JP4469264B2 - Refraction steering work vehicle - Google Patents

Description

The present invention relates to a refraction steered work vehicle equipped with a work device having a large number of hydraulic actuators.

For example, a wheel loader, which is a typical example of a well-known refractive steering type work vehicle, is connected to a front vehicle body and a rear vehicle body so that the refractive steering can be freely performed around an axis extending vertically. The rear vehicle body is provided with a driver's seat, an engine, a hydraulic power source, a power source, and the like, and the front vehicle body is equipped with various work devices according to work forms.

The equipped working device has a number of hydraulic actuators such as a hydraulic cylinder and a hydraulic motor. Each of the hydraulic actuators is controlled by an operation lever provided in the driver's seat. The operation lever is coupled to a switching spool of a direction switching valve disposed on the front vehicle body and connected to a hydraulic pressure source by a push-pull cable (see, for example, Patent Document 1).

The hydraulic actuator and the pressure oil supply / discharge port of the direction switching valve are connected by a hydraulic pipe. Thus, the direction switching valve is switched by the operation of the operation lever at the driver's seat, and the pressure oil from the hydraulic source is supplied to and discharged from the hydraulic actuator of the work device.

The operation lever and the direction switching valve are installed according to the number of hydraulic actuators included in the working device.
JP-A-9-228423

However, the conventional refraction steerable work vehicle having the above-described configuration has the following problems to be solved in relation to the operation of the hydraulic actuator of the working device.

In accordance with the number of hydraulic actuators of the working device, the plurality of direction switching valves provided on the front vehicle body and the plurality of operation levers provided on the rear vehicle body are respectively connected by push-pull cables. The plurality of push-pull cables are passed through the refractive center portions of the front vehicle body and the rear vehicle body because of the structure of the refractive steering type work vehicle. Therefore, the push-pull cable is easily damaged by the relative bending of the front vehicle body and the rear vehicle body due to the steering of the vehicle body, and by interference between the push-pull cables and adjacent members.

Further, between the direction switching valve provided on the front vehicle body and the working device, there are two hydraulic pipes between each of the plurality of sets of direction switching valves and the hydraulic actuator, that is, between the front vehicle body and the working device. Linked by double number of hydraulic piping. Accordingly, the plurality of hydraulic pipes are easily damaged by interference with the pipes or obstacles. Moreover, it takes up a large installation space and makes the work vehicle look bad.

The present invention has been made in view of the above-mentioned facts, and its technical problem is that the front body and the rear body are refracted to operate a plurality of hydraulic actuators of a working device mounted on the front body. It is an object of the present invention to provide a refraction steered work vehicle that can reduce the number of push-pull cables that pass through the center and hydraulic piping that connects the front vehicle body and the work device.

According to the present invention, as a refractive steering work vehicle that solves the above technical problems, a rear vehicle body provided with a driver's seat, a hydraulic power source and a power source, and the rear vehicle body can freely perform refractive steering around a vertical axis. A directional switching valve connected to the hydraulic power source operated at the driver's seat, a pair of pressure oil connection ports connected to the pair of pressure oil supply / discharge ports of the directional switching valve, and the power source A front vehicle body provided with a plurality of power terminals connected via a switch on the driver's seat, a work device mounted on the front vehicle body with a plurality of hydraulic actuators and an electromagnetic switching valve for pressure oil; A switching spool of the direction switching valve of the front vehicle body and an operation lever of the driver seat of the rear vehicle body are connected by a single push-pull cable, and a pressure oil connection port and a power supply terminal of the front vehicle body are connected to the work device, Electromagnetic by switch operation Refraction characterized by selectively operating a valve to selectively connect a hydraulic oil connection port to a hydraulic actuator, and selectively operating a plurality of hydraulic actuators of a working device by a single direction switching valve. A steerable work vehicle is provided.

According to the refraction steering type work vehicle constructed according to the present invention, a plurality of hydraulic actuators are operated by a single direction switching valve and an electrical switch provided on the vehicle body via a plurality of electromagnetic switching valves provided on the work device. Be controlled. Therefore, it is possible to reduce the number of push-pull cables that pass through the refractive center portions of the front vehicle body and the rear vehicle body, and the hydraulic piping that connects the front vehicle body and the work device.

DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of a refraction steerable work vehicle constructed according to the present invention will be described below with reference to the accompanying drawings illustrating an embodiment of a wheel loader that is a typical example thereof.

The configuration of the present invention will be described with reference to FIG. The wheel loader indicated as a whole by number 2 includes a rear vehicle body 10 provided with a driver's seat 4, a hydraulic power source 6 and a power source 8, and a front vehicle body 10 connected to the rear vehicle body 10 around a vertical axis 12 so as to be able to freely perform refraction steering. A vehicle body 14 is provided. A front wheel device 15 is attached to the front vehicle body 14, and a rear wheel device 11 is attached to the rear vehicle body 10.

The front vehicle body 14 is provided with a lift arm 16 that can freely move up and down, and a working device 18 is attached to the tip of the lift arm 16 via a quick coupler 20 that is a quick attachment / detachment device.

The front vehicle body 14 is also operated by the operation lever 22 of the driver's seat 4 and connected to the hydraulic power source 6 for the working device 18 and a pair of pressure oil supply / discharge ports Y1 of the direction switching valve 24, A pair of pressure oil connection ports A1 and A2 connected to each Y2 and installed at the tip of the lift arm 16, and a plurality of power oils 8 connected to the power source 8 via the switch S of the driver's seat 4 and installed at the tip of the lift arm 16 Power supply terminals B are provided.

The working device 18 includes a hydraulic actuator 26 including a plurality of hydraulic actuators and an electromagnetic switching valve 28 including a plurality of electromagnetic switching valves. The front vehicle body 14 and the work device 18, that is, the pressure oil connection ports A 1 and A 2, and the power supply terminal B and the electromagnetic switching valve 28 are connected by a hydraulic pipe 30 and an electric wiring 32, respectively.

A description will be given with reference to FIG. 2 which is a hydraulic and electric circuit diagram of the working device 18 together with FIG.

The driver's seat 4 includes a seat (not shown), a steering wheel 5, and the operation lever 22 described above. The switch S described above is installed in the vicinity of the steering wheel 5 and includes a pair of on / off switches S1 and S2.

The operation lever 22 is connected to the switching spool of the direction switching valve 24 by a single push-pull cable 23.

The hydraulic pressure source 6 is a hydraulic pressure source that is normally provided in the wheel loader 2, and the directional switching valve 24 is a plurality of directional switching valves (not shown) that are normally provided in the wheel loader 2. This is a well-known valve with three positions and four ports additionally provided. The directional control valve 24 is provided with pressure oil by a pipe 7 provided as a standard and connected to the hydraulic pressure source 6.

The power source 8 is standardly equipped on the wheel loader 2 made of a battery.

The working device 18 in this embodiment includes a hydraulic motor 26a, a hydraulic cylinder 26b, and a hydraulic cylinder 26c as the hydraulic actuator 26.

The electromagnetic switching valve 28 includes two substantially identical two-position 6-port electromagnetic switching valves 28a and 28b.

The pair of inlet-side ports C1 and C2 of the electromagnetic switching valve 28a are connected to the pressure oil connection ports A1 and A2, respectively. The pair of ports D1 and D2 of the four outlet ports are connected to the hydraulic motor 26a, and D3 and D4 are connected to the inlet ports C1 and C2 of the electromagnetic switching valve 28b, respectively. The inlet-side ports C1 and C2 communicate with the ports D1 and D2 when the electromagnetic switching valve 28a is not energized, and communicate with the ports D3 and D4 when energized.

A pair of ports D1 and D2 of the four outlet-side ports of the electromagnetic switching valve 28b are connected to the hydraulic cylinder 26b, and D3 and D4 are connected to the hydraulic cylinder 26c. The inlet side ports C1 and C2 of the electromagnetic switching valve 28b communicate with the hydraulic cylinder 26b when the electromagnetic switching valve 28b is not energized, and the ports D3 and D4 communicate with the hydraulic cylinder 26c when energized. .

The on / off switch S1 is connected to the electromagnetic switching valve 28a via the power supply terminal B1, and the on / off switch S2 is connected to the electromagnetic switching valve 28b via the power supply terminal B2.

(1) Operation of the hydraulic motor 26a:
In order to operate the hydraulic motor 26a of the working device 18, both the on / off switches S1 and S2 are turned off. In this state, the pressure oil from the hydraulic source 6 is supplied to and discharged from the hydraulic motor 26a through the electromagnetic switching valve 28a by operating the direction switching valve 24, and the hydraulic motor 26a can be controlled (state of FIG. 2). .

(2) Operation of the hydraulic cylinder 26b:
To operate the hydraulic cylinder 26b of the working device 18, the on / off switch S1 is turned on and S2 is turned off. In this state, by operating the direction switching valve 24, the pressure oil from the hydraulic source 8 is supplied to and discharged from the hydraulic cylinder 26b via the electromagnetic switching valves 28a and 28b, and the hydraulic cylinder 26b can be controlled.

(3) Operation of the hydraulic cylinder 26c:
In order to operate the hydraulic cylinder 26c of the working device 18, both the on / off switches S1 and S2 are turned on. In this state, the pressure oil from the hydraulic source 8 is supplied to and discharged from the hydraulic cylinder 26c through the electromagnetic valves 28a and 28b by operating the direction switching valve 24, and the hydraulic cylinder 26c can be controlled.

According to the refraction steered work vehicle 2 as described above, the one directional control valve 24 provided in the vehicle body and the electric switches S1 and S2 pass through the two electromagnetic switching valves 28a and 28b of the work device 18. The three hydraulic actuators 26a, 26b, and 26c of the work device 18 are controlled to operate.

Accordingly, it is possible to reduce the number of push-pull cables that pass through the center of refraction of the front vehicle body 14 and the rear vehicle body 10 and the hydraulic piping that connects the front vehicle body 14 and the work device 18.

The present invention has been described in detail based on the embodiments. However, the present invention is not limited to the above-described embodiments, and various changes or modifications can be made within the scope of the present invention.

In the present embodiment, two electromagnetic switching valves 26 (26a, 26b) of the working device 18 are provided. However, by increasing the number of electromagnetic switching valves and the number of switches for operating the electromagnetic switching valves 26, one direction is provided. More hydraulic actuators can be operated by the switching valve 24.

Alternatively, by increasing the number of directional control valves 24, each of the directional control valves can operate a plurality of hydraulic actuators, that is, more hydraulic actuators.

The present invention has been described in detail based on the embodiments. However, the present invention is not limited to the above-described embodiments, and various changes or modifications can be made within the scope of the present invention, for example, as described below. Is.

Although the switch S is installed in the vicinity of the steering wheel 5 in the embodiment of the present invention, it may be installed in the grip portion of the operation lever 22. When the switch operation is frequent, the operation can be made easier. Furthermore, operability can be further improved by using a plurality of switches as rotary switches.

In place of the push-pull cable 23 and the direction switching valve 24 in the embodiment of the present invention, an electric operating device that outputs an electric signal in response to the operation of the operating lever 22 and an electromagnetic proportional switching valve, an electric operating device via a controller. May be connected to the electromagnetic proportional switching valve through the wiring harness (electric wire) between the refractive center of the front vehicle body and the rear vehicle body.

BRIEF DESCRIPTION OF THE DRAWINGS The schematic explanatory drawing of the structure which showed the refractive steering type work vehicle of this invention with the wheel loader which is a typical example. FIG. 2 is a hydraulic and electric circuit diagram of the working device of the wheel loader shown in FIG. 1.

Explanation of symbols

2: Wheel loader (refractive steering work vehicle)
4: Driver's seat 6: Hydraulic source 8: Power source 10: Rear vehicle body 12: Vertical axis 14: Front vehicle body 18: Work device 26 (26a, 26b, 26c): Hydraulic actuator 28 (28a, 28b): Electromagnetic switching valve A ( A1, A2): Pressure oil connection port B (B1, B2): Power supply terminal S (S1, S2): Switch Y1, Y2: Pressure oil supply / discharge port

Claims (1)

After the driver's seat, hydraulic power source and power supply are installed,
After that, a refracting steering is freely connected to the vehicle body around the vertical axis, and is connected to the directional control valve connected to the hydraulic pressure source operated at the driver's seat, and a pair of pressure oil supply / discharge ports of the directional switching valve. A pair of connected pressure oil connection ports, and a front vehicle body provided with a plurality of power supply terminals connected to the power supply via a switch on the driver's seat;
A working device mounted on the front vehicle body with a plurality of hydraulic actuators and an electromagnetic switching valve for pressure oil,
The switching spool of the direction switching valve of the front vehicle body and the operation lever of the driver seat of the rear vehicle body are connected by a single push-pull cable.
Connect the pressure oil connection port of the front car body and the power terminal to the work equipment,
By selectively operating the electromagnetic switching valve by operating the switch, the pressure oil connection port is selectively connected to the hydraulic actuator,
A refraction steering work vehicle characterized in that a plurality of hydraulic actuators of a work device are selectively operated by a single direction switching valve.

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