JP2996891B2 - Construction machine control device and control method thereof - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for a construction machine and a method for controlling the same, and more particularly to a control device for controlling an engine, a hydraulic pump, and a hydraulic circuit mounted on a construction machine such as a construction vehicle. TECHNICAL FIELD The present invention relates to a control device and a control method for a construction machine having good operability and maneuverability.

[0002]

2. Description of the Related Art Conventionally, a construction vehicle employs a hydraulic circuit as shown in FIG. The hydraulic circuit includes a variable displacement pump 11 (hereinafter, referred to as a pump 11) driven by the engine 1 and a pilot pump 81. The swash plate angle of the pump 11 is controlled by a servo piston 12, and the pump 11 is connected to a servo control valve 200 for controlling the operating pressure of the servo piston 12.
An operation unit 200a of the servo control valve 200 is provided with a neutral control valve 210 (hereinafter, referred to as an NC valve 210).
, The cut-off valve 220 and the variable torque control valve 230 are connected in series. A pipe 201 a branched from a discharge pipe 201 of the pump 11 is provided with a cutoff valve 22.
0 and the operation unit of the variable torque control valve 230. A pipe 222 branched from a discharge pipe 221 of the pilot pump 81 includes a variable torque control valve 230, a cutoff valve 220, and an NC valve 2.
Through 10, it is connected to the operation unit 200 a of the servo valve 200. The engine rotation sensor 3 for detecting the rotation speed of the engine 1 is connected to the control device 240. Control device 2
40 is connected to the variable torque control valve 230.

The discharge line 201 of the pump 11 is connected to a direction switching valve 250. The direction switching valve 250 is connected to the cylinder 260 via the pipes 251a and 251b, and is connected to the jet sensor (pressure detecting unit) 253 via the pipe 252. The jet sensor 253 is connected to the drain path 254. Further, the discharge pipe 22 branched from the discharge pipe 221 of the pilot pump 81
3 is connected to the pressure proportional control valve 270, and the operation lever 271
Are connected to the pressure proportional control valve 270. The pressure proportional control valve 270 is connected to the operation unit of the direction switching valve 250 via the lines 272a and 272b. 254 is a relief valve.

Next, the operation will be described. NC valve 21
0 indicates the pressure detected by the jet sensor 253 in line 2
56 to the operation unit on one side, the jet sensor 2
The pressure detected in the drain passage 254 on the downstream side of 53 is input from the pipe 257 to the operation unit on the other side, and is switched by the differential pressure before and after the jet sensor 253. When the directional control valve 250 shown in the drawing is in the neutral position, all the discharge flow rate of the pump 11 is drained from the drain passage 254 to the tank 258 through the jet sensor 253, so that the pressure downstream of the jet sensor 253 increases, and the NC valve 210 Is the port position 210b shown in the figure. Thereby, the servo valve 200 is moved to the port position 200c.
Then, the servo piston 12 is moved to the left side in the figure, and the flow rate of the pump 11 is reduced. This further reduces the energy loss at the neutral position.

Next, the operation when the operator switches the direction control valve 250 to any one will be described. At this time, since no oil flows to the jet sensor 253, the NC valve 210 is at the port position 210a. Further, a rotation speed signal from the engine rotation sensor 3 of the engine 1 is always input to the control device 240, and a command signal is sent from the control device 240 in accordance with the rotation speed signal to the operating section 230a of the variable torque control valve 230. Is input to Note that the discharge pressure of the pump 11 is input to the operation unit 230b of the variable torque control valve 230. Therefore, in response to the command signal of the engine speed signal,
When the discharge pressure of the pump 11 is low, the port position of the variable torque control valve 230 shown in the figure is at the position of 230c, and the cutoff valve 220 is at the position of 220a. The NC valve 210 is at the position 210a as described above. Therefore, the pilot pressure from the pipe 222 is input to the operation section 200a of the servo control valve 200, so that the servo control valve 200 switches to the position 200b. This allows
The oil on the head side of the servo piston 12 is drained, and the oil from the pipe 221 flows into the bottom side, and the servo piston 12 moves to the right to increase the pump discharge amount.

On the contrary, when the discharge pressure of the pump 11 is high in response to the command signal of the engine rotation speed signal, the variable torque control valve 230 switches to the position 230d, and the pilot Since the pressure is not input to the operation section 200a of the servo control valve 200, the servo control valve 200 switches to the position of 200c. As a result, the oil from the pipe 221 flows into the head side of the servo piston 12, the oil on the bottom side is drained, and the servo piston 12 moves to the left to reduce the pump discharge amount.

[0007] The cutoff valve 220 is usually
Since the force of the spring 220b is set to be large for one discharge pressure, the spring 220b is located at the position 220a. Pump 1
When 1 becomes the maximum pressure, the position is switched to the position of 220c, and cutoff control for further reducing the flow rate of the maximum pressure is performed. The variable torque control valve 230 adjusts the engine rotation speed N and the discharge pressure P of the hydraulic pump so that the discharge flow rate Q [Q =
q (cc / rev) · N] is controlled to be constant, and the absorption horsepower of the hydraulic pump is controlled on a constant line of substantially equal horsepower (P · Q = constant).

In the above configuration, recently, an operator operates a selection switch (not shown) attached to the controller 240 in accordance with a work site to select an engine torque and a pump absorption torque so that the engine torque and the pump absorption torque can be used under optimum conditions. Has been. For example, a heavy excavation mode used at the rated output point of the output of the engine as shown in FIG. 23 used for work requiring more work amount and power, an excavation mode used for normal excavation loading work, FIG. 24 shows a setting mode for adjusting at a 75% partial output point of the output of the engine used during work, and a 50% partial output of the engine output shown in FIG. 25 used at the time of work requiring fine operation. There is a fine operation mode and the like to match with points. At this time, the engine torque and the pump absorption torque (indicated by a broken line A) are matched at one point of the rated output point of the engine output as shown in FIG. 26, and as shown in FIG. (Indicated by (b)) is equal horsepower control, and as shown in FIG. 28, pump absorption torque (indicated by a two-dot chain line (c)) is constant torque control. Further, as disclosed in Japanese Utility Model Application Laid-Open No. 58-133665, in a hydraulic excavator, when excavating with an arm while lowering the boom, the front of the vehicle body is likely to float due to the reaction force of the arm excavating force of the arm cylinder, The pressure on the head side of the boom cylinder is set low. In a conventional variable displacement hydraulic pump,
Servo piston 12 that sets the capacity of the pump sets a speed that allows for stability within a range that balances the inertia of the driver of the hydraulic pump with the operation of the servo piston 12 so that hunting does not occur. So that it can be taken. Further, as another function, the cut-off function shown in FIG. 29 for reducing the energy loss at the time of relief of the hydraulic circuit or the cut-off function (indicated by the dotted line d) is stopped to reduce the pressure near the relief pressure. There is a cutoff release function shown in FIG.

[0009]

However, since there is a great difference in operation skills between a skilled person and a beginner, as described above, the operator operates the work mode switch according to the work site to perform the heavy excavation mode, the excavation mode, In a construction machine that selects one of the normal mode and the fine operation mode, if the mode is set for a beginner-side operator, the skilled person feels insufficient,
Further, if the setting is made for a skilled operator, it is felt that it is difficult for a completely beginner to handle. In addition, the operator selects the engine torque and the pump absorption torque using the work mode switch according to the work site.
6, in the heavy excavation mode as shown in FIG. 27 and FIG. 28, the engine torque and the pump absorption torque are generally matched at one point (near). For this reason,
When the load is applied to the pump, the pressure applied to the pump or the discharge volume of the pump is quickly reduced to adjust the pump absorption torque, so that the working speed is reduced and the engine rotates even if the engine is loaded. Since the speed does not decrease, the tone of the engine does not change. Thereby, a skilled operator cannot perform high-speed work during excavation or the like, and cannot sense the magnitude or strength of a change in the workload during work such as excavation, so that the tenacity of the vehicle in the work state, or There is a problem that you cannot feel the power.

Further, when the arm is excavated together with the lowering of the boom, the pressure on the head side of the boom cylinder is set low to prevent the body from floating in front of the vehicle due to the reaction force of the arm excavation. When you want to do,
The boom escaped upward and heavy excavation was not possible. Also,
Since the pressure on the head side of the boom cylinder is set low, the vehicle's tension force is insufficient when escaping from soft ground,
Lack of escape. In addition, when the work speed or the turning speed is set for the beginner-side operator in the same manner as described above, even if the work mode switch is selected according to the work site, the maximum speed of the working machine or the turning is the same. It is set to a predetermined speed. For this reason, the operator operates the accelerator lever to adjust the working machine or turning speed according to the engine speed in accordance with his or her skill. There is a problem that the working speed or the turning speed is slow and the construction machine "feels as a slow-moving machine".

When the time for changing the discharge volume of the pump is set, the responsiveness is high at a high pressure, and accordingly, the responsiveness of the pump is set within a range where hunting does not occur. For this reason, at low pressure, the response becomes slow as shown in FIG. 14 (standard broken line), and the skilled operator follows the change of the operating lever to the change of the operation lever at the time of work including a lot of low load and high load work. In addition to the above, there is a problem that a construction machine "feels as a slow-moving machine". Furthermore, conventionally, the structure is complicated because a cut-off valve for controlling electric and hydraulic pressures is provided, and when the pressure reaches a predetermined pressure, a cut-off for further reducing the flow rate is performed. .

The present invention has been made in view of the above-mentioned conventional problems, and relates to a control device and a control method for a construction machine, and more particularly, to an engine, a hydraulic pump, and a hydraulic device mounted on a construction vehicle or the like. Provided is a control device and a control method for a construction machine of a construction vehicle having improved stiffness of an engine, improved working speed or turning speed by controlling a circuit, or excellent in workability and maneuverability even for beginners and skilled workers. With the goal.

[0013]

[0014]

[0015]

[0016]

[0017]

[0018]

According to a first aspect of the present invention, there is provided a control apparatus for a construction machine and a control method therefor, comprising: an engine; a variable displacement pump driven by the engine; A pump output control means for controlling the product of the load pressure and the discharge capacity acting on the variable displacement pump to be substantially constant, and a working device operated and operated by an actuator receiving pressure oil from the pump; In a control device for a construction machine having a selection means for selecting an output torque of an engine and an absorption torque of a variable displacement pump according to the site or work content, a discharge volume of a pilot pump generating pilot pressure oil and a discharge volume of the variable displacement pump are varied. Servo control means for controlling the swash plate to be, and active mode selection / cancellation means for performing powerful work such as heavy excavation, And control means for outputting a command signal by the active mode selection, positive when the load pressure of the response speed of the pilot pressure from the pilot pump to the servo control means is variable pump pump is lower by the signal
Pump response speed, and the pump load pressure
And a pump response speed switching means for sequentially lowering and varying the pump response speed.

[0019]

In the second invention, the output torque of the engine is selected according to the work site or the work content,
In a control method for a construction machine in which the output torque of an engine is controlled by matching with a load acting on a variable displacement pump to be driven, the rated torque point of the engine is set as an aim value by selecting an active mode, and The increase is to move the engine output torque line to the higher torque side, and the load is reduced to return the engine output torque line to the rated torque point.

[0021] In the third invention mainly the second invention,
A predetermined width is provided on the engine output torque line from the vicinity of the rated torque point to the high torque side, and when the load is continuous, output is performed at the width end on the high torque side.

[0022]

[0023]

In the fourth invention, the output torque of the engine is selected according to the work site or the work content,
A construction machine having a working machine driven by a plurality of actuators in which output torque of an engine is controlled by matching with a load acting on a driven variable displacement pump and receives pressure oil from the pump via a directional control valve. Control method, the pump is selected by selecting the active mode.
When the load pressure is low, the response speed of the pump is increased, and the response speed of the working machine is increased.

[0025]

According to the above configuration, the active mode according to the skill of the skilled person and the standard mode according to the skill close to the beginner are set, so that the work mode according to the skill can be selected. For example, if the active mode is selected, the active mode adjusts the absorption torque of the pump at the rated output torque point at the rated output of the engine, and when the work load increases and the load is applied to the pump, the absorption torque generated by the pump is reduced. It moves along a torque curve within a predetermined range from the rated output torque point of the engine. For this reason, the output of the engine changes in output torque along the torque curve, the rotational speed of the engine decreases, the tone of the engine changes, and the operator can understand that a load is applied to the engine.

[0026]

[0027]

Further, when changing the discharge volume of the pump, the time for changing the discharge volume in accordance with the response at high pressure is set, and the responsiveness at high pressure is set even at low pressure by changing the throttle. , Even at low pressure
As shown by a solid line, the responsiveness is increased, the operator's satisfaction is improved even for a skilled operator, and the cycle time is shortened to increase the amount of work.

Further, since the cut-off valve uses a valve for controlling the torque of the pump, a dedicated cut-off valve can be eliminated and the structure is simplified.

[0030]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of a variable displacement pump control device and control method according to the present invention will be described in detail with reference to the accompanying drawings. First, FIG. 1 is an overall block configuration diagram of the first embodiment, FIG. 2 is an overall configuration diagram of the first embodiment, FIG. 3 is a partially enlarged view mainly showing an engine and a pump section of FIG. 2, and FIG. A description will be given with reference to a partially enlarged view mainly including the control valve section 2. 1, an engine 1 mounted on a construction machine such as a hydraulic excavator (not shown), a governor controller 2 for controlling the rotation speed and output of the engine 1, an engine rotation sensor 3 for detecting the rotation speed of the engine 1, and an engine 1 and a variable displacement pump unit 10 (hereinafter, referred to as a pump unit 10) for discharging a flow rate, a control valve unit 40 for controlling a fluid discharged from the pump unit 10, and powerful work such as heavy excavation. An active mode switching unit 60 that switches when an active mode to be performed is selected;
An actuator unit 70 that receives pressure oil via the control valve unit 40 and operates a work machine (not shown), an operation unit 80 that supplies pressure oil that controls the pump unit 10 and the control valve unit 40,
Pressure sensor 90 for detecting pressure discharged by pump unit 10
And a work mode setting switch unit 91 for setting a work mode in accordance with work conditions or a site, and commands from the governor controller 2, the engine rotation sensor 3, the pressure sensor 90, and the work mode setting switch unit 91, and the pump unit 10, active mode switching unit 60, operation unit 80
And a control device 100 that outputs a control command to the governor controller 2. In FIG. 1, a dotted line (α) indicates a command from the control device 100 to the active mode switching device 60 in the first embodiment, and (β) indicates an active mode from the switches 67 and 163 in a third embodiment described later. The instruction to the switching device 60 is shown.

1, 2 and 3, the engine 1 is provided with a fuel injection pump 4 and a governor 5.
The governor 5 is driven by a governor motor 6, and the governor motor 6
Is detected by the governor position sensor 7. The throttle amount setting device 8 includes a dial 8a and the dial 8a.
And a potentiometer 8b which is turned.
The governor controller 2 includes a first throttle signal output from the throttle amount setting device 8 and a control device 10 described later.
The governor motor 6 is compared with the second throttle signal output from 0, and the governor motor 6 is driven based on the smaller one of the signals. The governor motor 6 controls the output torque of the engine 1 according to the operation mode as illustrated in FIGS. 26, 27, and 28.

The pump unit 10 includes a variable displacement pump 11
(Hereinafter referred to as pump 11) and servo piston 12
, A servo control valve 13, a torque variable control valve 14 (hereinafter referred to as a TVC valve 14), an electromagnetic switching valve 61 for an output torque of an active mode switching unit 60 which operates in an active mode described later in detail, and a variable displacement pump. Servo response switching valve 62 (hereinafter referred to as servo response switching valve 62), and servo response electromagnetic switching valve 63
It is composed of The pump 11 is connected to the servo piston 12, and the pressure oil acting on the servo piston 12 changes the swash plate angle to change the discharge volume (cc / rev). The pressure of the oil supplied to the servo piston 12 is controlled by the servo control valve 13, the TVC valve 14, and the output torque electromagnetic switching valve 61. A change in the swash plate angle of the pump 11 is detected by the swash plate angle sensor 101 and sent to the control device 100. Although details will be described later, the servo control valve 13 and the TVC valve 14 perform matching control of the engine output torque based on the pressure acting on the pump, the engine rotation speed, and the absorption torque of the pump. Cutoff control by value,
The cutoff function release control is performed based on the current value.

1, 2 and 4, the control valve section 40
The directional control valve 41, the pressure compensating valve 42, the shuttle valve 43, the two-stage relief valve 44, the two-stage safety valve 45 with the suction valve, and the two-stage safety valve 46 operate in an active mode which will be described in detail later. And a directional control valve electromagnetic switching valve 64 of the active mode switching section 60. The direction control valve 41 has spool operation units 41a and 41b at both ends for controlling the direction of the flow rate from the pump 11. The spool operation units 41a and 41b are provided with a boom direction control valve 41.
d, mounted on both ends of the arm direction control valve 41e, the bucket direction control valve 41f, and the turning direction control valve 41g. Further, the spool operation units 41a and 41b move a spool (not shown) by a predetermined amount of stroke S in response to a pilot pressure from each of the proportional pressure solenoid valves described later, which are operated by the operator, and are proportional to the operation amount operated by the operator. The flow rate is supplied to the actuator unit 70.

The spool operating portion 41b of the boom direction control valve 41d and the arm direction control valve 41e includes:
In order to greatly change the stroke of a spool (not shown) so as to increase the operation speed of arm excavation, boom lowering, and the like, two-stage spool operation units 41ba and 41bb are provided. The spool operation unit 41b is operated in the standard mode Sw.
At this time, the two-stage spool operating portion 41bb receives the pressure from the direction control valve electromagnetic switching valve 64, regulates the amount of movement of the spool (not shown), and changes the maximum stroke to a small value.
Further, in the active mode Aw, the pressure from the directional control valve electromagnetic switching valve 64 is not received by the two-stage spool operating portion 41bb, and the maximum stroke of the spool (not shown) is greatly changed. Each direction control valve is provided with a throttle 41h, and the pressure oil passing through the throttle 41h is supplied to the shuttle valve 4h.
The maximum of the pressure acting on each directional control valve is taken out via 3. This pressure is supplied to the servo control valve 13 and the pressure compensating valve 42. The servo control valve 13 increases and decreases the discharge amount of the pump 11, and the pressure compensating valve 42 maintains the pressure acting on each cylinder.

In FIG. 4, the two-stage relief valve 44 is mounted between the pump 11 and the direction control valve 41 to increase the pressure of the circuit in the active mode Aw.
Also, a two-stage safety valve 45 with a suction valve and a two-stage safety valve 46
Has a normal pressure (first stage) and a high pressure (second stage). In the active mode Aw, it is necessary to maintain the relief set pressure of the first stage and further increase the excavating force in the active mode Aw. When the one-touch excavation power is increased, the second stage has a high relief set pressure. In this embodiment, the two-stage safety valve 45 with a suction valve is mounted on the cylinder head side 71a of the boom cylinder 71 such as when the boom is lowered. This avoids a vacuum on the cylinder head side 71a of the boom cylinder 71. The two-stage safety valve 45 with the suction valve and the two-stage safety valve 46 are in the active mode Aw.
The first stage without receiving the pressure from the fourth stage, and the second stage upon receiving the pressure from the directional control valve electromagnetic switching valve 64 when the one-touch excavation force is increased.

In FIGS. 2, 3 and 4, the active mode switching unit 60 includes an output torque electromagnetic switching valve 61, a servo response switching valve 62, and a servo response electromagnetic switching valve 63.
And a directional control valve electromagnetic switching valve 64. When the active mode Aw is selected, the output torque electromagnetic switching valve 61 is switched in response to a command from the control device 100, shuts off the hydraulic pressure from the pilot pump 81 by the servo control valve 13, and discharges the pump 11. The pump output torque is increased by increasing the amount. When the active mode Aw is selected, the servo response electromagnetic switching valve 63 is at the position shown in the drawing (disconnected) without receiving a command from the control device 100, and shuts off the hydraulic pressure from the pilot pump 81. In the active mode Aw, the servo response switching valve 62 controls the response of the speed at which the swash plate angle of the pump 11 changes by the discharge pressure of the pump 11 to be faster.

One of the directional control valve electromagnetic switching valves 64 is
Boom directional control valve 41d and arm directional control valve 4
The hydraulic pressure from the pilot pump 81 is sent to the spool operation section 41b of 1e to greatly change the maximum stroke of the spool, thereby increasing the flow rate sent to the actuator section 70. The other branch is a two-stage safety valve 45 with a suction valve.
Then, the power is sent to the two-stage safety valve 46 to increase the force of the actuator unit 70 to increase the excavating force of a working machine (not shown). In the above embodiment, the directional control valve electromagnetic switching valve 6
4 shows one, but a plurality may be provided as in the second embodiment.

In FIG. 4, the actuator unit 70
A work machine such as a bucket or a blade is attached to a link mechanism of a construction machine (not shown) and drives a work machine such as a bucket and a blade. In this embodiment, a boom cylinder 71, an arm cylinder 72, a bucket cylinder 73, and a turning motor 74 are mounted.

In FIGS. 2 and 4, an operating section 80 includes a pilot pump 81 serving as a pilot hydraulic pressure source, a relief valve 82 for adjusting the pilot hydraulic pressure, and a boom for controlling a boom direction control valve 41d. Proportional pressure solenoid valve 8
3, an arm proportional pressure solenoid valve 84 for controlling the arm direction control valve 41e, a bucket proportional pressure solenoid valve 85 for controlling the bucket direction control valve 41f, and a swing for controlling the swing direction control valve 41g. Proportional pressure solenoid valve 86
Consists of Boom proportional pressure solenoid valve 83, arm proportional pressure solenoid valve 84, bucket proportional pressure solenoid valve 85
Each of the proportional pressure solenoid valves of the turning proportional pressure solenoid valve 86 outputs a proportional pressure through the control device 100 according to a signal of an operation amount of an electric lever (not shown) operated by an operator. The pilot pressure output from the proportional pressure solenoid valve in accordance with the operation amount is controlled by the spool operating section 4 of each directional control valve.
1a and 41b.

The pressure sensor 90 detects the pressure discharged from the pump unit 10, and the detected pressure signal is sent to the control unit 100 and used to control the discharge amount of the pump unit 10. The work mode setting switch unit 91 is a switch for setting a work mode in accordance with work conditions or a site. In the present invention, a switch for selecting an active mode Aw and a standard mode Sw according to his / her own skill is provided. Has been established. The safety valve excavation force up switch 92 is attached to the control device 100, and when the one-touch excavation force up control for increasing the excavation force is selected, the relief pressure is set to the set high pressure.

The control device 100 receives commands from the governor controller 2, the engine rotation sensor 3, the pressure sensor 90 and the work mode setting switch unit 91 and outputs control commands to the pump unit 10, the operation unit 80 and the governor controller 2. I do. In the present invention, in particular, when the active mode Aw is selected by the work mode setting switch section 91, the output torque electromagnetic switch valve 61 and the direction control valve electromagnetic switch valve 64 are commanded by the pressure signal from the pressure sensor 90. Is output, and no command is output to the electromagnetic switching valve 63 for servo response. This increases the discharge amount of the pump 11 and speeds up the response, and cancels the cut-off to increase the pressure. Standard mode S with work mode setting switch unit 91
When w is selected, a command is not output to the output torque electromagnetic switching valve 61 and the direction control valve electromagnetic switching valve 64 by the pressure signal from the pressure sensor 90, and the servo response electromagnetic switching valve 63 is not output. A command is output to make the discharge amount and response of the pump 11 standard, and the pressure is reduced by cutting off.

Next, referring to FIG. 3, the servo control valve 13, servo response switching valve 16, and TVC valve 14 will be described. The swash plate angle of the pump 11 is controlled by a servo piston 12. The servo piston 12 is connected to a conduit 22, a servo response switching valve 62, and a conduit 22.
It is connected to a servo control valve 13 for supplying a control pressure via a. The servo control valve 13 is connected to the discharge line 2 of the pump 11.
A conduit 21b from a conduit 21a branching from 1;
T for controlling the output of the pump 11 to be approximately equal horsepower
It is connected to the VC valve 14 via a conduit 23. Further, the operating portion 13a at one end of the servo control valve 13 is connected to a conduit 21a via a conduit 21a branched from a discharge conduit 21 of the pump 11.
In addition, the operating portion 13aa at one end is also connected to the conduit 24 from the discharge line 25 of the pilot pump 81 via the output torque electromagnetic switching valve 61. The other end 13 b of the servo control valve 13 is connected to the pipe 2 via the shuttle valve 43 when the maximum pressure of the pressure applied to the actuator 70 is
5 are connected. A spring 13c is provided on the other end side so as to contact a spool (not shown).

An operation section 62 at one end of the servo response switching valve 62
a is a conduit 21 branching from a discharge line 21 of the pump 11.
a to the conduit 21d, and the operating part 62b at the other end,
It is connected to the discharge line 26 of the pilot pump 81 via the servo response electromagnetic switching valve 63. In the present invention, particularly, when the active mode Aw is selected by the work mode setting switch section 91, the control device 100 does not output a command to the servo response electromagnetic switching valve 63, and the servo response switching valve 62 11 is the operating unit 62a at one end.
Is controlled between the variable throttle port 62e and the non-throttle port 62f to speed up the response of the pump 11. When the work mode setting switch unit 91 is selected in the standard mode Sw, the control device 100 outputs a command to the servo response electromagnetic switching valve 63, and the servo response switching valve 62 sets the discharge pressure of the pilot pump 81 to the other end. Operation unit 62b
And is controlled by the fixed throttle port 62g to standardize the response of the pump 11.

The operation section 14a at one end of the TVC valve 14
A conduit 21 branching from a discharge line 21 of the pump 11
A conduit 21e further branched from a is connected. This T
The solenoid operating portion 14b at one end of the VC valve 14 is connected to the control device 100 via an electric circuit 27. This T
At the other end of the VC valve 14, two springs 14c and 14d are provided, and the springs 14c and 14d
Abuts against the pressing member 19 connected to the piston 12b. The springs 14c and 14d are deflected by being pushed by a piston (not shown) of the TVC valve 14, and press the pressing member 19 to operate the piston 12b to control the swash plate of the pump 11. With this control, the discharge capacity of the pump 11 is variable. In the above embodiment, using two springs,
Although the control is performed so that the power becomes substantially equal, the solenoid may be made variable so that the power becomes equal.

A low control pressure from the pump 11 is applied to the operating section 14a at one end of the TVC valve 14 shown in FIG.
When the pressure is applied to the pump 11, that is, when the pressure of the load on the pump 11 is low, the TVC valve 14 is at the drain position 14e due to the spring force of the springs 14c and 14d, and also the operating portion 13a of the servo control valve 13 When a low control pressure from the pump 11 is being input from the conduit 21c, the servo control valve 13 is also at the drain position 13d. Therefore, the control pressure of the pressure chamber 12a of the servo piston 12 is connected to the tank 29 through the conduit 22, the servo response switching valve 62, the conduit 23, the servo control valve 13, and the conduit 28. At this time, the piston 12b is
c, the swash plate of the pump 11 is pushed in a direction to increase the discharge capacity.

Next, when a high control pressure from the pump 11 is input to the operation portion 14a of the TVC valve 14 from the conduit 21e, the position becomes 14f against the springs 14c and 14d. Pump 1 also for 13a
Since the high control pressure from 1 is input from the conduit 21c, the position becomes 13e against the spring 13c. The pump 1
The control pressure from 1 is transmitted from the conduits 21a to 21b and from the conduit 21f to the pressure chamber 12a of the servo piston 12 via the TVC valve 14, the conduit 23, the servo control valve 13, the servo response switching valve 62 and the conduit 22. It has become.

As described above, when the discharge pressure of the pump 11 increases, the control pressure passing through the TVC valve 14, the servo control valve 13, and the servo response switching valve 62 is increased by the discharge pressure. And the piston 12b moves rightward against the spring 12c to reduce the swash plate angle of the pump 11 and discharge volume q (cc / r
ev) is controlled to be small. Further, when the discharge pressure of the pump 11 decreases, the servo piston 12 operates in the opposite manner as described above, so that the swash plate angle of the pump 11 is increased to increase the discharge volume. When the servo piston 12 is pushed to the right to the maximum and comes into contact with the end face of the case via the spring 12c, the pump 11 is at the minimum swash plate position, and the discharge volume of the pump 11 is the minimum volume qmin (cc / cc).
rev). On the contrary, when the servo piston 12 is pushed to the left to the maximum and comes into contact with the case, the pump 11 is at the maximum swash plate position, and the discharge volume of the pump 11 is the maximum volume qma.
x (cc / rev).

The operation section 14a at one end of the TVC valve 14 has
A solenoid operating unit 14b is provided at one end in parallel, receives a command from the control device 100 via the electric circuit 27, and performs matching control between engine output and pump absorption torque, which will be described later, and cutting. Off control or cutoff function release control is performed.

The output torque electromagnetic switching valve 61 is switched by a command from the control device 100 in the active mode Aw, and supplies the hydraulic oil from the pilot pump 81 to the operating section 13aa of the servo control valve 13 in the standard mode Sw. Operation of the servo control valve 13
Is connected to the tank 29. As a result, the servo control valve 13 becomes similar to the case where the discharge pressure of the pump 11 decreases, and the discharge amount of the pump 11 increases when the active mode Aw is selected by the work mode setting switch unit 91.

Next, the operation of the first embodiment of the present invention will be described. First, the discharge control of the pump will be described. When the engine 1 is started and the operator performs a work, a pressure applied to the actuator 70 from the pump 11 at the time of the work is generated by the load acting on the actuator 70. The pressure during the work is applied to the discharge pipe 21 of the pump 11 as the pump load pressure Pa, and the actuator unit 70 has a one-step lower pressure after being throttled by the direction control valve 41 acting as the actuator pressure Pb. Therefore, the pipe 21 branched from the discharge pipe 21 of the pump 11
a, the pump load pressure Pa is changed to the operation unit 13a of the servo control valve 13 and the operation unit 13b of the servo control valve 13 at the same time.
It is also told. On the other end side of the servo control valve 13, the actuator pressure Pb acts on the other end portion 13b through the shuttle valve 43 and the pipe 25, and the spring 1
The spring force of 3c is acting. For this reason, the servo control valve 13 is provided with a pump load pressure P acting on one end (13a).
a and the resultant force of the spring 13c and the force acting on the other end (13b), the servo control valve 1
The spool 3 (not shown) is moved to the left. The servo control valve 13 is opened by an amount corresponding to the amount of movement, and the control pressure is transmitted to the servo piston 12, and the swash plate angle of the pump 11 is controlled to determine the discharge volume q (cc / rev).

The pressing member 19 connected by the movement of the servo piston 12 moves. Springs 14c, 14
When the pressing member 19 abutting on d moves, the TV
Springs 14c and 14 for pressing a piston (not shown) of the C valve 14.
The spring force of d is variable. One end of the TVC valve 14 is supplied with a pump load pressure Pa from the pump 11 through a conduit 21e.
Through the operation section 14a of the TVC valve 14.
Further, a variable spring force generated by the springs 14c and 14d acts on the other end side. The piston (not shown) of the TVC valve 14 is located at a position where the variable spring force generated by the springs 14c and 14d and the force by the pump load pressure Pa are balanced, that is, between the positions 14e and 14f, and the conduit 21f
And the conduit 23 are connected via a piston (not shown). At this time, when the control pressure from the pump 11 to the pressure chamber 12b is large due to the pump load pressure Pa, the pipe 21f, the TVC valve 14, the pipe 23, the servo control valve 13, the servo response switching valve 62, and the pipe 22 When the force due to the pump load pressure Pa is small, the return oil from the pressure chamber 12b is supplied to the conduit 2b.
2. Servo response switching valve 62, servo control valve 13, conduit 2
3, connected to the tank 29 via the TVC valve 14 and the conduit 28. Thereby, when the force due to the pump load pressure Pa increases, the servo piston 12 moves in the direction in which the discharge amount of the pump 11 decreases, and the pump load pressure P
When the force due to a decreases, the servo piston 12 moves in a direction in which the discharge amount increases.

Further, in the above, the TVC valve 14 receives a command from the control device 100 to the solenoid operating portion 14b provided at one end together with the force due to the pump load pressure Pa, and increases and decreases the force of the solenoid. 11 can be increased or decreased. From the above, the pressure chamber 12a
Is also controlled by the pump load pressure Pa, the springs 14c and 14d of the TVC valve 14, and the solenoid operating unit 14b. Thus, the discharge volume q (cc / rev) of the pump 11 is controlled by the servo control valve 13 and the TVC valve 14. Therefore, when the rotation speed n of the pump 11 is determined, the discharge capacity Q (l / min) of the pump 11
Is determined by the product of the discharge volume q (cc / rev) and the rotation speed n of the pump 11, as is well known. Spring 14c, 1
By setting 4d to a predetermined value, the product of the discharge pressure and the discharge capacity of the pump 11 can be made substantially constant horsepower (for example, FIG. 6).
(Dotted line Hsl). At this time, the driving horsepower H of the pump 11 becomes the pump load pressure Pa (Kg /
cm ² ) and the discharge capacity Q (l / min) (drive horsepower H = k · Pa · Q = k · Pa · q · N, where k is a constant and N is the rotation speed of the pump). . Also,
At this time, the driving torque T of the pump 11 is determined by the pump load pressure Pa (Kg / cm ² ) and the discharge volume q (cc / rev).
(Drive torque T = k · Pa · q, where k is a constant).

Next, the operation of the first embodiment when the active mode Aw is selected by the work mode setting switch section 91 of the present invention will be described. In the working state of the active mode Aw, as shown in Table 1, the control device 100 outputs a command to each unit.

[0054]

[Table 1]

Control device 100 in active mode Aw
From the active mode switching unit 60. For example, a command is output to the directional control valve electromagnetic switching valve 64 to increase the maximum stroke S of the directional control valve 41, and the two-stage relief valve 44, the two-stage safety valve 45 with a suction valve, and the two-stage safety valve 46 Send pilot hydraulic pressure to increase pressure. Further, the cut-off function release control is performed without outputting a command to the solenoid operating portion 14b of the TVC valve 14, and the servo response electromagnetic valve 63 is controlled so as to speed up the servo response without outputting the command. Further, the horsepower control of the pump 11 is performed with high control without outputting a command to the electromagnetic switching valve 61 for output torque. It should be noted that the command to each electromagnetic switching valve and ON / OFF may be set in reverse according to the circuit configuration without being restricted by Table 1. Also, it goes without saying that the electromagnetic switching valve 64 for the direction control valve, the electromagnetic valve 63 for the servo response, and the electromagnetic switching valve 61 for the output torque can be integrated into one by the circuit configuration.

In the above circuit configuration, the matching point between the engine output torque in the active mode Aw and the absorption torque of the pump is higher than the point (Ts) in the standard mode Sw, as shown in FIG. Output torque point (Ta) at the time, and the rotation speed is set to the standard mode Sw.
From Ns at the time to Na at the active mode Aw. Thereby, as shown in FIG. 6, the discharge amount of the pump is changed from Qsl in the standard mode Sw to the active mode A.
It has increased to Qah at w hours. Active mode A
The solid line (Hah) of the constant horsepower control of the w pump is set higher than the broken line (Hsl) of the constant horsepower control of the pump in the standard mode Sw. This is because the output torque electromagnetic switching valve 61 is switched to the port position 61b in the standard mode Sw in the discharge capacity Qsl of the pump 11 in the standard mode Sw.
This is because the operation unit 13aa is connected to the tank 29 to reduce the pressure, and the discharge amount of the pump 11 is increased to the Qah point.

Hereinafter, the operation of the active mode Aw and the standard mode Sw will be described. An example of a hydraulic circuit of a hydraulic shovel in a construction machine will be described. (1) The matching control between the output torque of the engine 1 and the output torque of the pump 11 will be described. The active mode Aw will be described. When the operator selects the active mode Aw, as shown in FIG. 5, the rotation speed of the engine 1 rotates at the maximum no-load rotation speed (for example, N0). When the operator operates the operation lever to increase the actuator pressure Pb and / or increase the discharge amount Q of the pump 11, the servo control valve 13 and the TVC valve 14 are controlled as described above to
, The absorption torque of the pump 11 increases. When the pump 11 increases the absorption torque, the rotation speed of the engine 1 becomes the no-load maximum rotation speed N according to the increase.
Decreasing from 0. Further, the actuator pressure P
b, and / or when the discharge amount Q of the pump 11 increases and decreases to the rotation speed Na of the engine 1, the engine output torque and the absorption torque of the pump become the matching point (T
Match in a). In the active mode Aw, this point is set to the rated output torque point of the engine 1 (for example, the rotation speed Na). Next, the actuator pressure Pb and / or the discharge amount Q of the pump 11 are further determined.
Increases and the absorption torque of the pump 11 exceeds the output torque TaA of the engine 1, conventionally, the pump 11
Of the engine 1 decreases along the dashed line (a)
To avoid a decrease in rotation speed.

On the other hand, in the present invention, the actuator pressure Pb and / or the discharge amount Q of the pump 11
Is increased and the absorption torque of the pump 11 exceeds the output torque TaA of the engine 1, the discharge amount Q of the pump 11 is not reduced. That is, the discharge amount Q of the pump 11 remains unchanged, or the discharge volume q of the pump 11 is increased. For this purpose, the control device 100 reduces the command output to the solenoid portion 14b of the TVC valve 14 to reduce the port position 14e.
To Thereby, the pressure chamber 12 of the servo piston 12
The return oil from a is supplied to the conduit 22, the servo response switching valve 62,
Port position 13b of servo control valve 13, conduit 23, TV
It is connected to a tank 29 via a port position 14 e of the C valve 14 and a conduit 28. Therefore, the servo piston 1
2 moves rightward in the figure where the discharge amount increases, and moves the pressing member 19 connected to the spring 14.
Change the spring force of c and 14d. The piston (not shown) of the TVC valve 14 has a variable spring force generated by the springs 14 c and 14 d, a force due to the pump load pressure Pa, and the TVC valve 14.
At a position where the resultant force is balanced with the force of the solenoid portion 14b of the servo piston 12 from the pressure chamber 12a of the servo piston 12.
The flow of the return oil to is stopped, and the movement of the servo piston 12 is stopped. Accordingly, the discharge volume q of the pump 11 becomes a value of the discharge volume increased according to the command value from the control device 100 to the TVC valve 14.

By repeating this, the discharge volume q of the pump 11, that is, the discharge amount Q of the pump 11 is increased according to the rotation speed of the engine 1. As a result, the load torque of the pump 11 to the engine 1 remains unchanged or increases, and the rotation speed of the engine 1 decreases while changing its tone. Due to this increase in the load, the matching point between the engine output torque and the pump absorption torque moves to the higher torque side on the engine output torque line (b). When a skilled operator operates the operation lever to slightly reduce the load, the load decreases and the engine output torque line returns to the rated torque point. At this time, a skilled operator determines the tone of the engine 1 and restores the rotation speed of the engine 1 as appropriate. Also, the matching point Ta moves on the engine output torque line (b) to the high torque side,
La is set so that the engine output torque continues with a predetermined width.

Thus, when the load is continuous, the engine 1 outputs at the width end on the high torque side. Furthermore, when the load increases due to excavation work or the like, a skilled operator returns the operation lever to the neutral direction, reduces the discharge amount Q of the pump 11, and avoids stopping the engine 1. As a result, the load of the pump 11 sufficiently acts on the engine 1, and the discharge rate of the pump 11 is not reduced, so that the work speed can be prevented from being reduced. .

In the above description, the matching control between the output torque of the engine 1 and the absorption torque of the pump 11 can be performed as shown in FIGS. 7, 8, and 9. 7, 8, and 9 all show the rotational speed (N) of the engine on the horizontal axis,
The vertical axis indicates the output torque (T) of the engine and the absorption torque of the pump, and the output torque of the engine 1 is indicated by a two-dot chain line (a). The absorption torque of the pump 11 is indicated by a solid line (A), a broken line (B), and a dashed line (C).

In FIG. 7, a solid line A, a dotted line B, and a dashed line C indicating the absorption torque of the pump 11
This shows that the discharge volume q of 1 is kept constant without being changed. Changes in Ma, Nb, and Rc at the matching point between the output torque of the engine 1 and the absorption torque of the pump 11 are as follows:
It changes depending on the load pressure applied to the pump 11. The control based on only the hydraulic pressure in FIG.

In FIG. 8, a solid line D, a dotted line E, and a dashed line F indicating the absorption torque of the pump 11
1 shows that the discharge volume q of one is changed. Engine 1
Of the matching point between the output torque of the pump 11 and the absorption torque of the pump 11 are represented by the discharge volume q of the pump 11
It changes by changing. The pump 1 of FIG.
The control for changing the discharge volume q of 1 is called pattern B.

In FIG. 9, the solid line G, the dotted line H, and the dashed line J indicating the absorption torque of the pump 11
This shows that the discharge volume q is also changed so that the absorption torque becomes constant in accordance with the load pressure applied to No. 1. Changes in Mg, Nh, and Rj at the matching point between the output torque of the engine 1 and the absorption torque of the pump 11 change by changing the discharge volume q of the pump 11 in accordance with the load pressure. The control for changing the hydraulic pressure and the discharge volume q of the pump 11 in FIG.

Next, the control of matching between the output torque of the engine 1 and the absorption torque of the pump 11 in the embodiment of the present invention will be described. In FIG. 10, when the load pressure of the pump 11 increases, FIG. Control is performed to indicate when the pressure drops. FIG. 12 shows another embodiment in which the load pressure decreases. In FIG. 10, in step 1, it is determined whether the load pressure of the pump 11 is equal to or less than a predetermined pressure (Pa ≦ 250 kg / cm ² ). In the case of being equal to or below, the control of the pattern A is performed in step 2.
In the above case (Pb> 250 kg / cm ² ), in Step 3, the load pressure of the pump 11 is continuously 0.5 second or more,
Alternatively, it is determined whether they are equal. If not,
Repeat step 3. If it is 0.5 seconds or more, or if it is equal, it is determined in step 4 whether the load pressure of the pump 11 is equal to or less than a predetermined pressure (Pc ≦ 300 Kg / cm ² ). In the case of equality or the following, the control of the pattern A to the pattern B is performed in step 5. Modulation 1.0
Perform in seconds. If not (Pb> 300 kg / cm ² ), in step 6, control of pattern A to pattern B is first performed in 1.0 second of modulation. Next, the control of the pattern B to the pattern C is continuously performed in 0.5 seconds of the modulation. This control is performed up to the set pressure of the two-stage relief valve 44 (Pd = 325 Kg / cm ² ).

When the pressure is to be decreased, in FIG. 11, it is determined in step 11 whether the load pressure of the pump 11 is equal to or less than a predetermined pressure (Pe ≦ 300 kg / cm ² ). . No (Pb> 300
Kg / cm ² ), the pattern C is controlled in step 12. In the case of being equal to or less than, in step 13, the load pressure of the pump 11 is increased to a predetermined pressure (Pf ≦
250Kg / cm ² )
Is determined. If not, the control of the pattern C from the pattern C is performed in step 14 by the modulation 0.1.
Perform in seconds. In the case of equality or less, in step 15, control of pattern C to pattern B is performed first with a modulation of 0.1 second. Next, the control of the pattern A from the pattern B is continuously performed with the modulation 0.
Perform in 2 seconds.

Next, in another embodiment in which the pressure is decreased, hysteresis is provided on the pressure increasing side and the pressure decreasing side.
In FIG. 12, it is determined in step 21 whether the load pressure of the pump 11 is equal to or less than a predetermined pressure (Pg ≦ 280 Kg / cm ² ). No (P
If b> 280 Kg / cm ² ), the pattern C is controlled in step 22. If it is equal to or less than, it is determined in step 23 whether the load pressure of the pump 11 is equal to or less than a predetermined pressure (Ph ≦ 230 Kg / cm ² ). If not, in step 24, control from pattern C to pattern B is performed with a modulation of 0.1 second. If equal or less, then in step 25, control of pattern C to pattern B is first performed with a modulation of 0.1 second. Next, control from pattern B to pattern A is performed continuously with a modulation of 0.1 second.

In the above embodiment, the modulation of the rate of change of the TVC 14 has a difference between the pressure increasing side and the pressure decreasing side. As a result, the engine 1 is made more sticky by adopting a slow modulation on the rising side,
On the descending side, rapid modulation of the engine 1 is obtained by rapid modulation.

Next, another example of the control method is shown in FIG.
The flowchart will be described with reference to FIG. In step 31, the control device 100 determines whether or not the active mode Aw is selected by the work mode setting switch unit 91 (NO). If no, step 31 is repeated. If it is selected (YES), the measurements in steps 32 and 33 are performed. In this case, in step 32, the load pressure of the pump 11 is measured, and in step 33, the discharge volume q of the pump 11 is measured by the tilt angle sensor 101 and sent to the control device 100.

In step 34, the absorption torque T of the pump 11 is determined based on the measurement results in steps 32 and 33.
p (Tp = k · Pa · q, where k is a constant) is calculated. In step 35, the pump 1 obtained in step 34
It is determined whether or not the first absorption torque Tp has exceeded the rated output torque point of the engine 1. At this time, the rated output torque point of the engine 1 is set at the time of design, and the control device 10
0 is stored in a storage unit (R0M) (not shown). N
In the case of O, the process returns to step 32. If YES, go to step 36. In step 36, the rotational speed of the engine 1 is measured.

In step 37, the control device 100 outputs a command to the solenoid 14b of the TVC 14 so that the absorption torque of the pump 11 becomes the output torque at the time of the rotation speed of the engine 1. At this time, the storage unit of the control device 100 stores the engine 1 that changes according to the rotation speed of the engine 1.
Is stored. The storage unit (R0
M) stores the correlation between the output torque of the engine 1 and the absorption torque of the pump 11 that matches the output torque of the engine 1 in order to output a command value to the solenoid 14b of the TVC 14. At this time, TVC14
Is controlled in the same manner as described above.

In step 38, it is determined whether or not a skilled operator operated the operating lever at the rotation speed of the engine 1 selected based on his / her experience when the rotation speed of the engine 1 decreased and the tone changed. are doing. Step 38
In the case of YES at step 39, the discharge volume q of the pump 11 is changed to the discharge volume q corresponding to the operation of the operation lever at step 39. Therefore, the command to the solenoid 14b of the TVC 14 is also reduced accordingly, and the discharge amount of the pump 11 is reduced. Alternatively, since the load is reduced by operating the operation lever and the absorption torque of the pump 11 is also reduced, the load on the engine 1 is reduced, and the rotational speed of the engine 1 is restored to the initial rated rotational speed. If NO in step 38, the process proceeds to step 40, where the decreasing rotation speed is measured.

In step 41, it is determined whether or not the reduced rotation speed of the engine 1 has reached a predetermined rotation speed. If NO in step 41, the process returns to step 38. In the case of YES in step 41, the process proceeds to step 42, and in step 39, the TVC1 is transmitted from the control device.
4 to the solenoid 14b is reduced, and the discharge amount of the pump 11 is reduced. By providing the steps 41 and 42 in the above description, even when the beginner operator selects the active mode Aw, it is possible to avoid the stop of the rotation of the engine 1 even when it is not possible to judge the deterioration of the engine 1 by the tone color.

The case where the standard mode Sw is selected will be described. In FIG. 5, in a state where the engine output torque and the absorption torque of the pump 11 are matched at a matching point (Ts), the actuator pressure Pb is further increased, or the operator increases the operation amount of the operation lever to increase the pump 11. Is required to further increase the discharge volume q of the pump 11, the absorption torque of the pump 11 increases. Therefore, the absorption torque of the pump 11 becomes equal to or more than the output torque of the engine 1, and the rotation speed of the engine 1 decreases. To avoid this, the control device 100 outputs a command to the solenoid 14b of the TVC valve 14 to switch to the port position 14f. Thereby, the servo piston 1 of the pump 11
The second pressure chamber 12a is connected to the pressure chamber 12a of the servo piston 12 via the TVC valve 14, the conduit 23, the servo control valve 13, the servo response switching valve 62, and the conduit 22 from the conduit 21a to the conduit 21b and the conduit 21f. In this case, the discharge amount (dotted line c) of the pump 11 is reduced. As a result, the rotation speed of the engine 1 rotates without decreasing, and in the standard mode, even an operator with a skill close to a beginner can operate easily.

(2) The control of the response speed of the pump 11 will be described. The active mode Aw will be described. When the above-described active mode Aw is selected, the control device 100 does not output a command to the servo response solenoid valve 63, and sets the port position 63a to prevent the pressure of the pilot pump 81 from acting on the servo response switching valve 62. It is shut off. This allows
The servo response switching valve 62 is controlled by the discharge pressure of the pump 11 acting on the operation part 62a at one end between the port 16e of the variable throttle and the port 16f without the throttle. The response time ta of the servo piston 12 is as shown in FIG. It is controlled as shown by the solid line (Awa).

FIG. 14 shows the load pressure of the pump 11 on the horizontal axis and the response time (t) of the servo piston on the vertical axis. In the active mode Aw, the response time ta of the servo piston is, as indicated by the solid line Awa, when the load pressure of the pump 11 is low, the throttle is eliminated to increase the response speed,
When the load pressure of the pump 11 increases sequentially, the response speed of the pump 11 is gradually reduced by the variable throttle. As a result, when the load pressure of the pump 11 is low, the response speed, which is slow due to the sliding resistance of the servo piston 12 and the like, increases, and hunting, which is likely to occur when the load pressure of the pump 11 is high, can be prevented. For example, in a bucket of a hydraulic shovel (not shown), the hydraulic pressure applied to the bucket cylinder from tiltback to excavation is in a range from low pressure to high pressure. Even when the skilled operator operates the bucket quickly, the response speed of the pump at a low pressure is increased, so that the bucket cylinder speed during acceleration is not breathed, and satisfaction is obtained.

The case where the standard mode Sw is selected will be described. When the standard mode Sw is selected, the control device 100 outputs a command to the solenoid valve 63 for servo response to set the port position 63b. As a result, the discharge pressure of the pilot pump 81 acts on the operation unit 16b at the other end,
The servo response switching valve 62 is switched to the fixed throttle port position 62g. Therefore, the response speed of the pump 11 is controlled as shown by a dotted line (Swb) in FIG. In FIG. 14, when the load pressure of the pump 11 is low, the response speed of the pump 11 is slowed.
, The response speed of the pump 11 is gradually increased. This makes the machine easy to handle for beginners who do not want a high speed as before.

(3) The speed switching control of the direction control valve 41 will be described. The active mode Aw will be described. In the direction control valve 41, the spool operation unit 41ba that receives the pilot oil from the operation unit 80 is provided to the operation unit 41b at one end of the spool (not shown) of the boom direction control valve 41d and the arm direction control valve 41e, as described above. The pilot oil from the pilot pump 81 to the electromagnetic switching valve 64 for the directional control valve.
And a spool operation unit 41bb that receives the information via a spool. In the active mode Aw, the pilot pump 8
Since the spool operation unit 41bb receives the pilot oil from No. 1, there is no restriction on the amount of movement of the spool (not shown), and the amount of movement (Sa) of the spool is increased as shown in FIG.

Therefore, when the moving amount S of the spool (not shown) of the direction control valve 41 increases according to the pressure of the pilot oil from the operation section 80, the operation section 1 of the servo control valve 13
The pump load pressure Pa from the discharge line 21 of the pump 11 acting on the pump 3a and the directional control valve 4 acting on the other end 13b
One step lower actuator pressure Pb after throttled by 1
Is smaller. For this reason, the servo control valve 13 moves to the port position 13d, the servo control valve 13 opens by an amount corresponding to the amount of movement, transmits the control pressure to the servo piston 12, increases the swash plate angle of the pump 11, and Eleventh discharge volume q is increased. Thereby, the range in which the difference between the pump load pressure Pa and the actuator pressure Pb occurs, that is,
By increasing the range of the stroke, the range in which the discharge volume q of the pump 11 increases is also increased.

For this reason, the movement amount S of the spool (not shown) of the direction control valve 41 changes according to the pressure of the pilot oil from the operation section 80, and the control oil flowing through the direction control valve 41 according to the movement amount S of the spool. As shown in FIG. 15, the amount is represented by a solid line Awc in the active mode Aw and a standard mode Sw in the active mode Aw.
Changes with the dot-dash line Swd. Active mode Aw
The flow rate to the actuator unit 70 at the time is the standard mode Sw.
The difference between the movement amount of the spool (Sa−Ss) and the flow rate Qsd in the standard mode
It increases to the flow rate Qac at w. Therefore, when the operator selects the active mode Aw, a command is output from the control device 100 to the directional control valve electromagnetic switching valve 64, and the directional control valve electromagnetic switching valve 64 is moved to the port position 64b.
, The pilot oil from the pilot pump 81 is received by the spool operating portion 41bb. Therefore, when the operator greatly operates the operation lever, the pressure of the pilot oil is increased, and the movement amount (Sa) of the spool (not shown) of the direction control valve 41 is increased.
Operation speed can be increased.

The case where the standard mode Sw is selected will be described. In the standard mode Sw, since the spool operation unit 41bb does not receive the pilot oil from the pilot pump 81, the movement amount of the spool (not shown) is restricted. For this reason, as shown in FIG. 15, the movement amount (Ss) of the spool becomes small. Therefore, contrary to the above, the discharge amount of the pump 11 is smaller in the standard mode Sw than in the active mode Aw.

(4) The cutoff control by the TVC valve 41 and the cutoff function release control will be described. The active mode Aw will be described. When the active mode Aw is selected, the control device 100
Without outputting a command to the VC valve 41, the cutoff function release control shown in FIG. FIG. 16 shows the pump pressure (P) on the horizontal axis and the pump discharge amount (Q) on the vertical axis.
A solid line (a) shows an iso-horsepower curve absorbed by the pump 11,
The command current values I0, I0 to the TVC valve 41 are indicated by alternate long and short dash lines.
1,..., I4. This command current value is I0
Is the smallest, and the command current value is gradually increased toward I4. The cutoff function release control is, for example,
The cut-off control (shown by the dotted line Csb in FIG. 16) by the current performed in the standard Sw described later is canceled, and the two-stage safety valve 45 with the suction valve is removed as shown by the thick solid line Caa.
And the pressure set by the set relief pressure (Psd) by the first-stage safety valve of the second-stage safety valve 46 is generated.

Therefore, the cutoff function release control is performed by the operator selecting the active mode Aw, so that the load pressure is the set relief pressure Psd by the first-stage safety valve 45 with the two-stage safety valve 45 with the suction valve and the first-stage safety valve 46. Generates the pressure set by. At this time, the discharge flow rate of the pump 11 is controlled on the solid line (A) of the equal horsepower curve by the load pressure acting on the pump 11.
For this reason, even if the operator performs heavy excavation and the pump load pressure rises to near the set relief pressure Psd,
Since the work of the force at the set relief pressure Psd can be performed without reducing the discharge amount of the pump 11, efficient work can be performed.

The case where the standard mode Sw is selected will be described. When the standard mode Sw is selected, the control device 100 outputs a command to the TVC valve 41 to perform cutoff control by current. The cutoff control is performed by a pressure sensor 90 that detects a pump load pressure of the pump 11.
The controller 100 outputs a command for the current I0 to the solenoid portion 14b of the TVC valve 14 in response to a signal in which the pressure of the pressure No. 1 is a pressure of a predetermined threshold (Psa).
The spool of the valve 14 is pushed into the position toward the port position 14f which is balanced with the springs 14c and 14d. As a result, the pressure chamber 12a of the servo piston 12 of the pump 11 is supplied from the conduit 21a to the conduit 21b and from the conduit 21f to the TVC.
The pressure is transmitted to the pressure chamber 12 a of the servo piston 12 via the valve 14, the conduit 23, the servo control valve 13, the servo response switching valve 62, and the conduit 22, and is set to the discharge amount Qsa of the pump 11.
Further, when the load pressure of the pump 11 rises to the pressure Psb, the control device 100 outputs a command of the current I1 to the solenoid portion 14b, and further pushes a piston (not shown). As a result, a high pressure enters the pressure chamber 12a of the servo piston 12 and moves the servo piston 12. Therefore, the discharge amount of the pump 11 is reduced from the discharge amount Qsa to Qsb.

Further, when the pump load pressure sequentially increases and then increases to the pressure Psd, the control device 100 outputs a command of the current I4 to the solenoid portion 14b to reduce the discharge amount of the pump 11 to the minimum discharge amount Qsd. qmin. When the discharge amount of the pump 11 becomes the minimum discharge amount Qsd, it becomes the first-stage set relief pressure Psd of the two-stage relief valve 44, and the minimum discharge amount Qsd of the pump 11 returns to the tank 29 from the two-stage relief valve 44. By performing such control, a dotted line Csb for cutoff control, for example, shown in FIG. 16 is obtained. For this reason, the operator performs heavy excavation, and the pump load pressure becomes the set relief pressure Psd.
The cut-off control is performed when the pressure becomes zero, and the discharge amount Q of the pump 11 decreases, so that even if a novice operator works for a long time at the set relief pressure, the temperature does not become high and energy consumption is reduced. it can. In the above description, the command current value output to the TVC valve 14 is a comparison between the current value Tt obtained from the torque control and the current value Tc obtained from the cutoff control shown in FIG. I do. By controlling as described above, FIG.
6, the cut-off control shown by the dotted line Csb can be performed without using a dedicated hydraulic cut-off valve as in the related art.
This can be performed by the current to the VC valve 14.

(5) One-touch excavation force increase control for increasing excavation force will be described. Active mode A
w or the one-touch excavation force increase control is selected in either one of the standard mode Sw and the control device 10.
0 outputs a command to the directional control valve electromagnetic switching valve 64, switches to the port position 64b, and changes the pilot oil pressure from the pilot pump 81 to the two-stage relief valve 44, the two-stage safety valve 45 with a suction valve, and the two-stage relief valve. Send to safety valve 46. The one-touch excavation force increase control is selected by a safety valve excavation force increase switch 92 attached to the control device 100. The pilot oil pressure at this time sends a higher pressure than when the first-stage relief pressure is set.
Further, at this time, the control device 100 performs the cutoff function release control by the current without outputting the command to the TVC valve 41.

As a result, in the two-stage relief valve 44, the two-stage safety valve 45 with the suction valve, and the two-stage safety valve 46, the balance piston type relief valve (not shown) and the pilot valve of the safety valve are regulated by the pilot oil pressure as shown in FIG. As shown in (1), the pressure further rises from the first-stage pressure Psd to reach the second-stage pressure Pu. In FIG. 18, the horizontal axis indicates the load pressure (P) of the pump 11, and the vertical axis indicates the pump discharge amount (Q). The pressure at the time of the cut-off function is indicated by a broken line (a).
The pressure when the cutoff function is released is indicated by a dashed line (b), and the pressure when the one-touch excavation force is increased is indicated by a solid line (c). For this reason, the operator performs heavy excavation and the pump load pressure increases to near the set relief pressure Psd,
When the excavation force or the output from the wetland or the like is still insufficient, heavy excavation or escape from the wetland can be performed using the one-touch excavation force increase control.

Next, a description will be given of a second embodiment of the variable displacement pump control device and control method according to the present invention. FIG.
Is a partially enlarged view mainly showing the engine and the pump section corresponding to FIG. 3 of the first embodiment, and FIG. 20 is a partially enlarged view mainly showing the control valve section corresponding to FIG. 4 of the first embodiment. . The same components as those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted. In the first embodiment, in FIGS. 2, 3 and 4, the active mode switching unit 60 includes the output torque electromagnetic switching valve 6.
1, a servo response switching valve 62, a servo response electromagnetic switching valve 63, and a direction control valve electromagnetic switching valve 64. In the second embodiment, in FIGS. 19 and 20, the electromagnetic switching valve 64 for the direction control valve is different, and is constituted by a plurality instead of one. That is, the set pressure of the two-stage relief valve 44 and the two-stage relief valve electromagnetic switching valve 65 for adjusting the set pressure of the two-stage safety valve 45 with suction valve and the two-stage safety valve 46, and the speed of the direction control valve 41. And a directional control valve speed electromagnetic switching valve 66 for controlling switching. The two-stage relief valve electromagnetic switching valve 65 is connected to the control device 100. The directional control valve speed electromagnetic switching valve 66 has a directional control valve speed switch 67.

In the above, when the operator selects the active mode Aw, the control device 100 sets the TVC valve 41
, The cutoff function release control by the current is performed, and the first-stage relief pressure is set. Next, when the operator wants to work at a high speed, the direction control valve speed switch 67 is turned on,
The directional control valve speed electromagnetic switching valve 66 is switched to the port position 66b, and the pilot oil pressure from the pilot pump 81 is sent to the operating portion 41b of the boom directional control valve 41d and the arm directional control valve 41e. As a result, similarly to the first embodiment, there is no restriction on the movement amount of the spool (not shown), and as shown in FIG. 15, the movement amount of the spool (Sa)
Is increased, and the operating speed of the actuator unit 70 is increased. Further, when the operator wants to further increase the excavating force to perform the work, the operator turns on the excavating force up switch 92 for the safety valve, switches the electromagnetic switching valve 65 for the two-stage relief valve to the port position 65b, and sets the pilot position. Pump 81
Is sent to a two-stage relief valve 44, a two-stage safety valve 45 with a suction valve and a two-stage safety valve 46,
Set to high pressure. As a result, similarly to the first embodiment, the pump load pressure increases to near the high set relief pressure Pu shown in FIG. 18, and one-touch operation is performed when the excavation force or the output from the wetland is insufficient. Excavation or escape can be performed using the excavation force increase control.

Next, a description will be given of a third embodiment of the variable displacement pump control device and control method according to the present invention. FIG.
FIG. 3 is an overall configuration diagram of a third embodiment corresponding to FIG. 2 of the first embodiment. The same parts as those in the first embodiment are denoted by the same reference numerals, description thereof will be omitted, and some buckets (73,
41f) The circuit is omitted. In the first embodiment, FIG.
In FIG. 4, proportional pressure solenoid valves 83, 84,... Are used for the operation unit 80 to supply the pilot pressure to the spool operation units 41a, 41b of the respective directional control valves.
In the embodiment, the proportional pressure hydraulic control valves 87, 88, 89,.
Is used. In each proportional pressure hydraulic control valve 87, a proportional pilot pressure is supplied to a spool operating portion 41a, 41b of each direction control valve by a signal of an operation amount of an operation lever (not shown) operated by an operator. As a result, the spool of each directional control valve can obtain a stroke (S) in which the operation amount of the operation lever is proportional to the signal, and a predetermined oil amount according to the operation amount flows through the directional control valve.

In the first embodiment, the active mode switching unit 60 includes an output torque electromagnetic switching valve 61, a servo response switching valve 62, a servo response electromagnetic switching valve 63, and a direction control valve electromagnetic switching valve. In the third embodiment, a solenoid valve 161 for adjusting the set pressure of the two-stage relief valve 44 and a two-stage safety valve with a suction valve are shown in FIG. An electromagnetic switching valve 162 for the safety valve for adjusting the set pressure of the 45 and the two-stage safety valve 46, and an electromagnetic switching valve 66 for the directional control valve speed for controlling the speed switching of the directional control valve 41.
The two-stage relief valve electromagnetic switching valve 161 is connected to the control device 100. The directional control valve speed electromagnetic switching valve 66 has a directional control valve speed switch 67. Further, the safety valve electromagnetic switching valve 162 has a safety valve switch 163.

In the above, when the operator wants to increase the excavating power and perform the work, the control device 100
Without outputting a command to the valve 41, the cutoff function release control by the current is performed, and the second stage relief valve 44 is set to the second highest relief pressure. That is, the electromagnetic switching valve 161 for the two-stage relief valve is switched to the port position 161b, the pilot oil pressure from the pilot pump 81 is sent to the two-stage relief valve 44, and the set pressure of the two-stage relief valve 44 is changed to a two-stage safety valve with a suction valve. 45 and two-stage safety valve 4
Set 6 to high pressure. As a result, the two-stage safety valve 45 with the suction valve and the two-stage safety valve 46 are operated to increase the excavating force to a pressure higher than the normal operation. In addition, when the operator wants to increase the excavating force and perform work, the safety valve switch 1 is used.
Turn on 63, switch to port position 162b,
The pilot hydraulic pressure from the pilot pump 81 is sent to the two-stage safety valve 45 with a suction valve and the two-stage safety valve 46, and a strong force is generated by operating with the set pressure of the two-stage relief valve 44. As described above, it is needless to say that the active mode switching unit 60 can be appropriately controlled without being limited to one. Also, a switch may be provided for the servo response electromagnetic switching valve 63 that makes the response speed of the pump 11 variable.

[0093]

As described above, according to the control apparatus and the control method of the construction machine according to the present invention, the active mode according to the skill of the skilled person and the standard mode according to the skill close to the beginner are set. As a result, a work mode according to the skill can be selected, and a construction machine satisfying the operator can be obtained. In addition, the skilled operator understands that the engine load is reduced while the engine speed is reduced when the work load increases and the load is applied to the pump, and the operator is aware that the engine is overloaded, and is easy to handle. Become a machine. Also, the pressure on the boom head side is set to two stages, high pressure and low pressure.
In the standard mode, low pressure is set, so that beginners can perform heavy excavation according to their skills without lifting the front of the vehicle body due to the reaction force of arm excavation, improving work efficiency. Furthermore, when escaping from a soft ground, by selecting the active mode, even a beginner can increase the thrust of the vehicle body and can easily escape.

The directional control valve has two strokes, a long stroke and a short stroke, and in the active mode, the allowable flow rate is increased. As a result, the satisfaction of the operator is improved, and the deep digging work and the cycle time are shortened to increase the work amount. Also,
The discharge volume of the pump is set in accordance with the response at high pressure, and the throttle is variable, so that the response at high pressure is set at low speed as well as at high pressure. As well as the operator's satisfaction is improved, the cycle time is shortened and the amount of work is increased. Further, since the cut-off valve uses a valve for controlling the torque of the pump, a dedicated cut-off valve can be eliminated and the structure is simplified.

[Brief description of the drawings]

FIG. 1 is an overall block configuration diagram of a variable displacement pump control device according to a first embodiment of the present invention.

FIG. 2 is an overall configuration diagram of a first embodiment of the present invention.

FIG. 3 is a partially enlarged view mainly showing an engine and a pump section of FIG. 2;

FIG. 4 is a partially enlarged view mainly showing a control valve section of FIG. 2;

FIG. 5 is a diagram illustrating matching between the output torque of the engine and the absorption torque of the pump in the active mode Aw according to the present invention.

FIG. 6 is a diagram illustrating the absorption horsepower of the pump in the active mode Aw and the standard mode according to the present invention.

FIG. 7 is a diagram for explaining matching between the absorption torque of the pump and the output torque of the engine when the discharge volume of the pump is constant.

FIG. 8 is a diagram for explaining matching between the absorption torque of the pump and the output torque of the engine when the discharge volume of the pump changes.

FIG. 9 is a diagram illustrating matching between the pump absorption torque and the engine output torque when the load pressure and the pump displacement change and the pump changes at a constant absorption torque.

FIG. 10 is a flowchart illustrating control of matching between the output torque of the engine and the absorption torque of the pump when the load pressure increases.

FIG. 11 is a flowchart illustrating control of matching between the output torque of the engine and the absorption torque of the pump in the case of the first embodiment in which the load pressure decreases.

FIG. 12 is a flowchart illustrating control of matching between the output torque of the engine and the absorption torque of the pump in the case of the second embodiment in which the load pressure decreases.

FIG. 13 is a flowchart illustrating control of matching between the output torque of the engine and the absorption torque of the pump in the case of the third embodiment.

FIG. 14 is a diagram illustrating the response time of the servo piston of the pump in the active mode Aw and the standard mode according to the present invention.

FIG. 15 is a diagram illustrating an allowable flow rate of the directional control valve in the active mode Aw and the standard mode according to the present invention.

FIG. 16 is a diagram illustrating cutoff control by the TVC valve of the present invention.

FIG. 17 is a diagram illustrating a TVC current value when cutoff control is performed by the TVC valve of the present invention.

FIG. 18 is a diagram illustrating one-touch excavation force increase control for increasing excavation force.

FIG. 19 is a partially enlarged view mainly showing an engine and a pump section of FIG. 2 of the second embodiment.

FIG. 20 is a partially enlarged view mainly showing the control valve portion of FIG. 2 of the second embodiment.

FIG. 21 is an overall configuration diagram of a third embodiment of the present invention.

FIG. 22 is an overall configuration diagram of a conventional variable displacement pump control device.

FIG. 23 is a view for explaining matching between the output torque of the engine and the absorption torque of the pump in the heavy excavation mode according to the related art.

FIG. 24 is a view for explaining matching between the output torque of the engine and the absorption torque of the pump in the adjustment mode according to the related art.

FIG. 25 is a diagram for explaining matching between the output torque of the engine and the absorption torque of the pump in the fine operation mode according to the related art.

FIG. 26 is a diagram illustrating a case where the absorption torque of the conventional pump and the output torque of the engine are matched at a rated point.

FIG. 27 is a diagram for explaining matching between equal absorption horsepower of a conventional pump and output torque of an engine.

FIG. 28 is a diagram illustrating a case where a constant absorption torque of a conventional pump and an output torque of an engine are matched.

FIG. 29 is a diagram illustrating a cut-off function according to the related art.

FIG. 30 is a diagram illustrating a cut-off release function according to the related art.

[Explanation of symbols]

1 ... engine 2 ... governor controller 3 ...
Engine rotation sensor, 4 ... fuel injection pump, 5 ... governor, 6 ... governor motor, 7 ... governor position sensor,
8: Throttle amount setting device, 10: Variable displacement pump, 11: Variable displacement pump, 12: Servo piston, 13: Servo control valve, 14: Torque value control valve, 16: Servo response switching valve, 40: Control Valve unit, 41: Direction control valve, 44: Two-stage relief valve, 45: Two-stage safety valve with suction valve, 46: Two-stage safety valve, 60: Active mode switching unit, 61: Solenoid switching valve for output torque, 62: Variable Servo response switching valve for displacement pump, 63 ... electromagnetic switching valve for servo response, 64 ... electromagnetic switching valve for directional control valve, 65 ... electromagnetic switching valve for two-stage relief valve, 66 ... electromagnetic switching valve for directional control valve speed, 67 ... Switch for directional control valve speed, 70 ... Actuator part, 7
1: Boom cylinder, 72: Arm cylinder, 73
... bucket cylinder, 74 ... rotating motor, 80 ... operating section, 81 ... pilot pump, 82 ... relief valve, 83 ... proportional pressure solenoid valve for boom, 84 ... proportional pressure solenoid valve for arm, 85 ... proportional pressure solenoid valve for bucket , 86: Proportional pressure solenoid valve for turning, 87: Proportional pressure hydraulic control valve, 90: Pressure sensor, 91: Work mode setting switch unit, 92: Excavation force up switch for safety valve, 100: Control device, 101: Tilt angle Sensors,
161, an electromagnetic switching valve for a two-stage relief valve; 162, an electromagnetic switching valve for a safety valve; 163, a switch for a safety valve.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI F15B 11/028 F15B 11/02 G 11/16 11/16 Z JP-A-6-280807 (JP, A) JP-A-4-19679 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) E02F 9/20 E02F 9/22 F02D 29/00 F02D 29/04 F15B 11/00 F15B 11/028 F15B 11/16

Claims (4)

(57) [Claims] 1. An engine, a variable displacement pump driven by the engine, pump output control means for controlling a product of a load pressure and a discharge displacement acting on the variable displacement pump to be substantially constant, and a pump. A working device operated by an actuator receiving pressure oil from the working device, and a control device for a construction machine having a selecting device for selecting an output torque of an engine and an absorbing torque of a variable displacement pump according to a work site or work content, A pilot pump that generates pilot pressure oil, servo control means for controlling a swash plate that makes the discharge volume of the variable displacement pump variable, active mode selection / release means for performing powerful work such as heavy excavation, and selection of active mode Control means for outputting a command signal by means of a pilot pump and servo control means by means of the signal. The pilot response of the pump is variable and the pump response speed is low when the load pressure of the pump is low.
When the pump speed is increased and the load pressure of the pump
A control device for a construction machine, comprising: a pump response speed switching means for sequentially decreasing and changing a pump response speed. 2. A control method for a construction machine, wherein an output torque of an engine is selected according to a work site or a work content, and the output torque of the engine is controlled by matching with a load acting on a variable displacement pump to be driven. Set the rated torque point of the engine as the target value by selecting the active mode, move the engine output torque line to the higher torque side by increasing the load, and move the engine output torque line to the rated torque point by decreasing the load. A method for controlling a construction machine, wherein the method is performed for returning. 3. A control method for a construction machine according to claim 2 , wherein a predetermined width is provided on the engine output torque line from the vicinity of the rated torque point to the high torque side, and when a load is continuously output at the width end on the high torque side. . 4. The output torque of the engine is selected according to the work site or the content of the work, and the output torque of the engine is controlled by matching with the load acting on the driven variable displacement pump, and the hydraulic oil from the pump is controlled. In a method for controlling a construction machine having a working machine driven by a plurality of actuators receiving the pressure via a direction control valve, the load pressure of the pump is increased by selecting the active mode.
A method for controlling a construction machine, wherein the response speed of a pump is increased when the speed is low, and the response speed of a work machine is increased.