Nested Clutch Module With Hollow Shaft Fluid Passageways
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Solution Overview
Problem
Conventional automatic transmissions face challenges in efficiently managing power transmission across a wide range of vehicle speeds due to engines that operate effectively only within a narrow speed range, requiring transmissions capable of varying speed ratios to optimize acceleration and fuel efficiency.
Innovation Solution
A multiple clutch module with first, second, and third clutch packs, each with a pressure plate and separator plates, is used, where pistons apply axial force to transmit torque, and a hollow shaft with passageways conducts pressurized fluid to apply chambers for clutch engagement, with unpressurized fluid balancing chambers to prevent unintended clutch activation from centrifugal forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a multiple clutch module with stacked clutch packs is used, then the transmission can efficiently manage power transmission across various speed ratios, but the device complexity increases due to multiple pistons and fluid passageways
Solution Approach 1:
The patent implements nested clutch packs where the first, second, and third clutch packs are stacked axially with the second clutch pack positioned between the first and third clutch packs. The first piston extends through openings in the second clutch pack components to reach the first clutch pack, creating a nested arrangement where components of one clutch pack are positioned within the axial space of adjacent clutch packs. This nesting allows multiple clutches to be integrated in a compact configuration, managing power transmission across multiple speed ratios without proportionally increasing overall device volume and complexity.
Solution Approach 2:
The hollow shaft serves multiple functions: it provides structural support for the clutch module, contains internal passageways for conducting pressurized fluid to all three clutch packs, and acts as a mounting structure for the piston assemblies. This multi-functionality reduces the need for separate components, thereby managing versatility while controlling device complexity.
2Volume of moving object
If pistons extend through openings in other clutch packs to apply force, then space is efficiently utilized, but manufacturing precision requirements increase
Solution Approach 1:
The first piston is designed to extend through openings in the pressure plate, separator plates, and reaction plate of the second clutch pack to reach and apply force to the first clutch pack. This nested arrangement allows the piston to pass through components of an adjacent clutch pack without requiring separate housing structures, efficiently utilizing the axial space within the transmission assembly and reducing the overall volume of the clutch module.
Solution Approach 2:
The openings in the second clutch pack components serve as intermediaries that allow the first piston to access the first clutch pack. These openings are precisely formed in the pressure plate, separator plates, and reaction plate, providing a guided path for the piston while maintaining the structural integrity of the second clutch pack. This intermediary structure enables space-efficient design while managing manufacturing precision requirements through standardized opening configurations.
3Reliability
If unpressurized fluid is conducted to balance chambers, then unintended clutch engagement is prevented, but the device complexity increases with additional passageways
Solution Approach 1:
Unpressurized fluid is conducted through dedicated passageways in the hollow shaft to balance chambers that counteract centrifugal forces acting on the clutch packs during rotation. By providing this preliminary anti-action through balanced fluid pressure, the system prevents unintended clutch engagement before it can occur, thereby enhancing reliability. The passageways are integrated into the existing hollow shaft structure, minimizing additional complexity while ensuring proper clutch engagement control.
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 configuration allows for efficient power transmission across various speed ratios, enhancing acceleration at low speeds and fuel efficiency at high speeds by selectively engaging clutch packs through fluid pressure, while preventing unintended clutch engagement.
Implementation Method 1
Passageways within the hollow shaft may transmit pressurized fluid to apply chambers for each of the clutches
Implementation Method 2
An additional passageway may transmit unpressurized fluid to balance chambers
Data Source
AI summary
A transmission utilizes a three clutch module. The clutch module may be pre-assembled before it is assembled into the transmission. All three clutch packs are splined to a common shell at their outer diameter. One of the clutch pistons passes through openings in the clutch pack of one of the other clutches. The common shell is fixedly coupled to a hollow shaft through which the transmission input shaft protrudes. Pressurized fluid to engage the three clutches is routed through axial passageways in the input shaft.