Seat Recliner Cam-Pawl Structure for Lower Hook Bending Load
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Solution Overview
Problem
The existing reclining device for vehicle seats experiences a large bending moment on cantilever-shaped hook portions due to force transmission, necessitating increased thickness or high rigidity materials, which raises costs.
Innovation Solution
Incorporating a cam that disperses the rotational force between the pawl, guide, and rotating cam, reducing the load on the hook portion, allowing for a thinner design without high rigidity materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the hook portion is made thicker or high rigidity materials are used to withstand the bending moment, then the strength and rigidity are improved, but the manufacturing cost increases
Solution Approach 1:
The patent introduces a cam as an intermediary component between the rotating cam and the pawl. This cam mediates the force transmission by providing a contact surface that distributes the load, thereby reducing the bending moment on the hook portion without requiring thicker materials or higher rigidity materials
Solution Approach 2:
The patent segments the force transmission path by introducing the cam as a separate component. Instead of direct force transmission from the rotating cam to the pawl through the hook portion, the force is now transmitted through the cam, which divides and distributes the load, reducing the stress concentration on the hook portion
2Stability of the object's composition
If the thickness of the hook portion is increased to reduce bending moment, then the rigidity is improved, but the device complexity and cost increase
Solution Approach 1:
The cam serves as a mediator that maintains the rigidity requirement by properly distributing forces, eliminating the need to increase hook portion thickness. This keeps the structural design simple while meeting the rigidity requirement through intelligent force distribution rather than brute-force material increases
3Strength
If high rigidity materials are used to withstand the bending moment, then the strength is improved, but the manufacturing cost increases
Solution Approach 1:
The cam intermediary allows the use of standard, cost-effective materials for the hook portion by distributing the bending moment. The force distribution function is transferred to the cam, which can be designed with appropriate geometry to handle the loads, while the hook portion uses simpler, cheaper materials
Solution Approach 2:
The patent changes the geometric parameters of the cam to optimize force distribution. By adjusting the cam's profile and contact surfaces, the bending moment on the hook portion is reduced, allowing the use of materials with lower cost while maintaining sufficient strength
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
This configuration reduces the force transmitted to the hook portion, eliminating the need for increased thickness or high rigidity materials, thereby achieving a cost-effective reclining device solution.
Implementation Method 1
Incl a cam 34, which is pressed and contacted against the pawl 33 and the guide 25c when being pressed by the hook portion 31b due to the rotation of the rotating cam 31 in the one direction
Data Source
AI summary
A reclining device includes a first member, a second member which is stacked at an open side of the first member, a pawl which is movably provided with the second member, a rotating cam which is provided to be rotatable about an axis of the relative rotation and includes a hook portion having a hook shape a guide which is formed with the second member and guides the pawl between a locked position and the unlocked position and a cam which is provided among the rotating cam, the pawl and the guide.