Disk Spring Preload Mechanism for Quasi-Zero-Stiffness Isolation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing vibration isolators in vehicle seats, such as linear spring and quasi-zero-stiffness (QZS) isolators, fail to effectively reduce vibration transmission across a wide range of weights, as they either do not compress into their quasi-zero-stiffness region or are compressed beyond it, leading to inadequate vibration isolation.
Innovation Solution
A vibration isolator pre-load mechanism that applies an axial pre-load force to a stack of disk spring washers, ensuring they operate within the quasi-zero-stiffness range by using a compression fixture to adjust the force based on the weight applied, thereby maintaining effective vibration isolation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If QZS vibration isolators are used to reduce vibration transmission, then vibration isolation performance is improved, but the isolator only works effectively within a limited range of forces and deflections
Solution Approach 1:
The patent employs a stack of disk springs with varying stiffness characteristics that dynamically adjust the isolator's response based on applied load. The combination of multiple disk springs creates a force-deflection curve that maintains QZS behavior across a broader range of forces, allowing the system to adapt to different weight conditions while preserving vibration isolation performance
Solution Approach 2:
The vibration isolator uses a composite structure combining multiple disk springs with different stiffness properties. This composite spring stack creates a combined force-deflection characteristic that extends the QZS region beyond what a single spring design could achieve, enabling effective vibration isolation across varying load conditions
2Object-affected harmful factors
If the spring stack is designed to produce quasi-zero-stiffness response, then vibration transmission is reduced, but the isolator may not reach the QZS region when weight is placed on the seat
Solution Approach 1:
The patent incorporates a pre-load mechanism that applies an initial compressive force to the disk spring stack during assembly or installation. This preliminary action ensures that when a passenger sits on the seat, the spring stack is already positioned within or near the QZS region of its force-deflection curve, guaranteeing reliable vibration isolation performance from the moment the load is applied
3Device complexity
If linear spring vibration isolators are used, then simple design is maintained, but vibrations are still felt in the seat base and transferred to the seat back
Solution Approach 1:
The patent replaces simple linear springs with a composite structure of multiple disk springs stacked together. This composite arrangement creates a non-linear force-deflection relationship with a QZS region, dramatically improving vibration isolation performance while maintaining a relatively simple overall design that fits within existing seat mounting configurations
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 mechanism ensures that the spring stack remains in the quasi-zero-stiffness range, significantly reducing vibration transmission between the vehicle floor and seat, providing a smoother ride by absorbing vibrations without significant resistance, thus improving comfort across varying weights.
Implementation Method 1
the spring stack compresses or uncompresses very easily in response to small changes in applied force, as though it had a stiffness or spring constant close to zero... when subjected to a force in this design range of forces, the spring stack may be deflected over a relatively wide range of values in response to little or no increase in the applied force
Data Source
AI summary
An apparatus includes a vibration isolator which incorporates at least two disk spring washers. Each disk spring washer has at least one ring-shaped outer spacer coupled to the outer edges of one or two of the disk spring washers, and at least one ring-shaped inner spacer coupled to the inner edges of one or two of the disk spring washers. A bottom attachment portion supports the disk spring washers, and a top attachment portion, with an application of a downward preload force, compresses the disk spring washers. A compression fixture applies and holds the preload force to the top attachment portion, and a second top attachment portion, with application of an additional downward force, further compresses the at least two disk spring washers.