High-Speed Clutch Lubrication Control for On-Demand Cooling
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Solution Overview
Problem
Existing transmission systems face challenges in efficiently delivering cooling fluid to clutch packs due to tight packaging, leading to inadequate heat dissipation during high-speed events, and prior art balance pistons do not provide for cooling fluid supply to the clutch pack.
Innovation Solution
A lubrication management system with a balance piston and cooling fluid shutoff pistons that control fluid flow to the clutch pack, using a controller to adjust pressure based on clutch temperature and engagement state, ensuring efficient cooling only when needed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If cooling fluid is continuously supplied to the clutch pack, then the clutch pack is cooled, but pump energy consumption increases and fluid distribution to other components is compromised
Solution Approach 1:
The system uses periodic action by controlling the cooling fluid supply to the clutch pack only during specific operational phases when heat generation occurs. The valve assembly selectively opens cooling passages during clutch engagement or high-speed events, and closes them during normal operation, thereby cooling the clutch pack when needed while minimizing pump energy consumption and preserving fluid for other components.
Solution Approach 2:
The clutch pack cooling system utilizes the existing kinetic energy and operational conditions of the clutch itself to trigger cooling. During high-speed events or engagement, the natural motion and pressure differentials activate the valve assembly to open cooling passages, allowing the clutch pack to self-regulate its cooling needs based on its operational state without requiring continuous external control.
2Temperature
If cooling fluid is supplied to the clutch pack during all operations, then the clutch pack is cooled, but fluid availability for other transmission components is reduced
Solution Approach 1:
The valve assembly implements periodic action by selectively opening cooling fluid passages only during clutch engagement or high-speed events. During normal operation, the passages remain closed, allowing cooling fluid to be distributed to other transmission components that require it, thereby optimizing fluid availability based on actual cooling needs.
Solution Approach 2:
The system applies local quality by providing cooling fluid directly to the clutch pack only when and where it is needed, rather than continuously throughout the transmission. The valve assembly creates localized cooling zones within the clutch pack during specific operational conditions, ensuring efficient heat dissipation while preserving fluid for other components during normal operation.
3Volume of moving object
If the transmission unit is tightly packaged, then space efficiency is improved, but delivering sufficient cooling fluid to the clutch pack interior becomes difficult
Solution Approach 1:
The cooling fluid passages are nested within the clutch pack structure itself, with passages formed through the clutch pack and valve assembly integrated into the existing clutch housing. This nested arrangement allows cooling fluid to be delivered directly to the interior of the clutch pack through passages that are contained within the compact clutch assembly, maintaining space efficiency while enabling sufficient cooling fluid flow.
Solution Approach 2:
The valve assembly acts as an intermediary mechanism that controls and directs cooling fluid flow to the clutch pack interior through strategically positioned passages. The valve assembly mediates between the main cooling fluid supply and the clutch pack, opening passages to allow fluid penetration into the clutch pack interior during engagement or high-speed events, thereby overcoming the packaging constraints.
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 system effectively cools the clutch pack during engagement, prolongs its lifespan, reduces pump energy consumption, and optimizes fluid distribution to other components, avoiding unnecessary cooling and resource wastage.
Implementation Method 1
Prior art transmission utilize a balance piston to provide a centrifugal balance to the clutch piston
Implementation Method 2
The controller is further configured to command the valve to open to allow fluid flow under a first pressure into the clutch piston cavity which engages the clutch piston with the clutch pack in a slip condition
Implementation Method 3
A clutch pack of a clutch assembly may generate a considerable amount of heat when utilized to clutch the transmission unit, particularly during periods of relative contacting rotation between the separator plates and the rapidly rotating friction disks as a result of friction
Implementation Method 4
It is thus desirable to dissipate heat by contacting the clutch pack with an active flow of liquid, such as a suitable lubricant
Data Source
AI summary
A lubricant management system is provided for a work vehicle transmission. The system includes a balance piston contained in a balance piston cavity configured to receive fluid under pressure and provided between a clutch piston and a balance piston; a cooling fluid shutoff piston mounted in a passageway of the clutch piston; a valve configured to control pressure of fluid flow into the clutch piston cavity; and a controller, having processing and memory architecture, operatively coupled to the valve and configured to command the valve to adjust the pressure of the fluid flowing into the clutch piston cavity during operation of the clutch assembly. The passageway has a lubrication supply opening that is closed by the cooling fluid shutoff piston when a first pressure is within the clutch piston cavity.