Planetary Torque Converter Damper for Torsional Vibration Control
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Solution Overview
Problem
Current powertrain systems with hydrodynamic torque converters experience significant torsional vibrations and noise due to the inherent slip between the impeller and turbine, leading to efficiency losses and increased vehicle noise, vibration, and harshness (NVH), which affect fuel economy and overall vehicle performance.
Innovation Solution
Integration of a planetary-type torsional vibration damper within the torque converter assembly, comprising a sun gear, ring gear, and planet carrier, which are securely attached to the turbine and clutch components, effectively isolating and mitigating torsional vibrations by intermeshing pinion gears and using compression springs to minimize damping element travel and reduce assembly size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a torque converter is used to allow the crankshaft to spin without engine stalling, then the ability to transmit torque is improved, but torsional vibrations and noise increase
Solution Approach 1:
A planetary-type torsional vibration damper is introduced as an intermediary component between the impeller and turbine. The damper includes a sun gear, ring gear, planet carrier with pinion gears, and compression springs that absorb and attenuate torsional vibrations while allowing torque to pass through the fluid coupling system.
Solution Approach 2:
The compression springs in the planetary damper change their stiffness characteristics dynamically to absorb torsional vibrations. The springs compress and expand in response to vibration frequencies, transforming harmful vibrational energy into elastic deformation and heat, thereby reducing noise and vibration transmission.
2Object-generated harmful factors
If compression springs are used to mate the planet carrier with the ring gear, then torsional vibrations are dampened, but the travel distance of damping elements increases
Solution Approach 1:
The planetary gear set is nested within the torque converter housing, with the sun gear, ring gear, and planet carrier arranged in a compact concentric configuration. The compression springs are positioned within the planetary mechanism, allowing the entire damping system to occupy minimal space while effectively reducing torsional vibrations through the intermeshing gears and spring elements.
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 integrated torsional vibration damper significantly reduces torque swings and vibrational excitation, minimizing NVH, enhancing vehicle quietness and efficiency, and allowing for reduced packaging space and part costs, while being applicable to both standard and electric-drive vehicle architectures.
Implementation Method 1
Circumferentially spaced compression springs, which are carried by a spring retainer disc, mate the planet carrier with the ring gear
Implementation Method 2
The damper includes a planetary gear set with an outer ring gear that is concentrically aligned with a central sun gear. Mounted onto a planet carrier are circumferentially spaced pinion-type 'planet' gears that are intermeshed with the ring gear and sun gear.
Data Source
AI summary
Presented are torque converters (TC) with planetary-type vibration dampers, methods for making/using such TC assemblies, and vehicles equipped with such TC assemblies. A TC assembly includes a TC housing drivingly connected to a prime mover to receive torque therefrom, and a TC output member drivingly connected to a transmission to transfer torque thereto. Rotatably mounted within an internal fluid chamber of the TC housing are juxtaposed turbine and impeller blades. The impeller blades are rotatably mounted to the housing. A TC clutch is operable to lock the TC housing to the TC output member. A torsional vibration damper, which is disposed within the internal fluid chamber, includes a sun gear attached to the TC output member for unitary rotation, a ring gear attached to the TC clutch for unitary rotation, and a planet carrier intermeshed with the ring and sun gears and attached to the turbine blades for unitary rotation.