Precise air floating turntable

Abstract

The present application relates to air floating turntable technical field, specifically disclose a kind of precision air floating turntable, the precision air floating turntable includes mounting seat, drive assembly, air bearing rotor and air bearing stator. Wherein, drive assembly is screwed in mounting seat, air bearing rotor is connected to the output end of drive assembly;Air bearing rotor's end portion is equipped with adapter disk, adapter disk and air bearing rotor are enclosed into annular groove, adapter disk is equipped with first through-hole;Air bearing stator is screwed in mounting seat, air bearing stator is equipped with positive pressure component and negative pressure component, positive pressure component includes at least one positive pressure inlet, positive pressure inlet is used to provide positive pressure gas, positive pressure gas is generated gas film on the upper end surface, lower end surface of air bearing stator and the inner surface located in the circumferential direction of air bearing rotor.The above-mentioned setting, so that the upper end surface, lower end surface and inner side of air bearing stator can generate gas film, in turn avoid and air bearing rotor rub, improve the rotation accuracy of air bearing rotor.

Description

Technical Field

[0001] This invention relates to the field of air-bearing turntable technology, and more particularly to a precision air-bearing turntable. Background Technology

[0002] A rotary table, as the worktable of a machine tool, can be rotated to any position and fixed in that position. Currently, most rotary table structures have coaxial mechanical bearing inner and outer rings mounted on the base. The outer ring provides support, while one end of the inner ring is connected to the drive assembly, and the other end is connected to the support platform.

[0003] However, the turntable with the above structure limits the runout of the platform end face and radial runout to the bearings, making it impossible to achieve higher precision. Summary of the Invention

[0004] The purpose of this invention is to provide a precision air-bearing turntable that avoids the use of mechanical bearings, thereby achieving higher precision.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] This invention provides a precision air-bearing turntable, which includes:

[0007] Mounting base;

[0008] The drive component is located on the mounting base.

[0009] An air bearing rotor is connected to the output end of the drive assembly;

[0010] A transfer plate is provided at the end of the air bearing rotor. The transfer plate and the air bearing rotor form an annular groove. The transfer plate is provided with a first through hole.

[0011] An air bearing stator is provided on the mounting base, and the lower end face of the air bearing stator is parallel to the lower side of the annular groove, a portion of the upper end face of the air bearing stator is parallel to the upper side of the annular groove, and the inner surface of the air bearing stator is arranged around the circumference of the air bearing rotor.

[0012] A positive pressure assembly includes at least one positive pressure inlet for providing positive pressure gas, which generates a gas film on the upper and lower end faces of the air bearing stator and on the inner surface of the air bearing rotor circumferentially.

[0013] As a preferred embodiment of a precision air-bearing turntable, the positive pressure assembly further includes a partial positive pressure channel, a first positive pressure channel, a second positive pressure channel, and a third positive pressure channel. The positive pressure inlet is connected to the partial positive pressure channel. The first positive pressure channel is connected between the partial positive pressure channel and a throttling orifice on the upper end face of the air-bearing stator. The second positive pressure channel is connected between the partial positive pressure channel and a throttling orifice on the lower end face of the air-bearing stator. The third positive pressure channel is connected between the partial positive pressure channel and a throttling orifice on the inner surface of the air-bearing stator.

[0014] As a preferred embodiment of a precision air-bearing turntable, the precision air-bearing turntable further includes a negative pressure assembly, which includes at least one negative pressure inlet for providing negative pressure gas. The negative pressure gas passes through the air-bearing stator and communicates with the first through hole.

[0015] As a preferred embodiment of a precision air-bearing turntable, the negative pressure assembly further includes a negative pressure inlet channel, a first negative pressure channel, and a negative pressure annular groove; the negative pressure inlet channel and the negative pressure inlet are connected to the first negative pressure channel, the negative pressure annular groove is disposed on the upper end face of the air-bearing stator, the first negative pressure channel is connected between the negative pressure inlet channel and the negative pressure annular groove, and the negative pressure annular groove is connected to the first through hole.

[0016] As a preferred embodiment of a precision air-bearing turntable, the precision air-bearing turntable further includes an isolation component, which is used to separate the positive pressure gas on the upper end face of the air-bearing stator from the negative pressure gas passing through the air-bearing stator, to separate the positive pressure gas on the upper end face and inner surface of the air-bearing stator, and to separate the positive pressure gas on the lower end face and inner surface of the air-bearing stator.

[0017] As a preferred embodiment of a precision air-bearing turntable, the first negative pressure channel penetrates the upper and lower end faces of the air-bearing bearing stator; the isolation assembly includes a first atmospheric annular groove on the upper end face of the air-bearing bearing stator, a second atmospheric annular groove between the mounting base and the air-bearing bearing rotor, a third atmospheric annular groove on the lower end face of the transfer plate, and a fourth atmospheric annular groove at the junction of the lower end face of the air-bearing bearing stator and the inner surface of the air-bearing bearing stator. The first atmospheric annular groove is located between the throttling orifice on the upper end face of the air-bearing bearing stator and the negative pressure annular groove; the second atmospheric annular groove is located between the throttling orifice on the lower end face of the air-bearing bearing stator and the inlet of the first negative pressure channel; the third atmospheric annular groove is located at the junction connecting the upper end face of the air-bearing bearing stator and the inner surface of the air-bearing bearing stator; the first, second, third, and fourth atmospheric annular grooves are all in communication with the external environment.

[0018] As a preferred embodiment of a precision air-bearing turntable, the drive assembly includes a motor rotor and a motor stator, the motor rotor and the motor stator having a through-cavity, the motor stator being fixed to the mounting base, and the motor rotor being sleeved on the air-bearing rotor.

[0019] As a preferred embodiment of a precision air-bearing turntable, the precision air-bearing turntable further includes a fixing component, which is disposed on the air-bearing rotor. The air-bearing rotor is provided with a support platform, one end of the motor rotor abuts against the support platform, and the other end abuts against the fixing component.

[0020] As a preferred embodiment of a precision air-bearing turntable, the precision air-bearing turntable further includes a grating and a support member. The support member is disposed on the air-bearing rotor, the grating has a through-hole, the grating is sleeved on the air-bearing rotor, and fixed to the support member.

[0021] As a preferred embodiment of a precision air-bearing turntable, the precision air-bearing turntable further includes a heat dissipation component for dissipating heat from the drive component.

[0022] The beneficial effects of this invention are as follows:

[0023] This invention provides a precision air-bearing turntable for high-precision wafer inspection in the semiconductor industry. The precision air-bearing turntable includes a mounting base, a drive assembly, an air-bearing rotor, and an air-bearing stator. The drive assembly is screwed to the mounting base, and the air bearing rotor is connected to the output end of the drive assembly. The end of the air bearing rotor is provided with a transfer plate, which, together with the air bearing rotor, forms an annular groove. The transfer plate has a first through hole. The air bearing stator is screwed to the mounting base, with a portion of the lower end face of the air bearing stator parallel to the lower side of the annular groove, and a portion of the upper end face of the air bearing stator parallel to the upper side of the annular groove. The inner surface of the air bearing stator is arranged circumferentially around the air bearing rotor. The air bearing stator is provided with a positive pressure assembly and a negative pressure assembly. The positive pressure assembly includes at least one positive pressure inlet, which provides positive pressure gas. The positive pressure gas generates a gas film on the upper end face, lower end face, and inner surface of the air bearing stator located circumferentially around the air bearing rotor. The gas film on the upper and lower end faces of the air bearing stator is annular, while the gas film generated on the inner surface is cylindrical. The negative pressure assembly includes at least one negative pressure inlet, which is used to provide negative pressure gas. The negative pressure gas passes through the air bearing stator and communicates with the first through hole.

[0024] In this embodiment, by placing the air bearing stator within the annular groove surrounding the air bearing rotor and the transfer plate, an air film can be generated on the upper, lower, and inner surfaces of the air bearing stator. This arrangement serves several purposes: firstly, it avoids friction with the air bearing rotor, improving the rotor's rotational accuracy; secondly, because an air film is generated on the upper and lower surfaces of the air bearing stator, the supporting force of the air film increases or decreases accordingly with increasing or decreasing air pressure, thus maintaining the air film thickness and preventing changes in the transfer plate's equilibrium position; and thirdly, it can adapt to various loads. As the load increases, the air film thickness on the upper surface of the air bearing stator increases, while the thickness on the lower surface decreases, achieving a balanced position. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the structure of the precision air-bearing turntable in an embodiment of the present invention;

[0026] Figure 2 This is a schematic diagram of the internal structure of the precision air-bearing turntable in an embodiment of the present invention;

[0027] Figure 3 This is a schematic diagram of the positive pressure component in an embodiment of the present invention;

[0028] Figure 4 This is a schematic diagram of the negative pressure component in an embodiment of the present invention;

[0029] Figure 5 This is a schematic diagram of the external fixed interface in an embodiment of the present invention;

[0030] Figure 6 This is a schematic diagram of the structure of the air-bearing stator in an embodiment of the present invention;

[0031] Figure 7 This is a schematic diagram of the structure of the first type of air-bearing stator and air-bearing rotor in an embodiment of the present invention;

[0032] Figure 8 This is a schematic diagram of the structure of the first type of air-bearing stator and air-bearing rotor in an embodiment of the present invention.

[0033] In the picture:

[0034] 100. Workpiece;

[0035] 1. Mounting base; 11. Positive pressure inlet; 12. Negative pressure inlet; 13. Positive pressure inlet channel; 14. Negative pressure inlet channel; 15. External fixing interface;

[0036] 2. Drive assembly; 21. Motor stator; 22. Motor rotor;

[0037] 3. Air bearing rotor; 31. Transfer plate; 311. First through hole; 312. Third atmospheric annular groove; 32. Connecting plate; 321. Second through hole; 322. Fourth through hole; 323. Horizontal through hole; 324. Connection fixing hole; 325. Leveling interface; 326. Flexible connection interface; 33. Bearing plate; 331. Third through hole;

[0038] 4. Air bearing stator; 41. First positive pressure channel; 42. Second positive pressure channel; 43. Third positive pressure channel; 44. First negative pressure channel; 45. Negative pressure annular groove; 46. First atmospheric annular groove; 461. First connecting hole; 47. Fourth atmospheric annular groove; 48. Fourth connecting hole A; 49. Fourth connecting hole B;

[0039] 51. Partial pressure positive pressure channel; 52. Second atmospheric annular groove;

[0040] 61. Fixing component; 62. Water-cooled box body; 63. Thermal insulation component; 64. Grating; 65. Bearing component; 66. Fixed outer shell; 67. Reading head. Detailed Implementation

[0041] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0042] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. The terms "first position" and "second position" refer to two different positions. Furthermore, "above," "on top of," and "over" the first feature in relation to the second feature includes the first feature directly above and diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "under," and "below" the first feature in relation to the second feature includes the first feature directly below and diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0043] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0044] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0045] Turntable structures typically consist of a base with a coaxial inner and outer ring of a mechanical bearing. The outer ring provides support, while one end of the inner ring connects to the drive assembly, and the other end connects to the load-bearing platform. However, this structure limits the platform's end face runout and radial runout to the bearing, preventing the achievement of higher precision. To address this issue, existing patent literature (CN102011918) discloses a high-precision direct-drive air-bearing turntable. In this case, the air-bearing assembly is a separate unit, with only its vertical end face and rotational surface being air-bearing surfaces. The stator balance position of the air-bearing bearing changes with air pressure. Specifically, when air pressure increases, the turntable height rises; conversely, when air pressure decreases, the turntable height decreases. This instability in turntable height can negatively impact load-bearing performance.

[0046] like Figure 1-6As shown, this embodiment provides a precision air-bearing turntable for high-precision wafer inspection in the semiconductor industry. The precision air-bearing turntable includes a mounting base 1, a drive assembly 2, an air-bearing rotor 3, and an air-bearing stator 4. The drive assembly 2 is screwed to the mounting base 1, and the air-bearing rotor 3 is connected to the output end of the drive assembly 2. An adapter plate 31 is provided at the end of the air-bearing rotor 3, and the adapter plate 31 and the air-bearing rotor 3 form an annular groove. The adapter plate 31 has a first through hole 311. The air-bearing stator 4 is screwed to the mounting base 1, and a portion of the lower end face of the air-bearing stator 4 is parallel to the lower side of the annular groove, and a portion of the upper end face of the air-bearing stator 4 is parallel to the upper side of the annular groove. The inner surface is arranged circumferentially around the air bearing rotor 3. The air bearing stator 4 is provided with a positive pressure component and a negative pressure component. The positive pressure component includes at least one positive pressure inlet 11, which is used to provide positive pressure gas. The positive pressure gas generates a gas film on the upper end face, lower end face, and inner surface of the air bearing stator 4 located circumferentially around the air bearing rotor 3. The gas film on the upper end face and lower end face of the air bearing stator 4 is annular, and the gas film generated on the inner surface is cylindrical. The thickness of the gas film is between 10 micrometers and 15 micrometers. The negative pressure component includes at least one negative pressure inlet 12, which is used to provide negative pressure gas. The negative pressure gas communicates with the first through hole 311 after passing through the air bearing stator 4. The gas film on the upper and lower end faces of the air bearing stator 4 is used to ensure the tilting stiffness of the air bearing rotor 3, and the gas film generated on the inner surface of the air bearing stator 4 is used to ensure the horizontal stiffness of the air bearing rotor 3.

[0047] In this embodiment, by placing the air bearing stator 4 within the annular groove surrounding the air bearing rotor 3 and the transfer plate 31, air films can be generated on the upper, lower, and inner surfaces of the air bearing stator 4. This avoids friction with the air bearing rotor 3, greatly improving the integration of the precision air-bearing turntable, enhancing the rotational accuracy of the air bearing rotor 3, and providing high dynamic stability. Secondly, since air films can be generated on the upper and lower surfaces of the air bearing stator 4, the supporting force of the air films on the upper and lower surfaces of the air bearing stator 4 increases or decreases accordingly when the air pressure increases or decreases. Therefore, the thickness of the air film does not change, and the equilibrium position of the transfer plate 31 does not change with the air pressure. Thirdly, it can also adapt to various loads. When the load increases, the thickness of the air film on the upper surface of the air bearing stator 4 increases, and the thickness of the air film on the lower surface of the air bearing stator 4 decreases, thereby achieving a balanced position.

[0048] Optionally, in this embodiment, the overall height of the precision air-bearing turntable needs to be less than 100mm, the maximum outer diameter less than 300mm, and the first-order mode higher than 500Hz. With these settings, the precision air-bearing turntable can be applied to various working environments, and its small size facilitates transportation and installation.

[0049] In this embodiment, preferably, there are two negative pressure inlets 12, which are located on the side of the mounting base 1. The arrangement of the two negative pressure inlets 12 makes the adsorption force on the wafer more balanced.

[0050] Preferably, the positive pressure assembly further includes a pressure-dividing positive pressure channel 51, a first positive pressure channel 41, a second positive pressure channel 42, and a third positive pressure channel 43. The positive pressure inlet 11 is connected to the pressure-dividing positive pressure channel 51. The first positive pressure channel 41 is connected between the pressure-dividing positive pressure channel 51 and the throttling orifice on the upper end face of the air bearing stator 4. The second positive pressure channel 42 is connected between the pressure-dividing positive pressure channel 51 and the throttling orifice on the lower end face of the air bearing stator 4. The third positive pressure channel 43 is connected between the pressure-dividing positive pressure channel 51 and the throttling orifice on the inner surface of the air bearing stator 4. Specifically, the first positive pressure channel 41, the second positive pressure channel 42, and the third positive pressure channel 43 are all located inside the air bearing stator 4. This arrangement enables the generation of an air film on the upper end face, lower end face, and inner surface of the air bearing stator 4, ensuring that there is an air film on each contact surface between the air bearing stator 4 and the air bearing rotor 3. Furthermore, the throttling holes on the upper end face, lower end face, and inner surface of the air bearing stator 4 are all arranged in a ring around the axial direction of the air bearing stator 4.

[0051] In this embodiment, combined with Figure 7 As shown, optionally, the inner surface of the air bearing stator 4 is cylindrical, and the airflow flows in the annular space between the air bearing stator 4 and the floating shaft 3.

[0052] When the precision air-bearing turntable is fixed as a load on a movable platform, to prevent the air-bearing rotor 3 from contacting the air-bearing stator 4 during its movement along a direction perpendicular to the centerline of the air-bearing stator 4, thus avoiding wear on the air-bearing rotor 3 and / or the air-bearing stator 4, this embodiment combines... Figure 8 As shown, furthermore, the inner surface of the air bearing stator 4 is provided with an annular groove. The cross-section of the annular groove is V-shaped, and the outlet end of the third positive pressure channel 43 is located at the bottom of the annular groove. The depth of the annular groove is 3 micrometers to 10 micrometers, preferably 5 micrometers. This structure allows the airflow to achieve extremely high load-bearing stiffness in a limited space (the thickness of the annular groove between the air bearing stator 4 and the floating shaft 3 is 10 micrometers, and the depth of the annular groove is 5 micrometers, so the air film thickness at the annular groove is 15 micrometers, and the stiffness can reach 35 N / um), thereby allowing the precision air-bearing turntable to be moved as a load in a direction perpendicular to the centerline of the air bearing stator 4.

[0053] Optionally, a positive pressure inlet 11 is provided on the mounting base 1, and the mounting base 1 is also provided with a positive pressure inlet channel 13, which connects the positive pressure inlet 11 and the pressure-dividing positive pressure channel 51. Further, the positive pressure inlet channel 13 is connected to a pressure regulating valve, which is used to regulate the air pressure entering the pressure-dividing positive pressure channel 51. Optionally, the pressure-dividing positive pressure channel 51 is located between the air bearing stator 4 and the mounting base 1. Specifically, the inner diameter of the mounting base 1 where the air bearing stator 4 is mounted is larger than the outer diameter of the air bearing stator 4, and sealing rings are provided at the upper and lower ends of the gap between the mounting base 1 and the air bearing stator 4. The sealing rings, the air bearing stator 4, and the mounting base 1 enclose the pressure-dividing positive pressure channel 51.

[0054] Preferably, the negative pressure assembly further includes a negative pressure inlet channel 14, a first negative pressure channel 44, and a negative pressure annular groove 45. The negative pressure inlet channel 14 and the negative pressure inlet 12 are connected to the first negative pressure channel 44. The negative pressure annular groove 45 is located on the upper end face of the air bearing stator 4. The first negative pressure channel 44 connects the negative pressure inlet channel 14 and the negative pressure annular groove 45, and the negative pressure annular groove 45 is connected to the first through hole 311. Specifically, the negative pressure inlet channel 14 is located on the mounting base 1, the first negative pressure channel 44 is located on the air bearing stator 4, and the negative pressure annular groove 45 is located on the upper end face of the air bearing stator 4. This structure enables the transmission of negative pressure and allows for relative rotation between the adapter plate 31 and the air bearing stator 4.

[0055] Optionally, the adapter plate 31 is provided with a connecting plate 32, which has a second through hole 321 that communicates with the first through hole 311. Specifically, the connecting plate 32 is screwed onto the adapter plate 31, wherein the connecting plate 32 has a connecting fixing hole 324, and the adapter plate 31 has a screw hole, through which a locking bolt passes and is screwed. Further, the connecting plate 32 is provided with a carrier plate 33, which has a third through hole 331 that communicates with the second through hole 321. The carrier plate 33 is used to carry the workpiece 100, and the third through hole 331 is used to adsorb the workpiece 100. In this embodiment, the workpiece 100 can be a wafer; however, in other embodiments, the workpiece 100 can be other products, and is not limited thereto.

[0056] Furthermore, to accommodate the position of the third through hole 331, the connecting plate 32 is provided with a fourth through hole 322. The fourth through hole 322 is arranged parallel to the second through hole 321, and the fourth through hole 322 is located on the side of the second through hole 321 near the axis of the air bearing rotor 3. The second through hole 321 and the fourth through hole 322 are connected through a horizontal through hole 323, and the fourth through hole 322 is connected to the third through hole 331.

[0057] In this embodiment, optionally, the air bearing rotor 3 is provided with an internal channel that runs through the upper and lower end faces of the air bearing rotor 3. That is, the air bearing rotor 3 has a hollow structure. This design makes the air bearing rotor 3 lighter and more integrated. In addition, the hollow structure makes the air bearing rotor 3 more stable during rotation, thereby effectively improving the accuracy of detection.

[0058] In this embodiment, optionally, the connecting plate 32 and the bearing plate 33 are bolted together. Preferably, the bearing plate 33 is made of silicon carbide. Furthermore, to improve the stability of the bolted connection between the connecting plate 32 and the bearing plate 33, each of the connecting plate 32 and the bearing plate 33 has three interfaces. Since the heat generated by the driving component 2 may cause the three interfaces of the connecting plate 32 to become non-coplanar, potentially leading to brittle deformation of the material. To avoid this problem, in this embodiment, preferably, a flexible connecting interface 326 is designed on the connecting plate 32, and the connecting plate 32 is bolted together with the bearing plate 33 through the flexible connecting interface 326. This design solves the vertical decoupling problem of the three-point connection. It should be noted that the flexible connecting interface 326 is well known to those skilled in the art; therefore, its specific structure and working principle will not be described in detail here.

[0059] To ensure effective transmission of negative pressure gas, in this embodiment, a first O-ring is provided between the connecting plate 32 and the bearing plate 33, and a second O-ring is provided between the adapter plate 31 and the connecting plate 32. The first O-ring is located on the connecting plate 32 and surrounds the outer periphery of the fourth through hole 322, and the second O-ring is located on the adapter plate 31 and surrounds the outer periphery of the first through hole 311.

[0060] Preferably, the precision air-bearing turntable further includes an isolation component, which is used to separate the positive pressure gas on the upper end face of the air-bearing stator 4 from the negative pressure gas passing through the air-bearing stator 4, to separate the positive pressure gas on the upper end face and inner surface of the air-bearing stator 4, and to separate the positive pressure gas on the lower end face and inner surface of the air-bearing stator 4. With the above configuration, the gas films on the upper end face, lower end face, and inner surface of the air-bearing stator 4 can be isolated from each other, and the positive pressure gas and negative pressure gas on the upper end face of the air-bearing stator 4 can be isolated, preventing gas crosstalk, stabilizing the airflow, and improving the crosstalk resistance of the air-bearing rotor 3.

[0061] Optionally, the first negative pressure channel 44 penetrates the upper and lower end faces of the air bearing stator 4; the isolation assembly includes a first atmospheric annular groove 46 located on the upper end face of the air bearing stator 4, a second atmospheric annular groove 52 located between the mounting base 1 and the air bearing rotor 3, a third atmospheric annular groove 312 located on the lower end face of the adapter plate 31, and a fourth atmospheric annular groove 47 located at the junction of the lower end face of the air bearing stator 4 and the inner surface of the air bearing stator 4. The first atmospheric annular groove 46 is located between the throttling orifice and the negative pressure annular groove 45 on the upper end face of the air bearing stator 4; the second atmospheric annular groove 52 is located between the throttling orifice and the inlet of the first negative pressure channel 44 on the lower end face of the air bearing stator 4; the third atmospheric annular groove 312 is located at the junction connecting the upper end face of the air bearing stator 4 and the inner surface of the air bearing stator 4. The first atmospheric annular groove 46, the second atmospheric annular groove 52, the third atmospheric annular groove 312, and the fourth atmospheric annular groove 47 are all in communication with the external environment. In this embodiment, the above structure enables isolation between the air films on the air bearing stator 4, as well as isolation between positive and negative air pressures. The second atmospheric annular groove 52 is directly connected to the external environment; the fourth atmospheric annular groove 47 is connected to the external environment through fourth connecting holes A48 and B49. Fourth connecting hole B49 is a horizontal hole inside the air bearing stator 4, connecting the internal channel and the second atmospheric annular groove 52. Fourth connecting hole A48 is an inclined hole inside the air bearing turntable, connecting fourth connecting hole B49 and the fourth atmospheric annular groove 47. The first atmospheric annular groove 46 is connected to the external environment through a first connecting hole 461 located in the air bearing stator 4. Specifically, the first connecting hole 461 connects the first atmospheric annular groove 46 and the second atmospheric annular groove 52, and is parallel to the first negative pressure channel 44. The third atmospheric annular groove 312 is connected to the external environment through a third connecting hole located in the adapter plate 31, which is not shown in the figure.

[0062] In addition, the air bearing stator 4 is an integral structure and can be compatible with three types of gases, with high integration, which makes the overall rigidity of the air bearing rotor 3 in the undulating state high.

[0063] Preferably, the drive assembly 2 may include a motor, wherein the motor includes a motor rotor 22 and a motor stator 21, the motor rotor 22 and the motor stator 21 having a through-hole, the motor stator 21 being fixed to the mounting base 1, and the motor rotor 22 being sleeved on the air bearing rotor 3. This arrangement does not occupy the internal cavity structure of the air bearing rotor 3, making the rotation of the air bearing rotor 3 more stable.

[0064] Furthermore, the precision air-bearing turntable also includes a fixing member 61, which is located on the air-bearing rotor 3. The air-bearing rotor 3 is provided with a support platform, one end of the motor rotor 22 abuts against the support platform, and the other end abuts against the fixing member 61. The fixing member 61 improves the firmness of the connection between the motor rotor 22 and the air-bearing rotor 3.

[0065] The drive assembly 2 generates heat during operation. In order to dissipate the heat, the precision air-bearing turntable in this embodiment also includes a heat dissipation assembly for cooling the drive assembly 2. Specifically, the heat dissipation assembly includes a water-cooling assembly, which includes a water-cooling housing 62. The water-cooling housing 62 is disposed on the mounting base 1 and surrounds the outer periphery of the motor stator 21.

[0066] To reduce the impact of heat generation from the drive assembly 2 on the measurement system and the stability of the air bearing, a heat insulation component 63 is provided between the motor stator 21 and the mounting base 1. The heat insulation component 63 is made of POM material (polyoxymethylene, a thermoplastic crystalline polymer). Specifically, the heat insulation component 63 is located on the mounting base 1, and the heat insulation component 63, the water-cooled housing 62, and the heat insulation component 63 together form a U-shaped groove with its opening facing the air bearing rotor 3. The motor stator 21 is located in the U-shaped groove, and the outer peripheral surface of the motor stator 21 abuts against the water-cooled housing 62.

[0067] To improve the control accuracy of the precision air-bearing rotary table, in this embodiment, optionally, the precision air-bearing rotary table further includes a grating 64 and a support member 65. The support member 65 is disposed on the air-bearing rotor 3. The grating 64 has a through-hole and is sleeved on the air-bearing rotor 3, with one end abutting against the fixing member 61 and the other end abutting against the support member 65. Optionally, the grating 64 and the support member 65 are bonded together. To reduce the impact of the heat generated by the drive assembly 2 on the measurement accuracy of the grating 64, the support member 65 is made of 4J36. 4J36 is a special low-expansion iron-nickel alloy with an ultra-low coefficient of thermal expansion.

[0068] Optionally, the water-cooled housing 62 is connected to an inlet pipe and an outlet pipe, the fixed housing 66 is fixed to the outlet pipe, and the reading head 67 is screwed to the fixed housing 66. The reading head 67 is used to read the grating 64. Preferably, the fixed housing 66 is provided with a height adjustment mechanism, and the reading head 67 is located at the output end of the height adjustment mechanism.

[0069] The adapter plate 31 is the internal interface of the precision floating turntable. The connecting plate 32 is connected to the adapter plate 31 by bolts. The connecting plate 32 can be adjusted relative to the adapter plate 31 in the Rx / Ry direction through the leveling interface 325, which ensures the dimensional error of the upper surface of the connecting plate 32 relative to the mounting base 1.

[0070] Optionally, the mounting base 1 is provided with an external fixing interface 15, which is a threaded hole for screwing the mounting base 1 to an external platform. Furthermore, the mounting base 1 is also provided with an adjustment mechanism for leveling the external fixing interface 15. This configuration allows the precision air-bearing turntable to be leveled both externally and internally, which is beneficial for dimensional chain control during assembly.

[0071] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A precision air-bearing turntable, characterized in that, include: Mounting base (1); The drive component (2) is located on the mounting base (1). An air bearing rotor (3) is connected to the output end of the drive assembly (2); The adapter plate (31) is located at the end of the air bearing rotor (3). The adapter plate (31) and the air bearing rotor (3) are arranged to form an annular groove. The adapter plate (31) is provided with a first through hole (311). An air bearing stator (4) is provided on the mounting base (1), and the lower end face of the air bearing stator (4) is parallel to the lower side of the annular groove. A portion of the upper end face of the air bearing stator (4) is parallel to the upper side of the annular groove. The inner surface of the air bearing stator (4) is arranged around the circumference of the air bearing rotor (3). A positive pressure assembly, the positive pressure assembly including at least one positive pressure inlet (11) for providing positive pressure gas, the positive pressure gas generating a gas film on the upper end face, lower end face and inner surface of the air bearing stator (4) and located in the circumferential direction of the air bearing rotor (3); The positive pressure assembly further includes a pressure-dividing positive pressure channel (51), a first positive pressure channel (41), a second positive pressure channel (42), and a third positive pressure channel (43). The positive pressure inlet (11) is connected to the pressure-dividing positive pressure channel (51). The first positive pressure channel (41) is connected between the pressure-dividing positive pressure channel (51) and the throttling hole on the upper end face of the air bearing stator (4). The second positive pressure channel (42) is connected between the pressure-dividing positive pressure channel (51) and the throttling hole on the lower end face of the air bearing stator (4). The third positive pressure channel (43) is connected between the pressure-dividing positive pressure channel (51) and the throttling hole on the inner surface of the air bearing stator (4). The positive pressure gas generates an air film on the upper surface of the air bearing stator (4) through the first positive pressure channel (41), generates an air film on the lower surface of the air bearing stator (4) through the second positive pressure channel (42), and generates an air film on the inner surface of the air bearing stator (4) through the third positive pressure channel (43). The precision air-bearing turntable also includes a negative pressure component, which includes at least one negative pressure inlet (12). The negative pressure inlet (12) is used to provide negative pressure gas, which passes through the air-bearing stator (4) and communicates with the first through hole (311). The precision air-bearing turntable also includes an isolation component, which is used to separate the positive pressure gas on the upper end face of the air-bearing stator (4) from the negative pressure gas passing through the air-bearing stator (4), to separate the positive pressure gas on the upper end face and inner surface of the air-bearing stator (4), and to separate the positive pressure gas on the lower end face and inner surface of the air-bearing stator (4). The isolation component is in communication with the external environment.

2. The precision air-bearing turntable according to claim 1, characterized in that, The negative pressure assembly further includes a negative pressure inlet channel (14), a first negative pressure channel (44), and a negative pressure annular groove (45); the negative pressure inlet channel (14) and the negative pressure inlet (12) are connected to the first negative pressure channel (44), the negative pressure annular groove (45) is located on the upper end face of the air bearing stator (4), the first negative pressure channel (44) is connected between the negative pressure inlet channel (14) and the negative pressure annular groove (45), and the negative pressure annular groove (45) is connected to the first through hole (311).

3. The precision air-bearing turntable according to claim 2, characterized in that, The first negative pressure channel (44) penetrates the upper and lower end faces of the air bearing stator (4); the isolation assembly includes a first atmospheric annular groove (46) on the upper end face of the air bearing stator (4), a second atmospheric annular groove (52) between the mounting base (1) and the air bearing rotor (3), a third atmospheric annular groove (312) on the lower end face of the adapter plate (31) and a fourth atmospheric annular groove (47) at the junction of the lower end face of the air bearing stator (4) and the inner surface of the air bearing stator (4), wherein the first atmospheric annular groove (46) is located on the air bearing The throttling hole on the upper end face of the bearing stator (4) and the negative pressure annular groove (45) are located between the throttling hole on the lower end face of the air bearing stator (4) and the inlet of the first negative pressure channel (44); the third atmospheric annular groove (312) is located at the junction of the upper end face of the air bearing stator (4) and the inner surface of the air bearing stator (4); the first atmospheric annular groove (46), the second atmospheric annular groove (52), the third atmospheric annular groove (312) and the fourth atmospheric annular groove (47) are all connected to the external environment.

4. The precision air-bearing turntable according to claim 1, characterized in that, The drive assembly (2) includes a motor rotor (22) and a motor stator (21). The motor rotor (22) and the motor stator (21) have a through cavity. The motor stator (21) is fixed to the mounting base (1). The motor rotor (22) is sleeved on the air bearing rotor (3).

5. The precision air-bearing turntable according to claim 4, characterized in that, The precision air-bearing turntable also includes a fixing member (61), which is located on the air-bearing rotor (3). The air-bearing rotor (3) is provided with a support platform. One end of the motor rotor (22) abuts against the support platform, and the other end abuts against the fixing member (61).

6. The precision air-bearing turntable according to any one of claims 1-5, characterized in that, The precision air-bearing turntable also includes a grating (64) and a support member (65). The support member (65) is disposed on the air-bearing rotor (3). The grating (64) has a through cavity. The grating (64) is sleeved on the air-bearing rotor (3) and fixed to the support member (65).

7. The precision air-bearing turntable according to any one of claims 1-5, characterized in that, The precision air-bearing turntable also includes a heat dissipation component, which is used to dissipate heat for the drive component (2).

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