JPH0699843A - Turning operation structure of working vehicle - Google Patents

Abstract

PURPOSE:To reduce the soil push-away action of travel devices at the turning time so as to lighten load to an engine and to enable smooth turning in the turning operation structure of a working vehicle constituted in such a way that a body is turned with difference given to the driving speed of a lateral pair of crawler type travel devices provided at the body. CONSTITUTION:The crawler grounding parts 21a of travel devices 4R, 4L are placed in the inclined attitude of being lower at the rear end than the front end, and the whole grounding part 21a is operated to descend. In association with turning, the grounding part 21a in the travel device 4L on the opposite side to the turning center is operated to descend as in the above-mentioned way so as to ground the travel device 4L almost over the whole length, and the grounding part 21a of the travel device 4R on the turning center side is placed in such a state that the front half part is grounded and the rear half part floats from the ground surface.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a turning operation structure for a work vehicle equipped with a pair of left and right crawler type traveling devices.

[0002]

2. Description of the Related Art As described above, when turning a work vehicle equipped with a pair of right and left crawler type traveling devices, one traveling device is driven to rotate at a lower speed than the other, or one traveling device is driven. A brake is applied or one of the traveling devices is driven in reverse to make a turn (corresponding to a turning operation means).
In the crawler type traveling device, the crawler is grounded for a long time in the front and rear, so when the above-mentioned turning is carried out, the crawler pushes the soil on the ground sideways. A heavy load is applied.
Therefore, as disclosed in, for example, Japanese Unexamined Patent Publication No. 59-84677, when the turning is started, the rear wheels of the left and right traveling devices are lifted (see FIG. 3 (a) in the above publication) to crawl. Some are configured to shorten the grounding length of. This reduces the amount of soil on the ground that is pushed away by the crawler when turning, and reduces the resistance when turning.

[0003]

In the above-mentioned structure, when the turning is started, not only the traveling device on the inside of the turning which is the turning center side, but also the traveling device on the outside of the turning which is the opposite side to the turning center, The trailing wheels in the second half have been lifted and the grounding length of the crawler has become shorter. When turning, it is considered that the driving force of the traveling device on the outside of the turn can change the direction of the aircraft, so if the ground contact length of the crawler on the outside of the turning becomes short, the driving force of the traveling device on the outside of the turning will be transmitted to the ground well. In some cases, smooth turning may not be possible. This is because when the ground contact length of the crawler is shortened, the driving force per unit ground contact area of the crawler is increased, and the crawler on the outer side of the turn easily slips. SUMMARY OF THE INVENTION It is an object of the present invention to provide a work vehicle equipped with a pair of left and right crawler type traveling devices so as to smoothly turn while suppressing the displacement of soil on the ground.

[0004]

A feature of the present invention resides in the following structure in the turning operation structure of a work vehicle as described above. That is, the pair of left and right crawler type traveling devices, the swing operation means for swinging the body by giving a difference in the driving speeds of the left and right traveling devices, and the ground portion of the crawler of the traveling device are arranged at the rear end rather than the front end. It is equipped with an elevating and lowering operation means for lowering the rearward and downward inclined posture and for operating the entire grounding portion to descend, and as the vehicle is turned by the turning operation means, ascending and descending on the outside of the turning side opposite to the turning center. There is provided control means for actuating the operating means on the descending side of the ground portion.

[0005]

It is assumed that the airframe is constructed as in the present invention and the aircraft is turned to the right, for example. When performing such a turning operation to the right,
For example, in the traveling device 4L on the left side (corresponding to the side opposite to the turning center) as shown in FIG.
1a is in a rearward-down inclined posture in which the rear end is lower than the front end, and the entire grounding portion 21a is operated to be lowered. As described above, when the ground contact portion 21a of the left traveling device 4L is operated to be lowered in the backward descending tilt posture, the aircraft tends to rise backward and slightly tilt to the right side (center of turning).
In this case, since the grounding portion 21a of the right traveling device 4R, which is the turning center side, is in a state parallel to the machine body, for example, as shown in FIG. 4, only the front half portion of the grounding portion 21a of the right traveling device 4R is grounded. Then the second half is in a slightly floating state. On the other hand, the left traveling device 4L on the opposite side of the turning center
The grounding portion 21a is grounded over substantially the entire length.

Therefore, when the vehicle turns right in the state shown in FIG. 4, the length of the ground contact of the right side (turning center side) traveling device 4R, which has a large degree of laterally pushing back the soil, is short.
The resistance applied to the right traveling device 4R becomes sufficiently small. Since the traveling device 4L on the left side (the side opposite to the turning center) that turns the machine body to the right is grounded over substantially the entire length,
The driving force per unit ground area of the crawler does not become too large, and the left traveling device 4L does not slip and the aircraft is smoothly turned to the right. In this case, the traveling device 4L on the left side (the side opposite to the turning center) pushes the soil on the ground sideways, but as compared with the traveling device 4R on the right side (turning center side), the left side (the turning center is The traveling device 4L (on the opposite side) has a larger turning radius and a smaller degree of pushing the soil on the ground sideways. Therefore, the resistance applied to the traveling device 4L on the left side (the side opposite to the turning center) is not so large.

Further, when the vehicle turns at a relatively high speed, the centrifugal force thereof causes the body to lean toward the side opposite to the turning center. In this case, when the ground contact portion of the traveling device on the side opposite to the turning center is operated to descend as in the present invention, the machine body is tilted toward the turning center side, and therefore the machine body is opposite to the turning center due to centrifugal force during turning. It is possible to suppress the state of leaning to the side.

[0008] When a straight working place such as a wet field is run straight, the weight of the vehicle body causes the entire vehicle body to sink, and the driving reaction force from the traveling device causes the front portion of the vehicle body to lift up. Therefore, in such a case, if the grounding portions of the left and right traveling devices are lowered and tilted downward as described above, the sinking of the airframe and the lifting of the front portion can be suppressed, and the airframe can be moved from the ground to a predetermined position. It can be maintained at the height of, and can be maintained horizontally in the front-back direction.

[0009]

As described above, the ground contact length of the traveling device on the side of the turning center where a large resistance is applied at the time of turning is shortened, and the ground contact length of the traveling device on the side opposite to the turning center for changing the direction of the machine body is left unchanged. By setting it, it becomes possible to smoothly turn while suppressing a large load on the engine, and it is possible to improve the turning performance of the work vehicle. Further, when the vehicle turns at a relatively high speed, it is possible to suppress the phenomenon that the machine body leans to the side opposite to the turning center, so that the turning performance of the work vehicle can be further improved. Further, even when going straight on a relatively soft work site, it is possible to prevent the body from sinking and the front part being lifted, so that it is possible to improve the straight running performance of the work vehicle.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. As shown in FIG. 5, a mowing unit 1 and a mission 2 for traveling (see FIG. 2) are mounted on the front part of the machine body, and a threshing device 3 is mounted on the rear part of the machine body. , 4L to form a combine, which is an example of a work vehicle.

Next, the crawler type traveling devices 4R and 4L will be described. As shown in FIGS. 1 and 2, the mission 2 is connected to the front side of the body of a fixed frame 5 on the body side via a pipe frame 22, and drive wheels 6 are provided at both ends of the pipe frame 22. A pair of support shafts 7 and 8 are rotatably supported in the front and rear of the frame 5, and support arms 9 and 10 facing rearward of the machine body are fixed to outer ends of the support shafts 7 and 8. A plurality of rolling wheels 11 and guide wheels 12 are supported by a track frame 13, and a rear end of a rear side support arm 10 is pivotally connected to the track frame 13. Around the horizontal axis P1 at the front of the track frame 13,
An intermediate link 14 is supported swingably back and forth, and a rear end of a front support arm 9 is pivotally connected to the intermediate link 14. Then, as shown in FIG. 1, the front support arm 9
The rear side support arm 10 is set to be longer than that. Each of the inner ends of both support shafts 7 and 8 has an operation arm 15 and
16 is fixed, and a double-acting hydraulic cylinder 18 is laid across the operation arm 16 on the rear side and the frame 17 on the machine body fixed side, and a link link 20 is laid over both operation arms 15, 16. Has been done.

With the above structure, when the hydraulic cylinder 18 is expanded and contracted to swing the rear side support arm 10 up and down, the linkage link 20 also swings the front side support arm 9 up and down at the same time. As a result, the entire track frame 13 can be moved up and down, and the traveling devices 4 on the left and right of the machine body can be operated.
By performing this operation in R and 4L, the lateral inclination of the aircraft can be corrected.

In this case, since the rear side support arm 10 is longer than the front side support arm 9, when the track frame 13 is lowered as described above, the track is indicated by the two-dot chain line in FIG. The amount of lowering of the frame 13 is larger on the rear side than on the front side. As a result, the ground contact portion 21a of the crawlers 21 of the traveling devices 4R and 4L can be placed in a rearward descending inclined posture in which the rear end is lower than the front end, and the entire ground contact portion 21a can be operated to descend (above. , Equivalent to the lifting operation means). When going straight through a relatively soft field such as a wetland, the weight of the vehicle body causes the entire vehicle body to sink, and the driving reaction force from the traveling devices 4R and 4L causes the front portion of the vehicle body to lift up. Therefore, in such a case, if the truck frames 13 of the left and right traveling devices 4R and 4L are lowered in the backward tilted posture as described above, the sinking of the vehicle body and the lifting of the front portion are suppressed, and the vehicle body is suppressed. Can be maintained at a predetermined height from the field and can be maintained horizontally in the front-back direction.

Next, a description will be given of a structure for turning the machine body by giving a difference in driving speed of the left and right traveling devices 4R and 4L. In the mission 2 shown in FIG. 2, the traveling devices 4R and 4L are installed.
Side clutch (not shown) that cuts off power transmission to the vehicle, a slow turning mechanism (not shown) that drives one of the traveling devices 4R and 4L in the forward direction at a lower speed than the other, and one of the traveling devices 4R and 4L is reversely rotated. A super-spindle turning mechanism (not shown) for driving is installed. The control section of the machine body is provided with an operating lever (not shown) for turning operation, which can be operated left and right.

When the operation lever is operated to the neutral position by the above structure, the left and right traveling devices 4R and 4L are driven at the same driving speed, and the machine body goes straight. Then, when the operation lever is operated from the neutral position to the right, for example, to the right first turning position, the right side clutch is disengaged, and the aircraft gently turns to the right. Next, it is assumed that the operation lever is further operated to the right and then to the right second turning position. In this case, if the gentle turning state is selected in advance, the gentle turning mechanism is activated, the right traveling device 4R is driven to rotate in the forward direction at a lower speed than the left traveling device 4L, and the machine body slowly turns to the right. Go (equivalent to turning operation means).

Next, assume that the super-spinning turning state has been selected in advance. In this case, if the operating lever is operated to the neutral position in the same manner as described above, the left and right traveling devices 4R and 4L are driven at the same driving speed and the machine body goes straight, and the operating lever is moved to the right first turn, for example. When operated to the position, the side clutch on the right side is disengaged and the aircraft gently turns to the right. Then, when the operation lever is operated to the second turning position on the right, the super-spindle turning mechanism is activated and the traveling device 4R on the right side is operated.
Is driven in the reverse direction, and the aircraft makes a super turning turn to the right (corresponding to turning operation means). In this way, it is possible to select in advance a gentle turning state with a large turning radius and a super-spinning turning state with a small turning radius.

Next, the turning of the body and the left and right traveling devices 4R,
The relationship with 4 L lifting and lowering will be described. As shown in FIGS. 3 and 1, in the state where the operation lever is operated to the neutral position (straightening state) and the first turning position to the right and left (disengagement state of the right or left side clutch) (step S1) The track frames 13 of the left and right traveling devices 4R and 4L are moved up to a predetermined position (see the solid line and the one-dot chain line in FIG. 1).

When the operating lever is operated to the right second turning position and the right traveling device 4R is driven at a low speed in the forward direction (slow turning state) or the reverse direction driving (super-spot turning state) ( Step S1), as shown by the chain double-dashed line in FIG. 1, the truck frame 13 of the left traveling device 4L is moved down (step S2) (corresponding to the control means). On the contrary, when the operating lever is operated to the left second turning position and the left traveling device 4L is driven in the forward direction at a low speed (slow turning state) or in the reverse direction (super-field turning state) (step S1). ), The track frame 13 of the right traveling device 4R is operated to descend as shown by the chain double-dashed line in FIG. 1 (step S3) (corresponding to control means).

For example, it is assumed that the right traveling device 4R is driven in the forward direction or the reverse direction at a low speed, and the track frame 13 of the left traveling device 4L is lowered. As described above, when the left track frame 13 is operated to be lowered in the backward tilting state, the aircraft tends to rise backward and tilt slightly to the right. In this case, since the track frame 13 of the right traveling device 4R is in a state parallel to the machine body, when the vehicle body tends to rise backward as described above, as shown in FIG. 4, the crawler 21 of the right traveling device 4R is grounded. In the portion 21a, only the front half is in contact with the ground and the rear half is in a slightly floating state. On the other hand, the grounding portion 21a of the crawler 21 in the left traveling device 4L is grounded over substantially the entire length.
Therefore, in the state shown in FIG. 4, the left traveling device 4L
The driving force causes the aircraft to make a gentle turn to the right or a super turning turn.

When the operation lever is returned from the right or left second turning position to the neutral position or the right and left first turning positions, the process proceeds from step S4 to step S5, and the descending right is operated. Or left track frame 1
3 is raised to the above-mentioned predetermined position.

[Other Embodiment] In the above-mentioned embodiment, if the operation lever is operated to the right and left second turning positions, the track frame 13 on the outer side of the turn is lowered regardless of the slow turn state and the super-sight turn state. Although it is operated, the lowering operation of the track frame 13 on the outer side of the turning is not performed in the gentle turning state of the large turning radius, and the lowering operation of the track frame 13 on the outer side of the turning is performed in the super turning turning state of the small turning radius. It may be configured as follows.

In the above-described embodiment, one of the traveling devices 4R, 4
It is configured to be able to select two states, a slow turning state in which L is normally driven at a low speed, and a super turning state in which one of the traveling devices 4R and 4L is driven in reverse. It may be configured such that a traveling turning state in which one of the traveling devices 4R and 4L is braked is provided, and the gentle turning state and the turning turning state can be selected in advance. In this case, the track frame 13 on the outer side of the turn may be lowered in both the gentle turn state and the turn-by-turn state, and the track frame 13 on the turn side may be lowered only in the turn-on state. You may comprise.

In the embodiment shown in FIG. 1 and FIG. 2, the rear support arm 10 is made longer than the front support arm 9 so that the track frame 13 is operated to be lowered in a rearward descending inclined posture. However, this may be configured as follows. That is, the front and rear support arms 9 and 10 are set to have the same length in FIGS. 1 and 2, and the hydraulic cylinder 18 is connected to the frame 5 instead of the fixed frame 17. And frame 5 is pipe frame 2
A double-acting hydraulic cylinder (not shown) for raising and lowering is erected over the frame 17 and the frame 5, which are fixed on the machine body side, while being supported so as to be vertically swingable around the connection point with the frame 2. . As a result, the frame 5 is oscillated downward by the hydraulic cylinder described above, and the hydraulic cylinder 1
By lowering the track frame 13 by means of 8, the track frame 13 is lowered in a rearward-down tilted posture.

It should be noted that reference numerals are given in the claims for convenience of comparison with the drawings, but the present invention is not limited to the configurations of the accompanying drawings by the entry.

[Brief description of drawings]

FIG. 1 is a side view of a crawler type traveling device.

FIG. 2 is a plan view of a crawler type traveling device.

FIG. 3 is a diagram showing a flow of control at the time of turning.

FIG. 4 is a plan view showing a grounded state of the crawler when turning right.

[Fig. 5] Overall side view of the combine

[Explanation of symbols]

 4R, 4L Traveling device 21 Crawler 21a Crawler grounding part

Claims (1)

[Claims] 1. A pair of left and right crawler type traveling devices (4
R) and (4L) and the left and right traveling devices (4R) and (4
L) the turning operation means for giving a difference to the driving speed to turn the vehicle body and the grounding portion (21a) of the crawlers (21) of the traveling devices (4R) and (4L) are arranged such that the rear end is lower than the front end. To the rear side and inclining downward, and the grounding part (21
a) is provided with an elevating and lowering operation means for lowering the entire body, and the elevating and lowering operation means on the outer side of the turning side opposite to the turning center is connected to the grounding portion (21a) along with the turning of the machine body by the turning operation means. A turning operation structure for a work vehicle, which is provided with control means for actuating on the descending side.