JP2002120773A - Arrangement construction of six-wheel work vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve a problem that conventionally a front wheel and a rear wheel are apt to slip during rotation of a six-wheel work vehicle, and a rotation radius becomes large because a slip amount of the front wheel is different from that of the rear wheel, and a desired track sometimes cannot be taken and thereby working efficiency deteriorates. SOLUTION: In this six-wheel working vehicle A, two hydrostatic continuously variable transmission mechanisms 74 are connected, and one of the two hydrostatic continuously variable transmission mechanism 74 is used for traveling, and the other is used for steering to drive and steer an axle. A tread La is shorter than a tread Lb between a first wheel 33 and a third wheel 35. A tread Lc between the first wheel 33 and a second wheel 34, and a tread Ld between the second wheel 34 and the third wheel 35 are shorter than the tread La.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for improving the steering operability of a six-wheel working vehicle.

[0002]

2. Description of the Related Art Conventionally, two HSTs are connected left and right, an axle is projected from each HST type transmission to both sides, and wheels are fixed to the ends of both axles. The technology of a vehicle in which the angle of the vehicle is changed to drive the left and right wheels is known. In this technology, when traveling straight ahead, the traveling speeds of the left and right HSTs are made equal,
When turning, the running speed of the left and right wheels is configured to be different.

[0003]

In general, the longer the wheelbase (wheel base), the better the riding comfort. However, if the wheelbase is too long, the turning radius becomes large and the rigidity of the vehicle body becomes disadvantageous. The wider the tread, the better in terms of stability and ride comfort, and the smaller the turning radius, but the wider the wheel tread, the wider the car body increases air resistance, causing disadvantages in car body rigidity, drivability, etc. . Therefore, it is preferable that the wheelbase of the front and rear wheels is shorter and the total length of the vehicle body is shorter when turning. During turning of the conventional vehicle described above, the front and rear wheels are likely to slip, and the slip amount is different between the front and rear wheels. Therefore, the conventional traveling vehicle as described above has a large turning radius and is as desired. Sometimes I couldn't keep track. For example, in the case of lawn mowing work around a tree or the like, it is necessary to travel the same position many times to perform the work, and the work efficiency has deteriorated.

[0004]

The problems to be solved by the present invention are as described above. Next, means for solving the problems will be described.

That is, as shown in claim 1, the front and rear three axles are provided with a pair of left and right first wheels, second wheels and third wheels, respectively, and a difference is provided between the rotation speeds of the right and left wheels, thereby to make the airframe. In a six-wheel working vehicle with a turning mechanism, the first wheel, the second wheel, and the third wheel each have a shorter wheelbase than the wheelbase of the first wheel and the third wheel, and the first wheel, the second wheel, and the third wheel. The wheelbase of the first and second wheels and the wheelbase of the second and third wheels are configured to be shorter than the wheelbase of the wheels.

According to a second aspect of the present invention, a pair of left and right first, second and third wheels are provided on the front and rear three axles, respectively.
Connect two hydrostatic stepless transmission mechanisms, one for traveling,
The other is a six-wheel working vehicle which drives and steers an axle for steering (steering). The first wheel, the second wheel, and the third wheel are respectively based on the distance between the first wheel and the third wheel. The distance is short, and the shaft distance between the first wheel, the second wheel, and the second wheel and the third wheel is shorter than the distance between the first wheel, the second wheel, and the third wheel.

BEST MODE FOR CARRYING OUT THE INVENTION

Next, an embodiment of the present invention will be described. In this embodiment, a riding type six-wheeled working vehicle A will be described as an example of the six-wheeled working vehicle A according to the present invention. FIG. 1 is an overall side view of a six-wheeled working vehicle A according to the present embodiment, FIG. 2 is a plan view showing a traveling unit, FIG. 3 is a side view showing a ground height position adjusting mechanism of a second wheel, and FIG. FIG. 4 is a rear cross-sectional view illustrating a ground height position adjusting mechanism of a second wheel. 5 is a side view showing the first and second belt transmission mechanisms, FIG. 6 is a side view showing the transmission section, FIG. 7 is a cross-sectional plan view of the transmission section showing the straight-line power transmission system, and FIG. FIG. 4 is a cross-sectional plan view of a transmission unit showing a system. 9 is a plan view showing an arrangement of wheels, FIGS. 10 and 11 are diagrams showing an example of a turning track of a six-wheeled working vehicle, and FIG. 12 is a view showing a turning track of a six-wheeled working vehicle according to the present invention. .

A shown in FIG. 1 is a work vehicle according to the present invention. The work vehicle A has a traveling section 2.
2 and a driving unit 3 at the front of the vehicle body frame 1, and a motor unit 4 and a transmission unit 5 at the rear.
Are arranged one above the other, and the prime mover unit 4 and the traveling units 2 are connected and linked via the transmission unit 5.

As shown in FIGS. 1 and 2, the body frame 1 has a pair of left and right front and rear portions extending in the left and right direction between a pair of front and rear portions of a pair of left and right front and rear extension frame forming pieces 10 and 10 extending in the front and rear direction. The direction-stretched frame forming pieces 11 are laid horizontally to form a well shape.

Then, the lower end portions of a pair of left and right front frames 12, 12 are attached to the front wall of the longitudinally extending frame forming piece 11, and the two front frames 12, 12 are raised toward the front upper side. A horizontal frame 13 extending in the left-right direction is suspended between the upper ends of the horizontal frame 12, and a pair of left and right seat pivot brackets 14 project upward from a central portion of the horizontal frame 13. The lower ends of the pair of left and right rear frames 15 and 15 are fixed to the left and right extending frame forming pieces 11 by penetrating the lower ends of the pair of right and left rear frames 15 and 15 in the front-rear direction. Between them, a guard frame 16 formed in a rectangular frame shape in a plan view is suspended.

A mounting table 17 projects from the center of the front wall of the front-side left-right extending frame forming piece 11 so as to project forward, and a battery 18 and a fuel tank 19 are mounted on the mounting table 17. At the same time, a front support 20 for supporting the front end of the transmission portion 5 is erected at the center of the rear side of the left-right extending frame forming piece 11, and a pair of left and right front-rear supports 2 is provided.
1.21 are erected. A pair of right and left motor part columns 22 and 22 for supporting the motor part 4 are erected at the center of the left-right extending frame forming piece 11.

A PTO shaft case 23 extending in the left-right direction is horizontally mounted in the middle of the pair of left and right rear frames 15, and a PTO shaft 24 is rotatably inserted into the PTO shaft case 23. The front end of the lifting link 25 is pivotally supported on the outer peripheral surface of the central portion of the PTO shaft case 23 so that the lifting link 25 can be turned up and down around the axis of the PTO shaft 24,
The middle part of the lifting link 25 and the guard frame 16
A lift cylinder 26 is interposed between the rear horizontal frame forming piece 16c and the center of the piece, and a hitch body 27 for connecting various working machines is provided at the rear end of the lift link 25. Attached.

In the running section 2, first and second extending portions in the left-right direction between the front end portion, the center portion, and the rear end portion of the pair of left and right longitudinally extending frame forming pieces 10, 10 described above.・ The third wheel spindles 30, 31 and 32 are laid horizontally, and the first, second and third wheels 33, 33, 34, 34 and 35 at the left and right ends of the wheel spindles 30, 31 and 32, respectively. 35 to the first, second, and third cylindrical axles 36, 36, 37, 37, 38, and 38.
, And each cylindrical axle 36, 36, 37, 37
38 and 38 are connected to the transmission unit 5 via the first, second, and third transmission mechanisms 39, 39, 40, 40, 41, and 41 so that the left and right traveling units 2.2 can be individually driven. I have.

As shown in FIG. 1 and FIG. 2, the drive shaft case 42
42 is formed by extending in the left-right direction.
42, the left and right drive shafts 43 are inserted through the first and third transmission mechanisms 39.
The input sections 39, 41 and 41 are connected and linked.

That is, the first transmission mechanism 39 is provided between the first drive sprocket 44 provided on the outer end of the drive shaft 43 and the first input sprocket 45 provided on the first cylindrical axle 36. 46 is formed by winding.

The second transmission mechanism 40 is provided between a first output sprocket 47 provided on the first cylindrical axle 36 and a second input sprocket 48 provided on the second cylindrical axle 37. Is formed by winding.

The third transmission mechanism 41 is provided between a third driving sprocket 50 provided on the outer end of the driving shaft 43 and a third input sprocket 51 provided on the third cylindrical axle 38. The chain 52 is formed by winding.

That is, the pair of running parts 2 on each of the left and right sides
First, second, and third wheel spindles 30, 31, and 32 extending laterally at the front, center, and rear of the body frame 1, respectively, are laterally extended. The first, second and third wheels 33, 33, 34, 34, 35, 3 respectively at the ends
5 to the first, second and third cylindrical axles 36, 36, 37 and 37
・ Attached via 38 ・ 38, each cylindrical axle 36 ・ 36
The right and left traveling sections 2 and 2 can be individually driven by linking 37, 37, 38 and 38 with the mission section 5.
In this way, the first, second, and
The third wheels 33, 33, 34, 34, 35, 35 can be driven by all wheels.

Then, the second wheel support shaft 31 for supporting the pair of left and right second wheels 34, 34 is attached to the pair of left and right longitudinally extending frame forming pieces 10, 10 by the ground height position adjusting mechanism 53.5.
It is installed so that the height above the ground can be freely adjusted via 3.

As shown in FIGS. 3 and 4, the ground height position adjusting mechanisms 53 are provided with fixed side adjusting pieces 54 extending vertically from a pair of left and right longitudinally extending frame forming pieces 10 and 10, respectively. In the center part of the side adjustment pieces 54, 54, the wheel support shaft guide grooves 55, 55 of the lower end opening are formed in a notch shape,
On the front and rear sides of the fixed side adjustment pieces 54, there are formed elongated slots 56 for adjustment extending in the vertical direction, respectively, while the movable side adjustment pieces 5 attached on the left and right sides of the second wheel support shaft 31, respectively.
7 and 57 are formed with bolt insertion holes 58 and 58 that match the long holes 56 and 56 for adjustment.
By adjusting and tightening the adjustment bolt 59 inserted in the second wheel 8, the second wheel support shaft 32 is moved to the movable adjustment pieces 57.
The height of the ground of the second wheels 34 can be adjusted (34 ') by appropriately adjusting the slide position in the vertical direction via the.

Furthermore, fine adjustment bolts 60 are attached to the left and right one longitudinally extending frame forming pieces 10 via bolt stays 61 with their axes directed substantially vertically. By adjusting the adjustment bolts 60 in the vertical direction, the fine adjustment bolts 60 can be adjusted.
The second wheel support shaft 31 that is in contact with the lower end surface of the wheel 60 can be finely adjusted in the vertical direction.

That is, the six-wheeled working vehicle A connects the left and right traveling units 2.2 to the prime mover unit 4 via the transmission unit 5, and drives the traveling units 2.2 individually from the transmission unit 5. The first, second, and third wheels are arranged at front, center, and rear portions at an interval in the front-rear direction.・ 34 allows the height of the ground to be adjusted.

As shown in FIG. 1, the driving section 3 extends a floor 65 on the front half of the guard frame 16 and a steering column 66 on the front of the floor 65. A steering wheel 68 is attached to the upper end of the wheel support shaft 67 by inserting a wheel support shaft 67 extending in the up and down direction, and the cam mechanism 69 is connected to the lower end of the wheel support shaft 67 and the mission unit 5 described later. A forward / reverse switching lever 180 is attached to the lower portion of the left side wall of the steering column 66, and the forward / backward switching lever 180 and a forward / reverse switching arm 181 provided on the transmission unit 5 described later are connected. The brake pedal 183 is provided at the front of the floor 65, and the brake pedal 183 and the brake provided at the transmission unit 5 are provided. And rk in operation arm 166, linked interlocked via a connection wire 185.

Then, the seat 186 is attached to the rear of the steering wheel 68 by the seat pivot brackets 14.
, And various operation levers are disposed on the left and right sides of the seat 186. That is, a speed change lever 187 is disposed on the left side of the seat 186, and the speed change lever 187 is connected and interlocked with the main speed change portion 97 and the auxiliary speed change portion 104 provided in the transmission portion 5 via a connection interlocking mechanism. A work implement elevating lever 188 is disposed on the right side, and the work implement elevating lever 188 is connected to and interlocked with a valve mechanism (not shown) for controlling the elevating cylinder 26 via a connection interlocking mechanism.

The prime mover unit 4 includes an engine 76 and a radiator, an air cleaner, and the like disposed near the engine 76. As shown in FIGS. 1 and 2, the transmission 5 is provided between the front support 20 and a pair of left and right rear supports 21, and a chain case 78 is connected to and linked to the left side of the transmission 5. On the other hand, a hydrostatic stepless speed change mechanism (hereinafter, referred to as “HST”) 74 for turning is connected and linked to the right side.

As shown in FIGS. 1, 5 and 7, the chain case 78 is formed by extending a case body 78a in the vertical direction, and has a transmission input shaft 7 mounted on the upper part of the case body 78a.
8b, the transmission input shaft 78b and the transmission unit 5
A transmission chain 78c is wound between one end of the first shaft 81 through sprockets 78d and 78e. And
The chain case 78 protrudes one end of the transmission input shaft 78b rightward from the case body 78a, and
A first transmission belt mechanism 125 is interposed between one end of the drive shaft 76a and the drive shaft 76a of the engine 76, and the power from the engine 76 is transmitted to the transmission input shaft 78b of the chain case 78. A second transmission belt mechanism 145 is provided between the drive shaft 76a of the engine 76 and the left end of the PTO shaft 24,
Power is transmitted to a working machine connected by the hitch body 27 disposed at the rear portion of the vehicle body frame 1.

Then, the mission unit 5 is constructed as shown in FIGS.
As shown in the figure, the first to ninth shafts 81, 82, 83, 84, 85, 86, 87 and 88 are provided inside the transmission case 80.
An input portion of the forward clutch 90a is fitted to a middle portion of the first shaft 81, and an end of the first shaft 81 is connected to the second shaft via a first meshing gear 91. 82, the input portion of the reverse clutch 90b loosely fitted in the middle portion and the working machine elevating hydraulic pump P are connected and interlocked, and the output side of the forward clutch 90a and the reverse The second shaft 82, which is the output side of the clutch 90b, is connected to the third shaft 83 in conjunction with the third shaft 83 so that the power transmission of the front / reverse clutches 90a and 90b can be exclusively selected so that the forward / backward switching of the driving direction can be performed. It is possible. In addition, 92 is a hydraulic pump input shaft.

Here, the forward and reverse clutches 90a and 90
b, a clutch on / off shifter 161 is attached to a shifter support shaft 160 laid horizontally on a front portion in the transmission case 80, and the clutch on / off shifter 161 is interlocked with the rotation of the shifter support shaft 160 in one direction. And forward clutch 90a
Is connected, the reverse clutch 90b is disconnected, and the forward clutch 90a is disconnected and the reverse clutch 90b is connected in conjunction with the rotation in the other direction so that the forward / reverse switching can be performed. I have.

A forward / reverse switching arm 162 is attached to the left end of the shifter support shaft 160, and a forward / backward switching lever 180 is connected to the forward / backward switching arm 162 via a connecting rod mechanism 182. Further, the third shaft 8
3 is connected to and linked with the input shaft 74a of the HST 74,
It is linked and interlocked with a fourth shaft 84, which is an input shaft of the main transmission 97, via a third meshing gear 96. The fourth shaft 84 has dogs 98 and 98 at both ends and a second speed driving gear 99 at the center. Is integrally slidably and non-rotatably fitted in the axial direction, and a constant meshing type is provided between the fourth shaft 84 and the fifth shaft 85 which is the drive shaft of the main transmission 97. The first and third speed meshing gears 101 and 102 are interposed, and a sliding mesh type second speed passive gear 103 is fitted to the fifth shaft 85 to form a slider 100.
The output rotation speed of the main transmission unit 97 can be switched in three stages by sliding.

An auxiliary transmission 104 is connected to the main transmission 97 in series. The auxiliary transmission 104 is connected to the fifth shaft 85 and a sixth shaft 86 as an output shaft of the auxiliary transmission 104. The high and low speed meshing gears 105 and 106 are interposed between the
Slider 10 axially slidably and non-rotatably fitted to 6
By the sliding of 7, the output rotation speed of the sub-transmission unit 104 can be shifted in two stages of high and low speeds with the neutral in between. As described above, the forward / reverse clutches 90a and 90b, the three-speed main transmission 97 and the two-speed auxiliary transmission 104 are connected and linked in series. Six-step shifting operation is possible.

As shown in FIG. 7, the sixth shaft 86 is connected to and linked to a seventh shaft 87 via a chain interlocking mechanism 108. The left and right sunshafts fitted to the left and right ends of the seventh shaft 87, respectively. Gears 110 and 111, left and right gauges 112 and 113 connected to left and right drive shafts 43 and 43 having the same axis as the seventh shaft 87, and a plurality of left and right shafts respectively mounted on the left and right gauges 112 and 113. Planetary gears 114 and 115,
The left and right ring gears 116 and 117 connected to and linked to the output shaft 74b of ST74 constitute left and right planetary gear mechanisms 118 and 119, and the left and right planetary gear mechanisms 118 and 119 are constituted by the above-described gear type transmission mechanism and meshing gears. Right and left sun gears 110 and 11
1 and a turning power transmission system H described later.
And the rotational power transmitted from the HST 74 to the left and right ring gears 116 and 117, respectively, and these combined rotational powers are combined into the left and right planetary gears 114 and 115 and the left and right gauges 112 and 1.
13 to the drive shafts 43 on the left and right sides individually.

A stopping brake portion 165 is provided on the left end of the sixth shaft 86, and the brake pedal 183 is connected to a brake operating arm 166 attached to the stopping brake portion 165 via an interlocking wire 184. It is linked and linked.

FIG. 7 shows an input shaft 74a of the HST 74.
As shown in FIG. 8, a forward / reverse rotation split mechanism 120 that transmits the rotation speed of the output shaft 74b to the left and right ring gears 116 and 117 in a complementary manner is located downstream of the turning brake unit 72 and connected and interlocked. I have.

The forward / reverse rotation dividing mechanism 120 is provided with an HS
An eighth shaft 88 is connected to and linked to the output shaft 74b of the T74 via a high / low speed switching mechanism 121, and the eighth shaft 88 is meshed with the first intermediate output gear 171 and the second intermediate output gear 171. The ninth shaft 89 is connected to and interlocked with the ninth shaft 89 via the intermediate output shaft 12, and left and right output gears 123 are provided at left and right ends of the ninth shaft 89, respectively.
124, the left output gear 123 and the left ring gear 1
16 are connected and linked via two idle gears (not shown) arranged in series, and the right output gear 124 and the right ring gear 117 are connected and linked via one idle gear 79 to reduce the rotational speed. Absolute value is equal but left ring gear 116
Transmits the rotation in the same direction as the ninth shaft 89, while transmitting the rotation in the opposite direction to the ninth shaft 89 to the right ring gear 117.

Then, one end of the first shaft 81, which is the input shaft of the transmission section 5, is projected from the left side wall of the transmission case 80, and the lower end of the chain case 78 is connected to and linked to the projected end. To the upper end of the chain case 78 and the drive shaft 76 of the engine 76.
and the steering wheel 68 is connected and interlocked via a first transmission belt mechanism 125, while the steering wheel 68 is connected and interlocked with the trunnion arm 75 of the HST 74 via a cam mechanism 69, and the steering wheel 68 is changed in accordance with the turning operation angle of the steering wheel 68. hand,
The gear ratio of the HST 74 can be changed steplessly in the forward and reverse directions. Reference numeral 126 denotes a shifter of the main transmission unit 97, 127 denotes a shifter of the sub transmission unit 104, and 128 denotes a front PTO shaft case for taking out power to the front outside.

Here, the turning brake unit 72 will be described. As shown in FIG.
A cylindrical input shaft 130 forming a part of the high / low speed switching mechanism 121 is spline-fitted to the output shaft 74b of the HST 74,
A wet multi-disc brake 131 is interposed between the cylindrical input shaft 130 and the transmission case 80, and the multi-disc brake 1
A wet multi-plate brake 131 is slid in the axial direction of the cylindrical input shaft 130 by disposing a shaft-shaped operating piece 132 in the vicinity of 31 and rotating the operating piece 132 around its axis. The braking action can be performed, and the lower end of the operating piece 132 is mounted on the transmission case 8.
The brake operating arm 73 is attached to the protruding end of the steering wheel 68 via a wheel support shaft 67.

The high / low speed switching mechanism 121 includes a low speed output gear 133 and a high speed output gear 13 on the cylindrical input shaft 130.
4 while the high-low speed switching shaft 135 is traversed close to the cylindrical input shaft 130, and the high-low speed switching shaft 135 meshes with the low-speed output gear 133.
6 and the high-speed input gear 137 meshing with the high-speed output gear 134, and both input gears 136, 13
7, a slider 138 is fitted so as to be slidable and non-rotatable in the axial direction.
The first output rotation speed can be shifted in two stages of high and low speeds with the neutral position interposed therebetween.

An output gear 139 is attached to the high / low speed switching shaft 135, and the output gear 139 is meshed with an input shaft 170 attached to the eighth shaft 88. In addition, the high / low speed switching mechanism 121 switches the speed to the high speed side in conjunction with the sub-shift operation of the shift lever 187.

Thus, the steering wheel 68
By simply setting the turning power transmission system H to the left / right steering neutral position, the turning brake unit 72 can brake the output shaft 74b of the HST 74 to bring the turning power transmission system H to a stopped state. As a result, only the straight-moving power transmission system M can be operated, and the straight-moving power transmission system M can ensure good straightness of the vehicle body.

The turning brake 72 is connected to an output shaft 74b of an HST 74 provided upstream of the turning power transmission system H.
Provided directly on the output shaft 7 with a small torque.
4b can be braked, and the power transmission of the turning power transmission system H can be reliably stopped even if the capacity of the turning brake portion 72 is reduced.

Further, by turning the steering wheel 68 in one of the left and right directions from the left / right steering neutral position, the brake braking of the turning brake portion 72 is released, and the vehicle body can be turned in the rotation direction. . Therefore, it is possible to improve the steering operability of the vehicle body, in particular, the straight traveling operability. Moreover, since the turning brake unit 72 uses the wet-type multi-plate brake 131, the width of the turning brake unit 72 in the axial direction can be reduced, and the turning brake unit 72 can be disposed in the transmission case 80 without any trouble. You can do it.

With the above-described configuration, the power from the engine 76 is shifted in six steps in the forward and backward directions to be transmitted to the left and right traveling units 2 and the output rotation speed of the HST 74 is changed according to the operation angle of the steering wheel 68. , Left and right traveling part 2.
The work vehicle A can be turned in the direction in which the drive speed has decreased by making the drive speeds of the drive wheels 2 different.

At this time, if the speed change lever 187 is operated in the sub speed operation, the high / low speed switching mechanism 121 is switched to the high speed side in conjunction therewith. In this case, the turning power transmission system H is accelerated, and the vehicle body can be turned by a small turning operation, so that turning performance suitable for the vehicle speed can be obtained, and the operational feeling of the operator can be improved. In this embodiment, the two HSTs 74 are connected to drive the left and right axles independently to steer and run the aircraft. However, two unconnected HSTs and two non-HST motors are used. The left and right axles can be provided independently on the left and right axles, respectively, and can be independently driven.

Here, the configuration of the wheelbase (wheel base) and wheelbase (tread) of the six-wheel working vehicle A according to the present invention will be described. As shown in FIG. 9, the first and second wheels 33 and 34
Is the wheelbase of Lc, and the wheelbase of the second and third wheels 34 and 35 is L
d, the wheelbase of the first and third wheels 33 and 35 is Lb. Then, the wheel distances of the first wheels 33, 33, the second wheels 34, 34, and the third wheels 35, 35 are slightly different from each other, but are assumed to be equal.

For example, as shown in FIG. 11, the wheel distance La is longer than the wheel distance Lb of the first and third wheels 33 and 35 (L
a> Lb) Assuming that the six-wheel working vehicle is B, when the six-wheel working vehicle B turns along the target inner wheel trajectory R of the turning inner front wheel 33, the vehicle body exerts a lateral force because the wheel distance La is large. As a result, the slip of the third wheels 35 increases, and the trajectory Kb of the third wheel 35 inside the turn is greatly expanded. Then, the difference in slip between the first wheels 33, 33 and the third wheels 35, 35 becomes large, and steering becomes difficult. Also, since the speed difference between the turning inner wheel and the turning outer wheel must be increased,
It is difficult to adjust the small left-right traveling direction. That is, the straightness is deteriorated.

As shown in FIG. 12, the wheelbase Lb of the first and third wheels 33 and 35 is longer than the wheelbase La (La <Lb), and the wheelbase La is second and the wheelbase La of the wheelbase La. Assuming that a six-wheeled working vehicle in which the wheelbase Ld of the three wheels 34, 35 is long (La <Lb) is C, the first and second wheels 33, 34 are in contact with the ground, and the inside turning front wheel 33 of the six-wheeled working vehicle C is turned. When turning along the target inner raceway R, the second and third wheels 34.3
Since the wheelbase Ld of No. 5 is large, the vehicle body receives a large rearward force, the slip of all the wheels including the first wheels 33 increases, and the trajectory Kc of the third wheel 35 inside the turn is greatly expanded. . When the second and third wheels 34 and 35 touch the ground and turn, the turning radius becomes large.

In contrast to the above-described six-wheeled working vehicles B and C, the six-wheeled working vehicle A according to the present invention has a shaft distance Lb of the first and third wheels 33 and 35 as shown in FIGS. (La <Lb), and the wheel distance Lc of the first and second wheels 33 and 34 and the wheel distance Ld of the second and third wheels 34 and 35 are shorter (La> Lc) than the wheel distance La. La> Lb). Therefore, as described above, the wheels 33
By arranging 34, 34, 35, 35, the vehicle body is supported in a well-balanced manner, and wheels 33, 33, 34, 34, 35,
35 is less slippery and the wheels 33, 33, 34
・ Before 34/35/35 slips and the vehicle body shakes left and right, the outer wheels rotate a lot by the operation of the steering HST 74, and the difference in slip between the first wheel 33/33 and the third wheel 35/35. , The trajectory Ka of the third wheel 35 on the inside of the turn can be kept substantially concentric with the target inner wheel trajectory R without swelling outward greatly, so that good steering of the vehicle body can be achieved.

[0048]

The present invention is configured as described above.
The following effects are obtained.

That is, as shown in claim 1, the front and rear three axles are provided with a pair of left and right first wheels, second wheels and third wheels, respectively, and the difference in the rotational speed between the left and right wheels allows the airframe to be mounted. In a six-wheel working vehicle with a turning mechanism, the first wheel, the second wheel, and the third wheel each have a shorter wheelbase than the wheelbase of the first wheel and the third wheel, and the first wheel, the second wheel, and the third wheel. Since the wheelbase of the first and second wheels and the wheelbase of the second and third wheels are configured to be shorter than the wheelbase of the wheels, the load concentrated substantially at the front and rear center where the mission portion is located is well-balanced to each wheel. It is supported, and extra load can be reduced when turning the vehicle body, so that the amount of wheel slip is reduced and the difference between the amount of slip between the first wheel and the third wheel is also reduced, so that it is possible to make a good turn and improve steerability It is.

According to a second aspect of the present invention, a pair of left and right first, second, and third wheels are provided on the front and rear three axles, respectively.
Connect two hydrostatic stepless transmission mechanisms, one for traveling,
The other is a six-wheel working vehicle which drives and steers an axle for steering (steering). The first wheel, the second wheel, and the third wheel are respectively based on the distance between the first wheel and the third wheel. The distance is short, and the first wheel, the second wheel, and the wheel distance of the second wheel and the third wheel are configured to be shorter than the wheel distance of the first wheel, the second wheel, and the third wheel. Since the load concentrated at the center of the front and rear positions is supported by each wheel in a well-balanced manner and extra load can be reduced when turning the body, the slip amount of the wheel is reduced, and the difference between the slip amount of the first wheel and the third wheel is also reduced. Because of the reduction, it is possible to make a good turn and improve steerability.

[Brief description of the drawings]

FIG. 1 is an overall side view of a six-wheeled working vehicle A according to the present embodiment.

FIG. 2 is a plan view showing a traveling unit.

FIG. 3 is a side view showing a ground height position adjusting mechanism of the second wheel.

FIG. 4 is a rear sectional view showing a ground height position adjusting mechanism of the second wheel.

FIG. 5 is a side view showing first and second belt transmission mechanisms.

FIG. 6 is a side view showing a mission unit.

FIG. 7 is a cross-sectional plan view of a transmission section showing a straight-ahead power transmission system.

FIG. 8 is a cross-sectional plan view of a transmission unit showing a turning power transmission system.

FIG. 9 is a plan view showing an arrangement configuration of wheels.

FIG. 10 is a diagram illustrating an example of a turning track of a six-wheel working vehicle.

FIG. 11 is a diagram illustrating an example of a turning track of a six-wheeled working vehicle.

FIG. 12 is a diagram showing a turning trajectory of the six-wheeled working vehicle according to the present invention.

[Explanation of symbols]

 A Six wheel working vehicle La Wheel span Lb / Lc / Ld Wheelbase 30/31/32 Axle 33 First wheel 34 Second wheel 35 Third wheel 74 Hydrostatic continuously variable transmission (HST)

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) // B62D 11/12 B62D 11/12

Claims (2)

[Claims] 1. A six-wheel working vehicle having a structure in which a left and right pair of first, second and third wheels are provided on three front and rear axles, respectively, and the body is turned by providing a difference in rotation speed between the left and right wheels. In, the first wheel from the wheelbase of the first wheel and the third wheel,
The wheel span of each of the second wheel and the third wheel is short, and the wheel span of the first wheel, the second wheel, and the second wheel and the third wheel is shorter than the wheel span of the first wheel, the second wheel, and the third wheel. A six-wheel working vehicle characterized by being configured to be short and small. 2. A three-axle front and rear axle is provided with a pair of left and right first, second and third wheels, respectively, and is connected to two hydrostatic stepless transmission mechanisms, one for traveling and the other for steering. In a six-wheel working vehicle in which the axle is driven and steered for (steering), the wheel distances of the first wheel, the second wheel, and the third wheel are shorter than the wheel distances of the first wheel and the third wheel. A six-wheel working vehicle characterized in that the wheelbases of the first wheel, the second wheel, and the second wheel and the third wheel are shorter than the wheelbases of the first wheel, the second wheel, and the third wheel. .