Front Subframe Rotational Member for Toe-In Steering
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Solution Overview
Problem
Current vehicle body structures face challenges in absorbing and transferring energy during small overlap offset collisions without relying on the front side frame, leading to increased weight and cost, and existing solutions like tie rod bending members are difficult to implement due to complexity and length, which interferes with normal steering operations.
Innovation Solution
A front vehicle body structure featuring a pair of front side frames, a front sub frame, a tie rod, a tie rod pressing member, and a rotational movement generating member that deforms to steer the front wheels in a toe-in direction during collisions, preventing them from hitting the side sill, while maintaining a simple and compact design that does not interfere with normal steering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the cabin is reinforced with a reinforcement member to improve collision safety performance, then collision safety is improved, but vehicle weight and cost increase significantly
Solution Approach 1:
The vehicle body structure is divided into functional zones: the front side frame handles large overlap collisions, while the separate rotational movement generating member and tie rod pressing member specifically address small overlap collisions. This segmentation allows targeted reinforcement without全面加强 the entire cabin structure.
Solution Approach 2:
Reinforcement is applied locally at critical positions (front sub frame, rotational movement generating member, tie rod pressing member) rather than uniformly throughout the cabin. The reinforcement member is specifically positioned to generate rotational movement during small overlap collisions, providing localized strength where needed without adding unnecessary weight elsewhere.
2Strength
If a tie rod bending member is disposed away from the steering range to prevent wheel collision, then collision safety is improved, but the member length increases and normal steering is interfered with
Solution Approach 1:
The tie rod pressing member is designed to be dynamically positioned: during normal steering operations, it remains retracted and does not interfere with the steering range, but during small overlap collisions, it rotates outward to press the tie rod and enable toe-in steering. This dynamic positioning eliminates the need for excessive member length while maintaining collision safety.
Solution Approach 2:
The rotational movement generating member is pre-positioned on the front sub frame in a retracted state during normal operation. Upon collision impact, it automatically rotates outward to the active position, preliminarily preparing the tie rod pressing action before the collision force is fully transmitted, ensuring immediate response without requiring excessive member length.
3Strength
If the tie rod is pushed backward with large stroke to bend the tie rod effectively, then collision safety is improved, but reproducibility of the movement is insufficient
Solution Approach 1:
The rotational movement generating member utilizes curved or inclined surfaces to convert the linear collision force into rotational movement. This curved geometry naturally guides the pressing member through a controlled arc, ensuring reproducible rotational movement and tie rod bending without requiring excessive linear stroke, thereby improving reliability.
Solution Approach 2:
The system changes the movement parameter from large linear stroke to controlled rotational displacement. By converting the pressing action into rotational movement around a pivot point, the system achieves effective tie rod bending with smaller, more reproducible displacements, improving the reliability and consistency of the collision response.
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 solution effectively improves collision safety performance by steering the front wheels in a toe-in direction during small overlap offset collisions without increasing vehicle weight or interfering with normal steering, enhancing energy absorption and reducing the risk of wheel collision with the side sill.
Implementation Method 1
configured to cause the tie rod pressing member to generate a rotational movement by bending and deforming an area in a direction in which a rear side of the area opens outward in a vehicle width direction with respect to a front side of the area, using a load received from a forward position of the vehicle at a time of a collision
Data Source
AI summary
There is provided a front vehicle body structure including: a front sub frame mounted below front side frames; a tie rod disposed forwardly of an axle; a tie rod pressing member having a pressing portion which is mounted on the front sub frame forward of the tie rod and presses the tie rod when a collision occurs; and a rotational movement generating member for causing the tie rod pressing member to generate a rotational movement by deforming an area on which the tie rod pressing member is mounted in the front sub frame, by the load received when a collision occurs. The pressing portion is displaced by the rotational movement from a first position which is out of a steering range of the front wheels to a second position at which the pressing portion swings outward in the vehicle width direction and which allows pressing of the tie rod.