A pneumatic drive mechanism and a valve using the pneumatic drive mechanism

Abstract

The present invention relates to a pneumatic drive mechanism and a valve using the pneumatic drive mechanism. The pneumatic drive mechanism comprises a housing, a power output shaft is rotatably provided on the housing, and a pneumatic motor is provided on the housing. A first valve block and a second valve block are provided in the housing, and a housing air inlet and a housing air outlet are provided on the housing. The housing air inlet, the first valve block and the motor air inlet are connected by an air inlet pipe, and the housing air outlet, the second valve block and the motor air outlet are connected by an air outlet pipe. A valve channel is provided on each valve block, and a first push rod is provided on each valve block to elastically guide and move. A torque switch is also provided in the housing, and the torque switch comprises a torque shaft, and a top pressure structure is provided at the end of the torque shaft. The power output shaft and the torque shaft are connected by a second transmission structure. When the valve stem is stuck, the second transmission structure drives the torque shaft to rotate, and the top pressure structure will push the corresponding first push rod to block the valve channel on the corresponding valve block to cut off the air source, thereby avoiding the problem of bending or breaking of the valve stem due to continued force.

Description

Technical Field

[0001] The present invention relates to the field of valve actuators, and in particular to a pneumatic drive mechanism and a valve using the pneumatic drive mechanism. Background Art

[0002] During the use of valves, it is inevitable that the valve will be stuck and unable to close, especially for valves used in harsh working conditions and valves used for a long time. For valves using pneumatic drive mechanisms, when the valve is stuck and cannot be closed, the torque of the pneumatic drive mechanism will suddenly increase a lot, which can easily deform or break the valve stem, causing the valve to be unable to open and close, bringing safety hazards to production. Summary of the invention

[0003] The object of the present invention is to provide a pneumatic drive mechanism to solve the problem in the prior art that when the valve is stuck, the torque of the pneumatic drive mechanism suddenly increases, causing the valve stem to deform or break; at the same time, the object of the present invention is also to provide a valve using the above-mentioned pneumatic drive mechanism.

[0004] To achieve the above-mentioned purpose, a pneumatic drive mechanism of the present invention adopts the following technical scheme: a pneumatic drive mechanism includes a shell, a power output shaft is rotatably arranged on the shell, a pneumatic motor is arranged on the shell, a shell air inlet and a shell air outlet are arranged on the shell, the pneumatic motor has a motor air inlet and a motor air outlet, the shell air inlet is connected with the motor air inlet through an air inlet pipe, the shell air outlet is connected with the motor air outlet through an air outlet pipe, and the transmission shaft of the pneumatic motor is connected with the power output shaft through a first transmission structure; a first valve block is arranged on the air inlet pipe in the shell, a second valve block is arranged on the air outlet pipe in the shell, each valve block is provided with a valve channel connected with the corresponding air pipe, and each valve block is elastically and guided to move and is provided with a valve capable of opening and blocking the corresponding valve channel. The first push rod; a torque switch is also arranged in the shell, and the torque switch includes a torque shaft rotatably arranged on the shell, and the end of the torque shaft is provided with a pressing structure for pressing and cooperating with the first push rod on the corresponding valve block; the power output shaft and the torque shaft are connected by a second transmission structure, so that when the valve is stuck and cannot be opened or closed, the power output shaft can drive the torque shaft to rotate so that the corresponding first push rod closes the valve channel of the corresponding valve block; the pressing structure includes a mounting sleeve that can be synchronously rotated and arranged on the torque shaft, and a lug is arranged on the outer wall of the mounting sleeve, and the lug has an arc end, and a plurality of grooves are arranged on the lower side surface of the arc end at intervals along the circumferential direction, and an adjusting rod is movably installed on the lug, and a block that cooperates with the circumferential clamp of the groove is provided at the end of the adjusting rod, and the adjusting rod and the lug are connected. A first spring is arranged between the gears, and the top pressure structure also includes a top pressure plate rotatably arranged on the torque shaft, and the top pressure plate is provided with an adjusting long hole whose length points to the axis of the torque shaft, and a guide column inserted into the adjusting long hole to drive the top pressure plate to rotate is arranged on the corresponding end surface of the adjusting rod, and the axis of the guide column is eccentrically arranged with the axis of the adjusting rod; the first transmission structure includes an input gear arranged on the transmission shaft, and a shaft sleeve is rotatably arranged on the power output shaft, and the shaft sleeve has a concentric section at the upper end that is coaxial with the shaft sleeve and an eccentric section at the lower end, a main gear is synchronously rotated on the concentric section, and an auxiliary gear is synchronously installed on the eccentric section, and a transmission sheet is also synchronously rotated on the power output shaft, and a third transmission structure that drives the transmission sheet to rotate is arranged on the auxiliary gear; the second transmission structure includes The second transmission structure also includes a worm gear that is rotatably arranged on the housing, and the worm gear has an inner ring gear structure that meshes with the auxiliary gear for transmission. The inner ring gear structure and the auxiliary gear form a planetary gear transmission with a small tooth difference. The worm gear also has an outer ring gear structure. The second transmission structure also includes a worm gear that is rotatable and can be axially guided and moved in the housing for cooperating with the outer ring gear structure. The worm gear is elastically installed by a second spring to achieve horizontal elastic movement. An annular groove is arranged on the worm gear, and a shift fork that is engaged with the annular groove along the axial direction of the worm gear is arranged at the lower end of the torque shaft, so that the shift fork drives the torque shaft to rotate when the worm gear moves axially. A stroke limiting structure is arranged in the housing, and the stroke limiting structure includes a second push rod that is elastically and guides movement and is arranged on each valve block and can open and block the valve path.

[0005] A hand wheel is arranged at the end of the worm extending out of the housing.

[0006] The stroke limiting structure also includes a mounting frame, on which a pressing cam is rotatably provided for pressing and cooperating with the corresponding second push rod, each pressing cam is rotatably installed on the mounting frame through a camshaft, each camshaft is provided with a first gear, and a power shaft is also rotatably provided on the mounting frame, on which a second gear is provided, the first gear and the second gear are transmitted through a gear set, a third gear is provided at the lower end of the power shaft, and a fourth gear meshing with the third gear is provided on the power output shaft.

[0007] The valve channels on each of the valve blocks include a main valve channel, and the valve block is also provided with a secondary valve channel arranged parallel to the main valve channel, a first connecting valve channel and a second connecting valve channel are arranged between the main valve channel and the secondary valve channel, the first connecting valve channel and the second connecting valve channel are connected through the connecting valve channel, a movable valve core is arranged in the secondary valve channel to guide and move between the first connecting valve channel and the second connecting valve channel, a first mounting cavity is arranged on the first connecting valve channel for installation of a first push rod, and a second mounting cavity is arranged on the second connecting valve channel for installation of a second push rod, and an intermediate valve channel connecting the main valve channel and the secondary valve channel is also provided on the valve block, a blocking column is installed in the intermediate valve channel for guiding and moving up and down and movably sealing, the lower end of the blocking column has an annular cutting groove for gas on both sides of the main valve channel to pass through, the blocking column also has a stopping portion that blocks the main valve channel after moving, a first valve core connecting hole connecting the intermediate valve channel and the first connecting valve channel is arranged at one end of the valve core, and a second valve core connecting hole connecting the intermediate valve channel and the second connecting valve channel is arranged at the other end of the valve core.

[0008] Each installation cavity includes a guide installation section and a connecting section, each connecting section is sealed with a fixed block, each fixed block has a fixed block cavity and a central through hole, a main valve channel connecting cavity connected to the main valve channel is formed between the fixed block and the connecting section, a sealing plate that cooperates with the central through hole of the fixed block is elastically arranged in the main valve channel connecting cavity, each push rod includes a guide sealing part that guides and moves and is sealed in the installation section, a pushing part is arranged at the end of the guide sealing part, a fourth spring is arranged between the pushing part and the fixed block, the diameter of the pushing part is smaller than the diameter of the central through hole of the fixed block, and is used to push the sealing plate to allow gas to pass.

[0009] A valve using the above-mentioned pneumatic drive mechanism of the present invention adopts the following technical scheme: a valve includes a valve body, a valve seat and a valve plate are arranged in the valve body, the valve plate is connected to a valve stem, and also includes a pneumatic drive mechanism for driving the valve stem to rotate, the pneumatic drive mechanism includes a shell, a power output shaft is rotatably arranged on the shell, a pneumatic motor is arranged on the shell, a shell air inlet and a shell air outlet are arranged on the shell, the pneumatic motor has a motor air inlet and a motor air outlet, the shell air inlet is connected to the motor air inlet through an air inlet pipe, the shell air outlet is connected to the motor air outlet through an air outlet pipe, the transmission shaft of the pneumatic motor is connected to the power output shaft through a first transmission structure; a first valve block is arranged on the air inlet pipe in the shell, and a second valve block is arranged on the air outlet pipe in the shell, Each valve block is provided with a valve channel connected to the corresponding air pipe, and each valve block is elastically and guideably provided with a first push rod capable of opening and blocking the corresponding valve channel; a torque switch is also provided in the housing, and the torque switch includes a torque shaft rotatably provided on the housing, and the end of the torque shaft is provided with a pressing structure for pressing and cooperating with the first push rod on the corresponding valve block; the power output shaft and the torque shaft are connected by a second transmission structure, so that when the valve is stuck and cannot be opened or closed, the power output shaft can drive the torque shaft to rotate so that the corresponding first push rod closes the valve channel of the corresponding valve block; the pressing structure includes a mounting sleeve that can be synchronously rotatably provided on the torque shaft, and a lug is provided on the outer wall of the mounting sleeve, and the lug has an arc end, and the lower side surface of the arc end is spaced circumferentially A plurality of slots are provided, an adjusting rod is movably installed on the lug, a block which cooperates with the circumferential clamp of the slot is provided at the end of the adjusting rod, a first spring is provided between the adjusting rod and the lug, the top pressure structure also includes a top pressure plate rotatably arranged on the torque shaft, an adjusting long hole whose length points to the axis of the torque shaft is provided on the top pressure plate, a guide column which is inserted into the adjusting long hole to drive the top pressure plate to rotate is provided on the corresponding end surface of the adjusting rod, and the axis of the guide column is eccentrically arranged with the axis of the adjusting rod; the first transmission structure includes an input gear arranged on the transmission shaft, a shaft sleeve is rotatably arranged on the power output shaft, the shaft sleeve has a concentric section at the upper end which is coaxial with the shaft sleeve and an eccentric section at the lower end, a main gear is synchronously rotated on the concentric section, and an auxiliary gear is synchronously rotated on the eccentric section The second transmission structure includes a conversion gear rotatably arranged on the housing, the conversion gear has an inner gear ring structure meshing with the auxiliary gear, the inner gear ring structure and the auxiliary gear form a small tooth difference planetary gear transmission, and the conversion gear also has an outer gear ring structure; the second transmission structure also includes a worm gear that is rotatably and axially guided and moved in the housing and is used to cooperate with the outer gear ring structure, the worm gear is elastically installed by a second spring to realize horizontal elastic movement, an annular groove is arranged on the worm gear, and a shift fork that is engaged with the annular groove along the axial direction of the worm gear is arranged at the lower end of the torque shaft, so that the torque shaft can be driven to rotate by the shift fork when the worm gear moves axially;The housing is provided with a travel limit structure, which includes a second push rod which is elastic and guides movement and is provided on each valve block and can open and block the valve channel.

[0010] A hand wheel is arranged at the end of the worm extending out of the housing.

[0011] The stroke limiting structure also includes a mounting frame, on which a pressing cam is rotatably provided for pressing and cooperating with the corresponding second push rod, each pressing cam is rotatably installed on the mounting frame through a camshaft, each camshaft is provided with a first gear, and a power shaft is also rotatably provided on the mounting frame, on which a second gear is provided, the first gear and the second gear are transmitted through a gear set, a third gear is provided at the lower end of the power shaft, and a fourth gear meshing with the third gear is provided on the power output shaft.

[0012] The valve channels on each of the valve blocks include a main valve channel, and the valve block is also provided with a secondary valve channel arranged parallel to the main valve channel, a first connecting valve channel and a second connecting valve channel are arranged between the main valve channel and the secondary valve channel, the first connecting valve channel and the second connecting valve channel are connected through the connecting valve channel, a movable valve core is arranged in the secondary valve channel to guide and move between the first connecting valve channel and the second connecting valve channel, a first mounting cavity is arranged on the first connecting valve channel for installation of a first push rod, and a second mounting cavity is arranged on the second connecting valve channel for installation of a second push rod, and an intermediate valve channel connecting the main valve channel and the secondary valve channel is also provided on the valve block, a blocking column is installed in the intermediate valve channel for guiding and moving up and down and movably sealing, the lower end of the blocking column has an annular cutting groove for gas on both sides of the main valve channel to pass through, the blocking column also has a stopping portion that blocks the main valve channel after moving, a first valve core connecting hole connecting the intermediate valve channel and the first connecting valve channel is arranged at one end of the valve core, and a second valve core connecting hole connecting the intermediate valve channel and the second connecting valve channel is arranged at the other end of the valve core.

[0013] Each installation cavity includes a guide installation section and a connecting section, each connecting section is sealed with a fixed block, each fixed block has a fixed block cavity and a central through hole, a main valve channel connecting cavity connected to the main valve channel is formed between the fixed block and the connecting section, a sealing plate that cooperates with the central through hole of the fixed block is elastically arranged in the main valve channel connecting cavity, each push rod includes a guide sealing part that guides and moves and is sealed in the installation section, a pushing part is arranged at the end of the guide sealing part, a fourth spring is arranged between the pushing part and the fixed block, the diameter of the pushing part is smaller than the diameter of the central through hole of the fixed block, and is used to push the sealing plate to allow gas to pass.

[0014] The beneficial effects of the present invention are as follows: when the valve stem is stuck and cannot be closed or opened, the gas pressure in the pneumatic motor is constantly increasing, causing the torque of the power output shaft to constantly increase. The torque shaft can be driven to rotate through the second transmission structure, and the top pressure structure at the upper end of the torque shaft will push the corresponding first push rod to block the valve channel on the corresponding valve block, so as to cut off the air source supplying air to the pneumatic motor, thereby avoiding the problem of the valve stem continuing to be subjected to force and causing bending or breakage. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 is a schematic structural diagram of a pneumatic drive mechanism in an embodiment of a valve of the present invention;

[0016] Figure 2 yes Figure 1 Schematic diagram of the structure inside the middle shell Figure 1 ;

[0017] Figure 3 yes Figure 2 A partial enlarged view of the middle A;

[0018] Figure 4 yes Figure 2 A partial enlarged view of point B in the middle;

[0019] Figure 5 yes Figure 2 Structural schematic diagram of the middle top pressure structure;

[0020] Figure 6 yes Figure 1 Schematic diagram of the structure inside the middle shell Figure 2 ;

[0021] Figure 7 yes Figure 6 A partial enlarged view of point C in the middle;

[0022] Figure 8 yes Figure 6 A schematic diagram of the structure of the first transmission structure and the second transmission structure;

[0023] Fig. 9 It is a schematic diagram of the structure of the valve channel in the valve block;

[0024] Fig.10 Schematic diagram of the structure of the first push rod. DETAILED DESCRIPTION

[0025] An embodiment of a valve of the present invention, such as Figure 1-Figure 10As shown, it includes a valve body, a valve seat and a valve plate are arranged in the valve body, a valve stem is connected to the valve plate, and a pneumatic drive mechanism for driving the valve stem to rotate. The pneumatic drive mechanism includes a shell 1, and a power output shaft 43 is rotatably arranged on the shell 1. A pneumatic motor 8 is arranged on the shell, and a shell air inlet 2 and a shell air outlet 3 are arranged on the shell. The pneumatic motor has a motor air inlet and a motor air outlet. The shell air inlet is connected to the motor air inlet through an air inlet pipe 4, and the shell air outlet is connected to the motor air outlet through an air outlet pipe 5. The transmission shaft 31 of the pneumatic motor is connected to the power output shaft 43 through a first transmission structure. A first valve block 9 is arranged on the air inlet pipe in the shell, and a second valve block 10 is arranged on the air outlet pipe in the shell. Each valve block is provided with a valve channel connected to the corresponding air pipe. In order to facilitate the neat arrangement of the air inlet and outlet pipes, the housing is also provided with an intermediate air inlet 6 and an intermediate air outlet 7. The air inlet and outlet pipes each include three sections. The air inlet includes a first section connecting the air inlet of the housing and the first valve block, a second section connecting the first valve block and the intermediate air inlet, and a third section connecting the intermediate air inlet and the motor air inlet. The air outlet pipe also includes the above three corresponding sections. A gas connector is provided at each air inlet and outlet.

[0026] Each valve block is elastically and guided to move with a first push rod 28 capable of opening and blocking the corresponding valve channel. A torque switch 17 is also provided in the housing. The torque switch 17 includes a torque shaft 18 rotatably provided on the housing. The end of the torque shaft is provided with a pressing structure for pressing with the first push rod on the corresponding valve block. The power output shaft and the torque shaft are connected by a second transmission structure, so that when the valve is stuck and cannot be opened or closed, the power output shaft can drive the torque shaft to rotate so that the corresponding first push rod closes the valve channel of the corresponding valve block. The pressing structure, such as Figure 3 and Figure 5 As shown, it includes a mounting sleeve 19 that can be synchronously rotated and arranged on the torque shaft, and a lug 20 is arranged on the outer wall of the mounting sleeve. The lug has an arc end 21, and the lower side of the arc end is provided with multiple slots 22 at intervals along the circumferential direction. An adjusting rod 24 is movably installed on the lug, and a block 25 that is engaged with the circumferential engagement of the slot is arranged at the end of the adjusting rod. A first spring (not shown in the figure) is arranged between the adjusting rod and the lug to achieve the engagement of the block with the slot. In this embodiment, a cover plate is arranged on the lug, and a through hole for the adjusting rod to be installed is arranged on the cover plate. One end of the first spring presses against the cover plate, and the other end presses against the upper end head of the adjusting rod. The pressing structure also includes a pressing plate 23 that is rotatably arranged on the torque shaft, and an adjusting long hole 26 whose length points to the axis of the torque shaft is arranged on the pressing plate. A guide column 27 that is inserted into the adjusting long hole to drive the pressing plate to rotate is arranged on the corresponding end face of the adjusting rod, and the axis of the guide column is eccentrically arranged with the axis of the adjusting rod. The torque can be adjusted by rotating the top pressure plate position and the adjusting rod position.

[0027] The first transmission structure includes an input gear 32 arranged on a transmission shaft 31, a sleeve 33 is rotatably arranged on a power output shaft 43, the sleeve has a concentric section 44 arranged coaxially with the sleeve at the upper end and an eccentric section 45 at the lower end, a main gear 14 is synchronously rotatably arranged on the concentric section, and an auxiliary gear 15 is synchronously rotatably installed on the eccentric section. A transmission plate 46 is also synchronously rotatably arranged on the power output shaft, and a third transmission structure for driving the transmission plate to rotate is arranged on the auxiliary gear. A plurality of transmission holes 47 are arranged at intervals along the circumferential direction on the transmission plate, and the third transmission structure includes a transmission rod 48 corresponding to each transmission hole arranged on the auxiliary gear 15, each transmission rod is provided with a rotating sleeve 49, the rotating sleeve is located in the corresponding transmission hole, and the transmission rod drives the transmission plate to rotate through the transmission sleeve. The second transmission structure includes a conversion gear 16 rotatably arranged on the housing, the conversion gear has an inner gear ring structure 34 meshing with the auxiliary gear for transmission, the inner gear ring structure and the auxiliary gear form a small tooth difference planetary gear transmission, and the conversion gear also has an outer gear ring structure 35. The second transmission structure also includes a worm 11 that is rotatable and axially guided and moved in the housing for cooperating with the outer gear ring structure. The worm is elastically mounted by a second spring 12 to achieve horizontal elastic movement. The worm is provided with an annular groove 29, such as Figure 4 As shown, the lower end of the torque shaft is provided with a shift fork 30 that engages with the annular groove along the axial direction of the worm, so that the shift fork drives the torque shaft to rotate when the worm moves axially. The end of the worm extending out of the housing is provided with a hand wheel 13, which can realize manual opening and closing of the valve.

[0028] A travel limit structure is provided in the housing, such as Figure 7 As shown, the stroke limit structure includes a second push rod 38 that is elastically and guideably arranged on each valve block and can open and block the valve channel. The stroke limit structure also includes a mounting frame, on which a pressing cam 41 for pressing and cooperating with the corresponding second push rod is rotatably arranged. Each pressing cam is rotatably mounted on the mounting frame through a camshaft 39, and each camshaft is provided with a first gear 40. A power shaft is also rotatably arranged on the mounting frame, on which a second gear is arranged, and the first gear and the second gear are driven by a gear set 42. A third gear 37 is arranged at the lower end of the power shaft, and a fourth gear 36 that meshes and drives with the third gear is arranged on the power output shaft. When the power output shaft rotates beyond the formation, under the action of the fourth gear and the third gear, the pressing cam will push the corresponding second push rod into the corresponding valve block to cut off the gas source. In the prior art, the stroke limit structure and the pneumatic motor are respectively controlled by two separate gas circuits, so that the gas circuit is complicated and the piping is complicated, resulting in many joints in the air pipe, and air leakage is easy to occur at the air pipe joint, affecting the use effect. In this embodiment, by setting the first valve block and the second valve block, the two sets of gas circuits in the prior art can be realized through one set of gas circuit, which reduces the number of piping and gas pipe joints, greatly reduces the risk of gas leakage in the gas pipe joints, and is safe and beautiful.

[0029] The valve channels on each valve block include a main valve channel 50, such as Fig. 9 As shown, the valve block is also provided with an auxiliary valve channel 51 arranged in parallel with the main valve channel, and a first connecting valve channel 53 and a second connecting valve channel 54 are arranged between the main valve channel and the auxiliary valve channel, and the first connecting valve channel and the second connecting valve channel are connected through a connecting valve channel 55. A movable valve core 52 is provided in the auxiliary valve channel to guide and move between the first connecting valve channel and the second connecting valve channel. A first installation cavity 56 is provided on the first connecting valve channel for installation of the first push rod 28, and a second installation cavity 57 is provided on the second connecting valve channel for installation of the second push rod 38. The valve block is also provided with an intermediate valve channel 58 connecting the main valve channel 50 and the auxiliary valve channel 51, and a blocking column 59 is installed in the intermediate valve channel for guiding and moving up and down and movably sealing, and the lower end of the blocking column has an annular cutting groove 60 for gas on both sides of the main valve channel to pass through, and the blocking column also has a blocking portion 70 for blocking the main valve channel after movement. A first valve core connecting hole 61 connecting the middle valve channel with the first connecting valve channel is disposed at one end of the valve core, and a second valve core connecting hole 71 connecting the middle valve channel with the second connecting valve channel is disposed at the other end of the valve core.

[0030] Each installation cavity includes a guide installation section 72 and a connecting section 73. Fig.10 As shown, each connecting section is sealed with a fixed block 62, and each fixed block has a fixed block cavity 63 and a central through hole 64. A main valve channel connecting cavity connected to the main valve channel is formed between the fixed block and the connecting section, and a sealing plate 65 is elastically provided in the main valve channel connecting cavity through a third spring 66 to cooperate with the central through hole of the fixed block to block. Each push rod includes a guide sealing part 67 that guides and moves and is sealed and installed in the installation section, and a push part 68 is provided at the end of the guide sealing part. A fourth spring 69 is provided between the push part and the fixed block, and the diameter of the push part is smaller than the aperture of the central through hole of the fixed block, which is used to push the sealing plate to allow gas to pass. Whether the first push rod or the second push rod is pushed into the corresponding valve block, the gas in the main valve channel will enter the secondary valve channel, push the valve core to allow the gas to enter the middle valve channel, and the gas pushes the stop column downward, so that the stop part of the stop column blocks the main valve channel, so as to cut off the gas source of the air supply to the pneumatic motor.

[0031] During use, when the valve stem is stuck and cannot be closed or opened, the gas pressure in the pneumatic motor is constantly increasing, causing the torque of the power output shaft to constantly increase. The worm is rotated axially by the conversion gear in the second transmission structure. Since the worm has a self-locking function, the worm will not rotate and can only move axially. The annular groove on the worm will drive the shift fork on the torque shaft to rotate, thereby driving the torque shaft to rotate. The top pressure plate at the upper end of the torque shaft will push the corresponding first push rod to block the valve channel on the corresponding valve block to cut off the air source to supply air to the pneumatic motor, avoiding the problem of the valve stem being bent or broken due to continued force. Moreover, the present invention improves the stroke limit structure and the pneumatic motor in the prior art to be controlled separately by two separate air circuits, and improves it to be realized by one set of air circuits, thereby simplifying the air circuit, reducing piping and gas joints, and reducing the risk of air leakage at the air pipe joints. It is safe and beautiful.

[0032] In other embodiments of the present invention, the torque switch can also be designed to have non-adjustable torque. In this case, the adjusting rod, lug and other structures are omitted, and only a top pressure plate needs to be set on the torque rotation shaft. In this case, the long hole may not be set on the top pressure plate; the intermediate air inlet and the intermediate air outlet may not be set on the shell. In this case, an air intake pipe mounting hole for the air intake pipe to pass through and an air outlet pipe mounting hole for the air outlet pipe to pass through can be set on the shell at the same position as the intermediate air inlet and the intermediate air outlet.

[0033] An embodiment of a pneumatic drive mechanism of the present invention is the same as the embodiments of the pneumatic drive mechanisms of the above-mentioned valve, and will not be described in detail here.

Claims

1. A pneumatic drive mechanism, comprising a housing, a power output shaft rotatably arranged on the housing, a pneumatic motor arranged on the housing, a housing air inlet and a housing air outlet arranged on the housing, the pneumatic motor having a motor air inlet and a motor air outlet, the housing air inlet being connected to the motor air inlet through an air inlet pipe, the housing air outlet being connected to the motor air outlet through an air outlet pipe, the transmission shaft of the pneumatic motor being connected to the power output shaft through a first transmission structure; characterized in that: A first valve block is arranged on the air inlet pipe in the shell, a second valve block is arranged on the air outlet pipe in the shell, each valve block is arranged with a valve channel connected with the corresponding air pipe, each valve block is elastically and guided to move with a first push rod capable of opening and blocking the corresponding valve channel; a torque switch is also arranged in the shell, the torque switch comprises a torque shaft rotatably arranged on the shell, and a pressing structure for pressing and cooperating with the first push rod on the corresponding valve block is arranged at the end of the torque shaft; the power output shaft and the torque shaft are connected by a second transmission structure, so that when the valve is stuck and cannot be opened or closed, the power output shaft can drive the torque shaft to rotate to make the corresponding first push rod A push rod closes the valve channel of the corresponding valve block; the top pressure structure includes a mounting sleeve that can be synchronously rotated and arranged on the torque shaft, a lug is arranged on the outer wall of the mounting sleeve, the lug has an arc end, and a plurality of slots are arranged at intervals along the circumferential direction on the lower side surface of the arc end, an adjusting rod is movably installed on the lug, a block that cooperates with the circumferential clamp of the slot is arranged at the end of the adjusting rod, a first spring is arranged between the adjusting rod and the lug, the top pressure structure also includes a top pressure plate that is rotatably arranged on the torque shaft, an adjusting long hole whose length points to the axis of the torque shaft is arranged on the top pressure plate, and a guide inserted into the adjusting long hole to drive the top pressure plate to rotate is arranged on the corresponding end surface of the adjusting rod. The axis of the guide column is eccentrically arranged with the axis of the adjusting rod; the first transmission structure includes an input gear arranged on the transmission shaft, a sleeve is rotatably arranged on the power output shaft, the sleeve has a concentric section at the upper end that is coaxial with the sleeve and an eccentric section at the lower end, a main gear is synchronously rotated on the concentric section, an auxiliary gear is synchronously installed on the eccentric section, a transmission sheet is also synchronously rotated on the power output shaft, and a third transmission structure that drives the transmission sheet to rotate is arranged on the auxiliary gear; the second transmission structure includes a conversion gear rotatably arranged on the housing, the conversion gear has an inner gear ring structure that meshes with the auxiliary gear for transmission, and the inner gear ring structure is meshed with the auxiliary gear. The auxiliary gear forms a planetary gear transmission with a small tooth difference, and the conversion gear also has an outer ring gear structure; the second transmission structure also includes a worm that is rotatable and can be axially guided and moved in the housing for cooperating with the outer ring gear structure, and the worm is elastically installed by a second spring to achieve horizontal elastic movement, and an annular groove is provided on the worm, and a shift fork that is engaged with the annular groove along the axial direction of the worm is provided at the lower end of the torque shaft, so that the torque shaft is driven to rotate by the shift fork when the worm moves axially; a stroke limiting structure is provided in the housing, and the stroke limiting structure includes a second push rod that is elastically and guided to move and is arranged on each valve block and can open and block the valve path.

2. The pneumatic drive mechanism according to claim 1, characterized in that: A hand wheel is arranged at the end of the worm extending out of the housing.

3. The pneumatic drive mechanism according to claim 1, characterized in that: The stroke limiting structure also includes a mounting frame, on which a pressing cam is rotatably provided for pressing and cooperating with the corresponding second push rod, each pressing cam is rotatably installed on the mounting frame through a camshaft, each camshaft is provided with a first gear, and a power shaft is also rotatably provided on the mounting frame, on which a second gear is provided, the first gear and the second gear are transmitted through a gear set, a third gear is provided at the lower end of the power shaft, and a fourth gear meshing with the third gear is provided on the power output shaft.

4. The pneumatic drive mechanism according to claim 1, characterized in that: The valve channels on each of the valve blocks include a main valve channel, and the valve block is also provided with a secondary valve channel arranged parallel to the main valve channel, a first connecting valve channel and a second connecting valve channel are arranged between the main valve channel and the secondary valve channel, the first connecting valve channel and the second connecting valve channel are connected through the connecting valve channel, a movable valve core is arranged in the secondary valve channel to guide and move between the first connecting valve channel and the second connecting valve channel, a first mounting cavity is arranged on the first connecting valve channel for installation of a first push rod, and a second mounting cavity is arranged on the second connecting valve channel for installation of a second push rod, and an intermediate valve channel connecting the main valve channel and the secondary valve channel is also provided on the valve block, a blocking column is installed in the intermediate valve channel for guiding and moving up and down and movably sealing, the lower end of the blocking column has an annular cutting groove for gas on both sides of the main valve channel to pass through, the blocking column also has a stopping portion that blocks the main valve channel after moving, a first valve core connecting hole connecting the intermediate valve channel and the first connecting valve channel is arranged at one end of the valve core, and a second valve core connecting hole connecting the intermediate valve channel and the second connecting valve channel is arranged at the other end of the valve core.

5. The pneumatic drive mechanism according to claim 4, characterized in that: Each installation cavity includes a guide installation section and a connecting section, each connecting section is sealed with a fixed block, each fixed block has a fixed block cavity and a central through hole, a main valve channel connecting cavity connected to the main valve channel is formed between the fixed block and the connecting section, a sealing plate that cooperates with the central through hole of the fixed block is elastically arranged in the main valve channel connecting cavity, each push rod includes a guide sealing part that guides and moves and is sealed in the installation section, a pushing part is arranged at the end of the guide sealing part, a fourth spring is arranged between the pushing part and the fixed block, the diameter of the pushing part is smaller than the diameter of the central through hole of the fixed block, and is used to push the sealing plate to allow gas to pass.

6. A valve, comprising a valve body, a valve seat and a valve plate arranged in the valve body, a valve stem connected to the valve plate, and a pneumatic drive mechanism for driving the valve stem to rotate, characterized in that: The pneumatic drive mechanism adopts the pneumatic drive mechanism described in any one of claims 1-5.

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