Lens Barrel Spring Retention Mechanism for Backlash Control
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Solution Overview
Problem
Existing lens barrel mechanisms using coil springs to suppress backlash between cams and cam followers face issues where the coil spring end face can come off, potentially intruding into the optical path, and direct bonding complicates cam follower attachment and lens barrel maintenance.
Innovation Solution
A lens barrel design featuring a fixed barrel with rotatable cam rings and moving lens barrels, using an elastic member between them to bias the barrels in opposite directions, with an edge regulating mechanism to prevent the coil spring from coming off and allowing easy maintenance by not bonding it to the moving parts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the coil spring is directly bonded to the moving lens barrel, then the coil spring end face is prevented from coming off, but the cam follower attachment becomes difficult due to spring force
Solution Approach 1:
The patent introduces a spring retaining structure (groove and retaining rim) as an intermediary between the coil spring and the moving lens barrel. This mediator structure holds the spring in place without requiring direct bonding, thereby preventing spring end face detachment while eliminating the spring force interference during cam follower attachment operations.
2Reliability
If the coil spring is directly bonded to the lens barrel unit, then the coil spring end face is prevented from coming off, but the lens barrel unit maintenance becomes difficult
Solution Approach 1:
The spring retaining structure serves as an intermediary that decouples the coil spring from the lens barrel unit. This allows the lens barrel unit to be detached and maintained independently while the spring remains retained by the retaining structure, significantly improving maintenance accessibility.
Solution Approach 2:
The patent segments the spring retention function from the lens barrel unit by introducing a separate retaining structure. This segmentation allows the lens barrel unit to be independently removed for maintenance while the spring remains secured, enabling easy repair and maintenance operations.
3Ease of manufacture
If no bonding is used for the coil spring, then the cam follower attachment is easy, but the coil spring end face may come off and intrude into the optical path
Solution Approach 1:
The spring retaining structure acts as an intermediary constraint that prevents the coil spring end face from moving freely. This mediator structure eliminates the harmful effect of spring end face intrusion into the optical path while maintaining the simplicity of non-bonded spring installation.
Solution Approach 2:
The retaining structure provides preliminary constraint on the coil spring position before any potential harmful movement can occur. By pre-preventing the spring end face from detaching and moving into the optical path, the design proactively eliminates the harmful effect without requiring bonding.
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
This design effectively prevents coil spring detachment and improves maintenance workability while suppressing backlash between cam and cam followers, ensuring stable optical performance.
Implementation Method 1
an elastic member disposed between the first moving lens barrel and the second moving lens barrel in a state where the lens barrel submodule is fixed to the first moving lens barrel, and configured to bias the first moving lens barrel and the second moving lens barrel in mutually opposite directions along the direction of the optical axis
Data Source
AI summary
A lens barrel includes: fixed barrel including straight groove extending in optical axis direction; cam ring rotatable around optical axis relative to the fixed barrel, and provided with first and second cam grooves; first barrel to which sub-barrel to hold first optic is detachably fixed, the first barrel including first cam follower slidably contacting with the straight groove and the first cam groove; second barrel holding second optic, and including second cam follower slidably contacting with the straight groove and the second cam groove; elastic member disposed between the first and second barrels when sub-barrel is fixed to the first barrel, and biasing the first and second barrels oppositely in the optical axis direction; and regulating mechanism regulating position of end of the elastic member relative to the first barrel without fixing the elastic member to the sub-barrel when the sub-barrel is fixed to the first barrel.