Wiper Blade Spoiler Guide Rail Design

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Solution Overview

Problem

Existing joint-free wiper blades face challenges in optimizing contact pressure and flexibility to accommodate various vehicle window curvatures, often requiring complex assembly processes and material combinations that affect weight and performance.

Innovation Solution

A spoiler designed as a separate component with guide rails surrounding the head rail, featuring a second longitudinal channel for elastic bending and accommodating a second spring rail, allowing for adjustable spring stiffness and simplified assembly by eliminating the need for end caps and enabling optimal contact pressure adaptation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Weight of moving object

If the spoiler is made as a separate component with guide rails, then the flexibility and weight are improved, but the device complexity increases

Engineering Contradiction:
Improveweight of spoilerVSAvoidcomplexity of spoiler structure
Core Design Contradiction:
Weight of moving objectVSDevice complexity

Solution Approach 1:

The spoiler is divided into a base structure and separate guide rails that can be extruded onto the spoiler. This segmentation allows the guide rails to be made from harder material for lateral support while the base spoiler remains lighter and more flexible, resolving the contradiction between weight reduction and structural complexity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The guide rails are nested within the spoiler structure, with the rails being extruded onto the spoiler surface. This nesting approach integrates the harder guide rails into the lighter spoiler body, achieving both weight reduction and enhanced lateral support without proportionally increasing overall complexity.

Inventive Principle:
Principle #7Nested doll (Nesting)

2Strength

If the guide rails are made of harder material, then the lateral support is improved, but the flexibility for assembly decreases

Engineering Contradiction:
Improvelateral support of guide railsVSAvoidflexibility for assembly
Core Design Contradiction:
StrengthVSEase of operation

Solution Approach 1:

The guide rails are segmented from the base spoiler and can be extruded onto the spoiler surface. This allows the rails to be made of harder material for lateral support while the base spoiler remains flexible, resolving the contradiction between strength and assembly flexibility.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The guide rails are pre-extruded onto the spoiler in a flexible state, allowing easy assembly. After assembly, the rails provide their intended lateral support strength. This preliminary action in a softer state resolves the contradiction between ease of assembly and final structural strength.

Inventive Principle:
Principle #10Preliminary action

3Ease of operation

If the second longitudinal channel is added to the spoiler, then the flexibility and assembly ease are improved, but the manufacturing complexity increases

Engineering Contradiction:
Improveease of assemblyVSAvoidmanufacturing complexity of spoiler
Core Design Contradiction:
Ease of operationVSEase of manufacture

Solution Approach 1:

The second longitudinal channel is integrated into the spoiler manufacturing process through co-extrusion or post-extrusion techniques. This merging of the channel creation into the existing manufacturing flow minimizes additional complexity while enabling the flexibility benefits for assembly.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The second longitudinal channel serves multiple functions: it provides flexibility for guide rail assembly, accommodates additional spring rails for contact pressure adjustment, and maintains structural integrity. This multi-functionality justifies the manufacturing complexity by delivering multiple benefits from a single structural feature.

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

4Stress or pressure

If the spring rails are made with variable cross-section, then the contact pressure optimization is improved, but the manufacturing precision requirements increase

Engineering Contradiction:
Improvecontact pressure distributionVSAvoidprecision of spring rail cross-section
Core Design Contradiction:
Stress or pressureVSManufacturing precision

Solution Approach 1:

The spring rails have variable cross-sections with different widths and heights at different locations along their length. This local quality variation optimizes the contact pressure distribution across the wiper blade, providing higher stiffness where needed and lower stiffness at ends, thereby resolving the contradiction between pressure optimization and manufacturing complexity.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The cross-sectional parameters of the spring rails (width and height) are varied continuously or in steps along the length of the rail. This parameter change approach allows precise control of the stiffness profile to match the contact pressure requirements of different application scenarios, resolving the contradiction between optimized pressure distribution and manufacturing precision requirements.

Inventive Principle:
Principle #35Parameter changes

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 enhances flexibility and weight reduction while ensuring optimal contact pressure distribution and lateral support, allowing for a wide range of application-specific modifications and improved wiping quality.

Implementation Method 1

a spring-elastic support element with an elongate cross-section running transversely to the wiper lip

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

the guide rails can be elastically bent outwards during assembly of the wiper strip

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Data Source

PatentEP2015971B1Wiper blade
Publication Date: 2011.07.27 ROBERT BOSCH GMBH
  • EP2015971B1 patent drawingFigure 1~2
  • EP2015971B1 patent drawingFigure 3~4
  • EP2015971B1 patent drawingFigure 5~7

AI summary

The invention is based on a wiper blade (12) with a wiper strip (14) which has a wiper lip (16) and a head strip (20) which is integrally formed on said wiper lip and, in a first longitudinal channel (26), has a supporting element in the form of a spring rail (18) with a flat cross section, and has a spoiler (22, 38, 46) on that side which faces away from the wiper lip (16). It is proposed that the spoiler (22, 38, 46) surrounds the head strip (20) on its longitudinal sides by means of guide rails (40).