Hydrokinetic Torque Coupling Lock-Up Clutch Axial Stability
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Solution Overview
Problem
Hydrokinetic torque coupling devices with lock-up clutches face issues where axial forces generated by transmission fluid can prematurely disengage the turbine-piston from the impeller, especially during downhill driving, leading to unintended lock-up disengagement or failure to engage in coasting conditions, due to spatial constraints and functional inefficiencies.
Innovation Solution
A hydrokinetic torque coupling device design that includes a casing with an impeller and turbine-piston, a damper assembly with elastic coupling, and a clutch member with a connecting member that allows axial displacement of the turbine-piston to engage and disengage the lock-up mode, ensuring mechanical locking between the casing and turbine-piston, thereby stabilizing the coupling under varying conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the turbine-piston is allowed to axially displace for lock-up engagement, then mechanical coupling reliability is improved, but axial forces from transmission fluid can cause premature disengagement
Solution Approach 1:
The spring element applies a preliminary axial force to bias the turbine-piston toward the impeller, counteracting the axial forces generated by transmission fluid that tend to move the turbine-piston away from the impeller. This preliminary counter-action prevents premature disengagement of the lock-up clutch during coasting conditions.
Solution Approach 2:
The spring element acts as an intermediary between the turbine-piston and the impeller, providing a controlled axial force that maintains proper engagement while allowing necessary axial displacement. This mediator enables the turbine-piston to respond to hydrodynamic forces while maintaining stable lock-up engagement.
2Productivity
If the turbine-piston is hydro-dynamically drivable by the impeller, then torque transmission efficiency is improved, but axial forces can move the turbine-piston away from the impeller causing untimely disengagement
Solution Approach 1:
The spring element provides a preliminary counteracting force against the axial forces generated during hydrodynamic torque transmission, preventing the turbine-piston from moving away from the impeller and ensuring timely and reliable lock-up engagement.
Solution Approach 2:
The spring element modifies the axial force parameters acting on the turbine-piston, creating a balanced force system that allows hydrodynamic torque transmission while preventing premature disengagement. The spring constant and pre-load are optimized to maintain proper engagement under varying torque and speed conditions.
3Device complexity
If the connecting member extends through the damper assembly to interconnect clutch plate with turbine-piston, then component consolidation is achieved, but spatial constraints and functional inefficiencies occur
Solution Approach 1:
The connecting member is segmented into portions that pass through the damper assembly rather than being rigidly attached, allowing the damper to flex and move independently while maintaining the connection between the clutch plate and turbine-piston. This segmentation enables both consolidation and operational freedom.
Solution Approach 2:
The connecting member is designed to accommodate dynamic movement through the damper assembly, allowing axial displacement of the turbine-piston while maintaining connection. This dynamic design enables the system to adapt to varying operational conditions while maintaining component consolidation.
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 design enhances the reliability and efficiency of the hydrokinetic torque coupling by maintaining a stable lock-up mode under different driving conditions, reducing spatial requirements, and allowing for consolidation of components, resulting in a more compact and effective driveline system.
Implementation Method 1
a driven member elastically coupled to the drive member
Implementation Method 2
a damper assembly and a clutch member
Implementation Method 3
the clutch member and the casing frictionally interlock with one another, so that the casing is mechanically locked to and non-rotatable relative to the turbine-piston
Implementation Method 4
the action of the transmission fluid generates axial forces, which tend to move the turbine-piston away from the impeller
Data Source
AI summary
A hydrokinetic torque coupling device features a casing comprising a casing shell and an impeller shell, an impeller, a turbine-piston, a damper assembly comprising a drive member non-moveably connected to the turbine-piston and a driven member elastically coupled to the drive member, and a clutch member comprising a clutch plate and a connecting member extending through the damper assembly and non-moveably interconnecting the clutch plate with the turbine-piston. The clutch plate has an axially outer surface facing an engagement surface of the casing. The turbine-piston is axially displaceable relative to the casing to move the clutch member axially toward and away from the engagement surface of the casing for positioning the hydrokinetic torque coupling device into and out of a lockup mode in which the clutch member and the casing frictionally interlock with one another so that the casing is non-rotatable relative to the turbine-piston.