Water-bearing domestic appliance
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Solution Overview
Problem
Water-conducting household appliances with moving components, such as dishwashers, face complexity and increased wiring due to the need for additional cabling and position sensors to determine the position of these components during operation.
Innovation Solution
A water-conducting household appliance utilizing a brushless DC motor and a control apparatus that detects the drive current drawn by the motor to ascertain the position of the moving component, eliminating the need for additional cabling and position sensors by using a load apparatus to provide position-dependent resistance and a transmission unit to couple the motor to the component.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a switching cam and signal cable are used to detect the position of moving components, then the position detection accuracy is improved, but the device complexity and wiring outlay increase
Solution Approach 1:
The patent extracts the position detection function from the mechanical switching cam system and integrates it into the electrical motor control system. The control apparatus now performs both motor control and position detection functions, eliminating the need for separate mechanical position sensors and their associated signal cables.
Solution Approach 2:
The patent merges the motor drive function and position detection function into a single integrated control apparatus. The control apparatus uses the existing motor's electrical characteristics (current, voltage, power) to determine component position, combining what were previously separate functions into one unified system.
2Measurement precision
If additional position sensors and cabling are installed to determine component position, then the position identification accuracy is improved, but the manufacturing cost increases
Solution Approach 1:
The patent extracts the position sensing capability from separate hardware components and derives it from the electrical parameters already present in the motor system. This eliminates the need for additional position sensors and their associated cabling, reducing manufacturing costs while maintaining position detection accuracy.
Solution Approach 2:
The motor system serves dual purposes: it both drives the moving component and provides the electrical signals needed for position detection. The control apparatus uses the motor's own electrical characteristics (current draw, power consumption) to determine position, making the system self-sufficient and eliminating the need for separate sensing hardware.
3Reliability
If a mechanical switching cam system is used for position detection, then the position signal is obtained reliably, but the appliance complexity increases
Solution Approach 1:
The patent replaces the mechanical switching cam system with an electrical-based position detection method. Instead of using mechanical cams to trigger position signals, the control apparatus electronically monitors the motor's electrical parameters to determine position, substituting mechanical components with electrical sensing and processing.
Solution Approach 2:
The control apparatus is designed to perform multiple functions: motor control, position detection, and position-based decision-making. This multi-functional approach eliminates the need for separate dedicated position sensing hardware, reducing overall system complexity while maintaining reliable position information.
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 solution reduces the complexity and cost of the appliance while accurately identifying the position of moving components without additional cabling, allowing for precise control and operation of components like spray arms in dishwashers.
Implementation Method 1
an electric motor for moving the component
Implementation Method 2
The load apparatus provides a resistance, which is a function of a position of the moving component and counter to the movement
Data Source
AI summary
A water-conducting household appliance includes a moving component, an electric motor for moving the component, a load apparatus configured to apply a resistance to counter movement of the component as a function of a position of the moving component, and a control apparatus for actuating the electric motor. The control apparatus is configured to detect a drive current drawn which is drawn by the electric motor and is a function of the resistance applied by the load apparatus and to ascertain the position of the moving component as a function of the detected drive current.