JP3221099B2 - Front wheel rotation drive control device for four-wheel drive mobile vehicle - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

2. Description of the Related Art Conventionally, a four-wheel drive vehicle turns off a front wheel when turning and turns with two rear wheels, and a two-wheel drive at the time of turning. There is a double-speed four-wheel drive at the time of turning in which the average peripheral speed of the front wheels is increased to about twice that of the rear wheels at the time of turning to make a turn.

As a method of controlling the double speed four-wheel drive at the time of turning, the turning is sensed by the steering angle of the steered wheel at the time of turning, and the automatic transmission is shifted to the speed increasing drive by the transmission provided in the front wheel drive system. Was.

[0004]

In such a conventional apparatus, only the mechanical control is performed by the steering angle of the steered wheels. The one having a total steering angle of about 60 degrees on one side operated the double-speed four-wheel drive at the time of turning by operating half (30 degrees) of the steered wheels.

[0005] Such a conventional device has no problem when used in a flat field such as a field or a field. However, when the vehicle travels on a road by itself to move to the field, the speed is increased in a hurry. When steering is performed during traveling, etc., double-speed four-wheel drive is activated during turning and the vehicle turns sharply. Therefore, a release switch and the operation of the switch are required to prevent danger. However, if the driver forgets the release operation or travels without releasing because it is troublesome, a sharp turn is likely to occur at the time of steering, and there is a danger of jumping out of the road or contacting other vehicles.

[0006]

SUMMARY OF THE INVENTION The present invention is to solve such a problem of the conventional device, and has taken the following technical means. That is, engine 1
Is transmitted to the rear wheels 3 and the front wheels 4 via the multi-stage transmission mechanism 2 and the rear wheels between the transmission mechanism 2 and the rear wheels 3 in a four-wheel drive path in which the front wheels 4 are steered wheels. The direct drive clutch 5 is interlocked to the front wheel 4 via a front drive shaft 6, and the direct drive clutch 7 is connected to the front drive shaft 6 to turn on and off the rear wheel drive shaft 5, and the front drive shaft 6 is connected to the rear wheel 6. A speed-increasing clutch 8 is provided for speeding up and off the direct proportional drive rotation 5 by about twice, and furthermore, the steering angle sensor 11 for measuring the steering angle of the front wheel 4 and the left and right rear wheels 3, 3 are separately braked. A brake sensor 78 for measuring the operation of the brake petal 77 is provided, and the connection operation of either the direct coupling clutch 7 or the speed increasing clutch 8 is controlled by detecting the operation of the steering angle sensor 11 at a predetermined “β” degree. In the one, the braking sensor 7 The operation of the four-wheel drive type mobile vehicle is characterized in that when the steering angle of the steering angle sensor 11 is detected to be smaller than a predetermined angle [α], the connection operation of the speed increasing clutch 8 is controlled. The configuration of the front wheel rotation drive control device was adopted.

[0007]

According to the present invention, the following technical effects can be obtained by the above configuration. That is, if the predetermined steering angle “β” degree is set to an angle close to full steering, the safety release switch at the time of traveling on the road can be abolished, and when the driver makes a sharp turn in the field, unconsciously Since one of the rear wheels 3 is braked, at the time of this braking operation, the double-speed four-wheel drive at the time of turning, in which the front wheel is accelerated, is operated at a steering angle of "α" degree which is equal to or less than a predetermined value. It is possible to drive safely using the subconscious.

[0008]

Embodiments of the present invention will be described below in detail with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements and the like of the components described in this embodiment are as follows:
Unless there is a particular description, the scope of the present invention is not intended to limit the scope of the present invention only to them, but is merely an illustrative example.

The illustrated example is an agricultural tractor 14 in which the present invention is folded into a front wheel 4, 4 drive unit of the agricultural tractor 14. A front-rear four-wheel drive mobile vehicle that is an agricultural tractor 14 has front and rear wheels 4, 4, 3, and 3 attached to the four front and rear corners of the body, and is driven using the power of the engine 1.

The front and rear wheels 4, 4, 3, 3 are connected to front and rear axle cases 15, 16, respectively, and protrude outwardly. 18 and so on. The rear end of the front frame 17 is a machine frame integrally attached to the main frame side,
The engine 1 is detachably attached to a front portion of a front frame 17 which is a machine frame.

The center portion of the front axle case 15 in the left-right direction is pivotally mounted 19 on the front frame 17 so as to be able to swing left and right, and the front wheels 4, 4 move up and down due to unevenness of the ground. A front differential device 20 for adjusting the peripheral speed difference between the left and right front wheels 4 and 4 is provided at the center in the left-right direction of the front axle case 15, and a front drive projecting from a transmission case 21 to be described later to the outside. Input via axis 6.

A radiator 22 and a cooling fan 23 are disposed in front of the engine 1. Reference numeral 12 denotes an engine rotation sensor, which is provided near the cooling fan 23 in the illustrated example and measures the number of revolutions of the engine 1. However, if the engine 1 is rotating in direct proportion to the engine 1, a crankshaft (not shown), You may read the rotation of other rotating parts.

A hood 24 covers the front and sides of the engine 1 and accessories (not shown). Reference numeral 26 denotes a clutch housing, in which a main clutch 27 is mounted, which is attached to a rear portion of the engine 1 and transmits a driving force to a rear transmission case 21 portion.

Reference numeral 28 is a handle, and 29 is a handle post. The lower end of the handle post 29 is attached to the machine frame. When the handle 28 is rotated left and right, it protrudes from the power steering case 65 disposed in the front frame 17. The rotating shaft 66 is rotated via a transmission shaft connected to the handle 28, whereby the pitman arm 67 is swung left and right by receiving the assisting force of hydraulic pressure, and the knuckle arm 68 integrated with the front wheel 4 is moved by the pitman rod 64. Push-pull steering is performed, and the front wheels 4, 4 connected left and right by the tie rod 69 are steered left and right.

A steering angle sensor 11 shown in FIGS. 3, 4 and 6 is attached to a mounting frame 72 on the outer periphery of the power steering case 65, and measures the swing angle of the pitman arm 67 via a connecting metal 71. Thus, the steering angle of the front wheels 4 is calculated, and the potentiometer reads the resistance change due to the rotation of the shaft 70 as the electric resistance. The central shaft 73 of the connecting metal member 71 is swingably attached to the mounting frame 72, and a swinging operating pin 67 a projecting from the pitman arm 67 rocks the long hole of the connecting metal member 71.

The tip swing pin 71a of the connecting metal fitting 71 swings left and right through the tip slit of the swing arm 74 fixed to the shaft 70 of the steering angle sensor 11. The steering angle sensor 11 is
Mechanically, it moves about 150 degrees from point A to point E, and points C to D within the range of the movement are electrically extracted as voltage changes as shown in FIG.

The forward direction F of the front wheel 4 when the handle 28 is in the forward state is determined by dividing the range between the points C and D into approximately two equal parts.
The voltage position (forward direction) of the steering angle sensor 11 at the time of neutral according to the above, and the voltage change positions of the angles θ, β, α are respectively taken right and left from the point B. Describing the steering angle of the front wheels 4, if the steering wheel 28 is fully moved to the left or right from the forward direction F, there is a limit that no further change occurs due to the mechanical dimensions of the links and rods. For the forward direction "F", the wheel angle "?"
1 ", which is about 60 degrees for a normal agricultural tractor.

The wheel angle "β1" up to the predetermined steering is close to the wheel angle "θ1" of the full steering, and is set to about 55 degrees. The wheel angle “α1” of the steering that is equal to or less than a predetermined value is set to about 40 degrees. The voltage change of the steering angle sensor 11 is transmitted to the controller 13 via the wiring 62 and used as data for each control.

The operation of the detection angles θ, β, α of the steering angle sensor 11 and the operation of the wheel angles θ1, β1, α1 of the front wheels 4 are as follows.
Only by reading the movement of the same portion at another position, it operates at the same angle ratio, and it is possible to detect at the same angle considering the length of the links. Fenders 30, 30 are attached from the front of the left and right rear wheels 3, 3 to the upper side,
A seat 31 is provided between the left and right fenders 30, 30.

The left and right rear wheels 3, 3 are connected to each other by a rear axle case 16, and a rear differential device 25 is provided at an intermediate portion between the left and right wheels. The gear case 18 containing the rear differential device 25 is attached to the rear part of the transmission case 21 described above, and the transmission case 21 is integrally connected to the rear end of the clutch housing 26.

A substantially flat floor 3 extends from the driver's feet under the seat 31 to both sides under the handle post 29.
2 is installed. The floor 32 is substantially flat in the left-right direction and has an outer width up to the vicinity of the outer edges of the left and right fenders 30, that is, a width close to the entire body width. Engine 1
The driving force that has passed through the main clutch 27 is input from the front of the transmission case 21.

Although not shown in detail, the input driving force is transmitted through a transmission mechanism 2 including a part or all of a reversing device 33, a main transmission device 34, an auxiliary transmission device 35, etc., which perform forward / reverse shifting, and a rear differential. The system is divided into two systems: a traveling wheel drive system that reaches the device 25, and a PTO drive system 36 that is an external power takeoff that is transmitted and 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 shafts to various working machines (not shown) can be detachably attached to the projecting portions. Output shafts 75, 75 project right and left from the rear differential device 25, and right and left rear wheels 3, 3 are attached to the rear of a transmission path provided with left and right brakes 76, 76 at an intermediate portion of the output shaft 75.

The left and right rear wheels 3, 3 are individually or simultaneously braked by independent left and right brake petals 77a, 77b, respectively. The braking operation of the brake petal 77 is performed by left and right separate brake sensors 78a, 78b. To sense. In the illustrated example, the brake sensors 78a and 78b are contact switches below the brake petals 77a and 77b. However, a rotation sensor is attached to the output shaft 75 or the vicinity of the rear wheel 3 to read the rotation speed and stop or rotate the rotation unit. The deceleration fluctuation value may be used.

Any drive shaft may be used between the output from the transmission mechanism 2 and the input to the rear differential device 25.
The driving force of the rear-wheel directly-proportional driving rotation unit, which is the driving shaft, is transmitted to the main gear 40 via the output gear 38 and the counter gear 39. The main gear 40 is the first clutch boss 4
1 and engages with the boss and rotates integrally with the boss.

Further, another auxiliary gear 42 is attached by engaging with the spline portion, and the main and auxiliary gears 40 and 42 rotate simultaneously. These are two gears in the figure example,
If there is no problem in the number of teeth, the main and sub gears 40 and 42 may be one. The auxiliary gear 42 has a counter entrance gear 43
Are always engaged with each other, and the counter outlet gear 45 connected by the connecting drive shaft 44 is also integrally rotatable.

The counter outlet gear 45 is always meshed with the second clutch gear 46, and can simultaneously rotate to the second clutch boss 47 integrated with the second clutch gear 46. In other words, when the main gear 40 rotates, the first clutch boss 41 and the second clutch boss 47 provided on the front drive clutch shaft 48 so as to freely rotate and rotate simultaneously, and when the main gear 40 stops, the first clutch boss 41 and the second clutch boss 47 rotate. The first and second clutch bosses 41 and 47 are simultaneously stopped.

Since the speed of the counter inlet gear 43 is increased by the auxiliary gear 42 and the speed of the second clutch gear 46 is increased by the counter outlet gear 45, when the first clutch boss 41 makes one rotation, the second clutch boss 41 is rotated. 4
7 rotates approximately twice. These first and second clutch bosses 4
The first piston 49 and the second piston 50 are located between
Are arranged, and the outer periphery is covered with a drive drum 52 having a plurality of friction plates 51, 51 therein.

The drive drum 52 is partitioned forward and backward by a partition wall 53, and the first clutch boss 41 at the rear and the friction plate 5
1 and the first piston 49 constitute the direct coupling clutch 7, and the second clutch boss 47 at the front, the friction plate 51, and the second piston 5
0 constitutes the speed increasing clutch 8. Drive drum 52
Are integrated with the spline portion of the front drive clutch shaft 48.

A lubricating oil 54 is held in the transmission case 21 to lubricate each transmission gear and shafts. This lubricating oil 54
Is sucked and pressurized by an oil pump 55, and a first oil chamber 56 between the first piston 49 of the direct coupling clutch 7 and the partition wall 53 via an oil passage switching valve 58, or a speed increasing clutch. 8 to the second oil chamber 57 between the second piston 50 and the partition wall 53.

The oil passage switching valve 58 shown in FIG. 2 shows a neutral state. Next, when the first solenoid 59 is energized, the valve is switched to the valve 58a, high-pressure oil flows into the first oil chamber 56, and the direct coupling clutch 7 Thus, the rear wheel direct proportional drive rotation 5 is transmitted to the front drive clutch shaft 48 as it is. When the second solenoid 60 is energized, the valve is switched to the valve 58b, high-pressure oil flows into the second oil chamber 57, the speed-increasing clutch 8 is connected, and the rear wheel direct proportional drive rotation 5 is approximately doubled to the front drive clutch shaft 48. Tell

The rear wheel direct drive rotation 5 input to the front drive clutch shaft 48 is linked to the front drive shaft 6 described above and drives the front wheels 4 and 4 via the front differential device 20. Reference numeral 61 denotes a drain oil passage, which releases pressure oil in the oil passage associated with the transmission case 21 when the oil passage switching valve 58 is switched.

In the illustrated example, the transmission case 21 is used as an oil reservoir, but a separate oil tank may be provided for exclusive use. A rear shaft rotation sensor 9 is provided near the counter outlet gear 45, and a front shaft rotation sensor 10 is provided near the drive drum 52, and reads the number of rotations of each rotating unit.

Next, the control will be described with reference to a flowchart. The main part of the present invention will be described with reference to FIG.
When the steering wheel 28 in the straight traveling state is steered left or right, and the steering angle sensor 11 notifies the controller 13 that the steering angle of the front wheel 4 exceeds a predetermined steering angle “β”,
The front wheel speed-up control is started, and the driving force via the speed-increasing clutch 8 rotates the front wheels 4 at a peripheral speed of about twice and facilitates turning.

Even if the steering angle sensor 11 for measuring the steering angle of the front wheels 4 does not exceed the predetermined steering angle "β", the steering angle exceeds the predetermined steering angle "α", and the operation of the one-side brake is completed. When the braking sensor 78 informs the controller 13 that the braking has been performed, the front wheel speed-up control is started, and the driving force via the speed increasing clutch 8 rotates the front wheel 4 at a peripheral speed of about twice and facilitates turning. I do.

One-brake braking and two-brake braking are determined based on whether the left and right brake sensors 78a, 78b have been operated one way or both. One-brake braking aims to make a quick turn, and usually involves steering the steering wheel to the left or right, and two-brake braking aims to stop the aircraft in place. If all are NO, the front wheel drive control is the normal control.

The normal control includes two-wheel drive running after the driving force to the front wheels 4 is cut off and a four-wheel drive lock state in which the front wheels 4 are driven via the direct coupling clutch 7 and the front drive shaft 6. Yes, although not described in detail, automatic switching is performed under the following conditions. When turning, if the front wheel steering angle is equal to or less than "α" and there is no one-brake operation, the vehicle turns with rear two-wheel drive. The rotation of the shaft rotation sensor 10 decreases proportionally, whereas the rotation of the rear shaft rotation sensor 9
As long as is turning, the degree of slip is known. ) The direct coupling clutch 7 is connected, the vehicle turns with the driving force of the front wheels 4, the slip is measured again, and the vehicle is driven while judging whether the rear two-wheel drive or the four-wheel drive lock is good.

The flowchart shown in FIG. 9 is another embodiment, in which the speed of change of the steering angle sensor 11 is detected, and when the steering angle exceeds the angle “α” and is equal to or less than “β”, the steering speed is changed. Is greater than or equal to a predetermined value, the front wheel speed-up control is started, and the sudden operation of the steering wheel is measured instead of the one-side brake operation. The determination 80 of the steering speed is based on the steering angle sensor 11 with the timer count number 79 per fixed time.
Is determined by measuring the voltage change of

[Brief description of the drawings]

 The figure shows an embodiment of the present invention.

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

FIG. 2 is an explanatory diagram of a transmission system of the entire main part.

FIG. 3 is a plan view of a main part around a front wheel.

FIG. 4 is a rear cross-sectional view of a main part, which is a cross section SS in FIG. 3;

FIG. 5 is a side sectional view in which a clutch part of a main part is enlarged.

FIG. 6 is a plan view of a steering angle sensor.

FIG. 7 is an explanatory diagram of electrical operation of a steering angle sensor.

FIG. 8 is a flowchart of main part control.

FIG. 9 is a flowchart of another main part control.

FIG. 10 is an overall side view.

[Description of Signs] 1 Engine 2 Transmission mechanism 3 Rear wheel 4 Front wheel 5 Rear wheel direct proportional drive rotation 6 Front drive shaft 7 Direct connection clutch 8 Speed increasing clutch 11 Steering angle sensor 77 Brake petal 78 Brake sensor

Claims (1)

(57) [Claims] 1. A driving force of an engine (1) is transmitted to a rear wheel (3) and a front wheel (4) via a plurality of speed change mechanisms (2), and the front wheel (4) is used as a steering wheel. In the four-wheel drive path, the rear wheel direct proportional drive rotation (5) between the transmission mechanism (2) and the rear wheel (3) is interlocked to the front wheel (4) via the front drive shaft (6). A direct coupling clutch (7) for turning on / off the rear wheel direct proportional drive rotation (5) in the drive shaft (6) and a rear wheel direct proportional drive rotation (5) in the front drive shaft (6) portion about twice as fast. A speed increasing clutch (8) for turning on and off, a steering angle sensor (11) for measuring a steering angle of a front wheel (4), and a brake petal (77) for separately braking left and right rear wheels (3, 3) are provided. A braking sensor (78) for measuring the operation of the steering wheel, and a steering angle sensor (11)
The operation of the braking sensor (78) is detected in the connection operation control of either the direct coupling clutch (7) or the speed increasing clutch (8) by sensing the operation at a steering angle of a predetermined "β" degree. In this case, the connection operation of the speed-increasing clutch (8) is controlled by sensing the operation of the steering angle of the steering angle sensor (11) at a predetermined angle α or less, and the front wheel rotation of the four-wheel drive mobile vehicle is characterized in that Drive control device.