Tapered Shaft Torsional Spring Axial Constraint
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current rotational rubber springs fail to control axial forces in addition to torsional forces, as they have a uniform cross-sectional shape that allows for freedom of motion in the axial direction, lacking the necessary constraint.
Innovation Solution
A torsional spring and axial control device featuring a shaft with a trapezoidal cross-sectional shape and conically shaped elastomeric members, where the cross-sectional shape gradually transitions in size, providing both rotational damping and axial constraint by restricting motion in specific directions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a uniform cross-sectional shape is used for the shaft and elastomeric members, then the device can be easily manufactured using extrusion processes, but the device fails to control axial forces and allows freedom of motion in the axial direction
Solution Approach 1:
The shaft and elastomeric members transition from uniform cross-section to tapered cross-section, creating local variation in geometry. The tapered shape provides different functional properties at different locations: the larger cross-section at one end provides axial constraint while the smaller cross-section at the other end allows for assembly and maintains torsional flexibility.
Solution Approach 2:
The cross-sectional area parameter is changed along the length of the shaft and elastomeric members, creating a gradient from uniform to tapered geometry. This parameter change enables the device to provide axial constraint through the varying cross-section while maintaining ease of manufacture through conventional extrusion processes followed by cutting and assembly.
2Device complexity
If the elastomeric members have a uniform cross section, then the structural design is simple, but the device cannot provide both rotational damping and axial constraint simultaneously
Solution Approach 1:
The tapered elastomeric members serve multiple functions simultaneously: they provide rotational damping through torsional deformation, axial constraint through the geometric interference of the tapered shape, and force transmission between the shaft and casing. This multi-functionality is achieved within a relatively simple structural framework.
Solution Approach 2:
The elastomeric members feature an asymmetric tapered cross-section rather than a symmetric uniform cross-section. This asymmetry in geometry enables the members to engage differently with the shaft and casing under various loading conditions, providing both rotational and axial control functions that a symmetric uniform cross-section cannot achieve.
3Reliability
If a tapered cross-sectional shape is implemented, then axial constraint is provided through geometric interference, but the manufacturing process becomes more complex
Solution Approach 1:
The tapered shape is pre-formed during the extrusion or molding process, and the components are cut to specific lengths before assembly. This preliminary formation of the tapered geometry eliminates the need for complex post-processing operations, maintaining ease of manufacture while achieving the axial constraint function.
Solution Approach 2:
The cross-sectional area parameter is varied along the length of the components in a controlled manner during manufacturing. By implementing this parameter change during the primary forming process rather than through secondary operations, the device achieves axial constraint functionality without significantly increasing manufacturing complexity.
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 device effectively dampens rotational motion while providing axial constraint, reducing stress under torsional and axial loading, and allowing for optimization of dampening and spring rates through the varying cross-sectional shape.
Implementation Method 1
Rotational rubber springs or dampeners offer resistance in a torsional direction... The rotational difference compresses each of the elastomeric elongated members. The compression generates a resistance to the applied torsional force. The resistance is provided in a form of a spring and a damper.
Implementation Method 2
Rotational rubber springs or dampeners offer resistance in a torsional direction... The rotational difference compresses each of the elastomeric elongated members. The compression generates a resistance to the applied torsional force. The resistance is provided in a form of a spring and a damper.
Data Source
AI summary
A rotational and axial control spring includes a tubular casing, a shaft, and a plurality of elongated elastomeric members. The casing comprises a tubular cross sectional equilateral convex polygon shape, the tubular shape extending uniformly between a first and second casing end. The shaft is fabricated having a cross sectional shape mimicking the equilateral convex polygon casing shape, a series of exterior surfaces extending longitudinally between a first smaller end and second larger end, wherein the exterior surfaces form a square frustum shape. The elastomeric members are formed as cylindrical frustums. The shaft is inserted within the casing interior. Each elastomeric member is positioned contacting a respective shaft exterior surface and a pair of adjacent casing interior surfaces. The elastomeric members provide rotational spring with adjustable resistant force and dampening functions. The tapered features provide an axial retention function.