JPH0262404A - Hydraulic circuit for combined operation of special work machine - Google Patents

Abstract

PURPOSE:To make the other hydraulic actuator operative while an original special work machine is operating by interposing a protective relief value and a selector valve and constituting the selector valve to be capable of shifting form the position of open oil duct to the position of oil duct with throttle part when a special work machine and the other hydraulic actuator are operated in combination. CONSTITUTION:The working oil duct of a breaker 2 is in the state of open oil duct as a selector valve 17 does not operate to shift when the breaker 2 is individually operated. When the breaker 2 is operated in combination with, for example, a bucket cylinder 3, and the operation lever 20 of a remote control valve 9 is operated, the pressurized oil from a pilot pump 14 actuates a pilot selector valve 7 to make switching operation, and acts on the pilot pressure bearing part 18 to switch the selector valve 17. Thus, the oil pressure inside the working oil duct 27 on the upstream side of the selector valve 17 is raised, the pressurized oil is supplied to the breaker 2 as well as to the bucket cylinder 3, and the special work machine breaker 2 and other hydraulic actuator are operated in combination.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates primarily to a hydraulic circuit for complex operation of a special working machine mounted on a hydraulic excavator.

Prior Art FIG. 3 is a hydraulic circuit diagram of the prior art. In the figure,
1 is a work attachment installed on the front part of a hydraulic excavator (not shown), 2 is a breaker which is a special working device installed at the tip of work attachment l-1, 3 is a packet cylinder, and 4 is a relief valve for protecting the breaker 2. ,5,6
is a relief valve for packet cylinder 3, 7 is a pilot switching valve for packet cylinder 3, 8 is a pilot switching valve for breaker 2, 9 is a remote control valve for packet cylinder 3, 10
．． 11 is a pilot valve of the remote control valve 9, 12 is a main pump, 13 is a main relief valve, 14 is a pilot pump, 15 is a pilot relief valve for the pilot pump 14, and 16 is an oil tank.

Next, the configuration of a conventional hydraulic circuit will be described with reference to FIG. Pilot I-switching valve 7 for controlling various hydraulic actuators
, 8 etc. are connected in parallel, and the pressure oil from the main pump 12 is transferred to the pilot switching valves 7, 8 by operating the operating lever.
They are supplied to the hydraulic actuators 3, 2, etc., respectively. The hydraulic actuator 2 is a special working machine, for example, a breaker, and the operating circuit of the breaker 2 includes a relief valve 4 for protecting the breaker 2.
are placed.

Problems to be Solved by the Invention Special working machines such as breakers and tilting packets are sometimes attached to the work attachment of a hydraulic excavator to perform work. The operating circuit of the special working machine is provided with a relief valve for protection against the operation of the special working machine. The relief setting pressure of the protective relief valve is lower than the operating pressure of the other hydraulic actuators. Also,
Since this protective relief valve is arranged to allow the special working machine to operate without any trouble, its relief set pressure cannot be increased or adjusted. For this reason, for example, if the packet cylinder was operated in combination while the breaker was operating, the pressure oil would preferentially flow to the breaker because the operating pressure of the packet cylinder was high, and the packet cylinder would not operate. In other words, even if an attempt is made to change the position of the breaker while the breaker is operating, the packet cylinder will not move, making complex operations difficult and problematic.

This invention solves the above-mentioned problems and provides a hydraulic circuit for complex operation that enables other hydraulic actuators to operate while a special work machine is in operation. A switching valve with an oil passage position with a throttle part is installed in the hydraulic oil passage that communicates the protective relief valve placed in the operating circuit of the machine with the pilot switching valve that controls the special work machine. When performing combined operation of the special work machine and other hydraulic actuators, the above-mentioned switching valve is configured to be able to switch from the open oil passage position to the throttled oil passage position, allowing only the special work machine to be operated independently. Sometimes, the switching valve installed in the hydraulic oil passage of a special working machine does not switch. The switching valve is in the open oil path position.

When the special working machine and other hydraulic actuators are operated in combination, the switching valve is switched from the open oil passage position to the throttled oil passage position. Therefore, the oil pressure in the hydraulic oil passage upstream of the switching valve increases, so that pressure oil is supplied to the special working machine and is also sent to other hydraulic actuators.

C. In the above manner, when a special working machine and another hydraulic actuator are operated in a combined manner, both can be operated at the same time.

EMBODIMENTS Hereinafter, a hydraulic circuit for complex operation of a special working machine according to the present invention will be explained in detail based on the drawings. FIG. 1 is a hydraulic circuit diagram for complex operation according to the present invention. In the figure,
Components that use the same components as those in the prior art are not given the same reference numerals. 17 is a switching valve, 18 is a pilot I/pressure receiving part of the switching valve 17, and 19 is a shuttle valve.

Next, the configuration of the hydraulic circuit according to the present invention will be described with reference to FIG. Special work For example, a switching valve 17 is provided with an oil passage position A with a throttle part in the hydraulic oil passage that communicates the protective relief valve 4 arranged in the operating circuit of the breaker 2 and the pilot switching valve 8 that controls the breaker 2. was intervened. Here, the throttle part provided at the throttle part equipped oil passage position A of the switching valve 17 may be a variable throttle part so as to be compatible with various special working machines. When the breaker 2 and another hydraulic actuator, such as the packet cylinder 3, are operated in combination, the switching valve 17 is configured to be able to be switched from the open oil passage position to the throttled oil passage position A.

Next, the functions of the hydraulic circuit according to the present invention will be described. When only the breaker 2 is operated independently, the switching valve 17 does not switch, so the hydraulic oil passage of the breaker 2 is in an open oil passage state. When operating the breaker 2 and, for example, the packet cylinder 3 in combination, the operating lever 20 of the remote control valve 9 is operated to the C position or the 2 position. Pressure oil from the pilot pump 14 passes through an oil line 21, a pilot valve 10 or 11, an oil line 22 or 23,
The pilot switching valve 7 is operated to switch. Along with that,
The pilot pressure oil passes through the oil passage 24 and 25, passes through the shaft valve 19, and the oil passage 26, and acts on the pilot pressure receiving portion 18 of the switching valve ]-7. Therefore, the switching valve 17 is switched from the opening oil passage position to the throttle part equipped oil passage position A. As a result, the upstream hydraulic oil passage 2 of the switching valve 17
Since the oil pressure in 7 increases, pressure oil is supplied to the breaker 2 and also to the packet cylinder 3. As described above, when the special work machine breaker 2 and other hydraulic actuators are operated in combination, both can be operated simultaneously without any problem. Note that the switching valve (17) in FIG.
The switching operation may be electrically linked to the operation of 6 (not shown).

FIG. 2 is a main circuit diagram showing a case where a tilting packet 28 is installed as a special working machine. In the figure, two tilting cylinders 30 and 31 of the tilting packet 28 are respectively protective relief valves, and 32 is a switching valve. Since the two tilting cylinders are telescopically operated, a throttle part is provided in each of the hydraulic oil passages in the oil passage position E with a throttle part of the switching valve 32.

The functions when performing a combined operation of the tilting packet 28 and the packet cylinder 3 are the same as in the case of FIG. 1.

Effects of the Invention Special working machines such as breakers and tilting buckets are sometimes attached to the work equipment of a hydraulic excavator to carry out work. The operating circuit of the special working machine is provided with a relief valve for protection against the operation of the special working machine. The relief setting pressure of the protective relief valve is lower than the operating pressure of other hydraulic actuators for boat fishing. In addition, since this protective relief valve is arranged to allow special work equipment to operate without any trouble, the relief set pressure cannot be increased or adjusted.In the conventional hydraulic circuit, for example, by operating a breaker, When multiple operations were performed on the packet cylinders at the same time, the pressure oil flowed preferentially to the breaker due to the high dynamic pressure of the packet cylinders, and the packet cylinders did not operate. This made the multiple operations difficult and caused a problem. .

However, in the hydraulic circuit for complex operation according to the present invention, the hydraulic oil path that communicates the protective relief valve disposed in the operating circuit of the special working machine and the pilot switching valve that controls the special working machine is equipped with an oil restrictor. A switching valve with an oil passage position is provided so that the switching valve can be switched from an open oil passage position to an oil passage position with a throttle part when performing combined operation of the special working machine and another hydraulic actuator. As a result, when the special working machine and another hydraulic actuator are operated in combination, the switching valve is switched to the oil passage position with a throttle portion, and the oil pressure in the hydraulic oil passage on the upstream side of the switching valve increases. Therefore, since pressure oil is sent to the special working machine and other hydraulic actuators, both can be operated simultaneously without any trouble.

Therefore, the construction machine equipped with the hydraulic circuit for combined operation according to the present invention can smoothly perform combined operation of the attached special working machine and other hydraulic actuators, and improves the workability.

[Brief explanation of the drawing]

Fig. 1 is a hydraulic circuit diagram for complex operation of a special working machine according to the present invention, Fig. 2 is a main circuit diagram showing a case where a tilting packet is installed as a special working machine according to this invention, and Fig. 3 is a conventional hydraulic circuit diagram. This is a hydraulic circuit diagram of the technology. 4 30. 7, 8 Breaker (Special work equipment) Packet cylinder protection relief valve Pilot switching valve Remote control valve Main pump Pilot pump switching valve Shuttle valve operation lever Tilting bucket 1~ (Special work equipment) Patent application Representative of Jinyuya Heavy Industries Co., Ltd. Person: Toshiaki Sawara Figure 2

Claims (1)

[Claims] Pilot switching valves for controlling various hydraulic actuators are connected in parallel, and pressurized oil from the main pump can be supplied to each hydraulic actuator via the pilot switching valves by operating the operating lever.In addition, an attachment is attached to the front of the machine. In a construction machine equipped with a special work machine equipped with a hydraulic actuator in its work attachment, and a protective relief valve arranged in the special work machine operating circuit, the above-mentioned protective relief valve,
When performing combined operation of the special work machine and other hydraulic actuators by interposing a switching valve with an oil passage position with a throttle part in the hydraulic oil path that communicates with the pilot switching valve that controls the special work machine, as described above. A hydraulic circuit for complex operation of a special work machine, characterized in that a switching valve is configured to be switchable.