CN204985136U - Unloading valve piece, switching core hydraulic system and engineering machinery - Google Patents

Unloading valve piece, switching core hydraulic system and engineering machinery Download PDF

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Publication number
CN204985136U
CN204985136U CN201520652489.0U CN201520652489U CN204985136U CN 204985136 U CN204985136 U CN 204985136U CN 201520652489 U CN201520652489 U CN 201520652489U CN 204985136 U CN204985136 U CN 204985136U
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China
Prior art keywords
valve
control
oil
opening
pump
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CN201520652489.0U
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Chinese (zh)
Inventor
谢朝阳
沈勇
任大明
张安民
马鹏鹏
赵梅
王苏东
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Technology Branch of XCMG Engineering Machinery Co Ltd
Science and Technology Branch of XCMG
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Technology Branch of XCMG Engineering Machinery Co Ltd
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Abstract

The utility model relates to an unloading valve piece, switching core hydraulic system and engineering machinery, the switching core hydraulic system include: constant delivery pump system, variable pump system, at least one execute component, at least one the 2nd execute component, switching core control valve block (9) and can be by unloading valve piece (17) of active control off -load, constant delivery pump system be an execute component fuel feeding, and unloading valve piece (17) set up between the fuel feeding oil circuit and oil return oil circuit in the constant delivery pump system, switching core control valve block (9) can realize the switching according to an execute component's load pressure (P3) on setting up the oil circuit between constant delivery pump system and variable pump system's fuel feeding oil circuit to make variable pump system be an execute component and the 2nd execute component fuel feeding simultaneously or be the 2nd execute component fuel feeding alone. The utility model discloses a switching core hydraulic system can decide nimble switching the between variable combination fuel feeding and the entire variable fuel feeding to the controllability of reinforcing hydraulic system fuel feeding.

Description

A kind of unloading valve block, opening and closing core hydraulic system and engineering machinery
Technical field
The utility model relates to construction machinery hydraulic system technical field, particularly relates to a kind of unloading valve block, opening and closing core hydraulic system and engineering machinery.
Background technique
Widely, different purposes and complicated operating mode determine the complexity of its hydraulic work system to engineering machinery purposes.Construction machinery hydraulic system common at present has quantitative system, quantitative and set of variables assembly system and entire variable system etc., and quantitative system cost is lower, but energy loss is large; Entire variable energy saving of system successful, but cost is higher, is unfavorable for popularity; Quantitative and set of variables assembly system carries out Variable Control to steering system, and cost increases little, its energy-saving effect relatively, and quantitative and set of variables assembly system has very high cost performance, thus is widely used in engineering reality.
Quantitative and the set of variables assembly system in prior art, engineering machinery adopted is generally structure described below, metering pump provides hydraulic oil for operation element, variable displacement pump provides hydraulic oil for steering component, and oil feeding line is provided with pressure-gradient control valve, unilaterally connected is realized by one-way valve and multi-way valve between variable displacement pump and the oil feeding line of metering pump, when multi-way valve is connected by control that is automatically controlled or hydraulic control signal, namely variable displacement pump can be operation element part fuel feeding.In addition, variable displacement pump and metering pump all can carry out off-load when fuel feeding fluid exceedes loading demand by unloading valve.
Its working principle is: (1), when the work of only steering component, variable displacement pump can flow fuel feeding according to demand, without spill losses, and the off-load of metering pump meta; (2) when only operation element manipulation, if metering pump supply flow is not enough, then variable displacement pump provides corresponding flow, without spill losses according to work requirements; If metering pump supply flow is sufficient, then variable displacement pump carries out small displacement Low-pressure load discharge; (3) when steering component and operation element work simultaneously, variable displacement pump is preferably steering component fuel feeding.
Known by carrying out analysis to the quantitative of prior art and set of variables assembly system, when the load of operation element is larger, variable displacement pump plays the effect of assisted quantitative oil pump feed, once the flow that metering pump or variable displacement pump provide is higher than requirements, just can carry out passive off-load.If but need to regulate fuel delivery reposefully in real time under the operating mode that load is larger, just cannot accomplish to make variable displacement pump replace metering pump to be embodied as separately whole system fuel feeding completely, this restriction causes the selection of hydraulic system fuel system not too flexible, and controllability is poor.
Model utility content
First object of the present utility model proposes a kind of unloading valve block, can control unloading valve block as required and carry out off-load, thus strengthen the controllability of off-load action.
Second object of the present utility model proposes a kind of opening and closing core hydraulic system and engineering machinery, opening and closing core hydraulic system can be made to determine to switch flexibly between variable combination fuel feeding and entire variable fuel feeding, thus strengthen the controllability of hydraulic system fuel feeding.
For achieving the above object, the utility model first aspect provides a kind of unloading valve block, for being arranged between the oil feeding line of hydraulic system and oil return circuit, comprise: the mode of operation of the first valve body, unloading valve 22 and external control switches on-off valve 19, the filler opening of described unloading valve 22 is communicated with oil return inlet T 5 with the oil inlet P 5 of described first valve body respectively with oil outlet, switches on-off valve 19 turn on and off between the control port of described unloading valve 22 and described oil return inlet T 5 by described mode of operation.
Further, described unloading valve 22 is cartridge valve, described cartridge valve is provided with the first filler opening 22A, the first oil outlet 22B and the first control port 22C, described first filler opening 22A is communicated with oil return inlet T 5 with the oil inlet P 5 of described first valve body respectively with described first oil outlet 22B, the oil circuit that described first control port 22C is communicated with the oil inlet P 5 of described first valve body is provided with first segment discharge orifice 23, and described mode of operation switches on-off valve 19 and is arranged on the oil circuit between described first control port 22C and the oil return inlet T 5 of described first valve body.
Further, also comprise relief valve 25, on the oil circuit between the oil return inlet T 5 that described relief valve 25 is arranged on described first segment discharge orifice 23 and described first valve body.
Further, described first valve body is provided with load feedback hydraulic fluid port P6, and described load feedback hydraulic fluid port P6 is communicated with the control chamber without spring side of described relief valve 25.
Further, the oil return inlet T 5 of described first valve body is communicated with the control chamber of the spring side of described relief valve 25.
Further, be communicated with the first one-way valve 21 by the variable orifice 20 be arranged in parallel between the oil inlet P 5 of described first valve body and the first filler opening 22A of described cartridge valve.
Further, the second section discharge orifice 27 at the first control port 22C place being arranged on described cartridge valve is also comprised.
Further, also comprise be arranged on described first valve body the oil circuit between oil inlet P 5 and load feedback hydraulic fluid port P6 on the second one-way valve 24, the oil inlet P 5 of described first valve body is by described second one-way valve 24 and described load feedback hydraulic fluid port P6 unilaterally connected.
For achieving the above object, the utility model second aspect provides a kind of opening and closing core hydraulic system, comprise: Constant Pump System, variable pump systems, at least one first executive component, at least one second executive component, opening and closing core control valve block 9 and the unloading valve block 17 described in above-described embodiment
Described Constant Pump System is described first executive component fuel feeding, and described unloading valve block 17 is arranged between oil feeding line in described Constant Pump System and oil return circuit;
On oil circuit between the oil feeding line that described opening and closing core control valve block 9 is arranged on described Constant Pump System and described variable pump systems, opening and closing can be realized, to make described variable pump systems simultaneously for described first executive component and the second executive component fuel feeding or separately for described second executive component fuel feeding according to the induced pressure P3 of described first executive component.
Further, also comprise mode of operation diverter switch 26, it is electromagnetic switch valve that described mode of operation switches on-off valve 19, and the control end of described electromagnetic switch valve is connected with described mode of operation diverter switch 26.
Further, the oil return circuit of described Constant Pump System is provided with radiator 16 and oil return filter cleaner 15, and the oil return inlet T 5 of described unloading valve block 17 is connected on the oil circuit between described radiator 16 and described oil return filter cleaner 15.
Further, described opening and closing core control valve block 9 is hydraulic control proportional control valve, and the openings of sizes of described opening and closing core control valve block 9 can be adjusted by the induced pressure P3 of described first executive component.
Further, mode of operation switches on-off valve 19 and when described first actuator movement is to the predeterminated position of its travel end, can control the initiatively off-load of described unloading valve 22.
Further, also comprise pilot control block 10, described pilot control block 10 is arranged on the oil feeding line in described variable pump systems, and the action that can be respectively described first executive component and described second executive component provides control fluid.
Further, described pilot control block 10 comprises: the second valve body, reduction valve 31 and solenoid directional control valve 32, the oil inlet P 7 of described second valve body is communicated with the oil feeding line of described variable pump systems, and the first oil outlet XS of described second valve body is connected with the oil circuit control of described Constant Pump System and described variable pump systems respectively with the second oil outlet XZ;
Described reduction valve 31 is arranged between the oil inlet P 7 of described second valve body and the second oil outlet XZ of described second valve body, described solenoid directional control valve 32 is arranged between the oil outlet of described reduction valve 31 and the first oil outlet XS of described second valve body, can control the break-make of described pilot control block 10 to the oil circuit control fuel feeding of described Constant Pump System.
Further, described pilot control block 10 also comprises accumulator 33, and described accumulator 33 is arranged on the oil circuit between described reduction valve 31 and described solenoid directional control valve 32.
Further, also comprise pilot-actuated valve block 28, described pilot-actuated valve block 28 is for screening load pressure signal larger in described first executive component and described second executive component, and feed back to the variable control mechanism of the variable displacement pump 2 in described variable pump systems as load feedback signal, and then control the oil pump capacity of described variable displacement pump 2.
Further, described pilot-actuated valve block 28 comprises shuttle valve and the 3rd throttle orifice 30, two filler openings of described shuttle valve are respectively used to the load pressure signal receiving described first executive component and described second executive component, the oil outlet of described shuttle valve is provided with described 3rd throttle orifice 30, is screened larger load pressure signal in described first executive component and described second executive component by described shuttle valve.
Further, also comprise constant difference overflow valve 29, between the oil feeding line that described constant difference overflow valve 29 is arranged on described variable pump systems and oil return circuit, the spring chamber of described constant difference overflow valve 29 is communicated with the oil outlet of described pilot-actuated valve block 28.
Further, described first executive component is Job execution element, and described second executive component is non-Job execution element.
For achieving the above object, the utility model third aspect provides a kind of engineering machinery, comprises the opening and closing core hydraulic system described in above-described embodiment.
Further, described engineering machinery is loader, and described first executive component comprises tipping bucket cylinder 12 and swing arm cylinder 13, and described second executive component comprises left steering cylinder 7 and right steering cylinder 8.
Further, described Constant Pump System comprises metering pump 18, pilot valve 14 and distributing valve 11, described distributing valve 11 is arranged on the oil feeding line of described metering pump 18, described pilot valve 14 can provide control signal for described distributing valve 11, thus controls one of the two in described tipping bucket cylinder 12 and described swing arm cylinder 13 execution expanding-contracting action.
Further, described variable pump systems comprises: variable displacement pump 2, flux amplification valve 6 and commutator 3, described flux amplification valve 6 is arranged on the oil feeding line of described variable displacement pump 2, described commutator 3 can provide control signal for described flux amplification valve 6, thus controls described left steering cylinder 7 and described right steering cylinder 8 performs expanding-contracting action.
Based on technique scheme, the opening and closing core hydraulic system of the utility model embodiment, by arranging unloading valve block between the oil feeding line and oil return circuit of Constant Pump System, and the mode of operation being provided with external control in this unloading valve block switches on-off valve, unloading valve can be controlled and whether open initiatively off-load pattern, thus opening and closing core hydraulic system can be made to determine to switch flexibly between variable combination fuel feeding and entire variable fuel feeding, enhance controllability and the flexibility of hydraulic system fuel feeding, suitable fuel system can be chosen like this according to the different operating modes of hydraulic system, to improve hydraulic system further to the control performance of executive component.
Accompanying drawing explanation
Accompanying drawing described herein is used to provide further understanding of the present utility model, and form a application's part, schematic description and description of the present utility model, for explaining the utility model, is not formed improper restriction of the present utility model.In the accompanying drawings:
Fig. 1 is the hydraulic schematic diagram of an embodiment of the utility model unloading valve block;
Fig. 2 is the hydraulic schematic diagram of another embodiment of the utility model unloading valve block;
Fig. 3 is the hydraulic schematic diagram of another embodiment of the utility model unloading valve block;
Fig. 4 is the hydraulic schematic diagram of an embodiment of the utility model opening and closing core hydraulic system;
Fig. 5 is the hydraulic schematic diagram of another embodiment of the utility model opening and closing core hydraulic system;
Fig. 6 is the hydraulic schematic diagram of a specific embodiment for loader of the utility model opening and closing core hydraulic system;
Fig. 7 is the system unloaded pressure characteristic of another embodiment of the utility model opening and closing core hydraulic system.
Description of reference numerals
1-hydraulic oil container; 2-variable displacement pump; 3-commutator; 4-right limit valve; 5-left limit valve; 6-flux amplification valve; 7-left-hand rotation cylinder; 8-right steering cylinder; 9-opening and closing core control valve block; 10-pilot control block; 11-distributing valve; 12-tipping bucket cylinder; 13-swing arm cylinder; 14-pilot valve; 15-oil return filter cleaner; 16-radiator; 17-unloading valve block; 18-metering pump; 19-mode of operation switching solenoid valve; 20-variable orifice; 21-first one-way valve; 22-unloading valve; 23-first segment discharge orifice; 24-second one-way valve; 25-relief valve; 26-mode of operation diverter switch; 27-second section discharge orifice; 28-pilot-actuated valve block; 29-constant difference overflow valve; 30-the 3rd throttle orifice; 31-reduction valve; 32-solenoid directional control valve; 33-accumulator; 22A-first filler opening; 22B-first oil outlet; 22C-first control port; 61-hydraulic control proportional reversing valve; 62-pressure-gradient control valve.
Embodiment
Below describe the utility model in detail.In the following paragraphs, the different aspect of embodiment is defined in more detail.The each side of restriction like this can combine with any other one aspect or many aspects, not may be combined with unless explicitly stated otherwise.Especially, be considered to preferred or favourable any feature and one or morely can be considered to preferred or favourable feature with other.
Terms such as " first ", " second " that occur in the utility model is only for convenience of description, to distinguish the different constituent elementss with same names, does not represent successively or primary-slave relation.
First, the utility model provides a kind of unloading valve block, hydraulic schematic diagram as shown in FIG. 1 to 3, for being arranged between the oil feeding line of hydraulic system and oil return circuit, comprise: the mode of operation of the first valve body, unloading valve 22 and external control switches on-off valve 19, the filler opening of unloading valve 22 is communicated with oil return inlet T 5 with the oil inlet P 5 of the first valve body respectively with oil outlet, switches on-off valve 19 turn on and off between the control port of unloading valve 22 and oil return inlet T 5 by mode of operation.
The unloading valve block of this embodiment can be arranged in metering pump or variable pump systems, according to the demand of different operating mode, mode of operation can be controlled neatly by external control signal and switch turning on and off of on-off valve, whether off-load is carried out to control unloading valve, thus the controllability enhanced when oil hydraulic pump carries out off-load, and then adapt to the different demands of hydraulic system neatly.
In a specific embodiment, as shown in Figure 1, the unloading valve 22 mentioned in above-described embodiment is cartridge valve, be suitable for oil hydraulic pump and need the flow of off-load and the larger occasion of pressure, and installation in the first valve body also more for convenience, this cartridge valve is provided with the first filler opening 22A, first oil outlet 22B and the first control port 22C (being located on spring chamber), first filler opening 22A is communicated with oil return inlet T 5 with the oil inlet P 5 of the first valve body respectively with the first oil outlet 22B, the oil circuit that first control port 22C is communicated with the oil inlet P 5 of the first valve body is provided with first segment discharge orifice 23, mode of operation switches on-off valve 19 and is arranged on the oil circuit between the first control port 22C and the oil return inlet T 5 of the first valve body.The unloading valve block of this embodiment is when mode of operation switching on-off valve 19 is in on-state, hydraulic oil can produce pressure reduction at spool two ends when flowing through first segment discharge orifice 23, make the pressure of pressure higher than the first control port 22C of cartridge valve first filler opening 22A, thus make spool against the force of the spring move and open, and then make the hydraulic oil flowing through oil inlet P 5 flow back to hydraulic oil container 1 (see Fig. 4) from oil return inlet T 5, at this moment unloading valve block 17 has the initiative off-load pattern.
In another embodiment, as shown in Figure 2, unloading valve block of the present utility model also comprises relief valve 25, and relief valve 25 is arranged on the oil circuit between first segment discharge orifice 23 and the oil return inlet T 5 of the first valve body.When mode of operation switching on-off valve 19 is in the state of shutoff, hydraulic oil can not pass through first segment discharge orifice 23, unloading valve 22 can not be opened, when the pressure (oil inlet P 5 of the first valve body) of the oil feeding line of hydraulic system exceedes predefined value, the pressure against the force of the spring of the control port of relief valve 25, relief valve 25 is connected, and unnecessary hydraulic oil can pass through relief valve 25 hydraulic return fuel tank 1, and at this moment unloading valve block 17 is in passive off-load pattern.
More preferably, the first valve body is provided with load feedback hydraulic fluid port P6, and load feedback hydraulic fluid port P6 is communicated with the control chamber without spring side of relief valve 25.Preferably, control chamber in control chamber in this embodiment and a upper embodiment independently can be arranged at the offside of spring chamber, when the pressure of load feedback hydraulic fluid port P6 is larger, relief valve 25 can be connected by it, when mode of operation switching on-off valve 19 is in shutdown mode, the unnecessary fluid that oil hydraulic pump provides is by relief valve 25 hydraulic return fuel tank 1; When mode of operation switching on-off valve 19 is in connection pattern, the hydraulic oil entered from the oil inlet P 5 of the first valve body has small part to flow away from the relief valve 25 connected, thus flow through the spool two ends generation pressure reduction that first segment discharge orifice 23 makes unloading valve 22, and then unloading valve 22 is opened, make most of fluid carry out active off-load by unloading valve 22.
In the hydraulic system of reality, in order to prevent the spring chamber enclosure portion fluid of relief valve 25, causing spool normally cannot move commutation, preferably, the control chamber of the oil return inlet T 5 of the first valve body with the spring side of relief valve 25 being communicated with.
In order to make oil hydraulic pump more steady when off-load, larger impact can not be caused to system, and the angle in the working life from raising unloading valve block 17, those skilled in the art can design throttle element and one-way valve element by the correct position in unloading valve block 17, will provide several optional embodiment below.
In one embodiment, as shown in Figure 3, be communicated with the first one-way valve 21 by the variable orifice 20 be arranged in parallel between the oil inlet P 5 of the first valve body and the first filler opening 22A of cartridge valve.When setting value lower than relief valve 25 of the pressure of load feedback hydraulic fluid port P6, relief valve 25 cuts out, flow through the flow vanishing of first segment discharge orifice 23, the pressure difference at cartridge valve two ends reduces to zero, the spool of cartridge valve resets under spring force, now due to the effect of variable orifice 20, makes the reset speed of spool controlled, thus avoid spool to the shock of valve seat, and spool quick closedown and the compression shock caused.Because the fluid returned from the first filler opening 22A when spool returns may bring compression shock to hydraulic pump outlet, thus need the latus rectum size regulating variable orifice 20 according to the actual characteristic of hydraulic system.Due between the oil inlet P 5 of the first valve body and the first filler opening 22A of cartridge valve by the first one-way valve 21 unilaterally connected, thus when spool is opened, can not through variable orifice 20 when hydraulic oil enters cartridge valve.
In another kind of embodiment, this unloading valve block 17 also comprises the second section discharge orifice 27 at the first control port 22C place being arranged on cartridge valve, second section discharge orifice 27 can make cartridge valve in the process of opening, slow down the opening speed of spool, prevent spool from clashing into valve seat, thus reduce to impact, make unloading process comparatively stable, and extend the working life of spool and valve seat.
By arranging second section discharge orifice 27 and variable orifice 20 in unloading valve block 17, if oil cylinder internal pressure in lifting process exceedes setting pressure, carry out off-load, because the first control port 22C place at unloading valve 22 is provided with second section discharge orifice 27, then spool opening speed is slower, simultaneous quantitative pump 2 is also in repairing, the hydraulic fluid flow rate then entering oil cylinder can not reduce suddenly, and unloading valve 22 thus can not be caused to close suddenly; When oil cylinder internal pressure be reduced to need turn off unloading valve 22 time, because the first filler opening 22A place at unloading valve 22 is provided with variable orifice 20, then spool closing velocity is comparatively slow, will still make oil cylinder internal pressure instantaneous again higher than setting value when fuel feeding in outside.Thus the hydraulic system that have employed this unloading valve block has stable unloading function, unloading valve block 17 will be caused frequently to open and close because of system pressure fluctuation, thus eliminate system vibration and impact, extend the working life of each element and system.If unloading valve does not have one-way throttle to cushion when opening and closing, then spool keying speed is very fast, because in lifting process, oil cylinder internal pressure increases gradually, once exceed setting pressure, carry out off-load, in off-load moment, the flow entering oil cylinder reduces suddenly, oil cylinder working-pressure is caused to reduce suddenly, this pressure again can lower than the pressure of unloading valve setting, then unloading valve cuts out again immediately, close after oil cylinder pressure again can higher than set up pressure unloading, so start off-load again, appearance like this repeatedly high frequency opens and closes, and causes noise and impact.
Further, this unloading valve block 17 also comprise be arranged on the first valve body the oil circuit between oil inlet P 5 and load feedback hydraulic fluid port P6 on the oil inlet P 5 of the second one-way valve 24, first valve body by the second one-way valve 24 and load feedback hydraulic fluid port P6 unilaterally connected.Wherein, the low pressure oil of the high pressure oil of load feedback hydraulic fluid port P6 and oil inlet P 5 can be kept apart by the second one-way valve 24, and when making the pressure of load feedback hydraulic fluid port P6 larger, oil hydraulic pump cannot carry out fuel feeding, thus protection oil hydraulic pump.Such as in the hydraulic system shown in Fig. 4, unloading valve block 17 is arranged in Constant Pump System, and thus the second one-way valve 24 can protect metering pump 18.In the embodiment not arranging the second one-way valve 24, unloading valve block as depicted in figs. 1 and 2, the oil inlet P 5 of the first valve body is consistent with the pressure of load feedback hydraulic fluid port P6.
Secondly, the utility model additionally provides a kind of opening and closing core hydraulic system, as shown in Figure 4, comprise: the unloading valve block 17 of Constant Pump System, variable pump systems, at least one first executive component, at least one second executive component, opening and closing core control valve block 9 and the various embodiments described above, Constant Pump System is the first executive component fuel feeding, and unloading valve block 17 is arranged between oil feeding line in Constant Pump System and oil return circuit, opening and closing core control valve block 9 is arranged on the oil circuit between Constant Pump System and the oil feeding line of variable pump systems, opening and closing can be realized according to the induced pressure P3 of the first executive component, be the first executive component and the second executive component fuel feeding to make variable pump systems simultaneously or be separately the second executive component fuel feeding, this opening and closing core hydraulic system adopts the induced pressure P3 of the first executive component to feed back, control the open and close of opening and closing core control valve block 9, control signal is chosen fairly simple, without the need to through Mutiple Choice with compare, thus simplify system, also make control more reliable.
Wherein, Constant Pump System comprises: metering pump 18, all kinds of control valve, safety valve and connection oil circuit etc., variable pump systems comprises: variable displacement pump 2, all kinds of control valve, safety valve and connection oil circuit etc., in order to be clearly shown that the annexation of each critical piece in the diagram, the parts such as control valve are omitted, only provides the schematic diagram of principle.
Preferably, in engineering machinery, first executive component can correspond to work executive component, for the various operation actions of performance of work machinery, such as in loader, as shown in Figure 6, work executive component can be tipping bucket cylinder 12 and swing arm cylinder 13, controls the action of scraper bowl and the lifting of swing arm respectively; Second executive component corresponds to inoperative executive component, for the go to action of performance of work machinery.Wherein, the first executive component and the second executive component can be oil hydraulic cylinder or motor etc.
Further, this opening and closing core hydraulic system also comprises mode of operation diverter switch 26, and mode of operation switching on-off valve 19 is electromagnetic switch valve, and the control end of electromagnetic switch valve is connected with mode of operation diverter switch 26.
Opening and closing core hydraulic system of the present utility model, oil circuit between Constant Pump System and the oil feeding line of variable pump systems is provided with opening and closing core control valve block 9, different fuel feeding patterns can be selected according to the loading condition in hydraulic system, such as: (1) is when engineering machinery is at straight line moving, due to work executive component and the equal attonity of inoperative executive component, variable displacement pump 2 is standby, the off-load of metering pump 18 meta, and opening and closing core control valve block 9 is in and closes wick-like state; (2) when inoperative executive component single movement, the induced pressure P3 that work executive component is corresponding is very little, and be not enough to open opening and closing core control valve block 9, to reduce the energy loss of variable displacement pump 2, energy saving of system effect is comparatively obvious; (3) when work executive component single movement, fuel feeding is carried out by metering pump 18; (4) when work executive component and the action simultaneously of inoperative executive component, the induced pressure P3 that work executive component is corresponding increases gradually, when cracking pressure higher than opening and closing core control valve block 9, the flow of variable displacement pump 2 becomes large gradually, collaborates fuel feeding with metering pump 18.
Because this opening and closing core hydraulic system is provided with the unloading valve block 17 of previous embodiment between the oil feeding line and oil return circuit of Constant Pump System, turning on and off of on-off valve 19 is switched because this kind of unloading valve block 17 can control mode of operation neatly by external control signal, whether off-load is carried out to control unloading valve 22, thus opening and closing core hydraulic system can be made to determine to switch flexibly between variable combination fuel feeding and entire variable fuel feeding, thus strengthen controllability and the flexibility of hydraulic system fuel feeding, suitable fuel system can be chosen according to the different operating modes of hydraulic system.To improve hydraulic system further to the control performance of executive component.That is, on the basis of the four kinds of fuel feeding patterns analyzed above, a kind of new fuel feeding pattern can be increased again, that is: when the executive component that works is in low-speed heave-load operating mode, mode of operation diverter switch 26 can be opened, mode of operation switching solenoid valve 19 is obtained electric, unloading valve block 17 so just can be made to be in pressure unloading condition, whole hydraulic system switches to entire variable system, now, the movement speed of each executive component can be slack-off, but have good maneuverability and micro-control, and energy-saving effect is comparatively quantitative and set of variables assembly system is more obvious.Such as, in loader, this fuel feeding pattern is particularly suitable for low speed super-heavy load shovel dress operating mode, and under this entire variable fuel feeding pattern, complete machine has good expansion, can realize good control performance by other attached facility supporting.
In another embodiment of the present utility model, as shown in Figure 6, the oil return circuit of Constant Pump System is provided with radiator 16 and oil return filter cleaner 15, and the oil return inlet T 5 of unloading valve block 17 is connected on the oil circuit between radiator 16 and oil return filter cleaner 15.This Connecting format mainly forms pressure reduction compared with the hydraulic oil of large discharge at radiator 16 place in off-load moment to prevent, thus impact radiator 16, and then damage is caused to radiator 16.
In the above-described embodiment, opening and closing core control valve block 9 is hydraulic control proportional control valve, the openings of sizes of opening and closing core control valve block 9 can be adjusted by the induced pressure P3 of the first executive component, to carry out the size of Moderator Variable pump 2 to its fuel delivery according to the load of work executive component, the mode of this dynamic conditioning can meet the demand of hydraulic work system, plays energy-conservation effect again.
If work executive component performs lifting action; buffering and protective measure can also be taked at lifting process end; herein still to be applied as example to illustrate in loader; by adjusting the preset pressure of relief valve 25; when the gross weight that user shovels dress material exceedes setting value; a bit of stroke L0 is reserved at the end of boom cylinder 13 lifting stroke; such as can by arranging displacement transducer to realize the detection of stroke L0; in this L0 stroke; control mode of operation switching on-off valve 19 by mode of operation diverter switch 26 to connect, to guarantee that unloading valve 22 is opened.Therefore, at the end of lifting stroke, only have variable displacement pump 2 fuel feeding, lifting speed can be reduced like this, the compression shock of boom cylinder 13 inside when reducing to give rise to top, thus make the work more steadily safety of complete machine.The pressure unloading curve of this embodiment's opening and closing core hydraulic system as shown in Figure 7, when boom cylinder 13 rises to L0 place, off-load forced by metering pump 18, suddenly there is flex point in its pressure diagram P5, the pressure that metering pump 18 exports directly is down to 7.6bar from 189.9bar, whole system switches to only by variable displacement pump 2 fuel feeding, thus its pressure diagram P1 entirety is in the trend continuing to rise, variable displacement pump 2 to regulate self stroking mechanism in real time according to the size of load, thus realize the adjustment of fuel delivery size, finally after whole system quits work, variable displacement pump 2 just stops output hydraulic pressure oil.
As a rule, hydraulic system can provide pilot control fluid by arranging the guide's oil pump arranged separately, and hydraulic system of the present utility model is in order to simplify system as far as possible, as shown in Figure 5 and Figure 6, oil feeding line in variable pump systems is provided with pilot control block 10, the action that can be respectively work executive component and inoperative executive component provides control fluid.This embodiment can cancel guide's oil pump in original system and relief valve, can simplify system, and eliminate the energy loss of relief valve.Conveniently understand, also some parts in hydraulic system are omitted in Fig. 5, just schematically illustrate the annexation of each critical piece.
Particularly, pilot control block 10 comprises: the second valve body, reduction valve 31 and solenoid directional control valve 32, the oil inlet P 7 of the second valve body is communicated with the oil feeding line of variable pump systems, first oil outlet XS of the second valve body is connected with the oil circuit control of Constant Pump System and variable pump systems respectively with the second oil outlet XZ, is namely connected with the first executive component controlling component in Fig. 5 and the second executive component controlling component respectively.Wherein, reduction valve 31 is arranged between the oil inlet P 7 of the second valve body and the second oil outlet XZ of the second valve body, solenoid directional control valve 32 is arranged between the oil outlet of reduction valve 31 and the first oil outlet XS of the second valve body, can control the break-make of the oil circuit control fuel feeding of pilot control block 10 pairs of Constant Pump System.When solenoid directional control valve 32 obtains electric, first oil outlet XS has guide's fluid to export, complete machine can perform an action, once complete machine power-off or stopping are powered to solenoid directional control valve 32, complete machine action is immediately by locking, thus prevent misoperation, and then improve the Security of complete machine, thus solenoid directional control valve 32 plays the effect that electric controlled safety lock stops.When not needing to turn to, reduction valve 31 not output flow, has certain energy-saving effect.
Further, pilot control block 10 also comprises accumulator 33, accumulator 33 is arranged on the oil circuit between reduction valve 31 and solenoid directional control valve 32, when the hydraulic oil that variable displacement pump 2 provides is comparatively sufficient, the unnecessary hydraulic oil of part is stored in accumulator 33, when the hydraulic oil that variable displacement pump 2 provides is not enough to provide guide's fluid, then the hydraulic oil be previously stored in accumulator 33 starts release, to reach the object of repairing.Between reduction valve 31 and accumulator 33, be also provided with one-way valve, prevent the fluid reverse flow in accumulator 33.In addition, except arranging oil inlet P 7 on the second valve body, another one oil inlet P 2 can also be set, be used for connecting emergent guide's oil pump, when variable displacement pump 2 and accumulator 33 normally can not provide guide's fluid, emergent guide's oil pump can also ensure system worked well.Can arrange shuttle valve between oil inlet P 7 and P2, in both being used for screening, the larger hydraulic fluid port of pressure is pilot control block 10 fuel feeding, and two filler opening places of shuttle valve also can arrange throttle valve.
In addition, the oil circuit between accumulator 33 and solenoid directional control valve 32 is also provided with and detects mouth MA, to compress into row to guide oil detecting guarantee system acting safety.And, in order to reduce the impurity in guide's fluid as far as possible, filter can also be set in oil inlet P 7 and P2 place.
Hydraulic system of the present utility model is in order to control more reliably variable displacement pump 2, as shown in Figure 6, also be provided with pilot-actuated valve block 28, pilot-actuated valve block 28 is for screening load pressure signal larger in the first executive component and the second executive component, and feed back to the variable control mechanism of the variable displacement pump 2 in variable pump systems as load feedback signal, and then the oil pump capacity of controlled variable pump 2.
Further, pilot-actuated valve block 28 comprises shuttle valve and the 3rd throttle orifice 30, two filler opening LS1 and m of shuttle valve are respectively used to the load pressure signal of reception first executive component and the second executive component, the oil outlet LS2 of shuttle valve is provided with the 3rd throttle orifice 30, by shuttle valve, larger load pressure signal in the first executive component and the second executive component is screened, and then feed back to the LS3 mouth of variable control mechanism of variable displacement pump 2 as load feedback signal, and then the oil pump capacity of controlled variable pump 2.3rd throttle orifice 30 is integrated to be assemblied in pilot-actuated valve block 28, but also can change.
In another embodiment, in order to eliminate the compression shock of variable displacement pump 2 oil outlet, constant difference overflow valve 29 is also provided with in opening and closing core hydraulic system, constant difference overflow valve 29 is arranged between the oil feeding line of variable pump systems and oil return circuit, the filler opening of constant difference overflow valve 29 is communicated with the oil outlet P1 of variable displacement pump 2, oil outlet is communicated with hydraulic oil container 1, and spring chamber is communicated with the oil outlet LS2 of pilot-actuated valve block 28.Now, the oil outlet pressure of variable displacement pump 2 is determined jointly by the pressure of LS3 mouth and constant difference overflow valve 29 pressure adjusting spring.
If do not arrange constant difference overflow valve 29, when the first executive component stops action suddenly, opening and closing core control valve block 9 can be made to close rapidly, now the discharge capacity of variable displacement pump 2 does not also have enough time to reduce, this can cause pumping hole to occur high compression shock, this surge pressure, once exceed the cut-out pressure of variable displacement pump 2, will cause variable displacement pump 2 row of going back to rapidly.After being provided with constant difference overflow valve 29, if the first executive component stops action suddenly, so opening and closing core control valve block 9 can be closed rapidly, although now the discharge capacity of variable displacement pump 2 does not have enough time to reduce, but the pressure of constant difference overflow valve 29 spring chamber can reduce rapidly, at this moment the pressure that variable displacement pump 2 exports is decided by the set pressure of spring, and hydraulic oil can through the oil outlet overflow meeting hydraulic oil container 1 of constant difference overflow valve 29, and this can make compression shock greatly reduce.Equally, when opening and closing core control valve block 9 is opened suddenly, the discharge capacity of variable displacement pump 2 can increase suddenly, if when the hydraulic oil provided exceedes the requirements of load, also can carry out overflow by constant difference overflow valve 29, thus reduces to impact.
In addition, the utility model additionally provides a kind of engineering machinery, comprises the opening and closing core hydraulic system of above-described embodiment.Preferably, this project machinery can be loader, it turns to, swing arm is elevated and the action such as scraper bowl shoveling all relies on hydraulic system to control, a specific embodiment as shown in Figure 6, wherein the first executive component comprises tipping bucket cylinder 12 and swing arm cylinder 13, second executive component comprises left steering cylinder 7 and right steering cylinder 8.
Further, Constant Pump System comprises metering pump 18, pilot valve 14 and distributing valve 11, distributing valve 11 is arranged on the oil feeding line of metering pump 18, and pilot valve 14 can provide control signal for distributing valve 11, thus controls one of the two in tipping bucket cylinder 12 and swing arm cylinder 13 execution expanding-contracting action.In addition, for some more specifically parts in Constant Pump System, draw when introducing the concrete structure of Constant Pump System below in the lump.
Wherein, the oil inlet P 4 of pilot valve 14 receives the hydraulic oil that the first hydraulic fluid port XS from pilot control block 10 provides, and inside arranges four switch electromagnetic valves, oil inlet P 4 can be realized be communicated with corresponding oil outlet by opening some switch electromagnetic valves, oil outlet a1, a2, b1 and b2 respectively with the control port A1 of distributing valve 11, A2, B1 with B2 is communicated with, by logical oily to control port A1 or B1 of distributing valve 11, the piston rod that can control tipping bucket cylinder 12 stretches out or retracts, perform corresponding to scraper bowl and regain and outer swing work, by logical oily to control port A2 or B2 of distributing valve 11, the piston rod that can control swing arm cylinder 13 stretches out or retracts, perform corresponding to swing arm and lift or drop action.
In addition; the oil inlet P 3 of distributing valve 11 is communicated with load hydraulic fluid port P6; and distributing valve 11 inside is also provided with equilibrium valve and Pilot operated check valve; be connected with the rod chamber of tipping bucket cylinder 12 or swing arm cylinder 13 respectively; the large chamber rapid decompression of tipping bucket cylinder 12 or swing arm cylinder 13 can be prevented and cause piston rod to retract; this is very dangerous in the loaded situation of oil cylinder band; and when piston rod is retracted; can preventing load inertia from causing, oil return speed is too fast causes danger; cause oil cylinder to damage, play balance, protection and locking effect.And, be also provided with the parts for removing locking in pilot valve 14, as hydraulic control on-off valve, as long as pilot control block 10 provides guide fluid to Constant Pump System, hydraulic control on-off valve is then connected, will by the hydraulic fluid port 2C fuel feeding of the hydraulic fluid port 2c of pilot valve 14 to distributing valve 11, then Pilot operated check valve is opened.
In addition, in order to make tipping bucket cylinder 12 and swing arm cylinder 13 can not action simultaneously, form is communicated with by the hydraulic fluid port of the meta and position, left and right that arrange two selector valves in distributing valve 11, oil can not be led to swing arm cylinder 13 when can realize 12 action of tipping bucket cylinder, to the logical oil of tipping bucket cylinder 12, the alternative of tipping bucket cylinder 12 and swing arm cylinder 13 action can not be this guarantees during 13 action of swing arm cylinder.Further, in order to improve the Security of distributing valve 11 further, relief valve can also be set between the oil inlet P 3 of distributing valve 11 and oil return inlet T 3.
Further, variable pump systems comprises: variable displacement pump 2, flux amplification valve 6 and commutator 3, flux amplification valve 6 is arranged on the oil feeding line of variable displacement pump 2, and commutator 3 can provide control signal for flux amplification valve 6, thus control left steering cylinder 7 and right steering cylinder 8 perform expanding-contracting action.In addition, for some more specifically parts in variable pump systems, draw when introducing the concrete structure of variable pump systems below in the lump.
Wherein, the hydraulic oil that the second hydraulic fluid port XZ that the oil inlet P of commutator 3 receives pilot control block 10 provides, oil outlet L and R of commutator 3 is respectively by left limit valve 5 and right limit valve 4, be communicated with left side hydraulic control mouth with the right side hydraulic control mouth of the hydraulic control proportional reversing valve 61 in flux amplification valve 6, left limit valve 5 and right limit valve 4 can control the break-make of these two oil circuit controls respectively, and, two hydraulic control mouths of hydraulic control proportional reversing valve 61 are communicated with the hydraulic control mouth of offside respectively by restriction, like this when arbitrary hydraulic control mouth passes into fluid, will and the hydraulic control mouth of offside between form pressure reduction, thus impel hydraulic control proportional reversing valve 61 faster, more easily realize commutation, from another angle, this design can play the effect that assisted diversion device 3 carries out commutation control.
Secondly, the oil inlet P 1 of flux amplification valve 6 is communicated with the oil outlet of metering pump 2, pressure-gradient control valve 62 is set between oil inlet P 1 and hydraulic control proportional reversing valve 61, pressure-gradient control valve 62 is subject to the Stress control from variable pump systems and steering cylinder load simultaneously, and three of pressure-gradient control valve 62 difference can realize according to different ratios respectively to steering system and work system fuel feeding, when pressure-gradient control valve 62 is in right position, variable displacement pump 2 gives steering system fuel feeding; When pressure-gradient control valve 62 is in meta, variable displacement pump 2 by according to larger ratio to steering system fuel feeding, and with less ratio by hydraulic fluid port EF fuel feeding, the operating mode that the operating load of loader is less can only be applicable to owing to being subject to throttling action on the oil circuit giving work system fuel feeding; When pressure-gradient control valve 62 is in left position, variable displacement pump 2 with less ratio fuel feeding, and can only pass through hydraulic fluid port EF to work system fuel feeding according to larger ratio owing to being subject to throttling action on the oil circuit giving steering system fuel feeding, is applicable to the operating mode of loader heavy duty work.In addition, in order to the work safety of flux amplification valve 6, between its oil inlet P 1 and oil return inlet T 1, also relief valve is provided with.
In addition, also shuttle valve is provided with in flux amplification valve 6, two filler opening L2 with R2 of shuttle valve are connected with right steering cylinder 8 with left steering cylinder 7 respectively, oil outlet LS is communicated with one of them filler opening LS1 of pilot-actuated valve block 28, and this shuttle valve is used for obtaining larger induced pressure in steering system and is supplied to the LS1 mouth of pilot-actuated valve block 28.
And in this opening and closing core hydraulic system, Constant Pump System and variable pump systems also also exist crosslinked relation, pilot control block 10 provides guide fluid respectively by the hydraulic fluid port P of hydraulic fluid port P4 and commutator 3 that the first hydraulic fluid port XS and the second hydraulic fluid port XZ is respectively pilot valve 14; Opening and closing core control valve 9 is hydraulic control proportional control valve, its filler opening EF1 is communicated with the EF mouth of flux amplification valve 6, oil outlet P8 and control port n are all communicated with the hydraulic fluid port P3 (reflecting the induced pressure of work system) of distributing valve 11, in order to receive the induced pressure of work system, when pressure P 3 reaches certain value, opening and closing core control valve block 9 is opened; Pilot-actuated valve block 28 is shuttle valve, two filler opening LS1 with m is communicated with the hydraulic fluid port P3 of distributing valve 11 with the LS mouth of flux amplification valve 6 respectively, oil outlet LS2 is communicated with the hydraulic fluid port LS3 of the variable control mechanism of variable displacement pump 2, is used for filtering out the fuel delivery that induced pressure larger in steering system and work system carrys out controlled variable pump 2.
Set forth to the working principle of the opening and closing core hydraulic system shown in Fig. 6 in detail below.
When loader is at straight line moving, due to steering system and the equal attonity of work system, the LS2 hydraulic fluid port no signal of pilot-actuated valve block 28 exports, and variable displacement pump 2 is standby, the off-load of metering pump 18 meta, and opening and closing core control valve block 9 is in and closes wick-like state.
When loader in the process of moving, when only having steering system single movement, because distributing valve 11 is for leaving core, the pressure drop that the flow of metering pump 18 is formed by its meta is less, be not enough to open opening and closing core control valve 9, so opening and closing core control valve 9 is still in close wick-like state, to reduce the energy loss of variable displacement pump 2, energy saving of system successful.
When loader work system also simultaneously action time, the valve port of distributing valve 11 turns down gradually, and induced pressure P3 raises gradually, when the cracking pressure of system pressure higher than opening and closing core control valve block 9, the flow that variable displacement pump 2 provides becomes large gradually, collaborates fuel feeding to work system with metering pump 18.When work system stops action, induced pressure P3 reduces, and opening and closing core control valve 9 is again got back to and closed core position, to reduce the loss of variable displacement pump 2.
Under the operating mode of steering system and work system action simultaneously, also may correspond to following two kinds of mode of operations: (1) in the normal mode of operation, mode of operation diverter switch 26 must not be electric, and whether off-load is determined by the pressure of load feedback hydraulic fluid port P6 unloading valve block 17.(2) when pressing mode of operation diverter switch 26, unloading valve block 17 is in pressure unloading condition, and now hydraulic system switches to entire variable system by quantitative and set of variables assembly system.Now, the movement speed of scraper bowl or swing arm can be slack-off, but be variable system due to work system and steering system, can have good handling and micro-control, and energy-saving effect is obvious, is applicable to low speed super-heavy load shovel dress operating mode and needs to ensure the operating mode of control performance.
Such as in spading process, after the pressure of load feedback hydraulic fluid port P6 reaches the setting pressure of relief valve 25, start off-load, thus protection metering pump 18, prevent excess traffic overflow, save engine power.Now, the high pressure of work system is born by variable displacement pump 2, when system pressure raises further, when reaching the cut-out pressure of variable displacement pump 2, the discharge capacity of variable displacement pump 2 automatically return drain into minimum, eliminate spill losses, thus reach off-load buffering with protection object.
Opening and closing core hydraulic system of the present utility model, except being used in loader, can also be used in the engineering machinery of other type, such as excavator etc.From Fig. 6 and above description known, the opening and closing core hydraulic system in the utility model loader also tool one of has the following advantages, and in describing above, the advantage mentioned will repeat no more here:
(1) have employed more integrated valve block, such as unloading valve block 17, pilot control block 10 and pilot-actuated valve block 28 etc., pipeline can be reduced and connect, simplify the structure of hydraulic system, and installation can be made and keep in repair convenient.
(2) this hydraulic system has stable unloading function, unloading valve block will be caused frequently to open and close because of system pressure fluctuation, thus eliminate system vibration and impact, extend the working life of each element and system.
(3) pilot-actuated valve block 28 carries out Time-sharing control according to the size of flux amplification valve 6 feedback signal LS, when the load of work system is larger, the interference of steering system to variable displacement pump 2 can be eliminated, only according to the feedback signal of work system, variable displacement pump 2 is controlled, thus improve the stability of steering system, and reduce energy consumption.
(4) for determining variable, to combine this flow larger, and variable displacement pump 2 is the hydraulic system of steering system fuel feeding, by adopting pilot control block 10 as steering system independently pilot control, small displacement can be chosen and close core commutator 3, thus by the low traffic requirement to commutator 3.And, adopt the commutator 3 of small displacement as the hydraulic pilot level of flux amplification valve 6, the restriction loss of commutator 3 inside during fast steering can be eliminated, to reduce fuel oil oil consumption, can also steering stability be increased simultaneously.
Above a kind of unloading valve block provided by the utility model, opening and closing core hydraulic system and engineering machinery are described in detail.Apply specific embodiment herein to set forth principle of the present utility model and mode of execution; the explanation of above embodiment just understands method of the present utility model and core concept thereof for helping, and all employings are equal to the scheme of replacement formation all in the protection domain of this patent.For those skilled in the art, under the prerequisite not departing from the utility model principle, can also carry out some improvement and modification to the utility model, these improve and modify and also fall in the protection domain of the utility model claim.

Claims (24)

1. a unloading valve block, it is characterized in that, for being arranged between the oil feeding line of hydraulic system and oil return circuit, comprise: the mode of operation of the first valve body, unloading valve (22) and external control switches on-off valve (19), the filler opening of described unloading valve (22) is communicated with return opening (T5) with the filler opening (P5) of described first valve body respectively with oil outlet, switches on-off valve (19) turn on and off between the control port of described unloading valve (22) and described return opening (T5) by described mode of operation.
2. unloading valve block according to claim 1, it is characterized in that, described unloading valve (22) is cartridge valve, described cartridge valve is provided with the first filler opening (22A), first oil outlet (22B) and the first control port (22C), described first filler opening (22A) is communicated with return opening (T5) with the filler opening (P5) of described first valve body respectively with described first oil outlet (22B), the oil circuit that described first control port (22C) is communicated with the filler opening (P5) of described first valve body is provided with first segment discharge orifice (23), described mode of operation switches on-off valve (19) and is arranged on the oil circuit between described first control port (22C) and the return opening (T5) of described first valve body.
3. unloading valve block according to claim 2, it is characterized in that, also comprise relief valve (25), described relief valve (25) is arranged on the oil circuit between described first segment discharge orifice (23) and the return opening (T5) of described first valve body.
4. unloading valve block according to claim 3, it is characterized in that, described first valve body is provided with load feedback hydraulic fluid port (P6), and described load feedback hydraulic fluid port (P6) is communicated with the control chamber without spring side of described relief valve (25).
5. unloading valve block according to claim 3, is characterized in that, the return opening (T5) of described first valve body is communicated with the control chamber of the spring side of described relief valve (25).
6. according to the arbitrary described unloading valve block of claim 2 ~ 5, it is characterized in that, the variable orifice (20) by being arranged in parallel between the filler opening (P5) of described first valve body and first filler opening (22A) of described cartridge valve is communicated with the first one-way valve (21).
7., according to the arbitrary described unloading valve block of claim 2 ~ 5, it is characterized in that, also comprise the second section discharge orifice (27) at the first control port (22C) place being arranged on described cartridge valve.
8. unloading valve block according to claim 4, it is characterized in that, also comprise be arranged on described first valve body the oil circuit between filler opening (P5) and load feedback hydraulic fluid port (P6) on the second one-way valve (24), the filler opening (P5) of described first valve body is by described second one-way valve (24) and described load feedback hydraulic fluid port (P6) unilaterally connected.
9. an opening and closing core hydraulic system, it is characterized in that, comprise: the arbitrary described unloading valve block (17) of Constant Pump System, variable pump systems, at least one first executive component, at least one second executive component, opening and closing core control valve block (9) and claim 1 ~ 8
Described Constant Pump System is described first executive component fuel feeding, and described unloading valve block (17) is arranged between oil feeding line in described Constant Pump System and oil return circuit;
On oil circuit between the oil feeding line that described opening and closing core control valve block (9) is arranged on described Constant Pump System and described variable pump systems, opening and closing can be realized, to make described variable pump systems simultaneously for described first executive component and the second executive component fuel feeding or separately for described second executive component fuel feeding according to the induced pressure (P3) of described first executive component.
10. opening and closing core hydraulic system according to claim 9, it is characterized in that, also comprise mode of operation diverter switch (26), it is electromagnetic switch valve that described mode of operation switches on-off valve (19), and the control end of described electromagnetic switch valve is connected with described mode of operation diverter switch (26).
11. opening and closing core hydraulic systems according to claim 9, it is characterized in that, the oil return circuit of described Constant Pump System is provided with radiator (16) and oil return filter cleaner (15), and the return opening (T5) of described unloading valve block (17) is connected on the oil circuit between described radiator (16) and described oil return filter cleaner (15).
12. opening and closing core hydraulic systems according to claim 9, it is characterized in that, described opening and closing core control valve block (9) is hydraulic control proportional control valve, and the openings of sizes of described opening and closing core control valve block (9) can be adjusted by the induced pressure (P3) of described first executive component.
13. opening and closing core hydraulic systems according to claim 9, it is characterized in that, mode of operation switches on-off valve (19) when described first actuator movement is to the predeterminated position of its travel end, can control described unloading valve (22) initiatively off-load.
14. opening and closing core hydraulic systems according to claim 9, it is characterized in that, also comprise pilot control block (10), described pilot control block (10) is arranged on the oil feeding line in described variable pump systems, and the action that can be respectively described first executive component and described second executive component provides control fluid.
15. opening and closing core hydraulic systems according to claim 14, it is characterized in that, described pilot control block (10) comprising: the second valve body, reduction valve (31) and solenoid directional control valve (32), the filler opening (P7) of described second valve body is communicated with the oil feeding line of described variable pump systems, and first oil outlet (XS) of described second valve body is connected with the oil circuit control of described Constant Pump System and described variable pump systems respectively with the second oil outlet (XZ);
Described reduction valve (31) is arranged between the filler opening (P7) of described second valve body and second oil outlet (XZ) of described second valve body, described solenoid directional control valve (32) is arranged between the oil outlet of described reduction valve (31) and first oil outlet (XS) of described second valve body, can control described pilot control block (10) to the break-make of the oil circuit control fuel feeding of described Constant Pump System.
16. opening and closing core hydraulic systems according to claim 15, it is characterized in that, described pilot control block (10) also comprises accumulator (33), and described accumulator (33) is arranged on the oil circuit between described reduction valve (31) and described solenoid directional control valve (32).
17. opening and closing core hydraulic systems according to claim 9, it is characterized in that, also comprise pilot-actuated valve block (28), described pilot-actuated valve block (28) is for screening load pressure signal larger in described first executive component and described second executive component, and feed back to the variable control mechanism of the variable displacement pump (2) in described variable pump systems as load feedback signal, and then control the oil pump capacity of described variable displacement pump (2).
18. opening and closing core hydraulic systems according to claim 17, it is characterized in that, described pilot-actuated valve block (28) comprises shuttle valve and the 3rd throttle orifice (30), two filler openings of described shuttle valve are respectively used to the load pressure signal receiving described first executive component and described second executive component, the oil outlet of described shuttle valve is provided with described 3rd throttle orifice (30), is screened larger load pressure signal in described first executive component and described second executive component by described shuttle valve.
19. opening and closing core hydraulic systems according to claim 17, it is characterized in that, also comprise constant difference overflow valve (29), between the oil feeding line that described constant difference overflow valve (29) is arranged on described variable pump systems and oil return circuit, the spring chamber of described constant difference overflow valve (29) is communicated with the oil outlet of described pilot-actuated valve block (28).
20. opening and closing core hydraulic systems according to claim 9, it is characterized in that, described first executive component is Job execution element, and described second executive component is non-Job execution element.
21. 1 kinds of engineering machinery, is characterized in that, comprise the arbitrary described opening and closing core hydraulic system of claim 9 ~ 20.
22. engineering machinery according to claim 21, it is characterized in that, described engineering machinery is loader, described first executive component comprises tipping bucket cylinder (12) and swing arm cylinder (13), and described second executive component comprises left steering cylinder (7) and right steering cylinder (8).
23. engineering machinery according to claim 22, it is characterized in that, described Constant Pump System comprises metering pump (18), pilot valve (14) and distributing valve (11), described distributing valve (11) is arranged on the oil feeding line of described metering pump (18), described pilot valve (14) can provide control signal for described distributing valve (11), thus controls one of the two in described tipping bucket cylinder (12) and described swing arm cylinder (13) execution expanding-contracting action.
24. engineering machinery according to claim 22, it is characterized in that, described variable pump systems comprises: variable displacement pump (2), flux amplification valve (6) and commutator (3), described flux amplification valve (6) is arranged on the oil feeding line of described variable displacement pump (2), described commutator (3) can provide control signal for described flux amplification valve (6), thus controls described left steering cylinder (7) and described right steering cylinder (8) execution expanding-contracting action.
CN201520652489.0U 2015-08-26 2015-08-26 Unloading valve piece, switching core hydraulic system and engineering machinery Withdrawn - After Issue CN204985136U (en)

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Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN105090154A (en) * 2015-08-26 2015-11-25 徐工集团工程机械股份有限公司科技分公司 Unloading valve block, opening and closing core hydraulic system and engineering machine
CN106759620A (en) * 2016-12-29 2017-05-31 潍柴动力股份有限公司 A kind of excavator synchronous control system and excavator
CN108483264A (en) * 2018-06-20 2018-09-04 徐州重型机械有限公司 The hydraulic control system and hoisting machinery of hoisting machinery
US10822025B1 (en) 2019-09-18 2020-11-03 Caterpillar Sarl Hydraulic valve module for steering and work functions in a work vehicle

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN105090154A (en) * 2015-08-26 2015-11-25 徐工集团工程机械股份有限公司科技分公司 Unloading valve block, opening and closing core hydraulic system and engineering machine
CN106759620A (en) * 2016-12-29 2017-05-31 潍柴动力股份有限公司 A kind of excavator synchronous control system and excavator
CN108483264A (en) * 2018-06-20 2018-09-04 徐州重型机械有限公司 The hydraulic control system and hoisting machinery of hoisting machinery
CN108483264B (en) * 2018-06-20 2019-06-25 徐州重型机械有限公司 The hydraulic control system and hoisting machinery of hoisting machinery
US10822025B1 (en) 2019-09-18 2020-11-03 Caterpillar Sarl Hydraulic valve module for steering and work functions in a work vehicle

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