Three Parameter Isolator Linear Guide System
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Solution Overview
Problem
Three parameter isolators, used in spacecraft for vibration isolation, experience significant lateral bending modes due to lateral disturbance forces, leading to off-axis motion and mechanical stress, which is problematic especially at frequencies critical to mission requirements, and current solutions result in heavier, bulkier designs unfavorable for aerospace applications.
Innovation Solution
A three parameter isolator with a main spring linear guide system that restricts off-axis movement, incorporating a secondary spring and damper assembly, and a non-sealing sliding interface to prevent lateral displacement and rotation, allowing for a compact and lightweight design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the isolator components are produced to have a greater structural robustness to resist lateral bending modes, then the resistivity to off-axis motion is improved, but the isolator becomes heavier and bulkier
Solution Approach 1:
The isolator is divided into distinct functional components: a main spring for primary vibration isolation, and a separate linear guide system for lateral constraint. This segmentation allows each component to be optimized independently - the main spring for weight reduction and the linear guide for lateral stability - resolving the contradiction between weight and resistivity to off-axis motion.
Solution Approach 2:
The linear guide system acts as an intermediary component between the main spring and the mounting structure. It mediates the lateral disturbance forces by providing a dedicated constraint mechanism, preventing these forces from directly loading the main spring and allowing the main spring to remain lightweight while still achieving high resistivity to off-axis motion through the combined system.
2Reliability
If a linear guide system is added to restrict off-axis movement, then the lateral bending modes are reduced, but the device complexity increases
Solution Approach 1:
The linear guide system performs multiple functions simultaneously: it constrains lateral displacement, prevents rotational movement, and guides the main spring's axial motion. This multi-functionality reduces the need for additional separate components, thereby limiting the increase in device complexity while achieving comprehensive lateral bending mode reduction.
Solution Approach 2:
The linear guide system is designed to nest around the main spring in a coaxial arrangement. This nested configuration allows the guide to provide lateral constraint without requiring significant additional space or complex external structures, minimizing the increase in device complexity while effectively reducing lateral bending modes.
3Volume of moving object
If the linear guide system is made compact, then the isolator envelope is minimized, but the manufacturing precision requirements increase
Solution Approach 1:
The linear guide utilizes thin-walled cylindrical structures that provide lateral constraint with minimal material and small envelope. These thin-walled structures achieve the required lateral stiffness for compact dimensions while maintaining manufacturability, balancing the trade-off between compact size and manufacturing precision requirements.
Solution Approach 2:
The guide system's geometric parameters (such as wall thickness, diameter, and length) are optimized to achieve the minimum necessary envelope while maintaining adequate manufacturing tolerances. By carefully selecting and adjusting these parameters, the design achieves compact dimensions without excessively tightening manufacturing precision requirements.
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 isolator effectively reduces lateral bending modes and shifts them to higher frequencies, maintaining robustness while minimizing the isolator's envelope and weight, thus addressing the challenge of mechanical stress and bulkiness in aerospace applications.
Implementation Method 1
A non-sealing sliding interface is formed between the first and second guide members. The non-sealing sliding interface permitting relative movement of the first and second guide members along the working axis, while preventing relative movement of the first and second guide members along a lateral axis perpendicular to the working axis.
Data Source
Figure 1~2
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AI summary
Embodiments of isolators (16), such as three parameter isolators, including a main spring linear guide system are provided. In one embodiment, the isolator includes first and second opposing end portions (44, 46), a main spring (76) mechanically coupled between the first and second end portions, and a linear guide system (110) extending from the first end portion, across the main spring, and toward the second end portion. The linear guide system expands and contracts in conjunction with deflection of the main spring along a working axis (48), while restricting displacement and rotation of the main spring along first and second axes orthogonal to the working axis.