CA1060814A - Rigid segmented brake disk - Google Patents

Abstract

A RIGID SEGMENTED BRAKE DISK

ABSTRACT OF THE DISCLOSURE

A friction segmented brake disk has a plurality of arcual segments which are rigidly fastened together by a tongue extending from at least one end portion of the seg-ment and is received by an adjacent segment recess and fastened thereto by at least two fastening members.
In another embodiment, a rigid friction brake disk contains a plurality of arcual segments which have a slot in each end portion thereof. A clip engages the slots and is connected thereto by a fastening member.

Description

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BACXGROUND' OF THE~ INVENTION
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The present invention relates to segmented brake disks wherei'n the 'segments are fastened to each other in such a manner that a rigid disk is formed'. Mo're 'specifically, the segments are'connected to each other such tha't .the axial width 'o~ the'entire'disk 'is the: same'throughout.
. Heretofore in the'field of brake 'disk applica$ions such'as in je~ aircraft, both 'commercial and military, com- .
parable'disks have'generally been made 'as one 'continuous unitO
Not only does -such a construction tend to be'expensive,' but such brake 'disks are 'subject to. hi'gh 'thbrmal induced stresses as well as shear at bending stres:ses and are'subj'ect to failure'during operation.
Another type of disk'construction utilizes seg~
mentea disks to avoid thèse problems. :'However, in many of..
these seymented disk constructions, .tongue 'induced stresses collectively contribute 'to potential failure.' Additionally, several constructions of segmented brake.'disks tend to be

2~ costly,.require external clips or fasteners and thus contain additional complexity and are'cumber'some with respect to ease of assembly, installation and replacement.

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SUMMARY OF THE INVENTION
. _ It is, therefore, an object of an aspect of the, present invention to provide a segmented brake disk which is easy to assemble and install in a brake disk stack.
It is an object of an aspect of the present invention to provide a segmented brake disk, as above, which is circularly rigid.
It is an object of an aspect of the present invention to provide a sesmented brake disk, as above, which has a constant axial width throughout.
It is an object of an aspect of the present invention to provide a segmented brake disk, as above, wherein the segments are connected by a tongue extending from some of the segments and engage a recess located in some of the segments.
It is an object of an aspect of the present invention to provide a segmented brake disk, as above, wherein the tongue is located in one end portion and the recess is located in another end portion of a segment and both are located in the periphery thereof.
It is an object of an aspect of the present invention to provide a segmented brake disk, as above, wherein the tongue and recess are secured by at least two fastening members.
It is an object of an aspect of the present invention to provide a segmented brake disk, as above, which retains a circular, rather than an elliptical configuration when removed from its driving means and thus facilitates installation into a normally circular wheel, gear or pulley.
It is an object of an aspect of the present invention to provide a circularly rigid segmented brake disk having a constant axial width throughout and in which the segments are connected by clips.

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~ 2-~, ,, ~0~ 4 It is an object of an aspect o~ the present invention to provide a segmented brake disk, as i~nedia-tely above, in which the end portions of the segments have slots and wherein fastening members connect the clips to the segment recesses.
It is an ob~ect of an aspect of the present invention to provide a segmen~ed brake disk, as above, in which the homogeneous segmented disk efficiently transfers heat from the surface to the core of the segment.
These and other objects of the present invention are described in detail without attempting to discuss all of the various embodiments in which the invention might be embodied; the invention being measured by the appended claims and not by the details of the specification.
In general, a segmented brake disk is characterized by: a plurality of segments, a gap existing bet~een said segments, said segments having two end portions, a periphery, and a width, said segments having a tongue and a swept area, said tongue having an axial width less than said segment width, said tongue extending from one of said segment end portions, said swept area having inherent high thermal ex-pansion and contraction forces, a recess having an axi~l width less than said segment width, said recess located in said remaining segment end portions, said tongue residing in said recess, said tongue located at said periphery of one of said end portions substantially outside said swept area on said segment, said recess located at said periphery of said remaining end por-tion substantially outside said swept area ~ -3-on said segment,,and at leas~.two separate fastening means for securing each said tongue'to each said segment end portion hàving said recess to form a rigid connection sub-stantially outside said swept area of said segment so that said connection is outs~de said high thermal expansion and contracti.on ~orces.

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IO~C~ rl7~ or~ T DRAW}NGS

Fig~ 1 is a plan view ~f a segmented rotor brake disk. ~, Fig. 2 is an enlarged plan view o~ Fig. 1 ~howing a single segment having a tongue ancl ~ recess.
Fig. 3 is a plan view of a s~at~r brake di~k having wear pads therebn.
Fig. 4 is a top elevatio~ view of a segment.
F~g. 5 is-a crossws~ctional view taken in line:5~5 of Fig~ l:showing t~e a~tac~ment o~ one segmen~ to another~
Fig. 6 is a plan view :sho~ing a portion of a ~egmented brake disk utilizing a clip to. connect the segments.
Fig. 7 is. a cross-sectional ~iew taken in line 6-6 of Fig. ~ showihg the:a~ach~ent of t~e clip to the segment.
DESC~IPTION O~ THE ~REF~RRE~ EM~DI~ENTS ;

The concepts of the present i~vention generally relate to a circularly rigid segmente~ br:ake disk having at least a tong~e extending from some of t~e segments, at least a recess 2~ located in some of the segments with t~ tongues connec:t~a to the segment recesses to generally form an annular rigid brake disk having ~ood s~ability and facili~ating wheeI
assembly. An individual segmen~ may contain O, l, or a plurality of tongues and/or recesses and are arra~ged, of 2~ courseD to ~orm a rigid tsngue-recessed connection which lies within the planes of the disk wear or frictIonal surfaces.

A preferred embodiment of the present:invention is shown in Fig~ 1 wherein the 'segmeIited brake' disk i~ generally indicated by the' numeral 10. 'The disk contains a plurality o segments ll, whLch'are connected in such'a- manner that a gap 12 exists be~ween the ends 13'thereof. The'gap, of course, prevents deformation o~ the segme~ts and disk as a whole due t~ the effec~s of heat buil~ up a~d co~ling as well as from the'resultin~ mech'anical stresse~' encountere~. ~hat is, . during a breakîng operatio~,,all sur~aces rubbed by linings experience'a substantial heat build-up, which ~upon cooling causes arcuate shrinkage in steeL disks. 'Such'shxinkage when restraine~ as in a'non-segmented disk generates stresses of a magnitude to. deform the 'initial-ly flat disk into ei~her a "BeIleville"' washer or a wave.washex configuration. This change of flatness i~ deIeteriou~ t~ proper brake operation and causes lost running clearance'and he'nce dragging wi~h resultant fires and disk'failure.' Generally,,but not neces'sarily, the 'periphery of se~ment 11 is arcual as in t~e''tongue o~ the'segments and hence the'segment~ are'generally referred t~ in the'art as bei~g arcual~
As best shown in Fig. 2,.,se~ment 11 has a ton~ue,' generally indica~ed by the n~meral 15, extending ~rom one of th~ end portions 13.' Additionally~,a rece's's:generally in dicated by the numeral 16 extends Lnward int~ ~he disk~rom the other end portion and ha~ a s~ape corres'ponding to that of *he tongue. Generally, t~e tongue has an arcual ~0 8 surface 17 which coincides with:thQ periphery of the segment~
Additionally, tongue 17 contains a portion of a U-shaped groove indicated by the numeral 18 which~along with a remain-ing portion 19 appearing on an adjacent :segmentiof the U-shaped groove, consti*utes a groove, generally indicated bythe numeral 20, for the acceptance o~ a keyway, not shownQ
The tongue termina~es in essentially a radial surface 21 and has an arcual or curvilinear porti:on 2~ which gives way to essentially a linear inwardly aper2d sur~ace 2~. Generally, the slope of tapered surface:23 is no~ importa~t as long as a sufficient radially distance is maintained from U~shaped portion 18 as well as axial thïckness to provide sufficient structural integxity to th~ tongue and to pre~ent it:from failing at this point.
Recess 16 contains a surface,. generally i~dicated by the numeral 25. Recess surface:25 generally corresponds ~o the tongue sur~aces but extends su~ficiently int~ the segment such :that a small gap exis~s between th~ tongue and recess snrface 25 ta compensate for e~pansion of segments. Thus, recess 25 contains a ra~ial surface;~7.which ex~ends radially inward int~ the:se$ment, a curvilinear or arcual surface 28 and an inwardly tapered linear surfac~:2g which extends to an end portion of the segment opposite the :~ongue end portionO
Although tongue 15 may exist on one axial side of the segment an~ reside i~ a recess lS whi:ch exists in the oppo-site axial side of an adjacent ~egment,: or in any other variation, in the.pre~erred embodiment ~s best shown in Fig.

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4, the tongue exists within the central axial portion of the segment as does recess 160 Additionally, as apparent from Fig.2,pre~erably the tongue and ~he recess exists near or at the periphery of the segment so that during operation, S the engagement o~ a tongue 15 wi~h a ~ecess 16 is not su~jected to frictional forces. ~his provision pro~ides a reIatively cool engagement between the tongue and recess-portions and t~ere~y eIiminates the necessity o~ using very low stress allowables which are attendant with hi:ghly eleva-ted temperatures. This also minimizes shrinkage effects.
In ge~eral, a conventional fastening member is -utilized to connect tongue 16 to ~ecess walls 31, as be t shown in Fig. 5. A desirable fastening member is simply a pin or rivPt 32 which is deformed to reside within an outward taper or countersunk portion 33 existing in the axially outer portions or flanges of the segment as well as apera~ure 33 in the tongue. In order that the connection between the tongue and recess resul~s in a rigid connection, at least two p~in~s of co~nection are required such as two rivets. Of course, any ot~er type of fas~ening mem~ers may be utilized and it is to be understood that ~hbuld a weld line exist,;the line, of course, is made up of a series of points and thus provides at least two sep~rat~ point~ of connection or engagement.-The segments, including the tongue and the ri~ets may bè made of conventional heatsink material such as metallics, for example, steel, a carbon composi~e material and combination~

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thereof as well understood by one skilled in th~ art~
Furthermore, although in the~pref:erred embodiment shown, the segmentea disk relates to a rotor which is utilized in a brake disk stack, not shown, the segmente~ disk according to the concepts of the present invention may also be util.ized for a stator wherein, preferably~ the t~-ngue and rece~s conne.~tion exist~ near or around t~è inner radial surface.
A stator which may be utilized in connection wit~ the segmentea disk lO, is generally indicate~ by the numeral 40.
1~ . The stator has U-shaped grooves 41 ~ocat2d on the inner radial and, of courser recei:ves keyways, not :shown. Stator 40 may be made of the same materials as :t~e rotor. In the embodiments shbwn, the stator is a continuou~ annular disk and contains wear pads 42.thereon. These pads may be` made of a conventional material such a frutermets:, cereme~s, or-ganics and the like, with the rotor being made from steel.
Of coursa, wear pads of steel, are no~:desired since they generally pro~ide a low coeficient of-friction, a~d produce gouges or grooves in adjacent di~k surfaces. A~ ~hown in 2~ Fig. 3, th~ wear pads may be readily att~che~ to a continu-ous:s~ator as :throuyh rive~ 43.
It is also withïn thQ scope of the present i~ven~ion to provide tongue an~ recess e~gagements ot~er than tha~
shown in the preferred embo~iment~ For eXample, a particular segmen~ may have a tongue locatea in each end portion and engage an adjacent:segment whLch contains two correspond-ingly shape~ reces~ses located in each end portion.

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Additionally, rat~er than a single tongu~ and recess connec-tion on any one end portion of adjacent .segments, a plurality of such tongue and recess engagements may exist. Additionally, the tongue and recess portion may exist at any other loca-tion than near or at the periphery of ~he.:segments. Fur~her~more, the tongue portion and the recess may be shape~ differ-ently, so long as generally a sufficient radial -length~exists to provide sufficient struct~ral integrity to prevent cracking or shearing of the tongue. Of course,: combina~ions of 1~ these various embodLment~ may also exist~
. As preYiously noted, t}le ~segmentad brake disk may be made out of any suitable heat sink material such a~ s~eel or a carbon based material. Shoul~ a carbon base ma~erial be:utilizèd, it preferably is a carbon composite material or a laminated structure made from a carbon base~ material and layers-of fiber in accordance with we:Il known con~entional practice. Desirably,.the carbon bas.~d ma~erial may be coal tar pitch, petxoleum pitch, uran resin, poly~crylontrile~ and mix tures thereof as well as any other materials which have a 2û high coking value and can b~ pyrolyzed ta yield essan~ially a carbon material. By a high coking value is meant the material which upon pyrolization will yiel~.at least 30 per-cent of its initial weigh~ as carbon and preferably at.least 50 percent. The fiber layer whIch also may be made accord-ing to any conventional practice:and exists as car~on clothmay be a fibered layer. containing matexials known to .t~e art whïch may be pyrolyzed ta a carbon cloth. Speciic ex-_g_ . .

amples include rayon, polyacrylontrile fiber, combinationsthereof and t~e like. In general, the:carbon composite la~er is made by repeatedly inpregnating the fiber layer with the carbon based material and heating t~ pyrolyze the ba~e mat-5 erial to essentially carbon~ After repea~ed operatLons, acarbon composite article is pro~ucean Alt~ough the tongue portions of t~2 various se~ments may be connected by carbon plugs, principally metal rivets are preferred in accordance with conventional practiceO
There~ore, bushi~g may be utilized to engage the bore or aper~ure of the tongue and th~ reces:sed side walls to prevent wear with the rivet, of course~ being located within the bushing.
In another. emb-odiment o tke present invention, a segmented brake disk whic~ may be ut~ ed as prefer ~ly a rotor or less desirably as a stator, and made of the same material as in the`embbdilEIent se~ f~rt~ in Fig~. 1, in this embodiment. The Pnd portions ~f the segments have a slot and a clip e~gages *he slots and is secured ther.eto by a fa~tening member to form a rigid brake disk.:
Referring to Fig. 6,.a portion of a segmented disk brake is generally indicated by the nume~al 50 a~d has seg-ments 51 separate~ by a gap 52.: The segments: which are generally arcual are connected t~rough their end portions 55 to form an annular brake disko Pre~erably, a slot generally indicatea by the numeral 56, resides within the end portions at or near the periphery of each :segme~t. ~ particul~r and 6'8:~

preferred slot is shown in Fig. 6. Generally, the slot com-prises a radially surface 57, a cu~ilinear or arcual portion 58 and an inwardly tapered linear porti:on 59 which extends tQ end portion 55. As shown in Fig. 7, slot 56 is pre~era-bly located in the axial central portion of the disk although~of course, ot~er locations may b~ utilized. Addi~ionally, the slot may have ~arious differen~ s~apes and configura~ions.
A keyway groove 65 generally exists in the periphial . vicinity of end portions 55 between the:segment~ as shown in 1~ Fig.-6. Of course, if the particular disk involved was a stator, in accordanc~ with :conventional prac~i~e, ~he keyway grooves may be located on the in~ernal ~iameter of a disk.
The clips which join the segments are generally in-dicated by the numeral 70 and preferably, but not necessarily, made of the same material as th~ segments. Generally, clip 70 has the same shape ox configuration as slot 56 except ~hat it is of a s}ightly smaller size s:uch:.~hat a slight gap 71 exist~ between the clips 70 and ~lot 56 for ease of assembly and to compensate for expansion o~ *he:segmen~s. Thus, in the preferred embodiment depicte~ in Fig. 6,: clip 70 has a radial surface:73, a curvilinear or arcual surface 74 and an inwardly tap-ered linear sur~ace .75 which::generally ex~ends to gap 52 between the segments and *hen abruptly i~ tapered ou~wardly in a linear mann@r with th~:remaining por~io~ of the clip generally being a mirror -image or symmetrical with respect to the:just described p~rtion. In an alternative em-bodiment, surface 75 may be linear and perpendicular with respect to a radii passing through :gap 52 or it may be arcual.
In any event, it contains a groove 77 which is similar to keyway groove :65. In general, groove 65 is U-shaped and is o~ the same breadth or size as ~lot 56 so that it ensages a keyway, not shown~
Clips -70 are connected to segments 51 t~rough any conven~ional fastening member as weLl known to thos~ skilled in the art. In the preferred embodiment, the connecting or fastening m~mber is a rive~ 78 which resides with an aperture 79 of the segment and aperture 8~ o~ the:clip as shown in Fig. 7. Desirably, the aper.tures wi~hin the se~men~ may be ~apere~ axially outward, as shbwn,. ~o provide a counter-sink e~fe~t. In order that the brake disk be rigid, each segmen~ contains at least tWQ connection points as in the embodiment of Figs. 1 thr.ough 5.
A brake disk made according t~ the construction shown in Fig. 6 and 7 as well as wit~ the construc~ion set forth i~ Fig~. 1 through 5,: contains connected segmen~s such that the axial width of the en~ire disk is prefe~abIy the same ~hroughou~.. Moreo.ver, th~ disk:se~ forth ~n Figs. 6 and 7 may be used in ass~ciation wi~h the:st~tor as shown in FigO

3 in a brake disk stack such as tho.se conventionally utilize~
in j et aircraft..
It-is al so within t~e scope o~ the present in~ention 2~ to provide a clip and slot engagement o.~ar than ~hat-shown in *he preferred embodiment. For example, the particular segment may have a clip located at:other portions alon~ end portions 55. Additionally, rat~er than a single clip and slot, a plurality of clips and slQts may exist.. Moreover, the configuration of the clip~ and ~s~ots may vary generally so long as the clip has a sufficien~ radial length and axiaI
thickness to provide sufficient s~ructural integri~y and there~y prevent failure of the clip during operation of the brake disk.
While in accordance with *he patent:statutes,.the preferred embodiments of the inv~ntion have ~een illustra~ed and describedr it is to be particul æ ly understood that the invention is ~ot lLmited thereto; th~ invention being defined in the appended claim~.

Claims (12)

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A segmented brake disk, characterized by:
a plurality of segments, a gap existing between said segments, said segments having two end portions, a periph-ery, and a width, said segments having a tongue and a swept area, said tongue having an axial width less than said segment width, said tongue extending from one of said segment end portions, said swept area having inherent high thermal expansion and contraction forces, a recess having an axial width less than said segment width, said recess located in said remaining seg-ment end portions, said tongue residing in said recess, said tongue located at said periphery of one of said end portions substantially outside said swept area on said segment, said recess located at said periphery of said remaining end portion substantially outside said swept area on said segment, and at least two separate fastening means for securing each said tongue to each said segment end portion having said recess to form a rigid connection substantially outside said swept area of said segment so that said con-nection is outside said high thermal expansion and contraction forces.

2. A segmented brake disk according to Claim 1, wherein the shape of said recess corresponds to the shape of said tongue.

3. A segmented brake disk according to Claim 1, wherein said disk is made from metal.

4. A segmented brake disk according to Claim 1, wherein said disk is made from a carbon composite material.

5. A segmented brake disk according to Claim 1, wherein said carbon composite material is made from a laminate of a carbon-based material and a carbon cloth.

6. A segmented brake disk according to Claim 1, wherein said disk is a rotor.

7. A segmented brake disk according to Claim 1, wherein said gap between said segments is formed by the combination of said segments having groove portions on each end portion.

8. A segmented brake disk according to Claim 7, wherein said groove portions are located at least closer to said segment end portion than the points where said fastening means secures said tongue to said recess.

9. A segmented brake disk according to Claim 7, wherein the shape of said recess corresponds to the shape of said tongue.

10. A segmented brake disk according to Claim 7, wherein said tongue is located in the central axial portion of said segment and said groove is located in the axial portion of said segment.

11. A segmented brake disk according to Claim 9, wherein said fastening means are rivets or spot welds.

12. A segmented brake disk according to Claim 1, wherein said tongue has a radial surface, a curvilinear portion and an inwardly tapered surface, said tongue radial surface being contiguous with said curvilinear portion and said curvilinear portion being contiguous with said inwardly tapered surface, said recess having a radial portion, a curvi-linear portion, and an inwardly tapered surface, said recess radial surface being contiguous with said curvilinear portion and said curvilinear portion being contiguous with said inwardly tapered surface, and at least two separate fastening means for securing each said tongue to each said segment end por-tion having said recess to form a rigid segmented brake disk.