KR101449007B1 - Electric oil pressure system of construction equipment - Google Patents

Abstract

The present invention relates to an electromagnetic hydraulic system of a construction equipment, and more particularly, to a hydraulic system for a construction equipment, which comprises a pump (10) capable of varying the discharge flow rate of hydraulic fluid, a pump (10) for supplying hydraulic fluid to an actuator When the working device provided to the control valves 30 and 40 and driven by the actuators is driven by either self weight or inertia, the head side and the rod side hydraulic line of the actuator are connected to each other on the head side and the rod side of the actuator A regenerative circuit portion for supplying a part of the hydraulic oil discharged from one of the hydraulic pumps to the other of the head side and the rod side of the actuator, the head side hydraulic pressure measurement value of the actuator and the rod hydraulic pressure measurement value, And calculates a regeneration flow rate Qregen supplied to the actuator by the regeneration circuit unit A swash plate control part 220 and a swash plate control part 220 for calculating the swash plate angle of the pump so as to discharge the hydraulic oil by the difference of the regeneration flow rate Qregen at the required flow rate Qset inputted by the operation of the joystick of the driver, And an electron proportional pressure reducing valve driver 230 for controlling the swash plate angle of the pump 10 based on the determined result value.

Construction machinery, construction equipment, hydraulic circuit, hydraulic system, hydraulic oil, regeneration, electronic control

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 hydraulic pump that generates hydraulic pressure by using the power of the engine and the engine, a control unit that controls the hydraulic pressure generated by the hydraulic 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 in accordance with the control of the flow rate and the hydraulic pressure, and for example, the actuator performs specific work while operating a boom, an arm, a bucket, At this time, the flow rate and the hydraulic pressure applied to the respective actuators should be controlled.

An open center type flow control system and a load sensing hydraulic system are known as technologies for controlling hydraulic pressure and flow rate.

The open center type flow control system of the above-mentioned electronically controls a negative flow rate control method in which the pressure generated in the upstream side of the orifice by the flow rate to the tank through the center by-pass acts on the flow rate control part to control the swash plate angle of the pump , And a positive flow rate control method in which the pilot pressure of the joystick is selected and acts on the flow rate control part to control the swash plate angle of the pump. In the above two control methods, And is branched to the path path and the actuator path.

On the other hand, it is known that the above-mentioned load-sensing hydraulic system of the above-described type is capable of distributing the flow rate independent of the actuator load through a pressure compensator without generating an excessive flow rate.

However, the above-described load sensing hydraulic system fails to utilize the position energy that naturally acts on the rod of the actuator and thus can not efficiently use the energy.

In addition, since the conventional technique for controlling the hydraulic pressure and the flow rate as described above is performed by a mechanical type, it is difficult to control precisely and there is a problem that the pump and the engine must be always operated excessively in response to the operation of the actuator. .

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a method and apparatus for regenerating oil pressure and flow rate by using position energy acting on an actuator, thereby improving energy utilization efficiency, And it is an object of the present invention to provide an electrohydraulic system of a construction equipment capable of operating in an optimal state to improve fuel economy.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are not intended to limit the invention to the precise forms disclosed. Other objects, which will be apparent to those skilled in the art, It will be possible.

According to an aspect of the present invention, there is provided an electromagnetic hydraulic system for a construction equipment, including: a pump capable of varying a discharge flow rate of hydraulic fluid; a pump for supplying hydraulic fluid to an actuator connected to a work device; Wherein the actuator is provided with a control valve that controls the flow path of the hydraulic fluid supplied to the actuator, and when the working device connected to the actuator is driven by one of the self-weight or inertia, A regeneration circuit for connecting some of the hydraulic fluid discharged from one of the head side and the rod side of the actuator to the other of the head side and the rod side of the actuator; Calculating a discharge oil pressure measurement value of the pump and an opening amount measurement value of the control valve, and calculating a regeneration flow rate (Qregen) supplied to the actuator by the regeneration circuit unit An actuator use flow rate calculator; A swash plate control unit for calculating a swash plate angle of the pump so that the hydraulic oil is discharged by a difference of the regeneration flow rate Qregen from a required flow rate Qset input by a joystick operation of the driver; And an electronic proportional pressure reducing valve driving unit for controlling the swash plate angle of the pump based on the resultant value determined by the swash plate control unit.

Further, it is also possible to calculate a detection value that detects a swash plate angle of the pump being driven, a detection value that detects the rotation number of the pump, and a detection value that detects a discharge pressure of the hydraulic oil discharged by the pump, Wherein the swash plate control part calculates a flow rate of the remaining flow excluding the regeneration flow rate (Qregen) and the discharge flow rate (Qspump) from the required flow rate (Qset) And calculating the swash plate angle of the pump which can be further discharged from the pump.

Further, the opening amount of the control valve is calculated by calculating the spool position of the control valve measured by the first and second spool position detecting portions, and the rotational speed of the pump is calculated by the rotational speed of the engine detected by the engine speed detecting portion And may be calculated by calculating the speed.

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

The electro-hydraulic system of the construction equipment according to the present invention as described above can utilize the potential energy acting on each actuator, and in particular, regenerates part of the hydraulic pressure and flow rate generated when the actuator is lowered by its own weight It can be used.

Further, the electromagnetic hydraulic system of the construction equipment according to the embodiment of the present invention can more precisely control the flow rate, thereby reducing the operation time of the engine and the hydraulic pump to the optimal state, improving the controllability of the flow rate and the hydraulic pressure Fuel efficiency can be improved.

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 3. FIG.

FIG. 2 is a view illustrating an example of a hydraulic circuit for explaining an electrohydraulic system of a construction equipment according to an embodiment of the present invention. FIG. 3 is a schematic view of an embodiment of the present invention. 1 is an exemplary view for explaining a control unit in an electrohydraulic system of a construction equipment according to an example.

As shown in Fig. 1, the construction equipment includes a boom that is vertically rotatable in an up-and-down direction on an upper body and an upper body that are pivoted on the upper side of the lower body, And a bucket which is disposed so as to be rotatable in an up-and-down direction at an outer side of the arm.

Each of the actuators for driving the boom and the above-described arm or bucket is disposed. On the upper body, the pump 10 and the engine 20 for supplying the working oil to the above-described working actuator are disposed.

On the other hand, a driving motor for driving the upper body to rotate and a left traveling motor and a right traveling motor for driving the construction equipment may be further disposed.

The above-described pump 10 varies the flow rate and pressure of the operating oil by the angle control of the swash plate, and the discharged working oil is supplied to each of the above-mentioned actuators.

The swash plate angle detecting portion 11 is disposed on one side of the pump 10 to detect the angle of the swash plate and the discharge hydraulic pressure detecting portion 12 is disposed on the side where the hydraulic fluid is discharged from the pump 10 Thereby detecting the operating oil discharge pressure.

The engine 20 is provided with an engine speed detecting portion 21 on one side thereof so that the engine speed detecting portion 21 detects the speed of the engine 20 and the power output from the engine 20 is transmitted to 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 10 so as to be able to transmit the working oil and for detecting the hydraulic pressure at the head side and the rod side of the above-mentioned working actuator.

The above-described working actuator may include, for example, a first actuator 50 for driving the arm and a second actuator 60 for driving the boom, and an actuator pressure detecting portion may be disposed in each of the working actuators.

For example, the first head side pressure detection portion 51 is disposed on the head side and the first load side pressure detection portion 52 is disposed on the rod side by detecting the hydraulic pressure acting on the first actuator 50 described above.

The second head side pressure detection portion 61 is disposed on the head side and the second rod side pressure detection portion 62 is disposed on the rod side by detecting the hydraulic pressure acting on the second actuator 60 described above.

A control valve for controlling the above-described working actuator is disposed, for example, a first control valve 30 is disposed in the first actuator 50 and a second control valve 40 is disposed in the second actuator 60 .

The first and second control valves 30 and 40 are provided for substantially switching the control valves 30 and 40 to switch the flow path connected to the head side and the rod side of each of the actuators 50 and 60 A plurality of spools and a flow path (orifice), and the like. The technology of the spool and the flow path (orifice) and the like is applied to a known technique, and the first and second control valves The spool, the flow path (orifice), and the like are simply shown so that only the regeneration circuit is symbolically exposed for the sake of understanding.

The first control valve 30 is provided with a first spool position detection section 31, and the second control valve 30 is provided with a second spool position detection section 31. The first control valve 30 is provided with a spool position detection section for detecting the spool position. The valve 40 is provided with a second spool position detecting portion 41.

The first and second control valves 30 and 40 can change the traveling direction of the hydraulic fluid 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 above-described control valve can be calculated by the resultant value measured by the above-described first spool position detecting portion 31 or second spool position detecting portion 41, 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 regeneration circuit portion may be a first internal flow path 32 and a check valve 33 as shown in detail in Fig. 4 and may include a second internal flow path 42 and a check valve 33, (43), and the operation of the regeneration circuit will be described later.

The detection result values of the swash plate angle detecting section 11, the discharge hydraulic pressure detecting section 12, the engine speed detecting section 21, the actuator pressure detecting section, and the spool position detecting section are inputted and calculated, And a controller (C) for controlling the pump (10) and the control valve according to the value of the control signal.

An electronic joystick 300 may be disposed in the control unit C and the electronic joystick 300 may be operated by a driver of the construction equipment. When the electronic joystick 300 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 the valve control unit 100 and the pump control unit 200.

The valve control unit 100 includes the actuator use flow rate calculation unit 110 for calculating the flow rate value Qscyl used in the above-described work 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 usage flow rate calculator 110 and a result value of the actuator usage flow rate calculator 110, 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 detection of the position of the spool in the control valve and receives the result of the detection by the actuator pressure detection unit. And the resultant value is received.

The pump control unit 200 described above includes a discharge flow rate calculation unit 210 for calculating a flow rate discharged from the pump 10, an actuator pressure detection unit 210 for detecting a 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 a regeneration flow rate calculated by calculating a detected value and a flow rate discharged from the pump 10, And an electronic proportional pressure reducing valve driver 230 for controlling the pump 10 according to a result determined by the controller 220.

The swash plate control unit 220 receives the detection value of the swash plate angle detection unit 11 and the detection value of the engine speed detection unit 21 described above, (11).

The operation of the electrohydraulic system of the construction equipment according to an embodiment of the present invention will be described with reference to FIGS. 3 to 5.

First, a command signal generated from the electronic joystick 300 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 use flow rate calculation unit 110 calculates the detected value of the spool displacement from the first or second spool position detection unit 31 or 41 disposed in the first control valve 30 or the second control valve 40 And receives a detection value from the first or second head side pressure detecting section 51 or 61 and the first or second load side pressure detecting detecting section 52 or 62. When the discharge hydraulic pressure detecting section 12 ) Is received.

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).

Where Qscyl is the actuator use flow rate, Ppump is the pump discharge pressure, Pcyl is the actuator load pressure, A (x) is the opening area of the valve defined by the spool position x, Cq is the flow coefficient, and rho is the fluid density.

The spool control unit 120 receives the error value between the actuator flow rate Qset requesting operation of the electronic joystick 300 and the current actuator use flow rate Qscyl and outputs the error value to the first or second control valve 30, (40).

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 position of the first or second control valve 30 (40) described above is changed.

The pump control unit 200 controls the swash plate angle of the pump 10 so that it can be discharged only by the flow rate required by the working actuator.

The pump control unit 200 includes a discharge flow rate calculation unit 210 for predicting the 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

Qpump: Required flow rate of the pump, Qset: Required flow rate value generated by control of the electronic joystick, and Qregen: Flow rate regenerated.

The discharge flow rate calculation unit 210 calculates the current pump discharge flow rate by using the following equation (3) based on the detection value of the swash plate angle detection unit 11 and the detection value of the engine speed detection unit 21.

Where Qspump is the current discharge flow, ω is the engine speed, and Δv 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 12 of the pump 10 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 converted to a control signal (supply current) through the electronic proportional pressure valve driving 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 50 that drives the arm and may correspond to the second actuator 60 that drives the boom.

The above-described first actuator 50 drives the arm and uses the regeneration flow rate when the first actuator 50 is driven to extend, which will be described with reference to FIG.

The flow amount of the rod side of the first actuator 50 is discharged by its own weight when the arm is retracted.

This flow passes through the main spool Aout of the first control valve 30 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 pressure on the cylinder head side of the first actuator 50 because the speed is controlled through the meter-out control.

Therefore, a part of the flow rate on the rod side is combined with the pump flow rate through the check valve 33 formed in the first internal flow path 32 and supplied to the cylinder head of the first actuator 50.

The regeneration flow rate Qregen used in the above-described first actuator 50 can be calculated by the following equations (4) and (5).

Where: Qregen: regeneration flow rate, Aregen: regeneration valve (check valve) flow area, P *: pressure between spool and regeneration release circuit, Ppump: pump discharge pressure, Cq: flow coefficient, Ahead: Arm cylinder load area to head area ratio, Qscyl: Actuator used flow rate, Aout: Spool opening area connected to the tank from the actuator, and Prod: Load pressure on the arm rod side.

In addition, a regeneration flow rate is generated when the boom is loaded, which will be described with reference to FIG.

The second actuator 60 is regenerated to the boom rod side through the check valve 43 formed in the second internal flow passage 42 by a part of the flow rate of the head side due to its own weight when the boom descends, Can be calculated by the following equation (6). &Quot; (6) "

Here, Qregen: regeneration flow rate, Aregen: regeneration valve (check valve) flow area, Ppump: pump discharge pressure, Cq: flow coefficient, rho: fluid density, Phead: load pressure on the boom head side.

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 driven by the pump, Qset is the required flow rate required by the control of the electronic joystick, and Qregen is the regeneration flow rate generated in the first or second actuator 50 (60).

As described above, the control unit C calculates the detection value obtained from each of the detection units and controls the first or second control valve 30 (40) and the pump 10 to discharge the optimum flow rate corresponding to the required flow rate .

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 an embodiment of the present invention can be used in construction equipment. In particular, it is possible to regenerate the hydraulic pressure naturally generated in the actuator in which the potential energy acts, .

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

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

3 is an exemplary view for explaining a control unit in an electrohydraulic system of a construction equipment according to an embodiment of the present invention.

FIGS. 4 and 5 are diagrams for explaining calculation of a flow rate when an actuator for a work is driven in an electrohydraulic system of a construction equipment according to an embodiment of the present invention.

DESCRIPTION OF THE REFERENCE NUMERALS (S)

10: pump 11: swash plate angle detector

12: Discharge hydraulic pressure detecting unit 20: Engine

21: engine speed detecting unit 30, 40: first and second control valves

31, 41: First and second spool position detecting portions 35:

50, 60: first and second actuators

51, 61: First and second head side pressure detecting portions

52, 62: first and second rod-side pressure detecting portions

100: valve control unit 110: actuator use flow rate calculation unit

120: spool control unit 130: first electronic proportional pressure reducing valve drive unit

200: pump control unit 210: discharge flow rate calculation unit

220: Swash plate control unit 230: Second electronic proportional pressure reducing valve drive unit

300: electronic joystick C:

Claims (3)

A pump (10) capable of varying the discharge flow rate of the working oil and supplying operating fluid to an actuator connected to the working device; (30, 40) for controlling a flow path of the working oil supplied to the actuator, wherein when the working device connected to the actuator is driven by one of self weight and inertia, the head side of the actuator A regeneration circuit for connecting a rod-side hydraulic line and supplying a part of the hydraulic fluid discharged from one of the head side and the rod side of the actuator to the other one of the head side and the rod side of the actuator; Calculating a discharge oil pressure measurement value of the pump and an opening amount measurement value of the control valve, and calculating a regeneration flow rate (Qregen) supplied to the actuator by the regeneration circuit unit An actuator use flow rate calculation unit 110; A swash plate control unit 220 for calculating the swash plate angle of the pump so that the hydraulic oil is discharged by a difference of the regeneration flow rate Qregen from a required flow rate Qset input by a joystick operation of the driver; And An electronic proportional pressure reducing valve driver 230 for controlling the swash plate angle of the pump 10 based on the result determined by the swash plate controller 220; And an electromagnetic hydraulic system of the construction equipment. The method according to claim 1, A detection value for detecting the swash plate angle of the pump in operation, a detection value for detecting the rotation number of the pump, and a detection value for detecting the discharge pressure of the hydraulic oil discharged by the pump, And a discharge flow rate calculation unit 210 for calculating a discharge flow rate Qspump, The swash plate control unit, Calculating a swash plate angle of the pump from which the remaining flow rate excluding the regeneration flow rate (Qregen) and the discharge flow rate (Qspump) can be further discharged from the pump at the required flow rate (Qset); The electronic hydraulic system of construction equipment is characterized by. 3. The method of claim 2, The opening amount of the control valve is calculated by calculating the spool position of the control valve measured by the first and second spool position detecting portions (31, 41) The rotational speed of the pump is calculated by calculating the rotational speed of the engine detected by the engine speed detecting unit 21; The electronic hydraulic system of construction equipment is characterized by.

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