Ultrahigh vacuum feed-in large-stroke displacement reflector precise switching mechanism

Abstract

The invention belongs to the technical field of synchrotron radiation, and discloses an ultrahigh vacuum feed-in large-stroke displacement reflector precise switching mechanism which is characterized by comprising a driving assembly arranged outside a vacuum, a vacuum motion transmission assembly and an execution assembly located in the vacuum. The driving assembly is connected with the vacuum motion transmission assembly and used for driving the vacuum motion transmission assembly to linearly move in the axial direction. The vacuum motion transmission assembly is connected with the execution assembly in a sealed mode and used for pushing the reflector frame to do linear motion in the axial direction under driving of the driving assembly. An anti-torsion telescopic mechanism is arranged between the driving assembly and the vacuum motion transmission assembly; the anti-torsion telescopic mechanism has the axial telescopic capacity and is used for conducting coordinated movement with the axial displacement of the driving assembly and bearing the torque and gravity generated by the driving assembly. The limitation of a flexible structure on the stroke is broken through, a larger linear switching stroke is achieved on the premise that the overall size is not increased, the transmission efficiency is improved, and the structural design is simplified.

Description

Technical Field

[0001] This invention belongs to the field of synchrotron radiation technology and relates to a precision switching technology for ultra-high vacuum fed large-stroke displacement reflectors. Background Technology

[0002] Fourth-generation synchrotron radiation sources (SRRFs) are characterized by extremely low emissivity, high brightness, and high coherence, placing stringent demands on beamlines. The KB mirror box, the core component at the end of the beamline, directly impacts the beamline's final performance. SRRFs in the low-energy region are capable of producing high-quality soft X-rays. To realize their multimodal experimental potential, the KB mirror box needs to be able to switch between different mirror types in an ultra-high vacuum environment. Currently used vacuum switching schemes are insufficient for ultra-high vacuum requirements, while external vacuum drive schemes are limited by insufficient travel or overly complex structures, requiring compromises through comprehensive optimization. Therefore, developing a multi-mirror switching mechanism suitable for ultra-high vacuum is a key technology in the development of advanced beamline KB mirror boxes, and presents significant challenges.

[0003] Research indicates that the current mechanism enabling large-stroke displacement switching of mirrors within a vacuum is primarily the universal mirror box design from the European company XFEL. This design employs a six-bar parallel mechanism, where five struts are driven by stepper motors, providing active adjustment capabilities. One non-driven strut is used to fix the position in the beam direction and does not contribute to adjustment freedom. The stepper motors drive a lead screw for translation in the X and Y directions, with a stroke of ±50mm and a resolution of 70nm. Some struts integrate piezoelectric ceramic stacks for fine-tuning rotation around the X and Z axes, providing higher resolution and dynamic response. Flexible joints made of stainless steel rope segments are used at both ends of the struts, allowing for minute deflections in multiple directions while maintaining high axial stiffness. By adjusting the lengths of multiple struts, translation and rotation of the mirror in three-dimensional space are achieved. The mirror can be completely moved out of the beam path or precisely aligned to the beam center. The motor moves linearly with the lead screw, with torque and motor weight borne by the flexible mechanism, achieving a total stroke of up to 100mm. The system utilizes a 1mm lead screw, paired with a 72:1 reduction ratio stepper motor, to achieve a 70nm resolution. Piezoelectric ceramics provide sub-nanometer micro-motion, suitable for high-frequency dynamic compensation. The specific structure is as follows: Figure 1 As shown.

[0004] The lead screw drive uses a nut and sliding bearing as the guiding and switching mechanism, and is designed with internal lubrication channels to ensure long-term operation. The motor torque is handled by a specialized flexible structure.

[0005] Based on the closest existing technology mentioned above, its main disadvantages are as follows: (1) The contradiction between stroke and volume: The stepper motor directly drives the lead screw, and the displacement stroke is mainly determined by the length of the lead screw. As the stroke increases, the deformation of the flexible structure used to bear the motor torque increases, and the stress also increases, which can easily lead to structural failure. At the same time, the force required to compress the flexible structure also increases, increasing the burden on the motor. In order to keep it within the yield stress of the material, the size of the flexible structure must be increased, which is not suitable for the compact beamline station.

[0006] (2) The ball screw drive is converted by a sliding bearing. The resulting sliding friction will reduce the efficiency of the ball screw. Although the designed lubrication track will reduce the friction between the screw and the bearing, it will not change the nature of sliding friction and will increase the complexity of the structure. Summary of the Invention

[0007] To address the problems existing in the prior art, the present invention aims to provide a precision switching mechanism for ultra-high vacuum-feed, large-stroke displacement reflectors, suitable for ultra-high vacuum reflector switching in the field of soft X-rays from fourth-generation synchrotron radiation sources. It enables switching between reflectors of different surface shapes within an ultra-high vacuum environment. The drive mechanism is located outside the vacuum and fed in through a bellows. A support rod extends deep into the vacuum to drive the reflector movement, reducing the number of moving parts inside the vacuum, protecting the ultra-high vacuum environment, and solving the problem of large-stroke displacement switching in the synchrotron radiation field. This invention not only overcomes the limitations of flexible structures on stroke, achieving a larger linear switching stroke without increasing the overall size, but also improves transmission efficiency and simplifies structural design.

[0008] The technical solution of this invention is as follows: A precision switching mechanism for a large-stroke displacement mirror fed by an ultra-high vacuum is characterized by comprising a drive component placed outside the vacuum, a vacuum motion transmission component, and an execution component located inside the vacuum. The driving component is connected to the vacuum motion transmission component and is used to drive the vacuum motion transmission component to move linearly along the axial direction; The vacuum motion transmission component is sealed to the execution component and is used to push the reflector frame to move linearly along the axial direction under the drive of the drive component. An anti-torsion telescopic mechanism is provided between the drive component and the vacuum motion transmission component; the anti-torsion telescopic mechanism has axial extension capability, is used to coordinate movement with the axial displacement of the drive component, and bears the torque and gravity generated by the drive component.

[0009] Preferably, the drive assembly includes a brake, a coupling 1, and a ball screw 7; the anti-torsional telescopic mechanism includes two side chains, each side chain including multiple leaf blades 301, adjacent leaf blades 301 are connected by a shaft core 302, and the leaf blades 301 at both ends of the two side chains are connected by clamps 303; one clamp 303 is fixed on the fixing seat of the brake, and the other clamp 303 is fixed on the flange 4; the output shaft of the brake is rigidly connected to the ball screw 7 through the coupling 1, and when the brake rotates, it drives the ball screw 7 to rotate synchronously; the ball screw 7 cooperates with the nut fixed on the flange 4 to convert the rotational motion into axial linear motion.

[0010] Preferably, the vacuum motion transmission assembly includes a bellows assembly 5 and a thrust bearing assembly 8; the bellows assembly 5 includes a bellows 501 and a thin tube 502, and the thrust bearing assembly 8 includes a thrust bearing retaining ring 801, a double-acting thrust bearing 802, and a thrust bearing sleeve 803; one end of the double-acting thrust bearing 802 is connected to the end of the ball screw 7 and is used to bear the torque generated when the ball screw 7 rotates; the thrust bearing retaining ring 801 fixes the double-acting thrust bearing 802 inside the thrust bearing sleeve 803, so that... The thrust bearing assembly 8 moves axially together with the ball screw 7; the thrust bearing sleeve 803 is sealed to one end of the bellows 501, one end of the thin tube 502 is sealed to the flange 4, and the other end is sealed to the outer wall of the other end of the bellows 501, so that the inside of the bellows 501 is a vacuum environment and the outside is an atmospheric environment, thus achieving isolation between the atmospheric and vacuum environments; the end of the thrust bearing sleeve 803 is connected to the actuator to transmit the axial linear motion of the ball screw 7 to the actuator.

[0011] Preferably, the actuating component is a double flexible hinge support rod 6, including a long support rod 601 and a short support rod 603; the end of the thrust bearing sleeve 803 is connected to one end of the long support rod 601, the other end of the long support rod 601 is connected to the short support rod 603 through a first connector, and the end of the short support rod 603 is connected to the reflector frame through a second connector.

[0012] Preferably, both the first connector and the second connector are flexible hinges 602.

[0013] Preferably, the first connecting member is a flexible hinge 602 or a ball joint, and the second connecting member is a vertical guide rail.

[0014] Preferably, the brake is a stepper motor 2 with a brake.

[0015] Preferably, the brake is a manually adjustable brake or other type of brake.

[0016] This invention proposes an ultra-high vacuum compatible design with external drive and internal transmission: all drive components, such as stepper motors and ball screws, are placed on the atmospheric side, and motion is transmitted through a bellows feed tube, avoiding damage to the ultra-high vacuum environment caused by gas venting and particulate contamination from drive components; a segmented support rod is used and connected by two-stage flexible hinges to compensate for coaxiality and angular errors during assembly and movement, ensuring the accuracy of thrust transmission; a single motor controls the large-stroke, high-precision linear switching of the reflector within the vacuum chamber, resulting in a simple overall structure, good vacuum maintenance, and easy maintenance.

[0017] The precision switching mechanism for a large-stroke displacement ultra-high vacuum-fed reflector of this invention includes: a drive assembly placed outside the vacuum, a vacuum motion transmission assembly, and an execution assembly extending into the vacuum; the drive assembly includes a stepper motor, a coupling, and a ball screw assembly. The stepper motor drives the ball screw to output rotational motion through the coupling, which is then converted into axial linear motion through the engagement of the ball screw and a nut on the flange; the vacuum motion transmission assembly includes a thrust bearing assembly and a bellows assembly to realize motion transmission between the atmospheric side and the vacuum side; the execution assembly includes a double flexible hinge support rod assembly that directly pushes the reflector frame while compensating for the coaxiality deviation of the support rod and the angle error of the frame; the anti-torsion telescopic mechanism is fixed to the motor base and the flange respectively, and is composed of multiple blades and a shaft core, with axial telescopic capability, used to bear the motor torque and gravity, and suppress the bending deformation of the ball screw.

[0018] The advantages of this invention are as follows: This invention has several significant advantages. First, it boasts excellent compatibility with ultra-high vacuum, as the driving components are completely outside the vacuum, eliminating gas release and particulate contamination, thus maintaining ultra-high vacuum levels. Second, it features a simple and reliable structure; the single-degree-of-freedom linear motion structure is simple, reducing moving parts and lowering the risk of failure. Furthermore, this invention not only enables large stroke switching but also achieves a resolution of up to 10μm. The resolution of this invention is determined by both the motor accuracy and the ball screw lead; the stepper motor operates at 200 steps / revolution, and the ball screw lead is 2mm, resulting in a resolution of [missing information]. Therefore, the resolution can reach 10μm, meeting the requirements for nanometer-scale (nm) applications. If equipped with a speed reducer, the resolution can be further reduced; for example, with a speed reducer with a reduction ratio of 50:1, the resolution is... Meanwhile, maintenance efficiency is greatly improved, and external component failures can be directly replaced in the atmospheric environment; control and debugging are also more convenient, and switching can be completed with only the rotation control of a single motor; it has obvious cost advantages and reduces the amount of precision components used. Attached Figure Description

[0019] Figure 1 This is a diagram of the vacuum feed mechanism for XFEL.

[0020] Figure 2 Diagram of a large-stroke switching displacement vacuum feed mechanism.

[0021] Figure 3 This is a schematic diagram of the force transmission path in motion.

[0022] Figure 4 It is a double flexible hinge support rod.

[0023] Figure 5 This is a diagram of an anti-torsional telescopic mechanism.

[0024] Figure 6 This is a diagram of a four-layer stacked anti-torsional expansion mechanism.

[0025] Reference numerals: 1-Coupling, 2-Stepper motor, 3-Anti-torsion telescopic mechanism, 4-Flange, 5-Bellwall assembly, 6-Double flexible hinge support rod, 7-Ball screw, 8-Thrust bearing assembly; 301-Sheet, 302-Shaft core, 303-Clamp, 501-Bellwall, 502-Thin tube, 601-Long support rod, 602-Flexible hinge, 603-Short support rod, 801-Thrust bearing retaining ring, 802-Double thrust bearing, 803-Thrust bearing sleeve. Detailed Implementation

[0026] The present invention will now be described in further detail with reference to the accompanying drawings. The examples given are only for explaining the present invention and are not intended to limit the scope of the present invention.

[0027] Figure 2 This is a schematic diagram of a precision switching mechanism for a large-stroke displacement reflector fed into an ultra-high vacuum. The drive component uses a stepper motor 2 with a brake. The output shaft of the stepper motor 2 is rigidly connected to the ball screw 7 through a coupling 1. When the stepper motor 2 rotates, it drives the ball screw 7 to rotate synchronously. The ball screw 7 cooperates with a nut fixed on the flange 4 to convert the rotational motion into axial linear motion.

[0028] Figure 3 A schematic diagram of the motion transmission section is shown. The thrust bearing assembly 8 is located in the atmospheric environment. The double-acting thrust bearing 802 is connected to the end of the ball screw 7 to withstand the torque generated when the ball screw 7 rotates. The thrust bearing retainer ring 801 fixes the double-acting thrust bearing 802 inside the thrust bearing sleeve 803, allowing the entire thrust bearing assembly 8 to move axially along with the ball screw 7. The thrust bearing sleeve 803 is welded to the bellows 501, and the flange 4 is welded to the thin tube 502, isolating the atmosphere from the vacuum. On the vacuum side, the thrust bearing sleeve 803 is connected to the double flexible hinge support rod 6 to transmit the axial linear motion of the ball screw 7, thus achieving motion transmission.

[0029] Figure 4The diagram shows the structure of the dual flexible hinge support rod. The long support rod 601 and the short support rod 603 are connected by a flexible hinge 602, and the end of the short support rod 603 is connected to the reflector frame via the flexible hinge 602. In this structural design, the flexible hinge 602 connecting the support rods effectively compensates for coaxiality and angular deviations generated during installation and movement, ensuring that thrust is transmitted axially. The flexible hinge 602 connecting the short support rod 603 and the reflector frame further allows the frame to achieve adaptive angle adjustment within a limited range, thereby improving the accuracy and reliability of the overall system movement.

[0030] Figure 5 A schematic diagram of the anti-torsional telescopic mechanism of this invention is shown. Referring to a hinge, this structure consists of multiple leaf blades 301 and a shaft core 302, possessing a large axial stroke telescopic capability. It can coordinate with the axial displacement of the ball screw 7, providing rigid constraint without interfering with the normal feed of the ball screw 7. The clamps 303 on both sides of the mechanism are respectively fixed to the motor mount of the stepper motor 2 and the flange 4. Their main function is to bear the output torque of the stepper motor 2 and the weight of the stepper motor 2 itself when horizontally installed, thereby suppressing the bending deformation of the ball screw 7 caused by load and ensuring the accuracy and stability of the entire transmission system during operation.

[0031] The drive component in this solution can be not only a stepper motor with a brake, but also other types of brakes or manually adjustable brakes.

[0032] In this design, the flexible hinge connecting the short support rod and the reflector frame can be replaced with a vertical guide rail when the adjustment range is large.

[0033] In this design, the flexible hinge connecting the long and short support rods can be replaced with a ball joint.

[0034] The anti-torsional telescopic mechanism in this design can fold multiple layers of flaps to achieve a greater stroke. Based on the number of flaps on one side, it can stack n (n≥2) layers. For example, with n=4, ... Figure 6 As shown.

[0035] This invention is applicable not only to large-stroke displacement switching in a vacuum environment, but also to atmospheric, helium, or other environments.

[0036] Although specific embodiments of the invention have been disclosed for illustrative purposes to aid in understanding and implementing the invention, those skilled in the art will understand that various substitutions, variations, and modifications are possible without departing from the spirit and scope of the invention and the appended claims. Therefore, the invention should not be limited to the content disclosed in the preferred embodiments, and the scope of protection claimed by the invention is defined by the claims.

Claims

1. A precision switching mechanism for an ultra-high vacuum-fed, large-stroke displacement reflector, characterized in that, It includes drive components located outside the vacuum, vacuum motion transmission components, and actuation components located inside the vacuum; The driving component is connected to the vacuum motion transmission component and is used to drive the vacuum motion transmission component to move linearly along the axial direction; The vacuum motion transmission component is sealed to the execution component and is used to push the reflector frame to move linearly along the axial direction under the drive of the drive component. An anti-torsion telescopic mechanism is provided between the drive component and the vacuum motion transmission component; the anti-torsion telescopic mechanism has axial extension capability, is used to coordinate movement with the axial displacement of the drive component, and bears the torque and gravity generated by the drive component.

2. The precision switching mechanism for ultra-high vacuum-fed large-stroke displacement reflectors according to claim 1, characterized in that, The drive assembly includes a brake, a coupling, and a ball screw; the anti-torsional telescopic mechanism includes two side chains, each side chain including multiple blades, adjacent blades being connected by a shaft core, and the blades at both ends of the two side chains being connected by clamps; one clamp is fixed to the fixed seat of the brake, and the other clamp is fixed to the flange; the output shaft of the brake is rigidly connected to the ball screw through the coupling, and when the brake rotates, it drives the ball screw to rotate synchronously; the ball screw cooperates with a nut fixed to the flange to convert the rotational motion into axial linear motion.

3. The precision switching mechanism for ultra-high vacuum-fed large-stroke displacement reflectors according to claim 2, characterized in that, The vacuum motion transmission assembly includes a bellows assembly and a thrust bearing assembly. The bellows assembly includes a bellows and a thin tube. The thrust bearing assembly includes a thrust bearing retainer, a double-acting thrust bearing, and a thrust bearing sleeve. One end of the double-acting thrust bearing is connected to the end of the ball screw and is used to withstand the torque generated when the ball screw rotates. The thrust bearing retainer fixes the double-acting thrust bearing inside the thrust bearing sleeve, so that the thrust bearing assembly moves axially together with the ball screw. The thrust bearing sleeve is sealed to one end of the bellows, and one end of the thin tube is sealed to the flange and the other end is sealed to the outer wall of the other end of the bellows, so that the inside of the bellows is a vacuum environment and the outside is an atmospheric environment, achieving isolation between the atmospheric and vacuum environments. The end of the thrust bearing sleeve is connected to the actuator and is used to transmit the axial linear motion of the ball screw to the actuator.

4. The precision switching mechanism for ultra-high vacuum-fed large-stroke displacement reflectors according to claim 3, characterized in that, The actuation component is a double flexible hinge support rod, including a long support rod and a short support rod; the end of the thrust bearing sleeve is connected to one end of the long support rod, the other end of the long support rod is connected to the short support rod through a first connector, and the end of the short support rod is connected to the reflector frame through a second connector.

5. The precision switching mechanism for ultra-high vacuum-fed large-stroke displacement reflectors according to claim 4, characterized in that, Both the first connector and the second connector are flexible hinges.

6. The precision switching mechanism for ultra-high vacuum-fed large-stroke displacement reflectors according to claim 4, characterized in that, The first connecting member is a flexible hinge or ball joint, and the second connecting member is a vertical guide rail.

7. The precision switching mechanism for ultra-high vacuum-fed large-stroke displacement reflectors according to claim 2, characterized in that, The brake is a stepper motor with a brake.

8. The precision switching mechanism for ultra-high vacuum-fed large-stroke displacement reflectors according to claim 2, characterized in that, The brake is a manually adjustable brake or other type of brake.

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