Input Damper Torque-Limiting Clutch Angular Displacement Mechanism

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Solution Overview

Problem

Conventional input dampers are limited in capacity and can cause damage to input shafts and transmissions due to extreme torque spikes, as they become a solid coupling when springs reach their travel limit, failing to effectively manage torque spikes beyond their capacity.

Innovation Solution

An input damper design incorporating a torque-limiting clutch with an angular displacement mechanism that moves between engaged and disengaged positions, using a clutch assembly with friction material and springs, and a wedging mechanism to prevent excessive torque transfer by mechanically decoupling the clutch when torque exceeds the damper's capacity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a conventional input damper uses springs to dampen torque spikes, then torque spikes are reduced during normal operation, but the damper becomes a solid coupling when springs reach their travel limit, allowing undampened torque spikes to affect the input shaft and transmission

Engineering Contradiction:
Improveprotection against torque spikesVSAvoidcapacity range
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The clutch assembly is designed to dynamically change its engagement state based on torque magnitude. During normal operation, the clutch is disengaged allowing spring dampening. When torque exceeds clutch capacity, the clutch slips to prevent solid coupling transmission of extreme spikes, providing adaptive protection across varying torque conditions

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes the operational parameter of torque transmission by introducing a clutch with specific friction characteristics. The clutch slip condition changes the effective damping parameter from spring-only to friction-based slip, allowing the system to adapt its torque handling characteristics based on the magnitude of applied torque

Inventive Principle:
Principle #35Parameter changes

2Reliability

If a torque-limiting clutch is designed at or near the maximum capacity of the input damper, then the clutch may slip before full capacity or reach full capacity at which point extreme torque spikes are fully transferred to the input shaft

Engineering Contradiction:
Improvetorque spike limitationVSAvoidclutch capacity design
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The angular displacement mechanism acts as an intermediary between the clutch assembly and the damper springs. It provides a mechanical linkage that translates clutch slip into angular displacement, ensuring the clutch disengages at the precise moment when spring travel is exhausted, preventing both premature and delayed slip

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The angular displacement mechanism provides mechanical feedback from the spring compression state to the clutch assembly. As springs compress and reach their travel limit, the angular displacement mechanism triggers clutch disengagement, creating a feedback loop that ensures clutch capacity is precisely matched to damper capacity without requiring complex adjustment mechanisms

Inventive Principle:
Principle #23Feedback

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 prevents damage to input shafts and transmissions by allowing the torque-limiting clutch to mechanically slip and dissipate torsional energy, maintaining a high clutch capacity that releases at the end of the damper stroke, thereby protecting the system from excessive torque.

Implementation Method 1

a spring biasedly disposed against the backing plate

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

friction material disposed on at least one of the backing plate and flange portion

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP3578852A1Limiting torque clutch in an input damper
Publication Date: 2019.12.11 ALLISON TRANSMISSION INC
  • EP3578852A1 patent drawingFigure 1
  • EP3578852A1 patent drawingFigure 2
  • EP3578852A1 patent drawingFigure 3~4

AI summary

An input damper (102) for coupling to a torque-generating mechanism, comprising an outer cover (106), a hub (110) having a plurality of splines (114) configured to couple to an input shaft (116), and a carrier assembly coupled to the hub, where the carrier assembly is movably disposed within the outer cover. The input damper further comprises a clutch assembly having an engaged position and a disengaged position, the clutch assembly being biased towards the engaged position, an angular displacement mechanism operably coupled to the clutch assembly for moving the clutch assembly between the engaged position and disengaged position, and a damper spring (206) disposed in the outer cover and having a compressed position and an uncompressed position, where the damper spring is rotationally coupling the outer cover to the clutch assembly. When the clutch assembly is in the engaged position, the damper spring is in the uncompressed position and the outer cover is coupled to the carrier assembly. The angular displacement mechanism comprises a first portion and a second portion, the first portion being disposed on the cover and the second portion being disposed on the carrier assembly. The first portion is an angled surface of the cover and the second portion is a ramp (1126) defined in the carrier assembly, where contact between the angled surface and ramp induces a movement of the clutch assembly from the engaged position to the disengaged position.