JPS63149228A - Front wheel transmission operating structure of working vehicle - Google Patents

Abstract

PURPOSE:To improve the simplification of the structure at a working vehicle, operation performance or the like by parallely installing a lever for switching the interconnection of a control handle with a front wheel transmission over the disengagement and a lever for running transmission, and interconnectingly controlling one lever to a safe side accompanied by the controlling of the other lever. CONSTITUTION:Around lateral axis P1 a first switching arm 9 is journalled and the arm 9 is connected to an auxiliary transmission through a rod 13, while around the lateral axis P1 a second switching arm 14 is also journalled and the arm 14 is connected to a front wheel transmission through a rod 16. In this case, between respective arms 9, 14 a switching levers 6 are journalled around the lateral axis P1 and the front and rear axis P2 and each pin 6a is engaged with each engagement arm 9a, 14a installed on each arm 9, 14 vertically. In addition around the lateral axis axis P1 an auxiliary transmission lever 7 is journalled and an engagement member 19 mounted thereon is engaged with the inside of control locus of one of engagement arm 14. The high speed and low speed positions H, L of the auxiliary transmission lever 7 respectively correspond to those of double-speed-IN and OUT positions of the switching lever 6.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention provides a transmission system for steerable front wheels with a standard drive state in which power is transmitted at a drive speed approximately equal to the rear wheel drive speed, and a rear wheel drive speed The front wheel transmission is equipped with a front wheel transmission that switches to an increased speed driving state in which transmission is performed at a higher drive speed, and the steering wheel and the front wheel transmission are linked to increase the front wheel transmission by steering operation from a straight-ahead state to a set angle or more. The present invention relates to a front wheel shift operation structure for a work vehicle configured to be operated to the speed drive side.

[Conventional technology]

Equipped with a front wheel transmission like the one mentioned above, it will not disturb the work ground (also, it will be possible to easily make sharp turns even on soft work ground, giving it excellent turning performance), but it will also allow you to drive at relatively high speeds. If the front wheel transmission is switched to the speed-increasing drive side when the vehicle is being steered while the vehicle is in the vehicle, a sudden turn at high speed will occur, creating a dangerous situation, so a safety mechanism is required to prevent this.

As a safety mechanism, when the switching lever that switches the steering wheel and front wheel transmission between linked and disengaged states is operated to the linked side, a stopper etc. prevents the operation of the speed change lever for driving to the high speed side. To prevent contact,
Furthermore, there is a model in which a stopper or the like is configured to prevent the switching lever from being operated toward the linking side when the speed change lever is operated to the high speed side.

[Problem that the invention seeks to solve]

Since the above-described configuration mechanically checks and prevents the lever operation itself, if the operator operates the lever with excessive force, there is a risk of damaging the stopper and the lever.

Also, for example, if you try to operate the shift lever to the high speed side in order to accelerate while driving straight with the changeover lever being operated to the linkage side, you will not be able to operate the shift lever to the high speed side due to the above-mentioned drag mechanism. Since it is necessary to operate the switching lever to the disengagement side and then operate the shift lever to the high speed side, there is room for improvement in terms of operability.

[Means for solving problems]

A feature of the present invention is that, in the above-mentioned front wheel transmission operation structure for a work vehicle, a switching lever for switching the operating handle and the front wheel transmission between a linked state and a released state and a driving gear shift lever are arranged side by side, The disengagement side position of the lever corresponds to the high speed side position of the gear shift lever, and the engagement side position of the switching lever corresponds to the low speed side position of the gear shifting lever, and at least one of the switching lever and the gear shifting lever , by providing an engaging member that enters the operation locus of the other lever, so that the shift lever is forcibly operated to the low speed side when the switching lever is operated to the linked side, and the shift lever is forced to be operated to the high speed side. The switching lever is configured so that it is forcibly operated to the disengagement side in accordance with this, and its functions and effects are as follows.

[For production]

For example, if the engagement member is provided on the gear shift lever, if the gear shift lever is operated from the low speed side to the high speed side in order to accelerate while driving straight with the switching lever operated to the linking side position, the engagement member provided on the gear shift lever will be removed. The engagement member comes into contact with the switching lever, and the switching lever is operated together with the speed change lever to the link release side position corresponding to the high speed side position of the speed change lever. Therefore, even if there is a subsequent steering operation, the front wheel transmission will not be switched to the speed-increasing drive side.

Additionally, if you operate the shift lever to the linking side while driving straight with the shift lever operated to the high-speed side in order to perform a turning operation using the front wheel speed increasing effect, the shift lever will come into contact with the engagement member and shift the gear. The lever is also moved and the gear shift lever is operated to the low speed side position, thereby ensuring safety when turning.

〔Effect of the invention〕

As described above, rather than using a stopper or the like to check and prevent lever operation toward a dangerous state, the other lever is operated in conjunction with the other lever to prevent a dangerous state from occurring due to the operation of one lever. With this structure, mechanical damage due to forced operation will not occur. Furthermore, the disadvantages of operability, such as having to operate the gear shift lever from the high speed side to the low speed side and then operate the ° switching lever to the linked side, have been improved, and the structure can be easily put together, reducing costs. It was an advantageous structure.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS A four-wheel drive agricultural tractor, which is one embodiment of the present invention, will be described below with reference to the drawings.

As shown in Fig. 3, a pair of left and right front wheels (1a).

(1b) so that it can be steered and driven, and a pair of left and right non-steering type rear wheels (2a) and (2b) that can be driven. Lift arm (3) that connects various work devices so that they can be raised and lowered
, and a power take-off shaft (4) for transmitting power to the working device, thereby forming a four-wheel drive type agricultural tractor.

Next, talking about the power transmission system, as shown in the figure, power from the engine (10) is transmitted from the main clutch (11), the power transmission shaft (12) to the main transmission in the mission case (8) and the high and low The power is transmitted to the auxiliary transmission (not shown) of the second gear, and the gears are changed to drive the rear wheels (2a) and (2b), and the power branched from the auxiliary transmission is transferred from the front wheel transmission shaft (15) to the front axle. It is sent to the front wheel transmission in the case (5) and is operated to change the speed of the front wheels (La) and (1'b).
It drives the.

This front wheel transmission has a standard drive state in which the front wheels (1a>, <1b) and rear wheels (2a), (2b) are driven at approximately the same speed, and a standard drive state in which the front wheels (1a), (1b) are driven at approximately the same speed. (2a).

It is configured to be switchable to an increased speed driving state in which the speed is increased compared to (2b). The front wheel transmission is linked to the steering wheel (28), and when the steering wheel (28) is steered beyond a set angle from a straight-ahead state, the front wheel transmission switches from the standard drive state to the accelerated drive state. It will be done.

Next, the front wheel transmission and the steering wheel (28) are put into the above-mentioned linked state and a disengaged state in which the front wheel transmission is maintained in the standard drive state regardless of the steering operation of the steering wheel (28). The configuration of the switching lever (6) and the sub-shift lever (7) for the sub-transmission device will be described in detail.
As shown in FIG. 1, a first switching arm (9) is pivotally supported around the horizontal axis (P,) of the control section. This is an arm that is linked to the sub-transmission device via a link rod (13) and switches between a four-wheel drive state and a rear two-wheel drive state where only the rear wheels (2a) and (2b) are driven.

Furthermore, a second switching arm (1
4) is rotatably supported. This is an arm that is connected to the front wheel transmission via a linking rod (16) and switches the control handle (28) and the front wheel transmission between a connected state and a disengaged state. And the first/second switching arm (9).

(14), a switching lever (6) is pivotally supported around a horizontal axis (Pl) and around a front-rear axis (P2). This switching lever (6) has a retaining pin (6a
) protrudes left and right, whereas the first and second
Engagement arms (9a) and (14a) stand up from the boss portions of the switching arms (9) and (14).

Swing the switching lever (6) around the longitudinal axis (h),
Push the pin (6a) of the switching lever (6) into the engagement arm (9).
a), (14a) engagement hole (9b), (14
b), the switching lever (6) swings one of the first or second switching arms (9), (14) around the horizontal axis (Pl). The operation pattern of this switching lever (6) is shown in FIG.
By operating the switching lever (6) along an inverted U-shaped lever guide (17) in plan view, a double speed on position is established in which the control handle (28) and the front wheel transmission are linked in a four-wheel drive state; It can be operated to the double speed off position, which is the standard drive state at all times, and the four-wheel drive off position, which is the four-wheel drive driver state and the rear two-wheel drive state, can be operated with the control handle (28) and the front wheel transmission disengaged. It is possible to switch between the states.

Further, a sub-shift lever (7) is located around the horizontal axis (Pl).
) is pivotally supported in a swingable manner, and an operating arm (7a) extending from the boss portion thereof is linked to the sub-transmission via a linking rod (18). This sub-shift lever (7) is provided with an engaging member (19).
) is connected to the engaging arm ( ) of the second switching arm (14).
The locking arm (14a) enters into the operating locus of the locking arm (14a).
It is located on the double speed input position side. As shown in Fig. 2, the high speed position (H) of the sub-shift lever (7) is made to correspond to the double speed off position of the switching lever (6), and the low-speed position (L) of the sub-shift lever (7) is made to correspond to the high speed position (H) of the sub-shift lever (7). This corresponds to the double speed on position of the switching lever (6).

By configuring as above, the switching lever (6)
is in the double speed position, and the sub-shift lever (7) is in the low speed position (L)
When the sub-shift lever (7) is moved to the high speed position (H) along the lever guide (20) while the gear is being operated,
The switching lever (6) is operated to the double speed off position via the engaging member (19). Conversely, switch lever (6)
is in the double speed off position, and the sub-shift lever (7) is in the high speed position (H)
When the switching lever (6) is operated to the double speed on position in the state where the gear shift lever (7) is operated, the sub-shift lever (7) is operated to the low speed position (L) via the engagement member (19). or,
The engagement member (19) is removable, and the engagement member (19) is removable.
9) It is also possible to eliminate such a restraining effect by removing it.

[Bessio side]

The lever guide of the switching lever (6) as shown in Figure 2 (
Instead of the shape of 17), it is also possible to adopt an operation pattern using a lever guide (17) as shown in FIG.

Further, as shown in Fig. 5, the first switching arm (9) for switching between the four-wheel drive state and the rear two-wheel drive state is attached to the switching lever (6), and the operation pattern is configured as shown in Fig. 6. You can.

Incidentally, although reference numerals are written in the claims section for convenient comparison with the drawings, the present invention is not limited to the structure shown in the accompanying drawings.

[BRIEF DESCRIPTION OF THE DRAWINGS] The drawings show an embodiment of the front wheel shift operation structure for a working vehicle according to the present invention, in which FIG. 1 is a front view of the switching lever and the surroundings of the shift lever, and FIG. Arrow view from n direction,
3 is an overall side view of the agricultural tractor, FIG. 4 is a plan view of the operation pattern showing the first concave side embodiment, and FIG. 5 is a front view of the switching lever and gear shift lever surroundings showing the second alternative embodiment. FIG. 6 is a view taken from the Vl-V1 direction in FIG. 5. (1a), (1b)...Front wheel, (6)...
...Switching lever, (7)...Speed lever,
(19)...Engagement member, (28)...
steering handle.

Claims (1)

[Claims] The transmission system for the steerable front wheels (1a) and (1b) has a standard drive state in which power is transmitted at a drive speed approximately equal to the rear wheel drive speed, and an increased speed drive state in which power is transmitted at a drive speed greater than the rear wheel drive speed. A front wheel transmission is provided, and the control handle (28) and the front wheel transmission are linked,
A front wheel transmission operation structure for a working vehicle is configured such that the front wheel transmission is operated to the speed-increasing drive side by a steering operation of a set angle or more from a straight-ahead state, wherein the steering handle (28
), a switching lever (6) for switching the front wheel transmission between a linked state and a released state, and a speed change lever (7) for driving are arranged side by side, and a switching lever (6) for switching between a linked state and a released state of the front wheel transmission and a speed change lever (7) for driving are arranged side by side. (7), correspond to the high speed side position, and change the switching lever (
6) and the low speed side position of the gear shift lever (7), and the switching lever (6) and the gear shift lever (7)
) is provided with an engaging member (19) that enters the operating locus of the other lever, so that when the switching lever (6) is operated to the linking side, the gear shift lever (7) is moved to the low speed side. so that the gear shift lever (7) is forcibly operated.
) is operated to the high speed side, the switching lever (6) is forcibly operated to the disengagement side.