Transmission Assembly Front Support Brake Integration
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Solution Overview
Problem
Existing automatic transmission systems face challenges in efficiently managing speed ratios across a wide range of vehicle speeds, particularly in low-speed conditions where engine torque multiplication is required for acceleration, and high-speed conditions for fuel-efficient cruising.
Innovation Solution
The transmission design incorporates two brakes with clutch packs and a planetary gear set, where the inner brake holds the sun gear and the outer brake holds the ring gear against rotation, utilizing a shift element module with a housing and return spring arrangement to selectively engage and disengage clutch packs for various speed ratios.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple clutch packs and pistons are integrated into a single housing module, then the transmission can achieve multiple speed ratios with improved compactness, but the assembly complexity and manufacturing precision requirements increase
Solution Approach 1:
The transmission system is divided into modular clutch packs, each with its own piston and housing section. The first clutch pack with first piston and second clutch pack with second piston are assembled as separate modules within the housing, allowing independent assembly and maintenance while achieving multiple speed ratios through selective engagement of these modular units.
Solution Approach 2:
The clutch packs are nested within the transmission housing in a compact arrangement where the first and second clutch packs are positioned concentrically or adjacently within the same housing space. This nesting approach allows multiple clutch assemblies to occupy shared space, reducing overall transmission size while maintaining the capability for multiple speed ratios.
2Power
If clutch packs are compressed between reaction plates and pistons, then efficient torque transmission is achieved, but the manufacturing precision and assembly difficulty increase
Solution Approach 1:
The clutch packs are designed to self-align and self-compress within the housing. The reaction plates and pistons are configured with tapered surfaces or cam mechanisms that automatically guide the clutch pack compression and maintain proper engagement force without requiring high-precision manual adjustment during assembly, thereby reducing assembly difficulty while maintaining torque transmission efficiency.
Solution Approach 2:
The clutch pack compression force and engagement characteristics are optimized by varying material properties, friction coefficients, and geometric parameters of the clutch plates and pistons. This allows the system to achieve efficient torque transmission through controlled parameter variations rather than relying solely on high manufacturing precision.
3Ease of operation
If radial fingers extend through axial fingers to provide reaction points, then the return spring arrangement can effectively react against the reaction plate, but the structural complexity and potential failure points increase
Solution Approach 1:
Instead of having the reaction plate pass through the radial fingers, the design inverts the arrangement where radial fingers extend through axial fingers to provide the reaction point. This inverted configuration allows the return spring to directly engage with the reaction plate while maintaining structural integrity and reducing the number of separate fastening elements required.
Solution Approach 2:
The radial and axial fingers are combined into an integrated structural feature of the reaction plate and housing assembly. This merging of finger elements creates a unified load path for the return spring force while reducing the total number of discrete parts and potential failure points compared to having separate radial and axial finger components.
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 allows for efficient power transmission across a range of speed ratios, enhancing acceleration and fuel efficiency by enabling precise control of clutch engagement and disengagement through hydraulic pressure, thereby optimizing transmission performance.
Implementation Method 1
A return spring arrangement for the second piston reacts against the reaction plate of the first brake
Implementation Method 2
To engage the clutch, hydraulic pressure is applied to a piston which, in turn, applies axial force to a separator plate on one end of the clutch pack
Data Source
AI summary
Two brakes of a transmission utilize the transmission front support as a clutch housing. One brake, which selectively holds a sun gear against rotation, is located on the inside of a cylindrical wall of the front support. A second brake, which selectively holds a ring gear against rotation, is located on the outside of the cylindrical wall. The clutch pack of the inner brake is splined to the inner surface of the cylindrical wall. The reaction plate of the first clutch pack includes radial fingers that extend between axial fingers of the cylindrical wall. The portion of the reaction plate that extends to the outer side of the cylindrical wall provides a reaction for a return spring of the outer brake.