JPH02140332A - Working machine oil quantity distribution selecting circuit for hydraulic excavating machine - Google Patents

Abstract

PURPOSE:To improve the operation performance by installing a selector valve into a pilot hydraulic circuit connecting a work operating lever and a main operation valve and changing the confluence form of the discharged oil quantity of a plurality of hydraulic pumps by operating the selector valve. CONSTITUTION:When a mode selecting switch 11, e.g., a boom precedence switch is pressed, selector valves 6 and 9 are operated by the signal electric current supplied from a controller 10. A pilot hydraulic circuit for an arm Hi operating valve and a pilot hydraulic circuit for a turn precedence operating valve are closed, and only a boom circuit is used for the confluence of two pumps. Further, at the arm precedence switch is pressed, selector valves 3 and 9 are operated, and when a turn precedence switch is pressed, selector valves 3 and 6 are operated to close each pilot hydraulic circuit. Further, when a standard switch is pressed, all the selector valves 3, 6, and 9 stop operation.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a hydraulic excavator having an upper revolving body and a lower traveling body, and particularly relates to a hydraulic excavator having a merging circuit of a plurality of hydraulic pumps. Regarding circuits.

[Prior Art] Conventionally, in a hydraulic excavator, when the boom operating lever 1 is operated to the upward side as shown in FIG. It operates to open the circuit, and the pressure oil sent from the two hydraulic pumps 14 and 15 passes through the operation valves and merges to the boom cylinders 16 and 170.
Acts on the bottom side and extends the boom cylinder. When boom raising and arm excavation or arm dumping are operated at the same time, the arm crest operation valve 18 is activated and the amount of oil flowing to the arm operation valve is throttled so that simultaneous operation of the boom and arm can be performed smoothly. .

When the arm operating lever is operated to the excavation side or the dumping side, the arm LO and arm H3 operating valves form a merging circuit in the same way as above, and when the swing operating levers are operated simultaneously, the swing priority operating valve connects to the arm cylinder. The circuit is throttled so that pressure oil is sent preferentially to the swing motor.

[Problem to be solved by the invention] However, when performing work using a hydraulic excavator,
Simultaneous combined operations that combine two or more of the boom, arm, packet, and swing operations are often performed, so depending on the work, the flow rate distribution of hydraulic fluid to the work equipment may be inappropriate. Therefore, a phenomenon has occurred in which the two-pump merging circuit is not necessarily effective.

For example, when excavating soil in a trench excavation work in a direction of 45 degrees to the center line of the trench, once one excavation is completed, the boom must be raised, the arm dumped, and swiveled simultaneously in order to move the packet to the dumping point. However, at this time, the two valves for rotation and rotation priority are activated for the rotation operation, and the oil ↑ to the arm Lo operation valve is controlled to supply pressure oil preferentially to the rotation circuit.

In addition, for arm dump operation, two valves, arm Lo and arm Hi, operate, and the remainder of the oil sent from the two hydraulic pumps, which is distributed to the swing circuit, is supplied to the head side of the arm cylinder. Ru.

The combined pressure oil is also sent to the boom cylinder through two valves, boom Lo and boom Hi, but the swing angle is approximately 45°.
Because of its small size, the raising of the boom is delayed relative to the swing and arm dump operations.Therefore, in addition to simultaneous boom raising, arm dump, and swing operations, a single boom raising operation is also performed to compensate for the above drawbacks.

Contrary to the above, when turning 180 degrees after excavating earth and sand to load it onto a vehicle, it takes longer to turn than lifting the boom and dumping the arm, so it is necessary to add an independent turning operation. When turning 90 degrees to load earth and sand onto a vehicle, the arm dump is delayed compared to the boom raising and turning, so it is necessary to compensate for this by adding an independent arm dump operation.

The present invention focuses on the above-mentioned conventional problems, and aims to provide a working machine oil amount distribution switching circuit that allows the driver to efficiently perform work without having to adjust whether the operating levers are operated simultaneously or independently. purpose.

[Means for Solving the Problems] In order to achieve the above object, a working machine oil amount distribution switching circuit for a hydraulic excavator according to the present invention has an upper rotating body and a lower traveling body, and a plurality of hydraulic pumps. In a hydraulic excavator equipped with a hydraulic excavator, at least one switching valve is provided in the pilot hydraulic circuit connecting the work equipment operating lever and the main operating valve, and the switching valve is operated to control the amount of oil discharged from the plurality of hydraulic pumps. The merging format has been changed to allow selection of the hydraulic circuit that distributes the optimal amount of oil for each type of work.

[Function] According to the above configuration, by operating the switching valve provided in the pilot hydraulic circuit connecting the work equipment operating lever and the main operating valve, the merging type of flow rate of the hydraulic pump can be adapted to the work type. As a result, the delay in the operation of some of the work equipment during simultaneous operation, which has been a problem in the past, has been resolved.
There is no need to adjust the operation of each operating lever.

[Example] Hereinafter, an example of the working machine oil amount distribution switching circuit for a hydraulic excavator according to the present invention will be described in detail with reference to the drawings P and Q.

In FIG. 1, a pilot hydraulic circuit 2a connected to a pilot valve 2 directly connected to a boom operating lever 1 is branched in the middle and connected to the spool ends of a boom Lo operating valve and a boom Hi operating valve. A switching valve 3 is provided on one side of the circuit. Further, the pilot hydraulic circuit 5a from the pilot valve 5 directly connected to the arm operating lever 4 is also branched in the middle and connected to the spool ends of the arm Lo operating valve and the arm DON operating valve, as described above, and the branch circuit A switching valve 6 is provided on one side. Furthermore, a switching valve 9 is provided in a pilot hydraulic circuit 8 connected from the control pump 7 via a pilot valve to the spool of the swing priority valve.

Said switching valve 3. 6. 9 are spring offset solenoid valves, which are operated by a signal current from a controller 10. Controller IO is mode selector switch 1
1, and the switching valve 3.1 is connected to the switching valve 3. 6. 9 is activated, and each pilot circuit can be connected or disconnected.

The mode changeover switch 11 is provided with four switches: standard, boom priority, arm priority, and swing priority.As shown in Table 1, when the boom priority switch is pressed, the changeover valves 6 and 9 are activated. However, the pilot circuit to the arm f (i) operation valve in Fig. 1 and the pilot circuit to the swing priority operation valve are closed, and the arm operates with only one pump's flow rate, and swing is no longer prioritized. Therefore, only the boom circuit Since the two pumps are combined, there is no longer a delay in the rise of the boom during ditch digging and soil removal in a 45° direction.

Similarly, when the arm priority switch is pressed, the switching valves 3.9 are activated, and when the swing priority switch is pressed, the switching valves 3.6 are activated to close the respective pilot circuits. In this way, the amount of oil is preferentially reserved for the most important hydraulic actuators for the selected mode. In addition, when the standard switch is pressed in the first position, all three switching valves do not operate, and the operating valves operate as before.

[Effects of the Invention] As explained above, according to the present invention, a changeover valve is provided in the pilot hydraulic circuit that operates each operation valve, and the driver can freely and easily select the priority mode required by the mode changeover switch. This eliminates the need to adjust the operation of each operating lever in order to synchronize the timing of each part of the working machine, resulting in the effect that the work machine operability of the hydraulic excavator is significantly improved.

[Brief explanation of the drawing]

FIG. 1 is a circuit explanatory diagram of a portion related to the present invention in a pilot circuit for operating valves of a hydraulic excavator equipped with a mode changeover switch and a changeover valve according to an embodiment, and FIG. 2 is a circuit diagram of a hydraulic excavator according to a conventional technology. FIG. 2 is a schematic explanatory diagram of a hydraulic circuit of a portion related to boom raising. 1...Boom operation lever 2a, 5a, 8...Pilot hydraulic circuit 3,
6. 9...Switching valve 4...Arm operating lever 10...Controller 11...Mote switching switch Patent applicant Komatsu Ltd. U Figure 1

Claims (1)

[Claims] In a hydraulic excavator having an upper rotating body and a lower traveling body and equipped with a plurality of hydraulic pumps, at least one switching valve is provided in a pilot hydraulic circuit connecting a work equipment operating lever and a main operating valve, A hydraulic excavator characterized in that the switching valve is actuated to change the merging format of the discharged oil amounts of the plurality of hydraulic pumps, and to select a hydraulic circuit that distributes the oil amount optimally for each work type. Work machine oil amount distribution switching circuit.