Household appliance
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Solution Overview
Problem
Existing wireless charging solutions for detachable control devices in household appliances cause eddy current heating and inefficiency due to magnetic flux passing through metal panels, especially with limited button sizes.
Innovation Solution
The implementation of primary and secondary induction coils with specific magnetic conductors, such as central columns and flat plates, to concentrate and direct magnetic flux, reducing leakage and heating, and enhancing charging efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a primary induction coil is integrated on the rear side of the button operation surface for wireless charging, then the detachable control device can be charged wirelessly, but magnetic flux passes through the metal panel causing eddy current heating and energy loss
Solution Approach 1:
A magnetic conductor layer is introduced as an intermediary between the primary induction coil and the metal panel. This magnetic conductor serves as a mediator that guides and concentrates the magnetic flux through the button structure, preventing it from passing through the metal panel and generating eddy currents, thereby reducing energy loss while maintaining wireless charging functionality
Solution Approach 2:
The magnetic conductor is specifically positioned and shaped to concentrate magnetic flux locally within the button area. By creating a localized magnetic flux path through the magnetic conductor layer and button structure, the solution ensures that magnetic flux is confined to where it is needed for charging while preventing it from affecting the surrounding metal panel
2Ease of operation
If magnetic flux is used to charge the detachable control device through the metal panel, then wireless charging is achieved, but the metal panel heats up due to induced eddy currents
Solution Approach 1:
The magnetic conductor layer acts as a protective intermediary between the induction coil and the metal panel. It redirects the magnetic flux through a controlled path that avoids the metal panel, thereby preventing the panel from heating up while still enabling wireless charging through the button
Solution Approach 2:
The magnetic conductor changes the path and distribution parameters of the magnetic flux. By introducing this layer with specific magnetic properties, the flux density and direction are modified to concentrate flux through the button while minimizing flux exposure to the metal panel, thus controlling temperature rise
3Area of moving object
If the button size and operation surface are limited, then the design maintains compactness and aesthetic appearance, but eddy current losses are exacerbated
Solution Approach 1:
The magnetic conductor is designed with specific local geometry (extending beyond the coil area) to maximize flux concentration within the limited button area. This local optimization ensures that even with a small button surface, the magnetic flux is efficiently guided through the button structure rather than dispersing into the metal panel
Solution Approach 2:
The button structure is designed as a composite system incorporating the magnetic conductor layer, the button body with non-conductive operation surface, and the induction coil. This composite structure optimizes the magnetic flux path while maintaining the compact button design, preventing eddy currents in the metal panel despite the limited button area
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 effectively suppresses eddy current losses and improves wireless charging efficiency by tightly surrounding the magnetic flux between the coils, maintaining a metallic appearance while ensuring efficient charging of detachable control devices.
Implementation Method 1
a primary induction coil is provided on the rear side of the operation surface, and a secondary induction coil is correspondingly provided in the detachable control device, so that the detachable control device can be charged by means of the magnetic flux conducted between the primary induction coil and the secondary induction coil
Implementation Method 2
The secondary induction coil is provided with a second magnetic conductor, which at least contains a second central column located in the center of the secondary induction coil and a second flat plate carrying the secondary induction coil, by means of the first magnetic conductor and the second magnetic conductor, the conducted magnetic flux tightly surrounds the primary induction coil and the secondary induction coil
Data Source
AI summary
A household appliance contains a metal panel and a detachable control device. A button is embedded in the metal panel, the button has a non-conductive operation surface, and a primary induction coil is provided on the rear side thereof. A secondary induction coil is provided in the control device and is provided with a first magnetic conductor, which contains a first central column, a first flat plate carrying the primary induction coil and a first sidewall encircling the periphery of the primary induction coil. The secondary induction coil is provided with a second magnetic conductor, which contains a second central column located in the center of the secondary induction coil and a second flat plate carrying the secondary induction coil. A conducted magnetic flux tightly surrounds the primary and secondary induction coils, so as to avoid occurrence of eddy current heating in the metal panel and improve the charging efficiency.