Air floatation cylinder capable of adjusting push-pull force

Abstract

The invention belongs to the field of air floatation cylinders, and discloses an air floatation cylinder with adjustable push-pull force, which comprises a cylinder barrel, a piston rod, an upper air floatation piston, a lower air floatation piston and an air floatation bearing, the cylinder barrel is provided with an upper air cavity and a lower air cavity, the piston rod is arranged in the cylinder barrel in a vertical sliding manner, the upper air floatation piston is arranged on the piston rod and is positioned in the upper air cavity, and the lower air floatation piston is positioned in the lower air cavity. The upper air floating piston is not connected with the inner wall of the upper air cavity, upper piston holes are annularly distributed in the side wall of the upper air floating piston, the lower air floating piston is arranged on the piston rod and located in the lower air cavity, the lower air floating piston is not connected with the inner wall of the lower air cavity, lower piston holes are annularly distributed in the side wall of the lower air floating piston, and the air floating bearing is arranged at the lower end of the air cylinder barrel. According to the piston, the tension of the piston is jointly changed through air pressure change and effective area change, the tension adjustable range is increased under the condition that the air cylinder is not disassembled and assembled, and the use range of the air cylinder is increased.

Description

Technical Field

[0001] The invention relates to the field of air floating cylinders, in particular to an air floating cylinder with adjustable push and pull forces. Background Art

[0002] Ordinary cylinders usually use contact seals, which have greater friction resistance when the piston moves. Using an air-floating cylinder can not only reduce the friction during piston movement, but also allow the cylinder piston to move at a greater speed.

[0003] The traditional air-floating cylinder solution uses a set of air-floating pistons and air-floating bearings. There is a high-pressure area in the cylinder, and the rest is a normal-pressure area. The cylinder applies a push-pull force to the cylinder shaft through the pressure difference on both sides of the air-floating piston, and then the cylinder shaft outputs the push-pull force to other equipment. The push-pull force of the cylinder depends on the contact area between the air-floating piston and the high-pressure area and the air pressure in the high-pressure area. Usually, the contact area between the air-floating piston and the high-pressure area is determined by the size of the cylinder and cannot be changed during use. Therefore, the push-pull force of a conventional cylinder can only be determined by the pressure difference between the high-pressure and low-pressure areas.

[0004] However, the air pressure in the high-pressure area has a relatively small adjustment range. The lowest air pressure in the high-pressure area cannot be lower than the minimum pressure required to maintain the air film formed by the air-floating piston. When the pressure in the high-pressure area of ​​the cylinder is lower than the minimum value, the working pressure of the air-floating piston and the air-floating bearing is reduced, and the thickness of the air film formed becomes thinner or even fails to form. When subjected to lateral force or torque, the air-floating piston and the cylinder wall, the air-floating bearing and the cylinder shaft will generate contact friction, causing the friction of the cylinder to increase rapidly, and even causing structural damage to the cylinder.

[0005] The maximum air pressure in the high-pressure area shall not be higher than the maximum pressure that the cylinder components can withstand. When the pressure in the high-pressure area of ​​the cylinder is higher than the maximum value, the air pressure in the cylinder exceeds the normal working pressure of the cylinder components, causing obvious deformation of the cylinder components and damaging the cylinder structure. At the same time, the air pressure difference on both sides of the piston surface is too high, and the gas leakage through the piston surface increases greatly, affecting the effect of the air flotation film and causing an increase in the amount of gas leakage.

[0006] Therefore, adjusting the cylinder push-pull force only by adjusting the cylinder pressure not only allows a small adjustment range, but also creates risks to equipment safety and reliability when the air pressure approaches the critical point.

[0007] In order to meet the needs of different pulling forces, the current cylinder technology requires that if the air pressure range allowed by a single cylinder is exceeded, a cylinder with a different pulling force range must be replaced. During the replacement process, the equipment often needs to be disassembled and reassembled, which is complicated and time-consuming, and the equipment is easily damaged during repeated disassembly and assembly. Summary of the invention

[0008] The object of the present invention is to provide an air-floating cylinder with adjustable push-pull force to solve the problems raised in the above-mentioned background technology.

[0009] To achieve the above object, the present invention provides the following technical solutions:

[0010] An air-floating cylinder with adjustable push-pull force, comprising:

[0011] A cylinder barrel, the cylinder barrel having an upper air chamber and a lower air chamber, wherein the cross-sectional areas of the upper air chamber and the lower air chamber are unequal;

[0012] An air bearing, wherein the air bearing is arranged at the lower end of the cylinder barrel;

[0013] A piston rod, the piston rod is located in the cylinder barrel and is in air-floating sliding cooperation with the air-floating bearing up and down;

[0014] An upper air-floating piston, which is arranged on the piston rod and located in the upper air cavity. The upper air-floating piston is not connected to the inner wall of the upper air cavity. The side wall of the upper air-floating piston is surrounded by piston holes. The upper air-floating piston blows air toward the inner wall of the upper air cavity through the upper piston holes, so that the outer wall of the upper air-floating piston and the inner wall of the upper air cavity are air-floatingly slidably matched up and down; and

[0015] The lower air floating piston is arranged on the piston rod and is located in the lower air cavity. The lower air floating piston is not connected to the inner wall of the lower air cavity. The side wall of the lower air floating piston is surrounded by the lower piston hole. The lower air floating piston blows air toward the inner wall of the lower air cavity through the lower piston hole, so that the outer wall of the lower air floating piston and the inner wall of the lower air cavity are air-floated and slidably matched.

[0016] Furthermore, the cross-sectional area of ​​the upper air cavity is larger than the cross-sectional area of ​​the lower air cavity, and the cross-sectional area of ​​the upper air-floating piston is larger than the cross-sectional area of ​​the lower air-floating piston.

[0017] Furthermore, the upper air-floating piston has an upper piston inner cavity communicated with the upper piston hole, and the lower air-floating piston has a lower piston inner cavity communicated with the lower piston hole.

[0018] Furthermore, a high-pressure gas circuit is arranged on the piston rod, and the high-pressure gas circuit is used to supply gas to the inner cavity of the upper piston and the inner cavity of the lower piston.

[0019] Furthermore, the upper air-floating piston divides the upper air chamber into a first air chamber and a second air chamber, the first air chamber is connected to the atmosphere or a normal pressure air source, the lower piston divides the lower air chamber into a third air chamber and a fourth air chamber, the third air chamber is connected to the second air chamber, a first air supply connector is arranged on the second air chamber and / or the third air chamber, and a second air supply connector is arranged on the fourth air chamber; the high-pressure air circuit is respectively connected to the upper piston inner cavity and the lower piston inner cavity, the high-pressure air circuit is connected to the fourth air chamber, and the high-pressure air circuit is also connected to the second air chamber and / or the third air chamber.

[0020] Furthermore, a first one-way valve and a second one-way valve are arranged on the high-pressure air circuit, the first one-way valve allows air flow to enter the high-pressure air circuit from the second air cavity and / or the third air cavity, but does not allow air flow to enter the second air cavity and / or the third air cavity from the high-pressure air circuit, and the second one-way valve allows air flow to enter the high-pressure air circuit from the fourth air cavity, but does not allow air flow to enter the fourth air cavity from the high-pressure air circuit.

[0021] Furthermore, an upper piston pressure relief groove is arranged on the outer wall of the upper air floating piston, an upper piston pressure relief hole communicating with the upper piston pressure relief groove is arranged on the upper air floating piston, and the upper piston pressure relief hole is communicated with the first air cavity.

[0022] Furthermore, a lower piston pressure relief groove is arranged on the outer wall of the lower air-floating piston, a lower piston pressure relief hole connected with the lower piston pressure relief groove is arranged on the lower air-floating piston, the lower piston pressure relief hole is connected to the inner wall of the lower air-floating piston, and a normal-pressure air path is arranged on the piston rod, and the normal-pressure air path is respectively connected with the lower piston pressure relief hole and the atmosphere.

[0023] Furthermore, it also includes an air supply system, which supplies air to the fourth air cavity, and the air supply system also supplies air to the second air cavity and / or the third air cavity, and includes a high-pressure air source, a high-pressure pressure-stabilizing tank, an air filter, a pressure-reducing valve, a first three-way valve, a second three-way valve, a first air pressure sensor, and a second air pressure sensor; the high-pressure air source, the high-pressure pressure-stabilizing tank, the air filter, and the pressure-reducing valve are connected in sequence through pipelines, and the pressure-reducing valve is connected to the first three-way valve and the second three-way valve through pipelines, respectively, and the first three-way valve is connected to the second air cavity and / or the third air cavity through a pipeline, and the first air pressure sensor is used to detect the air pressure input to the second air cavity and / or the third air cavity, the second three-way valve is connected to the fourth air cavity through a pipeline, and the second air pressure sensor is used to detect the air pressure input to the fourth air cavity.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] 1) The piston changes the piston tension through changes in air pressure and effective area, which increases the adjustable range of tension without disassembling the cylinder and increases the application range of the cylinder.

[0026] 2) When using an air-floating cylinder, the piston does not contact the outer wall of the cylinder when the piston rod moves axially and circumferentially, and there is no friction resistance;

[0027] 3) During the movement of the piston rod, there is no air pipeline connected to the piston rod, so no additional pulling force will be generated, making the piston output pulling force more accurate and not affected by movement;

[0028] 4) The air-floating design of the upper and lower pistons is used to solve the lateral force and torque of the piston rod. When the lateral force and torque are increased, the friction force will not be increased, and the piston rod is still in a state of free movement in the axial and circumferential directions;

[0029] 5) An air film is formed between the upper and lower pistons and the cylinder wall, so the gap between the piston and the cylinder wall is small, reducing the amount of cylinder leakage. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a partial structural schematic diagram of the present invention.

[0031] Figure 2 It is a schematic diagram of partial structural decomposition of the present invention.

[0032] Figure 3 It is a schematic cross-sectional view of part of the structure of the present invention.

[0033] Figure 4 It is a schematic diagram of the cross-sectional structure of the upper air-floating piston in the present invention.

[0034] Figure 5 It is a schematic diagram of the cross-sectional structure of the lower air-floating piston in the present invention.

[0035] Figure 6 It is a partial structural schematic diagram of the gas supply system in the present invention.

[0036] In the figure:

[0037] Upper air-floating piston 1, upper piston hole 101, upper piston inner cavity 102, upper piston pressure relief groove 103, upper piston pressure relief channel 104;

[0038] The lower air floating piston 2, the lower piston hole 201, the lower piston inner cavity 202, the lower piston pressure relief groove 203, and the lower piston pressure relief channel 204;

[0039] Piston rod 3, upper piston air supply channel 301, first one-way valve 302, lower piston air supply channel 303, second one-way valve 304, high-pressure air circuit 305, normal-pressure air circuit 306;

[0040] Limiting ring 4;

[0041] A first air supply connector 501, a second air supply connector 502, a high-pressure air source 503, a high-pressure stabilizing tank 504, an air filter 505, a pressure reducing valve 506, atmosphere 507, a first three-way valve 508, a second three-way valve 509, a first air pressure sensor 510, and a second air pressure sensor 511;

[0042] Cylinder barrel 6, first air cavity 601, second air cavity 602, third air cavity 603, fourth air cavity 604;

[0043] Air bearing 7. DETAILED DESCRIPTION

[0044] 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.

[0045] See also Figure 1-Figure 6 , an air-floating cylinder with adjustable push-pull force, comprising a cylinder barrel 6, a piston rod 3, an upper air-floating piston 1, a lower air-floating piston 2, a limit ring 4 and an air-floating bearing 7, the cylinder barrel 6 has an upper air cavity and a lower air cavity, the cross-sectional areas of the upper air cavity and the lower air cavity are not equal, and the cross-sectional areas of the upper air cavity are uniform, and the cross-sectional areas of the lower air cavity are uniform, the air-floating bearing 7 is arranged at the lower end of the cylinder barrel 6, the piston rod 3 is located in the cylinder barrel 6 and is in upper and lower air-floating sliding cooperation with the air-floating bearing 7, the upper air-floating piston 1 is arranged on the piston rod 3 and is located in the upper air cavity, the upper air-floating piston 1 is not connected to the inner wall of the upper air cavity, and the upper air-floating piston 1 is surrounded by upper piston holes 101 on the side wall, and the upper air-floating piston 1 blows air toward the inner wall of the upper air cavity through the upper piston hole 101, so that the outer wall of the upper air-floating piston 1 and the inner wall of the upper air cavity are air-floated and slidably matched up and down, and the lower air-floating piston 2 is arranged on the piston rod 3 and is located in the lower air cavity. The lower air-floating piston 2 is not connected to the inner wall of the lower air cavity, and the side wall of the lower air-floating piston 2 is surrounded by lower piston holes 201, and the lower air-floating piston 2 blows air toward the inner wall of the lower air cavity through the lower piston hole 201, so that the outer wall of the lower air-floating piston 2 and the inner wall of the lower air cavity are air-floated and slidably matched up and down, and the limit retaining ring 4 is arranged at the upper end of the cylinder barrel 6.

[0046] Continue reading Figure 3 In one embodiment of the present invention, the cross-sectional area of ​​the upper air chamber is greater than that of the lower air chamber, and the cross-sectional area of ​​the upper air-floating piston 1 is greater than that of the lower air-floating piston 2. The upper air-floating piston 1 divides the upper air chamber into a first air chamber 601 and a second air chamber 602 from top to bottom. The first air chamber 601 is connected to the atmosphere or a normal pressure air source, and a first air supply connector 501 is provided on the second air chamber 602. The lower air-floating piston 2 divides the lower air chamber into a third air chamber 603 and a fourth air chamber 604 from top to bottom. The third air chamber 603 is connected to the second air chamber 602, and a second air supply connector 502 is provided on the fourth air chamber 604.

[0047] Continue reading Figure 3 In one embodiment of the present invention, the upper air-floating piston 1 has an upper piston inner cavity 102 communicating with the upper piston hole 101 , and the lower air-floating piston 2 has a lower piston inner cavity 202 communicating with the lower piston hole 201 .

[0048] Continue reading Figure 3In one embodiment of the present invention, a high-pressure gas circuit 305 is provided on the piston rod 3, and the high-pressure gas circuit 305 is used to supply gas to the upper piston inner cavity 102 and the lower piston inner cavity 202. The high-pressure gas circuit 305 is connected to the upper piston inner cavity 102 through the upper piston air supply channel 301, and the high-pressure gas circuit 305 is connected to the lower piston inner cavity 202 through the lower piston air supply channel 303. The high-pressure gas circuit 305 is connected to the second air cavity 602 through the first one-way valve 302, and the high-pressure gas circuit 305 is also connected to the fourth air cavity 604 through the second one-way valve 304. The first one-way valve 302 allows airflow from the second air cavity 602 to enter the high-pressure gas circuit 305, and does not allow airflow from the high-pressure gas circuit 305 to enter the second air cavity 602. The second one-way valve 304 allows airflow from the fourth air cavity 604 to enter the high-pressure gas circuit 305, and does not allow airflow from the high-pressure gas circuit 305 to enter the fourth air cavity 604.

[0049] Continue reading Figure 3-Figure 5 In one embodiment of the present invention, two annular upper piston pressure relief grooves 103 are arranged on the upper and lower outer walls of the upper air-floating piston 1, the upper piston hole 101 is arranged in the area between the upper and lower upper piston pressure relief grooves 103, and a plurality of upper piston pressure relief channels 104 connected to the upper and lower upper piston pressure relief grooves 103 are evenly distributed on the upper air-floating piston 1, and the upper ends of the upper piston pressure relief channels 104 are connected to the first air chamber 601.

[0050] Continue reading Figure 3-Figure 5 In one embodiment of the present invention, two lower piston pressure relief grooves 203 are arranged on the upper and lower outer walls of the lower air-floating piston 2, the lower piston hole 201 is arranged in the area between the upper and lower lower piston pressure relief grooves 203, a plurality of lower piston pressure relief holes 204 connected to the upper and lower lower piston pressure relief grooves 203 are evenly distributed on the lower air-floating piston 2, the lower piston pressure relief holes 204 are connected to the inner wall of the lower air-floating piston 2, a normal pressure gas path 306 is arranged on the piston rod 3, the upper end of the normal pressure gas path 306 is connected to the lower piston pressure relief hole 204, and the lower end is connected to the atmosphere.

[0051] Continue reading Figure 3 and Figure 6In one embodiment of the present invention, it also includes an air supply system, which supplies air to the second air cavity 602 and the fourth air cavity 604 respectively, and includes a high-pressure air source 503, a high-pressure pressure regulating tank 504, an air filter 505, a pressure reducing valve 506, a first three-way valve 508, a second three-way valve 509, a first air pressure sensor 510, a second air pressure sensor 511, a first air supply connector 501, and a second air supply connector 502. The high-pressure gas source 503, the high-pressure stabilizing tank 504, the air filter 505, and the pressure reducing valve 506 are connected in sequence through pipelines. The pressure reducing valve 506 is connected to the first three-way valve 508 and the second three-way valve 509 through pipelines respectively. The first three-way valve 508 is connected to the first gas supply connector 501 through a pipeline. The first gas supply connector 501 is arranged on the second gas cavity 602. The first air pressure sensor 510 is arranged on the pipeline between the first three-way valve 508 and the first gas supply connector 501, which is used to detect the air pressure input into the second gas cavity 602. The second three-way valve 509 is connected to the second gas supply connector 502 through a pipeline. The second gas supply connector 502 is arranged on the fourth gas cavity 604. The second air pressure sensor 511 is arranged on the pipeline between the second three-way valve 509 and the second gas supply connector 502, which is used to detect the air pressure input into the fourth gas cavity 604. Among them, the first three-way valve 508 and the second three-way valve 509 both have a port connected to the atmosphere.

[0052] Further explanation of the cylinder barrel 6: The overall structure of the cylinder barrel 6 is a double-ring cylindrical structure with different upper and lower cross-sectional areas, and the cross-sectional area of ​​the upper cylinder is larger than that of the lower end. When the air pressure adjustment range of the air supply system is 1 to N times the lowest air pressure, the cross-sectional area of ​​the upper end is (N+1) times the cross-sectional area of ​​the lower end. For example, if the allowable adjustment range of the cylinder air pressure is 15kPa to 45kPa, the air pressure adjustment range is 1-3 times the lowest air pressure, N=3, then the cross-sectional area of ​​the upper end is 4 times the cross-sectional area of ​​the lower end. There is an air hole on the side of the upper and lower parts of the cylinder barrel 6, which is connected to the air supply connector of the air supply system. The upper and lower ends of the cylinder barrel 6 are open, the upper end is connected to the limit retaining ring 4, and the lower end is non-contact dynamic sealing of the piston rod 3 and the cylinder barrel 6 by the air bearing 7.

[0053] Further explanation of the upper air-floating piston 1: The smooth round surface of the upper air-floating piston 1 is provided with micropores, and an air-floating surface is formed when the air supply system is ventilated. The air-floating surface prevents the upper air-floating piston 1 from having direct contact with the cylinder wall, ensuring that the upper air-floating piston 1 is not affected by frictional resistance during movement. The upper air-floating piston 1 is in the shape of a hollow cylinder as a whole, and the diameter of the cylinder is 20nm smaller than the diameter of the inner side of the upper end section of the cylinder barrel 6, which is the width required to form an air-floating air film. The internal hollow part is the upper piston cavity 102, and the upper piston cavity 102 provides high-pressure gas for the upper piston hole 101 on the side of the upper air-floating piston 1, ensuring that an air-floating surface can be formed on the side of the upper air-floating piston 1. The center of the upper air-floating piston 1 is fixed to the piston rod 3 by threads, and during movement, the piston rod 3 moves with the upper air-floating piston 1 and the lower air-floating piston 2. An upper piston air supply channel 301 is designed in the piston rod 3, and the high-pressure gas enters the upper piston inner cavity 102 of the upper air-floating piston 1 through the upper piston air supply channel 301. The upper air-floating piston 1 separates the cylinder area. Above the upper air-floating piston 1 is the first air chamber 601, which is connected to the atmosphere and is always at normal pressure. The second air chamber 602 and the third air chamber 603 below the upper air-floating piston 1 are interconnected, and the air pressure is controlled by the air supply system. They are connected through the first air supply connector 501 of the air supply system, and can switch between high-pressure and normal-pressure states under different working conditions. The upper air-floating piston 1 includes two upper piston pressure relief grooves 103 and an upper piston pressure relief channel 104. When the cylinder is running, the air-floating surface of the upper air-floating piston 1 works, and the gas discharged from the air-floating surface flows into the ambient atmosphere through the upper piston pressure relief groove 103 and the upper piston pressure relief channel 104.

[0054] Further explanation of the lower air-floating piston 2: The side of the lower air-floating piston 2 is a smooth round surface with micropores thereon, which forms an air-floating surface under high-pressure ventilation. The air-floating surface prevents the lower air-floating piston 2 from directly contacting the cylinder wall, ensuring that the lower air-floating piston 2 is not affected by frictional resistance during movement. The lower air-floating piston 2 is in the shape of a hollow cylinder as a whole, and the diameter of the cylinder is 20nm smaller than the diameter of the inner side of the lower end cross section of the cylinder barrel 6, which is the width required to form an air-floating air film. The internal hollow part is the lower piston cavity 202 of the lower air-floating piston 2, and the lower piston cavity 202 provides high-pressure gas for the lower piston hole 201 on the side of the lower air-floating piston 2, ensuring that the side of the lower air-floating piston 2 can form an air-floating surface. The center of the lower air-floating piston 2 is fixed to the piston rod 3 by threads, and during movement, the piston rod 3 moves with the upper air-floating piston 1 and the lower air-floating piston 2. The piston rod 3 is designed with a piston rod lower piston air supply channel 303, and the high-pressure gas enters the lower piston inner cavity 202 of the lower air-floating piston 2 through the lower piston air supply channel 303. The lower air-floating piston 2 is designed with two upper and lower lower piston air release grooves 203 on the side, which are used to discharge the gas generated by the air-floating surface to ensure the stable formation of the air-floating surface. The lower air-floating piston 2 separates the cylinder area. Above the lower air-floating piston 2 are the second air chamber 602 and the third air chamber 603, the air pressure of which is controlled by the air supply system, connected through the first air supply connector 501 of the air supply system, and can be switched between high-pressure and normal-pressure states under different working conditions. The fourth air chamber 604 below the lower air-floating piston is controlled by the air supply system, connected through the second air supply connector 502 of the air supply system, and can be switched between high-pressure and normal-pressure states under different working conditions.

[0055] The limit ring 4 is further explained as follows: the limit ring 4 is in the shape of a flat ring and is installed at the top of the cylinder barrel 6 to play a limiting role to prevent the cylinder piston from leaving the movement range when the cylinder is normally used.

[0056] Further explanation of the air bearing 7: the air bearing 7 is installed at the bottom end of the cylinder 6. The piston rod 3 needs to pass through the high-pressure area of ​​the cylinder and the normal-pressure area of ​​the outside, and the piston rod 3 moves axially during the piston movement. The air bearing 7 plays a dynamic sealing role for the fourth air chamber 604, preventing the high-pressure gas in the fourth air chamber 604 from leaking into the ambient atmosphere, while allowing the piston rod 3 to move in an axial linear motion and a circumferential rotational motion.

[0057] Further explanation of the piston rod 3: the piston rod 3 is used to fix the upper air-floating piston 1 and the lower air-floating piston 2, and transmit the cylinder push-pull force to the external function that needs to be connected. At the same time, the internal air path of the piston rod 3 provides high-pressure gas for the air-floating function of the upper air-floating piston 1 and the lower air-floating piston 2. The piston rod 3 is a slender rod-shaped structure with holes dug inside to form two air paths, namely the high-pressure air path 305 and the normal-pressure air path 306. The first one-way valve 302 and the second one-way valve 304 are respectively designed in the air inlet of the high-pressure air path 305 leading to the second air cavity 602 and the fourth air cavity 604. The first one-way valve 302 and the second one-way valve 304 only allow gas to enter the internal air path of the piston rod 3 from the second air cavity 602 or the fourth air cavity 604 in one direction. When the piston is in use, at least one of the second air cavity 602 and the fourth air cavity 604 must be in a high-pressure state. In any case, high-pressure gas can enter the piston rod 3 through the one-way valve, and due to the effect of the one-way valve, the high-pressure gas in the high-pressure gas circuit 305 will not leak into the normal pressure area. After the high-pressure gas enters the one-way valve, it is connected to the upper air-floating piston 1 and the lower air-floating piston 2, and is used by the air-floating piston to form an air-floating surface. The normal-pressure gas circuit 306 of the piston rod 3 is connected to the lower piston pressure relief channel 204 of the lower air-floating piston 2, and is connected to the two lower piston pressure relief grooves 203 of the lower air-floating piston 2. When the cylinder is running, the air-floating surface of the lower air-floating piston 2 works, and the gas discharged from the air-floating surface passes through the lower piston pressure relief groove 203, the lower piston pressure relief channel 204, and the normal-pressure gas circuit 306 of the piston rod 3, and finally flows into the ambient atmosphere. The use of the lower piston pressure relief groove 203 ensures the stable formation of the air-floating surface of the lower air-floating piston 2.

[0058] Further explanation of the gas supply system: When the high-pressure gas source 503 is enabled, the high-pressure stabilizer tank 504 is inflated. When high-pressure gas is needed, the pressure reducing valve 506 is opened, and the compressed air in the high-pressure stabilizer tank 504 is filtered by the air filter 505 and then reduced to the required pressure through the pressure reducing valve 506 for use in subsequent pipelines.

[0059] The air supply system can adjust the pressure states of the second air cavity 602, the third air cavity 603, and the fourth air cavity 604, so that the cylinder is in the following four different working modes:

[0060] Working mode 1: When the cylinder is in the deactivated state, the first three-way valve 508 connects the second air cavity 602 to the ambient atmosphere, and the second three-way valve 509 connects the fourth air cavity 4 to the ambient atmosphere. At this time, the first air cavity 601, the second air cavity 602, the third air cavity 603, and the fourth air cavity 604 are all connected to the atmosphere and are in a normal pressure state.

[0061] Working mode two: when the cylinder is in a low tension state, the first three-way valve 508 connects the ambient atmosphere with the second air cavity 602, and the second three-way valve 508 connects the high-pressure gas passing through the pressure reducing valve 506 with the fourth air cavity 604. At this time, the first air cavity 601, the second air cavity 602, and the third air cavity 603 are connected to the atmosphere and are in a normal pressure state, and the fourth air cavity 604 is in a high-pressure state.

[0062] Working mode three: when the cylinder is in a medium tension state, the first three-way valve 508 connects the high-pressure gas passing through the pressure reducing valve 506 with the second air cavity 602, and the second three-way valve 509 connects the ambient atmosphere with the fourth air cavity 604. At this time, the first air cavity 601 and the fourth air cavity 604 are connected to the atmosphere and are in a normal pressure state, and the second air cavity 602 and the third air cavity 603 are in a high-pressure state.

[0063] Working mode four: when the cylinder is in a high tension state, the first three-way valve 508 connects the high-pressure gas passing through the pressure reducing valve 506 with the second air cavity 602, and the second three-way valve 509 connects the high-pressure gas passing through the pressure reducing valve 506 with the fourth air cavity 604. At this time, the first air cavity 601 is connected to the atmosphere and is in a normal pressure state, and the second air cavity 602, the third air cavity 603, and the fourth air cavity 604 are in a high-pressure state.

[0064] The axial tension of the cylinder is determined by the cross-sectional area of ​​the cylinder and the pressure difference at both ends of the piston, specifically F=P·S. The present invention improves the structure of the cylinder barrel, and uses two pistons to change the effective piston area in actual use. The upper air-floating piston 1 and the lower air-floating piston 2 are installed in the cylinder to separate different areas of the cylinder, including changes in the cross-sections of the upper and lower ends of the cylinder, and the gas in the cylinder is divided into four areas: the first air chamber 601, the second air chamber 602, the third air chamber 603, and the fourth air chamber 604. By changing the connection method of the gas in the four areas, the air pressure of the area is changed to achieve different cylinder tensions. Among them, the first air chamber 601 is at the top of the cylinder, directly connected to the ambient atmosphere, and is always a normal pressure area. The second air chamber 602 is directly connected to the third air chamber 3, and the air pressure of the two areas is always kept the same. It is connected to the first air supply connector 501 of the air supply system, and the air is supplied by the air supply system, which can be adjusted to a high pressure state or a normal pressure state. The fourth air chamber 604 is sealed by the lower air floating piston 2 and the air floating bearing 7, and is connected to the second air supply connector 502 of the air supply system. The air is supplied by the air supply system and can be adjusted to a high pressure state or a normal pressure state.

[0065] When the cylinder is in the deactivated state, the first air chamber 601, the second air chamber 602, the third air chamber 603 and the fourth air chamber 604 are all in a normal pressure state, the piston does not produce air flotation, the piston rod 3 does not move, and the cylinder does not provide pulling force.

[0066] When the cylinder is in a low tension state, the first air chamber 601, the second air chamber 602, and the third air chamber 603 are in a normal pressure state, and the fourth air chamber 604 is in a high pressure state. At this time, the effective piston area of ​​the cylinder is the area of ​​the lower air floating piston 2. If the area of ​​the lower air floating piston 2 is S, the air pressure can be adjusted from P to NP, so the adjustable range of the cylinder tension is PS to NPS.

[0067] When the cylinder is in the medium tension state, the first air chamber 601 and the fourth air chamber 604 are in the normal pressure state, and the second air chamber 602 and the third air chamber 603 are in the high pressure state. At this time, the effective piston area of ​​the cylinder is the area of ​​the upper air floating piston 1 minus the area of ​​the lower air floating piston 2. If the area of ​​the lower air floating piston 2 is S, the area of ​​the upper air floating piston 1 is (N+1)S, and the effective piston area of ​​the cylinder is NS. The air pressure can be adjusted from P to NP, so the adjustable range of the cylinder tension is NPS to N. 2 PS.

[0068] When the cylinder is in a high tension state, the first air chamber 601 is in a normal pressure state, and the second air chamber 602, the third air chamber 603, and the fourth air chamber 604 are in a high pressure state. At this time, the effective piston area of ​​the cylinder is the area of ​​the upper air floating piston 1. If the area of ​​the lower air floating piston 2 is S, then the area of ​​the upper air floating piston 1 is (N+1)S, and the effective piston area of ​​the cylinder is also (N+1)S. The air pressure can be adjusted from P to NP, so the adjustable range of the cylinder tension is (N+1)PS to (N 2 +N)PS.

[0069]

[0070] Table 1: Cylinder status in different working modes

[0071] 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. An air-floating cylinder with adjustable push-pull force, characterized in that: include: A cylinder barrel (6), the cylinder barrel (6) comprising an upper air chamber and a lower air chamber, wherein the cross-sectional areas of the upper air chamber and the lower air chamber are unequal; An air bearing (7), wherein the air bearing (7) is arranged at the lower end of the cylinder barrel (6); A piston rod (3), the piston rod (3) being located in the cylinder barrel (6) and being in air-floating sliding cooperation with an air-floating bearing (7) in an up-and-down manner; An upper air-floating piston (1), the upper air-floating piston (1) being arranged on the piston rod (3) and located in the upper air cavity, the upper air-floating piston (1) not being connected to the inner wall of the upper air cavity, the side wall of the upper air-floating piston (1) being surrounded by an upper piston hole (101), the upper air-floating piston (1) blowing air toward the inner wall of the upper air cavity through the upper piston hole (101), thereby making the outer wall of the upper air-floating piston (1) and the inner wall of the upper air cavity slide in an upward and downward air-floating manner; and A lower air-floating piston (2) is provided on a piston rod (3) and is located in a lower air cavity. The lower air-floating piston (2) is not connected to the inner wall of the lower air cavity. The side wall of the lower air-floating piston (2) is surrounded by a lower piston hole (201). The lower air-floating piston (2) blows air toward the inner wall of the lower air cavity through the lower piston hole (201), thereby achieving an upper and lower air-floating sliding fit between the outer wall of the lower air-floating piston (2) and the inner wall of the lower air cavity.

2. The air-floating cylinder with adjustable push-pull force according to claim 1, characterized in that: The cross-sectional area of ​​the upper air cavity is greater than the cross-sectional area of ​​the lower air cavity, and the cross-sectional area of ​​the upper air-floating piston (1) is greater than the cross-sectional area of ​​the lower air-floating piston (2).

3. The air-floating cylinder with adjustable push-pull force according to claim 1, characterized in that: The upper air-floating piston (1) has an upper piston inner cavity (102) connected to the upper piston hole (101), and the lower air-floating piston (2) has a lower piston inner cavity (202) connected to the lower piston hole (201).

4. The air-floating cylinder with adjustable push-pull force according to claim 3, characterized in that: A high-pressure gas circuit (305) is provided on the piston rod (3), and the high-pressure gas circuit (305) is used to supply gas to the upper piston inner cavity (102) and the lower piston inner cavity (202).

5. The air-floating cylinder with adjustable push-pull force according to claim 4, characterized in that: The upper air-floating piston (1) divides the upper air chamber into a first air chamber (601) and a second air chamber (602) from top to bottom. The first air chamber (601) is connected to the atmosphere or a normal pressure air source. The lower piston divides the lower air chamber into a third air chamber (603) and a fourth air chamber (604) from top to bottom. The third air chamber (603) is connected to the second air chamber (602). A first air supply connector (501) is provided on the second air chamber (602) and / or the third air chamber (603). A second air supply connector (502) is provided on the fourth air chamber (604). The high-pressure air circuit (305) is respectively connected to the upper piston inner chamber (102) and the lower piston inner chamber (202). The high-pressure air circuit (305) is connected to the fourth air chamber (604). The high-pressure air circuit (305) is also connected to the second air chamber (602) and / or the third air chamber (603).

6. The air-floating cylinder with adjustable push-pull force according to claim 5, characterized in that: A first one-way valve (302) and a second one-way valve (304) are provided on the high-pressure gas circuit (305); the first one-way valve (302) allows airflow from the second air cavity (602) and / or the third air cavity (603) to enter the high-pressure gas circuit (305), but does not allow airflow from the high-pressure gas circuit (305) to enter the second air cavity (602) and / or the third air cavity (603); the second one-way valve (304) allows airflow from the fourth air cavity (604) to enter the high-pressure gas circuit (305), but does not allow airflow from the high-pressure gas circuit (305) to enter the fourth air cavity (604).

7. The air-floating cylinder with adjustable push-pull force according to claim 5, characterized in that: An upper piston pressure relief groove (103) is provided on the outer wall of the upper air floating piston (1), and an upper piston pressure relief hole (104) communicating with the upper piston pressure relief groove (103) is provided on the upper air floating piston (1), and the upper piston pressure relief hole (104) is communicated with the first air chamber (601).

8. The air-floating cylinder with adjustable push-pull force according to claim 3, characterized in that: A lower piston pressure relief groove (203) is arranged on the outer wall of the lower air-floating piston (2); a lower piston pressure relief hole (204) connected to the lower piston pressure relief groove (203) is arranged on the lower air-floating piston (2); the lower piston pressure relief hole (204) is connected to the inner wall of the lower air-floating piston (2); a normal pressure gas path (306) is arranged on the piston rod (3); the normal pressure gas path (306) is respectively connected to the lower piston pressure relief hole (204) and the atmosphere.

9. The air-floating cylinder with adjustable push-pull force according to claim 5, characterized in that: The invention also includes an air supply system, wherein the air supply system supplies air to the fourth air cavity (604), and the air supply system also supplies air to the second air cavity (602) and / or the third air cavity (603), and comprises a high-pressure air source (503), a high-pressure pressure-stabilizing tank (504), an air filter (505), a pressure-reducing valve (506), a first three-way valve (508), a second three-way valve (509), a first air pressure sensor (510), and a second air pressure sensor (511); the high-pressure air source (503), the high-pressure pressure-stabilizing tank (504), the air filter (505), and the pressure-reducing valve (506) are sequentially connected to the air chamber (604). The pressure reducing valve (506) is connected to the first three-way valve (508) and the second three-way valve (509) through pipelines, respectively; the first three-way valve (508) is connected to the second air cavity (602) and / or the third air cavity (603) through pipelines; the first air pressure sensor (510) is used to detect the air pressure input to the second air cavity (602) and / or the third air cavity (603); the second three-way valve (509) is connected to the fourth air cavity (604) through pipelines; and the second air pressure sensor (511) is used to detect the air pressure input to the fourth air cavity (604).

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