Roller bearing cage

A cage for the rollers in a roller bearing in which the roller axes (2) define an angle with the bearing axis (3) has two annular portions (4, 5) and intermediate cage bars (6) defining cage pockets (7). The bars are situated radially inside of the roller axes with respect to the bearing and a flange (8) for guiding the roller by contacting their ends is extending radially outwards from one of the annular portions (4). A protrusion (9) is arranged on the flange (8) in connection to each pocket (7) or insertion into a recess in the adjacent roller end and thereby keeping the roller in the cage pocket. A recess (10) in the other annular portion (5) opposite each protrusion (9) simplifies the snapping of the roller into its pocket in the cage.

The invention relates to a roller bearing cage of the kind defined in the 
introductory clause of claim 1. 
A roller cage of pressed sheet metal having stamped roller pockets for use 
in spherical roller bearings is known by e.g. U.S. Pat. No. 2,218,985. 
Roller guidance and cage centering take place in such a cage by the 
rollers contacting the cut rims of the roller pockets. This contact is 
unsuitable, since the contact surfaces are comparatively small, which 
gives a high contact pressure and poor lubrication conditions and may 
cause excessive wear. 
U.S. Pat. No. 2,375,145 shows that roller guidance can be effected by a 
cage having a flange with a portion contacting an end surface of a roller 
mounted in the cage. The general structure of such a cage entails certain 
disadvantages, however. The radially inwardly directed flange occupies the 
limited space between two adjacent rows of rollers, which requires a wider 
bearing or shorter rollers than necessary. The cage pockets are open at 
one side, which means, despite the fact that there is a guiding flange, 
that the roller guidance is inferior to the roller guidance in a bearing 
having a cage with closed roller pockets. The cage and the rollers must be 
mounted on the inner ring of the bearing by pressing the rollers radially 
into the respective pockets because the inner ring is provided with 
flanges. The axial protrusions of the cage are pressed apart by the 
contact with the envelope surfaces of the rollers during mounting. These 
surfaces are sensitive to defects, since they take up the load in the 
bearing and roll against raceways in the outer and the inner rings. The 
surfaces can easily be damaged during mounting by the contact with the 
protrusions, which are comparatively hard and rigid. 
The object of the present invention is to provide a cage which gives a good 
roller guidance, requires a small space in the axial direction of the 
bearing and permits careful and safe mounting of the rollers in the cage. 
This is obtained in a cage of the kind mentioned above by giving it the 
characterizing features stated in claim 1. 
Such a cage can be produced by pressing and stamping of sheet metal blanks, 
and a bearing comprising such a cage can be quickly and easily assembled. 
The cage can be centered in the bearing by its contact with the rollers 
and does not have to be equipped with parts which contact a bearing ring.

The cage here described is suitable for use in a double row spherical 
roller bearing. In the section of FIG. 1, a roller 1 for such a bearing is 
outlined and placed in its proper position in the cage. The axis 2 of the 
roller forms an angle with the central axis 3 of the cage, whereby the 
axes or the rollers mounted in the cage define a cone with its apex on the 
axis 3, which coincides with the axis of the bearing. The cage comprises 
two closed annular portions 4, 5 and a number of bars 6 which extend 
between the portions 4, 5 and define roller pockets 7. The bars 6 extend 
mainly parallel to the axes 2 of adjacent rollers and are situated between 
the axis 3 of the cage and the axes 2 of the rollers. Thereby the bars 
occupy a minimum of space between the rollers, and the contact against the 
envelope surfaces of the rollers has a great radial force component with 
respect to the cage, so that the cage is firmly centered in the bearing by 
its contact with the rollers. 
A flange 8 is arranged at one end of the cage in connection to one of the 
annular portions 4 and extend outwardly from the center of the cage. 
Thereby it does not significantly limit the space between the rows of 
rollers in a double row spherical roller bearing. The side surface of the 
flange which is facing the pockets 7 contacts the rollers mounted in the 
cage on their end surfaces facing the flange. The flange suitably extends 
as far radially outwards that the extension of the roller axis 2 
intersects the flange surface which contacts the rollers, whereby maximum 
roller guiding ability is achieved. 
Since the cage bars 6 are situated radially inside the roller axes 2 with 
respect to the cage axis 3 and thereby do not limit the radially outward 
mobility of the rollers, the cage is provided with an arrangement for 
keeping the rollers in the cage also when they are not enclosed in an 
outer ring. This arrangement comprises protrusions 9 provided on the 
flange 8 and extending towards the roller pockets and having a surface 
which, in the direction towards the bearing axis, successively increases 
its distance from the flange surface. Each protrusion is situated so as to 
face the middle of each pocket. The protrusion is intended for insertion 
in a recess in the end surface of a roller situated in the opposing 
pocket, whereby the wedge shape of the protrusion allows the roller to be 
snapped into position in the pocket by pressing the end surface of the 
roller radially inwards past the protrusion 9. 
This procedure is possible because of the resiliency of the cage. In order 
to ensure that the roller takes the correct position in relation to the 
pocket and the protrusion 9 during the snap action, recesses 10 are 
provided at the opposite side of the cage in relation to the flange 8 in 
the annular portion 5. The recesses oppose the protrusions 9. Therewith 
the end portion of each roller can be directed correctly with respect to 
the protrusion 9 by being placed in the recess. The existence of the 
recess also allows the roller to be axially displaced from the protrusion 
9 in the initial stage of the snapping procedure, which simplifies 
mounting. The envelope surfaces of the rollers are not subjected to any 
pressure during the mounting procedure, which diminishes the risk for 
roller damages. A convex edge 11 is suitably provided on either side of 
each recess 10, which edge extends towards the interior of the pocket. 
This arrangement prevents the edges of the roller from contacting the cage 
when the rollers are tilted, thereby diminishing wear in the bearing. 
Also the flange 8 has suitably a convex surface facing the rollers. The 
surface has the shape of a torus in order to give a suitable contact 
against the adjacent roller ends. A flange 12 is preferably arranged also 
in connection to the annular portion 5. Such a flange gives the cage an 
increased stability and strength. If the flange extends inwardly, the 
whole cage may be formed in a simple manner in a pressing and punching 
tool. 
The cage in a double row spherical roller bearing is preferably 
supplemented with a loose guide ring 13 (FIG. 1) which encloses the flange 
8 of the cages of both rows of rollers. FIG. 1 shows the cage of one row 
of rollers only. The guide ring co-operates with the cages in guiding the 
rollers. 
If a roller in the loaded zone in the bearing has a tendency to skew it 
will be guided by the contact with the guide ring. At the same time, the 
guide ring will be displaced toward the loaded zone of the bearing by 
being squeezed into a wedge shaped space between the ends of the rollers 
of both rows of rollers. Therewith the guide ring displaces the cage 
radially towards the loaded zone of the bearing due to its contact with 
the cage in the unloaded zone so that the play of the rollers in the cage 
pockets in the loaded zone decreases, whereby the guidance of the rollers 
is further improved. 
In high speed bearings, where roller guidance is particularly difficult, 
the centrifugal force acting on the unloaded rollers will press the 
rollers of the respective rows towards each other, thereby displacing the 
guide ring in the direction of the unloaded zone, whereby the axial play 
between the roller ends and the guide ring in the loaded zone decreases. 
This improves the roller guidance both in the loaded and in the unloaded 
zone, which is important in high speeds. 
The position of the guide ring on the cage thus makes the guide ring 
cooperate with the cage in a manner which decreases the possibility of the 
roller to skew during operation.