A radial dynamic pressure air bearing

Abstract

The present application relates to a radial dynamic pressure air bearing, which includes a bearing sleeve and at least one support assembly, the support assembly includes a retaining frame arranged in the bearing sleeve and at least one elastic support arm, a distance is left between the retaining frame and the bearing sleeve, the support arm is arranged between the bearing sleeve and the retaining frame, the support arm is provided with at least two abutting parts for abutting against the inner wall of the bearing sleeve, each abutting part is distributed in a circle around the retaining frame, and a gap is left between the abutting part and the retaining frame so that the abutting part can be deformed. When the dynamic pressure air film is just beginning to form, the support arm is more likely to deform, and when the dynamic pressure air film is gradually formed, the support arm is gradually more difficult to deform, so that the deformation degree of the support arm and the formation degree of the dynamic pressure air film reach a dynamic balance, so that the dynamic pressure air film supports the inner rotor more evenly and stably, and achieves a smaller take-off speed.

Description

Technical Field

[0001] The present application relates to the field of bearings, and in particular to a radial dynamic pressure air bearing. Background Art

[0002] Radial dynamic pressure air bearing, also known as air dynamic pressure bearing, air floating bearing, is a kind of bearing that uses gas as lubricant. Compared with traditional ball bearings, radial dynamic pressure air bearings have the characteristics of no need for lubrication, high operating speed, small mechanical loss and low maintenance cost. Generally, radial dynamic pressure air bearings include at least a top foil, a support assembly and a bearing sleeve arranged in sequence from the inside to the outside, wherein the support assembly can support the top foil in the bearing sleeve, and the operator can set the inner rotor in the top foil. In the working state, the inner rotor rotates in the top foil, and a dynamic pressure air film formed by gas with kinetic energy can be formed between the outer peripheral wall of the inner rotor and the inner surface of the top foil. The dynamic pressure air film exerts a radial force on the inner rotor to support the inner rotor.

[0003] In the related art, for example, a Chinese invention patent application with application publication number CN108180223 supporting assembly discloses a radial foil dynamic pressure air bearing with a thick top foil structure, which includes a bearing seat, a supporting foil and a top foil, wherein the top foil is sleeved in the bearing seat, and the supporting foil is assembled between the bearing seat and the top foil. The inner ring surface of the supporting foil contacts the top foil, and the outer ring surface of the supporting foil contacts the bearing seat.

[0004] With regard to the above-mentioned related technologies, the inventors believe that the related technologies use a supporting corrugated foil as a supporting component, and the supporting corrugated foil is composed of a plurality of continuously distributed arch structures. When any arch structure is deformed, the deformed arch structure is easily affected by other arch structures at a closer distance, resulting in that the deformation amount of the supporting corrugated foil is difficult to control. Not only does it make it difficult for the supporting corrugated foil to provide sufficient and stable space for the dynamic pressure air film through deformation within a short period of time after the start of operation, resulting in that the dynamic pressure air film is difficult to form continuously and quickly, making the take-off speed of the radial foil dynamic pressure air bearing relatively high, but it also reduces the supporting corrugated foil's ability to absorb the impact load of the inner rotor, resulting in that the radial foil dynamic pressure air bearing is not stable enough during operation. Summary of the invention

[0005] In order to improve the working stability of a radial dynamic pressure air bearing, the present application provides a radial dynamic pressure air bearing.

[0006] The present application provides a radial dynamic pressure air bearing, which adopts the following technical solution:

[0007] A radial dynamic pressure air bearing comprises a bearing sleeve and at least one supporting assembly, wherein the supporting assembly comprises a retaining frame arranged in the bearing sleeve and at least one elastic supporting arm, wherein a distance is left between the retaining frame and the bearing sleeve, the supporting arm is arranged between the bearing sleeve and the retaining frame, and the supporting arm is provided with at least two abutting portions for abutting against the inner wall of the bearing sleeve, wherein each of the abutting portions is distributed in a circle around the retaining frame, and a gap is left between the abutting portion and the retaining frame so that the abutting portion can be deformed.

[0008] By adopting the above technical solution, the retainer can fix each support arm in the bearing sleeve, and each support arm contacts the bearing sleeve through the contact part, so that there is space between the retainer and the bearing sleeve. When the radial dynamic pressure air bearing is in working state, under the influence of the dynamic pressure air film formed inside the radial dynamic pressure air bearing, the retainer will gradually move toward the inner side of the bearing sleeve, so that the support arm will gradually deform, and the space between the contact part and the retainer will gradually become smaller. Since the inner wall of the bearing sleeve is arc-shaped, the support arm will gradually bend when deformed. In this process, the distance between the contact parts at both ends of the support arm will gradually decrease, so that the deformable range of the support arm will gradually decrease. It is equivalent to that when the dynamic pressure air film just begins to form, the support arm is easier to absorb the stamping load and deform, and when the dynamic pressure air film is gradually formed, the support arm is gradually more difficult to deform, thereby increasing the support stiffness, so that the support stiffness change of the support arm and the gradual formation degree of the dynamic pressure air film reach a dynamic balance.

[0009] When the dynamic pressure air film begins to form, since the support arm is easy to deform, the radial dynamic pressure air bearing can quickly reserve space for the dynamic pressure air film to form, reducing the limitation of space on the formation of the dynamic pressure air film so that the dynamic pressure air film can be formed continuously and stably, achieving a lower takeoff speed. At the same time, since the support arm has a good impact load absorption capacity when the dynamic pressure air film begins to form, the impact of the inner rotor on the radial foil dynamic pressure air bearing is reduced, and the working stability of the radial foil dynamic pressure air bearing is improved.

[0010] On the other hand, since the support stiffness of the support arm increases with the increase in deformation, when the dynamic pressure air film has been formed, the support arm can still provide a large support stiffness so that the radial dynamic pressure air bearing can maintain good working stability.

[0011] Optionally, the support assembly further includes at least two keels distributed circumferentially around the retaining frame, and each support arm is arranged on the keel at intervals, and the retaining frame is provided with at least two clamping plates arranged on both sides of the keel and capable of contacting the keel, and a distance is left between the clamping plate and the retaining frame to form a clamping space for accommodating the keel.

[0012] By adopting the above technical solution, the keel is arranged in the clamping space, and the retaining frame cooperates with the clamping sheet to clamp the keel, so that the keel and the retaining frame are relatively fixed, and then each support arm and the retaining frame are relatively fixed.

[0013] Optionally, the keel is arranged along the axial direction of the bearing sleeve, and the minimum distances between each of the abutting portions and the axis of the bearing sleeve are equal; and each of the fixing portions located on the same keel is symmetrically arranged on both sides of the keel.

[0014] By adopting the above technical solution, since the minimum distance between each abutment and the axis of the bearing sleeve is equal, the support arm is tangent to the inner side of the bearing sleeve. When the length direction of the keel is parallel to the axial direction of the bearing sleeve, each abutment on both sides of the keel can abut the inner wall of the bearing sleeve. At the same time, the clamping pieces symmetrically arranged on both sides of the keel can make the forces on both sides of the keel uniform, reducing the risk of the keel shifting. On the other hand, when the keel is tilted, the support arm also deviates from the position, and the forces between each abutment on the keel and the inner wall of the bearing sleeve are uneven, among which the forces between some abutment and the bearing sleeve are large, and some abutment and the bearing sleeve are not in contact, resulting in uneven forces on both ends of the support arm; and when the radial dynamic pressure air bearing is in working state, the pressure of the dynamic pressure air film will press each support arm, so that the support arm gradually returns to the state of uniform forces on both ends, that is, the support arm returns to the normal position, and at the same time, the keel is parallel to the axial direction of the bearing sleeve again, completing automatic centering. On the other hand, before the pressure of the dynamic pressure air film overcomes the mass of the inner rotor, the top foil abuts against the outer peripheral wall of the inner rotor, and each support arm supports the top foil to support the inner rotor in the bearing sleeve. At this time, since the minimum distances between each abutting portion and the axis of the bearing sleeve are equal, the inner rotor can be kept coaxial with the bearing sleeve, thereby improving the coaxiality between the inner rotor and the bearing sleeve before the dynamic pressure air film is formed, making it easier for the bearing sleeve to maintain a state close to coaxial with the inner rotor when in working condition.

[0015] Optionally, the retaining frame is provided with a slit portion for forming the clamping plate and dividing the retaining frame, the slit portion includes a first slit corresponding to the end of the clamping plate and a second slit corresponding to both sides of the clamping plate, and an angle is formed between the first slit and the second slit; the retaining frame can be bent to separate the clamping plate from the slit portion.

[0016] By adopting the above technical solution, when processing each clamping piece, the manufacturer can cut a slit portion on the retaining frame and then bend the retaining frame. When the retaining frame is bent, the two sides of the clamping piece are separated from the retaining frame through the second slit respectively, one end of the clamping piece is connected to the retaining frame, and the other end of the clamping piece is separated from the retaining frame through the first slit, so that the clamping piece is formed.

[0017] Optionally, the radial dynamic pressure air bearing further comprises a top foil, wherein the top foil is arranged on a side of the retaining frame away from the support arms, and the support arms on two adjacent keels are staggeredly distributed.

[0018] By adopting the above technical solution, the connection between the support arm and the keel corresponds to the main stress point of the top foil, and the support arms located on different keels are staggered, which is equivalent to making the distribution of the main stress points between the support arm and the top foil more even, so that each support arm can achieve a better support effect.

[0019] Optionally, the space between two adjacent support arms on the same keel forms a separation space, and the two ends of the retaining frame form an upstream end and a downstream end along the rotation direction of the radial dynamic pressure air bearing, and the minimum width of the separation space gradually increases from the downstream end to the upstream end.

[0020] By adopting the above technical solution, when the radial dynamic pressure air bearing just starts to work, the pressure of the dynamic pressure air film is relatively small. As the radial dynamic pressure air bearing continues to work, the pressure of the dynamic pressure air film will become larger and larger. The smaller the width of the separation space, the greater the support force of the support arm on the top foil, that is, the smaller the deformation range of the support arm. Therefore, the minimum width of the separation space is gradually increased from the downstream end to the upstream end, which is equivalent to making the support arm close to the initial generation position of the dynamic pressure air film easier to deform, making the deformation difficulty of the support arm gradually increase with the increase of the pressure of the dynamic pressure air film, making the dynamic pressure air film easier to form and more stable.

[0021] Optionally, the bearing sleeve includes at least two outer sleeve rings distributed radially and coaxially arranged.

[0022] By adopting the above technical solution, the bearing sleeve is composed of a plurality of coaxially arranged outer rings. Compared with the integrally formed bearing sleeve, the outer rings are easier to process and produce, thereby reducing the production cost.

[0023] Optionally, at least one retaining weir is provided in the bearing sleeve, and the number of the retaining frames corresponds to the number of the retaining weirs, and an installation position for installing one of the retaining frames is formed between the two sides of one of the retaining weirs and the inner side of the bearing sleeve and / or between the two closest retaining weirs and the inner side of the bearing sleeve; both ends of the retaining frame can contact the retaining weir closest to it.

[0024] By adopting the above technical solution, the retaining weir has a limiting effect on the retaining frame located in the installation position corresponding to it, preventing the retaining frame and the bearing sleeve from rotating relative to each other.

[0025] Optionally, an air guide portion corresponding to the weir is provided in the bearing sleeve, and the air guide portion includes at least two air guide grooves distributed at intervals, and a weir is formed between the two closest air guide grooves; the radial dynamic pressure air bearing also includes a top foil arranged in the mounting position, and the two ends of the top foil are respectively accommodated in the two closest air guide grooves.

[0026] By adopting the above technical solution, in the working state, since the two ends of the top foil are respectively accommodated in the air guide groove, a gap is left between the two ends of the top foil and the outer peripheral wall of the inner rotor, and the air in the atmosphere can enter between the top foil and the inner rotor through the gap, thereby accelerating the formation rate of the dynamic pressure control film. One side of the retaining weir matches the inner side of the bearing sleeve, reducing the friction between the retaining weir and the inner rotor, and reducing the shielding of the air in the axial direction of the bearing sleeve.

[0027] Optionally, an air guiding wedge surface is provided at the bottom of the air guiding groove, and the air guiding wedge surface is tangent to the inner side of the bearing sleeve.

[0028] By adopting the above technical solution, the air guide wedge surface can make it easier for air in the atmosphere to enter between the top foil and the inner rotor, and reduce the interference with the air to reduce the generation of air vortices, making it easier to generate a dynamic pressure air film. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a schematic diagram of the working state of the radial dynamic pressure air bearing according to an embodiment of the present application.

[0030] Figure 2 It is a front view of the radial dynamic pressure air bearing according to an embodiment of the present application.

[0031] Figure 3 It is a schematic diagram of the structure of the outer sleeve ring of an embodiment of the present application.

[0032] Figure 4 yes Figure 1 Exploded view of the top foil, support assembly, and bearing housing.

[0033] Figure 5 yes Figure 4 Exploded view of the top foil, retainer and support spring.

[0034] Figure 6 It is a schematic diagram of the state of the supporting spring from before the dynamic pressure air film is formed to after the dynamic pressure air film is formed.

[0035] Figure 7 It is a schematic diagram of the state of a radial dynamic pressure air bearing from before the formation of the dynamic pressure air film to after the formation of the dynamic pressure air film.

[0036] Figure 8 2 is a diagram of the unfolded state of the retaining frame according to an embodiment of the present application.

[0037] Fig. 9 yes Figure 5 A local enlarged schematic diagram of point A in the middle.

[0038] Description of reference numerals:

[0039] 1. Bearing sleeve; 12. Baffle; 13. Mounting position; 14. Initial air guide port; 2. Outer ring; 21. Baffle; 22. Air guide groove; 221. Concave surface; 3. Support assembly; 4. Support spring; 41. Keel; 42. Support arm; 421. Interference part; 422. Support part; 423. Partition space; 5. Retaining frame; 51. Clamping sheet; 52. Slit part; 521. First slit; 522. Second slit; 53. Upstream end; 54. Downstream end; 55. Midstream part; 6. Top foil; 61. Air guide wedge surface; 62. Connection area; 7. Inner rotor; 8. Bearing cover. DETAILED DESCRIPTION

[0040] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0041] In addition, the term "and / or" in this article is only a description of the association relationship of the associated objects, indicating that there can be three relationships. For example, support component 3 and / or B can represent: the existence of support component 3 alone, the existence of support component 3 and B at the same time, and the existence of B alone. In addition, the character " / " in this article, unless otherwise specified, generally indicates that the associated objects before and after are in an "or" relationship.

[0042] The following is attached to the instruction manual Figure 1-9 The embodiments of the present invention are described in further detail.

[0043] The embodiment of the present application discloses a radial dynamic pressure air bearing.

[0044] Reference Figure 1 and Figure 2, the radial dynamic pressure air bearing includes a bearing sleeve 1, a support assembly 3 and a top foil 6, wherein the top foil 6 and the support assembly 3 are sequentially arranged and installed in the bearing sleeve 1 from the inside to the outside. A connection area 62 is formed in the top foil 6, and the inner rotor 7 corresponding to the radial dynamic pressure air bearing can be inserted into the connection area 62. In this embodiment, when the radial dynamic pressure air bearing is in a working state, the inner rotor 7 rotates at a high speed in the connection area 62, and a dynamic pressure air film is formed between the inner rotor 7 and the top foil 6. The dynamic pressure air film can support the rotating inner rotor 7 and separate the inner rotor 7 from the top foil 6, thereby reducing the friction of the inner rotor 7 during the rotation process. For the convenience of description, the rotation direction of the inner rotor 7 is defined as from upstream to downstream below.

[0045] Reference Figure 1 and Figure 2 The inner and outer sides of the bearing sleeve 1 are both circular and coaxial. In order to prevent the support assembly 3 and / or the top foil 6 from detaching from the bearing sleeve 1 along the axial direction of the bearing sleeve 1, an annular bearing cover 8 is installed at the end of the bearing sleeve 1, wherein the bearing cover 8 is fixed to the bearing sleeve 1 by screws, and a sealing gasket (not shown in the figure) is arranged between the bearing cover 8 and the bearing sleeve 1.

[0046] Reference Figure 2 In order to improve the processing accuracy of the bearing sleeve 1 and reduce the processing cost of the bearing sleeve 1, the bearing sleeve 1 includes a plurality of outer sleeves 2 with the same cross-sectional shape and thickness. Each outer sleeve 2 is superimposed on each other along the axial direction of the bearing sleeve 1 and positioned by a spring pin, and is tightened and fixed by bolts to form a bearing sleeve 1 that is concentric inside and outside. Since the thickness of a single outer sleeve 2 is smaller than that of the bearing sleeve 1, the outer sleeve 2 has lower precision requirements on the processing equipment during processing and production, which reduces the cost of hardware equipment in the production process and improves the yield rate. In this embodiment, the outer sleeve 2 is 1 mm thick and is made of stainless steel. In other embodiments, the manufacturer can modify the material or size of the outer sleeve 2 according to actual needs.

[0047] Reference Figure 2 Furthermore, in order to ensure the consistency of the shapes of the outer sleeves 2, the outer sleeves 2 constituting any bearing sleeve 1 are all processed on the same equipment using the same processing parameters and are all processed in the same production batch. The above processing method is equivalent to processing the outer sleeves 2 at one time, so that the physical parameters of the outer sleeves 2, such as the outer ring cylindricity and the inner ring cylindricity, are as consistent as possible, thereby improving the overall processing accuracy of the bearing sleeve 1. In this embodiment, the outer sleeve 2 is processed and formed by laser cutting; in other embodiments, the manufacturer also uses other processing techniques, as long as the formed outer sleeve 2 can meet the actual product accuracy requirements.

[0048] Reference Figure 2In order to limit the support assembly 3 and / or the top foil 6 in the circumferential direction of the bearing sleeve 1, two retaining weirs 21 are arranged in the outer ring 2. The two retaining weirs 21 are arranged symmetrically with respect to the axis of the outer ring 2, and the positions of the retaining weirs 21 on each outer ring 2 are uniformly distributed. The mutually stacked retaining weirs 21 form two long strips of retaining bars 12 in the bearing sleeve 1. The retaining bars 12 are parallel to the axial direction of the bearing sleeve 1, and the two retaining bars 12 are distributed circumferentially around the inner side of the bearing sleeve 1. Two installation positions 13 are formed between the inner side of the bearing sleeve 1 and the two retaining bars 12. Both installation positions 13 can be used for assembling the support assembly 3 and / or the top foil 6.

[0049] Reference Figure 2 It can be understood that the number of retaining weirs 21 on each outer sleeve 2 is equal to the number of retaining bars 12 in the bearing sleeve 1, and the number of retaining bars 12 is equal to the number of mounting positions 13. In other embodiments, the number of retaining weirs 21 on each outer sleeve 2 can be 3, or other values ​​greater than 2. The manufacturer can modify the number of retaining weirs 21 according to the speed requirements and load requirements of the radial dynamic pressure air bearing. According to the analysis of multiple experimental data, the higher the speed requirement or load requirement, the greater the number of retaining weirs 21 required.

[0050] Reference Figure 3 and Figure 4 Specifically, two air guides corresponding to the two weirs 21 are arranged on the inner side of the outer ring 2, and each group of air guides includes two air guide grooves 22 arranged in pairs. The air guide grooves 22 are opened on the inner side of the outer ring 2 and connected to the two sides of the outer ring 2, so that the air guide grooves 22 on adjacent outer rings 2 are connected to each other, and two gas passages are formed on the inner side of the bearing sleeve 1, which are concave in the direction away from the axis of the outer ring 2 and extend axially of the outer ring 2. Any two corresponding air guide grooves 22 are arranged in a mirror image on a plane passing through the radial direction of the outer ring 2, and a distance is left between the two air guide grooves 22, so that a weir 21 is formed between the two air guide grooves 22. It can be understood that in other embodiments, if the number and position distribution of the weirs 21 change, the number and position distribution of the air guides will change with the weirs 21.

[0051] Reference Figure 3 Furthermore, a concave surface 221 is provided at the bottom of the air guide groove 22, and the concave surface 221 is tangent to the inner side of the outer sleeve 2. Both sides of the retaining weir 21 are perpendicular to the two adjacent concave surfaces 221, and a side of the retaining weir 21 close to the axis of the outer sleeve 2 is tangent to the inner side of the outer sleeve 2.

[0052] Reference Figure 4 The number of support components 3 is consistent with the number of mounting positions 13, and each support component 3 is arranged in one mounting position 13. When the radial dynamic pressure air bearing is not working, the inner rotor 7 (refer to Figure 1) is placed in the top foil 6 and contacts the top foil 6, and the support assembly 3 supports the top foil 6 so that there is space between the surface of the top foil 6 and the inner side of the bearing sleeve 1; when the radial dynamic pressure air bearing is working, a dynamic pressure air film will gradually form in the connection area 62, and the space between the surface of the top foil 6 and the inner side of the bearing sleeve 1 will gradually become smaller, and the support assembly 3 will gradually deform and always support the top foil 6. Therefore, as the main supporting component of the top foil 6, the support assembly 3 needs to meet not only the requirements of support stiffness, but also the requirements of deformation amount.

[0053] Reference Figure 4 Specifically, each group of support components 3 includes a plurality of elastic support springs 4 and a retainer 5 for fixing each support spring 4, wherein the retainer 5 is arc-shaped, and the two sides of the retainer 5 are respectively flush with the end faces of the two ends of the bearing sleeve 1, and the curvature of the retainer 5 matches the curvature of the bearing sleeve 1, and a distance is left between the retainer 5 and the inner side of the bearing sleeve 1 to accommodate each support spring 4. The two retainers 5 are respectively accommodated in the two mounting positions 13, and the ends of the retainers 5 are accommodated in the closest air guide groove 22 and contact the closest retaining weir 21, so that the two ends of the retainer 5 contact the retaining weir 21 respectively to limit the relative rotation between the retainer 5 and the bearing sleeve 1.

[0054] Reference Figure 4 , the keel 41 contacts the side of the retainer 5 close to the inner side of the bearing frame, and each support spring 4 is spaced apart along the arc surface of the retainer 5, so that all the support springs 4 are circumferentially distributed around the inner side of the bearing sleeve 1. In this embodiment, the hardness of the retainer 5 is greater than that of the support spring 4, and the retainer 5 is made of a metal material with good heat dissipation performance, the thickness of the retainer 5 is 0.05mm, and the thickness of the support spring 4 is 0.2mm; in other embodiments, the manufacturer can adjust the thickness of the retainer 5 or the thickness of the support spring 4 according to the speed requirements and load requirements of the radial dynamic pressure air bearing.

[0055] Reference Figure 5 Specifically, each supporting spring 4 includes a keel 41 and a plurality of supporting arms 42, the keel 41 and each supporting arm 42 are integrally formed, wherein the length direction of the keel 41 is parallel to the axial direction of the bearing sleeve 1, and the length of the keel 41 is consistent with the length of the bearing sleeve 1; each supporting arm 42 is spaced apart along the length direction of the keel 41, the middle part of each supporting arm 42 passes through the keel 41, each supporting arm 42 is perpendicular to the keel 41 when not bent, and the connection between the support arm 42 and the keel 41 forms a supporting portion 422.

[0056] Reference Figure 5, the support spring 4 is fixed to the retaining frame 5 through the keel 41, and the two ends of the support arm 42 abut against the inner side of the bearing sleeve 1; the support arm 42 forms a double-beam structure with both ends abutting against the inner wall of the bearing sleeve 1, providing damping and supporting force. Therefore, two abutting parts 421 are formed at the two ends of the support arm 42, and a gap is left between each abutting part 421 and the surface of the retaining frame 5, so that the support arm 42 can bend and deform when pushed by the retaining frame 5. Since the keel 41 is distributed in a circle around the inner side of the bearing sleeve 1, the abutting parts 421 are distributed in a circle around the inner side of the bearing sleeve 1; in order to make the layout of each abutting part 421 more uniform, the support arms 42 on adjacent keels 41 are staggered.

[0057] Reference Figure 5 and Figure 6 , when the dynamic pressure air film is gradually formed, the distance between the retainer 5 and the bearing sleeve 1 will gradually decrease for the position where the dynamic pressure air film is formed, and the retainer 5 will contact the support portion 422, so that the support portion 422 gradually moves in the direction away from the axis of the bearing sleeve 1, thereby reducing the distance between each contact portion 421 on the keel 41 and the retainer 5, that is, the support arm 42 is gradually bent as a whole; and in the process of the gradual bending of the support arm 42, the distance between the contact portions 421 located at both ends of the support arm 42 gradually decreases, resulting in the force required to maintain the support arm 42 to continue to deform gradually increasing, which is equivalent to the difficulty of deforming the support arm 42 gradually increasing. Therefore, in the process of the gradual bending of the support arm 42, that is, in the process of the gradual increase in the deformation of the support spring 4, the deformation difficulty of the support spring 4 also has a gradually increasing dynamic change, and at the same time, the support stiffness of the support spring 4 is also greater. It is understandable that when the radial dynamic pressure air bearing just starts to work, the pressure of the dynamic pressure air film is relatively small. As the dynamic pressure air film is gradually fully formed, the pressure of the dynamic pressure air film will gradually increase and tend to be stable.

[0058] Reference Figure 5 and Figure 7 Therefore, the pressure of the dynamic pressure air film also has a gradually increasing dynamic change, so that the formation process of the dynamic pressure air film and the deformation process of the support spring 4 reach a dynamic coordination. For example, when the dynamic pressure air film is just beginning to form, the support arm 42 is easy to deform so that the retaining frame 5 can be away from the inner rotor 7 in a shorter period of time, providing space for the flow of air more quickly, so that the dynamic pressure air film can be formed more quickly, continuously and stably.

[0059] Reference Figure 4 and Figure 6When the dynamic pressure air film has been fully formed, the support arm 42 is difficult to deform, so that the distance between the retaining frame 5 and the inner rotor 7 is relatively stable, thereby making the distribution of the dynamic pressure air film more stable, so that the dynamic pressure air film can support the inner rotor 7 more evenly, and improve the coaxiality between the inner rotor 7 and the bearing sleeve 1. At the same time, by utilizing the characteristic that the greater the force of the dynamic pressure air film, the greater the damping between the support spring 4 and the bearing sleeve 1, the support stiffness of the support spring 4 is further improved, and the load-bearing capacity and impact resistance of the radial dynamic pressure air bearing are improved. The two ends of the support arm 42 in this solution are rectangular as a whole, but this solution does not limit the parallel relationship between the two sides of the support arm 42. The manufacturer can change the shape of the support arm 42 according to the support stiffness requirements of the support arm 42, such as a trapezoid.

[0060] Reference Figure 5 and Figure 6 Furthermore, the end face of the resistance part 421 is provided with an arcuate surface. When the support arm 42 is bent, the resistance part 421 will slide relative to the inner wall of the bearing sleeve 1. At this time, the resistance part 421 can resist the bearing sleeve 1 through the edge provided with the arcuate surface. On the one hand, the contact between the resistance part 421 and the bearing sleeve 1 can form point-to-surface contact, reduce the contact area, and reduce the risk of the resistance part 421 moving under non-dynamic air film pressure; on the other hand, the arcuate surface can reduce the sharpness of the edge of the resistance part 421 and reduce the wear between the resistance part 421 and the bearing sleeve 1.

[0061] Reference Figure 5 Specifically, a separation space 423 is formed between any two adjacent support arms 42, and the retainer 5 is provided with a plurality of clamping pieces 51 capable of clamping the keel 41 in the separation space 423. In order to reduce the risk of the keel 41 deviating from the axial direction of the bearing sleeve 1, each separation space 423 is provided with two clamping pieces 51, and the clamping pieces 51 arranged on both sides of the same keel 41 are symmetrically arranged with a plane passing through the geometric center of the keel 41 and the axis of the bearing sleeve 1, and the two clamping pieces 51 respectively contact the two sides of the keel 41. In this embodiment, in order to improve the stability of the keel 41, if the distance between the end face of any end of the keel 41 and the closest support arm 42 on the keel 41 is less than or equal to the minimum width of the separation space 423, the end of the keel 41 is also provided with a clamping piece 51.

[0062] Reference Figure 8 In order to form each clamping piece 51, a plurality of slits 52 corresponding to each clamping piece 51 are provided on the retaining frame 5, and the slits 52 are formed on the retaining frame 5 by a cutting process such as a laser cutting process. The slits 52 include a first slit 521 and two second slits 522 both forming angles with the first slit 521, wherein the first slit 521 corresponds to the end of the clamping piece 51, and the two second slits 522 correspond to the two sides of the clamping piece 51 respectively.

[0063] Reference Figure 8 and Fig. 9 When the retainer 5 is bent, the portion of the retainer 5 located in the first slit 521 and the two second slits 522 will be dislocated and separated from the other portions of the retainer 5 to form a clamping piece 51, and a through hole is formed at the position of the slit portion 52. One end of the clamping piece 51 away from the first slit 521 is fixed to the retainer 5, and the other end of the clamping piece 51 is tilted, so that a clamping space for accommodating the keel 41 is formed between the clamping piece 51 and the retainer 5.

[0064] Reference Figure 8 , the two slits 52 corresponding to the two symmetrically arranged clamping pieces 51 are also symmetrical to each other. In this embodiment, in order to reduce production costs, the two symmetrical slits 52 share a first slit 521, and the two second slits 522 of the two symmetrical slits 52 are distributed one-to-one and connected, so that the overall shape of the two symmetrical slits 52 can be "H" shaped. It is worth noting that this solution does not limit the shape of the clamping piece 51. In other embodiments, the clamping piece 51 can also be a trapezoid, a half waist or a triangle. The manufacturer can modify it according to the actual rigidity requirements of the clamping piece 51, and the shape of the slit 52 also corresponds to the shape of the clamping piece 51.

[0065] Reference Figure 8 and Fig. 9 When processing the retainer 5, the retainer 5 can be cut out as a whole, and then each slit portion 52 is cut on the retainer 5, and then the retainer 5 is bent so that each clamping piece 51 is tilted to form each clamping space. Subsequently, the keel 41 can be clamped in each corresponding clamping space so that the clamping piece 51 and the retainer 5 are in contact with the keel 41. Since each clamping piece 51 is symmetrically arranged on both sides of the keel 41 to limit the swing of the keel 41, the keel 41 and the retainer 5 are relatively fixed. The fixing method between the keel 41 and the clamping piece 51 is simple and direct, which is convenient for production, reduces production costs, and improves production efficiency; on the other hand, the keel 41 and the clamping piece 51 can be disassembled and repeatedly installed, which is convenient for operators to perform maintenance and reduces maintenance costs. At the same time, since the retaining frame 5 fixes the keel 41 of the support spring 4 through the clamping plate 51, the operator can use the same retaining frame 5 in combination with the support spring 4 with different shapes of support arms 42 for testing or experiments during the development and testing process, which is convenient for development experiments and improves the scalability of the radial dynamic pressure air bearing.

[0066] Reference Figure 4On the other hand, when the radial dynamic pressure air bearing is working, especially when friction occurs between the inner rotor 7 and the top foil 6, the top foil 6 will generate a large amount of heat. Since the contact area between the top foil 6 and the retaining frame 5 is large, most of the heat of the top foil 6 will be quickly transferred to the retaining frame 5, and each clamping sheet 51 can increase the contact area between the retaining frame 5 and the air, thereby improving the heat dissipation speed of the retaining frame 5, and thereby improving the heat dissipation speed of the top foil 6.

[0067] Reference Figure 4 and Figure 6 Furthermore, since the clamping piece 51 is equivalent to applying force to the keel 41 from multiple directions to fix the keel 41 relatively to the retaining frame 5, there is always a certain degree of mobility between the keel 41 and the retaining frame 5, which may cause the keel 41 to deviate from its position. In order to enable the keel 41 to maintain a state parallel to the axial direction of the bearing sleeve 1 when in the working state, the distance between each abutment portion 421 and the axis of the bearing sleeve 1 is consistent, and the keel 41 passes through the geometric center of each corresponding support arm 42. Taking any one of the keels 41 and the corresponding support arms 42 as an example, when the keel 41 is in a normal state, each abutment portion 421 abuts against the inner side of the bearing sleeve 1, and at this time, the two ends of the support arm 42 are in a state of force balance.

[0068] Reference Figure 4 and Figure 6 When the keel 41 is in a position deviation state, part of the contact part 421 will contact the inner side of the bearing sleeve 1, while part of the contact part 421 will fit the inner side of the bearing sleeve 1 or directly separate from the inner side of the bearing sleeve 1, resulting in a larger force between the part of the contact part 421 and the inner side of the bearing sleeve 1, and a smaller force between the part of the contact part 421 and the inner side of the bearing sleeve 1. At this time, part of the support arm 42 will be in a state of unbalanced force; when the dynamic pressure air film begins to form, the retaining frame 5 will push each support arm 42, so that the two ends of the support arm 42 further contact the inner side of the bearing sleeve 1. Under the action of the decomposition of the arc surface force of the bearing sleeve 1, the support arm 42 as a whole will move from the end with stronger force effect to the end with weaker force effect, so that each support arm 42 gradually moves to a state of balanced force at both ends, so that the keel 41 gradually returns to a state parallel to the axial direction of the bearing sleeve 1, and the process of the support arm 42 gradually returning to the state of balanced force at both ends is equivalent to the process of the support arm 42 completing automatic centering.

[0069] Reference Figure 4It can be understood that the pressure generated by the dynamic pressure air film on the top foil 6 is related to the effective area of ​​the dynamic pressure air film, and the effective area is related to the support of the top foil 6. For the dynamic pressure air film, the more stable and uniform support each support arm 42 can provide, the more stable the pressure of the dynamic pressure air film. The automatic centering process of the support arm 42 is equivalent to the process of the support arm 42 automatically returning to a more ideal support state after the start of work, so that even if the support arm 42 is partially offset, it can still provide relatively stable support after the working state, reducing the requirements for the position accuracy of each support arm 42 and improving the working stability of the radial dynamic pressure air bearing.

[0070] Reference Figure 4 Specifically, the number of top foils 6 is 2, and the two top foils 6 correspond to the two retaining frames 5 one by one. The top foils 6 are closely attached to the side of the retaining frame 5 away from the support arm 42, and the length and width of the top foils 6 match the length and width of the retaining frame 5. The two top foils 6 are respectively accommodated in the two mounting positions 13, and the middle parts of the two top foils 6 form a connection area 62 that is circular as a whole, for the inner rotor 7 to insert; the two ends of the top foil 6 are respectively accommodated in the closest air guide groove 22, and respectively contact the closest retaining weir 21. In this embodiment, each retaining weir 21 fixes the top foil 6 and the retaining frame 5 at the same time, without welding, thereby improving the maintainability of the radial dynamic pressure air bearing.

[0071] Reference Figure 3 and Figure 4 Due to the setting of the concave surface 221, the end of the top foil 6 entering the air guide groove 22 can deviate from the connection area 62, so that the end of the top foil 6 close to the connection area 62 forms an air guide wedge surface 61, and the air guide wedge surface 61 is tangent to the connection area 62.

[0072] Reference Figure 5 and Figure 7 When the inner rotor 7 is installed in the connection area 62 and the inner rotor 7 does not start to rotate, the outer peripheral wall of the inner rotor 7 contacts the top foil 6, and a gap may be left between the air guide wedge surface 61 and the outer peripheral wall of the inner rotor 7. At the same time, since the side of the retaining weir 21 close to the inner rotor 7 is tangent to the inner side of the bearing sleeve 1, there is also a gap between the retaining weir 21 and the inner rotor 7, so that an initial air guide port 14 is formed between the air guide wedge surface 61, the retaining weir 21 and the inner rotor 7, and the air outside the radial dynamic pressure air bearing can first enter between the top foil 6 and the inner rotor 7 through the initial air guide port 14. In addition, a gas channel extending along the axial direction of the bearing sleeve 1 is formed between each initial air guide port 14 to reduce the friction caused by the direct contact between the retaining weir 21 and the inner rotor 7.

[0073] Reference Figure 5 and Figure 7When the inner rotor 7 starts to rotate, the air in the initial air guide port 14 can move between the top foil 6 and the inner rotor 7 along the rotation direction of the inner rotor 7 and have kinetic energy, thus smoothly forming a part of the dynamic pressure air film, and the air guide wedge surface 61 can make the air flow in the above process smoother, reduce the occurrence of the air forming vortex at the beginning, and thus reduce the takeoff speed of the inner rotor 7. In the process of the dynamic pressure air film gradually forming, the top foil 6 is close to the retaining frame 5, and a plurality of pits (not shown in the figure) are formed on the surface to reduce gas leakage, make the pressure of the dynamic pressure air film more stable, and increase the effective contact area of ​​the top foil 6, thereby improving the load-bearing capacity of the radial dynamic pressure air bearing.

[0074] Reference Figure 5 and Figure 7 It is worth noting that since the main force points between each supporting spring 4 and the retaining frame 5 are distributed on each supporting portion 422, and the supporting portions 422 on adjacent keels 41 are staggered, each supporting portion 422 can form a number of supporting areas that pass through four supporting portions 422 and are diamond-shaped as a whole. The formation of each supporting area can make the support of the top foil 6 by the support assembly 3 more uniform, thereby making the effective contact area between the top foil 6 and the dynamic pressure air film more uniform, providing a more uniform support stiffness distribution, so that the rotating inner rotor 7 can maintain a good coaxiality with the bearing sleeve 1, and reducing the loss of the inner rotor 7 caused by deviation from the axis in the working state.

[0075] Reference Figure 5 and Figure 7 On the other hand, since the lengths of the support arms 42 are consistent and the inner and outer sides of the bearing sleeve 1 are coaxial, the connecting area 62 is coaxial with the inner side of the bearing sleeve 1. Therefore, when the inner rotor 7 is installed in the connecting area 62 and does not rotate, the inner rotor 7 can also maintain good coaxiality with the bearing sleeve 1.

[0076] Reference Figure 5 and Figure 7, further, the two ends of the retainer 5 form an upstream end 53 and a downstream end 54, respectively, and the upstream end 53 and the downstream end 54 are respectively accommodated in the closest air guide groove 22. When the inner rotor 7 is in a rotating state, any point on the inner rotor 7 follows the rotation direction and passes through the upstream end 53 and the downstream end 54 of the same retainer 5 in sequence. The width of the support arms 42 on each keel 41 located on the same retainer 5 has a changing trend. Specifically, the width of the support arms 42 on each keel 41 gradually increases from the upstream end 53 to the downstream end 54, that is, the width of each separation space 423 on the same retainer 5 gradually decreases from the upstream end 53 to the downstream end 54. This changing trend, on the one hand, makes the deformation difficulty of each support arm 42 on the retainer 5 gradually increase from the upstream end 53 to the downstream end 54, and on the other hand, makes the density of the contact points between the retainer 5 and each support portion 422 gradually increase from the upstream end 53 to the downstream end 54.

[0077] Reference Figure 5 and Figure 7 It can be understood that when the dynamic pressure air film is gradually formed, the kinetic energy of the dynamic pressure air film will gradually increase, and the force provided by the dynamic pressure air film will also gradually increase; and because the air first enters between the top foil 6 and the inner rotor 7 through the initial air guide port 14, and moves along the rotation direction of the inner rotor 7, the pressure of the dynamic pressure air film has a tendency to gradually increase from the upstream of the inner rotor 7 to the downstream of the inner rotor 7 during the gradual formation of the dynamic pressure air film. In conjunction with the tendency that the deformation difficulty of each support arm 42 gradually increases from the upstream end 53 to the downstream end 54, the support arm 42 can provide a smaller deformation difficulty when the dynamic pressure air film pressure is small, and provide a larger deformation difficulty when the dynamic pressure air film pressure is large, so that the deformation degree of each support arm 42 in the bearing sleeve 1 tends to be balanced, so that the inner rotor 7 obtains more uniform support, and improves the coaxiality between the inner rotor 7 and the bearing sleeve 1 after the dynamic pressure air film is formed.

[0078] Reference Figure 5 and Figure 7 When the dynamic pressure air film begins to form, the support arms 42 close to the upstream end 53 are more likely to deform, and the retaining frame 5 is more easily pushed by the dynamic pressure air film, further increasing the speed of leaving space between the top foil 6 and the inner rotor 7, thereby lowering the take-off speed of the radial dynamic pressure air bearing.

[0079] Reference Figure 5 and Figure 7 Specifically, when the radial dynamic pressure air bearing in this embodiment is installed, the two retainers 5 are distributed up and down, and even the two groups of support springs 4 located on the two retainers 5 are also distributed up and down. In a natural state, the inner rotor 7 will press down the retainer 5 under the action of gravity, so that each support arm 42 located below has a tendency to deform.

[0080] Reference Figure 5 and Figure 7 For the convenience of description, the n support springs 4 near the lower downstream end 54 are defined as support springs 4a, and the n support springs 4 near the upper downstream end 54 are defined as support springs 4b, where n=3. It can be understood that the value of n is 3, which is just one example of the present solution, and does not impose an absolute limitation on the value of n.

[0081] Reference Figure 5 and Figure 7 For each support arm 42 located at the bottom, since each support arm 42 located on the support spring 4a has a relatively large support rigidity, the lower part of the inner rotor 7 will be subjected to an unbalanced force, resulting in the inner rotor 7 having a tendency to move toward the support spring 4b as a whole. For each support arm 42 located at the top, since each support arm 42 located on the support spring 4b also has a relatively large support rigidity, it can also provide a certain support for the inner rotor 7.

[0082] Reference Figure 5 and Figure 7 Therefore, the thrust Fa of the support spring 4a on the inner rotor 7 and the thrust Fb of the support spring 4b on the inner rotor 7 can reach a relatively balanced state in the tilting direction, thereby providing relatively uniform support, compensating for the lack of uneven support of the inner rotor 7 in the vertical direction, and maintaining good coaxiality between the inner rotor 7 and the bearing sleeve 1.

[0083] Reference Figure 1 and Figure 2 When the radial dynamic pressure air bearing just starts to work or the inner rotor 7 is about to stop rotating, the force provided by the dynamic pressure air film is small, and friction will occur between the inner rotor 7 and the top foil 6. In order to reduce the wear and heat between the inner rotor 7 and the top foil 6, the surface of the top foil 6 is coated with a solid lubricating coating. As the working time increases, the inner rotor 7 will wear the solid lubricating layer to form solid lubricating powder. In order to reduce the leakage of the worn solid lubricating powder and make the solid lubricating powder recyclable, the bearing cover 8 blocks part of the air guide groove 22. It can be understood that under the pressure of the dynamic pressure air film and the centrifugal force, the solid lubricating powder will gather on both sides of the retaining weir 21 and between the corresponding air guide wedge surfaces 61, and the bearing cover 8 can partially block the air guide groove 22, thereby reducing the leakage of the solid lubricating powder.

[0084] Reference Figure 1 and Figure 2 On the other hand, in order to reduce the probability of friction between the inner side of the bearing cover 8 and the outer peripheral wall of the inner rotor 7 while maintaining the air flowability at the initial air guide port 14, the inner side of the bearing cover 8 is tangent to the side of the retaining weir 21 away from the inner wall of the bearing sleeve 1.

[0085] The implementation principle of the radial dynamic pressure air bearing of the present application is as follows: Since the rotation speed of the radial dynamic pressure air bearing is relatively large compared with that of the traditional ball bearing, the radial dynamic pressure air bearing has relatively high requirements on the coaxiality of the inner and outer sides of the bearing sleeve 1, the slotting accuracy of the inner side of the bearing sleeve 1 and other processing parameters. The bearing sleeve 1 in the present scheme is composed of a plurality of outer sleeves 2 with relatively small thickness, and the bearing sleeve 1 is formed by first cutting the outer sleeve 2 with relatively small processing difficulty and then assembling each outer sleeve 2, thereby reducing the processing difficulty of the bearing sleeve 1, and further reducing the research and development cost, experimental cost and production cost of the radial dynamic pressure air bearing. Each outer sleeve 2 is cut and formed at one time, so that the inner cylindricality, outer cylindricality, inclination of the air guide groove 22 and shape of the retaining weir 21 of the outer sleeve 2 can be as consistent as possible, thereby improving the coaxiality of the inner and outer sides of the bearing sleeve 1, the straightness of the gas channel formed by each air guide groove 22, and the straightness of the retaining bar 12 formed by each retaining weir 21.

[0086] The end of the top foil 6 and the end of the retaining frame 5 can be arranged in the corresponding air guide groove 22, so that the top foil 6 forms an air guide wedge surface 61, and an initial air guide port 14 can be formed between the top foil 6 and the inner rotor 7, so that air can enter between the top foil 6 and the inner rotor 7 to obtain kinetic energy, and the setting direction of the air guide wedge surface 61 can reduce the probability of gas vortex generation, make the gas flow smoother, and thus accelerate the formation rate of the dynamic pressure gas model to achieve a lower take-off speed.

[0087] The top foil 6 and the retaining frame 5 are fixed in the corresponding installation position 13 under the limiting action of each retaining dam 21 to prevent the top foil 6 and / or the retaining frame 5 from moving along the circumferential direction of the bearing sleeve 1. The top foil 6 and the retaining frame 5 do not need to be welded in the bearing sleeve 1, thereby making the assembly of the radial dynamic pressure air bearing simpler and the maintainability of the radial dynamic pressure air bearing higher.

[0088] Each support spring 4 is clamped and fixed on the retaining frame 5 by a clamping piece 51, which is a detachable fixing method, so that the operator can install or replace the support spring 4 conveniently; when designing the radial dynamic pressure air bearing, the manufacturer can modify the width, quantity, shape and material of the support spring 4, change the support stiffness distribution of the top foil 6, so that the radial dynamic pressure air bearing can obtain different strengths.

[0089] On the other hand, the support component 3 is composed of a support spring 4 and a retaining frame 5. The support component 3 can use materials of different materials according to the specific functions of each part, wherein the support spring 4 is mainly used to complete the conversion between elastic potential energy and kinetic energy, and the retaining frame 5 is mainly used to fix the top foil 6. Therefore, in this embodiment, the hardness of the top foil 6 is greater than the hardness of the support spring 4, so that the support component 3 has sufficient support stiffness while having a deformation amount that meets the requirements, and makes the support component 3 more expandable.

[0090] Since there is always a certain degree of freedom between the keel 41 and the clamping plate 51, when the radial dynamic pressure air bearing is working, as the dynamic pressure air film is formed, some of the support springs 4 that have deviated from their positions can be automatically centered to ensure that the top foil 6 can be evenly supported, thereby reducing the requirements for the position accuracy of each support arm 42 and improving the working stability of the radial dynamic pressure air bearing.

[0091] When the inner rotor 7 is installed in the connection area 62, since the lengths of the support arms 42 are consistent, the connection area 62 is coaxial with the bearing sleeve 1, and the inner rotor 7 and the bearing sleeve 1 can achieve good coaxiality.

[0092] Since the overall force of the dynamic pressure air film gradually increases during the process from the initial formation to the stable formation, the formation process of the dynamic pressure air film and the deformation process of the support spring 4 are dynamically coordinated by utilizing the characteristics that the deformation difficulty and support stiffness of each support spring 4 increase with the increase of deformation amount.

[0093] When the dynamic pressure air film just begins to form, since the support arm 42 is easy to deform, space for the formation of the dynamic pressure air film can be quickly reserved in the radial dynamic pressure air bearing, reducing the limitation of space on the formation of the dynamic pressure air film so that the dynamic pressure air film can be formed continuously and stably, achieving a lower takeoff speed. At the same time, since the support arm 42 has a good impact load absorption capacity when the dynamic pressure air film just begins to form, the impact of the inner rotor 7 on the radial foil dynamic pressure air bearing is reduced, and the working stability of the radial foil dynamic pressure air bearing is improved.

[0094] Since the support stiffness of the support arm 42 increases with the increase in the deformation, when the dynamic pressure air film has been formed, the support arm 42 can still provide a large support stiffness. By utilizing the characteristic that the greater the force of the dynamic pressure air film, the greater the damping between the support arm 42 and the bearing sleeve 1, the support stiffness of the support spring 4 can be further improved, thereby improving the load-bearing capacity and impact resistance of the radial dynamic pressure air bearing.

[0095] As the force of the dynamic pressure air film gradually increases, the change of the force of the dynamic pressure air film will proceed along the rotation direction of the inner rotor 7. By utilizing the change trend of the width of each support arm 42 from the upstream end 53 to the downstream end 54, the support arm 42 can provide a smaller deformation difficulty when the pressure of the dynamic pressure air film is small, and provide a larger deformation difficulty when the pressure of the dynamic pressure air film is large, so that the deformation degree of each support arm 42 in the bearing sleeve 1 tends to be balanced, so that the inner rotor 7 obtains more uniform support, and improves the coaxiality between the inner rotor 7 and the bearing sleeve 1. In addition, when the dynamic pressure air film is just beginning to form, the support arms 42 close to the upstream end 53 are more likely to deform, and the retaining frame 5 is more easily pushed by the dynamic pressure air film, so that the take-off speed of the radial dynamic pressure air bearing is lower.

[0096] In combination with the above-mentioned distribution of the dynamic pressure air film pressure field when the radial dynamic pressure air bearing is working and the dynamic change characteristics of the dynamic pressure air film pressure field, this scheme reasonably sets the support spring 4, and accurately arranges the support spring 4 with appropriate stiffness in sequence on the retaining frame 5, so as to provide relatively uniform support stiffness in the three stages of the dynamic pressure air film not being formed, the dynamic pressure air film beginning to form, and the dynamic pressure air film being stably formed, thereby improving the coaxiality of the inner rotor 7 and the radial dynamic pressure air bearing, reducing the negative impact of manufacturing tolerances on the stability and reliability of the radial dynamic pressure air bearing, and making the production and use costs of the radial dynamic pressure air bearing lower.

[0097] The above are all preferred embodiments of the present application, and the protection scope of the present application is not limited thereto. Therefore, any equivalent changes made according to the structure, shape, and principle of the present application should be included in the protection scope of the present application.

Claims

1. A radial dynamic pressure air bearing, comprising a bearing sleeve (1) and at least one support assembly (3), characterized in that: The support assembly (3) comprises a retaining frame (5) arranged in the bearing sleeve (1) and at least one elastic support arm (42), a distance being left between the retaining frame (5) and the bearing sleeve (1), the support arm (42) being arranged between the bearing sleeve (1) and the retaining frame (5), the support arm (42) being provided with at least two abutting portions (421) for abutting against the inner wall of the bearing sleeve (1), each of the abutting portions (421) being distributed in a circumferential manner around the retaining frame (5), and a gap being left between the abutting portions (421) and the retaining frame (5) so that the abutting portions (421) can be deformed; The support assembly (3) further comprises at least two keels (41) distributed in a circumference around the retaining frame (5), each support arm (42) being arranged on the keel (41) at intervals, the retaining frame (5) being provided with at least two clamping pieces (51) arranged on both sides of the keel (41) and capable of contacting the keel (41), and a distance being left between the clamping piece (51) and the retaining frame (5) to form a clamping space for accommodating the keel (41); The retaining frame (5) is provided with a slit portion (52) for forming the clamping piece (51) and dividing the retaining frame (5); the slit portion (52) comprises a first slit (521) corresponding to the end of the clamping piece (51) and a second slit (522) corresponding to the two sides of the clamping piece (51); an angle is formed between the first slit (521) and the second slit (522); the retaining frame (5) is capable of bending to separate the clamping piece (51) from the slit portion (52); The bearing sleeve (1) comprises at least two outer sleeve rings (2) which are distributed along the radial direction and are coaxially arranged; each of the outer sleeve rings (2) overlaps each other along the axial direction of the bearing sleeve (1) to form the outer sleeve ring (2); The radial dynamic pressure air bearing further comprises a top foil (6), wherein the top foil (6) is arranged on a side of the retaining frame (5) away from the support arm (42), and each of the support arms (42) on two adjacent keels (41) is staggeredly distributed; The space between two adjacent support arms (42) on the same keel (41) forms a separation space (423); the two ends of the retaining frame (5) form an upstream end (53) and a downstream end (54) along the rotation direction of the radial dynamic pressure air bearing; the minimum width of the separation space (423) gradually increases from the downstream end (54) to the upstream end (53); the width of the support arm (42) on each keel (41) gradually increases from the upstream end (53) to the downstream end (54); and the end of the bearing sleeve (1) is provided with a ring-shaped bearing cover (8); At least one retaining weir (21) is arranged in the bearing sleeve (1); the number of the retaining frames (5) corresponds to the number of the retaining weirs (21); a mounting position (13) for mounting one of the retaining frames (5) is formed between the two sides of one of the retaining weirs (21) and the inner side of the bearing sleeve (1) and / or between the two closest retaining weirs (21) and the inner side of the bearing sleeve (1); both ends of the retaining frame (5) can abut against the retaining weir (21) closest to it; The bearing sleeve (1) is provided with an air guide portion corresponding to the retaining weir (21) one by one, the air guide portion comprising at least two air guide grooves (22) distributed at intervals, and a retaining weir (21) is formed between the two closest air guide grooves (22); the radial dynamic pressure air bearing also comprises a top foil (6) arranged in the mounting position (13), and the two ends of the top foil (6) are respectively accommodated in the two closest air guide grooves (22) abutting against each other.

2. The radial dynamic pressure air bearing according to claim 1, characterized in that: The keel (41) is arranged along the axial direction of the bearing sleeve (1), and the minimum distance between each of the abutment portions (421) and the axis of the bearing sleeve (1) is equal; and each of the clamping pieces (51) located on the same keel (41) is symmetrically arranged on both sides of the keel (41).

3. The radial dynamic pressure air bearing according to claim 1, characterized in that: An air guide wedge surface (61) is provided at the end of the top foil (6) close to the air guide groove (22), and a connection area (62) capable of installing an inner rotor (7) is provided in the bearing sleeve (1), and the air guide wedge surface (61) is tangent to the connection area (62).

Images