Oblique Divisional Pawl Locking Device for Vehicle Seats
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Solution Overview
Problem
Conventional locking devices for vehicle seats, such as reclining devices, experience looseness and reduced lock strength due to backlash caused by clearances between the pawl and guide walls, leading to ineffective load transfer and potential disengagement under rotational loads.
Innovation Solution
A locking device with a pawl divided into two obliquely contacting divisional pawls, guided by inclined and vertical surfaces, which are pressed against guide walls to maintain meshed engagement without looseness, allowing straight load transfer and enhanced lock strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the pawl is obliquely divided into two pawl portions to clear clearances between the pawl and guide walls, then meshing engagement between the pawl and gear is improved, but the load in the rotating direction cannot be properly applied to the guide walls and excessive load is applied to the cam
Solution Approach 1:
The pawl is divided into a first pawl portion and a second pawl portion that can move relative to each other in the rotating direction. This segmentation allows the clearances between the pawl and guide walls to be cleared while maintaining proper load distribution to the guide walls through the toothed surfaces of both portions.
Solution Approach 2:
The second pawl portion is made movable relative to the first pawl portion in the rotating direction, allowing the pawl structure to dynamically adapt to clearance conditions while maintaining stable meshing engagement and proper force transmission to the guide walls.
2Ease of operation
If clearances are formed between the pawl and guide walls to secure slidability, then the pawl can advance and retreat smoothly, but backlash occurs and looseness is generated in the locked condition
Solution Approach 1:
Dividing the pawl into two portions that can move relative to each other allows the system to maintain clearance for smooth sliding operation while eliminating backlash in the locked condition through the coordinated movement of the portions.
Solution Approach 2:
The first and second pawl portions act as intermediaries between the cam and the gear, mediating the transmission of force while accommodating clearance requirements for slidability and preventing backlash through their relative movement capability.
Data Source
AI summary
In a reclining device, a pawl is guided by guide walls formed in a guide while both of side portions thereof are applied thereto, so as to be movable only radially inwards and outwards. The pawl is divided into two divisional pawls configured to obliquely contact with each other, so as to be pressed and moved away from each other in opposite lateral directions and to be pressed against the guide walls positioned in respective lateral directions when the pawl is pressed and moved in the advancing direction by the pressing cam. A division line is set to form inclined surfaces that are configured to bring the two divisional pawls into face contact with each other obliquely with respect to the advancing moving direction of the pawl, and vertical surfaces that are configured to bring the two divisional pawls into face contact with each other in a direction perpendicular to the pawl advancing moving direction.