EP0379569A4

EP0379569A4 - Cam follower assembly

Info

Publication number: EP0379569A4
Application number: EP19890908563
Authority: EP
Inventors: Werner B. Guilford
Original assignee: Roller Bearing Company of America Inc
Current assignee: Roller Bearing Company of America Inc
Priority date: 1988-07-12
Filing date: 1989-07-11
Publication date: 1991-07-17
Also published as: EP0379569A1; JPH03500329A; WO1990000689A1; JP2683130B2

Abstract

A cam follower assembly is provided which has a bearing outer ring (13) on an inner cylinder (23), with two rows of cylindrical rollers (17) therebetween. The rollers are held in place by inturned flanges (14, 15) at ends of the bearing outer ring. A thrust washer (25) is carried by the inner cylinder, and projects outwardly into a space between the two rows of cylindrical rollers, to accommodate endwise thrust load, such that endwise thrust is transferred between the bearing outer ring and the inner cylinder by passing through the rollers of a single row of cylindrical rollers. The inner cylinder is provided with a mounting shaft (16) adapted to be mounted in a carrier (11) and fastened together therewith.

Description

-1- CAM FOLLOWER ASSEMBLY BACKGROUND OF THE INVENTION

Due to machining tolerances and deflections under load, it is rarely possible to have a cam fol- 5 lower perfectly aligned with its track. The resulting misalignment causes thrusting of the outer ring. The invention minimizes the effects of outer ring thrust, such as wear and increased operating temperature, while improving sealing properties and load capacity. 10 In cam follower assemblies of prior art types, it is known to use a bearing assembly that has an outer ring disposed about a shaft, with one or more rows of cylindrical rollers between the shaft or inner ring and the outer ring. The bearing assembly, con- l***** sisting of outer ring, inner ring or shaft, and roll¬ ing elements, is retained together, generally by pressing L-shaped retaining washers into the outer ring flanges. Thus, the bearing assembly is held together by friction forces alone. Additionally, such 0 prior art devices, in the case in which more than one row of cylindrical rollers is used, cause the thrust load to be passed through both rows of rollers before transmission of such load to a flange or an end plate or washer. ⁵ Additionally, such prior art arrangements as described above inhibit the use of lip seals, espe¬ cially when such end plates or washers are used. Lip seals are generally desirable to retain lubrication within the bearing and to exclude external 0 contaminants. Where mounting of such seals is pre¬ vented or inhibited, the overall assembly becomes less desirable.

Additionally, if the press fit of the retaining washers is not sufficiently tight, or if the bearing 5 assembly is not axially clamped in the application, such prior art assemblies may become disengaged. -2-

SUMMARY OF THE INVENTION

The present invention provides a cam follower assembly in which the outer ring is mounted on a shaft, with a pair of axially spaced-apart rows of cylindrical rollers being disposed between the shaft " and the ring, with the outer ring having inwardly directed flanges at axial spaced-apart ends thereof, for purposes of accommodating end thrust, and wherein the shaft is provided with a ring mounted thereon and projecting into the space formed between the two rows of cylindrical rollers, and between the bearing outer ring and the shaft for accommodating end thrust from a row of cylindrical rollers. A mounting portion extends axially from the shaft, for mounting the cam follower assembly on a carrier member, and fastening means are provided for securing the same thereagainst. A portion of the cam follower assembly that comprises the shaft extends endwise farther than the outer end of the adjacent bearing outer ring, to provide a mounting shoulder for facilitating mounting the assem¬ bly against a carrier member. Suitable plugs and grease fittings, as well as longitudinal and transverse grease or other lubrication channels are optionally provided. Accordingly, it is a primary object of this invention to provide a novel cam follower assembly.^"

It is a further object of this invention to provide a novel cam follower assembly in which the thrust loads are handled between the outer ring and the shaft, through a single row of cylindrical rollers.

It is a further object to accomplish each of the above objectε, wherein a thrust ring is carried on the shaft. -3-

It is yet another object of the present inven¬ tion to accomplish each of the above objects, wherein a thrust ring extends axially outwardly into a space between axially spaced-apart rows of cylindrical rollers.

It is a further object of this invention to accomplish the above objects, wherein lip seals may be utilized together with thrust-absorbing flanges of the bearing outer ring. Other objects and advantages will be readily understood, upon a reading of the following brief description of the drawing figures, detailed descrip¬ tion of the preferred embodiment, and the appended claims.

-4- BRIEF DESCRIPTION OF THE DRAWING FIGURES

Fig. 1 is a longitudinal sectional view, taken through a cam follower assembly in accordance with this invention, wherein the assembly is mounted on a carrier member and secured thereto, by a suitable fastening member, with the carrier member being par¬ tially fragmentally illustrated, and with lubrication channels being illustrated in phantom.

Fig. 2 is an end view of the cam follower assembly of Fig. 1, taken from a left end thereof as viewed in Fig. 1.

Fig. 3 is a fragmentary longitudinal sectional view, similar to a portion of that of Fig. 1, but illustrating a modified cam follower assembly, in which there is less than a full complement of rollers in each row, separated by a cage, and which represents a modified version of the assembly of Fig. 1.

Fig. 4 is a fragmentary longitudinal sectional view of yet a further modified form of the assembly to that of Fig. 1 utilizing an alternative spacer ring arrangement to that of Fig. 1.

-5-

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring now to the drawings in detail, ref¬ erence is first made to Fig. 1, wherein the cam fol¬ lower assembly is generally designated by the numeral 10, carried by a suitable carrier member 11, within a' bore or through-hole 12, thereof.

The cam follower assembly 10 comprises a bear¬ ing outer ring 13, of cylindrical formation, with inwardly extending cylindrical flange portions 14 and 15, at axially spaced-apart ends thereof.

Disposed within the bearing outer ring 13, is an inner bearing member 16, of shaft-like construction.

Between the member or shaft 16 and the ring 13 are two annular rows of cylindrical rollers 17 and 18, disposed respectively against radially inwardly directed flanges 14 and 15, at inner ends 20 and 21, respectively, of the flanges 14 and 15.

A generally ring-like space 22 is thus pro- vided between the rows of rollers 17 and 18.

A split ring (i.e., having a substantially radial opening therein to accommodate the ring being stretched open over the periphery 23 of the inner bearing member or shaft 16) is provided, in snap-on relation to the periphery 23 of the shaft 16, in an annular groove 24 thereof, with the ring 25 extending radially outwardly into the space 22 between the .. rows of rollers 17 and 18, to retain the assembly securely and to accommodate the transmission of the load from the outer ring 13, and especially from one of the flanges 14 and 15 thereof, through only a single row of cylindrical rollers 17 or 18, through the thrust ring 25, and to the shaft 16 in which the ring 25 is mounted. -6-

A pair of seals 26 and 27 having single or multiple sealing lips are disposed in grooves as shown in the flange portions 14 and 15, with the seals 26 and 27 serving to retain lubricant therebetween, with the radial inner-most ends of the seals being disposed on the periphery 23 of the shaft 16 in shaft-wiping relationship, as shown.

The shaft 16 is provided with a shaft mounting portion 28 extending axially from one end thereof, and is provided generally with a threaded portion 30 on its right-most end thereof as viewed in Fig. 1 . A suitable fastener of the mounting nut type 31 or the like, is provided in threaded engagement with the portion 30 of the shaft, for securely mounting the assembly 10 on the carrier member, as shown. it will be noted that the shaft 16 is provided with a shoulder 32 as shown at right-most end, for engagement against a surface 33 of the carrier member, for secure mounting of the inner bearing member por¬ tion of the assembly 10 against the carrier member upon tightening of the fastening means 31. In this regard, it will be noted that the shoulder 32 extends rightwardly beyond the rightward longitudinal exten¬ sion 34 of the outer bearing ring 13, as shown in Fig. 1, in order to assure that the surface 32, rather than the surface 34, engages against the mounting surface 33.

Alternatively, the stud or shaft 16 could con¬ sist of a straight single diameter shaft with no shoulder 32, but with a snap ring or other retention device put into its place, which individually_.,or in conjunction with a hardened thrust washer engages the mounting surface 33.

An optional longitudinal lubrication channel 35 is provided, extending endwise of the shaft 16, from -7- one end to the other as shown in Fig. 1. A pair of transverse lubrication channels 36 and 37 are shown, extending from the lubrication channel 35, to the bore 12 of the carrier member 11 and the innermost axially spaced-apart end portions 38 and 40 of the rows of cylindrical rollers 17 and 18, respectively, the lat¬ ter for purposes of lubrication of the rollers 17 and 18 via a transverse channel 37.

At either end of the shaft 16 as illustrated in Fig. l, a grease or other lubrication fitting 41 may be attached, for facilitating introduction of lubricant into the channel 35, and the bearing proper and at the opposite end of the shaft 16, a plug 42 is provided, for removable engagement therein. At the left-most end of the shaft 16 as is viewed in Fig. 1, a slot 43 is provided for facilitating mounting and removal of the assembly 10 relative to its carrier member 11, by accommodating a screwdriver blade therein after removal of the fitting i.

It will be noted that the inner bearing member 23 of the shaft 16 is integral with the shaft 16, as is the axial extension 28 and threaded portion 30 thereof, preferably for constructing the assembly of a minimum number of parts.

It will also be noted that the thrust ring 25, together with the inwardly extending flanges 14 and 15 of the bearing outer ring, facilitates holding the assembly together. it will also be apparent that, with the arrangement described above, the thrust loads from the outer ring to the shaft, or the converse, may readily be accommodated through a single row of rollers, through the thrust ring 25. It will be apparent that the rollers 17 and 18 -8-

It will be apparent that the rollers 17 and 18 will generally be of hardened steel construction, and that the bearing outer ring 13 and inner shaft 16 will also generally be of metal, preferably steel construction, as will the thrust ring 25. The lip seals 26 and 27 will generally not be of metal construction, but may be of suitable natural or synthetic construction, of leather or suitable thermoplastic materials, such as neoprene or the like.

With reference now to Fig. 3, in detail, it will be seen that the assembly 50 comprises a bearing outer ring 51, with a thrust ring 52 disposed between rows of rollers 53 and 54, with the ring 52 being car- ried in an annular grove 55 in a shaft 56, as in the embodiment of Fig. 1, However, in the embodiment of Fig. 3, a cage 57 (well known per se) is utilized, having rightward extending portions and leftward extending portions 58 and 60, respectively, as illustrated, extending between and separating adjacent rollers 54 and 53, respectively, with the portions 58 and 60 being connected to a central circumferential portion 61. This arrangement allows the use of fewer rollers making up a row of rollers, with a plurality of cage portions separating adjacent rollers. In the use of a cage, such as in the arrangement of this embodiment, design variations are made possible, such as the ability to increase internal grease storage space, and in the spacing of rollers to facilitate high speed applications.

With reference to Fig. 4, another alternative embodiment is illustrated in the form of an assembly generally designated by the numeral 70, as comprising a bearing outer ring 71 disposed about a shaft 72, with a pair of rows 73 and 74, of rollers, spaced -9- apart by means of a thrust ring 75. The thrust ring 75 is provided with an inner annular groove 76 which faces toward a corresponding annular groove 77 in the periphery of the shaft 72. Within both of the grooves 76 and 77, is disposed a generally annular but polygonally shaped wire ring 78 (known as a "kinked wire"), which securely holds the ring 75 in place, and allows for transmission of thrust between the shaft 72 and one of the rows of rollers 73 or 74. The shaft 72 is of straight, single diameter, with no shoulder, but has a snap ring 79 in cylindrical groove 80, for engagement against a mounting surface (not shown) , like the surface 33 of Fig. 1, for example, either with or without a hardened thrust washer therebetween (not shown) .

It will be apparent from the foregoing that various modifications may be made in the details of construction, as well as in the use and operation of the present invention, all within the spirit and scope of the invention as claimed.

Claims

- 16-

WHAT IS CLAIMED IS:

1. A cam follower assembly comprising a bear¬ ing outer ring and an inner bearing member; with the bearing outer ring having a cylindrical inner surface disposed between inwardly directed flanges at axially spaced apart ends thereof and defining a cylindrical race for cylindrical bear¬ ing rollers therein; with said inner bearing member comprising a cylindrical member having a cylindrical outer periphery and a mounting shaft extending axially from an end thereof; a pair of generally parallel rows of bearing rollers mounted in axially spaced-apart relation defining a space there between and between the cylindrical outer periphery of said bearing member and the cylindrical inner periphery of the outer ring; a generally annular groove on the outer periphery of said inner bearing member; with thrust means disposed in said groove and carried thereby and extending radially outwardly thereof into the space between the rows of bearing rollers, for endwise thrust engagement therewith; and with said mounting shaft having fastening means thereon for facilitating the fastening said shaft to a carrier member for movement therewith.

2. The assembly of claim 1, wherein the end of said bearing member closest to said mounting shaft has a mounting shoulder which protrudes axially beyond the adjacent end of said bearing outer ring.

3. The assembly of claim 1, wherein, the end of said bearing member closest to said mounting shaft is of a transverse width larger than the transverse width of said mounting shaft. -I I -

4. The assembly of claim 2, wherein the end of said bearing member closest to said mounting shaft is of a transverse width larger than the transverse width of the mounting shaft, and whereby said shoulder provides means for compressive axial engagement against a carrier member to which it is adapted to be mounted.

5. The apparatus of claim 1, wherein said inner bearing member is provided with a generally longitudinally directed lubrication channel, and a transverse roller, lubrication channel communicating therewith, said transverse roller lubrication channel being longitudinally wider than the thickness of said ring, for lubrication of both rings of bearing rollers from the transverse channel.

6. The assembly of claim 1, wherein said inner bearing member is provided with a generally longitudinally directed lubrication channel extending longitudinally into said mounting shaft, and with a transverse shaft lubrication channel communicating therewith, said transverse shaft lubrication channel providing means for lubricating through internal pas¬ sages of the carrier member in which it is mounted.

7. The assembly of claim 1, wherein said flange each define generally radially inwardly directed annular portions.

8. The assembly of claim 7, wherein said annular portions are provided with annular grooves therein, with bearing seals being disposed in the grooves and mounted in wiping contact at opposite ends of the outer periphery of said inner bearing member.

9. The assembly of claim 1, wherein said thrust means is a split ring comprising means facilitating opening the ring for installation thereof.

10. The assembly of claim 1, wherein the thrust means comprises a thrust ring.

li. The assembly of claim 1, wherein the thrust means comprises:

(a) a ring disposed about the inner bearing member and having a circumferential annular groove on its inner periphery, opening toward the annular groove on the outer periphery of the inner bearing member; and

(b) a connector member disposed in both said annular grooves and connecting said ring to said inner bearing member, against relative axial movement.

12. The assembly of claim 11, wherein said connector member comprises a generally annularly configured polygonal, kinked wire member.

13. The assembly of claim 1, wherein said rows of bearing rollers are rows of circumferentially spaced-apart rollers, and including roller cage means between said bearing outer ring and said inner bearing member and including means spacing apart adjacent rollers in each said row.

14. The assembly of claim 1, where said •^• thrust means is a thrust ring, wherein the end of said bearing member closest to said mounting shaft has^"a mounting shoulder which protrudes axially beyond the adjacent end of said outer bearing ring, wherein, the end of said bearing member closest to said mounting shaft is of a transverse width larger than the transverse width of said mounting shaft, whereby said shoulder provides means for compressive axial engage¬ ment against a carrier member to which it is adapted to be mounted, wherein said flanges each define gener¬ ally radially inwardly directed annular portions, wherein said annular portions are provided with annular grooves therein, with bearing seals being dis¬ posed in the grooves and mounted in wiping contact at opposite ends of the outer periphery of said inner bearing member, wherein said inner bearing member is provided with a generally longitudinally directed lubrication channel, and a transverse roller lubrication channel communicating therewith, said transverse roller lubrication channel being longitudinally wider than the thickness of said ring, for lubrication of both rows of bearing rollers from the transverse channel, and; with a second transverse shaft lubrication channel communicating with said longitudinally direction lubrication channel, said transverse shaft lubrication channel providing means for lubricating through internal passages of the carrier member in which it is mounted.

15. The apparatus of claim 1, wherein the end of said bearing member closest to said mounting shaft has a mounting ring disposed on said shaft, and which protrudes radially outwardly of said shaft, from a location axially spaced from the adjacent end of said bearing outer ring.