JP2002155904A - Hydraulic control device for construction machinery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To ensure the excellent operability of a hydraulic control device provided with a confluent valve for combining the pressure oil of a third hydraulic pump for supplying the pressure oil to a specifies actuator, to which the pressure oil of a first and a second hydraulic pumps is supplied for junction, and to other actuator by avoiding the influence of the load pressure of the specified actuator in relation to other actuator when operating plural actuators. SOLUTION: The confluent valve 24 is closed by the arm operating pilot pressure, and the pressure oil of the third hydraulic pump 4 is joined with the pressure oil of a first and a second hydraulic pumps 2 and 3 and supplied to an arm cylinder 53. When the turn operating pilot pressure is detected by pilot pressure sensors 66a and 66b and the control signal is output from a controller 65 to a proportional solenoid valve 64, a confluent release valve 62 is operated to cut a line of the arm operating pilot pressure, and releases the confluent function of the confluent valve 24.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic control device provided in a construction machine such as a hydraulic excavator, and more particularly to a specific actuator which can be driven by the joining of hydraulic oil by two hydraulic pumps, and the specific actuator. The present invention relates to a hydraulic control device for a construction machine provided with another actuator different from the above and a third hydraulic pump for supplying pressure oil for driving the other actuator.

[0002]

2. Description of the Related Art As a hydraulic control device for a construction machine, a specific actuator that can be driven by the joining of hydraulic oil by two hydraulic pumps, another actuator different from the specific actuator, and another actuator are driven. There is a so-called three-pump system including a third hydraulic pump that supplies pressurized oil. In such a three-pump system, Japanese Unexamined Patent Application Publication No. 2000-22016
In the hydraulic drive device described in Japanese Patent Application Publication No. 8 (1996), a merge valve is disposed on a center bypass passage connected to the discharge line of the third hydraulic pump and located downstream of the directional control valve for controlling the driving of the other actuator. The pressure oil of the third hydraulic pump is
It can be supplied to a specific actuator by being combined with the pressure oil of the hydraulic pump and the second hydraulic pump.

In the embodiment disclosed in JP-A-2000-220168, the specific actuator is an arm cylinder that drives an arm that is a link element of a front working machine of the hydraulic shovel, and the other actuator is a hydraulic shovel. The joint valve is switched by a control pilot pressure output in accordance with operation of an arm operating device that operates an arm cylinder (specific actuator).

[0004]

However, the above prior art has the following problems.

In the hydraulic drive device described in Japanese Patent Application Laid-Open No. 2000-220168, the pressure oil of the third hydraulic pump merges with the pressure oil of the first hydraulic pump and the second hydraulic pump during the operation of the merging valve, and the specific pressure is increased. Supplied to the actuator. At this time,
The discharge pressure of the third hydraulic pump is higher than the load pressure of a specific actuator. For this reason, when the load pressure of a specific actuator is higher than the load pressure of the other actuators, the pressure of the specific actuator is affected by the load pressure of the specific actuator during the combined operation of both actuators. There is a problem that the oil easily flows in and the driving speed of another actuator is increased in response to a lever input of the same operation device.

For example, when the specific actuator is an arm cylinder and the other actuator is a swing motor as described above, when the merge valve is operated during the half lever operation of the swing operating device, the load pressure of the arm cylinder is swung. The pressure is transmitted to the center bypass passage on the downstream side of the use direction control valve, and the discharge pressure of the third hydraulic pump is instantaneously increased. For this reason, the flow rate of the pressure oil supplied to the swing motor increases, causing unexpected acceleration of the swing motor, which appears in the form of a swing jump, significantly impairing the swing operability and giving an uncomfortable feeling to the operator.

An object of the present invention is to provide a first hydraulic pump and a second hydraulic pump.
In a hydraulic control device having a merging valve for merging and supplying pressure oil of a third hydraulic pump for supplying pressure oil to another actuator to a specific actuator to which pressure oil of a hydraulic pump is merged and supplied, An object of the present invention is to provide a hydraulic control device capable of avoiding the influence of the load pressure of a specific actuator on another actuator during a combined operation with another actuator and obtaining good operability.

[0008]

(1) In order to achieve the above object, the present invention provides a motor, a first hydraulic pump and a second hydraulic pump driven by the motor, and the first hydraulic pump. And a specific actuator that can be driven by the merging of the hydraulic oil discharged from each of the second hydraulic pumps, another actuator different from the specific actuator, and a pressure that is driven by the prime mover and drives the other actuator. A third hydraulic pump that supplies oil, and a joining valve that joins the pressure oil of the third hydraulic pump with the pressure oil of the first hydraulic pump and the second hydraulic pump to selectively supply the specific actuator. A hydraulic control device for a construction machine, comprising: a merging release means for releasing a merging function of the merging valve in response to an operation of the other actuator. To.

As described above, the hydraulic drive device having the first hydraulic pump, the second hydraulic pump, the third hydraulic pump, and the merging valve is provided with the merging releasing means, and the merging function of the merging valve is operated according to the operation of another actuator. By canceling, when the other actuators are not operated, it is possible to further increase the speed of the specific actuator by merging the pressure oils of the first hydraulic pump, the second hydraulic pump, and the third hydraulic pump,
When the other actuator is operated, the merging release means releases the merging function of the merging valve, thereby avoiding the influence of the load pressure of the specific actuator on the other actuator when the specific actuator and the other actuator are combinedly operated, Good operability can be obtained.

(2) In the above (1), preferably,
The merging release means includes a merging release valve that operates in response to the operation of the other actuator and releases the merging function of the merging valve.

Thus, the merging releasing means releases the merging function of the merging valve in response to the operation of another actuator.

(3) In the above (1), preferably, the merging releasing means includes a merging releasing valve for releasing the merging function of the merging valve, and the merging releasing based on a pilot pressure discharged from a pilot pump. A proportional solenoid valve capable of outputting a pilot pressure signal to the valve, a pilot pressure sensor for detecting a pilot pressure signal for operating the other actuator, and operating the proportional solenoid valve in accordance with a signal output from the pilot pressure sensor And a controller capable of outputting a control signal to be controlled.

Thus, the merging releasing means releases the merging function of the merging valve in response to the operation of another actuator.

(4) Further, in the above (1), preferably, the merging releasing means detects a merging releasing valve for releasing the merging function of the merging valve and a pilot pressure signal for operating the other actuator. A pilot pressure sensor,
A controller capable of outputting an electric signal to the merging release valve in response to a signal output from the pilot pressure sensor.

Thus, the merging releasing means releases the merging function of the merging valve in response to the operation of another actuator.

(5) In the above (1), preferably, the specific actuator is an arm cylinder of a hydraulic shovel, and the other actuator is a turning motor of the hydraulic shovel.

Thus, when the swing motor is not operated, it is possible to further increase the speed by the pressure oil of the three main pumps, and to unexpectedly accelerate the swing motor even if the arm cylinder is operated during the swing operation. Can be suppressed, and good turning operability can be obtained.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a hydraulic control device for a construction machine according to the present invention will be described below with reference to the drawings.

FIG. 1 is a diagram showing the overall configuration of a first embodiment of a hydraulic control device for construction machines according to the present invention.

In FIG. 1, a hydraulic control device according to the present embodiment is mounted on a hydraulic shovel, and includes a prime mover (engine) 1, a first hydraulic pump 2, and a second hydraulic pump driven by the prime mover 1. 3. Third hydraulic pump 4
The three main pumps and the pilot pump 5, the valve device 18 connected to the discharge lines 6, 11 of the first and second hydraulic pumps 2, 3, and the valve connected to the discharge line 21 of the third hydraulic pump 4 Device 27. The first hydraulic pump 2 and the second hydraulic pump 3 are of a variable displacement type, and the third hydraulic pump 4 is of a fixed displacement type.

The valve device 18 includes a first valve group including a traveling right direction control valve 7, a bucket direction control valve 8, a boom first direction control valve 9, and an arm second direction control valve 10,
Arm first directional control valve 12, boom second directional control valve 13, spare directional control valve 14, and traveling left directional control valve 1.
5, each of the valves 7 to 10 of the first valve group is connected in the order shown on a center bypass passage 16 connected to the discharge line 6 of the first hydraulic pump 2,
The valves 12 to 15 of the second valve group are connected in the illustrated order on a center bypass passage 17 connected to the discharge line 11 of the second hydraulic pump 3. The discharge lines 6 and 11 of the first and second hydraulic pumps 2 and 3 are provided with a main relief valve (not shown) for defining the maximum discharge pressure of the first and second hydraulic pumps 2 and 3.

Further, in the valve device 18, the center bypass passage 16 is connected to an input port of the first directional control valve 12 for the arm via a merging line 19 on the upstream side of the second directional control valve 10 for the arm. The first directional control valve 12 for the arm is inserted into the merging line 19 from the center bypass passage 16 side.
1st directional control valve 1 for the arm
A check valve 20 for preventing flow from the second side to the center bypass passage 16 is provided.

The valve device 27 has a blade directional control valve 22, a turning directional control valve 23, and a merge valve 24. These valves 22 to 24 are connected to a center bypass passage connected to the discharge line 21 of the third hydraulic pump 4. 25 are connected in the order shown. The discharge line 21 of the third hydraulic pump 4 is provided with a main relief valve 26 that regulates the maximum discharge pressure of the third hydraulic pump 4.

The discharge line 28 of the pilot pump 5 is provided with a pilot relief valve 29 for regulating the discharge pressure of the pilot pump 5.

Directional control valves 7-9, 12-15, 22, 2
Reference numeral 3 denotes an open center type valve as shown in FIG. As shown in FIG. 3, the arm second directional control valve 10 is an open / close valve that is fully opened at the illustrated neutral position. 2nd for arm
When the directional control valve 10 is switched from the illustrated neutral position to the left and right operating positions, the direction control valve 10 shuts off the center bypass passage 16, and the pressure oil from the first hydraulic pump 2, which is supplied to the center bypass passage 16, is passed through the merge line 19. The oil is supplied to the input port of the arm first directional control valve 12, whereby the hydraulic oil from the first and second hydraulic pumps 2 and 3 can be supplied to the arm first directional control valve 12 in a combined manner. I have.

FIG. 4 shows the appearance of a hydraulic shovel equipped with the above hydraulic control device. The hydraulic excavator is mounted on the traveling body 10
0, a revolving body 101, and a front work machine 102. The traveling body 100 travels by driving left and right crawlers 100a, 100b (only one is shown) by left and right traveling motors 50a, 50b (only one is shown). Revolving superstructure 101
Is turned on the traveling body 100 by the turning motor 51. The front working machine 102 includes a boom 103 and an arm 10.
4, a multi-joint structure including a bucket 105, which is rotatably driven in a vertical plane by a boom cylinder 52, an arm cylinder 53, and a bucket cylinder 54, respectively. The bucket 105 is provided with hanging hooks 106, and the load W can be hung on the hanging hooks 106 to perform a hanging operation. A blade 107 is provided at the front of the traveling body 100 and is driven up and down by a blade cylinder (not shown).

The driving of the traveling left motor 50a is controlled by the traveling left direction control valve 15 (see FIG. 1), and the driving of the traveling right motor 50b is controlled by the traveling right direction control valve 7 (the same). The drive is the turning direction control valve 23
The boom cylinder 52 is driven by the boom first directional control valve 9 and the boom second directional control valve 1
3 (the same), the driving of the arm cylinder 53 is controlled by the first directional control valve 12 for the arm and the second directional control valve 10 (the same), and the driving of the bucket cylinder 54 is controlled by the directional control valve 8 for the bucket. (The same),
The driving of the blade cylinder (not shown) is controlled by a blade direction control valve 22 (same).

Returning to FIG. 1, an arm operating device 61 for operating the arm cylinder 53 is provided, and the control pilot pressure output in accordance with the operation of the arm operating device 61 is controlled by pilot pressure lines 60, 60a, The first directional control valve 12 for arm and the second directional control valve 10 for arm are guided through 60b. Further, pilot pressure lines 60c and 60d branch off from pilot pressure line 60, and control pilot pressure is also applied to merge valve 24 via pilot pressure lines 60c and 60d.

The joining valve 24 joins the pressure oil of the third hydraulic pump 4 with the pressure oil of the first hydraulic pump 2 and the second hydraulic pump 3 so as to be selectively supplied to the arm cylinder 53. It has two switching positions: an open position on the right side in the figure and a closed position on the left side in the figure. In addition, the merging valve 24 has a spring 24a at an end on the opening direction operation side and a hydraulic control unit 24b at an end on the closing direction operation side, and a pilot pressure line 60d is connected to the hydraulic control unit 24b. Operation device 61
Is not outputting the operating pilot pressure,
4 is held at a neutral open position on the right side in the figure, which is a neutral position, by a spring 24a, and when the arm operating device 61 outputs an operating pilot pressure and is guided to the hydraulic control unit 24b, the merging valve 24 is closed at the left side in the figure. And the center bypass passage 25 is shut off at a position downstream of the turning direction control valve 23.

FIG. 5 shows the opening characteristics of the merging valve 24. The merging valve 24 does not have metering characteristics, and as shown in FIG. 5, a control pilot pressure smaller than the control pilot pressure SP corresponding to the set force of the spring 24a is given to the hydraulic control unit 24b. Sometimes, the spring 24a is held at the right position in FIG. 1 by the force of the spring 24a and is fully opened. When a control pilot pressure greater than the control pilot pressure SP corresponding to the set force of the spring 24a is applied to the hydraulic control unit 24b, the hydraulic control unit 24b is switched to the left position in FIG. Becomes

The center bypass passage 25 is located between the turning direction control valve 23 and the junction valve 24, and is located between the input port of the first arm direction control valve 12 and the reverse valve 20. It is connected to the portion via a merging line 31, and in the merging line 31 is provided a reverse valve 32 for preventing backflow in the direction of the merging valve 24. For this reason, when the merging valve 24 is switched to the closed position and the center bypass passage 25 is shut off downstream of the turning direction control valve 23 as described above, the pressure oil of the third hydraulic pump 3 flows into the merging line 31, 1
9 and can be supplied to the direction control valve 12 for the arm.

Further, the hydraulic drive device according to the present embodiment transmits a pilot pressure signal to the merging release valve 62 based on the pilot pressure discharged from the pilot pump 5 and the merging release valve 62 for releasing the merging function of the merging valve 24. A pilot solenoid pressure sensor 66a, 66b for detecting a swing pilot pressure for operating the outputable proportional solenoid valve 64 and the swing direction control valve 23.
And a controller 65 capable of outputting a control signal for operating the proportional solenoid valve 64 in accordance with signals output from the pilot pressure sensors 66a and 66b.

The merging release valve 62 applies the control pilot pressure from the arm operating device 61 to the hydraulic controller 24b of the merging valve 24.
And has two switching positions: a merging permission position on the right side in the drawing and a merging release position on the left side in the drawing. In the merging permission position on the right side of the drawing, the merging release valve 62 is connected to the pilot pressure line 60c,
60d, the control pilot pressure can be transmitted to the hydraulic control unit 24b of the merging valve 24. At the merging release position on the left side of the figure, the pilot pressure lines 60c and 60d are shut off, and the control pilot pressure merging valve 24 Hydraulic control unit 24b
To the pilot line 60d
And the hydraulic control unit 24b communicates with the tank.

The merging release valve 62 has a spring 62a at the end on the merging permission direction operating side and a hydraulic control unit 62b at the end on the merging releasing direction operating side, and the hydraulic control unit 62b has a signal line 63. When the proportional solenoid valve 64 is not outputting the pilot pressure signal, the merging release valve 62 is held at the neutral position on the right side in the drawing, which is the neutral position, by the spring 62a. When the proportional solenoid valve 64 outputs the pilot pressure signal, the pilot pressure signal is guided to the hydraulic control unit 62b, and the merging release valve 62 is switched to the merging releasing position on the left side in FIG.
c, 60d are cut off.

FIG. 6 shows the opening characteristics of the merging release valve 62.
In the figure, P1-P2 are pilot pressure lines 60c and 60d.
P2-T is the opening characteristic between the pilot pressure line 60d and the tank. That is, when the pilot pressure signal is not output from the proportional solenoid valve 64, the merging release valve 62 is maintained at the position on the right side in FIG. 1 by the force of the spring 62a, and the space between the pilot pressure lines 60c and 60d is fully opened. . When a pilot pressure signal is output from the proportional solenoid valve 64, the merging release valve 62 is switched to the left position in FIG.
0c and 60d are fully closed, and the pilot pressure line 60
The space between d and the tank is fully open.

FIG. 7 shows the processing function of the controller 65. The controller 65 includes a pilot pressure sensor 66a,
A command current calculating section 69 for generating a current command value SOL based on the signal output from the control current calculating section 66b;
In 9, the current command value SOL is 0 until one of the signals (turning pilot pressure signals) output from the pilot pressure sensors 66a and 66b reaches a predetermined pressure,
When the signal reaches a predetermined pressure, the current command value SOL becomes F
The relationship between the turning pilot pressure signal and the current command value is set so as to be ull. The current command value calculated by the command current calculator 69 is converted into a control signal for the proportional solenoid valve 64 and output.

FIG. 8 shows the input / output characteristics of the proportional solenoid valve 64. The proportional solenoid valve 64 controls the current value of the control signal (current command value).
Is 0, the pilot pressure signal is also 0, and as the current value of the control signal (current command value) increases, the pilot pressure signal increases, and the current value of the control signal (current command value) becomes F.
The input / output characteristics are set so that the pilot pressure signal becomes the maximum Pcmax when ull is reached.

In the first embodiment, for example, the arm cylinder 53 constitutes a specific actuator which can supply the combined pressure oil of the first hydraulic pump 2 and the second hydraulic pump 3. Further, for example, the turning motor 51 constitutes another actuator different from the specific actuator.

Also, a merging release valve 62, a proportional solenoid valve 64,
Controller 65, pilot pressure sensors 66a, 66b
Constitutes a merging release means for releasing the merging function of the merging valve 24 in response to the operation of the turning motor 51 (another actuator).

Next, the operation of the hydraulic control device according to the present embodiment configured as described above will be described.

First, when the arm operating device 61 is operated by a predetermined amount, the first directional control valve 12 and the second directional control valve 10 for the arm are switched, and the pressure oil of the first hydraulic pump 2 and the second hydraulic pump 3 is changed. The two are merged and supplied to the arm cylinder 53.

At this time, when the turning operation device (not shown) is not operated, the pilot pressure sensors 66a, 66
At 6b, the turning pilot pressure is not detected, no control signal is output from the controller 65 to the proportional solenoid valve 64, and the merging release valve 62 is kept at the merging permitted position shown in FIG. Therefore, the operating pilot pressure output from the arm operating device 61 is guided to the hydraulic control unit 24b of the merging valve 24, and the merging valve 24 is switched from the open position on the right side in the drawing to the closed position on the left side in the drawing. As a result, the center bypass passage 25 is shut off downstream of the turning direction control valve 23, and the pressure oil of the third hydraulic pump 3 can be supplied to the arm first direction control valve 12 via the merging lines 31 and 19. The pressure oils of the three main pumps of the first hydraulic pump 2, the second hydraulic pump 3, and the third hydraulic pump 4 are combined and supplied to the arm cylinder 53. As a result, the arm cylinder 53 is driven at a higher speed than when the pressure oils of the two main pumps of the first hydraulic pump 2 and the second hydraulic pump 3 are combined and supplied,
Further increase in the speed of the arm cylinder 53 can be realized.

When a turning operation device (not shown) is operated, a turning pilot pressure is detected by the pilot pressure sensor 66a or 66b, a control signal is output from the controller 65 to the proportional solenoid valve 64, and the merging release valve 62 is turned on. Is switched to the merging release position shown on the left side of the figure. Therefore, the communication between the pilot pressure line 60c and the pilot pressure line 60d is interrupted, the hydraulic control unit 24b of the merging valve 24 communicates with the tank, and the merging valve 24 is kept (or switched) in the open position on the right side in the figure. . As a result, the center bypass passage 25 communicates with the tank,
The pressure oil of the hydraulic pump 3 cannot be supplied to the arm first directional control valve 12 via the merging lines 31 and 19. That is, the merging function of the merging valve 24 is released.

Here, when both the swing operating device and the arm operating device 61 are operated to perform a combined operation of the arm cylinder 53 and the swing motor 51, if the merging valve 24 is switched to the closed position on the left side in the figure, Assuming that the pressure oil of the third hydraulic pump 4 can be supplied to the arm direction control valve 12, if the load pressure of the arm cylinder 53 is higher than the load pressure of the swing motor 51, the load pressure of the arm cylinder 53 As a result, the discharge pressure of the third hydraulic pump 4 also increases accordingly, and the pressure oil flows into the turning motor 51 more easily than when the merge valve 24 is in the open position on the right side in the figure (when the merge valve is not operating). In other words, even if the turning operation device is operated with the same operation amount, the driving speed of the turning motor 51 increases.

For example, the operating device 61 for the arm is operated while the operating device for turning is operated by the half lever, and the merging valve 24 is switched to the closed position on the left side in the figure, so that the center bypass passage 2 is opened.
When the valve 5 is shut off, the load pressure of the arm cylinder 53 is transmitted to the center bypass passage 25 downstream of the turning direction control valve 23 via the merge line 31, and the discharge pressure of the third hydraulic pump 4 increases instantaneously. . For this reason, the flow rate of the pressure oil supplied to the swing motor 51 increases, causing unexpected acceleration of the swing motor 51, which appears in the form of a swing jump,
This significantly impairs the turning operability and gives an uncomfortable feeling to the operator.

In this embodiment, when the turning operation device is operated as described above, the merging function of the merging valve 24 is released, so that the arm operation device 61 is operated during the half lever operation of the turning operation device. Even if operated, the load pressure of the arm cylinder 53 is not transmitted to the center bypass passage 25, and the discharge pressure of the third hydraulic pump 4 does not increase. Therefore, the turning speed does not change, and good turning operability is obtained.

As described above, according to the present embodiment, the first hydraulic pump 2, the second hydraulic pump 3,
The arm cylinder 5
3 can be realized, and the turning motor when the arm cylinder 53 and the turning motor 51 (see FIG. 4) are operated in combination by operating both the turning operation device and the arm operation device 61. Arm cylinder 53 to 51
, The unexpected acceleration of the turning motor 51 can be suppressed even if the arm cylinder 53 is operated during the turning operation, and good turning operability can be obtained.

FIGS. 9 and 1 show a second embodiment of the present invention.
0 will be described. In the drawing, the same components as those shown in FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted. In the present embodiment, a merging valve is provided with metering characteristics.

In FIG. 9, the valve device 27A according to the present embodiment has a merging valve 24A having metering characteristics. The merging valve 24A has three ports of an input port P, an output port C, and a tank port T. A three-port two-position valve having two switching positions, a non-merging position on the right side in the figure and a merging position on the left side in the figure, and the output port C extends in the direction of extension of the arm cylinder 53 via the merging line 31A on the valve device 18A side. Are connected to the actuator line 40. In addition, a spring 24a is provided at the end on the operation side in the non-merging position, and a hydraulic control unit 24b is provided at the end on the operating side in the merging position.

The merging valve 24A connects the input port P and the tank port T at the non-merging position on the right side of the drawing, and cuts off the communication between the input port P and the output port C. At the merging position on the left side of the drawing, the input port The communication between P and the tank port T is cut off, and the input port P and the output port C are connected.

FIG. 10 shows the opening area characteristics of the junction valve 24A. In the figure, PT is the opening area characteristic between the input port P and the tank port T, and PC is the opening area characteristic between the input port P and the output port C. That is, when the operating pilot pressure is not output from the arm operating device 61, the merging valve 24A is maintained at the position on the right side in FIG. 9 by the force of the spring 24a, and the input port P and the tank port T are fully opened. The space between the input port P and the output port C is fully closed. When the operating pilot pressure is output from the arm operating device 61, the stroke moves to the left in the drawing as the operating pilot pressure increases, and the opening area between the input port P and the tank port T decreases as the stroke amount increases. , The opening area between the input port P and the output port C increases. When the operating pilot pressure increases to near the maximum, the merging valve 24A is switched to the position on the left side in the drawing against the force of the spring 24a,
The space between the input port P and the tank port T is fully closed, and the space between the input port P and the output port C is fully open. As described above, the merging valve 24A has a metering characteristic of gradually changing the size of the opening area in accordance with the stroke amount, and when the operating pilot pressure of the arm becomes equal to or larger than a predetermined value, the third hydraulic pump 4 The supply flow rate of the pressure oil to the arm cylinder 53 is increased almost proportionally.

The other structure is the same as the first structure shown in FIG.
This is equivalent to the embodiment.

In the second embodiment constructed as described above, when the turning operation device is not operated, the merging release valve 62 is maintained at the merging permission position on the right side of FIG. 9 as described above. Therefore, the merging valve 24A is connected to the arm operating device 6
1 has an opening area corresponding to the magnitude of the operating pilot pressure output from the third hydraulic pump 4 to the arm cylinder 5.
The flow rate supplied to 3 is a flow rate according to the magnitude of the operation pilot pressure (required flow rate). For this reason, even if the joining point of the pressure oil of the third hydraulic pump 4 is the actuator line 40 downstream of the arm directional control valve 12, the first hydraulic pump 2 and the second hydraulic pump 3 ,
The pressurized oils of the three main pumps of the third hydraulic pump 4 are joined and supplied at a flow rate corresponding to the required flow rate, so that the speed of the arm cylinder 53 can be further increased as in the first embodiment. .

The operation when a turning operation device (not shown) is operated is the same as that of the first embodiment. When the arm cylinder 53 and the turning motor 51 (see FIG. 4) are operated in combination, the operation of the turning motor 51 is controlled. The influence of the load pressure of the arm cylinder 53 is avoided, and in particular, during the turning operation, the arm cylinder 53
Is operated, unexpected acceleration of the turning motor 51 can be suppressed, and good turning operability can be obtained.

Therefore, according to the present embodiment, the same effect as that of the first embodiment can be obtained.

A third embodiment of the present invention will be described with reference to FIGS. In the drawing, the same components as those shown in FIGS. 1 and 9 are denoted by the same reference numerals, and description thereof will be omitted. In the present embodiment, the function of the merging release valve is realized by electronic control.

In FIG. 11, a valve device 27B according to this embodiment is similar to the valve device 27B according to the second embodiment shown in FIG.
It has a merging valve 24A having metering characteristics.
Further, the merging valve 24 of the valve device 27B in the present embodiment
A signal line 63 from the proportional solenoid valve 64 is directly connected to the hydraulic control unit 24b of A, and a pilot pressure signal output from the proportional solenoid valve 64 is given to the hydraulic control unit 24b. That is, in the present embodiment, the proportional solenoid valve 64 constitutes a merging and unlocking valve, the valve device 27B does not include the merging release valve 62 of the embodiment of FIG.
The pilot pressure lines 60c and 60d (FIG. 1) do not branch from zero.

Further, an arm pilot pressure sensor 67 for detecting an operating pilot pressure generated by the arm operating device 61 is provided, and a signal output from the pilot pressure sensors 66a and 66b and the arm pilot pressure sensor 67 are provided to the controller 65B. Is input.

FIG. 12 shows the processing function of the controller 65B. The controller 65B has a first operation unit 70, a second operation unit 71, and a multiplication unit 72. First operation unit 70
The relationship between the current command value SOL that increases as the arm pilot pressure increases and the current command value SOL corresponding to the signal output from the arm pilot pressure sensor 67 is generated. The second calculating unit 71 sets a relationship in which the coefficient K = 1 until any of the turning pilot pressure signals reaches a predetermined pressure, and changes the coefficient to K = 0 when the turning pilot pressure exceeds the predetermined pressure. Then, a corresponding coefficient K is generated in accordance with signals output from pilot pressure sensors 66a and 66b. The multiplier 72 multiplies the current command value SOL output from the first calculator 70 by the coefficient K output from the second calculator 71, and outputs a control signal to the proportional solenoid valve 64.

The other structure is the same as the second structure shown in FIG.
This is the same as that of the embodiment.

In the third embodiment configured as described above, when the arm operating device 61 is operated and the operation pilot pressure is detected by the arm pilot pressure sensor 67, the first operation of the controller 65B is performed. The unit 70 obtains a current command value SOL corresponding to the arm operation pilot pressure signal output from the arm pilot pressure sensor 67,
The current command value SOL is output to the multiplier 72.

At this time, if the turning operation device (not shown) is not operated, the pilot pressure sensors 66a, 66
In 6b, the turning pilot pressure is not detected, and the second computing unit 71 of the controller 65B obtains a coefficient K = 1, and the coefficient K = 1 is output to the multiplying unit 72. The multiplier 72 multiplies the current command value SOL by the coefficient K = 1, and obtains the current command value to be output = SOL. Therefore, in this case, a control signal corresponding to the current command value SOL is output from the controller 65B to the proportional solenoid valve 64, and the proportional solenoid valve 64
Outputs a pilot pressure signal according to the current command value SOL,
The junction valve 24B has its pilot pressure signal (current command value So
The position is switched from the non-merging position on the right side in the figure to the merging position on the left side in the figure according to the size of L). Thereby, the merging valve 2
4A is an opening area corresponding to the magnitude of the operation pilot pressure output from the arm operation device 61, and the flow rate supplied from the third hydraulic pump 4 to the arm cylinder 53 is equal to the magnitude of the operation pilot pressure (required flow rate). The flow rate will be adjusted accordingly.
Therefore, as in the second embodiment, the arm cylinder 5
3 is supplied with pressure oil of three main pumps of a first hydraulic pump 2, a second hydraulic pump 3, and a third hydraulic pump 4 at a flow rate corresponding to a required flow rate, and is the same as in the first embodiment. Further, the speed of the arm cylinder 53 can be further increased.

When a turning operation device (not shown) is operated,
The pilot pressure sensors 66a and 66b detect the turning pilot pressure, and the second calculation unit 71 of the controller 65B determines a coefficient K = 0, and the coefficient K = 0 is multiplied by the coefficient K = 0.
Is output to In the multiplier 72, the current command value SOL is multiplied by the coefficient K = 0, and the current command value to be output is obtained as 0. Therefore, in this case, the control signal is not output from the controller 65B to the proportional solenoid valve 64, and the proportional solenoid valve 64 does not operate. Therefore, no pilot pressure signal is output from the proportional solenoid valve 64, and the merging valve 24A It is kept (or switched) at the non-merging position. This allows
The center bypass passage 25 communicates with the tank, and the pressure oil of the third hydraulic pump 3 cannot be supplied to the arm cylinder 53 via the merge line 31A. That is, the merging function of the merging valve 24B is released. Thereby, the influence of the load pressure of the arm cylinder 53 on the swing motor 51 when the arm cylinder 53 and the swing motor 51 (see FIG. 4) are operated in combination is avoided, and in particular, the arm cylinder 53 is operated during the swing operation. Also, unexpected acceleration of the turning motor 51 can be suppressed, and good turning operability can be obtained.

Therefore, the present embodiment can provide the same effects as those of the first and second embodiments.

A fourth embodiment of the present invention will be described with reference to FIGS. In the drawing, the same components as those shown in FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted. The present embodiment shows another example of the arrangement of the hydraulic control unit of the junction valve.

In FIG. 13, a valve device 27C according to the present embodiment has a merging valve 24C having a metering characteristic, and this merging valve 24C is the same as the merging valve 24B according to the second embodiment shown in FIG. 3 port 2 position valve. The merging valve 27C has a spring 24a at the end on the non-merging position direction operating side and a hydraulic control unit 24b at the end on the merging position direction operating side, and has a hydraulic control unit 24b at the non-merging position direction operating side end. Control unit 24c, and the hydraulic control unit 2
4b is connected to the pilot line 60 of the arm operating device 61 via a pilot pressure line 60e, and the operating pilot pressure from the arm operating device 61 is applied to the hydraulic control unit 24.
b, a signal line 63 from a proportional solenoid valve (merging release valve) 64 is connected to the hydraulic control unit 24c, and a pilot pressure signal output from the proportional solenoid valve 64 is applied to the hydraulic control unit 24c.
Given to.

An arm pilot pressure sensor 67 for detecting an operating pilot pressure generated by the arm operating device 61 is provided on the pilot pressure line 60e.
The controller 65C includes pilot pressure sensors 66a, 6
6b and the signal output from the arm pilot pressure sensor 6
7 is input.

FIG. 14 shows the processing function of the controller 65C. The controller 65C has a first operation unit 70, a second operation unit 74, and a multiplication unit 72. The first operation unit 70 is the same as that of the third embodiment shown in FIG.
The second computing unit 74 sets a relationship in which the coefficient K = 0 until any of the turning pilot pressure signals reaches a predetermined pressure, and changes to a coefficient K = 1 when the turning pilot pressure exceeds the predetermined pressure. And the pilot pressure sensors 66a, 6
A corresponding coefficient K is generated in accordance with the signal output from 6b. The multiplier 72 is also the same as that of the third embodiment shown in FIG. 12, multiplies the current command value SOL by the coefficient K, and outputs a control signal to the proportional solenoid valve 64.

The other structure is the same as the second structure shown in FIG.
This is the same as that of the embodiment.

In the fourth embodiment configured as described above, when the arm operation device 61 is operated, the third operation is performed.
As described in the embodiment, the current command value SOL corresponding to the arm operation pilot pressure signal is obtained by the first arithmetic unit 70 of the controller 65C, and the current command value SOL is output to the multiplier 72.

At this time, if the turning operation device (not shown) is not operated, the pilot pressure sensors 66a, 66
In 6b, the turning pilot pressure is not detected, and the coefficient K = 0 is obtained in the second calculating section 74 of the controller 65C, and this coefficient K = 0 is output to the multiplying section 72. The multiplier 72 multiplies the current command value SOL by the coefficient K = 0 to obtain a current command value to be output = 0. Therefore, in this case, since the control signal is not output from the controller 65C to the proportional solenoid valve 64 and the proportional solenoid valve 64 does not operate, the pilot pressure signal is output from the proportional solenoid valve 64 to the hydraulic control unit 24c of the merging valve 24C. Instead, the merging valve 24C is switched from the non-merging position on the right side in the figure to the merging position on the left side in the figure according to the magnitude of the operating pilot pressure of the arm guided to the hydraulic control unit 24b. Thus, the merging valve 24C has an opening area corresponding to the magnitude of the operating pilot pressure output from the arm operating device 61, and the flow rate supplied from the third hydraulic pump 4 to the arm cylinder 53 is equal to the magnitude of the operating pilot pressure ( (Required flow rate). Therefore, the second
Similarly to the embodiment, the pressure oil of the three main pumps of the first hydraulic pump 2, the second hydraulic pump 3, and the third hydraulic pump 4 is supplied to the arm cylinder 53 in a combined manner at a flow rate corresponding to the required flow rate. , The arm cylinder 53 as in the first embodiment.
Can be further increased.

When a turning operation device (not shown) is operated,
The pilot pressure sensors 66a and 66b detect the turning pilot pressure, and the second calculation unit 74 of the controller 65 obtains a coefficient K = 1, which is output to the multiplication unit 72. In the multiplication unit 72, the current command value SOL and the coefficient K
= 1 and the current command value to be output = SOL is obtained. Therefore, in this case, a control signal corresponding to the current command value SOL is output from the controller 65C to the proportional solenoid valve 64, the proportional solenoid valve 64 outputs a pilot pressure signal corresponding to the current command value SOL, and the merging valve 24C It is kept (or switched) at the non-merging position on the right side in the figure. As a result, the center bypass passage 25 communicates with the tank, and the pressure oil of the third hydraulic pump 4 cannot be supplied to the arm cylinder 53 via the merge line 31A. That is, the merging function of the merging valve 24C is released. Thereby, the influence of the load pressure of the arm cylinder 53 on the swing motor 51 when the arm cylinder 53 and the swing motor 51 (see FIG. 4) are operated in combination is avoided, and in particular, the arm cylinder 53 is operated during the swing operation. Also, unexpected acceleration of the turning motor 51 can be suppressed, and good turning operability can be obtained.

Therefore, the present embodiment can provide the same effects as those of the first and second embodiments.

A fifth embodiment of the present invention will be described with reference to FIG. In the drawing, the same components as those shown in FIGS. 1 and 9 are denoted by the same reference numerals, and description thereof will be omitted. In the present embodiment, the operation method of the merging release valve is an electromagnetic type.

In FIG. 15, the valve device 27D according to the present embodiment has a merging release valve 62D for releasing the merging function of the merging valve 24A having metering characteristics, and this merging release valve 62D is shown in FIG. As in the first embodiment, it has two switching positions, a merging permission position on the right side in the figure and a merging release position on the left side in the figure, and has a spring 62a at the end on the operation side in the merging permission direction. A solenoid control unit 62c is provided at the end on the release direction operation side, and a control signal output from the controller 65 is directly given to the solenoid control unit 62c, and the solenoid control unit 62c is directly operated by the control signal (electric signal). I have. That is, when the controller 65 does not output the control signal, the merging release valve 62D is held in the neutral position on the right side in the drawing, which is the neutral position by the spring 62a, and when the controller 65 outputs the control signal, the merging releasing valve 62D Is switched to the merging release position on the left side in the figure, and the pilot pressure lines 60c, 60d
Cut off.

The other structure is the same as that of the second embodiment shown in FIG.

In the present embodiment thus constructed, when the turning operation device (not shown) is not operated, the merging valve 24A is switched to the merging position and the hydraulic oil of the third hydraulic pump 4 is changed to the first and second hydraulic pressures. It can be combined with the pressure oil of the pumps 2 and 3 and supplied to the arm cylinder 53. When the turning operation device is operated, the joining valve 24A can be kept at the non-joining position and the joining function can be released.

Therefore, according to the present embodiment, the same effect as that of the first embodiment can be obtained.

A sixth embodiment of the present invention will be described with reference to FIG. In the drawing, the same components as those shown in FIGS. 1 and 9 are denoted by the same reference numerals, and description thereof will be omitted. This embodiment shows another example of the merging method on the first and second hydraulic pumps.

In FIG. 16, a valve device 18E according to the present embodiment has a first directional control valve 12 and a second directional control valve 10E as arm directional control valves, and the second directional control valve 10E is connected to the other direction. Like the control valve, it is an open center type valve as shown in FIG. Also, the second directional control valve 1
One of the output ports 0E is connected to the actuator line 40 extending in the direction of extension of the arm cylinder 53 via a merge line 81, and the pressure oil of the first hydraulic pump 2 whose flow rate is controlled by the second directional control valve 10E is merged with the merge line. Via the 81, it joins with the pressure oil of the second hydraulic pump 3 from the first direction control valve 12 and is supplied to the arm cylinder 53.

The other structure is the same as that of the second embodiment shown in FIG.

According to the sixth embodiment configured as described above, the same effect as in the first embodiment can be obtained.

The modification of the sixth embodiment can be similarly applied to the embodiments shown in FIGS. 1, 11, 13 and 15.

As described above, several embodiments of the present invention have been described. However, the above embodiments can be variously modified within the spirit of the present invention. For example, in the above-described embodiment, the arm cylinder 53 constitutes a specific actuator that can supply the combined hydraulic oil of the first hydraulic pump 2 and the second hydraulic pump 3 and can supply the combined hydraulic oil. Is different from other actuators.
However, as long as there is a possibility that the load pressure may be higher than that of the other (other actuator), an exceptional combination may be used. Further, although the third hydraulic pump is of a fixed displacement type, it may be of a variable displacement type similarly to the first and second hydraulic pumps. Further, the valve devices 18 and 27 may be an integrated valve device.

[0085]

According to the present invention, when the other actuator is not operated, the specific hydraulic actuator, the second hydraulic pump, and the third hydraulic pump are joined together to further increase the speed of the specific actuator. In addition to the above, when operating another actuator, the influence of the load pressure of the specific actuator on the other actuator when the specific actuator and the other actuator are combined can be avoided to obtain good operability. Can be.

Further, according to the present invention, it is possible to further increase the speed of the three main pumps by the pressurized oil, and even if the arm cylinder is operated during the turning operation, an unexpected acceleration of the turning motor (ie, (Turning out of turning) can be suppressed, and good turning operability can be obtained.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a hydraulic control device for a construction machine according to a first embodiment of the present invention.

FIG. 2 is a diagram showing details of directional control valves other than the second arm directional control valve provided in the first embodiment shown in FIG. 1 by hydraulic symbols.

FIG. 3 is a diagram showing details of a second arm direction control valve provided in the first embodiment shown in FIG. 1 by hydraulic symbols.

FIG. 4 is a view showing the appearance of a hydraulic shovel as a typical example of a construction machine on which the hydraulic control device of the present invention is mounted.

FIG. 5 is a view showing the opening characteristics of a merge valve provided in the first embodiment shown in FIG. 1;

FIG. 6 is a view showing an opening characteristic of a merging release valve provided in the first embodiment shown in FIG. 1;

FIG. 7 is a functional block diagram showing processing functions of a controller provided in the first embodiment shown in FIG. 1;

FIG. 8 is a diagram showing input / output characteristics of a proportional solenoid valve provided in the first embodiment shown in FIG. 1;

FIG. 9 is a diagram showing a configuration of a hydraulic control device for a construction machine according to a second embodiment of the present invention.

FIG. 10 is a diagram showing an opening area characteristic of a merge valve provided in the first embodiment shown in FIG. 1;

FIG. 11 is a diagram showing a configuration of a hydraulic control device for a construction machine according to a third embodiment of the present invention.

FIG. 12 is a functional block diagram showing processing functions of a controller provided in the third embodiment shown in FIG.

FIG. 13 is a diagram illustrating a configuration of a hydraulic control device for a construction machine according to a fourth embodiment of the present invention.

FIG. 14 is a functional block diagram showing processing functions of a controller provided in the fourth embodiment shown in FIG.

FIG. 15 is a diagram showing a configuration of a hydraulic control device for a construction machine according to a fifth embodiment of the present invention.

FIG. 16 is a diagram illustrating a configuration of a hydraulic control device for a construction machine according to a sixth embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 1 motor 2 first hydraulic pump 3 second hydraulic pump 4 third hydraulic pump 5 pilot pump 6 discharge line 8 directional control valve for bucket 9 first directional control valve for boom 10 second directional control valve for arm 11 discharge line 12 arm 1st directional control valve for boom 13 2nd directional control valve for boom 16 center bypass passage 17 center bypass passage 18 valve device 19 junction line 20 reverse valve 21 discharge line 22 blade directional control valve 23 turning directional control valve 24 junction valve 24a Spring 24b Hydraulic controller 25 Center bypass passage 27 Valve device 28 Discharge line 31 Merging line 32 Reverse valve 50a, 50b Left and right traveling motor 51 Swing motor 52 Boom cylinder 53 Arm cylinder 54 Bucket cylinder 60, 60a to 60e Pilot pressure line 61 Operation for arm Location 62 merging release valve 62a spring 62b hydraulic control unit 63 signal line 64 proportional solenoid valve 65 controller 66a, 66b pivot pilot pressure sensor 100 traveling body 101 swing structure 102 front operating mechanism 103 boom 104 arm 105 bucket

Claims (5)

[Claims] An electric motor, a first hydraulic pump and a second hydraulic pump driven by the electric motor, and drivable by merging of hydraulic oil discharged from each of the first hydraulic pump and the second hydraulic pump. Specific actuators,
Another actuator different from the specific actuator, a third hydraulic pump driven by the prime mover to supply pressure oil for driving the other actuator, and a pressure oil of the third hydraulic pump is supplied to the first hydraulic pump. And the second
A hydraulic control device for a construction machine having a merging valve that can selectively supply to the specific actuator by merging with the pressure oil of a hydraulic pump; A hydraulic control device for a construction machine, comprising a merging canceling means for canceling. 2. The hydraulic control device for a construction machine according to claim 1, wherein said merging release means includes a merging release valve that operates in response to the operation of said another actuator and releases the merging function of said merging valve. A hydraulic control device for a construction machine. 3. The hydraulic control device for a construction machine according to claim 1, wherein said merging release means includes a merging release valve for releasing a merging function of said merging valve, and said merging based on a pilot pressure discharged from a pilot pump. A proportional solenoid valve capable of outputting a pilot pressure signal to a release valve, a pilot pressure sensor for detecting a pilot pressure signal for operating the other actuator, and the proportional solenoid valve according to a signal output from the pilot pressure sensor. A hydraulic control device for a construction machine, comprising: a controller capable of outputting a control signal to be operated. 4. The hydraulic control device for a construction machine according to claim 1, wherein said merging release means detects a merging release valve for releasing a merging function of said merging valve and a pilot pressure signal for operating said another actuator. A hydraulic pressure control device for a construction machine, comprising: a pilot pressure sensor for performing the operation; and a controller capable of outputting an electric signal to the merging release valve in response to a signal output from the pilot pressure sensor. 5. The construction machine hydraulic control device according to claim 1, wherein said specific actuator is an arm cylinder of a hydraulic shovel, and said other actuator is a turning motor of a hydraulic shovel. Hydraulic control device.