JP2504658Y2 - Safety device in front wheel speed increasing device of tractor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to a safety device for a tractor equipped with a front wheel speed increasing device.

(B) Conventional technology Conventionally, a front wheel steering angle sensor that detects that the front wheel steering angle has exceeded a predetermined value is attached to the front wheel steering system, and when the front wheel steering angle sensor is in the detection state, the front wheel speed increasing mechanism operates. We have already proposed a tractor that switches to speed-up so that it will not be speeded up when it is in a non-detection state, in which the front wheels are not speeded up at high speeds in the traveling system transmission.

(C) Problems to be solved by the invention In the safety device of the known front tractor speed increasing device of the tractor, when the traveling speed is changed to a high speed while traveling on the road, the front wheel cutting angle sensor has a predetermined cutting angle or more. Even if the front wheels are not accelerated, the speed should be set to a high speed when maneuvering that does not require high-speed turning, such as when entering or exiting the field or entering or exiting a narrow storage area. Without
In such a case, if the front wheel turning angle is set to a predetermined value or more, it is extremely dangerous because the aircraft suddenly turns rapidly when the driver does not expect, and there is a problem such as damage to the tractor or obstacles. It was

(D) Means for Solving Problems The present invention has a front-wheel speed-up mechanism that switches to speed-up when the front-wheel turning-angle sensor detects that the turning angle exceeds a predetermined turning angle, in the transmission system of the front wheels. PT that can be shifted to the mission case
In a tractor equipped with an O-axis, the PTO gearbox is equipped with a PTO gearshift switch that is in the detection state when it is in the transmission state and in the non-detection state when it is in the neutral state, and controls the front wheel speed-up mechanism. In the circuit, in the state where the front wheel turning angle sensor has detected that the turning angle is equal to or more than a predetermined turning angle, and the PTO speed change switch of the PTO transmission is in the detection state,
The problem was solved by making the front wheel speed-up mechanism switch to speed-up so that the aircraft does not turn rapidly when the PTO shaft is not driven.

(E) Action A work machine that puts the tractor into the field and is attached to the rear,
For example, when driving the cultivator with the PTO shaft running and turning the aircraft on the headland in the field, the front wheel speed increasing mechanism operates when the front wheel cutting angle sensor detects that the front wheel cutting angle has exceeded the predetermined value. Then, the front wheels are accelerated, and the aircraft rapidly turns.

Also, when the tractor travels on the road, when it is put in and out of the field, or when it is put in and out of a narrow storage place, the PTO gearbox is neutral and is not transmitted, and as a result, the detection switch attached to it. Since it is turned off, even if the front wheel breaking angle exceeds a predetermined value and the front wheel breaking angle sensor is detected, the front wheel speed increasing device does not switch to speed increasing and safe driving can be performed.

(F) Embodiment An embodiment of the present invention will be described with reference to the drawings. The tractor 1 has front wheels 2 and 2 and rear wheels 3 and 3, and the rear wheels 3 and 3 are engines 4.
Is driven by a traveling transmission including a clutch housing and a large number of transmission gears in the transmission case 5 and a rear wheel differential mechanism, and the front wheels 2 and 2 are driven by the traveling transmission.
The front wheel 2 is driven by the front wheel speed increasing mechanism 6 and the front wheel differential mechanism 9 installed in the center of the front axle case 7, and the like.
The steering operation system is provided with a front wheel turning angle sensor 8 which becomes a detection state (ON) when the turning angle of the front wheels exceeds a predetermined value.

In the front wheel speed increasing mechanism 6, the front differential shaft 10 is an input shaft of the front axle case 7 (pinion shaft of the front wheel differential mechanism).
A differential mechanism 11 connected to the rear differential shaft 12, a disc brake 13 mounted on a rear differential shaft 12, a cylinder shaft 14 extending rearward from the differential case, and a differential lock mechanism 15 interposed on the rear differential shaft 12. And the disc brake 13
Is driven by hydraulic oil that is pressure-fed from a pump P via a hydraulic circuit 17 connected via an electromagnetic valve 16.

Also, the PT projecting rearward from the mission case 5
The O shaft 18 is driven via a PTO transmission installed inside the rear part of the mission case 5, and the PTO transmission is
The PTO gear shift lever 21 arranged on the side of the driver's seat 20 can switch between first speed, second gear, and neutral, and non-transmission is set at the neutral position of the PTO gear shift lever 21 or the PTO clutch disengaged position. There is a PTO gearshift switch 22 that turns off only at, and it turns on only when the gearshift lever that operates the independent PTO shaft is set to the neutral position or the clutch disengaged position. Is attached.

Then, as shown in FIG. 3, the control circuit of the electromagnetic valve 16 is turned off when the traveling speed change lever is set to the high speed position.
When the high-speed switch 25 and the front wheel speed increase switching lever 26 are set to the upper two-wheel drive position, the sleeve 27 is moved rearward to release the diff lock, and when the intermediate four-wheel drive position is set, the sleeve 27 is set to the position shown in FIG. In the type that moves to the lock position shown in Fig. 3 and is differentially locked, and is set to the front wheel speed-up standby position below, the rear part of the sleeve 27 pushes the ball 28 into the diff-locked state and is placed in front of the front wheel speed-up standby position. 30, the PTO speed change switch 22, the IND switch 23, and the front wheel breaking angle sensor 8 are inserted in series, and a manual switch 31 that is provided with an operation panel and is turned on when performing plow work or other towing work is used. Since it is inserted in parallel with the speed change switch 22 and the IND switch 23, the result of detection by the front wheel breaking angle sensor 8 is also detected when the towing work is performed with the switches 22 and 23 turned off. The front wheels 2 can be accelerated to rapidly turn the machine body.

In the above tractor, when connecting a rotary tiller etc. to the rear part and performing work while driving it with the PTO shaft 18, since the speed change lever is set to the low speed position, the high speed switch 25 is ON, the front wheel speed increase switching. The lever 26 is set to the front wheel acceleration standby position.
The ON, PTO speed change switch 22 and IND switch 23 are also turned on. When the aircraft reaches the paddy field in this state, if the steering wheel 33 is turned and the front wheel turning angle becomes a predetermined value or more, the turning is turned off. The angle sensor 8 is turned on, whereby the solenoid of the electromagnetic valve 16 is energized and switched, and the pump P
The hydraulic oil from the hydraulic circuit 17 pushes the spool 32, which also functions as a shift rail to which the shift fork is fixed, forward to release the differential lock, and then operates the disc brake 13, so that the rear operating shaft 12 stops. , The front differential shaft 10 is driven at double speed, which causes the front wheels to rotate at high speed,
The aircraft will make a rapid turn.

Also, when the tractor is put in or taken out of the field, or when the tractor is put in or taken out of a small storage space, the traveling speed change lever is set to the low speed position, so the high speed switch is turned on.
N, the front speed change switch 30 is ON when the front wheel speed increase switching lever 26 is still set to the front wheel speed increase standby position, but the work machine is not driven, so the PTO speed change switch 2
2 and IND switch 23 are OFF.

Therefore, during driving, the steering wheel 33 is largely rotated to bring the front wheel turning angle to a predetermined value or more, and the solenoid of the electromagnetic valve 16 is not energized even if the front wheel turning angle sensor 8 is in the detection state. Since the front wheel speed-increasing mechanism 6 does not switch to high speed, the machine does not suddenly turn, and safe driving operation can be performed.

(G) Effect of the Invention According to the invention, as described above, the transmission system of the front wheels 2 is provided with the front wheel speed-increasing mechanism 6 which is switched to the speed-increasing mode when the front-wheel cutting-angle sensor 8 detects that the angle is equal to or more than a predetermined cutting angle. Then, in the tractor in which the transmission case 5 is equipped with the shiftable PTO shaft 18, the PTO transmission is in the detection state when it is in the transmission state and in the non-detection state when it is in the neutral state. Is attached, the control circuit of the front wheel speed increasing mechanism 6 detects that the front wheel turning angle sensor 8 is at a predetermined turning angle or more, and the PTO of the PTO transmission.
When the speed change switch 22 is in the detection state, the front wheel speed increasing mechanism 6 is configured to switch to speed increasing. Therefore, when the work machine is driven by the PTO shaft 18 and the tractor is run to perform work, the vehicle swings. When the front wheel turning angle sensor 8 detects that the turning angle of the front wheels has exceeded a predetermined value by turning the steering handle 33 to a large extent, the front wheel speed-increasing transmission mechanism 6 is switched to a high speed to quickly move the aircraft. However, when the tractor is moved in and out of the field or in a narrow storage space, the PTO shaft is not driven and the detection switch attached to it (for example, PTO Since the speed change switch) is turned off, even if the front wheel cutting angle sensor 8 is detected by turning the steering wheel largely, the front wheel speed increasing speed changing mechanism 6
Does not switch at high speed, and safe driving can be performed while preventing the tractor from colliding with an obstacle or causing personal injury.

[Brief description of drawings]

FIG. 1 is a side view of a tractor, FIG. 2 is a hydraulic circuit diagram of a front wheel speed increasing mechanism, and FIG. 3 is a control circuit diagram of an electromagnetic valve. 2 ... front wheel, 5 ... mission case, 6 ... front wheel speed-up mechanism, 8 ... front wheel breaking angle sensor, 10, 12 ... differential shaft, 1
5 …… Differential lock mechanism, 16 …… Electromagnetic valve, 18 …… PTO
Axis, 22 …… PTO speed change switch, 25 …… High speed switch

Claims (1)

(57) [Scope of utility model registration request] 1. A front wheel breaking angle sensor 8 for a transmission system of the front wheel 2.
In the tractor in which the transmission case 5 is equipped with the PTO shaft 18 capable of shifting, the front wheel speed increasing mechanism 6 that switches to speed increasing when it is detected that
The PTO transmission of the shaft 18 is provided with a PTO transmission switch 22 which is in a detection state when it is in a transmission state and is in a non-detection state when it is in a neutral state. When the turning angle sensor 8 has detected that the turning angle is equal to or greater than a predetermined turning angle, and the PTO of the PTO transmission is
A safety device in a front wheel speed increasing device for a tractor, characterized in that the front wheel speed increasing mechanism 6 is configured to switch to an increased speed when the speed change switch 22 is in a detection state.