JPS5938538Y2 - Hydraulic circuit of backhoe with crane function - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a hydraulic circuit for a backhoe having a crane function.

When a crane attachment is attached to a backhoe,
Conventional backhoe hydraulic circuits cannot ensure crane functionality and safety.

The present invention was developed in consideration of the above, and includes a backhoe equipped with a counterbalance valve and a shuttle valve in addition to a hydraulic motor for a winch, as well as an operation valve and a safety valve for operating the same. , boom again,
The present invention aims to provide a hydraulic circuit for a backhoe having a crane function, which is configured by attaching a pilot check valve to each of the arm cylinder circuits so that the backhoe can obtain a crane function with excellent safety. be.

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

In the figure, 1 and 2 are left and right traveling motor devices, 3 and 4 are hydraulic motors thereof, and 5 and 6 are brake devices.

7.8 are two hydraulic pumps, and 9 and 10 are left and right steering switching valves.

11 is a boom cylinder, 12 is an arm cylinder, 13 is a packet cylinder, 14 is a boom operation valve, 15 is an arm operation valve, and 16 is a packet operation valve, and by operating these, the hydraulic pump 7.8 is connected to each cylinder. The pressure oil is controlled so that each cylinder expands and contracts.

17 is a swing motor device, 18 is a brake valve, and 19
is a swing operation valve.

20 is a hydraulic motor for the winch, and 21 is a winch operation valve for operating the hydraulic motor 20, which is connected in parallel with each of the above-mentioned operation valves.

22 is a counterbalance valve, and 23 is a shuttle valve, which are interposed in a hydraulic circuit for the winch that connects the hydraulic motor 20 and the winch operation valve 21.

24 is a shaft brake.

A safety valve 25 and a load meter 26 are provided in the raising circuit of the hydraulic circuit for this winch.

In addition, the boom cylinder 11 and the arm cylinder 12
A pilot check valve 27 is installed in each lifting circuit.
．． 28 is interposed therein, and a variable throttle valve 29 is interposed in the lowering circuit of the boom cylinder 11.

The winch hydraulic motor 20 is mounted on a crane drum mounted on a boom.

In the above configuration, by operating the winch operation valve 21, the hydraulic motor 20 is rotated in the forward and reverse directions, and the winch is raised and lowered.

At this time, if an abnormal load is applied to the winch during the ascent, the safety valve 25 is activated to prevent abnormal pressure from being generated in the winch hydraulic circuit.

At this time, an abnormal load also acts on the boom and arm that support the winch, and abnormal pressure is generated in the lifting circuit of the boom cylinder 11 and arm cylinder 12.
If the hoses of both cylinders are damaged due to this abnormal pressure, the pilot check valves 27 and 28 are activated to prevent the boom and arm from falling.

On the other hand, in the hydraulic circuit configured as described above, by operating the boom operation valve 14 and the arm operation valve 15, the boom cylinder 1 is
1 and arm cylinder 12 are extended and contracted.

That is, with each operating valve 14, 15 in the lowered position, each cylinder 11. When pressure oil is sent to the lowering side circuit of No. 12, the pressure in the lowering circuit at this time acts as pilot pressure on the pilot check valve 2728 in the raising circuit, which opens, and the lowering circuit at this time acts on the pilot check valve 2728 in the raising circuit. is opened and each cylinder 11, 12 performs a lowering operation.

Also, when each operating valve 14.15 is set to the raised position and pressure oil is sent to the raised side circuit of each cylinder 11.12, this pressure oil pushes open the pilot check valve 27.28, and Enter the chamber on the raised side and each cylinder 11. 12 performs a raising operation.

Further, when abnormal pressure acts on the raising side chamber of each cylinder 11, 12, a relief valve connected to each raising circuit operates to relieve the pressure oil at this time.

The present invention is as described above, and in a hydraulic circuit of a backhoe having actuators for work equipment such as a boom cylinder 11, an arm cylinder 12, and a packet cylinder 13, in addition to the hydraulic circuit for each of the actuators described above, a winch installed in the backhoe is used. Hydraulic motor 20 and hydraulic pump 7.
8 and each operating valve 9, 10 for each of the above actuators is installed on the way.
A winch hydraulic circuit is provided which is connected to the winch operating valve 21 in parallel with the boom cylinder 11, and the winch hydraulic circuit is equipped with a counterbalance valve 22, a shuttle valve 23, and a safety valve 25. Pilot check valves 27 and 28 are installed in the raising circuits of the hydraulic circuits for the boom and arm cylinders 12 to prevent the flow of oil in the direction in which the boom and arm descend. Since the hydraulic circuit of the backhoe is constructed by connecting and inserting it into the lowering circuit side of .12, it is possible to obtain a crane function that is safer than the conventional hydraulic circuit of a backhoe.

[Brief explanation of the drawing]

The drawing is a hydraulic circuit diagram showing an embodiment of the present invention. 7.8 is a hydraulic pump, 11 is a boom cylinder, 12 is an arm cylinder, 13 is a packet cylinder, 20 is a hydraulic motor, 21 is a winch operation valve, 22 is a counter balance valve, 23 is a shuttle valve, 27.28 is a pilot check valve.

Claims (1)

[Scope of utility model registration request] Boom cylinder 11. In the hydraulic circuit of a backhoe having actuators for working machines such as the arm cylinder 12 and the packet cylinder 13, in addition to the hydraulic circuit for each actuator described above, there is also a winch hydraulic motor 20 and a hydraulic pump 7.8 provided in the backhoe. A winch hydraulic circuit is provided in which the winch operating valve 21 is connected in parallel with the operating valves 9 and 10 for each of the actuators.
A counterbalance valve 22, a shuttle valve 23, and a safety valve 25 are installed in the winch hydraulic circuit, and the boom and arm are placed in the lifting circuit for the boom cylinder 11 and arm cylinder 12 in the direction in which the boom and arm descend. A pilot check valve 27,28 is connected to each pilot port of each cylinder 11.
A hydraulic circuit for a backhoe having a crane function, characterized in that the hydraulic circuit is connected to and charged to the lowering circuit side of No. 12.