Opposite Load Clutch Actuation for Heat Distribution
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Solution Overview
Problem
Clutch assemblies in vehicle transmissions often experience overheating at friction interfaces near the clutch actuator, leading to reduced torque capacity and compromised drive quality, as existing solutions to mitigate overheating, such as using oversized friction plates or reducing engine output, result in efficiency, packaging, and cost drawbacks.
Innovation Solution
A clutch assembly design with a clutch pack that includes a first and second apply plate, where both ends are actuated in opposing directions to compress and decompress the friction and reaction plates, distributing torque and heat more evenly across the pack, thereby reducing localized temperature spikes without increasing size or cooling capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If unidirectional pressure is applied to the clutch pack by a single actuator, then the clutch assembly structure is simple, but localized overheating occurs at friction interfaces near the actuator
Solution Approach 1:
The clutch pack is segmented into two separate actuation zones with a first actuator applying pressure to a first apply plate and a second actuator applying pressure to a second apply plate. This segmentation distributes the torque transmission and heat generation across multiple locations rather than concentrating them at a single actuator location, thereby reducing localized overheating while maintaining structural simplicity.
Solution Approach 2:
Different regions of the clutch pack are given different functional qualities by providing separate actuators at opposite ends. The first actuator and second actuator create localized pressure zones that can be independently controlled, allowing heat distribution to be optimized without requiring a completely restructured actuator system.
2Temperature
If oversized friction plates are used to reduce overheating, then heat dissipation is improved, but the clutch assembly size and cost increase
Solution Approach 1:
Instead of increasing the size of individual friction plates, the system segments the torque transmission function across multiple friction plate sets (first friction plates and second friction plates) actuated by separate actuators. This allows heat to be distributed across multiple smaller interfaces rather than requiring each interface to handle the full thermal load, avoiding the need for oversized plates.
3Temperature
If torque transmission is reduced to prevent overheating, then friction interface temperature decreases, but driving quality and power delivery are compromised
Solution Approach 1:
The torque transmission function is segmented across multiple friction interfaces actuated by separate actuators. This allows the total torque capacity to be maintained by distributing it across multiple smaller torque paths, each operating at lower thermal stress levels. The first and second actuators can work simultaneously or sequentially to maintain overall productivity while preventing localized overheating.
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 reduces the likelihood of overheating while maintaining clutch assembly efficiency and drive quality by evenly distributing torque and heat across the clutch pack, eliminating the need for early clutch engagement or reduced engine output.
Implementation Method 1
Torque transfer between the friction plates and the reaction plates then occurs through friction interfaces that are disposed between adjacent friction plates and reaction plates
Implementation Method 2
The kinetic energy of the relative motion between the friction plates and the reactions plates is absorbed during slippage and converted to friction generated heat
Data Source
AI summary
A clutch assembly that is less prone to overheating is disclosed. The clutch assembly includes a clutch housing, a shaft, and a clutch pack. The clutch pack includes a first apply plate, a second apply plate, a plurality of friction plates, and a plurality of reaction plates. The clutch assembly further includes a first actuator and a second actuator. The first actuator applies pressure to the first apply plate in a first direction to move the first apply plate toward the second apply plate. The second actuator applies pressure to the second apply plate in a second direction to move the second apply plate toward the first apply plate. The first direction is opposite the second direction such that the first and second actuators apply pressure to the clutch pack in opposing directions. This reduces localized temperature spikes in the clutch pack.