Polygonal Torsion Bar Geometry for Easier Spring-Rate Manufacturing
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Solution Overview
Problem
The existing manufacturing processes for torsion bars in power steering assemblies are expensive and time-consuming due to the need for precise fabrication of serrated ends and specified spring rates, which complicates the production of torsion bars with desired torsional spring properties.
Innovation Solution
A torsion bar with a uniform polygon or polygon-like cross-section and chamfered ends is proposed, allowing for a cost-effective and efficient manufacturing method involving stock material formation through processes like extrusion or cold forming, followed by cutting and chamfering to facilitate a force fit with steering components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional manufacturing processes are used to fabricate torsion bars with serrated ends and specified spring rates, then the torsion bars achieve desired torsional spring properties, but the manufacturing process becomes expensive and time-consuming
Solution Approach 1:
The patent changes the geometric parameters of the torsion bar by using a polygonal cross-section instead of a traditional circular cross-section. This parameter change allows the torsion bar to achieve the desired torsional spring properties through its shape alone, eliminating the need for complex serrated end fabrication and enabling more economical manufacturing processes.
Solution Approach 2:
Instead of starting with a circular cross-section and adding complexity (serrations, machining), the patent inverts the approach by using a polygonal cross-section that inherently provides the required torsional characteristics. This inversion simplifies the manufacturing process by eliminating secondary operations.
2Manufacturing precision
If multiple manufacturing stages are used to produce torsion bars with serrated ends, then the desired spring rate is achieved, but the production process becomes complex and time-consuming
Solution Approach 1:
The patent employs parameter changes by substituting the traditional circular cross-section with a polygonal cross-section. This fundamental parameter change allows the torsion bar to achieve precise spring rates through its geometric configuration alone, eliminating the need for multiple manufacturing stages and reducing process complexity.
3Ease of manufacture
If traditional circular cross-section torsion bars are used, then the manufacturing process is well-established, but the production cost and time increase due to additional fabrication requirements
Solution Approach 1:
The patent changes the cross-sectional parameter from circular to polygonal, which fundamentally alters the manufacturing approach. This parameter change enables the torsion bar to be formed in fewer steps using processes like extrusion or drawing, significantly reducing manufacturing cycle time while maintaining ease of production through established metal forming techniques.
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 approach simplifies and reduces the cost of producing torsion bars with desired torsional spring properties, enabling faster and more economical manufacturing while maintaining effective torsional load carrying capacity and resistance to relative rotation.
Implementation Method 1
a torsion bar configured as a torsion spring with a torsional stiffness in order to facilitate the measuring of an input torque
Data Source
AI summary
A torsion bar is provided that is easy, quick, and cost effective to manufacture. The torsion bar may extend along an axis and have a first end and a second end that is spaced from the first end. The torsion bar may have an active section positioned between the first and second ends. The active section may also have a length defined along the axis. A cross-section transverse to the axis may define a contour of the torsion bar where the contour may be uniform along the length of the active section. The contour may define at least one of a polygon and a polygon-like shape.