Transmission Brake Hub Structure for Deformation and Leakage Control
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Solution Overview
Problem
In automatic transmissions, the deformation of the hub member during brake engagement leads to reduced positional accuracy and potential hydraulic fluid leakage, causing poor brake operation.
Innovation Solution
The hub member is designed with a configuration where the engagement and disengagement hydraulic chambers are radially inward of the friction plates, and the first and second coupling members are positioned radially inward of the disengagement hydraulic chamber, reducing radial spacing and minimizing deformation. Additionally, a biasing member ensures accurate piston movement, and an oil supply passage enhances lubrication efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the engagement and disengagement hydraulic chambers are disposed radially inward of the friction plates to downsize the automatic transmission, then the radial spacing is reduced and deformation is minimized, but the structural complexity increases due to the multi-component hub member configuration
Solution Approach 1:
The hub member is divided into multiple components: a first hub member having a cylindrical part spline-engaged with the friction plates and transmission case, a second hub member fitted into the transmission case, and a third hub member forming the engagement hydraulic chamber. These segmented components are coupled together axially, allowing the hydraulic chambers to be positioned radially inward while maintaining functional separation and reducing overall radial spacing.
Solution Approach 2:
The second hub member is fitted into the transmission case in a nested arrangement, while the first and third hub members are coupled axially to form an integrated assembly. This nesting approach allows compact positioning of the hydraulic chambers radially inward without increasing the overall radial envelope of the brake assembly.
2Volume of moving object
If the first and second coupling members are disposed radially inward of the disengagement hydraulic chamber, then the radial spacing is further reduced, but the manufacturing precision requirements increase to ensure proper alignment and prevent deformation
Solution Approach 1:
The coupling members are specifically positioned radially inward of the disengagement hydraulic chamber rather than being uniformly distributed, concentrating the structural connection points in a region that optimizes both compactness and structural integrity. This localized arrangement reduces radial spacing while managing precision requirements through strategic placement.
3Ease of operation
If slip control of the brake is frequently performed during vehicle start, then smooth start is achieved while avoiding engine stall, but heat generation of friction plates increases
Solution Approach 1:
Hydraulic fluid is supplied to the friction plates through the hub member structure to provide cooling during frequent slip control operations. The hydraulic system absorbs and dissipates the heat generated during slip control, enabling repeated smooth starts without excessive temperature buildup in the friction plates.
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 suppresses hub member deformation, maintains piston accuracy, prevents hydraulic fluid leakage, and improves brake operation by ensuring efficient lubrication and cooling of friction plates.
Implementation Method 1
the hydraulic oil for lubrication supplied to the friction plates... cooling performance... heat generation of friction plates
Implementation Method 2
the hydraulic oil, which is moved to the drum member side by a centrifugal force of the friction plates
Data Source
AI summary
An automatic transmission with a brake is provided, the brake including a hub member coupled to a transmission case. The hub member includes a first hub member having a cylindrical part spline-engaged with friction plates and the transmission case, and forming a disengagement hydraulic chamber, a second hub member disposed at one side of the first hub member in the axial direction, fitted into the transmission case, and coupled to the one side of the first hub member in the axial direction by a first coupling member, and a third hub member disposed at the other side of the first hub member in the axial direction, coupled to the other side of the first hub member in the axial direction by a second coupling member, and forming an engagement hydraulic chamber. The first coupling member and the second coupling member are disposed radially inward of the disengagement hydraulic chamber.