Integrated Motor Accelerometer for Washing Machine Unbalance Detection
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Solution Overview
Problem
Existing solutions for detecting load unbalance in washing machines with synchronous electric motors are complex, costly, and prone to inaccuracies due to the separation of motor and control board components, requiring extensive wire assemblies and unreliable accelerometer-based methods.
Innovation Solution
An electronic control board integrated with a piezoelectric-film accelerometer directly supported by the synchronous electric motor stator continuously monitors the washing machine tank's acceleration, reducing vibrations and oscillations by controlling motor speed and minimizing wire assemblies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the electronic control board and accelerometer are separated from the motor and positioned near the rotary drum, then the detection of load unbalance can be performed, but complex and expensive wire assemblies are required to connect these components
Solution Approach 1:
The patent combines the electronic control board and accelerometer into an integrated unit that is directly mounted on the motor housing. This merging eliminates the need for separate wire assemblies to connect these components to the motor, reducing both complexity and cost while maintaining detection functionality through the motor housing as a mounting structure.
Solution Approach 2:
The motor housing serves multiple functions: it provides structural support for the motor, acts as a mounting surface for the integrated control board and accelerometer, and serves as a reference frame for vibration detection. This multi-functionality eliminates the need for separate mounting structures and connection wiring.
2Reliability
If an accelerometer is positioned near the rotary drum with separate wiring, then load unbalance detection is possible, but the wire assembly costs increase maintenance expenses
Solution Approach 1:
By integrating the accelerometer and control board directly onto the motor assembly, the patent eliminates separate wire assemblies that would require installation and maintenance. This reduces maintenance costs as the integrated unit can be serviced as a single assembly, and wire-related failures are eliminated.
3Measurement precision
If the accelerometer output voltage is processed with amplifiers and suitable circuits positioned separately, then the detection can be performed, but the device complexity and wire requirements increase
Solution Approach 1:
The patent integrates the signal processing circuitry directly with the accelerometer on the motor housing. This consolidation eliminates the need for separate amplifiers and processing circuits positioned elsewhere in the system, reducing wire requirements and overall device complexity while maintaining measurement precision through direct signal processing at the source.
4Reliability
If separate wire assemblies are used to connect the accelerometer to the electronic control board, then the detection system can function, but noise is induced on the connecting wire assembly reducing measurement reliability
Solution Approach 1:
By integrating the accelerometer and control board into a single unit mounted on the motor housing, the patent eliminates the connecting wire assembly that would introduce noise. The direct integration ensures clean signal transmission without the interference problems associated with long wire runs, thereby improving measurement accuracy while maintaining system functionality.
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
The solution provides accurate and continuous detection of load unbalance, reducing maintenance costs and vibrations, while ensuring precise operation and compact device design.
Implementation Method 1
incorporating an accelerometer, in particular a piezoelectric-film accelerometer
Data Source
AI summary
A detecting device of unbalance conditions, particularly for washing machines (1) and similar household appliances comprising a rotary drum (2a) supported by a tank (2) and activated by a synchronous electric motor (3) with an internal stator (5) having corresponding windings fixedly mounted on a central axis (10). The detecting device comprises an electronic control board (18) for the synchronous motor (3) associated with the stator (5) and incorporating at least one accelerometer (51) to constantly monitor the acceleration of said tank (2) and indirectly the unbalance of said washing machine (1) and the unbalance of a load comprised in the rotary drum (2a).