WO2000065239A1

WO2000065239A1 - Method and apparatus for controlling construction machine

Info

Publication number: WO2000065239A1
Application number: PCT/JP2000/002441
Authority: WO
Inventors: Kimimasa Onda
Original assignee: Shin Caterpillar Mitsubishi Ltd.
Priority date: 1999-04-26
Filing date: 2000-04-14
Publication date: 2000-11-02
Also published as: JP2000309952A; JP3629382B2

Abstract

An apparatus for controlling a construction machine is provided for improving work efficiency when a hydraulic actuator is free-falling, so that it decreases power loss, improves fuel economy, decreases thermal loss and improves cooling performance. The apparatus comprises hydraulic pumps (51, 52) driven by an engine to remove hydraulic fluid from a tank, a hydraulic actuator driven by the hydraulic fluid discharged by the hydraulic pumps, a channel through which hydraulic fluid is sent from the hydraulic actuator to the tank, a control valve (60, 64) arranged in the channel to control the flow rate of the hydraulic fluid running through the channel, an engine speed sensor (71) for detecting rotational speed of an engine, and control means (1) for controlling the control valve to adjust the opening of the channel based on the input from a manipulator (54). The control means controls the control valve in accordance with the engine speed detected by the engine speed sensor.

Description

Description Control device and control method for construction machinery

The present invention relates to a control device and a control method for a construction machine, which control the operation of a hydraulic machine such as a boom cylinder and a stick cylinder in the construction machine. Background art

In general, a construction machine such as a hydraulic excavator includes an upper rotating body 102, a lower traveling body 100, and a working device 118 as shown in FIG. The undercarriage 100 has a right track 100R and a left track 100L that can be driven independently of each other, while the upper revolving structure 102 has a lower track 100 On the other hand, it is provided so as to be pivotable in a horizontal plane.

The working device 118 mainly includes a boom 103, a stick 104, a bucket 108, and the like, and the boom 103 rotates with respect to the upper rotating body 102. It is pivoted as much as possible. A stick 104 is connected to the tip of the boom 103 so as to be rotatable in the same vertical plane.

A boom drive hydraulic cylinder (boom cylinder, hydraulic actuator) 105 for driving the boom 103 is provided between the upper swing body 102 and the boom 103. At the same time, a hydraulic cylinder (stick cylinder, hydraulic actuator) 106 for driving the stick 104 is provided between the boom 103 and the stick 104. Also, between the stick 104 and the bucket 108, there is a bucket driving hydraulic cylinder (bucket) for driving the bucket 108. Cylinders and hydraulic actuators) 107 are provided.

Each of the cylinders 105 to 107 described above includes a hydraulic pump driven by an engine (mainly a diesel engine), a control valve for a boom, a control valve for a stick, a control valve for a bucket, and the like. A hydraulic circuit (not shown) having a plurality of control valves is connected, and hydraulic oil of a predetermined hydraulic pressure is supplied from a hydraulic pump via each control valve, and according to the hydraulic pressure supplied in this manner. It is designed to be driven.

With such a configuration, the boom 103 is in the directions a and b in the figure, the stick 104 is in the directions c and d in the figure, and the bracket 107 is in the direction e in the figure. And f is rotatable. The rotation of the boom 103 in the direction b in the figure is called boom down, and the rotation of the stick 104 in the direction d in the figure is called stick-in.

The operating room 101 has left and right levers as operating members for controlling the operation of the hydraulic excavator (running, turning, boom turning, stick turning, and bucket turning). , Left pedal, right pedal, etc. are provided.

Then, for example, when the operator operates these operating members such as levers and pedals, each control valve of the hydraulic circuit is controlled, and each cylinder 105 to 107 is driven. 03, stick 104 and bucket 108 can be rotated.

In addition, a pilot hydraulic circuit is provided to control each control valve. As a result, to operate the boom 103 and the stick 104, operate the boom operating member ゃ stick operating member in the operator's cab 101. The pilot hydraulic pressure is applied to the boom through the pilot oil passage. Control valve ゃ Acts on the stick control valve to drive the boom control valve and the stick control valve to the required positions. As a result, the boom drive hydraulic cylinder 1 0 5 Supply and discharge of hydraulic oil to and from the hydraulic cylinders 106 are controlled, and these cylinders 105 and 106 are driven to expand and contract to the required length.

As described above, in the hydraulic excavator, the excavation work and the like are performed by driving the working devices 1 18 such as the booms 103 and the sticks 104 by driving the cylinders 105 to 107 to expand and contract. Of various operations.

By the way, as one operation in such various operations, for example, there is a case where a stick-in in the direction d in FIG. 16 is performed. In this case, the stick 104 is driven as follows.

In other words, when the stick-in operation is performed and the stick 104 is lowered, the stick driving hydraulic cylinder 106 may be extended. In this case, the pilot oil pressure is applied to the stick control valve through the pilot oil passage. As a result, the spool position of the stick control valve becomes the stick lowered position, and the hydraulic oil from the hydraulic pump is supplied to one chamber of the stick driving hydraulic cylinder 106 through the oil passage. On the other hand, the hydraulic oil in the other room of the stick driving hydraulic cylinder 106 is discharged to the tank through the oil passage. As a result, the stick driving hydraulic cylinder 106 is extended, and the stick 104 is rotated downward as shown by the arrow d in FIG.

In this way, when the stick-in operation is performed, hydraulic oil is supplied to the stick driving hydraulic cylinder 106, but when the stick 104 is lowered, the stick driving hydraulic cylinder 106 is driven. Due to the gravity acting on the hydraulic cylinder 106, hydraulic oil is excessively discharged from the stick driving hydraulic cylinder 106, and the stick driving hydraulic cylinder 106 may drop more than necessary. Conceivable.

When lowering stick 104, stick drive hydraulic pressure Cylinder 106 drops its own weight in the direction of gravity, but its speed depends on the weight (stick 104, packet 108) acting on the hydraulic cylinder 106 for driving the stick. Weight and packet loading) and the amount of hydraulic oil discharged from the hydraulic cylinder 106 for stick drive. That is, the lowering speed of the stick 104 is determined by the size of the opening area of the oil passage (hydraulic oil discharge passage) between the stick driving hydraulic cylinder 106 and the reservoir tank.

For this reason, a throttle is interposed in the oil passage between the stick driving hydraulic cylinder 106 and the reservoir tank in order to prevent the stick driving hydraulic cylinder 106 from dropping sharply. Hydraulic oil discharged from the hydraulic cylinder 106 is prevented from being discharged to the reservoir tank more than necessary.

Similarly, when the boom 103 is lowered or the bucket 108 is lowered, gravity acts on the boom drive hydraulic cylinder 105 and the bucket drive hydraulic cylinder 107. The hydraulic cylinder between the boom drive hydraulic cylinder 105 and the reservoir tank will be unnecessarily lowered because the boom drive hydraulic cylinder 105 and the bucket drive hydraulic cylinder 107 will drop more than necessary.絞り Similarly, a throttle is interposed in the oil passage between the bucket driving hydraulic cylinder 107 and the reservoir tank, and the boom driving hydraulic cylinder 105 and the bucket driving hydraulic cylinder 107 are also provided. The hydraulic oil discharged from 7 is not discharged to the reservoir tank more than necessary.

The diameter of these throttles is particularly low when the engine speed is low and the pump discharge flow rate is low, so that each cylinder communicates with the reservoir tank so that hydraulic oil is not excessively discharged from the cylinders 105 to 107. The opening area of the oil passage (hydraulic oil discharge passage) is set to be small.

For example, the stick drive hydraulic cylinder 106 and the reservoir tank When the stick drive hydraulic cylinder 106 is lowered using gravity when stick-in operation is performed, the diameter of the throttle interposed in the oil passage between The back pressure acting to push back the hesitic hydraulic cylinder 106 in the direction opposite to the direction of gravity drop of the cylinder 106 is about 40 kgf / under the specified reference load (load) condition. It is set to be about cm ² .

As a result, even when the engine speed is low and the pump discharge flow rate is low, each cylinder descends more than necessary, creating a negative pressure (vacuum) in each cylinder, thereby causing cavitation. However, noise and vibration are prevented from being generated.

However, the diameters of these throttles are fixed and, as shown in Fig. 17, regardless of the engine speed, the hydraulic oil in the oil passage between the stick drive hydraulic cylinder 106 and the reservoir tank The opening area of the discharge passage is constant.

For this reason, when the engine rotation speed increases and the pump discharge flow rate increases, these throttles cause resistance loss, and the back pressure acting on each cylinder gradually increases, resulting in a smooth stick 104 There is a problem that the work efficiency is deteriorated because a stable descent is prevented.

In general, in order to lower the stick drive hydraulic cylinder 106 using gravity during stick-in operation, a predetermined pressure (about 40 kgf Z cm ² ) is applied to the stick drive hydraulic cylinder 106. However, as shown in Fig. 18, when the engine rotation speed increases and the pump discharge flow rate increases, the oil passage between the hydraulic cylinder 106 for driving the stick and the reservoir tank increases. A resistance loss occurs due to the installed throttle, and back pressure (approximately 145 kgf Z cm ² ) acts on the hydraulic cylinder 106 for the stick drive, causing the hydraulic cylinder 106 for the stick drive to gravity. In order to lower the pressure while utilizing the pressure, extra pressure from the hydraulic pump (pump discharge pressure) corresponding to the back pressure shown in the following equation is required.

Pressure from hydraulic pump = (actual back pressure-predetermined pressure) X cylinder area ratio This is the same for the boom driving hydraulic cylinder 105 and the bucket driving hydraulic cylinder 107.

For this reason, extra engine horsepower is required to secure such pump discharge pressure, resulting in power loss, deterioration of fuel consumption, and heat loss. In addition, when the pressure in each cylinder increases, the temperature of each cylinder also increases, so that the cooling performance also decreases.

Also, in actual work, lifting and turning operations of the work implement 118 are involved, and in order to secure these speeds, normal operation is performed at the maximum engine speed, so the weight of the stick 104 etc. Excessive consumption of engine horsepower during the descent control will lead to a decrease in work efficiency, fuel consumption and heat balance.

The present invention has been made in view of such a problem, and aims to improve the working efficiency at the time of controlling the self-weight drop of the hydraulic actuator, reduce power loss, improve fuel efficiency, reduce heat loss, and improve cooling performance. It is an object of the present invention to provide a control device and a control method for a construction machine, which can be improved. Disclosure of the invention

The control device for a construction machine of the present invention is driven by an operating member operated by an operator, a hydraulic pump driven by an engine to discharge hydraulic oil in a tank, and a hydraulic oil discharged by a hydraulic pump. A control that controls the flow rate of hydraulic oil that is interposed in the hydraulic oil discharge passage, the hydraulic oil discharge passage that discharges hydraulic oil from the hydraulic oil pump to the tank, and the hydraulic oil discharge passage. Detects valve and engine speed An engine speed sensor; and control means for controlling a control valve to adjust an opening area of the hydraulic oil discharge passage based on an operation amount of an operation member, wherein the control means is detected by the engine speed sensor. The control valve is controlled in consideration of the engine speed.

In addition, a hydraulic oil supply passage for supplying hydraulic oil from the hydraulic pump to the hydraulic actuator is provided, and the opening area of the hydraulic oil discharge passage is detected by the engine rotation speed sensor with the maximum operation amount of the operating member. It is preferable that a setting is made such that when the engine rotation speed is at a maximum, a hydraulic oil having a flow rate corresponding to the maximum supply flow rate of the hydraulic oil supplied through the hydraulic oil supply passage is discharged through the hydraulic oil discharge passage.

Further, the control means may be configured to control the control valve so that the opening area of the hydraulic oil discharge passage decreases as the engine rotation speed detected by the engine rotation speed sensor decreases.

More preferably, the control means may be configured to correct the control amount for the control valve by a correction coefficient that decreases as the engine speed decreases.

Further, the control means may be configured to set the control amount of the control valve such that the opening area of the hydraulic oil discharge passage changes according to the engine speed.

In addition, a bypass passage is provided for returning hydraulic oil not supplied to the hydraulic actuator to the tank via the control valve to the tank, and the control valve is interposed in the bypass passage to adjust the opening area of the bypass passage. The control means sets a basic tilt angle control amount for controlling a basic tilt angle control amount for controlling the discharge flow rate from the hydraulic pump based on a characteristic substantially inversely proportional to the flow rate of the hydraulic oil in the bypass passage. When the operation amount of the setting means and the operation member is the maximum and the engine speed detected by the engine speed sensor is not the maximum And a tilt angle control amount correction means for correcting the basic tilt angle control amount set by the basic tilt angle control amount setting means so that the discharge flow rate from the hydraulic pump is maximized. Is preferred.

Also, the construction machine control method of the present invention includes an operation member operated by an operator, a hydraulic pump driven by an engine to discharge hydraulic oil in a tank, and a hydraulic pump discharged by a hydraulic pump. Hydraulic oil pump, a hydraulic oil discharge passage that discharges hydraulic oil from the hydraulic oil pump to the tank, and a hydraulic oil discharge passage that is interposed in the hydraulic oil discharge passage and controls the flow rate of hydraulic oil that is discharged through the hydraulic oil discharge passage. A construction valve comprising: a control valve; an engine speed sensor for detecting an engine speed; and control means for controlling the control valve to adjust an opening area of the hydraulic oil discharge passage based on an operation amount of an operation member. A control method, comprising: a detection step for detecting an engine speed by an engine speed sensor; and an engine speed detected in the detection step. And a control step of controlling the control valve by the control means.

Preferably, in the control step, when the operation amount of the operation member is the maximum and the engine rotation speed detected in the detection step is the maximum, the hydraulic oil supply passage that supplies the hydraulic oil from the hydraulic pump to the hydraulic actuator. The control valve is controlled such that the hydraulic oil at a flow rate corresponding to the maximum supply flow rate of the hydraulic oil supplied through the hydraulic oil discharge passage is discharged through the hydraulic oil discharge passage.

In the control step, it is also preferable that the control valve is controlled such that the opening area of the hydraulic oil discharge passage decreases as the engine rotation speed detected in the detection step decreases.

Further, in the control step, it is preferable that the control amount for the control valve is corrected by a correction coefficient that decreases as the engine rotation speed decreases. It is also preferable that in the control step, the control amount of the control valve is set such that the opening area of the hydraulic oil discharge passage changes in accordance with the engine speed.

In addition, a bypass passage is provided for returning hydraulic oil not supplied to the hydraulic actuator through the control valve to the tank, and the control valve is interposed in the bypass passage to adjust the opening area of the bypass passage. In the control step, a basic tilt angle control amount for controlling the discharge flow rate from the hydraulic pump is set based on a characteristic substantially inversely proportional to the flow rate of the hydraulic oil in the bypass passage, and the operation member is operated. When the amount is maximum and the engine rotation speed detected in the detection step is not maximum, it is also preferable to correct the basic tilt angle control amount so that the discharge flow rate from the hydraulic pump becomes maximum.

According to the control device and the control method for a construction machine of the present invention configured as described above, the excess horsepower consumption during the descent of the hydraulic actuator during its own weight reduction is reduced, so that power loss is reduced, fuel consumption is improved, and heat The loss can be reduced. Also, since the pressure in the hydraulic actuator does not increase and the temperature in the hydraulic actuator does not increase, the heat balance can be improved and the cooling performance can be improved. Furthermore, there is no need for extra horsepower because no extra back pressure is generated when the deadweight of Hydraulic Factory is lowered. Work efficiency is improved. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a control block diagram for explaining the self-weight drop control of a stick in the control device for a construction machine according to one embodiment of the present invention.

FIG. 2 is an overall configuration diagram of a control device for a construction machine according to one embodiment of the present invention. FIG. 3 is a schematic diagram for explaining a control valve of the control device for a construction machine according to one embodiment of the present invention.

FIG. 4 is a diagram showing a map associating an operation amount of an operation member and a basic control signal of a proportional pressure reducing valve in the control device for a construction machine according to one embodiment of the present invention.

FIG. 5 is a diagram showing a map in which the engine rotation speed and the control signal rate of the proportional pressure reducing valve are related in the control device for the construction machine according to the embodiment of the present invention.

FIG. 6 is a diagram showing a map in which the correction control signal and the spool stroke are related in the control device for the construction machine according to the embodiment of the present invention. FIG. 7 is a diagram showing the relationship between the spool stroke amount and the opening areas of the PC passage, the CT passage, and the bypass passage in the control device for the construction machine according to the embodiment of the present invention.

FIG. 8 is a diagram showing control characteristics of the CT opening area according to the engine rotation speed in the control device for a construction machine according to one embodiment of the present invention. FIG. 9 is a diagram illustrating a modification of the control characteristic of the CIT opening area according to the engine rotation speed in the control device for a construction machine according to one embodiment of the present invention.

FIG. 10 is a diagram showing a relationship between a required flow rate of negative flow control and a negative control pressure in the control device for a construction machine according to one embodiment of the present invention.

FIG. 11 is a diagram showing the relationship between the allowable flow rate of the negative flow control and the pump discharge pressure in the control device for a construction machine according to one embodiment of the present invention.

FIG. 12 is a flowchart for explaining the tilt angle control by the basic tilt angle control amount setting means of the control device for the construction machine according to one embodiment of the present invention. It is.

FIG. 13 is a flowchart for explaining the tilt angle correction control by the tilt angle control amount correction means of the control device for a construction machine according to one embodiment of the present invention.

FIG. 14 is a diagram showing a relationship between an engine rotation speed and a C-T opening area in the control device for a construction machine according to one embodiment of the present invention.

FIG. 15 is a diagram illustrating a relationship between an engine rotation speed and a back pressure in the control device for a construction machine according to one embodiment of the present invention.

FIG. 16 is a schematic perspective view showing a conventional construction machine.

FIG. 17 is a diagram showing the relationship between the engine rotation speed and the C-T opening area in a conventional construction machine control device.

FIG. 18 is a diagram showing the relationship between the engine rotation speed and the back pressure in a conventional construction machine control device. BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

First, a construction machine according to the present embodiment will be described.

This construction machine is a construction machine (working machine) such as a hydraulic shovel, as described in the related art (see FIG. 16), and includes an upper revolving unit 102, a lower traveling unit 100, and a working device. Consists of 1 1 8

The undercarriage 100 has a right track 100R and a left track 100L that can be driven independently of each other, while the upper revolving structure 102 has a lower track 100 On the other hand, it is provided so as to be pivotable in a horizontal plane. The working device 118 mainly includes a boom 103, a stick 104, a socket 108, and the like. The boom 103 rotates with respect to the upper rotating body 102. It is pivoted as much as possible. Also, at the end of the boom 103, A stick 104 is rotatably connected in the vertical plane.

A boom drive hydraulic cylinder (boom cylinder, hydraulic actuator) 105 for driving the boom 103 is provided between the upper rotating body 102 and the boom 103. In addition, between the boom 103 and the stick 104, a stick driving hydraulic cylinder (stick cylinder, hydraulic actuator) 106 for driving the stick 104 is provided. I have. Also, between the stick 104 and the bucket 108, a bucket driving hydraulic cylinder (bucket cylinder, hydraulic actuator) 107 for driving the bucket 108 is provided. .

With such a configuration, the boom 103 is in the directions a and b in the figure, the stick 104 is in the directions c and d in the figure, and the baggage 108 is the direction e and f in the figure. It is configured to be rotatable in the direction.

Here, FIG. 2 is a diagram schematically showing a main part of a hydraulic circuit of such a hydraulic shovel.

As shown in FIG. 2, the left track 100 L and the right track 100

R is provided with a driving motor 109 L and 109 R as independent power sources, and the upper revolving unit 102 is provided with an upper revolving unit with respect to the lower traveling unit 100. A turning motor 110 for turning the 102 is turned is provided.

These traveling motors 110 L and 109 R and turning motors 110 are configured as hydraulic motors that are operated by hydraulic pressure. As described later, engines (mainly diesel engines) are used. Hydraulic oil from a plurality (here, two) of hydraulic pumps 51, 52 driven by 50 is supplied at a predetermined pressure via a hydraulic circuit 53, and the operation supplied in this manner is performed. Each hydraulic motor 109L, 109R, 110 is driven according to the hydraulic pressure. Here, the hydraulic pumps 51 and 52 discharge the hydraulic oil in the reservoir tank 70 as a predetermined oil pressure. Here, a swash plate rotary piston pump (piston type variable displacement pump, variable discharge amount type piston) is used. Pump). These hydraulic pumps 51 and 52 can adjust the pump discharge flow rate by changing the stroke amount of a piston (not shown) provided in the hydraulic pump.

That is, in these hydraulic pumps 51 and 52, one end of the piston is configured to abut on a swash plate (cleave plate: not shown), and the inclination (tilt angle) of the swash plate will be described later. By changing the stroke based on the operation signal from controller 1, the stroke of the piston can be changed and the pump discharge flow can be adjusted.

As described above, the inclination of the swash plate can be changed based on the operation signal from the controller 1. In addition to the pressure of the hydraulic oil in the oil passages constituting the hydraulic circuit, each operation member 5 by the operator is changed. Because the amount of operation in 4 can also be taken into account, the operating feeling during operation can be improved compared to the conventional method in which the pressure of the hydraulic oil in the oil passage is guided to change the inclination of the swash plate. Can be done.

In addition, the engine 50 allows the operator to set the engine speed by switching the engine speed setting dial. Here, the maximum engine speed (for example, about 200 rpm) and the minimum engine speed are set. It can be switched in multiple stages between the engine rotation speed (for example, about 1000 rpm). Note that the engine speed is not limited to such a stepwise switching, but may be a type that can be changed smoothly. The total horsepower of the engine 50 is consumed for driving these hydraulic pumps 51 and 52 and a later-described pilot pump 83.

In addition, for each cylinder 105 to 107, As in the case of 09 L, 109 R and turning motor 110, the hydraulic oil supplied from multiple (here, two) hydraulic pumps 51, 52 driven by engine 50 It is designed to be driven by hydraulic pressure.

The operation room 101 has a left lever, a right lever, a left pedal, and a left lever for controlling the operation of the hydraulic excavator (running, turning, boom turning, stick turning, and baguette turning). A plurality of operating members 54 such as a right pedal are provided. These operation members 54 are configured as electric operation members (for example, electric operation levers), and output an electric signal corresponding to the operation amount to a controller (control means) 1 described later.

Then, for example, when the operator operates these operating members 54, the control valves 57 to 60 and 62 to 65 interposed in the hydraulic circuit 53 are controlled, and each cylinder 1 05 to 107 and hydraulic motors 109 L, 109 R, 110 are driven. As a result, the upper swing body 102 can be turned, the boom 103, the stick 104, the bucket 108, and the like can be turned, and the hydraulic shovel can be run.

Next, a hydraulic circuit 53 for controlling these cylinders and the like will be described.

As shown in FIG. 2, the hydraulic circuit 53 includes a first circuit unit 55 and a second circuit unit 56.

Among them, the first circuit section 55 is an oil passage connected to the first hydraulic pump 51.

Control of the control valve 57 for the right running motor, the control valve 58 for the packet, the control valve 59 for the first boom, the control valve 60 for the second stick, etc. And a valve.

Then, the hydraulic oil from the first hydraulic pump 51 is supplied to the right traveling motor 110 R via the oil passage 61, the right traveling motor evening control valve 57, and the right traveling motor 110 R is driven. Also, the first hydraulic pump 5 1 These hydraulic oils are supplied to the packet driving hydraulic cylinder 107 via the oil passage 61 and the baguette control valve 58, and the oil passage 61 and the first boom control valve 59 To the boom drive hydraulic cylinder 105 through the oil passage 61 and the second stick control valve 60 to the stick drive hydraulic cylinder 106. Each cylinder 105, 106, 107 is driven.

A throttle (throttle with a relief valve) 81 is provided downstream of the oil passage 61 of the first circuit portion 55, and hydraulic fluid from the first hydraulic pump 51 is supplied to the reservoir through the throttle 81. It returns to tank 70.

The second circuit portion 56 includes an oil passage 66 connected to the second hydraulic pump 52, a left traveling motor control valve 62 interposed in the oil passage 66, and a turning motor evening control valve 6. 3, a control valve such as a first stick control valve 64, a second boom control valve 65, etc., and a throttle 82.

Then, the hydraulic oil from the second hydraulic pump 52 is supplied to the left traveling motor 109 L via the oil passage 66 and the left traveling motor control valve 62, whereby the left traveling motor 90 109 L is driven. Hydraulic oil from the second hydraulic pump 52 is supplied to the turning motor 110 via the oil passage 66 and the turning motor control valve 63, whereby the turning motor 110 Are driven. Further, the hydraulic oil from the second hydraulic pump 52 is supplied to the hydraulic cylinder 106 for driving the stick via the oil passage 66 and the control valve 64 for the first stick. , Is supplied to the boom driving hydraulic cylinder 105 via the second boom control valve 65, whereby the respective cylinders 105, 106 are driven.

A throttle (a throttle with a relief valve) 82 is provided on the downstream side of the oil passage 66 of the second circuit portion 56, and the hydraulic oil from the second hydraulic pump 52 is provided through the throttle 82. It returns to the reservoir tank 70. The control valves 57 to 60 and 62 to 65 are housed in a control unit (not shown).

As described above, in the present embodiment, the second stick is set so that a sufficient hydraulic oil is supplied to the important stick 104 in the operation of the construction machine even at the same time when the other work machine 118 is operated simultaneously. In addition to the hydraulic oil from the second hydraulic pump 52 in the circuit section 56, the hydraulic oil from the first hydraulic pump 51 in the first circuit section 55 is also supplied to the stick driving hydraulic cylinder 106. It has become.

For this reason, the first stick control valve 64 is interposed in the oil passage 66 of the second circuit portion 56, and the second stick control valve 60 is interposed in the oil passage 61 of the first circuit portion 55. Is equipped. Then, the first stick control valve 64 is controlled by the proportional control valves 64 a and 64 b, and the second stick control valve 60 is controlled by the proportional control valves 60 a and 60 b. As a result, hydraulic oil can be supplied to and discharged from the hydraulic cylinder 106 for driving the stick.Similarly, sufficient operation for the boom In order to supply hydraulic oil, in addition to the hydraulic oil from the first hydraulic pump 51 in the first circuit section 55, the hydraulic oil from the second hydraulic pump 52 in the second circuit section 56 is also boom driven. _t Therefore, adapted to be supplied to use the hydraulic cylinder 1 0 5, the first boom control valve 5 9 is via instrumentation to the oil passage 61 of the first circuit portion 5 5, the second circuit section 5 6 The second boom control valve 65 is interposed in the oil passage 66 of the second boom. The first boom control valve 59 is controlled by the proportional control valves 59a and 59b, and the second boom control valve 65 is controlled by the proportional control valves 65a and 65b. The hydraulic oil can be supplied to and discharged from the boom drive hydraulic cylinder 105.

In this embodiment, a stick regeneration valve 76 is interposed in the oil passages 67, 68 for supplying and discharging hydraulic oil to and from the hydraulic cylinder 106 for driving the stick. A predetermined amount of hydraulic oil from the side oil passage to the hydraulic oil supply side oil passage Can be played.

Similarly, boom regeneration valves 77 are also interposed in the oil passages 78, 799 that supply and discharge hydraulic oil to the boom drive hydraulic cylinder 105, and operate from the hydraulic oil discharge side oil passage. A predetermined amount of hydraulic oil can be regenerated to the oil supply side oil passage.

Here, each of the control valves 57 to 60 and 62 to 65 is configured as a spool valve as shown in Fig. 3, and each is configured with a plurality of (here, five) throttles. .

That is, as shown in FIG. 3, the control valves 57 to 60 and 62 to 65 are connected to the first hydraulic pump 51, the second hydraulic pump 52, and the stick driving hydraulic cylinder 106, respectively. (Hydraulic oil supply passage, P-C passage) 6 1a, P-C restrictor 8 interposed in 66a, stick drive hydraulic cylinder 106 and reservoir tank 70 Oil passage (hydraulic oil discharge passage, C-T passage) 66 C, T throttle 9 interposed in 69 b, 69, 1st hydraulic pump 51, 2nd hydraulic pump 52 It is configured to include a bypass passage restrictor 10 interposed in oil passages (bypass passages) 61b and 66c communicating with the reservoir tank 70.

In FIG. 3, the stick control valves 60 and 64 are in the stick lowered position, but the stick control valves 60 and 64 are moved upward in FIG. By interposing the bypass passage restrictors 10 of 60 and 64 in the bypass passages 6 1b and 66c, the stick control valves 60 and 64 can be set to the neutral position. By moving the control valves 60 and 64 upward in Fig. 3, the P-C throttle 8 of the stick control valves 60 and 64 passes through the P-C passages 61a and 66a. At the same time, the C-T throttle 9 of the stick control valves 60 and 64 is interposed in the C-T passages 66 b and 69 to control the stick control valves 60 and 64. Stay Can be in the raised position.

Here, in the present embodiment, the pump flow rate becomes maximum at the maximum engine rotation speed, and even when the operating member is fully operated, the pump is not excessively throttled by the C-T throttle 9 and is adjusted according to the maximum pump flow rate. The diameter of the C-T throttle 9 is set to be sufficiently larger than that of the conventional one so that the hydraulic oil with the adjusted flow rate can be smoothly and surely discharged through the C_T passages 66b and 69. You.

In other words, the C-T opening area depends on the flow rate of the hydraulic oil supplied through the P-C passages 6 la and 66 a when the operation amount of the operation member 54 is the maximum and the engine rotation speed is the maximum. It is set so that the hydraulic fluid with the reduced flow rate is discharged through the C-T passages 66b and 69.

When setting the CT opening area, since there is a difference in cross-sectional area between the head-side oil chamber and the rod-side oil chamber of the hydraulic cylinder 106 for stick drive, The cross-sectional area ratio is taken into account. In other words, the flow rate of hydraulic oil supplied from the P_C passages 61 a and 66 a into the head-side oil chamber of the hydraulic cylinder 106 for stick drive, and the rod of hydraulic cylinder 106 for stick drive The ratio of the flow rate of the hydraulic oil discharged from the side oil chamber to the C-T passages 66 b and 69 depends on the cross-sectional area of the head side oil chamber of the hydraulic cylinder 106 for stick drive and the lock. It is obtained by taking into account the ratio to the cross-sectional area of the oil chamber on the pressure side, and the CT opening area, that is, the diameter of the CT throttle 9, is set accordingly.

The cross-sectional area (ie, volume) of each oil chamber is different, and the volume of hydraulic oil in the oil chamber on the rod side is smaller than the volume of hydraulic oil in the oil chamber on the head side. When hydraulic oil is supplied from 1a and 66a to the head-side oil chamber and the piston that constitutes the stick drive hydraulic cylinder 106 moves, the CT passage from the rod-side oil chamber moves. The flow rate of the hydraulic oil discharged to 66 b and 69 is the hydraulic oil supplied to the head-side oil chamber from the P-C passage 6 la and 66 a. However, the flow rate of supplied hydraulic oil and the flow rate of discharged hydraulic oil are almost the same under the same pressure.

Since there is a difference in cross-sectional area between the head-side oil chamber and the mouth-side oil chamber of the hydraulic cylinder 106 for driving the stick, the hydraulic oil with a flow rate corresponding to the ratio of the cross-sectional area of these oil chambers From the hydraulic chamber on the rod side of the hydraulic cylinder 106 for driving the stick. —The force that will be discharged to the passages 6 6 13 and 6 9 Hydraulic factor that has no cross-sectional area difference between the hydraulic oil supply side and hydraulic oil discharge side of the hydraulic actuator In the evening, approximately the same amount of hydraulic oil as the flow rate of the hydraulic oil supplied through the P-C passages 61a and 66a is discharged from the C-T passages 66b and 69. Become.

When setting the diameters of the apertures 8, 9, and 10, each operating member is fully operated to ensure the interlocking of the working devices 118 such as the boom 103 and the stick 104. In this case, all working devices 1 18 are taken into account.

The opening area of the oil passages 6 1 a and 66 a communicating the first hydraulic pump 51 and the second hydraulic pump 52 and the hydraulic cylinder 106 for driving the stick is controlled by the PC throttle 8. The oil supply passage opening area and PC opening area are adjusted.

The opening area of the oil passages 66 b and 69 communicating the stick drive hydraulic cylinder 106 and the reservoir tank 70 with the C_T throttle 9 (opening area of the hydraulic oil discharge passage, C-T Opening area) is adjusted.

The opening area of the oil passages 6 1 b and 66 c communicating the first hydraulic pump 51 and the second hydraulic pump 52 and the reservoir tank 70 by the bypass passage throttle 10 (opening area of the bypass passage) ) Is adjusted.

By the way, in this embodiment, as shown in FIG. 2, each of the control valves 57 to 60,

Pilot pump 83 to control 6 2 to 65 and proportional pressure reducing valve 5 A pilot hydraulic circuit including 7a to 60a, 57b to 60b, 62a to 65a, and 62b to 65b is provided. In Fig. 2, the pilot pump 83 and the proportional pressure reducing valves 57a to 60a, 57b to 60b, 62a to 65a, 62b are provided in the pilot port hydraulic circuit. Only ~ 65b is shown, and the pilot oil pressure is indicated by the symbol P, omitting the pilot oil passage.

Here, the proportional pressure reducing valves 57 a to 60 a, 57 b to 60 b, 62 a to 65 a, 62 b to 65 b are solenoid valves, and are operated by the controller 1 described later. It is activated by a signal. Thus, the pilot oil pressure from the pilot pump 83 is applied to each of the control valves 57 to 60 and 62 to 65 as a predetermined pressure based on the operation signal from the controller 1.

With such a configuration, for example, in order to operate the stick 104, the operating member 54 in the operation room 101 is operated, and the pipe hydraulic pressure P from the pilot pump 83 is applied to the pipe By acting on the stick control valves 60 and 64 through the oil passage, the stick control valves 60 and 64 are driven to the required positions. As a result, the supply and discharge of the hydraulic oil for the stick driving hydraulic cylinder 106 is adjusted, and these cylinders 105, 106 are driven to expand and contract to the required length, whereby the stick 104 is operated. .

For example, to rotate the stick 104 inward (stick-in), the stick driving hydraulic cylinder 106 may be extended. In this case, the pilot oil pressure is made to act on the second stick control valve 60 through the pilot oil passage. As a result, the spool position of the second stick control valve 60 becomes the stick inner rotation position (stick position), and the hydraulic oil from the first hydraulic pump 51 of the first circuit portion 55 Is supplied to one chamber of the stick driving hydraulic cylinder 106 through the oil passages 61 and 67. this On the other hand, the hydraulic oil in the other chamber of the stick driving hydraulic cylinder 106 is discharged to the reservoir tank 70 via the oil passages 68 and 69. As a result, the stick driving hydraulic cylinder 106 is extended, and the stick 104 is rotated inward as shown by the arrow d in FIG.

Conversely, to rotate the stick 104 outward (stick-out), the stick driving hydraulic cylinder 106 may be contracted. In this case, the pilot oil pressure is applied to the second stick control valve 60 through the pilot oil passage. As a result, the spool position of the second stick control valve 60 becomes the stick outside rotation position (stick out position), and the hydraulic oil from the first hydraulic pump 51 of the first circuit portion 55 flows through the oil passage. It is supplied to the other chamber of the stick driving hydraulic cylinder 106 via 61 and 68. On the other hand, the hydraulic oil in one chamber of the stick driving hydraulic cylinder 106 is discharged to the reservoir tank 70 through the oil passages 67 and 69. As a result, the stick driving hydraulic cylinder 106 is contracted, and the stick 104 is rotated outward as shown by the arrow c in FIG.

Further, in order to maintain the current state of the stick driving hydraulic cylinder 106, the pilot hydraulic pressure is applied to the second stick control valve 60 as appropriate, and the second stick control valve 60 is operated. The position of each spool may be set to the neutral position (the hydraulic supply / discharge path shutoff position). As a result, the supply and discharge of the hydraulic oil in each oil chamber of the stick driving hydraulic cylinder 106 is stopped, and the stick 104 is held at the current position.

By the way, various sensors are attached to the construction machine configured as described above, and a detection signal from each sensor is sent to a controller 1 described later.

For example, an engine 50 for driving the hydraulic pumps 51 and 52 is provided with an engine speed sensor 71. The detection signal from the sensor 71 is sent to the controller 1 described later. The controller 1 performs feedback control so that the actual engine speed becomes the target engine speed set by the engine speed setting dial during the operation.

Also, the first hydraulic pump 51 of the first circuit section 55 and the first hydraulic pump 51 of the second circuit section 56

(2) On the discharge side of the hydraulic pump 52, a pressure sensor (PZS-P1) 72 and a pressure sensor (PZS-P2) 73 are provided to detect the pump discharge pressure. Detection signals from the sensors 72 and 73 are sent to a controller 1 described later.

In addition, pressure valves are provided downstream of the control valves 57 to 60 of the oil passage 61 of the first circuit unit 55 and the control valves 62 to 65 of the oil passage 66 of the second circuit unit 56, respectively. The sensor (PZS-N1) 74 and the pressure sensor (PZS-N2) 75 are provided, and the detection signals from these pressure sensors 74 and 75 are sent to the controller 1 described later. It has become.

Further, a pressure sensor (PZS-BMd) 80 is provided in an oil passage for supplying and discharging hydraulic oil to and from the boom drive hydraulic cylinder 105. The boom drive hydraulic cylinder 100 is provided by the pressure sensor 80. The rod side pressure (load pressure) of 5 can be detected. The detection signal from the pressure sensor 80 is sent to a controller 1 described later.

In the present embodiment, a controller 1 is provided to control the construction machine configured as described above.

The controller 1 controls the first hydraulic pump 51, the second hydraulic pump 52, and the regeneration valve 76 based on the detection signals from the sensors 71 to 75 and 80 and the electric signal from the operation member 54. , 7 7, By outputting operation signals to the control valves 57 to 60, 62 to 65, the first hydraulic pump 51 and the second hydraulic The tilt angle control of the pump 52, the position control of the control valves 57 to 60 and 62 to 65, and the position control of the regeneration valves 76 and 77 are performed.

Of these, the tilt angle control of the first hydraulic pump 51 and the second hydraulic pump 52 by the controller 1 is performed on the downstream side of the bypass passage 61 b of the first circuit section 55 and the second circuit section 56. Negative flow control is performed based on detection signals from the respective pressure sensors 74 and 75 provided downstream of the bypass passage 66c. Since the negative flow control is performed based on the pressures detected by the pressure sensors 74 and 75, the pressure detected by the pressure sensors 74 and 75 is also referred to as a negative control pressure.

Here, the negative flow control (electronic negative flow control system) is a pump flow control with a negative characteristic that reduces the pump discharge flow rate when the pressure downstream of the bypass passages 61b and 66c increases. Say.

Here, the negative flow control is based on the operation amount of the operation member 54, that is, the flow control in which the pump discharge flow rate is controlled according to the negative control pressure, and the load pressure applied to the actuator, that is, the pump discharge pressure. It is divided into horsepower control where the pump discharge flow rate is controlled.

Among them, the flow control can control the speed of the actuator (each cylinder) within the allowable horsepower. In other words, the pump discharge flow rate can be controlled in accordance with the operation amount of the operation member 54, that is, the negative control pressure, whereby the speed of the actuator can be controlled.

By the way, when the operation member 54 is fully operated and the pump discharge flow rate is maximized and the speed of the actuator is maximized, the pump discharge flow rate (that is, the speed of the actuator) is determined by the following equation. Is done.

Pump discharge flow Q = Allowable horsepower WZ Pump discharge pressure P In this state, if the load pressure applied to the actuator changes, the pump discharge pressure P also changes, and the pump discharge flow rate Q also changes according to the above equation, so that the speed of the actuator changes as well. Will be. As described above, the pump discharge flow rate Q is not controlled according to the operation amount of the operation member 54, but is controlled according to the load pressure applied to the actuator, that is, the pump discharge pressure P. The control in a state where the magnitude of the flow rate Q depends on the allowable horsepower W of the engine 50 that drives the first hydraulic pump 51 and the second hydraulic pump 52 is called horsepower control.

When such horsepower control is performed, even if the operator fully operates the operating member 54 and requests the maximum speed of the actuator, the actual speed of the actuator is determined by the magnitude of the load pressure. It will be. In this case, the horsepower of the engine 50 becomes the maximum allowable value.

Also, for example, in the case of operating a plurality of actuators simultaneously, even if each operating member 54 is not fully operated, hydraulic oil is supplied to each actuator and the negative control pressure is reduced. If the required flow rate falls below the allowable flow rate determined by the allowable horsepower, the pump tilt angle control is performed so that the required flow rate in the horsepower control is achieved.

By the way, when the operation member 54 is in the neutral position, that is, when the operator does not operate the operation member 54, the work machine 118 does not work at all, and each actuator (cylinder, etc.) is operated. Since there is no need to drive the pump, the pump discharge flow rate from the hydraulic pumps 51 and 52 is desirably set to zero.

For this reason, in the present embodiment, each of the control valves 57 to 60 and 62 to 65 is arranged so that the bypass passages 6 lb and 66 c are open at the spool neutral position. That is, when the operating member 54 is in the neutral position, the hydraulic oil supplied from the hydraulic pumps 51 and 52 returns to the reservoir tank 70 through the bypass passages 61b and 66c. I have. As a result, when the operation member 54 is in the neutral position, the pressure immediately upstream of the throttles 81, 82 provided downstream of the bypass passages 61b, 66c increases, and the negative flow control is performed. Thus, the pump discharge flow rate from the variable displacement hydraulic pumps 51 and 52 is controlled to decrease.

On the other hand, when the operation member 54 is operated, an amount of hydraulic oil corresponding to the operation amount is supplied to each actuator (cylinder and the like), and the remaining hydraulic oil is supplied to the bypass passages 6 1 b and 66 c. Through the reservoir tank 70.

As described above, the throttle (orifice) 8 1 is located downstream of the bypass passages 6 lb and 66 c for returning the hydraulic oil not supplied to the hydraulic actuator through the respective control valves to the reservoir tank 70. , 82 are provided. Pressure sensors 74 and 75 are interposed in the bypass passages 6 1 b and 66 c immediately upstream of the throttles 8 1 and 82, and the throttles detected by the pressure sensors 74 and 75 are provided. The tilt angles of the hydraulic pumps 51 and 52 are controlled based on the pressures immediately upstream of the pumps 81 and 82.

When the operator operates the operation member 54, the control valves 57 to 60 and 62 to 65 move according to the operation amount of the operation member 54, and the bypass passages 61b and 66c are moved. And the flow rate of hydraulic oil flowing through the bypass passages 6 1 b and 66 c decreases, but the diameter of the throttles 8 1 and 8 2 is constant, so the throttles 8 1 and 8 are reduced by the reduced flow rate. The pressure immediately upstream of 2, that is, the pressure detected by the pressure sensors 74 and 75 decreases, and the variable displacement hydraulic pumps 51 and 52 increase the pump discharge flow rate in accordance with the reduced pressure. The tilt angle control is performed.

This means that the pump discharge flow rate is controlled to increase according to the operator's request, that is, the operation amount of the operation member 54 by the operator, This means that by operating the operating member 54, the operator can control the pump discharge flow rate from the hydraulic pumps 51 and 52 to control the speed of each actuator (each cylinder and the like).

By the way, in the present embodiment, as the position control of the control valves 57 to 60 and 62 to 65 by the controller 1, the control valves 57 to 60 and 60 according to the operation of the operation member 54 by the operator are used. In addition to the position control of 62 to 65, the position control of each control valve 57 to 60 and 62 to 65 according to the engine speed is also performed.

That is, the controller 1 is a proportional pressure reducing valve (a pilot pressure) that adjusts the pilot oil pressure applied to each of the control valves 57 to 60 and 62 to 65 based on the electric signal from the operation member 54. Control valve) 57a to 60a, 57b to 60b, 62a to 65a, 62b to 65b I have.

Further, the controller 1 controls each of the control valves 57 to 7 based on a detection signal from an engine speed sensor 71 attached to an engine 50 that drives the first hydraulic pump 51 and the second hydraulic pump 52. Proportional pressure reducing valve (pilot pressure control valve) for adjusting pilot oil pressure acting on 60, 62 to 65 57 a to 60 a, 57 b to 60 b, 62 a to 65 An operation signal is output to control the operation of a, 62b to 65b.

Then, based on such an operation signal, the proportional pressure reducing valves 57a to 60a,

57 b to 60 b, 62 a to 65 a, 62 b to 65 b are operated, and by this, the pressure of the pilot hydraulic pressure supplied from the pilot pump 83 is adjusted, and The spool stroke amount (spool movement amount) of the control valves 57 to 60 and 62 to 65 is adjusted.

The control device for a construction machine according to the present embodiment is configured as described above, and various controls are performed by the controller 1. In order to lower the weight of the stick in the direction in which gravity acts, the self-weight lowering control of the stick 104 is performed.

Next, the self-weight drop control of the stick, which is a feature of the control device and the control method of the construction machine according to the present embodiment, will be described.

Here, FIG. 1 is a control block diagram for explaining the self-weight drop control of the stick by the control device of the construction machine according to the present embodiment.

In this embodiment, as shown in FIG. 1, the controller 1 includes a proportional pressure reducing valve control means 2 and a pump tilt angle control means 3 in order to perform the self-weight drop control of the stick 104. Have been.

The proportional pressure reducing valve control means 2 includes a basic control amount setting means 4 and a correction means 5 among them.

The basic control amount setting means 4 calculates a basic control amount of the proportional pressure reducing valves 60a, 60b, 64a, 64b based on an electric signal corresponding to the operation amount from the operation member 54. This basic control amount is output to the correction means 5.

Here, the basic control amount relates the operation amount of the operating member 54 as shown in FIG. 4 to the basic control signals of the proportional pressure reducing valves 60a, 60b, 64a, and 64b. Required by map.

In this map, the operation amount of the operation member 54 is set so that the larger the operation amount of the operation member 54, the larger the movement amount of the proportional pressure reducing valves 60a, 60b, 64a, and 64b. The basic control signal is set to increase as the number increases. Note that in FIG. 4, the basic control signal is constant above the predetermined operation amount because the movement of the proportional pressure reducing valves 60a, 60b, 64a, and 64b at the predetermined operation amount is the maximum. Indicates that

The correction means 5 calculates the control signal rates (correction coefficients) of the proportional pressure reducing valves 60 a, 60 b, 64 a, and 64 b based on the detection signal from the engine speed sensor 71. The signal rate is calculated based on the basic control amount By multiplying this control amount, the basic control amount of the proportional pressure reducing valves 60a, 60b, 64a, and 64b is corrected to calculate a correction control amount. a, 60, 64a, 64b.

Here, the control signal rate is obtained from a map as shown in FIG. 5, which associates the engine speed with the control signal rate of the proportional pressure reducing valve.

In this map, the control signal rate is calculated so that the control signal rate of the proportional pressure reducing valves 60a, 60b, 64a, 64b decreases as the engine speed detected by the engine speed sensor 71 decreases. It is set as shown by NZNmax. In other words, the control signal rate is set so that the stroke amount of the spool constituting the first stick control valve 60 and the second stick control valve 64 decreases as the engine rotation speed decreases. When the engine speed is the maximum, the control signal rate of the proportional pressure reducing valves 60a, 60b, 64a, 64b becomes 1.0 (= NmaxZNmax), and the engine speed becomes the minimum. In this case, the control signal rates of the proportional pressure reducing valves 60a, 60b, 64a, 64b become Nmin / Nmax.

The correction means 5 outputs a control signal corresponding to the correction control amount to the proportional pressure reducing valves 60a, 60b, 64a, 64b.

As a result, the proportional pressure reducing valves 60a, 60b, 64a, 64b are operated in accordance with the control amount calculated by the proportional pressure reducing valve control means 2, and the pilot oil pressure from the pilot pump 83 is proportionally reduced. The pressure is reduced to a predetermined pressure by the valves 60 a, 60 b, 64 a, 64 b and acts on the first stick control valve 60 and the second stick control valve 64, and the first stick control valve 60 The spool constituting the second stick control valve 64 moves.

Here, FIG. 6 is a map in which the correction control signal is related to the stroke amounts of the first stick control valve 60 and the second stick control valve 64. As shown in FIG. 6, the spools constituting the first stick control valve 60 and the second stick control valve 64 increase as the correction control signal (basic control signal X control signal rate) increases. It is controlled so as to be the stroke amount.

In this way, the spools constituting the first stick control valve 60 and the second stick control valve 64 move, and as a result, as shown in FIG. The opening area of the oil passage (PC opening area) that connects the first hydraulic pump 51 or the second hydraulic pump 52 to the stick driving hydraulic cylinder 106, the stick driving hydraulic cylinder 10 6 The opening area of the oil passage that connects the reservoir and the reservoir 70 (C—T opening area), the oil passage that connects the first hydraulic pump 51 or the second hydraulic pump 52 to the reservoir 70 The opening area (bypass passage opening area) changes accordingly.

By the way, in the negative flow control according to the present embodiment, the negative control pressure changes according to the bypass passage opening area which is adjusted according to the operation amount of the operation member 54, and the hydraulic pumps 51 and 52 change according to the changed negative control pressure. The tilt angle control of 52 is performed, and the pump flow rate is controlled.

For this reason, when performing the self-weight descent control of the stick 104, as shown in Fig. 8, the control characteristics of the C-T opening area when the operating member 54 is fully operated may differ depending on the engine rotation speed. Based on the control characteristics set in (1), the CT opening area is controlled in accordance with the operation amount of the operation member 54. In Fig. 8, the control characteristics of the CT opening area at the maximum engine speed are indicated by solid line A, and the control characteristics of the CT opening area at the minimum engine speed are indicated by solid line B. Is shown. Also, in FIG. 8, a broken line C indicates a conventional control characteristic of the CT opening area.

The setting of the engine speed is not limited to the maximum and minimum, but can be set arbitrarily. If possible, the control characteristics of the C-T opening area when the operation member 54 is fully operated may be set according to the engine speed.

As shown in FIG. 8, in the present embodiment, the C-T opening area is controlled in proportion to the operation amount of the operation member 54 and the engine rotation speed, but when the operation amount of the operation member 54 is the maximum ( In the case of full operation), the C-T opening area when the engine speed is the minimum is larger than the C-T opening area when the engine speed is the maximum, regardless of the operation of the operating members 54 by the operator. The spool stroke amount (spool movement amount) constituting the first stick control valve 60 and the second stick control valve 64 is controlled so as to be small.

In other words, in the present embodiment, when the operating member 54 is fully operated when the engine rotation speed is the maximum (when the pump flow rate is the maximum), the control characteristic indicated by the solid line A in FIG. The amount of spool stroke constituting the control valve 60 for the first stick and the control valve 64 for the second stick is set so that the area is maximized. Pressure is not generated to improve work efficiency.

Specifically, at the maximum engine speed N max, the operating member 54 is fully operated by the operator to make the spool the maximum stroke S max, and the maximum pump flow rate as the maximum PC opening area is set to the hydraulic cylinder for stick drive. When the stick 104 is to be lowered by its own weight while maintaining the maximum descent speed of the stick drive hydraulic cylinder 106, the spool stroke is reduced and the spool position is adjusted. Is controlled so as to return from the most moved position to the neutral position side in accordance with the operation amount of the operation member 54 during the operation.

Here, the control is performed such that the spool stroke amount is reduced and the spool position is returned to the neutral position side when the engine rotation speed is the maximum. However, the return amount of the spool to the neutral position is set to zero, the spool position is not controlled to return the spool position to the neutral position, and the spool stroke amount is It may be kept controlled according to the operation amount.

In this case, since the spool has the maximum stroke S max, the C-T opening area is the maximum, but the maximum C-T opening area A max is reduced by the C-T aperture 9, so that the stick drive Excessive hydraulic oil is prevented from being discharged from the hydraulic oil discharge side of the hydraulic cylinder 106, thereby preventing the occurrence of cavitation on the hydraulic oil supply side of the stick driving hydraulic cylinder 106. Has become.

In order to prevent the occurrence of cavitation, the hydraulic oil supply side pressure in the stake driving hydraulic cylinder 106 should be a positive pressure (pressure in the direction of its own weight descent) and a predetermined pressure (for example, it is necessary to ensure the order of about 5 kgf / cm ^2).

As described above, the spool stroke amount is set so that the CT opening area is maximized when the engine speed is the maximum, when the engine speed is the minimum (when the pump flow rate is Set the spool stroke amount so that the C-T opening area is maximized at the minimum, and the cavitation is applied to the hydraulic oil supply side to each cylinder (that is, the oil passage between the pump and each cylinder). When the diameter of the C-T throttle 9 is set so that the cylinder descends at a speed that does not cause the occurrence of excessive throttling, when the engine speed is high (when the pump flow rate increases) due to the C-T throttle 9, This is because work efficiency is reduced.

On the other hand, when the operating speed of the operating member 54 is fully operated by the operator when the engine speed is low (when the pump flow rate is reduced), the CT opening area is maximized by the control characteristic indicated by the solid line B in FIG. As spool stroke By setting the amount, the spools constituting the first stick control valve 60 and the second stick control valve 64 are controlled so as to return to the neutral direction. When the engine speed is low, the CT opening area is reduced compared to when the engine speed is high.

That is, at the minimum engine speed (engine idle speed) Nmin, the operator fully operates the operation member 54 to obtain the maximum descent speed of the hydraulic cylinder 106 for stick drive. When attempting to lower the stick 104 under its own weight, set the spool stroke amount based on the control characteristics as shown by the solid line B in Fig. 8 regardless of the operation amount of the operation member 54 during operation. Control to return the spool to the neutral direction, and to the minimum engine speed N min (minimum pump flow) to prevent cavitation on the hydraulic oil supply side of the stick drive hydraulic cylinder 106. Corresponding minimum C—T opening area A min. Here, let S min be the amount of the spark outlet opening when the minimum C-T opening area A min is obtained.

As a result, when the engine speed is at the maximum, it is possible to prevent extra horsepower consumption, deterioration of fuel consumption, and deterioration of the cooling performance, and at the same time, when the engine speed is at the minimum. In addition, the occurrence of cavitation can be prevented.

For this reason, the engine rotation speed N and C corresponding to the

— T opening area A, C _ Controller 1 has a data sheet (map) relating spool stroke amount S corresponding to T opening area A. The details will be described later.

As described above, in the present embodiment, the CT opening area is adjusted by changing the stroke amount of the spool constituting the first stick control valve 60 and the second stick control valve 64. , C—T opening area is For example, the engine rotational speed is adjusted to a predetermined rotational speed (approximately 1 0 0 0 rpm) in back pressure Jo Tokoro pressure (approximately 4 0 kgf Z cm ² or so).

By the way, when the operating member 54 is fully operated when the engine speed is the maximum (when the pump flow rate is the maximum), the PC opening area becomes the maximum, but also in this case, the pressure loss should be prevented. The diameter of the P_C aperture 8 for adjusting the P_C opening area is set to be sufficiently large.

As described above, since the PC opening area is set sufficiently large with respect to the pump flow rate, when the engine rotation speed is low (when the pump flow rate decreases), the first stick control is performed as described above. The spool constituting the valve 60 and the second stick control valve 64 is controlled so as to return to the neutral direction in accordance with the engine speed, and even if the PC opening area is reduced, the PC throttle is provided. 8 does not cause pressure loss, etc., and does not affect the performance of construction machinery.

In addition, the bypass passage opening area is the largest when the engine speed is the maximum (pump flow rate is the largest) and the operating member 54 is not operated, and the bypass passage opening area is the largest. The diameter of the bypass passage restrictor 10 for adjusting the bypass passage opening area is set so as not to cause the occurrence. However, when the operating member 54 is fully operated when the engine rotation speed is not at the maximum, the first stick control valve 60 and the second stick control valve 6 are used to reduce the C-T opening area. 4 is controlled to return to the neutral direction, the opening area of the bypass passage increases, the negative control pressure increases, and the pump flow rate decreases. Will have an effect.

For this reason, in the present embodiment, as will be described later (see FIG. 13), the tilt angle control amount correcting means 7 tilts the maximum tilt angle control amount instead of the basic tilt angle control amount in the negative flow control. Set as angle control amount It is like that.

The operations of the first stick control valve 60 and the second stick control valve 64 controlled as described above are as follows.

In other words, when the operating member 54 is fully operated by the operator, the spool stroke amount is maximized, the spool is moved most, and the C—T opening area reduced by the C—T aperture 9 is the force that maximizes the aperture. In the present embodiment, when the engine rotation speed is low, the spool at the position where the spool stroke amount is maximized by the full operation of the operation member 54 by the operator and is the most moved is set so that the C-T opening area becomes small. Control is performed so that the spool is returned to the neutral position more (the return amount of the spool is large) On the other hand, when the engine speed is high, the spool at the most moved position is neutral so that the C-T opening area is large. It is controlled to return slightly to the position side (spool return amount is small or zero).

In this manner, in the present embodiment, as shown in FIG. 14, the opening area of the oil passage between the stick driving hydraulic cylinder 106 and the reservoir tank 70 according to the engine rotation speed is determined. (C_T opening area). That is, in the present embodiment, the first stick control valve 60 and the second stick control valve 64 are configured such that the C_T opening area increases as the engine rotation speed increases. The amount of stroke of the spool is controlled. _C By this, for example, control is performed so that the engine speed is at a predetermined rotation speed (about 100 rpm) and the back pressure is at a predetermined pressure (about 40 kgf Z cm ² ). Therefore, even if the engine rotation speed increases and the pump discharge flow rate increases, a resistance loss occurs due to the CT throttle 9 and acts on the hydraulic cylinder 106 for the stick drive as in the conventional technology. It is possible to prevent the back pressure from gradually increasing to, for example, a pressure of about 14.5 kgf / cm ² , reduce pressure loss, and improve cooling performance. Wear. In addition, it is possible to prevent the stick 104 from lowering due to the back pressure, thereby preventing the work efficiency from deteriorating.

Further, according to the present embodiment, even if the engine rotation speed increases and the pump discharge flow rate increases, no resistance loss occurs due to the C-T throttle 9, and as shown in FIG. Since the back pressure is constant irrespective of the speed, the predetermined pressure (approximately 40 kgf / cm ² ) required to lower the hydraulic cylinder 106 for stick drive during stick-in operation while utilizing gravity is used. It suffices to act on the hydraulic cylinder 106 for stick drive, and it is not necessary to apply an extra pressure corresponding to the back pressure unlike the prior art, so that power loss can be reduced.

In the present embodiment, the control characteristic of the C-T opening area when the operation amount of the operation member 54 is the maximum is set according to the engine speed. However, the present invention is not limited to this. As shown in FIG. 9, not only when the operation amount of the operation member 54 is the maximum, but also when the control characteristic of the C-T opening area according to the operation amount of the operation member 54 is set for each engine speed. good. Here, the case where the engine speed is maximum and the case where the engine speed is minimum are shown. The case where the engine speed is maximum is indicated by a solid line A, and the case where the engine speed is minimum is indicated by a solid line B.

By the way, the P_C opening area, the C-T opening area, and the bypass passage opening area are all provided in the first stick control valve 64 and the second stick control valve 60 configured as one spool valve. Because it is determined by the P-C throttle 8, the C-T throttle 9, and the bypass passage throttle 10, the first stick is used to adjust the C-T opening area when controlling the self-weight drop of the stick 104. When the control valve 64 or the second stick control valve 60 is moved, the bypass passage opening area is also adjusted, and the bypass flow rate of the hydraulic oil flowing through the bypass passages 6 1 b and 66 c also changes. To be lost Therefore, the pressure of the hydraulic oil downstream of the bypass passage used in the negative flow control will change.

For this reason, in the present embodiment, as will be described later, the pump tilt angle control means

The pump tilt angle control amount is corrected by the tilt angle control amount correction means 7 of 3.

The pump tilt angle control means 3 includes basic tilt angle control amount setting means 6 and tilt angle control amount correction means 7. The basic tilt angle control amount setting means 6 and the tilt angle control amount correction means 7 perform pump tilt angle control as shown in the flowcharts of FIGS. 12 and 13 described later.

Of these, the basic tilt angle control amount setting means 6 determines the basic tilt angle control amount of the first hydraulic pump 51 and the second hydraulic pump 52 based on the detection signals from the pressure sensors 74 and 75. The basic tilt angle control amount is output to the tilt angle control amount correction means 7.

Here, the basic tilt angle control amount is a negative valve control that controls the discharge flow rate from the hydraulic pump based on a characteristic that is substantially inversely proportional to the flow rate of the hydraulic oil in the bypass passages 6 lb and 66 c. It is set, specifically, as follows.

That is, the basic tilt angle control amount setting means 6 sets the bypass passages 6 1 b and 66 c of the first circuit portion 55 and the second circuit portion 56 detected by the pressure sensors 74 and 75. The operating hydraulic pressure (negative control pressure) P _N1 , P _N2 on the downstream side is read, and the negative control pressure P _{N1 is} read from the map as shown in Fig. 10 in which the negative control pressure P _N and the required flow rate Q _N are related. It is adapted to set the required flow rate Q _N1, Q _N2 corresponding to P _N2 (specifically required flow rate Q _N1, the pump tilting angle corresponding to _{_{_{Q N2 V N1, V N2)}}} . The required flow rate is the flow rate required in negative flow control. Also, in Figure 10 (Specifically required flow pump tilting angle V _N1 to equivalent to Q _N1) required flow rate Q _N1 corresponding to the negative control pressure P _N1 are shown only.

On the other hand, the basic tilt angle control amount setting means 6 calculates the pump discharge pressures P _P1 and P _P2 of the first hydraulic pump 51 and the second hydraulic pump 52 detected by the pressure sensors 72 and 73. Loading, from the map shown in the pump discharge pressure P _P and allowable flow Q 1 1 and _P digits relationship Dzu, corresponding to the pump discharge pressure read P _P1, P _P2 allowable flow Q _P1, Q _P2 ( Specifically, the pump tilt angles V _P1 and V _P2 ) corresponding to the allowable flow rates Q _P1 and Q _P2 are set. The allowable flow rate refers to a pump discharge flow rate according to the allowable horsepower of the engine 50 that drives the first hydraulic pump 51 and the second hydraulic pump 52. Further, in FIG. 1 1 shows only allowable flow Q _P1 corresponding to the pump discharge pressure P _P1 (pump tilting angle V _P1 specifically corresponding to allowable flow Q _P1).

The basic tilt angle control amount setting means 6 compares the required flow rate Q _N1, Q _N2 above the allowable flow Q _P1, Q _P2, the smaller the pump flow rate (requested flow Q _N1, Q _N2 or acceptable The pump tilt angles (pump tilt angles V _N1 , V _N2 or pump tilt angles VP ₁ , V _P2 ) are set so that the flow rates Q _P1 and Q _P2 ), and this is used as the first tilt angle control signal. Output is provided to the hydraulic pump 51 and the second hydraulic pump 52.

The basic tilt angle control amount setting means 6 is configured as described above, and operates as shown in the flowchart of FIG.

That is, first, in step S10, the negative control pressures P _N1 and P _N2 are read, and in step S20, the pump discharge pressures P _P1 and P _P2 are read.

Then, to calculate the required flow rate Q _N1, Q _N2 corresponding to step S 3 0 at step S 1 0 negative control pressure P _N1 read in, P _N2 from the map of FIG. 1 0, step S in step 4 0 Calculate the permissible flow rates Q _P1 and Q _P2 corresponding to the pump discharge pressures P _P1 and P _P2 read in 20 from the map in Fig. 11. You.

Then, allowed the required flow rate Q _N1, Q _N2 in Step S 5 0 flow rate Q _P1, Q less whether determined than _P2, the result of this determination, required flow rate Q _N1, Q _N2 is allowable flow Q _P1, If it is determined that the flow rate is smaller than Q _P2 , the process proceeds to step S60, where the required flow rates Q _N1 and Q _N2 are set as the pump flow rates, and the routine returns. Thus, the tilt angles of the first hydraulic pump 51 and the second hydraulic pump 52 are set to be the tilt angles corresponding to the required flow rates Q _N1 and Q _N2 .

On the other hand, if it is determined that the required flow rates Q _N1 and Q _N2 are equal to or higher than the allowable flow rates Q _P1 and Q _P2 , the process proceeds to step S70, where the allowable flow rates Q _P1 and Q _P2 are set as the pump flow rates and the return is performed. I do. Thereby, the tilt angles of the first hydraulic pump 51 and the second hydraulic pump 52 are set to be the tilt angles according to the allowable flow rates Q _P1 and Q _P2 .

When the operation member 54 is fully operated and the engine rotation speed is not at the maximum, the tilt angle control amount correction means 7 sets the basic tilt angle control amount set by the basic tilt angle control amount setting means 6. Instead of the signal, the first hydraulic pump 5 is used as a corrected tilt angle control signal with a maximum tilt angle control signal that maximizes the pump tilt angle of both the first hydraulic pump 51 and the second hydraulic pump 52. 1, and output to the second hydraulic pump 52.

Therefore, the operation amount signal from the operation member 54 and the detection signal from the engine speed sensor 71 are input to the tilt angle control amount correction means 7, and the operation member 54 is fully operated based on these signals. It is determined whether the operating member 54 is fully operated and the engine speed is not the maximum. If the result of this determination is that the operation member 54 is fully operated and the engine speed is not the maximum, the first A maximum tilt angle control signal that maximizes the tilt angle of the hydraulic pumps 51 and 52 is output to the first hydraulic pump 51 and the second hydraulic pump 52 as a tilt angle control signal. It has become. The tilt angle control amount correcting means 7 is configured as described above, and operates as shown in the flowchart of FIG.

That is, first, in step A10, the operation amount signal from the operation member 54 is read, and in step A20, the detection signal from the engine speed sensor 71 is read. Then, in step A30, it is determined whether or not the operating member 54 is fully operated. If the result of this determination is that the operating member 54 is fully operated, the flow proceeds to step A40.

On the other hand, when the operating member 54 is not fully operated, the basic tilt angle control signal set by the basic tilt angle control amount setting means 6 is used as the tilt angle control signal for the first hydraulic pumps 51 and 2. Return to output to hydraulic pump 52.

In step A40, it is determined whether or not the engine rotation speed is the maximum. If it is determined that the engine rotation speed is the maximum, the correction by the tilt angle control amount correction means 7 is not performed. In step 60, the basic tilt angle control signal set by the basic tilt angle control amount setting means 6 is output to the first hydraulic pump 51 and the second hydraulic pump 52 as a tilt angle control signal. . On the other hand, when it is determined that the engine rotation speed is not the maximum, the process proceeds to step A50, and the first hydraulic pump 5 is used instead of the basic tilt angle control signal set by the basic tilt angle control amount setting means 6. 1, Set the maximum tilt angle control signal that maximizes the tilt angle of the second hydraulic pump 5 2 as the tilt angle control signal, and in step A 60, set the tilt angle control signal to the first hydraulic pump 5. 1, Output to the second hydraulic pump 52.

As described above, the pump displacement angle control means 3 controls the displacement of the first hydraulic pump 51 and the second hydraulic pump 52 based on the detection signals from the pressure sensors 72, 73, 74, 75. A control signal corresponding to the angle control amount is calculated, and this control signal is used as an operation amount signal from the operating member 54 and an engine speed sensor 71 Correction is performed based on the detection signal to calculate a corrected tilt angle control amount. Then, a control signal corresponding to the corrected tilt angle control amount is output to the first hydraulic pump 51 and the second hydraulic pump 52.

Thus, the tilt angles of the first hydraulic pump 51 and the second hydraulic pump 52 are controlled to the control amount calculated by the pump tilt angle control means 3, and set to a predetermined pump displacement. As a result, the pump flow rates from the first hydraulic pump 51 and the second hydraulic pump 52 are adjusted.

Therefore, according to the control device and control method for a construction machine according to the present embodiment, extra horsepower consumption when the stick 104 descends under its own weight is reduced, so that power loss is reduced, fuel consumption is improved, and heat loss is reduced. There is an advantage that it can be achieved.

Also, since the pressure in the hydraulic cylinder 106 for driving the stick does not increase and the temperature of the hydraulic cylinder 106 for driving the stick does not increase, it is possible to improve the heat balance and the cooling performance. There is also the advantage of being able to do so.

Furthermore, since there is no extra back pressure generated when the stick 104 descends under its own weight, there is no need for extra horsepower, and there is an advantage that work efficiency is improved.

In the above embodiment, the self-weight drop control of the stick 104 has been described. However, the present invention is not limited to this. The same weight drop control can be performed for the bucket and the bucket 108 as well.

In the above-described embodiment, in the case of the self-weight drop control of the stick 104, the diameter of the C_T throttle 9 is set to be larger than that of the conventional one so as to be able to cope with the case where the engine speed is maximum. The stroke amount of the spools constituting the control valves 60 and 64 can be changed according to the engine speed. Thus, the C—T opening area is adjusted. However, the method of adjusting the C−Τ opening area is not limited to this. For example, instead of changing the diameter of the C−Τ throttle 9, the control valve 6 may be used. The position of the C-throttle 9 formed on the spools constituting the control valves 60 and 64 may be changed. Only one stroke may be changed. Further, a spool is provided separately from the control valves 60 and 64 in the oil passage between the stick driving hydraulic cylinder 106 and the reservoir tank 70 and downstream of the position where the control valves 60 and 64 are disposed. A control valve configured as a valve is provided, and as the engine speed increases, the opening area of the oil passage between the stick driving hydraulic cylinder 106 and the reservoir tank 70 (C 一 opening area) increases. Alternatively, the stroke amount of the spool constituting the control valve may be controlled so as to be smaller.

With such a configuration, the opening area of the bypass passage is adjusted during the self-weight drop control of the stick 104, and the bypass flow rate of the hydraulic oil flowing through the bypass passages 6 1b and 66 c may change. Therefore, it is possible to prevent the pressure of the hydraulic oil downstream of the bypass passage used in the negative flow control from being changed.

In the above-described embodiment, the spool is moved by the pilot pressure. However, the present invention is not limited to this, and the spool may be moved by an electromagnet or the like.

Further, in the above-described embodiment, the case where the present invention is applied to the control device of the construction machine which performs the negative flow control is described. However, the present invention is applied to the control device of the construction machine which performs the positive flow control. May be. Industrial applicability As described above, a control device and a control method for a construction machine according to the present invention include a construction machine having a stick or the like and performing an operation of lowering the work machine by its own weight.

(Eg, hydraulic shovels), and is particularly suitable for construction machinery that supplies hydraulic oil discharged from an engine-driven hydraulic pump during a hydraulic rush to drive a work machine.

Claims

The scope of the claims

1. An operating member (54) operated by an operator;

Hydraulic pumps (51) and (52) driven by the engine and discharging hydraulic oil in the tank;

Hydraulic actuators (105), (106), (107) driven by hydraulic oil discharged by the hydraulic pump;

A hydraulic oil discharge passage (66b), (69) for discharging hydraulic oil from the hydraulic actuator to the tank from one night;

A control valve (60), (64) interposed in the hydraulic oil discharge passage (66b), (69) for controlling the flow rate of hydraulic oil discharged through the hydraulic oil discharge passage; An engine speed sensor (71) for detecting a rotational speed; and control means (1) for controlling the control valve to adjust the opening area of the hydraulic oil discharge passage based on the operation amount of the operating member (54). With

The control means (1) controls the control valves (60), (64) in consideration of the engine speed detected by the engine speed sensor (71). Machine control device.

2. Hydraulic oil supply passages (61a) and (66a) for supplying hydraulic oil from the hydraulic pump to the hydraulic actuator are provided.

The opening area of the hydraulic oil discharge passages (66b) and (69) is such that the operation amount of the operating member (54) is the largest and the engine speed detected by the engine speed sensor (71) When the hydraulic oil discharge passage (66 b), ( 6 9) The construction machine according to claim 1 is set to be discharged through Control device.

3. The opening area of the hydraulic oil discharge passages (66b) and (69) decreases as the engine rotation speed detected by the control means (1) and the engine rotation speed sensor (71) decreases. The control of a construction machine according to claim 1, characterized in that said control valve (60), (64) is controlled as described above.

4. The control device according to claim 1, wherein the control means (1) corrects a control amount for the control valves (60) and (64) by a correction coefficient that decreases as the engine speed decreases. A control device for a construction machine according to any one of the preceding claims.

5. The control means (1) Force The control valves (60) and (64) are controlled so that the opening areas of the hydraulic oil discharge passages (66) and (69) change according to the engine speed. The control device for a construction machine according to claim 1, wherein the control amount is set.

6. The hydraulic oil that has not been supplied to the hydraulic actuators (105), (106), and (107) via the control valves (60), (64) is returned to the tank by the return valve. With passageways (6 1 b), (6 6 c)

The control valves (60) and (64) are arranged in the bypass passage and configured to adjust the opening area of the bypass passage.

The control means (1) force

A basic tilt angle for controlling a discharge amount from the hydraulic pumps (51), (52) based on a characteristic substantially inversely proportional to a flow rate of the hydraulic oil in the bypass passage. Turning angle control amount setting means (6); When the operation amount of the operation member (54) is maximum and the engine rotation speed detected by the engine rotation speed sensor (71) is not the maximum, the discharge flow rate from the hydraulic pump is maximized. The tilt angle control amount correcting means (7) for correcting the basic tilt angle control amount set by the basic tilt angle control amount setting means (6). 2. The control device for a construction machine according to claim 1.

7. An operating member (54) operated by the operator,

Hydraulic pumps (5 1), (5 2) driven by the engine and discharging hydraulic oil in the tank;

A hydraulic oil discharge passage (66b), (69) for discharging hydraulic oil to the tank from the hydraulic actuator overnight;

Control valves (60) and (64) interposed in the hydraulic oil discharge passages (66 b) and (69) for controlling the flow rate of hydraulic oil discharged through the hydraulic oil discharge passage; An engine speed sensor (71) for detecting a rotation speed; and a control means (1) for controlling the control valve to adjust an opening area of the hydraulic oil discharge passage based on an operation amount of the operation member (54). A method for controlling a construction machine comprising:

A detection step for detecting the engine speed by the engine speed sensor (71);

A control step of controlling the control valves (60) and (64) by the control means (1) in consideration of the engine rotation speed detected in the detection step. Method.

8. In the control step, when the operation amount of the operation member (54) is the maximum and the engine rotation speed detected in the detection step is the maximum, the hydraulic pump is connected to the hydraulic actuator (105). ), (106), (107) Hydraulic oil at a flow rate corresponding to the maximum supply flow rate of the hydraulic oil supplied through the hydraulic oil supply passages (61a), (66a) The control valve (60), (64) is controlled such that the oil is discharged through the hydraulic oil discharge passage (66, 69). Construction machinery control method. 9. In the control step, the control valve (6) is set so that the opening area of the hydraulic oil discharge passages (66b) and (69) decreases as the engine rotation speed detected in the detection step decreases. 8. The method for controlling a construction machine according to claim 7, wherein (0) and (64) are controlled. 10. The control step, wherein the control amount for the control valves (60) and (64) is corrected by a correction coefficient that decreases as the engine rotation speed decreases. A method for controlling a construction machine according to the item.

1 1. In the control step, the control valve (6 0), (6 0), so that the opening area of the hydraulic oil discharge passage (66 b), (69) changes in accordance with the engine speed

The control method for a construction machine according to claim 7, wherein the control amount according to (64) is set.

1 2. Hydraulic oil not supplied to the hydraulic actuators (105), (106) and (107) via the control valves (60) and (64) is returned to the tank. With passages (61b) and (66c) The control valves (60) and (64) are arranged in the bypass passage and configured to adjust the opening area of the bypass passage.

In the control step,

A control valve for controlling the discharge flow rate from the hydraulic pumps (51) and (52) based on a characteristic that is substantially inversely proportional to the flow rate of the hydraulic oil in the bypass passages (61b) and (66c). Set the basic tilt angle control amount,

When the operation amount of the operation member (54) is the maximum and the engine rotation speed detected in the detection step is not the maximum, the basic tilt angle control is performed so that the discharge flow rate from the hydraulic pump becomes the maximum. 8. The control method for a construction machine according to claim 7, wherein the amount is corrected.