A frictional damper with linear actuator
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Solution Overview
Problem
Existing washing and drying machine dampers exhibit wide tolerance ranges in friction force, leading to inconsistent energy absorption, noise, and increased storage costs, with the inability to adjust damping force levels to suit specific machine cycles.
Innovation Solution
A friction damper with a tubular hollow body and a damping rod, featuring a friction unit with adjustable spacing between stationary and slidable pressure elements, controlled by a linear actuator, allowing precise adjustment of damping force through a sliding mechanism and push-button switches.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the inner radius of the friction member is adjusted to change friction force, then the energy absorption can be modified, but the tolerance range remains wide (±20% or higher) leading to inconsistent performance
Solution Approach 1:
The invention changes the physical state of the friction member from rigid to compliant by introducing a compliant layer between the friction member and the rod. This allows continuous adjustment of the contact pressure and friction force through controlled deformation of the compliant layer, achieving precise friction force control with minimal tolerance variation.
Solution Approach 2:
The compliant layer acts as an intermediary element between the friction member and the rod. It mediates the force transmission by deformable contact, allowing precise control of the friction force through the layer's mechanical properties rather than direct rigid contact, thereby reducing tolerance sensitivity.
2Adaptability or versatility
If dampers with varying friction forces are stored to meet different cycle requirements, then adaptability to different cycles is improved, but storage costs significantly increase
Solution Approach 1:
The invention makes the damper dynamic by enabling real-time adjustment of the friction force through actuation of the linear actuator. This allows a single damper to adapt to different cycle requirements (washing, rinsing, spinning) by changing its damping characteristic, eliminating the need to store multiple dampers with fixed different friction forces.
Solution Approach 2:
The damper is designed with multi-functionality through the adjustable friction mechanism. A single damper unit can perform multiple functions across different operating cycles by adjusting the friction force level, replacing the need for multiple specialized dampers and reducing inventory requirements.
3Reliability
If the damping force is high for general cycles, then vibration absorption is improved, but during high-speed spinning the damping force cannot be reduced or eliminated
Solution Approach 1:
The damper transitions from a static friction force to a dynamic one that can be adjusted in real-time. During high-speed spinning, the linear actuator reduces or eliminates the friction force by adjusting the compliant layer deformation, while during washing cycles it maintains high friction for vibration absorption, achieving cycle-specific optimization.
4Force
If the friction member is tightly gripped to increase friction force, then energy dissipation is improved, but the tolerance range in friction force generation increases
Solution Approach 1:
Instead of changing the geometric parameter (inner radius) to adjust friction force, the invention changes the contact pressure parameter through the compliant layer deformation. This allows friction force adjustment while maintaining consistent geometric dimensions, reducing the tolerance accumulation and improving friction force precision.
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
Enables precise control over damping force levels, reducing noise and vibrations, stabilizing the machine, and minimizing storage costs by ensuring consistent energy absorption across different machine cycles.
Implementation Method 1
During the reciprocating motion, the rod comes into contact with the cylindrical friction member and dissipates its energy
Implementation Method 2
a compliant layer extending along a longitudinal direction of the friction member and having a first end and a second end. The actuator is in contact with the compliant layer at the first end of the compliant layer and is movable relative to the friction member along the longitudinal direction of the friction member between a first position and a second position
Data Source
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AI summary
Embodiments of the present invention relates to friction damper (100) for washing or drying machines comprising a tubular hollow body (110) and a damping rod (120) arranged coaxially with respect to one another for moving along each other telescopically, wherein the damping rod (120) has an outer diameter less than an inner diameter of the hollow body (110).The hollow body (110) further comprises the hollow body (110) comprises a holder (130) for holding a friction unit (200). The friction unit (200) comprises a unit body (210); a friction member (220) inside the unit body (210) to which the damping rod (120) is slidably coupled for generating a friction force onto the damping rod (120); a stationary pressure element (230); a slidable pressure element (240) surrounding at least another part of the friction member (220); a linear actuator (260) fixed to the unit body (210) for providing a sliding motion to the slidable pressure element (240).