Patent Description:
Tapered roller bearings on railcar axles support operating loads capable of producing deflections in the axle, and in particular, the end portion of the axle comprising the journal on which the tapered roller bearing is affixed. The stresses imposed by the operating loads are particularly high in the journal portion of the shaft at or near the backing ring.

As result of shaft deflections, the backing ring and the journal often experience fretting wear as the backing ring moves relative to the journal. Fretting wear may be sufficient to loosen the backing ring, increasing the axial play of the bearing on the journal. The loose backing ring accelerates wear on the bearing assembly and journal, potentially leading to shaft or bearing failure.

It is desirable to retain lubricants in the form of oils or grease within the bearing while also excluding water and abrasives. Such lubricants are held within the bearing by means of a bearing seal, that is a generally ring shaped structure that usually includes a resilient seal member.

<CIT> discloses a method of manufacturing a bearing seal according to the preamble of claim <NUM>.

It is an object of the present invention to provide an improved method for the manufacture of a bearing seal.

The present invention provides an improved method of manufacturing a bearing seal component for a tapered roller bearing designed to be fitted on railway freight car axle. The method of the present invention is a significant improvement over the currently known methods which usually involve a stamping operation having several steps requiring dedicated stamping equipment and result in a significant amount of scrap. The method of the present invention involves the use of a sheet of steel, which is the usual material of which a bearing seal is comprised, of the exact width in material needs of the finished bearing seal, such sheet of steel cut and run is initially through a ring forming machine. The formed ring is then welded, and run through the necessary number of pre-forming operations to result in a final formed bearing seal. The method of the present invention is seen to be an improvement from a material use and efficiency point of view.

Referring to <FIG>, an embodiment of the backing ring assembly manufactured in accordance with the present invention is illustrated. In this embodiment, the bearing assembly <NUM> is a tapered roller bearing of the type commonly used in railway applications to support a railcar wheel on an axle.

The bearing assembly <NUM> is typically preassembled before being mounted on railcar axle <NUM>. At each free end of the axle <NUM>, a journal <NUM> terminates in a slightly conical tapered section <NUM> to facilitate installation of the bearing assembly <NUM> onto the journal. The bearing assembly <NUM> is pressed onto the journal <NUM> of the axle <NUM> to establish an interference fit.

A dust guard <NUM> with a larger diameter than the journal <NUM> is located axially inward from the journal <NUM>. Axially inward from the dust guard <NUM>, the shaft <NUM> extends to its largest diameter. The weight of the railcar is transferred through the bearing assembly <NUM> to the shaft and further transferred to the rails through the railcar wheels (not shown) fitted inboard of the dust guard on the shaft.

Some bearing assemblies <NUM> have wear rings <NUM>, <NUM> fitted over the journal <NUM> and which about each end of the bearing assembly <NUM>. The wear rings <NUM>, <NUM> typically have an inner diameter dimension to provide an interference fit with the journal <NUM> over at least a portion of their length. The wear rings <NUM>, <NUM> rotate with the shaft as it turns.

Although the bearing assembly <NUM> is pressed onto the journal <NUM>, further restraint is generally required against axial loads. To provide this axial restraint, the bearing assembly <NUM> is captured between a backing ring assembly <NUM> at the inboard side and a bearing retaining cap <NUM> at the outboard side of the bearing assembly <NUM>.

Referring now to FIG. <NUM> as well, at the inboard side of the journal <NUM> portion of axle <NUM>, the bearing assembly <NUM> is captured by the backing ring <NUM> through abutting wear ring <NUM>. Backing ring <NUM> has an inner contoured surface <NUM> allowing a tight surface fit with a complementary surface on the fillet <NUM> on the inboard end of the journal <NUM>. The fillet <NUM> leads to a shoulder <NUM>, the shoulder extending to form a dust guard <NUM> having a cylindrical surface <NUM>. Backing ring <NUM> has an inboard distal edge <NUM> at the contoured surface <NUM>, generally abutting fillet <NUM>.

Locking ring <NUM>, has a lateral inner end adjacent to the dust guard <NUM>. Locking ring lateral outer end engages backing ring <NUM> and restrains backing ring <NUM>, against deflection and axial displacement. Backing ring <NUM> and locking ring <NUM> together form the backing ring assembly <NUM>. Locking ring <NUM>, the furthest inboard component affixed to the journal <NUM>, affixes the bearing assembly <NUM> against axially inward displacement.

At the outboard end of the journal, the bearing assembly <NUM> is captured by the bearing retaining cap <NUM> through the interposed and abutting outboard wear ring <NUM>. Bearing retaining cap <NUM> is affixed to the free end of journal <NUM> with cap screws or bolts <NUM> threaded into a plurality of threaded bores. Bearing retaining cap <NUM> completes the mounting of the bearing assembly <NUM> onto the journal <NUM>, providing a clamping force to restrain the bearing assembly against axially outward displacement.

The bearing assembly <NUM> is preassembled from a number of individual components, including two cylindrical bearing cones <NUM>,<NUM> and a cylindrical bearing cup <NUM>. Bearing cup <NUM> has an inner surface having radially inward directed outer raceways <NUM>, <NUM>. The bearing cones <NUM>, <NUM> have radially outward directed inner raceways <NUM>, <NUM>. A center spacer <NUM> is positioned between the bearing cones <NUM>, <NUM> to maintain the cones in accurately spaced position relative to each other and allow for proper bearing lateral clearance. The outer raceways <NUM>, <NUM> in the bearing cup <NUM> cooperate with the inner raceways <NUM>, <NUM> in the bearing cones <NUM>, <NUM> to capture and support two rows of the tapered rollers <NUM>, <NUM>. In some embodiments, cages <NUM>, <NUM> maintain the circumferential spatial positioning of the rollers <NUM>, <NUM>.

Bearing seals <NUM>, <NUM> cover the ends of the bearing assembly <NUM> to minimize both lubricant leakage from the bearing and intrusion of contaminants such as water or abrasives into the bearing. In a first embodiment, the bearing seals <NUM>, <NUM> are affixed to the stationary (i.e., non-rotating) side of the bearing assembly <NUM> (such as the bearing cup <NUM>) by interference fit or other appropriate method.

A seal body <NUM>, typically of a generally ring shaped steel construction, is part of bearing seal <NUM>, <NUM> to form a dynamic seal between stationary and moving bearing assembly components. In one embodiment, the seal body <NUM> is urged against the wear ring <NUM>, <NUM> to seal the bearing assembly <NUM>. A first radial edge <NUM> of seal body <NUM> is received against an inner radial surface <NUM> of bearing cup <NUM>. A second radial edge <NUM> of seal body <NUM> extends radially inward and has a resilient seal <NUM> attached thereto. Resilient seal <NUM> contacts outer radial surface <NUM> of wear ring <NUM> and is typically comprised of a rubber or synthetic flexible material.

Cylindrical wear rings <NUM>, <NUM> protect the journal <NUM> against rubbing wear from the seal body by providing a wear surface <NUM>.

Referring to FIG. <NUM>, the backing ring assembly <NUM> of <FIG> is illustrated in an enlarged sectional view. Backing ring <NUM> has an inner contoured surface <NUM> adjacent the journal <NUM> at the complementary surface of the fillet <NUM>.

A slot or cutout section <NUM> in the axially inward directed surface of backing ring <NUM> receives the laterally inner end <NUM> of wear ring <NUM> in an interference fit.

Locking ring <NUM> further has a lateral outer end <NUM> of a larger diameter and having a cutout section <NUM> for receiving a radially outward extending portion <NUM> of backing ring <NUM>. Locking ring <NUM> outer end <NUM> includes an inner radial surface <NUM> that is adjacent outer radial surface <NUM> of backing ring <NUM>. Locking ring <NUM> inner end <NUM> includes an inner radial surface <NUM> that is adjacent outer radial surface <NUM> of axle <NUM>.

Locking ring <NUM>, with its connection between backing ring <NUM> and the cylindrical surface <NUM> of the dust guard <NUM>, reinforces and anchors backing ring <NUM> against axial displacement and deflection. It is believed that the flexibility of the locking ring <NUM> allows backing ring <NUM> to more readily move with the deflection of the journal <NUM>, yet, still allow locking ring <NUM> to restrain the axial displacement of backing ring <NUM>.

Referring now to FIG. <NUM> and FIG. <NUM>, the currently known method for forming a bearing seal or bearing seal case is to stamp the bearing seal case from a flat rolled coil of steel <NUM>. It is noted that the width of the flat rolled coil of steel <NUM> is wider than the diameter of the material needed to form the final bearing seal case <NUM>. The seal case itself is an important component of the entire bearing assembly in that the seal case is utilized to both retain lubricant within the moving components of the bearing assembly and to keep undesired components such as rainwater and dirt out of the moving components of the bearing assembly.

The process currently utilized to manufacture bearing seal case <NUM> is known as a drawing process, wherein the bearing seal is formed in a progressive die stamping operation. These progressive operations are generally shown in FIG. <NUM>, with a first stamping operation forming a pre-form bearing seal <NUM>, a second stamping operation forming a second pre-form bearing component <NUM>, and a final stamping operation forming a final bearing seal <NUM>. It is seen that a waste portion of steel <NUM> ultimately is released during the final forming operation, with initial centrally located steel components from the initial stamping shown as <NUM>, central component <NUM> in the second pre-forming operation, and central component <NUM> formed in the third stamping operation. The ultimate amount of waste product from the known bearing stamping operation is shown in FIG. <NUM> as center component <NUM> and leftover portion <NUM> of coil <NUM>. It is an important object of the present invention to provide a more efficient method of manufacturing a bearing seal component. In the second forming operation wherein bearing component <NUM> is restruck, the seal case <NUM> is given an initial start of its final geometry. The next operation is a piercing operation wherein bearing seal <NUM> is coined to its final form. Bottom portion <NUM> is cut and pressed back into the seal case to be carried to the final forming operation. In the final operation, the pierced bottom section or waste section <NUM> is removed from bearing seal <NUM>.

Referring now to FIG. <NUM>, a finished bearing seal case manufactured in accordance with an embodiment of the present invention is shown generally at <NUM>. Bearing seal case <NUM> is seen to comprise an inner diameter <NUM> which is typically the inner diameter of a strengthening lip that begins at pre-form or bent section <NUM>. Inner diameter section <NUM> is seen to be at about a <NUM>° angle to main bearing seal case section <NUM>. Outer diameter <NUM> is formed as a lip with an initial transfer step <NUM> extending from main section <NUM> and ending with a transverse section <NUM> to form outer diameter <NUM>.

Referring now to FIG. <NUM> - FIG. <NUM>, the method of forming bearing seal case <NUM> in accordance with an embodiment of the present invention is set forth. Steel coil <NUM> is fed into a ring rolling machine <NUM> which is comprised of sets of rollers. Steel coil <NUM> is formed into a closed coil ring <NUM>, which is cut from steel coil <NUM>. Closed coil ring <NUM> is welded with weld fixture <NUM> in place.

Referring now to FIG. <NUM>, closed coil ring <NUM> is shown as being transferred to weld bead removal station <NUM>.

The weld bead formed on welded steel coil ring <NUM> is flattened in the operation shown in FIG. <NUM> by passing welded steel coil ring <NUM> through flattening rollers <NUM> and <NUM>.

Referring now to FIG. <NUM>, an initial pre-form operation to welded steel coil ring <NUM> is pre-formed utilizing the combined rollers <NUM> and <NUM> mounted on rolling machine <NUM> with a base <NUM>. This forms a profile at a ninety degree angle to welded steel coil ring <NUM> as shown in the included profile of FIG.

Referring now to FIG. <NUM>, a second pre-forming operation is performed to the first pre-formed steel coil ring <NUM>, by a pre-forming roller <NUM> combined with an outer shaping roller assembly <NUM>. This introduces two additional ninety degree bends or near ninety degree bends in first pre-form steel coil ring <NUM> as shown in the included profile of FIG.

A third pre-forming operation can be included as shown in FIG. Such third pre-forming operation is performed to a second pre-formed steel coil ring <NUM> by a combination of an internal roller assembly <NUM> and an external roller form <NUM>. This third pre-forming operation depends on the ultimate desired profile of bearing seal <NUM>.

Referring now to FIG. <NUM>, a final pre-forming operation is performed wherein the final configuration of bearing seal <NUM> is formed utilizing a combination of tapered key <NUM> and segmented die <NUM>. Such forming operation results in the formation of finished bearing seal <NUM> to its final configuration. It will be noted from the above steps that no waste material is formed from the initial width of steel coil <NUM> to the final configuration of bearing seal <NUM>.

Claim 1:
A method of manufacturing a bearing seal (<NUM>) comprising the steps of:
feeding a steel coil (<NUM>) of a preselected width into a ring rolling machine (<NUM>), cutting a divided length of the steel coil and rolling the length of steel coil into a closed coil ring (<NUM>) having a butted joint,
the butted joint of the closed coil ring (<NUM>) is welded to form a welded steel coil ring (<NUM>), transferring the welded steel coil ring to a weld bead removal station (<NUM>), then transferring to a weld flattening machine wherein any weld bead at the butted joint between the two cut ends of the steel coil ring is flattened to form a flattened steel coil ring, transferring the flattened steel coil ring to a first pre-forming machine (<NUM>) wherein a first profile is formed in the flattened steel coil ring to form a first profiled steel coil ring (<NUM>), transferring the first profiled steel coil ring (<NUM>) to a second pre-forming machine wherein a second profile is formed in the first profiled steel coil ring (<NUM>) to form a second profiled steel coil ring (<NUM>), characterised by transferring the second profiled steel coil ring (<NUM>) to a third pre-forming machine wherein a third profile is formed in the second profiled steel coil ring (<NUM>) to form a third profiled steel coil ring, and transferring the third profiled steel coil ring to a final forming machine wherein a final profile is formed in the third profiled steel coil ring to form a final profiled steel coil bearing seal (<NUM>), wherein the first profile formed in the flattened steel coil ring is formed at an angle of about <NUM>°, and
wherein the second profile formed in the first profiled steel coil ring is formed at an angle of about <NUM>°.