Cam Gear Driving Apparatus for Mirror Unit Alignment
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Solution Overview
Problem
Existing driving apparatuses for mirror units in single-lens reflex cameras face challenges in ensuring smooth movement of followers due to potential catching by cam gear level differences, and they often increase component count and size with additional stopper structures.
Innovation Solution
The apparatus employs a first and second gear with cam portions that act on followers in radial and thrust directions, ensuring smooth radial movement and utilizing a minimal component stopper structure by optimizing cam lift amounts to prevent dropping and maintain alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the operation angle of the lever becomes large, then the lever can achieve a wider range of motion, but the bearing member cannot overlap the two cam gears in the shaft direction at all times, causing the bearing member to be caught by a difference in level between the two cam gears and the operation of the lever is disturbed
Solution Approach 1:
The patent introduces a stopper ring that extends in the shaft direction (a different dimension from the radial cam interaction) to prevent the bearing member from dropping out. This dimensional extension allows the bearing member to maintain proper alignment with the cam gears even when the lever operates at large angles, preventing catching by level differences while preserving the wide operation range.
Solution Approach 2:
The stopper ring acts as an intermediary element between the bearing member and the cam gears. It mediates the potential conflict between large operation angles and smooth operation by providing a physical barrier that prevents the bearing member from dropping out, thereby ensuring continuous reliable operation without restricting the lever's motion range.
2Reliability
If a stopper ring is used as a drop-out stopper of the bearing member, then the bearing member is prevented from dropping out, but the number of components increases and the size in the shaft direction increases
Solution Approach 1:
The stopper ring is merged with the bearing member as an integrated component rather than being a separate assembly. The stopper ring is formed as a single piece with the bearing member, eliminating the need for additional fasteners or mounting structures. This merging reduces the number of components while maintaining the drop-out prevention function.
Solution Approach 2:
The stopper ring serves multiple functions: it prevents the bearing member from dropping out, maintains proper alignment with the cam gears during large-angle operations, and integrates with the bearing member structure. This multi-functionality reduces the need for separate components, thereby reducing overall device complexity.
3Reliability
If a stopper ring is used as a drop-out stopper of the bearing member, then the bearing member is prevented from dropping out, but the size in the shaft direction increases
Solution Approach 1:
The stopper ring is designed with localized functionality - it extends only in the specific region where drop-out prevention is needed, rather than uniformly increasing the size of the entire bearing member. The stopper portion is concentrated where it is most effective, minimizing the overall size increase in the shaft direction while maintaining reliable drop-out prevention.
Data Source
AI summary
A driving apparatus which is capable of smoothly moving a follower by a cam portion, and realizes the stopper structure of the follower by a small number of components without the size increased. The driving apparatus comprises an up cam gear having an up radial cam and an up thrust cam, and a down cam gear unit having a down radial cam and a down thrust cam. The up cam gear and the down cam gear unit mesh with each other in a vicinity of a region in which a lift amount of the up radial cam with respect to the follower increases. In a vicinity of a position at which the up cam gear and the down cam gear unit mesh with each other, a lift amount of the up thrust cam is larger than a lift amount of the down thrust cam in the thrust direction.