A radial gas dynamic pressure bearing and electric machine

Abstract

The application provides a radial gas dynamic pressure bearing and a motor, and the radial gas dynamic pressure bearing comprises a top foil and a first layer wave foil, the top foil comprises a top foil bearing section, the first layer wave foil comprises a first layer wave foil flat section, a first layer wave foil support section one and a first layer wave foil support section two, the radial outer ends of the first layer wave foil support section one and the first layer wave foil support section two are fixed, the radial inner ends of the two protrude towards the top foil bearing section to be connected with the top foil bearing section and support the top foil bearing section, and the radial inner end of the first layer wave foil support section one and the radial inner end of the first layer wave foil support section two protrude towards each other and are spaced by a preset distance greater than 0. According to the application, a double wave peak structure is formed, the deformation of the flat foil between the two wave peaks of the wave foil and the contact area of the flat foil and the wave foil are increased, the stiffness of the wave peak position is homogenized, the wear is reduced, and the overall service life is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of gas bearing, in particular to a radial gas dynamic pressure bearing and motor. BACKGROUND

[0002] The gas dynamic pressure bearing has the advantages of high precision, no pollution, high speed and simple structure, and has been widely used in high-speed rotating machinery such as oil-free turbine of aero-engine, cryogenic expander and air cycle machine of an airplane.

[0003] CN 211398261 U proposes a dynamic pressure gas radial bearing, which comprises a bearing shell (20) having a shell inner wall for enclosing a hollow inner cavity accommodating a rotor (10); a top foil (30) arranged in the hollow inner cavity; a wave foil (40) having a plurality of wave segments (42) supported between the top foil (30) and the shell inner wall; at least one wave segment (42) in the plurality of wave segments (42) is in surface contact with the top foil (30) and the shell inner wall. However, the contact surface between the wave foil and the top foil is a flat segment, which has a large stiffness and is prone to wear.

[0004] CN 112648283 A proposes a dynamic pressure radial gas bearing. It comprises a bearing seat (1), the inner circumferential side of the bearing seat is provided with a flat foil (2), and a plurality of wave foil groups (3) are further arranged between the bearing seat (1) and the flat foil (2), characterized in that any one of the wave foil groups (3) comprises two high-arch foils (31) and one low-arch foil (32), the distance from the foil arch of the high-arch foil (31) to the flat foil (2) is less than the distance from the foil arch of the low-arch foil (32) to the flat foil (2). However, it is composed of a single layer of arch foil + a single layer of flat foil structure, the bearing stiffness is small, the bearing capacity is poor, and the damping is small and prone to wear.

[0005] In summary, the original technical solution of the dynamic pressure gas floating radial bearing has the problems of difficult bearing preparation and assembly, poor consistency, easy wear, poor bearing capacity, etc.

[0006] Since the foil gas dynamic pressure bearing in the prior art has the technical problems of easy wear and poor bearing capacity, the present application designs a radial gas dynamic pressure bearing and motor. SUMMARY

[0007] Therefore, the technical problem to be solved by the present application is to overcome the defects of the foil gas dynamic pressure bearing in the prior art, such as easy wear and poor bearing capacity, so as to provide a radial gas dynamic pressure bearing and motor.

[0008] In order to solve the above problems, the present application provides a radial gas dynamic pressure bearing, which comprises:

[0009] The top foil and the first layer wave foil, the first layer wave foil is arranged at the outer periphery of the top foil, so as to be able to exert a supporting force on the top foil, the top foil includes a top foil bearing section, the first layer wave foil includes a first layer wave foil flat section, a first layer wave foil support section one and a first layer wave foil support section two, the first layer wave foil flat section is arranged between the top foil bearing section, the first layer wave foil support section one and the first layer wave foil support section two are both located between the first layer wave foil flat section and the top foil bearing section, the radial outer end of the first layer wave foil support section one and the first layer wave foil support section two are both fixed, the radial inner end of both is protruding towards the direction of the top foil bearing section to be connected with the top foil bearing section to support the top foil bearing section, and the radial inner end of the first layer wave foil support section one and the radial inner end of the first layer wave foil support section two are protruding towards each other and spaced apart by a preset distance greater than 0.

[0010] In some embodiments,

[0011] The radial outer end of the first layer wave foil support section one is a first fixed end, and the radial inner end is a first free end protruding towards the direction of the top foil bearing section, the first free end can be connected with the top foil bearing section when the top foil bearing section bears a load, and the first free end can be connected with or not connected with the top foil bearing section when the top foil bearing section does not bear a load.

[0012] The radial outer end of the first layer wave foil support section two is a second fixed end, and the radial inner end is a second free end protruding towards the direction of the top foil bearing section, the second free end can be connected with the top foil bearing section when the top foil bearing section bears a load, and the second free end can be connected with or not connected with the top foil bearing section when the top foil bearing section does not bear a load.

[0013] In some embodiments,

[0014] The first layer wave foil support section one further includes a first intermediate end located between the first free end and the first fixed end, and the part between the first intermediate end and the first free end is a first flat section connected with the top foil bearing section, and the first layer wave foil support section two further includes a second intermediate end located between the second free end and the second fixed end, and the part between the second intermediate end and the second free end is a second flat section connected with the top foil bearing section.

[0015] In some embodiments,

[0016] In the projection plane of the axial end surface, the part between the first fixed end and the first intermediate end is an arc-shaped section structure, the first flat section is a straight section abutting the top foil bearing section, the part between the second fixed end and the second intermediate end is an arc-shaped section structure, and the second flat section is a straight section abutting the top foil bearing section.

[0017] In some embodiments,

[0018] In the circumferential direction, the distance between the first free end and the second free end is less than the distance between the first fixed end and the second fixed end.

[0019] The first layer wave foil flat section is an arc section structure or a ring section structure arranged around the outer circumferential wall of the top foil bearing section.

[0020] In some embodiments,

[0021] The first fixed end is fixedly connected to the inner circumferential wall of the first layer wave foil flat section, and the second fixed end is fixedly connected to the inner circumferential wall of the first layer wave foil flat section.

[0022] The first layer wave foil support section one and the first layer wave foil support section two form a first support unit, and a plurality of first support units are arranged on the inner circumferential wall of the first layer wave foil flat section in the circumferential direction, i.e., every two adjacent first support units are arranged at intervals.

[0023] In some embodiments,

[0024] Further comprising a second layer wave foil, the second layer wave foil comprising a second layer wave foil flat section and a second layer wave foil support section, the second layer wave foil flat section being arranged on the outer circumferential wall of the first layer wave foil flat section, the first layer wave foil support section one and the first layer wave foil support section two being arranged on the inner circumferential wall of the first layer wave foil flat section and protruding towards the top foil bearing section, the second layer wave foil support section being arranged on the inner circumferential wall of the second layer wave foil flat section and protruding towards the top foil bearing section, the first layer wave foil support section one being located between the second layer wave foil support section and the top foil bearing section, and the first layer wave foil support section two being located between the second layer wave foil support section and the top foil bearing section.

[0025] In some embodiments,

[0026] One end of the second layer wave foil support section connected to the second layer wave foil flat section is a third fixed end, and the third fixed end is fixedly connected to the second layer wave foil flat section, and the other end of the second layer wave foil support section connected to the second layer wave foil flat section is a fourth fixed end, and the fourth fixed end is fixedly connected to the second layer wave foil flat section, and the structure between the third fixed end and the fourth fixed end is a continuous structure protruding towards the top foil bearing section.

[0027] In some embodiments,

[0028] The second layer wave foil support section is in an arc segment structure in the projection plane of the axial end face; along the radial direction, the radial distance between the first free end and the first fixed end is the arch height H1 of the first layer wave foil support section one, the radial distance between the second free end and the second fixed end is the arch height H2 of the first layer wave foil support section two, the position closest to the top foil bearing section of the second layer wave foil support section is a second layer wave crest end, along the radial direction, the radial distance between the second layer wave crest end and the third fixed end and the radial distance between the second layer wave crest end and the fourth fixed end are equal, both being the arch height H3 of the second layer wave foil support section, and H1>H3, H2>H3.

[0029] In some embodiments,

[0030] H3=0.7H1=0.7H2; or, the first layer wave foil support section two is the air inlet side, and the first layer wave foil support section one is the air outlet side, and H1>H2.

[0031] In some embodiments,

[0032] In the circumferential direction, the second layer wave foil support section is located between the first fixed end and the second fixed end; in the radial direction, the first free end is located between the second layer wave foil support section and the top foil bearing section, and the second free end is located between the second layer wave foil support section and the top foil bearing section.

[0033] In some embodiments,

[0034] The first layer wave foil support section one, the first layer wave foil support section two and the second layer wave foil support section form a second support unit, and a plurality of second support units are arranged at intervals in the circumferential direction.

[0035] In some embodiments,

[0036] Further comprising a top foil fixed section and a first layer wave foil fixed section, one end of the top foil fixed section is connected to the top foil bearing section, and the other end extends outward in the radial direction, one end of the first layer wave foil fixed section is connected to the first layer wave foil flat section, and the other end extends outward in the radial direction, and the part of the top foil fixed section extending outward in the radial direction is fixed to the part of the first layer wave foil fixed section extending outward in the radial direction.

[0037] In some embodiments,

[0038] The second layer wave foil fixed segment is arranged at the same position as the first layer wave foil fixed segment, one end of the second layer wave foil fixed segment is connected with the second layer wave foil flat segment, and the other end extends to the radial outside, and the part of the second layer wave foil fixed segment extending to the radial outside is fixed with the part of the first layer wave foil fixed segment extending to the radial outside.

[0039] The application also provides an electric machine comprising the radial gas dynamic pressure bearing.

[0040] The radial gas dynamic pressure bearing and the electric machine have the following beneficial effects:

[0041] 1. The first layer wave foil support segment is divided into the first layer wave foil support segment one and the first layer wave foil support segment two, the distance between the two is greater than 0, and the two protrude towards the top foil bearing segment, so that the two spaced support ends can form support for the top foil bearing segment, the double wave peak structure is formed, the line contact of the existing single wave peak support is improved to the surface contact of the double wave peak support, the support stiffness of the bearing at the wave peak is reduced, the deformation of the flat foil between the two wave peaks of the wave foil and the contact area of the flat foil and the wave foil are increased, the stiffness of the wave peak position is uniformized, the wear is reduced, the overall life is improved, and the support area is increased, the high-pressure gas end leakage is effectively inhibited, and the service life and the bearing capacity are improved.

[0042] 2. The second layer wave foil is arranged on the outer periphery of the first layer wave foil, the second layer wave foil support segment with an arch height smaller than the first layer wave foil support end one and two effectively forms a support structure for the double-layer wave foil of the top foil bearing segment, and the double-layer structure wave foil can effectively increase the stiffness of the bearing, that is, the use of multiple layer wave foil structures can improve the overall stiffness of the bearing, increase the damping and heat dissipation efficiency of the bearing, improve the running stability of the bearing, and improve the bearing capacity of the bearing. BRIEF DESCRIPTION OF DRAWINGS

[0043] Figure 1 is the axial structure diagram of embodiment 1 of the radial gas dynamic pressure bearing of the application;

[0044] Figure 2 is a partial enlarged view of part A in Figure 1

[0045] Figure 3 is the axial structure diagram of embodiment 2 of the radial gas dynamic pressure bearing of the application;

[0046] Figure 4 is a partial enlarged view of part B in Figure 3

[0047] The reference signs are:

[0048] ​​1, top foil; 1-1, top foil fixed section; 1-2, top foil bearing section; 2, first layer wave foil; 2-1, first layer wave foil fixed section; 2-2, first layer wave foil flat section; 2-3, first layer wave foil support section; 2-31, first layer wave foil support section one; 2-32, first layer wave foil support section two; 2-33, first fixed end; 2-34, first free end; 2-35, second fixed end; 2-36, second free end; 2-37, first intermediate end; 2-38, second intermediate end; 3, second layer wave foil; 3-1, second layer wave foil fixed section; 3-2, second layer wave foil flat section; 3-3, second layer wave foil support section; 3-4, third fixed end; 3-5, fourth fixed end; 3-6, second layer wave peak end; 4, rotating shaft. DETAILED DESCRIPTION

[0049] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. The description of the at least one example embodiment is actually only illustrative, but not intended to limit the present application and its application or use in any way. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of the present application.

[0050] It should be noted that the terms used herein are only intended to describe specific embodiments, and are not intended to limit the example embodiments according to the present application. As used herein, the singular form is intended to include the plural form unless the context clearly indicates otherwise, and it should also be understood that when the terms "comprise" and / or "include" are used in the specification, there is a reference to the presence of a feature, step, operation, device, component, and / or combinations thereof.

[0051] Unless specifically stated otherwise, the relative arrangements of the components and steps illustrated in these embodiments and the numerical expressions and values set forth in the examples are not meant to limit the scope of the present application. At the same time, it should be understood that the sizes of the various parts shown in the drawings are not drawn in proportion. The techniques, methods and devices known to those skilled in the relevant art can not be discussed in detail, but should be considered as part of the authorized description. In all examples shown and discussed herein, any specific value should be interpreted as merely exemplary, and not as a limitation. Therefore, other examples of example embodiments can have different values. It should be noted that similar reference numbers and letters represent similar items in the following drawings, and therefore, once an item is defined in one drawing, it does not need to be further discussed in subsequent drawings.

[0052] In the description of the application, it needs to be understood that the orientation words such as "front, back, up, down, left, right", "transverse, vertical, perpendicular, horizontal" and "top, bottom" and the like indicated orientation or position relationship is generally based on the orientation or position relationship shown in the drawings, only for the convenience of describing the application and simplifying the description, without making the opposite statement, these orientation words do not indicate and imply that the device or element referred to must have a particular orientation or be constructed and operated in a particular orientation, therefore, it cannot be understood as a limitation on the scope of protection of the application; the orientation words "inner, outer" refer to the inner and outer relative to the contour of each component.

[0053] For the convenience of description, spatial relative terms such as "over", "above", "upper surface", "upper" and the like can be used herein to describe the spatial position relationship of one device or feature with other devices or features as shown in the drawings. It should be understood that the spatial relative terms are intended to include different orientations in use or operation in addition to the orientation of the device described in the drawings. For example, if the device in the drawing is inverted, the device described as "above" or "over" other devices or structures will be positioned "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below" orientations. The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein are interpreted accordingly.

[0054] In addition, it needs to be pointed out that the use of "first", "second" and the like to define parts only for the convenience of distinguishing the corresponding parts, and if there is no further statement, the above words have no special meaning, therefore, it cannot be understood as a limitation on the scope of protection of the application.

[0055] As shown in Figures 1-4 The present application provides a radial gas dynamic bearing, which comprises:

[0056] The top foil 1 and the first layer wave foil 2 arranged at the outer periphery of the top foil 1 to apply a supporting force to the top foil 1, the top foil 1 comprising a top foil bearing section 1-2, the first layer wave foil 2 comprising a first layer wave foil flat section 2-2, a first layer wave foil supporting section one 2-31 and a first layer wave foil supporting section two 2-32, the first layer wave foil flat section 2-2 being arranged at intervals between the top foil bearing section 1-2, the first layer wave foil supporting section one 2-31 and the first layer wave foil supporting section two 2-32 being both located between the first layer wave foil flat section 2-2 and the top foil bearing section 1-2, the radial outer ends of the first layer wave foil supporting section one 2-31 and the first layer wave foil supporting section two 2-32 being fixed, the radial inner ends of both being protruded towards the top foil bearing section 1-2 to be connected with the top foil bearing section 1-2 to support the top foil bearing section 1-2, and the radial inner end of the first layer wave foil supporting section one 2-31 and the radial inner end of the first layer wave foil supporting section two 2-32 being protruded towards each other and being spaced apart by a preset distance greater than 0.

[0057] The present application divides the first layer wave foil supporting section into the first layer wave foil supporting section one and the first layer wave foil supporting section two, and makes them spaced apart by a preset distance greater than 0 and protruded towards the top foil bearing section, so that both of the two spaced apart supporting sections can form support to the top foil bearing section, form a double wave peak structure, improve the line contact of the existing single wave peak support into the surface contact of the double wave peak support, reduce the support stiffness of the bearing at the wave peak, increase the deformation of the flat foil between the two wave peaks of the wave foil and the contact area of the flat foil and the wave foil, make the stiffness of the wave peak position uniform, reduce the wear, improve the overall life, effectively inhibit the high pressure gas end leakage due to the increase of the support area, and improve the service life and load carrying capacity of the bearing.

[0058] The present application provides a radial gas bearing, which increases the contact area of the wave foil and the top foil, reduces the support stiffness of the top of the wave foil, improves the anti-vibration performance, load carrying capacity and wear resistance of the bearing, solves the problems of easy wear and poor load carrying capacity of the existing foil gas dynamic pressure bearing, increases the load carrying capacity of the bearing under the premise of ensuring the dynamic adaptability of the bearing, and coordinates the deformation of the radial gas dynamic pressure bearing in the circumferential direction.

[0059] In the radial bearing operation, the first layer wave foil support section is elastically deformed under the pressure, the first layer wave foil support section one 2-31 and the first layer wave foil support section two 2-32 have large rigidity and small deformation, the area (gap) between the first layer wave foil support section one 2-31 and the first layer wave foil support section two 2-32 has small rigidity and large deformation, forming a groove, facilitating the storage of high-pressure gas, forming multiple high and low pressure areas in the circumferential direction of the radial bearing, increasing the compression effect of the gas and improving the load capacity of the bearing; because the wave foil changes from a single wave peak to a double wave peak structure, the contact area of the wave foil and the top foil is also increased by more than one time, increasing the bearing damping and improving the heat dissipation efficiency of the bearing.

[0060] In some embodiments,

[0061] The radial outer end of the first layer wave foil support section one 2-31 is a first fixed end 2-33, and the radial inner end is a first free end 2-34 extending towards the top foil bearing section 1-2, which can be connected with the top foil bearing section 1-2 when the top foil bearing section 1-2 bears a load, and can be connected or not connected with the top foil bearing section 1-2 when the top foil bearing section 1-2 does not bear a load.

[0062] The radial outer end of the first layer wave foil support section two 2-32 is a second fixed end 2-35, and the radial inner end is a second free end 2-36 extending towards the top foil bearing section 1-2, which can be connected with the top foil bearing section 1-2 when the top foil bearing section 1-2 bears a load, and can be connected or not connected with the top foil bearing section 1-2 when the top foil bearing section 1-2 does not bear a load.

[0063] This is the preferred structure of the first layer wave foil support section one and the first layer wave foil support section two of the present application, that is, the first free end and the second free end are formed to effectively contact the top foil bearing section for support. When supporting, the contact area of the first layer wave foil support section one and the top foil bearing section can be increased by deformation of the free end, and the contact area of the first layer wave foil support section two and the top foil bearing section can be increased by deformation of the second free end, so that the wave peak position is more uniform, the wear is reduced, and the overall life of the bearing is improved.

[0064] The present application provides a large-load radial foil gas bearing structure, as shown in Figure 1 and Figure 3 The radial bearing structure of the present application is composed of a top foil 1 (flat foil), a first layer wave foil 2, a second layer wave foil 3 and a rotating shaft 4. The first layer wave foil 2 and the second layer wave foil 3 are evenly distributed along the circumferential direction and have multiple circular arc support structures, which can be cold rolled into shape by using a precision mold, and the top foil 1 can be cut into shape.

[0065] The radial foil gas bearing structure of embodiment 1 is composed of one flat foil and one wave foil as shown in the prior art Figure 1 and Figure 2 The wave foil structure has: a first wave foil fixed section 2-1, a first wave foil flat section 2-2, a first wave foil support section one 2-31, and a first wave foil support section two 2-32. Compared with the prior art, the wave foil of the prior art adjusts the original single wave peak structure into left and right support sections, and the left and right support sections of the wave foil are flat wave peak structures, which are in contact with the flat foil bearing section, so that the stiffness distribution of the flat foil at the wave peak is more uniform, the wear of the flat foil at the wave peak of the wave foil is reduced, and the service life of the radial bearing is improved.

[0066] In some embodiments,

[0067] The first wave foil support section one 2-31 further includes a first intermediate end 2-37 between the first free end 2-34 and the first fixed end 2-33, and the part between the first intermediate end 2-37 and the first free end 2-34 is a first flat section in contact with the top foil bearing section 1-2. The first wave foil support section two 2-32 further includes a second intermediate end 2-38 between the second free end 2-36 and the second fixed end 2-35, and the part between the second intermediate end 2-38 and the second free end 2-36 is a second flat section in contact with the top foil bearing section 1-2.

[0068] This is a further preferred structure of the first wave foil support section one and the first wave foil support section two of the present application, that is, having a first intermediate end between the first free end and the first fixed end, so that when subjected to the extrusion of the top foil bearing section, the first flat section is formed between the first intermediate end and the first free end to effectively support the top foil bearing section, increase the contact area (from the line contact of the original single wave peak structure to the surface contact), thereby increasing the support area of the top foil bearing section, and the position of the first intermediate end can change with the size of the force applied by the top foil bearing section (due to the change in the stress deformation of the free end of the first wave foil support section one); having a second intermediate end between the second free end and the second fixed end, so that when subjected to the extrusion of the top foil bearing section, the second flat section is formed between the second intermediate end and the second free end to effectively support the top foil bearing section, increase the contact area (from the line contact of the original single wave peak structure to the surface contact), thereby increasing the support area of the top foil bearing section, and the position of the second intermediate end can change with the size of the force applied by the top foil bearing section (due to the change in the stress deformation of the free end of the first wave foil support section two).

[0069] In some embodiments,

[0070] The part between the first fixed end 2-33 and the first intermediate end 2-37 in the projection plane of the axial end face is an arc segment structure, the first flat segment is a straight segment that is attached to the top foil bearing segment 1-2, the part between the second fixed end 2-35 and the second intermediate end 2-38 is an arc segment structure, and the second flat segment is a straight segment that is attached to the top foil bearing segment 1-2.

[0071] This is a further preferred structure of the first layer wave foil support segment one and the first layer wave foil support segment two of the present application, that is, the first flat segment is a straight segment that is attached to the top foil bearing segment, which can increase the contact area between the top foil bearing segment and the first layer wave foil support segment, increase the support area, the part between the first fixed end and the first intermediate end is an arc segment structure, which is conducive to transmitting deformation and improving support effect; the second flat segment is a straight segment that is attached to the top foil bearing segment, which can increase the contact area between the top foil bearing segment and the second layer wave foil support segment, increase the support area, and the part between the second fixed end and the second intermediate end is an arc segment structure, which is conducive to transmitting deformation and improving support effect.

[0072] In some embodiments,

[0073] In the circumferential direction, the distance between the first free end 2-34 and the second free end 2-36 is less than the distance between the first fixed end 2-33 and the second fixed end 2-35.

[0074] The first layer wave foil flat segment 2-2 is an arc segment structure or a ring segment structure that is arranged around the outer periphery of the top foil bearing segment 1-2.

[0075] The present application can convert the force into deformation and decompose it in multiple directions when the first and second free ends are subjected to the load of the top foil bearing segment, and then transmit it to the first and second fixed ends, thereby forming a stable and effective support for the first and second free ends, by setting the circumferential distance between the first and second free ends to be less than the circumferential distance between the first and second fixed ends; the first layer wave foil flat segment is preferably an arc segment structure or a ring segment structure to provide effective support from the radial outside to the radial inside for the first layer wave foil support segment one and two.

[0076] Embodiment 1, as Figures 1-2 In some embodiments,

[0077] The first fixed end 2-33 is fixedly connected to the inner peripheral wall of the first layer wave foil flat segment 2-2, and the second fixed end 2-35 is fixedly connected to the inner peripheral wall of the first layer wave foil flat segment 2-2.

[0078] The first layer wave foil support section one 2-31 and the first layer wave foil support section two 2-32 form a first support unit, and a plurality of first support units are arranged on the inner circumferential wall of the first layer wave foil flat section 2-2 in the circumferential direction, that is, each two adjacent first support units are arranged at intervals.

[0079] This is the preferred structure of embodiment 1 of the application, that is, a one-layer wave foil structure, the first layer wave foil support section one and two are fixedly connected to the inner circumferential wall of the first layer wave foil flat section, forming a stable support for the first layer wave foil support section one and two; by forming a first support unit through the first layer wave foil support section one and two, and arranging a plurality of first support units at intervals in the circumferential direction, the top foil bearing section can be effectively supported in multiple places in the circumferential direction, thereby improving the support effect of the top foil bearing section.

[0080] Embodiment 2, as Figures 3-4 In some embodiments,

[0081] Further comprising a second layer wave foil 3, the second layer wave foil 3 comprises a second layer wave foil flat section 3-2 and a second layer wave foil support section 3-3, the second layer wave foil flat section 3-2 is arranged on the outer circumferential wall of the first layer wave foil flat section 2-2, the first layer wave foil support section one 2-31 and the first layer wave foil support section two 2-32 are arranged on the inner circumferential wall of the first layer wave foil flat section 2-2 and protrude towards the top foil bearing section 1-2, the second layer wave foil support section 3-3 is arranged on the inner circumferential wall of the second layer wave foil flat section 3-2 and protrudes towards the top foil bearing section 1-2, the first layer wave foil support section one 2-31 is located between the second layer wave foil support section 3-3 and the top foil bearing section 1-2, and the first layer wave foil support section two 2-32 is located between the second layer wave foil support section 3-3 and the top foil bearing section 1-2.

[0082] The application further comprises a second layer wave foil arranged on the outer circumferential wall of the first layer wave foil, and a second layer wave foil support section with an arch height smaller than the first layer wave foil support section one and two, which effectively forms a double-layer wave foil support structure for the top foil bearing section, and the use of double-layer wave foil can effectively increase the stiffness of the bearing, that is, the use of multiple-layer wave foil structure can improve the overall stiffness of the bearing, increase the damping and heat dissipation efficiency of the bearing, improve the running stability of the bearing, and improve the load bearing performance of the bearing.

[0083] In some embodiments,

[0084] The second layer wave foil support section 3-3 is connected to the second layer wave foil flat section 3-2 at a third fixed end 3-4, which is fixedly connected to the second layer wave foil flat section 2-2, and at a fourth fixed end 3-5, which is fixedly connected to the second layer wave foil flat section 2-2. The structure between the third fixed end 3-4 and the fourth fixed end 3-5 is a continuous structure that protrudes in the direction of the top foil bearing section 1-2.

[0085] This is the preferred structure of the second layer wave foil of the present application, that is, the protruding continuous structure between the third fixed end and the fourth fixed end can effectively contact the top foil bearing section for support. As the load on the top foil bearing section gradually increases, the first and second free ends first support the top foil bearing section, and as the first and second free ends further deform, the top foil bearing section contacts the second layer wave foil support section, which further provides support to the top foil bearing section through deformation of the second layer wave foil support section, thereby improving the overall stiffness of the bearing and improving the load carrying capacity of the bearing.

[0086] In some embodiments,

[0087] In the projection plane of the axial end surface, the second layer wave foil support section 3-3 is an arc-shaped section structure. Along the radial direction, the radial distance between the first free end 2-34 and the first fixed end 2-33 is the arch height H1 of the first layer wave foil support section one 2-31, the radial distance between the second free end 2-36 and the second fixed end 2-35 is the arch height H2 of the first layer wave foil support section two 2-32, and the position of the second layer wave peak end 3-6 closest to the top foil bearing section 1-2 is the second layer wave peak end 3-6. Along the radial direction, the radial distance between the second layer wave peak end 3-6 and the third fixed end 3-4, and the radial distance between the second layer wave peak end 3-6 and the fourth fixed end 3-5 are equal, both being the arch height H3 of the second layer wave foil support section 3-3, and H1 > H3, H2 > H3.

[0088] The second layer wave foil support section of the present application is preferably a continuous arc section structure which can provide a second effective support for the top foil bearing section, and the arch height H3 of the second layer wave foil support section is set to be less than the arch height H1 of the first layer wave foil support section one and less than the arch height H2 of the first layer wave foil support section two, so that when the support stress of the top foil bearing section at the first free end and the second free end is deformed to a certain extent, the top foil bearing section is supported by the second layer wave peak end or the first layer wave foil support section one and two are in contact with the second layer wave peak end to support the top foil bearing section, forming a light load support and a heavy load support for the top foil bearing section according to the size of the load, and further improving the support capacity of the bearing.

[0089] In some embodiments,

[0090] H3 = 0.7H1 = 0.7H2; or, the first layer wave foil support section two is the air entraining side, and the first layer wave foil support section one is the exhaust side, then H1 > H2.

[0091] This is the relationship between the arch height of the second layer wave foil support section and the arch height of the first layer wave foil support section one and two of the present application.

[0092] The radial foil gas bearing structure of the embodiment 2 of the present application is composed of a top foil 1, a first layer wave foil 2 and a second layer wave foil 3 as shown in the drawings. Figure 3 and Figure 4 The first layer wave foil support section one 2-31 and the first layer wave foil support section two 2-32 are in contact with the top foil bearing section 1-2; the second layer wave foil flat section 3-2 is in contact with the first layer wave foil flat section 2-2, and the second layer wave foil support section 3-3 is slightly lower than the arch height of the first layer wave foil support section one and two, that is, the height difference value should be less than 30% of the arch height value of the first layer wave foil support section one or two. When the radial bearing is working, the first layer wave foil left and right support sections are in contact with the top foil under light load, and at this time the bearing stiffness is the support stiffness of the first layer wave foil. Under heavy load, the first layer wave foil support section one 2-31 and the first layer wave foil support section two 2-32 are in contact with the second layer wave foil support section 3-3, and at this time the bearing stiffness is the sum of the support stiffness of the first layer wave foil and the second layer wave foil. When the height values of the two layer wave foil support sections are greatly different, the first layer wave foil deforms greatly under heavy load when the radial bearing is working, at this time the second layer wave foil is not in contact with the first layer wave foil support section, the gap between the bearing and the rotating shaft suddenly increases, which will cause the rotating shaft to lose stability, and even the motor to fail abnormally. The present application sets the second layer arch height to about 70% of the first layer arch height, which can effectively avoid the above situation, so that the first layer wave foil is deformed and supported without affecting the stability of the rotating shaft, and the second layer wave foil effectively supports it, thereby improving the stability of the bearing support.

[0093] On one hand, the peak structures and sizes of the left and right support segments are the same, and the left and right support segments jointly provide support stiffness for the bearing under the action of pressure, and the bearing has good reliability; on the other hand, the peak structures of the left and right support segments are the same, and the peak height values are different, and under the action of pressure during bearing operation, one side of the support segment is in contact with the top foil and is elastically deformed, and then the other side is also in contact with the top foil and is deformed, the left and right support segments form high and low peaks, the bearing stiffness presents a gradual gradient, and the peak height of the air introduction side is slightly lower and the peak height of the air exhaust side is slightly higher, which can help to introduce more gas into the space between the two peaks to support the top foil bearing segment by gas, and reduce the gas end leakage on the high pressure side of the air exhaust.

[0094] In some embodiments,

[0095] In the circumferential direction, the second layer wave foil support segment 3-3 is located between the first fixed end 2-33 and the second fixed end 2-35; in the radial direction, the first free end 2-34 is located between the second layer wave foil support segment 3-3 and the top foil bearing segment 1-2, and the second free end 2-36 is located between the second layer wave foil support segment 3-3 and the top foil bearing segment 1-2.

[0096] This is the preferred setting position of the second layer wave foil support segment of the application, in the circumferential direction, the second layer wave foil support segment is located between the first fixed end and the second fixed end of the first layer wave foil support segment, and in the radial direction, the first layer wave foil support segment one and the first layer wave foil support segment two are both located between the top foil bearing segment and the second layer wave foil support segment, that is, the first layer wave foil support segment one and two first form a first support for the top foil bearing segment, and then the second layer wave foil support segment forms a second support for the top foil bearing segment, thereby improving the support performance of the bearing.

[0097] In some embodiments,

[0098] The first layer wave foil support segment one 2-31, the first layer wave foil support segment two 2-32 and the second layer wave foil support segment 3-3 form a second support unit, and a plurality of second support units are arranged in the circumferential direction.

[0099] The application forms a second support unit by the first layer wave foil support segment one and two and the second layer wave foil support segment, and a plurality of second support units are arranged in the circumferential direction, which can effectively support the top foil bearing segment in multiple places in the circumferential direction, thereby further improving the support effect of the top foil bearing segment.

[0100] In some embodiments,

[0101] Further comprising a top foil fixing section 1-1 and a first layer wave foil fixing section 2-1, one end of the top foil fixing section 1-1 is connected with the top foil bearing section 1-2, the other end extends to the radial outside, one end of the first layer wave foil fixing section 2-1 is connected with the first layer wave foil flat section 2-2, the other end extends to the radial outside, the part of the top foil fixing section 1-1 extending to the radial outside is fixed with the part of the first layer wave foil fixing section 2-1 extending to the radial outside.

[0102] The top foil fixing section and the first layer and second layer wave foil supporting sections are fixed in the same position, so that the top foil and the first layer and second layer wave foils are effectively fixed as a whole, the supporting effect of the first layer and second layer wave foils on the top foil bearing section is ensured, and the supporting effect on the rotating shaft 4 is further ensured and improved.

[0103] In some embodiments,

[0104] Further comprising a second layer wave foil fixing section 3-1, the second layer wave foil fixing section 3-1 is arranged at the same position as the first layer wave foil fixing section 2-1, one end of the second layer wave foil fixing section 3-1 is connected with the second layer wave foil flat section 3-2, the other end extends to the radial outside, the part of the second layer wave foil fixing section 3-1 extending to the radial outside is fixed with the part of the first layer wave foil fixing section 2-1 extending to the radial outside.

[0105] The top foil fixing section and the first layer and second layer wave foil supporting sections are fixed in the same position, so that the top foil and the first layer and second layer wave foils are effectively fixed as a whole, the supporting effect of the first layer and second layer wave foils on the top foil bearing section is ensured, and the supporting effect on the rotating shaft 4 is further ensured and improved.

[0106] The application further provides an electric machine comprising the radial gas dynamic bearing.

[0107] The improvement of the application lies in that:

[0108] 1. The wave foil sheet adopts a double-wave peak structure, which reduces the supporting stiffness of the bearing at the wave peaks, increases the deformation of the flat foil between the two wave peaks of the wave foil and the contact area of the flat foil and the wave foil, suppresses the end leakage of high-pressure gas, and improves the service life and load-carrying capacity of the bearing.

[0109] 2. The use of a multi-layer wave foil structure improves the overall stiffness of the bearing, increases the damping and heat dissipation efficiency of the bearing, and improves the running stability of the bearing.

[0110] The above merely describes preferred embodiments of the present application and is not used to limit the present application, and any modification, equivalent replacement and improvement made within the spirit and principle of the present application shall be included in the protection scope of the present application. The above merely describes preferred embodiments of the present application and is not used to limit the present application, and any modification, equivalent replacement and improvement made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A radial gas dynamic pressure bearing, characterized by: Comprise: A top foil (1) and a first layer wave foil (2) arranged at the outer periphery of the top foil (1) to apply a supporting force to the top foil (1), the top foil (1) comprising a top foil bearing section (1-2), the first layer wave foil (2) comprising a first layer wave foil flat section (2-2), a first layer wave foil supporting section one (2-31) and a first layer wave foil supporting section two (2-32), the first layer wave foil flat section (2-2) being arranged at an interval between the top foil bearing section (1-2), the first layer wave foil supporting section one (2-31) and the first layer wave foil supporting section two (2-32) being both located between the first layer wave foil flat section (2-2) and the top foil bearing section (1-2), the radial outer ends of the first layer wave foil supporting section one (2-31) and the first layer wave foil supporting section two (2-32) are both fixed, the radial inner ends of the first layer wave foil supporting section one (2-31) and the first layer wave foil supporting section two (2-32) both protrude towards the top foil bearing section (1-2) to interface with the top foil bearing section (1-2) to support the top foil bearing section (1-2), and the radial inner ends of the first layer wave foil supporting section one (2-31) and the first layer wave foil supporting section two (2-32) protrude towards each other by a preset distance greater than 0.

2. The radial gas dynamic bearing according to claim 1, wherein: the radial outer end of the first layer wave foil supporting section one (2-31) is a first fixed end (2-33), and the radial inner end is a first free end (2-34) protruding towards the top foil bearing section (1-2), the first free end (2-34) can interface with the top foil bearing section (1-2) when the top foil bearing section (1-2) is under load, and the first free end (2-34) can interface with or not interface with the top foil bearing section (1-2) when the top foil bearing section (1-2) is not under load; the radial outer end of the first layer wave foil supporting section two (2-32) is a second fixed end (2-35), and the radial inner end is a second free end (2-36) protruding towards the top foil bearing section (1-2), the second free end (2-36) can interface with the top foil bearing section (1-2) when the top foil bearing section (1-2) is under load, and the second free end (2-36) can interface with or not interface with the top foil bearing section (1-2) when the top foil bearing section (1-2) is not under load.

3. The radial gas dynamic bearing according to claim 2, wherein: The first layer wave foil support section one (2-31) further comprises a first intermediate end (2-37) between the first free end (2-34) and the first fixed end (2-33), and the part between the first intermediate end (2-37) and the first free end (2-34) is a first flat section connected with the top foil bearing section (1-2); the first layer wave foil support section two (2-32) further comprises a second intermediate end (2-38) between the second free end (2-36) and the second fixed end (2-35), and the part between the second intermediate end (2-38) and the second free end (2-36) is a second flat section connected with the top foil bearing section (1-2).

4. The radial aerodynamic bearing according to claim 3, wherein: In the projection plane of the axial end surface, the part between the first fixed end (2-33) and the first intermediate end (2-37) is an arc section structure, the first flat section is a straight section abutting the top foil bearing section (1-2), the part between the second fixed end (2-35) and the second intermediate end (2-38) is an arc section structure, and the second flat section is a straight section abutting the top foil bearing section (1-2).

5. The radial aerodynamic bearing according to claim 2, wherein: In the circumferential direction, the distance between the first free end (2-34) and the second free end (2-36) is less than the distance between the first fixed end (2-33) and the second fixed end (2-35); The first layer wave foil flat section (2-2) is an arc section structure or a ring section structure arranged around the outer periphery of the top foil bearing section (1-2).

6. The radial aerodynamic bearing according to claim 2, wherein: The first fixed end (2-33) is fixedly connected to the inner peripheral wall of the first layer wave foil flat section (2-2), and the second fixed end (2-35) is fixedly connected to the inner peripheral wall of the first layer wave foil flat section (2-2); The first layer wave foil support section one (2-31) and the first layer wave foil support section two (2-32) form a first support unit, and a plurality of first support units are arranged on the inner peripheral wall of the first layer wave foil flat section (2-2) in the circumferential direction, i.e., every two adjacent first support units are arranged at intervals.

7. The radial aerodynamic bearing according to any one of claims 2-6, wherein: Further comprising a second layer wave foil (3), the second layer wave foil (3) comprises a second layer wave foil flat section (3-2) and a second layer wave foil support section (3-3), the second layer wave foil flat section (3-2) is arranged on the outer circumferential wall of the first layer wave foil flat section (2-2), the first layer wave foil support section one (2-31) and the first layer wave foil support section two (2-32) are respectively arranged on the inner circumferential wall of the first layer wave foil flat section (2-2) and protrude towards the top foil bearing section (1-2), the second layer wave foil support section (3-3) is arranged on the inner circumferential wall of the second layer wave foil flat section (3-2) and protrudes towards the top foil bearing section (1-2), the first layer wave foil support section one (2-31) is located between the second layer wave foil support section (3-3) and the top foil bearing section (1-2), and the first layer wave foil support section two (2-32) is located between the second layer wave foil support section (3-3) and the top foil bearing section (1-2).

8. The radial aerodynamic gas bearing according to claim 7, wherein: The end of the second layer wave foil support section (3-3) connected with the second layer wave foil flat section (3-2) is a third fixed end (3-4), the third fixed end (3-4) is fixedly connected with the second layer wave foil flat section (3-2), the other end of the second layer wave foil support section (3-3) connected with the second layer wave foil flat section (3-2) is a fourth fixed end (3-5), the fourth fixed end (3-5) is fixedly connected with the second layer wave foil flat section (3-2), and the structure between the third fixed end (3-4) and the fourth fixed end (3-5) is a continuous structure protruding towards the top foil bearing section (1-2).

9. The radial aerodynamic gas bearing according to claim 8, wherein: In the projection plane of the axial end surface, the second layer wave foil support section (3-3) is an arc-shaped section structure; along the radial direction, the radial distance between the first free end (2-34) and the first fixed end (2-33) is the arch height H1 of the first layer wave foil support section one (2-31), the radial distance between the second free end (2-36) and the second fixed end (2-35) is the arch height H2 of the first layer wave foil support section two (2-32), the position closest to the top foil bearing section (1-2) of the second layer wave foil support section (3-3) is a second layer wave peak end (3-6), along the radial direction, the radial distance between the second layer wave peak end (3-6) and the third fixed end (3-4) and the radial distance between the second layer wave peak end (3-6) and the fourth fixed end (3-5) are equal, both being the arch height H3 of the second layer wave foil support section (3-3), and H1>H3, H2>H3.

10. The radial aerodynamic gas bearing according to claim 9, wherein: H3=0.7H1=0.7H2; or, the first layer wave foil support section two is the air supply side, and the first layer wave foil support section one is the air exhaust side, then H1>H2.

11. The radial aerodynamic gas bearing of claim 7, wherein: the second layer wave foil support section (3-3) is located between the first fixed end (2-33) and the second fixed end (2-35) in the circumferential direction; the first free end (2-34) is located between the second layer wave foil support section (3-3) and the top foil bearing section (1-2) in the radial direction; and the second free end (2-36) is located between the second layer wave foil support section (3-3) and the top foil bearing section (1-2) in the radial direction.

12. The radial aerodynamic gas bearing of claim 7, wherein: the first layer wave foil support section one (2-31), the first layer wave foil support section two (2-32), and the second layer wave foil support section (3-3) form a second support unit, and a plurality of the second support units are arranged in the circumferential direction.

13. The radial aerodynamic gas bearing of claim 7, further comprising a top foil fixed section (1-1) and a first layer wave foil fixed section (2-1), wherein one end of the top foil fixed section (1-1) is connected to the top foil bearing section (1-2), and the other end of the top foil fixed section (1-1) extends outward in the radial direction; one end of the first layer wave foil fixed section (2-1) is connected to the first layer wave foil flat section (2-2), and the other end of the first layer wave foil fixed section (2-1) extends outward in the radial direction; and the portion of the top foil fixed section (1-1) extending outward in the radial direction is fixed to the portion of the first layer wave foil fixed section (2-1) extending outward in the radial direction.

14. The radial aerodynamic gas bearing of claim 13, further comprising a second layer wave foil fixed section (3-1), wherein the second layer wave foil fixed section (3-1) is arranged at the same position as the first layer wave foil fixed section (2-1); one end of the second layer wave foil fixed section (3-1) is connected to the second layer wave foil flat section (3-2), and the other end of the second layer wave foil fixed section (3-1) extends outward in the radial direction; and the portion of the second layer wave foil fixed section (3-1) extending outward in the radial direction is fixed to the portion of the first layer wave foil fixed section (2-1) extending outward in the radial direction. The radial aerodynamic gas bearing of any one of claims 1-14. ​ 15. An electric machine characterized by: ​

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