PTO Oil System Gravity Drain and Pressurized Clutch Circuit
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Solution Overview
Problem
Existing power take-off (PTO) systems suffer from spin losses and reduced efficiency due to limited lubricating oil return and lack of positive pressurized oil flow to the disconnect clutch, leading to inefficiencies during PTO component operation.
Innovation Solution
A PTO system with a lube oil drain return mechanism that utilizes gravity flow to return oil from the PTO housing to the transmission case, combined with a pressurized oil circuit that supplies continuous lubrication to the disconnect clutch through a controlled lube oil circuit and pressurized engagement line.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If lubricating oil fills the PTO housing to a predetermined level, then the rotating elements are adequately lubricated, but spin losses and reduced efficiency occur during PTO component operation and during periods when PTO components are not engaged
Solution Approach 1:
The patent segments the lubrication system into two distinct circuits: a pressurized engagement line that supplies oil only when the disconnect clutch is engaged, and a controlled lube oil circuit that continuously supplies oil to lubricate the friction plates. This segmentation allows lubrication to occur without continuous spin losses, as oil is supplied selectively rather than filling the entire PTO housing.
Solution Approach 2:
The patent employs a hydraulic pressurized engagement line that delivers pressurized oil directly to the disconnect clutch assembly only when engagement is required. This hydraulic system eliminates the need for continuous oil filling, reducing spin losses while maintaining adequate lubrication through controlled pressurized flow.
2Quantity of substance
If lubricating oil is supplied from the transmission lubrication system with limited return, then the PTO housing retains sufficient oil, but positive pressurized oil flow to the disconnect clutch is not provided
Solution Approach 1:
The patent divides the oil supply system into two separate circuits: a pressurized engagement line that provides high-pressure oil flow to the disconnect clutch, and a controlled lube oil circuit that provides continuous lubrication. This segmentation allows the system to maintain sufficient oil volume while delivering the required pressurized flow to the clutch assembly.
Solution Approach 2:
The patent introduces a PTO pump as an intermediary device that receives oil from the transmission lubrication system and conditions it for delivery through the pressurized engagement line and controlled lube oil circuit. This intermediary enables the system to maintain oil volume while providing the necessary pressurized flow to the disconnect clutch.
3Duration of action of stationary object
If the PTO housing retains lubricating oil, then continuous lubrication is available, but spin losses occur during periods when PTO components are not engaged
Solution Approach 1:
The patent implements periodic action through the controlled lube oil circuit that continuously supplies lubricating oil to the friction plates, while the pressurized engagement line operates only periodically when the disconnect clutch is engaged. This periodic pressurized supply eliminates spin losses during idle periods while maintaining continuous lubrication capability.
Solution Approach 2:
The patent ensures continuity of useful lubrication action through the controlled lube oil circuit that continuously supplies oil to the friction plates, while eliminating continuous spin losses by using periodic pressurized engagement line operation. The useful action of lubrication continues without the harmful effect of continuous spin.
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 solution reduces spin losses and enhances efficiency by ensuring effective lubrication and oil return, improving the operational performance of PTO components.
Implementation Method 1
The lube oil drain return receives oil that collects in the sump below the disconnect clutch assembly to be returned by gravity flow to the transmission case
Implementation Method 2
a pressurized engagement line selectively supplies a first portion of a pressurized oil volume to an apply piston thereby displacing the apply piston to engage a plurality of friction plates of the disconnect clutch assembly
Implementation Method 3
a controlled lube oil circuit isolated from the pressurized engagement line supplies a second portion of the pressurized oil volume directly to the friction plates and the disconnect clutch assembly to continuously lubricate the friction plates and the disconnect clutch assembly
Data Source
AI summary
A power take-off (PTO) system for a motor vehicle includes a PTO housing. The PTO housing is mounted to a transmission case. A disconnect clutch assembly is positioned within the PTO housing acting when supplied with a first volume of a pressurized oil from the transmission case to engage an output shaft member. A controlled lube oil circuit is isolated from the first volume of the pressurized oil. The controlled lube oil circuit supplies a second volume of the pressurized oil directly to the disconnect clutch assembly to lubricate the disconnect clutch assembly. A lube oil drain return is connected to the PTO housing. The lube oil drain return receives oil that collects inside the PTO housing to be returned to the transmission case.