Vehicle Mirror Folding Cam Mechanism Anti-Jitter

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Solution Overview

Problem

The existing electric folding devices for outer rearview mirrors suffer from poor anti-shudder capability, wind noise, and high operational current, leading to folding failures due to inadequate support and increased friction between the mirror substrate and support, especially during fast driving or on rough roads.

Innovation Solution

An electric folding device with a cam assembly that lifts the foundation bed and shell during folding, utilizing a spring and pin shaft to reduce rotation resistance, and a positioning mechanism to ensure accurate assembly, along with a compact design incorporating a large gear and convex blocks for improved coaxiality and mounting accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a gap is reserved between the mirror substrate and the mirror support to reduce frictional resistance during folding, then the folding smoothness is improved, but the anti-shudder capability deteriorates and wind noise increases

Engineering Contradiction:
Improvefolding smoothnessVSAvoidanti-shudder capability
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent applies a spring mechanism that dynamically adjusts the gap between the mirror substrate and mirror support. During normal driving, the spring maintains a small gap for smooth folding. During folding operation, the spring compresses to reduce the gap further, minimizing wind noise and improving folding smoothness without compromising anti-shudder capability

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the gap parameter dynamically using a spring mechanism. The gap varies between a small value during normal operation (maintaining anti-shudder capability) and a larger value during folding (reducing frictional resistance). This parameter change resolves the contradiction by optimizing the gap for different operational states

Inventive Principle:
Principle #35Parameter changes

2Device complexity

If the mirror substrate is solely supported by a pin shaft with a spring sleeve to reduce structure complexity, then the device complexity is reduced, but the anti-shudder capability deteriorates

Engineering Contradiction:
Improvestructure complexityVSAvoidanti-shudder capability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent merges the support function with the folding mechanism by integrating the spring mechanism into the pin shaft assembly. The spring sleeve is mounted on the pin shaft to provide both folding motion and anti-shudder support simultaneously, reducing device complexity while maintaining reliability

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The pin shaft assembly serves multiple functions: it enables folding rotation, provides anti-shudder support through the spring mechanism, and maintains the gap between components. This multi-functionality reduces the need for separate support structures, lowering device complexity while ensuring anti-shudder capability

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Ease of manufacture

If plastic material is used for injection-molded mirror substrate and mirror support to reduce manufacturing cost, then the ease of manufacture is improved, but the operational reliability deteriorates due to aging and friction

Engineering Contradiction:
Improvemanufacturing easeVSAvoidoperational reliability
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent introduces a spring mechanism as an intermediary element between the plastic mirror substrate and mirror support. This spring component compensates for dimensional changes due to aging and reduces friction during operation, thereby improving operational reliability without affecting the ease of manufacturing the plastic components

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The spring mechanism provides beforehand cushioning by pre-compressing to compensate for future aging effects and friction. This anticipatory cushioning ensures that the plastic components maintain proper clearance and operational reliability over time, despite their inherent tendency to age and increase friction

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

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 solution provides a smoother folding process with reduced shaking and wind noise, improved support for the mirror substrate, and lower operational current, resulting in fewer folding failures and enhanced anti-jitter performance.

Implementation Method 1

a spring arranged on the pin shaft in a sleeving mode, and a connecting piece which makes the shell manually rotate relatively to the base, the connecting piece is pressed on the foundation bed by the pre-tightening force of the spring

Methodology Applied
Scientific EffectElastic force: Elasticity

Implementation Method 2

a cam assembly is provided among the connecting piece, the foundation bed and the base, during the electric folding process, driven by the electric driving unit, the cam assembly enables the foundation bed to lift up and rotate along the pin shaft through the relative slide of the cam assembly

Methodology Applied
Scientific EffectCam mechanism: Cam

Implementation Method 3

an electric driving unit used for driving the shell to rotate relatively to the base around the axis of the pin shaft

Methodology Applied
Scientific EffectElectric motor: Linear Motor

Data Source

PatentEP3339098B1Electric folding device for outside rear-view mirror of vehicle
Publication Date: 2020.09.02 NINGBO JINGCHENG CAR IND
  • EP3339098B1 patent drawingFigure 1
  • EP3339098B1 patent drawingFigure 2
  • EP3339098B1 patent drawingFigure 3~4

AI summary

The present disclosure discloses an electric folding device for outer rearview mirror of a vehicle, which includes a shell (6), a foundation bed (3), a base (2), a pin shaft (7), an electric driving unit used for driving the shell (6) to rotate relatively to the base (2) around the axis of the pin shaft (7), a spring (5) arranged on the pin shaft (7) in a sleeving mode, and a connecting piece (4) which makes the shell (6) manually rotate relatively to the foundation bed (3). A cam assembly is provided among the connecting piece (4), the foundation bed (3) and the base (2). During the electric folding process, driven by the electric driving unit, the cam assembly enables the foundation bed (3) to lift up and rotate along the pin shaft (7) through the relative slide of the cam assembly and the elastic force of the spring (5). The device is compact in structure, with better anti-jitter performance, smooth electric folding process, and less folding failure.