JPH0249145Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field This invention relates to a front wheel drive device for a tractor that uses a planetary gear reduction device as the final reduction device.

Conventional technology Conventionally, in tractors that drive the rear wheels and also drive the front wheels, which are steering wheels, the reduction mechanism is made smaller by using a planetary gear reduction device as the final reduction device for the front wheels. At the same time, it becomes possible to increase the reduction ratio. and,
Examples of devices that use a planetary gear reduction device as the final reduction device for the front wheels include Japanese Patent Publication No. 61-2525, Japanese Patent Application Laid-open No. 58-139821, Japanese Patent Application Publication No. 59-213522, and Japanese Patent Application Laid-open No. 60-29335. Publication, Utility Model No. 57-165519
There are those described in Japanese Utility Model Publication No. 57-200436, etc.

Problems to be solved by the invention In the systems described in Japanese Patent Publication No. 61-2525, Japanese Patent Application Laid-open No. 60-29335, and Japanese Utility Model Application No. 57-200436, the internal gear has an inner case and an outer case. It is held between. Therefore, there are disadvantages in that the number of mating surfaces increases, oil leakage is likely to occur, and the strength against loads is reduced.

In the devices described in JP-A-58-139821, JP-A-59-213522, and JP-U-57-165519, the internal gear is tightened and fixed to the inner case or outer case. Although there is no increase in the mating surface, a tightening surface for the internal gear is required inside. For this reason, the axle case consisting of the inner case and the outer case becomes larger in the vertical direction, and the area of the mating surfaces becomes larger, resulting in a reduction in sealing performance.

This invention has been made in view of the above points, and an object thereof is to obtain a front wheel drive device for a tractor that can reduce the size of the axle case and improve the strength.

Means for Solving the Problems A planetary gear reduction device is housed within an axle case consisting of an inner case and an outer case fixedly connected to an outer opening of the inner case. An internal gear forming a part of the planetary gear reduction device is integrally formed on the inner peripheral surface of the outer case.

Function The axle case that houses the planetary gear reduction device is constructed by connecting the inner case and the outer case, and there are few mating surfaces, which prevents oil leaks and improves strength against loads. do.
The internal gear that forms part of the planetary gear reduction device is integrally formed on the inner circumferential surface of the outer case, reducing the installation space for the internal gear and making the axle case more compact.

Embodiment An embodiment of this invention will be described based on the drawings. A front wheel differential case 3 is supported on a front wheel support 2 fixed to the front part of the tractor body 1 so as to be able to swing freely about an axis in the longitudinal direction.
is fixed. A transmission case 5 is fixed to the outer end of the axle case 4, and an axle case 8 is connected to the transmission case 5 so as to be rotatable about the axes of an upper kingpin 6 as a kingpin and a lower kingpin 7 as a kingpin. ing. Note that the axle case 8 is divided into an inner case 9 and an outer case 10, and the inner case 9 is connected to the transmission case 5.
The outer case 10 is fastened to the outer opening of the inner case 9 with bolts 11 and pins 12.

A front wheel drive shaft 13 is held in the axle case 4 so as to be rotatable around the axis, and the inner end of the front wheel drive shaft 13 is connected to a differential device (not shown) installed inside the front wheel differential case 3. A bevel gear 14 located inside the transmission case 5 is spline-fitted to the outer end of the front wheel drive shaft 13 .

Next, a transmission shaft 17 whose upper end is pivotally supported by the transmission case 5 via a bearing 15 and whose lower end is pivotally supported by the axle case 8 via a bearing 16 is aligned with the axis of the king pins 6 and 7. They are provided to be freely rotatable around the same axes in the vertical direction. Bevel gears 18 and 19 are spline-fitted to both upper and lower ends of the transmission shaft 17, with the upper bevel gear 18 meshing with the bevel gear 14, and the lower bevel gear 19 meshing with a bevel gear described later.

Inside the axle case 8, a planetary gear reduction device 20 serving as a final reduction device, an axle 21, and a bevel gear 22 that meshes with the bevel gear 19 are installed.
3, a carrier 24, a planetary gear 25, and an internal gear 26. First, the internal gear 26 is integrally formed on the inner peripheral surface of the outer case 10, and the carrier 24 is integrally formed with the axle 21. Next, the bevel gear 22 is pivotally supported by the inner case 9 and the carrier 24 via bearings 27 and 28,
Further, one end of the sun gear 23 is spline-fitted to the center of the bevel gear 22 in a cantilevered state. A plurality of pins 29 having an axis parallel to the axis of the sun gear 23 are arranged and fixed at a predetermined interval on the same circumference on the outer periphery of the carrier 24. The planetary gear 25 is rotatably supported via a needle bearing 30. These planetary gears 25 mesh with the sun gear 23 and the internal gear 26.

The carrier 24 is rotatably supported by the inner case 9 and the outer case 10 via bearings 31 and 32. The bearing 31 is joined to a notch 33 formed at the end of the pin 29 to prevent the pin 29 from rotating.Furthermore, the bearing 32 pivotally supports the carrier 24 and is attached to the axle 21 externally. A front wheel mounting flange 34 fitted with a spline is also pivotally supported at the same time. An oil seal 35 is interposed between the front wheel mounting flange 34 and the outer case 10, and the front wheel mounting flange 34 is connected to the axle 21 by a plate 36 and bolts 37.
It is fixed to prevent it from coming out. Further, a wheel disk 38, which is a part of the front wheel, is attached to the outer peripheral portion of the front wheel mounting flange 34.

In such a configuration, the rotation of the front wheel drive shaft 13 due to the driving force from the engine is controlled by the bevel gear 14.
The signal is transmitted from the power transmission shaft 17 to the bevel gear 18 , and further transmitted from the power transmission shaft 17 to the bevel gear 22 via the bevel gear 19 . A sun gear 23 rotates together with the bevel gear 22, and a planetary gear 25 meshes with the sun gear 23 and internal gear 26.
The carrier 24 rotates around the axis of the pin 29.
It also revolves around the sun gear 23. Then, the axle 21, which is integral with the carrier 24, rotates about its axis, and the driving force is transmitted to the front wheels.

Here, since the planetary gear reduction device 20 is used as the final reduction device, the reduction ratio can be increased without increasing the diameter of the bevel gear 22, and the axle case 8 can be made smaller.

Next, the axle case 8 is made by connecting an inner case 9 and an outer case 10, and there are few mating surfaces in the axle case 8. Therefore, the sealing performance at the mating surfaces is improved, oil leakage from the mating surfaces is prevented, and the strength of the axle case 8 against loads is improved. Furthermore, since the internal gear 26 is integrally formed on the inner peripheral surface of the outer case 10, the space required within the axle case 8 is reduced compared to when the internal gear 26 is formed separately and assembled. be done. For this reason, the axle case 8 is further downsized, and the area of the mating surface between the inner case 9 and the outer case 10 is reduced due to the further downsizing of the axle case 8, so that the sealing performance at this mating surface is improved. Improve even further.

Effects of the invention This invention can reduce the number of mating surfaces in the axle case by connecting the outer case to the opening of the inner case to form the axle case as described above. It is possible to improve the sealing performance on the mating surfaces and prevent oil leakage from the mating surfaces, and also to improve the strength of the axle case. Since it is integrally formed on the inner circumferential surface of the outer case, it has the effect of reducing the installation space for the internal gear and further downsizing the axle case.

[Brief explanation of the drawing]

The drawing shows one embodiment of this invention.
The figure is a longitudinal sectional front view of the axle case portion, and FIG. 2 is a front view of the entire tractor. 4... Axle case, 6... Upper king pin (king pin), 7... Lower king pin (king pin), 8... Axle case, 9... Inner case, 1
0... Outer case, 13... Front wheel drive shaft, 20...
... Planetary gear reduction device, 21 ... Axle, 26 ... Internal gear.

Claims (1)

[Scope of utility model registration request] An inner case is connected to the outer end of an axle case housing a front wheel drive shaft so as to be rotatable around the axis of a king pin having a substantially vertical axis, and an outer case is connected to an outer opening of the inner case. A planetary gear reduction device that is fixedly connected to the front wheel drive shaft and an axle to which the front wheels are attached is housed in an axle case consisting of an inner case and an outer case, and one of the planetary gear reduction devices 1. A front wheel drive device for a tractor, characterized in that an internal gear forming a part of the outer case is integrally formed on an inner circumferential surface of the outer case.