JPS5926084Y2 - 2-pump hydraulic circuit - Google Patents

Description

[Detailed explanation of the idea] The present invention relates to a two-pump hydraulic circuit.

For example, a known power excavator is equipped with a plurality of hydraulic pumps to independently rotate the boom and raise and raise the arm, and if necessary, both can be performed simultaneously using the combined hydraulic pressure of two pumps. ing.

That is, as shown in the system diagram in FIG.
．． 02 and an arm cylinder 014 driven by oil discharged from a hydraulic pump 01.02, a swing motor 013, travel motors 011 and 012, a packet cylinder 015, and a boom cylinder 016, there are a plurality of operation valves constituting a control valve a. 07.08.09.010゜024
and a plurality of operating valves constituting the control valve 03.
04.05.06.025 are inserted.

For control valve a, operation valves 07°08, 0
9.024 are connected in parallel to each other, but the operation valve 010 is the operation valve 07.08゜09,
024, so when any of the operation valves 07, 08, 09, 024 is operated, no pressure oil flows into the operation valve 010, so no pressure oil flows from the operation valve 010 to the actuator. will no longer be supplied.

On the other hand, in the control valves, each operation valve 03.
04.05.06.025 are connected in parallel to each other.

The arm cylinder 014 is operated by operating valves 03 and 010 which are switched and controlled by the same operating lever, the swing motor 013 is operated by operating valve 05, the travel motors 011 and 012 are operated by operating valves 06 and 07, respectively, and the packet cylinder 015 is controlled by operating valves 06 and 07. 08, the boom cylinder 016 is controlled by operating valves 04 and 09, which are switched and controlled by the same operating lever, respectively.

In this case, operation valves 024 and 025 are not required for normal excavation work, but in order to control an actuator that drives a special work machine, both or one of control valves a and l) are required. This is a relatively expensive investment for general users who only carry out regular excavation work.

With this kind of circuit, during normal excavation work, the excavator machine excavates, and the excavated soil is held by the shovel machine.The power shovel upper rotating body is rotated by the swing motor 013, and the excavator machine is moved to the desired position. During this turning, if there is an obstacle near the excavator, the arm cylinder 014 is driven to retract the excavator to avoid collision with the obstacle. It is.

At that time, the part of the excavator working machine that is driven by the arm cylinder 014 often falls due to its own weight, so the load on the arm cylinder 014 decreases, and therefore the drive oil pressure of the arm cylinder 014 decreases, causing the arm cylinder to drop. 0
Since the pressure in the operating valve 05 that controls the swing motor 013, which is connected in parallel with the operating valve 03 that controls the power excavator 14, decreases, the driving force of the swing motor 013 decreases, causing the upper rotating body of the excavator to speed up. This results in the problem that it takes a long time to turn.

The present invention eliminates these problems of known power excavators by omitting normally unnecessary operating valves, but allows for easy attachment of these if necessary. The purpose of the present invention is to provide a two-pump type hydraulic circuit in which a first and second hydraulic pump, a plurality of parallel operation valves connected in parallel to each other, and a plurality of parallel operation valves connected in tandem with each other. a first control valve including a tandem-operated valve, a second control valve including a plurality of parallel-operated valves connected in parallel to each other, and a tandem-operated valve connected in tandem with the plurality of parallel-operated valves; A control valve, a first actuator controlled by a parallel operation valve in the second control valve, a tandem operation valve in the first control valve, and a tandem operation valve in the second control valve. a second actuator to be controlled; and a plurality of actuators each controlled by a parallel operating valve in the first and second control valves, respectively.
and an additional connection for detachably connecting an operation valve attached to the hydraulic circuit of the second control valve to control the actuator for the special working machine, and a tandem operation in the first control valve. The present invention is characterized in that a switching valve is provided in the first control valve to switch the valve to a parallel operation valve.

One embodiment of the present invention will be explained with reference to the drawings. Figure 2 is a system diagram when no operation valve for controlling special work equipment is added, and Figure 3 is a system diagram when the operation valve for controlling special work equipment is added in Figure 2. This is a system diagram of

In the above figure, 1 and 2 are hydraulic pumps driven by the prime mover 18, respectively; 3. 4. 5. Reference numeral 6 designates operating valves constituting the controller 1 to the roll valve; the operating valve 4 controls the boom cylinder 16; the operating valve 6 controls the travel motor 11;
The operating valve 3 controls the arm cylinder 14, and the operating valve 5 controls the swing motor 13, respectively.

7. 8. Reference numeral 9.10 indicates an operating valve that constitutes the control valve a, in which the operating valve 7 connects the travel motor 12, the operating valve 8 connects the packet cylinder 15, the operating valve 9 connects the boom cylinder 16, and the operating valve 10 connects the arm cylinder 1.
4 respectively.

11 and 12 are operating valve 6 and operating valve 7, respectively.
13 is a swing motor controlled by an operating valve 5; 14 is an arm cylinder controlled by an operating valve 3 and an operating valve 10 controlled by switching the same operating lever; 15 is an operating valve 8; 16 is a boom cylinder controlled by operating valves 4 and 9 which are controlled by switching the same operating lever; 19 is a boom cylinder which detects the operating state of operating valve 5 and operates switching valve 20; By doing so, each operating valve 7, 8 of control valve a. 9.10
High pressure selection valve to switch all to parallel connection, 20
22 is a pilot type switching valve, and 22 is an operation valve that is added to control the actuator 30 that drives the special working machine.It receives hydraulic pressure by being connected between connections A and B of the hydraulic circuit of control valve a. .

Reference numeral 23 denotes an additional operating valve for controlling the actuator 31 that drives the special working machine, and is connected between connections C and D of the hydraulic circuit of the control valve to receive hydraulic pressure.

26.27.28.29 are high pressure selection valves, A, B.
E is a connection for taking out the hydraulic pressure attached to the hydraulic circuit of the control valve a, respectively. When the operation valve 22 for controlling the actuator 30 of the special work machine is not added, as shown in FIG. 2, the connection A,
B communicate with each other, and connection E is closed, and when an operating valve 22 is added, connections A and B are connected to operating valve 2, respectively, as shown in FIG.
2, the connection E also communicates with the discharge oil pipe line of the hydraulic pump 1.

C, D, and F are connections for taking out the hydraulic pressure attached to the hydraulic circuit of the control valve, respectively.If the operation valve 23 for controlling the actuator 31 of the special work machine is not added, as shown in Fig. 2. , connection C9D communicate with each other, and both connection F
is closed, and when the operating valve 23 is added, as shown in FIG. .

T is a tank.

In such a hydraulic circuit, first, in normal excavation work, the actuator 30 for special work equipment and the operation valve 22 are
Since there is no need to add additional connections such as, the hydraulic circuit is as shown in FIG.
Normally, the control valves 5 and 3 are connected in tandem, and the other control valves 4 and 6 are connected in parallel with the control valve 5.

Therefore, when the swing motor 13 is driven by the operating valve 5, the high pressure selection valve 19 inside the control valve A detects the operating state of the operating valve 5 and switches the switching valve 20 via pilot pressure. All operating valves 7, 8. 9. Connect all 10 in parallel.

Therefore, when the swing motor 13 and arm cylinder 14 are operated in conjunction, pressure oil from the hydraulic pump 2 is supplied to the swing motor 13 via the operating valve 5, and pressure oil from the hydraulic pump 1 is supplied to the arm cylinder 14 via the operating valve 10. is,
Even if the drive oil pressure of the arm cylinder 14 decreases, the swing motor 13 is not affected by this decrease in oil pressure, and the upper rotating structure of the power shovel can quickly turn.

Therefore, it is possible to avoid a decrease in the driving force of the swing motor during the operation of retracting the shovel working machine, which occurs in a conventionally known hydraulic circuit.

Next, when performing special work, a special work machine actuator 30, 31 and a special work machine operation valve 22, 23 are added to the hydraulic circuit shown in FIG.
As shown in the figure, when the operation valve 22 and the operation valve 7.8゜9 in the control valve a are always connected in parallel, both the operation valve 23 and the operation valve 5, 6゜4 in the control valve 2 are connected in parallel. and are always connected in parallel.

Therefore, the operation valve 5 or the operation valve 22 or 23 is operated to turn the swing motor 13 or the actuator 3 for special work equipment.
When driving 0.31, high pressure selection valve 19, 26.2
7.28.29 is operating valve 5 or operating valve 22.2
By detecting the operating state of 3 and switching the switching valve 20 using pilot pressure, the operating valve 10 is connected in parallel with the operating valves 7, 8, 9, and 22. Therefore, all operating valves in control valve a are connected in parallel. Therefore, the rotation motor 13 and the arm cylinder 14 operate smoothly and easily without interfering with each other.

Similarly, when the operation valve 23 is operated and the swing motor 13 and arm cylinder 14 are operated in conjunction with each operation valve, pressurized oil from the hydraulic pump 2 passes through the operation valve 5 to the swing motor 13 and is then transferred to the arm cylinder. 14 are supplied with pressure oil from the hydraulic pump 1 via the operating valves 10. Therefore, even when operating the operating valves 22 and 23 at the same time, the switching valve 20 is switched in the same way, and the rotation motor 13 and the arm cylinder are 14 is ensured.

Simultaneous operation of other actuators and actuators 30, 31 controlled by actuating valves 22, 23, respectively, is also possible due to the parallel connection circuit described above.

In the above example, the high pressure selection valve 19.26.27.28
Although the switching valve 20 was switched by dynamically detecting the operating status of the operating valves 5, 22, and 23 at ゜29, the switching valve 20 may be switched mechanically or manually. High pressure selection valve 19, 26.27
．． 28.29 can omit this.

In short, according to the present invention, the first hydraulic pump includes first and second hydraulic pumps, a plurality of parallel operation valves connected in parallel to each other, and a tandem operation valve connected in tandem with the plurality of parallel operation valves. a second control valve including a control valve, a plurality of parallel operation valves connected in parallel to each other, and a tandem operation valve connected in tandem with the plurality of parallel operation valves; a first actuator controlled by the operation valve; a second actuator controlled in conjunction with a tandem operation valve in the first control valve and a tandem operation valve in the second control valve; and a plurality of actuators controlled by parallel operation valves in the second control valve, the operation of controlling the actuators for special work equipment attached to the hydraulic circuits of the first and second control valves, respectively. In addition to providing an additional connection for attaching and detaching valves,
By providing a switching valve in the first control valve that switches the tandem operation valve in the first control valve to a parallel operation valve, it is possible to eliminate operation valves that are necessary for special operations but unnecessary for normal excavation operations. This invention is extremely useful industrially because it eliminates the need to always install it in the control valve, reduces costs, and creates a two-pump hydraulic circuit that ensures interlocking between the swing motor and arm cylinder. be.

[Brief explanation of drawings]

Figure 1 is a system diagram showing the hydraulic circuit of a known power shovel.
Figure 2 shows one embodiment of the present invention, and is a system diagram when no special work machine operation valve is added, and Figure 3 is a system diagram when a special work machine operation valve is added to the system shown in Figure 2. be. 1.2...Hydraulic pump, 3. 4. 5. 6
......operation valve, 7. 8. 9.10...
...Operation valve, 11゜12...Travel motor, 13...Swivel motor, 14...Arm cylinder, 15...Packet cylinder, 16
...Boom cylinder, 18... Prime mover, 19... High pressure selection valve, 20...
Switching valve, 22.23... Operation valve for special work equipment, 26.27.28.29... High pressure selection valve, 30.31... Actuator for special work equipment ,A. B, C, D, E, F... Connection, T... Tank, a, b... Control valve.

Claims (1)

[Claims for Utility Model Registration] The first and second hydraulic pumps 1 and 2, a plurality of parallel operation valves 7.8.9 connected in parallel to each other, and the above-mentioned plurality of parallel operation valves 7.8.9. A first control valve a including a tandem operated valve 10 connected in tandem, and a plurality of parallel operated valves 4, 5 connected in parallel to each other. 6 and the plurality of parallel operating valves 4°5.6 and a tandem operating valve 3 connected in tandem, the second control valve is controlled by the parallel operating valve 5 in the second control valve. a first actuator 13, and a tandem operated valve 10 in the first control valve a.
a second actuator 14 which is controlled in conjunction with the tandem operation valve 3 of the second control valve; and a plurality of actuators controlled by the parallel operation valves of the first and second control valves a and b, respectively. and an actuator for the special working machine, which is provided in the hydraulic circuit of the first and second control valves a and l), respectively.
Additional ports A, B, and C for removably adding operation valves 22 and 23 that control 0 and 31. D, E, F, and a switching valve 20 that detects the state of the parallel operation valve 5 in the second control valve and switches the tandem operation valve 10 in the first control valve a to a parallel operation valve. A two-pump hydraulic circuit featuring the following features: