Washing Machine Friction Damper With Air-Spring Imbalance Damping
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Solution Overview
Problem
Drum washing machines with existing friction dampers fail to effectively absorb imbalances and reduce ground and tensile forces, leading to potential misalignment and noise due to inadequate direction- and amplitude-dependent damping.
Innovation Solution
A friction damper design featuring a gas-tight damper housing with a movable friction lining carrier, creating an air cushion for enhanced damping in the compression direction and relying on frictional forces in the tension direction, with air release valves to control pressure and venting means to maintain uniform damping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If friction dampers are used in drum washing machines, then vibration reduction is achieved, but the damping force is insufficient to effectively absorb imbalances and reduce ground forces
Solution Approach 1:
The damper system dynamically adapts its damping characteristics based on movement direction and amplitude. The friction lining carrier moves relative to the piston, engaging friction elements only during upward movement while allowing free wheeling during downward movement, creating direction-dependent damping that effectively absorbs imbalances.
Solution Approach 2:
Different regions of the damper provide different damping characteristics. The compression chamber provides air spring damping during downward movement, while the friction elements provide friction-based damping during upward movement. This local differentiation of damping properties enables effective imbalance absorption while reducing ground forces.
2Force
If friction elements act on the inner wall of the damper housing, then damping force is generated, but the damping is not amplitude-dependent leading to inadequate performance across different vibration magnitudes
Solution Approach 1:
The system transitions from static to dynamic damping characteristics. The friction lining carrier is displaced by the piston during operation, causing friction elements to engage only when the displacement exceeds a certain threshold. This creates amplitude-dependent damping where larger vibrations engage the friction elements while smaller vibrations rely on air spring damping.
Solution Approach 2:
The patent replaces constant mechanical friction damping with a dynamic system that switches between air spring damping and friction damping based on amplitude. The movable friction lining carrier acts as a threshold mechanism that activates friction elements only when necessary, providing adaptive damping across different vibration magnitudes.
3Object-affected harmful factors
If the damper housing is designed to reduce ground forces, then floor vibrations are reduced, but the washing machine may be displaced due to high frictional forces in the pulling direction
Solution Approach 1:
The damper system employs asymmetric damping characteristics for compression and rebound directions. During downward movement (compression), the air spring provides gentle damping that reduces ground forces. During upward movement (rebound), friction elements engage to provide controlled damping. This asymmetry prevents excessive frictional forces that could displace the washing machine while still reducing floor vibrations.
Solution Approach 2:
The system changes the damping parameter based on movement direction. The friction lining carrier position relative to the piston determines whether friction elements are engaged. This parameter change enables the system to provide appropriate damping levels for each direction, reducing ground forces without creating excessive frictional forces that would cause displacement.
4Adaptability or versatility
If a freewheel mechanism is implemented, then the friction lining and damping force become effective only from a certain deflection, but the damping transition may cause instability
Solution Approach 1:
The air spring in the compression chamber acts as an intermediary between the friction elements and the piston. During the transition phase when the friction lining carrier is not yet engaged, the air spring provides smooth damping that prevents instability. This intermediary mechanism ensures a stable transition between free wheeling and friction-based damping modes.
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 solution provides adaptive damping that reduces ground forces and prevents washing machine misalignment by amplifying damping in downward movements and maintaining stability through amplitude-dependent damping, reducing noise and floor vibrations.
Implementation Method 1
an air cushion is formed to generate a damping force that goes beyond the frictional force caused by the friction elements
Implementation Method 2
at least one friction element acting on the inner surface of the damper housing to generate a damping force
Implementation Method 3
air release valves are arranged that can be controlled via the movement of the friction lining carrier and connect the compression chamber with the environment during the upward movement
Data Source
Figure 1~3
Figure 4~5
Figure 6
AI summary
A friction damper for drum washing machines with direction- and amplitude-dependent damping has in the housing part between the bottom of the damper housing (1) and the friction elements (7) held in a friction lining carrier (6) arranged to be axially movable on the damper piston (2) between a first and second stop a compression space (10) for an air spring that forms after a freewheeling phase in the compression direction (arrow A) to generate a damping force that goes beyond the frictional force effected by the friction elements. In the compression direction, an increased damping force dependent on the amplitude and supported by the air spring is thus generated. Air passage openings (9), which can be controlled via the movement of the friction lining carrier, are arranged in the damper piston and connect the compression space with the environment during movement in the direction of tension. The proposed friction damper reduces ground forces and reduces the risk of misalignment.