JP3499068B2 - Travel drive for agricultural tractors - Google Patents

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 tractor.

[0002]

2. Description of the Related Art Conventionally, in an agricultural tractor, the left and right traveling parts are driven by a hydrostatic continuously variable transmission, and
There is one in which the driving speed to the left and right traveling parts is made different so that the aircraft makes a turn.

[0003]

However, due to individual differences between the left and right continuously variable transmissions, the inconsistency of the left and right operation mechanisms for operating the left and right continuously variable transmissions, and rattling, the straightness is poor, and the left and right continuously variable transmissions are different. Since the machines are controlled independently of each other, there is also a problem that the field scene is damaged due to rapid turning.

Further, when the above-mentioned continuously variable transmission is a hydrostatic type continuously variable transmission, since the hydrostatic type continuously variable transmission has low power transmission efficiency in a high rotation range, it covers a desired traveling speed range. In order to do so, a high output engine is required, and there is a problem that it is uneconomical because fuel consumption increases.

[0005]

Therefore, in the present invention, a continuously variable transmission for traveling is interlockedly connected to an engine, and each drive shaft of left and right traveling portions is interlockedly connected to the continuously variable transmission for travelingly. The drive shafts are driven in the same rotation direction by the traveling continuously variable transmission, while the steering continuously variable transmission is linked to the engine, and the steering continuously variable transmissions are connected to the drive shafts of the left and right traveling parts. The drive shafts can be driven in opposite directions by the steering continuously variable transmission, and the speed of each drive shaft can be increased or decreased by both continuously variable transmissions to accelerate or decelerate the aircraft. An agricultural tractor having a steering wheel linked to a steering continuously variable transmission and a forward / reverse gearshift lever linked to a traveling continuously variable transmission. A drive unit for driving an agricultural tractor having the following features. Is to St. provide a driving device.

[0006] The output shaft of the continuously variable transmission for traveling is interlockingly connected to the auxiliary transmission unit, and the auxiliary transmission unit is interlockingly connected to the left and right outer gears of the left and right planetary gear mechanisms, and the output shaft of the continuously variable transmission for steering is The left and right planetary gears of the left and right planetary gear mechanisms are interlocked and linked to the left and right running parts via gear mechanisms that transmit the rotation directions to each other in opposite directions.

The gear mechanism is provided with a lock mechanism for rotating left and right rotations in the same direction.

Further, it also has the following features.

Each of the continuously variable transmissions is of a hydrostatic type and is composed of a variable displacement hydraulic pump and a constant displacement hydraulic motor.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a side view of an agricultural tractor TR equipped with a traveling drive device DR according to the present invention. The agricultural tractor TR is a machine frame 2 equipped with crawler type left and right traveling parts 1L, 1R. A prime mover section 3 is mounted on the front part of the upper surface, a cabin 4 is mounted on the rear side of the prime mover section 3, and an operating section 5 is arranged in the cabin 4.

The driving unit 5 has a steering wheel 6 at the front.
Is arranged so as to be steerable and rotatable, a seat 7 is arranged behind the seat 7 at a predetermined interval, and a forward / reverse shift 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 belt, 11 is a drive 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 working machine lifting mechanism.

2 and 3 show the arrangement of the traveling drive device DR. The engine 17, the front mission 18, and the rear mission 19 mounted on the prime mover section 3 are arranged in this order from the front along the longitudinal centerline of the machine body. And then Front Mission 18
On the rear surface, a hydrostatic steering continuously variable transmission 20 composed of a variable displacement hydraulic pump and a constant displacement hydraulic motor was attached.
At the front of the rear mission 19, a hydrostatic traveling continuously variable transmission 21 composed of a variable displacement hydraulic pump and a constant displacement hydraulic motor is attached, and the traveling drive unit DR is arranged in the order of power transmission.
Each part of will be described.

FIGS. 4 and 5 show a front mission 18, and FIG. 6 shows a rear mission 19. A front mission input shaft 23, which is interlocked with an engine 17 via a double hook joint 22, is connected via a gear train 25. The steering continuously variable transmission 20 is interlockingly connected to the input shaft 20a, and the input shaft 20a
At the rear end, front mission 18 and rear mission 19
Input shaft 21a of the continuously variable transmission 21 for traveling via universal joints 26, 26 and a first interlocking shaft 27 provided between
The rear end of the input shaft 21a is connected to the power take-off clutch 29 provided in the rear mission 19, the power take-out shift unit 30 capable of neutral and two-stage shifting, and the meshing reduction gear.
It is interlockingly connected to the power take-off shaft 31 via 30a.

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

The left and right drive shafts 38L and 38R are intermediate shafts.
Via left and right planetary gear mechanisms 40L and 40R left and right planetary gears 41L and 41R and left and right cages 42L and 42R, which are arranged on the left and right sides of 39, are linked to the left and right drive wheels 11L and 11R of the left and right traveling parts 1L and 1R, respectively. The left and right outer gears 43L and 43R of the left and right planetary gear mechanisms 40L and 40R are fitted to the left and right ends of the intermediate shaft 39.

On the other hand, a steering driving bevel gear 45 is formed at the front end of the output shaft 20b of the steering continuously variable transmission 20, and the steering driving bevel gear 45 is formed inside the left and right steering shafts 46L, 46R. The left and right steering passive bevel gears 47L and 47R fitted to the ends mesh with each other to form the gear mechanism 48.The outer ends of the left and right steering shafts 46L and 46R and the left and right sun gears 49L of the left and right planetary gear mechanisms 40L and 40R are formed. , 49R and interlocking gears 50L, 50R for left and right steering, respectively, and splines 51L, 51R formed on the inner ends of the left and right steering shafts 46L, 46R.
Three parts 51a that can be fitted to R and the splines 51L and 51R
A lock mechanism 51 is provided to prevent rotation of the left and right steering shafts 46L and 46R. In FIG. 6, 52 is a brake.

Next, referring to FIGS. 7 to 11, the steering device ST
Will be described.

As shown in FIGS. 7 and 8, the steering apparatus ST is a steering system in which a stay 54 is projectingly provided on the front inner surface of the cabin 4 and fixed to the rear end of the stay 54 in an inclined state of front low rear high. A steering shaft 56 having a steering wheel 6 attached to the upper end is rotatably inserted into the post 55, and the lower end of the steering shaft 56 is attached to the universal joints 26, 26 and an extension shaft 57.
And an operation input shaft 59 projecting from the upper surface of a steering box 58 attached to the lower surface of the floor of the cabin 4 through interlocking.

A steering acceleration / deceleration mechanism SA is provided inside the steering box 58 to make the rotational speed of the steering continuously variable transmission 20 proportional to the operation amount of the steering wheel 6.

As shown in FIGS. 9 to 11, the steering acceleration / deceleration mechanism SA includes a rack support shaft in the steering box 58.
60 is installed in the left-right direction and the rack is supported on the front of the rack support shaft 60.
The rack support 61a to which the 61 is attached is slidably fitted to the left and right, the pinion 62 formed at the lower end of the operation input shaft 59 is meshed with the rack 61, and a cross section is formed on the lower surface of the rack support 61a. A central portion of a tilting body 63 having a substantially U-shaped lower opening is pivotally mounted so as to be rotatable left and right, and a steering box is provided.
An operating pin 66 protruding from the tip of an internal operating lever 65 connected to the inner end of an operating shaft 64 that passes through the bottom wall of 58 is inserted into the opening of the tilting body 63 via a ball bearing 67,
An external actuating lever 68 is connected to the outer end of the actuating shaft 64, and the external actuating lever 68 is operated by a connecting rod 69 and a steering variable speed lever 70a to change the steering continuously variable transmission 20 for steering. It is linked to the shaft 70.

Further, a screw rod 71 extending in the left-right direction is installed in the steering box 58, and a return seat biasing member 72 is attached to the screw rod 71.
The coil spring 74 is housed in the cylinder body 73 fixed to the rack 61, and both ends of the coil spring 74 are fitted with washers 75, 75 and retaining rings 76, 7 respectively.
6 With the adjustment nuts 77, 77 screwed to the outside of the washer 75, 75 of the screw rod 71, the seat urging body 72 is slidable inward but not slidable outward. I support you.

Further, a forward / reverse switching mechanism SB is provided in the steering box 58 to reverse the rotational direction of the output of the steering continuously variable transmission 20 in association with the forward / backward tilt of the forward / reverse transmission lever 8 which will be described later. Thus, the machine body is turned in the turning direction of the steering wheel 6 regardless of whether the vehicle is moving forward or backward.

In the forward / reverse switching mechanism SB, a tilting shaft 78 extending in the left-right direction is rotatably installed, and a sliding body 80 is slidably fitted on the tilting shaft 78 via a ball spline 79. A connecting rod 81 for connecting the downwardly extending portion 80a of the sliding body 80 and the tilting body 63.
The tilting lever 78 is connected to the projecting end of the tilting shaft 78, and a fixed end of the tilting lever 82 is connected to the working end of a tilting hydraulic cylinder 83 pivotally attached to the machine body frame 2. A return mechanism 84 for returning the tilting shaft 78 to the neutral position is interlockingly connected.

Further, as shown in FIGS. 7 and 8, the forward / reverse speed change is performed through a support shaft 86 which is inserted through an upper end portion of a forward / reverse speed change lever support member 85 standing upright on the right side of the seat 7 of the machine body frame 2. The lever 8 is pivotally supported so that it can be tilted back and forth, and a substantially reverse T-shaped forward / reverse transmission plate 87 is continuously provided on the support shaft 86. The rear end of the forward / reverse transmission plate 87 is connected to the first forward / reverse transmission rod 88 and a bell. The crank 88a and the second forward / reverse speed changing rod 88b are connected to a traveling speed operating shaft 90 of the continuously variable transmission 21 for traveling through a traveling speed operating lever 89.

Further, at the front end of the forward / reverse transmission plate 87, a returning mechanism 84 for returning the forward / reverse transmission lever 8 to the neutral position is connected. The retracting mechanism 84 is configured substantially the same as the retracting member urging body 72, and the cylinder side is fixed to the machine body frame 2 and the screw rod side is connected to the forward / reverse transmission plate 87. Is different.

A forward / backward movement detection sensor SE is interlocked with the forward / backward movement shift lever 8, and the forward / backward movement detection sensor SE is connected.
Is a switch support plate 91 connected to the upper end of the forward / reverse speed change lever support 85, and the forward switch is attached to the switch support plate 91.
Attach the 93 and reverse switch 94 to move the forward / backward speed change lever 8
Is operated to the forward side, the forward end of the forward / reverse transmission plate 87 and the forward switch 93 come into contact with each other, and only the forward switch 93 is turned on. When the forward / reverse shift lever 8 is operated to the reverse side, The rear end of the transmission plate 87 and the reverse switch 94 come into contact with each other so that only the reverse switch 94 is turned on, and both switches 93 and 94 are turned off at the neutral position. Connect to the electromagnetic hydraulic directional control valve 92 that is connected to the hydraulic cylinder 83, and switch the oil passage of the electromagnetic hydraulic directional control valve 92 according to the detection output of each switch 93, 94 so that the tilt hydraulic cylinder 83 can be expanded and contracted. I have to.

The embodiment of the present invention is configured as described above, and the power is transmitted to the traveling continuously variable transmission 21 and the steering continuously variable transmission 20 by the engine 17, and the forward / reverse shift lever is used. 8 is operated, the continuously variable transmission 21 drives the auxiliary transmission 33 of the rear mission 19 and the left and right planetary gear mechanisms 40L, 40R of the front mission 18 at a speed corresponding to the operation amount of the forward / reverse shift lever 8. Through the left and right drive wheels of the left and right running parts 1L, 1R
By driving L and 11R, the agricultural tractor TR can be moved back and forth at a speed corresponding to the amount of operation of the forward / backward speed change lever 8.

By operating the sub-transmission unit 33 to change the gear ratio, it is possible to cope with a wide range of traveling speeds within the efficient rotational speed range of the continuously variable transmission 21 for traveling.

Further, when the steering wheel 6 is operated to operate the steering continuously variable transmission 20, the action of the gear mechanism 48 causes the left and right sun gears 49L, 40L of the left and right planetary gear mechanisms 40L, 40R to operate.
Since 49R rotates in opposite directions, left and right drive wheels 11L, 11R
The agricultural tractor TR can be turned by complementarily increasing / decreasing the rotational speed of.

Next, the operation of the steering device ST will be described.
When the steering wheel 6 is operated, the steering shaft
The rack 61 meshed with the pinion 62 at the lower end 56 slides in the direction corresponding to the operating direction of the steering wheel 6.

At this time, one of the forward / reverse switches 93, 94 is turned on depending on the operation direction of the forward / reverse shift lever 8,
The tilting hydraulic cylinder 83 is operated via the electromagnetic hydraulic directional control valve 92, and the tilting body 63 in the steering box 58 is tilted via the tilting shaft 78 and the ball spline 79. The inserted operation pin 66 moves along a locus substantially orthogonal to the movement locus of the rack 61 and by an amount corresponding to the operation amount of the steering wheel 6, so that the internal actuation lever 65, the actuation shaft 64, the external actuation lever 68, and Steering continuously variable transmission 20 via a connecting rod 69
From the variable displacement hydraulic pump, which was transmitted to 70 and had a discharge amount of zero until then, to the continuously variable transmission for steering 20 at a rotation speed corresponding to the operation amount of the steering wheel 6.
Output via the gear mechanism 48 and the left and right planetary gear mechanisms 40L, 40
Rotate the left and right sun gears 49L and 49R of R.

As described above, the steering gear 6 is operated through the tilting body 63 which changes the tilting direction according to the direction of operation of the forward / reverse speed change lever 8. By transmitting to the shaft 70, the agricultural tractor TR can be turned in the same direction as the turning direction of the steering wheel 6 regardless of the forward / backward movement of the agricultural tractor TR.

When the steering wheel 6 is linked to the steering gear shifting operation shaft 70 of the steering continuously variable transmission without interposing the tilting body 63, the steering wheel 6 of the steering wheel 6 can be moved in either forward or reverse direction. The turning direction and the turning direction of the agricultural tractor TR are opposite to each other, which makes steering operation extremely difficult.

When the forward / reverse shift lever 8 is in the neutral state, that is, when the machine is at rest, neither of the forward / reverse switches 93 and 94 of the forward / reverse detection sensor SE outputs. The hydraulic pressure is released, and the tilting shaft 78 is returned to the neutral position by the returning mechanism 84. In this state, since the tilting body 63 is not tilted to either the forward or backward direction, the operating pin 66 maintains the neutral position even when the steering wheel 6 is rotated, so that the steering continuously variable transmission 20 is stopped. The state is maintained, and therefore, the aircraft does not turn.

Further, by the lock mechanism 51 of the gear mechanism 48,
By fixing the left and right sun gears 49L and 49R, the left and right drive wheels 11L and 11R
Agricultural tractor
The straightness of TR can be improved.

[0037]

According to the present invention, the following effects can be obtained.

[0038]

According to the first aspect of the present invention, that is, by providing the gear mechanism with the lock mechanism, the left and right sun gears have the same rotational speed and the left and right traveling portions have the same traveling speed. It is possible to improve the
Further, when one of the left and right running portions enters muddy or the like and cannot run, the right and left running portions are directly connected by the lock mechanism, so that the left and right running portions can be easily escaped from the muddy or the like.

By the structure according to claim 2, that is, each continuously variable transmission is composed of the variable displacement hydraulic pump and the constant displacement hydraulic motor, the operation is simple and
It is possible to continuously change the traveling speed and turn.

[0040]

[0041]

[0042]

[Brief description of drawings]

FIG. 1 is an overall side view of an agricultural tractor including a traveling unit drive device according to the present invention.

FIG. 2 is a schematic plan view showing a schematic configuration of the traveling unit drive device.

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

FIG. 4 is a partial cross-sectional side view showing the configuration of a front mission.

FIG. 5 is a partial cross-sectional plan view showing the configuration of a front mission.

FIG. 6 is a partial cross-sectional side view showing the configuration of a rear mission.

FIG. 7 is a side view of the steering device.

FIG. 8 is a front view of the steering device.

FIG. 9 is a sectional side view of a steering gear box.

FIG. 10 is a sectional front view of a steering gear box.

FIG. 11 is a sectional plan view of a steering gear box.

[Explanation of symbols] DR drive unit 1L, 1R Left and right running section 20 Steering continuously variable transmission 20b output shaft 21 continuously variable transmission for traveling 21b Output shaft 33 Sub transmission unit 40L, 40R Left and right planetary gear mechanism 41L, 41R Left and right planetary gears 43L, 43R Left and right outer gear 48 gear mechanism 49L, 49R Left and right sun gear 51 Lock mechanism

─────────────────────────────────────────────────── --- Continuation of the front page (56) References JP-A-3-169745 (JP, A) JP-A-6-270833 (JP, A) JP-A-9-76931 (JP, A) Actual development Sho-58- 143769 (JP, U) Actual flat 7-9681 (JP, U) Actual flat 4-90462 (JP, U) Actual flat 4-72078 (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB name) B62D 11/00

Claims (2)

(57) [Claims] 1. A continuously variable transmission for traveling (21) is interlockingly connected to an engine (17), and a left and right traveling section (1L) is connected to the continuously variable transmission for traveling (21).
(1R) drive shafts (38L) (38R)
8L) and (38R) are driven in the same rotational direction by the traveling continuously variable transmission (21), while the engine (17) is linked to the steering continuously variable transmission (20) to provide the same steering. Each drive shaft of left and right running parts (1L) (1R) on the continuously variable transmission (20)
(38L) and (38R) are interlocked and linked, and the drive shafts (38L) and (38R) are driven by the steering continuously variable transmission (20) in opposite directions to each other. ) (20) by the rotational speed is increased or decreased to enable reduction sensitization pivot body of the drive shaft (38L) (38R), moreover, the output shaft of the running CVT (21) and (21b) sub
Interlockingly connected to the speed change unit (33) , connect the auxiliary speed change unit (33) to the left and right planetary teeth.
Linked to the left and right outer gears (43L) (43R) of the car mechanism (40L) (40R)
Connect the output shaft (20b) of the steering continuously variable transmission (20 ) to each other.
Via the gear mechanism (48) that transmits in the opposite direction of rotation
Left and right planetary gear mechanism (40L) (40R) left and right sun gear (49L) (49R)
Interlocking connected to the left and right plug of the right and left planetary gear mechanisms (40L) (40R)
The Netarigiya (41L) left and right traveling unit (41R), respectively (1L) (1R)
In a traveling drive device for an agricultural tractor connected in an interlocking manner, the gear mechanism (48) is rotated left and right in the same direction.
A traveling drive device for an agricultural tractor, which is provided with a lock mechanism (51) . 2. Each of the continuously variable transmissions (20) (21) is static.
Hydraulic type, variable displacement hydraulic pump and constant displacement hydraulic motor
Traveling drive device of an agricultural tractor according to claim 1, characterized by being configured by the motor.