An air-floating frictionless cylinder

Abstract

The present application provides an air-floating frictionless cylinder. The cylinder includes a cylinder body, a motion component, and an air bearing. The cylinder body includes a cylinder barrel and a front cover and a rear cover fixed at both ends of the cylinder barrel. The motion component includes an air bearing, a connector, a floating joint, and a piston rod. The air bearing, connector, floating joint, and piston rod are arranged in sequence in the direction from the rear cover to the front cover. The air bearing, connector, and floating joint are located in the cylinder barrel. The piston rod passes through the front cover and is partially located in the cylinder barrel. The air bearing is located in the front cover and is sleeved on the piston rod. An air film is formed between the air bearing and the inner wall of the cylinder barrel, and an air film is formed between the air bearing and the inner wall of the front cover. Therefore, friction caused by direct contact between the air bearing and the inner wall of the cylinder barrel can be avoided. In addition, the connector and the piston rod are connected by a floating joint, which avoids the phenomenon that the piston rod and the floating bearing may be non-coaxial and stuck in the cylinder barrel.

Description

Technical Field

[0001] The present application relates to the technical field of cylinders, and in particular to an air-floating frictionless cylinder. Background Art

[0002] Pneumatics is an engineering technology that uses compressed air as the working medium to transmit energy and signals. With the continuous development of industrial automation, people are increasingly concerned about environmental protection, safety, and efficiency in production processes. Pneumatics, with its advantages such as pollution-free operation, anti-magnetic, explosion-proof, fire-proof, simple structure, and ease of use, has found widespread application in the food and pharmaceutical, automotive, electronics and semiconductor, bioengineering, and aerospace industries.

[0003] However, due to the lack of self-lubricating properties of gaseous media, pneumatic control systems face greater frictional issues than hydraulic or electronic control systems, presenting greater challenges. Friction not only complicates pneumatic servo control but also creates issues for the cylinder itself, such as heat generation, noise, vibration, dust, and reduced lifespan, posing safety risks to the pneumatic system. Therefore, low-friction or even frictionless cylinders have become a new direction in cylinder development. Summary of the Invention

[0004] In response to the shortcomings of existing air-floating cylinders, this application proposes an air-floating frictionless cylinder, which can not only form an air film between the air-floating bearing and the inner wall of the cylinder to achieve a frictionless effect; but also the connector and the piston rod are connected by a floating joint. The use of the floating joint allows a certain angle between the axis of the piston rod and the axis of the air-floating bearing, avoiding the phenomenon that the piston rod may become non-coaxial and get stuck in the cylinder.

[0005] The present application provides an air-floating frictionless cylinder, which includes:

[0006] A cylinder body, comprising a cylinder barrel and a front end cover and a rear end cover fixed at both ends of the cylinder barrel; a motion assembly, comprising an air bearing, a connector, a floating joint, and a piston rod, wherein the air bearing, the connector, the floating joint, and the piston rod are arranged in sequence in the direction from the rear end cover to the front end cover, the air bearing, the connector, and the floating joint are located in the cylinder barrel, and the piston rod passes through the front end cover and is partially located in the cylinder barrel;

[0007] An air bearing, the air bearing being located in the front end cover and sleeved on the piston rod;

[0008] The air bearing is fixedly connected to the first end of the connector, the second end of the connector is connected to the first end of the floating joint and can move radially within the floating joint along the cylinder, and the second end of the floating joint is fixedly connected to the piston rod;

[0009] A first pneumatic joint is provided on the portion of the piston rod located outside the front end cover, a second pneumatic joint is provided on the end of the piston rod located in the cylinder, a third pneumatic joint is provided on the connector, and the first pneumatic joint is communicated with the second pneumatic joint, and the second pneumatic joint is communicated with the third pneumatic joint, so that the inner cavity of the air bearing is communicated with the first pneumatic joint, and a fourth pneumatic joint is provided on the rear end cover, and the fourth pneumatic joint is communicated with the inner cavity of the cylinder;

[0010] The air bearing is provided with a throttle hole, and the gas in the air bearing is ejected through the throttle hole to form an air film between the air bearing and the inner wall of the cylinder;

[0011] The front end cover is provided with a fifth pneumatic joint and a sixth pneumatic joint, and the fifth pneumatic joint and the sixth pneumatic joint form an air film between the air bearing and the inner wall of the front end cover.

[0012] Optionally, the front end cover is penetrated by a step hole along the axial direction of the cylinder, and the step hole includes a first step hole and a second step hole located on the side of the first step hole away from the cylinder, the aperture of the first step hole is larger than the outer diameter of the piston rod, and the aperture of the second step hole is larger than the outer diameter of the air bearing.

[0013] Optionally, a first air duct and a first threaded hole are respectively provided on the piston rod, two ends of the first air duct are respectively connected to the first pneumatic joint and the first threaded hole, and the second pneumatic joint is engaged with the first threaded hole; a second threaded hole is provided on the connector, the third pneumatic joint is engaged with the second threaded hole, and the second pneumatic joint and the third pneumatic joint are connected through a hose; a cone is provided at one end of the piston rod located in the cylinder body and the first air duct extends into the cone, and a piston rod air outlet hole is provided on the cone, which is axially arranged along the radial direction of the cone and connected to the first air duct.

[0014] Optionally, the connector is integrally formed and includes a first rod portion, a step portion and a second rod portion arranged in sequence in the axial direction of the cylinder; the step portion includes a first step portion and a second step portion, the outer diameter of the first step portion is smaller than the outer diameter of the second step portion, and the first step portion is provided with an external thread so that the first step portion can be threadedly connected to the air bearing thread.

[0015] Optionally, the second threaded hole is located on the side of the second step portion away from the rear end cover, and the number of the second threaded holes is two; a second air duct is provided on the step portion, and the second air duct is connected to one of the second threaded holes, so that the second air duct is connected to the first air duct; a third air duct is provided on the first rod portion extending into the step portion, and the third air duct is connected to another second threaded hole, so that the third air duct is connected to the first air duct.

[0016] Optionally, a first groove is provided on the end surface of the first step portion close to the rear end cover, and a first sealing ring is provided in the first groove; an annular boss is provided at one end of the first rod portion close to the rear end cover, and a second groove is provided on the end surface of the annular boss close to the rear end cover, and a second sealing ring is provided in the second groove.

[0017] Optionally, the air-floating bearing is integrally formed and includes a bearing side wall, a bearing pressure-bearing wall close to the rear end cover, and a bearing limiting wall close to the front end cover. The bearing side wall and the bearing limiting wall form a third cavity, and a fourth cavity is formed on the bearing pressure-bearing wall. The inner cavity of the air-floating bearing includes the third cavity and the fourth cavity, and the axes of the third cavity and the fourth cavity coincide with the axis of the cylinder; the throttle hole is provided on the bearing side wall and is connected to the third cavity, and the side surface of the bearing pressure-bearing wall is provided with a first drain hole connected to the fourth cavity. pressure groove, the first pressure relief groove is annular and the center of the first pressure relief groove is located on the axis of the cylinder; a fourth threaded hole is provided on the bearing limiting wall, and the fourth threaded hole is engaged with the external thread of the first step portion of the connector so that the air floating bearing is fixedly connected to the connector. After the air floating bearing is assembled with the connector, the first sealing ring contacts the outer surface of the air floating bearing close to the bearing limiting wall, the second sealing ring contacts the inner surface of the bearing pressure wall, the third air duct is connected to the third cavity, and the fourth air duct is connected to the fourth cavity.

[0018] Optionally, a second pressure relief groove is provided on the side of the bearing side wall away from the bearing pressure-bearing wall, the second pressure relief groove is annular and the center of the second pressure relief groove is located on the axis of the cylinder; the first pressure relief groove and the second pressure relief groove are connected through a fifth air duct located in the bearing side wall.

[0019] Optionally, the throttle holes are distributed on the bearing side wall in three rows of six holes.

[0020] Optionally, the bearing side wall is provided with pressure equalizing grooves corresponding one to one with the throttle holes, and the pressure equalizing grooves are circular grooves, and the center of each pressure equalizing groove coincides with the center of one of the throttle holes.

[0021] The beneficial technical effects brought about by the technical solutions provided by the embodiments of the present application are:

[0022] (1) In the air-floating frictionless cylinder provided by the present application, an air film is formed between the air-floating bearing and the inner wall of the cylinder, and an air film is formed between the air-floating bearing and the inner wall of the front end cover. Therefore, friction caused by direct contact between the air-floating bearing and the inner wall of the cylinder can be avoided, and friction caused by contact between the air-floating bearing and the inner wall of the front end cover can also be avoided, thereby improving or even solving the problem of increasing the difficulty of pneumatic servo control due to friction, and improving or even solving problems such as heat, noise, vibration, dust, and affecting the service life of the cylinder; and the connector and the piston rod are connected by a floating joint, Since the connector can move radially within the cylinder within the floating joint, the floating joint allows a certain angle between the piston rod axis and the air bearing axis, thus avoiding the piston rod from becoming non-coaxial and getting stuck in the cylinder. Since the inner cavity of the air bearing is connected to the first pneumatic joint, the air pressure in the air bearing can always be consistent with the air pressure in the high-pressure chamber of the cylinder. This solves the air supply problem of the traditional air bearing and further realizes the bidirectional operation of the cylinder. Since the air supply of the air bearing and the piston rod is relatively independent, their respective stable operation is guaranteed.

[0023] (2) In the air-floating frictionless cylinder provided in the embodiment of the present application, the air-floating bearing adopts three rows of six-hole throttle holes, and pressure relief grooves are provided at the front and rear ends of the air-floating bearing to ensure that the gas is evenly distributed in the bearing and to release excess gas pressure when necessary;

[0024] (3) In the air-floating frictionless cylinder provided in the embodiment of the present application, a first sealing ring and a second sealing ring are provided on the connector. After the connector and the air-floating bearing are assembled, the first sealing ring and the second sealing ring can increase the air tightness in the air-floating bearing, thereby being able to more accurately control the air pressure in the cylinder body and the air-floating bearing to obtain a better servo control effect;

[0025] (4) In the air-floating frictionless cylinder provided in this embodiment, the "through hole + plug" design can simplify the processing difficulty of the second air channel and the third air channel in the connector.

[0026] Additional aspects and advantages of the present application will be given in part in the following description, which will become apparent from the following description, or will be learned through practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the following description of the embodiments in conjunction with the accompanying drawings, in which:

[0028] Figure 1A schematic structural diagram of an air-floating frictionless cylinder provided in an embodiment of the present application;

[0029] Figure 2 A schematic cross-sectional view of the front end cover of the air-floating frictionless cylinder provided in an embodiment of the present application;

[0030] Figure 3 A schematic cross-sectional view of a piston rod in an air-floating frictionless cylinder provided in an embodiment of the present application;

[0031] Figure 4 A schematic cross-sectional view of a connector in an air-floating frictionless cylinder provided in an embodiment of the present application;

[0032] Figure 5 A schematic diagram of the structure of an air-floating bearing in an air-floating frictionless cylinder provided in an embodiment of the present application;

[0033] Figure 6 This is a schematic structural diagram of the floating joint provided in an embodiment of the present application.

[0034] Reference numerals:

[0035] 1-cylinder body; 11-cylinder barrel; 12-front end cover; 121-fifth pneumatic joint; 122-sixth pneumatic joint; 123-connecting portion; 124-first step hole; 125-second step hole; 13-rear end cover, 131-fifth chamber; 132-fourth pneumatic joint;

[0036] 2-piston rod; 21-first air channel; 22-connecting end; 23-truncated cone; 231-piston rod air outlet; 232-first threaded hole; 233-third threaded hole; 234-second pneumatic joint; 24-first pneumatic joint;

[0037] 3 - Connector; 31 - First rod; 311 - Third air channel; 312 - Annular boss; 3121 - First groove, 3122 - First sealing ring; 32 - Step; 321 - First step; 322 - Second step; 3221 - Second threaded hole; 3222 - First through hole; 3223 - First plug; 3224 - Second through hole; 3225 - Second plug; 3226 - Second groove; 3227 - Second sealing ring; 3228 - Third pneumatic connector; 323 - Second air channel; 33 - Second rod; 331 - Connector tail end;

[0038] 4-Floating joint;

[0039] 5-air bearing; 51-bearing side wall; 511-throttle hole; 512-pressure equalizing groove; 513-radial blind hole; 514-fourth air channel; 515-second pressure relief groove; 52-bearing pressure-bearing wall; 521-first pressure relief groove; 53-bearing limiting wall; 531-fourth threaded hole; 54-third cavity; 55-fourth cavity;

[0040] 6- Air bearing. DETAILED DESCRIPTION

[0041] The present application is described in detail below. Examples of embodiments of the present application are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar components or components having the same or similar functions. In addition, if the detailed description of the known technology is not necessary for the features of the present application shown, it will be omitted. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application and are not to be construed as limiting the present application.

[0042] It will be understood by those skilled in the art that, unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by those skilled in the art to which this application belongs. It should also be understood that terms such as those defined in common dictionaries should be understood to have meanings consistent with their meanings in the context of the prior art and will not be interpreted in an idealized or overly formal sense unless specifically defined as herein.

[0043] Those skilled in the art will appreciate that, unless otherwise stated, the singular forms "a," "an," "said," and "the" used herein may also include plural forms. It should be further understood that the term "comprising" used in the specification of this application refers to the presence of features, integers, operations, elements, and / or components, but does not preclude the presence or addition of one or more other features, integers, operations, elements, components, and / or combinations thereof.

[0044] However, in pneumatic servo control applications, traditional cylinders face new challenges. The compressibility of gas increases the difficulty of precise cylinder control, while friction causes performance degradation at low speeds. Because gas media lacks self-lubrication, pneumatic control systems face greater friction than hydraulic or electronic control systems, posing even greater challenges.

[0045] In addition to complicating pneumatic servo control, friction also creates problems for the cylinder itself, such as heat generation, noise, vibration, dust, and reduced lifespan, posing safety risks to pneumatic systems. Therefore, reducing friction and developing new low-friction or even frictionless cylinders has become a new direction in cylinder development. However, newly developed air-floating low-friction and even frictionless cylinders still face many challenges. For example, the piston rod and air-floating bearing are prone to seizure due to the radial force of the cylinder barrel, which can damage the cylinder and even cause accidents in the equipment using the cylinder.

[0046] Based on the above technical problems, this embodiment provides an air-floating frictionless cylinder, in which the connector connected to the air-floating bearing is connected to the piston rod through a floating joint, wherein one end of the connector is connected to the floating joint and can move radially within the floating joint along the cylinder barrel, thereby preventing the piston rod and the air-floating bearing from being easily stuck under the action of the radial force of the cylinder barrel, which is beneficial to prolonging the service life of the cylinder and avoiding accidents of related equipment caused by radial force sticking. Figure 1 To the attached Figure 5 The air-floating frictionless cylinder provided in this embodiment is described.

[0047] The air-floating frictionless cylinder provided in this embodiment is as follows: Figure 1 As shown, the air-floating frictionless cylinder includes a cylinder body 1, a motion component and an air bearing 6.

[0048] like Figure 1 As shown, in the air-floating frictionless cylinder provided in this embodiment, the cylinder body 1 includes a cylinder barrel 11 and a front end cover 12 and a rear end cover 13 fixed at both ends of the cylinder barrel 11. Specifically, as Figure 1 and Figure 2 As shown, one end of the front cover 12 is a connecting portion 123. The connecting portion 123 has a small diameter and is adapted to the inner diameter of the cylinder 11. In some specific embodiments, the front cover 12 and the cylinder 11 are connected by a threaded engagement. Similarly, the connection method of the rear cover 13 and the cylinder 11 can be similar to the connection method of the front cover 12 and the cylinder 11.

[0049] like Figure 1 As shown, in the air-floating frictionless cylinder provided in this embodiment, the motion components include an air-floating bearing 5, a connector, a floating joint 4 and a piston rod 2. The air-floating bearing 5, the connector, the floating joint 4 and the piston rod 2 are arranged in sequence in the direction from the rear end cover 13 to the front end cover 12 of the air-floating bearing 5. The air-floating bearing 5, the connector and the floating joint 4 are located in the cylinder barrel 11, and the piston rod 2 passes through the front end cover 12 and is partially located in the cylinder barrel 11.

[0050] like Figure 1As shown, in the air-floating frictionless cylinder provided in this embodiment, the air bearing 6 is located in the front end cover 12 and is sleeved on the piston rod 2.

[0051] like Figure 1 As shown, in the air-floating frictionless cylinder provided in this embodiment, the air-floating bearing 5 is fixedly connected to the first end of the connector, the second end of the connector is connected to the first end of the floating joint 4 and can move radially along the cylinder 11 in the floating joint 4, and the second end of the floating joint 4 is fixedly connected to the piston rod 2.

[0052] like Figure 1 As shown, in the air-floating frictionless cylinder provided in this embodiment, a first pneumatic joint 24 is provided on the part of the piston rod 2 located outside the front end cover 12, a second pneumatic joint 234 is provided on the end of the piston rod 2 located in the cylinder 11, and a third pneumatic joint 3228 is provided on the connector 3, so that the inner cavity of the air-floating bearing 5 is connected with the first pneumatic joint 24, and the first pneumatic joint 24 is connected with the second pneumatic joint 234, and the second pneumatic joint 234 is connected with the third pneumatic joint 3228, and a fourth pneumatic joint 132 is provided on the rear end cover 13 and the fourth pneumatic joint 132 is connected with the inner cavity of the cylinder body 1.

[0053] Specifically, a fifth cavity 131 is provided in the rear end cover 13 , and the fifth cavity 131 is communicated with the fourth pneumatic joint 132 , so that the fourth pneumatic joint 132 is communicated with the cavity between the air bearing 5 in the cylinder body 1 and the rear end cover 13 .

[0054] like Figure 1 As shown, in the air-floating frictionless cylinder provided in this embodiment, a throttle hole 511 is provided on the air-floating bearing 5, and the gas inside is ejected through the throttle hole 511 to form an air film between the air-floating bearing 5 and the inner wall of the cylinder 11; a fifth pneumatic joint 121 and a sixth pneumatic joint 122 are provided on the front end cover 12, and the fifth pneumatic joint 121 and the sixth pneumatic joint 122 form an air film between the air bearing 6 and the inner wall of the front end cover 12.

[0055] In the air-floating frictionless cylinder provided by this embodiment, an air film is formed between the air-floating bearing 5 and the inner wall of the cylinder barrel 11, and an air film is formed between the air-floating bearing 5 and the inner wall of the cylinder barrel 11, and an air film is formed between the air-floating bearing 6 and the inner wall of the front end cover 12. Therefore, the friction caused by direct contact between the air-floating bearing 5 and the inner wall of the cylinder barrel 11 can be avoided, and the friction caused by contact between the air-floating bearing 6 and the inner wall of the front end cover 12 can also be avoided, thereby improving or even solving the problem of increasing the difficulty of pneumatic servo control due to friction, and improving or even solving the problems of heat generation, noise, vibration, dust, and affecting the service life of the cylinder; and the connector and the piston rod 2 are connected by a floating joint 4. Since the connection The connector can move radially within the cylinder 11 within the floating joint 4, that is, the application of the floating joint 4 allows a certain angle between the axis of the piston rod 2 and the axis of the air bearing 5, thereby avoiding the phenomenon that the piston rod 2 may be non-coaxial and stuck in the cylinder 11; since the inner cavity of the air bearing 5 is connected to the first pneumatic joint 24, the air pressure in the air bearing 5 can always be consistent with the air pressure in the high-pressure chamber in the cylinder body 1, thereby solving the air supply problem of the traditional air bearing 5 and further realizing the bidirectional operation of the cylinder; since the air supply of the air bearing 6 and the piston rod 2 is relatively independent, their respective stable operation is guaranteed.

[0056] like Figure 1 and Figure 2 As shown, in the air-floating frictionless cylinder provided in this embodiment, the front end cover 12 is penetrated by a stepped hole along the axis of the cylinder barrel 11. The stepped hole includes a first stepped hole 124 and a second stepped hole 125 located on the side of the first stepped hole 124 away from the cylinder barrel 11. The diameter of the first stepped hole 124 is larger than the outer diameter of the piston rod 2, and the diameter of the second stepped hole 125 is larger than the outer diameter of the air bearing 6. Specifically, an air film is formed between the piston rod 2 and the inner walls of the front end cover 12 and the inner walls of the cylinder barrel 11, thereby preventing friction between the piston rod 2, the inner walls of the front end cover 12, and the inner walls of the cylinder barrel 11. It should be noted that the centers of the first stepped hole 124 and the second stepped hole 125 are both located on the axis of the cylinder barrel 11.

[0057] like Figure 1 、 Figure 3 and Figure 4 As shown, in the air-floating frictionless cylinder provided in this embodiment, a first air channel 21 and a first threaded hole 232 are respectively provided on the piston rod 2, and the two ends of the first air channel 21 are respectively connected to the first pneumatic joint 24 and the first threaded hole 232, and the second pneumatic joint 234 is engaged with the first threaded hole 232; a second threaded hole 3221 is provided on the connector 3, and the third pneumatic joint 3228 is engaged with the second threaded hole 3221; the second pneumatic joint 234 and the third pneumatic joint 3228 are connected through a hose.

[0058] It should be noted that although the pneumatic connector provided in this embodiment (including the first to sixth pneumatic connectors) is connected to the piston rod 2, connector, front end cover 12 and rear end cover 13 and other structures by means of threaded connection, alternatively, the connection between the pneumatic connector and the above-mentioned structures can also be achieved by means of snap connection or the like. Similar methods of connecting the pneumatic connector and the above-mentioned structures should be regarded as simple replacements.

[0059] Specifically, if Figure 3 As shown, the first air passage 21 is a cavity with an annular cross-section formed within the piston rod 2. A cone is provided at one end of the piston rod 2 within the cylinder body 1, and the first air passage 21 extends into this cone 23. The cone 23 is provided with a piston rod air outlet 231 axially arranged along the cone 23's radial direction and communicating with the first air passage 21. In an optional embodiment, there are two piston rod air outlets 231, the axes of which coincide and intersect perpendicularly with the axis of the cone.

[0060] Specifically, if Figure 3 As shown, the first pneumatic joint 24 is connected to the piston rod 2 by engaging with the threaded hole whose depth direction is radial direction of the piston rod 2 , and realizes the communication between the first pneumatic joint 24 and the first air channel 21 .

[0061] Specifically, if Figure 3 As shown, there are two first threaded holes 232 and the first threaded holes 232 are arranged on the end face of the cone 23 close to the rear end cover 13. Each first threaded hole 232 is connected to a piston air outlet and the depth direction of the first threaded hole 232 is perpendicular to the depth direction of the piston air outlet.

[0062] Specifically, if Figure 3 As shown, a cylindrical protrusion is further provided at the center position of the end surface of the cone 23 at the end of the piston rod 2 near the rear end cover 13, and a third threaded hole 233 is provided on the cylindrical protrusion, the depth direction of which is consistent with the axial direction of the piston rod 2. The third threaded hole 233 engages with the external thread on the floating joint 4, thereby fixing the floating joint 4 and the piston rod 2.

[0063] Specifically, if Figure 3 As shown, the piston rod 2 is further provided with a connecting end portion 22 at the center of the end surface outside the cylinder body 1. The connecting end portion 22 is cylindrical and can be set to a cylindrical shape, a triangular prism, a square prism, a hexagonal prism or other polygonal prism according to the specific application.

[0064] like Figure 1 、 Figure 3 and Figure 4As shown, in the air-floating frictionless cylinder provided in this embodiment, the connector 3 is integrally formed and includes a first rod portion 31, a step portion 32 and a second rod portion 33 arranged in sequence in the axial direction of the cylinder 11; the step portion 32 includes a first step portion 321 and a second step portion 322, the outer diameter of the first step portion 321 is smaller than the outer diameter of the second step portion 322, and the first step portion 321 is provided with an external thread so that the first step portion 321 is threadedly connected to the air-floating bearing 5.

[0065] Specifically, if Figure 4 As shown, the first step portion 321 and the second step portion 322 are both truncated cone-shaped, and the axis of the first step portion 321 and the axis of the second step portion 322 both coincide with the axis of the cylinder 11 .

[0066] Specifically, if Figure 4 As shown, the second threaded hole 3221 is located on the side of the second step portion 322 away from the rear end cover 13, and the number of the second threaded holes 3221 is two; a second air duct 323 is provided on the step portion 32, and the second air duct 323 is connected to a second threaded hole 3221, so that the second air duct 323 is connected to the first air duct 21; a third air duct 311 is provided on the first rod portion 31, extending into the step portion 32, and the third air duct 311 is connected to another second threaded hole 3221, so that the third air duct 311 is connected to the first air duct 21.

[0067] Specifically, if Figure 4 As shown, the second step portion 322 is provided with a first through hole 3222 and a second through hole 3224 with a depth direction that is radial to the second step portion 322. The first through hole 3222 is connected to one second threaded hole 3221 and to the second air passage 323. The second through hole 3224 is connected to another second threaded hole 3221 and to the third air passage 311. The depth of the first through hole 3222 is less than that of the second through hole 3224. The axis of the first through hole 3222 coincides with the axis of the second through hole 3224 and is perpendicular to the axis of the cylinder 11. The first plug 3223 is inserted into the first through hole 3222 to prevent gas from escaping from the first through hole 3222 via the second air passage 323 and out of the connector 3. The second plug 3225 is inserted into the second through hole 3224 to prevent gas from escaping from the second through hole 3224 via the third air passage 311 and out of the connector 3. The “through hole + plug” design can simplify the processing difficulty of the second air channel 323 and the third air channel 311.

[0068] Specifically, if Figure 4As shown, a first groove 3121 is provided on the end surface of the first step portion 321 near the rear end cover 13, and a first sealing ring 3122 is disposed within the first groove 3121. An annular boss 312 is provided on the end of the first rod portion 31 near the rear end cover 13, and a second groove 3226 is provided on the end surface of the annular boss 312 near the rear end cover 13, and a second sealing ring 3227 is disposed within the second groove 3226. After the connector 3 and the air bearing 5 are assembled, the first sealing ring 3122 and the second sealing ring 3227 enhance the airtightness within the air bearing 5, thereby more accurately controlling the air pressure within the cylinder 1 and the air bearing 5 for better servo control. The sealing effect of the first sealing ring 3122 and the second sealing ring 3227 will be described below in conjunction with the structure of the air bearing 5.

[0069] Specifically, if Figure 4 As shown, the end of the second rod portion 33 away from the first rod portion is the connector tail end 331, and the connector tail end 331 is a hexagonal prism or other polygonal body, of course, it can also be a cylinder; the connector tail end 331 is embedded in the floating joint 4 and can move radially along the cylinder 11 inside the floating joint 4.

[0070] like Figure 1 、 Figure 3 and Figure 5 As shown, in the air-floating frictionless cylinder provided by this embodiment, the air-floating bearing 5 is integrally formed and includes a bearing side wall 51, a bearing pressure-bearing avoidance near the rear end cover 13, and a bearing limiting wall 53 near the front end cover 12 and located in the air-floating bearing 51. The bearing side wall 51 and the bearing limiting wall 53 form a third cavity 54, and a fourth cavity 55 is formed on the bearing pressure-bearing wall 52. The inner cavity of the air-floating bearing 5 includes the third cavity 54 and the fourth cavity 55. The axes of the third cavity 54 and the fourth cavity 55 coincide with the axis of the cylinder 11; the throttle hole 511 is provided on the bearing side wall 51 and is connected to the third cavity 54. The side of the bearing pressure-bearing wall 52 is provided with a A first pressure relief groove 521 communicating with the fourth cavity 55 is provided. The first pressure relief groove 521 is annular and the center of the first pressure relief groove 521 is located on the axis of the cylinder 11; a fourth threaded hole 531 is provided on the bearing limiting wall 53, and the fourth threaded hole 531 engages with the external thread of the first step portion 321 of the connector 3 to fix the air bearing 5 and the connector 3; after the connector 3 and the air bearing 5 are assembled, the first sealing ring 3122 contacts the outer surface of the air bearing limiting wall 53, the second sealing ring 3227 contacts the inner surface of the bearing pressure wall 52, the third air channel 311 is communicated with the third cavity 54, and the fourth air channel 514 is communicated with the fourth cavity 55.

[0071] Specifically, during the operation of the cylinder, the bearing pressure-bearing wall 52 mainly bears the pressure between the rear end cover 13 in the cylinder 1 and the air bearing 5 .

[0072] Specifically, the external thread on the first step portion 321 engages with the fourth threaded hole 531 on the bearing limiting wall 53 to realize the assembly of the connector 3 and the air bearing 5. After the connector 3 and the air bearing 5 are assembled, the stepped boss 32 of the connector 3 is restricted in the limiting groove formed by the bearing outer wall 51 and the bearing limiting wall 53 and located on the outside of the air bearing, which helps to reduce the impact of the gas on the bearing limiting wall 52.

[0073] Specifically, the first sealing ring 3122 contacts the outer surface of the bearing limiting wall 53, specifically, the first sealing ring 3122 is tightly pressed against the outer surface of the bearing limiting wall 53 to prevent the gas in the third cavity 54 from leaking through the contact surface between the second step portion 322 of the connector and the bearing limiting wall 53.

[0074] Specifically, the second sealing ring 3227 contacts the inner surface of the bearing pressure wall 52, and specifically the second sealing ring 3227 is tightly pressed against the inner surface of the bearing pressure wall 52, so that the fourth channel is connected to the fourth cavity 55 and prevents the gas in the fourth cavity 55 from leaking through the contact surface between the annular boss 312 of the connector 3 and the bearing pressure wall 52.

[0075] In the air-floating frictionless cylinder provided in this embodiment, the air bearing 5 is designed based on the principle of a static pressure gas bearing. The anti-eccentricity capability of the air bearing 5, the leakage of the cylinder, and the stability of the operation of the air bearing 5 all depend on the characteristics of the air bearing 5. The leakage model and leakage flow of the air bearing 5 ultimately affect the pressure of the chambers on both sides of the air bearing 5 in the cylinder body 1, and are related to the servo control accuracy of the cylinder. Therefore, the constraint equation for the air film pressure between the air bearing 5 and the inner wall of the cylinder barrel 11 can be derived using the equation of motion, the continuity equation, and the gas state equation, namely the Reynolds equation for viscous compressible gas. After dimensionless conversion, the following equation is obtained:

[0076]

[0077] Where:

[0078]

[0079] Where R is the ideal gas constant, T is the absolute temperature, u, V, w are the gas particles at x,

[0080] -----The numerical components in the y and z directions, where x, z, h, p, t are the dimensionless forms of the variables x, z, h, p, 1, respectively, where h- represents the thickness of the air film, h0 is the width of the average gap between the air bearing 5 and the inner wall of the cylinder 11 in the radial direction of the cylinder 11, that is, h| ε＝0 .

[0081] Fluent software was used to optimize the structural dimensions of the air bearing 5. In the air-floating frictionless cylinder provided in this embodiment, a second pressure relief groove 515 is provided at the end of the air bearing 51 away from the pressure-bearing wall. This second pressure relief groove 525 is annular, with its center located on the axis of the cylinder barrel 11. The first and second pressure relief grooves 521 and 515 are connected by a fourth air passage 514 located within the sidewall. Specifically, radial blind holes 513 are provided within each of the first and second pressure relief grooves 521, 521, which serve to equalize pressure.

[0082] Specifically, the throttle holes 511 are arranged in three rows of six holes on the side wall of the air bearing 5. In some specific embodiments, the outer wall of the air bearing 5 is provided with pressure-equalizing grooves 512 corresponding one to each of the throttle holes 511. The pressure-equalizing grooves 512 are circular grooves, and the center of each pressure-equalizing groove 512 coincides with the center of a throttle hole 511. The pressure-equalizing grooves 512 further improve the uniformity of the air film formed between the air bearing 5 and the inner wall of the cylinder 11.

[0083] Since the air bearing 5 adopts three rows of six-hole throttle holes 511 and pressure relief grooves are set at the front and rear ends of the air bearing 5, the gas is evenly distributed in the bearing and excess gas pressure is released when necessary.

[0084] Please refer to Figures 1 to 5 , the piston motion of the air-floating frictionless cylinder provided in this embodiment is briefly described. Figure 1 Taking the direction in the figure as an example, the left side of the air bearing 5 is the left chamber, and the right side of the air bearing 5 is the right chamber.

[0085] The gas provided by the first pneumatic connector 24 enters the third cavity 54 in the air bearing 5 through the first air channel 21 and the second air channel 323 , and the gas at the first pressure of the first pneumatic connector 24 enters the fourth cavity 55 through the first air channel 21 and the third air channel 311 .

[0086] Specifically, the gas in the first chamber also escapes into the cylinder body 1 through the piston rod air outlet 231. The gas in the third chamber 54 escapes from the third chamber 54 through the throttle hole 511. The gas in the fourth chamber 55 escapes from the fourth chamber 55 through the first pressure relief groove 521. When the second pressure relief groove 515 is present, the gas in the fourth chamber 55 escapes through the fourth air passage 514 and out of the second pressure relief groove 521. The gas escaping from the throttle hole 511 and the pressure relief grooves forms a uniform air film between the air bearing 5 and the inner wall of the cylinder barrel 11. This air film provides support, thereby preventing contact between the air bearing 5 and the inner wall of the cylinder barrel 11, and effectively avoiding friction.

[0087] Specifically, by adjusting the air pressure of the first pneumatic joint 24 and the fourth pneumatic joint 132, the left-right movement of the air bearing 5 can be controlled. When the pressure in the left chamber is greater than that in the right chamber, the air bearing 5 moves rightward; when the pressure in the left chamber is less than that in the right chamber, the air bearing 5 moves leftward. The left-right movement of the air bearing 5 drives the piston rod 2. In specific applications, the movement of the piston rod 2 drives a power transmission structure such as a pulley, gear, rack, chain, or conveyor belt to operate the device. The two third pneumatic joints 234, symmetrically arranged on either side of the connector, connect the third and fourth cavities of the air bearing 5 to the first air channel 21 on the piston rod 2 and the high-pressure chamber in the cylinder body 1 through an air path. This ensures that the pressure inside the air bearing 5 cavity is always consistent with the pressure on the high-pressure chamber side of the cylinder (the right chamber with a higher pressure than the left chamber, or the left chamber with a higher pressure than the right chamber). This helps further improve the accuracy of pneumatic servo control.

[0088] It should be noted that, in the various technical solutions provided in this embodiment, descriptions such as "coinciding with the axis of the cylinder 11", "coinciding with the axial direction of the piston rod 2", "coinciding with the axial direction of the connector 3" and "coinciding with the axial direction of the front end cover 12" not only include the situation in the ideal state when the cylinder is in normal working condition, but also include the situation within the allowable error range in actual application.

[0089] Those skilled in the art will understand that the terms "first" and "second" are used for descriptive purposes only and should not be construed to indicate or imply relative importance or implicitly specify the number of the technical features indicated. Thus, a feature specified as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, unless otherwise specified, "plurality" means two or more.

[0090] In the description of this application, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to direct connections, indirect connections through an intermediate medium, or internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in this application based on the specific circumstances.

[0091] In the description of this specification, specific features, structures, materials or characteristics may be combined in an appropriate manner in any one or more embodiments or examples.

[0092] The above are only some of the implementation methods of the present application. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present application. These improvements and modifications should also be regarded as the scope of protection of the present application.

Claims

1. An air-floating frictionless cylinder, characterized in that: include: A cylinder body, comprising a cylinder barrel and a front end cover and a rear end cover fixed at both ends of the cylinder barrel; A motion assembly comprising an air bearing, a connector, a floating joint, and a piston rod, wherein the air bearing, the connector, the floating joint, and the piston rod are arranged in sequence in a direction from the rear end cover to the front end cover, the air bearing, the connector, and the floating joint are located within the cylinder, and the piston rod passes through the front end cover and is partially located within the cylinder; An air bearing, the air bearing being located in the front end cover and sleeved on the piston rod; The air bearing is fixedly connected to the first end of the connector, the second end of the connector is connected to the first end of the floating joint and can move radially within the floating joint along the cylinder, and the second end of the floating joint is fixedly connected to the piston rod; A first pneumatic joint is provided on the portion of the piston rod located outside the front end cover, a second pneumatic joint is provided on the end of the piston rod located in the cylinder, a third pneumatic joint is provided on the connector, and the first pneumatic joint is communicated with the second pneumatic joint, and the second pneumatic joint is communicated with the third pneumatic joint, so that the inner cavity of the air bearing is communicated with the first pneumatic joint, and a fourth pneumatic joint is provided on the rear end cover, and the fourth pneumatic joint is communicated with the inner cavity of the cylinder; The air bearing is provided with a throttle hole, and the gas in the air bearing is ejected through the throttle hole to form an air film between the air bearing and the inner wall of the cylinder; The front end cover is provided with a fifth pneumatic joint and a sixth pneumatic joint, and the fifth pneumatic joint and the sixth pneumatic joint form an air film between the air bearing and the inner wall of the front end cover.

2. The air-floating frictionless cylinder according to claim 1, characterized in that: The front end cover is penetrated by a stepped hole along the axial direction of the cylinder, and the stepped hole includes a first stepped hole and a second stepped hole located on the side of the first stepped hole away from the cylinder, the aperture of the first stepped hole is larger than the outer diameter of the piston rod, and the aperture of the second stepped hole is larger than the outer diameter of the air bearing.

3. The air-floating frictionless cylinder according to claim 2, characterized in that: The piston rod is provided with a first air channel and a first threaded hole, respectively. Two ends of the first air channel are connected to the first pneumatic joint and the first threaded hole respectively. The second pneumatic joint is engaged with the first threaded hole. The connector is provided with a second threaded hole, the third pneumatic joint is engaged with the second threaded hole, and the second pneumatic joint and the third pneumatic joint are connected through a hose; A truncated cone is provided at one end of the piston rod located in the cylinder body, and the first air channel extends into the truncated cone. A piston rod air outlet hole is provided on the truncated cone, which is axially arranged along the radial direction of the truncated cone and communicated with the first air channel.

4. The air-floating frictionless cylinder according to any one of claims 1 to 3, characterized in that: The connector is integrally formed and includes a first rod portion, a step portion, and a second rod portion arranged in sequence in the axial direction of the cylinder; The step portion includes a first step portion and a second step portion. The outer diameter of the first step portion is smaller than the outer diameter of the second step portion. The first step portion is provided with an external thread so that the first step portion is threadedly connected to the air bearing thread.

5. The air-floating frictionless cylinder according to claim 4, characterized in that: The second threaded holes are located on a side of the second step away from the rear end cover, and there are two second threaded holes; A second air passage is provided on the step portion, and the second air passage is communicated with one of the second threaded holes, so that the second air passage is communicated with the first air passage; The first rod portion is provided with a third air passage extending into the step portion, and the third air passage is communicated with another second threaded hole, so that the third air passage is communicated with the first air passage.

6. The air-floating frictionless cylinder according to claim 5, characterized in that: A first groove is provided on the end surface of the first step portion close to the rear end cover, and a first sealing ring is provided in the first groove; An annular boss is provided at one end of the first rod portion close to the rear end cover, a second groove is provided at the end surface of the annular boss close to the rear end cover, and a second sealing ring is provided in the second groove.

7. The air-floating frictionless cylinder according to claim 6, characterized in that: The air bearing is integrally formed and includes a bearing side wall, a bearing pressure-bearing wall close to the rear end cover, and a bearing limiting wall close to the front end cover. The bearing side wall and the bearing limiting wall form a third cavity, and a fourth cavity is formed on the bearing pressure-bearing wall. The inner cavity of the air bearing includes the third cavity and the fourth cavity, and the axes of the third cavity and the fourth cavity both coincide with the axis of the cylinder. The throttle hole is provided on the side wall of the bearing and is in communication with the third cavity. The side surface of the bearing pressure-bearing wall is provided with a first pressure relief groove in communication with the fourth cavity. The first pressure relief groove is annular and the center of the first pressure relief groove is located on the axis of the cylinder. A fourth threaded hole is provided on the bearing limiting wall, and the fourth threaded hole engages with the external thread of the first step portion of the connector so that the air bearing is fixedly connected to the connector. After the air bearing is assembled with the connector, the first sealing ring contacts the outer surface of the air bearing close to the bearing limiting wall, the second sealing ring contacts the inner surface of the bearing pressure wall, the third air duct is connected to the third cavity, the fourth air duct is located in the side wall of the air bearing, and the fourth air duct is connected to the fourth cavity.

8. The air-floating frictionless cylinder according to claim 7, characterized in that: A second pressure relief groove is provided on a side of the bearing side wall away from the bearing pressure bearing wall. The second pressure relief groove is annular and the center of the second pressure relief groove is located on the axis of the cylinder; The first pressure relief groove and the second pressure relief groove are communicated with each other through a fifth air passage located in the side wall of the bearing.

9. The air-floating frictionless cylinder according to claim 8, characterized in that: The throttle holes are distributed on the side wall of the bearing in a three-row, six-hole pattern.

10. The air-floating frictionless cylinder according to claim 9, characterized in that: The bearing side wall is provided with pressure equalizing grooves corresponding to the throttle holes one by one, and the pressure equalizing grooves are circular grooves, and the center of each pressure equalizing groove coincides with the center of one of the throttle holes.

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