Automatic centering assembly method for high-precision lens cone and lens frame and feeler gauge tool

Abstract

The invention provides a high-precision automatic centering assembly method for a lens barrel and a lens frame and a feeler gauge tool, the automatic centering assembly method comprises the following steps: assembling the lens frame in the lens barrel, and determining the gap size of a radial gap between the lens barrel and the lens frame, selecting a first feeler gauge with a preset specification according to the gap size; the lens frames are sequentially placed in the inner cavity of the lens barrel, and first feeler gauges are symmetrically arranged at the four-quadrant positions of the radial gap; and based on a four-quadrant multidirectional compensation method, applying equal pre-tightening force to a plurality of positions in the radial gap, and gradually adjusting the relative position of the lens frame in the lens barrel, so that the coaxiality and the inclination angle of the lens frame and the lens barrel reach preset precision. The problems of low assembly precision and large coaxiality deviation caused by part manufacturing tolerance and assembly eccentricity in the assembly process of the lens barrel and the lens frame in the prior art are solved.

Description

Technical Field

[0001] This application relates to the field of optical component processing technology, and more specifically, to a high-precision automatic centering assembly method and feeler gauge tool for lens barrel and lens frame. Background Technology

[0002] In the production of high-precision optical systems (such as microscopes, laser rangefinders, and high-definition imaging lenses), it is necessary to ensure that the coaxiality deviation of the assembled lens barrel and frame is controlled within 0.01 mm. However, when the lens barrel and frame are manufactured separately, manufacturing tolerances often result in a tolerance of ±(5~20) μm between the inner diameter of the assembled lens barrel and the outer diameter of the frame. This leads to radial gaps during assembly, causing frame eccentricity and making it impossible to stably control the coaxiality within the 0.01 mm range. Consequently, the optical axis stability of the optical system is affected, ultimately resulting in aberrations and a decrease in resolution.

[0003] Traditional assembly methods, such as the fixed-thickness shim method and the mechanical set screw method, suffer from drawbacks such as poor adaptability, low efficiency, and poor repeatability. Especially when micron-level precision is required, traditional methods are difficult to meet the high-precision requirements of mass production.

[0004] Therefore, existing technologies still need to be improved and developed. Summary of the Invention

[0005] The purpose of this application is to provide a high-precision automatic centering assembly method and feeler gauge tool for lens barrel and frame assembly, which solves the problems of low assembly accuracy and large coaxiality deviation caused by manufacturing tolerances of parts and assembly eccentricity in the assembly process of lens barrel and frame in the prior art.

[0006] To achieve the above objectives, the technical solution adopted in this application is as follows: On one hand, this application provides a high-precision automatic centering assembly method for lens barrel and frame, used to assemble the lens frame inside the lens barrel, wherein the automatic centering assembly method includes the following steps: Determine the radial clearance size between the lens barrel and the lens frame, and select a first feeler gauge of predetermined specifications according to the clearance size; Place the frames into the inner cavity of the lens tube one by one, and symmetrically set the first feeler gauges at the four quadrant positions of the radial gap; Based on the four-quadrant multi-directional compensation method, equal preload is applied at multiple positions within the radial gap to gradually adjust the relative position of the lens frame within the lens barrel, so that the coaxiality and tilt angle of the lens frame and lens barrel reach the predetermined accuracy.

[0007] In an optional embodiment, the step of applying equal preload at multiple locations within the radial clearance to gradually adjust the relative position of the lens frame within the lens barrel, based on the four-quadrant multi-directional compensation method, includes: The relative position of the test frame within the inner cavity of the test tube is detected; According to the relative position, insert a second feeler gauge of the same thickness at a symmetrical position in the four quadrants of the inner cavity of the microscope tube, wherein the thickness of the second feeler gauge is less than the thickness of the first feeler gauge. Repeat the above steps of "detecting the relative position of the lens frame in the inner cavity of the lens barrel" and "inserting a second feeler gauge of the same thickness into the four quadrants of the inner cavity of the lens barrel according to the relative position" until the coaxiality and tilt angle of the lens frame and the lens barrel reach the predetermined accuracy.

[0008] In an optional embodiment, the step of inserting a second feeler gauge of the same thickness at symmetrical positions in the four quadrants of the endoscope tube cavity according to its relative position is as follows: The second feeler gauge is pushed simultaneously at symmetrical positions in the four quadrants by the push rod, so as to apply equal preload at multiple positions.

[0009] In an optional embodiment, in the step of detecting the relative position of the lens frame within the lens barrel cavity: When a residual deviation is detected between the lens barrel and the lens frame, determine the direction and magnitude of the residual deviation; The third feeler gauge is determined based on the magnitude of the residual deviation, wherein the thickness of the third feeler gauge is less than the thickness of the first feeler gauge; The third feeler gauge is added or removed at the corresponding quadrant point of the radial clearance according to the direction of the residual deviation, so that the coaxiality and tilt angle of the lens frame and the lens barrel reach the predetermined accuracy.

[0010] In an optional embodiment, in the step of sequentially placing the lens frame into the inner cavity of the lens barrel and symmetrically setting the first feeler gauge at the four quadrant positions of the radial gap: The first feeler gauge is pushed into the radial clearance using a push rod.

[0011] In an optional embodiment, in the step of pushing the first feeler gauge into the radial clearance by means of a push rod, the push rod includes a housing, an elastic element, and a push head, the elastic element being disposed inside the housing, and the push head being connected to the elastic element and movably disposed at one end of the housing; The pusher head is equipped with a flexible soft rubber layer.

[0012] In an optional embodiment, during the step of pushing the first feeler gauge into the radial clearance via a push rod: The first feeler gauge is pushed into the radial gap by the pressure of the elastic element through the flexible rubber layer at one end of the push rod.

[0013] In an optional embodiment, the step of determining the radial clearance size between the lens barrel and the lens frame, and selecting a first feeler gauge of predetermined specifications according to the clearance size, includes: The outer diameter of the frame and the inner diameter of the lens barrel are accurately measured using a micrometer, and the radial clearance is calculated. The clearance is calculated as 0.5 (outer diameter of the frame - inner diameter of the lens barrel). Select the first feeler gauge from the standardized feeler gauge kit based on the gap size, where the thickness of the first feeler gauge is closest to the gap size.

[0014] In an optional embodiment, the step of calculating the radial clearance dimension by accurately measuring the outer diameter of the frame and the inner diameter of the lens barrel with a micrometer further includes: The clearance dimension is determined to be within the first dimension range; The step of selecting the first feeler gauge from the feeler gauge kit according to the gap size also includes: Once the matching dimension is confirmed to reach the second dimension accuracy, the matching dimension = gap dimension - thickness of the first feeler gauge.

[0015] On the other hand, this application also proposes a feeler gauge tool for the automatic centering assembly method described above, wherein the feeler gauge tool includes a push rod and a standardized feeler gauge kit, the standardized feeler gauge kit containing multiple first feeler gauges of different thicknesses; The push rod includes: a housing, an elastic element, and a push head. The elastic element is disposed inside the housing, and the push head is connected to the elastic element and is movably disposed at one end of the housing. The elastic element applies a spring force to the pusher to insert the selected first feeler gauge into the radial gap between the lens barrel and the lens frame.

[0016] The beneficial effects of the high-precision automatic centering assembly method and feeler gauge tool for lens barrel and frame provided in this application are at least as follows: Through dual-channel precision measurement, the actual radial clearance between the lens barrel and frame can be determined, thereby selecting a first feeler gauge of a predetermined specification. The quickly selected first feeler gauge is symmetrically positioned in the radial clearance at four quadrant positions. Furthermore, based on the four-quadrant multi-directional compensation method, uniform force is applied at multiple positions within the radial clearance to ensure assembly accuracy. The relative position of the frame within the lens barrel is gradually adjusted to achieve predetermined accuracy in the coaxiality and tilt angle between the frame and the lens barrel, realizing micron-level fine-tuning and ensuring that the coaxiality deviation is controlled within 0.01 mm. This improves assembly accuracy, significantly enhances assembly efficiency and consistency, and provides high repeatability. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1A flowchart illustrating the main steps of an automatic centering assembly method for a high-precision lens barrel and frame provided in this application embodiment; Figure 2 A cross-sectional view of the assembled lens barrel and frame, illustrating a high-precision automatic centering assembly method for a lens barrel and frame provided in this application embodiment. Figure 3 This application provides a schematic diagram illustrating the principle of the push rod in an automatic centering assembly method for a high-precision lens barrel and frame, as shown in the embodiments of this application. Figure 3 Figure (a) is a sectional view of the push rod. Figure 3 Figure (b) is a sectional view of the push rod in use; Figure 4 A flowchart illustrating the detailed steps of step S300 in a high-precision automatic centering assembly method for a lens barrel and frame provided in this application embodiment. Figure 5 A cross-sectional view of the synchronous pushing structure in use of an automatic centering assembly method for a high-precision lens barrel and frame provided in this application embodiment; Figure 6 This is a cross-sectional view of the synchronous pushing structure in an automatic centering assembly method for a high-precision lens barrel and frame provided in an embodiment of this application.

[0019] The following are the labeling elements in the figure: 10. Lens tube; 11. Radial clearance; 20. Lens frame; 30. First feeler gauge; 40. Second feeler gauge; 50. Push rod; 510. Housing; 511. Mounting step; 520. Elastic element; 530. Push head; 540. Flexible rubber layer; 541. Circular limiting platform; 542. Hemispherical boss; 543. Pressure step; 60. Synchronous pushing structure; 610. Pushing bracket; 611. Cross-shaped frame; 612. Holding rod; 613. Adjustment slot; 620. Adjustment elastic element; 630. Adjustment block; 631. Mounting hole; 640. Locking element. Detailed Implementation

[0020] To make the technical problems, technical solutions, and beneficial effects to be solved by this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and are not intended to limit the scope of this application.

[0021] It should be noted that when a component is referred to as "fixed to" or "set on" another component, it may be directly or indirectly located on that other component. When a component is referred to as "connected to" another component, it may be directly or indirectly connected to that other component. The terms "upper," "lower," "left," "right," "front," "rear," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate orientations or positions based on the accompanying drawings, and are for ease of description only, and should not be construed as limiting the technical solution. The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features. "A plurality" means two or more, unless otherwise explicitly defined.

[0022] The technical terms used in this embodiment are explained as follows: Optical axis: The optical axis is an imaginary straight line passing through the center of the lens's optical system, usually the most critical axis of symmetry in the lens. It represents the path of light through the lens system, typically from the front to the back of the lens. The optical axis does not necessarily perfectly align with the lens's physical structure, but it is the theoretical center line in the image formation process and a benchmark for optical design. The optical axis is crucial for image quality, and the various optical components of a lens (such as lenses and prisms) are typically aligned around it.

[0023] Mechanical axis: The mechanical axis refers to the axis associated with the actual physical structure of the lens, usually the lens's rotation or alignment axis. It indicates the mechanical symmetry of the lens assembly and may be aligned with the optical axis, but not always.

[0024] During lens manufacturing and assembly, the mechanical axis is typically the reference that ensures the correct alignment of all lens components. In some cases, there may be a deviation between the mechanical axis and the optical axis, which can affect image quality, especially in high-precision optical systems. For example, the lens frame and its optical lenses should ideally align on the optical axis. However, if the mechanical axis of the lens barrel deviates from that of the lens frame during assembly, it will result in a significant coaxiality deviation, making it impossible to guarantee the coaxiality of the optical axis and the mechanical axis.

[0025] Traditional assembly methods, such as the fixed-thickness shim method and the mechanical set screw method, have significant shortcomings when facing micron-level precision requirements. While the fixed-thickness shim method is low-cost, its inability to adjust the thickness necessitates multiple trial fittings, leading to low assembly efficiency. In particular, the inability to adjust the thickness fails to cover different batch tolerance ranges, resulting in poor adaptability. Furthermore, the time-consuming adjustment process hinders rapid mass assembly. Although the mechanical set screw method is adjustable, it relies on manual experience, resulting in low efficiency and poor repeatability due to variations in experience. It also easily scratches optical components during operation, which is detrimental to the production of high-end optical modules. This makes high-precision assembly difficult. Therefore, traditional assembly methods suffer from poor adaptability and difficulty in guaranteeing high precision, especially under micron-level precision requirements, where it is difficult to consistently achieve a gap control accuracy of ≤5μm. Traditional methods cannot meet the high-precision requirements of mass production. Therefore, this application proposes the following embodiments, as detailed below: Please see Figure 1 This embodiment proposes a high-precision automatic centering assembly method for the lens barrel and frame, used to assemble the frame inside the lens barrel and ensure the high precision requirement of coaxiality between the frame and the lens barrel (see [link]). Figure 2 The automatic centering assembly method mainly includes the following steps: Step S100: Determine the radial clearance size between the lens barrel and the lens frame, and select a first feeler gauge of predetermined specifications according to the clearance size.

[0026] Please see Figure 2 In the specific process, a micrometer with a resolution of no less than 1 µm is used to accurately measure the outer diameter of the frame 20 and the inner diameter of the barrel 10, and the gap size of the radial clearance 11 is calculated, where the gap size = 0.5 (outer diameter of the frame - inner diameter of the barrel). The actual assembly clearance is obtained through dual-channel precision measurement to ensure data accuracy.

[0027] Please see Figure 2 Then, based on the gap size, a first feeler gauge 30 is selected from the standardized feeler gauge kit. The thickness of the first feeler gauge 30 is closest to the gap size. The standardized feeler gauge kit contains multiple first feeler gauges of different thicknesses, and the dimensions of each first feeler gauge are pre-calibrated. Therefore, the first feeler gauge can be quickly selected directly based on the calculated gap size, ensuring that the thickness of the first feeler gauge is less than and closest to the gap size.

[0028] To ensure assembly efficiency, the gap size needs to be judged first. If the gap size is within the first size range, it is considered acceptable, and the first feeler gauge is selected. For example, the first size range is 0.005–0.05 mm. If the gap size is greater than 0.05 mm, it is considered too large and is judged as unacceptable. The lens barrel and frame need to be reworked, or this method should not be used for assembly. If the gap size is less than 0.005 mm, assembly can be performed directly, achieving the requirement of controlling the coaxiality deviation within 0.01 mm.

[0029] In addition, to ensure assembly efficiency, the thickness of the selected first feeler gauge also needs to be specified to ensure that the matched dimension meets the second dimensional accuracy. The matched dimension = clearance dimension - thickness of the first feeler gauge. Specifically, the matched dimension ≤ 0.02 mm. Only then can the selected first feeler gauge be considered to meet the assembly requirements, thus ensuring that the coaxiality deviation ≤ 0.01 mm after assembly. Therefore, using a high-precision standard feeler gauge kit to quickly select and match the first feeler gauge to the actual clearance ensures the accuracy of radial clearance control.

[0030] Step S200: Place the lens frame into the inner cavity of the lens tube in sequence, and symmetrically set the first feeler gauge at the four quadrant positions of the radial gap.

[0031] Please see Figure 2 The four quadrant positions are four points (+x, -x, +y, and -y) spaced 90° apart on the circumference. By symmetrically placing the first feeler gauge at the four quadrant positions of the radial clearance, miniature precision first feeler plates (thickness ≤0.01 mm) are symmetrically arranged on the inner wall of the lens barrel, ensuring uniform force distribution and preventing damage to parts during assembly. The symmetrical arrangement of the first feeler gauges at the four quadrant positions ensures uniform force application, avoiding the impact of localized uneven forces on assembly accuracy.

[0032] Please see Figure 2 , Figure 3 In Figure (a), the first feeler gauge 30 can be pushed into the radial gap 11 by the push rod 50. To avoid scratching the optical lens, frame 20, or lens barrel 10 due to hard metal contact, the first feeler gauge 30 is pushed by the push rod 50 during the clamping process. For example, the push rod 50 has a diameter of about 4–8 mm and a length of 10–20 mm.

[0033] Please see Figure 3In Figures (a) and (b), in a push rod 50 structure, the push rod 50 specifically includes a housing 510, an elastic element 520, and a push head 530. The elastic element 520 is disposed inside the housing 510, and the push head 530 is connected to the elastic element 520 and movably disposed at one end of the housing 510. A flexible soft rubber layer 540 is provided on the push head 530. The housing 510 is a cylindrical long tube, and the push head 530 penetrates through the bottom of the housing 510 and can protrude from the bottom. The flexible soft rubber layer 540 is fixed on the protruding end of the push head 530. The flexible soft rubber layer 540 can be a POM / PTFE soft tip. The end of the push head 530 located inside the housing 510 is connected to the elastic element 520. The elastic element 520 can be a metal spring, which provides a stable thrust to the push head 530.

[0034] Please see Figure 3 In Figure (b), the flexible soft rubber layer 540 can be formed as a whole hemisphere or other structures. For example, the flexible soft rubber layer 540 includes a circular limiting platform 541 and a hemispherical protrusion 542 on its end face. The outer diameter of the circular limiting platform 541 is larger than that of the hemispherical protrusion 542. Therefore, a pressure step 543 is formed between the circular limiting platform 541 and the hemispherical protrusion 542. When pressure is applied to the top of the feeler gauge (first feeler gauge 30) by the step, it is first guided by the arc-shaped outer wall of the hemispherical protrusion 542. The feeler gauge (first feeler gauge 30) is guided to the surface of the circular limiting platform 541 of the pressure application step 543. The outer wall of the circular limiting platform 541 can abut against the inner wall of the lens tube 10, while the outer wall of the hemispherical boss 542 blocks the radial inward movement of the feeler gauge (first feeler gauge 30). Thus, when the step abuts against the end face of the feeler gauge to apply pressure, it can ensure that the pressure direction is close to vertical, and apply a relatively stable vertical thrust to the first feeler gauge 30, which is more conducive to inserting the feeler gauge (first feeler gauge 30) into the radial gap 11. It should be noted that the outer diameter of the circular limiting stage 541 can be greater than or equal to the outer diameter of the outer shell 510. When the push rod 50 is in use, the outer shell 510 is attached to the inner wall of the lens barrel 10. At this time, the outer wall of the circular limiting stage 541 is deformed by the pressure of the outer wall of the lens barrel 10. The circular limiting stage 541 can be pushed along the inner wall of the lens barrel 10. The push head 530 can completely cover the radial gap 11, ensuring that the push head 530 can be in stable contact with the feeler gauge (first feeler gauge 30).

[0035] Please see Figure 3In Figure (b), during the assembly of the first feeler gauge, the push rod has a relatively small external dimension, allowing the outer shell to contact the inner wall of the lens barrel. The flexible rubber layer at the bottom contacts the first feeler gauge, and the pressure from the elastic element pushes the first feeler gauge into the radial gap, achieving flexible limiting and stable positioning. Since the insertion of the first feeler gauge is a rapid coarse adjustment process, the push rod can be used to push the first feeler gauge in each of the four quadrants, ultimately ensuring that the lens frame maintains a coaxiality of ≤0.01 mm and a radial gap of ≤0.02 mm within the lens barrel, providing a reliable foundation for subsequent multi-directional compensation and fine adjustment.

[0036] Step S300: Based on the four-quadrant multi-directional compensation method, apply equal preload at multiple positions within the radial gap to gradually adjust the relative position of the lens frame within the lens barrel, so that the coaxiality and tilt angle between the lens frame and the lens barrel reach the predetermined accuracy.

[0037] In practice, the four-quadrant multi-directional compensation method involves adding feeler gauges of a certain thickness at four locations (+x, -x, +y, and -y) to fill the radial gap. Applying feeler gauges of equal thickness at all four locations creates equal preload, gradually adjusting the relative position of the lens frame within the lens barrel. During operation, a second feeler gauge of the same thickness is used simultaneously at all four locations to automatically align the lens frame, and a center deviation measuring instrument is used in real time to check the coaxiality. This step is a fine-tuning process for the lens frame within the lens barrel. After fine-tuning, the predetermined accuracy requirements are: coaxiality between the lens frame and the lens barrel ≤ 0.005 mm, and tilt angle ≤ 30″.

[0038] Please see Figure 1 , Figure 4 The detailed steps of step S300 include steps S310-S330. Specifically, they are as follows: Step S310: Detect the relative position of the lens frame within the inner cavity of the lens barrel.

[0039] In practice, a center deviation measuring instrument is needed to detect coaxiality in real time and determine the relative position of the lens frame in the inner cavity of the lens barrel.

[0040] Step S320: Insert a second feeler gauge of the same thickness into a symmetrical position in the four quadrants of the inner cavity of the endoscope tube according to the relative position, wherein the thickness of the second feeler gauge is less than the thickness of the first feeler gauge.

[0041] Please see Figure 5 , Figure 6In the specific process, based on the real-time detection of the coaxiality, the push rod 50 simultaneously pushes the second feeler gauge 40 at symmetrical positions in the four quadrants. The thickness of the second feeler gauge 40 is less than that of the first feeler gauge 30, so as to apply equal preload at multiple positions, thereby achieving more precise adjustment. To achieve real-time pushing at each position, another synchronous pushing structure 60 can be used. For example, the synchronous pushing structure 60 can synchronously push each push rod 50 at symmetrical positions in the four quadrants, so that the push rod 50 can simultaneously push the second feeler gauge 40 at multiple positions.

[0042] Please see Figure 5 , Figure 6 For example, the specific structure of the synchronous pushing structure 60 includes: a pushing bracket 610, an adjusting elastic element 620, an adjusting block 630, and a locking element 640. The pushing bracket 610 can be a cross-shaped frame 611, with a gripping rod 612 fixedly installed in the middle of the cross-shaped frame 611. Multiple adjusting slots 613 are arranged radially on the pushing bracket 610. The adjusting block 630 is located in the adjusting slot 613 and moves radially. The adjusting block 630 has a mounting hole 631, and the aforementioned push rod 50 can be installed through the mounting hole 631. In this way, by adjusting the position of the adjusting block 630 from the gripping rod 612, the distance between each push rod 50 can be adjusted. Thus, the position between the four push rods 50 can be adaptively adjusted according to different inner diameter sizes of the lens barrel 10, making it suitable for different specifications of lens barrel 10.

[0043] Please see Figure 5 , Figure 6 The adjusting elastic element 620 can be a spring, and the locking element 640 can be a set screw. The adjusting elastic element 620 is disposed in the adjusting slot 613 and connected to the adjusting block 630, applying a spring force to the adjusting block 630 away from the gripping rod 612 (central axis). In use, the adjusting block 630 is pushed towards the central axis according to the specifications of the lens barrel 10. When the push rod 50 is inserted into the lens barrel 10 and abuts against the inner wall of the lens barrel 10, the push rod 50 has a radial spring force under the action of the adjusting elastic element 620, thus being able to stably abut against the inner wall of the lens barrel 10. The locking element 640 can lock the position of the adjusting block 630 in the push bracket 610. When all four push rods 50 at the four quadrant points are pressed into the lens barrel 10, the position of each push rod 50 is locked by tightening the set screw, making it difficult for them to shift. Furthermore, to facilitate the positioning and installation of the push rod 50 and the adjusting block 630, an installation step 511 is provided on the outer wall of the push rod 50. The installation step 511 abuts against the installation hole 631, ensuring that the height of each push rod 50 is consistent after installation and guaranteeing the stability of synchronous force application.

[0044] Under the real-time detection of the center deviation measuring instrument, micron-level fine adjustment is achieved through synchronous compensation of multi-directional gaps, ensuring that the coaxiality accuracy of the lens frame and lens barrel reaches within 0.01 mm, or even ≤ 0.005 mm.

[0045] Step S330: Repeat steps S310-S320 until the coaxiality and tilt angle of the lens frame and lens barrel reach the predetermined accuracy.

[0046] In the specific process, the push rod is used to push the second feeler gauge simultaneously at the symmetrical positions in the four quadrants. During the fine adjustment process, the second feeler gauge at each position is pushed into the radial gap synchronously, ensuring the accuracy of the center deviation measuring instrument in real-time detection of coaxiality. This makes it easier to determine the relative position of the lens frame in the inner cavity of the lens barrel and improves assembly efficiency.

[0047] It should be noted that during the synchronous advancement of the second feeler gauge to the radial clearance, the center deviation measuring instrument continuously monitors the coaxiality. It's possible that only one point among the four positions (+x, -x, +y, and -y) shows a deviation in direction; this deviation is the residual deviation. Therefore, when a residual deviation is detected between the lens barrel and frame, its direction and magnitude are determined. Based on the magnitude of the residual deviation, a third feeler gauge is then used. The thickness of the third feeler gauge is less than that of the first feeler gauge; this smaller thickness allows for more precise local adjustments. Therefore, based on the direction of the residual deviation, a third feeler gauge is added or removed at the corresponding quadrant point of the radial gap to ensure that the coaxiality and tilt angle of the lens frame and lens barrel reach the predetermined accuracy. If residual deviation exists, iterative correction can be performed by gradually increasing or decreasing the thickness of a single feeler gauge until the quality requirements of coaxiality between the lens frame and lens barrel ≤ 0.005 mm and tilt angle ≤ 30″ are met.

[0048] This embodiment presents a high-precision automatic centering assembly method for the lens barrel and frame. The frame is centered and assembled into the lens barrel. Through micron-level radial clearance control combined with a fine-tuning process, the optical axis of the frame is stabilized, achieving high-precision installation of the lens barrel and frame. The assembly clearance control accuracy is ≤5μm; coaxiality deviation: ≤0.01mm; and assembly repeatability error: <3μm. Standardized processes and symmetrical force application structures reduce human error, thereby improving operational repeatability and facilitating production standardization. The assembly and adjustment time for a single operation is reduced to less than 15 minutes, improving lens assembly efficiency. It is adaptable to different batch tolerance combinations and materials, offering wide compatibility. The use of standardized feeler gauges reduces manufacturing and maintenance costs.

[0049] This application also proposes a feeler gauge tool for the automatic centering assembly method described above, wherein the feeler gauge tool includes a push rod and a standardized feeler gauge kit, the standardized feeler gauge kit containing multiple first feeler gauges of different thicknesses.

[0050] The push rod, as described above, includes, for example, a housing, an elastic element, and a push head. The elastic element is disposed within the housing, and the push head is connected to the elastic element and movably disposed at one end of the housing. The elastic element applies a spring force to the push head to insert the selected first feeler gauge into the radial gap between the lens barrel and the lens frame.

[0051] In summary, this application provides a high-precision automatic centering assembly method and feeler gauge tool for lens barrel and frame. Through dual-channel precision measurement, the actual radial clearance between the lens barrel and frame can be determined, allowing for the selection of a first feeler gauge of a predetermined specification. This first feeler gauge is quickly and symmetrically positioned in the radial clearance across four quadrants. Furthermore, based on a four-quadrant multi-directional compensation method, uniform force is applied at multiple locations within the radial clearance to ensure assembly accuracy. The relative position of the frame within the lens barrel is gradually adjusted to achieve predetermined accuracy in coaxiality and tilt angle between the frame and barrel, enabling micron-level fine-tuning and ensuring coaxiality deviation is controlled within 0.01 mm. This improves assembly accuracy, significantly enhances assembly efficiency and consistency, and provides high repeatability.

[0052] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A high-precision automatic centering assembly method for a lens barrel and frame, used to assemble the lens frame inside the lens barrel, characterized in that, The automatic centering assembly method includes the following steps: Determine the radial clearance size between the lens barrel and the lens frame, and select a first feeler gauge of predetermined specifications according to the clearance size; The lens frame is placed into the inner cavity of the lens tube in sequence, and the first feeler gauge is symmetrically set at the four quadrant positions of the radial gap; Based on the four-quadrant multi-directional compensation method, equal preload is applied at multiple positions within the radial gap to gradually adjust the relative position of the lens frame within the lens barrel, so that the coaxiality and tilt angle of the lens frame and the lens barrel reach a predetermined accuracy.

2. The high-precision automatic centering assembly method for the lens barrel and frame as described in claim 1, characterized in that, The step of applying equal preload at multiple locations within the radial gap to gradually adjust the relative position of the lens frame within the lens barrel, based on the four-quadrant multi-directional compensation method, includes: The relative position of the test frame within the inner cavity of the test tube is detected; According to the relative position, a second feeler gauge of the same thickness is inserted into the four quadrants symmetrically in the inner cavity of the lens barrel, wherein the thickness of the second feeler gauge is less than the thickness of the first feeler gauge. Repeat the above steps of "detecting the relative position of the lens frame in the inner cavity of the lens barrel" and "inserting a second feeler gauge of the same thickness into the four quadrants of the inner cavity of the lens barrel according to the relative position" until the coaxiality and tilt angle of the lens frame and the lens barrel reach the predetermined accuracy.

3. The high-precision automatic centering assembly method for the lens barrel and frame as described in claim 2, characterized in that, In the step of inserting a second feeler gauge of the same thickness into the four quadrants symmetrically positioned within the inner cavity of the endoscope tube according to the relative position: The second feeler gauge is pushed simultaneously at symmetrical positions in the four quadrants by the push rod, so as to apply equal preload at multiple positions.

4. The high-precision automatic centering assembly method for the lens barrel and frame as described in claim 2, characterized in that, In the step of detecting the relative position of the lens frame within the inner cavity of the lens barrel: When a residual deviation is detected between the lens barrel and the lens frame, determine the direction and magnitude of the residual deviation; The third feeler gauge is determined based on the magnitude of the residual deviation, wherein the thickness of the third feeler gauge is less than the thickness of the first feeler gauge; According to the direction of the residual deviation, the third feeler gauge is added or reduced at the corresponding quadrant point of the radial gap to ensure that the coaxiality and tilt angle of the lens frame and the lens barrel reach the predetermined accuracy.

5. The high-precision automatic centering assembly method for the lens barrel and frame as described in claim 1, characterized in that, In the step of sequentially placing the lens frame into the inner cavity of the lens barrel and symmetrically setting the first feeler gauge at the four quadrant positions of the radial gap: The first feeler gauge is pushed into the radial gap using a push rod.

6. The high-precision automatic centering assembly method for the lens barrel and frame as described in claim 5, characterized in that, In the step of pushing the first feeler gauge into the radial gap by means of a push rod, the push rod includes a housing, an elastic element and a push head, the elastic element is disposed in the housing, and the push head is connected to the elastic element and movably disposed at one end of the housing; The pusher head is provided with a flexible soft rubber layer.

7. The high-precision automatic centering assembly method for the lens barrel and frame as described in claim 6, characterized in that, In the step of pushing the first feeler gauge into the radial clearance using a push rod: The first feeler gauge is pushed into the radial gap by the pressure of the elastic element through the flexible rubber layer at one end of the push rod.

8. The high-precision automatic centering assembly method for the lens barrel and frame as described in claim 1, characterized in that, In the step of determining the radial clearance size between the lens barrel and the lens frame, and selecting a first feeler gauge of predetermined specifications according to the clearance size: The outer diameter of the frame and the inner diameter of the lens barrel are precisely measured using a micrometer, and the radial clearance is calculated, where the clearance is 0.5 (outer diameter of the frame - inner diameter of the lens barrel). Select a first feeler gauge from a standardized feeler gauge kit based on the gap size, wherein the thickness of the first feeler gauge is closest to the gap size.

9. The high-precision automatic centering assembly method for the lens barrel and frame as described in claim 8, characterized in that, The step of calculating the radial clearance dimension by accurately measuring the outer diameter of the frame and the inner diameter of the lens barrel using a micrometer further includes: The gap size is determined to be within a first size range; The step of selecting the first feeler gauge from the feeler gauge kit according to the gap size further includes: Once the matching dimension is determined to reach the second dimensional accuracy, the matching dimension = gap dimension - thickness of the first feeler gauge.

10. A feeler gauge tool for use in the automatic centering assembly method as described in any one of claims 1-9, characterized in that, The feeler gauge tool includes a push rod and a standardized feeler gauge kit, the standardized feeler gauge kit containing multiple first feeler gauges of different thicknesses; The push rod includes: a housing, an elastic element, and a push head. The elastic element is disposed inside the housing, and the push head is connected to the elastic element and movably disposed at one end of the housing. The elastic element applies a spring force to the pusher to insert the selected first feeler gauge into the radial gap between the lens barrel and the lens frame.

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