Eccentric Locator Coils in Throttle Return Springs
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing electronic throttle control systems face issues with default throttle position variation due to excessive tolerance stack-up in single return spring designs, leading to undesirable limp home driving characteristics, and dual return spring designs increase part costs and assembly complexity.
Innovation Solution
A helical torsion return spring with specific winding radii and offset axes is used to position the throttle plate accurately, combined with a throttle body assembly featuring bushings to hold the spring in place, reducing positional variation and assembly complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single return spring design is used, then the assembly complexity is low, but the default throttle position variation is excessive due to tolerance stack-up
Solution Approach 1:
The return spring incorporates an eccentric locator coil section with a different winding radius than the main spring section. This localized structural variation creates a specific engagement point on the throttle shaft that serves as a precise mechanical reference, thereby reducing default throttle position variation without increasing overall assembly complexity
Solution Approach 2:
The patent replaces the need for multiple return springs with a mechanically engineered single spring featuring an eccentric locator coil. The eccentric geometry provides the necessary positioning precision that would otherwise require dual springs, substituting a complex mechanical arrangement with a refined single-component design
2Manufacturing precision
If dual return spring designs are used, then the default throttle position accuracy is improved, but the part costs and assembly complexity increase
Solution Approach 1:
The patent combines the functions of two separate return springs into a single integrated spring structure. The unified spring features both the main spring section for force generation and the eccentric locator coil section for positioning, merging multiple functions into one component and eliminating the need for dual springs
Solution Approach 2:
The single return spring performs multiple functions: the main spring section provides the restoring force while the eccentric locator coil section provides precise positioning on the throttle shaft. This multi-functional design eliminates the need for separate positioning mechanisms or dual springs, reducing both part count and assembly 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 solution provides improved default throttle positioning accuracy, minimizing peak torque and power requirements for the motor, while maintaining a predictable torque vs. deflection output and reducing assembly tolerances, thus enhancing limp home driving performance.
Implementation Method 1
a helical torsion return spring for urging a throttle plate of a throttle body assembly to a default position
Implementation Method 2
The middle portion is wound at a middle winding radius effective to define a middle portion center axis
Data Source
AI summary
A helical torsion return spring and a throttle body assembly for urging a throttle plate of a throttle body assembly to a default position when a throttle motor of the throttle body assembly is disabled. The return spring includes a middle portion, a first end portion, a second end portion, a first spring leg, and a second spring leg. The throttle body assembly includes a throttle shaft, a first bushing, a second bushing, and the spring defined above. A first end portion center axis defined by the first end portion and a second end portion center axis defined by the second end portion are offset from a middle portion center axis defined by the middle portion.