Vehicle Seat Fitting With Radial Planet Gear Locking for Backrest Range
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Solution Overview
Problem
Existing vehicle seat backrest adjusters lack a high-strength, continuously adjustable mechanism that can be motorized and provide fast adjustment speeds, especially for electrified rear seats requiring a large adjustment range from horizontal forward to horizontal rear positions.
Innovation Solution
A fitting with a planetary gear train featuring ring gears and planet gears, where interlocking planet gears are radially displaceable and retained by a guideway, allowing for selective locking and unlocking to achieve smooth, efficient adjustment between ring gears, and utilizing an eccentric contour for control and energy storage to manage play and load.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a conventional articulated fitting with outer gears and planet gears is used for backrest adjustment, then the adjustment mechanism can be implemented, but the adjustment movement is slanted rather than concentric and the load-bearing capability is insufficient for high-strength applications
Solution Approach 1:
The fitting is divided into two functionally independent planetary gear sets: a first planetary gear set (with first planet gears 140 and first interlocking planet gears 150) for load-bearing and a second planetary gear set (with second planet gears 140 and second interlocking planet gears 150) for adjustment movement. This segmentation allows each subsystem to be optimized for its specific function, resolving the contradiction between strength and movement quality
Solution Approach 2:
The planet carrier 160 serves as an intermediary component that connects both planetary gear sets and transmits forces between them. By using the planet carrier as a mediator, the patent achieves both high load-bearing capability through the first planetary gear set and proper concentric adjustment movement through the second planetary gear set, eliminating the slanted movement problem of conventional fittings
2Productivity
If the fitting is designed for continuous infinite adjustment with motorized drive, then fast adjustment speeds are achieved, but the mechanism complexity increases
Solution Approach 1:
Both planetary gear sets share common components including the planet carrier 160, ring gears 112/122, and gear toothing 114/124. This multi-functionality allows a single motorized drive can continuously rotate the planet carrier to achieve infinite adjustment positions, while the shared structure reduces overall complexity despite the enhanced functionality
Solution Approach 2:
The interlocking planet gears 150 are designed with variable spacing from the rotation axis, allowing selective engagement between locked and unlocked states. This dynamic capability enables the fitting to switch between fixed positioning and continuous adjustment modes, achieving fast motorized adjustment while maintaining structural efficiency
3Adaptability or versatility
If interlocking planet gears with variable spacing are used for selective locking, then the fitting can be locked and unlocked, but the device complexity increases
Solution Approach 1:
Each interlocking planet gear 150 combines two gear wheels 152/154 with different tooth counts into a single rotating component. This merging allows the interlocking planet gear to simultaneously engage with both ring gears 112/122, achieving selective locking capability while reducing the number of separate components and simplifying the overall structure
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 solution enables high-strength, continuous, and fast adjustment of vehicle seat backrests, suitable for electrified rear seats with extended adjustment ranges, ensuring high load-bearing capability while minimizing installation space and weight.
Implementation Method 1
at least one planet gear which is mounted on a planet carrier so as to be rotatable eccentrically to the axis and meshes with the first ring gear toothing and the second ring gear toothing, wherein by rotating the planet carrier about the axis the at least one planet gear is able to roll in the first ring gear toothing and in the second ring gear toothing
Data Source
AI summary
A fitting for a vehicle seat may have a first ring gear having first ring gear teeth, a second ring gear having second ring gear teeth, and a planet gear mounted on a planet carrier and which meshes with the first and second ring gear teeth. A blocking planet gear, which can be rotated about a blocking-planet-gear axis of rotation, permanently meshes with the first ring gear teeth and with the second ring gear teeth, and the distance between the blocking-planet-gear axis of rotation and the axis can be changed so that the blocking planet gear can be transferred selectively between locking meshing and non-locking meshing with the first ring gear teeth and/or with the second ring gear teeth. A vehicle seat having a seat part, a backrest and a fitting of this type for setting an angle of inclination of the backrest is provided.