Roller bearing seal assembly

In accordance with one aspect of the present disclosure, a rotor for a railway roller bearing seal assembly is provided. The rotor includes an annular body rotatable about a central axis and including radially inner and outer rings. The annular body includes an intermediate portion connecting the radially inner and outer rings and spacing the radially inner ring in a first direction from a base portion of the annular body. The annular body further includes a pocket formed at least in part by the intermediate portion and a snap-fit portion axially intermediate the base portion and a free end portion of the radially inner ring. The snap-fit portion of the annular body is configured to form a snap-fit connection with a snap-fit member of a slinger that extends into the pocket.

FIELD

This disclosure relates to railway roller bearings and, more specifically, to seal assemblies for railway roller bearings.

BACKGROUND

Railcars have undercarriage truck assemblies that include a frame, one or more wheel assemblies, and roller bearings that connect the wheel assemblies to the frame. Each wheel assembly includes an axle with journals at opposite ends thereof and wheels connected to the axle. Each roller bearing includes a first component mounted to the journal that turns with the journal and a second component that is mounted to the frame.

Various types of roller bearings are used for railcars. One type of roller bearing is a tapered roller bearing that includes one or more rows of tapered rollers. Tapered roller bearings, and other types of bearings, include a lubricant within the bearing to reduce resistance to movement between components of the bearing. Bearings may also include a seal to contain the lubricant within the bearing and to prevent water, dirt, and debris from entering the bearing.

One prior seal for a tapered roller bearing includes a seal case mounted to a bearing cup of the tapered roller bearing. The seal case includes an outer case and an insert press-fit in the seal case. The seal further includes a rotor mounted to a wear ring of a journal and a slinger connected to the rotor. During operation of the tapered roller bearing, the rotor and slinger rotate together relative to the seal case as the journal turns. Further, the assembly of the seal case, rotor, and slinger defines a labyrinth seal that resists egress of lubricant from the tapered roller bearing and the ingress of water and debris into the bearing.

The seal may be separately manufactured from the rest of the tapered roller bearing. In one prior approach, the seal case, rotor, and slinger are assembled at a first facility, transported to a second facility, and then subsequently assembled with a bearing cup and a wear ring of the tapered roller bearing at the second facility. More specifically, the outer case and insert of the seal case are assembled at the first facility by pressing the insert into the outer case. Next, the rotor is press-fit into the insert which fixes the rotor to the insert. The press-fit engagement between the rotor and the insert keeps the rotor assembled with the seal case and insert during transport. An annular inner wall of the slinger is then inserted into an opening of a slightly larger annular wall of the rotor to form a slip-fit connection therebetween. There is some nominal interference between the annular walls of the slinger and the rotor, but the slinger can shift relative to the rotor. The slinger may be made of a more pliable material than the rotor and the loose fit between the slinger and rotor permits the slinger to expand more than the rotor when the rotor/slinger assembly is subsequently press fit onto a wear ring. The assembled seal including the seal case, rotor, and slinger is packaged at the first facility and transported to the second facility.

After the seal has been transported from the first facility to the second facility, an operator at the second facility removes the seal from the package. The operator inserts the seal into a press machine and operates the press machine to press a wear ring into the slinger of the seal which expands the annular wall of the slinger into tight engagement with the annular wall of the rotor and inhibits relative rotary and axial movement between the rotor and slinger. The pressing of the wear ring into the slinger also shifts the rotor axially relative to the insert and disengages the press-fit engagement between the rotor and the insert which disconnects the rotor/slinger assembly from the insert/outer case assembly. Thus, the operation of press-fitting the wear ring into the slinger both secures the wear ring to the rotor/slinger assembly and disengages the rotor/slinger assembly from the insert/outer case assembly. This disconnecting operation permits the rotor/slinger assembly to turn relative to the insert/outer case assembly with turning of the journal. Although the disconnecting operation is necessary in the prior approach to permit the rotor/slinger assembly to turn, the disconnecting operation complicates assembly of the tapered roller bearing at the second facility.

Further, the rotor and the insert are made from an injection-molded plastic and the tolerances between the rotor and the insert may be too loose or too tight which adversely affects assembly and transportation of the seal. For example, if the rotor is too loosely engaged with the insert, the slip-fit connection between the rotor and the insert may permit the rotor and the slinger to fall off of the insert/seal case assembly when the seal is removed from the package at the second facility. If the rotor is too tightly engaged with the insert, the operation of press-fitting the wear ring into the slinger may cause the rotor to rip the insert out of the outer case.

Another issue with the prior seal is that the seals may be stacked for storage or stacked in a container for shipping. However, the stacked seals may fall over and become disorganized. A cardboard tube may be inserted into the aligned central openings of the stacked seals to inhibit tipping over of the stacked seals, but this complicates handling of the seals.

SUMMARY

In accordance with one aspect of the present disclosure, a rotor for a railway roller bearing seal assembly is provided. The rotor includes an annular body rotatable about a central axis, a base portion of the annular body, and a radially outer ring of the annular body extending axially from the base portion in a first direction and including a first free end portion. The annular body includes a radially inner ring extending axially in a first direction and having a second free end portion. The radially inner ring is spaced from the radially outer ring to receive a portion of a seal case therebetween. The annular body includes an intermediate portion connecting the radially inner and outer rings and spacing the radially inner ring in the first direction from the base portion. The annular body further includes a pocket formed at least in part by the intermediate portion and a snap-fit portion axially intermediate the base portion and the second free end portion of the radially inner ring. The snap-fit portion of the annular body is configured to form a snap-fit connection with a snap-fit member of a slinger that extends into the pocket. The snap-fit connection permits the rotor to be readily connected to a slinger about a seal case. Further, the pocket of the annular body receives at least a portion of the snap-fit member of the slinger to permit engagement of the rotor snap fit portion and the slinger snap-fit member in a compact envelope adjacent an associated wear ring.

The present disclosure also provides a slinger for a railway roller bearing seal assembly that includes an annular body rotatable about a central axis. The annular body has a radially inner ring with an opening sized to receive a wear ring and a radially outer ring spaced from the radially inner ring to receive a portion of a rotor between the radially inner and outer rings. The annular body includes an intermediate portion connecting the radially inner and outer rings and at least one radially outwardly extending protrusion of the radially inner ring configured to form a snap-fit engagement with the rotor. The slinger may thereby be connected to a rotor about a seal case via the snap-fit engagement which provides an easy-to-handle seal assembly.

In another aspect, a seal assembly for a railway roller bearing is provided that includes a seal case and a rotor and slinger rotatable relative to the seal case about a central axis. The rotor and slinger include interfering portions limiting axial movement of the rotor and slinger relative to one another in a first axial direction. The rotor and slinger have rings that tightly engage one another upon the rotor and slinger receiving a wear ring so that the rotor and slinger rotate with the wear ring. The rings include a free end portion and at least one stop surface that inhibit axial movement of the rotor and the slinger relative to one another in a second axial direction opposite the first axial direction. The interfering portions, free end portion, and at least one stop surface of the rotor and slinger cooperate to provide a fixed axial relationship between the rotor and slinger that maintains accurate dimensions of the seal assembly during assembly of the seal assembly with a roller bearing and during operation of the roller bearing.

The present application also provides a method of assembling a seal assembly for a railway roller bearing. The method includes positioning a rotor and a slinger on opposite sides of a seal case. The method includes positioning a ring of one of the rotor and the slinger between stop surfaces of the other of the rotor and the slinger. The method further includes engaging a snap-fit connection of the rotor and seal case that locks the ring between the stop surfaces and permits the rotor and slinger to rotate relative to the seal case. The method may thereby permit the rotor and slinger to be readily assembled with the seal case while, at the same time, permitting the rotor and slinger to rotate relative to the seal case once the seal assembly has been installed on a bearing cup of the roller bearing without requiring a pressing operation to disengage the rotor/slinger from the seal case.

DETAILED DESCRIPTION

With reference toFIGS.1and2, a roller bearing10is provided with bearing seal assemblies12that each include a seal case14, a rotor16, and a slinger17. The rotor16and slinger17may be assembled onto the seal case14and have a snap-fit connection18therebetween that connects the rotor16and slinger17and rotatably captures the rotor16and slinger17on the seal case14prior to assembly of the roller bearing seal assembly12with the other components of the roller bearing10. This improves handling of the roller bearing seal assembly12during transit and assembly with the other components of the roller bearing10. The snap-fit connection18improves handling of the roller bearing seal assemblies12because, once the snap-fit connection18is formed by advancing the rotor16and slinger17relative to one another (seeFIGS.10-13), the rotor16and slinger17are inhibited from falling off the seal case14. Once the rotor16and slinger17have been connected to the seal case14, the assembled seal case14, rotor16, and slinger17may be readily mounted to a bearing cup20and a wear ring44of the roller bearing10during assembly of the roller bearing10.

RegardingFIG.1, the roller bearing10includes bearing cones30that receive a journal32and are rotatable with the journal32about a central axis of rotation34. The roller bearing10includes one or more rows of tapered rollers36that travel along raceways37,38of the bearing cup20and the bearing cones30. A spacer ring40separates the bearing cones30. Thus, as the journal turns about the axis of rotation34, the bearing cones30and spacer ring40turn with the journal32and the tapered rollers36roll around the raceways37,38of the bearing cup20and the bearing cones30. The roller bearing10includes wear rings44on opposite sides of the bearing cones30and a backing ring50. The backing ring50has a curved surface52that engages a fillet54of the journal32. The roller bearing10further includes a retaining clamp58that is secured via fasteners such as bolts60to the journal32. When the bolts60are tightened down, the retaining clamp58clamps the wear rings44, bearing cones30, and spacer ring40together between the retaining clamp58and the backing ring50.

With reference toFIG.2, the seal case14is mounted to the bearing cup by way of a bead22engaged with a groove24of the bearing cup20. The seal case14may have a unitary, one-piece constructions or may include two or more assembled components. In one embodiment, the seal case14includes an outer case70and an insert72connected to the outer case70. The outer case70includes an outer portion74, an intermediate portion76, and an inner portion78. As used herein, the terms outer and inner generally refer to the relative radial position of the structure relative to the central axis of rotation34. Further, the term radially extending refers to extending at a right angle or obliquely to the axis of rotation.

RegardingFIG.2, the insert72may be press-fit into the outer case70. The outer case70may be made of a plastic or metallic material and the insert72may be made of a plastic material. The insert72has an outer portion, such as an outer ring80, engaged with the intermediate portion76of the outer case70and an inner portion, such as inner ring82.

The rotor16has an outer portion, such as an outer ring84, and an inner portion, such as an inner ring86. The rotor16further includes an intermediate portion, such as an intermediate wall88, connecting the outer and inner rings84,86. In one embodiment, the inner wall88has a frustoconical shape. The rotor16may be made of a plastic or metallic material and may have a unitary, one-piece construction.

RegardingFIG.2, the inner wall88imparts an axial offset to the inner ring86relative to the outer ring84. More specifically, the rotor16has a base portion90with a surface92that seats against a surface94of the bearing cone30and the intermediate wall88extends axially from the surface92to position a shoulder96of the rotor16axially spaced from the surface92of the rotor base portion90. The terms axial and axially extending as used herein are intended to refer to having an extent along the axis of rotation34and may refer to a component that is intersected by the axis or spaced from the axis. The shoulder96may have a generally radial, projecting shape that transitions from a frustoconical surface100of the intermediate wall88to a surface102of the shoulder96. In one embodiment, the surface102extends normal to the axis of rotation. The shoulder96may extend continuously without interruption around the rotor16and form an interior rim of the rotor16.

In one embodiment, the rotor16has a snap-fit member, such as the shoulder96, that engages a corresponding snap-fit member of the slinger17. For example, the slinger17may include a protrusion, such as a barb104, that is in an axially overlapping relation with the shoulder96once the slinger17has been connected to the rotor16(seeFIG.2). The slinger17includes an outer portion, such as an outer ring110, an intermediate portion, such as an intermediate wall112, and an inner portion, such as an inner ring114. The slinger17, seal case14, and rotor16cooperate to form a tortuous path116of the roller bearing seal assembly12. The tortuous path116limits egress of lubricant from the roller bearing10and inhibits ingress of dirt and debris from the surrounding environment into the roller bearing10. The slinger17may be made of a plastic or metallic material.

RegardingFIG.3, the seal case14has an opening120to receive one of the wear rings44and the journal32. The inner ring114of the slinger17forms a radially innermost section of the roller bearing seal assembly12and includes tabs122for extending along the wear ring44. The tabs122include the outwardly extending barbs104that form the snap-fit connection18with the shoulder96of the rotor16. As discussed with reference toFIGS.10-13, the tabs122may be resilient and deflect radially inward to permit the barbs104to deflect around the inner ring86of the rotor16as the rotor16and slinger17are connected and permit the barbs104to snap behind the shoulder96once the rotor16and slinger17have been advanced together.

RegardingFIG.4, the rotor16has an annular body124that includes the outer ring84, inner ring86, and a recess126therebetween that receives at least a portion of the inner ring82of the insert72. The annular body124includes a central opening128that receives the inner ring114of the slinger17. The insert72includes a central opening130that receives the inner ring86of the rotor16and the inner ring114of the slinger17. The outer case70includes a central opening132that receives the insert72. The slinger17includes an annular body134having a central opening136for receiving the wear ring44.

RegardingFIG.5, the rotor16may have a step profile connecting the outer ring84and the inner ring86. In one embodiment, the rotor16includes a juncture140connecting the intermediate wall88and the inner ring86. In one embodiment, the juncture140includes a substantially right angle between a radial portion142and the inner ring86. The juncture140may include the shoulder96and the surface102thereon that are in axial overlapping relation with a stop surface, such as surface146, on the underside of the barb104. Because the surfaces146,102overlap along the axis of rotation34, the confronting surfaces146,102inhibit axial movement of the rotor16in direction150.

The slinger17includes one or more stops153that contact a free end portion160of the rotor inner ring86to inhibit axial movement of the rotor16in direction152. In this manner, the inner ring86of the rotor16is locked between the barbs104and the stops153of the slinger17once the barbs104have snapped behind the shoulder96of the rotor16as shown inFIG.5.

More specifically, the stops153may include projections, such as walls154, having one or more stop surfaces156thereon. The inner ring86of the rotor16is received in a recess166(seeFIG.9) of the slinger17between the barbs104and the stop surfaces156of the walls154. RegardingFIG.5, the free end portion160of the rotor inner ring86includes an inclined surface162that terminates at a point164. The free end portion160may be in abutting contact with the stop surfaces156when the rotor16connected to the slinger17. The confronting relation between the free end portion160of the rotor inner ring86and the stop surfaces156of the slinger17inhibits movement of the rotor16in direction152relative to the slinger17.

InFIG.5, there is a small radial gap170shown between the inner ring86of the rotor16and the inner ring114of the slinger17. The gap170facilitates connecting of the rotor16and slinger17during assembly of the roller bearing seal assembly12. However, the wear ring44may be pressed into the opening136of the slinger17during assembly of the roller bearing seal assembly12and the wear ring44. The pressing of the wear ring44into the slinger17radially expands the inner ring114of the slinger17into tight engagement with the inner ring86of the rotor16and closes the radial gap170.

RegardingFIGS.9and10, the tight engagement caused by pressing the wear ring44into the slinger17urges a radially outer surface180of the slinger inner ring114radially outward against a radially inner surface182of the rotor inner ring86. RegardingFIG.2, with the rotor inner ring86tightly frictionally engaged with the slinger inner ring114, rotation of the wear ring44causes rotation of both the slinger17and the rotor16. In this manner, the rotor16is fixed in axial directions150,152relative to the slinger17by way of the barbs104and walls154as well as being rotationally fixed to the slinger17by way of the engagement between the inner rings86,114. The fixed axial positioning of the rotor16and slinger17accurately positions the rotor16relative to the seal case14once the slinger17and wear ring44therein are seated against the bearing cone30and provides accurate dimensions of the tortuous path116.

RegardingFIGS.6and7, the tabs122are angularly spaced apart on the inner wall114by angular or circumferential gaps190of the inner wall114. The walls154are also angularly spaced apart by circumferential gaps191around the intermediate wall112. The walls154provide the stop surfaces156while having a relatively uniform material thickness which may facilitate injection molding of the slinger17. The intermediate wall112may have one or more raised portions192angularly spaced about the intermediate wall112. The raised portions192may operate as a bumper against the outer case70and form line contacts therewith that minimize the frictional resistance between the slinger17and the outer case70. In other embodiments, the intermediate wall112does not include raised portions192.

RegardingFIG.8, the slinger17includes a projection, such as a bead200, on an opposite side of the intermediate wall112from the inner ring114. The bead200includes a tapered surface202that has a similar taper as an inclined surface204(seeFIG.5) of the barbs104. RegardingFIG.14, when the slingers17are stacked for transport, the barbs104of the upper slinger17A seat against the bead200of the lower slinger17B. The nested surfaces202,204resist relative radial movement of the slingers17A,17B and keep the slingers17A,17B coaxially aligned and in a stacked configuration. In other embodiments, the bead200may be radially outward from the position shown inFIG.8and/or may be discontinuous about the slinger17.

RegardingFIG.9, the underside surfaces146of the barbs104are spaced an axial distance210from the stop surfaces156of the walls154. The distance210is slightly larger than an axial length214(seeFIG.10) of the inner ring86of the rotor16. The distance210is selected to be slightly larger than the length214to permit the inner ring86to fit into the recess166and to permit the barb104to snap behind the shoulder96of the rotor16as discussed in greater detail below.

RegardingFIG.10, the surface92of the rotor base portion90is spaced an axial distance220from the surface102of the shoulder96by the intermediate wall88. The axial and radial offsets between the surfaces92,102forms a recess or pocket222that receives the barb104once the rotor16and slinger17have been assembled onto the seal case14(seeFIG.5). Prior to assembly of the rotor16and the slinger17, and with reference toFIG.15, the rotors16A,16B may be stacked with the pocket222of the upper rotor16A receiving the free end portion160of the lower rotor16B. The free end portion160of the lower rotor16B supports the shoulder surface102of the upper rotor16A. The outer ring84of the lower rotor16B has a free end portion224that supports the base portion surface92of the upper rotor16A. Further, the overlap in a radial direction of the inner ring free end portion160of the lower rotor16B and the intermediate wall88of the upper rotor16A inhibits radial relative movement of the rotors16A,16B and keeps the rotors16A,16B coaxially aligned in a stacked configuration.

RegardingFIGS.10-13, a method of assembling the roller bearing seal assembly12will be provided. RegardingFIG.10, the insert72has been assembled with outer case70and the rotor16is positioned so that the inner ring86of the rotor16is aligned with the opening130of the insert72. The rotor16may be advanced in direction152to position the inner ring82of the insert72in the recess126between the outer ring84and the inner ring86of the rotor16, as shown inFIG.11.

RegardingFIG.11, the slinger17is positioned so that the inner ring114is aligned with the opening128of the rotor16. The slinger17has a recess232between the outer ring110and the inner ring114to receive portions of the seal case14and rotor16. The inclined surfaces204of the barbs104are aligned with the inclined surface162of the free end portion160of the rotor inner ring86and the slinger17is advanced in direction150relative to the rotor16. It will be appreciated that the movement of the slinger17in direction150relative to the rotor16may be accomplished by moving the slinger17while the rotor16remains stationary, moving the rotor16while the slinger17remains stationary, or moving both the rotor16and slinger17.

RegardingFIG.12, the surfaces162,204cammingly engage with advancing of the slinger17in direction150and deflect the barb104radially inward. In one embodiment, the tabs122each include a free end portion240and a base portion242. The camming engagement between the surfaces162,204deflects the free end portions240of the tabs122radially inward and bends the base portion242of the tabs122to permit the barbs104to shift radially inward. RegardingFIG.5, the free end portion240of the tab122has a surface241that abuts against the bearing cone surface94when the slinger17and wear ring44are seated against the bearing cone30.

RegardingFIG.13, the barbs104have been shifted inwardly and are advancing along the radial inner surface182of the rotor inner ring86as the slinger17is continued to be advanced in direction150. The slinger17is advanced in direction150until the barb40is advanced past the shoulder96. Once the barb104has been advanced axially beyond the shoulder96of the rotor16, the tabs122may resiliently rebound and shift generally outward in direction245. The resilient unloading of the tabs122positions the barbs104in axially overlapping relation with the shoulder96of the rotor16as shown inFIG.5.

In one embodiment, the shoulder96is continuous around the rotor16. The barbs104may form the snap-fit connection18with the shoulder96at any rotary position of the slinger17relative to the rotor16. In other words, the slinger17may not have to be rotationally positioned in a specific orientation relative to the rotor16before advancing the slinger17in direction150to connect the slinger17with the rotor16. This may make assembly of the rotor16and the slinger17easier by permitting connection of the rotor16and slinger17at any rotary position of the two parts as the parts are shifted axially together.

RegardingFIG.13, the insert72has an intermediate wall260, a connecting wall such as frustoconical wall portion262, and the inner ring82. The frustoconical wall portion262creates a radial and axial offset between the intermediate wall portion and the ring82. The offset forms a pocket264that provides clearance for the walls154of the slinger17to rotate relative to the insert72.

RegardingFIG.16, the inserts72A,72B are shown in a stacked configuration. The inner ring82of the insert72A has a free end portion270that is received in the pocket264of the insert72B and is supported by a surface272of the insert72B. The free end portion270of the insert72A is near the frustoconical wall portion262of the insert72B such that contact between the free end portion270and frustoconical wall portion262inhibits radial shifting of the inserts72A,72B and keeps the inserts72A,72B coaxially aligned in the stacked configuration.

RegardingFIG.17, once the roller bearing seal assembly12has been assembled, the roller bearing seal assembly12has features that permit the roller bearing seal assembly12to be stacked with other roller bearing seal assemblies12. For example and with reference toFIG.17, the roller bearing seal assembly12A is stacked on the roller bearing seal assembly12B. The base portion surface92of the rotor16of the roller bearing seal assembly12A is supported on the intermediate wall112of the slinger17of the roller bearing seal assembly12B. Further, the bead200of the roller bearing seal assembly12B extends into the pocket222of the roller bearing seal assembly12A. The bead200overlaps in the radial directions with the intermediate wall88of the rotor16and the inner ring114of the slinger17of the roller bearing seal assembly12A. The radially overlapping relation between the intermediate wall88, the bead200, and the inner ring114inhibits radial shifting of the roller bearing seal assemblies12A,12B and keeps the roller bearing seal assemblies12A,12B coaxially aligned and in the stacked configuration.

RegardingFIG.18, another roller bearing seal assembly300is provided that is similar in many respects to the roller bearing seal assembly12discussed above such that differences will be highlighted. The roller bearing seal assembly300includes a seal case302including an outer case304and an insert306. The roller bearing seal assembly300further includes a slinger308and a rotor310. The rotor310includes a base portion312having a surface314. The slinger308includes an inner ring316having one or more barbs318, one or more free end portions320, and one or more surfaces322of the free end portions320that seat against a bearing cone. The surfaces322are axially spaced a distance324from the surface314. The axial spacing creates an axial gap325between the surface314of the rotor310and the bearing cone, which may be desirable in some circumstances. The rotor310may include an intermediate wall328that has a shorter axial extent than the intermediate wall88discussed above due to the axial offset between the surfaces314,322.

RegardingFIG.19, an outer case350is provided that is similar in many respects to the outer cases70,304discussed above such that differences will be highlighted. The outer case350includes outer portion352having a bead354, an intermediate portion356, and an inner portion358. The intermediate portion356includes a radial wall portion358, a frustoconical wall portion360, and an axial wall portion362.

Uses of singular terms such as “a,” “an,” are intended to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. The terms “comprising,” “having,” “including,” and “containing” are to be construed as open-ended terms. It is intended that the phrase “at least one of” as used herein be interpreted in the disjunctive sense. For example, the phrase “at least one of A and B” is intended to encompass A, B, or both A and B.

While there have been illustrated and described particular embodiments of the present invention, it will be appreciated that numerous changes and modifications will occur to those skilled in the art, and it is intended for the present invention to cover all those changes and modifications which fall within the scope of the appended claims. The seals discussed herein may be utilized in various railway applications, such as for bearings of locomotives, rail cars, and rail service vehicles.