Vehicle Seat Actuator Beam Layout for Balanced Load Paths
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Solution Overview
Problem
Traditional vehicle seats are unbalanced, complex, heavy, and costly due to offset actuators and rigid motor assemblies, which limit design freedom and load path optimizations, especially in seats with integrated seat belts that need to absorb high impact forces.
Innovation Solution
A vehicle seat design featuring a lower frame and an upper frame pivotably connected via an actuating assembly with two actuators and a beam structure, allowing floating connections that optimize load paths and enable synchronized electric motors for balanced construction and efficient load distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a single actuator with offset positioning is used to adjust the seat structure, then the actuator can be positioned to achieve adjustment function, but the construction becomes unbalanced and requires torsional stiff frame which increases complexity, cost, and weight
Solution Approach 1:
The patent applies asymmetry by positioning two actuators symmetrically on opposite sides of the seat structure, which balances the load paths and eliminates the need for offset positioning. This symmetric arrangement distributes forces evenly across the frame, reducing torsional stress and allowing for a simpler, lighter frame construction while maintaining full adjustment functionality.
Solution Approach 2:
The patent uses the concept of counterbalancing by placing actuators on both sides of the seat structure. The actuators work in opposition to each other, with one extending while the other retracts, creating a balanced system that cancels out unbalanced forces and moments on the frame, thereby reducing the required frame stiffness and overall complexity.
2Device complexity
If the gearbox and motor assembly are rigidly fixed as part of the load path, then the actuator structure is simplified, but the load path and actuator cannot be individually tuned and design freedom is limited
Solution Approach 1:
The patent segments the actuator system into independent components: the motor assemblies are mounted separately on the seat structure, and the drive shafts connect to the actuators through flexible couplings. This segmentation allows the motor assemblies to be positioned and tuned independently from the load-bearing actuator mechanisms, providing design freedom to optimize both the drive system and the load path separately.
Solution Approach 2:
The patent introduces flexible couplings as intermediary elements between the motor assemblies and the actuator mechanisms. These couplings serve as mediators that transmit torque while allowing relative movement and misalignment, enabling independent tuning of the motor mounting positions and the actuator load paths without rigid constraints.
3Ease of operation
If traditional actuator positioning is used, then the seat can be adjusted, but the construction becomes heavy and costly due to the need for torsional stiff frame
Solution Approach 1:
By positioning actuators symmetrically on opposite sides of the seat structure, the patent creates a balanced system that distributes loads evenly. This eliminates the need for heavy torsional stiffening of the frame, allowing the use of lighter materials and simpler structural design while maintaining full seat adjustability and structural integrity under load.
4Device complexity
If motors are rigidly fixed in the load path, then the actuator assembly is compact, but design freedom and load path optimizations are limited, especially for integrated seat belts with high impact forces
Solution Approach 1:
The patent segments the actuator system into independently mounted motor assemblies and separate actuator mechanisms. The motor assemblies are mounted on the seat structure with flexible couplings to the drive shafts, allowing the load paths to be optimized independently. This segmentation enables the design to accommodate high impact forces from integrated seat belts by creating dedicated load-bearing paths that are separate from the motor mounting structures.
Solution Approach 2:
Flexible couplings serve as intermediary elements that decouple the motor assemblies from the load-bearing actuator mechanisms. This allows the motor mounts to be designed for compactness while the actuator load paths can be independently optimized for strength and impact force absorption, particularly important for integrated seat belt systems.
Data Source
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AI summary
A vehicle seat comprising a lower frame and an upper frame, where the upper frame is pivotably arranged in relation to the lower frame. The upper frame is movably connected to the lower frame via an actuating assembly, where the actuating assembly comprises a first actuator and a second actuator configured to cooperate with each other for displacing the upper frame in relation to the lower frame. The actuating assembly further comprises a beam structure connected to and extending between the first actuator and the second actuator, where the first actuator and the second actuator are floatingly connected to the lower frame via the beam structure.