A double-layer flat foil radial bearing

Abstract

The present invention relates to a double-layer flat foil radial bearing, comprising a bearing seat, a B-type pin, a top layer of flat foil, a middle layer of flat foil, and a bottom layer of corrugated foil. The bearing seat is provided with a mounting slot into which the B-type pin is inserted. The main bodies of the middle and top layers of flat foil are bent and positioned within the bearing seat. The fixed ends of the middle and top layers of flat foil extend into the mounting slot and are fixedly connected to the flat side of the B-type pin. The arc surface of the B-type pin cooperates with the arc-shaped limiting surface of the mounting slot. The bottom layer of corrugated foil is fixedly connected to the middle layer of flat foil. The two end faces of the fixed ends of the middle and top layers of flat foil are respectively flush with the axial end faces of their corresponding B-type pins. The end faces on both sides of the fixed ends of the middle and top layers of flat foil are lower than the axial end faces of their corresponding bearing seat. The present invention enables the radial foil bearing to utilize the cooperation of the B-type pin and the bearing seat for radial positioning and blocking, and prevents radial vibration of the foil, thereby greatly improving the reliability of the bearing and preventing failures.

Description

Technical Field

[0001] The invention belongs to the technical field of gas bearings, and in particular relates to a double-layer flat foil radial bearing. Background Art

[0002] With the rapid development of high-speed turbines, aerospace, precision instruments, and other fields, rotating machinery has placed higher demands on bearing speed and stability. Therefore, research into oil-free gas lubrication technology is crucial. GFBs (gas foil bearings) offer high operating speeds, a wide operating temperature range, low friction, excellent stability, and an extremely long service life, all while being lubricated using gas. Therefore, they are widely used in rotor bearings for high-speed rotating machinery. They require no gas supply equipment and are the simplest bearing system.

[0003] See also Figure 1 As shown, the structure of the slot-type radial foil bearing in the prior art includes a bearing seat 1, a corrugated foil 2, a flat foil 3 and a pin 4, wherein the fixed ends of the corrugated foil 2 and the flat foil 3 are bent and extended into the mounting groove of the bearing seat 1 and fixed by the pin 4.

[0004] During the actual use of gas foil bearings, due to the manufacturing precision and installation errors of the bearings, the foil of ordinary slot-type gas foil bearings will displace along the radial direction of the bearing mounting slot, causing wear between the foil and the bearing seat, and may even cause failure of the entire machine. Summary of the Invention

[0005] In order to solve the technical problem in the prior art that the foil of a common slot-type foil bearing is prone to radial vibration along the mounting slot of a bearing seat, the present invention provides a double-layer flat foil radial bearing.

[0006] The technical solution of the present invention to solve the above problems is: a double-layer flat foil radial bearing, which is special in that:

[0007] The invention comprises a bearing seat, a B-type pin, a top flat foil, a middle flat foil, and a bottom corrugated foil. The bearing seat is provided with a mounting groove into which the B-type pin is inserted. The mounting groove is provided with an arc-shaped limiting surface that cooperates with the arc surface of the B-type pin. The main parts of the middle and top flat foils are bent and positioned within the bearing seat. One end of the middle and top flat foils is bent, and the formed bent edges serve as fixed ends that fit together and extend into the mounting groove of the bearing seat. The fixed ends are fixedly connected to the flat side of the B-type pin. The bottom corrugated foil is fixedly connected to the main part of the middle flat foil. The two end faces of the fixed ends of the middle and top flat foils are respectively flush with the axial end faces of their corresponding B-type pins. The end faces on both sides of the fixed ends of the middle and top flat foils are lower than the corresponding axial end faces of the bearing seat.

[0008] Furthermore, the vertical length of the plane side of the above-mentioned B-type pin is slightly smaller than the vertical length of the plane side of the bearing seat positioning groove, thereby preventing the B-type pin from extending out of the positioning groove and interfering with the foil.

[0009] Furthermore, the main parts of the top layer flat foil and the middle layer flat foil are coaxially arranged, with their axial end faces flush, and the inner diameter of the middle layer flat foil is slightly smaller than that of the top layer flat foil.

[0010] Furthermore, the thickness of the main body of the middle layer flat foil is greater in the middle portion than in the two sides along the circumferential direction. The middle portion is a high-rigidity area, and the two sides are low-rigidity areas.

[0011] Furthermore, the thickness of the high-rigidity region in the middle-layer flat foil is 0.2 mm, and the thickness of the low-rigidity region is 0.1 mm.

[0012] Furthermore, the middle layer flat foil is provided with slits distributed in the axial direction and extending in the circumferential direction.

[0013] Furthermore, there are three bottom corrugated foils, which are evenly fixed to the middle flat foil along the circumferential direction, and the spacing between two adjacent bottom corrugated foils is 2 mm.

[0014] Furthermore, in order to facilitate welding, the corrugated arch of the first bottom corrugated foil close to the fixed end is arranged outward so that the corrugated arch is in close contact with the bearing seat.

[0015] Furthermore, the bottom corrugated foil is provided with slits distributed in the axial direction and extending in the circumferential direction, so as to adjust the structural stiffness of the radial bearing and prevent stress concentration.

[0016] Furthermore, the end surfaces on both sides of the fixed ends of the middle and top flat foils are respectively 0.5 mm lower than the corresponding axial end surfaces of the bearing seats.

[0017] Advantages of the present invention:

[0018] 1) The double-layer flat foil radial bearing proposed in the present invention utilizes B-type pins to cooperate with the bearing seat for radial positioning and blocking, and prevents radial vibration of the foil, thereby greatly increasing the reliability of the bearing and preventing failures.

[0019] 2) The double-layer flat foil radial bearing proposed in this invention can adjust the structural stiffness of the radial foil bearing and prevent stress concentration. By changing the thickness of the middle flat foil to adjust the lubrication gap, it can better absorb the rotor vibration energy and improve the stability of the rotor system.

[0020] 3) The double-layer flat foil structure proposed in the present invention allows the corrugated foil to be directly welded to the middle flat foil without adding other auxiliary devices, which provides convenience for bearing installation;

[0021] 4) The double-layer flat foil structure proposed in the present invention also has the characteristics of low processing cost, low difficulty and strong applicability. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a structural diagram of a slot-type radial foil bearing in the prior art;

[0023] Figure 2 It is a side view of a radial bearing with double flat foil;

[0024] Figure 3 It is a schematic diagram of the partial structure of a double-layer flat foil radial bearing;

[0025] Figure 4 It is a schematic diagram of the three-dimensional structure of a double-layer flat foil radial bearing;

[0026] Figure 5 It is a structural diagram of the bearing seat;

[0027] Figure 6 It is a schematic diagram of the structure of type B pin;

[0028] Figure 7 is a schematic diagram of an embodiment of a bottom wave foil;

[0029] Figure 8 This is a schematic structural diagram of an embodiment of a middle-layer flat foil;

[0030] Figure 9 1 is a schematic structural diagram of an embodiment of a top flat foil;

[0031] Figure 10 This is a schematic diagram of the second middle-layer flat foil structure provided by the present invention;

[0032] Figure 11 This is a schematic diagram of the third middle-layer flat foil provided by the present invention before stamping;

[0033] Figure 12 This is a schematic diagram of the structure of the third type of middle layer flat foil after forming;

[0034] Among them: 1-bearing seat; 2-bottom layer corrugated foil; 3-middle layer flat foil; 4-b-type pin; 5-top layer flat foil. DETAILED DESCRIPTION

[0035] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions 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 making creative work are within the scope of protection of the present invention. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the invention for which protection is claimed, but merely represents selected embodiments of the present invention.

[0036] See also Figure 2-4 The present invention provides a double-layer flat foil radial bearing, comprising a bearing seat 1, a b-type pin 4, a top flat foil 5, a middle flat foil 3 and a bottom corrugated foil 2. Figure 6 As shown, the b-type pin 4 includes a plane side and an arc side. Figure 5 As shown, the radial bearing seat 1 is cylindrical in structure, and its outer edge is circumferentially provided with screw holes for securing the bearing seat 1. A mounting slot is provided within the bearing seat 1, into which a B-type pin 4 is inserted. One side of the mounting slot features an arcuate stopper surface that mates with the arcuate surface of the B-type pin 4. The vertical length of the flat side of the B-type pin 4 is slightly shorter than the vertical length of the flat side of the positioning slot in the bearing seat 1, preventing the B-type pin 4 from extending out of the positioning slot and interfering with the foil. The middle and top flat foils 3 and 5 comprise a main body and a fixed end. The main bodies of the middle and top flat foils 3 and 5 are bent and positioned within the bearing seat 1. One end of the middle and top flat foils 3 and 5 is bent, forming a bent edge that fits together as a fixed end and extends into the mounting slot of the bearing seat 1. The fixed end is affixed to the flat side of the B-type pin 4, and the arcuate surface of the B-type pin 4 mates with the arcuate stopper surface of the mounting slot. The bottom corrugated foil 2 is uniformly welded to the main part of the middle flat foil 3 along the circumferential direction; in order to facilitate welding, the first corrugated arch of the bottom corrugated foil 2 close to the fixed end is arranged outward so that the corrugated arch is close to the bearing seat 1.

[0037] As a preferred embodiment of the present invention, the main parts of the top flat foil 5 and the middle flat foil 3 are coaxially arranged with their axial end faces flush, and the inner diameter of the middle flat foil 3 is smaller than that of the top flat foil 5 .

[0038] As a preferred embodiment of the present invention, Figure 7As shown, there are three bottom-layer corrugated foils 2, each made of a 0.1mm thick high-temperature alloy foil. These three bottom-layer corrugated foils 2 form a circumferentially arranged corrugated arch, providing stiffness and damping for the lubricated surface. The bottom-layer corrugated foils 2 are uniformly welded to the middle-layer flat foil 3 along the circumference, with a spacing of 2mm between adjacent bottom-layer corrugated foils 2. Furthermore, the bottom-layer corrugated foils 2 have circumferentially extending slits distributed along the axial direction to adjust the structural stiffness of the radial bearing and prevent stress concentration.

[0039] As a preferred embodiment of the present invention, Figure 8 、 Figure 9 As shown, the middle flat foil 3 and the top flat foil 5 have essentially the same structure, with a slightly smaller inner diameter. The middle flat foil 3 provides a lubricating surface for the bearing. Using a double-layer flat foil structure allows the corrugated foil to be welded directly to the flat foil, facilitating bearing installation. This also improves the bearing's structural rigidity, increases frictional damping between the foils, and better absorbs rotor vibration energy, enhancing the stability of the rotor system.

[0040] Example 1

[0041] A double-layer flat foil radial bearing, such as Figure 2 、 Figure 3 and Figure 4 As shown, it includes a radial bearing seat 1, a bottom layer of corrugated foil 2, a middle layer of flat foil 3, a B-type pin 4, and a top layer of flat foil 5. The bottom layer of corrugated foil 2 is evenly welded to the middle layer of flat foil 3 along the circumference. To facilitate welding, the first corrugated arch of the bottom layer of corrugated foil 2, near the fixed end, is arranged outward, ensuring that the arch is in close contact with the bearing seat 1. The bent edges of the fixed ends of the middle layer of flat foil 3 and the top layer of flat foil 5 are joined together as fixed ends and extended into the bearing seat 1 to be welded to the flat side of the B-type pin 4. The fixed ends of the middle layer of flat foil 3 and the top layer of flat foil 5 are flush with the axial end face of the B-type pin, with a height difference of 0.5 mm from the axial end face of the bearing seat 1. The vertical length of the flat side of the B-type pin 4 is slightly shorter than the vertical length of the flat side of the locating slot in the bearing seat 1 to prevent the B-type pin 4 from extending out of the locating slot and interfering with the foil. The arc surface of the B-type pin 4 mates with the arc-shaped stop surface on the bearing seat 1. When the bearing is working, the b-shaped pin 4 is used for axial positioning and blocking, which can prevent radial vibration of the foil and make the bearing work more stably.

[0042] Example 2

[0043] This embodiment differs from Example 1 in that the middle flat foil 3 in this embodiment has slits extending circumferentially and distributed axially to adjust the structural stiffness of the radial foil bearing and prevent stress concentration. It should be noted that the slits should be positioned away from the corrugated foil welds.

[0044] Example 3

[0045] The difference between this embodiment and embodiment 1 is that, see Figure 11 、 Figure 12 In this embodiment, the thickness of the middle flat foil 3 varies along the circumferential direction. Based on the thickness, the middle flat foil 3 can be divided into a low-rigidity region and a high-rigidity region. The high-rigidity region has a thickness of 0.2 mm, and the low-rigidity region has a thickness of 0.1 mm.

[0046] High-stiffness areas correspond to high-load areas, with smaller lubrication gaps. Low-stiffness areas correspond to low-load areas, with larger lubrication gaps. By varying the thickness of the middle flat foil, the structural stiffness of the bearing is controlled, and the lubrication gap is adjusted accordingly.

[0047] In summary, the double-layer flat foil radial bearing proposed in this invention utilizes B-type pins in conjunction with the bearing seat for radial positioning and blocking, preventing radial vibration of the foil. This double-layer flat foil structure adjusts the structural stiffness of the radial foil bearing and prevents stress concentration. By varying the thickness of the middle flat foil layer to adjust the lubrication gap, it better absorbs rotor vibration energy and improves the stability of the rotor system. This eliminates the need for additional auxiliary devices, facilitating bearing installation, significantly increasing bearing reliability, and preventing failures.

[0048] The above descriptions are merely embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention description and drawings, or directly or indirectly applied to other related system fields, are also included in the scope of protection of the present invention.

Claims

1. A double-layer flat foil radial bearing, characterized by: It comprises a bearing seat (1), a B-type pin (4), a top flat foil (5), a middle flat foil (3) and a bottom corrugated foil (2); The bearing seat (1) is provided with a mounting groove, the B-type pin (4) is inserted into the mounting groove, and the mounting groove is provided with an arc-shaped limiting surface that matches the arc surface of the B-type pin; The main parts of the middle flat foil (3) and the top flat foil (5) are bent and located in the bearing seat (1); one end of the middle flat foil (3) and the top flat foil (5) are bent, and the formed bent edges are attached together as fixed ends and extend into the mounting groove of the bearing seat (1) together, and the fixed ends are fixedly connected to the plane side of the B-type pin (4); the bottom corrugated foil (2) is fixedly connected to the main part of the middle flat foil (3); The two end faces of the fixed ends of the middle flat foil (3) and the top flat foil (5) are respectively flush with the axial end faces of the corresponding B-shaped pins (4), and the end faces on both sides of the fixed ends of the middle flat foil (3) and the top flat foil (5) are lower than the axial end faces of the corresponding bearing seats (1); The thickness of the main body of the middle flat foil (3) in the circumferential direction is greater in the middle than in the two sides; the middle is a high-rigidity area, and the two sides are low-rigidity areas.

2. The double-layer flat foil radial bearing according to claim 1, characterized in that: The vertical length of the plane side of the B-type pin (4) is smaller than the vertical length of the plane side of the positioning groove of the bearing seat (1).

3. The double-layer flat foil radial bearing according to claim 1, characterized in that: The main parts of the top flat foil (5) and the middle flat foil (3) are coaxially arranged, with their axial end faces flush, and the inner diameter of the middle flat foil (3) is smaller than that of the top flat foil (5).

4. A double-layer flat foil radial bearing according to any one of claims 1 to 3, characterized in that: The thickness of the high-rigidity region in the middle-layer flat foil (3) is 0.2 mm, and the thickness of the low-rigidity region is 0.1 mm.

5. A double-layer flat foil radial bearing according to any one of claims 1 to 3, characterized in that: The middle layer flat foil (3) is provided with slits distributed in the axial direction and extending in the circumferential direction.

6. A double-layer flat foil radial bearing according to any one of claims 1 to 3, characterized in that: The number of the bottom corrugated foils (2) is three, and the three bottom corrugated foils (2) are evenly fixed to the middle flat foil (3) along the circumferential direction, and the spacing between two adjacent bottom corrugated foils (2) is 2 mm.

7. The double-layer flat foil radial bearing according to claim 5, characterized in that: The first corrugation arch of the bottom corrugated foil (2) close to the fixed end is arranged outwards and is closely attached to the bearing seat (1).

8. A double-layer flat foil radial bearing according to any one of claims 1 to 3, characterized in that: The bottom corrugated foil (2) is provided with slits distributed in the axial direction and extending in the circumferential direction.

9. A double-layer flat foil radial bearing according to any one of claims 1 to 3, characterized in that: The end faces on both sides of the fixed ends of the middle flat foil (3) and the top flat foil (5) are respectively 0.5 mm lower than the axial end faces of the corresponding bearing seats (1).

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