Steering Device Second Housing Breaks on Impact
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing steering devices with worm gear mechanisms are susceptible to damage during collisions, which compromises their impact absorption function due to interference with other vehicle components like the brake pedal, leading to damage of the worm gear and worm wheel, resulting in ineffective impact absorption.
Innovation Solution
A steering device design featuring a second housing with a vulnerable part, such as a thin or small diameter section, that breaks upon impact, allowing the worm gear to remain mounted and functional, while absorbing forces through a telescopic mechanism between the inner and outer tubes, maintaining the impact absorption function.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the second housing is made strong to protect the worm gear, then the reliability of the housing is improved, but the harmful effect of interference with other vehicle components (like brake pedal) worsens
Solution Approach 1:
The second housing is divided into two functional zones: a vulnerable part with reduced thickness that allows controlled breakage during interference, and a protected part with normal thickness that maintains structural integrity for housing the worm gear. This segmentation allows the housing to serve dual purposes of protection and sacrificial interference absorption.
Solution Approach 2:
The vulnerable part of the second housing is designed as a sacrificial element that can break during interference events (like brake pedal collision). This disposable portion protects the more critical worm gear by absorbing impact through controlled failure, while the worm gear itself remains intact and reusable.
2Ease of manufacture
If the second housing is made with uniform thickness, then the manufacturing simplicity is improved, but the ability to provide targeted protection while allowing controlled breakage worsens
Solution Approach 1:
The second housing exhibits local quality variation through different wall thicknesses in different regions. The vulnerable part has reduced thickness to enable controlled breakage, while the protected part maintains normal thickness for structural support. This local differentiation allows the housing to provide targeted protection where needed while allowing controlled failure in non-critical areas.
3Reliability
If the worm gear is made robust to prevent damage, then the reliability of the impact absorption function is improved, but the interference with other vehicle components worsens
Solution Approach 1:
The vulnerable part of the second housing acts as an intermediary sacrificial element between the external interference (brake pedal) and the critical worm gear. This mediator absorbs the harmful impact through controlled breakage, protecting the worm gear from damage while still allowing the impact absorption function to operate when needed.
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 ensures effective impact absorption by maintaining the worm gear's interlocking state with the screw member, enhancing safety during emergencies without requiring significant modifications to the conventional steering device configuration.
Implementation Method 1
a worm gear (8) and a motor (M) being housed in a second housing (h) mounted to the first housing (H). The worm gear (8) rotates the screw member (7), and the motor (M) drives the worm gear (8).
Implementation Method 2
a screw member (7) being provided in the first housing (H), acting on the input unit (6), and making the input unit (6) reciprocable along the axial direction (X1)
Implementation Method 3
an inner tube (4) covering the shaft (3) in a rotatable manner; an outer tube (5) fitting around the inner tube (4)... the inner tube (4) and the outer tube (5) integrally extend/contract... the inner tube (4) and the outer tube (5) receive external force from the driver
Data Source
AI summary
A steering device of a vehicle includes: a shaft mounted with a steering wheel; an inner tube rotatably covering the shaft; an outer tube fitting around the inner tube; a first housing reciprocably housing the outer tube along an axis direction of the shaft; an input unit provided on the outer tube; a screw member being provided in the first housing, and making the input unit reciprocable along the axis direction; and a worm gear rotating the screw member, and a motor driving the worm gear, being housed in a second housing mounted to the first housing. A vulnerable part is provided in the second housing in such a way that, when impact applies to the vehicle and another object collides with the second housing, the second housing breaks while maintaining a mounting state of the worm gear.