Steering Device Axial Release Mechanism for Impact Absorption
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Solution Overview
Problem
The existing steering devices have a limited amount of movement during secondary collisions, as the steering shaft, outer pipe, and bearing move forward only until they collide with the torque sensor, restricting the impact absorption.
Innovation Solution
A steering device configuration that includes a tubular steering shaft, a tubular outer pipe, and a bearing, with a release mechanism that allows the steering shaft and outer pipe to move further forward by releasing restraints when the bearing collides with the front body, utilizing slits and stepped surfaces to enhance movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the bearing is disposed in front of the torque sensor during secondary collision, then the steering shaft, outer pipe, and bearing move forward in an integrated manner, but the amount of movement (stroke) is limited because the bearing collides with the torque sensor
Solution Approach 1:
The front end portion of the outer pipe is divided into multiple segments that can separate from each other during collision. The outer pipe includes a first outer pipe portion and a second outer pipe portion that are separated by a partition wall, allowing independent movement of each segment during the collision process, thereby increasing the total movement distance.
Solution Approach 2:
The restraint mechanism between the bearing and the outer pipe is made dynamic through the separation mechanism. The bearing is restrained by the outer pipe under normal conditions, but this restraint is released when collision occurs, allowing the bearing and outer pipe segments to move independently forward, converting a static restraint system into a dynamic one that adapts to collision conditions.
2Device complexity
If the steering shaft, outer pipe, and bearing move forward in an integrated manner during secondary collision, then the structure is simple, but the amount of movement is insufficient for adequate impact absorption
Solution Approach 1:
The outer pipe is segmented into multiple movable portions (first outer pipe portion and second outer pipe portion) that can separate during collision. This segmentation allows the system to achieve greater total movement without requiring a completely complex multi-component structure, maintaining relative simplicity while increasing stroke.
Solution Approach 2:
The bearing is nested within the outer pipe structure, and the outer pipe segments are nested within each other. The first outer pipe portion contains the bearing, which in turn contains the steering shaft. This nested arrangement allows compact packaging while enabling sequential movement of nested components during collision, increasing overall movement distance without proportionally increasing external dimensions.
Data Source
AI summary
A steering device includes: a steering shaft; an outer pipe; a first bearing that causes the steering shaft to be rotatable with respect to the outer pipe; and a front body that is disposed in front of the bearing in an axial direction, and the steering shaft; in which a first space into which the steering shaft is capable of being inserted is formed on a radially inner side of the front body, and a second space into which the outer pipe is capable of being inserted is formed on a radially outer side of the front body, and the steering device further includes a release mechanism that releases a relative restraint between the first bearing, a first front end portion, and a second front end portion in the axial direction in a case where the first bearing collides with the front body during the secondary collision.