Steering Wheel Cam Device Anti-Unlocking Design
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Solution Overview
Problem
The existing cam devices in steering wheel position adjustment systems face issues with the drive-side cam easily rotating relative to the driven-side cam in the locked state, leading to potential unintended unlocking when an impact is applied, and the wear of gradient sections reduces their effectiveness over time, increasing the operating force required for the adjustment lever.
Innovation Solution
The cam device is designed with a drive-side cam that is rotatably supported and a driven-side cam that is unrotatably supported, featuring tip-end butt sections on the outer-diameter side portions and tip-end concave sections on the inner-diameter side portions, along with inclined sliding sections and concave sections, to prevent relative rotation and maintain smooth operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If gradient sections are provided on the tip-end surface of convex sections to prevent relative rotation, then the locked state stability is improved, but the gradient sections wear over time reducing their effectiveness and increasing operating force
Solution Approach 1:
The tip-end surface of the convex section is segmented into two distinct functional zones: an inclined sliding section for smooth engagement and a flat butt section for preventing relative rotation. This segmentation eliminates the wear problem of continuous gradient sections while maintaining the anti-rotation function.
Solution Approach 2:
Different regions of the tip-end surface are given different properties: the inclined sliding section provides smooth engagement with reduced friction, while the flat butt section provides rotational prevention through direct contact. Each local region is optimized for its specific function.
2Ease of operation
If the drive-side cam is rotatably supported to enable locking mechanism operation, then the adjustment lever operability is improved, but the drive-side cam may rotate relative to the driven-side cam in the locked state causing unintended unlocking
Solution Approach 1:
The drive-side cam is designed to be rotatably supported during operation to enable locking and unlocking, but in the locked state, the flat butt section of the convex section contacts the driven-side cam to prevent relative rotation. This dynamic design allows both operational flexibility and locked state stability.
3Adaptability or versatility
If the inner diameter of the outer column is made to expand and contract elastically for telescopic adjustment, then the position adjustment range is improved, but the structural strength of the column is reduced
Solution Approach 1:
The outer column incorporates an elastic portion with a slit that allows the column to expand and contract elastically for telescopic adjustment. This flexible design enables position adjustment while maintaining sufficient structural strength through the elastic properties of the material and geometry.
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 configuration effectively prevents the drive-side cam from rotating relative to the driven-side cam in the locked state, reducing the risk of unintended unlocking and maintaining a smooth operating force for the adjustment lever, even under impact, while also reducing wear and operational force.
Implementation Method 1
the inclined sliding sections slide over one another
Implementation Method 2
only the tip-end butt sections come into contact with one another
Data Source
AI summary
Construction is achieved of a cam device that is able to effectively prevent a drive-side cam from rotating relative to a driven-side cam in a locked state. Tip-end butt sections 63 are provided on the outer-diameter side portions of tip-end surfaces 41a (40a) of convex sections of one of drive-side convex sections 34a of the drive-side cam surface 31a and driven-side convex sections 36a of the driven-side cam surface 32a, and tip-end concave sections 64 that are further recessed in the axial direction than the tip-end butt sections 63 are provided on the inner-diameter side portions of the one convex sections. In the locked state, only the tip-end butt sections 63 come in contact with the tip-end surfaces 40a (41a) of the other convex sections of the drive-side convex sections 34a and the driven-side convex section 36a.