JPS63222927A - Front wheel speed change structure of working vehicle - Google Patents

Abstract

PURPOSE:To make it possible to turn a car easily without extensively roughening the work surface of land by providing a mechanism for changing the velocity ratio of a front wheel to a rear one in a speed-up driving state. CONSTITUTION:An operating handle 20 operated over a set angle causes the primary shift member 19 to leave a standard driving gear 18 for the forced engagement of a friction clutch 14. When the secondary shift member 21 is in previous engagement with the primary speed-up driven gear 16, the friction clutch 14 forcedly engaged by operating the operating handle 20 causes power transmission to a front wheel 1 in the primary speed-up state in which the driving speed of the front wheel 1 is higher than that of the rear wheel 2, and when the secondary shift member 21 is in engagement with the secondary speed-up driven gear 17, the power transmission to the front wheel 1 is performed in the secondary speed-up driving state in which the driving speed of the front wheel 1 is increased more than that in the primary speed-up driving state.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a front wheel transmission structure used in a four-wheel drive type work vehicle.

[Conventional technology]

In an agricultural tractor, which is an example of a four-wheel drive type work vehicle, as disclosed in, for example, Japanese Unexamined Patent Publication No. 60-4470, there is a standard drive state in which power is transmitted at a drive speed approximately equal to the rear wheel drive speed; Models have appeared that are equipped with front wheel transmissions that can be operated to switch between an increased speed drive state in which transmission is performed at a drive speed greater than the rear wheel drive speed.

The disclosed structure is configured so that when the steering wheel is turned beyond a set angle, the front wheel transmission is switched from the standard drive side to the speed-up drive side, which allows the front wheel transmission to be operated even on soft ground. This allows you to make sharp turns with ease.

[Problem that the invention seeks to solve]

The conditions of the working ground where agricultural tractors and other work vehicles drive are as follows:
In contrast, in the conventional configuration, the gear ratio of the front wheels to the rear wheels is constant in the increased speed drive state, so the drive state of the front wheels changes when turning. The turning conditions of the front part of the aircraft did not match well, and there were cases where the front wheels would ruin the work surface.

The present invention has focused on the above-mentioned problem, and aims to provide a structure that allows sharp turns to be made without particularly roughening the work ground.

[Means for solving problems]

The feature of the present invention is that the above-mentioned front wheel transmission structure of a working vehicle is equipped with a changing mechanism that changes the speed ratio of the front wheels to the rear wheels in the speed increasing drive state, and its operation and effects are as follows. It is as follows.

[For production]

When equipped with the above-mentioned transmission mechanism, depending on the conditions of the working ground, for example, in general fields where sharp turns can be made without worrying about the roughness of the ground surface, the speed increase ratio of the front wheels to the rear wheels can be increased (e.g. 2 times), or if you want to make a small turn on a grassy field without disturbing the grass, you can set the speed increase ratio to be slightly smaller (for example, 1.5 times). be.

〔Effect of the invention〕

As described above, it is now possible to arbitrarily set the speed increase ratio of the front wheels to the rear wheels during turning according to various working surfaces and turning conditions, making it easier to perform turns without disturbing the working surface. Became.

〔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 Figure 2, the fuselage frame (
3) is equipped with an engine (4), main clutch (5), transmission case (6), and control unit (7), and a lift arm (8) and A four-wheel drive agricultural tractor is constructed by providing a PTO shaft (28) for transmitting power to the working device.

Next, we will explain the power transmission system of agricultural tractors in detail.
As shown in Figure 2, power from the engine (4) is transmitted to the main transmission (not shown) and sub-transmission (not shown) in the mission case (6) via the main clutch (5). At the same time, the power branched from the sub-transmission device passes through the front-wheel transmission (10) and is sent from the front export power shaft (15) to the front-wheel differential mechanism (1a).

Next, the front wheel transmission (10) will be described in detail.
As shown in the figure, a transmission shaft (9) for receiving and taking power from the sub-transmission device is arranged parallel to the front export power shaft (15), and a standard drive gear (9) is connected to the transmission shaft (9). 11), a first speed increasing drive gear (12), and a second speed increasing drive gear (13) are fixed. On the other hand, a multi-disc friction clutch (14) is provided on the front export force shaft (15), and a boss portion of the clutch case (14a) which is in an idling state with respect to the front export force shaft (15) is provided with a multi-disc friction clutch (14). , first and second speed-increasing driven gears (16) and (17) meshing with the first and second speed-increasing drive gears (12) and (13) are fitted loosely and externally.

A standard driven gear (18) that meshes with the standard drive gear (11) is freely fitted onto the front export force shaft (15), and is connected between the standard driven gear (18) and the friction clutch (14). A first shift member (19) is attached with a spline structure to. Normally, the first shift member (19) engages with the engagement part (18a) of the standard driven gear (18), and the front wheel (1) and the rear wheel (2) are in a standard drive state where the drive speeds are approximately equal. Power is transmitted to (1).

The first shift member (19) is linked to a control handle (20), and when the control handle (20) is operated to a preset angle or more, the first shift member (19) is connected to a standard driven gear (18). Further apart friction clutch (14)
Press in to operate. On the other hand, the friction clutch (14
) has a second shift member (2) in the clutch case (14a).
1) is attached with a spline structure, and if this second shift member (21) is engaged with the first speed increasing driven gear (16) in advance, the control handle (20)
When the friction clutch (14) is pressed into operation by the operation of is being transmitted.

When the second shift member (21) is operated to engage the second speed increasing driven gear (17), the friction clutch 7 (14) is pressed based on the operation of the control handle (20). Power is transmitted to the front wheels (1) in a second speed-up drive state in which the speed is further increased by operation compared to the first speed-up drive state. As described above, it is possible to shift the speed increasing drive state of the front wheels (1) to two stages.

[Another example]

In the above-described configuration, the speed-up drive state is controlled by the second shift member (21
), but a structure in which a friction-type continuously variable transmission mechanism is configured between the transmission shaft (9) and the thalassochi case (14a) of the friction clutch (14) can also be adopted.

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 explanation of the drawing]

The drawings show an embodiment of a front wheel transmission structure for a working vehicle according to the present invention, and FIG. 1 is a side view of the front wheel transmission, and FIG. 2 is a side view of the entire agricultural tractor. (1)...Front wheel, (2)...Rear wheel, (
10)...Front wheel transmission.

Claims (1)

[Claims] The transmission system to the steerable front wheels (1) is switched between 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. work in which the front wheel transmission (10) is configured so that the front wheel transmission (10) is switched to the speed-increasing drive side by a steering operation of the steering handle (20) at a set angle or more. A front wheel transmission structure for a working vehicle, the structure comprising a changing mechanism for changing the speed ratio of a front wheel (1) to a rear wheel (2) in the speed increasing drive state.