Same-optical-axis self-guiding linear focusing device for space camera

Abstract

The invention relates to the technical field of optical focusing, in particular to a co-optical-axis self-guiding linear focusing device for a space camera, which comprises a sliding base, a focusing base assembly, a tooth cam, a ball retainer, a first ball, a guiding pin shaft and a driving assembly, the tooth cam is driven by the driving assembly to rotate, so that the guide pin shaft pushes the sliding base to linearly move along the central axis under the guide of the first ball; the same-optical-axis design of the focusing device is realized by adopting tooth cam transmission, so that the device is compact in structural layout and high in integration level; the sliding base and the focusing base assembly form an independent complete assembly, so that modular design is facilitated; the guide pin shaft, the ball retainer and the first ball are matched, so that friction force is reduced, and smooth movement is guaranteed; the tooth cam is matched with the driving assembly to achieve conversion from rotation to linear motion. The problems that an existing space optical remote sensing camera focusing mechanism is loose in structure, difficult in modularization, prone to clamping stagnation and the like are solved.

Description

Technical Field

[0001] The present invention belongs to the technical field of optical focusing, and particularly relates to a coaxial and self-guided linear focusing device for a space camera. Background Art

[0002] A space optical remote sensing camera is affected by factors such as vibration, shock during the launch phase and changes in the operating environment temperature, which will cause system aberration and a decline in imaging quality. Usually, three methods of moving the lens group, moving the mirror, and moving the image plane are used to adjust the defocus amount of the camera. With the development of microsatellites, micro-nano optical payloads show a development trend of deep coupling, high integration, ultra-light and small size. At the same time, more stringent requirements are put forward for the focusing mechanism of optical cameras. It not only needs to be structurally compact and light in weight, but also needs to have a large load capacity and high precision. The commonly used focusing mechanism types in orbit are mainly ball screw mechanisms and cam mechanisms. The movement axis of the ball screw mechanism often can only be installed offset relative to the optical axis, and additional guiding devices such as guide rails need to be configured, which affects the compact integration of the structure. Cam mechanisms, especially cylindrical cams, can compactly achieve the coaxial installation of the movement axis and the optical axis, and are often used in the field of zoom lens design. The invention patent application with the Chinese patent publication number CN114185147A, publication date of March 15, 2022, and patent name of "A zoom lens structure for ensuring optical axis consistency" and the invention patent application with the Chinese patent publication number CN102313961A, publication date of January 11, 2012, and patent name of "A cam focusing mechanism using backlash-free gears" are both using this kind of focusing type. The invention patent application with the Chinese patent publication number CN111208692A, publication date of May 29, 2020, and patent name of "Space camera focusing mechanism" proposes a curved surface cam focusing type, which can also be coaxially installed to achieve focusing.

[0003] However, the cylindrical cam focusing design in Patent Document 1 and Patent Document 2 is seriously coupled with the lens design, which is not conducive to the modular design of space optical remote sensing cameras. The design of the transmission part of the curved surface cam in Patent Document 3 is slightly insufficient in compactness, and the cam surfaces on its two end faces need to be processed separately, which is not conducive to ensuring consistency and has a risk of jamming. Summary of the Invention

[0004] In view of this, the present invention aims to provide a coaxial and self-guided linear focusing device for a space camera to solve the problems of loose structure, difficult modularization and easy jamming of the existing focusing mechanism of space optical remote sensing cameras.

[0005] To achieve the above object, the technical solution of the present invention is realized as follows: A coaxial and self-guided linear focusing device for a space camera, comprising a sliding base, a focusing base assembly, a tooth cam, a ball cage, a first ball, a guiding pin shaft and a driving assembly; the sliding base is a cylindrical structure with at least one open end, the focusing base assembly is sleeved outside the cylinder, and a guiding groove is axially formed on the focusing base assembly; the tooth cam is sleeved outside the focusing base assembly, and a cam groove is circumferentially formed on the tooth cam; the ball cage is arranged between the sliding base and the focusing base assembly, an avoidance groove is axially formed on the ball cage, and the first ball is rotatably arranged on the ball cage; one end of the guiding pin shaft sequentially passes through the cam groove, the guiding groove and the avoidance groove and then is connected with the cylinder, and at least part of the free end of the guiding pin shaft is located in the cam groove; the driving assembly is arranged on the focusing base assembly, and the driving assembly drives the tooth cam to rotate, so as to push the guiding pin shaft to drive the sliding base to move linearly along the central axis direction of the sliding base under the guidance of the first ball.

[0006] Further, the focusing base assembly includes a base body, a sensing element and a triggering element. The base body includes a sleeve sleeved outside the cylinder and a first flange arranged at the end of the sleeve, and the guiding groove is arranged on the sleeve; the sensing element and the driving assembly are both arranged on the end face of the first flange, and the triggering element is arranged on the tooth cam and can rotate synchronously therewith to trigger the sensing element to generate a response and feedback position information.

[0007] Further, a wire outlet groove and an external mounting interface are further arranged on the end face of the first flange, and the position of the wire outlet groove is correspondingly arranged with the position of the sensing element.

[0008] Further, the tooth cam includes a driving cam cylinder, gear teeth and a reinforcing ring. The driving cam cylinder is sleeved outside the sleeve, and the cam groove is arranged on the cylinder wall of the driving cam cylinder; the gear teeth are circumferentially arranged on the outside of the driving cam cylinder, the reinforcing ring is arranged at the port of one end of the driving cam cylinder, and the gear teeth and the reinforcing ring are integrally formed with the driving cam cylinder respectively.

[0009] Further, the cam groove includes a spiral section, a straight section and an arc section. The straight section and the arc section are respectively arranged at both ends of the spiral section; the spiral section is arc-shaped along the circumference of the driving cam, one end of the straight section is connected with the spiral section through a fillet transition, and the other end is tangent to the arc section.

[0010] Further, the driving assembly includes a motor, a mounting base, a driving wheel, a transmission wheel, a transmission wheel shaft, bearings, and bearing retaining rings. The mounting base is disposed on the end face of the first flanging. The motor is disposed on the mounting base. The driving wheel is mounted on the output shaft of the motor and fixed. The transmission wheel shaft is disposed on the mounting base and on one side of the driving wheel. The transmission wheel is sleeved on the transmission wheel shaft and fixed. Two bearings are respectively mounted at both ends of the transmission wheel shaft and axially limited by the bearing retaining rings. Wherein, the transmission wheel meshes with the driving wheel and the gear teeth respectively.

[0011] Further, the focusing device further includes a retaining ring, a snap ring, and second balls. The retaining ring and the snap ring are respectively disposed at both ends of the ball cage and respectively connected to the sleeve to axially position the ball cage. And a rotation prevention structure is provided between the ball cage and the snap ring to prevent relative rotation therebetween. Chamfers are respectively provided at both ends of the inner wall of the driving cam cylinder. A plurality of second balls are respectively disposed between the two chamfers and the base body. At least a part of the retaining ring presses on the spherical surface of the second balls on the side away from the first flanging. The second balls on the side close to the first flanging are limited by the first flanging.

[0012] Further, through holes are formed in the ball cage. The first balls are rollably disposed in the through holes. The through holes are arranged in multiple columns along the circumferential direction of the ball cage, and the multiple columns of through holes are obliquely arranged relative to the rotation axis of the ball cage.

[0013] Further, mounting holes are formed in the barrel wall of the cylinder body. The guiding pin shaft is inserted into the mounting holes and is in interference fit with the mounting holes.

[0014] Further, the focusing device further includes a safety screw. A threaded hole is axially formed at one end of the guiding pin shaft inserted into the mounting hole. The safety screw is inserted into the threaded hole to fix the guiding pin shaft inserted into the mounting hole, and the head of the safety screw abuts against the inner wall of the cylinder body.

[0015] Compared with the prior art, the present invention can achieve the following beneficial effects: The present invention realizes the coaxial optical design of the focusing device by adopting a toothed cam drive, making the device structure layout compact and having a high integration degree; the setting of the sliding base and the focusing base assembly makes the focusing device form a complete and independent assembly, facilitating modular integrated design; through the cooperation of the guiding pin shaft with the ball cage and the first ball, the sliding base can move along the central axis, reducing the friction force and ensuring the smoothness of the movement; the cooperation of the toothed cam and the driving assembly realizes the conversion from rotational motion to linear motion, and the driving method is simple and reliable, facilitating control and operation. It solves the problems of the existing focusing mechanism of space optical remote sensing cameras, such as non-compact structure, difficulty in modularization, and easy jamming. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation to the present invention. In the drawings: Figure 1 FIG. is a schematic diagram of the overall structure of the focusing device provided by the embodiment of the present invention; Figure 2 FIG. is a top view structure diagram of the focusing device provided by the embodiment of the present invention; Figure 3 is Figure 2 the sectional structure diagram of A-A in Figure 4 is Figure 2 the sectional structure diagram of B-B in Figure 5 is Figure 2 the sectional structure diagram of C-C in Figure 6 (a) is a schematic diagram of the structure of the focusing base assembly provided by the embodiment of the present invention; Figure 6 (b) is Figure 6 the left view structure diagram of (a); Figure 7 is another perspective structure diagram of the focusing base assembly provided by the embodiment of the present invention; Figure 8 is a schematic diagram of the structure of the toothed cam provided by the embodiment of the present invention; Figure 9 is a schematic diagram of the structure of the driving assembly provided by the embodiment of the present invention; Figure 10 is a schematic diagram of the structure of the ball cage and the retaining ring provided by the embodiment of the present invention.

[0017] Description of the reference numerals: 1. Sliding base; 101. Cylinder; 102. Pressing surface; 103. Second flanging; 104. Load mounting interface; 2. Focusing base assembly; 201. Sleeve; 202. First flanging; 2021. Wire outlet groove; 2022. External mounting interface; 203. Inductive element; 204. Trigger element; 205. Guide groove; 3. Gear cam; 301. Driving cam cylinder; 302. Gear teeth; 303. Reinforcing ring; 304. Cam groove; 3041. Spiral section; 3042. Straight section; 3043. Arc section; 305. Chamfer; 306. Component bracket; 4. Ball retainer; 401. Avoidance groove; 402. Through hole; 5. First ball; 6. Guide pin shaft; 7. Driving assembly; 701. Motor; 702. Mounting base; 703. Driving wheel; 704. Driven wheel; 705. Driven wheel shaft; 706. Bearing; 707. Bearing retainer ring; 8. Retaining ring; 9. Circlip; 10. Second ball; 11. Safety screw. Detailed implementation mode

[0018] In order to make the objectives, technical solutions and advantages of the present invention clearer, the following further details the present invention in conjunction with the attached drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and do not constitute a limitation to the present invention. Similar elements in different embodiments adopt related similar element numbers. In the following embodiments, many detailed descriptions are provided to make the present invention better understood. However, those skilled in the art can easily recognize that some of the features can be omitted in different situations, or can be replaced by other elements, materials, or methods. In some cases, some operations related to the present invention are not shown or described in the specification, in order to avoid the core part of the present invention being overwhelmed by excessive descriptions. For those skilled in the art, it is not necessary to describe these related operations in detail, and they can fully understand the related operations based on the description in the specification and the general technical knowledge in the field.

[0019] It should be noted that, without conflict, the embodiments and features in the embodiments of the present invention can be combined with each other to form various implementation manners. At the same time, the steps or actions in the method description can also be reordered or adjusted in an obvious manner by those skilled in the art. Therefore, the various sequences in the specification and drawings are only for clearly describing a certain embodiment and do not mean that they are the necessary sequences, unless it is stated that a certain sequence must be followed.

[0020] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention. In addition, the terms "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first", "second", etc. may explicitly or implicitly include one or more of such features. In the description of the present invention, unless otherwise specified, the meaning of "a plurality" is two or more.

[0021] In the description of the present invention, it should be noted that unless otherwise clearly defined and limited, the terms "mounted", "connected", "coupled" should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood through specific situations.

[0022] The present invention will be described in detail below with reference to the drawings and in conjunction with embodiments.

[0023] As Figures 1 to 10 shown, this embodiment provides a coaxial and self-guided linear focusing device for a space camera, which includes a sliding base 1, a focusing base assembly 2, a toothed cam 3, a ball cage 4, a first ball 5, a guiding pin shaft 6, and a driving assembly 7. The sliding base 1 can be a cylindrical body 101 structure with both ends open. The focusing base assembly 2 is coaxially sleeved outside the cylindrical body 101, and there is a gap between the two, so that the focusing base assembly 2 can axially slide or rotate relative to the sliding base 1.

[0024] The toothed cam 3 is coaxially sleeved outside the focusing base assembly 2, and the toothed cam 3 can axially slide or rotate relative to the focusing base assembly 2. In this way, the outer wall surface of the focusing base assembly 2 is directly used as the installation reference, without occupying additional axial or radial space, and its structure is compact.

[0025] The ball cage 4 has a cylindrical structure with open ends at both ends and is coaxially installed between the sliding base 1 and the focusing base assembly 2. A plurality of first balls 5 are provided, and the plurality of first balls 5 are all rotatably installed on the ball cage 4. When relative movement occurs between the sliding base 1 and the focusing base assembly 2, the rolling friction of the balls is much smaller than the sliding friction, which can significantly reduce the frictional force between the two, reduce energy loss, and improve the operating efficiency of the device. At the same time, due to the rolling characteristics of the balls, the relative movement between the sliding base 1 and the focusing base assembly 2 becomes smoother and more precise, which can improve the accuracy and repeatability of focusing.

[0026] Two guiding grooves 205 are symmetrically formed along the axial direction of the focusing base assembly 2; two cam grooves 304 are formed along the circumferential direction of the gear cam 3, and the positions of the two cam grooves 304 correspond to those of the two guiding grooves 205 one by one; two avoiding grooves 401 are symmetrically formed along the axial direction of the ball cage 4, and the positions of the two avoiding grooves 401 correspond to those of the two guiding grooves 205 one by one. Two guiding pins 6 are correspondingly provided. One end of each guiding pin 6 sequentially passes through the cam groove 304, the guiding groove 205, and the avoiding groove 401 and then is connected to the cylinder 101, and at least a part of the free end of the guiding pin 6 is located in the cam groove 304. When the gear cam 3 rotates, the cam groove 304 will exert a force on the guiding pin 6. Since the other end of the guiding pin 6 is connected to the cylinder 101, the circular motion of the gear cam 3 is converted into the axial motion of the cylinder 101. The guiding groove 205 provides a guiding function for the movement of the guiding pin 6, ensuring that the cylinder 101 can perform precise linear motion along the axial direction of the focusing base assembly 2, realizing efficient motion transmission. At the same time, due to the provision of two symmetric guiding grooves 205, cam grooves 304, and avoiding grooves 401 and the corresponding guiding pins 6, the balance and synchronism of the cylinder 101 during the movement can be ensured. The phenomenon that the cylinder 101 tilts or jams due to uneven force is avoided, making the focusing process smoother and more stable.

[0027] The driving assembly 7 is arranged on the focusing base assembly 2. The driving assembly 7 drives the gear cam 3 to rotate, thereby pushing the guiding pin 6 to drive the sliding base 1 to perform linear motion along the central axis direction of the sliding base 1 under the guidance of the first balls 5. The driving assembly 7 is arranged on the focusing base assembly 2, shortening the power transmission path, reducing energy loss and transmission error, and improving the efficiency of power transmission. At the same time, integrating the driving assembly 7 on the focusing base assembly 2 makes the structure of the entire focusing system more compact. Through the rotation of the gear cam 3, the rotational motion is converted into the linear motion of the guiding pin 6, and then the sliding base 1 is pushed to perform linear motion, realizing the effective conversion of the power form.

[0028] During actual use, the driving component 7 drives the toothed cam 3 to rotate relative to the focusing base component 2. The cam groove 304 exerts a force on the guiding pin shaft 6, converting the circular motion of the toothed cam 3 into the axial motion of the sliding base 1. The guiding groove 205 guides the motion of the guiding pin shaft 6, ensuring that the sliding base 1 moves precisely in a straight line along the axis of the focusing base component 2. Meanwhile, during the axial linear motion of the sliding base 1, the first ball 5 rolls on the ball retainer 4, making the relative motion between the two smoother.

[0029] Through the above technical solution, the coaxial design of the focusing device is achieved by using the transmission of the toothed cam 3, making the device structure layout compact and having a high degree of integration. The settings of the sliding base 1 and the focusing base component 2 make the focusing device form a complete and independent component, facilitating modular integrated design. Through the cooperation of the guiding pin shaft 6 with the ball retainer 4 and the first ball 5, the sliding base 1 can move along the central axis, reducing the friction force and ensuring the smoothness of the motion; the cooperation of the toothed cam 3 and the driving component 7 realizes the conversion from rotational motion to linear motion, and the driving method is simple and reliable, facilitating control and operation. It solves the problems of the existing focusing mechanism of space optical remote sensing cameras, such as non-compact structure, difficulty in modularization, and easy jamming.

[0030] In some embodiments, the focusing base component 2 may include a base body, a sensing element 203, and a triggering element 204. The base body may include a sleeve 201 sleeved outside the cylinder body 101 and a first flange 202 provided at the end of the sleeve 201. Two guiding grooves 205 are symmetrically arranged on the sleeve 201. Both the sensing element 203 and the driving component 7 are arranged on the end face of the first flange 202. Multiple sensing elements 203 are provided and are equally spaced on the same circle with the axis of the sleeve 201 as the center. Multiple equally spaced sensing elements 203 can achieve a higher position detection resolution. The smaller the angular interval between adjacent sensing elements 203, the more precisely the small rotation of the toothed cam 3 can be detected, thus meeting the application scenarios with high requirements for focusing accuracy. A component bracket 306 is provided along the radial direction of the toothed cam 3, and a corresponding triggering element 204 is installed on the component bracket 306, and the triggering element 204 can rotate synchronously with the toothed cam 3 to trigger the sensing element 203 to respond and feedback position information. With such a setting, the rotational position of the toothed cam 3 can be accurately feedback, and then the axial position of the sliding base 1 can be determined, providing accurate position information for the focusing operation.

[0031] Furthermore, the component bracket 306 is detachably connected to the tooth cam 3, so that during the assembly process, the tooth cam 3 can be installed separately first, and then the component bracket 306 can be flexibly installed according to actual needs to adjust the position of the trigger element 204, ensure that the trigger element 204 and the sensing element 203 are accurately matched, and improve the installation efficiency and position accuracy. If the trigger element 204 or the component bracket 306 is damaged during use, or the position of the sensing element 203 needs to be adjusted, the component bracket 306 can be directly disassembled for repair or replacement without disassembling the entire tooth cam 3, reducing the difficulty and cost of maintenance.

[0032] In some embodiments, a wire outlet slot 2021 and an external installation interface 2022 are also provided on the end surface of the first flange 202, and the position of the wire outlet slot 2021 is set corresponding to the position of the sensing element 203. The number of wire outlet slots 2021 corresponds to the number of sensing elements 203. The setting of the wire outlet slots 2021 allows the connection wires of the sensing elements 203 to be arranged through the corresponding wire outlet slots 2021, thereby ensuring the regularity of the wiring. The entanglement of the wire harness is avoided, the possibility of mutual interference between the lines is reduced, and the stability and reliability of the entire system are improved. At the same time, since the wire outlet slots 2021 correspond to the positions of the sensing elements 203, it is convenient for maintenance personnel to quickly and accurately perform line maintenance and improve installation efficiency. The external installation interface 2022 includes eight perforations arranged at equal intervals on the end surface of the first flange 202. The positions of the perforations can be designed according to actual needs and are not limited here. The setting of the external installation interface 2022 enables the focusing device to be conveniently connected to external equipment, and the staff can quickly and accurately complete the connection operation, thereby improving work efficiency.

[0033] In some embodiments, the tooth cam 3 may include a driving cam barrel 301, gear teeth 302, and a reinforcing ring 303. The driving cam barrel 301 is sleeved on the outside of the sleeve 201, and two cam grooves 304 are provided on the barrel wall of the driving cam barrel 301. The gear teeth 302 are provided on the outside of the driving cam barrel 301 along the circumference of the driving cam barrel 301, so as to facilitate cooperation with the driving assembly 7. The driving assembly 7 can accurately transmit power to the driving cam barrel 301 by meshing with the gear teeth 302, so as to realize the rotation of the driving cam barrel 301. This design makes the power transmission more direct and efficient, and reduces energy loss and transmission error.

[0034] The reinforcing ring 303 is arranged at the port at one end of the driving cam barrel 301 to strengthen the structural strength of the end of the driving cam barrel 301 and prevent the port from being deformed or damaged during use. In particular, when subjected to large external forces or frequent movements, the reinforcing ring 303 can play a reinforcing role, ensure the stability of the overall structure of the gear cam 3, and extend its service life.

[0035] Further, the gear teeth 302 and the reinforcing ring 303 are integrally formed with the driving cam barrel 301. This arrangement avoids problems such as loosening and fracture at the connection parts that may be caused by methods such as welding and bolt connection. The integrally formed structure makes the connection between the various parts of the gear cam 3 tighter and more secure, improving the reliability and durability of the entire gear cam 3. At the same time, since the gear cam 3 is a whole structure, during the assembly process, it only needs to be sleeved outside the sleeve 201, without the need for complex component assembly and debugging work. This not only improves the assembly efficiency but also reduces the assembly difficulty and reduces the possible errors during the assembly process.

[0036] In some embodiments, the cam groove 304 may include a spiral section 3041, a straight section 3042, and an arc section 3043. The two ends of the spiral section 3041 are respectively provided with a straight section 3042 and an arc section 3043. Among them, the spiral section 3041 is arranged in an arc shape along the circumferential direction of the driving cam, and the cooperation between its spiral surface and the guiding pin shaft 6 can efficiently convert the rotational motion of the gear cam 3 into the linear motion of the guiding pin shaft 6. One end of the straight section 3042 is connected to the spiral section 3041 with a fillet transition, enabling the guiding pin shaft 6 to achieve a smooth transition when entering or leaving the spiral section 3041, further improving the stability of the motion, thus ensuring the accuracy of the focusing process and reducing the focusing error caused by uneven motion. At the same time, it avoids stress concentration due to sharp corners or sudden changes, reduces impact loads, reduces wear, and extends the service life of the equipment. The setting of the straight section 3042 can, to a certain extent, keep the position of the sliding base 1 relatively stable. When focusing to a specific position, the straight section 3042 can be used to avoid unnecessary displacement of the sliding base 1 caused by the slight rotation of the gear cam 3, improving the focusing accuracy. The other end of the straight section 3042 is tangent to the arc section 3043, which can ensure that the guiding pin shaft 6 maintains continuous contact with the cam groove 304 during the motion process, avoid stress concentration, further reduce impact loads, reduce the mechanical loss of the entire focusing device, and improve the reliability and durability of the equipment.

[0037] In some embodiments, the driving assembly 7 may include a motor 701, a mounting base 702, a driving wheel 703, a transmission wheel 704, a transmission wheel shaft 705, a bearing 706, and a bearing retainer ring 707. Among them, the mounting base 702 is disposed on the end surface of the first flange 202, the motor 701 is disposed on the mounting base 702, and the driving wheel 703 is fixedly connected to the output shaft of the motor 701 and rotatably disposed within the mounting base 702. The transmission wheel shaft 705 is disposed within the mounting base 702 and located between the driving wheel 703 and the tooth cam 3, and the transmission wheel shaft 705 is parallel to the output shaft of the motor 701; the transmission wheel 704 is sleeved on the transmission wheel shaft 705 and fixedly connected thereto, and the transmission wheel shaft 705 provides stable support for the transmission wheel 704. At the same time, the transmission wheel 704 meshes with the driving wheel 703 and the gear teeth 302 respectively, forming a planar transmission structure. By using the meshing transmission of the transmission wheel 704 with the driving wheel 703 and the gear teeth 302, compared with direct drive, the vibration and impact during the transmission process can be reduced, and the rotation of the tooth cam 3 can be made more stable. This helps to improve the accuracy and stability of focusing and avoid focusing errors caused by unstable factors during the transmission process.

[0038] Further, two bearings 706 are provided and respectively installed at both ends of the transmission wheel shaft 705, and axially limited by the bearing retainer ring 707. The design of the double bearings 706 cooperating with the axial limit of the bearing retainer ring 707 can effectively reduce the radial and axial wobbling of the transmission wheel shaft 705 during rotation, ensure the smooth rotation of the transmission wheel 704, and further improve the stability of the entire driving assembly 7.

[0039] In some embodiments, the focusing device may further include a retainer ring 8, a snap ring 9, and a second ball 10. The retainer ring 8 and the snap ring 9 are respectively disposed at both ends of the ball cage 4 and detachably connected to the sleeve 201 by countersunk head screws to axially position the ball cage 4. In this way, it is ensured that the ball cage 4 does not axially move during operation, enabling the first ball 5 to roll stably on the ball cage 4, maintaining the stability of the relative movement between the sliding base 1 and the focusing base assembly 2, and ensuring the stability of the overall structure of the focusing device.

[0040] A rotation prevention structure is provided between the ball cage 4 and the snap ring 9 to prevent relative rotation between the two. The setting of the rotation prevention structure further enhances the positioning effect of the ball cage 4, avoids the ball cage 4 following the ball to slide, increases the friction force, increases the mechanism load, reduces the mechanism transmission performance, and improves the stability and reliability of the entire device during operation. It should be noted that the rotation prevention structure includes but is not limited to protrusions and grooves, keys and keyways, and other mutually cooperating structures, which can be designed according to actual needs and are not limited here.

[0041] At both ends of the inner wall of the driving cam barrel 301, chamfers 305 are respectively provided. A plurality of second balls 10 are provided and are respectively arranged between the two chamfers 305 and the base body. The retaining ring 8 presses at least partially against the spherical surface of the second balls 10 on the side away from the first flanging 202, and the second balls 10 on the side close to the first flanging 202 are limited by the first flanging 202. The second balls 10 convert the sliding friction between the driving cam barrel 301 and the base body into rolling friction, reducing the frictional resistance. At the same time, the pressure generated during the rotation of the driving cam barrel 301 is dispersed, enhancing the stability of the connection between the driving cam barrel 301 and the base body, and avoiding structural damage caused by excessive local stress.

[0042] In some embodiments, through holes 402 are formed in the ball cage 4, and the first balls 5 are rotatably arranged in the through holes 402. This design can ensure that the contact area between the balls and the cage during the rolling process is minimized, thereby significantly reducing the frictional resistance. The first balls 5 can roll freely and flexibly in the through holes 402, reducing energy loss, improving the overall efficiency of the transmission system, and making the operation smoother and more stable. The through holes 402 are arranged in multiple columns along the circumferential direction of the ball cage 4, and the multiple columns of through holes 402 are arranged obliquely with respect to the axis of rotation of the ball cage 4. With this arrangement, the first balls 5 are more dispersed. When the sliding base 1 and the focusing base assembly 2 move relative to each other, the multiple columns of obliquely distributed balls can evenly disperse the load between the two, avoiding excessive local stress, effectively enhancing the load-bearing capacity and service life of the device. Moreover, compared with the vertical arrangement of the through holes 402, it can avoid motion jamming or instability caused by force concentration.

[0043] In some embodiments, mounting holes are formed in the barrel wall of the barrel 101, and the guide pin shafts 6 are inserted into the mounting holes and are in interference fit with the mounting holes. By adopting this connection method, the guide pin shafts 6 can be tightly connected to the barrel 101, forming a firm fixed relationship. During the operation of the focusing device, when the toothed cam 3 rotates and applies a force to the guide pin shafts 6 through the cam groove 304, the interference fit connection method can effectively prevent the guide pin shafts 6 from loosening, falling off or undergoing relative displacement, ensuring that the circular motion of the toothed cam 3 is stably converted into the axial motion of the barrel 101, maintaining the structural stability and working reliability of the entire focusing mechanism, and avoiding focusing failure or equipment damage caused by loose connection.

[0044] In some embodiments, the focusing device further includes a safety screw 11. One end of the guiding pin shaft 6 inserted into the mounting hole is axially provided with a threaded hole. The safety screw 11 is inserted into the threaded hole to fix the guiding pin shaft 6 inserted into the mounting hole, and the head of the safety screw 11 abuts against the inner wall of the cylinder body 101. The guiding pin shaft 6 and the mounting hole itself are initially fixed by interference fit. On this basis, the safety screw 11 is screwed into the threaded hole at one end of the guiding pin shaft 6 to further apply a fastening force axially. Through this double fixing method, the risk of the guiding pin shaft 6 loosening or falling off under complex working conditions (such as high-frequency vibration and large-load impact) is greatly reduced. Even if the interference fit slightly fails due to long-term use, the safety screw 11 can continuously restrain the guiding pin shaft 6 to ensure the stability of the power transmission structure of the focusing device. The head of the safety screw 11 is in close contact with the inner wall of the cylinder body 101 to form a rigid support point, effectively restricting the small displacement of the guiding pin shaft 6 in the radial or circumferential direction. During the process of the tooth cam 3 driving the guiding pin shaft 6 to convert the motion form, the safety screw 11 can assist in eliminating the potential clearance caused by the interference fit tolerance, ensuring that the guiding pin shaft 6 accurately moves along the predetermined trajectory and maintaining the focusing accuracy.

[0045] Furthermore, a pressing surface 102 is further provided on the inner wall of the cylinder body 101 corresponding to the head of the safety screw 11. The pressing surface 102 is a specific area designed on the inner wall of the cylinder body 101, and its shape is adapted to the head of the safety screw 11, usually a plane or a plane with a slight arc. The head of the safety screw 11 is in close fit with the pressing surface 102, increasing the contact area between the two, providing greater friction, and more effectively preventing the safety screw 11 from loosening, thereby ensuring that the guiding pin shaft 6 is stably installed on the cylinder body 101. Compared with the head of the safety screw 11 directly abutting against the inner wall of the cylinder body 101, the existence of the pressing surface 102 makes the force on the head of the safety screw 11 more evenly distributed on the inner wall of the cylinder body 101. It avoids the deformation or damage of the material of the cylinder body 101 caused by excessive local force and extends the service life of the cylinder body 101.

[0046] Furthermore, the sliding base 1 further includes a second flanging 103. The second flanging 103 is arranged at the end of the cylinder body 101 close to the first flanging 202. Four load mounting interfaces 104 are equally spaced near the edge on the end face of the second flanging 103, providing a fastening mounting interface for the driven load. Due to the equal-spacing distribution, this layout can ensure that the center of gravity is evenly distributed after the load is installed, avoiding uneven force on the sliding base 1 caused by eccentric load installation, so as to maintain stability during the focusing movement, reduce shaking and offset, and ensure the focusing accuracy.

[0047] Furthermore, the guiding pin shaft 6 and the gear cam 3 are designed with different materials to prevent cold welding, the first ball 5 and the ball cage 4 are designed with different materials to prevent cold welding, the sliding base 1 and the retaining ring 9 are designed with different materials to prevent cold welding, and the transmission wheel 704 and the gear cam 3, the driving wheel 703 are designed with different materials to prevent cold welding. In a low-temperature and high-vacuum environment such as space, the contact surfaces of the same material are prone to cold welding, resulting in adhesion between the above-mentioned cooperating structures, causing the mechanism to jam and interlock, and the equipment to lose its focusing function. Therefore, the design with different materials to prevent cold welding can effectively destroy the conditions for cold welding to form, prevent the mutual diffusion and combination of the surface atoms of the two, ensure that the guiding pin shaft 6 can always move freely in the cam groove 304, or the first ball 5 can always roll freely in the through hole 402 of the ball cage 4, or the sliding base 1 and the retaining ring 9 can always maintain the flexibility of relative movement, or the transmission wheel 704 can always maintain a good meshing relationship with the gear cam 3 and the driving wheel 703, ensuring the long-term stable operation of the focusing device in extreme environments, extending its service life, and reducing the equipment maintenance and replacement costs.

[0048] Furthermore, the heat treatment hardness of the guiding pin shaft 6 is HRC45 - 66, and the heat treatment hardness of the sliding base 1 and the focusing base assembly 2 at the section cooperating with the first ball 5 is HRC45 - 66. The heat treatment hardness reaching HRC45 - 66 endows it with high strength and wear resistance. During the focusing process, the gear cam 3 rotates and applies a force to the guiding pin shaft 6 through the cam groove 304. The high-hardness guiding pin shaft 6 can withstand large shear forces and extrusion stresses and is not prone to deformation or fracture. It ensures that the circular motion of the gear cam 3 is stably and accurately converted into the linear motion of the sliding base 1, maintaining the normal operation of the focusing device. The sliding base 1 and the focusing base assembly 2 achieve relative movement through the first ball 5, and there is continuous rolling friction among the three. The higher heat treatment hardness enables the cooperating section surface to have stronger anti-wear ability, effectively resisting the surface loss caused by the rolling of the first ball 5. Even after long-term and high-frequency focusing actions, the surface of the cooperating section is not prone to severe wear, thereby extending the service lives of the sliding base 1, the focusing base assembly 2, and the first ball 5, and reducing the frequency of equipment maintenance and component replacement.

[0049] Furthermore, the surfaces of the first ball 5 and the second ball 10 are plated with molybdenum disulfide. The molybdenum disulfide coating can form a protective film on the surface of the ball, playing a role in isolation and buffering, and reducing the direct wear between the ball and the contact components. After the surfaces of the first ball 5 and the second ball 10 are plated with molybdenum disulfide, the friction coefficient of the ball during rolling can be significantly reduced. When the focusing device is operating, the frictional force between the ball and the contact components (such as the ball cage 4, the chamfer 305 of the driving cam barrel 301, etc.) is reduced, which can reduce energy loss and improve the operating efficiency of the focusing device. At the same time, it can also reduce the heat generated by friction and avoid the degradation or damage of component performance caused by overheating. Thereby improving the reliability and focusing accuracy of the focusing device.

[0050] Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those of ordinary skill in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present invention.

[0051] The above specific embodiments of the present invention do not constitute a limitation to the protection scope of the present invention. Any other corresponding changes and deformations made according to the technical concept of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A co-optical axis, self-guided linear focusing device for a space camera, characterized in that: It includes a sliding base, a focusing base assembly, a gear cam, a ball holder, a first ball, a guide pin shaft and a driving assembly; The sliding base is a cylindrical structure with at least one end open, the focusing base assembly is sleeved on the outside of the cylindrical body, and the focusing base assembly is provided with a guide groove opened along its axial direction; the tooth cam is sleeved on the outside of the focusing base assembly, and the tooth cam is provided with a cam groove along its circumference; the ball holder is arranged between the sliding base and the focusing base assembly, and the ball holder is provided with an avoidance groove opened along its axial direction, and the first ball is rollingly arranged on the ball holder; one end of the guide pin shaft passes through the cam groove, the guide groove and the avoidance groove in sequence and is connected to the cylindrical body, and the free end of the guide pin shaft is at least partially located in the cam groove; the driving assembly is arranged on the focusing base assembly, and the driving assembly drives the tooth cam to rotate, thereby pushing the guide pin shaft to drive the sliding base to perform linear motion along the central axis direction of the sliding base under the guidance of the first ball.

2. The linear focusing device according to claim 1, characterized in that: The focusing base assembly includes a base body, a sensing element and a triggering element. The base body includes a sleeve sleeved on the outside of the barrel and a first flange arranged at the end of the sleeve, and the guide groove is arranged on the sleeve; the sensing element and the driving assembly are both arranged on the end surface of the first flange, and the triggering element is arranged on the tooth cam and can rotate synchronously with it to trigger the sensing element to respond and feedback position information.

3. The linear focusing device according to claim 2, characterized in that: A wire outlet groove and an external installation interface are also provided on the end surface of the first flange, and the position of the wire outlet groove is arranged corresponding to the position of the sensing element.

4. The linear focusing device according to claim 2, characterized in that: The tooth cam includes a driving cam barrel, gear teeth and a reinforcement ring. The driving cam barrel is sleeved on the outside of the sleeve, and the cam groove is arranged on the barrel wall of the driving cam barrel; the gear teeth are arranged on the outside of the driving cam barrel along the circumference of the driving cam barrel, the reinforcement ring is arranged at the port at one end of the driving cam barrel, and the gear teeth and the reinforcement ring are respectively integrally formed with the driving cam barrel.

5. The linear focusing device according to claim 4, characterized in that: The cam groove includes a spiral segment, a straight segment and an arc segment, and the straight segment and the arc segment are respectively provided at both ends of the spiral segment; the spiral segment is arranged in an arc shape along the circumference of the driving cam, one end of the straight segment is connected to the spiral segment rounded transition, and the other end is arranged tangent to the arc segment.

6. The linear focusing device according to claim 4, characterized in that: The driving assembly includes a motor, a mounting base, a driving wheel, a transmission wheel, a transmission wheel shaft, a bearing and a bearing pressure ring. The mounting base is arranged on the end face of the first flange, the motor is arranged on the mounting base, the driving wheel is mounted on the output shaft of the motor and is fixed; the transmission wheel shaft is arranged on the mounting base and is located on one side of the driving wheel, the transmission wheel is sleeved on the transmission wheel shaft and is fixed, two bearings are arranged and are respectively mounted on both ends of the transmission wheel shaft and are axially limited by the bearing pressure ring; wherein, the transmission wheel is respectively meshed with the driving wheel and the gear teeth.

7. The linear focusing device according to claim 4, characterized in that: The focusing device also includes a pressure ring, a retaining ring and a second ball, the pressure ring and the retaining ring are respectively arranged at both ends of the ball holder and are respectively connected to the sleeve to axially position the ball holder, and a rotation-stop structure is arranged between the ball holder and the retaining ring to prevent relative rotation between the two; chamfers are respectively provided at both ends of the inner wall of the driving cam barrel, a plurality of second balls are arranged and are respectively arranged between the two chamfers and the base body, the pressure ring is at least partially pressed against the spherical surface of the second ball away from the first flange side, and the second ball close to the first flange side is limited by the first flange.

8. The linear focusing device according to claim 1, characterized in that: The ball retainer is provided with a through hole, and the first ball is rollingly arranged in the through hole; the through holes are arranged in multiple rows along the circumference of the ball retainer, and the multiple rows of through holes are arranged obliquely relative to the rotation axis of the ball retainer.

9. The linear focusing device according to claim 1, characterized in that: A mounting hole is provided on the cylinder wall of the cylinder body, and the guide pin shaft is inserted into the mounting hole and is interference fit with the mounting hole.

10. The linear focusing device according to claim 9, characterized in that: The focusing device also includes a safety screw, and a threaded hole is opened along the axial direction of one end of the guide pin shaft inserted into the mounting hole. The safety screw is inserted into the threaded hole to fix the guide pin shaft inserted into the mounting hole, and the head of the safety screw abuts against the inner wall of the cylinder.

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