Cage for rolling bearings and related rolling bearing unit
A rolling bearing unit ( 6 ) includes a rolling bearing ( 3 ) and an annular cage ( 1 ) formed by two half-cages ( 10 ) connected together by pins ( 16 ) and holes ( 18 ) formed alternately in a row on each half-cage ( 10 ). The pins ( 16 ) of a half-cage being snap-coupling with the holes ( 18 ) of the opposing half-cage. Rigid blocks ( 21 ) alternate with recesses ( 22 ). The rigid blocks ( 21 ) of a half-cage ( 10 ) coupling with the recesses ( 22 ) of the opposing half-cage ( 10 ). The projecting rigid blocks ( 21 ) bearing the projecting pins ( 16 ). The holes ( 18 ) being formed at the back of the recesses ( 22 ), so that the half-cages ( 10 ) are connected by a first coupling and a second coupling in series ( 14, 15 ), designed to separately absorb tangential and axial stresses. The half-cages ( 10 ) are provided with a radial annular ridge ( 34 ) acting as a screen.
1 . An annular cage for retaining rolling bodies in a rolling bearing, configured to be in use mounted interposed between respective inner and outer rings of the rolling bearing and comprising a plurality of radially passing-through seats or pockets arranged in a row with respect to one another and each configured to accommodate a respective rolling body, said plurality of radially passing-through seats or pockets being bounded, each, by a respective spherical surface having a center lying in a radial median plane of the cage coincident in use with a corresponding radial median plane of the rolling bearing, the annular cage comprising:
two axially opposite and essentially symmetrical half-cages in relation to the median plane, connected with each other, each half-cage presenting an annular body and a plurality of at least partially hemispherical cavities facing axially the hemispherical cavities of the opposite half-cage, to define with the latter said seats or pockets; and
connection elements to constrain together the two opposing half-cages to form jointly said annular cage, the connection elements include, in combination:
first pairs of conjugate connection elements consisting, for each first pair, of a pin at least partially elastically deformable and a respective hole configured to snappingly receive the pin, each half-cage being provided with a plurality of said pins projecting axially from the annular body on the side of a first frontal face of the annular body and of a corresponding plurality of holes obtained axially in the annular body on the side of a second frontal face thereof, opposite to the first frontal face, the annular body of each half-cage being provided with said holes and said pins that are so arranged that each pin of said half-cage mates with the hole facing said pin of the opposite half-cage through an opening of the hole facing the first frontal face; and
second pairs of conjugate connection elements consisting, for each second pair, of a male element configured as a substantially rigid, solid block projecting axially from the first frontal face of the annular body of each half-cage, and of a corresponding recess configured to mate in integral manner with the solid block constituting the male element, the recess being obtained through the first frontal face of the annular body of each half-cage; each half-cage being provided with a plurality of said male elements and of a corresponding plurality of said recesses arranged so that each male element of a half-cage mates with a recess facing said male element of the opposite half-cage;
each pin projecting axially from a corresponding male element consisting of one said solid block, so as to be arranged axially in series with said solid block, downstream of said solid block with respect to said first frontal face of the annular body of each half-cage; and each recess being arranged axially in series with a respective said hole, upstream of said hole with respect to said first frontal face of the annular body of each half-cage.
2 . The annular cage according to claim 1 , wherein the conjugate connection elements of said second pair of connection elements are configured to receive tangential components of mechanical stresses acting in use on the annular cage, while the conjugate connection elements of said first pair of connection elements are configured to receive axial components of said mechanical stresses.
3 . The annular cage according to claim 2 , wherein each said solid block constituting one said male element of said second pairs of conjugate connection elements presents a truncated-pyramidal shape, as well as each corresponding said recess, so that the coupling between each solid block and the corresponding recess is by means of surfaces arranged obliquely to a common axis of symmetry of the opposite half-cages.
4 . The annular cage according to claim 3 , wherein each said solid block constituting one said male element of said second pairs of conjugated connection elements is laterally provided, in a circumferential direction, with respective radial reliefs or teeth configured to snap-couple with respective radial grooves obtained within each said recess; or, conversely, the radial grooves being machined laterally on said solid blocks constituting said male elements of said second pairs of conjugated connection elements and said radial reliefs or teeth projecting circumferentially within said recesses.
5 . The annular cage according to claim 4 , wherein each said at least partially hemispherical cavity of each half-cage is bounded on its respective opposite circumferential sides by a first and a second axial lug, arranged adjacent to each other, projecting axially from the annular body of each half-cage, the first axial lug bearing in turn, axially projecting in series, one said male element consisting of said solid block and one said pin and the second axial lug being internally hollow and delimiting one said recess, from the interior of which axially departs a respective said hole which passes through the respective annular body until the hole crosses through said second frontal face; the opposite circumferential sides of respective adjacent pairs of said at least partially hemispherical cavities of the annular body of each said half-cage flanking respective opposite side walls of each said recess provided with said radial grooves, which are configured to snappingly mate circumferentially with said radial teeth or reliefs of the male elements or, conversely, provided with said radial teeth or reliefs which are configured to snappingly mate circumferentially with said radial grooves of the male elements.
6 . The annular cage according to claim 5 , wherein each said at least partially hemispherical cavity of the annular body of each half-cage is bounded axially, toward the second frontal face of the annular body, by a spherical back wall provided, toward the first frontal face of the annular body, with a depression axially developing in depth toward the second frontal face and having a circumferential extension, configured to constitute a lubricating grease containment chamber, so that in use, with the half-cages axially coupled, respective opposite sides of each of said seats or pockets for accommodating the rolling bodies are bounded by opposite lubricating grease containment chambers that are directly in contact with the rolling bodies at a median or primitive diameter of the rolling bearing.
7 . The annular cage according to claim 6 , wherein said spherical back wall of each of the at least partially hemispherical cavities is provided with a pair of radial grooves which are parallel to each other and are arranged close to opposite circumferential sides of each at least partially hemispherical cavity, configured to allow in use the circulation of lubricating grease within each said rolling body seat or pocket; and, in combination, said opposite circumferential sides of each at least partially hemispherical cavity are bounded on the side of said first frontal face of the annular body by opposite chamfers configured to form, with the half-cages axially coupled, opposite curved radial channels for lubricating grease circulation arranged peripherally around each said seat or pocket for the rolling bodies.
8 . The annular cage according to claim 7 , wherein each half-cage is provided radially on the outside thereof with a first radial annular ridge formed in proximity to said second frontal face of the annular body of each half-cage, so as to be axially distal from the seats or pockets for the rolling bodies; said first radial annular ridge of each half-cage being configured to go to mate in use within an annular groove obtained radially on the inside of the outer ring of the rolling bearing to exert with the outer ring a labyrinth seal function; a second radial annular ridge being optionally obtained radially on the inside of each half-cage, substantially flush with the first radial annular ridge, and being configured to go to mate in use within a second annular groove obtained radially on the outside of the inner ring of the rolling bearing to exert with the inner ring a labyrinth sealing function.
9 . The annular cage according to claim 8 , wherein said first radial annular ridge is provided radially on the outside with an axial relief obtained spaced apart, radially on the inside, from a radially outer peripheral edge of the first ridge having in radial section a curved profile.
10 . The annular cage according to claim 1 , wherein each said solid block constituting one said male element of said second pairs of conjugated connection elements is laterally provided, in a circumferential direction, with respective radial reliefs or teeth configured to snap-couple with respective radial grooves obtained within each said recess; or, conversely, the radial grooves being machined laterally on said solid blocks constituting said male elements of said second pairs of conjugated connection elements and said radial reliefs or teeth projecting circumferentially within said recesses.
11 . The annular cage according to claim 10 , wherein each said at least partially hemispherical cavity of each half-cage is bounded on respective opposite circumferential sides by a first and a second axial lug, arranged adjacent to each other, projecting axially from the annular body of each half-cage, the first axial lug bearing in turn, axially projecting in series, one said male element consisting of said solid block and one said pin and the second axial lug being internally hollow and delimiting one said recess, from the interior of which axially departs a respective said hole which passes through the respective annular body until the hole crosses through said second frontal face; the opposite circumferential sides of respective adjacent pairs of said at least partially hemispherical cavities of the annular body of each said half-cage flanking respective opposite side walls of each said recess provided with said radial grooves that are configured to snappingly mate circumferentially with said radial teeth or reliefs of the male elements or, conversely, provided with said radial teeth or reliefs which are configured to snappingly mate circumferentially with said radial grooves of the male elements.
12 . The annular cage according to claim 1 , wherein each said at least partially hemispherical cavity of the annular body of each half-cage is bounded axially, toward the second frontal face of the annular body, by a spherical back wall provided, toward the first frontal face of the annular body, with a depression axially developing in depth toward the second frontal face and having a circumferential extension, configured to constitute a lubricating grease containment chamber, so that in use, with the half-cages axially coupled, respective opposite sides of each of said seats or pockets for accommodating the rolling bodies are bounded by opposite lubricating grease containment chambers that are directly in contact with the rolling bodies at a median or primitive diameter of the rolling bearing.
13 . The annular cage according to claim 12 , wherein said spherical back wall of each of the at least partially hemispherical cavities is provided with a pair of radial grooves that are parallel to each other, the pair of radial grooves being configured to allow in use the circulation of lubricating grease within each said rolling body seat or pocket; and each at least partially hemispherical cavity having opposite circumferential sides bounded on the side of said first frontal face of the annular body by opposite chamfers configured to form, with the half-cages axially coupled, opposite curved radial channels for lubricating grease circulation arranged peripherally around each said seat or pocket for the rolling bodies.
14 . The annular cage according to claim 1 , wherein each half-cage is provided radially on the outside thereof with a first radial annular ridge formed in proximity to said second frontal face of the annular body of each half-cage, so as to be axially distal from the seats or pockets for the rolling bodies; said first radial annular ridge of each half-cage being configured to go to mate in use within an annular groove obtained radially on the inside of the outer ring of the rolling bearing to exert with the outer ring a labyrinth seal function; a second radial annular ridge being optionally obtained radially on the inside of each half-cage, substantially flush with the first radial annular ridge, and being configured to go to mate in use within a second annular groove obtained radially on the outside of the inner ring of the rolling bearing to exert with the inner ring a labyrinth sealing function.
15 . The annular cage according to claim 14 , wherein said first radial annular ridge is provided radially on the outside with an axial relief obtained spaced apart, radially on the inside, from a radially outer peripheral edge of the first ridge having in radial section a curved profile.
16 . A rolling bearing unit comprising:
a rolling bearing having an outer ring, an inner ring and a plurality of rolling bodies interposed between the inner and outer rings to make the inner and outer rings relatively rotatable with each other, and an annular cage retaining the rolling bodies and mounted interposed between the inner and outer rings; the annular cage comprising:
a plurality of pockets each bounded by a respective spherical surface having a center lying in a radial median plane of the cage coincident with a corresponding radial median plane of the rolling bearing;
two half-cages substantially symmetrical with respect to the median plane, and connected to each other, each half-cage presenting an annular body and a plurality of at least partially hemispherical cavities facing axially to the hemispherical cavities of the opposite half-cage to define the pockets; and
connection elements associated with the half-cages to constrain the two half-cages together to form said annular cage; characterized by the fact that said connection elements include, in combination:
first pairs of conjugate connection elements consisting, for each first pair, of a pin at least partially elastically deformable and of a respective hole configured to receive the pin snappingly, each half-cage being provided with a plurality of said pins projecting axially from the annular body on the side of a first frontal face of the annular body and of a corresponding plurality of holes formed axially in the annular body on the side of a second frontal face thereof, opposite to the first frontal face, the annular body of each half-cage being provided with said holes and said pins that are arranged in such a way that each pin of said half-cage mates with the hole facing the pin of the opposite half-cage through an opening of the hole facing the first face; and
second pairs of conjugate connection elements consisting, for each second pair, of a male element configured as a substantially rigid and solid block projecting axially from the first frontal face of the annular body of each half-cage, and of a corresponding recess configured to mate in integral manner with the solid block constituting the male element, the recess being obtained through the first frontal face of the annular body of each half-cage; each half-cage being provided with a plurality of said male elements and with a corresponding plurality of said recesses arranged so that each male element of said half-cage mates with said recess facing said male element of the opposite half-cage;
each pin projecting axially from a corresponding male element consisting of one said solid block, so as to be arranged axially in series with the one said solid block, downstream of the one said solid block with respect to said first frontal face of the annular body of each half-cage; and each recess being arranged axially in series with a respective said hole, upstream of said hole with respect to said first frontal face of the annular body of each half-cage;
each half-cage being provided radially on the outside with a first radial annular ridge formed in the vicinity of said second frontal face of the annular body of each half-cage, so as to be axially distal from the seats or pockets for the rolling bodies; said first radial annular ridge of each half-cage mating within an annular groove obtained radially on the inside of the outer ring of the rolling bearing to exert a labyrinth seal function with the outer ring; a second radial annular ridge being optionally obtained radially on the inside of each half-cage, substantially flush with the first radial annular ridge, and coupling within a second annular groove optionally obtained radially on the outside of the inner ring of the rolling bearing to exert with the inner ring a labyrinth sealing function.