Vehicle driving gear system

A driving gear system, suitable for use in connection with a vehicle having a three speed transmission, and for use in connection with a high-power vehicle having an adjustable track width, the vehicle including a differential gear system having first bearing means, features a bridge housing mounted on said vehicle, a first planetary gear system disposed in the bridge housing and including a first sun wheel, a plurality of first planet wheels, each having a first radius, and first supporting means operable for supporting the first planet wheels, a second planetary gear system disposed in the bridge housing and including a second sun wheel, a plurality of second planet wheels, each having a second radius, and second supporting means operable for supporting the second planet wheels and mounted for coaxial rotation with respect to the second sun wheel, the second radii being smaller than the first radii, the first bearing means being disposed in the first supporting means, housing shells connected to the bridge housing, connecting means operable for connecting the housing shells to a central portion of the bridge housing and for connecting the first supporting means to the bridge housing, the first sun wheel being mounted on a portion of the second supporting means for rotation therewith, and a second bearing means disposed between the first and second supporting means and operable to allow the rotation of the second supporting means relative to the first supporting means.

BACKGROUND OF THE INVENTION 
The invention relates to a driving gear system, suitable for use in 
connection with a vehicle having a three-speed transmission, and for use 
in connection with a high-power vehicle having an adjustable track width. 
Generally, it is desirable for the driving gear system to have the lowest 
possible net weight and load on the shaft and still provide the desired 
momentum safely throughout the projected working life. 
These requirements are of particular importance in the case of large heavy 
vehicles wherein engine performance with good efficiency such as in the 
case of a vehicle providing high tractional forces, is important and 
difficult to achieve. Such vehicles usually have two-speed transmissions 
in order to obtain the momentum levels. It is well known that the use of a 
three-speed transmission is advantageous from both a structural and 
technological point of view. The extremely high production costs for a 
driving gear system for use with a three-speed transmission can be reduced 
if elements which are usually suited for low power drives can be used and 
these elements can be produced economically in large quantities. 
From the prior art, it is known that a driving gear system for a 
three-speed transmission can take the form of two final momentum 
increasing stages which are arranged in the form of a cone-wheel and 
crown-wheel transmission using series connected, two planetary gears. It 
is known that for this arrangement, the driving gear system must be built 
from elements which, beginning from the main gear in the driving 
direction, must withstand increasing magnitudes in forces. This means that 
the elements increase in strength and therefore cost in the driving 
direction, away from the main gear. 
In the aforementioned vehicles, this does not present an insoluble problem 
because in arranging the planetary gears, the following possibilities are 
available: 
I. Both planetary gear systems can be arranged in the wheel hub which 
usually has extra space and can accommodate these gears; 
II. the planetary gear systems can be built into the bridge housing near 
the main drive; and 
III. one planetary gear system can be located near the main drive and the 
other planetary gear system of the last stage can extend into the wheel 
hub. 
The selection of the arrangement depends upon the requirements imposed on 
the driving gear system. 
Special vehicles such as prime movers or tractors include the capability of 
an adjustable track width. For such vehicles, it is preferable to have the 
planetary gear systems disposed in the bridge housing near the main drive. 
All other arrangements are considered to be generally impractical. 
Carrying out the solution presents problems because the space is limited in 
the bridge housing in order to accommodate the "narrow track" demand made 
by the suspension cushions which come close to one another in the 
longitudinal direction of the bridge housing. In addition, there is also 
the problem that the diameter of the planetary gear system cannot be 
increased arbitrarily because a vertical clearance is needed between the 
ground and the bridge housing. 
In the case of a vehicle with a three-speed transmission, the prior art 
uses a series connected, two planetary gear with the disadvantage of the 
external planetary gear having large dimensions. This results in the 
bridge housing taking on relatively large dimensions. 
As a result, the connection of the driving gear system to the chassis of 
the vehicle becomes extremely complicated and often results in the 
incorporation of considerably extra weight. 
The problem of extra weight is sufficiently serious to result in the prior 
art use of two-speed transmission for heavy vehicles having an adjustable 
track width, even though a three-speed transmission would be more 
desirable. Usually, the problem with these vehicles is essentially the 
difficulty in installing a planetary gear having the required diameter. 
Known examples of these prior art vehicles include vehicles manufactured 
by Massey-Ferguson and John Deere. 
It is the goal of the instant invention to eliminate the aforesaid 
disadvantages and thereby provide a driving gear system suitable for 
vehicles having a three speed transmission and vehicles having an 
adjustable track width in such a way that the dimensions of the bridge 
housing need not be disadvantageously changed. In addition, the instant 
invention endeavors to assure that the bridge housing has basically three 
conformations of the driving gear suspension cushions, so that the most 
favorable low net weight is obtained from both a structural and 
technological point of view for high-power driving gears. 
SUMMARY OF THE INVENTION 
One of the principle objects of the invention is a driving gear system, 
suitable for use in connection with a vehicle having a three-speed 
transmission, and for use in connection with a high-power vehicle having 
an adjustable track width, the vehicle including a differential gear 
system having first bearing means, the driving gear system including a 
bridge housing mounted on the vehicle, a first planetary gear system 
disposed in the bridge housing and including a first sun wheel, a 
plurality of first planet wheels, each having a first radius, and first 
supporting means operable for supporting the planet wheels, a second 
planetary gear system disposed in the bridge housing and including a 
second sun wheel, a plurality of second planet wheels, each having a 
second radius, and second supporting means operable for supporting the 
second planet wheels and mounted for coaxial rotation with respect to said 
second sun wheel, the second radii being smaller than the first radii, the 
first bearing means being disposed in the first supporting means, housing 
shells connected to the bridge housing, connecting means operable for 
connecting the housing shells to the central portion of the bridge housing 
and connecting the first supporting means to the bridge housing, the first 
sun wheel being mounted on a portion of the second supporting means for 
rotation therewith and second bearing means disposed between the first and 
second supporting means and operable to allow the rotation of the second 
supporting means relative to the first supporting means. 
Generally, the instant invention includes a double tandem power branched 
planetary system in a bridge housing in which, broadly speaking, the sun 
wheel of one planetary gear system is connected for rotation with the 
half-shaft branching from the differential gear system in which a toothed 
rim is directly connected with the driving half-shaft and the sun wheel of 
another planetary gear system adjoins the supporting means and, with the 
aid of toothed wheels rotating on stationary pins, drives an inner toothed 
rim which is connected with the driving half-shaft by means of the 
external toothed rim. 
It is also desirable to construct the driving gear so that it displays 
flanged driving half-shafts directly adjacent to the external toothed 
rims, and that the connection flange is made in one piece with the driving 
half-shaft. 
Furthermore, it is advantageous to construct the driving gear in such a 
manner so that loosely built-in external toothed rims which are 
self-adjustable to a limited extent and also self-adjustable loosely 
built-in inner toothed rim which directly adjoin the external toothed 
rims. 
It is believed that these technical solutions not only reduce the external 
dimensions of the driving gear system, but in addition, made possible the 
assembling of vehicles having adjustable track widths through the use of a 
few multi-purpose components which can be economically produced and also 
provide an overall reduction in weight; that is, the novel structure 
appears to achieve contradictory goals. 
The relatively small space of the instant driving gear system reduces the 
quantity of required oil and thereby reduces the operating costs. 
A further advantage is that one planetary gear system is of a lower order 
of magnitude than the dimensions of the other planetary gear system, so 
that the suspension-cushions can be connected in the same plane as the 
outer planetary gear system. 
The other planetary gear system which is a relatively "inner" position can 
be connected to a central portion of the bridge housing and thereby take 
up load forces on the conical roller bearings of the differential gear 
system. 
The driving half-shaft possesses an advantageous shape by providing an 
appropriate mounting of the necessary rigidity through the combination of 
the function of several components, so that the half-shaft is provided 
with a connecting flange for the purpose of assuring the direct connection 
with the external rim. 
The elimination of the detrimental effect of the forces acting on the 
planetary gear system is accomplished through the loose installation or 
limited self-adjustable coupling of the inner and external toothed rims 
with respect to one another as well as the connection of the driving 
half-shaft. Nevertheless, these interconnections are reliable and 
advantageous from the viewpoint of the transmission of power through the 
system. 
A buffer disc is connected to the frontal surface of the driving half-shaft 
in order to limit the axial displacement of the driving half-shaft and 
reduce problems concerning the supporting means in the planetary gear 
systems. 
Further objects and advantages of the invention will be set forth in the 
following specification and in part will be obvious therefrom without 
being specifically referred to, the same being realized and attained as 
pointed out in the claims hereof. 
The invention accordingly comprises features of construction, combination 
of elements, and arrangement of parts which will be exemplified in a 
construction hereinafter set forth and the scope of the application of 
which will be indicated in the claims.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
In carrying the invention into effect, certain embodiments have been 
selected for illustration in the accompanying drawings and the description 
in the specification, reference being had to FIGS. 1 and 2. 
It is well known in the art of the instant invention that the driving 
system for a vehicle is generally symmetrical so that an explanation of 
half of the system for a system is sufficient to describe the entire 
driving gear system. Furthermore, it is a practice to refer to a 
"half-shaft" with regard to the so-called half of the driving gear system. 
In this connection, it is pointed out that the instant invention has a 
possibility of being used as a two-fold system as indicated in FIGS. 1 and 
2 or a driving gear system corresponding to substantially half of that 
which is shown in FIGS. 1 and 2. 
Because of the symmetry of the systems shown in FIGS. 1 and 2, it is common 
practice to refer to a shaft on one side as being a "half-shaft". This 
prior art practice will be followed in the specification herein. 
The differential gear system 1 is coupled to the half-shaft 2 which drives 
the sun wheel 3 of a planetary gear system. The sun wheel 3 drives the 
externally toothed rim 7 by means of the planetary wheels 6 which are 
connected to the pins 5 mounted on the supporting means such as planetary 
carrier 4. 
The gear tooth system defined on the flange of the driving half-shaft 8 is 
connected in a loose self-adjustable manner to the toothed rim 7. A sun 
wheel 9 of another planetary gear system is connected to a projecting 
element of the planetary carrier 4 and drives the inner toothed rim 15 by 
means of planetary wheels 14. The planetary wheels 14 rotate on planetary 
pins 13. The planetary pins 13 are mounted on another supporting means 
such as planetary carrier 12 which, in turn, is connected by means of 
screws 11 to the middle portion 10 of the bridge housing. The toothed rim 
15 is connected to the gear tooth system formed on the flange of the 
toothed rim 7. 
A guide bearing 16 is mounted on a central bore hole of the planetary 
carrier 12 and guides the planetary carrier 4. Through a central bore hole 
in the planetary carrier 4, the driving half-shaft 2 is provided with a 
slot. The axial displacement of the planetary carrier 4 and the half-shaft 
2 is limited by a buffer disc 17 mounted on the frontal surface of the 
driving half-shaft 8. 
Clamping rings 18 including a threaded portion and bearings 19 are disposed 
in a central bore hole of the projected portion of the planetary carrier 
12 and cooperate for the mounting of the differential gear system 1 as 
well as for the adjustment of the bearing capacity of the gear toothed 
system of the bevel wheel and crown wheel of the differential gear system 
1, in accordance with the prior art practice. 
The screws 11 tightly retain the planetary carrier 12 and also fasten the 
bridge housing shells 20 to the middle portion 10. The housing shells 
include suspension cushions forming an integral part thereof. Due to the 
surprisingly small dimensions of the planetary gear system, including sun 
wheel 9, it is possible to form suspension cushions along a relatively 
long section above this planetary gear system in the vicinity of the 
housing shells 20 which is designated by A in FIG. 1. 
OPERATION 
The parallel connected planetary gear systems as disclosed herein operate 
in the following manner. 
The drive power of the half-shaft 2 is transferred to the sun wheel 3 and 
the drive power of the sun wheel 3 can be further transmitted to the rim 7 
through two paths. One path includes the planetary wheels 6 and the other 
path includes the planetary carrier 4, the sun wheel 9, and the planetary 
wheels 14 which couple to the toothed rim 15 and eventually to the rim 7. 
Thus, the two paths eventually come together at the rim 7, which is coupled 
to the half-shaft 8. 
From FIG. 1, it can be seen that the instant invention is suitable for a 
vehicle having three speed transmission or a vehicle having an adjustable 
track-width because of the power-branched planetary gear systems. The 
planetary gears have no adverse effect on the dimensions of the middle 
portion of the bridge housing, so that the suspension-cushions can be 
added freely. Furthermore, the form of construction of the instant 
invention is uniform and the components fulfill multiple tasks so that 
fewer gear systems, screw connections and accurate fittings are needed as 
compared to prior art systems. These advantages also reduce the weight and 
production costs for the instant invention. 
I wish it to be understood that I do not desire to be limited to the exact 
details of construction shown and described, for obvious modifications 
will occur to a person skilled in the art.