Vehicle Seat Reclining Device Cam Mechanism
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Solution Overview
Problem
The existing reclining device for vehicle seats experiences issues with smooth pawl movement and tooth jumping, leading to ineffective locking due to increased frictional resistance and rattling between the pawl and guide.
Innovation Solution
A reclining device with a cam mechanism that includes a first cam and a second cam to guide the pawl from an unlocked to a locked position, reducing frictional resistance and preventing tooth jumping by initially pressing the pawl with the first cam and then the second cam, ensuring smooth engagement of external and internal teeth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the second cam presses the pawl against the guide to eliminate rattling, then locking strength is improved, but the pawl cannot move smoothly when transitioning from unlocked to locked position
Solution Approach 1:
The pressing action is segmented into two distinct phases: first the first cam presses the pawl to enable smooth movement without guide contact, then the second cam presses the pawl against the guide for secure locking. This segmentation allows each cam to optimize for its specific function, resolving the contradiction between smooth movement and locking strength.
Solution Approach 2:
The first cam performs a preliminary pressing action before the second cam engages. This preliminary action prepares the pawl for smooth transition by pressing it without guide contact, and only after this preliminary phase does the second cam engage to press the pawl against the guide for final locking, ensuring both smooth movement and strong locking.
2Stability of the object's composition
If the pawl is pressed against the guide during locking, then rattling is eliminated, but frictional resistance increases causing tooth jumping
Solution Approach 1:
The locking process is segmented into two phases: first the pawl moves without guide contact to avoid excessive friction and tooth jumping, then after engagement begins, the second cam presses the pawl against the guide to eliminate rattling and improve stability. This segmentation ensures reliability by avoiding friction-induced tooth jumping while achieving stability in the final locked state.
Solution Approach 2:
The pawl is first moved into engagement position without being pressed against the guide, allowing smooth transition without tooth jumping. Only after engagement is initiated does the second cam apply pressure against the guide to eliminate rattling, thus preliminarily establishing engagement before applying stabilizing pressure.
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 smooth pawl movement and prevents tooth jumping, enhancing the locking operation and maintaining locking strength by minimizing rattling and friction, thus improving the overall performance of the reclining mechanism.
Implementation Method 1
reducing frictional resistance and preventing tooth jumping by initially pressing the pawl with the first cam and then the second cam
Implementation Method 2
The release arm 142 is applied with an urging force by a spring 150 in such a direction that the first cam 144 presses the pawl 134 via the second cam 141
Implementation Method 3
an inner end portion of a spiral spring 156, of which an outer end portion is locked to the pin 155 provided to stand on the latchet plate 132, locked to the groove, so that the latchet plate 132 (upper arm) is urged in a forward tilting direction
Data Source
AI summary
[Problem] The present invention addresses the problem of providing a reclining device in which a pawl moves smoothly, does not slip and locks well.[Solution] A cam part that moves a pawl (33) in the direction of a locked position is configured from a rotating cam (first cam) (31) that pushes the pawl (33) in the direction of the locked position and a cam (second cam) (34) that is pressed by the rotating cam (31) and pushes the pawl (33) in the direction of the locked position while pressing same against a guide (25c). The cam part is configured so that when the pawl (33) located at the unlocked position moves to the locked position, the cam part initially presses the pawl (33) with the rotating cam (31), and when the pawl (33) is at the locked position, presses the pawl (33) with the cam (34).