Hybrid Inner Cam Assembly for Steering Rake Adjustment
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Solution Overview
Problem
High lift powdered metal inner cams in vehicle steering systems suffer from low surface density, leading to potential fracture and increased wear during locking and unlocking cycles, which affects durability and hardness.
Innovation Solution
A hybrid inner cam assembly formed of different materials, where a plastic housing contains metallic pegs with a ramped cam surface, providing improved density and wear resistance, and integrating features like rotational stops and travel bumpers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If a high lift profile is used in the powdered metal inner cam, then the steering column achieves sufficient vertical adjustment range, but the surface density becomes low leading to fracture risk and increased wear
Solution Approach 1:
The patent applies composite materials by combining a powdered metal inner cam with a different material (such as polymer or metal matrix composite) to create a hybrid cam structure. This composite approach allows the cam to maintain high lift profile while the composite material provides enhanced surface density and wear resistance, resolving the contradiction between adjustment range and durability
Solution Approach 2:
The patent implements local quality by applying different material properties to different regions of the inner cam. The surface layer is designed with higher density and hardness characteristics to resist wear and fracture, while the core maintains the high lift profile geometry. This localized material differentiation allows the cam to simultaneously achieve high lift and durability
2Length of moving object
If a high lift profile is used in the powdered metal inner cam, then the steering column achieves sufficient vertical adjustment range, but the surface hardness decreases leading to increased wear during locking and unlocking cycles
Solution Approach 1:
The patent uses composite materials where a harder material (such as a metal matrix or ceramic-containing composite) is combined with the powdered metal base material. This composite structure provides a harder surface layer that resists wear during locking and unlocking cycles, while maintaining the overall high lift profile for adequate adjustment range
Solution Approach 2:
The patent applies parameter changes by modifying the material composition and density parameters of the inner cam surface. Through controlled material selection and manufacturing processes, the surface density and hardness parameters are increased while maintaining the high lift geometric profile, thereby reducing wear without sacrificing adjustment capability
Data Source
AI summary
A steering column assembly includes a jacket pivotable about a rake axis. The steering column assembly also includes a rake adjustment assembly that includes a lever rotatable to lock and unlock the rake adjustment assembly. The rake adjustment assembly also includes a lever cam operatively coupled to, or integrally formed with, the lever. The rake adjustment assembly further includes an inner cam assembly in contact with the lever cam, wherein the inner cam assembly is formed of two different materials.