Polyurethane Wiper Blade Rubber for Curved-Surface Dirt Removal
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Solution Overview
Problem
Existing wiper blades lack sufficient followability to curved surfaces and wiping performance, particularly in removing particulate dirt, due to issues with contact uniformity and stability.
Innovation Solution
A blade rubber composed of polyurethane with specific elastic modulus ranges (E'(1) 12.0 to 18.0 MPa at 1×10^-3 Hz and E'(2) 530 to 1500 MPa at 1×10^4 Hz) is used, combined with a support member and wiper arm, to enhance followability and wiping performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional rubber materials are used for wiper blades, then the structure is simple and easy to manufacture, but the followability to curved surfaces and wiping performance are insufficient
Solution Approach 1:
The patent applies composite materials by combining polyurethane elastomer with specific viscoelastic properties (storage elastic modulus E' between 0.1-10 MPa at 1×10^-3 Hz and 100-500 MPa at 1×10^4 Hz) as the blade rubber material. This composite approach resolves the contradiction by achieving both excellent followability to curved surfaces and high wiping performance through the specific viscoelastic characteristics of polyurethane, while maintaining manufacturing simplicity.
Solution Approach 2:
The patent applies parameter changes by precisely controlling the viscoelastic parameters of the blade rubber, specifically the storage elastic modulus at different vibration frequencies. By optimizing E' at 1×10^-3 Hz for followability and at 1×10^4 Hz for wiping performance, the patent resolves the contradiction between curved surface adaptability and dirt removal efficiency without complicating the material composition.
2Reliability
If high-hardness rubber is used at the tip to improve wiping performance, then dirt scraping ability increases, but contact uniformity and followability to curved surfaces deteriorate
Solution Approach 1:
The patent applies parameter changes by optimizing the frequency-dependent viscoelastic parameters of a uniform polyurethane material. The storage elastic modulus is controlled to be 0.1-10 MPa at low frequency (1×10^-3 Hz) for excellent contact uniformity and followability, while reaching 100-500 MPa at high frequency (1×10^4 Hz) for effective dirt scraping. This resolves the contradiction by using a single material with tailored dynamic properties rather than multi-material construction.
Solution Approach 2:
The patent applies dynamics by utilizing the time-frequency dependent viscoelastic behavior of polyurethane. The material exhibits soft, compliant behavior at low frequencies (good for curved surface followability) and stiff, rigid behavior at high frequencies (good for dirt scraping). This dynamic property transformation within a single material resolves the contradiction between contact uniformity and wiping performance.
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 stable contact and effective dirt scraping on curved surfaces, preventing slipping-through and maintaining long-term cleaning efficiency.
Implementation Method 1
an elastic member which comprises polyurethane... in environment of a temperature of 8°C, when it is assumed that E'(1) represents a storage elastic modulus at a vibration frequency of 1 x 10^-3[Hz] and E'(2) represents a storage elastic modulus at a vibration frequency of 1 x 10^4[Hz]
Data Source
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AI summary
This blade rubber has a high level of an ability to follow various shapes of surfaces to be wiped and excellent wiping performance. In a blade rubber that is made of an elastic member containing polyurethane and cleans the surface of a member to be cleaned by bringing a part of the elastic member into contact with the surface of the member to be cleaned, when the storage elastic modulus of the blade rubber at a vibration frequency of 1 × 10-3 Hz in an environment of 8°C is E'(1), and the storage elastic modulus at a vibration frequency of 1 x 104 Hz is E'(2), E'(1) is 12.0 to 18.0 MPa, and E'(2) is 530 to 1500 MPa.