Windshield Wiper Phase Displacement for Collision Avoidance
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Solution Overview
Problem
Dual-motor opposite-direction windshield wiper systems face collisions due to manufacturing and electronic tolerances, leading to increased safety distance and reduced harmonic operation, which increases stress and current consumption.
Innovation Solution
A defined phase displacement is introduced between the wiping movements of the two wipers driven by reversing motors via a lever mechanism, where one wiper leads in the first direction and lags in the second, reducing the risk of collision by spreading the wiping movement courses and allowing a smaller minimum distance between wiper blades.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a safety distance is increased between wiper blades to prevent collisions, then collision risk is reduced, but harmonic wiper operation deteriorates and stress increases
Solution Approach 1:
The patent applies preliminary action by intentionally introducing a defined phase displacement (e.g., 5-15 degrees) between the wiping movements of the two wipers before collision can occur. This pre-planned phase difference ensures that even with manufacturing tolerances, the wiper blades maintain safe separation during their wiping cycles, eliminating the need for excessive safety distances while preventing collisions.
Solution Approach 2:
The patent changes the temporal parameter of the wiping operation by introducing a controlled phase displacement between the two wipers. This parameter modification allows the wipers to operate with smaller minimum distances while maintaining collision-free operation, thereby preserving harmonic operation and reducing stress on the wiper system.
2Reliability
If manufacturing tolerances are reduced to eliminate collision risk, then collision risk is reduced, but device complexity and cost increase
Solution Approach 1:
Instead of relying on tight manufacturing tolerances, the patent introduces a preliminary phase displacement that proactively compensates for tolerance variations. This approach shifts the collision prevention strategy from passive tolerance control to active temporal separation, maintaining reliability without increasing manufacturing precision requirements.
Solution Approach 2:
The patent changes the operational parameter (phase angle) rather than the manufacturing parameter (tolerance). By controlling the phase displacement between wipers through the drive mechanism, the system achieves collision-free operation with standard manufacturing tolerances, avoiding the need for expensive high-precision manufacturing.
3Length of moving object
If wiper levers are positioned closer together to improve aesthetics and reduce vehicle width, then vehicle width is reduced, but collision risk increases due to tolerance accumulations
Solution Approach 1:
The patent introduces a preliminary phase displacement that ensures wiper blades are temporally separated during their wiping cycles. This pre-planned temporal separation allows the wiper levers to be positioned closer together aesthetically while maintaining collision-free operation, as the phase displacement compensates for the reduced spatial separation.
Solution Approach 2:
By changing the temporal parameter (phase angle) of wiper operation, the patent enables closer positioning of wiper levers without increasing collision risk. The controlled phase displacement ensures that even with reduced minimum distances, the wipers maintain safe separation throughout their wiping cycles.
Data Source
AI summary
In the case of a windshield wiper system with two opposite wipers 1, 2, 4, 5 and two reversing motors 6, 7, the risk of a collision of the wipers can be diminished greatly in that a defined phase displacement is generated between the wiping movements of the two wipers, which are driven in a reversing manner, with the aid of the lever mechanism 8 associated with the reversing motors, and said phase displacement is arranged so that the one wiper is leading relative to the other wiper in the first wiping direction and lagging in the second wiping direction.