A gas suspension bearing

Abstract

This invention discloses a gas suspension bearing, which supports an object through the coupling effect of extruded gas and synthetic jet gas. The specific effects are as follows: 1. The upper metal membrane (2) vibrates at high frequency, extruding the gas membrane between itself and the load (9). When vibrating upwards, a high-pressure gas membrane is formed, which is positive extrusion; when vibrating downwards, the gas membrane pressure decreases, which is negative extrusion. The alternating extrusion process does work on the gas, increasing its energy and generating suspension force. 2. The lower metal membrane (4) vibrates at high frequency. When vibrating upwards, the cavity volume decreases, blowing out gas and generating thrust on the supported object (9); when vibrating downwards, the gas around the hole (8) is drawn into the cavity, generating suction, but the average force throughout the cycle remains a positive thrust. 3. By controlling the excitation signal, the metal membranes (2) and (4) compensate for each other's negative effects with their respective positive effects, allowing the bearing to continuously possess positive suspension force throughout the entire cycle, making the average suspension force of the entire bearing significantly higher than that of a single suspension method.

Description

Technical Field

[0001] This invention relates to active flow control technology and near-field ultrasonic extrusion gas suspension, specifically to a gas suspension bearing that couples near-field ultrasonic extrusion suspension with synthetic jet suspension to achieve a large and stable suspension force in a highly efficient and simple manner. Background Technology

[0002] Near-field ultrasonic extrusion levitation technology, as a non-contact technology, boasts advantages such as compact structure, strong controllability, and no limitation on the material of the suspended object. Its applications span biological, chemical, rotating machinery, and microelectromechanical systems (MEMS), attracting increasing attention from researchers. Its levitation force is obtained by averaging the positive and negative extrusion forces generated by the up-and-down vibration of the oscillator within one cycle. Because the negative extrusion force weakens the positive extrusion force, its overall average levitation force is relatively small, limiting its application.

[0003] Synthetic jets, with their simple and compact structure and pollution-free operation, are a flow control technology. They are widely used in flow separation and aerodynamic control, jet vector control, enhanced mixing and heat transfer control, noise suppression, microfluidic control, flight control, particle dispersion control, and synthetic jet gyroscope technology. However, synthetic jet technology has not yet been applied to non-contact levitation. Because synthetic jets periodically draw in and expel gas, if applied to levitation, the resulting thrust would involve alternating positive and negative forces, and while the resulting levitation force has not been extensively studied, it is generally not very large. Summary of the Invention

[0004] To overcome the problem that both extruded gas and synthetic jet gas have relatively low load-bearing capacity when applied to gas bearings, this invention proposes a gas suspension bearing.

[0005] The technical solution of the present invention is as follows:

[0006] The present invention discloses a gas suspension bearing, characterized in that the gas suspension bearing comprises an ultrasonically extruded metal film, an excitation unit, and a synthetic jet exciter, and the actions of these two parts are coupled to achieve a large stable suspension force in a highly efficient and simple manner.

[0007] The upper metal membrane undergoes simple harmonic vibrations at a certain frequency. During upward vibration, the space between the metal membrane and the supported object decreases, compressing the gas within and forming a high-pressure gas film—this is positive compression. During downward vibration, the space between the metal membrane and the supported object increases, the gas within the space becomes rarefied, and the gas film pressure decreases—this is negative compression. The alternation of positive and negative compression within one cycle of membrane vibration does work on the gas, increasing its energy and generating levitation force.

[0008] The lower metal membrane undergoes simple harmonic vibrations at a certain frequency. When the metal membrane vibrates upward, the cavity volume decreases, expelling gas and generating thrust to support the supported object; when it vibrates downward, gas around the hole is drawn into the cavity, generating suction. However, throughout the entire cycle, due to the effect of the metal membrane on the gas, the average force generated by the combined jet is still thrust.

[0009] By controlling the excitation electrical signal, the upper and lower metal films are made to vibrate in opposite phases, thus creating a coupling effect. When the upper metal film vibrates upward, the lower metal film vibrates downward. The positive compression compensates for the suction force of the synthetic jet, keeping the object suspended. When the upper metal film vibrates downward, the lower metal film vibrates upward. The negative compression is compensated for by the thrust of the synthetic jet, generating a levitation force. In other words, a positive force is generated throughout the entire vibration cycle. Because the two metal films vibrate in opposite directions, the change in cavity volume is increased, which can also make the synthetic jet generate a greater positive force.

[0010] The excitation unit is installed on the modal nodes of the upper and lower metal films respectively, and uses the resonant frequency of the metal film as the working frequency to enable the film to obtain the maximum amplitude, making the film squeeze the gas more effectively, increasing the change in cavity volume, and ultimately obtaining a greater coupling levitation force.

[0011] The excitation unit can be ring-shaped, square, or similar, and is used to drive the metal film to vibrate up and down after an excitation electrical signal is applied.

[0012] The upper metal film needs to be installed on top of the gas suspension bearing and be able to vibrate up and down in a controllable high frequency to generate a squeezing and levitation effect.

[0013] The lower metal film needs to be installed at the bottom of the bearing to seal the cavity and perform controllable high-frequency up-and-down vibration, thereby changing the volume of the cavity to the greatest extent to enhance the levitation force of the synthetic jet.

[0014] The cylinder cavity can be in various shapes such as cylindrical, frustum, or square, and it has a gas storage function.

[0015] The airflow hole must be located on the axis of the cavity and can be a circular orifice or a slit orifice, etc. It is only used to uniformly draw in and eject gas into the cavity when generating the synthetic jet suspension effect.

[0016] The airflow holes can be arrayed in multiple arrays on the metal film, and the center of the array must still be located on the cavity axis to generate a synthetic jet suspension effect with a larger range of action.

[0017] The beneficial effect of this invention is that the gas suspension bearing of this invention uses the positive effects of near-field ultrasonic extrusion suspension and synthetic jet suspension to compensate for the negative effects of each other, so that the bearing has a continuous positive suspension force throughout the entire cycle, making the average suspension force of the entire bearing significantly higher than that of a single suspension method. This achieves the coupling effect of near-field ultrasonic extrusion and synthetic jet suspension, and ultimately enables the bearing to obtain a large and stable suspension force in a highly efficient and simple way. Attached Figure Description

[0018] Figure 1 This is an external view of a gas suspension bearing according to the present invention;

[0019] Figure 2 This is a schematic diagram of the overall structure of a gas suspension bearing according to the present invention, wherein 1 is the cylinder head, 2 is the upper metal film, 3 is the cylinder shell, 4 is the lower metal film, 5 is the upper excitation unit, 6 is the cavity, 7 is the lower excitation unit, 8 is the airflow hole, and 9 is the supported object.

[0020] Figure 3 This is a top view of a gas suspension bearing according to the present invention, wherein 8 is an airflow hole located at the center of the top of the component for ejecting a jet.

[0021] Figure 4 This is a schematic diagram of the overall structure of a gas suspension bearing with piezoelectric deformation of cylinder housing according to the present invention. 1 is the cylinder head, 2 is a metal film, 3 is the cylinder housing, which is a stacked annular piezoelectric sheet that performs telescopic vibration after receiving an electrical signal, 4 is the cylinder bottom, 5 is the excitation unit, 6 is the cavity, 7 is the load-bearing object, and 8 is the airflow hole.

[0022] Figure 5 This is a schematic diagram of the overall structure of a gas suspension bearing with piezoelectric deformation of cylinder housing according to the present invention. 1 is the cylinder head, 2 is the airflow hole, 3 is the cylinder housing, which is a stacked annular piezoelectric sheet that vibrates after an electrical signal is input, 4 is the cavity, 5 is the cylinder bottom, and 6 is the load-bearing object. Detailed Implementation

[0023] The present invention will now be described in further detail with reference to the accompanying drawings.

[0024] Example 1

[0025] Figure 1 This is an external view of Embodiment 1 of the present invention. Figure 2 This is a schematic diagram of the overall structure of Embodiment 1 of the present invention. The present invention controls the input signals of the upper and lower excitation units (5) and (7) to make the upper and lower metal films (2) and (4) vibrate in opposite directions.

[0026] During operation, the cylinder top cover (1) remains fixed.

[0027] When the upper metal film (2) vibrates upward, it generates a positive force for compression and suspension, and at the same time increases the volume of the cavity (3). At this time, the lower metal film (4) vibrates downward, the volume of the cavity (3) increases, the cavity (3) draws in more gas, and the positive force of compression compensates for the suction of the synthetic jet, generating a levitation force to support the object (9). When the upper metal film (2) vibrates downward, it generates a negative extrusion force, and at the same time decreases the volume of the cavity (3), compressing the gas in the cavity. At this time, the lower metal film (4) vibrates upward, causing the gas in the cavity to be further compressed. The compressed gas in the cavity is ejected to form a synthetic jet. The thrust of the synthetic jet compensates for the negative force of compression, thereby generating a levitation force to support the object (9). During the entire vibration cycle, the volume change of the cavity (3) increases, and the thrust of the synthetic jet also increases. The positive effects of compression and synthetic jet compensate for the negative effects of each other, so that the bearing has a continuous positive levitation force throughout the entire cycle, making the average levitation force of the entire bearing significantly higher than that of a single levitation method.

[0028] Example 2

[0029] Figure 4 This is a schematic diagram of the overall structure of this embodiment. The basic structure of this embodiment is the same as that of embodiment 1, with the upper structure remaining unchanged. The difference is that in this embodiment, the lower metal film (4) only serves a sealing function. The cylinder shell (3) is replaced with a stacked annular piezoelectric sheet, which causes the cylinder shell (3) to vibrate in an up-and-down extension manner after an excitation signal is input.

[0030] During operation, the cylinder top cover (1) remains fixed.

[0031] The top metal film (2) continues to vibrate up and down. When it vibrates upward, it generates a positive force for compression and suspension, while increasing the volume of the cavity (6). The cylinder shell (3) elongates under the excitation signal, further increasing the volume of the cavity (6). The cavity (6) draws in more gas, and the positive force of compression compensates for the suction of the synthetic jet, generating a levitation force to support the object (7). When the metal film (2) vibrates downward, it generates a negative extrusion force, while decreasing the volume of the cavity (6) and compressing the gas inside the cavity. At this time, the cylinder shell (3) shortens under the excitation signal, further compressing the gas inside the cavity. The compressed gas inside the cavity (6) is ejected to form a synthetic jet. The thrust of the synthetic jet compensates for the negative force of compression, thereby generating a levitation force to support the object (7). Throughout the entire vibration cycle, the volume change of the cavity (6) increases, and the thrust of the synthetic jet also increases. The positive effects of compression and synthetic jet compensate for the negative effects of each other, allowing the bearing to continuously have a positive levitation force throughout the entire cycle, making the average levitation force of the entire bearing significantly higher than that of a single levitation method.

[0032] Example 3

[0033] Figure 5This is a schematic diagram of the overall structure of this embodiment. In this embodiment, the vibration of the metal film at the top and bottom of the cylinder is eliminated, and the cylinder head (1) is enlarged. A stacked annular piezoelectric sheet is selected as the cylinder shell (3), so that the cylinder shell (3) vibrates up and down.

[0034] The bottom (5) of the cylinder is sealed during operation.

[0035] When the entire component is working, only the cylinder wall (3) vibrates due to the power supply. When the cylinder wall (3) extends, it drives the top cylinder head (1) to squeeze the air upward, generating a positive squeezing force. At the same time, the volume of the cavity (4) also increases, and the cavity (4) draws in gas, generating the suction force of the composite jet. At this time, the positive squeezing force compensates for the suction force of the composite jet in the cavity (4), generating a levitation force to support the object (6). When the cylinder wall (3) shortens, the top cylinder head (1) vibrates downward, generating a negative squeezing force. At the same time, the volume of the cavity (4) also decreases, and the compressed gas in the cavity (4) is ejected to form a composite jet. The thrust of the composite jet compensates for the negative squeezing force, thereby generating a levitation force to support the object (6). During the entire vibration cycle, due to the increase in the size of the cylinder head (1), its squeezing and levitation effect will be enhanced, and the positive effects of squeezing and composite jet will compensate for the negative effects of each other, allowing the bearing to continuously have a positive levitation force throughout the entire cycle, making the average levitation force of the entire bearing significantly higher than that of a single levitation method.

[0036] This invention is not limited to the optional embodiments described above. The specific embodiments described above are merely illustrative and instructive, and not restrictive. Those skilled in the art, guided by this specification and without departing from the scope of the claims, can create various forms of products, all of which are protected by this invention.

Claims

1. A gas levitation bearing, characterized by: The application relates to a gas suspension bearing, which comprises a first metal film (2) and a first exciting unit (5) containing near-field ultrasonic extrusion suspension, a cylinder cover (1), a cylinder shell (3), a second metal film (4), a cylinder cavity (6) and a second exciting unit (7) containing synthetic jet action; the cylinder cover (1) is provided with a hole in the center, and the first metal film (2) is arranged in the center; the first metal film (2) is provided with an airflow hole (8); the bottom of the cylinder shell (3) is provided with the second metal film (4) for sealing the lower end of the cylinder cavity (6); the first metal film (2) and the second metal film (4) are respectively provided with the first exciting unit (5) and the second exciting unit (7); the first exciting unit (5) and the second exciting unit (7) need to be connected with simple harmonic electric signals with a phase difference of 180 degrees, so that the first metal film (2) and the second metal film (4) have opposite up-down vibrations; when the first metal film (2) vibrates upwards, a positive extrusion effect is generated, so that objects are suspended; meanwhile, the second metal film (4) vibrates downwards to increase the volume of the cylinder cavity, so that the cylinder cavity inhales air; the high-pressure extruded gas generated by the positive extrusion compensates the inhaling effect of the synthetic jet; when the first metal film (2) vibrates downwards, a negative extrusion effect is generated; the second metal film (4) vibrates upwards to reduce the volume of the cylinder cavity, so that a jet is generated to form a thrust; the negative extrusion is compensated under the thrust of the synthetic jet, so that the negative extrusion process is weakened; during the opposite vibration process, the volume change amount is increased, the synthetic jet generates a greater positive force, and the suspension force of the synthetic jet is enhanced under the compensation of the extrusion effect; finally, the positive effect of the extrusion and the synthetic jet is used to compensate the negative effect of the other one, so that the bearing continuously has a positive suspension force in the whole cycle, the average suspension force of the whole bearing is higher than that of a single suspension mode, and the coupling of the extrusion and the synthetic jet is achieved.

2. The gas levitation bearing according to claim 1, characterized in that: The first exciting unit (5) and the second exciting unit (7) are respectively arranged on the modal nodes of the first metal film (2) and the second metal film (4), and the resonance frequency of the first metal film and the second metal film is used as the working frequency, so that the first metal film and the second metal film have the maximum amplitude, the extrusion effect of the first metal film and the second metal film on the gas is stronger, the volume change amount of the cylinder cavity (6) is larger, and finally a greater coupling suspension force can be obtained.

3. The gas levitation bearing according to claim 1 or 2, characterized in that: The first exciting unit (5) and the second exciting unit (7) are ring-shaped or square-shaped, and are used for vibrating to drive the first metal film (2) and the second metal film (4) to vibrate up and down after the exciting electric signals are input.

4. The gas levitation bearing of claim 1, wherein: The first metal film (2) is arranged on the top of the gas suspension bearing and can be controlled to vibrate up and down at a high frequency, so as to generate an extrusion suspension effect.

5. The gas levitation bearing of claim 1, wherein: The second metal film (4) is arranged on the bottom of the bearing and is used for the cylinder cavity (6) and can be controlled to vibrate up and down at a high frequency, so as to change the volume of the cylinder cavity (6) to the maximum extent and enhance the suspension force of the synthetic jet.

6. The gas levitation bearing of claim 1, wherein: The cylinder cavity (6) is in one of cylindrical, circular truncated cone and square shapes and has a gas storage function.

7. The gas levitation bearing of claim 1, wherein: The air flow hole (8) is located on the axis of the cylinder cavity (6), and is a circular or slit hole, which is only used for uniform suction and emission of gas in the cylinder cavity (6) when the synthetic jet suspension effect is generated.

8. The gas levitation bearing of claim 1, wherein: The air flow hole (8) is multiple and arrayed on the first metal film (2), and the center after the array still needs to be located on the axis of the cylinder cavity (6), so as to generate a synthetic jet suspension effect with a larger range.

Images