JP3626145B2 - Agricultural tractor steering device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a steering device for an agricultural tractor.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, there is an agricultural tractor in which the body is turned by varying the driving speed of a continuously variable transmission that is linked and connected to the left and right traveling units.
[0003]
[Problems to be solved by the invention]
However, the left and right continuously variable transmissions are linked to the left and right steering levers, and the left and right continuously variable transmissions are individually operated. Due to individual differences and unevenness and backlash of the left and right operating mechanisms that operate the left and right continuously variable transmission, the straight travel is poor, and the left and right continuously variable transmissions are controlled independently of each other, so turning is smooth. Therefore, there is a problem that the field scene is damaged.
[0004]
[Means for Solving the Problems]
Therefore, in the present invention, the driving continuously variable transmission is linked to the engine, the drive shafts of the left and right traveling portions are linked to the driving continuously variable transmission, and the driving shafts are connected to the driving continuously variable transmission. The steering continuously variable transmission is linked to the engine, and the drive shafts of the left and right traveling parts are linked to the steering continuously variable transmission. An agricultural tractor that can be driven in a reverse rotation direction by a steering continuously variable transmission and that can increase / decrease the speed of the vehicle by turning the speed of each drive shaft with both transmissions. Is linked to the steering continuously variable transmission via the steering speed increase / decrease mechanism, while the forward / reverse shift lever is linked to the traveling continuously variable transmission, and the forward / reverse operation of the forward / reverse shift lever is operated. A forward / reverse switching mechanism linked to the Is matched with the turning direction of the turning direction and the fuselage of the ring wheel, moreover, the agricultural tractor, characterized in that disposed between the forward-reverse switching mechanism the steering for acceleration and deceleration mechanism inside the steering gear box A steering device is provided.
[0005]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described with reference to the drawings.
[0006]
FIG. 1 is a side view of an agricultural tractor TR provided with a traveling drive apparatus DR according to the present invention. The agricultural tractor TR is an upper front portion of a body frame 2 equipped with crawler-type left and right traveling sections 1L and 1R. The motor unit 3 is mounted on the rear side, the cabin 4 is mounted on the rear side, and the driving unit 5 is disposed in the cabin 4.
[0007]
The driving unit 5 has a steering wheel 6 disposed at the front thereof so that the steering wheel 6 can be freely rotated, a seat 7 is disposed behind the steering wheel 6 with a predetermined interval, and a forward / reverse speed change lever 8 can be tilted forward and backward on the right side of the seat. Is standing. In the figure, 9 is a traveling unit frame, 10 is a crawler belt, 11 is a drive wheel, 12 is an idler wheel, 13 is a lower wheel, 14 is an upper wheel, 15 is a lower link, and 16 is a work implement lifting mechanism.
[0008]
2 and 3 show the arrangement of the travel drive device DR, arranged in the order of the engine 17, the front mission 18, the rear mission 19 mounted on the prime mover unit 3 from the front along the front-rear center line of the aircraft, 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 mission 18, and a variable displacement hydraulic pump and A hydrostatic traveling continuously variable transmission 21 as a traveling transmission constituted by a constant displacement hydraulic motor is attached, and each part of the traveling drive apparatus DR will be described in the order of power transmission.
[0009]
4 and 5 show a front mission 18 and FIG. 6 shows a rear mission 19. The front mission input shaft 23 linked to the engine 17 via a double hook joint 22 is connected to the steering via a gear train 25. Universally connected to the input shaft 20a of the continuously variable transmission 20 and universal joints 26 and 26 provided between the front mission 18 and the rear mission 19 at the rear end of the input shaft 20a and the first interlocking shaft 27. Via the front end of the input shaft 21a of the continuously variable transmission 21 for traveling, the rear end of the input shaft 21a is capable of neutral and two-stage shifting with a power take-off clutch 29 provided in the rear mission 19. Are connected to a power take-off shaft 31 through a power take-off transmission 30 and a meshing reduction gear 30a.
[0010]
On the other hand, the output shaft 21b of the traveling continuously variable transmission 21 is linked to the rear mission output shaft 34 via the traveling clutch 32 and a sub-transmission unit 33 capable of neutral and three-speed shifting, and the rear mission output shaft. The front end of 34 is linked to the rear end of the front input shaft 36 pivotally supported on the rear surface of the front mission 18 via the universal joints 26 and 26 and the second interlocking shaft 35. And an intermediate shaft 39 that is pivotally supported between the left and right traveling unit drive shafts 38L and 38R via a traveling meshing bevel gear 37 formed in the above.
[0011]
The left and right traveling unit drive shafts 38L and 38R are connected to the left and right traveling units 1L and 1R via the left and right planetary gears 41L and 41R and the left and right cages 42L and 42R of the left and right planetary gear mechanisms 40L and 40R disposed on the left and right sides of the intermediate shaft 39, respectively. The left and right drive wheels 11L and 11R are connected to each other, and 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, respectively.
[0012]
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 fitted to the inner ends of the left and right steering shafts 46L and 46R. The left and right steering passive bevel gears 47L and 47R are meshed to form a differential gear mechanism 48, and 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, 49R and the left and right steering gears 50L and 50R are interlocked and connected to each other, and can be fitted to the splines 51L and 51R formed on the inner ends of the left and right steering shafts 46L and 46R and the splines 51L and 51R. A differential lock mechanism 51 comprising a sleeve 51a is provided to prevent the left and right steering shafts 46L and 46R from rotating. In FIG. 6, 52 is a brake.
[0013]
Next, the steering apparatus ST will be described with reference to FIGS.
[0014]
As shown in FIGS. 7 and 8, the steering device ST has a stay 54 that protrudes from the inner surface of the front side of the cabin 4, and is attached to a steering post 55 that is fixed to the rear end of the stay 54 in a tilted state of front and rear and rear height. The steering shaft 56 with the steering wheel 6 attached to the upper end is rotatably inserted, and the lower end of the steering shaft 56 is attached to the lower surface of the cabin 4 via the universal joints 26, 26 and the extension shaft 57. An operation input shaft 59 protruding from the upper surface of 58 is interlocked and connected.
[0015]
A steering acceleration / deceleration mechanism SA is provided inside the steering box 58 so that the rotational speed of the steering continuously variable transmission 20 is proportional to the operation amount of the steering wheel 6.
[0016]
As shown in FIGS. 9 to 11, the steering speed increasing / decreasing mechanism SA has a rack support shaft 60 in which a rack support shaft 60 is installed in the left-right direction in the steering box 58, and a rack 61 is attached to the front surface of the rack support shaft 60. The body 61a is slidably fitted to the left and right, and the rack 61 is engaged with a pinion 62 formed at the lower end of the operation input shaft 59, and the lower surface of the rack support 61a has a substantially U-shaped cross section. The center part of the tilting body 63 is pivotally pivoted in the left-right direction, and the operating pin projecting from the tip of the internal operating lever 65 connected to the inner end of the operating shaft 64 inserted through the bottom wall of the steering box 58 is provided. 66 is inserted into the opening of the tilting body 63 via a ball bearing 67, and an external operating lever 68 is connected to the outer end of the operating shaft 64. The external operating lever 68 and the connecting rod 69 are steered and shifted. Via the bar 70a is operatively connected to the steering gear shifting operation shaft 70 of the steering for a continuously variable transmission 20.
[0017]
Further, a screw 71 extending in the left-right direction is installed in the steering box 58, and a reverse seat biasing body 72 is externally fitted to the screw 71, and the reverse seat biasing body 72 is a cylindrical body fixed to the rack 61. The coil spring 74 is housed in 73, and both ends of the coil spring 74 are fixed to the inside by means of washers 75, 75 and retaining rings 76, 76 so as to be slidable in the inner direction and non-slidable in the outer direction. The reverse seat urging body 72 is supported by adjusting nuts 77 and 77 screwed to the outer positions of the washers 75 and 75.
[0018]
Further, by providing a forward / reverse switching mechanism SB in the steering box 58 and reversing the rotation direction of the steering continuously variable transmission 20 in conjunction with the forward / backward tilting of the forward / reverse transmission lever 8 to be described later, The body is turned in the turning direction of the steering wheel 6 regardless of the advance.
[0019]
The forward / reverse switching mechanism SB includes a tilting shaft 78 extending in the left-right direction so as to be rotatable, 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. A downward 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 portion of the tilting shaft 78, and the tilting operation lever 82 is fixed to the fixed end. The operating end of the tilting hydraulic cylinder 83 pivotally attached to the body frame 2 and the reverse seat mechanism 84 for returning the tilting shaft 78 to the neutral position are interlocked and connected.
[0020]
Further, as shown in FIGS. 7 and 8, the forward / reverse speed change lever 8 is moved via a support shaft 86 inserted through the upper end portion of the forward / reverse speed change lever support body 85 erected on the right side of the seat 7 of the body frame 2. A forward / reverse transmission plate 87 having a substantially inverted T shape is connected to the support shaft 86 so as to freely tilt forward and backward, and a rear end of the forward / rearward transmission plate 87 is connected to a first forward / reverse transmission rod 88, a bell crank 88a, The second forward / reverse speed change rod 88 b and the travel speed operation lever 89 are linked to the travel speed operation shaft 90 of the continuously variable transmission 21 for travel.
[0021]
Further, a reverse seat 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 reverse seating mechanism 84 is configured in substantially the same manner as the reverse seat biasing body 72, and 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.
[0022]
A forward / reverse detection sensor SE is linked to the forward / reverse transmission lever 8, and the forward / reverse detection sensor SE is provided with a switch support plate 91 at the upper end of the forward / reverse transmission lever support 85. When a forward switch 93 and a reverse switch 94 are attached to the switch support plate 91 and the forward / reverse transmission 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 to advance. When only the switch 93 is turned on and the forward / reverse transmission lever 8 is operated to the reverse side, the rear end portion of the forward / reverse transmission plate 87 and the reverse switch 94 come into contact with each other, 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 electrohydraulic direction control valve 92 communicatively coupled to the tilting hydraulic cylinder 83. The detection output of 93 and 94 by switching the oil passage electromagnetic hydraulic directional control valve 92, so as to stretch activated tilt hydraulic cylinder 83.
[0023]
The embodiment of the present invention is configured as described above. 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 8 is operated. Then, the continuously variable transmission 21 for traveling passes through the auxiliary transmission portion 33 of the rear mission 19 and the left and right planetary gear mechanisms 40L and 40R of the front mission 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 portions 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.
[0024]
Further, by operating the auxiliary transmission unit 33 and changing 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.
[0025]
Further, 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 increasing or decreasing the rotational speeds of the left and right drive wheels 11L and 11R in a complementary manner.
[0026]
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.
[0027]
At this time, one of the forward / reverse switches 93 and 94 is turned on by the operation direction of the forward / reverse shift lever 8 to operate the tilting hydraulic cylinder 83 via the electromagnetic hydraulic direction control valve 92, and the tilting shaft 78 and the ball spline are operated. 79, the tilting body 63 in the steering box 58 is tilted, so that the operating pin 66 inserted into the opening of the tilting body 63 has a trajectory substantially perpendicular to the movement trajectory of the rack 61 and the steering. It moves by an amount corresponding to the operation amount of the wheel 6, and moves to the steering shift operation shaft 70 of the steering continuously variable transmission 20 via the internal operation lever 65, the operation shaft 64, the external operation lever 68 and the connecting rod 69. Steering continuously variable transmission at a rotational speed corresponding to the operation amount of the steering wheel 6 from the variable displacement hydraulic pump that has been transmitted and was neutral until then and the discharge amount was zero The machine 20 outputs and rotates the left and right sun gears 49 L, 49 R of the left and right planetary gear mechanisms 40 L, 40 R via the differential gear mechanism 48.
[0028]
In this way, the steering wheel 6 is operated to the steering shift operation shaft 70 of the steering continuously variable transmission 20 via the tilting body 63 that changes the tilting direction according to the operation direction of the forward / reverse shift lever 8. By transmitting, 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.
[0029]
If the steering wheel 6 is linked to the steering speed change operation shaft 70 of the steering continuously variable transmission without using the tilting body 63, the turning direction of the steering wheel 6 in either case of forward / reverse travel. And the turning direction of the agricultural tractor TR is reversed, and the steering operation becomes extremely difficult.
[0030]
Further, when the forward / reverse shift lever 8 is in a neutral state, that is, when the aircraft is stopped, both the forward / reverse switches 93 and 94 of the forward / reverse detection sensor SE do not output, so the hydraulic pressure in the tilting hydraulic cylinder 83 is reduced. The tilting shaft 78 is returned to the neutral position by the reverse seating mechanism 84. In this state, since the tilting body 63 is not tilted forward or backward, the operating pin 66 holds 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 is not turned.
[0031]
Further, the right and left sun gears 49L and 49R are fixed by the differential lock mechanism 51 of the differential gear mechanism 48 and the rotation speeds of the left and right drive wheels 11L and 11R are made the same, thereby improving the straightness of the agricultural tractor TR. be able to.
[0032]
【The invention's effect】
According to the present invention, the following effects can be obtained.
[0033]
That is, according to the present invention, the driving continuously variable transmission is linked to the engine, the drive shafts of the left and right traveling parts are linked to the driving continuously variable transmission, and the driving shafts are connected to the driving continuously variable transmission. The steering continuously variable transmission is linked to the engine, and the drive shafts of the left and right traveling parts are linked to the steering continuously variable transmission. An agricultural tractor that can be driven in a reverse rotation direction by a steering continuously variable transmission and that can increase / decrease the speed of the vehicle by turning the speed of each drive shaft with both transmissions. Is linked to the steering continuously variable transmission via the steering speed increase / decrease mechanism, while the forward / reverse shift lever is linked to the traveling continuously variable transmission, and the forward / reverse operation of the forward / reverse shift lever is operated. A forward / reverse switching mechanism linked to the Is matched with the turning direction of the turning direction and the fuselage of the A ring wheel, moreover, it is disposed and the forward-reverse switching mechanism the acceleration and deceleration mechanism for steering the interior of the steering gear box.
[0034]
Accordingly, the rotational direction of the left and right traveling parts is driven by the traveling transmission, for example, in the state of being driven to rotate forward and the aircraft is traveling forward, and the rotational direction of the left traveling part is controlled by the continuously variable transmission for steering, for example. When the right traveling unit is driven to rotate in the forward direction and the rotational direction of the right traveling unit is rotated in the reverse direction, the left traveling unit is driven to increase the speed by both transmissions, and the right traveling unit is driven to decelerate by both transmissions to smoothly The aircraft can be turned to the right.
[0035]
At this time, since the left and right traveling units can be complementarily increased / decreased by both transmissions during the turning operation of the airframe, the airframe can smoothly turn from a slow turn to a sudden turn, Generation | occurrence | production of the malfunction of damaging a farm field by a traveling part can be prevented.
[0036]
And it is possible to control the turning of the aircraft with a single steering wheel, and the operation is easy, and the problems caused by the unevenness and backlash of the left and right operation mechanism described above are eliminated, so the straightness is improved, Further, since the steering wheel can perform a delicate steering operation, the airframe can be smoothly turned with an arbitrary turning radius.
[0037]
In addition, a forward / reverse switching mechanism that interlocks with forward / reverse operation of the forward / reverse speed change lever is provided so that the turning direction of the steering wheel coincides with the turning direction of the machine body.
[0038]
In this way, by making the turning direction of the steering wheel coincide with the turning direction of the airframe, the steering wheel can be turned in the direction in which it wants to turn regardless of the forward / backward direction of the airframe. It becomes easy and can increase safety.
[Brief description of the drawings]
FIG. 1 is an overall side view of an agricultural tractor provided with a traveling unit driving device according to the present invention.
FIG. 2 is a schematic plan view showing a schematic configuration of the traveling unit driving device.
FIG. 3 is a plan view showing a configuration of the traveling unit driving device.
FIG. 4 is a partial cross-sectional side view showing a configuration of a front mission.
FIG. 5 is a partial cross-sectional plan view showing a configuration of a front mission.
FIG. 6 is a partial cross-sectional side view showing a 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 cross-sectional side view of a steering gear box.
FIG. 10 is a cross-sectional front view of a steering gear box.
FIG. 11 is a cross-sectional plan view of a steering gear box.
[Explanation of symbols]
DR Traveling drive device SA Steering acceleration / deceleration mechanism SB Forward / reverse switching mechanism SE Forward / reverse detection sensor 1L, 1R Left / right traveling unit 6 Steering wheel 8 Forward / reverse shifting lever 20 Steering continuously variable transmission 21 Traveling continuously variable transmission 58 Steering box

Claims (1)

The driving continuously variable transmission (21) is linked to the engine (17), and the drive shafts (38L) (38R) of the left and right traveling parts (1L) (1R) are connected to the continuously variable transmission (21). The drive shafts (38L) and (38R) are driven in the same rotational direction by the traveling continuously variable transmission (21) while being linked to each other, while the engine (17) is driven by the continuously variable transmission (20). Are linked to each other, and the drive shafts (38L) (38R) of the left and right traveling parts (1L) (1R) are linked to the continuously variable transmission (20) for the same steering, so that each drive shaft (38L) (38R ) Are driven in the reverse rotation direction by the steering continuously variable transmission (20), and the rotational speed of each drive shaft (38L) (38R) is increased or decreased by both transmissions (21) (20). Agricultural tractor (B) capable of turning and decelerating
While the steering wheel (6) is linked to the steering continuously variable transmission (20) via the steering acceleration / deceleration mechanism (SA),
The forward / reverse transmission lever (8) is linked to the continuously variable transmission (21) for driving, and a forward / reverse switching mechanism (SB) is provided that is linked to the forward / reverse operation of the forward / reverse transmission lever (8). By the same forward / reverse switching mechanism (SB), the turning direction of the steering wheel (6) and the turning direction of the fuselage are matched ,
In addition, the steering tractor steering apparatus according to claim 1 , wherein the steering acceleration / deceleration mechanism (SA) and the forward / reverse switching mechanism (SB) are arranged in a steering gear box (58) .

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