Knob Joint Assembly for Valve Shaft Misalignment Compensation
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Solution Overview
Problem
In cooking appliances, misalignment of the knob and valve assembly due to manufacturing tolerances and assembly deviations leads to operational failures and a degraded exterior appearance, particularly when multiple burners are used, as the knob and knob ring become misaligned, causing issues with rotation and return functionality.
Innovation Solution
A joint is introduced between the valve shaft and the knob shaft to absorb position errors, allowing for accurate alignment and smooth operation, with a structure that includes a housing, shaft supports, and a spring to maintain the connection angle, eliminating the need for manual adjustment and separate fixing tasks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a rotary shaft is used to connect the knob and valve, then power transmission is achieved, but misalignment occurs due to manufacturing tolerances and assembly deviations
Solution Approach 1:
A joint mechanism is introduced as an intermediary component between the knob shaft and valve shaft. This joint includes a first yoke connected to the knob shaft, a second yoke connected to the valve shaft, and a connector that links the two yokes. The connector allows for angular misalignment compensation, serving as a mediator that absorbs positioning errors from manufacturing and assembly processes while maintaining reliable power transmission.
Solution Approach 2:
The joint mechanism changes the angular parameter relationship between the knob shaft and valve shaft. By allowing the connector to accommodate angular deviations, the system can maintain proper alignment even when manufacturing tolerances cause variations in shaft angles. This parameter flexibility resolves the contradiction between operational reliability and manufacturing precision.
2Manufacturing precision
If manual adjustment is used to correct alignment deviation, then positioning accuracy is improved, but assembly complexity and time increase
Solution Approach 1:
The joint mechanism is designed to self-align and absorb positioning errors automatically during assembly. The connector's structure enables it to accommodate angular misalignments without requiring manual adjustment or complex alignment procedures. This self-service capability improves alignment accuracy while keeping assembly simple and straightforward.
3Device complexity
If the knob is rigidly connected to the valve shaft, then structural simplicity is maintained, but operational failure occurs due to alignment errors
Solution Approach 1:
The rigid connection between the knob shaft and valve shaft is segmented into multiple components: the first yoke, connector, and second yoke. This segmentation allows each component to perform its specific function while collectively providing misalignment compensation. The modular structure maintains relative simplicity while dramatically improving operational reliability by eliminating the single-point failure mode of rigid connections.
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 joint ensures accurate alignment and operation of the knob and knob ring, enhancing the appliance's appearance and functionality by stabilizing the connection between the valve and knob shafts, reducing manufacturing costs, and simplifying assembly processes.
Implementation Method 1
a spring (177) provided between the first shaft support (173) and the second shaft support (175) and configured to provide an elastic force
Data Source
AI summary
A joint, a knob assembly, and an appliance having a joint and a knob assembly are provided. The joint may include a housing, a first shaft support, a second shaft support, and a coupling shaft. A slot having a predetermined width extending in a circumferential direction of the housing and a predetermined length extending in a longitudinal direction of the housing may be formed in the housing. The coupling shaft provided in the second support may include a rotary shaft rotatably inserted into the slot. A stopper may be formed to protrude from an outside of the rotary shaft, and a position of the stopper inside the slot may be changed according to rotation of the rotating shaft. The stopper may be provided in the slot so that the stopper interferes with an inner wall of the housing formed by the slot at a predetermined position.