US3319969A - Railway car journal box seals and the like - Google Patents

Description

y 1967 R. L. OLSON RAILWAY CAR JOURNAL BOX SEALS AND THE LIKE Filed Aug. 13, 1963 INVENTOR. 6/ c6 ar 0 1. 0/6017 I Y )/W ISb' ATT RNEYS United States Patent 3,319,969 RAILWAY CAR JOURNAL BOX SEALS AND THE LIKE Richard L. Olson, Chicago, Ill., assignor to Dilre-O-Seal Incorporated, Chicago, 11]., a corporation of Illinois Filed Aug. 13, 1963, Ser. No. 301,749 2 Claims. (Cl. 277-130) This invention pertains to seals for rot-ary shafts and more particularly relates to seals which are especially suitable for railway car axle journal boxes of the type conforming to standards of the Association of American Railroads. Such journal boxes are commonly equipped with an upright pocket at their inner ends for receiving an oil and dust seal.

Many and various oil and dust seal constructions have been proposed for railway car journal boxes. A general characteristic of prior such seals has been complex assemblies of parts, special relationships of materials and in most instances involving rigid components as well as yieldable components. With all their complexities and special forms and relationships of parts, prior journal box seals have, in addition to high cost for at least the more efiicient seals, all been unduly short lived, subject to wear and thus leakage in relatively short time in service, and most troublesome of all, have been unduly liable to destructive damage due to the often violent gyrations, oscillations and reciprocations of the journal relative to the journal box in running of the associated car.

Accordingly, it is an important object of the present invention to provide a substantially improved relatively low cost, simple and highly efficient journal box seal which overcomes the various deficiencies of prior journal box seals.

Another object of the invention is to provide a new and improved journal and like seal which is constructed entirely from cellular elastomeric material.

A further object of the invention is to provide a new and improved seal for railway car journal boxes which will retain its sealing relation to the journal in an unusually efiicient manner in spite of various gyratory, oscillatory and reciprocatory relative movements of the journal relative to the journal box.

Still another object of the invention is to provide a new and improved monolithic journal box seal which is efficiently self-centering in the journal box seal pocket.

A yet further object of the invention is to provide a new and improved seal for journals and shafts which is self-lubricating.

Other objects, features and advantages of the present invention will be readily apparent from the following detailed description of a preferred exemplary embodiment thereof, taken in conjunction with the accompanying drawing, in which:

FIGURE 1 is a fragmentary longitudinal sectional elevational detail view through a railway car journal box showing a seal according to the present invention in place in the seal pocket;

FIGURE 2 is a sectional elevational detail view taken substantially on the line 11-11 of FIGURE 1; and

FIGURE 3 is an enlarged fragmentary sectional detail view through the journal engaging inner margin of the seal member.

Referring to FIGURE 1, a railway car journal box 5 provides therein the usual oil chamber 7 receptive of saturated wicking, waste and the like, as is customary. At its front or outer end the journal box has the usual opening adapted to be closed by a door (not shown). Extending through an opening 8 in a double inner or rear wall 9 of the journal box defining an upwardly opening seal pocket 10 is a journal portion 11 joined by a larger diameter dry seat portion 12 to an axle 13 carrying adjacent to the seat a wheel 14. At its front end the journal portion 11 has a flange collar 15 between which and the fillet shoulder adjacent the dry seat -a bearing 17 is en gaged and supports a wedge 18 on which is mounted a top wall 19 of the journal box.

According to the present invention, a new and improved seal 20 is provided which is dimensioned to fit within the seal pocket 10 and about the dry seat 12 to prevent leakage of oil from the oil chamber 7 through the necessarily substantially oversize journal clearance opening 8, and to prevent dust and dirt from entering into the journal box through such opening. This seal 29 is desirably constructed as a unitary member of elastomeric, compressible construction, and more particularly of a suitable elastomeric plastic material comprising a body at least a major proportion of which has therein and especially in the journal engaging portions thereof small, discrete, predominantly closed, bubble-like gas filled cells whereby the material is bulk compressible as distinguished from merely fiowably deflectable as would be true of the elastomer as a solid mass free from the cellular structure. While a solid elastomer is deflectable, any deflections thereof are without change in volume. On the other hand, what may be termed as the essentially bubble filled elastomer of the seal 20 is bulk compressible, that is substantially reducible in volume under compression. This affords numerous salient advantages in a seal structure. Thus, the seal member 20 can be dimensioned to fill substantially entirely the containing space, in substantially confined relation, between the parallel walls defining the seal pocket 16, without need for expansion space as would be necessary with a solid, that is incompressible, elastomer seal in order to avoid binding, chafing, overheating, bursting, etc. to which solid elastomers under confinement are subject. Further, for the same size, the cellular elastomen'c seal 20 is substantially lighter in weight and requires substantially less material than if it were made of solid elastomer. Because of its inherent bulk compressibility, the cellular seal member 20 is capable of making closely conforming contact with opposing surfaces without undue pressures, tensions or stresses, whereby wear of the seal surfaces and the opposed engaged surfaces is substantially minimized. In fact, test of the cellular elastomer seal in the laboratories of the Association of American Railroads beyond the point of destruction of prior seals has failed to break down the cellular elastomer seal, and as is well known such tests subject the seal to greater punishment than anticipated under the most arduous running conditions.

Although the seal member 20 may be constructed with a substantially uniform fine discrete closed cell structure, it may be advantageously made of a partially open or interconnected cellular and combined closed cell in ternal structure. Among suitable oil resistant materials are polyurethane and synthetic rubbers. Among synthetic rubbers that are suitable are those identified by trade names Hycar (B. F. Goodrich Company) and Paracril (U.S. Rubber Company). Molding and blowing of such materials is known in the art. For synthetic rubber, formulations may include a suitable quantity of the rubber, a plasticizer, a vulcanizing agent and a gas liberating agent capable upon the application of heat of liberating substantial quantities of gas and thereby swelling or expanding the elastomeric composition. For a more detailed description of certain exemplary compositions and methods of molding reference may be had to my Patent No. 2,815,549 issued Dec. 10, 1957. While in that patent a method particularly adapted for main taining the molded member fixed in one side of a mold and releasable from the opposite side of the mold is dis- 6 closed, in the present instance, of course, molding must be effected in such manner as to have the seal member releasable entirely from both sides of the mold.

As best seen in FIGURES l and 2, the seal member 29, in this instance, is shaped substantially complementary to the seal pocket 1! of the journal box. Hence, the seal member 20 has opposite vertical parallel side edges 21, a generally semi-cylindrical bottom or lower edge 22 and a top edge 23. 'Both of the side edges 21 and the lower edge 22 are arranged by dimensioning of the width and height of the seal member to be in sufiicient clearance relation to the opposing wall surfaces within the pocket when the seal member is engaged about the dry seat 12 by a circular sealing edge 24 defining an opening through the seal member for this purpose. Through this arrangement, at least a limited practical range of sideward and downward movement of the seal member with the engaged journal in its operating gyrations relaitve to the journal box is permitted without placing any substantial compressive pressure on the seal member in its plane.

In order to resist rocking, turning movements of the seal member 20 about the axis of the journal, and excessive downward movement, suitable integral, preferably tapered, centering pads 25 are provided on the edges 21 and similar pads 26 on the edge 22, at spaced intervals. The pads 25 project from desirably the upper and lower end portions of the respective sides 21 into engagement with the opposing side walls defining the pocket 10. Similarly the pads 26 engage the bottom wall defining the pocket 10. All of these pads are compressibly displaceable into themselves or into the body of the seal member 20 or a combination of such compression into themselves and into the seal body. If preferred, the pads may be constructed as denser projections from the body of the seal member 20, or they may be constructed as more readily compressible and less dense projections, although for most purposes it will be sufiicient to have the density of the material in the pad projections 25 and 26 substantially the same as the density of the remainder of the body of the seal member, and more particularly that portion of the body of the seal member contiguous to the pads.

By virtue of their relatively small dimensions compared to seal edge area and their compressibly displaceable relation with respect to the body of the seal member 20, the pads 25 and 26 Will afford compression relief in the planar movements of the seal member 20 with the journal 11. This avoids such distortions in the seal member as might cause pulling of the journal-engaging internal annular sealing bearing edge 24 of the seal member away from the journal into leakage gap at the opposite side from that against which excessive compression force may be experienced during violent sideward and downward relative displacements of the journal and journal box in running operation, especially after the bearing portion of the journal and the bearing 17 have become worn.

For efiicient sliding, sealing engagement with the front and rear wall surfaces defining the journal box pocket 10, the seal member 20 is of a thickness complementary to the spacing of said walls. Such sealing engagement is effected in substantial depth outwardly relative to the edge defining the opening 8 both vertically and sideward- 1y. Moreover, by virtue of substantially complementary filling of the space between the upper portions of the parallel front and rear wall surfaces defining the pocket 10, the upper marginal portion of the seal member 20 and its upper edge 23 provide an effective top closure for the seal pocket 10. In this respect, the upper of the side edge pads 25 are desirably aligned with the upper edge 23 to complement the closure function of the upper margin of the seal member.

Desirably, at least the broad, parallel opposite faces of the seal member 20 are provided with an at least substantially impervious skin 27 (FIG. 3) to prevent leakage through the body of the seal member of oil from within the oil chamber 7 of the journal box, and also to prevent clogging of the material of the seal body with dust and dirt where a substantial proportion of the body is open cell structure. Of course, in a substantially entirely closed cell structure of the seal body the skin 27 need be no more than cell wall thickness of the closed cells defining such surfiaces of the seal member.

For improving sealing engagement of the inner journal-engaging edge 24 with the dry seat portion 12, such edge 24- is desirably formed on a diameter at least slightly smaller than the diameter of the journal seat portion 12. Because the cellular elastomeric material is bulk compressible, it readily expands about the engaged portion of the journal seat 12 without strain or stress and by virtue of the at least substantial proportion of closed cells in the material is highly resistant to tearing under the stretching tension adjacent the surface of the edge 24. Moreover, by reason of the bulk compression afforded by the closed cell structure, excellent sealing pressure uniformly about the entire annulus of the sealing edge 24 against the dry seat 12 is attained not only due to contraction of the elastic material but also due to the desirable increasing spring rate developed by compression of the closed gas cells in the compressed portion of the material.

Increased flexibility in the journal engaging edge 24, and thus improved following of the sealing edge portion of the seal member of any gyratory, eccentric, oscillatory movements of the journal relative to the journal box, without development of gap between any portion of the sealing edge 24 and the journal, is attained by having the edge 24 on a ridge or rib 28 of reduced thickness as compared to the principal thickness of the seal member 20, as best seen in FIGS. 1 and 3. To implement the bulk compressibility of the sealing ege area of the sealing rib 28 and to gain the advantage of flexibility both radially and axially relative to the journal opening in the seal member, one or both sides, and in this instance both sides 29 of the sealing rib projection 28 are of a concavely curved form, whereby the rib is narrowest adjacent the surface 24 and is progressively thicker toward its integral base juncture with the body of the steel member 20. Further, to relieve bending stresses, juncture of the surfaces 29 with the sides 27 of the seal member is preferably on a reverse, convex curvature 30 thus aflFording a substantially ogee curvature along the sides of the rib 28 with the major extent of the curvature comprising the inward, generally concave curvature 29.

Flexibility of the sealing rib 28 and its side contours afiord advantage also in facilitating assembly of the journal through the journal opening in the seal member, by easing of the sealing rib 28 over and past the collar flange 15 of the journal and then onto the dry seat portion 12 of the journal. Furthermore, in axial movements of the journal relative to the journal box and thus of the seal member 20 which is held in the journal box against any substantial movement axially with the journal, the axial resilient flexibility of the rib 28 as well as its range of resilient radial flexibility enables the sealing rib to maintain eflicient sealing engagement with the journal. Further, during unusual relative axial movements of the journal effecting shift of the-dry seat 12 inwardly or outwardly relative to the journal box 5 to the extent that the sealing rib 28 may come into proximity or engagement with the fillet shoulders at the opposite ends of the dry seat, the flexibility of the rib 28 and its curved contoured sides assures not only that sealing engagement will be maintained with the journal but that the rib will suffer no damage from movement against the fillet shoulders and will permit movement of the jourrial surface therethrough without seizing or doubling over or other deleterious reaction.

Although the size of individual, unconnected gas cells in the sealing rib 28 may be substantially the same as to size and distribution as the remainder of the internal structure of the seal member 20, for greater resilient flexibility air cells or bubbles 31 of larger diameters may be interspersed with or substantially uniformly developed in the sea-ling rib 28 and more particularly in the narrower crown area thereof. There may be a gradual transition of bubble size from the smaller bubbles interiorly of the main body of the seal member outwardly toward the sealing edge surface 24, or a more or less abrupt transition from the smaller to the larger bubbles, if preferred. An advantage of having larger size bubbles in the narrower more flexible portion of the sealing rib 28 as compared to the bubble size interiorly therefrom in the seal member 20 resides in that the spring rate of smaller bubbles is substantially higher, substantially progressively according to diminishing size, than the spring rate of larger size bubble cells. Accordingly, the multiplicity of the large gas filled bubble cells in the crown area portion of the sealing rib 28 afford :a desirable low spring rate which will easily accommodate and absorb the virtually continuous vibratory movements of the engaged journal in running without tending to similarly vibrate the entire :body of the seal ring disk member 20, enabling it to maintain a reasonably snug though slidable sealing contact with the opposing fiat parallel wall surfaces defining the journal box seal pocket 10. The sealing rib 28 may therefore be considered a vibration damping, shock absorbing annular area or portion of the sealing member 20.

To minimize frictional resistance and wear between the sealing edge surface 24 of the seal member and the socalled dry seat portion 12 of the journal, in spite of the fairly snug elastically gripping engagement of the sealing edge 24 with the journal surface and the generally relatively high coeflicient of friction of the elastomeric material, the construction and arrangement of the sealing edge 24 is desirably self-lubricating. Although from the very purpose of the seal to retain oil within the bearing and lubricating chamber 7 of the journal box, the dry seat name by which the journal portion 12 is known is indica tive of the fact that it may run dry and at least run with a low order of lubrication. Accordingly, the sealing edge surface 24 may be treated to a' suitable depth with a lubricating substance such as graphite, molybdenum disulphide, tungsten powder, platinum, lead, zinc, beads or spheres of silicone, and other materials having low coefficients of friction. On the other hand, a simple and quite effective self-lubricating arrangement comprises utilizing at least a portion of the area within the sealing rib 28 as an oil reservoir. This may be elfected by impregnating the open cellular structure adjacent the surface 24 Where at least a proportion of the material is of porous open cellular structure and the surface 24 is free from a skin or has a porous skin. On the other hand, where the internal structure within the sealing rib 28 is substantially entirely closed cell and the sealing surface 24 is with or without a definite skin, impregnation with lubricant in fluid, semiliquid or particulate form is adapted to be effected through perforations 32 of any preferred depth extending inwardly from the surface 24 and through at least some of the bubble cells, such as the cells 31. In FIGURE 3 the perforations 32, for illustrative purposes, are illustrated in highly exaggerated form. Actually, such perforations may be no more than pin pricks sufficient to puncture the superficial surface 24 and underlying bubble cells. A fairly uniform pattern of the perforations 32 throughout the annulus of the surface 24 affords best results.

Impregnation of the punctured cells with lubricant may be effected in any suitable manner such as by compressing the crown portion of the seal rib 28 to drive out gas within the punctured bubbles while the rib is immersed in the lubricating material so that when the compression pressure is released the lubricant will be sucked into the punctured voids afforded by the cells. Probably a more efiicient manner of effecting lubricant impregnation rather quickly is by subjecting the perforated rib 28 to a vacuum whereby to withdraw gas from the punctured cellular structure, and then restoring normal, or even a higher atmospheric pressure while the sealing rib and more particularly the sealing surface 24 is immersed in the lubricant, thus attaining substantially uniform impregnation.

For highest efficiency, the perforations 32 are of a depth which extends inwardly a substantial distance beyond the anticipated compression line or diameter as indicated by 12 in FIGURE 3 (representing the dry seat surface 12 of FIGURES 1 and 2) to which the sealing surface 24 will normally be expanded and thus the contiguous crown area of the rib 28 compressed in service. Such compression squeezes some of the lubricant out onto the sealing surface 24 and between the sealing surface and the engaged journal or shaft surface. Then, in the relative radial movements of the rotary surface and the sealing surface 24 pressure ejection of lubricant from the oil reservoir through the perforations 32 acting as fountain orifices in response to inward pressure brings additional lubricant to the surface. Excess lubricant is sucked back into the reservoir through the orifices 32 which act as suction openings on relief of pressure and expansion of the sealing rib during the eccentric, vibratory relatively radial movements of the sealing surface 24 and the engaged rotary surface. There is thus in running operation a lubricant ejection-suction action through the lubrication well porosity afforded within the sealing surface 24, which is highly efficient, especially in respect to the journal seal where there is a more or less continuous generally low order, but at higher speeds higher order of relative eccentric movement between the journal and the seal member 20.

Ifdesired, at least some lubrication well orifice perforations 33 may be provided in the side surfaces 29 of the sealing rib 28 for lubrication when such surfaces engage during relative movement with a surface of the journal.

While a considerable range of proportion of closed cells to the volume of the body of the seal member 20 may be provided, it should be understood that the smaller the bubble-like cells are and the more uniform their distribution, the stronger will be the resulting structure of the material, and more particularly its tear strength. Excellent results are attained where the upper limit for the diameters of the effective preponderance of the hubbles may be on the order of about 0.02 to 0.03 inch to thereby benefit by the rapidly increasing resistance against bursting and the flexural strength thus attained. The lower size limit, particularly for low percentages of confined gas, is a practical one, depending on the ability to form interbubble walls of correspondingly reduced thickness with the chosen material and by the particular expanding, blowing or bubble forming technique employed and may be on the order of 0.001 inch diameter or some What less for strong material and relatively thick bubble walls. Generally, it is simpler to form the bubbles more or less uniformly throughout the mass, except at the progressive transition or boundary region as it merges into the skin areas of the member. The particular ranges of sizes need not apply to every closed cell since a small percentage, such as 10% to 15% or more, may be undesirably too large or too small without adverse affect, as long as the effective preponderance of the bubbles are in the preferred range of sizes. Nitrogen filled bubbles are desirable.

As will be observed, the exemplary form of the gen erally slab-like ring disk journal box seal member 20 is symmetrically formed, especially in respect to substantially identical opposed axially facing sides, so that it is readily reversible. This not only simplifies and eXpedites assembly but enables reversal of the seal member should it be found during servicing of the equipment that one side has sustained more wear or has been subjected to some wearing abuse in service. Generally, however, it will be found that unless there has been some unusual malfunction of the contiguous equipment or a damaged part or surface engaging the seal member, little wear will be evident on the axial sides of the member even after prolonged service, assuming, of course, that the proper elastomeric material has been selected for the anticipated operating conditions for which the associated equipment is to be used.

It will be understood that modifications and variations may be effected without departing from the scope of the novel concepts of the present invention.

I claim as my invention:

1. In a railway car journal box having an opening therethrough about which is a seal pocket and a rotary journal extending through said opening into the journal box and subject to relative movements in respect to said box during rotary operation:

a sealing member substantially complementary to and mounted within said pocket;

said sealing member'including a body of compressible elastomeric material having an opening through which said journal extends and defined by an annular portion having an edge sealingly gripping said journal;

said body having substantially uniformly distributed therethrough small gas-filled closed bubble-like cells, with the cells in said annular portion being of substantially larger size than the cells in the body surrounding said annular portion so that said annular portion is more flexible than the remainder of the body to permit relative easily following movement of said annular portion with the journal in said relative movements of the journal and relative to said remainder of the body;

said remainder of the body being of substantially greater thickness than said annular portion as well as having smaller cells therein;

said edge being normally cylindrical;

said annular portion having a substantially ogee curvature on its sides from said edge to said remainder of the body;

and perforations extending into and through said edge and through said sides into some of said larger cells and lubricant being in said larger cells into Which said perforations extend.

2. A compressible elastomeric railway car journal box seal comprising a unitary body of generally ring disk slab form adapted to be mounted within the usual journal box seal pocket:

said body having a central circular sealing edge defining a journal opening and adapted to engage a journal sealingly;

outer vertical substantially parallel edges and a lower generally semi-cylindrical edge joining the lower ends of said vertical edges;

said vertical edges and lower edge being adapted to remain normally in substantially spaced relation to opposing surfaces within the journal box seal pocket; said vertical edges and said semi-cylindrical edge both having a plurality of spaced projecting spacer andcentering pads which are short and have substantially longer intervening edge portions therebetween and are engageable with the respectively opposing surfaces within said seal pocket to afford compression relief in the planar movements of the seal member with the journal whereby to avoid undesirable distortions in the seal member which might cause pulling of the journal-engaging sealing edge away from the journal into leakage gap at the opposite side from that against which the excessive compression force may be exerted during violent sideward and downward relative displacements of the journal and journal box in running operation and especially after the bearing portion of the journal and possibly the bearing within the journal box have become worn.

References Cited by the Examiner UNITED STATES PATENTS 2,997,755 8/1961 Olson.

3,010,741 11/196'1 Hoyer '277-237 3,022,097 2/1962 Seniff et al. 27710 X 3,108,813 10/1963 Brown et al. 2771 3,220,786 '11/ 1965 McCutchen 308240 FOREIGN PATENTS 1,263,660 5/1961 France.

SAMUEL ROTHBERG, Primary Examiner.

Claims (1)

1. IN A RAILWAY CAR JOURNAL BOX HAVING AN OPENING THERETHROUGH ABOUT WHICH IS A SEAL POCKET AND A ROTARY JOURNAL EXTENDING THROUGH SAID OPENING INTO THE JOURNAL BOX AND SUBJECT TO RELATIVE MOVEMENTS IN RESPECT TO SAID BOX DURING ROTARY OPERATION: A SEALING MEMBER SUBSTANTIALLY COMPLEMENTARY TO AND MOUNTED WITHIN SAID POCKET; SAID SEALING MEMBER INCLUDING A BODY OF COMPRESSIBLE ELASTOMERIC MATERIAL HAVING AN OPENING THROUGH WHICH SAID JOURNAL EXTENDS AND DEFINED BY AN ANNULAR PORTION HAVING AN EDGE SEALINGLY GRIPPING SAID JOURNAL; SAID BODY HAVING SUBSTANTIALLY UNIFORMLY DISTRIBUTED THERETHROUGH SMALL GAS-FILLED CLOSED BUBBLE-LIKE CELLS, WITH THE CELLS IN SAID ANNULAR PORTION BEING OF SUBSTANTIALLY LARGER SIZE THAN THE CELLS IN THE BODY SURROUNDING SAID ANNULAR PORTION SO THAT SAID ANNULAR PORTION IS MORE FLEXIBLE THAN THE REMAINDER OF THE BODY TO PERMIT RELATIVE EASILY FOLLOWING MOVEMENT OF SAID ANNULAR PORTION WITH THE JOURNAL IN SAID RELATIVE MOVEMENTS OF THE JOURNAL AND RELATIVE TO SAID REMAINDER OF THE BODY;

Images