JPH0430037A - Working device operating structure for working vehicle - Google Patents

Abstract

PURPOSE:To facilitate maintenance and inspection work of hydraulic equipments by switching a control valve of a working device operating hydraulic cylinder with pilot valves, and driving a hydraulic pump against the pilot valves with an electric motor. CONSTITUTION:A boom cylinder 13 is operated for expansion and shrinkage with a main pump SP to be driven by an engine 3, and a control valve 16 is switched with two pilot valves 18, 18 to be operated by an operating lever 17. An auxiliary pump HP against the pilot valves 18, 18 is prepared to be driven by an electric motor M. A pressure sensor 21 is provided in the discharge side oil passage 20 of the auxiliary pump PH, and also a control device 23 is provided for operating a variable resistor 22 to reduce the rotating speed of the motor M when a detected pressure value of the pressure sensor 21 coincides with a preset value. The auxiliary pump HP is driven by the electric motor M.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a structure for operating a hydraulically driven working device installed on a working vehicle such as a backhoe or a wheel loader.

[Conventional technology]

In the working equipment operation structure of this type of work vehicle, as shown in Fig. 3, the control valve (V) of the working equipment driving hydraulic cylinder (13) can be switched and operated by a pilot valve (PV) with good operability. Generally, a hydraulic pump (IIP) is provided for the pilot valve (PV), and the hydraulic pump (HP) is driven by an engine (3) mounted on the work vehicle.

In this case, while the engine (3) is running, the pilot valve (PV) is operated by its operating lever (17).
Since it is always activated by operating, for example,
If an operator of a backhoe gets out of the backhoe with the engine still running and his or her body accidentally touches the control lever, there is a risk that the excavation equipment will be in an unexpected operating state. Therefore, in order to prevent this possibility, a switch valve (SV) is provided in the oil path to the pilot valve (PV) to provide an interlock mechanism that allows selection of whether or not to operate the pilot.

[Problem to be solved by the invention]

However, the conventional technology described above requires a separate operating mechanism for the switch valve, which tends to complicate the hydraulic circuit structure as a whole, and the control valve must be switched and operated in order to allow the work equipment to fall by gravity after the engine is stopped. Since it is not possible to do so, there is the inconvenience of having to restart the engine in order to bring the work equipment into contact with the ground for safety reasons.

The present invention aims to eliminate the above-mentioned disadvantages.

[Means to solve the problem]

In order to achieve the above object, the present invention configures a control valve of a hydraulic cylinder for driving a working device to be switchable with a pyro valve, provides a hydraulic pump for the pyro valve, and also provides an electric pump for the hydraulic cylinder. It is characterized by being configured so that it can be driven by a motor.

[For production]

According to the above configuration, the hydraulic pump for the pilot valve is driven by an electric motor that is separate from the engine mounted on the work vehicle. Since the pump can be driven and stopped freely, stopping the electric motor while the engine is running prevents the pilot valve from being accidentally activated, eliminating the need for a switch valve, which was previously required. Can be omitted.

In addition, since the electric motor can be rotated by the battery even when the O engine is stopped, for safety reasons, after the engine has stopped, the control valve can be switched to allow the work equipment floating in the air to fall by gravity. This can be done without requiring starting. In addition, if this is used, it is possible to perform drive switching operations to check and confirm whether or not there is oil leakage from the pilot valve or control valve without turning the engine.

〔Effect of the invention〕

Therefore, by a relatively simple modification of just installing an electric motor and its on/off switch, the hydraulic circuit structure could be simplified due to the action of This is a practical and convenient operation in that the work equipment can be dropped by gravity after the engine has stopped, and it also has the advantage of being able to perform maintenance and inspection work on hydraulic equipment in conditions that were previously impossible. was able to occur.

(Example〕 Embodiments of the present invention will be described below based on the drawings.

FIG. 2 shows a full swing type hackhoe, which is an example of a working vehicle according to the present invention. This backhoe has a swivel platform (2
) is mounted so that it can rotate freely, the engine (3) and the control section (4) are placed on the swivel table (2), and the excavation work equipment (5) is connected to it. At the front of the aircraft, there is a dozer device (
7) are connected.

The excavation work equipment (5) includes swingable booms (8).
), an arm (9), and a packet (10), which can be freely retracted and swung around the vertical axis by a swing cylinder (11).
2) is connected. Further, the excavation work is performed by telescopic hydraulic drive of the boom cylinder (13), arm cylinder (14), and Hakent cylinder (15).

In this backhoe, the control valve (V) of the hydraulic cylinder for driving the excavation work equipment is configured to be switchable with a pilot valve (PV), and a hydraulic pump (HP) is provided for the pilot valve (PV). The pump (HP) is configured to be drivable by an electric motor (M), and its operation structure will be explained in the case of a boom cylinder (13).

As shown in Figure 1, the boom cylinder (13) is telescopically operated by the main pump (SP) driven by the engine (3), and its control valve (16) is operated by two control valves (17). pilot valve (18).

The configuration is such that the switching operation is performed in (18).

A dedicated sub pump (HP) is provided for the pilot valves (1B) and (1B), and this sub pump (HP) is driven by an electric motor (M). This motor (M) is driven and rotated by a battery (B) that is charged by a dynamo (D) while the engine is rotating, and a switch (
19) is provided.

In addition, the discharge side oil passage (20) of the auxiliary pump (HP) is equipped with a pressure sensor (21) for detecting oil pressure, and
A variable resistor (22) is provided to change and adjust the rotational speed of the electric motor (M), and when the detected pressure value of the sensor (21) reaches a preset value, the variable resistor (2
A control device (23) is provided which operates the motor (2) to reduce the rotational speed of the motor (M) by a predetermined degree.

In other words, during excavation work, the engine (3), electric motor (M
) If the boom cylinder (13) is not used continuously while both are being driven, the pilot pulp (18),
The oil passage (20) in (1B) continues to operate and the oil temperature rises, but if the pressure sensor (21) is set appropriately, the discharge amount of the sub pump (HP) will be automatically lowered and the oil temperature will rise. The phenomenon can be suppressed.

Furthermore, by keeping the electric motor (M) running even when the engine (3) is stopped, the control valve (16) can be switched by operating the control lever (17), and the boom (8) can be lowered by gravity.

The operation lever (17) is configured as a cross operation lever that also operates the pilot valve (not shown) of the hydraulic cylinder (15) of the packet (10), and the cross operation between the arm (9) (not shown) and the swing. The working device (5) is configured to be operated by two cross-operated levers.

[Another example]

Pressure sensor (21), variable resistor (22) in Figure 1
), a hydraulic circuit may be used in which the control device (23) is omitted.

Incidentally, although reference numerals are written in the claims section for convenient comparison with the drawings, the present invention is not limited to the structure shown in the accompanying drawings.

[Brief explanation of drawings]

The drawings show an embodiment of the working device operating structure for a working vehicle according to the present invention, FIG. 1 is a hydraulic circuit diagram of the structure, FIG. 2 is a side view of a backhoe, and FIG. 3 is a conventional example of the hydraulic circuit. It is a diagram. (V)...Control valve, (PV)...Pyront hull, (HP)...Pump, (M)...Electric motor.

Claims (1)

[Claims] The control valve (V) of the hydraulic cylinder for driving the work equipment is configured to be switchable with a pilot valve (PV), and a hydraulic pump (HP) is provided for the pilot valve (PV). Electric motor (
A working device operating structure for a working vehicle configured to be driven by M).