AWD Coupling Slack Adjuster for Fast Reconnection
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Solution Overview
Problem
In AWD vehicles, quickly resuming the connected state of hydraulic disc couplings from a fully disconnected state is challenging due to wear of discs, leading to increased connect time and fuel consumption.
Innovation Solution
A coupling slack adjuster mechanism that establishes a rest position for the hydraulic piston in disconnect mode, using primary and secondary slack adjuster sleeves with a return spring to manage piston stroke and maintain proper slack, regardless of disc wear, allowing for faster reconnection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the play between neighboring discs is increased to 0.08-0.10 mm to minimize drag torque, then the coupling can be properly disconnected, but the piston stroke becomes considerable and the connect time increases
Solution Approach 1:
The patent introduces a dynamic adjustment mechanism that allows the piston stroke to be automatically compensated based on disc wear. The adjustment mechanism includes threads that enable incremental positioning of the piston, dynamically adapting the stroke length to maintain optimal play (0.08-0.10 mm) while minimizing connect time regardless of disc wear condition
Solution Approach 2:
The patent changes the parameter of piston stroke length from a fixed value to an adjustable variable. By providing threading and adjustment mechanisms, the system can modify the piston stroke parameter to compensate for disc wear, thereby maintaining the optimal play gap while reducing the time required to reconnect the coupling
2Reliability
If disc wear occurs in the coupling, then the piston stroke becomes even longer, but this results in even longer connect time from disconnect mode
Solution Approach 1:
The patent implements a self-adjusting mechanism where the system automatically compensates for disc wear through its adjustment mechanism. The threading and positioning features allow the coupling to self-regulate the piston stroke length, eliminating the need for external intervention and maintaining optimal performance despite disc wear over time
Solution Approach 2:
The patent provides for preliminary adjustment of the piston stroke before significant wear affects performance. The adjustment mechanism allows proactive compensation for anticipated wear, enabling the system to maintain optimal connect time and play gap before wear becomes a critical issue
3Loss of time
If the piston stroke is reduced to minimize connect time, then the connect mode is reached faster, but the play between discs becomes insufficient and drag torque increases
Solution Approach 1:
The patent changes the piston stroke from a fixed short distance to an adjustable parameter that can be optimized for each operating condition. The adjustment mechanism enables the stroke length to be precisely controlled to maintain the optimal play gap (0.08-0.10 mm), thereby minimizing drag torque while achieving fast connect times
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 solution minimizes the connect time of the coupling even with worn discs, reducing fuel consumption and ensuring efficient operation between drive modes.
Implementation Method 1
a return spring or disconnect spring with a lower force than the force of the press fit
Implementation Method 2
a hydraulic piston for pressing the disc package together under the action of hydraulic pressure
Implementation Method 3
a primary slack adjuster sleeve, which by press fit connection to a member in the coupling and by working relationship with the piston
Data Source
AI summary
A coupling for an AWD vehicle comprises a disc package with alternate discs, which are connected for rotation with, but are axially movable in relation to an ingoing and an outgoing axle, respectively, of the coupling, and a hydraulic piston for pressing the disc package together under the action of hydraulic pressure, hereby establishing a connect mode, in which the ingoing axle is connected to the outgoing axle. A coupling slack adjuster is provided for mechanically establishing a rest position for the hydraulic piston in a disconnect mode, in which a predetermined slack in the disc package is established, irrespective of the wear of the discs.