JP3235598B2 - 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 tractor provided with a front wheel speed-up control device for driving a peripheral speed of a front wheel higher than a peripheral speed of a rear wheel in conjunction with a turning operation of a vehicle body. It is intended to make it possible to select the driving mode of the wheels by a simple operation according to work 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.

[0003] However, in field work by a tractor, it is necessary to appropriately and appropriately switch the front wheel drive mode at the time of turning, depending on the slip state and the weight balance between the front and rear of the vehicle. Since the lever for switching to the form or the four-wheel constant-speed drive form and the lever for turning on and off the front wheel speed increasing control device are separately configured, the operator unfamiliar with the work can perform a quick turning operation,
For example, the lifting operation or brake operation of the work equipment is delayed,
There is a problem that erroneous operations are likely to occur.

In the case where the individual levers are replaced with a single setting device, it is desirable that the driving condition of the front wheels is easily understood by the driver, and that the arrangement is arranged at a set position where the shock is small at the time of each mode transition. .

[0005]

SUMMARY OF THE INVENTION In view of the above-mentioned problems, the present invention provides a power transmission state of the front wheels 1 in a non-driving state, a state in which the front wheels 1 are driven at substantially the same speed as the peripheral speed of the rear wheels 2, and a rear transmission state. Wheel 2
Clutch mechanisms 19 and 25 are provided for switching to a state in which the vehicle is driven at a speed higher than the peripheral speed of the vehicle. A tractor provided with a front wheel speed-up control device that drives the power transmission state of the front wheel 1 at a speed higher than the peripheral speed of the rear wheel 2 when the power output from the controller is performed. The setting device 3 that is set to be in an operable state is configured by a push-type switch, and the setting position is sequentially set by the pressing operation of the setting device 3, and the “two-wheel drive mode” position in which the driving of the front wheels 1 is sequentially disabled. A "four wheel drive mode" position in which the peripheral speed of the front wheel 1 is driven at substantially the same speed as the peripheral speed of the rear wheel 2; Activate When switching from the "front wheel speed-up mode" position to the "front wheel speed-up mode" position and switching to the "four wheel drive mode" position, the vehicle always passes through the "two wheel drive mode" position. A tractor.

[0006]

In the operation 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 vehicle is driven by increasing the peripheral speed of the front wheels 1 than the peripheral speed of the rear wheels 2 at the time of turning, it is intended to prevent a slip on a weak running surface and perform a small turning. The "2WD mode" position is followed by the "4WD mode" and the "Front wheel speed-up mode" position, which are switched in sequence by a series of pushing operations to respond quickly and easily to changes in work conditions. be able to. When switching from the "front wheel speed-up mode" position to the "four wheel drive mode" position, the vehicle always goes through the "two-wheel drive mode" position. Since the power transmission to the front wheels 1 is temporarily cut off, a shock due to the deceleration of the front wheels 1 can be prevented as compared with the configuration in which the positions can be directly switched to the positions. Still further, in order to switch to the "four wheel drive mode" position, the situation in which the driver accidentally touches the setting device 3 unexpectedly and falls into the deceleration shock state because of at least two pushing operations is required. It can be prevented as much as possible.

[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 drive mode A" with the rear wheels 2 and the "four-wheel mode B" with the front and rear wheels. "Super-Full Turn (Front Wheel Acceleration Control) Mode C", which switches to increase the speed relative to the peripheral speed of the vehicle, and "Two-wheel Drive Turn Mode D," in which the drive of the front wheels 1 is switched off from the four-wheel drive state only when turning. Configuration. Each of the modes A to D selected by the drive mode switch 3 is digitally displayed or lit on a display unit provided in a part of the dashboard 32, and immediately after this display, the solenoid valves 26 to It is preferable to provide a time delay device or a delay timer so as to output the signal to the timer 29.
In this case, when the selected mode is incorrect, the driver can press the drive mode switch 3 again to select the 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 device 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 device 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 pre-clutch 19 is disengaged by energizing the solenoid valve 27, and the 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, the front wheel 1 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 brake 18 on the inside of the turn is operated by the output of the solenoid valve 26 in conjunction with the turn operation. good. 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 by the tractor constructed as described above, the mode is switched to "two-wheel drive mode A" on a hard running surface and to "four wheel drive mode B" on a soft running surface. Further, when the vehicle is driven with the peripheral speed of the front wheel 1 being higher than the peripheral speed of the rear wheel 2 at the time of turning, slipping on a weak running surface is prevented to make a small turn. By arranging the position of the “super full turn mode C” next to the position “B”, it is possible to quickly and easily respond to a change in the working state, and to perform the setting switching with less erroneous operation.

[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 (1)

(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,
Clutch mechanisms 19 and 25 are provided for switching to a state in which the vehicle is driven at a speed higher than the peripheral speed of the vehicle. A tractor provided with a front wheel speed-up control device that drives the power transmission state of the front wheel 1 at a speed higher than the peripheral speed of the rear wheel 2 when the power output from the controller is performed. The setting device 3 that is set to be in an operable state is configured by a push-type switch, and the setting position is sequentially set by the pressing operation of the setting device 3, and the “two-wheel drive mode” position in which the driving of the front wheels 1 is sequentially disabled. A "four wheel drive mode" position in which the peripheral speed of the front wheel 1 is driven at substantially the same speed as the peripheral speed of the rear wheel 2; Activate "Front wheel acceleration mode" position and switched, from the "front wheel acceleration mode" position "four-wheel drive
When switching to the “mode” position, be sure to
Tractor, characterized in that a configuration you through the ejection mode "position.