Double Diaphragm Spring Engagement for Torque Converter Coasting
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Solution Overview
Problem
Single coast engagement diaphragm springs in torque converters often face limitations due to excessive hysteresis during drive conditions and insufficient thrust load during coasting conditions, which can hinder effective engagement of the lockup clutch.
Innovation Solution
A double coast engagement diaphragm spring system comprising a first and second coast engagement diaphragm spring, a spacer ring, and a drive flange with ramps, where the first spring provides continuous axial thrust and the second spring applies additional thrust during coasting, with a retainer plate disengaging the second spring during drive conditions to prevent excessive torque.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single coast engagement diaphragm spring is used, then the device complexity is reduced, but the thrust load during coasting conditions becomes insufficient
Solution Approach 1:
The single diaphragm spring is segmented into two separate coast engagement diaphragm springs (first and second springs). Each spring is positioned at different angular locations around the drive flange and engages with corresponding ramps. This segmentation allows each spring to contribute independently to the total thrust load during coasting conditions, thereby increasing the overall force capability while maintaining a relatively simple overall structure.
2Ease of manufacture
If a single coast engagement diaphragm spring is used, then the manufacturing cost is reduced, but excessive hysteresis occurs during drive conditions
Solution Approach 1:
By dividing the single spring into two separate springs positioned at different angular locations, the system reduces the hysteresis effect during drive conditions. The segmented configuration allows for better load distribution and reduced internal friction within each individual spring, thereby decreasing energy loss through hysteresis while maintaining manufacturing simplicity.
Solution Approach 2:
The two diaphragm springs are positioned at different angular locations around the drive flange, creating local quality variations in the force application. This spatial distribution optimizes the local stress and strain conditions for each spring during drive conditions, reducing overall hysteresis while keeping the manufacturing process straightforward.
3Force
If additional thrust load is applied during coasting, then the lockup clutch engagement is improved, but excessive torque is introduced during drive conditions
Solution Approach 1:
The system dynamically engages and disengages the second diaphragm spring based on operating conditions. During coasting, both springs are engaged to provide maximum thrust load for clutch engagement. During drive conditions, the second spring is disengaged via the retainer plate, preventing excessive torque. This dynamic configuration allows the system to adapt its force characteristics to the specific operating mode.
Solution Approach 2:
The retainer plate acts as an intermediary mechanism that controls the engagement and disengagement of the second diaphragm spring. It mediates between the need for high thrust during coasting and the need to limit torque during drive, automatically switching the configuration based on the operational state without requiring external control.
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
The double coast engagement diaphragm spring system ensures consistent engagement of the lockup clutch during both drive and coasting conditions, overcoming the limitations of single spring systems by providing combined axial thrusts to manage turbine loads effectively.
Implementation Method 1
a first coast engagement diaphragm spring configured to exert a first, continuous axial thrust onto a turbine of the torque converter; a second coast engagement diaphragm spring configured to apply a second axial thrust onto the turbine
Data Source
AI summary
An apparatus and methods for a double coast engagement diaphragm spring for a torque converter are provided. The double coast engagement diaphragm spring includes first and second coast engagement diaphragm springs. The first coast engagement diaphragm spring exerts a first, continuous axial thrust onto a turbine comprising the torque converter. The second coast engagement diaphragm spring applies a second axial thrust onto the turbine only during coasting conditions. A drive flange includes ramps for engaging the second coast engagement diaphragm spring during coasting conditions and causing the second coast engagement diaphragm spring to apply the second axial thrust onto the turbine. A retainer plate disengages the second coast engagement diaphragm spring during drive conditions. A spacer ring between the first coast engagement diaphragm spring and the second coast engagement diaphragm spring causes the first and second coast engagement diaphragm springs to operate in series.