JPH06219180A - Two wheel drive-four wheel drive switching device for tractor - Google Patents

Abstract

PURPOSE:To reduce wear between the shifter-boss of a two wheel drive-four wheel drive switching device and the shifter pin for operating the boss in a travel transmission clutch of a tractor. CONSTITUTION:The two wheel drive-four wheel drive switching device is provided with an operating lever 3 for switching travel transmission to a free position A at which the travel transmission can be automatically switched to two wheel drive and four wheel drive by operating a transmission clutch 2 by means of the operation of a shifter 1, and to a lock-position B at which the travel transmission is locked to four wheel drive. A hook arm 6 which can be freely turned through a spring 4 and on which a hook 5 capable of locking the free position A of the operating lever 3 is formed, is provided between the operating lever 3 and the shifter. By operating the operating lever to the free position A, the hook arm is turned against the spring 4 to be automatically locked to the hook 5. A stopper 7 for locking the operating lever 3 which is turned to the lock-position B by the spring 4 by unlocking the operating lever 3 by means of the operation of the hook arm 6, is provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a two-wheel-drive / four-wheel drive switching device for switching the traveling transmission of a tractor between two-wheel drive and four-wheel drive.

[0002]

2. Description of the Related Art In a two-wheel-drive / four-wheel drive switching device for a tractor having a configuration in which a transmission clutch can be turned on and off by a shifter operation, the shifter operation is tensioned by a spring. If the transmission clutch is maintained under pressure, the rotating shifter boss and the shifter pin that operates the rotating boss are always in a rotational friction state and are easily worn.

According to the present invention, the shifter position which is operated by the shifter is locked by the stopper at the position where the transmission clutch is engaged by the spring tension so that the shifter position is regulated to prevent the above-mentioned defects. Resolve.

[0004]

The present invention is a shifter-1.
With the operation lever-3 for operating the transmission clutch 2 to automatically switch the traveling transmission between the 2WD and the 4WD and the lock position B fixed to the 4WD, A hook arm 6 is provided between the operation lever 3 and the operation lever 3 so that the hook 5 is rotatable via a spring 4 and can lock the free position A of the operation lever-3. By operating 3 to the free position A, the hook arm 6 can be automatically locked while rotating the hook arm 6 against the spring 4, and by operating the hook arm 6, the operation lever 3 can be operated. A two-wheel-drive, four-wheel drive switching device for a tractor is provided, which is provided with a stopper-7 that locks the operation lever-3 that is rotated to the lock position B by the outer spring 4 by releasing the lock.

[0005]

OPERATION AND EFFECT OF THE INVENTION The operation lever-3 is at the free position A.
Since the shifter-1 does not press the transmission clutch 2 when the state is 1), the transmission clutch 2 is in the transmission disengaged state or in the automatic transmission engaged state. It is two-wheel drive when the transmission is turned off, and is automatically transmitted as four-wheel drive when the transmission is turned on by a sensor or the like. When the operation lever 3 is in the lock position B, the shifter 1 presses the transmission clutch 2 to forcibly engage and disengage the transmission clutch 2 regardless of whether it is automatically engaged or disengaged.

Such a free position A operation is performed by the operation lever.
3 and the hook position 6 is used to operate the lock position B.
Of these, since the operation to the free position A is performed against the tension of the spring 4, the hook arm 6 is rotated by the spring 4, and the hook 5 is attached to the operation lever 3 at the free position A. Is locked and fixed at the free position A. At this time, since the shifter-1 does not press the transmission clutch 2, there is almost no rotational friction between the shifter boss integrated with the shifter-1 and the shifter pin. Further, in the operation to the lock position B, the hook 5 is disengaged from the operation lever-3 by operating the hook arm 6 against the spring 4, and the operation lever-3 is also locked to the lock position B by the spring 4. The operation is maintained. At this time, the stopper 7 holds the lock position B by the spring 4. Therefore, even if the operating lever 3 is tensioned to the lock position B side by the spring 4, the limit position is locked by the stopper 7, so that the shifter boss by the shifter pin and the integral shifter 1 are connected to the transmission clutch 2. Does not push to the side.

Further, when the transmission clutch 2 is in the form of a dog clutch, for example, the operation lever 3 is operated in the direction in which the transmission clutch 2 enters through the tensioning action of the spring 4. Even if the peaks and valleys of the clutch do not immediately engage, the operation lever-3 should be hooked 5
When the dog clutch is engaged with the dog clutch, the dog clutch is automatically engaged with the dog clutch.

As described above, the shifter-1 of the 2WD-4WD switching device
Is smoothly switched by the operation lever-3, the hook arm 6, the spring 4, the stopper 7, etc., and when the transmission clutch 2 is engaged at the lock position B, the shifter-1 is constantly strongly pressed. Since this is not done, the frictional resistance and wear of the shifter boss and the shifter pin that operate this shifter-1 can be reduced.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A clutch housing 8, a space case 9, a transmission case 10 and the like which compose a tractor vehicle body are connected in series from the engine E side at the rear end toward the front end to form an integral structure. By engaging the main clutch 11 in the housing 8, the traveling interlocking shaft 12 and the power take-out interlocking shaft 13 are transmitted. The traveling interlocking shaft is interlocked with a differential device 14 in a mission case 10 through a hydraulic continuously variable transmission device HST in a space case 9. From the differential device 14 to the left and right sides of the mission case 10. The front wheel 20 in the axle housing 23 protruding toward the front can be driven and driven. Further, a transmission device 15 of the transmission case 10 is interlocked with a diff device 18 in an axle housing 19 through an input shaft 16 which is a rear wheel interlocking shaft, an output shaft 17, a transmission clutch 2, etc. The rear wheels of the left and right ends of 19 are driven. After that, the steering wheel 22 operates the wheels 21 to interlock.

The power take-off interlocking shaft 13 can drive the power take-out shaft PTO on the front side of the mission case 10 via the interlocking shaft 24, the transmission 25 and the like. The power take-off shaft PTO is interlocked so that a working machine mounted on the front part of the vehicle body, for example, the mower 26, can be cut and transmitted. Reference numeral 27 is a cockpit, 28 is a speed change pedal, and the axial pressure continuously variable transmission HS
The T can be operated to shift from the neutral position to the forward F high speed position or the reverse R high speed position.

The transmission clutch 2 is in the form of a dog clutch and is formed in the clutch case 29 extending between the input shaft 16 and the output shaft 17. A spline-fitting cam 32 and a movable dog clutch 30 are movably provided at a tip end portion of the input shaft 16 by a clutch spring 31, a cam 32, and the like, and a boss portion 33 of the cam 32 slides in an axial direction. The movable lock pin 34 has a structure capable of rotating integrally, and the tip of the lock pin 34 is at the movable dog clutch 3
The rear end of the shifter boss 35 is brought close to the rear of the shifter boss 35 and the base end is engaged with the shifter boss 35.
The movable dog clutch 30 is spline-fitted to the end side of the output shaft 17 through the lock pin 34 by a shift operation in the axial direction by a shifter pin 37 engaged with the fixed dog clutch 38 that integrally rotates. To the side, spring 3
It is configured such that the transmission clutch 2 can be engaged by moving it against 1 and engaging it.

A brake 39 is rotatably fitted to the output shaft 17 side and rotatably fitted with a brake metal 41 to the outer circumference of a casing 40 which covers the outer circumference of the transmission clutch 2. There is. Part of the protrusion 42 of the brake metal 41 is
It is engaged with the clutch case 29 to prevent it from rotating. The brake 39 is tightened by a spring 43 on the outer periphery of the brake metal 41 to perform frictional braking. These
The key 39, the brake metal 41, and the casing 40 are relatively rotatable.

A brake arm 44 is projected toward the brake 39 at two locations on the outer periphery of the movable dog clutch 30, and the brake arm 44 is axially resisted against the brake 39. It is engaged so that it can slide back and forth. If the rotation of the output shaft 17 side with respect to the input shaft 16 is fast or slow with respect to the input shaft 16 without the forced locking by the shifter-1 and the lock pin 34,
A frictional resistance due to the brake 39 is exerted on the movable dog clutch 30, so that the movable dog clutch 30, which is separated by the tension force of the spring 31, is pushed by the cam 32 that rotates integrally with the input shaft 16 and is moved by the spring 31. Moved against
The fixed dog clutch 38 is engaged and transmitted. (FIG. 5 → FIG. 6) Therefore, when the rotation of the output shaft 17 becomes slow due to the load, the transmission clutch 2 is automatically engaged and the drive from the input shaft 16 is performed.

The operation lever 3 has a base portion provided with a shifter pin 37 which is eccentric to the operation rotation shaft 45, and the shifter pin 37 is engaged with the shifter groove 36 of the shifter boss 35. The shifter boss 35 can be manually operated to the free position A, and the tip portion of the hook arm 6 can be manually operated to the lock position B. Reference numeral 39 is a left steering brake pedal, 40 is a right steering brake pedal, 41 is a master brake pedal, and 42 is a clutch pedal. Reference numeral 43 denotes an operation panel on the side of the cockpit 27, which includes a PTO gearshift lever 44, an auxiliary gearshift lever 45, a lift hydraulic lever that moves the lift arm up and down, and a gearshift pedal 28 of the hydraulic continuously variable transmission HST. Otcle for maintaining the gear shift position
It has a slipper 47 and the like.

The PTO shift lever 4 of this operation panel 43
A check plate 48 is attached to the position 4. In the front mower, the PTO gear shift lever 44 is normally operated at the high speed position H, and the low speed position L is used only for other working machines in many cases.
If the work is carried out at, the mowing performance of the mower 26 will be significantly reduced. In order to prevent this, the check plate 48 is configured to be switched by a simple operation of the knob bolt 49 according to the work so as to check the shift position of the high speed position H or the low speed position L.

A check plate 48 having restricting portions 51 and 52 formed in front and back along a lever groove 50 of a PTO shift lever 44 of the operation panel 43 is provided below the operation panel 43 with a tightening bolt 54. The knob bolt 49, the long holes 53 at regular intervals in the front-rear direction, and the like can be reversed in the front-back direction or can be switched between movements. When the low speed position L of the PTO gear shift lever 44 is restricted, the knob bolt 49 is loosened to move the check plate 48 to the high speed position H side and fixed by tightening. The operation is restricted between the neutral position N and the high speed position H by being restricted to. On the contrary, when restricting the high speed position H, if the check plate 48 is reversed or moved to the low speed position L side, the PTO shift lever-4
4 is regulated by the regulation portion 52, and the neutral position N and the low speed position L
You can only operate between and.

[Brief description of drawings]

FIG. 1 is a side view of an operation lever portion.

FIG. 2 is a side view showing the operation.

FIG. 3 is a plan view thereof.

FIG. 4 is an enlarged side view of a transmission clutch unit.

FIG. 5 is a side view showing a part of the operation thereof.

FIG. 6 is a side view showing the operation of a part thereof.

FIG. 7 is a side view of the transmission unit of the tractor.

FIG. 8 is a side view of the tractor.

FIG. 9 is a plan view thereof.

FIG. 10 is an enlarged plan view of the operation panel unit.

FIG. 11 is a front view thereof.

[Explanation of symbols]

 1 Shifter 2 Transmission clutch 3 Operation lever 4 Spring 5 Hook 6 Hook arm 7 Stopper A Free position B Lock position

Claims (1)

[Claims] 1. An operation for operating a transmission clutch 2 by operating a shifter-1 to switch between a free position A in which traveling transmission can be automatically switched between two-wheel drive and four-wheel drive, and a lock position B fixed in four-wheel drive. With the lever-3, this operation lever-3
And the operation lever is rotatable via a spring 4 between
3 has a hook arm 6 formed with a hook 5 capable of locking the free position A, and by operating this operating lever 3 to the free position A, the hook arm 6 is resisted against the spring 4. Can be automatically locked to the hook 5 while rotating, and the operation lever 3 is unlocked by operating the hook arm 6 to rotate the lever 3 to the lock position B. 2WD / 4WD switching device for a tractor, which is provided with a stopper-7 that locks 3 in place.