Charge Pressure Reduction Circuit for Loader Backhoe Transmission
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Solution Overview
Problem
Conventional loader backhoes and work vehicles maintain full transmission system pressure at all times, leading to inefficiency as transmission clutches are only active during specific operations and not continuously needed.
Innovation Solution
A device and method that reduce fluid pressures in the transmission circuit during periods of low or no demand using an electro-hydraulic directional control valve and vehicle controller to switch between high and low pressures based on operational modes, allowing pressure reduction when the transmission is not engaged.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If full system pressure is maintained at all times to power clutches, then clutch operation reliability is ensured, but energy consumption increases and transmission efficiency decreases during non-demand periods
Solution Approach 1:
The system dynamically adjusts pressure levels based on transmission demand. A directional control valve switches between a first pressure relief valve (providing full system pressure P1) and a second pressure relief valve (providing reduced pressure P2), allowing the system to transition between high-pressure and low-pressure states according to operational needs.
Solution Approach 2:
The invention changes the pressure parameter from a constant full system pressure to a variable pressure with two distinct levels. The system alternates between pressure level P1 (full system pressure) and P2 (reduced pressure), optimizing the balance between reliability and energy consumption based on real-time transmission demand.
2Reliability
If full system pressure is maintained continuously, then transmission component performance is ensured, but energy waste occurs during periods when transmission is not used
Solution Approach 1:
The system implements periodic pressure adjustment based on transmission usage patterns. The directional control valve periodically switches between maintaining full pressure (when transmission is needed) and reducing pressure (when transmission is not needed), creating a rhythmic pattern of high and low pressure states that eliminates continuous energy waste.
Solution Approach 2:
The system uses its own operational signals to control pressure levels. The vehicle controller monitors transmission demand and automatically activates the directional control valve to reduce pressure when the transmission is not required, allowing the system to self-regulate without external intervention.
3Reliability
If high fluid pressure is maintained at all times, then clutch activation reliability is ensured, but transmission efficiency decreases during non-operational periods
Solution Approach 1:
The pressure system becomes dynamic rather than static, automatically adapting to transmission demand. The directional control valve enables the system to switch between full pressure mode (ensuring clutch reliability) and reduced pressure mode (improving transmission efficiency), with the transition triggered by transmission operational status.
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 approach increases transmission efficiency by lowering fluid pressures during non-demand times, reducing energy consumption and prolonging component life by only maintaining high pressures when the transmission is actively engaged.
Implementation Method 1
an electro-hydraulic two way directional control valve having a closed position, an open position and a solenoid
Data Source
AI summary
A charge pressure reduction circuit for a loader backhoe in which a directional control valve causes the charge pump to operate at a system pressure high enough to adequately supply a clutch circuit when conditions indicate the vehicle is operating in a loader or transport mode. The directional control valve causes the charge pump to operate at a lower pressure as, for example, required for a lubrication circuit when conditions indicate the vehicle is in a backhoe operating mode.