JPS6252090B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a bucket operating circuit that allows a hydraulic actuator such as a breaker or a gun drill to be operated using the same hydraulic circuit while the bucket is gripping a hydraulic actuator such as a breaker or a gun drill.

Generally, in order to operate two hydraulic devices at the same time, it is either necessary to configure their own hydraulic operation circuits, or to configure a parallel circuit from the middle of one of the hydraulic circuits via a switching valve, etc., and operate each hydraulic device separately. This is the actual situation.

Therefore, in the former case, each hydraulic circuit must be configured, and if the hydraulic equipment is located in a remote or narrow location, a long hydraulic circuit such as a hydraulic hose is required, which is troublesome to deal with.

In addition, in the latter case, there is no point unless the branch is located close to the hydraulic equipment, and a switching valve, etc. must be installed near the hydraulic equipment, and it is difficult to secure the mounting position, and the switching valve must be installed near the hydraulic equipment. This resulted in inconveniences such as the need for a control device to operate the valves, etc.

The invention related to the bucket operation circuit of Japanese Patent Application No. 54-014600 was made in order to solve the above-mentioned problems, and it provides pressure oil supply to the bucket closing side of the bucket opening/closing cylinder connected to the hydraulic power source via a reversible switching valve. A pilot-operated check valve is installed in the circuit, and a breaker, gun drill, etc. is installed between the reversible switching valve and the pilot-operated check valve and in a parallel circuit branched from the bucket opening side pressure oil supply circuit through a self-sealing coupling. A hydraulic actuator is installed, but if the operating circuit is such that the bucket opens when the bucket opening/closing cylinder is not activated, pressure oil is supplied from the pressure oil supply circuit on the bucket opening side. When not feeding pressure oil to the bucket opening/closing cylinder, the bucket door does not open because the return oil circuit is closed, but when gradually feeding pressure oil,
First, the pilot pressure rises due to the pressure oil, and the pilot operation check valve in the return oil circuit is opened, so the bucket opens under its own weight.Then, as the bucket tries to open itself, the pressure in the pressure oil supply circuit decreases. At the same time, the pilot pressure drops without being maintained and the check valve closes, and then the check valve is opened again by the gradually supplied pressure oil, and this state is repeated in a short period of time, causing the surging phenomenon. This caused problems such as abnormal noise from the pilot control check valve and rise in oil temperature.

The present invention is applicable to the case where the bucket door is structured to open when the bucket opening/closing cylinder is not in operation, from the branch part of the pilot pipe of the pilot operation check valve of the bucket door operation circuit of Japanese Patent Application No. 54-014600. The above problem is solved by interposing a throttle valve with a check valve that acts in that direction in the hydraulic circuit that runs through the bucket opening/closing cylinder to the pilot operated check valve.

The following will explain the embodiments shown in the drawings.

FIG. 1 shows the basic circuit of the present invention, in which 1 is a hydraulic power source such as a pump, 2 is a reversible switching valve such as a solenoid valve or a manual valve, and 3 is a bucket opening/closing cylinder. Pressure oil supply circuit a, which communicates with
The bucket closing side pressure oil supply circuit a of b is equipped with a pilot operated check valve 4 which is operated by pilot pressure applied through a pilot pipe branched from the bucket opening side pressure oil supply circuit b. A relief valve 5 and a check valve 6 are interposed between circuits a and b. Reference numeral 7 denotes a hydraulic actuator such as a breaker or a gun drill, which is connected to a parallel circuit a' between the reversible switching valve 2 and the pilot operation check valve 4 of the pressure oil supply circuit a and branched from the return oil circuit, that is, the bucket opening side pressure oil supply circuit b. , b' through self-sealing couplings 8, 8'. 9 is a tank.

The above configuration is the same as that shown in FIG. 1 of Japanese Patent Application No. 54-014600, but in this embodiment, a new feature is added between the branch part of the pilot pipe of the bucket opening side pressure oil supply circuit b and the bucket opening/closing cylinder 3. A throttle valve 30 with a check valve is installed in the hydraulic circuit, and the throttle valve 30 with a check valve has a structure that creates resistance when the flow flows toward the cylinder 3, but does not create resistance when the flow flows from the cylinder 3. It is.

FIG. 2 shows an embodiment in which the present invention is applied to a hydraulic excavator, and is basically the same as FIG. Since the reversible switching valve 2 and subsequent valves can be used as an example.

Reference numeral 11 denotes a hydraulic system for operating the bucket of the hydraulic excavator, and 12 denotes a bucket. The bucket 12 is opened and closed by a bucket opening/closing cylinder 13.

The hydraulic device 11 for bucket operation and the cylinder 1
A rotary joint 1 is connected to the bucket closing side pressure oil supply circuit a of the pressure oil supply circuits a and b that communicate with the rotary joint 1.
4. A swivel joint 15 and a pilot operation check valve 16 are installed, and the return oil circuit, that is, the bucket opening side pressure oil supply circuit b, is equipped with an electromagnetic or manual directional control valve 17, a rotary joint 14', and a swivel joint. In addition, between both pressure oil supply circuits a and b, there is a relief valve 18 that relieves the pressure on the bucket closing side of the bucket opening/closing cylinder, and a check valve 19 that allows flow only from the pressure oil side to the return oil side. communicated via.

20 is a hydraulic actuator such as a breaker or gun drill, and the actuator 20 is connected between the swivel joint 15 and the pilot operation check valve 16 of the pressure oil supply circuit a, and between the cylinder 13 and the swivel joint 15' of the return oil circuit b. They are connected to parallel circuits a' and b' branched from between, respectively, via self-sealing couplings 21 and 21'.

The pressure oil supply circuits a and b are lowered and hoisted by a reel 22 as the bucket 12 moves up and down. 23 is a tank.

The above configuration is the same as that shown in FIG. 2 of Japanese Patent Application No. 54-014600, but in this embodiment, a new feature is added between the branch part of the pilot pipe of the bucket opening side pressure oil supply circuit b and the bucket opening/closing cylinder 13. A throttle valve 40 with a check valve is interposed in the hydraulic circuit, and the throttle valve 40 with a check valve has a structure that provides resistance when the flow flows toward the cylinder 13, but does not provide resistance when the flow flows from the cylinder 13. It is.

In the embodiment shown in FIGS. 1 and 2, throttle valves 30 and 40 with check valves are interposed between the pilot pipe branch of the bucket opening side pressure oil supply circuit b and the bucket opening/closing cylinders 3 and 13. Although shown as an example, this throttle valve with check valve 30, 40
can also be interposed between the bucket opening/closing cylinders 3, 13 and the pilot operated check valves 4, 16 of the return oil circuit, that is, the bucket closing side pressure oil supply circuit a.

Next, its effect will be explained.

"Bucket opening/closing operation" Self-seal coupling 8, 8', 21, 2
By switching the reversible switching valve 2 with the valve 1' separated and self-sealed, the supply of pressure oil to the breaker or gun drill 7, 20 is cut off, so the operation is exactly the same as the conventional bucket opening/closing.

That is, when closing the bucket 12, if the reversible switching valve 2 is switched to the A port, the pressure oil flows through the reversible switching valve 2.
The return oil is supplied to the bucket closing side of the bucket opening/closing cylinders 3, 13 via the pilot operated check valves 4, 16, and the return oil is returned to the tanks 9, 23 via the return oil circuit b. At this time, the pressure oil or return oil passes through the check valve side of the check valve equipped throttle valve 30, 40 installed in the bucket closing side pressure oil supply circuit a or the return oil circuit b, and is not subjected to any resistance.

Conversely, when opening the bucket 12, when the reversible switching valve 2 is switched to the B port, pressure oil is supplied from the reversible switching valve 2 via the directional switching valve 17 or directly to the bucket opening side of the bucket opening/closing cylinders 3 and 13. At the same time, since the pilot pressure acts on the pilot operated check valves 4 and 16 to open the return oil, the pilot operated check valves 4 and 16 and the reversible switching valve 2
It is then returned to tank 9. At this time, the pressure oil or return oil is supplied to the throttle valve 3 with a check valve installed in the bucket opening side pressure oil supply circuit b or the return oil circuit a.
It passes through the throttle valve side of No. 0 and 40 and receives resistance, thereby preventing a surging phenomenon from occurring at the pilot operation check valve portion in the return oil circuit a.

"Operating the breaker or gun drill" When the breaker or gun drill 20 is inserted into the bucket gripping position with the bucket 12 opened by the bucket opening operation described above and the bucket closing operation is performed, the breaker or gun drill 20 is opened.
0 is grabbed by Bucket 12. Even if the supply of pressure oil to the bucket opening/closing cylinders 3, 13 is cut off in this state (unless the bucket opening operation is performed), the pressure in the bucket opening/closing cylinders 3, 13 will be maintained by the action of the pilot operated check valves 4, 16. Maintain this state.

Next, when the reversible switching valve 2 is returned to the neutral position and the directional switching valve 17 is switched to the B port, the bucket opening operation is performed, and the pressure oil on the bucket closing side is communicated with the tank and depressurized, and then transferred to the branch circuit. Self-sealing couplings 8, 8', 21, 2 for a', b'
1' to connect the branch circuits a' and b', and switch the reversible switching valve 2 to the A port to connect the pressure oil supply circuits a and b'.
When pressure oil is supplied to a', the bucket opening/closing cylinders 3, 13 are already sufficiently pressurized, so the pressure oil is supplied only to the breaker or gun drill 7, 20, and it operates while being gripped by the bucket 12. .

When the breaker or gun drill 7, 20 is activated, the bucket opening/closing cylinders 3, 13 may be pressurized more than necessary due to hydraulic pulsation of the breaker or gun drill 7, 20, but in this case, the relief valve 5, 18 is activated. and release the pressure oil.

In addition, as in the embodiment shown in Fig. 2, when the directional control valve 17 installed in the return oil circuit b is equipped with a breaker or gun drill,
3), the bucket door 12 will not be opened due to erroneous operation, and the breakers 7 and 20 will not be released by mistake, making it safe. In this embodiment, a breaker and a gun drill are used as examples of the hydraulic actuator provided in the branch circuit, but it goes without saying that other single acting actuators can also be used.

As described above, according to the present invention, the bucket gate can be opened and closed in exactly the same manner as before, and the bucket gate operation circuit can be used without providing a new breaker operation circuit or switching operation using a switching valve or the like. It is possible to operate the breaker while grasping it with the bucket, and it has the effect of making it easy to connect hydraulic piping to the breaker, etc. even when piping space is limited, such as by digging a hole. If the valve is structured to open during operation, it has the effect that abnormal noise and oil temperature rise of the pilot operated check valve will not occur.

[Brief explanation of the drawing]

FIG. 1 shows a basic circuit of the present invention, and FIG. 2 shows an embodiment in which the present invention is applied to a hydraulic excavator. 2... Reversible switching valve, 3, 13... Bucket opening/closing cylinder, 4, 16... Pilot operated check valve,
7, 20...Hydraulic actuator such as gun drill or breaker, 8, 8', 21, 21'...Self-seal coupling, 12...Bucket, 30, 4
0... Throttle valve with check valve.

Claims (1)

[Claims] 1. In a bucket operating circuit in which a hydraulic actuator such as a breaker is held in a bucket while working, a pilot operated check valve is installed in the pressure oil supply circuit on the bucket closing side of a bucket opening/closing cylinder connected to a hydraulic power source via a reversible switching valve. ,
A hydraulic actuator is attached via a self-seal coupling to a parallel circuit branched from the bucket opening side pressure oil supply circuit and between the reversible switching valve and the pilot operated check valve, and a hydraulic actuator is attached to the pilot pipe of the pilot operated check valve. A bucket operation circuit characterized in that a hydraulic circuit extending from a branch part to the pilot operation check valve via the bucket opening/closing cylinder is equipped with a throttle valve with a check valve that acts in that direction.