JPS5980509A - Operation circuit for plural fluid pressure actuator - Google Patents

Abstract

PURPOSE:To smoothly conduct turning and boom operation in parallel with each other by introducing the first pilot pressure and the second pilot pressure into a pilot switching valve so that the initial turning is conducted without delay, and after the start of turning, a boom is quickly operated. CONSTITUTION:In a pilot switching valve 9, the first pilot pressure introduced from the first fluid pressure actuator circuit 4 exerts upon the spring 16 side, and a fluid fed with pressure by a switching valve 19 adapted to open interlocking with the opening of a switching valve 7 for a boom cylinder exerts upon the pressure spring 15 side as the second pilot pressure. If the working fluid has high pressure for producing large turning torque required for the initial turning, a hydraulic motor for turning is separately operated by the total output of the first hydraulic pump. When the first pilot pressure becomes lower than the second pilot pressure, the pilot switching valve 9 is opened to let a part of the working fluid in the first hydraulic pump system in the second hydraulic pump system, thereby operating the boom cylinder.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides, when a plurality of fluid pressure actuators each having a different pressure source have different initial loads, the working fluid pressure of the actuator with a large initial load is reduced to a certain value or less. This relates to a pressure fluid operation circuit that does not allow fluids to merge into the operating fluid circuits of other fluid pressure actuators, and allows smooth operation of equipment with a large initial load without delaying the operation of multiple fluid pressure actuators at the same time. The present invention relates to an actuation circuit that allows quick operation of other hydraulic actuators.

Below, we will explain a conventional example of a hydraulically operated power shovel.A power shovel has a hydraulic motor that turns a swinging machine on a traveling vehicle body, a boom cylinder that lifts up and down a boom whose base end is pivoted to the swinging machine, and a boom cylinder that is attached to the boom. The hydraulic motor is operated by a first hydraulic pump in order to effectively utilize the output of the engine mounted on the aircraft. The boom cylinder, the arm cylinder, and the bucket cylinder each have a first hydraulic actuator circuit supplied with fluid, and each of the boom cylinder, arm cylinder, and bucket cylinder has a second hydraulic actuator circuit supplied with working fluid from a second hydraulic pump. , the first hydraulic actuator circuit supplies working fluid from the first hydraulic actuator circuit to the second hydraulic actuator circuit as necessary for actuators that require a large amount of working fluid, such as boom cylinders, arm cylinders, and bucket cylinders. A communication circuit is formed that connects the fluid pressure actuator circuit and the second fluid pressure actuator circuit.

In such an operating circuit, for example, when operating only the swing hydraulic motor with a large initial load,
All of the working fluid from the first fluid pressure actuator circuit is supplied to the hydraulic motor, and the hydraulic motor is operated for a period of time from the time of startup to the point where swing motion inertia is applied, that is, a large swing torque, as shown by the solid line in FIG. The first time you need
The working fluid pressure supplied from the hydraulic pump to the hydraulic motor is high, and the torque generated by the hydraulic motor is large, so the aircraft can start turning without delay, and when turning motion inertia is applied to the aircraft, As the turning torque becomes smaller, the working fluid pressure also gradually decreases.

However, for example, when operating the swing hydraulic motor and the boom cylinder at the same time, the working fluid in the first hydraulic actuator circuit requires a large swing torque at the start of the swing, so the second fluid in the boom cylinder Since the working fluid in the first hydraulic actuator circuit has a higher pressure than the working fluid pressure in the hydraulic actuator circuit, the working fluid in the first hydraulic actuator circuit flows into the second hydraulic actuator circuit which has a lower pressure, and as shown by the broken line B in FIG. As shown in the figure, the fluid pressure supplied to the swing motor decreases and the torque at the initial turn is insufficient, making it difficult for the aircraft to turn quickly, resulting in a delay in the initial movement of the aircraft. This lacked smoothness and was a significant hindrance to improving work efficiency.

The present invention eliminates the above-mentioned drawbacks, and includes a first hydraulic pump system that supplies working fluid to the swing hydraulic motor, and a second hydraulic pump that supplies working fluid to the boom cylinder, arm cylinder, and bucket cylinder. A communication circuit is configured between the communication circuit and the pilot switching valve provided in the communication circuit, and a first biloft pressure caused by the working fluid from the first hydraulic pump system and another biloft pressure belonging to the second hydraulic pump system are applied to the pilot switching valve provided in the communication circuit. A second pilot pressure by pressure fluid from the hydraulic system is introduced, and when the pilot pressure from the first hydraulic pump system is above a certain value, that is, at the time of the initial movement of the aircraft, the working fluid is required for the initial movement of the turn. When there is a high pressure that produces a large swing torque, the pilot pressure from the other hydraulic system does not open the pilot switching valve, and the swing hydraulic motor is operated independently by the full output of the first hydraulic pump. After the first hydraulic pump is activated and a turning movement inertia is generated in the aircraft, the discharge pressure of the first hydraulic pump drops below a certain value as shown by the solid line in FIG. When the pilot pressure from the system becomes lower than the pylon I pressure from other pump systems belonging to the second hydraulic pump system, the viroft switching valve opens and a part of the working fluid of the first hydraulic pump system is released. The flow goes to the second hydraulic pump system and operates the boom cylinder, etc., so the initial turning of the aircraft is carried out without delay, and after the 11 aircraft start turning, the boom etc. are operated quickly, allowing the aircraft to turn and boom operation at the same time. They can be operated smoothly in parallel.

Hereinafter, an embodiment of the present invention will be described with reference to FIGS. 2 to 4. A first hydraulic pump l having a swing morph monthly switching valve 3 between a first hydraulic pump l and a swing motor 2 which is a first fluid pressure actuator. A fluid pressure actuator circuit 4 is configured, and a second fluid pressure actuator circuit 8 having a boom cylinder switching valve 7 is arranged between the second hydraulic pump 5 and the boom cylinder 6, which is the second fluid pressure actuator. It is configured. The first fluid pressure actuator circuit 4 and the second fluid pressure actuator circuit 8 are connected by a communication circuit 10 having a pilot switching valve 9.

As shown in FIGS. 3 and 4, the pilot switching valve 9 forms a recess 14 into which the rond 13' of the actuator 13 that slides in the pilot chamber formed in the valve housing 12 at both ends of the spool valve body 11 is fitted. A pressure spring 15 is interposed on the outer surface of the actuator 13, and a return spring 16 is interposed on the inner surface. The first pilot pressure introduced from the first fluid pressure actuator circuit 4 acts,
Further, on the pressure spring 15 side of the pilot chamber, a switching valve 19 that opens in conjunction with the opening of the boom cylinder switching valve 7 allows fluid to be pumped by a pilot pressure pump 20 through a second pilot pressure flow path 21. Acts as pilot pressure for 2.

Therefore, when operating the swing motor 2 independently, the switching valve 3 is operated to supply the working fluid of the first hydraulic pump 1 to the swing motor 2 through the first fluid pressure actuator circuit 4, and the communication circuit IO It is supplied to the pilot switching valve 9 through the.

In this case, the swing motor 2 operates, but a portion of the working fluid in the first fluid pressure actuator circuit 4 passes from the shuttle valve 17 to the first pilot pressure passage 18 to the pilot switching valve as shown in FIG. 9 Biroso on both ends! - The spool valve body 1 is introduced into the return spring 16 side of the chamber and pushes the actuator 13 outward against the force of the pressure spring 15.
Since valve 1 does not move and is held in the closed state, communication circuit 10
The working fluid does not flow into the second fluid pressure actuator circuit 8, and the working fluid pumped by the first hydraulic pump 1 is supplied to the first fluid pressure actuator with the pressure change shown by the solid line in FIG. It is consumed only for the swing operation of the hydraulic motor 2.

Next, the swing motor 2, which is the first fluid pressure actuator,
and a boom cylinder 6 which is a second hydraulic actuator.
When operating both at the same time, drive the first hydraulic pump l and the second hydraulic pump 5, open the swing motor switching valve 3 and the boom cylinder switching valve 7, and operate the switching valve 3. As described above, when the swing motor 2 operates, the first pilot pressure from the first fluid pressure actuator circuit 4 is applied to the return spring 16 side of the pilot chamber on both ends of the spool valve body 11 of the pilot switching valve 9. Pressure channel 18
The spool valve body 11 is held in the neutral position, that is, in the closed position.On the other hand, the switching valve 19, which opens in conjunction with the opening operation of the boom cylinder switching valve 7, allows pressure to be supplied from the pilot pressure pump 20. The fluid to be used is the second pi-so1-
The spool valve body 1 of the pilot switching valve 9 via the pressure flow path 21
The second pilot pressure acts on one of the 15 pressure springs in the first pilot chamber.

Therefore, the first pilot pressure and the second pilot pressure act on both sides of the actuator 13, and when the first pilot pressure is higher than the second nod pressure, that is, the initial movement of the rotating aircraft When the torque is greater than the initial torque of the boom, the spool valve body 11 maintains the open neutral position, and the first fluid pressure actuator circuit is supplied from the first hydraulic pump 1 to the swing motor 2. 4 does not flow into the second hydraulic actuator circuit 8, and all of the working fluid pumped from the first hydraulic pump 1 through the communication circuit 1o is supplied to the swing motor 2 and the swing machine act as the initial torque of the second hydraulic pump 5 to prevent delay in the initial swing operation, while the working fluid pumped from the second hydraulic pump 5 is
boom cylinder 6 via hydraulic actuator circuit 8 of
The boom operates regardless of the swinging motion of the swinging aircraft.

Then, after the initial motion of the swinging aircraft starts, the swinging torque gradually decreases due to the kinetic inertia of the swinging aircraft, and the first pilot pressure becomes smaller than the second pilot pressure. As shown in the figure, since the spool valve bodies t and 1 are moved inward in the valve opening direction, a part of the working fluid of the first fluid pressure actuator circuit 4 is transferred to the communication circuit 1 (from the pilot switching valve 9 through the second fluid pressure actuator circuit 8 and is supplied to the boot cylinder 6, the swinging aircraft makes an initial turn without delay, and after the aircraft starts turning, the boom is connected to the first fluid pressure actuator circuit 4. By merging some of the working fluids of the two, it is possible to promote rapid operation.

It goes without saying that in the above embodiment, an arm cylinder or a baggage sorting cylinder may be used instead of the boom cylinder as the second fluid pressure actuator.

As described above, the present invention connects fluid circuits that supply working fluid to each of a plurality of fluid pressure actuators with different initial loads through a communication circuit, and it is possible to operate each fluid pressure actuator independently. Instead, when multiple fluid pressure actuators are driven simultaneously, the working fluid supplied to the fluid pressure actuator with a large initial load does not immediately escape through the communication circuit to the working fluid of the fluid pressure actuator with a small initial load. , the fluid pressure actuator with a large initial load is supplied only to the fluid pressure actuator, so that the original fluid pressure actuator operates for the first time without delay, and after the fluid pressure actuator with a large initial load starts the initial operation, the turning torque is reduced due to the inertia of the turning motion of the aircraft. When the working fluid becomes below a certain value, part of the working fluid in the first fluid pressure actuator circuit joins the second fluid pressure actuator circuit to promote the operation of the second fluid pressure actuator. Since the operating speed of the 2 fluid pressure actuators can be increased, even if there is a difference in initial torque between multiple fluid pressure actuators, multiple fluid pressure 7 actuators can be operated simultaneously without delay, making operation easier. At the same time, it is possible to perform project work quickly and efficiently.

[Brief explanation of the drawing]

FIG. 1 is an operating pressure diagram of the first fluid pressure actuator with a large initial torque, and FIG.
Fig. 3 is a sectional view of the main part showing the closed state of the pilot switching valve of the present invention, and Fig. 4 G is a sectional view of the main part showing the main state of the pilot switching valve of the invention when the valve is opened. It is a diagram. 2...First fluid pressure actuator 4...First fluid pressure actuator circuit 5...Second
Fluid pressure actuator 6...Pilot switching valve 7...Branch circuit 9...Switching valve 10 of the second fluid pressure actuator circuit
...Second fluid pressure actuator circuit 18...First
Pyro/nod pressure flow path 21...Second pie pressure flow path Agent Patent attorney Yuyosuke - 1 other person

Claims (1)

[Claims] A pilot switching valve is provided in a communication circuit connecting a first fluid pressure actuator circuit with a large initial load and a second fluid pressure actuator circuit with a smaller initial load than the first fluid pressure actuator, each having a different pressure source. A switching valve for a first pilot pressure flow path and a second fluid pressure actuator circuit, which act as a first pilot pressure at both ends of the pilot switching valve. A second valve that opens in conjunction with the valve opening operation and applies a second pilot pressure from the pilot pressure pump.
When the first pilot pressure is lower than the second pilot pressure, the Byron I switching valve is opened and the working fluid in the circuit of the first fluid pressure actuator is connected. An operating circuit for a plurality of fluid pressure actuators, wherein a pilot operating element is provided at both ends of the pilot switching valve, a part of which merges into the circuit of a second fluid pressure actuator.