DESC:FORM 2
The Patent Act 1970
(39 of 1970)
&
The Patent Rules, 2005

COMPLETE SPECIFICATION
(See Section 10 and Rule 13)

TITLE OF THE INVENTION
“HALFSHAFT ASSEMBLY FOR A VEHICLE”

Endurance Technologies Limited
E-92, M.I.D.C. Industrial Area, Waluj,
Aurangabad – 431136, Maharashtra, India

The following specification particularly describes and ascertains the nature of this invention and the manner in which it is to be performed.
Field of Invention

[001] The present invention is related to a halfshaft assembly for a vehicle. More particularly the invention is to provide a halfshaft assembly with improved the durability that minimizes backlash error and drastically reduce the maintenance of the halfshaft assembly in vehicles with rear mounted engines and rear wheel drive that are subjected to higher articulation angles.

Background of the Invention

[002] Halfshaft is a vital component for transmitting power from engine to wheel which rotates at around 2000 – 3000 rpm particularly in rear wheel drive vehicles. It transmits the power from engine to wheels. Halfshaft must operate through continuously changing angles as per the road conditions between the Transmission and Wheel hub assembly.

[003] Conventionally available halfshaft, particularly for rear drive vehicles, has tulip at each of its ends which makes the housing arrangement for the spider assembly. The convoluted boots are placed over the tulip which protects the tulip and spider assembly from dirt, water, and other contaminants and also prevents grease leakage. This joint works with three rollers to transmit the rotations from the input to the output. In such designs three rollers are mounted on a spider legs. There is a slide fit between rollers and spider legs. This slide fit allows rollers to rotate very freely on spider legs. This spider assembly fits inside the mouth with three matching pockets, which is integrated with a flange and shaft. This pocket allows the joint to operate at an angle, but it also allows axial movement in the pocket without sacrificing drive.

[004] But this conventional design has limitation for the higher articulation angle. It cannot have length flexibility by changing any single part. It works on the dynamic contact between parts which creates backlash and this backlash is the major concern for early wear out of child components. Further, this design has complicated structure to transfer torque under the angles with flexibility and articulation. Additionally, this design requires the grease at both sides of flanges for the smooth functioning of the spider and roller and dissipation of the heat generated due to friction. The grease being a serviceable parameter, needs to replace at regular intervals requiring replacement of large clamps with hubs at both sides which consequently leads to high maintenance cost. In addition, to hold the boots in proper and fixed location, it require specialized clamps calling for additional cost as the replacement of clamps is a costly affair.

[005] Hence, there is a long pending and unmet requirement of a product that addresses the drawbacks of the conventional designs of the driveshaft and provide simple, economic and maintenance free solution. The present invention as described below fulfils the requirement.

Objectives of the Invention

[006] The main objective of the present invention is to provide a halfshaft assembly for a vehicle.

[007] Another objective of the present invention is to provide a halfshaft assembly for a vehicle that works under higher articulation angles.

[008] Further, the objective of the present invention is to provide a halfshaft assembly for a vehicle wherein said halfshaft assembly comprises a shaft and a pair of muff cups / flanges wherein said muff cup/flange is configured to have four equi-spaced uniquely profiled pockets on its inner surface to accommodate the bipod and rollers assembly.

[009] The objective of the present invention is to provide a halfshaft assembly for a vehicle wherein a roller is mounted on each of the legs of bipod and a snap ring is provided to restrict the movement of roller.

[0010] Yet, the objective of the present invention is to provide a halfshaft assembly for a vehicle wherein the muff cup side mounting is structured in such a way that there is minimum contact of metal and boot during different articulation angles addressing the issue of wear and tear of the assembly.

[0011] Still another objective of the present invention is to provide a halfshaft assembly for a vehicle that improves product durability and minimizes backlash error.

[0012] Yet the objective of the present invention is to provide a halfshaft assembly for a vehicle that improves product durability with improved strengthening and drastically reduces the maintenance and the cost associated with it.

[0013] Further, the objective of the present invention is to provide a half shaft assembly for a vehicle that is very simple in construction and require no specialized manufacturing processes and materials.

Brief Description of the Drawings

[0014] This invention is illustrated in the accompanying drawings, throughout which like reference letters indicate corresponding parts in the various figures. The embodiment/s herein and advantages thereof will be better understood from the following description when read in conjunction with the following drawings, wherein

[0015] Figure 1 discloses perspective view of the halfshaft assembly in accordance with the present invention

[0016] Figure 2 shows the views of muff cup / flange wherein said muff cups/flange is configured to have four equi-spaced uniquely profiled pockets on its inner surface as per the present invention.

[0017] Figure 3 shows the bipod and rollers assembly attached with the shaft of the halfshaft assembly of the present invention.

[0018] Figure 4 presents the bipod and rollers assembly mounted within the equi-spaced uniquely profiled pockets of muff cup/flange as per the present invention.

[0019] Figure 5a shows magnified view of bipod pin, roller and snap ring and Figure 5b shows the cut view of its assembly in accordance with the present invention.

[0020] Figure 6 shows the cut view of the halfshaft assembly as per the present invention.

[0021] Figure 7 discloses sectional view of the halfshaft assembly as per the present invention.

Detailed Description of the Present Invention

[0022] Referring to Figs. 1, 6 and 7, a halfshaft assembly (100) for a rear engine mounted and rear wheel drive vehicle comprises of a shaft (10), a pair of muff cups / flanges (12, 28), a pair of bellows (14), a pair of bipod pin (16), a plurality of rollers (20), a plurality of snap rings (22) and a plurality of metal clips (24 and 26). In the pair of muff cups / flange (12, 28), one of the muff cup / flange (12) is transmission side flange and the other muff cup / flange (28) is a wheel flange. The shaft (10) has a circular cross section throughout its length and it has two ends (10a and 10b). Both ends of the shaft (10) are configured to have a ball shaped profile (18) with a thorough opening (30) therein to accommodate the bipod pin (16).

[0023] Referring to Fig. 5a, the bipod pin (16) is configured to have main body portion (16M) and leg portions (16a and 16b) formed on either sides of the main body portion (16M) through a stepped profile (16T). Each of the legs (16a and 16b) of the bipod pin (16) is configured to have a groove (16G) at its distal end and the said groove (16G) houses a snap ring (22) in such way that it locks the roller (20) over the legs of the bipod pin (16). The roller (20) is configured to have a stepped profile (20T) at its inner top portion and said stepped profile (20T) works as the base for the snap ring (22) to have positive locking of the roller (20) with the legs (16a and 16b) of the bipod pin (16).

[0024] Referring to Figs. 3, 5b and 6, the bipod pin (16) is press fitted in the opening (30) of the ball shaped profile (18) provided at either ends of the shaft (10). The fitting of the bipod pin (16) is done in the ball shaped profile (18) in such way that the legs (16a and 16b) of the bipod pin (16) are projected out from both sides of the opening (30) of the ball shaped profile (18). The roller (20) is mounted on the projected legs (16a and 16b) of the bipod pin (16) and is locked there with the help of snap ring (22) in such way that the snap ring (22) restricts the axial movement of roller (20). The placement of the snap ring (22) to lock the roller (20) with the bipod pin (16) is such that the half sectional portion of the snap ring (22) is within the groove (16G) of the legs (16a and 16b) of the bipod pin (16) and rest of the sectional portion of the snap ring (22) rests in the stepped profile (20T) of the roller (20) thereby imparting positive locking of the roller (20) with the bipod pin (16) as shown in Fig. 5b.

[0025] Referring to Fig. 2, the muff cups/flange (12 and 28) is configured to have four equi-spaced uniquely profiled pockets (40) on its inner surface to accommodate the bipod pin and rollers assembly. The shaft (10) fitted with bipod pin (16) and said bipod pin (16) fitted with a roller (20) on each one of its legs (16a and 16b) and locked there with snap rings (22) is mounted in a pair oppositely profiled pockets (40) structured on the inner surface of the muff cup / flange (12, 28). The muff cup side mounting is structured in such a way that there is minimum contact of metal (i.e. the metal of the flange (12, 28) or of the shaft (10)) and boot / bellow (14) during different articulation angles addressing the issue of wear and tear of the bellow (14).

[0026] One end (10a) of the shaft (10) fitted with a bipod pin (16), a pair of rollers (20) and a pair of snap rings (22) is mounted inside the pair oppositely profiled pockets (40) structured on the inner surface of the muff cup / flange (12), and the other end (10b) of the shaft (10) fitted with a bipod pin (16), a pair of rollers (20) and a pair of snap ring (22) is mounted inside the pair oppositely profiled pockets (40) structured on the inner surface of the muff cup / flange (28). The joinery of the shaft (10) at its both ends with the muff cup / flange (14, 28) is covered with the rubber bellow (14). The bellow (14) is configured to have a shaft end (14a) and a flange end (14b); and the shaft end (14a) is has its diameter smaller than that of the diameter of the flange end (14b). The shaft end (14a) of the rubber bellow (14) is inserted on the shaft (10) and fitted there tightly with the help of the metal clip (26). The other end (14b) of the rubber bellow (14) is inserted on the muff cup / flange (14, 28) and fitted there tightly with the help of the metal clip (24) as shown in Fig. 6. The muff cup / flange is filled with the grease to facilitate lubrication to bipod pin and roller assembly. The bellow (14) restrict the entry of any foreign material, mud, dirt, etc. to enter in the muff cup / flange (14, 28).

[0027] The unique construction of the halfshaft assembly of the invention comprising a pair of muff cups / flange (14, 28) configured to have four equi-spaced uniquely profiled pockets (40) on its inner surface to accommodate the bipod pin (16) and rollers (20) assembly; a roller (20) mounted on each of the legs (16a and 16b) of bipod pin (16) and a snap ring (22) intelligently placed to lock and restrict the axial movement of the roller (20); and the shaft (10) fitted with bipod pin (16) and bipod pin fitted with two rollers (20) and snap rings (22) mounted in a pair oppositely profiled pockets (40) structured in muff cup / flange (14, 28) improves the torque transmission efficiency and reduces backlash error as per the vehicle requirement.

[0028] As far as the working of this invention is concerned, when the vehicle with rear mounted engine and rear wheel drive runs on the road surface, the transmission output shaft center and wheel center are in the different planes. In this condition, to transmit the torque efficiently from transmission output shaft to wheel hub, the uniquely structured bipod pin and roller assembly of the halfshaft assembly of the invention slides intelligently within the uniquely profiled pockets provided on the inner surface of the muff cup / flange and facilitate the transfer of torque without any backlash error and improved articulation angle. In this invention backlash error is addressed by maintaining the limited but required contact area between the outer peripheral surface of the roller and the inner profiled surface of the muff cup / flange. This is achieved by rolling and sliding movement of the rollers within the profiled pockets (40) of the muff cup / flange. Metal clips (24, 26) rigidly locks the position of the bellow on the muff cup / flange and the shaft (10) thereby eliminating the entry of any foreign material inside the muff cup.

[0029] The technical advantages achieved by the embodiments of the present invention and thereby the inventive contribution to the technology domain of the halfshaft assembly are as under:
- It achieves higher articulation angles and improves product durability.
- Facilitate for higher torque and load taking capacity and minimizes the backlash error.
- The embodiment of the invention efficiently transfer the torque and provides maintenance free product.
- The requirement of bellow hub, retainer ring, spider roller units, springs, etc. (as is required in the conventional units) is totally eliminated thereby leading to reduction in weight and cost of the halfshaft assembly.
- The embodiment of the invention is very much effective in the vehicles that are operated on the undulating road surfaces (specifically on the roads in rural areas) where more articulation angle is required due to uneven road surfaces for efficiently transfer of the torque.
- The embodiment of the invention has wide applications in defence vehicles and vehicles that operate in higher altitude terrains with off-road applications. The embodiment facilitate to offer a higher ground clearance.
- The invention provides very simple and easy to manufacture halfshaft assembly that drastically reduces wear out of child parts.
- It does not require any of the specialized processes of manufacturing, heat treatment and finishing.
- The design of the embodiments leads to significant reduction of weight thereby improving the vehicle fuel efficiency and drivability.

[0030] The foregoing description of the specific embodiment of the invention will so fully reveal the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiment. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the embodiment herein has been described in terms of preferred embodiment, those skilled in the art will recognize that the embodiment herein can be practiced with modification within the spirit and scope of the embodiment as described herein.
,CLAIMS:We Claim

1. A halfshaft assembly (100) for a vehicle, the vehicle with rear mounted engines and rear wheel drive, comprising of a shaft (10), a pair of muff cups / flanges (12, 28), a pair of bellows (14), a pair of bipod pin (16), a plurality of rollers (20), a plurality of snap rings (22) and a plurality of metal clips (24 and 26);
wherein,
- the shaft (10) has ends (10a and 10b) and each of the ends of the shaft (10) is configured to have a ball shaped profile (18) with the thorough opening (30) therein to accommodate the bipod pin (16);
- the bipod pin (16) is press fitted in the opening (30) of the ball shaped profile (18) provided at either ends (10a and 10b) of the shaft (10) such that the legs (16a and 16b) of the bipod pin (16) are projected out from both sides of the opening (30) of the ball shaped profile (18);
- the roller (20) is mounted on the projected legs (16a and 16b) of the bipod pin (16) and is locked there with the help of snap ring (22) restricting the axial movement of roller (20);
- the bellow (14) is configured to have a shaft end (14a) and a flange end (14b); and
- the joinery of the shaft (10) at its both ends (10a and 10b) with the muff cup / flange (12, 28) is covered with the rubber bellow (14) by inserting the shaft end (14a) and the flange end (14b) of the rubber bellow (14) over the shaft (10) and the muff cup / flange (12, 28), respectively.

2. The halfshaft assembly (100) as claimed in claim 1, wherein the muff cups/flange (12 and 28) is configured to have four equi-spaced uniquely profiled pockets (40) on its inner surface to accommodate the bipod pin and rollers assembly.

3. The halfshaft assembly (100) as claimed in claim 2, wherein
- the bipod pin (16) is configured to have main body portion (16M) and leg portions (16a and 16b) formed on either sides of the main body portion (16M) through a stepped profile (16T);
- each of the legs (16a and 16b) of the bipod pin (16) is configured to have a groove (16G) at its distal end; and
- said groove (16G) houses a snap ring (22) such that it locks the roller (20) over the legs (16a and 16b) of the bipod pin (16).

4. The halfshaft assembly (100) as claimed in claim 3, wherein
- the roller (20) is configured to have a stepped profile (20T) at its inner top portion; and
- said stepped profile (20T) forms the base for the snap ring (22) to have positive locking of the roller (20) with the legs (16a and 16b) of the bipod pin (16).

5. The halfshaft assembly (100) as claimed in claim 4, wherein
- the shaft end (14a) of the bellow (14) is tightly fitted over the shaft (10) with the metal clip (26); and
- the flange end (14b) of the bellow (14) is tightly fitted over the muff cup / flange (12, 28) with metal clip (24).
6. The halfshaft assembly (100) as claimed in claim 5, wherein the snap ring (22) locks the roller (20) with the bipod pin (16) by having half sectional portion of the snap ring (22) within the groove (16G) of the legs (16a and 16b) of the bipod pin (16) and rest of the sectional portion of the snap ring (22) resting in the stepped profile (20T) of the roller (20) thereby imparting positive locking for the axial movement of the roller (20) over the bipod pin (16).

7. The halfshaft assembly (100) as claimed in claim 6, wherein
- end (10a) of the shaft (10) is fitted with a bipod pin (16), a pair of rollers (20) and a pair of snap rings (22) and said end (10a) is mounted inside a pair of oppositely profiled pockets (40) structured on the inner surface of the muff cup / flange (12); and
- the end (10b) of the shaft (10) is fitted with a bipod pin (16), a pair of rollers (20) and a pair of snap ring (22) and said end (10b) is mounted inside a pair of oppositely profiled pockets (40) str

8. The halfshaft assembly (100) as claimed in claim 7, wherein the muff cup / flange (12 and 28) is filled with the grease to facilitate lubrication to bipod pin and roller assembly.

Dated this 23rd day of Feb. 2023

Sahastrarashmi Pund
Head – IPR
Endurance Technologies Ltd.

To,
The Controller of Patents,
The Patent Office, at Mumbai