NZ616958B2 - Piston for an air spring of a heavy-duty vehicle - Google Patents

Abstract

piston for an air spring of a heavy duty vehicle, the piston comprising: a) a sidewall (244) and a central hub (252), the sidewall and the central hub made in one piece and attached to a discrete first bottom plate (250) of the piston; b) a discrete top plate (282) attached to a top portion of the sidewall and a top portion of the central hub, the top plate including a barb (280) around its circumference; c) a second bottom plate (254) formed in the central hub; d) the first bottom plate spaced downwardly from the second bottom plate to define a recess in the piston thereby creating increased piston volume relative to the second bottom plate. sidewall and a top portion of the central hub, the top plate including a barb (280) around its circumference; c) a second bottom plate (254) formed in the central hub; d) the first bottom plate spaced downwardly from the second bottom plate to define a recess in the piston thereby creating increased piston volume relative to the second bottom plate.

Description

WO 201Z/158793 PCI%US2072/038133 AII2 OF A NAVY-DUTY PISTON FOR AN SPRING VEHICLE REFERENCE TO RELATED APPLICATION CROSS- claims the beuefft of U.S. Provisional Patent Application Serial No.

This applicalion 61/486,857, filed May 17, 2011.

BACKGROTJND OF THE INVF,NTION FIELD OF INVENTION Tfi$ The invention relates generally to the art of axle/suspeusion systems for heavy-duty vehicles. the invention to air-ride axle/suspension More particulazly, relates systems fax heavy-duty vehicles, spring to cushion the ride of the vehicle. More which utilize an air specifically, the invention is piston fnr an air spring of a heavy-duty vehicle air-ride directed to a a~clelsuspension system, in the spring piston upper portion is formed in two parts, a which air including top plate and a continuous stepped sidewall. Forming the top plate as a discrete part from flee continuous stepped sidewall allows for more efficient manufachue of the air spring piston. A downwardly extending bottom plate allows for increased piston volume, wldch in turn piston provides a induced spring damping chazacteristics to the air spring. rate, and/or better BACKGROUND ART air-ride trailing and rigid The use of leading azm beam-type axle/suspension systems in the heavy-duty truck and tractor-Trailer industry for been popular many years. Although such systems can be found in widely varying siruchuai ~le/suspension forms, in general tLeir struchue is similar in that each system typically includes a pair of suspension assemblies. In some heavy- WO 2U12l158793 PCTNS2012/U38133 duty vehicles, the suspension assemblies are connected directly to the primary frame of the vehicle.

In other heavy-duty vehicles, the primary frame oP the vehicle supports a subframe, and the suspension assemblies connect duectly to the subframe. For those heavy-duty vehicles that support a subframe, the subframe can be non- movable or movable, the latter being wmmonly referred to as a slider box, slider subframe, slider undercarriage, or secondary slider frazne.

For the piupose of convenience and clarity, reference herein will be made to main members, with the understanding that such reference is by way of example, and that the present invention applies to heavy-duty arzle vehicle /suspension systems suspended from main members of primary frames, movable subframes and non-movable subframes.

Specifically, each suspension assembly of an axle/suspension system includes a longitudinally extending elongated beam. Each beam typically is located adjacent and to below a respective one of a pair of spaced-apart longitudinally extending main members and one or more cross members, which form ttie $ame of the vehicle.

More specifically, each Uea~u is pivotat]y connected at one of its ends to a hanger, which in tum is attached to and depends from a respective one of the main members of the vehicle. An axle extends transversely between and typically is connected by some means to the beams of the pair of suspension assemblies at a selected location from about the mid-point of each beam to the end of the beam opposite from its pivotal connection end. The opposite each beam end of also is connected to an air spring, or its equivalent, which in hun is connected to a respective one of the main members. A heip~t control valve is mounted the hanger or other support struchue and is operatively connected to the beam and to the air spring in order to maintain the ride height of the vehicle.

A brake system and one or more shock absorbers for providing addirional damping to the vehicle axle/suspension system are also included. The beam may extend rearwardly or frontwardly from the pivotal connection relarive to the front of the vehicle, defining what thus are typically referred to as trailing ann or leading arm axle/suspension 2012!158793 PCT/U52U12/U38733 W O systems, respectively. I3owever, for purposes of the description contained herein, it is understood that the term "trailing arm" will encompass beams, which extend either rearwardly or froniwazdly front with respect to the end of the vehicle.

The a~cle/suspension systems of the heavy -duty vehicle act to cuslrion the ride, dampen vi'brarions and stabilize the vehicle. More particulazly, as the vehicle is trave]ing over the road, its wheels encounter road conditions that impart vazious forces, loads, and/or stresses, collectively referred to herein as Forces, to the respective axie on which the wheels aze mounted, and in turn, to the suspension assemblies that are connected to and support the axle.

In order to minunize the detrimentAl affect of these forces on the vehicle as it is operating, the vcle/suspension system is designed to react and/or absorb at least some of fl~em.

These forces include vertical forces caused by vectitical movement of the wheels as they encounter certain road conditions, fore-aft forces caused by acceleration and deceleration of the vetricle, and sid~load and torsional forces associated with hansverse vehicle movement, such as fuming of the vehicle and lane- change maneuvers. In order to addresz such dispazate forces, axle/suspension systems have differing structural requirements. More particularly, it is desirable for an aele/auspension system to be fairly stiffin order to minimize the amount of experienced sway by the vehicle and thus provide what is known in the art as roll stability.

However, it is also desirable for an axle✓suspension system to be relatively flexible to assist in cushioning the vehicle from vertical impacts, and to provide compliance so that the components of the axle/suspension system resist failure, thereby increasing durability of the axle/suspension system. It is also desirable dampen the vibratioas or oscillations that result from such forces. A key component of az1e/suspension system that cushions the ride of the vehicle from vertical impacts is the air spring, while a shock absorber typically provides additional damping to the axle /suspension system.

Z012l158793 PC7'/U52012/038133 W O type utilized in heavy-duty air-aide axle/suspension systems The typical air spring of the The bellows is flexible bellows, a bellows top plate and a piston. components, a includes three main with the bellows or other flexible material, and is sealingly engaged from rubber typically formed air, or "air volume", portion of piston. The volume of pressurized also [o the top the top plate and rate of the air air spring is a major factor in determining the spring contained within the that is some the air contained within the bellows and, in cases, specifically, this volume is spring. More spring, the spring rate of the The lazger the air volume of the air the lower of fhe air spring. piston in the heavy<luty vehicle industry lower spring rate is generally more desirable air spring. A for the vehicle. Typically, the piston either contains for softer ride characteristics because it allows commuoicetion with the bellows and which adds to fhe au~ volume of cavity, which is in a hollow unrestricted communication of air between the piston and the bellows spring by allowing the air communicate the generally hollow cylindrical-shape and does not with voluwes, or the piston has a votume spring. The au the'piston does not contribute to the air of the air whereby bellows volume, with source, air supply tank, is in fluid communicarion an air such as an the air spring volume of control valve of the vehicle. The height control communicarion with the height in fluid and also is the air spring of the axle/suspension system, helps flow into and out of valve, by directing air ride height of the velricle. maintain the desired shaped xnd includes a continuous art au spring piston is generally cylindrically The prior generally flat bottom plate. Atop plate is formed at the top stepped sidewall attached to a generally plate formed with an upwudly extending central hub. The central hub The bottom is of the piston. with one ox more central openings. A fastener is disposed through piat~ formed includes a bottom hub bottom plate in order to attach the piston to the beam of the the openings in the cenRal assembly at its rear end. The top plate, sdewall and bottom plate of the piston define a suspension The top plate of the is formed a circular piston chamber having an interior volwne. piston with wo zmznsx~va apwazdly prohvsion having azound T'he the lowermost end of the bellows to fonn between the bellows with the A bumper attached bumper plate, twin mounted on the piston by fastexier. The bumper extends from the top of the mounting the top and the bellows top in operation order to cuslrion between the plates of the vehicle. other typically from steel, aluminum, spring relarively the piston typically complex on~piece structural manufacture of the piston composite can be desigp, from materials because die lip or integally formed on the particularly, extending which is formed in one with top of plate piston, manufacture of piston from composite be compleac and therefore inefficient, those as is well lmovm to of ordinary skill addition, Uecause plates of the cen4el hub, respectively, genetzlly contained piston is because of spatial 1vnitalions between of of velricic. vehicles of khe air piston for heavy invention, overcomes the with azt air piston providing problems an air piston upper portion formed in hvo that assembled. air piston for -duty of present invention includes downwardly extending that plate foi an increased piston volume while utilizing same mount configuration hardwaze eacisting in prior art downwardly extendvag piston bottom plate allows for an volume without for increased piston the redesigned additional mounting brackets and without changing spatial measurements betwaen the and beam main member. Therefore, the PCT/U52U72/038133 a lip or barb its circumference. cooperates extending barb aix s}rring an airtight seal and piston. is to a mounting which is in top plate a upwardly surface bwnper plate plate and serves as a cushion between piston plate during contact two The piston is formed fiber reinforced plastic rigid material. air has Because prior art a integral compiicazed. More barb is in one piece upwazdly grokusion, in tum integrally piece the the the materials can quite in the art. In the bottom piston and the flat, the volwne in the limited beam generally the the suspension assembly main the the member -duty The spring present associated prior spring designs by spring parts are Moreover, the spring heavy velricles the a piston bottom allows still the and designs. This need the the WO 2012/158793 PCTlUS2012/038133 heary-duty vehicles of the present invention provides for more af&cient and air spring piston for that reduces manufacturing cosh and provides for an increased piston chamber simple manufacture chamber piston-to-beam mounting hardwaze, whereby the increased piston volume using existing better spring rate and/or damping chazacteristics to tUe air spring. volume provides a reduced SUMMARY OF THE INVENTION heavy- include a an air spring of a Objectives of the present invention providing piston for efficient and simple to manufacture and that seduces manufacturing costs. duty vehicle that is more objective of the present invention is to provide a piston for an air spring of a A further provides increased piston cbaznber volume using e~cisting piston-to-beam heavy-duty vehicle that mounting hardware. provide a piston air spring of a another objective of We present invention is to foX an rate and/or damping velricle that provides a reduced spring provides improved heavy-duty characteristics to the air spring. and advantages are obtained by the piston for an air spring of a heavy-duty These objectives which includes a sidewall and a central hub. The sidewall and the the present invention, vacuole of plate. A discrete top plate is attached to a top portion of attached to a fast bottom ce~rtral hub are around of the central hub, said top plate including a barb its sidewall and a top portion circumference. obtained by the piston an air spring of a heavy- objectives and advantages are also for These sidewall and a central hub. sidewall and present invention, which includes a 7'he duty vehicle of the plate. A discrete top plate is attached to a top portion of attanited to a fvst bottom the cenh'al hub cenha] the top plate e~ctending outwardly beyond the top the aidewatl and a top portion of the hub, portion of the sidewall.

WO 20121158793 DESCRIPTION OF TfIC SEVERAL VIEWS OF THE DRAWINGS BRIEF in which embodiment of the present invention, illustrative of the best mode The preferred set fortU description and is have contemplated applying fhe principles, is in the following applicants pointed out set the appended the drawings, and is paztieularly and disrinctly aad forth in shown in claims. heavy-duty trailer a~cleJsuspension system FIG. ] is a top rear perspective view of a each one of the pair of air springs mounted on a incozporaNng a pair of prior art air springs, with the a~cle/suspension system; respective one of the suspension assemblies of perspective view of a prior art air spring in section, showing the circular is a piston top extending protrusion and lip or barb integrally formed as one-piece with the upwazdly- the generally flat piston botkom plate and flat central hub bottom plate; plate, and showing front perspective view of the beam of the driver side suspension assembly is a attached to tLe plate beam for and showing a beatn mounting pedestal top of the shown in assembly; mounting tUe air spring on the suspension perspective view of a prior art air spring Foz a truck axle/suspension 2B is a sectional F1G. extendmg protrusion and lip or barb integrally foamed as one-piece showing the upwardly- system, flat bottom plate; and showing the generally fragmentary secrional perspective view of another prior azt air spring for a is a showing the air spring piston mounted on a conventional beam mounting heavy-duty trailer, beam of the axleJsuspension system; pedestal and sectional view of a air 3 is a fragnentary perspeclive prefemd embodiment spring P1G. of the present invention incorporated into an air spring for axle/suspension system of a piston conventional beam pedestal beam of heavy-duty ve]vcle, shown mounted on a mounting and an system; axle/suspension 2U72l158793 perspective view embodiment the preferred air spring present invention shown in FIG. a perspective sectional view preferred embodiment air spring invenrion numerals refer similaz parts throughout the drawings.

DESCRIPTION THE PREFERRED EMBODIMENT the which order better understand air spring piston for heavy-duty present a trailing arm overslung air the -ride aaclelsuspension system that incorporates prior heavy vehicle 4ailer 124, is indicated generally shown and now will be described in detail below. should axle/suspension system typically -apart shown) longitudinally-extending spaced main -duty vehicle, various fraznes used heavy generally represcntaflve types vehicles, including primary support subfrarue primary frames and/or floor structures do frames that do support primary fumes and/or structures do support the sabframe. For can be movable oz the latter being commonly to box. Because axle/suspension system geaierally suspension 14, for sakc will be clazity only one the suspension assemblies below. is connected to 76 Suspension assembly 14 pivotally hanger via trailing arm oveislung beazn having generally upside integrally 18. More speciScally, -down formed beam pair sidewalls 66 plate 65, with the open beam -shzpe with portion the facing downwazdly. A bottom plate 63() extends between and is attached generally the suitable lowermost ends sidewalls by any means such as welding to complete the structure of is a piston of the of tl~e piston the is of shown in present Similar to in the Tn to environment invention is utilized, vehicles of beam-type a art -duty air spring at ]0, is in It be noted that 10 is mounted on a pair of members (not of a heavy which is of for -duty a and IS not that x floor fliat a subframe, subframe movable, referred as a s]ider non- ]0 includes an identical pair of assemblies described of of 18 is formed a and a top of U a of of 66 wo zmznsx~v3 PCT/U520]2/113H333 18. azm beam IS includes 20 having assembly 22, includes bolts washers are well lmown the azt, to facilitate coanection of the to hanger 16. IS also includes rear 26, which welded to hansversely- rigidly Suspension lA the top end of shock absorber mounted an 40 on 17 of via manner inboardly and lmown art. The of shock absorber 40 well the to skill shown) in well known to those having the art. ror the of brake chamber 30 brake system mounted on suspension assembly system 0 is designed fo As above, arle/suspension forces that on the is operating. More perticulazly, is for as /suspension system 10 to be rigid resist roll thus provide roll for stiffin to vehicle. This is typically using beam which rigid, and also rigidly attached accomplished to It is also desirnble, however, for axle/suspension system 10 to be to assist cushioning velilcle impacts shown) and provide so 1Lat /suspension system achieved flexibility typically through connection of beam 18 to assembly Air 124 spring shock absorber 40 in passengers. cusluouing ride for cexgo specifically, 124 will be in described detail. is incorpornted into an Air 124 /suspension air axle/suspeusion system. Air spring system 10, or similar 124 includes a bellows 141, The bellows a bellows top and a piston 142. of 141 is sealingly with bellows top plate 143 in a manner in air spring mounting (FIG.

Trailing averslung a front end a beam bushing pivot which a bushing, and as in pivotal beam Beam a end is or attached a e~Rending a~cle 32. otherwise assembly also includes a wing hanger 16 a mounting bracket 19 a extending fastener 15, in a in bottom end is mounted beam 1 B (the mount not a manner in sake relative 28 including a is completeness, a shown prior art menrioned absorb act it desirable aide vehicle it forces and stability or order the 7 8, is is by axle 32. flexible in the (not from vertical to compliauce the axle resists failure. Such is pivotal hanger 16 with bushing 22. and also assist prior art au spring shown in now More typically axle/suspension system such as spring axle other -ride plate 143 end engaged well known art. An plate 4A WO 2U12/7587Y3 PCT/US2012/tl38133 surface of top plate 143 by fasteners 45 which also used to typically mounted on ffie top are of air spring 124 to a respective one of the main members (not shown) of the mount the top portion one of Alternatively, bellows top plate 143 could also be mounted directly on a tespecdve vehicle. is cylindrical-sLaped and members (not shown) of the velvcle. Piston 142 generally the main sidewal] 144 attached to a generally flat bottom plate 150 includes continuous generally stepped piece with a top plate 182. Bottom plate 1 SO is formed with an integrally formed in one hub 152 and is attached to sidewall 144 in a well lmown manner. upwardly-extending cenhal bottom plate 154 formed with a central opening 153. A fastener I51 is Central hub 152 includes a 153 in order to attach pisWn 142 to beam mounting pedestal 130 (PIG. disposed through opening spring mounting art. a that is well lmown in the beam-air 2A), of type beam mounting pedestal generally flat additional reference to , 130 includes a With plate 65 beam mounting and seating on beam top of rear end 26. Beam base 131 for contacting upwazdly extending column 132, wMch contacts central hub bottom pedestal 130 also includes an spring 124. Column 132 is formed with a cenhal generally verhically- 154 of piston 142 of air plate which fastener 151 is disposed. A lock nut (not shown) is threaded extending opening J 33, t}uough 2 51 in order to attach piston 142 to bram mounting pedestal 130, A onto a threaded end of fastener webs 135 are located on column 132 and extend ouhvardly firom the colwnn pair of strengthening pedestal opening 136 is formed in base 131. Opening 136 receives a fastener on flat base 131. An attaching pedestal 130 to beam top plate 65 at hewn reaz eud 26. Beam mounting (not shown) for material such as steel, aluminum or composite is typically forrned from a rigid pedestal 130 art, may may not include strengthening ]35. material, as is well known in the and or webs Wp plate 182, sidewall 144 and bottom plate I50 of continued reference to With chamber 194. Top plaze 182 of piston 142 is formed with a cirwlar 142 define a piston piston around Bazb protrusion 183 having a lip or barb 180 its circumference. 180 ❑pwardly extending cooperates with the bottom terminal bellok~s 141 end of to fomt an airtight seal between ffie bellows the bazi~ around the protrusion 183 and circumference of of piston 142, as is known to those of well ordinary skill in the art. Bellows 141, top plate 143 and piston top plate 182 define a bellows chamber 198. A bumper 181 is rigidly attached to a bumper mounting plate 186 means by generally well lrnown in the art Bumper mounting plate 186 is in turn mounted plate on piston top 182 by a fastener 184. Bumper 181 e~ctends upwardly from the top surface of bwnper mounting plate 186. cushion plate Bumper I81 serves es a between piston top I82 and the underside of bellows top plate 143 in order to prevent the plates from damaging one another in the event that the piston top plate of bellows top plate contact one and the underside the another during operation of the vehicle.

Manufachue of piston 142 from composite materials can be quite complicated and therefore inefficient, as is well lmown to those of ordinary skill in the art.

Piston top plate 182 is formed with a pair of openings 185, wMch the volume allow of piston chamber 199 and the volume of bellows chamber 198 to cottununicate with one another. More allow Iluid or air to pass between particularly, openings 185 piston chamber 199 and bellows 198 operation of the vehicle.

I S chamber during now to , a prior art air spring for a truck axle Turuins /suspension system is shown spring 324 generally includes a generally at 324. As bellows 341, a bellows chaznber 389, a plate 343, a piston chamber 399 and a piston 342. Piston 342 bellows top is formed with a generally plate an open top plate 382 having an flat bottom 354 and upwardly-extending prohusion 383 barb 380. Piston 342 includes a hollow piston fornied with a lip or chamber 399, which is in fluid with be]lows 341 and allows unrestricted communication of air between the communication piston cavity and the bellows. Because prior art air spring piston 342 hes an integral one-piece shuctural design, manufacture of the piston from composite materials can be complicated. More particularly, 380 is integrally in one-piece on because lip formed upwardly-extending protrusion 383, WO 2U12l158793 PC1'/US2012/038133 manufacture of the piston from composite materials can be quite complicated and therefore inefficient, as is well t~ovm to those of ordinary skill in the art. , another example of a prior art Turning now to air spring for an a~cle/suspension is shoxm generally at 424. Air spring 424 generally includes a system bellows 441, a bellows top plate 443 and a piston 442. Piston 442 is mounted on suspension assembly fastener 451 S Beam 18 by conventional beam mounting pedestal 130, described disposed tluough in detail above. Air spring 424 is representative of an air spring configuration different from prior art av springs 12A and 324, whereby piston 442 does not conhibute to the air volume of the air spring and which still utilizes conventional beam mounting pedestal 130 in the field, i.e. no piston chamber, a bellows only chamber 489. above, because prior art air spring pistons 142,342 As set forth have a relatively complex one-piece shvctural design, manufactare of the pistons from a integral composite material can be complicated. More pazticularly, because lip oc barb 180,380 is integrally formed on upwazdiy extending prohvsion 7 83,382, respectively, which in tw-n is integrally formed with top plate 182 of plate of piston 142 and top 382 piston 342, respectively, manufacture of the piston from composite complex materials can be quite and therefore inefficient as is Imown to those of ordinary skill in the of the present art. The air spring piston invenrion overcomes the problems with prior associated art 142,342, and will now be described in detail below. air spring pistons A preferred embodiment air spring piston of the present invention is shown generally at 242 in FIGS. 3-5, with showing the air spring piston of the present invention incorporated into an 224 axle/suspension system (not shown), and now will au' spring of an be described iu detail below. accordance with one of the primary features of the present In invention, air spring 224 includes bellows 241, a bellows top plate 243 and preferred a embodiment air spring piston 242 of the present invention. The top end of bellows 241 is sealingly engaged with bellows top plate 243 WO 2012l15St7Y3 PCTlUS2012/U3N133 known in the art. An air spring mounting plate (not on the in a manner well shown) is mounted top fasteners (not shown) which are also used mount top portion of air surface of top plate 243 by to the respective one of the main members (not of the vehicle frame. spring 224 to a shown) top plate 243 could also be mounted directly on a respective one of the main Alternatively, bellows members (not shown) of the vehicle. feature 224 In accordance with another important of the present invention, air spring generally cylindrical- and contiguous includes air spring piston ?A2, which is shaped includes a 24A and a central hub 252, each attached to a generally downwazdly gexierally stepped sidewall plate 250 and a discrete top plate 282. More particularly, the lower end of extending flat bottom formed with a groove 246, which receives a correspondingly shaped outer tongue sidewall 244 is plate 250. The lower end of central hub 252 also is forrned with a groove 247 formed on bottom inner tongue 249 formed on plate 250. In thrs receives a correspondingly shaped bottom 248, which grooves 246,248 and inner and outer tongues 247, 249, respectively, allow bottom plate manner, be friction welded to piston central hub 252 and piston sidewai1244. 250 to includes an integally foirumed generally flat recessed bottom plate 254 Central hub 252 opening 253, snd wlueh is recessed relative to bottom plate 250. A fastener formed with a central opening 253 in order to attach piston 242 to prior ari beam mounting 251 is disposed through above. Beam mounting pedestal 130 includes generally flat base 131 for pedestal 130 described suspension assembly. 130 the beam top plate of its respective Beam mounting pedestal contacting ccnkal 254 includes upwardly extending colwnn 132, which contacts hub bottom plate ( also fluough disposed. 132 is foamed with central opening 133, which fastener 251 is Lock 3). Column 151 in order to to tlueaded onto a Uueaded end of fastener attach piston 142 beam nut 134 is Strengthening webs 135 {not shown in are located on column 132 mounting pedestal 130. the column on flat base 131. Opening 136 in is and e~ctend outwudly from (not shown WO 21172/i5R7)3 PCTlUS2UI2/038133 formed in pedestal base 131. Base opening 136 receives fastener (not shown In for 130 to beazn top plate 65 at beam rear end attaching pedestal 26. Beam mommting pedestal 130 is formed from a rigid material aucb as steel, aluminum or typically composite material, as is well in the and may or may not include strengthening webs 135. known art, Top plate 282 is formed with a plurality of openings 295. Openings 295 4 and 5) (FIGS. (not shown) align with openings fozmed in the top portion of piston central hub 252. A fastener (not openings aligned shown) is disposed through 295 and openings (not shown) in the top portion of central bub 232 in order to attach top plate 282 to the piston central hub and piston sidewall 244. 244, central hub bottom plate 254, and Top plate 282, sidewall piston bottom plate 250 define a chaznber 299. Because piston bottom plate 250 is generally downwardly extending, piston piston volume is greater than prior art piston chamber 199 volume, chamber 299 shown and described Moreover, because piston bottom plaze 250 is generally dovmwazdly recess above. Mending, a 297 farmed in piston 242 by a portion of central hub recessed bottom plate 254 and a portion of plate also with bottom plate 250. Top 282 is formed a eirculaz upwardly extending protrusion 283 circumference. formed with s lip or barb 280 aromid its Barb 280 cooperates with the bottom bellows 241 to form an airtight seal between the terniinal end of bellows and the barb, as is well of ordinary sidll in the art. It should be understood top known to those that place 282 could be lazger diameter than cenffal bub 252 such that the outer edge of ffie plate formed having a top would barb lip 280, without changing the overall concept or operation of the invention. form or present Bellows 241, top plate 243 and top plate 282 define a bellows chamber 298. A bumper 281 or other is rigidly attached to top plate 282 by adhesive means generally well known in the art. upwardly top surface of plate extends from the top 282. Bumper 28] serves as a Bumper 28I plate 282 and bellows top plate in order to keep cushion between top 243 the plates from damaging the event that the piston top plate and the bellows [op one another in plate contact one another PCT/US2012l1138133 during operation of the vehicle. A plurality of shengthening webs 259 extend between piston sidewal1244 and piston central hub 253 and between the walls of the central hub itself in order to strengthen piston 242.

Top plate 282 also is formed with a pair of openings 285, which the volume piston allow of chamber and the volwne of 298 to 299 bellows chamber communicate with one another. More openings 285 allow fluid pass between pazticulady, or air to piston and bellows chamber 299 chamber 298 dining operation of the vehicle. This communication betwcen piston chamUec 299 and 2981hrougli bellows chamber openings 285 provides viscous damping to air spring 224 as described shown in U.S. PaYeut Application No. 13/228,908, owned by and the assignee of the present application.

Improved air spring piston 242 for heavy-duTy vehicles of We present invention overcomes with prior ert pistons the problems associated air spring 142,342 by providing an air spring piston upper portion, w3ilch is formed in two separate parts that are assembled, This hvo-part assembly that provides a top plate 282 is easier to manufacture than prior art piston top plates that aze formed integrally with the rest of the piston. Moreover, au spring piston 242 I S for heavy-duty vehicles of the present invention includea downwardly extending piston bottom plate 250 that allows for an increased piston chaznber 299 volume while still utilizing the same air spring-to-beam mount configuration existing in prior ert designs. More particulazly, downwazdly extending piston bottom central hub plate 250 and recessed bottom plate 2S4 allow for an increased piston volume while for or utilizing prior art pedestal 13U, without the need new additional brackets mounting and without changing the spatial measurements between beam 18 of the 10 axle/suspension system and vehicle. the main member of the Therefore, preferred embodiment air spring piston 242 for heavy- present invention provides for more duty vehicles of the efficient and simple manufachu'e that reduces maaufaoturing costs and provides for greater piston chamber 299 volume using existing R'O 2(112/156793 /US2U72/038133 piston-to-beam mounting hardware, whereby the increased piston volume provides a reduced spring rate and/or better damping chazacteristics to the air spring. 7t is contemplated that preferred embodiment air spring piston 242 of the present invention could be utilized on bucks tractor-trailers having one or mole than one axle the without changing concept or operafion of the present overall invention. It is fiuther wntemplated that preferred embodiment air spring piston 242 of the present invention could be utilized on vehicles having frames or subframes which are moveable or non-movable without changing the overall concept of the It is yet even further present invention. contemplated that preferred embodiment air spring piston 242 of the present invention could be utilized on all types of air-ride leading and/or trailing arm beam-type axle/suspension system designs Imown to those skilled in the art without changing the overall conceQt or operefion of the present invention. For example, the present invention finds that made application with beams or arms are of materials oihes tLan steel, sueki as aluminum, other composites, combinations metals, metal alloys, and/or thereof. It is also contemplated that preferred the present embodiment au spring piston 242 of invenrion could be utilized on a~cle/suspension having either an overslung/top-mount configuration or an systems underslung/bottom-mount configuration, v.ithout changing the overall concept or operation of the present invention. The present invention also Bends appficarion in beams or azms with different designs and/or configurations than that shovm above, such as solid beams, shell-type beams, truss structures, intersecting plates, spring beams and parallel plates. The present invention also finds application in shvewres such as spring interrnediary seats. It is also contemplated that preferred embodiment 242 present invention spring piston of the could be urilized is conjunction with otter types of air- ride rigid beam-type arle/suspension systems such those using as U-bolts, U-bolt brackets/ale seats and the like, without changing the overall concept or operation of the present invenrion. It is also contemplated that preferred embodvnent air spring piston 242 of tl~e present invention could be wo zu~2nsa~vs PCTlUS2012/U3t1133 formed from various materials, including but not limited to composites, metal and the like, without changing the overall or concept operation of the present invention. It is yet even further contemplated that preferred embodiment air spring piston 242 of the present invention could be utilized with fewer than two or more than two openings 285 such as three, four oz even five or more openings without changing the overall concept for operation of the present invention. It is also contemplated that preferred embodiment air spring piston 242 of the present invention could be utili2ed with any viscous fluid, such as air or hydraulic fluid, without changing the overa!] concept of the present invention. It is fiuther contemplated that preferred embodiment air spring piston 242 of the present invention could be utilized in combination with prior azt shock absorbers and other similar devices and the like, without changing the overall concept of the present invention. It is contemplated that top plate 282 of air spring piston 242 of the present invention could be utilized either with or without bumper 281, without changing the overall concept or operation of the present invention. It is also contemplated that top plate 282 of air spring 242 the of present could invenrion be utilized either with or without openings 285, without changing the overall concept or operation of the present It invention. is even fiutLer contemplated that preferzed embodiment air spring piston 242 of the present invention could be utilized in conjuncfion with prior art pedestal 130 or other similaz pedestals or beazn mounting shuctures, without changing the overall concept or operalion of the present invention. It is yet even further contemplated that bottom plate 250 of air spring piston 242 could be adhesively bonded to, mechanically fastened to, attached via other means well known in the art to, or even formed as a part of, the air spring piston, without changing the overall concept or operation of the present invention. It is also understood that preferred embodiment air spring piston 242 of the present invention could be utilized with at] types of air springs without changing overall concept or operation of the present invention. wo 2uiznss~va PCTNS20]2/038133 the piston for an au Accordingly, spring of a heavy-duty vehicle of the present invention is simpiified, provides effective, safe, an inexpensive and efficient structure and method which achieves all the enumerated objectives, provides for eliminating difficulries encountered with prior pistons, and solves problems and obtains new results in the art art.

In the foregoing description, certain tenors have been used for brevity, clearness and understanding; bnt no unnecessary limitations aze to be implied therefrom beyond the requirements of We prior art, because such terms are used for descriptive purposes and are intended broadly w be construed. descriprion and the Moreover, the illustration of invenrion is by way of and the example, scope of the invenrion is not lunited to the enact details shown or described.

Having now described the feahn~es, discoveries and principles of the invention, the manner in which the pisron for an air spring of a heavy-duty vehicle is used and installed, the chazacterisdcs of the construction, arrangement and method steps, and the advantageous, new and useful results useful obtained; the new and sWchues, devices, elements, arrangements, process, parts and combinations are set forth in appended claims.

WHAT IS

Claims (5)

1. CLAIMED IS: 1. A piston for an air spring of a heavy duty vehicle, said piston comprising: a) a sidewall and a central hub, said sidewail and said central hub made in one piece and attached to a discrete first bottom plate of the piston; b) a discrete top plate attached to a top portion of said sidewall and a top portion of said central hub, said top plate including a barb around its circumference; c) a second bottom plate formed in said central hub; d) said first bottom plate spaced downwardly from said second bottom plate to define a recess in said piston thereby creating increased piston volume relative to the second bottom plate.
2. 2. The piston for an air spring of a heavy-duty vehicle of Claim 1, wherein said top plate is formed with at least one opening, said at least one opening communicating with an interior chamber of said piston and an interior chamber of a bellows of said air spring.
3. 3. The piston for an air spring of aheavy-duty vehicle of Clain 1, further comprising a bumper disposed on said top plate.
4. 4. The piston for an air spring of a heavy-duty vehicle of Claim 1, further comprising said first bottom plate including a pair of concentrically spaced inner and outer tongues extending generally upwazdly and aligned with said central hub said sidewall.
5. 5. The piston for an air spring of a heavy-duty vehicle of Claim 4, further comprising a first groove formed in a bottom surface of said sidewal] and a second groove formed in a bottom surface of said central hub, said first groove communicating with said outer tongue of said first bottom plate and said second groove communicating with said inner tongue of said first bottom plate. The piston an of -duty of Claim wherein said first said and said hub. 7. The piston for Claim a webs said and hub. an of aheavy spring Claim fizrther 9. The air Claim 8, wherein said a beam of a assembly of said vehicle. for air to air to -duty piston for an air of 10, to a of bellows. an air a -duty Claim 11, to of -duty 13. piston for air spring Claim 11, piston 6. for spring a heavy vehicle 1, bottom plate is friction welded to sidewali central an air spring of a heavy vehicle of 1, further -duty comprising plurality of formed between sidewall said central 8. piston for The air -duty vehicle of 1, comprising a piston mounting pedestal attached to said second bottom plate. piston for an spring of a heavy-duty vehicle of piston mounting pedestal is attached to suspension heavy duty 10. The piston an spring a heavy duty vehicle Claim 1, said piston operatively attached a of said spring, said bellows turn bellows operatively attached a frame of said heavy vehicle. 11. The spring a heavy-duty vehicle of Claim further comprising a bellows top plate attached top portion said 12. The piston for spring of heavy vehicle of wherein said top plate attached the frame said heavy bellows vehicle. an of heavy The a -duty vehicle of said being formed from plastic. 14. The piston for an air spring of a heavy-duty vehicle of Claim 1, wherein attachment portion said of said top plate said top of said sidewall and said top portion of said central hub is removable. 15. A piston for an air spring of a heavy duty vehicle, said piston comprising: a) a sidewall and a central hub, said sidewall and said central hub made in one and attached discrete first bottom plate the piston; piece to a of a Yop portion of said and a top portion of said top said portion said form a top portion hub; from said define a in said increased piston volume plate sidewall b) discrete top attached to a said central hub, plate extending outwardly beyond top of sidewall to barb around the sidewall circumference. c) a plate second bottom formed in said central d) said first bottom plate spaced downwardly second bottom plate to recess piston thereby creating relative to the second bottom plate. } 14 PRIOR ART WO