Background technology
The action of hydraulic crawler excavator is complicated, requires hydraulic system can guarantee Hydraulic Excavator's Boom, dipper and scraper bowl single movement separately, can make the realization composite move that cooperatively interacts between them again; Equipment action and turntable revolution can isolated operations, can realize the operating efficiency of composite move with the raising excavator again.Traditional hydraulic system; No matter be constant displacement pump or variable pump; Because the manipulating object and the operating mode of hydraulic crawler excavator are ever-changing, load and operating oil pressure that each equipment is suffered also have nothing in common with each other, therefore; The equipment that underload often occurs " is seized " phenomenon of the hydraulic fluid flow rate of heavy load equipment, causes composite move to be difficult to realize.For example, during the excavator walking,, make excavator can not realize straight line moving owing to the different skiddings of turning round that cause of left and right sides crawler belt load.Therefore, solve difference such as time load and the equipment that causes " is seized " the hydraulic oil problem, just solve the asynchronous assignment of traffic problem of load, seem particularly important.
Since the nineties in 20th century; On hydraulic crawler excavator, bring into use the load sensing controlled system; Generally be grouped into by variable pump, middle enclosed load sensing banked direction control valves, unloader, differential pressure pickup and electrical control division; No matter its control valve all has pressure-compensated valve in the meta open type or in meta enclosed mode.
But with the load sensing controlled system applies when the hydraulic crawler excavator; In order to guarantee its operate as normal; The pressure that pump is carried can only adapt with maximum load pressure; Be that load sensing controlled only works in the maximum load loop, also need adopt pressure compensation, so that valve port pressure reduction keeps definite value the loop that other load pressures are lower.When valve port is opened entirely, when the flow that work system requires surpassed the limit of oil pump feed ability, the executive component speed on the maximum load loop can be reduced to zero rapidly, thereby makes excavator lose the coordination ability of composite move.
Summary of the invention
In order to overcome the above-mentioned defective that prior art exists, the present invention provides a kind of can give the saturated dynamic allocation system of hydraulic crawler excavator flow of the different corresponding hydraulic fluid flow rates of load distribution according to the actual requirements.
Technical scheme of the present invention is: it comprises microcomputer, hydraulic pump, reversal valve, in-line, executing agency, hydrostatic sensor I, hydrostatic sensor II, oil return line, hydrostatic sensor III, hydrostatic sensor IV, displacement transducer I, displacement transducer II, and said microcomputer links to each other with hydrostatic sensor I, hydrostatic sensor II, hydrostatic sensor III, hydrostatic sensor IV, displacement transducer I, displacement transducer II through different signal lines respectively; Hydraulic pump is connected with reversal valve, and an end of said reversal valve links to each other with executing agency one end through oil return line; Executing agency's other end links to each other with the other end of reversal valve through in-line; Said hydrostatic sensor I, hydrostatic sensor II, displacement transducer I are one group, are located on the in-line; Said hydrostatic sensor III, hydrostatic sensor IV, displacement transducer II are another group, are located on the oil return line.
Preferred three the two logical reversal valves of said reversal valve.
Said executing agency can be shovel mechanism, slew gear, walking mechanism or ejector dozer mechanism etc.
The below of said hydraulic pump also is provided with screen pack, and the screen pack below is provided with hydraulic oil container.
The workflow of the present invention's the saturated dynamic allocation system of hydraulic crawler excavator flow is: (1) calculates the flow size that hydraulic pump is provided under current working; (2) judge whether hydraulic system is in the flow saturation state; (3) the required flow summation of each executing agency of computing system; (4) carry out assignment of traffic as requested; (5) sharing executing agency's assignment of traffic handles; (6) the spool flow-control is handled; (7) accomplishing flow dynamics distributes.
The present invention is simple in structure, compact, high efficiency, and long service life is convenient to maintenance, and is applied widely.Use the present invention, can overcome the shortcoming of common load sensing controlled system.When fuel feeding is not enough, make the operating rate of all executive components or supply flow rate change controlled by operator's intention, meet staff's operation requirement.
The specific embodiment
Below in conjunction with accompanying drawing and embodiment the present invention is described further.
With reference to Fig. 1; Present embodiment comprises microcomputer 1, hydraulic pump 2, reversal valve 3, in-line 7, executing agency 8, hydrostatic sensor I 4, hydrostatic sensor II 6, oil return line 9, hydrostatic sensor III 10, hydrostatic sensor IV 12, displacement transducer I 5, displacement transducer II 11, and said microcomputer 1 links to each other with hydrostatic sensor I 4, hydrostatic sensor II 6, hydrostatic sensor III 10, hydrostatic sensor IV 12, displacement transducer I 5, displacement transducer II 11 through different signal lines 13 respectively; Hydraulic pump 2 is connected with reversal valve 3, and reversal valve 3 is three two logical reversal valves, and reversal valve 3 one ends link to each other with executing agency 8 one ends through oil return line 9; Executing agency's 8 other ends link to each other with reversal valve 3 other ends through in-line 7; Hydrostatic sensor I 4, hydrostatic sensor II 6, displacement transducer I 5 are one group, are located on the in-line 7; Hydrostatic sensor III 10, hydrostatic sensor IV 12, displacement transducer II 11 are one group, are located on the oil return line 9.
Said executing agency 8 is shovel mechanism, slew gear, walking mechanism and ejector dozer mechanism etc.
Hydraulic pump 2 belows also are provided with screen pack, and the screen pack below is provided with hydraulic oil container.During work, screen pack one end stretches in the hydraulic oil of hydraulic oil container through oil circuit.Reversal valve 3 also stretches in the hydraulic oil of hydraulic oil container through oil circuit.
The method that use the present invention's the saturated dynamic allocation system of hydraulic crawler excavator flow is carried out the hydraulic fluid flow rate distribution is:
Execution in step 01, beginning;
Execution in step 02 is calculated the flow that provides under the hydraulic pump current working; The data such as products instruction that provided according to hydraulic pump production firm; Calculate the flow size (
) that hydraulic pump is provided under current working; The big young pathbreaker of this flow is used for subsequent calculations, to limit the flow through each executing agency.
Follow execution in step 03, the required flow summation of each executing agency of computing system:
N – actuating mechanism of excavating machine quantity;
Q
iThe required flow of each executing agency of – (L/min) derives from operator's input.
After the execution of step 03, execution in step 04 judges whether hydraulic system is in the flow saturation state: if not, promptly
, system is not in the flow saturation state, the size (Q of each operator of mechanism input flow rate instruction
i) also be the flow size (Q that each mechanism finally passes through
Si), change the processing of the 09th step over to, the spool flow is controlled processing; If yes, promptly hydraulic system is in the flow saturation state, and then execution in step 05, carries out priority class traffic and distributes:
A) each mechanism's traffic prioritization is confirmed
Confirming the preferential flow that guarantees first executing agency like the operator, also is Q
1Flow, if
, also be that the flow that hydraulic pump can provide just in time guarantees maybe can not guarantee Q
1When required flow is big or small, then have:
That is: the control flow of first executing agency is the flow
that pump can provide, and the control flow of all the other executing agencies is 0; Then, directly changeing step 6 handles;
Otherwise; If
is false; Also be that the flow that hydraulic pump provides has the executing agency of first priority except that satisfying; Also have unnecessary flow to supply other executing agency to use, then have:
At this moment, change next step b) handle;
B) whether has second, third processed
According to second, third priority situation that system is provided with, the flow of respective execution mechanisms is handled by the flow process in the above-mentioned steps 5.
After step 05 was finished, then execution in step 06 judged whether priority class traffic has assigned: if not, then return step 05, carry out priority class traffic and distribute; If yes, then execution in step 07, and the assignment of traffic with executing agency of shared assignment of traffic is handled:
If the priority executing agency that confirms has only one; All the other executing agencies are shares mechanism; Also be the 2nd ... N executing agency takes the flow sharing mode; After priority class traffic distributes, offer the flow of sharing mechanism and then be
;
The usual way that flow is shared is that constant speed descends, and also is that the velocity variations ratio of each executing agency is identical, and therefore, the actual instruction flow of sharing mechanism is:
Execution of step 07, execution in step 08, judge whether the calculated flow rate of each executing agency is accomplished:
If yes, then execution in step 09, and the spool flow of each displacement transducer is controlled processing:
can know from formula; Flow size and valve core opening (X) through spool; Pressure at both sides before and after the spool (P1, P2) relevant, pressure P 1, P2 etc. are determined by actuator load or system pressure size; Can not be used for carrying out control break; Therefore can only can be regarded as is independent variable, from following formula, when realizing that flow through spool satisfies required flow-control and requires; Can only realize that hence one can see that through constantly changing valve core opening (X):
X – valve core opening size, also promptly before and after spool pressure at both sides be respectively (P1, P2), when being Q through the flow size, pairing valve core opening position;
If, then do not return step 07;
Execution of step 09, execution in step 10, control each executing agency the flow size of corresponding spool; After dynamic assignment is handled in front, the big or small Q of each executing agency pairing spool control flow
Si, (P1i P2i), draws each valve core opening size Xi in conjunction with pressure at both sides detection case before and after each spool;
According to valve core opening control target Xi and the detected spool position Xci of valve core displacement sensor, draw control difference (Xi-Xci), the aperture position of controlling spool then moves to Xi, and this moment, the flow through valve was needed control flow size;
After the execution of step 10, execution in step 11 is accomplished flow dynamics and is distributed.