A high-damping tilting pad gas bearing

Abstract

The present invention provides a high-damping tilting pad gas bearing, which relates to the technical field of gas bearings, solves the principle problem of low damping of existing gas bearings, and can effectively improve the system stability. The device of the invention comprises: a tilting pad bearing body, a top foil, a wave foil, a magnet, a piezoelectric ceramic (PZT), a spring, and a screw. The tilting pad bearing body is processed by wire cutting to obtain a tilting pad, a magnification hinge, and a groove for placing the spring and the PZT. The rigid part of the magnification hinge is fixedly connected to the magnet and faces the tilting pad support. The spring is horizontally placed in the groove to support one side of the magnification hinge and apply a pre-displacement to the hinge. The PZT is at the same horizontal level as the spring and supports the other side of the tilting pad support. The screw abuts against the PZT to make the PZT in close contact with the hinge and adjust the initial position of the magnification hinge. The wave foil and the top foil are pressed, with one end fixed on the surface of the tilting pad and the other end free. By controlling the supply voltage of the PZT, its expansion and contraction length is changed, the moving direction and magnitude of the magnification hinge are adjusted, that is, the distance between the magnet and the tilting pad support is changed, the magnetic field strength is affected, and further the mechanical energy of the tilting pad vibration caused by the eccentric rotor vibration is converted into the eddy current heat energy of the tilting pad support, the damping characteristics of the bearing are adjusted, and the stability of the system is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of radial gas bearings, and particularly to a high-damping tilting pad gas bearing. Background Art

[0002] A tilting pad gas bearing is a bearing that adaptively changes the position of the tilting pads according to the motion trajectory of the rotor and uses the gas dynamic pressure effect to support the rotor load. It has the advantages of no pollution, low energy consumption and high output, and good operation in extreme environments, and is widely used in equipment such as air cycle machines, oil-free turbochargers, and fuel cell air compressors. When the rotor is in a super-high-speed working state, the stiffness of the compressed gas film will be greater than the stiffness of the tilting pad structure, resulting in the stiffness and damping of the tilting pads directly supporting the working process of the rotor. However, the tilting pads and the bearing sleeve are an integral structure, and the damping of the bearing is insufficient to suppress the high-frequency synchronous vibration of the system. Moreover, the rigid tilting pad surface adjusted with the rotor cannot fully accommodate the compressed gas, which limits the bearing capacity.

[0003] In traditional foil gas bearings, the top foil and the wave foil are a flexible structure with stiffness and damping, which can effectively accommodate compressed gas, making the foil gas bearing have excellent bearing capacity. However, the cross stiffness of the foil gas bearing has a negative damping effect on the rotor system, exciting the sub-synchronous vibration of the rotor. The friction damping between the foil structures cannot suppress this sub-synchronous vibration, which will limit the development of the rotor system towards higher speeds. Summary of the Invention

[0004] In view of the above technical deficiencies, the present invention patent application provides a high-damping tilting pad gas bearing to solve the technical problem of insufficient damping of radial gas bearings and improve the stability of the system. The many technical effects that can be produced by the preferred technical solutions among the many technical solutions provided by the present invention are described in detail below.

[0005] To achieve the above technical purpose, the present invention provides the following technical solutions: A double high-damping tilting pad gas bearing includes a tilting pad bearing body, a top foil, a wave foil, a magnet, a piezoelectric ceramic PZT, a spring, and a screw.

[0006] Further, the tilting pad bearing body is obtained by wire cutting to have tilting pads, magnifying hinges, slots for placing springs, and slots for placing PZTs evenly distributed in the circumferential direction.

[0007] Furthermore, the tilting pad is composed of a tilting pad body, a vertical part of the tilting pad support, and a horizontal part of the tilting pad support. The magnifying hinge is composed of a flexible part of the magnifying hinge and a rigid part of the magnifying hinge. The groove for placing the spring and the groove for placing the PZT are at the same level and are relatively distributed on both sides of the magnifying hinge. The two magnifying hinges are at the same level and are relatively distributed on both sides of the vertical part of the tilting pad support. The thickness of the horizontal part of the tilting pad support is small, and there is a slot hole below it, so that the tilting pad can move along the direction of the vertical part of the tilting pad support after bearing a certain load. The rigid part of the magnifying hinge is in a free state and can rotate around the flexible part of the magnifying hinge as the center.

[0008] Furthermore, the rigid part of the magnifying hinge is fixedly connected to the magnet, and is directly opposite to the vertical part of the tilting pad support. There is a certain gap between the fixedly connected magnet and the vertical part of the tilting pad support, and the surface of the magnet does not contact and affect the movement of the tilting pad.

[0009] Furthermore, the spring is in the groove for placing the spring and contacts one side of the rigid part of the magnifying hinge, applying a pre-displacement to the hinge, so that the distance between the fixed magnet and the vertical part of the tilting pad support reaches the minimum value.

[0010] Furthermore, the PZT is in the groove for placing the PZT, and is at the same level as the spring, and contacts one side of the rigid part of the magnifying hinge. The screw presses against the PZT to make the PZT in close contact with the surface of the rigid part of the magnifying hinge, adjusting the initial position of the magnifying hinge.

[0011] Furthermore, the top foil and the wave foil are formed by die pressing. One end of the top foil and the wave foil is fixed on the surface of the tilting pad body together, and the other end is free. There is a lubricating metal coating on the surface of the top foil, which can reduce the wear of the top foil during the start-stop process of the rotor.

[0012] Furthermore, multiple vertical parts of the tilting pad support and horizontal parts of the tilting pad support can be connected below the tilting pad body. The magnifying hinge of the new type of high-damping tilting pad gas bearing can act on the vertical part of the tilting pad support unidirectionally.

[0013] Furthermore, the PZT is used to control the movement of the magnifying hinge. The new type of high-damping tilting pad gas bearing can also be realized by other methods, such as electro-controlled moving materials such as magnetostrictive materials and shape memory alloy materials.

[0014] Furthermore, the top foil and wave foil can be changed to porous tiles to achieve the effect of hybrid hydrostatic and hydrodynamic gas suspension. The surface of the tilting pad of the new type of high-damping tilting pad gas bearing has grooves with a certain depth for gas flow. The porous tiles are adhered to the surface of the tilting pad. Threaded holes are opened on the axial side of the tilting pad to connect the grooves, and threaded pipes are installed in the threaded holes. The gas supply pipe is connected to the hollow threaded pipe to supply gas to the grooves in the tilting pad body.

[0015] The technical solution adopted by the present invention has the following beneficial effects: The present invention converts the mechanical vibration of the tilting pad caused by the rotor vibration into the eddy current heat energy generated by the tilting pad cutting the magnetic induction line, improving the damping effect of the system, and this damping will be more obvious during high-frequency vibration and can also be adjusted according to actual needs. It is mainly reflected that the vertical part of the tilting pad support in the working state cuts the magnetic induction line generated by the magnet to generate eddy current, consuming the kinetic energy of the tilting pad. The magnet is fixedly connected to the rigid end of the amplification hinge. The rigid end of the amplification hinge can move away from or close to the vertical part of the tilting pad support under the control of the spring and PZT, changing the magnetic field intensity at the vertical part of the tilting pad support, and then adjusting the size of the eddy current heat energy; The top foil and wave foil fixed on the surface of the tilting pad can bear the impact vibration of the rotor in the form of deformation and accommodate the compressed gas to support the rotor load, enabling the present invention to obtain both high load-carrying capacity and high damping characteristics. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0017] Figure 1 An isometric view of a high-damping tilting pad gas bearing provided by an embodiment of the present invention.

[0018] Figure 2 An exploded view of a high-damping tilting pad gas bearing provided by an embodiment of the present invention.

[0019] Figure 3 A front view of a high-damping tilting pad gas bearing provided by an embodiment of the present invention.

[0020] Figure 4 A partial cross-sectional view of a high-damping tilting pad gas bearing provided by an embodiment of the present invention.

[0021] Figure 5 A partial enlarged view of a high-damping tilting pad gas bearing provided by an embodiment of the present invention.

[0022] Figure 6 An explosion diagram of other types of structures of a high-damping tilting pad gas bearing provided by an embodiment of the present invention. Embodiment

[0023] To make the objectives, technical solutions and advantages of the present invention clearer, the technical solutions of the present invention will be described in detail below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts fall within the scope of protection of the present invention.

[0024] In the description of the present invention, it should be noted that unless otherwise specified, the meaning of "a plurality of" is two or more; the orientation or positional relationship indicated by terms such as "upper", "lower", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be construed as a limitation of the present invention. In addition, terms such as "main" and "auxiliary" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance.

[0025] In the description of the present invention, it should also be noted that unless otherwise clearly defined and limited, the term "preload" should be understood in a broad sense. For example, it can be a pre-applied load before installation, or the effect of the structure form after installation is the same as the pre-applied one. For those of ordinary skill in the art, the specific meaning of the above terms in the present invention can be understood according to specific circumstances.

[0026] The present invention patent provides a high-damping tilting pad gas bearing, which includes a tilting pad bearing body (1), a top foil (2), a wave foil (3), a magnet (4), a piezoelectric ceramic PZT (5), a spring (6), and a screw (7).

[0027] The tilting pad bearing body (1) is obtained by wire electrical discharge machining to have evenly distributed tilting pads (14), magnifying hinges (13), a groove (11) for placing a spring, and a groove (12) for placing a PZT along the circumferential direction.

[0028] The tilting pad (14) consists of a tilting pad body (143), a vertical part (142) of the tilting pad support, and a horizontal part (141) of the tilting pad support. One tilting pad body (143) is supported by multiple vertical parts (142) and horizontal parts (141) of the tilting pad support. The end of the vertical part (142) of the tilting pad support has a smaller size, enabling it to transfer the acting force of the tilting pad body but not the moment. The amplification hinge (13) consists of a flexible part (131) and a rigid part (132) of the amplification hinge. The flexible part (131) of the amplification hinge has a smaller size and is connected to the bearing sleeve, allowing the rigid part (132) of the amplification hinge in the free state to rotate to a certain extent around the flexible part (131) of the amplification hinge. The groove (11) for placing the spring and the groove (12) for placing the PZT are at the same level and are relatively distributed on both sides of the amplification hinge (13), and their positions are at a certain distance from the flexible part (131) of the amplification hinge, magnifying the energized displacement of the PZT to the rigid part (132) of the amplification hinge by leverage. Two amplification hinges (13) are at the same level and are relatively distributed on both sides of the vertical part (142) of the tilting pad support. The horizontal part (141) of the tilting pad support has a smaller thickness and has a slot hole below, enabling the tilting pad (14) to move along the direction of the vertical part (142) of the tilting pad support after bearing a certain load.

[0029] The rigid part (132) of the amplification hinge is fixedly connected to the magnet (4), and is directly opposite to the vertical part (142) of the tilting pad support. There is a certain gap between the fixedly connected magnet (4) and the vertical part (142) of the tilting pad support, and the surface of the magnet (4) does not contact and affect the movement of the tilting pad (14).

[0030] The spring (6) is in the groove (11) for placing the spring and contacts one side of the rigid part (132) of the amplification hinge, applying a pre - displacement to the hinge, so that the distance between the fixed magnet (4) and the vertical part (142) of the tilting pad support reaches the minimum value.

[0031] The PZT (5) is in the groove (12) for placing the PZT, and is at the same level as the spring (6), and contacts one side of the rigid part (132) of the amplification hinge. The screw (7) abuts against the PZT (5), making the PZT (5) in close contact with the surface of the rigid part (132) of the amplification hinge to adjust the initial position of the amplification hinge (13).

[0032] The top foil (2) and the wave foil (3) are subjected to a certain heat treatment process after being pressed by a mold, so that the foil structure has good ductility and elastic stiffness. One end of the top foil and the wave foil is fixed on the surface of the tilting pad body (143), and the other end is free. The surface of the top foil has a lubricating metal coating, which can reduce the wear of the top foil during the start - stop process of the rotor.

[0033] As an alternative embodiment, the amplification hinge (13) can act on the vertical part (142) of the tilting pad bearing unidirectionally.

[0034] As an alternative embodiment, PZT (5) is used to realize the function of controlling the movement of the amplification hinge (13). The new type of high-damping tilting pad gas bearing can also be realized by other means, such as magnetostrictive materials, shape memory alloy materials and other materials with electrically controlled movement.

[0035] As an alternative embodiment, the top foil (2) and the wave foil (3) can be changed to a porous pad (8) to achieve the effect of hybrid hydrostatic and hydrodynamic suspension. The surface of the tilting pad body (143) of the new type of high-damping tilting pad gas bearing is provided with grooves with a certain depth for gas flow. The porous pad (8) is adhered to the surface of the tilting pad body (143). Threaded holes are provided on the axial side of the tilting pad to connect the grooves. The threaded pipe is installed in the threaded hole, and the air supply pipe is connected to the hollow threaded pipe to supply gas to the grooves in the tilting pad body (143).

[0036] The above are only specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed by the present invention, and all of them should be covered by the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims

1. A high-damping tilting pad gas bearing, characterized in that, It includes a tilting pad bearing body (1), a top foil (2), a wave foil (3), a magnet (4), a piezoelectric ceramic PZT (5), a spring (6), and a screw (7); the tilting pad bearing body (1) is processed by wire cutting to obtain evenly distributed tilting pads (14), amplification hinges (13), a groove (11) for placing the spring, and a groove (12) for placing the PZT along the circumferential direction. The tilting pad (14) is composed of a tilting pad body (143), a vertical part (142) of the tilting pad support, and a horizontal part (141) of the tilting pad support. The amplification hinge (13) is composed of a flexible part (131) of the amplification hinge and a rigid part (132) of the amplification hinge; the groove (11) for placing the spring and the groove (12) for placing the PZT are at the same level and are relatively distributed on both sides of the amplification hinge (13); the two amplification hinges (13) are at the same level and are relatively distributed on both sides of the vertical part (142) of the tilting pad support; the horizontal part (141) of the tilting pad support has a smaller thickness and there is a slot hole below it, so that the tilting pad (14) can move along the direction of the vertical part (142) of the tilting pad support after bearing a certain load; the rigid part (132) of the amplification hinge is in a free state and can rotate around the flexible part (131) of the amplification hinge. The rigid part (132) of the amplification hinge is fixedly connected to the magnet (4) and is directly opposite to the vertical part (142) of the tilting pad support. There is a certain gap between the fixedly connected magnet (4) and the vertical part (142) of the tilting pad support; the spring (6) is in the groove (11) for placing the spring and contacts one side of the rigid part (132) of the amplification hinge, applying a pre-displacement to the hinge, so that the distance between the fixed magnet (4) and the vertical part (142) of the tilting pad support reaches the minimum value; the PZT (5) is in the groove (12) for placing the PZT and is at the same level as the spring (6), and contacts one side of the rigid part (132) of the amplification hinge. The screw (7) presses against the PZT (5) to make the PZT (5) in close contact with the surface of the rigid part (132) of the amplification hinge, adjusting the initial position of the amplification hinge (13). The rigid end of the amplification hinge moves away from or close to the vertical part of the tilting pad support under the control of the spring and the PZT, changing the magnetic field strength where the vertical part of the tilting pad support is located, and further adjusting the magnitude of the eddy current heat energy.

2. The high-damping tilting pad gas bearing according to claim 1, wherein The top foil (2) and the wave foil (3) are formed by die pressing. One end of the top foil and the wave foil is fixed on the surface of the tilting pad body (143), and the other end is free. The surface of the top foil has a lubricating metal coating, which can reduce the wear of the top foil during the start-stop process of the rotor.

3. The high-damping tilting pad gas bearing according to claim 1, characterized in that, Multiple vertical parts (142) of the tilting pad support and horizontal parts (141) of the tilting pad support can be connected below the tilting pad body (143). The amplification hinge (13) of the new type of high-damping tilting pad gas bearing can act on the vertical part (142) of the tilting pad support unidirectionally.

4. The high-damping tilting pad gas bearing according to claim 1, wherein The top foil (2) and wave foil (3) can be changed to a porous tile (8) to achieve the effect of static and dynamic pressure mixed gas suspension. A groove with a certain depth is formed on the surface of the tilting pad body (143) of the new type of high-damping tilting pad gas bearing for gas flow. The porous tile (8) is adhered to the surface of the tilting pad body (143). A threaded hole connecting groove is formed on the axial side of the tilting pad, and a threaded tube is installed in the threaded hole. The gas supply pipe is connected to the hollow threaded tube to supply gas to the groove in the tilting pad body (143).

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