AU756059B2 - Outer seal assembly and roller bearing seal assembly - Google Patents

Description

WO 00/40487 PCT/AU99/011 48 -1- TITLE: "OUTER SEAL ASSEMBLY AND ROLLER BEARING SEAL

ASSEMBLY"

FIELD OF THE INVENTION This invention relates to conveyer rollers and in particular the outer seal assembly of the roller bearing seal assembly which is utilised to support each end of a roller shell from the shaft.

BACKGROUND OF THE INVENTION It has been found over a period of time that the service failure of conveyer rollers will often be as a result of bearing failure which is as a result of the ingress of dirt and/or water into the bearing past the seals which are associated with the bearing in the roller bearing seal assembly. Most conveyor assemblies are used in conveying bulk material and are installed in bulk handling facilities in which a dust laden atmosphere and/or a wet environments is the norm and in which high pressure water is often used to wash down the conveyer assembly for maintenance cleaning. As a result the roller bearing assembly must be able to withstand such harsh conditions.

This invention relates to the outer seal assembly of a bearing seal assembly of an idler roller where the outer seal assembly is supported from the shaft supporting the roller and serves to prevent the entry of foreign matter into the bearing, from the interior of the roller shell. Relevant prior art to the present invention includes the following patent specifications: AU-B- 55759/80; AU-B- 27410/84; 21089/88; and AU-B-40450/85; AU-B-85487/82; AU-B-36874/84; AU- B-40198/85; AU-B-31577/77; US3,799,634; US3,957,147; US3,144,280; US4,632,404; US4,699,895; US4,789,252; US4,799,808; US5,149,207; US5,487,611; US5,890,812; US4,208,057; US4,252,329; US5,015,001; US5,201,528; US5,292,199; US5,028,054; 1. NOV. 2002 16:34 WRAY AND ASSOCIATES NO. 112 P. -2- DISCLOSURE OF THE INVENTION Accordingly, the invention resides in a roller bearing seal assembly to be located in the passage in the end of a roller shell to support the roller shell from the shaft, said roller bearing seal assembly comprising an outer seal assembly and a bearing, wherein the outer seal assembly comprises, a first annular member adapted to be non-rotatably supported on the shaft and which is located outermost, a second annular member adapted to be supported from the shell located closely adjacent the first annular member, the radial extent of the members being such that they overlap, wherein the outer seal assembly further S 10 comprises a resilient flexible sealing element supported on the first or second annular member and being in slidable contact with the opposed face of the other annular member.

According to a preferred feature of the invention the roller bearing seal assembly further comprises an inner seal, said inner seal being intended to be located 15 adjacent the innermost face of the bearing, said inner seal adapted to be nonrotatably supported from the shaft proximate the inner edge of the annular flange of the roller shell, the diameter of the outer radial face of the inner seal being such that the outer radial face is in closely spaced relation to the inner edge when the inner seal is in position in a roller shell, the axial dimension of the outer 20 radial face of the inner seal being such that the outer radial face extends to either side of the inner edge when the inner seal is in position in a roller shell and the outer radial face is formed at the inner end of the inner seal relative to the roller shell with a first lip which is spaced inwardly relative to the roller shell, from the inner edge when the inner seal is in position in a roller shell.

According to a preferred feature of the invention the sealing element defines a channel shaped surface between the first and second annular members which is directed radially outwardly.

WO 00/40487 PCT/AU99/01148 -3- According to a preferred feature of the invention the outer edge of the sealing element comprises a first lip seal which is radially innermost and which is in sliding contact with the other annular member, the sealing element further comprising a second lip seal which is radially outermost and is in sliding contact with the other annular member and is deflected radially outwardly. According to a preferred feature of the invention the first lip seal is in light sliding contact with the other annular member. According to an alternative preferred feature of the invention the outer edge of the sealing element is formed as a flange which extends radially outward from the sealing element, said flange being in sliding sealing contact with the other annular member.

According to a preferred feature of the invention the sealing element is supported on the second annular member. According to a preferred feature of the invention the second annular member has a flange at its inner edge.

According to one embodiment the flange at least partially supports the sealing element.

According to a preferred feature of the invention the sealing element is formed of formed from an elastomeric material or a material having elastomeric like properties.

According to a preferred feature of the invention the second annular member is adapted to be sealingly engaged with the shell. According to a preferred feature of the invention the sealing engagement is provided by a resilient sealing medium supported from the second annular member. According to one embodiment the sealinn mredium is hnnr,'r to the outer radial face of the- 0 e e v I-L L11- %JU LUlI €;IU IC II V;Ib I LIIV second annular member. According to a preferred feature of the invention the sealing medium is formed from an elastomeric material or a material having elastomeric like properties. According to a preferred feature of the invention the second annular member is formed as a composite member comprising a rigid annulus and a moulding supported by the rigid annulus. According to one embodiment the sealing medium is formed as an integral part of the moulding.

WO 00/40487 PCT/AU99/01148 -4- According to a further feature of the embodiment the sealing element is formed as an integral part of the moulding. According to a preferred feature of the embodiment the moulding is formed from an elastomeric material or a material having elastomeric like properties.

According to a preferred feature of the invention the outer seal assembly further comprises a rigid shaft seal adapted to be non-rotatably supported on the shaft and located between the first annular member and the bearing; wherein the shaft seal comprises a first annular flange extending radially outwardly from the shaft into the space between the second annular member and the bearing, said shaft seal having an outer radial surface which is closely adjacent the inner radial face of the second annular member, said shaft seal being configured to frictionally engage the first annular member. According to a preferred feature of the invention the shaft seal is formed of a substantially rigid plastics material.

According to a preferred feature of the invention the shaft seal supports the first annular member from the shaft. According to one embodiment the outer radial surface comprises a second annular flange extending radially outwardly from the shaft such that its outer periphery is located closely adjacent the inner radial face of the second annular member. According to another embodiment the outer radial surface of the shaft seal and inner radial face of the second annular member have an axial extent.

According to a preferred feature of the invention the roller bearing seal assembly further comprises an inner seal, said inner seal being intended to be located adjacent the innermost face of the bearing, said inner seal adapted to be nonrIa-.kI..,y supported from th L Z ft- proximate the inner edge of the annular flange of the roller shell, the diameter of the outer radial face of the inner seal being such that the outer radial face is in closely spaced relation to the inner edge when the inner seal is in position in a roller shell, the axial dimension of the outer radial face of the inner seal being such that the outer radial face extends to either side of the inner edge when the inner seal is in position in a roller shell and the outer radial face is formed at the inner end of the inner seal relative to WO 00/40487 PCT/AU99/01148 the roller shell with a first lip which is spaced inwardly relative to the roller shell, from the inner edge when the inner seal is in position in a roller shell. According to one embodiment the outer radial face is substantially parallel to the central axis. According to an alternative embodiment the outer radial face is convergent in the direction of the first lip. According to another embodiment the outer end of the outer radial face relative to the roller shell, is formed with a second lip which is spaced outwardly, relative to the roller shell, from the inner edge when the inner seal is in position in the roller shell whereby the outer radial face has a generally channel shaped configuration defined by the first and second lip and the portion of the outer radial face between the first and second lips. According to a preferred feature of the invention the second lip is dimensioned to be in sliding sealing relationship with the outer radial portion of the bearing when the inner seal is in position in a roller shell. According to a preferred feature of the invention the portion of the outer radial face between the first and second lips is convergent in the direction from the second lip to the first lip. According to a preferred feature of the invention the first lip is formed with a sharp outer edge.

According to a preferred feature of the invention the first lip is spaced outwardly from the inner edge a sufficient distance such that vertical plane containing the lower most extent of the first lip is spaced inwardly, relative to the roller shell, from the vertical plane containing the lowermost extent of the rotational path of the inner edge when the inner seal is in position in a roller shell and the roller shell is in use.

Accordingly the invention also resides in a roller shell having a roller bearing assembly of the form described above to support the roller shell from the shaft.

The invention will be more fully understood in the light of the following description of several specific embodiments.

BRIEF DESCRIPTION OF THE DRAWING The description is made with reference to the accompanying drawings of which: W000/40487 PCT/AU99/01148 -6- Figure 1 is a part sectional elevation of a roller shell supported upon a shaft by a roller bearing seal assembly according to the first embodiment; and Figure 2 is a part sectional elevation of a roller shell supported upon a shaft by a roller bearing seal assembly according to the second embodiment.

DESCRIPTION OF SPECIFIC EMBODIMENTS OF THE INVENTION The first embodiment comprises a roller bearing seal assembly which can be utilised to support a roller shell 11 from a shaft 13. The roller shell 11 is of a generally conventional form and is formed at each end with a central recessed portion which is formed by an inner flange 12 which is substantially parallel with the outer periphery of the roller shell and which terminates at its innermost end with a radial flange 14 which is inclined inwardly with respect to the radial axis.

The roller bearing seal assembly comprises an outer seal assembly 15, a bearing 17 and an inner seal 19.

The outer seal assembly 15 comprises a first annular member or deflection seal 21 which is formed of sheet metal and is located axially outermost. The deflection seal 21 is adapted to be frictionally fixed to the shaft 13 and in use is retained in position by a retainer circlip 23. The outer portion 25 of the deflection seal is formed such that it is inclined from the radial axis in the direction of the bearing 17.

The outer seal assembly further comprises a second annular member or intermediate seal 27 which is formed of sheet metal and is frictionally received within the flange 12 which defines the annular recess in the end face of the roller shell. To ensure a tight sealing engagement between the intermediate seal 27 and the roller shell 11, the outer radial face 33 of the intermediate seal is coated with a resiliently compressible sealing medium 35. The sealing medium is sealingly engaged with the innermost radial face of the flange 12 of the roller WO 00/40487 PCT/AU99/01148 -7shell. The sealing medium comprises an elastomeric material or a material having elastomeric-like properties and is moulded onto the outer radial face 33.

The use of the sealing medium 35 between the intermediate seal 27 and the roller shell presents a significant improvement over the use of direct frictional engagement of the intermediate seal with the roller shell. Such advantages include: 1. the resilient compressible nature of the sealing medium ensures that it effectively seals the junction between the roller shell and the intermediate seal to prevent the passage of water past the sealing medium; 2. the resilient compressible nature of the sealing medium enables the sealing medium to accommodate for any lack of circularity between the intermediate seal and the roller shell whilst maintaining a sealing engagement there between and as a result serves to keep the outer seal centralised in the roller shell by accommodating for deformation in the flange 12 of the roller shell and/or the intermediate seal; 3. in the case of direct metal to metal engagement between the intermediate seal and the roller shell which has been the practice in the past, any plastic deformation of the intermediate seal and/or the flange may result on the loosening of the outer seal in the roller sheII and a reduction in the sea! formred betAIen the roller shell and the intermediate seal whereas the use of the sealing medium serves to accommodate for any such deformation without a significant reduction in the sealing action or the frictional engagement with the roller shell; WO 00/40487 PCT/AU99/01148 -8- 4. the resilient compressible nature of the sealing medium means that the degree of tolerance in the formation of the sealing medium is not as great as that required with direct metal to metal contact between the intermediate seal and the roller shell and as a result the sealing medium may have a greater diameter than the internal diameter of the radial flange which can serve to increase the sealing and retention properties of the sealing medium; and the coefficient of sliding friction between the sealing medium and the flange 12 is much greater than can be achieved by direct metal to metal contact between the intermediate seal and the roller shell which serves to ensure that the outer seal is retained in the roller shell and is able to withstand axial forces which may be exerted on the outer seal.

The inner radial edge of the intermediate seal 27 is provided with an axially directed flange 31 which is directed axially in the direction of the deflection seal 21. To further enhance the sealing action of the outer seal assembly the axially directed flange 31 of the intermediate seal 27 supports a sealing element 39 which extends axially from the intermediate seal 27 in the direction of the deflection seal 21 to be in a sliding and sealing engagement with the inner face of the deflection seal 21. The sealing element 39 is formed of an elastomeric material or a material having elastomeric-like properties and is bonded to the intermediate seal 27. The outer axial edge of the sealing element which is in sliding contact with the deflection seal 21 is formed as a double lip seal having a first lip seal 41i which is located radially innermost and which is intended to be in light sliding engagement with the inner face of the deflection seal 21. The second lip seal 43 is located radially outermost and has a length such that on engagement with the deflection seal 21, its outer edge is deflected radially outwardly to form a gutter or channel between the deflection seal 21 and the intermediate seal 27.

WO 00/40487 PCT/AU99/01148 -9- The sealing element 39 provides a seal between the deflection seal 21 and the intermediate seal 27 as a result of it providing a barrier between the two elements. In addition the sealing element 39 provides a gutter or channel between the deflection seal and intermediate seal which will direct any water incident upon the sealing element away from the sealing interengagement between the second lip seal 43 and the deflection seal 21. As a result when the sealing element 39 is stationary the water will be caused to flow downwardly over the sealing element and out of the space between the deflection seal 21 and the intermediate seal 27. On rotation of the sealing element 39 as a result of rotation of the roller shell 11 and thus the intermediate seal 27 any water collecting in that gutter or channel to be centrifugally ejected from the space between the deflection seal 21 and the intermediate seal 27. Furthermore in the event of the sealing element being subjected to increased fluid pressure the sealing action between the second lip seal 43 and the inner face of the deflection seal 21 will increase to resist the entry of fluid past the sealing element 32. A further advantage of the sealing element 39 is that in use the centrifugal force which is exerted on the outer lip seal 43 of the sealing element 39 with rotation of the roller will cause the lip to be deflected outwardly in such a way as to reduce the sealing pressure between the outer lip seal 43 and the deflection seal 10 which therefore reduces the seal drag. In addition, when no pressure is being applied externally, any excess grease which is accommodated within the seal can purge past the sealing element.

The outer seal assembly 15 further comprises a shaft seal 29 which is frictionally received on the shaft 13 and is located between the deflection seal 21 and the bearing 17. The shaft seal is formed of a suitable rigid hard plastics material.

The shaft seal comprises a bush-like body which is received on the shaft and an integrally formed first radial flange 31 which extends into the space defined between the intermediate seal 27 and the bearing 17. The outer axial end of the shaft seal is formed with a rebate 32 which will frictionally receive the axially innermost edge of the deflection seal 21 between the shaft 13 and the shaft seal 29. In this regard the axially innermost edge of the deflection seal is formed with WO 00/40487 PCT/AU99/01148 an inwardly directed flange 34 which has in internal diameter corresponding to the external diameter of the shaft and an external diameter corresponding to the internal diameter of the rebate 32 in order that the deflection seal is frictionally engaged with both the shaft 13 and the shaft seal 29.

In addition, the shaft seal 29 is formed with a second radial flange 30 which is spaced axially outward from the first radial flange 31 and is in opposed relation to the axially directed flange 31 of the intermediate seal 27. The diameter of the second radial flange is such that its outer periphery is in a closely spaced relationship with the inner radial face of the axially directed flange 31. The presence of the second radial flange and its close spacing from the intermediate seal 27 serves to enhance the sealing effectiveness of the roller bearing seal assembly.

As a result of the frictional interengagement between the deflection seal 21 and the shaft seal 29 with the intermediate seal 27 located between them, the outer seal assembly 15 can be assembled as a pre-assembled cartridge which can be applied as a unit to the end of a roller and/or over the shaft. In addition the second radial flange 20 serves to centralise and locate the shaft seal 29 relative to the intermediate seal in the assembly of the outer seal as a pre-assembled cartridge. The close tolerance between the second annular flange 30 and the intermediate seal further serves to keep the intermediate seal 27 centralised in the pre-assembled cartridge which facilitates the location of the outer seal assembly 15 on the shaft and into the recess of the roller shell.

I Ie sealing arraniement provided by"th outer seal assembly 15i suc that will prevent the entry of water past the outer seal assembly. This is effected by the utilisation of the resiliently compressible sealing medium 35 between the intermediate seal 27 and the roller shell 11 in order to effect the interference fit between the intermediate seal 27 and the roller shell 11. The sealing arrangement is further enhanced by utilisation of the sealing element 39 which not only provides a barrier between the deflection seal 21 and the intermediate WO 00/40487 PCT/AU99/01148 11 seal 27 but also serves to provide a gutter or channel between the deflection seal and intermediate seal which will divert any water away from the sealing engagement between the sealing element and the deflection seal. In addition on rotation of the sealing element as a result of rotation of the roller shell 11 and thus the intermediate seal 27, the water collecting in that gutter will be centrifugally ejected through the space provided between the outer lip 25 of the deflection seal 21 and the intermediate seal 27. In addition the sealing action of the outer seal assembly is enhanced by the second flange of the shaft seal and its closely spaced relationship with the intermediate seal.

The outer seal assembly 15 of the first embodiment provides a pre-assembled cartridge which when installed in a roller shell and on a shaft has improved sealing properties over the prior art.

The roller bearing seal assembly according to the first embodiment further comprises the rear seal 19 which comprises an inner radial portion 45 which is frictionally received over the shaft 13. On application of the rear seal to the shaft 13 and to the roller shell 11 the axially outermost face of the inner radial portion (relative to the roller shell) bears against inner axial face of the bearing 17. The rear seal further comprises an outer radial portion 47 which extends radially outwardly from the inner portion 14 and has an outer profile which is of a channel shaped configuration which is defined by a first radial lip 49 which is remote from the bearing 17 and a second radial lip 51 which is proximate the bearing 17. In addition, the proximate radial lip 51 has a greater radial extent than the remote radial lip 49 while the outer axial face of the outer portion 47 between the radial lips 49 and 51 is inclined in the direction of the shaft 13 from the proximate radial lip 51 to the remote radial lip 49. In mounting the rear seal to the shaft 13 and the roller shell the radial lips 49 and 51 are located to opposite sides of the inner radial flange 14 of the bearing shell 11. The channel or gutter which is provided at the outer radial extent of the rear seal 19 provides a labyrinth which serves to resist the ingress of any water into the region of the WO 00/40487 PCT/AU99/01148 -12bearing from within the body of the shell 11 both when the roller is stationary and when it is rotating.

The remote radial lip 49 is configured to provide a sharp outer edge. The purpose of the sharp edge is to inhibit the collection of water droplets at the edge and to promote the shedding of water from the rear seal 19. In addition the remote radial lip 49 is spaced sufficiently from the radial flange 14 of the roller shell such that even when the central longitudinal axis of the roller shell is inclined upwardly the outer edge is located outward of the adjacent edge of the radial flange 14. Therefore when water is shed from the radial lip it will fall clear of the inner edge of the flange 14.

It is a further feature of the embodiment that the roller shell 11 is provided with a breather aperture 55 on at least one end face which serves to allow for the passage of air into and out of the shell cavity to accommodate for pressure variations within the body of the roller shell. The purpose of the breather aperture is to ensure that there is a substantial equalisation of pressure between the interior of the shell and the environment and to ensure that any air flow that is induced as a result of an inequality between the interior and exterior is not required to pass through the roller bearing seal assembly. The breather aperture 55 is closed by a plug 57 which is formed of a rigid pervious material which is such that it will permit the passage of air through the breather aperture but will resist the passage of water molecules water in a liquid or gaseous form) through the breather aperture 55. A suitable form of material which can be used in the plug can comprise a sintered glass or like ceramic material. Alternatively the material can comprise a plastics material. According to one example of material the pore size is of the order of 3 micron. As a result of the presence of the plug the flow of air into the roller shell will not result in water being drawn into the shell when the shell is in wet environment. In addition the selective filtering of water molecules from the air as it flows into the roller shell will reduce the likelihood of water collecting in the shell as a result of condensation.

WO 00/40487 PCT/AU99/01148 -13- The second embodiment as shown at Figure 2 comprises a roller bearing seal assembly which can be utilised to support a roller shell 111 from a shaft 113.

The roller shell 111 is of a generally conventional form and is formed at each end with a central recessed portion which is formed by an inner flange 112 which is substantially parallel with the outer periphery of the roller shell and which terminates at its innermost end with a radial flange 114 which is inclined inwardly with respect to the radial axis. The roller bearing seal assembly comprises an outer seal assembly 115, a bearing 117 and an inner seal 119.

The outer seal assembly 115 comprises a first annular member or deflection seal 121 which is formed of sheet metal and is located axially outermost. The deflection seal 121 is adapted to be frictionally fixed to the shaft 113 through the shaft seal 129 in a manner which will be described later. In use the deflection seal and shaft seal 129 is retained in position by a retainer circlip 123. The outer portion 125 of the deflection seal is formed such that it is inclined from the radial axis in the direction of the bearing 117.

The outer seal assembly further comprises a second annular member or intermediate seal 127 which is formed as a single element and is a composite element comprising a sheet metal annulus 126 which supports a moulding 128 formed of an elastomeric material or a material having elastomeric-like properties. The sheet metal annulus is formed at its outer edge is formed with a flange 133 which in use is to be directed towards the bearing 117. The moulding 128 is received over the outer face of the annulus. In addition the moulding extends over the radial outermost surface of the flange 133 to define a first sealing element 135 which is sealingly and frictionally received within the flange 112 which defines the annular recess in the end face of the roller shell. The resilient compressible nature of the moulding 128 ensures a tight sealing engagement between the flange 112 of the roller and the first sealing element 135 of the intermediate seal 127.

WO 00/40487 PCT/AU99/01148 -14- The use of the first sealing element 135 which is an integral part of the moulding between the intermediate seal 127 and the flange of the roller shell presents a significant improvement over the use of direct frictional engagement of a metal intermediate seal with the roller shell. Such advantages include: 1. the resilient compressible nature of the moulding ensures that the first sealing element 135 effectively seals the junction between the roller shell and the intermediate seal to prevent the passage of water past the sealing medium; 2. the resilient compressible nature of the first sealing element 135 enables the first sealing element to accommodate for any lack of circularity between the intermediate seal and the roller shell whilst maintaining a sealing engagement there between and as a result serves to keep the outer seal centralised in the roller shell by accommodating for deformation in the flange 112 of the roller shell and/or the intermediate seal; 3. in the case of direct metal to metal engagement between the intermediate seal and the roller shell which has been the practice in the past, any plastic deformation of the intermediate seal and/or the flange may result on the loosening of the outer seal in the roller shell and a reduction in the seal formed between the roller shell and the intermediate seal whereas the use of the first sealing element 135 serves to accommodate for any such deformation without a significant reduction in the sealing action or the frictional engagement with the roller shell; 4. the resilient compressible nature of the first sealing element 135 means that the degree of tolerance in the formation of the first sealing element 135 is not as great as that required with direct metal to metal contact between the intermediate seal and the roller WO 00/40487 PCT/AU99/01148 shell and as a result the first sealing element may have a greater diameter than the internal diameter of the radial flange which can serve to increase the sealing and retention properties of the sealing medium; and 5. the coefficient of sliding friction between the first sealing element 135 and the flange 112 is much greater than can be achieved by direct metal to metal contact between the intermediate seal and the roller shell which serves to ensure that the outer seal is retained in the roller shell and is able to withstand axial forces which may be exerted on the outer seal.

The inner radial edge of the moulding 128 of the intermediate seal 127 is formed with a second sealing element 139 which extends axially from the intermediate seal 127 in the direction of the deflection seal 121 to be in a sliding and sealing engagement with the inner face of the deflection seal 121. The moulding in the region of the inner end of the second sealing element 139 is formed to extend around the inner radial edge of the annulus 126 such that it is fixed to both faces of the annulus 126 and provides an inner radial face 131 which is in opposed relation to the shaft. The outer axial edge of the second sealing element 139 which is in sliding contact with the deflection seal 121 is formed as a flange 143 which extends radially outwardly from the outer edge of the second sealing element 139 to lie parallel to the inner surface of the deflection seal 121 and to be in light sliding engagement with the inner face of the deflection seal 121. As a result of the configuration of the outer edge of the second sealing element 139 a gutter or channel is defined by the second sealing element 139 between the deflection seal 121 and the main body of the intermediate seal 127.

The second sealing element 139 provides a seal between the deflection seal 121 and the intermediate seal 127 as a result of it providing a barrier between the two elements. In addition the second sealing element 139 provides a gutter or channel between the deflection seal and intermediate seal which will direct WO 00/40487 PCT/AU99/01148 -16any water incident upon the second sealing element 139 away from the sealing interengagement between the flange 143 and the deflection seal 121. As a result when the second sealing element 139 is stationary water will be caused to flow away from the sealing interengagement between the flange 143 and the deflection seal 121, downwardly over the second sealing element and out of the space between the deflection seal 121 and the intermediate seal 127. On rotation of the second sealing element 139 as a result of rotation of the roller shell 111 and thus the intermediate seal 127, any water collecting in that gutter or channel will be caused to be to be centrifugally ejected from the space between the deflection seal 121 and the intermediate seal 127. Furthermore in the event of the second sealing element 139 being subjected to increased fluid pressure the sealing action between the flange 143 and the inner face of the deflection seal 121 will increase to resist the entry of fluid past the second sealing element 139. A further advantage of the second sealing element 139 is that in use the centrifugal force which is exerted on the flange 143 of the second sealing element 139 with rotation of the roller will cause the flange to be deflected outwardly in such a way as to reduce the sealing pressure between the flange 143 and the deflection seal 10 which therefore reduces the seal drag. In addition, when no pressure is being applied externally, any excess grease accommodated within the seal can purge past the second sealing element 139.

The outer seal assembly 115 further comprises a shaft seal which is frictionally received on the shaft 113 and is located between the circlip 123 and the bearing 117. The shaft seal is formed of a suitable rigid and hard plastics material. The shaft seal comprises a bush-like body which is received on the shaft and an integrally formed first radial flange 131 which extends into the space defined between the intermediate seal 127 and the bearing 117. The outer axial end of the shaft seal is formed with a rebate 132 on its outer radial face which frictionally receives the axially innermost edge of the deflection seal 121. In this regard the axially innermost edge of the deflection seal is formed with an inwardly directed flange 134 which has in internal diameter corresponding to the WO 00/40487 PCT/AU99/01148 -17external diameter of the rebate 132 in order that the deflection seal is frictionally engaged with the shaft seal.

The mounting of the deflection seal to the shaft 121 via the shaft seal 129 according to the second embodiment serves to maintain the deflection seal out of engagement with the shaft. As a result the shaft is not damaged in the event of the deflection seal undergoing some angular and/or axial movement relative to the shaft due the absence of any metal to metal contact.

In addition, the intermediate portion 130 of the shaft seal 129 between the rebate and the first radial flange 131 has a diameter which is very similar to but less than the internal diameter of the inner radial face 131 of the intermediate seal 127 and is in opposed relation to the inner radial face 131 of the intermediate seal 127. As a result the outer periphery of the intermediate portion is in a closely spaced relationship with the inner radial face 131 of the intermediate seal 127 and that close spaced relation has a significant axial extent corresponding to the length of the inner radial face 131. The close spacing of the intermediate portion from the intermediate seal and the axial extent of that close spacing serves to enhance the sealing effectiveness of the outer seal assembly.

As a result of the frictional interengagement between the deflection seal 121 and the shaft seal 129 with the intermediate seal 127 located between them, the outer seal assembly 115 can be assembled as a pre-assembled cartridge which can be applied as a unit to the end of a roller and/or over the shaft. In addition the intermediate portion 131 of the shaft seal serves to centraiise and locate the shaft seal 129 relative to the intermediate seal 127 in the assembly of the outer seal as a pre assembled cartridge. The close tolerance between the intermediate portion 130 and the inner radial face of the intermediate seal 127 further serves to keep the intermediate seal 127 centralised in the preassembled cartridge which facilitates the location of the outer seal assembly 115 on the shaft and into the recess of the roller shell. Furthermore the inner end of WO 00/40487 PCT/AU99/01148 -18the rebate 132 serves in axially locating the deflection seal on the shaft seal in the correct position in the assembly of the outer seal 115.

The sealing arrangement which is provided by the outer seal assembly 115 of the second embodiment is such that it will prevent the entry of water past the outer seal assembly. This is effected by the utilisation of the resiliently compressible first sealing element 135 between the intermediate seal 127 and the roller shell 111 in order to effect the interference fit and seal between the intermediate seal 127 and the roller shell 111. The sealing arrangement is further enhanced by utilisation of the second sealing element 139 which not only provides a barrier between the deflection seal 121 and the intermediate seal 127 but also serves to provide a gutter or channel between the deflection seal and intermediate seal which will divert any water away from the sealing engagement between the second sealing element 139 and the deflection seal. In addition on rotation of the second sealing element as a result of rotation of the roller shell 111 and thus the intermediate seal 127, the water collecting in that gutter will be centrifugally ejected through the space provided between the outer lip 125 of the deflection seal 121 and the intermediate seal 127. In addition the sealing action of the outer seal assembly is enhanced by the close spaced relationship between the intermediate portion of the shaft seal and the inner radial face of the intermediate seal.

The outer seal assembly 115 of the second embodiment provides a preassembled cartridge which when installed in a roller shell and on a shaft has improved sealing properties over the prior art.

The roller bearing seal assembly according to the first embodiment further comprises the rear seal 119 which comprises an inner radial portion 145 which is frictionally received over the shaft 113. On application of the rear seal to the shaft 113 and to the roller shell 111 the outermost axial face of the inner portion (relative to the roller shell) bears against inner axial face of the bearing 117. The rear seal further comprises an outer radial portion 147 which extends radially WO 00/40487 PCT/AU99/01148 -19outwardly from the inner radial portion 145 and has an outer diameter such that its external radial surface is closely proximate the inner radial edge of the radial flange 114 of the roller shell. The inner edge of the outer radial portion (relative to the roller shell) is formed with a radial lip 149 which extends radially outwardly from the surface of the outer radial portion 147. In mounting the rear seal to the shaft 113 and the roller shell the radial lip 149 is located to innermost (relative to the roller shell) from radial flange 114 of the bearing shell 111. The close spacing of the outer radial portion 147 from the inner edge of the flange 114 of the roller provides a barrier which serves to resist the ingress of any water into the region of the bearing from within the body of the shell 111 both when the roller is stationary and when it is rotating.

In addition the radial lip 149 is configured to provide a sharp outer edge. The purpose of the sharp edge is to inhibit the collection of water droplets at the edge and to promote the shedding of water from the rear seal 119. In addition when the rear seal is in position the radial lip 149 is spaced sufficiently from the radial flange 114 of the roller shell such that even when the central longitudinal axis of the roller shell is inclined upwardly the outer edge is located outward of the adjacent edge of the radial flange 114. Therefore when water is shed from the radial lip it will fall clear of the inner edge of the flange 114.

It is a further feature of the embodiment that the roller shell 111 is provided with a breather aperture 155 at its end face which serves to allow for the passage of air into and out of the shell cavity to accommodate for pressure and temperature variations within the body of the roller shell as a result. The purpose of the breather aperture is to ensure that there is a substantial equalization of pressure between the interior of the shell and the environment and to ensure that any air flow that is induced as a result of an inequality between the interior and exterior is not required to pass through the roller bearing seal assembly. The breather aperture 155 is closed by a plug 157 which is formed of a rigid pervious material which is such that it will permit the passage of air through the breather aperture 155 but will resist the passage of water molecules water in a liquid or WO 00/40487 PCT/AU99/01148 gaseous form) through the breather aperture 155. A suitable form of material which can be used in the plug can comprise a sintered glass or like ceramic material. Alternatively the material can comprise a plastics material. According to one example of material the pore size is of the order of 3 micron. As a result of the presence of the plug the flow of air into the roller shell as a result of a reduction in pressure within the shell will not result in water being drawn into the shell when the shell is in wet environment. In addition the selective filtering of water molecules from the air as it flows into the roller shell will reduce the likelihood of water collecting in the shell as a result of condensation.

According to an alternative embodiment of the invention the breather aperture of each of the above embodiments is closed by a plate rather than a plug. The plate is fixed to the external face of the shell to overlie the breather aperture where the plate is formed of a rigid pervious material which is such that it will permit the passage of air through the breather aperture but will resist the passage of water molecules water in a liquid or gaseous form) through the breather aperture.

It is a characteristic of the roller bearing seal according to the each of embodiments that the seal assembly the outer seal and rear seal) and the breather aperture closed by a plug or plate as described above are able to significantly resist the passage of water into an out of the body of the shell through the seal assembly even when subjected to relatively high pressure water wash down. In this regard an example of a roller bearing seal according to the second embodiment was applied to each end of a roller shell which incorporated a ubreatherL aperture having a plug according to the second embodiment and the roller shell was applied over a shaft. The complete assembly was then fully immersed in water for a period of time. At the conclusion of the period no water had entered the roller shell.

Furthermore, the compact nature of the outer seal assembly enables the location at which the shaft 13 is supported from a suitable support to be closer to the WO00/40487 PCT/AU99/01148 -21bearing 17 than has been the case with previous embodiments. This reduction in spacing serves to reduce the bending moment between the mounting of the roller shaft to the support and the bearing. This has in turn enabled a reduction in the shaft size and allows for the utilisation of a constant diameter shaft rather than a stepped shaft.

Throughout the specification, unless the context requires otherwise, the word "comprise" or variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated integer or group of integers but not the exclusion of any other integer or group of integers.

It should be appreciated that the scope of the present invention need not be restricted to the particular scope of the embodiment described above.

Claims (69)

1. NOV. 2002 16:35 WRAY AND ASSOCIATES NO, 112 P. 6 -22- The claims defining the invention are as follows: 1. A roller bearing seal assembly to be located in the passage in the end of a roller shell to support the roller shell from a shaft, said roller bearing seal assembly comprising an outer seal assembly and a bearing, wherein the outer seal assembly comprises, a first annular member adapted to be non-rotatably supported on the shaft and which is located outermost, a second annular member adapted to be supported from the shell located closely adjacent the first annular member, the radial extent of the members being such that they overlap, wherein the outer seal assembly 10 further comprises a resilient flexible sealing element supported on the first or second annular member and being in slidable contact with the opposed :..face of the other annular member.

2. A roller bearing seal assembly as claimed at claim 1 wherein the sealing element defines a channel shaped surface between the first and second annular members which is directed radially outwardly.

3. A roller bearing seal assembly as claimed at claim 1 or 2 wherein the outer edge of the sealing element comprises a first lip seal which is radially innermost and which is in sliding contact with the other annular member, the sealing element further comprising a second lip seal which is radially outermost and is in sliding contact with the other annular member and is deflected radially outwardly.

4. A roller bearing seal assembly as claimed at claim 3 wherein the first lip seal is in light sliding contact with the other annular member. A roller bearing seal assembly as claimed at claim I or 2 wherein the outer edge of the sealing element is formed as a flange which extends radially outward from the sealing element, said flange being in sliding N ,sealinq contact with the other annular member.

WO 00/40487 PCT/AU99/01148 -23-

6. A roller bearing seal assembly as claimed at any one of claims 1 to wherein the sealing element is supported on the second annular member.

7. A roller bearing seal assembly as claimed at any one of claims 1 to 6 wherein the second annular member has a flange at its inner edge.

8. A roller bearing seal assembly as claimed at claim 7 as dependant from claim 6 wherein the flange at least partially supports the sealing element.

9. A roller bearing seal assembly as claimed at any one of the preceding claims wherein the sealing element is formed of formed from an elastomeric material or a material having elastomeric like properties.

10. A roller bearing seal assembly as claimed at any one of the preceding claims wherein the second annular member is adapted to be sealingly engaged with the shell.

11. A roller bearing seal assembly as claimed at claim 10 wherein the sealing engagement is provided by a resilient sealing medium supported from the second annular member.

12. A roller bearing seal assembly as claimed at claim 11 wherein, the sealing medium is bonded to the outer radial face of the second annular member.

13. A roller bearing seal assembly as claimed at claim 10 or 11 wherein the sealing medium is formed from an elastomeric material or a material having elastomeric like properties.

14. A roller bearing seal assembly as claimed at any one of the preceding claims wherein the second annular member is formed as a composite member comprising a rigid annulus and a moulding supported by the rigid annulus.

WO 00/40487 PCT/AU99/01148 -24- A roller bearing seal assembly as claimed claim 14 as dependant from claim 11 wherein the sealing medium is formed as an integral part of the moulding.

16. A roller bearing seal assembly as claimed claim 14 or 15 wherein the sealing element is formed as an integral part of the moulding

17. A roller bearing seal assembly as claimed at any one of claims 14 to 16 wherein the moulding is formed from an elastomeric material or a material having elastomeric like properties.

18. A roller bearing seal assembly as claimed at any one of the preceding claims wherein the outer seal assembly further comprises a rigid shaft seal adapted to be non-rotatably supported on the shaft and located between the first annular member and the bearing; wherein the shaft seal comprises a first annular flange extending radially outwardly from the shaft into the space between the second annular member and the bearing, said shaft seal having an outer radial surface which is closely adjacent the inner radial face of the second annular member, said shaft seal being configured to frictionally engage the first annular member.

19. A roller bearing seal assembly as claimed at claim 18 wherein the shaft seal is formed of a substantially rigid plastics material.

20. A roller bearing seal assembly as claimed at claim 18 or 19 wherein the shaft seal supports the first annular member from the shaft.

21. A roller bearing seal assembly as claimed at any one of claims 18 to wherein the outer radial surface comprises a second annular flange extending radially outwardly from the shaft such that its outer periphery is located closely adjacent the inner radial face of the second annular member. 1. NOV. 2002 16:35 WRAY AND ASSOCIATES NO. 112 P. 7

22. A roller bearing seal assembly as claimed at any one of claims 18 to 21 wherein the outer radial surface of the shaft seal and inner radial face of the second annular member have an axial extent.

23. An roller bearing seal assembly as claimed at any one of claims 19 to 22 as dependant from claim 7 or claim 8 wherein the flange at the inner edge of the second annular member provides the inner radial face of the second annular member.

24. A roller bearing seal assembly as claimed at any one of the preceding claims wherein the roller bearing seal assembly further comprises an 10 inner seal, said inner seal being intended to be located adjacent the S*innermost face of the bearing, said inner seal adapted to be non-rotatably supported from the shaft proximate the inner edge of the annular flange of the roller shell, the diameter of the outer radial face of the inner seal being such that the outer radial face is in closely spaced relation to the inner edge when the inner seal is in position in a roller shell, the axial dimension of the outer radial face of the inner seal being such that the outer radial face extends to either side of the inner edge when the inner seal is in position in a roller shell and the outer radial face is formed at the inner end of the inner seal relative to the roller shell with a first lip which is spaced inwardly relative to the roller shell, from the inner edge when the inner seal is in position in a roller shell.

A roller bearing seal assembly as claimed at claim 24 wherein the outer radial face is substantially parallel to the central axis.

26. A roller bearing seal assembly as claimed at claim 24 wherein the outer radial face is convergent in the direction of the first lip

27. A roller bearing seal assembly as claimed at claim 24, or 25, or 26 wherein the outer end of the outer radial face relative to the roller shell, is WO 00/40487 PCT/AU99/01148 -26- formed with a second lip which is spaced outwardly, relative to the roller shell, from the inner edge when the inner seal is in position in the roller shell whereby the outer radial face has a generally channel shaped configuration defined by the first and second lip and the portion of the outer radial face between the first and second lips.

28. A roller bearing seal assembly as claimed at claim 27 wherein the second lip is dimensioned to be in sliding sealing relationship with the outer radial portion of the bearing when the inner seal is in position in a roller shell.

29. A roller bearing seal assembly as claimed at claim 27 or 28 wherein the portion of the outer radial face between the first and second lips is convergent in the direction from the second lip to the first lip.

A roller bearing seal assembly as claimed at any one of claims 24 to 29 wherein the first lip is formed with a sharp outer edge.

31. A roller bearing seal assembly as claimed at any one of claims 24 to wherein the first lip is spaced outwardly from the inner edge a sufficient distance such that vertical plane containing the lower most extent of the first lip is spaced inwardly, relative to the roller shell, from the vertical plane containing the lowermost extent of the rotational path of the inner edge when the inner seal is in position in a roller shell and the roller shell is in use.

32. A roller bearing seal assembly to be located in the passage in the end of a roller shell to support the roller shell from the shaft substantially as herein described.

33. A roller shell having a bearing seal assembly of the form as claimed at any one of the preceding claims located in each end. 1. NOV. 2002 16:35 WRAY AND ASSOCIATES NO. 112 P. 8 -27-

34. A roller shell as claimed at claim 33 wherein the shell accommodates a breather which comprises an aperture formed through the end face of the roller shell to provide communication between the interior and exterior of the shell, said aperture being closed by a solid porous element.

35. A roller shell as claimed at claim 34 wherein the solid porous element is perious to air but is substantially impermeable by water.

36. A roller shell as claimed at claim 34 or 35 wherein the solid porous element is substantially impervious to water in both liquid and gaseous form. i 10

37. A roller shell substantially as herein described

:38. An outer seal assembly to be located in the passage in the end of a roller shell; wherein the outer seal assembly comprises, a first annular member adapted to be non-rotatably supported on a shaft and which is located outermost, a second annular member adapted to be supported from the shell located closely adjacent the first annular member, the radial extent of the members being such that they overlap, wherein the outer seal assembly further comprises a resilient flexible sealing element supported on the first or second annular member and being in slidable contact with the opposed face of the other annular member.

39. An outer seal assembly as claimed at claim 38 wherein the sealing element defines a channel shaped surface between the first and second annular members which is directed radially outwardly.

An outer seal assembly as claimed at claim 38 or 39 wherein the outer edge of the sealing element comprises a first lip seal which is radially innermost and which is in sliding contact with the other annular member, the sealing element further comprising a second lip seal which is radially WO 00/40487 PCT/AU99/01148 -28- outermost and is in sliding contact with the other annular member and is deflected radially outwardly.

41. An outer seal assembly as claimed at claim 40 wherein the first lip seal is in light sliding contact with the other annular member.

42. An outer seal assembly as claimed at claim 38 or 39 wherein the outer edge of the sealing element is formed as a flange which extends radially outward from the sealing element, said flange being in sliding sealing contact with the other annular member.

43. An outer seal assembly as claimed at any one of claims 38 to 42 wherein the sealing element is supported on the second annular member.

44. An outer seal assembly as claimed at any one of claims 38 to 43 wherein the second annular member has a flange at its inner edge.

An outer seal assembly as claimed at claim 44 as dependant from claim 6 wherein the flange at least partially supports the sealing element.

46. An outer seal assembly as claimed at any one of claims 38 to 45 wherein the sealing element is formed of formed from an elastomeric material or a material having elastomeric like properties.

47. An outer seal assembly as claimed at any one of claims 38 to46 wherein the second annular member is adapted to be sealingly engaged with the shell.

48. An outer seal assembly as claimed at claim 47 wherein the sealing engagement is provided by a resilient sealing medium supported from the second annular member. WO 00/40487 PCT/AU99/01148 -29-

49. An outer seal assembly as claimed at claim 48 wherein, the sealing medium is bonded to the outer radial face of the second annular member.

An outer seal assembly as claimed at claim 48 or 49 wherein the sealing medium is formed from an elastomeric material or a material having elastomeric like properties.

51. An outer seal assembly as claimed at any one of claims 38 to 50 wherein the second annular member is formed as a composite member comprising a rigid annulus and a moulding supported by the rigid annulus.

52. An outer seal assembly as claimed claim 51 as dependant from claim 48 wherein the sealing medium is formed as an integral part of the moulding.

53. An outer seal assembly as claimed claim 51 or 52 wherein the sealing element is formed as an integral part of the moulding

54. An outer seal assembly as claimed at any one of claims 51 to 53 wherein the moulding is formed from an elastomeric material or a material having elastomeric like properties.

An outer seal assembly as claimed at any one of the preceding claims wherein the outer seal assembly further comprises a rigid shaft seal adapted to be non-rotatably supported on the shaft and located between the first annular member and the bearing; wherein the shaft seal comprises a first annular flange extending radially outwardly from the shaft into the space between the second annular member and the bearing, said shaft seal having an outer radial surface which is closely adjacent the inner radial face of the second annular member, said shaft seal being configured to frictionally engage the first annular member.

56. An outer seal assembly as claimed at claim 55 wherein the shaft seal is formed of a substantially rigid plastics material. 1. NOV. 2002 16:35 WRAY AND ASSOCIATES NO. 112 P. 9

57. A roller bearing seal assembly as claimed at claim 55 or 56 wherein the shaft seal supports the first annular member from the shaft.

58. A roller bearing seal assembly as claimed at any one of claims 55 to 57 wherein the outer radial surface comprises a second annular flange extending radially outwardly from the shaft such that its outer periphery is located closely adjacent the inner radial face of the second annular member.

59. A roller bearing seal assembly as claimed at any one of claims 55 to 58 wherein the outer radial surface of the shaft seal and inner radial face of 10 the second annular member have an axial extent.

60. An outer seal assembly as claimed at any one of claims 55 to 58 as :dependant from claim 44 or claim 45 wherein the flange at the inner edge "of the second annular member provides the inner radial face of the second annular member. 15

61. An outer seal assembly as claimed at any one of the preceding claims wherein the roller bearing seal assembly further comprises an inner seal, 0:00 said inner seal being intended to be located adjacent the innermost face of the bearing, said inner seal adapted to be non-rotatably supported from the shaft proximate the inner edge of the annular flange of the roller shell, the diameter of the outer radial face of the inner seal being such that the outer radial face is in closely spaced relation to the inner edge when the inner seal is in position in a roller shell, the axial dimension of the outer radial face of the inner seal being such that the outer radial face extends to either side of the inner edge when the inner seal is in position in a roller shell and the outer radial face is formed at the inner end of the inner seal relative to the roller shell with a first lip which is spaced inwardly relative to the roller shell, from the inner edge when the inner seal is in position in a roller shell. WO 00/40487 PCT/AU99/01148 -31

62. An outer seal assembly as claimed at claim 61 wherein the outer radial face is substantially parallel to the central axis.

63. A roller bearing seal assembly as claimed at claim 61 wherein the outer radial face is convergent in the direction of the first lip

64. An outer seal assembly as claimed at claim 61, or 62, or 63 wherein the outer end of the outer radial face relative to the roller shell, is formed with a second lip which is spaced outwardly, relative to the roller shell, from the inner edge when the inner seal is in position in the roller shell whereby the outer radial face has a generally channel shaped configuration defined by the first and second lip and the portion of the outer radial face between the first and second lips.

An outer seal assembly as claimed at claim 64 wherein the second lip is dimensioned to be in sliding sealing relationship with the outer radial portion of the bearing when the inner seal is in position in a roller shell.

66. A roller bearing seal assembly as claimed at claim 64 or 65 wherein the portion of the outer radial face between the first and second lips is convergent in the direction from the second lip to the first lip.

67. A roller bearing seal assembly as claimed at any one of claims 61 to 66 wherein the first lip is formed with a sharp outer edge.

68. A roller bearing seal assembly as claimed at any one of claims 61 to 67 wherein the first lip is spaced outwardly from the inner edge a sufficient distance such that vertical plane containing the lower most extent of the first lip is spaced inwardly, relative to the roller shell, from the vertical plane containing the lowermost extent of the rotational path of the inner edge when the inner seal is in position in a roller shell and the roller shell is in use. WO 00/40487 PCT/AU99/01148 -32-

69. An outer seal assembly substantially as herein described.