JPS6233629Y2 - - Google Patents

Description

[Detailed description of the invention] The invention provides a transmission case having an opening on the underside thereof, a case covering the opening and protruding downward from the transmission case, and a front wheel transmission shaft supported within the transmission case.
The present invention relates to a front wheel drive structure for an agricultural tractor, in which a front wheel drive shaft supported within the case is interlocked with the front wheel drive shaft via a gear-type transmission mechanism that is installed so as to pass through the opening.

In recent years, as the types of attachment work devices attached to the above agricultural tractors have increased, it has become possible to replace front wheels with different diameters to improve maneuverability or increase ground clearance. things are desired. Therefore, in order to meet the above requirements, it is necessary to change and adjust the transmission ratio in the gear type transmission mechanism so as not to cause a change in circumferential speed between the front wheel and the rear wheel, regardless of a change in the diameter of the front wheel. However, in the conventional front wheel drive structure, as shown in FIG. 5, a front wheel transmission shaft 14 is interlocked and connected to a pinion shaft 13 input to the rear wheel differential mechanism 9 so as to rotate integrally through gear transmission. The mission case 17 is axially mounted across the partition walls 20 and 20a adjacent to each other in the front and back direction, and the portion that is axially supported between the partition walls 20 and 20a is made to face the opening 18 formed in the mission case 17. At the same time, the case 21 is fixed in a position covering this opening 18, and the rear end side of the front wheel drive shaft 16 supported in the case 21 and the front wheel transmission shaft 14 are connected to both bulkheads 20 of the front wheel transmission shaft 14. , 20a, the transmission gear 23 is fitted onto the shaft extending between
and the driven gear 25 fitted on the rear end side of the front wheel drive shaft 16 are interlocked and connected via a gear type transmission mechanism 19 configured to interlock with each other through the opening 18, so that the gear type transmission mechanism 19 To change and adjust the transmission ratio of transmission case 17,
and the entire case 21, and separate the front wheel transmission shaft 14.
It is necessary to remove the front wheel from the partition wall 20a and replace the transmission gear 23, and also to remove the front wheel drive shaft 16 from the case 21 and replace the driven gear 25, which poses a problem in that disassembly and reassembly work is time-consuming.

In view of the above points, the present invention aims to make it possible to easily change the transmission ratio in a gear type transmission mechanism by devising the support structure of the front wheel transmission shaft and the front wheel drive shaft. purpose.

Next, embodiments of the present invention will be described in detail based on the drawings.

A driver's seat 3 is mounted on a vehicle body with wheels 1 and 2 mounted on the front and rear wheels.
At the same time, a lift arm 5 is provided at the rear to suspend the power take-off shaft 4 and the attachment working device so as to be able to move up and down. A rear wheel differential mechanism 9 and a front wheel differential mechanism 10 are connected to the rear wheel differential mechanism 9 and the front wheel differential mechanism 10 via the speed change mechanism 7, first and second width change mechanisms 8a and 8b.
and to the rear wheels 2, 2 and the front wheels 1, 1 through both differential mechanisms 9, 10, respectively, and the front wheels 1, 1 are used as steering wheels. This configuration constitutes a four-wheel drive type agricultural tractor.

To drive the front wheels 1, 1, a gear is transmitted from a pinion shaft 13 for the rear wheel differential mechanism 9 to the first transmission shaft 12 in which the gear type transmission member 11 of the second width change mechanism 8b is loosely fitted. , the first transmission shaft 1
A second transmission shaft 14 as a front wheel transmission shaft is connected to the front wheel differential mechanism 10 via a clutch 15 so that it can be operated on and off freely and concentrically. Front wheel drive shaft 16 for
The transmission is transmitted through an opening 18 formed in the transmission case 17 and via a gear type transmission mechanism 19, and by operating the clutch 15, a two-wheel drive state using only the rear wheels 2, 2 and a four-wheel drive state are established. It is configured so that it can be switched to a driving state.

The second transmission shaft 14 is mounted on the partition wall 20 of the transmission case 17 on the first transmission shaft 12 side, and the end portion thereof is connected to the opening 1 on the other end side.
The transmission case 17 is pivoted on the support portion 20a of the mission case 17 so as to be in a cantilevered state facing the transmission case 8.

The gear type transmission mechanism 19 is constructed as shown in FIG.

That is, the transmission gear 23 is spline-fitted to the end of the second transmission shaft 14 in such a manner that it can be inserted and removed from one end of the second transmission shaft 14, and
Snap spring 27 for preventing the transmission gear 23 from coming off
is detachably attached to the second transmission shaft 14.

The rotary shaft 24 is removably supported in a case 21 that covers the opening 18, and a drive shaft 16a is separably connected to the front end of the rotary shaft 24 via a spline tube 22. A driven gear 25 that engages with the transmission gear 23 is disposed on the rear end side of the rotating shaft 24 of the front wheel drive shaft 16.
are removably spline-fitted.

The case 21 includes a rear end portion 21a that sandwiches the driven gear 25 and supports the rear end side of the rotary shaft 24 via a bearing as a bearing portion, and is integrally formed with the transmission case 17, and The front end side of the shaft 24 is supported via a bearing serving as a bearing portion. together with the rear end side portion 2
1a and a front end portion 21b detachably connected to the mission case 17 by bolts.

The opening 18 is located at the front end side case portion 21b.
By sliding the rotating shaft 24 and the driven gear 25 in the axial direction of the rotating shaft 24, the rotating shaft 24 and the driven gear 25 can be attached to and detached from the rear end case portion 21a together with the front end case portion 21b, and the transmission gear 23 can be attached to and removed from the transmission case portion 21a. 17 and the second power transmission shaft 14.

In short, when replacing the front wheels 1, 1 with larger or smaller diameter ones in order to increase the ground clearance of the vehicle body for work driving in wetlands or to improve maneuverability, it is necessary to As shown in FIG.
The front end case portion 21b is removed together with the rotating shaft 24 and the driven gear 25 from the transmission case 17 and the rear end case portion 21a, and the driven gear 25 is removed.
is removed from the rotating shaft 24, and the transmission gear 23 is removed from the opening 1.
8 from the second transmission shaft 14 and take it out from the transmission case 17, and assemble another transmission gear 23 and driven gear 25 with different transmission ratios in the reverse procedure to the above-mentioned case, and complete the gear type transmission mechanism. The transmission ratio at 19 is made to correspond to the change in the diameter of the front wheels 1, 1.

In summary, the present invention, in the above-mentioned front wheel drive structure of an agricultural tractor, attaches and detaches the transmission gear 23 attached to one end side of the front wheel transmission shaft 14 by operating from the opening 18, and One end side of the front wheel transmission shaft 14 is supported in a cantilevered state so as to face the opening 18 so that it can be taken in and taken out from the opening 18, and the rear end side of the front wheel drive shaft 16 is supported by the case 21. , the transmission gear 2
A driven gear 25 interlocked with gears is detachably attached to the case 21, and the case 21 is provided with a front end side portion 21b having a bearing portion that supports the transmission upper side of the front wheel drive shaft 16 by sandwiching the driven gear 25; The rear end portion 21a is divided into a rear end portion 21a provided with a bearing portion that supports the lower side of transmission of the front wheel drive shaft 16, and the rear end portion 21a is
is integrally configured with the mission case 17, and the front end side portion 21b is integrated with the mission case 1.
7 and the rear end side portion 21b in a detachable manner.

That is, one end side of the transmission shaft 14 faces the opening 18 in a cantilevered state, and the case 21 is integrated with the transmission case 17 at the rear end side portion 21a.
, the transmission case 17 and the rear end side portion 21a
Although it is a simple modification that consists of dividing the case 21 into a front end portion 21b and a front end portion 21b that can be attached and detached from the case 21, the front end portion 21b of the case 21 is removed and the transmission gear 23 and the driven gear 25 are replaced with other gears with different transmission ratios. Therefore, the transmission ratio in the gear type transmission mechanism 19 can be changed and adjusted without disassembling the transmission case 17.
Since it is only necessary to attach and detach b, the transmission ratio in the gear type transmission mechanism 19 can be easily changed and adjusted, and it can easily correspond to a change in the diameter of the front wheel.

In particular, in the present invention, since the rear end portion 21a of the case 21 is integrated with the transmission case 17, the front end portion 21b of the case 21 is integrated with the transmission case 17 and the rear end portion 21a together with the front wheel drive shaft 16. Just remove it from the driven gear 25.
The support by the case 21 for the front wheel drive shaft 16 on the rear side can be released, and after the entire case 21 is removed together with the front wheel drive shaft 16 as in the conventional case, the case 21 and the front wheel drive shaft 16 are removed. There is an effect that the driven gear 25 can be easily removed without the complicated work that would be required if the driven gear 25 is separated from the driven gear 16.

Furthermore, since the transmission case 17 that supports the front wheel transmission shaft 14 and the rear end side portion 21a of the case 21 that supports the rear end side of the front wheel drive shaft 16 are integrally constructed, the transmission gear 23 and the driven gear 2
When the case 21 is reassembled to the transmission case 17 after replacing the drive shaft 5, it is possible to very easily adjust the axial positions of the front wheel transmission shaft 14 and the front wheel drive shaft 16.

Note that although reference numerals are written in the claims section of the utility model registration for convenience of comparison with the drawings, the present invention is not limited to the structure of the attached drawings by such entry.

[Brief explanation of the drawing]

The drawings show an embodiment of the front wheel drive structure of an agricultural tractor according to the present invention, FIG. 1 is an overall side view of the agricultural tractor, FIG. 2 is a sectional view showing the wheel drive system,
FIG. 3 is a front cross-sectional view of the gear type transmission mechanism attachment part, FIG. 4 is an explanatory diagram showing how to attach and detach the gear, and FIG. 5 is a schematic diagram showing the conventional structure. 14... Front wheel transmission shaft, 16... Front wheel drive shaft, 17... Mission case, 18... Opening,
19...Gear type transmission mechanism, 21...Case, 21
a... Rear end side part, 21b... Front end side part, 23
... Transmission gear, 24 ... Rotating shaft, 25 ... Driven gear.

Claims (1)

[Scope of utility model registration request] An opening 18 is formed in the lower surface of the transmission case 17, and a case 21 that covers the opening 18 is provided in a position that projects downward from the transmission case 17. A front wheel transmission shaft 14 is supported within the transmission case 17. and a front wheel drive shaft 16 supported in the case 21 are interlocked and connected via a gear type transmission mechanism 19 that passes through the opening 18. , one end of the front wheel transmission shaft 14 is attached so that the transmission gear 23 attached to one end side of the front wheel transmission shaft 14 can be attached and detached by operation from the opening 18 and can be taken in and out from the opening 18. A front wheel drive shaft 1 is supported in a cantilevered state so as to face the opening 18, and is supported in the case 21.
A driven gear 25 interlocked with the transmission gear 23 is removably attached to the rear end side of 6, and the case 21 is mounted on a bearing that supports the transmission upper side of the front wheel drive shaft 16 by sandwiching the driven gear 25. The rear end portion 21a is divided into a front end portion 21b having a front end portion 21b and a rear end portion 21a having a bearing portion for supporting the lower transmission side of the front wheel drive shaft 16, and the rear end portion 21a is attached to the transmission case 17. The front end side portion 21 is integrally configured.
A structure for a front wheel drive unit of an agricultural tractor, characterized in that a drive unit b is detachably fixed to the transmission case 17 and the rear end side portion 21a.