Loading mechanism of non-contact plane air bearing test bench

Abstract

The present invention discloses a non-contact planar air-floating bearing test bench loading mechanism. The test bench loading mechanism mainly consists of an upper pressure head and a lower positive pressure loading module mounted on the upper end surface of the planar air-floating bearing to be tested, and the two are connected by a ball bearing. The pressure head includes a loading bolt, a handwheel mounted on the loading bolt, and a fixed frame; the positive pressure loading module includes a positive pressure air inlet, a positive pressure cavity, and an elastic foil; the positive pressure loading module introduces high-pressure gas through the positive pressure air inlet to load the planar air-floating bearing to be tested; during testing, an air film is formed between the positive pressure loading module and the upper surface of the planar air-floating bearing, and a loading force is applied to the planar air-floating bearing to be tested through the air film. There is a certain gap between the two relative active surfaces, which is non-contact loading. The test bench loading mechanism of the present invention has no contact with the planar air-floating bearing to be tested during loading, dynamic detection is performed, and operation is convenient.

Description

Technical Field

[0001] The invention relates to the field of plane air bearing performance testing, in particular to a non-contact plane air bearing test bench loading mechanism. Background Art

[0002] Ultra-precision air-floating motion platforms utilize planar air bearings to eliminate friction and mechanical creep between moving pairs, enabling ultra-precision positioning of parts, specimens, and other objects. These platforms are widely used in fields such as photolithography, CNC machining, biotechnology, and micro-measurement. Planar air bearings introduce high-pressure gas into the gap between relatively moving objects, forming an air film. This air film pressure provides load-bearing capacity, eliminating direct contact friction between moving pairs and providing both support and lubrication.

[0003] Performance testing of planar air bearings requires high precision, generally requiring high loading accuracy, no additional torque, and no impact on the bearing's motion. Traditional loading mechanisms often have a certain degree of rigidity. When the air film thickness of the bearing under test changes, the loading surface undergoes slight displacement along the loading direction, resulting in significant variations in the loading force. Furthermore, traditional loading mechanisms struggle to provide controllable, high-precision loading forces within typical machining accuracy. Summary of the Invention

[0004] In order to solve the problems of the inability of existing technologies to load planar air bearings and unbalanced loading, the present invention proposes a non-contact planar air bearing test bench loading mechanism, which can detect the load-bearing capacity and air film thickness of the planar air bearing under different air supply pressures and different loads. It is of great significance to the optimal design and theoretical analysis of the structural parameters of the planar air bearing and to improve the performance of the planar air bearing.

[0005] The present invention employs a technical solution to the loading problem, comprising a non-contact planar air bearing test bench loading mechanism, wherein the planar air bearing test bench primarily comprises a marble tabletop 10, a loading mechanism, an equipment stand, a micrometer, a pressure regulating valve, and an air compressor. The test bench loading mechanism primarily comprises an upper pressure head and a lower positive pressure loading module mounted on the upper end face of the planar air bearing being tested, the two connected by a ball bearing. The pressure head includes a loading bolt, a loading handwheel mounted on the loading bolt, and a fixed frame; the positive pressure loading module includes a positive pressure air inlet, a positive pressure cavity, and an elastic foil. High-pressure gas is introduced into the planar air bearing being tested through the high-pressure air supply port, and the positive pressure loading module introduces high-pressure gas through the positive pressure air inlet to load the planar air bearing being tested.

[0006] The positive pressure loading module is controlled to move up or down by rotating the loading hand wheel. The loading bolt adopts fine thread, which makes the movement of the positive pressure loading module more accurate.

[0007] During the test, an air film is generated between the positive pressure loading module and the plane air bearing being tested, and a loading force is applied to the plane air bearing being tested through the air film. There is a certain gap between the two relative moving surfaces, and there is no direct contact.

[0008] The loading force is applied to the air bearing of the measured plane through the air film, so the applied force is uniform and no eccentric and tilting torque is generated on the air bearing of the measured plane.

[0009] Minor errors are inevitable in the loading mechanism during the processing and assembly of various parts. The loading force is applied to the air bearing of the measured plane through the air film. This is a non-contact loading method. The magnitude of the loading force is determined by the air supply pressure, ensuring that the loading accuracy will not be affected by errors in the processing and assembly of parts during the test.

[0010] Four elastic foils are installed beneath the positive pressure chamber, laser spot-welded to the chamber at a 30° angle. During loading, the gap between the active surface of the positive pressure chamber and the measured plane's air bearing is 0.1 to 0.5 mm, achieving a contactless seal with the elastic foils. Pressure elastically deforms the foils, creating a micron-level clearance between the upper surface of the measured plane's air bearing.

[0011] A chamber for storing high-pressure gas is formed between the lower surface of the positive pressure cavity and the air bearing of the plane to be measured, and a loading force is provided to the air bearing of the plane to be measured through the gas pressure.

[0012] Compared with the prior art, the present invention has the following advantages:

[0013] 1. The positive pressure loading module and the plane air bearing to be tested are loaded through an air film with a certain gap, which is non-direct contact. This ensures that the plane air bearing to be tested is not subjected to any additional force during the test, and the loading force is more uniform, making the loading accuracy higher. This solves the problems of small loading range and large error in existing loading mechanisms.

[0014] 2. In the present invention, four elastic foils are installed below the positive pressure cavity and connected to the positive pressure cavity by laser spot welding at an angle of 30°. During testing, the elastic foils will deform under the action of pressure, resulting in a micron-level gap between the elastic foils and the upper surface of the plane air bearing being tested, which improves loading accuracy.

[0015] 3. Because the air film thickness at the elastic foil is micron-level, the flow loss of high-pressure gas from the gas source to the positive pressure chamber is much smaller than the flow loss near the elastic foil. The pressure within the positive pressure chamber is approximately equal to the supply pressure. Therefore, the loading force is proportional to the supply pressure. This loading mechanism can maintain a constant loading force when the measured planar air bearing experiences micron-level vibrations along the loading direction.

[0016] 4. Minor errors are inevitable during the manufacturing and assembly of the loading mechanism. Since the air film thickness of the plane air bearing being tested is on the micron level, even small manufacturing errors can significantly impact the film thickness. In the present invention, the loading bolt is connected to the loading module via a ball bearing. This allows for adjustment of the angle between the positive pressure loading module and the plane air bearing being tested, ensuring that the plane air bearing being tested and the loading module remain relatively parallel during testing. The applied loading force does not produce eccentric or tilting moments on the plane air bearing being tested.

[0017] In order to make the above and other objects, features and advantages of the present invention more obvious and easy to understand, preferred embodiments are given below and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0019] Figure 1 A side view of a loading mechanism in an embodiment of the present invention;

[0020] Figure 2 Schematic diagram of a loading mechanism in an embodiment of the present invention;

[0021] FIG3( a ) is a front view of a positive pressure loading module according to an embodiment of the present invention;

[0022] FIG3( b ) is a cross-sectional view taken along line AA in FIG3( a );

[0023] FIG3( c ) is a top view of the positive pressure loading module according to an embodiment of the present invention;

[0024] FIG3( d ) is a bottom view of the positive pressure loading module according to an embodiment of the present invention;

[0025] Figure 4 This is a schematic diagram of official road connections in an embodiment of the present invention;

[0026] Figure 5 Graph showing the linear relationship between gas supply pressure and loading force in an embodiment of the present invention.

[0027] The figure marks in the above drawings are: 1. loading handwheel; 2. loading bolt; 3. fixing frame; 4. ball head bearing; 5. positive pressure cavity; 6. positive pressure air inlet; 7. elastic foil; 8. air bearing of the measured plane; 9. high-pressure air supply port; 10. marble countertop. DETAILED DESCRIPTION

[0028] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. 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 making creative efforts are within the scope of protection of the present invention.

[0029] Example 1: See Figure 1-3(d) The figure shows a loading mechanism for a non-contact planar air bearing test bench. The test bench loading mechanism primarily consists of an upper pressure head and a lower positive pressure loading module mounted on the upper end face of the planar air bearing 8 being tested. The two are connected by a ball bearing 4. The pressure head includes a loading bolt 2, a loading handwheel 1 mounted on the loading bolt 2, and a fixed frame 3. The positive pressure loading module includes a positive pressure air inlet 6, a positive pressure cavity 5, and an elastic foil 7. High-pressure gas is introduced into the planar air bearing 8 being tested through a high-pressure air supply port 9. The positive pressure loading module then introduces high-pressure gas through the positive pressure air inlet 6 to load the planar air bearing 8 being tested.

[0030] The positive pressure loading module is controlled to move upward or downward by rotating the loading hand wheel 1, and the loading bolt 2 adopts a fine thread, which makes the control of the movement of the positive pressure loading module more accurate.

[0031] During the test, an air film is generated between the positive pressure loading module and the plane air bearing 8 to be tested, and a loading force is applied to the plane air bearing 8 to be tested through the air film. There is a certain gap between the two relative moving surfaces, and there is no direct contact.

[0032] The loading force is applied to the air bearing 8 of the measured plane through the air film, so the applied force is uniform and no eccentric and tilting moment is generated on the air bearing 8 of the measured plane.

[0033] Minor errors are inevitable in the loading mechanism during the processing and assembly of various parts. The loading force is applied to the air bearing 8 of the measured plane through the air film. This is a non-contact loading method. The magnitude of the loading force is determined by the air supply pressure, ensuring that the loading accuracy will not be affected by errors in the processing and assembly of parts during the test.

[0034] Four elastic foils 7 are installed beneath the positive pressure chamber 5, laser spot-welded at a 30° angle. During loading, the clearance between the active surfaces of the positive pressure chamber 5 and the measured plane's air bearing 8 is 0.1 to 0.5 mm. The elastic foils 7 achieve a non-contact seal. Under pressure, the elastic foils 7 elastically deform, maintaining a micron-level clearance between the upper surface of the measured plane's air bearing 8.

[0035] A chamber for storing high-pressure gas is formed between the lower surface of the positive pressure cavity 5 and the air bearing 8 of the measured plane, and a loading force is provided to the air bearing 8 of the measured plane through the gas pressure.

[0036] During the test, install pneumatic quick connectors at the positive pressure air inlet 6 of the positive pressure chamber 5 and the high pressure air supply port 9 of the tested plane air bearing 8, and connect them to the air compressor using pneumatic tubes and pressure regulating valves, respectively. Figure 4 After connecting the pipes, proceed with the following steps:

[0037] 1. Start the second pressure regulating valve to make the air bearing 8 of the measured plane start working;

[0038] 2. Control the movement of the loading bolt 2 by means of the loading handwheel 1 on the loading bolt 2. Turn the loading handwheel 1 to move the loading bolt 2 downward until the elastic foil 7 contacts the upper wall surface of the air bearing 8 of the plane being measured, causing the elastic foil 7 to deform.

[0039] 3. Open the first pressure regulating valve, the pressure in the positive pressure cavity 5 increases, and the elastic foil 7 further deforms under the pressure, resulting in a micrometer-level gap between the elastic foil 7 and the upper surface of the measured plane air bearing 8.

[0040] Because the air film thickness at the elastic foil 7 is micrometer-level, the flow loss of high-pressure gas from the gas source to the positive-pressure chamber 5 is much smaller than the flow loss near the elastic foil 7. The pressure within the positive-pressure chamber 5 is approximately equal to the supply pressure. Therefore, the loading force is proportional to the supply pressure. This loading mechanism can maintain a constant loading force when the measured plane air bearing 8 experiences micrometer-level vibrations along the loading direction.

[0041] According to the test requirements, the first pressure regulating valve is used to adjust the air supply pressure in the positive pressure cavity 5, that is, to adjust the loading force, and the second pressure regulating valve is used to adjust the working pressure of the plane air bearing 8 to be tested.

[0042] Taking the experimental parameters as an example, the working pressure range of the air compressor used is 0-0.8MPa, the size of the positive pressure chamber 5 is 0.2×0.2m, and the internal size of the positive pressure chamber 5 is 0.17×0.17m. Under this condition, the linear relationship between the air supply pressure and the loading force of the positive pressure loading module is as follows: Figure 5 shown.

[0043] Specific embodiments are used in the present invention to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core ideas. At the same time, for those skilled in the art, according to the ideas of the present invention, there may be changes in the specific implementation methods and application scopes. In summary, the contents of this specification should not be understood as limiting the present invention.

Claims

1. A non-contact plane air bearing test bench loading mechanism, characterized in that: include: The test bench loading mechanism mainly consists of an upper pressure head and a lower positive pressure loading module mounted on the upper end surface of the measured plane air bearing (8), the two being connected by a ball bearing (4); the pressure head includes a loading bolt (2), a loading handwheel (1), and a fixed frame (3); The positive pressure loading module comprises a positive pressure air inlet (6), a positive pressure cavity (5), and an elastic foil (7); The lower surface of the positive pressure cavity (5) has a cavity with a depth of millimeters; Four pieces of the elastic foil (7) are installed around the cavity on the lower surface of the positive pressure cavity (5), and are connected to the positive pressure cavity (5) by laser spot welding at an angle of 30 degrees; After high-pressure gas is introduced through the positive-pressure air inlet (6), the elastic foil (7) is deformed under the action of the pressure, so that a micrometer-level gap is formed between the elastic foil (7) and the upper surface of the measured plane air bearing (8); The positive pressure loading module introduces high-pressure gas through the positive pressure air inlet (6) to load the plane air bearing (8) to be measured.

2. The non-contact plane air bearing test bench loading mechanism according to claim 1, characterized in that: During testing, an air film is formed between the positive pressure loading module and the upper surface of the plane air bearing (8) to be tested, and a loading force is applied to the plane air bearing (8) to be tested through the air film, with a certain gap between the two relative active surfaces.

3. The non-contact plane air bearing test bench loading mechanism according to claim 1, characterized in that: After ventilation, the parallelism error between the positive pressure cavity (5) and the measured plane air bearing (8) is automatically compensated through the ball head bearing (4).

4. The non-contact planar air bearing test bench loading mechanism according to claim 1, characterized in that: During the test, the positive pressure loading module is controlled to move upward or downward by rotating the loading hand wheel (1). The loading bolt adopts a fine thread, which makes the control of the movement of the positive pressure loading module more accurate.

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