Cage and roller assembly
A cage and roller assembly includes a plurality of rollers to be brought into rolling contact with a raceway surface provided on the outer periphery of a shaft, and an annular cage that retains the rollers. Lubricating oil is supplied through an oil supply hole that is provided inside the shaft and is open at the raceway surface. The cage includes a pair of annular portions, and a plurality of cage bars that couple the annular portions together and are arranged with intervals in a circumferential direction. The rollers are housed in pockets each formed between the pair of annular portions and between the cage bars that are adjacent to each other in the circumferential direction. The cage has an inner recessed groove that is provided on a radially inner surface of the cage bar and extends through the annular portions in an axial direction.
1. A planetary gearing mechanism, comprising:
a planetary gear, and a support structure that supports the planetary gear, wherein:
the support structure comprises (i) a carrier and (ii) a cage and roller assembly;
the carrier comprises a disc-shaped body, a shaft, and a retaining member;
a first side washer is provided between (i) the disc-shaped body and (ii) the cage and roller assembly and the planetary gear;
a second side washer is provided between (i) the retaining member and (ii) the cage and roller assembly and the planetary gear;
the cage and roller assembly comprises:
a plurality of rollers configured to roll along a raceway surface provided on an outer periphery of the shaft; and
an annular cage that retains the rollers;
the first and second side washers are located axially adjacent to the cage,
an oil supply hole is provided inside the shaft and is open at the raceway surface,
the cage includes:
a pair of annular portions;
a plurality of cage bars that couple the pair of annular portions together and are arranged at intervals in a circumferential direction;
the rollers are housed in pockets each formed between the pair of annular portions and between the cage bars that are adjacent to each other in the circumferential direction, and
the cage has inner recessed grooves, each inner recessed groove being provided on a radially inner surface of a respective one of the cage bars and extending through the annular portions in an axial direction;
the cage further includes:
an annular recess provided on an axially outer side and a radially inner side of one of the annular portions, the inner recessed grooves being open at the annular recess; and
an annular protrusion that is provided on a radially outer side of the annular recess and includes a face adjacent to one of the first and second side washers located axially adjacent to the cage.
2. The planetary gearing mechanism according to claim 1 , wherein
a diameter of an inner peripheral surface of the annular protrusion is larger than a diameter of an imaginary circumscribed circle passing through groove bottoms of a plurality of the inner recessed grooves, and
a face of the annular recess where the inner recessed grooves are open has a flat surface portion on a radially outer side of open ends of the inner recessed grooves.
3. The planetary gearing mechanism according to claim 1 , wherein
a radial dimension of the face of the annular protrusion is 50% or more of a radial dimension of one of the annular portions.
4. The planetary gearing mechanism according to claim 1 , wherein a difference between a radius of an imaginary inscribed circle passing through the radially inner surfaces of the plurality of cage bars and a radius of the shaft is 0.5 millimeters or smaller.
5. The planetary gearing mechanism according to claim 1 , wherein
the cage is guided by the planetary gear located on a radially outer side of the cage.
6. The planetary gearing mechanism according to claim 1 , wherein each of the cage bars has one of the inner recessed grooves.