Wiper Blade Damping Web Segmentation via Material Hardness

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Solution Overview

Problem

Existing wiper strip designs with damping webs lack efficient methods for controlled separation and manufacturing flexibility, leading to challenges in modifying spring characteristics and maintaining manufacturing tolerances.

Innovation Solution

The damping ribs are designed with separable predetermined breaking points, allowing for separation by tearing or cutting, using a different material that supports crack propagation, and featuring tailored end faces for precise separation, which can be integrated into the manufacturing and assembly lines.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If damping webs are made from the same material as the rest of the wiper strip, then manufacturing is simpler, but controlled separation becomes difficult

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidcontrolled separation precision
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The damping webs are manufactured from a different material (softer material with Shore hardness of approximately 30 Shore A) compared to the rest of the wiper strip (approximately 60 Shore A). This local material differentiation enables controlled crack propagation and separation at predetermined breaking points while maintaining overall manufacturing efficiency through co-molding or post-attachment processes.

Inventive Principle:
Principle #3Local quality

2Stability of the object's composition

If damping webs are integrally connected to both contact shoulders and header, then structural stability is improved, but separation complexity increases

Engineering Contradiction:
Improvestructural stabilityVSAvoidseparation process complexity
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The damping webs are designed with predetermined breaking points that segment the integral connection into separable sections. The separation line runs in the longitudinal direction of the damping webs, allowing them to be torn or cut into segments (typically separated approximately up to the tilting web) while maintaining structural stability during operation. The free end face is given a shape tailored to the position of the separation point to facilitate controlled separation.

Inventive Principle:
Principle #1Segmentation

3Ease of operation

If damping webs use material supporting crack propagation, then separation ease is improved, but material selection flexibility decreases

Engineering Contradiction:
Improveseparation easeVSAvoidmaterial selection flexibility
Core Design Contradiction:
Ease of operationVSAdaptability or versatility

Solution Approach 1:

The patent specifies using a softer material with Shore hardness of approximately 30 Shore A for the damping webs, compared to approximately 60 Shore A for the rest of the wiper strip. This parameter change in material hardness enables crack propagation and easy separation while maintaining sufficient structural stability during operation. The material is typically a synthetic rubber or blend that balances these opposing requirements.

Inventive Principle:
Principle #35Parameter changes

4Manufacturing precision

If free end face has tailored shape for separation point, then separation precision is improved, but manufacturing complexity increases

Engineering Contradiction:
Improveseparation point precisionVSAvoidmolding complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The free end face of the damping webs is given a shape tailored to the position of the separation point during the molding process. This preliminary shaping creates notches or specific geometries (such as concave contours, sharp fillets, or curly bracket shapes) that concentrate stress and guide crack propagation to the intended separation points. This approach integrates the separation feature into the manufacturing process rather than adding it as a separate operation.

Inventive Principle:
Principle #10Preliminary action

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 approach enables cost-effective and precise separation of damping webs, allowing for flexible design modifications and improved manufacturing efficiency while maintaining small tolerances, enhancing the wiper strip's performance and manufacturing process.

Implementation Method 1

the damping webs are torn at the point of separation and separated approximately up to the tilting web. To this end, it is advantageous for the damping webs to consist of a different material from the rest of the wiper strip, specifically a material that supports the propagation of the crack.

Methodology Applied
Scientific EffectCrack propagation: Fracture Mechanics

Data Source

PatentEP2152550B1Wiper blade and method for the production thereof
Publication Date: 2013.06.19 ROBERT BOSCH GMBH
  • EP2152550B1 patent drawingFigure 1~2
  • EP2152550B1 patent drawingFigure 3~4
  • EP2152550B1 patent drawingFigure 5~8

AI summary

The invention relates to a wiper blade (20, 58), the wiper lip (24, 60) of which is integrally molded onto a head strip (44, 66) in the region of abutment shoulders (28, 64) via a tilted wedge (32, 74), wherein, in the longitudinal grooves (34, 36, 76, 78) formed by the tilted wedge (32, 74), the abutment shoulders (28, 64) and the adjacent parts of the head strip (44, 66), attenuation wedges (38, 40, 70) are provided that extend transversely to said grooves, said attenuation wedges being integrally molded onto the adjacent parts of the longitudinal grooves (34, 36, 76, 78) in a bonded manner. The invention provides for the attenuation wedges (38, 40, 70) to be separated in the longitudinal direction thereof.