Reclining Device with Dual Wedge-Shaped Members for Load Distribution
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Solution Overview
Problem
Conventional reclining devices require a large operating force to initiate tilting due to high static friction, leading to potential rearward falling of the seat back when tilted, as all force is transmitted through the first wedge-shaped member, resulting in inadequate load distribution and resistance.
Innovation Solution
A reclining device design where both the first and second wedge-shaped members receive the load from the seat back, with the external gear having fewer teeth than the internal gear, allowing simultaneous engagement and application of force to both members, thereby distributing the load and reducing the likelihood of the seat back falling rearward.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If all force is transmitted through the first wedge-shaped member, then the structure is simple, but the operating force becomes too large and the seat back falls rearward
Solution Approach 1:
The force transmission path is segmented into two separate paths: one through the first wedge-shaped member and another through the second wedge-shaped member. This segmentation distributes the load from the seat back to both members, reducing the force required to initiate tilting and preventing uncontrolled rearward motion.
2Ease of operation
If the second wedge-shaped member is added to distribute load, then the ease of operation improves, but the device complexity increases
Solution Approach 1:
The force transmission structure is divided into two parallel segments, each with its own wedge-shaped member. This segmentation allows load distribution while maintaining a relatively simple overall structure that integrates smoothly with the existing gear mechanism.
Solution Approach 2:
The first and second wedge-shaped members are combined to work together in a coordinated manner, both receiving load from the seat back and both contributing to the tilting operation. This merging of force paths creates a more robust system without significantly increasing complexity.
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 design ensures that the seat back is less likely to fall rearward suddenly during tilting, as the second wedge-shaped member acts as a brake, requiring less operating force and maintaining stability by distributing the load effectively.
Implementation Method 1
a first wedge-shaped member 5 and a second wedge-shaped member 7 are urged by a spring 9 in a direction (a direction of an arrow A and a direction of an arrow B) in which a wedge is driven into the eccentric annular space
Implementation Method 2
When the first wedge-shaped member 5 and the second wedge-shaped member 7 are pressed against the inner surface of the circular hole 1 and the outer surface of the cylinder part 3, the internal gear 15 and the external gear 17 are urged in a direction in which the amount of eccentricity between the rotation axes of both is increased
Implementation Method 3
At the start of movement of one of the first wedge-shaped member 5 and the second wedge-shaped member 7, the other of the second wedge-shaped member 7 and the first wedge-shaped member 5 remains stationary by friction between the inner surface of the circular hole 1 and the outer surface of the cylindrical part 3
Implementation Method 4
as the one of the wedge-shaped members moves in the pull-out direction, the other wedge-shaped member moves all at once by an elastic repulsive force of the spring 9 in a direction in which the wedge is driven into the eccentric annular space
Data Source
AI summary
Provided is a reclining device that prevents a seat back from falling rearward all at once when reclined rearward. The reclining device has an external gear (63), which has a cylinder (63c) at the center, an internal gear (61), which has internal teeth that engage with the external gear (63) and a circular hole (61e) in which the cylinder (63c) is inserted, and a first wedge-shaped member (71) and a second wedge-shaped member (73), which are provided between the inner surface of the circular hole (61e) and the outer surface of the cylinder (63c). The reclining device is configured such that a load from the seat back is simultaneously applied to the first wedge-shaped member (71) and second wedge-shaped member (73).