Automatic Transmission Input Shaft Strength and Oil Flow
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Solution Overview
Problem
The General Motors Powerglide transmission's input shaft is prone to breakage under high horsepower and torque conditions due to stress risers created by circumferential oil seal grooves, which also disrupt oil flow and torque converter pressure, leading to inadequate cooling and lubrication.
Innovation Solution
The input shaft is strengthened by increasing its diameter and removing oil seal grooves, with a radially extending stator support flange that transfers torque and includes internal oil passages to maintain proper oil flow and pressure, and the oil seals are repositioned to ensure effective oil routing without compromising the shaft's strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If circumferential oil seal grooves are provided on the input shaft, then oil flow control between the stator support shaft and input shaft is achieved, but stress risers are created that lead to input shaft breakage under high torque conditions
Solution Approach 1:
The patent removes the circumferential oil seal grooves from the input shaft entirely, extracting the problematic feature that caused stress risers and shaft breakage. Oil sealing is achieved through alternative means without requiring grooves in the shaft itself.
Solution Approach 2:
The patent introduces an intermediary oil seal arrangement between the stator support shaft and input shaft that does not require grooves in the input shaft. The oil seal is positioned and supported in a manner that eliminates the need for weakening grooves while still providing the necessary sealing function.
2Strength
If input shaft diameter is increased to strengthen the shaft, then power handling capacity is improved, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent applies local quality by strengthening the input shaft only in the specific regions where torque loads are highest, rather than uniformly increasing the entire shaft diameter. This allows the shaft to maintain adequate strength while minimizing manufacturing complexity and material usage.
Data Source
AI summary
A shaft system for an automatic transmission includes a stator support shaft having an internal axial bore for receiving an input shaft, a forward engagement portion for engaging a stator of a torque converter of the automatic transmission and an integral stator support flange extending radially outward for engaging a stator support of the automatic transmission and transferring to the stator support substantially all of a torque load imposed on the stator support shaft by the stator. The stator support flange includes at least one oil flow bore positioned therein to supply oil between different components of the transmission.