Cooktop Knob Assembly With Tolerance-Absorbing Joint Coupling
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Solution Overview
Problem
Existing cooking appliance knobs face misalignment issues due to assembly tolerance, leading to degraded appearance quality and operation failures, particularly in composite cooking appliances with multiple burners, where precise alignment of knobs and valve shafts is crucial for smooth operation and safety.
Innovation Solution
A fire power controlling knob assembly with a joint that absorbs positional errors between the knob and valve shaft, allowing independent operation of the knob ring for timer settings and incorporating a Hall sensor for accurate rotation sensing, ensuring reliable and safe operation while maintaining a constant spacing between components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a knob is directly connected to a valve shaft in a cooking appliance, then the structure is simple, but assembly tolerance causes misalignment and operation failure
Solution Approach 1:
A joint is introduced as an intermediary component between the knob and valve shaft. This joint includes a joint body with a first shaft coupling portion connected to the valve shaft and a second shaft coupling portion connected to the knob shaft, allowing it to absorb positional deviations and prevent misalignment while maintaining reliable operation.
2Manufacturing precision
If a joint is added between the knob and valve shaft to absorb assembly tolerance, then alignment and operation reliability are improved, but device complexity increases
Solution Approach 1:
The joint serves as a mediator that absorbs assembly tolerances and positional deviations between the knob and valve shaft. It includes coupling portions for both components and incorporates elastic elements to accommodate misalignment, thereby improving manufacturing precision without requiring complex adjustment mechanisms.
Solution Approach 2:
The joint incorporates elastic elements (springs) that provide dynamic compensation for positional deviations. The elastic elements allow the joint to adapt to assembly tolerances through elastic deformation, maintaining proper alignment while absorbing shocks and vibrations during operation.
3Ease of manufacture
If the knob structure is simplified for ease of manufacture, then production cost decreases, but the ability to absorb assembly tolerance is reduced
Solution Approach 1:
The joint is designed as a separate intermediary component that can be manufactured independently with standard tolerances. It absorbs assembly tolerance deviations through its elastic elements and geometric design, allowing the knob and valve shaft to be manufactured separately with easier tolerances while maintaining final assembly precision.
Solution Approach 2:
The joint incorporates elastic elements (springs) that provide beforehand cushioning for assembly tolerance deviations. These elastic elements are pre-installed in the joint to compensate for potential misalignment before final assembly, ensuring proper positioning without requiring high-precision manufacturing of individual components.
4Measurement precision
If a Hall sensor is added to sense knob rotation for accurate firepower control, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The Hall sensor replaces mechanical contact-based sensing mechanisms with a non-contact magnetic field sensing system. The sensor detects the rotational position of the knob through magnetic field changes, eliminating the need for mechanical encoders or contact switches, thereby improving measurement precision while reducing mechanical complexity.
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 stabilizes the knob operation, improves appearance quality by maintaining precise alignment, enhances user convenience with integrated timer and firepower display, and reduces the risk of gas leakage and safety accidents by precise control and sensing.
Implementation Method 1
a Hall sensor for accurate rotation sensing
Data Source
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AI summary
A knob assembly includes a front panel, a knob located at a front side of the front panel and configured to rotate based on operation by a user, a knob shaft that is coupled to the knob and that extends through the front panel, a supporting pipe that receives the knob shaft and that supports the knob shaft, the supporting pipe being configured to maintain a position relative to the front panel, a valve configured to control supply of gas to the appliance, a valve shaft connected to the valve and configured to control the valve to adjust a flow rate of gas based on rotation of the valve shaft, and a joint that couples the knob shaft to the valve shaft and that is configured to transfer at least one of a rotational motion or a linear motion of the knob shaft to the valve shaft.