JPS591882B2 - Multiple hydraulic pump device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION According to the present invention, one engine drives at least one variable displacement expansion hydraulic pump 1 and at least one constant displacement cedar hydraulic pump, each of which has at least one The present invention relates to a multiple hydraulic pump device configured to operate actuators.

For example, in a hydraulic excavator that performs excavation work by operating each part of the excavation device consisting of a boom, arm, and packet installed on an upper revolving structure using a boom cylinder, arm cylinder, and packet cylinder, two pumps are used. -2
It has a pulp-type hydraulic circuit configuration, and these two pumps and two pulps operate the boom cylinder, arm cylinder, packet cylinder, and in addition to these, the hydraulic motors of the left and right traveling devices and the swing motor that drives the upper revolving structure. The control is activated.

However, with these conventional hydraulic circuit configurations, it is difficult to combine the swing system with large inertial force and other actuators, so in recent years, in order to improve this, one additional hydraulic pump has been added, and this third hydraulic pump is used. A configuration in which the rotation system is independent has been adopted.

However, in this case, there are three hydraulic pumps, and when these are operated at full capacity, the problem arises that the engine output is insufficient compared to the conventional case of two pumps.

To solve this problem, it would be better to improve the engine horsepower compared to the conventional one, but this means that the engine output cannot be fully utilized when the turning operation is not performed, so it is important to use the engine output effectively. There are some difficulties in this.

The present invention has been made in consideration of the above-mentioned problems, and it is possible to efficiently distribute the output of one engine to a plurality of actuators such as a work machine and a traveling device, and to make it possible to efficiently distribute the output of one engine to a plurality of actuators such as a work machine and a traveling device. It is an object of the present invention to provide a multiple hydraulic pump device that can be driven by a single engine with an output smaller than the full output without causing engine stall.

The configuration will be explained below based on the embodiment shown in the drawings.

In the figure, reference numerals 1, 2, and 3 denote first, second, and third pumps, which are driven by the same engine 6.

Of the above pumps, the first and second pumps 1 and 2 constitute a main pump, and the oil discharged from the first pump 1 is pumped through the right travel operation valve 4a, the boom operation valve 4b, and the arm operation/operation valve 4c. The oil discharged from the second pump 2 flows into the second operating valve 5, which includes a right travel operating valve 5a, a packet operating valve 5b, and a boom operating valve 5c.

On the other hand, the oil discharged from the third pump 3 is flowing into the swing operation valve 7.

8 is a swing motor. The first and second hydraulic pumps 1,
2 is of a variable discharge type, and its flow rate is controlled by a servo valve 9.

That is, the adjusting member 1a, 2a of each pump 1.2 is connected to a servo rod 10, which in turn is connected to a piston 12 fitted in a servo cylinder 11.

The servo cylinder 11 is composed of a cylinder 11a, a spring bearing member 13b integrally connected thereto, and a piston 12 fitted into the cylinder 11a.

The piston 12 is biased by a spring 13 against a member 13a.

The biasing direction by this spring 13 is the adjustment member 1a.

2a is moved in the direction of increasing the discharge amount.

The end faces of the piston 12 are stepped, and between each end face and the cylinder 11a are hydraulic chambers 14a, 14b, which are connected to first and second hydraulic pump circuits, respectively.

The servo cylinder 11 is slidably fitted into another cylinder 15 fixed to the pump body.

A spring 16 is interposed between the bottom of the cylinder 15 and the spring bearing member 13b of the servo cylinder 11, which biases the servo cylinder 11 in the direction of increasing the discharge amount of the adjusting members 1a and 2a of the pump 1°2. It is.

Further, in the cylinder 15, a hydraulic chamber 17 in which a hydraulic pressure is generated in a direction that biases the servo cylinder 11 in a direction opposite to the biasing force of the spring 16 is provided opposite to the spring bearing member 13a. A discharge circuit of the third hydraulic pump 3 is connected to 17 via a pilot circuit 18 .

In the above configuration, when operating the work equipment and the traveling device, it is done by operating the first and second operating valves 4 and 5, and at this time, the oil discharged from the first and second hydraulic pumps 1 and 2 is used.

At this time, since the swing operation valve 1 is in the neutral position, the third pump is completely drained and does not become a load on the engine.

At this time, the first and second hydraulic pumps 1 and 2 are adjusted by the servo valves 9 according to the respective hydraulic circuit pressures.

Next, when the swing operation valve 7 is switched to perform swing work while operating the work equipment and traveling device, the third hydraulic pump 3
Pressure is generated in the circuit, and the swing motor 8 is driven.

In this way, this third hydraulic pump 30 circuit pressure acts on the hydraulic chamber 11 of the servo valve 9.

When a predetermined hydraulic pressure is applied to this hydraulic chamber 17, the entire servo cylinder 11 moves together with the piston 12 against the urging force of the spring 16, and the adjusting member 1a of each pump 1, 2 is moved.
, 2a are operated via the servo rod 10 in the direction of decreasing the discharge amount, thereby reducing the discharge amount of both pumps 1 and 2.

At the same time, the discharge pressures of both pumps 1 and 2 at this time act on the respective hydraulic chambers 14a and 14b of the servo cylinder 11, and the piston 12 of the servo cylinder 11 balances the acting force due to the discharge pressure at that time with the spring 13. As a result, the stationary one-pump pumps 1 and 2 are controlled in a state where the discharge amount is reduced.

That is, the discharge characteristics of each pump as a whole when actuating an actuator other than the swing motor 8 are determined by the hydraulic pressure acting on the hydraulic chambers 14a', 14b and the spring, depending on the discharge pressure of the first and second hydraulic pumps 1, 2. It is balanced by the urging force of 13.

On the other hand, when the swing motor 8 is operated, the discharge characteristics of each pump as a whole are determined by the discharge pressure of the first and second hydraulic pumps 1 and 2, the hydraulic pressure acting on the hydraulic chambers 14a and 14b, and the biasing force of the spring 13. In addition to the balance, a balance between the discharge pressure of the third hydraulic pump 3, the hydraulic pressure acting on the hydraulic chamber 17 of the cylinder 15, and the spring 16 is added, and the servo cylinder 11 controls the first and second hydraulic pumps 1 and 2. is controlled so that its discharge amount is reduced compared to when the swing motor 8 is not operated, and the horsepower required to drive the first and second pumps 1 and 2 is reduced.

The present invention is as described above, and one engine includes at least one variable displacement cedar hydraulic pump 1, 2 and at least one
In a multiple hydraulic pump device, the fixed capacity cedar hydraulic pumps 3 are driven, and each of these hydraulic pumps operates at least one actuator, corresponding to the number of the variable capacity cedar hydraulic pumps 1.2. A piston 12 is provided with several steps and is fitted into the cylinder 11a so that the discharge pressure of each variable displacement cedar hydraulic pump 1, 2 acts on each step. First and second hydraulic chambers 14a facing each other.

The first spring 13 biasing toward the 14b side and the cylinder 1
1a and a spring support member 13a that supports the first spring 13, a servo cylinder 11 is constructed, and the piston 12 of this servo cylinder 11 is connected to the adjustment members 1a, 2a of the variable displacement cedar hydraulic pumps 1, 2. The servo cylinder 11 is connected to the fixed cylinder 15 fixed to the body side, and the entire servo cylinder 11 is connected to the variable displacement cedar hydraulic pump 1 between the fixed cylinder 15 and the servo cylinder 11. , 2 adjustment members 1a, 2a in the direction of increasing the discharge amount, and a mechanism for moving the servo cylinder 11 in a direction that resists the urging force of the second spring 16. A third hydraulic chamber 17 generating a hydraulic pressure of can be efficiently distributed to multiple actuators such as work equipment and traveling equipment,
Each work machine can be driven by one engine with an output smaller than the total output required for each work machine without causing engine stall.

[Brief explanation of the drawing]

The drawing is a hydraulic circuit diagram of a hydraulic excavator according to the present invention. 1.2.3 is a hydraulic pump, 6 is an engine, 9 is a servo valve, 15 is a cylinder, 16 is a spring, 17 is a hydraulic chamber, and 18 is a pilot circuit.

Claims (1)

[Claims] Eleven engines include at least one variable displacement expansion hydraulic pump 1, 2 and at least one constant displacement cedar hydraulic pump 3.
and a multiple hydraulic pump device in which each of the hydraulic pumps operates at least one actuator, comprising a number of stages corresponding to the number of the variable displacement expansion hydraulic pumps 1 and 2. Fits into the cylinder 11a,
A piston 12 in which the discharge pressure of each variable displacement expansion hydraulic pump 1, 2 acts on each stage, and hydraulic chambers 14a, 14b in which the piston 120 faces the stage part.
A servo cylinder 11 is constituted by a first spring 13 that urges the side, and a spring support member 13a that is coupled to the cylinder 11a and supports the first spring 13. A fixed cylinder 1 is connected to the adjusting members 1a and 2a of a variable displacement expansion hydraulic pump 1゜2, and the servo cylinder 11 is fixed to the body side.
5, and the entire servo cylinder is inserted between the fixed side cylinder 15 and the servo cylinder 11. A third spring 16 is provided with a second spring 16 that urges the servo cylinder 2a in the direction of increasing the discharge amount, and generates hydraulic pressure that moves the servo cylinder 11 in a direction that resists the urging force of the second spring 16. A multiple hydraulic pump device characterized in that a third hydraulic chamber 1γ is provided, and the constant displacement cedar hydraulic pump 3 is connected to the third hydraulic chamber 17.