Segmented Bush for Microwave Oven Shaft Sealing
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Solution Overview
Problem
Microwave ovens with movable elements driven by motors face challenges in preventing microwave leakage, particularly at the shaft transmission regions, where traditional solutions like snap-fitting bushes can be difficult to dismount without damaging the shaft.
Innovation Solution
A bush with multiple segments is used to surround the shaft, mounted between the supporting wall and separator, with a design that allows for easy disassembly and a gap size less than one-fourth of the microwave wavelength to prevent leakage, while the bush's semi-circular parts with recesses and protrusions ensure a tight fit without contacting the shaft.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a bush is mounted onto the shaft to prevent microwave leakage, then microwave safety is improved, but the bush cannot be dismounted without damaging the shaft
Solution Approach 1:
The bush is divided into multiple segments (first bush segment and second bush segment) that can be separated from each other. This segmentation allows the bush to be installed by placing segments around the shaft and joining them, and enables removal by detaching the segments from each other without applying damaging forces to the shaft.
Solution Approach 2:
The bush transitions from a static, permanently fixed component to a dynamic, removable component. The joining and separating mechanisms (such as snap-fit connections, threaded fasteners, or interlocking features) enable the bush to be attached and detached as needed, providing flexibility for maintenance and repair while maintaining microwave sealing when assembled.
2Object-affected harmful factors
If the gap between the bush and shaft is reduced to prevent microwave leakage, then microwave safety is improved, but the shaft rotation is restricted
Solution Approach 1:
The bush is designed with different local properties: the inner surface features a smooth finish with minimal friction to facilitate shaft rotation, while the outer surface or specific sealing zones have enhanced microwave shielding properties. This local differentiation allows the bush to simultaneously enable free shaft rotation and prevent microwave leakage through strategically positioned gaps or shielding materials.
Solution Approach 2:
The gap dimensions are optimized to specific parameter ranges that balance rotation freedom and leakage prevention. By controlling the gap size to be less than one-fourth of the microwave wavelength while maintaining sufficient clearance for rotation, the system achieves both objectives through precise dimensional parameter selection.
3Object-affected harmful factors
If the bush is designed to tightly surround the shaft to prevent microwave leakage, then microwave safety is improved, but the bush cannot be easily installed or removed
Solution Approach 1:
The bush is divided into multiple segments that can be independently handled during installation. The segments are designed with joining features (such as overlapping edges with snap-fit connections, threaded fasteners, or interlocking protrusions and recesses) that allow easy assembly around the shaft and simple disassembly for removal, eliminating the need for forceful installation or destruction of the component.
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 effectively prevents microwave leakage while allowing the shaft to rotate and enabling easy disassembly of the bush, ensuring safe microwave cooking without modifying the existing separator and supporting wall structure, and can be adapted for both microwave and convection cooking.
Implementation Method 1
A bush (12) disposed between the supporting wall (10) and the separator (8), mounted onto the shaft (7) such as to prevent microwave passage through the hole (9) and the opening (11)
Data Source
Figure 1~2
Figure 3~4
AI summary
The present invention relates to an oven (1) which is of the type wherein cooking is performed by microwaves and which comprises a casing (2), a rear wall (3) covering the rear face of the casing (2), a cooking chamber (4) disposed in the casing (2), wherein foods to be cooked are placed, at least one movable element (5) disposed in the casing (2), at least one motor (6) providing the drive of the movable element (5), at least one shaft (7) providing the drive provided by the motor (6) to be transmitted to the movable element (5), a separator (8) separating the volume wherein the movable element (5) and the motor (6) are disposed, having a hole (9) through which the shaft (7) passes, a supporting wall (10) having an opening (11) through which the shaft passes (7), supporting the motor (6) and on which the motor (6) is fixed such as to remain between the rear wall (3) and the supporting wall (10).