A one-way high torque actuator with switch double limit function and segmented travel

Abstract

The present invention relates to the technical field of actuators for opening and closing valves, and discloses a unidirectional large torque actuator with a segmented stroke and a double limit function of a switch, comprising an auxiliary cylinder module, a cylinder module, and a valve drive module which are arranged in sequence, wherein the auxiliary cylinder module comprises a front cylinder head, an intermediate cylinder head, and an auxiliary piston, and the cylinder module comprises a rear cylinder head which is located on one side of the intermediate cylinder head and is coaxially arranged with the intermediate cylinder head, and a main piston which is movably installed between the intermediate cylinder head and the rear cylinder head. The actuator has a double limit protection mechanism to ensure that the actuator can stop accurately when reaching a predetermined position to avoid problems of over-positioning or under-positioning; has a large torque output capacity, is suitable for high-torque drive occasions, while maintaining high efficiency and low noise, and prolongs the service life of the actuator; has a segmented control function, can enable the piston to be accurately controlled according to a plurality of preset positions, realizes a segmented stroke, and is suitable for occasions requiring a complex stroke.

Description

Technical Field

[0001] The invention relates to the technical field of valve opening and closing actuators, in particular to a one-way large torque actuator with a segmented stroke and a double-limiting function of a switch. Background Art

[0002] The valve actuator is a key component of the valve system. It is responsible for opening, closing or adjusting the valve according to the control signal. It can not only realize the automatic control of the valve, improve production efficiency and product quality, but also extend the service life of the equipment and reduce the risk of manual operation. Valve actuators have been widely used in industrial automation, petrochemical, municipal construction, tap water systems, air conditioning and ventilation, etc.

[0003] After searching, the patent with application number CN201910718285.5 is a valve pneumatic actuator, including left and right end covers, a cylinder sealing ring, a piston sealing ring, a cylinder body, a gear shaft assembly, a piston and two adjusting bolt assemblies, the gear shaft assembly is installed in the middle of the cylinder body, and the two pistons are respectively installed from the two ends of the cylinder body to mesh with the gear shaft assembly, the piston sealing ring is sleeved in the O-ring sealing groove on the outer wall of the piston, and the inner ends of the left and right end covers are installed with cylinder sealing rings, and the cylinder sealing ring is sealed with the cylinder body. The left and right end covers are respectively fixed at the two ends of the cylinder body with four bolts, and the two adjusting bolt assemblies are installed on the rear side of the cylinder body and cooperate with the adjusting block of the gear shaft assembly to adjust the degree of opening and closing of the valve; Beneficial effects: the cylinder body, the end cover and the piston are all injection molded by plastic material, the parts do not need to be processed and the weight is about 50% lighter than that of aluminum alloy materials, especially the tolerance and roughness of the sealing surface can be guaranteed, the production efficiency is high, and the manufacturing cost is low.

[0004] The current pneumatic actuators used to drive the opening and closing of valves are generally equipped with only one cylinder (with only one piston inside), and the movement of the piston is a single stroke, which is not convenient for controlling the precise position of the piston inside the cylinder, that is, it is not convenient to grasp the precise opening and closing position of the valve, and is not suitable for occasions with complex strokes; and the output torque of the single piston setting has certain limitations, and is not suitable for high-torque drive occasions. Therefore, we need to propose a unidirectional high-torque actuator with a segmented stroke and a double limit function of the switch. Summary of the invention

[0005] The purpose of the present invention is to provide a unidirectional large torque actuator with a segmented stroke and a double limit function of a switch, which has a double limit protection mechanism to ensure that the actuator can stop accurately when reaching a predetermined position to avoid the problem of over-positioning or under-positioning; it has a large torque output capacity and is suitable for high-torque drive occasions, while maintaining high efficiency and low noise, extending the service life of the actuator; it has a segmented control function, which allows the piston to be accurately controlled according to multiple preset positions to achieve a segmented stroke, and is suitable for occasions requiring a complex stroke to solve the problems raised in the above background technology.

[0006] To achieve the above-mentioned purpose, the present invention provides the following technical solutions: a unidirectional large torque actuator with a switch double limit function and a segmented stroke, comprising an auxiliary cylinder module, a cylinder module, and a valve drive module arranged in sequence, wherein the auxiliary cylinder module comprises a coaxially arranged front cylinder head, an intermediate cylinder head, and an auxiliary piston movably installed between the front cylinder head and the intermediate cylinder head, the cylinder module comprises a rear cylinder head located at one side of the intermediate cylinder head and coaxially arranged with the intermediate cylinder head, and a main piston movably installed between the intermediate cylinder head and the rear cylinder head, wherein the diameter of the auxiliary piston is greater than the diameter of the main piston;

[0007] It also includes a main shaft that passes through the auxiliary cylinder module, the cylinder module, and the valve drive module, and the auxiliary piston and the main piston are both slidably mounted on the outer wall of the main shaft;

[0008] The valve drive module includes a box body, in which a cylinder for plugging in a rotating shaft is rotatably installed inside the box body, two aligned crank arms are welded on the outer wall of the cylinder, a guide block is movably installed between the two crank arms, the bottom end of the main shaft is connected to the guide block, and a switch double limit mechanism for sharing the collision force when the crank arm is forced to contact the limit bolt is installed on the side baffle of the box body.

[0009] Preferably, a first connecting column fixed by a nut is connected between the front cylinder head and the middle cylinder head, and a second connecting column fixed by a nut is connected between the middle cylinder head and the rear cylinder head, and a plurality of the first connecting columns and the second connecting columns are arranged equidistantly in a ring shape.

[0010] Preferably, a first protective cover is installed between the front cylinder head and the middle cylinder head, a second protective cover is installed between the middle cylinder head and the rear cylinder head, the outer wall of the auxiliary piston is attached to the inner wall of the first protective cover, and the outer wall of the main piston is attached to the outer wall of the second protective cover.

[0011] Preferably, the front cylinder head is provided with a first air hole, the middle cylinder head is provided with a second air hole, and the rear cylinder head is provided with a third air hole.

[0012] Preferably, a limiting boss 1 is integrally formed on one side of the front cylinder head, and a limiting boss 2 is integrally formed on one side of the middle cylinder head. The outer wall of the limiting boss 1 is attached to the upper end of the inner wall of the first protective cover, and the outer wall of the limiting boss 2 is attached to the lower end of the outer wall of the first protective cover.

[0013] Preferably, a limiting boss three is integrally formed on the other side of the middle cylinder head, and a limiting boss four is integrally formed on one side of the rear cylinder head. The outer wall of the limiting boss three is attached to the upper end of the inner wall of the second protective cover, and the outer wall of the limiting boss four is attached to the lower end of the outer wall of the second protective cover.

[0014] Preferably, the outer walls of the limiting boss three and the outer walls of the limiting boss four are both provided with an annular first notch, a first sealing ring is arranged inside the first notch, and the first sealing ring is attached to both ends of the inner wall of the second protective cover.

[0015] Preferably, a connecting ring is installed on the outer wall of the main piston, a second notch is opened on the outer wall of the connecting ring, a second sealing ring is installed inside the second notch, and the second sealing ring is attached to the middle position of the inner wall of the second protective cover.

[0016] Preferably, a large flange is installed on one side of the box body, a box cover is installed on the other side of the box body, small flanges are installed on both the box body and the box cover, and the cylinder is rotatably installed between the two small flanges;

[0017] The guide block is respectively provided with a first through hole, a slot and a second through hole, a guide column penetrating the second through hole is fixed inside the box, the main shaft is inserted into the slot, a rotating column is rotatably installed inside the first through hole, sliders are installed at both ends of the rotating column, a limiting hole is provided on the crank arm, and the slider is slidably installed inside the limiting hole.

[0018] Preferably, a support is installed on the limiting boss four, and a buffer mechanism for buffering the movement of the main piston is installed on the support. The buffer mechanism includes a circular ring, multiple springs connected to one side of the circular ring, and multiple limiting columns. One end of the spring is connected to the support, and a limiting groove is provided on the support. The limiting column is movably installed inside the limiting groove.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] 1. The present invention has a double limit protection mechanism to ensure that the actuator can stop accurately when it reaches the predetermined position, avoiding the problem of over-positioning or under-positioning;

[0021] 2. The present invention has a large torque output capacity and is suitable for high torque drive occasions, while maintaining high efficiency and low noise, extending the service life of the actuator;

[0022] 3. The present invention has the function of segmented control, which enables the piston to be accurately controlled according to multiple preset positions to achieve segmented stroke, and is suitable for occasions requiring complex strokes. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a structural schematic diagram of the present invention;

[0024] Figure 2 It is a schematic diagram of the internal structure of the present invention;

[0025] Figure 3 A schematic diagram of the structure of the cylinder module, auxiliary cylinder module and crank arm of the present invention;

[0026] Figure 4 It is a schematic diagram of the structure of the crank arm, cylinder and guide block of the present invention;

[0027] Figure 5 It is a schematic diagram of the structure of the crank arm and the cylinder of the present invention;

[0028] Figure 6 A schematic diagram of the structure of the guide block of the present invention;

[0029] Figure 7 It is a structural schematic diagram of the main piston and the auxiliary piston of the present invention;

[0030] Figure 8 It is a structural schematic diagram of the main piston, protective cover and rear cylinder cover of the present invention;

[0031] Fig. 9 It is a structural schematic diagram of the buffer mechanism of the present invention.

[0032] In the figure: 1, main shaft; 2, front cylinder head; 21, first air hole; 22, limiting boss 1; 3, middle cylinder head; 31, limiting boss 2; 32, second air hole; 33, limiting boss 3; 4, rear cylinder head; 41, limiting boss 4; 42, third air hole; 43, support; 431, limiting groove; 44, first missing groove; 5, first protective cover; 6, first connecting column; 7, second protective cover; 71, first sealing ring; 72, second sealing ring; 8, second connecting column; 9, box body; 10 , box cover; 101, switch double limit mechanism; 11, large flange; 12, auxiliary piston; 13, main piston; 131, connecting ring; 132, second notch; 14, small flange; 141, cylinder; 15, crank arm; 151, limit hole; 16, guide block; 161, rotating column; 162, slider; 163, first through hole; 164, slot; 165, second through hole; 19, guide column; 20, buffer mechanism; 201, ring; 202, spring; 203, limit column. DETAILED DESCRIPTION

[0033] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0034] See also Figure 1-Figure 9 The present invention provides a technical solution: a unidirectional large torque actuator with a switch double limit function and a segmented stroke, comprising an auxiliary cylinder module, a cylinder module, and a valve drive module which are arranged in sequence, wherein the cylinder module is a main cylinder, the auxiliary cylinder module comprises a coaxially arranged front cylinder cover 2, an intermediate cylinder cover 3, and an auxiliary piston 12 movably installed between the front cylinder cover 2 and the intermediate cylinder cover 3, and the front cylinder cover 2 and the intermediate cylinder cover 3 have the same diameter, the cylinder module comprises a rear cylinder cover 4 which is located at one side of the intermediate cylinder cover 3 and is coaxially arranged with the intermediate cylinder cover 3, and a main piston 13 which is movably installed between the intermediate cylinder cover 3 and the rear cylinder cover 4, wherein the diameter of the rear cylinder cover 4 is smaller than the diameter of the intermediate cylinder cover 3, and an auxiliary push rod which is sleeved on the main shaft 1 is installed on the main piston 13, and the auxiliary push rod is used to push the main piston 13 to move, and the diameter of the auxiliary piston 12 is larger than the diameter of the main piston 13;

[0035] The area of ​​the auxiliary cylinder module is twice the area of ​​the cylinder module.

[0036] Among them, the maximum cylinder diameter of the auxiliary cylinder module can be up to 1,300 mm, and the maximum output torque can reach 500,000 Nm.

[0037] This device has a switch limit adjustment function of ±5 degrees. The feedback shaft head conforms to the NAMUR standard, which is convenient for the installation of accessories such as position switches and positioners. The connection size at the bottom of the box conforms to the ISO 5211 standard, which is convenient for the connection of the valve.

[0038] It also includes a main shaft 1 that penetrates the auxiliary cylinder module, the cylinder module, and the valve drive module, and the auxiliary piston 12 and the main piston 13 are both slidably mounted on the outer wall of the main shaft 1;

[0039] The valve driving module includes a box body 9, and a cylinder 141 for plugging a rotating shaft is rotatably installed inside the box body 9. By driving the cylinder 141 to rotate, the rotating shaft is driven to rotate, thereby realizing the opening and closing of the valve. Two aligned curved arms 15 are welded on the outer wall of the cylinder 141. The curved arms 15 are arranged up and down. A guide block 16 is movably installed between the two curved arms 15. The guide block 16 is set to be a square guide block. The bottom end of the main shaft 1 is connected to the guide block 16, and the movement of the main shaft 1 drives the guide block 16 to move;

[0040] like Figure 1 and Figure 2As shown, a switch double limit mechanism 101 for sharing the collision force when the crank arm 15 is forced to contact the limit bolt is installed on the side baffle of the box body 9.

[0041] like Figure 5 As shown, the crank arm 15 is made by welding. Two special-shaped precision plates with limiting bosses of the same shape are processed with grooves and welded to a whole cylinder 141 at intervals. Stress relief heat treatment is performed and the limiting force-bearing surface is processed as a whole to ensure that the upper and lower surfaces are vertical and the force is evenly distributed.

[0042] The box body 9 adopts an open fully welded enhanced design. A switch double limit mechanism 101 is set on both sides of the front baffle of the box body 9. The switch double limit mechanism 101 is integrally embedded in the front baffle and welded. The force points are distributed up and down to share the impact force generated when the crank arm 15 is forced to contact the limit bolt.

[0043] A first connecting column 6 fixed by a nut is connected between the front cylinder head 2 and the middle cylinder head 3, and a second connecting column 8 fixed by a nut is connected between the middle cylinder head 3 and the rear cylinder head 4. Multiple first connecting columns 6 and second connecting columns 8 are arranged equidistantly in a ring shape.

[0044] Both ends of the first connecting column 6 penetrate the front cylinder cover 2 and the middle cylinder cover 3 respectively, and both ends of the first connecting column 6 are threadedly installed with nuts;

[0045] Both ends of the second connecting column 8 penetrate the middle cylinder cover 3 and the rear cylinder cover 4 respectively, and both ends of the second connecting column 8 are threadedly mounted with nuts.

[0046] It is worth noting that the first protective cover 5 is located between the plurality of first connecting pillars 6 , and the second protective cover 7 is located between the plurality of second connecting pillars 8 .

[0047] A first protective cover 5 is installed between the front cylinder head 2 and the middle cylinder head 3, and a second protective cover 7 is installed between the middle cylinder head 3 and the rear cylinder head 4. The outer wall of the auxiliary piston 12 is attached to the inner wall of the first protective cover 5, and the outer wall of the main piston 13 is attached to the outer wall of the second protective cover 7.

[0048] A closed space is formed between the front cylinder head 2 , the middle cylinder head 3 , and the first protective cover 5 , and a closed space is formed between the middle cylinder head 3 , the rear cylinder head 4 , and the second protective cover 7 .

[0049] The front cylinder head 2 is provided with a first air hole 21, the middle cylinder head 3 is provided with a second air hole 32, and the rear cylinder head 4 is provided with a third air hole 42. The first air hole 21, the second air hole 32, and the third air hole 42 are used for the passage of air flow, and the movement of the auxiliary piston 12 and the main piston 13 is achieved by controlling the direction of the air flow.

[0050] A limiting boss 22 is integrally formed on one side of the front cylinder head 2, and a limiting boss 31 is integrally formed on one side of the middle cylinder head 3. The outer wall of the limiting boss 22 is attached to the upper end of the inner wall of the first protective cover 5, and the outer wall of the limiting boss 31 is attached to the lower end of the outer wall of the first protective cover 5.

[0051] Sealing structures are provided between the outer wall of the limiting boss 1 22 and the inner wall of the first protective cover 5 , and between the outer wall of the limiting boss 2 31 and the inner wall of the first protective cover 5 , to ensure the sealing between the auxiliary cylinder modules.

[0052] A limiting boss three 33 is integrally formed on the other side of the middle cylinder head 3, and a limiting boss four 41 is integrally formed on one side of the rear cylinder head 4. The outer wall of the limiting boss three 33 is attached to the upper end of the inner wall of the second protective cover 7, and the outer wall of the limiting boss four 41 is attached to the lower end of the outer wall of the second protective cover 7, thereby ensuring the sealing between the auxiliary cylinder modules.

[0053] The outer wall of the limiting boss three 33 and the outer wall of the limiting boss four 41 are both provided with an annular first notch 44, and a first sealing ring 71 is arranged inside the first notch 44, and the first sealing ring 71 is attached to both ends of the inner wall of the second protective cover 7. The thickness of the first sealing ring 71 is not less than the depth of the first notch 44, and plays a role in sealing the second protective cover 7 and the limiting boss three 33 and the limiting boss four 41.

[0054] A connecting ring 131 is installed on the outer wall of the main piston 13, a second notch 132 is opened on the outer wall of the connecting ring 131, a second sealing ring 72 is installed inside the second notch 132, and the second sealing ring 72 is attached to the middle of the inner wall of the second protective cover 7. The thickness of the second sealing ring 72 is not less than the depth of the second notch 132, so as to ensure the air tightness of the cylinder module, prevent air leakage, and realize the effective transmission of air pressure thrust.

[0055] A large flange 11 is installed on one side of the box body 9. The maximum size of the large flange 11 is F80, which is suitable for large-diameter three-eccentric butterfly valves, large-diameter three-piece fixed ball valves, etc. A box cover 10 is installed on the other side of the box body 9. Small flanges 14 are installed on the box body 9 and the box cover 10, and the cylinder 141 is rotatably installed between the two small flanges 14; specifically, mounting holes are opened on the box cover 10 and the box body 9, and the small flange 14 is fixed inside the mounting hole by bolts.

[0056] The box cover 10 is made of a whole fine plate, covering the box body 9 in full size, and is fixed by equally spaced positioning pins and bolts on all sides. Bolt holes are set in the left and right directions of the side flange of the box body 9 (i.e., the large flange 11), and is connected to the cylinder head by bolts. It has a simple and generous appearance, a clear-cut shape, and does not require disassembly or maintenance.

[0057] The guide block 16 is respectively provided with a first through hole 163, a slot 164 and a second through hole 165. The first through hole 163 and the second through hole 165 are vertically arranged and staggered. A guide column 19 penetrating the second through hole 165 is fixed inside the housing 9, that is, the guide block 16 slides up and down on the guide column 19, the spindle 1 is inserted into the slot 164, and the movement of the spindle 1 drives the movement of the guide block 16. A rotating column 161 is rotatably installed inside the first through hole 163, and sliders 162 are installed at both ends of the rotating column 161. A limiting hole 151 is provided on the crank arm 15, and the slider 162 is slidably installed inside the limiting hole 151.

[0058] In addition, a square plate is fixed to the opposite sides of the two crank arms 15 by bolts, and the square plate covers the limiting hole 151 to ensure the stability of the movement of the slider 162 inside the limiting hole 151.

[0059] When the guide block 16 moves, it drives the slider 162 to move inside the limiting hole 151 , that is, the slider 162 pushes the crank arm 15 to rotate, thereby realizing the rotation of the cylinder 141 and the opening and closing of the valve.

[0060] A support 43 is installed on the limiting boss 41, and a buffer mechanism 20 is installed on the support 43 to buffer the movement of the main piston 13 to prevent the main piston 13 from moving too far and touching the support 43. The buffer mechanism 20 includes a ring 201, a plurality of springs 202 connected to one side of the ring 201, and a plurality of limiting columns 203. A soft silicone rubber cushion is installed on the ring 201, one end of the spring 202 is connected to the support 43, a limiting groove 431 is provided on the support 43, and the limiting column 203 is movably installed inside the limiting groove 431.

[0061] When the main piston 13 moves to a position close to the support 43, the main piston 13 contacts the silicone rubber cushion on the ring 201, thereby driving the ring 201 to squeeze the spring 202, and driving the limit column 203 to be inserted into the interior of the limit groove 431. The spring 202 is deformed, and the thrust of the main piston 13 during movement is converted into the elastic force of the spring 202, thereby preventing the main piston 13 from touching the support 43.

[0062] Similarly, in order to prevent the auxiliary piston 12 from moving too far and contacting the intermediate cylinder cover 3, a buffer mechanism 20 is also required to be installed on the intermediate cylinder cover 3. The buffer mechanism 20 has the same structure as the buffer mechanism 20 on the support 43, and will not be described in detail.

[0063] Through the above settings, the intermediate opening positioning function can be realized. It is customary to define the closed position as 0 degrees and the open position as 90 degrees. Any position in the middle can be positioned, that is, segmented travel.

[0064] During use, the rear cylinder head 4 is often ventilated so that the valve is initially in the closed position. When the front cylinder head 2 is ventilated, the auxiliary piston 12 moves toward the middle cylinder head 3 under the action of air force. Since the diameter of the auxiliary piston 12 is greater than the diameter of the main piston 13, the thrust generated by the auxiliary cylinder module is greater than the thrust generated by the cylinder module. At this time, the main piston 13 is forcibly pushed toward the rear cylinder head 4 by the auxiliary push rod, so that the valve moves to the middle position. Since the rear cylinder head 4 is often ventilated, the valve is in the middle position and will not be pushed by the pipeline medium, causing the middle position to be unstable.

[0065] When the valve needs to be fully opened, the middle cylinder head 3 is ventilated, the front cylinder head 2 remains ventilated, the rear cylinder head 4 is exhausted, and the valve is fully opened. When the valve needs to be closed to the middle position, the rear cylinder head 4 is ventilated, the middle cylinder head 3 is exhausted, and the front cylinder head 2 is ventilated. If the front cylinder head 2 loses air, the valve is fully closed.

[0066] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A one-way high torque actuator with a switch double limit function and segmented travel, characterized in that: The invention comprises an auxiliary cylinder module, a cylinder module and a valve drive module which are arranged in sequence, wherein the auxiliary cylinder module comprises a front cylinder head (2), a middle cylinder head (3) which are arranged coaxially, and an auxiliary piston (12) which is movably mounted between the front cylinder head (2) and the middle cylinder head (3); the cylinder module comprises a rear cylinder head (4) which is located on one side of the middle cylinder head (3) and is arranged coaxially with the middle cylinder head (3), and a main piston (13) which is movably mounted between the middle cylinder head (3) and the rear cylinder head (4); the diameter of the auxiliary piston (12) is greater than the diameter of the main piston (13); It also includes a main shaft (1) that passes through the auxiliary cylinder module, the cylinder module, and the valve drive module, and the auxiliary piston (12) and the main piston (13) are both slidably mounted on the outer wall of the main shaft (1); The valve drive module comprises a box body (9), a cylinder (141) for inserting a rotating shaft is rotatably installed inside the box body (9), two aligned crank arms (15) are welded on the outer wall of the cylinder (141), a guide block (16) is movably installed between the two crank arms (15), the bottom end of the main shaft (1) is connected to the guide block (16), and a switch double limit mechanism (101) for allocating the collision force when the crank arms (15) and the limit bolt are forced into contact is installed on the side baffle of the box body (9); The front cylinder head (2) is provided with a first air hole (21), the middle cylinder head (3) is provided with a second air hole (32), and the rear cylinder head (4) is provided with a third air hole (42); a limiting boss 4 (41) is integrally formed on one side of the rear cylinder head (4); A support (43) is mounted on the limiting boss 4 (41); a buffer mechanism (20) for buffering the movement of the main piston (13) is mounted on the support (43); the buffer mechanism (20) comprises a circular ring (201), a plurality of springs (202) connected to one side of the circular ring (201), and a plurality of limiting columns (203); one end of the spring (202) is connected to the support (43); a limiting groove (431) is provided on the support (43); and the limiting column (203) is movably mounted inside the limiting groove (431); When in use, the rear cylinder head (4) is always ventilated so that the valve is initially in the closed position. When the front cylinder head (2) is ventilated, the auxiliary piston (12) moves toward the middle cylinder head (3) under the action of air force. Since the diameter of the auxiliary piston (12) is greater than the diameter of the main piston (13), the thrust generated by the auxiliary cylinder module is greater than the thrust generated by the cylinder module. At this time, the main piston (13) is forcibly pushed toward the rear cylinder head (4) by the auxiliary push rod, so that the valve moves to the middle position. Since the rear cylinder head (4) is always ventilated, the valve is in the middle position and will not be pushed by the pipeline medium to cause instability in the middle position. When the valve needs to be fully opened, the middle cylinder head (3) is ventilated, the front cylinder head (2) remains ventilated, the rear cylinder head (4) is exhausted, and the valve is fully opened; when the valve needs to be closed to the middle position, the rear cylinder head (4) is ventilated, the middle cylinder head (3) is exhausted, and the front cylinder head (2) is ventilated. If the front cylinder head (2) loses air, the valve is fully closed.

2. A one-way high torque actuator with a switch double limit function and segmented travel according to claim 1, characterized in that: A first connecting column (6) fixed by a nut is connected between the front cylinder head (2) and the middle cylinder head (3), and a second connecting column (8) fixed by a nut is connected between the middle cylinder head (3) and the rear cylinder head (4), wherein a plurality of the first connecting column (6) and the second connecting column (8) are arranged in an annular shape and at equal intervals.

3. A one-way high torque actuator with a switch double limit function and segmented travel according to claim 1, characterized in that: A first protective cover (5) is installed between the front cylinder head (2) and the middle cylinder head (3), a second protective cover (7) is installed between the middle cylinder head (3) and the rear cylinder head (4), an outer wall of the auxiliary piston (12) is attached to an inner wall of the first protective cover (5), and an outer wall of the main piston (13) is attached to an outer wall of the second protective cover (7).

4. A one-way high torque actuator with a switch double limit function and segmented travel according to claim 1, characterized in that: A limiting boss 1 (22) is integrally formed on one side of the front cylinder head (2), and a limiting boss 2 (31) is integrally formed on one side of the middle cylinder head (3), wherein the outer wall of the limiting boss 1 (22) is affixed to the upper end of the inner wall of the first protective cover (5), and the outer wall of the limiting boss 2 (31) is affixed to the lower end of the outer wall of the first protective cover (5).

5. According to claim 1, a one-way high torque actuator with a switch double limit function and segmented travel, characterized in that: The other side of the middle cylinder cover (3) is integrally formed with a limiting boss three (33), the outer wall of the limiting boss three (33) is fitted to the upper end of the inner wall of the second protective cover (7), and the outer wall of the limiting boss four (41) is fitted to the lower end of the outer wall of the second protective cover (7).

6. A one-way high torque actuator with a switch double limit function and segmented travel according to claim 5, characterized in that: The outer wall of the limiting boss three (33) and the outer wall of the limiting boss four (41) are both provided with an annular first notch (44), a first sealing ring (71) is arranged inside the first notch (44), and the first sealing ring (71) is fitted on both ends of the inner wall of the second protective cover (7).

7. A one-way high torque actuator with a switch double limit function and segmented travel according to claim 6, characterized in that: A connecting ring (131) is installed on the outer wall of the main piston (13), a second notch (132) is formed on the outer wall of the connecting ring (131), a second sealing ring (72) is installed inside the second notch (132), and the second sealing ring (72) is fitted to the middle part of the inner wall of the second protective cover (7).

8. The one-way high torque actuator with a switch double limit function and segmented travel according to claim 1, characterized in that: A large flange (11) is installed on one side of the box body (9), a box cover (10) is installed on the other side of the box body (9), small flanges (14) are installed on both the box body (9) and the box cover (10), and the cylinder (141) is rotatably installed between the two small flanges (14); The guide block (16) is respectively provided with a first through hole (163), a slot (164) and a second through hole (165); a guide column (19) penetrating the second through hole (165) is fixed inside the box body (9); the main shaft (1) is inserted into the slot (164); a rotating column (161) is rotatably mounted inside the first through hole (163); sliders (162) are mounted at both ends of the rotating column (161); a limiting hole (151) is provided on the crank arm (15); and the slider (162) is slidably mounted inside the limiting hole (151).

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