Hydraulic Drive System Turning Control Valve Deceleration Energy
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Solution Overview
Problem
In hydraulic drive systems of construction machines, energy is unnecessarily consumed during gradual turning deceleration due to the immediate return of the turning control valve to its neutral position, causing the hydraulic oil to be blocked and applying a brake, even when no energy is required for the turning motor.
Innovation Solution
A hydraulic drive system with a variable displacement pump, turning control valve, supply/discharge lines, make-up lines with check valves, and a controller that adjusts the pump's discharge flow rate during deceleration, using a first and second regulation line to reduce energy consumption by ensuring sufficient hydraulic oil supply to the turning motor through make-up lines.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the turning control valve returns to neutral position immediately when turning is stopped, then the turning control is responsive and reliable, but the hydraulic oil is blocked and pressure increases immediately causing energy consumption
Solution Approach 1:
The patent introduces a bypass line with a bypass valve as an intermediary path for hydraulic oil during deceleration. This allows oil to flow from the high-pressure side to the low-pressure side through the bypass line, preventing pressure buildup while maintaining control valve responsiveness. The bypass valve acts as a mediator that releases pressure without affecting the neutral position return speed of the turning control valve.
2Ease of operation
If the discharge flow rate of the pump is adjusted to correspond to the inclination angle of the operating lever, then the hydraulic system responds accurately to operator input, but energy is consumed even when no turning energy is required
Solution Approach 1:
The patent implements dynamic adjustment of pump discharge flow rate based on the operational state. During deceleration, the controller reduces the pump's discharge flow rate below the level corresponding to the operating lever inclination angle. This dynamic adaptation allows the system to maintain responsiveness when needed while reducing energy consumption during deceleration phases when full flow is not required.
Solution Approach 2:
The system changes the discharge flow rate parameter of the pump based on operational phase. During deceleration, the controller adjusts the pump parameter to provide less flow than the operating lever position would normally dictate. This parameter change enables energy savings during deceleration while maintaining adequate flow for control purposes through the bypass mechanism.
3Force
If the opening area at the meter-out side of the turning control valve functions as a restrictor during gradual turning deceleration, then braking is applied, but the pump continues to discharge large flow rate consuming energy
Solution Approach 1:
The patent extracts the excess hydraulic flow from the main pump discharge path during deceleration. The controller reduces the pump's discharge flow rate to match the actual demand, separating the braking function (handled by the control valve restrictor) from the pump's flow generation. This extraction of unnecessary flow prevents energy waste while maintaining the braking effect through the control valve's meter-out restriction.
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 configuration reduces energy consumption during gradual turning deceleration by maintaining a low discharge flow rate and ensuring adequate hydraulic oil supply to the turning motor, thereby minimizing energy usage.
Implementation Method 1
a pair of make-up lines that connect the pair of supply/discharge lines to a tank, respectively, each make-up line being provided with a check valve that allows a flow from the tank to a corresponding one of the supply/discharge lines and blocks a reverse flow
Data Source
AI summary
A variable displacement pump supplies hydraulic oil to turning motor via a turning control valve; pair of supply/discharge lines connect turning motor and turning control valve; a pair of make-up lines connect pair of supply/discharge lines to tank, each line having check valve; turning operation device including operating lever and outputting operation signal corresponding to inclination angle of operating lever; a flow rate adjuster adjusts tilting angle of pump; and controller controls flow rate adjuster, such that tilting angle of pump increases in accordance with increase in operation signal outputted from turning operation device. Controller: turning acceleration and at time of constant speed turning, controls flow rate adjuster such that discharge flow rate of pump changes on first regulation line; turning deceleration, controls flow rate adjuster such that discharge flow rate of pump changes on second regulation line, second regulation line having slope less than slope of first regulation line.