FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
AND
THE PATENTS RULES, 2003 COMPLETE SPECIFICATION
(See section 10; rule 13)
1. TITLE OF THE INVENTION
"THRUST ROLLER AND NEEDLE BEARING WITH CAGE ASSEMBLY FOR NEEDLE RETENTION"
2. APPLICANT:
(a) Name : NRB Bearings Ltd.
(b) Nationality : Indian
(c) Address : Pokhran Road-2,Majiwade
Thane (West) 400 610
3. PREAMBLE TO THE DESCRIPTION:
The following specification particularly describes the invention and the manner in which it is to be performed.

FIELD OF THE INVENTION:
The present invention relates to a thrust roller in a needle bearing cage assembly.
BACKGROUND OF THE INVENTION:
A thrust needle roller bearing comprises needle rollers and a cage assembly, in which the rolling element can be accommodated. Due to its typical construction, the bearing advantageously attains high load carrying capacity and high rigidity, for its small projection area. The thrust needle roller bearing finds its use in almost all type of transmission i.e. manual, automatic, continuous and/or variable.
Several prior arts are known, which discloses the typical construction of thrust needle roller bearing. For the ease of understanding, a prior art method, commonly known in the industry is also disclosed hereinafter by way of an illustration:
Illustration of prior art:
Figures 1, 2, 3, 4 and 5 are an example of a thrust bearing in a needle roller thrust bearing assembly. The existing prior art typically discloses construction mechanism of bearing assembly, which includes cage construction formed from from a single piece of metal into a desired shape, which along with specially designed openings, retains and guides the rolling elements. In cross-section, such cages bear the shape similar to that of the Greek symbol sigma. The sigma formatting on the cage assembly helps in generating internal cavity to hold needles and rollers.

Figure 1 exhibits an existing prior art of a cage assembly (100) with rolling elements. The cage assembly includes rolling elements (110) positioned between series of flanges (120). Typically, these flanges (120) have a box type folding, which is similar to that of the Greek symbol sigma. The rolling elements are equally spaced between these flanges, which facilitates its rotation.
Figure 2 displays a single piece integer of a cage (200), which is typically made from press route. The cage (200) particularly illustrates series of square shaped flanges (210), which have hollow pockets (220) in between to retain rolling elements.
Figures 3, 4 and 5 demonstrate a single cage slot (300) positioned between square-shaped flanges (310) with a rolling element (320). The square shaped flanges (310) are designed in such a fashion that it contains a vacant slot (330) alongside the external wall of the flanges (310). The slot (330) acts as a retainer to the rolling element and prevents the rolling element from falling off the bearing cage assembly. Due to the typical construction design of the flanges, the bearing cage does not have any provision to retain lubrication between the rolling element and the flange-wall. Further due to the square-shape construction of the flange, the wear and tear of the rolling element is significant.
In light of above, the construction of the bearing cage as disclosed in the prior arts lack several mechanisms such as: i. lack of needle retention mechanism; ii. lack of needle guidance mechanism; iii. lack of lubrication between cage and lolling element etc.
Due to the aforesaid drawbacks, the cage designs typically result in premature failure, noise generation, lubrication and the like. To overcome the drawbacks discussed herein above and several others associated with the faulty design of the cage assembly, the present invention meets the desired requirements, which

discloses an improved cage assembly with a thrust roller having needle cage retainer made from strip having two parts.
OBJECT OF THE INVENTION
The primary object of the present invention is to provide efficient and compact bearing assembly consisting of a cage with special tabs for holding rolling elements i.e. needle or rollers and improved cage life.
Another object of the present invention is to provide an effective cage manufacturing method as compared to a strip form or a frap type design.
Yet another object of the present invention is to provide an effective lubrication mechanism between the cage assembly and rolling elements.
Addition objective is to hold rolling element effective in cage and to avoid dislodge of rolling element from cage pocket.
SUMMARY OF THE INVENTION
The present invention discloses a needle roller bearing cage assembly comprising at least-two cage halves aligned together through specifically designed key slots located at each end of a cage half. Each cage half has plurality of pockets punched to facilitate retention of rolling elements, wherein said pockets are equally spaced with each other. The cage halves have internal and external tabs projecting on the outer diameter over the face profile of the said cage halves such that projection of tabs on the outer diameter of cage halves forms a concave shaped profile for retention of rolling elements. Each cage half is interlocked thereby forming single piece sigma integer on inner bore and outer diameter of cage halves.

In an embodiment of the needle roller bearing cage assembly, the cage halves are manufactured using strips made up of any metal or alloy. Further, the key slots in the cage assembly are designed on each end of a cage half to facilitate better alignment of cage halves at the time of interlocking.
In another embodiment of the needle roller bearing cage assembly, the protrusion of internal and external tabs on the face profile of cage half are such that it forms a convex shaped profile to enhance lubrication and reduce internal friction. Further, the projection of tabs is such that the length and breadth of the projected tab is less than the diameter of rolling element thereby forming a concave shape for better retention of rolling elements.
In yet another embodiment, the top and bottom halves of the cage assembly can be locked together by interlocking outside edge of bottom half over top half. Further, the said locking can be done by folding outside edge of bottom half over the top half the single piece sigma integer locking.
BRIEF DESCRIPTION OF THE DRAWINGS:
The present invention overcomes the aforesaid drawbacks and the above and other objects, features and advantages of the present invention will now be described in greater detail with reference to the accompanying drawings in which:
FIG-1 depicts a cross-sectional view of sigma, the embodiment of the prior art.
FIG-2 depicts a cross-sectional view of single piece integer of a cage of the prior art.

FIG-3 depicts a cross-sectional view of a single cage slot with needle of the prior art.
FIG-4 depicts a cross section of a single cage slot along with line A-A (as shown in FIG-3)
FIG-5 depicts a cross section of a single cage slot along with line B-B (as shown in FIG-3).
FIG-6 depicts a cage assembly with rolling elements in the present invention.
FIG-7 illustrates a cross-sectional view of the needle cage along with needle and lubrication retention mechanism along with line C-C (as shown in Figure 6).
FIG-8 illustrates a needle cage bearing along with locking provision and cage orientation from top and bottom.
FIG-9 illustrates a cross-sectional view of cage locking mechanism of needle cage bearing.
FIG-10 illustrates a cross-sectional view of the needle cage assembly along with the cage projections and alignment slots along with line E-E (as shown in Figure 6).
DETAILED DESCRIPTION OF THE INVENTION:
Figures 1 to 5 illustrate the construction of needle cage assembly and the shortcomings associated with it, as discussed in the description of prior art section above.

With reference to Figures 6, 7, 8, 9 and 10, the needle cage assembly and its construction is discussed herein below.
As depicted herein, Figure 6, a cage assembly (500) can be divided into two cages halves (510) and (520). The cage halves (510) and (520) can be manufactured by a strip through pressing operation. The cage halves (510) and (520) have specially designed tabs (530) to hold the rolling elements (540). The tabs (530) can be designed to have concave shape to facilitate retention of rolling element (540). In an embodiment of the present invention, the length and breadth of the tab (530) can be less than that of the rolling element (540) molded in a concave shape, whereby due to its unique design, a lubrication film is generated around the rolling element thereby preventing it from wear and tear.
Figure 7 illustrates a cross-sectional view of a needle cage (600) along with rolling element and lubrication retention mechanism along with line C-C (as shown in Figure 6). The needle cage (600) depicts concave shaped tabs (610, 620, 630 and 640) to roller/needle outside diameter with a rolling element positioned within it. The arrangement between the rolling element and the tabs (610,620, 630 and 640) is such that it has sufficient needle retention ability (650, 660) and facilitates lubrication (670).
Figure 8 illustrates a needle cage bearing assembly along with locking provision and cage orientation of top and bottom halves. An embodiment of the present invention discloses a needle cage bearing assembly (700) possessing a cage alignment mechanism (710, 720 and 730) wherein the top and bottom halves of the bearing cage can be aligned.
Figure 9 illustrates a cross-sectional view of cage locking mechanism of needle cage bearing. An embodiment of the present invention as discussed provides for a locking mechanism with the outer diameter (810) and inner diameter (820).

Figure 10 illustrates a cross-sectional view of the needle cage assembly along with the cage projections and alignment slots along with section E-E (as shown in Figure 8). In an embodiment of the present invention, a cage assembly (900) depicts the projections (910) of top cage held and located at the cut-out of bottom half. The arrangement as discussed herein ensures proper orientation and alignment of opening of slots.
The embodiments of the invention described, referred hereinabove are provided to overcome the hurdles and achieve benefits, and advantages as hereinabove set forth. It may be possible to further modify and improve the described invention within the scope of the unity of the present invention.

CLAIMS:
We claim:
1. A needle roller bearing cage assembly comprising:
i. atleast two cage halves aligned together through specifically
designed key slots located at each end of a cage half; ii. each cage half has plurality of pockets punched to facilitate
retention of rolling elements; iii. said pockets are equally spaced with each other; iv. said cage halves have internal and external tabs projecting on the
outer diameter over the face profile of the said cage halves; v. projection of tabs on the outer diameter of cage halves forms a
concave shaped profile for retention of rolling elements; vi. said cage halves are interlocked thereby forming single piece
sigma integer on inner bore and outer diameter of cage halves.
2. A needle roller bearing cage assembly as claimed in claim 1, wherein said cage halves are manufactured using strips made up of any metal or alloy.
3. A needle roller bearing cage assembly as claimed in claim 1, wherein the key slots are designed on each end of a cage half to facilitate better alignment of cage halves at the time of interlocking.
4. A needle roller bearing cage assembly as claimed in claim 1, wherein the protrusion of internal and external tabs on the face profile of cage half is such that it forms a convex shaped profile to enhance lubrication and reduce internal friction.

5. A needle roller bearing cage assembly as claimed in claim 1, wherein the projection of tabs is such that the length and breadth of the projected tab is less than the diameter of rolling element thereby forming a concave shape for better retention of rolling elements.
6. A needle roller bearing cage assembly as claimed in claim 1, wherein the top and bottom cage halves are locked together by folding outside edge of bottom half over the top half the single piece sigma integer locking.