An in-line flow restriction device

Abstract

The application discloses an embedded throttling device applied to a gas static pressure bearing, which comprises a gas guide, a throttling column and an elastic piece, the gas guide is provided with a first opening, the elastic piece is provided with a second opening, and the throttling column passes through the first opening and the second opening in sequence; the gas guide and the throttling column form a throttling gap for gas passing at the first opening, the elastic piece and the throttling column abut at the second opening, a first gas cavity is formed among the gas guide, the throttling column and the elastic piece, the throttling gap and the first gas cavity are in communication, a second gas cavity is formed among the elastic piece, the throttling column and a main shaft rotor corresponding to the gas static pressure bearing; wherein the throttling column forms an air inlet hole at the first gas cavity and an air outlet hole at the contact position with the main shaft rotor, and after external gas passes through the throttling gap and the first gas cavity, the external gas enters the throttling column through the air inlet hole and enters the second gas cavity through the air outlet hole.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of ultra-precision manufacturing equipment, in particular to an embedded throttling device. BACKGROUND

[0002] Precision and ultra-precision machining is an important processing method in the industries of aerospace, national defense, optics and optoelectronic communication, etc., and is an important indicator to measure the overall manufacturing strength of a country. Precision and ultra-precision machining mainly relies on precision and ultra-precision machining equipment, and bearings, as key supporting components of precision and ultra-precision equipment, directly affect the development of precision and ultra-precision machining technology.

[0003] In precision and ultra-precision machining, gas static pressure bearings are increasingly valued by people, mainly because compared with liquid static pressure bearings, gas static pressure bearings have unique "gas film homogenization effect", high precision, no heating, no crawling, low friction, no pollution and high speed, etc., and are suitable for ultra-precision machining with high cleanliness requirements, and are widely used in advanced manufacturing technology fields such as ultra-precision spindles, ultra-precision guideways, semiconductor detection and microelectronic manufacturing.

[0004] However, due to the obvious compressibility and very small viscosity of gas, the load capacity of the gas static pressure bearing is small, the stiffness is small and the stability is poor. When the gas cavity volume effect is greater than the extrusion film effect, the damping effect is weakened, and the gas static pressure bearing will produce large vibration under the action of small disturbance, the system is difficult to quickly reach stability, and the surface of the bearing will be damaged.

[0005] In order to improve the stiffness and load capacity of the gas static pressure bearing, the research of domestic and foreign peers mainly develops from three aspects: parameter improvement type, self-control type and active control type. The disadvantages of the parameter improvement type are: space limitation, at a higher gas supply pressure, the bearing gas film is easy to produce gas hammer and self-excited whirling instability phenomenon. The disadvantages of the self-control type are: once the structure of the throttling device is determined, the throttling characteristics cannot be changed, and the flexible control ability is lacking. The disadvantages of the active control type are: complex structure, large size, can only be placed outside the bearing body, slow response speed when transmitting pressure, affecting the improvement of dynamic stiffness, and it is difficult to put into practical use.

[0006] The existing throttling methods for improving the stiffness and load capacity of the gas static pressure bearing have the above disadvantages, so they have not been fully applied in ultra-precision spindles, ultra-precision guideways and other ultra-precision equipment, and have not been mass-produced as modular components. SUMMARY

[0007] In view of the above problems, the present application is proposed to provide an embedded throttling device which overcomes the above problems or at least partially solves the above problems.

[0008] According to one aspect of the present application, an in-line throttling device for a gas bearing is provided, comprising: a gas guide, a throttling column and an elastic member; the gas guide is provided with a first opening, the elastic member is provided with a second opening, and the throttling column passes through the first opening and the second opening in sequence; the gas guide and the throttling column form a throttling gap for gas passing at the first opening, the elastic member and the throttling column abut at the second opening, a first gas cavity is formed between the gas guide, the throttling column and the elastic member, and the throttling gap is in communication with the first gas cavity, a second gas cavity is formed between the elastic member, the throttling column and a main shaft rotor corresponding to the gas bearing; wherein the throttling column forms an inlet hole at the first gas cavity and an outlet hole at the contact position with the main shaft rotor, and after the external gas passes through the throttling gap and the first gas cavity, it enters the throttling column through the inlet hole and enters the second gas cavity through the outlet hole.

[0009] Optionally, in the throttling device according to the present application, further comprising: a housing, which is a hollow structure through from top to bottom, and the gas guide, the throttling column and the elastic member are all arranged in the hollow structure.

[0010] Optionally, in the throttling device according to the present application, further comprising: an end cover arranged at the opening side of the housing; wherein the end cover, the gas guide and the throttling column form a third gas cavity, and the third gas cavity is in communication with the throttling gap; the end cover is formed with a gas passing hole, and the external gas enters the third gas cavity through the gas passing hole and then enters the throttling gap.

[0011] Optionally, in the throttling device according to the present application, the diameter of the gas passing hole is consistent with that of the inlet hole.

[0012] Optionally, in the throttling device according to the present application, the outlet hole is configured as a throttling ring, the throttling ring is provided with a throttling small hole, and the diameter of the throttling small hole is less than 0.2 mm.

[0013] Optionally, in the throttling device according to the present application, the throttling ring is arranged in the throttling column and is in interference fit with the throttling column.

[0014] Optionally, in the throttling device according to the present application, the gas guide is fixedly connected to the inner side wall of the housing along the side close to the end cover; and the elastic member is arranged at the side of the gas guide away from the end cover and is fixedly connected to the inner side wall of the housing.

[0015] Optionally, in the throttling device according to the present application, the throttling ring and the throttling column are bonded by epoxy resin or metal glue, and the lower end surface of the throttling ring is flush with the lower end surface of the throttling column.

[0016] Optionally, in the throttling device according to the present application, the outer side wall of the housing is in interference fit with the inner hole of the radial bearing of the gas bearing.

[0017] Optionally, in the throttle device according to the present application, the elastic member is spring steel.

[0018] Optionally, in the throttle device according to the present application, the elastic member is configured to deform towards the gas guide when the main shaft rotor is close to the aerostatic bearing, so as to increase the throttle gap, the gas entering the first gas cavity, the gas finally entering the second gas cavity, the pressure in the second gas cavity, and the aerostatic bearing moving away from the main shaft rotor; and when the main shaft rotor is away from the aerostatic bearing, the elastic member deforms towards the main shaft rotor, so as to decrease the throttle gap, the gas entering the first gas cavity, the pressure in the second gas cavity, and the gas finally entering the second gas cavity, and the aerostatic bearing moving towards the main shaft rotor.

[0019] According to the scheme of the present application, the elastic member and the throttle column connected thereto will deform with the change of the gas film pressure, in this way, the pressure in the second gas cavity is changed, the gas pressure flowing through the gas outlet is changed, and the pressure distribution of the gas film is changed, so as to automatically adjust the load capacity and stiffness of the aerostatic bearing, the adjustment accuracy is higher, and the load capacity, stiffness and stability of the aerostatic bearing are maximized.

[0020] According to the scheme of the present application, the throttle device provided has simple and compact structure, is easy to control, can realize high-precision throttle control, meets the demand of the existing aerostatic bearing for rapid suppression of micro-vibration, can significantly improve the load capacity and stiffness of the aerostatic bearing, and is suitable for advanced manufacturing technology fields such as ultra-precision spindle, ultra-precision guide rail, semiconductor detection and micro-electronic manufacturing.

[0021] The above description is only a summary of the technical scheme of the present application, in order to more clearly understand the technical means of the present application, the content of the specification can be implemented, and in order to make the above and other purposes, characteristics and advantages of the present application more obvious and easy to understand, the following specific embodiments of the present application are described. BRIEF DESCRIPTION OF DRAWINGS

[0022] Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments. The accompanying drawings are included to provide a description of the preferred embodiments and are not meant to limit the present application. Furthermore, the same reference numerals are used throughout the several drawings to represent similar components. In the drawings:

[0023] Figure 1 a top view of an aerostatic bearing 100 according to an embodiment of the present application is shown;

[0024] Figure 2 a sectional view of an embedded throttle device 200 according to an embodiment of the present application is shown.

[0025] Figure 3 Fig. 1 shows a schematic diagram of a structure in which an embedded throttling device 200 according to an embodiment of the present application is installed on other aerostatic bearings 100. DETAILED DESCRIPTION

[0026] Exemplary embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. Although exemplary embodiments of the present disclosure are shown in the drawings, it is understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. Rather, these embodiments are provided so that the present disclosure can be more thoroughly understood, and the scope of the present disclosure can be accurately conveyed to those skilled in the art.

[0027] In the description of the present specification, unless otherwise explicitly specified and limited, the terms "connection", "fixation", and the like should be understood in a broad sense. In addition, the terms "front", "back", "up", "down", "inner", "outer", "top", "bottom", and the like indicate the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or units referred to must have a particular direction, be constructed and operated in a particular orientation, and therefore should not be understood as limiting the present application.

[0028] The aerostatic bearing is also called an externally pressurized gas bearing, and its working principle is that an external gas supply system provides high-pressure gas for the aerostatic bearing. The compressed gas enters the bearing gap (also called the load-carrying gap, the gap between the bearing and the main shaft rotor) after passing through the throttler provided in the other aerostatic bearing, thereby realizing the load-carrying effect.

[0029] In order to ensure that the aerostatic bearing obtains better characteristics, it is required that the load-carrying gap be small, and the gap value is usually 5-20 μm. When the load-carrying gap changes, the gas mode pressure distribution and the load-carrying force of the bearing will also change. The throttler design is an important part of the aerostatic bearing design, and directly affects the performance of the bearing.

[0030] However, most of the existing throttlers have the problems of complex structure, large size, and can only be externally placed outside the bearing body, slow response speed when transmitting pressure, affecting the improvement of dynamic stiffness, and difficulty in practical application.

[0031] To solve the above problems, the scheme of the present application is proposed. An embodiment of the present application provides an embedded throttling device. The throttling device is embedded in the radial bearing inner hole of the aerostatic bearing. In combination with Figures 1-3 The throttling device provided in the embodiment will be described. Among them, Figure 1 Fig. 1 shows a top view of the aerostatic bearing 100 according to an embodiment of the present application. Figure 2A cross-sectional view of an embedded throttling device 200 according to an embodiment of the present invention is shown. Figure 3 A schematic diagram of an embedded throttling device 200 installed on another hydrostatic bearing 100 according to an embodiment of the present invention is shown.

[0032] It is worth noting that gas static bearings can be divided into various types such as thrust bearings and radial bearings. The embedded throttling device provided in this embodiment can be applied to various gas static bearings with internal bores, and this embodiment does not impose any limitations on it. In this embodiment, only radial bearings are used as an example for explanation.

[0033] like Figure 1 As shown, the surface of the gas static pressure bearing 100 is uniformly provided with a plurality of bearing inner holes 110, and a throttling device can be installed in each bearing inner hole 110. The bearing inner holes 100 are generally configured as cylindrical and are uniformly arranged in the radial direction of the gas static pressure bearing 100.

[0034] The throttling device 200 is fixedly connected in the bearing inner bore 110. Specifically, the throttling device 200 is interference-fitted with the bearing inner bore 110 and is bonded to the bearing inner bore 110 by epoxy resin adhesive or metal adhesive.

[0035] like Figure 2 As shown, the throttling device 200 includes a housing 210, an end cap 220, an air guide 230, a throttling column 240, and an elastic element 250. The overall shape of the throttling device 200 is the same as that of the bearing inner hole 110, both being cylindrical structures. Its dimensions are optimally selected at φ8mm x 6.6mm, where the diameter is φ8mm and the height is φ6.6mm.

[0036] The housing 210 is a hollow structure that extends vertically. An interference fit is achieved between the outer wall of the housing 210 and the inner bore 110 of the bearing, thus fixing the throttling device 200 within the bearing inner bore 110. It is easy to understand that the shape of the housing 210 must match the inner diameter 110 of the bearing. For example, if the inner diameter 110 of the bearing is cylindrical, then the housing 210 must also be cylindrical.

[0037] End cap 220 is laid on the open side of the upper end of housing 210. End cap 220 is provided with vent hole 221. The air intake channel 101 provided on gas static pressure bearing 100 inputs gas into the throttling device 200 through vent hole 221.

[0038] The air guide 230, the throttling column 240, and the elastic element are all disposed within the hollow structure of the housing 210. The air guide 230 is disposed below the end cap 220, and the elastic element 250 is disposed below the air guide 230. Both the air guide 230 and the elastic element 250 are bonded to the inner wall of the housing 210 by epoxy resin or metal glue.

[0039] The gas guide 230 is provided with a first opening 231, and the elastic member 250 is provided with a second opening 251, and the throttling column 240 passes through the first opening 231 and the second opening 251 in sequence. The throttling column 240 abuts against the elastic member 250 at the second opening 251, and forms a throttling gap 201 for gas passing through with the gas guide 230 at the first opening 231. In other words, the gas guide 230 and the elastic member 250 are both provided in a "funnel shape", and the throttling column 240 passes through the openings of the two funnels respectively. Preferably, the elastic member 250 can be an elastic film or spring steel (spring steel refers to steel specially used for manufacturing springs and elastic elements due to its elasticity in the quenched and tempered state. The elasticity of the steel depends on its ability to elastically deform, i.e. within a specified range, the ability to elastically deform allows it to bear a certain load without permanent deformation after the load is removed).

[0040] In some embodiments, the throttling column 240 and the elastic member 250 are bonded with epoxy-based cement or metal glue.

[0041] With continued reference to Figure 2 The end cover 220, the gas guide 230 and the throttling column 240 form a third gas cavity 202. The gas guide 230, the throttling column 240 and the elastic member 250 form a first gas cavity 203. The throttling column 240, the elastic member 250 and the shell 210 form a second gas cavity 204. The throttling column 240 forms an air inlet hole 241 at the first gas cavity 203, and forms an air outlet hole 242 at the bottom.

[0042] In some embodiments, the throttling ring 243 is in interference fit with the throttling column 240 and is bonded with epoxy-based cement or metal glue.

[0043] It should be noted that the bottom of the throttling ring 243 should be flush with the bottom of the throttling column 240. The size of the air outlet hole 242 is most preferably less than φ0.2mm.

[0044] In some embodiments, the air passing hole 22 on the end cover 210 and the air inlet hole 241 on the throttling column 240 have the same diameter. Preferably, φ0.1mm.

[0045] After the external gas enters the inside of the throttling device through the air passing hole 221, it first enters the third gas cavity 202, then passes through the throttling gap 201 into the first gas cavity 203, and then passes through the air inlet hole 241 on the throttling column 240 into the inside of the throttling column 240, and finally flows out from the air outlet hole 242 at the bottom of the throttling column 240, the flowing gas enters the air mode formed between the gas static pressure bearing 100 and the main shaft rotor 300, and further fills the second gas cavity 204.

[0046] The gas film between the aerostatic bearing 100 and the spindle rotor 300 separates the aerostatic bearing 100 and the spindle rotor 300 to reduce the friction therebetween. The elastic member 250 and the throttling column 240 connected thereto deforms with the change of the gas film pressure, in this way, changes the pressure in the second gas cavity 204, and simultaneously changes the gas pressure flowing through the gas outlet hole 242, and further changes the pressure distribution of the gas film, so as to realize the automatic adjustment of the load capacity and stiffness of the aerostatic bearing 100, the adjustment precision is higher, and the load capacity, stiffness and stability of the aerostatic bearing are maximized.

[0047] Specifically, when the spindle rotor 300 approaches the aerostatic bearing 100, the elastic member 250 deforms towards the gas guide 230, so as to increase the throttling gap 201, increase the gas entering the first gas cavity 203, and finally increase the gas entering the second gas cavity 204, increase the pressure in the second gas cavity 204, and move the aerostatic bearing 100 away from the spindle rotor 300.

[0048] When the spindle rotor 300 is away from the aerostatic bearing 100, the elastic member 250 deforms towards the spindle rotor 300, so as to decrease the throttling gap 201, decrease the gas entering the first gas cavity 203, and finally decrease the gas entering the second gas cavity 204, decrease the pressure in the second gas cavity 204, and move the aerostatic bearing 100 towards the spindle rotor 300.

[0049] In a specific example, the use process of the throttling device 200 in the above embodiment is described as follows:

[0050] When the throttling device 200 works, the compressed gas with a pressure of 0.6 MPa is connected to the gas passing hole 221 of the throttling device through the gas inlet channel 101, the gas enters the gap between the bearing and the spindle rotor 300 through the throttling gap 201, the gas inlet hole 241 on the throttling column 241 and the throttling small hole 242 on the throttling ring 243, and forms a gas film, and the pressure at this time is P0.

[0051] When the spindle rotor 300 is subjected to a downward load W (i.e., the spindle rotor 300 is away from the aerostatic bearing 100), the aerostatic bearing 100 and the spindle rotor shaft diameter 300 generate an eccentricity e, the gap between the aerostatic bearing 100 and the spindle rotor 300 is reduced to h = h0 - e, the gap impedance of the gas flow is increased, the pressure in the second gas cavity 204 is increased to P = P0 + ΔP, the elastic diaphragm 250 is deformed upward (i.e., deformed toward the gas guide 230), the throttle gap 201 between the throttle column 240 and the gas guide 230 is increased, the fluid gap impedance is reduced, the gas entering the first gas cavity 203 is increased, the gas flow into the second gas cavity 204 is increased, the pressure P in the second gas cavity 204 is further increased, causing the aerostatic bearing 100 and the spindle rotor shaft diameter 300 to move away from each other (i.e., the gap between the aerostatic bearing 100 and the spindle rotor shaft diameter 300 is increased).

[0052] When the spindle rotor 300 is subjected to an upward load W (i.e., the spindle rotor 300 is close to the aerostatic bearing 100), the aerostatic bearing 100 and the spindle rotor shaft diameter 300 generate an eccentricity e, the gap between the aerostatic bearing 100 and the spindle rotor 300 is increased to h' = h0 + e, the gap impedance of the gas flow is increased, the pressure in the second gas cavity 204 is reduced to P' = P0 - ΔP, the elastic diaphragm 250 is deformed downward (i.e., deformed toward the spindle rotor 300), the throttle gap 201 between the throttle column 240 and the gas guide 230 is reduced, the fluid gap impedance is increased, the gas entering the first gas cavity 203 is reduced, the gas flow into the second gas cavity 204 is reduced, the pressure P in the second gas cavity 204 is further reduced, causing the aerostatic bearing 100 and the spindle rotor shaft diameter 300 to move close to each other (i.e., the gap between the aerostatic bearing 100 and the spindle rotor shaft diameter 300 is reduced).

[0053] According to the throttle device 200 provided by the embodiment, the structure is simple and compact, easy to control, and can realize high-precision throttle control, meet the demand of the existing aerostatic bearing 100 for rapid suppression of micro-vibration, significantly improve the load capacity and stiffness of the aerostatic bearing, and be suitable for advanced manufacturing technical fields such as ultra-precision spindles, ultra-precision guideways, semiconductor detection, and microelectronic manufacturing.

[0054] A10. The apparatus of A2, wherein the outer sidewall of the housing is interference fit with an inner bore of a radial bearing of the aerostatic bearing. A11. The apparatus of A1, wherein the elastic member is spring steel.

[0055] In the description provided herein, a large number of specific details are explained. However, it can be understood that embodiments of the application can be practiced without these specific details. In some instances, well-known methods, structures and techniques have not been shown in detail in order not to obscure the understanding of this description.

[0056] Similarly, it is to be understood that the features of the present application that are of a proprietary nature are set forth in the appended claims. Those skilled in the art will realize that the preferred embodiments of the present application are capable of out-of-the-mill applications, and, thus, functions and / or elements of the preferred embodiments can be present in applications other than this application. The following detailed description, given by way of example, but not intended to limit the application solely to the embodiments described, includes various examples of the application. It will be appreciated that those examples are given for purposes of disclosure and that the application is not limited to those examples.

[0057] Those skilled in the art will understand that the modules, or units, or components of the devices in the examples disclosed herein can be arranged in a device as described in the examples, or alternatively can be located in one or more devices different from the devices in the examples. The modules in the foregoing examples can be combined into one module or further divided into multiple sub-modules.

[0058] Those skilled in the art will understand that the modules in the devices in the examples can be adaptively changed and disposed in one or more devices different from the examples. The modules or units or components in the examples can be combined into one module or unit or component, and further can be divided into multiple sub-modules or sub-units or sub-components. All the features disclosed in this specification (including the claims, abstract, and drawings) and all the processes or units of any method or device so disclosed can be combined in any combination, except where such features or processes or units are mutually exclusive. Each feature disclosed in this specification (including the claims, abstract, and drawings) can be replaced by alternative features providing the same, equivalent, or similar functionality unless expressly stated otherwise.

[0059] Further, those skilled in the art will understand that the combination of features of different embodiments means within the scope of the application and forms different embodiments, although some of the embodiments described herein include certain features rather than others included in other embodiments.

[0060] As used herein, unless otherwise specified, the use of the ordinal adjectives "first", "second", "third", etc., merely to distinguish between two or more of the same object, and does not imply a time, spatial, ranking, or any other kind of ordering of the objects.

[0061] While the application has been described in accordance with the various embodiments shown and described, it is to be understood that the application is not limited to those precise embodiments, and that various modifications and changes can be made by those skilled in the art without departing from the scope of the present application. It is intended that the scope of the application should only be limited as recited in the appended claims.

Claims

1. An embedded throttling device for a gas static pressure bearing, comprising: Air guides, throttling columns, elastic elements, housings, and end caps; The air guide is provided with a first opening, the elastic element is provided with a second opening, and the throttling column passes through the first opening and the second opening in sequence. The gas guide and the throttling column form a throttling gap at the first opening for gas to pass through. The elastic element and the throttling column are bonded to the second opening by epoxy resin or metal glue. A first air chamber is formed between the gas guide, the throttling column and the elastic element, and the throttling gap is connected to the first air chamber. A second air chamber is formed between the elastic element, the throttling column and the main shaft rotor corresponding to the gas static pressure bearing. The throttling column has an air inlet at the first air chamber and an air outlet at the contact position with the main shaft rotor. After passing through the throttling gap and the first air chamber, the external gas enters the throttling column through the air inlet and enters the second air chamber through the air outlet. The shell is a hollow structure that runs vertically through the interior and exterior, and the air guide, throttling column and elastic element are all disposed within the hollow structure. An end cap is disposed on the opening side of the housing. The air guide is fixed to the inner wall of the housing along the side close to the end cap. The elastic element is disposed on the side of the air guide away from the end cap and fixed to the inner wall of the housing. The end cap, the air guide, and the throttling column form a third air chamber. The third air chamber is in communication with the throttling gap. An air passage is formed on the end cap. External gas enters the third air chamber through the air passage and then enters the throttling gap.

2. The apparatus of claim 1, wherein, The diameter of the vent is the same as that of the inlet.

3. The apparatus of claim 1, wherein, The air outlet is configured as a throttling ring, and the throttling ring is provided with a throttling orifice, the diameter of which is less than 0.2 mm.

4. The apparatus of claim 3, wherein, The throttling ring is disposed inside the throttling column and is interference-fitted with the throttling column.

5. The apparatus of claim 4, wherein, The throttling ring and the throttling column are bonded together with epoxy resin or metal adhesive, and the lower end face of the throttling ring is flush with the lower end face of the throttling column.

6. The apparatus of claim 1, wherein, The elastic element is configured such that when the main shaft rotor approaches the gas static bearing, the elastic element deforms towards the gas guide, thereby increasing the throttling gap, increasing the amount of gas entering the first gas chamber, and ultimately increasing the amount of gas entering the second gas chamber, increasing the pressure in the second gas chamber, and causing the gas static bearing to move away from the main shaft rotor. as well as When the main shaft rotor moves away from the gas hydrostatic bearing, the elastic element deforms towards the main shaft rotor, thereby reducing the throttling gap, reducing the amount of gas entering the first gas chamber, and ultimately reducing the amount of gas entering the second gas chamber. As a result, the pressure in the second gas chamber decreases, and the gas hydrostatic bearing moves towards the main shaft rotor.

7. The apparatus of claim 1, wherein, The outer wall of the housing is interference-fitted with the radial bearing inner hole of the gas hydrostatic bearing.

8. The apparatus of claim 1, wherein, The elastic element is made of spring steel.

Images