Vehicle Seat Torsion Spring Link Mechanism
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Solution Overview
Problem
Conventional vehicle seat designs face challenges in reducing the operating force required to tilt a seatback forward due to limitations in effective link length caused by the use of linearly deforming springs, which restrict the placement of spring hooks and result in insufficient link length.
Innovation Solution
The implementation of a torsion spring wound around the pivotally-connected portion of the operation link allows for a longer effective link length, reducing the operating force needed to pivot the seatback forward, and the use of an elongated operation link and release link mechanism that extends in the same direction as the operating member, facilitating easier operation from behind the seat.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If a tension spring or compression spring is used to bias the operation link, then the spring can be installed linearly, but the spring hook position must be set outward from the pivotally-connected portion, which reduces the effective link length
Solution Approach 1:
The patent changes the spring type from linearly deforming (tension/compression spring) to torsionally deforming (torsion spring). This parameter change allows the spring to be installed at the pivotally-connected portion rather than outward from it, thereby maximizing the effective link length while maintaining the biasing function.
Solution Approach 2:
The patent transitions from linear deformation (one-dimensional) to torsional deformation (rotational dimension). The torsion spring winds around the pivotally-connected portion and applies biasing force through rotational deformation, enabling the spring hook to be positioned at the pivot point itself rather than outward from it.
2Force
If the spring hook position is set outward from the pivotally-connected portion, then the spring can be installed, but the effective link length is reduced making it difficult to reduce operating force
Solution Approach 1:
By changing the spring deformation mode from linear to torsional, the patent enables the spring hook to be positioned at the pivotally-connected portion. This maximizes the effective link length, which directly reduces the operating force required to pivot the operation link and tilt the seatback forward.
3Force
If the operation link is made elongated to increase effective link length, then operating force is reduced, but the spring installation space becomes insufficient when using linear springs
Solution Approach 1:
The patent uses torsional deformation instead of linear deformation, changing the space requirement from linear extension to rotational winding around the pivotally-connected portion. This allows the operation link to be elongated for reduced operating force without requiring additional linear installation space for the spring.
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 significantly reduces the operating force required to tilt the seatback forward, enabling easier operation while maintaining a sufficient effective link length and allowing occupants to adjust the reclining angle with minimal effort.
Implementation Method 1
a torsion spring that is wound around a pivotally-connected portion at which the link mechanism is pivotally connected to the second end of the operation link, and that biases the operation link such that the operation link is pivoted toward an initial position in which the operation link is located before being operated
Data Source
AI summary
A vehicle seat is provided with an operation member operated to tilt a seatback forward and disposed at such a position as to be operated from behind a seat body. The vehicle seat includes: an operation link connected at one end to the operation member and operated to be pivoted; a link mechanism that is pivotally connected to a lower end of the operation link, receives force, generated by an operation of the operation member, from the operation link to be moved, and outputs the force for cancelling fixation of a reclining angle of the seatback; and a torsion spring that is wound around a pivotally-connected portion at which the link mechanism is pivotally connected to the operation link, and biases the operation link such that the operation link is pivoted toward an initial position in which the operation link is located before being operated.