Transfer Case Lubrication Control for Shutdown Shaft
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Transfer case arrangements with shutdown devices for secondary output shafts face lubrication issues when the secondary output shaft is shut down, leading to potential damage due to lack of lubrication oil, and existing pump-less solutions do not adequately address this problem.
Innovation Solution
A control system activates an oil conveying device intermittently to ensure lubrication oil is delivered to the clutch and bearings even when the secondary output shaft is shut down, using a chain drive or gear connection to convey oil from the oil sump to the transfer case components, and an oil reservoir ensures continuous lubrication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the second output shaft is shut down when the clutch is disengaged, then drag losses and moments of inertia are reduced, but lubrication of the clutch and bearings deteriorates
Solution Approach 1:
The patent implements periodic activation of the oil conveying device (pump) even when the second output shaft is shut down. The control device activates the pump at predetermined time intervals to ensure continuous lubrication of the clutch and bearings, while maintaining the shutdown state to minimize drag losses. This periodic action resolves the contradiction by providing lubrication only when necessary rather than continuously.
2Reliability
If an electrically driven pump continuously conveys lubrication oil, then lubrication is ensured, but efficiency of the transfer case deteriorates
Solution Approach 1:
Instead of continuous pump operation, the patent employs periodic activation controlled by a control device that activates the pump at predetermined time intervals. This reduces energy consumption significantly while maintaining adequate lubrication levels in the oil sump and on clutch/bearing surfaces.
Solution Approach 2:
The system uses the existing kinetic energy of the first output shaft and clutch assembly to naturally distribute lubrication oil during periods when the pump is not active. The continuous slow movement of components during normal operation provides self-lubrication, reducing the need for active pumping.
3Loss of energy
If a pump-less lubrication device utilizing chain drive or gear connection is used, then efficiency is improved, but no lubrication oil is conveyed when the second output shaft is shut down
Solution Approach 1:
The patent combines the advantages of both pump-less and electrically driven lubrication systems. The chain drive or gear connection provides continuous passive lubrication during normal operation, while an electrically driven pump is added as a supplemental device activated periodically to ensure adequate lubrication levels when the second output shaft is shut down. This hybrid approach merges the efficiency of passive systems with the reliability of active pumping.
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 maintains reliable lubrication of the transfer case components, reduces churning losses and unwanted moments of inertia, and enhances efficiency by ensuring sufficient lubrication without continuous oil flow, thereby prolonging the transfer case's operational life and improving fuel efficiency.
Implementation Method 1
an oil conveying device for conveying lubrication oil from the oil sump into a region disposed above the clutch or above the other component
Data Source
AI summary
A transfer case arrangement may include a first output shaft, a second output shaft, a clutch, a shutdown device, a lubrication device, and a control. The clutch may distribute a torque between the output shafts. The shutdown device may shut down the second output shaft when the clutch is disengaged. The lubrication device may lubricate the clutch and/or another component of the transfer case arrangement. The lubrication device may include an oil conveying device for conveying lubrication oil. The control may activate the oil conveying device periodically when the second output shaft is shut down.