JP2002144903A - Tractor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the turning performance of a body by increasing the speed of front wheels smoothly without a shock and the like in a gear shift. SOLUTION: A tractor 1 comprises a front wheel speed increasing mechanism 24 for increasing the driving speed of front wheels 4. A speed increasing part of the speed increasing mechanism 24 comprises planetary gears 24a.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tractor which is equipped with an agricultural work machine such as a tilling work machine at a rear portion of a machine body to perform various agricultural works.

[0002]

Conventionally, in a front wheel speed increasing mechanism for increasing the driving speed of the front wheels, for example, two-stage gear switching of low speed and high speed is performed. In addition, it is difficult to smoothly increase the speed due to the impact of the tire, and there is a problem that the tires are abnormally worn due to the occurrence of a slip phenomenon on the wheels due to a constant speed increase ratio regardless of the steering angle of the steering wheel.

[0003]

SUMMARY OF THE INVENTION Accordingly, the present invention provides a tractor having a front wheel speed increasing mechanism for increasing the driving speed of a front wheel, wherein the speed increasing portion of the speed increasing mechanism is constituted by a planetary gear. It is intended to prevent inconveniences such as an impact at the time of increasing the speed, to facilitate a smooth increase in the speed of the front wheels, and to improve turning performance.

Further, an actuator is interlocked with a ring gear constituting a planetary gear, and the speed of the front wheel speed increasing mechanism is shifted by the actuator. The speed of the front wheel is easily and surely increased by the actuator, thereby increasing the steering wheel turning angle. In this case, the vehicle turns with good small turning performance.

Further, by controlling the speed increase ratio of the front wheel speed increasing mechanism in accordance with the turning angle of the steering wheel, the front wheels are driven at a speed appropriately corresponding to the turning radius, so that the grip of the front wheels with respect to the field is improved. To improve the turning performance.

Further, when the vehicle speed is high, the speed increase ratio of the front wheel speed-increasing mechanism is reduced to prevent high-speed abrupt turning and perform stable and favorable turning of the body at high speed with reduced front wheel tire wear and the like. is there.

In addition, the front wheel speed-up mechanism is controlled to increase according to the braking force when the left-right turning brake is actuated, so that the driving of the front wheels at the time of small turning with a small turning radius can be performed with less tire wear. Thus, the small turning property is improved.

[0008]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a side view of the whole, and FIG. 2 is a plan view of the same. In FIG. 1, (1) is a tractor, and an engine (2) is shown.
(3) Left and right front wheels (4) on both sides
(4), a round steering handle (5) is provided at the rear of the hood (3), and a driver's seat (6) is installed behind the handle (5). The left and right rear wheels (7) and (7) are installed on the vehicle, and the left and right brake pedals (9) and (9) and the clutch pedal (10) are arranged on the front step (8) of the driver's seat (6). Is seated on the driver's seat (6) and travels, and at the rear of the tractor
Rotary cultivator (1) via the point link mechanism (11)
2) is installed so as to be able to move up and down freely to perform tilling work.

In addition, a traveling main transmission lever (13) and an elevating lever (14) for elevating and lowering the work implement (12) are disposed on the right side of the driver's seat (6).
5) and a PTO shift lever (16) for shifting the output of the work implement (12) is disposed on the left side of the driver's seat (6).

As shown in FIG. 3, a power transmission mechanism (17) for the engine (2) includes a main clutch section (18) for disconnecting engine power, and a main and sub clutch for changing a power rotational speed according to a working state. The transmission units (19) and (20), the rear differential mechanism (21) that causes a differential phenomenon in rotation of the left and right rear wheels (7) and (7), and the left and right rear wheels (7) and (7) are each independently provided. Left and right turning brakes (22) and (23) for braking, and a front wheel speed increasing mechanism (2) for shifting the drive speed of the front wheels (4) and (4)
4) and the speed change output from the speed increasing mechanism (24) is transmitted to the propulsion shaft (2).
5) a front differential mechanism (26) for generating a differential phenomenon in the rotation of the left and right front wheels (4) and (4) by inputting through the front and rear wheels (4) (4). (7) The apparatus is configured to drive (7) to run and turn the body.

As shown in FIG. 4, the front wheel speed increasing mechanism (2)
4) is formed by a planetary gear (24a), one sun gear (27) at the center, three planetary gears (28) meshing on the outer periphery of the sun gear (27), and a ring gear meshing with these planetary gears (28). A planetary gear (24a) is formed by (29) and the like, and a sun gear (27) is connected to an output shaft (30) of the subtransmission unit (20), and a carrier shaft (31) coaxial with the output shaft (30). A planetary gear (28) is rotatably supported by the carrier (32).

The ring gear (29) has internal teeth (29a) meshing with the planetary gear (28) and external teeth (29b) formed on the outer periphery, and has a rotary shaft (3) of a hydraulic motor (33).
The speed increasing gear (35) attached to the front wheel (4) is meshed with the external teeth (29b), and the rotational speed of the carrier shaft (31) is increased by drive control of the hydraulic motor (33) to increase the front wheels (4) and (4). It is configured to increase the driving speed of.

As shown in FIG. 5, the hydraulic motor (3)
A motor control proportional valve (37) is interposed between the hydraulic pump (36) and the hydraulic pump (36) for supplying hydraulic pressure to the hydraulic pump (36), and includes a hydraulic switching valve (38), a pilot valve (39), and an unload valve (4).
0) to form a proportional valve (37), and to input a rotation control signal from a front wheel drive controller (42) to a solenoid (41) for operating the proportional valve (37) to control the rotation of the hydraulic motor (33). It is configured to control.

A steering gear (44) provided at the lower end of the handle shaft (43) of the steering handle (5) is connected to the steering shaft (4).
5) meshing with the sector gear (46), rotating the steering shaft (45) by a steering angle (handle angle) which is a steering angle operated by the steering handle (5); The rotation of the shaft (45) is detected by a potentiometer type steering wheel angle sensor (47).

The left and right brake devices (22)
(23) Left and right brake sensors (48) and (49) for detecting brake pressure during operation, a vehicle speed sensor (50) for detecting rotation of the output shaft (30) of the subtransmission unit (20),
The cutting angle sensor (47) is input-connected to the controller (42), and these sensors (47), (48), (4) are connected.
9) The drive control of the hydraulic motor (33) based on the detection of (50) (speed increase control of the front wheel (4)) is performed.

As shown in FIG. 6, the relationship between the steering wheel turning angle due to the operation of the steering wheel (5) and the front wheel speed increasing ratio is conventionally expressed by, for example, a constant turning angle (40 deg) as indicated by the D line. In contrast to the change from 1.0 to 2.0, in the case of this embodiment, the speed increase ratio is 1.0 to 2.0 with respect to the steering wheel turning angle.
Is set by an arbitrary curve (non-linear) line A, B or the like. In the case of line A, the speed increase ratio is reduced in a region where the steering wheel turning angle is small and the front wheel (4) and the rear wheel (7) In the case of the B-line, the vehicle turns with a large speed increase ratio in a region where the steering angle is small.

As shown in FIG. 6C, when the vehicle speed is higher than a certain speed, the front wheel (4) is subjected to speed increase control based on a proportional straight line having a small speed increase ratio, so that the steering wheel turning angle is large. Even in such a case, the speed increase of the front wheels (4) is suppressed to a small value, and the turning of the aircraft is stably maintained.

During the change control of the speed increase ratio based on the A, B, and C lines, when one of the left and right (inside the body) turning brake devices (22) and (23) is operated, the braking force is reduced. The speed increase ratio (a) set accordingly is increased by a fixed value (α) (a + α), and the front wheels (4) are increased as the braking force of the brake device (22) or (23) inside the fuselage increases. It is configured to speed up.

This embodiment is constructed as described above, and as shown in the flowchart of FIG.
7) The detected values of (48), (49), and (50) are input to the controller (42), the speed increasing ratio mode for the A, B, and C lines is set, and the in-working angle sensor (47) and the brake sensor (48) When the turning of the body is detected by (49), the front wheel (4) is accelerated to the speed increasing ratio (a) in the setting mode (A or B) according to the steering wheel turning angle. Also, at this time, when the left and right brake devices (22) and (23) are also operated, the front wheels (4) are accelerated to a speed at which the speed increase ratio (a + α) is increased by a constant value (α) corresponding to the braking force. The turning of the aircraft with a small turning radius is performed. Further, when the vehicle speed becomes higher than a certain value during such a turning operation, the front wheel (4) is increased in speed with a small increase ratio based on the mode of the C-line, so that the aircraft can rapidly turn at a high speed. Is to be prevented.

As is apparent from the above description, in the tractor (1) having the front wheel speed increasing mechanism (24) for increasing the driving speed of the front wheel (4), the speed increasing portion of the speed increasing mechanism (24) is provided. The planetary gear (24a) is used to prevent inconveniences such as an impact when the front wheel (4) is accelerated, and to easily enable stepless smooth acceleration of the front wheel (4), thereby turning. Performance can be improved.

A ring gear (29) constituting the planetary gear (24a) is connected to a hydraulic motor (3) as an actuator.
3), the front wheel speed increasing mechanism (24) is shifted by the hydraulic motor (33), and the front wheel (4) is easily and surely speeded up by the hydraulic motor (33). When the turning angle is large, it is possible to perform the turning of the aircraft with good small turning performance.

Further, the speed increasing ratio of the front wheel speed increasing mechanism (24) is controlled according to the turning angle of the steering handle (5).
By driving the front wheel (4) at a speed appropriately corresponding to the turning radius, it is possible to improve the grip performance of the front wheel (4) with respect to the field and improve the turning performance.

Further, when the vehicle speed is high, the speed increase ratio of the front wheel speed increasing mechanism (24) is reduced to prevent a sharp turn at a high speed and to reduce tire wear and the like of the front wheels (4), thereby achieving good stability at high speed. The aircraft can turn. Even at high speeds, when turning, increasing the speed slightly reduces tire wear.

Further, when the brake devices (22) and (23), which are left and right turning brakes, are operated, the front wheel speed increasing mechanism (24) is controlled to increase the speed in accordance with the braking force so that the turning radius is reduced. The driving of the front wheel (4) can be made favorable with little tire wear and the like, and the small turning property can be improved.

In the above embodiment, the front wheel speed increasing mechanism (2
Although the configuration in which the front wheel speed-up control is performed by the hydraulic motor (33) using the hydraulic motor (33) as the actuator of 4) has been described, as shown in FIGS.
A hydraulic continuously variable transmission (HST) (53) composed of a combination of 1) and a motor (52) may be used, and the speed increasing gear (35) is attached to an output shaft (54) of a hydraulic motor (52). A control arm (55) for controlling the rotation speed of the hydraulic motor (52) by adjusting the swash plate angle of the hydraulic pump (51).
A speed-up control member (56) such as a front wheel speed-up motor is interlocked and connected, and the speed-up control member (56) is driven by a rotation signal from the controller (42) to control the speed up of the front wheel (4). It is composed.

FIG. 9 shows a control arm (55) of a continuously variable transmission (53) interlockingly connected via a rod (58) to a steering arm (57) integrally connected to the sector gear (46). Thus, the use of the controller (42) is made unnecessary.

[0027]

As is apparent from the above embodiments, the present invention relates to a tractor (1) provided with a front wheel speed increasing mechanism (24) for increasing the driving speed of a front wheel (4). ) Is constituted by the planetary gears (24a), so that inconveniences such as impacts can be prevented when the front wheels (4) are accelerated, and the stepless smooth acceleration of the front wheels (4) is achieved. The turning performance can be improved by making it possible easily.

Further, an actuator (33) is interlockedly connected to a ring gear (29) constituting a planetary gear (24a), and the front wheel speed increasing mechanism (24) is shifted by the actuator (33). The speed of the front wheel (4) can be easily and surely increased by an actuator (33) such as a hydraulic motor, so that the turning of the body with good small turning performance can be performed when the steering wheel turning angle is large.

Further, since the speed increase ratio of the front wheel speed increasing mechanism (24) is controlled in accordance with the turning angle of the steering handle (5), the front wheels (4) at a speed appropriately corresponding to the turning radius.
, The grip performance of the front wheel (4) with respect to the field is improved, and the turning performance can be improved.

Further, since the speed increase ratio of the front wheel speed increasing mechanism (24) is reduced when the vehicle speed is high, high speed sudden turning is prevented to reduce tire wear and the like of the front wheels (4). This makes it possible to perform stable and stable aircraft turning.

The left and right turning brakes (22) and (23)
Since the speed-up control of the front wheel speed increasing mechanism (24) is performed in accordance with the braking force at the time of the operation of the wheel, the driving of the front wheel (4) at the time of a small turning with a small turning radius can be performed with good tire wear and the like. As a result, the small turning property can be improved.

[Brief description of the drawings]

FIG. 1 is an overall side view.

FIG. 2 is an overall plan view.

FIG. 3 is an explanatory diagram of a traveling drive system of the tractor.

FIG. 4 is an explanatory diagram of a front wheel speed increasing mechanism.

FIG. 5 is an explanatory diagram of a front wheel transmission mechanism.

FIG. 6 is a diagram showing a relationship between a steering wheel turning angle and a front wheel speed increasing ratio.

FIG. 7 is a flowchart.

FIG. 8 is an explanatory diagram using a continuously variable transmission for a front wheel speed increasing mechanism.

FIG. 9 is an explanatory diagram using a continuously variable transmission for a front wheel speed increasing mechanism.

[Explanation of symbols]

 (1) Tractor (4) Front wheel (5) Steering handle (22) (23) Brake device (slewing brake) (24) Front wheel speed-up mechanism (24a) Planetary gear (29) Ring gear (33) Hydraulic motor (actuator)

Continued on the front page F term (reference) 2B043 AA03 AB08 BA02 BB01 BB03 DB06 DB21 3D043 AA03 AB12 AB17 EA02 EA23 EA42 EB14 EE07 EE08 EE09 EE12 EF16 3D052 AA02 BB08 DD03 EE02 FF01 GG03 HH01JJ10

Claims (5)

[Claims] 1. A tractor having a front wheel speed increasing mechanism for increasing the driving speed of a front wheel, wherein the speed increasing portion of the speed increasing mechanism is constituted by a planetary gear. 2. The tractor according to claim 1, wherein an actuator is interlocked with a ring gear constituting the planetary gear, and the speed of the front wheel speed increasing mechanism is shifted by the actuator. 3. The tractor according to claim 1, wherein the speed increasing ratio of the front wheel speed increasing mechanism is controlled in accordance with the turning angle of the steering wheel. 4. The tractor according to claim 1, wherein the speed increasing ratio of the front wheel speed increasing mechanism is reduced when the vehicle speed is high. 5. The tractor according to claim 1, wherein the front wheel speed-up mechanism is controlled to increase the speed in response to the braking force when the left-right turning brake is actuated.