Gearing device for seat
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Solution Overview
Problem
The existing gearing devices for seats, such as those described in Japanese Patent No. 4645315, suffer from increased frictional resistance due to load displacement, which can lead to operation failures as the eccentric camshaft tilts, concentrating loads and causing frictional issues.
Innovation Solution
A gearing device configuration featuring a first internally toothed gear with protruding teeth, a second internally toothed gear sharing the same rotation center axis, an externally toothed gear with fewer teeth, and an eccentric member that rotates the externally toothed gear, ensuring most loads are absorbed by the first internally toothed gear, thereby minimizing tilting moments and preventing operation failures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the externally toothed gear meshes with both internally toothed gears while being interposed therebetween, then the gearing device can transmit rotational force, but the loads applied to the internally toothed gears and externally toothed gear cause the eccentric camshaft to tilt, increasing frictional resistance and leading to operation failure
Solution Approach 1:
The patent divides the load-bearing function into two parts: the first internally toothed gear receives most of the loads applied to the gearing device, while the second internally toothed gear is rotatably supported by the first. This segmentation prevents load concentration on the eccentric camshaft, reducing tilting moments and frictional resistance, thereby improving operation reliability
Solution Approach 2:
The first internally toothed gear acts as an intermediary between the external load and the second internally toothed gear. It receives most of the loads and supports the second internally toothed gear, preventing direct transmission of loads to the eccentric camshaft and reducing tilting moments that cause frictional resistance
2Reliability
If the eccentric camshaft rotates the externally toothed gear, then the rotational motion can be transmitted, but the loads tend to be concentrated on a particular portion, increasing frictional resistance and causing operation failure
Solution Approach 1:
The patent segments the load distribution by having the first internally toothed gear receive most of the loads, preventing concentration on a particular portion of the eccentric camshaft. This reduces frictional resistance and improves ease of operation while maintaining reliability
Solution Approach 2:
The patent changes the load distribution parameter by designing the first internally toothed gear to receive most of the loads, altering how forces are transmitted through the system. This parameter change reduces frictional resistance and prevents operation failure
Data Source
AI summary
Disclosed is a gearing device for a seat including a first internally toothed gear, a second internally toothed gear, an externally toothed gear, and an eccentric member. The first internally toothed gear includes a rotation center axis. The second internally toothed gear has the rotation center axis in common with the first internally toothed gear and is rotatably supported by the first internally toothed gear. The externally toothed gear is arranged to an inner side of the first and the second internally toothed gear, to thereby mesh with the first and the second internally toothed gears. The eccentric member rotates the externally toothed gear such that a rotation center thereof follows a path around the rotation center axis, rotatably supports the externally toothed gear about the rotation center, and rotates about the rotation center axis in response to a rotational force being externally input thereto.