A high-precision space camera focusing mechanism using flexible connection

Abstract

The invention discloses a high-precision space camera focusing mechanism using flexible connection, comprising a bearing seat (1), a nut (2), a ball screw (3), a base (4), a bearing 1 (5), a motor (6), a worm seat (7), a worm (8), a worm wheel pressure ring (9), an encoder (10), a worm wheel (11), a workbench (12), a cylindrical pin (13), a screw (14), a ball head screw (15), a bearing 2 (16), a flexible plate (17), a guide rail (18) and a lower connecting plate (19); the focusing mechanism uses a motor as a driving unit and an encoder as a feedback unit, and converts rotary motion into linear motion through worm gear, ball screw and nut transmission, and realizes precise guidance through the guide rail. The invention releases part of the degree of freedom through a flexible plate structure, solves the interference problem in the assembly and movement process of the mechanism, greatly improves the assembly efficiency, assembly accuracy and accuracy stability of the focusing mechanism, and the invention has a simple structure, good rigidity, convenient operation and a wide range of applications.

Description

Technical Field

[0001] The invention belongs to the field of aerospace technology, and in particular relates to a high-precision space camera focusing mechanism using a flexible connection. Background Art

[0002] The focusing scheme using stepper motor drive, worm gear reduction self-locking, lead screw nut transmission and guide rail guidance is the most widely used and traditional scheme in the field of aerospace technology. In this scheme, the connection between the nut and the workbench is over-positioned and difficult to assemble. There are three commonly used connection structures on the ground: (1) ball head; (2) pin; (3) screw. In order to resist the complex mechanical environment in space, the two ends of the lead screw shaft are fixed and constrained by bearings. The rigidity of the lead screw is very high. When the rigidity of the workbench is weaker than that of the lead screw shaft, there will inevitably be interference when the screw connection method is used. This interference will cause the workbench to deform, and then the straightness of the mechanism will deteriorate. The straightness has a great influence on the optical path transmission. In addition, if the interference is large, the contact state will change after the complex mechanical environment test, and the accuracy stability will be poor. The ball head structure has yielding in all three directions, which improves the assembly efficiency and accuracy stability, but the backlash is large, which will affect the positioning accuracy of the mechanism in the linear motion direction. The pin connection releases the degree of freedom in the up and down directions, but there is a gap in the linear motion direction, which will also affect the positioning accuracy of the mechanism.

[0003] In order to ensure both high positioning accuracy and precision stability of the mechanism, the present invention proposes a focusing mechanism using a flexible connection. The flexible connection structure is partially flexible in the up and down directions (i.e., the Z direction in the attached figure), and has sufficient strength and rigidity in the remaining directions. The flexibility in the upper and lower directions can accommodate the interference amount of the mechanism during movement, and the high rigidity in the remaining directions ensures the movement accuracy of the mechanism. The flexible structure is easy to dismantle and will not affect the accuracy of the shaft system. When the rigidity of the flexible plate is insufficient, the rigidity value can be adjusted by adding vacuum glue to achieve the best positioning accuracy. This structure greatly improves the assembly efficiency of the mechanism, ensuring accuracy while also ensuring the stability of accuracy. Summary of the invention

[0004] The technical problem to be solved by the present invention is: in the field of aerospace technology, the focusing scheme of space cameras has many applications, long service life, high precision and high reliability, which is driven by a stepper motor, self-locking worm gear reduction, screw nut transmission, and guide rail guidance. The difficulty of this scheme is the over-positioning of the connection between the screw nut and the workbench. When the rigidity of the screw shaft of the mechanism is high and the rigidity of the workbench is relatively weak, the structure of the connection part has a significant impact on the accuracy. In order to make up for the shortcomings of the existing structure, a precision-adjustable focusing mechanism is proposed, which greatly improves the assembly efficiency.

[0005] To solve the above technical problems, the present invention is implemented through the following solutions:

[0006] A high-precision space camera focusing mechanism using flexible connection includes a bearing seat 1, a nut 2, a ball screw 3, a base 4, a bearing 1 5, a motor 6, a worm seat 7, a worm 8, a worm wheel pressure ring 9, an encoder 10, a worm wheel 11, a workbench 12, a cylindrical pin 13, a screw 14, a ball head screw 15, a bearing 2 16, a flexible plate 17, a guide rail 18 and a lower connecting plate 19. Two guide rails 18 are installed on the base 4 to ensure that the parallelism of the two guide rails 18 is within a suitable range; the ball screw 3 and the nut 2 are installed in the bearing holes of the base 4 and the bearing seat 1, and are supported by the bearing 1 5 and the bearing 2 16 to ensure that the parallelism of the axis of the ball screw 3 and the guide rail is within a suitable range; the workbench 12 is installed on the guide rail 18 and is connected to the nut 2 through the flexible plate 17 and the lower connecting plate 19; the worm wheel 11 is installed On the shaft of the ball screw 3, and tightened with a worm gear pressure ring 9; the worm seat 7 is installed on the base 4 by means of screws 14, and is pinned to position, and the cylindrical pin 13 penetrates the workbench 12 and the flexible plate 17 by matching to prevent relative tangential displacement between the joint surfaces; the stator, motor 6, and worm 8 of the encoder 10 are installed on the worm seat 7, and the worm 8 axis and the ball screw 3 axis are orthogonal in space. The motor 6 is coaxial with the worm 8 and is connected through a coupling. The encoder 10 consists of two coaxial parts, a stator and a rotor, wherein the rotor is installed on the end of the ball screw 3 axis, and the stator is installed on the worm seat 7. The stator and the rotor are both coaxial with the screw 3. The two ends of the worm 8 are supported by bearings 1 5 and 16. The ball head top screw 15 is installed on the workbench 12, screwed into the threaded through hole and rests on the end face of the nut 2.

[0007] Furthermore, a flexible groove is cut on the flexible plate 17 to ensure that the flexible plate 17 has sufficient strength and rigidity in the X and Y directions, and has appropriate flexibility in the Z direction, so as to accommodate the position error of the mechanism that changes continuously during the movement process, ensure that the rotation angle of the ball screw is effectively converted into linear motion, and ensure that the mechanism has high positioning accuracy and repeatability.

[0008] Furthermore, when the rigidity and strength of the flexible board 17 cannot meet the use requirements, low-volatile vacuum glue is used to fill the flexible groove to achieve micro-adjustment of the flexible structure and find the optimal rigidity state of the flexible board 17;

[0009] Furthermore, the connection component between the nut 2 and the workbench 12 is made of two independent parts, namely the flexible plate 17 and the lower connecting plate 19, which facilitates the installation and commissioning of the flexible plate 17 without disassembling the shaft system;

[0010] Furthermore, the ball head screw 15 limits the freedom of the mechanism in the linear motion direction (ie, the x direction in the figure), ensuring that the mechanism has sufficient load-bearing capacity in the linear motion direction.

[0011] Furthermore, the flexible plate 17 structure releases some degrees of freedom, solves the interference problem during the assembly and movement of the mechanism, and greatly improves the assembly efficiency, assembly accuracy and accuracy stability of the focusing mechanism. The present invention has a simple structure, good rigidity, easy operation and a wide range of applications.

[0012] Compared with the existing space camera focusing mechanism, the present invention has the following advantages:

[0013] 1. The present invention releases some degrees of freedom through the flexible plate, solves the interference problem during the assembly and movement of the mechanism, and greatly improves the assembly efficiency and assembly accuracy of the focusing mechanism;

[0014] 2. In the present invention, the flexible plate is easy to disassemble without removing the shaft system. When the rigidity of the flexible plate is insufficient, a slight adjustment can be made by adding vacuum glue in the flexible groove, which greatly saves processing and adjustment time and reduces production costs.

[0015] 3. In the present invention, the ball head screw 15 limits the freedom of the mechanism in the direction of linear motion, ensuring that the mechanism has sufficient load-bearing capacity in the direction of linear motion, and sputters MoS2 at the contact portion between the workbench 12 and the nut 2 to prevent vacuum cold welding. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a front view of a high-precision space camera focusing mechanism using a flexible connection according to the present invention;

[0017] Figure 2 It is a MM cross-sectional view of the present invention;

[0018] Figure 3 is an appearance diagram of the present invention;

[0019] Figure 4 It is a top view of the present invention.

[0020] The numbers in the figure represent: 1. bearing seat; 2. nut; 3. ball screw; 4. base; 5. bearing one; 6. motor; 7. worm seat; 8. worm; 9. worm gear pressure ring; 10. encoder; 11. worm gear; 12. workbench; 13. cylindrical pin; 14. screw; 15. ball head screw; 16. bearing two; 17. flexible board; 18. guide rail; 19. lower connecting plate. DETAILED DESCRIPTION

[0021] The present invention is further described below with reference to the accompanying drawings and specific embodiments.

[0022] like Figures 1 to 4As shown, a high-precision space camera focusing mechanism using flexible connection includes a bearing seat 1, a nut 2, a ball screw 3, a base 4, a bearing 1 5, a motor 6, a worm seat 7, a worm 8, a worm wheel pressure ring 9, an encoder 10, a worm wheel 11, a workbench 12, a cylindrical pin 13, a screw 14, a ball head screw 15, a bearing 2 16, a flexible plate 17, a guide rail 18 and a lower connecting plate 19; wherein: the high-precision space camera focusing mechanism using flexible connection uses the motor 6 as a driving unit and the encoder 10 as a feedback unit, and converts the rotational motion into the linear motion through the worm wheel 11, the worm 8, the ball screw 3, and the nut 2, and realizes precise guidance through the guide rail 18;

[0023] Two guide rails 18 are installed on the base 4 to ensure that the parallelism of the two guide rails 18 is within an appropriate range; the ball screw 3 and the nut 2 are installed in the bearing holes of the base 4 and the bearing seat 1, and are supported by the bearing 1 5 and the bearing 2 16. It is necessary to ensure that the parallelism of the ball screw 3 axis and the guide rail is within an appropriate range; the workbench 12 is installed on the guide rail 18 and connected to the nut 2 through the flexible plate 17 and the lower connecting plate 19; the worm wheel 11 is installed on the shaft of the ball screw 3 and is pressed with the worm wheel pressure ring 9; the worm seat 7 is installed on the base 4 by the screw 14, and is pinned to position, and the round The pin 13 penetrates the workbench 12 and the flexible plate 17 by matching to prevent relative tangential displacement between the joint surfaces; the stator, motor 6, and worm 8 of the encoder 10 are installed on the worm seat 7, the worm 8 axis and the ball screw 3 axis are orthogonal in space, the motor 6 is coaxial with the worm 8 and connected through a coupling, and the encoder 10 is composed of two coaxial parts of the stator and rotor, wherein the rotor is installed on the end of the ball screw 3 axis, the stator is installed on the worm seat 7, the stator and the rotor are coaxial with the screw 3, and the two ends of the worm 8 are supported by bearing 1 5 and bearing 2 16. The ball head screw 15 is installed on the workbench 12, screwed into the threaded through hole and pressed against the end face of the nut 2.

[0024] The flexible plate 17 is cut with a flexible groove to ensure that the flexible plate 17 has sufficient strength and rigidity in the X and Y directions, and has appropriate flexibility in the Z direction, so as to accommodate the position error of the mechanism that changes constantly during the movement, ensure that the rotation angle of the ball screw is effectively converted into linear motion, and ensure that the mechanism has high positioning accuracy and repeat positioning accuracy; when the rigidity of the flexible plate 17 is insufficient, it is reinforced with low-volatile vacuum glue, and the optimal rigidity state of the flexible plate 17 is found according to the actual installation and adjustment conditions; the connecting component between the nut 2 and the workbench 12 adopts two independent parts, the flexible plate 17 and the lower connecting plate 19, which is convenient for the installation and debugging of the flexible plate 17 without disassembling the shaft system; the ball head screw 15 limits the freedom of the mechanism in the linear motion direction (i.e., the x direction in the attached figure), ensuring that the mechanism has sufficient bearing capacity in the linear motion direction. The present invention releases part of the freedom through the structure of the flexible plate 17, solves the interference problem in the assembly and movement of the mechanism, greatly improves the assembly efficiency, assembly accuracy and stability of the precision of the focusing mechanism, and the present invention has a simple structure, good rigidity, convenient operation and a wide range of applications.

[0025] Due to errors in processing and assembly, the stiffness and strength of the flexible board 17 are also different from the theoretical data. When the stiffness and strength of the flexible board 17 cannot meet the use requirements, low-volatile vacuum glue is used to fill the flexible groove to achieve slight adjustments to the flexible structure and find the optimal stiffness state of the flexible board 17, which greatly saves processing and assembly time and reduces production costs.

[0026] The parts not described in detail in the present invention belong to the well-known technology in the art.

[0027] The above descriptions are only some specific implementation methods of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by any person familiar with the art within the technical scope disclosed in the present invention should be covered within the protection scope of the present invention.

Claims

1. A high-precision space camera focusing mechanism using a flexible connection, characterized in that: It includes a bearing seat (1), a nut (2), a ball screw (3), a base (4), a bearing 1 (5), a motor (6), a worm seat (7), a worm (8), a worm wheel pressure ring (9), an encoder (10), a worm wheel (11), a workbench (12), a cylindrical pin (13), a screw (14), a ball head screw (15), a bearing 2 (16), a flexible plate (17), a guide rail (18) and a lower connecting plate (19), wherein the two guide rails (18) are installed on the base (4) The ball screw (3) and the nut (2) are installed in the bearing holes of the base (4) and the bearing seat (1), and supported by the first bearing (5) and the second bearing (16), so as to ensure that the parallelism of the ball screw (3) axis and the guide rail (18) is within a suitable range; the workbench (12) is installed on the guide rail (18) and connected to the nut (2) through the flexible plate (17) and the lower connecting plate (19); the worm gear (11) is installed On the shaft of the ball screw (3), and tightened with a worm wheel pressure ring (9); the worm seat (7) is installed on the side of the base (4) by means of screws (14) and is pinned for positioning; the cylindrical pin (13) penetrates the workbench (12) and the flexible plate (17) by means of matching, so as to prevent tangential relative displacement between the joint surfaces; the encoder (10) stator, the motor (6), and the worm (8) are installed on the worm seat (7), and the worm (8) and the ball screw (3) axis are arranged orthogonally in space The motor (6) is coaxial with the worm (8) and connected through a coupling. The encoder (10) is composed of two coaxial parts, a stator and a rotor, wherein the rotor is mounted on the shaft end of the ball screw (3), and the stator is mounted on the worm seat (7). Both the stator and the rotor are coaxial with the ball screw (3). The two ends of the worm (8) are supported by bearing 1 (5) and bearing 2 (16). The ball head screw (15) is mounted on the workbench (12), screwed into the threaded through hole and resting on the end face of the nut (2); The flexible plate (17) is cut with flexible grooves to ensure that the flexible plate (17) has sufficient strength and rigidity in the X and Y directions, and has appropriate flexibility in the Z direction, so as to accommodate the position error of the mechanism that changes continuously during the movement process, ensure that the rotation angle of the ball screw is effectively converted into linear motion, and ensure that the mechanism has high positioning accuracy and repeatability. Due to processing and assembly errors, the stiffness and strength of the flexible board (17) also differ from theoretical data. When the stiffness and strength of the flexible board (17) cannot meet the use requirements, low-volatile vacuum glue is used to fill the flexible groove to achieve micro-adjustment of the flexible structure and find the optimal stiffness state of the flexible board (17).

2. The high-precision space camera focusing mechanism using flexible connection according to claim 1, characterized in that: The connection component between the nut (2) and the workbench (12) is composed of two independent parts, namely the flexible plate (17) and the lower connecting plate (19), so that the installation and debugging of the flexible plate (17) is convenient without disassembling the shaft system.

3. The high-precision space camera focusing mechanism using flexible connection according to claim 1, characterized in that: The ball head screw (15) limits the degree of freedom of the mechanism in the direction of linear motion, thereby ensuring that the mechanism has sufficient load-bearing capacity in the direction of linear motion.

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