JPH05332320A - Hydraulic circuit and valve structure for hydraulic working machine - Google Patents

Abstract

PURPOSE:To provide fixed driving force even when the condition of a load acting on an actuator changes at the time of compound action. CONSTITUTION:The hydraulic circuit of a hydraulic working machine has an oil pressure source 2, a directional control valve 21 to lead pressure oil to a turning motor 50, a directional control valve 23 to lead the pressure oil to an arm cylinder 40, check valves 111, 123, F provided on pipe lines branched from center by-pass pipe lines (b), (r), and a variable throttle GI provided on a pipe line 151 to join a pipe line 121 connected to the first input port 51b of a directional control valve 23 to a branched pipe line 122 connected to the second input port 52b of the valve 23. In addition, even when load pressure acting on the arm cylinder 40 is changed by regulating the opening area of the variable throttle GI, a fixed flow rate of pressure oil can be supplied to the turning motor 50. Thus an actuator can function as an operator intends, and moreover working efficiency can be improved in comparison with usual technology.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic circuit and a valve structure of a hydraulic working machine such as a hydraulic excavator, and particularly, when operating a plurality of actuators provided in the hydraulic working machine at the same time, the load on each actuator is large or small. The present invention relates to a hydraulic circuit and a valve structure of a hydraulic working machine that can reliably perform a combined operation regardless of the above.

[0002]

2. Description of the Related Art The prior art of a hydraulic circuit relating to the combined operation of a hydraulic working machine of this type is found in Japanese Patent Publication No. 62-25827. A conventional technique almost equivalent to this known example will be described with reference to FIGS.

FIG. 13 shows an excerpt of a hydraulic circuit for driving an arm cylinder 40 for driving an arm forming a front member of a hydraulic excavator and a swing motor 50 for rotating a swing body. As shown in FIG. 13, the hydraulic circuit according to this conventional technique has a directional control valve 21 for guiding the pressure oil supplied from the hydraulic pressure source 2 to the swing motor 50.
And a direction switching valve 23 leading to the arm cylinder 40. The direction switching valves 21 and 23 are the center bypass passages 110 and 120 that connect the center bypass pipelines b and r with the tank 100 at neutral, and the check valves provided on the pipelines branched from the center bypass pipelines b and r. 111, 12
3, a first input port 51a for taking in pressure oil through F,
51b, the second input ports 52a and 52b, and the tank 1
Tank ports 54a, 54b leading to 00 and an output port 55 leading to the swing motor 50 and the arm cylinder 40.
a, 55b, 57a, 57b. On the other hand, a pipeline connecting the pipeline 121 connected to the first input port 51b of the direction switching valve 23 installed downstream of the hydraulic power source 2 and the branch pipeline 122 connected to the second input port 52b. A fixed diaphragm G0 is provided on the 151.

Further, FIG. 14 shows the above-mentioned directional control valve 23,
The structure of the check valve 123, F and the valve body which integrated fixed throttle G0 is shown. This valve body branches from the center bypass passage 120 connected to the center bypass passage r and the branch passage 122 that branches from the center bypass passage r and connects to the second input port via the integrated check valve F. And a pipe line z branched from the center bypass pipe line b are connected, and a pipe line 121 that leads to the first input port via an integrated check valve 123 is provided. Further, the check valve F and the fixed throttle G0 integrated by the plate member 150 are connected, and an oil passage 151 is formed to connect the check valve 123 and the second input port. The check valves 123 and F are provided with check passages 152 and 153, respectively.

In the conventional hydraulic circuit thus constructed, when the direction switching valve 21 is operated to supply the pressure oil to the swing motor 50, the center bypass input port 53a of the direction switching valve 21 is blocked. The pressure oil passes through the check valve 111 from the first input port 51a or the second input port 52a to the output port 55a, or
57a, and is supplied to the swing motor 50 by the pipe line m or n. Further, the hydraulic oil discharged from the turning motor 50 is supplied to the tank 10 via the tank port 54a.
Set back to 0.

In this state, if the direction switching valve 23 is operated to the side of 23a, the pressure oil flowing out to the branch pipe line z is released.
3, it reaches the second input port 52b via the fixed throttle G0, is guided to the conduit f by the passage 124a and the output port 57b, and is supplied to the oil chamber on the bottom side of the arm cylinder 40. Further, the operating oil discharged from the rod-side oil chamber of the arm cylinder 40 is supplied to the direction switching valve 23 via the pipe line s.
It is returned to the tank 100 by the tank port 54b.

By the way, in a hydraulic excavator, the weight of the arm normally acts in the direction of pushing out the rod. Therefore, when the operation for supplying pressure oil to the bottom side of the arm cylinder 40 (hereinafter referred to as arm cloud) is performed, The bottom pressure of the cylinder 40 becomes low. On the other hand, the turning motor 5
Since the pressure at the start of 0 is high, when the direction switching valve 21 and the direction switching valve 23 are simply connected in series, most of the pressure oil flows to the arm cylinder 40 side with a light load. On the other hand, by providing the fixed throttle G0 as described above, even if the load on the arm is small, the branch conduit z
The internal pressure is maintained at the pressure required for the rotation motor 50 to rotate.

On the contrary, when the direction switching valve 23 is operated to the side of 23b, the center bypass input port 53b and the second bypass
The input port 52b of the
The pressure oil that has flowed out to the first input port 51b via the check valve 123 is guided to the passage 124b, the output port 55b,
The oil is supplied to the rod-side oil chamber of the arm cylinder 40 via the pipe line s. On the other hand, the hydraulic oil discharged from the oil chamber on the bottom side of the arm cylinder 40 is supplied to the conduit f, the output port 57b,
It is returned to the tank 100 via the tank port 54b. As described above, when the pressure oil is supplied to the oil chamber on the rod side of the arm cylinder 40, the pressure loss of the circuit is small because it does not pass through the fixed throttle G0.

Further, in the case of operating the arm alone, no matter whether the direction switching valve 23 is operated to 23a or 23b, the pressure oil from the pipe line r and the branch pipe line z causes the check valve 123,
It is supplied to the first input port 51b or the second input port 52b via F and the fixed aperture G0. At that time, since the pressure in the branch pipe line z and the pressure in the center bypass pipe line r are substantially equal to each other, the flow rate passing through the fixed throttle G0 is small and the pressure loss in the fixed throttle G0 is small.

Therefore, in the hydraulic circuit according to the above-mentioned prior art, when the revolving structure and the arm are operated in combination, in the case of the arm cloud, the pressure in the branch pipe line z is kept high by the fixed throttle G0. The pressure oil can be supplied to the turning motor 50. Also, in other cases,
Since the amount of hydraulic oil flowing through the fixed throttle G0 is small, the pressure loss due to the fixed throttle G0 can be reduced.

[0011]

However, in the above-described hydraulic circuit according to the prior art, since the flow rate characteristic of the fixed throttle G0 is fixed, there are the following problems. That is, for example, in order to expand the working range of the hydraulic excavator, when the arm provided as standard in this hydraulic excavator is replaced with an arm having a longer length, the load applied to the arm cylinder 40 increases and the arm cloud The supply pressure of the conduit f during operation is reduced. Therefore, with the flow rate characteristics of the fixed throttle G0 set according to the standard arm, most of the pressure oil is generated when the arm cloud operation is performed in the combined operation of the swing motor 50 and the arm cylinder 40. It flows to the arm cylinder 40 side, and the predetermined turning force of the turning body cannot be obtained.

If a fixed aperture G0 having a small opening area is used to improve the turning force,
The arm speed at the time of compound operation decreases, and work efficiency deteriorates.

From these facts, in the fixed diaphragm G0 as in the above-mentioned prior art, during the turning and the combined operation of the arms,
It was not possible to set the optimum flow rate characteristics according to the operation amount of each directional control valve.

The present invention has been made in view of the above-mentioned problems of the prior art, and an object thereof is to perform a hydraulic work capable of giving a predetermined driving force to the actuator even when the load condition applied to the actuator changes. To provide a hydraulic circuit and a valve structure of a machine.

[0015]

In order to achieve the above-mentioned object, the present invention provides a hydraulic power source, a plurality of actuators driven by pressure oil supplied from the hydraulic pressure source, and pressure oils to these actuators. A plurality of directional control valves that control the flow, and a positional relationship among the plurality of directional control valves that is upstream with respect to the hydraulic pressure source is a first directional control valve and a second directional control valve that is downstream. At least two directional control valves of the directional control valve branch from a center bypass passage that connects the center bypass pipeline connected to the hydraulic power source with a tank when in the neutral position, and a portion of the center bypass pipeline near the hydraulic source. Input port connected to the first branched pipeline, a second input port connected to the second branched pipeline branched from the center bypass pipeline, and a tank port connected to the tank When And an output port connected to said actuator, said second directional control valve second
A check valve provided on the branch pipe line of the first bypass pipe so as to allow only the inflow from the center bypass pipe line; and the check valve is branched from between the check valve and the second input port. In a hydraulic circuit of a hydraulic working machine, which comprises a flow path control means provided on a pipeline connecting the pipeline and the second branch pipe,
The flow rate control means includes an adjusting means for adjusting flow rate characteristics.

[0016]

Since the hydraulic circuit of the hydraulic working machine according to the present invention is configured as described above, when the first and second directional control valves provided on the upstream side and the downstream side of the hydraulic source are both in the neutral position. The pressure oil supplied from the hydraulic pressure source is guided to the tank via the center bypass passage of the directional control valve.

Further, the first device provided on the upstream side with respect to the hydraulic pressure source
The directional valve of the second position is in the neutral position and is provided on the downstream side.
When the second directional control valve is operated, the second directional control valve is provided with the first branch pipe line branched from the vicinity of the hydraulic source.
While the pressure oil is guided to the input port of, the pressure oil is guided to the second input port via the check valve by the second branch pipe branched from the center bypass pipe. At that time, a flow rate control means is provided on the pipeline connecting the first branch pipeline and the second branch pipeline, and the first input port, and
Most of the pressure oil is supplied to either one of the input ports depending on the connection state between the second input port and the output port.

Further, when the first directional control valve and the second directional control valve are both operated, the center bypass passage of the first directional control valve is blocked, so that the second directional control valve is closed. The pressure oil from the first branch line is supplied to the first input port and the second input port of the direction switching valve.
At that time, when the first input port and the output port are in communication with each other, the flow rate according to the state of the load applied to the actuator is supplied.

On the contrary, the pressure oil supplied to the second input port is supplied through the flow rate control means, and if the second input port and the output port are in communication with each other, this second direction switching is performed. The flow rate controlled according to the load state of the actuator connected to the valve and the setting content adjusted by the adjusting means provided in the flow rate control means is supplied to the actuator.

Therefore, according to the hydraulic circuit of the present invention,
Since the flow of pressure oil to the actuator during the combined operation can be adjusted by the adjusting means provided in the flow rate control means, even if the load condition applied to the actuator changes,
A predetermined driving force can be applied to each actuator.

[0021]

Embodiments of the present invention will be described below with reference to the drawings.

1 and 2 are explanatory views of a first embodiment according to claims 1, 8 and 11 of the present invention. FIG. 1 is a hydraulic circuit diagram according to the first embodiment, and FIG. 2 is a first embodiment. It is a figure which shows the valve structure which incorporated a part of hydraulic circuit by one Example into one valve body. The parts common to the hydraulic circuit and the valve structure according to the prior art shown in FIGS. 13 and 14 are given the same reference numerals.

As shown in FIG. 1, the hydraulic circuit according to the first embodiment includes a first directional control valve 21 for guiding the pressure oil supplied from the hydraulic power source 2 to the swing motor 50, that is, the directional control valve 21. And a second directional control valve that leads to the arm cylinder 40, that is, a directional control valve 23. The directional control valve 21 is located upstream of the hydraulic power source 2, and the directional control valve 2 is
3 is installed on the downstream side. Direction switching valve 2
Reference numerals 1 and 23 denote center bypass passages 110 and 120 that connect the center bypass pipelines b and r at neutral with the tank 100.
And the first input ports 51a, 51b and the second input port 52 for taking in the pressure oil via the check valves 111, 123, F provided on the pipes branched from the center bypass pipes b, r.
a, 52b and a tank port 54 leading to the tank 100
a, 54b, swing motor 50, and arm cylinder 4
Output ports 55a, 55b, 57a, 57b leading to 0
It has and. On the other hand, a pipe 151 connecting the pipe 121 connected to the first input port 51b of the directional control valve 23 and the branch pipe 122 connected to the second input port 52b.
A flow rate control means, for example, a variable aperture G1 is provided on the top. In addition, a pipe line z branched from the center bypass pipe line b
Forms a first branch line, and the line 122 branched from the center bypass line r forms a second branch line.

FIG. 2 shows the structure of the valve body in which the directional valve 23, the check valves 123, F and the variable throttle G1 described above are integrated. This valve body has a center bypass passage 120 connected to the above-mentioned center bypass pipe r and a second input via a check valve F which is a second check valve branched from the center bypass pipe r and integrated. The first branch line 122 that connects to the port and the pressure oil from the branch line z are integrated.
Through the check valve 123, which is a check valve, is provided to the first input port. Furthermore, the check valve F
And a variable throttle G1 integrated by the plate member 150, and an oil passage 151 that connects the check valve 123 and the second input port. Also, the variable aperture G1
Is a needle 160 for adjusting the opening area from the outside,
A lock nut 161 for fixing the needle 160 after the adjustment is provided. The check valves 123, F
The check passages 152 and 153 are provided in each.

In the hydraulic circuit and valve structure according to the first embodiment constructed as described above, first, an arm (not shown),
And the arm cylinder 4 depending on the excavated soil volume of this arm
The needle 160 is operated according to the load pressure of 0 to adjust the opening area of the variable throttle G1. For example, if the arm is replaced with a heavier arm than the standard arm, the arm cloud operation causes the pressure in the conduit f to drop further than that of the standard arm, so the needle 160 is moved downward. , And the aperture area of the variable diaphragm G1 is adjusted to be small. As a result, the pressure in the branch pipe line z is kept high.

The operation of this hydraulic circuit will be described below. When both the directional control valve 21 and the directional control valve 23 are set to the neutral position, the center bypass pipe b is connected to the tank 100 by the center bypass passages 110 and 120.
Therefore, the pressure oil discharged from the hydraulic pressure source 2 is returned to the tank 100.

When the direction switching valve 21 is operated to supply the pressure oil to the swing motor 50, the center bypass input port 53a of the direction switching valve 21 is blocked.
The pressure oil flows through the check valve 111 to the first input port 51a,
Or, from the second input port 52a to the output port 55
a or 57a, and is supplied to the swing motor 50 by the pipe line m or n. Further, the hydraulic oil discharged from the turning motor 50 is returned to the tank 100 via the tank port 54a.

In this state, when the direction switching valve 23 is operated to the side of 23a, that is, when the arm crowd operation is performed,
Since the first input port 51b is blocked, the pressure oil that has flowed out to the branch pipe line z reaches the second input port 52b via the check valve 123 and the variable throttle G1, and the pipe line is formed by the passage 124a and the output port 57b. It is guided to f and supplied to the oil chamber on the bottom side of the arm cylinder 40. Further, the working oil discharged from the rod-side oil chamber of the arm cylinder 40 passes through the pipe line s and the tank port 54b of the direction switching valve 23.
Is returned to the tank 100. At this time, since the opening area of the variable aperture G1 is adjusted as described above, a predetermined amount of pressure oil is also supplied to the turning motor 50 side to turn at a predetermined speed.

On the other hand, when the directional control valve 23 is operated to the side of 23b, the second input port 52b is blocked and the conduit 1
21 and the pipeline s communicate with each other through the passage 124b,
The pressure oil from the branch pipe line z is guided to the rod-side oil chamber of the arm cylinder 40 via the first input port 51b.
At that time, since the pressure on the rod side of the arm cylinder 40 becomes high, pressure oil is also supplied to the turning motor 50 side without performing flow rate control.

Further, in the case of operating the arm alone, no matter whether the direction switching valve 23 is operated to 23a or 23b, the pressure oil from the pipe line r and the branch pipe line z causes the check valve 123,
It is supplied to the first input port 51b or the second input port 52b via F and the variable aperture G1. At that time, since the pressure in the branch pipe line z and the pressure in the center bypass pipe line r are substantially equal to each other, the flow rate passing through the variable throttle G1 is small, and the pressure loss in the variable throttle G1 is small.

Therefore, in the hydraulic circuit and the valve structure according to the first embodiment, the opening area of the variable throttle G1 is changed by the needle 160 provided in the variable throttle G1.
Since it can be adjusted according to the arm to be used, even if the condition of the load applied to the arm cylinder 40 changes, a predetermined flow rate of pressure oil can be supplied to the swing motor 50, thereby giving a predetermined swing force. be able to.

3 and 4 are claims 1, 10 and 11 of the present invention.
FIG. 3 is an explanatory view of a second embodiment according to the present invention, FIG. 3 is a hydraulic circuit diagram of the second embodiment, and FIG. 4 is a valve in which a part of the hydraulic circuit according to the second embodiment is incorporated in one valve body. It is a figure which shows a structure.
The parts common to the hydraulic circuit and the valve structure according to the first embodiment shown in FIGS. 1 and 2 are designated by the same reference numerals, and the description thereof will be omitted.

In this second embodiment, the branch pipe z and the branch pipe 122 in the above-mentioned first embodiment are replaced with variable throttles provided on the pipe 151, and the flow rate is changed as shown in FIG. A variable relief valve G2 is provided as control means. Along with this, in order to adjust the relief set pressure,
As shown in FIG. 4, a set screw needle 162 having a spring 164 is provided. In FIG. 4, after the adjustment of the relief set pressure of the variable relief valve G2 is completed, the position of the set screw needle 162 is fixed by the lock nut 163.

In the second embodiment constructed as described above, first, like the first embodiment, first, the set screw needle 1
62 is operated to adjust the set pressure of the variable relief valve G2.
For example, when the set screw needle 162 is moved downward, the spring force of the spring 164 increases and the set pressure of the variable relief valve G2 increases. On the contrary, when the set screw needle 162 is moved upward, the spring force of the spring 164 becomes small and the set pressure of the variable relief valve G2 becomes low.

As shown in FIG. 3, the variable relief valve G2
Operates in accordance with the pressure in the branch pipe line z. Therefore, if the set pressure of the variable relief valve G2 is lowered, for example, the pipe line 1
21 and the branch conduit 122 are in a state of being easily communicated with each other. As a result, during combined operation of turning and arm cloud,
The pressure oil is easily supplied to the oil chamber on the bottom side of the arm cylinder 40, and the operation speed of the arm is improved.

On the contrary, if the set pressure of the variable relief valve G2 is set high, it becomes difficult for the conduit 121 and the branch conduit 122 to communicate with each other, so that the pressure oil is supplied to the turning motor 50 side. Easy, the turning speed is improved.

Therefore, according to this second embodiment,
By adjusting the set pressure of the variable relief valve G2, it is possible to prioritize the turning operation or the excavation work by the arm. That is, it is possible to variably set the driving force of each actuator during the combined operation according to the work content.

FIG. 5 is a diagram showing a hydraulic circuit according to a third embodiment of claims 1 and 9 of the present invention. The parts common to the hydraulic circuit according to the first embodiment shown in FIG. 1 are designated by the same reference numerals, and the description thereof will be omitted.

In the third embodiment, the flow control valve G3 having a pressure compensating function is used in place of the variable throttle provided on the conduit which connects the branch conduit z and the branch conduit 122 in the first embodiment described above. , And a fixed diaphragm 141. The position of the flow control valve G3 is switched by the pressure difference before and after the fixed throttle 141. Also, this flow control valve G
The flow rate characteristic of No. 3 can be variably set by adjusting the spring force of the spring 140.

In the third embodiment thus constructed, first, the spring force of the spring 140 of the flow control valve G3 is adjusted. For example, if the spring force of the spring 140 is increased, the pipeline 1
21 and the branch conduit 122 are easily communicated with each other, and conversely, if weakly set, they are easily disconnected.

Therefore, if the spring force of the spring 140 of the flow rate control valve G3 is set to be strong, pressure oil is easily supplied to the bottom-side oil chamber of the arm cylinder 40 during the combined operation of turning and arm cloud. The operation speed of the arm is improved.

On the contrary, when the spring force of the spring 140 is set to a small value, the pipe 121 and the branch pipe 122 are easily cut off from each other, so that the pressure oil is easily supplied to the turning motor 50 side, and the turning motor 50 is turned. Speed is improved.

Therefore, according to this third embodiment,
Similar to the second embodiment described above, the spring 14 of the flow control valve G3 is used.
By adjusting the spring force of 0, the turning operation can be prioritized or the excavation work by the arm can be prioritized. That is, it is possible to variably set the driving force of each actuator during the combined operation according to the work content.

6 to 8 show the first, second and third aspects of the present invention.
7 and 11 are explanatory views of a fourth embodiment, FIG. 6 is a hydraulic circuit diagram according to the fourth embodiment, and FIG. 7 is a diagram showing a part of the hydraulic circuit according to the fourth embodiment in one valve body. FIG. 8 is a diagram showing the built-in valve structure, and FIG. 8 is a diagram showing the relationship between the pilot operation amount of the directional control valve used in the fourth embodiment and the opening area of the variable throttle. The parts common to the hydraulic circuit diagram and the valve structure according to the first embodiment shown in FIGS. 1 and 2 are designated by the same reference numerals, and the description thereof will be omitted. The position of the directional control valve 21 in the fourth embodiment is switched by the pilot pressure set by the pilot pump 301 and the relief valve 302 according to the operation of the pilot valve 303. The pilot valve 303 is a pressure reducing valve 303 that adjusts the pilot pressure according to the operation amount of the operation lever.
A and 303B are provided. In addition, a variable throttle 300 is provided as a flow rate control unit on the pipeline 151 that connects the pipeline 121 and the branch pipeline 122. This variable aperture 300
Via a shuttle valve 304 and a line 305,
The pilot pressure supplied to the direction switching valve 21 is introduced, and the opening area changes according to this pilot pressure.

As shown in FIG. 7, the plate member 1
The spool 3 is provided with a port connected to the conduit 305, one end of which is supported by a spring 307, and which operates in accordance with the pilot pressure guided by the conduit 305.
06 is installed. By the operation of the spool 306, the pipeline 151 that joins the pipeline 121 and the branch pipeline 122 is formed.
The aperture area of the variable diaphragm 300 changes, and the variable diaphragm 300 is formed.

In the fourth embodiment thus constructed, the supply pressure of the pressure oil supplied to the turning motor 50 rises according to the operation amount of the direction switching valve 21. Along with this, the pilot pressure supplied to the directional control valve 21 increases, so that the variable throttle 300 moves to the right with respect to FIG. 6, and the opening area decreases. The operation amount of the direction switching valve 21 and the variable throttle 300
The relationship with the opening area of is a downward-sloping proportional relationship as shown in FIG. That is, when the operation amount of the turning lever (pilot operation amount) is increased, the opening area of the variable diaphragm 300 is reduced. Therefore, the amount of pressure oil supplied to the arm cylinder 40 when the arm crowd operation is performed during the turning operation depends on the operation amount of the turning lever.

Therefore, according to this fourth embodiment,
When the operation amount of the swing lever is increased, the pressure oil is preferentially supplied to the swing motor 50 side, and the acceleration of the swing structure is improved. On the contrary, when the operation amount is reduced, the pressure oil is preferentially supplied to the arm cylinder 40 side, and the operation speed of the arm is increased. That is, as in the second and third embodiments, it is possible to change the driving force of each actuator during the combined operation according to the work content.

FIG. 9 shows claims 1, 2, 3, 4 of the present invention.
It is explanatory drawing of the 5th Example concerning 7 and 8, and shows the block diagram of this 5th Example. The same parts as those in the fourth embodiment described above are designated by the same reference numerals, and the description thereof will be omitted.

As shown in FIG. 9, the hydraulic circuit in the fifth embodiment has a variable throttle 300 as a flow rate control means.
However, the opening area is changed by the pressure oil guided by the electromagnetic proportional valve 520 as the driving means.
Other than that, the configuration is the same as that of the fourth embodiment.

In the fifth embodiment, the variable throttle 300 provided on the conduit 151 connected to the branch conduit z and an instruction to give priority to the arm operation during the combined operation or the turning operation are designated. Input means 500 and this input means 5
And a calculation means 510 for calculating a supply pressure to the variable throttle 300 based on the input signal and outputting a drive signal corresponding to the calculation result.
Solenoid proportional valve 520 that operates in response to a drive signal from
It has and.

The calculating means 510 has an input section 510a for receiving a signal from the input means 500, a data section 510c for presetting the supply pressure to the variable throttle 300 depending on which of the arm operation and the turning operation is prioritized, and the input section 510a. Part 51
0a, further inputs the signal stored in the data section 510c, calculates the output signal to the solenoid proportional valve 520, and the calculation section 51b.
0b as a signal input to the electromagnetic proportional valve 520 and converted into a drive signal for output. As described in the above-described first to fourth embodiments, in the case where the turning operation is prioritized, the opening area of the variable throttle 300 should be reduced so that the pressure in the branch conduit z is kept high. On the contrary, when the arm operation is prioritized, the aperture area of the variable diaphragm 300 may be increased. Therefore, in the fifth embodiment, as data corresponding to the case where the turning operation is prioritized, the data portion is previously set so that the supply pressure by the solenoid proportional valve 520 is increased in order to reduce the opening area of the variable throttle 300. The high voltage data is stored in 510c.
On the contrary, as the data corresponding to the case where the arm operation is prioritized, the low pressure data is stored in advance in the data 510c so that the supply pressure by the solenoid proportional valve 520 is reduced in order to increase the opening area of the variable throttle 300. Computing unit 510
In b, the high voltage data or the low voltage data stored in the data section 510c is selected according to the signal instructed by the input means 500. For example, the input means 5
When the turning operation priority is instructed by 00, the high voltage data stored in the data section 510c is selected and read.

When the signal from the arithmetic unit 510b is input, the output unit 510d arithmetically outputs a drive signal to the solenoid proportional valve 520 according to the input signal. For example, the calculation unit 5
When high-voltage data (turning operation priority) is output from 10b, a high-current drive signal is output to the drive coil of the solenoid proportional valve 520 so that the supply pressure to the variable throttle 300 becomes high. Conversely, when low voltage data (arm operation priority) is output from the calculation unit 510b, a low current drive signal is output.

When the drive signal from the calculation means 510 is input, the solenoid proportional valve 520 supplies and shuts off the pressure oil to the variable throttle 300 according to the input signal, and the variable throttle 300 is supplied.
Control the opening area of.

Therefore, according to this fifth embodiment,
When the input means 500 gives an instruction to give priority to the arm operation or the turning operation, the pressure in the branch pipe line z can be set to a high pressure or a low pressure according to this instruction. As in the fourth embodiment, the driving force of each actuator during the combined operation can be changed according to the work content.

FIG. 10 and FIG. 11 are claims 1 and 2 of the present invention.
It is explanatory drawing of 6th Example which concerns on 2, 3, 4, 5, 7, 8, FIG. 10 is a block diagram of this 6th Example, FIG. 11 is a turning provided for this 6th Example. FIG. 6 is a diagram showing a relationship between an operation amount of a control lever and an opening area of a variable diaphragm 300. The same parts as those in the above-described fourth and fifth embodiments are designated by the same reference numerals, and the description thereof will be omitted.

In the sixth embodiment, as shown in FIG. 10, a pressure detector 600 for detecting the pilot pressure on the high pressure side introduced by the shuttle valve 304 is provided. Also,
Signal from input means 500 and pressure detector 600
A calculation means 510 for inputting a detection signal from the input terminal, calculating a supply pressure to the variable throttle 300 based on the input signal, and outputting a drive signal corresponding to the calculation result to the solenoid proportional valve 520.
Is equipped with.

The calculation means 510 has an input section 510a for taking in a signal from the input means 500 and a detection signal from the pressure detector 600, a turning operation lever operation amount when the arm operation is prioritized, and an opening area of the variable diaphragm 300. And a data section 510c for presetting the relationship between the operation amount of the operation lever for turning and the opening area of the variable diaphragm 300 when the turning operation is prioritized, and a signal from the input section 510a is input. An arithmetic unit 51 that reads data stored in 510c and calculates an output signal to the solenoid proportional valve 520.
0b and a signal from the calculation unit 510b are input, and an output unit 510 that converts and outputs a drive signal to the solenoid proportional valve 520.
It consists of d and.

As described in the fourth embodiment, the operation amount of the operation lever and the pilot pressure supplied to the directional control valve have a substantially proportional relationship. That is, the pressure detector 60
The pilot pressure detected by 0 corresponds to the operation amount of the operation lever. Therefore, the data section 510c
As shown in FIG. 11, the data corresponding to the case where the arm operation is prioritized is the data whose inclination is gentle with respect to the operation amount of the turning operation lever, and the data corresponding to the case where the turning operation is prioritized. Data having a steep inclination with respect to the operation amount of the turning operation lever is set.

The sixth embodiment is constructed as described above, and since the data is set, the calculating means 51 is used.
At 0, when either the arm operation priority or the turning operation priority is instructed by the input means 500, the pilot pressure from the pressure detector 600 is read, and according to the data stored in the data section 510c, Variable aperture 3
The supply pressure to 00 is calculated, and a drive signal corresponding to the calculation result is output to the solenoid proportional valve 520.

When the drive signal from the calculation means 510 is input, the solenoid proportional valve 520 supplies and shuts off the pressure oil to the variable throttle 300 according to the input signal, and the variable throttle 300 is supplied.
Control the opening area of.

Therefore, according to this sixth embodiment,
When the input means 500 gives an instruction as to which one of the arm operation and the turning operation is prioritized, the pressure in the branch conduit z is set to a pressure corresponding to the instruction signal and the operation amount of the turning operation lever. Therefore, as in the second to fifth embodiments described above, the driving force of each actuator during the combined operation can be made variable according to the work content.

In the above-mentioned first to sixth embodiments, only the combined operation of the arm and the turning is described.
In addition to the arm cloud, if the three operations of the boom lowering operation are combined, the supply of pressure oil to the swing motor also decreases,
The turning acceleration is deteriorated. For this reason, a pressure detector for detecting the operation of the boom, for example, for detecting the pilot pressure of the boom directional control valve is provided, and as shown in FIG. 12, the opening area of the variable throttle with respect to the operation amount of the turning operation lever is changed. The relation may be stored in the data section in the calculating means, and the supply pressure to the variable throttle may be controlled based on the data stored in the pressure detector and the data section.

[0063]

As described above, according to the present invention, since the amount of pressure oil supplied to each actuator can be easily adjusted according to the load applied to the actuator, the condition of the load applied to the actuator changes. However, a predetermined driving force can be applied to each actuator during the combined operation, the operation of the actuator as intended by the operator can be realized, and the work efficiency can be improved as compared with the related art.

Further, in particular, in claims 3 to 10,
The priority order of the operating speed of each actuator in the combined operation can be designated, and each actuator operates at a speed according to this instruction, so that the driving force of each actuator can be made variable according to the work content.

[Brief description of drawings]

FIG. 1 is a hydraulic circuit diagram of a hydraulic working machine according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a valve structure of the hydraulic working machine according to the first embodiment of the present invention.

FIG. 3 is a hydraulic circuit diagram of a hydraulic working machine according to a second embodiment of the present invention.

FIG. 4 is a diagram showing a valve structure of a hydraulic working machine according to a second embodiment of the present invention.

FIG. 5 is a hydraulic circuit diagram of a hydraulic working machine according to a third embodiment of the present invention.

FIG. 6 is a hydraulic circuit diagram of a hydraulic working machine according to a fourth embodiment of the present invention.

FIG. 7 is a diagram showing a valve structure of a hydraulic working machine according to a fourth embodiment of the present invention.

FIG. 8 is a diagram showing a relationship between a pilot operation amount and an opening area of a variable diaphragm in a fourth embodiment of the present invention.

FIG. 9 is a diagram showing a configuration of a main part of a fifth embodiment of the present invention.

FIG. 10 is a diagram showing a configuration of a main part of a sixth embodiment of the present invention.

FIG. 11 is a diagram showing a relationship between an operation amount of a turning operation lever and an opening area of a variable diaphragm in a sixth embodiment of the present invention.

FIG. 12 is a diagram showing a relationship between an operation amount of a turning operation lever and an opening area of a variable diaphragm when a boom is operated in the present invention.

FIG. 13 is a hydraulic circuit diagram of a hydraulic working machine according to the related art.

FIG. 14 is a diagram showing a valve structure of a hydraulic working machine according to a conventional technique.

[Description of Reference Signs] 2 hydraulic power source 21 directional switching valve (first directional switching valve) 23 directional switching valve (second directional switching valve) 40 arm cylinder (actuator) 50 swing motor (actuator) 51a, 51b first Input port 52a, 52b Second input port 54a, 54b Tank port 55a, 55b, 57a, 57b Output port 100 Tank 110, 120 Center bypass passage 122 Branch pipe (second branch pipe) 123 Check valve (first) 1 check valve) 140 spring (adjusting means) 151 conduit 160 needle (adjusting means) 162 set screw needle (adjusting means) 164 spring (adjusting means) 300 variable throttle (flow rate controlling means) 301 pilot pump 303 pilot valve 304 Shuttle valve 305 Pilot line 306 Spool Adjusting means) 307 Spring (adjusting means) 500 Input means 510 Computing means 520 Electromagnetic proportional valve (driving means) 600 Pressure detector (detecting means) b, r Center bypass line F Check valve (second check valve) G1 variable throttle (flow rate control means) G2 variable relief valve G3 flow rate control valve (flow rate control valve having a pressure compensation function) z branch pipe line (first branch pipe line)

Claims (11)

[Claims] 1. A hydraulic pressure source, a plurality of actuators driven by pressure oil supplied from the hydraulic pressure source, and a plurality of directional control valves controlling the flow of pressure oil to these actuators. When at least two directional control valves, which are the first directional control valve and the second directional control valve which are located on the upstream side with respect to the hydraulic pressure source, are in the neutral position. A center bypass passage communicating with a tank and a center bypass passage connected to the hydraulic pressure source, and a first input port connected to a first branch pipeline branched from the vicinity of the hydraulic source of the center bypass pipeline. A second input port connected to a second branch line branched from the center bypass line, a tank port connected to the tank, and an output port connected to the actuator. A check valve provided on the second branch line of the second directional control valve so as to allow only an inflow from the center bypass line, the check valve, and the second input port. In a hydraulic circuit of a hydraulic working machine, which is branched from between, and which includes a flow rate control means provided on a pipeline connecting the first branch pipeline and the second branch pipeline, the flow rate control means: A hydraulic circuit for a hydraulic working machine, comprising an adjusting means for adjusting a flow rate characteristic. 2. The adjusting means determines the state quantity related to the operation of the first directional control valve and the state quantity related to the operation of the second directional control valve according to at least one of the state quantities. The hydraulic circuit for a hydraulic working machine according to claim 1, wherein the hydraulic circuit is an operated unit. 3. A calculation means for calculating an operating force for operating the adjusting means based on the flow rate characteristic of the flow rate control means, and outputting a signal according to the calculation result, and inputting a signal from the calculation means, The hydraulic circuit for a hydraulic working machine according to claim 1, further comprising: a driving unit that outputs a driving signal corresponding to the signal to the adjusting unit. 4. A hydraulic circuit for a hydraulic working machine according to claim 3, further comprising input means for setting a flow rate characteristic of the flow rate control means. 5. A detection means for detecting a state quantity related to the operation of the first directional control valve, and a detection means for detecting a state quantity related to the operation of the second directional control valve. One of the detection means is provided, and the calculation means inputs the detection signal from the detection means, calculates an operation force for operating the adjustment means based on the detection signal and the flow rate characteristic of the flow rate control means, and calculates this The hydraulic circuit of the hydraulic working machine according to claim 3 or 4, wherein a signal according to a result is output. 6. The plurality of actuators and the plurality of directional switching valves are each 3 or more, and the first directional switching valve and the second directional switching valve are excluded.
The detection means detects a state quantity related to the operation of the other directional control valve, and the calculation means inputs the detection signal from the detection means, and based on the detection signal and the flow rate characteristic of the flow rate control means, The hydraulic circuit for a hydraulic working machine according to claim 3 or 4, wherein an operating force for operating the adjusting means is calculated, and a signal corresponding to the calculation result is output. 7. The hydraulic circuit for a hydraulic working machine according to claim 2, wherein the state quantity is a pilot pressure for driving a directional control valve. 8. The hydraulic circuit for a hydraulic working machine according to claim 1, wherein the flow rate control means is a variable throttle. 9. The hydraulic circuit for a hydraulic working machine according to claim 1, wherein the flow rate control means is a flow rate control valve having a pressure compensation function. 10. The hydraulic circuit for a hydraulic working machine according to claim 1, wherein the flow rate control means is a variable relief valve. 11. A center bypass input port and a center bypass output port, which communicate with a tank and a center bypass pipe connected to a hydraulic power source when in a neutral position, and a center bypass output port branched from the vicinity of the hydraulic source of the center bypass pipe. First
Supply port to which the pressure oil is supplied from the branch pipe, the first input port to which the pressure oil supplied through the supply port is guided, and the oil connecting the supply port and the first input port A first check valve provided on the road; and a second input port to which pressure oil is supplied via the center bypass input port when pressure oil is supplied from the hydraulic pressure source to the center bypass pipe line, A second check valve provided on an oil passage connecting the second input port and the center bypass input port;
An oil passage connecting the check valve and the first check valve, a flow rate control means provided on the oil passage, a tank port for guiding the pressure oil guided to each of the input ports to the tank, and an actuator. In a valve structure of a hydraulic working machine including an output port that leads to a flow path, and a spool that switches a connection relationship between each of the input ports and each of the output ports, adjusting means capable of adjusting a flow rate characteristic of the flow rate control means. A valve structure for a hydraulic working machine characterized by being equipped with.