JPH0728802Y2 - Oil amount adjusting device in work vehicle - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to an oil amount adjusting device in a work vehicle such as an agricultural tractor.

[Problems to be Solved by Prior Art and Invention] Generally, in this type of work vehicle, the actuator is actuated by supplying pressure oil from a hydraulic pump to elevate and lower the working unit, and Although other operations such as rolling posture control are performed, pressure oil is supplied to each of these actuators by dividing the pressure oil from the hydraulic pump with a flow dividing mechanism in the middle of the oil passage and supplying the pressure oil to each actuator. However, due to the difference in the operating capacities of the two actuators, an orifice is installed in the shunt flow path on the other actuator side so that a certain amount of pressure oil is supplied to that side, and the remaining surplus oil is used for lifting. There is one that is supplied to the branch flow passage on the actuator side. By the way, in this type, the amount of pressure oil supplied to the oil path on the actuator side for lifting is large enough to secure a sufficient amount of surplus oil when the engine is in a high idling state, such as during automatic work traveling. However, when the operation part is manually moved up and down in a low idling state due to a small work load such as when the aircraft is traveling, it is not possible to secure a sufficient amount of excess oil. As a result, there is a drawback that the raising and lowering speed of the working unit becomes slower, which hinders quick raising and lowering, and there is a problem that workability is lowered.

[Means for Solving Problems] The present invention has been made in view of the above circumstances and was devised with the object of providing an oil amount adjusting device for a work vehicle capable of eliminating these drawbacks. The pressure oil from the pump is divided into the actuator for raising and lowering the working section and the actuators for operation other than that, and the pressure oil is supplied to the flow dividing oil passage on the operation actuator side of the flow dividing mechanism to ensure a constant pressure oil supply. It is divided into a main oil passage and a bypass oil passage each provided with an orifice for
In a work vehicle configured to feed the remaining pressure oil supplied to the actuating actuator side to the lifting actuator side oil passage to raise and lower the working unit, in the bypass oil passage,
An oil amount adjusting valve mechanism that can be opened and closed to adjust the amount of pressure oil supplied to the lifting actuator side is provided, and the oil amount adjusting valve mechanism is one in which the working unit ascends and descends and manually operates the lifting operation tool. It is characterized in that it is linked to a manual detection mechanism that detects this and outputs a control command for closing the oil passage.

According to the present invention, the excess oil supplied to the lifting actuator-side oil passage during the manual operation is increased to prevent the working unit lifting speed from being slowed down. It is a thing.

[Embodiment] Next, an embodiment of the present invention will be described with reference to the drawings. In the drawings, reference numeral 1 denotes a traveling machine body of an agricultural tractor, and a rotary tillage type working section 3 is provided at a rear portion of the traveling machine body 1 so as to be vertically movable up and down via an elevating link mechanism 2.

Reference numeral 4 denotes a hydraulic pump, and pressure oil from the hydraulic pump 4 is diverted by a flow dividing mechanism 5 to an oil passage to the lift arm cylinder 7 side for vertically swinging the lift arm 6 and a lifting link mechanism 2. It is diverted so as to be supplied to an oil passage to a lift rod cylinder 2a for expanding and contracting either one of the left and right lift rods constituting the. Here, 8 is a switching valve mechanism for controlling expansion / contraction of the lift arm cylinder 7, and 9 is a switching valve mechanism for controlling expansion / contraction of the lift rod cylinder 2a.

In the housing of the flow dividing mechanism 5, a pump port P to which the pressure oil from the hydraulic pump 4 is supplied, an arm port B to supply the pressure oil to the lift arm cylinder 7 side, and a pressure oil to the lift rod cylinder 2a side are supplied. A rod port C, a return oil port D to which the return oil from the lift rod cylinder 2a is supplied, and a tank port T for returning the return oil to the oil tank 13 are provided. Then, the pressure oil supplied from the pump port P is divided by the flow dividing valve 10 to the arm port B and rod port C sides and supplied.
The main oil passage X from the pump port P to the rod port C is provided with a bypass oil passage Y in parallel, and these oil passages X and Y are provided with orifices (throttles) 11 and 12, respectively. Then, to the rod port C side, of the pressure oil supplied from the pump port P, a fixed amount of pressure oil narrowed down by the orifices 11 and 12 is supplied, while to the arm port B, the remaining surplus oil is supplied. It is being supplied.

Further, the bypass oil passage Y is provided with an oil amount switching valve 14 for switching the opening and closing (ON-OFF) of the oil passage. The oil quantity switching valve 14 is provided with a first solenoid 15, and when the first solenoid 15 is in an OFF operation state as described later, it is in an open state and, as described above, to the rod port C side. Pressure oil is supplied, but when it is in the ON operating state, it is closed and the pressure oil supply is stopped. As a result, the amount of pressure oil supplied to the rod port C side is the orifice 11 of the main oil passage X.
The oil amount is limited to a small amount that passes through only, and a large amount is supplied to the arm port B side by that amount.

FIG. 3 shows a main part of an electric circuit diagram including the first solenoid 15. Where R1, R2, R3, R4, R5 are the first,
The second, third, fourth, and fifth relay switches and their contact points, of which the first relay switch R1 is
The lever position detection sensor 17 that detects the lever position of the raising / lowering operation lever 16 for performing the raising / lowering operation of the working portion inputs the detection signal on the raising operation side to turn it on.The second relay switch R2 is , Above lever position detection sensor
It is designed to turn on by inputting the detection signal from the descending operation side from 17, and the third relay switch R3 is turned on by turning on the plowing depth automatic switching switch 18. ing. Then, when the raising / lowering operation lever 16 is operated to the upward side, the second relay switch R2 is turned on, whereby the second solenoid 19 provided in the switching valve mechanism 8 is actuated to switch the valve and divide the flow. The pressure oil thus supplied is supplied to the lift arm cylinder 7 side to extend it,
The working unit 3 is raised. On the other hand, when the raising / lowering operation lever 16 is operated to the descending side, the third relay switch R3 is turned on, whereby the third solenoid 20 provided in the switching valve mechanism 8 is actuated, and the lift arm cylinder 7 Valves are switched so that the oil in the oil tank 13 returns to the oil tank 13, so that the working unit 3 can be manually moved up and down by the lifting operation lever 16.

When the automatic plowing depth changeover switch 18 is turned ON, the third relay switch R3 is turned ON and the signal is input to the control unit 21 having a built-in microcomputer. ON-OFF switching control is performed by inputting the detected value from the depth detection sensor 22 and the set value from the plowing depth setter 23, and outputting the necessary control command to the control switches T1 and T2 based on these input values. The work unit 3 is automatically controlled to move up and down.

Further, in this one, there is provided an oil amount switching switch 24 which is turned on when the raising / lowering operation lever 16 is operated beyond the work area of the working portion to a position above a preset upper limit position. Switch 24 is the first solenoid
Wired in 15 power circuits. When the oil amount switching switch 24 is turned on by operating the lifting operation lever 16 to the upper limit position and the first solenoid 15 operates, the bypass oil passage Y is closed and the pressure oil is supplied to the rod port C side as described above. It is limited, and a large amount of pressure oil is supplied to the arm port B side by that amount, whereby the rising speed of the working unit 3 is set to be high.

On the other hand, the fourth relay switch R4 is configured to perform switching operation based on the detection signal from the oil temperature detection sensor 25. In other words, when the oil temperature is lower than the preset temperature, turn on the fourth relay switch R4 and turn on its switch contact R4.
The switch contact R4 is connected in parallel in the power circuit of the first solenoid 15 so as not to be related to the oil quantity switching switch 24. When the oil temperature is low, such as
As described above, as in the case where the oil amount switching switch 24 is turned on, the pressure oil supply to the rod port C side is suppressed, and a large amount of pressure oil is supplied to the arm port B side by that amount. It is considered that the working unit 3 can be quickly raised when the oil temperature is low.

In the flow dividing mechanism 10, the unload valve 26 is provided between the oil passage on the arm port B side and the oil passage on the tank port T. The solenoid 26a for switching the unload valve 26 between open and closed states. , The switch contact R5 is closed to stop the pressure oil from flowing to the tank port T side. The fifth relay switch R5 has the second and third solenoids 19 and 20. The switch contact R5 is provided in the power supply circuit of the switch circuit when current is supplied to either one of the solenoids 19 and 20 and the solenoid is operating.
Is closing. Then, in a neutral state in which the working unit 3 is not lifted or lowered, the pressure oil flowing in the arm port B is directly flown to the tank port T without flowing to the switching valve mechanism 5, and the pressure oil recirculation path at the time of unloading is performed. The length has been shortened as much as possible to reduce horsepower loss.

Further, in this structure, the hydraulic pump 4 is separated from the flow dividing mechanism.
In the flow path until reaching 10, a port for taking out pressure oil as an adapter for operating an auxiliary work machine such as a front loader is provided. So this is the first, second,
A valve housing provided with the third plugs 28, 29, 30, a pump port 31, an output port 32 connected to the side of the flow dividing mechanism 10 and the like is provided, but the oil passage from the pump port 31 is provided with a relief valve. Relief port connected to 27
33 is formed and further divided into two. A check valve mechanism 34 is formed in one of the oil passages.The check valve mechanism 34, when the first plug 28 is fixed,
The rod 28b provided on the first plug 28 presses the check ball 34a against the ammunition 34b, whereby the oil passage on the side is opened and the pressure oil from the pump port 31 is output to the output port. 32
It is supposed to output from.

On the other hand, the other oil passage communicates with the oil passage via an orifice 35 to form a bleed-off circuit. Then remove the first and second plugs 28 and 29 and connect the pipe 36 to the output port to the actuator for the attached work machine, while connecting the pipe 37 to the return oil port from the actuator on the attached work machine side. A pressure oil circuit is additionally formed to the machine actuator. In this case, the amount of pressure oil supplied from the output port 29a is adjusted by adjusting the residual oil of the oil flowing out through the orifice 35, thereby controlling the operating speed of the attached work machine to the optimum speed. I am able to do it. Incidentally, by appropriately adjusting the throttle amount of the orifice 35, it is possible to secure the pressure oil supply amount suitable for the type of the attached work machine.

In the embodiment of the present invention configured as described above, when the plowing work is performed in the plowing depth automatic state by turning on the plowing depth automatic switching switch 18, the lifting operation lever 16 is set to the plowing depth automatic position, In this automatic state, the oil quantity switching switch 24
Is in the OFF state, and the oil quantity switching valve 14 is open. Therefore, the pressure oil supplied to the pump port P passes through both the main oil passage X and the bypass oil passage Y and is supplied to the rod port C side, and the remaining excess oil is supplied to the arm port B. The vertical movement control and the horizontal movement control of the working unit 3 are automatically performed.

On the other hand, when traveling around the aircraft to move to the next work stroke,
The lifting operation lever 16 is set to the upper limit position to raise the working unit 3 higher than the working range. At this time, the hydraulic switching switch 24 is turned ON, and the operation of the first solenoid 15 is accompanied by this. At this time, the oil amount switching valve 14 is closed and the pressure oil supply of the bypass oil passage Y is closed, and the rod port C
The amount of pressure oil supplied to the main oil passage X is limited to only from the main oil passage X, while the pressure oil is additionally supplied to the arm port B side, so that the working unit 3 moves up at high speed. . In this way, when the automatic raising / lowering state is released by operating the lever and the working unit 3 is manually raised higher than the working range,
The ratio of pressure oil supply to the lift arm cylinder 7 side becomes higher than that during work traveling. Therefore, the work load is eliminated by raising the working unit 3 to a high level, and the engine speed is set to a low idling state. Therefore, even if the total pressure oil supply amount from the hydraulic pump 4 is reduced, The rising speed of the section 3 is set to a speed that is almost comparable to the speed in the high idling state in which the work traveling is performed, since the amount of oil corresponding to the closing of the bypass oil passage Y is additionally supplied. As a result, work efficiency can be improved.

Moreover, the switching of the oil amount adjustment can be automatically switched by manually operating the operating lever 16 for raising and lowering the working unit without the operator switching the members such as the switch. Therefore, it does not impose any work burden on the worker, and the simple operability is not impaired.

Of course, the present invention is not limited to the above-mentioned embodiment, and as a manual detection mechanism for controlling the opening / closing command of the bypass oil passage, the lifting operation lever is operated near the upper limit position as in the above-mentioned embodiment. It is not limited to the one that outputs the switching command to the closing side by detecting that the switching command is output to the closing side, and the switching command to the closing side may be immediately output by manually operating the lifting operation lever to the rising side. It suffices that the oil quantity switching switch provided in the above-mentioned embodiment is not provided in this, and as a result, the first relay switch which detects this when the elevating operation lever is manually operated to the ascending side is provided. The switch contact R1 is closed and the first solenoid 15 operates toward the oil passage closing side, and the surplus adjustment is automatically performed.

[Effects] In short, since the present invention is configured as described above, it is detected when the working unit is raised and lowered by a manual operation instead of an automatic work control state such as automatic plowing depth. In response to the detection signal from the manual detection mechanism, the oil amount adjusting valve mechanism operates to close the bypass oil passage, and limits the amount of pressure oil supplied to the other actuating actuator side. A large amount of pressure oil will be supplied to the oil passage on the side. As a result, even when the work load is reduced, such as when the machine is traveling, the engine speed decreases, and even if the overall pressure oil supply amount from the hydraulic pump decreases, the lifting speed of the working unit decreases. It is possible to effectively improve defects and improve work efficiency. Moreover, since the switching of the oil amount adjusting valve mechanism is automatically performed by the detection operation of the manual detection mechanism, the operator is not burdened with the work and the convenience of the operation is not impaired.

[Brief description of drawings]

FIG. 1 shows an embodiment of an oil amount adjusting device for a work vehicle according to the present invention. FIG. 1 is an overall side view of an agricultural tractor, FIG. 2 is a hydraulic circuit diagram of essential parts, and FIG. 4 is an exploded sectional view of the adapter oil passage, and FIG. 6 is a side view of the same. In the figure, 1 is a traveling body, 2a is a lift rod cylinder, 3 is a working unit, 5 is a flow dividing mechanism, 7 is a lift arm cylinder, and 14 is a lift arm cylinder.
Is an oil amount switching valve and an oil amount switching switch 24.

Claims (1)

[Scope of utility model registration request] 1. A diversion oil passage on the side of an actuating actuator of a diversion mechanism, which divides and supplies pressure oil from a hydraulic pump to an actuator for raising and lowering a working part and an actuator for actuation other than that, respectively. It is configured by dividing it into a main oil passage and a bypass oil passage each provided with an orifice to secure the pressure oil supply, and supplies the remaining pressure oil supplied to the actuating actuator side to the lifting actuator side oil passage. In the work vehicle configured to raise and lower the working unit, the bypass oil passage is provided with an oil amount adjusting valve mechanism that can be opened and closed to adjust the pressure oil supply amount to the lifting actuator side. The oil amount adjusting valve mechanism is connected to a manual detection mechanism that outputs a control command for closing an oil passage by detecting that the working unit is being lifted and lowered by manually operating a lifting operation tool. Work to Oil amount adjusting device in.