CN201000502Y - A Focusing Mechanism Using Cam Drive to Realize Focusing of TV Telescope - Google Patents

Abstract

The utility model relates to a focusing mechanism for realizing the focusing of a television telescope by means of a cam transmission, which belongs to a focusing mechanism of a large television telescope involved in the technical field of photoelectric measurement and control. The technical problem to be solved is to provide a focusing mechanism of the television telescope using a cam drive. The technical solutions to be solved include primary, secondary, and tertiary transmission gears, cams, cam grooves, driving nails, optical objective lens groups, and linear guide rails. When the motor rotates under control, the first, second and third stage gear transmission drives the cam to rotate, and the upper end of the nail is driven into the cam groove, and the lower end is fixedly connected with the mirror holder. When the cam rotates, the nail is driven to move in the cam groove, and the The rotation of the cam is converted into the linear motion of the optical objective lens group, thereby playing a role in adjusting the focus of the optical lens group. The focusing mechanism moves smoothly and has high focusing precision.

Description

A Focusing Mechanism Using Cam Drive to Realize Focusing of TV Telescope

1. Technical field

The utility model belongs to a focusing mechanism of a large-scale television telescope and belongs to the technical field of photoelectric measurement and control.

2. Background technology

With the rapid development of sensing, computer, measurement and control technologies, new requirements are constantly put forward for the overall performance indicators such as the operating distance and measurement accuracy of photoelectric observation equipment. The imaging quality of the TV telescope is an important factor affecting the operating distance and measurement accuracy of the system. factor. An optical system with excellent imaging can only get a clear image when the target image is within the focal depth range during work. The degree of automation in contemporary TV telescopes continues to increase, and the focusing system basically uses automatic control technology to realize the automatic focusing function. However, due to the large error of the focusing mechanism and the electronic control system, the performance of the TV telescope is seriously affected at the cost of image quality loss.

The TV telescope is a large-scale equipment for capturing, tracking and observing air targets such as airplanes. In the process of tracking and aiming, changes in the distance of the target, ambient temperature and other factors will cause the target image to deviate from the focal plane or defocus, making the image blurred. The focusing mechanism is a mechanism for compensating image motion, adjusting defocus, and improving image quality. Therefore, the focusing mechanism of a TV telescope is crucial to the overall performance of a TV telescope.

The closest prior art with the utility model is the focusing mechanism of the large-scale photoelectric telescope developed by Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, as shown in Figure 1, including collimating objective lens assembly, drive transmission system and detection GPS. Among them, the collimating objective lens assembly includes anti-rotation screw 1, linear guide rail 2, mirror base 3, optical objective lens group 4, and driving nail 5; the driving transmission system includes screw nut 6, backlash-removing nut 7, lead screw 8, two-stage transmission large Gear 9, three-stage transmission pinion 10, gear box 11, motor 12, motor gear 13, double-connected first-stage transmission large gear 14, double-connected two-stage transmission small gear 15, double-connected three-stage transmission large gear 18, one Stage transmission shaft 20, secondary transmission shaft 21, screw shaft 23; monitoring and positioning system includes potentiometer gear 16, potentiometer 17, double detection pinion 19.

The motor gear 13 that is contained on the motor 12 shafts is engaged with the first-stage transmission bull gear 14 in the duplex gear mounted on the first-stage transmission shaft 20, and drives the secondary transmission pinion 15 in the duplex gear to rotate; The stage transmission pinion 15 meshes with the secondary transmission bull gear 9 mounted on the secondary transmission shaft 21, and the rotation of the secondary transmission bull gear 9 drives the tertiary transmission pinion 10 mounted on the right end through the secondary transmission shaft 21 to rotate; The three-stage transmission pinion 10 meshes with the three-stage transmission bull gear 18 mounted on the screw shaft 22 and drives the detection pinion 19 in the duplex gear to rotate; The potentiometer gear 16 is meshed, and the angle of rotation of the double detection pinion 19 is measured by the potentiometer 17, which can determine the moving distance of the collimating objective lens group 4, realize the adjustment of the defocus displacement, and achieve the purpose of image motion compensation. The lead screw 8 mounted on the lead screw shaft 22 and the double detection pinion 19 mounted on the lead screw shaft 22 rotate synchronously, and the rotation of the lead screw 8 drives the screw nut 6 matched with it to move left and right on the lead screw 8 along its axis , the screw nut 6 is fixedly connected with the driving nail 5 with a screw 23, and the upper end of the driving nail 5 is inserted into the mirror holder 3 of the collimating objective lens group 4. When the screw nut 6 drives the driving nail 5 to move left and right, the driving nail 5 drives the mirror The seat 3 makes linear reciprocating motion along the linear guide rail 2, so as to achieve the purpose of focusing.

The main problem of this focusing mechanism is that every link in the collimating objective lens detection kinematic chain affects the accuracy of the collimating objective lens movement, such as the tooth meshing gap between the transmission gear and the lead screw pair, the nonlinearity of the potentiometer, etc. Factors such as errors, especially the gap between the screw and the screw nut are difficult to control, which leads to the inability of the electronic control system to accurately control the positioning of the collimation objective lens group. Often, the image motion compensation is not in place and the focus is not accurate, so that the imaging quality is significantly reduced. .

3. Contents of the invention

In order to overcome the defects of the existing technology, the purpose of this utility model is to make the collimating objective lens move accurately, improve the precision of focusing and positioning control, and improve the imaging quality. A new type of focusing mechanism for a television telescope is specially designed.

The technical problem to be solved by the utility model is to provide a focusing mechanism of a television telescope that adopts a cam drive. The technical solution for solving technical problems is shown in Figure 3, including motor gear 24, primary transmission gear 25, primary transmission shaft 26, secondary transmission pinion 27, secondary transmission bull gear 28, and tertiary transmission pinion 29 , secondary transmission shaft 30, tertiary transmission gear 31, retaining ring 32, set screw 33, spring sleeve 34, tertiary transmission shaft 35, bearing cover 36, bearing 37, box side cover 38, pre-tightening nut 39. Spring 40, ball 41, motor 42, gear box 43, cam 44, cam groove 45, bearing 46, bearing cover 47, bearing 48, driving nail 49, optical objective lens group 50, mirror base 51, linear guide rail 52 , Straight through groove 53, end face boss 54, end face groove 55.

A motor 42 is installed on the upper side of the gear box body 43, and the shaft of the motor 42 extends into the box body. The first-stage transmission shaft 26, the second-stage transmission shaft 30, and the third-stage transmission shaft are sequentially installed inside the gear box body 43 from top to bottom. Axle 35, the bearing 46 of the same specification is all housed on the right-hand end shaft head of these three axles, stretches in the shaft hole of gear case body 43, and the bearing 37 of the same specification is all housed on the left side shaft head, stretches into the gear case body In the shaft hole of side cover plate 38, the outside is sealed with identical bearing cover 36, and bearing cover 36 is fastened with screw. The motor gear 24 is installed on the shaft of the motor 42, and the two are fixedly connected; the motor gear 24 meshes with the primary transmission gear 25 mounted on the right end of the primary transmission shaft 26, and the secondary transmission gear mounted on the left end of the primary transmission shaft 26. Transmission pinion 27 meshes with the secondary transmission bull gear 28 on the left end of secondary transmission shaft 30; The meshing of the three-stage transmission bull gear 31; the boss 54 on the right end of the three-stage transmission bull gear 31 is engaged with the groove 55 at the left end of the cam 44; on the left side of the three-stage transmission bull gear 31 on the three-stage transmission shaft 35, from right to left Ball 41, retaining ring 32, spring 40, spring sleeve 34, and preload nut 39 are installed in sequence; 34 is sleeved on the third-stage transmission shaft 35 from the left side, the right end is pushed against the shaft shoulder, and the left end is in contact with the inner ring of the bearing 37; Tightening nut 39 is pre-tightened, and pre-tightening nut 39 is fixed with fastening screw 33; The left axle head of three-stage transmission shaft 35 is loaded onto bearing 37, stretches in the shaft hole of gear box body 43, and the outside is added with bearing cover; The cylindrical linear guide rail 52 of the straight objective lens assembly is fixedly connected on the gear box body 43 with screws, and a linear through groove 53 is provided on the linear guide rail 52 to ensure the moving space of the driving nail 49. The upper end of the driving nail 49 is equipped with a bearing 48 to extend Into the cam groove 45 of the cam 44, the lower end of the driving nail 49 passes through the linear through groove 53 on the linear guide rail 52, and is fixedly connected with the mirror base 51 with screws. Driven by it, the mirror base 51 moves back and forth along the cylindrical guide rail 52.

Description of the working principle: when the motor 42 rotates under control, the motor gear 24 mounted on the motor shaft drives the secondary transmission pinion 27 mounted on the primary transmission shaft 26 to rotate through the meshing with the primary transmission gear 25, The secondary transmission pinion 27 meshes with the secondary transmission bull gear 28 mounted on the secondary transmission shaft 30, and the rotation of the secondary transmission bull gear 28 drives the tertiary transmission pinion 29 mounted on the secondary transmission shaft 30 to rotate, The tertiary transmission pinion 29 meshes with the tertiary transmission bull gear 31 mounted on the tertiary transmission shaft 35, and the rotation of the tertiary transmission bull gear 31 is through the meshing of the boss 54 on the bull gear 31 and the groove 55 on the cam 44 , to drive the cam 44 mounted on the right half of the third-stage transmission shaft 35 to rotate. Under normal working conditions, the cam 44 and the three-stage transmission gear 31 mesh together under the spring force, and the cam and the gear rotate synchronously. As long as it reaches the mechanical limit position, the spring 40 is deformed under pressure, and the cam 44 and the three-stage transmission gear 31 will slip between the connecting end faces, thereby protecting the mechanical parts such as the motor and the gear from being damaged; after the load returns to normal, the gear and the cam will Normal meshing work; the upper end of the driving nail 49 stretches into the cam groove 45, the lower end of the driving nail 49 is fixedly connected with the mirror holder 51, and the driving nail 49 converts the rotation of the cam 44 into the linear movement of the mirror holder 51 along the linear guide rail 52, thereby To achieve the focusing effect on the optical lens group.

The positive effects of the utility model: the present invention adopts the cam-driven nail mechanism as the linear motion and rotation conversion mechanism, because the cam groove is located on the outer surface of the cylinder, which reduces the processing difficulty and makes the cam groove easy to achieve high precision; adopts the driving nail to install the diameter The structure of the ball bearing makes the rolling friction between the driving pin and the cam groove, avoids the wear caused by the long-term operation of the sliding friction link, and significantly improves the working stability of the system; the gear and the cam are connected by convex and concave teeth on the end surface And the spring compression structure, when the movement resistance of the objective lens group is too large, the mechanism has an overload protection function.

4. Description of drawings:

Fig. 1 is a schematic diagram of the front view structure of the prior art;

Fig. 2 is a top view structural schematic diagram of the prior art;

Fig. 3 is a structural schematic diagram of the present invention.

5. Specific implementation

The utility model is implemented according to the structure shown in Fig. 3, wherein the material of the motor gear 24, the primary transmission gear 25 and the secondary transmission gear 27 adopts 40 Cr steel, the modulus is 0.5, the reduction ratio is 2.5 and 2, and the machining accuracy is 7 grades The material of the primary transmission shaft 26 and the secondary transmission shaft 30 is No. 45 carbon structural steel; the material of the three-stage transmission pinion 29 and the three-stage transmission gear 31 adopts 40Cr steel, the modulus is 1, and the machining accuracy is 7 grades; The end face boss on the stage transmission gear 31 is 0.3mm high, and the width 54 of the boss coincides with the width of the groove 55 on the left end face of the cam 44, which is one-third of the diameter. And the groove 55 end face on the left end face of the cam 44 is perpendicular to the central hole of 0.01 mm, and the surface finish is 0.004 μm; the center hole of the three-stage transmission large gear 31 and the three-stage transmission shaft 35 adopt a 7-level precision dynamic fit; the three-stage transmission shaft 35 is made of 40Cr steel; the material of cam 44 is made of 40Cr, the width of cam groove 45 is 5μm-8μm larger than the diameter of the bearing on the drive nail, the machining error of groove width is not more than 8μm, and the groove depth is larger than the bearing width according to the allowable space. The bottom surface can be scratched; the driving nail 49 is made of 40Cr steel; the material of the mirror base 51 and the linear guide rail 52 is GCr15, and the mirror base 51 and the linear guide rail 52 are ground together, with a gap of 8 μm to 10 μm; the linear through groove 53 on the mirror base 51 The width ratio drives the nail 48 to reach 0.1mm; the material of the gear case 43 and the case side cover 38 is 2A12, and the shaft hole on the gear case 43 and the shaft hole on the case side cover 38 are processed in combination; the spring sleeve 34 material can be 2A12.

Claims (1)

1. A focusing mechanism that adopts cam transmission to realize the focusing of a TV telescope, including a motor, a motor gear, a primary transmission shaft, a secondary transmission shaft, a primary transmission large gear, a secondary transmission small gear, and a secondary transmission large gear , a three-stage transmission pinion, a three-stage transmission gear, a gear box, a linear guide rail, a mirror holder, an optical objective lens group, and a driving nail; it is characterized in that it also includes a retaining ring (32), a set screw (33), a spring sleeve (34), tertiary drive shaft (35), bearing cover (36), bearing (37), side cover plate (38), preload nut (39), spring (40), ball (41), cam (44), cam groove (45), bearing (46), bearing end cover (47), bearing (48), straight line through groove (53), end face boss (54), end face groove (55); The upper side of the casing (43) is equipped with a motor (42), and the shaft of the motor (42) stretches into the casing, and the inside of the gear casing (43) is sequentially equipped with a first-stage drive shaft (26), two Stage transmission shaft (30), three-stage transmission shaft (35), the bearing (46) of specification is all housed on the right-hand end shaft head of these three axles, stretches in the shaft hole of gear box body (43), on the left side Bearings (37) with the same specification are all housed on the shaft head, stretch in the shaft hole of the gear box side cover plate (38), and the outside is sealed with the same bearing cover (36), and the bearing cover (36) is fixed with screws ; The motor gear (24) is installed on the shaft of the motor (42), and the two are fixedly connected; The secondary transmission pinion (27) at the left end of the primary transmission shaft (26) meshes with the secondary transmission bull gear (28) at the left end of the secondary transmission shaft (30), and is installed on the secondary transmission shaft (30) ) the tertiary transmission pinion (29) on the right end meshes with the tertiary transmission bull gear (31) on the tertiary transmission shaft (35); the boss (54) on the right end of the tertiary transmission bull gear (31) Mesh with the groove (55) at the left end of the cam (44); on the left side of the three-stage transmission bull gear (31) on the three-stage transmission shaft (35), balls (41), retaining ring ( 32), spring (40), spring sleeve (34), pre-tightening nut (39); the ball (41) is installed in the ball nest of the three-stage transmission gear (31), and the retaining ring (32) presses it from the left side The ball (41); the spring sleeve (34) is sleeved on the third-stage transmission shaft (35) from the left side, the right end is pushed against the shaft shoulder, and the left end is in contact with the inner ring of the bearing (37); the spring (40) is sleeved on the third-stage transmission shaft On the shaft (35), the right end is on the retaining ring (32), the left end is pre-tightened with a pre-tightening nut (39), and the pre-tightening nut (39) is fixed with a set screw (33); the three-stage transmission shaft (35) Bearing (37) is loaded onto the left axle head, stretches in the axle hole of gear box body (43), and bearing end cover is added on the outside; 43), on the linear guide rail (52), there is a linear through groove (53), which provides a moving space for the driving nail (49), and the upper end of the driving nail (49) is equipped with a bearing (48), which extends into the cam (44) In the cam groove (45), the lower end of the driving nail (49) passes through the linear through groove (53) on the linear guide rail (52), and is fixedly connected with the mirror holder (51) with screws, and the optical objective lens group (50) is contained in the mirror In the seat (51).

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