Recliner Mechanism Backdriving Feature
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Solution Overview
Problem
Conventional round-recliner mechanisms in seat assemblies can suffer damage when excessive force is applied to the seatback, causing the pawls' posts to shear and preventing proper engagement with the control ring, leading to operational issues.
Innovation Solution
An adjustment mechanism with a cam-supported pawl system that moves between locked, unlocked, and intermediate positions, featuring a control ring with a recess to receive the pawl post in locked and intermediate states, preventing engagement and thus protecting the post from damage during rapid force application.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the pawl is moved quickly from the locked state to the unlocked state, then the adjustment mechanism responds faster to user input, but excessive force is applied to the post which may cause it to shear
Solution Approach 1:
The control ring includes a recess that receives the post when the pawl is in the unlocked state. This recess acts as a cushioning feature that absorbs the impact and reduces the force transmitted to the post during rapid transitions, preventing the post from shearing while still allowing quick response to user input.
2Reliability
If the post is continuously engaged with the control ring during movement, then the mechanism maintains constant control, but excessive force is applied to the post causing damage
Solution Approach 1:
The control ring is segmented into different regions: an inner surface for when the pawl is locked, a recess for when the pawl is unlocked, and a transition zone. This segmentation allows the post to disengage from the control ring during movement, maintaining control reliability while reducing force on the post to prevent damage.
3Device complexity
If the pawl design includes a post for control ring engagement, then the locking mechanism is simplified, but the post may be sheared from the pawl under excessive force
Solution Approach 1:
The recess in the control ring is designed to receive the post when the pawl is in the unlocked state, providing cushioning that prevents excessive force from being transmitted to the post. This maintains the simple post-based engagement design while improving reliability by preventing post shearing under load.
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 mechanism effectively prevents damage to the pawl posts by allowing the cam to backdrive and disengaging the pawls from the gear plate teeth, maintaining the locking mechanism in an unlocked state and enabling smooth seatback rotation without shearing the posts.
Implementation Method 1
a cam rotatably supported between the first plate and the second plate that moves the pawl between the locked position, the unlocked position, and an intermediate position
Implementation Method 2
The second series teeth are in meshed engagement with the first series of teeth when the pawl is in the locked position to restrict relative rotation between the first plate and the second plate
Implementation Method 3
a control ring having an inner surface slidably receiving the post when the pawl is in the unlocked position and a recess receiving the post when the pawl is in the locked position and when the pawl is in the intermediate position
Data Source
AI summary
An adjustment mechanism includes a first plate, a second plate having first teeth, and a locking mechanism including a pawl having a post and second teeth. The pawl is movable between a locked position, an unlocked position, and an intermediate position between the locked position and the unlocked position. The second teeth are in engagement with the first teeth when the pawl is in the locked position and are disengaged from the first teeth in the unlocked position and in the intermediate position. A cam is rotatably supported between the plates and moves the pawl between the locked position, the unlocked position, and the intermediate position. A control ring has an inner surface that slidably receives the post when the pawl is in the unlocked position and a recess that receives the post when the pawl is in the locked position or the intermediate position.