JPS6116668B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides fluid from a pair of fluid pressure pumps that separately supply fluid to the forward and reverse reversible drive fluid pressure motors of the left and right crawlers when they are traveling in a straight line.
In each of the spin turn in which the left and right crawlers are rotated in opposite directions and the pivot turn in which only one of the left and right crawlers is rotated, the engine horsepower for driving the pump is efficiently supplied to the pair of fluid pressure motors. It is an object of the present invention to provide a steering device for a moving vehicle that can be used to make safe and efficient turns while using the vehicle.

When the aircraft turns, compared to when the aircraft is moving straight, the lateral parts of the left and right crawlers that change direction push the mud laterally, so a large amount of engine horsepower is required. This is noticeable in soft ground that sinks deep into the earth. In order to improve straight-line performance, fluid pressure motors for driving the left and right crawlers are supplied with fluid from a pair of fluid-pressure pumps separately when the vehicle is traveling straight. Conventionally, in order to supply fluid from a fluid pressure pump to a pair of fluid pressure motors, the fluid was supplied to the motors so that the motor drive speed was the same in both spin turns and pivot turns. In other words, the amount of fluid supplied to each fluid pressure motor in the driving state is the same whether it is a spin turn or a pivot turn, but in this case, in either the spin turn or the pivot turn, the following There were the following inconveniences.

In other words, according to the conventional structure, a spin turn in which a pair of motors are driven together requires more engine horsepower than a pivot turn in which only one motor is driven. If the horsepower is set to the required horsepower, an excessive load will be applied to the engine during a spin turn, causing the engine to stop.On the other hand, setting the engine horsepower to the horsepower required for a spin turn will cause the inconvenience. In this case, the engine horsepower cannot be used to the maximum effect when making a pivot turn, and in this case, if the turning speed during a spin turn is set to a safe speed, the turning speed during a pivot turn will become unreasonably slow. Conversely, if the turning speed during a pivot turn is set to a safe speed, there is a problem that the turning speed during a spin turn may become unduly fast, resulting in a dangerous situation.

The present invention has been made with the above-mentioned circumstances in mind, and includes a pair of fluid pressure pumps, a pair of fluid pressure motors capable of forward and reverse rotation for driving left and right crawlers separately, and A state in which the fluid from the fluid pressure pump side channel is supplied to each fluid pressure motor separately to drive both fluid pressure motors to rotate in the same direction, and a state in which the fluid pressure motors are driven to rotate in opposite directions. In this case, the fluid from one pump-side flow path is supplied to one fluid-pressure motor, and the fluid from the other pump-side flow path is returned to the tank-side flow path. a directional switching valve that can freely switch the direction of fluid supply from the fluid pressure pump side passage to the fluid pressure motor; There are two types of flow paths: one in which fluid from one fluid pressure pump is supplied only to one directional valve side, and the other in which fluid from one fluid pressure pump is returned to the tank side flow path and connected to the other fluid pressure pump. The structure is characterized by the provision of switching valves that can be switched between supplying fluid from the two-way switching valves in parallel to each of the two-way switching valves, and this structure provides the following effects.

That is, fluid from a pair of hydraulic pumps is
By operating the bidirectional switching valve and the switching valve provided in the flow path from the fluid pressure pump to the directional switching valve, the total amount of fluid supplied to both motors in the spin turn and one motor driven in the pivot turn are determined. The difference between the amount of fluid supplied to the motor and the amount of fluid supplied to the motor is much smaller than that of the conventional method, which simply switches between driving both motors or driving one motor. from,
In other words, while a pair of pumps drives each motor separately when traveling straight, during a spin turn, only the fluid from one of the pumps is transferred to both motors by operating the switching valve. During a pivot turn, only the fluid from one of the pumps is supplied to one motor, so the engine load for driving the pump during the spin turn and the engine load for driving the pump during the pivot turn are reduced. While making the load almost the same, avoiding sudden turns during spin turns or unduly slow turns during pivot turns, and making the turning speed during pivot turns and the turning speed during spin turns almost the same, With one pump, the vehicle can turn more slowly than when traveling straight ahead, making it possible to make safe and efficient turns while making the most effective use of the horsepower of the pump-driving engine. Eventually, a steering system for work vehicles with great practical advantages was obtained.

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

FIG. 1 shows a side view of a combine harvester as an example of a working vehicle, and shows a pair of left and right running crawlers 1a, 1.
b. This machine is equipped with a threshing device 3 that handles and threshes grain culms while holding and conveying them with a feed chain 2 built on one side, a driver's seat 4, an engine 5 for driving various devices, etc. At the front, there is a device 6 for pulling up grain culms planted in the field, a reaping device 7 for cutting the base of the raised grain culms, and a rear conveyor for conveying the harvested grain culms to the rear and delivering them to the threshing device 3. A reaping processing section consisting of a device 8 and the like is connected and equipped. As the machine progresses, the grain culms planted in the field are lifted up and harvested, and the harvested grain culms are threshed in a continuous manner.

Reference numeral 9 in the figure is a grain culm guide rod that guides the uncut grain culm located on the left lateral side of the machine body while pressing it outward to the left side, and is vertically swung around the axis X in the longitudinal direction. The structure is configured such that the grain culm guide position protrudes outward on the left side of the machine body and a retracted position close to the left side wall of the machine body.As shown in FIG. The threshing clutch lever 10, which swings back and forth, is interlocked with the threshing clutch lever 10 via a link mechanism 11, and is configured to be automatically and reversibly switched to the grain culm guiding posture in conjunction with the forward-entering operation of the lever 10. There is. Note that instead of using the threshing clutch lever 10 to switch the guide rod 9 as in this embodiment, the transmission clutch lever of the reaping processing section may be used to switch the guide rod 9, although this is not illustrated. Well, again,
Only when the threshing clutch lever 10 and the reaping clutch lever are both engaged and operated, the guide rod 9 is switched from the retracted position to the grain culm guiding position, and only when both levers are switched and operated, the guide rod 9 is retracted from the grain culm guiding position. Both levers and the guide rod 9 may be linked in order to switch to the posture.

Next, the steering device will be explained based on FIGS. 3 and 4.

Hydraulic pump 13 as a pair of fluid pressure pumps
The oil from a and 13b is transferred to the left and right crawler 1.
Hydraulic motors 12a and 12b as drive fluid pressure motors capable of forward and reverse rotation of the left and right crawlers 1a and 1b are separately supplied in a straight-ahead state, respectively.
The total amount of oil supplied to both hydraulic motors 12a, 12b in a spin turn in which the wheels rotate in opposite directions, and to one hydraulic motor 12a or 12b in a pivot turn in which only one of the left and right crawlers 1a, 1b is rotated. The pair of motors 12 are arranged so that the amount of oil supplied is approximately equal.
A steering valve mechanism is provided for supplying signals to the valves a and 12b. In other words, this valve mechanism functions as a directional switching valve that has the function of stopping the supply of oil from the pair of pumps 13a, 13b to the pair of motors 12a, 12b, and the function of switching the supply direction between forward and reverse. The three-position switching valves 14a, 14b and the oil from one pump 13b of the pair of pumps 13a, 13b are returned to the tank, and the oil from the other pump 1 is returned to the tank.
3a is branched in parallel to both the switching valves 14a, 14b, and the oil from each of the pair of pumps 13a, 13b is supplied to the switching valves 14.
an electromagnetically operated two-position switching valve 14c having a second action supplied separately to the valves a and 14b, and each of the two three-position switching valves 14a and 14b has a pair of left and right controls that can be swung back and forth. direction levers 15a, 15
and limit switches 16a and 1 that are pressed when the steering levers 15a and 15b are operated forward and backward, respectively.
6b, 17a, 17b, and these switches 16a are connected to the two-position switching valve 14c.
In contrast, a switch that is pressed when one lever is operated forward and a switch that is pressed when the other lever is operated rearward are connected in series. The steering levers 15a, 15
In the forward or reverse straight-ahead state where both of the wheels b are operated from the stopped state where both are operated to the neutral positions Na and Nb to the forward positions Fa and Fb or the rear positions Ra and Rb, the two-position switching valve 14c is set to the second position. 2 actions to supply oil from the pair of pumps 13a, 13b to the pair of motors 12a, 12b separately, so that one of the pair of steering levers 15a, 15b is placed in the forward position and the other is placed in the reverse position. In the operated spin turn state, the two-position switching valve 14c exhibits the first action, and the pair of pumps 13a, 1
The oil from the pump 13a of one of the pumps 3b is branched and supplied to the pair of motors 12a, 12b, and one of the pair of steering levers 15a, 15b is placed in a neutral position and the other is placed in a forward or reverse position. In the operated pivot turn state, the two-position switching valve 1
A pair of pumps 13 are made to exhibit a second action in 4c.
The pump is configured to supply oil from one of the pumps a and 13b to one of the pair of motors 12a and 12b. Therefore, this steering valve mechanism is effective when the horsepower of the mounted engine 5 is set to a small horsepower.

[Brief explanation of the drawing]

The drawings show an embodiment of the steering device for a working vehicle according to the present invention, and FIG. 1 is a side view of a combine harvester, FIG. 2 is a schematic perspective view showing the operation structure of the grain culm guide rod, and FIG.
The figure is a hydraulic circuit diagram, FIG. 4 is a perspective view of a steering lever mounting portion, and FIG. 5 is a hydraulic circuit diagram of another embodiment. 1a, 1b... traveling crawler, 12a, 12b
...Fluid pressure motor, 13a, 13b...Fluid pressure pump.

Claims (1)

[Claims] 1. A pair of fluid pressure pumps 13a, 13b and a pair of fluid pressure motors 12a, 12b capable of forward and reverse rotation, which drive the left and right crawlers 1a, 1b, respectively.
and the fluid pressure pump 13a,
The fluid from the 13b side flow path is transferred to each fluid pressure motor 12.
a state in which the fluid pressure motors 12a, 12b are driven to rotate in the same direction by supplying the fluid pressure motors 12a, 12b separately, and a state in which the fluid pressure motors 12a, 12b are supplied to drive the fluid pressure motors 12a, 12b to rotate in opposite directions. Then, the fluid from one pump 13a or 13b side passage is supplied to one fluid pressure motor 12a or 12b, and the fluid from the other pump 13b or 13a side passage is returned to the tank side passage, and both fluids are The fluid pressure motors 12a, 1 are in a state where only one of the pressure motors 12a, 12b is rotationally driven.
A directional switching valve 1 that can freely switch the direction of fluid supply from the fluid pressure pump 13a and 13b side channels to the fluid pressure pump 2b.
4a, 14b, and further includes a directional control valve 14a, 14 from the fluid pressure pump 13a, 13b
In the flow path leading to b, the fluid from one fluid pressure pump 13b is supplied only to the one direction switching valve 14b side, and the fluid from the one fluid pressure pump 13b is returned to the tank side flow path. The fluid from the other fluid pressure pump 13a is transferred to the two-way switching valves 14a, 14.
A steering device for a work vehicle, which is provided with a switching valve 14c that can be switched between supplying power in parallel to each of b.