CN113236671A

CN113236671A - Novel active magnetic-gas hybrid bearing based on PZT stack

Info

Publication number: CN113236671A
Application number: CN202110626709.2A
Authority: CN
Inventors: 冯利博; 张航; 殷钱伟; 周翔; 冯凯
Original assignee: Hunan University
Current assignee: Hunan University
Priority date: 2021-06-04
Filing date: 2021-06-04
Publication date: 2021-08-10
Anticipated expiration: 2041-06-04
Also published as: CN113236671B

Abstract

The invention provides a novel active magnetic-air hybrid bearing based on a PZT stack, which comprises a stator, an air foil assembly and the PZT stack assembly, wherein the air foil assembly comprises an air foil bearing seat, a wave foil and a top foil, the top foil covers the inner surface of the wave foil and is arranged in the air foil bearing seat together, the PZT stack assembly comprises two PZT stack fixing blocks, a PZT stack cushion block and the PZT stack, the PZT stack fixing block is connected with the stator, the PZT stack is clamped between the two PZT stack fixing blocks, the top end of the PZT stack is abutted against the stator, the bottom end of the PZT stack is abutted against the PZT cushion block, the air foil bearing seat is provided with a notch corresponding to the PZT stack cushion block in a penetrating way along the radial direction, the PZT stack cushion block penetrates through the notch and is abutted against the wave foil, and the PZT stack is radially deformed after being electrified, and driving the wave foil to deform. The novel active magnetic-gas hybrid bearing based on the PZT stack has high operation stability.

Description

Novel active magnetic-gas hybrid bearing based on PZT stack

[ technical field ] A method for producing a semiconductor device

The invention relates to the technical field of bearings, in particular to a novel active magnetic-gas hybrid bearing based on a PZT stack.

[ background of the invention ]

The air foil bearing is composed of a bearing seat and one or more layers of foils, when a rotor runs at a high speed, relative motion is generated between the rotor and the bearing to form a wedge-shaped space, air is used as a lubricating medium to continuously extrude viscous gas in the wedge-shaped space, and the corrugated foils are elastically deformed to form a lubricating gas film supporting load with rigidity and damping. The lubricating air film generated when the rotor rotates at high speed separates the rotor from the bearing, so that the dry friction phenomenon can not occur. However, the air foil bearing has low bearing capacity and high friction in the low-speed stage, so that the rotor and the foil can be worn.

The active electromagnetic bearing is a non-contact bearing which suspends the rotor by using controllable electromagnetic force between the stator and the rotor. The controller controls the current in the magnetic pole coil according to the displacement signal of the rotor, so that the rotor stably runs and is suspended at a certain position. Therefore, the rigidity and the damping of the active electromagnetic bearing are adjustable and controllable, and the position of the rotor can be dynamically controlled in real time. The active electromagnetic bearing completely avoids friction due to no mechanical contact between the stator and the rotor. However, the active electromagnetic bearing needs to be assisted by a protective bearing, and a closed-loop control system is additionally needed, so that the electromagnetic bearing is easily affected by resonance generated when the rotor rotates at a high speed, and the stability of the system is reduced.

It is therefore desirable to provide a new active magnetic/air hybrid bearing based on PZT stacks to address the above problems.

[ summary of the invention ]

The invention discloses a novel active magnetic-gas hybrid bearing based on a PZT stack.

In order to achieve the purpose, the technical scheme of the invention is as follows:

a novel active magnetic-air hybrid bearing based on a PZT stack comprises a stator, an air foil assembly and a PZT stack assembly, wherein the air foil assembly is arranged in a hollow area on the inner side of the stator, the air foil assembly comprises an air foil bearing seat, a wave foil and a top foil, the top foil covers the inner surface of the wave foil, the air foil assembly and the wave foil are arranged in the air foil bearing seat together, the PZT stack assembly comprises two PZT stack fixing blocks, a PZT stack cushion block and a PZT stack, the PZT stack fixing block is connected with the stator, the PZT stack is clamped between the two PZT stack fixing blocks, the top end of the PZT stack is abutted against the stator, the bottom end of the PZT stack cushion block is abutted against the PZT stack cushion block, a notch is arranged in the position of the air foil bearing seat corresponding to the PZT stack cushion block in a penetrating way along the radial direction, and the PZT stack cushion block penetrates through the notch and is abutted against the wave foil, and the PZT stack is subjected to radial deformation after being electrified, so that the wave foil is driven to deform.

Preferably, the number of the PZT stack assemblies is multiple, and the multiple PZT stack assemblies are distributed in an annular array along the central axis of the bump foil.

Preferably, two PZT stack fixed blocks and one PZT stack group is constituteed jointly to the PZT stack, the PZT stack cushion is followed the axial direction of ripples foil sets up, just the both ends of PZT stack cushion with the both ends of ripples foil flush, every be equipped with two on the PZT stack cushion the PZT stack group, two PZT stack group symmetry set up in PZT stack cushion both ends.

Preferably, the stator includes a stator core, two insulating plates and a coil, the two insulating plates are symmetrically disposed at two ends of the stator core, the stator core includes a stator yoke and a plurality of stator teeth fixed on the stator yoke, the stator yoke is a hollow cylinder, and the plurality of stator teeth are uniformly distributed on an inner circumferential surface of the stator yoke; the insulating plate comprises a rib plate and a plurality of partition plates fixed on the rib plate, the partition plates are uniformly distributed on one side of the rib plate, a gap is formed between every two adjacent partition plates at intervals, and the stator tooth part is inserted into the gap.

Preferably, the partition plate comprises a top plate, two side plates which are bent and extended from two sides of the top plate to the axis direction, and flanges which are bent and extended from the tail ends of the two side plates in opposite directions, the coil is wound on the two adjacent side plates in the two adjacent partition plates, and the flanges limit the coil.

Preferably, the PZT stack fixing blocks include a main body portion and connecting portions fixed to the top end of the main body portion, one connecting portion is disposed on each main body portion, two connecting portions of the two PZT stack fixing blocks are spaced from each other to form a T-shaped sliding groove, a sliding block is formed on the top plate in a protruding manner at a position corresponding to the sliding groove, the shape of the sliding block is matched with that of the sliding groove, the sliding block is correspondingly accommodated in the sliding groove, and the top end of the PZT stack abuts against the sliding block.

Preferably, the number of the air foil bearing seats is two, the two air foil bearing seats are spliced into a whole, the two air foil bearing seats are symmetrically arranged relative to a splicing surface, an opening avoiding the stator tooth part is arranged on the air foil bearing seat in a penetrating mode along the radial direction, and the stator tooth part penetrates through the opening and abuts against the bump foil.

Preferably, the air foil assembly further includes a cylindrical pin, a pin hole is axially formed in the air foil bearing seat, a first fixing section is formed by bending the end of the wave foil, a second fixing section is formed by bending the end of the top foil, the first fixing section and the second fixing section are embedded into the pin hole after being overlapped, and the cylindrical pin is correspondingly inserted into the pin hole to fix the wave foil and the top foil.

Preferably, the PZT stack cushion block comprises a bottom wall and side walls bent and extended from two ends of the bottom wall, the bottom wall and the side walls are matched to form a U-shaped groove body structure, the bottom end of the PZT stack is abutted to the bottom wall, the bottom wall is abutted to the wave foil, and the two PZT stack fixing blocks are respectively abutted to the two side walls.

Preferably, the wave foil comprises a plane section and a curved section which are alternately arranged in sequence, the curved section is arched towards the axis direction, the curved section and the air foil bearing seat form a wedge-shaped space at an interval, and the PZT stack cushion block abuts against the plane section.

Compared with the prior art, the PZT stack is arranged in the novel active magnetic-air hybrid bearing based on the PZT stack, and the gap of the air foil bearing is adjusted by changing the voltage of the bearing, so that the rigidity of the hybrid bearing is adjustable, the stability of the rotor in high-speed operation is improved, a lubricating and sealing system is not needed, the power loss is small, and the novel active magnetic-air hybrid bearing based on the PZT stack is more suitable for high-speed operation occasions.

[ description of the drawings ]

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the description of the embodiments are briefly introduced below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and other drawings can be obtained by those skilled in the art without inventive efforts, wherein:

fig. 1 is a schematic perspective view of a novel active magnetic-gas hybrid bearing based on a PZT stack according to the present invention;

FIG. 2 is a cross-sectional view of the novel active magnetic/air hybrid bearing based on a PZT stack shown in FIG. 1 taken along line I-I;

FIG. 3 is an enlarged view of area A shown in FIG. 2;

FIG. 4 is an enlarged view of area B shown in FIG. 2;

FIG. 5 is an exploded view of the stator;

FIG. 6 is an exploded view of an air foil assembly;

figure 7 is an exploded view of a PZT stack assembly.

[ detailed description ] embodiments

The following description of the present invention is provided to enable those skilled in the art to better understand the technical solutions in the embodiments of the present invention and to make the above objects, features and advantages of the present invention more comprehensible.

The endpoints of the ranges and any values disclosed herein are not limited to the precise range or value, and such ranges or values should be understood to encompass values close to those ranges or values. For ranges of values, between the endpoints of each of the ranges and the individual values, and between the individual values may be combined with each other to yield one or more new ranges of values, which ranges of values should be considered as specifically disclosed herein.

Referring to fig. 1-7, the present invention provides a novel active magnetic gas hybrid bearing 100 based on PZT stacks, which includes a stator 10, an air foil assembly 20, and a PZT stack assembly 30.

The stator 10 includes a stator core 11, an insulating plate 12, and a coil 13.

The stator core 11 includes a stator yoke portion 111 and a plurality of stator teeth portions 112 fixed to the stator yoke portion 111, and the stator yoke portion 111 and the stator teeth portions 112 are integrally molded. The stator yoke 111 has a hollow cylindrical shape, and a plurality of stator teeth 112 are uniformly distributed on an inner circumferential surface of the stator yoke 111.

The number of the insulating plates 12 is two, and the two insulating plates 12 are symmetrically arranged at two ends of the stator core 11. The insulating plate 12 includes a rib plate 121 and a plurality of spacers 122 fixed to the rib plate 121, the plurality of spacers 122 are uniformly distributed on one side of the rib plate 121, and a gap 123 is formed between two adjacent spacers 122. When the stator is mounted, the spacers 122 of the two insulating plates 12 are aligned in contact with each other, the spacers 122 are inserted into the hollow regions of the stator yoke 111, and the stator teeth 112 are inserted into the gaps 123.

The insulating plate 12 is formed by processing through a 3D printing technology, the diameter of the outer circle of the insulating plate is equal to that of the outer circle of the stator core 11, and the inner circle formed after the insulating plate is assembled with the stator core 11 is used for installing the air foil assembly 20.

Further, the partition 122 includes a top plate 1221, two side plates 1222 bent and extended from two sides of the top plate 1221, and flanges 1223 bent and extended from ends of the two side plates 1222 toward each other. The coil 13 is wound on two adjacent side plates 1222 of two adjacent partition plates 122, and the flanges 1223 can limit the coil 13, so as to prevent the coil 13 from falling off the side plates 1222. It is understood that the coil 13 is wound around the periphery of the stator teeth 112.

The air foil assembly 20 is mounted inside the stator 10 in a hollow area, and includes an air foil bearing seat 21, a bump foil 22, a top foil 23, and a cylindrical pin 24.

The number of the air foil bearing seats 21 is two, the two air foil bearing seats 21 are spliced into a whole, and the two air foil bearing seats 21 are symmetrically arranged about a splicing surface. An opening 210 is formed in the air foil bearing seat 21 in a radial direction so as to avoid the stator teeth 112, and the stator teeth 112 pass through the opening 210 and abut against the bump foil 22.

The top foil 23 covers the inner surface of the bump foil 22, and the top foil and the bump foil 22 are installed together in the air foil bearing seat 21, the air foil bearing seat 21 is provided with a pin hole 211 along the axial direction, the end of the bump foil 22 is bent to form a first fixing section 221, the end of the top foil 23 is bent to form a second fixing section 231, the first fixing section 221 and the second fixing section 231 are overlapped and then embedded in the pin hole 211, and the cylindrical pin 24 is correspondingly inserted into the pin hole 211 to fix the bump foil 22 and the top foil 23.

The PZT stack assembly 30 includes a PZT stack fixing block 31, a PZT stack spacer 32, and a PZT stack 33.

The number of the PZT stack fixing blocks 31 is two, the two PZT stack fixing blocks 31 are spaced from each other, the PZT stacks 33 are clamped between the two PZT stack fixing blocks 31, and the two PZT stack fixing blocks 31 and one PZT stack 33 jointly form a PZT stack group. The PZT stack cushion blocks 32 are arranged along the axial direction of the wave foil 22, the two ends of the PZT stack cushion blocks 32 are flush with the two ends of the wave foil 22, each PZT stack cushion block 32 is provided with two PZT stack groups, and the two PZT stack groups are symmetrically arranged at the two ends of the PZT stack cushion block 32, so that the stress balance at the two ends of the PZT stack cushion block 32 can be ensured, and further the stress balance at the two ends of the wave foil 22 can be ensured.

The PZT stack fixing block 31 includes a body portion 311 and a connecting portion 312 fixed to a top end of the body portion 311, and the connecting portion 312 and the body portion 311 are integrally formed. Each of the body portions 311 is provided with one of the connecting portions 312, the connecting portion 312 is an inverted L-shaped structure, and two connecting portions 312 of the two PZT stack fixing blocks 31 are spaced from each other to form a T-shaped sliding slot 313.

Furthermore, a slide block 1224 is convexly formed at a position of the top plate 1221 corresponding to the sliding slot 313, the shape of the slide block 1224 matches with the shape of the sliding slot 313, the slide block 1224 is correspondingly accommodated in the sliding slot 313, and the top end of the PZT stack 33 abuts against the slide block 1224.

The air foil bearing seat 21 is provided with a notch 212 penetrating in the radial direction at a position corresponding to the PZT stack pad 32, and the PZT stack pad 32 passes through the notch 212 and abuts against the bump foil 22.

PZT storehouse cushion 32 includes diapire 321 and certainly lateral wall 322 that the both ends of diapire 321 are buckled and are extended, diapire 321 with lateral wall 322 cooperation forms the cell body structure of U-shaped, PZT storehouse 33's bottom butt the diapire, two PZT storehouse fixed block 31 butt two respectively lateral wall 322, PZT storehouse cushion 32 with PZT storehouse fixed block 31 cooperate right PZT storehouse 33 forms spacingly, makes PZT storehouse 33's deformation direction is radial direction all the time.

Preferably, the bump foil 22 includes a planar section 22a and a curved section 22b alternately arranged in sequence, the curved section 22b is arched toward the axial direction, the curved section 22b and the air foil bearing seat 21 form a wedge-shaped space 22c at an interval, and the size of the wedge-shaped space 22c affects the rigidity and damping of the bearing. The processing process of the wave foil 22 is as follows: firstly, carrying out heat treatment, after the heat treatment is finished, sticking the blank to a designed die for stamping and forming, and then carrying out second heat treatment to further form the blank.

Piezoelectric ceramics (PZT) is a functional electronic ceramic material that can interconvert electrical and mechanical energy. When voltage is applied to the piezoelectric ceramic in the polarization direction, deformation displacement occurs along with the piezoelectric ceramic, and after the voltage is removed, the deformation disappears, so that the PZT generates mechanical deformation by utilizing the inverse piezoelectric effect. Since the amount of deformation of the ceramic piezoelectric ceramics is very small, a plurality of piezoelectric ceramic pieces can be stacked to form the piezoelectric PZT stack 33 to increase the upper limit of the elongation thereof, and the amount of deformation of the PZT stack 33 can be controlled very accurately by changing the magnitude of the voltage and the frequency.

The PZT stacks 33 are communicated with an external power supply, the PZT stacks 33 generate deformation displacement with different sizes in the radial direction by changing the voltage of the PZT stacks 33, the deformation displacement is transmitted to the wave foil 22 through the PZT stack cushion block 32, the wave foil 22 is extruded, the wedge-shaped space of the wave foil 22 is changed, and finally the rigidity and the damping of the bearing are changed.

The PZT stack pad 32 abuts against the planar section 22a, and since the bottom wall 321 of the PZT stack pad 32 is also planar on the surface contacted with the planar section 22a, the contact area between the PZT stack pad 32 and the bump foil 22 can be increased, and a better driving effect is ensured.

The number of the PZT stack assemblies 30 is multiple, and the PZT stack assemblies 30 are distributed in an annular array along the central axis of the wave foil 22, so that the uniform stress of the circumferential surface of the wave foil 22 can be ensured.

The novel active magnetic-gas hybrid bearing 100 based on the PZT stack is a composite bearing of an active electromagnetic bearing and an air foil bearing, and makes full use of the space of the active electromagnetic bearing, so that the whole structure is compact. When the rotor rotates at a low speed, the load is mainly provided by the active electromagnetic bearing, so that the problems of low bearing capacity and high friction of the air foil bearing at the low speed stage can be solved, the abrasion of the rotor and the foil can be reduced, and the service life can be prolonged; when the rotor is in high speed, the air foil bearing mainly provides load, so that the problem of high-speed stage resonance of the active electromagnetic bearing can be avoided, meanwhile, the PZT stack 33 is mechanically deformed by applying voltages with different magnitudes to change the radial elongation of the PZT stack, the bump foil 22 in contact with the PZT stack cushion block 32 is influenced, the air film thickness of the air foil bearing is further changed, the wedge-shaped space 33c is increased, the effects of increasing the rigidity of the air foil bearing and reducing the cross coupling rigidity of the air foil bearing are achieved, and finally the purposes of changing the air film thickness and improving the stability of the hybrid bearing are achieved.

Claims

1. A novel active magnetic-air hybrid bearing based on a PZT stack is characterized by comprising a stator, an air foil assembly and a PZT stack assembly, wherein the air foil assembly is arranged in a hollow area on the inner side of the stator, the air foil assembly comprises an air foil bearing seat, a wave foil and a top foil, the top foil covers the inner surface of the wave foil, the air foil assembly and the wave foil are arranged in the air foil bearing seat together, the PZT stack assembly comprises two PZT stack fixing blocks, a PZT stack cushion block and a PZT stack, the PZT stack fixing blocks are connected with the stator, the PZT stack clamp is arranged between the two PZT stack fixing blocks, the top end of the PZT stack is abutted against the stator, the bottom end of the PZT stack cushion block is abutted against the PZT stack cushion block, a notch is arranged in the position of the air foil bearing seat corresponding to the PZT stack cushion block in a penetrating manner along the radial direction, the PZT stack cushion block penetrates through the notch and is abutted against the wave foil, and the PZT stack is subjected to radial deformation after being electrified, so that the wave foil is driven to deform.

2. The PZT stack-based novel active magnetic-air hybrid bearing of claim 1, wherein the number of PZT stack assemblies is plural, and the plural PZT stack assemblies are distributed in an annular array along a central axis of the bump foil.

3. The PZT stack-based novel active magnetic-air hybrid bearing of claim 1, wherein two of the fixed blocks of the PZT stacks and one of the PZT stacks together form a PZT stack group, the block of the PZT stacks is disposed along an axial direction of the wave foil, and both ends of the block of the PZT stacks are flush with both ends of the wave foil, two of the PZT stack groups are disposed on each block of the PZT stacks, and the two PZT stack groups are symmetrically disposed at both ends of the block of the PZT stacks.

4. The novel active magnetic-air hybrid bearing based on PZT stack as claimed in claim 1, wherein the stator comprises a stator core, two insulation plates and a coil, the two insulation plates are symmetrically arranged at two ends of the stator core, the stator core comprises a stator yoke and a plurality of stator teeth fixed on the stator yoke, the stator yoke is hollow cylinder-shaped, and the plurality of stator teeth are uniformly distributed on the inner circumferential surface of the stator yoke; the insulating plate comprises a rib plate and a plurality of partition plates fixed on the rib plate, the partition plates are uniformly distributed on one side of the rib plate, a gap is formed between every two adjacent partition plates at intervals, and the stator tooth part is inserted into the gap.

5. The PZT stack-based novel active magnetic-air hybrid bearing according to claim 4, wherein the partition plate comprises a top plate, two side plates bending and extending from two sides of the top plate to the axial direction, and flanges bending and extending from the ends of the two side plates to the opposite direction, the coil is wound on two adjacent side plates of two adjacent partition plates, and the flanges limit the coil.

6. The novel active magnetic-air hybrid bearing based on PZT stack as claimed in claim 5, wherein the PZT stack fixing block includes a body portion and connecting portions fixed on the top end of the body portion, one connecting portion is disposed on each body portion, two connecting portions of the two PZT stack fixing blocks are spaced from each other to form a T-shaped sliding slot, a slider is formed on the top plate at a position corresponding to the sliding slot, the shape of the slider matches the shape of the sliding slot, the slider is correspondingly accommodated in the sliding slot, and the top end of the PZT stack is abutted to the slider.

7. The PZT stack based novel active magnetic-air hybrid bearing according to claim 4, wherein the number of the air foil bearing seats is two, the two air foil bearing seats are spliced into a whole, the two air foil bearing seats are symmetrically arranged about a splicing surface, an opening avoiding the stator tooth part is arranged on the air foil bearing seat in a penetrating way along a radial direction, and the stator tooth part passes through the opening and abuts against the wave foil.

8. The novel active magnetic-air hybrid bearing based on a PZT stack as claimed in claim 1, wherein the air foil assembly further comprises a cylindrical pin, the air foil bearing seat is axially provided with a pin hole, the end of the wave foil is bent to form a first fixing section, the end of the top foil is bent to form a second fixing section, the first fixing section and the second fixing section are overlapped and then embedded into the pin hole, and the cylindrical pin is correspondingly inserted into the pin hole to fix the wave foil and the top foil.

9. The PZT stack based novel active magnetic-air hybrid bearing according to claim 1, wherein the PZT stack cushion block comprises a bottom wall and side walls extending from two ends of the bottom wall in a bending way, the bottom wall and the side walls are matched to form a U-shaped groove body structure, the bottom end of the PZT stack is abutted against the bottom wall, the bottom wall is abutted against the wave foil, and two PZT stack fixing blocks are respectively abutted against two side walls.

10. The PZT stack based novel active magnetic-air hybrid bearing according to claim 1, wherein the wave foil comprises a plane section and a curved section which are alternately arranged in sequence, the curved section is arched towards the axial direction, the curved section and the air foil bearing seat are spaced to form a wedge-shaped space, and the PZT stack cushion block is abutted against the plane section.