Ultra-precise static pressure rotating table

Abstract

The invention relates to an ultra-precise static pressure 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 and the rotary table shell are coaxially arranged in the rotary table shell, and the first end face of the bearing is attached to the first end cover. The main shaft penetrates through a 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 to the second end face of the bearing. An annular gap is formed between the side wall of the bearing and the rotary table shell, the two ends, in the axial direction of the bearing, of the annular gap are sealed, and the annular gap communicates with an inlet located in the rotary table shell. Conveying pipelines which respectively extend to two end surfaces of the bearing from the annular gap and extend to a central hole of the bearing from the annular gap are distributed in the bearing; working media enter the annular gap from the inlet and then are conveyed to the two end faces of the bearing and the center hole of the bearing along the conveying pipeline. The rotary table has the beneficial effects of simplifying the overall structure of the rotary table, being not easy to block, being easy to process and being convenient to maintain.

Description

Technical Field

[0001] The invention relates to the technical field of mechanical processing devices, and 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. The ultra-precision hydrostatic rotary table refers to a rotary table system that adopts hydrostatic bearing support, 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] At present, the existing rotary table generally adopts the constant pressure oil supply method, and the bearing usually needs to use an external throttle (such as a small hole or capillary throttle, etc.) to adjust the pressure in each oil chamber of the bearing, so as to maintain the balance between the oil chamber pressure and the external load. In actual application, the above throttling method requires the same number of throttles to be installed on the turntable according to the number of oil chambers, which increases the complexity of the turntable structure. At the same time, there are also problems such as easy blockage and difficult maintenance of the throttle.

[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] (II) Technical solution

[0008] In order to achieve the above object, 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 rotary table housing;

[0010] The first end cover is disposed 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 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;

[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 pipeline extending from the annular gap to 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 surfaces of the bearing and the center hole of the bearing to form a medium film layer between the first end surface of the bearing and the first end cover, between the second end surface 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 surface of the bearing is a first pipe, and there are multiple pairs of the first pipes, and each pair of the first pipes is symmetrically distributed relative to the central axis of the bearing;

[0017] The delivery pipeline connecting the annular gap and the second end surface of the bearing is a second pipeline, and the second pipelines are multiple pairs, and each pair of the second pipelines is symmetrically distributed relative to the central axis of the bearing;

[0018] The delivery pipeline connecting the annular gap and the central hole of the bearing is a third pipeline, and the third pipelines are multiple pairs, and each pair of the third pipelines 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 distributed alternately on the side wall of the bearing.

[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 pipelines are connected to the first sub-oil chambers one by one;

[0021] A plurality of second sub-oil chambers are evenly 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 center hole of the bearing, and the third pipelines 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 air-sealing structure comprises an air inlet, an air inlet passage and a first annular groove;

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

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

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

[0029] The air inlet passage 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 passage, so as to form an air sealing ring between the first end cover and the bearing.

[0030] Optionally, in the ultra-precision static pressure rotary table, the air sealing structure further comprises a second annular groove, and the second annular groove is arranged concentrically with the first annular groove on the first end surface of the bearing;

[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 static pressure rotary table further comprises a spacer ring, wherein the spacer ring is coaxially embedded with the rotary table housing and 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 sealed and 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 outside 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, in 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 rotating unit and an air suction pipeline;

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

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

[0043] The rotating unit comprises an auxiliary rotating part and an inner sleeve;

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

[0045] One end of the inner sleeve is sealed and connected to the base sleeve, and the other end is rotatably and sealedly connected to the air intake pipeline;

[0046] The negative pressure channel extends from the second end of the main shaft 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] (III) 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, and the annular gap is connected to the inlet located on the turntable housing. At the same time, there are 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 in the bearing. The working medium enters the annular gap from the inlet, and then is delivered to the end face 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 of the hydrostatic rotary table, and there is no need to install the same number of external throttling devices 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 be blocked, easy to process and convenient to maintain. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Figure 1 It is a three-dimensional schematic diagram of an ultra-precision static pressure rotary table of Example 1 of an ultra-precision static pressure rotary table 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 The cross-sectional diagram 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 diagram of the cross section of the ultra-precision hydrostatic rotary table at CC;

[0059] Figure 7 for Figure 6 Schematic diagram of the 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] Fig. 9 for Figure 7 An enlarged schematic diagram of the ultra-precision hydrostatic rotary table at G;

[0062] Fig.10 for Figure 3 A partial enlarged schematic diagram of the cross-sectional schematic diagram of the ultra-precision static pressure rotary table at BB;

[0063] Fig.11 for Figure 3 A schematic cross-sectional view of the ultra-precision hydrostatic rotary table at HH;

[0064] Fig.12 for Figure 7 A cross-sectional diagram of the ultra-precision hydrostatic rotary table II;

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

[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 shell; 5: air sealing structure; 51: air inlet; 52: air inlet channel; 53: first annular groove; 54: second annular groove; 6: spacer ring; 7: porous disc; 8: negative pressure channel; 9: base sleeve; 10: rotating unit; 101: auxiliary rotating part; 102: inner sleeve; 11: suction pipeline; 12: motor stator; 13: motor rotor; 14: sensor bracket; 15: sensor; 16: encoder gear; 17: fixed disk; 18: adapter ring; 19: water-cooling 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 is designed to solve the technical problems of the existing rotary table, such as the complicated 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 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, there are 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. The working medium enters the annular gap from the inlet and is then delivered to the end face of the bearing and the center hole of the bearing along different delivery pipes to adjust the main shaft radially and axially. Compared with the prior art, the assembly between the bearing and the turntable housing forms an annular slit as a throttling method of the hydrostatic rotary table. There is no need to install the same number of external throttling devices 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 be blocked, easy to process and convenient to maintain.

[0069] In order to better understand the above technical solution, 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. On the contrary, 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] Embodiment 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, wherein 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 reserved therebetween. 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 in FIG. Figure 3 The second end of the main shaft 2 has a larger diameter than the first end, and the formed boss area is snap-fitted to 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 provided between the side wall of the bearing 3 and the turntable housing 4. The annular gap 21 is sealed at both ends of the axial direction of the bearing 3, and the annular gap 21 is connected to the inlet located on the turntable housing 4. A delivery pipeline 31 extending from the annular gap 21 to the two end surfaces of the bearing 3 and from the annular gap 21 to the center hole of the bearing 3 is distributed in the bearing 3.

[0073] Reference Figure 4 , Figure 5 , Fig. 9 and Fig.10 , the working medium enters the annular gap 21 from the inlet on the turntable housing 4 through the external pump body, and is then transported to the two end faces of the bearing 3 and the center hole of the bearing 3 along different delivery pipes 31, so as to form 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 force for the main shaft 2, and the medium film layer at the two end faces of the bearing 3 forms an axial bearing force for the main shaft 2, thereby playing a role in stabilizing the radial and axial bearing of the main shaft 2. Among them, the working medium can be selected from hydraulic oil or gas, preferably hydraulic oil.

[0074] By designing an annular gap 21 inside the turntable housing 4 to replace the external throttle as the throttling method of the bearing 3, the problem of the external throttle being easily blocked and difficult to repair is solved. At the same time, in theoretical calculation, the throttling structure of the annular gap 21 in this embodiment has a larger adjustment range than the external throttle mentioned above, and is simpler in design. Under the same oil supply pressure, the turntable can have a higher bearing capacity and rigidity, thereby improving the working accuracy of the rotary table (hereinafter referred to as the turntable), and simplifying the overall structure of the turntable.

[0075] Reference Figure 7 , Figure 8 , Fig. 9 , Fig.11 and Fig.12 The present embodiment provides an ultra-precision static pressure rotary table, wherein the delivery pipe 31 connecting the annular gap 21 and the first end surface 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 surface 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 Fig.12The first pipeline 311 and the second pipeline 312 are distributed at the same height of the bearing 3, which is convenient for the working medium to flow in. The ports of the first pipeline 311, the second pipeline 312 and the third pipeline 313 connected to the annular gap 21 are staggered on the side wall of the bearing 3, which is convenient for the working medium to flow from the annular gap 21 into different delivery pipelines 31, and is also beneficial to the overall structural layout.

[0076] Reference Figure 8 , Fig. 9 and Fig.13 The present embodiment provides an ultra-precision static pressure rotary table, wherein a plurality of first sub-oil chambers 32 are evenly distributed on the first end surface 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 evenly distributed on the second end surface 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 with the axial direction of the bearing 3, so that the two end surfaces of the bearing 3 can be balanced with the participation of the working medium. A plurality of third sub-oil chambers 34 are evenly 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 Fig.10 The present embodiment provides an ultra-precision hydrostatic rotary table, further comprising an air sealing structure 5, the air sealing structure 5 comprising 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 circumferentially 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 a circle of the bearing 3. The first annular groove 53 is arranged on the first end face of the bearing 3, and the first annular groove 53 is arranged on the outer side of the first sub-oil chamber 32 along the radial direction of 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 may 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 toward 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 static pressure rotary table, and the air sealing structure 5 also includes a second annular groove 54, which is concentrically arranged on the first end face of the bearing 3 with the first annular groove 53. The second annular groove 54 is located between the first sub-oil chamber 32 and the first annular groove 53, and the second annular groove 54 is connected to the reflux groove 36 located at the second end face of the bearing 3, and the reflux groove 36 is located on the radial outer side of the second sub-oil chamber 33 along the bearing 3. The second annular groove 54 mainly assists the reflux of the working medium, and the refluxed working medium is transported to the outside of the rotary table through the reflux groove 36 and the outlet (not marked in the figure).

[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, such as Figure 3 As shown, both use a labyrinth structure to achieve sealing. The labyrinth structure seal and the air sealing structure 5 work together to prevent the turntable working medium from leaking out. At the same time, the gas can 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, which also includes a porous disc 7 and a negative pressure channel 8. The porous disc 7 is arranged outside the first end cover 1 through an annular fixed disc 17, and the fixed disc 17 is fixedly connected to the first end cover 1. The negative pressure channel 8 extends along the axis of the rotary table housing 4, and the negative pressure channel 8 sequentially penetrates the first end cover 1 and the main shaft 2 to continuously provide negative pressure to the porous disc 7.

[0081] The porous disc 7 is made of porous material, and can still maintain vacuum adsorption when the turntable rotates, firmly adsorbing the workpiece to be processed on the turntable, so that the turntable can install the workpiece to be processed without damage, and cooperate with other parts of the machine tool to perform precision processing on the workpiece. Specifically, the porous disc 7 is made of porous ceramic material, porous graphite material, and 3D printed metal porous material.

[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 suction pipeline 11. The base sleeve 9 is coaxially arranged on the end surface of the second end of the main shaft 2 with the main shaft 2. The rotating unit 10 is arranged in the base sleeve 9, and the rotating unit 10 includes an auxiliary rotating part 101 and an inner sleeve 102. The inner sleeve 102 is coaxially arranged with the base sleeve 9, and the inner sleeve 102 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 suction pipeline 11 is arranged on the auxiliary rotating part 101. One end of the inner sleeve 102 is sealed and connected to the base sleeve 9, and the other end is rotatably and sealedly connected to the air suction pipeline 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 The present 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 outer side of the second end of the main shaft 2, and the motor stator 12 is sleeved on the outer side 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 fixed to the turntable housing 4 by interference fit. The motor stator 12 and the motor rotor 13 are mounted at the same center height, with a 1-3 mm gap and no contact between them. After the motor stator 12 is connected to the power supply, it drives the motor rotor 13 to rotate, and the motor rotor 13 drives the main shaft 2 connected to it and other components that rotate synchronously with the main shaft 2 to rotate. Finally, the second end cover 20 is installed at the bottom of the turntable housing 4 by screws, and an O-ring is used to seal the bottom of the turntable. The motor rotor 13 and the main shaft 2 are connected by an adapter ring 18.

[0085] An encoder gear 16 is installed at the bottom of the base sleeve 9, and a sensor 15 is installed on a 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 information such as the spindle speed and positioning read by the encoder gear 16.

[0086] It should be noted that fine-tuning the thickness of the 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 (i.e., 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 if they do not 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 as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0089] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0090] In the present invention, unless otherwise clearly specified and limited, when a first feature is “on” or “below” a second feature, it may be 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. Moreover, when a first feature is “above”, “above” or “above” a second feature, it may be that the first feature is directly above or obliquely above the second feature, or it may simply mean that the first feature is higher in level than the second feature. When a first feature is “below”, “below” or “below” a second feature, it may be that the first feature is directly below or obliquely below the second feature, or it may simply mean that the first feature is lower in level than the second feature.

[0091] In the description of this specification, the description of the terms "one embodiment", "some embodiments", "embodiment", "example", "specific example" or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations 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 the different embodiments or examples described in this specification and the features of the different embodiments or examples, unless they are contradictory.

[0092] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of 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, It is characterized in that It comprises a first end cover, a main shaft, a bearing and a cylindrical turntable housing; the first end cover is arranged at the first port of the turntable housing; 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; The main shaft is inserted into 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 provided between the side wall of the bearing and the turntable housing, the annular gap is sealed at both ends of the bearing axial direction, and the annular gap is connected to the inlet located on the turntable housing; The bearing is provided with a delivery pipeline extending from the annular gap to 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 different delivery pipes to the two end surfaces of the bearing and the center hole of the bearing to form a medium film layer between the first end surface of the bearing and the first end cover, between the second end surface 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.

2. The ultra-precision static pressure rotary table according to claim 1, It is characterized in that The delivery pipeline connecting the annular gap and the first end surface of the bearing is a first pipeline, and the first pipelines are multiple pairs, and each pair of the first pipelines is symmetrically distributed relative to the central axis of the bearing; The delivery pipeline connecting the annular gap and the second end surface of the bearing is a second pipeline, and the second pipelines are multiple pairs, and each pair of the second pipelines is symmetrically distributed relative to the central axis of the bearing; The delivery pipeline connecting the annular gap and the central hole of the bearing is a third pipeline, and the third pipelines are multiple pairs, and each pair of the third pipelines 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 distributed alternately on the side wall of the bearing.

3. The ultra-precision static pressure rotary table according to claim 2, It is characterized in that 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 one by one; A plurality of second sub-oil chambers are evenly distributed on the second end surface of the bearing, and the second pipes are connected to the second sub-oil chambers one by one; 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 distributed on the side walls of the center hole of the bearing, and the third pipelines are connected to the third sub-oil chambers one by one.

4. The ultra-precision static pressure rotary table according to claim 3, It is characterized in that Also included is an airtight structure; The air-sealing structure comprises an air inlet, an air inlet passage and a first annular groove; The outer wall of the bearing is provided with an annular air inlet passage in a circumferential direction away from the annular gap; The air inlet is arranged on the turntable housing and is connected to the air inlet passage; The first annular groove is arranged on the first end surface of the bearing, and the first annular groove is arranged on the outer side of the first sub-oil chamber along the radial direction of the bearing; The air inlet passage 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 passage, so as to form an air sealing ring between the first end cover and the bearing.

5. The ultra-precision static pressure rotary table according to claim 4, It is characterized in that The air sealing structure further comprises a second annular groove, which is arranged concentrically with the first annular groove on the first end surface of the bearing; 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; The reflux groove is located on the outer side of the second sub-oil chamber along the radial direction of the bearing.

6. The ultra-precision static pressure rotary table according to claim 1, It is 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 and connected to the first port of the turntable housing.

7. The ultra-precision static pressure rotary table according to claim 1, It is characterized in that Also included are a porous disc and a negative pressure channel; The porous disc is arranged outside 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.

8. The ultra-precision static pressure rotary table according to claim 7, It is characterized in that The porous disc is made of porous ceramic material, porous graphite material, or 3D printed porous metal material.

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

10. The ultra-precision static pressure rotary table according to claim 1, It is 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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