JP3560912B2 - Tractor - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a tractor that can be replaced with a wheel type and a crawler type and has improved versatility that can be used over a wide range of paddy fields, upland farming, and dairy farming.
[0002]
[Prior art]
Tractors, particularly agricultural tractors, can be roughly classified into wheel-type (wheel-type) and crawler-type (crawler-type) by traveling equipment. Wheel-type is four-wheel drive type, rear-wheel drive type, front wheel with four wheels of two axes. The crawler type can be subdivided into a full crawler type and a semi-crawler type (see pages 257 to 259 of the new edition of Agricultural Machinery Handbook).
The wheel-type tractor can be used in a wide range of fields such as tilling, sowing, medium tilling, weeding, harvesting, and transporting by equipping a three-point link, a PTO shaft, and a hydraulic control device. It is a motor vehicle and is the mainstream of agricultural mechanization.
[0003]
In addition, full-crawler tractors have a smaller ground contact pressure than wheel-type tractors due to their large ground contact area, and can be run on uneven terrain such as soft terrain. For example, it is a so-called season-fixed type dedicated machine exclusively used for land improvement and land improvement by a subsoiler or the like for securing drainage in wet fields and the like where a wheel-type tractor cannot work.
On the other hand, a semi-crawler type tractor is an auxiliary device of a wheel type tractor in which a crawler belt unit is mounted in place of a rear wheel, and has a performance intermediate between a wheel type and a full crawler type on a soft ground.
[0004]
[Problems to be solved by the invention]
Wheel-type tractors are highly mobile and suitable for a wide range of work. If the field is not dried during a certain period of spring), it becomes practically impossible for the wheel-shaped tractor to enter the field, and there is a problem that tilling cannot be performed.
On the other hand, full-crawler tractors are effective in the above-mentioned situations, that is, under adverse conditions and in strong wetlands in various places, but lack mobility and are specialized machines, so they are limited to limited work. It is not applicable, and if it is used for harvesting work in dry fields etc., it will excessively ruin the field, and ultimately it will be necessary to prepare both wheel type tractors and full crawler type tractors, which will require investment in agricultural management. There is a problem that it will be huge.
[0005]
For these reasons, semi-crawler type tractors are proposed in, for example, Japanese Patent Application Laid-Open No. Hei 4-25778 (conventional example 1), Japanese Utility Model Publication No. 6-5974 and Japanese Utility Model Application Laid-Open No. 63-70488 (conventional example 2). Have been.
However, in the first conventional example, a rolling wheel is provided behind the rear wheel, and a crawler belt (endless revolving body) is mounted on both wheels, and a traveling device (rolling wheel) is provided behind the tractor body. Because it protrudes greatly, it interferes with the mounting of the work equipment using the three-point link.In addition, the wheelbase becomes excessively large and the turning performance is inferior. In this case, there is a problem that not only the working posture is lost and the driver is easily tired, but also the relative posture with respect to the tractor body of the working machine is lost, so that it is difficult to expect a stable working posture and an improvement in finishing accuracy.
[0006]
In the second conventional example, since the semi-crawler is swingably mounted, it is applied to a dedicated machine such as a combine or a harvester, although it has a certain degree of adaptability in work in uneven terrain. Therefore, there is a problem that it is difficult to adopt the tractor which requires mobility and versatility.
Further, there is a problem that the endless running body of the semi-crawler is easily detached from the starting rotating body or the like, that is, the so-called detachment is easy.
Accordingly, the present invention provides a tractor in which the semi-crawler swings the semi-crawler so that the pitching is small, the mobility and running performance are excellent, and the front wheel is prevented from floating.
[0007]
[Means for Solving the Problems]
The present invention has left and right front wheels steerable by operating a steering wheel, and has a left and right semi-crawler on left and right rear axles driven by a transmission and a rear wheel differential device incorporated in a tractor body. The semi-crawler A rotary drive, a front and rear rotary follower that is mounted around a front end and a rear end of the track frame below the rotary drive, and a guide wheel disposed between the front and rear rotary followers; An endless revolving body that is mounted in tension over the rotary driver and the front and rear rotary followers is configured in a tapered shape in a side view, and the rotary driver has a center attached to a rear axle. An oscillating support shaft is provided below the rear axle to support the track frame so that it can freely swing up and down, and is supported on a tractor body. The front grounding length is determined based on a vertical line passing through the axis of the oscillating support shaft. And a rear contact length is small, and a front rotating follower is disposed near a step of getting on and off the tractor body so that a front part of the endless revolving vehicle is a step for getting on and off. Truck between body A swing limiter for limiting the vertical swing range of the frame is provided, and the swing limiter lowers the vertical swing range of the front rotating follower with respect to when the contact portion of the endless revolving body is horizontal. Upper swing is set to be larger than swing By doing so, the above-mentioned problem was solved.
[0008]
That is, when the tillage is ahead of the wheel type due to irregular weather in the autumn and the influence of snow in the early spring, etc., a tractor having left and right semi-crawlers enables so-called spring plowing. Since the tractor can swing, the pitching phenomenon of the tractor is small, so that the fatigue of the operator (driver) is not excessive, the working posture is stable, and the working accuracy can be secured.
In addition, since it is a semi-crawler, the contact pressure is lower than that of the rear wheel, and not only the traction force can be increased, but also the work along the contour line can be performed with less side slip even when working on a slope.
[0009]
Further, for example, due to irregular weather in autumn, it is possible to form a drainage ditch in a field by using, for example, a subsoiler or the like by using a semi-crawler type.
Further, when rocking property is required, such as in a pest control operation or a harvest operation in a dry field or the like, the operation can be performed by a semi-crawler type tractor.
Further, since the swing range of the semi-crawler is limited, it is possible to prevent the left and right front wheels from rising while running on snowy roads, super wetlands, uneven terrain, etc. with the left and right semi-crawlers. It is.
[0010]
Further, the swing limiting means may have the same vertical swing range as the reference when the contact portion of the endless revolving body hung on the front and rear rotating follower is on a horizontal plane, or swing upward from the downward swing. Is preferably set large, and the swing limiting means includes a box-shaped bracket attached to a track frame and having a vertical guide portion, and a rolling bracket inserted into the guide portion and And a fixing bracket having a roller to be mounted and attached to the tractor vehicle body.
Further, in order to adjust the tension and relaxation of the endless revolving body mounted on the rotary driving body and the front rotation follower accompanying the swing of the track frame, the front rotation follower is provided with a tension adjusting means. Therefore, in both cases of forward and backward traveling with the left and right semi-crawler, there is no derailing, side running, etc. of the endless revolving body, it can be reliably circulated and can exert a large traction force, and during circulating Endless runners have less undulation.
[0011]
Also, there are left and right front attachments attached to the left and right vertical surfaces of the tractor body and made detachable, and left and right rear attachments attached to the lower surface of a rear axle case protruding from the tractor body and made detachable. Since the track frame of the semi-crawler is swingably mounted on the tractor body via the mounting frame which is framed in a rectangular shape in a plan view, the burden on the tractor body can be increased even when the left and right semi-crawlers are mounted on the tractor body. And installation is easy and quick.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
In FIG. 1 showing an entire side view of a tractor provided with a semi-crawler, FIG. 2 showing a rear view, and FIG. 3 showing a configuration of a traveling transmission system, a tractor 1 according to the present invention can be steered by operating a steering handle 2. Left and right front wheels 3 are provided, and right and left driven by a rear wheel drive transmission system 7 having a transmission 5 and a rear wheel differential 6 that are capable of changing the running speed incorporated in the tractor body 4 to a plurality of speeds. The rear axle 8 is provided with left and right semi crawlers 10.
[0013]
The left and right semi-crawlers 10 include a rotary driving body 11 attached to a shaft end of a rear axle 8, front and rear rotation followers 13 and 14 mounted on a track frame 12, and a front and rear rotation of the rotary driving body 11. The track frame 12 is supported by the tractor vehicle body 4 so as to be vertically swingable via a swing support shaft 16.
A driver's seat 17 is provided behind the steering wheel 2 to constitute a steering device 18. The steering device 18 is surrounded by a cabin 19, and the cabin 19 is mounted on the tractor body 4.
[0014]
The cabin 19 includes a skeleton 20 framed in a box shape, a windshield element 21 mounted on the front of the skeleton 20, a rear glass element 22 mounted on a rear surface of the skeleton 20, and a driver seat 17. Side glass elements 23 attached to the skeleton body 20 on both left and right sides of the vehicle, and left and right opening and closing doors 25 which are opened and closed about a vertical axis by hinge means 24 in front of the side glass elements 23. Together with step 30, it constitutes a part of means for getting on and off the control device 18. The tractor body 4 is mainly composed of an engine 26 and a transmission case 27 connected to the rear surface of the engine 26. The engine 26 is covered with a bonnet 28, and the transmission case 27 has a main clutch element 29. The driving power transmission system 7 for receiving engine power via the main clutch element 29, a PTO transmission system not shown, and the like are built in.
[0015]
The traveling transmission 5 includes a main transmission 31 that can shift the traveling speed to a plurality of speeds, an auxiliary transmission 33 that can shift the traveling speed up and down by a lever 32, a shuttle transmission (not shown), a creep transmission, and the like. And is linked to the rear wheel differential device 6 via a differential drive shaft 34 exemplified by a bevel pinion shaft.
The left and right output shafts 6A of the rear wheel differential device 6 are linked to the left and right rear axles 8 via a brake device 35 and a speed reduction device 36. The rear axles 8 are connected to a rear axle case 37 as shown in FIG. The right and left rear axle cases 37 support the left and right rear wheel fenders 38 and the rear part of the cabin 19.
[0016]
As shown in FIGS. 4 to 7, the semi-crawler 10 is mounted on the tractor vehicle body 4 via a mounting frame 39 which is mounted on the lower surface of the tractor vehicle body 4 and is framed in a rectangular shape in plan view.
The mounting frame 39 is attached to the left and right vertical surfaces of the tractor vehicle body 4 and is detachably attached by bolts or the like, and is attached to the lower surface of the rear axle case 37 protruding from the tractor vehicle body 4 and bolts. The left and right rear attachments 41 are detachable by means of the like, and the attachment frame 39 is fixed to the lower abdomen of the tractor body 4 via bolts and the like via the front and rear attachments 40, 41.
[0017]
Thus, the semi-crawler 10 is not directly supported on the tractor body 4 but is supported via the mounting frame 39 because the transmission case 27 and the like constituting the tractor body 4 are usually made of casting, Since there is a possibility of cracks or the like due to repeated external force or the like, the support is made via a mounting frame 39 made of a steel rectangular frame.
The rear mounting member 41 of the mounting frame 39 is provided with a swing support shaft 16 protruding in the left-right direction. On the other hand, the track frame 12 is configured such that the left and right swing support shafts 16 can be rotated around its axis. A receiving bearing cylinder 42 is provided, and the track frame 12 of the semi-crawler 10 is swingably mounted on the tractor body 4 via the mounting frame 39 by the swing support shaft 16 and the bearing cylinder 42.
[0018]
Since the semi-crawler 10 may be supported on the tractor body 4 so as to be swingable, the semi-crawler 10 may be provided with the swing support shaft 16 on the track frame 12 and the bearing cylinder 42 on the tractor body 4 side.
Further, the position of the swing support shaft 16 is free as long as its axis is parallel to the rear axle 8, but in the present embodiment, as shown in FIG. The swing support shaft 16 is located below the V. In this way, the swing amplitude when running through an uneven field or the like is reduced by the swing support shaft 16 being closer to the ground contact side, and the pitching phenomenon occurs. It can be suppressed effectively, which is advantageous.
[0019]
The rotary driving body 11 in the semi-crawler 10 can be selected from a drum type, a roller type, a sprocket type and the like, but is a sprocket type in the example shown in the drawing, and a plurality of bolts are attached to the shaft end flange 8A of the rear axle 8 as shown in FIG. And so on.
The rotation driving body 11 is integrally provided with a support shaft 43 protruding outward at the axis thereof, and a bearing portion 44A of a support arm 44 is externally fitted to an outer end of the support shaft 43. Are supported by a bracket 45 projecting from the track frame 12 via another swing support shaft 47.
[0020]
The other swing support shaft 47 extends on the axis of the swing support shaft 16 described above, and the track frame 12 has a swing shaft having two common shaft centers at the inside and outside of the rotary drive body 11. By being supported by the support shafts 16 and 47, lateral runout and the like are reliably prevented.
The support arm 44 is provided with a lock means 48 for supporting the rotary driving body 11 and locking relative swing with respect to the track frame 12. The lock means 48 has a lock hole 48A formed in the support arm 44 and a lock hole 48A. And a lock pin 48C that is inserted into and removed from the receiving hole 48B formed in the bracket 45 and the holes 48A and 48B when the holes 48A and 48B coincide with each other, and is formed below the swing support shaft 47 in the illustrated example. And a plurality of lock holes 48A and 48B may be formed to insert and remove a plurality of lock pins 48C. The lock pins may be bolts and nuts. You can also.
[0021]
Therefore, when the semi-crawler 10 is replaced with the rear axle 8, the swing is restricted by the locking means 48 to form a fixed form, the rotary driving body 11 is attached to the rear axle 8, and the positioning of the swing support shaft 16 is performed. After the semi-crawler 10 is changed, the locking means 48 is unlocked to be able to swing.
In FIG. 10, reference numeral 49 denotes a retaining collar, which is fitted to the bearing portion 44 </ b> A and fixed to the shaft end surface of the support shaft 43 by a bolt 50. Although the bearing 44A is shown as a ball bearing, other bearings such as a pillow block bearing may be used.
[0022]
The right and left semi-crawlers 10 have a so-called conical shape in a side view as shown in FIGS. 1 and 8, and the front and rear contact lengths L1 and L2 are different based on a vertical line VV passing through the axis of the rear axle 8. In the drawing, the front contact length L1 is large and the rear contact length L2 is small, and the semi-crawler 10 is provided at a rear portion of the tractor body 4 in order to prevent the semi-crawler 10 from protruding greatly rearward from the tractor body 4. The work equipment (rotary, plow, subsoiler, broadcaster, etc.) can be easily mounted through mounting means such as three-point links, and a sufficient grounding length is secured to prevent skidding on slopes. Promising great traction.
[0023]
The endless revolving body 15 in the left and right semi-crawlers 10 is an elastic crawler (rubber crawler) having a row of grounding lugs 15A on the outer circumference and a row of guide projections 15B on the inner circumference. The front rotation follower 13 is positioned in the vicinity of the getting on / off step 30 so as to be inclined forward and downward between the front rotation follower 11 and the front rotation follower 13.
By adopting such a configuration, the endless running body 15 can be used as a step-in / out assist step, and the endless running body 15 becomes an obstacle even when the door 25 is opened and closed around the hinge means 24. Also, the distance between the axles (the distance between the front wheel 3 and the rear wheel 9) is almost the same as that of the semi-crawler type tractor 1 or the wheel-type tractor. It is possible.
[0024]
As shown in FIG. 1, the tractor 1 moves forward when the rotary driving body 11 is driven to rotate in the direction of arrow F, and the tractor 1 moves backward when driven to rotate in the direction opposite to the arrow F. The endless revolving body 15 in which the rotation driving body 11 which is on the slack side during traveling is mounted on the front rotation follower 13 is adjusted by the front rotation follower 13 in order to adjust the tension and relaxation accompanying the swing of the track frame 12. Is provided with a tension adjusting means 51.
As shown in FIG. 8, the tension adjusting means 51 automatically adjusts the tension of the support fork 52 of the front rotation follower 13 with a coil spring 53 and a tension cylinder 54, and is provided in the track frame 12. .
[0025]
A plurality of, in the figure, four guide wheels 55 are arranged in a row on the track frame 12, and the inner peripheral surface of the endless revolving running body 15 in which the rotary drive body 11 is mounted on the front rotary follower 13. A guide means (crawler support) 56 is provided for contact with and preventing slack.
The guide means 56 is provided detachably on the tension cylinder 54. As shown in FIG. 7, the guide part 56A at the tip is branched into two parts, and is made of an elastic strip such as SS330. Have been.
[0026]
The left and right semi-crawlers 10 absorb the pitching phenomenon of the tractor body 4 on uneven terrain, irregular terrain, snowy roads and the like by the track frame 12 swinging up and down around the swinging support shaft 16 as a fulcrum. Although the vehicle runs, a swing limiter 57 for limiting the vertical swing range of the track frame 12 is provided.
As shown in FIG. 4, FIG. 7, and FIG. 9, the swing restricting means 57 includes a box-shaped bracket 58 attached to the track frame 12 and having a vertical guide portion 58A, and inserted into the guide portion 58A. And a fixed bracket 59 that has a roller 59A that is rolling and that is mounted on the tractor vehicle body 4 via a mounting frame 39. The fixed bracket 59 is fixed to the mounting frame 39. It is detachably attached to the receiving bracket 59A by bolts.
[0027]
Further, the swing limiter 57 is configured such that the vertical swing range is the same as when the ground contact portion of the endless revolving body 15 mounted on the front and rear rotary followers 13 and 14 is on a horizontal plane, or the vertical swing range is lower. The upward swing is set large, and in the illustrated example, the front side is inclined by 8 ° upward and 5 ° downward.
Note that the swing limiting means 57 may have a box-shaped bracket 58 provided on the mounting frame 39 and a fixed bracket 59 provided on the track frame 12, or may have a sliding shroud instead of the roller 59A. good.
[0028]
Referring to FIG. 3, a front wheel traveling transmission system 60 is branched from a rear wheel differential drive shaft 34, and the left and right front wheels 3 can be driven via a front wheel differential device 61 provided in the transmission system 60.
The front wheel drive transmission system 60 has a shift gear 62 provided on the rear wheel differential drive shaft 34, and can be selectively engaged with a gear 63 </ b> A on the first transmission shaft 63.
A second transmission shaft 64 having gears 64 </ b> A and 64 </ b> B is mounted on an extension of the first transmission shaft 63. Between the first and second transmission shafts 63 and 64, the front wheel 3 is in a driven state and a non-driven state. A clutch means 65 for switching to a driving state is provided, and when the vehicle travels straight ahead by changing to the semi-crawler 10, the clutch means 65 is disengaged and the front wheel 3 is in a non-driving state (so-called rear wheel driving, and the front wheel idles). When turning, the vehicle is provided with manual operation means for bringing the front wheel 3 into a driving state (four-wheel driving state) by bringing the clutch means 65 into contact.
[0029]
This artificial operation means is provided near the driver's seat, and is a shift operation lever when the clutch means 65 is the illustrated shift gear, and is a shift operation lever when the clutch means 65 is a hydraulic clutch. When the clutch means 65 is a hydraulic clutch, it is an operation lever of an electromagnetic control valve for controlling the on / off of the clutch.
In the front wheel traveling transmission system 60, a traveling power transmission between the second transmission shaft 64 and the front wheel differential drive shaft 61A for substantially equalizing the peripheral speed of the rotary driver 11 and the peripheral speed of the front wheel 3 in the semi-crawler 10 is substantially equal. 66 are provided.
[0030]
That is, when the left and right rear wheels 9 are replaced with the right and left semi-crawlers 10, the diameter of the rotary driving body 11 becomes approximately half the diameter of the rear wheels 9, and if the rear wheel traveling transmission system 7 is used as it is, The peripheral speed of the driver 11 is almost half (substantially half) that of the rear wheel 9, and when the front wheel 3 is driven in this state, the front wheel 3 is worn out early.
Therefore, when the rear wheel 9 is replaced with the semi-crawler 10 by using the rear wheel traveling system 7 as it is, the clutch means 65 provided in the front wheel traveling system 60 is disengaged, and the front wheel 3 is brought into a non-driving state (free running). Alternatively, the peripheral speed between the rotary driving body 11 and the front wheel 3 is made substantially equal by incorporating the traveling transmission body 66.
[0031]
In the embodiment shown in FIG. 3, a first hydraulic clutch 67 and a second hydraulic clutch 68 are provided side by side on the front wheel differential drive shaft 61 </ b> A or coaxially therewith, and a gear 67 </ b> A of the first hydraulic clutch 67 is provided. Is engaged with the first gear 64A on the second transmission shaft 64, and the gear 68A of the second hydraulic clutch 68 is engaged with the second gear 64B on the second transmission shaft 64. At this time, the gear ratio of the gears 64A and 67A Is set to a speed reduction ratio for making the peripheral speed between the rotary driving body 11 of the semi-crawler and the front wheel 3 substantially equal, and the gear ratio of the gears 64B and 68A is such that the rear wheel 9 and the front wheel 3 are at the same speed or the front wheel 3 Gear ratio.
[0032]
Therefore, when changing to the semi-crawler 10, the first hydraulic clutch 67 of the reduction gears 64A, 67A is engaged to drive the semi-crawler and the front wheels substantially at the same speed.
Since the front wheels 3 are not driven by disengaging both the first and second hydraulic clutches 67 and 68, the clutches 67 and 68 also serve as clutch means for switching between four-wheel drive and rear-wheel drive. .
FIGS. 11 to 13 show a second embodiment of a traveling transmission body 66 for making the peripheral speed of the semi-crawler 10 and the front wheel 3 substantially constant, and a hydraulic pressure is applied to the transmission shaft 64 and the differential drive shaft 61A of the front wheel traveling transmission system 60. A DT clutch (four-wheel drive on / off clutch) 69 and a hydraulic double-speed clutch (the front wheel rotates at about 1.6 times the speed of the rear wheel) 70 are provided side by side in front and rear. A double-speed shaft 71 having gears 71A and 71B meshing with a gear 70A rotatable on a transmission shaft 64 and a gear 61B fixed to a differential drive shaft 61A is detachably attached to the lower abdomen of the tractor body 4 under the clutch. A transmission shaft 66 </ b> A for the traveling transmission body 66 is mounted on the cassette case 72 so as to be coaxial with the double speed shaft 71.
[0033]
Further, an input gear 64A for the traveling transmission body 66 is provided on the transmission shaft 64, and a gear 66B that meshes with the input gear 64A is provided on the transmission shaft 66A. The transmission shaft 66A and the double-speed shaft 71 The clutch can be freely turned on and off by a clutch means 66C shown by.
In the second embodiment, when the rear wheel 9 is replaced with the semi-crawler 10, the clutch means 66C is engaged (connected), and the gears 64A and 66B, the double speed shaft 71, and the gears 71B and 61B are passed. The power is transmitted to the front wheel differential drive shaft 61A, and the speed is reduced by the traveling power transmission 66 of the front wheel traveling power transmission system 60 so that the peripheral speed of the rotary driving body 11 and the front wheel 3 become substantially the same.
[0034]
In the second embodiment, when the rear wheel 9 is mounted on the rear axle 8, the operation is performed as shown in FIG.
That is, when the turning angle of the front wheel 3 becomes about 34 ° or more by operating the steering handle, the turning angle detection switch 73 attached to the left front wheel case support is turned ON, and the DT / double speed solenoid valve 74 operates to the double speed side. The double speed clutch 70 is switched to "ON". This causes the front wheels to rotate at about 1.6 times the speed of the rear wheels.
The DT / double speed switch 75 is a switch for switching the type of power transmission to the front wheels, and can perform three-stage switching of “DT (4WD = four-wheel drive) / OFF”, “DT / ON”, and “double speed”. To activate the double speed turn, set this switch to the "double speed" position. When set to "DT.ON" or "OFF", the solenoid valve operates the DT hydraulic clutch 69 integrated with the double-speed hydraulic clutch 70 to switch on / off of the four-wheel drive.
[0035]
FIGS. 14 and 15 show a third embodiment of the traveling transmission body 66, in which front wheel differential drive shafts (or front wheel propulsion shafts interlocked therewith) may be configured as first and second shafts 76 and 77, and first and second shafts 76 and 77. A shift gear 78 for connecting and disconnecting the shafts 76 and 77 is slidably provided on the first shaft 76 by a spline or the like, and a transmission shaft 80 having gears 80A and 80B engaged with the gears 78 and 79 on the first and second shafts 76 and 77. When the semi-crawler 10 is changed with respect to the rear wheel 9, the shift gear 78 is cut off, and the front wheel differential 61 is decelerated via the gears 78, 80A, 80B, and 79. In this case, the peripheral speed between the rotary driving body 11 of the semi-crawler 10 and the front wheel 3 is made substantially constant. When the rear wheel 9 is mounted, the first and second shafts 76 and 77 are directly connected by the shift gear 78. .
[0036]
In the third embodiment, the double-speed turn shown in FIG. 12 and the like can be provided as shown in FIG.
FIG. 16 shows a fourth embodiment of the traveling power transmission 66, in which the rotary driving body 11 of the semi-crawler 10 is provided in the rear wheel traveling power transmission system 7 so as to be capable of switching to a speed increasing operation.
In FIG. 16, the left and right rear axles 8 are divided into first shafts 82 and 83, and both shafts 82 and 83 can be joined and separated via a first hydraulic clutch 84 connected and disconnected by a valve 84A. A second hydraulic clutch 86, which is connected and disconnected by a valve 86A, is mounted on the speed increasing sub shaft 85, and gears 85A, 85B which mesh with the gears 82A, 83A of the first and second shafts 82, 83 are provided in the sub groove 85. ing.
[0037]
In the fourth embodiment, the first hydraulic clutch 84 is disengaged and the second hydraulic clutch 86 is engaged, so that the left and right rear axles via the gears 82A, 85A, 85B, 83A, that is, the second shaft The peripheral speed between the rotary driving body 11 and the front wheels 3 is made substantially constant by increasing the speed of the 83. On the other hand, when the rear wheels 9 are mounted, the second hydraulic clutch 86 is disconnected and the first hydraulic clutch 86 is disconnected. The first and second shafts 82 and 83 are directly connected with the hydraulic clutch 84 in contact.
It is desirable that the traveling transmission body 66 of the fourth embodiment be detachably mounted on either the upper or lower part of the rear axle case 37.
[0038]
Further, in FIGS. 3 and 11 to 16, as shown in FIG. 13, a detection switch (detection device) 73 for detecting the steering angle of the left and right front wheels 3 and the left and right semi-crawlers 10 are simultaneously and independently controlled. For example, when the switch 73 detects that the steering angle of the front wheel 3 has been operated to a predetermined angle or more, the brake device 35 of the semi-crawler 10 inside the turning can be independently controlled by the switch 73 when the switch 73 detects that the steering angle of the front wheel 3 has been operated to a predetermined angle or more. By providing a controller (control device) 87 for braking, even a semi-crawler tractor improves the small turning performance, and it is desirable to switch the left and right front wheels 3 to speed-up driving during this turning. .
[0039]
That is, the tractor according to the present invention has left and right front wheels that can be steered by operating a steering wheel and can be driven by a front wheel traveling power transmission system, and has a transmission device and a rear wheel differential device built in the tractor body. Left and right rear axles driven by the wheel traveling transmission system are provided with left and right semi-crawlers, and a traveling transmission body for making the peripheral speed of the rotary driving body and the peripheral speed of the front wheels in the semi-crawlers substantially equal. In the case where the traveling transmission is a reduction gear that is provided in a front-wheel traveling transmission system and is capable of switching the rotational drive of the front wheels to deceleration, the traveling transmission is provided in a rear-wheel traveling transmission system and includes a semi-crawler. It is assumed that the speed reducer is capable of switching the rotational drive of the rotary drive to a speed increase.
[0040]
Further, the front wheel traveling power transmission system is provided with clutch means for switching the front wheels between a driving state and a non-driving state, and when traveling straight ahead with a semi-crawler, disengaging the clutch means to put the front wheels into a non-driving state, and It is provided with a manual operation means of a clutch means for bringing the front wheel into a driving state by bringing the clutch means into contact, and a steering angle detecting device for detecting a steering angle of the left and right front wheels and a left and right semi-crawler are independently provided. A control device that brakes the brake device of the semi-crawler inside the turn when the steering angle detection device detects that the steering angle of the front wheel has been operated to a predetermined angle or more. It is desirable that the left and right front wheels be switched to speed-up drive when making this turn, and that the traveling transmission is desirably incorporated in a detachable manner.
[0041]
【The invention's effect】
As described in detail above, in the tractor of the present invention, since the left and right semi-crawlers are supported so that their track frames are not fixed to the tractor body but swingably, the semi-crawler type tractor during running may cause a pitching phenomenon. The contact pressure is low, the contact pressure is low, and the stability of the working posture and the finishing accuracy can be improved while improving the wetland performance.
In addition, since the swing range of the semi-crawler is limited, it is possible to reliably prevent the front wheels from rising and the like while running on snowy roads, sloping terrain, irregular terrain, and the like, thereby enabling stable running.
[Brief description of the drawings]
FIG. 1 is a side view of a semi-crawler type tractor.
FIG. 2 is a rear view of the semi-crawler type tractor.
FIG. 3 is an overall configuration diagram of a traveling transmission system.
FIG. 4 is an exploded perspective view of left and right semi crawlers.
FIG. 5 is a plan view of left and right semi crawlers.
FIG. 6 is an elevational view taken along arrow AA of FIG. 5;
FIG. 7 is an elevation view taken along the line BB of FIG. 5;
FIG. 8 is a side view of a semi-crawler.
FIG. 9 is a perspective view of the swing regulating means.
FIG. 10 is an enlarged sectional view of a swing support shaft.
FIG. 11 is an overall configuration diagram showing a second embodiment of the traveling transmission system.
FIG. 12 is a partially enlarged view of FIG. 11;
FIG. 13 is a configuration diagram showing switching of DT / double-speed turn and the like.
FIG. 14 is an overall configuration diagram showing a third embodiment of the traveling transmission system.
FIG. 15 is a partially enlarged view of FIG. 14;
FIG. 16 is a rear view showing the configuration of a fourth embodiment of the traveling power transmission system.
[Explanation of symbols]
1 tractor
2 Steering handle
3 front wheels
4 Tractor body
8 Rear axle
9 Rear wheel
10 semi crawlers
11 Rotary drive
12 track frame
13 Front rotation follower
14 Rear rotating follower
15 Endless runner
16 swing support shaft

Claims (4)

Left and right rear axles (8 ) are provided with left and right front wheels (3) steerable by operation of a steering wheel, and driven by a transmission (5) and a rear wheel differential (6) incorporated in a tractor body (4). ) Includes left and right semi crawlers (10 ) , the left and right semi crawlers (10) being a rotary driver (11), and a front end and a rear end of a track frame (12) below the rotary driver (11). The front and rear rotation followers (13) and (14), which are mounted on the front and rear, the guide wheel (55) arranged between the front and rear rotation followers (13) and (14), and the rotation driver (11). And an endless revolving body (15) mounted in tension over the front and rear rotational followers (13) and (14), and configured in a tapered shape in a side view. Its center is attached to the rear axle (8), and this rear axle (8) A swing support shaft (16) that supports the tractor body (4) so as to freely swing the track frame (12) in the vertical direction is disposed below, and a vertical line passing through the axis of the swing support shaft (16). The front contacting length is large and the rear contacting length is small on the basis of the reference, and the front rotating follower (13) is provided with a tractor body (4) so that the front part of the endless revolving vehicle (15) can be used as an alighting assist step And a swing limiting means (57) for limiting the vertical swing range of the track frame (12) is provided between the track frame (12) and the tractor body (4). The vertical swing range of the front rotation follower (13) is greater than the downward swing with respect to when the ground contact portion of the endless revolving body (15) is horizontal above by the swing limiting means (57). A tractor characterized by being set large . The swing limiting means (57) is attached to the track frame (12) and has a box-shaped bracket (58) having a vertical guide (58A), and is inserted into the guide (58A); The tractor according to claim 1, characterized in that it comprises a fixing bracket (59) having a rolling roller (59A) and attached to a tractor body (4) . In order to adjust the tension and relaxation of the endless revolving body (15) mounted on the rotary driving body (11) and the front rotation follower (13) due to the swing of the track frame (12), the front rotation follower is adjusted. tractor according to claim 1, wherein the body tensioning means (13) (51) is found with. Left and right front attachments (40) attached to the left and right vertical surfaces of the tractor body (4) and detachable, and attached and detached to the lower surface of a rear axle case (57) protruding from the tractor body (4). The track frame (12) of the semi-crawler (10) is swingable via a mounting frame (39) framed in a rectangular shape in plan view having a left and right rear mounting tool (41) that can be freely swung. The tractor according to claim 1, wherein the tractor is mounted on a tractor.

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