Plastic Wiper Shaft Positioning Element

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Solution Overview

Problem

Existing windshield wiper devices face challenges in precise positioning and cost-effective manufacturing due to the limitations of metal-based positioning elements, which can be costly and inflexible in design.

Innovation Solution

The use of a non-metallic positioning element, specifically a thermoplastic material, with features like elevations, tooth-like structures, and attachment methods such as crimping and gluing, allows for improved precision and reduced manufacturing costs by compensating for tolerances and simplifying assembly processes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a metal-based positioning element is used, then the connection strength and durability are improved, but the manufacturing cost increases and design flexibility decreases

Engineering Contradiction:
Improveconnection strengthVSAvoidmanufacturing cost
Core Design Contradiction:
StrengthVSEase of manufacture

Solution Approach 1:

The patent replaces expensive metal positioning elements with inexpensive plastic positioning elements that can be manufactured at low cost through injection molding. The plastic material is sufficient for the application requirements, eliminating the need for costly metal components while maintaining adequate functionality.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent changes the material parameter from metal to plastic, which fundamentally alters the manufacturing process from metalworking to plastic molding. This parameter change enables mass production through injection molding, significantly reducing manufacturing costs while providing sufficient connection strength for the positioning function.

Inventive Principle:
Principle #35Parameter changes

2Strength

If a metal-based positioning element is used, then the connection strength and durability are improved, but the design flexibility and functionality decrease

Engineering Contradiction:
Improveconnection strengthVSAvoiddesign flexibility
Core Design Contradiction:
StrengthVSAdaptability or versatility

Solution Approach 1:

The patent changes the material parameter from metal to plastic, enabling complex geometries and integrated features that would be difficult or expensive to manufacture in metal. The plastic material allows for injection molding of intricate shapes, including integrated attachment features and tolerance compensation elements.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent employs plastic material that can be combined with metal components in composite assemblies. The plastic positioning element works in conjunction with metal parts like the wiper shaft and bearing bush, creating a hybrid system that leverages the advantages of both materials - the design flexibility of plastic and the strength of metal.

Inventive Principle:
Principle #40Composite materials

3Ease of manufacture

If the positioning element is made as a single piece, then the manufacturing process is simplified, but the assembly difficulty increases

Engineering Contradiction:
Improvemanufacturing process simplicityVSAvoidassembly difficulty
Core Design Contradiction:
Ease of manufactureVSEase of operation

Solution Approach 1:

The patent divides the positioning element into multiple separate components, such as the positioning element itself and attachment elements like clips or tabs. This segmentation allows each component to be manufactured independently using simple injection molding processes, and then assembled together through straightforward snap-fit or interference-fit connections.

Inventive Principle:
Principle #1Segmentation

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 solution enables more precise positioning of the wiper shaft, reduces manufacturing costs, and allows for various design variations with improved functionality, resulting in a better connection between the positioning element and the wiper shaft, enhancing the overall performance and efficiency of the wiper device.

Implementation Method 1

The positioning element is shrunk onto the wiper shaft, in particular by means of a heating element

Methodology Applied
Scientific EffectHeating: Heating

Implementation Method 2

The positioning element is adhesively connected, in particular glued, to the wiper shaft

Methodology Applied
Scientific EffectAdhesive bonding: Adhesive

Data Source

PatentEP3798068B1Wiper device and method for manufacturing a wiper device
Publication Date: 2023.04.19 ROBERT BOSCH GMBH
  • EP3798068B1 patent drawingFigure 1
  • EP3798068B1 patent drawingFigure 2
  • EP3798068B1 patent drawingFigure 3

AI summary

The invention relates to a wiper device (10), in particular a windshield wiper device (12), and to a method for manufacturing such a wiper device (10), comprising a wiper shaft (30) rotatably mounted in a bearing bushing (40) and a positioning element (50) designed to secure the position of the wiper shaft (30) in the bearing bushing (40). It is proposed that the positioning element (50) be made of plastic.