Propeller Shaft Collapse Assembly for Crash Force Absorption
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Solution Overview
Problem
Conventional propeller shaft assemblies are prone to buckling and causing injury or damage during vehicle crashes, as they transmit forces that can penetrate the passenger compartment and harm nearby components.
Innovation Solution
A shaft assembly with a crash collapse assembly featuring a joint system where a first shaft is connected to a second shaft via increased diameter portions and a wall portion that fractures under crash forces, allowing axial translation into a hollow portion of the second shaft, thereby absorbing and dissipating the force.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional propeller shaft assemblies are used to transmit rotational energy, then power transmission efficiency is maintained, but the shafts buckle and penetrate the passenger compartment during crashes causing injury and damage
Solution Approach 1:
The propeller shaft is divided into multiple sections including a first shaft, a second shaft, and a telescopic section with a wall portion. This segmentation allows the telescopic section to absorb crash forces through controlled fracture and axial translation, preventing force transmission to the passenger compartment while maintaining power transmission capability during normal operation
Solution Approach 2:
The wall portion is designed to fracture under crash conditions, converting the harmful impact force into beneficial energy absorption. The controlled fracture and subsequent axial translation of the telescopic section dissipate crash energy, protecting passengers and nearby components while the joint assembly maintains drivetrain connectivity
2Stability of the object's composition
If the propeller shaft is designed to be rigid for stable power transmission, then transmission reliability is improved, but crash forces are transmitted to nearby components causing damage
Solution Approach 1:
The propeller shaft incorporates a dynamic telescopic section that can change its structural state based on operating conditions. During normal operation, the wall portion maintains rigidity for stable power transmission. During crash conditions, the wall portion fractures and the telescopic section allows axial movement, dynamically adapting to absorb impact forces and protect nearby components
3Reliability
If a crash collapse assembly is added to absorb crash forces, then passenger safety is improved, but device complexity increases
Solution Approach 1:
The crash collapse assembly utilizes a nested telescopic structure where the first shaft and second shaft are concentrically arranged with the telescopic section positioned between them. The wall portion of the telescopic section is nested within the hollow portion of the second shaft, allowing compact integration of the crash absorption mechanism within the existing propeller shaft geometry without significantly increasing overall device complexity
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 shaft assembly effectively absorbs crash forces, reducing the risk of passenger injury and component damage by fracturing the wall portion to allow axial translation, ensuring safe operation during normal conditions and enhanced safety during crashes.
Implementation Method 1
an amount of force is applied to the wall portion until it fractures and at least a portion of the first shaft and/or the joint assembly translates axially into a hollow portion of the second shaft
Data Source
AI summary
A shaft assembly. The shaft assembly includes a joint assembly having a first joint member, a second joint member and one or more third joint members drivingly connecting said first and second joint members. At least a portion of a first shaft is drivingly connected to the second joint member. Circumferentially extending from at least a portion of an outer surface of a second end portion of the first shaft is a first and second increased diameter portion having a wall portion that connects the first increased diameter portion to the second increased diameter portion. Drivingly connected to the second increased diameter portion of the first shaft is a second shaft. During a crash condition, an amount of force is applied to the wall portion until it fractures and at least a portion of the first shaft and/or the joint assembly translates into a hollow portion of the second shaft.