JPH02234843A - Transmission for front-wheel of tractor - Google Patents

Abstract

PURPOSE:To eliminate quick deceleration of front wheels and have smooth transmitting operation by furnishing a front-wheel acceleration transmitting device, which is to make speed change to front-wheel transmitting speed into the accelerating zone when a tractor is turned by steering, with a changeover clutch which is to change over into the constant speed range due to drop of revolutions when the front-wheel accelerative transmitting is put into the neutral position. CONSTITUTION:In the body 5 of a tractor an engine 6 and a driver seat 8 are installed at the front and the rear, respectively. A front-wheel accelerative transmission 3 makes speed change of the front-wheel 2 transmitting speed into the accelerating zone with respect to the rear wheels 1 when the tractor is turned by steering. The front-wheel accelerative transmission 3 is equipped with a changeover clutch 4, which is to make changeover into constant speed range due to drop of revolutions when the accelerative transmitting to the front-wheels 2 is put into neutral position. Thus the front-wheel accelerative transmission 3 changes over the transmitting changed over into one-end accelerating zone into transmitting in the constant speed zone with the aid of a changeover clutch 4 upon awaiting the front wheels getting low revolutions. This eliminates abrupt deceleration of the front-wheels 2 and enables smooth transmitting operation.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to a front wheel transmission device for a tractor. Prior Art and Problems to be Solved by the Invention This invention improves turning performance by providing a speed-up transmission device that rotates the front wheels that are steered at a higher speed than the rear wheels when turning.
When the speed increasing transmission device is switched from the speed increasing position to the constant speed position due to the completion of a turn, etc., due to the inertial force of the tractor moving forward,
Sudden deceleration is likely to cause a WI strike.

Means for Solving the Problems This invention provides a front wheel speed increasing transmission device (3) that changes the transmission speed of the front wheels (2) to a speed increasing range with respect to the transmission speed of the rear wheels (11) during steering turns. A front wheel transmission device for a tractor is provided with a switching clutch (4) that switches the speed increasing transmission of the front wheel (2) to a constant speed range due to a decrease in rotation when the front wheel (2) is placed in a neutral position.

Functions and Effects of the Invention When turning by steering the front wheels (2) using the steering wheel, the front wheels (2) change from a constant speed transmission state to the rear wheels 11 and the front wheels to increase the speed of the front wheels. M(3) switching clutch《4
》, the power is transmitted to the speed increasing range and
The rear wheels (1) are rotated at a higher speed than the rear wheels (1), so that smooth steering and turning can be performed.

When this turning is completed, the switching clutch (4) temporarily becomes a neutral position in the increasing speed range transmission, and as the rotation of the front wheels (2) decreases, the transmission is switched to the constant speed range transmission.

In this way, the front wheel speed increasing transmission device (3) has a switching clutch (
4), the transmission once switched to the speed increasing range is transferred to the front wheels (
2) waits for the rotation to become low before switching to transmission in the constant velocity range, eliminating sudden deceleration of the front wheels (2) and providing smooth transmission. You can reduce the number of t7 hits. Embodiment In the illustrated example, the tractor body (5) is equipped with an engine (6) at the front, a front wheel (2) that can be steered by a control handle (7), and a driver's seat at the rear. (8)
It has a rear wheel (1) and has a four-wheel drive configuration. In the transmission case constituting the vehicle body (5), an input shaft (9) is interlocked from the engine (6) via a main clutch, and from this input shaft (9) main transmission 0 [and auxiliary transmission (iυ After that, transmission is configured from the rear differential device to the rear axle 0 of the rear wheels (1), and the front wheel speed increasing transmission (3) is
Through the front wheel clutch gear (b) that meshes with the take-out gear 03 of this sub-transmission if{1 (1), the transmission shaft 09, the transmission shaft Tl9 + the front wheel take-out shaft tr++, etc., the front wheel (2)
It is configured to transmit. The front wheel take-out shaft (■ is configured to transmit power to the front axle 0a of the front wheels (2) via the differential device.The transmission shaft (IQ is the transmission shaft between the transmission shaft 09 and the front wheel take-out shaft (m). A clutch is provided which is coaxial with the transmission shaft 11119 and moves in the axial direction against the spring (i) to directly disconnect the transmission from the transmission shaft 09.
A clutch shaft 4 equipped with a multi-disc switching clutch (4) is mounted in parallel with the clutch shaft 121).
Large and small speed increasing gears ■ (to) whose rotation is turned on and off by the switching clutch (4) are provided, and these speed increasing gears ■ are connected to the transmission shaft [one gear higher than the gear c! By meshing gear j with gear 4 on the transmission shaft 11e and turning on the switching clutch <<4>>, the transmission shaft Oe and the front wheel take-out shaft surface are aligned with the transmission shaft (approximately relative to +9). 6 This switching clutch (4) uses hydraulic pressure sent from the hydraulic circuit (to) to rotate the piston (to) in the cylinder (a).
The switching clutch (4) can be pressed forward (A) to connect and engage the transmission, and the on/off state of this switching clutch (4) is determined by the pressure control valve (To) provided in the hydraulic circuit. Controlled by the electronic control unit gf (CPU). The piston (to)
is provided with a pin (to), which engages the clutch (to), and by movement of this piston (to), a pin (to) is provided.
This clutch can be disengaged by moving the clutch to the front against the spring fFj.

The control device (CPU) includes a pressure sensor 0υ that detects the oil pressure of the hydraulic circuit (to), a front wheel sensor that detects the rotation of the front wheel (2), and a rear wheel sensor that detects the transmission rotation of the rear wheel (1). A transmission sensor (to) and a steering sensor (b) for detecting the operating angle of the steering handle (7) are provided for input, and the pressure is controlled by detecting a constant steering angle of the steering handle (7). The important control of speed increase is switching valve 4 to turn on and off the switching clutch (4), and the switching clutch (4) for this human-off control.
When the switch changes from on to off, the rear wheel transmission sensor (to)
The detected value of the rear wheel transmission is compared with the detected value of the front wheel rotation of the front wheel sensor (support), and the front wheel (2
) is the same or close to the rotation of the rear wheel +1), the switching clutch (4) is activated while controlling the pressure control valve (to).
While adjusting the engagement timing and engagement state of the clutch (to) due to disengagement, the constant velocity transmission is manually controlled so that sudden high-speed transmission is not performed to the front wheels (2). This sub-transmission sensor detects when the shifter (to) is operated to a high-speed position.
By detecting that (II) is in the high speed position, the pressure control valve (to) etc. are operated to prevent the switching clutch <<4>> from switching to the speed increasing range.

In addition, the front wheel sensor OD is connected to the gear shift shaft (formerly the front wheel <<2>>
It may be configured to detect the rotational speed of the transmission shaft, etc. up to this point, or it may be configured to detect the vehicle speed.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention; FIG. 1 is a partially sectional side view, FIG. 2 is a block diagram, and FIG. 3 is a partially cutaway side view.

Claims (1)

[Claims] During a steering turn, the front wheel (
Front wheel speed increasing transmission device (3) that changes the transmission speed of 2) to the speed increasing range
), there is a switching clutch (4) that switches to a constant speed range due to a decrease in rotation when the speed increasing transmission of this front wheel (2) is set to the neutral position.
) A front wheel transmission device for a tractor.