Knob Assembly Joint Design for Gas Valve Alignment and Flow Control
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Solution Overview
Problem
Existing cooking appliances face issues with knob misalignment due to assembly tolerance, leading to appearance and operation defects, and lack of fine adjustment for gas flow rate without separating the appliance.
Innovation Solution
A knob assembly with a joint that absorbs position errors between the knob and valve shaft, allowing for stable operation and fine adjustment of gas flow rate, featuring a Hall sensor and magnet for accurate rotation sensing and display of firepower levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a knob is directly connected to a valve assembly, then the structure is simple, but assembly tolerance causes misalignment and operation failure
Solution Approach 1:
A joint component is introduced as an intermediary between the knob and valve assembly. This joint includes a first shaft coupling portion connected to the valve shaft and a second shaft coupling portion connected to the knob shaft, with a joint spring that absorbs position errors and assembly tolerances, thereby preventing misalignment while maintaining structural simplicity
Solution Approach 2:
The joint spring changes its elastic parameter (compression/extension) to absorb position errors between the knob and valve assembly. By allowing the spring to compress or extend within its elastic range, the system accommodates assembly tolerances without causing misalignment or operation failure
2Ease of operation
If the gas flow rate is controlled by adjusting the valve, then the firepower can be adjusted, but fine adjustment without separating the appliance is not possible
Solution Approach 1:
The joint spring automatically absorbs position errors and maintains proper alignment between the knob and valve shaft during gas flow rate adjustment. This self-adjusting mechanism enables fine control of gas flow without requiring the user to separate or disassemble any components
3Reliability
If the knob is pushed and rotated for safety control, then gas leakage is prevented, but the knob cannot rotate freely
Solution Approach 1:
The joint spring provides dynamic compliance to the knob assembly, allowing the knob to rotate freely during normal operation while maintaining proper alignment. The spring's elastic properties enable smooth rotation without restricting movement, while the push-to-operate safety mechanism remains effective
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 improves the reliability and appearance quality of the cooking appliance by stabilizing knob operation, reducing the risk of gas leakage, and enhancing user convenience with precise control and display of firepower and timer settings.
Implementation Method 1
a Hall sensor and magnet for accurate rotation sensing
Data Source
Figure 1
Figure 2~3
Figure 4
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.