JP2004067093A - Agricultural tractor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent damage to an agricultural field by smoothening a swing in an agricultural tractor. <P>SOLUTION: According to this invention, a traveling transmission gear is interlinked and connected with an engine, and each drive shaft of right and left travel parts is interlinked and connected with the same traveling transmission gear, so that each drive shaft is driven in the same rotational direction by the traveling transmission gear. A steering transmission gear is interlinked and connected with the engine, and each drive shaft of right and left travel parts is interlinked and connected with the same steering transmission gear, so that each drive shaft is driven in a reverse rotational direction by the steering transmission gear. The number of rotations of each drive shaft is increased or decreased by both transmission gears, to make a machine body swingable, acceleratable and deceleratable. A steering wheel is interlinked and connected with the steering transmission gear, while a forward and backward transmission lever is interlinked and connected with the traveling transmission gear. <P>COPYRIGHT: (C)2004,JPO

Description

The present invention relates to an agricultural tractor.

2. Description of the Related Art Conventionally, in agricultural tractors, there is a type in which a continuously variable transmission that is interlocked with a left and right traveling unit has a different drive speed to turn an airframe (for example, see Patent Document 1).
JP-A-7-81608

However, since the left and right continuously variable transmissions are linked to the left and right continuously variable transmissions to operate the left and right continuously variable transmissions individually, the steering operation is difficult. Poor straightness due to individual differences, irregularities in the left and right operation mechanisms that operate the left and right continuously variable transmission, and backlash, and turning smoothly because the left and right continuously variable transmissions are controlled independently of each other Therefore, there is a problem that the field scene is damaged.

Therefore, in the present invention, a driving transmission is interlocked to the engine, and the driving shafts of the left and right traveling parts are interlocked to the driving transmission, and the driving shafts are mutually rotated in the same rotational direction by the driving transmission. The steering transmission is linked to the engine, and the left and right drive shafts are linked to the steering transmission, and the drive shafts are reversed by the steering transmission. Driving in the rotation direction, the speed of each drive shaft can be increased or decreased by both transmissions to enable the aircraft to turn and increase / decrease, and the steering wheel is linked to the steering transmission, while the forward / reverse transmission lever is used for traveling. Linked to the transmission.

In addition, in the present invention, the drive shafts of the left and right traveling units are linked to the traveling transmission via the transmission unit.

According to the present invention, a front transmission and a rear transmission are provided on the fuselage, the transmission section is provided on the rear transmission, and the front transmission is connected to the rear transmission via an interlocking shaft.

Further, in the present invention, a power take-off clutch is disposed on the rear transmission, and a power take-off shaft is interlocked to the power take-off clutch.

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

That is, the driving transmission is interlocked to the engine, the driving shafts of the left and right traveling units are interlocked to the driving transmission, and the driving shafts are driven in the same rotational direction by the driving transmission. The steering transmission is linked to the engine, and the drive shafts of the left and right running parts are linked to the steering transmission, and the drive shafts are driven in opposite directions by the steering transmission. An agricultural tractor capable of increasing and decreasing the number of revolutions of each drive shaft by means of both transmissions so that the aircraft body can be turned and accelerated and decelerated, wherein a steering wheel is interlocked with a steering transmission while a forward / reverse transmission lever is provided. Is an agricultural tractor interlockingly connected to a traveling transmission, wherein the steering wheel is interlockingly connected to the steering transmission, while the forward / reverse shift lever is interlockingly connected to the traveling transmission, so that How to rotate left and right traveling parts by transmission For example, in the state where the body is driven forward by driving forward rotation and the body is moving forward, the rotation direction of the left traveling unit is driven forward by the steering transmission, for example, and the rotation direction of the right traveling unit is reversed. When rotationally driven, the left traveling unit is speed-driven by the two transmissions, and the right traveling unit is speed-reduced by the two transmissions, so that the body can smoothly turn right.

As described above, the left and right traveling parts can be complementarily accelerated and decelerated by the two transmissions during the turning operation of the body, so that the body can be smoothly turned from a gentle turn to a sharp turn, and at the time of turning, It is possible to prevent a problem that the field is damaged by the left and right traveling parts.

In addition, the turning of the body can be controlled with one steering wheel, so that the operation is easy, and since the above-described problems caused by the unevenness of the left and right operation mechanisms and the backlash are eliminated, the straight traveling property is improved, Further, since the delicate steering operation is possible with the steering wheel, the aircraft can be smoothly turned at an arbitrary turning radius.

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

FIG. 1 is a side view of an agricultural tractor TR provided with a traveling drive device DR according to the present invention. The agricultural tractor TR is a front upper surface of a body frame 2 equipped with crawler-type left and right traveling units 1L and 1R. A motor unit 3 is mounted on the vehicle, and a cabin 4 is mounted behind the motor unit 3. An operating unit 5 is disposed in the cabin 4.

The driving unit 5 has a steering wheel 6 disposed at the front part so as to be steerable and rotatable, and a seat 7 disposed behind the steering wheel 6 at a predetermined interval, and a forward / reverse transmission lever 8 can be tilted forward and backward to the right of the seat. It is standing up. In the drawing, reference numeral 9 denotes a traveling unit frame, 10 denotes a crawler belt, 11 denotes a drive wheel, 12 denotes an idle wheel, 13 denotes a lower wheel, 14 denotes an upper wheel, 15 denotes a lower link, and 16 denotes a work implement elevating mechanism.

2 and 3 show the arrangement of the traveling drive device DR. The engine 17, the front transmission 18, and the rear transmission 19 mounted on the motor unit 3 are arranged in this order from the front along the front-rear center line of the fuselage. A hydrostatic steering continuously variable transmission 20 composed of a variable displacement hydraulic pump and a constant displacement hydraulic motor is mounted on the rear surface of the front transmission 18, and a variable displacement hydraulic pump is mounted on the front of the rear transmission 19. A hydrostatic continuously variable transmission 21 composed of a hydraulic motor and a constant displacement hydraulic motor is mounted, and each part of the traveling drive device DR will be described in the order of power transmission.

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

On the other hand, the output shaft 21b of the continuously variable transmission for traveling 21 is operatively connected to a rear transmission output shaft 34 via a traveling clutch 32 and an auxiliary transmission portion 33 capable of neutral and three-stage shifting. The front end of 34 is interlockingly connected to the rear end of a front input shaft 36 supported on the rear surface of the front transmission 18 via universal joints 26, 26 and a second interlocking shaft 35. Through the formed traveling mesh bevel gear 37, it is interlockingly connected to an intermediate shaft 39 supported between left and right traveling unit drive shafts 38L and 38R.

The left and right traveling unit drive shafts 38L and 38R are connected to the left and right planetary gear mechanisms 40L and 40R disposed on the left and right sides of the intermediate shaft 39 via the left and right planetary gears 41L and 41R and the left and right cages 42L and 42R. The left and right outer gears 43L, 43R of the left and right planetary gear mechanisms 40L, 40R are fitted to the left and right ends of the intermediate shaft 39, respectively.

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 fitted to the steering driving bevel gear 45 at the inner end of the left and right steering shafts 46L, 46R. The left and right passive passive bevel gears 47L, 47R are engaged to form a differential gear mechanism 48, and the outer ends of the left and right steering shafts 46L, 46R and the left and right sun gears 49L, of the left and right planetary gear mechanisms 40L, 40R. The left and right steering gears 50L and 50R are interlockingly connected to the 49R and the splines 51L and 51R formed on the inner ends of the left and right steering shafts 46L and 46R, and can be fitted to the splines 51L and 51R. A differential lock mechanism 51 comprising a sleeve 51a is provided to prevent rotation of the left and right steering shafts 46L, 46R. In FIG. 6, reference numeral 52 denotes a brake.

Next, the steering device ST will be described with reference to FIGS.

As shown in FIGS. 7 and 8, the steering device ST is provided with a stay 54 projecting from the front inner surface of the cabin 4 and attached to a steering post 55 fixed to the rear end of the stay 54 in a front-low and rear-high inclination state. A steering shaft 56 having a steering wheel 6 attached to the upper end thereof is rotatably inserted, and a lower end of the steering shaft 56 is attached to the lower surface of the floor of the cabin 4 via universal joints 26, 26 and an extension shaft 57. It is linked to an operation input shaft 59 protruding from the upper surface of 58.

(4) A steering acceleration / deceleration mechanism SA is provided inside the steering box 58 so that the rotational speed of the continuously variable steering transmission 20 is 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 60 having a rack support shaft 60 provided in the steering box 58 in the left-right direction and a rack 61 attached to the front surface of the rack support shaft 60. The body 61a is slidably fitted to the outside of the rack 61, and a pinion 62 formed at the lower end of the operation input shaft 59 is meshed with the rack 61, and a lower opening of the rack support 61a has a substantially U-shaped cross section. An operating pin projecting from the tip of an internal operating lever 65 connected to the inner end of an operating shaft 64 through which the bottom wall of the steering box 58 is inserted, while pivoting the center of the tilting body 63 so that it can rotate left and right. 66 is inserted into the opening of the tilting body 63 via a ball bearing 67, an external operating lever 68 is connected to the outer end of the operating shaft 64, and the external operating lever 68 is connected to the connecting rod 69 and the steering shift lever. 70a through the steering speed change operation shaft 70 of the continuously variable transmission 20 for steering. They are interlocked.

Further, a screw rod 71 extending in the left-right direction is installed in the steering box 58, and a return seat urging member 72 is externally fitted to the screw rod 71. The return seat urging member 72 is a cylindrical body fixed to the rack 61. A coil spring 74 is housed in 73, and both ends of the coil spring 74 are fixed with washers 75, 75 and retaining rings 76, 76 so as to be slidable inward and non-slidable outward, respectively. The return seat urging member 72 is supported by adjusting nuts 77, 77 screwed to the outside positions of the washers 75, 75.

Further, a forward / reverse switching mechanism SB is provided in the steering box 58, and the rotation direction of the output of the continuously variable transmission 20 for steering is reversed by interlocking with the forward / backward tilting of the forward / reverse speed change lever 8, which will be described later. The body is turned in the turning direction of the steering wheel 6 regardless of the traveling direction.

The forward / reverse switching mechanism SB has a tilting shaft 78 extending in the left-right direction rotatably mounted, and a sliding body 80 is externally fitted to the tilting shaft 78 via a ball spline 79 so as to be slidable left and right. The downwardly extending portion 80a of 80 and the tilting body 63 are interlocked and connected via a connecting rod 81, and a tilting operation lever 82 is connected to the protruding end of the tilting shaft 78, and a fixed end is connected to the tilting operation lever 82. An operating end of a hydraulic cylinder for tilting 83 pivotally attached to the body frame 2 and a return mechanism 84 for returning the tilting shaft 78 to a neutral position are interlockingly connected.

As shown in FIGS. 7 and 8, the forward / reverse transmission lever 8 is connected to a forward / rearward transmission lever 8 via a support shaft 86 inserted through the upper end of a forward / reverse transmission lever support 85 erected on the right side of the seat 7 of the body frame 2. A substantially reverse T-shaped forward / rearward transmission plate 87 is connected to the support shaft 86 so as to be able to tilt back and forth freely, and the rear end of the forward / reverse transmission plate 87 is connected to a first forward / reverse transmission rod 88, a bell crank 88a, It is operatively connected to a traveling speed operating shaft 90 of the continuously variable transmission 21 through a second forward / reverse transmission rod 88b and a traveling speed operating lever 89.

A return mechanism 84 for returning the forward / reverse transmission lever 8 to the neutral position is connected to the front end of the forward / reverse transmission plate 87. The return mechanism 84 has substantially the same configuration as the return biasing body 72, and has the same structure as that described above except that the cylinder side is fixed to the body frame 2 and the screw side is connected to the forward / reverse transmission plate 87. Is different.

A forward / backward shift detection sensor SE is linked to the forward / backward shift lever 8. The forward / backward shift detection sensor SE has a switch support plate 91 connected to the upper end of the forward / backward shift lever support 85. A forward switch 93 and a reverse switch 94 are mounted on the switch support plate 91. When the forward / reverse transmission lever 8 is operated to the forward side, the forward end of the forward / reverse transmission plate 87 contacts the forward switch 93 to move forward. When only the switch 93 is turned on and the forward / reverse transmission lever 8 is operated to the reverse side, the rear end of the forward / reverse transmission plate 87 contacts the reverse switch 94, and only the reverse switch 94 is turned on. Both switches 93, 94 are turned off, and each switch 93, 94 is connected to an electromagnetic hydraulic directional control valve 92 connected to and connected to the tilt hydraulic cylinder 83, and the detection output of each switch 93, 94 is used. Switching the oil path of the electromagnetic hydraulic directional control valve 92 Te, and so as to stretch activated tilt hydraulic cylinder 83.

In the embodiment of the present invention, the power is transmitted to the continuously variable transmission 21 for traveling and the continuously variable transmission 20 for steering by the engine 17 and the forward / reverse shift lever 8 is operated. Then, the continuously variable transmission 21 for traveling travels through the auxiliary transmission portion 33 of the rear transmission 19 and the left and right planetary gear mechanisms 40L and 40R of the front transmission 18 at a speed corresponding to the operation amount of the forward / reverse transmission lever 8, By driving the left and right drive wheels 11L, 11R of the traveling units 1L, 1R, the agricultural tractor TR can be moved forward and backward at a speed corresponding to the operation amount of the forward / reverse shift lever 8.

操作 Further, 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 rotation speed range of the continuously variable transmission 21 for traveling.

When the steering continuously variable transmission 20 is operated by operating the steering wheel 6, the left and right sun gears 49L and 49R of the left and right planetary gear mechanisms 40L and 40R rotate in opposite directions due to the action of the differential gear mechanism 48. Therefore, the agricultural tractor TR can be turned by complementarily increasing and decreasing the rotational speed of the left and right drive wheels 11L and 11R.

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

At this time, depending on the operation direction of the forward / reverse speed change lever 8, one of the forward / backward switches 93 and 94 is turned on, and the tilting hydraulic cylinder 83 is operated via the electromagnetic hydraulic direction control valve 92, so that the tilting shaft 78 and the ball spline Since the tilting body 63 in the steering box 58 is tilted via 79, the operating pin 66 inserted into the opening of the tilting body 63 has a trajectory substantially orthogonal to the movement trajectory of the rack 61, and The wheel 6 is moved by an amount corresponding to the operation amount of the wheel 6, and is moved to the steering shift operation shaft 70 of the continuously variable transmission 20 via the internal operation lever 65, the operation shaft 64, the external operation lever 68, and the connecting rod 69. The variable speed hydraulic pump, which has been transmitted and has been in the neutral state until then and has a discharge amount of zero, outputs the continuously variable steering transmission 20 at a rotation speed corresponding to the operation amount of the steering wheel 6, and outputs the differential. Left and right planetary teeth via gear mechanism 48 Mechanism 40L, the left and right sun gears 49L of 40R, rotate the 49R.

In this manner, the operation of the steering wheel 6 is transmitted to the steering speed change operation shaft 70 of the steering continuously variable transmission 20 via the tilting body 63 that changes the tilt direction according to the operation direction of the forward-reverse speed change lever 8. By transmitting the information, 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 shift operation shaft 70 of the continuously variable transmission for steering without the interposition of the tilting body 63, the turning direction of the steering wheel 6 in any of forward and backward traveling And the turning direction of the agricultural tractor TR is reversed, and the steering operation becomes extremely difficult.

Further, when the forward / reverse shift lever 8 is in the neutral state, that is, when the body is stopped, both the forward / reverse switches 93 and 94 of the forward / backward detection sensor SE do not output, so the hydraulic pressure in the tilt hydraulic cylinder 83 is reduced. When released, the tilting shaft 78 is returned to the neutral position by the return mechanism 84. In this state, since the tilting body 63 is not tilted to any side in the forward or backward direction, the operation pin 66 maintains the neutral position even when the steering wheel 6 is rotated, so that the continuously variable steering transmission 20 stops. The state is maintained, and therefore, no turning of the aircraft is performed.

In addition, the differential lock mechanism 51 of the differential gear mechanism 48 fixes the left and right sun gears 49L and 49R and makes the rotation speeds of the left and right drive wheels 11L and 11R the same, thereby improving the straightness of the agricultural tractor TR. be able to.

1 is an overall side view of an agricultural tractor including a traveling unit driving device according to the present invention. FIG. 2 is a schematic plan view illustrating a schematic configuration of the traveling unit driving device. FIG. 2 is a plan view showing the configuration of the traveling unit driving device. FIG. 2 is a partial cross-sectional side view showing the configuration of the front transmission. FIG. 2 is a partial cross-sectional plan view showing a configuration of a front mission. FIG. 2 is a partial cross-sectional side view showing the configuration of the rear transmission. The side view of a steering device. The front view of a steering device. Sectional side view of a steering gear box. Sectional front view of a steering gear box. Sectional plan view of a steering gear box.

Explanation of reference numerals

DR Travel drive SA Steering acceleration / deceleration mechanism SB Forward / reverse switching mechanism SE Forward / backward detection sensor 1L, 1R Left / right traveling section 6 Steering wheel 8 Forward / reverse transmission lever 20 Steering continuously variable transmission 21 Continuously variable transmission for traveling 58 Steering box

Claims (3)

The driving transmission is linked to the engine (17), and the driving shafts (38L) and (38R) of the left and right running parts (1L) (1R) are linked to the driving transmission and linked to the driving shaft (38L). ) (38R) are driven in the same rotational direction by the traveling transmission, while a steering transmission is interlocked to the engine (17), and the left and right traveling parts (1L) (1R ), The drive shafts (38L) and (38R) are connected in an interlocked manner, and the drive shafts (38L) and (38R) are driven in opposite directions by a steering transmission. (38L) (38R) The number of revolutions can be increased / decreased to make the aircraft turnable and decelerated, and the steering wheel (6) is linked to the steering transmission, while the forward / reverse transmission lever (8) is used for the traveling transmission. Agricultural tractor steering system linked to
A steering device for an agricultural tractor, wherein the drive shafts (38L) and (38R) of the left and right traveling units (1L) and (1R) are interlocked to a traveling transmission via a transmission unit. A front transmission (18) and a rear transmission (19) are arranged on the fuselage, the transmission section is arranged on this rear transmission (19), and the front transmission (18) is linked to the rear transmission (19) by an interlocking shaft. The agricultural tractor steering apparatus according to claim 1, wherein the agricultural tractor steering apparatus is interlocked and connected. Agriculture according to claim 2, characterized in that a power take-off clutch (29) is arranged on the rear transmission (19) and a power take-off shaft (31) is interlockedly connected to the power take-off clutch (29). Tractor steering system.

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