CN103452961A - Open central control unit with constant and regulating pump - Google Patents
Open central control unit with constant and regulating pump Download PDFInfo
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- CN103452961A CN103452961A CN2013102055131A CN201310205513A CN103452961A CN 103452961 A CN103452961 A CN 103452961A CN 2013102055131 A CN2013102055131 A CN 2013102055131A CN 201310205513 A CN201310205513 A CN 201310205513A CN 103452961 A CN103452961 A CN 103452961A
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- control valve
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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
- F15B11/16—Servomotor systems without provision for follow-up action; Circuits therefor with two or more servomotors
- F15B11/17—Servomotor systems without provision for follow-up action; Circuits therefor with two or more servomotors using two or more pumps
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
- B62D—MOTOR VEHICLES; TRAILERS
- B62D5/00—Power-assisted or power-driven steering
- B62D5/06—Power-assisted or power-driven steering fluid, i.e. using a pressurised fluid for most or all the force required for steering a vehicle
- B62D5/065—Power-assisted or power-driven steering fluid, i.e. using a pressurised fluid for most or all the force required for steering a vehicle characterised by specially adapted means for varying pressurised fluid supply based on need, e.g. on-demand, variable assist
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
- B62D—MOTOR VEHICLES; TRAILERS
- B62D5/00—Power-assisted or power-driven steering
- B62D5/06—Power-assisted or power-driven steering fluid, i.e. using a pressurised fluid for most or all the force required for steering a vehicle
- B62D5/07—Supply of pressurised fluid for steering also supplying other consumers ; control thereof
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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
- E02F9/225—Control of steering, e.g. for hydraulic motors driving the vehicle tracks
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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
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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
- E02F9/2292—Systems with two or more 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
- E02F9/2296—Systems with a variable displacement pump
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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
- F15B2211/00—Circuits for servomotor systems
- F15B2211/20—Fluid pressure source, e.g. accumulator or variable axial piston pump
- F15B2211/205—Systems with pumps
- F15B2211/2053—Type of pump
- F15B2211/20538—Type of pump constant capacity
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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
- F15B2211/00—Circuits for servomotor systems
- F15B2211/20—Fluid pressure source, e.g. accumulator or variable axial piston pump
- F15B2211/205—Systems with pumps
- F15B2211/2053—Type of pump
- F15B2211/20546—Type of pump variable capacity
- F15B2211/20553—Type of pump variable capacity with pilot circuit, e.g. for controlling a swash plate
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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
- F15B2211/00—Circuits for servomotor systems
- F15B2211/20—Fluid pressure source, e.g. accumulator or variable axial piston pump
- F15B2211/205—Systems with pumps
- F15B2211/20576—Systems with pumps with multiple pumps
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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
- F15B2211/00—Circuits for servomotor systems
- F15B2211/30—Directional control
- F15B2211/31—Directional control characterised by the positions of the valve element
- F15B2211/3105—Neutral or centre positions
- F15B2211/3116—Neutral or centre positions the pump port being open in the centre position, e.g. so-called open centre
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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
- F15B2211/00—Circuits for servomotor systems
- F15B2211/40—Flow control
- F15B2211/405—Flow control characterised by the type of flow control means or valve
- F15B2211/40523—Flow control characterised by the type of flow control means or valve with flow dividers
- F15B2211/4053—Flow control characterised by the type of flow control means or valve with flow dividers using valves
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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
- F15B2211/00—Circuits for servomotor systems
- F15B2211/40—Flow control
- F15B2211/415—Flow control characterised by the connections of the flow control means in the circuit
- F15B2211/41554—Flow control characterised by the connections of the flow control means in the circuit being connected to a return line and a directional control valve
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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
- F15B2211/00—Circuits for servomotor systems
- F15B2211/40—Flow control
- F15B2211/42—Flow control characterised by the type of actuation
- F15B2211/428—Flow control characterised by the type of actuation actuated by fluid pressure
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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
- F15B2211/00—Circuits for servomotor systems
- F15B2211/40—Flow control
- F15B2211/45—Control of bleed-off flow, e.g. control of bypass flow to the return line
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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
- F15B2211/00—Circuits for servomotor systems
- F15B2211/50—Pressure control
- F15B2211/505—Pressure control characterised by the type of pressure control means
- F15B2211/50509—Pressure control characterised by the type of pressure control means the pressure control means controlling a pressure upstream of the pressure control means
- F15B2211/50536—Pressure control characterised by the type of pressure control means the pressure control means controlling a pressure upstream of the pressure control means using unloading valves controlling the supply pressure by diverting fluid to the return line
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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
- F15B2211/00—Circuits for servomotor systems
- F15B2211/70—Output members, e.g. hydraulic motors or cylinders or control therefor
- F15B2211/71—Multiple output members, e.g. multiple hydraulic motors or cylinders
- F15B2211/7142—Multiple output members, e.g. multiple hydraulic motors or cylinders the output members being arranged in multiple groups
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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
- F15B2211/00—Circuits for servomotor systems
- F15B2211/70—Output members, e.g. hydraulic motors or cylinders or control therefor
- F15B2211/78—Control of multiple output members
- F15B2211/781—Control of multiple output members one or more output members having priority
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- Engineering & Computer Science (AREA)
- General Engineering & Computer Science (AREA)
- Civil Engineering (AREA)
- Structural Engineering (AREA)
- Mining & Mineral Resources (AREA)
- Mechanical Engineering (AREA)
- Transportation (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Physics & Mathematics (AREA)
- Fluid Mechanics (AREA)
- Fluid-Pressure Circuits (AREA)
- Details And Applications Of Rotary Liquid Pumps (AREA)
- Rotary Pumps (AREA)
Abstract
The device (10) has a hydraulic steering device (20) that comprises a steering valve (21) which controls the flow of fluid. A pump (40) has an adjustable displacement volume which adjusts the displacement volume, such that one pump pressure (41) is controlled. A pump (50) has a constant displacement volume which promotes a hydraulic load (30) to other pump pressure (51). A delivery pressure regulator (42) has a shuttle valve (43) that is connected to a steering pressure (25) and other pump pressure, such that a pressure set-point is derived from the output pressure.
Description
Technical field
The present invention relates to a kind of control gear of the hydraulic pressure as described in the preamble according to claim 1.
Background technique
The control gear of this type of hydraulic pressure is for mobile working machine, particularly hydraulic shovel and wheel loader particularly with low cost.In the case, one or more parallel connected pumps are set, preferred external gear pump, it has constant extruding volume, and it can be transported to different consumers from a tank by pressurized fluid.As consumer, consider mobile working machine for example running driving device, digger arm oil hydraulic cylinder or for the steering gear of the direction of travel of regulating mobile working machine.In the case, described the steering gear is for security reasons in a kind of special status.Described the steering gear, particularly its switching valve, the consumer that must have precedence over other is supplied to pressurized fluid, thereby makes described mobile working machine under any circumstance can keep turning to.Therefore, a kind of pressure-gradient control valve of threeway pressure balance form is set, via this pressure-gradient control valve, pump and switching valve and at least one control valve is coupled together.Described pressure-gradient control valve so arranges, and preferentially described switching valve is supplied with to pressurized fluid.The motion utilization of other consumer is controlled with the control valve of open central configuration mode, and described control valve is comprehensive one-tenth one controll block preferably.Such controll block is special construct simply and so cost economy.
The shortcoming of the control gear of this hydraulic pressure is, when only having lower volume flow demand, by the constant conveying of pump, flows the energy that loss is very large, also needs higher hydrodynamic pressure simultaneously.This motion state for example occurs only having described the steering gear passive movement in following situation.
Summary of the invention
Task of the present invention is, improves the efficiency of the control gear of described hydraulic pressure in the mode of abnormal cost economy.
According to independent claims, this purpose solves in the following way, the first pump has adjustable extruding volume, wherein, the discharge pressure regulator is set, it can so regulate the extruding volume of described the first pump, the first pumping pressure utilized while being described the first pressure pump conveying is adjusted on pressure nominal value, wherein, described the second pump has constant extruding volume, wherein, described the second pump utilize the second pumping pressure only can be at least one other consumer carried, wherein, described discharge pressure regulator comprises selector valve, connect described steering pressure and described the second pumping pressure on described selector valve, wherein, derive described pressure nominal value from the outlet pressure of described selector valve.Correspondingly, except known the second pump with constant extruding volume, first pump with adjustable extruding volume also is set.Only to described other consumer, supply with pressurized fluid via described the second pump.Described the first pump is mainly used in supplying with described the steering gear and optimizes for this purpose aspect structure size.Therefore described the first pump is correspondingly less and be that cost is implemented economically.But described the first pump also can be supplied with pressurized fluid to other consumer, as long as the transmission capacity of these consumers is not used up by described the steering gear.For described the first pump is carried with required discharge pressure, the discharge pressure regulator of described the first pump not only is connected on described steering pressure and also is connected on described the second pumping pressure via selector valve.The outlet of selector valve is connected with the such entrance in its a plurality of entrances, on this entrance, is applied with the highest hydrodynamic pressure.
The special advantage of the solution of advising is, only adopts less and therefore the first pump of cost economy.This type of special efficiency of regulating pump is passed through the advised mode of connection just in time being utilized under some running statees like this, in energy loss described in these running statees, is king-sized.Therefore, improved the efficiency of total system in the mode of abnormal cost economy.In addition, for advised control gear, only adopt as lower member, these members have been produced in batches and therefore can have been purchased economically by cost.
Favourable improvement project of the present invention and improvement scheme have been provided in the dependent claims.
Described pressure-gradient control valve can be constructed as follows, the i.e. connection of the fluid from described the first pump to described switching valve is opened all the time, wherein, only have when the pressure of the pump side at described switching valve place has surpassed described steering pressure with a default preferential pressure difference, from the fluid connection of described the first pump other control valve at least one, just open, wherein, the outlet pressure that described pressure nominal value equals described selector valve adds that variable rated pressure is poor, wherein, the poor minimum value of described rated pressure is less than described preferential pressure difference.Should realize thus, when described other consumer is not operated, described the first pump is only carried to described the steering gear.Like this, described the first pump only delivery needle to described turn to required, have for turning to the fluid stream of required pressure.This so realizes, the pressure nominal value of described the first pump just so is conditioned, and makes described pressure-gradient control valve not decontrol and described other being connected of consumer.In the case, the poor minimum value of described rated pressure preferably is different from zero, thereby the inevitable Pressure Drop that described the first pumping pressure is deducted at described pressure-gradient control valve place obtains described steering pressure.When described other consumer is not operated, always regulate like this.When described other consumer and described the steering gear while not being operated, the extruding volume of described the first pump is adjusted to zero, and wherein, by described rated pressure, poor minimum value is adjusted to the first pumping pressure.Poor preferred two the different values that only have of described variable rated pressure, i.e. aforesaid minimum value and the maximum value the following describes.
If described the steering gear passive movement, the steering pressure interface of described switching valve can with described the steering gear in pressure couple together, wherein, if described the steering gear is passive movement not, described steering pressure interface is connected with described tank, wherein, if not only described steering pressure and also described the second pumping pressure different from the pressure in described tank, on the poor value be raised to higher than described preferential pressure difference of described rated pressure.Realized thus, once described other consumer is operated, described the first pump also can be carried to described other consumer.This so realizes, improves described pressure nominal value, until described pressure-gradient control valve is decontroled and being connected of described control valve.In the case, distinguish two kinds of situations.If described the second pumping pressure is greater than described steering pressure, in any case described pressure-gradient control valve is opened, because described pressure nominal value all is greater than described the second pumping pressure and therefore is greater than described steering pressure in each situation.If described the second pumping pressure is less than described steering pressure, the mode of connection advised is far reaching.Here must initiatively improve described pressure nominal value, thereby described pressure-gradient control valve is decontroled and described other being connected of consumer.Only have the pressure difference of working as with described tank to surpass default little threshold value, described threshold value can be for example 5bar, preferably just adopts a kind of pressure different from the pressure in described tank.This threshold value is preferably so selected, and it is greater than the idling pressure of described the second pump.
Described discharge pressure regulator can comprise two pressure valves, at described two pressure valve places, connects described steering pressure and described the second pumping pressure, wherein, utilizes the outlet pressure of described two pressure valves, poor in order to improve described rated pressure.In the situation that two known pressure valves, it also is known as the selector valve of reversion, and its outlet is connected with the such entrance in its a plurality of entrances, in this ingress, is applied with minimum pressure.Can cause the poor raising of rated pressure that advise above, described in simple mode by two pressure valves of using this type of.
Described the second pumping pressure can be connected on described discharge pressure regulator via spring-loaded pump safety check, only has and surpassed defaultly while opening pressure difference when described the second pumping pressure, and described discharge pressure regulator is just opened.Described the second pump is with the constant extruding volume volume flow of delivered constant all the time, and described volume flow flows and causes there Pressure Drop through the circulation canal of the control valve set.Therefore, only have when other consumer is not operated, described the second pumping pressure is only and is different from zero.Like this, described the second pumping pressure is for example 3bar.In the situation that definite described pressure nominal value is not considered, described pump safety check is set for described idling pressure.As long as described the second pump is only carried with described idling pressure, described pump safety check cuts out.Therefore described the second pumping pressure interrupted with being connected of described discharge pressure regulator.
A plurality of other consumers can be set, wherein, each control valve has a circulation canal, when the fluid with the consumer set is connected cut-off, described circulation canal is opened, and wherein, the circulation canal of all control valves is connected, wherein, described the first pump is connected with described tank with the circulation canal of described the second pump via described series connection.Described circulation canal is opened in the neutral position of opening of known open central configuration mode.Once will make consumer motion, open constantly and being connected of described consumer, wherein, close constantly described circulation canal simultaneously.Therefore the constant conveying stream of described the second pump is divided on described circulation canal and described consumer, thereby can makes described consumer with variable speed motion.
The circulating pressure scale can be set, via described circulating pressure scale, the circulation canal of described circulation canal or described series connection and described tank are coupled together, wherein, while having only had pressure when the control valve side at described circulating pressure scale place to be greater than to be subtracted poor the second pumping pressure of circulating pressure, just open described circulating pressure scale.Therefore should realize, when in described other consumer one is operated, described the second pumping pressure improves immediately.Improve thus the exact controllability of described control valve, wherein, particularly started in advance described accurate control behavior.Particularly no longer need to, before the consumer motion set starts, just described control valve be opened with an Invalid path (Totweg).
Described circulating pressure is poor can be the pressure difference of opening of described pump safety check.When adopting described circulating pressure scale, it is poor that the idling pressure of described the second pump equals described circulating pressure.Correspondingly,, describedly open pressure difference to equal described circulating pressure poor in the situation that determine when the pressure nominal value of described the first pump should not be considered when described idling pressure.
The pumping pressure scale can be set, via described pumping pressure scale, described the second pump can be transported in described tank, wherein, described pumping pressure scale is connected on described pressure-gradient control valve as follows, be that the pressure that described the first pump utilizes when at least one control valve is carried can be opened described pumping pressure scale, wherein, described pumping pressure scale is closed in all the other situations.In the situation that described control gear, described the first pump designs for little volume flow and high pressure, and wherein, described the second pump designs for little pressure and large volume flow.Pass through advised connection and realized, when the maximum delivery pressure of described the second pump no longer is enough to operate described other consumer, described the first pump can be carried to described other consumer.The triggering pressure of described pumping pressure scale is correspondingly determined by the maximum delivery pressure of described the second pump.Once described the first pumping pressure has surpassed described triggering pressure, be transported in described tank the essentially no pressure of described the second pump, wherein, described other consumer is only also supplied with via described the first pump.Obviously, although described other consumer only can also be with less speed motion with larger power under this running state.
Described at least one control valve can be connected with described the second pump with described the first pump via safety check respectively, and its mode is that described pressurized fluid only can flow at least one control valve from the pump set.Should prevent thus, described the first pump and described the second pump are used as motor and move.Be necessary for two pumps for this reason and set respectively the safety check of opening in a minute.
The accompanying drawing explanation
Below the present invention by means of the exemplary detailed explaination of accompanying drawing.Wherein:
Fig. 1 shows the wiring diagram according to the first mode of execution of the control gear of hydraulic pressure of the present invention;
Fig. 2 shows the intercepting part of an amplification in the zone of described discharge pressure regulator, Fig. 1; And
Fig. 3 shows the wiring diagram according to the second mode of execution of the control gear of hydraulic pressure of the present invention.
Embodiment
Fig. 1 shows the wiring diagram according to the first mode of execution of the control gear of hydraulic pressure of the present invention.Described control gear 10 comprises for the steering gear 20 of mobile working machine and a plurality of other consumer 30.The direction of travel of described the steering gear for regulating described mobile working machine.Described other consumer 30 can be running driving device or the oil hydraulic cylinder on the cantilever of described mobile working machine of for example described mobile working machine.
Described the steering gear 20 is diverted valve 21 operation, and described switching valve for example can be according to Bosch Rexroth AG(Bosch Rexroth Corp.) catalogue " Lenkaggregat Typ LAGC(steering box set type LAGC) " (job number RD 14365; In October, 2007 version) structure.Described switching valve 21 has two interfaces 26, for connecting (unshowned) steering cylinder, utilizes described steering cylinder to make described the steering gear motion.Pump 27, tank 28 and steering pressure interface 22 also are set.Described pump interface 27 is connected on described pressure-gradient control valve 23, and wherein, described tank interface 28 is connected on described tank 11.When described switching valve 21 is not operated, described steering pressure interface 22 is connected with described tank interface 28.When described switching valve 21 is operated, at described steering pressure interface 22 places, be applied with pressure at interface 26 places as steering pressure 25, at described jointing, pressurized fluid flows to described steering cylinder.
Described pressure-gradient control valve 23 can be for example according to Bosch Rexroth AG(Bosch Rexroth Corp.) catalogue " Priorit tsventil Typ LPS(pressure-gradient control valve type LPS) " (job number RD 27548; 2006 06 month version) construct.Described pressure-gradient control valve 23 is threeway pressure balances, and entrance and one first is exported for it and one second outlet couples together.Described the first outlet is connected on the pump interface 27 of described switching valve 21, and wherein, described the second interface is connected on other the control valve 31 of consumer 30.The spool of described pressure-gradient control valve 23 is pressed in primary importance by spring 24, and in this primary importance, the entrance be connected on described the first pump 40 is connected with described the first outlet, and wherein, described the second outlet ends.Spring side at described spool is applied with described steering pressure 25, wherein, at the spring offside, is applied with the pressure in the first outlet port of described spool.The pretightening force of described spring 24 obtains described preferential pressure difference, and it for example is adjusted to 10bar.Once the pressure in described the first outlet port is greater than described steering pressure 25 with described preferential pressure difference, described spool moves to the direction of the described second place all the time.In the case, open all the time being connected of exporting with described second, wherein, with being connected of described the first outlet, omited micro-throttling.Still still open in the case, with in the end position that is connected to the described second place of the first outlet.
Described consumer 30 is equipped with respectively the control valve 31 in open central configuration mode.In the case, also a plurality of consumers 30 can be connected on a control valve 31.Described control valve 31 is comprehensively become a valve piece, and described valve piece is for example according to Bosch Rexroth AG(Bosch Rexroth Corp.) catalogue " Mitteldruck-Mobilsteuerblock Typ Ml-16 und 32(intermediate pressure-mobile controll block type Ml-16 and 32) " (job number RD 64 263; 1998 02 month version) implement.Described control valve 31 has circulation canal 32, and wherein, described circulation canal 32 is together in series all control valves.The second outlet of described pressure-gradient control valve 23 is connected with the circulation canal of the first control valve 31 of described cascaded structure via safety check 12a.Described the second pump is connected on identical point via safety check 12b.Described safety check 12a; 12b so installs, and makes the pressurized fluid only can be from the pump 40 set; 50 flow to described control valve 31.
As long as described control valve 31 is arranged in neutral position, with being connected of consumer 30 set, end, wherein, described circulation canal 32 is opened fully.Once described control valve 31 is operated, described circulation canal 32 is continued to close, and simultaneously, is continued to open to the connection of the consumer 30 set, and its mode is that the fluid stream of inflow is divided on two flow paths.Therefore the movement velocity that can infinitely regulate the described consumer set 30.Described control valve 31 has two direction of operating, thus the moving direction that also can regulate the described consumer set 30.In the case, the pressurized fluid refluxed from described consumer 30 flows out to described tank 11 via the tank interface 34 separated of described valve piece.
End at the cascaded structure of described circulation canal 32, be arranged in such a way circulating pressure scale 33, makes described circulating pressure scale to be opened to described tank 11 by the pressure in described circulation canal 32.Along closing direction, described circulating pressure scale is connected on the second pumping pressure 51 via pump safety check 52, and described the second pump 50 utilizes described the second pumping pressure to be carried.Described pump safety check 52 is kept cutting out by spring, and wherein, described pump safety check can be opened by described the second pumping pressure 51.Described pump safety check 52 open pressure difference in other words the pretightening force of corresponding spring so regulate, when described the second pump moves in idle running, that is to say when the consumer 30 that there is no other is operated, described open pressure difference in other words described pretightening force be positioned on described the second pumping pressure 51.In the case, for example adjust the pressure difference of opening of 5bar.Under this state, described circulating pressure scale 33 is not loaded by described the first pumping pressure 51.An once passive movement in other consumer 30, described pump safety check 52 is opened, and described the second pumping pressure 51 is in the situation that be subtracted the described pressure difference of opening and be applied on described circulating pressure scale 33, described selector valve 43 and described two pressure valves 44.Result is that when control valve 31 is operated, described the second pumping pressure 51 raises immediately, until consumer 30 motions that set.
Described the second pump 50 has constant extruding volume and is preferably configured as external gear pump.Described the second pump is only carried pressure-bearing liquid and do not carry to described the steering gear 20 to described other consumer 30 from tank 11.Pressure interface place at described the second pump 50 connects pumping pressure scale 53, and described pumping pressure scale is pressed in the position of closing by spring.The pressure that connects the second outlet port of described pressure-gradient control valve 23 at the spring offside.Once described pressure has surpassed the pressure equivalence of the spring of described pumping pressure scale 53, described pumping pressure scale open and described the second pump 50 essentially no pressure be transported in described tank 11.Result is, only also has described the first pump 40 that pressurized fluid is carried to described other consumer 30, but this conveying carries out with extra high pressure, and described pressure may surpass the maximum delivery pressure of described the second pump 50.
Fig. 2 shows the intercepting part of an amplification in the zone of described discharge pressure regulator 42, Fig. 1, wherein, for clarity, has removed described the second pump 50.Described the first pump 40 sucking-off pressurized fluid and it is carried to described pressure-gradient control valve (label 23 in Fig. 1) with the first pumping pressure 41 from described tank 11.Described the first pump 40 has the extruding volume of sustainable adjusting and is preferably implemented as swash plate operated pump or the inclined shaft pump.Cylinder 60 is regulated in described extruding volume utilization and kicker cylinder 61 is regulated, and described adjusting cylinder and described kicker cylinder are configured to respectively simple single cylinder.Described kicker cylinder 61 is connected on described the first pumping pressure 41 and causes the increase of described extruding volume.Result is that, once described the first pump is placed in rotational motion by (unshowned) motor or internal-combustion engine, described the first pump is regulated towards the direction of maximum extruding volume.Described kicker cylinder 61 is provided with spring, and described spring rolls described kicker cylinder away from equally.Even therefore described the first pump 40 does not rotate, also adjust the extruding volume of described maximum.
Described adjusting cylinder 60 has the opposite effect with described kicker cylinder 61 and therefore causes reducing of described extruding volume.Described adjusting cylinder is regulated pressure balance 62 by the first adjusting pressure balance and second; 64 activate.Be pressed in primary importance by the spring 63 of preferred manual tune but described first regulates pressure balance 62, be connected with described tank 11 and with described the second adjusting pressure balance 64 at the cylinder 60 of adjusting described in this primary importance.At described spring offside, described the first pumping pressure 41 is applied to described first and regulates on pressure balance 62, thereby can regulate pressure balance 62 by described first, moves in the second place, and in this second place, described adjusting cylinder 60 is connected with described the first pumping pressure 41.Therefore, when described the first pumping pressure 41 has surpassed the pressure equivalent time in described spring 63 adjusted, described the first pump is regulated towards the direction of little extruding volume.Therefore, described first regulate the restriction made progress that pressure balance 62 has caused described the first discharge pressure 41.
Described second regulates pressure balance 64 is pressed in primary importance by spring 65, regulates pressure balance 62 at the cylinder 60 of adjusting described in this primary importance via described first and is connected with described tank 11.There is described the first pumping pressure 41 at the described second spring offside of regulating pressure balance 64, move in the second place thereby can regulate pressure balance by described second, regulate pressure balance 62 at the cylinder 60 of adjusting described in this second place via described first and be connected with described the first pumping pressure 41.Described spring 65 is designed with spring regulating device 66, and described spring regulating device can the predefined value with for example 4bar be improved the pretightening force of described spring 65.Described spring regulating device 66 is via described two pressure valves 44 operations, wherein, when the pressure in the outlet port of described two pressure valves 44 has surpassed the pressure in described tank 11 with the little threshold value of presetting, the raising of described pretightening force occurs.
In addition, the described second spring side of regulating pressure balance 64 is connected to the outlet port of described selector valve 43.In addition, regulating spring 65 on pressure balance 64 described second preferably can manual tune, wherein, for example adjusts the pressure equivalence of 8bar.Therefore, the pressure nominal value gone out in described the second adjusting pressure balance 64 adjusted is that the pressure in the outlet port of described selector valve 43 adds that rated pressure is poor.The poor minimum value of described rated pressure is the pressure equivalence gone out in described spring 65 adjusted, for example 8bar.Described rated pressure is poor can bring up to 12bar from for example 4bar by described spring regulating device 66.Therefore, described rated pressure is poor quickly lower than described preferential pressure difference and, quickly again higher than described preferential pressure difference, described preferential pressure difference is for example 10bar.This depends on, whether the lower pressure applied in two ingress of described two pressure valves 44 is higher than the pressure in described tank 11.Be applied with described steering pressure 25 and the second pumping pressure of opening pressure difference that has been subtracted pump safety check 52 on described two pressure valves 44.Therefore, only have at least one (label 30 in Fig. 1) in described the steering gear (label 20 in Fig. 1) and described other consumer all during passive movement, the poor raising of described rated pressure just occurs.Be applied with equally described two pressure in the ingress of described selector valve 43, wherein, be applied with the higher pressure in described two pressure in the outlet port of described selector valve 43 and be applied to the described second spring side of regulating pressure balance 64.
Fig. 3 shows the wiring diagram according to the second mode of execution of the control gear 10 of hydraulic pressure of the present invention.Described the second mode of execution is constructed in the same manner with the first mode of execution except the difference of describing hereinafter, therefore can be with reference to the mode of execution of Fig. 1 and 2 with regard to this respect.In the case, identical parts mean with identical reference character.
In the situation that the second mode of execution for clarity, has been removed described circulating pressure scale and described pumping pressure scale.But described parts also can easily supplement into, in order to obtain the described advantage of described reference the first mode of execution.
The main distinction of the first mode of execution and the second mode of execution is mode and the method for the pressure nominal value of definite described the first pump 40.In the case, regulate pressure balance 64 described second and get on except described spring regulating device (in Fig. 2, label 66), thereby the assembly be comprised of with discharge pressure regulator 42 described the first pump 40 is consistent with the structural regime provided on market in batches.Described pressure nominal value only adds that by being applied to the described second pressure of regulating the spring side of pressure balance 64 the pressure equivalence of for example 8bar gone out in described spring adjusted draws.So-called pressure equivalence is also the poor minimum value of described rated pressure.
At the described second pressure of regulating the spring side of pressure balance 64, be the pressure in the outlet port of selector valve 43, this selector valve comprises three safety check that separate.Therefore described selector valve comprises three entrances, wherein, is applied with the highest pressure of described three ingress in outlet port.One in described entrance is connected with described steering pressure 25.Another entrance is connected with described the second pumping pressure 51.The 3rd entrance is connected with rated pressure scale 68.Described rated pressure scale 68 is pressed into by spring in the position of closing, and wherein, the spring side also is applied with described steering pressure 25.Described spring for example is tightened on the pressure equivalence of 4bar in advance.Be applied with the pressure between described rated pressure scale 68 and described selector valve 43 at the spring offside.Therefore, described rated pressure scale 68 can be adjusted to this pressure on a value, and this value exceeds that the pressure of the spring that the size of described steering pressure 25 is described rated pressure scale is equivalent, for example 4bar.But its prerequisite is, described two position two-way valve 67 is to be linked in the position of opening, and wherein, described rating value pressure balance 68 is connected with described the first pumping pressure 41 via described two position two-way valve.But described two position two-way valve 67 is pressed in the state of closing by spring.Connect the outlet of described two pressure valves 44 at described spring offside, connect described steering pressure 25 and described the second pumping pressure 51 in the ingress of described two pressure valves.When one of described the steering gear 20 and described control valve 31 all are operated, described two position two-way valve 67 is linked in the position of opening.
The safety check 52 that is noted that described selector valve 43 is provided with return spring, and wherein said safety check sets to described the second pumping pressure 51, only has when described the second pumping pressure 51 has surpassed idling pressure, and described safety check is just opened.Described return spring for example is tightened on the pressure equivalence of 5bar in advance.Therefore, described safety check 52 also has the function according to the pump safety check of the first mode of execution of Fig. 1 and 2.
reference numerals list
The control gear of 10 hydraulic pressure
11 tanks
The 12a safety check
The 12b safety check
20 the steering gears
21 switching valves
22 steering pressure interfaces
23 pressure-gradient control valves
The spring of 24 pressure-gradient control valves
25 steering pressures
26 interfaces for steering cylinder
27 pump interfaces
28 tank interfaces
30 consumers
31 control valves
32 circulation canals
33 circulating pressure scales
The tank interface of 34 valve pieces
40 first pumps
41 first pumping pressures
42 discharge pressure regulators
44 2 pressure valves
50 second pumps
51 second pumping pressures
52 pump safety check
53 pumping pressure scales
60 regulate cylinder
61 kicker cylinders
62 first regulate pressure balance
63 first regulate the spring of pressure balance
64 second regulate pressure balance
65 second regulate the spring of pressure balance
66 spring regulating devices
67 two position two-way valves
68 rating value pressure balances
Claims (10)
1. for the control gear (10) of the hydraulic pressure of mobile working machine, described control gear has other the consumer (30) of hydraulic pressure of the steering gear (20) of the hydraulic pressure for regulating direction of travel and at least one,
Wherein, described control gear comprises the first pump and the second pump (40 separated with the first pump; 50), described the first pump and described the second pump can be by hydraulic fluid from tank (11) to described the steering gear (10) and/or described at least one consumer (30) carry,
Wherein, described the steering gear (20) is equipped with switching valve (21), and described switching valve can be controlled the fluid stream of going to described the steering gear (20), wherein, described switching valve (21) has steering pressure interface (22), at described steering pressure jointing, is applied with steering pressure (25)
Wherein, each other consumer (30) is equipped with the control valve (31) in open central configuration mode, and described control valve can be controlled the fluid stream of going to the consumer (30) set,
Wherein, the pressure-gradient control valve (23) of threeway pressure balance form is set, via described pressure-gradient control valve, described the first pump (40) and described switching valve (21) and described at least one control valve (31) is coupled together,
It is characterized in that, described the first pump (40) has the extruding volume that can regulate, wherein, discharge pressure regulator (42) is set, described discharge pressure regulator can so be regulated the extruding volume of described the first pump (40), that is the first pumping pressure (41) utilized while, described the first pump (40) being carried is adjusted on pressure nominal value
Wherein, described the second pump (50) has constant extruding volume, and wherein, described the second pump utilizes the second pumping pressure (51) only can be carried to described at least one other consumer (30),
Wherein, described discharge pressure regulator (42) comprises selector valve (43), connect described steering pressure (25) and described the second pumping pressure (51) on described selector valve, wherein, derive described pressure nominal value from the outlet pressure of described selector valve (43).
2. according to the control gear of hydraulic pressure claimed in claim 1, it is characterized in that, described pressure-gradient control valve (23) can be constructed as follows, the i.e. connection of the fluid from described the first pump (40) to described switching valve (21) is opened all the time, wherein, when the pressure that only has the pump side of locating when described switching valve (21) has surpassed described steering pressure (25) with a default preferential pressure difference, from the fluid connection of described the first pump (40) other control valve (31) at least one, just open, wherein, the outlet pressure that described pressure nominal value equals described selector valve (43) adds that variable rated pressure is poor, wherein, the poor minimum value of described rated pressure is less than described preferential pressure difference.
3. according to the control gear of hydraulic pressure claimed in claim 2, it is characterized in that, when described the steering gear passive movement, the steering pressure interface (22) of described switching valve (21) is connected with the pressure in described the steering gear (20), wherein, when described the steering gear (20) not during passive movement, described steering pressure interface (22) is connected with described tank (11), wherein, when described steering pressure (25) and described the second pumping pressure (51) are all different from the pressure in described tank (11), by on the poor value of bringing up to higher than described preferential pressure difference of described rated pressure.
4. according to the control gear of hydraulic pressure claimed in claim 3, it is characterized in that, described discharge pressure regulator (42) comprises two pressure valves (44), connect described steering pressure (25) and described the second pumping pressure (51) at described two pressure valve places, wherein, utilize the outlet pressure of described two pressure valves (44), poor in order to improve described rated pressure.
5. according to the control gear of hydraulic pressure in any one of the preceding claims wherein, it is characterized in that, described the second pumping pressure (51) is connected on described discharge pressure regulator (42) via spring-loaded pump safety check (52), only have and surpassed defaultly while opening pressure difference when described the second pumping pressure (51), described discharge pressure regulator just opens.
6. according to the control gear of hydraulic pressure in any one of the preceding claims wherein, it is characterized in that, a plurality of other consumers (30) are set, and wherein, each control valve (31) has a circulation canal (32), when the fluid of the consumer with setting (30) is connected cut-off, described circulation canal is opened, and wherein, the circulation canal (32) of all control valves (31) is connected, wherein, described the first pump and described the second pump (40; 50) circulation canal (32) via described series connection is connected with described tank (11).
7. according to the control gear of hydraulic pressure in any one of the preceding claims wherein, it is characterized in that, circulating pressure scale (33) can be set, via described circulating pressure scale, the circulation canal (32) of described circulation canal (32) described series connection in other words and described tank (11) are coupled together, wherein, while having only had the pressure of the control valve side of locating when described circulating pressure scale (33) to be greater than to be subtracted poor the second pumping pressure (51) of circulating pressure, just open described circulating pressure scale (33).
8. according to the control gear of hydraulic pressure claimed in claim 7, quote claim 5, it is characterized in that, described circulating pressure is poor is the pressure difference of opening of described pump safety check (52).
9. according to the control gear of hydraulic pressure in any one of the preceding claims wherein, it is characterized in that, pumping pressure scale (53) can be set, via described pumping pressure scale, described the second pump (50) can be transported in described tank (11), wherein, described pumping pressure scale (53) is connected on described pressure-gradient control valve (23) as follows, be that the pressure that described the first pump (40) utilizes when at least one control valve (31) is carried can be opened described pumping pressure scale (53), wherein, described pumping pressure scale is closed in all the other situations.
10. according to the control gear of hydraulic pressure in any one of the preceding claims wherein, it is characterized in that, described at least one control valve (31) can be respectively via safety check (12a; 12b) with described the first pump and described the second pump (40; 50) connect, its mode is that described pressurized fluid only can be from the pump (40 set; 50) at least one control valve (31), flow.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE102012208938.1 | 2012-05-29 | ||
| DE201210208938 DE102012208938A1 (en) | 2012-05-29 | 2012-05-29 | Hydraulic control device for mobile working machine e.g. hydraulic excavators, has delivery pressure regulator that includes shuttle valve connected to steering pressure and pump pressure, such that pressure set-point is derived |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN103452961A true CN103452961A (en) | 2013-12-18 |
| CN103452961B CN103452961B (en) | 2017-04-19 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201310205513.1A Expired - Fee Related CN103452961B (en) | 2012-05-29 | 2013-05-29 | Open central control unit with constant and regulating pump |
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| Country | Link |
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| CN (1) | CN103452961B (en) |
| DE (1) | DE102012208938A1 (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE102014226182A1 (en) | 2014-12-17 | 2016-06-23 | Robert Bosch Gmbh | Control valve assembly and hydraulic drive system with it |
| DE102015212186A1 (en) * | 2015-06-30 | 2017-01-05 | Zf Friedrichshafen Ag | Device for supplying hydraulic consumers |
| DE102015216737A1 (en) | 2015-09-02 | 2017-03-02 | Robert Bosch Gmbh | Hydraulic control device for two pumps and several actuators |
| DE102016215747A1 (en) | 2016-08-23 | 2018-03-01 | Robert Bosch Gmbh | Valve arrangement for a first and a second pump |
| DE102017109421A1 (en) * | 2017-05-03 | 2018-11-08 | Claas Tractor Sas | Hydraulic system of a agricultural or construction industry usable machine |
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| CN1989039A (en) * | 2004-07-28 | 2007-06-27 | 沃尔沃建造设备控股（瑞典）有限公司 | Hydraulic system and work machine comprising such a system |
| EP1837528A1 (en) * | 2004-12-21 | 2007-09-26 | Yanmar Co., Ltd. | Hydraulic circuit |
| CN201568386U (en) * | 2009-05-21 | 2010-09-01 | 北京海纳创为液压系统技术有限公司 | Wheeled vehicle hydraulic auxiliary driving system |
| CN201581431U (en) * | 2009-12-18 | 2010-09-15 | 广西柳工机械股份有限公司 | Loader load sensitization hydraulic device |
| US20110289908A1 (en) * | 2010-05-28 | 2011-12-01 | Johnson Bryan A | Hydraulic system having implement and steering flow sharing |
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| US4044786A (en) * | 1976-07-26 | 1977-08-30 | Eaton Corporation | Load sensing steering system with dual power source |
| DE4108915C2 (en) * | 1991-03-19 | 2002-08-01 | Bosch Gmbh Robert | Hydraulic device for supplying pressure medium to a privileged primary load circuit |
| DE19531413B4 (en) * | 1995-08-26 | 2007-09-20 | Bosch Rexroth Aktiengesellschaft | Arrangement for supplying the hydraulic steering of a motor vehicle |
| DE102009021104A1 (en) * | 2009-05-13 | 2010-11-18 | Hydac Filtertechnik Gmbh | Hydraulic system |
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2012
- 2012-05-29 DE DE201210208938 patent/DE102012208938A1/en not_active Withdrawn
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| Publication number | Priority date | Publication date | Assignee | Title |
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| US20010008068A1 (en) * | 1997-11-21 | 2001-07-19 | Komatsu Ltd. | Hydraulic circuit for working vehicle |
| JP2000337306A (en) * | 1999-03-24 | 2000-12-05 | Kayaba Ind Co Ltd | Control circuit |
| CN1989039A (en) * | 2004-07-28 | 2007-06-27 | 沃尔沃建造设备控股（瑞典）有限公司 | Hydraulic system and work machine comprising such a system |
| EP1837528A1 (en) * | 2004-12-21 | 2007-09-26 | Yanmar Co., Ltd. | Hydraulic circuit |
| CN201568386U (en) * | 2009-05-21 | 2010-09-01 | 北京海纳创为液压系统技术有限公司 | Wheeled vehicle hydraulic auxiliary driving system |
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| US20110289908A1 (en) * | 2010-05-28 | 2011-12-01 | Johnson Bryan A | Hydraulic system having implement and steering flow sharing |
Also Published As
| Publication number | Publication date |
|---|---|
| DE102012208938A1 (en) | 2013-12-05 |
| CN103452961B (en) | 2017-04-19 |
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