JPS63301114A - Working vehicle - Google Patents

Abstract

PURPOSE:To enhance swing performance in a working vehicle to which an axle case supporting driving wheels is attached while being freely rolled around a longitudinal shaft center of a body by providing mechanisms which regulate the axle case rolling in such a way that the driving wheel of swinging of outside lifts. CONSTITUTION:A front axle case 11 is supported on a body frame through a bracket 11, while being freely rolled around a longitudinal shaft center P1 is concentric with a front wheel output shaft 15. In this case, in right and left of the top face of the front axle case 11, a pair of L-shaped rolling regulation mechanisms 23A, 23B which are respectively rotatable around a longitudinal shaft center P2 are provided. Respective regulation mechanisms 23A, 23B are connected to respective side brake pedals 26a, 26b of right and left in such a way to cross through springs 24 and wires 25 respectively. With this arrangement, for example, when the right side pedal 26a is stepped on at the time of right side swinging, the left side reguration mechanism 23B enters a left side contact portion 22 of the front axle case 11 so as to prevent a front wheel of left side from lifting.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention applies to working vehicles such as agricultural tractors and riding rice transplanters, in particular when the front wheels for driving and steering and the rear wheels for driving are connected to the vehicle body. This invention relates to a work vehicle that is supported so as to be able to roll freely around its front and rear axes.

[Conventional technology]

A four-wheel drive agricultural tractor is an example of a work vehicle.
For example, as disclosed in Japanese Utility Model Application Publication No. 61-135704, there is a structure in which the front wheel case is mounted so that it can freely roll around the front and rear axes of the fuselage, and this free rolling structure allows it to move freely on uneven surfaces on the ground. Even if there is a difference, the left and right front wheels follow this, and the ground contact pressure of the left and right front wheels is maintained at approximately the same level.

[Problem that the invention seeks to solve]

When traveling straight, the rotational speed of the left and right front wheels is approximately equal, so as mentioned above, free rolling maintains the ground pressure of the left and right front wheels approximately equal, allowing the driving force of the left and right front wheels to be transmitted to the ground without waste. However, when making a sharp turn, the front wheel on the outside of the turn rotates at a higher speed than the front wheel on the inside of the turn due to the action of the differential mechanism, so if the ground pressure of the left and right front wheels is approximately equal as described above, The front wheel on the outside of the turn is likely to slip.

Therefore, if the front wheel on the outside of the turn slips in this condition, the driving force will not be sufficiently transmitted to the ground, resulting in a decline in turning performance. It is thought that this phenomenon similarly occurs in the rear wheels of work vehicles such as riding-type rice transplanters, which are of a rear two-wheel drive type and have a rolling rear axle case.

The present invention focuses on the above-mentioned problem and aims to prevent the deterioration of the turning performance of a working vehicle in which the axle case supporting the drive wheels rolls.

[Means for solving problems]

A feature of the present invention is that the above-mentioned work vehicle is provided with a rolling restriction mechanism that prevents the axle case from rolling in a direction in which the drive wheel on the outside of the turn moves upward when a sharp turn is made. Its functions and effects are as follows.

[For production]

When turning, the centrifugal force swings the aircraft to the outside of the turn.
It will be in a state where it is slightly tilted outward. Therefore, when the rolling restriction mechanism operates as described above during a sharp turn and prevents the upward rocking of the drive shaft on the outside of the turn, the ground pressure of the drive wheel on the outside of the turn changes to the ground pressure of the drive shaft on the inside of the turn. This makes it difficult for the drive wheels on the outside of the turn to slip even when rotating at high speed.

〔Effect of the invention〕

As described above, by reducing the slip of the drive wheels on the outside of the turn, the driving force is transmitted to the ground from the drive wheels on the outside of the turn, where the ground contact pressure is high, without waste, which improves the turning performance of the work vehicle. This will prevent a decrease in

〔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. 4, the fuselage frame (3) supports the front and rear wheels (2) as a pair of left and right drive wheels (1) in a freely drivable manner, includes an engine (4), a main clutch (5), and a transmission case. (6) and a control section (7), a lift arm (8) that connects various working devices such as a rotary tiller to the rear of the aircraft so that it can be raised and lowered, and a PTO shaft (9) that transmits power to the working devices. This is a four-wheel drive agricultural tractor.

Regarding the power transmission system of agricultural tractors, as shown in Figures 3 and 4, power from the engine (4) is transmitted through the main clutch (5) to the main transmission and sub-transmission in the transmission case (6). The transmission is transmitted to the transmission (not shown), and is transmitted from the rear wheel differential drive shaft (12) to the side of the rear wheel differential machine (2a).
At the same time, the power branched from the rear wheel differential drive shaft (12) is transmitted to the front wheel transmission (10), and is transmitted to the front wheel differential mechanism in the front axle case (11) via the front export power shaft (15). (not shown).

As shown in FIG. 3, the front wheel transmission (10) has a front export power shaft (15) installed in parallel with the rear wheel differential drive shaft (12), and a first - The second drive gears (13) and (14) are fixed. The first and second driven gears (16) and (17) that mesh with the first and second driving gears (13) and (14) are freely fitted onto the front export force shaft (15). A first hydraulic clutch (18) is connected between the first driven gear (16) and the front export force shaft (15), and a first hydraulic clutch (18) is connected between the second driven gear (17) and the front export force shaft (15).
) is configured with a second hydraulic clutch (19).

In a normal straight-ahead state, the first hydraulic clutch (1
Hydraulic oil is supplied to the first hydraulic clutch (18) and the power is applied to the front wheels (1) and rear wheels (18).
2) is transmitted in a standard driving state in which the driving speeds are approximately equal.

When the steering wheel (20) is operated to an angle greater than or equal to the set angle, this is detected electrically and the front wheel shift speed (1
A control valve (not shown) for the first hydraulic clutch (
18) The second hydraulic clutch (19) is switched from the hydraulic oil supply side to the hydraulic oil supply side. As a result, in an accelerated drive state where the front wheel (1) is accelerated more than the rear wheel (2),
Power is transmitted.

Next, the structure around the front axle case (11) will be described in detail.As shown in Figs.
) is supported by the fuselage frame (3) via a bracket (21) so as to be able to roll freely around the front export force shaft (15) and the front and rear axle center (Pl) of the front axle case (15).
Convex abutting portions (22) are provided on the left and right upper surfaces of 1), and normally the abutting portions (22) are attached to the fuselage frame (3).
The front axle case (11) rolls until it comes into contact with the protrusion (27) on the lower surface.

The front axle case (11) has a vertical axis (
P2) L-shaped rolling regulation mechanism that can be rotated freely (
Regulation members 23A) and (23B) are provided. As shown in both figures, these regulating members (23A) and (23B) are connected to the right rear wheel (2) which can independently brake the right rear wheel (2) via a flexible spring (24) and wire (25). The left hand brake pedal (26b) is connected to the left hand brake pedal (26a) and the left regulating member (23B), and is capable of independently braking the left rear wheel (2).
and the right regulating member (23A) are connected.

For example, if you perform a right turn operation using the steering wheel (20) and press the right side brake pedal (26a),
The front wheel transmission (10) speeds up the front wheel (1) more than the rear wheel (2) and brakes the right rear wheel (2), allowing a sharp turn to the right. and the end (23b) of the left regulating member (23B) as shown in FIG.
) enters between the left abutment part (22) of the front axle case (work 1) and the protrusion (27) on the bottom of the fuselage frame (3), causing the left front wheel (1) to lift upward. This prevents the axle case (11) from rolling.

Also, if you perform the operation opposite to the above, the right regulating member (23A
) end (23a) fits between the right abutting part (22) and the protrusion (27) on the lower surface of the fuselage frame (3).

Further, the present invention may be applied to a four-wheel drive type work vehicle that is not equipped with a front wheel transmission (10), or may be applied to a riding type rice transplanter that is driven by two rear wheels and has a rolling rear axle case.

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 drawings]

The drawings show an embodiment of the work vehicle according to the present invention, in which Fig. 1 is a plan view of the area around the front axle case when the right side brake pedal is pressed and operated, and Fig. 2 is the front axle case in the state shown in Fig. 1. 3 is a longitudinal sectional side view of the front wheel transmission, and FIG. 4 is an overall side view of the agricultural tractor. (1)... Drive wheel, (11)... Axle case, (23A).

Claims (1)

[Claims] This is a work vehicle in which the axle case (11) that supports the drive wheel (1) is installed so that it can roll freely around the longitudinal axis (P_1) of the machine body, and when a sharp turn is made, the drive wheel (1) on the outside of the turn the axle case (11) in the direction in which the
) rolling regulation mechanism (2) that prevents the rolling movement of the
A work vehicle equipped with 3A) and (23B).