JPH03132483A - Four-wheel drive tractor - Google Patents

Abstract

PURPOSE:To prevent tear etc. of grass due to wheel peripheral speed becoming slower than actual wheel movement resulting from the peripheral speed difference between the front and rear wheels and the inner and outer wheels by interposing a center differential mechanism, which distributes power to front and rear wheels, on a transmission shaft installed in parallel with the output shaft of a main transmission device. CONSTITUTION:In a four-wheel driven tractor, the front and rear wheels are driven by further performing high/low aux. transmission in a transmission case M after the engine rotation is subjected to forward/reverse continuously variable transmission by a transmissive HST type transmission device H. The front end of an output shaft 2 of the transmission device H trotrudes in the transmis sion case M, and an aux. transmission shaft 3 is engagingly to the front end of this output shaft 2. A front differential case cylindrical shaft 8a is furnished in parallel with this output shaft 2 as transmission shaft facing against the aux. transmission shaft 3, and a center differential mechanism D is interposed in this cylindrical shaft 8a. This mechanism D transmits distributedly the power to a rear wheel drive shaft 4 and a front wheel drive shaft 5.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to a center differential mechanism for eliminating the difference in circumferential speed between front wheels and rear wheels in a four-wheel drive tractor.

(b) Prior Art Conventionally, a technique of interposing a center differential mechanism in a four-wheel drive tractor has been known.

(c) Problems to be Solved by the Invention In a four-wheel drive tractor, the rotational circumferential speed of the front wheels and the rotational circumferential speed of the rear wheels are configured such that the rotational circumferential speed of the front wheels is slightly faster than that of the front wheels.

However, if you accompany the aircraft for steering in this state, the center of turn is set on the extension line of the drive side axle, so the steering wheel will have a longer travel distance than the drive wheel, and the steering wheel will not be able to match the drive wheel. If the steering wheel is between the road and the circumferential speed, the circumferential speed of the steering wheel is slower than the moving speed, especially the circumferential speed of the steering wheel on the outside of the turn, which scrapes the field surface and creates unevenness. Problems were occurring, such as drying and muddying the lawn.

In the present invention, by configuring the main transmission with an H3T type transmission, a smooth start is obtained and the problem of raking the grass in the field is eliminated.

Furthermore, when attempting to arrange the center differential mechanism inside the transmission case of the tractor, it is difficult to arrange the center differential case because the center differential cases are arranged at the front and rear.

The present invention improves the arrangement and structure of the center teff mechanism, resulting in a compact arrangement and reliable support of the shaft at low cost.

(d) Means for Solving the Problems The problems to be solved by the present invention are as described above, and the means for solving them will now be explained.

A center teff mechanism that distributes and transmits running power to the front and rear wheels is installed on the transmission shaft, which is installed parallel to the output shaft of the main transmission.

Further, the main transmission is an H3T type transmission H.

Further, the differential case of the center teff mechanism is provided to extend in the axial direction, and one of the front wheel drive shaft and the rear wheel drive shaft that is given differential rotation is fitted onto the other shaft and supported by a bearing.

(E) Embodiment The problems to be solved by the present invention and the means for solving them are as described above.Next, the structure of the embodiment shown in the attached drawings will be explained.

In FIGS. 1, 2, and 3, the front wheels 1818 are large-diameter drive wheels, and the rear wheels 17, 17 are small-diameter steering shafts. Then, the rotation of the engine E in 1; 7h is transmitted to the LIST type transmission H via the universal joint 60, and the H3T type transmission H performs forward and backward continuously variable transmission. Furthermore, high and low sub-shifts are performed inside the mission case M, and the front wheels 18.18 and the rear wheels 17.1
It is driving 7. 6 is a rear wheel drive shaft.

A hydraulic cylinder 16 is arranged at the lower front of the mission case M, and the hydraulic cylinder 16 lifts the lift arm 1.
2 up and down, and the lift arm 12 connects to the lower link 1.
The mower device C is configured to be raised by contacting the mower device C from below.

A precleaner 75, a communication pipe 67, and an air cleaner 82 are arranged inside the bonnet 66, and the air cleaner 82 is arranged inside the cleaner chamber 90.

The engine 66 and the engine E are arranged on the fuselage frame 97, and the fuselage frame 97+.

A hydraulic oil cleaner 74 and a rashique 73 are also arranged. The vibro 3 extends from the hydraulic oil tank 91 arranged at the bottom of the seat 79 to the hydraulic oil cleaner 74, and the H
It extends from the ST type transmission H to the vibro 4 or the hydraulic oil cleaner 74. A fuel tank 69 is arranged inside the fender panel 80 on the right side of the seat 79.

B is a control device, which is composed of a handle 81 and a control column 83.

The lubricating oil in the transmission case M is sent to the hydraulic pump 94 by the suction vibro 2, and after being converted into pressure oil, it is sent to the hydraulic cylinder 16 via a pipe 70 and a valve.

65 is a rear axle, and 72 is a center pin support portion.

A hydraulic cylinder 16 is arranged at the lower front of the mission case M, and the hydraulic cylinder 16 rotates the hell crank arm 15, and the lift arm 12 attached to the hell crank arm 15 is rotated downward. The lift arm 12 contacts the lower link 11 from below, so that the mower device C can be moved upwardly.

Since the lift arm 12 is in contact with the lower link 11 from below and is configured to move vertically, the lift arm 12 is placed at a lower position than the lower link 11 in the normal reaping position, thereby creating a floating state. -ing

Further, when the lift arm 12 is raised to a certain angle by the hydraulic cylinder 16, the PTO clutch lever 23 is forcibly returned to its original position by the interlocking rod 19, and the PTO clutch lever 23 is interlocked to cut off the power of the PTO shaft 31.

Next, the configuration inside the mission case M will be explained with reference to FIGS. 4, 5, 6, 7, and 8.

The power from the engine E is transmitted via the universal joint 60 to the hydraulic pump shaft 1 of the H3T type transmission I that constitutes the main transmission, and the front end of the hydraulic pump shaft 1 is connected to the transmission case M. It protrudes inward and transmits power to the PTO clutch device.

Also, the rotation connected and disconnected by the PT○ clutch device is the PTO
Power is transmitted to the PTO shaft 31 via intermediate shafts 29 and 30. One-way clutch 4 between PT○ intermediate shafts 29 and 30
0 is inserted.

Let me explain about the PT○ clutch device.

A PT○ clutch device is disposed between the hydraulic pump shaft 1 and the PT○ intermediate shaft 29, and at the same time, an inertial idling brake body 26 that brakes inertial idling when the PT○ clutch is in a disengaged state.
or are installed in parallel.

The PTO clutch is operated by a PTO clutch 23, and an arm shaft 24 linked to the PTO clutch 23 or a shifter 25 protruding inside the mission case M and mounted on a slide shaft 24a as shown in FIG.
The inertial idling brake body 26 is configured to release the braking by pushing the inertial idling brake body 26 just before the wheel a reaches the crisscross joint. This configuration eliminates the possibility that the blade portion continues to rotate due to inertial idling when the mower device C is in an elevated position.

That is, the shifter 25a pushes the slider 25 slidably fitted onto the hydraulic pump shaft 1, as shown in FIG. 4, and the sliter 25 pushes the cam 28.

The clutch is connected by rotating the cam 28 and the clutch pressing portion 28a configured in a hell crank shape in the direction of pressing the friction plate, and the clutch pressing portion 28a presses the clutch friction plate.

Slightly before the clutch pressing portion 28a presses the friction plate, the end of the slider 25 or the end of the inertial idling brake body 26 is brought into contact, and the inertial idling brake body 26 is moved against the slide shaft 24a.
By "sliding" the top against the brake spring and pushing the inertial idling brake body 26 forward, the state of pressure braking by the brake spring is released and the inertial idling braking is released.

The front end of the hydraulic motor shaft 2, which is the output shaft of the H3T transmission H constituting the main transmission, protrudes into the transmission case M.
or is engaged and fitted.

A sub-transmission shaft 3 is disposed on the hydraulic motor shaft 2 which is the output shaft, and a front differential case cylindrical shaft 8a is provided as a transmission shaft parallel to the hydraulic motor shaft 2 and facing the sub-transmission shaft 3. The structure is such that a center differential mechanism is interposed on the differential case cylinder shaft 8a.

Power is distributed and transmitted to the rear wheel drive shaft 4 and the front wheel drive shaft 5 by a center differential mechanism provided on the front differential case cylindrical shaft 8a.

Double sliding gears 33 and 34 are slidably supported on the sub-shift shaft 3, and are moved back and forth by operating the sub-shift lever 42. The shifter 42a inside the mission case M is moved back and forth by the sub-shift lever 42, and is fitted into the slider grooves of the dual sliding gears 33 and 34. Moving gear 33
- 34 moves back and forth and meshes with either of the fixed gears 35 and 36 on the front differential case cylindrical shaft 8a.

Depending on the meshing state, the height of the sub-shift can be determined.

When the sliding gear 33 of the two sliding gears 33 and 34 meshes with the fixed gear 35 on the differential case cylindrical shaft 8, the height of the sub-shift is obtained. When engaged with the set gear 36, the sub-shift becomes low.

A center differential mechanism is arranged between the differential case 8, the front wheel drive shaft 5, and the rear wheel drive shaft 4, which provides differential rotation to the rear wheels 17, 17 and front wheels 18, 18.

That is, since the fixed gears 35 and 36 are fixedly installed on the front differential case cylindrical shaft 8a of the differential case 8, the rotation after the sub-shift is transmitted to the differential case 8.

The differential case 8 is composed of a front differential case cylinder shaft 8a to which fixed gears 35 and 36 are fixed, a pinion gear pivot tube 8b, and a rear differential case 8C. 0 It drives the differential case 8 on the outside of the differential mechanism.

A pinion 51 is revolved by a pinion shaft 50 fixed to the pinion gear pivot tube 8b, and power is distributed between the bevel gear 5a of the front wheel drive shaft 5 and the hel gear 4a of the rear wheel drive shaft 4 according to the running resistance. It's about communicating.

In the present invention, in order to make it possible to arrange the center differential mechanism in a narrow space under the sub-transmission shaft 3, fixed gears 35 and 3 are provided.
6 is a front TEF case cylinder shaft 8a extending from the differential case 8.
A bearing hole 4 is provided at the front end of the rear wheel drive shaft 4 in order to support the rear end of the front wheel drive shaft 5 which is fixedly mounted on the top and supported on a cantilever.
C, and the bearing portion 5 of the front wheel drive shaft 5 is inserted into the bearing hole 4C.
C is fitted, and the rear end of the front wheel drive shaft 5 is supported by a bearing.

In addition, fixed gears 35 and 36 are mounted on the front Tef case cylinder shaft 8a.
, the part where the differential lock slider 9 is arranged is improved, the differential lock slider 9 is interposed at the forward extending end of the differential case 8, and the differential lock is fixedly engaged with the front wheel drive shaft 5. It is possible to engage with the base locking body 53.

The differential slider 9 is spline-fitted to the front differential gear sleeve 8a, and the differential locking body 53 is also spline-fitted to the front wheel drive shaft 5, so that the differential locking body 53 and the differential slider 9 are engaged with each other. By doing so, the differential case 8, the rear wheel drive shaft 4, and the front wheel drive shaft 5 are integrated, resulting in a differential opening state.

A center differential lock lever 43 operates the center differential mechanism. The rotation of the center differential lock lever 43 is transmitted from the lever shaft 43a to the shifter 43b, and the shifter 43b is fitted into the groove of the differential lock slider 9.

By providing the center differential mechanism, the grass is prevented from becoming muddy and the soil surface is uneven, which are caused by the difference in circumferential speed between the front and rear wheels and the inner and outer wheels during running.

The front wheel drive shaft 5 drives the front wheels 18 through a normal front wheel differential mechanism, and the rear wheel drive shaft 4 drives the rear wheels 17 through a rear wheel differential mechanism.

(F) Effects of the Invention Since the present invention is constructed as described above, it has the following effects.

As claimed in claim (1), a center differential mechanism that distributes and transmits running power to the front wheels and rear wheels is interposed on the transmission shaft that is arranged parallel to the output shaft of the main transmission. It is possible to eliminate the cracks in the lawn caused by the circumferential speed of the wheels being slower than the actual movement of the wheels due to the difference in circumferential speed, and the unevenness of the soil surface caused by the wheels scratching the soil. It was possible.

Furthermore, it has become possible to arrange and store the center differential mechanism in a small space inside the transmission case M.

It also became possible to arrange the sub-transmission device in a simple configuration.

As claimed in claim (2), by using the HST type transmission H as the main transmission, the starting and acceleration of the four-wheel drive tractor can be smoothed by the H3T type transmission H,
Furthermore, it was possible to eliminate the mushy condition of the lawn.

According to claim (3), the differential case of the center differential mechanism is extended in the axial direction, and one of the front wheel drive shaft and the rear wheel drive shaft, which is given differential rotation, is fitted onto the other shaft to support the bearing. Therefore, the auxiliary transmission mechanism and the differential opening/lock mechanism can be constructed compactly, and the shaft support of the rear wheel drive shaft 4 and the front wheel drive shaft 5 can be provided at an inexpensive and reliable structure.

[Brief explanation of the drawing]

Fig. 1 is a plan view of a running vehicle equipped with the front mower device C of the present invention, Fig. 2 is a side view, Fig. 3 is an enlarged perspective view of the side, and Fig. 4 is an H3T type transmission H and a transmission case. M
5 is a plan view of the PTo clutch operating section, FIG. 6 is a plan view of the center differential lock lever shaft 43a and center differential lock shifter 43b, FIG. 7 is a rear sectional view of the transmission case M, and FIG. 8 is a plan view of the PTo clutch operating section. is an enlarged side cross-sectional view of a sub-transmission device and a center differential mechanism. 3 4 M ・ ・ H ・ ・ C ・ ・ D ・ ・ 1 ・ 2 ・ 3 ・ 4 ・ 5 ・ ・ 8 ・ 8 a ・ 9 ・ ・ 3 35°・Mission case・H3T type transmission・Mower Equipment・Center differential mechanism・Hydraulic pump shaft・Hydraulic motor shaft・Sub-transmission shaft・Rear wheel drive shaft・Front wheel drive shaft・・Differential case・・Front differential case cylindrical shaft・・Teflo sock slider 34・・Double sliding gear 36...Fixed gear

Claims (3)

[Claims] (1) A four-wheel drive tractor characterized by having a center differential mechanism installed on a transmission shaft arranged in parallel with the output shaft of a main transmission, which distributes and transmits running power to front wheels and rear wheels. (2) The four-wheel drive tractor according to claim (1), wherein the main transmission is an HST type transmission H. (3) In claim (1), the differential case of the center differential mechanism is extended in the axial direction, and one of the front wheel drive shaft or the rear wheel drive shaft that is given differential rotation is fitted onto the other shaft. A four-wheel drive tractor characterized by bearing support.