JPH071980A - Front wheel rotation driving control device for four-wheel drive type moving vehicle - Google Patents

Abstract

PURPOSE:To carry out control in response to a ground surface condition by switching the control to turning control when a steering angle reaches a prescribed value or more, switching it to rectilinear movement control when the steering angle does not reach the prescribed value, and switching it to full turn control or small steering angle turning control according to a change in rotating speed of rear wheels after being switched to the turning control. CONSTITUTION:Signals of rear and front shaft rotation sensors 9 and 10 and a steering angle sensor 11 are inputted to a CPU13, and when the steering angle sensor 11 detects a prescribed value or more, 'turning control F' is carried out, and when a steering angle does not reach the prescribed value or more, 'rectilinear movement control G' is carried out. After being switched to the 'turning control F', control is switched to full turn control or small steering angle turning control according to a change in a detecting value of the rear shaft rotation sensor 9. Thereby, since the control is carried out in response even to a change after that by selecting prescribed control from plural control operations by a control means, the control operation can be carried out speedily while having a large number of controls.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a front wheel rotation drive control device for a four-wheel drive type mobile vehicle.

[0002]

2. Description of the Related Art As conventional techniques, a four-wheel drive vehicle is a two-wheel drive during turning in which the front wheels are turned off and the two rear wheels are turned during turning, and the average peripheral speed of the front wheels is determined by the rear wheels during this turning. On the other hand, there is a front wheel speed-increasing four-wheel drive during turning, in which the speed is increased by about two times when turning.

[0003]

However, such a conventional device merely mechanically controls in accordance with the standard operating sequence initially set, and the ground condition is changed to make control operation impossible. Even if it occurs, it is ignored and the control operation is performed with the first setting. Such a conventional one has no problem when traveling on the ground in a standard condition where constant conditions continue,
If straight running or turning running is performed in a muddy area or a place where uneven road surfaces are mixed, running performance may deteriorate or the vehicle may not run.

That is, if the rear two-wheel drive is simply switched during turning, if one of the rear wheels slips in the muddy ground,
If the vehicle body cannot move forward due to the action of the differential device in the middle part of the rear wheel, or if the rear wheel slips when the vehicle is turning downhill on a bumpy road surface, only the rear wheel supports the weight of the vehicle and the engine brake May not run and the car body may run away to the lowland side.

[0005]

SUMMARY OF THE INVENTION The present invention is intended to solve such a problem of the conventional apparatus, and has taken the following technical means. That is, as the first configuration, the direct coupling clutch 7 capable of switching between "rear wheel two-wheel drive state C", "front and rear four-wheel drive state H", and "front wheel speed-increasing four-wheel drive state D".
And a speed-up clutch 8. A rear vehicle rotation sensor 9, a front axle rotation sensor 10, and a steering angle sensor 11 are provided, and detection values of these sensors 9, 10, 11 are provided to a control unit 13. The steering angle sensor 1
When "1" detects a steering angle equal to or more than a predetermined value, "turning control F" is controlled, and when the steering angle sensor 11 does not reach a steering angle equal to or more than a predetermined value, "straight control G" is controlled. After being switched to "turning control F" by "control means I", further switching to "full turn control" or "small rudder angle turning control" is performed according to a change in the detected value of the rear axle rotation sensor 9. The configuration of the front wheel rotation drive control device for a wheel drive type mobile vehicle is switched to "rear wheel two-wheel drive state C", "front and rear four-wheel drive state H" and "front wheel speed-increasing four-wheel drive state D" as the second configuration. A mobile vehicle having a direct coupling clutch 7 and a speed increasing clutch 8, which are provided with a rear axle rotation sensor 9, a front axle rotation sensor 10 and a steering angle sensor 11, and the detection values of these sensors 9, 10, 11 are provided. For transmitting to the control unit 13 When the steering angle sensor 11 detects a steering angle equal to or larger than a predetermined value, the control is "turning control F", and when the steering angle sensor 11 does not reach the steering angle equal to or larger than the predetermined value, "straight control G" is controlled. Is provided, and after switching to "turning control F" by "control means I", further switching to "full turn control" or "small rudder angle turning control" is performed according to the change in the detected value of the steering angle sensor 11. The front wheel rotation drive control device for the four-wheel drive type moving vehicle is configured as described above, and the third configuration has a direct coupling clutch 7 that can be switched between "rear wheel two-wheel drive state C" and "front and rear four-wheel drive state H". Rear vehicle rotation sensor 9
In addition, in the case where the front shaft rotation sensor 10 is provided and the detection values of the respective sensors 9, 10 are transmitted to the control unit 13, the front and rear shaft rotation sensors 10, 9 while traveling in the “rear wheel two-wheel drive state C” for a short period of time. "Detection mechanism E" to detect the rotating peripheral speed of
Is provided, and the front shaft rotation sensor 10 is detected by the "detection mechanism E".
When the detected value of the rear axle rotation sensor 9 becomes less than a predetermined value even though the detected value of No. does not change, the "control means I" for turning on the direct coupling clutch 7 to switch to the "front-rear four-wheel drive state H" is provided. And a front wheel rotation drive control device for a four-wheel drive type moving vehicle.

[0006]

Embodiments of the present invention will be described in detail below with reference to the drawings. The illustrated example is an agricultural tractor 14, and the front wheels 4, 4 drive section of the agricultural tractor 14 are
This invention is incorporated. Agricultural tractor 14
The front-rear four-wheel drive type mobile vehicle is equipped with front-rear wheels 4, 4, 3, 3 at four front-rear corners of the machine body.
It is driven using the power of.

The front and rear wheels 4, 4, 3 and 3 are connected to front and rear axle cases 15 and 16, respectively, and project outwardly, and their base ends are a front frame 17 and a gear case which is a main frame. It is attached to 18, etc. The rear end of the front frame 17 is a machine frame integrally assembled to the main frame side,
The engine 1 is detachably attached to the front portion of the front frame 17 which is the machine frame.

The central portion of the front axle case 15 in the left-right direction is pivotally attached 19 to the front frame 17 so that the front wheels 4 can move up and down due to the unevenness of the ground. A front differential device 20 is provided in the center of the front axle case 15 in the left-right direction, and the front differential device 20 is input through a front drive shaft 6 that projects from a transmission case 21 to be described later.

A radiator 22 and a cooling fan 23 are arranged in front of the engine 1. Reference numeral 12 denotes an engine rotation sensor, which is provided in the vicinity of the cooling fan 23 in the illustrated example to measure the rotation speed of the engine 1 and transmit it to the CPU 13 which is the control unit. For example, the rotation of a crankshaft (not shown) or other rotating parts may be detected.

A hood 24 covers the front and side of the engine 1 and auxiliary devices (not shown). Reference numeral 26 is a clutch housing, which has a main clutch 27 inside and is attached to the rear portion of the engine 1, and which transmits a driving force to a rear transmission case 21 portion, is a handlebar, and 29 is a handle post. Handle post 2
The lower end of 9 is attached to the machine frame, and although not shown, when the handle 28 is rotated left and right, the front wheels 4 and 4 are swung to the left and right.

The left and right steering angles of the front wheels 4, 4 are read by the steering angle sensor 11 and transmitted to the CPU 13. Fender 3 from the front to the upper of the left and right rear wheels 3,3
0 and 30 are attached, and the left and right fenders 30 and 3
A seat 31 is provided between 0s. The left and right rear wheels 3, 3 are connected left and right by a rear axle case 16, and a rear differential device 25 is provided in the middle portion between the left and right.

The gear case 18 containing the rear differential device 25 is attached to the rear portion of the transmission case 21 described above, and the transmission case 21 is integrally connected to the rear end portion of the clutch housing 26. From the driver's feet at the bottom of the seat 31 to both sides of the bottom of the handle post 29,
A substantially flat plate-shaped floor 32 is attached.

The floor 32 is substantially flat in the left-right direction and has an outer width that is close to the outer edge portions of the left and right fenders 30, 30, that is, a width close to the entire width of the body. The driving force from the engine 1 via the main clutch 27 is input from the front part of the transmission case 21. Although not shown in detail, the input driving force is transmitted to the rear differential device 25 through the transmission mechanism 2 which is a part or all of the reverser device 33, the main transmission device 34, the auxiliary transmission device 35, etc., which shifts forward and backward. It is divided into two systems: a traveling wheel drive system that reaches and a PTO drive system 36 that is an external power take-out that is branched at the entrance of the transmission case 21.

Reference numeral 37 denotes a PTO shaft, which is a gear case 1.
8, the input shaft to various working machines (not shown) can be detachably attached to this rear portion. The output shafts 75, 75 are projected left and right from the rear differential device 25, and the left and right rear wheels 3, 3 are attached to the rear of the transmission path provided with the left and right brakes 76, 76 in the middle of the output shaft 75.

The left and right rear wheels 3, 3 are independently or simultaneously braked by independent left and right brake petals (not shown). Any drive shaft may be used while it is output from the speed change mechanism 2 and input to the rear differential device 25, but the drive force of the rear wheel drive rotary shaft 5 part, which is this drive shaft, is passed through the output gear 38, the counter gear 39, and the main gear 40. Communicate to.

The main gear 40 is engaged with the spline portion of the first clutch boss 41 and rotates integrally with the boss. Further, another sub gear 42 is attached by engaging with this spline portion, and the main and sub gears 40, 42 rotate simultaneously. These are two gears in the illustrated example, but the main and sub gears 40, 42 may be one if the number of teeth is not a problem.

A counter inlet gear 43 is always meshed with the sub gear 42, and a counter outlet gear 45 connected by a connecting drive shaft 44 is also integrally rotatable. The counter exit gear 45 is the second clutch gear 4
6 always meshes with this second clutch gear 46
The second clutch boss 47, which is integral with, can be simultaneously rotated.

In other words, when the main gear 40 rotates, the first clutch boss 41 and the second clutch boss 47, which are provided on the front drive clutch shaft 48 so as to face each other and are freely rotatable, simultaneously rotate, and the main gear 40 moves. When stopped, the first and second clutch bosses 41 and 47 stop at the same time. The counter inlet gear 43 is accelerated by the sub gear 42, and the second clutch gear 46 is accelerated by the counter outlet gear 45. When the first clutch boss 41 makes one rotation, the second clutch boss 47 is substantially rotated. Rotate twice.

A first piston 49 and a second piston 50 are disposed between the first and second clutch bosses 41 and 47, and a drive drum 52 containing a plurality of friction plates 51 and 51 is mounted on the outer circumference thereof. Is covered. The drive drum 52 is divided into front and rear by a partition wall 53, and the first clutch boss 41 at the rear portion, the friction plate 51 and the first piston 49 constitute a direct coupling clutch 7, and the drive drum 52 frictions at the second clutch boss 47 at the front portion. Board 51
The second piston 50 constitutes the speed increasing clutch 8.

The drive drum 52 has a front drive clutch shaft 48.
It is integrated into the spline part of the. Lubricating oil 54 is held in the transmission case 21 to lubricate each transmission gear and shafts. A part of the lubricating oil 54 is sucked and pressurized by the oil pump 55, and the first piston 49 of the direct coupling clutch 7 and the partition wall 53 are connected via the oil passage switching valve 58.
It is supplied to either one of the first oil chamber 56 portion between them or the second oil chamber 57 portion between the second piston 50 of the speed increasing clutch 8 and the partition wall 53.

The oil passage switching valve 58 shown in FIG. 2 is in the neutral state. In this neutral state, both the direct coupling clutch 7 and the speed increasing clutch 8 are in the OFF state. Next, when the first solenoid 59 is energized, the oil passage switching valve 58 switches to the valve 58a portion, the high pressure oil flows into the first oil chamber 56, and the direct coupling clutch 7
The rotation of the rear wheel drive rotary shaft 5 is transmitted to the front drive clutch shaft 48.

When the second solenoid 60 is energized, the oil passage switching valve 58 is switched to the valve 58b portion so that the high pressure oil is transferred to the second oil chamber 5
7, the speed increasing clutch 8 is connected, and the rotation of the rear wheel drive rotary shaft 5 is almost doubled and transmitted to the front drive clutch shaft 48. The rotation of the rear wheel drive rotary shaft 5 input to the front drive clutch shaft 48 is interlocked with the front drive shaft 6 described above, and drives the front wheels 4, 4 via the front differential device 20.

As described above, when the direct coupling clutch 7 is ON and the speed increasing clutch 8 is OFF, the rotation of the front drive shaft 6 is in the "front and rear four-wheel drive state H" in which the direct drive clutch 6 is driven at substantially constant speed. Is OFF and the speed increasing clutch 8 is ON, the rotation of the front drive shaft 6 is a “front wheel speed increasing 4WD state D” in which the speed is doubled, and both clutches 7 and 8 are OFF. The front drive shaft 6 is simply in the rolling state and is not driven in the "rear wheel two-wheel drive state C". (While the front wheels 4 are in the rolling state,
When the aircraft moves, it is pulled and rotates, and when the aircraft stops, it stops. ) 61 is a drain oil passage for releasing the pressure oil in the oil passage associated with the switching of the oil passage switching valve 58 to the transmission case 21.

In the illustrated example, the transmission case 21 is used as an oil sump, but a separate oil tank may be provided exclusively. A rear shaft rotation sensor 9 is arranged near the counter outlet gear 45, and a front shaft rotation sensor 10 is arranged near the driving drum 52, and the control unit reads the rotation speeds of the respective rotating units. It is transmitted to a certain CPU 13.

First, the agricultural tractor 14 of the present invention will be described.
Driving in the "rear wheel two-wheel drive state C" in which only the rear wheels 3 are driven,
During this traveling, the steering angle of the steering wheel 28 is detected by the steering angle sensor 1.
When the steering angle exceeds the set angle, the control by the "turning control F" is performed. When the set angle is not exceeded, the "straight control G" is controlled by the "control means I" described later. It is based on the order.

This control will be described with reference to the flowchart shown in FIG. When the control device operates, first the first solenoid 59 and the second solenoid 60 are initially set.
Is turned off, the driving force to the front wheels 4 and 4 is cut off, and the vehicle starts traveling in the "rear wheel two-wheel drive state C", which is the traveling with only the rear wheels 3 and 3, and further reads various data. Going away.

First, "the rear wheel two-wheel drive state C" toward the front
When the agricultural tractor 14 that is traveling in the steering wheel steers the steering wheel 28 and the steering angle of the front wheels 4, 4 is determined by the steering angle sensor 11 to exceed the set angle “α” (probably 5 degrees), the subroutine If the steering angle of the front wheels 4 and 4 is determined to be less than or equal to the set angle "α" by the steering angle sensor 11, the operation of the "turning control F" is processed based on the command of the "control means I". The operation of the "straight ahead control G" which is a subroutine is processed based on the command of the "control means I".

In the control of the "turning control F" which is a subroutine, as shown in the flowchart of FIG. 6, when all the conditions are satisfied, the "full turn control" at a large steering angle is carried out. If denied, the control is changed to "small steering angle turning control" at a small steering angle. More specifically, referring to FIG. 6, when the "turning control F" is started, first, as initialization, data in a "straight ahead control G" described later is initialized, that is, the first solenoid 59 and the second solenoid 60 are turned off, and The vehicle starts running in the "rear wheel two-wheel drive state C" in which the driving force to the wheels 4 and 4 is cut off.

It is judged whether or not the speed-increasing turning switch 64, which is turned on or off manually, is turned on.
It is determined whether or not the vehicle speed averaged on the left and right of the rear wheels 3 and 3 read by the rear axle rotation sensor 9 has reached the set vehicle speed "V" (about 4 Km / H), and the set vehicle speed "V" has not been reached. The steering angle of the front wheels 4 and 4 read by the steering angle sensor 11 exceeds γ (approximately 40 degrees to one side from the straight traveling state), and a working machine (not shown) attached to the end of the agricultural tractor 14 so as to be vertically movable. When the position lever 66 for operating the ascending / descending position is operated to raise, the "full turn control" that may travel in the "front wheel speed-increasing 4WD state D" is activated.

Next, the steering angle of the front wheels 4 and 4 when the speed-increasing turning switch 64 is OFF, when the vehicle speeds of the rear wheels 3 and 3 averaged over the left and right exceed the set vehicle speed "V". Does not reach γ, and when the position lever 66 for operating the ascending / descending position of the working machine maintains the lowered position operation,
If all or any of the conditions are met,
Activate the "small rudder angle turning control".

Thus, here, the rear shaft rotation sensor 9
When the vehicle speed is low, the "front wheel speed-increasing 4WD state D" is activated to recognize that the moving speed of the front part of the machine body during turning of the agricultural tractor 14 becomes faster, and the vehicle speed becomes higher. If the "front wheel speed-increasing 4WD state D" is activated at this time, the moving speed of the front part of the machine body during turning of the agricultural tractor 14 becomes too fast, which increases the danger. However, when the steering angle of the front wheels 4 is detected by the steering angle sensor 11 and the steering angle does not exceed approximately 40 degrees on one side, the command of "front wheel speed-increasing 4WD state D" is regulated.

Here, "full turn control" and "small rudder angle turning control" will be briefly described.
As shown in FIG. 7, the rear wheel 3 of the front wheel 4 in the "rear wheel two-wheel drive state C" is set in the agricultural tractor 14 that has started to turn in the "rear wheel two-wheel drive state C" at the start time. The overrun rate for the rear wheel 3 is detected by the "detection mechanism E" to determine the efficiency of driving the rear wheel 3 to the ground.
When the efficiency of driving the vehicle to the ground is good, the vehicle is turned in the "rear wheel two-wheel drive state C" to reduce the damage on the field surface.

Here, the detection by the "detection mechanism E" will be described. First, the control command CP which is the "front wheel speed-increasing four-wheel drive state D" or "front and rear four-wheel drive state H" is sent to the control unit CP.
By "control means I" provided in U13, "front wheel speed-up 4WD state D" and "front and rear four-wheel drive state H" are stopped and control is changed to "rear wheel two-wheel drive state C". Next, "rear wheel 2WD state C"
As the front and rear wheels 4,
3 is detected and transmitted to the CPU 13 which is the control unit, and various data in the CPU 13 are used to detect the difference in rotational peripheral speed between the front and rear wheels according to the change in the steering angle of the steering wheel 28 from the rotational peripheral speed difference in a mere straight traveling state. For example, in a straight traveling state, if the front wheel 4 and the rear wheel 3 move at the same speed and there is no rotational peripheral speed difference between them, the rear wheel 3 which is the drive wheel surely drives the ground to the ground. Therefore, if the front wheel 4 is stopped and the rear wheel 3 is rotating, the rear wheel 3 judges that the ground slip is 100%, and vice versa. When the rotation peripheral speed of the front wheels 4 is faster than the rotation peripheral speed of the wheels 3, the rear wheels 3 are braking, or the vehicle is out of control at a speed higher than the driving speed of the rear wheels 3 on a steep downhill. It is judged that there is. Based on these judgments, the "control means I" in the control unit determines and commands the subsequent control.

In the illustrated example, the traveling speed of the machine is calculated from the rotation of the front and rear shafts, but the ground speeds of the front wheels 4 and the rear wheels 3 may be directly detected by a Doppler sensor type speedometer or the like. Further, when the "detection mechanism E" detects the overrun ratio of the front wheels 4 to the rear wheels 3 in the "rear wheel two-wheel drive state C", when it is determined that the efficiency of driving the rear wheels 3 with respect to the ground is low. , Turn on the full turn flag once and continue the turning operation in "front wheel speed-up 4WD state D" for about 1 second, then return to the turn in "rear wheel 2WD state C" and count the mark once to add.

Then, if the vehicle escapes from the mud land by turning in the "front wheel speed-increasing 4WD state D" for about 1 second,
When the agricultural tractor 14 turns in the "rear wheel two-wheel drive state C" and the mudland cannot be escaped and it is determined again that the efficiency of driving the rear wheel 3 to the ground is poor, the full turn flag is turned on again.
Then, the turning operation in the "front wheel speed-increasing 4WD state D" is repeated about 1 again.
After continuing for about a second, the state is returned to the "rear wheel two-wheel drive state C" and the mark count is re-added.

Until the count number of this mark exceeds the provisionally set three times, even if there is a control command of "front wheel speed-increasing 4WD state D", it is in the "front wheel speed-increasing 4WD state D" for a short time. As for the turning, the CPU 13, which is the control unit, determines whether or not the turning operation is possible in the "front wheel speed-increasing 4WD state D", and the control is changed. As shown in FIG. 8, the "small rudder angle turning control" determines whether the agricultural tractor 14 traveling in the "rear wheel two-wheel drive state C" determines the efficiency of driving the rear wheels 3 to the ground based on the presence or absence of slip, and When there is no slip of the wheels 3 on the ground, "rear wheel two-wheel drive state C"
By running as, the damage on the surface of the field is reduced.

When the slip is detected by the "detection mechanism E" in order to judge the efficiency of driving the rear wheels 3 to the ground in the "rear wheel two-wheel drive state C" by the presence or absence of the slip, there is a slip of the rear wheels 3. If it is determined that the 4WD flag is set to O once
After N, the vehicle is driven in the "front-rear four-wheel drive state H", and the control is changed to "slip control" described later. Regarding the "straight ahead control G", the control is divided into "slip control" or "brake control" depending on various conditions as shown in FIG. "Straight ahead control G" is the handle 2 of the agricultural tractor 14.
The control when the steering angle of No. 8 is equal to or less than "α" will be described in detail with reference to FIG. 10. First, when the control operation of the "slip control" shown in FIG. The slip of the rear wheel 3 is detected when the "rear wheel two-wheel drive state C" in which the "4WD flag" for instructing the "brake flag" and the "front and rear four-wheel drive state H" that are commands is not turned on, and the rear If there is a slip of 8% or more on the wheels 3 (when the rear wheels do not completely transmit the driving force to the ground).
A control is disclosed in which the 4WD flag is turned on and the first solenoid 59 is turned on to perform 4WD traveling in the "front-rear four-wheel drive state H". Next, as a case of immediately instructing the control operation of the "brake control" shown in FIG. 11, a case is disclosed in which the "brake flag" which is a command during brake operation is turned on and the "front and rear four-wheel drive state H" is instructed. Has been done. further,
As a command for control operation of "brake control",
When the "rear wheel two-wheel drive state C" in which the "brake flag" and the "4WD flag" are not turned on, the rear wheel 3 does not slip more than the temporarily determined 8% reduction by the detection of the "detection mechanism E" described later. If it is detected, the "detection mechanism E" detects whether the front wheels 4 are turning faster than the rear wheels 3, and the overrun rate of the front wheels 4 is increased by a predetermined 5%. Brake flag 7 when the value exceeds "A"
The case is disclosed in which 4 is turned on to set the "front-rear four-wheel drive state H".

In this way, the "straight ahead control G" is divided into two types of control, "slip control" and "brake control", and continues. Whether or not the "slip control" is to continue the "front and rear four-wheel drive state H" in the "slip control" in which the front and rear wheels 4, 3 are command-started at the same time as the "front and rear four-wheel drive state H" at substantially equal peripheral speeds. Is detected by the "detection mechanism E", and when the 4WD lock flag is ON, this "slip control" is immediately completed, and after a certain period of time, it becomes the control of "straight ahead control G". . The 4WD lock is a "front-rear four-wheel drive" in which the first solenoid 59 is turned on to actuate the direct coupling clutch 7 so that the front wheels 4 and 4 and the rear wheels 3 and 3 are always driven by four wheels at substantially the same peripheral speed. It is to drive in the "state H".

In the flowchart of FIG. 9, when the 4WD lock flag is not ON, it is judged whether or not the counting of the time "S" seconds (approximately 30 seconds) is started as a range for judgment, and if it is not counted, 30 seconds is counted. Start counting between. Next, it is determined whether or not the rear wheel 3 is slipping on the surface of the field, and if it is slipping, the vehicle travels in the "front and rear four-wheel drive state H" as it is. Since the control is started in the "driving state H", it is determined that the rear wheel 3 is not slipping, and the weight processing 7 for "R" seconds (approximately 2 seconds) is performed.
It is determined whether or not No. 2 is being processed, and if the wait process 72 is not being processed, the wait process for about 2 seconds is started.

When the "R" second wait processing is in progress, it is judged whether or not the control in the 4WD state has continued until approximately 2 seconds have elapsed, and when "R" seconds (2 seconds) have elapsed, " The number of drive changes between "2WD (rear wheel two-wheel drive state C)" and "4WD (front and rear four-wheel drive state H)" is used as a mark for one count addition 73, the 4WD flag is cleared, and the first solenoid 59 and the second Both the solenoids 60 are turned off and the vehicle runs in the "rear wheel two-wheel drive state C". During this running for about 30 seconds, the rotational speeds of the front and rear wheels 4 and 3 have a certain difference or more, and the 4W is again set.
It waits for a D (front and rear four-wheel drive state H) control instruction.

When the count of approximately 30 seconds has elapsed during traveling, the count of time "S" seconds (approximately 30 seconds) is cleared and the count number of drive change between "2WD and 4WD" is approximately 30 seconds. If it is determined that the count of drive changes between "2WD and 4WD" does not exceed the constant "M", it is determined between "2WD and 4WD". The drive change count is cleared, the "slip control" 71 is completed, and control such as the "straight ahead control G" described below is continued.

When it is determined that the drive change count between "2WD and 4WD" exceeds the constant "M", "2WD and 4W"
4WD while clearing the count of drive changes between "D"
Turn on the lock flag to complete the "slip control". 4
The WD lock control is continued for a fixed time. Next, the operation of "brake control" will be described with reference to the flowchart of FIG.

Although the control will be described later, the "brake control" 77 is a brake 76, 76 for the rear wheels 3, 3 when the driver suddenly brakes the agricultural tractor 14 while driving.
Is braking and the aircraft is about to stop, but the front wheels 4, 4
If both are not braked at the same time, the front wheels 4 side of the aircraft will proceed at the same traveling speed, and the brake 76 will be less effective, but this state will be automatically judged and the 4WD lock traveling will be performed instantaneously. Since the braking force of the wheels 3 also affects and acts on the front wheels 4 that are drivingly linked, the braking force is increased. When the 4WD lock flag is ON, this "brake control" is completed.

In FIG. 11, first, the time is "X" seconds (approximately 30 seconds).
(Second) is not counted, a count of approximately 30 seconds is started as a range for determination, and the overrun rate of the front wheels 4 is increased by a predetermined 5% during the time of this determination range. Although it is determined whether or not it has reached, as described above, when the "brake control" operation starts, the start is in "front-rear four-wheel drive state H" running, so at the first time there is no difference in rotation between the front and rear wheels 4,3. Does not happen.

In this case, the overrun rate of the front wheels 4 becomes equal to or less than the predetermined numerical value "A", and it is judged whether or not the wait processing for the time "Y" seconds (approximately 2 seconds) is being counted, and it is approximately 30.
Wait processing for about 2 seconds within the second determination range is started. This weighting process determines whether or not the control command has been issued during the "front and rear four-wheel drive state H" for about 2 seconds which is the time "Y", and there is a progress of the weighting process for about 2 seconds. If "2WD (rear wheel 2WD state C) and 4W
D (front and rear four-wheel drive state H) "is added once for the purpose of identifying the change of drive, clearing the 4WD flag and driving the agricultural tractor 14 with only the rear wheels 3, 3 It drives in "drive state C", and waits for an instruction to drive 4WD again during this 30-second counting run.

When the count of approximately 30 seconds has elapsed, "X"
The count of seconds is cleared, and it is determined whether or not the count number added as a mark for drive change between "2WD and 4WD" exceeds a constant "M" (probably 5 times). "2WD
When it is determined that the count of drive change between "4WD" and "4WD" has exceeded the constant "M" in 30 seconds which is "X" seconds,
The count of the drive change between "2WD and 4WD" is cleared, the 4WD lock flag is turned on for a predetermined time, the "brake control" 77 is completed, and the control in the "straight ahead control G" is performed.

When it is determined that the count value of the drive change between "2WD and 4WD" does not exceed the constant "M" in 30 seconds which is "X" seconds, the drive change between "2WD and 4WD" is performed. Clear the count number that is a mark and "brake control"
77 is completed and the above-described "straight ahead control G" is performed. In addition, as a side effect of "brake control", 2W
At the moment when the rear wheel 3 is in the "rear wheel two-wheel drive state C" in order to activate the "detection mechanism E" while the rear wheel 3 is traveling in the low speed shift state on the speed change mechanism 2 on a steep downhill during D running. Even when the vehicle is traveling at a speed higher than the traveling speed of the wheels due to slippery ground, the "detection mechanism E" detects the overrun of the front wheel 4 by the front and rear axis rotation sensors 10 and 9 and is a control means. The controller 13 controls 4WD immediately to prevent runaway.

Even on a flat ground, the detection of the operation of the "detection mechanism E" causes, for example, "2WD" even more than 6 times in 30 seconds.
In the case of traveling in which it is determined that the drive change count between “4WD” and “4WD” is activated, it is determined that the field is in a field in which many braking operations are performed by the driver, and the “front and rear four-wheel drive state H” is maintained to reduce the control movement. Increase the durability of the member. In other words, even if 4WD, which is the “front and rear four-wheel drive state H”, is instructed, if the front and rear axis rotation sensors 10 and 9 that are the “detection mechanism E” detect and it is determined that the instruction is not necessary, immediate control is performed. The vehicle automatically travels as 2WD by the controller 13 which is a means, and when a dangerous state is sensed by the front and rear axis rotation sensors 10 and 9 which are the "detection mechanism E" while instructing 2WD, a control means is automatically operated. 4 by the controller 13 which is
It is to switch to WD.

[0049]

As described above, according to the present invention, the detected value of each sensor is transmitted to the CPU 13 which is the control unit, the control means I selects a predetermined control from a plurality of control operations, and then each sensor is operated. When the detected value of is changed, the control can be switched to another control, so that the control operation can be performed quickly while having a large number of controls.

[Brief description of drawings]

 The figure shows an embodiment of the invention.

FIG. 1 is an explanatory diagram of a main part.

FIG. 2 is a side sectional view of a main part.

FIG. 3 is an overall side view.

FIG. 4 is a transmission plane diagram in which the whole is developed.

FIG. 5 is a flowchart of the entire automatic control.

FIG. 6 is a flowchart of a turning control F that is a subroutine.

FIG. 7 is a flowchart of full turn control, which is a subroutine.

FIG. 8 is a flowchart of a small steering angle turning control that is a subroutine.

FIG. 9 is a flowchart of slip control, which is a subroutine.

FIG. 10 is a flowchart of a straight ahead control G that is a subroutine.

FIG. 11 is a flowchart of brake control, which is a subroutine.

[Explanation of symbols]

 7 Direct-coupled clutch 8 Speed-up clutch 9 Rear-axis rotation sensor 10 Front-axis rotation sensor 11 Steering angle sensor 13 Control means C Rear-wheel two-wheel drive state D Front-wheel speed-up four-wheel drive state E Detection mechanism F Turning control G Straight-line control H Front-rear four-wheel Drive state I control means

Claims (3)

[Claims] 1. A mobile vehicle having a direct coupling clutch 7 and a speed increasing clutch 8 which are switchable between a "rear wheel two-wheel drive state C", a "front and rear four wheel drive state H" and a "front wheel speed increasing four-wheel drive state D". There
A rear axle rotation sensor 9, a front axle rotation sensor 10, and a steering angle sensor 11 are provided, and these sensors 9, 10,
The detection value of 11 is transmitted to the control unit 13. When the steering angle sensor 11 detects a steering angle equal to or larger than a predetermined value, the control is "turning control F", and the steering angle sensor 11 does not reach the steering angle equal to or larger than the predetermined value. "Control means I" for controlling "straight ahead control G" is provided, and after switching to "turning control F" by "control means I", "full turn control" is further performed according to a change in the detected value of the rear axle rotation sensor 9. Or a small wheel turning control, a front wheel rotation drive control device for a four-wheel drive type mobile vehicle. 2. A mobile vehicle having a direct coupling clutch 7 and a speed increasing clutch 8 which are switchable between a "rear wheel two-wheel drive state C", a "front and rear four wheel drive state H" and a "front wheel speed increasing four-wheel drive state D". There
A rear axle rotation sensor 9, a front axle rotation sensor 10, and a steering angle sensor 11 are provided, and these sensors 9, 10,
The detection value of 11 is transmitted to the control unit 13. When the steering angle sensor 11 detects a steering angle equal to or larger than a predetermined value, the control is "turning control F", and the steering angle sensor 11 does not reach the steering angle equal to or larger than the predetermined value. "Control means I" for controlling "straight ahead control G" is provided, and after switching to "turning control F" by "control means I", "full turn control" is further performed according to a change in the detected value of the steering angle sensor 11. Alternatively, a front wheel rotation drive control device for a four-wheel drive type mobile vehicle, characterized by switching to "small rudder angle turning control". 3. A moving vehicle having a direct coupling clutch 7 capable of switching between "rear wheel two-wheel drive state C" and "front and rear four-wheel drive state H", wherein a rear axle rotation sensor 9 and a front axle rotation sensor 1 are provided.
In the case where 0 is provided and the detection values of the sensors 9 and 10 are transmitted to the control unit 13, the rotational peripheral speeds of the front and rear axis rotation sensors 10 and 9 are measured while traveling in a "rear wheel two-wheel drive state C" for a short period of time. "Detection mechanism E" is provided to detect
When there is no change in the detection value of the front axle rotation sensor 10 due to the detection of, but the detection value of the rear axle rotation sensor 9 is below a predetermined value,
A front wheel rotation drive control device for a four-wheel drive type mobile vehicle, which is provided with "control means I" for switching on the direct coupling clutch 7 to switch to "front and rear four-wheel drive state H".