Drum Ball Balancer Viscosity Tuning for Vibration Control
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Solution Overview
Problem
Washing machines experience vibration and noise issues during high-speed drying due to unbalanced drum rotation, as the center of gravity does not coincide with the center of rotation, and conventional ball balancers are sensitive to temperature and gap variations, leading to ineffective vibration and noise control.
Innovation Solution
The washing machine employs ball balancers with adjustable viscosity viscous oil and a controlled gap between the racer and balls, optimizing the dynamic balance by varying the viscosity of the oil in proportion to the gap, maintaining effective vibration and noise reduction within specific viscosity and gap ranges (100-1000 cSt and 0.5-3.0 mm).
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the gap between the inner wall of the racer and the steel balls is small, then the ball balancer attains correct position more accurately, but the deviation in vibration increases considerably due to temperature sensitivity
Solution Approach 1:
The patent applies parameter changes by varying the viscosity of the viscous oil in the ball balancer to compensate for temperature variations. When temperature changes cause the gap to vary, the oil viscosity is adjusted accordingly to maintain proper damping characteristics and vibration control, thus resolving the contradiction between position accuracy and vibration stability.
2Speed
If the gap between the inner wall of the racer and the steel balls is large, then the ball balancer rapidly attains correct position and vibration is decreased, but noise increases when oil viscosity is low
Solution Approach 1:
The patent uses parameter changes by adjusting the viscous oil properties based on the gap size. When the gap is enlarged to improve balancing speed, the oil viscosity is increased to prevent excessive noise generation, thereby maintaining both fast response and low noise operation.
3Manufacturing precision
If the gap is expanded to control vibration and noise, then manufacturing error tolerance increases, but it becomes difficult to control vibration and noise characteristics
Solution Approach 1:
The patent introduces the viscous oil as an intermediary element between the racer and the balls. This intermediary substance provides damping and control mechanisms that compensate for manufacturing errors in the gap, allowing larger tolerances while maintaining effective vibration and noise control through the oil's viscous properties.
4Device complexity
If conventional ball balancers are used with fixed viscosity oil, then the structure is simple, but the balancer is sensitive to temperature and gap variations leading to ineffective vibration and noise control
Solution Approach 1:
The patent applies dynamics by making the oil viscosity variable rather than fixed. The viscous oil's viscosity changes in response to temperature and gap variations, allowing the ball balancer to adapt to different operating conditions and maintain effective vibration and noise control without requiring complex mechanical adjustments.
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
This solution effectively maintains dynamic balance and reduces vibration and noise in washing machines by optimizing the relationship between the gap and viscosity of the viscous oil in the ball balancers, ensuring proper operation across varying conditions.
Implementation Method 1
the viscosity of the viscous oil is varied in proportion to a gap between the racer and the balls
Implementation Method 2
the steel balls compensate for the above unbalance, thus allowing the drum to maintain its dynamic balance
Data Source
AI summary
A drum type washing machine includes an annular recess formed in the front cover such that the annular recess is located immediately adjacent to a wall of the drum body; and a ball balancer including an annular-shaped racer having a closed internal space in which a plurality of balls and viscous oil are accommodated. The annular-shaped racer includes first and second injection molded members joined to each other to form the closed internal space. The ball balancer is supported by the annular recess formed in the front cover of the drum, and the ball balancer is configured to be attachable to the drum with the viscous oil and the plurality of balls already in the ball balancer.