JPS6133077Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a hydraulic circuit for a chuck device using a hydraulic cylinder, and particularly to a hydraulic circuit suitable for a case where a chuck portion using a hydraulic cylinder rotates.

Hydraulic cylinders have conventionally been widely used as means for holding workpieces, and are widely used not only in the field of machine tools but also in other fields.

By the way, chuck devices in a fixed state where the chuck part does not rotate are usually piped with hydraulic hoses, and if the pressure in the hydraulic cylinder decreases, it can be pressurized by a hydraulic source such as a hydraulic pump, so that it can be used during work. The crimp will not come loose.

However, a chuck device whose chuck part is rotated by a hydraulic cylinder, for example, an excavator that excavates underground to drill a hole, as shown in Fig. 1, rotates the casing a to be drilled. Therefore, it is a device for checking the casing, and rotation is applied from a motor c of a drive part b supported by a main pillar (not shown) to a rotating member g via a reduction mechanism d and gears e and f. This rotation is applied to the casing a through a chuck device h, and this chuck device h has a pair of hydraulic cylinders 2, 2, as shown in plan view in FIG. , one end of which is pivotally supported by the outer casing on the rotating member g side, and the other end of i is connected to the hydraulic cylinder 2,
The shoes i, i are crimped onto or separated from the circumferential surface of the casing a by expanding and contracting the shoes i, i, and the rotating member g and the casing a are made to separate from each other by being crimped onto the circumferential surface of the casing a. For those that are designed to rotate as one,
It is difficult to constantly supply pressurized oil to the hydraulic cylinder, and it has to be supplied via a swivel device, which has the disadvantage that the chuck device as a whole becomes extremely large.

Therefore, a chuck device has been proposed in which a hydraulic cylinder of the chuck device and a hydraulic power source are connected to operate the chuck when the chuck device is in a non-rotating state, and then the hydraulic power source is disconnected.

However, over time, hydraulic oil leaks from the pressurized side to the low-pressure side of a hydraulic cylinder that has been disconnected from the hydraulic power source, and this leaked hydraulic oil acts on the hydraulic cylinder as back pressure, gradually loosening the chuck.
It is unsuitable for applications that require a chuck state to be maintained for a long period of time.

The present invention was developed in view of this, and by adding a check valve and an accumulator to the hydraulic circuit of a rotating chuck device, the hydraulic pressure remains constant even if the hose is removed after pressurization. The purpose of this invention is to provide a hydraulic circuit that allows the pressurized side of the cylinder to remain pressurized.

Hereinafter, the embodiments of the present invention will be explained as shown in FIG. 1 and FIG.
Components common to those in FIG. 2 will be described with the same reference numerals.

The hydraulic circuit of the check device according to the present invention includes a crimping circuit 4 extending from one of the pair of pilot check valves 1 to the rod side 3 of the hydraulic cylinder 2, and a crimping circuit 4 extending from the other of the pilot check valves 1 to the head side 5 of the hydraulic cylinder 2. In the chuck device, a check valve 7 operated by pilot pressure from the crimping circuit 4 is provided in the middle of the disconnection circuit 6, and an accumulator 8 is directly connected to the pilot check valve 7. It is something that can be done.

The pilot check valves 1 are a pair and are integrally constructed, one of which is connected to the crimping circuit 4 for high pressure, and the other to the disconnection circuit 6 for low pressure, both of which are connected to pressurized pressure. It is designed not to let you escape.

The hydraulic cylinder 2 is composed of a plurality of cylinders,
When chucking a workpiece, the rod is compressed and crimped; when chucking, the rod is extended and removed.

The crimping circuit 4 includes a portion from the pilot check valve 1 to the flow divider 9, and a portion branching from the flow divider 9 to the pair of hydraulic cylinders 2.
The flow divider 9 is further branched from the flow divider 9 to the throttle valve 1.
0 is provided, and an accumulator 11 is provided in front of it.
is provided.

Further, the detachment circuit 6 is configured to branch off midway in order to connect to the head side 5 of the plurality of hydraulic cylinders 2.

The check valve 7 is constructed so that it will not open unless there is a pilot pressure that is four times or more the secondary side pressure of the check valve 7, and the accumulator 8 connected to the check valve 7 is moved from the rod side 3 to the head side 5. This is to absorb leaked oil, and since the gas pressure is as low as 5 kg/cm ² , it is protected by the check valve 7.

The flow divider 9 is for synchronizing the movements of the plurality of hydraulic cylinders 2, 2, and the accumulator 11 is for accumulating pressure and pressurizing the crimping circuit 4 to maintain the crimping force. be.

Further, the throttle valve 10 is connected to the accumulator 11.
This is to prevent the pressure oil accumulated in the pipe from suddenly flowing at a large flow rate.

From the crimping circuit 4, one pilot pipe 12 is connected to the check valve 7, and as mentioned above, the pilot pipe 12 is so arranged that it will not open unless the pressure on the secondary side of the check valve 7 reaches four times or more. It's summery.

The hydraulic circuit of the check device according to the present invention is removably connected by a coupler 16 between the pilot check valve 1 and a separately provided directional control valve 15.

In the figure, 13 and 14 are pressure gauges, and 17 is a tank.

Next, the operation will be explained.

1 When opening the chuck.

First, when the directional control valve 15 is switched from the B position to the A position shown in the figure, the pressure oil passes through the pilot check valve 1 and enters the head sides 5, 5 of the hydraulic cylinders 2, 2 via the disconnection circuit 6 on the low pressure side. At this time, since the check valve 7 does not open due to the low pressure, no pressure is applied to the accumulator 8 either. and the rod side 3 of the hydraulic cylinders 2, 2,
The oil No. 3 becomes return oil and is returned to the tank 17 from the directional control valve 15 via the flow divider 9 and the pilot check valve 1 located in the middle of the crimping circuit 4.

2. When checking.

First, when the directional control valve 15 is switched to the C position,
Pressure oil is introduced from the pilot check valve 1 into the crimping circuit 4, enters the flow divider 9, is divided into equal parts, and enters the rod sides 3, 3 of the hydraulic cylinders 2, 2. Therefore, the return oil is returned to the tank 17 from the head side 5, 5 via the pilot check valve 1 and the directional control valve 15.

While the rod is moving, the check valve 7 will not open unless the pressure in the crimping circuit 4 becomes four times or more the pressure in the detaching circuit 6, so the accumulator 8 can be protected from high pressure.

However, when the rod stops moving when it hits something to be checked, the pressure in the crimping side circuit 6 increases, and this pressure is accumulated in the accumulator 11 and acts on the check valve 7 as pilot pressure. Open check valve 7. Then, the oil amount in the withdrawal side circuit 6 returns to the tank 17, and the pressure becomes zero. Due to this zero pressure, the opening of the check valve 7, and the gas pressure of the accumulator 8, the residual oil remaining in the accumulator 8 is completely discharged.

Next, when the directional control valve 15 is returned to the B position, the pressure oil from the directional control valve 15 to the coupler 16 returns to the tank 17, and the oil between the pilot check valve 1 and the hydraulic cylinders 2, 2 is transferred to the accumulator 1.
It is pressurized by pressure oil stored in 1,
In this state, remove the coupler 16.

3. When chucked for a long time.

When the coupler 16 is removed, pressure oil always leaks from the rod side 3 of the cylinder 2, which is the high pressure side, to the head side 5, which is the low pressure side, so in the conventional hydraulic circuit, the oil leaking to the head side 5 is reversed. This results in back pressure pushing the rod side 3, and the rod side 3
As the pressure on the head side 5 rises until it is balanced, the chuck force drops rapidly, but in the circuit of the present invention, the oil leaking to the head side 5 is absorbed by the accumulator 8 provided in the withdrawal circuit 6. As a result, the pressure rise on the head side 5 is reduced and slowed down, and long-term chuck operation becomes possible.

In the above embodiment, a crimping circuit 4 is connected to the rod side 3 of the hydraulic cylinders 2, 2 in the chuck device.
Further, a detachment circuit 6 is connected to the head side 5 to form a pressure side and a low pressure side, but a crimping circuit is connected to the head side and a detachment circuit is connected to the rod side to form a pressure side and a low pressure side. The chuck operation may be performed by the rod extension operation.

As explained above, the hydraulic circuit of the chuck device according to the present invention is provided with a check valve in the disconnection circuit of the conventional hydraulic circuit, and this check valve is operated by the pilot pressure from the crimping circuit. By installing an accumulator directly connected to the check valve, the problems of the conventional system have been solved, and the check state can be maintained for a long time, and the hydraulic swivel device required for large checks is no longer required, reducing equipment costs. Various effects can be obtained, such as reducing power consumption and eliminating the need for a complicated circuit mechanism.

[Brief explanation of the drawing]

Fig. 1 is a schematic sectional view showing a part of an excavator to which a chuck device according to the present invention is applied, Fig. 2 is a plan view of the chuck device in Fig. 1, and Fig. 3 is a diagram showing an embodiment of the present invention. This is the hydraulic circuit shown. 1...Pilot check valve, 2...Hydraulic cylinder, 3...Rod side, 4...Crimping circuit, 5...
...Head side, 6...Disengagement circuit, 7...Check valve, 8...Accumulator, 12...Pilot conduit.

Claims (1)

[Scope of utility model registration request] A chuck device comprising a crimping circuit extending from one of a pair of pilot check valves to a pressurizing side of a hydraulic cylinder, and a disengaging circuit extending from the other of the pilot check valves to a low pressure side of the hydraulic cylinder. A chuck valve operated by pilot pressure from the crimping circuit is provided in the middle, and an accumulator is directly connected to the chuck valve. A hydraulic circuit for a chuck device characterized by absorbing pressure oil leaking to a lower pressure side.