Electromechanical Friction Shock Absorber for Unbalanced Drum Vibration
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Solution Overview
Problem
Existing shock absorbers in washing machines fail to effectively manage unbalanced loads and vibrations due to fixed damping forces, lack of feedback from dynamic systems, and high energy consumption, leading to inefficient vibration control and increased production costs.
Innovation Solution
An electromechanical friction shock absorber with two brake shoes, a stroke sensor, and a coupling system that adjusts damping force based on laundry load and drum movement, using a step motor and friction elements to dynamically control vibrations without tensioning, thereby optimizing energy use and reducing production costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If fixed damping force is used in shock absorbers, then the structure is simple and cost is low, but the vibration control effectiveness is insufficient for unbalanced loads
Solution Approach 1:
The shock absorber uses a step motor to dynamically adjust the friction element's damping force in real-time based on feedback from sensors detecting drum position and acceleration, transforming the fixed damping system into an adaptive dynamic system that optimizes vibration control for varying load conditions
Solution Approach 2:
The system incorporates sensors that continuously monitor drum position and acceleration, feeding this information back to the control unit which adjusts the step motor's friction force accordingly, creating a closed-loop control system that enhances vibration control effectiveness
2Reliability
If magnetic effect is used to produce damping force, then the damping force can be controlled, but electricity consumption increases due to continuous coil power supply
Solution Approach 1:
Instead of continuous power supply, the step motor operates periodically by receiving pulse signals from the control unit only when damping force adjustment is needed, allowing the friction element to maintain damping force through mechanical friction without continuous electrical energy input
Solution Approach 2:
The patent replaces the electromagnetic coil system with a mechanical friction-based damping mechanism actuated by a step motor, substituting electrical energy consumption with mechanical energy storage and transfer through friction surfaces
3Force
If gear system is used to connect motor and friction element, then the system can transmit force, but the speed cannot reach the dynamic system requirements
Solution Approach 1:
The patent removes the gear transmission system entirely, directly coupling the step motor to the friction element through a simplified mechanical connection, eliminating the speed reduction and lag inherent in gear systems while maintaining sufficient force transmission
4Device complexity
If tensioning is not eliminated in the brake screw system, then the structure is simpler, but the step motor torque and power increase significantly
Solution Approach 1:
The patent introduces a coupling system with a coupling washer as an intermediary element between the brake screw and brake shoe, which absorbs and distributes the tensioning forces, preventing direct transmission of high torque to the step motor while maintaining structural integrity
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 real-time control of washing machine drum dynamics, reduces vibrations, optimizes detergent and water usage, and maintains low energy consumption, making it industrially applicable and cost-effective.
Implementation Method 1
an electromechanical friction shock absorber... two brake shoes which contact the friction element... friction force can not be produced by pressing with the spring
Implementation Method 2
a brake screw for clamping and unclamping the brake shoes around the said support axes, which brake screw is connected to the shock absorber body via a bracket and rotated via a step motor
Data Source
Figure 1~2
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Figure 5~6
AI summary
This invention relates to an electromechanical friction shock absorber which is used in washing machines wherein the washing drum rotates on the horizontal axis. The electromechanical friction shock absorber (10, 11) comprises at least one cylindrical shock absorber piston (26); at least one shock absorber body (18) that surrounds the shock absorber piston (26), moving telescopically along the same work axis (X) with the piston (26), and bearing piston (26) from its end part; characterized by - at least one brake shoe (23) which is seated to the clearances (34, 3S) provided on the shock absorber body (18) via sliding surfaces (39, 40), and which surrounds the piston (26) and moves on the same work axis (X) with the body (18), - at least one friction element (30) which is located to me inner part of the brake shoe (23) and to the outer part of me shook absorber piston (26) fixed with retainer level (37) and whose surfaces along the work axis (X) do not contact the brake shoe (23); and - at least one lock ring (36) which bears the shock absorber piston (26) on the shock absorber body (18) and prevents the friction clement (30) from getting displaced out of the body (18), With the inventive electromechanical friction shock absorber, the dynamics of the washing machine drum is controlled in real and full time according to the amount of laundry, the resulting unbalanced load, spin speed of the drum, and as a result of ail these parameters, the amount of movement of the drum.