A pneumatic three-position multi-way valve

Abstract

The present invention relates to a pneumatic three-position multi-way valve, which comprises a valve assembly and a pneumatic actuator. The valve assembly includes a valve body assembly and a valve core assembly. The valve body assembly includes a valve body and a box body arranged around the valve body. Pipe heads are provided on the side box body, the bottom box body and the top box body for the inlet and outlet of the medium. The valve core assembly includes a long valve core body and a short valve core body. The long valve core body and the short valve core body rotate synchronously, and a number of openings are provided on their respective surfaces for adapting to the pipe heads. Communication holes are correspondingly arranged on the valve body. When the pneumatic actuator is used to drive the valve core assembly to rotate, when the valve core assembly rotates, the cooperation among the pipe heads, the openings and the communication holes realizes the inlet and outlet of the medium through different paths. The present invention realizes the inlet and outlet of the medium through multiple paths, which can effectively ensure the use of multiple pipelines. Through pressure compensation and auxiliary sealing, the service life of the pneumatic three-position multi-way valve is greatly increased; secondly, the intermediate position hovering function is realized through the cooperation of different pistons and the cylinder block.

Description

Technical Field

[0001] The present invention relates to the technical field of fluid equipment, and in particular to a pneumatic three-position multi-way valve. Background Art

[0002] A pneumatic three-position multi-way valve, also known as a switching valve or a multi-position valve, is a commonly used control element that can achieve switching control between multiple channels in a valve body. The pneumatic three-position multi-way valve is usually used to control the flow rate, pressure, and direction in a hydraulic system, and is widely used in various fields such as machinery, aviation, aerospace, construction machinery, and rail transit. The working principle of the pneumatic three-position multi-way valve is to rotate the valve core so that different flow channels are connected to each other to achieve switching control of different fluid media. The pneumatic three-position multi-way valve usually consists of a valve body, a valve core, a spring, a sealing ring, a handle, an actuator, etc. The internal shape of the valve body is designed according to different functional requirements, and usually includes an inlet and outlet, a central flow channel, and multiple flow channel connection holes. The valve core is usually cylindrical, with multiple channels opened inside, and different channels can be connected to each other during rotational movement.

[0003] However, the existing pneumatic three-position multi-way valves have problems such as complex structures and low service lives. Summary of the Invention

[0004] The purpose of the present invention is to provide a pneumatic three-position multi-way valve to solve the above technical problems.

[0005] To achieve the above purpose, the present invention provides the following technical solutions:

[0006] A pneumatic three-position multi-way valve, characterized in that it includes a valve assembly and a pneumatic actuator. The valve assembly includes a valve body assembly and a valve core assembly arranged inside the valve body assembly. The valve body assembly includes a valve body and a box body arranged around the valve body. The box body includes a side box body, a bottom box body, and a top box body. Pipe heads for the inlet and outlet of the medium are arranged on the side box body, the bottom box body, and the top box body. The valve core assembly includes a long valve core body and a short valve core body. The long valve core body and the short valve core body rotate synchronously, and a plurality of openings are arranged on their respective surfaces for adapting to the pipe heads. Communication holes are correspondingly arranged on the valve body. The pneumatic actuator is used to drive the rotation of the valve core assembly. When the valve core assembly rotates, the cooperation between the pipe heads, the openings, and the communication holes realizes the inlet and outlet of the medium through different paths.

[0007] The present invention is further provided that the pneumatic actuator includes a cylinder body and end covers arranged at both ends of the cylinder body, the end covers include a first end cover and a second end cover, the first end cover is provided with a first air inlet hole, the second end cover is provided with a second air inlet hole, the cylinder body is provided with a third air inlet hole, the first end cover is provided with a first piston on the inner side of the first end cover, the second end cover is provided with a second piston on the inner side of the second end cover, wherein the first piston is connected to the third piston, a rack is provided between the second piston and the third piston, the rack is matched with a gear, the gear is provided on a corresponding gear shaft, the first piston and the third piston are fixedly connected, the gear shaft is connected to the valve core assembly and drives the valve core assembly to rotate, the first air inlet hole is used to drive the first piston to move when air is inletted, the second air inlet hole is used to drive the second piston to move when air is inletted, and the third air inlet hole is used to drive the third piston to move when air is inletted, and the second piston is provided with a push rod to limit the position of the third piston, wherein the first piston, the second piston and the third piston are used in combination to realize the change of the rotation angle of the gear shaft, that is, by changing the cylinder body, the cylinder body part where the second piston is provided and the length of the push rod, the change of the total stroke angle and the intermediate hovering angle is realized.

[0008] The present invention further provides that the valve assembly and the pneumatic actuator are connected via a flange, a linkage shaft connected to the gear shaft is provided in the flange, a bearing cover and a compensating sealing assembly are provided on the linkage shaft, thereby realizing the combination of the positioning function and the compensating sealing function of the cover.

[0009] The present invention is further arranged that the openings arranged on the long valve core body include a first type of openings and a second type of openings, the second type of openings include air-blocking openings provided with air-blocking plugs and air-venting openings provided with air-venting plugs, a yielding step is formed at the air-blocking openings, the air-blocking plug on the long valve core body is provided with a medium port for medium to pass through, the medium flows from the medium port to the yielding step, the medium acts on the air-blocking plug to cause it to deviate to one side of the valve body to achieve pressure sealing compensation.

[0010] The present invention is further arranged that a second type of openings is provided on the short valve core body, the second type of openings include air-blocking openings provided with air-blocking plugs and air-venting openings provided with air-venting plugs, a yielding step is provided at the air-blocking openings, an inlet port communicating with the yielding step is provided on the short valve core body, when the medium enters the yielding step from the inlet port, the medium acts on the air-blocking plug in the short valve core body to cause it to deviate to one side of the valve body to achieve pressure sealing compensation.

[0011] The present invention is further arranged that the two ends of the linkage shaft respectively form a first connection part connected to the gear shaft and a second connection part connected to the long valve core body, the first connection part and the second connection part are square shaft structures, wherein the first connection part and the second connection part are provided with fool-proof holes, and fool-proof fasteners are arranged in the fool-proof holes.

[0012] The present invention is further configured such that a concentric positioning step is provided between the actuator assembly and the valve assembly to ensure concentric transmission of the output shaft of the actuator and the valve stem.

[0013] The present invention is further configured such that a positioning bronze bushing is provided on the gear shaft. The positioning bronze bushing includes an upper positioning bronze bushing and a lower positioning bronze bushing, and a stepped portion is formed on the gear shaft at the lower end of the upper positioning bronze bushing.

[0014] The present invention is further configured such that snap ring openings are formed at both ends of the cylinder block, and snap ring grooves are formed on the first end cover and the second end cover. The snap ring grooves are used for placing snap rings connecting the cylinder block and the first end cover and the second end cover. A pin hole is formed in the snap ring groove, a limit pin is formed in the pin hole, and a limit groove cooperating with the limit pin is formed on the snap ring. When the snap ring is inserted from the snap ring opening, the first end cover or the second end cover is rotated, and the snap ring is deformed and inserted into the snap ring groove along the snap ring groove, and the limit groove cooperates with the limit pin to fix the snap ring.

[0015] The present invention is further configured such that an air vent plug of the same size is provided opposite to each air shut-off plug to achieve symmetric centering.

[0016] The beneficial effects of the present invention: In the present invention, by combining a pneumatic actuator and a valve assembly, through the valve body of the valve assembly and the box body arranged around the valve body, the box body includes a side box body, a bottom box body and a top box body, and pipe heads for medium inlet and outlet are provided on the side box body, the bottom box body and the top box body. The valve core assembly includes a long valve core body and a short valve core body. The long valve core body and the short valve core body rotate synchronously, and a plurality of openings are provided on their respective surfaces to adapt to the pipe heads. A communication hole is correspondingly provided on the valve body. When the pneumatic actuator is used to drive the valve core assembly to rotate, when the valve core assembly rotates, the cooperation between the pipe head, the opening and the communication hole realizes the inlet and outlet of the medium in different paths, and the realization of the multi-path inlet and outlet of the medium can effectively ensure the use of a variety of pipelines, thereby reducing the use demand of a single pipeline. Through pressure compensation and auxiliary sealing, the service life of the pneumatic three-position multi-way valve is greatly increased; and the switching of pipelines is realized by the pneumatic actuator, and the angle range can be accurately adjusted. Secondly, the intermediate position hovering function is realized by pistons of different sizes. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The drawings described herein are used to provide a further understanding of the present application, and constitute a part of the present application. The schematic embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation to the present application. In the drawings:

[0018] Figure 1 is an exploded structural schematic diagram of an embodiment of the present invention.

[0019] Figure 2 is an assembled schematic diagram of an embodiment of the present invention.

[0020] Figure 3 This is a schematic structural view of the valve assembly according to an embodiment of the present invention.

[0021] Figure 4 This is a schematic structural view of the pneumatic actuator according to an embodiment of the present invention.

[0022] Figure 5 This is a schematic structural view of the flange according to an embodiment of the present invention.

[0023] Figure 6 This is a cross-sectional view of the flange according to an embodiment of the present invention.

[0024] Figure 7 This is a schematic structural view of the long valve core body according to an embodiment of the present invention.

[0025] Figure 8 This is a cross-sectional view of the long valve core body according to an embodiment of the present invention.

[0026] Figure 9 This is a schematic structural view of the short valve core body according to an embodiment of the present invention.

[0027] Figure 10 This is a cross-sectional view of the short valve core body according to an embodiment of the present invention.

[0028] Figure 11 This is a schematic structural view of the end cover and the snap ring according to an embodiment of the present invention.

[0029] Figure 12 This is a cross-sectional view of the valve assembly according to an embodiment of the present invention.

[0030] Figure 13 is Figure 12 an enlarged view of part A in

[0031] Reference numerals:

[0032] 10. Valve assembly; 101. Valve body assembly; 1011. Valve body; 10111. Communication hole; 1012. Side box; 1013. Top box; 1014. Bottom box; 1015. Pipe head; 102. Spool assembly; 1021. Long spool body; 1022. Short spool body; 1023. Second type of opening; 10231. Air-blocking opening; 10232. Air-venting opening; 1024. Air-blocking plug; 1025. Air-venting plug; 1026. First type of opening; 20. Pneumatic actuator; 201. Cylinder block; 202. First end cover; 203. Second end cover; 204. First piston; 205. Second piston; 206. Third piston; 207. Push rod; 208. Rack; 209. Gear; 2010. Gear shaft; 2011. Cylinder part of the second piston; 30. Flange; 301. Outer housing; 302. Linkage shaft; 3021. First connection part; 3022. Second connection part; 303. Pressure-bearing cover; 304. Compensation spring; 305. Packing support ring; 306. Packing seal ring; 307. Packing compression ring; 40. First air inlet hole; 50. Second air inlet hole; 60. Third air inlet hole; 70. Relief step; 80. Medium port; 90. Inlet port; 100. Anti-fooling hole; 110. Anti-fooling fastener; 120. Shaft groove; 130. Connecting shaft; 140. Upper positioning copper bushing; 150. Lower positioning copper bushing; 160. Circlip groove; 170. Circlip; 180. Circlip slot; 190. Pin hole; 200. Limit pin; 210. Limit groove; 220. Step part; Detailed implementation manners

[0033] The following will describe in detail the implementation manners of the present application in conjunction with the drawings and embodiments, so as to fully understand how the present application uses technical means to solve technical problems and achieve the implementation process of technical effects and implement accordingly.

[0034] As Figures 1 - 13As shown in the figure, the present invention provides a pneumatic three-position multi-way valve, which includes a valve assembly 10 and a pneumatic actuator 20. The valve assembly 10 includes a valve body assembly 101 and a spool assembly 102 disposed within the valve body assembly 101. The valve body assembly 101 includes a valve body 1011 and a box body disposed around the valve body 1011. The box body includes a side box body 1012, a bottom box body 1014, and a top box body 1013. Pipe heads 1015 are provided on the side box body 1012, the bottom box body 1014, and the top box body 1013 for the inlet and outlet of the medium. The spool assembly 102 includes a long spool body 1021 and a short spool body 1022. The long spool body 1021 and the short spool body 1022 rotate synchronously, and a plurality of openings are provided on their respective surfaces for adapting to the pipe heads 1015. A communication hole 10111 is correspondingly provided on the valve body 1011. The pneumatic actuator 20 is used to drive the spool assembly 102 to rotate. When the spool assembly 102 rotates, the cooperation between the pipe heads 1015, the openings, and the communication hole 10111 realizes the inlet and outlet of the medium through different paths.

[0035] In this embodiment, the pneumatic actuator 20 includes a cylinder block 201 and end covers disposed at both ends of the cylinder block 201. The end covers include a first end cover 202 and a second end cover 203. A first air inlet hole 40 is provided on the first end cover 202, a second air inlet hole 50 is provided on the second end cover 203, and a third air inlet hole 60 is provided on the cylinder block 201. A first piston 204 is disposed inside the first end cover 202, and a second piston 205 is disposed inside the second end cover 203. A third piston 206 is connected to the first piston 204. A rack 208 is disposed between the second piston 205 and the third piston 206. The rack 208 is cooperatively provided with a gear 209. The gear 209 is disposed on a corresponding gear shaft 2010.

[0036] The cross-sectional areas of the second piston and the third piston are the same, and the cross-sectional area of the first piston is larger than the cross-sectional areas of the second piston and the third piston. The first piston 204 and the third piston 206 are fixedly connected. The gear shaft 2010 is connected to the spool assembly 102 and drives the spool assembly 102 to rotate. When the first air inlet hole 40 admits air, it is used to drive the first piston 204 to move. When the second air inlet hole 50 admits air, it drives the second piston 205 to move. When the third air inlet hole 60 admits air, it is used to drive the third piston 206 to move. The cooperation of the first piston 204, the second piston 205, and the third piston 206 realizes the change of the rotation angle of the gear shaft 2010, that is, by changing the cylinder block, the cylinder part 2011 provided with the second piston, and the length of the ejector rod 207, the total stroke angle and the intermediate hovering angle are changed. The ejector rod 207 is disposed on the second piston and faces the third piston. Its specific performance is as follows:

[0037] When the first air inlet hole 40 admits air, the second air inlet hole 50 and the third air inlet hole 60 do not admit air, and the first piston 204 moves in the direction of the third piston 206, thereby causing the gear shaft 2010 to rotate by a first angle, and the maximum of the first angle is 180°; when the third air inlet hole 60 admits air, the first air inlet hole 40 and the second air inlet hole 50 do not admit air, then the gear shaft 2010 rotates by a second angle, and the maximum of the second angle is 180°; when the first air inlet hole 40, the second air inlet hole 50 and the third air inlet hole 60 admit air simultaneously, the second piston 205 moves towards the third piston 206, and a limiting rod is provided on the third piston 206 to limit the movement range of the third piston 206, and the size of the movement range is related to the length of the limiting rod. Therefore, simultaneous air intake in cooperation with the length of the limiting rod can fix the gear shaft 2010 at a certain rotation angle within the range of 0 - 180°. According to the air intake states of different air inlet holes, the intermediate position hovering function of the pneumatic actuator 20 is realized. This intermediate position does not simply refer to the 90° position, but should be understood as any position within the range of 0 - 180°.

[0038] In addition, during the rotation of the linkage shaft 302, wear of the shaft will occur, resulting in a decrease in the sealing effect of the linkage shaft 302 and a decrease in concentricity. Therefore, the following method is adopted:

[0039] A linkage shaft connected to the gear shaft is arranged inside the flange.

[0040] Based on the above situation, in this embodiment, the valve assembly 10 and the pneumatic actuator 20 are connected through a flange 30. The flange 30 includes an outer housing 301 and a linkage shaft 302 connected to the gear shaft 2010. A bearing gland and a compensation sealing assembly are arranged on the linkage shaft to combine the positioning function and the compensation sealing function of the gland; specifically, the linkage shaft 302 is sequentially provided with a pressure bearing cover 303, a compensation spring 304, a packing support ring 305, a packing sealing ring 306, and a packing gland 307 from one side of the gear shaft 2010 to one side of the valve assembly 10. The compensation spring 304, the packing support ring 305, the packing sealing ring 306, and the packing gland 307 constitute the compensation sealing assembly; wherein a plurality of the packing sealing rings 306 are provided and are of a V-shaped structure. The pressure bearing cover 303, the compensation spring 304, the packing support ring 305, the packing sealing ring 306, and the packing gland 307 are used in combination to achieve the compensation sealing during the rotation of the linkage shaft 302 and to ensure that the linkage shaft 302 does not become eccentric during rotation. The compensation spring 304 is a wave spring, but other types of springs can also be used.

[0041] In this embodiment, the openings provided on the long valve core body 1021 include a first type of opening 1026 and a second type of opening 1023. The second type of opening 1023 includes an airtight opening 10231 provided with an airtight plug 1024 and a ventilation opening 10232 provided with a ventilation plug 1025. A relief step 70 is formed at the airtight opening 10231. A medium port 80 for the medium to pass through is provided on the airtight plug 1024 on the long valve core body 1021. The medium flows from the medium port 80 into the relief step 70, and the medium acts on the airtight plug 1024 to cause it to shift towards the valve body 1011 side to achieve pressure seal compensation.

[0042] Similarly, the second type of opening 1023 is provided on the short valve core body 1022. The second type of opening 1023 includes an airtight opening 10231 provided with an airtight plug 1024 and a ventilation opening 10232 provided with a ventilation plug 1025. A relief step 70 is provided at the airtight opening 10231. An inlet 90 communicating with the relief step 70 is opened on the short valve core body 1022. When the medium enters the relief step 70 from the inlet 90, the medium acts on the airtight plug 1024 in the short valve core body 1022 to cause it to shift towards the valve body 1011 side to achieve pressure seal compensation. It is worth mentioning that a ventilation plug 1025 of the same size is provided opposite to each airtight plug 1024 to achieve symmetric centering, so that the loads of the long valve core body 1021 and the short valve core body 1022 are in a balanced state.

[0043] In addition, when the linkage shaft 302, the gear shaft 2010, and the long valve core body 1021 are installed, in the prior art, a round shaft is generally used to connect the three. However, when using a round shaft structure, the assembly accuracy requirements are too high, and misassembly often occurs during assembly. Based on the above situation, the following technical solution is provided in this embodiment:

[0044] Both ends of the linkage shaft 302 respectively form a first connection portion 3021 connected to the gear shaft 2010 and a second connection portion 3022 connected to the long valve core body 1021. The first connection portion 3021 and the second connection portion 3022 are in a square shaft structure. Anti-fooling holes 100 are opened on the first connection portion 3021 and the second connection portion 3022. Anti-fooling fasteners 110 are provided in the anti-fooling holes 100. By using a square shaft structure and providing anti-fooling holes 100 in cooperation with anti-fooling fasteners 110, the situation of misassembly can be avoided. In this embodiment, the anti-fooling fastener 110 is a bolt.

[0045] In addition, misinstallation may also occur during the installation of the long valve core body 1021 and the short valve core body 1022. Therefore, the following solution is adopted: a shaft groove 120 is formed on one side of the long valve core body 1021 facing the short valve core body 1022, and a connecting shaft 130 is formed on one side of the short valve core body 1022 facing the long valve core body 1021. The connecting shaft 130 has a square shaft structure, and an anti-fooling hole 100 is provided thereon. An anti-fooling fastener 110 is arranged in the anti-fooling hole 100. Similarly, the use of a square shaft structure and the arrangement of the anti-fooling hole 100 in cooperation with the anti-fooling fastener 110 can avoid misinstallation. In this embodiment, the anti-fooling fastener 110 is a bolt.

[0046] In addition, a concentric positioning step is provided between the actuator assembly and the valve assembly to ensure the concentric transmission of the actuator gear shaft and the linkage shaft. Therefore, a positioning copper sleeve is provided on the gear shaft 2010. The positioning copper sleeve includes an upper positioning copper sleeve 140 and a lower positioning copper sleeve 150. A step portion 220 is formed on the gear shaft 2010 at the lower end of the upper positioning copper sleeve. The cooperation of the upper and lower positioning copper sleeves 150 and the step portion 220 can ensure that the gear shaft 2010 has a good centering effect.

[0047] In addition, when the end cover of the pneumatic actuator 20 is connected to the cylinder block 201, the existing technical means are all connected by bolts. However, the anti-vibration performance of bolt connection is relatively poor: the connection strength and stability of bolt connection are limited to a certain extent, and it may be prone to loosening in applications with large vibrations, affecting the operation stability and service life of the equipment.

[0048] Based on the above situation, in this embodiment, a snap ring 170 is used to connect the end cover and the cover body. The specific means are as follows:

[0049] In this embodiment, snap ring openings 160 are formed at both ends of the cylinder block 201, and snap ring grooves 180 are formed on the first end cover 202 and the second end cover 203. The snap ring grooves 180 are used to place the snap ring 170 connecting the cylinder block 201 and the first end cover 202 and the second end cover 203. A pin hole 190 is formed in the snap ring groove 180, and a limit pin 200 is formed in the pin hole 190. A limit groove 210 is formed on the snap ring 170 to cooperate with the limit pin 200. When the snap ring 170 is inserted from the snap ring opening 160, the first end cover 202 or the second end cover 203 is rotated, and the snap ring 170 is deformed and inserted into the snap ring groove 180 along the snap ring groove 180, and the limit groove 210 cooperates with the limit pin 200 to fix the snap ring 170.

[0050] In the present invention, by combining a pneumatic actuator 20 and a valve assembly 10, a valve body 1011 of the valve assembly 10 and a box body arranged around the valve body 1011 are provided. The box body includes a side box body 1012, a bottom box body 1014 and a top box body 1013. Pipe heads 1015 are arranged on the side box body 1012, the bottom box body 1014 and the top box body 1013 for the inlet and outlet of the medium. A valve core assembly 102 includes a long valve core body 1021 and a short valve core body 1022. The long valve core body 1021 and the short valve core body 1022 rotate synchronously, and a plurality of openings are arranged on their respective surfaces for adapting to the pipe heads 1015. A communication hole 10111 is correspondingly arranged on the valve body 1011. When the pneumatic actuator 20 is used to drive the valve core assembly 102 to rotate, when the valve core assembly 102 rotates, the cooperation between the pipe heads 1015, the openings and the communication hole 10111 realizes the inlet and outlet of the medium through different paths, and the multi-path inlet and outlet of the medium effectively ensures the use of multiple pipelines, thereby reducing the use demand of a single pipeline. Through pressure compensation and auxiliary sealing, the service life of the pneumatic three-position multi-way valve is greatly increased; moreover, the switching of pipelines is realized by the pneumatic actuator 20, and the angle range can be accurately adjusted. Secondly, the intermediate position hovering function is realized by pistons of different sizes.

Claims

1. A pneumatic three-position multi-way valve, characterized in that, The invention comprises a valve assembly and a pneumatic actuator, wherein the valve assembly comprises a valve body assembly and a valve core assembly arranged in the valve body assembly, wherein the valve body assembly comprises a valve body and a box body arranged around the valve body, wherein the box body comprises a side box body, a bottom box body and a top box body, wherein the side box body, the bottom box body and the top box body are provided with pipe heads for medium inlet and outlet, the valve core assembly comprises a long valve core body and a short valve core body, wherein the long valve core body and the short valve core body rotate synchronously, and a plurality of openings are provided on the surface of each of the long valve core body and the short valve core body for adapting the pipe heads, wherein the valve body is correspondingly provided with a connecting hole, and the pneumatic actuator is used to drive the valve core assembly to rotate, and when the valve core assembly rotates, the pipe heads, the openings The holes and the connecting holes cooperate to realize the entry and exit of media through different paths. The pneumatic actuator includes a cylinder body and end covers arranged at both ends of the cylinder body, the end covers include a first end cover and a second end cover, and a retaining spring opening is formed on both ends of the cylinder body, and a retaining spring groove is formed on the first end cover and the second end cover. The retaining spring groove is used to place a retaining spring connecting the cylinder body and the first end cover and the second end cover, wherein a pin hole is formed on the retaining spring groove, and a limit pin is formed in the pin hole, and a limit groove that cooperates with the limit pin is formed on the retaining spring. When the retaining spring is installed from the retaining spring opening, the first end cover or the second end cover is rotated, and the retaining spring is deformed along the retaining spring groove and installed into the retaining spring groove, and the limit groove cooperates with the limit pin to fix the retaining spring.

2. The pneumatic three-position multi-way valve according to claim 1, wherein The first end cover is provided with a first air inlet hole, the second end cover is provided with a second air inlet hole, the cylinder body is provided with a third air inlet hole, the first end cover is provided with a first piston on the inner side, the second end cover is provided with a second piston on the inner side, wherein the first piston is connected to the third piston, a rack is provided between the second piston and the third piston, the rack is provided with a gear in cooperation with the gear, the gear is provided on a corresponding gear shaft, the first piston and the third piston are fixedly connected, the gear shaft is connected to the valve core assembly and drives the valve core assembly to rotate, the first air inlet hole is used to drive the first piston to move when air is inletted, the second air inlet hole is used to drive the second piston to move when air is inletted, and the third air inlet hole is used to drive the third piston to move when air is inletted, and the second piston is provided with a push rod to limit the position of the third piston, wherein the first piston, the second piston and the third piston are used in combination to realize the change of the rotation angle of the gear shaft, that is, the change of the total stroke angle and the intermediate hovering angle is realized by changing the cylinder body, the cylinder body part where the second piston is provided and the length of the push rod.

3. A pneumatic three-position multi-way valve according to claim 1, characterized in that, The valve assembly is connected to the pneumatic actuator via a flange, a linkage shaft connected to the gear shaft is arranged in the flange, a bearing gland and a compensating seal assembly are arranged on the linkage shaft, so as to realize the combination of the positioning function and the compensating seal function of the gland.

4. The pneumatic three-position multi-way valve according to claim 1, characterized in that, The openings arranged on the long valve core body include a first type of openings and a second type of openings, the second type of openings include air-blocking openings provided with air-blocking plugs and air-venting openings provided with air-venting plugs, the air-blocking openings are formed with yielding steps, the air-blocking plug on the long valve core body is provided with a medium port for medium to pass through, the medium flows from the medium port to the yielding step, the medium acts on the air-blocking plug to cause it to deviate to one side of the valve body to achieve pressure sealing compensation.

5. A pneumatic three-position multi-way valve according to claim 1, characterized in that, The short valve core body is provided with a second type of openings, which include air-blocking openings provided with air-blocking plugs and air-venting openings provided with air-venting plugs. A yielding step is provided at the air-blocking openings. The short valve core body is provided with an inlet port connected to the yielding step. When the medium enters the yielding step from the inlet port, the medium acts on the air-blocking plug in the short valve core body to cause it to deviate to one side of the valve body to achieve pressure sealing compensation.

6. The pneumatic three-position multi-way valve according to claim 3, characterized in that, The two ends of the linkage shaft respectively form a first connection part connected to the gear shaft and a second connection part connected to the long valve core body, and the first connection part and the second connection part are square shaft structures, wherein the first connection part and the second connection part are provided with anti-fool holes, and anti-fool fasteners are arranged in the anti-fool holes.

7. A pneumatic three-position multi-way valve according to claim 1, characterized in that, A concentric positioning step is provided between the actuator assembly and the valve assembly to ensure concentric transmission of the actuator gear shaft and the linkage shaft.

8. A pneumatic three-position multi-way valve according to claim 7, characterized in that, A positioning copper sleeve is arranged on the gear shaft, and the positioning copper sleeve comprises an upper positioning copper sleeve and a lower positioning copper sleeve, and a step portion is formed on the gear shaft at the lower end of the upper positioning copper sleeve.

9. A pneumatic three-position multi-way valve according to claim 5 or 6, characterized in that Opposite each air-blocking plug, a venting plug of the same size is arranged to achieve symmetrical centering.

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