Engineering machinery load port independent electrohydraulic load-sensitive energy regeneration hydraulic system
Technical field
The present invention relates to the hydraulic control system that electrohydraulic control technology is a feature, especially relate to a kind of engineering machinery load port independent electrohydraulic load-sensitive load compensation energy regeneration hydraulic system.
Background technique
In recent years, development along with electronic technology, measuring technology, hydraulic system has proposed more and more higher requirement to control performance and energy consumption control, engineering machinery adopts diesel engine-hydraulic system-multi executors drive scheme more, because its operating mode complexity, high-efficiency high-accuracy is taken into account the extensive concern that energy-conservation Control System Design has been subjected to industry.
At present be mainly reflected in following three aspects: improve operation element (diesel engine and hydraulic element) performance in the research aspect the engineering machinery control performance.Aspect operation element (comprising: diesel engine, oil hydraulic pump, control valve, oil hydraulic cylinder and oil hydraulic motor etc.), mainly be by improving structure and improving the control performance that processing technology improves element, but because technology comparative maturity, control performance improves effect not clearly.Adopt electric liquid guide control technique to improve the operability of system, but because engineering machinery operating mode complexity, existing engineering machinery is surmounting under the operating mode, is difficult to realize final controlling element speed controlling accurately.Adopt the system and the element of new function, the speed-regulating scheme of the electro-hydraulic proportional multi-way valve of breaking the normal procedure adopts the double spool technology, improves the control performance of system.
Hydraulic system energy-conservation aspect, energy-conservation technology such as load-sensitive, positive flow, minus flow control, permanent power control have all obtained application in the hydraulic shovel system, and have obtained certain energy-saving effect.But traditional control unit multi-way valve, since import and outlet interlock, the normal impedance load behavior, back of the body cavity pressure maintains than higher value, has reduced the energy-efficient performance of system, is surmounting under the load behavior, and the speed of final controlling element can not realize regeneration of energy control; And the lifting and transfer weight repeatedly of the power hydraulic cylinder in the engineering machinery, weight is transferred in the process, its inertia energy, gravitational potential energy and all be converted into the restriction loss of hydraulic system have not only caused the waste of the energy, also can cause harm such as heating, noise, vibration and reduction life-span.Hydraulic shovel with consumption maximum in the engineering machinery is an example, and the efficient of hydraulic system is approximately 13%~24% in the course of normal operation, and wherein, the efficient of control valve has only 40%.Generally speaking, the efficient that improves diesel engine, pump, oil hydraulic cylinder and motor is difficulty relatively, unless big breakthrough is arranged, otherwise single from the element energy-conservation space be not very big; And have bigger exploring potential ability aspect 60% the loss on control valve.
Summary of the invention
In order to reduce the restriction loss of hydraulic control valve, gravitational potential energy when making full use of the weight whereabouts, the inertia energy, the object of the present invention is to provide a kind of engineering machinery load port independent electrohydraulic load-sensitive load compensation energy regeneration hydraulic system, utilize pressure detecting element that system condition is carried out identification, divided working status is controlled, impedance is stretched out operating mode by reducing oil hydraulic cylinder back of the body cavity pressure, surmount and stretch out operating mode passing ratio throttle valve and pump and jointly control the regeneration that realizes gravitational potential energy, surmount the withdrawal operating mode and realize hydraulic cylinder speed control by spontaneous gravitational potential energy, the pressure and the flow of hydraulic system are maintained minimum, improve the control performance and the energy-efficient performance of system.
In order to achieve the above object, the present invention adopt technological scheme as follows:
Comprise Joystick, controller, proportional pressure control valve, variable displacement pump, two proportion directional valves, proportional throttle valve, three pressure transducers and oil hydraulic cylinder; Its interconnected relationship is as follows:
The oil outlet of variable displacement pump links to each other with filler opening, first pressure transducer, the filler opening of the first proportion directional valve and the filler opening of the second proportion directional valve of proportional pressure control valve respectively; The oil outlet of the first proportion directional valve links to each other with the filler opening of second pressure transducer, proportional throttle valve and the rodless cavity of oil hydraulic cylinder respectively; The oil outlet of the second proportion directional valve links to each other with the rod chamber of oil outlet, the 3rd pressure transducer and the oil hydraulic cylinder of proportional throttle valve respectively; Controller is electrically connected with Joystick, variable displacement pump, proportional pressure control valve, the first proportion directional valve, the second proportion directional valve, proportional throttle valve, first pressure transducer, second pressure transducer and the 3rd pressure transducer respectively.
Described controller is PC process control machine or programmable controller.
The present invention compares with background technique, has useful effect to be:
1, the working state of system's adopts pressure sensor detection system, divided working status is selected control strategy, under the prerequisite that realizes the accurate speed controlling of final controlling element, has reduced the throttling energy loss of system in the maximum magnitude, the regeneration of energy that has realized surmounting load;
2, pump control and valve control combine, and comprehensively its control advantage realizes speed controlling and Energy Saving Control accurately.
Description of drawings
Fig. 1 is the hydraulic system principle figure of load port independence control load sensitive energy regeneration.
Fig. 2 is the controller function module map.
Among the figure: 1, Joystick, 2, controller, 3, proportional pressure control valve, 4, variable displacement pump, 5, pressure transducer, 6, the proportion directional valve, 7, the proportion directional valve, 8, pressure transducer, 9, proportional throttle valve, 10, oil hydraulic cylinder, 11, pressure transducer.
Embodiment
Below in conjunction with accompanying drawing, provide details of the present invention by description to embodiment.
As shown in Figure 1, comprise Joystick 1, controller 2, proportional pressure control valve 3, variable displacement pump 4, two proportion directional valves 6,7, proportional throttle valve 9, three pressure transducers 5,8,11 and oil hydraulic cylinders 10; Its interconnected relationship is as follows:
The oil outlet of variable displacement pump 4 links to each other with filler opening, first pressure transducer 5, the filler opening of the first proportion directional valve 6 and the filler opening of the second proportion directional valve 7 of proportional pressure control valve 3 respectively; The oil outlet of the first proportion directional valve 6 links to each other with the filler opening of second pressure transducer 11, proportional throttle valve 9 and the rodless cavity of oil hydraulic cylinder 10 respectively; The oil outlet of the second proportion directional valve 7 links to each other with the rod chamber of oil outlet, the 3rd pressure transducer 8 and the oil hydraulic cylinder 10 of proportional throttle valve 9 respectively; Controller 2 is electrically connected with Joystick 1, variable displacement pump 4, proportional pressure control valve 3, the first proportion directional valve 6, the second proportion directional valve 7, proportional throttle valve 9, first pressure transducer 5, second pressure transducer 11 and the 3rd pressure transducer 8 respectively.
Described controller 2 is PC process control machine or programmable controller.
Working principle of the present invention is as follows:
As shown in Figure 2, Joystick 1 sends speed control signal, first pressure transducer, 5 detection variable pumps, 4 outlet pressure Ps, second pressure transducer 11 detects the pressure P 1 of oil hydraulic cylinder 10 rodless cavities, the 3rd pressure transducer 8 detects the pressure P 2 of oil hydraulic cylinder 10 rod chambers, the controller 2 load force F=p according to operating control signal that is received and definition
1A
1-P
2A
2Direction, the residing mode of operation of the system that determines: mode of operation 1, if control signal Vd is positive signal (hydraulic cylinder piston rod stretch out for just), load force also is positive signal (load hinders hydraulic cylinder piston and stretches out), being defined as impedance stretches out operating mode; Mode of operation 2, if control signal is a positive signal, load force is negative signal (load auxiliary hydraulic pressure cylinder piston rod stretches out), is defined as impedance and stretches out operating mode; Mode of operation 3, if control signal is negative signal (hydraulic cylinder piston rod withdrawal), load force is a positive signal, is defined as to surmount the withdrawal operating mode; Mode of operation 4, if control signal is a negative signal, load force is a negative signal, is defined as impedance withdrawal operating mode.Controller 2 is according to the residing mode of operation of system, respectively variable displacement pump 4 and proportional pressure control valve 3 are controlled the flow Qs and the variable displacement pump outlet pressure Ps of the output of Moderator Variable pump, and the first proportion directional valve 6, the second proportion directional valve 7 of difference control ratio throttle valve 9 and composition load port independent control unit, under the prerequisite of the accurate speed controlling that realizes hydraulic cylinder piston rod, reduce the energy loss of hydraulic system as far as possible.Concrete adjusting is as follows:
When controller 2 is in impedance and stretches out mode of operation 1 by program discrimination system, the first proportion directional valve 6 is used for controlling the speed of the stretching out V of hydraulic cylinder piston rod, control algorithm is the speed controlling strategy based on calculated flow rate feedback (estimating to carry out closed-loop speed control by the flow of the first proportion directional valve 6 by the pressure reduction and the spool travel that detect the first proportion directional valve two ends), the second proportion directional valve 7 forms the pressure closed loop feedback by the oil hydraulic cylinder 10 rod chamber pressure P 2 that the 3rd pressure transducer 8 detects, regulator solution cylinder pressure rodless cavity pressure makes it maintain low-pressure state, the value that proportional pressure control valve 3 Moderator Variable pump discharge pressure Ps make outlet pressure Ps only be higher than induced pressure is Δ Psmin, the value that variable displacement pump 4 makes flow system flow Qs exceed the required flow of speed controlling is Δ Qsmin, be used for the compensation variable pump and leak and a spot of spillway discharge of proportional pressure control valve, proportional throttle valve 9 is in the closed position.
When being in by program discrimination system, controller 2 surmounts when stretching out mode of operation 2, the first proportion directional valve 6 is used for controlling the speed of the stretching out V of hydraulic cylinder piston rod, its speed controlling strategy is the calculated flow rate feedback regulation, the second proportion directional valve 7 is in the closed position, proportional throttle valve 9 is used for regulator solution cylinder pressure 10 rodless cavity pressure P 1, makes it keep low pressure P
10Proportional pressure control valve 3 is used for controlled variable pump discharge pressure Ps, the value that makes the variable displacement pump outlet pressure exceed oil hydraulic cylinder 10 rodless cavity pressure P 1 is Δ Psmin, variable displacement pump 4 regulating system output flow Qs, the value of required flow Qx is Δ Qsmin when making flow system flow Qs exceed the control of oil hydraulic cylinder differential velocity, leaks and proportional pressure control valve trace spillway discharge in order to compensation.
When controller 2 was in impedance withdrawal mode of operation 3 by program discrimination system, the pressure P 1 of the first proportion directional valve, 6 control oil hydraulic cylinder rodless cavities made it maintain low voltage value P
10Its regulative mode adopts the pressure closed loop feedback control, the second proportion directional valve 7 is used to regulate the speed V of hydraulic cylinder piston rod, the calculated flow rate feedback strategy is adopted in speed regulation, proportional pressure control valve 3 is used for Moderator Variable pump discharge pressure Ps, and the value that makes its outlet pressure only be higher than induced pressure is Δ Psmin, variable displacement pump 4 regulating system flow Qs, make flow system flow exceed the required Δ Qsmin of hydraulic cylinder piston rod speed controlling, proportional throttle valve 9 is in the closed position.
When being in by program discrimination system, controller 2 surmounts withdrawal during mode of operation 4, the first proportion directional valve 6 is used to regulate the speed V of hydraulic cylinder piston rod, the speed regulation mode that adopts is the calculated flow rate feedback technique, the second proportion directional valve 7 is in the closed position, proportional throttle valve 9 is used for regulator solution cylinder pressure 10 rod chamber pressure P 2, makes it keep low pressure P
20, proportional pressure control valve 3 Moderator Variable pump discharge pressure Ps make its force value maintain Δ Psmin, and variable displacement pump 4 regulating system flow Qs make flow system flow maintain Δ Qsmin, guarantee the rapidity of its hydraulic cylinder piston rod.
Among Fig. 2, Up, Ur, U6, the corresponding respectively variable displacement pump 4 of U7, U9, proportional pressure control valve 3, the first proportion directional valve 6, second ratio are put the control input control signal to the valve 7 and first proportional throttle valve 9.