Torque Converter Stator Blade Geometry for Cavitation Resistance
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Solution Overview
Problem
Torque converters with reduced axial width face challenges such as non-uniform flow areas, which can lead to cavitation and reduce their performance and lifespan, while also occupying more space than necessary in transmission assemblies.
Innovation Solution
The torque converter features a stator with curved blades that narrow as they extend from the shell to the core, and include non-ruled surfaces, which alter the three-dimensional flow field to equalize pressure and reduce cavitation potential.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the torque converter axial width is reduced to save space, then the space occupancy is reduced, but non-uniform flow areas are created leading to cavitation and reduced performance
Solution Approach 1:
The blade geometry is varied locally along its span, with the blade narrowing from root to tip and featuring non-ruled (curved) surfaces. This local variation in blade cross-section creates a corresponding variation in flow area that compensates for the reduced axial width, maintaining uniform flow distribution and preventing cavitation in the compact torque converter design.
Solution Approach 2:
The patent employs non-ruled surfaces on the blades, which introduces complex three-dimensional curvature to the blade geometry. This curvature allows the blades to efficiently guide fluid flow through the compact axial space while maintaining uniform flow areas, thereby preventing cavitation despite the reduced overall torque converter width.
2Reliability
If the blade meridonial length at the shell is increased by a factor of 2-6 to create narrowing blades, then cavitation is mitigated, but the manufacturing complexity increases
Solution Approach 1:
The non-ruled surfaces with three-dimensional curvature can be manufactured using modern成型 techniques such as precision casting or CNC machining. These methods are capable of producing complex curved geometries with consistent accuracy, making the manufacturing process feasible despite the increased geometric complexity required to achieve the narrowing blade profile.
3Volume of moving object
If the torque converter is designed with a compact oblong profile (width/height ratio of 0.75), then space efficiency is improved, but the flow uniformity becomes more difficult to maintain
Solution Approach 1:
The narrowing blade geometry with non-ruled surfaces creates local variations in flow passage area that compensate for the compact oblong overall shape. By carefully designing the blade cross-section to narrow from root to tip, the flow area is maintained uniformly throughout the compact torque converter, ensuring stable and uniform flow fields despite the reduced width/height ratio of 0.75.
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 design mitigates cavitation, enhances the torque converter's performance, increases its cavitation threshold, and allows for a more compact design, thereby improving power density in transmission assemblies.
Implementation Method 1
curved blades that narrow as they extend from the shell to the core, and include non-ruled surfaces, which alter the three-dimensional flow field to equalize pressure and reduce cavitation potential
Data Source
AI summary
A torque converter, which may be found in an automotive transmission, is provided. In some examples, the torque converter includes a shell that extends about an axis of rotation, a core that extends about the axis of rotation, and a plurality of curved blades that extend contactedly from the shell to the core. At least one blade of the plurality of curved blades may include a non-ruled surface. The at least one blade of the plurality of curved blades may narrow as it extends from the shell to the core.