Telescoping Tube Counterbalance with Nested Springs
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Solution Overview
Problem
Current counterbalance mechanisms for vehicle closure panels, such as lift gates, are complex, expensive, and inefficient, requiring additional support systems and manual effort due to non-linear load curves and space constraints, leading to suboptimal performance and increased packaging size.
Innovation Solution
A telescoping tube counterbalance mechanism with two springs in series, where one spring is positioned inside the outer tube and the other inside the inner tube, with a seal between them, allowing for optimal matching of the lift gate's load curve and minimizing manual effort and actuator load, while maintaining a compact design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a seal is positioned between the inner tube and outer tube in telescoping tube arrangements, then sealing effectiveness is improved, but the space available for spring coils is reduced by approximately 40-50%
Solution Approach 1:
The patent positions the seal between the inner tube and outer tube, and places the spring coils in the annular space formed by this nested arrangement. The stopper is positioned to allow the seal to be located between the springs while maintaining adequate coil space, effectively nesting the sealing system within the telescoping tube structure without sacrificing spring volume.
2Power
If multiple springs are used in parallel configuration with a kicker spring, then motor load requirements are reduced, but the spring K constant cannot be made flatter in the Stop-and-Hold zone
Solution Approach 1:
The patent divides the spring system into multiple springs (first spring, second spring, third spring) that can be positioned at different locations along the telescoping tube assembly. This segmentation allows each spring to contribute differently to the overall force profile, enabling optimization of both motor load reduction and Stop-and-Hold zone characteristics through strategic placement rather than parallel configuration.
3Ease of operation
If the lift gate load curve and counterbalance load curve are closely matched, then friction requirements are reduced, but the packaging size increases due to additional components
Solution Approach 1:
The patent combines the counterbalance function, sealing system, and spring mechanism into a single integrated telescoping tube assembly. The first, second, and third springs work together within the nested tube structure to provide load curve matching, while the seal positioned between the tubes provides sealing without requiring separate sealing components. This merging reduces packaging size compared to separate systems while maintaining reduced manual effort through optimized load curve matching.
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
This configuration enhances the matching of the lift gate's load curve, improving the Stop-and-Hold functionality, reducing manual effort, and minimizing actuator drive-train loads, while maintaining a compact and efficient packaging size.
Implementation Method 1
a first spring positioned along the extension axis in an interior of the outer tube; a second spring positioned along the extension axis in an interior of the inner tube
Data Source
AI summary
An extension mechanism for coupling with a closure panel to assist in opening and closing of the closure panel of a vehicle between a fully closed position and a fully open position of the closure panel, the extension mechanism including: an inner tube having an outer surface; an outer tube having an inner surface and overlapping the inner tube for at least a portion of the outer surface along an extension axis, such that the inner surface and the outer surface are adjacent to one another when overlapped; a first spring positioned along the extension axis in an interior of the outer tube; a second spring positioned along the extension axis in an interior of the inner tube; a seal positioned between the inner surface and the outer surface; and a stopper to engage the first spring at one end and engage the second spring at an opposite end such that the first spring and the second spring are in series with one another along the extension axis; wherein the one end and the opposite end are spaced apart from one another such that the seal is positioned between the one and opposite end.