Ball Detent Latching Clutch Reduces Hydraulic Pressure
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Solution Overview
Problem
Dual clutch transmissions (DCTs) require high hydraulic pressure to maintain driving torque, which negatively impacts fuel economy during steady-state conditions due to the need for continuous high pressure to keep the clutch engaged.
Innovation Solution
A clutch arrangement incorporating a pre-compressed 'lost motion' spring and a ball detent latching device, where a low pilot pressure holds the clutch engaged by keeping the balls in a groove on the apply plate, reducing the need for high pressure to maintain driving continuity between driving and driven parts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high hydraulic pressure is applied to maintain clutch engagement, then the clutch can hold driving torque reliably, but fuel economy deteriorates due to continuous energy consumption
Solution Approach 1:
The patent replaces the traditional hydraulic pressure-based clutch holding mechanism with a mechanical ball detent latching system. The ball detent mechanism mechanically locks the clutch in the engaged position, eliminating the need for continuous high hydraulic pressure and thereby improving fuel economy while maintaining engagement reliability
Solution Approach 2:
The patent introduces a pilot pressure system as an intermediary mechanism. A small amount of hydraulic pressure (pilot pressure) is used to actuate the ball detent latching mechanism, which then mechanically holds the clutch engaged without requiring continuous high pressure, thus resolving the contradiction between reliable engagement and energy efficiency
2Stability of the object's composition
If high pressure is maintained continuously, then the clutch remains engaged during steady-state operation, but energy losses increase
Solution Approach 1:
The patent applies preliminary action by using pilot pressure to pre-compress the spring and actuate the ball detent latching mechanism before steady-state operation. Once latched, the mechanical holding mechanism maintains engagement stability without requiring continuous high pressure, thereby eliminating ongoing hydraulic energy losses
Solution Approach 2:
The ball detent latching mechanism provides self-service by mechanically maintaining clutch engagement once activated. The mechanical latch holds the clutch engaged through its own structural design without requiring continuous external energy input, thus achieving stable engagement with minimal energy consumption
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
This solution allows for reduced energy losses and improved fuel economy by minimizing the hydraulic pressure required to maintain clutch engagement during steady-state operation, while ensuring the clutch can engage and disengage efficiently.
Implementation Method 1
an apply spring operable to compress the apply plate axially to engage the clutch assembly
Implementation Method 2
a return spring operable to apply a force to the apply plate
Implementation Method 3
Fluid can be admitted into the enclosure to apply a force to the enclosure and the apply plate
Implementation Method 4
power-transmitting elements having mutually engageable surfaces for transmitting power from one to another substantially solely by friction forces
Data Source
AI summary
A power-transmitting device (10) and a method of assembling a power-transmitting device (10) secures and releases driving continuity between driving and driven parts (22, 62) through at least one clutch assembly (26, 66). The power-transmitting device (10) includes an apply plate (36) axially moveable with respect to the clutch assembly (26, 66) for engaging and disengaging the clutch assembly (26, 66). A return spring (34) acting on the apply plate (36) and an apply spring (32) having a higher compression force than the return spring (34) can be located between the apply plate (36) and the clutch assembly (26, 66). A ball (38) can be engageable with a portion of the apply plate (36) for locking the apply plate (36) in engagement with the clutch assembly (26, 66) during a steady state condition and a piston (40) can drive the ball (38) into engagement with the apply plate (36) in response to application of fluid under pressure.