Dishwasher Door Motor Current Monitoring for Spring Failure Detection
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Solution Overview
Problem
Household dishwashers lack effective monitoring systems to prevent uncontrolled door opening due to potential damage in the spring-pretensioned cable system, posing a safety risk to users.
Innovation Solution
A control unit within the dishwasher monitors the motor current of the door opening and closing device, evaluating its functionality by comparing the detected motor current with a reference curve, allowing for the detection of non-functional states such as broken springs or cables, and outputs warnings or deactivates the door mechanism to prevent accidental opening.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a separate sensor or switch is added to monitor the door spring, then the reliability of door monitoring is improved, but the device complexity increases
Solution Approach 1:
The control unit is designed to perform multiple functions: it controls the washing machine operation and simultaneously monitors the door spring condition by evaluating motor current. This multi-functionality eliminates the need for separate monitoring sensors while maintaining reliable door monitoring through the existing control unit's analytical capabilities.
Solution Approach 2:
The patent replaces mechanical monitoring sensors with an electrical current analysis system. By monitoring the motor current characteristics during door closing operation, the system detects spring condition without physical contact sensors, thereby reducing mechanical complexity while improving reliability.
2Device complexity
If motor current monitoring is implemented, then the need for additional sensors is eliminated, but the measurement precision requirements increase
Solution Approach 1:
The control unit continuously monitors motor current during door closing operation and compares it against predetermined thresholds. This feedback mechanism allows the system to detect spring failures by identifying deviations in current consumption patterns, achieving reliable detection through continuous electrical parameter analysis rather than requiring high-precision single-point measurements.
Data Source
AI summary
A household dishwasher includes a dishwasher cavity, a door attached pivotably to the dishwasher cavity, a door opening and closing device for automated opening and closing of the door, and a control unit designed to actuate the door opening and closing device. The control unit is designed to detect a motor current of a drive element of the door opening and closing device and to evaluate the detected motor current as to whether the door opening and closing device is functional or non-functional.