Torque Converter Clutch Piston Positioning for Smoother Lock-Up
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Solution Overview
Problem
Existing launch devices, such as torque converters, face challenges in managing axial movement of the clutch piston, leading to inefficient engagement and disengagement of the clutch, resulting in vibrations and noise during transitions between drive and coast modes, which current systems have failed to address effectively in conventional setups.
Innovation Solution
A mechanical clutch piston positioner is introduced, featuring a first interface connected to the clutch piston and a second interface associated with the damper or output hub, allowing for axial and rotational relative movement to position the clutch piston toward the front cover during coast mode, thereby minimizing vibrations and noise during transitions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the clutch piston is allowed to move axially freely in response to axial forces during coast mode, then the clutch piston can return to its disengaged position, but the engagement time increases and vibrations occur during mode transitions
Solution Approach 1:
The positioner mechanism pre-positions the clutch piston near the front cover during coast mode, so that when drive mode is engaged, the piston is already close to its engagement position. This preliminary positioning action significantly reduces the engagement time and eliminates the delay that would otherwise occur while the piston travels from its disengaged position.
Solution Approach 2:
The positioner acts as an intermediary mechanism between the clutch piston and the front cover. It provides a controlled mechanical connection that maintains the piston in a predetermined position during coast mode, mediating between the axial forces that push the piston away and the need for rapid engagement during drive mode.
2Productivity
If the clutch piston is positioned closer to the front cover during coast mode, then engagement is faster, but the axial movement distance increases
Solution Approach 1:
The positioner mechanism pre-positions the clutch piston near the front cover during coast mode, so that when drive mode is engaged, the piston is already close to its engagement position. This preliminary positioning action significantly reduces the engagement time and eliminates the delay that would otherwise occur while the piston travels from its disengaged position.
3Object-affected harmful factors
If a mechanical positioner is added to control clutch piston position, then vibrations and noise are reduced, but the device complexity increases
Solution Approach 1:
The positioner acts as an intermediary mechanism between the clutch piston and the front cover. It provides a controlled mechanical connection that maintains the piston in a predetermined position during coast mode, mediating between the axial forces that push the piston away and the need for rapid engagement during drive mode.
Solution Approach 2:
The positioner mechanism is designed to be self-actuating through the existing axial forces and hydraulic pressure in the system. During coast mode, axial forces automatically position the piston near the front cover through the positioner mechanism, eliminating the need for external actuators or complex control systems.
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 mechanical clutch piston positioner ensures smooth and immediate engagement of the lock-up clutch during drive mode transitions, reducing vibrations and noise, and maintaining system stability by accurately positioning the clutch piston, enhancing the overall performance of the launch device.
Implementation Method 1
a plurality of biasing members coupling the input member to the output member for relative rotation therebetween
Implementation Method 2
hydraulic fluid within the chamber is forced radially outward, under centrifugal forces, then forward (toward the engine in a typically configuration) by the blades of the impeller
Implementation Method 3
The forwardly directed fluid impacts blades of a turbine, which are opposed to the blades of the impeller. The force of the hydraulic fluid impacting the turbine blades, in conjunction with the shape of the turbine blades, causes the turbine to rotate
Data Source
AI summary
A launch device having a front cover connectable to the output of a prime mover, an output hub connectable to the input of the transmission, an impeller driven in rotation with the front cover and a turbine fluidly coupled in rotation with the impeller. A damper includes an output member connected to and rotatable with the output hub. A lock-out clutch, when engaged, rotationally locks the damper with the front cover and includes a clutch piston which is axially and rotationally moveable relative to the output hub. A mechanical clutch piston positioner includes first and second interfaces individually associated with either the clutch piston or one of the output member or output hub. The first interface is axially and rotationally moveable relative to the second interface. Upon the first interface overrunning tire second interface, mechanical engagement of the interfaces axially positions tire clutch piston toward the front cover.