Vehicle Wiper Pivot Shaft Energy Absorption

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Solution Overview

Problem

Modern windshield wiper systems face issues with pivot shafts being prone to damage from external forces, leading to potential replacement needs due to stress concentration features.

Innovation Solution

Incorporating an energy-absorbing feature, such as a biasing element or fluid chamber, into the wiper arm pivot shafts to absorb energy from external forces, allowing the pivot shafts to move away from the force and potentially return to their initial position without requiring component replacement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a stress concentration feature is added to the pivot shaft holder to move away from external force, then the pivot shaft holder can withstand external force, but the pivot shaft holder must be replaced after absorbing the force

Engineering Contradiction:

Improveresistance to external forceVSAvoidcomponent replacement requirement

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The patent applies this principle by making the energy-absorbing feature a replaceable component rather than integrating it into the main pivot shaft holder. The energy-absorbing feature is designed as a separate, sacrificial element that can be easily replaced after absorbing external force, while the expensive pivot shaft holder itself is preserved and reused.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent segments the pivot shaft holder into distinct functional components: the main structural pivot shaft holder and the separate energy-absorbing feature. This segmentation allows the energy-absorbing feature to be independently replaced without replacing the entire pivot shaft holder assembly, resolving the contradiction between strength and reliability.

Inventive Principle:

Principle #1Segmentation

2Strength

If the pivot shaft holder is designed to move away from external force, then damage to the pivot shaft is reduced, but the pivot shaft holder structure becomes more complex

Engineering Contradiction:

Improveprotection of pivot shaftVSAvoidpivot shaft holder structure

Core Design Contradiction:

StrengthVSDevice complexity

Solution Approach 1:

By separating the energy-absorbing function into a distinct component rather than integrating it into the pivot shaft holder structure, the patent protects the pivot shaft while keeping the holder structure itself simple and unchanged.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The energy-absorbing feature acts as an intermediary element between the external force and the pivot shaft holder. It absorbs the impact force before it reaches the holder, protecting the pivot shaft without requiring modifications to the holder's structural design.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If an energy-absorbing feature is integrated into the pivot shaft, then the pivot shaft can absorb external force energy, but the manufacturing complexity increases

Engineering Contradiction:

Improveenergy absorption capabilityVSAvoidmanufacturing process

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The energy-absorbing feature is manufactured as a separate component and then installed in the pivot shaft assembly, rather than being integrated into the pivot shaft itself. This segmentation allows each component to be manufactured using standard processes, avoiding the need for complex integrated manufacturing.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The energy-absorbing feature serves as an intermediary component that provides the energy absorption capability without requiring modifications to the pivot shaft's manufacturing process. It is a separate element that can be independently manufactured and then assembled into the pivot shaft assembly.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 energy-absorbing feature effectively mitigates damage from external forces, enabling the windshield wiper system to maintain functionality without needing component replacement, ensuring prolonged system durability and reduced maintenance costs.

Implementation Method 1

the energy-absorbing feature is a biasing element configured such that the second shaft portion is biased away from the first shaft portion. This allows the second shaft portion to move toward the first shaft portion along the pivot axis when the external force is applied.

Methodology Applied

Scientific EffectElasticity: Elasticity

Implementation Method 2

Other embodiments include a spring that extends along a structural support member between pivot shaft holders of first and second pivot shafts.

Methodology Applied

Scientific EffectSpring: Spring

Implementation Method 3

Another embodiment utilizes a shear pin between the pivot shaft holder and a mounting feature. The shear pin fractures when the applied force has a predetermined magnitude, allowing the pivot shaft to move away from the applied force along the pivot axis.

Methodology Applied

Scientific EffectFracture Mechanics: Fracture Mechanics

Data Source

PatentUS9187062B2Vehicle windshield wiper system with energy-absorbing feature

Publication Date: 2015.11.17 GM GLOBAL TECHNOLOGY OPERATIONS LLC

AI summary

A windshield wiper system for a vehicle includes a wiper arm pivot shaft having a pivot axis extending through the pivot shaft. An energy-absorbing feature is arranged to absorb energy of an external force applied to the wiper arm pivot shaft. The energy-absorbing feature enables the wiper arm pivot shaft to move away from the external force.