CN111442030A

CN111442030A - Air supporting system

Info

Publication number: CN111442030A
Application number: CN202010317720.6A
Authority: CN
Inventors: 李东明; 贾颖; 胡红英; 高天一; 吕帅
Original assignee: Dalian Minzu University
Current assignee: Dalian Minzu University
Priority date: 2020-04-21
Filing date: 2020-04-21
Publication date: 2020-07-24
Anticipated expiration: 2040-04-21
Also published as: CN111442030B

Abstract

The invention discloses an air-flotation supporting system, wherein a piezoelectric ceramic ring is arranged above a supporting base, a conical stator is arranged above the piezoelectric ceramic ring, a shaft rotor is arranged at the upper end of the conical stator, a throttling hole is arranged in the middle of the conical stator, a shell is sleeved on the supporting base, a shaft hole and a positioning groove are arranged in the shell, a prismatic sleeve pasted with a rectangular piezoelectric sheet is placed in the positioning groove, a fastening end cover is arranged at the top of the shell, the shaft rotor passes through the shaft hole, the prismatic sleeve and the fastening end cover, a high-pressure air pipe passes through the base and the shell and respectively introduces high-pressure air to a gap of the conical stator and, according to the inverse piezoelectric effect, the piezoelectric material drives the prismatic sleeve wall and the conical stator to vibrate at high frequency to generate ultrasonic excitation to act on a high-pressure air film in the gap to generate mixed suspension force, and the axial and radial controllable suspension of the rotor is realized by changing air pressure and voltage parameters. The invention has simple driving structure, no abrasion and intelligent controllability. Is suitable for application in certain fields of high precision and no pollution.

Description

Air supporting system

Technical Field

The present invention relates to a bearing structure.

Background

The air-floating support system is also called as an air bearing. A sliding bearing using air as a lubricant. In normal operation, the shaft and bearing surfaces are completely separated by a gas film, whereby pressure changes in the film support the shaft and external loads. Because the air has smaller viscosity than oil, high temperature resistance and no pollution, the air bearing can be used in high-speed machines, instruments and radioactive devices, but the supporting system has small bearing capacity, low rigidity, poor stability, easy generation of air hammer phenomenon and the like, and has strict requirements on working conditions.

The acoustic levitation phenomenon was first discovered in 1866. This phenomenon is a nonlinear effect formed by the action of high intensity sound waves. The ultrasonic suspension is not limited by materials, and is mainly divided into ultrasonic standing wave suspension and near-field ultrasonic suspension according to different suspension working mechanisms. The ultrasonic standing wave suspension capability is poor, the bearing capacity is small, and the mass of the suspended object is required to be small. The near-field ultrasonic suspension with air as a medium has unique advantages: no additional effect on the suspended objects is generated; no special requirements on the electromagnetic property of the suspended object exist; simple structure and large suspension force.

The air floatation support and the near-field ultrasonic suspension are combined, the near-sound field suspension is added into the air floatation support system, the pressure of an air film can be redistributed, the cyclone and air hammer vibration phenomena when the traditional air floatation support system works alone are improved, the suspension rigidity is improved, and the micro low-frequency vibration existing in the air floatation device is reduced. The invention designs a novel air floatation support system, and ultrasonic suspension of a near sound field driven by a piezoelectric ceramic piece is added in the traditional air floatation support system. The extrusion state of the high-pressure air film is controlled by changing the voltage parameters, so that the air floatation support system forms precisely controllable suspension force, and the suspension state of the main shaft can be monitored. The suspension type hydraulic motor has the advantages of simple driving structure, large suspension force, no abrasion, flexible operation and wide application range.

Disclosure of Invention

The technical solution of the invention is realized as follows: an air supporting system is characterized in that: the boss is arranged above the inner part of the shell, and the boss with the shaft hole divides the inner part of the shell into an upper cavity and a lower cavity. The lower end of the shell is provided with a flanging; and a copper electrode iii, a piezoelectric ceramic ring ii, a copper electrode ii, a piezoelectric ceramic ring i, a copper electrode i and a conical stator are respectively stacked and fixed on the supporting base with the lower flange from bottom to top. A shaft rotor is arranged above the conical stator. The lower end of the shaft rotor is a conical concave surface and is matched with the conical convex surface of the conical stator. The flanges of the supporting base and the flanges of the shell are provided with through holes and fastened with each other through bolts. The center of the supporting base is provided with a base high-pressure air pipe hole, and the middle of the conical stator is provided with a stator throttling hole. A bottom high-pressure air pipe is arranged in the high-pressure air pipe hole of the base and is communicated into the stator throttling hole. Be equipped with prismatic sleeve in the upper chamber body, 3 positions that the outside of this prismatic sleeve was separated 120 each other all are equipped with prismatic gas pocket planes. The prismatic air hole plane is arranged in the prismatic sleeve circumferential positioning groove. Prismatic air vent plane is equipped with prismatic sleeve orifice. The prism sleeve outer plane is all equipped with prism sleeve outer plane in 3 positions of mutual interval 120 in the prism sleeve outside. The outer plane of the prism sleeve is pasted with a rectangular piezoelectric ceramic piece. The outer side of the upper part of the shell is provided with a shell air pipe hole, and the high-pressure air pipe passes through the shell air pipe hole and is communicated into the prismatic sleeve throttling hole. The top of the shell is provided with a fastening end cover. The shaft rotor passes through the shaft hole, the prismatic sleeve shaft hole and the fastening end cover. And radial gaps are arranged among the shaft rotor, the prismatic sleeve and the fastening end cover. The radial clearance ranges from 0.03mm to 0.05 mm. The optimum fit clearance is 0.04 mm. The outer side of the upper part of the shell is evenly distributed with piezoelectric ceramic piece wire holes at intervals of 120 degrees, and the lower part is provided with piezoelectric ceramic ring wire holes. The design gauge pressure ratio range of the prism sleeve throttling hole and the stator throttling hole is 0.35-0.60, the optimal design gauge pressure ratio is 0.45, the required air source pressure is 0.20-0.50 MPa, and the optimal air source pressure is 0.45 MPa; the diameter of the orifice ranges from 0.10mm to 0.30mm, and the optimal diameter of the orifice is 0.20 mm. The shell is in threaded connection with the fastening end cover.

By adopting the technical scheme, the air floatation supporting system provided by the invention can realize controllable and non-contact friction supporting of the shaft rotor through a simple structure. High-pressure gas is introduced for suspension, unstable phenomena such as air hammer, whirling and the like of the high-pressure gas can be inhibited by the extrusion effect generated by high-frequency vibration of the piezoelectric ceramic, the suspension force is further increased by the mixed action of the air flotation effect and the near-sound field ultrasonic suspension effect, the extrusion state and the suspension force of the high-pressure gas film are controlled by changing voltage parameters, the suspension state such as the eccentricity, the rotation precision and the like of the shaft rotor is regulated and controlled, and therefore the suspension state of the shaft rotor can be monitored. The driving structure is simple, no abrasion is caused, the operation is flexible, and the application range is wide.

Drawings

FIG. 1 is a perspective view of an air bearing support system.

FIG. 2 is a front view of an air bearing system.

FIG. 3 is a top view of an air bearing system.

Fig. 4 is a sectional view taken along line a-a of fig. 2.

Fig. 5 is an enlarged view of part i of fig. 4.

Fig. 6 is a partial enlarged view of ii of fig. 4.

Fig. 7 is a sectional view taken along line B-B of fig. 3.

Fig. 8 is a cross-sectional view taken along line D-D of fig. 3.

Fig. 9 is a sectional view of the C-C of fig. 4.

Fig. 10 is a perspective view of the housing structure.

Fig. 11 is a perspective half sectional view of the housing structure.

FIG. 12 is a perspective view of the internal structure of an air supporting system.

Fig. 13 is a perspective view of a prism sleeve.

FIG. 14 is a front view of a prismatic sleeve.

Fig. 15 is a cross-sectional view taken along line E-E of fig. 14.

In the figure: 1. a support base; 2-1, copper electrode i; 2-2 copper electrode ii; 2-3 copper electrode iii; 3. a conical stator; 4. a housing; 5. a shaft hole; 6. a prism sleeve circumferential positioning groove; 7. a prismatic sleeve; 8. a rectangular piezoelectric ceramic piece; 9. fastening an end cover; 10-1, a piezoelectric ceramic ring i; 10-2, a piezoelectric ceramic ring ii; 11. a wire hole of the piezoelectric ceramic sheet; 12. a piezoelectric ceramic ring wire hole; 13. a shaft rotor; 14. a bolt; 15. a high-pressure air pipe; 16. an upper cavity; 17. a shell gas duct aperture; 18. a prismatic sleeve orifice; 19. a base high pressure gas pipe hole; 20. a bottom high pressure gas pipe; 21. a stator orifice; 22. a radial gap; 23. an axial clearance; 24. A boss; 25. a prismatic pore plane; 26. a prismatic sleeve outer plane; 27, flanging; 28. a flange; 29. a lower cavity; 30. prismatic sleeve shaft hole.

Detailed Description

The attached drawing shows that the piezoelectric ceramic material is adopted to manufacture the radial and axial near-field ultrasonic suspension structure, and the rotor is stably supported in a non-contact manner in the radial and axial directions by the air floatation and near-field ultrasonic suspension mixed suspension mode.

An air supporting system is characterized in that: the upper part in the shell 4 is provided with a boss 24 with a shaft hole 5, the inside of the shell 4 is divided into two parts by the boss 24, the upper side of the boss 24 is provided with an upper cavity 16, and the lower side of the boss is provided with a lower cavity 29. The lower extreme of shell 4 is equipped with turn-ups 27, turn-ups 27 below is equipped with the support base 1 of taking flange 28, all be equipped with the through-hole on turn-ups 27 and the flange 28 and be in the same place through bolt 14 fixed coupling, the inner wall of going up cavity 16 is equipped with the prismatic sleeve circumference constant head tank 6 that the circumference angle split phase equals, the prismatic sleeve 7 outside is equipped with 3 prismatic air vent planes 25, the 6 quantity of sleeve circumference constant head tank that corresponds also is 3, prismatic air vent plane 25 can be placed in prismatic sleeve circumference constant head tank 6, play the circumference positioning effect to prismatic sleeve 7. The middle of the prismatic sleeve 7 is provided with a prismatic sleeve shaft hole 30 for accommodating the shaft rotor 13, the outer peripheral surface of the prismatic sleeve 7 is provided with a prismatic sleeve outer plane 26 at a position staggered with the prismatic air hole plane 25, the rectangular piezoelectric ceramic piece 8 is bonded and fixed on the prismatic sleeve outer plane 26 by using an adhesive, and the prismatic sleeve throttle hole 18 transversely penetrates through the prismatic sleeve 7 from the prismatic air hole plane 25 to the inner surface of the prismatic sleeve shaft hole 30. The outer side of the upper part of the shell 4 is provided with a shell air pipe hole 17, and the high-pressure air pipe 15 passes through the shell air pipe hole 17 and enters a prism sleeve throttling hole 18. The fastening end cover 9 provided with the central hole is connected to the shell 4 through threads, the top of the prismatic sleeve 7 is in contact with the fastening end cover 9, the prismatic sleeve 7 is fixed on the upper surface of the boss 24 through extrusion of the fastening end cover 9, and the fastening force can be adjusted by adjusting the screwing depth of the fastening end cover 9. The copper electrode iii-2-3, the piezoelectric ceramic ring ii-10-2, the copper electrode ii-2-2, the piezoelectric ceramic ring i-10-1, the copper electrode i-2-1 and the conical stator 3 with the conical convex surface at the upper part are adhered and fixed on the supporting base 1 by using an adhesive from bottom to top. The upper part of the conical stator 3 is a conical convex surface provided with a stator throttling hole 21, the lower end of the shaft rotor 13 is provided with a conical concave surface which is the same as the conical convex surface of the conical stator 3 in shape, the conical concave surface of the shaft rotor 13 is contacted with the conical convex surface of the conical stator 3 when the shaft rotor is not in operation, the shaft rotor and the conical concave surface are matched to form an axial gap 23 which can be dynamically changed when the shaft rotor and the conical concave surface are in normal operation, and the range of the axial gap 23 is 0.03 mm-0. The middle of the supporting base 1 is provided with a base high-pressure air pipe hole 19, the middle of the conical stator 3 is provided with a stator throttling hole 21, and the bottom high-pressure air pipe 20 penetrates through the base high-pressure air pipe hole 19 and is led into the stator throttling hole 21. The hollow shaft rotor 13 penetrates through the fastening end cover 9, the prismatic sleeve shaft hole 30 and the shaft hole 5 from top to bottom, a radial gap 22 is formed between the fastening end cover 9 and the prismatic sleeve shaft hole 30 and the shaft hole 5, the range of the radial gap 22 between the shaft rotor 13 and the prismatic sleeve 7 and between the shaft rotor 13 and the fastening end cover 9 is 0.03 mm-0.05 mm, and the optimal fit gap size is 0.04 mm. The design gauge pressure ratio range of the prism sleeve throttling hole and the stator throttling hole is 0.35-0.60, the optimal design gauge pressure ratio is 0.45, the diameter range of the throttling hole is 0.10-0.30 mm, the optimal diameter of the throttling hole is 0.20mm, the air source pressure required by high-pressure air is 0.20-0.50 Mpa, and the optimal air source pressure is 0.45 Mpa. The outer side of the upper part of the shell 4 is evenly distributed with piezoelectric ceramic piece wire holes 11, the lower part is evenly distributed with piezoelectric ceramic ring wire holes 12, and the wires are convenient to be connected with a high-frequency alternating current power supply for externally controlling the piezoelectric ceramics.

When in use, high-pressure gas is firstly introduced and then the power supply is switched on. High-pressure gas supplied by an external air pump penetrates through a shell air pipe hole 17 in the shell 4 through a high-pressure air pipe 15 to inject the high-pressure gas into the prism sleeve throttling hole 18, then the high-pressure gas passes through the prism sleeve throttling hole 18 at stable pressure, enters a radial gap 22 between the prism sleeve 7 and the shaft rotor 13 and acts on the suspended shaft rotor 13. At this time, a high-pressure film is formed between the shaft rotor 13 and the surface of the shaft hole 30 of the prism sleeve 7. The thickness of the high-pressure air film is equal to the radial gap, and the near-field ultrasonic suspension effect strength is higher when the thickness of the high-pressure air film is 0.03-0.05 mm. Three rectangular piezoelectric ceramic pieces 8 on the outer side of the prism sleeve 7 adopt the same polarization direction, and the rectangular piezoelectric ceramic pieces 8 can select and input the same voltage signal or different voltage signals according to the control requirement. According to the inverse piezoelectric effect, under the action of high-frequency alternating current voltage, the rectangular piezoelectric ceramic piece 8 is subjected to telescopic deformation in the length direction to drive the surface of the prismatic sleeve shaft hole 30 of the prismatic sleeve 7 to perform high-frequency oscillation, a high-pressure air film between the shaft rotor 13 and the prismatic sleeve 7 is extruded, the air flotation effect and the near-field ultrasonic suspension effect are coupled with each other, the suspension force is further increased, the air film can provide the radial suspension force, and the shaft rotor 13 can be stably suspended in the radial direction. Similarly, high-pressure gas enters the axial gap 23 between the conical concave surface of the shaft rotor 13 and the conical convex surface at the upper end of the conical stator 3 through the bottom high-pressure gas pipe 20 and the stator throttling hole 21, and the high-pressure gas forms a high-pressure gas film in the axial gap 23. According to the inverse piezoelectric effect, under the action of high-frequency alternating voltage, the piezoelectric ceramic ring i-10-1 and the piezoelectric ceramic ring ii-10-2 with opposite polarization directions stretch and deform along the thickness direction to drive the conical stator 3 to vibrate at high frequency, a high-pressure air film in the axial gap 23 is extruded, and the air flotation effect and the near-field ultrasonic suspension effect are coupled with each other to provide axial suspension force. The thickness of the air film can be dynamically changed along with the axial gap 23, the air supply pressure and the voltage parameters are controlled to enable the thickness of the air film to be in the range of 0.03 mm-0.05 mm, and at the moment, the near-field ultrasonic suspension effect is high in strength and large in suspension force.

The external load connected to the shaft rotor 13 during actual operation may not be constant in magnitude in the radial and axial directions of the shaft rotor 13. When the external load is changed, the air supply pressure is first changed to perform rough preliminary adjustment on the axial and radial suspension forces of the shaft rotor 13. Then alternating voltage signals on three rectangular piezoelectric ceramic plates 8 outside the prismatic sleeve 7 are respectively changed, different voltage parameters directly influence the deformation degree and the modal vibration mode of the prismatic sleeve 7, indirectly influence the extrusion effect of an air film, change the mixed suspension force generated by the air flotation effect and the near-field ultrasonic suspension effect, realize the accurate control of the radial suspension position of the shaft rotor 13, and regulate and control the suspension states of the shaft rotor 13 such as eccentricity, rotation precision and the like. Similarly, after the air supply pressure is adjusted in the axial direction, voltage signals applied to the piezoelectric ceramic rings i-10-1 and ii-10-2 are changed, the conical stator 3 generates different vibration amplitudes, the axial suspension force can be changed, and the accurate control of the axial suspension position of the shaft rotor 13 is realized.

In conclusion, the air floatation support system can realize controllable and friction-free suspension support of the rotor through a simple structure. The near-field ultrasonic suspension effect generated by the high-frequency vibration of the piezoelectric ceramic inhibits the unstable phenomena of air hammer, whirling and the like of the high-pressure gas while the high-pressure gas is introduced for suspension, and the bearing capacity generated by the combined action of the air flotation effect and the near-field ultrasonic suspension effect is greater than the sum of the bearing capacities of aerostatic suspension and near-field ultrasonic suspension when the two suspensions respectively and independently work. Therefore, compared with the traditional air floatation supporting system, the air floatation supporting system has higher suspension rigidity and can reduce the micro low-frequency vibration of the air static pressure suspension device. The mixed action of the air flotation effect and the near-field ultrasonic suspension effect can generate larger, more stable and controllable mixed suspension force. When the external load connected with the shaft rotor changes, the invention can control the extrusion state and the suspension force of the high-pressure air film in the radial direction and the axial direction of the rotor by changing the air pressure parameter and the voltage parameter of each piezoelectric ceramic, thereby realizing the accurate regulation and control of the suspension state of the rotor, such as the eccentricity, the rotation precision, the axial suspension height and the like, and further dynamically monitoring the running state of the shaft rotor. The driving structure is flexible to operate and wide in application range.

The above-mentioned embodiments only express the embodiments of the present invention, but not should be understood as the limitation of the scope of the invention patent, it should be noted that, for those skilled in the art, many variations and modifications can be made without departing from the concept of the present invention, and these all fall into the protection scope of the present invention.

Claims

1. An air supporting system is characterized in that: a boss (24) is arranged above the inner part of the shell (4), the boss (24) with the shaft hole (5) divides the inner part of the shell (4) into an upper cavity (16) and a lower cavity (29), and a flanging (27) is arranged at the lower end of the shell (4); a copper electrode iii (2-3), a piezoelectric ceramic ring ii (10-2), a copper electrode ii (2-2), a piezoelectric ceramic ring i (10-1), a copper electrode i (2-1) and a conical stator (3) are respectively stacked and mutually fixed on a supporting base (1) with a flange (28) arranged below from bottom to top, a shaft rotor (13) is arranged above the conical stator (3), the lower end of the shaft rotor (13) is a conical concave surface and is mutually matched with a conical convex surface of the conical stator (3); through holes are formed in the flange (28) of the supporting base (1) and the flanging (27) of the shell (4) and are fastened with each other through bolts (14); a base high-pressure air pipe hole (19) is formed in the center of the supporting base (1), a stator throttling hole (21) is formed in the middle of the conical stator (3), and a bottom high-pressure air pipe (20) is arranged in the base high-pressure air pipe hole (19) and is communicated into the stator throttling hole (21); a prism sleeve (7) is arranged in the upper cavity (16), prism air hole planes (25) are arranged at 3 positions of the outer side of the prism sleeve (7) which are spaced by 120 degrees, the prism air hole planes (25) are placed in the prism sleeve circumferential positioning grooves (6), and prism sleeve throttling holes (18) are formed in the prism air hole planes (25); 3 positions, which are spaced by 120 degrees from each other, on the outer side of the prism sleeve (7) are provided with prism sleeve outer planes (26), and rectangular piezoelectric ceramic plates (8) are attached to the prism sleeve outer planes (26); a shell air pipe hole (17) is formed in the outer side of the upper portion of the shell (4), and a high-pressure air pipe (15) penetrates through the shell air pipe hole (17) and is led into the prismatic sleeve throttling hole (18); a fastening end cover (9) is arranged at the top of the shell (4), the shaft rotor (13) penetrates through the shaft hole (5), the prismatic sleeve shaft hole (30) and the fastening end cover (9), and a radial gap (22) is formed between the shaft rotor (13) and the prismatic sleeve (7) as well as between the shaft rotor and the fastening end cover (9); piezoelectric ceramic piece wire holes (11) are uniformly distributed on the outer side of the upper part of the shell (4) at intervals of 120 degrees, and piezoelectric ceramic ring wire holes (12) are arranged on the lower part of the shell.

2. The air bearing support system of claim 1, wherein: the radial clearance (22) between the shaft rotor (13) and the prism sleeve (7) and between the shaft rotor and the fastening end cover (9) ranges from 0.03mm to 0.05 mm.

3. The air bearing support system of claim 2, wherein: the optimum fit clearance between the shaft rotor (13) and the prism sleeve (7) in the radial direction is 0.04 mm.

4. The air flotation support system according to claim 1, wherein the design gauge pressure ratio of the prism sleeve orifice (18) to the stator orifice (21) ranges from 0.35 to 0.60, the required air source pressure ranges from 0.20Mpa to 0.50Mpa, and the orifice diameter ranges from 0.10mm to 0.30 mm.

5. The air bearing support system as claimed in claim 4, wherein said prismatic sleeve orifice (18) and stator orifice (21) are designed to provide an optimum gauge pressure ratio of 0.45 and a desired air supply pressure of 0.45 Mpa.

6. The air bearing system as claimed in claim 4, wherein said orifice diameter is preferably 0.20 mm.

7. The air bearing support system of claim 1, wherein: the shell (4) is in threaded connection with the fastening end cover (9).