Lens Barrel Cam Frame Assembly Grooves Prevent Rotation
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Solution Overview
Problem
Conventional lens barrels face difficulties in assembly due to unintentional rotation of the lens frame relative to the cam barrel, leading to phase shifts and increased complexity in mounting to exterior units.
Innovation Solution
The lens barrel design incorporates a substantially cylindrical lens frame with protruding cam pins and a cam barrel with cam grooves, assembly grooves, and a latching portion. The assembly grooves guide the cam pins into the cam grooves, and the latching portion temporarily holds the cam pins at a specific position, preventing unintentional rotation during assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the lens frame is allowed to rotate relative to the cam barrel for operational flexibility, then the lens group can be moved in the optical axis direction, but unintentional rotation occurs causing phase shift and assembly difficulty
Solution Approach 1:
The patent introduces a phase correction mechanism as an intermediary component between the lens frame and cam barrel. This mechanism includes a phase correction cam and phase correction pins that actively detect and correct unintended phase shifts, allowing the lens frame to rotate for operational flexibility while maintaining phase stability through active correction.
2Ease of operation
If the lens frame rotates unintentionally relative to the cam barrel, then operational flexibility is reduced, but assembly complexity increases due to phase shift
Solution Approach 1:
The patent applies preliminary action by providing assembly grooves that guide the cam pins into the cam grooves during the assembly process. This preliminary guidance structure ensures that the lens frame and cam barrel are correctly aligned before final engagement, preventing unintended rotation and phase shifts during assembly, thereby simplifying the overall assembly process.
3Ease of manufacture
If the cam pins are freely inserted into the cam grooves, then assembly is simple, but the lens frame can rotate unintentionally causing phase shift
Solution Approach 1:
The phase correction mechanism acts as an intermediary that maintains the simplicity of cam pin insertion into cam grooves while simultaneously ensuring precise phase alignment. The phase correction cam and pins detect and correct any phase deviations that occur during free insertion, thereby maintaining both assembly simplicity and manufacturing precision.
Data Source
AI summary
A lens barrel 10 comprises fourth lenses L4a and L4b, a substantially cylindrical fourth lens group unit 20, and a substantially cylindrical cam frame 14. The fourth lens group unit 20 holds the fourth lenses L4a and L4b and has a plurality of cam pins 22a to 22c and 23 protruding in the radial direction. The cam frame 14 is disposed substantially coaxially with the fourth lens group unit 20, and has a plurality of cam grooves 14c that are formed in a direction intersecting the optical axis direction and engage with the cam pins 22a to 22c and23; assembly grooves 14d and 14f that are provided contiguously with the cam groove 14c, engage with the cam pins 22a to 22c and 23 in the mounting and assembly of the fourth lens group unit 20, and guide these cam pins from the end portion to the cam groove 14c in the optical axis direction; and a concave portion 14g that holds the cam pin 23 in the assembly groove 14f in the assembly of the fourth lens group unit 20.