Vacuum swing valve and vacuum pressure control system

Abstract

The invention discloses a vacuum swing valve and a vacuum pressure control system. The vacuum swing valve comprises a valve body, a valve plate, a valve rod, a stepping motor, a coupler and an encoder. The valve body is provided with a channel for fluid to pass through. The valve plate is rotatably arranged in the valve body and used for adjusting the opening degree of the channel. The valve rod rotatably penetrates into the valve body and is fixedly connected with the valve plate. The stepping motor is fixed outside the valve body and connected with the valve rod through a coupler. The encoder comprises a grating part fixedly arranged on the valve rod in a sleeving mode and a sensing part fixed relative to the valve body and used for sensing the grating part. When the stepping motor drives the valve plate to rotate in the valve body through the valve rod, the sensing part of the encoder can sense the movement of the grating part relative to the sensing part, and motion parameters of the valve plate are obtained based on the sensing result. According to the vacuum swing valve, the control dead zone of an existing vacuum swing valve is eliminated, the control precision of the vacuum swing valve is improved, and the stability of the vacuum degree of a vacuum system is enhanced.

Description

Technical Field

[0001] Embodiments of the present invention relate to the technical field of vacuum swing valves, and more specifically, the present invention relates to a vacuum swing valve and a vacuum pressure control system. Background Art

[0002] In the field of vacuum technology, the vacuum swing valve plays a vital role. As the core component of fluid control, it widely connects and regulates the operation of various components in the vacuum system. The vacuum swing valve uses the swinging action of the valve plate to accurately manage the flow state of the fluid. It has a compact design, good vibration suppression effect, smooth opening and closing process, and can effectively prevent the generation of particulate matter, ensuring the accuracy of fluid control and the cleanliness of the system. More importantly, even the slightest swing of the valve plate will have a significant impact on the vacuum degree of the vacuum system connected to it, highlighting its key role in maintaining stable system performance.

[0003] However, current vacuum swing valve technology still faces significant challenges in terms of precision control. The traditional vacuum swing valve structure usually includes a valve body for a channel through which fluid passes, a valve plate that can rotate in the valve body to adjust the degree of opening and closing of the channel, and a valve stem that passes through the valve body and is fixedly connected to the valve plate. In order to further improve the adjustment accuracy of the valve plate opening, the vacuum swing valve also integrates a motor and fan gears. The gears on the output shaft of the motor mesh with the fan gears, and then the power of the motor is transmitted to the valve plate connected to the valve stem through the tooth meshing method through the valve stem connected to the fan gears to achieve the purpose of precise adjustment.

[0004] Nevertheless, even if the sector gears and the motor output shaft are processed by high-precision manufacturing processes, after long-term operation, natural factors such as mechanical wear will still cause the meshing state between the two to gradually deviate from the ideal state, thus causing the problem of control dead zone. Specifically, when the motor continues to rotate, the valve stem may remain stationary due to poor meshing. This phenomenon directly hinders the ability of the vacuum swing valve to achieve precise adjustment, seriously weakens the stability of the vacuum system's vacuum degree, and has a significant impact on the overall performance of the system. Summary of the invention

[0005] In order to solve one or more of the technical problems mentioned above, the present invention provides a vacuum swing valve and a vacuum pressure control system, which eliminate the control dead zone of the vacuum swing valve in the prior art, improve the control accuracy of the vacuum swing valve, and enhance the stability of the vacuum degree of the vacuum system.

[0006] According to a first aspect of the present invention, there is provided a vacuum swing valve, comprising:

[0007] a valve body having a passage for fluid to pass therethrough;

[0008] a valve plate rotatably disposed in the valve body and used to adjust the opening of the channel;

[0009] A valve stem, which is rotatably inserted into the valve body and fixedly connected to the valve plate;

[0010] A stepper motor is fixed outside the valve body and connected to the valve stem through a coupling; and

[0011] An encoder, comprising a grating portion fixedly sleeved on the valve stem, and a sensing portion fixed relative to the valve body and used to sense the grating portion;

[0012] When the stepper motor drives the valve plate to rotate in the valve body through the valve stem, the sensing portion of the encoder can sense the movement of the grating portion relative to it, and obtain the movement parameters of the valve plate based on the sensing result.

[0013] The vacuum swing valve provided in this embodiment directly transmits the strong driving force of the stepper motor to the valve plate through the precise cooperation of the coupling and the valve stem, drives the valve plate to rotate flexibly in the valve body, and then accurately controls the opening of the channel. Among them, this vacuum swing valve abandons the traditional indirect tooth meshing transmission method (that is, the motor power is first transmitted to the fan teeth, and then the fan teeth drive the valve plate to rotate), and instead adopts a direct transmission method (the valve stem and the stepper motor are directly connected through a coupling), eliminating the problem of control dead zone due to the meshing of the motor and the fan teeth (due to mechanical wear, the stepper motor rotates when the teeth are meshed with the fan teeth, but the fan teeth cannot be driven to rotate by the teeth), significantly improving the accuracy of the vacuum swing valve, and thus enhancing the stability of the vacuum degree of the vacuum system. In addition, the grating part of the encoder is cleverly fixed on the valve stem. This design cleverly avoids the cumulative error that is easy to produce in traditional mechanical transmission, so that the sensing part of the encoder can directly sense the rotation dynamics of the valve stem in the valve body in real time, thereby more accurately reflecting the opening state of the valve plate, and solving the problem of control dead zone that may exist between the encoder and the valve stem. Furthermore, the accuracy of each step of the stepper motor is due to the precise control of the electronic device, and there is no error accumulation, which brings higher positioning accuracy to the drive of the vacuum swing valve, ensures the ultimate precision of position control, and perfectly meets the high requirements for vacuum swing valves in vacuum environments. The tacit cooperation of the stepper motor, coupling and encoder has jointly created the vacuum swing valve's ability to accurately adjust the channel opening in the vacuum system, fully meeting the stringent requirements of high-precision fluid control.

[0014] Furthermore, the coupling includes a first connector fixedly mounted on the output shaft of the stepper motor, a second connector fixedly mounted on the valve stem and interlocked with the first connector, and an elastic buffer disposed at the joint between the first connector and the second connector.

[0015] Further, the first connecting body and the second connecting body are made of steel or titanium alloy, and the elastic buffer is made of rubber or latex.

[0016] Further, the vacuum swing valve further includes a fixing seat for fixedly connecting the stepping motor and the valve body. The fixing seat has an inner cavity for accommodating the valve stem, the coupling, the encoder, and the output shaft of the stepping motor.

[0017] Further, the inner cavity has a positioning step, and the valve stem has a positioning shoulder that abuts against the positioning step, so that the positioning step can prevent the valve stem from withdrawing from the valve body through the positioning shoulder that abuts against it.

[0018] Further, the valve stem and the valve plate are fixed by fastening bolts.

[0019] Further, one of the valve stem and the valve plate is provided with a positioning groove, and the other of the two is provided with a positioning pin that cooperates with the positioning groove.

[0020] According to the second aspect of the present invention, it provides a vacuum pressure control system including the vacuum swing valve.

[0021] In the vacuum pressure control system provided in this embodiment, the vacuum swing valve eliminates the control dead zone between the stepping motor and the sector gear through a direct drive method, improving the accuracy and stability of the transmission. This helps the vacuum pressure control system reduce fluctuations when maintaining the vacuum degree and improve the overall stability of the vacuum pressure control system. The vacuum swing valve utilizes the high-precision angle control of the stepping motor and the direct induction of the encoder on the rotational movement of the valve stem to achieve precise adjustment of the channel opening degree, enabling the vacuum pressure control system to more accurately control the vacuum degree and meet the requirements of high-precision fluid control.

[0022] Further, the vacuum pressure control system further includes a control unit that is electrically connected to the stepping motor and the encoder of the vacuum swing valve and controls the stepping motor based on the motion parameters through a PID algorithm.

[0023] Further, the PID algorithm includes the following formula:

[0024] e = R(t) - r(t)

[0025]

[0026] where u is the pulse signal for controlling the stepping motor; e is the deviation signal; K P is the proportionality coefficient; T I is the integral time constant; T Dis the differential time constant; u 0 is the control constant; t is the time; R(t) is the output signal of the encoder, including the actual angle of the valve plate in the valve body; r(t) is the expected angle of the valve plate in the valve body given by the control unit. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] By referring to the accompanying drawings and reading the following detailed description, the above and other objects, features and advantages of the exemplary embodiments of the present invention will become readily understood. In the drawings, several embodiments of the present invention are shown in an exemplary rather than restrictive manner, and the same or corresponding reference numerals represent the same or corresponding parts, wherein:

[0028] Figure 1 shows a top view of the vacuum swing valve provided by an embodiment of the present invention;

[0029] Figure 2 shows Figure 1 a cross-sectional view taken along the A-A direction in

[0030] Figure 3 shows an exploded schematic view of the coupling provided by an embodiment of the present invention;

[0031] Figure 4 shows a structural schematic view of the valve plate and the valve stem provided by an embodiment of the present invention.

[0032] 1. Valve body; 11. Channel;

[0033] 2. Valve plate; 21. Positioning groove;

[0034] 3. Valve stem; 31. Positioning shoulder; 32. Positioning pin;

[0035] 4. Stepper motor; 41. Output shaft;

[0036] 5. Coupling; 51. First connecting body; 52. Second connecting body; 53. Elastic buffer;

[0037] 6. Encoder; 61. Grating part; 62. Inductive part;

[0038] 7. Fixed seat; 71. Inner cavity; 711. Positioning step; 712. First chamber; 713. Second chamber;

[0039] 8. Fixed bolt. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0040] The following will clearly and completely describe the technical solutions in the embodiments of the present disclosure with reference to the accompanying drawings in the embodiments of the present disclosure. Obviously, the described embodiments are part of the embodiments of the present disclosure, rather than all of the embodiments. All other embodiments obtained by those skilled in the art based on the embodiments in the present disclosure without creative efforts belong to the scope of protection of the present disclosure.

[0041] Figure 1 Fig. 4 shows a top view of the vacuum swing valve provided in this embodiment. Figure 2 shows Figure 1 a cross-sectional view taken along the line A-A in Fig. 4. As Figure 1 and Figure 2 shown, this embodiment provides a vacuum swing valve, which includes a valve body 1, a valve plate 2, a valve stem 3, a stepping motor 4, and an encoder 6. A passage 11 for fluid to pass through is provided on the valve body 1. The valve plate 2 is rotatably arranged in the valve body 1 and is used to adjust the opening degree of the passage 11. The valve stem 3 is rotatably inserted into the valve body 1 and is fixedly connected to the valve plate 2. The stepping motor 4 is fixed outside the valve body 1 and is connected to the valve stem 3 through a coupling 5. The encoder 6 includes a grating part 61 fixedly sleeved on the valve stem 3, and a sensing part 62 fixed relative to the valve body 1 and used to sense the grating part 61. Wherein, when the stepping motor 4 drives the valve plate 2 to rotate in the valve body 1 through the valve stem 3, the sensing part 62 of the encoder 6 can sense the movement of the grating part 61 relative to the sensing part 62, and obtain the movement parameters of the valve plate 2 based on the sensing result.

[0042] The vacuum swing valve provided in this embodiment directly transmits the strong driving force of the stepper motor 4 to the valve plate 2 through the precise cooperation of the coupling 5 and the valve stem 3, drives the valve plate 2 to rotate flexibly in the valve body 1, and then accurately adjusts the opening of the channel 11. Among them, the vacuum swing valve abandons the traditional indirect tooth meshing transmission mode (that is, the motor power is first transmitted to the fan teeth, and then the fan teeth drive the valve plate 2 to rotate), and instead adopts a direct transmission mode (the valve stem 3 is directly connected to the stepper motor 4 through the coupling 5), eliminating the problem of control dead zone due to the meshing of the motor and the fan teeth (due to mechanical wear, the stepper motor 4 rotates when the teeth are meshed with the fan teeth, but the fan teeth cannot be driven to rotate by the teeth), significantly improving the accuracy of the vacuum swing valve, and thus enhancing the stability of the vacuum degree of the vacuum system. In addition, the grating part 61 of the encoder 6 is cleverly fixed on the valve stem 3. This design cleverly avoids the cumulative error that is easy to produce in traditional mechanical transmission, so that the sensing part 62 of the encoder 6 can sense the rotation dynamics of the valve stem 3 in the valve body 1 in real time and directly, thereby more accurately reflecting the opening state of the valve plate 2, and solving the problem of control dead zone that may exist between the encoder 6 and the valve stem 3. Furthermore, the accuracy of each step of the stepper motor 4 is due to the precise control of the electronic device, and there is no error accumulation, which brings higher positioning accuracy to the drive of the vacuum swing valve, ensures the ultimate precision of position control, and perfectly meets the high requirements for vacuum swing valves in a vacuum environment. The tacit cooperation of the stepper motor 4, the coupling 5 and the encoder 6 together create the vacuum swing valve's ability to accurately adjust the opening of the channel 11 in the vacuum system, fully meeting the stringent requirements of high-precision fluid control.

[0043] Preferably, the resolution of the encoder 6 is greater than or equal to 85000 CPR (Counts Per Revolution) to finely divide a complete movement cycle of the valve stem 3 into more subdivisions, so that the encoder 6 can keenly capture smaller angle changes, thereby achieving precise control of the rotation angle and speed.

[0044] Figure 3 FIG. 2 shows an exploded schematic diagram of the coupling 5 provided in this embodiment. Figure 3 Combined with Figure 1 and Figure 2As shown in the figure, the coupling 5 can be selected as a rigid coupling or a flexible coupling. Among them, the flexible coupling includes a first connecting body 51 fixedly arranged on the output shaft 41 of the stepping motor 4, a second connecting body 52 fixedly arranged on the valve stem 3 and mutually embedded with the first connecting body 51, and an elastic buffer 53 arranged at the joint between the first connecting body 51 and the second connecting body 52. The coupling 5 is connected to the output shaft 41 of the stepping motor 4 and the valve stem 3 in sequence through the first connecting body 51 and the second connecting body 52, and the elastic connecting piece arranged between the first connecting body 51 and the second connecting body 52 absorbs the connection deviation during the rotational fit of the first connecting body 51 and the second connecting body 52 when the stepping motor 4 drives the valve stem 3 to rotate, so that the first connecting body 51 and the second connecting body 52 can maintain smooth transmission even under deviation conditions. In addition, the elastic connecting piece can also provide buffering and shock absorption for the transmission of the two, so as to reduce the damage to the first connecting body 51 and the second connecting body 52 caused by the impact, thereby playing a role in protecting the first connecting body 51 and the second connecting body 52.

[0045] Preferably, the first connecting body 51 and the second connecting body 52 are made of steel or titanium alloy materials, ensuring the strength and durability of the coupling 5, so that the coupling 5 can withstand high torque and vibration. The elastic buffer 53 is made of rubber or latex materials to utilize the good elasticity and buffering effects of rubber or latex materials, so as to effectively absorb and reduce the impact and vibration between the first connecting body 51 and the second connecting body 52 and achieve the absorption of the connection deviation during their rotational fit, thereby ensuring smooth transmission between the stepping motor 4 and the valve stem 3.

[0046] Furthermore, the vacuum swing valve further includes a fixing seat 7 for fixedly connecting the stepping motor 4 and the valve body 1. It is ensured that the fixing seat 7 of the vacuum swing valve has an inner cavity 71 for accommodating the valve stem 3, the coupling 5, the encoder 6 and the output shaft 41 of the stepping motor 4. Through the setting of the inner cavity 71, the valve stem 3, the coupling 5, the encoder 6 and the output shaft 41 of the stepping motor 4 can be integrated in the fixing seat 7, reducing the space occupied by the vacuum swing valve and improving the integration degree of the vacuum swing valve.

[0047] Specifically, the inner cavity 71 includes a first chamber 712 and a second chamber 713. Among them, the valve stem 3, the coupling 5, the grating part 61 of the encoder 6 and the output shaft 41 of the stepping motor 4 are all arranged in the first chamber 712, the sensing part 62 of the encoder 6 is arranged in the second chamber 713, and the second chamber 713 penetrates the fixing seat 7 and is connected to the first chamber 712. The cavity separation design of the first chamber 712 and the second chamber 713 can ensure that the sensing part 62 of the encoder 6 can accurately identify the grating part 61 of the encoder 6 while avoiding unnecessary interference of the sensing part 62 on the moving grating part 61, and the sensing part 62 can better adapt to the grating part 61 installed on the valve stem 3.

[0048] Furthermore, the inner cavity 71 has a positioning step 711, and the valve stem 3 has a positioning shoulder 31 that abuts against the positioning step 711, so that the positioning step 711 can prevent the valve stem 3 from exiting the valve body 1 through the positioning shoulder 31 that abuts against it, enabling the valve stem 3 to be accurately positioned within the valve body 1 during installation, avoiding axial movement of the valve stem 3, and thus ensuring the stability and reliability of the valve stem 3. At the same time, the positioning step 711 can prevent the valve stem 3 from exiting the valve body 1 through the positioning shoulder 31 that abuts against it, ensuring the safety and stability of the valve stem 3 during operation.

[0049] Preferably, the valve stem 3 and the valve plate 2 are fixed by fastening bolts, which can not only ensure stable connection between the valve stem 3 and the valve plate 2 but also allow for disassembly, facilitating maintenance and repair.

[0050] Figure 4 shows a schematic structural diagram of the valve plate 2 and the valve stem 3 provided in this embodiment. As Figure 4 and in combination with Figure 1 and Figure 2 shown, a positioning groove 21 is provided on one of the valve stem 3 and the valve plate 2, and a positioning pin 32 that cooperates with the positioning groove 21 is provided on the other of them. The positioning groove 21 and the positioning pin 32 can enable the valve stem 3 and the valve plate 2 to be accurately positioned during installation, avoiding relative movement between the valve stem 3 and the valve plate 2, and thus ensuring the stability and reliability of the valve stem 3 and the valve plate 2 during operation. At the same time, the positioning pin 32 can be firmly installed in the positioning groove 21, ensuring the safety and stability of the valve stem 3 and the valve plate 2 during operation. In addition, this design also makes the installation and disassembly of the valve stem 3 and the valve plate 2 more convenient.

[0051] In this embodiment, the positioning groove 21 is provided on the valve plate 2, and the positioning pin 32 is provided on the valve stem 3. In other embodiments, the positioning groove can also be provided on the valve stem 3, and the positioning pin can also be provided on the valve plate 2. This embodiment does not make specific limitations in this regard, and any setting method that can achieve the above positioning effect is within the protection scope of the embodiments of the present disclosure.

[0052] This embodiment also provides a vacuum pressure control system, which includes a vacuum swing valve.

[0053] The vacuum pressure control system provided in this embodiment eliminates the control dead zone between the stepper motor 4 and the sector gear through a direct drive method, improving the accuracy and stability of the transmission. This helps the vacuum pressure control system reduce fluctuations when maintaining the vacuum degree and improve the overall stability of the vacuum pressure control system. The vacuum swing valve utilizes the high-precision angle control of the stepper motor 4 and the direct induction of the encoder 6 on the rotational movement of the valve stem 3 to achieve precise adjustment of the opening degree of the channel 11, enabling the vacuum pressure control system to more accurately control the vacuum degree and meet the requirements of high-precision fluid control.

[0054] Furthermore, the vacuum pressure control system further includes a control unit that is electrically connected to the stepper motor 4 and the encoder 6 of the vacuum swing valve and controls the stepper motor 4 based on motion parameters through the PID algorithm. The control unit uses the PID algorithm to perform real-time analysis on the motion parameters of the encoder 6. This control strategy significantly improves the response speed and stability of the vacuum pressure system, reduces system oscillation, and optimizes energy consumption. By precisely adjusting the rotation speed and position of the stepper motor 4, the system can respond more quickly to pressure changes, ensuring the stability and reliability of the process.

[0055] Furthermore, the PID algorithm includes the following formula:

[0056] e = R(t) - r(t)

[0057]

[0058] where u is the pulse signal used to control the stepper motor 4; e is the deviation signal, defined as the difference between the expected angle r(t) of the valve plate 2 in the valve body 1 given by the control unit and the output signal R(t) of the encoder 6. K P is the proportionality coefficient, used to adjust the intensity of the control response. T I is the integral time constant, used to reduce the steady-state error. T D is the derivative time constant, used to improve the system's response speed to deviation changes. u 0 is the control constant, used to compensate for the fixed deviation in the system. t is time. R(t) is the output signal of the encoder 6, including the actual angle of the valve plate 2 in the valve body 1. r(t) is the expected angle of the valve plate 2 in the valve body 1 given by the control unit.

[0059] By calculating and adjusting the pulse signal u in real time, the PID algorithm can dynamically adjust the rotation speed and position of the stepper motor 4 according to the deviation between the actual angle R(t) and the expected angle r(t) of the valve plate 2 in the valve body 1, thereby achieving precise control of the vacuum pressure. This control strategy not only improves the response speed and stability of the system but also effectively reduces energy consumption and optimizes the overall operation process.

[0060] In the above description of the present application, unless otherwise clearly defined and limited, terms such as "fixed", "installed", "connected" or "coupled" should be understood in a broad sense. For example, with respect to the term "connected", it can be a fixed connection, a detachable connection, or integrated; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, or it can be the communication inside two elements or the interaction relationship between two elements. Therefore, unless otherwise clearly defined in the present application, those skilled in the art can understand the specific meaning of the above terms in the present invention according to specific circumstances.

[0061] Based on the above description of the present application, those skilled in the art can also understand the following terms used, such as terms indicating orientation or positional relationship, such as "upper", "axial", etc., are based on the orientation or positional relationship shown in the drawings of the present application. They are only for the purpose of facilitating the description of the solution of the present invention and simplifying the description, rather than explicitly or implicitly indicating that the device or element involved must have the specific orientation, be constructed and operated in the specific orientation. Therefore, the above terms of orientation or positional relationship cannot be understood or interpreted as a limitation to the solution of the present invention.

[0062] In addition, the terms "first" or "second" etc. used in the present application to refer to numbers or ordinals are only for descriptive purposes and cannot be understood as explicitly or implicitly indicating relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" or "second" can explicitly or implicitly include at least one such feature. In the description of the present application, the meaning of "a plurality" is at least two, such as two, three or more, etc., unless otherwise clearly and specifically defined.

[0063] Although several embodiments of the present invention have been shown and described herein, it will be apparent to those skilled in the art that such embodiments are provided by way of example only. Many variations, changes and alternative ways may occur to those skilled in the art without departing from the spirit and scope of the present invention. It should be understood that various alternative embodiments of the embodiments of the present invention described herein may be employed in the practice of the present invention. The appended claims are intended to define the scope of protection of the present invention and thus cover equivalents or alternatives within the scope of these claims.

Claims

1. A vacuum swing valve, characterized in that: include: a valve body having a passage for fluid to pass therethrough; a valve plate rotatably disposed in the valve body and used to adjust the opening of the channel; A valve stem, which is rotatably inserted into the valve body and fixedly connected to the valve plate; A stepper motor is fixed outside the valve body and connected to the valve stem through a coupling; and An encoder, comprising a grating portion fixedly sleeved on the valve stem, and a sensing portion fixed relative to the valve body and used to sense the grating portion; When the stepper motor drives the valve plate to rotate in the valve body through the valve stem, the sensing portion of the encoder can sense the movement of the grating portion relative to it, and obtain the movement parameters of the valve plate based on the sensing result.

2. The vacuum swing valve according to claim 1, characterized in that: The coupling is a rigid coupling or a flexible coupling, wherein the flexible coupling includes a first connector fixedly mounted on the output shaft of the stepper motor, a second connector fixedly mounted on the valve stem and interlocked with the first connector, and an elastic buffer member disposed at the joint between the first connector and the second connector.

3. The vacuum swing valve according to claim 2, characterized in that: The first connector and the second connector are made of steel or titanium alloy, and the elastic buffer is made of rubber or latex.

4. The vacuum swing valve according to claim 1, characterized in that: The vacuum swing valve also includes a fixing seat for fixing the stepper motor to the valve body, and the fixing seat has an inner cavity for accommodating the valve stem, the coupling, the encoder and the output shaft of the stepper motor.

5. The vacuum swing valve according to claim 4, characterized in that: The inner cavity has a positioning step, and the valve stem has a positioning shoulder abutting against the positioning step, so that the positioning step can prevent the valve stem from withdrawing from the valve body through the positioning shoulder abutting against it.

6. The vacuum swing valve according to claim 5, characterized in that: The valve stem and the valve plate are fixed by fastening bolts.

7. The vacuum swing valve according to claim 6, characterized in that: One of the valve stem and the valve plate is provided with a positioning groove, and the other of the valve stem and the valve plate is provided with a positioning pin matched with the positioning groove.

8. A vacuum pressure control system, characterized in that: Comprising a vacuum swing valve as claimed in any one of claims 1 to 7.

9. The vacuum pressure control system according to claim 8, characterized in that: The vacuum pressure control system further includes a control unit that is electrically connected to the stepper motor and the encoder of the vacuum swing valve and controls the stepper motor based on the motion parameters through a PID algorithm.

10. The vacuum pressure control system according to claim 9, characterized in that: The PID algorithm includes the following formula: e=R(t)-r(t) Wherein, u is a pulse signal for controlling the stepper motor; e is a deviation signal; K P is the proportionality coefficient; T I is the integral time constant; T D is the differential time constant; u0 is the control constant; t is the time; R(t) is the output signal of the encoder, including the actual angle of the valve plate in the valve body; r(t) is the expected angle of the valve plate in the valve body given by the control unit.

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