JPH0616140A - Hydraulic structure for working vehicle - Google Patents

Abstract

PURPOSE:To provide a hydraulic structure for a working vehicle by which installation space can be reduced by supplying oil quantity efficiently to a small capacity control valve mechanism requiring a precise flow rate and a large capacity control valve mechanism by means of a small number of apparatuses. CONSTITUTION:A hydraulic structure for a working vehicle is constituted in such a way that pressure oil from a hydraulic pump 14 is divided into a control flow and an excess flow by means of a flow priority valve 27, and the control flow is supplied in series to a power steering control valve mechanism 18 and a raising and lowering link control valve mechanisms 19 and 20, and the excess flow is also flowed together with return oil from the control valve mechanisms 19 and 20, and is supplied to a control valve 28 for a hydraulic motor 24 to a sweeper.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic structure for a work vehicle in which a work device for road cleaning can be mounted on a traveling vehicle body through a link mechanism for changing the posture.

[0002]

2. Description of the Related Art In such a work vehicle, a hydraulic actuator for a working device and a hydraulic actuator for driving a posture changing link mechanism are provided. In general, since the required capacity of each actuator is not the same, each actuator is generally equipped with a hydraulic pump.

[0003]

In the above-mentioned structure, a space for installing the hydraulic pumps is required in order to equip the hydraulic pumps according to the respective required oil amounts, and the installation thereof is required. The space for
There was room for improvement. It is an object of the present invention to provide a hydraulic pump in which the necessary space can be secured and the installation space for these hydraulic devices can be minimized by making a simple change.

[0004]

A characteristic configuration according to the present invention is that a pressure oil from a hydraulic pump is branched into two pressure oils by a shunt valve, and one of the pressure oils is controlled by a control valve mechanism for steering and the link. While supplying in series with the control valve mechanism for the mechanism, the other pressure oil branched by the flow dividing valve and the one pressure oil returned and supplied from the control valve mechanism for the link mechanism are combined. The combined pressure oil is configured to be supplied to the hydraulic motor control valve for the working device, and the operation and effect thereof are as follows.

[0005]

In other words, since the pressure oil from the hydraulic pump requires relatively fine stop control for steering travel and attitude change, it is necessary for steering travel to secure a certain amount of oil. And the control valve mechanism for posture change is diverted by the shunt valve, and the return oil from these and the other pressure oil from the shunt valve are merged, and the merged oil is used as a hydraulic motor for a large-capacity working device. Supply to. Therefore, for a hydraulic motor that requires a large amount of oil, the return oil from the control valve mechanism is used for the hydraulic motor that requires a large amount of oil, while the branch valve supplies the control valve mechanism that requires a certain amount of oil, but a small amount A single hydraulic pump may be provided by merging and supplying the total amount of oil from the hydraulic pump.

[0006]

As a result, even with a single hydraulic pump, a sufficient amount of oil is supplied to the hydraulic motor while supplying a predetermined amount of pressure oil to the control valve mechanism by effectively utilizing the shunt valve. Even if a diversion valve is added, the installation space can be reduced by reducing the number of hydraulic pumps that occupy a larger space than the diversion valve.

[0007]

EXAMPLE As shown in FIG. 4, a front vehicle body 2 having a pair of left and right drive wheels 1 and a rear vehicle body 4 having a pair of left and right drive wheels 3 are swingably connected about a longitudinal axis Y. Then, a steering cylinder 5 is provided between the front and rear vehicle bodies 2 and 4 to form a traveling vehicle body, and the front vehicle body 2 is movably supported by a pair of left and right posture changing link mechanisms 6. A work device 7 for cleaning roads, a lift cylinder 8 and a tilt cylinder 9 for driving them are provided, and an engine 10, a driving seat 11, and a steering handle 12 are provided on the rear vehicle body 4.
And using the wheel loader to construct a road cleaning work vehicle. The work device 7 for cleaning the road will be described. A brush-type sweeper 21 driven by a hydraulic motor 24, a blower 22 for generating a transport wind on a road object scraped up by the sweeper 21, and a blower 22 are carried by a support frame connected to the link mechanism 6. A work device 7 for cleaning the road is configured by attaching a hopper 23 that stores a road item. In the figure, 25 is an opening / closing cylinder that opens / closes the lid 23A of the hopper 23. As shown in FIG. 1, a variable displacement hydraulic pump 1 driven by an engine 10.
3, a work pump 14, a charge pump 15, a variable displacement pump 13 and a variable displacement motor 17 are incorporated into a hydrostatic stepless transmission A to configure a forward-reverse transmission for traveling, and The pressure oil from the pump 14 is divided into a control flow and a surplus flow via a flow priority valve 27 as a flow dividing valve, and one control flow is controlled by the control valve mechanism 1 of the power steering cylinder 5 for steering.
8, the control valve 19 for the lift cylinder 8, the control valve 20 for the tilt cylinder 9, and the control valve 26 of the opening / closing cylinder 25 are supplied in series. The other surplus flow is combined with the return oil from the control valve 26 for the opening / closing cylinder 25 and supplied to the control valve 28 for the hydraulic motor 24 for the sweeper 21. Incidentally, the numerical value is noted, the amount of oil supplied from the work pump 14 is about 80 liters, and this is controlled by the flow priority valve 27 to about 40 liters. As shown in FIG. 2, the engine bonnet 30 is provided behind the driver's seat 11, and the engine 10, the rear blowing fan 31, and the radiator 32 are arranged in the bonnet 30 along the front-rear direction and attached to the radiator 32. As shown in FIG. 3, the fan shroud 33 is divided into upper and lower parts so that it can be removed and cleaned when clogging occurs.

[Other Embodiments] The posture changing link mechanism 6 may be configured to swing right and left. As power steering for driving and steering,
In addition to the fully hydraulic type, a booster type or the like can be used. As a work device for road cleaning, other than the one shown,
It may be provided with a sprinkler or may be used in combination with a horizontally rotating brush.

It should be noted that reference numerals are given in the claims for convenience of comparison with the drawings, but the present invention is not limited to the configurations of the accompanying drawings by the entry.

[Brief description of drawings]

FIG. 1 Hydraulic circuit configuration diagram

FIG. 2 is a vertical sectional side view showing a cooling structure for a radiator.

FIG. 3 is a perspective view showing a fan shroud.

FIG. 4 is a side view showing a road cleaning work vehicle.

[Explanation of symbols]

 2 Traveling vehicle 6 Link mechanism 7 Working device for road cleaning 14 Hydraulic pump 18 Control valve mechanism for steering traveling 19, 20 Control valve mechanism for link mechanism 24 Hydraulic motor 27 Dividing valve 28 Hydraulic motor control valve

Claims (1)

[Claims] 1. A working vehicle in which a working device (7) for cleaning a road can be mounted on a traveling vehicle body (2) through a link mechanism (6) for changing the posture, and a pressure from a hydraulic pump (14). The oil is branched into two pressure oils by a flow dividing valve (27), and one pressure oil is used as a control valve mechanism (18) for steering and traveling and a control valve mechanism (19, 20) for the link mechanism (6). And the other pressure oil branched by the flow dividing valve (27) and the one pressure oil returned and supplied from the control valve mechanism (19, 20) for the link mechanism (6). Is a hydraulic structure of a work vehicle configured to join the above and supply the combined pressure oil to the control valve (28) for the hydraulic motor (24) for the working device (7).