Vehicle Door Mirror Vibration Suppression via Ribbed Support Shaft
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Solution Overview
Problem
Existing vehicle door mirror designs with support shafts made of synthetic resin suffer from increased run-out and degraded vibration suppression due to low stiffness, leading to reduced visibility.
Innovation Solution
The support shaft features multiple bosses with tubular portions and ribs extending along their axes, with ribs projectingly provided on the outer periphery, particularly at the base, to effectively abut against mounting holes, enhancing fixation and vibration suppression.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If the support shaft is made of synthetic resin to reduce weight, then weight is reduced, but stiffness becomes low causing large run-out and degraded vibration suppression
Solution Approach 1:
The support shaft is made of synthetic resin (lightweight material) but reinforced with ribs that increase stiffness. This composite structure combines the weight advantage of synthetic resin with the structural strength provided by the rib reinforcements, resolving the contradiction between weight reduction and maintaining sufficient stiffness for vibration suppression
Solution Approach 2:
The ribs are strategically positioned on the support shaft to provide localized reinforcement. Rather than uniformly increasing thickness throughout the support shaft, the ribs concentrate structural strength at critical locations where stiffness is needed most, maintaining weight efficiency while suppressing run-out and vibration
2Object-affected harmful factors
If the rib is provided only on the extremity side of the boss to suppress vibration, then vibration suppression is achieved, but run-out becomes large when using synthetic resin support shafts
Solution Approach 1:
The rib structure extends along the axial dimension of the tubular portion rather than only at the extremity. This dimensional extension of the rib reinforcement along the length of the support shaft provides continuous stiffness support, simultaneously reducing run-out and suppressing vibration in synthetic resin construction
Data Source
AI summary
A vehicle door mirror includes a base member mounted on a side door while having plural mounting holes and plural insertion holes coaxially communicating with the mounting holes, and a mirror housing pivotably supported on a support shaft which has a plurality of bosses, each boss having a tubular portion and ribs extending along an axial direction of the tubular portion. Screw members are inserted through respective ones of the insertion holes and screwed into the tubular portions of the bosses respectively inserted into the mounting holes so that the ribs of each boss abut against an inner peripheral face of the corresponding mounting hole. The ribs are projectingly provided on the outer peripheral face, at least on a base part side, of the corresponding tubular portion. Such arrangement suppresses vibration of the mirror even when the support shaft is made of a synthetic resin.