Cooktop Knob Assembly With Jointed Shaft Misalignment Compensation
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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 the alignment of knobs and knob rings is critical for proper function and user convenience.
Innovation Solution
A fire power controlling knob assembly with a joint that absorbs positional errors between the knob and valve shafts, allowing independent operation of the knob ring for timer settings and displaying firepower or timer time, while maintaining insulation and preventing gas leakage, using a Hall sensor and magnet for accurate rotation sensing and a push-and-turn mechanism to prevent accidental rotation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a knob is directly connected to a valve shaft without a joint, 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, serving as a mediator that absorbs positional errors and enables reliable connection despite assembly tolerances.
2Reliability
If a joint is added to absorb positional errors, then knob alignment and operation reliability improve, but device complexity increases
Solution Approach 1:
The connection system is segmented into distinct functional components: the joint body, the first shaft coupling portion connected to the valve shaft, and the second shaft coupling portion connected to the knob shaft. This segmentation allows each component to be optimized independently while collectively solving the misalignment problem.
3Ease of operation
If the knob ring is made independently operable for timer settings, then user convenience improves, but device complexity increases
Solution Approach 1:
The knob ring is designed with multi-functionality: it can be independently operated to set timer duration, and the display device on the knob ring can display both firepower level and timer time. This allows a single component to perform multiple functions, improving user convenience while managing complexity.
4Loss of information
If a display device is coupled to the knob ring, then information display capability improves, but insulation and coupling stability become challenging
Solution Approach 1:
A display housing is introduced as an intermediary component between the knob ring and the display device. This display housing provides both mechanical coupling to stabilize the display device on the knob ring and electrical insulation to prevent short circuits, solving both coupling stability and insulation challenges.
5Measurement precision
If a Hall sensor and magnet are used for rotation sensing, then measurement precision improves, but device complexity increases
Solution Approach 1:
The mechanical rotation sensing mechanism is replaced with a Hall sensor and magnet system. The Hall sensor detects the position of the magnet on the rotating component, providing precise rotation sensing through electromagnetic fields rather than mechanical contact, thereby improving measurement precision.
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 knob operation, enhances appearance quality, improves user convenience by allowing precise timer and firepower control, reduces the risk of gas leakage, and simplifies assembly and manufacturing by absorbing positional errors and maintaining accurate rotation sensing, thus preventing operation defects and safety hazards.
Implementation Method 1
using a Hall sensor and magnet for accurate rotation sensing
Data Source
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.