Vehicle Seat Leaf Spring Four-Bar Linkage Kinematics
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Solution Overview
Problem
Existing vehicle seat designs are not cost-effective and lack efficient mechanisms for transitioning between use and non-use positions, particularly in controlling the kinematic system for backrest movement.
Innovation Solution
A vehicle seat design utilizing a multi-bar mechanism, specifically a four-bar mechanism temporarily formed by a leaf spring, which provides a single degree of freedom for transitioning into a non-use position and can also control inclination and height adjustments, using a leaf spring as a gear member that functions as both a tension and pressure spring to counteract gravitational forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a pneumatic spring is used as a resilient unit, then the backrest can be supported during transition, but the device complexity and cost increase
Solution Approach 1:
The patent changes the type of spring from pneumatic to mechanical (leaf spring), altering the physical parameters and mechanism of force application. This substitution maintains the support function while simplifying the overall kinematic system and reducing cost.
Solution Approach 2:
The patent extracts the essential function of the resilient unit (providing support force) and implements it through a simpler mechanical leaf spring mechanism rather than a complex pneumatic system, removing unnecessary complexity while retaining the core functionality.
2Ease of operation
If a multi-bar mechanism is used to control the kinematic system, then the transition is controlled with single degree of freedom, but the device complexity increases
Solution Approach 1:
The patent employs a dynamic multi-bar mechanism that temporarily forms a four-bar mechanism during the transition phase to provide controlled single-degree-of-freedom movement, then neutralizes itself when the transition is complete, adapting its structure to the operational phase.
Solution Approach 2:
The multi-bar mechanism operates periodically: it is active and controlling during the transition phase, then neutralized during the stable position phase. This periodic activation reduces overall complexity by only engaging the control mechanism when needed.
3Ease of manufacture
If a leaf spring is used instead of a pneumatic spring, then the cost is reduced, but the force application capability may be limited
Solution Approach 1:
The patent changes the spring type from pneumatic to mechanical leaf spring, which provides sufficient force through elastic deformation. The leaf spring's geometry and material properties are optimized to deliver the required force magnitude and direction for backrest support.
Solution Approach 2:
The patent uses a leaf spring that replicates the essential force-application function of a pneumatic spring through a simpler, more cost-effective mechanical design, achieving the same functional outcome with reduced manufacturing complexity and cost.
4Device complexity
If the multi-bar mechanism is neutralized in the end phase, then the structural complexity is reduced, but the control precision may be lost
Solution Approach 1:
The multi-bar mechanism is periodically activated during the transition phase to ensure precise control, then neutralized in the final position. The precision requirement is met during the critical transition phase when the mechanism is active, while the neutralized phase accepts reduced precision as the seat is already in its target position.
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 design allows for a cost-effective transition between use and non-use positions with improved force introduction and reduced structural complexity, enabling stable and efficient movement control while minimizing the need for additional springs or gear connections, thus enhancing user interaction and safety.
Implementation Method 1
The leaf spring functions in the relaxed extended position thereof as a tension coupling, that is to say, it is subjected to tensile loading
Implementation Method 2
When the extended position, for example, owing to geometry, has to be left, the leaf spring bends and the temporary four-bar mechanism is neutralized. In the bent positions thereof, the leaf spring builds up tension, as a result of which it can act as a pressure spring, for example, in order to counteract the gravitational force of the backrest
Data Source
AI summary
A vehicle seat, in particular to a motor vehicle seat, having a base structure (3) that is to be connected to the vehicle structure (S) and a backrest (10) that can be moved relative to the base structure (3) by kinematics, such as to transfer the vehicle seat (1) from at least one usage position allowing a person to sit down to a non-usage position or to another usage position. A multi-bar linkage, in particular a four-bar linkage (V), exists at least temporarily, which linkage controls the kinematics. A leaf spring (30) is provided in the vehicle seat. The leaf spring forms a gear element of the multi-bar linkage in the relaxed extended state thereof.