Flangeless retrofittable severe duty seal for a shaft

A unitary sleeve lip seal can be used to provide permanently lubricated sealed bearings in severe service conditions such as the track pins of track-driven vehicles and agricultural equipment. The seal has a labyrinthine exclusion path and multiple dust lips contacting the sleeve in addition to the main sealing lip. A garter spring encircling the main sealing lip may enable the seal to operate at moderately elevated pressures. The sleeve has a radial flange at the outermost end. Elastomeric lips extend between the sleeve flange and a faceplate that terminates the outside end of the seal housing. The seal is packed with water-resistant grease and can, when installed in association with grease-packed bearings can create a permanently lubricated bearing/shaft assembly that requires no re-greasing. Resilient coatings both protect the sleeve and case and also improve leak resistance, especially when the seal is retrofitted onto shafts that have been damaged. The design provides a seal having performance that is comparable to that of dual cone face seals at a much lower cost and in a much smaller assembly. Seals made according to this design can easily be made in standard sizes that can serve as direct replacements for previously available seals.

TECHNICAL FIELD
 The present disclosure is related to the field of seals for sealing rotary
 shafts, generally. The methods and apparatus are particularly related to
 the field of unitary combination lip and sleeve seals. More specifically,
 this is an improved seal adapted for use in severe duty applications
 including construction equipment, agricultural machinery, track driven
 vehicles, and other applications where oil or grease must be held in
 contact with rotary shaft and bearing assemblies. This seal and other
 seals of this type must also operate as excluder seals to keep lubricated
 surfaces free from corrosives, acids, other chemicals, dirt, mud, dust,
 abrasives, water and other contaminants. Even more particularly, this seal
 incorporates design features that enhance performance (compared to usual
 original equipment seals) when installed on shafts that have been slightly
 damaged by normal wear. Most specifically, this seal can be used as a pin
 or roller seal for track driven vehicles.
 BACKGROUND AND SUMMARY
 The present seal structure yields a very important benefit that has eluded
 other persons skilled in the art. It can be retrofitted to existing, worn
 machinery to enhance the protection of costly lubricated machine
 components. This seal can replace existing seals, and the performance of
 this seal exceeds that of all other standard-sized, commercially
 available, conventional, lip and sleeve type seals. The only commercially
 available type of seal with performance comparable to this embodiment is
 the dual cone face seal. It is known by those in the art that dual cone
 face shields have disadvantages that significantly restrict their use. The
 seal disclosed here overcomes the two major inherent disadvantages of dual
 cone face seals--large size and high cost.
 Conventional unitized lip and sleeve seals are much smaller than dual cone
 face seals. Since this seal can be installed as a direct replacement for
 ordinary seals, it can be specified and used without making any
 modifications to the design of an existing machine. The shaft, the bore,
 and the housing in which the seal operates are identical whether the
 present seal or conventional seals are used. Wherever dual cone face seals
 are desired, the machine must have been originally designed specifically
 for their use because they are much larger than ordinary seals. They are
 simply too big to fit all of the machine locations where their superior
 performance could justify the significant added cost.
 However, the availability of a seal having the superior performance
 characteristics of an embodiment according to the present disclosure in a
 package the size of ordinary seals gives additional freedom to designers
 of heavy machinery and severe duty assemblies. Design possibilities made
 available by this new seal include increasing the size of wear surfaces
 without the necessity of increasing the overall size of the assembly to
 enhance the useful life of machines and their component parts. Another
 design possibility is to expand the utility of existing designs by making
 them better adapted for broader ranges of service.
 The cost of making a seal according to the present disclosure is only a
 fraction of the cost of making a dual cone face seal. Cost savings can be
 substantial because the manufacturing cost for a dual cone face seal is
 currently between twenty and ninety times the cost of a conventional seal.
 A preferred embodiment of the present disclosure is expected to be two to
 three times the cost of a conventional seal. In some applications, such as
 crawler vehicles, a single machine will typically require 40 to 60 roller
 seals, each of which is subjected to extremes of heat, cold, moisture,
 dust, abrasives, acids and alkalis. In addition, the loads imposed on
 track vehicle components fluctuate extremely. For example, a roller may be
 subject to little load while the vehicle operates on a flat, level
 surface; but when tracks advance to a raised obstruction such as a rock,
 each roller that moves over the rock may be sequentially required to
 support almost the entire weight of the vehicle. The constantly
 fluctuating loads exacerbate the effects of any deviation from component
 design tolerances.
 The most important benefit of the seal now disclosed is that it can create
 permanently lubricated shaft and bearing assemblies that can withstand
 severe use. This seal may enable equipment manufacturers to improve the
 performance of their machinery by reducing maintenance requirements. It is
 believed that existing vehicles and other machines can be retrofitted
 advantageously by replacing the original re-greasable seals with this new
 permanently lubricated seal. It is to be understood, however, that the
 present seal can be used to seal in either oil or grease and to exclude
 all environmental contaminants that do not attack the materials from which
 the seal is manufactured.
 It is an object of the invention to accomplish the foregoing and to teach
 the structure of an externally flangeless retrofittable severe duty seal
 for a shaft.
 It is a further object of this disclosure to show an embodiment useful for
 sealing bearings in shaft-mounted rotary rollers used in track-driven
 vehicles.
 Another object is to provide an embodiment that may be useful in any
 application where a shaft and shaft bearing or bushing surfaces may be
 exposed to mud, dust, abrasives, cement, submersion, abrasive liquids or
 other substances that could damage relative rotary mechanical components.
 Another object hereof is to disclose a seal that lasts longer than
 previously known low cost seals adapted for severe duty applications.
 Another object of the present disclosure is to make essentially all of the
 important benefits of a dual cone face seal available at a much lower
 cost.
 Yet another object hereof is to make essentially all of the important
 benefits of a dual cone face seal available in a physically smaller
 assembly.
 It is an object to make essentially all of the important benefits of a dual
 cone face seal available in an assembly having the same physical
 dimensions as a conventional single lip or double lip seal.
 Another object hereof is to provide an embodiment that can function as an
 excluder seal, as a grease seal, as an oil seal, and as a seal for other
 liquids at low and moderate pressures.
 Another object of this disclosure is to provide a seal having a
 shaft-contacting sleeve that enables the seal to be installed on and to
 operate reliably with shafts having imperfections such as those ordinarily
 caused by wear and use.
 Another specific object is to provide a unitary seal structure that both
 improves reliability, and makes seal installation easier compared to
 installation of seals that are composed of two or more separable parts.
 A further object is to provide a seal with sealing elements that include: a
 main sealing lip with a garter spring that biases the main sealing lip
 against the outside of the sleeve, at least one dust lip that contacts the
 sleeve, at least one dust lip that contacts the inner surface of the
 housing, at least one face dust lip that contacts the inner surface of the
 faceplate, and an elastomeric, shaft-contacting faceplate ring.
 These and further objects of the apparatus taught in accordance with this
 specification, the claims, and the appended drawing figures are set forth
 below.
 DISCLOSURE OF THE INVENTION
 The present disclosure Shows an externally flangeless, unitized,
 retrofittable, radial lip seal for a paired shaft and bore assembly
 rotatable with respect to one another having a sleeve that may be disposed
 coaxially on the shaft. The term externally flangeless refers to seals in
 which the flanges are inside the seal, i.e., inside the seal case.
 Consequently, externally flangeless seals disclosed in the specification
 have sleeve and case flanges that are internal flanges, i.e., flanges that
 are inside the seal case. The sleeve has an inner end, (oil side) that
 would normally be in contact with the grease, oil, or other fluid to be
 contained within a housing, an outer end (dirt side) opposite, a bore that
 has an elastomeric coating, and a sleeve flange extending radially outward
 from the outer end of the sleeve and generally perpendicular to the sleeve
 axis. The sleeve flange is terminated with an outer edge. One or more
 circular elastomeric faceplate-contacting lips extend coaxially opposite
 the oil side from the sleeve flange outer face.
 A circular elastomeric perimeter lip extends radially and outwardly from
 the outer edge of the sleeve flange to contact a generally cylindrical
 hollow seal case adapted for fitting into a bore, such as a bore that is
 formed through a roller end plate, the wall of a housing, or other
 securement.
 The case is formed from a generally cylindrical case body having an outside
 surface, or outside diameter, that may be disposed within a bore and in
 contact with the wall of the bore. An elastomeric coating may be affixed
 to the outside of the case body. By coating the outside of the metal case
 body with an elastomeric coating or layer, it is possible for the seal to
 securely fit a bore that has become slightly damaged through use.
 The inner surface of the case is smoothly finished in the region close to
 the outer end to properly adapt it for maintaining continuous operating
 contact with the perimeter lip of the sleeve flange. The case has an
 inner, fluid-contacting, end opposite the outer end; the inner end is
 sometimes referred to as the "oil side." A case flange extends radially
 inward from, and generally perpendicular to, the outside end of the case.
 Various processes such as drawing, coining, or forging may be employed to
 make the case body and the case flange as a unit from a single piece of
 cylindrical tubular material. An equivalent case body and case flange
 assembly may also be formed by joining separate component parts.
 Two case inner flanges are located between the outer end and the fluid end
 of the case. The case inner flanges extend radially inward from the case
 to support two axially spaced-apart seal elements, each of which may be
 fitted with a garter spring.
 The case inner flanges extend radially inwardly from, and generally
 perpendicular to, the longitudinal axis of the inside of the case. When
 formed of two additional pieces of material, preferably coated with
 elastomer, the case has double thickness of material. The case
 reinforcement provided by the double layer of metal makes allows the use
 of a slightly thinner material to form the case body than would be
 necessary if the case material was a single thickness. Other methods of
 construction may be adopted, however, without departing from the scope of
 the invention disclosed. For example, one or more case inner flanges may
 be inserted into the case sequentially.
 A sleeve-contacting secondary sealing lip may be formed on the radial
 flange of a first, or medial, insert. When the seal is assembled, grease
 such as Esso Beacon 325 or any other high quality, light, stable grease is
 applied to the surfaces of the sleeve and it is placed with the sleeve
 flange proximate the faceplate. The first, or medial insert is then
 greased and placed in the case with the seal lip, which may be fitted with
 a biasing garter spring, contacting the sleeve. Additional excluder, or
 dust, lips may extend from the radial flange of the insert to contact the
 sleeve and/or the sleeve flange.
 A second, or oil side, insert may then be placed into the case with the oil
 side insert flange having a primary oil seal affixed to it and biased
 against the sleeve by a garter spring. One or more excluder lips may also
 be formed as part of the oil side insert to provide additional assurance
 that contaminants will not penetrate and contaminate the lubricant and
 bearing surfaces. It is desirable to fill the void spaces with grease
 during assembly. The grease reduces friction and wear, provides additional
 barriers to dust and other contaminants, and enhances seal performance by
 preserving the resiliency of elastomeric portions.
 When the seal has been packed with grease and assembled, the inner end of
 the case may be crimped over the oil side insert inner end to secure the
 assembly and prevent dis-assembly during installation or use.
 At least one sleeve-contacting, elastomeric, sealing lip extends from each
 case inner flange to operatively contact the outer surface of the sleeve
 at a region near the inner end of the sleeve. The main sealing lips may be
 fitted with a garter spring to enable the assembly to operate at higher
 pressures. Testing has confirmed that the seal disclosed herein can
 operate reliably at a pressure of one atmosphere (15 p.s.i.) with shaft
 speeds of 700 feet per minute.
 The maximum pressure at which this seal, like seals in general, can
 reliably operate decreases with increasing shaft speed. Testing may show
 that operation is satisfactory at pressures of approximately 100 p.s.i. or
 that slight changes could allow the seal to operate in the range of 100
 p.s.i. However, testing at higher pressures and rotational velocities had
 not been concluded before preparation of the present disclosure.
 The primary and the secondary sealing lips extend inwardly, toward the
 inner end and medial region of the sleeve, coaxially with the sleeve. One
 or more dust lips are positioned to extend radially inwardly from the
 medial insert flange into coaxial contact with the sleeve outer surface.
 One of the inwardly oriented dust lips, the mid-sleeve dust lip, may be
 disposed generally between the case inner flange aperture and the sleeve
 outer surface. The optional second sleeve contacting dust lip, the forward
 sleeve dust lip, is disposed generally midway between sleeve flange and
 the medial insert flange. A third dust lip, the medial insert flange dust
 lip, extends axially outwardly from the medial insert flange. The three
 dust lips and the secondary sealing lip are molded at high temperatures in
 one piece using a single mold operation and bonded to the insert with
 suitable bonding agents.
 A resilient layer may cover the outside of the case to improve sealing in
 conditions where soft, damaged, or other less than optimal bore conditions
 exist that would impair reliable sealing with a steel outer case surface.
 It is possible to cover the oil side insert and form the primary seal
 element similarly. In applications that might expose the sealed materials
 to corrosion, it is preferred to cover with resilient rubberized material
 all of the portions of the seal case that are likely to contact the
 corrosive agents.
 The case elastomeric coating is formed with a chamfer to minimize the
 likelihood that the seal will be damaged during installation. One or more
 optional radial case relief channels may be formed in the case elastomeric
 coating. A relief channel may reduce relieves the tendency of the
 elastomeric coating to form a bulge that could cause the seal to become
 unseated and move axially after installation. It is also possible to
 provide radial ribs on the outer surface of the case elastomeric coating
 for the purpose of providing desired installation properties.
 A generally planar circular faceplate has an inside surface, an outside
 surface, and a central aperture slightly larger than the inside diameter
 of the sleeve. The plane of the inner faceplate surface is disposed
 generally parallel to the case skirt and the face of the sleeve flange. An
 elastomeric portion, or faceplate wiper ring, can be attached to the
 faceplate at the central aperture so that the faceplate wiper ring extends
 between the faceplate and the shaft. The faceplate wiper ring has an
 internal diameter that allows it to contact the shaft and thereby exclude
 contaminants from the remainder of the seal and the sealed components.
 The sleeve bore is preferably coated with an elastomeric, or rubberized,
 coating to make it possible to obtain adequate sealing performance when
 the shaft condition is substandard due to wear, eccentricity, or other
 causes. A sleeve radial channel may be formed generally midway between the
 sleeve inner end and the sleeve outer end. The channel relieves shear
 tension that may develop during installation. The result is that it is
 easier to install the sleeve and the potential for damage to the sleeve
 during installation is reduced.
 Chamfers are provided at both the inner end and at the outer end of the
 sleeve bore to reduce the potential for damage to the seal, the shaft, or
 the housing during installation. In addition, the inner end of the case
 outer surface is chamfered to make insertion of the sleeve through the
 housing easier and less likely to damage the dust lips or other
 components.
 The flange peripheral lip and face lips may be formed in the same molding
 operation that is used to mold the sleeve bore elastomeric coating. The
 face lips may be designed with shapes similar to those of the peripheral
 lip and the three dust lips. However, an alternative design for the face
 lips is disclosed herein. The undercut face lips are adapted to provide
 superior performance in severe duty operating conditions. The advantage
 accrues because the undercut lip inside surface responds with increasing
 pressure in response to contact with materials that would penetrate the
 seal. The other lips contact the mating seal surface at distinctly
 different approach angles and with quite different elastomer shapes and
 configurations.
 It is preferred to have the inner side of the faceplate smoothly finished
 to reduce wear on the face lips of the seal. Likewise, the outer surface
 of the sleeve, the sleeve flange inner face, and the perimeter
 lip-contacting medial insert inside cylindrical surface may be finished to
 a condition of low surface roughness to reduce the amount of wear to which
 the various elastomeric excluder and seal lips are subjected. For this
 reason, it is generally preferred to make the sleeve, case, and faceplate
 of metal such as stainless steel, carbon steel, or similar materials. It
 is to be understood, however that the sleeve, case, and faceplate may be
 made from other metals and also from non-metallic materials.
 In seals of this nature, the seals are normally described by reference to
 the cross-sectional configuration. The seal of the present embodiment may
 readily be manufactured in sizes between 0.5 inches and 26 inches with
 other sizes available on request. By way of example only and without any
 limitation on the configuration of embodiments of this disclosure, a
 representative seal may have an inside (shaft) diameter of 31/8", an
 outside (bore) diameter of 41/8", with an overall width of about 1". The
 various dimensions do not scale proportionately. For example, the same
 type of seal may be manufactured for a 61/4" shaft diameter but still have
 an overall width of 1" and be designed to fit into a 73/4" bore. Seals
 adapted to various purposes may vary in width from less than 1/8" to over
 1" but generally have a width between 1/4" and 3/4".
 It is to be understood, as well, that many different formulations of the
 elastomeric, or rubberized, elements may function satisfactorily.
 Viton.RTM., nitrile, carboxylated nitrile, polyacrylate, ACM,
 fluroelastomers, and silicone compounds are known to provide useful
 operational characteristics when adapted for incorporation within the seal
 presently disclosed. Other materials may also be incorporated to confer
 chemical resistance, extreme temperature resistance, expanded operating
 pressure range, wear resistance, or other desired properties to the final
 seal assembly.

DESCRIPTION OF THE PREFERRED EMBODIMENTS
 Referring now to the various figures of the accompanying drawing, FIG. 1
 depicts a cross-sectional profile of an embodiment of the externally
 flangeless retrofittable sever duty seal 20 fitted onto a shaft 21. A
 cylindrical sleeve 22 component is disposed coaxially over, and in contact
 with, the shaft 21 so that when installation is complete, the sleeve 22 is
 affixed to the shaft 21. The sleeve inner end 24 extends into the sealed
 region, normally a housing or containment for oil or grease used to
 lubricate gears, bearings, or other moving parts.
 To simplify nomenclature in this specification, the side or end or surface
 of a component that is oriented toward the lubricants, lubricated
 components, or other media from which it is desired to exclude dust,
 water, mud, and other environmental contaminants may be referred to using
 the terms "inner," "inward," "inside," and similar terms. The words
 "outer," "outward," "outside" and similar terms may be used to refer to a
 side, end, or surface of a component that is oriented away from the sealed
 region, toward the exterior of a housing, or toward the unsealed overall
 environment into which a shaft extends.
 Between the sleeve inner end 24 and the sleeve outer end 26, the sleeve
 bore 28 may optionally be coated with an elastomeric coating 30. The
 optional sleeve bore elastomeric coating 30 is desirable because it may
 prevent leakage from between the seal 20 and the shaft 21 even when the
 shaft is worn, damaged, or otherwise imperfect.
 A sleeve flange 32 extends radially outwardly from the sleeve outer end 26
 and has a sleeve flange outer edge 34 at its outer periphery. At least
 one, and preferably two, face lips 36 extend coaxially outwardly from the
 sleeve flange 32 outer face 38 and a perimeter lip 40 extends radially
 outwardly from the sleeve flange outer edge 34. The sleeve bore
 elastomeric coating 30, the face lips 36, and the perimeter lip 40 may be
 integrally formed and bonded to the sleeve 22 in a single injection
 molding operation.
 A seal case 42 is disposed coaxially outside the sleeve 22. The seal case
 42 has a generally cylindrical case body 44 designed so that the case
 outside surface 45 can fit into and seal against a bore in a housing or
 flange through which the shaft 21 to be sealed extends. It is preferred to
 enclose the case outside surface 45 with an optional case elastomeric
 coating 46. The seal 20 is less likely to leak when installed in a damaged
 bore if the optional case elastomeric coating 46 is provided. The case
 body 44 has a case inner surface 47 that may be smoothly finished in the
 region near the case outer end 48 if the perimeter lip 40 will contact it.
 The case inner end 49 is axially opposite the case outer end 48. An insert
 50 (if there is more than one insert, a "first" or "medial" insert 50) may
 be introduced within the case 42 through the case inner end 49. The medial
 insert 50 has an outer surface 51, an insert inner end 52 and an outer end
 53 that are securely disposed against the case inner surface 47 and the
 case outer end 48.
 A first insert flange 54 extends radially inwardly from the case body 44
 toward the sleeve 22. The first insert flange 54 has a circular central
 aperture through which the shaft 21 and sleeve 22 fit. Positioning the
 insert 50 within the case body 44 reinforces the structure with a double
 layer of the material from which the case body 44 is made. In addition,
 the insert flange 54 stiffens the case body 44.
 It may be desirable to coat the case 44 contacting insert 50 surface with
 an elastomer coating 55 opposite the first insert inside cylindrical
 surface 56. The elastomer coating 55 may extend to the insert flange bore
 57 and may also be used to integrally form the seal lip 58 and excluder
 lips.
 The secondary sealing lip 58 (in configurations having multiple inserts,
 otherwise it is the primary sealing lip) attaches to the case medial, or
 first, insert flange 54 and extends both axially inwardly and radially
 inward from the first insert flange 54. The sealing lip 58 may be biased
 radially inwardly by a garter spring 59.
 A optional second, or oil side, cylindrical insert 60 may also be fitted
 within the case body 44. An oil side insert outer surface 61 can be
 disposed against the case body inner surface 47 with the second insert
 inner 62 end proximate the case inner end 49 and the second insert outer
 end 63 adjacent the first insert inner end 52. An oil side flange 64
 extends radially inwardly toward the sleeve 22 and has affixed to it the
 elastomer coating 65 that also coats the oil side flange bore 67. One or
 more oil side excluder lips 69 and the primary seal 70 may be formed
 integrally from the elastomeric coating 65 applied to the insert 60.
 The primary seal lip 70 contacts the sleeve outer surface 72 to form the
 sealing element by which the contents (generally fluids) of the sealed
 volume are prevented from transferring to the outside of the assembly. A
 biasing spring 74 may urge the main seal lip 70 against the sleeve outer
 surface 72.
 Likewise, the secondary sealing lip 58 is optionally biased against the
 sleeve outer surface 72 by a garter spring 59. The sleeve outer surface 72
 may be polished or otherwise finished to retard wear of the elastomeric
 elements. Additional contaminant excluding elements are situated axially
 outwardly from either or both the primary seal lip 70 and or the secondary
 sealing lip 58. These additional dust lips (also called excluder lips) may
 extend between the case body 44 or from the inserts 5060 disposed within
 the case body 44 and brought into contact with the sleeve outer surface 72
 or the inner side of the sleeve flange 32.
 A mid-sleeve dust lip 75 may be located generally between the first insert
 flange 54 and the sleeve outer surface 72. A forward sleeve dust lip 76
 may be disposed against the sleeve outer surface 72 at a location close to
 the sleeve flange 32. A sleeve flange dust lip 77 may extend from the
 first insert flange 54 to contact the sleeve flange 32. The case
 elastomeric coating 46, the main sealing lip 70, the mid-sleeve dust lip
 75, the forward sleeve dust lip 76 and the sleeve flange dust lip 77 may
 be integrally formed and bonded to the first insert 50 in a single
 injection molding operation.
 On the inner end of the case body 44, the case elastomeric coating 46 is
 finished with a case elastomeric coating chamfer 78 to make it easier to
 install the seal 20 without distortion or damage. A case outside diameter
 relief channel 79 is formed in the case elastomeric coating 46. The
 optional relief channel 79 relieves axial shear stresses from the case
 elastomeric coating 46 that may be induced by the process of installing
 the seal 20 into a bore. Application of grease 80 to the shaft 21 or bore
 during installation is generally not recommended.
 Three main sub-assemblies, the sleeve 22, the case 42, and the faceplate 81
 are interconnected to form a complete seal 20. These three sub-assemblies
 are normally made primarily of steel or another metal that is shaped,
 worked, and polished using conventional metalworking techniques and
 commercially available equipment. It may be advantageous to smooth the
 metal surfaces that are contacted by the various elastomeric components to
 obtain a metal finish having low surface roughness. Carefully shaped and
 molded elastomeric compounds are bonded to the metal components in the
 configurations shown in the accompanying drawing. It is possible to form
 the elastomeric components and attach them to the metal structures in a
 variety of ways; however, injection molding is believed preferable for
 these purposes.
 Final assembly of the seal 20 is performed by carrying out four additional
 steps. First, water-resistant grease 80, such as Esso Beacon 325.TM. is
 packed to fill all of the voids between the lips and between the inserts
 5060. Second, the sleeve 22 is inserted into the seal case 42 so that the
 sleeve flange dust lip 77 contacts the sleeve flange 32 and the perimeter
 lip 40 contacts the perimeter lip-contacting case inner surface 47 or an
 equivalent cylindrical inner surface. Third, grease 80 is packed into the
 interstices between the individual face lips 36 and also between the
 perimeter lip 40 and the outermost of the face lips 36. Fourth, the
 inserts 5060 are secured within the seal case 42 by crimping or other
 means to complete the assembly and unitizing process.
 After the sleeve 22 is fitted within the seal case 42, the faceplate inner
 side 82 contacts the face lips 36 and the sleeve flange inner face 84 is
 brought into contact with the sleeve flange dust lip 77.
 An optional elastomeric faceplate wiper ring 86 can be bonded to a central
 aperture in the faceplate 81 coaxial with, and through which, the shaft 21
 extends.
 A sleeve radial channel 90 is preferably formed within the sleeve bore
 elastomeric coating 30 to relieve shear as the sleeve 20 is fitted to a
 shaft. The sleeve 22 is finished with a sleeve outer end chamfer 92 and a
 sleeve inner end chamfer 94 to reduce the potential for tearing of the
 sleeve bore elastomeric coating 30 and for distortion of the sleeve 22
 during installation of the seal 20. Likewise, the seal case 42 may be
 fitted with a case inner end chamfer 96 to reduce damage to the case
 elastomeric coating 46 when the case is fitted with elastomeric coating
 and to prevent case distortion in embodiments without case elastomeric
 coating 46. A case crimp 97 is used to prevent the inserts 5060 from
 becoming dislodged during installation and operation.
 It is believed preferable for the face lips 36 to be sharply angled
 radially inwardly with an acute point at the innermost portion of each of
 the face lips 36. In order to form a lip having such a shape, it may be
 necessary to include a face lip undercut angle 98 that is less than 90
 degrees to obtain the desired performance characteristics. The face lips
 36 may be formed having a generally triangular cross-section.
 FIG. 2 shows an embodiment wherein the seal 20 is fitted with a single
 insert 50 and sealing lip 70. Although there may be some loss of
 ruggedness in this configuration, the countervailing considerations are
 that the seal can have a narrower profile, lower cost, lighter weight,
 lower rolling resistance, and still has excellent performance and
 durability.
 FIG. 3 shows an alternative embodiment of the seal 20 wherein a triple lip
 main seal 100 is used in place of the single lip primary seal 70 with
 garter spring 74. Otherwise, the configuration is similar to that depicted
 in FIG. 1. The triple lip seal 100 may allow a narrower profile, but will
 often require a seal configuration that has more radial space (i.e.
 increased height).
 FIG. 4 shows a representative application in which the seal 20 may be
 installed, specifically, a roller assembly 110. The roller 110 is retained
 on a stub shaft 112 secured with any known stub fastener assembly 113, for
 example screw fasteners that retain a plate. The roller 110 may be
 comprised of an end cap 114, opposite a seal cover 116 held in place by
 cover fasteners 118 such as cap screws that engage, either directly or
 indirectly, a roller load-contacting peripheral surface 120 situated
 between the end cap 114 and the seal cover 116. By way of illustration
 only, and not by way of limitation, a stub shaft 112 may have a shoulder
 122 and the end cap 114 may have a shoulder 123 also between which against
 which a distal roller bearing 124 may fit when affixed to the shaft 112.
 Adjacent the roller bearing 124 and opposite the shaft shoulder 122, a
 retainer 126 may be installed on the shaft 112 to prevent the roller 110
 from detaching.
 A coaxial spacer 128 can be fitted between the distal roller bearing 124
 and a medial roller bearing 130. A cover shoulder 132 urges the medial
 roller bearing 130 against the spacer 128. The seal 20 is fitted into the
 cover bore 134 to prevent loss of lubricant and to exclude contaminants
 from the bearings 124130.
 INDUSTRIAL APPLICABILITY
 From the foregoing, it may be readily understood by those skilled in the
 art that the embodiments disclosed are applicable to industry and
 mechanical power transmission generally, and to machinery and vehicles
 that are operated in severe environments, particularly. Incorporation of
 the present embodiment into new and existing equipment is expected to
 substantially reduce the maintenance requirements of many types of
 construction and agricultural equipment.
 Changes and modifications in the specifically described embodiments can be
 carried out without departing from the scope of the invention which is
 intended to be limited only by the scope of the appended claims.

REFERENCES TO DRAWING NUMBERS
 20 Flangeless Retrofittable Severe 56 (medial or first) insert
 Duty Seal for a Shaft side cylindrical surface
 21 shaft (reduced scale) 57 (medial or first) insert
 flange bore
 22 sleeve 58 secondary seal lip
 24 sleeve inner end (oil end) 59 secondary seal garter spring
 26 sleeve outer end (air end) 60 oil side cylindrical insert
 28 sleeve bore 61 oil side insert outer surface
 30 sleeve bore elastomeric coating 62 oil side insert inner end
 32 sleeve flange 63 oil side insert outer end
 34 sleeve flange outer edge 64 oil side flange
 36 face lips 65 oil side elastomer coating
 38 sleeve flange outer face 67 oil side flange bore
 40 perimeter lip 69 primary seal excluder lip
 42 seal case 70 primary seal lip
 44 case, body 72 sleeve outer surface
 45 case outside surface 74 primary seal garter spring
 46 case elastomeric coating 75 mid-sleeve dust lip
 47 case body inner surface 76 forward sleeve dust lip
 48 case outer end 77 sleeve flange dust lip
 49 case inner end 78 case elastomeric coating
 50 insert or medial (first) insert chamfer
 51 (medial or first) insert outer 79 case outside diameter
 surface optional relief channel
 52 (medial or first) insert inner end 80 grease
 53 (medial or first) insert outer end 81 faceplate
 54 (medial or first) insert flange 82 faceplate inner side
 55 (medial or first) insert elastomer 84 sleeve flange inner face
 portion 86 elastomeric faceplate wiper
 ring
 94 sleeve inner end chamfer 90 sleeve radial channel
 96 case inner end chamfer 92 sleeve outer end chamfer
 97 case crimp
 98 face lip undercut angle
 100 alternative, triple lip, main seal
 110 roller assembly
 112 stub shaft
 113 stub shaft fastener assy.
 114 end cap
 116 seal cover
 118 cover fasteners
 120 roller load-contacting peripheral
 surface
 122 shaft shoulder
 123 end cap shoulder
 124 distal roller bearing
 126 retainer
 128 spacer
 130 medial roller bearing
 132 cover shoulder
 134 cover bore