Torque Converter Hub Plenum Groove Fluid Flow
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Solution Overview
Problem
Conventional torque converter hub assemblies experience flow restrictions and pressure loss during clutch engagement, leading to delayed clutch response and reduced controllability due to the isolation of flow paths and pressure differences across the piston.
Innovation Solution
A cross-drilled hub assembly with a circumferential plenum groove between two seals, allowing for unobstructed fluid flow and pressure equalization between the inner and outer radial surfaces, enhancing clutch controllability by mitigating flow restrictions and maintaining consistent back pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If flow paths are isolated between hubs by seals, then clutch controllability is improved through pressure differential, but fluid flow restriction and pressure loss occur causing delayed clutch response
Solution Approach 1:
The hub is segmented into multiple chambers (first back pressure chamber, second back pressure chamber, apply chamber) separated by seals, with dedicated flow paths for each chamber. This segmentation allows independent pressure control in each region, enabling precise clutch controllability while maintaining efficient fluid flow through dedicated channels that prevent cross-contamination and pressure loss between chambers.
Solution Approach 2:
A plenum chamber is introduced as an intermediary element between the first and second back pressure chambers. This plenum chamber receives fluid from the first back pressure chamber and supplies it to the second back pressure chamber, acting as a buffer and pressure equalization zone that eliminates flow restrictions and pressure losses while maintaining the necessary pressure differentials for clutch controllability.
2Ease of operation
If piston moves towards back pressure chamber during engagement, then clutch engagement is achieved, but back pressure chamber reduces in size causing fluid evacuation without pressure buildup
Solution Approach 1:
The plenum chamber is pre-configured with sufficient volume and fluid supply pathways before piston movement begins. As the piston moves towards the back pressure chamber, the plenum chamber already contains adequate fluid volume and has open flow paths from the first back pressure chamber, allowing immediate pressure equalization without evacuation delays. This preliminary preparation ensures continuous pressure support during the engagement process.
Solution Approach 2:
The plenum chamber is nested within the hub structure, concentric with the piston axis, and positioned between the two back pressure chambers. This nested configuration allows the plenum chamber to expand and contract with piston movement while maintaining its function as a pressure buffer, effectively nested within the overall hub assembly to provide continuous fluid reservoir and pressure equalization during engagement.
3Stress or pressure
If cross over interface chokes flow, then back pressure is created in piston, but clutch response time is delayed
Solution Approach 1:
The flow restriction problem at the cross over interface is eliminated by extracting the choke point and replacing it with a dedicated, open flow path through the plenum chamber. The plenum chamber provides a direct, unrestricted passage for fluid between the first and second back pressure chambers, removing the chocking effect that previously caused flow restriction and delayed response time while maintaining necessary back pressure for clutch engagement.
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 plenum groove design improves clutch controllability by facilitating smooth fluid transfer and pressure management, reducing delays and pressure losses during clutch engagement and disengagement, thereby enhancing transmission performance.
Implementation Method 1
The channel extends radially into the plenum groove... allowing for unobstructed fluid flow and pressure equalization between the inner and outer radial surfaces
Implementation Method 2
The flow paths in these hubs cause a delay and pressure loss/bump as piston 28 is being engaged... causing a pressure difference between the apply chamber and the back pressure chamber applying clutch 32 with a force relative to the differential pressure
Data Source
AI summary
A hub assembly for a torque converter is provided. The hub assembly includes a turbine hub including an inner radial surface, an outer radial surface and a channel for providing fluid from the inner radial surface to the outer radial surface. The turbine hub also includes a first seal and a second seal on the outer radial surface and a plenum groove in the outer radial surface axially between the first seal and the second seal. The channel extends radially into the plenum groove. A method for forming a hub assembly for a torque converter is also provided.