Steering Rack Boot With Variable Axial Rigidity
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Solution Overview
Problem
Conventional steering boots suffer from undulating deformation due to temperature changes, leading to interference with ball joints and increased manufacturing costs, with existing solutions requiring heat treatment and complex mold designs that increase man-hour requirements and material rigidity issues.
Innovation Solution
A steering boot design featuring a major-diameter fastener, first and second bellows, and a minor-diameter-side bellows with optimized axial rigidity, where the first and third axial rigidities are lower than the second, allowing for reduced deformation without heat treatment and simplified mold machining, using a tapered configuration and varying membrane axial rigidity to inhibit undulating deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the steering boot is made with uniform axial rigidity throughout, then the manufacturing process is simple, but the boot undergoes undulating deformation when internal pressure rises
Solution Approach 1:
The bellows is divided into multiple sections with different axial rigidities. The first bellows section has lower axial rigidity to allow expansion, while the second bellows section has higher axial rigidity to maintain shape stability and prevent undulating deformation. This local differentiation of mechanical properties solves the contradiction between manufacturing simplicity and shape stability.
2Stability of the object's composition
If heat treatment is applied to the steering boot to inhibit undulating deformation, then the boot shape stability is improved, but the manufacturing time and cost increase
Solution Approach 1:
Instead of applying heat treatment after molding to correct deformation, the invention incorporates the rigidity differentiation directly into the mold design during the initial molding process. The mold includes positioning protrusions and recesses that pre-establish the correct bellows configuration, eliminating the need for subsequent heat treatment and reducing manufacturing time.
3Stability of the object's composition
If the bellows is designed with complex rigidity variations to prevent deformation, then the shape stability is improved, but the mold complexity and machining time increase
Solution Approach 1:
The bellows is segmented into distinct sections (first bellows and second bellows) with different rigidity characteristics. Each section can be independently designed and molded, allowing for controlled rigidity variation without requiring an overly complex monolithic mold. The segmentation simplifies the overall mold design while achieving the desired shape stability.
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 boot effectively inhibits undulating deformation, reduces manufacturing costs, and maintains structural integrity without heat treatment, ensuring reliable operation and cost-effectiveness.
Implementation Method 1
the first bellows exhibiting an averaged first axial rigidity; the second bellows exhibiting an averaged second axial rigidity; the minor-diameter-side bellows exhibiting an averaged third axial rigidity; and the averaged first axial rigidity and the averaged third axial rigidity being lower than the averaged second axial rigidity
Data Source
AI summary
A boot includes a major-diameter fastener, a first bellows, a second bellows, a minor-diameter-side bellows, and a minor-diameter fastener. The major-diameter fastener is to be fastened to a mating major-diameter member. The first bellows is disposed continuously from the major-diameter fastener. The second bellows is disposed continuously from the first bellows. The minor-diameter-side bellows is disposed continuously from the second bellows. The minor-diameter fastener is disposed continuously from the minor-diameter-side bellows, and is to be fastened to a mating minor-diameter member. The first bellows exhibits an averaged first axial rigidity. The second bellows exhibits an averaged second axial rigidity. The minor-diameter-side bellows exhibits an averaged third axial rigidity. The averaged first axial rigidity and the averaged third axial rigidity are lower than the averaged second axial rigidity.