Switchable damper
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Solution Overview
Problem
Existing dampers in washing machines lack a simple and cost-effective solution to switch between friction damping and freewheeling modes, leading to inefficient noise reduction and vibration control during spin cycles, as they require complex and expensive controllable damping systems.
Innovation Solution
A switchable damper with a switching unit that can be easily toggled between a blocking arrangement for friction damping and a freewheel arrangement, utilizing a piston with a friction lining and a shifting actuator to manage the transition, allowing for direct friction damping and freewheeling functions without continuous damping at high speeds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a controllable damping system is used to switch between friction damping and freewheeling modes, then the noise and vibration control efficiency is improved, but the device complexity and manufacturing cost increase
Solution Approach 1:
The damper system dynamically switches between two distinct operational modes (blocking arrangement for friction damping and freewheeling arrangement) based on operational requirements. The switching unit enables the system to adapt its damping characteristics in real-time, providing high damping during acceleration and low damping during high-speed rotation, thereby resolving the contradiction between noise control and system complexity
Solution Approach 2:
The damper operates in periodic cycles, alternating between blocking and freewheeling arrangements according to the operational phase. During washing cycles, the blocking arrangement is engaged for noise reduction; during spin cycles, the freewheeling arrangement is engaged for high-speed operation. This periodic switching achieves effective noise and vibration control without requiring a continuously complex controllable system
2Object-affected harmful factors
If continuous friction damping is applied during high-speed spin cycles, then vibration control is maintained, but noise emissions and vibrations increase
Solution Approach 1:
The system dynamically adjusts its damping characteristics by switching between blocking and freewheeling arrangements. During high-speed spin cycles, the freewheeling arrangement is activated, which maintains sufficient vibration control through the damper's mechanical design while significantly reducing noise emissions by eliminating continuous friction contact
Solution Approach 2:
The damper changes its operational parameters by transitioning between two distinct states: the blocking arrangement with high friction damping for vibration control, and the freewheeling arrangement with reduced friction for low-noise high-speed operation. This parameter change allows the system to optimize performance for different operational conditions, reducing noise during spin cycles while maintaining vibration control capability
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 switchable damper effectively prevents excessive drum movement and noise by activating friction damping before critical speeds and deactivating it during spin cycles, reducing manufacturing and operational complexity while maintaining robustness and cost-effectiveness.
Implementation Method 1
The friction lining is blocked by the piston on which it is arranged. Displacement of the friction lining relative to the housing and/or the plunger is blocked. In the blocking arrangement, the damping function of the switchable damper is activated, i.e., switched on. The switchable damper functions as a friction damper.
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
A switchable damper (1) comprises a housing (2) having a longitudinal axis (3), a ram (4) that can be displaced along the longitudinal axis (3), a piston (20) arranged between the housing (2) and the ram (4) , a friction lining (21) arranged on the piston (20) and a switching unit (23) which is arranged between a blocking arrangement in which the piston (20) is blocked with respect to displacement along the longitudinal axis (3) and a freewheel arrangement in which the Piston (20) is released with respect to a displacement along the longitudinal axis (3), is switchable.