Planetary Gear Torsional Damper for Engine Vibration Isolation
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Solution Overview
Problem
Existing torsional dampers in motor vehicle propulsion systems are insufficient in isolating torsional vibrations due to design limitations and limited travel of the damper assembly, leading to inadequate vibration reduction between engines and transmissions.
Innovation Solution
Incorporating a planetary gear set with three nodes into the torsional vibration damper, where one node is connected to the engine output shaft, another to the transmission input shaft, and a third to the lockup clutch, allowing for improved isolation by using springs to deflect angularly between these nodes, thereby increasing the effective range of vibration reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional torsional damper with limited travel is used, then the structure is simple, but the torsional vibration isolation performance is insufficient
Solution Approach 1:
The patent merges the torsional damper with the torque converter by integrating the planetary gear set nodes directly into the torque converter components (turbine, lockup clutch, and transmission input shaft). This combination allows the damper to utilize the existing torque converter structure, improving vibration isolation performance without proportionally increasing overall system complexity.
Solution Approach 2:
The planetary gear set is nested within the torque converter assembly, with the sun gear, planet gears, and ring gear arranged in a compact configuration. The damper springs are positioned within the planetary gear structure, allowing the damping mechanism to be contained within the existing torque converter footprint while enhancing its vibration isolation capability.
2Reliability
If the damper assembly travel is limited, then the design space is constrained, but the angular displacement required for effective vibration reduction cannot be achieved
Solution Approach 1:
The patent transitions from linear damper travel to angular displacement by utilizing the rotational degrees of freedom of the planetary gear set nodes. The sun gear, planet gears, and ring gear can rotate and deflect angularly relative to each other, providing a new dimensional space for damper operation that is not constrained by linear travel limitations.
Solution Approach 2:
The patent changes the operational parameter from linear displacement to angular displacement. The damper springs are configured to deflect angularly as the planetary gear nodes rotate, allowing effective vibration reduction through rotational movement rather than linear compression or extension. This parameter change enables the damper to achieve greater effective travel within the same physical space.
3Reliability
If springs are used to dampen energy transfer, then vibration isolation is achieved, but the spring coefficient limitations restrict the isolation performance
Solution Approach 1:
The planetary gear set acts as an intermediary mechanism between the engine and transmission. The damper springs are positioned within the planetary gear structure, allowing them to deflect angularly as the gears rotate. This intermediary arrangement enables the springs to operate at optimal deflection angles, improving their ability to dampen energy transfer without being constrained by linear spring coefficient limitations.
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 planetary gear set configuration enhances torsional vibration isolation by increasing the maximum angular displacement and reducing spring coefficient limitations, resulting in more effective vibration reduction between the engine and transmission.
Implementation Method 1
Known torsional dampers use one or more springs to store energy and to dampen an energy transfer path between the engine and the transmission
Implementation Method 2
The planetary gear set configuration enhances torsional vibration isolation by increasing the maximum angular displacement and reducing spring coefficient limitations
Data Source
AI summary
A torque transfer assembly includes input and output members configured to transfer torque from a prime mover to an automotive transmission. A torque transfer component, such as a torque converter or a dual-mass fly wheel, and a clutch are coupled to the input member. A torsional vibration damper includes a planetary gear set having first, second, and third nodes. First and second spring engagement elements are connected to two of the first, second, and third nodes. One or more springs contacts both of the first and second spring engagement elements. An outgoing member of the torque multiplying device is coupled to the first node of the planetary gear set, a driven element of the clutch is connected to the second node of the planetary gear set, and the output member is coupled to the third node of the planetary gear set.