JPH0489934A - Hydraulic drive device of civil engineering/construction machine - Google Patents

Abstract

PURPOSE:To reduce the manufacturing cost by individually controlling the magnitude of a control pressure, which is given to No.1 pilot valve from a decompressing means, and the magnitude of a control pressure given to No.2 pilot valve from decompressing means. CONSTITUTION:When a control lever 2 is turned in the S1 direction, an electric signal is read into the operational part of a controller 3 via a signal wire 6a. The operational part gives signal to solenoid selector valves 5i, 5o and emits control current to solenoid proportioning decompression valves 4i, 4o via signal lines 7i, 7o so as to generate respective control pressures. The control pressure led through a meter-in pilot line 15i is given to No.1 pilot valve 9aip of No.1 flow control valve 9ai so as to displace No.1 main seat valve 9aiS. The control pressure led through a meter-out pilot line 150 is given to No.2 pilot valve 9aop so as to displace No.2 main seat valve 9aos.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a hydraulic drive system for civil engineering/construction machinery such as a hydraulic excavator, and in particular, a directional control valve that drives an actuator has a main seat valve and a main seat valve. The present invention relates to a hydraulic drive system for civil engineering and construction machinery, which is comprised of a flow control valve consisting of a pilot valve that controls the operation of the machine.

[Conventional technology]

FIG. 3 is a circuit diagram showing an example of this type of conventional hydraulic drive system for civil engineering and construction machinery. In this conventional technology, the hydraulic power source 1
2, an actuator 14 driven by pressure oil supplied via the main pipe 13 of the hydraulic source 12, and the hydraulic source 1.
The actuator 14 includes a directional switching valve 11 that controls the flow of pressure oil supplied from the actuator 2 to the actuator 14, and a hydraulic pilot operating device 24 that controls the driving of the directional switching valve 11.

This hydraulic pilot operating device 24 includes an operating lever 21,
and a hydraulic remote control valve 20 including pressure reducing means, that is, pressure reducing valves 22a and 22b, which generate pilot pressure according to the operation of the operating lever 21, and pilot pipes that guide the pilot pressures generated by the pressure reducing valves 22a and 22b to the direction switching valve 11, respectively. 23a and 23b. In addition, the above-mentioned directional switching valve 11 includes four poppet two flow control valves,
That is, the first flow control valve 9 arranged on the meter-in side
ai.

10bi, second flow control valves 9ao and 10bo arranged on the meter-out side, and when the actuator 14 is contracted, the first flow control valve 9ai and the second flow control valve 9
ao operate in pairs, and when the actuator 14 is extended, the first flow control valve 10bi and the second flow control valve 10
bo operates in pairs. Further, each of the first flow control valves 9ai and 10bi is a first main seat valve 9ai.
s, 10bis and the first pilot valve 9 a i p
, 10bip, and the second flow control valves 9ao, 10
each of bo is a second main seat valve 9aos, 10bo
s and second pilot valves 9aop and 10bop. The first pilot valve 9a ip of the first flow rate control valve 9ai is actuated by the control pressure applied via the pilot pipe 23a described above, thereby opening the first main seat valve 9ais. The second pilot valve 9aop of the flow rate control valve 9ao is operated to open the second main seat valve 9aos, and the control pressure applied via the pilot pipe 23b described above opens the first flow rate control valve 10bj. The first main seat valve 10bis is opened by the operation of the first pilot valve 10bip of the second flow control valve 10bo, and the second main seat valve 10bis is opened by the operation of the second pilot valve 10bop of the second flow rate control valve 10bo by the city control pressure. Valve 10. bo-s opens.

The above-described flow control valves 9ai, 9ao, and 10bi.

Each of the 10bO's is organized into an equivalent basic structure. Although FIG. 4 is a longitudinal sectional view showing the structure of the flow control valve 9ai, the other flow control valves 9ao, 10bi, and 10bo have the same structure. Flow control valve 9 shown in FIG.
ai connects or cuts off the passage between an inflow port 32 connected to the main pipe line 13 connected to the hydraulic power source 12 and an outflow port 33 connected to the rod side of the actuator 14 in the main body 31; Multiple slits 35 in the part
The main seat valve 9ais has the above-mentioned main seat valve 9ais, and
A sub-casing 41 that contacts the main body 31 is provided with the aforementioned pilot valve 9a ip that operates the main seat valve 9ais and a spring 40 that biases the pilot valve 9a ip in the direction of the main seat valve 9ais. Further, the main body 31 is formed with a back pressure chamber 36 that communicates with the inflow boat 32 via the slit 35 of the main seat valve 9ais.
1 and the subcasing 41 have an auxiliary passage 38 that can communicate the back pressure chamber 36 and the outflow boat 33, and the above-mentioned pilot valve 9aip communicates or cuts off the auxiliary passage 38. Further, the sub-casing 41 is formed with a control pipe 39 that communicates with the pilot pipe 23a of the hydraulic pilot operating device 24 described above and guides the control pressure for driving the pilot valve 9aip.

This flow rate control valve 9ai operates when control pressure is introduced into a pressure chamber formed in the sub casing 41 and the piston portion of the pilot valve 9aip via the control pipe 39, and this control pressure causes the pilot valve 9aip to move into the fourth pilot valve 9aip. The pilot valve 9a ip is displaced upward in FIG. 4 until it reaches an equilibrium position between the force that moves it upward in the figure and the force exerted by the spring 40 that urges the pilot valve 9a ip to move upward in FIG. 4. , an auxiliary passage 38 communicating from the back pressure chamber 36 to the outflow port 33 opens. Therefore, a flow of pressure oil is generated from the inflow boat 32 to the back pressure chamber 36 via the slit 35, and the flow rate passing through the slit 35 and the flow rate from the back pressure chamber 36 to the auxiliary passage 38 are increased.
The amount of movement of the main seat valve 9ais can be controlled by balancing the flow rate with the pilot valve flow rate that reaches the outflow boat 33 via the main seat valve 9ais.

That is, by controlling the pilot valve 9aip, the amount of displacement, that is, the amount of opening of the main seat valve 9ais can be controlled, and the flow rate flowing from the inflow boat 32 to the outflow port 33 can be controlled.

The operation of the conventional hydraulic drive system shown in FIG. 3 having such a directional control valve 11 is as follows.

For example, if the operating lever 21 is operated a predetermined amount toward the Sl side in FIG.
Of the pressure reducing valves 2a and 22b, the pressure reducing valve 22a is operated to generate pilot pressure, that is, control pressure. This control pressure is applied to the first pilot valve 9a ip of the first flow control valve 9ai and the second flow control valve 9 through the pilot pipe 23a.
ao and the second pilot valve 9aop, thereby operating the first pilot valve 9aip and the second pilot valve 9aop, respectively, and operating the first main seat valve 9ais and the second main seat valve 9a. .

S opens each valve. Accordingly, the pressure oil of the hydraulic source 12 flows from the main pipe line 13 through the first seat valve 9ais to the A boat of the actuator 14, and at the same time flows from the B port of the actuator 14 through the second main seat valve 9aos to the tank. Pressure oil flows through the actuator 1.
4 contracts. Moreover, if the operating lever 21 is operated by a predetermined amount toward the side 82 in FIG. 3, contrary to the above, the pressure reducing valve 22b of the hydraulic remote control valve 20 is activated, and a control pressure is generated. This control pressure is applied to the first pilot valve 10bi of the first flow rate control valve 10bi via the pilot circuit 23b.
p, and a second flow control valve 10b.

and a second pilot valve 10 bop,
As a result, the first pilot valve 10 b ip, the second
The pilot valves 10bop each operate, and the first main seat valve 10bis and the second main seat valve bos each open. Along with this, the pressure oil of oil pressure #12 is transferred to the main pipe 1
3 to the B port of the actuator 14 via the first main seat valve 10bis, and at the same time the actuator 1
Pressure oil flows from the A port of the actuator 14 to the tank via the second main seat valve 10bos.
grows in the opposite way to the above.

[Problem to be solved by the invention]

However, the above-mentioned conventional technology has the following problems.

Now, if we assume that the hydraulic source 12 is P1 tank T, the A boat of actuator 14 is A, and the B boat is B, the flow of the pressure oil described above is shown. Using valves 9ai and 9ao, P-+B and A→T
uses flow control valves 1゜bi and 10bo, and the flow of pressure oil is controlled individually for each flow control valve, but the same control pressure is applied to each flow control valve seal. Therefore, it is difficult to control the meter-in side flow control valve and the meter-out side flow control valve independently from each other, which constitute a pair of valve seals.

In other words, in civil engineering and construction machinery such as hydraulic excavators, the actuator operation feeling (generally called metering characteristics) is as shown in Fig. 5 (a) for the flow of P-+A and B-+T. P
For example, the characteristics shown in FIG. 5(b) are required for the flow of -+B and A-+T. Moreover, this is just 1
Although only one actuator 14 has been described, a plurality of hydraulic actuators are typically provided, and each hydraulic actuator typically has different desired metering characteristics. Therefore, in the prior art, in situations where these various metering characteristics are not actually obtained, in order to ensure the metering characteristics, the opening area of the main seat valve of the flow control valve constituting the directional control valve is The design of each characteristic must be changed individually, which is extremely troublesome.

Alternatively, in order to ensure such metering characteristics, it is conceivable to respond by changing the pressure characteristics applied to the operating lever 21. For example, if the control pressure output characteristic of the pressure reducing valve 22a is adapted to the first flow rate control valve 9ai in the one shown in FIG. 3, the first main seat valve 9ais for the first flow control valve 9ai Although it is not necessary to make design changes such as
.

In consideration of the control pressure output characteristics adapted to the first flow rate control valve 9ai, the second main seat valve 9aos
requires more difficult design changes such as

As described above, in the conventional technology, a huge amount of time and manufacturing costs are spent on setting the actuator operation feeling, and there is a problem in independent controllability of meter-in and meter-out.

The present invention has been made in view of the above-mentioned actual situation in the prior art, and its object is to provide a directional control valve having a plurality of flow control valves each consisting of a main seat valve and a pilot valve for controlling the main seat valve. Therefore, it is an object of the present invention to provide a hydraulic drive device for civil engineering and construction machinery that can ensure independent controllability of each of a pair of flow control valves without requiring a design change of a main seat valve or the like.

[Means to solve the problem]

To achieve this objective, the present invention provides a hydraulic source, an actuator driven by pressure oil supplied from the hydraulic source, and a directional control valve that controls the flow of the pressure oil supplied from the hydraulic source to the actuator. A hydraulic pilot operating device includes a control lever and a pressure reducing means for outputting a control pressure for driving a directional control valve in accordance with the operation of the control lever, and the directional control valve is connected to a first main seat valve and a first main seat valve. a first flow control valve disposed on the meter-in side including a first pilot valve that controls the operation of the main seat valve; a second main seat valve and a second flow control valve that controls the operation of the second main seat valve; and a second flow control valve disposed on the meter-out side, and the control pressure output from the pressure reducing means is equal to or lower than each of the first flow control valve and the second flow control valve. In a hydraulic drive system for civil engineering and construction machinery, the control pressure is applied as the driving pressure to the first pilot valve and the second pilot valve, and the control pressure is applied from the pressure reducing means to the first pilot valve of the first flow control valve; This configuration includes a control means for individually controlling the magnitude of the control pressure applied from the pressure reducing means to the second pilot valve of the second flow rate control valve.

[For production]

The present invention uses the above-mentioned control means to control the pressure reduction means from the first to
The magnitude of the control pressure given to the first pilot valve of the flow control valve and the magnitude of the control pressure given to the second pilot valve of the second flow control valve are individually controlled, and these control pressures can be set in advance by taking into consideration the opening amounts of the first main seat valve and the second main seat valve in order to realize a desired operating form of the actuator,
It is possible to ensure independent controllability of the pair of flow rate control valves, and the control means is capable of differentiating the control pressures guided from the pressure reducing means to the first pilot valve and the second pilot valve, respectively. Therefore, the independence of the first and second flow control valves forming the pair can be ensured without requiring a design change of the main seat valve or the like constituting the flow control valve.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of a hydraulic drive system for civil engineering and construction machinery according to the present invention will be described based on the drawings.

FIG. 1 is a circuit diagram showing an embodiment of a hydraulic drive system for civil engineering and construction machinery according to the present invention. This FIG. 1 is drawn in a similar manner to FIG. 3 described above. That is, even in the embodiment shown in FIG. 1, a hydraulic power source 12 equivalent to the prior art shown in FIG. and a directional switching valve 11 that controls the flow of pressure oil supplied from the hydraulic source 12 to the actuator 14. The directional control valve 11 includes four poppet-type flow control valves similar to those shown in FIG. Consisting of two flow control valves 9ao and 10bo,
The first flow control valves 9ai and 10bi are the first main seat valves 9ais and 10bis and the first pilot valve 9, respectively.
aiP, 10 bip, a second flow control valve 9ao,
10bo are second main seat valves 9a.

S, 10bos and second pilot valve 9aop.

10 bop, and each flow control valve 9a
The basic structure of i, 10bi, 9ao, and 10bo is the same as that shown in FIG. 4 described above.

The hydraulic pilot operation device 1 that drives the directional control valve 11 has an electric operation lever 2 that outputs an electric signal, and a pressure reduction means that generates a control pressure is an electromagnetic proportional pressure reduction valve 4i, 4o. , an electromagnetic switching valve 51 that selectively supplies the control pressure generated by the electromagnetic proportional pressure reducing valve 41 to either of the first pilot valves 9aip, 10bip of the first flow rate control valves 9ai, 10bi, and the electromagnetic proportional pressure reducing valve 4.
The control pressure generated at 0 is transferred to the second flow control valve 9a.

An electromagnetic switching valve 50 is provided to selectively supply either the 10bo second pilot valve 9aop or the 10bop. The above electromagnetic switching valve 51 supplies the control pressure guided through the meter-in pilot line 15i to either the first pilot valve 9aiP or 10bip via either the meter-in drive control pressure line 9i or 101. death,
In addition, the electromagnetic switching valve 50 is connected to the meter-out pilot line 15.
The control pressure guided through the meter-out drive control line 9o, 10o is supplied to one of the second pilot valves 9aop, 10bop.

Then, the operating lever 2 and the electromagnetic proportional pressure reducing valve 4i.

40, from the electromagnetic proportional pressure reducing valve 41 to the first flow control valve 9
ai, 10bi first pilot valve 9aip, 10b
The magnitude of the control pressure given to ip and the second pilot valve 9aop of the electromagnetic proportional pressure reducing valve 4o to the second flow control valve 9ao and 1Qbo.

It is provided with control means, for example, a controller 3, which individually controls the magnitude of the control pressure applied to 10 bop. This controller 3 includes an input section for inputting a signal corresponding to the amount of operation of the operating lever 2, and an input section that inputs a signal corresponding to the operating amount of the operating lever 2, and
A desired relationship between the operation amount of Uru operation lever 2
a storage section that stores the relationship between the amount of operation of the operating lever 2 and the flow rate; a calculation section that reads out the relationship stored in this storage section and calculates the flow rate according to the amount of operation of the operating lever 2; The controller 3 includes an output section that outputs a corresponding signal to the electromagnetic proportional pressure reducing valves 4i, 4o, and outputs a selection signal for driving the electromagnetic switching valves 5i, 5o.

The operating lever 2 and the controller 3 are arranged so that the operating lever 2 is 31
Signal line 6 that sends an electric signal when the operating lever is moved in the direction
a and a signal line 6b that sends an electric signal when the operating lever 2 is operated in the S2 direction.The controller 3 and the electromagnetic proportional pressure reducing valves 4i and 4o are connected to the operating lever 2.
is operated, the first flow control valves 9ai, 10bi
A signal line 71 that sends an electric signal to drive and control the first pilot valves 9aip and 10bip, and the second flow control valve 9
ao, 1Qbo second pilot valve 9a.

The controller 3 and the electromagnetic switching valve 5i are connected by a signal line 7o that sends a signal to drive and control the P and 10bop.
, 5o are connected by a signal line 8, and by this signal Ia8, when the operating lever 2 is operated in the 31 direction, a signal is output to keep the electromagnetic switching valves 5i and 5o in the state shown in FIG. 2 is operated in the 32 direction, a signal is output to switch the electromagnetic switching valve 51.5o to the right position in FIG.

Note that the relationship between the operation amount of the operating lever 2 and the flow rate passing through the main seat valve, which is stored in advance in the storage section of the controller 3 described above, is, for example, the first main seat valve 9ais of the first flow rate control valve 9ai. This is the relationship shown in the first quadrant of FIG. 2. In order to realize the relationship of the first quadrant in FIG. Output. Note that the second quadrant in FIG. 2 shows the characteristics of the flow rate flowing through the first main seat valve 9ais corresponding to the relationship in the first quadrant, and the third quadrant shows the characteristics of the flow rate flowing through the first main seat valve 9ais corresponding to the relationship in the second quadrant. The performance of the proportional pressure reducing valve 41 is shown, and the fourth quadrant corresponds to the performance of the electromagnetic proportional pressure reducing valve 41 shown in the third quadrant. Further, the relationship between the operating amount of the operating lever 2 and the first main seat valve 9ais shown in the first quadrant of FIG. 2 is made to match the flow rate characteristic at the time of PA shown in FIG. 5(a) described above. Although not shown, a relationship similar to that shown in FIG. 2 is established, that is, with respect to the second main seat valve 9aos of the second flow rate control valve 9ao, B- in FIG. 5(a) is established.
A corresponding relationship at time T is also established for the first flow control valve 10bi.
Regarding the first main seat valve 10bis, Fig. 5(b)
The corresponding relationship at P→B is also established for the second flow control valve 1.
Regarding the second main seat valve 10bos of 0bO, the relationship corresponding to the time A-+1 in FIG. 5(b) is stored in advance in the storage section of the controller 3.

The operation of the embodiment configured as described above is as follows.

For example, when the control lever 2 shown in FIG. 1 is operated in the direction 81, an electric signal corresponding to the amount of operation is read into the calculation section of the controller 3 via the input section of the controller 3 via the signal line 6a. The arithmetic unit determines that the operating lever 2 has been operated in the 31 direction, and accordingly, the signal line 8 is output from the output unit.
An electrical signal is outputted through the electromagnetic switching valves 5i, 5o to maintain them in the state shown in FIG. At the same time, controller 3
The calculation unit calculates the relationship between the operating lever 2 and the flow rate of the first main seat valve 9ais of the first flow rate control valve 9ai stored in the storage unit, that is, the relationship shown in FIG. ) and the second flow rate control valve 9
The relationship between the operating lever 2 and the flow rate related to the second main seat valve 9aos of the ao (the relationship at P-+1 in FIG. 5(a)) is read out, and the operation amount of the operating lever 2 input as described above is The corresponding flow rates are determined, and the electrical signals corresponding to these flow rates, that is, the electromagnetic proportional pressure reducing valve control current, are sent from the output section to the electromagnetic proportional pressure reducing valves 44, 44, 44, 44, 30, 30, 30, 32, 32 through signal lines 7i, 7o, respectively.
Output to each of 4o. As a result, the electromagnetic proportional pressure reducing valves 4i and 4o operate, and respective control pressures are generated. The control pressure guided through the meter-in pilot line 15i is given to the first pilot valve 9aip of the first flow rate control valve 9ai via the electromagnetic switching valve 51 and the meter-in drive control pressure line 91. The pilot valve 9aip of the cylinder 1 is actuated to open the first main seat valve 9a.
is is displaced, and the meter-out pilot line 15
The control pressure led through o, that is, the control pressure generated by the electromagnetic proportional pressure reducing valve 40 independently of the control pressure generated by the electromagnetic proportional pressure reducing valve 41 described above, is the control pressure led through the electromagnetic switching valve 50, the meter-out drive control pressure A second pilot valve 9a of a second flow control valve 9ao via a conduit 9o.

p, which causes the pilot valve 9 of the cylinder 2 to
aop is activated to open the second main seat valve 9a.

S is displaced. As a result, from the hydraulic source 12 to the main pipe line 13
The pressure oil supplied via the first main seat valve 9ais is given to the rod side of the actuator 14, and the return oil on the bottom side of the actuator 14 is supplied to the second main seat of the second flow control valve 9ao. It flows into the tank via the valve 9aos and the actuator 14 contracts. In this case, the first
The control pressure given to the pilot valve 9a ip is P
l, the control pressure given to the second pilot valve 9aop is P2, and the flow rate flowing through the first main seat valve 9ais is Q.
l, the differential pressure at the throttle of this first main seat valve 9ais is ΔP
1. The flow rate flowing through the second main seat valve 9aos is C2, and the differential pressure at the throttle of this second main seat valve 9aos is ΔP Z
, the flow coefficient is C1, and the proportionality constant is K, then Q, = C-K (τ below, ・P.

Q, = C-K (τT2 ・P2 It is expressed as

Similarly, when the control lever 2 is operated in 32 directions, an electric signal corresponding to the amount of operation is read into the calculation section of the controller 3 via the input section of the controller 3 via the signal line 6b. The calculation section determines that the operating lever 2 has been operated in the direction 52, and an electric signal is output from the output section via the signal line 8 to switch the electromagnetic switching valve 51, 50 to the right position in FIG. be done. At the same time, the calculation section of the controller 3 calculates the first flow rate control valve 10 stored in its storage section.
Operation lever 2 related to the first main seat valve 10bis of bi
The relationship between and the flow rate, that is, the relationship at PI3 in Fig. 5(b),
and the second main seat valve 10 of the second flow control valve 10bO
Read the operation amount of the operation lever 2 related to BOS and the flow rate, that is, the relationship from A to T in FIG. , outputs an electric signal corresponding to these flow rates, that is, an electromagnetic proportional pressure reducing valve control current, from its output portion to each of the electromagnetic proportional pressure reducing valves 41 and 40 via signal lines 7i and 7o. As a result, the electromagnetic proportional pressure reducing valves 4i and 4o operate, and mutually independent control pressures are generated.

These control pressures are applied to the first pilot valve 1 as described above.
0bip, given to the second pilot valve 10bop;
As a result, the pilot valve 10 bip and the second pilot valve 10 bop of the box 1 are operated, and accordingly, the first main seat valve 10 bis and the second main seat valve 10 bop are operated. Therefore, the pressure oil from the hydraulic source 12 is transferred to the main pipe 13.
, the return oil is supplied to the bottom side of the actuator 14 via the first main seat valve 10bis, and the return oil is supplied from the rod side to the second main seat valve 10bis.
main seat valve 10b.

S is returned to the tank, and the actuator is extended.

In the embodiment configured in this way, FIG. 5(a),
(b) The desired metering characteristics of the actuator 14 can be obtained according to the setting relationship of the controller 3, that is, the desired metering characteristics of the actuator 14 illustrated in FIG.
The electromagnetic proportional pressure reducing valves 4i and 4o can be operated by the signal output based on the relationship between the operating amount of the operating lever 2 and the flow rate set in , and control pressures independent of each other can be generated. Main seat valves 9a of flow control valves 9ai, 9ao, 10bi, and 10bo that constitute 11
The independent controllability of the paired flow control valves can be ensured without requiring design changes to the opening area characteristics of is, 9aos, 10bis, 1Obos, etc., and desired metering characteristics can be obtained extremely easily.

In addition, the electromagnetic proportional pressure reducing valve 41 and the first flow control valve 9ai,
10bi first pilot valve 9aip.

One electromagnetic switching valve 51 is provided between 10 bip, and another electromagnetic switching valve 5o is provided between the electromagnetic proportional pressure reducing valve 4o and the second flow control valves 9ao and 10bo to control the directional switching valve 11. Therefore, there is no waste compared to the case where an electromagnetic switching valve is provided for each flow control valve, and the device configuration can be simplified.

Note that although the above embodiment illustrates the driving of one actuator 14, civil engineering/construction machines such as hydraulic excavators are provided with a plurality of actuators, and in such cases, the directional control valve is also used. The desired metering characteristics can be secured by setting the relationship between the operation amount of the operating lever 2 of the controller 3 and the flow rate without requiring any design changes to the main seat valve of the flow control valve 11, etc., and the above-mentioned effects are further improved. become remarkable.

〔Effect of the invention〕

Since the hydraulic drive device for civil engineering and construction machinery of the present invention is configured as described above, it is equipped with a directional control valve having a plurality of flow control valves each consisting of a main seat valve and a pilot valve that controls the main seat valve. In other words, it is possible to ensure independent control of each of the flow control valves in a pair according to the setting relationship of the controller without requiring any design changes to the main seat valve, etc., compared to the conventional method. This has the effect of reducing production costs.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing an embodiment of the hydraulic drive system for civil engineering and construction machinery of the present invention, FIG. 2 is a diagram showing characteristics set by a controller included in the embodiment shown in FIG. 1, and FIG. Fig. 3 is a circuit diagram showing an example of a conventional hydraulic drive device for civil engineering and construction machinery, and Fig. 4 is a vertical cross section showing the configuration of a flow control valve included in a directional switching valve provided in the hydraulic drive device shown in Fig. 3. 5(a) and 5(b) are diagrams showing desired flow control valves of the actuator provided in the hydraulic drive device shown in FIG. 3. 1... Hydraulic pilot operating device, 2...
......Operating lever 3...Controller, 4i, 4o......Electromagnetic proportional pressure reducing valve (pressure reducing means), 5i, 5o... ...Solenoid switching valve, 6a, 6b, ? i, 7o, 8...
Signal line, 9j...Meter-in drive control pressure line, 9o...Meter-out drive control pressure line, 9ai...1st Flow rate control valve, 9ais...First main seat valve, 9a
ip・・・・・・First pilot valve, 9ao
......Second flow control valve, 9a. S......Second main seat valve, 9aop...
......Second pilot valve, 10i...
...meter-in drive control pressure pipe, 10o...
・・・・・・Meter-out drive control pressure pipe, 10bi・
......First flow control valve, 10bis...
...First main seat valve, 10bip...
...First pilot valve, 10bo...
...20th flow control valve, 10bos...
2nd main seat valve, 10bop...2nd
pilot valve, 11... directional valve,
12......Hydraulic power source, 13......
・Main pipeline, 14... Actuator, 1
5i・・・・・・Meter-in pilot pipe, 1
5o・・・・・・Meter out pilot conduit. Figure 1112/ = Oil fE non-pilot operator ← I'\Amo12 P creator - 3 controllers 4i, 4o: tgLtyl mE4F-(1<F;
912) 5i, 5o: DenjAτManto-to9σis:)! -1's 1 sheet 1,000 bis #-1's main sheet operator tobos 4 Gagan sea 1-f- / 0bOp: 42t>tXsror/to卆/ /;
”,”I1tnku+! '! ! +/2゛E person 13 standing distance Fig. 1 Fig. 4 Fig. 5 P-A (9oi) (b Lever iL Lever 1LL

Claims (4)

[Claims] (1) A hydraulic source, an actuator driven by pressure oil supplied from the hydraulic source, a directional switching valve that controls the flow of the pressure oil supplied from the hydraulic source to the actuator, an operating lever, and its operation. A hydraulic pilot operating device includes a pressure reducing means that outputs a control pressure for driving the directional control valve in response to actuation of a lever, and the directional control valve includes a first main seat valve and a first main seat valve. A first flow control valve disposed on the meter-in side including a first pilot valve that controls the operation of the valve, a second main seat valve, and a second pilot that controls the operation of the second main seat valve. a second flow control valve disposed on the meter-out side, and the control pressure output from the pressure reducing means is equal to or lower than the first flow control valve of each of the first flow control valve and the second flow control valve. In a hydraulic drive system for civil engineering and construction machinery, the control pressure is applied from the pressure reducing means to the first pilot valve of the first flow rate control valve. , a hydraulic drive system for civil engineering and construction machinery, characterized in that a control means for individually controlling the magnitude of the control pressure applied from the pressure reducing means to the second pilot valve of the second flow rate control valve is provided. . (2) The hydraulic drive device for civil engineering/construction machinery according to claim (1), wherein the operating lever is an electric operating lever that outputs an electric signal. (3) The pressure reducing means is an electromagnetic proportional pressure reducing valve, and the control means controls the desired relationship between the operating amount of the operating lever corresponding to the actuator and the flow rate flowing through the first main seat valve and the second main seat valve. 2. The controller according to claim 2, wherein the controller stores a flow rate in advance, calculates a corresponding flow rate according to the amount of operation of a control lever, and outputs a signal corresponding to the flow rate to the electromagnetic proportional pressure reducing valve. Hydraulic drive equipment for civil engineering and construction machinery. (4) The directional control valve has two pairs consisting of a first flow rate control valve and a second flow rate control valve, and the control pressure output from the pressure reducing means is applied to the first flow rate forming one pair. a first pilot valve of the control valves, and a first forming the other pair of control valves;
a first switching means for selectively supplying the control pressure outputted from the pressure reducing means to either one of the first pilot valves of the flow control valves; and a second flow control valve forming the pair; and the second pilot valve of the second flow control valves forming the other pair, and the control pressure is applied via the first switching means. and second switching means for selectively supplying the first flow control valve to the second pilot valve of the second flow control valve included in the same pair as the first flow control valve including the pilot valve. Civil engineering/as described in any of (1) to (3)
Hydraulic drive system for construction machinery.