AU611954B2 - Elastomeric combined seal and spring - Google Patents

Description

COMMONWEALTH OF AUSTRALLLI Jr PATENTS ACT 1952 Form COMPLETE SPECIFICATION FOR OFFICE USE Short Title: Int. Cl: Application Number: Lodged: Complete Specification-Lodged: Accepted: Lapsed: Published: Priority: o Related Art: a 9"a TO BE COMPLETED BY APPLICANT Name of Applicant: QUADION CORPORATION Address of Applicant: 3630 Wooddale Avenue South, St, Louis Park, MINNESOTA 55416, U.S.A.

aoo Actual Inventor: Richard Milton Boyd t Address for Service: GRIFFITH HACK CO.

71 YORK STREET SYDNEY NSW 2000

AUSTRALIA

Complete Specification for the Invention entitled: ELASTOMERIC COMBINED SEAL AND SPRING The following rtatement Is a full description of this Invention, Including the best method of performing it known to me/us:- 0697A:rk lA- I. DESCRIPTION BACKGROUND OF THE PRIOR ART High-speed, rotating metal parts have created lubrication, and consequently wear, problems for many years for the reason that they must be housed in metal bearings having a different coefficient of expansion. As a direct result thereof, the high speeds of rotation generate heat despite ,.tdequate lubrication between the :~parts, with the result that the opposed metal parts expand 1,1at a different rate, which permits the lubrication to ,,escape from the gear box in which it is contained. once the lubrication escapes, substantial. wear is experienced and the installation is doomed if the movement is con- ;tinued. similar problems are experienced with respect to installations utilizing high speed reciprocating movements.

seals located between such metal parts in the ':form of bearings, for accomnmodating such high speed relative movement over prolonged periods, can be advantageously formed of recently developed materials which have a high degree of inherent lubrication. Thus, a bearing product sold under the trademark VESPEL, although very costly and one which must be machined, will function as a seal under such conditions, provided it is urged gently and firmly but eontinuously against the sealing surface without excessive pressure,th laerbigacuef Lundue wear. However, experience has shown that no construction heretofore conceived or known would adequately furnish such a seal becauso no way was known for~ providing such gentle pressure continuously and substantially uniformly between metal parts having standard variations in dimensions, and over all of the temperature ranges generated during long periods of high speed movements. 'No way was known for automatically adjusting such pressure to compensate for dimensional changes over the gamut of temperature variations created within such parts.

t; S BRIEF SUMMARY OF THE INVENTION C. C 0-, C) -I 0i

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"Wherever hereinafter the terms "maximum normal cross-sectional dimensions", or "maximum normal radial dimension", or "maximum normal dimensions" are utilized, it is intended to connote the maximum distance measured from the outer surface of one of the corner lobes to the outer surface of an opposite corner lobe which is disposed in the same general plane extending at right angles to the working surfaces." "Wherever hereinafter the terms "minimum radial cross-sectional dimensions", or "minimum radial dimensions" are utilized, it is intended to connote the minimum distance measured radially between the opposed concave surfaces which are disposed between the convex corner lobes." "The term "normal" whenever utilized herein, is intended to connote a measurement taken in a plane extending at right angles to the working surfaces o! the ring." 2n 8425S:JM -27 I have found that any thermoplastic or thermosetting material having inherent self-lubricating qualities with a pressure velocity value of no less than 1800 at 100 feet per minute surface speed will generally provide an acceptable bearing for prolonged periods of highspeed movements, if it can be designed so tVat it will dimensionally adjust to dimensional changes caused by different coefficients of expansion and can be properly supported for that purpose. I have found that this can be accomplished by providing a resilient support for the bearing which will furnish the desired amount of pressure behind the bearing surface so as to maintain an adequate seal at the sealing surface without such pressure bu.ng excessive and hence without resultant undue wear, for all variations in the dimensions of the relatively moving parts and in the grooves in which such seals are to be installed. I have conceived of an elastomeric back-up sealing ring having critical dimensions which will satis- 20 ractorily adjust such pressure throughout the gamut of various speeds and variations in dimensions of the metal parts, of the groove, and of the ring Itself.

While compositions such as VESPE 2 have been known for sometime and while their self-lubricating features hitve been recognized, I have found that a mere annular bearing of such material will not compensate adequately for different coeaticients of expansion of opposed differert metals. As a consequence, I have utilized a splitring bearing which permits the circumference of the bearing to alter, However, I have found that even a split-ring bearing will not function adequately except under limited circumstances wherein the sealing surface of the bearing having the high degree of lubricity is urged against the sealing surface lightly but firmly and evenly,

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t -3despite variations in original dimensions of the installation components and variations caused by generated heat.

Even moderate pressures thereupon will cause undesirable wear circumstances. Although I have sought to utilize standard 0-rings or QUAD-Rings of standard sizes and configurations, I have found that none of them will function satisfactorily for they, either fail to apply adequate pressure initially, or they apply excessive pressures to the bearing when generated heat causes dimensional changes, because they either overfill the groove or become S, essentially a non-compressible rectangle, and thus exert greater radial pressure upon the bearing than it will ~withstand without undue wear.

S° I have found that if the bearing member is i5 comprised of a material having inherent self-lubricating qualities with a pressure velocity value of no less than 1800 at 100 feet per minute surface speed and is made in the form o4 a split-ring so that it can adjust circum- S ferentially, and if an elastomeric back-up ring mado of readily flowable material such as rubber and of proper critical dimensions is provided, then a long-lasting and effective seal for prolonged high speed movements can be provided. To obtain such a seal, I have deaigned the elastomeric back-up ring to be polygonal in crosa-section, 25 o£ substantially equal hransversa dimensions, with convex S corner lobes and opposed concave sides, tho degreas o£ concavit:! and convexity and the maximum and minimum radial dimensions having predetermined values within critical ranges. The back-up ring is substantially symmerical in cross-sectional shape.

According to a prefo£erred embodimetant o£ the present invention the critical radial distance between the two opposed radial spaced working surfacos of the ring is within the range 60 to 70 porcont of the mximm Iw radial distance between ovposed corners at one sido of the rin,1, although, preferably at 68 At 6S% the ring functions very well.

.f 7 ~v4 44 4 4 4 4 4 4 4 44~4 4 '1 40 4 4 4 4 4 00 4 4 04 4 44 4 4 4 4 4 4 44 04 4 4 44 4 I 44 4 41 4 4 44 4400 4 4 4 According to one aspect of the present invention there is provided: a combined seal and elastomeric spring for use in supporting relation with a self-lubricating bearing comprising: a one piece annular body composed of uniformly resilient, flowable rubber-like material throughout and constructed and arranged to be fitted into a sealing groove of ring-like configuration in supporting relation to an annular split-ring type bearing member with inherent self-lubricating qualities; said body having a generally right-angled polygonal cross-sectional configuration and having a pair of concave radially spaced surfaces and a pair of concave axially spaced surfaces; said body having convexly curved corner portions merging substantially tangentially with the concavities of said surfaces; one of said pair of surfaces constituting working surfaces each of which in its free form having a radius of concavity approximating 24%-30% of the maximum normal cross-sectional dimension between said pair of surfaces; the minimum cross-sectional dimension between said concave working surtaces in their noncompressed state being no more than 60%-70% of the maximum normal cross-sectional dimension bdtween said workirln suifaces.

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2 BRIEF DESCRIPTION OF THE DRAWINGS A detailed description of one preferred embodiment of the COMBINED SEAL AND ELASTOMERIC SPRING is hereafter described with specific reference being made to the drawings, in which: Fig. 1 is a vertical sectional view of a bearing, with a shaft shown in elevation therein for rotation at high speeds, and one of my combined seal and elastomeric springs installed in a groove of the shaft behind a selflubricating bearing-seal; Fig. 2 is a side elevational view of one of my combined seal and elastomeric springs in its free form; Fig. 3 is a vertical sectional view taken along line 3-3 of Fig. 2; Fig. 4 is a cross-sectional view on an enlarged scale of the ring shown in Figs, 2 and 3; Fig. 5 is a side elevational view of the bearingseal shown in Fig. 1 in its free form; Fig. 6 is a vertical sectional view of the bearing-seal, taken along line 6-6 of Fig. 5; and Fig. 7 is a top plan view of the bearing-seal shown in Figs. 5 and 6.

DETAILED D9SCRIPTION OF ThU PRBPiR InODXlN ,T Fig. 1 shows an insulation utilizing one of my combined seal and elastomeric springs. As shown# it includes a rapidly rotating metal shaft 10 which has an annular groove 11 formed in its exterior surface Opposite a metal bearing member 12 which surrounds the shaft while the latter is rotated at high speeds over prolonged periods of time. Typically, the bearing 12 hais a different coefficidnt of expansion than the metal from which -6the shaft 10 is formed and, consequently, the dimensional changes which result from the high speed and consequent elevations of temperature in each of these metals differ widely. As a consequence, the slight space which is provided between the two members 10 and 12, indicated as 13, which permits lubrication thurebetween, varies substantially in its dimension. Such substantial variations in dimensions permit, the lubricant to escape. As a result 0 thereof, the bearing member 12 will be destroyed unless 0 provision for preventing the escape of the lubricant is made.

To meet the above requirements, I provide sealing means which includes a split-ring bearing-seal member 14, which has an exterior circumference substantially equal to 1 5 the bearing surface of the bearing 12, at the space 13, This split-ring bearing member is self-adjusting and is formed of a self-lubricating material having selflubricating qualities with a pressure velocity of no less than 1800 at 100' per minute surface speed. As shown in Fig. 1, it is flat and is generally rectangular in cross- 000 sectional configuration and includes a tang 15 which extends axially outwardly therefrom into an opening 16 formed in the shaft 10 to accommodate same. This Lang ensures that the bearing momber 14 rotated with the shaft 10 within the bearing 12.

The split-ring bearing member 14 is shown in detail in Figs. 5-7. As besat shown in Vig. 7, it is split along a diagonal line 17 so that it has free end portI-is 18 and 19 which can move relative ho each other, bot% circumforentially and axially, thereby providing automatic adjustment to the dimensional changes resulting fron changes of temperature, when properly urged outwardly by my combined seal and elastic spring, which is shown betwean bearing 14 and the bottom of the groove 11. It will be seen that the bearing 12 and the shaft 10 provides sup- -7- ,port structure for the seal perfected therebetween by the .structure as shown in Fig. 1.

Disposed within the groove 11 in supporting relation to the bearing-seal 14 is one of my combined seal and elastomeric springs, indicated generally by the numeral This combined seal and elastomeric spring is comprised of a one-piece annular body which has a generally right angled pologonal configuration in cross-section, and is made of a flowable resilient material, such as rubber. In our practice, we utilize an elastomeric composition in Slieu of actual rubber. This ring 20 is of uniform cross- Ssectional shape throughout and, as best shown in Figs.

.i 3-4, is symmetrical. It will be seen that the ring has opposed concave sides 21 and which are working 1 surfaces and are radially spaced. I also has a pair of axially spaced concave sidos 23 and 24. Each or these concave sides merges gencrally tangentially with the cono vex corner lobes of tho rtng identified by the numerals 25-28.

"r Tho minimum radial dimension of tho ring 20 as measured between the bottom of the conecavities o£ the two opposed radially spaced saides 21 and 22, is 60%-7S% of the j imaximum normal radial dimension between said working sur- £faces. This maximum radial dimension, is measured as the 2S maximum distanco between the two opposed corners on either i side of the ring, au for examploe, the distance between i points identified by the numerals 29 and 30, in Fig. 4, The pre.Eerablo range o£ this minimum radial dimension is 65%-70% of said maximum radial dimension and the ideal minimum radial dimension at the bottom of the opposed cavities is 68% o£ that maximum radiai dimension, The corner lobes 25-28, inclusive, have convexities of 140-16% of the maximum radial distane between the working surfaces 21 and 22. The preferred convexity is 16% of£ that maximum radial dimension.

-8- The concavities of each of the four sides 21-24, inclusive, is substantial. These concavities may extend between a range of 17%-33% of the maximum normal radial dimension of the ring, as hereinbefore defined. The preferred range is 24%-30% of that dimension and the ideal range is 27%-29% of the same dimension. The preferred single dimension is 28% of the maximum normal radial dimension between the working surfaces.

with the dimensions as defined above, I have found that I can provide an effective, long lasting seal between metal surfaces, moving past each other at high speeds over prolonged periods. This movement can be the rotation of one pae past another as shown in Fig. 1, or may be a reciprocating motion where, for example, the seal is mounted in the exterior surfaco of- a piston and would appear as shown in Fig, 1. The design of the combined seal and elastomeric spring, such as the ring 20, is such as to provide a gentle back-up pressure upon the flat boaxing-sealing member 14 throughout the entire range of temperature, and consequent dimenslonal changes, experienced in such metal parts when operated at high speeds over prolonged periods. Thus, when such parts become hoateod, substantial dimensional changes take place, with the result that the bearing and sealing member 14, which is continually urged outwardly by the criticallydimensioned ring 20, will adjust circumferentially to compensate therefor. This is accomplished by a change in circumference of the bearing and 3oaling member permitted by shifting of the free ends 18 and 19 thereof relative to each other. At the same time, the combined sealing and elastomeric spring, in the form of the annular elastic ring 20, will adjust its amount of compression within the groove, it will be noted that the dimensions of the groove also will be altered by the ohanjes in tmperature.

Thos changes, plus the dimensional variations in the ini-

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-9tial construction of the shaft, the groove, the bearing, and the ring itself, comprise total variations for which compensations are extremely difficult. I have found, however, that a ring having dimensions within the critical ranges set forth herein, when utilized in combination with a combined seal and bearing, such as the member 14, will adequately compensate for such changes.

I believe that when such adjustments are required, the elastomeric material from which the ring i is manufactured flows into the substantial concavities o 21-24, r"-1,usive, which are provided in each of the sides of the ring. Since this material is readily flowable, but 44 S non-compressible, I have avoided the problem heretofore 9 o experienced with the standard QUAD-ring or 0-ring, none of which can adequately adjust to support such a bearing and S sealing member across the temperature ranges experienced, without applying undue pressure thereagainst, with consequent prohibitive wear.

It will be seen that the ring 20 also perfects a °2Q seal across the bottom of the groove 11, as well as at its S* top. Thus, it functions both as a seal and as an elastoo meric spring which is sufficiently sensitive and yielding t o ensure, in combination with the bearing 14, an adequate seal between the two relatively moving parts 10 and 12, over the entiro temperature range experienced in such installations when operated at various high speeds.

In considering this invention, it should be remomnbored that the present disclosure is illustrative only and tho scope o£ the invention should be determined by the appended claims.

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Claims (7)

1. A combined seal and elastomeric spring for use in supporting relation with a self-lubricating bearing comprising: a one piece annular body composed of uniformly resilient, flowable rubber-like material throughout and constructed and arranged to be fitted into a soaling groove of ring-like configuration in supporting relation to an annu- lar split-ring type bearing member with inherent self-lubricating qualities; said 00dy having a ;enerally right-angled poly- gonal croso-sectional configuration and having a pair of concave radially spaced surfaces and a pali of concave axially spaced surfaces said body havin& convexly curved corner portions merging substantially tangentially with the con- cavities of Paid surfaces; one of said pair of surfaces constituting work- ing surfaces each of which in its free form havin4 a radius of concavity approximating 24%-30% of the maximum normal crocs-sectional dimension between said pair of surfacesp te) the minimum diosiseenionaI dimn1ton bt.'woon aaid concavo working aurfaces in theAir non- compreasou state being no more than 60%7>% of the maximum normal c ei oal dimension between said working surfaces, ll -r p

2. A combined seal and elastomeric spring structure for use in supporting relation with a self-lubricating bearing comprising: a one-piece annular body of uniform, resilient flowable rubber-like material throughout and constructed and arranged to be fitted into a sealing groove of ring-like configuration in supporting relation to an annular split-ring type bearing member with inherent self-lubricating qualities; said body having a generally right-angled polygonal cross-sectional configuration and having a pair of concave radially spaced surfaces and a pair of concave axially spaced surfaces; said body having convexly curved corner portions merging substantially tangentially with the concavities of said surfaces; and one of said pair of surfaces constituting work surfaces and having minimum cross-sectional dimension therebetween in its non-compressea state being 60%-70% of the maximum normal cross-sectional dimension.

3. The structure defined in Claim 2, wherein said body is substantially symmetrical in cross-sectional configuration.

4. The structurn defined in Claim 2, wherein the 2S radius of concavity of each of said working surfaces in preferably 27%-29% of the maximum normal cross-sectional dimension between said working surfaces. The structure defined in Claim 2, wherein the radius of concavity of each of said working surfaces io approximately 28% of the maximum normal cross-sectional dimension between said working surfaces.

6. Tha structure defined in Claim 2, wherein the minimum radial cross-Aectional dimension between said concave working surfaces in approximately 6S% of the maximum radial cross-sectional dimension between said working 4 urfacS 8425MM

12- 7. The structure defined in claim 2, wherein the said working surfaces are spaced radially. 8. The structure defined in claim 2, wherein the minimum radial cross-sectional dimension between said concave working surfaces is approximately 65% of the maximum normal cross-sectional dimension between said working surfaces. 9. The structure defined in Claim 2, wherein the maximal axial dimension of said body equals the maximum radial dimension of said body when the latter is in its free form. The structure defined in Claim 2, wherein the radii of concavity of said surfaces in their free forms are equal. 1 13.. The structure defined in Claim 2, wherein the minimum cross-sectional dimension between said concave Q working surfaces is approximately 65%-70% of the maximum a~a radia3. cross-sectional dimension between said working surfaces.

2012. The structure defined in claim 2 wherein the a minimum cross-sectional dimension between said concave working surfaces is approximately 68% of the maximum normal cross-sectional dimension between said working surfaces. 13. A self lubricating bearing assembly comprising: a one-piece annular body composed of uniformly a a resilient, flowable rubber-like material throughout and constructed and arranged to be fitted into a sealing groove a of ring-like configuration in supporting relation to an annular split-ring type bearing member with inherent self-lubricating qualities; said body having a generally right-angled act*** polygonal cross-sectional configuration and having a pair off concave radially spaced surfaces and a pair of concave axially spaced surfaces#, 3S said body having convexly curved corner portions merging substantially tangentially with the concavities of said surfaces; and I' 4* *4 44 4 4 4 44 4 4 4* 4 44 one of said pair of surfaces constituting worlding surfaces and in their free form each having a radius of concavity approximating 17%-30% of the maximum normal dimension between said work~ing surfaces; support structure having an annular groove formed therein; an annular split-ring type bearing member sup- ported by said support structure and disposed within said groove; said bearing member having inherent self- lubricating qualities with a pressure- velocity value of no less than 1800 at 100 feet per minute surface speed; said body being disposed within said groove in support of said bearing with one of siaid working surfaces bearing against said bearing membe, and the other bearing against the bottom of said groove; and is is. 4 4 4 is, ~III *04 4 4 CC *0*0 "4 4 4 4 SW 4444 4 4 #44I~, ()the width of said groove being slightly greater than the maximum dimensions between the other of said Pair Of surfaces and the depth of said groove being slightly less than the combined radial dimensions of said bearing member and the M4Ximum normal cross-sectional dim~ansiots of said body whereby said body and said bearing are maintained under slight compression' 4 '14 ()The minimum cross-sectional dimensions between said working surfaces while in their non-compressed state, being approximately 60%-70% of the maximum normal cross-sectional dimensions therebetween. 14, A self lubricating bearing assembly comprising: a one-piece annular body composed of uniformly resilient, flowable rubber-like material throughout and constructed and arranged to be fitted into a sealing groove of ring-like con- figuration in supporting relation to an annular split-ring type bearing member with inherent self-lubricating qualities; sai.d body having a generally right-angled poly- ft gonal cross-sectional configuration and having a paro*ocae00*lysae urae n pair of concave axially spaced surfaces;ad said body having convexly curved corner portions merging substantially tangentially with the con- cavities of said surfaces; and d) one of said pair of surfaces constituting working surfaces and in their free form each 'having a L radius of concavity approximating 17%-30% of the 4. maximum normal dimension between said working surfaces; a pair of metal members mounted for high speed relative movement thezrebetween and having annular mating bearing surfaces between which said move- -is- ment takes place; ()an annular groove formed in one of sdid surfaces; said annular body being mounted within said groove at its bottom; a split-ring type bearing member being composed of plastic material having inherent self- lubricating qualities with a pressure velocity value of no less than 1800 at 100 feet per minute surface speed; said bearing member being mounted within said groove in supported relation to said annular body, and bearing against the other relatively moving metal member opposite said groove; ()the combined radial dimensions of said body and said bearing member being slightly greater than the depth of said groove- ()the axial width of said annular body being less than the width of said groove; the minimum cross-sectional dimension between said concave radially spaced surfaces while in their non-compressed state being approximaitely 1 44 60%-70% of th-maximum normal cross~.etoa dimension between said radially spaced surfaces. rhe structure dafined in Claim 15 wherein said bearing member has adjacdnt free end portions movable 4 -radially and axially relative to each other. 16. The structure defined in Claim 15 wherein said annular body is substantially symmetrical in cross- sectional configuration. 17. The structure defined in Claim 15 wherein said rd4-a-1Alsurfaces of said annular body in its non- compressed state have a radius of concavity of approxi- mately 28% of the maximum normal radial dimension between said working surfaces. 18. The structure defined in claim 15 wherein the minimum radial distance between said radially Spaced sur- faces of said annular body in its non-compressed state is approximately 68% of the maximum normal radial distance therobetween. 19. The structure defined in Claim 15 wherein the 0 0 maximum axial dimensions of said body in its non-compressed state is essentially equal to the maximum radial dimen- sions of said body. The structure defined in Claim 15 wherein said convexly curved corner portions of said annular body in its non-compressed state have a ra ,'us of curvature approximating 16% of the maximum normal radial distance between said radially spaced surfaces. 21. The structure defined inr claim 14 wherein said convexly curved corner portions of said annular body in its non-compressed state have a radius of curvature approximating 10%-16% of the maximum normal radial distance between said radially spaced surfaces. 22. A combined seal and elastomeria spring for use in supporting relation with a self-lubricating bearing, substantially as herteinbefore described with ref erence to the accompanying drawings. Dated this 30th day of October 1990. QUADION COR.PORATION 4 By their Patent Attorney GRIFFITH HACM CO. 4