A piezoelectric-magnetic force coupled air gap height and vibration monitoring device for an air floating bearing

Abstract

This invention relates to a piezoelectric-magnetic coupling air gap height and vibration monitoring device for air bearings, belonging to the fields of gas hydrostatic lubrication and precision motion technology. It includes: a frame with a through-hole structure in the middle, air vents in the frame, and a connection between the frame and an elastic beam; a permanent magnet mounted on the lower side of the middle of the elastic beam; the permanent magnet being located within the through-hole structure in the middle of the frame; and a piezoelectric layer mounted on the upper side of the elastic beam. This invention opens up a new approach for monitoring micro-gap dynamic changes, such as air gap detection, in air bearings, solving the difficulty of dynamically monitoring the air gap height and micro-vibration amplitude during air bearing operation.

Description

Technical Field

[0001] This invention relates to a piezoelectric-magnetic coupling air gap height and vibration monitoring device, belonging to the fields of gas static pressure lubrication and precision motion technology. Background Technology

[0002] Air static pressure bearings rely on an externally supplied compressed air film as a lubricating medium, offering higher load-bearing capacity and stiffness compared to hydrostatic bearings, enabling operation in low-speed environments. Due to their high load-bearing capacity, high stiffness, low friction loss, excellent thermal stability, and long lifespan, air static pressure bearings are widely used in the support and feed systems of ultra-precision machining and measuring equipment. However, due to inherent airflow instability within the load-bearing air film, bearings experience micro-vibrations that are difficult to completely suppress during operation. In applications such as ultra-precision motion stages, which are highly sensitive to micro-displacement and micro-vibration, such vibrations directly limit further improvements in positioning accuracy, measurement stability, and machined surface quality. Existing research largely focuses on measuring the air gap length or bearing mover vibration using external sensors, while research on integrated sensing solutions for air gap conditions, particularly integrated real-time monitoring systems capable of simultaneously measuring air gap height and analyzing vibrations, remains insufficient.

[0003] Therefore, there is an urgent need to propose a piezoelectric-magnetic coupling air gap height and vibration monitoring device for air bearings to solve the above-mentioned technical problems. Summary of the Invention

[0004] To address the problem of real-time monitoring of the air gap height in existing air hydrostatic bearings, a piezoelectric-magnetic coupled air gap height and vibration monitoring device for air bearings is provided. A brief overview of the invention is given below to provide a basic understanding of certain aspects of the invention. It should be understood that this overview is not an exhaustive summary of the invention. It is not intended to identify key or essential parts of the invention, nor is it intended to limit the scope of the invention.

[0005] The technical solution of the present invention: A piezoelectric-magnetic coupling air gap height and vibration monitoring device for air bearings includes: a frame, an elastic beam, a permanent magnet, and a piezoelectric layer; The frame has a through-hole structure in the middle, air holes in the frame, and is connected to the elastic beam; A permanent magnet is installed on the lower middle part of the elastic beam; The permanent magnet is located within the through-hole structure in the middle of the frame; The piezoelectric layer is installed on the upper side of the elastic beam.

[0006] Preferably, a frame is disposed above the ferromagnetic reference surface, and an air gap is formed between the ferromagnetic reference surface and the frame.

[0007] Preferably, the side of the frame is provided with an air supply hole, and the lower side of the frame is provided with a throttling hole. The air supply hole and the throttling hole are connected by a flow channel. Compressed gas enters through the air supply hole and is discharged from the throttling hole to the space between the frame and the ferromagnetic reference surface, thereby generating the air film gap to be measured.

[0008] Preferably, the frame has a hollow groove in the middle, and the permanent magnet is rectangular.

[0009] Preferably, the elastic beam is a rectangular beam with both ends connected to the frame.

[0010] Preferably, the piezoelectric layer is disposed between the connection between the frame and the elastic beam, and between the elastic beam and the permanent magnet. When the elastic beam bends due to magnetic force, the piezoelectric layer is only subjected to bending moment in one direction.

[0011] Preferably, when the frame experiences micro-vibration, the gap between the ferromagnetic reference surface and the permanent magnet changes, and the magnetic attraction between them changes accordingly. The elastic beam will produce corresponding bending strain; Based on the positive piezoelectric effect of the piezoelectric layer, mechanical strain is converted into polarization inside the piezoelectric layer, thereby inducing bound charges proportional to the strain on the electrodes on the surface of the piezoelectric layer film. When the strain of the elastic beam decreases due to the reduction of magnetic force, the charge generated by the piezoelectric layer also decreases accordingly. Subsequently, the high-impedance charge signal output by the piezoelectric layer is converted into a low-impedance voltage signal by the integrated preamplifier circuit, and after processing such as filtering, amplification and analog-to-digital conversion, the digital signal containing static air gap offset and dynamic vibration spectrum information is finally transmitted to the host computer by the wireless transmission module, realizing non-contact gap measurement and status monitoring.

[0012] The present invention has the following beneficial effects: When the frame experiences micro-vibration, the gap between the ferromagnetic reference surface and the permanent magnet changes, and the magnetic attraction between them changes accordingly. This changing attraction acts on the elastic beam, causing it to produce corresponding bending strain. Based on the positive piezoelectric effect of the piezoelectric layer, the mechanical strain is converted into polarization inside the piezoelectric layer, thereby inducing a bound charge proportional to the strain on the electrode on the thin film surface.

[0013] This invention can dynamically adjust the charge output to the data processing and communication circuit according to the distance change between the permanent magnet and the reference surface. After being collected by the data processing and communication circuit, the signal containing static air gap offset and dynamic vibration spectrum information is sent to the host computer. The distance change between the frame and the reference surface can be obtained in real time based on the signal.

[0014] This invention opens up a new approach to monitoring the dynamic changes in micro-gap, such as the air gap detection, of air bearings, which helps to solve the difficulties in dynamically monitoring the air gap height and micro-vibration amplitude during the operation of air bearings. Attached Figure Description

[0015] Figure 1 A schematic diagram of the magnetic-piezoelectric coupling air gap height and vibration monitoring device provided in the embodiments of this application; Figure 2 This is a side cross-sectional view of the magnetic-piezoelectric coupling air gap height and vibration monitoring device provided in an embodiment of this application.

[0016] In the diagram: 1-frame, 2-ferromagnetic reference surface, 3-elastic beam, 4-permanent magnet, 5-piezoelectric layer, 6-air supply port, 7-throttling port. Detailed Implementation

[0017] To make the objectives, technical solutions, and advantages of this invention clearer, the invention is described below with reference to specific embodiments shown in the accompanying drawings. However, it should be understood that these descriptions are merely exemplary and not intended to limit the scope of the invention. Furthermore, descriptions of well-known structures and technologies are omitted in the following description to avoid unnecessarily obscuring the concept of the invention.

[0018] Specific implementation method one: Combining Figure 1-2 This embodiment describes a piezoelectric-magnetic coupling air gap height and vibration monitoring device for air bearings, comprising: a frame 1, an elastic beam 3, a permanent magnet 4, and a piezoelectric layer 5. The middle part of frame 1 has a through-hole structure, and the frame 1 is as follows: Figure 2 Air holes are provided on the front and rear sides, and the frame 1 is connected to the elastic beam 3; A permanent magnet 4 is fixedly installed on the lower middle part of the elastic beam 3; The permanent magnet 4 is located in the through-hole structure in the middle of the frame 1; The piezoelectric layer 5 is fixedly installed on the upper side of the elastic beam 3.

[0019] Specific Implementation Method Two: Combining Figure 1-2 This embodiment describes a piezoelectric-magnetic coupling air gap height and vibration monitoring device for air bearings, such as... Figure 2 A frame 1 is set above the ferromagnetic reference surface 2. An air gap is formed between the ferromagnetic reference surface 2 and the frame 1, that is, the ferromagnetic reference surface 2 does not contact the frame 1 or the permanent magnet 4, and there is a gas film gap to be measured between the frame and the reference surface.

[0020] Specific implementation method three: Combining Figure 1-2This embodiment describes a piezoelectric-magnetic coupling air gap height and vibration monitoring device for air bearings. The right side of the frame 1 has an air supply port 6, and the lower side of the frame 1 has a throttling orifice 7. One air supply port 6 and a row of corresponding throttling orifices 7 evenly arranged in the left-right direction are connected by an air passage. Several air ports are evenly arranged in the front-back direction. Compressed gas enters through the air supply port 6 and exits through the throttling orifice 7 between the frame 1 and the ferromagnetic reference surface 2, generating the air film gap to be measured. Contact between the reference surface and the permanent magnet should be avoided.

[0021] Specific implementation method four: Combination Figure 1-2 This embodiment describes a piezoelectric-magnetic coupling air gap height and vibration monitoring device for air bearings. The through hole in the middle of the frame 1 is rectangular, the permanent magnet 4 is cuboid, and the permanent magnet 4 may not contact the inner wall of the through hole.

[0022] Specific Implementation Method Five: Combining Figure 1-2 This embodiment describes a piezoelectric-magnetic coupling air gap height and vibration monitoring device for air bearings. The longitudinal section of the elastic beam 3 is rectangular. The elastic beam 3 is as follows... Figure 2 The left and right ends of the middle section are fixedly connected to the left and right sides of the frame 1, respectively.

[0023] Specific Implementation Method Six: Combination Figure 1-2 This embodiment describes a piezoelectric-magnetic coupling air gap height and vibration monitoring device for air bearings. The piezoelectric layer 5 is disposed between the connection between the frame 1 and the elastic beam 3, and between the elastic beam 3 and the permanent magnet 4. When the elastic beam 3 bends due to magnetic force, the piezoelectric layer 4 is only subjected to bending moment in one direction, avoiding the mutual cancellation of charges generated by bending moments in different directions. This converts the deformation of the structure into strain with the maximum amplitude to improve energy conversion efficiency. Moreover, the stress field is uniform, ensuring reliable performance and high cost-effectiveness.

[0024] Specific implementation method seven: Combination Figure 1-2 This embodiment describes a piezoelectric-magnetic coupling air gap height and vibration monitoring device for air bearings. When the frame 1 experiences micro-vibration, the gap between the ferromagnetic reference surface 2 and the permanent magnet changes, and the magnetic attraction between them changes accordingly. The reduction in air gap height will lead to an increase in attractive force. This change in attractive force acts on the elastic beam 3, causing the elastic beam 3 to produce corresponding bending strain. The piezoelectric layer, analog signal conditioning module, analog-to-digital conversion module, digital processing and communication module, and host computer are sequentially connected. Based on the positive piezoelectric effect of the piezoelectric layer 5, mechanical strain is converted into polarization inside the piezoelectric layer 5, thereby inducing bound charges proportional to the strain on the electrodes on the surface of the piezoelectric layer film. When the strain of the elastic beam 3 decreases due to the reduction of magnetic force, the charge generated by the piezoelectric layer 5 also decreases accordingly. Subsequently, the high-impedance charge signal output by the piezoelectric layer 5 is converted into a low-impedance voltage signal by the integrated preamplifier circuit, and after processing such as filtering, amplification and analog-to-digital conversion, the digital signal containing static air gap offset and dynamic vibration spectrum information is finally transmitted to the host computer by the wireless transmission module, realizing non-contact gap measurement and status monitoring.

[0025] Example 1: Combination Figure 1-2 The device shown is a piezoelectric-magnetic coupling air gap height and vibration monitoring device for air bearings, which monitors the dynamic changes of micro gaps. It includes: a frame 1, a ferromagnetic reference surface 2, an elastic beam 3, a permanent magnet 4, and a piezoelectric layer 5. The elastic beam is connected to the frame with fixed supports at both ends, and the permanent magnet is fixed to the center of the elastic beam by screws or adhesive bonding. The frame has an air supply port 6 and a throttling port 7. Compressed gas enters through the air supply port and exits through the throttling port to the space between the frame and the ferromagnetic reference surface, forming a high-pressure gas film. This creates a gas film gap to be measured between the ferromagnetic reference surface and the permanent magnet. Contact between the reference surface and the permanent magnet should be avoided. The piezoelectric layer is adhered to the space between the fixed end of the elastic beam and the outside of the permanent magnet installation position, ensuring that when the elastic beam bends due to magnetic force, the piezoelectric layer is only subjected to bending moment in one direction. The piezoelectric layer is connected to the data processing and communication circuit. The data processing and communication circuit collects the charge generated by the piezoelectric layer and converts it into voltage. After processing such as filtering, amplification and analog-to-digital conversion, the signal containing static air gap offset and dynamic vibration spectrum information is finally transmitted to the host computer by the wireless transmission module. When the frame experiences micro-vibration, the gap between the ferromagnetic reference surface and the permanent magnet changes, and the magnetic attraction between them changes accordingly. The decrease in air gap height leads to an increase in the attraction force, which acts on the elastic beam, causing it to produce corresponding bending strain. Based on the positive piezoelectric effect of the piezoelectric layer, the mechanical strain is converted into polarization within the piezoelectric layer, thereby inducing bound charges proportional to the strain on the electrodes on the thin film surface. When the strain of the elastic beam decreases due to the decrease in magnetic force, the charge generated by the piezoelectric layer also decreases accordingly. Subsequently, the high-impedance charge signal output by the piezoelectric layer is converted into a low-impedance voltage signal by the integrated preamplifier circuit, and after processing such as filtering, amplification, and analog-to-digital conversion, the digital signal containing static air gap offset and dynamic vibration spectrum information is finally transmitted to the host computer by the wireless transmission module, realizing non-contact gap measurement and status monitoring.

[0026] It should be noted that in the above embodiments, as long as the technical solutions are not contradictory, they can be permuted and combined. Those skilled in the art can exhaust all possibilities based on the mathematical knowledge of permutation and combination. Therefore, the present invention will not describe the technical solutions after permutation and combination one by one, but it should be understood that the technical solutions after permutation and combination have been disclosed by the present invention.

[0027] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A piezo-magnetic force coupled air gap height and vibration monitoring device for an air bearing, characterized by: include: The frame (1) has a through hole structure in the middle, the frame (1) is provided with air holes, and the frame (1) is connected to the elastic beam (3); A permanent magnet (4) is installed on the lower side of the middle part of the elastic beam (3); The permanent magnet (4) is located in the middle through-hole structure of the frame (1); The piezoelectric layer (5) is installed on the upper side of the elastic beam (3).

2. The piezoelectric-magnetic coupling air gap height and vibration monitoring device for air bearings according to claim 1, characterized in that: A frame (1) is provided above the ferromagnetic reference surface (2), and an air gap is formed between the ferromagnetic reference surface (2) and the frame (1).

3. The piezoelectric-magnetic coupling air gap height and vibration monitoring device for air bearings according to claim 2, characterized in that: The side of the frame (1) is provided with an air supply hole (6) and the lower side of the frame (1) is provided with a throttling hole (7). The air supply hole (6) and the throttling hole (7) are connected through a flow channel. Compressed gas enters through the air supply hole (6) and is discharged from the throttling hole (7) to generate the gas film gap to be measured between the frame (1) and the ferromagnetic reference surface (2).

4. The piezoelectric-magnetic coupling air gap height and vibration monitoring device for air bearings according to claim 3, characterized in that: The frame (1) has a hollow groove in the middle, and the permanent magnet (4) is rectangular.

5. The piezoelectric-magnetic coupling air gap height and vibration monitoring device for air bearings according to claim 4, characterized in that: The elastic beam (3) is a rectangular beam, and both ends of the elastic beam (3) are connected to the frame (1).

6. The piezoelectric-magnetic coupling air gap height and vibration monitoring device for air bearings according to claim 5, characterized in that: The piezoelectric layer (5) is disposed between the connection between the frame (1) and the elastic beam (3) and the connection between the elastic beam (3) and the permanent magnet (4). When the elastic beam (3) bends due to magnetic force, the piezoelectric layer (4) is only subjected to bending moment in one direction.

7. A piezoelectric-magnetic coupling air gap height and vibration monitoring device for air bearings according to claim 2 or 6, characterized in that: When the frame (1) vibrates slightly, the gap between the ferromagnetic reference surface (2) and the permanent magnet changes, and the magnetic attraction between them changes accordingly. The elastic beam (3) generates corresponding bending strain; Based on the positive piezoelectric effect of the piezoelectric layer (5), mechanical strain is converted into polarization inside the piezoelectric layer (5), thereby inducing bound charges proportional to the strain on the surface electrodes of the thin film. When the strain of the elastic beam (3) decreases due to the decrease of magnetic force, the charge generated by the piezoelectric layer (5) also decreases accordingly. The high impedance charge signal output by the piezoelectric layer (5) is converted into a low impedance voltage signal by the integrated preamplifier circuit, and after filtering, amplification and analog-to-digital conversion, the digital signal containing static air gap offset and dynamic vibration spectrum information is transmitted to the host computer by the wireless transmission module, realizing non-contact gap measurement and status monitoring.

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