Coil Spring Asymmetric Geometry Bowing Prevention
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional coil springs produced by hot forming coiling machines often experience bowing under compressive loads, which can lead to interference with surrounding components, especially when the number of turns is five or less, and are difficult to produce with large wire diameters using cold forming coiling machines.
Innovation Solution
A coil spring design featuring a helical shape with a lower and upper end turn portion and an effective portion that maintains a cylindrical shape about a force line connecting the centers of force applied to these portions, ensuring a constant pitch and preventing bowing by adjusting the positions and inclinations of the turn portions relative to the spring seats.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional helical coil spring is used, then it provides suspension function, but bowing occurs under compressive load causing interference with surrounding components
Solution Approach 1:
The coil spring is designed with asymmetric geometry where the wire center positions are deliberately offset from the coil center in the radial direction. The distance from the wire center to the coil center varies around the circumference, creating an asymmetric cross-sectional shape that prevents bowing while maintaining suspension functionality.
2Object-affected harmful factors
If cold forming coiling machine is used to produce C-shaped or S-shaped coil spring to prevent bowing, then bowing is suppressed, but production becomes complex and difficult for large wire diameters
Solution Approach 1:
The invention changes the geometric parameters of the coil spring by introducing asymmetric wire center positions and varying radial distances. This parameter modification allows the spring to prevent bowing through its geometry alone, enabling production by conventional hot forming coiling machines without requiring complex C-shaped or S-shaped configurations.
3Ease of manufacture
If hot forming coiling machine is used to produce coil spring with large wire diameter, then production is simplified, but bowing occurs particularly when number of turns is five or less
Solution Approach 1:
The asymmetric design with offset wire centers and varying radial distances is particularly effective for coil springs with fewer turns. This geometric asymmetry provides inherent stability against bowing, allowing hot forming coiling machines to produce large wire diameter springs with five or fewer turns without the bowing problems that plague conventional symmetric designs.
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 coil spring design effectively suppresses bowing, preventing interference with surrounding components and allowing for production using a hot forming coiling machine, even with large wire diameters, ensuring reliable operation in vehicle suspensions.
Implementation Method 1
a method of forming the coil spring by hot working... the coil spring is formed into a helical shape by winding a wire that is heated to a high temperature
Implementation Method 2
the coil spring is formed into a helical shape by winding a wire that is heated to a high temperature... around a mandrel
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
A coil spring (2) according to one embodiment includes a lower end turn portion (20) which is in contact with a lower spring seat (10), an upper end turn portion (21) which is in contact with an upper spring seat (11), and an effective portion (22) between the lower end turn portion (20) and the upper end turn portion (21). The coil spring (2) is cylindrical about an axis of the effective portion (22) in its free shape which is not compressed. Further, with respect to a coordinate system in which a force line (FL) is assumed as a Z-axis, the coil spring (2) is cylindrical with a constant pitch in a direction along the Z-axis in its compressed shape which is compressed to a specified height.