JP2000025484A - Work travel vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make an intentional returning action to the two-wheel drive state unnecessary by providing a four-wheel drive temporary return means temporarily returning to the four-wheel drive state while the prescribed operation tool is operated in the two-wheel drive state. SOLUTION: A temporary return pedal 49 is integrally provided on a pedal plate 46 connected to second connecting rods 40L, 40R via a connecting member 47 or the like so that the second connecting rods 40L, 40R can be independently rotated by the action of the temporary return pedal 49. When the temporary return pedal 49 is depressed in the two-wheel drive state locking a drive switching lever 42 on a front lock groove 45a, the second connecting rods 40L, 40R are set to the nontensile state, and the travel drive state is temporarily returned to the four-wheel drive state. When a foot is released from the temporary return pedal 49, the second connecting rods 40L, 40R are pulled by a coil spring 48, and the two-wheel drive state is again maintained. No returning action to the two-wheel drive state is required, and the travel drive state can be temporarily returned to the four-wheel drive state easily.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention belongs to the technical field of working vehicles such as riding rice transplanters.

[0002]

2. Description of the Related Art In general, a traveling vehicle of this type includes a four-wheel drive type traveling power transmission mechanism for driving front wheels and rear wheels, and switches the driving method to two-wheel drive. Some vehicles are provided with two-wheel drive switching means. And while such a traveling vehicle for work secures the ability to travel on rough roads during work traveling based on four-wheel drive,
When traveling on the road, there is an advantage that switching to two-wheel drive can give priority to fuel efficiency and circulating performance.

[0003]

By the way, even on a road, when the vehicle climbs a steep slope or escapes from mud, it is required to temporarily switch to four-wheel drive. Since it is necessary to switch to the two-wheel drive again, the operation is not allowed to be complicated, and there is a disadvantage that the operation to return to the two-wheel drive is forgotten and the fuel efficiency and the circulating performance are reduced.

[0004]

SUMMARY OF THE INVENTION The present invention has been made to solve these problems in view of the above-mentioned circumstances, and is a four-wheel drive system for driving front wheels and rear wheels. A work traveling vehicle having a power transmission mechanism and a two-wheel drive switching means for switching the driving method to two-wheel drive in the traveling power transmission mechanism, wherein the work traveling vehicle has a predetermined two-wheel drive switching state. Four-wheel drive temporary return means for temporarily returning to the four-wheel drive state while the operating tool is being operated is provided. In other words, since the vehicle is returned to the four-wheel drive only while the predetermined operating tool is being operated, there is no need to consciously perform the operation for returning to the two-wheel drive. The inconvenience of deteriorating the fuel efficiency and running performance during traveling can also be eliminated. In addition, the four-wheel drive temporary return means,
While a predetermined foot pedal is being depressed in the two-wheel drive switching state, the vehicle is temporarily returned to the four-wheel drive state. In other words, it is possible to temporarily return to four-wheel drive by depressing the foot pedal,
There is no inconvenience that hinders the steering operation and shifting operation performed by hand.

[0005]

Next, a first embodiment of the present invention will be described with reference to the drawings. In the drawings, reference numeral 1 denotes a four-wheel-drive traveling machine (riding rice transplanter).
The engine 2 and the transmission case 3 are mounted on the front part of the vehicle, while the planting part 5 is connected to the rear part of the body via a lifting link mechanism 4. The power of the engine 2 is transmitted to the planting section 5, the front wheel 6, the rear wheel 7 and the like after being shifted in the transmission case 3, and these basic configurations are all conventional.

Reference numeral 8 denotes a rear axle case for transmitting power to the left and right rear wheels 7.
An input shaft 9, first to sixth transmission shafts 10 to 15, left and right final shafts 16L and 16R, a front wheel braking clutch 17, left and right side clutches 18L and 18R, left and right side brakes 19L and 19R, etc. are installed. I have. The power transmitted from the transmission case 3 to the input shaft 9 via the traveling PTO shaft 20 is applied to the bevel gears 9a and 9a.
After being transmitted to the first transmission shaft 10 via the first transmission shaft 0a, the second transmission shaft 11, the right side clutch 18R, the right side brake 19R, the third transmission shaft 12, the fourth transmission shaft 13, the right final shaft 16R, etc. And transmitted to the right rear wheel 7R, the front wheel braking clutch 17, the left side clutch 18L, the left side brake 19L, the fifth transmission shaft 14,
The power is transmitted to the left rear wheel 7L via the sixth transmission shaft 15, the left final shaft 16L, and the like. By the way,
When the main clutch 21 is operated to the disengagement side to stop running, the front wheel braking clutch 17 directly connects the fifth transmission shaft 14 and the first transmission shaft 10 without passing through the left side clutch 18L, Left side brake 19L
Is transmitted to the front wheels 6 via the traveling PTO shaft 20.

[0007] Reference numerals 22 and 23 denote the side clutch 18.
(L, R), the spline grooves formed on the outer peripheral surface of the cylindrical shaft 22 are integrally rotated around the axis, While a plurality of movable drive-side disks 24 are fitted, spline grooves formed on the inner peripheral surface of the clutch case 23 have:
A plurality of driven-side disks 25 that rotate integrally in the direction around the axis and are movable in the axial direction are fitted. The drive-side disk 24 and the driven-side disk 25 alternately overlapped in the axial direction are locked by a retaining ring 26 fitted on the inner peripheral surface of the clutch case 23 and an outer end of the cylindrical shaft 22. A plurality of disc springs 28 interposed between the outer surface of the spacer 27 and the inner surface of the clutch case 23 cause the clutch case 23 to move outward (inward).
, The retaining ring 26 normally presses the drive-side disk 24 and the driven-side disk 25, and the cylindrical shaft 22 and the clutch case 23 are integrally formed based on the frictional force generated between the two disks. When the clutch case 23 is moved inward (cut side) against the disc spring 28 while rotating,
The power transmission between the cylindrical shaft 22 and the clutch case 23 is cut off when the pressure of the retaining ring 26 is loosened.

The boss portion 23a of the clutch case 23 extends outward, and the side brake 19 is provided between an outer peripheral surface of an intermediate portion of the extended boss portion 23a and an inner peripheral surface of the rear axle case 8. Is configured. That is, a plurality of brake disks 29 that rotate integrally in the axial direction and are movable in the axial direction are fitted into the spline grooves formed on the outer peripheral surface of the boss portion 23a, while the rear axle case. A plurality of friction plates 30 whose rotation around the axis is restricted and which is movable in the axial direction are fitted in the spline grooves formed on the inner peripheral surface of the inner peripheral surface 8. Then, the brake disk 29 and the friction plate 30 alternately overlapped in the axial direction.
When a brake operation force, which will be described later, is received from the outside, it is pressed against the inner surface of the rear axle case 8 to generate a frictional force, and the rotation of the clutch case 23 is braked based on the frictional force. . Incidentally, reference numeral 31 denotes a disc spring for returning the side brake.

Reference numeral 32 denotes an operating boss which is externally fitted to the outer peripheral surface of the distal end portion of the boss portion 23a via a pair of bearing members 33. The operating boss 32 receives a shifter operating force described later and moves inward. When moved, the clutch case 23 is pressed inward to operate the side clutch 18 to the disengagement side, and the brake disk 29 and the friction plate 30 are pressed to operate the side brake 19 to the braking side. In order to operate the side brake 19 after the side clutch 18 is disengaged, there is a neutral operation range in which only the side clutch 18 is disengaged, and the rear wheel 7 freely rotates in this neutral operation range.

Reference numeral 34 denotes a shifter shaft rotatably supported on the upper outside of the rear axle case 8.
A shifter pin 34a located on the outer side surface of the operation boss 32 is fixed to a lower end of the shift boss 32 via a shifter arm 34b, while a clutch arm 35 is integrally connected to an upper end of the shifter shaft 34. I have. When the clutch arm 35 is pulled forward, the shifter pin 34a presses the operating boss 32 inward, and the side clutch 18 and the side brake 19 are operated as described above.

Reference numeral 36 denotes a pair of left and right side brake pedals (side clutch pedals) disposed on the operation unit. Of the pedals 36, a left pedal 36 L is integrally connected to a pedal shaft 37. While the right pedal 36
R is rotatably supported by the pedal shaft 37. When the left pedal 36L is depressed, the left operating arm 38L provided at the left end of the pedal shaft 37 is connected to the left clutch arm 35L via the first connecting rod 39L.
On the other hand, when the right pedal 36R is depressed, the right operating arm 38R provided on the boss of the right pedal 36R pulls the right clutch arm 35R via the first connecting rod 39R. Incidentally, 36
Reference numeral a denotes a connecting plate for connecting the left and right pedals 36L and 36R when traveling on a road or the like.

40L and 40R are the first connecting rods 39.
L, 39R and a pair of left and right second connecting rods, the rear end of the left second connecting rod 40L among the second connecting rods 40L, 40R.
L, the rear end of the right second connecting rod 40R is connected to the right clutch arm 35R, but the front ends of the second connecting rods 40L, 40R are connected to each other via the connecting pin 40a. If the connecting portion is pulled forward by a predetermined stroke, the left and right clutch arms 35L and 35R can be simultaneously neutralized. In this state, the left and right side clutches 18L and 18R are simultaneously disengaged and the left and right rear wheels 7
, The driving state of the traveling body 1 of the four-wheel drive system can be switched to the two-wheel drive state (front-wheel drive state).

41L and 41R are second connecting rods 40L,
A coil spring (brake operation permitting means) interposed between the clutch arm 35R and the clutch arm 35L, respectively. The coil springs 41L and 41R are independent of the operation state of the second connecting rods 40L and 40R. 36
Clutch arm 35L, 35R with operation of L, 36R
Is allowed to rotate forward. That is,
In the four-wheel drive state in which the second connecting rods 40L, 40R are not pulled, the disengagement operation of the side clutches 18L, 18R and the brake operation of the side brakes 19L, 19R based on the operation of the pedals 36L, 36R are allowed. Even in the two-wheel drive state in which the second connecting rods 40L, 40R are pulled, the brake operation of the side brakes 19L, 19R based on the operation of the pedals 36L, 36R is allowed.

Reference numeral 42 denotes a drive switching lever (two-wheel drive switching means) provided on the operation unit.
Are provided so as to be integrally rotatable on a lever plate 44 which is rotatable back and forth with the support shaft 43 as a fulcrum, and a position where the lever guide 45 is locked in the front lever locking groove 45a, The lever plate 44 is operable to be locked to the position 45b, but the lever plate 44 is connected to the connection pin 40a via a pedal plate 46 and a connection member 47 (connection wire, connection link, etc.) to be described later. . That is, when the drive switching lever 42 is locked in the rear locking groove 45b, the second connecting rods 40L and 40R can be held in a non-tension state, while the drive switching lever 4
2 is locked in the front locking groove 45a, the second connecting rods 40L and 40R can be held in a tensioned state. As a result, the four-wheel drive state is set based on the operation of the drive switching lever 42. Switching to a two-wheel drive state can be performed.

The pedal plate 46 is supported rotatably back and forth with the support shaft 43 as a fulcrum, similarly to the lever plate 44, and the lever plate is biased by a coil spring 48 interposed between the plates 44 and 46. Because it is in contact with the stopper portion 44a of the lever 44, it always rotates integrally with the lever plate 44, but when the temporary return pedal 49 provided integrally with the pedal plate 46 is operated, the coil spring 48 Are independently rotated against the biasing force of That is, in the two-wheel drive state in which the drive switching lever 42 is locked in the front locking groove 45a, when the temporary return pedal 49 is depressed, the second connecting rods 40L, 40R become non-tensile and travel. While temporarily returning the drive state to the four-wheel drive state, releasing the temporary return pedal 49 releases the second connecting rod 40.
L and 40R are pulled by the coil spring 48 to maintain the two-wheel drive state again.

In the present embodiment, the lever plate 44 is constituted by two independently rotatable plate members 44A and 44B.
4A, the drive switching lever 42 is provided, and the other plate member 44B is provided with a stopper 44a and a coil spring 48.
Is provided. Normally, the two plate members 44A and 44B are integrated by the through pin 54. However, since the through pin 54 can be inserted and removed according to the operation of the drive switching release lever 55, the drive switching release lever 55 When the through pin 54 is pulled out based on the operation of
4A and 44B are independently rotated, and as a result, the four-wheel / two-wheel drive switching based on the operation of the drive switching lever 42 is continuously released.

In the vehicle constructed as described above, when traveling on the road, the vehicle is continuously driven in the two-wheel drive state while holding the drive switching lever 42 at the two-wheel drive position. By simply depressing the return pedal 49, the vehicle temporarily returns to the four-wheel drive state, and if the temporary release pedal 49 is released, the two-wheel drive state is resumed. That is, since it is not necessary to perform an operation for returning to the two-wheel drive state as in the case of temporarily returning to the four-wheel drive state by operating the drive switching lever 42, the operation for temporarily returning to the four-wheel drive state is performed. Is easier, and
It is also possible to eliminate the inconvenience of forgetting the operation of returning to the two-wheel drive state and deteriorating the fuel efficiency and running performance when traveling on the road.

As the operating tool for temporarily returning to the four-wheel drive state, any operating tool can be used as long as it is a non-residual type (automatic reset type) operating tool.
In the present embodiment, since the foot pedal (temporary return pedal 49) is employed, there is no inconvenience that the steering operation and the shifting operation performed by hand are hindered.

The present invention is, of course, not limited to the above-described embodiment. For example, as in a second embodiment shown in FIGS. 6 to 8, the side clutch 50 and the side brake 51 are independent. The present invention can be implemented with substantially the same configuration, even when the clutch arm 52 and the brake arm 53 are connected outside the case.

Further, it is needless to say that the two-wheel drive switching means is not limited to the one using the side clutch. For example, the present invention can be applied to a work vehicle having no side clutch as shown in FIG. can do. That is, the working vehicle of the third embodiment shown in FIG. 9 employs a rear wheel differential system in which a rear wheel differential mechanism 56 is interposed in a rear wheel power transmission path. If the two-wheel drive switching clutch 57 provided on the upper side of 56 is configured to be turned on and off according to the operation of the drive switching lever 42 and the temporary return pedal 49 described above, substantially the same operation and effect as in the first embodiment can be obtained. be able to.

[Brief description of the drawings]

FIG. 1 is a side view of a riding rice transplanter.

FIG. 2 is an expanded sectional view of a transmission case, a front axle case, and a rear axle case.

FIG. 3 is a sectional view of a main part of a rear axle case showing a side clutch and a side brake.

FIG. 4 is a sectional view of a main part of the same showing a shifter shaft.

FIG. 5 is a schematic plan view showing a two-wheel drive switching mechanism and a pedal operating mechanism.

FIG. 6 is a sectional view of a main part of a rear axle case showing a second embodiment.

FIG. 7 is a schematic plan view showing a pedal operation mechanism according to a second embodiment.

FIG. 8 is a schematic side view of the same.

FIG. 9 is a power transmission circuit diagram showing a third embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Running body 6 Front wheel 7 Rear wheel 18 Side clutch 19 Side brake 35 Clutch arm 36 Pedal 39 First connecting rod 40 Second connecting rod 41 Coil spring 42 Drive switching lever 49 Temporary return pedal

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2B062 AA02 AB01 BA11 BA43 2B063 AA02 AB01 AB08 BA22 CA21 3D036 GA16 GA45 GB05 GD05 GD07 GH16 GJ12 GJ17 3D043 AA04 AB11 AB17 EA02 EA18 EA44 EA45 EB02 EB05 EB05 EB05

Claims (2)

[Claims] 1. A work vehicle having a four-wheel drive traveling power transmission mechanism for driving front wheels and rear wheels, and having two-wheel drive switching means for switching the driving method to two-wheel drive in the traveling power transmission mechanism. Wherein the working vehicle is
A work vehicle having a four-wheel drive temporary return means for temporarily returning to a four-wheel drive state while a predetermined operating tool is being operated in a two-wheel drive switching state. 2. The four-wheel drive temporary return means according to claim 1, wherein the two-wheel drive switching state temporarily returns to the four-wheel drive state while a predetermined foot pedal is being depressed. Work traveling vehicle.