CN1170831A - Hydraulic system for power loaders - Google Patents
Hydraulic system for power loaders Download PDFInfo
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- CN1170831A CN1170831A CN97112245A CN97112245A CN1170831A CN 1170831 A CN1170831 A CN 1170831A CN 97112245 A CN97112245 A CN 97112245A CN 97112245 A CN97112245 A CN 97112245A CN 1170831 A CN1170831 A CN 1170831A
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- branch
- oil
- pump
- oil circuit
- control
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Classifications
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
- F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
- F15B11/00—Servomotor systems without provision for follow-up action; Circuits therefor
- F15B11/02—Systems essentially incorporating special features for controlling the speed or actuating force of an output member
- F15B11/04—Systems essentially incorporating special features for controlling the speed or actuating force of an output member for controlling the speed
- F15B11/044—Systems essentially incorporating special features for controlling the speed or actuating force of an output member for controlling the speed by means in the return line, i.e. "meter out"
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- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02F—DREDGING; SOIL-SHIFTING
- E02F9/00—Component parts of dredgers or soil-shifting machines, not restricted to one of the kinds covered by groups E02F3/00 - E02F7/00
- E02F9/20—Drives; Control devices
- E02F9/22—Hydraulic or pneumatic drives
- E02F9/2278—Hydraulic circuits
- E02F9/2296—Systems with a variable displacement pump
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- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02F—DREDGING; SOIL-SHIFTING
- E02F9/00—Component parts of dredgers or soil-shifting machines, not restricted to one of the kinds covered by groups E02F3/00 - E02F7/00
- E02F9/20—Drives; Control devices
- E02F9/22—Hydraulic or pneumatic drives
- E02F9/2217—Hydraulic or pneumatic drives with energy recovery arrangements, e.g. using accumulators, flywheels
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- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02F—DREDGING; SOIL-SHIFTING
- E02F9/00—Component parts of dredgers or soil-shifting machines, not restricted to one of the kinds covered by groups E02F3/00 - E02F7/00
- E02F9/20—Drives; Control devices
- E02F9/22—Hydraulic or pneumatic drives
- E02F9/2221—Control of flow rate; Load sensing arrangements
- E02F9/2232—Control of flow rate; Load sensing arrangements using one or more variable displacement pumps
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- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02F—DREDGING; SOIL-SHIFTING
- E02F9/00—Component parts of dredgers or soil-shifting machines, not restricted to one of the kinds covered by groups E02F3/00 - E02F7/00
- E02F9/20—Drives; Control devices
- E02F9/22—Hydraulic or pneumatic drives
- E02F9/2278—Hydraulic circuits
- E02F9/2282—Systems using center bypass type changeover valves
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- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02F—DREDGING; SOIL-SHIFTING
- E02F9/00—Component parts of dredgers or soil-shifting machines, not restricted to one of the kinds covered by groups E02F3/00 - E02F7/00
- E02F9/20—Drives; Control devices
- E02F9/22—Hydraulic or pneumatic drives
- E02F9/2278—Hydraulic circuits
- E02F9/2285—Pilot-operated systems
Abstract
A hydraulic system for power loaders, selectively changing the amount of pump discharged oil in accordance with an operational condition of a loader and improving operational efficiency of the loader. The system has a swash plate-type main pump for discharging pressurized oil for working and steering parts of the system, a swash plate-type pilot pump for discharging pressurized oil for a pilot signal output control lever, and a regulator. The regulator is mounted to a first branch oil passage branched from a main oil passage extending from each of the main and pilot pumps. The regulator selectively controls the angle of the swash plate of each of the main and pilot pumps in accordance with a variable pressure of the first branch passage.
Description
In general, the present invention relates to the hydraulic system of Architectural Equipment, more particularly, relate to the hydraulic system of power loader.This system has the main pump and the control pump of belt variable swash plate, like this, can change the oil transportation amount of pump selectively according to the operating conditions of loader, and improve the working efficiency of loader.
Those of ordinary skill in the art knows that power loader is a kind of form of building machinery, is used for the bulk cargo bailing bucket such as sand or cobble one class is dug and is contained in, for example, on the dump truck.This loader is to be operated by the hydraulic system that has main pump and operate pump.Main pump and operate pump are driven by engine output power, and respectively output for the pressure oil of operating cylinder (for example lift cylinder and the dump ram that links to each other with scraper bowl with suspension rod) usefulness with for handling the pressure oil that oil cylinder is used.
Fig. 2 represents the structure of the typical hydraulic system of power loader.Main pump and the operate pump of representing system among the figure respectively with label 2 and 3.System also comprises a plurality of manipulations and operating cylinder 10,17 and 18.Operating cylinder 17 and 18 example are lift cylinders, dump ram etc.Operating cylinder 17 and 18 is handled by the output oil of main pump 2, drives workpiece motion (for example suspension rod and scraper bowl).Simultaneously, handle the output oil driving of oil cylinder 10 by operate pump 3, thus the steering maneuver loader.For the flow direction of the pressure oil of Control work oil cylinder 17 and 18,18 and 17 working oil path of extending, two position control valves 14 and 16 have been installed from main pump 2 to operating cylinder.From operate pump to handling the manipulation oil circuit that oil cylinder 10 extends, manipulation guiding valve 6 has been installed.This handles the signalizing activity of guiding valve 6 according to the motion of expression operator manipulation wheel (not shown).This system also comprises an instruction guiding valve 5.This guiding valve 5 is according to the control signal of handling oil circuit, Control work oil circuit and handle the pressure oil mass of oil circuit.
In Fig. 2, label 1 expression fuel tank, 4 expressions are installed in connection work and handle the one-way valve on the passage of interconnecting of oil circuit, and the safety valve of oil circuits is handled in 7 expressions, the safety valve of 11 expression working oil path, 8 expressions are handled the suction valve of oil circuit and the suction valve of 12 expression working oil path.
When the internal combustion engine start of loader, pressure oil outputs to control valve 14 and 16 from main pump 2 by passage 2A.Valve 14 and 16, before oil is sent into operating cylinder 17 and 18, the direction of control oil flow.Simultaneously, operate pump 3 transfers to pressure oil and handles guiding valve 6, and therefore, guiding valve 6 can be before sending into oil manipulation oil cylinder 10, the flow direction of control oil.
When loader is in neutral condition or do not have the state of load, the oil of pump output is not by working oil path or handle oil circuit, like this, make oil cylinder 10,17 and 18 stop motions, under this neutral condition, the spool of each control valve is in its middle position, therefore, the oil from two pumps 2 and 3 outputs flows back in the fuel tank 1 by control valve.In typical power loader hydraulic system, adopt metering pump each pump as pump 2 and 3.The swash plate of this metering pump is fixed, no matter make working state how, the oil mass of pump output is all fixed.Have the fixedly pump 2 and the pump 3 of swash plate, even the oil mass of exporting fixes also under neutral condition, so just wasted the output power of motor or pump.This pump 2 and pump 3 also make fixing oil mass by each control valve, have so just reduced the life-span of each valve and the expected life of system.
Therefore, consider the problems referred to above that occur in the prior art, proposed the present invention.An object of the present invention is to provide a kind of hydraulic system of power loader, this system can reduce the oil mass of pump output selectively under the neutral condition of loader, thereby saves the output power and the working efficiency of improving loader of motor.
Another object of the present invention is the hydraulic system that a kind of power loader will be provided, and therefore this system even be at loader and also can keep the pressure in the oil circuit constant under the neutral condition has effectively improved the response performance of loader.
Another purpose of the present invention is the hydraulic system that a kind of power loader will be provided, this system is under loader is in neutral condition, allow the oil of pump output to pass through by-pass line, main pump is worked under the condition that does not have load, save the output power of pump, prevent that pump is undesirable overheated, prolong the expected life of pump, prevent oily temperature rise and avoid service behaviour to reduce or the undesirable damage of actuator.
In one aspect, the invention provides a kind of hydraulic system of power loader, it comprises one with the work of the pressure oil supply system of output and ramp type main pump and ramp type operate pump with a control of the pressure oil supply lever of output of actuating element.Control signal of this control lever output is given the control valve of working portion.This hydraulic system also comprises a regulator, and this regulator is installed in from first branch's oil circuit that the working connection branch that is extended out by each pump main pump and the control pump comes.This regulator is used for the change pressure according to first branch's oil circuit, controls the swash plate inclination angle of each pump in main pump and the control pump selectively.
This regulator comprises a servo-cylinder.This servo-cylinder has: piston and offset assembly, and second branch's oil circuit, the 3rd branch's oil circuit interconnects path, an aperture and a Proportional valve.This piston is contained in the servo-cylinder and can moves, and it divides loculation and big chamber with the inside of servo-cylinder, and this piston is connected with the swash plate of each pump in the control pump with main pump.This offset assembly is installed in the big chamber of servo-cylinder, and piston is offset towards loculus.This second branch oil circuit comes out from the first oil circuit branch of branch, leads to the loculus of servo-cylinder.The 3rd branch's oil circuit comes out from the first oil circuit branch of branch, leads to the big chamber of servo-cylinder.This interconnects path and extends out from first branch's oil circuit, and the second and the 3rd branch's oil circuit is linked together.This aperture is installed in this and interconnects on the passage, is used for suppressing selectively the oil mass of the 3rd branch's oil circuit.This Proportional valve is installed in from the 3rd branch's oil circuit and extends on the oil circuit on oil extraction road, this Proportional valve is subjected to the skew effect of offset member, can be according to the skew pressure of offset member and the oil pressure in second branch's oil circuit poor, selectively the oil of the 3rd branch's oil circuit is discharged by the oil extraction road.
The skew pressure of offset member is adjusted by the user.
This hydraulic system also comprises an accumulator and one-way valve.This accumulator is installed on the working connection, is used for storing the unnecessary oil of main pump and each pump output of control pump.This one-way valve is installed in the main pump of working connection and the control pump on the position between each pump and accumulator, is used for preventing that the oil that stores from blowing back into each pump from accumulator, and main kind is flow backwards is undesirable.
This hydraulic system also comprises an oil passage control valve, and it is installed in from working connection branch, and leads on the 4th branch's oil circuit on oil extraction road.This oil passage control valve is used for closing under the normal condition the 4th branch's oil circuit and according to the signal that is predetermined, opens the 4th branch's oil circuit selectively.
On the other hand, the invention provides a kind of hydraulic system of power loader.This system comprises a ramp type main pump, is used for the work and the actuating element of system that pressure oil is transferred to; With a ramp type control pump, be used for pressure oil and transport to the control lever.This controlling rod output control signal is given the control valve of working portion.In addition, this hydraulic system also comprises: a regulator, it is installed on first branch's oil circuit that each pump extends out from main pump and control pump working connection branch comes out, be used for change pressure, control the inclination angle of the swash plate of each pump in main pump and the control pump selectively according to first branch's oil circuit.This hydraulic system also comprises the accumulator that is installed on the working connection and is used for storing the unnecessary oil of the output of main pump and each pump of control pump; Be installed on the working connection, on the position in main pump and the control pump between each pump and the accumulator, and be used for preventing that the oil that is stored from undesirably blowing back into the one-way valve of each pump from accumulator; With the oil passage control valve that is installed on the 4th branch's oil circuit that leads to the oil extraction road that comes out from working connection branch.This oil passage control valve is used for closing under the normal condition the 4th branch's oil circuit and according to the signal that is predetermined, opens the 4th branch's oil circuit selectively.
From the detailed description of doing below in conjunction with accompanying drawing, will become apparent above-mentioned and some other purpose of the present invention, characteristics and other advantages, wherein:
Fig. 1 a is the view of the structure of expression power loader hydraulic system according to a preferred embodiment of the invention;
Fig. 1 b is for representing to have the view according to the main pump of improved regulator of the present invention in detail; With
Fig. 2 represents the structure of a typical power loader hydraulic system.
Fig. 1 a and 1b represent the structure of the hydraulic system of power loader according to a preferred embodiment of the invention.As shown in the figure, hydraulic system of the present invention comprises working portion and the part of advancing, and they are to be handled by the working connection or the first oil circuit 1A by the pressure oil of main pump 1 output.The advance travel section branch of condition of control power loader comprises that control member 3 and two handle oil cylinders 11 and 12.Control member 3 is controlled the pressure oil of the 1st oil circuit 1A according to the control signal of expression operator manipulation wheel (not shown) motion.Handle oil cylinder 11 and 12 and be under the control of control member 3 by pressure oil driving work, thereby can handle loader.The part of advancing also comprises a vibration damping equipment 13, undesirably is added in the impact in the system when it can remove loader operation.
Simultaneously, the working portion of control loader workpiece (for example suspension rod or scraper bowl) comprises major control parts 4, and it can be according to control signal a, b, c, d, f, the pressure oil that g or h control are flowed by the 1st oil circuit 1A.Two oil cylinders, perhaps dump ram 16 is connected with major control parts 4 with lift cylinder 17, and handles workpiece respectively, or scraper bowl and suspension rod.Working portion also comprises a safety valve 15, and it is limited in the level that is predetermined with the oil pressure of hydraulic system, can protect the unlikely infringement that is subjected to undesirable excessive pressure of hydraulic system like this.
This hydraulic system also comprises control lever segment 5, and it is installed on the second oil circuit 2A that extends out from control pump 2.Lever part 5 is according to operator's maneuvering motion output control signal.The pressure oil of lever segment 5 is by 19 controls of control signal output block.
In Fig. 1 a and 1b, the urgent control member of label 18 expressions, the cooler of 20 expression cooling oil returns, 21 expression fuel tanks, 22 expression air exchangers.
This hydraulic system also has regulator 9, accumulator 7 and one-way valve 6.Regulator 9 is connected with the 1st oil circuit 1A by the first oil circuit 9A of branch, thereby can receive the next feedback pressure from the first oil circuit 1A, and changes the inclination angle of the swash plate of main pump 1.Like this, can change the output oil mass of pump 1.Accumulator 7 is installed on the 1st oil circuit 1A, and the unnecessary oil of storage pump 1 output, can keep the desirable oil pressure among the 1st oil circuit 1A of the part of advancing of working portion like this.One-way valve 6 prevents that the oil that stores from undesirably blowing back into the pump 1 from accumulator 7.
When loader was in working state or travel condition, regulator 9 increased the swash plate inclination angle of main pump 1, thereby the output oil mass of pump 1 is increased to maximum according to the feedback pressure that comes from the 1st oil circuit 1A.On the contrary, when neutral condition, regulator 9 reduces the swash plate inclination angle of pump 1, thereby the output oil mass of pump 1 is decreased to minimum.In order to finish above-mentioned work, regulator 9 has 90, one apertures 96 of servo-cylinder and Proportional valve 97, and the 2nd and the 3rd oil circuit 90A of branch and 90B come out from the first oil circuit 9A branch of branch.Servo-cylinder 90 has two chambeies: loculus 91 and big chamber 92, they are communicated with the second and the 3rd oil circuit 90A of branch and 90B respectively.Aperture 96 is installed in and interconnects on the passage 90C, and this passage extends out from the 1st oil circuit 9A of branch, simultaneously the 2nd and the 3rd oil circuit 90A of branch and 90B is linked together.Proportional valve 97 is subjected to the skew effect of second offset member 98, and therefore, what valve 97 can be according to the skew pressure of offset member 98 and the oil pressure in the 2nd oil circuit 90A of branch is poor, and the 3rd oil circuit 90B of branch is communicated with oil extraction road 21A.Piston 93 is installed in the servo-cylinder 90 and can moves.And piston rod 94 is connected the swash plate of piston 93 with main pump 1, like this, can change the inclination angle of swash plate according to the straight line motion of piston 93 in oil cylinder 90 selectively, servo-cylinder 90 also has one first offset member 95, it is installed in the big chamber 92 of oil cylinder 90, and under normal circumstances, piston 93 is pushed to the right-hand member of Fig. 1 b.
In Proportional valve 97, the skew pressure of second offset member 98 can freely be adjusted by the user.
The 4th oil circuit 8A of branch comes out from the first oil circuit 1A branch of branch, and extends to oil extraction road 21A, and oil passage control valve 8 then is installed on the 4th oil circuit 8A of branch.Oil passage control valve 8 has valve spring, and it closes oil circuit 8A under the normal condition, when it receives the signal that is predetermined, can open oil circuit 8A selectively.
In order to control the oil mass of control pump 2 outputs, the swash plate inclination angle of regulator 17 control control pumps 2.The work of regulator 17 is described identical with regulator 9 to main pump 1, therefore there is no need to describe again.
The work effect of hydraulic system of the present invention below will be described.
When hydraulic system was worked under neutral condition or no-load condition, the control valve of system was in its middle position, and the oil of pump 1 output makes the pressure of oil circuit 1A increase to the level that is predetermined that safety valve 15 is started working.That is, when oil passage control valve 8 is closed oil circuit 8A, when the 3rd oil circuit 3A of control member and the 4th oil circuit 4A of working portion close,, make pressure among the oil circuit 1A increase to the cracking pressure of safety valve then because the oil effect of pump 1 output.Under above-mentioned state, accumulator 7 storage pressure oils, isochronous governor 9 reduces the swash plate inclination angle of main pump 1, makes the oil mass of pump 1 output be decreased to minimum.In detail, because by the 1st oil circuit 9A and the second oil circuit 90A of branch, what feed that pressure oil in the loculus 91 of servo-cylinder 90 causes acts on pressure on piston 93 1 sides, than owing to act on the pressure on piston 93 opposite sides and the skew pressure height of first offset member 95 by what aperture 96 and the 3rd oil circuit 90B of branch flowed into that pressure oil in the big chamber 92 causes, therefore, piston 93 moves to the left end of Fig. 1 b.In this case, because the oil pressure of the 2nd oil circuit 90A of branch is than the skew pressure height of second offset member 98, therefore, Proportional valve 97 makes the 3rd oil circuit 90B of branch be communicated with oil extraction road 21A.Like this, Proportional valve 97 makes the pressure oil in big chamber 92, and proportional with the movement travel of piston 93 in the oil cylinder 90,21A flows back to fuel tank 21 by the oil extraction road.By regulating the skew pressure of offset member 98, can change the shift motion and the travelling speed of piston 93.
When oil passage control valve 8 was opened, oil extraction road 21A was communicated with the 4th oil circuit 8A of branch, and therefore, the oil of main pump 7 output is any one oil circuit by workpiece and control member not, and flows back to fuel tank 21.Even under above-mentioned state, because the effect of accumulator 7, the 1st oil circuit 1A still keeps desirable oil pressure.
When all working of system and actuating element start simultaneously, mainly be the pressure oil of having exported accumulator 7, oil passage control valve 8 is closed simultaneously, makes the oil of main pump 1 output be supplied to work and actuating element.Under above-mentioned state, the swash plate inclination angle of main pump 1 increases, and therefore, the oil mass of pump 1 output increases.That is, act on pilot pressure on the Proportional valve 97 when reducing when what the second oil circuit 90A of branch produced, the oil drain out of Proportional valve 97 is closed, and therefore, the pressure of the 3rd oil circuit 90B of branch increases.Under above-mentioned state, the pressure in the loculus 97 reduces, and like this, first offset member 95 makes piston 93 move to the right-hand member of Fig. 1 b, and the swash plate inclination angle of pump 1 increases again.
As mentioned above, the invention provides a kind of hydraulic system of power loader, it can reduce the oil mass of pump output selectively when neutral condition, thereby can save the output power and the working efficiency of improving loader of motor.Even this system also can keep the pressure in the oil circuit constant effectively under neutral condition, thereby has improved the response performance of loader.In addition, when neutral condition, this system allows the oil of pump output by bypass duct, main pump is worked under the load condition not having, and save the output power of pump.Therefore, system can prevent that pump is undesirable overheated, prolongs the expected life of pump and prevents oily temperature rise, thereby can prevent that service behaviour from reducing and the undesirable damage of actuator.
Though, for illustrative purposes, set forth the preferred embodiments of the present invention, but those of ordinary skills are to be understood that, under the situation that does not depart from the illustrated scope and spirit of the present invention of claims, can carry out various improvement, increase and alternative.
Claims (8)
1. the hydraulic system of a power loader, it comprises a ramp type main pump, is used for working portion and actuating element discharge pressure oil to system; With a ramp type control pump, be used for to control lever discharge pressure oil; The control valve output control signal that described control lever is described working portion; This hydraulic system also comprises:
A regulator, this regulator is installed on the first branch's oil circuit that comes from working connection branch that is extended out by each pump in main pump and the control pump, and described regulator is used for controlling selectively according to the change pressure of first branch's oil circuit the swash plate inclination angle of described main pump and each pump of control pump.
2. hydraulic system as claimed in claim 1 is characterized by, and described regulator comprises:
A servo-cylinder, it has:
A piston, this piston is contained in the described servo-cylinder and can moves, thereby the inside of described servo-cylinder is divided into loculus and big chamber, and the swash plate of each pump in described piston and main pump and the control pump is connected; With
An offset member, it is installed in the big chamber of servo-cylinder, and under normal circumstances, it pushes piston to loculus;
Second branch's oil circuit, it comes out from the first oil circuit branch of branch, leads to the servo-cylinder loculus;
The 3rd branch's oil circuit, it comes out from the first oil circuit branch of branch, leads to the big chamber of servo-cylinder;
One interconnects passage, and it extends out from first branch's oil circuit, and the second and the 3rd branch's oil circuit is connected;
An aperture, it is installed in described interconnecting on the passage, and is used for suppressing selectively the oil mass of the 3rd branch's oil circuit; With
A Proportional valve, it is installed in to extend out from the 3rd branch's oil circuit and leads on the oil circuit on oil extraction road, described Proportional valve is subjected to the skew effect of offset member, and can be according to the skew pressure of offset member and the oil pressure in second branch's oil circuit poor, allow the oil of the 3rd branch's oil circuit to discharge selectively by the oil extraction road.
3. hydraulic system as claimed in claim 2 is characterized by, and the skew pressure of described offset member is adjusted by the user.
4. hydraulic system as claimed in claim 1, it also comprises:
An accumulator, it is installed on the described working connection, is used for storing the unnecessary oil of main pump and each pump output of control pump; With
An one-way valve, it is installed on the working connection, and the position in main pump and the control pump between each pump and the described accumulator is used for preventing that the oil that stores from undesirably blowing back into each pump from accumulator.
5. hydraulic system as claimed in claim 1, it also comprises:
An oil passage control valve, it is installed in from working connection branch to come out to lead on the 4th branch's oil circuit on oil extraction road, described oil passage control valve is used for closing the 4th branch's oil circuit under the normal condition, and according to the signal that is predetermined, opens the 4th branch's oil circuit selectively.
6. the hydraulic system of a power loader, it comprises that one is given the working portion of system and ramp type main pump and ramp type control pump of giving control lever pressure oil output of actuating element pressure oil output; The control valve output control signal that described control lever is described working portion; This hydraulic system also comprises:
A regulator, it is installed on first branch's oil circuit that each pump extends out from main pump and control pump working connection branch comes, and described regulator is used for controlling selectively according to the change pressure of first branch's oil circuit the swash plate inclination angle of described main pump and each pump of control pump;
An accumulator, it is installed on the described working connection, is used for storing the unnecessary oil of main pump and each pump output of control pump;
An one-way valve, it is installed on the working connection, on the position in main pump and control pump between each pump and the described accumulator, is used for preventing that the oil that stores from undesirably blowing back into each pump from accumulator; With
An oil passage control valve, it is installed in from working connection branch, and leads on the 4th branch's oil circuit on oil extraction road, and described oil passage control valve is used under normal circumstances closing the 4th branch's oil circuit, and, open the 4th branch's oil circuit selectively according to the signal that is predetermined.
7. hydraulic system as claimed in claim 6 is characterized by, and described regulator comprises:
A servo-cylinder, it has:
A piston, it is installed in the described servo-cylinder and can moves, thereby the inside of described servo-cylinder is divided into loculus and big chamber, and described piston is connected with the swash plate of each pump in the control pump with main pump; With
An offset member, it is installed in the big chamber of servo-cylinder, and under the normal condition, it pushes piston to loculus;
Second branch's oil circuit, it comes out from the first oil circuit branch of branch, leads to the loculus of servo-cylinder;
The 3rd branch's oil circuit, it comes out from the first oil circuit branch of branch, leads to the big chamber of servo-cylinder;
One interconnects passage, and it extends out from first branch's oil circuit, and the second and the 3rd branch's oil circuit is linked together;
An aperture, it is installed in described interconnecting on the passage, is used in the oil mass that selectively suppresses the 3rd branch's oil circuit; With
A Proportional valve, it is installed in to extend out from the 3rd branch's oil circuit leads on the oil circuit on oil extraction road, described Proportional valve is subjected to the skew effect of offset member, and can be according to the skew pressure of offset member and the oil pressure in second branch's oil circuit poor, the oil of the 3rd branch's oil circuit is discharged by the oil extraction road.
8. hydraulic system as claimed in claim 7 is characterized by, and the skew pressure of described offset member is adjusted by the user.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| KR27837/96 | 1996-07-10 | ||
| KR1019960027837A KR100205568B1 (en) | 1996-07-10 | 1996-07-10 | Hydraulic device of loader |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN1170831A true CN1170831A (en) | 1998-01-21 |
Family
ID=19465927
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN97112245A Pending CN1170831A (en) | 1996-07-10 | 1997-07-10 | Hydraulic system for power loaders |
Country Status (5)
| Country | Link |
|---|---|
| JP (1) | JPH1082368A (en) |
| KR (1) | KR100205568B1 (en) |
| CN (1) | CN1170831A (en) |
| DE (1) | DE19729167A1 (en) |
| GB (1) | GB2315102A (en) |
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| CN100378343C (en) * | 2003-03-17 | 2008-04-02 | 日立建机株式会社 | Oil pressure circuit for working machines |
| CN102635144A (en) * | 2012-05-04 | 2012-08-15 | 山东理工大学 | Hydraulic system for loader |
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| CN102985704B (en) * | 2010-06-30 | 2015-09-09 | 沃尔沃建造设备有限公司 | For the control gear of construction plant oil hydraulic pump |
| CN102384115A (en) * | 2011-11-14 | 2012-03-21 | 上海电气液压气动有限公司 | Book pressing hydraulic device |
| CN103206421B (en) * | 2013-04-16 | 2015-08-12 | 三一重机有限公司 | Loader and hydraulic system thereof |
| KR102577950B1 (en) * | 2018-12-26 | 2023-09-14 | 웨이차이 파워 컴퍼니 리미티드 | Hydraulic variable pump sets and excavators |
| CN113757203B (en) * | 2021-09-13 | 2022-04-15 | 徐工集团工程机械股份有限公司科技分公司 | Loader electric control hydraulic system and loader |
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| DE3817218A1 (en) * | 1987-06-11 | 1988-12-22 | Mannesmann Ag | HYDRAULIC CONTROL SYSTEM FOR A HYDRAULIC EXCAVATOR |
| JPH04210101A (en) * | 1990-11-30 | 1992-07-31 | Komatsu Ltd | Oil-hydraulic circuit |
| EP0593782B1 (en) * | 1992-04-20 | 1998-07-01 | Hitachi Construction Machinery Co., Ltd. | Hydraulic circuit device for construction machines |
-
1996
- 1996-07-10 KR KR1019960027837A patent/KR100205568B1/en not_active IP Right Cessation
-
1997
- 1997-07-08 DE DE19729167A patent/DE19729167A1/en not_active Withdrawn
- 1997-07-10 CN CN97112245A patent/CN1170831A/en active Pending
- 1997-07-10 GB GB9714578A patent/GB2315102A/en not_active Withdrawn
- 1997-07-10 JP JP9200939A patent/JPH1082368A/en active Pending
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100378343C (en) * | 2003-03-17 | 2008-04-02 | 日立建机株式会社 | Oil pressure circuit for working machines |
| CN102635144A (en) * | 2012-05-04 | 2012-08-15 | 山东理工大学 | Hydraulic system for loader |
| CN102635144B (en) * | 2012-05-04 | 2014-06-11 | 山东理工大学 | Hydraulic system for loader |
Also Published As
| Publication number | Publication date |
|---|---|
| KR980009964A (en) | 1998-04-30 |
| JPH1082368A (en) | 1998-03-31 |
| KR100205568B1 (en) | 1999-07-01 |
| GB2315102A (en) | 1998-01-21 |
| DE19729167A1 (en) | 1998-01-15 |
| GB9714578D0 (en) | 1997-09-17 |
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| C06 | Publication | ||
| PB01 | Publication | ||
| C01 | Deemed withdrawal of patent application (patent law 1993) | ||
| WD01 | Invention patent application deemed withdrawn after publication |