KR101470626B1 - Electric oil pressure system of construction equipment - Google Patents

Abstract

The present invention relates to an electrohydraulic system of a construction equipment, and more particularly to a hydraulic pump for a hydraulic pump, which is capable of varying the discharge flow rate of hydraulic fluid, comprising first and second pumps for supplying hydraulic oil to first and second actuator groups The first hydraulic line in which the discharged hydraulic fluid is moved to the first actuator group, the second hydraulic line in which the hydraulic fluid discharged from the second pump is moved to the second actuator group, and the hydraulic fluid in the first hydraulic line and the second hydraulic line join A regeneration circuit which is provided in a control valve for controlling the hydraulic fluid provided by the actuator and supplies a part of the hydraulic fluid to the actuator using regenerative energy or inertial energy generated by the drive of the actuator, An actuator use flow rate calculation section for calculating a regeneration flow rate Qregen supplied from the regeneration circuit section to the actuator, Calculates the flow rate Qscump currently being used and the flow rate Qpump to be discharged from the first and second pumps by subtracting the regeneration flow rate Qregen from the required flow rate Qset input by the joystick operation, And a swash plate control part for calculating a swash plate angle of the pump so that the combined oil flow rate is added to the flow rate Qpump to be discharged and the hydraulic oil is discharged by the added or subtracted result value, And an electronic proportional pressure reducing valve driver for controlling the swash plate angles of the first and second pumps.

Construction machinery, construction equipment, hydraulic circuit, hydraulic system, hydraulic oil, redistribution

Description

ELECTRIC OIL PRESSURE SYSTEM OF CONSTRUCTION EQUIPMENT < RTI ID = 0.0 >

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electromagnetic hydraulic system of a construction equipment, and more particularly, to an electromagnetic hydraulic system of a construction equipment capable of operating an electronic joystick or a remote controller to supply an appropriate amount of flow and hydraulic pressure required by an actuator of a construction equipment will be.

Generally, the construction equipment includes a pump that generates hydraulic pressure by using the power of the engine and the engine, a controller that controls the hydraulic pressure generated by the pump by the hydraulic valve, and an actuator that works by the hydraulic pressure.

In particular, the construction equipment as described above operates the respective actuators and the like by controlling the flow rate and the hydraulic pressure by the hydraulic control system, and for example, the actuators include a boom, an arm, a bucket, a swing, , The left travel (Travel left), and the right travel (Travel right).

Further, the pump is provided with a plurality of pumps, and one of the pumps is responsible for driving the left travel, the swing and the arm of the actuator, and the other pump is for driving the right travel, the boom and the bucket among the actuators described above.

However, the conventional hydraulic control system described above has the following problems.

During traveling, the actuator for the left traveling and the actuator for the right traveling are driven to move forward or backward of the construction equipment.

On the other hand, the boom, the arm, the bucket, or the swing can be driven while traveling, and when the separate actuator independent of the traveling is driven, the pump for the actuator is overloaded or the left traveling actuator or the right traveling actuator There is a problem that the operating oil is biased to the running actuator and the straightness of the construction equipment can not be guaranteed.

That is, there is a problem in that the safe operation of the construction equipment can not be guaranteed when the use of the hydraulic oil discharged from the other pump is biased rather than the use of the hydraulic oil discharged from any one pump among the plurality of pumps.

On the other hand, in the conventional hydraulic control system, there is a problem that the flow rate used in each of the actuators can not be accurately predicted or grasped, thereby causing the engine and the pump to operate excessively in order to be sufficiently used in each of the actuators .

In addition, excessive operation of the engine and the pump resulted in a reduction in the fuel consumption of the construction equipment and a serious waste of energy.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a hydraulic pump capable of compensating for biased hydraulic oil by changing the hydraulic circuit when the use of hydraulic oil discharged from one pump is biased rather than the use of hydraulic oil discharged from one pump among a plurality of pumps And to provide an electronic hydraulic system of a construction equipment capable of ensuring safe operation of construction equipment.

The present invention has been made in view of the above problems, and it is an object of the present invention to at least partially solve the problems in the conventional arts. There will be.

According to an aspect of the present invention, there is provided an electromagnetic hydraulic system for a construction equipment, the hydraulic fluid supply system comprising: a hydraulic pump for supplying hydraulic fluid to a first and second actuator groups connected to each other for driving a working device, First and second pumps 70a and 70b; A first hydraulic line 91 in which the hydraulic fluid discharged from the first pump 70a is transferred to the first actuator group; A second hydraulic line (97) through which the hydraulic fluid discharged from the second pump (70b) is transferred to the second actuator group; A direction switching valve (80) for switching the direction in which the working fluid of the first hydraulic line (91) and the hydraulic line of the second hydraulic line (97) are merged; And a control unit that is provided in first and second control valves (130, 140) for controlling the operating oil supplied to the actuator, and supplies a part of the operating oil to the actuator by using the position energy or inertia energy generated by the driving of the actuator Circuitry; An actuator use flow rate calculation unit 1110 for calculating a regeneration flow rate Qregen supplied from the regeneration circuit unit to the actuator; The regeneration flow rate Qregen is subtracted from the required flow rate Qset inputted by the operation of the driver's joystick to determine the flow rate Qscyl currently being used and the flow rate to be discharged from the first pump 70a or the second pump 70b (Qpump), the flow rate of which is merged when the first hydraulic line (91) and the second hydraulic line (97) are merged is added to or subtracted from the flow rate (Qpump) to be discharged, A swash plate control part (1220) for calculating the swash plate angle of the pump so as to discharge the working oil; And an electronic proportional pressure reducing valve driver 230 for controlling swash angles of the first and second pumps 70a and 70b based on the result determined by the swash plate controller 1220. [

The details of other embodiments are included in the detailed description and drawings.

The electromagnetic hydraulic system of the construction equipment according to an embodiment of the present invention as described above can sense the operation state of each actuator and can control the flow direction control valve by the electronic calculation processing of the sensed signal, So that the safe operation of the construction equipment can be guaranteed.

Further, the electromagnetic hydraulic system of the construction equipment according to the embodiment of the present invention can more precisely predict and control the flow rate, so that the operation time of the engine and the pump can be reduced to the optimum state, and the controllability of the flow rate and the hydraulic pressure can be improved And improve fuel economy.

BRIEF DESCRIPTION OF THE DRAWINGS The advantages and features of the present invention, and how to accomplish them, will become apparent by reference to the embodiments described in detail below with reference to the accompanying drawings.

Like reference numerals refer to like elements throughout the specification.

Hereinafter, an electromagnetic hydraulic system of a construction equipment according to an embodiment of the present invention will be described with reference to FIGS. 1 to 4. FIG.

Fig. 4 is a view showing a hydraulic circuit for explaining an electrohydraulic system of a construction equipment according to an embodiment of the present invention, Fig. 5 is a view showing an example of a hydraulic circuit of Fig. 4 Fig.

As shown in Figs. 1 and 4, the construction equipment includes an upper body turning on the upper side of the lower body, a boom disposed forwardly and upwardly and downwardly angularly rotatably on the upper body, And a bucket which is disposed so as to be angularly rotatable up and down on the outside of the arm.

In addition, the above-mentioned boom and each of the actuators 40, 50, 60 for driving the arm or bucket are disposed, and the above-mentioned upper body is provided with a first pump 70a for supplying the working oil to the above- Or the second pump 70b and the engine are arranged.

Further, a first traveling motor 10 and a second traveling motor 20, which are responsible for running the construction equipment, are further disposed, and a first actuator 30 for swiveling the above-mentioned upper body is disposed.

The first pump 70a or the second pump 70b varies the flow rate and pressure of the hydraulic oil by the angle control of the swash plate, and the discharged hydraulic oil is supplied to each of the above-described working actuators.

Each of the above-mentioned working actuators includes a first actuator 30 for turning the upper body, a second actuator 40 for raising and lowering the boom, a third actuator 50 for swinging and unlocking the arm, and a fourth actuator 60).

A directional control valve 80 may be disposed between the first pump 70a or the second pump 70b and each of the above-described working actuators. The directional control valve 80 may be a 2- In the first position, the input port and the output port are directly connected. In the second position, the input port and the output port are staggered.

The first pump 70a or the second pump 70b recovers the operating oil by using the energy of position of the boom, the arm, and the bucket and the inertia energy of the upper body, 70a or the second pump 70b and can control the first and second pumps 70a, 70b by using the above-described potential energy and inertial energy, Will be described with reference to FIG.

FIG. 2 is a diagram illustrating a hydraulic circuit for explaining an electrohydraulic system of a construction equipment according to an embodiment of the present invention, and FIG. 3 is a diagram illustrating a control unit in the electrohydraulic system of a construction equipment according to an embodiment of the present invention. Fig.

In the construction equipment, each work actuator for driving the boom and the above-mentioned arm or bucket is disposed. On the above-mentioned upper body, the pump 110 and the engine 120 for supplying the working oil to the above-mentioned working actuator are arranged.

The above-mentioned pump 110 varies the flow rate and pressure of the operating oil by the angle control of the swash plate, and the discharged operating fluid is supplied to each of the above-mentioned actuators.

The swash plate angle detecting portion 111 is disposed on one side of the pump 110 to detect the angle of the swash plate and a discharge hydraulic pressure detecting portion 112 is disposed on the side where the hydraulic fluid is discharged from the pump 110 Thereby detecting the operating oil discharge pressure.

The engine 120 detects the speed of the engine 120 and the power output from the engine 120 is transmitted to the pump 110 through the above- .

An actuator pressure detecting unit connected to the working actuator so as to be able to be driven by the above-described pump 110 so as to be able to transmit the working oil and detecting the hydraulic pressure at the head side and the rod side of the above-mentioned working actuator is disposed.

The above-described working actuator may include, for example, a first actuator 150 for driving the arm and a second actuator 160 for driving the boom, and an actuator pressure detecting unit may be disposed in each of the working actuators.

For example, the first head side pressure detection portion 151 is disposed on the head side and the first load side pressure detection portion 152 is disposed on the rod side by detecting the hydraulic pressure applied to the first actuator 150.

The second head side pressure detecting portion 161 is disposed on the head side and the second rod side pressure detection detecting portion 162 is disposed on the rod side by detecting the hydraulic pressure acting on the second actuator 160 described above.

In addition, a control valve for controlling the above-described working actuator is disposed, for example, a first control valve 130 is disposed in the first actuator 150, a second control valve 140 is disposed in the second actuator 160 .

The first and second control valves 130 and 140 may be provided with a plurality of spools and a flow path orifice for switching the flow path connected to the head side and the rod side of each of the actuators 150 and 160 The known technologies such as the spool and the flow path (orifice) are applied, and a detailed description thereof will be omitted.

The first control valve 130 is provided with a first spool position detection section 131, and the second control section 130 is provided with a second spool position detection section 131. The first spool position detection section 131 detects the position of the spool, The valve 140 is provided with a second spool position detecting portion 141.

The first and second control valves 130 and 140 can change the traveling direction of the hydraulic oil according to the degree of movement of the spool, and the spool is moved according to the applied electric control signal.

That is, the spool position of the control valve described above can be calculated by the resultant value measured by the first spool position detecting section 131 or the second spool position detecting section 141, As the basic data for calculating the opening amount of the gas.

Further, when the working device connected to the actuator described above is driven by either one of the self-weight or inertia, the actuator is connected to the head side and the rod-side hydraulic line of the actuator and is discharged from either the head side or the rod side of the actuator And a regeneration circuit portion for supplying a part of the operating fluid to the other of the head side and the rod side of the actuator.

The detection result values of the swash plate angle detection unit 111, the discharge hydraulic pressure detection unit 112, the engine speed detection unit 121, the actuator pressure detection unit, and the spool position detection unit are inputted and calculated, And a control unit (C) for controlling the pump (110) and the control valve.

An electronic joystick 1300 may be disposed in the control unit C and an electronic joystick 1300 may be operated by a driver of the construction equipment. When the electronic joystick 1300 is operated, And the control signal is applied to the control unit C described above.

The above-described control unit C will be described in more detail with reference to Fig.

The control unit C includes a valve control unit 1100 and a pump control unit 1200.

The valve control unit 1100 described above includes the actuator use flow rate calculation unit 110 for calculating the flow rate value Qscyl used in the above-described working actuator and the required flow rate value A spool controller 120 for calculating a spool control result value by calculating a flow rate value between a result of the actuator use flow rate calculator 110 and a result value of the actuator usage flow rate calculator 110 and a result value calculated by the spool controller 120, And an electronic proportional pressure reducing valve drive 130 for driving the spool of the valve.

The actuator use flow rate calculation unit 110 receives the result of detecting the position of the spool in the control valve, receives the result of the detection by the actuator pressure detection unit, And the resultant value is received.

The pump control unit 1200 includes a discharge flow rate calculation unit 210 for calculating a flow rate discharged from the pump 110, a flow rate detection unit 210 for detecting the flow rate Qset required by the control of the electronic joystick, A swash plate control unit 220 for calculating a slope angle of the swash plate by calculating a flow rate Qpump obtained by subtracting a flow rate of the regeneration flow rate calculated by calculating a value of the regeneration flow rate and a flow rate discharged from the pump 110, And an electronic proportional pressure reducing valve driver 230 for controlling the pump 110 based on a result determined by the proportional pressure reducing valve 220.

The swash plate control unit 220 receives the detection value of the swash plate angle detection unit 111 and the detection value of the engine speed detection unit 121 described above, (111).

Referring to FIG. 3, a regeneration flow rate in an electrohydraulic system of a construction equipment according to an embodiment of the present invention will be described.

First, a command signal generated from the electronic joystick 1300 is received by the control unit C. [

The above-mentioned command signal may be a signal corresponding to the required flow rate Qset corresponding to the speed of the actuator.

The actuator usage flow rate calculation unit 110 may be configured to calculate the detected value of the spool displacement from the first or second spool position detection unit 131 or 141 disposed in the first control valve 130 or the second control valve 140 And receives detection values from the first or second head side pressure detection portions 151 and 161 and the first or second rod side pressure detection detection portions 152 and 162 and detects the detection of the discharge hydraulic pressure detection portion 112 Value.

At this time, the actuator use flow rate calculation unit 110 predicts the flow rate currently used by the actuator through the orifice equation of the following equation (1).

Here, Qscyl is the flow rate of the actuator,

Ppump: Pump discharge pressure,

Pcyl: Actuator load pressure,

A (x): the opening area of the valve defined by the spool position x,

Cq: Flow coefficient,

ρ is the fluid density.

The spool controller 120 receives the error value between the actuator flow rate Qset requesting operation of the electronic joystick 1300 and the current actuator use flow rate Qscyl and outputs the error value to the first or second control valve 130, 140 of the spool.

The spool position command (Xspool) determined from the spool controller is converted into an electric signal (supply current) through the electron proportional pressure reducing valve driving part 130, and the electric signal The spool positions of the first or second control valve 130, 140 described above are changed.

The pump control unit 1200 controls the swash plate angle of the pump 110 so that the working actuator can discharge only the flow amount required by the working actuator.

The pump control unit 1200 includes a discharge flow rate calculation unit 210 for predicting a current discharge flow rate, a swash plate angle control unit 220 for calculating a swash plate angle control command by comparing the pump flow rate and the current discharge flow rate, And an electronic proportional pressure reducing valve driver 230 for driving an electronic proportional pressure reducing valve that generates a pressure to be adjusted.

The above-described pump required flow rate (Qpump) can be expressed by the following equation.

Qpump = Qset - Qregen

Where Qpump is the pump demand flow rate,

Qset: required flow value generated by control of electronic joystick,

Qregen: Flow rate regenerated.

The discharge flow rate calculation unit 210 calculates the current pump discharge flow rate based on the following equation (3) by receiving the detection value of the swash plate angle detection unit 111 and the detection value of the engine speed detection unit 121.

Here, Qspump: current discharge flow rate,

ω: engine speed,

DELTA V is the displacement of the pump.

The swash plate control unit 220 receives the error value between the pump required flow rate Qpump and the current discharge flow rate Qspump and receives the detection value of the discharge hydraulic pressure detection unit 112 of the pump 110 to calculate the swash plate angle .

Various control algorithms can be implemented so that the error value can be quickly eliminated. As an example, the swash angle control algorithm may be a flow control and a horsepower control algorithm.

The swash angle command Xangle determined from the swash plate control unit 220 may be switched to a control signal (supply current) through the electron proportional pressure reducing valve drive unit 230 to change the angle of the swash plate.

Generally, the difference between the required flow rate (Qpump) required by the pump and the required flow rate (Qset) required by the control of the electronic joystick varies due to the regeneration effect of the valve, and the flow rate required for the regeneration (Qpump) should be calculated.

The above-mentioned flow regeneration is a function implemented in a control valve. It is a function of the position energy when the arm is crowded and the boom is down, or the inertia energy when the upper body is turned. Means that the required flow rate is reduced by re-supplying the operating fluid discharged from one side of the cylinder (or motor) to the other side of the cylinder (or motor) again.

That is, when the arm is slammed or the boom is lowered, the flow rate discharged from the actuator by its own weight is used as a part of the flow rate flowing into the actuator without flowing into the tank, thereby saving energy and increasing the speed.

Therefore, the pump required flow rate (Qpump) to be actually discharged from the pump corresponds to the required flow rate (Qset) required by control of the electronic joystick minus the flow rate (Qregen) regenerated.

The working actuator of the embodiment of the present invention may correspond to the first actuator 150 that drives the arm and may correspond to the second actuator 160 that drives the boom.

The first actuator 150 described above drives the arm to use the regeneration flow rate when the first actuator 150 is driven to extend.

The flow amount of the rod side of the first actuator 150 is discharged by its own weight when the arm is retracted.

This flow rate passes through the main spool Aout of the first control valve 130 and flows to the tank through the flow path 35 of the regeneration releasing circuit.

On the other hand, the pressure p * after passing through the main spool is generally higher than the cylinder head pressure of the first actuator 150 because the speed is controlled through the meter-out control.

Therefore, a part of the flow rate on the rod side is joined to the pump flow rate through the first internal flow path 132 and supplied to the cylinder head of the first actuator 150.

The regeneration flow rate Qregen used in the first actuator 150 can be calculated by the following equations (4) and (5).

Here, Qregen: regeneration flow rate,

Aregen: Regeneration valve (check valve) Euro area,

P *: pressure between spool and regeneration circuit,

Ppump: Pump discharge pressure,

Cq: Flow coefficient,

ρ: fluid density,

α = Arod / Ahead: arm cylinder load area to head area ratio,

Qscyl: Actuator flow rate,

Aout: Spool opening area connected from the actuator to the tank,

Prod: Load pressure on arm load side.

Further, a regeneration flow rate is generated when the boom is disrupted.

When the boom descends, part of the head side flow rate of the second actuator 160 is regenerated to the boom rod side through the second internal flow path 142 due to its own weight, and at this time, the regeneration flow rate Qregen of the second actuator 160 is Can be calculated by the following equation (6).

Here, Qregen: regeneration flow rate,

Aregen: Regeneration valve (check valve) Euro area,

Ppump: Pump discharge pressure,

Cq: Flow coefficient,

ρ: fluid density,

Phead: Load pressure on the boom head.

Therefore, the required flow rate for discharging the hydraulic fluid by substantially driving the pump can be calculated by the following equation (7).

Here, Qpump is the flow rate to be discharged by the pump,

Qset: Required flow rate by control of electronic joystick,

Qregen: Regeneration flow rate generated in the first or second actuator 150, 160.

On the other hand, as shown in Fig. 5, the first pump 70a takes charge of the first actuator group composed of the first traveling motor 10, the second actuator 40 and the fourth actuator 60 And the second pump 70b can supply the hydraulic oil with the second actuator group 20 constituted by the second actuator group constituted by the third actuator 50 and the first actuator 30 as the main charge have.

The hydraulic fluid discharged from the first pump 70a is transferred to the first hydraulic group 91 and supplied to the first actuator group described above and the hydraulic fluid discharged from the second pump 70b is supplied to the second hydraulic line 97 To be supplied to the above-described second actuator group.

The first hydraulic line 91 and the second hydraulic line 97 described above may be further provided with a direction switching valve 80 capable of switching or joining the flow of hydraulic oil.

The actuators of the first pump 70a and the second pump 70b described above can be expressed by the following equations (8) and (9).

here,

Qpump1: The flow rate to be discharged from the first pump (70a)

Qpump2: Flow rate to be discharged from the first pump (70a)

Qtravel_L: Flow rate required by the first traveling motor (10)

Qtravel_R: Flow rate required by the second traveling motor (20)

Qswing: The flow rate required by the first actuator 30, which is the swing motor,

Qboom2, Qboom1: the flow rate required by the second actuator 40 for driving the boom

Qarm1, Qarm2: the flow rate required by the second actuator 50 for driving the arm

Qbucket: The flow rate required by the fourth actuator 60 for driving the bucket

Therefore, each of the above-described working actuators can be driven in a state in which the construction equipment stops without running, i.e., the first and second traveling motors 10 and 20 are not driven, and this state is a universal state.

When the construction equipment is then driven, the first and second traveling motors 10 and 20 are driven and the actuator can be driven while the construction equipment is running. For example, as shown in FIG. 6, When the actuator 60 is driven, the directional control valve 80 described above is operated to change the hydraulic circuit.

At this time, the actuators of the first pump 70a and the second pump 70b can be expressed by the following equations (10) and (11).

The flow rate to be supplemented in the above equation (10) can be calculated by the following equation (12) without installing a separate sensor.

Here Qrest: the flow rate supplemented by boom, arm, bucket, swing motion in pump 1,

     Apt_travel_L: Open area of the center bypass channel in the right-hand spool,

     P1: pressure of the first pump 1,

     P2: pressure of the second pump 2,

     Cq: Flow coefficient,

     ρ is the fluid density.

In addition, the flow rate to be supplemented in the above Equation (11) can be calculated by the following Equation (13) without installing a separate sensor.

Where Qtravel_2 is the flow rate supplemented by the travel operation in the second pump,

       Adrive: orifice area,

       P1: pressure of the first pump,

       P2: pressure of the second pump,

       Cq: Flow coefficient,

      ρ is the fluid density.

On the other hand, as described above, the change in the hydraulic circuit configuration can be recognized from the spool displacement from the displacement sensor e in the actuator use flow rate calculation section.

Hereinafter, a modification of the hydraulic circuit configuration will be described in more detail.

If the directional control valve 80 is not operated and hydraulic pressure is supplied to the working actuator of the first and second pumps 70a and 70b in the reference configuration, any one of the first and second pumps 70a and 70b Since the first and second traveling motors 10 and 20 are in operation, hydraulic oil must be supplied to the other working actuators, which may result in a lack of hydraulic pressure. Even if the first pump 70a and the second pump 70b are the same It can not be guaranteed to rotate by the number of revolutions so that the straightness of the construction equipment can not be guaranteed.

However, in the electrohydraulic system of the construction equipment according to the embodiment of the present invention, when the driving signal of the above-described working actuator is applied, the directional control valve 80 is switched from the first position to the second position, 70b are connected to the first traveling motor 10 and the first pump 70a is connected to the above-described working actuator.

Accordingly, the second pump 70b takes charge of the first traveling motor 10 and the second traveling motor 20, so that the progress of the construction equipment can be assured and the operation liquid heater can be driven even during traveling of the construction equipment .

In addition, a plurality of control valves for controlling the above-described working actuator and the above-described first and second traveling motors 10 and 20 are disposed, and in particular, a plurality of control valves for controlling the spool positions of the respective control valves A detection unit can be disposed.

The control unit C may be arranged to receive and receive the detection values of the plurality of detection units and to send a command signal to the directional control valve 80 based on the calculated result values, And is associated with an electronic joystick 1300 disposed in the cab of the equipment.

On the other hand, a first check valve 81 for supplying the hydraulic oil discharged from the first pump 70a to the first traveling motor 10 and preventing the reverse flow of the hydraulic oil may be further disposed.

When the directional control valve 80 is switched to the second position and the second pump 70b takes charge of the first and second traveling motors 10 and 20, So that part of the operating oil discharged from the first traveling motor 10 can be supplied to the first traveling motor 10.

On the other hand, the second check valve 82 for supplying the working oil discharged from the second pump 70b to the above-mentioned working actuator and preventing the back flow of the operating oil may be further arranged, A second control valve 200 for controlling the driving of the motor 20 may be further disposed.

Particularly, when the second control valve 200 is stopped, the hydraulic oil discharged from the second pump 70b is supplied to the second check valve (not shown) via the center bypass port of the second control valve 200 82 and the hydraulic oil passed through the second check valve 82 can be supplied to the actuators of some of the working actuators and more specifically to the first and third actuators 30,

Hereinafter, an operation example of an electrohydraulic system of a construction equipment according to an embodiment of the present invention will be described with reference to FIGS. 5 and 6.

FIG. 5 clearly shows that the actuators of the first pump 70a and the second pump 70b are clearly distinguished.

That is, the first pump 70a serves as the first actuator 10 for driving the boom, the second actuator 40 for driving the boom, and the fourth actuator 60 for driving the bucket, and the second pump 70b A third actuator 50 for driving the two-travel motor 20 and the arm, and a first actuator 30 for swinging the upper body.

In particular, when the construction equipment is not traveling, that is, when the first and second traveling motors 10 and 20 are not driven, the respective working actuators are driven.

Then, when the construction equipment is driven, the first and second traveling motors 10 and 20 are driven.

As described above, the driving of the working actuator when driving the working actuator when the construction equipment is running is detected by the spool position detecting unit disposed at each control valve, and the signal is transmitted to the control unit (C).

The control unit C determines whether the working actuator is driven when the first and second traveling motors 10 and 20 are being driven and if the first and second traveling motors 10 and 20 are operating, The directional control valve 80 is switched to the second position.

That is, when the direction control valve 80 is operated as shown in Fig. 6, the hydraulic circuit is changed, and the hydraulic circuit of Fig. 6 can be represented schematically in Fig. 7 as a conceptual diagram.

The first pump 70a supplies the working oil to the working actuator and the second pump 70b takes charge of the first and second traveling motors 10 and 20 as shown in Fig. 6 or Fig.

At this time, a part of the hydraulic fluid discharged from the first pump 70a may be joined to the hydraulic line supplied from the first pump 70b through the first check valve 81. [

Accordingly, the second pump 70b can uniformly supply the predetermined amount of the working oil to the first traveling motor 10 and the second traveling motor 20, thereby enabling more precise traveling in the movement of the construction equipment, .

Particularly, the required flow rate Qset is calculated on the basis of the signal output from the electronic control unit, and the flow rate Qcyl currently in use and the discharge flow rate discharged from the present pump are subtracted based on the sensors provided on the control valve and the hydraulic line , The flow rate Qpump to be further discharged from the pump is calculated and the discharge flow rate Qpump is corrected in consideration of the combined flow amount when the hydraulic fluid discharged from the first pump 70a and the hydraulic fluid discharged from the second pump 70b are merged The swash plate angle of the first pump 70a or the second pump 70b can be controlled.

In addition, it is possible to drive the working actuator during the traveling of the construction equipment, thereby enabling a complex operation.

Also, in an embodiment of the present invention, as in the prior art according to the electro-hydraulic system of the construction equipment, in order to compensate for the hydraulic pressure shortage caused by driving the working actuator during driving of the first pump 70a or the second pump 70b, The optimum flow rate necessary for driving the first and second traveling motors 10 and 20 and the working actuator can be discharged and the fuel consumption can be improved.

As described above, the control unit C calculates the detection values obtained from the respective detection units to control the first or second control valves 130 and 140 and the pump 110 to determine the optimum flow rate corresponding to the required flow rate as So that it can be discharged.

In other words, as described above, according to the electromagnetic hydraulic system according to the embodiment of the present invention, the function of the flow regeneration of the conventional open center flow control hydraulic system, the function of operating the two pumps, and the reliability of the already- Thereby enabling precise flow rate distribution and flow rate distribution.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art. will be.

It is therefore to be understood that the embodiments described above are to be considered in all respects only as illustrative and not restrictive, the scope of the invention being indicated by the appended claims, It is intended that all changes and modifications derived from the equivalent concept be included within the scope of the present invention.

The electromagnetic hydraulic system of the construction equipment according to the embodiment of the present invention can be used in construction equipment, and in particular, even if a plurality of pumps are provided and each pump takes charge of a specific actuator, It is possible to ensure safe operation of construction equipment.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an explanatory diagram for illustrating a construction equipment. FIG.

4 is a diagram illustrating a hydraulic circuit for explaining an electrohydraulic system of a construction equipment according to an embodiment of the present invention.

Fig. 5 is a simplified diagram of an example hydraulic circuit of Fig. 4;

6 is a diagram illustrating a hydraulic circuit for explaining a case where a specific actuator is driven during traveling in an electromagnetic hydraulic system of a construction equipment according to an embodiment of the present invention.

FIG. 7 is a simplified view of the oil circuit example of FIG. 6; FIG.

DESCRIPTION OF THE REFERENCE NUMERALS (S)

10, 20: first and second traveling motors

30, 40, 50, 60: first, second, third and fourth actuators

70a, 70b: first and second pumps

80: Direction control valves 81, 82: First and second check valves

91: first hydraulic lines 92a and 92b: second and third hydraulic lines

93: fourth hydraulic line 94: fifth hydraulic line

95: sixth hydraulic line 96: seventh hydraulic line

97: eighth hydraulic line 98: ninth hydraulic line

99: No. 10 hydraulic line

100, 200, 300, 400, 500, 600: first, second, third, fourth, fifth, sixth control valves

C:

Claims (5)

First and second pumps (70a, 70b) capable of varying the discharge flow rate of the working oil and supplying working fluid to the first and second actuator groups connected to the working device, respectively; A first hydraulic line 91 in which the hydraulic fluid discharged from the first pump 70a is transferred to the first actuator group; A second hydraulic line (97) through which the hydraulic fluid discharged from the second pump (70b) is transferred to the second actuator group; A direction switching valve (80) for switching the direction in which the working fluid of the first hydraulic line (91) and the hydraulic line of the second hydraulic line (97) are merged; A first control valve (130) for controlling hydraulic fluid supplied to the first actuator group; A second control valve (140) for controlling hydraulic fluid supplied to the second actuator group; A regeneration circuit unit which is provided in each of the first and second control valves 130 and 140 and supplies a part of the operating fluid to the actuator using regenerative energy or inertial energy generated by the actuator; First and second spool position detectors (131, 141) for detecting respective spool positions of the first and second control valves (130, 140); The opening amounts of the first and second control valves (130, 140) are calculated by the positions of the spools detected by the first and second spool position detecting portions (131, 141) An actuator use flow rate calculation unit 1110 that calculates a flow rate to be used in each of the first and second actuator groups by calculating a regeneration flow rate Qregen supplied to each of the actuator groups; A detection value obtained by detecting the swash plate angle of the first and second pumps 70a and 70b in operation and a detection value obtained by detecting the rotational speeds of the first and second pumps 70a and 70b, A discharge flow rate calculator 1210 that calculates a detection value that detects the discharge pressure of the operating oil discharged by the first and second pumps 70a and 70b and calculates a discharge flow rate Qspump discharged by the first and second pumps 70a and 70b, ); The flow rate Qscyl currently used is subtracted from the regeneration flow rate Qregen and the discharge flow rate Qspump at the required flow rate Qset input by the operation of the joystick of the driver and the current flow rate Qscyl is subtracted from the present first and second pumps 70a and 70b The flow rate Qpump to be discharged is calculated and the flow rate of the combined flow when the first hydraulic line 91 and the second hydraulic line 97 are merged is added to or subtracted from the flow rate Qpump to be discharged, A swash plate control part (1220) for calculating a swash plate angle of the first and second pumps (70a, 70b) so that the hydraulic oil is discharged by a resultant value; And An electron proportional pressure reducing valve driver 1230 for controlling swash angles of the first and second pumps 70a and 70b according to a result determined by the swash plate controller 1220; And an electromagnetic hydraulic system of the construction equipment. The method according to claim 1, The rotational speeds of the first and second pumps 70a and 70b are calculated by calculating the rotational speed of the engine detected by the engine speed detecting unit 121; The electronic hydraulic system of construction equipment is characterized by. The method according to claim 1, The first pump 70a supplies the working oil to the first actuator group including the space row motor in the steady state and the second pump 70b supplies the working oil to the second actuator group including the left traveling motor in the steady state. , ≪ / RTI & The first pump 70a supplies the operating fluid to the second actuator group except for the first actuator group and the left traveling motor by switching the direction switching valve, The second pump 70b supplies operating fluid only to the space row motor and the left traveling motor, The swash plate control part 1220 controls the swash plate angles of the first and second pumps 70a and 70b in accordance with the change of the actuators of the first pump 70a and the second pump 70b. The electronic hydraulic system of construction equipment is characterized by. The method according to claim 1, Wherein the flow rate (Qrest) to be replenished by the first pump (70a) is obtained by the following equation.

Here Qrest: the flow rate supplemented by boom, arm, bucket, swing motion in pump 1,      Apt_travel_L: Open area of the center bypass channel in the right-hand spool,      P1: pressure of the first pump 1,      P2: pressure of the second pump 2,      Cq: Flow coefficient,      ρ is the fluid density. The method according to claim 1, And the flow rate (Qtravel_2) to be supplemented by the second pump (70b) is obtained by the following equation.

Where Qtravel_2 is the flow rate supplemented by the travel operation in the second pump,        Adrive: orifice area,        P1: pressure of the first pump,        P2: pressure of the second pump,        Cq: Flow coefficient,       ρ is the fluid density.

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