Torque Converter Blade Notch Geometry for Stress Relief
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Solution Overview
Problem
The existing blade assemblies in torque converters experience stress and reduced durability due to fluid flow direction, which affects their service life.
Innovation Solution
A blade assembly design featuring blades with a curved portion, a curved region axially spaced from the curved portion, and an end with a notch radially closer to the curved region, where the end includes a lip extending from the curved region to the notch, and an axially extending tab connecting to a core ring, reducing stress by altering the fluid flow distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If blades are arranged around the inner surface of the shell to direct fluid flow, then the torque converter can transmit torque effectively, but stress on the blades increases which reduces durability and service life
Solution Approach 1:
The patent applies local quality by introducing a notch at a specific location on each blade (radially closer to the curved region than to the curved portion). This localized structural modification changes the stress distribution characteristics at that specific point, making the blade more resistant to fatigue while maintaining its overall torque transmission function.
Solution Approach 2:
The patent changes the geometric parameters of the blade by adding a notch with specific dimensions (radius between 2mm and 5mm, depth of 2.5mm). This parameter change alters the stress distribution pattern in the blade, reducing peak stresses and improving durability without significantly affecting the blade's primary function of directing fluid flow.
2Ease of manufacture
If blades are attached to the shell by brazing, then the blade assembly can be manufactured efficiently, but the stress concentration at attachment points reduces blade service life
Solution Approach 1:
The notch is strategically positioned to create a stress relief zone that complements the brazed attachment structure. By placing the notch radially closer to the curved region, the design creates a gradual stress transition zone that reduces stress concentration at the brazed attachment points, thereby extending service life while maintaining manufacturing efficiency.
Solution Approach 2:
The notch acts as a preemptive stress relief feature that cushions against stress concentrations before they can propagate through the blade structure. This beforehand cushioning effect prevents fatigue crack initiation at critical locations, particularly near the brazed attachments, thereby extending the operational life of the blades.
Data Source
AI summary
A blade assembly for a torque converter includes a shell defining an inner surface and a plurality of blades arranged around the inner surface of the shell. The plurality of blades each include a curved portion contacting the inner surface. The plurality of blades each further include a curved region axially spaced from the respective curved portion. The plurality of blades each further include an end extending from the respective curved portion to the respective curved region. Each end includes a notch arranged radially closer to the respective curved region than to the respective curved portion.