JP3339497B2 - Tractor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a front wheel speed-up control device for driving the peripheral speed of a front wheel higher than the peripheral speed of a rear wheel in conjunction with a turning operation of a vehicle body, and a rear wheel inside the turning. The present invention relates to a tractor provided with a braking device for braking, in which a driving mode of a wheel is selected by a simple operation according to working conditions, running conditions, and the like.

[0002]

2. Description of the Related Art Conventionally, a traveling drive mode of a tractor includes a four-wheel constant-speed drive mode in which a peripheral speed of a front wheel is substantially equal to a peripheral speed of a rear wheel, and It is configured to be switchable between a two-wheel drive mode in which the rear wheels do not drive the wheels and a front wheel speed-up drive mode in which the peripheral speed of the front wheels is driven at substantially double the peripheral speed of the rear wheels. As disclosed in Japanese Utility Model Laid-Open Publication No. 63-202523, there is known an apparatus that switches from the four-wheel constant-speed drive mode to the front-wheel speed-up drive mode when turning in a field.

However, in the field work using a tractor, it is necessary to appropriately switch the front wheel drive mode and the rotation state of the rear wheels at the time of turning according to the slip state and the weight balance between the front and rear of the vehicle. Since the lever for switching to the two-wheel drive mode or the four-wheel constant speed drive mode, the lever for turning on / off the front wheel speed increasing control device, and the on / off setting tool for brake control during turning are separately configured, The operator who is unfamiliar with this has a problem that a quick turning operation, for example, a lifting operation or a brake operation of a work machine is delayed or an erroneous operation is likely to occur.

When the individual levers are replaced with a single setting device, it is desirable that the individual levers are arranged at a set position where the driver can easily understand the driving state of the front wheels and the on / off state of the brake control during turning. .

[0005]

SUMMARY OF THE INVENTION In view of the above problems, according to the present invention, the power transmission state of the front wheels 1 is substantially the same as the non-drive state and the peripheral speed of the rear wheels 2. Clutch mechanisms 19 and 25 are provided to switch between a state of driving at the same speed and a state of driving at a speed higher than the peripheral speed of the rear wheel 2.
The clutch mechanism 19, 25 and the brake device 18, 18 are configured to be operable by an energized output of a controller, and the running state of the tractor is maintained by the switch 3 in the two-wheel drive state in both straight turning and turning. The four-wheel drive mode, in which the vehicle is driven at substantially the same speed as the peripheral speed of the rear wheel 2 for both straight driving and turning, and the state in which the vehicle is driven at substantially the same speed as the peripheral speed of the rear wheel 2 when driving straight Sometimes rear wheel 2
In the invention of claim 2, the tractor is switched by the switch 3 to switch to a state in which the tractor is driven at a speed higher than the peripheral speed and to sequentially switch to a "turning mode" in which the turning inside rear wheel 2 is braked. "Turning mode" from "2WD mode"
When switching to, the switching is always performed via the "four wheel drive mode".

[0006]

In the work by the tractor, the driving is generally switched to the two-wheel drive on a hard running surface and to the four-wheel drive on a soft running surface. Further, when the front wheel 1 is driven at a higher speed than the rear wheel 2 during turning to apply a brake to the rear wheel 2 on the inside of the turn, the slip is prevented on a soft running surface to make a small turn. Since it is intended to be able to be performed, if it is possible to switch in the order of "two-wheel drive mode", "four-wheel drive mode", and "turn mode" by operating the switch, each lever is operated as described above. There is no necessity, and the running mode can be quickly switched even when the working state changes. In addition, particularly in the case of the second aspect of the present invention, if it is configured to always switch to the "turning mode" via the "four-wheel drive mode" after the "two-wheel drive mode", the vehicle can travel straight ahead in the "turning mode". Is easily recognized as a four-wheel drive, and the inexperienced operator can easily understand the setting state of the tractor.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings. The tractor has an engine 5 mounted on the front part of the vehicle body 4 as shown in FIGS.
Front wheels 1, 1 steered by a steering handle 6 are mounted on the left and right sides of the engine 5, and a cockpit 7 and rear wheels 2, 2 are mounted on the rear of the vehicle body.
Is driven to drive the front wheel 1 or the rear wheel 2 via the transmission.

A clutch housing 8 connected to the rear of the engine 5 houses a main clutch 9, and the rotational power of the engine 5 is transmitted from the main clutch 9 to a transmission 12 of a rear transmission case 11 via a transmission shaft 10. You. The power take-out shaft 13 projects from the rear transmission case 11 to the rear to transmit a working device connected to the rear of the vehicle body. Also,
A rear wheel differential 15 is interlocked with the transmission 12 via a running shaft 14, and a rear wheel axle 17 having the rear wheel 2 is transmitted from the rear wheel differential 15 via left and right rear axles 16. still,
Reference numeral 18 in the drawing denotes a rear wheel brake that brakes the rear axle 16.

Further, the transmission clutch 12 to the precursor clutch 19,
And the front wheel differential device 21 is interlocked via the front drive shaft 20,
Further, from the front wheel differential device 21, left and right front wheel shafts 22 are provided.
And the like, the front wheel shaft 23 having the front wheel 1 and the like are transmitted. On the front wheels 22, a front wheel brake 24 for braking the rotation of the front axle 22, a front wheel clutch 25 for turning on / off the transmission from the front axle 22 to the front wheel axle 23, and the like are provided.

Each rear wheel brake 18, a precursor clutch 19,
Each of the front wheel brakes 24 and each of the front wheel clutches 25 are operated by hydraulic pressure, and each of the electromagnetic solenoid valves 26, 27, 28, 29, etc. is operated by an output command from a controller CPU having a microcomputer. It is activated by the switching operation of. Further, a steering angle sensor 30 for detecting the steering angle, that is, the steering direction, is provided on the rotation shaft of the steering handle 6. It is configured to switch between two-wheel drive turning by the rear wheels 2 with the driving off, or turning by front wheel speed-up control in which the peripheral speed of the front wheels 1 is increased to be greater than the peripheral speed of the rear wheels 2 and driven. .

A drive mode switch 3, which is a switching tool for selectively setting the turning mode, is provided, for example, on a dashboard 32 near the steering handle 6 and is pressed by a finger to push the drive mode switches A, B, C, and D. The position can be switched in stages, and this switching is repeated in a rotary form. That is, every time the switch 3 is pressed, the peripheral speed of the front wheel 1 is changed from the four wheel drive state to the rear wheel 2 only in the "two-wheel mode A" by the rear wheel 2 and the "four-wheel mode B" by the front and rear wheels only when turning. "Super full turn mode C (first turning mode)" in which the speed is increased to the peripheral speed of the vehicle, and "two-wheel drive mode D (second turning) in which the driving of the front wheels 1 is switched from the four-wheel drive state only during turning. Mode) in this order.
Each of the modes A to D selected by the drive mode switch 3 is digitally displayed or lit on a display unit provided on a part of the dashboard 32, and immediately after this display, the solenoid valve 2 corresponding to each mode is displayed.
It is preferable to provide a time delay device or a delay timer so as to output to 6 to 29. In this case, if the selected mode is incorrect, the driver can press the drive mode switch 3 again to select a desired mode after checking the display and confirming that the output section is not operated.

Next, the transmission configuration for each drive mode will be described. When the drive mode switch 3 is in the "four wheel drive mode B", the precursor clutch 19 is turned on,
The left and right front wheel clutches 29 are engaged. Therefore, the rotational power output from the transmission 12 is sequentially transmitted to the traveling shaft 14,
The rotational power output from the transmission 12 while being transmitted to the rear wheel differential 15, the left and right rear axles 16, and the rear axle 2 are sequentially transmitted to the precursor clutch 19, the front axle 20, the front wheel differential 21, the left and right The power is transmitted to the front axle 22 and the front wheel clutch 25, and the front wheel 1 is transmitted. Therefore, the tractor travels by four-wheel drive using the front wheels 1 and the rear wheels 2.

When the drive mode switch 3 is in the "two-wheel drive mode A", the precursor clutch 19 is disengaged by energizing the solenoid valve 27, and each front wheel clutch 25 is disengaged by energizing the left and right solenoid valves 29. Become. Accordingly, the rotational power output from the transmission 12 is sequentially transmitted to the traveling shaft 14, the rear wheel differential 15, the left and right rear axles 16
, The rear axle 2 is transmitted, and the front wheels 1 are not driven. Therefore, the tractor is mounted on the rear wheel 2
It travels by two-wheel drive.

When the drive mode switch 3 is in the "super full turn mode C", the tractor is normally in the "four wheel drive mode A" and the steering angle sensor 3
When the detected value of 0 detects a predetermined steering angle, for example, when the vehicle is turning leftward, the right solenoid valve 29
The right front wheel clutch 25 is disengaged and the right front wheel brake 24
And the peripheral speed of the front wheel 1 on the left turning side is
Due to the differential of the front wheel operating device 21, it is driven at twice the traveling speed, while the right front wheel 1 is in a free rotation state. The same applies to the right turn, and when these turns are completed, the vehicle returns to the four-wheel drive state.

When the drive mode switch 3 is in the "two-wheel turn mode D", when the detection value of the steering angle sensor 30 detects a predetermined steering angle, the precursor clutch 19 is disengaged and the left and right front wheel clutches 25 are turned off. Then, the vehicle is switched from the four-wheel drive state to the two-wheel drive state such as the "two-wheel drive mode A". In this case, when the turning is completed, the precursor clutch 19 and the left and right front wheel clutches 25 are engaged and return to the four-wheel drive state.

In the "super full turn mode C" and the "two-wheel turn mode D", the rear inner wheel brake 18 is operated by the output of the solenoid valve 26 in conjunction with the turning operation. . In the "two-wheel drive mode D", the left and right front wheel clutches 29 may be disengaged and the power transmission may be interrupted while the precursor clutch 19 is engaged.

In the operation using the tractor configured as described above, generally, the mode is switched to the "two-wheel drive mode" on a hard running surface and to the "four-wheel drive mode" on a soft running surface. Further, when the front wheel 1 is driven at a higher speed than the rear wheel 2 during turning to apply a brake to the rear wheel 2 on the inside of the turn, the slip is prevented on a soft running surface to make a small turn. As described above, the drive mode switch 3 can be used to sequentially switch between “two-wheel drive mode”, “four-wheel drive mode”, and “super full turn mode” as described above. There is no need to operate
The running mode can be quickly changed even when the working state changes. In this case, the "4WD mode" is always set after the "2WD mode" by the drive mode switch 3.
To switch to the "Super Full Turn Mode" via the, so it is easy to recognize that the vehicle is set to four-wheel drive when going straight in "Super Full Turn Mode". Is easy to understand.

[Brief description of the drawings]

FIG. 1 is a plan view showing a transmission mechanism of a tractor.

FIG. 2 is a control block diagram.

FIG. 3 is a flowchart.

FIG. 4 is an overall side view of the tractor.

[Explanation of symbols]

 Reference Signs List 1 front wheel 2 rear wheel 3 drive mode switch 19 precursor clutch 25 left (right) front wheel clutch

Claims (2)

(57) [Claims] 1. A power transmission state of a front wheel 1 is in a non-drive state, a state in which the front wheel 1 is driven at substantially the same speed as a peripheral speed of a rear wheel 2,
Clutches 19 and 25 are provided for switching to a state of driving at a speed higher than the peripheral speed of the rear wheels 2, and brake devices 18 and 18 are provided on the rear wheel 2 for braking independently of left and right. And the brake devices 18, 18 are configured to be operable by the power output of the controller.
"Two-wheel drive mode" in which the running state of the tractor is maintained in the two-wheel drive state by the switch 3 for both straight turning and "four-wheel drive mode" in which the traveling state of the tractor is driven at substantially the same speed as the peripheral speed of the rear wheel 2 for both straight turning. When the vehicle is traveling straight, the vehicle is driven at substantially the same speed as the peripheral speed of the rear wheel 2, and the vehicle is switched to a state in which the vehicle is driven at a speed higher than the peripheral speed of the rear wheel 2 at the time of turning. The tractor is configured to change in order. 2. The tractor according to claim 1, wherein when the tractor is switched from the “two-wheel drive mode” to the “turning mode” by the switch 3, the tractor is always switched via the “four-wheel drive mode”.