Double-piston air floating type friction-free air cylinder

Abstract

The invention belongs to the field of air cylinders, and discloses a double-piston air floating type friction-free air cylinder which comprises a cylinder body assembly, an upper air floating bearing assembly, a piston rod, an upper piston and a lower piston. The lower piston, the upper air floatation bearing assembly and the upper piston are sequentially arranged from bottom to top and sequentially divide an inner cavity of the cylinder body assembly into a first high-pressure area, a first normal-pressure area, a second high-pressure area and a second normal-pressure area from bottom to top, a lower air floatation channel structure is arranged on the lower piston, and an upper air floatation channel structure is arranged on the upper piston. The double-piston design is adopted in the air cylinder, the two pistons are jointly used for bearing, under the conditions of the same air pressure and the same sectional area of the air cylinder, double push-pull force can be output, the size of the air cylinder can be reduced through the design, the air cylinder has higher applicability, and the bearing capacity of the pistons is improved.

Description

Technical Field

[0001] The invention relates to the field of cylinders, in particular to a double-piston air-floating frictionless cylinder. Background Art

[0002] Ordinary cylinders usually use contact seals, which have greater friction resistance when the piston moves. Using an air-floating cylinder can reduce the friction during piston movement and support the free and rapid movement of the piston.

[0003] The air-floating frictionless cylinder is usually composed of a cylinder barrel, an air-floating piston, a gas dynamic seal bearing, a cylinder shaft and other components. Two gas areas of high pressure and low pressure are formed in the cylinder, and the push-pull force of the cylinder is provided by the high and low pressure difference on both sides of the piston. For a single-layer single-piston air-floating frictionless cylinder, the push-pull force provided is: F=(P1-P2)S, where F is the push-pull force of the cylinder, P1 is the pressure of the high-pressure area, P2 is the pressure of the low-pressure area, and S is the effective area of ​​the piston.

[0004] To increase the push-pull force of the cylinder, the usual solution is to increase the piston area of ​​the cylinder and increase the pressure difference between the high and low pressure sides. When the cylinder is used in a narrow space, it is usually impossible to use a larger cylinder. Increasing the cylinder pressure not only places higher requirements on the high-pressure gas source, but also on the cylinder structure. There are many limitations to increasing the push-pull force by simply increasing the cylinder working pressure.

[0005] For air-floating frictionless cylinders, there are high requirements for the processing and installation of air-floating pistons and cylinder barrels. In order to ensure that the air-floating cylinder is always in a stable operating state, there should be no contact friction between the air-floating piston and the cylinder barrel, and the air-floating surface between the piston and the cylinder barrel must always be in a stable working state. This puts forward requirements for the installation accuracy of the cylinder. The gap between the cylinder barrel and the air-floating piston must be guaranteed to be the same as the target air film thickness. If the gap between the cylinder barrel and the air-floating piston is too small, the piston and the cylinder barrel will produce contact friction, which will damage the cylinder structure and affect the stability of the cylinder. If the gap between the cylinder barrel and the air-floating piston is too large, the gas in the high-pressure area will quickly leak to the low-pressure area, which will not only increase the amount of gas leakage, but also be detrimental to the normal operation of the piston surface. For the commonly used round cylinder, the processing accuracy of the round cylinder barrel is low during processing, and during transportation and use, the round cylinder barrel will produce large deformation, which is not conducive to the use of the air-floating cylinder.

[0006] During operation, the air-floating frictionless cylinder will be affected by lateral push-pull force or torque. The air-floating piston needs to offset the corresponding lateral force and torque, maintain the normal formation of the air-floating surface between the piston and the cylinder, and thus ensure the normal operation of the air-floating cylinder. In the conventional cylinder structure, the output shaft and piston of the cylinder are both contact-sealed, which have strong resistance to lateral force and torque, and do not require special design to resist lateral force. For air-floating cylinders, since the air-floating bearing itself has weak resistance to lateral force and torque, when the cylinder bearing is subjected to a slightly larger lateral force, it exceeds the maximum bearing capacity of the air-floating surface between the cylinder and the air-floating piston, and the cylinder and the air-floating piston produce contact friction. Based on this, the air-floating cylinder must be specially designed to bear lateral force and torque, so as to enhance the stability of the cylinder. Summary of the invention

[0007] The purpose of the present invention is to provide a double-piston air-floating frictionless cylinder to solve the problems raised in the above background technology.

[0008] To achieve the above object, the present invention provides the following technical solutions: A double-piston air-floating frictionless cylinder, comprising a cylinder assembly, an upper air-floating bearing assembly, a piston rod, an upper piston and a lower piston, wherein the upper air-floating bearing assembly is arranged in the cylinder assembly, the piston rod is slidably inserted in the upper air-floating bearing assembly up and down, the upper piston and the lower piston are arranged on the piston rod at intervals up and down, the outer walls of the upper piston and the lower piston do not contact the inner wall of the cylinder assembly, the lower piston, the upper air-floating bearing assembly and the upper piston are arranged in sequence from bottom to top, and the inner cavity of the cylinder assembly is divided into a first high-pressure area, a second high-pressure area and a third high-pressure area in sequence from bottom to top. A normal pressure zone, a second high pressure zone, and a second normal pressure zone, the first high pressure zone and the second high pressure zone are connected to a high pressure gas supply system, the first normal pressure zone and the second normal pressure zone are connected to the atmosphere or a low pressure gas source, a lower air flotation channel structure is arranged on the lower piston, the lower air flotation channel structure transmits the high pressure gas of the first high pressure zone to the side wall of the lower piston and blows it to the inner wall of the cylinder assembly, an upper air flotation channel structure is arranged on the upper piston, the upper air flotation channel structure transmits the high pressure gas of the second high pressure zone to the side wall of the upper piston and blows it to the inner wall of the cylinder assembly.

[0009] Furthermore, a high-pressure connecting groove is provided on the cylinder assembly, the high-pressure connecting groove communicates with the first high-pressure area and the second high-pressure area, and the high-pressure connecting groove is connected to a high-pressure gas supply system.

[0010] Furthermore, the lower air flotation channel structure includes a plurality of lower air flotation holes distributed on the outer wall of the lower piston and a plurality of lower air supply holes arranged on the bottom of the lower piston, the lower air flotation holes are connected to the lower air supply holes, and the lower air supply holes are connected to the first high pressure area.

[0011] Furthermore, the upper air flotation channel structure includes a plurality of upper air flotation holes distributed on the outer wall of the upper piston and a plurality of upper air supply holes arranged on the bottom of the upper piston, the upper air flotation holes are connected to the upper air supply holes, and the upper air supply holes are connected to the second high pressure area.

[0012] Furthermore, the upper air bearing assembly includes a bearing base plate arranged in the cylinder assembly, an upper bearing seat arranged on the bearing base plate, and an upper air bearing body arranged in the upper bearing seat, and the piston rod is air-floatingly rotatably plugged into the upper air bearing body.

[0013] Furthermore, the cylinder assembly includes a cylinder barrel, a base arranged at the bottom of the cylinder barrel, and a cover plate arranged at the top of the cylinder barrel.

[0014] Furthermore, the base includes a bottom plate fixedly connected to the cylinder, a lower bearing seat arranged on the bottom plate, and a lower air-floating bearing body arranged in the lower bearing seat, and the piston rod is air-floatingly rotatably plugged into the lower air-floating bearing body.

[0015] Furthermore, the first normal pressure zone and the second normal pressure zone are provided with normal pressure ports for connecting to the atmosphere.

[0016] Compared with the prior art, the present invention has the following beneficial effects: 1) The cylinder adopts a double-piston design. The two pistons carry the load together. Under the same air pressure and cylinder cross-sectional area, it can output twice the push and pull force. This design can reduce the cylinder size, make the cylinder more applicable, and increase the piston load-bearing capacity; 2) The cylinder adopts a double-piston design. The two pistons jointly bear the lateral force and lateral torque, which enhances the piston's anti-lateral ability and ensures that the piston can still form a stable air-floating surface under the condition of large lateral force and torque, avoiding contact friction between the air-floating piston and the cylinder wall; 3) Use air-floating cylinders, and both bearings and pistons are fixed with non-contact air-floating surfaces. The cylinders do not generate contact friction during operation, which can reduce cylinder friction and increase cylinder service life; 4) A high-pressure connecting groove is designed on the cylinder to connect the upper and lower high-pressure areas. Air is supplied through the same pipeline to ensure the consistency of air pressure in the upper and lower high-pressure areas. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of the structure of the present invention.

[0018] Figure 2 It is a schematic diagram of the decomposition structure of the present invention.

[0019] Figure 3 It is a schematic diagram of the cross-sectional structure of the present invention.

[0020] Figure 4This is one of the schematic diagrams of the upper piston structure in the present invention.

[0021] Figure 5 This is the second schematic diagram of the upper piston structure in the present invention.

[0022] Figure 6 This is one of the schematic diagrams of the cross-sectional structure of the upper piston in the present invention.

[0023] Figure 7 This is the second schematic diagram of the cross-sectional structure of the upper piston in the present invention.

[0024] Figure 8 This is one of the schematic diagrams of the lower piston structure of the present invention.

[0025] Fig. 9 This is the second schematic diagram of the lower piston structure of the present invention.

[0026] Fig.10 This is one of the schematic diagrams of the cross-sectional structure of the lower piston in the present invention.

[0027] Fig.11 This is the second schematic diagram of the cross-sectional structure of the lower piston in the present invention.

[0028] In the figure: Cylinder 1; Bottom plate 2; Bearing plate 3; Upper air bearing body 4; Lower air bearing body 5; Piston rod 6; Upper piston 7, upper air floating hole 700, upper air supply hole 701, upper piston pressure relief groove 702, upper piston pressure relief channel 703; Lower piston 8, lower air floating hole 800, lower air supply hole 801, lower piston pressure relief groove 802, lower piston pressure relief channel 803; The first high pressure area 9; The first normal pressure zone 10; The second high pressure area 11; The second normal pressure zone 12; High-pressure connection groove 13; Upper bearing seat 14; Lower bearing seat 15; Normal pressure port 16; High pressure gas supply connector 17; Cover plate 18. DETAILED DESCRIPTION

[0029] 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.

[0030] See also Figure 1-Figure 11 A double-piston air-floating frictionless cylinder comprises a cylinder assembly, an upper air-floating bearing assembly, a piston rod 6, an upper piston 7 and a lower piston 8. The upper air-floating bearing assembly is arranged in the cylinder assembly, the piston rod 6 is inserted in the upper air-floating bearing assembly by sliding up and down, the upper piston 7 and the lower piston 8 are arranged on the piston rod 6 at intervals up and down, the outer walls of the upper piston 7 and the lower piston 8 do not contact the inner wall of the cylinder assembly, the lower piston 8, the upper air-floating bearing assembly and the upper piston 7 are arranged in sequence from bottom to top, and the inner cavity of the cylinder assembly is divided into a first high-pressure area 9 and a first normal-pressure area in sequence from bottom to top. 10, a second high-pressure zone 11, and a second normal-pressure zone 12. The first high-pressure zone 9 and the second high-pressure zone 11 are connected to a high-pressure gas supply system. A normal-pressure port 16 for connecting to the atmosphere is provided on the first normal-pressure zone 10 and the second normal-pressure zone 12. A lower air flotation channel structure is provided on the lower piston 8. The lower air flotation channel structure transmits the high-pressure gas in the first high-pressure zone 9 to the side wall of the lower piston 8 and blows it toward the inner wall of the cylinder assembly. An upper air flotation channel structure is provided on the upper piston 7. The upper air flotation channel structure transmits the high-pressure gas in the second high-pressure zone 11 to the side wall of the upper piston 7 and blows it toward the inner wall of the cylinder assembly.

[0031] Continue reading Figure 1-Figure 3 In one embodiment of the present invention, the cylinder assembly includes a cylinder barrel 1 , a base disposed at the bottom of the cylinder barrel 1 , and a cover plate 18 disposed at the top of the cylinder barrel 1 .

[0032] Continue reading Figure 3 In one embodiment of the present invention, the base includes a bottom plate 2 fixedly connected to the cylinder 1, a lower bearing seat 15 arranged on the bottom plate 2, and a lower air-floating bearing body 5 arranged in the lower bearing seat 15, and the piston rod 6 is air-floatingly rotatably plugged into the lower air-floating bearing body 5.

[0033] Continue reading Figure 3 In one embodiment of the present invention, the upper air-floating bearing assembly includes a bearing base plate 3 fixedly connected to the cylinder 1, an upper bearing seat 14 arranged on the bearing base plate 3, and an upper air-floating bearing body 4 arranged in the upper bearing seat 14, and the piston rod 6 is air-floatingly rotatably plugged into the upper air-floating bearing body 4.

[0034] Continue reading Figure 3In one embodiment of the present invention, a high-pressure connecting groove 13 is provided on the cylinder 1, and the high-pressure connecting groove 13 connects the first high-pressure area 9 and the second high-pressure area 11. A high-pressure gas supply connector 17 is provided on the high-pressure connecting groove 13, and is connected to the high-pressure gas supply system through the high-pressure gas supply connector 17.

[0035] In another embodiment of the present invention, a high-pressure gas supply connector 17 may be installed in each of the first high-pressure area 9 and the second high-pressure area 11 to connect to the high-pressure gas supply system.

[0036] Continue reading Figure 4-Figure 7 In one embodiment of the present invention, the upper air flotation channel structure includes a plurality of upper air flotation holes 700 arranged on the outer wall of the upper piston 7 and a plurality of upper air supply holes 701 arranged on the bottom of the upper piston 7. The upper air flotation holes 700 correspond to the arrangement of the upper air supply holes 701. One upper air supply hole 701 is connected to one or more upper air flotation holes 700 at corresponding positions, and the bottom of the upper air supply hole 701 is connected to the second high-pressure area 11.

[0037] Continue reading Figure 4-Figure 7 In one embodiment of the present invention, two annular upper piston pressure relief grooves 702 are arranged on the upper and lower outer walls of the upper piston 7, the upper air flotation hole 700 is arranged in the area between the upper and lower upper piston pressure relief grooves 702, and a plurality of upper piston pressure relief channels 703 connected to the upper and lower upper piston pressure relief grooves 702 are evenly distributed on the upper piston 7, and the upper ends of the upper piston pressure relief channels 703 are connected to the second normal pressure area 12.

[0038] An air flotation surface is formed between the upper piston 7 and the inner wall of the cylinder 1. When the cylinder is running, the air flotation surface of the upper piston 7 works, and the gas discharged from the air flotation surface flows into the second normal pressure area 12 through the upper piston pressure relief groove 702 and the upper piston pressure relief channel 703, and then flows into the ambient atmosphere.

[0039] Continue reading Figure 8-Figure 11 In one embodiment of the present invention, the lower air flotation channel structure includes a plurality of lower air flotation holes 800 arranged on the outer wall of the lower piston 8 and a plurality of lower air supply holes 801 arranged on the bottom of the lower piston 8. The lower air flotation holes 800 correspond to the arrangement of the lower air supply holes 801. One lower air supply hole 801 is connected to one or more lower air flotation holes 800 at corresponding positions, and the bottom of the lower air supply hole 801 is connected to the first high-pressure area 9.

[0040] Continue reading Figure 8-Figure 11 In one embodiment of the present invention, two lower piston pressure relief grooves 802 are arranged on the upper and lower outer walls of the lower piston 8, the lower air flotation hole 800 is arranged in the area between the upper and lower lower piston pressure relief grooves 802, and a plurality of lower piston pressure relief channels 803 connected to the upper and lower lower piston pressure relief grooves 802 are evenly distributed on the lower piston 8, and the upper ends of the lower piston pressure relief channels 803 are connected to the first normal pressure area 10.

[0041] An air flotation surface is formed between the lower piston 8 and the inner wall of the cylinder 1. When the cylinder is running, the air flotation surface of the lower piston 8 works, and the gas discharged from the air flotation surface flows into the first normal pressure area 10 through the lower piston pressure relief groove 802 and the lower piston pressure relief channel 803, and then flows into the ambient atmosphere.

[0042] Further explanation of the base: The base is the basic component of the cylinder, and the rest of the structure is installed on the base as a whole. The cylinder as a whole is fixed to other equipment in the working area through the threaded holes of the base bottom plate. The base is divided into two parts: the base plate 2 and the air seal. The air seal is a well-known technology, which is composed of a lower bearing seat 15 and a lower air-floating bearing body 5. The base plate 2 is a circular thick plate with a circular hole in the center to provide space for the piston rod to extend out of the cylinder. There are threaded holes on the base plate 2 to fix it to the cylinder barrel 1, threaded holes to fix it to the lower bearing seat 15, and threaded holes to fix it to other equipment. The air seal is installed on the base plate 2, and the structure is a cylindrical gas bearing. The inner side of the air seal is an air-floating surface, and an air film is formed between the inner side and the piston rod 6. Without contact friction, the gas in the high-pressure chamber of the cylinder is sealed, and the cylinder shaft is allowed to move axially in a frictionless linear manner. The air seal is connected by an air pipe and uses an independent air source for air supply.

[0043] When the cylinder shaft moves to the highest point, the limit plate at the bottom of the cylinder shaft contacts the bottom plate 2 of the base, and the base serves as the upper limit of the cylinder at this time.

[0044] Further description of cylinder 1: The cylinder barrel 1 is composed of two front and rear front cylinder walls and two left and right side cylinder walls. The side cylinder walls and the front cylinder walls are both installed on the base, and the base ensures their installation accuracy. The two side cylinder walls and the two front cylinder walls are installed parallel to each other, and the side cylinder wall and the front cylinder wall are installed vertically. The installation ensures that the effective cylinder surface inside the cylinder is a square.

[0045] The two front cylinder walls have the same structure. There are reinforcing ribs on the outside of the front cylinder wall to ensure that the cylinder barrel will not deform much when the cylinder is pressurized, and will not affect the movement of the air-floating piston. There are two square openings at the top and middle of the front cylinder wall, connecting the cylinder normal pressure area with the ambient atmosphere, ensuring that the air pressure in the cylinder normal pressure area is always the same as the ambient atmospheric pressure.

[0046] The two side cylinder walls have the same structure. There are reinforcing ribs on the outside of the side cylinder wall to ensure that the deformation of the cylinder barrel is small when the cylinder is pressurized and will not affect the movement of the air-floating piston. There is a high-pressure connecting groove 13 on the outside of the side cylinder wall to connect the air in the two high-pressure areas at the upper end and the lower end, so that the gas pressure in the two high-pressure areas of the cylinder always remains the same. There is an opening on the outside of the high-pressure connecting groove 13 that is connected to the high-pressure gas supply connector 17 of the high-pressure gas supply system. The high-pressure gas from the high-pressure gas supply system enters the high-pressure connecting groove 13 of the cylinder through the high-pressure gas supply connector 17 to provide gas for the two high-pressure areas of the cylinder.

[0047] Further explanation of the upper air bearing assembly: The upper air bearing assembly is installed on the groove in the middle of the inner side of the cylinder 1, and is used to isolate the air in the upper and lower high and low pressure areas. The upper air bearing assembly uses gas sealing to perform non-contact sealing of high and low pressure gases, and can also provide lateral support for the piston rod. The upper air bearing assembly isolates the upper high pressure gas from the lower normal pressure gas without generating contact friction, and allows the cylinder shaft to perform frictionless linear motion in the axial direction. The upper air bearing assembly is connected to the air source by an air pipe, and is independently air-intaken through the air source.

[0048] Further explanation of the upper piston 7 and the lower piston 8: The upper piston 7 and the lower piston 8 have the same structure. The center of the air-floating piston is fixed to the piston rod. During the movement, the piston rod moves with the air-floating piston. The upper piston 7 and the lower piston 8 are respectively installed at the upper end and the middle of the piston rod.

[0049] The air-floating piston is a square structure, with micro-pores processed through the smooth round surface on the side. Under high-pressure ventilation, the outer wall forms an air-floating surface. The air-floating surface prevents the piston from having direct contact with the cylinder, ensuring that the piston is not affected by friction resistance during movement. The air-floating piston is a semi-hollowed cube as a whole. The side of the piston is slightly smaller than the width of the inner cross-section of the cylinder, and the gap between the two is the width required for the air film. The air-floating piston is designed with two upper and lower air release grooves on the side to discharge the gas generated by the air-floating surface and ensure the stable formation of the air-floating surface. The air-floating piston uses the high-pressure area under the piston to provide air intake.

[0050] Since the two air-floating pistons are installed at fixed positions on the piston rod, a certain distance is always maintained between the two air-floating pistons. When the piston rod end is pulling an object and is subjected to lateral force and torque, the two air-floating pistons can work together to carry the lateral load. Compared with the single piston of an ordinary cylinder bearing lateral torque, the dual-piston design can prevent the piston from rotating and thus damaging the air-floating surface, greatly increasing the cylinder's ability to resist lateral force and torque.

[0051] The piston rod 6 is further described as follows: The piston rod 6 is a hollow long cylindrical structure, and the upper end and the middle part are fixed to the upper piston 7 and the lower piston 8 respectively. The lower end of the piston rod 6 is connected to the object of action as the interface of the cylinder force, and transmits the push and pull force of the cylinder to the equipment that needs to be acted on. The hollow design of the piston rod 6 ensures that the second normal pressure area 12 is at normal pressure, and at the same time can reduce the mass of the piston rod 6, thereby reducing the inertia force generated when the piston rod 6 moves.

[0052] The cover plate 18 is further described as follows: The cover plate 18 is installed on the top of the cylinder barrel 1. The cover plate 18 closes the upper end of the cylinder, isolating the normal pressure area of ​​the frictionless cylinder and the high pressure area gas outside. At the same time, the cover plate 18 is fixed to the four cylinder walls, providing position support for the top of the cylinder wall, and together with the bottom plate, ensures the installation accuracy of the four cylinder walls of the cylinder.

[0053] The present invention is used in conjunction with a high-pressure gas supply system, which is composed of a compressor, a high-pressure tank, a gas pipeline, and a high-pressure gas supply connector. High-pressure gas enters the high-pressure connecting groove 13 of the cylinder through the high-pressure gas supply connector to provide air intake for the two high-pressure areas of the cylinder.

[0054] 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 double piston air floating frictionless cylinder, characterized in that: The invention comprises a cylinder assembly, an upper air bearing assembly, a piston rod (6), an upper piston (7) and a lower piston (8), wherein the upper air bearing assembly is arranged in the cylinder assembly, the piston rod (6) is slidably inserted in the upper air bearing assembly up and down, the upper piston (7) and the lower piston (8) are arranged on the piston rod (6) at intervals up and down, the outer walls of the upper piston (7) and the lower piston (8) do not contact the inner wall of the cylinder assembly, the lower piston (8), the upper air bearing assembly and the upper piston (7) are arranged in sequence from bottom to top, and the inner cavity of the cylinder assembly is divided into a first high-pressure area (9), a first normal-pressure area (10), a second high-pressure area (11), and a second normal-pressure area (12). The first high-pressure zone (9) and the second high-pressure zone (11) are connected to a high-pressure gas supply system, and the first normal-pressure zone (10) and the second normal-pressure zone (12) are connected to the atmosphere or a low-pressure gas source. A lower air flotation channel structure is provided on the lower piston (8), and the lower air flotation channel structure transmits the high-pressure gas in the first high-pressure zone (9) to the side wall of the lower piston (8) and blows it toward the inner wall of the cylinder assembly. An upper air flotation channel structure is provided on the upper piston (7), and the upper air flotation channel structure transmits the high-pressure gas in the second high-pressure zone (11) to the side wall of the upper piston (7) and blows it toward the inner wall of the cylinder assembly.

2. A double-piston air-floating frictionless cylinder according to claim 1, characterized in that: A high-pressure connecting groove (13) is provided on the cylinder assembly, the high-pressure connecting groove (13) is in communication with the first high-pressure area (9) and the second high-pressure area (11), and the high-pressure connecting groove (13) is connected to a high-pressure gas supply system.

3. A double-piston air-floating frictionless cylinder according to claim 1, characterized in that: The lower air flotation channel structure comprises a plurality of lower air flotation holes (800) arranged in a circle on the outer wall of the lower piston (8) and a plurality of lower air supply holes (801) arranged on the bottom of the lower piston (8); the lower air flotation holes (800) are in communication with the lower air supply holes (801); and the lower air supply holes (801) are in communication with the first high pressure area (9).

4. A double-piston air-floating frictionless cylinder according to claim 1, characterized in that: The upper air flotation channel structure comprises a plurality of upper air flotation holes (700) arranged in a ring on the outer wall of the upper piston (7) and a plurality of upper air supply holes (701) arranged on the bottom of the upper piston (7); the upper air flotation holes (700) are in communication with the upper air supply holes (701); and the upper air supply holes (701) are in communication with the second high pressure area (11).

5. A double-piston air-floating frictionless cylinder according to claim 1, characterized in that: The upper air-floating bearing assembly comprises a bearing base plate (3) arranged in the cylinder assembly, an upper bearing seat (14) arranged on the bearing base plate (3), and an upper air-floating bearing body (4) arranged in the upper bearing seat (14); the piston rod (6) is air-floatingly rotatably plugged into the upper air-floating bearing body (4).

6. A double-piston air-floating frictionless cylinder according to claim 1, characterized in that: The cylinder assembly comprises a cylinder barrel (1), a base arranged at the bottom of the cylinder barrel (1), and a cover plate (18) arranged at the top of the cylinder barrel (1).

7. A double-piston air-floating frictionless cylinder according to claim 6, characterized in that: The base comprises a bottom plate (2) fixedly connected to the cylinder (1), a lower bearing seat (15) arranged on the bottom plate (2), and a lower air-floating bearing body (5) arranged in the lower bearing seat (15); the piston rod (6) is air-floatingly rotatably plugged into the lower air-floating bearing body (5).

8. A double-piston air-floating frictionless cylinder according to claim 1, characterized in that: The first normal pressure zone (10) and the second normal pressure zone (12) are provided with normal pressure ports (16) for connecting to the atmosphere.

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