JPH1199957A - Travelling vehicle for working - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent frequent maintenance and to prevent change-over inability of a front wheel forced operating mechanism by internally mounting a front wheel forced operating mechanism and an automatic changeover operating mechanism in a transmission case, and interlockingly connecting the automatic changeover operating mechanism to a steering mechanism in the transmission case. SOLUTION: A front wheel forced operating mechanism forcedly generating rotational difference between right and left front wheels is provided, and an automatic changeover operating mechanism 55 interlocking with the turning operation of a steering wheel to automatically change to the forced operating condition is provided. The front wheel forced operating mechanism and the automatic changeover operating mechanism 55 are internally mounted in a transmission case 4, the automatic changeover operating mechanism 55 is interlockingly connected to a steering reduction gear mechanism 42 in the transmission case 4, hence trouble such as deformation and breakage of the automatic changeover operating mechanism 55 is eliminated, dispensing with cleaning or greasing to improve maintenaceability, and trouble of changeover inability of the front wheel forced operating mechanism can be dissolved.

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 Generally, a working vehicle for driving front wheels is provided with a differential mechanism (differential mechanism) for generating a rotational difference between left and right front wheels in accordance with driving resistance. The dynamic mechanism transmits a large amount of rotational force to the front wheel on the side with lower driving resistance, so if the front wheel on the outer wheel slips during the turning of the body, the front wheel on the inner wheel side with higher driving resistance stops, preventing smooth turning. May be Therefore, a front wheel forced differential mechanism for forcibly generating a rotation difference corresponding to the body turning between the left and right front wheels is provided, and the front wheel forced differential mechanism is automatically shifted in conjunction with the body turning operation. Things have been proposed in the past.

[0003]

However, in the prior art, when the front wheel forced differential mechanism is connected to the steering mechanism in an interlocking manner, the connecting mechanism (automatic switching operation mechanism) is disposed below the transmission case. The exposed coupling mechanism may be entangled with grass, or the coupling mechanism may be deformed or damaged by contact with obstacles.As a result, frequent maintenance such as cleaning and lubrication is not possible, There was a possibility that the front wheel forced differential mechanism could not be switched based on deformation or breakage of the coupling mechanism.

[0004]

SUMMARY OF THE INVENTION In view of the above circumstances, the present invention has been made to solve these problems, and is directed to a steering mechanism for steering a front wheel according to an operation of a steering wheel. And a front wheel forced differential mechanism that forcibly generates a rotation difference between the left and right front wheels, and an automatic switching operation mechanism that automatically switches the front wheel forced differential mechanism to the forced differential state in conjunction with the turning operation of the steering wheel In the working traveling vehicle, the front wheel forced differential mechanism and the automatic switching operation mechanism are provided in a transmission case, and the automatic switching operation mechanism is interlocked with a steering mechanism in the transmission case. is there. That is, since the automatic switching operation mechanism for connecting the front wheel forced differential mechanism and the steering mechanism is incorporated in the transmission case, the automatic switching operation mechanism is exposed at the bottom of the body, as in the conventional automatic switching operation mechanism. The problem that the automatic switching operation mechanism is deformed or damaged due to grass entanglement or contact with obstacles can be resolved, and as a result, cleaning and greasing of the automatic switching operation mechanism are not required, improving maintainability. It is also possible to eliminate the inconvenience that the front-wheel forced differential mechanism cannot be switched based on the deformation or breakage of the automatic switching operation mechanism. Further, the automatic switching operation mechanism is characterized in that the automatic switching operation mechanism is interlocked and connected to a final transmission shaft of a steering reduction gear mechanism housed in a transmission case. That is, while the automatic switching operation mechanism is built in the transmission case, the front wheel forced differential mechanism is switched by the steering power in the final deceleration stage, so that it is possible to avoid inconvenience such as an increase in the steering wheel operation force. . Also, the automatic switching operation mechanism is characterized in that a shifter for switching the front wheel forced differential mechanism is interlocked to a steering range regulating plate provided on the final transmission shaft of the steering reduction gear mechanism via a connection link. It is. That is, since the front-wheel forced differential mechanism is switched using the existing steering range restriction plate, the number of components cannot be reduced, and an increase in the size of the transmission case can be avoided.

[0005]

Next, one embodiment of the present invention will be described with reference to the drawings. In the drawings, reference numeral 1 denotes a traveling body of a riding rice transplanter. The traveling body 1 is a transmission case 4 for inputting power via an continuously variable transmission mechanism 3 from an engine (not shown) mounted on the front of the body. A front axle case (not shown) for driving the front wheels 5 with power output from the transmission case 4;
The vehicle includes a rear axle case 7 for driving the rear wheel 6 with power output from the transmission case 4, an elevating link mechanism 9 to which a planting work machine 8 is mounted, and the like, and the front wheel 5 is steerable to a front axle case. And is linked to a pitman arm 10 described later via a drag link (not shown).

The transmission case 4 transmits the power of the input shaft 11 to the main clutch mechanism 12, the main clutch output shaft 12a, the first planted transmission shaft 13, the planted transmission mechanism 14, the second planted transmission shaft 15, and the torque. A planting power transmission path for transmitting power to the planting output shaft 19 via the limiter 16, the bevel gear mechanism 17, the planting clutch mechanism 18, and the like, and a power taken from the main clutch output shaft 12a are transmitted to a first traveling transmission shaft. 2
0, a rear wheel power transmission path for transmitting power to the rear wheel output shaft 24 via the traveling auxiliary transmission mechanism 21, the second traveling transmission shaft 22, the bevel gear mechanism 23, and the like, and the power taken out from the second traveling transmission shaft 22. To the left and right front wheel output shafts 2 via a differential mechanism 25.
A front wheel power transmission path transmitting to 6L and 26R is formed in the case.

The differential mechanism 25 includes a rotating case 2 having a ring gear (input gear) 25a integrally fixed on an outer peripheral surface thereof.
5b, a pinion shaft 25c radially supported by the rotating case 25b, a pair of pinion gears 25d rotatably supported by the pinion shaft 25c, and a pair of left and right side gears simultaneously meshed with the pair of pinion gears 25d, respectively. Output gear) 25e. If the rotational resistance (front wheel drive resistance) of the left and right side gears 25e is equal (when the aircraft is traveling straight), the pinion gear 25d
Rotates integrally with the ring gear 25a in a non-rotating state, and rotates the left and right side gears 25e at substantially constant speed. On the other hand, when a difference occurs in the rotational resistance of the left and right side gears 25e (when the vehicle turns, etc.), the pinion gear is rotated. 25d is the ring gear 25
The left and right side gears 2 rotate while rotating integrally with a.
During 5e, a rotation difference corresponding to the rotation resistance is generated in a passive manner.

A front wheel forced differential mechanism 27 is provided between the second traveling power transmission shaft 22 and one (right side in the present embodiment) front wheel output shaft 26R.
Reference numeral 7 denotes a transmission gear 2 which is rotatably supported on the right front wheel output shaft 26R at a predetermined interval and has a second traveling transmission shaft 22 side.
A pair of forced differential gears 3 always meshing with the gears 8 and 29, respectively.
0, 31 and the forced differential gears 30, 31 are spline-fitted to the right front wheel output shaft 26R.
And a switching clutch 32 having left and right meshing claws 32a which can be selectively meshed with the meshing claws 30a, 31a formed on the opposing surfaces of 0, 31, respectively. The reduction ratio of the gear 30 is
While the reduction ratio is set to be smaller than the reduction ratio of the ring gear 25a, the reduction ratio of the other forced differential gear 31 is set to be larger than the reduction ratio of the ring gear 25a. That is, the front wheel forced differential mechanism 27
The right front wheel output shaft 2 based on the selective engagement of the switching clutch 32 with the pair of forced differential gears 30 and 31.
When the right front wheel output shaft 26R is forcibly increased in speed, the left front wheel output shaft 26R is actuated based on the operation of the differential mechanism 25.
Since L is decelerated, the left and right front wheel output shafts 26L, 26R
In the meantime, while a constant rotation difference corresponding to the left turn can be forcibly generated, when the right front wheel output shaft 26R is forcibly decelerated, the left front wheel output shaft is generated based on the operation of the differential mechanism 25. Since the speed of 26L is increased, a constant rotation difference corresponding to right turning can be forcibly generated between left and right front wheel output shafts 26L and 26R.

Reference numeral 33 denotes a shift shaft provided inside the bottom of the transmission case 4, and the shift shaft 33 includes a convex portion 4 a formed on the bottom of the transmission case 4.
A shift fork 34 that is slidably supported in the left and right directions on the side wall 4b and that is fitted integrally with the groove 32b of the switching clutch 32 is integrally provided at one end thereof. That is, switching of the front wheel forced differential mechanism 27 is performed based on the sliding operation of the shift shaft 33, while the shifter shaft 33 is formed with a single detent groove 33 a corresponding to the neutral position of the switching clutch 32, The projection 4a of the transmission case 4 is provided with a detent ball 36 that fits into the detent groove 33a under the urging force of the detent ammunition 35.
The shift shaft 33 maintains the neutral position until an axial operation force exceeding the urging force of No. 5 is received.

Reference numeral 37 denotes a shifter provided on the bottom of the transmission case 4 so as to be rotatable left and right via a shifter rotating shaft 38. The shifter 37 is provided on the outer periphery of the shift shaft 33 so as to sandwich the tip of the shifter. A pair of collars 39 (flange portions) to be mounted, a pair of position holding rams 40 mounted on the outer peripheral portion of the collar 39, and the shift shaft 33 sandwiching the pair of position holding rams 40. It is linked to the shift shaft 33 via a pair of stopper rings 41 to be attached. When the shifter 37 is rotated in the left-right direction, one of the position-holding springs 40 presses and biases the shift shaft 33 to one side while being compressed. The shift shaft 33 slides to each of the left and right forced differential positions at the stage where the biasing force is exceeded, but after the shift shaft 33 is displaced to each of the forced differential positions,
The shift shaft 33 is held at each position by the stored force of the position holding bullet 39 that is stored in accordance with the shifter operation.

On the other hand, 42 is a transmission case 4
The steering reduction gear mechanism 42 includes a first gear 44 provided integrally with the input shaft 43 and a second gear 45 meshing with the first gear 44. An intermediate shaft 46 provided integrally, a third gear 46a formed on the outer peripheral surface of the intermediate shaft 46, an output shaft (final transmission shaft) 48 integrally provided with a sector gear 47 meshing with the third gear 46a, and the like. Have been. That is, the steering reduction gear mechanism 42 reduces the operation rotation of the steering wheel 51 input via the torque generator 49 and the steering shaft 50, and rotates the pitman arm 10 provided on the output shaft 48 left and right based on the reduced rotation. To move the steering wheel 5
1, the front wheel 4 is steered in response to the operation rotation of the steering shaft 1. The output shaft 48 has a stopper plate (steering range) that regulates the rotation range of the output shaft 48 based on contact with the intermediate shaft 46. (Regulation plate) 52 is provided,
The front wheel steering range (steering wheel operation range) is regulated within a predetermined range.

Reference numeral 53 denotes a connecting link provided inside the bottom of the transmission case 4.
Has a front end facing in the front-rear direction, a rear end facing in the left-right direction, and an intermediate portion inclined in plan view that connects both ends, and is formed in a substantially linear plate shape in side view. However, the front end thereof enters the notch 47a of the sector gear 47 and is swingably connected to the stopper plate 52 via the pin 53a, while the rear end is
It is swingably connected via a pin 53b to a long hole 54a of a shifter connecting arm 54 provided integrally with the shifter rotation shaft 38. That is, the steering wheel 5
An automatic switching operation mechanism 55 that pushes and pulls the shifter connecting arm 54 (shifter 37) in conjunction with the turning operation of 1 and automatically switches the front wheel forced differential mechanism 27 based on the pushing and pulling is configured. Since the automatic switching operation mechanism 55 is housed in the transmission case 4, it is not possible to reliably avoid entanglement of grass and contact with obstacles, and the operating oil injected into the transmission case 4 is not allowed. (Lubricating oil).
In the present embodiment, since the steering operation force is extracted from the output shaft (final reduction shaft) 48 of the steering reduction gear mechanism 42 and the front wheel forced differential mechanism 27 is switched, inconvenience such as an increase in the operation force of the steering wheel 51 is also avoided. You can do it.

In the structure described above, a front wheel forced differential mechanism 27 for forcibly generating a rotation difference between the left and right front wheels 5 is provided, and the front wheel forced differential mechanism 27 is
An automatic switching operation mechanism 55 for automatically switching to a forced differential state in conjunction with a turning operation of the steering wheel 51 is provided. The front wheel forced differential mechanism 27 and the automatic switching operation mechanism 55 are provided inside the transmission case 4. At the same time, the automatic switching operation mechanism 55 is linked to the steering reduction gear mechanism 42 in the transmission case 4, so that the automatic switching operation mechanism 55 is entangled with grass or deformed or damaged by contact with an obstacle. There is no inconvenience to do. Therefore, it is not possible to improve the maintainability by eliminating the need for cleaning and lubrication of the automatic switching operation mechanism 55, and the front-wheel forced differential mechanism 27 switches based on the deformation or damage of the automatic switching operation mechanism 55. The inconvenience of being disabled can be eliminated.

Further, since the automatic switching operation mechanism 55 is linked to the output shaft 48 of the steering reduction gear mechanism 42 provided in the transmission case 4, the front wheel forced differential mechanism 27 is operated by the steering operation force in the final deceleration stage.
As a result, it is possible to avoid inconvenience such as an increase in the operating force of the steering wheel 51 while the transmission case 4 is provided with the automatic switching operation mechanism 55.

The automatic switching operation mechanism 55 connects the shifter 37 for switching the front wheel forced differential mechanism 27 to an existing stopper plate 52 provided on the output shaft 48 of the steering reduction gear mechanism 42 via a connection link 53. Because of the interlocking connection, there is no need to add parts to the steering reduction gear mechanism 42. As a result, it is not possible to reduce the number of parts.
It is also possible to avoid an increase in size.

In connecting the connecting link 53 to the stopper plate 52, the front end of the connecting link 53 is inserted into the notch 47a of the sector gear 47, so that it is not necessary to secure a separate connecting space. In addition, the transmission case 4 can be downsized as compared with the case where the output shaft 48 is extended to secure the connection space.

[Brief description of the drawings]

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

FIG. 2 is a developed sectional view of a transmission case.

FIG. 3 is a sectional side view of the same.

FIG. 4 is a bottom sectional view of the same.

FIG. 5A is a bottom view of a main part showing a right turn state, and FIG.
FIG. 4 is a bottom view of a main part showing a left turning state.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Traveling body 4 Transmission case 5 Front wheel 27 Front wheel forced differential mechanism 37 Shifter 42 Steering reduction gear mechanism 48 Output shaft 52 Stopper plate 53 Connecting link 55 Automatic switching operation mechanism

Claims (3)

[Claims] 1. A steering mechanism for steering a front wheel in response to an operation of a steering wheel, a front wheel forced differential mechanism for forcibly generating a rotation difference between left and right front wheels, and a front wheel in conjunction with a turning operation of the steering wheel. An automatic switching operation mechanism for automatically switching the forced differential mechanism to a forced differential state, wherein the front wheel forced differential mechanism and the automatic switching operation mechanism are incorporated in a transmission case, and the automatic switching operation mechanism is provided. A working vehicle, wherein the vehicle is connected to a steering mechanism in a transmission case. 2. The traveling vehicle according to claim 1, wherein the automatic switching operation mechanism is interlocked with a final transmission shaft of a steering reduction gear mechanism provided in the transmission case. 3. The automatic switching operation mechanism according to claim 2, wherein the shifter for switching the front wheel forcible differential mechanism is interlocked with a steering range regulating plate provided on a final transmission shaft of the steering reduction gear mechanism via a connection link. A working traveling vehicle characterized by being connected.