Lens Barrel Frame Structure for Cutout Rigidity and Deformation Control
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Solution Overview
Problem
Conventional lens barrels with cutouts in the outer peripheral surface for avoiding interference with components suffer from reduced strength and deformation susceptibility, particularly around the biasing pin, leading to potential deformation of the entire lens frame.
Innovation Solution
A lens barrel design featuring a lens frame with cam pins, a biasing pin, a cutout portion, a rectilinear guide tube, and rectilinear guide portions, ensuring continuous rigidity from the biasing pin to the cam pins, supported by a compression coil spring to maintain structural integrity despite the cutout.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a part of the outer peripheral surface of the lens holding frame is cut out in the optical axis direction to avoid interference with lens barrel components, then the space for component arrangement is improved, but the strength of the lens holding frame is reduced and deformation susceptibility increases
Solution Approach 1:
The lens holding frame is segmented into a substantially cylindrical main body portion and a flange portion, with the cutout located in the main body portion. This segmentation allows the cutout to be positioned strategically without compromising the overall structural integrity, as the flange portion and continuous main body provide sufficient strength while the cutout enables component arrangement.
Solution Approach 2:
The cutout is positioned at a specific location in the main body portion where it causes minimal impact on overall strength. The continuous provision of the main body portion from the biasing pin to the first cam pins ensures that critical areas maintain full strength while the cutout provides necessary space in less critical regions.
2Strength
If the lens holding frame is made continuously in the circumferential direction to maintain strength, then the strength is improved, but the space for component arrangement is reduced
Solution Approach 1:
The frame is divided into functional zones: the continuous main body portion provides strength and houses the optical system, while the cutout in the main body portion and the flange portion provide space for component arrangement. This segmentation allows both strength and space requirements to be satisfied simultaneously.
Solution Approach 2:
The flange portion extends radially outward from the main body portion, utilizing the radial dimension to provide additional space for component arrangement without compromising the circumferential continuity and strength of the main body portion. This dimensional extension solves the space constraint while maintaining structural integrity.
3Stability of the object's composition
If a biasing pin is provided to suppress looseness, then the stability is improved, but the risk of entire lens frame deformation increases due to reaction force from cam groove
Solution Approach 1:
The cam groove acts as an intermediary that distributes the reaction force from the biasing pin across a broader area of the lens holding frame. By engaging the biasing pin with the cam groove, the localized force is transformed into a distributed stress pattern, reducing the risk of deformation while maintaining stability against looseness.
Solution Approach 2:
The continuous provision of the main body portion from the biasing pin to the first cam pins changes the structural parameter of rigidity in the critical path. This continuous structure increases the moment of inertia and reduces flexibility in the area subjected to reaction forces, thereby preventing deformation while maintaining the biasing function.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The design maintains the strength of the lens frame and prevents deformation, even with a partial cutout, by distributing the biasing force effectively and supporting the frame with rectilinear guide grooves, enhancing durability.
Implementation Method 1
a biasing pin supported so as to be biased in a radial direction centered on an optical axis of the lens
Data Source
AI summary
A lens barrel 10 comprises a fourth lens group unit 20, cam pins 22a and 22b, a biasing pin 23, a cutout portion C1, a substantially cylindrical first lens group unit 13, and a plurality of rectilinear guide portions 25. The fourth lens group unit 20 has a substantially cylindrical main body portion 21 that holds a lens L4a, etc. The cam pins 22a and 22b are provided to the fourth lens group unit 20, protrude in the radial direction, and engage in the cam grooves 14b of the cam frame 14. The biasing pin 23 is provided to the fourth lens group unit 20, is supported so as to bias in the radial direction, and engages in the cam groove 14b. The cutout portion C1 is formed by cutting out the portion of the main body portion 21 of the fourth lens group unit 20 opposite the biasing pin 23 in the direction of the optical axis. The main body portion 21 of the fourth lens group unit 20 is provided continuously in the circumferential direction, from the biasing pin 23 to the cam pins 22a and 22b.