Wiper Motor Double Cam Plate Transient Voltage Control
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Solution Overview
Problem
The wiper system generates a transient voltage when the wiper blade enters a stop position after a multifunctional switch is turned off, causing damage to connected elements and a jerking phenomenon due to the sudden drop in electromotive force applied to the wiper motor.
Innovation Solution
An apparatus with a double cam plate system that connects and disconnects internal contact points of the wiper motor's P-terminal and E-terminal, using a center plate to gradually decrease the electromotive force to 0 V, preventing a sharp voltage drop and eliminating the need for a Varistor, thus reducing manufacturing costs and minimizing the impact on the wiper blade during stoppage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the wiper motor is compulsorily stopped by applying 0 V to the P-terminal after the multifunctional switch is turned off, then the wiper blade stops at the parking position, but a transient voltage is generated causing damage to connected elements and a jerking phenomenon
Solution Approach 1:
The cam plate is designed to connect the P-terminal and E-terminal in advance before the motor is compulsorily stopped. This preliminary connection ensures that the motor has a path to discharge accumulated energy and gradually reduce current, preventing transient voltage generation when the switch is turned off while maintaining reliable parking position control
2Manufacturing precision
If the P-terminal and E-terminal are connected by the cam plate to stop the wiper blade at the parking position, then the stop position is accurate, but a transient voltage is generated when the motor is compulsorily stopped with high-voltage power applied
Solution Approach 1:
The cam plate serves as an intermediary mechanism that provides a gradual transition path for electrical connection. By designing the cam plate to connect P-terminal and E-terminal through a controlled mechanical motion, the system creates an intermediate state that allows smooth current reduction, preventing abrupt voltage changes while maintaining precise parking position control
3Speed
If the electromotive force is sharply decreased to 0 V when the motor stops, then the motor stops quickly, but a transient voltage is generated causing element damage and jerking phenomenon
Solution Approach 1:
The system transitions from a static abrupt stop mechanism to a dynamic gradual stop mechanism. The cam plate's rotational motion dynamically controls the connection between P-terminal and E-terminal, creating a time-varying electrical path that gradually reduces current. This dynamic approach allows the motor to stop quickly in terms of positional response while smoothly reducing electrical stress, preventing transient voltage and jerking phenomena
Data Source
AI summary
Disclosed is an apparatus for controlling a wiper motor for a wiper system. The wiper motor includes a double cam plate rotated by rotational force of a motor, and internal contact points formed by a P-terminal and an E-terminal disconnected/connected by the double cam plate. The double cam plate includes a first cam plate and a second cam plate for connecting the P-terminal and the E-terminal, and a center plate between the first and second cam plates. The apparatus includes a circuit line connecting the P-terminal with an off terminal of a low relay, and a control unit turning off the low relay simultaneously when the P-terminal and the E-terminal connected by the first cam plate are disconnected when a multifunctional switch is turned off. The apparatus decreases electromotive force applied to the wiper motor while the center plate is in contact with the P-terminal.