Double-shaft direct-drive goniometer for X-ray diffractometer

Abstract

The double-shaft direct-drive goniometer comprises a shell, an inner shaft and an outer shaft, the inner shaft and the outer shaft are rotationally matched with the shell, the inner shaft is located on the inner side of the outer shaft, and a first direct-drive motor rotor and a second direct-drive motor rotor are rotationally connected into the shell. The first direct-drive motor rotor and the second direct-drive motor rotor are fixedly connected with the inner shaft and the outer shaft respectively. According to the invention, the first direct-drive motor stator and the second direct-drive motor stator can respectively drive the first direct-drive motor rotor to drive the inner shaft and the second direct-drive motor rotor to drive the outer shaft to respectively rotate by taking the axis of the inner shaft and the axis of the second direct-drive motor rotor as a rotating shaft, so that the inner shaft and the outer shaft are directly driven; the problem that the precision is reduced due to transmission back clearance and transmission contact is avoided, and the rotation positioning precision and the rotation repeatability positioning precision are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of X-ray diffractometers, and more particularly to a dual-axis direct-drive goniometer for X-ray diffractometers. Background Art

[0002] Goniometers have unique diffraction geometry requirements. In an X-ray diffractometer, the sample is fixed on the central axis (θ axis) of the goniometer circle, and the optical engine and detector are distributed on the radial circumference. In the conventional structure, the optical engine remains stationary, the sample can rotate along the central axis (θ axis), and the detector moves synchronously along the goniometer circumference at twice the rotation speed of the sample to ensure that the angle between the optical engine light and the sample plane is always equal to the angle between the diffracted light and the sample plane. The grain orientation in the sample is chaotic. Among the large number of grains irradiated by the human ray on the sample surface, only a certain (HKL) parallel to the free surface may be reflected (diffracted), and the reflection is instantaneous. At this moment, dHKL (the face grid spacing of the crystal plane), λ, and θ satisfy the Bragg equation relationship, where θ is the angle between the human ray or the reflected line and the crystal plane (i.e., the sample surface), and the detector forms an angle of 2θ with the extension of the incident ray. During the change of θ and 2θ, the detector will receive strong diffraction rays at certain specific positions. θ and 2θ usually increase from low to high, so the spacing between the crystal planes selected to reflect X-rays must be from large to small.

[0003] In the X-ray diffractometer system, the goniometer is responsible for the most important angle measurement and component driving functions. The positioning accuracy and repeatability of the angle measurement largely determine the quality of the diffraction results. The repeatability of the goniometer has become an important indicator to distinguish the performance of X-ray diffractometers of different brands and models. At present, the rotation repeatability of X-ray diffractometers from foreign companies such as Bruker, Rigaku, and PANalytical has reached 0.0001 degrees, and the rotation positioning accuracy can reach up to 0.001 degrees. However, the accuracy of domestic X-ray diffractometers is generally low, or the accuracy performance is poor after long-term use.

[0004] The goniometer is mainly composed of four parts: drive mechanism, transmission mechanism, feedback mechanism and housing. Each manufacturer has differentiated designs for the above four parts. At present, the main technical difficulty is that the backlash error and manufacturing error of the transmission mechanism have the greatest impact on the accuracy of the goniometer. The commonly used transmission mechanism is the worm gear structure, and the traditional worm gear has a repeatability positioning accuracy of about 0.005 degrees due to the existence of backlash, which is far lower than 0.0001 degrees. On this basis, some improved technologies have been born, such as: zero backlash worm gear, the disadvantage is that the manufacturing technology is difficult and the foreign procurement price is very expensive; variable lead worm gear, the disadvantage is that there is still backlash error, and the repeatability positioning accuracy is still difficult to reach 0.0001 degrees; cam roller structure, cam roller technology is monopolized by Japan, and installation requires grinding and matching, which is difficult to apply; double worm structure, the disadvantage is that it is difficult to control the disadvantages, and the long-term stability needs to be verified. In summary, the above transmission methods all have the following disadvantages: transmission contact friction; installation preload; low transmission efficiency; low positioning accuracy; low repeatability positioning accuracy.

[0005] Patent document with patent announcement number CN117871567A discloses a method for improving the angle measurement accuracy of a vertical X-ray diffractometer and an angle measurement positioning device, in which a dual optical encoder is directly installed on the rotating shaft of the ray tube and the detector, and the incident angle θ of the ray tube and the receiving angle θ of the detector are directly measured by the dual optical encoder. This solution eliminates the angle error of the traditional motor transmission ratio system, and adopts an angle measurement positioning device that directly installs a dual optical encoder (grating drum, reading head) on the rotating shaft of the ray tube and the rotating shaft of the detector, thereby ensuring the quality reliability of the product, but it still uses transmission components for transmission, and cannot eliminate the structural error caused by the transmission structure. Summary of the invention

[0006] The technical problem to be solved by the present invention is how to improve the accuracy of the goniometer.

[0007] The present invention solves the above technical problems through the following technical means: a dual-axis direct-drive goniometer for an X-ray diffractometer, comprising a shell and an inner shaft and an outer shaft rotatably matched with the shell, the inner shaft being located on the inner side of the outer shaft, a direct-drive motor mover 1 and a direct-drive motor mover 2 being rotatably connected in the shell, the direct-drive motor mover 1 and the direct-drive motor mover 2 being fixedly connected to the inner shaft and the outer shaft respectively, a direct-drive motor stator 1 and a direct-drive motor stator 2 being also fixedly connected in the shell, the direct-drive motor stator 1 and the direct-drive motor stator 2 being able to respectively drive the direct-drive motor mover 1 to drive the inner shaft and the direct-drive motor mover 2 to drive the outer shaft to rotate with their axes as rotating axes respectively.

[0008] As a preferred technical solution, the inner shaft is coaxial with the outer shaft axis, and a gap is left between the inner wall of the outer shaft and the outer wall of the inner shaft.

[0009] As a preferred technical solution, the shell includes a shell one and a shell two which are fixedly connected, the inner shaft is rotationally connected to the shell two, and the outer shaft is rotationally connected to the shell one.

[0010] As a preferred technical solution, the inner shaft and the outer shaft are both rotatably connected to the housing via bearings, the two bearing inner rings are respectively fixedly connected to the inner shaft and the outer shaft, and the two bearing outer rings are both fixedly connected to the housing.

[0011] As a preferred technical solution, a circular grating and a limit block are provided at one end of the inner shaft, the circular grating is coaxial with the axis of the inner shaft, the end face of the inner shaft is provided with a limit block, and the inner wall of the shell is provided with a limit baffle matched with the limit block.

[0012] As a preferred technical solution, a circular grating 2 and a limit block are provided at one end of the outer shaft, the circular grating 2 is fixedly connected to one end of the outer shaft, another limit block is fixedly connected to the end face of the outer shaft, and a limit baffle matching the limit block is provided on the inner wall of the shell.

[0013] As a preferred technical solution, the inner shaft is rotationally connected to the second shell, and the outer shaft is rotationally connected to the first shell.

[0014] As a preferred technical solution, the inner shaft passes through the inner hole of the outer shaft and is connected to an external device, and the external device includes an optical machine or a detector or a test sample.

[0015] As a preferred technical solution, the circular grating 1 is electrically connected to the stator 1 of the direct drive motor.

[0016] As a preferred technical solution, the second circular grating is electrically connected to the second stator of the direct drive motor.

[0017] The beneficial effects of the present invention are:

[0018] (1) In the present invention, the direct-drive motor stator 1 and the direct-drive motor stator 2 can respectively drive the direct-drive motor mover 1 to drive the inner shaft and the direct-drive motor mover 2 to drive the outer shaft to rotate with their axes as the rotating axes, and directly drive the inner shaft and the outer shaft. Compared with the prior art, the transmission mechanism is eliminated, the problem of transmission backlash and transmission contact reducing the accuracy is avoided, and the rotation positioning accuracy and rotation repeatability positioning accuracy are improved.

[0019] (2) In the present invention, by coaxially arranging the inner axis and the outer axis with a gap therebetween, rotation can be provided for the combination of the optical machine and the detector, and rotation can also be provided for any two of the optical machine, the detector and the sample to meet the functional requirements of different scenarios of the X-ray diffractometer, thereby improving the applicability of the device. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1A front view schematic diagram of the structure provided by an embodiment of the present invention;

[0021] Figure 2 The embodiment of the present invention provides Figure 1 AA cross-sectional structural diagram;

[0022] Figure 3 A schematic diagram of a rear view structure provided by an embodiment of the present invention;

[0023] Figure numbers: 1. Shell one; 2. Shell two; 3. Inner shaft; 4. Stator one of direct drive motor; 5. Mover one of direct drive motor; 6. Turntable bearing one; 7. Limit block one; 8. Limit block two; 9. Electric limit one; 10. Electric limit two; 11. Circular grating one; 12. Outer shaft; 13. Stator two of direct drive motor; 14. Mover two of direct drive motor; 15. Turntable bearing two; 16. Circular grating two; 17. Limit block three; 18. Limit block four; 19. Electric limit three; 20. Electric limit four. DETAILED DESCRIPTION

[0024] 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.

[0025] See also Figure 1 , Figure 2 A dual-axis direct-drive goniometer for an X-ray diffractometer comprises a housing, an inner shaft 3 and an outer shaft 12 rotatably matched with the housing, and a driver, wherein the inner shaft 3 is located inside the outer shaft 12. In this embodiment, the housing comprises a housing 1 and a housing 2, wherein a direct-drive motor mover 15 and a direct-drive motor mover 214 are rotatably connected in the housing 22 and the housing 1, respectively, wherein the outer shaft 12 is located in the housing 1, the inner shaft 3 is located in the housing 2, and extends toward the housing 1 and extends out of the housing 1, the direct-drive motor mover 15 is fixedly connected to the inner shaft 3, a direct-drive motor mover 14 is arranged outside the direct-drive motor mover 15, and the direct-drive motor mover 14 is fixedly connected to the housing 22. After power is turned on, the direct-drive motor stator 4 can drive the direct-drive motor mover 15 to drive the inner shaft 3 to rotate with its axis as the rotating shaft;

[0026] A direct-drive motor stator 2 13 is provided on the outside of the direct-drive motor mover 2 14. The direct-drive motor stator 2 13 is fixedly connected to the housing 1. The driver is electrically connected to the direct-drive motor stator 1 4 and the direct-drive motor stator 2 13. After power is turned on, the direct-drive motor stator 2 13 can drive the direct-drive motor mover 2 14 to drive the outer shaft 12 to rotate with its axis as the axis. The inner shaft 3 is coaxial with the axis of the outer shaft 12, and a gap is left between the inner wall of the outer shaft 12 and the outer wall of the inner shaft 3 to prevent contact interference, resulting in a decrease in accuracy, or the inner shaft 3 and the outer shaft 12 rotate in coordination.

[0027] See also Figure 2 The housing 1 and the housing 2 are detachably connected, such as being fastened by bolts; the inner shaft 6 is rotatably connected to the housing 2 through a turntable bearing 1 6, wherein the outer ring of the turntable bearing 1 6 is fixedly connected to the housing 2 2 by screws, and the inner ring is fixedly connected to the inner shaft 1 by screws; the outer shaft 12 is rotatably connected to the housing 1 through a turntable bearing 2 15, wherein the outer ring of the turntable bearing 2 15 is fixedly connected to the housing 1 by screws, and the inner ring is fixedly connected to the outer shaft 12 by screws, thereby ensuring the rotation accuracy.

[0028] See also Figure 2 The outer shaft 12 is coaxial with the axis of the inner shaft 3, and an inner hole is opened on the outer shaft 12. The inner shaft 3 passes through the inner hole of the outer shaft 12 and is connected to an external device. The external device includes an optical machine or a detector or a test sample. The inner shaft 3 and the outer shaft 12 can provide rotation for the combination of the optical machine and the detector, and can also provide rotation for any two of the optical machine, the detector and the sample to meet the functional requirements of different scenarios of the X-ray diffractometer, thereby improving the applicability of the device.

[0029] See also Figure 1 , Figure 3 The tail end of the inner shaft 3 is fixedly connected with a circular grating 11 and a limit block, the circular grating 11 is coaxial with the axis of the inner shaft 3, and the limit block is fixedly connected to the end face of the outer shaft 12. In this embodiment, the limit block includes a limit block 1 7 and a limit block 2 8. The limit block 1 7 and the limit block 2 8 constitute a mechanical limit for limiting the stroke of the inner shaft 3, thereby limiting the rotation area of ​​the inner shaft 3. The inner wall of the housing 2 2 is fixedly connected with a limit block 7 and a limit block 2 8. The two limit blocks are respectively used to limit the limit block 1 7 and the limit block 2 The second stop block 8 is used for limiting; the head end of the outer shaft 12 is fixedly connected with a circular grating 2 16 and a stop block, the circular grating 2 16 is coaxial with the axis of the outer shaft 12, and the end face of the outer shaft 12 is fixedly connected with another stop block, the other stop block includes a stop block 3 17 and a stop block 4 18, and the inner wall of the housing 1 is also fixedly connected with a stop block 3 17 and a stop block 4 18. The two stop blocks are respectively used for the stop block 3 17 and the stop block 4 18, thereby constituting a mechanical limit for limiting the stroke of the outer shaft 12;

[0030] The tail end of the inner shaft 3 is also fixedly connected with an electric limit 1 9 and an electric limit 2 10, and the end face of the outer shaft 12 is also fixedly connected with an electric limit 3 19 and an electric limit 4 20. In this embodiment, the role of the electric limit is to ensure that the position movement of the inner shaft 3 and the outer shaft 12 will not exceed the preset position during the movement, thereby playing a role of limit protection.

[0031] Usage: After the driver energizes the direct-drive motor stator 4, it drives the direct-drive motor stator 1 5 to drive the inner shaft 3 to rotate, and the circular grating 1 11 is used as the position feedback of the inner shaft 3. The feedback data is given to the driver, and the driver then realizes the closed-loop feedback of the position of the inner shaft 3; after the driver energizes the direct-drive motor stator 2 13, it drives the direct-drive motor stator 2 14 to drive the outer shaft 12 to rotate, and the circular grating 2 16 is used as the position feedback of the outer shaft 12. The feedback data is given to the driver, and the driver then realizes the closed-loop feedback of the position of the outer shaft 12. In this complete signal feedback process, no other interruptions will occur, forming a complete closed-loop behavior.

[0032] 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 may be replaced by equivalents. However, 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. A dual-axis direct-drive goniometer for an X-ray diffractometer, characterized in that: It includes a shell and an inner shaft and an outer shaft rotatably matched with the shell, the inner shaft is located on the inner side of the outer shaft, a direct-drive motor mover 1 and a direct-drive motor mover 2 are rotatably connected in the shell, the direct-drive motor mover 1 and the direct-drive motor mover 2 are respectively fixedly connected to the inner shaft and the outer shaft, and a direct-drive motor stator 1 and a direct-drive motor stator 2 are also fixedly connected in the shell, the direct-drive motor stator 1 and the direct-drive motor stator 2 can respectively drive the direct-drive motor mover 1 to drive the inner shaft and the direct-drive motor mover 2 to drive the outer shaft to rotate with their axes as rotating axes.

2. A dual-axis direct-drive goniometer for an X-ray diffractometer according to claim 1, characterized in that: The inner shaft is coaxial with the outer shaft axis, and a gap is left between the inner wall of the outer shaft and the outer wall of the inner shaft.

3. The dual-axis direct-drive goniometer for an X-ray diffractometer according to claim 1, characterized in that: The housing comprises a housing 1 and a housing 2 which are fixedly connected, the inner shaft is rotatably connected to the housing 2, and the outer shaft is rotatably connected to the housing 1.

4. The dual-axis direct-drive goniometer for an X-ray diffractometer according to claim 1, characterized in that: The inner shaft and the outer shaft are both rotatably connected to the housing via bearings, the two inner rings of the bearings are fixedly connected to the inner shaft and the outer shaft respectively, and the two outer rings of the bearings are fixedly connected to the housing.

5. The dual-axis direct-drive goniometer for an X-ray diffractometer according to claim 1, characterized in that: A circular grating and a limit block are arranged at one end of the inner shaft. The circular grating is coaxial with the axis of the inner shaft. The end face of the inner shaft is provided with a limit block. The inner wall of the shell is provided with a limit baffle matched with the limit block.

6. A dual-axis direct-drive goniometer for an X-ray diffractometer according to claim 1, characterized in that: One end of the outer shaft is provided with a second circular grating and a limit block, the second circular grating is fixedly connected to one end of the outer shaft, the end face of the outer shaft is fixedly connected with another limit block, and the inner wall of the shell is provided with a limit baffle matched with the limit block.

7. A dual-axis direct-drive goniometer for an X-ray diffractometer according to claim 3, characterized in that: The inner shaft is rotatably connected to the second shell, and the outer shaft is rotatably connected to the first shell.

8. The dual-axis direct-drive goniometer for an X-ray diffractometer according to claim 1, characterized in that: The inner shaft passes through the inner hole of the outer shaft and is connected to an external device, wherein the external device includes an optical machine or a detector or a test sample.

9. The dual-axis direct-drive goniometer for an X-ray diffractometer according to claim 5, characterized in that: The circular grating 1 is electrically connected to the stator 1 of the direct drive motor.

10. The dual-axis direct-drive goniometer for an X-ray diffractometer according to claim 6, characterized in that: The second circular grating is electrically connected to the second stator of the direct drive motor.

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