Claims:CLAIMS
We claim:
1. A drive shaft assembly (1000) comprising:
• a convoluted boot (104),
• a retainer ring (110) which is affixed with said convoluted boot (104),
• a tulip (108) and a spider assembly (100) with rollers,
• an articulation angle (?°) between 15° to 24°,
wherein the ratio of internal diameter of said retainer ring (ØDr)to the diameter of said tulip (ØDt) ranges from 0.74 to 0.80.
2. The drive shaft assembly (1000), as claimed in claim 1, wherein, thickness of said retainer ring (t) changes proportionately with the variation in diameter of said tulip (ØDt).
3. The drive shaft assembly (1000) as claimed in claim 1, wherein, thickness of said retainer ring (t) changes proportionately with the variation in diameter of said tulip (ØDt) in accordance to the relation:
change in thickness of said retainer ring (?t)=K*Change in diameter of said tulip(?ØDt),
wherein K has to be as low as 0.06.

, Description:FIELD OF INVENTION
The present invention relates to a drive shaft having boot-cap with an integrated retainer ring for a motor vehicle. More particularly, the present invention relates to drive shaft having boot-cap with integrated retainer ring for vehicles having a higher articulation angle.
BACKGROUND OF INVENTION
Most vehicles provide a drive train system for transmitting power from an engine to a plurality of rotatable driven wheels. A typical drive train system includes a clutch, a transmission, a drive shaft, and an axle connected between the engine and the driven wheels. The drive shaft is elongated so as to transmit the rotational power from the transmission to the vicinity of the driven wheels.
A typical drive shaft is an elongated cylindrical shaft that has tulip at one of its end which makes the housing arrangement for the spider assembly. Convoluted boots are placed over the tulip which protects the tulip and spider assembly form dirt, water, and other contaminants and also prevents grease leakage. In addition to the same, the boots are also designed such that it prevents the spider assembly from falling out of its place due to extreme road conditions.
It is observed that even though the spider assembly is well affixed inside the tulip and also protected by the convoluted boot, in extreme road conditions and due to unexpected jerking, the spider assembly falls out of its place, thereby resulting in complete failure of the driveshaft, which calls forth for its replacement. To avoid such conditions, it is preferred to provide a retainer ring inside the convoluted boot, which acts as an added protection for the spider assembly in extreme road conditions. More preferably, the retainer ring so provided should be such that it is integrated into a one piece structure with the boot to minimize the chances of failure.
In the prior art US20050082769, the convoluted boot in the driveshaft is provided with a retainer ring that is integrated with the boot to form a one piece structure. This increases the load retention capacity and thereby minimizes the chances of failure.
Even though the above design of integrated boot cap with retainer gives sufficient load retention capacity, one more factor to be looked into is the manner of the clamping. In cases of a vehicle with a higher articulation angle, the clamping parameters are to be minutely looked into to provide the maximum level of protection to the drive shaft assembly.
Hence, in light of the cited prior art and their limitations, there is a requirement of a drive shaft assembly with an improved design, which will be efficient as well as economical.
Thus the first objective of the present invention is to provide a drive shaft assembly, which helps in effective power transfer from the transmission to the wheels of a motor vehicle.
The second objective of the present invention is to provide better clamping ability of the convoluted boot in the drive shaft assembly with the tulip.
The third objective of the present invention is to provide the maximum strength requirement to the driveshaft assembly and prevent it from failure.
The final objective of the present invention is to have a drive shaft assembly which is economical and easy to manufacture.
BRIEF DESCRIPTION OF THE INVENTION
To achieve the above objectives, the present invention provides a drive shaft assembly which, for vehicles with a higher articulation angle. The convoluted boot in the drive shaft assembly is provided with a retainer ring which is integrated with the said convoluted boot, thus making it an integrated one piece structure. Moreover, the design of the retainer ring is made such that the diameter of the retainer ring is lower than the diameter of the tulip (and it varies within a specific range) and also its thickness varies with the variation in the diameter of tulip. This allows the drive shaft assembly to perform efficiently and also simultaneously provides retention to the spider assembly inside the tulip.
Although the subject matter has been described in considerable detail concerning certain preferred embodiments thereof, other embodiments are possible. As such, the spirit and scope of the appended claims should not be limited to the description of the preferred embodiment contained therein.

BRIEF DESCRIPTION OF THE DRAWINGS
Other aspects of the invention will become apparent by consideration of the accompanying drawings and their description stated below, which are merely illustrative of a preferred embodiment of the invention and do not limit in any way the nature and scope of the invention.
Figure 1a illustrates the perspective view of drive shaft assembly according to the present invention.
Figure 1b illustrates the perspective view of the convoluted boot according to the present invention.
Figure 2a illustrates the cross sectional view of the convoluted boot and tulip interface with the spider assembly inside the tulip when the articulation angle is 0° according to the present invention.
Figure 2b illustrates the cross sectional view of the convoluted boot and tulip interface with the spider assembly inside the tulip when articulation angle is ?° according to the present invention.
Figure 3 illustrates the view of the interface of the convoluted boot with the retainer and the tulip according to the present invention.
Figure 4 illustrates the view of the interface of the convoluted boot with retainer and the tulip and retainer ring thickness according to the present invention.
DETAILED DESCRIPTION OF THE DRAWINGS
The invention will now be described concerning the accompanying drawings which do not limit the scope and ambit of the invention. The description provided is purely by way of example and illustration.
The Figure 1a in the present invention shows the perspective view of drive shaft assembly (1000) which has tulip at both ends of the driveshaft assembly used specifically in higher articulation vehicles wherein articulation angle (?°) ranges between 15° to 24° for transmitting the rotational power from the transmission (not shown in the diagram) to the vicinity of the driven wheels (not shown in the diagram). The said tulip (108) comprises of spider assembly (100) with rollers seated inside the tulip (108). A convoluted boot (104) is fitted such that it covers the open end of said tulip (108). The convoluted boot (104), which is depicted in Figure 1b, comprises boot hub (112) and a metal retainer (110). The said boot hub (112), along with the retainer (110), is moulded into a single unit along with the boot (104) to form a one piece structure.
Figures 2a and 2b depict the spider assembly (100) housed inside the tulip (108). The central axis X-X is the reference line for the measurement of the articulation angle (?°). Figure 2a depicts the vehicle at resting condition, and hence the articulation angle (?°) is nil. Figure 2b shows the stage of vehicle in moving condition wherein the articulation angle (?°) increases from 0° to a value depending on the road conditions. The present invention is designed such that the articulation angle (?°) ranges from 15° to 24°, beyond which there is a failure in the drive shaft (106).
Figure 3, in the present invention, shows the interface of the convoluted boot (104) with the retainer ring (110) affixed inside the boot hub (112) and the tulip (108). The inner diameter of the retainer ring (110) is marked as ØDr and the diameter of the tulip as ØDt. In the given design, the retainer ring (110) is made such that its inner diameter and the diameter of the tulip (ØDt) makes the ratio of inner diameter of retainer ring (ØDr) to the diameter of tulip (ØDt) fall within the value of 0.74 to 0.80 which makes it an optimal design, allowing the drive shaft (106) to efficiently function at higher degree of articulation and also retains the spider assembly (100) inside the tulip (108) in case of higher pull out load exerted due to extreme road conditions.
The thickness of the retainer ring (t) is given in Figure 4, which varies proportionately with the diameter of the tulip (ØDt). With the increase in diameter of the tulip (ØDt), the thickness of the retainer ring (t) will also increase to be able to bear the roller assembly pull out load and accommodate the same.
The technical advancements offered by the present disclosure include:
• The present invention results in better packaging of spider assembly inside the axial sliding internal profile of the tulip.
• Due to the fixing of the range of retainer ring dimensions, product failure at a higher degree of articulation is prevented.
• The said dimensions provide better protection to the spider assembly and prevent it from falling off in cases of pull out axial load exerted due to extreme road conditions.
• The unpredicted lateral force coming to the vehicle can be accommodated by the present design as provided.
While considerable emphasis has been placed herein on the specific features of the preferred embodiment, it will be appreciated that many additional features can be added and that many changes can be made in the preferred embodiment without departing from the principles of the disclosure. These and other changes in the preferred embodiment of the disclosure will be apparent to those skilled in the art from the disclosure herein, whereby it is to be distinctly understood that the preceding descriptive matter is to be interpreted merely as illustrative of the disclosure and not as a limitation.

LIST OF REFERENCE NUMERAL

100-Spider assembly
104-Convoluted Boot
106-Drive Shaft
108-Tulip
110-Retainer Ring
112-Boot Hub
ØDr-Internal Diameter of Retainer
ØDt-Diameter of Tulip
?°-Articulation Angle
t-Thickness of Retainer ring
1000-Drive Shaft Assembly