Ultra-precision hydrostatic rotary table

Abstract

The application relates to an ultra-precision hydrostatic rotary table which comprises a first end cover, a main shaft, a bearing and a cylindrical rotary table shell; the first end cover is arranged at a first port of the rotary table shell; the bearing is coaxially arranged in the rotary table shell, and the first end surface of the bearing is attached to the first end cover; the main shaft is arranged in the central hole of the bearing, the first end of the main shaft is connected to the first end cover, and the second end of the main shaft is clamped on the second end surface of the bearing; an annular gap is arranged between the side wall of the bearing and the rotary table shell, the annular gap is sealed at the two ends in the axial direction of the bearing, and the annular gap is connected to an inlet on the rotary table shell; the bearing is distributed with conveying pipelines which respectively extend from the annular gap to the two end surfaces of the bearing and extend from the annular gap to the central hole of the bearing; working medium enters the annular gap from the inlet and is then conveyed to the two end surfaces of the bearing and the central hole of the bearing along the conveying pipelines. The rotary table has the advantages of simple overall structure, difficulty in blockage, easy processing and convenient maintenance.

Description

Technical Field

[0001] The present invention relates to the technical field of mechanical processing devices, in particular to an ultra-precision static pressure rotary table. Background Art

[0002] Ultra-precision CNC machine tools are important carriers for achieving precision machining of complex parts, thereby obtaining parts with high shape accuracy, surface accuracy and surface integrity. The machining accuracy of machine tools mainly depends on the performance of their key functional components. The rotary table in the machine tool is used to support and drive the workpiece to achieve rotational positioning. It cooperates with other components of the machine tool to achieve precision machining of parts, which is a key factor affecting the performance of the machine tool. An ultra-precision hydrostatic rotary table refers to a rotary table system that uses hydrostatic bearing support and has high rigidity and high rotational positioning accuracy. There is only fluid friction between the bearings and the work surface of the turntable, which has the advantages of low friction resistance, strong load-bearing capacity and high rigidity. At the same time, the load-bearing fluid film also has the effect of error averaging, which can improve the rotational positioning accuracy of the turntable.

[0003] Currently, existing rotary tables generally utilize a constant-pressure oil supply system. Bearings typically require external throttles (such as small orifice or capillary throttles) to regulate the pressure in each bearing oil chamber, thereby maintaining a balance between the oil chamber pressure and the external load. In practice, this throttling method requires the installation of an equal number of throttles on the turntable based on the number of oil chambers. This increases the complexity of the turntable structure and also poses issues such as throttle blockage and difficulty in maintenance.

[0004] When the existing rotary table is rotating, hydraulic oil will leak out from the gap between the work table and the bearing, which not only pollutes the internal environment of the machine tool, but also makes the oil supply system unable to recover the hydraulic oil, resulting in problems such as insufficient oil supply. Summary of the Invention

[0005] (1) Technical issues to be resolved

[0006] In view of the above-mentioned shortcomings and deficiencies of the prior art, the present invention provides an ultra-precision hydrostatic rotary table, which solves the technical problems of the existing rotary table such as complex oil supply structure, difficult maintenance, and easy leakage of hydraulic oil.

[0007] (2) Technical solution

[0008] In order to achieve the above objectives, the main technical solutions adopted by the present invention include:

[0009] In a first aspect, an embodiment of the present invention provides an ultra-precision hydrostatic rotary table, comprising a first end cover, a spindle, a bearing, and a cylindrical turntable housing;

[0010] The first end cover is arranged at the first port of the turntable housing;

[0011] The bearing is coaxially arranged in the turntable housing with the turntable housing, and the first end surface of the bearing is in contact with the first end cover;

[0012] The main shaft is inserted into the center hole of the bearing, the first end of the main shaft is connected to the first end cover, and the second end of the main shaft is clamped on the second end surface of the bearing;

[0013] An annular gap is provided between the side wall of the bearing and the turntable housing, the annular gap is sealed at both ends along the axial direction of the bearing, and the annular gap is connected to an inlet located on the turntable housing;

[0014] The bearing is provided with a delivery pipe extending from the annular gap to the two end surfaces of the bearing, and extending from the annular gap to the central hole of the bearing;

[0015] The working medium enters the annular gap from the inlet and is then transported along different delivery pipes to the two end faces of the bearing and the center hole of the bearing to form a medium film layer between the first end face of the bearing and the first end cover, between the second end face of the bearing and the second end of the main shaft, and between the center hole of the bearing and the side wall of the main shaft.

[0016] Optionally, in the ultra-precision hydrostatic rotary table, the delivery pipe connecting the annular gap and the first end face of the bearing is a first pipe, and there are multiple pairs of first pipes, and each pair of first pipes is symmetrically distributed with respect to the central axis of the bearing;

[0017] The delivery pipe connecting the annular gap and the second end surface of the bearing is a second pipe, and there are multiple pairs of second pipes, and each pair of second pipes is symmetrically distributed with respect to the central axis of the bearing;

[0018] The delivery pipe connecting the annular gap and the central hole of the bearing is a third pipe, and the third pipes are multiple pairs, and each pair of the third pipes is symmetrically distributed relative to the central axis of the bearing;

[0019] Ports of the first pipeline, the second pipeline, and the third pipeline connected to the annular gap are staggeredly distributed on the bearing side wall.

[0020] Optionally, in the ultra-precision hydrostatic rotary table, a plurality of first sub-oil chambers are distributed on the first end surface of the bearing, and the first pipes are connected to the first sub-oil chambers in a one-to-one manner;

[0021] A plurality of second sub-oil chambers are distributed on the second end surface of the bearing, and the second pipes are connected to the second sub-oil chambers one by one;

[0022] The first sub-oil chamber and the second sub-oil chamber are aligned one by one along the axial direction of the bearing;

[0023] A plurality of third sub-oil chambers are distributed on the side walls of the central hole of the bearing, and the third pipes are connected to the third sub-oil chambers one by one.

[0024] Optionally, the ultra-precision static pressure rotary table further includes an air-sealing structure;

[0025] The airtight sealing structure includes an air inlet, an air inlet channel and a first annular groove;

[0026] The outer side wall of the bearing is provided with an annular air inlet passage in a circumferential direction avoiding the annular gap;

[0027] The air inlet is provided on the turntable housing and is connected to the air inlet passage;

[0028] The first annular groove is provided on the first end surface of the bearing, and the first annular groove is provided on the outer side of the first sub-oil chamber in the radial direction of the bearing;

[0029] The air inlet channel is in communication with the first annular groove, and gas is transported into the first annular groove through the air inlet port and the air inlet channel, forming an airtight seal ring between the first end cover and the bearing.

[0030] Optionally, in the ultra-precision hydrostatic rotary table, the air-sealing structure further comprises a second annular groove, the second annular groove being concentrically arranged on the first end face of the bearing with the first annular groove;

[0031] The second annular groove is located between the first sub-oil chamber and the first annular groove, and the second annular groove is connected to the reflux groove located on the second end surface of the bearing;

[0032] The reflux groove is located on the outer side of the second sub-oil chamber along the radial direction of the bearing.

[0033] Optionally, the ultra-precision hydrostatic rotary table further comprises a spacer ring, wherein the spacer ring is coaxially embedded with the rotary table housing and is arranged on a side of the first end cover facing the main shaft;

[0034] The first end of the main shaft passes through the spacer ring and is connected to the first end cover, and the first end of the main shaft is clamped on the end surface of the spacer ring facing the main shaft;

[0035] The first end cover is sealedly connected to the first port of the turntable housing;

[0036] Optionally, the ultra-precision static pressure rotary table further includes a porous disc and a negative pressure channel;

[0037] The porous disc is arranged on the outside of the first end cover;

[0038] The negative pressure channel extends along the axis of the turntable housing, and the negative pressure channel sequentially passes through the first end cover and the main shaft to continuously provide negative pressure to the porous disc.

[0039] Optionally, for the ultra-precision static pressure rotary table, the porous disc is made of porous ceramic material, porous graphite material, or 3D printed porous metal material.

[0040] Optionally, the ultra-precision static pressure rotary table further includes a base sleeve, a rotation unit and an air suction pipeline;

[0041] The base sleeve is coaxial with the main shaft and is arranged on the end surface of the second end of the main shaft;

[0042] The rotating unit is arranged in the base sleeve;

[0043] The rotating unit includes an auxiliary rotating portion and an inner sleeve;

[0044] The inner sleeve is coaxial with the base sleeve and is rotatably disposed in the auxiliary rotating portion. The auxiliary rotating portion is fixed to the turntable housing, and the air intake pipe is disposed on the auxiliary rotating portion.

[0045] One end of the inner sleeve is sealed with the base sleeve, and the other end is rotatably sealed with the suction pipe;

[0046] The negative pressure channel extends from the second end of the main shaft, passes through the base sleeve and communicates with the inner sleeve.

[0047] Optionally, the ultra-precision static pressure rotary table further includes a motor stator and a motor rotor;

[0048] The motor rotor is sleeved on the outer side of the second end of the main shaft;

[0049] The motor stator is sleeved on the outer side of the motor rotor;

[0050] The motor stator is fixed on the turntable housing.

[0051] (3) Beneficial effects

[0052] The beneficial effects of the present invention are as follows: an ultra-precision hydrostatic rotary table of the present invention has an annular gap between the side wall of the bearing and the turntable housing, and the two ends of the annular gap along the axial direction of the bearing are sealed. The annular gap is connected to the inlet located on the turntable housing. At the same time, delivery pipes extending from the annular gap to the two end faces of the bearing and from the annular gap to the center hole of the bearing are distributed in the bearing. The working medium enters the annular gap from the inlet and is then delivered to the end faces of the bearing and the center hole of the bearing along different delivery pipes to perform radial and axial adjustment on the main shaft. Compared with the prior art, the assembly between the bearing and the turntable housing forms an annular slit as a throttling method for the hydrostatic rotary table. There is no need to install the same number of external throttles according to the number of oil chambers, which reduces the complexity of the bearing structure and simplifies the overall structure of the turntable. In addition, the throttling method of the annular surface slit is not easy to clog, is easy to process and convenient to maintain. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Figure 1 This is a three-dimensional schematic diagram of an ultra-precision hydrostatic rotary table according to embodiment 1 of the present invention;

[0054] Figure 2 for Figure 1 A top view of the ultra-precision hydrostatic rotary table;

[0055] Figure 3 for Figure 2 Schematic diagram of the cross section of the ultra-precision hydrostatic rotary table at AA;

[0056] Figure 4 for Figure 3 An enlarged schematic diagram of the ultra-precision hydrostatic rotary table at D;

[0057] Figure 5 for Figure 1 Schematic diagram of the working principle of the ultra-precision hydrostatic rotary table;

[0058] Figure 6 for Figure 3 Schematic cross-section of the ultra-precision hydrostatic rotary table at CC;

[0059] Figure 7 for Figure 6 Schematic cross-section of the ultra-precision hydrostatic rotary table at EE;

[0060] Figure 8 for Figure 7 An enlarged schematic diagram of the ultra-precision hydrostatic rotary table at F;

[0061] Figure 9 for Figure 7 An enlarged schematic diagram of the ultra-precision hydrostatic rotary table at G;

[0062] Figure 10 for Figure 3 A partially enlarged schematic diagram of the cross-sectional view of the ultra-precision hydrostatic rotary table at BB;

[0063] Figure 11 for Figure 3 Schematic cross-section of the ultra-precision hydrostatic rotary table at HH;

[0064] Figure 12 for Figure 7 Schematic cross-section diagram of the ultra-precision hydrostatic rotary table II;

[0065] Figure 13 for Figure 3 Schematic diagram of the ultra-precision hydrostatic rotary table bearing in Figure 1.

[0066] [Description of Reference Numerals]

[0067] 1: First end cover; 2: Main shaft; 3: Bearing; 31: Delivery pipeline; 311: First pipeline; 312: Second pipeline; 313: Third pipeline; 32: First sub-oil chamber; 33: Second sub-oil chamber; 34: Third sub-oil chamber; 36: Reflux groove; 4: Turntable housing; 5: Air sealing structure; 51: Air inlet; 52: Air inlet channel; 53: First annular groove; 54: Second annular groove; 6: Spacer ring; 7: Porous disk; 8: Negative pressure channel; 9: Base sleeve; 10: Rotating unit; 101: Auxiliary rotating part; 102: Inner sleeve; 11: Intake pipeline; 12: Motor stator; 13: Motor rotor; 14: Sensor bracket; 15: Sensor; 16: Encoder gear; 17: Fixed disk; 18: Adapter ring; 19: Water-cooled shell; 20: Second end cover; 21: Annular gap. DETAILED DESCRIPTION

[0068] An ultra-precision hydrostatic rotary table proposed in an embodiment of the present invention addresses technical problems of existing rotary tables, such as a complex oil supply structure, difficult maintenance, and easy leakage of hydraulic oil. An annular gap is provided between the side wall of the bearing and the turntable housing. The annular gap is sealed at both ends along the axial direction of the bearing. The annular gap is connected to an inlet located on the turntable housing. At the same time, delivery pipes are distributed in the bearing, extending from the annular gap to the two end faces of the bearing, and from the annular gap to the center hole of the bearing. The working medium enters the annular gap from the inlet and is then delivered to the end faces of the bearing and the center hole of the bearing along different delivery pipes to achieve radial and axial adjustment of the main shaft. Compared with the existing technology, the assembly between the bearing and the turntable housing forms an annular slit as a throttling method for the hydrostatic rotary table. There is no need to install the same number of external throttles according to the number of oil chambers, which reduces the complexity of the bearing structure and simplifies the overall structure of the turntable. In addition, the annular surface slit throttling method is not easy to clog, easy to process, and convenient to maintain.

[0069] To better understand the above technical solutions, exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments described herein. Instead, these embodiments are provided to enable a clearer and more thorough understanding of the present invention and to fully convey the scope of the present invention to those skilled in the art.

[0070] Example 1:

[0071] Reference Figure 1 、 Figure 2 and Figure 3 , this embodiment provides an ultra-precision hydrostatic rotary table, including a first end cover 1, a main shaft 2, a bearing 3 and a cylindrical turntable shell 4, and the first end cover 1 is arranged at the first port of the turntable shell 4. The bearing 3 and the turntable shell 4 are coaxially arranged in the turntable shell 4, and the first end face of the bearing 3 fits the first end cover 1, and a gap is retained between the two. The main shaft 2 is passed through the center hole of the bearing 3, and the first end of the main shaft 2 is connected to the first end cover 1, that is, the first end of the main shaft 2 is fixedly connected to the first end cover 1, so that the action force between the first end face of the bearing 3 and the first end cover 1 can be transmitted to the first end of the main shaft 2 along the axial direction of the main shaft 2. The second end of the main shaft 2 is clamped on the second end face of the bearing 3, as shown Figure 3 The second end of the main shaft 2 has a larger diameter than the first end, and the boss area formed is clamped and fits the second end face of the bearing 3. The second end face of the bearing 3 can directly transmit force to the second end of the main shaft 2 along the axial direction of the main shaft 2.

[0072] An annular gap 21 is defined between the sidewall of the bearing 3 and the turntable housing 4. The annular gap 21 is sealed at both ends of the bearing 3 along its axial direction and communicates with an inlet located on the turntable housing 4. A delivery conduit 31 is provided within the bearing 3, extending from the annular gap 21 to each of the two end faces of the bearing 3 and from the annular gap 21 to the center hole of the bearing 3.

[0073] Reference Figure 4 、 Figure 5 、 Figure 9 and Figure 10 The working medium enters the annular gap 21 through the inlet on the turntable housing 4 through the external pump body, and is then transported along different delivery pipes 31 to the two end faces of the bearing 3 and the center hole of the bearing 3, forming a medium film layer between the first end face of the bearing 3 and the first end cover 1, between the second end face of the bearing 3 and the second end of the main shaft 2, and between the center hole of the bearing 3 and the side wall of the main shaft 2. The medium film layer at the center hole of the bearing 3 forms a radial bearing capacity for the main shaft 2, and the medium film layer at the two end faces of the bearing 3 forms an axial bearing capacity for the main shaft 2, thereby exerting a stable radial and axial bearing effect on the main shaft 2. The working medium can be hydraulic oil or gas, with hydraulic oil being preferred.

[0074] By designing an annular gap 21 within the turntable housing 4 as a throttling mechanism for the bearing 3, instead of an external throttle, the problems of external throttles being prone to clogging and difficult to maintain are resolved. Furthermore, theoretically, the throttling structure of the annular gap 21 in this embodiment offers a wider adjustment range and simpler design than the aforementioned external throttle. This allows the turntable to have higher load-bearing capacity and rigidity under the same oil supply pressure, thereby improving the operating accuracy of the rotary table (hereinafter referred to as the turntable) while simplifying its overall structure.

[0075] Reference Figure 7 、 Figure 8 、 Figure 9 、 Figure 11 and Figure 12 , this embodiment provides an ultra-precision hydrostatic rotary table, the delivery pipe 31 connecting the annular gap 21 and the first end face of the bearing 3 is a first pipe 311, and there are multiple pairs of first pipes 311, and each pair of first pipes 311 is symmetrically distributed with respect to the central axis of the bearing 3. The delivery pipe 31 connecting the annular gap 21 and the second end face of the bearing 3 is a second pipe 312, and there are multiple pairs of second pipes 312, and each pair of second pipes 312 is symmetrically distributed with respect to the central axis of the bearing 3. The delivery pipe 31 connecting the annular gap 21 and the center hole of the bearing 3 is a third pipe 313, and there are multiple pairs of third pipes 313, and each pair of third pipes 313 is symmetrically distributed with respect to the central axis of the bearing 3. The pipes are distributed in a symmetrical manner, which is conducive to forming a more uniform dielectric film layer, refer to Figure 12The first and second conduits 311, 312 are located at the same height as the bearing 3, facilitating the flow of the working medium. The ports of the first, second, and third conduits 311, 312, 313, which connect to the annular gap 21, are staggered on the sidewall of the bearing 3. This facilitates the flow of the working medium from the annular gap 21 into the various delivery conduits 31 and improves the overall structural layout.

[0076] Reference Figure 8 、 Figure 9 and Figure 13 , this embodiment provides an ultra-precision hydrostatic rotary table, a plurality of first sub-oil chambers 32 are distributed on the first end face of the bearing 3, and the first pipe 311 is connected to the first sub-oil chamber 32 one-to-one. A plurality of second sub-oil chambers 33 are distributed on the second end face of the bearing 3, and the second pipe 312 is connected to the second sub-oil chamber 33 one-to-one. The first sub-oil chamber 32 and the second sub-oil chamber 33 are aligned one-to-one along the axial direction of the bearing 3, so that the two end faces of the bearing 3 can be subjected to balanced force with the participation of the working medium. A plurality of third sub-oil chambers 34 are distributed on the side wall of the center hole of the bearing 3, and the third pipe 313 is connected to the third sub-oil chamber 34 one-to-one. The sub-oil chambers correspond to the pipes one-to-one and are evenly distributed to ensure that the working medium forms a uniform film layer in different areas.

[0077] Reference Figure 1 、 Figure 3 、 Figure 4 and Figure 10 This embodiment provides an ultra-precision hydrostatic rotary table, which also includes an air-sealing structure 5. The air-sealing structure 5 includes an air inlet 51, an air inlet channel 52 and a first annular groove 53. An annular air inlet channel 52 is provided on the outer wall of the bearing 3 in the circumferential direction, avoiding the annular gap 21. The air inlet 51 is arranged on the turntable housing 4 and is connected to the air inlet channel 52 to allow gas to be introduced into the periphery of the bearing 3. The first annular groove 53 is arranged on the first end face of the bearing 3. The first annular groove 53 is arranged on the radial outside of the first sub-oil chamber 32 along the bearing 3. The air inlet channel 52 is connected to the first annular groove 53, and the two are connected through an air vent that passes through the inside of the bearing 3 along the axial direction of the bearing 3. A plurality of air vents can be provided to evenly distribute the gas in the first annular groove 53. The specific process is that gas is transported into the first annular groove 53 through the air inlet 51 and the air inlet channel 52 to form an air-sealing ring between the first end cover 1 and the bearing 3. The air-sealing ring can prevent the medium film layer formed in the first sub-oil chamber 32 from diffusing to the outer edge of the bearing 3, thereby preventing the working medium of the turntable from leaking out and extending the service life of the turntable.

[0078] Reference Figure 1 、 Figure 3This embodiment provides an ultra-precision hydrostatic rotary table. The air-sealing structure 5 further includes a second annular groove 54, which is concentrically arranged with the first annular groove 53 on the first end surface of the bearing 3. The second annular groove 54 is located between the first sub-oil chamber 32 and the first annular groove 53. The second annular groove 54 communicates with the reflux groove 36 located on the second end surface of the bearing 3. The reflux groove 36 is located radially outward of the second sub-oil chamber 33 in the bearing 3. The primary function of the second annular groove 54 is to facilitate the reflux of the working medium. The refluxed working medium is then transported to the exterior of the rotary table through the reflux groove 36 and an outlet (not labeled).

[0079] Reference Figure 1 and Figure 3 , this embodiment provides an ultra-precision hydrostatic rotary table, further comprising a spacer ring 6, which is coaxially embedded with the turntable housing 4 and arranged on the side of the first end cover 1 facing the main shaft 2. The first end of the main shaft 2 passes through the spacer ring 6 and is connected to the first end cover 1, and the first end of the main shaft 2 is clamped on the end face of the spacer ring 6 facing the main shaft 2. The size of the gap at the first end face of the bearing 3 can be adjusted by adjusting the thickness of the spacer ring 6. For example, by reducing the thickness of the spacer ring 6, the gap becomes smaller, and the thickness of the working medium film layer at the first end face of the bearing 3 is reduced, and vice versa. The first end cover 1 is sealed and connected to the first port of the turntable housing 4, as shown Figure 3 As shown, both use a labyrinth structure to achieve sealing. The labyrinth structure seal and the airtight seal structure 5 work together to prevent the turntable working medium from leaking out. At the same time, the gas can also flow outward through the gaps in the labyrinth structure, so that external impurities cannot enter the turntable, thereby increasing the service life of the turntable.

[0080] Reference Figure 1 、 Figure 3 and Figure 7 This embodiment provides an ultra-precision static pressure rotary table, further comprising a porous disc 7 and a negative pressure channel 8. The porous disc 7 is disposed outside the first end cap 1 via an annular fixed disc 17, which is fixedly connected to the first end cap 1. The negative pressure channel 8 extends along the axis of the rotary table housing 4, sequentially penetrating the first end cap 1 and the spindle 2 to continuously provide negative pressure to the porous disc 7.

[0081] The porous disc 7 is made of a porous material and maintains vacuum absorption during the turntable's rotation, firmly adhering the workpiece to the turntable. This allows the turntable to securely mount the workpiece without damaging it, allowing it to precisely machine the workpiece in conjunction with other machine tool components. Specifically, the porous disc 7 can be made of porous ceramic, porous graphite, or 3D-printed porous metal.

[0082] Reference Figure 1 、 Figure 3 、 Figure 6 and Figure 7This embodiment provides an ultra-precision static pressure rotary table, which also includes a base sleeve 9, a rotating unit 10, and an air intake pipe 11. The base sleeve 9 is coaxially arranged with the main shaft 2 on the end surface of the second end of the main shaft 2. The rotating unit 10 is arranged in the base sleeve 9 and includes an auxiliary rotating part 101 and an inner sleeve 102. The inner sleeve 102 is coaxially arranged with the base sleeve 9 and is rotatably arranged in the auxiliary rotating part 101. The auxiliary rotating part 101 is fixed to the turntable housing 4. The auxiliary rotating part 101 plays a role similar to the bearing 3, providing support for the inner sleeve 102 to rotate with the main shaft 2. The air intake pipe 11 is arranged on the auxiliary rotating part 101. One end of the inner sleeve 102 is sealed with the base sleeve 9, and the other end is rotatably and sealedly connected to the air intake pipe 11. The negative pressure channel 8 extends from the second end of the main shaft 2 through the base sleeve 9 and communicates with the inner sleeve 102. In this way, negative pressure is provided to the rotating inner sleeve 102 and the negative pressure channel 8 through the suction pipe 11 , thereby providing negative pressure to the porous disk 7 .

[0083] Reference Figure 1 、 Figure 3 and Figure 7 This embodiment provides an ultra-precision static pressure rotary table, which also includes a motor stator 12 and a motor rotor 13. The motor rotor 13 is sleeved on the outside of the second end of the main shaft 2, and the motor stator 12 is sleeved on the outside of the motor rotor 13. The motor stator 12 is fixed on the turntable housing 4.

[0084] Here, the motor stator 12 is externally mounted with a water-cooling housing 19 and then secured to the turntable housing 4 via an interference fit. The motor stator 12 and motor rotor 13 are mounted at the same center height, with a 1-3 mm gap between them for non-contact. When connected to a power source, the motor stator 12 drives the motor rotor 13 to rotate, which in turn drives the connected spindle 2 and other components that rotate synchronously with the spindle 2. Finally, a second end cap 20 is screwed onto the bottom of the turntable housing 4, sealed with an O-ring. The motor rotor 13 and spindle 2 are connected via an adapter ring 18.

[0085] An encoder gear 16 is installed at the bottom of the base sleeve 9, and the sensor 15 is installed on the sensor bracket 14. The sensor bracket 14 is installed on the turntable housing 4 by screws, and together they constitute a rotary positioning assembly. The sensor 15 provides feedback on the spindle speed and positioning information read by the encoder gear 16.

[0086] It should be noted that the thickness of the fine-tuning spacer ring 6 can change the working medium resistance and thus change the working pressure of the working medium film layer. The thinner the working medium film layer, the greater the working medium resistance, and the greater the working pressure at the corresponding bearing end face sub-oil chamber; the working medium resistance can also be changed by adjusting the thickness of the annular gap 21, thereby changing the working pressure of the working medium film layer. The greater the thickness of the annular gap 21, the smaller the working medium resistance in the annular gap 21, and the greater the working pressure at the corresponding bearing sub-oil chamber; or the working pressure of the bearing 3 (that is, the working pressure of the surrounding medium) can be directly changed by adjusting the initial pressure of the external pump body on the working medium.

[0087] In addition, regarding the ultra-precision hydrostatic rotary table in the present invention, for structures that have not been described in detail, please refer to the prior art unless they conflict with this solution.

[0088] In the description of the present invention, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of the technical features indicated. Therefore, a feature specified as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, "plurality" means two or more, unless otherwise specifically defined.

[0089] In the present invention, unless otherwise expressly specified or limited, the terms "mounted," "connected," "connect," "fixed," etc. should be understood broadly. For example, they may refer to fixed connection, detachable connection, or integration; mechanical connection or electrical connection; direct connection or indirect connection through an intermediate medium; and internal communication between two components or interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0090] In the present invention, unless otherwise expressly specified or limited, when a first feature is "above" or "below" a second feature, it may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. Furthermore, when a first feature is "above," "above," or "above" a second feature, it may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is at a higher level than the second feature. When a first feature is "below," "below," or "below" a second feature, it may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is at a lower level than the second feature.

[0091] In the description of this specification, the terms "one embodiment", "some embodiments", "embodiments", "examples", "specific examples" or "some examples" refer to the specific features, structures, materials or characteristics described in conjunction with the embodiment or example and included in at least one embodiment or example of the present invention. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine different embodiments or examples described in this specification and features of different embodiments or examples, unless they are mutually inconsistent.

[0092] Although the embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are illustrative and are not to be construed as limitations on the present invention. A person skilled in the art may alter, modify, replace and modify the above embodiments within the scope of the present invention.

Claims

1. An ultra-precision static pressure rotary table, characterized in that: It includes a first end cover, a main shaft, a bearing, a cylindrical turntable housing and an airtight sealing structure; The first end cover is arranged at the first port of the turntable housing; the bearing is coaxial with the turntable housing, the bearing is arranged in the turntable housing, and the first end surface of the bearing is in contact with the first end cover; The main shaft is arranged in the center hole of the bearing, the first end of the main shaft is connected to the first end cover, and the second end of the main shaft is clamped on the second end surface of the bearing; an annular gap is provided between the side wall of the bearing and the turntable housing, the annular gap is sealed at both ends along the axial direction of the bearing, and the annular gap is connected to the inlet of the turntable housing; The bearing is provided with a delivery pipe extending from the annular gap to the two end surfaces of the bearing, and extending from the annular gap to the central hole of the bearing; The working medium enters the annular gap from the inlet and is then transported along the different delivery pipes to the two end faces of the bearing and the center hole of the bearing, so as to form a medium film layer between the first end face of the bearing and the first end cover, between the second end face of the bearing and the second end of the main shaft, and between the center hole of the bearing and the side wall of the main shaft; A plurality of first sub-oil chambers are evenly distributed on the first end surface of the bearing, and a plurality of second sub-oil chambers are evenly distributed on the second end surface of the bearing; The airtight sealing structure includes an air inlet, an air inlet channel, a first annular groove and a second annular groove; The outer wall of the bearing is provided with an air intake passage in a circumferential direction avoiding the annular gap, and the air intake passage is annular; The air inlet is provided on the turntable housing and is connected to the air inlet passage; The first annular groove is provided on the first end surface of the bearing, and the first annular groove is provided on the outer side of the first sub-oil chamber in the radial direction of the bearing; The air inlet channel is in communication with the first annular groove, and gas is transported into the first annular groove through the air inlet port and the air inlet channel, forming an airtight seal ring between the first end cover and the bearing; The second annular groove is concentrically arranged on the first end surface of the bearing with the first annular groove; The second annular groove is located between the first sub-oil chamber and the first annular groove, and the second annular groove is connected to the reflux groove on the second end surface of the bearing; The reflux groove is located on the outer side of the second sub-oil chamber along the radial direction of the bearing.

2. The ultra-precision hydrostatic rotary table according to claim 1, characterized in that: The delivery pipe connecting the annular gap and the first end surface of the bearing is a first pipe, and there are multiple pairs of first pipes, and each pair of first pipes is symmetrically distributed with respect to the central axis of the bearing; The delivery pipe connecting the annular gap and the second end surface of the bearing is a second pipe, and there are multiple pairs of second pipes, and each pair of second pipes is symmetrically distributed with respect to the central axis of the bearing; The delivery pipe connecting the annular gap and the central hole of the bearing is a third pipe, and the third pipes are multiple pairs, and each pair of the third pipes is symmetrically distributed relative to the central axis of the bearing; Ports of the first pipeline, the second pipeline, and the third pipeline connected to the annular gap are staggeredly distributed on the bearing side wall.

3. The ultra-precision static pressure rotary table according to claim 2, characterized in that: The first pipe is connected to the first sub-oil chamber in a one-to-one manner; The second pipeline is connected to the second sub-oil chamber in a one-to-one manner; The first sub-oil chamber and the second sub-oil chamber are aligned one by one along the axial direction of the bearing; A plurality of third sub-oil chambers are evenly distributed on the side wall of the central hole of the bearing, and the third pipes are connected to the third sub-oil chambers one by one.

4. The ultra-precision hydrostatic rotary table according to claim 1, characterized in that: It also includes a spacer ring, which is coaxially embedded with the turntable housing and arranged on a side of the first end cover facing the main shaft; The first end of the main shaft passes through the spacer ring and is connected to the first end cover, and the first end of the main shaft is clamped on the end surface of the spacer ring facing the main shaft; The first end cover is sealed to the first port of the turntable housing.

5. The ultra-precision hydrostatic rotary table according to claim 1, characterized in that: Also included are a porous disc and negative pressure channels; The porous disc is arranged on the outside of the first end cover; The negative pressure channel extends along the axis of the turntable housing, and the negative pressure channel sequentially passes through the first end cover and the main shaft to continuously provide negative pressure to the porous disc.

6. The ultra-precision static pressure rotary table according to claim 5, characterized in that: The porous disc is made of any one of porous ceramic material, porous graphite material, and 3D printed porous metal material.

7. The ultra-precision static pressure rotary table according to claim 5, characterized in that: It also includes a base sleeve, a rotating unit and an air suction line; The base sleeve is coaxial with the main shaft and is arranged on the end surface of the second end of the main shaft; The rotating unit is arranged in the base sleeve; The rotating unit includes an auxiliary rotating portion and an inner sleeve; The inner sleeve is coaxial with the base sleeve and is rotatably disposed in the auxiliary rotating portion. The auxiliary rotating portion is fixed to the turntable housing, and the air intake pipe is disposed on the auxiliary rotating portion. One end of the inner sleeve is sealed with the base sleeve, and the other end is rotatably sealed with the suction pipe; The negative pressure channel extends from the second end of the main shaft, passes through the base sleeve and communicates with the inner sleeve.

8. The ultra-precision hydrostatic rotary table according to claim 1, characterized in that: Also includes a motor stator and a motor rotor; The motor rotor is sleeved on the outer side of the second end of the main shaft; The motor stator is sleeved on the outer side of the motor rotor; The motor stator is fixed on the turntable housing.

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