A homopolar gas-magnetic double-field dynamic pressure radial hybrid bearing

Abstract

The present invention discloses a homopolar gas-magnetic dual-field dynamic pressure radial hybrid bearing, which includes a magnetic bearing stator, a gas bearing stator, a stator fixing sleeve, a rotor and an electromagnetic coil with an iron core. A plurality of stator petals in the magnetic bearing stator are spliced ​​with the help of a stator fixing sleeve to form a hollow cylinder, each stator petal is provided with a through slot, and a centripetal boss is fixed on the inner surface of the stator petal, and the centripetal boss and the through slot form a through hole in which the iron core can be placed; the gas bearing stator is installed between the magnetic bearing stator and the rotor, and the outer surface of the gas bearing stator is alternately distributed with a plane and an arc surface, and the plane corresponds to the centripetal boss and the iron core formed inside the magnetic bearing stator; the inner surface of the gas bearing stator is provided with a plurality of grooves simulating the shape of hummingbird wings. In this way, the advantages of the homopolar magnetic bearing and the gas dynamic pressure bearing are combined, and the stiffness of the air film in the bearing air gap is significantly improved, so that the bearing has a greater load-bearing capacity and higher stability, and is easy to manufacture and assemble, and is suitable for popularization and use.

Description

Technical Field

[0001] The invention relates to the field of radial hybrid bearings, in particular to a homopolar gas-magnetic double-field dynamic pressure radial hybrid bearing. Background Art

[0002] A hydrodynamic gas bearing is a bearing that uses gas as a lubricating medium. When working, the rotor can completely float away from the stator. It has significant advantages such as high speed, cleanliness, smoothness, high temperature resistance, low temperature resistance, and long life. According to the shape of the bearing surface, hydrodynamic gas bearings can also be classified. Common types include platinum sheet type, slot type, cylindrical type, and stepped type. Among them, the slot type hydrodynamic gas bearing is a bearing with many slots machined on the surface of the gas bearing or the surface of the shaft. When the bearing rotor rotates at high speed, the viscous gas in the bearing air gap flows at high speed. Due to the flow conservation principle of gas motion, the gas pressure gradient between each slot in the air gap changes regularly, which significantly increases the gas pressure at the junction of the slot and enhances the bearing dynamic pressure effect, so that the slot type hydrodynamic gas bearing has a greater load-bearing capacity and higher stability than other types of hydrodynamic gas bearings. However, since the gas as a lubricating medium has low viscosity, the gas hydrodynamic bearing cannot form enough pressure in the bearing air gap to suspend the rotor during low-speed rotation or start-stop stage, resulting in dry friction between the bearing rotor and the stator during low speed and start-stop stages. Once the stator and rotor of a gas bearing come into contact and dry friction occurs during high-speed operation due to overload or other reasons, the gas bearing will completely lose its working ability in a very short time. In addition, the self-excited vortex instability and low load capacity of gas dynamic pressure bearings also limit their practicality.

[0003] Active magnetic bearings are active non-contact bearings that use electromagnetic field forces to suspend the bearing rotor in a specific space without mechanical friction or lubrication. The active magnetic bearing system includes a stator core, an electromagnetic coil, a power amplifier, a controller, a sensor, and a rotor. During operation, the sensor detects the rotor speed and position deviation, and the controller converts the rotor deviation displacement into a control signal, and the power amplifier converts the control signal into a control current. The control current causes the electromagnet to generate magnetic force so that the rotor maintains its suspended position unchanged. Active magnetic bearings can be divided into heteropolar and homopolar types according to the arrangement of magnetic poles. The heteropolar type is more common; general hybrid magnetic bearings are also mostly heteropolar, and homopolar types are relatively rare. The N poles and S poles of the commonly used heteropolar magnetic bearings are arranged in pairs in a cross direction along the circumferential direction.

[0004] When the rotor rotates once, the same position on the rotor surface will experience multiple magnetic field line reversals. Although the stator and rotor of the heteropolar magnetic bearing generally adopt a laminated structure, the surface eddy current and hysteresis losses are still large; and it is easy to make mistakes during assembly and welding, and the production cost is high.

[0005] There are many existing technologies for magnetic hybrid bearings, including a type that is a mixture of magnetic bearings and platinum gas bearings, and a type that is a mixture of magnetic bearings and slotted gas bearings. However, these types of hybrid bearings in the existing technologies all have their own limitations. The existing magnetic bearing and slotted gas hybrid bearing technology generally sets the slots on the outer surface of the rotor, and the magnetic bearing poles and the gas bearing are arranged in series in the axial direction. In order to ensure the performance of the magnetic bearing and the gas bearing, the axial size of the hybrid bearing must be increased, resulting in the overall structure of the bearing being not compact enough. The existing magnetic bearing and platinum gas hybrid bearing is a type of hybrid bearing with good comprehensive performance, which can ensure the overall compactness of the hybrid bearing, but the platinum gas bearing is weaker than the slotted gas bearing in terms of load-bearing capacity, stability and high-speed performance. Summary of the invention

[0006] The present invention provides a homopolar gas-magnetic dual-field dynamic pressure radial hybrid bearing, which solves the problems of the existing magnetic bearings with a non-compact structure, small bearing capacity and poor stability.

[0007] In order to solve the above technical problems, the technical solution provided by the present invention is: a homopolar gas-magnetic dual-field dynamic pressure radial hybrid bearing, comprising a stator fixing sleeve, a magnetic bearing stator, a gas bearing stator and a rotor which are coaxially arranged from the outside to the inside in sequence, the rotor is a hollow cylindrical type, the gas bearing stator sleeve is arranged outside the rotor, the structure of the gas bearing stator is a thin-walled cylindrical type, the outer surface of which is composed of four planes and four arc surfaces alternately, and the inner surface is provided with N grooves in the shape of hummingbird feathers;

[0008] The magnetic bearing stator comprises four identical stator lobes, and the four stator lobes are formed into a hollow cylinder with a closed outer surface through a stator fixing sleeve arranged on the end surface of the magnetic bearing stator. The edge of the circumferential surface of each stator lobe is provided with two axial through grooves, and the inner surface of the stator lobe is fixed with a rectangular centripetal boss, and the centripetal boss is located in the middle of the through groove. After the four stator lobes are combined, the centripetal boss and the through groove together form four rectangular through holes; a radial electromagnetic coil with an iron core is placed in each of the rectangular through holes, and the position of each plane on the outer surface of the gas bearing stator corresponds to a centripetal boss on the magnetic bearing stator and a group of radial electromagnetic coils with an iron core.

[0009] The bearing has a rotor, a gas bearing stator and a magnetic bearing stator coaxially mounted in sequence, and an electromagnetic coil with an iron core arranged between the gas bearing stator and the magnetic bearing stator is fixed by the plane on the outer circumferential surface of the gas bearing stator and the stator fixing sleeve and the centripetal boss on the magnetic bearing stator, thereby forming a gas-magnetic dual-field dynamic pressure radial hybrid bearing with a compact structure and more stable performance.

[0010] The structure of the stator petals is easy to manufacture and simple to assemble; the centripetal boss is fixed to the inner circumferential surface and is located in the middle of the through groove, so that after the stator petals are assembled, the through grooves on both sides can form a through hole with the internal centripetal boss for installing the coil with the iron core; and the stator composed of four complete block-shaped stator petals is safer and more stable to use, and is also more convenient to repair and replace.

[0011] N gas grooves are opened on the inner surface of the gas bearing stator to replace the grooves on the laminated rotor, so that the resistance and loss of the rotor itself are greatly reduced when it rotates. At the same time, the presence of the grooves ensures the change of gas flow speed and density between the rotor and the gas bearing stator, thereby improving the stiffness of the gas film in the gap.

[0012] The iron core is in the shape of a semi-enclosed rectangular frame, with radial electromagnetic coils installed on two short sides, and the length of the centripetal boss is adapted to the spacing between the radial electromagnetic coils at both ends.

[0013] The plane width of the outer surface of the gas bearing stator is adapted to the width of the centripetal boss and the width of the radial electromagnetic coil; the center angle corresponding to the plane is less than or equal to the center angle corresponding to the arc surface. The centripetal boss in the magnetic bearing stator is matched with the shape of the semi-enclosed rectangular frame iron core, so that the internal structure of the bearing is compactly arranged while fixing the iron core with the radial electromagnetic coil. The width and height of the radial electromagnetic coil are adapted to the width and height of the centripetal boss, and the radial electromagnetic coil is wound on the two short sides of the iron core. The width of the radial electromagnetic coil is slightly smaller than the width of the centripetal boss, which is convenient for the subsequent installation of the fixing device to fix the radial electromagnetic coil to the centripetal boss; in this way, the sizes of the three parts are matched. On the one hand, the width of the plane ensures that the centripetal boss and the radial electromagnetic coil with the iron core can be accommodated. On the other hand, it is easy to unify the size standards of each part during manufacturing, and the parts are nested, which significantly saves space inside the bearing.

[0014] The plane on the gas bearing stator is used to place the external iron core, which is more stable than when placed on a circular surface. Moreover, compared with directly stacking and placing the plane on the circular surface, the situation where the plane is tangent to the circular surface can save some space and improve space utilization. At the same time, the range of the plane is not excessively enlarged, ensuring that the circular surface occupies the majority and matching the shape of the external magnetic bearing stator as much as possible, leaving enough space for other components.

[0015] The N grooves on the inner surface of the gas bearing stator are closely arranged, the center line of each groove is inclined relative to the axis direction of the gas bearing stator, the head and tail ends of adjacent grooves are arranged in succession to form a spiral track, and the axis of the spiral track coincides with the axis of the gas bearing stator. There is a certain distance between the head and tail ends of adjacent grooves, and the center line of the groove coincides with the spiral line.

[0016] The outer edge of a single groove is in the shape of the outer contour of a hummingbird feather, and the internal structure is wedge-shaped. The groove includes two arc edges and two side edges. The arc radii of the two arc edges are different, and they are divided into a large radius arc edge and a small radius arc edge. The concave depth of the small radius arc edge is greater than that of the large radius arc edge; the surface of the connection between the two arc edges and the two side edges is smooth. Specifically, the small arc radius and the large arc radius are arranged relative to each other, and the middle is connected by the first side edge and the second side edge. N grooves are staggered and closely arranged on the inner surface of the gas bearing stator. When the internal rotor rotates, a relatively stable air film can be formed between the rotor and the entire gas bearing stator. The wedge shape and the spirally distributed structural design of the N grooves allow the gas to enter the rotor and the gas bearing stator more smoothly after the rotor rotates; and the wedge shape of the groove itself and the platform between the grooves further increase the internal gas pressure, further improve the air film stiffness between the gas bearing stator and the rotor, and thus enhance the bearing capacity of the bearing.

[0017] In addition, designing the groove based on the outer contour of a hummingbird's feathers can take advantage of the bird's unique flight characteristics and ensure the stability of the gas flow; the depression of the small-radius arc edge is deeper than the depression of the large-radius arc edge, which increases the amount of change in the gas flow process. The rounded corners of each edge make it easy for the gas to enter and exit, ensuring the smooth realization of the groove function.

[0018] The stator fixing sleeve includes a first fixing sleeve and a second fixing sleeve of the same structure, which are respectively arranged at the two ends of the magnetic bearing stator; the first fixing sleeve and the second fixing sleeve include an end face fixing ring, an outer circle fixing sheet and an inner circle fixing sheet, the outer circle fixing sheet and the inner circle fixing sheet are vertically fixed on the end face fixing ring, and the inner circle fixing sheet inside the end face fixing ring is provided with a first radial boss fixing sheet and a second radial boss fixing sheet at both ends. Two fixing sleeves are respectively arranged at both ends, which, on the one hand, effectively fixes the magnetic bearing stator and the internal iron core and coil, and on the other hand, such a fixing sleeve has a simple structure, is easy to manufacture, and is convenient to install and disassemble.

[0019] The inner diameter of the outer circle fixing plate and the outer diameter of the inner circle fixing plate are respectively equal to the outer diameter and inner diameter of the magnetic bearing stator; the spacing between the first boss fixing plate on an inner circle fixing plate and the second boss fixing plate of the adjacent inner circle fixing plate is equal to the width of the centripetal boss, and the axial length of the radial electromagnetic coil is less than the axial length of the first boss fixing plate. In the actual winding process, the width of the radial electromagnetic coil is slightly smaller than the centripetal boss, and the boss fixing plate that is longer than the axial length of the radial electromagnetic coil will extend to the centripetal boss in the middle of the magnetic bearing stator, which can effectively ensure the position of the radial electromagnetic coil between the two boss fixing plates; because the axial lengths of the first boss fixing plate and the second boss fixing plate are the same, the first boss fixing plate and the second boss fixing plate at both ends respectively fix the two radial electromagnetic coils.

[0020] The inner surface of the gas bearing stator is provided with N rows of groove groups arranged in a straight line, and the center lines of the N grooves in each row of groove groups are parallel to each other and are distributed at equal intervals. The center line of each row can be parallel to or intersect the axis of the gas bearing stator, so that multiple grooves can still be provided on the inner surface of the gas bearing stator and arranged closely, and the manufacturing process is relatively simple, the cost is low, and it can be put into use on a larger scale.

[0021] The center plane of the iron core coincides with the center line of the bearing. In this way, the magnetic field generated by the iron core and the electromagnetic coil can be evenly distributed in the bearing, and the direction of the magnetic field is more regular, so that the stability of the bearing is guaranteed.

[0022] The gas bearing stator is made of non-ferromagnetic material, which will not interfere with the magnetic field distribution of the magnetic bearing stator, thereby avoiding affecting the suspension performance of the magnetic bearing.

[0023] This bearing combines the characteristics of a hydrodynamic gas bearing and an electromagnetic suspension bearing. On the one hand, the rotor, gas bearing stator and magnetic bearing stator are coaxially assembled in sequence. The electromagnetic bearing provides the main load capacity when the bearing is started and stopped and operates at low speed, and the hydrodynamic gas bearing provides the main load capacity when the bearing operates at high speed. At the same time, when the rotor becomes unstable due to overload or other reasons during the high-speed operation of the bearing and the displacement exceeds the preset range, the magnetic bearing stator intervenes to add controllable damping to the bearing rotor. On the other hand, in the stator part of the magnetic bearing, each pair of magnetic poles is distributed axially, that is, there is only N pole or S pole along the circumferential direction, the magnetic lines of force are parallel to the rotor axis, and the direction of the magnetic field is from the same end of the rotor to the other end. Its loss will be greatly reduced compared with other types of magnetic bearings.

[0024] Compared with the prior art, the essential features of the present invention are:

[0025] (1) Small hysteresis loss and reduced power loss. The use of a homopolar magnetic bearing structure does not require the bearing rotor to adopt a laminated structure to make the hysteresis loss of the magnetic bearing very small. At the same time, not using a laminated rotor structure is also conducive to ensuring the excellent performance of the hydrodynamic gas bearing;

[0026] (2) Compact structure and small size. The present invention adopts the form of setting grooves on the inner surface of the gas bearing stator, and it is unnecessary to set the grooves on the rotor surface, thereby ensuring that the rotor surface structure is uniform and smooth, and the magnetic bearing suspension performance is not affected by the rotor surface structure; at the same time, because the gas bearing stator adopts non-ferromagnetic materials, the magnetic field of the magnetic bearing stator is not affected when passing through the gas bearing stator. This structural arrangement allows the magnetic poles of the magnetic bearing stator and the gas bearing stator to be arranged in parallel in the axial direction, making full use of the axial space of the bearing, making the bearing more compact in structure and smaller in size, while exerting excellent performance;

[0027] (3) High rotation accuracy and large load-bearing capacity. The gas bearing stator is equipped with multiple grooves in the shape of hummingbird wings to simulate the special physiological structure of hummingbird wings. The gas passes through the throttling and blocking effect of the wedge-shaped mechanism inside the groove, which changes the gas flow rate and gas density at the edge of the groove, increases the pressure of the dynamic pressure gas film in the bearing air gap, and improves the suspension support accuracy of the bearing;

[0028] (4) Long life and good stability. When the rotor deviates from the preset position range during the low-speed start-stop stage of the bearing and high-speed operation, the magnetic bearing stator intervenes to ensure that the bearing does not have dry friction, thereby improving the stability of the bearing and increasing the life of the bearing. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

[0030] Figure 1 It is the overall assembly structure of the homopolar gas-magnetic double-field dynamic pressure radial hybrid bearing of the present invention.

[0031] Figure 2 It is a structural explosion diagram of the homopolar gas-magnetic dual-field dynamic pressure radial hybrid bearing of the present invention.

[0032] Figure 3 It is a schematic diagram of the structure of the stator fixing sleeve in the present invention.

[0033] Figure 4 It is a schematic diagram of the half-section structure of the gas bearing stator in the present invention.

[0034] Figure 5 It is a schematic diagram of the magnetic bearing stator of the homopolar gas-magnetic dual-field dynamic pressure radial hybrid bearing of the present invention.

[0035] Figure 6 It is a schematic diagram of the magnetic flux distribution of the magnetic bearing of the homopolar gas-magnetic dual-field dynamic pressure radial hybrid bearing of the present invention.

[0036] Figure 7 It is a schematic diagram of the structure of a single groove in the present invention.

[0037] In the figure: 1. first stator fixing sleeve, 2. rotor, 3. gas bearing stator, 4. radial electromagnetic coil, 5. iron core, 6. magnetic bearing stator, 7. second stator fixing sleeve, 8. outer circle fixing plate, 9. first boss fixing plate, 10. second boss fixing plate, 11. inner circle fixing plate, 12. groove, 13. fixing platform, 14. stator petal, 15. through groove, 16. centripetal boss, 1201. large radius arc edge, 1202. small radius arc edge, 1203. first side edge, 1204. second side edge. DETAILED DESCRIPTION

[0038] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only 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.

[0039] In the description of the present invention, it should be noted that, if the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. appear, the orientation or position relationship indicated is based on the orientation or position relationship shown in the drawings, which is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, if the terms "first", "second", "third" appear, they are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0040] In the description of the invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0041] Example 1

[0042] As shown in the accompanying drawings, a homopolar gas-magnetic dual-field dynamic pressure radial hybrid bearing includes a stator fixing sleeve, a magnetic bearing stator 6, a gas bearing stator 3 and a rotor 2 which are coaxial and arranged in sequence from the outside to the inside. The rotor is a hollow cylindrical type, and the gas bearing stator 3 is sleeved on the outside of the rotor 2. The overall structure of the gas bearing stator 3 is a thin-walled cylindrical type, and its outer surface is composed of four planes and four arc surfaces alternatingly, and N grooves 12 in the shape of hummingbird feathers are opened on the inner surface. Specifically, the outer surface of the rotor 2 is a smooth and complete circular surface; the outer edge of a single groove 12 on the gas bearing stator 3 is in the shape of the outer contour of a hummingbird feather, and the internal structure is wedge-shaped, and the groove 12 includes two arcuate edges and two side edges: the two side edges are straight lines and connect the two arcuate edges together; the arc radii of the two arcuate edges are different, and they are divided into a large-radius arcuate edge 1201 and a small-radius arcuate edge 1202, and the concave depth of the small-radius arcuate edge 1202 is greater than that of the large-radius arcuate edge 1201; the surface of the connection between the two arcuate edges and the two side edges is smooth.

[0043] The magnetic bearing stator 6 includes four identical stator lobes 14, and the four stator lobes 14 form a hollow cylinder with a closed outer surface through a stator fixing sleeve arranged on the end face of the magnetic bearing stator 6. Two axial through grooves 15 are opened on the edge of the circumferential surface of each stator lobe 14, and a rectangular centripetal boss 16 is fixed on the inner surface of the stator lobe 14. The centripetal boss 16 is located in the middle of the through groove 15, and a centripetal boss 16 is fixed on the inner side of one of the through grooves 15 of each stator lobe.

[0044] When the four stator lobes 14 are combined, a through slot 15 with a centripetal boss 16 on one stator lobe 14 is combined with a through slot 15 without a centripetal boss 16 on another stator lobe 14, and finally the centripetal boss 16 and the through slot 15 together form four rectangular through holes; a radial electromagnetic coil 4 with an iron core 5 is placed in each rectangular through hole, and the position of each plane on the outer surface of the gas bearing stator 3 corresponds to a centripetal boss 16 on the magnetic bearing stator 6 and a group of radial electromagnetic coils 4 with an iron core 5.

[0045] The iron core 5 is in the shape of a semi-enclosed rectangular frame, with radial electromagnetic coils 4 mounted on two short sides, and the length of the centripetal boss 16 is adapted to the spacing between the radial electromagnetic coils 4 at both ends. During installation, the radial electromagnetic coils 4 with the iron core 5 can be exactly matched with the centripetal boss 16, ensuring that all components are stably installed and assembled into the magnetic bearing stator 6.

[0046] The plane width of the outer surface of the gas bearing stator 3 is adapted to the width of the centripetal boss 16 and the width of the radial electromagnetic coil 4, so the plane is a fixed platform 13, which is used to fix the radial electromagnetic coil 4 with the iron core 5 and enable the centripetal boss 16 to be placed stably; the central angle corresponding to the fixed platform 13 is less than or equal to the central angle corresponding to the arc surface, which ensures that the components are fixed while cooperating with the shape of the gap between the external magnetic bearing stator 6, which is more conducive to the arrangement of other components.

[0047] Example 2

[0048] A homopolar gas-magnetic dual-field dynamic pressure radial hybrid bearing comprises a stator fixing sleeve, a magnetic bearing stator 6, a gas bearing stator 3 and a rotor 2 which are coaxially arranged from the outside to the inside. The rotor 2 is a hollow cylindrical type. The gas bearing stator 3 is sleeved on the outside of the rotor 2. The overall structure of the gas bearing stator 3 is a thin-walled cylindrical type. The outer surface of the gas bearing stator 3 is composed of four planes and four arc surfaces alternately. The inner surface is provided with N grooves 12 in the shape of hummingbird feathers.

[0049] The magnetic bearing stator 6 comprises four identical stator segments 14, and the four stator segments 14 form a hollow cylinder with a closed outer surface through a stator fixing sleeve arranged on the end surface of the magnetic bearing stator 6. The edge of the circumferential surface of each stator segment 14 is provided with two axial through grooves 15. The inner surface of the stator segment 14 is fixed with a rectangular parallelepiped centripetal boss 16, and the centripetal boss 16 is located in the middle of the through groove 15. After the four stator segments 14 are combined, the centripetal boss 16 and the through groove 15 together form four rectangular through holes; a radial electromagnetic coil 4 with an iron core 5 is placed in each rectangular through hole, and the position of each plane on the outer surface of the gas bearing stator 3 corresponds to a centripetal boss 16 on the magnetic bearing stator 6 and a group of radial electromagnetic coils 4 with an iron core 5. The iron core 5 is in the shape of a semi-closed rectangular frame, and radial electromagnetic coils 4 are installed on the two short sides. The length of the centripetal boss 16 is adapted to the spacing between the radial electromagnetic coils 4 at both ends.

[0050] The plane width of the outer surface of the gas bearing stator 3 is adapted to the width of the centripetal boss 16 and the width of the radial electromagnetic coil 4; the center angle corresponding to the plane is less than or equal to the center angle corresponding to the arc surface.

[0051] The N grooves 12 on the inner surface of the gas bearing stator 3 are closely arranged, and the N grooves are distributed in a spiral shape: the center line of each groove is inclined, and the head and tail ends of adjacent grooves are arranged in succession to form a spiral track, and a certain distance is left between the head and tail ends of adjacent grooves, and the axis of the spiral track coincides with the axis of the gas bearing stator 3. The outer edge of a single groove 12 is in the shape of the outer contour of a hummingbird feather, and the internal structure is wedge-shaped. The groove 12 includes two arc-shaped edges and two side edges, and the two side edges are curved and connect the two arc-shaped edges together, such as Figure 7 , divided into a first side edge 1203 and a second side edge 1204; the arc radii of the two arc edges are different, and are divided into a large-radius arc edge 1201 and a small-radius arc edge 1202, and the concave depth of the small-radius arc edge 1202 is greater than that of the large-radius arc edge 1201; the connection between the two arc edges and the two side edges has a smooth surface.

[0052] Example 3

[0053] Furthermore, if Figure 4 As shown, in this type of homopolar gas-magnetic dual-field dynamic pressure radial hybrid bearing, the inner surface of the gas bearing stator 3 is provided with a plurality of rows of groove groups arranged in a linear manner, the center line of each row is parallel to the axis of the gas bearing stator 3 in the plane, the plurality of grooves 12 in each row are distributed at equal intervals, and the plurality of grooves 12 of adjacent groove groups are staggered and closely arranged.

[0054] Example 4

[0055] A homopolar gas-magnetic double-field dynamic pressure radial hybrid bearing comprises a stator fixing sleeve, a magnetic bearing stator 6, a gas bearing stator 3 and a rotor 2 which are coaxial and arranged in sequence from outside to inside. The rotor 2 is a hollow cylindrical type. The gas bearing stator 3 is sleeved on the outside of the rotor. The overall structure of the gas bearing stator 3 is a thin-walled cylindrical type. Its outer surface is composed of four planes and four arc surfaces alternately, wherein each plane is a fixed platform 13. N grooves 12 in the shape of hummingbird feathers are closely arranged on the inner surface. The outer edge of a single groove 12 is in the shape of the outer contour of a hummingbird feather, and the internal structure is wedge-shaped. The groove 12 includes two arc-shaped edges and two side edges, one side edge is a straight line, and the other side edge is a curve, which connects the two arc-shaped edges together; the arc radii of the two arc-shaped edges are different, and they are divided into a large radius arc-shaped edge 1201 and a small radius arc-shaped edge 1202, and the concave depth of the small radius arc-shaped edge 1202 is greater than that of the large radius arc-shaped edge 1201; the surface of the connection between the two arc-shaped edges and the two side edges is smooth.

[0056] The magnetic bearing stator 6 includes four identical stator lobes 14, and the four stator lobes 14 form a hollow cylinder with a closed outer surface through a stator fixing sleeve arranged on the end face of the magnetic bearing stator 6. Two axial through grooves 15 are opened on the edge of the circumferential surface of each stator lobe 14, and a boss block is fixed on the inner side of each through groove 15, and every two boss blocks form a centripetal boss 16; after the four stator lobes 14 are combined, the inner surface of the stator lobe 14 forms a rectangular centripetal boss 16, and the centripetal boss 16 is located in the middle of the through groove 15. The centripetal boss 16 and the through groove 15 together form four rectangular through holes.

[0057] A radial electromagnetic coil 4 with an iron core 5 is placed in each rectangular through hole. The iron core 5 is in the shape of a semi-enclosed rectangular frame. The radial electromagnetic coils 4 are installed on the two short sides. The length of the centripetal boss 16 is adapted to the spacing between the radial electromagnetic coils 4 at both ends, so that the radial electromagnetic coils 4 at both ends can just be stuck at both ends of the centripetal boss 16. The center plane of the iron core 5 coincides with the center line of the bearing. At the same time, due to problems such as coil winding, the width of the formed radial electromagnetic coil 4 is slightly smaller than the width of the centripetal boss 16.

[0058] The position of each fixed platform 13 corresponds to a centripetal boss 16 on a magnetic bearing stator 6 and a group of radial electromagnetic coils 4 with an iron core 5. The width of the fixed platform 13 is adapted to the width of the centripetal boss 16 and the width of the radial electromagnetic coil 4, that is, it can just accommodate the centripetal boss 16 and two radial electromagnetic coils 4, ensuring that both are stably placed in the bearing; the central angle corresponding to the fixed platform 13 is less than or equal to the central angle corresponding to the arc surface.

[0059] The stator fixing sleeve includes two first fixing sleeves 1 and second fixing sleeves 7 with the same structure, which are respectively arranged at the two ends of the magnetic bearing stator 6; the first fixing sleeve 1 and the second fixing sleeve 7 include an end face fixing ring, an outer circle fixing plate 8 and an inner circle fixing plate 11, and the outer circle fixing plate 8 and the inner circle fixing plate 11 are vertically fixed on the end face fixing ring. The two ends of the inner circle fixing plate 11 on the inner side of the end face fixing ring are provided with radial first boss fixing plates 9 and second boss fixing plates 10.

[0060] The inner surface diameter of the outer circle fixing plate 8 and the outer surface diameter of the inner circle fixing plate 11 are respectively equal to the outer circumferential surface diameter and the inner circumferential surface diameter of the magnetic bearing stator 6; the spacing between the first boss fixing plate 9 on an inner circle fixing plate 11 and the second boss fixing plate 10 of the adjacent inner circle fixing plate 11 is equal to the width of the centripetal boss 16, and the axial length of the radial electromagnetic coil 4 is smaller than the axial length of the first boss fixing plate 9 or the second boss fixing plate 10, so that the first boss fixing plate 9 and the second boss fixing plate 10 can extend from both ends to the middle centripetal boss 16, thereby ensuring that the positions of the radial electromagnetic coils 4 at both ends are fixed.

[0061] The gas bearing stator 3 is made of non-ferromagnetic material to ensure that the magnetic field of the magnetic bearing is not affected when passing through the gas bearing stator 3 .

[0062] like Figure 4 The gas bearing stator 3 is a thin-walled cylindrical structure, and four fixed platforms 13 are arranged on its outer surface. The four platform surfaces are relatively parallel and adjacent to each other and vertical. The four fixed platforms 13 cooperate with the four centripetal bosses 16 of the magnetic bearing stator 6 to fix the gas bearing stator 3. The inner surface of the gas bearing stator 3 is provided with spirally distributed hummingbird feather-shaped grooves 12. The outer contour of the grooves 12 simulates the outer contour of the hummingbird wings. The spiral angle simulates the relative angle between the wings of the hummingbird and the plane facing the hummingbird space when the hummingbird is hovering in the air. Each groove 12 is also a wedge-shaped space.

[0063] When the gas passes through the groove 12, due to the throttling and blocking effect of the groove 12, the speed and density of the gas at the edge of the groove 12 change, so that the gas pressure at the junction of the groove 12 and the platform is significantly increased, so that the dynamic pressure air film stiffness of the bearing support gap and the bearing load-bearing capacity are improved.

[0064] When the bearing is working, the air film for support consists of two parts. One part is the aerodynamic pressure air film generated by the wedge-shaped space between the entire gas bearing stator 3 and the eccentrically rotating rotor 2. The other part is the aerodynamic pressure air film generated by the wedge-shaped space formed by the groove 12 made based on the outer contour of the hummingbird wing feathers, and due to the action of the viscous compressor formed by the spiral arrangement of N grooves 12, the dynamic pressure air film generated by the increase in air film pressure caused by the change in gas velocity and density inside the bearing. The dynamic pressure air films at these two places are superimposed, and the air film stiffness in the gap and the load-carrying capacity of the bearing are significantly improved compared to before, so that the rotor 2 of the bearing can work stably in suspension, with high stability and large load-carrying capacity.

[0065] As Figure 6 , it can be seen that in this bearing, the direction of the magnetic field lines passing through the rotor 2 is parallel to the axis direction of the bearing.

[0066] In actual implementation of the present invention, a complete set of electromagnetic bearing control systems should be equipped. The control system also includes a controller, a power amplifier, a sensor for detecting the rotor speed, a sensor for detecting the rotor displacement, and a vibration analyzer for detecting the vibration condition of the center position of the rotor 2. When the magnetic bearing stator is working, the rotor speed and displacement are detected by the sensors, the controller converts the rotor speed and displacement into control signals, and then the power amplifier converts the control signals into control currents. The control currents make the electromagnets generate magnetic forces to control the rotor 2 to work within the suspension range.

[0067] The magnetic bearing stator starts to work under three working conditions.

[0068] ① When the speed sensor detects that the rotor 2 speed V, 0 < V < V1 (V1 is 110% of the gas bearing rotor suspension speed value), the magnetic bearing stator starts. When the sensor detects that the rotor 2 speed V = 0 or V > V1, the magnetic bearing stator stops.

[0069] ② When the speed sensor detects that the rotor 2 speed V2 < V < V3, the magnetic bearing stator starts. When V > V3, the magnetic bearing stator stops (V2 and V3 are 90% and 110% of the critical speed values when the gas bearing undergoes self-excited whirl respectively).

[0070] ③ When the displacement sensor detects that the displacement of the center position of the rotor 2 exceeds the predetermined amplitude range, the magnetic bearing stator starts.

[0071] In summary, the present invention provides a homopolar gas-magnetic dual-field dynamic pressure radial hybrid bearing with hummingbird wing-shaped grooves, in which the magnetic bearing stator 6 bears the main load for the rotor 2 when the bearing is working at low speed and start-stop, and the gas bearing stator 3 bears the main load for the rotor 2 when working at high speed; at the same time, when the bearing is working at high speed and there is an instability condition caused by overload or half-speed vortex of the gas bearing stator, the magnetic bearing stator 6 can provide controllable damping for the rotor 2. The bearing is suitable for a variety of high-speed and low-speed working conditions, can be started and stopped frequently, and has the characteristics of large load, high stability and compact structure.

[0072] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A homopolar gas-magnetic dual-field dynamic pressure radial hybrid bearing, characterized in that: It includes a stator fixing sleeve, a magnetic bearing stator, a gas bearing stator and a rotor which are coaxially arranged in sequence from outside to inside. The rotor is a hollow cylindrical shape, and the gas bearing stator is sleeved outside the rotor. The gas bearing stator is a thin-walled cylindrical structure, the outer surface of which is composed of four planes and four arc surfaces alternately, and the inner surface is provided with N grooves in the shape of hummingbird feathers; The magnetic bearing stator comprises four identical stator lobes, and the four stator lobes are formed into a hollow cylinder with a closed outer surface through a stator fixing sleeve arranged on the end surface of the magnetic bearing stator. The edge of the circumferential surface of each stator lobe is provided with two axial through grooves, and the inner surface of the stator lobe is fixed with a rectangular parallelepiped centripetal boss, and the centripetal boss is located in the middle of the through groove. After the four stator lobes are combined, the centripetal boss and the through groove together form four rectangular through holes; a radial electromagnetic coil with an iron core is placed in each of the rectangular through holes. The position of each plane on the outer surface of the gas bearing stator corresponds to a centripetal boss on the magnetic bearing stator and a group of radial electromagnetic coils with iron cores.

2. The homopolar gas-magnetic dual-field dynamic pressure radial hybrid bearing according to claim 1 is characterized in that: The iron core is in the shape of a semi-enclosed rectangular frame, with radial electromagnetic coils mounted on two short sides, and the length of the centripetal boss is adapted to the spacing between the radial electromagnetic coils at both ends.

3. The homopolar gas-magnetic dual-field dynamic pressure radial hybrid bearing according to claim 1 is characterized in that: The plane width of the outer surface of the gas bearing stator is adapted to the width of the centripetal boss and the width of the radial electromagnetic coil; the center angle corresponding to the plane is less than or equal to the center angle corresponding to the arc surface.

4. The homopolar gas-magnetic dual-field dynamic pressure radial hybrid bearing according to claim 1 is characterized in that: The N grooves on the inner surface of the gas bearing stator are closely arranged, the center line of each groove is inclined relative to the axial direction of the gas bearing stator, the head and tail ends of adjacent grooves are arranged in succession to form a spiral track, and the axis of the spiral track coincides with the axis of the gas bearing stator.

5. The homopolar gas-magnetic dual-field dynamic pressure radial hybrid bearing according to claim 1 is characterized in that: The outer edge of a single groove is in the shape of the outer contour of a hummingbird feather, and the internal structure is wedge-shaped. The groove includes two arcuate edges and two side edges. The arc radii of the two arcuate edges are different, and they are divided into a large-radius arcuate edge and a small-radius arcuate edge. The concave depth of the small-radius arcuate edge is greater than that of the large-radius arcuate edge; the surface of the connection between the two arcuate edges and the two side edges is smooth.

6. The homopolar gas-magnetic dual-field dynamic pressure radial hybrid bearing according to claim 1 is characterized in that: The stator fixing sleeve includes a first fixing sleeve and a second fixing sleeve with the same structure, which are respectively arranged at the two ends of the magnetic bearing stator; the first fixing sleeve and the second fixing sleeve include an end face fixing ring, an outer circle fixing plate and an inner circle fixing plate, the outer circle fixing plate and the inner circle fixing plate are vertically fixed on the end face fixing ring, and radial first boss fixing plates and second boss fixing plates are provided at both ends of the inner circle fixing plate on the inner side of the end face fixing ring.

7. The homopolar gas-magnetic dual-field dynamic pressure radial hybrid bearing according to claim 6 is characterized in that: The inner circle surface diameter of the outer circle fixing plate and the outer circle surface diameter of the inner circle fixing plate are respectively equal to the outer circumferential surface diameter and the inner circumferential surface diameter of the magnetic bearing stator; the spacing between the first boss fixing plate on an inner circle fixing plate and the second boss fixing plate of the adjacent inner circle fixing plate is equal to the width of the centripetal boss, and the axial length of the radial electromagnetic coil is smaller than the axial length of the first boss fixing plate.

8. The homopolar gas-magnetic dual-field dynamic pressure radial hybrid bearing according to claim 1 is characterized in that: The center plane of the core coincides with the center line of the bearing.

9. The homopolar gas-magnetic dual-field dynamic pressure radial hybrid bearing according to claim 1, characterized in that: The inner surface of the gas bearing stator is provided with N rows of groove groups arranged in a linear manner, and the center lines of the N grooves in each row of the groove group are parallel to each other and are distributed at equal intervals.

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