Radial wave foil, hydrodynamic radial bearing, electric machine, air compressor

Abstract

The present application provides a kind of radial wave foil, dynamic pressure gas float radial bearing, motor, air compressor, wherein the radial wave foil, including circumferential curling wave foil body, the wave foil body has first cutting gap extending along its circumference, second cutting gap, the first cutting gap and the second cutting gap cut the circumferential middle position of the wave foil body into first axial end area, middle area and second axial end area along its axial direction, in corresponding to the main bearing area of the wave foil body, the rigidity of the wave foil body in the first axial end area, second axial end area is less than the rigidity of the wave foil body in the middle area.According to the present application, the local deformation at the axial edge of the corresponding radial top foil can be increased, so that the corresponding bearing has greater eccentricity, and the load carrying capacity of the radial bearing is improved.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of foil bearing design, and particularly relates to a radial wave foil, a dynamic pressure gas floating radial bearing, a motor and an air compressor. BACKGROUND

[0002] The current elastic foil dynamic pressure gas floating radial bearing structure is shown in Figure 1 The overall structure in the motor is composed of a radial bearing seat 1, an elastic foil 2, a fixed unit 3 and a shaft neck 4. The elastic foil 2 is clamped in the fixed unit 3 through a bending part. Referring to Figure 2 and Figure 3 , the elastic foil 2 includes a bottom foil part 6 and a top foil part 7. As shown in Figure 3 , the design structure is an integrated mechanism of the top foil and the arch foil, and the entire radial bearing is assembled by six same structures. The free end of the arch foil is bent into a fixed part 5, and the other end is a free end 8 of the top foil. A radial mounting groove is arranged on the inner wall of the radial bearing seat 1, and the fixed part 5 is connected in the longitudinal mounting groove.

[0003] The main defects of the prior art structure are as follows:

[0004] 1. The consistency of bearing installation cannot be considered:

[0005] The radial bearing is composed of six structures as shown in Figure 3 . Firstly, there is a certain error in the preparation and bending process of the bearing. Since the height of the top foil depends on the height of the arch foil, in order to ensure the consistency of the entire radial bearing, the preparation height of each section with a wave-shaped unit is required to be very high. In actual working conditions, the consistency of the radial bearing preparation has a great influence on the operation of the motor, and therefore the design cannot guarantee the consistency of the radial bearing installation.

[0006] 2. The radial bearing has poor load bearing performance:

[0007] The radial bearing is composed of the top foil and the bottom foil. Each section has a fixed end and a free end, and this part has no support of the wave-shaped unit, which is the weakest position of the bearing load bearing performance. The radial bearing has six such structures, which leads to poor load bearing performance of the structure in the actual motor operation condition. The overall radial bottom foil will cause the top foil to produce a through-type deformation against the arch direction, causing the high-pressure gas in the center to leak to both ends, resulting in a decrease in the load bearing performance of the radial bearing.

[0008] In summary, the dynamic pressure gas floating radial bearing in the prior art has the problems of poor bearing preparation consistency and poor load bearing performance. SUMMARY

[0009] Therefore, the present application provides a radial wave foil, a dynamic pressure gas floating radial bearing, a motor and an air compressor, which can overcome the poor load bearing performance of the elastic foil dynamic pressure gas floating radial bearing in the prior art.

[0010] To solve the above problems, the present application provides a radial wave foil, comprising a circumferentially coiled wave foil body, the wave foil body having a first cutting gap and a second cutting gap extending along the circumferential direction thereof, the first cutting gap and the second cutting gap cutting a circumferential middle position of the wave foil body into a first axial end zone, a middle zone and a second axial end zone along the axial direction thereof, and the stiffness of the wave foil body in the first axial end zone and the second axial end zone is less than the stiffness of the wave foil body in the middle zone in a main load bearing area corresponding to the wave foil body.

[0011] In some embodiments, the first cutting gap extends in a convex shape in the circumferential direction of the wave foil body, the second cutting gap extends in a concave shape in the circumferential direction of the wave foil body, and the convex part of the first cutting gap and the concave part of the second cutting gap correspond in the axial direction of the wave foil body, so that the axial width of the wave foil body in the first axial end zone and the second axial end zone is less than the axial width of the wave foil body in the middle zone in the main load bearing area corresponding to the wave foil body.

[0012] In some embodiments, the pitch of the wave foil body in the first axial end zone and the second axial end zone is greater than the pitch of the wave foil body in the middle zone in the main load bearing area corresponding to the wave foil body.

[0013] In some embodiments, the pitch of the wave foil body in the first axial end zone and the second axial end zone is increased by 20% compared to the pitch of the wave foil body in the middle zone.

[0014] In some embodiments, the pitch of the wave foil body in the middle zone in the main load bearing area corresponding to the wave foil body is the same as the pitch of the wave foil body outside the main load bearing area.

[0015] In some embodiments, the wave foil body has a fixed end, and the arch peaks in the first axial end zone near one side of the fixed end are staggered with the arch peaks in the middle zone in the axial direction of the wave foil body, and / or the arch peaks in the second axial end zone near one side of the fixed end are staggered with the arch peaks in the middle zone.

[0016] In some embodiments, the circumferential length of the region where the arch peaks are staggered is 1 / 2 of the circumferential length of the wave foil body.

[0017] In some embodiments, the circumferential extension length of the first cutting gap is 3 / 4 of the circumferential length of the wave foil body; and / or, the circumferential extension length of the second cutting gap is 3 / 4 of the circumferential extension length of the wave foil body.

[0018] The present application also provides an elastic foil dynamic pressure gas-floated radial bearing, comprising a radial wave foil, which is the above-mentioned radial wave foil.

[0019] In some embodiments, the clamping groove constructed on the bearing seat is in its top position; and / or, the surface of the radial top foil has a high-temperature-resistant lubricating coating.

[0020] The present application also provides an electric machine, comprising the above-mentioned elastic foil dynamic pressure gas-floated radial bearing.

[0021] The present application also provides an air compressor, comprising the above-mentioned elastic foil dynamic pressure gas-floated radial bearing.

[0022] The radial wave foil, the dynamic pressure gas-floated radial bearing, the electric machine and the air compressor provided by the present application have the stiffness of the first shaft end region and the second shaft end region at both axial ends of the intermediate region reduced, which can increase the local deformation at the axial edges of the corresponding radial top foil, so that the corresponding bearing has a greater eccentricity, and the load-carrying performance of the radial bearing is improved. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 It is an axial structure schematic diagram of the elastic foil dynamic pressure gas-floated radial bearing in the prior art;

[0024] Figure 2 It is a structure schematic diagram of the integrated elastic radial foil in the prior art;

[0025] Figure 3 It is Figure 2 a flattened schematic diagram (i.e., the state before the elastic radial foil is curled);

[0026] Figure 4 It is Figure 1 a schematic diagram of the elastic foil dynamic pressure gas-floated radial bearing in the

[0027] Figure 5 It is an axial structure schematic diagram of the elastic foil dynamic pressure gas-floated radial bearing of the embodiment of the present application;

[0028] Figure 6 It is Figure 1 a flattened schematic diagram of the radial wave foil in the

[0029] Figure 7 It is Figure 5A local enlargement at I, showing the axially staggered arches.

[0030] Reference signs are indicated as:

[0031] 1. Bearing housing; 2. Elastic foil; 3. Fixed unit; 4. Journal; 5. Fixed part; 6. Bottom foil part; 7. Top foil part; 8. Free end; 9. Arch; 10. Wedge-shaped dynamic pressure gas film formed when the bearing rotates in the positive direction; 01. Bearing housing; 02. Radial wave foil; 03. Radial top foil; 101. First axial end area; 102. Middle area; 103. Second axial end area; 104. First cutting gap; 105. Second cutting gap. DETAILED DESCRIPTION

[0032] Reference is made in conjunction with Figures 1 to 7 It is shown that according to the embodiment of the present application, a radial wave foil is provided, comprising a circumferentially curled wave foil body, the wave foil body having a first cutting gap 104 and a second cutting gap 105 extending along the circumferential direction thereof, the first cutting gap 104 and the second cutting gap 105 cutting a circumferential middle position of the wave foil body into a first axial end area 101, a middle area 102 and a second axial end area 103 along the axial direction thereof, and the stiffness of the wave foil body of the first axial end area 101 and the second axial end area 103 is less than the stiffness of the wave foil body of the middle area 102 within the main load bearing area corresponding to the wave foil body. In this technical solution, the stiffness of the first axial end area 101 and the second axial end area 103 at both axial ends of the middle area 102 is reduced, which can increase the local deformation at the axial edge of the corresponding radial top foil 03, so that the corresponding bearing has a larger eccentricity, and the load bearing performance of the radial bearing is improved. In addition, one end of the radial wave foil is a fixed end and the other end is a free end, and the overall circumferential curling is close to a full circle, and there is no need to set multiple as in the prior art, that is, only one radial wave foil needs to be processed, which can be beneficial to ensure the consistency of processing and installation.

[0033] As a specific embodiment, the first cutting gap 104 extends in a convex shape (also can be called inverted U shape) along the circumferential direction of the wave foil body, the second cutting gap 105 extends in a concave shape (also can be called U shape) along the circumferential direction of the wave foil body, and the convex part of the first cutting gap 104 and the concave part of the second cutting gap 105 correspond in the axial direction of the wave foil body, so that within the main load bearing area corresponding to the wave foil body, the stiffness of the wave foil body of the first axial end area 101 (corresponding to the part within the dashed box 201 in the figure) and the second axial end area 103 (corresponding to the part within the dashed box 203 in the figure) is less than the stiffness of the wave foil body of the middle area 102. Figure 1 Figure 1 ​The axial width of the wave foil body in the portion within the dashed box 202 in FIG. 2 is less than the axial width of the wave foil body in the middle region 102, so that the middle width is greater than the two end edge axial widths, so that the middle stiffness of the radial bearing main load-carrying region is large and the two end stiffnesses are small. It needs to be specially pointed out that the first cutting gap 104 in the convex shape and the second cutting gap 105 in the concave shape make the wave foil body in the regions outside the first axial end region 101, the middle region 102 and the second axial end region 103 present wide→narrow→wide in the axial direction. The design of the cutting gap makes the radial top foil 03 recessed at the gap, reduces the axial width of the wave foil in each section, can increase the shaft center deformation amount of the bearing, and improves the stiffness and load-carrying performance of the radial bearing main load-carrying region.

[0034] As another specific embodiment, in the main load-carrying region of the wave foil body, the pitch of the wave foil body in the first axial end region 101 and the second axial end region 103 is greater than the pitch of the wave foil body in the middle region 102, and at this time, the parameters of the arch height and the flat section of the wave foil in the corresponding regions are unchanged, so as to facilitate the processing and manufacturing of the wave foil body. By adjusting and setting the pitches of the wave foils in different regions, the stiffness of the two end edges of the radial bearing is reduced, the minimum gas film thickness is increased, and the load-carrying capacity of the overall bearing can also be increased. Best of all, both different axial widths and different pitches in different regions can be set for the same wave foil body, so that the stiffness adjustment effects of the two are jointly exerted, and the load-carrying capacity of the bearing is improved. In a specific embodiment, the pitch of the wave foil body in the first axial end region 101 and the second axial end region 103 is increased by 20% than the pitch of the wave foil body in the middle region 102.

[0035] In some embodiments, the pitch of the wave foil body in the middle region 102 corresponding to the main load-carrying region of the wave foil body is the same as the pitch of the wave foil body outside the main load-carrying region, and at this time, the parameters of the arch height and the flat section of the wave foil in the corresponding regions are unchanged, so as to facilitate the processing and manufacturing of the wave foil body.

[0036] When the motor is running at high speed, a high-pressure lubrication gas film is formed in the gap between the gas dynamic pressure radial bearing and the rotating shaft. The gas pressure in the central region of the radial bearing is higher than that at both ends of the radial bearing. The overall radial wave foil arch structure will cause the top foil to produce a through deformation against the direction of the arch, causing the high pressure in the center to leak to both ends. This phenomenon is called end leakage. The aforementioned setting of the first cutting gap 104 and the second cutting gap 105 improves the stiffness of the radial bearing to be small in the middle and large at both ends. When the motor is running and a stable gas film is formed, the gas is not easy to leak when encountering impact vibration, improving the load capacity and stability of the gas dynamic pressure radial bearing, and to a certain extent, improving the end leakage phenomenon of the radial bearing and improving the bearing load capacity of the gas dynamic pressure radial bearing. In order to further improve the aforementioned end leakage phenomenon, in some embodiments, the wave foil body has a fixed end. In the axial direction of the wave foil body, the arch peaks in the first shaft end region 101 near the fixed end side are staggered with the arch peaks in the middle region 102, and / or the arch peaks in the second shaft end region 103 near the fixed end side are staggered with the arch peaks in the middle region 102. In some embodiments, the circumferential length of the staggered arch peak setting region is 1 / 2 of the circumferential length of the wave foil body. It should be noted that due to the different pitches of the first shaft end region 101, the second shaft end region 103 and the middle region 102, the arch peaks of these regions are staggered in the axial direction of the bearing, thereby effectively improving the end leakage phenomenon at both ends of the main bearing area of the bearing.

[0037] Generally, the circumferential extension length of the first cutting gap 104 is 3 / 4 of the circumferential length of the wave foil body; and / or the circumferential extension length of the second cutting gap 105 is 3 / 4 of the circumferential extension length of the wave foil body, to ensure that the optimization of the structure can improve the bearing load capacity for the main bearing area of the bearing.

[0038] According to the embodiment of the present application, there is also provided an elastic foil dynamic pressure gas-float radial bearing, comprising a radial wave foil 02, which is the radial wave foil as described above, and a radial top foil 03 arranged on the radial inner side of the radial wave foil 02, the radial top foil 03 being surrounded by a metal foil whole circle, and a clamping groove arranged on the top of the bearing seat 01, the radial wave foil being connected to the clamping groove through a fixed end, so as to avoid the phenomenon of insufficient support stiffness of the fixed end, and the flat section between the arch peaks of the radial wave foil being attached to the inner surface of the bearing seat 01, so as to ensure the consistency and feasibility of the bearing preparation; and / or, the surface of the radial top foil 03 having a high-temperature-resistant lubricating coating, which plays a lubricating and wear-resistant role in the start-stop stage of high-speed operation of the motor. During high-speed operation of the motor, the shaft rotates at high speed, and the eccentric motion of the shaft causes a wedge-shaped area to be formed between the rotor and the radial bearing gap, and after the gas enters the wedge-shaped area, a high-pressure lubricating gas film is formed, thereby providing the bearing-shaft system with a carrying capacity.

[0039] According to the embodiment of the present application, there is also provided a motor comprising the elastic foil dynamic pressure gas-float radial bearing as described above.

[0040] According to the embodiment of the present application, there is also provided an air compressor comprising the elastic foil dynamic pressure gas-float radial bearing as described above.

[0041] Those skilled in the art can easily understand that the above-mentioned advantageous modes can be freely combined and superimposed without conflict.

[0042] The above is only the preferred embodiment of the present application, and is not intended to limit the present application. 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 is only the preferred embodiment of the present application, and it should be pointed out that, for ordinary skilled in the art, without departing from the technical principles of the present application, a number of improvements and modifications can be made, and these improvements and modifications shall be regarded as the protection scope of the present application.

Claims

1. A radial wave foil, characterized in that, The radial wave foil (02) is the radial wave foil according to any one of claims 1 to 6.

2. The radial wave foil of claim 1, wherein, The clamping groove configured on the bearing seat (01) is in its top position; and / or the surface of the radial top foil (03) has a high-temperature-resistant lubricating coating.

3. The radial wave foil of claim 1, wherein, The elastic foil dynamic pressure gas floating radial bearing according to claim 7 or 8.

4. The radial wave foil of claim 3, wherein, The elastic foil dynamic pressure gas floating radial bearing according to claim 7 or 8.

5. The radial wave foil of claim 4, wherein, ​ 6. The radial wave foil of claim 1, wherein, ​ 7. An elastic foil hydrodynamic gas-film radial bearing comprising a radial wave foil (02), characterized in that, ​ 8. The elastic foil hydrodynamic gas-float radial bearing of claim 7, wherein, ​ 9. An electric machine characterized by ​ 10. An air compressor characterized by, ​

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