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
"RADIAL 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 an improved cage assembly for a needle roller bearing. More particularly, the present invention relates to an improved cage assembly with seamless joints, profile tabs and well-guided radial and axially spaced cage pockets and tabs for better needle retention in a bare cage.
DESCRIPTION OF THE PRIOR ART:
The cages roller bearing typically comprises a plurality of rolling elements and a cage capable of retaining such rolling elements. The cage has an outer peripheral surface, which retains the roller in a linear contact with the raceway surface. Due to such compact construction of the cage assembly along with the rolling element, it plays a vital role in facilitating high load bearing capacity and high rigidity and therefore, they are largely employed in various industries.
Several methods of manufacturing cages for roller bearings are known in the art. A typical cage construction method discloses bending steel sheets or steel pipe into a cylindrical shape and punching holes into it, which ultimately holds the rolling element. It is also known from the existing prior art that a long flat metal strip can be used for creation of ridges and pockets for rolling elements by profiling it with cold rolling process. The ridges are then flattened to form lateral projections extending into the pockets, which serves as retention mechanism for rolling elements. A predetermined length of the metal strip is wrapped into an annular shape to form the cage.
Another prior art discloses a method of making a cage assembly for use in a radial, axial or linear roller bearing. The method includes inter alia treating a metal strip by heat treatment or thermo chemical treatment to provide the metal strip with desired properties of hardness and punching a plurality of spaced slots into the metal strip for formation of pockets for receiving rolling elements.

Yet another prior art discloses a novel process for the production of sheet metal cages for cylindrical roller. The method includes inter alia shaping without cutting a sheet metal strip, shaping the central area of the sheet metal strip, punching out the central area to form the crossbars forming the pockets to accommodate rollers and being the sheet metal strip into a cylindrical shape and joining the abutting ends.
For the ease of understanding, a prior art method, commonly known in the industry is also disclosed hereinafter by way of an illustration:
Illustration:
Figure 1 discloses a bearing cage assembly (101) known in the art. The said bearing cage assembly (101) is made up of strip or frap type needle bearing cage. These bearings are typically made from low carbon strips. The construction of such bearing cage requires several layers of such strips compressed together to form an internal cavity (102) in the form of a pocket to retain the rolling element. Due to the varied thickness of low carbon strips, it becomes difficult to roll them into a cylindrical shaped assembly through cold rolling process. Further, with such combination of strips of varied thickness, it is cumbersome to carve projections to retain the rolling element.
The typical construction of cage assembly is such that the tabs and projections so made are sharp, blunt and have a skewed angle (103), due to which the lubrication does not stand leading to easy wear and tear. Also, due to a typical angular construction of projections and tabs, the retention of rolling elements become difficult and often lead to dislodging of rolling element from the cage assembly thereby causing damage to the end product, wherein such bearing assembly is used.

In light of the prior arts disclosed and the kind of construction of cage assembly so explained, there are several disadvantages associated with them, to name a few include:
i. lack of appropriate needle retention mechanism;
ii. lack of additional guidance to needle in cage pocket; iii. lack of suitably designed tabs for rolling elements; iv. lack of provision to sustain lubrication file between cage pocket and rolling elements etc.
Hence, it has always been a matter of great concern in the industry in relation to the problem failure of transmission, industrial equipments etc. due to bearing failure. This leads in abundant difficulty to find out and rearrange/repair dislodged needles and rollers into the cage pockets.
To overcome the disadvantages and shortcomings as 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 made up of seamless joint cage. The improved cage assembly comprises of internal and external tabs with concave radius profile protruding through outer and inner diameter. The cage assembly also has a well-guided structure between tabs and cage pocket to retain needles radially and axially.
OBJECT OF INVENTION:
The primary object of the present invention is to provide an efficient and compact bearing assembly consisting of a cage with specially designed 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 facility between the cage assembly and rolling elements.
Another object of the present invention is to provide a better design for cage assembly thereby reducing the consumption of material in terms of weight and mass.
SUMMARY OF THE INVENTION
An embodiment of the invention disclosing a needle roller bearing cage assembly having a base plate with seamless joints, said base plate having a plurality of pockets, each pocket has external and internal tabs alongside external and internal diameter to accommodate rolling elements.
An embodiment of the invention wherein the base plate is made up of either single or plurality of sheets coupled together or an open-ended cylindrical piece. The said base plate is made up of any metal or alloy.
In yet another embodiment of the invention, the pockets are punched through various operations such as pressing, cutting and the like depending upon the kind of base plate. The pockets on the base plate are equally spaced with each other. Further, the internal and external tabs have concave radius profile to match shape of rolling element.
In another embodiment of the invention, the protrusions of internal and external tabs are designed in such an angular fashion to provide maximum contact area of the rolling elements & to hold lubrication in space of roller and concave tabs.

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 shows a 3-D & cross-sectional view of an embodiment of a known prior art of a cage assembly.
FIG-2 shows a schematic view of an embodiment of the present invention disclosing a cage assembly.
FIG-3 shows a schematic view of an embodiment of the present invention disclosing a cage assembly.
FIG- 4 shows a cross-sectional view of the external tabs (A-A) and internal tabs (B-B) as marked in figure 2.
DETAILED DESCRIPTION OF THE INVENTION:
The present invention discloses a bearing cage assembly, which can be elaborated with reference to the following figures. However, the embodiments as discussed with reference to the figures should be construed as the limitation of the present invention. Further, several other embodiments, which may be created by slight variation in the existing mechanisms, which is obvious to a person skilled in the art may also be treated as part of the present invention.
Figure 1 discloses 3-D & cross-sectional view of the embodiment of a known prior art of a cage assembly and the same has been discussed in the prior art section of the specification.

Figure 2 discloses a schematic view of the embodiment of the present invention disclosing a cage assembly (100). The present invention discloses a cage assembly manufactured from a base plate having seamless joints. The said base plate can be made up of a metal or an alloy. In certain cases, instead of a base plate, a cylindrical open-ended pipe piece can also be used. Several manufacturing operations can be deployed to manufacture the cage assembly (100) depending upon the material used in manufacturing. The said base plate is treated through pressing and/or punching operations thereby creating several pockets, which can be equally spaced with each other, the kind of operation to create pockets may vary depending upon the type of base plate used to manufacture a cage assembly.
While manufacturing the cage assembly (100), the said base plate is rolled into a cylindrical shaped assembly having various pockets punched into it. The said pocket walls are further subjected to creation of internal and external tabs (105 & 110). The said internal and external tabs are used to retain the rolling elements (115). The said rolling elements can be various kinds of rollers depending upon the kind of bearing.
Figure 3 shows a schematic view of an embodiment of the present invention disclosing a cage assembly (125). On the pocket walls of the cage assembly as discussed, there exist internal and external tabs used for retaining rolling elements. The external tabs (120) are created on both the ends of the pocket wall whereas the internal tab (130) is created on the middle of the length of the rolling element. The construction of external tabs (120) and internal tabs (130) are angularly protruded in such a way that there is a significant increase in the contact area of the rolling elements which in turn helps in increasing the rigidity and retention capacity of the cage assembly (125). The two external tabs (120) can support the ends of the rolling elements thereby preventing them from falling off from the cage assembly (125) from outside diameter of the cage and helps in creating lubrication film on outside diameter of rolling elements. The

internal tab (130) can support the middle portion of the rolling elements thereby preventing it from falling inside the cage bore and helps creating a lubrication film to prevent the rolling elements from wear and tear.
The internal (130) and external (120) tabs are specially designed with a concave shape thereby protecting the rolling element from wear and tear caused due to friction between the rolling elements and tabs. The design of cage assembly (125) is such that the rolling elements are well guided radially and axially through unique spacing between the cagepockets and tabs.
Figure 4 show a cross-sectional view of the external tabs (A-A) and internal tabs (B-B) as marked in figure 2. The external tabs as shown in Section A-A are in concave shape and having specific angular protrusion within which the rolling element rotates. Similarly, the internal tabs as shown in Section B-B also have specific angular protrusion within which the rolling element rotates. The protrusion of the external and internal tabs is such that it not only effectively retains the rolling elements internally and externally in the cage assembly but also protects it from wear and tear by creating lubricating film over all.
The embodiments of the invention described, referred hereinabove are calculated 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. a base plate having seamless joints;
ii. creating a cage assembly by punching plurality of pockets in the said
base plate; iii. said pocket walls have external and internal tabs alongside external and
internal diameter to accommodate rolling elements; iv. said external tabs protrude outside the external diameter at both the
ends of the pocket walls.
2. A needle roller bearing cage assembly as claimed in claim 1, wherein the base plate is made up of either single or plurality of sheets coupled together or an open-ended cylindrical piece.
3. A needle roller bearing cage assembly as claimed in claim 2, wherein the sheet of said base plate is made up of any metal or alloy.
4. A needle roller bearing cage assembly as claimed in claim 1, wherein the said pockets in the base plate are punched through various operations such as pressing, cutting and the like depending upon the kind of base plate.
5. A needle roller bearing cage assembly as claimed in claim 4, wherein said pockets are equally spaced with each other.
6. A needle roller bearing cage assembly as claimed in claim 1, wherein the internal and external tabs have concave radius profile to match shape of rolling element.

7. A needle roller bearing cage assembly as claimed in claim 1, wherein the protrusions of internal and external tabs are designed in such an angular fashion to provide maximum contact area of the rolling elements & to hold lubrication in space of roller and concave tabs.
8. A needle roller bearing case assembly as claimed in claim 1, wherein said rolling elements are rollers or needles depending upon the kind of bearing.