JP3221125B2 - Tractor 2WD 4WD switching device - Google Patents

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 power 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 in which a transmission clutch can be turned on and off by a shifter operation, this shifter operation is performed by a spring tension. If the transmission clutch is maintained under pressure, the rotating shifter boss and the shifter pin operating the shifter boss are always in a state of rotational friction, and are liable to wear.

According to the present invention, the shifter lever operated by the shifter is locked by a stopper at a position where the transmission clutch is engaged by a spring tension so as to restrict the shifter position, thereby solving the above-mentioned defects. To eliminate.

[0004]

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

[0005]

Operation and Effect of the Invention The operation lever-3 is in the free position A.
, The shifter-1 does not press the transmission clutch 2, so that the transmission clutch 2 is in the transmission off state or in the automatic transmission on state. When the transmission is off, it is a two-wheel drive, and when the transmission is on, it is automatically transmitted as a four-wheel drive by sensor detection or the like. When the operation lever 3 is at the lock position B, the shifter 1 presses the transmission clutch 2 to forcibly engage and transmit as a four-wheel drive regardless of the automatic on / off operation.

[0006] Such a free position A operation is performed by an operation lever.
3 and the lock position B operation is performed by the hook arm 6.
Of these operations, the operation to the free position A is performed against the tension of the spring 4, so that the hook 4 is rotated by the spring 4 and the hook 5 is moved 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 and the shifter pin integrated with the shifter-1. 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 moved to the lock position B by the spring 4. The operation is maintained. At this time, the lock position B by the spring 4 is held by the stopper 7. Therefore, even if the operating lever 3 is tensioned toward the lock position B 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 There is no pressing to the side.

When the transmission clutch 2 is in the form of a dog clutch, for example, the operation lever 3 is operated in the direction of entering the transmission clutch 2 through the tensioning action of the spring 4 when the operation lever 3 is operated. Even if the peak and the valley of the clutch do not immediately engage, the operation lever-3 is hooked up to the hook 5.
The dog clutch is automatically engaged by being released from the lock position to be freely rotatable to the lock position B.

Thus, the shifter-1 of the two-wheel drive four-wheel drive switching device
Is smoothly switched by the operating lever-3, the hook arm 6, the spring 4, the stopper 7, and the like, and at the time of the operation of engaging the transmission clutch 2 at the lock position B, the shifter-1 is always strongly pressed. Therefore, the frictional resistance and wear of the shifter boss, shifter pin, and the like that operate the shifter-1 can be reduced.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A clutch housing 8, a space case 9, a transmission case 10 and the like constituting a tractor body are connected in series from a rear end engine E side to a front end to form an integral structure. When the main clutch 11 in the housing 8 is engaged, 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 the transmission case 10 via a hydraulic continuously variable transmission HST in the space case 9, and from the differential device 14 to the left and right sides of the transmission case 10. The front wheels 20 in the axle housing 23 projecting toward the front can be driven and run. Also, a differential device 18 in an axle housing 19 is interlocked with a transmission 15 of the transmission case 10 via an input shaft 16, an output shaft 17 and a transmission clutch 2 which are rear wheel interlocking shafts. Drive the rear wheels at the right and left ends of the 19. Thereafter, the wheels 21 are steered by the steering handle 22.

The power take-out interlocking shaft 13 is configured to drive the power take-out shaft PTO on the front side of the transmission case 10 via an interlocking shaft 24, a transmission 25 and the like. The power take-off shaft PTO is operatively connected to a working machine mounted on the front part of the vehicle body, for example, a mower 26 so as to transmit the mowing. 27 is a cockpit, 28 is a speed change pedal, and the shaft pressure continuously variable transmission HS
T can be shifted from a neutral position to a forward F high-speed position or a reverse R high-speed position.

The configuration of the transmission clutch 2 is a dog clutch configuration and is provided in the clutch case 29 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 the distal end of the input shaft 16 by a clutch spring 31, a cam 32, and the like. The movable lock pin 34 can rotate integrally with the movable dog clutch 3.
0 and the base end is engaged with the shifter boss 35, and the shifter boss 35 is inserted into the shifter groove 36.
The movable dog clutch 30 is spline-fitted to the end side of the output shaft 17 through the lock pin 34 by the shift operation in the axial direction by the shifter pin 37 engaged with the fixed dog clutch 38 which rotates integrally with the movable dog clutch 30. Spring 3 to the side
The transmission clutch 2 can be engaged by being moved against and engaged with the transmission clutch 2.

A brake 39 is rotatably fitted on the output shaft 17 side and rotatably fitted with a brake metal 41 on the outer periphery of a casing 40 which covers the outer periphery of the transmission clutch 2. I have. A part of the projection 42 of the brake metal 41 is
The clutch case 29 is engaged to prevent rotation. The brake 39 is fastened to the outer periphery of the brake metal 41 by a spring 43 to perform friction braking. These bra
The key 39, the brake metal 41, and the casing 40 are relatively rotatable.

A brake arm 44 is protruded toward the brake 39 at two locations on the outer periphery of the movable dog clutch 30, and the brake arm 44 extends in the axial direction against the brake 39. To slide freely forward and backward. Without the forced lock by the shifter-1 and the lock pin 34, when in the free position A, when there is a rotation difference between the input shaft 16 and the output shaft 17 side, which is faster or slower,
Friction resistance by the brake 39 acts on the movable dog clutch 30, whereby the movable dog clutch 30, which is separated by the tension of the spring 31, is pushed by the cam 32 that rotates integrally with the input shaft 16 and is pressed by the spring 31. Moved against
It is engaged with the fixed dog clutch 38 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.

At the base of the operation lever-3, there is provided a shifter pin 37 eccentric to the operation rotation shaft 45, and this 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 of the hook arm 6 can be manually operated to the lock position B. 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 shift lever 44, an auxiliary shift lever 45, a lift hydraulic lever for moving the lift arm up and down, and a non-operating switch by the shift pedal 28 of the hydraulic continuously variable transmission HST. Vehicle for maintaining the gear position
It has a displacement lever 47 and the like.

The PTO shift lever-4 on the operation panel 43
4 is provided with a check plate 48. In the front mower, the PTO shift lever 44 is normally set at the high speed position H, and the low speed position L is often used only for other work equipment.
, The mowing performance of the mower 26 is significantly reduced. In order to prevent this, the check plate 48 can 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 restraining plate 48 having regulating portions 51 and 52 formed back and forth along a lever groove 50 of a PTO shift lever 44 of the operation panel 43 is provided with a tightening bolt 54 below the operation panel 43. , A knob bolt 49, a long hole 53 at regular intervals in the front-rear direction, or the like, so that the front-rear inversion or the movement can be switched. When the low-speed position L of the PTO shift lever 44 is regulated, the knob bolt 49 is loosened and the restraint plate 48 is moved to the high-speed position H side to tighten and fix the PTO shift lever 44. Only the operation between the neutral position N and the high-speed position H can be performed. In order to regulate the high-speed position H, on the contrary, if the retraction plate 48 is reversed or moved back and forth toward the low-speed position L, the PTO shift lever-4 can be controlled.
4 is regulated by the regulating portion 52, and the neutral position N and the low speed position L
You can only operate between them.

[Brief description of the drawings]

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

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.

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

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]

 DESCRIPTION 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

Continuation of the front page (56) References JP-A-2-117430 (JP, A) JP-A-53-100537 (JP, A) JP-A-52-2230 (JP, A) Jpn. , U) Japanese Utility Model Showa 55-167827 (JP, U) Japanese Utility Model Application Hei 2-71032 (JP, U) Japanese Utility Model Showa 63-16931 (JP, U) (58) Fields surveyed (Int. Cl. ⁷ , DB Name) B60K 23/00-23/08

Claims (1)

(57) [Claims] 1. A free position (A) in which the transmission can be automatically switched between a two-wheel drive and a four-wheel drive by operating a transmission clutch (2) by operation of a shifter (1), and a lock fixed to the four-wheel drive. An operating lever (3) for switching to the position (B), and rotatable between the operating lever (3) via a spring (4) and free of the operating lever (3). A hook arm having a hook (5) capable of locking the position (A)
By operating the operating lever (3) to the free position (A), the hook (6) is rotated while the hook arm (6) is rotated against the spring (4). 5) can be automatically locked, and by operating the hook arm (6), the operation lever (3) is unlocked, and the spring (4) rotates the lock lever to the lock position (B). A tractor two-wheel drive four-wheel drive switching device provided with a stopper (7) for locking the lever (3).