CN102158007B - Electromechanical driver - Google Patents

Abstract

An electromechanical driver is composed of a differential screw pair structure, a friction wheel structure, and a pressing device. The motor drives the differential screw pair structure through the friction wheel structure to convert rotational motion into linear motion; the screw transmission structure adopts a differential screw pair The structure improves the precision of the screw transmission structure; the friction wheel structure avoids the axial movement of the power components such as the motor through the driven wheel of the spiral motion, and improves the stability of the system; the compression device uses the compression spring to provide friction wheel structure The required pressing force ensures the normal operation of the friction wheel structure. In the active optical system, the present invention is fixed in the mirror chamber, and through force sensors, flexible connectors, etc., the tension and pressure force is applied to the optical mirror surface, and the control system is based on the difference between the force measurement value of the force sensor and the force required by the active optical system. Adjust the amount of movement of the motor until it meets the requirements of the optical mirror surface shape. The invention has the advantages of convenient processing, maintenance and replacement, and reliable and stable performance.

Description

An electromechanical drive

technical field

The invention relates to an electromechanical driver for applying tension and compression bidirectional force along the axial direction of an optical mirror in a dynamic optical system, which belongs to a mechanical device.

Background technique

In the large-aperture telescope systems at home and abroad, the primary mirror system adopts a dynamic optical system, which uses the driver array installed on the back of the active thin primary mirror to change the shape of the primary mirror, and then realizes the correction of the wavefront error, so that the telescope optical system maintains a good optical system. wavefront quality. In the active thin primary mirror optical system, the driver is mainly used to bear the weight of the active primary mirror and correct the surface shape of the primary mirror. Therefore, the driver is required to have the characteristics of large stroke, strong load, high precision, and stable movement. Large-aperture telescope systems at home and abroad generally use The driver device is realized by hydraulic, pneumatic or mechanical structure. At the same time, during the working process, the force sensor is used to measure the output force of the driver, and the measured value is sent to the control system. For example, Figure 1 shows the driver in NTT, which adopts a mechanical structure. It uses a fixed counterweight to bear the weight of the mirror, and uses a stepping motor to move the free counterweight through a ball screw. The lever structure is used to correct the surface shape. Providing varying forces, the drive has a small load capacity and can only provide one-way pressure loads. Figure 2 shows the drive structure designed by VLT. It consists of two parts, the active structure and the passive structure. The active structure is a mechanical structure. The motor drives the ball screw and the elastic element to generate a changing force. This part of the force is mainly used to correct the mirror surface. The surface shape and the passive structure are hydraulic structures, which are mainly used to bear the weight of the primary mirror. The driver has a large load and high precision, but it is bulky and inconvenient to install and maintain. Figure 3 describes the driver structure of the SUBARU telescope, which also adopts a mechanical driver structure. The contact point between the driver and the mirror is located on the center of gravity of the primary mirror, and the counterweight is used to bear the axial and radial weight of the primary mirror to correct the surface shape. The force is provided by the motor through the lead screw to push the spring. The driver has high precision, large stroke and smooth movement, but the structure is also huge and expensive. As shown in Figure 4, the driver of the LAMOST telescope adopts the structure of motor-driven ball screw and elastic element, which belongs to the mechanical structure. The structure shown in Figure 5 is a pneumatic actuator mentioned in the domestic patent "A Pneumatic Force Actuator" (Yao Zhengqiu, Wang Yuefei, Cui Xiangqun, Patent No. ZL97236305. It is called a driver), which uses a motor to drive a bellows with airtight sealing through a ball screw, so as to apply a bidirectional force to the active optical mirror. Due to the existence of the ball screw, the drive cannot be self-locked, and a locking device is required.

As an extremely important mechanical transmission structure with mature and stable technology, screw transmission plays an important role in the fields of micro-displacement drive and positioning, precision and ultra-precision machining, etc., especially the application of differential screw structure improves the accuracy of screw transmission , the differential helical structure consists of two thread pairs with the same direction of rotation and different pitches. The equivalent pitch is the difference between the pitches of the two thread pairs. The general differential helical structure includes three parts: a fixed nut, a translation nut and a differential screw. Due to the helical motion of the differential screw, the motor and other power components cannot be directly connected to it to ensure the stability of the motor and other power components. Other mechanical devices capable of producing high-precision displacement include electrostrictive, magnetostrictive, and elastic deformation structures. They generally have high stiffness and good dynamic characteristics, but have a small stroke and low load capacity.

Contents of the invention

The invention technically solves the problem: overcomes the deficiencies of the prior art, and provides an electromechanical driver, which uses basic transmission structures such as a differential spiral structure and a friction wheel structure, and is easy to process, maintain and replace, and has reliable and stable performance.

The technical solution of the present invention is: the electromechanical driver includes: motor 8, differential screw pair structure 23, friction wheel structure 17, pressing device 10 and reduction box 9; The wheel structure 17 is connected, the friction wheel structure 17 is installed in the pressing device 10, and is connected with the differential screw pair structure 23, and the pressing device 10 and the differential screw pair structure 23 are both fixed on the bottom plate 28;

Described friction wheel structure 17 comprises driving wheel shaft 14, driving wheel 18, driven wheel 19, two ball bearings 21 and ball bearing fixed shaft 20; The wheel shaft 14 rotates, and the driving wheel 18 is in circumscribed contact with the driven wheel 19; the driven wheel 19 is axially connected with the differential screw shaft 24 of the differential screw substructure 23; The two sides are symmetrically distributed, and the inner rings of the two ball bearings 21 are respectively fixed on the two fixed shafts 20 of the ball bearings. touch;

Described pressing device 10 comprises compression spring 11, connecting shaft 12, swivel frame 13, rotary shaft 15, driving wheel fixed mount 16, driven wheel fixed mount 22; Driving wheel 18 is installed in rotating frame 13 by driving wheel shaft 14, rotates The frame 13 is installed on the driving wheel fixed frame 16 via the rotary shaft 15, the rotary frame 13 is connected with the connecting shaft 12 via the compression spring 11, the ball bearing fixed shaft 20 is fixed in the driven wheel fixed frame 22, the rotary frame 13 and the driven wheel fixed frame 22 are connected by connecting shaft 12.

The differential screw pair structure 23 includes a differential screw shaft 24, a sleeve fixing plate 25, a sleeve 26 and an output shaft 27; the differential screw shaft 24 forms a screw pair with the sleeve 26 and the output shaft 27 respectively, and the differential screw shaft The shaft 24 is connected to the driven wheel 19 in the axial direction, and the sleeve 26 is fixedly connected to the bottom plate 28 via the sleeve fixing plate 25 .

In the working process of the present invention, the motor first drives the friction wheel structure through the reduction box and the shaft coupling. The friction wheel structure in the present invention is a parallel friction wheel structure, and the same point as the traditional parallel friction wheel structure is that the driving wheels all rotate The difference is that the driven wheel does not rotate but does spiral motion. The friction wheel structure also includes two ball bearings that are in circumscribed contact with the driven wheel and rotate. The friction wheel structure is controlled by the compression device by adjusting the compression spring. The amount of deformation makes the rotating frame rotate around the rotating shaft to provide the required pressing force; then the driven wheel drives the differential screw pair structure to move, and the differential screw pair structure in the present invention is mainly composed of a sleeve, an output shaft and a differential The screw is composed of three parts, the differential screw and the sleeve and the output shaft form a screw pair respectively, the sleeve is fixed on the bottom plate, the differential screw is coaxially connected with the driven wheel, and the output shaft is equivalent to the translation nut in the traditional differential screw structure ; and then the differential screw converts the helical motion of the driven wheel to the output shaft as a linear motion output; finally, the force sensor connected to the output shaft applies the force to the mirror, and the control system is based on the force measured by the force sensor and the active optical system. The difference in the required force is used to adjust the amount of movement of the motor until it meets the requirements of the mirror surface shape. The application of the differential screw pair structure improves the precision of the screw transmission structure; the existence of the friction wheel structure avoids the axial movement of the driving parts such as the motor, and improves the stability of the system; the compression device mainly uses the compression spring as the friction wheel structure The required pressing force is provided to ensure the normal operation of the friction wheel structure.

The working principle of the present invention is: the motor drives the friction wheel structure and the differential screw pair structure through the reduction box and the coupling, the pressing device provides the required pressing force for the friction wheel structure, and the friction wheel structure converts the rotational motion of the motor It is the output of spiral motion, and then the differential spiral substructure converts the input spiral motion into linear motion output, and finally the force sensor applies the force to the mirror surface, and the control system is based on the force measured by the force sensor and the force required by the active optical system Adjust the amount of movement of the motor until it meets the requirements of the mirror surface shape.

The friction wheel structure in the present invention is composed of a driving wheel, a driven wheel and two ball bearings. The driving wheel rotates under the drive of the motor, and the driven wheel performs a spiral motion. The inner ring of the ball bearing is fixed on the fixed shaft of the ball bearing, and the outer ring and the The driven wheel is in contact with the rotary motion, and the driven wheel is coaxially connected with the differential screw pair structure. The use of the friction wheel structure avoids the axial movement of the power such as the motor, and improves the stability of the system.

The pressing device in the present invention is mainly composed of a compression spring, a rotating frame, a driving wheel fixing frame, a driven wheel fixing frame, etc., the driving wheel is installed on the rotating frame, the rotating frame can rotate around the driving wheel fixing frame, and the ball bearing is installed on the driven wheel The fixed frame, the driving wheel fixed frame, and the driven wheel fixed frame are all fixed on the base plate, and the compression spring is used to make the rotating frame rotate to the driven wheel fixed frame, thereby providing sufficient pressing force for the friction wheel structure.

Compared with the prior art, the present invention has the beneficial effects that: the present invention is simple in structure and principle, good in manufacturability, not only can meet the technical requirements of the optical mirror in the active optical system for the driver, but also has relatively high precision, convenient processing and maintenance, and can A bidirectional force of tension and compression is applied along the axis of the optical mirror.

Description of drawings

Fig. 1 is the schematic diagram of the driver structure in the NTT telescope;

Fig. 2 is the schematic diagram of the driver structure in the VLT telescope;

Fig. 3 is a schematic diagram of the driver structure in the SUBARU telescope;

Figure 4 is a schematic diagram of the driver structure in the LAMOST telescope;

Figure 5 is a structural schematic diagram of the driver designed by the patent ZL97236305.X;

Fig. 6 is a schematic diagram of the installation structure of a screw drive driver in the active optical system of the present invention;

Fig. 7 is a schematic diagram of the internal structure of a screw drive driver of the present invention;

Fig. 8 is a schematic structural diagram of the friction wheel in Fig. 7;

Fig. 9 is a schematic structural view of the pressing device in Fig. 7, Fig. 9a is a schematic structural view of the driving wheel of the pressing device, and Fig. 9b is a schematic structural view of the driven wheel of the pressing device;

FIG. 10 is a schematic diagram of the structure of the differential helical pair in FIG. 7 .

In the above-mentioned figures 6-10, 1 mirror surface, 2 coupling parts, 3 upper flexible parts, 4 force sensors, 5 lower flexible parts, 6 mirror chambers, 7 drivers, 8 motors, 9 reduction boxes, 10 pressing devices, 11 compression Spring, 12 connecting shaft, 13 rotating frame, 14 driving wheel shaft, 15 rotating shaft, 16 driving wheel fixing frame, 17 friction wheel structure, 18 driving wheel, 19 driven wheel, 20 ball bearing fixed shaft, 21 ball bearing, 22 driven wheel Fixed frame, 23 differential screw substructure, 24 differential screw rod, 25 sleeve fixed frame, 26 sleeve, 27 output shaft, 28 bottom plate, 29 reduction box fixed plate, 30 coupling, 31 control system.

Detailed ways

As shown in Fig. 6-Fig. 10, the structure of the present invention is:

Figure 6 describes the installation structure of the driver 7 in the active optical system. The sleeve 26 of the driver 7 is fixed to the mirror chamber 6, and its output shaft 27 passes through the lower flexible part 5, the force sensor 4, the upper flexible part 3, and the connecting part in turn. 2 is attached to mirror 1.

Fig. 7 has described the internal structure of driver 7, and motor 8 is connected with friction wheel structure 17 via reduction box 9, coupling 30, and friction wheel structure 17 is installed in pressing device 10, and is connected with differential screw pair structure 23, Both the pressing device 10 and the differential screw substructure 23 are fixedly connected to the bottom plate 28 .

Fig. 8 has described friction wheel structure 17, and it is made up of driving wheel 18, driving wheel shaft 14, driven wheel 19, two ball bearings 21, ball bearing fixed shaft 20, driving wheel shaft 14 links to each other with reduction box 9 via shaft coupling 30, The driving wheel 18 rotates around the driving wheel shaft 14, and the driving wheel 18 is in circumscribed contact with the driven wheel 19; the driven wheel 19 is axially connected with the differential screw shaft 24 of the differential screw substructure 23; the inner ring of the ball bearing 21 is fixed on the ball bearing The shaft 20 is fixed, and the outer ring of the ball bearing 21 is in circumscribed contact with the driven wheel 19 . The driving wheel 18 rotates under the drive of the motor 8, the driven wheel 19 performs a spiral motion, the inner ring of the ball bearing 21 is fixed on the fixed shaft 20 of the ball bearing, the outer ring contacts the driven wheel 19 to perform a rotating motion, the driven wheel 19 and the differential screw The auxiliary structure is coaxially connected, and the use of the friction wheel structure avoids the axial movement of the motor and other power, and improves the stability of the system.

Fig. 9 has described holding down device structure 10, and it is made up of compression spring 11, connecting shaft 12, swivel frame 13, rotating shaft 15, driving wheel fixing frame 16, driven wheel fixing frame 22, and Fig. 9 a is the driving force of holding down device 10 The structure of the wheel part, the driving wheel 18 is installed in the rotating frame 13 through the driving wheel shaft 14, the rotating frame 13 is installed in the driving wheel fixed frame 16 through the rotating shaft 15, and the rotating frame 13 is connected with the connecting shaft 12 through the compression spring 11. The driven wheel part structure of the tightening device 10, the ball bearing fixed shaft 20 is fixedly connected in the driven wheel fixed frame 22, and the rotating frame 13 is connected with the driven wheel fixed frame 22 through the connecting shaft 12.

Fig. 10 has described differential screw pair structure 23, and it is made up of differential screw shaft 24, sleeve fixing plate 25, sleeve 26, output shaft 27, and differential screw shaft 24 forms spiral with sleeve 26, output shaft 27 respectively Auxiliary, the differential screw shaft 24 is axially connected with the driven wheel 19, the flange end of the sleeve 26 is fixed to the mirror chamber 6, the other end is fixed to the bottom plate 28 through the sleeve fixing plate 25, the output shaft 27 is connected to the lower flexible part 5 connected.

The working process of the present invention: the motor 8 first drives the friction wheel structure 17 through the reduction box 9 and the shaft coupling 30. The friction wheel structure 17 in the present invention is a parallel friction wheel structure, and the same point as the traditional parallel friction wheel structure is active The wheels 18 all perform rotational motion, and the difference is that the driven wheel 19 does not perform rotational motion but a spiral motion. The friction wheel structure 17 also includes two ball bearings 21 that are in circumscribed contact with the driven wheel 19 and perform rotational motion. The friction wheel structure 17. The pressing device 10 adjusts the deformation of the compression spring 11 to make the swivel frame 13 rotate around the rotating shaft 15 to provide the required pressing force; then the driven wheel 19 drives the differential screw pair structure 23 to move. The differential screw pair structure 23 is mainly composed of three parts: a sleeve 26, an output shaft 27 and a differential screw 24. The differential screw 24 forms a screw pair with the sleeve 26 and the output shaft 27 respectively, and the sleeve 26 is fixed on the bottom plate 28. , the differential screw 24 is coaxially connected with the driven wheel 19, and the output shaft 27 is equivalent to a translation nut in a traditional differential screw structure; and then the differential screw 24 converts the spiral motion of the driven wheel 19 into a linear motion output Finally, the force sensor 4 that is connected to the output shaft 27 applies the force to the mirror surface 1, and the control system 31 in the active optics technology controls the motor 8 according to the difference between the force sensor 4 and the force required by the active optical system. The amount of movement is adjusted until the requirements of the mirror surface 1 surface shape are met.

Claims (2)

1. an electromechanical driver is characterized in that comprising: motor (8), differential screw auxiliary structure (23), structure of friction wheel (17), hold down gag (10) and reduction box (9); Motor (8) links to each other with structure of friction wheel (17) via reduction box (9), coupling (30), structure of friction wheel (17) is installed in the hold down gag (10), and be connected with differential screw auxiliary structure (23), hold down gag (10) all is fixed in base plate (28) with differential screw auxiliary structure (23);

Described structure of friction wheel (17) comprises drive sprocket axle (14), driving wheel (18), driven pulley (19), two ball bearings (21) and ball bearing fixed axis (20); Drive sprocket axle (14) links to each other with reduction box (9) via coupling (30), and driving wheel (18) is around drive sprocket axle (14) rotation, driving wheel (18) and circumscribed contact of driven pulley (19); Driven pulley (19) axially is connected with the differential screw axle (24) of differential thread auxiliary structure (23); The both sides that two ball bearings (21) are positioned at plane, high place, driven pulley (19) center are symmetrically distributed, two ball bearings (21) inner ring is individually fixed in two ball bearing fixed axis (20), ball bearing fixed axis (20) is all installed with driven pulley (19) axially parallel, ball bearing (21) outer ring and circumscribed contact of driven pulley (19);

Described hold down gag (10) comprises Compress Spring (11), connecting axle (12), swivel mount (13), rotating shaft (15), driving wheel fixed mount (16), driven pulley fixed mount (22); Driving wheel (18) is installed in the swivel mount (13) by drive sprocket axle (14), swivel mount (13) is installed on driving wheel fixed mount (16) via rotating shaft (15), swivel mount (13) is connected with connecting axle (12) via Compress Spring (11), ball bearing fixed axis (20) is fixed in the driven pulley fixed mount (22), and swivel mount (13) is connected by connecting axle (12) with driven pulley fixed mount (22);

Described differential screw auxiliary structure (23) comprises differential screw axle (24), sleeve fixed head (25), sleeve (26) and output shaft (27); Differential screw axle (24) forms screw pair with sleeve (26) and output shaft (27) respectively, and differential screw axle (24) is connected with driven pulley (19) vertically, and sleeve (26) is fixedly connected on base plate (28) via sleeve fixed head (25).

2. electromechanical driver according to claim 1, it is characterized in that: sleeve (26) flange end in the described differential screw auxiliary structure (23) is fixed in the mirror cell (6) in the active optics system, and output shaft (27) links to each other with lower end flexible connecting member (5) in the active optics system.

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