JPH10129516A - Travelling drive device for farming machinery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a travelling drive device which runs and turns machinery smoothly. SOLUTION: This traveling drive device links a continuously variable transmission for travelling and a continuously variable transmission for operation 20 to an engine, links right and left internal gears 43R and 43L to the continuously variable transmission for travelling, links right and left differential shafts 46R and 46L to the continuously variable transmission for operation 20, so that they can be rotated with the same rotation number in reverse direction each other, links right and left sun gears 49R and 49L to right and left differential shafts 46R and 46L, engages right and left planetary gears 40R, 40L, 41R, and 41L to right and left internal gears 43R and 43L and right and left sun gears 49R and 49L, and right and left planetary gears 40R, 40L, 41R, and 41L are journalled to right and left cages 42R and 42L which are fixed into drive shafts of right and left travelling units, and rotate and increase and decrease the speed of machinery by increasing and decreasing the rotation number of right and left drive shafts 36R and 36L in accordance with the rotation number of both continuously variable transmissions. In this case, a clutch is placed between right and left differential shafts 46R and 46L and the device is constituted to switch right and left differential shafts 46R and 46L to off state and on state by the operation of the clutch.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a traveling drive device for an agricultural work machine.

[0002]

2. Description of the Related Art Conventionally, in an agricultural work machine, the left and right traveling parts are driven by a hydrostatic continuously variable transmission, and the traveling speed of the left and right traveling parts is made different so that the machine body turns. There is.

[0003]

However, in the above-mentioned conventional agricultural working machine, the straightness is not improved due to individual differences between the left and right continuously variable transmissions, irregularities in the left and right operation mechanisms for operating the left and right continuously variable transmissions, and play. In addition, since the right and left continuously variable transmissions are controlled without mutual relation, there is a problem that turning is performed rapidly and the field scene is damaged.

Further, when the continuously variable transmission is a hydrostatic continuously variable transmission, the hydrostatic continuously variable transmission has a low power transmission efficiency in a high rotation range, so that the desired traveling speed range is limited. This required a high-powered engine to cover, consuming more fuel and being uneconomical.

[0005]

SUMMARY OF THE INVENTION Accordingly, the present invention provides an engine in which a continuously variable transmission for traveling and a continuously variable transmission for steering are interlocked and connected to the engine, and the left and right internal gears are interlocked and connected to the continuously variable transmission for driving. In addition, the left and right differential shafts are interlockingly connected to the steering continuously variable transmission so as to rotate at the same rotational speed in opposite directions to each other, and the left and right sun gears are interlockingly connected to the left and right differential shafts. The left and right planetary gears mesh with the internal gear and the left and right sun gears, and the left and right planetary gears are supported on left and right cages fitted to the drive shafts of the left and right traveling parts, and are driven left and right according to the rotation speed of both continuously variable transmissions. A traveling drive device for increasing / decreasing the rotation speed of a shaft to increase / decrease the rotation of a vehicle body. A clutch body is interposed between the left and right differential shafts, and the left and right differential shafts are disconnected by operating the clutch body. It is configured to be switchable between the state and the connection state.

Further, a brake body is attached to at least one of the left and right differential shafts, and the left and right differential shafts can be switched between a stopped state and a rotating state by operating the brake body.

Further, the brake body is configured to be able to change the operating pressure in inverse proportion to the running speed of the body.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A traveling drive system according to the present invention comprises a hydrostatic traveling continuously variable transmission and a steering continuously variable transmission comprising an engine equipped with a variable displacement hydraulic pump and a constant displacement hydraulic motor. In this system, the drive shafts of the left and right drive wheels are connected to both transmissions via a left and right planetary gear mechanism.

The left and right planetary gear mechanism includes a left and right internal gear operatively connected to a traveling continuously variable transmission, a left and right sun gear operatively connected to a steering continuously variable transmission via a gear mechanism, a left and right internal gear, and a left and right internal gear. A left and right planetary gear meshing with the sun gear is provided, and the left and right planetary gears are supported by left and right cages fitted to the drive shafts of the left and right traveling units.

The gear mechanism is configured to function so that left and right differential shafts interlockingly connected to the left and right sun gears rotate in opposite directions at the same rotational speed.

The rotational speeds of the left and right drive shafts are respectively increased or decreased in accordance with the rotational speeds of the two continuously variable transmissions to increase or decrease the turning of the body.

In addition, a hydraulic clutch is provided between the left and right differential shafts, and the left and right differential shafts can be switched between a disconnected state and a connected state by operating the hydraulic clutch.

In addition, a potentiometer is attached to a turning column of the steering wheel, and the neutral position of the steering wheel is detected by the potentiometer. When the steering wheel is in the neutral position, the hydraulic brake is locked and the steering wheel is neutralized When it is not at the position, the hydraulic brake is released.

When the steering wheel is steered, the hydraulic brake is released and the differential shaft is rotatable. The power of the engine is transmitted to the left and right drive shafts via the steeringless transmission. Transmission in the reverse rotation direction, increasing the speed of one drive shaft, decelerating the other drive shaft,
This makes it possible to cause a difference in traveling speed between the left and right traveling sections, and to turn the aircraft body right and left.

On the other hand, if the steering wheel is not steered, the hydraulic brake is not released and the differential shaft cannot rotate, and accordingly the power of the engine is applied to the left and right drive shafts only through the continuously variable transmission for traveling. The transmission is performed, and no difference in traveling speed occurs between the left and right traveling portions, so that the body can be made to travel straight.

A proportional control valve capable of proportionally controlling the cross-sectional area of the internal oil passage is provided in the middle of the oil passage of the hydraulic brake so that the operating pressure of the hydraulic brake can be changed in inverse proportion to the running speed of the machine. It was made.

Therefore, when the vehicle is running at high speed, the operating pressure of the hydraulic brake is low, and even if the steering wheel is steered, if the steering rotation angle is small, the hydraulic brake is not immediately released. Therefore, the left and right differential shafts cannot rotate, and the aircraft continuously travels straight, which can maintain the straightness of the aircraft satisfactorily and improve the operational feeling during high-speed traveling. .

On the other hand, when the vehicle is running at a low speed, the operating pressure of the hydraulic brake is increased, and the hydraulic brake is released according to the steering operation of the steering wheel, so that the aircraft can be turned.

Further, in the traveling drive device according to the present invention, a hydraulic brake is mounted on at least one of the left and right differential shafts, and the left and right differential shafts can be switched between a stopped state and a rotating state by operating the hydraulic brake. It is composed.

Then, the hydraulic clutch is disengaged and the left and right differential shafts are rotated at the same speed in opposite directions, respectively, so that the power of the engine is transmitted via the continuously variable transmission for traveling and the continuously variable transmission for steering. The driving force is transmitted to the left and right driving shafts, one of the driving shafts is accelerated, and the other driving shaft is decelerated, so that a difference in traveling speed occurs between the left and right traveling portions, so that the body can be turned left and right.

Further, by connecting the hydraulic clutch and directly connecting the left and right differential shafts, the left and right differential shafts cannot be rotated, and the power of the engine is transmitted to the left and right drive shafts only through the continuous transmission for traveling. The drive shafts rotate in the same direction at the same speed, so that there is no difference in running speed between the left and right running parts, and therefore, it is possible to reliably maintain the state in which the aircraft is traveling straight, and to improve the straightness of the aircraft. It can be secured well.

[0022]

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

FIG. 1 is a left side view of a tractor TR as a farm work machine having the traveling drive device DR according to the present invention,
The tractor TR has crawler-type left and right traveling portions 1L and 1R attached to the left and right sides of the body frame 2, and the motor unit 3 is mounted on the front upper surface of the body frame 2 and the body frame 2
The cabin 4 is placed at the rear of the upper surface of the vehicle, and an operating unit 5 is formed in the cabin 4.

The driving unit 5 has a steering wheel 6
The seat 7 is disposed behind the seat 7 at a predetermined interval, and a forward / reverse speed change lever 8 is erected on the right side of the seat 7 so as to be tiltable forward and backward. In the figure, 9 is a running frame, 10 is a crawler track, 11L (11R) is a driving wheel, 12 is an idle wheel, 13
Is a lower wheel, 14 is an upper wheel, 15 is a lower link, and 16 is a work machine elevating mechanism.

As shown in FIGS. 2 and 3, the traveling drive device DR is arranged in the order of the engine 17, the front transmission 18, and the rear transmission 19 of the motor unit 3 from the front of the fuselage. Is mounted with a hydrostatic steering continuously variable transmission 20 (see FIG. 9) composed of a variable displacement hydraulic pump 76 and a constant displacement hydraulic motor 78. On the other hand, a variable A hydrostatic continuously variable transmission 21 composed of a displacement hydraulic pump and a constant displacement hydraulic motor is mounted.

Next, a specific configuration of the traveling drive device DR will be described in the order of power transmission.

As shown in FIGS. 2 to 6, a front transmission input shaft 23 operatively connected to the engine 17 via a double hook joint 22 is connected to the input of the continuously variable steering transmission 20 via a gear train 25. Linked to shaft 20a, the same input shaft
20a rear end, front mission 18 and rear mission
19 and the universal joints 26, 26
Via the interlocking shaft 27, the input shaft 21 of the traveling continuously variable transmission 21
a of the input shaft 21a.
A power take-out clutch 31 provided in the rear transmission 19, a power take-out transmission portion 30 capable of neutral and two-stage speed change, and a meshing reduction gear 30a are operatively connected to a power take-out shaft 31.
In the figure, 52 is a brake.

On the other hand, the output shaft 21b of the traveling continuously variable transmission 21
Is linked to a rear transmission output shaft 34 via a traveling clutch 32 and a subtransmission portion 33 capable of neutral and three-speed shifting. The front end of the rear transmission output shaft 34 is connected to universal joints 26 and 26 and the second Via an interlocking shaft 35, it is interlockingly connected to the rear end of a front input shaft 36 pivotally supported on the rear surface of the front transmission 18, and is driven left and right via a running mesh bevel gear 37 formed at the front end of the front input shaft 36. Intermediate shaft supported between shafts 38L and 38R
Linked to 39.

As shown in FIG. 5, the intermediate shaft 39 is attached to the left and right driving shafts 38L, 38R of the left and right traveling parts 1L, 1R by the left and right planetary gear mechanisms 40L, 40L.
The left and right drive wheels 11L and 11R are linked to the drive shafts 38L and 38R, respectively.

The left and right planetary gear mechanisms 40L and 40R have left and right internal gears 43L and 43R fitted on both left and right ends of the intermediate shaft 39, respectively.
Left and right cages 42L and 42R are attached to left and right planetary gears 41L and 41R on 43L and 43R.
The left and right cages 42L, 42R are fitted to the left and right drive shafts 38L, 38R. In the drawing, 51L and 51R are the rotation axes of the left and right planetary gears 41L and 41R.

On the other hand, as shown in FIG. 5, the steering continuously variable transmission 20 has a left and right differential shaft 46L, 46R interlockingly connected via a gear mechanism 48 to an output shaft 20b interlocking with the input shaft 20a. And
The gear mechanism 48 includes a steering bevel gear at the front end of the output shaft 20b.
45, and the left and right differential shafts 46L,
Right and left steering passive bevel gears 47L, 47R fitted to the inner end of 46R
Are engaged.

As shown in FIG. 5, the left and right differential shafts 46L and 46R are also linked to the left and right drive shafts 38L and 38R of the left and right traveling units 1L and 1R via left and right planetary gear mechanisms 40L and 40R. That is, the left and right steering gears are attached to the outer ends of the left and right differential shafts 46L and 46R.
The left and right sun gears 49L, 49R are meshed with the left and right steering gears 50L, 50R, and the left and right sun gears 49L, 49R are meshed with the left and right planetary gear mechanisms 40L, 40R. ,
38R and the right and left planetary gears 41L and 41R.
Is engaged.

In the middle of the right differential shaft 46R, a multi-plate type hydraulic brake as a brake body 60 which operates in accordance with the steering operation of the steering wheel 6 is mounted.
The left and right differential shafts 46L and 46R can be switched between a stopped state and a rotating state by the differential between the left and right differential shafts 46R and 46R. The piston 62 is urged against the multi-plate 63 by a spring 61. In the figure, reference numeral 64 denotes an oil passage for operating the brake body 60.

Further, a potentiometer is attached to a rotating support of the steering wheel 6, and the neutral position of the steering wheel 6 is detected by the potentiometer. When the steering wheel 6 is in the neutral position, the brake body 60 is locked. When the steering wheel 6 is not in the neutral position, the brake body 60 is released.

When the steering wheel 6 is steered, the brake body 60 is released, the right differential shaft 46R is rotatable, and the power of the output shaft 20b of the steering transmission 20 is changed between left and right. The driving force is transmitted to the differential shafts 46L and 46R via the steering driving bevel gear 45 in mutually opposite rotational directions.

Accordingly, when the brake body 60 is released, the power of the engine 17 is transmitted to the continuously variable transmission 21 for steering and the continuously variable transmission 20 for steering, and transmitted to the continuously variable transmission 21 for traveling. The output power is output shaft 21b → sub transmission unit 33 → rear transmission output shaft 34 → second interlocking shaft 35 → front input shaft 36 → running mesh bevel gear 37 → intermediate shaft 39 → left and right internal gears 43L, 43R → left and right Planet gears 41L, 41R → Left and right cages 42L, 42R → Left and right drive shafts 38L, 38
R, on the other hand, the power transmitted to the continuously variable steering transmission 20 is output from the output shaft 20b → the driving bevel gear 45 → the left and right steering passive bevel gears 47L, 47R → the left and right differential shaft. 46L, 46R → left and right steering meshing gear 50L, 50R → left and right sun gear 49L, 49R → left and right planetary gear 41L, 41R → left and right cage 42L, 42R → left and right drive shaft 38L, 38
Communicated to R.

In addition, the power transmitted to the continuously variable steering transmission 20 is transmitted in the direction in which the left and right drive shafts 38L, 38R are rotated in reverse directions, so that the speed of one of the drive shafts 38L (38R) is increased. The other drive shaft 38R (38L) is decelerated.

Therefore, a difference in running speed occurs between the left and right running portions 1L and 1R, and the body can be turned left and right.

On the other hand, if the steering wheel 6 is not steered, the brake body 60 is not released, the right differential shaft 46R cannot rotate, and the output shaft 20 of the steering continuously variable transmission 20 is accordingly moved.
b cannot rotate, so that the left and right differential shafts 46L, 46R maintain the stopped state.

Therefore, in the state where the brake body 60 is not released, the power of the engine 17 is transmitted to the continuously variable transmission 21 for traveling and the continuously variable transmission 20 for steering. Is transmitted to the left and right drive shafts 38L, 38R, and only the power transmitted to the continuously variable transmission 21 is transmitted to the left and right drive shafts 38L, 38R.

Therefore, the left and right drive shafts 38L, 38R are not accelerated or decelerated by the power transmitted to the steering continuously variable transmission 20, so that no difference in traveling speed occurs between the left and right traveling portions 1L, 1R. The straightness of the aircraft can be maintained well.

In the middle of the oil passage 64 of the brake body 60,
A proportional control valve 73 capable of proportionally controlling the cross-sectional area of the internal oil passage is provided, and the operation pressure of the brake body 60 can be changed in inverse proportion to the running speed of the body.

That is, an operation angle detection sensor 77 is attached to the base end of the forward / reverse speed change lever 8, and the operation angle detection sensor 77
Is output to the control unit 72, and the control unit 72 controls the proportional control valve 73 in accordance with the tilt angle of the forward / reverse shift lever 8, and when the tilt angle of the forward / reverse shift lever 8 is large, When the traveling speed is high, the operation pressure of the brake body 60 is reduced.

Therefore, when the vehicle is running at high speed, the operating pressure of the brake body 60 is low, and even if the steering wheel 6 is steered, if the steering rotation angle is small, the brake body 60 is immediately released. And the left and right differential shaft 46L,
The 46R could not rotate, and the aircraft continued to travel straight, maintaining the straightness of the aircraft well and improving the operational sensation during high-speed traveling.

On the other hand, when the vehicle is running at low speed, the brake
The operation pressure of the steering wheel 6 increases, and the brake body 60 is released according to the steering operation of the steering wheel 6, so that the aircraft can be turned.

As shown in FIG. 9, the continuously variable steering transmission 20 has a forward / reverse switching valve 75 in the middle of a closed oil passage 79 for interlocking the variable displacement pump 76 and the constant displacement hydraulic motor 78. A forward / reverse switching valve 75 is interposed with the block valve 74.
Is configured such that the constant displacement hydraulic motor 78 can be switched between forward rotation, stoppage, and reverse rotation in accordance with the steering operation of the steering wheel 6.
According to the steering operation, the closed oil passage 79 is connected and can be switched to a cutoff state.

When the steering wheel 6 is steered, that is, when the body is turned, the forward / reverse switching valve 75 switches to a position for rotating the constant displacement hydraulic motor 78 forward or backward, and the block valve 74. Is switched to a position communicating with the closed oil passage 79, so that the constant displacement hydraulic motor 78 is operated in accordance with the steering operation of the steering wheel 6, and the body can be turned.

On the other hand, when the vehicle is driven straight without steering operation of the steering wheel 6, a forward / reverse switching valve is provided.
75 is switched to a position for stopping the constant displacement hydraulic motor 78, and the block valve 74 is switched to a position for shutting off the closed oil passage 79, so that the constant displacement hydraulic motor 78 can be stopped, and the aircraft moves straight. be able to.

Therefore, even if there is an individual difference in the neutral state of the constant displacement hydraulic motor 78, the operation of the two valves 74 and 75
The constant displacement hydraulic motor 78 can be stopped reliably,
The straightness of the aircraft can be maintained well.

FIG. 7 shows another embodiment of the traveling drive device DR according to the present invention, in which a clutch body 65 that operates between the left and right differential shafts 46L, 46R in accordance with the steering operation of the steering wheel 6 is provided. The left and right differential shafts 46L, 46R can be switched between a stopped state and a rotated state by the operation of the clutch body 65.

The clutch body 65 has a cylindrical clutch projection 46a projecting from the base end of the left differential shaft 46L.
A plurality of multi-plates 68 are spline-fitted into spline grooves formed on the outer peripheral side of the clutch body, while a cylindrical clutch body 66 is fitted on the base end of the right differential shaft 46R, and the inner peripheral side face of the clutch body 66 is fitted on the inner peripheral side. A plurality of multi-plates 67 are spline-fitted to the formed spline grooves in a state where the multi-plates 67 face the multi-plate 68, and a piston 69 is urged to the multi-plate 67 by a spring 70.
Piston in the oil passage 71 formed in the center of the section
The multiple plates 67 and 68 can be disengaged by moving the 69 against the urging force of the spring 70.

When the steering wheel 6 is steered, the clutch body 65 is disengaged, and the left and right differential shafts 46L and 46R can be rotated.
The power of the output shaft 20b of the motor 20 is transmitted to the left and right differential shafts 46L, 46R via the steering bevel gear 45 in mutually opposite rotational directions.

Accordingly, when the clutch body 65 is disengaged, the power of the engine 17 is supplied to the continuously variable transmission 21 for traveling and the continuously variable transmission for steering in the same manner as when the brake body 60 is released. 20 and the left and right drive shafts 38L, 38
Communicated to R.

In addition, the power transmitted to the continuously variable steering transmission 20 is transmitted in the direction in which the left and right drive shafts 38L, 38R are respectively rotated in reverse, so that one of the drive shafts 38L (38R) is accelerated. The other drive shaft 38R (38L) is decelerated.

As a result, a difference in running speed occurs between the left and right running sections 1L and 1R, and the body can be turned left and right.

On the other hand, when the steering wheel 6 is not steered, the clutch body 65 is connected and the left and right differential shafts 46L, 46L are connected.
R cannot rotate, and accordingly the output shaft 20b of the continuously variable steering transmission 20 also cannot rotate, so that the left and right differential shafts 46L, 46
R remains stopped.

Accordingly, when the clutch body 65 is connected, the power of the engine 17 is transmitted to the continuously variable transmission 21 for traveling and the continuously variable transmission 20 for steering.
The power transmitted to the left and right drive shafts 38L, 38R is not transmitted,
Only the power transmitted to the continuously variable transmission 21 is driven by the left and right drive shafts.
It is transmitted to 38L and 38R.

Therefore, the left and right drive shafts 38L, 38R are not accelerated or decelerated by the power transmitted to the steering continuously variable transmission 20, so that no difference in traveling speed occurs between the left and right traveling portions 1L, 1R. The straightness of the aircraft can be maintained well.

Further, the left and right differential shafts 46 are provided by the clutch body 65.
Since the steering wheels 6 and L are directly connected, when the steering wheel 6 is returned to the neutral position, the left and right differential shafts 46L and 46R are not immediately connected but are continuously connected by the clutch body 65. Since the traveling speed of the body changes continuously, the steering operation feeling during traveling can be improved.

[0060]

The present invention is embodied in the form described above and has the following effects.

(1) According to the present invention, a clutch is interposed between the left and right differential shafts, and the left and right differential shafts can be switched between a disconnected state and a connected state by the operation of the clutch body. By rotating the left and right differential shafts in the opposite direction at the same rotational speed with the clutch body disengaged,
The power of the engine is transmitted to the left and right drive shafts via the continuously variable transmission for traveling and the continuously variable transmission for steering, one of the drive shafts is increased in speed, the other is reduced in speed, and the traveling speed is transmitted to the left and right traveling portions. A difference occurs, and the aircraft can be turned left and right.

Further, by connecting the clutch body and directly connecting the left and right differential shafts, the left and right differential shafts cannot rotate.
The power of the engine is transmitted to the left and right drive shafts only through the continuously variable transmission for traveling, and the left and right drive shafts rotate in the same direction at the same speed. It is possible to reliably maintain the state in which the body is straightly moved, and it is possible to properly maintain the straightness of the body.

Further, since the left and right differential shafts are directly connected by the clutch body, when the steering wheel is returned to the neutral position, the left and right differential shafts are not connected immediately,
The vehicle body is continuously connected by the clutch body, so that the traveling speed of the aircraft body changes continuously, and the steering operation feeling during traveling can be improved.

(2) According to the second aspect of the present invention, a brake body is attached to at least one of the left and right differential shafts, and the left and right differential shafts can be switched between a stopped state and a rotating state by operating the brake body. With this configuration, the brake body is released and the left and right differential shafts are rotated in opposite directions, so that the power of the engine is transmitted through the continuously variable transmission for traveling and the continuously variable transmission for steering. The speed of one of the drive shafts is increased, and the speed of the other drive shaft is reduced, so that a difference in running speed occurs between the left and right running portions, so that the aircraft can be turned left and right.

Further, by holding the left and right differential shafts in a stopped state by the brake body, the power of the engine is transmitted to the left and right drive shafts via only the traveling continuously variable transmission, and the left and right drive shafts are driven in the same direction at the same speed. As a result, there is no difference in traveling speed between the left and right traveling portions, and therefore, the state in which the body is straightened can be reliably maintained, and the straightness of the body can be reliably ensured.

(3) According to the third aspect of the present invention, since the operating load of the brake body is configured to be changeable in inverse proportion to the traveling speed of the body, the operation of the brake body is performed during high-speed traveling. If the load becomes low and the steering wheel is steered and the steering rotation angle is small, the brake body will not be released immediately, the left and right differential shafts will not rotate, and the aircraft will continue Then, the straightness of the aircraft can be maintained satisfactorily, and the operational feeling during high-speed running can be improved.

When the vehicle is running at a low speed, the operating load of the brake body is increased, and the brake body is released according to the steering operation of the steering wheel, so that the body can be turned smoothly and quickly.

[Brief description of the drawings]

FIG. 1 is a left side view of an agricultural work machine provided with a traveling drive device according to the present invention.

FIG. 2 is an explanatory plan view schematically showing the configuration of a traveling drive device.

FIG. 3 is a plan view showing a configuration of a traveling drive device.

FIG. 4 is a partially cutaway side view of the front transmission.

FIG. 5 is a partially sectional explanatory view showing the internal configuration of a front transmission.

FIG. 6 is a partially cutaway side view of the rear transmission.

FIG. 7 is a partially sectional plan view showing a clutch body.

FIG. 8 is an explanatory view showing a control unit of the brake body.

FIG. 9 is an explanatory view schematically showing an internal configuration of a continuously variable steering transmission.

[Explanation of symbols]

 DR Travel drive device TR Tractor 1L, 1R Travel unit 20 Steering gearless transmission 21 Travelless gearless transmission 37 Meshing bevel gear 38L, 38R Drive shaft 39 Intermediate shaft 40L, 40R Planetary gear mechanism 41L, 41R Planetary gear mechanism 42L, 42R Cage 43L, 43R Internal gear 45 Steering bevel gear 46L, 46R Differential shaft 47L, 47R Steering passive bevel gear 48 Gear mechanism 49L, 49R Sun gear 50L, 50R Steering mesh gear 60 Brake body 65 Clutch body 73 Proportional control valve

Claims (3)

[Claims] A continuously variable transmission for traveling (21) and a continuously variable transmission for steering (20) are interlocked to an engine (17), and a left and right internal gear (43L) is connected to the continuously variable transmission for traveling (21). , 43R) and the continuously variable transmission for steering (20) so that the left and right differential shafts (46L, 46R) rotate in opposite directions at the same rotational speed. The left and right sun gears (49L, 49R) are interlockingly connected to the driving shaft (46L, 46R), and the left and right internal gears (43L, 43R) and the left and right sun gears (4
9L, 49R) and the left and right planetary gears (41L, 41R) mesh with the drive shaft (38) of the left and right traveling parts (1L, 1R).
L, 38R) and the left and right cages (42L, 42R) fitted to the left and right drive shafts (38, 38) according to the rotation speed of both continuously variable transmissions (20, 21).
(L, 38R) to increase or decrease the rotation speed of the vehicle, respectively, to increase / decrease the turning speed of the vehicle, comprising a clutch body (65) interposed between the left and right differential shafts (46L, 46R). The left and right differential shaft (46L, 46
R) is configured to be switchable between a disconnected state and a connected state. 2. A continuously variable transmission for traveling (21) and a continuously variable transmission for steering (20) are interlockedly connected to an engine (17), and a left and right internal gear (43L) is connected to the continuously variable transmission for traveling (21). , 43R) and the continuously variable transmission for steering (20) so that the left and right differential shafts (46L, 46R) rotate in opposite directions at the same rotational speed. The left and right sun gears (49L, 49R) are interlockingly connected to the driving shaft (46L, 46R), and the left and right internal gears (43L, 43R) and the left and right sun gears (4
9L, 49R) and the left and right planetary gears (41L, 41R) mesh with the drive shaft (38) of the left and right traveling parts (1L, 1R).
L, 38R) and the left and right cages (42L, 42R) fitted to the left and right drive shafts (38, 38) according to the rotation speed of both continuously variable transmissions (20, 21).
(L, 38R) to increase or decrease the number of rotations, respectively, to increase or decrease the turning of the aircraft body, a traveling drive device, at least one of the left and right differential shafts (46L, 46R) attached to the brake body (60), A traveling drive device for an agricultural work machine, wherein the left and right differential shafts (46L, 46R) can be switched between a stopped state and a rotating state by operation of the brake body (60). 3. The travel drive device for an agricultural work machine according to claim 2, wherein the brake body (60) is configured to be capable of changing an operation load in inverse proportion to a travel speed of the machine body.