External driving mechanism for ultrahigh vacuum

Abstract

The invention discloses an external driving mechanism for ultrahigh vacuum. The external driving mechanism comprises a vacuum chamber assembly and a driving assembly connected outside the vacuum chamber assembly through a connecting assembly. The driving assembly can achieve large-stroke movement of a driven part and resetting of submicron dimension precision. The output end of the driving assembly is connected with a driven piece, and the driven piece can stretch into the vacuum chamber assembly. According to the ultrahigh vacuum driving device, the driving mechanism is designed outside the ultrahigh vacuum, the pollution of the driving mechanism to the ultrahigh vacuum can be avoided through corrugated pipe connection and knife edge sealing, flexible driving of the driven part can be achieved, and meanwhile, the driving assembly is directly installed on the vacuum chamber assembly, so that errors caused by independent supporting of the driving part are eliminated. Through the arrangement of the bolt adjusting assembly, the driving assembly can drive the driven part to move or rotate relative to the vacuum chamber assembly, and therefore the actual direction requirement of the driven part is met.

Description

Technical Field

[0001] The present invention relates to the technical field of ultra-high vacuum, precision displacement and real-time monitoring of key features of optical elements in a vacuum chamber, and more specifically to an external drive mechanism for ultra-high vacuum with a large stroke. Background Art

[0002] In synchrotrons, free electron lasers, and various beamline devices, it is often necessary to precisely position a probe, sample, pinhole, optical mirror, or slit in five or six dimensions at a certain position in an ultra-high vacuum. During the operation of the device, the positioned object must be withdrawn from the working position with a large stroke. When necessary, it must be precisely reset to the working position. This process is repeated continuously due to work needs. For example, the POP IN probe in the oscillator of the free electron laser device, see Figure 1 The probe is a triangular electron beam trajectory position calibration device with a small hole for calibrating the electron trajectory and a yttrium aluminum garnet crystal target (YAG Crystal) for displaying the electron position. In order to accurately calibrate the electron beam trajectory, the center line of the probe small hole must be installed and adjusted to be concentric with the theoretical laser optical axis of the free electron laser oscillator, and its linear position error is The angle error is less than 5mrad; the probe drive mechanism must have a five-dimensional adjustment function during the installation process (position adjustment along the optical axis is not required); after the electron trajectory centerline calibration is completed, the probe moves 60mm to withdraw from the oscillator optical path. When the electron trajectory needs to be recalibrated during subsequent operation, the probe must accurately return to the theoretical calibration position. Therefore, the drive mechanism must be able to adjust the orientation in five dimensions during installation, and must have ultra-high repeatability requirements after a large stroke movement and return; at the same time, the internal devices are in an ultra-high vacuum chamber, and the position parameters of key features are difficult to measure directly. It is necessary to set multiple targets outside the vacuum chamber that are fixedly associated with the key features of the devices in the vacuum chamber and can be measured. This drive mechanism can accurately implement the precise installation positioning, driving and repeated positioning functions required by the probe.

[0003] The patent document with the patent publication number CN 209216588 U discloses a large-stroke precision piezoelectric displacement stage for ultra-high vacuum, including a displacement stage base and a movable table that is displaced relative to the displacement stage base. Two groups of cross-ball guide rail assemblies are arranged between the displacement stage base and the movable table, and each group of cross-ball guide rail assemblies is provided with two mutually coupled cross-ball guide rails, one of the cross-ball guide rails of each group of cross-ball guide rail assemblies is fixedly connected to the displacement stage base, and the other cross-ball guide rail of each group of cross-ball guide rail assemblies is fixedly connected to the movable table. The large-stroke precision piezoelectric displacement stage for ultra-high vacuum disclosed in this scheme is suitable for ultra-high vacuum and ultra-low temperature environments. While ensuring movement in the stroke direction, it avoids shaking in other directions, thereby ensuring absolute motion accuracy at the nanometer level, but it is not suitable for the movement of original parts such as probes and the positioning of key elements such as the axis position requirements of the probe center hole. Summary of the invention

[0004] The technical problem to be solved by the present invention is:

[0005] 1. How to avoid the contamination of ultra-high vacuum by the drive mechanism;

[0006] 2. Ability to adjust the actual position of the driven parts in 5 dimensions and meet the requirements of precise positioning of key elements;

[0007] 3. It can make the driven part withdraw from the working position with a large stroke, and return to the original working position with high precision;

[0008] 4. Accurately confirm the exact position of the key features of the probe in the vacuum chamber by measuring the position of the external target at any time;

[0009] 5. The driving mechanism is compact and can be directly installed on the vacuum chamber.

[0010] The present invention solves the above technical problems through the following technical means: an external driving mechanism for ultra-high vacuum, comprising a vacuum chamber assembly, a target ball, a fixed base plate fixed on the flange of the vacuum chamber assembly, and a driving assembly connected to the outside of the vacuum chamber assembly through an adjustment assembly, the output end of the driving assembly is connected to a driven part, the driven part can extend into the vacuum chamber assembly, the driving assembly can be coupled with the vacuum chamber assembly through a welded bellows, avoiding contamination of the ultra-high vacuum by the driving mechanism, and flexibly realizing long-range driving of the driven part along the axial direction of the bellows and precise and flexible driving of the five-dimensional installation adjustment. ; The adjustment connection assembly includes a vertical adjustment screw group and a lateral horizontal adjustment group; the vertical adjustment screw group can drive the assembly to move in the Z direction and rotate around the X axis; the lateral horizontal adjustment group can drive the drive assembly to move in the X direction relative to the vacuum chamber assembly and rotate around the Y axis and Z axis; the drive assembly is used to withdraw the driven part from the working position or return to the working position; the target ball is fixed on the drive assembly and is located outside the vacuum chamber, and the orientation of the key features of the probe connected to the vacuum chamber assembly can be obtained by measuring the center position of the target ball; the drive mechanism is installed on the knife-edge flange of the vacuum chamber assembly.

[0011] As a preferred technical solution, the adjustment assembly includes a vertical adjustment screw group and a lateral horizontal adjustment group. The vertical adjustment screw group includes two fine-thread adjustment screws arranged at the bottom of the fixed base plate and an elastic plunger screw at the top. The elastic plunger screw is used to drive the adjustment base plate on the driving assembly to be in close contact with the two fine-thread adjustment screws at the bottom. The vertical adjustment screw group is used to drive the driving assembly to translate in the Z direction and rotate around the X axis.

[0012] As an optimal technical solution, the lateral horizontal adjustment group includes three bolt adjustment components, and the bolt adjustment components include a concave conical gasket, an adjusting threaded sleeve, a locking nut, a rectangular coil spring, and a clamping screw. The concave conical gasket can contact the floating plane of the fixed base plate; the end spherical surface of the adjusting threaded sleeve presses against the conical surface of the concave conical gasket; the adjusting threaded sleeve is screwed into the screw hole of the adjusting base plate of the driving component; the adjusting threaded sleeve is screwed on the locking nut; the clamping screw passes through the rectangular coil spring, and the adjusting threaded sleeve and the concave conical gasket are screwed into the screw hole of the fixed base plate; the clamping amount of the rectangular coil spring here is adjusted during installation, and its elastic force ensures that the driving component does not overturn due to gravity, and allows the vertical adjustment screw group to verify the installation adjustment of the driving component; the three bolt adjustment components are arranged in a triangle, and adjusting the corresponding bolt adjustment components can realize the two-dimensional rotation and one-dimensional translation adjustment of the driving component connected to the adjusting base plate relative to the fixed base plate component.

[0013] By adjusting the screw-in amount of the clamping screw, the clamping force can be adjusted through the rectangular coil spring to ensure that the drive assembly can still be firmly fixed on the vacuum chamber under the action of gravity. At the same time, due to the existence of elasticity, the vertical adjustment screw group can be allowed to adjust the Z direction or rotation around the X axis of the drive assembly.

[0014] As a preferred technical solution, the output end of the driving assembly is connected to the driven part through a transmission shaft, and the fixed base plate is bolted to press the knife-edge flange onto the sealing copper gasket of the vacuum chamber assembly to achieve vacuum sealing; the knife-edge flange is seal-welded to one end of the bellows, and the other end of the bellows is seal-welded to the end of the transmission shaft; the bellows serves as a flexible coupling connector that not only ensures the vacuum sealing of the vacuum chamber but also allows the driven part to be installed and adjusted to the working position, withdrawn from the working position over a long stroke, and reset with flexibility.

[0015] As a preferred technical solution, the driving assembly includes an adjusting base plate, a displacement platform base, a precision displacement platform, a coupling, a stepper motor, a moving plate, a transmission shaft, a knife-edge flange, and a bellows; the displacement platform base is fixedly mounted on the adjusting base plate with screws, the precision displacement platform is mounted on the displacement platform base, the two moving sliders of the precision displacement platform are fixedly connected with a displacement plate, the displacement plate is connected to the driven part through a transmission shaft, the stepper motor is mounted at the end of the precision displacement platform, and the output shaft of the stepper motor is transmission-connected to the screw input shaft of the precision displacement platform through a coupling; when the stepper motor rotates, the driving screw of the precision displacement platform drives the two sliders to perform translational motion, thereby driving the displacement plate, the connecting shaft and the driven part to perform translational motion.

[0016] As a preferred technical solution, the drive mechanism also includes a Renishaw grating scale assembly, a travel switch assembly, and a controller; the controller is electrically or communicatively connected to the precision displacement platform, the absolute grating scale assembly, and the travel switch assembly; the linearity of the movement of this drive mechanism can be met by selecting the accuracy level of the precision drive platform as required; the movement step length of this drive mechanism can be met by selecting the drive screw pitch of the precision drive platform, the stepper motor, and the number of differential drive microsteps of the motor driver as required; the repeatability of the positioning accuracy of this drive mechanism can be determined by selecting the appropriate accuracy level of the precision drive platform and the appropriate accuracy level of the grating scale assembly as required.

[0017] As a preferred technical solution, the absolute grating ruler assembly includes a grating ruler reading head and a grating ruler, wherein the grating ruler reading head is fixedly connected to the displacement platform base, and the grating ruler is fixedly connected to the displacement plate; when the displacement plate drives the grating ruler to move, the grating ruler reading head scans the grating ruler to accurately read the displacement. According to the closed-loop control characteristic, the accuracy of the grating represents the repeatability of the driving mechanism.

[0018] As a preferred technical solution, the travel switch assembly includes a travel switch paddle and a travel switch, the travel switch paddle is fixedly connected to the displacement plate, and the two travel switches are fixedly connected to the displacement platform base; when the displacement plate drives the travel switch paddle to move to trigger one travel switch, the movement in this direction is stopped, and the reverse movement is stopped to trigger another travel switch.

[0019] As a preferred technical solution, the displacement plate can also form a hard stop for the motion of the drive assembly. If the travel switch fails, the displacement plate moves forward until one end face abuts against the adjustment plate, and the feeding motion is hard stopped; the displacement plate withdraws until the other end face of the displacement plate abuts against the rear end step of the displacement platform, and the withdrawal motion is hard stopped. The function of the hard stop is to hard limit the driving stroke in case the travel switch fails, thereby protecting the driven parts and the bellows (vacuum) from damage.

[0020] As a preferred technical solution, the displacement plate is provided with a target ball seat that is compatible with the target ball. The target ball seat has a 90° concave cone. The target ball can be installed on the target ball seat with ultra-high repeatability accuracy at any time. The driven part and the four target balls outside the vacuum have a fixed positional relationship. After calibrating this relationship with an appropriate instrument (such as an articulated arm), the actual position of the driven part in the vacuum can be obtained at any time by measuring the positions of the four target balls outside the vacuum using CAD means.

[0021] As a preferred technical solution, the precision displacement platform uses the THK KR2001B-0035-P0 motion platform, the stepper motor uses the Oriental Motor PKP523N12B model, the grating scale assembly uses the Renishaw ResoluteTM absolute grating scale, and the travel switch assembly uses the Omron D2MQ-1-TR micro travel switch, which are combined into a closed-loop controlled precision drive positioning system to ensure that the position repeatability accuracy of the driven part when it withdraws from the workbench position and returns reaches the micron level.

[0022] The beneficial effects of the present invention are:

[0023] (1) In the present invention, by designing the driving mechanism outside the ultra-high vacuum and coupling it in the middle through a welded bellows, not only can the driving mechanism avoid contamination of the ultra-high vacuum, but also can achieve a large-stroke precision drive of the driven part, ensuring the flexibility of the precision drive. The drive of the driven part here includes five-dimensional installation adjustment drive and long-stroke exit working position and precision return drive.

[0024] (2) In the present invention, by setting the vertical adjustment screw group and the lateral horizontal adjustment group, the five-dimensional installation adjustment of the driven part in the vacuum chamber assembly can be realized, so that the center line of the probe hole is installed to the theoretical position, and then a large stroke displacement and precise resetting can be achieved through the precision displacement platform.

[0025] (3) In the present invention, the entire driving mechanism is directly mounted on the flange of the vacuum chamber to avoid large position errors caused by independent support on the ground.

[0026] (4) In the present invention, a THK KR2001B-0035-P0 motion platform, a stepper PKP523N12B Oriental motor, a Renishaw ResoluteTM absolute grating ruler, and an Omron D2MQ-1-TR micro-travel switch are used to form a closed-loop controlled precision drive positioning system to ensure the linearity of the motion of the driven part, to withdraw from the working position to the accurate specified position, and to ensure ultra-high repeatability when returning.

[0027] (5) In the present invention, the movement data of the displacement platform can be obtained according to the reading of the grating ruler, thereby obtaining the movement of the driven part and realizing real-time reading. The repeatability of the driving mechanism depends on the reading accuracy of the grating ruler, which is in the micron level.

[0028] (6) In the present invention, a combination of micro-travel switches is used to limit the translational motion operation range; the length of the displacement plate is used to rigidly limit the stroke when the travel switch fails to protect the driven part from being damaged due to excessive stroke.

[0029] (7) In the present invention, by providing a plurality of target ball seats and rigidly connecting them to the driven part, the relative position relationship between the four target balls and the driven part such as the probe is calibrated, and the coordinates of the center positions of the four target balls can be measured outside the vacuum at any time to check the orientation of the driven part.

[0030] (8) In the present invention, the driving mechanism can be installed on the blade mounting flange of any vacuum system, and the length of the transmission shaft and the welding bellows and the stroke of the THK precision motion platform can be adjusted to adapt to different driving strokes and positions of the driven parts. The driven part can be an optical mirror holder, a fluorescent target, a target ball or a slit, that is, the two sets of mechanisms are combined into a slit that can be scanned and the slit width can be adjusted. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 A schematic diagram of a probe structure provided as the background technology of the present invention;

[0032] Figure 2 A schematic diagram of a half-section structure provided by an embodiment of the present invention;

[0033] Figure 3 A schematic diagram of an axonometric structure provided for an embodiment of the present invention;

[0034] Figure 4 An axonometric diagram of a drive assembly provided in an embodiment of the present invention;

[0035] Figure 5A schematic diagram of the cross-sectional structure of an adjusting bolt assembly provided in an embodiment of the present invention;

[0036] Figure numbers: 1. Vacuum chamber assembly; 11. Vacuum chamber body; 12. Mounting flange; 13. Sealing copper pad; 2. Fixed base plate; 3. Vertical adjustment screw group; 31. Elastic plunger screw; 32. Fine-thread adjustment screw; 33. Screw locking nut; 4. Horizontal horizontal adjustment group; 41. Concave conical gasket; 42. Adjusting threaded sleeve; 43. Locking nut; 44. Rectangular spiral spring; 45. Compression screw; 5. Drive assembly; 501. Adjustment base plate; 502. Displacement platform base; 503. Precision displacement platform; 504. Coupling; 505. Stepper motor; 506. Displacement plate; 507. Transmission shaft; 508. Knife-edge flange; 509. Welded bellows; 510. Travel switch paddle; 511. Travel switch; 512. Target ball seat; 513. Grating ruler reading head; 514. Grating ruler; 6. Probe; 7. Target ball. DETAILED DESCRIPTION

[0037] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in combination with the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0038] See also Figure 2 , 3 In this embodiment, the length direction of the vacuum component 1 is the Y direction, the height direction is the Z direction, the width direction is the X direction, and the optical axis direction of the laser is the Y direction.

[0039] See also Figure 2 , Figure 3 , an external driving mechanism for ultra-high vacuum with a long stroke, comprising a vacuum chamber assembly 1, a vertical adjustment screw group 3, a lateral horizontal adjustment group 4, a driving assembly 5, a driven part 6, and a target ball 7; the driving assembly 5 is connected to the outside of the vacuum chamber assembly 1 through a connecting assembly, the driving assembly 5 is provided with a target ball 7, the output end of the driving assembly 5 is connected to the driven part 6, the driven part can be extended into the vacuum assembly 1, the driving assembly 5 is mainly used to drive the operation, withdrawal and reset of the probe 6 in the vacuum chamber assembly 1, it should be noted that the probe 6 can also be a required sample, a small hole, a mirror frame, a slit, etc.; the driven part is the probe 6, and the probe 6 is a POP IN probe;

[0040] The vacuum chamber assembly 1 comprises a vacuum chamber body 11, a mounting flange 12, and a sealing copper gasket 13. The mounting flange 12 is fixedly connected to one end of the vacuum chamber body 11 facing the probe 6, and the sealing copper gasket 13 is fixedly connected to one end of the mounting flange 12 facing the fixed base plate 2.

[0041] The connection assembly includes a fixed base plate 2, a vertical adjustment screw assembly 3, a lateral adjustment group 4, an adjustment base plate 501, and a welding bellows 509. The fixed base plate 2 is fixed to the vacuum chamber flange of the vacuum chamber assembly 1. One end of the welding bellows 509 is connected to the knife-edge flange 508, and the other end is connected to the transmission shaft 507. The welding bellows 509 is both a flexible connection between the vacuum chamber assembly 1 and the transmission shaft 507 and a vacuum seal. The lateral adjustment group 4 and the vertical adjustment screw group 3 can adjust the posture of the external drive mechanism as required, so as to install and position the drive assembly 5.

[0042] See also Figure 2 , Figure 3 , Figure 4 The fixed base plate 2 is fixedly mounted on the mounting flange 12 of the vacuum chamber assembly 1 by six groups of bolts, nuts and gaskets. The fixed base plate 2 compresses the knife-edge flange 508 on the driving assembly 5 and the sealing copper gasket 13 on the vacuum chamber assembly 1 to perform ultra-high vacuum sealing. Two fine-thread screw holes are opened at the lower part of the fixed base plate 2 for installing two fine-thread adjustment screws 32 in the vertical screw group 3. A screw hole is opened at the upper part of the fixed base plate 2 for installing the elastic plunger screw 31 in the vertical screw group 3. Three screw holes are opened on the plane of the fixed base plate 2 to match the clamping screws 45 on the lateral horizontal adjustment group 4.

[0043] See also Figure 2 , Figure 3In this embodiment, the vertical adjustment screw group 3 includes two fine-thread adjustment screws 32 at the bottom and an elastic plunger screw 31 at the top. The two fine-thread adjustment screws 32 and the elastic plunger screw 31 are respectively screwed into three corresponding screw holes on the fixed base plate 2. The heads of the two fine-thread adjustment screws 32 are against the lower surface of the adjustment base plate 501 of the driving component 5; the heads of the elastic plunger screws 32 elastically press the displacement platform base 502 on the driving component 5 to keep the adjustment base plate 501 in close contact with the fine-thread adjustment screws 32; the two fine-thread adjustment screws 32 at the bottom are adjusted simultaneously, in the same direction, and in the same amount, so that the adjustment can be made. The linear vertical position (Z coordinate) of the drive assembly 5 is adjusted, the pitch of the fine-thread adjustment screw 32 is 0.5mm, and the linear adjustment step is 0.5mm / 360°, which is equal to 1.4μm / °; when the adjustment amounts of the two fine-thread adjustment screws 32 are different, the rotation of the drive assembly 5 around the X-axis can be adjusted, and the rotation step is 1.4μm / ° / 100mm (the distance between the two fine-thread adjustment screws 32), which is equal to 0.014mrad / °; when the adjustment is in place, the two fine-thread adjustment screws 32 and one elastic plunger screw 31 are locked with a locking nut 33 to maintain the stability of the position;

[0044] See also Figure 2 , Figure 3 , Figure 5 In this embodiment, the lateral level adjustment group 4 includes three groups of identical bolt adjustment components; the bolt adjustment components include a concave conical gasket 41, an adjusting threaded sleeve 42, a locking nut 43, a rectangular coil spring 44, and a clamping screw 45. The concave conical gasket 41 is in plane contact with the fixed base plate 2, the adjusting threaded sleeve 42 is threadedly connected to the adjusting base plate 501, the adjusting threaded sleeve 42 and the locking nut 43 are threadedly matched, the arc bottom surface of the adjusting threaded sleeve 42 is matched with the groove surface inside the concave conical gasket 41, the rectangular coil spring 44 is sleeved between the clamping screw 45 and the adjusting threaded sleeve 42, one end of the clamping screw 45 can pass through the adjusting threaded sleeve 42 and be threadedly connected to the fixed base plate 2, and the other end clamps the rectangular coil spring 44, and tightening the clamping screw 45 can compress the rectangular coil spring 44, the adjusting threaded sleeve 42 and the concave conical gasket 41.

[0045] See also Figure 5, the plane of the concave conical gasket 41 in the bolt adjustment assembly contacts with the fixed base plate 2 and is movable within the plane; the ball head of the adjusting threaded sleeve 42 abuts against the inner conical surface of the concave conical gasket 41, and the ball head and the inner conical surface will maintain stable contact no matter how to adjust; the adjusting threaded sleeve 42 is screwed into the corresponding screw hole of the adjusting base plate 501, and rotating the adjusting threaded sleeve 42 can change the distance between the adjusting base plate 501 and the fixed base plate 2, and the locking nut 43 is used to lock the adjusting threaded sleeve after adjusting it in place and then rotate it; the two ends of the rectangular coil spring 44 are respectively against the adjusting threaded sleeve 42 and the clamping screw 45; the clamping screw 45 passes through the rectangular coil spring 44, the adjusting threaded sleeve 42, and the concave conical gasket 41 and is screwed into the corresponding screw hole of the fixed base plate 2; by adjusting the screw-in depth of the clamping screw 45, the elastic force of the rectangular coil spring 44 can be adjusted, so that the ball head of the adjusting threaded sleeve 42 always keeps in contact with the concave conical gasket 41.

[0046] Due to the elasticity of the rectangular coil spring 44, the adjusting base plate 501 can still move appropriately in the vertical direction under the action of the vertical adjusting screw group 3, and the three sets of bolt adjustment components are arranged in a triangle; when adjusting at the same time, linear adjustment in the X direction can be obtained, the pitch of the adjusting thread sleeve 42 is adjusted to 0.5mm, and the adjustment step is 1.4μm / °; by adjusting the three sets of horizontal adjustment components 4, the rotation adjustment of the driving component 5 around the Y axis and the Z axis can be obtained, and the adjustment step is 0.014mrad / °;

[0047] In this way, we can obtain Z-direction translation and 2-dimensional adjustment around the X-axis from the vertical adjustment screw assembly 3; X-direction translation and 3-dimensional adjustment around the Y-axis and Z-axis can be performed from the lateral horizontal adjustment assembly 4, which together can obtain 5-dimensional installation adjustment.

[0048] The vacuum chamber assembly 1 is a six-way structure, which generally has three mutually interpenetrating pipes, and the axes of the three pipes intersect at a central point, forming a chamber at the intersection, and the driven part can move from the center of the chamber to the pipe; wherein, the shape of the actual vacuum chamber does not affect the use of this mechanism, and it can be any vacuum chamber in actual application; the knife edge of the mounting flange 12 matches the knife edge flange 508 of the driving assembly 5, and the driving structure can be installed and used. At the same time, according to the running stroke requirements of the driving mechanism, a welding bellows 509 of a suitable length and a precision displacement platform 503 of a suitable stroke can be selected to match.

[0049] See also Figure 2 , Figure 3 , Figure 4 The driving assembly 5 includes an adjusting base plate 501, a displacement platform base 502, a precision displacement platform 503, a coupling 504, a stepping motor 505, a displacement plate 506, a transmission shaft 507, a knife-edge flange 508, a welding bellows 509, a travel switch paddle 510, a travel switch 511, a target ball seat 512, a grating scale reading head 513, and a grating scale 514.

[0050] See also Figure 4 The adjusting base plate 501 is the supporting structure of the entire driving assembly 5. The displacement platform base 502 is fixed to the adjusting base plate 501 with two screws. The precision displacement platform 503 is fixed to the displacement platform base 502 with six screws. The precision displacement platform 503 is a commercially available part. The coupling 504 is used to connect the driving shaft of the precision displacement platform 503 and the output shaft of the stepper motor 505. The stepper motor 505 is a commercially available Oriental motor with a model of PKP523N12B, which takes 500 steps per revolution. The displacement plate 506 is fixed to the two sliders of the precision displacement platform 503 with eight screws. The rotation of the stepper motor 505 can drive the displacement plate 506 to move horizontally through the lead screw, nut, and slider on the precision displacement platform. There is a precision guide rail between the slider and the base of the precision displacement platform 503 to ensure the linearity of the movement of the slider and the displacement plate 506. The model of the precision displacement platform 503 is a commercially available THK KR2001B-0035-P0, the pitch of the driving screw is 1mm, the moving step length of the displacement plate 506 is 1mm / 500 steps, which is equal to 2μm / step. When the stepper motor 505 is driven by 1 / 10 microstep, the moving step length of the displacement plate 506 can reach 0.2μm / microstep.

[0051] One end of the transmission shaft 507 is fixed to the displacement plate 506 by two screws and moves with the displacement plate 506; the other end of the transmission shaft 507 passes through the adjustment base plate 501, the knife-edge flange 508, and the welded bellows 509; one end of the welded bellows 509 is sealed and welded to the end of the transmission shaft 507, and the other end is vacuum-sealed and welded to the knife-edge flange 508; the end of the transmission shaft 507 is designed with a suitable mounting platform for mounting the driven part; in this way, even if the knife-edge flange 508 is fixed on the vacuum chamber mounting flange 12, the driven part can still be adjusted to the ideal mounting position through the adjustment base plate 501 through the vertical adjustment screw group 3 and the lateral horizontal adjustment component 4; the probe 6 is driven in the X direction for a long distance by the stepping motor 505, and the stroke of this embodiment is 60 mm.

[0052] See also Figure 3 , Figure 4 The grating scale reading head 513 on the driving component 5 is fixedly mounted on the displacement platform base 502 with two screws; the grating scale 514 is fixedly bonded to the displacement plate 506, so that when the stepper motor 505 drives the displacement plate 506 and the probe 6 to move, the grating scale reading head 513 scans the grating scale 514 to accurately detect the movement of the probe; the grating scale 514 is a commercially available Renishaw ResoluteTM absolute grating scale with a reading step of 0.1μm and a reading accuracy of 1 micron; the probe on the transmission shaft 507 can be accurately reset to an accuracy of 1μm.

[0053] See also Figure 4, two travel switches 511 are installed on the displacement platform base 502 with screws, and the displacement switch paddle 510 is fixedly installed on the displacement plate 506. The two travel switches 511 are respectively used to limit the two extreme positions of the probe movement. When the displacement plate 506 drives the travel switch paddle 510 to trigger one of the travel switch 511 contacts, the travel switch 511 sends a signal to the control system to cut off the power supply of the stepper motor 505. When the reverse movement triggers the other travel switch 511 contact, the power supply of the stepper motor 505 is also cut off; in this way, the entire stroke is limited to the area specified by the two travel switches 511; the travel switch component is a commercially available Omron D2MQ-1-TR micro travel switch, and its stop position accuracy is 2μm.

[0054] See also Figure 4 , the displacement plate 506 also serves as a hard stop in this embodiment; the function of the hard stop is to prevent the probe from feeding or withdrawing too much when the travel switch 511 fails, thereby damaging precision components, such as the probe 6 and the welding bellows 509 in this embodiment; assuming that the travel switch 511 fails, the displacement plate 506 drives the probe 6 to feed and move beyond the position of the travel switch 511 to a certain amount, and the left end of the displacement plate 506 will resist the adjustment base plate 501 and forcibly prevent the probe from continuing to feed; on the contrary, when withdrawing beyond the limit position of the travel switch 511, the end face of the groove at the right end of the displacement plate 506 will resist the rear end step of the precision displacement platform 503 and forcibly prevent the probe from further withdrawing.

[0055] See also Figure 4 , a plurality of target ball seats 512 are provided on the displacement plate 506, and the target ball seats 512 are used to install the target balls 7. In this embodiment, four target balls 7 are taken as an example, which are respectively located at the four corners of the displacement plate 506. In this embodiment, the probe 6, the connecting shaft 507, the displacement plate 506 and the four target ball seats 512 are fixedly connected; no matter how the probe 6 is adjusted and driven, its central position relationship with the target balls installed on the four target ball seats 512 will always remain unchanged. Whenever the central position of the four target balls 7 is measured by a laser tracker, the real-time position of the driven part (probe) can be obtained by CAD means; the target ball 7 is a commercially available laser tracker optical accessory.

[0056] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features thereof may be replaced by equivalents. For example, the driven part may also be an optical lens holder, a fluorescent target, a slit, a target, etc., but is not limited thereto. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. An external drive mechanism for ultra-high vacuum, characterized in that: The invention comprises a vacuum chamber assembly (1), a target ball (7), a fixed base plate (2) fixed on a flange of the vacuum chamber assembly (1), and a driving assembly (5) connected to the outside of the vacuum chamber assembly (1) via an adjusting assembly, wherein the output end of the driving assembly (5) is connected to a driven component, the driven component can extend into the vacuum chamber assembly (1), and the driving assembly (5) can be coupled to the vacuum chamber assembly (1) via a welded bellows (509); the adjusting assembly comprises a vertical adjusting screw group (3) and a horizontal adjusting screw group (4); the vertical adjusting screw The group (3) can drive the component (5) to move in the Z direction and rotate around the X axis; the lateral level adjustment group (4) can drive the drive component (5) to move in the X direction relative to the vacuum chamber component (1) and rotate around the Y axis and the Z axis; the drive component (5) is used to withdraw the driven part from the working position or return to the working position; the target ball (7) is fixed on the drive component (5) and is located outside the vacuum chamber, and the position of the driven part can be obtained by measuring the center position of the target ball (7); the drive component (5) is installed on the mounting flange (12) of the vacuum chamber component (1).

2. The ultra-high vacuum external drive mechanism according to claim 1, characterized in that: The adjustment assembly comprises a vertical adjustment screw group (3) and a lateral adjustment screw group (4); the vertical adjustment screw group (3) comprises two fine-thread adjustment screws (32) arranged at the bottom of the fixed base plate (2), an elastic plunger screw (31) at the top and a screw locking nut (33); the elastic plunger screw (31) is used to drive the adjustment base plate (501) on the driving assembly (5) to be in close contact with the two fine-thread adjustment screws (32) at the bottom; the vertical adjustment screw group (3) is used to drive the driving assembly (5) to translate in the Z direction and rotate around the X axis.

3. The ultra-high vacuum external drive mechanism according to claim 1, characterized in that: The lateral level adjustment group (4) comprises three bolt adjustment components, which include a concave conical gasket (41), an adjusting threaded sleeve (42), a locking nut (43), a rectangular helical spring (44), and a clamping screw (45). The concave conical gasket (41) can contact the floating plane of the fixed base plate (2); the end spherical surface of the adjusting threaded sleeve (42) presses against the concave conical gasket (41); the adjusting threaded sleeve (42) is screwed into the screw hole of the adjusting base plate (501) of the driving component (5); the adjusting threaded sleeve (42) is screwed externally on the locking nut (43); the clamping screw (45) passes through the rectangular helical spring (44), and the adjusting threaded sleeve (42) and the concave conical gasket (41) are screwed into the screw hole of the fixed base plate (2).

4. The ultra-high vacuum external drive mechanism according to claim 1, characterized in that: The output end of the driving assembly (5) is connected to the driven component via a transmission shaft (507), and the fixed base plate (2) is connected by bolts to press the knife-edge flange (508) onto the sealing copper gasket (13) of the vacuum chamber assembly (1).

5. The ultra-high vacuum external drive mechanism according to claim 1, characterized in that: The driving assembly (5) comprises an adjusting base plate (501), a displacement platform base (502), a precision displacement platform (503), a coupling (504), a stepping motor (505), a displacement plate (506), a transmission shaft (507), a knife-edge flange (508), and a welded bellows (509); the displacement platform base (502) is fixedly mounted on the adjusting base plate (501) by screws, the precision displacement platform (503) is mounted on the displacement platform base (502), and two movable The slider is fixedly connected with a displacement plate (506), and the displacement plate (506) is connected to the driven member through a transmission shaft (507). The stepper motor (505) is installed at the end of the precision displacement platform (503), and the output shaft of the stepper motor (505) is transmission-connected to the lead screw input shaft of the precision displacement platform (503) through a coupling (504). The knife-edge flange (508) is seal-welded to one end of a welding bellows (509), and the other end of the welding bellows (509) is seal-welded to the end of the transmission shaft (507).

6. The ultra-high vacuum external drive mechanism according to claim 5, characterized in that: The drive assembly (5) further comprises a Renishaw grating scale assembly, a travel switch assembly, and a controller; the controller is electrically or communicatively connected to the precision displacement platform (503), the absolute grating scale assembly, and the travel switch assembly.

7. The ultra-high vacuum external drive mechanism according to claim 6, characterized in that: The absolute grating ruler assembly comprises a grating ruler reading head (513) and a grating ruler (514), wherein the grating ruler reading head (513) is fixedly connected to the displacement platform base (502), and the grating ruler (514) is fixedly connected to the displacement plate (506).

8. The ultra-high vacuum external drive mechanism according to claim 6, characterized in that: The travel switch assembly comprises a travel switch paddle (510) and a travel switch (511); the travel switch paddle (510) is fixedly connected to the displacement plate (506); and the two travel switches (511) are fixedly connected to the displacement platform base (502).

9. The ultra-high vacuum external drive mechanism according to claim 5, characterized in that: The displacement plate (506) can also form a hard stop for the movement of the drive assembly (5).

10. The ultra-high vacuum external drive mechanism according to claim 5, characterized in that: The displacement plate (506) is provided with a target ball seat (512) adapted to the target ball (7).

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