Joint and knob assembly and appliance having joint and knob assembly
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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 smooth rotation and return to the original position.
Innovation Solution
A joint is introduced between the valve shaft and the knob shaft, which absorbs position errors and allows for accurate alignment, ensuring the knob and knob ring are assembled correctly, even with manufacturing tolerances, by using a housing with slots and coupling shafts that provide elastic support and rotation, allowing the joint to adjust and maintain the correct angle without manual adjustment.
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 assembly is introduced as an intermediary component between the first shaft (valve shaft) and the second shaft (knob shaft). This joint includes a housing with slots and coupling shafts that can rotate, serving as a mediator to transmit rotational force while compensating for angular misalignment caused by manufacturing tolerances and assembly deviations.
Solution Approach 2:
The joint assembly incorporates dynamic elements including slots that allow radial movement of coupling shafts and springs that provide elastic restoring force. These dynamic features enable the joint to adapt to angular misalignment by allowing the coupling shafts to move radially within the slots while maintaining continuous rotational power transmission.
2Manufacturing precision
If manual adjustment is used to align the knob and valve, then alignment accuracy is improved, but assembly complexity and time increase
Solution Approach 1:
The joint assembly is designed to automatically compensate for angular misalignment without requiring manual adjustment. The coupling shafts can freely move radially within the slots of the housing, and the springs automatically provide the necessary restoring force, allowing the system to self-adjust to the correct alignment during assembly.
Solution Approach 2:
The joint assembly changes the operational parameters by allowing angular deviation from the nominal alignment. Instead of requiring precise fixed alignment, the system accepts a range of angular positions and uses the flexible coupling mechanism to maintain effective power transmission across this parameter variation.
3Strength
If a rigid connection is used between shafts, then structural strength is maintained, but misalignment errors accumulate
Solution Approach 1:
The joint assembly employs a flexible coupling mechanism where coupling shafts can move radially within slots of the housing. This flexibility allows the connection to accommodate angular misalignment while maintaining structural integrity through the rigid housing and spring-based restoring force.
Solution Approach 2:
The connection transitions from a static rigid joint to a dynamic flexible joint. The coupling shafts can move radially within the slots during operation, allowing the connection to adapt to angular misalignment while springs provide continuous restoring force to maintain proper alignment during rotation.
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.