In this solution, the annular groove is annularly arranged, so that the rotating block can rotate in the annular groove but will not displace, effectively avoiding the movement of the rotating block. It also prevents the threaded rod from moving out of the inside of the second fixing ring due to the movement of the rotating block, resulting in the insecure fixation of the first fixing ring and the second fixing ring. The rotation of the rotating block caused by external force will not cause the threaded rod to rotate, making the fixation more stable and avoiding the loosening or detachment of the threaded rod caused by vibration, resulting in poor stability of the device.

[0022] (4) In this solution, the piston pushes the gas into the inside of the rubber hose. The rubber hose expands inside the sealing groove, and due to the material of the rubber hose, it fills the space inside the sealing groove, increasing the sealing performance at the connection between the first fixing ring and the second fixing ring. And the cross-section of the sealing groove is three-quarter elliptical, making it difficult for the rubber hose inside the sealing groove to leave through the notch of the sealing groove, increasing the stability between the first fixing ring and the second fixing ring and preventing the gas transmitted inside the device from reaching the outside through the device.

[0023] (5) In this solution, the two iron rings squeeze each other, further increasing the airtightness. And through the mutual extrusion of the iron rings, it reduces the corrosion gas from passing through the gap between the rubber rings to one side of the rubber hose, thereby preventing the corrosion gas from contacting the rubber hose and causing damage to the rubber hose. The expansion of the rubber hose inside the sealing groove plays a role of re-sealing, making the sealing effect better.

[0024] (6) In this solution, the round rod drives the arc-shaped plate to move inside the extrusion groove, and the arc-shaped plate extrudes the inner arc surface of the extrusion groove. As the arc-shaped plate extends, the sealing performance becomes better. The arc-shaped plate is fan-shaped, which facilitates the movement of the arc-shaped plate inside the extrusion groove and does not affect the relative movement between the two iron rings. When the transmitted gas is corrosive, the iron rings block it to prevent the gas from corroding the rubber hose. Description of the Drawings

[0025] Figure 1 is a schematic structural diagram of the vacuum pump of the present invention;

[0026] Figure 2 is a schematic structural diagram of the second fixing ring of the present invention;

[0027] Figure 3 is Figure 2 an enlarged view of part A of

[0028] Figure 4 is a schematic structural diagram of the threaded rod of the present invention;

[0029] Figure 5 is a schematic structural diagram of the moving rod of the present invention;

[0030] Figure 6 is a schematic structural diagram of the rubber ring of the present invention;

[0031] Figure 7 is a half-sectional view of the second fixing ring of the present invention;

[0032] Figure 8 is a schematic structural diagram of the extrusion member of the present invention;

[0033] Figure 9 is a schematic structural diagram of the rotating block of the present invention;

[0034] Figure 10 is a cross-sectional view of the rubber ring of the present invention.

[0035] Description of the Reference Numerals in the Drawings:

[0036] 1. Upper housing; 2. First fixing ring; 21. Square block; 22. Sealing groove; 3. Second fixing ring; 31. First limiting groove; 4. Lower housing; 5. Anti-loosening mechanism; 51. Piston; 52. Threaded rod; 521. Guide groove; 522. Second limiting groove; 53. Disc; 54. Moving rod; 541. Extrusion rod; 542. First extension block; 55. Rotating block; 551. Moving groove; 552. Annular groove; 56. First spring; 6. Rubber hose; 61. Connecting pipe; 7. Rubber ring; 71. Extrusion groove; 72. Extrusion member; 721. Arc-shaped plate; 722. Round rod; 73. Iron ring; 8. Limiting block; 81. Second extension block; 82. Second spring. Detailed implementation mode

[0037] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention; obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0038] Embodiment 1:

[0039] Please refer to Figures 1 to 3 , a screw vacuum pump, including an upper housing 1, the bottom of the upper housing 1 is fixedly connected with a lower housing 4, the outer surface of the bottom of the upper housing 1 is welded with a first fixing ring 2, the outer surface of the top of the lower housing 4 is welded with a second fixing ring 3, the first fixing ring 2 and the second fixing ring 3 are detachably connected, the bottom of the first fixing ring 2 extends to form a square block 21, and the inside of the second fixing ring 3 is provided with a first limiting groove 31 matching the square block 21;

[0040] A loosening prevention mechanism 5 is arranged inside the second fixing ring 3. The loosening prevention mechanism 5 includes a threaded rod 52 fixedly connected to the second fixing ring 3 through threads. A rotating block 55 is rotatably connected to the front side of the threaded rod 52. A moving rod 54 is fixed inside the rotating block 55. The outer surface of the moving rod 54 extends to form a first extension block 542. A second limiting groove 522 is opened inside the threaded rod 52. A guiding groove 521 is opened on the groove side of the second limiting groove 522. A disc 53 is fixed on the side of the rotating block 55 away from the threaded rod 52. The threaded rod 52 horizontally penetrates through the side wall of the second fixing ring 3 and the square block 21 and extends into the inside of the second fixing ring 3.

[0041] By fitting the first fixing ring 2 with the second fixing ring 3 together, making the square block 21 pass through the first limiting groove 31, and passing the threaded rod 52 through the first limiting groove 31 and the square block 21 in sequence and then reaching the inside of the second fixing ring 3, the fixation of the square block 21 and the first limiting groove 31 is achieved. During the movement process, it is necessary to squeeze the moving rod 54 so that the first extension block 542 on the surface of the moving rod 54 reaches the inside of the guiding groove 521, making the disc 53 rotate and driving the rotating block 55 to rotate. The rotating block 55 rotates and drives the threaded rod 52 to rotate, making the rotating block 55 drive the threaded rod 52 to extend into the inside of the second fixing ring 3. Then, pull the moving rod 54 to make the moving rod 54 disengage from the inside of the threaded rod 52. After the moving rod 54 disengages from the inside of the threaded rod 52, the rotation of the rotating block 55 will not drive the threaded rod 52 to rotate. When the threaded rod 52 is vibrated, since the rotating block 55 cannot disengage from the inside of the second fixing ring 3 by rotation, it is difficult for the threaded rod 52 to be vibrated and rotate inside the second fixing ring 3, effectively preventing the threaded rod 52 from disengaging from the inside of the second fixing ring 3 due to the vibration of the device, making the fixation more firm. And when disassembling, when the screwdriver is inserted into the inside of the disc 53, it will squeeze the moving rod 54, making the moving rod 54 extend into the inside of the threaded rod 52. Only by rotating the rotating block 55 can the threaded rod 52 be driven to rotate. And originally, the screwdriver needs to be inserted into the inside of the disc 53, so the labor force will not be increased. And after the screwdriver is inserted into the disc 53, the disc 53 is rotated in the vertical direction, and it will not be necessary for the hand to contact the outer shell of the device when rotating, making the disassembly more convenient, effectively preventing the device from being damaged due to the rotation of the rotating block 55 caused by vibration, resulting in the rotation of the driving threaded rod 52 and the loosening of the fixation between the upper shell 1 and the lower shell 4.

[0042] As Figure 3 shown, the cross-section of the guiding groove 521 is funnel-shaped, and a first spring 56 is arranged inside the second limiting groove 522. One end of the first spring 56 is welded to the threaded rod 52 and the other end is in contact with the moving rod 54.

[0043] By adopting the above technical solution, the moving rod 54 drives the first extension block 542 to move, so that the first extension block 542 reaches the inside of the guiding groove 521. The cross-section of the guiding groove 521 is funnel-shaped, so that the side wall of the guiding groove 521 squeezes the first extension block 542, causing the first extension block 542 to drive the moving rod 54 to rotate inside the second limiting groove 522. The first extension block 542 reaches the tail of the guiding groove 521 through the guiding on the side of the guiding groove 521, realizing the rotation of the rotating block 55 driving the moving rod 54 to rotate, thereby driving the first extension block 542 to rotate. The first extension block 542 drives the threaded rod 52 to rotate, making the rotation more convenient. After the moving rod 54 extends into the threaded rod 52, if the rotating block 55 rotates and cannot drive the threaded rod 52 to rotate, it will cause the rotating block 55 to rotate by itself, and the threaded rod 52 cannot rotate, so the first fixing ring 2 and the second fixing ring 3 cannot be fixed.

[0044] As Figures 2 - 3 and Figure 9 As shown, an extrusion rod 541 is formed by extending the surface of the moving rod 54. A limiting block 8 is slidably connected inside the second fixing ring 3. An annular groove 552 for the limiting block 8 to extend into is formed inside the rotating block 55. The cross-sectional shape of the annular groove 552 is circular. A second extension block 81 is formed by extending the top of the limiting block 8. The second extension block 81 is slidably connected inside the second fixing ring 3. A second spring 82 is welded to one side of the second extension block 81. The second spring 82 is in a natural stretched state. The cross-sectional shape of the limiting block 8 is a right trapezoid. The arc surface of the limiting block 8 is in contact with the extrusion rod 541. A moving groove 551 for the extrusion rod 541 to move is formed inside the rotating block 55.

[0045] By adopting the above technical solution, when the rotating block 55 rotates and moves, the moving groove 551 moves along with the rotating block 55. After the moving groove 551 reaches one side of the limiting block 8, the limiting block 8 moves inside the second fixing ring 3 due to the second spring 82 squeezing the second extension block 81. After the limiting block 8 moves, it reaches inside the annular groove 552. By engaging the limiting block 8 into the annular groove 552, the displacement of the rotating block 55 inside the second fixing ring 3 is effectively restricted. Since the annular groove 552 is annular, the rotating block 55 can rotate but will not displace, effectively preventing the moving of the rotating block 55 and further preventing the threaded rod 52 from moving out of the second fixing ring 3 due to the movement of the rotating block 55, which may cause the first fixing ring 2 and the second fixing ring 3 to be insecurely fixed. When disassembling, while pressing the moving rod 54, the moving rod 54 will drive the extrusion rod 541 to move inside the moving groove 551, causing the extrusion rod 541 to squeeze the arc surface of the limiting block 8, making the limiting block 8 return to the inside of the second fixing ring 3. Rotating the rotating block 55 can drive the threaded rod 52 to rotate, causing the threaded rod 52 to disengage from the inside of the second fixing ring 3. Even if the rotating block 55 is rotated by an external force, the threaded rod 52 will not rotate, making the fixation more stable and avoiding the loosening or disengagement of the threaded rod 52 caused by vibration, which may lead to poor stability of the device.

[0046] As Figure 6 shown, a piston 51 is fixed to the back side of the threaded rod 52. A rubber hose 6 is fixed inside the second fixing ring 3. A connecting pipe 61 is fixed to the front side of the rubber hose 6. A sealing groove 22 for accommodating the upper half of the rubber hose 6 is formed inside the first fixing ring 2. The cross-section of the sealing groove 22 is three-quarter elliptical.

[0047] By adopting the above technical solution, the movement of the threaded rod 52 drives the piston 51 to move inside the second fixing ring 3, causing the piston 51 to push the gas through the connecting pipe 61 into the inside of the rubber hose 6, filling the inside of the rubber hose 6 with gas and causing it to expand. The top of the rubber hose 6 extends into the inside of the sealing groove 22, and the rubber hose 6 inside the sealing groove 22 also expands together. As the rubber hose 6 expands inside the sealing groove 22 and due to the material of the rubber hose 6, the space inside the sealing groove 22 is filled, increasing the sealing performance at the connection between the first fixing ring 2 and the second fixing ring 3. Moreover, since the cross-section of the sealing groove 22 is three-quarter elliptical, it is difficult for the rubber hose 6 inside the sealing groove 22 to leave through the notch of the sealing groove 22, increasing the stability between the first fixing ring 2 and the second fixing ring 3 and preventing the gas transmitted inside the device from reaching the outside through the device.

[0048] As Figure 8As shown, rubber rings 7 are installed inside both the second fixing ring 3 and the first fixing ring 2. Extrusion grooves 71 are formed inside the rubber rings 7. Iron rings 73 are fixed to the tops of the rubber rings 7, and extrusion members 72 are arranged on the tops of the iron rings 73.

[0049] By adopting the above technical solution, after inserting the square block 21 into the first limiting groove 31, the extrusion member 72 inside the first fixing ring 2 extends into the extrusion groove 71 inside the second fixing ring 3. Conversely, the extrusion member 72 inside the second fixing ring 3 extends into the extrusion groove 71 inside the first fixing ring 2. By rotating the first limiting groove 31, the square block 21 is aligned with the circular hole inside the first limiting groove 31. At the same time of alignment, the extrusion member 72 squeezes the top of the extrusion groove 71, driving the top of the rubber ring 7 on the surface of the second fixing ring 3 to move upward, causing the rubber ring 7 to drive the iron ring 73 to move upward, while the rubber ring 7 on the surface of the first fixing ring 2 moves downward, causing the two iron rings 73 to squeeze each other, further increasing the airtightness. And by the mutual extrusion of the iron rings 73, it reduces the corrosive gas from passing through the gap between the rubber rings 7 to reach one side of the rubber hose 6, thereby preventing the corrosive gas from contacting the rubber hose 6 and causing damage to the rubber hose 6. The rubber hose 6 expands inside the sealing groove 22, playing a role of re-sealing and making the sealing effect better.

[0050] As Figure 7 and Figure 8 and Figure 10 As shown, the cross-section of the extrusion groove 71 is a right trapezoid. The inclined surface of the extrusion groove 71 is mapped downward along the upper vertex of the right endpoint. The extrusion member 72 includes a round rod 722 fixed to the surface of the rubber ring 7. An arc-shaped plate 721 is fixed to the upper surface of the round rod 722. The cross-section of the arc-shaped plate 721 is a sector. The top of the iron ring 73 is flush with the upper surface of the second fixing ring 3 inside the iron ring 73. The material of the iron ring 73 is plastic, and the material of the rubber ring 7 is elastic rubber.

[0051] By adopting the above technical solution, the round rod 722 drives the arc-shaped plate 721 to move inside the extrusion groove 71, and the arc-shaped plate 721 squeezes the inclined surface inside the extrusion groove 71. As the arc-shaped plate 721 extends, the sealing performance becomes better. And the arc-shaped plate 721 is a sector, which is convenient for the arc-shaped plate 721 to move inside the extrusion groove 71 and does not affect the relative movement between the two iron rings 73. When the transmitted gas is corrosive, the iron ring 73 blocks it to prevent the gas from corroding the rubber hose 6.

[0052] Usage method: After inserting the square block 21 into the first limiting groove 31, rotate the first limiting groove 31 to align the square block 21 with the hole in the first limiting groove 31. By squeezing the moving rod 54, the moving rod 54 extends into the threaded rod 52. By rotating the rotating block 55, the rotating block 55 drives the threaded rod 52 to rotate and gradually extend into the interior of the second fixing ring 3. After the moving groove 551 reaches one side of the limiting block 8, release the moving rod 54, and the extrusion rod 541 leaves the moving groove 551. The limiting block 8 extends into the annular groove 552 to limit the displacement of the rotating block 55. The moving rod 54 returns to its original position under the elasticity of the first spring 56, making the rotating block 55 can only rotate but not displace. To disassemble, just press the moving rod 54 again to make the extrusion rod 541 squeeze the limiting block 8, so that the limiting block 8 returns to its original position. The first extension block 542 reaches the guiding groove 521, and the rotating disc 53 drives the rotating block 55 and the threaded rod 52 to rotate to take out the threaded rod 52. While the threaded rod 52 moves, it drives the piston 51 to move, injecting gas into the rubber hose 6 to make the rubber hose 6 expand in the sealing groove 22. When the second fixing ring 3 rotates, it drives the two iron rings 73 to move relative to each other.

[0053] The above is only a preferred specific embodiment of the present invention; however, the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution and its improvement concept of the present invention, makes equivalent substitutions or changes, and should be covered by the protection scope of the present invention.

Claims

1. A screw vacuum pump, comprising an upper housing (1), the bottom of the upper housing (1) being fixedly connected to a lower housing (4), characterized in that: The bottom outer surface of the upper housing (1) is welded with a first fixing ring (2), the top outer surface of the lower housing (4) is welded with a second fixing ring (3), the first fixing ring (2) is detachably connected to the second fixing ring (3), a square block (21) is formed by extending the bottom of the first fixing ring (2), and a first limiting groove (31) matching the square block (21) is formed inside the second fixing ring (3); A loosening prevention mechanism (5) is arranged inside the second fixing ring (3). The loosening prevention mechanism (5) includes a threaded rod (52) fixed to the second fixing ring (3) by threads. A rotating block (55) is rotatably connected to the front side of the threaded rod (52). A moving rod (54) is fixed inside the rotating block (55). A first extension block (542) is formed by extending the outer surface of the moving rod (54). A second limiting groove (522) is formed inside the threaded rod (52). A guiding groove (521) is formed on the groove side of the second limiting groove (522). A disc (53) is fixed to the side of the rotating block (55) away from the threaded rod (52). The threaded rod (52) horizontally penetrates through the side wall of the second fixing ring (3) and the square block (21) and extends into the inside of the second fixing ring (3); A piston (51) is fixed to the back side of the threaded rod (52). A rubber hose (6) is fixed inside the second fixing ring (3). A connecting pipe (61) is fixed to the front side of the rubber hose (6). A sealing groove (22) for accommodating the upper half of the rubber hose (6) is formed inside the first fixing ring (2). The cross section of the sealing groove (22) is three-quarter elliptical. The piston (51) pushes gas to reach the inside of the rubber hose (6) through the connecting pipe (61); Rubber rings (7) are installed inside both the second fixing ring (3) and the first fixing ring (2). Pressing grooves (71) are formed inside the rubber rings (7). Iron rings (73) are fixed to the tops of the rubber rings (7). Pressing members (72) are arranged on the tops of the iron rings (73).

2. The screw vacuum pump according to claim 1, wherein: The cross section of the guiding groove (521) is funnel-shaped. A first spring (56) is arranged inside the second limiting groove (522). One end of the first spring (56) is welded to the threaded rod (52) and the other end is in contact with the moving rod (54).

3. A screw vacuum pump according to claim 1, characterized in that: An extrusion rod (541) is formed by extending the surface of the moving rod (54). A limiting block (8) is slidably connected to the inside of the second fixing ring (3). An annular groove (552) for accommodating the limiting block (8) to extend into is formed inside the rotating block (55). The cross section shape of the annular groove (552) is circular ring-shaped.

4. A screw vacuum pump according to claim 3, characterized in that: A second extension block (81) is formed by extending the top of the limiting block (8). The second extension block (81) is slidably connected to the inside of the second fixing ring (3). A second spring (82) is welded to one side of the second extension block (81). The second spring (82) is in a natural stretched state.

5. The screw vacuum pump according to claim 3, wherein: The cross-sectional shape of the limiting block (8) is a right trapezoid. The arc surface of the limiting block (8) is in contact with the extrusion rod (541). A moving groove (551) for the movement of the extrusion rod (541) is provided inside the rotating block (55).

6. The screw vacuum pump according to claim 1, characterized in that: The cross-sectional shape of the extrusion groove (71) is a right trapezoid, and the inclined surface of the extrusion groove (71) is mapped downward along the upper vertex of the right endpoint.

7. A screw vacuum pump according to claim 1, wherein: The extrusion member (72) includes a round rod (722) fixed to the surface of the rubber ring (7). An arc-shaped plate (721) is fixed to the upper surface of the round rod (722), and the cross-section of the arc-shaped plate (721) is a sector.

8. A screw vacuum pump according to claim 1, characterized in that: The top of the iron ring (73) is flush with the upper surface of the second fixing ring (3) inside the iron ring (73). The material of the iron ring (73) is plastic, and the material of the rubber ring (7) is elastic rubber.

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