A high-precision rotating shaft system for a rapid-scanning X-ray absorption fine structure spectroscopy monochromator

Abstract

The present invention provides a high-precision rotating shaft system for a rapid-scanning X-ray absorption fine structure spectroscopy monochromator. The driving mode of the rapid-scanning monochromator is changed from the traditional mechanical transmission to direct driving by a torque motor, which improves the transmission efficiency, eliminates the transmission error, reduces mechanical vibration. The high-precision incremental encoder is directly connected to the motor drive plate to ensure the measurement accuracy of the rotation angle of the rotation system. The rotating shaft system is lightened to reduce the rotational inertia of the system while ensuring the stiffness, and improve the safety factor of operation.

Description

Technical Field

[0001] The present invention belongs to the field of synchrotron radiation machinery, and particularly relates to a high-precision rotating shaft system for a fast-scanning X-ray absorption fine structure spectroscopy monochromator. Background Art

[0002] The fast-scanning monochromator rotating shaft system is applied to the X-ray absorption spectroscopy station in high-energy synchrotron radiation light sources, driving the crystal assembly to perform rapid reciprocating motion to rapidly and reciprocally change the Bragg angle, that is, the diffraction energy, so as to complete the acquisition of an absorption spectrum within a short time and achieve a rapid and repeated spectrum acquisition process.

[0003] A direct-drive multi-channel monochromator includes a direct-drive motor, a magnetic fluid, and a crystal monochromator; the motor rotating shaft of the direct-drive motor is connected to the atmospheric-end rotating shaft of the magnetic fluid sealing device, and the vacuum-end rotating shaft of the magnetic fluid sealing device is connected to the crystal monochromator to drive the crystal monochromator to rotate around the rotating shaft; wherein the rotating shafts of the direct-drive motor and the magnetic fluid are consistent.

[0004] In existing monochromators, the rotation mechanism mostly uses servo motors, and couplings are mostly used to connect the motor and the rotating shaft, and ball screws (gears, trapezoidal screws) are used as transmission units. The disadvantages of these structures are that the transmission chain is relatively long, there are transmission errors and time lags between transmission elements, and the axes of all components must be ensured to coincide with each other during installation, otherwise torsional errors are likely to occur. At the same time, transmission elements such as screws rely on the rolling of balls in rolling grooves to transmit lateral displacement, there is backlash, the transmission error is large, the friction and wear are serious, and looseness occurs after long-term operation. This series of problems lead to difficult installation, low overall precision, and affect the overall dynamic performance of the monochromator. Summary of the Invention

[0005] To solve the above technical problems, the present invention provides a high-precision rotating shaft system for a fast-scanning X-ray absorption fine structure spectroscopy monochromator, changing the driving mode of the fast-scanning monochromator from traditional mechanical transmission to direct driving by a torque motor, improving the transmission efficiency, eliminating transmission errors, reducing mechanical vibrations, directly connecting a high-precision incremental encoder to the motor drive plate to ensure the measurement accuracy of the rotation angle of the rotation system, and performing lightweight treatment on the rotating shaft to reduce weight while ensuring stiffness.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] A high-precision rotating shaft system for a rapid-scanning X-ray absorption fine structure spectroscopy monochromator, comprising a bearing retaining ring, a drive plate, an external baffle, a motor, a first bracket, a second bracket, a bearing sleeve, a magnetic fluid protection plate, magnetic fluid, a rotating shaft, a cavity back plate, a motor sleeve, an internal baffle, bearings, bearing outer ring retaining rings, compression nuts, a first O-ring, a second O-ring, a third O-ring, and a fourth O-ring; circular shaft ends are provided at both ends of the rotating shaft, and positioning steps are provided on the surface. The rotating shaft is in interference fit with four pairs of back-to-back angular contact bearings through the bearing positioning steps. The bearings are in clearance fit with the bearing sleeves. One end of the bearing sleeve is connected to the bearing outer ring retaining ring, and the bearing outer ring retaining ring is in close contact with the bearing outer ring. The bearing inner ring is in close contact with the bearing retaining ring. The compression nut is used to squeeze the bearing retaining ring to provide a preload for the bearings. The other end of the bearing sleeve is connected to the cavity back plate by bolts. The cavity back plate is connected to the first bracket and the second bracket. The other side of the first bracket is connected to one end of the motor sleeve through an end face positioning step. The motor sleeve is connected to the external baffle. A positioning step is provided on the inner ring of the motor sleeve, and the motor stator is connected to the motor sleeve by bolts through the inner ring positioning step. The other end of the motor stator is connected to the internal baffle. The motor rotor is connected to the drive plate. The drive plate is connected to the rotating shaft by anti-loosening bolts and positioning pins; one end of the rotating shaft on the atmosphere side is sealed with a sealing end cover, and the other end is connected to the vacuum chamber. The contact surfaces between the magnetic fluid and the rotating shaft are sealed with the first and second O-rings, and the second O-ring is also provided between the contact surfaces of the magnetic fluid and the bearing sleeve. One end of the bearing sleeve on the vacuum side is connected to the magnetic fluid protection plate.

[0008] Furthermore, the inside of the rotating shaft is hollow, and the inner surface is coated. One end is connected to the sealing end cover, and the contact surface is provided with a fourth O-ring. A positioning hole is provided in the center of the sealing end cover, and the center of the hole coincides with the center of the rotating shaft; the other end of the rotating shaft is connected to the vacuum chamber. The magnetic fluid is sleeved on the rotating shaft, and the center line of the magnetic fluid coincides with the center line of the rotating shaft. The first and second O-rings are provided between the contacts. The bearings and the contact surfaces of the magnetic fluid are also provided with the second O-ring to achieve vacuum sealing.

[0009] Furthermore, the bearing sleeve is in clearance fit with the bearings, and their rotation centers are all the same as that of the rotating shaft. The end face of the bearing sleeve extending into the vacuum side is connected to the magnetic fluid protection plate to provide radiation protection for the magnetic fluid.

[0010] Furthermore, the inner end face of the drive plate is connected to the positioning step of the rotating shaft, and positioning steps are provided on the outer end face and are connected to the motor rotor by bolts. The motor stator is fixed on the motor sleeve. When the motor runs, the torque is transmitted to the inside of the vacuum through the drive plate, the rotating shaft, and the magnetic fluid, realizing the torque transmission from the atmosphere to the vacuum.

[0011] Further, the inner end face of the drive plate is connected to the positioning step of the rotating shaft, and an annular boss is provided at the outer root. The incremental encoder disk is buckled on the annular boss, and two reading heads are respectively fixed on the external baffle for angle position monitoring, so as to achieve the purpose of real-time monitoring of angular displacement.

[0012] Further, a positioning step is provided on the surface of the rotating shaft. The bearing positioning step is in interference fit with the four-row back-to-back angular contact bearings. The bearing is in clearance fit with the bearing sleeve. The bearing sleeve is connected to the cavity back plate through the positioning step, and a third O-ring is provided on the contact surface. The rotation centers of the rotating shaft and the cavity back plate are consistent, so as to achieve the precision transfer from the rotating shaft to the cavity back plate.

[0013] Further, anti-loosening bolts and positioning pins are provided on the contact surface between the rotating shaft and the drive plate. The bearing is installed on the rotating shaft, and the inner ring snap ring is extruded by the compression nut to apply a pre-tightening force to the bearing, so as to achieve the purpose of preventing loosening.

[0014] Further, the inner end face of the drive plate is connected to the rotating shaft, and the outer end face is connected to the limit block. When the rotating shaft works, the drive plate rotates together with the rotating shaft. At the specified position, the limit block contacts the limit switch, and the limit switch operates for primary limit. When continuing to rotate, the limit block collides with the external baffle for secondary limit, so as to achieve multiple safety protections for the rotating components.

[0015] Further, the inner end face of the internal baffle is connected to the motor stator, and the outer end face is in the shape of a square gear. The square gear piece is bolted to the motor sleeve. There is a boss inside the external baffle, and the boss is staggeredly matched with the end face of the external square gear of the internal baffle. There is a gap between the external baffle and the internal baffle. When the limit block impacts the external baffle, the impact force directly acts on the motor sleeve, avoiding the impact force on the motor stator and playing a role in protecting the motor.

[0016] Further, the stator of the motor is connected to the motor sleeve, and a cooling water channel is opened on the outside of the stator. A heat-conducting copper sheet is provided between the motor sleeve and the bearing sleeve to take away part of the heat generated by the rotation of the bearing.

[0017] Beneficial effects:

[0018] In the mechanical design of the present invention, a multiple positioning structure is provided to achieve coaxiality transfer and ensure the overall rotation accuracy; the direct drive motor directly drives the rotating shaft part to rotate with a large torque, reducing the transmission error; the magneto-fluid component realizes vacuum sealing and radiation protection;

[0019] Atmospheric to vacuum torque transmission, with anti-loosening treatment at the rotating connection part; one end of the oxygen-free copper sheet is connected to the motor sleeve, and the other end is connected to the bearing sleeve. While the motor is water-cooled, it takes away part of the heat generated by the rotation of the bearing; a limit block is installed on the transmission plate, and the limit switch is contacted through the limit block to collide with the external baffle to achieve double limit; the internal baffle positions the motor stator, and the external baffle bears the impact force generated by the work of the limit block, reducing the damage to the motor stator and realizing motor protection.

[0020] The rotating shaft and rotating parts of the present invention are both light-weighted to reduce the moment of inertia while ensuring stiffness. The torque motor directly drives the rotating shaft part to rotate, reducing the transmission error and improving the transmission efficiency; the magnetic fluid seal realizes the rotating transmission from the atmosphere to the vacuum while ensuring the vacuum degree; a positioning mechanism for multi-precision transmission is set on the mechanical structure to ensure the coaxiality of the zero-degree parts, improve the transmission precision, and reduce the installation difficulty; the rotating connection part is treated with anti-loosening to improve the transmission precision and increase the service life. Brief Description of the Drawings

[0021] Figure 1 is a high-precision rotating shaft system for a monochromator;

[0022] Figure 2 is a schematic diagram of the seal between the atmospheric side and the vacuum side of the main shaft system;

[0023] Figure 3 is a schematic diagram of the seal and anti-loosening of the rotating shaft;

[0024] Figure 4 is a schematic diagram of motor cooling and mechanical limit. Detailed Embodiments

[0025] In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0026] Such as Figures 1-4As shown in the figure, a high-precision rotating shaft system of a fast-scanning X-ray absorption fine structure spectroscopy monochromator according to the present invention includes a bearing retaining ring 1, a transmission plate 2, an external baffle 3, a motor 4, a first bracket 5, a second bracket 11, a bearing sleeve 6, a magnetic fluid protection plate 7, magnetic fluid 8, a rotating shaft 9, a cavity back plate 10, a motor sleeve 12, an internal baffle 13, a bearing 14, a bearing outer ring retaining ring 15, a compression nut 16, a first O-ring 17, a second O-ring 18, a third O-ring 19, a fourth O-ring 20, and a fifth O-ring 25. Circular shaft ends are provided at both ends of the rotating shaft 9, and positioning steps are provided on the surface. The rotating shaft is in interference fit with four rows of back-to-back angular contact bearings 14 through the bearing positioning steps. The bearing 14 is in clearance fit with the bearing sleeve 6. One end of the bearing sleeve 6 is connected to the bearing outer ring retaining ring 15, and the bearing outer ring retaining ring 15 is in close contact with the outer ring of the bearing 14. The inner ring of the bearing 14 is in close contact with the bearing retaining ring 1. The compression nut 16 is used to squeeze the bearing retaining ring 1 to provide a pre-tightening force for the bearing. The other end of the bearing sleeve 6 is bolted to the cavity back plate 10. The cavity back plate 10 is threadedly connected to the first bracket 5, and the first bracket 5 and the second bracket 11 are welded together. The other side of the first bracket 5 is connected to one end of the motor sleeve 12 through an end face positioning step. The motor sleeve 12 is connected to the external baffle 3. A positioning step is provided on the inner ring of the motor sleeve 12, and the stator of the motor 4 is bolted to the rotating shaft 9 through the inner ring positioning step. The other end of the stator of the motor 4 is connected to the internal baffle 13. The rotor of the motor 4 is connected to the transmission plate 2. The transmission plate 2 is connected to the rotating shaft 9 through anti-loosening bolts 22 and positioning pins 23.

[0027] One end of the rotating shaft 9 located on the atmosphere side is sealed with a sealing end cover 24, and the other end is connected to the vacuum chamber. The contact surfaces between the magnetic fluid 8 and the rotating shaft 9 are sealed with a first O-ring 17 and a third O-ring 19, and a second O-ring 18 is also provided for sealing between the contact surfaces of the magnetic fluid 8 and the bearing sleeve 6. One end of the bearing sleeve 6 on the vacuum side is connected to the magnetic fluid protection plate 7.

[0028] The inside of the rotating shaft 9 is hollow, and the inner surface is coated. One end is connected to the sealing end cover 24, and a fifth O-ring 25 is provided on the contact surface. A positioning hole is provided in the center of the sealing end cover 24, and the center of the hole coincides with the center of the rotating shaft 9. The other end of the rotating shaft 9 is connected to the vacuum chamber. The magnetic fluid 8 is sleeved on the rotating shaft 9, and the center line of the magnetic fluid 8 coincides with the center line of the rotating shaft 9. A first O-ring 17 and a third O-ring 19 are provided between the contacts, and a second O-ring 18 is also provided between the bearing sleeve 8 and the magnetic fluid to achieve vacuum sealing.

[0029] The bearing sleeve 6 is in clearance fit with the bearing 14, and their rotation centers are both consistent with the rotating shaft 9. The end face of the bearing sleeve 8 extending into the vacuum side is connected to the magnetic fluid protection plate 7 to provide radiation protection for the magnetic fluid 8.

[0030] The inner end face of the transmission plate 2 is connected to the positioning step of the rotating shaft 9, and the outer end face is provided with a positioning step and is connected to the rotor of the motor 4 by bolts. The stator of the motor 4 is fixed on the motor sleeve 12. When the motor 4 operates, the torque is transmitted to the vacuum interior through the transmission plate 2, the rotating shaft 9, and the magnetorheological fluid 8, realizing the torque transmission from the atmosphere to the vacuum.

[0031] The inner end face of the transmission plate 2 is connected to the positioning step of the rotating shaft 9, and an annular boss is provided at the outer root. The disk of the incremental encoder 21 is buckled on the annular boss, and two reading heads are respectively fixed on the external baffle 3 for angle position monitoring, achieving the purpose of real-time monitoring of angular displacement.

[0032] The surface of the rotating shaft 9 is provided with a positioning step, and is in interference fit with the four-row back-to-back angular contact bearings 14 through the bearing positioning step. The bearings 14 are in clearance fit with the bearing sleeve 6. The bearing sleeve 6 is connected to the cavity back plate 10 through the positioning step, and a fourth O-ring 20 is provided on the contact surface. The rotation centers of the rotating shaft 9 and the cavity back plate 10 are consistent, realizing the accuracy transmission from the rotating shaft 9 to the cavity back plate 10.

[0033] The contact surface between the rotating shaft 9 and the transmission plate 2 is provided with anti-loosening bolts 22 and positioning pins 23. The bearings 14 are installed on the rotating shaft 9, and the inner ring snap ring is extruded by the compression nut 16 to apply a pre-tightening force to the bearings, achieving the purpose of preventing loosening.

[0034] The inner end face of the transmission plate 2 is connected to the rotating shaft 9, and the outer end face is connected to the limit block 26. When the rotating shaft works, the transmission plate 2 rotates together with the rotating shaft 9. At a specified position, the limit block 26 contacts the limit switch 27, and the limit switch 27 operates for primary limit. When continuing to rotate, the limit block 26 collides with the external baffle 3 for secondary limit, realizing multiple safety protections for the rotating components.

[0035] The inner end face of the internal baffle 13 is connected to the motor stator, and the outer end face is in the shape of a square gear. The square gear piece is connected to the motor sleeve by bolts. There is a boss inside the external baffle 3, and the boss and the outer square gear end face of the internal baffle 13 are staggeredly matched. There is a gap between the external baffle 3 and the internal baffle 13. When the limit block 26 impacts the external baffle 3, the impact force directly acts on the motor sleeve, avoiding the impact force on the motor stator and playing a role in protecting the motor.

[0036] The end face of the stator of the motor 4 is threadedly connected to the boss of the motor sleeve 12. A cooling water channel 28 is opened on the outside of the stator to cool the motor. A heat-conducting copper sheet 29 is provided between the motor sleeve 12 and the bearing sleeve 6 to take away part of the heat generated by the rotation of the bearings.

[0037] Those skilled in the art can easily understand that the above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims

1. A high-precision rotating shaft system for a rapid-scanning X-ray absorption fine structure spectroscopy monochromator, characterized in that: It includes a bearing retaining ring (1), a drive plate (2), an external baffle (3), a motor (4), a first bracket (5), a second bracket (11), a bearing sleeve (6), a magnetorheological fluid protection plate (7), magnetorheological fluid (8), a rotating shaft (9), a cavity back plate (10), a motor sleeve (12), an internal baffle (13), a bearing (14), an outer bearing ring retaining ring (15), a compression nut (16), a first O-ring (17), a second O-ring (18), a third O-ring (19), a fourth O-ring (20), a fifth O-ring (25); circular shaft ends are provided at both ends of the rotating shaft (9), and positioning steps are provided on the surface. The rotating shaft is in interference fit with four rows of back-to-back angular contact bearings (14) through the bearing positioning steps. The bearing (14) is in clearance fit with the bearing sleeve (6). One end of the bearing sleeve (6) is connected to the outer bearing ring retaining ring (15), and the outer bearing ring retaining ring (15) is in close contact with the outer ring of the bearing (14). The inner ring of the bearing (14) is in close contact with the bearing retaining ring (1). The compression nut (16) is used to squeeze the bearing retaining ring (1) to provide a pre-tightening force for the bearing. The other end of the bearing sleeve (6) is connected to the cavity back plate (10) by bolts. The cavity back plate (10) is threadedly connected to the first bracket (5), and the first bracket (5) and the second bracket (11) are welded together. The other side of the first bracket (5) is connected to the motor sleeve (12) through an end face positioning step. The motor sleeve (12) is connected to the external baffle (3). A positioning step is provided on the inner ring of the motor sleeve (12), and the stator of the motor (4) is bolted to the motor sleeve (12) through the inner ring positioning step. The other end of the stator of the motor (4) is connected to the internal baffle (13). A cooling water channel (28) is provided on the outside of the stator of the motor (4). The rotor of the motor (4) is connected to the drive plate (2), and the drive plate (2) is connected to the rotating shaft (9) through anti-loosening bolts (22) and positioning pins (23); one end of the rotating shaft (9) located on the atmosphere side is sealed with a sealing end cover (24), and the other end is connected to the vacuum chamber. A first O-ring (17) and a third O-ring (19) are provided between the magnetorheological fluid (8) and the rotating shaft (9). A second O-ring (18) is also provided on the contact surface between the bearing sleeve (6) and the magnetorheological fluid. One end of the bearing sleeve (6) on the vacuum side is connected to the magnetorheological fluid protection plate (7).

2. A high-precision rotating shaft system for a rapid-scanning X-ray absorption fine structure spectroscopy monochromator according to claim 1, characterized in that: The inside of the rotating shaft (9) is hollow, and the inner surface is coated. One end is connected to the sealing end cover (24), and a fifth O-ring (25) is provided on the contact surface. A positioning hole is provided in the center of the sealing end cover (24), and the center of the hole is consistent with the center of the rotating shaft (9); the other end of the rotating shaft (9) is connected to the vacuum chamber. The magnetorheological fluid (8) is sleeved on the rotating shaft (9), and the center line of the magnetorheological fluid (8) is consistent with the center line of the rotating shaft (9). A first O-ring (17) and a third O-ring (19) are provided between them. A second O-ring (18) is also provided on the contact surface between the bearing sleeve (6) and the magnetorheological fluid to achieve vacuum sealing.

3. A high-precision rotating shaft system for a rapid-scanning X-ray absorption fine structure spectroscopy monochromator according to claim 1, characterized in that: The bearing sleeve (6) is in clearance fit with the bearing (14), and their rotation centers are both consistent with the rotating shaft (9). The bearing sleeve (6) extends into the vacuum side end face and is connected to the magnetohydrodynamic protection plate (7) to provide radiation protection for the magnetohydrodynamic (8).

4. A high-precision rotating shaft system for a rapid-scanning X-ray absorption fine structure spectroscopy monochromator according to claim 1, wherein: The inner end face of the transmission plate (2) is connected to the positioning step of the rotating shaft (9), and the outer end face is provided with a positioning step and is bolted to the rotor of the motor (4). The stator of the motor (4) is fixed on the motor sleeve (12). When the motor (4) operates, the torque is transmitted to the interior of the vacuum through the transmission plate (2), the rotating shaft (9), and the magnetohydrodynamic (8), achieving torque transmission from the atmosphere to the vacuum.

5. A high-precision rotating shaft system for a rapid-scanning X-ray absorption fine structure spectroscopy monochromator according to claim 1, characterized in that: The inner end face of the transmission plate (2) is connected to the positioning step of the rotating shaft (9), and an annular boss is provided at the outer root. The code disk of the incremental encoder (21) is buckled on the annular boss, and the two reading heads are respectively fixed on the external baffle (3) for angle position monitoring to achieve the purpose of real-time monitoring of angular displacement.

6. A high-precision rotating shaft system for a rapid-scanning X-ray absorption fine structure spectroscopy monochromator according to claim 1, characterized in that: The surface of the rotating shaft (9) is provided with a positioning step, and is in interference fit with the four-row back-to-back angular contact bearing (14) through the bearing positioning step. The bearing (14) is in clearance fit with the bearing sleeve (6). The bearing sleeve (6) is connected to the cavity back plate (10) through the positioning step, and a fourth O-ring (20) is provided on the contact surface. The rotation centers of the rotating shaft (9) and the cavity back plate (10) are consistent to achieve precision transmission from the rotating shaft (9) to the cavity back plate (10).

7. A high-precision rotating shaft system for a rapid-scanning X-ray absorption fine structure spectroscopy monochromator according to claim 1, characterized in that: The contact surface between the rotating shaft (9) and the transmission plate (2) is provided with anti-loosening bolts (22) and positioning pins (23). The bearing (14) is installed on the rotating shaft (9), and the inner ring retaining ring is extruded by the compression nut (16) to apply a pre-tightening force to the bearing to achieve the purpose of preventing loosening.

8. A high-precision rotating shaft system for a rapid-scanning X-ray absorption fine structure spectroscopy monochromator according to claim 1, characterized in that: The inner end face of the transmission plate (2) is connected to the rotating shaft (9), and the outer end face is connected to the limit block (26). When the rotating shaft works, the transmission plate (2) rotates together with the rotating shaft (9). At a specified position, the limit block (26) contacts the limit switch (27), and the limit switch (27) operates for primary limit. When continuing to rotate, the limit block (26) collides with the external baffle (3) for secondary limit to achieve multiple safety protections for the rotating components.

9. A high-precision rotating shaft system for a rapid-scanning X-ray absorption fine structure spectroscopy monochromator according to claim 1, characterized in that: The inner end face of the internal baffle (13) is connected to the motor stator, and the outer end face is in the shape of a square gear. The square gear piece is bolted to the motor sleeve. There is a boss inside the external baffle (3), and the boss is in staggered fit with the end face of the square gear on the outside of the internal baffle (13). There is a gap between the external baffle (3) and the internal baffle (13). When the limit block (26) impacts the external baffle (3), the impact force directly acts on the motor sleeve, avoiding the impact force on the motor stator and playing a role in protecting the motor.

10. A high-precision rotating shaft system for a rapid-scanning X-ray absorption fine structure spectroscopy monochromator according to claim 1, characterized in that: The end face of the stator of the motor (4) is connected to the boss of the motor sleeve through threads. Cooling water channels (28) are opened on the outside of the stator to cool the motor. A heat-conducting copper sheet (29) is provided between the motor sleeve (12) and the bearing sleeve (6) to take away part of the heat generated by the rotation of the bearing.

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