CN111442030B

CN111442030B - Air supporting system

Info

Publication number: CN111442030B
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: 2024-04-26
Anticipated expiration: 2040-04-21
Also published as: CN111442030A

Abstract

The invention discloses an air-floating support system, wherein a piezoelectric ceramic ring is arranged above a support base, a conical stator is arranged above the piezoelectric ceramic ring, a shaft rotor is arranged at the upper end of the conical stator, an orifice is arranged in the middle of the conical stator, a shell is sleeved on the support 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 penetrates through the shaft hole, the prismatic sleeve and the fastening end cover, a high-pressure air pipe penetrates through the base and the shell to respectively introduce high-pressure air into radial gaps of the conical stator and the prismatic sleeve to form a high-pressure air film, piezoelectric materials drive the cylindrical wall and the conical stator to vibrate at high frequency to generate ultrasonic excitation to act on the high-pressure air film in the gaps according to the inverse piezoelectric effect, mixed suspension force is generated, and 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 and controllable performance. Is suitable for certain high-precision pollution-free fields.

Description

Air supporting system

Technical Field

The present invention relates to a bearing structure.

Background

The air bearing system is also called a gas bearing. A sliding bearing using air as a lubricant. In normal operation, the shaft and bearing surfaces are completely separated by a gas film, supporting the shaft and external force load by virtue of pressure changes in the gas film. Because the air is less viscous than oil, high temperature resistant and pollution free, 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.

Acoustic suspension was found earliest in 1866. This phenomenon is a nonlinear effect created by the action of high intensity sound waves. Ultrasonic levitation is not limited by materials, and is mainly divided into ultrasonic standing wave levitation and near-field ultrasonic levitation according to different levitation working mechanisms. The ultrasonic standing wave has poor suspending capability and small bearing capability, and the mass of the object to be suspended is small. While near-field ultrasound levitation with air as a medium has unique advantages: no additional effect is produced on the suspended object; no special electromagnetic requirements are imposed on the suspended bodies; simple structure and larger suspension force.

The air floatation support and the near-field ultrasonic suspension are combined, and the near-field sound field suspension is added into the air floatation support system, so that the air film pressure can be redistributed, the cyclone and air hammer vibration phenomena of the traditional air floatation support system during independent working are improved, the suspension rigidity is improved, and the tiny low-frequency vibration of the air floatation device is reduced. The invention designs a novel air floatation supporting system, wherein ultrasonic suspension of a near sound field driven by a piezoelectric ceramic plate is added into a traditional air floatation supporting system. The high-pressure air film extrusion state is controlled by changing the voltage parameter, so that the air floatation support system forms accurately controllable suspension force, and the suspension state of the main shaft can be monitored. The device 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, characterized in that: a boss is arranged above the inside of the shell, and the boss provided with a shaft hole divides the inside of the shell into an upper cavity and a lower cavity. The lower end of the shell is provided with a flanging; copper electrodes iii, piezoelectric ceramic rings ii, copper electrodes ii, piezoelectric ceramic rings i, copper electrodes i and conical stators are respectively stacked and mutually fixed on a support base with a flange at the lower part 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 flange of the support base and the flanging of the shell are respectively provided with a through hole and are mutually fastened through bolts. The center of the supporting base is provided with a base high-pressure air pipe hole, and a stator orifice is arranged in the middle of the conical stator. The high-pressure air pipe hole of the base is internally provided with a bottom high-pressure air pipe which is led into the stator orifice. The upper cavity is internally provided with a prismatic sleeve, and 3 positions, which are mutually separated by 120 degrees, of the outer side of the prismatic sleeve are respectively provided with a prismatic air hole plane. The prism air hole plane is placed in the prism sleeve circumferential positioning groove. The prism air hole plane is provided with a prism sleeve orifice. The outer sides of the prismatic sleeves are respectively provided with an outer plane of the prismatic sleeve at 3 positions which are mutually separated by 120 degrees. Rectangular piezoelectric ceramic plates are stuck on the outer plane of the prismatic sleeve. 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 led into the orifice of the prismatic sleeve. 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. A radial gap is arranged between the shaft rotor and the prismatic sleeve and between the shaft rotor and the fastening end cover. The radial clearance ranges from 0.03mm to 0.05mm. The optimal fit clearance is 0.04mm. The outer side of the upper part of the shell is uniformly distributed with piezoelectric ceramic plate wire guide holes at 120 degrees intervals, and the lower part of the shell is provided with piezoelectric ceramic ring wire guide holes. The design gauge pressure ratio range of the prism sleeve orifice and the stator orifice 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 0.45Mpa; the diameter of the orifice ranges from 0.10mm to 0.30mm, and the diameter of the optimal orifice is 0.20mm. 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. The high-pressure gas is introduced to suspend, the extrusion effect generated by the high-frequency vibration of the piezoelectric ceramic can inhibit unstable phenomena such as air hammer and whirling of the high-pressure gas, the air floatation effect and the near-sound field ultrasonic suspension effect are mixed, the suspension force is further increased, the extrusion state and the suspension force of the high-pressure gas film are controlled by changing voltage parameters, the eccentricity of the shaft rotor, the suspension state such as rotation precision and the like are regulated, and accordingly the suspension state of the shaft rotor can be monitored. The driving structure is simple, the abrasion is avoided, the operation is flexible, and the application range is wide.

Drawings

Fig. 1 is a perspective view of an air bearing 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 cross-sectional view of section A-A of fig. 2.

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

Fig. 6 is an enlarged view of part ii of fig. 4.

Fig. 7 is a sectional view of section B-B of fig. 3.

Fig. 8 is a sectional view of the D-D section of fig. 3.

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

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

Fig. 11 is a perspective and semi-sectional view of the housing structure.

Fig. 12 is a perspective view of an internal structure of an air bearing system.

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

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

Fig. 15 is a sectional view of the E-E section 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 tapered stator; 4. a housing; 5. a shaft hole; 6. a prismatic sleeve circumferential positioning groove; 7. a prismatic sleeve; 8. rectangular piezoelectric ceramic plates; 9. fastening the end cover; 10-1, piezoelectric ceramic ring i;10-2, piezoelectric ceramic ring ii; 11. a piezoelectric ceramic piece wire guide; 12. a piezoelectric ceramic ring wire guide; 13. a shaft rotor; 14. a bolt; 15. a high pressure gas pipe; 16. an upper cavity; 17. a housing gas tube aperture; 18. prismatic sleeve orifice; 19. a base high-pressure air pipe hole; 20. a bottom high pressure gas pipe; 21. a stator orifice; 22. radial clearance; 23. an axial gap; 24. A boss; 25. prismatic vent planes; 26. the outer plane of the prismatic sleeve; 27 flanging; 28. a flange; 29. a lower cavity; 30. and the prism sleeve shaft hole.

Detailed Description

The drawing shows that the invention adopts the piezoelectric ceramic material to manufacture the radial and axial near-field ultrasonic levitation structure, and realizes the radial and axial non-contact stable support of the rotor by the mode of air floatation and near-field ultrasonic levitation mixed levitation.

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

When in use, high-pressure gas is firstly introduced and then the power supply is switched on. The high-pressure gas supplied by the external air pump is injected into the prismatic sleeve orifice 18 through the casing air pipe hole 17 on the casing 4 by the high-pressure air pipe 15, then passes through the prismatic sleeve orifice 18 with stable pressure, and then enters the radial gap 22 between the prismatic sleeve 7 and the shaft rotor 13 to act on the suspended shaft rotor 13. A high pressure gas 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 intensity of the near-field ultrasonic suspension effect is larger when the thickness is 0.03 mm-0.05 mm. The three rectangular piezoelectric ceramic plates 8 on the outer side of the prismatic sleeve 7 adopt the same polarization direction, and the rectangular piezoelectric ceramic plates 8 can selectively input the same voltage signals or different voltage signals according to control requirements. According to the inverse piezoelectric effect, under the action of high-frequency alternating voltage, the rectangular piezoelectric ceramic plate 8 stretches and deforms in the length direction, the surface of the prism sleeve shaft hole 30 of the prism sleeve 7 is driven to oscillate in a high frequency manner, a high-pressure air film between the shaft rotor 13 and the prism sleeve 7 is extruded, the air floatation effect and the near-field ultrasonic suspension effect are mutually coupled, the suspension force is further increased, and the air film can provide the suspension force in the radial direction, so that the shaft rotor 13 can stably suspend 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 of the upper end of the conical stator 3 through the bottom high-pressure gas pipe 20 and the stator orifice 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 rings i-10-1 and 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 floatation effect and the near-field ultrasonic suspension effect are mutually coupled to provide axial suspension force. The thickness of the air film can be dynamically changed along with the axial gap 23, and 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, so that the intensity of the near-field ultrasonic suspension effect is high, and the suspension force is high.

The external load to which the shaft rotor 13 is connected during actual operation may not be constant in the radial and axial dimensions of the shaft rotor 13. When the external load is changed, the air supply pressure is changed first to make rough preliminary adjustment of the axial and radial levitation force of the shaft rotor 13. Then respectively changing alternating current voltage signals on three rectangular piezoelectric ceramic plates 8 on the outer side of the prismatic sleeve 7, wherein different voltage parameters directly influence the deformation degree and the mode vibration mode of the prismatic sleeve 7, indirectly influence the extrusion effect of an air film, change the mixed levitation force generated by the air floatation effect and the near-field ultrasonic levitation effect, realize the accurate control of the radial levitation position of the shaft rotor 13, and regulate and control the levitation states such as the eccentricity, the rotation precision and the like of the shaft rotor 13. 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 levitation force can be changed, and the accurate control of the axial levitation position of the shaft rotor 13 is realized.

In summary, the air bearing system of the invention can realize controllable friction-free suspension support of the rotor through a simple structure. The near-field ultrasonic levitation effect generated by the high-frequency vibration of the piezoelectric ceramic suppresses unstable phenomena such as air hammer and whirling of the high-pressure gas while the high-pressure gas is introduced for levitation, and the bearing capacity generated by the combined action of the air levitation effect and the near-field ultrasonic levitation effect is larger than the sum of the bearing capacities of the air static pressure levitation and the near-field ultrasonic levitation when the two levitation respectively and independently work. Compared with the traditional air floatation supporting system, the air floatation supporting system has higher suspension rigidity and can reduce the tiny low-frequency vibration existing in the air floatation device. The mixing effect of the air floatation effect and the near-field ultrasonic floatation effect can generate larger, more stable and controllable mixed floatation 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 precise regulation and control of the suspension state such as the eccentricity, the rotation precision, the axial suspension height and the like of the rotor, and further dynamically monitoring the running state of the shaft rotor. The driving structure is flexible in operation and wide in application range.

The examples described above represent only embodiments of the invention and are not to be understood as limiting the scope of the patent of the invention, it being pointed out that several variants and modifications may be made by those skilled in the art without departing from the concept of the invention, which fall within the scope of protection of the invention.

Claims

1. An air supporting system, characterized in that: a boss (24) is arranged above the inside of the shell (4), the boss (24) provided with a shaft hole (5) divides the inside 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); copper electrodes iii (2-3), piezoelectric ceramic rings ii (10-2), copper electrodes ii (2-2), piezoelectric ceramic rings i (10-1), copper electrodes i (2-1) and conical stators (3) are respectively stacked and mutually fixed on a support base (1) with a flange (28) at the lower part from bottom to top, a shaft rotor (13) is arranged above the conical stators (3), and the lower ends of the shaft rotor (13) are conical concave surfaces and are mutually matched with the conical convex surfaces of the conical stators (3); the flange (28) of the supporting base (1) and the flanging (27) of the shell (4) are respectively provided with a through hole and are mutually fastened through bolts (14); the center of the supporting base (1) is provided with a base high-pressure air pipe hole (19), a stator orifice (21) is arranged 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 led into the stator orifice (21); a prism sleeve (7) is arranged in the upper cavity (16), prism air hole planes (25) are arranged at 3 positions, which are mutually separated by 120 degrees, on the outer side of the prism sleeve (7), the prism air hole planes (25) are placed in a prism sleeve circumferential positioning groove (6), and the prism air hole planes (25) are provided with prism sleeve throttling holes (18); the outer sides of the prismatic sleeves (7) are respectively provided with prismatic sleeve outer planes (26) at 3 positions which are mutually separated by 120 degrees, and the prismatic sleeve outer planes (26) are stuck with rectangular piezoelectric ceramic plates (8); the outer side of the upper part of the shell (4) is provided with a shell air pipe hole (17), and a high-pressure air pipe (15) passes through the shell air pipe hole (17) and is led into the prismatic sleeve orifice (18); the top of the shell (4) is provided with a fastening end cover (9), 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 clearance (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); the outer side of the upper part of the shell (4) is uniformly distributed with piezoelectric ceramic sheet wire guide holes (11) at intervals of 120 degrees, and the lower part of the shell is provided with piezoelectric ceramic ring wire guide holes (12);

The surface pressure ratio range of the prismatic sleeve throttle hole (18) and the stator throttle hole (21) is designed to be 0.35-0.60, the required air source pressure is 0.20-0.50 Mpa, and the diameter range of the throttle hole is 0.10-0.30 mm;

The shell (4) is in threaded connection with the fastening end cover (9).

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

3. An air bearing support system according to claim 2, wherein: the fit clearance between the shaft rotor (13) and the prismatic sleeve (7) in the radial direction is 0.04mm.

4. An air bearing system according to any of claims 1-3, wherein the prismatic sleeve orifice (18) and the stator orifice (21) are designed to have a gauge ratio of 0.45 and the required air supply pressure is 0.45Mpa.

5. An air bearing system according to any one of claims 1 to 3, said orifice diameter being 0.20mm.