Method for testing bump foil creep of foil dynamic pressure radial gas bearing

Abstract

The invention belongs to the technical field of bearings, and discloses a foil dynamic pressure radial gas bearing bump foil creep test method, which is characterized in that a miniature rubber block is inserted between a top foil and a rigid substrate, and the miniature rubber block is used as a flexible element, is in direct contact with the top foil, and deforms under the action of a compression load transmitted by the top foil; a monocrystalline silicon semiconductor strain gauge is pasted on the side face of the miniature rubber block, and the direction is perpendicular to the direction of the compression load; in the running process of the bearing, the output strain value of the strain gauge is monitored in real time through a data acquisition system; the semiconductor strain gauge is a sensitive element manufactured based on the piezoresistive effect of semiconductor monocrystalline silicon, the resistivity of a semiconductor crystal material is changed when the semiconductor crystal material is stressed in a certain direction and deforms, and strain, stress and the like are indirectly measured. The device has the beneficial effect that the problem that the creep strain is difficult to test in real time due to the tiny structure of the bump foil is solved.

Description

Technical Field

[0001] This invention relates to the field of bearing technology, and in particular to a testing device and method for the creep of foil dynamic pressure radial bearings. Background Technology

[0002] Foil dynamic radial bearings are air bearings with a flexible surface composed of one or more layers of corrugated foil and top foil. They have advantages such as small weight, high reliability, great design freedom, good high temperature characteristics, and low or no maintenance. They are widely used in aircraft air circulation systems, small aero engines, micro gas turbines, oil-free air compressors for fuel cells, and vehicle turbochargers.

[0003] The corrugated foil and top foil are the most important components of foil-type hydrodynamic radial bearings, serving to support the rotor and provide stiffness and frictional damping for the bearing. Currently, Inconel X-750 nickel-based superalloy is widely used as the foil material both domestically and internationally. This material possesses certain high-temperature resistance and high elasticity, exhibiting high strength below 800℃ and good relaxation resistance below 540℃. However, when the temperature rises further or the bearing is exposed to high-temperature environments for extended periods, creep inevitably occurs in the foil structure. Creep leads to deformation, damage, buckling, and cracking of the foil structure, resulting in failure at high temperatures. Monitoring the creep behavior of the foil structure is crucial for ensuring the reliability of foil-type hydrodynamic radial bearings at high temperatures.

[0004] Therefore, it is necessary to provide a testing device and method for the creep of a foil-coated radial bearing to solve the problem of difficulty in real-time testing of creep strain due to the small size of the foil structure. Summary of the Invention

[0005] This invention discloses a testing device and method for the creep of foil dynamic pressure radial bearing wave foil, which can effectively solve the technical problems involved in the background art.

[0006] To achieve the above objectives, the technical solution of the present invention is as follows: A testing device and method for the creep of a foil dynamic pressure radial bearing is disclosed. The foil dynamic pressure radial bearing includes a top foil and a corrugated foil. The testing device includes an integrated sensor and a data acquisition system. The integrated sensor includes rubber and a strain gauge. The rubber is connected to the corrugated foil and positioned relative to the top foil. The strain gauge is mounted on the rubber and connected to the data acquisition system. When the foil dynamic pressure radial bearing is in operation, the top foil compresses the rubber, and the strain gauge outputs corresponding information to the data acquisition system based on the deformation of the rubber.

[0007] The application provides a foil dynamic pressure radial gas bearing wave foil creep testing device based on embedded micro strain gauge sensing technology, a sensor is integrated between a wave foil and a top foil of a gas foil bearing, and a core component is a micro rubber block, the rubber block directly contacts the top foil and can effectively transmit compression load received by the top foil. A single crystal silicon semiconductor strain gauge is attached to a side surface of the rubber block and is perpendicular to the compression load direction, so that deformation of the rubber block can be accurately captured. During operation of the gas foil bearing, the top foil applies compression force to the rubber block, the rubber block is deformed, and then the strain gauge attached to the rubber block is strained. Corresponding strain data are analyzed, the deformation amount of the rubber block can be quantified, the deformation amount is directly related to a creep amount of the wave foil structure under load, and the problem that real-time creep strain testing is difficult due to small wave foil structure can be solved.

[0008] As a preferred improvement of the application, the rubber is located between wave crests of the wave foil, one side of the rubber is mounted on the wave foil, and the other side is in abutment with the top foil.

[0009] As a preferred improvement of the application, the strain gauge is attached to a side surface of the rubber and is perpendicular to the compression load direction.

[0010] As a preferred improvement of the application, the testing device further comprises a base, the base is mounted on the wave foil, and the rubber is mounted on the base. The base is used for placing the rubber block and the strain gauge, and provides a fixed mounting carrier for the sensing unit composed of the micro rubber block and the strain gauge; a plurality of micro rubber blocks and strain gauges can be uniformly fixed on a rigid base with the same axial length as the bearing, to form an integrated micro embedded strain displacement sensor, and the sensing unit does not need to be installed individually.

[0011] As a preferred improvement of the application, the base is in a plurality, is mounted between different wave crests of the top foil, and a plurality of integrated sensors are mounted on each base.

[0012] As a preferred improvement of the application, the data acquisition system comprises a NICDAQ-9178 and a NI9235, and the strain gauge is a TP series semiconductor strain gauge.

[0013] A foil dynamic pressure radial bearing wave foil creep testing method, which adopts the testing device and comprises the following steps. S1, the rubber and the strain gauge are mounted between the top foil and the wave foil, and the data acquisition system is connected; S2, the foil dynamic pressure radial bearing is operated, and the strain gauge outputs data; S3, a relationship between output voltage Uo of the strain gauge and strain ε of the strain gauge is: ; wherein U in is the bridge excitation voltage, G F is the gauge factor (sensitivity coefficient) of the strain gauge, indicating that the output voltage Uo is linearly related to the strain ε; S4, the relationship between the strain ε of the strain gauge and the deformation amount ΔL of the rubber is: ; wherein μ is the Poisson's ratio of the rubber, L is the initial height of the rubber, and the deformation amount ΔL of the rubber, i.e., the creep deformation amount of the wave foil, is deduced from the strain ε of the strain gauge.

[0014] A micro rubber block is inserted between the top foil and the rigid base, which serves as a compliant element and is in direct contact with the top foil and deforms under the compression load transmitted by the top foil; a single-crystal silicon semiconductor strain gauge is attached to the side of the micro rubber block, in a direction perpendicular to the direction of the compression load; during the operation of the bearing, the output strain value of the strain gauge is monitored in real time by a data acquisition system; the semiconductor strain gauge is a sensitive element made based on the piezoresistive effect of semiconductor single-crystal silicon, and the resistivity of the semiconductor crystal material changes when the material deforms under stress in a certain direction, indirectly measuring the strain, stress, etc. By analyzing the strain data, the deformation amount of the micro rubber block is quantified, and the creep deformation amount of the wave foil structure is obtained. NICDAQ-9178+NI9235 is purchased to provide bridge pressure, signal amplification, wave, and analog-to-digital conversion, and software Labview is used for data display and storage to form a data acquisition system, which can record and analyze the strain value in real time.

[0015] As a preferred improvement of the present application: in step S4, the relationship between the deformation amount ΔL of the rubber and the compression load F applied by the top foil is: ; wherein F is the compression load applied by the top foil, A is the cross-sectional area of the rubber, and E is the elastic modulus of the rubber.

[0016] As a preferred improvement of the present application: the number of integrated sensors is multiple, and they are installed at different positions of the wave foil. Multiple micro rubber blocks and micro strain gauges are integrated on a rigid base with the same axial length as the bearing, forming an integrated micro embedded strain displacement sensor, which is convenient for embedding and disassembling. Multiple integrated micro embedded strain displacement sensors are arranged circumferentially along the wave foil span, with an average of 6 in the axial direction, forming a sensor matrix, which can realize comprehensive measurement of the entire wave foil creep surface.

[0017] As a preferred improvement of the present application: the rubber is cuboid. It ensures that the rubber block can correctly transmit the deformation of the top foil, and the strain gauge is in contact with the rubber block plane, so that the strain gauge can transmit the strain. Structures that meet the above requirements can be used, including prisms such as cuboids and cubes.

[0018] The beneficial effects of the present application are as follows: During the operation of the gas foil bearing, the top foil exerts a compression force on the rubber, causing the rubber to deform, which in turn causes the strain gauge attached to the rubber to produce strain. By analyzing the strain data, the deformation of the rubber block can be quantified, and this deformation is directly related to the creep of the wave foil structure under load, which can be used to solve the problem of real-time testing of creep strain caused by the small size of the wave foil structure. BRIEF DESCRIPTION OF DRAWINGS

[0019] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiment description. Obviously, the drawings in the following description are only some embodiments of the present application, and for those skilled in the art, other drawings can be obtained without creative labor based on these drawings, wherein: Figure 1 Figure is a schematic diagram of a foil dynamic pressure radial bearing wave foil creep testing device of the present application; Figure 2 Figure is a schematic diagram of the installation of the testing device of the present application.

[0020] In the figure: 100-integrated sensor, 110-rubber, 120-strain gauge, 200-substrate, 300-top foil, 400-wave foil, 500-bearing shell. DETAILED DESCRIPTION

[0021] The technical solutions in the embodiments of the present application will be described clearly and completely in the following with reference to the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, not all. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0022] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present application are only used to explain the relative positional relationship, movement condition, etc. between the components in a certain posture (as shown in the drawings), if the certain posture changes, the directional indications also change accordingly.

[0023] In addition, the descriptions such as "first", "second" and the like in the present application are only for the purpose of description, and cannot be understood as indicating or implying the relative importance of the technical features indicated, or implicitly indicating the number of the technical features indicated. Therefore, the features defined as "first", "second" can be explicitly or implicitly included at least one of the features. In the description of the present application, the meaning of "a plurality of" is at least two, for example, two, three, etc., unless otherwise explicitly specified and limited.

[0024] In the present application, unless otherwise explicitly specified and limited, the terms "connection", "fixation" and the like should be understood broadly, for example, "fixation" can be fixed connection, or detachable connection, or integral; can be mechanical connection, or electrical connection; can be direct connection, or indirect connection through intermediate medium; can be internal communication of two elements or interaction relationship between two elements, unless otherwise explicitly limited. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0025] In addition, the technical solutions of various embodiments of the present application can be combined with each other, but it must be based on the fact that a person skilled in the art can realize it, when the combination of technical solutions appears contradictory or unachievable, it should be considered that the combination of technical solutions does not exist, nor within the protection scope required by the present application.

[0026] Please refer to Figure 1 As shown in the drawings, the present application provides a kind of foil dynamic pressure radial bearing wave foil creep test device, and foil dynamic pressure radial bearing includes top foil 300 and wave foil 400, test device includes integrated sensor 100 and data acquisition system, the integrated sensor 100 includes rubber 110 and strain gauge 120, the rubber 110 is connected with the wave foil 400 and is arranged relative to the top foil 300, the strain gauge 120 is installed on the rubber 110 and is connected with the data acquisition system;When foil dynamic pressure radial bearing works, the top foil 300 extrudes the rubber 110, and the strain gauge 120 exports corresponding information to the data acquisition system according to the deformation of the rubber 110.The present application proposes a kind of foil dynamic pressure radial gas bearing wave foil creep test device based on embedded micro strain gauge sensing technology, testing is carried out by integrated sensor between foil dynamic pressure radial gas bearing wave foil and top foil.

[0027] As an embodiment, the rubber 110 is located between the wave crests of the wave foil 400, one side of the rubber 110 is mounted on the wave foil 400, and the opposite side is in contact with the top foil 300. The strain gauge 120 is attached to the side of the rubber 110, and the direction is perpendicular to the direction of the compression load. The test device further comprises a substrate 200, which is mounted on the wave foil 400, and the rubber 110 is mounted on the substrate 200. The substrate 200 is in a plurality, and is respectively mounted between different wave crests of the top foil 300, and a plurality of integrated sensors 100 are mounted on each substrate 200. The data acquisition system comprises NICDAQ-9178 and NI9235, and the strain gauge 120 is a TP series semiconductor strain gauge.

[0028] A test method for the creep of a foil dynamic pressure radial bearing wave foil, comprising the following steps: S1, mounting the rubber 110 and the strain gauge 120 between the top foil 300 and the wave foil 400, and connecting the data acquisition system; S2, operating the foil dynamic pressure radial bearing, and the strain gauge 120 outputs data; S3, the relationship between the output voltage Uo of the strain gauge 120 and the strain ε of the strain gauge is: ; Where U in is the bridge excitation voltage (data of NI9235), G F is the strain gauge factor of the strain gauge 120; S4, the relationship between the strain ε of the strain gauge 120 and the deformation amount ΔL of the rubber 110 is: ; Where μ is the Poisson's ratio of the rubber 110, L is the initial height of the rubber 110, and the deformation amount ΔL of the rubber 110 is deduced from the strain ε of the strain gauge 120, that is, the creep deformation amount of the wave foil 400.

[0029] In the step S4, the relationship between the deformation amount ΔL of the rubber 110 and the compression load F applied by the top foil 300 is: ; Where F is the compression load applied by the top foil 300, A is the cross-sectional area of the rubber 110, and E is the elastic modulus of the rubber 110.

[0030] As an embodiment, the number of integrated sensors 100 is a plurality, which are mounted at different positions of the wave foil 400, and the rubber 110 is in the shape of a cuboid. Embodiment

[0031] Micro rubber blocks are inserted between the wave foil and the rigid substrate, which serve as compliant elements and deform when the top foil receives a compressive load. Strain gauges (Nanjing Tian Guang Electrical Technology Co., Ltd. TP-5-30) are attached to each micro rubber block on the side of the rubber block, perpendicular to the direction of the compressive load. The strain gauges are connected to a data acquisition system, and the output strain values of the strain gauges are monitored during the operation of the bearing. By analyzing the strain data, the deformation of the micro rubber block is quantified, and the creep deformation of the wave foil structure is obtained. Multiple micro rubber blocks and micro strain gauges are integrated into a rigid substrate that is the same length as the axial length of the bearing, forming an integrated micro embedded strain displacement sensor that is easy to embed and disassemble. Multiple micro embedded strain displacement sensors are arranged axially along the wave foil span, forming a sensor matrix that comprehensively measures the entire wave foil creep surface. As shown in Figure 2

[0032] The relationship between the output strain ε of the strain gauge and the deformation ΔL of the micro rubber block is:

[0033] By measuring the output strain ε of the strain gauge, the deformation ΔL of the micro rubber block is deduced, and the creep deformation of the wave foil structure is obtained.

[0034] The compressive load applied by the top foil is calculated by the following formula:

[0035] Where F is the compressive load applied by the top foil, L is the initial height of the micro rubber block, A is the cross-sectional area of the micro rubber block, and E is the elastic modulus of the rubber.

[0036] Working principle: The top foil applies a compressive force to the rubber, causing the rubber to deform, which in turn causes the strain gauge attached to the rubber to produce strain. By analyzing the strain data, the deformation of the rubber block can be quantified, and this deformation is directly related to the creep of the wave foil structure under load.

[0037] Although the embodiments of the present application have been disclosed as above, they are not limited to the application listed in the specification and the embodiments, and can be fully applied to various fields suitable for the present application. For those skilled in the art, additional modifications can be easily realized, and therefore the present application is not limited to specific details and the figures shown and described herein, without departing from the general concept defined by the claims and the equivalent scope.​

Claims

1. A testing device for the creep of a foil dynamic pressure radial bearing, the foil dynamic pressure radial bearing comprising a top foil (300) and a corrugated foil (400), characterized in that: The testing device includes an integrated sensor (100) and a data acquisition system. The integrated sensor (100) includes a rubber (110) and a strain gauge (120). The rubber (110) is connected to the corrugated foil (400) and disposed relative to the top foil (300). The strain gauge (120) is mounted on the rubber (110) and connected to the data acquisition system. When the foil dynamic pressure radial bearing is working, the top foil (300) squeezes the rubber (110), and the strain gauge (120) outputs corresponding information to the data acquisition system according to the deformation of the rubber (110).

2. The testing device for the creep of a foil dynamic pressure radial bearing according to claim 1, characterized in that: The rubber (110) is located between the crests of the corrugated foil (400), with one side of the rubber (110) mounted on the corrugated foil (400) and the other side abutting against the top foil (300).

3. The testing device for the creep of a foil dynamic pressure radial bearing according to claim 1, characterized in that: The strain gauge (120) is attached to the side of the rubber (110) in a direction perpendicular to the direction of the compressive load.

4. The testing device for the creep of a foil dynamic pressure radial bearing according to claim 1, characterized in that: The testing device also includes a substrate (200) mounted on the corrugated foil (400) and a rubber (110) mounted on the substrate (200).

5. The testing device for the creep of a foil dynamic pressure radial bearing according to claim 4, characterized in that: There are multiple substrates (200), which are respectively installed between different peaks of the top foil (300), and multiple integrated sensors (100) are installed on each substrate (200).

6. The testing device for the creep of a foil dynamic pressure radial bearing according to claim 1, characterized in that: The data acquisition system includes NICDAQ-9178 and NI9235, and the strain gauge (120) is a TP series semiconductor strain gauge.

7. A method for testing the creep of a foil-based radial bearing with dynamic pressure, characterized in that: Using the testing apparatus according to any one of claims 1-6, the testing method includes the following steps: S1. Install the rubber (110) and the strain gauge (120) between the top foil (300) and the corrugated foil (400), and connect the data acquisition system; S2, the foil dynamic pressure radial bearing is operated, and the strain gauge (120) outputs data; S3. The relationship between the output voltage Uo of the strain gauge (120) and the strain ε of the strain gauge is as follows: ; U in It is the bridge excitation voltage, G F It is the strain gauge factor of the strain gauge (120); S4. The relationship between the strain ε of the strain gauge (120) and the deformation ΔL of the rubber (110) is as follows: ; Where μ is the Poisson's ratio of the rubber (110) and L is the initial height of the rubber (110). The deformation amount ΔL of the rubber (110) is derived from the strain ε of the strain gauge (120), which is the creep deformation amount of the corrugated foil (400).

8. The method for testing the creep of a foil-based radial bearing with dynamic pressure according to claim 7, characterized in that: In step S4, the relationship between the deformation amount ΔL of the rubber (110) and the compressive load F applied by the top foil (300) is as follows: ; Wherein, F is the compressive load applied by the top foil (300), A is the cross-sectional area of ​​the rubber (110), and E is the elastic modulus of the rubber (110).

9. The method for testing the creep of a foil-based radial bearing with dynamic pressure according to claim 7, characterized in that: The number of integrated sensors (100) is multiple, and they are installed at different positions on the corrugated foil (400).

10. A method for testing the creep of a foil-based radial bearing with dynamic pressure according to claim 7, characterized in that: The rubber (110) is rectangular.

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