JPS5923101Y2 - Hydraulic excavator hydraulic circuit - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an improvement of the hydraulic circuit of a hydraulic excavator.

In excavation work using a hydraulic excavator, combined movements of each actuator are required to increase work efficiency.

The present invention aims to provide a hydraulic circuit that can ensure the operation of each actuator even in the case of multiple operations and improve the above-mentioned work efficiency, and will be described below with reference to the accompanying drawings and in comparison with the conventional technology.

1-2 show conventional hydraulic circuits.

FIG. 1 shows a parallel circuit system of two pumps 1 and 2, which has been widely used.

However, the simultaneous operation of multiple operations is not perfect; for example, during the frequently used combined operation of the arm and swing, the pressure oil from pump 1 is introduced into either the swing or the arm, whichever has the smaller load, making the other operation uncertain. Met.

The same can be said for the packet/boom parallel circuit of pump 2.

In order to solve the drawbacks of the circuit shown in FIG. 1, a triple pump circuit as shown in FIG. 2 is known.

However, because the pressure oil of pumps 1, 2, and 3 is completely fixed with 1 rotating, 2 arm, and 3 packet and boom, the disadvantage is that the energy cannot be used effectively when each actimator is operated independently. be.

For example, in the case of single rotation operation, energy usage is pump 1
In the case of arm single operation, pump 2 only, etc.

Also, the energy distribution of this circuit is to maintain straight running.
Pump 2 and pump 3 have the same capacity, and further, the capacity of pump 1 is limited to a small value due to the operational balance of each actuator.

FIG. 3 shows a hydraulic circuit according to the present invention, in which pressure oil generated by hydraulic pumps 1, 2.3 connected to the output shaft of a power source 15 mounted on a hydraulic excavator is transferred to each operation valve 6.7. 8
By guiding and operating the operating valve 6.7.8,
It controls by distributing pressure oil to each actuator 9-14.

Now, the pressure oil of the hydraulic pump 1 is connected to a single valve 6 in a pipe, and an unload valve 4 is provided in the pipe to prevent the engine from stopping due to overload.

The pressure oil of the hydraulic pump 2 is connected to a triple parallel valve 7 via piping, and the pressure oil that has passed through the center bypass joins the single valve 6.

Further, a sequence valve 5 is arranged in parallel between the hydraulic pump 2 and the triple valve 7, so that pressure oil flows in parallel to the valves 6 and 7 according to the load on the single valve 6.

Pressure oil of the hydraulic pump 3 is connected to a triple parallel valve 8 through piping.

Each control valve 16-22 is 16, 9.17, 10.18, 11, 19, 12.20, 13.21, and 14.22 for each 7'; and 9
The actuators are connected to each other by piping, and each actuator is controlled.

The pressure oil to the hydraulic cylinder 10 is connected to pipes 17 and 10, and 22 and 10 to form a confluence circuit, and the control valves 17 and 22 are operated in conjunction to control the hydraulic cylinder 10.

Now, in the circuit shown in Fig. 3, if each actuator is determined as follows: 9 nib cylinders, 10 nib cylinders, 11: swing motor, 12: travel motor,
13: Travel motor, 14: When used as a packet cylinder,
As shown in the following table, the amount of pressurized oil flowing through each actuator 9 to 14 makes the combined operations, excluding the traveling operation, almost independent.

Further, in the case of this embodiment, since the vehicle is required to travel in a straight line, it is necessary to equalize the pressure oil supplied to the travel motors 12 and 13.

Therefore, the discharge amount 13 l/min of the hydraulic pump 2 and the discharge amount Cl/min of the hydraulic hope 3 are made equal.

With the amount of pressure oil flowing into each actuator, according to the present invention, no actuator stops even if multiple operations are performed.

Therefore, the drawbacks of known circuits are completely covered, and it has become possible to greatly improve simultaneous operation and workability.

That is, by appropriately selecting the pressure set of the sequence valve 5 using the unload valve 4 in Fig. 3, the working speed is faster in light load work than in the case of the circuit shown in Fig. 1, and in heavy load work. almost the same speed is ensured.

In particular, the simultaneous operation of swing and arm, which is the combined operation that was the biggest difficulty in the past, has been significantly improved.

[Brief explanation of the drawing]

1 and 2 show circuits of a known hydraulic excavator. FIG. 3 shows a hydraulic circuit according to the present invention. In the diagram, 1, 2, 3... hydraulic pump, 4...
...Unload valve, 5...Sequence valve, 6...Single valve, 7,8...
- Triple parallel valve, 9, 10.14... Hydraulic cylinder, 11.12.13... Hydraulic motor 16-22... Control valve.

Claims (1)

[Scope of utility model registration request] A triple pump consisting of pump 1 (discharge amount A), pump 2 (discharge amount B), and pump 3 (discharge amount C), and an unload valve 4 that is connected to the pump 1 through a pipe line and installed in parallel. A single valve 6 connected to the pump 2 and a triple parallel valve 7 connected to the pump 2 through a pipeline are provided. 6, and the hydraulic pump 2
A hydraulic circuit for a hydraulic excavator, characterized in that a sequence valve 5 is arranged in parallel between the three-unit halal valve 7 and the three-unit halal valve 7, and pressure oil from the hydraulic pump 2 can be supplied to the single-unit valve 6.