Radial protection angular contact ball bearing pack for magnetic suspension main shaft

Abstract

A radial protection angular contact ball bearing pack for a magnetic suspension spindle is formed by assembling N sets of angular contact ball bearings of the same model number, the N sets of angular contact ball bearings are larger than or equal to 2, each angular contact ball bearing is of a non-full complement rolling body retainer-free structure and comprises a bearing outer ring, a bearing inner ring and rolling bodies, the bearing outer rings are arranged outside the bearing inner rings in a sleeving mode, and the rolling bodies are arranged on the bearing inner rings in a sleeving mode. Raceways are formed on the surfaces of the opposite sides of the bearing outer rings and the bearing inner rings, the rolling bodies are arranged between the raceways of the bearing outer rings and the raceways of the bearing inner rings, molybdenum disulfide coatings or polytetrafluoroethylene layers are arranged on the raceways of the bearing outer rings and the raceways of the bearing inner rings, annular grooves are formed in the inner diameters of the bearing inner rings, and the rolling bodies are arranged in the annular grooves. An elastic damper providing radial elastic damping supporting is installed in the annular groove, and the inner surface of the elastic damper protrudes out of the inner diameter surface of the bearing inner ring. The protection bearing is prevented from being vibrated and impacted, the working rotating speed of the protection bearing is increased, sintering adhesion of the magnetic suspension spindle and the bearing is effectively prevented, and therefore the magnetic suspension spindle is protected.

Description

Technical Field

[0001] The utility model relates to the technical field of bearings, in particular to a radial protection angular contact ball bearing group for a magnetic suspension main shaft. Background Art

[0002] Since there is no mechanical contact, magnetic levitation technology has the advantages of no wear, no pollution, low power consumption, low noise, and high efficiency. The application fields of magnetic levitation technology are becoming more and more extensive, such as centrifugal compressors, high-speed motors, artificial heart pumps, energy storage flywheels, distributed power generation systems, etc. The structure of the magnetic levitation spindle is complex and expensive. Once the spindle is unstable or the bearing loses power, the spindle will fall at an ultra-high speed and hit the stator under the impact force, causing damage to the magnetic bearing and even the scrapping of the magnetic levitation system. The protective bearing is an important part of the magnetic levitation system. When the magnetic levitation system is powered off or the control system fails, the spindle falls on the protective bearing at high speed. At this time, the protective bearing temporarily supports the high-speed rotating spindle to protect the equipment from damage. However, when traditional bearings are used for radial protection of the magnetic levitation spindle, they are easily damaged when subjected to large acceleration, ultra-high speed, huge vibration and impact, and cannot effectively protect the magnetic levitation spindle. Utility Model Content

[0003] In order to solve the above technical problems, the utility model provides a radial protection angular contact ball bearing group for a magnetic suspension main shaft.

[0004] In order to achieve the above technical purpose, the technical scheme adopted is: a radial protection angular contact ball bearing group for a magnetic suspension main shaft, which is composed of N≥2 sets of angular contact ball bearings of the same model. The angular contact ball bearing is a non-full-fill rolling element and cage-free structure, including a bearing outer ring, a bearing inner ring and a rolling element. The bearing outer ring is sleeved on the outside of the bearing inner ring, and raceways are formed on the surfaces of the opposite sides of the bearing inner ring between the bearing outer rings. The rolling element is placed between the bearing outer ring raceway and the bearing inner ring raceway. The bearing outer ring raceway and the bearing inner ring raceway are both provided with a molybdenum disulfide coating or a polytetrafluoroethylene layer. An annular groove is provided on the inner diameter of the bearing inner ring, and an elastic damper providing radial elastic damping support is installed in the annular groove. The inner surface of the elastic damper protrudes from the inner diameter surface of the bearing inner ring.

[0005] Furthermore, the diameter of the rolling element is D, and the gap S between two adjacent rolling elements satisfies: 0.08*D≤S≤0.16*D.

[0006] Furthermore, the thickness of the molybdenum disulfide coating or polytetrafluoroethylene layer is 0.02-0.05 mm.

[0007] Furthermore, the depth h of the annular groove satisfies: h≤0.25(di-d), and the width l satisfies: l≤0.8B, wherein di is the bottom diameter of the raceway groove of the inner ring of the bearing, d is the diameter of the inner ring of the bearing, and B is the width of the inner ring of the bearing.

[0008] Furthermore, the elastic damper is composed of an annular spring and an annular damping strip. The annular spring is installed in an annular groove. A conical groove is provided on the inner diameter of the annular spring. The outer diameter surface of the annular damping strip is a conical surface and the inner diameter surface is a plane. The annular damping strip is interference fit into the space formed by the conical groove and the annular groove.

[0009] The beneficial effects of the utility model are:

[0010] Angular contact ball bearing sets are composed of N sets of angular contact ball bearings of the same type. The assembled bearing sets can withstand radial loads, axial loads in two directions and higher overturning moments. The angular contact ball bearing adopts a non-full-fill rolling element and cage-free structure. The outer ring raceway and the inner ring raceway are both provided with molybdenum disulfide coatings. An annular groove is provided on the inner diameter of the inner ring, and an elastic damper is provided on the annular groove. After the magnetic suspension spindle is assembled with the radial protection angular contact ball bearing, when the magnetic suspension spindle becomes unstable or the magnetic bearing loses power, the non-full-fill silicon nitride ceramic balls cooperate with the coatings on the outer raceway and the inner raceway to support the horizontally falling spindle, and effectively prevent the bearing from getting stuck and sintering while reaching high-speed rotation in an instant; before the spindle falls on the radial protection angular contact ball bearing group, it first contacts the elastic damper provided on the inner diameter end face of the inner ring. The elastic damper and the protection bearing group work simultaneously, which can timely prevent the protection bearing from vibration and impact, further increase the working speed of the protection bearing, and effectively prevent the magnetic suspension spindle from sintering and sticking to the bearing, thereby protecting the magnetic suspension spindle. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 It is a schematic diagram of the structure of the utility model;

[0012] Figure 2 It is a structural schematic diagram of the elastic damper of the utility model;

[0013] In the figure: 1, bearing outer ring, 2, outer raceway coating, 3, rolling element, 4, inner raceway coating, 5, elastic damper, 6, bearing inner ring, 7, angular contact ball bearing, 8, annular groove, 51, annular spring, 52, annular damping strip. DETAILED DESCRIPTION

[0014] The preferred embodiments of the utility model are given below in conjunction with the accompanying drawings to explain the technical solution of the utility model in detail. Here, the corresponding drawings will be given to explain the utility model in detail. It should be particularly noted that the preferred embodiments described here are only used to illustrate and explain the utility model, and are not used to limit or restrict the utility model.

[0015] In the description of this embodiment, the terms "inside", "outside", "front", "back", "left", "right", etc., indicating directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, they should not be understood as limitations on the present invention.

[0016] like Figure 1 As shown, a radial protection angular contact ball bearing group for a magnetic suspension main shaft is composed of N≥2 sets of angular contact ball bearings 7 of the same type. If N=2, two angular contact ball bearings 7 are assembled face to face. If N=3, three angular contact ball bearings 7 are assembled in three sets, which is a TFT three-set configuration. If N=3, four angular contact ball bearings 7 are assembled in four sets, which is a QFC four-set configuration. The angular contact ball bearings are non-full-fill rolling element and non-cage structure. Only the cage-free structure can promote the protection effect. The cage will not be damaged by the impact force brought by the rotor falling at an ultra-high speed. The non-full-fill rolling element will not be stuck when it is hit, resulting in friction and heat generation between the rolling element 3 and the bearing outer ring 1 and the bearing inner ring 6, causing sintering.

[0017] The angular contact ball bearing 7 includes a bearing outer ring 1, a bearing inner ring 6 and a rolling element 3. The bearing outer ring 1 is sleeved on the outside of the bearing inner ring 6. A raceway is formed on the surface of the bearing outer ring 1 on the opposite side of the bearing inner ring 6. The rolling element 3 is placed between the raceway of the bearing outer ring 1 and the raceway of the bearing inner ring 6. This part of the structure is consistent with the traditional angular contact ball bearing without a cage. In order to further protect the magnetic suspension spindle, the diameter of the rolling element 3 can be limited to D, and the gap S between two adjacent rolling elements 3 satisfies: 0.08*D≤S≤0.16*D. A molybdenum disulfide coating or a polytetrafluoroethylene layer is provided on the raceway of the bearing outer ring 1 and the raceway of the bearing inner ring 6 to play a lubricating role and prevent bearing sintering. The thickness of the molybdenum disulfide coating or the polytetrafluoroethylene layer is 0.02~0.05mm.

[0018] like Figure 1 As shown, the outer raceway coating 2 on the bearing outer ring 1 and the inner raceway coating 4 on the bearing inner ring 6 are provided by spraying or sputtering.

[0019] In order to further enhance the protection of the magnetic levitation main shaft, an annular groove 8 is provided on the inner diameter of the bearing inner ring 6, and an elastic damper 5 providing radial elastic damping support is installed in the annular groove 8 by interference fit. The elastic damper 5 is installed in the annular groove 8 through elastic deformation. The inner surface of the elastic damper 5 protrudes from the inner diameter surface of the bearing inner ring 6. When impacted, the elastic damper 5 first contacts the fallen rotor, and part of the impact force is reduced by the elastic damper 5. The elastic damper 5 can be a damping strip with greater elasticity, such as rubber, or spring steel with strong impact resistance and a certain elastic deformation force, such as a spring leaf.

[0020] The bearing outer ring 1 and the bearing inner ring 6 are made of high-strength steel, and the high-strength steel may be ZGCr15, which can be better used with the outer raceway coating 2 and the inner raceway coating 4. At the same time, the rolling element 3 is made of silicon nitride, which ensures the strength requirements for protecting the bearing and can better improve the ability to withstand impact force.

[0021] The depth h of the annular groove 8 satisfies: h≤0.25(di-d), and the width l satisfies: l≤0.8B, wherein di is the bottom diameter of the raceway groove of the bearing inner ring 6, d is the diameter of the bearing inner ring 6, and B is the width of the bearing inner ring.

[0022] like Figure 2 As shown, the elastic damper 5 is composed of an annular spring 51 and an annular damping strip 52. The outer diameter surface of the annular spring 51 is a plane, and a conical groove is provided on the inner diameter. This structure facilitates the deformation of the annular spring 51 and inserts it into the annular groove 8. The outer diameter surface of the annular spring 51 is against the bottom of the annular groove 8. The outer diameter surface of the annular damping strip 52 is a conical surface and the inner diameter surface is a plane. In coordination with the structure of the annular spring, the annular damping strip 52 is interference fit and inserted into the annular spring 51. The conical groove is a side opening shape. The annular damping strip 52 is interference fit and inserted into the space formed by the conical groove and the annular groove 8. Then, one end face of the annular damping strip 52 is against the side wall of the annular groove 8, and the other end is against the annular spring 51. When the annular damping strip 52 is deformed by force, it compresses the annular spring 51 to deform, absorbing most of the vibration and impact generated in the radial direction. The stiffness and damping coefficient of the elastic damper can also be adjusted by adjusting the thickness of the spring sheet and the damping strip.

[0023] After the magnetic levitation main shaft is assembled with radial protection angular contact ball bearings, when the magnetic levitation main shaft becomes unstable or the magnetic bearing loses power, the partially filled rolling element 3 cooperates with the outer raceway coating 2 and the inner raceway coating 4 to support the horizontally falling main shaft, and effectively prevents the bearing from getting stuck and sintering while reaching high-speed rotation in an instant; before the main shaft falls on the radial protection angular contact ball bearing group, it first contacts the elastic damper set on the inner diameter of the bearing inner ring 6, and the elastic damper 5 works simultaneously with the protection bearing, which can timely avoid the protection bearing from vibration and impact, further improve the working speed of the protection bearing, and effectively prevent the magnetic levitation main shaft from sintering and sticking to the bearing, thereby protecting the magnetic levitation main shaft.

[0024] The above are only preferred examples of the present invention and are not intended to limit or restrict the present invention. For researchers or technicians in this field, the present invention may have various modifications and variations. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention shall be included in the scope of protection declared by the present invention.

Claims

1. A radial protection angular contact ball bearing set for a magnetic suspension spindle, characterized in that: The invention is composed of N≥2 sets of angular contact ball bearings (7) of the same model. The angular contact ball bearing (7) is a non-full-fill rolling element and cage-free structure, comprising a bearing outer ring (1), a bearing inner ring (6) and a rolling element (3). The bearing outer ring (1) is sleeved on the outside of the bearing inner ring (6). A raceway is formed on the surface of the bearing outer ring (1) and the bearing inner ring (6) on one side opposite to each other. The rolling element (3) is arranged between the raceway of the bearing outer ring (1) and the raceway of the bearing inner ring (6). The raceway of the bearing outer ring (1) and the raceway of the bearing inner ring (6) are both provided with a molybdenum disulfide coating or a polytetrafluoroethylene layer. An annular groove (8) is provided on the inner diameter of the bearing inner ring (6). An elastic damper (5) providing radial elastic damping support is interference-fitted in the annular groove (8). The inner surface of the elastic damper (5) protrudes from the inner diameter surface of the bearing inner ring (6).

2. A radial protection angular contact ball bearing set for a magnetic suspension spindle according to claim 1, characterized in that: The diameter of the rolling body (3) is D, and the gap S between two adjacent rolling bodies (3) satisfies: 0.08*D≤S≤0.16*D.

3. A radial protection angular contact ball bearing set for a magnetic suspension spindle according to claim 1, characterized in that: The thickness of the molybdenum disulfide coating or polytetrafluoroethylene layer is 0.02-0.05 mm.

4. A radial protection angular contact ball bearing set for a magnetic suspension spindle according to claim 1, characterized in that: The depth h of the annular groove (8) satisfies: h≤0.25(di-d), and the width l satisfies: l≤0.8B, wherein di is the bottom diameter of the raceway groove of the bearing inner ring (6), d is the diameter of the bearing inner ring (6), and B is the width of the bearing inner ring.

5. A radial protection angular contact ball bearing set for a magnetic suspension main shaft according to claim 1, characterized in that: The elastic damper (5) is composed of an annular spring (51) and an annular damping strip (52). The annular spring (51) is installed in the annular groove (8). A conical groove is provided on the inner diameter of the annular spring (51). The outer diameter surface of the annular damping strip (52) is a conical surface and the inner diameter surface is a flat surface. The annular damping strip (52) is interference-fitted into the space formed by the conical groove and the annular groove (8).

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