JP3828528B2 - Agricultural tractor - Google Patents

Description

  The present invention relates to an agricultural tractor.

2. Description of the Related Art Conventionally, there is an agricultural tractor in which the body is turned by changing the driving speed of a continuously variable transmission that is interlocked and connected to the left and right traveling units (see, for example, Patent Document 1).
Japanese Patent Laid-Open No. 7-81608

  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.

Therefore, in the present invention, the traveling transmission is linked to the engine, the drive shafts of the left and right traveling units are linked to the traveling transmission, and the drive shafts are mutually rotated in the same rotational direction by the traveling transmission. The steering gear is linked to the engine and the drive shafts of the left and right traveling parts are linked to the steering gear. The drive shafts are reversed by the steering gear. Drive in the direction of rotation, increase or decrease the rotational speed of each drive shaft with both transmissions to enable the vehicle to turn up and down, and connect the steering wheel to the steering transmission while moving the forward / reverse shift lever for traveling In an agricultural tractor linked to a transmission , a front mission and a rear mission are arranged on the fuselage, and the steering transmission is attached to the front mission, while a traveling transmission is attached to the rear mission. of Together interlockingly connected a line for transmission and steering transmission for the first follower shaft, a front transmission and the rear transmission and operatively connected with the second interlocking shaft.

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

That is, the driving transmission is linked to the engine and the drive shafts of the left and right traveling parts are linked to the driving transmission so that the drive shafts are driven in the same rotational direction by the driving transmission. The steering gearbox is linked to the engine, the drive shafts of the left and right traveling parts are linked to the steering gearbox, and the drive shafts are driven in opposite directions by the steering gearbox. by, and pivotable up decelerate the aircraft by increasing or decreasing the rotational speed of the drive shafts by both the transmission, the scan tearing wheel while interlocked to steer for transmission, the forward-reverse shift lever traveling transmission In an agriculturally connected tractor , a front mission and a rear mission are arranged on the fuselage, and the steering transmission is attached to the front mission, while a traveling transmission is attached to the rear mission. With transmission Together interlockingly connected the direction for transmission in a first interlocking shaft, a front transmission and the rear transmission to have operatively connected with the second interlocking shaft, the direction of rotation of the left and right traveling unit by traveling transmission, e.g. In a state where the vehicle is traveling forward by forward rotation, the rotation direction of the left traveling unit is driven to rotate forward, for example, by the steering transmission, and the rotational direction of the right traveling unit is driven to rotate backward. The left traveling part is driven to increase the speed by both transmissions, and the right traveling part is driven to decelerate by both transmissions, so that the airframe can be smoothly turned to the right.

  Thus, since the left and right traveling units can be complementarily increased and decreased by the two transmissions during the turning operation of the aircraft, the aircraft can smoothly turn from a slow turn to a sudden turn. Generation | occurrence | production of the malfunction of damaging a field by a right-and-left traveling part can be prevented.

  In addition, it is possible to control the turning of the aircraft with a single steering wheel, and it becomes easy to operate, and the problems caused by the unevenness and backlash of the left and right operation mechanisms 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.

  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 travel drive device DR according to the present invention, which is an upper front portion of an airframe frame 2 equipped with crawler-type left and right traveling units 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.

  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 driving 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 machine lifting mechanism.

  2 and 3 show the arrangement of the travel drive device DR. The engine 17, the front mission 18 and the rear mission 19 mounted on the prime mover 3 are arranged in this order from the front along the longitudinal center line of the aircraft. A hydrostatic stepless 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 is mounted on the front of the rear mission 19. A hydrostatic traveling continuously variable transmission 21 composed of a hydraulic motor and a constant capacity hydraulic motor is attached, and each part of the traveling drive device DR will be described in the order of power transmission.

  4 and 5 show a front mission 18, and FIG. 6 shows a rear mission 19. A front mission input shaft 23 linked to the engine 17 through a double hook joint 22 is connected to the steering through a gear train 25. Universally connected to the input shaft 20a of the continuously variable transmission 20 and a universal joint 26, 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. The power take-off speed changer 30 and the meshing reduction gear 30a are linked to the power take-off shaft 31.

  On the other hand, the output shaft 21b of the traveling continuously variable transmission 21 is linked to the rear transmission output shaft 34 via a traveling clutch 32 and a sub-transmission unit 33 capable of neutral and three-speed shifting. 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, 26 and the second interlocking shaft 35, and is connected to the front end of the front input shaft 36. Via the formed traveling meshing bevel gear 37, the intermediate shaft 39 that is pivotally supported between the left and right traveling unit drive shafts 38L and 38R is linked and connected.

  The left and right traveling unit drive shafts 38L and 38R are connected to the left and right traveling units 1L and 1R through 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. 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.

  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 and 40R of the left and right planetary gear mechanisms 40L and 40R, 49R is linked to the left and right steering gears 50L and 50R, 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. A differential lock mechanism 51 including 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.

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

  As shown in FIGS. 7 and 8, the steering device ST has a stay 54 protruding from the inner surface of the front side of the cabin 4, and is attached to a steering post 55 fixed to the rear end of the stay 54 in a tilted state of front, rear and rear. , A steering shaft 56 having a steering wheel 6 attached to the upper end thereof 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 and 26 and the extension shaft 57. It is linked to the operation input shaft 59 protruding from the upper surface of 5 8.

  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.

  As shown in FIGS. 9 to 11, the steering speed increasing / decreasing mechanism SA has a rack support shaft 60 installed in the left-right direction in the steering box 58, and a rack support 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 of the tilting body 63 is pivotably pivoted to the left and right, and the operating pin projects 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. 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 is connected to the connecting rod 69 and the steering shift lever. To the steering operation shaft 70 of the steering continuously variable transmission 20 through 70a. It is dynamic linking.

  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.

  Further, by providing a forward / reverse switching mechanism SB in the steering box 58 and reversing the rotational direction of the steering continuously variable transmission 20 in conjunction with the forward / backward tilting of the forward / reverse transmission lever 8 described later, The body is turned in the turning direction of the steering wheel 6 regardless of the advance.

  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 downward extending portion 80a of 80 and the tilting body 63 are linked and connected via a connecting rod 81, and a tilting operation lever 82 is connected to the projecting end 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.

  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 the 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 88b and the travel speed operation lever 89 are linked to the travel speed operation shaft 90 of the continuously variable transmission 21 for travel.

  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, with the cylinder side fixed to the body frame 2 and the screw side connected to the forward / reverse transmission plate 87. Is different.

  In addition, 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, A forward switch 93 and a reverse switch 94 are attached to the switch support plate 91, and when the forward / reverse shift lever 8 is operated to the forward side, the forward end of the forward / reverse shift plate 87 and the forward switch 93 come into contact with each other 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 and the reverse switch 94 come into contact with each other, and only the reverse switch 94 is turned on. Both switches 93 and 94 are turned OFF, and each switch 93 and 94 is connected to an electrohydraulic direction control valve 92 connected to the tilting hydraulic cylinder 83, and the detection output of each switch 93 and 94 Switch the oil passage of the electromagnetic hydraulic direction control valve 92 , And so as to stretch activated tilt hydraulic cylinder 83.

  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 unit 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 and 11R of the left and right traveling portions 1L and 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.

  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 traveling continuously variable transmission 21.

  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.

  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, 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. From the variable displacement hydraulic pump that was transmitted and neutral until then, the discharge amount was zero, and the steering continuously variable transmission 20 output at the rotation speed corresponding to the operation amount of the steering wheel 6, and the differential Left and right planetary gears via gear mechanism 48 Structure 4 0L, the left and right sun gears 49L of 40R, rotate the 49R.

  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.

  Note that 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 or backward travel. 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 a neutral state, that is, when the airframe 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 return seat mechanism 84 after being released. In this state, since the tilting body 63 is not tilted forward or backward, 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 is not turned.

  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 speed of the left and right drive wheels 11L and 11R is made the same, thereby improving the straightness of the agricultural tractor TR. be able to.

The whole side view of the agricultural tractor which comprises the traveling part drive device concerning the present invention. The schematic plan view which shows schematic structure of the said travel part drive device. The top view which shows the structure of the said travel part drive device. The partial cross section side view which shows the structure of a front mission. The partial cross section top view which shows the structure of a front mission. The partial cross section side view which shows the structure of a rear mission. The side view of a steering device. The front view of a steering device. Sectional side view of a steering gear box. A sectional front view of a steering gear box. The cross-sectional top view of a steering gear box.

Explanation of symbols

DR travel drive
SA Steering speed increase / decrease mechanism
SB Forward / reverse switching mechanism
SE Forward / reverse detection sensor
1L, 1R Left and right traveling part 6 Steering wheel 8 Forward / reverse speed change lever
20 Steering continuously variable transmission
21 Continuously variable transmission
58 Steering box

Claims (1)

A driving transmission is linked to the engine (17), and the driving shafts (38L) (38R) of the left and right traveling sections (1L) (1R) are linked to the driving transmission to connect each driving shaft (38L ) (38R) are driven in the same rotational direction by the traveling transmission, while the steering transmission is linked to the engine (17), and the left and right traveling parts (1L) (1R) are connected to the steering transmission. ), The drive shafts (38L) and (38R) are interlocked and connected to each other, and the drive shafts (38L) and (38R) are driven in the reverse rotation direction by the steering transmission. (38L) (38R) The number of rotations can be increased or decreased to enable the vehicle to turn and decelerate, and the steering wheel (6) is linked to the steering transmission while the forward / reverse transmission lever (8) is connected to the traveling transmission. Agricultural tractor linked to
A front mission (18) and a rear mission (19) are arranged on the airframe, and the steering transmission is attached to the front mission (18), while a traveling transmission is attached to the rear mission. with the use transmission and steering transmission for interlockingly connected with the first interlocking shaft (27), the front transmission (18) and re a mission (19) and that interlockingly connected with the second interlocking shaft (35) Agricultural tractor characterized by.

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