GB1562660A - Cage for a spherical roller bearing - Google Patents

Description

(54) CAGE FOR A SPHERICAL ROLLER BEARING (71) We, NTN TOYO BEARING COMPANY LIMITED, a Company organised and existing under the laws of Japan, of No. 25, 1-Chome, Kyommachibori, Nishi-ku, Osaka-shi, Osaka-fu, Japan, do hereby declare the invention, for which we pray that a Patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: The present invention relates to a cage for a spherical roller bearing.

Comb-shaped roller cages are hitherto known for use with spherical roller bearings.

The roller cage includes an annular central portion having a plurality of fingers which project axially from the opposite sides thereof and are adapted to define roller pockets between the circumerentially ad Joining fingers so that the rollers are received in the respective pockets. The roller pockets are formed by boring, which term embraces the rotary cutting operations of drilling and milling and broaching, in axial direction of the pockets, utilizing cutter tools, the profile and size of which corresponds to that of the roller.

Considering the roller retaining conditions in the assembly of the spherical roller bearing generally with respect to the circumferential as well as axial shift and the skewing of the rollers, the roller cage of the type as above-mentioned has certain drawbacks. The spherical rollers received in the pockets are prevented from shifting circumferentially, not from shifting axially and skewing. Therefore, during operation, the rollers are liable to depart from the proper path owing to the external forces, dimensional factors in the assembly or the like.

Such roller movement departing, induces abnormal loads and thus increased wear will be caused, since the cage itself is unstable and unable to bring the rollers into correct position. Further, if the cage of this type is manufactured according to a method employed heretofore, accuracy in dimension would deviate as a result of the abrasion of the tool, variation in the surface roughness, and the deformation of the fingers, etc.

Another type of the roller cage, wherein each roller pocket comprises an opening confined by four faces, is also known. The cage of this type is capable of preventing the rollers from circumferentially and axially shifting as well as skewing. In the formation thereof, it is, however, quite difficult to attain a high degree of accuracy, and that with special jigs and a method. In addition, there remain difficulties in technique such as, for instance, that the deformation of partitions between the pockets is a necessity because of the fact that the partitions should be caulked prior to the assembling of the cage together with the rollers onto the inner race ring, in order that the rollers may be prevented from falling off.

The primary object of the invention is to provide an improved roller cage possessing a desirable structure eliminating disadvantages with the structures of the conventional roller cages.

Accordingly the present invention is a cage for a spherical roller bearing bored from an annular blank, characterised in that a plurality of roller pockets is bored symetrically in a double-row at distributions uniformly about the periphery of an annular cage body the thickness of which is symetrically reduced towards its axially outer rim each of pockets for rollers comprising an opening being defined by four walls, and extending in oblique direction toward the bearing centre completely through the cage body, and that partitions between the pockets are provided at longitudinally central locations of the opposite walls thereof with circumferentially projecting nibs, each pair of said nibs being opposed to and spaced from each other across the pocket by a distance slightly less than the largest diameter of the roller, each of said opposite walls being provided with a concavity extending in the direction of the pocket walls.

The opposing walls of the adjacent partitions are adapted to correspond to the spherical profile of the roller so that the rollers are retained under the correct guidance, the rollers engage the walls with respect line contact without the occurance of abnormal forces between the rollers and the walls, this will ensure the well balancedrunning of the bearing and an elongation of the cage life, unlike the comb-shaped type in which the rollers engage the fingers only at a point or along a short line, resulting in abnormal bearing stresses.

For the purpose of preventing the rollers received in the pockets from falling off, the partitions are provided at radially outermost and longitudinally central locations of the opposite walls thereof with circumferentially projecting nibs. A pair of nibs is opposed to an spaced from each other across the pocket by the distance slightly less than the largest diameter of the roller. The passage of the roller between the opposing nibs is allowed by virtue of the temporary resilient deformation of the nibs, and the repeated operation of inserting and removing the rollers, for any purposes, is enabled.

As the concavities for storing the lubricant adhered onto the roller surface are formed in the opposite walls of the respective partitions, lubricating effects about the rollers improve remarkably.

Further features of the invention will be apparent from the following description taken in connection with accompanying drawings in which; Figure 1 is a cross-sectional view illustrating in part a completed spherical roller bearing with the cage in accordance with the invention; Figure 2 is a fragmentary sectional view taken on line 11-11 in Figure 1; Figure 3 is a fragmentary plan view taken on line 111-111 in Figure 1; Figure 4 is a fragmentary perspective view illustrating how the cage body is formed from an annular blank; Figures 5a and 5b illustrate how the pilot bores for the pocket openings are formed in the cage body; Figures 6a and 6b illustrate how the pocket openings are machined to the finished shape; and Figures 7a and 7b illustrate how the nibs and the concavities are formed in the walls of the partitions between the pockets.

Referring to Figure 1, designated by the numeral 1, 1 are spherical or barrel-shaped rollers; 2 an outer race ring having an inner race surface corresponding to the spherical profile of the rollers 1; 3 an inner race ring having an outer race surface corresponding to the spherical profile of the rollers 1; and 4 a cage in accordance with the present invention. A plurality of the rollers 1, 1 is arranged in double-row symetrically on the opposite sides of the center line A0 of symetry which perpendicularly intersects the body axis at the bearing center 0.

The cage 4 comprises an annular cage body 5 symetrically reduced in outer diameter toward the axial ends, with the annular radially inwardly projecting guide rim 6 left at an axially central location of the inner periphery.

A plurality of pockets 7 for the rollers 1, is formed at the locations distributed uniformly about the periphery of the cage body 5.

Each of the pockets 7 is such an opening as confined by four faces and extending in an oblique direction at the angle ss toward the bearing center 0 completely through the cage body 5. The circumferentially opposing two of the four faces are formed in the opposing walls of partitions 8, 8 adjoining across the pocket opening 7 and are adapted to corresponding to the spherical profile of the roller in order that the shape of the pocket opening may conform substantially to that of the axial section of the roller, and that the roller may be received in the pocket with the sufficient clearance required for the proper rotation of the roller.

For the purpose of preventing the rollers 1 from falling off the pockets 7, circumferentially projecting nibs 9 are provided at radially outermost and longitudinally central locations of the opposite walls of the respective partitions 8. A pair of said nibs 9, 9 is opposed to and spaced from each other across the pocket 7 by the distance H slightly less than the largest diameter of the roller 1. In inserting the roller 1 into the pocket opening 7 for assembly, the pair of nibs 9, 9 is forced to open as the roller 1 is snapped-in, and then the resilent deformation thereof occurs to allow the passage of the roller 1 therebetween, but the initial state will be recovered after the passage.

This temporary resilent deformation of the nibs 9, 9 will enable the repeated operation of inserting and removing the roller as required for any purposes.

A shallow concavity 10 extending in the axial direction of the pocket opening 7 is formed in each wall beneath the nib 9 to store the lubricant adhered onto the roller surface, thereby improving the lubricating effects about the rollers remarkably.

A method of manufacturing the cage the structure of which is hereinbefore described will be apparent from the following description in order of successive steps.

In a pre-machining step, the cage body 5 symetrically reduced in outer diamter toward the axial ends is formed from an annular blank 5' by turning the outer and inner peripheries of the blank, while leaving an annular radially inwardly projecting guide rim 6 at an axially central location of the inner periphery. (Figure 4) The formation of the plurality of pockets 7 is carried out as follows: Referring to Figure 5a, firstly pilot bores 7' which are slightly smaller than the pocket opening 7 of the finished shape are bored at the respective pocket locations in the cage body 5. This boring operation is carried out by shifting a milling cutter 11 in such a way as shown in Figure 5b.

Then the pilot bores 7' are machined to the finished shape of the pocket 7 by utilizing a broach 12, the shape of which corresponds in cross-section to the finished shape of the pocket 7. It is, however, to be understood that ridges 9',9' extending parallel to the pocket axis are left at longitudinally central locations of the opposing walls of the adjacent partitions 8, 8 as shown in Figure 6a, since the broach 12 is provided at the opposite sides thereof with longitudinal recesses 13, 13 as shown in Figure 6b.

Finally, the lower portions of the ridges 9', 9' and further the walls of the partitions 8, 8 are recessed to a suitable extent in such a manner than an another milling cutter 15 is inserted into the pocket opening 7 from the outside and shifted laterally to its axis of rotation to form the shallow concavities 10, 10 which extend in the axial direction of the pocket opening 7 and lie in the relatively wide area terminated beneath the nib 9, simultaneously leaving the nibs 9, 9 at the outermost locations of the ridges 9', 9' as shown in Figures 7a and 7b.

During the pocket forming operation, the axes of the milling cutter 11. 15 and the broach 12 should be maintained parallel to the pertinent pocket axis BO so that the each pocket 7 may be formed in the precisely oblique relationship to the center line A0 of symetry at the angle ss.

Although in the above description the formation of the pockets is carried out by the milling and the broaching, various ways may be adoptable so far as the pockets of the predetermined shape are obtained. with the ridges left on the opposing walls of the adjacent partitions for the later formation of the nibs WHAT WE CLAIM IS: 1. A cage for a spherical roller bearing bored from an annular blank characterised in that a plurality of roller pockets is bored symetrically in double-row at locations distributed uniformly about the periphery of an annular cage body the thickness of which is symetrically reduced towards its axially outer rims, each of said pockets comprising an opening defined by four walls and extending in oblique direction toward the bearing centre completely through the cage body, and that partitions between the pockets are provided at longitudinally central locations of the opposite walls thereof with circumferentially projecting nibs, each pair of said nibs being opposed to and spaced from each other across the pocket by a distance slightly less than the largest diameter of the roller, each of said opposite walls being provided with a concavity extending in the direction of the pocket axis.

2. A cage for a spherical roller bearing as set forth in Claim 1, wherein the nibs are formed at radially outermost locations.

3. A cage for a spherical roller bearing as set forth in Claims 1 or 2 wherein the concavity is located beneath the nib.

4. A cage for a spherical roller bearing as set forth in Claims 1, 2 or 3, wherein the shape of each pocket opening conforms substantially to that of the axial section of the roller.

5. A cage as claimed in Claim 1, substantially as hereinbefore described with reference to the accompanying drawings.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (5)

1. **WARNING** start of CLMS field may overlap end of DESC **.

   annular blank 5' by turning the outer and inner peripheries of the blank, while leaving an annular radially inwardly projecting guide rim 6 at an axially central location of the inner periphery. (Figure 4) The formation of the plurality of pockets 7 is carried out as follows: Referring to Figure 5a, firstly pilot bores 7' which are slightly smaller than the pocket opening 7 of the finished shape are bored at the respective pocket locations in the cage body 5. This boring operation is carried out by shifting a milling cutter 11 in such a way as shown in Figure 5b.

   Then the pilot bores 7' are machined to the finished shape of the pocket 7 by utilizing a broach 12, the shape of which corresponds in cross-section to the finished shape of the pocket 7. It is, however, to be understood that ridges 9',9' extending parallel to the pocket axis are left at longitudinally central locations of the opposing walls of the adjacent partitions 8, 8 as shown in Figure 6a, since the broach 12 is provided at the opposite sides thereof with longitudinal recesses 13, 13 as shown in Figure 6b.

   Finally, the lower portions of the ridges 9', 9' and further the walls of the partitions 8, 8 are recessed to a suitable extent in such a manner than an another milling cutter 15 is inserted into the pocket opening 7 from the outside and shifted laterally to its axis of rotation to form the shallow concavities 10, 10 which extend in the axial direction of the pocket opening 7 and lie in the relatively wide area terminated beneath the nib 9, simultaneously leaving the nibs 9, 9 at the outermost locations of the ridges 9', 9' as shown in Figures 7a and 7b.

   During the pocket forming operation, the axes of the milling cutter 11. 15 and the broach 12 should be maintained parallel to the pertinent pocket axis BO so that the each pocket 7 may be formed in the precisely oblique relationship to the center line A0 of symetry at the angle ss.

   Although in the above description the formation of the pockets is carried out by the milling and the broaching, various ways may be adoptable so far as the pockets of the predetermined shape are obtained. with the ridges left on the opposing walls of the adjacent partitions for the later formation of the nibs WHAT WE CLAIM IS: 1. A cage for a spherical roller bearing bored from an annular blank characterised in that a plurality of roller pockets is bored symetrically in double-row at locations distributed uniformly about the periphery of an annular cage body the thickness of which is symetrically reduced towards its axially outer rims, each of said pockets comprising an opening defined by four walls and extending in oblique direction toward the bearing centre completely through the cage body, and that partitions between the pockets are provided at longitudinally central locations of the opposite walls thereof with circumferentially projecting nibs, each pair of said nibs being opposed to and spaced from each other across the pocket by a distance slightly less than the largest diameter of the roller, each of said opposite walls being provided with a concavity extending in the direction of the pocket axis.
2. 2. A cage for a spherical roller bearing as set forth in Claim 1, wherein the nibs are formed at radially outermost locations.
3. 3. A cage for a spherical roller bearing as set forth in Claims 1 or 2 wherein the concavity is located beneath the nib.
4. 4. A cage for a spherical roller bearing as set forth in Claims 1, 2 or 3, wherein the shape of each pocket opening conforms substantially to that of the axial section of the roller.
5. 5. A cage as claimed in Claim 1, substantially as hereinbefore described with reference to the accompanying drawings.