Air bearing device and bearing clearance adjusting method

Abstract

The invention relates to the technical field of air bearings, and discloses an air bearing device and a bearing clearance adjusting method.The air bearing device comprises a rotating shaft, a bearing base body and a mounting shell, the bearing base body comprises an inner base body, a heat insulation layer and an outer base body, the outer base body is made of a low-thermal-expansion-coefficient material, and the inner base body is made of a high-thermal-expansion-coefficient material; when the bearing base body is heated, the inner base body is slightly heated to expand, outward expansion of the inner base body is restrained by the outer base body of the low-expansion base body, and only uniform inward radial deformation is generated, so that the inner diameter of the inner base body is slightly reduced; the bearing base body is designed to be of a layered structure of the inner base body, the heat insulation layer and the outer base body, materials with the high thermal expansion coefficient and materials with the low thermal expansion coefficient are selected, temperature control of the temperature control pipeline is matched, fine adjustment of a bearing gap is achieved, and the problems that a traditional air bearing gap is fixed and cannot be flexibly adjusted according to working requirements are solved; and the adaptability and the working stability of the air bearing are greatly improved.

Description

Technical Field

[0001] This invention relates to the field of air bearing technology, specifically to an air bearing device and a bearing clearance adjustment method. Background Technology

[0002] Air bearings are precision support components that utilize a gas film to bear loads and achieve non-contact rotation of rotating parts. With their advantages of extremely low friction coefficient, high rotational accuracy, low wear, and long service life, they are widely used in fields with extremely high requirements for rotational accuracy and stability, such as high-speed precision machine tools, aerospace equipment, precision instruments, and semiconductor manufacturing equipment. Their core working principle is to introduce compressed air into the gap between the bearing and the rotating shaft to form a stable air film, which suspends the rotating shaft and enables non-contact relative movement between the rotating shaft and the inner wall of the bearing. This significantly reduces friction during rotation, avoids mechanical wear, and ensures high-speed and precision operation of the equipment. Most existing air bearing devices have a fixed bearing clearance, meaning the inner diameter of the bearing base is fixed. This prevents flexible adjustment of the air flotation film thickness according to changes in the actual working environment, resulting in poor adaptability of the air bearing. In practical applications, when the workload increases, the fixed bearing clearance leads to insufficient load-bearing capacity of the air flotation film, easily causing air flotation film rupture and wear between the rotating shaft and the inner wall of the bearing. This affects the operational stability and service life of the equipment. When the speed is adjusted or the ambient temperature changes, the bearing base and rotating shaft will deform due to thermal expansion and contraction. The fixed bearing clearance may become too large or too small. If it is too large, the air flotation film will lack stability and affect rotational accuracy. If it is too small, the air flotation film may not form, resulting in dry friction. Therefore, there is a need for an air bearing that can adjust the bearing clearance and thus change the thickness of the air flotation film. Summary of the Invention

[0003] The purpose of this invention is to address the shortcomings of existing air bearings, such as fixed bearing clearance and inability to flexibly adjust the thickness of the air flotation film, and to propose an air bearing device and bearing clearance adjustment method.

[0004] To achieve the above objectives, the present invention provides the following technical solution: an air bearing device, comprising: a rotating shaft, a bearing base, and a mounting shell; A heat insulation cylinder is installed on the rotating shaft, and the outer wall of the heat insulation cylinder is on the same plane as the outer wall of the rotating shaft. The bearing base includes an inner base, a heat insulation layer, and an outer base. The inner base, heat insulation layer, and outer base are arranged sequentially outward from the axis. The outer base is made of a material with a low coefficient of thermal expansion, while the inner base is made of a material with a high coefficient of thermal expansion. The inner base is equipped with an air supply pipeline and a temperature control pipeline. When the bearing base is heated, the inner base expands slightly due to heat. Its outward expansion is constrained by the low-expansion outer base, resulting in only uniform inward radial deformation, which causes a slight reduction in the inner diameter of the inner base. The mounting housing is equipped with a gas supply structure and a temperature control structure, which are used to supply gas to the gas supply pipeline and control the temperature of the temperature control pipeline, respectively.

[0005] As a further embodiment of the present invention, the rotating shaft, the bearing base and the mounting shell are coaxial and arranged radially outward along the axis. The inner wall of the mounting shell is in close contact with the outer wall of the bearing base, and a gap is provided between the bearing base and the outer wall of the rotating shaft. This gap is an air flotation film.

[0006] As a further embodiment of the present invention, the length of the heat insulation cylinder is greater than the length of the bearing base, and its two ends extend beyond the two ends of the bearing base.

[0007] As a further embodiment of the present invention, the air supply pipeline includes an air vent groove formed in the inner base, a solid air supply pipe body, and a buffer wrapping layer wrapped around the air supply pipe body. The air supply pipe body is tightly disposed in the air vent groove, conforming to the shape of the inner wall of the air vent groove, but does not extend to the air outlet at the outlet end of the air vent groove.

[0008] As a further embodiment of the present invention, the temperature control pipeline is a micro-tube array coaxial with the bearing substrate, wherein multiple tubes are evenly arranged around the axis.

[0009] As a further aspect of the present invention, the high thermal expansion coefficient material selected for the inner matrix includes at least beryllium copper, titanium copper alloy and austenitic stainless steel.

[0010] As a further aspect of the present invention, the outer substrate material is selected from materials with low thermal expansion coefficients, including at least Invar alloy and pressureless sintered silicon carbide.

[0011] As a further embodiment of the present invention, the heat insulation layer is made of the same material as the outer substrate, and its inner wall is provided with a silver coating.

[0012] As a further aspect of the present invention, a temperature regulating passage is provided on the outer substrate. The air inlet of the temperature regulating passage is connected to the air supply structure, and the mounting shell at the corresponding position of the air outlet is a hollow structure. During operation, the air supply structure provides air that is discharged from the hollow part of the mounting shell through the temperature regulating passage, so as to make the temperature of the outer substrate approach the air temperature.

[0013] A method for adjusting the bearing clearance of an air bearing device includes the following steps: Step 1: Start the air supply structure and introduce compressed air into the air supply pipeline. The compressed air is discharged through the air outlet at the outlet end of the air supply pipe body and the air channel to the gap between the bearing base and the rotating shaft, forming a stable air flotation film, which makes the rotating shaft suspend and achieves a non-contact state with the inner wall of the bearing base. At the same time, the air supply structure introduces air into the temperature regulation channel to remove excess heat from the outer base and make the temperature of the outer base gradually approach the air temperature. Step 2: When it is necessary to adjust the bearing clearance and change the thickness of the air flotation film, taking the reduction of the bearing clearance as an example, first activate the temperature control structure, and use the temperature control pipeline to uniformly control the temperature of the substrate inside the bearing base. In the initial stage, the inner substrate is heated with low heat power. The silver coating on the inner wall of the heat insulation layer reflects the heat, reducing the heat transfer to the heat insulation layer and the outer substrate, and avoiding thermal deformation of the outer substrate. Step 3: Monitor the gap size of the air flotation film in real time, and adjust the temperature control parameters of the temperature control structure in combination with the preset bearing gap standard to change the degree of heating of the inner matrix. With the help of the high thermal expansion coefficient of the inner matrix, it will produce uniform inward radial deformation under the constraint of the low thermal expansion coefficient of the outer matrix, gradually reduce the inner diameter of the inner matrix, and then fine-tune the bearing gap. Step 4: During the gap adjustment process, the air supply pressure of the air supply structure is kept stable to ensure the load-bearing capacity and stability of the air flotation membrane. At the same time, air is continuously introduced through the temperature control channel to ensure that the temperature of the outer substrate is always close to the air temperature, so as to avoid temperature fluctuations affecting the outer substrate and thus affecting the gap adjustment accuracy. Meanwhile, the heat insulation effect of the heat insulation cylinder is monitored to prevent the rotating shaft from being deformed by the heat of the inner substrate. Step 5: When the bearing clearance is detected to reach the preset standard, reduce the power of the temperature control structure to maintain the same heating and cooling efficiency of the inner substrate, while maintaining the air supply to the air supply structure and temperature regulation path to keep the adjusted bearing clearance stable.

[0014] Compared with the prior art, the beneficial effects of the present invention are: This invention achieves fine-tuning of the bearing clearance by designing the bearing substrate as a layered structure consisting of an inner substrate, a heat insulation layer, and an outer substrate, using materials with high and low coefficients of thermal expansion respectively. Combined with temperature control via a temperature control pipeline, this solves the problem of fixed clearance in traditional air bearings, which cannot be flexibly adjusted according to operational requirements. This significantly improves the adaptability and operational stability of air bearings. Simultaneously, the heat insulation cylinder on the rotating shaft effectively isolates heat transfer from the inner substrate, preventing heat deformation of the rotating shaft and further ensuring the uniformity of the bearing clearance. The mounting shell integrates the air supply and temperature control structure, making the entire device compact, reducing the layout of external pipelines, lowering installation difficulty and space occupation, and improving the device's integration and practicality. Furthermore, the layered structure design effectively reduces heat transfer, preventing temperature fluctuations from affecting the overall bearing performance, extending the service life of the air bearing, and reducing maintenance costs. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the overall device in the air bearing device of the present invention; Figure 2 This is a schematic diagram showing the location of the air supply pipeline and air supply structure in an air bearing device according to the present invention. Figure 3This is a schematic diagram showing the location of the temperature control pipeline and temperature control structure in an air bearing device according to the present invention; Figure 4 This is a schematic diagram showing the position of the air flotation film in an air flotation bearing device according to the present invention; Figure 5 This is a schematic cross-sectional view of the bearing base in an air-floating bearing device according to the present invention. Figure 6 This is a schematic diagram of the air supply pipeline in an air bearing device according to the present invention; Figure 7 This is a schematic diagram of the temperature control pipeline in an air bearing device according to the present invention; Figure 8 This is a schematic diagram showing the positions of the air supply pipe and the buffer wrapping layer at the outlet end of the air vent in an air bearing device according to the present invention.

[0016] In the diagram: 100, rotating shaft; 110, heat insulation cylinder; 200, bearing base; 210, inner base; 220, heat insulation layer; 230, outer base; 231, temperature control passage; 240, air supply pipeline; 241, ventilation groove; 242, air supply pipe body; 243, buffer wrapping layer; 250, temperature control pipeline; 300, mounting shell; 310, air supply structure; 320, temperature control structure; 400, air flotation membrane. Detailed Implementation

[0017] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0018] like Figure 1 and Figure 2 As shown, an air bearing device includes: a rotating shaft 100, a bearing base 200, and a mounting shell 300; The rotating shaft 100 is the core rotating component of the device, used to transmit power and realize high-speed rotation. In order to prevent the rotating shaft 100 from deforming due to temperature during operation, which would affect the stability of the bearing clearance, a heat insulation cylinder 110 is fixedly installed on the rotating shaft 100. The outer wall of the heat insulation cylinder 110 is flush with the outer wall of the rotating shaft 100 to ensure that the clearance between the rotating shaft 100 and the bearing base 200 is uniform and to avoid uneven thickness of the air flotation film 400 due to the protrusion or depression of the heat insulation cylinder 110. like Figure 5As shown, the bearing base 200, as the core component supporting the suspension of the rotating shaft 100, adopts a layered structure design, specifically including an inner base 210, a heat insulation layer 220, and an outer base 230. The inner base 210, heat insulation layer 220, and outer base 230 are coaxially arranged outward along the axial direction of the rotating shaft 100. The outer base 230 is made of a material with a low coefficient of thermal expansion, and its main function is to provide stable support and constraint for the entire bearing base 200, preventing significant deformation during temperature changes. The inner base 210 is made of a material with a high coefficient of thermal expansion. The inner substrate 210 is equipped with an air supply pipe 240 and a temperature control pipe 250. When the bearing substrate 200 is heated, the inner substrate 210 will undergo slight thermal expansion due to the use of a material with a high coefficient of thermal expansion. Since its outer side is tightly wrapped and constrained by the outer substrate 230 with a low coefficient of thermal expansion, the outward expansion tendency is limited by the outer substrate 230. Therefore, the inner substrate 210 can only produce uniform inward radial deformation, which in turn causes a slight reduction in the inner diameter of the inner substrate 210, thereby adjusting the bearing clearance and meeting the requirements for the thickness of the air flotation film 400 under different working scenarios. like Figure 2 and Figure 3 As shown, the mounting shell 300 is equipped with an air supply structure 310 and a temperature control structure 320. The air supply structure 310 is connected to the air supply pipeline 240 of the inner substrate 210, and is used to continuously supply compressed air at a stable pressure to the air supply pipeline 240 to provide an air source guarantee for the formation of the air flotation film 400. The temperature control structure 320 is connected to the temperature control pipeline 250 of the inner substrate 210, and is used to control the temperature of the medium in the temperature control pipeline 250, thereby achieving precise temperature adjustment of the inner substrate 210, providing temperature support for the thermal deformation adjustment of the inner substrate 210, and ensuring the accuracy and stability of the bearing clearance adjustment (its accuracy and stability rely on the material's own properties and precise temperature control, and can be monitored by installing relevant sensors. Here, only the deformation principle is described, and the specific structure is not elaborated. The air supply structure 310 and the temperature control structure 320, which can achieve the above functions, are existing conventional technologies, so their specific composition will not be described again). In this embodiment of the invention, by designing the bearing base 200 as a layered structure of an inner base 210, a heat insulation layer 220, and an outer base 230, and selecting materials with high and low coefficients of thermal expansion respectively, and in conjunction with the temperature control of the temperature control pipeline 250, fine adjustment of the bearing clearance is achieved. This solves the problem of fixed clearance in traditional air bearings, which cannot be flexibly adjusted according to working requirements, and significantly improves the adaptability and working stability of the air bearing. At the same time, the heat insulation cylinder 110 installed on the rotating shaft 100 can effectively isolate the heat transfer of the inner base 210, prevent the rotating shaft 100 from deforming due to heat, and further ensure the uniformity of the bearing clearance. The mounting shell 300 integrates the air supply and temperature control structure 320, making the entire device compact, reducing the layout of external pipelines, reducing the installation difficulty and space occupation of the device, and improving the integration and practicality of the device. In addition, the layered structure design can also effectively reduce heat transfer, avoid the impact of temperature fluctuations on the overall performance of the bearing, extend the service life of the air bearing, and reduce maintenance costs.

[0019] like Figure 2 and Figure 3 As shown, the rotating shaft 100, bearing base 200, and mounting housing 300 are coaxial and arranged radially outward along the shaft. The inner wall of the mounting housing 300 is in close contact with the outer wall of the bearing base 200, as shown. Figure 4 As shown, a gap is provided between the bearing base 200 and the outer wall of the rotating shaft 100. This gap is a flotation film 400. Specifically, the rotating shaft 100, bearing base 200, and mounting shell 300 are strictly coaxially aligned to ensure that the rotating shaft 100 does not experience eccentric wobbling during high-speed rotation. This avoids uneven thickness of the flotation film 400, abnormal wear, or vibration caused by eccentricity. The three are radially distributed from the inside to the outside along the axial direction, with the rotating shaft 100 located at the innermost side, followed by the bearing base 200 and the mounting shell 300. The inner wall of the mounting shell 300 is tightly fitted to the outer wall of the bearing base 200, which helps to solidify the bearing base 200. The bearing base 200 has a stabilizing and limiting function, preventing displacement of the bearing base 200 during operation. On the other hand, it can enhance the overall structural strength of the device and reduce vibration transmission. A certain gap is reserved between the bearing base 200 and the outer wall of the rotating shaft 100. This gap is the formation space of the air flotation film 400. When the air supply structure 310 introduces compressed air into the air supply pipeline 240, the compressed air will fill the gap and form a stable air flotation film 400, completely separating the rotating shaft 100 from the bearing base 200. This achieves non-contact suspension rotation of the rotating shaft 100, significantly reducing friction during rotation, reducing component wear, and improving the rotational accuracy and speed of the rotating shaft 100.

[0020] like Figure 2 and Figure 3As shown, the length of the heat insulation cylinder 110 is greater than the length of the bearing base 200, and its two ends extend beyond the two ends of the bearing base 200. That is, the heat insulation cylinder 110 can fully cover the area where the rotating shaft 100 contacts the bearing base 200, and at the same time, it also plays a role in heat insulation protection for the rotating shaft 100 at both ends of the bearing base 200, so as to prevent the heat of the inner base 210 from being transferred to other parts of the device through the rotating shaft 100 and affecting the working stability of the entire device.

[0021] like Figure 6 and Figure 8 As shown, the gas supply pipeline 240 includes a ventilation groove 241 opened in the inner base 210, a solid gas supply pipe body 242, and a buffer wrapping layer 243 wrapped around the gas supply pipe body 242. The air supply pipe body 242 is tightly installed inside the ventilation groove 241, conforming to the shape of the inner wall of the ventilation groove 241. The gap between the two is filled by the buffer wrapping layer 243 on the outside of the air supply pipe body 242, ensuring that there is no gap between the air supply pipe body 242 and the ventilation groove 241, preventing compressed air leakage during transportation, and ensuring stable air supply pressure. At the same time, the buffer wrapping layer 243 also provides expansion and contraction margin, preventing the inner substrate 210 from being rigidly blocked by the air supply pipe body 242 when it expands thermally, ultimately resulting in internal... Regarding the local stress cracking of the substrate 210 and the damage to the air supply pipe 242, it is worth noting that the air supply pipe 242 does not extend to the air outlet at the outlet end of the ventilation groove 241, leaving a certain space. This reduces the processing difficulty of the air outlet of the ventilation groove 241 (because the diameter of the air outlet is very small, and it is difficult to process the embedded solid air supply pipe 242). At the same time, it also ensures that when the inner diameter of the inner substrate 210 is changed, the air supply pipe 242 will not be exposed on the inner wall surface of the inner substrate 210, thus disturbing the air flotation membrane 400. The buffer wrapping layer 243 is made of flexible heat insulation material. On the one hand, it can play a buffering role, reduce the wear of the air supply pipe 242 caused by vibration during operation, protect the air supply pipe 242, and extend its service life. On the other hand, it can play a heat insulation role, prevent the heat of the inner base 210 from being transferred to the air supply pipe 242, prevent the compressed air in the air supply pipe 242 from being heated and expanding, affecting the stability of the air supply pressure, and also prevent the inner base 210 from transferring heat to the rotating shaft 100 through the air in the air supply pipe.

[0022] like Figure 5 and Figure 7As shown, the temperature control pipeline 250 is a microchannel array coaxial with the bearing base 200. Multiple channels are evenly arranged around the axis. Specifically, the temperature control pipeline 250 adopts a microchannel array structure design, with multiple microchannels parallel to each other and all coaxial with the bearing base 200. They are evenly distributed within the inner base 210 around the axis of the rotation shaft 100, forming a ring-shaped pipeline array. Each microchannel has a small diameter, enabling precise temperature control. The even distribution of multiple channels ensures more uniform heating or cooling of the inner base 210, preventing localized overheating or underheating of the inner base 210, which could lead to internal... Uneven deformation of the substrate 210 affects the accuracy of bearing clearance adjustment. The end of the temperature control pipe 250 is connected to the temperature control structure 320 on the mounting shell 300. The temperature control structure 320 achieves precise temperature regulation of the inner substrate 210 by introducing heating or cooling medium into the micro-pipe, thereby controlling the amount of thermal deformation of the inner substrate 210 and achieving the purpose of adjusting the bearing clearance. It is worth noting that the temperature control pipe 250 can be a virtual pipe, that is, the temperature control pipe 250 is a groove opened in the inner substrate 210. If the temperature control pipe 250 needs to be set as a solid pipe, a buffer layer should also be set outside the solid temperature control pipe 250.

[0023] The inner matrix 210 is made of high thermal expansion coefficient materials, including at least beryllium copper, titanium copper alloy, and austenitic stainless steel. Specifically, as the core component for adjusting bearing clearance, the inner matrix 210 needs to have a high thermal expansion coefficient to ensure significant and controllable thermal deformation during temperature changes. Therefore, it is made of high thermal expansion coefficient materials such as beryllium copper, titanium copper alloy, or austenitic stainless steel. Beryllium copper has good thermal conductivity, electrical conductivity, and corrosion resistance, and a high thermal expansion coefficient, enabling stable thermal deformation during temperature changes. It also has high mechanical strength and can withstand certain stresses. Titanium copper alloy has excellent wear resistance and high temperature resistance, a stable thermal expansion coefficient, and uniform deformation, making it suitable for long-term high-speed operation. Austenitic stainless steel has good corrosion resistance and toughness, a high thermal expansion coefficient, and excellent processing performance, facilitating the forming of the inner matrix 210 and the installation of pipelines, thus meeting the usage requirements of different working scenarios.

[0024] The outer matrix 230 is made of low thermal expansion coefficient materials, including at least Invar alloy and pressureless sintered silicon carbide. Specifically, as a constraint and support component of the inner matrix 210, the outer matrix 230 needs to have a low thermal expansion coefficient to ensure that it does not deform significantly during temperature changes, thereby effectively constraining the outward expansion of the inner matrix 210 and causing it to only undergo uniform inward radial deformation. Invar alloy is a low thermal expansion coefficient alloy with an extremely low thermal expansion coefficient. It hardly undergoes thermal deformation within a certain temperature range and has good mechanical strength and toughness, providing stable constraint and support for the inner matrix 210. Pressureless sintered silicon carbide is a ceramic material that not only has a low thermal expansion coefficient but also excellent high temperature resistance, wear resistance, and corrosion resistance, enabling it to adapt to the high-temperature environment during bearing operation. At the same time, it has high mechanical strength and can effectively withstand the pressure brought by the expansion of the inner matrix 210, ensuring the structural stability of the outer matrix 230.

[0025] The heat insulation layer 220 is made of the same material as the outer substrate 230, and its inner wall is coated with a silver coating. Specifically, the heat insulation layer 220, as an insulating component between the inner substrate 210 and the outer substrate 230, is made of the same low coefficient of thermal expansion material as the outer substrate 230. This ensures that the coefficients of thermal expansion of the heat insulation layer 220 and the outer substrate 230 are consistent, preventing stress caused by the difference in their coefficients of thermal expansion during temperature changes, which could lead to separation or damage between the heat insulation layer 220 and the outer substrate 230, thus protecting the integrity of the bearing base 200. For structural stability, a silver coating is provided on the inner wall of the insulation layer 220, that is, the side in contact with the inner substrate 210. Silver has excellent heat reflection properties, which can reflect most of the heat generated by the inner substrate 210 back, reducing the heat transfer through the insulation layer 220 to the outer substrate 230 and the mounting shell 300. This ensures that the outer substrate 230 is always in a stable temperature state, preventing the outer substrate 230 from deforming due to heat. At the same time, it can also reduce heat loss, improve the temperature control efficiency of the temperature control structure 320, and reduce energy consumption.

[0026] like Figure 2 and Figure 4 As shown, a temperature regulating passage 231 is provided on the outer substrate 230. The air inlet of the temperature regulating passage 231 is connected to the air supply structure 310, and the mounting shell 300 at the corresponding position of its air outlet is a hollow structure. During operation, the air supply structure 310 provides air that is discharged from the hollow part of the mounting shell 300 through the temperature regulating passage 231. During this process, the air will exchange heat with the outer substrate 230, taking away the excess heat on the surface of the outer substrate 230, so that the temperature of the outer substrate 230 gradually approaches the temperature of the outside air, ensuring that the outer substrate 230 is always in a stable temperature state and avoiding deformation due to temperature fluctuations.

[0027] A method for adjusting the bearing clearance of an air bearing device includes the following steps: Step 1: Start the air supply structure 310 and introduce compressed air into the air supply pipeline 240. The compressed air is discharged through the air outlet at the outlet end of the air supply pipe 242 and the air channel 241 to the gap between the bearing base 200 and the rotating shaft 100, forming a stable air flotation film 400, which suspends the rotating shaft 100 and achieves a non-contact state with the inner wall of the bearing base 200. At the same time, the air supply structure 310 branches into the temperature regulation passage 231 to introduce air, which carries away the excess heat of the outer base 230 and makes the temperature of the outer base 230 gradually approach the air temperature. Step 2: When it is necessary to adjust the bearing clearance and change the thickness of the air flotation film 400, taking the reduction of the bearing clearance as an example, firstly, the temperature control structure 320 is activated, and the temperature control pipeline 250 is used to uniformly control the temperature of the inner substrate 210 of the bearing substrate 200. In the initial stage, the inner substrate 210 is heated with low heat power. The silver coating on the inner wall of the heat insulation layer 220 reflects the heat, reducing the heat transfer to the heat insulation layer 220 and the outer substrate 230, and avoiding thermal deformation of the outer substrate 230. Step 3: The gap size of the air flotation membrane 400 is monitored in real time through the external control system and sensor system. Combined with the preset bearing gap standard, the temperature control parameters of the temperature control structure 320 are adjusted to change the degree of heating of the inner substrate 210. With the help of the high thermal expansion coefficient of the inner substrate 210, it is constrained by the low thermal expansion coefficient of the outer substrate 230 to produce uniform inward radial deformation, gradually reducing the inner diameter of the inner substrate 210, and thus fine-tuning the bearing gap. The aforementioned external control system and sensor system may include an eddy current displacement sensor with its probe facing the air flotation film 400 area between the bearing base 200 and the rotating shaft 100 to monitor the thickness of the air flotation film gap; a resistance temperature sensor that is attached to the outer walls of the inner base 210 and the outer base 230 to monitor the temperature of the inner base 210 and the outer base 230; and a high-precision temperature sensor that is installed at the inlet and outlet ends of the temperature control pipeline 250 to monitor the temperature of the temperature control pipeline. Step 4: During the gap adjustment process, the air supply pressure of the air supply structure 310 is kept stable to ensure the load-bearing capacity and stability of the air flotation membrane 400. At the same time, air is continuously introduced through the temperature regulation passage 231 to ensure that the temperature of the outer substrate 230 is always close to the air temperature, so as to avoid temperature fluctuations affecting the outer substrate 230 and thus affecting the gap adjustment accuracy. Meanwhile, the heat insulation effect of the heat insulation cylinder 110 is monitored to prevent the rotating shaft 100 from being deformed by the heat of the inner substrate 210. Step 5: When the bearing clearance is detected to reach the preset standard, reduce the power of the temperature control structure 320 to maintain the same heating and cooling efficiency of the inner substrate 210. At the same time, maintain the air supply of the air supply structure 310 and the temperature adjustment passage 231 to keep the adjusted bearing clearance stable.

[0028] The main principle of this application is as follows: the outer matrix 230 is a rigid constraint body relative to the inner matrix 210. When the inner matrix 210 is heated, its outward expansion tendency is restricted by the outer matrix 230. According to the law of conservation of energy and the mechanics of materials, the expansion energy of the inner matrix 210 will be converted into uniform inward radial contraction energy. Since the inner matrix 210 is a ring structure and the outer matrix 230 is uniformly constrained, there is no local deviation in the contraction deformation.

[0029] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An air bearing device, characterized in that, include: Rotating shaft (100), bearing base (200) and mounting housing (300); A heat insulation cylinder (110) is provided on the rotating shaft (100), and the outer wall of the heat insulation cylinder (110) is on the same plane as the outer wall of the rotating shaft (100); The bearing base (200) includes an inner base (210), a heat insulation layer (220), and an outer base (230). The inner base (210), the heat insulation layer (220), and the outer base (230) are arranged sequentially outward along the axis. The outer base (230) is made of a material with a low coefficient of thermal expansion, and the inner base (210) is made of a material with a high coefficient of thermal expansion. An air supply pipe (240) and a temperature control pipe (250) are arranged inside the inner base (210). When the bearing base (200) is heated, the inner base (210) expands slightly due to heat. Its outward expansion is constrained by the low-expansion outer base (230), resulting in only uniform inward radial deformation, which causes a slight reduction in the inner diameter of the inner base (210). The mounting housing (300) is provided with an air supply structure (310) and a temperature control structure (320), which are used to supply air to the air supply pipeline (240) and to control the temperature of the temperature control pipeline (250), respectively.

2. The air bearing device according to claim 1, characterized in that: The rotating shaft (100), bearing base (200) and mounting shell (300) are coaxial and arranged radially outward along the axis. The inner wall of the mounting shell (300) is in close contact with the outer wall of the bearing base (200). A gap is provided between the bearing base (200) and the outer wall of the rotating shaft (100), and this gap is an air flotation film (400).

3. The air bearing device according to claim 1, characterized in that: The length of the heat insulation cylinder (110) is greater than the length of the bearing base (200), and its two ends extend beyond the two ends of the bearing base (200).

4. The air bearing device according to claim 1, characterized in that: The gas supply pipeline (240) includes a ventilation groove (241) opened in the inner base (210), a solid gas supply pipe body (242), and a buffer wrapping layer (243) wrapped around the gas supply pipe body (242). The gas supply pipe body (242) is tightly arranged in the ventilation groove (241), conforming to the shape of the inner wall of the ventilation groove (241), but does not extend to the air outlet at the outlet end of the ventilation groove (241).

5. The air bearing device according to claim 1, characterized in that: The temperature control pipeline (250) is a micro-pipe array coaxial with the bearing base (200), with multiple pipelines evenly arranged around the axis.

6. The air bearing device according to claim 1, characterized in that: The high thermal expansion coefficient material selected for the inner matrix (210) includes at least beryllium copper, titanium copper alloy and austenitic stainless steel.

7. The air bearing device according to claim 1, characterized in that: The material selected for the outer substrate (230) is a low thermal expansion coefficient material, including at least Invar alloy and pressureless sintered silicon carbide.

8. The air bearing device according to claim 1, characterized in that: The heat insulation layer (220) is made of the same material as the outer substrate (230), and its inner wall is provided with a silver coating.

9. The air bearing device according to claim 1, characterized in that: A temperature regulating passage (231) is provided on the outer substrate (230). The air inlet of the temperature regulating passage (231) is connected to the air supply structure (310), and the mounting shell (300) at the corresponding position of its air outlet is a hollow structure. When working, the air supply structure (310) provides air through the temperature regulating passage (231) and discharges it from the hollow part of the mounting shell (300) to make the temperature of the outer substrate (230) approach the air temperature.

10. A method for adjusting the bearing clearance of an air bearing device, characterized in that: The air bearing device according to any one of claims 1 to 9 is used, comprising the following steps: S1: Start the air supply structure (310) and introduce compressed air into the air supply pipeline (240). The compressed air is discharged through the air outlet of the air supply pipe body (242) and the air outlet of the air channel (241) to the gap between the bearing base (200) and the rotating shaft (100), forming a stable air flotation film (400) to suspend the rotating shaft (100). At the same time, the air supply structure (310) branches into the temperature regulation passage (231) to introduce air. S2: When it is necessary to adjust the bearing clearance and change the thickness of the air flotation film (400), the temperature control structure (320) is activated first. The temperature control pipeline (250) is used to uniformly control the temperature of the inner substrate (210) of the bearing substrate (200). In the initial stage, the inner substrate (210) is heated with low heat power. The silver coating on the inner wall of the insulation layer (220) reflects the heat, reducing the heat transfer to the insulation layer (220) and the outer substrate (230) and avoiding thermal deformation of the outer substrate (230). S3: Real-time monitoring of the gap size of the air flotation film (400), combined with the preset bearing gap standard, adjusting the temperature control parameters of the temperature control structure (320), changing the degree of heating of the inner substrate (210), and taking advantage of the high thermal expansion coefficient of the inner substrate (210), causing it to produce uniform inward radial deformation under the constraint of the low thermal expansion coefficient outer substrate (230), gradually reducing the inner diameter of the inner substrate (210), and thus fine-tuning the bearing gap; S4: During the gap adjustment process, the air supply pressure of the air supply structure (310) is kept stable to ensure the load-bearing capacity and stability of the air flotation membrane (400). At the same time, air is continuously introduced through the temperature regulation channel (231) to ensure that the temperature of the outer substrate (230) is always close to the air temperature, so as to avoid temperature fluctuations affecting the outer substrate (230) and thus affecting the gap adjustment accuracy. At the same time, the heat insulation effect of the heat insulation cylinder (110) is monitored to prevent the rotating shaft (100) from being deformed by the heat of the inner substrate (210). S5: When the bearing clearance is detected to reach the preset standard, reduce the power of the temperature control structure (320) to keep the heating efficiency of the inner substrate (210) consistent with the natural cooling efficiency, while maintaining the air supply of the air supply structure (310) and the temperature adjustment passage (231) so that the adjusted bearing clearance remains stable.

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