Nested Spring-Mass Damper for Hybrid Powertrain Torsional Vibration
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Solution Overview
Problem
Conventional vehicle powertrain systems face challenges in minimizing driveline vibrations and torque fluctuations caused by internal combustion engines, particularly in hybrid vehicles where engine startup and shutdown operations are frequent, leading to undesirable vibrations and noise.
Innovation Solution
A spring-mass damper system assembly with inner and outer springs and specific retainer geometries is implemented to provide a step-rate dampening effect, attaching to a torsional damper assembly on the powertrain, which absorbs and attenuates torsionals and vibrations by compressing the springs in a progressive two-phase process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional single-spring damper systems are used, then the structure is simple, but the dampening effectiveness is insufficient for hybrid vehicle operations
Solution Approach 1:
The damper system is segmented into multiple spring elements (first spring, second spring, third spring) with different stiffness characteristics, allowing each spring to handle specific portions of the vibration spectrum and torque fluctuation ranges
Solution Approach 2:
The springs are arranged in a nested configuration where the first spring, second spring, and third spring are positioned concentrically relative to each other, with the second spring inside the first spring and the third spring inside the second spring, creating a compact multi-stage dampening system
2Object-affected harmful factors
If the damper system uses multiple springs with different stiffness, then the vibration absorption is improved, but the manufacturing complexity increases
Solution Approach 1:
The nested spring arrangement allows all springs to be installed through a single central opening, and the retainers simultaneously secure multiple springs in their respective positions, simplifying the assembly process despite the multiple spring components
Solution Approach 2:
The first retainer and second retainer serve multiple functions: they secure the springs to the damper assembly, maintain the nested configuration, and provide mounting surfaces for the springs, reducing the need for additional separate components
3Strength
If the springs are arranged in parallel, then the torque capacity is increased, but the space requirement increases
Solution Approach 1:
The springs are arranged concentrically with the first spring having the largest outer diameter, the second spring nested inside with a smaller outer diameter, and the third spring nested inside the second with the smallest outer diameter, achieving parallel spring functionality in a compact radial footprint
Solution Approach 2:
Instead of arranging springs side-by-side in the radial direction, the springs are stacked in the axial direction through nesting, transforming the spatial arrangement from a two-dimensional radial layout to a three-dimensional concentric configuration that preserves torque capacity while minimizing radial space
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 effectively reduces driveline vibrations and improves torque converter balancing, enhancing the smooth operation and reducing noise in vehicle powertrains by selectively engaging and compressing the springs to absorb engine-generated torsionals and compression pulses during various engine modes.
Implementation Method 1
absorbing and attenuating torsionals and vibrations transmitted to a power transmission
Implementation Method 2
compressing the springs in a progressive two-phase process
Data Source
AI summary
A damper assembly for absorbing and attenuating torsionals and vibrations transmitted from an engine to a transmission is provided. The damper assembly includes a damper flange with a plurality of spring-mass damper systems operatively attached thereto and elongated circumferentially about its outer periphery. Each spring-mass damper systems include an inner spring nestably positioned inside an outer spring, a first spring retainer having a base portion defining a first interface surface with a first pilot portion extending therefrom to define a second interface surface with a second pilot portion extending therefrom, and a second spring retainer having a base portion defining an interface surface with a pilot portion extending therefrom to define a fourth interface surface. The first and third pilot portions engage with and thereby restrict axial and radial movement of the outer spring. The second pilot portion is attached to the inner spring thereby restricting relative movement therebetween.