Cushion Spring Structure for Stable Seat Side Roll Rigidity
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Solution Overview
Problem
Existing cushion springs struggle to stably increase roll rigidity of the side portion of a seat cushion, leading to potential elasticity weakening and variations in hardness, which affects the comfort and stability of the seating experience.
Innovation Solution
A cushion spring design featuring formed wires with crank-shaped portions and a resin member that restricts deflection, providing a pad supporting surface to enhance roll rigidity and adjust hardness distribution for improved comfort and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the center wire and side wire are made symmetrical, then the manufacturing is simplified, but the roll rigidity of the side portion cannot be stably increased
Solution Approach 1:
The patent applies asymmetry by making the side wire have a different configuration from the center wire. Specifically, the side wire includes a resin member with a deflection restricting portion that connects three or more crank-shaped portions, while the center wire does not have this resin member. This asymmetric design allows the side portion to have increased roll rigidity while maintaining manufacturing feasibility through standardized wire forming processes.
Solution Approach 2:
The patent applies local quality by providing the resin member with deflection restricting portions only at the side wire locations where roll rigidity needs to be increased. The resin member is positioned to restrict divergence between crank-shaped portions specifically in the side portions, while the center portion maintains its original flexibility. This localized modification achieves stable roll rigidity increase without requiring complete redesign of the entire wire structure.
2Strength
If the hardness of the cushion pad is partially changed to increase roll rigidity, then the side portion rigidity improves, but elasticity weakening and hardness variation occur
Solution Approach 1:
The patent applies composite materials by combining the wire structure with a resin member to create a hybrid construction. The resin member has different mechanical properties than the wire, providing deflection restriction while maintaining the elasticity of the wire. This composite approach allows the side portion to have increased roll rigidity through the resin's structural support while the wire maintains its elastic properties, avoiding the elasticity weakening that would occur with homogeneous hardening.
3Strength
If the side wire deflection is restricted, then the roll rigidity increases, but the comfort may be reduced
Solution Approach 1:
The patent applies local quality by providing deflection restriction only in the side portions where roll rigidity is needed, while the center portion maintains full flexibility for comfort. The resin member is positioned to restrict divergence between crank-shaped portions at the sides, but does not interfere with the natural deflection of the center wire. This localized approach ensures that roll rigidity is increased where needed without compromising overall seating comfort.
Data Source
AI summary
There is provided a cushion spring including: a formed wire bridged to a seat cushion frame in a seat front-rear direction; and a resin member joined to the formed wire. A center wire and a side wire of the formed wire each include a plurality of crank-shaped portions that are bent to fold in a crank shape to one side and the other side in a seat width direction alternately. The resin member includes a deflection restricting portion that connects the plurality of crank-shaped portions to restrict a divergence in the seat front-rear direction between three or more crank-shaped portions, the three or more crank-shaped portions being formed in the side wire and arranged side by side consecutively in the seat front-rear direction.