Patent Description:
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.

Through use of a bearing seal, the bearing attempts to retain lubricants in the form of oils or grease while also excluding external water and abrasives. The bearing seal is a ring shaped structure that usually includes a resilient seal member.

Patent Document <CIT> describes a method of manufacturing a bearing seal for use in a roller bearing.

Disclosed herein are methods of manufacturing a roller bearing seal case. These manufacturing methods may be used to manufacture roller bearing seal cases for implementation in a variety of roller bearing types. For example, the methods may be used to manufacture a roller bearing seal case for use in a tapered roller bearing seal case on a railway freight car axle or a heavy-duty truck. More generally, the methods may be used to manufacture roller bearing seal cases for implementation in a roller bearing or ball bearing requiring a lubricant.

The methods disclosed herein provide improvements over conventional methods especially in regards to material use. The conventional methods usually involve stamping a round shape out of a metal sheet, resulting in a significant amount of scrap. In contrast, the presently disclosed methods utilize roll-forming to minimize material waste. These roll-forming methods are further adapted to form the roller bearing seal cases with improved roundness and accuracy.

<FIG>, <FIG>, and <FIG> illustrate one tapered roller bearing assembly <NUM> having two exemplary seal cases <NUM> and <NUM> that may be manufactured according to the roll-forming methods disclosed herein. Tapered roller bearing assembly <NUM> is of the type commonly used in railway applications to support a railcar wheel on an axle, and <FIG> and <FIG> show tapered roller bearing assembly <NUM> mounted on a journal <NUM> of an axle of a railcar. <FIG> shows a full section view of tapered roller bearing assembly <NUM> mounted on journal <NUM>, with the section being taken along the rotation axis <NUM> of journal <NUM>. <FIG> is a pictorial section view of tapered roller bearing assembly <NUM>, also with the section being taken along rotation axis <NUM> of journal <NUM>. <FIG> is a close-up of an upper left-hand portion of the full section view of <FIG>. <FIG> are best viewed together in the following description.

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

In some examples not belonging to the invention, tapered roller bearing assembly <NUM> has wear rings <NUM> and <NUM> fitted over journal <NUM> at each end of tapered roller bearing assembly <NUM>. Wear rings <NUM> and <NUM> typically have an inner diameter dimension providing an interference fit with journal <NUM> over at least a portion of their length. Wear rings <NUM> and <NUM> rotate with journal <NUM> as it turns. Wear rings <NUM> and <NUM> protect journal <NUM> against rubbing wear from the tapered roller bearing assembly <NUM> by providing a wear surface.

Although tapered roller bearing assembly <NUM> is pressed onto journal <NUM>, further restraint is generally required against axial loads. Herein, "axial" refers to directions that are generally along rotation axis <NUM>, and "radial" refers to directions that are generally orthogonal to rotation axis <NUM>. To provide the axial restraint, tapered roller bearing assembly <NUM> is captured between a backing ring assembly <NUM> at the inboard end <NUM> of tapered roller bearing assembly <NUM> and a bearing retaining cap <NUM> at the outboard end <NUM> of tapered roller bearing assembly <NUM>.

A shoulder <NUM> of journal <NUM> prohibits axially inward displacement of backing ring assembly <NUM>, such that backing ring assembly <NUM> restrains tapered roller bearing assembly <NUM> against axially inward displacement. At outboard end <NUM> of journal <NUM>, tapered roller bearing assembly <NUM> is captured by 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 journal <NUM>. Bearing retaining cap <NUM> completes the mounting of tapered roller bearing assembly <NUM> onto journal <NUM>, and provides a clamping force to restrain tapered roller bearing assembly <NUM> against axially outward displacement.

Tapered roller bearing assembly <NUM> is preassembled from a number of individual components, including two cylindrical bearing cones <NUM> and <NUM> and a cylindrical bearing cup <NUM>. Bearing cup <NUM> forms radially-inward-directed outer raceways <NUM> and <NUM>. Bearing cones <NUM> and <NUM> have radially-outward-directed inner raceways <NUM> and <NUM>, respectively. A center spacer <NUM> is positioned between bearing cones <NUM> and <NUM> to accurately position and maintain bearing cones <NUM> and <NUM> in place relative to each other and to allow for proper bearing lateral clearance. Outer raceway <NUM> of bearing cup <NUM> cooperates with inner raceway <NUM> of bearing cone <NUM> to capture and support a row of tapered rollers <NUM>. The row of tapered rollers <NUM> encircles journal <NUM>. Similarly, outer raceway <NUM> of bearing cup <NUM> cooperates with inner raceway <NUM> of bearing cone <NUM> to capture and support a row of tapered rollers <NUM>. The row of tapered rollers <NUM> encircles journal <NUM>. In some examples not belonging to the invention, cages <NUM> and <NUM> maintain the circumferential spatial positioning of tapered rollers <NUM> and <NUM> around journal <NUM>.

Bearing seals <NUM> and <NUM> cover the outboard and inboard ends, respectively, of tapered roller bearing assembly <NUM> to minimize (a) lubricant leakage from tapered roller bearing assembly <NUM> and (b) intrusion of contaminants, such as water or abrasives, into tapered roller bearing assembly <NUM>. Bearing seals <NUM> and <NUM> form a dynamic seal between stationary and moving bearing assembly components. Bearing seal <NUM> includes seal case <NUM>, and bearing seal <NUM> includes seal case <NUM>. Each of seal cases <NUM> and <NUM> encircles journal <NUM>, is generally ring-shaped, and is typically made of steel. Bearing seals <NUM> and <NUM> (a) affix to stationary (i.e., non-rotating) side of tapered roller bearing assembly <NUM> (such as bearing cup <NUM>) by interference fit or other method, and (b) are the sealed against wear rings <NUM> and <NUM>, respectively, to seal tapered roller bearing assembly <NUM>. Bearing seals <NUM> and <NUM> may be identical or similar to each other. In one example not belonging to the invention, each of seal case <NUM> and seal case <NUM> includes a first radial edge <NUM> (as shown in <FIG> for seal case <NUM>) that extends radially outward and fits against an inner radial surface <NUM> of bearing cup <NUM>. A second radial edge <NUM> (shown in <FIG> for seal case <NUM>) of each of seal cases <NUM> and <NUM> extends radially inward and has a resilient seal <NUM> attached thereto. Resilient seal <NUM> contacts outer radial surface <NUM> of the associated wear ring (wear ring <NUM> for seal case <NUM>, and wear ring <NUM> for seal case <NUM>) and is typically made of a rubber or synthetic flexible material.

<FIG> show seal case <NUM> (or <NUM>) in perspective view and schematic cross-sectional view, respectively. The cross section in <FIG> coincides with rotation axis <NUM>. <FIG> are best viewed together in the following description. Seal case <NUM> is formed from a single piece of material, for example steel. Seal case <NUM> includes radial section <NUM> and a side section <NUM> connected therewith. At its radially inward perimeter, radial section <NUM> terminates in radial edge <NUM> defining an aperture <NUM>. Side section <NUM> includes an axial section <NUM>, a radial section <NUM>, and an axial section <NUM>. Herein, a "radial section" refers to a section that extends toward or away from rotation axis <NUM>, and an "axial section" refers to a section that extends along rotation axis <NUM>. Aperture <NUM> has diameter <NUM>. Axial section <NUM> has inner diameter <NUM>, and axial section <NUM> has inner diameter <NUM>. Inner diameter <NUM> is greater than diameter <NUM>, and inner diameter <NUM> is greater than inner diameter <NUM>. Without departing from the scope hereof, seal case <NUM> may further include radial edge <NUM> (<FIG>) at the end of axial section <NUM> furthest from radial section <NUM>.

<FIG> illustrate another seal case <NUM> that may be manufactured according to the roll-forming methods disclosed herein. <FIG> show seal case <NUM> in perspective view and cross-sectional view, respectively. The cross section in <FIG> coincides with rotation axis <NUM>. <FIG> are best viewed together in the following description. Seal case <NUM> may be used to seal tapered roller bearing assembly <NUM> in place of each of seal cases <NUM> and <NUM>.

Seal case <NUM> is formed from a single piece of material, for example steel, and includes a radial section <NUM> and an axial section <NUM>. Radial section <NUM> is similar to radial section <NUM>. The inner perimeter of radial section <NUM> defines an aperture <NUM> having diameter <NUM>. Axial section <NUM> is a simplified version of side section <NUM>. Axial section <NUM> has inner diameter <NUM> which is greater than diameter <NUM>.

Although <FIG> show radial section <NUM> as being perpendicular to rotation axis <NUM>, radial section <NUM> may be at an oblique angle to rotation axis <NUM> without departing from the scope hereof. Likewise, axial section <NUM> may be at an oblique angle to rotation axis <NUM> without departing from the scope hereof.

<FIG> illustrate a seal case <NUM> having three steps in diameter. Seal case <NUM> may be manufactured according to the roll-forming methods disclosed herein. <FIG> show seal case <NUM> in perspective view and cross-sectional view, respectively. The cross section in <FIG> coincides with rotation axis <NUM>. <FIG> are best viewed together in the following description. Seal case <NUM> may be used to seal tapered roller bearing assembly <NUM> in place of each of seal cases <NUM> and <NUM>.

Seal case <NUM> includes a radial section <NUM> and a stepped-diameter section <NUM>. Seal case <NUM> is similar to seal case <NUM> except for replacing radial section <NUM> with radial section <NUM> and replacing axial section <NUM> with section <NUM>. Radial section <NUM> is similar to radial section <NUM> and defines an aperture <NUM> with diameter <NUM>. Section <NUM> includes an axial section <NUM>, a radial section <NUM>, an axial section <NUM>, a radial section <NUM>, and an axial section <NUM>. Axial section <NUM> has inner diameter <NUM> which is greater than diameter <NUM>. Axial section <NUM> has inner diameter <NUM> which is greater than inner diameter <NUM>. Axial section <NUM> has inner diameter <NUM> which is greater than inner diameter <NUM>. Axial section <NUM> may be used to affix seal case <NUM> in a bearing cup, such as bearing cup <NUM> (<FIG>), in a manner similar to that of radial edge <NUM>.

Although <FIG> show radial sections <NUM>, <NUM>, and <NUM> as being perpendicular to rotation axis <NUM>, one or more of radial sections <NUM>, <NUM>, and <NUM> may be at an oblique angle to rotation axis <NUM> without departing from the scope hereof. Likewise, one or more of axial sections <NUM>, <NUM>, <NUM> may be at an oblique angle to rotation axis <NUM> without departing from the scope hereof.

<FIG> illustrate a conventional drawing process <NUM> for manufacturing a seal case <NUM> similar to seal case <NUM>,<NUM>. <FIG> are best viewed together in the following description. Drawing process <NUM> stamps the 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>. Drawing process <NUM> manufactures seal case <NUM> through a progressive die stamping operation. These progressive operations are generally shown in <FIG>. A first stamping operation forms a pre-form seal case <NUM> having a centrally located component <NUM>. In a second stamping operation, component <NUM> is restruck, and pre-form seal case <NUM> is given an initial start of its final geometry to form a seal case <NUM> having a centrally located component <NUM>. In a third stamping operation, component <NUM> is cut and pressed back into seal case <NUM>, and seal case <NUM> is coined to its final form. In a final operation, component <NUM> is removed, leaving behind a seal case <NUM>.

The ultimate amount of waste product (see <FIG>) from this convention drawing process is center component <NUM> and a leftover portion <NUM> of coil of steel <NUM>.

<FIG> illustrates one roll-forming method <NUM> for manufacturing a seal case, which includes an intermediate step of improving roundness of the workpiece. Method <NUM> is, for example, used to manufacture any one of seal cases <NUM>, <NUM>, and <NUM>. Method <NUM> applies roll-forming to better utilize the input material, so as to reduce waste as compared to drawing process <NUM>. Method <NUM> may form the seal case from metal, such as steel.

In one embodiment, method <NUM> initiates with receiving a cylindrical ring and applying a roll-forming step <NUM> to the cylindrical ring. In another embodiment, method <NUM> first forms the cylindrical ring in a step <NUM> before proceeding to roll-forming step <NUM>. Step <NUM> may form the cylindrical ring without generating waste. In one embodiment, step <NUM> includes a step <NUM> of roll-forming the cylindrical ring from a rectangular strip, for example a flat rectangular strip of steel. The strip is roll-formed to join opposite ends of the strip, so as to form a cylindrical ring. The ends may be joined by welding. In another embodiment, step <NUM> includes a step <NUM> of cutting the cylindrical ring from a tube. Both step <NUM> and step <NUM> may be performed without generating waste.

In a step <NUM>, method <NUM> roll-forms a first profiled ring from a cylindrical ring. The first profiled ring has an axial section extending along the cylinder axis of the cylindrical ring and a radial section extending from the first section inward toward the cylinder axis. Step <NUM> may include a step <NUM> of forming the radial section by bending a portion of the cylindrical ring toward the cylinder axis.

<FIG> illustrates an example of step <NUM> implementing step <NUM> to roll-form a profiled ring <NUM> from a cylindrical ring <NUM>. In this example of step <NUM>, cylindrical ring <NUM> is placed in a roll-forming station <NUM>. Roll-forming station <NUM> is configured to roll-form profiled ring <NUM> from cylindrical ring <NUM>. Roll-forming station <NUM> includes a die <NUM> mounted on a base <NUM>. Roll-forming station <NUM> further includes rollers <NUM> and <NUM>. Rollers <NUM> are orthogonal to base <NUM>, and roller <NUM> is parallel to base <NUM>. Rollers <NUM> and <NUM> cooperate with die <NUM> to bend a portion <NUM> of cylindrical ring <NUM> inward toward the cylinder axis <NUM> of cylindrical ring <NUM>, to form a radial section <NUM> from portion <NUM> while a remaining portion <NUM> of cylindrical ring <NUM> is maintained as an axial section <NUM>, thereby forming profiled ring <NUM>. Radial section <NUM> defines an aperture <NUM> having diameter <NUM>. Axial section <NUM> has an inner diameter <NUM> which is greater than diameter <NUM>.

Without departing from the scope hereof, roller <NUM> may be at an oblique angle to base <NUM> to form radial section <NUM> at an oblique angle to cylinder axis <NUM>.

Referring again to <FIG>, method <NUM> further includes a step <NUM> applying radially outward pressure to the axial section of the first profiled ring, formed in step <NUM>, to improve roundness of the axial section. Step <NUM> may additionally serve to adjust the sizing of the axial section to more accurately achieve a desired size thereof.

<FIG> illustrates one exemplary effect of the radially outward pressure applied in step <NUM>. In this example, an axial section (for example, axial section <NUM>) has an initially non-cylindrical cross section <NUM>. Radially outward pressure <NUM> corrects cross section <NUM> to achieve, or at least more closely approximate, a desired circular cross section <NUM>. Radially outward pressure <NUM> is, for example, produced by an expandable die placed inside axial section <NUM>.

<FIG> illustrates another exemplary effect of the radially outward pressure <NUM> applied in step <NUM>. In this example, an axial section (for example, axial section <NUM>) has a non-uniform profile <NUM> along cylinder axis <NUM>. For example, the corner <NUM> where a radial section (for example, radial section <NUM>) meets an axial section (for example, axial section <NUM>) may be less square than desired and/or have a varying degree of deviations from roundness. In the example depicted in <FIG>, non-uniform profile <NUM> has less defined corners. However, non-uniform profile <NUM> may instead be bulging outwards, as indicated in the right-hand side of <FIG> by profile <NUM>'. Radially outward pressure <NUM> corrects profile <NUM> to achieve, or at least more closely approximate, a desired profile <NUM>, such as a profile <NUM> with a more square corner between the radial and axial sections.

In another example, step <NUM> achieves a combination of the effects shown in <FIG>. It is understood that radially outward pressure <NUM> may further modify the sizing of the axial section (for example, axial section <NUM>) by expanding the diameter of the axial section.

Referring again to <FIG>, step <NUM> may include steps <NUM> and <NUM>. Step <NUM> positions a segmented die in a region enclosed by the axial section of the profiled ring formed in step <NUM>. Step <NUM> inserts a tapered key into the segmented die to press segments of the segmented die radially outward toward the axial section.

<FIG> illustrate, in perspective view and cross-sectional view, respectively, one example of step <NUM> that implements steps <NUM> and <NUM> to improve the roundness of profiled ring <NUM>. The example shown in <FIG> may further modify the sizing of profiled ring <NUM> as discussed above in reference to <FIG>. <FIG> are best viewed together in the following description.

In the example of <FIG>, profiled ring <NUM> is placed over a segmented die having a plurality of die segments <NUM>. For clarity of illustration, not all die segments <NUM> are labeled in <FIG>. A tapered key <NUM> is positioned in a central aperture of segments <NUM>. Tapered key <NUM> includes a tapered, cannulated core <NUM>, a driver <NUM>, and a receptacle <NUM>. The interface between core <NUM> and die segments <NUM> is tapered, with the diameter of core <NUM> increasing in the direction away from receptacle <NUM>. The axial position of receptacle <NUM>, along cylinder axis <NUM>, is fixed relative to die segments <NUM>. When driver <NUM> is moved downward further into receptacle <NUM> (for example by threading driver <NUM> further into receptacle <NUM>), core <NUM> is forced downward as well. This positions a greater-diameter portion of core <NUM> at the interface with die segments <NUM>, thereby forcing die segments <NUM> radially outward such that die segments <NUM> apply radially outward pressure <NUM> on a radially-inward-facing surface <NUM> of axial section <NUM>.

Although not shown in <FIG>, die segments <NUM> may be resting on a base to which receptacle <NUM> is directly or indirectly fastened. Without departing from the scope hereof, die segments <NUM> and tapered key <NUM> may be oriented such that driver <NUM> enters core <NUM> from the side of die segments <NUM> that is away from radial section <NUM>, as opposed to the side of die segments <NUM> that is adjacent to radial section <NUM> (as shown in <FIG>).

Referring again to <FIG>, method <NUM> further includes a step <NUM> of roll-forming a second profiled ring from the first profiled ring of step <NUM>. Step <NUM> is performed after step <NUM> and benefits from the improved roundness (and optionally improved sizing accuracy) achieved in step <NUM>. The improved roundness (and optionally sizing accuracy) improves the accuracy of the roll-forming of step <NUM> by providing a better fit between the first profiled ring and elements used to roll-form the first profile ring.

In an embodiment, step <NUM> includes steps <NUM> and <NUM>. Step <NUM> places the first profiled ring in a roll-forming die such that a first portion of the first section contacts a first inward cylindrical surface of the roll-forming die. The improved roundness of the first section improves concentricity of the first profiled ring with the roll-forming die.

For each of at least one second portion of the axial section (e.g., axial section <NUM>) away from the first portion of the axial section, step <NUM> rolls a roller against an inward facing surface of the second portion of the first section, to press the second portion of the first section against a greater-diameter inward facing cylindrical surface of the roll-forming die, so as to expand the diameter of the second portion. For each such second portion of the axial section, step <NUM> introduces a step in the diameter of the axial section. When configured to introduce more than one step in the diameter of the axial section, different rollers may be applied simultaneously or sequentially to introduce the respective steps simultaneously or sequentially.

<FIG> illustrate one example of step <NUM>, implementing steps <NUM> and <NUM>, that introduces a single step in the diameter of axial section <NUM> of profiled ring <NUM> to produce a second profiled ring <NUM>. <FIG> provides a perspective view of this example of step <NUM>. <FIG> provide a cross-sectional view, respectively, of step <NUM> of this example. <FIG> provides a cross-sectional view of step <NUM> of this example. <FIG> are best viewed together in the following description.

In this example of step <NUM>, profiled ring <NUM> is placed in a die <NUM>. More specifically, radial section <NUM> rests on a shelf <NUM> of die <NUM> with a portion of axial section <NUM>, closest to radial section <NUM> fitted against a radially-inward-facing surface <NUM> of die <NUM>. The improved roundness (and optionally sizing accuracy) of axial section <NUM> achieved in step <NUM> provides for improved concentricity of axial section <NUM> and radially-inward-facing surface <NUM>, which in turn improves the accuracy of roll-forming operations performed in step <NUM>. The improved roundness (and optionally sizing accuracy) may also generally improve the tightness of the fit between axial section <NUM> and radially-inward-facing surface <NUM>. Radially-inward-facing surface <NUM> is adjacent shelf <NUM>. At a greater distance from shelf <NUM>, die <NUM> forms another shelf <NUM> that transitions radially-inward-facing surface <NUM> to another radially-inward-facing surface <NUM>. The diameter <NUM> of radially-inward-facing surface <NUM> is greater than the diameter <NUM> of radially-inward-facing surface <NUM>.

Next, in this example and as shown in <FIG> and <FIG>, a roller <NUM> is rolled against a portion <NUM> of the radially-inward-facing surface of axial section <NUM> to press the associated portion of axial section <NUM> against radially-inward-facing surface <NUM> of die <NUM>. This results in the modification of axial section <NUM> to a stepped diameter profile including an axial section <NUM>, adjacent radial section <NUM>, an axial section <NUM> further from radial section <NUM>, and a radial section <NUM> providing the transition between axial section <NUM> and axial section <NUM>. Axial section <NUM> has inner diameter <NUM>, and axial section <NUM> has an inner diameter <NUM> that is greater than inner diameter <NUM>.

<FIG> illustrates a modification to the <FIG> example of step <NUM>, which forms two steps in the diameter of the axial section of profiled ring <NUM> to produce a second profiled ring <NUM>. In this example of <FIG>, profiled ring <NUM> is placed in a die <NUM>. Die <NUM> is similar to die <NUM>, except for having an additional step in diameter. As compared to die <NUM>, die <NUM> replaces radially-inward-facing surface <NUM> with a first radially-inward-facing surface <NUM>, adjacent to shelf <NUM>, a second inward radially-inward-facing surface <NUM>, and a shelf <NUM> connecting radially-inward-facing surfaces <NUM> and <NUM>.

In the example of <FIG>, roller <NUM> presses against a portion <NUM> of the radially-inward-facing surface of axial section <NUM> to press the associated portion of axial section <NUM> against radially-inward-facing surface <NUM>. A second roller <NUM> presses a portion <NUM> of the radially-inward-facing surface of axial section <NUM> to press the associated portion of axial section <NUM> against radially-inward-facing surface <NUM>. This results in the modification of axial section <NUM> to a double-stepped diameter profile that, as compared to second profiled ring <NUM> forms an additional radially protruding bead <NUM>.

Referring again to <FIG>, in an embodiment, step <NUM> includes a step <NUM> of forming a radially protruding bead configured to lock the second profiled ring into a bearing cup. For example, step <NUM> forms radially protruding bead <NUM>.

<FIG> illustrates one exemplary method <NUM> for making a cylindrical ring by cutting a cylindrical tube. Method <NUM> avoids the production of waste products associated with drawing process <NUM>. The embodiment of step <NUM> of method <NUM> that includes step <NUM> may implement method <NUM>.

In a step <NUM>, method <NUM> cuts a cylindrical tube to form a plurality of cylindrical rings. In one example of step <NUM>, a metal cylinder is sliced to produce a plurality of cylindrical rings <NUM>. The metal cylinder may be made of steel. Step <NUM> may utilize cutting methods known in the art.

Step <NUM> may be preceded by a step <NUM> of making the cylindrical tube. In one embodiment, step <NUM> includes a step <NUM> of extruding the cylindrical tube. In another embodiment, step <NUM> includes a step <NUM> of roll-forming the cylindrical tube. For example, step <NUM> roll-forms a metal sheet into a tube. Step <NUM> may include a step <NUM> of welding the seam where two opposite edges of the sheet join each other to form the cylindrical tube.

Embodiments of method <NUM> that include step <NUM> may further include a step <NUM> performed after step <NUM> and prior to step <NUM>. Step <NUM> removes the weld bead formed in step <NUM>, for example according to a process known in the art. Alternatively, embodiments of method <NUM> that include step <NUM> may include a step <NUM>, performed after step <NUM>, of removing the weld bead from each individual cylindrical ring formed in step <NUM>. Step <NUM> may utilize a weld bead removal process known in the art.

After completion of method <NUM>, each cylindrical ring produced thereby may be processed by steps <NUM>, <NUM>, and <NUM> of method <NUM> to form a seal case.

<FIG> illustrates one example of step <NUM> of method <NUM>. In this example, a cylindrical tube <NUM> is cut along dicing lines <NUM> to form a plurality of cylindrical rings <NUM>, each having an axial extent <NUM>. It is understood that manufacturing tolerances may cause some variation in axial extent <NUM>, both azimuthal variation of axial extent <NUM> for an individual cylindrical ring <NUM> and different axial extents <NUM> for different cylindrical rings <NUM>.

<FIG> illustrates one example of step <NUM> implementing step <NUM>. In this example, a sheet <NUM> (for example a flat metal sheet) is roll-formed to join two opposite edges <NUM> and <NUM> to form a cylindrical tube <NUM>. The joint between edges <NUM> and <NUM> is welded, resulting in a weld bead <NUM>.

<FIG> illustrates one roll-forming method <NUM> for manufacturing a seal case, which includes an step of trimming an radial section to refine an aperture. Method <NUM> is, for example, used to manufacture any one of seal cases <NUM>, <NUM>, and <NUM>. Method <NUM> applies roll-forming to cylindrical ring better utilize the input material, so as to reduce waste as compared to drawing process <NUM>. Method <NUM> may form the seal case from cylindrical metal ring, such as a cylindrical steel ring. The trimming step reduces potential inaccuracies in the size of the central aperture of the seal case. For example, when roll-forming a seal case from cylindrical ring <NUM> in the absence of the trimming step, manufacturing tolerances for axial extent <NUM> may transfer to diameter <NUM> of aperture <NUM>. The trimming step may remove the sensitivity to such tolerances.

In a step <NUM>, method <NUM> roll-forms a profiled ring from a cylindrical ring. The profiled ring has at least an axial section extending along the cylinder axis of the cylindrical ring and a radial section extending from the axial section inward toward the cylinder axis. The radial section defines a first aperture about the cylindrical axis. Step <NUM> may include a step <NUM> of bending a portion of the cylindrical ring toward the cylinder axis to form the radial section. In an embodiment, step <NUM> includes a step <NUM> of forming the first aperture of the profiled ring with location and geometry at least partly determined by the axial extent of the cylindrical ring and/or wall thickness of the cylindrical ring. Herein, the wall thickness refers to the thickness of the wall of the cylindrical ring in the dimension orthogonal to the cylinder axis. The first aperture may also be influenced by additional tolerance introduced by the roll-forming process of step <NUM>. In one embodiment, step <NUM> implements steps <NUM>, <NUM>, and <NUM> of method <NUM>. In another embodiment, step <NUM> implements steps <NUM> and <NUM>, but not step <NUM>.

Step <NUM> may be preceded by a step <NUM> of receiving a cylindrical ring formed by cutting a cylindrical tube. In one example, step <NUM> receives a cylindrical ring formed by method <NUM>. The axial extent of this cylindrical ring may be subject to manufacturing tolerances.

<FIG> illustrate one example of at least a portion of step <NUM>. <FIG> provides a perspective view of this example and <FIG> shows associated cross sections <NUM> indicated in <FIG> are best viewed together in the following description. In this example, step <NUM> receives cylindrical ring <NUM> having axial extent <NUM>, wall thickness <NUM>, and diameter <NUM>. Step <NUM> forms profiled ring <NUM> with aperture <NUM> having diameter <NUM>. The value of diameter <NUM> is at least partly defined by axial extent <NUM> and wall thickness <NUM>. For example, a greater value of axial extent <NUM> leads to a greater value of the radial extent <NUM> of radial section <NUM>, and a greater value of wall thickness <NUM> may also lead to a greater value of radial extent <NUM>. Any excess in radial extent <NUM> corresponds to a reduced value of diameter <NUM>, and any lack of radial extent <NUM> corresponds to an increased value of diameter <NUM>.

It is understood that step <NUM> may include additional and/or more complex roll-forming operations than that shown in <FIG>. For example, step <NUM> may form one or more steps in the diameter of axial section of the profiled ring.

Referring again to <FIG>, method <NUM> further includes a step <NUM> of trimming the radial section to expand the first aperture to a second aperture having location and geometry according to predefined design parameters. In an embodiment, step <NUM> includes a step <NUM> of forming the second aperture with location and geometry insensitive to the axial extent and the wall thickness of the cylindrical ring, and optionally also insensitive to additional tolerance introduced by the roll-forming in step <NUM>. In embodiments of method <NUM> including step <NUM>, step <NUM> may include a step <NUM> of forming the second aperture with location and geometry insensitive to the axial extent tolerance associated with cutting the cylindrical ring from cylindrical tube. In particular, method <NUM> may accept cylindrical rings with less accurate axial extent, since step <NUM> removes (or at least significantly reduces) the sensitivity to the axial extent tolerance. Thus, these embodiments of method <NUM> relax the requirements to the accuracy with which the cylindrical rings are cut from the cylindrical tube. In an embodiment, step <NUM> includes a step <NUM> of stamping out the second aperture. Step <NUM> may further include a step <NUM> of imprinting a marking on the radial section of the profiled ring. Step <NUM> is performed in the same stamping operation that stamps out the second aperture.

<FIG> illustrate one example of step <NUM> implementing step <NUM>. <FIG> shows a series of cross-sectional views of the workpiece of step <NUM>. <FIG> shows a perspective view of the final product of this example. <FIG> are best viewed together in the following description.

In the example shown in <FIG>, step <NUM> receives profiled ring <NUM> having an initial aperture <NUM> with diameter <NUM>. A stamp <NUM> having diameter <NUM> punches out some of radial section <NUM> of profiled ring <NUM> to form a modified profiled ring <NUM> with a modified radial section <NUM> that defines a larger aperture <NUM> characterized by a diameter <NUM>.

Without departing from the scope hereof, aperture <NUM> may deviate from perfect circularity, and aperture <NUM> may have improved circularity over aperture <NUM>.

Claim 1:
A roll-forming manufacturing method (<NUM>) of a roller bearing seal case, comprising:
roll-forming (<NUM>), from a cylindrical ring (<NUM>), a first profiled ring (<NUM>) having a first section (<NUM>) extending along a cylinder axis (<NUM>) of the cylindrical ring and a second section (<NUM>) extending from the first section inward toward the cylinder axis; characterized in that the method further comprises:
applying (<NUM>) outward pressure (<NUM>) to the first section at a corner where it meets the second section, the outward pressure being directed away from the cylinder axis, to round the first section; and
roll-forming (<NUM>), after said applying outward pressure to the first section, a second profiled ring from the first profiled ring.