Damper and washing machine having the same
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Solution Overview
Problem
Conventional washing machines face challenges in effectively damping vibrations, particularly during the spin-dry cycle, where the damping force needs to be adjusted based on rotation speed to prevent noise and damage, but existing solutions are complex and inefficient.
Innovation Solution
A damper system with a switching device that couples and decouples a rod and housing using a solenoid actuator, adjusting frictional force between a friction member and a plunger to match the rotation speed, thereby controlling damping force dynamically.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the damping force is increased to suppress vibrations at low rotation speeds, then vibration suppression is improved, but the damping force becomes excessive at high rotation speeds causing noise and damage
Solution Approach 1:
The damper employs a switching device that dynamically changes the damping mechanism based on rotation speed. At low speeds, the friction member contacts the plunger surface for high damping. At high speeds, the switching device engages a different path that reduces damping force, preventing noise and damage while maintaining vibration suppression at low speeds.
Solution Approach 2:
The damper changes the friction characteristics by switching between two operational states. The switching device alters the contact conditions between friction members and moving parts, effectively changing the damping parameter from high friction engagement at low speeds to reduced friction engagement at high speeds.
2Reliability
If a switching device is added to adjust damping force dynamically, then vibration control is improved, but device complexity increases
Solution Approach 1:
The switching device uses a simple centrifugal mechanism where a weight moves outward due to rotation speed, triggering a latch mechanism that switches between damping states. This dynamic approach achieves adaptive vibration control without requiring complex electronic sensors or actuators.
Solution Approach 2:
The switching device is self-actuating based on the rotation speed of the drum itself. The centrifugal force generated by the rotating damper automatically triggers the switching mechanism, eliminating the need for external control systems, sensors, or power sources.
3Ease of manufacture
If the damper structure is simplified to reduce manufacturing cost, then ease of manufacture is improved, but the ability to adjust damping force for different rotation speeds is reduced
Solution Approach 1:
The damper maintains a relatively simple overall structure with a housing, plunger, and friction members. The adaptability is achieved through a compact switching mechanism integrated into this simple structure, allowing the same basic components to provide both low-speed and high-speed damping characteristics.
Solution Approach 2:
The switching device enables a single damper unit to perform multiple functions: providing high damping force at low rotation speeds and reduced damping force at high rotation speeds. This multi-functionality is achieved through the mechanical switching mechanism that routes the motion differently based on operational conditions.
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 damper system effectively reduces vibrations and noise by adjusting damping force based on rotation speed, allowing for a simpler structure that accommodates varying loads without increasing the machine's size, while minimizing the risk of damage to components.
Implementation Method 1
a friction member arranged between the housing and the plunger to contact an outer circumferential surface of the plunger
Implementation Method 2
When a voltage is applied to the driving member to generate propulsion force to the working rod
Data Source
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AI summary
A washing machine includes a water tub arranged in a case and a damper installed between the case and the water tub for damping vibrations of the water tub. The damper includes a plunger having one end supported on the case; a rod having one end supported on the water tub and the other end movably inserted to the plunger; a housing arranged to wrap around some of the plunger and the rod and including a friction member arranged between the housing and the plunger to contact an outer circumferential surface of the plunger; and a switching device configured to be in a first state in which the rod is coupled to the housing and able to move within the plunger along with the housing and a second state in which the rod is decoupled from the housing and able to move solely within the plunger.