FORM 2
THE PATENT ACT 1970
(39 of 1970)
&
The Patents Rules, 2003
PROVISIONAL SPECIFICATION
(See section 10 and rule 13)


1. TITLE OF THE INVENTION AXLE WITH REMOVABLE FLANGE
2- APPLICANT
MAHINDRA & MAHINDRA LTD.
1, GATEWAY BUILDING, APOLLO BUNDER, MUMBAI - 400001.
AN INDIAN COMPANY.
The following specification describes the invention.


3 1 MAR 2009

Field of the Invention
The present invention in general relates to an axle assembly for vehicles, and particularly, to an assembly having an axle shaft with removable flange and disposition of oil seal therewith to facilitate convenient service and maintenance.
Background of the Invention
Conventionally, axle assemblies are provided with integral axle shaft and flange either by forging method or by welding process. By doing so, occurrence of failure to any of the components leads to replacement of entire component and which further leads to high cost of maintenance, time consuming and tedious serviceability.
Further to above mentioned problem, particularly those vehicles operating under dusty environment and farm lands causes the oil seal provided in the axle housing to failure frequently. So, it needs to be replaced very frequently to avoid leakage of oil outside the housing and restrict the flow of dust particle inside the housing thereby to increase the reliability of the axle housing assembly. In integral axle shaft and flange assembly, replacement of oil seal becomes a tedious and time consuming process by way of removing the entire axle housing assembly from the vehicles. To overcome aforementioned problems different proposal of separating the axle shaft and flange has been made. Some of them are being described hereunder as prior art for our present invention.
31 MAR 2009

US patent 4135766 discloses a high performance rear axle assembly comprising a separable wheel-mounting flange and axle. The flange is fabricated of alloy steel highly resistant to bending stress and the axle is of different alloy steel more highly resistant to torsional stress. The flange is splined onto the axle shaft by a cone interfitting the flange hub. According to this invention, apart from separating the flange and axle shaft for providing different alloy steel for the fabrication thereof, it does not mention about the oil seal or the provision thereof in the construction. Even if it is provided in the construction, it will require dismantling of entire axle assembly to replace the oil seal.
US Patent 6254196 discloses a full floating inverted axle assembly having a removable axle shaft includes an inner race rigidly connected to a wheel body and rotatably connected to an outer race which is in turn rigidly connected to an axle housing to enable rotation of the wheel body relative to the axle housing. The removable axle shaft is externally removable from the entire axle assembly when the hub assembly is connected to the axle housing. An oil seal is disposed between the inner race and outer race adjacent an external end to contain lubrication fluid within the axle assembly. However, according to above invention, for the application of farm machineries such as tractor, frequent replacing of oil seal makes the serviceability a tiresome process by way of removing entire hub assembly from the rear axle and dismantling the inner race and outer race are even more time consuming process also axle shaft is fully floating type and shaft can take only torsional load.
US Patent 5603554 shows a rear axle assembly having a rear axle extending lengthwise within an elongated rear axle tube and a wheel
31 MAR 2009

hub mounted on the axle for rotation as a unit therewith. The wheel hub is mounted on the rear axle via a bearing, rigidly connecting inner race and outer race thereof with the wheel hub and axle tube respectively. The wheel hub and bearings are directly mounted on the axle tube thus all bending load is transformed to axle tube. Even though, the invention is of separable flange and axle assembly, it does not give the provision for oil seal which is most desirable in the case of vehicles working in farm lands. Even if provision is given for oil seal, hub assembly along with bearing is to be removed for oil seal replacement.
Hence, to overcome the shortcomings and disadvantages mentioned in the prior art and, further to that to meet our requirement, a proposal has been made for a driver axle assembly having an axle shaft provided with spline at the outer end and a flange having axially extended portion adapted to receive oil seal on the outer surface thereof. The axle shaft is supported in the axle housing via two bearing.support to withstand the vehicle load and the flange is splined onto the axle shaft in such a way to receive the oil seal thereby to make the serviceability, maintenance and replacement of oil seal becomes more easier just by dismantling the flange from the axle shaft.
It was also decided to have a robust axle assembly by integrating the axle shaft with planetary gear assembly with various constructions, which will be apparent from the detailed description, indicated as other embodiments, along with corresponding drawings to those skilled in the art.
3 1 MAR 2009

Object of the Invention
The present invention overcomes the shortcomings associated with the prior art and achieves other advantages not realized by the prior art.
The main object of the invention is to provide a drive axle assembly in such a way that oil seal can be replaced with much ease without disturbing the drive axle assembly as well as in short period of time.
Another object of the invention is to reduce complexity in manufacturing and/or in machining the axle shaft and the flange.
Yet another object of the invention is to limit the transfer of stress from flange to axle shaft thereby to increase reliability of the drive axle shaft.
Summary of the Invention
In one aspect thereof, the present invention provides a drive axle assembly, comprising;
an axle shaft to transfer the drive from differential to wheel, a flange to mount wheel and an axle housing for supporting the axle shaft via bearings at outer end and inner end thereof,
wherein,
the outer end of the axle shaft is provided with a spline section and a
threaded hole adapted to engage with a bolt to hold the flange via a
nut,
3 1 MAR 2009

and wherein,
the flange is provided with spline centrally adapted to engage with the axle shaft spline and provision for mounting wheel via bolts also an extended portion which is being extended axially inward so as to supported on surface of axle shaft and to confront outer surface with oil seal inner surface, which is secured in the retainer provided at outer end of the axle housing.
In another aspect thereof, the present invention provides a drive axle assembly in which the inner end of the axle shaft is integrated with carrier plate thereupon with planetary pin of planetary gear assembly.
In yet another embodiment thereof, the present invention provides a drive axle assembly in which the inner end of the axle shaft is splined onto the carrier plate of planetary assembly.
Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.
Brief Description of the Drawings:
Further features and advantages of the present invention, as well as the structure and operation of various embodiments of the present
3 1 MAR 2009

invention, are described in detail below with reference to the accompanying drawings.
FIG. 1 is cut section of drive axle assembly in assembled condition
showing the present invention. FIG. 2 is cut section of another embodiment of the present invention
with reference to FIG. 1 FIG. 3 is cut section of yet another embodiment of the present
invention with reference to FIG. 1
Detailed Description of the Preferred Embodiment
According to present invention, with referring to FIG.l, comprises an axle shaft 2 having spline section 9 at the end outwardly thereof and an axle housing 3 to support the axle shaft 2 via bearings 4 towards on both ends of said axle shaft 2. Outer end of the axle housing 3 is designed in such a way to adapt retainer in assembled position thereby to secure a oil seal 7 therein. Said axle shaft 2 is provided with a threaded hole at the outer end thereof towards inwardly along the line of axis of axle shaft 2.
The drive axle assembly, according to the present invention, also comprises a removable flange 1 for the purpose of mounting wheel (not shown) via bolts through a provision 11 given circumferentially outward thereof and provided with spline section, centrally, adapted to engage with the outer spline section 9 of the axle shaft 2. Said flange 1 is also provide with an extended portion 8 which is being extended axially from the inward surface thereof. The inner circumferential surface of the extended portion 8 is adapted to be supported on
3 1 MAR Z009

radially extended surface 12 of the axle shaft 2 and outer circumferential surface is adapted to congruent with the oil seal 7 secured in the retainer, which is provided on outer end of the axle housing 3. After the flange 1 is engaged with the axle shaft 2 via spline, a nut 5 is adjustably disposed on the outer end of the axle shaft 2 with the help of a bolt 6 that is threaded onto the hole 13 thereby to make the adjustment of the flange 1, axially. Locking means (not shown) is provided to prevent the loosening of nut during operations. The intersection of the flange 1 and the extended portion 8 is sufficiently provided with fillet so as to receive only bending load, when the axle torque is transmitted to flange through spline thereby to result in high reliability of the drive axle assembly, thus the oil seal 7 which is secured in the retainer 10 can be easily replaced by removing the flange thereby to enable easy replacement of oil seal without dissembling the entire Rear Axle assembly.
In cases, where a planetary reduction is provided in drive axle assembly before the axle shaft, other embodiments of the present invention are being described, accordingly, in detail along with figures hereinafter:
Referring now to FIG. 2, a drive axle assembly is having a removable flange A and an axle shaft B, which are being constructed as described above with reference to FIG. 1. The inner end of the axle shaft B is provided with spline section which is being engaged with another spline section provided on carrier plate C, which further support planetary carrier pin to carry planetary gear. Planetary carrier C is adjustably connected to the axle shaft with the help of bolt and nut.
31 M4R ?009

Referring now to FIG. 3, a drive axle assembly is having a removable flange A and an axle shaft B, which are being constructed as described above with reference to FIG. 1. The inner end of the axle shaft B is integrated with a carrier plate C, which act as a support for planetary
carrier pin to carry planetary gear.
In the above cases, it is possible to employ one piece axle shaft as per the prior art to construct the present axle shaft by disposing the axle shaft in 180 degree from the known system thereby making use of the same design, as used for the engagement of the planetary carrier plate, for the engagement of the flange also.
Dated 30th day of March 2009

Shyam Sunder Iyer Patent Agent
To,
The Controller of Patents
The Patent Office at Mumbai.
3 1 MAR 2009