A gas static pressure bearing

Abstract

The present invention discloses a gas static pressure bearing, which relates to the technical field of bearings. The gas static pressure bearing includes a bearing, a shaft neck matched with the bearing, and the bearing includes a body, and also includes: at least three pressure plates, the pressure plates are evenly spaced and arranged on the inner cylindrical surface of the body; an elastic film, the elastic film is arranged on the inner cylindrical surface of the body through the pressure plate; a cylindrical cavity, the cylindrical cavity is arranged between two adjacent pressure plates on the inner cylindrical surface of the body; the number of the cylindrical cavities corresponds to the number of pressure plates; a driving member, the driving member is arranged in the cylindrical cavity. The present invention acts on the thrust hemisphere through the elongation and contraction of the piezoelectric ceramic driver, promotes the radial movement of the film plane, and further drives the radial movement of the air cushion, thereby realizing active control of the size of the air cushion gap, thereby controlling the size of the air film pressure, which can be used to improve the rotation accuracy of the shaft neck, suppress the shaft neck vibration and actively control the axis trajectory.

Description

Technical Field

[0001] The invention relates to the technical field of bearings, and in particular to a gas static pressure bearing. Background Art

[0002] Hydrostatic bearings are a type of sliding bearings that use a pressure pump to force pressurized lubricants into the tiny gap between the bearing and the journal. According to the type of lubricant, they can be divided into two categories: liquid hydrostatic bearings, which mainly use oil as a lubricant; and gas hydrostatic bearings, which use gas as a lubricant, mainly air as a lubricant. Compared with liquid hydrostatic bearings, gas hydrostatic bearings have a series of advantages such as low friction loss, long life, high motion accuracy, and no pollution. They can be used in extreme working conditions, so they have broad application prospects.

[0003] The principle of static lubrication is different from that of dynamic lubrication. The static bearing uses an external lubricating oil pump to provide pressure oil to form a pressure oil film to bear the load. For gas static bearings, the use of external pressure gas supply is its basic working mode. The throttle is the key to its structure. The eccentricity caused by the deadweight and load of the spindle during operation establishes the corresponding bearing and stiffness machining center mechanism. Taking the radially supplied static air bearing as an example, the air flow channel of the radial hole static gas shaft is mainly composed of two parts: the throttle hole and the radial clearance of the bearing. The throttle hole is a device that produces a throttling effect before the external pressurized gas enters the bearing clearance, and forms a stable lubricating air film with a certain load-bearing capacity and stiffness. The bearing changes the radial clearance and adjusts the impedance to the air flow to change the air flow, thereby affecting the upstream flow conditions, changing the throttle hole outlet pressure, and establishing a new balance in the bearing cavity.

[0004] At present, some existing gas hydrostatic bearings have low rotation accuracy, and the journal is prone to vibration, resulting in the deviation of the axis trajectory. How to solve the above technical problems is a technical problem that needs to be solved in the current bearing technology field. Summary of the invention

[0005] In view of the above technical problems, an embodiment of the present invention provides a gas hydrostatic bearing to solve the problems raised in the above background technology.

[0006] The present invention provides the following technical solution: a gas static pressure bearing, comprising a bearing, a journal matched with the bearing, the bearing comprising a body, and further comprising:

[0007] At least three pressing plates, the pressing plates being evenly spaced and arranged on the inner cylindrical surface of the body;

[0008] An elastic film, the elastic film is surrounded by a pressing plate and arranged on the inner cylindrical surface of the main body;

[0009] A cylindrical cavity, wherein the cylindrical cavity is arranged between two adjacent pressing plates on the cylindrical surface of the body; the number of the cylindrical cavities corresponds to the number of pressing plates;

[0010] A driving member, wherein the driving member is disposed in the cylindrical cavity;

[0011] A push block, wherein the push block is disposed on the driving member, and the driving member and the elastic film are connected via the push block;

[0012] The air cushion is arranged on an elastic film, an air pressure cavity is opened on the air cushion, and an air cushion gap is formed between the arc surface of the air cushion and the shaft neck.

[0013] Preferably, the elastic film forms a film connection position at the pressure plate connection position, and forms a film plane between two adjacent pressure plates, and the air cushion is arranged on the film plane.

[0014] Preferably, the driving element is a piezoelectric ceramic driver.

[0015] Preferably, the push block is a thrust hemisphere.

[0016] Preferably, a threaded hole A is formed on the outer cylindrical surface of the main body at a position corresponding to the cylindrical cavity, and a bolt is arranged in the threaded hole A.

[0017] Preferably, the elastic film is connected to the air cushion via flexible hinges A and B.

[0018] Preferably, the pressure plate includes a pressure plate arm and two fixed ends, threaded holes B are formed on the fixed ends, and the pressure plate is connected to the annular groove A on the body by bolts.

[0019] Preferably, an annular groove B is formed on the outer cylindrical surface of the main body, and the annular groove B is used for assembling the bearing and the bearing seat.

[0020] Preferably, an air supply hole is provided at the end of the air cushion, a throttling hole is provided at the connection between the inside of the air cushion and the air pressure chamber, and the air supply hole and the throttling hole are connected via a vent hole.

[0021] An embodiment of the present invention provides a gas hydrostatic bearing, which has the following beneficial effects:

[0022] (1) The present invention acts on the thrust hemisphere through the extension and contraction of the piezoelectric ceramic driver, pushing the film plane to move radially, further driving the radial movement of the air cushion, and realizing active control of the size of the air cushion gap, thereby controlling the size of the air film pressure, which can be used to improve the rotation accuracy of the journal, suppress the journal vibration and actively control the axis trajectory;

[0023] (2) A flexible hinge is provided on the elastic film to further improve the sensitivity of the active control air cushion. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a schematic structural diagram of a gas static pressure bearing of the present invention;

[0025] Figure 2 A transverse cross-sectional view of a gas hydrostatic bearing of the present invention;

[0026] Figure 3 An axial view of a gas hydrostatic bearing of the present invention;

[0027] Figure 4 It is a schematic diagram of the structure of the air cushion of the present invention;

[0028] Figure 5 It is a structural schematic diagram of the pressing plate of the present invention;

[0029] In the figure, 1 is a bearing; 11 is a body; 111 is a threaded hole A; 112 is a cylindrical cavity; 113 is an annular groove A; 114 is annular groove B; 12 is an elastic film; 121 is a flexible hinge A; 122 is a flexible hinge B; 123 is a film plane; 124 is a film connection position; 13 is a pressure plate; 131 is a pressure plate arm; 132 is a fixed end; 133 is a threaded hole B; 14 is a thrust hemisphere; 15 is a piezoelectric ceramic driver; 16 is a bolt; 17 is an air cushion; 171 is an air supply hole; 172 is an air vent; 173 is a throttle hole; 174 is an air pressure cavity; 175 is a fixed plane; 176 is an arc surface; 177 is an air cushion gap; 2 is a journal. DETAILED DESCRIPTION

[0030] 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 those skilled in the art without creative work are within the scope of protection of the present invention.

[0031] See also Figure 1-Figure 5 , Figure 1 It is a schematic structural diagram of a gas static pressure bearing of the present invention; Figure 2 A transverse cross-sectional view of a gas hydrostatic bearing of the present invention; Figure 3 An axial view of a gas hydrostatic bearing of the present invention; Figure 4 It is a schematic diagram of the structure of the air cushion of the present invention; Figure 5 It is a schematic structural diagram of the pressing plate of the present invention.

[0032] A gas static pressure bearing comprises a bearing 1 and a journal 2 matched with the bearing 1. The bearing 1 comprises a body 11 and further comprises:

[0033] At least three pressing plates 13, the pressing plates 13 are evenly spaced and arranged on the inner cylindrical surface of the body 11;

[0034] An elastic film 12, wherein the elastic film 12 is surrounded by a pressing plate 13 and disposed on the inner cylindrical surface of the body 11, wherein the elastic film 12 forms a film connection position 124 at a connection position of the pressing plate 13, and forms a film plane 123 between two adjacent pressing plates 13;

[0035] A cylindrical cavity 112, wherein the cylindrical cavity 112 is disposed between two adjacent pressing plates 13 on the inner cylindrical surface of the body 11; the number of the cylindrical cavities 112 corresponds to the number of the pressing plates 13;

[0036] A driving member 15, wherein the driving member 15 is disposed in the cylindrical cavity 112;

[0037] A push block 14, wherein the push block 14 is disposed on the driving member 15, and the driving member 15 and the elastic film 12 are connected via the push block 14;

[0038] The air cushion 17 is arranged on the elastic film 12 , and an air pressure cavity 174 is opened on the air cushion 17 . An air cushion gap 177 is formed between the arc surface 176 of the air cushion 17 and the journal 2 .

[0039] Preferably, the driving member 15 is a piezoelectric ceramic driver.

[0040] Preferably, the push block 14 is a thrust hemisphere.

[0041] It should be noted that the contact between the thrust hemisphere and the film plane 123 is point contact. In actual operation, the contact point can be adaptively adjusted according to the applied load and processing and assembly errors. At the same time, the lateral friction between the thrust hemisphere and the film plane is greatly reduced.

[0042] Preferably, the elastic film 12 forms a film connection position 124 at the connection position of the pressing plate 13 , and forms a film plane 123 between two adjacent pressing plates 13 , and the air cushion 17 is arranged on the film plane 123 .

[0043] It should be noted that, in the embodiment of the present invention, five uniformly spaced pressure plates 13 are provided on the inner cylindrical surface of the main body 11, and after the elastic film 12 is fixed by the pressure plates 13, five film connection positions 124 and five film planes 123 are formed; five cylindrical cavities 112 are opened on the inner cylindrical surface of the main body 11, which are alternately and evenly arranged with the pressure plates 13, and a piezoelectric ceramic driver 15 is arranged in the cylindrical cavity 112; the piezoelectric ceramic driver 15 and the film plane 123 are connected by setting a thrust hemisphere 14.

[0044] The air cushion 17 comprises a fixing plane 175 and an arc surface 176 . The air cushion 17 is connected to the film plane 123 via the fixing plane 175 . The film plane 123 and the fixing plane 175 are connected by gluing or welding.

[0045] An air pressure cavity 174 is opened on the arc surface 176 of the air cushion 17, and an air cushion gap 177 is formed between the arc surface 176 of the air cushion 17 and the shaft neck 2. By controlling the extension or contraction of the piezoelectric ceramic driver 15 to drive the air cushion 17 to move radially, the size of the air cushion gap 177 can be actively controlled.

[0046] Furthermore, a threaded hole A111 is formed on the outer cylindrical surface of the body 11 at a position corresponding to the cylindrical cavity 112 , and a bolt 16 is arranged in the threaded hole A111 . The piezoelectric ceramic driver 15 can be replaced by removing the bolt 16 .

[0047] Furthermore, the elastic film 12 is connected to the air cushion 17 via the flexible hinge A121 and the flexible hinge B122. The deformation stiffness of the flexible hinge is extremely low, and the film is easily bent and deformed at the flexible hinge.

[0048] Furthermore, the pressure plate 13 includes a pressure plate arm 131 and two fixed ends 132, and a threaded hole B133 is formed on the fixed end 132. An annular groove A113 is formed at both ends of the main body 11, and a threaded hole C matching the threaded hole B133 is provided on the annular groove A113. The pressure plate 13 is connected to the annular groove A113 on the main body 11 by bolts.

[0049] Furthermore, an annular groove B114 is formed on the outer cylindrical surface of the body 11, and the annular groove B114 is used for assembling the bearing 1 and the bearing seat.

[0050] Furthermore, an air supply hole 171 is provided at the end of the air cushion 17 , a throttle hole 173 is provided at the connection between the inside of the air cushion 17 and the air pressure chamber 174 , and an air vent 172 is opened between the air supply hole 171 and the throttle hole 173 .

[0051] In the present invention, the gas flow path is: the gas enters through the air supply hole 171, flows through the vent hole 172, enters the air pressure chamber 174 through the throttle hole 173, and flows into the air cushion gap 177 between the arc surface 176 of the air cushion 17 and the shaft neck 2, establishing a static pressure air film on the mating surfaces of the bearing 1 and the shaft neck 2, reducing the friction between the bearing and the shaft neck.

[0052] The method of using a gas static pressure bearing of the present invention is as follows: when working, the piezoelectric ceramic driver 12 is extended and shortened to act on the thrust hemisphere 14, pushing the film plane 123 to move radially, further driving the air cushion 17 to move radially, and realizing active control of the size of the air cushion gap 177.

[0053] It should be noted that the rotation accuracy of the journal is often affected by the load and processing and assembly errors. In traditional bearings, the bearing capacity is affected by the throttling method, the air film thickness and the effective area of ​​the air pressure chamber. When the throttling method and the effective area of ​​the air pressure chamber are determined, the change in the air film thickness affects the static pressure of the air film, which also affects the rotation accuracy of the journal.

[0054] The gas hydrostatic bearing of the present invention can actively adjust the air cushion gap between the air cushion and the shaft neck, thereby actively changing the thrust of each air cushion on the shaft neck, pushing the shaft neck to move radially in the direction of reducing the motion error, thereby achieving the effect of improving the shaft neck rotation accuracy; based on this principle, it is also possible to achieve the effects of suppressing shaft neck vibration and actively controlling the axis trajectory.

[0055] A gas hydrostatic bearing provided by an embodiment of the present invention has the following beneficial effects: the present invention acts on the thrust hemisphere through the elongation and contraction of the piezoelectric ceramic driver, thereby promoting the radial movement of the film plane, further driving the radial movement of the air cushion, and realizing active control of the size of the air cushion gap, thereby controlling the size of the air film pressure, which can be used to improve the shaft neck rotation accuracy, suppress shaft neck vibration and actively control the axis trajectory; a flexible hinge is provided on the elastic film, which can further improve the sensitivity of the active control of the air cushion.

[0056] The device embodiments described above are merely illustrative, wherein the units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0057] In the present invention, unless otherwise clearly stipulated and limited, the terms such as "installation", "setting", "connection", "fixation" and "screw-on" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. Unless otherwise clearly defined, for ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances.

[0058] It is understandable that those skilled in the art can make equivalent substitutions or changes based on the technical solution and concept of the present invention, and all these changes or substitutions should fall within the protection scope of the claims attached to the present invention.

Claims

1. A gas hydrostatic bearing, comprising a bearing (1), a journal (2) matched with the bearing (1), wherein the bearing (1) comprises a body (11), characterized in that: Also includes: At least three pressing plates (13), wherein the pressing plates (13) are evenly spaced and arranged on the inner cylindrical surface of the body (11); An elastic film (12), wherein the elastic film (12) is disposed on the inner cylindrical surface of the body (11) by surrounding the pressing plate (13), a film connection position (124) is formed at the connection position of the pressing plate (13), and a film plane (123) is formed between two adjacent pressing plates (13); A cylindrical cavity (112), wherein the cylindrical cavity (112) is disposed between two adjacent pressing plates (13) on the inner cylindrical surface of the body (11); the number of the cylindrical cavities (112) corresponds to the number of the pressing plates (13); A driving member (15), wherein the driving member (15) is a piezoelectric ceramic driver and is disposed in the cylindrical cavity (112); A push block (14), wherein the push block (14) is disposed on the driving member (15), and the driving member (15) and the elastic film (12) are connected via the push block (14); An air cushion (17), wherein the air cushion (17) is arranged on the elastic film (12), an air pressure cavity (174) is opened on the air cushion (17), and an air cushion gap (177) is formed between the arc surface (176) of the air cushion (17) and the shaft neck (2); The elastic film (12) is connected to the air cushion (17) via a flexible hinge A (121) and a flexible hinge B (122).

2. A gas hydrostatic bearing according to claim 1, characterized in that the thrust block (14) is a thrust hemisphere.

3. A gas hydrostatic bearing according to claim 1, characterized in that a threaded hole A (111) is opened on the outer cylindrical surface of the body (11) at a position corresponding to the cylindrical cavity (112), and a bolt (16) is arranged in the threaded hole A (111).

4. A gas hydrostatic bearing according to claim 1, characterized in that the pressure plate (13) includes a pressure plate arm (131) and two fixed ends (132), a threaded hole B (133) is opened on the fixed end (132), and the pressure plate (13) is connected to the annular groove A (113) on the body (11) by bolts.

5. A gas hydrostatic bearing according to claim 1, characterized in that an annular groove B (114) is formed on the outer cylindrical surface of the body (11), and the annular groove B (114) is used for assembling the bearing (1) and the bearing seat.

6. A gas hydrostatic bearing according to claim 1, characterized in that an air supply hole (171) is provided at the end of the air cushion (17), a throttle hole (173) is provided at the connection between the inside of the air cushion (17) and the air pressure chamber (174), and the air supply hole (171) and the throttle hole (173) are connected via a vent hole (172).

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