Nested Spring Assembly for Constant-Force Seal Energizing
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Solution Overview
Problem
Helical ribbon springs have limitations in force versus deflection characteristics, which can lead to limited sealing performance and potential deformation during high deflection, whereas canted coil springs provide a more constant force but with limited contact surface area, making them less ideal for uniform sealing.
Innovation Solution
A spring assembly comprising an inner canted coil spring or helical ribbon spring positioned inside an outer helical ribbon spring, where the inner spring modifies the force versus deflection curve of the outer spring, providing additional support and a larger contact surface area for improved sealing performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a canted coil spring is used as an energizer for a seal element, then a relatively constant force is maintained over a range of deflection, but the contact surface area is limited to the wire diameter
Solution Approach 1:
The patent combines a canted coil spring and a helical ribbon spring into a single spring assembly. The canted coil spring provides constant force over deflection range, while the helical ribbon spring provides larger contact surface area. Both springs work together to energize the seal element, merging their complementary advantages to resolve the contradiction between force constancy and contact surface area.
Solution Approach 2:
The spring assembly uses two different spring types (canted coil and helical ribbon) with distinct mechanical properties. The canted coil spring offers constant force characteristics, while the helical ribbon spring offers broad contact surface. This composite spring structure integrates different material behaviors to simultaneously achieve force constancy and adequate contact area.
2Area of stationary object
If a helical ribbon spring is used, then a greater contact surface area is provided against the seal element, but the force versus deflection curve is steep and linear with limited maximum deflection
Solution Approach 1:
The patent merges a helical ribbon spring with a canted coil spring in a single assembly. The helical ribbon spring contributes its advantage of large contact surface area, while the canted coil spring contributes its advantage of constant force over deflection. This combination allows the seal energizer to simultaneously achieve both broad contact and favorable force-deflection characteristics.
3Device complexity
If a single spring is used, then the device complexity is low, but the sealing performance and uniformity are limited
Solution Approach 1:
The patent combines two spring types into a unified spring assembly that functions as a single integrated component. This merger provides enhanced sealing performance through complementary mechanical properties while maintaining relatively simple installation and operation procedures, achieving a balance between complexity and reliability.
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 combination of springs enhances the sealing performance by maintaining a constant force over a range of deflection and providing a larger contact surface area, minimizing the risk of deformation and ensuring uniform sealing pressure.
Implementation Method 1
A canted coil spring (CCS) exhibits a unique characteristic of a relatively flat force versus deflection relationship that can be used with, for example, a seal element to maintain a relatively constant load on the seal lips over a range of deflection to compensate for tolerance issues thereby can extend seal life
Implementation Method 2
Relative to a canted coil spring, a helical ribbon spring has a steep and linear force versus deflection curve, and a much lower maximum deflection amount before permanent deformation
Data Source
Figure 1A~2B
Figure 3A~4B
Figure 5A1~5B2
AI summary
A spring assembly with two or more springs, one inside another. The spring assembly can have two springs wherein one spring is located inside another spring, and the outer spring can be a helical ribbon spring and the inner spring can be a canted coil spring to provide support to the outer helical ribbon spring. Support is provided where the helical ribbon spring may have some limitations that the inner spring is able to overcome. Limitations of the helical ribbon spring may be a limited force versus deflection curve which the additional spring support of the secondary spring may overcome.