Ice Dispenser Duct Door Motor Control for Low-Noise Actuation
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Solution Overview
Problem
Conventional ice dispenser mechanisms, such as solenoids and motors, generate undesirable noise and consume significant power during duct door actuation, increasing complexity and cost.
Innovation Solution
A motor-driven duct door system that uses an electrical signal with varying slopes (increasing, constant, and decreasing) to smoothly and quietly actuate the duct door, reducing noise and power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a solenoid is used to actuate the duct door, then the duct door can be actuated, but undesirable noise is generated and significant power is consumed
Solution Approach 1:
The patent replaces the solenoid (electromagnetic actuator) with a DC stepper motor, which uses precise electronic control to drive the duct door. This substitution eliminates the noisy clicking and buzzing sounds characteristic of solenoids while maintaining the ability to actuate the door reliably.
Solution Approach 2:
The patent implements variable voltage control of the DC stepper motor, dynamically adjusting the electrical signal parameters during the dispensing cycle. The controller applies different voltage levels at different stages: higher voltage to initiate movement, reduced voltage to maintain position, and controlled voltage reduction to prevent noise during closing, thereby eliminating harmful noise while preserving actuation functionality.
2Ease of operation
If a solenoid is used to actuate the duct door, then the duct door can be actuated, but significant power is consumed
Solution Approach 1:
The patent implements variable voltage control of the DC stepper motor, dynamically adjusting the electrical signal parameters during the dispensing cycle. The controller applies different voltage levels at different stages: higher voltage to initiate movement, reduced voltage to maintain position, and controlled voltage reduction to prevent noise during closing, thereby eliminating harmful noise while preserving actuation functionality.
Solution Approach 2:
The patent uses periodic pulsing of the DC stepper motor rather than continuous power application. The motor receives electrical impulses only when needed to change the door position, and power is reduced or eliminated when the door is held in position or during idle periods, significantly reducing overall power consumption compared to continuous solenoid operation.
3Ease of operation
If a DC stepper motor is used to actuate the duct door, then the duct door can be actuated, but significant vibration is created causing undesirable noise
Solution Approach 1:
The patent implements variable voltage control of the DC stepper motor, dynamically adjusting the electrical signal parameters during the dispensing cycle. The controller applies different voltage levels at different stages: higher voltage to initiate movement, reduced voltage to maintain position, and controlled voltage reduction to prevent noise during closing, thereby eliminating harmful noise while preserving actuation functionality.
4Ease of operation
If a constant-power AC motor is used to actuate the duct door, then the duct door can be actuated, but numerous additional elements are required increasing complexity and cost
Solution Approach 1:
The patent replaces the constant-power AC motor system with a DC stepper motor controlled by a microcontroller. This substitution eliminates the need for mechanical cam rollers, cam followers, and position detection switches, as the stepper motor's inherent step-by-step motion control and the microcontroller's digital position tracking provide the same functionality with fewer parts.
Solution Approach 2:
The microcontroller serves multiple functions: it controls the DC stepper motor actuation, tracks door position through pulse counting, manages the variable voltage output, and coordinates with the ice dispensing logic. This single component replaces multiple dedicated elements (motor controller, position switches, timing circuitry) that would be required with a constant-power AC motor system.
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 system achieves smoother duct door movement, reduces noise, and minimizes power requirements during ice dispensing by variably driving the motor with specific electrical signal profiles.
Implementation Method 1
a motor configured to actuate the duct door between the open position and the closed position
Implementation Method 2
The controller can be configured to adjustably drive the motor such that an electrical signal applied to the motor varies during a dispensing cycle
Data Source
AI summary
An ice dispensing assembly in an appliance and a method of controlling a duct door in an ice dispensing assembly is provided. A duct door is actuated to dispense ice using a motor. The motor can be variably driven using an electrical signal having a plurality of different levels or slopes during the actuation of the duct door. The electrical signal can have an increasing slope when the duct door is actuated into an open position. When the duct door is held in the open position, a constant electrical signal can be applied to the motor. The constant value can be lower than a peak value of the increasing slope of the electrical signal. To return the duct door to a closed position, an electrical signal having a decreasing slope can be applied to the duct door motor.