WO2000017076A1

WO2000017076A1 - Idler bearing damaging substance ingress shielding facility and shielded idler

Info

Publication number: WO2000017076A1
Application number: PCT/ZA1999/000093
Authority: WO
Inventors: Deon Van Rooyen
Original assignee: Deon Van Rooyen
Priority date: 1998-09-21
Filing date: 1999-09-17
Publication date: 2000-03-30
Also published as: AU6299999A

Abstract

A shielding facility for shielding a shaft and rotor assembly 10 comprises a shaft mountable cover providing formation (12) and a rotor engageable cover providing formation (14). The formation (12) presents a sealed socket (16) and a flange portion (20) formed to overlap substance ingress counteracting fashion with respect to a convolution contributing portion in the form of a formation (14.1) of the cover providing formation (14) once the facility (10) is operatively fitted. The formation (14) presents a central bearing cage (24). The formations (12) and (14.1) are formed to overlap in both the axial and transverse directions with respect to their common axis of operative fitting (34), once operatively fitted, by defining a convoluted radial passage (36) extending between circumferential sets of matchingly ribs (38, 40) as extending integrally from the flange portions (20, 22) of the respective formations (12, 14.1).

Description

(1) TITLE OF THE INVENTION

Idler bearing damaging substance ingress shielding facility and shielded idler

(2) BACKGROUND TO THE INVENTION

Rotatable assemblies such as conveyer belt idlers are often used under conditions of exposure to harsh environmental circumstances. This may include dust of sludge or other substances that can often quickly cause deterioration in the bearings of such equipment owing to ingress of such substance thereto. One location of ingress where idlers are fitted with equipment to counteract such ingress is along the end of a shaft onto which the drum of the idler is rotatably mounted. Another possible path of ingress is between parts of the equipment. In the process of limiting the ingress of unwanted matter to bearings it must be borne in mind that any friction must be limited as much as possible as a large number of idlers are usually involved under normal operating conditions. A small frictional effect is thus multiplied extensively that, in turn, has an effect on the operating load on drive equipment. It is thus an object of this invention to address, amongst others, the discussed problems.

(3) FIELD OF THE INVENTION

This invention relates to a shielding facility for protecting at least one annular zone between at least two relatively rotatably mounted members, also mounted against relative axial displacement, and of which one is a shaft, against undesired substance ingress. The invention also relates to a rotatable assembly incorporating one or more shielding facilities. Although not so limited the invention finds useful application in counteracting the ingress of undesired substance to the bearings of an idler.

(4) PRIOR ART DESCRIPTION

Various forms of protection are used to counteract ingress of damage creating material into the interior of a rotatable item to limit bearing wear. In all the methods known to the inventor unwanted material access still takes place along two paths. This is along the shaft via its support and between ingress limiting configurations fitted to the end of a rotating member. In the case where ingress is counteracted via lubricant material as packed into such configurations, the present methods, as far as known to the applicant, do not attempt to minimise the frictional effect via such lubricant.

(5) BRIEF DESCRIPTION OF THE DRAWING

The invention is now described, by way of example, with reference to the accompanying drawings. In the drawings

Figure 1 shows in sectioned side elevation full line exploded view and partly broken line assembled view a shielding facility, according to the invention, in the form of a shaft and rotor assembly shielding facility as provided by a shaft mountable cover providing formation and a rotor engageable cover providing formation,

Figure 2 shows the convolution contributing portion, in the form of a releasable formation, of the non-shaft rotatably mounted member engageable formation, as provided by a rotor engageable formation, in end view along arrow A in figure 1 ,

Figure 3 shows the shaft mountable formation in end view as viewed in the direction indicated by arrow B in figure 1 ,

Figure 4 shows in sectioned detail the engagement of the formations of figures 2 and 3 into the facility though only on one side of the central axis of the facility,

Figure 5 shows in sectioned side elevation the operative fitting of the shielding facility to one end of a shaft and rotor assembly, as forming part of the assembly, and

Figure 6 shows in partly cut-away view a shaft and rotor assembly as incorporating a shielding facility at opposite ends in the form of a conveyer belt idler. (6) DETAILED DESCRIPTION OF THE DRAWINGS

Referring to figures 1 to 4 of the drawings, a shielding facility for shielding a shaft and rotor assembly, is generally indicated by reference numeral 10. The shielding facility 10 comprises a cover providing formation arrangement in the form of cover providing formations as provided by a shaft mountable cover providing formation 12 and a rotor engageable cover providing formation 14. The formation 14 is fitted with a releasable convolution- contributing portion in the form of a seperable formation 14.1 providing the convoluted passage, as discussed below, in conjunction with the formation 12. The formation 12 presents an end sealed socket 16 defined by a socket defining portion 18 locatable onto the stub of a shaft, as discussed in detail below, and a fiange portion 20 extending circumferentially from the portion 18. The flange portion 20 is formed to overlap substance ingress counteracting fashion with respect to the formation 15 once the facility 10 is operatively fitted and as shown in more detail in figure 4.

The formation 14, as sealably engageable with a rotor along its outer edge 14.2, presents a circumferentially formed inward extending flange portion 22 in conjunction with the formation 14.1 while defining a central bearing cage 24 as presenting a bearing shoulder 26 against which a bearing 28, shown in broken lines in figure 4, urges in response to the effect of the shaft carrying core 30 of the formation 12 as presenting a bearing inner race bearable shoulder as provided by a ridge 32 to promote unobstructed rotation of the bearing 28, once the facility 10 is operatively located. Once the facility 10 is operatively fitted axial movement of the formations 12, 14 with respect to one another and especially into coming into contact with one another, is prevented by the formation 12 being securably to a shaft as fitted to the socket 16 while the bearing 28 is locked in the bearing cage 24 by the effect of the shoulder 26, on the one side, and of the ridge 32 of the core 30 from the other side.

The object of the facility 10 is to minimise undesired substance ingress to the annular zone between rotatably mounted members fitted with the facility 10 and in particular to limit such substance from reaching a bearing 28 as shown in broken lines in figure 4. To achieve this object the formations 12 and 14 are formed to overlap in both the axial and transverse directions with respect to their common axis of operative fitting 34, once operatively fitted, by defining a convoluted radial passage 36 extending between circumferential sets of ribs 38, 40 as extending integrally from faces 42, 44 provided by the flange portion 20 of the formation 12 and the formation 14.1 as forming part of the flange portion 22 of the formation 14 once fitted thereto. The ribs of the rib sets 38, 40 are thus matchingly spaced to result in their intermeshing with one another, though without coming into contact, as clearly shown in figure 4, once the facility 10 is operatively fitted.

It will be appreciated that the facility 10 requires the application of specific design parameters for a certain shaft and rotor assembly to obtain the desired intermeshing effect between the rib sets 38, 40 to ensure that the passage 36, on the one hand, gives adequate clearance to prevent the ribs of the opposite rib sets 38, 40, coming into contact while, on the other hand, keeping the path of ingress as constricted as possible.

While substance can still penetrate the shielding effect of the facility 10 once operatively fitted, it will be appreciated that the convoluting effect of the passage 36, once the facility 10 is operatively fitted, substantially limits ingress as compared to a passage that is not so constricted. As discussed below, the passage 36 can in the appropriate case also by packed with lubricant packing even further limiting such ingress.

Especially in the case where the passage 36 is packed with lubricant, though not so limited, the lubricant performs a frictional effect between the rib sets 38, 40. In the case of only one rotatable member as fitted with facilities 10 this effect is negligible. But where a large number of rotatable members are used, such as conveyor belt idlers, the effect becomes marked. A method of limiting this effect is to limit the radial extent of the passage 36 while still retaining its effect in curtailing the ingress of undesired substance. To this end the cover providing formations 12, 14 are formed to cause the radially extending convoluted passage 36 to extend from adjacent the outside wall of the socket-defining portion 18 of the formation 12. The rib set 38 as extending form adjacent the portion 18 thus meshes with the rib set 40 as extending from the inlet to the bearing cage 24. To operatively fit the bearing 28 the rib set 40 must be removed. For this reason the rib set 40 is carried by the formation 14.1 that is seperable from the body of the formation 14 by being clip fashion received into the inlet to the bearing cage 24 and held in the clipped position by means of a clip rib 41 extending integrally from the inner face of the bearing cage defining wall 14.3 of the formation 14. The clip rib 41 is suitably positioned along the bearing cage wall to result in the formation lying snug against the bearing 28 once fitted to the cage 24 and the formation 14.1 operatively clipped in position.

In also referring to figures 5 and 6 a shaft and rotor assembly fitted at opposite ends with a shielding facility 10 as forming part of the assembly, in the form of a conveyer belt idler is generally indicated by reference numeral 46. The idler 46 is thus constituted by a rotor in the form of a cylindrically shaped drum 48 rotatably mounted to a shaft 50 via the facilities 10. The formations 14 of each facility 10 are sealably fitted to opposite ends of the drum 48 and rotate in conjunction with the drum 48 once the idler 46 is operatively used. The formations 12 carry the opposite ends of the shaft 50 by way of their stub ends 50.1 as received within the sockets 16. The idler 46 is operatively mountable by way of the outside area of the socket defining portion 1 δ.The drum 48 is rotatably mounted to the shaft 50 by means of bearings 28 as held in the bearing cages 24 of the formations 14 via their bearing shoulders 26 and ridges 32 of the formations 12. The formations 12, 14 are thus mounted against axial movement in the direction of reducing the size of the passages 36. Relative movement between the formations 12, 14 in a direction of effectively opening up the passages 38 is prevented by the stubs 50.1 being locked to their respective formations 12 (not shown) while the formations 14 firmly engage at opposite ends to the drum 48.

Especially in the case of idlers, but not limited thereto only, environmental conditions can result in undesired substance such as dust penetrating the annular zone 52 between the drum 48 and the shaft 50 and thus the bearings 28, causing their rapid deterioration. The idler assembly 10 of the invention, however, counteracts such substance penetration. As the stubs 50.1 of the shaft 50 are carried in enclosed sockets 16 such substance cannot reach the bearings 28 via this path. The only paths of access are along the radial passages 36. As already discussed above, the composition of the shielding facilities 10 has the effect of counteracting unwanted substance penetration of the annular zone 52 in which the bearings 28 are located owing to the convoluted layout of the passage 36. When environmental conditions warrant it the passages 36 can be packed with lubricant packing. As discussed above, in such case the frictional drag of the lubricant is effectively reduced as compared to the situation where the labyrinth path would have been provided at a larger spacing from the axis 34.

Claims

(7) CLAIMS

(1 ) A shielding facility for protecting at least one annular zone between at least two relatively rotatably mounted members, also mounted against relative axial displacement, and of which one is a shaft, against undesired substance ingress comprising,

a cover providing formation arrangement incorporating at least two cover providing formations of which the one is end on mountable against substance ingress and relative axial displacement to such shaft while extending in an overlapping substance ingress counteracting though non-touching relationship with the at least one other cover providing formation, mountable end on against substance ingress and axial displacement to such other member, to limit ingress to such annular zone along the passage formed between the overlapping sections of the formations while permitting unobstructed relative rotational motion between them, once the formation arrangement is operatively mounted with the non- shaft mountable formation, in the appropriate case, making provision for central shaft passage there along.

(2) A shielding facility as claimed in claim 1 in which the cover providing formation that is end on mountable to a shaft (the shaft mountable formation) is mountable by means of a socket formed there along into which the stub of such shaft is sealably receivable and further being conventionally clampable to a shaft support, the facility, once operatively located limiting undesired ingress into an annular zone between such shaft and such other rotatable member by preventing end-on ingress via the stub of such shaft owing to its sealing location down the socket of the shaft mountable formation and counteracting ingress along the passage defined between the overlapping portions of the formations with the shaft mountable formation thus being mounted on the outside of the other formation in relation to the position of such other rotatable member as making provision for central shaft passage there along, once the facility, such shaft and such other rotatable member are formed into an assembly that, in the appropriate case, incorporates a facility at opposite ends.

(3) A shielding facility as claimed in claim 1 or claim 2 in which the cover providing formations present circumferentially extending overlapping sections formed to result in the provision of a generally radially extending passage, once the formations are operatively fitted.

(4) A shielding facility as claimed in claim 3 in which the. cover providing formations are formed to cause the passage formed between them, once operatively fitted to two relatively rotatably mounted members, to extend in both an axial and transverse direction overlapping relationship with respect to the central axis along such members.

(5) A shielding facility as claimed in claim 4 in which the cover providing formations are formed to overlap into causing the passage to extend in a convoluted way via convolution contributing portions as forming part of each of the cover providing formations once the facility is operatively fitted thereby to define a generally ingress counteracting labyrinth path.

(6) A shielding facility as claimed in claim 5 in which the circumferentially extending overlapping sections are presented by flange-type portions extending at least substantially transverse to their respective axes of fitting from their rotatable member fitting portions between the overlapping portions of which the passage along which ingress of undesired substance is desired to be counteracted is formed once the facility is operatively fitted.

(7) A shielding facility as claimed in claim 6 in which the cover providing formations are formed into causing the passage to extend in a convoluted way by way of concentric rib layouts standing proud of faces provided by the flange type portions as facing one another and intermeshing without touching once the facility is operatively fitted.

(8) A shielding facility as claimed in any one of claims 5 to 7 in which, at least where the convoluted passage, formed once the facility is operatively mounted, is intended to be packed with a lubricant to improve the ingress counteracting effect of the facility once operatively mounted and in use, the cover providing formations are formed to cause the radially extending convoluted passage to extend from in close vicinity if not just beyond the outside wall of the socket defining portion of the shaft mountable formation and only to a desired extent to effectively counteract undesired substance ingress, once the facility is operatively mounted, thereby to limit friction between the formations as operatively mounted and in use via such lubricant.

(9) A shielding facility as claimed in any one of claims 5 to 8 in which the non-shaft member engageable formation presents a bearing carrying cage for holding a bearing by means of which a non-shaft rotatably mounted member, as provided by a rotor, is mounted to a shaft as passing along such bearing once the facility, such rotor and such shaft are assembled into a shaft supported rotor assembly with such rotor thus being so rotatably mounted to such shaft via the rotor engageable formation as engaging with such rotor, the convolution contributing portion of the rotor engageable formation being releasable from the body of the rotor engageable formation at least in the case where the overlapping between the cover providing formations extends from within close vicinity if not just beyond the outside wall of the socket defining portion of the shaft mountable formation to permit operative location of such bearing within the cage in response to removal of this portion and subsequent repositioning once such bearing has been located within the bearing carrying cage.

(10) A shielding facility as claimed in claim 9 in which axial displacement between the formations, once operatively mounted, into closing the passage is counteracted by the shaft carrying formation providing a shoulder along its outside surface coming to urge against the inner race of a bearing as fitted to the bearing cage at a suitably critical spacing from its convolution contributing portions to ensure effective limitation of the size of the passage defined between the formations without permitting their coming into physical contact.

(11) A shielding facility as claimed in any one the preceding claims in which the shaft carrying formation is mountable to a shaft against relative axial displacement by making provision for its locking to the end stub of such shaft once fitted down the socket of this formation.

(12) A rotatable assembly comprising at least two rotatably mounted members of which one is in the form of a shaft, mounted against relative axial displacement, fitted at opposite ends with a shielding facility of which each is provided by a cover providing formation arrangement incorporating at least two cover providing formations of which the one is end on mounted against substance ingress and relative axial displacement to the one end of the shaft while extending in an overlapping substance ingress counteracting though non- touching relationship with the at least one other cover providing formation, mounted end on against substance ingress and axial displacement on the same side to the other rotatably mounted member to limit ingress to the annular zone defined between the members along the passage formed between the overlapping sections of the formations while permitting unobstructed relative rotational motion between them with the non-shaft rotatable member engaging formation, in the appropriate case, making provision for central shaft passage there along.

(13) A rotatable assembly as claimed in claim 12 in which each cover providing formation that is end on mounted to the shaft (the shaft mounted formation) is mounted by means of a socket formed there along into which the appropriate stub of the shaft is sealably received with this formation further being conventionally clampable to a shaft support, each facility limiting undesired ingress into the annular zone between the shaft and the rotatable member by preventing end-on ingress via each end stub of the shaft owing to its sealing location down the socket of its shaft mounted formations and counteracting ingress along the passage defined between the overlapping portions of the formations, the shaft mounted formation thus being mounted on the outside relative to the non-shaft rotatably mounted member engageable formation in relation to the position of the rotatable member with the non-shaft rotatable member engaging formations making provision for central shaft passage there along.

(14) A rotatable assembly as claimed in claim 14 in which the cover providing formations of the arrangements present circumferentially extending overlapping sections formed to result in the passages extending generally radially.

(15) A rotatable assembly as claimed in claim 14 in which the cover providing formations are formed to result in the passages formed between them to extend in both axial and transverse overlapping directions with respect to the central axis of the rotatably mounted members.

(16) A rotatable assembly as claimed in claim 15 in which the cover providing formations are formed to overlap into causing the passages extending in a convoluted way via convolution contributing portions as forming part of each of the cover providing formations thereby defining generally ingress counteracting labyrinth paths.

(17) A rotatable assembly as claimed in claim 16 in which the cover providing formations of the arrangements present flange-type portions extending at least substantially transverse to their respective axes of fitting from their rotatable member fitting portions with the passages along which ingress of undesired substance is desired to be counteracted extending between the overlapping portions of the flanges.

(18) A rotatable assembly as claimed in 17 in which the cover providing formations are formed to result in the passages extending in a convoluted way by way of concentric rib layouts standing proud of faces provided by the flange type portions as facing one another and intermeshing without touching.

(19) A rotatable assembly as claimed in claims 16 to 18 in which, at least where the convoluted passages are intended to be packed with a lubricant to improve the ingress counteracting effect of the facilities once the assembly is in use, the cover providing formations of each arrangement are formed to result in its radially extending convoluted passage extending from in close vicinity if not just beyond the outside wall of the socket defining portion of its shaft engaging formation and to only to a desired extent to effectively counteract undesired substance ingress thus limiting friction between the formations once the assembly is in use via such lubricant.

(20) A rotatable assembly as claimed in any one of claims 16 to 19 in which each rotor engaging formation presents a bearing carrying cage in which the bearing by means of which the non-shaft rotatably mounted member, as provided by a rotor, is rotatably mounted to the shaft as passing along the bearing, is held with the rotor thus being rotatably mounted to the shaft via the rotor engaging formations as engaging from opposite ends of the rotor, the convoluted passage defining portion of each rotor engaging formation being releasable from the body of its rotor engaging formation, at least in the case where the overlapping between the cover providing formations of each cover providing arrangement extends from within close vicinity if not just beyond the outside wall of the socket defining portion of its shaft engaging formation to permit operative location of the bearings within their cages in response to removal of these portions and subsequent re-positioning once the bearings have been located within the bearing carrying cages.

(21 ) A rotatable assembly as claimed in claim 20 in which axial displacement between the formations of each arrangement into closing the passage is counteracted by the shaft carrying formation providing a shoulder along its outside surface coming to urge against the inner race of the appropriate bearing as fitted to the bearing cage at a suitably critical spacing from its convolution contributing portion to ensure effective limitation of the size of the passage defined between the formations of each arrangement without permitting their coming into physical contact.

(22) A rotatable assembly as claimed in any one of claims 12 to 21 in which the shaft carrying formations are mounted to the shaft against relative axial displacement by being locked to the end stubs of the shaft.

(23) A shielding set comprising the at least two cover providing formations of any one of claims 1 to 11.

(24) A rotatable assembly as claimed in any one of claims 12 to 22 which is in the form of a conveyor idler.

(25) A shielding facility substantially as described with reference to the accompanying drawings.

(26) A rotatable assembly substantially as described with reference to the accompanying drawings.