Cam focusing mechanism and ray machine structure
Through a cam focus mechanism composed of three-layer cylindrical cylindrical parts, the focus accuracy and continuous rotation problems of the existing cam focus mechanism are solved, and high-precision and stable optical system design are achieved.
Patent Information
- Application Number
- CN202510659166.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-05-21
- Publication Date
- 2025-08-01
AI Technical Summary
The existing cam focus mechanism has problems such as poor focus accuracy and inability to rotate continuously in the transmitting optical system, especially the cam groove design leads to empty back and requires multiple limit switches, which affects the coaxiality and accuracy of the system.
The cam focus mechanism composed of three-layer cylindrical cylindrical parts includes a focus lens barrel, a focus frame and a focus cam. Driven by a single-sided cam groove with a dual-period sinusoidal curve and a DC servo motor, the continuous rotation and high-precision position control of the focus mirror are realized, and the focus gap and empty return are eliminated.
It realizes high-precision position control and continuous rotation of the focus mirror, without multiple limit switches, reduces the volume and design difficulty of the optical machine system, and improves the stability and failure rate of the system.
Smart Images
Figure CN120405889A_ABST
Abstract
Description
Technical Field
[0001] The present application relates to optical system technology, and particularly to a cam focusing mechanism and an optical-mechanical structure. Background Art
[0002] In a transmissive optical system, in order to adapt to different object distances or perform high and low temperature compensation, one or a group of lenses need to perform a translational movement along the optical axis direction, which requires a focusing mechanism to drive the focusing lens. In a transmissive optical system, a cylindrical cam focusing mechanism is relatively common. The focusing mechanism needs to keep the coaxiality and straightness of the optical axis of the focusing lens and the optical axis of the system during the translational movement of the focusing lens, and at the same time ensure the accuracy of the translational movement.
[0003] In the existing cam focusing mechanism, the cam groove is generally an ordinary spiral groove, and the cam cannot rotate continuously. Generally, two electrical limit switches or marking the two ends through a stall mark are required. Moreover, there is generally backlash in the existing cam grooves, and the focusing accuracy is poor. Summary of the Invention
[0004] The embodiments of the present application provide a cam focusing mechanism and an optical-mechanical structure, so that the focusing lens has a high position accuracy, and at the same time the focusing cam can rotate continuously without jamming points.
[0005] The embodiments of the present application provide a cam focusing mechanism, including:
[0006] A focusing lens frame 3;
[0007] A focusing lens barrel 4, which is arranged in the focusing lens frame 3. A focusing compression spring 9 is arranged between the rear end face of the focusing lens barrel 4 and the inner end face of the focusing lens frame 3, and a focusing lens 5 is installed therein;
[0008] A focusing cam 6, which is arranged outside the focusing lens frame 3. A set of opposite linear waist-shaped grooves are arranged on the cylindrical surface of the focusing lens frame 3; at one end of the focusing cam 6, a unilateral cam groove with a double-period sine curve is arranged, and at the other end, a gear structure is arranged. The cam groove of the focusing cam 6 and the waist-shaped groove of the focusing lens frame 3 interact to convert the rotation of the focusing cam 6 into a linear movement of the focusing lens barrel 4;
[0009] A DC servo motor 1, on the output shaft of which a driving gear 2 is arranged, and the driving gear 2 meshes with the gear structure on the focusing cam 6 to drive the focusing cam to rotate.
[0010] The embodiments of the present application also provide an optical-mechanical structure, including the cam focusing mechanism as described above.
[0011] The focusing mechanism of the embodiment of the present application mainly consists of three cylindrical parts. From the inside to the outside, they are the focusing lens barrel, the focusing lens frame, and the focusing cam. There is a clearance fit between the three cylindrical parts, which can ensure high position accuracy of the focusing lens. At the same time, the focusing cam can rotate continuously without jamming.
[0012] The above description is only an overview of the technical solution of the present application. In order to understand the technical means of the present application more clearly, it can be implemented according to the content of the specification. And in order to make the above and other purposes, features, and advantages of the present application more obvious and understandable, the following specific embodiments of the present application are given. Brief Description of the Drawings
[0013] By reading the detailed description of the preferred embodiments below, various other advantages and benefits will become clear to those of ordinary skill in the art. The drawings are only for the purpose of showing the preferred embodiments and are not considered to be a limitation of the present application. Moreover, throughout the drawings, the same reference numerals are used to represent the same components. In the drawings:
[0014] Figure 1 It is a schematic diagram of the overall structure of the cam focusing mechanism of the embodiment of the present application;
[0015] Figure 2 It is a schematic diagram of the side sectional structure of the cam focusing mechanism of the embodiment of the present application;
[0016] Figure 3 It is a schematic diagram of the partial sectional structure of the cam focusing mechanism of the embodiment of the present application;
[0017] Figure 4 It is a schematic diagram of the focusing cam structure of the cam focusing mechanism of the embodiment of the present application. Detailed Description of the Embodiments
[0018] The exemplary embodiments of the present disclosure will be described in more detail below with reference to the drawings. Although the exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided so that the present disclosure can be more thoroughly understood and the scope of the present disclosure can be completely conveyed to those skilled in the art.
[0019] The embodiment of the present application provides a cam focusing mechanism. The focusing mechanism of the embodiment of the present application mainly consists of three cylindrical parts. From the inside to the outside, they are the focusing lens barrel 4, the focusing lens frame 3, and the focusing cam 6. There is a clearance fit between the three cylindrical parts. Specifically, as Figure 1 、 Figure 2 、 Figure 3 shown, it includes:
[0020] The focusing lens frame 3;
[0021] The focusing lens barrel 4 is arranged inside the focusing lens frame 3. A focusing compression spring 9 is arranged between the rear end face of the focusing lens barrel 4 and the inner end face of the focusing lens frame 3, and a focusing lens 5 is installed therein. In some embodiments, the focusing compression spring 9 presses the focusing lens barrel 4 onto the cam groove of the focusing cam 6 through a deep groove ball bearing 7. A focusing retaining ring 10 is installed on the rear end face of the focusing lens frame 3. There is a cylindrical structure on the inner side of the focusing retaining ring 10, which extends from the rear end face into the interior of the focusing compression spring 9; there is also a cylindrical structure on the rear end face of the focusing lens barrel 4, which extends from the front end face into the interior of the focusing compression spring 9, playing an auxiliary guiding role for the focusing compression spring 9.
[0022] The focusing cam 6 is arranged outside the focusing lens frame 3. A set of opposite high-precision linear waist-shaped grooves are arranged on the cylindrical surface of the focusing lens frame 3; one end of the focusing cam 6 is provided with a unilateral cam groove with a double-period sine curve, and the other end is provided with a gear structure. The cam groove of the focusing cam 6 and the waist-shaped groove of the focusing lens frame 3 interact to convert the rotation of the focusing cam 6 into a linear motion of the focusing lens barrel 4. In some embodiments, the gear structure is a cylindrical spur gear.
[0023] A DC servo motor 1 is provided with a driving gear 2 on its output shaft. The driving gear 2 meshes with the gear structure on the focusing cam 6 to drive the focusing cam to rotate. The interaction between the cam groove on the focusing cam and the waist-shaped groove on the focusing lens frame can convert the continuous rotation of the focusing cam into a linear reciprocating motion of the focusing lens barrel.
[0024] In some embodiments, the curve corresponding to the cam groove is a double-period sine curve, and the equation is:
[0025]
[0026] This equation is a cylindrical coordinate equation, where R is the radius of the cam cylindrical surface, Z(θ) is the amplitude of the cam curve from the zero position, A is the maximum unilateral focusing amount, and θ is the cam rotation angle. As Figure 4 shown, the saddle-shaped surface is actually obtained by offsetting the bearing radius using this curve equation.
[0027] Due to the action of the focusing compression spring in the embodiment of the present application, the bearing always presses on the unilateral cam groove of the focusing cam, which can eliminate the focusing gap and backlash, thereby improving the focusing accuracy.
[0028] The cam focusing mechanism in the embodiment of the present application adopts a unilateral cam groove and a double-period sine cam curve, which can make the cam rotate continuously, eliminating one switch, and even eliminating the existing two switches. Moreover, it can be arranged at any position in the circumferential direction of the focusing mechanism, thereby reducing the volume and design difficulty of the opto-mechanical system. It can enable the focusing lens to have a high position accuracy, and at the same time, the focusing cam can rotate continuously without jamming.
[0029] In some embodiments, on the cylindrical surface of the focusing lens barrel 4, a set of relatively high coaxiality threaded holes is provided.
[0030] In some embodiments, it further includes two focusing guide posts 8. On any one of the focusing guide posts (8), two deep groove ball bearings 7 are installed.
[0031] The two focusing guide posts 8 pass through the cam grooves of the focusing cam 6 and the linear waist-shaped grooves of the focusing lens frame 3, and are arranged in the relatively threaded holes on the cylindrical surface of the focusing lens barrel 4.
[0032] The deep groove ball bearings 7 on the outer side of the focusing guide post 8 are matched with the cam grooves of the focusing cam 6, and the inner bearings are in clearance fit with the linear waist-shaped grooves of the focusing lens frame 3.
[0033] In some embodiments, on the rear end face of the focusing lens frame 3, a focusing pressure ring 10 is provided, and the inner side of the focusing pressure ring 10 has a cylindrical structure.
[0034] The focusing pressure ring 10 extends into the focusing compression spring 9 from the rear end face; the focusing compression spring 9 presses the focusing lens barrel 4 on the cam groove of the focusing cam (6) through the deep groove ball bearing 7.
[0035] The rear end face of the focusing lens barrel 4 has a cylindrical structure, which extends into the interior of the focusing compression spring 9 from the front end face to assist in guiding the focusing compression spring 9.
[0036] In the cam focusing mechanism of the embodiment of the present application, a focusing lens is installed inside the focusing lens barrel 4, and a set of relatively high coaxiality threaded holes are provided on the cylindrical surface. A set of relatively high-precision linear waist-shaped grooves are provided on the cylindrical surface of the focusing lens frame 3. On one end of the focusing cam 6, a unilateral cam groove with a double-period sine curve is machined, and a cylindrical spur gear is machined on the other end. A focusing compression spring is installed between the rear end face of the focusing lens barrel 4 and the inner end face of the focusing lens frame.
[0037] Two bearings are installed on each focusing guide post. The two sets of focusing guide posts pass through the cam grooves of the focusing cam and the waist-shaped grooves of the focusing lens frame, and are installed in the relatively threaded holes on the cylindrical surface of the focusing lens barrel. The outer bearings are matched with the cam grooves of the focusing cam, and the inner bearings are in clearance fit with the waist-shaped grooves of the focusing lens frame. The focusing compression spring presses the focusing lens barrel on the cam groove of the focusing cam through the bearings. A focusing pressure ring is installed on the rear end face of the focusing mechanism. The inner side of the focusing pressure ring has a cylindrical structure, which extends into the interior of the focusing compression spring from the rear end face; the rear end face of the focusing lens barrel also has a cylindrical structure, which extends into the interior of the focusing compression spring from the front end face to play an auxiliary guiding role for the focusing compression spring.
[0038] The cam focusing mechanism of the present application drives the focusing cam to rotate through a DC motor. The cam groove on the focusing cam interacts with the waist-shaped groove on the focusing lens frame, and the continuous rotation of the focusing cam can be converted into the linear reciprocating motion of the focusing lens barrel. The double-period sine curve enables both groups of bearings to press on the cam simultaneously. The focusing cam can rotate continuously, which can reduce the difficulty of servo control. At the same time, the motor will not stall, and the failure rate can be effectively reduced.
[0039] The embodiment of the present application also provides an opto-mechanical structure, including the cam focusing mechanism as described above.
[0040] It should be noted that in each embodiment of the present application, the term "including", "comprising" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements not only includes those elements, but also includes other elements not expressly listed, or further includes elements inherent to such process, method, article or device. Without further limitation, an element defined by the statement "including one..." does not exclude the existence of additional identical elements in the process, method, article or device including that element.
[0041] The serial numbers of the embodiments of the present application above are only for description and do not represent the superiority or inferiority of the embodiments.
[0042] The embodiments of the present application have been described above in conjunction with the accompanying drawings. However, the present application is not limited to the above specific embodiments. The above specific embodiments are merely illustrative and not restrictive. Under the inspiration of the present application, those of ordinary skill in the art can also make many forms without departing from the purpose of the present application and the scope protected by the claims. All of these are within the protection scope of the present application.
Claims
1. A cam focusing mechanism, characterized in that, Comprising: A focusing lens frame (3); A focusing lens barrel (4), which is arranged inside the focusing lens frame (3). A focusing compression spring (9) is arranged between the rear end face of the focusing lens barrel (4) and the inner end face of the focusing lens frame (3). A focusing lens (5) is installed therein. The focusing compression spring (9) presses the focusing lens barrel (4) onto the cam groove of a focusing cam (6) through a deep groove ball bearing (7); A focusing cam (6), which is arranged outside the focusing lens frame (3). A set of opposite linear waist-shaped grooves are arranged on the cylindrical surface of the focusing lens frame (3); One end of the focusing cam (6) is provided with a unilateral cam groove of a double-period sine curve, and the other end is provided with a gear structure. The cam groove of the focusing cam (6) and the waist-shaped groove of the focusing lens frame (3) interact to convert the rotation of the focusing cam (6) into the linear motion of the focusing lens barrel (4); A DC servo motor (1), on the output shaft of which a driving gear (2) is arranged. The driving gear (2) meshes with the gear structure on the focusing cam (6) to drive the focusing cam to rotate.
2. The cam focusing mechanism according to claim 1, wherein The gear structure is a straight cylindrical gear.
3. The cam focusing mechanism according to claim 1, wherein On the cylindrical surface of the focusing lens barrel (4), a set of opposite coaxial threaded holes are arranged.
4. The cam focusing mechanism according to claim 3, characterized in that, It further includes two focusing guide posts (8). Two deep groove ball bearings (7) are installed on any one of the focusing guide posts (8); The two focusing guide posts (8) pass through the cam groove of the focusing cam (6) and the linear waist-shaped groove of the focusing lens frame (3) and are arranged in the relative threaded holes on the cylindrical surface of the focusing lens barrel (4); The deep groove ball bearing (7) on the outer side of the focusing guide post (8) is matched with the cam groove of the focusing cam (6), and the inner bearing has a clearance fit with the linear waist-shaped groove of the focusing lens frame (3).
5. The cam focusing mechanism according to claim 4, characterized in that, On the rear end face of the focusing lens frame (3), a focusing retaining ring (10) is arranged. The inner side of the focusing retaining ring (10) has a cylindrical structure; The focusing retaining ring (10) extends into the focusing compression spring (9) from the rear end face; The rear end face of the focusing lens barrel (4) has a cylindrical structure, which extends from the front end face into the inside of the focusing compression spring (9) to assist in guiding the focusing compression spring (9).
6. The cam focusing mechanism according to claim 1, wherein The curve corresponding to the cam groove is a double-period sine curve.
7. An optical-mechanical structure, characterized in that, Comprising the cam focusing mechanism according to any one of claims 1-6.