Small-hole throttler with cavity for single-hole throttling air static pressure supporting bearing

Abstract

The utility model discloses a small hole throttler with a cavity for a single-hole throttling air static pressure support bearing, which comprises a throttling small hole, a conical air cavity and a cylindrical air cavity, one end opening of the throttling small hole is communicated with an air supply channel, the other end of the throttling small hole is communicated with the thin end of the conical air cavity, and the cylindrical air cavity is communicated with the conical air cavity. And the thick end of the conical air cavity is communicated with the cylindrical air cavity. The conical air cavity is arranged at the outlet position of the small hole, flow turning caused by sudden change of a flow channel can be weakened, generation of a supersonic speed area at an inlet can be weakened, the risk of micro-vibration generated by vortex flow is further reduced, the cavity volume is smaller than 5% of the total operation air capacity, and vibration of the air hammer can be effectively weakened; and the cylindrical air cavity is arranged above the conical air cavity, so that the bearing capacity of the bearing can be effectively increased.

Description

Technical Field

[0001] The utility model relates to a small-hole throttle with a cavity for a single-hole throttling air static pressure support bearing, and belongs to the field of ultra-precision processing and measurement. Background Art

[0002] Aerostatically supported bearings are crucial components in ultra-precision machining and measurement equipment. These bearings utilize an external air supply and offer zero friction, excellent vibration isolation, and high precision. Small-orifice restrictors are the most widely used due to their ease of manufacture and maintenance.

[0003] The throttle used in aerostatic bearings has a direct impact on the mechanical properties of the bearings. Generally, the throttle directly affects the static load-bearing capacity and self-excited vibration characteristics of the bearings. For cavityless bearings, the self-excited vibration performance is better, but the bearing load-bearing capacity is low. For the use of air cavities, the load-bearing capacity is greatly improved, but it is easy to cause problems such as micro-vibration and air hammer vibration, which weakens the operating stability of the bearing. At present, the static performance of aerostatic bearings has been studied in depth, and the research results are widely used in bearing design. However, how to improve the self-excited vibration performance while improving static performance such as static load through throttling parameter design is currently less involved in engineering design. By reasonably designing the throttle parameters and cavity shape, it is possible to ensure that the bearing has controllable self-excited vibration while improving the static performance of the aerostatic bearing, which is of great significance to improving the comprehensive mechanical performance of the bearing.

[0004] The self-excited vibration of aerostatic bearings includes micro-vibration and air hammer vibration. Studies have shown that when the air cavity volume is small, the air hammer vibration and micro-vibration of the bearing are weak, but the bearing capacity is also weakened. Therefore, compared with the cylindrical air cavity, although the use of a simple conical air cavity can help improve the self-excited vibration characteristics of the bearing, the volume of the conical cavity is smaller than that of the cylindrical air cavity, and the bearing capacity is also weaker than the latter. In the design of throttling parameters, if the air cavity shape and volume can be reasonably selected, the ability of the bearing to operate stably can be improved while ensuring the bearing capacity. Summary of the Invention

[0005] The utility model provides a small hole throttle with a cavity for a single-hole throttling air static pressure support bearing. By designing a conical air cavity and a cylindrical air cavity that are arranged in sequence between the small hole and the air film, this configuration has the characteristics of a small hole throttling conical air cavity and a small hole throttling cylindrical air cavity, and can provide sufficient bearing capacity under the premise of weakening self-excited vibration.

[0006] The technical solution of the utility model is:

[0007] A cavity-type small hole throttle for a single-hole throttling air static pressure support bearing comprises a throttling hole, a conical air cavity, and a cylindrical air cavity. One end of the throttling hole is communicated with an air supply channel, the other end of the throttling hole is communicated with the thin end of the conical air cavity, and the thick end of the conical air cavity is communicated with one end of the cylindrical air cavity.

[0008] Furthermore, the cone angle of the conical air cavity at the outlet ranges from 60° to 80°.

[0009] Furthermore, the ratio of the air volume of the conical air cavity to the air volume of the cylindrical air cavity is 1.5-2.

[0010] Furthermore, the cavity volume is less than 5% of the total operating air volume composed of the air cavity and the air film; wherein the cavity volume is the total volume of the cylindrical air cavity and the conical air cavity, and the air cavity is a cylindrical air cavity + a conical air cavity.

[0011] The beneficial effects of the present invention are as follows: the present invention arranges a conical air cavity at the outlet of the throttling orifice, which can weaken the flow turning caused by the sudden change of the flow channel, weaken the generation of the supersonic region at the inlet, and further reduce the risk of micro-vibration caused by the vortex flow. The cavity volume is less than 5% of the total operating air volume, which can effectively weaken the vibration of the air hammer; a cylindrical air cavity is arranged above the conical air cavity, which can effectively increase the bearing capacity. At the same time, compared with the cavityless orifice throttle, the addition of the air cavity improves the bearing capacity, that is, enhances the static performance; compared with the traditional cylindrical cavity orifice throttle, the air volume is reduced, and due to the large cone angle (60°-80°), it is more difficult for the vortex flow to form in the cavity, thereby weakening the influence of the self-excited vibration of the bearing, that is, improving the dynamic performance. This type of orifice throttle helps to improve the self-excited vibration stability while improving the static performance of the bearing, and takes into account the improvement of both the static and dynamic performance of the bearing. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 This is a schematic diagram of a single-hole aerostatic bearing using the small-hole throttle cavity of the utility model;

[0013] Figure 2 This is a comparison of the flow field in the air cavity of a single-hole aerostatic bearing using the small-hole throttle cavity of the utility model and other cavity shapes. Figure 1 ;in, Figure 2 (a) is the "no cavity" working condition, Figure 2 (b) The "cylindrical cavity + cone cavity" working condition proposed by this utility model, Figure 2 (c) is the working condition of "cylindrical cavity + cone cavity (cone angle is too small)", Figure 2 (d) is the “cylindrical cavity” working condition;

[0014] Figure 3This is a comparison of the flow field in the air cavity of a single-hole aerostatic bearing using the small-hole throttle cavity of the utility model and other cavity shapes. Figure 2 ;in, Figure 3 (a) is the "no cavity" working condition, Figure 3 (b) The "cylindrical cavity + cone cavity" working condition proposed by this utility model, Figure 3 (c) is the working condition of "cylindrical cavity + cone cavity (cone angle is too small)", Figure 3 (d) is the “cylindrical cavity” working condition;

[0015] Figure 4 This is a comparison of the flow field in the air cavity of a single-hole aerostatic bearing using the small-hole throttle cavity of the utility model and other cavity shapes. Figure 3 ;in, Figure 4 (a) is the "no cavity" working condition, Figure 4 (b) The "cylindrical cavity + cone cavity" working condition proposed by this utility model, Figure 4 (c) is the working condition of "cylindrical cavity + cone cavity (cone angle is too small)", Figure 4 (d) is the “cylindrical cavity” working condition;

[0016] The numbers in the figure are: supported part-1, air film-2, cylindrical air cavity-3, conical air cavity-4, throttling hole-5, air supply channel-6, bearing body-7. DETAILED DESCRIPTION

[0017] The utility model will be further described below with reference to the accompanying drawings and embodiments, but the content of the utility model is not limited to the scope of the drawings.

[0018] Example 1: Figure 1-Figure 4 As shown, a cavity-type small hole throttle for a single-hole throttling air static pressure support bearing includes a throttling hole 5, a conical air cavity 4, and a cylindrical air cavity 3. One end of the throttling hole 5 is connected to the air supply channel 6, the other end of the throttling hole 5 is connected to the thin end of the conical air cavity 4, and the thick end of the conical air cavity 4 is connected to one end of the cylindrical air cavity 3. The throttling hole 5, the conical air cavity 4, and the cylindrical air cavity 3 are fixed to one side of the bearing body 7.

[0019] In specific applications, the gas is supplied by an external gas source, and the airflow enters the throttling hole 5 through the upstream air supply channel 6. The throttling hole 5 plays a throttling role, and the airflow enters the air cavity from the throttling hole 5: first enters the conical air cavity 4, and then the airflow continues from the conical air cavity 4 to the cylindrical air cavity 3, with a relatively uniform pressure in the entire air cavity; the supported part 1 is subjected to pressure and floats up to form an air film 2. The airflow passes through the cylindrical air cavity 3 and enters the air film 2, and flows out to the outer boundary through the air film 2.

[0020] Furthermore, the cone angle α of the conical air cavity 4 at the outlet ranges from 60° to 80°.

[0021] Furthermore, the air volume ratio of the conical air cavity 4 to the cylindrical air cavity 3 is 1.5-2.

[0022] Furthermore, the length of the throttling hole 5 is 0.5 mm.

[0023] Furthermore, the cavity volume is less than 5% of the total operating air volume formed by the air cavity and the air membrane 2; wherein, the cavity volume is the total volume of the cylindrical air cavity 3 + the conical air cavity 4, the air cavity is the cylindrical air cavity 3 + the conical air cavity 4, and the total operating air volume formed by the air cavity and the air membrane 2 is the total volume of the air membrane 2 + the cylindrical air cavity 3 + the conical air cavity 4.

[0024] Furthermore, the throttling hole diameter is optimally selected within the range of 0.1mm-0.15mm according to the specific operating conditions and the bearing capacity; the diameter of the bearing used, i.e. Figure 1 The diameter of the middle bearing body 7 is 15mm-25mm, which is determined according to the use requirements within the range; the bearing air supply pressure is based on the commonly used range of 0.3MPa-0.7MPa in engineering, which is determined according to the use requirements.

[0025] In order to further illustrate the effectiveness of the cavity-hole throttle of the present invention, the present invention is compared with throttles with different cavity designs. The comparison cloud diagram is as follows: Figure 2-Figure 4 As shown in the comparative experiment, the cylindrical cavity is a cylindrical air cavity, and the conical cavity is a conical air cavity:

[0026] In the three groups of comparative experiments, the length of the throttling hole 5 is 0.5 mm; the diameter of the throttling hole is 0.1 mm; the diameter of the bearing used is 20 mm; and the air supply pressure is 0.5 MPa.

[0027] like Figure 2 As shown in the figure, the first group of comparative experiments are as follows: "(a) No cavity" working condition, "(b) Cylindrical cavity + conical cavity" working condition, "(c) Cylindrical cavity + conical cavity (cone angle is too small)" working condition and "(d) Cylindrical cavity" working condition. In the above working conditions, the design parameters of the cylindrical cavity in the working conditions of "(b) Cylindrical cavity + conical cavity" and "(c) Cylindrical cavity + conical cavity (cone angle is too small)" are the same, with a cavity radius of 0.5mm and a cavity depth of 0.19mm; the volume design parameters of the cavity in the working conditions of "(b) Cylindrical cavity + conical cavity" and "(d) Cylindrical cavity" are the same, with a parameter of 0.375mm. 3; The design parameters of the cone cavity in the "(b) cylindrical cavity + cone cavity" working condition and the "(c) cylindrical cavity + cone cavity (cone angle is too small) working condition" are as follows: the cone angle of the "(b) cylindrical cavity + cone cavity" working condition is 60°, and the cone angle of the "(c) cylindrical cavity + cone cavity (cone angle is too small) working condition" is 15°; under the "(b) cylindrical cavity + cone cavity" working condition, the air volume ratio of the cone cavity 4 to the cylindrical cavity 3 is 1.5, and the air volume ratio of the cone cavity to the cylindrical cavity under the "(c) cylindrical cavity + cone cavity (cone angle is too small) working condition" is 0.24; the comparison results show that: when the "(b) cylindrical cavity + cone cavity" working condition has the same air cavity volume as the "(d) cylindrical cavity" working condition, the "b) cylindrical cavity + cone cavity" working condition weakens the vortex flow in the air cavity, that is, reduces the micro-vibration; the "(b) cylindrical cavity + cone cavity" working condition When the cylindrical cavity size is the same as that of the "(c) cylindrical cavity + conical cavity (cone angle is too small)" working condition, compared with the "(c) cylindrical cavity + conical cavity (cone angle is too small)" working condition, the "b) cylindrical cavity + conical cavity working condition weakens the vortex flow in the air cavity, that is, reduces the micro-vibration; compared with the vortex flow existing in the cavity under the "(c) cylindrical cavity + conical cavity (cone angle is too small)" working condition and the "(d) cylindrical cavity" working condition, in the "(b) cylindrical cavity + conical cavity" working condition, only separation bubbles exist in the air cavity, and no vortex flow is formed, which can make the supported part 1 operate more stably; compared with the "(a) no cavity" working condition, the "(b) cylindrical cavity + conical cavity" working condition improves the bearing capacity, among which the "(b) cylindrical cavity + conical cavity" working condition can provide a bearing capacity of 97.49N, and the "(a) no cavity" working condition can provide a bearing capacity of 50.70N.

[0028] like Figure 3 As shown in the second group of comparative experiments: "(a) No cavity" working condition, "(b) Cylindrical cavity + conical cavity" working condition, "(c) Cylindrical cavity + conical cavity (cone angle is too small)" working condition and "(d) Cylindrical cavity" working condition. In the above working conditions, the design parameters of the cylindrical cavity in the "(b) Cylindrical cavity + conical cavity" working condition and the "(c) Cylindrical cavity + conical cavity (cone angle is too small)" working condition are the same, with a cavity radius of 0.5mm and a cavity depth of 0.145mm; the volume design parameters of the cavity in the "(b) Cylindrical cavity + conical cavity" working condition and the "(d) Cylindrical cavity" working condition are the same, with a parameter of 0.340mm 3; The design parameters of the cone cavity in the "(b) cylindrical cavity + cone cavity" working condition and the "(c) cylindrical cavity + cone cavity (cone angle is too small) working condition" are as follows: the cone angle of the "(b) cylindrical cavity + cone cavity" working condition is 60°, and the cone angle of the "(c) cylindrical cavity + cone cavity (cone angle is too small) working condition" is 15°; under the "(b) cylindrical cavity + cone cavity" working condition, the air volume ratio of the cone cavity 4 to the cylindrical cavity 3 is 2, and the air volume ratio of the cone cavity to the cylindrical cavity in the "(c) cylindrical cavity + cone cavity (cone angle is too small) working condition" is 0.31; the comparison results show that: when the "(b) cylindrical cavity + cone cavity" working condition has the same air cavity volume as the "(d) cylindrical cavity" working condition, the "b) cylindrical cavity + cone cavity" working condition weakens the vortex flow in the air cavity, that is, reduces the micro-vibration; under the "(b) cylindrical cavity + cone cavity" working condition, Compared with the "(c) cylindrical cavity + conical cavity (cone angle is too small)" working condition with the same cylindrical cavity size, the "b) cylindrical cavity + conical cavity working condition weakens the vortex flow in the air cavity, that is, reduces the micro-vibration; compared with the vortex flow in the cavity of the "(c) cylindrical cavity + conical cavity (cone angle is too small)" working condition and the "(d) cylindrical cavity" working condition, in the "(b) cylindrical cavity + conical cavity" working condition, only separation bubbles exist in the air cavity, and no vortex flow is formed, which can make the supported part 1 operate more stably; compared with the "(a) no cavity" working condition, the "(b) cylindrical cavity + conical cavity" working condition improves the bearing capacity, among which the "(b) cylindrical cavity + conical cavity" working condition can provide a bearing capacity of 98.64N, and the "(a) no cavity" working condition can provide a bearing capacity of 50.70N.

[0029] like Figure 4 As shown, the fourth group of comparative experiments: "(a) No cavity" working condition, "(b) Cylindrical cavity + conical cavity" working condition, "(c) Cylindrical cavity + conical cavity (cone angle is too small)" working condition and "(d) Cylindrical cavity" working condition. In the above working conditions, the design parameters of the cylindrical cavity in the "(b) Cylindrical cavity + conical cavity" working condition and the "(c) Cylindrical cavity + conical cavity (cone angle is too small)" working condition are the same, with a cavity radius of 0.5mm and a cavity depth of 0.45mm; the volume design parameters of the cavity in the "(b) Cylindrical cavity + conical cavity" working condition and the "(d) Cylindrical cavity" working condition are the same, with a parameter of 1.091mm 3; The design parameters of the cone cavity in the "(b) cylindrical cavity + cone cavity" working condition and the "(c) cylindrical cavity + cone cavity (cone angle is too small) working condition" are as follows: the cone angle of the "(b) cylindrical cavity + cone cavity" working condition is 80°, and the cone angle of the "(c) cylindrical cavity + cone cavity (cone angle is too small) working condition" is 15°; under the "(b) cylindrical cavity + cone cavity" working condition, the air volume ratio of the cone cavity 4 to the cylindrical cavity 3 is 2, and the air volume ratio of the cone cavity to the cylindrical cavity in the "(c) cylindrical cavity + cone cavity (cone angle is too small) working condition" is 0.10; the comparison results show that: when the "(b) cylindrical cavity + cone cavity" working condition has the same air cavity volume as the "(d) cylindrical cavity" working condition, the "b) cylindrical cavity + cone cavity" working condition weakens the vortex flow in the air cavity, that is, reduces the micro-vibration; under the "(b) cylindrical cavity + cone cavity" working condition, Compared with the "(c) cylindrical cavity + conical cavity (cone angle is too small)" working condition with the same cylindrical cavity size, the "b) cylindrical cavity + conical cavity working condition weakens the vortex flow in the air cavity, that is, reduces micro-vibration; compared with the vortex flow in the cavity of the "(c) cylindrical cavity + conical cavity (cone angle is too small)" working condition and the "(d) cylindrical cavity" working condition, in the "(b) cylindrical cavity + conical cavity" working condition, only separation bubbles exist in the air cavity, and no vortex flow is formed, which can make the supported part 1 operate more stably; compared with the "(a) no cavity" working condition, the "(b) cylindrical cavity + conical cavity" working condition improves the bearing capacity, among which the "(b) cylindrical cavity + conical cavity" working condition can provide a bearing capacity of 104.26N, and the "(a) no cavity" working condition can provide a bearing capacity of 50.70N.

[0030] Depend on Figure 2-Figure 4 It can be seen that compared with the working conditions of "(c) cylindrical cavity + conical cavity (cone angle is too small)" and "(d) cylindrical cavity", the working condition of "(b) cylindrical cavity + conical cavity" of the utility model limits the range of cone angle α to (60°-80°), which weakens the vortex flow; in addition, due to the existence of the air cavity, the working condition of "(b) cylindrical cavity + conical cavity" can provide an effective bearing capacity greater than that of "(a) no cavity" working condition.

[0031] The specific embodiments of the present invention are described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Various changes can be made within the knowledge of ordinary technicians in this field without departing from the purpose of the present invention.

Claims

1. A cavity small hole throttle for single hole throttling air static pressure support bearing, characterized in that: It includes a throttling hole, a conical air cavity, and a cylindrical air cavity. One end of the throttling hole is connected to the air supply channel, the other end of the throttling hole is connected to the thin end of the conical air cavity, and the thick end of the conical air cavity is connected to one end of the cylindrical air cavity.

2. The cavity small hole throttle for single hole throttling air static pressure support bearing according to claim 1, characterized in that: The cone angle of the conical air cavity at the outlet ranges from 60° to 80°.

3. The cavity small hole throttle for single hole throttling air static pressure support bearing according to claim 1, characterized in that: The ratio of the air volume of the conical air cavity to the air volume of the cylindrical air cavity is 1.5-2.

4. The cavity small hole throttle for single hole throttling air static pressure support bearing according to claim 1, characterized in that: The cavity volume is less than 5% of the total operating air volume composed of the air cavity and the air film; wherein the cavity volume is the total volume of the cylindrical air cavity and the conical air cavity, and the air cavity is the cylindrical air cavity + the conical air cavity.

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