Variable damping shock absorber

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Solution Overview

Problem

Existing drum washing machine shock absorbers fail to effectively adjust damping force according to varying vibration amplitudes during different stages of the washing process, leading to increased noise and potential machine instability.

Innovation Solution

A variable damping shock absorber is designed with friction plates of varying thickness or friction coefficients along the sleeve, allowing the damping force to adjust based on the position of the piston rod within the sleeve, ensuring appropriate damping for different stages of the washing process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If a shock absorber with larger damping force is used to suppress vibrations in large amplitude conditions, then the vibration suppression effect is improved, but the noise of the washing machine increases in small amplitude conditions

Engineering Contradiction:
Improvevibration suppressionVSAvoidnoise
Core Design Contradiction:
Stability of the object's compositionVSObject-affected harmful factors

Solution Approach 1:

The shock absorber employs multiple friction plates with different friction coefficients arranged in sequence along the piston rod. As the piston moves during different vibration amplitudes, different friction plates engage, providing dynamically adjusted damping forces. This allows the system to adapt to varying vibration conditions without manual intervention, resolving the contradiction between vibration suppression and noise reduction.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

Different sections of the piston rod are equipped with friction plates having different friction coefficients. The friction plates are arranged from the bottom to the top of the piston rod with progressively different friction characteristics. This local differentiation allows the shock absorber to provide appropriate damping for specific vibration conditions, enabling effective vibration suppression while controlling noise levels.

Inventive Principle:
Principle #3Local quality

2Object-affected harmful factors

If a shock absorber with smaller damping force is used to reduce noise in small amplitude conditions, then the noise is reduced, but the vibration in large amplitude conditions cannot be suppressed

Engineering Contradiction:
ImprovenoiseVSAvoidvibration suppression
Core Design Contradiction:
Object-affected harmful factorsVSStability of the object's composition

Solution Approach 1:

The shock absorber employs multiple friction plates with different friction coefficients arranged in sequence along the piston rod. As the piston moves during different vibration amplitudes, different friction plates engage, providing dynamically adjusted damping forces. This allows the system to adapt to varying vibration conditions without manual intervention, resolving the contradiction between vibration suppression and noise reduction.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

Different sections of the piston rod are equipped with friction plates having different friction coefficients. The friction plates are arranged from the bottom to the top of the piston rod with progressively different friction characteristics. This local differentiation allows the shock absorber to provide appropriate damping for specific vibration conditions, enabling effective vibration suppression while controlling noise levels.

Inventive Principle:
Principle #3Local quality

3Device complexity

If a constant damping force is used in the shock absorber, then the structure is simple, but the damping cannot be adjusted for different operating stages

Engineering Contradiction:
ImprovestructureVSAvoiddamping adjustment
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The shock absorber divides the friction damping function into multiple segments by using several friction plates with different friction coefficients. Each friction plate corresponds to a specific vibration amplitude range. This segmentation allows the system to provide different damping characteristics for different operating stages while maintaining a relatively simple overall structure without complex control systems.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The shock absorber employs multiple friction plates with different friction coefficients arranged in sequence along the piston rod. As the piston moves during different vibration amplitudes, different friction plates engage, providing dynamically adjusted damping forces. This allows the system to adapt to varying vibration conditions without manual intervention, resolving the contradiction between vibration suppression and noise reduction.

Inventive Principle:
Principle #15Dynamics

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 a practical and cost-effective means to adjust damping forces dynamically, effectively reducing vibrations and noise across different load and speed conditions, ensuring optimal performance during washing and dewatering processes.

Implementation Method 1

the friction plate 8' and the piston rod 7' move relatively. Due to the friction principle, the piston rod 7' produces a damping force on the sleeve 6'

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP3249088B1Variable damping shock absorber
Publication Date: 2020.09.23 QINGDAO HAIER DRUM WASHING MACHINE CO LTD
  • EP3249088B1 patent drawingFigure 1
  • EP3249088B1 patent drawingFigure 2
  • EP3249088B1 patent drawingFigure 3

AI summary

The present disclosure discloses a variable damping shock absorber comprising a sleeve and a piston rod, one end of the sleeve being an opening and the other end being closed, one end of the piston rod being inserted into through the opening and being slideably provided in an axial direction inside the sleeve, at least two sets of friction plates are arranged in the axial direction between an inner wall of the sleeve and an outer wall of the piston rod, the friction plate is fixed in the axial direction with the inner wall of the sleeve, and a sliding friction force between each friction plate set and the outer wall of the piston rod gradually decreases from the closed end to the opening end of the sleeve. Specifically, each set of the friction plates has a same thickness in a radial direction of the sleeve and has a different friction coefficient of a surface of one side which is in contact with the outer wall of the piston rod, and the friction coefficient decreases from the closed end to the open end of the sleeve. Alternately, each set of friction plates are of a same material, and a thickness of the friction plates in a radial direction of the sleeve is different, and the thickness of each set of friction plates decreases from the closed end to the open end of the sleeve. The shock absorber of the present disclosure is simple and practical, and the cost is low, and the structure can ensure that the damping force is variable under different load and the rotational speed conditions.