Automatic Transmission Brake Separator Spline Relocation
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Solution Overview
Problem
Hydraulically-actuated automatic transmissions face challenges with high drag losses due to direct splining of brake separator plates to the transmission case, leading to increased costs and complexity in machining spline teeth, and inefficient fluid evacuation, which negatively impacts fuel economy and assembly processes.
Innovation Solution
The design optimizes the placement of brakes, clutches, and gearsets, with brake servos in a support and clutch servos in a housing, minimizing axial length and housing costs by stacking clutches and reducing the number of splines in the transmission case, and utilizing axial feed passages for efficient fluid distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If brake separator plates are splined directly to the transmission case, then the brake assembly is structurally stable, but automatic transmission fluid evacuation becomes difficult leading to high drag losses
Solution Approach 1:
The brake assembly is separated from the transmission case by introducing a pump support component. The separator plates are splined to the pump support rather than directly to the transmission case, creating a segmented structure that allows fluid to be evacuated more efficiently while maintaining brake structural stability.
Solution Approach 2:
The pump support acts as an intermediary component between the transmission case and the brake separator plates. This intermediate structure enables proper fluid evacuation pathways while maintaining the structural connection needed for brake operation, thereby reducing drag losses without compromising manufacturing ease.
2Device complexity
If brake separator plates are splined directly to the transmission case, then the brake structure is simplified, but installation must be completed as a final assembly increasing complexity
Solution Approach 1:
The brake assembly can now be manufactured and assembled as a separate subassembly on the pump support, then installed into the transmission as a unit. This segmentation of the assembly process reduces overall device complexity by allowing modular construction while maintaining structural simplicity of the brake components themselves.
Solution Approach 2:
The brake subassembly can be pre-assembled and tested separately before final installation in the transmission. This preliminary action allows for quality control and simplification of the final assembly process, reducing the complexity of manufacturing the complete transmission assembly.
3Ease of manufacture
If spline teeth are formed in the transmission case, then direct connection is achieved, but machining costs increase and scrap production increases
Solution Approach 1:
The spline connection functionality is extracted from the transmission case and relocated to the pump support component. This extraction eliminates the need to machine spline teeth in the transmission case, thereby reducing machining costs and preventing the generation of excessive scrap material from the transmission case.
Solution Approach 2:
Instead of forming expensive spline teeth in the transmission case, the patent uses a copied or replicated spline structure on the pump support that achieves the same connection function. This alternative approach reduces manufacturing costs and material waste while maintaining the necessary mechanical connection.
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 reduces drag losses, minimizes housing and length costs, and simplifies assembly by allowing for a more efficient fluid supply and reduced spline formation, thereby enhancing fuel economy and reducing scrap production.
Implementation Method 1
hydraulically-actuated clutches
Implementation Method 2
pressure feeds for each clutch-apply circuit and respective feeds to balance volumes
Implementation Method 3
brakes each actuated by one of the brake servos for producing a connection between the support and a respective gearset member
Implementation Method 4
clutches each actuated by one of the clutch servos for producing a drive connection between the housing and a respective gearset member
Data Source
AI summary
A transmission includes gearsets each including rotating members, a support held against rotation, brake servos located in the support, brakes each actuated by one of the brake servos for producing a connection between the support and a respective gearset member, a housing, clutch servos located in the housing, and clutches each actuated by one of the clutch servos for producing a drive connection between the housing and a respective gearset member.