Roots vacuum pump with easy start

Abstract

The application relates to a Roots vacuum pump convenient to start, which comprises a pump body with a pump cavity, two rotors and a driving motor, and further comprises a driving assembly, one end of the pump cavity is arranged in a taper shape from one end to the other end in the length direction, the two rotors are rotationally connected in the pump cavity, one end of the two rotors is arranged in a taper shape from one end to the other end in the length direction, rotating shafts are arranged on the two rotors, the rotating shafts are slidably connected on the pump body, a sliding sleeve is arranged on any rotating shaft, the driving motor is arranged on the pump body, the sliding sleeve is slidably connected on the output shaft of the driving motor, the driving assembly is used for driving the sliding of the rotating shafts, and the gap between the rotors and the pump cavity changes after the two rotating shafts are driven to move. In the starting stage, the larger gap makes the resistance smaller when the rotors rotate in the pump cavity, the torque required for driving the rotors to rotate is smaller, and the power consumption in the starting stage is reduced; along with the operation of the pump, the gap is gradually reduced, the gas entering the pump cavity is more effectively compressed, and the air-pumping efficiency is improved.

Description

Technical Field

[0001] This invention relates to the field of Roots vacuum pump technology, and in particular to a Roots vacuum pump that is easy to start. Background Technology

[0002] A Roots vacuum pump is a common type of vacuum pump that uses the pushing action of a pair of lobe-shaped rotors rotating synchronously and in opposite directions within the pump chamber to move gas and achieve pumping. The gas to be pumped is drawn in from the inlet into the space between the rotor and the pump casing, and then discharged through the outlet. When the top of the rotor passes the edge of the outlet and the space connects with the exhaust side, some gas backflows, causing a sudden increase in pressure. The rotor then continues to rotate, expelling the gas from the pump.

[0003] The clearance between the pump chamber wall and the rotor in a Roots vacuum pump is fixed and typically small. During startup, the motor speed is not yet stable, resulting in high rotor rotational resistance and a large torque required for the motor to drive the rotor. Furthermore, the fixed, small clearance leads to high resistance between the rotor and the pump chamber wall, resulting in a high starting load and low starting efficiency for the Roots vacuum pump. Summary of the Invention

[0004] To improve the starting efficiency of Roots vacuum pumps, this application provides a Roots vacuum pump that is easy to start.

[0005] The Roots vacuum pump that is easy to start provided in this application adopts the following technical solution:

[0006] A Roots vacuum pump that is easy to start includes a pump body with a pump chamber, two rotors, and a drive motor, and also includes a drive assembly. The pump chamber is tapered from one end to the other along its length. The two rotors are rotatably connected within the pump chamber, and each rotor has a rotating shaft that is slidably connected to the pump body. Each rotating shaft has a sliding sleeve. The drive motor is mounted on the pump body, and the sliding sleeve is slidably connected to the output shaft of the drive motor. The drive assembly is used to drive the sliding of the rotating shafts. When the drive assembly drives the two rotating shafts to move, the gap between the rotors and the pump chamber changes.

[0007] By adopting the above technical solution, during the start-up phase, the larger gap reduces the resistance experienced by the rotor when rotating in the pump chamber, resulting in a smaller torque required for the motor to drive the rotor, thus reducing power consumption during startup. During the initial pumping phase, the larger gap facilitates the rapid discharge of a large amount of gas. As the pumping process progresses, gradually reducing the gap can increase the gas compression ratio and more effectively extract gas, thereby improving the overall pumping performance.

[0008] Preferably, two retaining plates are slidably connected inside the pump chamber. Two grooves are respectively opened on the two retaining plates. Thin-walled bearings are respectively provided at both ends of the two rotating shafts along the axial direction. The inner rings of the two thin-walled bearings are respectively fixed coaxially and fixedly connected to the rotating shafts. The outer rings of the two thin-walled bearings are respectively slidably connected in the grooves along their radial direction.

[0009] By adopting the above technical solution, the setting of the retaining plate maintains an axial clearance between the rotor and the retaining plate, reducing the possibility of collision and friction between the rotor end and the cavity wall caused by excessive rotor movement. The radial sliding design allows the rotating shaft to adaptively offset small deviations, improving operational stability and avoiding jamming.

[0010] Preferably, the drive assembly includes a sliding plate, a threaded rod, and an adjusting component. The sliding plate is slidably connected to the pump body, and two sliding blocks are slidably connected to the sliding plate. One end of each of the two rotating shafts is rotatably connected to the corresponding sliding block. The threaded rod is rotatably connected to the pump body and passes through and is threadedly connected to the sliding plate. The adjusting component is used to drive the rotation of the threaded rod.

[0011] By adopting the above technical solution, the threaded rod and the sliding plate are threadedly connected. When the threaded rod rotates, the sliding plate will move along the axis of the threaded rod. By adjusting the rotation angle and number of turns of the threaded rod, the moving distance of the sliding plate can be precisely controlled, thereby precisely adjusting the gap between the rotor and the pump chamber.

[0012] Preferably, the adjusting component includes a nut seat, a one-way bearing, a hydraulic cylinder, and a second spring. The nut seat is rotatably connected to a sliding plate. The outer ring of the one-way bearing is located on the sliding plate, and the inner ring of the one-way bearing is located on the nut seat. A threaded rod passes through and is threadedly connected to the nut seat. The threaded rod has a smooth section and a second gear is provided on the threaded rod. The drive motor has a first gear. The first gear and the second gear mesh together to form a gear set. The hydraulic cylinder is fixedly connected to the pump body. One end of the piston rod of the hydraulic cylinder is fixedly connected to the sliding plate. The second spring is sleeved on the threaded rod. The two ends of the second spring are respectively fixedly connected to the pump body and the sliding seat. When the threaded rod rotates, the nut seat cannot rotate and moves towards the smooth section. The gap between the rotor and the inner wall of the pump cavity gradually decreases, the second spring deforms, and the piston rod of the hydraulic cylinder retracts.

[0013] By adopting the above technical solution, the drive motor operates, which in turn drives the first gear and the second gear to rotate. The gear set is used to reduce the transmission ratio between the first gear and the second gear, so that the threaded rod rotates together. When the threaded rod rotates, the nut seat moves along the axial direction of the threaded rod towards the smooth section, so that the gap between the rotor and the inner wall of the pump cavity gradually decreases. When the nut seat moves to the smooth section, it stops moving. During the movement of the nut seat, the second spring is deformed by force, and the piston rod of the hydraulic cylinder gradually retracts. When the threaded rod stops rotating, the second spring returns to its original position, causing the nut seat to move. The movement of the nut seat applies a small external force to the piston rod of the hydraulic cylinder, which is transmitted to the piston of the hydraulic cylinder through the hydraulic oil. Since the piston surface will generate a large thrust on the piston, it pushes the piston rod out, and the sliding plate is pushed back to its original position.

[0014] Preferably, the threaded rod has a rotating section, a rotating block is threadedly connected to the rotating section, a limiting block is provided on the rotating block, the limiting block is arranged in a tapered shape, a limiting groove is provided on the nut seat, and the two ends of the second spring abut against the rotating block and the pump body respectively. When the nut seat moves towards the smooth section, the nut seat pushes the rotating block to move, and the limiting block slips between itself and the limiting groove. When the nut seat resets, the limiting block and the limiting groove cooperate.

[0015] By adopting the above technical solution, when the nut seat moves towards the smooth section, the nut seat moves to abut against the rotating block and pushes the rotating block to move and rotate on the rotating section, causing the second spring to deform under force. When the threaded rod stops rotating, the second spring recovers and pushes the rotating block to move and rotate towards the threaded seat. When the limiting block and the limiting groove cooperate, the rotating block drives the nut seat to rotate together, so that the nut seat and the threaded rod are threadedly connected, reducing the possibility of jamming during the nut seat reset process.

[0016] Preferably, the pump body is provided with a slide rod, the slide rod passes through a sliding plate, the slide rod is provided with a plurality of limiting protrusions, and the surface of the plurality of limiting protrusions is provided with elastic anti-slip sheets. When the sliding plate moves to the smooth section, the elastic anti-slip sheets abut against the sliding plate.

[0017] By adopting the above technical solution, when the sliding plate moves to the limit protrusion position and abuts against the elastic anti-slip plate, it can effectively prevent the sliding plate from accidentally sliding due to external vibrations, minor vibrations generated by equipment operation, and other factors. This increases the stability of the position after the gap between the rotor and the pump chamber is adjusted.

[0018] Preferably, the two ends of the two rotating shafts are coaxial and fixedly connected to sliding seats, and multiple sliding seats are slidably connected to the pump body along the axial direction of the corresponding transmission shaft, and the circumferential sides of the two sliding seats located at the same end abut against each other.

[0019] By adopting the above technical solution, the circumferential sides of the two sliding seats located at the same end abut against each other. When the drive assembly moves the rotating shaft, the two sliding seats move synchronously, thereby causing the gap between the two rotors and the pump chamber to change simultaneously and uniformly. This reduces the possibility of uneven gas flow within the pump chamber due to uneven gap adjustment, which could affect the pumping effect.

[0020] Preferably, the pump body has two spur gears rotatably connected to each other, the two spur gears are meshed with each other, and each of the two spur gears is provided with a universal coupling, the other end of the two universal couplings is fixedly connected to the rotating shaft.

[0021] By adopting the above technical solution, the two meshing spur gears can ensure the synchronicity and stability of rotation; the universal coupling can adapt to changes in the rotor's position, ensuring the normal rotation of the rotor and reducing the possibility of transmission interruption or instability caused by changes in the position of the rotating shaft.

[0022] The main technical effects of this invention are reflected in the following aspects:

[0023] This invention arranges the two pump chambers and the rotor in a tapered manner, with the rotor slidably connected within the pump chamber. When the vacuum pump heats up, the drive assembly moves the rotating shaft, increasing the gap between the rotor and the inner wall of the pump chamber, thereby reducing the possibility of friction between the rotor and the inner wall of the pump chamber. When the vacuum pump is not heating up, the reduced gap decreases the possibility of gas backflow and leakage. The gap can be adjusted in real time during pump operation, improving gas compression efficiency and making the vacuum pump perform better.

[0024] 2. By setting two retaining plates, the present invention maintains an axial clearance between the rotor and the retaining plates, reducing the possibility of collision and friction between the rotor end and the cavity wall caused by excessive rotor movement. The radial sliding design allows the rotating shaft to adapt to small offsets, improving operational stability and avoiding jamming.

[0025] 3. By setting a rotating section, when the nut seat moves towards the smooth section, the nut seat moves to abut against the rotating block and pushes the rotating block to move and rotate on the rotating section, causing the second spring to deform under force. When the threaded rod stops rotating, the second spring recovers and pushes the rotating block to move and rotate towards the threaded seat. When the limiting block and the limiting groove cooperate, the rotating block drives the nut seat to rotate together, so that the nut seat and the threaded rod are threadedly connected, reducing the possibility of jamming during the nut seat reset process. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the overall structure of an embodiment of this application.

[0027] Figure 2This is a schematic diagram of the starter motor structure in an embodiment of this application.

[0028] Figure 3 This is a schematic diagram of the pump chamber structure according to an embodiment of this application.

[0029] Figure 4 It is along Figure 3 Enlarged view of point A in the middle.

[0030] Figure 5 This is a schematic diagram of the threaded rod structure according to an embodiment of this application.

[0031] Figure 6 It is along Figure 5 Enlarged view of point B in the middle.

[0032] Figure 7 This is a schematic diagram of the rotor structure according to an embodiment of this application.

[0033] Figure 8 This is a schematic diagram of the retaining plate structure in an embodiment of this application.

[0034] Figure 9 This is a schematic diagram of the sliding plate structure in an embodiment of this application.

[0035] Explanation of reference numerals in the attached drawings: 1. Pump body; 2. Pump chamber; 3. Rotor; 4. Drive motor; 5. Drive assembly; 51. Sliding plate; 52. Threaded rod; 521. Smooth section; 522. Rotating section; 523. Rotating block; 524. Limiting block; 525. Limiting groove; 53. Sliding block; 54. Adjusting component; 541. Nut seat; 542. One-way bearing; 543. Hydraulic cylinder; 544. Second spring; 545. First gear; 546. Second gear; 547. Gear set; 6. Rotating shaft; 7. Sliding sleeve; 8. Holding plate; 9. Groove; 10. Thin-walled bearing; 18. Sliding rod; 19. Limiting protrusion; 21. Spur gear; 22. Universal coupling. Detailed Implementation

[0036] The following is in conjunction with the appendix Figures 1-9 This application will be described in further detail to make the technical solution of this application easier to understand and master.

[0037] This application discloses a Roots vacuum pump that is easy to start.

[0038] Reference Figure 1 , Figure 3 and Figure 4This embodiment of a Roots vacuum pump that is easy to start includes a pump body 1 with a pump chamber 2, two rotors 3 and a drive motor 4, and a drive assembly 5. The pump chamber 2 is tapered from one end to the other along its length. The two rotors 3 are rotatably connected inside the pump chamber 2. The two rotors 3 are tapered from one end to the other along their length. Rotating shafts 6 are coaxially and fixedly connected to the two rotors 3, and the rotating shafts 6 are slidably connected to the pump body 1. A sliding sleeve 7 is coaxially and fixedly connected to each rotating shaft 6. The drive motor 4 is fixedly connected to the pump body 1. The larger end of the tapered section of the pump chamber 2 is located on one side of the drive motor 4. The two rotors 3 are arranged in the same way as the pump chamber 2. The sliding sleeve 7 is coaxially and slidably connected to the output shaft of the drive motor 4. The drive assembly 5 is used to drive the sliding of the rotating shafts 6. When the drive assembly 5 drives the two rotating shafts 6 to move, the gap between the rotors 3 and the pump chamber 2 changes.

[0039] Reference Figure 3 , Figure 4 and Figure 8 Two retaining plates 8 are slidably connected inside the pump chamber 2. Each retaining plate 8 has two grooves 9. Thin-walled bearings 10 are installed at both ends of the two rotating shafts 6 along their axial directions. The inner rings of the two thin-walled bearings 10 are fixed coaxially and fixedly connected to the rotating shafts 6, while the outer rings of the two thin-walled bearings 10 are slidably connected radially within the grooves 9. The retaining plates 8 maintain an axial clearance between the rotor 3 and the retaining plates 8, reducing the possibility of collision and friction between the rotor 3 end and the chamber wall due to excessive rotor movement. The radial sliding design allows the rotating shafts 6 to adaptively make small offsets, improving operational stability and preventing jamming.

[0040] Reference Figure 3 and Figure 5 The drive assembly 5 includes a sliding plate 51, a threaded rod 52, and an adjusting component 54. The sliding plate 51 is slidably connected to the pump body 1. Two sliding blocks 53 are slidably connected to the sliding plate 51 along the radial direction of the two rotating shafts 6. One end of the two rotating shafts 6 is rotatably connected to the corresponding sliding block 53. The threaded rod 52 is rotatably connected to the pump body 1. The threaded rod 52 passes through and is threadedly connected to the sliding plate 51. The adjusting component 54 is used to drive the rotation of the threaded rod 52.

[0041] Reference Figure 3 and Figure 7The adjusting component 54 includes a nut seat 541, a one-way bearing 542, a hydraulic cylinder 543, and a second spring 544. The nut seat 541 is rotatably connected to the sliding plate 51 along the moving direction of the sliding plate 51. The outer ring of the one-way bearing 542 is fixedly connected to the sliding plate 51, and the inner ring of the one-way bearing 542 is fixedly connected to the sliding seat. A threaded rod 52 passes through and is threadedly connected to the nut seat 541. The threaded rod 52 has a smooth section 521 on its upper part, and a second gear 546 is coaxially and fixedly connected to the threaded rod 52. A first gear 545 is coaxially and fixedly connected to the output shaft of the drive motor 4. The first gear 545 and the second gear 546 mesh together to form a gear set 547. The gear set 547 is used to reduce the transmission speed between the first gear 545 and the second gear 546. Hydraulic cylinder 543 is fixedly connected to pump body 1, with the cylinder body portion of hydraulic cylinder 543 embedded within pump body 1. One end of the piston rod of hydraulic cylinder 543 is fixedly connected to a sliding plate. A second spring 544 is sleeved on threaded rod 52, with both ends of the second spring 544 fixedly connected to pump body 1 and sliding seat, respectively. When threaded rod 52 rotates, nut seat 541 cannot rotate and moves towards the smooth section 521, gradually reducing the gap between rotor 3 and the inner wall of pump chamber 2. The second spring 544 deforms, and the piston rod of hydraulic cylinder 543 retracts. When threaded rod 52 stops rotating, the second spring 544 returns to its original position, causing nut seat 541 to rotate and move to be threadedly connected to threaded rod 52. The piston rod of hydraulic cylinder 543 extends and resets, and the gap between rotor 3 and pump chamber 2 gradually increases.

[0042] Reference Figure 5 and Figure 6 The threaded rod 52 is provided with a rotating section 522, which is a multi-threaded section. A rotating block 523 is threadedly connected to the rotating section 522. A limit block 524 is fixedly connected to the rotating block 523. The limit block 524 is set in a tapered shape. A limit groove 525 is opened on the nut seat 541. The two ends of the second spring 544 abut against the rotating block 523 and the pump body 1, respectively. When the nut seat 541 moves towards the smooth section 521, the nut seat 541 pushes the rotating block 523 to move. The limit block 524 slips between the limit groove 525. When the nut seat 541 resets, the limit block 524 and the limit groove 525 cooperate. As the nut seat 541 moves toward the smooth section 521, it abuts against the rotating block 523 and pushes the rotating block 523 to move and rotate on the rotating section 522, causing the second spring 544 to deform under force. When the threaded rod 52 stops rotating, the second spring 544 recovers and pushes the rotating block 523 toward the threaded seat and rotates. When the limiting block 524 engages with the limiting groove 525, the rotating block 523 drives the nut seat 541 to rotate together, so that the nut seat 541 is threadedly connected to the threaded rod 52, reducing the possibility of the nut seat 541 getting stuck during the reset process.

[0043] Reference Figure 3 and Figure 5 During the startup phase, the larger clearance reduces the resistance experienced by rotor 3 as it rotates within pump chamber 2, thus lowering the torque required for the motor to drive rotor 3 and reducing power consumption during startup. Furthermore, during startup, the rotor 3 may experience some wobbling and instability due to the motor's unstable speed. The larger clearance also reduces the likelihood of rotor 3 colliding with the pump chamber 2 wall, protecting the surfaces of both and minimizing the possibility of wear, deformation, or other damage caused by collisions. In the initial pumping phase, the larger clearance facilitates the rapid discharge of large amounts of gas. As the pumping process progresses, gradually reducing the clearance increases the gas compression ratio, leading to more efficient gas extraction and improved overall pumping performance.

[0044] Reference Figure 3 and Figure 7 The drive motor 4 rotates, causing the first gear 545 and the second gear 546 to rotate, which in turn causes the threaded rod 52 to rotate as well. When the threaded rod 52 rotates, the nut seat 541 moves along the axial direction of the threaded rod 52 towards the smooth section 521, gradually reducing the gap between the rotor 3 and the inner wall of the pump chamber 2. Once the nut seat 541 reaches the smooth section 521, it stops moving. During the movement of the nut seat 541, the second spring 544 deforms under stress, and the piston rod of the hydraulic cylinder 543 gradually retracts. When the threaded rod... After rod 52 stops rotating, the second spring 544 returns to its original position, causing nut seat 541 to rotate and move to the threaded connection of threaded rod 52. The movement of nut seat 541 provides a small external force to the piston rod of hydraulic cylinder 543, which is transmitted to the piston of hydraulic cylinder 543 through hydraulic oil. Since the piston surface will generate a large thrust on the piston, it pushes the piston rod out, and sliding plate 51 is pushed to its reset position. That is, after the Roots vacuum pump starts, the gap between rotor 3 and pump chamber 2 gradually decreases, and after the Roots vacuum pump stops, the gap between rotor 3 and pump chamber 2 gradually increases and returns to its original position.

[0045] Reference Figure 3 and Figure 8 A slide rod 18 is fixedly connected to the pump body 1, through which a sliding plate 51 passes. Several limiting protrusions 19 are evenly distributed and fixedly connected along the radial direction of the slide rod 18. Elastic anti-slip plates are fixedly connected to the surfaces of the limiting protrusions 19. When the sliding plate 51 moves to the smooth section 521 of the threaded rod 52, the elastic anti-slip plates on the slide rod 18 abut against the sliding plate 51. When the sliding plate 51 moves to the position of the limiting protrusions 19 and abuts against the elastic anti-slip plates, the rubber material of the elastic anti-slip plates effectively prevents the sliding plate 51 from accidentally sliding due to external vibrations, minor vibrations generated during equipment operation, etc. This increases the stability of the position after the gap between the rotor 3 and the pump chamber 2 is adjusted.

[0046] Reference Figure 3and Figure 7 Two spur gears 21 are rotatably connected inside the pump body 1. The two spur gears 21 mesh with each other, and universal couplings 22 are coaxially and fixedly connected to each of the two spur gears 21. The other ends of the two universal couplings 22 are coaxially and fixedly connected to the corresponding rotating shafts 6. The two meshing spur gears 21 ensure the synchronicity and stability of rotation; the universal couplings 22 can adapt to changes in the position of the rotor 3, ensuring the normal rotation of the rotor 3 and reducing the possibility of transmission interruption or instability caused by changes in the position of the rotating shafts 6.

[0047] Of course, the above are just typical examples of this application. In addition, this application may have many other specific implementation methods. All technical solutions formed by equivalent substitution or equivalent transformation fall within the scope of protection claimed in this application.

Claims

1. A Roots vacuum pump that is easy to start, comprising a pump body (1) with a pump chamber (2), two rotors (3) and a drive motor (4), characterized in that: It also includes a drive assembly (5). The pump chamber (2) is tapered from one end to the other along its length. Two rotors (3) are rotatably connected inside the pump chamber (2). The two rotors (3) are tapered from one end to the other along their length. Each of the two rotors (3) is provided with a rotating shaft (6). The rotating shafts (6) are slidably connected to the pump body (1). Each rotating shaft (6) is provided with a sliding sleeve (7). The drive motor (4) is located on the pump body (1). The sliding sleeve (7) is slidably connected to the output shaft of the drive motor (4). The drive assembly (5) Used to drive the sliding of the rotating shaft (6), when the driving assembly (5) drives the two rotating shafts (6) to move, the gap between the rotor (3) and the pump chamber (2) changes; two retaining plates (8) are slidably connected in the pump chamber (2), and two grooves (9) are respectively opened on the two retaining plates (8). Thin-walled bearings (10) are respectively provided at both ends of the two rotating shafts (6) along the axial direction. The inner rings of the two thin-walled bearings (10) are respectively fixed coaxially and fixedly connected to the rotating shaft (6), and the outer rings of the two thin-walled bearings (10) are respectively slidably connected in the grooves (9) along their radial direction.

2. The Roots vacuum pump that is easy to start according to claim 1, characterized in that: The drive assembly (5) includes a sliding plate (51), a threaded rod (52), and an adjusting component (54). The sliding plate (51) is slidably connected to the pump body (1). Two sliding blocks (53) are slidably connected to the sliding plate (51). One end of each of the two rotating shafts (6) is rotatably connected to the corresponding sliding block (53). The threaded rod (52) is rotatably connected to the pump body (1). The threaded rod (52) passes through and is threadedly connected to the sliding plate (51). The adjusting component (54) is used to adjust the rotation of the sliding plate (51) on the threaded rod (52).

3. The Roots vacuum pump that is easy to start according to claim 2, characterized in that: The adjusting component (54) includes a nut seat (541), a one-way bearing (542), a hydraulic cylinder (543), and a second spring (544). The nut seat (541) is rotatably connected to the sliding plate (51). The outer ring of the one-way bearing (542) is located on the sliding plate (51), and the inner ring of the one-way bearing (542) is located on the nut seat (541). The threaded rod (52) passes through and is threadedly connected to the nut seat (541). The threaded rod (52) has a smooth section (521) and a second gear (546) is provided on the threaded rod (52). The drive motor (4) is equipped with... There is a first gear (545), and the first gear (545) and the second gear (546) are meshed together to form a gear set (547). The hydraulic cylinder (543) is fixedly connected to the pump body (1). One end of the piston rod of the hydraulic cylinder (543) is fixedly connected to the sliding plate. The second spring (544) is sleeved on the threaded rod (52). When the threaded rod (52) rotates, the nut seat (541) cannot rotate and moves towards the smooth section (521). The gap between the rotor (3) and the inner wall of the pump chamber (2) gradually decreases. The second spring (544) deforms and the piston rod of the hydraulic cylinder (543) retracts.

4. The Roots vacuum pump that is easy to start according to claim 3, characterized in that: The threaded rod (52) is provided with a rotating section (522), and a rotating block (523) is threadedly connected to the rotating section (522). A limiting block (524) is provided on the rotating block (523), and the limiting block (524) is arranged in a tapered shape. A limiting groove (525) is provided on the nut seat (541). The two ends of the second spring (544) abut against the rotating block (523) and the pump body (1) respectively. When the nut seat (541) moves towards the smooth section (521), the nut seat (541) pushes the rotating block (523) to move. The limiting block (524) slips between itself and the limiting groove (525). When the nut seat (541) resets, the limiting block (524) cooperates with the limiting groove (525).

5. A Roots vacuum pump that is easy to start according to claim 2, characterized in that: The pump body (1) is provided with a slide rod (18), through which a sliding plate (51) passes. The slide rod (18) is provided with a plurality of limiting protrusions (19), and the surface of the plurality of limiting protrusions (19) is provided with elastic anti-slip sheets. When the sliding plate (51) moves to the smooth section (521), the elastic anti-slip sheets abut against the sliding plate (51).

6. A Roots vacuum pump that is easy to start according to claim 2, characterized in that: The pump body (1) is rotatably connected to two spur gears (21), which mesh with each other. Each of the two spur gears (21) is provided with a universal coupling (22), and the other end of each of the two universal couplings (22) is fixedly connected to the rotating shaft (6).

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