JPH09104249A - Turning control device of tractor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a device from being switched to a high speed condition even if a steering wheel is suddenly steered by arranging a connection detector to prevent a high-low speed switching device from being switched to a high speed condition by detecting connection of a pair of left and right brake pedals. SOLUTION: A connection detector 38 detects connection of a pair of left and right brake pedals 36. That is, a pair of left and right brake pedals 36 are pivoted in a suspended shape by a support shaft on the measuring instrument panel, and are energized in the returning direction by a tension spring. Cylinder bodies 43 are respectively fixed to pedal plates 42 of these respective brake pedals 36, and a connecting pin 44 is inserted into its one cylinder body 43 so as to be freely inserted into and extracted from the other cylinder body 43. Therefore, when a pair of left and right brake pedals 36 are connected to each other by this connecting pin 44, braking operation can be simultaneously performed on left and right rear wheel brakes by both pedals 36, and when connection is released, the braking operation can be independently performed on the left and right rear wheel brakes by a pair of left and right brake pedals 36. Therefore, a device can be prevented from being switched to a high speed condition.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a turning control device for a tractor.

[0002]

2. Description of the Related Art In a four-wheel drive tractor for driving front wheels and rear wheels, a high-low speed switching device is provided in a front-wheel drive system, and a high-low speed switching device is operated when a turning detection device interlocking with a steering system detects turning. The device is switched from low speed to high speed, and from the normal running state in which the front and rear wheels are synchronized (low speed state), the peripheral speed of the front wheels is increased to about twice the peripheral speed of the rear wheels (high speed state) to make a sharp turn in a small radius. There are things that I was able to do.

Such a turning control is used only when traveling at a low speed, such as when working in a field, and is not used when traveling at a high speed such as a road. Therefore, conventionally, a release switch is provided in the control circuit, and when the vehicle travels at high speed, the release switch is operated to turn off the turning control.

[0004]

However, in the past, the operator had to simply turn off the release switch, and the operator manually turned it off during high-speed traveling. Therefore, an object of the present invention is to control turning control without using a conventional release switch. In other words, it is an object of the present invention to provide a turning control device for a tractor, which focuses on connecting a pair of left and right brake pedals when traveling on a road and uses this connection detection for turning control.

[0005]

In order to achieve the above object, the present invention takes the following measures. That is, the feature of the present invention is that the turning detector that interlocks with the steering system and the low speed state in which the peripheral speed of the front wheels is substantially the same as the peripheral speed of the rear wheels and the turning detector that interlocks with the turning detector during turning. A tractor having a high / low speed switching device for switching the peripheral speed of the front wheels to a high speed state in which the peripheral speed of the rear wheels is set higher than that of the rear wheels, and a pair of left and right brake pedals for operating left and right rear wheel brakes is detachably connectable. The connection detector is provided to detect the connection of the pair of left and right brake pedals and prevent the high / low speed switching device from switching to the high speed state.

According to the present invention, since the pair of left and right brake pedals are connected to each other when the vehicle is traveling on the road, it is possible to prevent the high / low speed switching device from switching to the high speed state by detecting this connection by the connection detector. . Therefore, when driving on the road,
Even if you suddenly turn the steering wheel, you will not be in a high speed state.
Further, by providing a high speed detector for detecting the traveling speed and preventing the high / low speed switching device from switching to the high speed state at the time of high speed traveling, a safety means in case of forgetting to connect the brake is provided. Become.

It is preferable that the rear wheel is connected to the left and right differential yoke shafts of the rear wheel differential device, and the high speed detector detects the number of rotations of the left and right differential yoke shafts.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below with reference to the illustrated embodiment. In FIG.
The vehicle body 1 includes an engine 2, a clutch housing 3, a transmission case 4 and the like. 5 is a bonnet, 6 is a steering wheel, 7 is a driver's seat, and 8 is a hydraulic system for lifting the working machine. Reference numeral 9 denotes a pair of left and right front wheels, which are supported at both left and right ends of a front axle case 10 suspended on the front part of the tractor body 1, and are capable of steering operation in conjunction with a steering system including a handle 6 and the like. 11 is a pair of left and right rear wheels, 35 is a cabin, 36
Is a pair of left and right brake pedals.

FIG. 1 shows a traveling power transmission system and its control system. Reference numeral 12 is a main clutch, 13 is a main transmission, 12a is an auxiliary transmission, and 14 is a rear wheel differential device. Power is applied from the rear wheel differential device 14 to the left and right rear wheels 11 via the left and right final reduction gears 15. Transmitted. The rear wheels 11 are controlled by the rear wheel brakes 37. 16 is a gear mechanism of the front wheel drive system 17, and this gear mechanism
Power is transmitted from 16 to the left and right front wheels 9 via the transmission shaft 18, the high / low speed switching device 19, the propeller shaft 20, and the front wheel differential device 21.

The high / low speed switching device 19 includes a low speed transmission system for directly connecting the transmission shaft 18 and the propeller shaft 20 via a low speed hydraulic clutch 21 at a transmission ratio of 1: 1, a high speed hydraulic clutch 22 and a gear train 2.
3. A high-speed transmission system for interlocking and connecting the transmission shaft 18 and the propeller shaft 20 at a transmission ratio of 1: 2 via the intermediate shaft 24 and the gear train 25. The hydraulic clutches 21 and 22 are friction type, and when the both hydraulic clutches 21 and 22 are disengaged, the front wheels 9 are in an idle state and the rear wheels 11 drive two wheels.When the low speed hydraulic clutch 21 is engaged, the front wheels 9 are rear wheels 11. When the high speed hydraulic clutch 22 is engaged, a four-wheel drive that rotates at peripheral speeds that are substantially in synchronization with each other is configured so that the front wheel 9 turns at a double speed that rotates at about twice the peripheral speed of the rear wheel 11.

Reference numeral 26 is an electromagnetic valve that controls switching of the hydraulic clutches 21 and 22, and reference numeral 27 is a control circuit that drives the electromagnetic valve 26. 28
Is a turning detector, and the front wheels are linked to the operation of the steering system.
It is configured to turn on when the cutting angle of 9 becomes about 35 ° or 45 °. The turning detector 28 may directly detect the turning of the handle 6 or the turning of the front wheel 9 around the kingpin, and the mounting portion is not particularly limited as long as the turning operation can be detected.

Reference numeral 29 denotes a high speed detector, which is provided so as to detect the high speed running in advance by detecting the highest speed stage of the main transmission 13, as shown in FIG. That is, the main transmission device 13 is configured to change the meshing of a large number of transmission gear groups 34 by the main transmission lever 31 supported by the transmission base 30 via the shift fork 33 fixed to the shift rod 32. On the other hand, the high-speed detector 29 operates when the main shift lever 31 is operated to the highest speed, and the shift fork 33
Is mounted inside the mission case 13 so as to detect and turn on.

Reference numeral 38 denotes a connection detector for detecting the connection of the pair of left and right brake pedals 36, which is mounted as shown in FIGS. That is, as shown in FIGS. 4 and 5, the pair of left and right brake pedals 36 are pivotally supported in a suspended manner by the support shaft 40 on the instrument panel 39 side, and are biased in the returning direction by the tension spring 41. The pedal plate 42 of each brake pedal 36 has a cylindrical body.
43 are fixed respectively, and the connecting pin 44 is inserted into the one cylindrical body 43 so that it can be inserted into and removed from the other cylindrical body 43. Therefore, by connecting the pair of left and right brake pedals 36 with the connecting pin 44, the left and right rear wheel brakes 37 can be simultaneously braked by both pedals 36, and if the connection is released,
Left and right rear wheel brakes with a pair of left and right brake pedals 36
The 37 can be braked independently. The connecting pin 44 has a bent portion 45, and the bent portion 45 can be locked at the release position at one end of the guide groove 47 of the guide plate 46.

Reference numeral 48 is a tension spring. Coupling detector 38
Is attached to the pedal plate 42 on the side opposite to the connecting pin 44, and when the pair of left and right brake pedals 36 are connected by the connecting pin 44, the brake pin is operated and turned on. The control circuit 27 connects the low speed hydraulic clutch 21 when the turning detector 28 is off, and connects the low speed hydraulic clutch 21 when the turn detector 28 is on.
Solenoid valve so that the high speed hydraulic clutch 22 is engaged
26 is configured to operate, when the connection detector 38 is turned on, and when the high speed detector 29 is turned on, the low speed hydraulic clutch 21 is kept connected even when the turning detector 28 is turned on, Low speed hydraulic clutch 21 to high speed hydraulic clutch
It is configured not to switch to 22.

The control circuit 27 is provided with a release switch for preventing the solenoid valve 26 from operating when the turning detector 28 is turned on. At the time of working in the field, the pair of left and right brake pedals 36 are disconnected by the connecting pin 44, and the main transmission 13 is put in a position other than the highest speed stage to run at a low speed. Therefore, the connection detector 38 and the high speed detector are connected. 29 remains off and the control circuit 27 works as before. That is, when the handle 6 is operated to make a sharp turn at the end of the field, and the turn detector 28 is turned on when the front wheel 9 reaches a predetermined turning angle, the control circuit 27 operates and the solenoid valve 26 is moved from the low speed side to the high speed side. Switch. Therefore, since the low speed hydraulic clutch 21 is disengaged and the high speed hydraulic clutch 22 is engaged, the high / low speed switching device 19 switches from low speed to high speed, the front wheels 9 rotate at about twice the peripheral speed of the rear wheels 11, and the tractor operates. It can swivel quickly with a small radius.

Next, when traveling at high speed on the road due to movement in the field, the pair of left and right brake pedals 36 are connected by the connecting pin 44, and even when one of the brake pedals 36 is depressed, it is inevitable. The left and right rear wheel brakes 37 simultaneously brake the rear wheels 11. At this time, the connecting pin 44 connects the detector
38 is turned on, and the control circuit 27 shuts off the signal from the turning detector 28. Therefore, the high / low speed switching device 19 remains in the low speed state even during turning, and the tractor can safely turn in the normal four-wheel drive in which the front and rear wheels 9 and 11 rotate at the peripheral speed substantially synchronized.

On the other hand, when the vehicle is traveling on the road, the main transmission lever
31 is operated to put the main transmission device 13 into the highest speed stage. At this time, the shift rod 32 and the shift fork 33 move in the direction of arrow a in FIG. The control circuit 27 shuts off the signal from the turning detector 28. Therefore, even if the brake pedal 36 is forgotten to be connected, normal four-wheel drive can be used for turning.

In the case of FIG. 3, a limit switch or the like is used as the high-speed detector 29, but the present invention is not limited to this, and the following modifications are possible. That is, the high speed detector 29
It is also possible to use a laser beam type and attach it to the tractor body 1 so as to emit a laser beam toward the ground as shown by the phantom line in FIG. 2 so as to detect the actual traveling speed of the tractor.

Further, as the high speed detector 29, a rotation speed detecting type for detecting the rotation speed by voltage or the like is used to detect the rotation speed of the differential yoke shaft 49 of the rear wheel differential device 14 as shown in FIG. You can Of course, this can also be provided on the yoke shaft of the front wheel differential device 14. Further, when the high-speed detector 29 of the rotation speed detection type is used, as shown in FIG. 7, it is provided on each of the pair of left and right differential yoke shafts 49, and the detection values of both are averaged and corrected by the averaging circuit 50. You may do it. By doing so, it is possible to correct when either the left or right rear wheel 11 slips, and reliability is improved.

The connection detector 38, as shown in FIG.
A bush that supports the boss 51 of the brake pedal 36 on the 40
52 may be made of an insulating material such as resin, and when the pair of left and right brake pedals 36 are connected by the connecting pin 44, the two pedals 36 may be electrically connected. The connection detector 38 and the high speed detector 29 can be used in combination with any of them.

[0021]

According to the present invention, since the high / low speed switching device is maintained in the low speed state by detecting the connection of the pair of left and right brake pedals, the high speed state is inadvertently turned on even when the steering wheel is largely turned when traveling on the road. There is no such thing. Further, by providing the high speed detector, it is possible to cover the forgetting to connect the brake pedal. Further, by making the high speed detector detect the number of rotations of the left and right wheels, it can be used for other control such as slip control.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a main part showing an embodiment of the present invention.

FIG. 2 is a side view of the tractor.

FIG. 3 is a cross-sectional view of the high speed detection unit.

FIG. 4 is a side view of the brake pedal portion.

5 is an enlarged view taken along the line VV of FIG.

FIG. 6 is a configuration diagram showing another embodiment of the present invention.

FIG. 7 is a configuration diagram showing another embodiment of the present invention.

FIG. 8 is an exploded perspective view of the brake pedal.

[Explanation of symbols]

 9 front wheel 11 rear wheel 14 rear wheel diff device 19 high / low speed switching device 28 turning detector 29 high speed detector 36 brake pedal 37 rear wheel brake 38 connection detector 49 diff yoke shaft

Claims (3)

[Claims] 1. A turning detector (28) interlocking with a steering system, and a turning detector (28) at the time of turning in a low speed state in which a peripheral speed of a front wheel (9) is substantially equal to a peripheral speed of a rear wheel (11). It is equipped with a high / low speed switching device (19) for switching the peripheral speed of the front wheel (9) to a high speed state in which the peripheral speed of the front wheel (9) is made higher than that of the rear wheel (11) in conjunction with the rear wheel brake (37). ) Of a pair of left and right brake pedals (36) that can be uncoupled, and the high / low speed switching device (19) switches to a high speed state by detecting the connection of the pair of left and right brake pedals (36). A turning control device for a tractor, which is provided with a connection detector (38) for preventing replacement. 2. The tractor turning control device according to claim 1, further comprising a high speed detection for detecting a traveling speed to prevent the high / low speed switching device (19) from switching to a high speed state during high speed traveling. A turning control device for a tractor, which is provided with a device (29). 3. The rear wheel (11) is connected to left and right differential yoke shafts (49) of a rear wheel differential device (14), and the high-speed detector (29) includes left and right differential yoke shafts (49). Four
The tractor turning control device according to claim 2, wherein the rotation speed is detected in 9).