Wiper Blade Expanded Interval Aerodynamic Design
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Solution Overview
Problem
Vehicle wiper blades experience deteriorated wiping characteristics due to increased lift and drag from travel wind, leading to a water-conducting phenomenon where rainwater is drawn back into the wiping area by negative pressure created by eddies behind the blade.
Innovation Solution
The wiper blade design features a rubber holder with a top wall, front wall, and back wall, where the interval between the back wall and the blade rubber expands towards the center, and a cover member with a through hole to guide travel wind onto the back-side of the blade, reducing eddy formation and negative pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a fin-shaped cover member is attached to the rubber holder to generate down force from travel wind, then wiping characteristic during vehicle travel is enhanced, but eddies are generated on the back-face side causing negative pressure that draws rainwater back into the wiping range
Solution Approach 1:
A flow guide member is introduced as an intermediary component between the fin-shaped cover member and the blade rubber. This mediator redirects the travel wind flow to pass through the interval between the back wall and blade rubber, preventing eddy formation while maintaining the down force generation. The flow guide member acts as a mediator that transforms the harmful eddy flow into a useful directed flow that exits at the front face side.
Solution Approach 2:
The invention converts the harmful eddy flow and negative pressure into a beneficial directed flow. By using the flow guide member to redirect the travel wind, the previously harmful back-face flow is transformed into a controlled flow that passes through the interval and exits at the front, eliminating the water-conducting phenomenon while preserving the aerodynamic down force.
2Object-affected harmful factors
If the interval between back wall and blade rubber is expanded toward the center portion, then wind flow is facilitated reducing eddies, but the structural integrity of the rubber holder may be compromised
Solution Approach 1:
The rubber holder is designed with non-uniform interval spacing, where the interval between the back wall and blade rubber is expanded specifically toward the center portion of the blade rubber. This localized modification allows wind flow facilitation in the critical area where eddies form, while maintaining adequate structural thickness at the end portions where strength is most needed for attachment and support.
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 design enhances the wiping characteristic by facilitating wind flow between the blade and holder, reducing eddy generation and preventing water-conducting phenomena, ensuring effective rainwater removal during vehicle travel.
Implementation Method 1
the travel wind, which flows on an upper side of the wiper blade along the cover member, generates an eddy or eddies on a back-face side of the wiper blade
Implementation Method 2
a negative pressure is caused on the back-face side of the wiper blade by the eddy
Data Source
AI summary
An interval between an inner face 31c1 of a back wall 31c in a rubber holder 31 and a blade rubber 32 is formed so as to become gradually expanded with respect to an interval between an inner face 31b1 of a front wall 31b and the blade rubber 32 as being directed toward a center portion from both longitudinal-directional end portions of the rubber holder 31. Also, an interval between an inner face of each back wall in a pair of covers coupled to the both longitudinal-directional end portions of the rubber holder 31 and the blade rubber is formed so as to become gradually expanded with respect to an interval between the inner face of the front wall and the blade rubber as being directed toward the center portion from both longitudinal-directional end portions of the cover. Accordingly, a flow of travel wind during a travel of a vehicle is facilitated between the rubber holder 31 and the blade rubber 32 or between the covers and the blade rubber 32.