V-type Throttle Heavy-duty Hydrostatic Gas Bearing

Abstract

The present invention provides a V-type throttling heavy-duty hydrostatic gas bearing, belonging to the field of bearings, which includes an upper end cover and a lower support plate. A sealing ring is provided between the upper end cover and the lower support plate. An air cavity is provided on the side of the lower support plate close to the upper end cover. An air supply hole communicating with the air cavity is provided on the side surface of the lower support plate. A throttling hole communicating with the air cavity is provided at the lower end of the lower support plate. The throttling hole is vertically arranged. The throttling hole includes a large-diameter hole at the upper end and a small-diameter hole at the lower end. The small-diameter hole is a tapered structure with a gradually shrinking cross-section. The present invention ensures that the air flow realizes a smooth vector turn, making the flow inside the bearing from the throttling hole to the air film more stable, thereby improving the stability of the bearing.

Description

Technical Field

[0001] The present invention belongs to the field of bearings, relates to aerostatic bearings, and particularly relates to a V-type throttling heavy-duty hydrostatic aerostatic bearing. Background Art

[0002] With the rapid development of China's aerospace industry, large-scale and ultra-large-scale spacecraft micro-low gravity simulation tests are essential ground tests to ensure the performance and reliability of spacecraft.

[0003] As a key device in the process of spacecraft micro-gravity ground simulation tests, the performance of hydrostatic aerostatic bearings will directly affect the accuracy of ground tests. However, in view of the current development trend of larger and larger loads and higher and higher precision of large-scale and ultra-large-scale spacecraft, and the requirements for the load-bearing capacity of aerostatic bearings in ground tests are also getting higher and higher. Traditional hydrostatic aerostatic bearings are usually small-hole throttling aerostatic bearings. Its basic principle is that the air flow in the bearing flows out through the throttling holes, so that a layer of air film is formed between the bearing and the lower plane, thus making the bearing float. To improve the bearing capacity, the supply air pressure needs to be increased. However, as the supply air pressure increases, the flow velocity in the bearing throttling holes will increase sharply, and even complex phenomena such as supersonic flow and shock waves will occur. According to Bernoulli's principle, the greater the flow velocity of the gas, the more obvious the pressure drop. Excessive flow velocity will seriously affect the pressure in the air film, thus affecting the macroscopic load-bearing capacity.

[0004] Hydrostatic aerostatic bearings have the advantages of no friction, no pollution, high precision, low cost, etc., and are widely used in the fields of aerospace, electronic information, special processing, precision machinery, etc. However, the disadvantages of traditional aerostatic bearings such as small load-bearing capacity and low stiffness limit the development of gas bearings. Especially for precision machining and detection equipment, such as precision machine tools, precision measuring instruments, etc., higher requirements are placed on stiffness and stability.

[0005] According to gas dynamics, during the process of the air flow expanding and accelerating from a high-pressure and low-speed region, in the subsonic stage, as the flow channel area decreases, the air flow velocity increases. After the air flow reaches the speed of sound at the throat and enters the supersonic stage, the air flow velocity can continue to increase as the flow channel area increases. Therefore, when supersonic flow is required, the inner flow channel area is usually designed in the shape of a "flare" with a converging section - throat - diverging section.

[0006] For traditional hydrostatic gas bearings, they are usually orifice-throttled gas bearings. The basic principle is that the air flow inside the bearing flows out through the orifice, forming an air film between the bearing and the lower plane, so that the bearing floats. For the bearing load, the bearing load capacity F is formed by the integration of the air film pressure, which is orthogonal to the flow velocity V direction. That is, the greater the flow velocity, the smaller the pressure and the smaller the load capacity. Due to the internal orifice flow channel configuration of traditional gas bearings presenting a "funnel-like" shape, supersonic flow phenomena are extremely likely to occur at high supply pressures, thus affecting the bearing load performance. Summary of the Invention

[0007] The problem to be solved by the present invention is to provide a V-type throttled heavy-duty hydrostatic gas bearing. Under the condition of high supply pressure, there is no expansion section flow channel, ensuring that the air flow velocity cannot continue to increase, and it can well achieve the effect of reducing velocity and increasing pressure, thereby significantly improving the bearing load capacity.

[0008] To solve the above technical problems, the technical solution adopted by the present invention is: a V-type throttled heavy-duty hydrostatic gas bearing, including an upper end cover and a lower support plate. A sealing ring is provided between the upper end cover and the lower support plate. An air cavity is provided on the side of the lower support plate close to the upper end cover. An air supply hole communicating with the air cavity is provided on the side surface of the lower support plate. A throttling hole communicating with the air cavity is provided at the lower end of the lower support plate. The throttling hole is vertically arranged. The throttling hole includes a large-diameter hole at the upper end and a small-diameter hole at the lower end. The small-diameter hole is a tapered structure with a gradually shrinking cross-section.

[0009] Further, a plurality of the throttling holes are evenly distributed relative to the axis of the lower support plate, and the throttling holes can be evenly distributed in multiple circles.

[0010] Further, the minimum aperture of the small-diameter hole is 0.03 mm to 0.3 mm.

[0011] Further, the taper of the small-diameter hole is 60 to 90 degrees.

[0012] Further, the taper of the small-diameter hole is 70 to 80 degrees.

[0013] Further, the large-diameter hole and the small-diameter hole are coaxially arranged, and the large-diameter hole and the small-diameter hole are connected by a conical section. The taper of the conical section is 25 to 35 degrees.

[0014] Further, the diameter of the large-diameter hole is 2.8 to 3.6 times the maximum aperture of the small-diameter hole, and the length of the large-diameter hole is 4 to 6 times the length of the small-diameter hole.

[0015] Furthermore, an inlet hole is provided at the upper end of the large-diameter hole. The inlet hole is coaxially arranged with the large-diameter hole. The diameter of the inlet hole is 4 to 6 times that of the large-diameter hole, and the depth of the inlet hole is less than that of the large-diameter hole and greater than 85% of the depth of the large-diameter hole.

[0016] Furthermore, a lower flat plate is correspondingly arranged on the side of the lower support plate away from the upper end cover. After the air flows out through the throttle hole, an air film is formed between the lower flat plate and the lower support plate.

[0017] Furthermore, the V-shaped throttle type heavy-duty hydrostatic air bearing is a flat thrust bearing, an arc-shaped radial bearing or a spherical bearing.

[0018] Compared with the prior art, the advantages and positive effects of the present invention are as follows.

[0019] 1. The present invention is applicable to various types of air bearings such as flat surfaces and spherical surfaces. The throttle hole is provided with a large-diameter hole and a small-diameter hole from top to bottom, and the cross-sectional area gradually decreases, avoiding sudden expansion and change of the flow channel. During the outflow process of the medium, there is no expansion section in the flow channel, and the air flow velocity cannot continue to increase. The air flow can well achieve the effect of reducing speed and increasing pressure, so as to significantly improve the bearing capacity of the bearing.

[0020] 2. The present invention can be applied to equipment that requires high stiffness and high stability for air bearings, such as aerospace micro low-gravity simulation, ultra-high-precision test turntables, microelectronic equipment, high-precision machine tools, etc., and has good social effects and economic value.

[0021] 3. The minimum aperture of the small-diameter hole is 0.03 mm to 0.3 mm; preferably 0.15 to 0.2 mm; more preferably, the taper of the small-diameter hole is 60 to 90 degrees. Since the diameter of the small-diameter hole is very small, calculated in microns, the taper and aperture should be matched. The smaller the minimum diameter of the small-diameter hole, the larger its taper. For convenient processing and manufacturing, a larger drill bit is usually used to first process the large-diameter hole and finally process the small-diameter hole. Setting the above reasonable proportional parameters makes the throttle hole more convenient to manufacture, reduces costs, and ensures the stability of the air flow. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation to the present invention. In the drawings:

[0023] Figure 1 is a schematic structural diagram of the V-shaped throttle type heavy-duty hydrostatic air bearing of the present invention;

[0024] Figure 2 is a cross-sectional view of the throttle hole of the present invention;

[0025] Figure 3 This is an enlarged view of the small-diameter hole of the present invention.

[0026] Reference numerals:

[0027] 1. Upper end cover; 2. Lower support plate; 21. Air cavity; 3. Air supply hole; 4. Throttle hole; 41. Large-diameter hole; 42. Small-diameter hole; 43. Conical section; 44. Introduction hole; 5. Sealing ring; 6. Lower flat plate; 7. Air film. Detailed implementation manners

[0028] It should be noted that, without conflict, the embodiments in the present invention and the features in the embodiments may be combined with each other.

[0029] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention. In addition, the terms "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first", "second", etc. may explicitly or implicitly include one or more of such features. In the description of the present invention, unless otherwise specified, the meaning of "a plurality" is two or more.

[0030] In the description of the present invention, it should be noted that, unless otherwise clearly defined and limited, the terms "mounted", "connected", "coupled" should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the internal communication of two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood through specific situations.

[0031] The following will describe in detail the specific embodiments of the present invention with reference to the drawings.

[0032] As Figures 1 to 3As shown in the figure, the V-type throttling heavy-duty hydrostatic gas bearing includes an upper end cover 1 and a lower support plate 2. A sealing ring 5 is provided between the upper end cover 1 and the lower support plate 2. An air cavity 21 is provided on the side of the lower support plate 2 close to the upper end cover 1. An air supply hole 3 communicating with the air cavity 21 is provided on the side surface of the lower support plate 2. A throttling hole 4 communicating with the air cavity 21 is provided at the lower end of the lower support plate 2. The throttling hole 4 is vertically arranged. The throttling hole 4 includes a large-diameter hole 41 at the upper end and a small-diameter hole 42 at the lower end. The small-diameter hole 42 is a conical structure with a gradually shrinking cross-section.

[0033] Preferably, a plurality of throttling holes 4 are evenly distributed relative to the axis of the lower support plate 2. The throttling holes 4 can be evenly distributed in multiple circles. According to the load-bearing requirements, the number and layout of the throttling holes 4 are designed to meet the actual use needs. If the load-bearing capacity requirement is large, more throttling holes 4 need to be set to ensure more gas outflow and improve the load-bearing capacity. If the load-bearing capacity is small, fewer throttling holes 4 can be set. The arrangement of the throttling holes 4 does not require symmetry or other special setting requirements.

[0034] Preferably, the minimum aperture of the small-diameter hole 42 is 0.03 mm to 0.3 mm; preferably 0.15 to 0.2 mm; more preferably, the taper of the small-diameter hole 42 is 60 to 90 degrees. Since the diameter of the small-diameter hole 42 is very small, calculated in microns, the taper and aperture should match. The smaller the minimum diameter of the small-diameter hole 42, the larger its taper. For convenient processing and manufacturing, a larger drill bit is usually used to first process the large-diameter hole 41, and finally the small-diameter hole 42. Setting the above reasonable proportional parameters makes the throttling hole 4 more convenient to manufacture, reduces costs, and ensures the stability of the air flow.

[0035] Preferably, the taper of the small-diameter hole 42 is 70 to 80 degrees. Within this taper range, during the outflow process of the medium, there is no expanding section flow channel, and the air flow velocity cannot continue to increase. The air flow can well achieve the effect of reducing speed and increasing pressure, thereby significantly improving the bearing capacity of the bearing.

[0036] Preferably, the large-diameter hole 41 and the small-diameter hole 42 are coaxially arranged. The large-diameter hole 41 and the small-diameter hole 42 are connected by a conical section 43. The taper of the conical section 43 is 25 to 35 degrees. Setting a certain transition is more conducive to the transition and processing between the large-diameter hole 41 and the small-diameter hole 42. If the taper of the conical section 43 is too large, the structural layout of the small-diameter hole 42 is not conducive to setting. If the taper of the conical section 43 is too small, the transition is not smooth enough, which is not conducive to the stability of the air flow.

[0037] Preferably, the diameter of the large-diameter hole 41 is 2.8 to 3.6 times the maximum aperture of the small-diameter hole 42, and the length of the large-diameter hole 41 is 4 to 6 times the length of the small-diameter hole 42; more preferably, an inlet hole 44 is provided at the upper end of the large-diameter hole 41. The inlet hole 44 is coaxially arranged with the large-diameter hole 41. The diameter of the inlet hole 44 is 4 to 6 times the diameter of the large-diameter hole 41. The depth of the inlet hole 44 is less than the depth of the large-diameter hole 41 and greater than 85% of the depth of the large-diameter hole 41. The parameters set above better ensure the process of the flow channel gradually narrowing, avoid sudden expansion and change of the flow channel, better ensure the stability of the air flow velocity, further ensure the effect of reducing speed and increasing pressure, and improve the load-bearing capacity.

[0038] Preferably, a lower flat plate 6 is correspondingly arranged on the side of the lower support plate 2 away from the upper end cover 1. After the air flow is discharged through the throttle hole 4, an air film 7 is formed between the lower flat plate 6 and the lower support plate 2. The existence of the air film 7 forms an air floating layer, realizing the air floating principle.

[0039] Preferably, the V-type throttle heavy-duty hydrostatic air bearing is a flat thrust bearing, an arc radial bearing or a spherical bearing, with a wide range of applications.

[0040] During the actual use process, the air supply hole 3 is connected to an external air supply device, which can be nitrogen or ordinary gas, and is set according to the actual situation. The air cavity 21 is supplied with air through the air supply hole 3, and then the gas is ejected through the throttle hole 4 to form an air film 7, that is, an air floating layer, between the lower support plate 2 and the lower flat plate 6. Since the throttle hole 4 is sequentially provided with an inlet hole 44, a large-diameter hole 41 and a small-diameter hole 42 from top to bottom, and the cross-sectional area gradually decreases, sudden expansion and change of the flow channel are avoided. During the outflow process of the medium, there is no expansion section flow channel, and the air flow velocity cannot continue to increase. The air flow can well achieve the effect of reducing speed and increasing pressure, thereby significantly improving the load-bearing capacity of the bearing.

[0041] The above has described an embodiment of the present invention in detail, but the content described is only a preferred embodiment of the present invention and cannot be considered as limiting the scope of implementation of the present invention. All equivalent changes and improvements made according to the scope of the application of the present invention should still fall within the scope covered by the patent of the present invention.

Claims

1. V-type throttling heavy-duty hydrostatic gas bearing, applied to sudden expansion and change of flow channels. During the process of medium outflow, there is no expansion section in the flow channel, and the air flow velocity cannot continue to increase. In the case of air flow deceleration and pressure increase, it is characterized in that: It includes an upper end cover and a lower support plate. A sealing ring is provided between the upper end cover and the lower support plate. An air cavity is provided on one side of the lower support plate close to the upper end cover. An air supply hole communicating with the air cavity is provided on the side surface of the lower support plate. A throttle hole communicating with the air cavity is provided at the lower end of the lower support plate. The throttle hole is vertically arranged. The throttle hole includes a large-diameter hole at the upper end and a small-diameter hole at the lower end. The small-diameter hole is a tapered structure with a gradually shrinking cross-section. The minimum aperture of the small-diameter hole is 0.15 mm to 0.2 mm. The taper of the small-diameter hole is 70 to 80 degrees, without increasing the air flow velocity, so as to achieve speed reduction and pressure increase and increase the bearing capacity of the bearing. The large-diameter hole and the small-diameter hole are coaxially arranged. The large-diameter hole and the small-diameter hole are connected by a conical section. The taper of the conical section is 25 to 35 degrees. The diameter of the large-diameter hole is 2.8 to 3.6 times the maximum aperture of the small-diameter hole. The length of the large-diameter hole is 4 to 6 times the length of the small-diameter hole. An inlet hole is provided at the upper end of the large-diameter hole. The inlet hole is coaxially arranged with the large-diameter hole. The diameter of the inlet hole is 4 to 6 times the diameter of the large-diameter hole. The depth of the inlet hole is less than the depth of the large-diameter hole and greater than 85% of the depth of the large-diameter hole. The throttle holes are arranged in a plurality of circumferential arrays relative to the axis of the lower support plate, and the throttle holes can be arranged in multiple circumferential arrays. A lower flat plate is correspondingly arranged on the side of the lower support plate away from the upper end cover. After the air flow passes through the throttle holes and is discharged, an air film is formed between the lower flat plate and the lower support plate.

2. The V-type throttling heavy-duty hydrostatic gas bearing according to claim 1, characterized in that: The V-shaped throttle type heavy-duty hydrostatic air bearing is a flat thrust bearing, an arc radial bearing or a spherical bearing.

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