A vacuum adsorption type porous gas static pressure thrust bearing

Abstract

The present invention discloses a vacuum adsorption type porous gas static pressure thrust bearing, including a bearing base, a gas static pressure bearing throttle and a thrust plate. The bearing base is made of aluminum alloy material. A circular negative pressure cavity is provided at the center of the lower end surface of the bearing base, and a central blind hole coaxial with the circular negative pressure cavity is provided at the top. An annular groove is provided on the lower end surface of the bearing base and around the circular negative pressure cavity. The cross section of the annular groove is rectangular, and two annular pressure equalizing grooves are provided on the top surface of the annular groove. A porous material ring serving as a gas static pressure bearing throttle is installed in the annular groove. The porous material ring is made of isotropic porous material, and its end face protrudes from the lower end surface of the bearing base. An air supply hole and an air outlet hole are provided on the side of the bearing base. The air supply hole is connected to the two annular pressure equalizing grooves, and the air outlet hole is connected to the central blind hole. The present invention can improve the pressure relief effect by increasing the S a The / S value effectively improves the bearing stiffness to solve the problem of insufficient stiffness of the gas static pressure bearing under low load.

Description

Technical Field

[0001] The invention relates to a gas static pressure thrust bearing, in particular to a porous gas static pressure thrust bearing with high rigidity and high stability under low load. Background Art

[0002] Gas static pressure bearings are widely used in precision machining and measurement equipment due to their high motion accuracy, small friction loss, heat generation and deformation. The different bearing throttles directly affect their load-bearing capacity and stiffness. The throttling methods used by gas static pressure bearings are mainly small hole throttling, slit throttling, surface throttling and porous throttling. Due to the large air supply area of ​​the porous throttle and the uniform distribution of the pressure field, the porous gas static pressure bearing has the advantages of large load-bearing capacity and stiffness, good stability and simple structure compared with other traditional gas static pressure bearings. When the porous gas static pressure bearing is working, the stiffness of the bearing will also change with the change of the air film thickness. When the bearing load is low, the air film thickness is large, and the bearing stiffness is also low at this time. Therefore, under low bearing load, the stiffness of ordinary porous gas static pressure bearings still cannot meet the design and use requirements. Summary of the invention

[0003] In order to overcome the problems of the prior art, an object of the present invention is to provide a vacuum adsorption porous gas static pressure thrust bearing to solve the problem of insufficient stiffness of the gas static pressure bearing under low load.

[0004] The technical solution adopted by the present invention to solve the above technical problems is: a vacuum adsorption type porous gas static pressure thrust bearing, including a bearing base, a gas static pressure bearing throttle and a thrust plate, the bearing base is made of aluminum alloy material, a circular negative pressure cavity is provided at the center of the lower end surface of the bearing base, a central blind hole coaxial with the circular negative pressure cavity is provided on the top of the circular negative pressure cavity, an annular groove is provided on the lower end surface of the bearing base and around the circular negative pressure cavity, the cross-section of the annular groove is rectangular, and the groove top surface of the annular groove is Two annular pressure-equalizing grooves are provided; a porous material ring serving as a gas static pressure bearing throttle is installed in the annular groove, and the porous material ring is made of isotropic porous material, and the material can be porous graphite, porous bronze, porous stainless steel, etc., and the end face of the porous material ring protrudes from the lower end face of the bearing base; an air supply hole and an air outlet hole are provided on the side of the bearing base, the air supply hole is communicated with the two annular pressure-equalizing grooves, and the air outlet hole is communicated with the central blind hole, and the air supply hole and the air outlet hole intersect at 90 degrees in space.

[0005] Furthermore, in the present invention, the porous material ring cooperates with the annular groove on the lower end surface of the bearing base and is bonded with epoxy adhesive.

[0006] The end surface of the porous material ring is the bearing working surface, and the thrust plate is arranged opposite to the bearing working surface.

[0007] The circular cross-sectional area of ​​the circular negative pressure cavity is S a The sum of the circular cross-sectional area of ​​the circular negative pressure cavity and the annular cross-sectional area of ​​the annular groove is S, 0.2<S a / S<0.35.

[0008] Compared with the prior art, the present invention has the following beneficial effects:

[0009] (1) Under low load conditions, the stiffness of the bearing can be effectively improved, and the bearing capacity and stiffness can be adjusted by changing the area of ​​the negative pressure cavity.

[0010] (2) The use of isotropic porous materials as the throttle of the gas hydrostatic bearing ensures uniform porosity, consistent permeability and isotropy. Compared with the adsorption-type small-void throttling gas hydrostatic support bearing, the "air hammer" phenomenon is less likely to occur due to the absence of air cavities, thereby improving the stability of the gas hydrostatic bearing. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 It is a main sectional view of the vacuum adsorption type porous gas static pressure thrust bearing of the present invention;

[0012] Figure 2 It is a cross-sectional view of a bearing base of a vacuum adsorption type porous gas static pressure thrust bearing of the present invention;

[0013] Figure 3 This is a working principle diagram of the vacuum adsorption type porous gas static pressure thrust bearing of the present invention;

[0014] Figure 4 The figure is a comparison of the stiffness of the vacuum adsorption type porous gas static pressure thrust bearing of the present invention under different loads. DETAILED DESCRIPTION

[0015] The technical solution of the present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. The described specific embodiments are only used to explain the present invention and are not intended to limit the present invention.

[0016] like Figure 1 As shown, a vacuum adsorption type porous gas static pressure thrust bearing proposed by the present invention includes a bearing base 2, a gas static pressure bearing throttle and a thrust plate 1.

[0017] like Figure 2As shown, the bearing base 2 is made of aluminum alloy material, a circular negative pressure cavity 5 is provided at the center of the lower end surface of the bearing base 2, a center blind hole coaxial with the circular negative pressure cavity 5 is provided on the top of the circular negative pressure cavity 5, an annular groove is provided on the lower end surface of the bearing base 2 and around the circular negative pressure cavity 5, the cross-section of the annular groove 6 is rectangular, and two annular pressure equalizing grooves 7 are provided on the top surface of the annular groove 6.

[0018] like Figure 1 As shown, a porous material ring 3 as a gas static pressure bearing throttle is installed in the annular groove 6. The porous material ring 3 is made of isotropic porous material. The porous material ring 3 cooperates with the annular groove 6 on the lower end face of the bearing base 2 and is bonded with epoxy adhesive. The end face of the porous material ring 3 protrudes from the lower end face of the bearing base 2; the end face of the porous material ring 3 is the bearing working surface 4 (the bearing working surface 4 is ultra-precision turned to meet the design and use requirements), and the thrust plate 1 is arranged opposite to the bearing working surface 4. The side of the bearing base 2 is provided with an air supply hole 8 and an air outlet hole 9. The air supply hole 8 is connected to two annular pressure equalizing grooves 9, and the air outlet hole 8 is connected to the central blind hole. The air supply hole 8 and the air outlet hole 9 intersect at 90 degrees in space.

[0019] In the present invention, the circular cross-sectional area of ​​the circular negative pressure cavity 5 provided on the lower end surface of the bearing base 2 is S a The sum of the circular cross-sectional area of ​​the circular negative pressure cavity 5 and the annular cross-sectional area of ​​the annular groove 6 provided on the lower end surface of the bearing base 2 is S. In the present invention, it is recommended that 0.2 < S a / S<0.35.

[0020] like Figure 3 As shown, the gas source is connected to the air supply hole 8, and the vacuum generator is connected to the air outlet 9. The high-pressure gas Ps enters the bearing gap h (the gap between the bearing working surface 4 and the thrust plate 1) through the airway (the air inlet 8—two annular pressure-equalizing grooves 7) and an isotropic porous material ring, such as a porous bronze ring 3, to form a thin air film in the bearing gap h. The gas entering the air film gap is discharged in two directions: a part Pa flows outward along the gap between the upper and lower supports into the atmosphere, and the pressure drops to atmospheric pressure; the other part Pv flows inward through the circular negative pressure cavity 5 to the air outlet 9 and is sucked away by the vacuum generator. Thus, positive pressure areas and negative pressure areas are formed in the working gap of the bearing. The positive pressure area generates buoyancy to float the thrust surface of the bearing, giving it a certain load-bearing capacity, while the negative pressure area applies a certain load to the thrust surface of the bearing, reducing the bearing's load-bearing capacity. When the two reach a state of equilibrium, the air film gap is maintained within a stable range, so that the bearing has a suitable stiffness and can improve the stability of the bearing. The bearing is lightly loaded and 0.2 a / S<0.35, by increasing S a ​ / S value can effectively improve the bearing stiffness, such as Figure 4 The stiffness ratio of the bearing under different loads is shown.

[0021] Although the present invention has been described above in conjunction with the accompanying drawings, the present invention is not limited to the above-mentioned specific embodiments, which are merely illustrative rather than restrictive. Under the guidance of the present invention, ordinary technicians in this field can make many modifications without departing from the purpose of the present invention, all of which are within the protection of the present invention.

Claims

1. A vacuum adsorption type porous gas static pressure thrust bearing, comprising a bearing base (2), a gas static pressure bearing throttle and a thrust plate (1), characterized in that: The bearing base (2) is made of aluminum alloy material. A circular negative pressure cavity (5) is provided at the center of the lower end surface of the bearing base (2). A central blind hole coaxial with the circular negative pressure cavity (5) is provided at the top of the circular negative pressure cavity (5). An annular groove (6) is provided on the lower end surface of the bearing base (2) surrounding the circular negative pressure cavity (5). The circular cross-sectional area of ​​the circular negative pressure cavity (5) is S a The sum of the circular cross-sectional area of ​​the circular negative pressure chamber (5) and the annular cross-sectional area of ​​the annular groove (6) is S, 0.2<S a / S<0.35; the cross section of the annular groove (6) is rectangular, and the top surface of the annular groove (6) is provided with two annular pressure equalizing grooves (7); A porous material ring (3) serving as a gas static pressure bearing throttle is installed in the annular groove (6); the porous material ring (3) is made of an isotropic porous material, and the material is selected from any one of porous graphite, porous bronze, and porous stainless steel; the end surface of the porous material ring (3) protrudes from the lower end surface of the bearing base (2); An air supply hole (8) and an air outlet hole (9) are provided on the side of the bearing base (2); the air supply hole (8) is communicated with the two annular pressure equalizing grooves (7); the air outlet hole (9) is communicated with the central blind hole; the air supply hole (8) and the air outlet hole (9) intersect at 90 degrees in space.

2. The vacuum adsorption type porous gas static pressure thrust bearing according to claim 1, characterized in that: The porous material ring (3) cooperates with the annular groove (6) on the lower end surface of the bearing base (2) and is bonded with epoxy glue.

3. The vacuum adsorption type porous gas static pressure thrust bearing according to claim 1, characterized in that: The end surface of the porous material ring (3) is a bearing working surface (4), and the thrust plate (1) is arranged opposite to the bearing working surface (4).

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