This invention relates to shaft journal bearings and, more particularly, to an improved bearing assembly spacer supporting arrangement for use in a railway freight car.
Roller bearing assemblies incorporating two rows of tapered roller bearings preassembled into a self-contained, pre-lubricated package for assembly onto journals at the ends of axles or shafts are known. Such bearing assemblies are used as rail car bearings assembled onto journals at the ends of the axles. Bearings of this type typically employ two rows of tapered roller bearings fitted one into each end of a common bearing cup with their respective bearing cones having an inner diameter dimensioned to provide an interference fit with the shaft journal and with a cylindrical sleeve or spacer positioned between the cones providing accurate spacing and proper lateral clearance on the journal. Seals mounted within each end of the bearing cup provide sealing contact with wear rings bearing against the outer ends or back face of the respective bearing cones at each end of the assembly. Such seals are shown in U.S. Pat. Nos. 5,975,533, 7,607,836, and 7,534,047.
In a typical rail car installation, the axle journal is machined with a fillet at the inboard end. A backing ring having a surface complementary to the contour of the fillet and an abutment surface for engaging the inboard end of an inner wear ring accurately position the bearing assembly on the journal. An end cap mounted on the end of the axle by bolts threaded into bores in the end of the axle engages the outboard wear ring and clamps the entire assembly on the end of the axle. The wear rings typically have an inner diameter dimensioned to provide interference fit with the journal over at least a portion of their length so that the entire assembly is pressed as a unit onto the end of the journal shaft portion of the axle.
It is desirable to assure the support and proper spacing of the cones by assuring the support and positioning of the spacer.
The bearing assembly of the present invention is a roller bearing that includes an inner race or cone fitted around the journal portion of the axle or shaft. The inner race formed by the cones includes an outwardly directed raceway. An outer race or cup has an inwardly directed raceway. Roller elements are located between and contacting the inner and outer raceways.
A backing ring has a contoured surface complementary to and engaging the contoured surface of a fillet formed on the shaft. The fillet leads from the journal to the shoulder of the shaft. The contoured surfaces cooperate to fix the backing ring against axial movement along the shaft.
The bearing assembly includes a seal assembly that provides a barrier for lubricant to be retained within the seal assembly and for contaminants to be kept out. A spacer is provided to assure the proper spacing of the two cones. A spacer support is provided to assure the proper positioning and support of the spacer during shipping and installation. The spacer support can remain in place after installation of the bearing assembly on an axle.
In the drawings,
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Bearing assembly 10 is preassembled before being mounted and clamped on journal 12 by retaining cap 30 and bolts 28. The bearing assembly includes a unitary bearing cup or outer raceway 32 having a pair of inner facing raceways 34,36 formed one adjacent each end thereof which cooperate with a pair of bearing cones 38,40, having outer facing raceways respectively, to support the two rows of tapered rollers 42,44, respectively there between. A center spacer 46 is positioned between cones 38, 40 to maintain the cones in accurately spaced position relative to one another allowing for proper bearing lateral clearance.
Spacer support 72 is seen as a generally cylindrical unitary structure usually comprised of a plastic, such as a high density polyethylene. Spacer support 72 has a radially inner edge adjacent radially outward facing outer surface 73 of spacer 46. Spacer support 72 has a radially outer edge adjacent a radially inward facing center section 71 of cup 32. Spacer support 72 inner edge may engage or contact radially outward facing outer surface 73 of spacer 46.
Spacer support 72 outer edge 79 may engage or contact radially inward facing counter section 71 of cup 32. Whether or not actual contact is present, spacer support 72 acts to position and hold spacer 46 in position between cones 38 and 40 during shipping and assembly of bearing assembly 10. Spacer support 72 may initially upon installation for shipping contact both radially inward facing center section 71 of cup 32 and radially outward facing outer surface 73 of spacer 46, and after installation and wear in service, may contact one, both, or neither.
Bearing cup 32 is provided with cylindrical counterbores 17,19 at its axially outer ends and a pair first end sections 48, 50 of seal sections 52,54 are pressed one into each of the cylindrical counterbores 17,19 in cup 32. Each second end section 55, 63 of seal section 52,54 may include resilient sealing elements 56, 58 which rub upon and form a seal with radial outer surfaces 37,61 of a pair of seal wear rings 60,62 having an inwardly directed end in engagement with the outwardly directed ends of bearing cones 38,40 respectively. Seal section 54 is similar to seal section 52 and will not be described in detail. The other end of wear ring 60 is received in a cylindrical counterbore 64 in the axially outwardly directed end of an annular backing ring 66 which, in turn, has a counterbore 68 at its other end which is dimensioned to be received in interference and non-interference relation on the cylindrical shoulder 18 of shaft 14. The counterbore 64 and the outer diameter of wear ring 60 are also dimensioned to provide an interference fit so that wear ring 60 is pressed into the backing ring 66 which is accurately machined to provide a contoured inner surface 70 complementary to and engaging the contour of fillet 22 when the bearing is mounted on the shaft. The outwardly directed end of wear ring 62 bears against a counterbore 31 in a retaining cap 30.
Referring now to