Anti-backdrive Disc Recliner Lock Plate Mechanism
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Solution Overview
Problem
Existing continuous disc recliners in automotive vehicles suffer from back-driving, where external loads cause unwanted reclining of the seat back due to insufficient friction, leading to instability in maintaining desired reclined seating positions.
Innovation Solution
Incorporation of an anti-backdrive mechanism featuring a lock anchor, lock plate, and cam system that allows controlled rotation of wedges and engagement with inner teeth to prevent unwanted movement, ensuring the seat back remains in the desired position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If friction between toothed profiles and wedges is used to maintain seat back position, then the structure remains simple, but back-driving occurs under external loads
Solution Approach 1:
A lock plate is introduced as an intermediary component between the cam mechanism and the toothed inner profile. The lock plate engages with the inner teeth to provide a direct mechanical locking action that prevents back-driving, while the cam mechanism remains responsible for actuation. This intermediary element resolves the contradiction by adding positional reliability without requiring complete redesign of the existing simple cam-wedge system.
2Ease of operation
If cam mechanism is used to drive wedges for reclining, then adjustment is smooth and continuous, but unwanted rotation occurs under external load
Solution Approach 1:
The lock plate is designed to dynamically engage and disengage based on cam position. During active adjustment, the cam pushes the lock plate away from the inner teeth, allowing free rotation for smooth reclining. When the cam is released, the lock plate automatically engages with the inner teeth to prevent back-driving. This dynamic behavior resolves the contradiction between ease of operation and position maintenance reliability.
3Reliability
If friction alone maintains reclined position, then the system remains simple, but external loads overcome friction causing back-driving
Solution Approach 1:
The positioning function is segmented into two distinct mechanisms: the cam-wedge system handles active adjustment and positioning, while the lock plate handles passive position maintenance and back-driving prevention. This segmentation allows each component to be optimized for its specific function, providing reliable load resistance without requiring the entire system to be overly complex.
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 anti-backdrive mechanism effectively prevents back-driving by locking the disc recliner in place, maintaining the seat back's reclined position even under external loads, enhancing user comfort and stability.
Implementation Method 1
The seat back is maintained in a desired reclined seating position due to friction between the toothed outer profile and the toothed inner profile at the engagement point and due to friction between the wedges and the fixed and movable plates
Implementation Method 2
The drive mechanism includes a cam and a pair of wedges that define an eccentric, which presses the toothed outer profile and the toothed inner profile into each other at an engagement point defined by the eccentricity
Data Source
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AI summary
A disc recliner includes a fixed plate having a plurality of outer teeth and a movable plate having a plurality of inner teeth meshingly engageable with the outer teeth to allow rolling movement of the movable plate relative to the fixed plate. A pair of wedges defining an eccentric is rotatably mounted between the fixed and movable plates and rotation of the wedges causes the rolling movement of the movable plate. An anchor is disposed between the wedges for rotation therewith. A lock plate is coupled to the anchor and is movable between a locked position engaged with the fixed plate to prevent rotation of the wedges and an unlocked position disengaged with the fixed plate to permit rotation of the wedges. A cam actuates the lock plate from the locked position to the unlocked position and rotates the wedges thereby causing the rolling movement of the movable plate.