JPH09132159A - Steering device for tractor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily perform a line conforming steering at backward turning back in a tractor work. SOLUTION: In a tractor in which steering interlocking motion of front wheels or rear wheels by operation of a steering handle can change between respective steering modes, i.e., a front wheel steering mode FWS, a rear wheel steering mode RWS, and a front and rear wheel steering mode 4WS, after the lapse of a fixed time T on a steering neutral position in the front and rear wheel steering mode 4WS and at operating backward shift R, the mode is automatically changed to the rear wheel steering mode RWS.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a steering device for a tractor, and it is intended to restrain an automatic steering mode when adjusting a rearward steering at a ridge.

[0002]

2. Description of the Related Art In a tractor management work machine that performs work while traveling along a ridge in a field, work is continued with the tractor work machine switched from the forward travel end to the reverse travel. There is a case. A tractor that performs such work enables steering in either the front wheel or rear wheel steering mode, and this steering mode switching is performed at the neutral position of the steering (when the wheels are in the straight traveling state). ), It is difficult to perform the alignment work.

For example, the forward working process is performed in the front wheel steering mode, and at the end of the ridge, the front and rear wheel steering mode is automatically switched to perform alignment, and after this alignment, the reverse working process is performed. In the steering system of the tractor that operates in the wheel steering mode, in the front and rear wheel steering mode strokes at the ridge, the wheels may once return to the straight state, which is the neutral position, during the alignment due to the steering wheel turning operation. As a result, the front / rear wheel steering mode is automatically switched to the rear wheel steering mode, which makes it difficult to perform alignment.

The present invention seeks to eliminate such defects.

[0005]

According to the present invention, the steering interlocking operation of the front wheels 2 or the rear wheels 3 by the operation of the steering wheel 1 is performed in a front wheel steering mode FWS and a rear wheel steering mode RW.
In a tractor capable of switching between the steering modes S and the front / rear wheel steering mode 4WS, the tractor is automatically operated by the elapse of a predetermined time T at the steering neutral position in the front / rear wheel steering mode 4WS and the reverse gear R operation. The steering device is configured to switch to the rear wheel steering mode RWS.

[0006]

[Advantages of the Invention and Effect of the Invention] The steering operation by the backward movement at the ridge or the like is in the operation of the reverse speed change R in the front / rear wheel steering mode 4WS, but the steering operation by the steering wheel 1 is performed during the adjustment. The steering neutral position may be temporarily turned by turning or the like, but if the state of the steering neutral position does not elapse for a predetermined time T, the front and rear wheel steering mode 4WS is maintained as it is and the predetermined time T elapses. Automatically switches to the rear wheel steering mode RWS.

As described above, in the steering operation during the backward running of the tractor, the front-rear wheel steering mode 4WS is maintained and controlled regardless of the turning steering operation of the steering wheel 1. The configuration can be simplified because the control can be performed accurately, and the restraint control is performed according to the time of the rear wheel steering mode RWS.

[0008]

EXAMPLE A tractor vehicle body 4 has a clutch housing 5, a transmission case 6 and the like connected to a rear side of an engine E, and a final case extending downward at left and right ends of a front axle housing 7 at a lower front portion of the engine E. 8 are connected to each other, the front wheel 2 which can be steered is axially mounted on the lower end,
A final case 10 extending downward is connected to the left and right ends of the rear axle housing 9 at the rear of the transmission case 6, and a steerable rear wheel 3 is axially mounted at the lower end. These front and rear wheels 2, 3 are Power steering hydraulic circuit 11 composed of an orbit roll by steering operation of steering handle 1.
Is steered through.

Reference numeral 12 is a cockpit, and 13 is a mission case 6.
A lift arm that is rotated up and down by hydraulic pressure above the upper part of the vehicle, connects the lower link 15 with the lift rod 14, and raises and lowers the working machine 17 connected with the three-point link mechanism such as the lower link 15 and the top link 16. To do. Reference numeral 18 denotes an interlocking shaft that connects between the PTO shaft 19 on the mission case 6 side and the input shaft 20 of the working machine 17. The working machine 17 constitutes a cultivator, a crushed soil in which the crushed soil claws 21 are arranged, and a weeding rotor. The work machine 17 manages crops while advancing along the left and right ridges.

The transmission of the tractor includes the engine E, the main clutch 22, the reversal clutch 23, and the main transmission 2.
4, and the rear wheel diff device 26 and the front wheel diff device 27 through the auxiliary transmission 25, the rear wheel diff device 26 and the rear wheel 3 from the rear wheel diff device 26, and the front wheel 2 from the front wheel diff device 27. Work together. Among these, a speed increasing device 28 is provided in the middle of the transmission path to the front wheel differential device 27, and when the speed increasing device 28 is operated to the neutral position, transmission to the front wheel differential device 27 is not performed and only the rear wheel 3 is transmitted. Rear two-wheel drive driving (R2
WS), and when the speed increasing device 28 is operated to the normal 4WD position, the front wheels 2 are transmitted at substantially the same speed as the rear wheels 3 and the normal four-wheel drive traveling (4WD) is performed. When the vehicle is operated to the double speed 4WD position, the front wheels 2 are transmitted at a speed almost double that of the rear wheels 3 to drive the double speed four-wheel drive (double speed 4W).
D) and the steering turning performance can be improved.

Further, from the main clutch 22, the PTO clutch 29, the PTO transmission 30 and the like are passed, and the PTO shaft 1
Interlock 9. The power steering hydraulic circuit 11 hydraulically operates the front and rear wheel steering cylinders 31 and 32 to perform steering interlocking, and includes double-acting pistons 33 and 34 and a steering arm 3.
5, 36, tie rods 37, 38, and the like. The front and rear steering cylinders 31, 32 are provided on the corresponding axle housings 7, 9 to the vehicle body 4. By steering the steering wheel 1, the power steering hydraulic circuit 1
The amount of oil corresponding to the steering angle by 1 is flown, and the front and rear wheel steering cylinders 31, 32 are operated by this hydraulic pressure. P
Is a hydraulic pump, 39 is a tank port, and 40 is a relief valve. The operation of the front / rear wheel steering cylinders 31, 32 is controlled by the operation of the front / rear solenoid valves 41, 42.

On the input side of the controller CPU having a microcomputer, there is provided a changeover switch 43 for manually changing the steering mode between the front wheel steering mode FWS, the rear wheel steering mode RWS and the front and rear wheel steering mode 4WS. Further, an automatic mode switch 44 for automatically switching each of these steering modes under certain conditions is provided. Besides this, a steering sensor 4 for detecting the steering angle of the steering wheel 1
5, front / rear wheel steering sensor 4 for detecting steering angles of front / rear wheels
6, 47, a lift arm sensor 48 for detecting the ascending / descending angle of the lift arm 13, and a reverser sensor 49 for detecting the transmission state of forward / reverse traveling are provided.

Further, front and rear solenoid valves 41 and 42 are provided on the output side of the controller CPU so that the front wheels can be operated in accordance with the steering mode selected by the steering mode changeover switch 43 or the automatic mode switch 44. In the steering mode FWS, the front solenoid valve 41 is output, and the rear wheel steering mode R is output.
In the WS, the rear solenoid valve 42 is output, and in the front / rear wheel steering mode 4WS, the front / rear solenoid valves 41, 42 are simultaneously output to perform power steering based on the steering wheel 1 steering. Further, it is configured to output the lowering / lowering solenoid valves 50 and 51 of the lift cylinder hydraulic circuit for raising and lowering the lift arm 13.

When the automatic mode switch 44 is turned on, at the end of the tractor work forward movement F stroke (headland at the edge of the ridge) A, steering is performed in the front wheel steering mode FWS.
When the steering angle by the steering sensor 45 becomes a certain angle or more, B, the lift arm 13 is automatically raised,
When the lift arm sensor 48 that detects the lift angle of the lift arm 13 detects a constant angle, the front wheel steering mode FWS is automatically switched to the front and rear wheel steering mode 4WS.

In this state, when the vehicle body 4 moves forward to reach the folded-back end portion C, the reverser clutch 23 is switched to the reverse gear shift position R, and the vehicle is steered so as to follow the work ridge D in the next stroke while moving backward. However, at this time, since the steering wheel 1 is turned back, the front wheel steering sensor 46 and the rear wheel steering sensor 47 are both in the neutral position (example ± 2 °) in the entry stroke G entering the work ridge D. That is, it may show a substantially straight traveling state. When the state of the steering neutral position exceeds a certain time T (for example, T = 3 seconds), the front / rear wheel steering mode 4WS is set.
Changes to the rear wheel steering mode RWS, but during a short time within the fixed time T, the front and rear wheel steering mode 4WS does not change.

In this way, the front and rear wheel steering mode 4WS
When the vehicle body 4 starts to travel along the reverse work ridge D, the predetermined time T has elapsed, and therefore, the rear wheel steering mode RWS is automatically switched to. Thus, the front and rear wheel steering mode 4WS is maintained until the alignment is completed, and the alignment steering is easily performed. In FIG. 6, the difference from the above example is that a constant vehicle speed V (eg 3 km
In the low-speed range reaching 4 / h), the front / rear wheel steering mode 4WS is maintained as it is to facilitate steering, and in the high-speed range of a certain vehicle speed V or higher, the front / rear wheel steering mode 4WS to the rear wheel steering mode RWS. It is designed to automatically switch to.

In the illustrated example, a hydraulic continuously variable transmission HST is used in place of the main transmission 24 and the reverser clutch 23, and corresponds to the constant vehicle speed V position of the reverse side gear shift of the trunnion shaft 52 for performing this continuously variable shift control. The trunnion arm 53, which is integral with the trunnion shaft 52, allows the continuously variable transmission to
A limit switch 54 that is operated N is provided, and when the limit switch 54 is turned on, the reverse high speed range is detected,
The front / rear wheel steering mode 4WS is switched to the rear wheel steering mode RWS to the rear wheel steering mode RWS.

An input shaft 55 of the hydraulic continuously variable transmission HST is interlocked with from the main clutch 22 side. The output shaft 56 is linked to the auxiliary transmission 25. In this hydraulic continuously variable transmission HST, the operation lever 57 is pivoted from the neutral position to the front side to pivot the trunnion shaft 52 to the arrow F1 side via the link mechanism 58 to output the output shaft 56.
Is normally rotated (forward side), and is sequentially transmitted to the high speed range according to the operation angle of the operation lever 57. Further, by rotating the operation lever 57 from the neutral position to the rear side, the trunnion shaft 52 is rotated to the arrow R1 side contrary to the above, and the output shaft 56 is rotated in the reverse direction (reverse side) to sequentially increase the speed. Transmitted to the area. or,
By depressing these operation levers 57 from the respective high speed regions to the neutral position side, the speed is reduced, and the traveling transmission is stopped at the neutral position.

Reference numeral 59 denotes a neutral urging arm which has a V-shaped cam edge 60 and applies tension to the roller 61 of the trunnion arm 53 by a spring 62 to urge the trunnion arm 53 to the neutral position N side. ing. A tentacle 63 is provided at the base of the trunnion arm 53, and the tentacle 63 turns on and off the limit switch 54 attached to the case of the hydraulic continuously variable transmission HST. The distance between the contact 63 and the limit switch 54 may be adjustable.

7 and 8 are different from the above example in that
When spraying a chemical liquid or the like by the tractor body 4 capable of steering the front and rear wheels 4WS, a semi-circular turn is made when the vehicle is turned around at the edge of the ridge, and therefore the spray boom 64 provided on the body 4 is provided. The lengths of 65 and 66 are automatically adjusted in accordance with the turning, and sprayed to the corners of the turning field scene H.

The boom 64 is fixed to the hitch 67 at the front end of the vehicle body 4 in the left-right direction, the side booms 65 are connected to the left and right ends of the fixed boom 64, and the movement is adjusted along the side boom 65. A telescopic boom 66 is provided.
This telescopic boom 66 is connected to the side boom 65,
The telescopic boom 6 may be configured to supply a chemical solution.
It is also possible to have a configuration in which only 6 is independently supplied with a chemical solution by hose connection or the like. The telescopic boom 66 may be moved by winding a wire or the like by driving a motor provided on the vehicle body side.

Nozzles facing downward are arranged on each of the booms 64-66, and a chemical solution can be sprayed downward. This chemical liquid is sent from a tank 68 on the vehicle body 4 side by a pump.
The vehicle has a turning sensor that detects the steering turning angle of the vehicle body 4 based on the steering angle of the steering handle 1, and the motor that drives the boom 66 to extend and retract according to the detection angle of the turning sensor is controlled to drive through the controller. The boom 66 is made to project for a long time in the portions corresponding to the farm field corners S1 and S2, and the corners serve as the spray area.

As shown in FIG. 8, if the tractor swivels 180 degrees in a circular locus during the turning swivel stroke, assuming that the normal spray width is up to the tip of the side boom 65, the swivel start position K1 After passing through the position K2 of the corner S1 of approximately 45 degrees, the position reaches the edge position K3 of 90 degrees, and further from this, the position K4 of the corner S2 of 45 degrees reaches the turning end position K5.
By turning as a length range of the side boom 65 at the edge position K3, it is sufficient to extend the telescopic boom 66 to the most distal end at the corners S1 and S2, between these K1 → K2 and between K3 → K4. Then, the telescopic boom 66 is extended according to the turning angle,
On the contrary, it is controlled so as to be sequentially shortened between K2 → K3 and between K4 → K5.

Such boom extension / contraction control can be used not only for the spraying device but also for a dusting device, a fertilizer applying device, a sowing device and the like.

[Brief description of the drawings]

FIG. 1 is a plan view showing a tractor work.

FIG. 2 is a power steering hydraulic circuit diagram.

FIG. 3 is a steering mode control block diagram.

FIG. 4 is a block diagram of a power transmission system.

FIG. 5 is a side view of the tractor.

FIG. 6 is a side view of a hydraulic continuously variable transmission operating mechanism part showing another embodiment.

FIG. 7 is a perspective view of a tractor management work machine showing another embodiment.

FIG. 8 is a plan view showing the work.

[Explanation of symbols]

 1 Steering handle 2 Front wheel 3 Rear wheel FWS Front wheel steering mode RWS Rear wheel steering mode 4WS Front and rear wheel steering mode R Reverse gear shift T Fixed time

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Masato Nagai No. 1 Hachikura, Tobe Town, Iyo-gun, Ehime Prefecture, Engineering Department, Iseki Agricultural Machinery Co., Ltd. Department

Claims (1)

[Claims] 1. A front wheel steering mode FW is a steering interlocking operation of front wheels 2 or rear wheels 3 by operating a steering wheel 1.
S, rear wheel steering mode RWS, front and rear wheel steering mode 4W
In the tractor that can switch between each steering mode with S,
A steering device that automatically switches to a rear wheel steering mode RWS in a front and rear wheel steering mode 4WS and when a predetermined time T elapses at a steering neutral position during a reverse gear shift R operation.