Grooved Intermediate Shaft for Steering Energy Absorption
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Solution Overview
Problem
Existing intermediate shaft designs for vehicle steering systems require costly hydroforming processes to achieve the necessary buckling performance for crash safety, and they often occupy more space due to outwardly formed convolute geometry.
Innovation Solution
A grooved intermediate shaft design that allows deformation when a predetermined force is exceeded, featuring radially inwardly extending grooves that do not protrude beyond the radially outer surface of the main body, thereby reducing packaging space and manufacturing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If outwardly formed convolute geometry is used to achieve buckling performance, then crash safety is improved, but manufacturing cost increases due to requiring specialized hydroforming process
Solution Approach 1:
Instead of forming grooves that protrude outward from the intermediate shaft surface, the patent inverts the approach by forming grooves that recess inward into the shaft body. This inversion eliminates the need for complex hydroforming processes while maintaining the energy absorption and buckling performance required for crash safety.
Solution Approach 2:
The patent changes the geometric parameters of the grooves, specifically their depth and orientation, to achieve the desired buckling behavior. By controlling the groove depth to be less than the outer radius of the intermediate shaft and positioning them at specific angular intervals, the shaft achieves predictable deformation characteristics during impact without requiring costly specialized manufacturing.
2Reliability
If outwardly formed convolute geometry is used to achieve buckling performance, then crash safety is improved, but packaging space increases due to radial protrusion
Solution Approach 1:
The patent inverts the conventional approach by recessing grooves into the intermediate shaft rather than protruding outward. This ensures that the entire grooved portion remains within the radially outer surface of the main body, eliminating radial protrusion and reducing the overall volume and packaging space required while maintaining crash safety through controlled deformation.
3Volume of moving object
If grooves are formed radially inwardly without exceeding the radially outer surface, then packaging space is reduced, but manufacturing complexity may increase
Solution Approach 1:
The patent specifies precise geometric parameters for the grooves, including depth limits (not exceeding the outer radius) and angular spacing (e.g., 90 degrees apart). These controlled parameters simplify the manufacturing process by providing clear design criteria that can be achieved through conventional machining methods, reducing manufacturing complexity despite the inward groove configuration.
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 grooved intermediate shaft effectively absorbs energy during impact events, reducing the force transmitted to the occupant and improving vehicle safety, while also simplifying the manufacturing process and reducing costs.
Implementation Method 1
a grooved portion located along the main body and defining at least one groove to allow deformation of the main body when a predetermined force on the main body is exceeded
Data Source
AI summary
An intermediate shaft for a steering system includes a main body having a radially outer surface. The intermediate shaft also includes a grooved portion located along the main body and defining at least one groove to allow deformation of the main body when a predetermined force on the main body is exceeded, wherein the entirety of the grooved portion does not radially exceed the radially outer surface of the main body.