JP3130134B2 - Self-propelled work vehicle - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a self-propelled work vehicle such as a wheel crane or excavator.

[0002]

2. Description of the Related Art Generally, a self-propelled work vehicle such as a wheel crane turns on a traveling vehicle body which travels by front wheels disposed on the left and right front sides of a vehicle body and rear wheels disposed on the left and right rear sides of the vehicle body. The table is provided so as to be pivotable, and working equipment such as a crane device and an operator's cab are installed on the table.

[0003] Such a self-propelled work vehicle has a front-wheel steering hydraulic cylinder for changing the direction of the front wheel to the left and right and a rear wheel, as disclosed in Japanese Patent Publication No. 63-61233, for example. A rear wheel steering hydraulic cylinder for changing the direction to the left and right is provided, so that not only the front wheels but also the rear wheels can be steered.

[0004]

In the self-propelled work vehicle disclosed in the above-mentioned publication, the steering of the front wheels and the steering of the rear wheels are performed only by a front wheel steering handle as a front wheel steering operation element. For example, when switching from front wheel steering to front and rear wheel simultaneous steering in the middle of a turn, the rear wheel cannot be steered as large as the front wheel, and You may get stuck.

In order to solve such a problem, a switching valve having three switching positions is provided in a hydraulic line connecting the rear wheel steering hydraulic cylinder and the hydraulic pump.
There has been proposed a self-propelled work vehicle in which the switching valve is switched by an operator provided in a driver's cab so that the rear wheels are steered by a hydraulic system independent of the front wheels.

[0006] However, such a self-propelled working vehicle is
Since the front wheel steering system and the rear wheel steering system are independent of each other, when traveling with the turntable turned 180 degrees, the steering wheel for the front wheels must be used to steer the rear wheels. There was a problem that could not be done.

SUMMARY OF THE INVENTION The present invention has been made in view of such circumstances, and has as its object to steer the rear wheels with a front wheel steering operation device when the vehicle is running with the turntable turned 180 degrees. It is an object of the present invention to provide a self-propelled work vehicle capable of carrying out the work.

[0008]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention is directed to a traveling vehicle body that travels with front wheels and rear wheels disposed on both left and right sides of the vehicle body, and turns the front wheels left and right. And a hydraulic cylinder connected to the front-wheel steering hydraulic cylinder through a front-wheel left-turn hydraulic pipeline and a front-wheel right-turn hydraulic pipeline, and supplied to the front-wheel steering hydraulic cylinder. A front wheel steering hydraulic control means for controlling the vehicle, a driver's cab provided on the traveling vehicle body via a turntable, and a front wheel steering hydraulic control means provided in the driver's cab to operate the front wheel steering. A front-wheel steering operator for operating a steering hydraulic cylinder, a rear-wheel steering hydraulic cylinder for turning the rear wheel in the left-right direction, and a rear-wheel left-turn hydraulic pressure for the rear-wheel steering hydraulic cylinder. Via the pipeline and the hydraulic pipeline for the right turn of the rear wheel A rear-wheel steering hydraulic control means for controlling the hydraulic pressure supplied to the rear-wheel steering hydraulic cylinder, and a rear-wheel steering hydraulic control means provided in the driver's cab to operate the rear wheel A rear wheel steering operating element for operating a steering hydraulic cylinder, and a hydraulic pressure supplied from the front wheel steering hydraulic control means to the front wheel steering hydraulic cylinder is supplied to the rear wheel steering hydraulic cylinder. Hydraulic line switching means for switching the hydraulic line as described above.

[0009]

By adopting such a configuration, the present invention provides a hydraulic control system in which the hydraulic oil introduced into the front wheel steering hydraulic cylinder from the front wheel steering hydraulic control means is introduced into the rear wheel steering hydraulic cylinder. Therefore, it is possible to steer the rear wheels with the front wheel steering operator.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS.

FIG. 1 is a side view of a self-propelled work vehicle according to an embodiment of the present invention. In FIG. 1, reference numeral 1 denotes a traveling body of the self-propelled work vehicle. The traveling vehicle body 1 travels by front wheels 3, 3 disposed on the left and right front sides of the vehicle body 2 and rear wheels 4, 4 disposed on the left and right rear sides of the vehicle body 2.
A swivel 5 is provided at the upper center of the table. The revolving base 5 is configured to be revolved by a hydraulic motor (not shown), and a crane device 6 and a dual-purpose cab 7 are provided on an upper surface thereof. Outriggers 8 are provided on the left, right, front and rear of the vehicle body 2 to support the vehicle body 2 during crane work.

FIG. 2 is a diagram showing a steering system of the self-propelled work vehicle shown in FIG. 1. In FIG. 2, reference numeral 10 denotes a front wheel steering hydraulic pump. The front-wheel steering hydraulic pump 10 is driven by an engine (not shown) mounted on the vehicle body 2, and hydraulic oil discharged from the front-wheel steering hydraulic pump 10 is supplied to a hydraulic pipeline. The power is supplied to a front-wheel steering hydraulic control unit (orbit roll) 12 through a motor 11.

The hydraulic control unit 12 for steering the front wheels includes:
A front wheel steering handle 13 as a front wheel steering operator provided in the cab 7 is operated via a steering shaft 13a. For example, when the front wheel steering handle 13 is turned to the right, the front wheel steering is performed. Hydraulic pump 10 to front wheel steering hydraulic control unit 1
2 is supplied to the front-wheel steering hydraulic cylinders 15R and 15L through the front-wheel right-turn hydraulic pipeline 14a, and conversely, when the front-wheel steering handle 13 is turned to the left, the front-wheel steering Hydraulic oil supplied from the hydraulic pump 10 to the front wheel steering hydraulic control unit 12 passes through the front wheel left turn hydraulic pipeline 14b, and the front wheel steering hydraulic cylinders 15R, 15R.
5L is supplied.

The front wheel steering hydraulic cylinders 15R, 15R
L is for turning the left and right front wheels 3 and 3 left and right, for example, hydraulic oil from the front wheel steering hydraulic control unit 12 is introduced into each of the cylinders 15R and 15L through the front wheel right turning hydraulic pipeline 14a. Then, the front wheels 3 and 3 extend and contract to rotate rightward, and hydraulic oil from the front wheel steering hydraulic control unit 12 passes through the front wheel left rotation hydraulic pipeline 14b to each of the cylinders 15R and 15L. When introduced, the front wheels 3 and 3 extend and contract to rotate to the left. An oil drain pipe 16 is connected to the front wheel steering hydraulic control unit 12, and the front wheel steering hydraulic cylinder 1
The hydraulic oil extruded from the 5R and 15L is discharged to the oil reservoir 17 through the oil drain pipe 16.

In FIG. 2, reference numerals 18R and 18L denote rear-wheel steering hydraulic cylinders for turning the rear wheels 4 and 4 in the left-right direction. These rear wheel steering hydraulic cylinders 18R,
18L is adapted to expand and contract with hydraulic oil supplied from the rear wheel right-turn hydraulic line 19a or the rear wheel left-turn hydraulic line 19b, for example, from the rear wheel right-turn hydraulic line 19a. When oil is supplied, the rear-wheel steering hydraulic cylinders 18R and 18L extend and contract to rotate the rear wheels 4 and 4 rightward, and conversely, the rear-wheel left-turn hydraulic pipeline 1
When hydraulic oil is supplied from 9b, the rear-wheel steering hydraulic cylinders 18R, 18L extend and contract to rotate the rear wheels 4, 4 to the left.

The hydraulic line 19a for turning the rear wheel right and the hydraulic line 19b for turning the rear wheel left are 6-port, 3-position switching as rear wheel steering control means for controlling the steering direction of the rear wheels 4, 4. The rear port steering hydraulic pump, which is driven by an engine (not shown) like the front wheel steering hydraulic pump 10, is connected to the outlet port of the valve 20. 22 is connected via a hydraulic line 21 and the hydraulic cylinder 18 for steering the rear wheels.
An oil drain line 23 for returning hydraulic oil from the R and 18L to the oil reservoir 17 is connected.

The 6 port 3 position switching valve 20 is
From the electromagnetic switching valves 24a and 24b to the pilot line 25
When the pilot pressure from the solenoid-operated switching valve 24a is introduced into the pilot port of the 6-port 3-position switching valve 20, the 6-port 3-position switching is performed. Valve 20
2 moves upward in FIG. 2, whereby hydraulic oil from the rear-wheel steering hydraulic pump 22 passes through the rear-wheel left-turn hydraulic line 19b, and the rear-wheel steering hydraulic cylinder. 1
8R and 18L. Conversely, when the pilot pressure from the electromagnetic switching valve 24b is introduced into the pilot port of the 6-port 3-position switching valve 20,
The spool (not shown) of the 6-port 3-position switching valve 20 moves downward in FIG.
2 is supplied to the rear-wheel steering hydraulic cylinders 18R and 18L through the rear-wheel right-turn hydraulic pipeline 19a. In addition, the inlet ports of the electromagnetic switching valves 24 a and 24 b are connected to the hydraulic line 11 via a parrot pressure introducing line 26.

The solenoids of the electromagnetic switching valves 24a and 24b are operated by a stick-type operation switch 27 provided in the cab 7. For example, when the operation switch 27 is tilted rightward from the neutral position, When the electromagnetic switching valve 24a is operated, and when the operation switch 27 is turned to the left from the neutral position, the electromagnetic switching valve 24b is operated.

Downstream of the front wheel steering hydraulic control unit 12, as shown in FIG. 2, a switching device 2 for switching the front wheel steering handle 13 for rear wheel steering.
8 are provided. The pipeline switching device 28 is provided with the hydraulic pipeline 14a for turning the front wheel right or the hydraulic pipeline 1 for rotating the front wheel left.
In order to introduce the hydraulic oil supplied from 4b to the front wheel steering hydraulic cylinders 15R and 15L to the rear wheel steering hydraulic cylinders 18R and 18L, the front wheel right turn hydraulic line 14a
A 4-port 2-position electromagnetic switching valve 29 for switching between a hydraulic line 19a for turning the rear wheel right and a hydraulic line 14b for turning the front wheel left and a hydraulic line 19b for turning the rear wheel left, and a downstream side of the electromagnetic switching valve 29. Hydraulic line 19a for turning right rear wheel
And reversely switch the hydraulic line 19b for turning the rear left wheel 2
It is constituted by a port 2 position electromagnetic switching valve 30 and is operated by an ON signal from a switching switch 31 provided in the cab 7.

The self-propelled work vehicle constructed as described above turns on the changeover switch 31 provided in the cab 7 when the turntable 5 is turned with the turntable 180 degrees, and is turned to the 4-port 2-position. Electromagnetic switching valve 29 and 2-port 2
The position electromagnetic switching valve 30 performs a switching operation as shown in FIG. As a result, the hydraulic oil supplied from the front-wheel steering hydraulic control unit 12 to the front-wheel steering hydraulic pipeline 14a is supplied to the four-port two-position electromagnetic switching valve 29 and the rear-wheel right-turn hydraulic pipeline 19.
a, through the 2-port 2-position electromagnetic switching valve 30 and the rear-wheel left-turn hydraulic line 19b, to the rear-wheel hydraulic cylinder 18R.
And 18L, the rear wheels 3, 3 can be steered by the front wheel steering handle 13.

In the above embodiment, the pipeline switching device 28
Is constituted by a four-port two-position electromagnetic switching valve 29 and a two-port two-position electromagnetic switching valve 30, but even if a switching valve 32 as shown in FIG. The hydraulic oil supplied from the hydraulic line 14b to the front wheel steering hydraulic cylinders 15R and 15L can be introduced into the rear wheel steering hydraulic cylinders 18R and 18L. Therefore, in the second embodiment shown in FIG. 4, the configuration of the pipeline switching device 28 can be simplified.

In the above-described embodiment, the electromagnetic switching valve 2
Although the changeover switches 9 and 30 are operated by the changeover switch 31 provided in the cab 7, for example, when the turntable 5 turns 180 degrees from the home position shown in FIG.
9, 9 may be automatically operated.

[0023]

As described above, according to the present invention, the hydraulic pipe is provided so that the hydraulic pressure supplied from the front wheel steering hydraulic control means to the front wheel steering hydraulic cylinder is supplied to the rear wheel steering hydraulic cylinder. A self-propelled work vehicle capable of steering a rear wheel with a front-wheel steering operator when traveling with a turntable turned 180 degrees by providing a hydraulic pipeline switching means for switching a road. Can be provided.

[Brief description of the drawings]

FIG. 1 is a side view of a self-propelled work vehicle according to one embodiment of the present invention.

FIG. 2 is a diagram showing a steering system of the self-propelled work vehicle shown in FIG.

FIG. 3 is an operation explanatory view of the pipeline switching device shown in FIG. 2;

FIG. 4 is a diagram showing a steering system of a self-propelled work vehicle according to another embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Running vehicle body, 2 ... Body, 3 ... Front wheel, 4 ... Rear wheel, 5 ... Turning table, 6 ... Crane device, 7 ... Operating room, 10 ... Front wheel steering hydraulic pump, 12 ... Front wheel steering hydraulic control Unit, 1
3 ... front wheel steering handle, 15R, 15L ... front wheel steering hydraulic cylinder, 18R, 18L ... rear wheel steering hydraulic cylinder, 20 ... 6 port 3 position switching valve, 22 ... rear wheel steering hydraulic pump, 27 ... Operation switches (rear wheel steering operation elements), 28... Pipeline switching device, 31.

Claims (1)

(57) [Claims] 1. A traveling vehicle body driven by front wheels and rear wheels disposed on both left and right sides of a vehicle body, a front wheel steering hydraulic cylinder for turning the front wheels left and right, and a front wheel steering hydraulic pressure. A front-wheel steering hydraulic control means connected to a cylinder via a front-wheel left-turn hydraulic pipeline and a front-wheel right-turn hydraulic pipeline to control hydraulic pressure supplied to the front-wheel steering hydraulic cylinder; A driver's cab provided above via a swivel, and a front-wheel steering operator provided in the driver's cab to operate the front-wheel steering hydraulic control means to operate the front-wheel steering hydraulic cylinder; A rear-wheel steering hydraulic cylinder for turning the direction of the rear wheel left and right, and connected to the rear-wheel steering hydraulic cylinder via a rear-wheel left-turn hydraulic line and a rear-wheel right-turn hydraulic line. And the hydraulic pressure supplied to the rear-wheel steering hydraulic cylinder Rear-wheel steering hydraulic control means for controlling the rear-wheel steering hydraulic cylinder provided in the driver's cab and operating the rear-wheel steering hydraulic cylinder And hydraulic line switching means for switching a hydraulic line so as to supply the hydraulic pressure supplied from the front wheel steering hydraulic control means to the front wheel steering hydraulic cylinder to the rear wheel steering hydraulic cylinder. Self-propelled work vehicle.