Dynamic balance rotor system of air suspension bearing and manufacturing process of dynamic balance rotor system

Abstract

The invention discloses a structure and a manufacturing process of a dynamic balance rotor system of an air bearing, and belongs to the field of air suspension rotation. The problem to be solved is optimization of the structure and the manufacturing process of the air suspension rotating rotor system. The interference fit is completed by improving the structure of the rotor core of the rotor system and ingeniously applying thermal expansion and cold contraction, so that the surface of the whole rotor system is smooth, the dynamic balance effect is good, the manufacturing cost is reduced, and the manufacturing period is shortened. The bearing can be used on various rotating shafts supported by suspension bearings, such as magnetic suspension and / or air suspension bearings.

Description

Technical Field

[0001] The invention belongs to the field of air suspension rotation, and in particular relates to a dynamic balance rotor system of an air suspension bearing. Background Art

[0002] At present, the air-floating shaft with the impeller installed in the air-floating bearing blower is supported by a dynamic pressure air-floating bearing. This type of air-floating shaft has a take-off speed. Only when the speed reaches a certain level, the air gap between the air-floating bearing and the shaft core can reach enough pressure to float the shaft. This is bound to lead to high requirements for the speed of the shaft core and the dynamic balance of the rotor system where the shaft core is located. As a result, the structure and manufacturing process of the rotor system are relatively complicated. For example, the magnetic steel in the motor rotor core that matches the motor stator in the rotor system is installed in the shaft after magnetization, and then sealed by welding, and then stress relief is required. Under such a cumbersome process, the shaft is finely processed to have a low imbalance to meet the stability required for high-speed rotation of the rotor system. There are requirements for the materials and structures of each component, and the processing cycle is long and the cost is high. Summary of the invention

[0003] The present invention aims to solve the problems of high material and structural requirements for various parts of a low dynamic balance rotor system under welding technology, long processing cycle and high cost caused by difficult manufacturing technology.

[0004] The invention discloses a dynamic balancing rotor system of an air suspension bearing, which looks like an integral molding, smooth and without welds. In fact, the dynamic balancing rotor system of the air suspension bearing is an assembly component, including an axis core and a rotor core component sleeved on the axis core, and an end face cover plate of the rotor core component; the position of the rotor core component on the axis core is set by a limiting step; the rotor core component includes an iron core, and a plurality of holes evenly distributed along the axial direction are provided on the cylindrical surface of the rotor core, and magnetized magnetic steel is inserted into the holes; after the magnetic steel is inserted into the hole of the rotor core, the end face of the rotor core is provided with a cover plate to cover the magnetic steel in the hole, and the cover plate is coaxially installed on the axis core; the structural dimensions of the magnetic steel, its cover plate and the rotor core in which it is located are calculated according to the requirement that the entire rotor system must meet the dynamic balancing state.

[0005] A preferred technical solution is that the plurality of evenly distributed holes are through holes that penetrate the cylindrical surface of the core, and two identical magnetic steels are inserted into each through hole, the two identical magnetic steels are connected axially, and both ends are not higher than the end surface of the rotor core; the two end surfaces of the rotor core are covered with a cover plate to cover the magnetic steel.

[0006] A preferred technical solution is that the magnetic steel is made of neodymium iron boron with a temperature resistance of 130°C; the rotor core uses silicon steel sheets with a yield strength of not less than 430MPa; the cover plate is made of aluminum alloy; the shaft core material is 95Cr18; the appearance of the magnetic steel is the same as the shape of the through hole in the cylindrical surface of the rotor core, and the radial cross-sectional gap is 0.1mm~0.16mm; the end face size of the cover plate is the same as the shape and size of the end face of the core.

[0007] The manufacturing process of the above rotor system is completed through the following steps: The first step is to determine the relevant dimensions and matching clearances of the magnetic steel and the rotor core, the rotor core assembly, the magnetic steel cover plate and the shaft core through theoretical calculation and simulation calculation to meet the dynamic balance requirements of the rotor system. The second step is to magnetize the magnetic steel, apply glue and insert it into the hole of the rotor core; place the assembled rotor core assembly in the pressing tool and use a press to press it with a pressing pressure of 1 ton and a holding time of 2 hours. After 2 hours, take out the rotor core assembly and place it in a clean place for no less than 22 hours to allow the glue to solidify; The third step is to select interference fit between the rotor core assembly and the shaft core during design, and then use the principle of thermal expansion and contraction to perform interference fit assembly: cool down the shaft core, heat up the rotor core assembly including the magnetic steel and the cover plate respectively, and then assemble the cover plate, rotor core assembly and cover plate on the shaft core in sequence to complete the pre-assembly of the rotor system; Step 4: Use a tool and a press to compact the assembled rotor system with a compaction force of 1 ton. After the temperature of the rotor system is balanced to room temperature, take it out and let it stand for no less than 12 hours. The fifth step is to place the entire rotor system in a heating box for water heating at a temperature of 100°C for at least 4 hours, followed by natural or air cooling to room temperature. The rotor system is then dynamically balanced to verify all design and process effects.

[0008] A preferred technical solution is that when implementing the third step of the above process solution, the temperature of the shaft core is reduced to -190°C, the temperature of the cover plate is increased to 180°C, and the temperature of the rotor core assembly is increased to 80°C; wherein the cooling is preferably performed by immersing in liquid nitrogen.

[0009] The technical effect of the present invention is as follows: after improving the structure and manufacturing method of the rotor core, the present invention can greatly reduce the manufacturing difficulty of the rotor system of the air bearing blower, greatly shorten the manufacturing cycle and cost of the shaft, including material cost; at the same time, since no welding is required, the rotor imbalance is extremely small, the initial dynamic balance is one order of magnitude smaller than the original structure, the rotor state is stable, and it is conducive to the dynamic balance of the rotor; it has been verified in practice that the same model can reduce 30% of the material and process costs and reduce the production cycle by 3-5 days after adopting the invented dynamically balanced rotor system. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 Appearance of the rotor system Figure 2 Structural diagram of the rotor system Figure 3 Components of the rotor core Figure 4 Rotor core assembly of embodiment 1 Figure 5 Tooling for tightening the rotor core Figure 6 Assembly diagram of the rotor core assembly of Example 2 Among them, 1- shaft core 2- rotor core assembly 3- cover plate 4- rotor core 5- magnetic steel 6- rotor core tooling base 7- rotor core tooling pressure cover Specific embodiments Example 1

[0012] like Figure 1 The dynamic balancing rotor system shown in the figure looks like a smooth, weld-free, integrated rotor system. Figure 2 The invention comprises an axial core 1, a rotor core assembly 2 formed by sleeved on the axial core, and an end face cover plate 3 of the rotor core assembly; the position of the rotor core assembly 2 on the axial core 1 is defined by a step on the axial surface, such as Figure 2 A in the rotor core assembly 2, such as Figure 3 and 4As shown, it includes an iron core 4, and a plurality of holes evenly distributed along the axial direction are provided on the cylindrical surface of the rotor iron core, and magnetized magnetic steel 5 is inserted into the holes; after the magnetic steel 5 is inserted into the hole of the rotor iron core 4, the end surface of the rotor iron core 4 is provided with a cover plate 3 to cover the magnetic steel 5 in the hole, and is coaxially installed on the shaft core 1 together; the structural dimensions of the magnetic steel 5 and its cover plate 3 and the rotor iron core 4 in which it is located are calculated based on the requirement that the entire rotor system must meet the dynamic balance state: the appearance of the magnetic steel 5 is the same as the shape of the through hole in the cylindrical surface of the rotor iron core, and the assembly clearance of the radial section is in the range of 0.1mm~0.16mm; the end surface size of the cover plate 3 is the same as the shape size of the end surface of the iron core.

[0013] In this embodiment, the material of the magnetic steel 5 is neodymium iron boron with a temperature resistance of 130°C; the rotor core 4 is made of silicon steel sheet with a yield strength of not less than 430MPa; the cover plate 3 is made of aluminum alloy; the material of the shaft core 1 is 95Cr18; Based on the calculation of the above structure and materials, although theoretically the temperature difference between the shaft core and the cover plate should reach 300°C, and the temperature difference between the rotor core and the shaft core should reach 160°C, in actual implementation, we immersed the shaft core in liquid nitrogen, the temperature dropped to -190°C, the temperature of the cover plate rose to 180°C, and the temperature of the rotor core rose to 80°C, because it has been verified in practice that such a temperature can achieve a better assembly effect.

[0014] During the production process, the magnetic steel 5 is first magnetized and coated with glue. Figure 3 As shown, the magnetic steel 5 is inserted into the hole of the rotor core 4. Figure 4 As shown, one piece is inserted into each hole. Figure 5 As shown, the assembled rotor core assembly is placed in a pressing fixture and pressed by a press with a pressing pressure of 1 ton and a holding time of 2 hours. After 2 hours, the rotor core assembly 2 is taken out and placed in a clean place for not less than 22 hours to allow the glue to solidify; since the rotor core assembly 2 and the shaft core 1 are designed to have an interference fit, the shaft core 1 can only be cooled down, and the rotor core assembly 2 and the cover plate 3 including the magnetic steel 5 are heated up respectively, and then the cover plate 3, the rotor core assembly 2, and the cover plate 3 are assembled on the shaft core 1 in sequence to complete the pre-assembly of the rotor system; then the assembled rotor system is pressed by a fixture and a press with a pressing force of 1 ton, and the rotor system is taken out after the temperature is balanced to room temperature, and is left to stand for not less than 24 hours; finally, the entire rotor system must be placed in a heating box for water heating at a temperature of 100°C (water heating for 4 hours), and then placed naturally or air-cooled to room temperature, and then the rotor system is subjected to a dynamic balance test to verify all the design and process effects. Example 2

[0015] like Figure 6In this embodiment 2, based on the process steps and structural design ideas of embodiment 1, the hole of the rotor core where the magnetic steel is located is designed as a through hole in view of the large cylindrical length of the rotor core 4. Because the cylindrical length of the rotor core of embodiment 2 is much larger than that of embodiment 1, two axially connected magnetic steels are inserted into each through hole, so that the magnetic steel 5 can be easily inserted into the hole of the rotor core 4 and the entire rotor core assembly 2 can be easily maintained in its proper state.

[0016] The rotor system design in the above embodiment is implemented through the above process steps obtained through professional theoretical calculations and practical exploration. The final technical effect is not only a smooth appearance without welds, but also highly tight connection of components, like an integrally formed part, which can meet the dynamic balancing technical requirements of the rotor system.

[0017] After improving the structure and manufacturing method of the rotor core, the present invention greatly reduces the difficulty of manufacturing the rotor system of the air bearing blower, greatly shortens the manufacturing cycle and cost, including material cost; at the same time, since no welding is required, the rotor imbalance is extremely small, the initial dynamic balance is one order of magnitude smaller than the original structure, the rotor state is stable, and it is conducive to the dynamic balance of the rotor; it has been verified in practice that the same model can reduce 30% of the material and process costs and reduce the production cycle by 3-5 days after adopting the invented dynamically balanced rotor system.

Claims

1. A dynamic balance rotor system of an air suspension bearing, characterized in that: The appearance looks like a smooth, weld-free, one-piece molding, but it is actually the dynamically balanced rotor system, including an axis core, a rotor core assembly formed by sleeves on the axis core, and an end cover plate of the rotor core assembly; the position of the rotor core assembly on the axis core is limited by a limit step provided on the axis surface as required; the rotor core assembly includes an iron core, and a plurality of holes evenly distributed along the axial direction are provided on the cylindrical surface of the rotor core, and magnetized magnetic steel is inserted into the holes; after the magnetic steel is inserted into the holes of the rotor core, a cover plate is provided on the end face of the rotor core to cover the magnetic steel in the holes, and the two are coaxially mounted on the axis core; the structural dimensions of the magnetic steel, its cover plate, and the rotor core in which it is located are calculated based on the requirement that the entire rotor system must meet the dynamic balance state.

2. The dynamically balanced rotor system according to claim 1, characterized in that: The plurality of evenly distributed holes are through holes penetrating the cylindrical surface of the core, and two identical magnetic steels are inserted into each through hole. The two identical magnetic steels are connected axially, and both ends are not higher than the end surface of the rotor core; the two end surfaces of the rotor core are covered with a cover plate to cover the magnetic steel.

3. The dynamically balanced rotor system according to claim 2, characterized in that: The magnetic steel is made of neodymium iron boron with a temperature resistance of 130°C; the rotor core uses silicon steel sheets with a yield strength of not less than 430MPa; the cover plate is made of aluminum alloy; the shaft core material is 95Cr18; the appearance of the magnetic steel is the same as the shape of the through hole in the cylindrical surface of the rotor core, and the radial cross-sectional gap is 0.1mm~0.16mm; the end face size of the cover plate is the same as the shape and size of the end face of the core.

4. The manufacturing process of the dynamically balanced rotor system according to claim 1-2, characterized in that: Made through the following steps: The first step is to determine the relevant dimensions and matching clearances of the magnetic steel and the rotor core, the rotor core assembly, the magnetic steel cover plate and the shaft core through theoretical calculation and simulation calculation to meet the dynamic balance requirements of the rotor system. The second step is to magnetize the magnetic steel, apply glue and insert it into the hole of the rotor core; place the assembled rotor core assembly in the pressing tool and use a press to press it with a pressing pressure of 1 ton and a holding time of 2 hours. After 2 hours, take out the rotor core assembly and place it in a clean place for no less than 22 hours to allow the glue to solidify; The third step is to select interference fit between the rotor core assembly and the shaft core during design, and then use the principle of thermal expansion and contraction to perform interference fit assembly: cool down the shaft core, heat up the rotor core assembly including the magnetic steel and the cover plate respectively, and then assemble the cover plate, rotor core assembly and cover plate on the shaft core in sequence to complete the pre-assembly of the rotor system; Step 4: Use a tool and a press to compact the assembled rotor system with a compaction force of 1 ton. After the temperature of the rotor system is balanced to room temperature, take it out and let it stand for no less than 12 hours. The fifth step is to place the entire rotor system in a heating box for water heating at a temperature of 100°C for 4 hours. Then place it naturally or air cool it to room temperature. Perform a dynamic balance test on the rotor system to verify all design and process effects.

5. The manufacturing process of the dynamically balanced rotor system according to claim 4, characterized in that: When implementing the third step in the claims, for the dynamically balanced rotor system described in claim 3, the temperature of the shaft core is reduced to -190°C by immersing in liquid nitrogen, the temperature of the cover plate is increased to 180°C, and the temperature of the rotor core assembly is increased to 80°C.

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