A double-cylinder three-piston valve pneumatic actuator

Abstract

The invention discloses a double-cylinder three-piston valve pneumatic actuator, the technical scheme of which is as follows: a shell is provided with a partition chamber, an inner piston is provided in the partition chamber, a transverse groove, a threaded groove and a transition groove are provided on the outer wall of the gear shaft, the inner piston is provided with a sliding rod with one end inserted into the transverse groove, two ventilation pipes respectively provided on the same side of the left piston and the right piston are connected to the outside of the shell, an upper hole is provided on the top of the partition chamber, two top blocks are provided on the outer wall of the partition chamber, sealing sleeves and a first spring are both provided on the outside of the two top blocks, a transition chamber for pushing the sealing sleeve to move, a check chamber connected to the transition chamber, a check piece facing the corresponding top block and a second spring for pushing the check piece toward the corresponding top block are provided on the left piston and the right piston, air inlet holes are provided on the outer walls of the two check chambers, transition holes are provided on the two top blocks, and grooves are provided for the idling of the gear shaft, thereby solving the problems of large installation space required and easy deformation of the racks in the prior art.

Description

Technical Field

[0001] The present invention relates to the technical field of valve actuators, and more particularly to a double-cylinder three-piston valve pneumatic actuator. Background Art

[0002] Pneumatic actuators are actuators that use air pressure to drive the opening and closing or regulating valves. Pneumatic actuators are mainly composed of components such as cylinders, pistons, gear shafts, end covers, and seals. In the case of driving gate valves or stop valves, the gear shaft is threadedly connected to the valve stem of the valve, and the air source drives the piston to move. The piston drives the valve stem up and down through the rack and gear shaft transmission, thereby achieving the function of regulating or opening and closing the valve. However, there are defects. First, as the size of the valve disc of the stop valve or the gate of the gate valve increases, the distance the valve stem needs to move also increases accordingly, which will increase the length of the rack that drives the gear shaft to rotate, thereby increasing the volume of the pneumatic actuator, requiring a larger installation space, and causing the user's cost to rise; second, one end of the rack is positioned on the piston. As the length of the rack becomes longer, the structural stability of the rack relative to the piston becomes worse, and the rack is prone to bending and deformation, and the degree of meshing with the gear shaft is reduced, resulting in a reduction in the transmission efficiency of the rack and the gear shaft, and even the phenomenon of mutual collapse of the teeth between the rack and the gear shaft. Summary of the invention

[0003] In view of the deficiencies in the prior art, an object of the present invention is to provide a double-cylinder three-piston valve pneumatic actuator which has a compact structure, occupies a small space and has stable transmission.

[0004] To achieve the above-mentioned purpose, the present invention provides the following technical solutions: a double-cylinder three-piston valve pneumatic actuator, comprising a housing, a gear shaft limited in the housing and rotatable relative to the housing, a left piston and a right piston respectively located on both sides of the gear shaft, and a left cover plate and a right cover plate respectively limiting the left piston and the right piston in the housing, the left piston and the right piston are provided with racks meshing with the gear shaft on the facing surfaces, the left cover plate and the right cover plate are both provided with air holes communicating with the interior of the housing, the gear shaft is provided with a movable groove threadedly connected to the valve stem, and the housing is provided with There is a partition chamber for partially accommodating the gear shaft, and an inner piston is arranged in the partition chamber, which is sleeved on the outside of the gear shaft and can only move along the axial direction of the gear shaft. A transverse groove, a thread groove and a transition groove connecting the thread groove and the transverse groove are opened on the outer wall of the gear shaft. The inner piston is provided with a sliding rod with one end inserted into the transverse groove. Two ventilation pipes are respectively arranged on the same side of the left piston and the right piston outside the shell, and the two ventilation pipes connect the inner cavity of the shell with the partition chamber. An upper hole is arranged on the top of the partition chamber to connect the inner cavity of the partition chamber with the outside world. Two top blocks are arranged on the outer wall of the separation chamber, both of which are located in the inner cavity of the shell and connected to the space below the inner piston. A sealing sleeve and a first spring that pushes the sealing sleeve away from the separation chamber are sleeved on the outer side of the two top blocks. A transition chamber sleeved outside the sealing sleeve and used to push the sealing sleeve to move is arranged on the left piston and the right piston, a check chamber that is connected to the transition chamber and is located on the other side of the piston, a check piece that is opposite to the corresponding top block and is used to block the transition chamber and the check chamber, and a second spring that pushes the check piece toward the corresponding top block. An air inlet connected to the inner cavity of the shell is opened on the outer wall of the two check chambers. Hole, the two top blocks are each provided with a transition hole connecting the inner cavity of the transition chamber with the inner cavity of the separation chamber, the two racks are each provided with a groove for the idling of the gear shaft, the left piston and the right piston move toward each other so that the two racks drive the gear shaft to rotate, the slide bar moves along the transverse groove to the transition groove, the gear part of the gear shaft is located between the two grooves, the check piece is pushed by the top block so that the gas passes through the air inlet hole, the check chamber, the transition chamber and the transition hole in turn into the separation chamber and pushes the inner piston to move upward, the slide bar enters the threaded groove and moves along the threaded groove to drive the gear shaft to rotate.

[0005] As a further improvement of the present invention, an anti-rotation sleeve located above the inner piston is arranged in the partition chamber, and an anti-collision rod partially inserted into the anti-rotation sleeve is arranged on the end surface of the inner piston facing the anti-rotation sleeve.

[0006] As a further improvement of the present invention, the surfaces of the two check members used to block the transition chamber from communicating with the check chamber are both conical surfaces.

[0007] As a further improvement of the present invention, a first sealing ring is provided on the inner wall of the inner piston and is in contact with the outer wall of the gear shaft.

[0008] As a further improvement of the present invention, a second sealing ring is provided on the outer wall of the inner piston and is in contact with the inner wall of the partition chamber.

[0009] As a further improvement of the present invention, a bearing is provided in the housing and is located below the gear shaft and through which the valve stem passes.

[0010] As a further improvement of the present invention, a pressure-proof groove for inserting one end of the gear shaft is provided on the end surface of the separation chamber facing the inner piston, and an O-ring is provided on the outer wall of the gear shaft to fit the inner wall of the pressure-proof groove.

[0011] The beneficial effects of the present invention are as follows: the linear movement of the inner piston drives the gear shaft to rotate, causing the valve stem to move up and down. Compared with the prior art, such a design can greatly reduce the length of the rack, making the housing compact and reducing the required installation space, effectively reducing the user's cost and indirectly saving resources; the reduction in the length of the rack can indirectly improve the connection stability between the rack and the corresponding piston and the bending resistance of the rack, thereby ensuring the transmission efficiency of the rack and the gear shaft. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a cross-sectional view of the present invention when the valve is in a closed state;

[0013] Figure 2 It is a cross-sectional view of the present invention when the valve is in an open state;

[0014] Figure 3 for Figure 1 Cross-section at CC;

[0015] Figure 4 for Figure 2 Cross-sectional view at DD in the middle;

[0016] Figure 5 for Figure 1 The enlarged view of point A in the middle;

[0017] Figure 6 for Figure 2 The enlarged view of point B in the middle;

[0018] Figure 7 It is a partial front view of the gear shaft in the present invention;

[0019] Figure 8 It is a schematic diagram of the present invention installed on a valve.

[0020] : Illustration numerals: 1. housing; 11. bearing; 2. gear shaft; 21. movable groove; 22. transverse groove; 23. threaded groove; 24. transition groove; 25. O-ring; 3. left piston; 31. transition chamber; 32. check chamber; 33. check piece; 34. second spring; 35. air inlet; 4. right piston; 5. left cover plate; 51. air hole; 6. right cover plate; 7. rack; 71. groove; 8. partition chamber; 80. upper hole; 81. inner piston; 811. first sealing ring; 812. second sealing ring; 82. sliding rod; 83. top block; 84. sealing sleeve; 85. first spring; 86. transition hole; 87. anti-rotation sleeve; 88. anti-rotation rod; 89. anti-pressure groove; 9. ventilation pipe. DETAILED DESCRIPTION

[0021] The present invention is further described in detail below in conjunction with the accompanying drawings and embodiments, wherein the same components are represented by the same reference numerals.

[0022] Reference Figures 1 to 8 As shown, a double-cylinder three-piston valve pneumatic actuator of this embodiment includes a housing 1, a gear shaft 2 limited in the housing 1 and rotatable relative to the housing 1, a left piston 3 and a right piston 4 respectively located on both sides of the gear shaft 2, a left cover plate 5 and a right cover plate 6 respectively limiting the left piston 3 and the right piston 4 in the housing 1, a rack 7 meshing with the gear shaft 2 is arranged on the facing surfaces of the left piston 3 and the right piston 4, the left cover plate 5 and the right cover plate 6 are both provided with an air hole 51 communicating with the interior of the housing 1, and a moving groove 21 threadedly connected to the valve stem is arranged inside the gear shaft 2;

[0023] Based on the above-mentioned prior art, a transverse groove 22, a threaded groove 23, and a transition groove 24 for connecting the threaded groove 23 and the transverse groove 22 are processed on the outer wall of the gear shaft 2, and a first sealing ring 811 and a second sealing ring 812 are respectively embedded on the inner wall and outer wall of the inner piston 81. Then, the inner piston 81 is sleeved on the outside of the gear shaft 2, and the first sealing ring 811 fits with the outer wall of the gear shaft 2. A threaded hole is opened on the outer wall of the inner piston 81 and a thread matching the threaded hole is partially opened on the slide rod 82. One end of the slide rod 82 is inserted into the threaded hole and a flat-blade screwdriver is used to screw the threaded part of the slide rod 82 into the threaded hole. When the slide rod 82 is rotated into place, one end of the slide rod 82 extends into the transverse groove 22, and the inner piston 81 is installed in the half-open The second sealing ring 812 is fitted with the inner wall of the partition chamber 8, and the interior of the partition chamber 8 is divided into an upper chamber and a lower chamber independent of each other by the inner piston 81. An anti-rotation sleeve 87 and an anti-rotation rod 88 are provided in the upper chamber, and one end of the anti-rotation rod 88 is fixedly connected to the end face of the inner piston 81. A sealing cover is covered at the opening of the partition chamber 8, and the anti-rotation sleeve 87 is positioned on the end face of the sealing cover facing the inner piston 81. An upper hole 80 adjacent to the opening of the partition chamber 8 is provided on the outer wall of the partition chamber 8. The shell 1 is assembled in half from top to bottom, and one end of the assembled partition chamber 8 is passed through the upper half of the shell 1 and the position where the outer wall of the partition chamber 8 contacts the upper half of the shell 1 is welded, and a through hole connected to its inner cavity is provided on the outer wall of the top block 83. A transition hole 86 is provided, and a sealing sleeve 84 and a first spring 85 are sequentially sleeved on the outside of the top block 83. Two through holes are provided on the outer wall of the end of the partition chamber 8 extending into the shell 1. One end of the two top blocks 83 is respectively clamped in the two through holes, so that the inner cavity of the top block 83 is connected with the lower cavity of the partition chamber 8. A groove 71 is provided in the middle of the two racks 7 on the same side as the teeth. A transition chamber 31 and a check chamber 32 are respectively integrally formed on the two end faces of the left piston 3. A through hole connecting the transition chamber 31 and the check chamber 32 is provided on the left piston 3. An air inlet 35 connecting the inner cavity of the check chamber 32 with the outside is provided on the outer wall of the check chamber 32. The second spring 34 is sleeved on the outside of the check piece 33 and one end of the check piece 33 is inserted into a base, and the base is threadedly connected to the check chamber 32 is far away from the opening of the transition chamber 31, the check piece 33 and the second spring 34 are both limited in the check chamber 32, the structure of the right piston 4 is the same as that of the left piston 3, the left piston 3 and the right piston 4 are respectively placed on both sides of the separation chamber 8 and moved toward each other, so that the two transition chambers 31 are sleeved outside the corresponding sealing sleeve 84, the inner wall of the transition chamber 31 is sealed with the outer wall of the sealing sleeve 84, the two racks 7 are moved from bottom to top so that the tooth part of the rack 7 is combined with the gear of the gear shaft 2, one end of the two racks 7 is respectively welded to the end faces facing the left piston 3 and the right piston 4, finally the lower half of the shell 1 is welded to the upper half of the shell 1, the upper hole 80 is located outside the shell 1, the left piston 3, the right piston 4, the gear part of the gear shaft 2 and the two racks 3 are all located in the shell 1,The left piston 3 and the right piston 4 divide the space into an air inlet chamber and an air outlet chamber. The air outlet chamber is adjacent to the partition chamber 8. The left cover plate 5 and the right cover plate 6 are respectively installed at the two ends of the shell 1. The two ends of the two L-shaped ventilation pipes 9 are respectively positioned on the outer walls of the partition chamber 8 and the shell 1 so that the upper chamber of the partition chamber 8 can be connected with the air outlet chamber.

[0024] In the initial state, the left piston 3 and the right piston 4 are in contact with the left cover plate 5 and the right cover plate 6 respectively, the end of the slide rod 82 is located at the end of the transverse groove 22 away from the transition groove 24, the teeth of the two racks 7 are meshed with the gears of the gear shaft 2, the height of the upper end surface of the inner piston 81 is lower than the height of the position where the vent pipe 9 is connected to the partition chamber 8, the transition hole 86 and the transition chamber 31 are blocked by the sealing sleeve 84, the transition chamber 31 and the check chamber 32 are blocked by the check piece 33, one end of the valve stem is screwed into the moving groove 21 of the gear shaft 2, the valve stem cannot rotate relative to the valve body, and the valve is in a closed state; during the valve opening process, the external driving gas enters the air inlet chamber from the air holes 51 on both the left cover plate 5 and the right cover plate 6 at the same time, and the left piston 3 and the right piston 4 The valve stem 82 moves in a vertical direction and moves a short distance relative to the gear shaft 2. The valve stem 82 is initially opened until the gear part of the gear shaft 2 is disengaged from the tooth part of the two racks 7 and enters the groove 71. The sliding rod 82 moves along the transverse groove 22 to the transition groove 24. As the check member 33 is pushed by the top block 83 and moves relative to the base, the second The spring 34 is compressed, the transition chamber 31 is connected with the check chamber 32, and the gas in the air inlet chamber enters the lower chamber through the air hole 35, the check chamber 32, the transition chamber 31, and the transition hole 86 in turn. The inner piston 81 is pushed upward, and the slide rod 82 enters the thread groove 23 and slides relative to the thread groove 23. The gear shaft 2 continues to rotate relative to the inner piston 81 so that the valve stem continues to move into the movable groove 21, and the anti-rotation rod 88 gradually extends into the anti-rotation sleeve 87 until the valve is opened to the maximum flow rate, the valve stem stops moving, the inner piston 81 stops moving, the connection between the vent pipe 9 and the upper chamber is blocked by the inner piston 81, and the left piston 3 and the right piston 4 stop moving; during the valve closing process, the external driving gas enters the upper chamber from the upper hole 80, and the inner piston 81 moves downward The slide bar 82 moves along the thread groove 23 and causes the gear shaft 2 to rotate in the opposite direction. The valve stem gradually moves out of the moving groove 21. The flow rate inside the valve decreases rapidly until the slide bar 82 returns to the transition groove 23 and stops moving. The upper chamber is connected to the air outlet chamber again, and the gas enters the air outlet chamber through the vent pipe 9. The left piston 3 and the right piston 4 move away from each other. The second spring 34 and the first spring 85 restore their deformations successively. The sealing sleeve 84 and the check piece 33 are both reset. The check piece 33 is separated from the top block 83, the transition chamber 31 is disconnected from the check chamber 32, and the transition chamber 31 is disconnected from the transition hole 86. The two racks 7 are meshed with the gear shaft 2 again and drive the gear shaft 2 to rotate. The slide bar 82 moves to the initial position along the transverse groove 22, and the valve is completely closed.

[0025] Compared with the prior art, such a design can greatly reduce the length of the rack 7, making the housing 1 compact and reducing the required installation space, effectively reducing the user's cost and indirectly saving resources; the reduced length of the rack 7 can indirectly improve the connection stability between the rack 7 and the corresponding piston and the bending resistance of the rack 7, thereby ensuring the transmission efficiency of the rack 7 and the gear shaft 2.

[0026] As a specific implementation method of the improvement, refer to Figure 5 and Figure 6 As shown, the through hole between the check chamber 32 and the transition chamber 31 is a circular hole, and the two check pieces 33 are partially designed to be conical surfaces with the small ends facing the circular holes. When the check pieces 33 block the connection between the transition chamber 31 and the check chamber 32, the conical surfaces touch the open ends of the circular holes. Such a design can ensure that the position of the check piece 33 is adjusted so that the check piece 33 is coaxial with the top block 83 and touches effectively, and at the same time, the sealing effect formed by the conical surface and the circular hole is good.

[0027] As a specific implementation method of the improvement, refer to Figure 1 and Figure 2 As shown, the housing 1 is detachably connected to a bottom cover, which is located directly below the gear shaft 2. A bearing 11 is coaxially connected to the end face of the bottom cover facing the gear shaft 2. The bottom cover is connected to the housing 1, and the bearing 11 is located between the gear shaft 2 and the bottom cover. During the process of connecting the valve stem to the gear shaft 2, the valve stem passes through the bottom cover and the bearing 11 in turn. The design of the bearing 11 is conducive to calibrating the coaxiality of the valve stem and the gear shaft 2, making it easier for the valve stem to be screwed into the gear shaft 2, and at the same time can improve the smoothness of the valve stem rotation.

[0028] As an improved specific implementation method, an anti-pressure groove 89 matching the diameter of the end of the gear shaft 2 is opened on the cover of the partition chamber 8, and an O-ring 25 is sleeved on the outer wall of the gear shaft 2. When the cover is closed on the port of the partition chamber 8, the end of the gear shaft 2 extends into the anti-pressure groove 89, and the O-ring 25 fits with the inner wall of the anti-pressure groove 89 to form a seal. Compared with the design in which the end of the gear shaft 2 is located in the upper cavity of the partition chamber 8, such a design can avoid the gas entering the upper cavity and applying downward pressure on the end face of the gear shaft 2, thereby causing difficulty in rotating the gear shaft 2. The O-ring 25 can avoid the gas entering the anti-pressure groove 89 and applying downward force on the gear shaft 2, thereby ensuring the smoothness of the rotation of the gear shaft 2.

[0029] The above is only a preferred embodiment of the present invention, and the protection scope of the present invention is not limited to the above embodiments. All technical solutions under the concept of the present invention belong to the protection scope of the present invention. It should be pointed out that for ordinary technicians in this technical field, some improvements and modifications without departing from the principle of the present invention should also be regarded as the protection scope of the present invention.

Claims

1. A double-cylinder three-piston valve pneumatic actuator, comprising a housing (1), a gear shaft (2) limited in the housing (1) and rotatable relative to the housing (1), a left piston (3) and a right piston (4) respectively located on both sides of the gear shaft (2), a left cover plate (5) and a right cover plate (6) respectively limiting the left piston (3) and the right piston (4) in the housing (1), the left piston (3) and the right piston (4) are provided with a rack (7) meshing with the gear shaft (2) on the facing surfaces of the left piston (3) and the right piston (4), the left cover plate (5) and the right cover plate (6) are both provided with an air hole (51) communicating with the interior of the housing (1), the gear shaft (2) is provided with a moving groove (21) threadedly connected to the valve stem, and is characterized in that: The housing (1) is provided with a partition chamber (8) for partially accommodating the gear shaft (2); an inner piston (81) is provided in the partition chamber (8) and is sleeved outside the gear shaft (2) and can only move along the axial direction of the gear shaft (2); a transverse groove (22), a thread groove (23) and a transition groove (24) connecting the thread groove (23) and the transverse groove (22) are provided on the outer wall of the gear shaft (2); the inner piston (81) is provided with a slide rod (82) with one end inserted into the transverse groove (22); and two ventilation pipes (9) are connected to the outside of the housing (1) and are respectively provided on the same side as the left piston (3) and the right piston (4). The two ventilation pipes (9) both connect the inner cavity of the shell (1) and the partition chamber (8); the top of the partition chamber (8) is provided with an upper hole (80) for connecting the inner cavity of the partition chamber (8) with the outside; the outer wall of the partition chamber (8) is provided with two top blocks (83) both located in the inner cavity of the shell (1) and connected with the space below the inner piston (81); the two top blocks (83) are both sleeved with a sealing sleeve (84) and a first spring (85) for pushing the sealing sleeve (84) away from the partition chamber (8); the left piston (3) and the right piston (4) are both provided with a transition spring sleeve (84) sleeved outside the sealing sleeve (84) and used to push the sealing sleeve (84) to move. The invention relates to a first piston housing (31), a first piston housing (32) connected to the transition chamber (31), a second ... 1), the left piston (3) and the right piston (4) move toward each other so that the two racks (7) drive the gear shaft (2) to rotate, the slide bar (82) moves along the transverse groove (22) to the transition groove (24), the gear part of the gear shaft (2) is located between the two grooves (71), the check piece (33) is pushed by the top block (83) so that the gas enters the partition chamber (8) through the air inlet hole (35), the check chamber (32), the transition chamber (31) and the transition hole (86) in sequence and pushes the inner piston (81) to move upward, the slide bar (82) enters the thread groove (23) and moves along the thread groove (23) to drive the gear shaft (2) to rotate.

2. A double-cylinder three-piston valve pneumatic actuator according to claim 1, characterized in that: An anti-rotation sleeve (87) located above the inner piston (81) is arranged in the partition chamber (8), and an anti-collision rod (88) partially inserted into the anti-rotation sleeve (87) is arranged on the end surface of the inner piston (81) facing the anti-rotation sleeve (87).

3. A double-cylinder three-piston valve pneumatic actuator according to claim 1 or 2, characterized in that: The surfaces of the two non-return parts (33) used to block the transition chamber (31) from communicating with the non-return chamber (32) are both conical surfaces.

4. A double-cylinder three-piston valve pneumatic actuator according to claim 1 or 2, characterized in that: A first sealing ring (811) is provided on the inner wall of the inner piston (81) and is in contact with the outer wall of the gear shaft (2).

5. A double-cylinder three-piston valve pneumatic actuator according to claim 1 or 2, characterized in that: A second sealing ring (812) is provided on the outer wall of the inner piston (81) and is in contact with the inner wall of the partition chamber (8).

6. A double-cylinder three-piston valve pneumatic actuator according to claim 1 or 2, characterized in that: A bearing (11) is arranged in the housing (1) and is located below the gear shaft (2) and is passed through by the valve stem.

7. A double-cylinder three-piston valve pneumatic actuator according to claim 1 or 2, characterized in that: An anti-pressure groove (89) for inserting one end of the gear shaft (2) is provided on the end surface of the partition chamber (8) facing the inner piston (81), and an O-ring (25) is provided on the outer wall of the gear shaft (2) to fit the inner wall of the anti-pressure groove (89).

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