JPH0826126A - Turning device in mobile agricultural machine - Google Patents

Abstract

PURPOSE:To allow a rapid turning with small steering amount of a steering wheel by rapidly feeding the pressurized fluid to a power steering cylinder when a machine body is turned. CONSTITUTION:The pressurized fluid can be fed from a pressurized fluid feeding means 15 to a quick turn device 16 by operating an elevating device 13 of a working machine to steer a steering wheel 7a, and a machine body is turned by differentiating the rotational speed of front wheels and rear wheels. The pressurized fluid to be fed from a pressurized fluid feeding means 15 by control means 26, 27r, 27l is switched from the flow through a power steering unit 23 to the flow to directly feed the pressurized fluid to power steering cylinders 25r, 25l.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a turning device for a mobile agricultural machine, and more particularly to a turning device for a moving agricultural machine which enables a sharp turning with a small amount of operation of a steering wheel when turning a rotary by turning. Is.

[0002]

2. Description of the Related Art As an example of a conventional turning device for a mobile agricultural machine, when a rotary is raised to turn a headland and a steering angle of a steering wheel exceeds a predetermined value, a brake for a rear wheel inside a turning radius is provided. There is one that can be operated by hydraulic pressure to make a quick turn with a minimum radius.

As another example of a turning device in a mobile agricultural machine, when turning a rotary to turn, a front wheel is made to have a double speed as compared with a rear wheel where a turning radius is large because of four-wheel drive. There is also one that enables a small turn, and enables a quick turn without damaging the headland in a short time without rubbing the soil.

[0004]

The latter of these, the turning device in the mobile agricultural machine, is capable of performing a quick turn when the turning angle of the front wheels is about 40 °, but even in this case, the steering wheel operation amount is It is necessary to rotate about 1.5 times, quick steering wheel operation is required when turning the aircraft, and it is necessary to rotate the steering wheel by the same amount when returning the steering wheel, and many headlands remain, There is a problem such as not being able to reliably carry out adjoining.

The present invention has been made in order to solve the above problems. When the machine body is rotated, pressure oil is quickly supplied to the power steering cylinder, and a sharp turn is made with a small operation amount of the steering wheel. It is an object of the present invention to provide a swivel device in a mobile agricultural machine that can be used.

[0006]

In order to achieve the above object, therefore, in the turning device of the mobile agricultural machine according to the present invention, the pressure oil supply means (1) driven by the engine (6) is used.
5), a working machine lifting device (13) operated by the pressure oil from the pressure oil supply means, and a steering wheel (7).
Operated by steering a), front wheels (2) and rear wheels (3)
Of the steering wheel (7) and a quick turn device (16) for turning the airframe (5) with different rotational speeds of the
a) a power steering unit (23) for controlling the flow of pressure oil from the pressure oil supply means (15) to the power steering cylinders (25r, 25l) by steering in a). During operation of the device (13), the power steering cylinder (25) corresponding to the steering state of the steering wheel (7a).
Control means (26, 2) for controlling the switching of the pressure oil supply to r, 25l) between the flow supplied via the power steering unit (23) and the flow supplied directly.
7r, 27l).

More preferably, a steering angle detecting means (43) for detecting that the steering wheel (7a) is steered by a predetermined angle or more is provided, and the operation of the quick turn device (16) and the power steering cylinder (25r) are provided. , 25l) is switched by steering the steering wheel (7a), and switching control for directly supplying pressure oil to the steering cylinders (25r, 25l) is performed by the quick turn device (1).
6) is switched to the operating state at an angle smaller than the steering angle of the steering wheel (7a).

[0008]

[Operation] Based on the above configuration, the working machine lifting device (13)
By operating the steering wheel (7a) to supply the pressure oil from the pressure oil supply means (15) to the quick turn device (16), and the front wheels (2) and the rear wheels (3) can be supplied. The machine body (5) is turned with different rotational speeds. In this case, the control means (26, 27
The pressure oil supplied from the pressure oil supply means (15) by the r, 27l) is the power steering unit (2).
The flow via 3) will be switched to the flow directly supplied to the power steering cylinders (25r, 25l).

Further, the quick turn device (16)
And the power steering cylinder (25
r, 25l) is switched by the steering of the steering wheel (7a), and the power steering cylinder (25) is operated by the steering angle detecting means (43).
The switching control for directly supplying the pressure oil to r, 25l) is performed at an angle smaller than the steering angle of the steering wheel (7a) that switches the quick turn device (16) to the operating state.

[0010]

Embodiments of the present invention will be described below in detail with reference to the drawings.

1 to 4 are views showing a first embodiment of the present invention. FIG. 1 is a hydraulic circuit diagram of a turning device in a mobile agricultural machine of the present invention, FIG. 2 is a control circuit diagram of the same, and FIG. 4 is a side view showing the mobile agricultural machine. In the figure, a tractor 1 as a mobile agricultural machine has, as shown in FIG. 4, a body 5 supported by a front wheel 2 and a rear wheel 3 each having a front wheel breaking angle sensor 2a for detecting the amount of forward and backward movement of a tie rod. The machine body 5 is provided with an engine 6 on the front side, a steering wheel 7a on the driver's seat 7 in the center, and a mission case 9 on the rear side.

The transmission case 9 has a main transmission (not shown) in which a main transmission lever 10 is connected in series, and a sub-transmission lever 11 in addition to the main transmission. And a transmission system for transmitting the driving force only to the two wheels, that is, the rear wheels 3 and a four-wheel drive, that is, transmitting the driving force to the front wheels 2 together with the rear wheels 3. The drive force switching device (not shown) having a drive force switching lever (not shown) for switching between the transmission system and the four-wheel drive system, and the front wheel 2 is rotated at a speed approximately twice that of the rear wheel 3. It has a built-in quick turn switching device (not shown) having a quick turn switching lever (not shown) that switches between a quick turn system for transmission and a driving force switching device and a quick turn switching device for two-wheel drive positive ® down, the control valve 12 having a control lever 12a for switching to the four-wheel drive position and the quick turn position (see FIG. 1) is incorporated. And this control valve 12
Is provided with a lift arm 13 as a working machine lifting device that lifts and lowers a working machine (not shown) such as a rotary by supplying pressure oil.

FIG. 1 shows a hydraulic circuit for operating the control valve 12. This hydraulic circuit is a pump 15 which is a pressure oil supply means driven by an engine 6, and a quick turn device when the pump 15 operates. The quick turn diversion circuit 17 that diverts a constant flow amount of pressure oil to the shift rail 16 and a controlled constant flow amount of pressure oil is preferentially supplied from the quick turn diversion circuit 17 via the relief valve 19. The hydraulic lift shunt circuit 20 for flowing the remaining pressure oil to the other control valve 12 and the solenoid valve 2a.
0a, a lift rod cylinder 21 that keeps a rotary (not shown) in a horizontal state, and a main switch (see FIG. 2) described later for making a quick turn of the machine body 5 are turned off, pressure oil from the pump 15 is turned off. Is the solenoid valve 2 when steering the normal steering wheel 7a.
Power steering unit 23 supplied via 2
And power steering cylinders 25r, 25 for reducing the steering force of the steering wheel 7a by supplying pressure oil from the power steering unit 23.
l and the steering wheel 7 during a quick turn
and a pressure switch 26 serving as a switch means for switching the solenoid valve 22 so as to directly supply pressure oil to the power steering cylinders 25r and 25l. Pressure switches 27r and 27l are connected between the power steering cylinders 25r and 25l. A check valve 29 is connected between the solenoid valve 22 and the power steering unit 23. Then, in the power steering unit 23, a solenoid valve 23a and a gear pump 23 for operating one of the power steering cylinders 25r and 25l according to the steering direction of the steering wheel 7a.
b is built in. Note that reference numerals 30a and 30b in the drawing denote throttle valves for controlling the amount of oil supplied to the power steering cylinders 25r and 25l.
Are arranged to stabilize the operation of the pressure switches 27r and 27l. Reference numeral 31 is a hydraulic cylinder that is connected to the control valve 12 and operates a lift arm 13 that raises and lowers a rotary (not shown).

Next, a control circuit for controlling the flow of pressure oil from the pump 15 of the hydraulic circuit shown in FIG. 1 will be described with reference to FIG.
A main switch 33 is connected in series to the power supply 32 of the control circuit, and a pilot lamp 35 that detects whether the main switch 33 is in an on state or an off state is connected. The main switch 33 includes a PTO switch 36a which is turned on / off in conjunction with a PTO gear shift lever 36,
A lift arm switch 37 interlocked with the operation of the lift arm 13 and a high speed cut-off switch 39 that is opened when the machine body 5 travels at high speed are connected in series. A series circuit of the pressure switch 26 and a timer 40 is connected in parallel to the pilot lamp 35. Further, a series circuit of the pressure switch 29r and the timer 41, which is turned on by the right steering of the steering wheel 7a, is connected to a series circuit of the pressure switch 29l, which is turned on by the left steering of the steering wheel 7a. They are connected in parallel, and the timer 40 is connected to this parallel circuit.
The circuit in which the normally open contacts 40a interlocked with the operation of is connected in series to the pilot lamp 35. Further, the pilot lamp 35 includes a normally open contact 41 a that interlocks with the operation of the timer 41, a normally closed contact 42 b that interlocks with the operation of the timer 42, and the solenoid valve 22.
A series circuit with one coil 22r is connected in parallel. The pilot lamp 35 includes the timer 42.
Normally open contact 42a interlocking with the operation of the timer 41, normally closed contact 41b interlocking with the operation of the timer 41, and the solenoid valve 2
A series circuit with the second coil 22l of No. 2 is connected in parallel.

Next, the operation will be described.

When the drive force switching device is in the two-wheel drive position, when the auxiliary transmission lever 11 is switched to the high speed side even when the drive force switching device is in the four-wheel drive position, and the auxiliary transmission lever Even if 11 is on the low speed side, if the quick turn switch (main switch 33) of the quick turn switching device is off,
The pressure oil supplied from the pump 15 by steering the steering wheel 7a is supplied to the power steering unit 23 via the check valve 29, and then from this power steering unit 23, either the left or right power steering cylinder 25l, 25r. Is supplied to.

The main switch 33 of the quick turn switching device is turned on when the drive force switching device is in the four-wheel drive position and the auxiliary transmission lever 11 is switched to the low speed side. Then, by operating the PTO gear shift lever 36, the PTO switch 36a
Is closed, and the lift arm 13 is raised to the highest position, the lift arm switch 37 is closed. When the steering wheel 7a is steered to the left or right in this state, the pressure switch 26 is closed (see FIG. 3a), the timer 40 operates, and the normally open contact 4
0a will be closed for the time shown in FIG. 3b. Now, for example, if the steering wheel 7a is steered to the right, the pressure switch 27r is closed for the time shown in FIG. 3c, and the normally open contact 41a is turned on for the same time as shown in FIG. 3 and the normally closed contact 41b is in the state shown in FIG.
3 is in the off state for a time longer than the time indicated by d in FIG. As a result, the solenoid valve 22 is switched and operated, so that the pressure oil from the pump 15 is directly supplied to the power steering cylinders 25r and 25l, which operates at high speed. That is, the power steering cylinder 25
Since pressure oil is rapidly supplied to r and 25l by a small operation amount of the steering wheel 7a, the shift rail 16 is pushed by the pressure oil from the quick turn diversion circuit 17, and the sleeve is driven by the quick turn. By moving to the gear side and the front wheel becomes twice as fast as the rear wheel, the quick turn of the machine body 5 becomes possible.

After the vehicle makes a sharp turn in this way, the pressure switch 27l is closed by steering the steering wheel 7a (FIG. 3c), and the normally open contact 42a is in the on state (FIG. 3). In addition, the normally closed contact 42b is turned off. At this time, the normally open contact 41a of the timer 41 is already in the off state, but the normally closed contact 41b of the timer 41 is still in the off state.
Even when the normally open contact 42a of the above is turned on, no current flows through the coil 22l of the solenoid valve 22, and therefore the solenoid valve 22 does not switch. Therefore, the pressure oil from the pump 15 is supplied to the power steering cylinders 25r and 25l through the normal path passing through the power steering unit 23, and the body 5 is turned at a normal speed. , It becomes easier to carry out adjacent shunting.

The flow rate of the pressure oil supplied from the pump 15 can be set by adjusting the pump 15 or the throttle valve 30a.

Further, since the sharp turn is possible only when the lift arm 13 is raised to the uppermost position, it is possible to bend while plowing the machine body 5.

Next, a second embodiment according to the present invention will be described with reference to FIG.

In the first embodiment, the main switch 3 is turned on, the PTO switch 36a and the lift arm switch 37 are closed, and the steering wheel 7a is steered to close the pressure switch 26. Although the solenoid valve 22 is switched and the pressure oil is directly supplied from the pump 15 to the power steering cylinders 25r and 25l, such a configuration may make it difficult to steer the machine body 5 straight ahead. .

Therefore, in the second embodiment, when the steering wheel 7a is steered by a predetermined angle or more, this is detected to enable a quick turn of the machine body 5 with a slight operation amount of the steering wheel 7a. Make it easy to steer the machine body 5 straight ahead.

That is, in the control circuit of the second embodiment shown in FIG. 5, the front wheel turning angle sensor 43, which is steering angle detecting means, is connected in parallel to the series circuit of the pressure switch 26 and the timer 40. When 43 detects steering of the steering wheel 7a at a predetermined angle or more, the normally open contact 43a that is linked to the front wheel breaking angle sensor 43 is closed to supply current to the pressure switch 26. is there. In FIG. 5, the same or equivalent components as those in FIG. 2 are designated by the same reference numerals, and duplicate description will be omitted.

With this configuration, when the steering angle of the steering wheel 7a is less than the predetermined angle, the pressure oil from the pump 15 is transmitted through the power steering unit 23 to the power steering cylinder 25.
r, 25l, and when the angle is greater than a predetermined angle, the solenoid valve 22 is switched and the pressure oil from the pump 15 is directly supplied to the power steering cylinders 25r, 25l via the solenoid valve 22. Become. The switching control for directly supplying the pressure oil to the power steering cylinders 25r and 25l by the front wheel turning angle sensor 43 is performed at an angle smaller than the steering angle of the steering wheel 7a for switching the quick turn device 16 to the operating state.

[0026]

As is apparent from the above description, according to the present invention, by operating the work implement lifting device and steering the steering wheel, the pressure oil can be supplied from the pressure oil supply means to the quick turn device. It becomes possible, and when rotating the aircraft with different front and rear wheel rotation speeds,
The pressure oil supplied from the pressure oil supply means is switched by the control means from the flow through the power steering unit up to that time to the flow directly supplied to the power steering cylinder, so that a small steering wheel operation amount is required. Allows quick supply of pressure oil to the power steering cylinder, which enables quick turning with a small amount of steering wheel steering, which eliminates the hassle of turning and reduces headland. Therefore, the work efficiency is increased, and fatigue is reduced. Further, since a sharp turn can be made only when the working machine is raised at a low speed, accidents due to erroneous operation can be prevented.

Further, since the operation of the quick turn device and the switching control of the pressure oil supply to the power steering cylinder are performed at an angle smaller than the steering angle of the steering wheel for switching the quick turn device to the operating state, In addition to being able to make a quick turn, it is also easy to return the steering wheel to a straight-ahead state, and it is easier to get adjacent.

[Brief description of drawings]

FIG. 1 is a circuit diagram of a first embodiment of a hydraulic circuit of a turning device in a mobile agricultural machine according to the present invention.

FIG. 2 is a circuit diagram showing a control circuit of the above.

FIG. 3 is a timing chart of a control circuit.

FIG. 4 is an overall view of a mobile agricultural machine.

FIG. 5 is a circuit diagram of a second embodiment of the control circuit of the turning device in the mobile agricultural machine according to the present invention.

[Explanation of symbols]

 2 front wheel 3 rear wheel 5 machine body 6 engine 7a steering wheel 13 lift arm (working machine lifting device) 15 pressure oil supply means (pump) 16 quick turn device 23r power steering unit 23l power steering unit 25r power steering cylinder 25l power steering cylinder 26 Pressure switch (control means) 27r Pressure switch (control means) 27l Pressure switch (control means)

Claims (2)

[Claims] 1. A pressure oil supply unit driven by an engine, a working machine lifting device that moves up and down by the supply of pressure oil from the pressure oil supply unit, and a front wheel and a rear wheel that operate by steering a steering wheel. A turning device in a mobile agricultural machine including a quick turn device for turning the machine body with different rotational speeds, and a power steering unit for controlling the flow of the pressure oil from the pressure oil supply means to the power steering cylinder by steering the steering wheel. In the operation of the work implement lifting device, pressure oil is directly supplied to the power steering cylinder in response to a steering state of the steering wheel, with a flow supplied via the power steering unit. A mobile agricultural machine, characterized by comprising a control means for switching control to a desired flow. Definitive turning device. 2. Steering angle detection means for detecting that the steering wheel has been steered by a predetermined angle or more, and the steering wheel is operated to switch the operation of the quick turn device and to switch the pressure oil supply to the power steering cylinder. 3. The switching control for directly supplying pressure oil to the steering cylinder is performed at an angle smaller than the steering angle of the steering wheel that switches the quick turn device to an operating state. Turning device for mobile agricultural machinery.