CN101691879A - Dynamic and static pressure composite gas bearing with internal pi shaped air wedge groove - Google Patents

Abstract

The invention relates to an inner π-shaped air wedge groove dynamic and static pressure composite air bearing, which relates to the bearing technology and is an air bearing with a new structure for supporting ultra-high-speed rotating machines. Its structural feature is that the inner surface of the bearing adopts the design of π-shaped air wedge groove, the composite design of dynamic and static pressure, and the design of dynamic and static pressure on the thrust surface. air supply hole. The air bearing of the present invention avoids the disadvantages of coupling and mutual interference between static pressure and dynamic pressure, avoids the disadvantages of inconsistent dynamic pressure effects at both ends of the bearing, not only significantly improves the bearing capacity and rotational speed of the bearing, but also greatly reduces The axial and lateral vibration of the rotor journal improves the stability and reliability of the rotor system. Therefore, the present invention has the advantages of simple structure, high bearing capacity, stable operation and high reliability, and further broadens the application range of the air bearing.

Description

Inner π-shaped air wedge groove dynamic and static pressure composite air bearing

technical field

The invention belongs to the technical field of bearings, and relates to an inner π-shaped air wedge groove dynamic and static pressure composite air bearing for supporting high-speed rotating machines.

Background technique

Air bearing is a high-tech product developed rapidly in the middle of the 20th century. Compared with traditional rolling bearings or oily sliding bearings, it has high speed, high precision, low power consumption, no pollution, long life, and environmental adaptability. Strong and other advantages. Therefore, it is widely used in national defense, energy, machine tools and medical industries, especially in the fields of ultra-high-speed rotating machinery and ultra-precision instrument technology.

At present, there are two basic lubrication methods for air bearing lubrication, one is static pressure air bearing, as shown in Figure 1; the other is dynamic pressure air bearing or dynamic and static pressure hybrid air bearing. The dynamic pressure air bearing can be divided into two ways, one is to slot on the rotor supported by the air bearing, and the other is to slot on the inner surface of the air bearing; Figure 2 is an axial flow groove type dynamic pressure air bearing. The sectional view of the floating bearing, in the figure, the rotor journal 1, the bearing body 2, the supercharging channel groove 3 and the elastic ring 4 on the outer surface of the rotor journal 1, the supercharging channel slot is herringbone; patent application: π-shaped Groove dynamic and static pressure hybrid gas bearing, application number 94207681.8, as shown in Figure 3, its core is to open a π-shaped booster flow channel groove on the rotor journal.

Whether it is a static pressure air bearing or a dynamic pressure air bearing, the principle is to rely on gas lubrication. The bearing is a bearing that uses the viscosity of the gas to increase the gas pressure in the gap, thereby suspending the shaft (see [Japan] Shihe Shinichi Author, translated by Han Huanchen "Design, Manufacture and Application of Pneumatic Bearings", Yuhang Press, 1988). The axial flow groove type dynamic pressure air bearing is processed into an airflow channel on the surface of the journal, and the relative moving surface with a wedge-shaped dynamic and static gap gradually becomes smaller along the moving direction. The viscous effect of the gas is used to drag on the relatively moving wedge-shaped surface. The pressure makes the shaft suspend (see [Su] B.H Delozedovic, translated by Zheng Lizhu, "Dynamic Pressure Air Bearing", National Defense Industry Press, 1982); the advantage of the above-mentioned static pressure and dynamic pressure air bearings is that the structure is simple , is easy to maintain, and is also very effective in many cases; however, the bearing capacity of the static pressure air bearing is low, and the weight of the rotating body to be supported cannot be too high; The structural characteristics of the bearings all have high requirements on the wear resistance of the contact surface in short periods of time such as start and stop, and the rough surface of the journal is more likely to cause rubbing and wear of moving and static parts, resulting in bearing failure.

Patent application: inner channel self-lubricating dynamic and static pressure coupling air bearing, application number: 200720177830.7, see Figure 4A and Figure 4B. As shown, its main contents are as follows: it consists of rotor journal 1, bearing body 2, booster runner groove 3, damping elastic ring 4, air supply hole 5, and air supply nozzle 6; air supply hole 5 and air supply nozzle 6 It constitutes a static pressure system, and the pressurized runner groove is a dynamic pressure system. There are two main problems: one is that the air supply nozzle 6 of the static pressure system is located in the pressurized channel groove 3 of the dynamic pressure system. When the air supply of the static pressure system is uneven or the rotor vibrates, the air supply nozzle 6 comes in The flow field formed by the air is disturbed, and the support stiffness at both ends of the bearing is no longer equal, which will cause excessive vibration or instability of the high-speed rotating machinery; the second is that the two pressurized flow channel grooves at both ends of the bearing of the dynamic pressure system are not connected, and in the rotor In the case of vibration or unequal static air supply pressure, the dynamic pressure effect at both ends of the bearing is no longer equal, thereby reducing the bearing capacity of the air bearing, that is, reducing the reliability of high-speed rotating machinery.

Patent application: Dynamic pressure air bearing with inner channel self-lubricating structure, application number: 200720177829.4, as shown in Figure 5A and Figure 5B, the main content is as follows: It consists of rotor journal 1, bearing body 2, pressurized channel groove 3. The elastic ring is composed of 4; there are two main problems: one is that because it is a pure dynamic pressure air bearing, the dynamic pressure effect of the air bearing is poor during the start-up phase and the low-speed phase (such as below 20,000 rpm). , the journal cannot be effectively floated, and the bearing is not lubricated smoothly, resulting in severe short-term rubbing and vibration; second, the two pressurized runner grooves at both ends of the bearing are not connected, and the rotor vibrates or local rubbing or external disturbances , the dynamic pressure effect at both ends of the bearing is no longer equal, thus reducing the bearing capacity of the dynamic pressure air bearing, that is, reducing the reliability of high-speed rotating machinery.

Contents of the invention

The technical problem to be solved in the present invention is to propose an inner π-shaped air wedge groove dynamic and static pressure composite air bearing, which overcomes the shortcomings of the above-mentioned existing static pressure air bearing, dynamic pressure air bearing and dynamic and static pressure coupled air bearing .

An inner π-shaped air wedge groove dynamic and static pressure composite air bearing, the composite, one means that the bearing is composed of a static pressure system and a dynamic pressure system, and the other means that the bearing has both radial and axial (thrust) supporting capabilities .

For achieving the above object, technical solution of the present invention is:

The static pressure system is to set through static pressure air supply holes on the thrust surface and inner surface of the bearing respectively, including the static pressure air inlet on the thrust surface, the static pressure vertical nozzle on the thrust surface, the static pressure air supply hole on the inner surface and the static pressure air supply hole on the inner surface. Pressure tangential nozzles; thrust surface static pressure vertical nozzle direction is perpendicular to the thrust surface, there are two rows of nozzles, each row is centrally symmetrical and evenly distributed along the center of the thrust surface; there is a row of static pressure tangential nozzles on the inner surface, the nozzle direction Tangentially intersects the inner surface of the bearing.

The dynamic pressure system includes a dynamic pressure spiral groove on the thrust surface and a dynamic pressure π-shaped air wedge groove on the inner surface; the depth of the dynamic pressure spiral groove on the thrust surface is the same, the top has a sharp angle, and the interval between the thrust surface and the static pressure nozzle on the thrust surface is Evenly distributed; inner surface dynamic pressure π-shaped air wedge groove, its shape is π-shaped, the groove width is uniform, and there is an air wedge angle, that is, the depth of the groove along the direction of rotation changes from deep to shallow, and the π-line groove is static along the inner surface The pressure nozzles are evenly spaced.

The radial support is composed of a static pressure system and a dynamic pressure system on the inner surface of the bearing, and the thrust is composed of a static pressure system and a dynamic pressure system on the thrust surface of the bearing.

The beneficial effect of the present invention is that the inner surface of the bearing adopts the design of π-shaped air wedge groove, the design of dynamic and static pressure mixing and the design of dynamic and static pressure on the thrust surface, which improves the bearing capacity of the bearing in the low-speed and high-speed stages, and the design of the through-shaped π-shaped air wedge groove is effective The stability and reliability of the support are improved; the thrust surface can greatly reduce the axial vibration of the supported journal, further expanding the application range of the air bearing.

Description of drawings

Fig. 1 is a structural schematic diagram of an existing static pressure air bearing.

Fig. 2 is a schematic diagram of an existing axial flow groove type dynamic pressure air bearing.

Fig. 3 is a structural schematic diagram of the existing π-shaped groove dynamic and static pressure hybrid gas bearing.

Fig. 4A is a schematic structural diagram of a conventional internal channel self-lubricating dynamic and static pressure coupling air bearing.

Fig. 4B is a schematic diagram of the structure of the pressurized runner groove on the inner surface of the air bearing shown in Fig. 4A.

Fig. 5A is a structural schematic diagram of a dynamic pressure air bearing with a self-lubricating inner channel structure.

Fig. 5B is a schematic diagram of the structure of the pressurized runner groove on the inner surface of the air bearing shown in Fig. 5A.

Fig. 6 is a schematic cross-sectional view of the inner π-shaped air wedge groove dynamic and static pressure composite air bearing of the present invention.

Fig. 7 is a schematic diagram of the thrust surface of Fig. 6 .

FIG. 8 is a schematic longitudinal sectional view of FIG. 6 .

Fig. 9A, Fig. 9B and Fig. 9C are schematic diagrams of the shape and depth of the π-shaped air wedge groove on the inner surface of the bearing.

In the figure: 01 static pressure air supply hole on the thrust surface; 02 static pressure air supply hole on the inner surface; 03 static pressure vertical nozzle on the thrust surface; 04 static pressure tangential nozzle on the inner surface; 05 dynamic pressure π-shaped air wedge groove on the inner surface; 06 thrust surface dynamic pressure spiral groove 07 sealing ring.

Detailed ways

Embodiments are described in detail below in conjunction with technologies and accompanying drawings.

As shown in the figure, the inner π-shaped air wedge groove dynamic and static pressure composite air bearing of the present invention is composed of the static pressure air supply hole 01 on the thrust surface, the static pressure air supply hole 02 on the inner surface, the static pressure vertical nozzle 03 on the thrust surface, the inner surface It consists of static pressure tangential nozzle 04, inner surface dynamic pressure π-shaped air wedge groove 05, thrust surface dynamic pressure spiral groove 06, and sealing ring 07. The inner π-shaped air wedge groove dynamic and static pressure composite air bearing mainly provides support stiffness for the rotor journal through the static pressure system and the dynamic pressure system, among which,

The static pressure system includes thrust surface static pressure inlet hole 01, thrust surface static pressure vertical nozzle 03, inner surface static pressure air supply hole 02, inner surface static pressure tangential nozzle composition 04; thrust surface static pressure vertical nozzle The direction of 03 is perpendicular to the thrust surface. There are two rows of nozzles, and each row is distributed symmetrically and evenly along the center of the thrust surface; there is a row of static pressure tangential nozzles 04 on the inner surface, which are respectively located on the inner surface of the dynamic pressure π-shaped air wedge groove 05. , the direction of the nozzle intersects tangentially with the inner surface of the bearing.

The dynamic pressure system includes the dynamic pressure spiral groove 06 on the thrust surface, and the dynamic pressure π-shaped air wedge groove 05 on the inner surface; The pressure nozzles are evenly spaced; the dynamic pressure π-shaped air wedge groove 05 on the inner surface is π-shaped, the groove width is uniform, and there is an air wedge angle, that is, the depth of the groove changes from deep to shallow along the direction of rotation. The π-shaped grooves are evenly distributed along the inner surface and spaced from the static pressure nozzle on the inner surface.

At the same time, please refer to the accompanying drawings, the core technology of the present invention is to adopt the π-shaped air wedge groove design, the dynamic and static pressure hybrid design and the thrust face dynamic and static pressure design. The principle is based on the structural characteristics of the air bearing and the static and dynamic parts of the supported rotor journal. First, the static pressure system is used to suspend the rotor journal on the inner surface of the bearing and the thrust surface, and for the rotor journal within a certain speed range. The rotation provides support stiffness and damping; when the rotational speed of the rotor journal increases to a certain level, the dynamic pressure system begins to exert greater support stiffness, that is, the dynamic pressure spiral groove 06 on the thrust surface and the π-shaped air wedge on the inner surface The air in the slot 05 is driven by the high-speed rotating rotor journal to form the effect of gas pressurization. In addition to the function of sealing high-pressure gas, the sealing ring 07 can also reduce the friction and wear of the air bearing during the start-up stage of the supported rotor.

The composite design of dynamic pressure and static pressure of the air bearing can provide the support stiffness for the rotor journal in the process of rotating from low speed to high speed, avoiding the coupling and mutual interference between static pressure and dynamic pressure; the through π-shaped The design of the air wedge groove can avoid the serious disadvantage of inconsistent dynamic pressure effect at both ends of the "eight" or "herringbone" shape pressurized runner groove (or dynamic pressure groove). Consistent, making the rotor journal run more stable and reliable. The dynamic and static pressure design of the thrust surface can make the rotor journal suspended between the two bearings, which acts as a thrust bearing, greatly reduces the axial vibration of the rotor journal, and at the same time has a good suppression effect on radial vibration , Therefore, the stability of the rotor journal operation is significantly improved, and the application range of the air bearing is broadened.

Claims (1)

1. π shape gas wedge groove dynamic and static pressure composite air-bearing in a kind comprises thrust surface static pressure air vent (01), internal surface static pressure air vent (02), the vertical nozzle of thrust surface static pressure (03), internal surface static pressure tangential nozzle (04), internal surface dynamic pressure π shape gas wedge groove (05), thrust surface dynamic pressure spiral chute (06) and seal ring (07); It is characterized in that: comprise static-pressure system and dynamic pressure system, wherein,

Static-pressure system is to offer the static pressure air vent of perforation respectively at bearing thrust face and internal surface, and the vertical nozzle of thrust surface static pressure (03) direction is vertical with thrust surface, and nozzle has two rows, and every row is centrosymmetric along the thrust surface center and evenly distributes; Internal surface static pressure tangential nozzle (04) has a row, lays respectively between the internal surface dynamic pressure π shape gas wedge groove (05), and nozzle direction and bearing inner surface are tangential and intersect;

The dynamic pressure system offers dynamic pressure spiral chute (06), internal surface dynamic pressure π shape gas wedge groove (05) respectively at bearing thrust face and internal surface; Thrust surface dynamic pressure spiral chute (06) degree of depth unanimity, the top has wedge angle, evenly distributes at interval along thrust surface and thrust surface static pressure nozzle; Internal surface dynamic pressure π shape gas wedge groove (05);

Groove be shaped as π shape, groove width is even, and the gas angle of wedge is arranged, along the degree of depth of sense of rotation groove from depth to shallow promptly.π shape gas wedge groove (05) evenly distributes along the whole circle of internal surface, and spaced apart with internal surface static pressure nozzle.

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