Centrifugal Pendulum Absorber Spring Retention Design
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Solution Overview
Problem
Conventional centrifugal pendulum absorber designs that use an interference fit for clamping springs between masses are sensitive to variations in spring length and the number of dead coils, leading to inefficiencies and performance issues.
Innovation Solution
A centrifugal pendulum absorber design that connects masses using a spring with enlarged end portions extending past the outer diameter of the coils, secured without an interference fit, allowing for reliable retention and reduced dead coils, thereby enhancing performance and space efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an interference fit is used to clamp the spring between the masses, then the spring is retained securely, but the design becomes sensitive to variance in spring length and the number of dead coils
Solution Approach 1:
The patent introduces an enlarged end portion of the spring as an intermediary element that mediates between the spring and the mass. This enlarged end portion fits into a corresponding recess in the mass, providing a positive mechanical engagement that eliminates the sensitivity to spring length variations inherent in interference fit designs. The intermediary structure allows for tolerance accommodation while maintaining secure retention.
Solution Approach 2:
The patent changes the geometric parameters of the spring by adding enlarged end portions that extend beyond the outer diameter of the spring coils. This parameter change transforms the retention mechanism from relying on interference fit (sensitive to length) to relying on positive mechanical engagement through the enlarged ends (insensitive to length variations).
2Reliability
If conventional interference fit design is used, then spring retention is achieved, but dead coils are required which reduce space efficiency
Solution Approach 1:
The enlarged end portion acts as an intermediary that provides retention functionality without requiring dead coils. By creating a mechanical interlock through the enlarged end fitting into the recess, the design eliminates the need for additional dead coils that would otherwise be required for retention, thereby improving space efficiency.
3Manufacturing precision
If enlarged end portions are used to connect springs to masses, then interference fit is eliminated and manufacturing tolerance is improved, but the spring structure becomes more complex
Solution Approach 1:
The patent modifies the spring structure by changing its geometric parameters - specifically adding enlarged end portions. While this does increase structural complexity, the benefit of eliminating sensitivity to spring length variations and dead coil requirements provides a net improvement in manufacturability and performance.
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 design effectively retains springs with a wide range of lengths and diameters, reducing the need for dead coils and improving the overall performance of the torque converter by eliminating interference fit-related issues.
Implementation Method 1
a spring extending circumferentially from first notches in the masses of the first pair into second notches in the masses of the second pair
Implementation Method 2
centrifugal pendulum absorber including springs fixed to circumferential edges of masses
Data Source
AI summary
A centrifugal pendulum absorber is provided. The centrifugal pendulum absorber includes a first pair of masses, a second pair of masses, and a spring extending circumferentially from first notches in the masses of the first pair into second notches in the masses of the second pair. The spring connects the first pair of masses and the second pair of masses and includes a first enlarged end portion extending past an outer diameter of coils of the spring and a second enlarged end portion extending past the outer diameter of the coils of the spring. The first enlarged end portion is connected to the first pair of masses in the first notches without an interference fit and the second enlarged end portion being connected to the second pair of masses in the second notches without an interference fit. A method of forming a centrifugal pendulum absorber is also provided.