JPH0725274B2 - Four-wheel drive work vehicle - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a standard drive state in which power is transmitted to a front wheel that is steerable and steerable at a drive speed substantially equal to a rear wheel drive speed, and a rear wheel drive. A front wheel transmission that switches to a speed-up drive state in which the transmission is performed at a driving speed higher than the speed is provided, and the front wheel transmission is operated by steering the front wheel steering mechanism and the front wheel transmission from a straight traveling state at a set angle or more. The present invention relates to a four-wheel drive work vehicle that is linked so as to be operated on the speed-increasing drive side.

[Conventional technology]

When the front wheel transmission as described above is provided, the work ground is not roughened, and a sharp turn can be easily performed even on a soft work place, so that the turning performance is excellent. If the front wheel transmission is switched to the speed-increasing drive side when the steering operation is performed while traveling at high speed, the vehicle makes a sharp turn at high speed, which makes it difficult to steer. Is not needed.

Therefore, it is necessary to have a mechanism to restrain the steep turn at high speed so that it does not appear.In the past, however, a switching lever that switches the steering wheel and the front wheel transmission to the linked state and the unlinked state is operated on the linked side. When the gearshift lever is operated to the high speed side, the shift lever for traveling is pressed against the high speed side, and when the gearshift lever is operated to the high speed side, the shift lever is moved to the linkage side. The operation of was blocked by a stopper or the like.

[Problems to be Solved by the Invention]

Since the above-mentioned conventional structure mechanically restrains the lever operation itself, if the operator operates the lever with an excessive force, the stopper or the lever may be damaged.

In addition, for example, even if the shift lever is operated to the linkage side and the gear shift lever is operated to the high speed side in order to accelerate straight ahead, the gear shift lever cannot be operated to the high speed side due to the drafting work as described above. There was room for improvement in terms of operability, because the shift lever had to be operated once to the linkage release side and then to the speed change lever.

Here, the present invention has been made in view of the above situation, and in a four-wheel drive type work vehicle, a switching lever for switching the front wheel transmission to an operating state and an operation releasing state, and a traveling transmission lever. The purpose is to improve operability.

[Means for Solving the Problems]

In order to achieve the above object, the present invention provides a power transmission system to a front wheel which can be steerably operated, in a standard drive state in which a drive speed is substantially equal to a rear wheel drive speed, and in a drive speed higher than a rear wheel drive speed. The front-wheel transmission is switched to the speed-increasing drive side by operating the front-wheel steering mechanism and the front-wheel transmission in cooperation with each other so that the front-wheel steering mechanism and the front-wheel transmission are linked to each other, and the steering operation is performed at a set angle or more. In the four-wheel drive work vehicle that is linked as described above, a switching operation unit that switches the front wheel steering mechanism and the front wheel transmission to the linked state and the unlinked state is provided, and the gear shift lever and the switching lever for traveling are provided in the machine body. A second linkage mechanism that laterally distributes the shift lever and the switching operation unit, and
The second linkage mechanism and the first linkage mechanism for linking the switching lever are provided, and when the speed change lever is operated to the high speed side, the switching operation section is forcibly switched to the linkage release side and the switching lever is operated to the linkage side. Then, there is provided a linking operation means for linking the shift lever and the first and second linking mechanisms so that the shift lever is forcibly switched to the low speed side.

[Work]

With the configuration described above, for example, if the speed change lever is operated to the high speed side to accelerate while the vehicle is moving straight while the switch lever is operated to the linkage side, the speed change lever is moved to the high speed side without receiving a draft production. It can be operated, and the switching lever is operated to the linkage release side in conjunction with this operation. Therefore, even if the steering operation is performed thereafter, the front wheel transmission is not switched to the speed increasing drive side.

Also, if the speed change lever is operated in the high speed side and the vehicle is moving straight ahead, if the switching lever is operated to the linkage side so as to make a turning operation by utilizing the front wheel speed-increasing action, the speed change lever is moved to the low speed side in conjunction with this operation. Since the aircraft automatically decelerates when it is operated, it prevents the traveling state where the vehicle makes a sharp turn at high speed from appearing.

Since the switching lever and the shift lever that are operated in a mutually contradictory state are arranged separately on the left and right sides of the machine body, erroneous operation due to misholding of the lever can be prevented as compared with the case where they are arranged close to each other. By arranging the shift lever in the middle of the linkage mechanism from the shift lever to the shift operation unit of the front wheel transmission, the shift lever and the linkage between the shift lever and the shift operation unit are not large in structure, and the structure is simple. It becomes easy to do.

〔The invention's effect〕

As described above, the lever operation to the side where a rapid turn at high speed is revealed by the operation of the link operation means,
Since the stopper is not used to prevent the restraint, the levers are forcibly operated to the low speed or the uncoupling side by the linkage of the levers, so that the mechanical damage due to the excessive operation is eliminated. Further, it is not necessary to perform a compound operation such as operating the shift lever from the high speed side to the low speed side and then operating the switching lever to the link side, and the lever operability is improved such that the single lever operation enables quick operation. As a result, it is possible to prevent erroneous operation due to misholding of the lever,
Further, it has become possible to simplify the linking structure between the switching lever and the shift lever.

〔Example〕

A four-wheel drive agricultural tractor, which is one of the embodiments of the present invention, will be described below with reference to the drawings.

As shown in FIG. 2, an engine (3) and a clutch (4) are provided at the front of the airframe supported by front wheels (1) and rear wheels (2),
A four-wheel drive agricultural tractor is configured by arranging a control section (5) at the center of the machine body and a mission case (6) at the rear part of the machine body.

The power from the engine (3) passes through a clutch (4) and a first transmission shaft (7) as shown in the figure, and a main transmission device and an auxiliary transmission device (not shown) in the transmission case (6).
Is transmitted to the rear wheels (2) and is transmitted to the front wheels transmission (9) connected to the lower part of the clutch (4) via the second transmission shaft (8). And transmitted from the third transmission shaft (10) to the front wheel (1). The front wheel transmission (9) has a standard drive state in which the front wheel (1) and the rear wheel (2) are driven at substantially the same speed, and a speed-up drive in which the front wheel (1) is accelerated more than the rear wheel (2). It is configured to be switchable between two states. Then, in a normal straight traveling state, the knuckle arm (not shown) of the front wheel (1) is in a standard drive state so that when the front wheel (1) is steered by a set angle or more, the front wheel (1) is switched to the speed-increasing drive side. No.) and the front wheel transmission are mechanically linked to each other.

Next, when the front wheel (1) is operated to steer beyond the set angle, the front wheel transmission (9) is switched to the speed-increasing drive side, and the front wheel (1) is steered to above the set angle. Even if the operation system for switching to the disengaged state in which the switching operation is not performed to the speed-up drive side is described in detail, the front wheel transmission (9) is located below the clutch (4) as shown in FIGS. 1 and 2. A switching operation part (11) for switching between the linked state (A) and the linked state (B) is provided on the left side surface of the front wheel transmission (9).

On the other hand, the switching lever (13) is located on the right side of the control section (5) opposite to the switching operation section (11) with respect to the cockpit (12).
Is rotatably supported around a horizontal axis (P ₁ ) and is rotatable about a horizontal axis (P ₂ ) below the cockpit (12) as a first linkage mechanism (14). The rotation shaft is supported, and one end of the switching lever (13) and the rotation shaft (14) are interlockingly connected via a rod (15).

Then, the other end of the pivot shaft (14), i.e. with the left side of the horizontal axis (P ₃₎ rotates around freely plate-like restraint member of the cockpit (12) (16) is supported, rotated A rod (17) is installed over the other end of the shaft (14) and the check member (16), and a switching shaft (11) of the support shaft (18) of the check member (16) and the front wheel transmission (9). The rod as the second linking mechanism (19) is laid across.

With the above structure, by swinging the switching lever (13) around the horizontal axis (P ₁ ), the switching operation part (11) of the front wheel transmission (9) is disengaged from the linked state (A). The operation can be switched to the state (B) side.

On the other hand, on the left side of the cockpit (12), the auxiliary transmission lever (20) that shifts the auxiliary transmission in the mission case (6) between high and low gears swings around the horizontal axis (P ₄ ). The rod (21) is movably supported, and extends over the elongated hole (16a) of the check member (16) and the auxiliary transmission lever (20).
In the state shown in FIG. 1, the switching lever (13) is in the linked state (A).
Side, and the auxiliary shift lever (20) is operated to the low speed (L) side. If the auxiliary shift lever (20) is operated to the high speed (H) side in this state, the rod (21) moves the auxiliary shift lever. The lever (20) side is pulled, and the switching lever (13) and the switching operation part (11) are operated to the link release state (B) side via the restraining member (16) and the rods (14) and (19). It is.

On the contrary, when the switching lever (13) is operated to the linkage released state (B) side and the sub-transmission lever (20) is operated to the high speed (H) side, the switching lever (13) is linked state (A). When operated to the side, the rod (21) is pulled to the restraining member (16) side, and the auxiliary transmission lever (20) is operated to the low speed (L) side. Then, the long hole (16
The rod (21) is engaged in (a) when the sub speed change lever (20) is operated to the low speed (L) side, and the switching lever (13) is also operated to the disengaged state (B) side. This is to be able to do it.

In short, the speed change lever (20) and switching lever (1
3) and are placed separately on the left and right sides of the machine, and the shift lever (2
The second link mechanism (1) that links the switch 0 (0) and the switching operation unit (11).
9) and the second linkage mechanism (19) and the switching lever (1
3) is provided with a first linkage mechanism (14), and when the speed change lever (20) is operated to the high speed side, the switching operation part (11) is forcibly switched to the linkage release side and the switching lever (13) )
So that the gear shift lever (20) is forcibly switched to the low speed side when the gear is operated to the linkage side, the linkage operation for linking the gear shift lever (20) with the first and second linkage mechanisms (14) and (19) Means (R) are provided. The linking operation means (R) is composed of a restraint member (16), a rod (17), a support shaft (18), a rod (21) and the like.

Further, in the third transmission shaft (10) from the front wheel transmission (9) to the front wheel (1), as shown in FIG. 3 and FIG.
It has a split structure of the shaft (10a) and the second shaft (10b),
The first shaft (10a) and the second shaft (10b) have three sets of balls (10
c) and the structure in which the ball (10c) is connected to the collar (10d) so that the third transmission shaft (10) can be bent at a slight angle at the portion of the ball (10c). .

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

[Brief description of drawings]

The drawings show an embodiment of a four-wheel drive type working vehicle according to the present invention,
FIG. 1 is a perspective view showing a linkage structure of a switching lever and a gear shift lever and a front wheel transmission, FIG. 2 is an overall side view of an agricultural tractor, and FIG. 3 is a vertical cross-section of a third transmission shaft from the front wheel transmission to the front wheels. A side view and FIG. 4 are sectional views taken along the line IV-IV in FIG. (1) …… Front wheel, (9) …… Front wheel transmission, (11) ……
Switching operation part, (13) ... switching lever, (14) ... first link mechanism, (19) ... second link mechanism, (20) ... shift lever, (R) ... link operation means.

Claims (1)

[Claims] 1. A transmission system for a front wheel (1), which is capable of steering operation,
A front wheel transmission (9) is provided for switching between a standard drive state in which transmission is performed at a drive speed substantially equal to the rear wheel drive speed and an increased drive state in which transmission is performed at a drive speed higher than the rear wheel drive speed. A four-wheel drive work vehicle in which the front wheel transmission (9) is linked so that the front wheel transmission (9) is operated to the speed-increasing drive side by steering operation from a straight traveling state at a set angle or more. There is provided a switching operation part (11) for switching the front wheel steering mechanism and the front wheel transmission (9) into a linked state and a released state, and a traveling shift lever (20) and a switching lever (13). And 2 are arranged so as to be laterally separated from each other in the lateral direction of the machine body, and the second linkage mechanism (1) for linking the speed change lever (20) and the switching operation part (11)
9) and a first linking mechanism (14) linking the second linking mechanism (19) with the switching lever (13), and the shift lever (20) is operated to the high speed side. The shift lever (20) is forcibly switched to the linkage release side, and when the switch lever (13) is operated for the linkage side, the shift lever (20) is forcibly switched to the low speed side. (20) and first and second linkage mechanisms (14), (19)
A four-wheel drive work vehicle provided with a link operation means (R) for linking and.