Screw vacuum pump and control method thereof

Abstract

The invention provides a screw vacuum pump and a control method thereof, the screw vacuum pump comprises a first screw, a second screw and at least two driving motors, the axis of the first screw and the axis of the second screw are parallel to each other, and the first screw and the second screw are in transmission connection; the at least two driving motors are respectively in transmission connection with the first screw rod and the second screw rod, or the at least two driving motors are respectively in transmission connection with two ends of the first screw rod, or the at least two driving motors are respectively in transmission connection with two ends of the second screw rod. According to the invention, the influence of motor faults on production continuity can be avoided, so that the production efficiency is guaranteed.

Description

Technical Field

[0001] This invention belongs to the field of vacuum pump manufacturing technology, specifically relating to a screw vacuum pump and its control method. Background Technology

[0002] Vacuum pumps are essential equipment in industrial production. Screw vacuum pumps, with their wide pumping speed range and compact structure, are widely used in industries such as photovoltaics, semiconductors, LCD panels, and chemicals. Currently, all existing screw vacuum pumps use a single-motor direct-drive method. With this method, in practical operation, when the motor fails, the machine needs to be stopped for repair or replacement, thus affecting the continuity of production and compromising production efficiency. Summary of the Invention

[0003] This invention provides a screw vacuum pump and its control method, which can avoid the impact of motor failure on the continuity of production, thereby ensuring production efficiency.

[0004] A screw vacuum pump includes a first screw, a second screw, and at least two drive motors, wherein the axes of the first screw and the second screw are parallel to each other and are connected in a transmission manner;

[0005] At least two of the drive motors are respectively driven to the first screw and the second screw, or at least two drive motors are respectively driven to the two ends of the first screw, or at least two drive motors are respectively driven to the two ends of the second screw.

[0006] Preferably, the number of drive motors is four, and along the extension direction of the first screw and the second screw, the two ends of the first screw are the first left end and the first right end, respectively, and the two ends of the second screw are the second left end and the second right end, respectively.

[0007] The four drive motors are a first motor, a second motor, a third motor, and a fourth motor. The first motor is driven and connected to the first left end, the second motor is driven and connected to the second left end, the third motor is driven and connected to the first right end, and the fourth motor is driven and connected to the second right end.

[0008] Preferably, it also includes a first connecting mechanism, a second connecting mechanism, a third connecting mechanism, and a fourth connecting mechanism;

[0009] The first connecting mechanism includes a first coupling A, a first coupling B, and a first threaded fastener. The first coupling A is fixedly connected to the first motor, and the first coupling B is fixedly connected to the first left end. A first through hole A is provided on the first coupling A, and a first through hole B is provided on the first coupling B. The first threaded fastener passes through the first through hole A and the first through hole B to fix the first coupling A and the first coupling B together.

[0010] The second connecting mechanism includes a second coupling A, a second coupling B, and a second threaded fastener. The second coupling A is fixedly connected to the second motor, and the second coupling B is fixedly connected to the second left end. A second through hole A is provided on the second coupling A, and a second through hole B is provided on the second coupling B. The second threaded fastener passes through the second through hole A and the second through hole B to fix the second coupling A and the second coupling B together.

[0011] The third connecting mechanism includes a third coupling A, a third coupling B, and a third threaded fastener. The third coupling A is fixedly connected to the third motor, and the third coupling B is fixedly connected to the first right end. A third through hole A is provided on the third coupling A, and a third through hole B is provided on the third coupling B. The third threaded fastener passes through the third through hole A and the third through hole B to fix the third coupling A and the third coupling B together.

[0012] The fourth connecting mechanism includes a fourth coupling A, a fourth coupling B, and a fourth threaded fastener. The fourth coupling A is fixedly connected to the fourth motor, and the fourth coupling B is fixedly connected to the second right end. A fourth through hole A is provided on the fourth coupling A, and a fourth through hole B is provided on the fourth coupling B. The fourth threaded fastener passes through the fourth through hole A and the fourth through hole B to fix the fourth coupling A and the fourth coupling B together.

[0013] Preferably, the number of the first through holes A is at least two, and the at least two first through holes A are arranged in a circular array. The number of the first through holes B is equal to the number of the first through holes A and corresponds one-to-one. The number of the first threaded fasteners is equal to the number of the first through holes A and corresponds one-to-one.

[0014] The number of the second through holes A is at least two, and the at least two second through holes A are arranged in a circular array. The number of the second through holes B is equal to the number of the second through holes A, and they correspond one-to-one. The number of the second threaded fasteners is equal to the number of the second through holes A, and they correspond one-to-one.

[0015] The number of the third through holes A is at least two, and the at least two third through holes A are arranged in a circular array. The number of the third through holes B is equal to the number of the third through holes A, and they correspond one-to-one. The number of the third threaded fasteners is equal to the number of the third through holes A, and they correspond one-to-one.

[0016] The number of the fourth through holes A is at least two, and the at least two fourth through holes A are arranged in a circular array. The number of the fourth through holes B is equal to the number of the fourth through holes A and corresponds one-to-one. The number of the fourth threaded fasteners is equal to the number of the fourth through holes A and corresponds one-to-one.

[0017] Preferably, it also includes a first gear and a second gear that mesh with each other, wherein a first through hole C is provided on the first gear and a second through hole C is provided on the second gear;

[0018] The first gear is located between the first coupling A and the first coupling B, and is sleeved on the first threaded fastener through the first through hole C. The second gear is located between the second coupling A and the second coupling B, and is sleeved on the second threaded fastener through the second through hole C.

[0019] Preferably, it also includes a third gear and a fourth gear that mesh with each other, wherein a third through hole C is provided on the third gear and a fourth through hole C is provided on the fourth gear;

[0020] The third gear is located between the third coupling A and the third coupling B, and is fitted onto the third threaded fastener through the third through hole C. The fourth gear is located between the fourth coupling A and the fourth coupling B, and is fitted onto the fourth threaded fastener through the fourth through hole C.

[0021] Preferably, it also includes a controller, a housing, and an intake pipe;

[0022] Both the first screw and the second screw are disposed within the housing, which has an air inlet. One end of the air inlet pipe is connected to the air inlet, and the other end can be connected to an external target device so that fluid in the external target device can enter the housing through the air inlet pipe.

[0023] An intake valve is provided on the intake pipe. The controller is electrically connected to the intake valve and the drive motor respectively to control the working state of the intake valve and control the operation of the drive motor according to the working state of the intake valve.

[0024] Preferably, a dust concentration detection device electrically connected to the controller is provided inside the air intake pipe;

[0025] The dust concentration detection device detects the dust concentration in the gas entering the housing through the air inlet pipe in real time and sends the information to the controller. The controller controls the drive motor to work based on the fluid viscosity information.

[0026] A control method for a screw vacuum pump, using the screw vacuum pump described above, wherein the screw vacuum pump includes a controller, a housing, and an inlet pipe;

[0027] The control method for this screw vacuum pump includes the following steps:

[0028] S100, the controller controls the speed of the drive motor to increase from 0 to V1;

[0029] S200. When the speed of the drive motor reaches V1, the controller controls the current of the drive motor to I.

[0030] S300: The controller controls the intake valve to open and controls the speed of the drive motor to change from V1 to V2.

[0031] S400: The controller controls the intake valve to close and controls the speed of the drive motor to change from V2 to V1;

[0032] Where V1 is the set speed, I is the minimum current that the motor can maintain at speed V1, and V2 is the operating speed of the motor.

[0033] Preferably, when a dust concentration detection device electrically connected to the controller is installed inside the air intake pipe,

[0034] Step S300 includes: the controller adjusting the value of V2 based on the dust concentration information detected by the dust concentration detection device.

[0035] The screw vacuum pump provided by the present invention employs a technical solution in which at least two drive motors are respectively connected to the first screw and the second screw, or at least two drive motors are respectively connected to the two ends of the first screw, or at least two drive motors are respectively connected to the two ends of the second screw. This solution enables the other drive motors to continue driving the screw vacuum pump when one drive motor fails, avoiding disruption to production continuity due to motor failure and thus ensuring production efficiency. Attached Figure Description

[0036] Figure 1 This is a schematic diagram of the screw vacuum pump embodiment in Example 1;

[0037] Figure 2 yes Figure 1 A schematic diagram of the connection status of the first connecting mechanism in the diagram;

[0038] Figure 3 yes Figure 1 K-direction diagram;

[0039] Figure 4 yes Figure 3 Circuit diagram;

[0040] Figure 5 This is a flowchart of the screw vacuum pump control method in Example 3.

[0041] The reference numerals in the figure are as follows:

[0042] 1-First screw; 2-Second screw; 3-Drive motor; 4-First left end; 5-First right end; 6-Second left end; 7-Second right end; 8-First motor; 9-Second motor; 10-Third motor; 11-Fourth motor; 12-First connecting mechanism; 13-Second connecting mechanism; 14-Third connecting mechanism; 15-Fourth connecting mechanism; 16-First coupling A; 17-First coupling B; 18-First threaded fastener; 19-First through hole A; 20-First through hole B; 21-First gear; 22-Second gear; 23-First through hole C; 24-Third gear; 25-Fourth gear; 26-Controller; 27-Housing; 28-Inlet pipe; 29-Inlet hole; 30-Inlet valve; 31-Dust concentration detection device. Detailed Implementation

[0043] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below in conjunction with specific embodiments and corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0044] Example 1

[0045] like Figure 1 As shown, a screw vacuum pump includes a first screw 1, a second screw 2, and at least two drive motors 3. The axes of the first screw 1 and the second screw 2 are parallel to each other and are connected in a driving manner. The at least two drive motors 3 are respectively connected to the first screw 1 and the second screw 2, or respectively connected to the two ends of the first screw 1, or respectively connected to the two ends of the second screw 2. With this technical solution, when one drive motor 3 fails, the other drive motors 3 will continue to operate the screw vacuum pump, avoiding disruption to production continuity due to the failure of one drive motor 3, thereby ensuring production efficiency.

[0046] As a preferred implementation scheme, such as Figure 1 As shown, there are four drive motors 3. Along the extension direction of the first screw 1 and the second screw 2, the two ends of the first screw 1 are the first left end 4 and the first right end 5, respectively, and the two ends of the second screw 2 are the second left end 6 and the second right end 7, respectively. The four drive motors 3 are designated as first motor 8, second motor 9, third motor 10, and fourth motor 11. First motor 8 is driven to the first left end 4, second motor 9 is driven to the second left end 6, third motor 10 is driven to the first right end 5, and fourth motor 11 is driven to the second right end 7. In this way, first motor 8 and third motor 10 can drive the first screw 1 from both ends respectively. Compared to driving the first screw 1 from only one end with a single motor, this reduces the vibration of the first screw 1, thereby reducing the noise generated by the first screw 1. Similarly, by driving the second screw 2 from both ends with second motor 9 and fourth motor 11 respectively, the vibration of the second screw 2 can also be reduced, thereby reducing the noise of the second screw 2.

[0047] In actual production, such as Figure 1 As shown, it also includes a first connecting mechanism 12, a second connecting mechanism 13, a third connecting mechanism 14, and a fourth connecting mechanism 15. Among them, as... Figure 2 As shown, the first connecting mechanism 12 includes a first coupling A16, a first coupling B17, and a first threaded fastener 18. The first coupling A16 is fixedly connected to the first motor 8, and the first coupling B17 is fixedly connected to the first left end 4. A first through hole A19 is provided on the first coupling A16, and a first through hole B20 is provided on the first coupling B17. The first threaded fastener 18 passes through the first through hole A19 and the first through hole B20 to fix the first coupling A16 and the first coupling B17 together. This ensures the reliability of the connection between the first motor 8 and the first left end 4. It should be noted that in specific manufacturing, the number of first through holes A19 is at least two, and these at least two first through holes A19 are arranged in a circular array. The number of first through holes B20 is equal to the number of first through holes A19 and corresponds one-to-one. The number of first threaded fasteners 18 is equal to the number of first through holes A19 and corresponds one-to-one.

[0048] The second connecting mechanism 13 includes a second coupling A (not shown), a second coupling B (not shown), and a second threaded fastener (not shown). The second coupling A is fixedly connected to the second motor 9, and the second coupling B is fixedly connected to the second left end 6. A second through hole A (not shown) and a second through hole B (not shown) are provided on the second coupling A and the second coupling B, respectively. The second threaded fastener passes through the second through hole A and the second through hole B to fix the second coupling A and the second coupling B together. This ensures the reliability of the connection between the second motor 9 and the second left end 6. The specific connection method of the second coupling A and the second coupling B can be found in [reference needed]. Figure 2 It should be noted that in the specific manufacturing process, there are at least two second through holes A, and the at least two second through holes A are arranged in a circular array. The number of second through holes B is equal to the number of second through holes A, and they correspond one-to-one. The number of second threaded fasteners is equal to the number of second through holes A, and they correspond one-to-one.

[0049] The third connecting mechanism 14 includes a third coupling A (not shown), a third coupling B (not shown), and a third threaded fastener (not shown). The third coupling A is fixedly connected to the third motor 10, and the third coupling B is fixedly connected to the first right end 5. A third through hole A (not shown) is provided on the third coupling A, and a third through hole B (not shown) is provided on the third coupling B. The third threaded fastener passes through the third through holes A and B to fix the third coupling A and the third coupling B together. This ensures the reliability of the connection between the third motor 10 and the first right end 5. The specific connection method of the third coupling A and the third coupling B can be found in [reference needed]. Figure 2 It should be noted that in the specific manufacturing process, there are at least two third through holes A, and the at least two third through holes A are arranged in a circular array. The number of third through holes B is equal to the number of third through holes A, and they correspond one-to-one. The number of third threaded fasteners is equal to the number of third through holes A, and they correspond one-to-one.

[0050] The fourth connecting mechanism 15 includes a fourth coupling A (not shown), a fourth coupling B (not shown), and a fourth threaded fastener (not shown). The fourth coupling A is fixedly connected to the fourth motor 11, and the fourth coupling B is fixedly connected to the second right end 7. A fourth through hole A (not shown) is provided on the fourth coupling A, and a fourth through hole B (not shown) is provided on the fourth coupling B. The fourth threaded fastener passes through the fourth through hole A and the fourth through hole B to fix the fourth coupling A and the fourth coupling B together. This ensures the reliability of the connection between the fourth motor 11 and the second right end 7. The specific connection method of the fourth coupling A and the fourth coupling B can be found in [reference needed]. Figure 2It should be noted that in the specific manufacturing process, there are at least two fourth through holes A, and the at least two fourth through holes A are arranged in a circular array. The number of fourth through holes B is equal to the number of fourth through holes A, and they correspond one-to-one. The number of fourth threaded fasteners is equal to the number of fourth through holes A, and they correspond one-to-one.

[0051] Preferably, such as Figure 1 , 2 It also includes a first gear 21 and a second gear 22 that mesh with each other. The first gear 21 has a first through hole C23, and the second gear 22 has a second through hole C (not shown in the figure). The first gear 21 is located between the first coupling A16 and the first coupling B17, and is fitted onto the first threaded fastener 18 through the first through hole C23. The second gear 22 is located between the second coupling A and the second coupling B, and is fitted onto the second threaded fastener through the second through hole C. The specific installation method of the second gear 22 can be found in [reference needed]. Figure 2 This technical solution allows for the limitation of the distance between the first screw 1 and the second screw 2 via the first gear 21 and the second gear 22, preventing them from approaching each other in the direction perpendicular to their axes. It also establishes a transmission connection between them. When the drive motor 3 connected to the first screw 1 malfunctions, the drive motor 3 connected to the second screw 2 can drive the first screw 1 to rotate via the second screw 2, the second gear 22, and the first gear 21 in one operation, and vice versa. It should be noted that when there are at least two first through holes A19, the number of first through holes C23 is equal to the number of first through holes A19, and they correspond one-to-one. Similarly, when there are at least two second through holes A, the number of second through holes C is equal to the number of second through holes A, and they correspond one-to-one.

[0052] Furthermore, such as Figure 1 As shown, it also includes a third gear 24 and a fourth gear 25 that mesh with each other. The third gear 24 has a third through hole C, and the fourth gear 25 has a fourth through hole C. The third gear 24 is located between the third coupling A and the third coupling B, and is fitted onto the third threaded fastener through the third through hole C. The fourth gear 25 is located between the fourth coupling A and the fourth coupling B, and is fitted onto the fourth threaded fastener through the fourth through hole C. This further ensures the relative position between the first screw 1 and the second screw 2. The specific installation methods for the third gear 24 and the fourth gear 25 can be found in [reference needed]. Figure 2 .

[0053] Example 2

[0054] Based on Example 1, such as Figure 3 , 4As shown, it also includes a controller 26, a housing 27, and an air inlet pipe 28. The first screw 1 and the second screw 2 are both housed within the housing 27. In actual manufacturing, the drive motor 3 can be fixedly connected to the housing 27. The housing 27 has an air inlet hole 29, and one end of the air inlet pipe 28 is connected to the air inlet hole 29, while the other end can be connected to an external target device, allowing fluid from the external target device to enter the housing 27 through the air inlet pipe 28. The external target device referred to here is the device used by the screw vacuum pump to evacuate the air. An air inlet valve 30 is provided on the air inlet pipe 28. The controller 26 is electrically connected to both the air inlet valve 30 and the drive motor 3, controlling the operating state of the air inlet valve 30 and simultaneously controlling the operation of the drive motor 3 based on the operating state of the air inlet valve 30.

[0055] The intake valve 30 is initially closed. Upon startup, the controller 26 controls the drive motors 3 (including the first motor 8, second motor 9, third motor 10, and fourth motor 11) to rapidly increase speed using a synchronization algorithm. The drive motors 3 drive the first screw 1 and the second screw 2 to rotate. When the speed reaches the set speed, the controller 26 controls the current of the drive motors 3 to decrease to the minimum value needed to maintain the speed, thus reducing energy consumption. During operation, the controller 26 controls the intake valve 30 to open, allowing gas from the external target device to enter the housing 27 through the intake pipe 28. Under the control of the controller 26, the drive motors 3 operate at a higher speed to ensure work efficiency. After operation, the controller 26 controls the intake valve 30 to close, and simultaneously controls the speed of the drive motors 3 to return to the set speed.

[0056] Furthermore, such as Figure 3 , 4 As shown, a dust concentration detection device 31, electrically connected to the controller 26, is installed inside the air intake pipe 28. The dust concentration detection device 31 detects the dust concentration in the gas entering the housing 27 through the air intake pipe 28 in real time and sends this information to the controller 26. The controller 26 then controls the drive motor 3 to operate based on this dust concentration information. In this way, the controller 26 can adjust the operating speed of the drive motor 3 according to the actual situation of the gas entering the housing 27, thus reducing energy consumption while ensuring working efficiency.

[0057] Example 3

[0058] A control method for a screw vacuum pump, using the screw vacuum pump described in Example 2.

[0059] like Figure 5 As shown, the control method of this screw vacuum pump includes the following steps:

[0060] S100, the controller controls the speed of the drive motor to increase from 0 to V1;

[0061] S200. When the speed of the drive motor reaches V1, the controller controls the current of the drive motor to I.

[0062] S300: The controller controls the intake valve to open and controls the speed of the drive motor to change from V1 to V2.

[0063] S400: The controller closes the intake valve and changes the drive motor speed from V2 to V1; where V1 is the set speed (which can be set by the operator according to actual conditions), I is the minimum current required for the motor to maintain speed V1, and V2 is the motor's operating speed (the speed that ensures the efficiency of the screw vacuum pump). This technical solution reduces energy consumption while maintaining working efficiency.

[0064] Furthermore, when a dust concentration detection device electrically connected to the controller is installed inside the intake pipe,

[0065] Step S300 includes: the controller adjusting the value of V2 based on the dust concentration information detected by the dust concentration detection device. This reduces energy consumption while ensuring working efficiency.

[0066] The above embodiments enable the present invention to avoid the impact of motor failure on the continuity of production, thereby ensuring production efficiency, while reducing energy consumption while ensuring work efficiency.

[0067] It will be readily understood by those skilled in the art that the aforementioned advantageous methods can be freely combined and superimposed without conflict.

[0068] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention. The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the protection scope of the present invention.

Claims

1. A screw vacuum pump, characterized in that: It includes a first screw (1), a second screw (2) and at least two drive motors (3), wherein the axis of the first screw (1) and the axis of the second screw (2) are parallel to each other and are connected in transmission; At least two of the drive motors (3) are respectively connected to the first screw (1) and the second screw (2), or at least two drive motors (3) are respectively connected to the two ends of the first screw (1), or at least two drive motors (3) are respectively connected to the two ends of the second screw (2).

2. The screw vacuum pump according to claim 1, characterized in that: The number of drive motors (3) is four. Along the extension direction of the first screw (1) and the second screw (2), the two ends of the first screw (1) are the first left end (4) and the first right end (5), and the two ends of the second screw (2) are the second left end (6) and the second right end (7). The four drive motors (3) are a first motor (8), a second motor (9), a third motor (10), and a fourth motor (11). The first motor (8) is driven to the first left end (4), the second motor (9) is driven to the second left end (6), the third motor (10) is driven to the first right end (5), and the fourth motor (11) is driven to the second right end (7).

3. The screw vacuum pump according to claim 2, characterized in that: It also includes a first connecting mechanism (12), a second connecting mechanism (13), a third connecting mechanism (14), and a fourth connecting mechanism (15); The first connecting mechanism (12) includes a first coupling A (16), a first coupling B (17) and a first threaded fastener (18). The first coupling A (16) is fixedly connected to the first motor (8), and the first coupling B (17) is fixedly connected to the first left end (4). A first through hole A (19) is provided on the first coupling A (16), and a first through hole B (20) is provided on the first coupling B (17). The first threaded fastener (18) passes through the first through hole A (19) and the first through hole B (20) to fix the first coupling A (16) and the first coupling B (17) together. The second connecting mechanism (13) includes a second coupling A, a second coupling B, and a second threaded fastener. The second coupling A is fixedly connected to the second motor (9), and the second coupling B is fixedly connected to the second left end (6). A second through hole A is provided on the second coupling A, and a second through hole B is provided on the second coupling B. The second threaded fastener passes through the second through hole A and the second through hole B to fix the second coupling A and the second coupling B together. The third connecting mechanism (14) includes a third coupling A, a third coupling B and a third threaded fastener. The third coupling A is fixedly connected to the third motor (10), and the third coupling B is fixedly connected to the first right end (5). A third through hole A is provided on the third coupling A, and a third through hole B is provided on the third coupling B. The third threaded fastener passes through the third through hole A and the third through hole B to fix the third coupling A and the third coupling B together. The fourth connecting mechanism (15) includes a fourth coupling A, a fourth coupling B, and a fourth threaded fastener. The fourth coupling A is fixedly connected to the fourth motor (11), and the fourth coupling B is fixedly connected to the second right end (7). A fourth through hole A is provided on the fourth coupling A, and a fourth through hole B is provided on the fourth coupling B. The fourth threaded fastener passes through the fourth through hole A and the fourth through hole B to fix the fourth coupling A and the fourth coupling B together.

4. The screw vacuum pump according to claim 3, characterized in that: The number of the first through holes A (19) is at least two, and the at least two first through holes A (19) are arranged in a circular array. The number of the first through holes B (20) is equal to the number of the first through holes A (19) and they correspond one-to-one. The number of the first threaded fasteners (18) is equal to the number of the first through holes A (19) and they correspond one-to-one. The number of the second through holes A is at least two, and the at least two second through holes A are arranged in a circular array. The number of the second through holes B is equal to the number of the second through holes A, and they correspond one-to-one. The number of the second threaded fasteners is equal to the number of the second through holes A, and they correspond one-to-one. The number of the third through holes A is at least two, and the at least two third through holes A are arranged in a circular array. The number of the third through holes B is equal to the number of the third through holes A, and they correspond one-to-one. The number of the third threaded fasteners is equal to the number of the third through holes A, and they correspond one-to-one. The number of the fourth through holes A is at least two, and the at least two fourth through holes A are arranged in a circular array. The number of the fourth through holes B is equal to the number of the fourth through holes A and corresponds one-to-one. The number of the fourth threaded fasteners is equal to the number of the fourth through holes A and corresponds one-to-one.

5. The screw vacuum pump according to claim 3, characterized in that: It also includes a first gear (21) and a second gear (22) that mesh with each other, with a first through hole C (23) provided on the first gear (21) and a second through hole C provided on the second gear (22); The first gear (21) is located between the first coupling A (16) and the first coupling B (17) and is sleeved on the first threaded fastener (18) through the first through hole C (23). The second gear (22) is located between the second coupling A and the second coupling B and is sleeved on the second threaded fastener through the second through hole C.

6. The screw vacuum pump according to claim 3, characterized in that: It also includes a third gear (24) and a fourth gear (25) that mesh with each other, wherein a third through hole C is provided on the third gear (24) and a fourth through hole C is provided on the fourth gear (25); The third gear (24) is located between the third coupling A and the third coupling B, and is sleeved on the third threaded fastener through the third through hole C. The fourth gear (25) is located between the fourth coupling A and the fourth coupling B, and is sleeved on the fourth threaded fastener through the fourth through hole C.

7. The screw vacuum pump according to any one of claims 1 to 6, characterized in that: It also includes a controller (26), a housing (27), and an air intake pipe (28); The first screw (1) and the second screw (2) are both disposed inside the housing (27). The housing (27) has an air inlet (29). One end of the air inlet pipe (28) is connected to the air inlet (29), and the other end can be connected to an external target device so that the fluid in the external target device can enter the housing (27) through the air inlet pipe (28). An intake valve (30) is provided on the intake pipe (28). The controller (26) is electrically connected to the intake valve (30) and the drive motor (3) respectively, to control the working state of the intake valve (30) and control the drive motor (3) to work according to the working state of the intake valve (30).

8. The screw vacuum pump according to claim 7, characterized in that: A dust concentration detection device (31) electrically connected to the controller (26) is installed inside the air intake pipe (28); The dust concentration detection device (31) detects the dust concentration information in the gas entering the housing (27) through the air inlet pipe (28) in real time, and sends the information to the controller (26). The controller (26) controls the drive motor (3) to work according to the dust concentration information.

9. A control method for a screw vacuum pump, characterized in that: Using the screw vacuum pump as described in claim 7 or 8, the steps include: The controller controls the speed of the drive motor to increase from 0 to a speed of V1; When the speed of the drive motor reaches V1, the controller controls the current of the drive motor to I; The controller controls the intake valve to open and controls the speed of the drive motor to change from V1 to V2; the controller controls the intake valve to close and controls the speed of the drive motor to change from V2 to V1. Where V1 is the set speed, I is the minimum current that the motor can maintain at speed V1, and V2 is the operating speed of the motor.

10. The control method for a screw vacuum pump according to claim 9, characterized in that: When a dust concentration detection device electrically connected to the controller is installed inside the air intake pipe... The controller controls the intake valve to open and controls the speed of the drive motor to change from V1 to V2, including: the controller adjusts the value of V2 according to the dust concentration information detected by the dust concentration detection device.

Images