CA2201579A1

CA2201579A1 - Bus drive axle

Info

Publication number: CA2201579A1
Application number: CA002201579A
Authority: CA
Inventors: Kraig J. Schlosser; James H. Sheets
Original assignee: Dana Inc
Current assignee: Individual
Priority date: 1996-04-03
Filing date: 1997-04-02
Publication date: 1997-10-03
Also published as: GB9705950D0; JPH1044795A; BR9701618A; DE19713651A1; KR970070644A

Abstract

Twin motor automotive vehicle, especially a bus, having first and second electric motors disposed on opposite sides of a longitudinal center line of the vehicle, a drive axle assembly having transversely spaced first and second gear housings, each having therein an input gear driven by one of the drive shafts, and an output gear; axially aligned axle shafts extending outwardly from the respective gear housings to respective sides of the vehicle; tubular axle housings extending transversely outwardly from respective gear housings to respective sides of the vehicle; a transversely extending tubular stiffening member extending from one gear housing to the other and joined to each; and first and second wheel assemblies rotatably mounted on respective first and second tubular axle housings and driven by respective axle shafts. The drive axle assembly is preferably a rear axle assembly. The drive axle assembly is a full floating drive axle assembly in which vehicle weight loads are borne entirely by stationary members, i.e., the gear housings and the axle housings, so that weight load stresses are not transmitted to the axle shafts. The gear housings may contain either conventional differential gears or simply beveled pinion gears formed on an input shaft driven by a drive shaft, and a beveled ring gear which drives an axle shaft. In either case, the gear housings are disposed toward sides of the bus so that the bus may have a low floor which is lower than the axle shafts, thereby facilitating the boarding and the discharging of passengers, especially those having orthopedic limitations.

Description

~ 2201579 B~JS Dl~ A?~LE
Techrlical Field ~is invention relates to auto~notive vehicles and trive sy~ems therefor, especiall~
to a twin-drive arld a~le syste~ ~rhiGh is especially suitable for llse on buses.

13n~ tound,Art Tw~-drive buses were in operation orl city streets ill the United States durihg the early days of bus transport~tion and were ~escribed in patents iss1led d~ing that periot The twin-dlive bus ~f~ered several advar~tages over th~ more widely ~sed single r~oto~
buses olCthat era For example, the passer~ger compartmel~t o~a t~in-~rive bus extended the e~tire iength of the bus since t~ere was no hood, as was the case in single-motor buses c~ the era. This affo~ded ~ l~rger pasSenger-carryillg capacity fo~ a given lerlgth of bus.
fi~ther advallta~e was that sm~ller ~otors could be used A still filrthe~ advantage was tl~at no ~ el.Lial w~s required since ¢~ch motor drove th~ wheel (o~ w~cels) on o~ly o~e side o~the bus, and the two ~otors and the respective d~Ive shaf'cs were cap~ble of ope~ating at diffle~erlt sp¢eds.
Ea~lier twi~-motv~ buses had ce~tain disadvantages. ~mo~g these ~e~c the fo~lovving: a "semi-floatin~" suspemsiorl ~hich plaGed weight load on rear a~le shafts and drive train$, resulting in u~.cvell and rapid gear ~esr; a wor~ gea~ which is not

2 o satisf~Gtoly at ~ode~ate or Wgh vel~cle speeds, for t~n.C~ittin~ torque ~om a drive sha~
to a rear axle sha~t; and pollution ~hich wo~l~ be urlacceptable by today's standard~.
In spite o~t~e advantages, the twin-~otor bus fiell i~to di~use. F3uses ,ge1le~ally have had a si~le eng~e loc~ted i~ the ~ear of the ~us, wllich drives the ~ear ~heels through a conventional di~llti~l. P.~ne~ p~ovidi~g higher power coIltributcd to use of 2 5 a ~ gle en~ne, but such buses ~ave ~ad high floo~, even a*er the adv~nt o~the autor~atic tr~n.qmi.i,qion T~is le~ds to passenger inconverl~ence and discomfort whe~ boarding and leaving the bus, eVeh fior an average p~sengP,r having rlo physic~l impairments, and maJses ~xtre~e~ diffiGult the design arld implementation o~ a system fior ~oadirl~ and dischargi~g P~ er~ having physical disabilities.

3 0 R~cently. there has be~n interest ill a low~floQr ~lect~ic h~brid ~E~V) bus having good fil~l eGonoh~y and low pollu~ion, and generally ~aving the adva~tages o~earlier twin-moto~ b~ses without the di~advantag~s.

22n 1 ~ 7 9 , --S-lmm~rv of the In~ention Based upo~ the ~oregoing, it is an object of the invention to his invention accordi~g to pro~ride an automotive v~hicle ha~ing the ad vantages of the ~Win-rnotO~ d~ive ar~ange~nent and overco~ing the deficiencies of the prior art. Tb.e inVehtion iS therefo~e d~rected to a vehiGle compriSing first ~nd second motors disposed on opposite sides of a longit~ dinal ce~ter line of the ~ehicle. The IllO~O~S illclude first arld second drive sha~s ext~nfljn,~ longitu~ina.lly ~o~ and driv~n by said first and seGo~d motors respectively. The vehicle fil~ther includes a fiull lloat~n~ drive axle assembly which comprises first aIId second transve~sely spa~cd gear ~qemhljes, each Gomp~ising a gear ho-lsing having aII input gear in driven relatiollship with one ofthe drive shaf'cs, and an output gear. Pirst and scco~d a~ially alig;tled ~d transversely e7ftp-n~ljng a2~le shafts are dri~ gly connected ~o respective output gears in tlle respeGtiYe fi~st a~d second gear housings. Al0~2g with thc drive sha~s, first and seco~d Statiohary tubul~ axle housi~gs are joined to respective first and second gear ~ousillgs and extend transversely outwardly thclt;rl~)nl. ~ stationary~horizontal member is sec~red to the gear housings and e~tends ~nsversely firom the flrst gear housing to the second gear housing ~t a lower elev~ion than the ~sear housin,~s Fi~st alld secolld wheel ~ssernblies are rotatably mounted on the respective first a~d second tubular axle l~ou~ings ~t d~hgly co~nected to respectiYe ~rst and second a~le sh~f'cs tocomplet~ the d~ve s~stem.
O In a seco~d aspect, the inverltio~ provides a drive ~heel and axle assembly which comprises first and second transversely spaced gear assernblies. ~ach gea.r assembly compnses a gcar housillg havi~g ah input gear adapted to be driven by an e~tern~l lor~ihl~1~AIly exten~ing d~ive shaPt, and an output ge~r in ~eshing enga~emeht with th~
input gear and being adapt~d to dri~e an axle shaf'c. ~irst and seGond axial~y ali~3ned and 2 5 transversely ~xtellding axle shafts are d~ivingly corlnectç~i to respeGtive outl~ut gears, and first ahd second stationary tubular axle llousings are joilled to respective fust a~d seco~d gea~ housil~gs and extend transve~sely outwardly there~rom. A stationaly hori~:ontal stiff~ing member is secured to the first and second ge~ housings ~nd e7~tends transve~sely t~erebet~eell. The ~lirrr~ g m~mber is po~itioned at a lo~er el~vation than the gear 3 ~ housings. First ~nd se~ond whe~l assemblies are rotatably m~ ted orl respectiYe first and seGond axle ho.usihgs ~nd drivingl~r connecte~ to ~espectiYe ffrst and second axle shafcs.
The l~r~fe~ d autonlotive ~ehicle is a passenger bu~. ~he present inventio . ~ 2 2 2 0 ~ ~ 7 ~

provides several advantages over presently known passenger buses. First, a bus accor~
to the present invention can ~ave a lowe~ floo~ than a conve~tional bus. This ma~ces it easier to loa.d a~d disGharge o~thopedically harldicapped p~ssengers, and also provides greater co~nfiort to non-h~nt1ir.~rped passengers when boarding or leavin~ the bus.
Se~oIId, th¢ bus uses a fi~ll floati~g drive axle assembly in which all vehicle wei~t or load is borne by stationaIy housing members~ so that the dri~re axles do not h~ve to bear vehicle ~iveight or load. Othe~ advahtages will appear ~om the ~raw~rlgs alld Sro~ the specification wbich follovvs.

Bli~f Desc~iption of the D~a~in~s Fig. 1 is a top view of a dnYe a7sle assenlbl~ a~d t~in drive trains theref~
according to a prefeïTed emloodirnellt of t~is in~re~tion Fig. 2 is an e~d v~ew~ as seen ~om the ~ear of t~ vehicle, of the embodiment sho~ in Fig. 1.
Fig. 3 is a~ enlarged s~ctional view o~a ~ rt;--~ial case housing a diIrel~l.Lial r~e~h~n;~m which ~aybe used in a~ehicle ofthis invention.
Fig. 4 is an e~l~ged horizontal sectiona~ view, t~;en along line 4-4 of Fig. 2, showing an alterna~ive ~ear housin~ d gea~s thereirl which may replace a conventiollal dif~re~tial gear~ and an axle shaPc and housi~g therefore e~ ing tr~nsversely outwardly 2 0 fro~ the gear housing to one side of the vehicle.

;I)escr~ption of the Prefe~red ~mbodiments T~is invention ~ill be dcscribed i~ detail lvith refe~ence to the },re~ d embodiments thereof~ as illus~ated in the ~ccompa~ying drawi~s.
2 5 The prefe~red automotive vehi~le of this illVerltiOh iS a passenger bus, especially a passen~er bus fio~ city transit use, ~aving motors located on opposite sides of a lon~h-~lin~l center line o~the vehicle. The ~fe,~d motors are electnc motors, espeGially alternating current (~C) electriG indllGtion motors. Thc bus may be an electriG hybrid (~
V) bus in vvhich thc motors are driven by generators which are powe~ed by one or mo~e 3 0 internal combustion eng~nes or tl ~bines. Alte~n~tiYely, the ~oto~s m~y be po~ve~ed by electric storage batteries, ~hich can be ~echarged when the vehicle is not in senicc. A
vehicle r~ay ev~n be a t~aclcless t~olley i~ which t~e eleG~ic motors receive power directly ~ .. , ~ 3 ~ ~201!57~

firor~ external overhead ~ires.
l~his description will be wit~ pal tiGular refe~ence to ~ vehicle having a single rear axle and t~o wheel asse~blies, OnE at each side o~the ve~icle. Each wbeel assembly ~ll typiGa~ly include two wheels7 an in~er wheel a~d a~ outer whe~l. ~ccording to a pre~e~red e~bo-lim~llt the drive wheels are rcar wheels, and so that the dri~re a~le assembly herein is a ~ear a7~1e assenlbly. Althou~ this disclosure is with referer~ce to a vehiGle h~ving a sing~¢
rea~ axle assembly, it w~ll be apparerlt that the invention can ~Iso be applled to ~ vehicle hav~ng t~dem drive a~les (us~ally rear axles). In that case, it ~ay be advalltageous ~o provide fou~ motors, so tllat each w~eel assembly has its ow~ motor and its ovvn drive 1 0 train.
Re~erring now to ~i~s 1 and 2~ an auto~otive vehicle drive system of the p~ese3lt i~ve~tion has fi~t a~d second AC electric induction ~otors 10, which a~e equidistantiy sitll~te~l on opposite sides (i.e., a lef'~ side ahd a rig~t side) of a longih7~in~11y extending vehicle ce~er line A. These electriG motors may ~e powe~ed ~s described above.
Alternatively but ~ot preferably7 the electric motors 10 may be ~eplaced by inte~al co~ ustion en~ines Ele~triG motors 10 are the drivi~g units of respective first and second drive trains, w~ic~ are located on tlle le~SL side and the ri,~ht sioe, rcspecti~ely, of a ~notor vehicle such as a ~us. The electric moto~s 10 have S~al~LS ~r~ich are coImeeted ~h~ough universal joints or yokes 12 ~o ~eSpec~ive first and second drive sh~s 14. Dnve shafts 1 2 0 exterld horizontally, lon~tll~in~lly and I ~al wdldly ~om motors lO along a~es which are parallel to the vehicle cer~er li~ A ~rlive~sal join~s or yokes 16 are pro~ded at the re~ w~l~ cnds of shafts 1~ fo~ conne~tion to first a~d seGond i~put sbaflLs 18 of drive a~le assembly 20. I)rive a~le asse~bly 20 is prefe~ably a rear axle assembly, since the vehi~le d~i~Je wheels are prcferably located a~ ~he re~r of the vebide. I)rive axle assemSly 20 2s infhl~e~ first and second ge~r assemb~i~s 22 or 24, whiç~ are located eq~ ict~ntly on opposi~e sides ofthe l~ n~tu~in~l center line ~ ofthe vchicle. T~e gear assen~bly 22 may be a conventional di~c;~ ial 13ear ~ssembly 22, as sho~ in Figs 1 and 3, or may be a gear ~isç3nhly ~4, as sho~n in ~ig. 4~ co~t~inin~ only those ge~rs wbich ar~ required for purposes o~this inve~tion.
3 0 Fig. 3 illllstrates in detail a gea~ assembly 22 ~bich houses converJ~iohal dif~erential gears. ~s shown in Fig. 1, there are two su~h assembsies, one ~or e~ch ~rive ~rai~ Only F: 1.. -- ~ . ' . S L~ 4 22 Q ~ 5 7 ~

one will be described in detaîl si~ce all parts in eac~ asse~bly are either ideIItical to or are ~irror images of the co~espo~ding part.s in the ot~r ~.~sernhly EaG~ gea~ asse~hbly 22 comp~ises a gea~ ~ousing 2~, which, in tu~, includes a statio~ary outer housing ~embe~
o~ difl~erential carrler 26 alld a statioha~y cove~ ~ which ~nay be affl~ed to th¢ carrier s (e.g., by bolts not sho-vn). ~nput sha~ Ig is tot~tably journaled ih c8rrler 26 I?y means of roller bearing asse~blie~ 30 Input sha~ 18 ter~inates at one ehd ~the end which is ~0mote from drive shaflc 14) iIl a pihion gear 32. Ihput sha~ 18 thFoug~ pinio~ gear 32 d~ives a rotatable ~i~elllial ~asing 34, whiGh ha~ a ~ing ge~r 36 bolted or otherwise ~l~edly attached the~eto. Botb. pinion gear 3~ (a driving gear) and ring gear 36 (a d~iven gear) are 10 bevel gea~s. Casulg 34 is rotatably mountcd in car~ie~ 26 by means of ro~ler bea~ng assernblies ~7.
A difI~ Li~l gear assembly as sho~ivrl in Fig 3 filrther i~cludes a mouIIting pin 38 w}lich extends across the diffe~ential casir~ 34, fou~ ~li¢~ Lial bevel E~ea~s 40, alld a p~i~
of side gears ~. One of tlle two side ~ea~s ~the gear to the right as seen irl Pig 3) 15 d~iv~ngly engages a rotatable olltput sha~ 50, which extends fronl the interior of gea~
housing 25 to a side of the vehicle. This may be accon~plished by collventio2lal means, S-IGh as a splined Gonnection~ The ot~er side gear 4~ is not oper~tively connected to any output ~ember.
It will be appa~ent that a co~ventional .li~ Llltial gear assembly is not re~uired fior 2 0 ~is invention, since th~re is onl~ one o~tput shaflc in ea.~h drive train. :Eior convenie~ce (since di~e~e~tial gear assembl~es are usually readily available) a conventional di~ el.lial gear assembly may be used. It may also be r~ ired to lock out the di~l~llLial gear, w~ich may be accomplished by known ~neans.
~ second gear asse~bly 24, w~ich contams all of the gearin~ ~equired for ~he 2 5 purposes of this ihvention, iS showh in ~ig. 4. Ollly one gear assembly is ~ho~n since the other (showll in Fig. 2) consists of parts which ~e eithe~ identical to or are mirro~ images of co~espotldinE~ parts shown in ~g. 4. ;Referring now to Fig 4, gear asse~bly 24 includes a housing Gomp~sing ca~ier 26 and a cover ~8, which may be like t~e similarly nu~bered parts shovvn in ~ig. 3 Input s~c 18 t~ough pinion gear 32 thereo~
3 0 inte~neshes with and drives ~ ring gear 3~, which may be bolted to a hollow casillg ~ so that the ~o rotate together. ~ollow casing 48 is rotatably ~nolmted in the housi~ 4 by ~ 5 2~01579 ~eans of roller beari~g asse~nblies 46 Casing 48 driYirlgly eT~ s output $ha~ 50. This ~nay be aGco~plished by conve~tional means, such a.s a splined connection.
It ~ill be ~ioted that the gear housi~g 25 contains only two gears7 i.e. a pinio~ ~ea~
3~ (a drivin~ E~e~) and a ring gea~ 36 ~a d~iv~n gea~), both ~f which may be hypoid g~ars~
5 wllich a~e strong a~d ~uiet in ope~ation. AIte~rlatively, gEars 3~ and 36 may be bevel gears or the like.
Output sha;Pcs 50 of the two gear asserIIblies 22 or 24 ~e axially aligned axle sha~s which extend outwardly alorlg a com~on transve~se axis B ~o~ the respecti~e gearhousings 25 to respeGtive sides of tlle vehicle. l~ach output shaPL 50 rnay terminate at its 10 outer end i~ a cirGular dis~-like end oap 51 l~ach of the output shaP~s or axle sha~ts 44 r~ay be replaced by 8. pair of coaxial shafts ~rhich drivi~gly erlgage each othe~ so tha~ they rotate t~gether~ but ordinarily a single s}~a~t is used.
Surroundin~ eaGh re~ axle sha~ 50 is a stationa~y tubul~r axle hou~ing 52, shownbe~e as beLng fo~ed by two cotlcentr~c tubes 5~ and 56 such that the ~nside diameter of l S the first t~be 5~ is the sa~e as or slightly less than the outside diameter of the spi~dle or second tube Sfi. Botll tubes are concentfic with t~e axle s~aft SQ ~Ithou~sh shown as separate components, the tubes 54 ~nd ~6 may be made as one integral compone~t if ~esired. ~ach axle shafl: 50 and each tubular ho~sir~g 52 exterlds from a gear housing ~5 to a side of thc bus, and tenDinates at an oute~ end urhicl~ is in proximity with a wheel 2 0 asse~bly. The ou~er end of each a7~1e housing ~ is sli~htly inboard of the outer en~ o~the co~res~orlding a7~1e; shaft 50 (to pe~it end cap 51 to e~tend radially outwardly form the axle shaflL SO), However, each axle housin.~ 5~ (and, specificaIly, spindle S6 thereof) e~ends transversely out~oa~d of a major po~tion of a wheel assembly (to be described in ~cta~l subse~uently~ mounted the~eon, Tubular housirlg 52 is secured, for e~ar~ple by 25 bolts (not shown), welding or other suitable SeGU~ing ~netllod~ to th,c gea~ housing 22 o~
~4.
~ tendulg fro~n one gear housirlg 25 to the other is a transverse horizontal :,LiD~e.~ g mem~e~ 60 This stif~elling member liO unitizes the rear axle assembly ~0 and the two dnve t~ains therein irlto a unita~y str,ucture. ~t also m~int~in.q the two d.rive 3xle 3 0 shaf'cs 50 irl axial ali~nmerlt ~nd in substantially ~orizonta~ position (~nless the vehicle wei~ht load ori one side of the center li~e i~ appreciably gre~ter tha~ on the other). This 2 2 û ~ 5 7 ~

~ember must be strollg, si~ce it is subjecte~ to cornpressive skesses by vellicle weight or load thereon. Stif~ening rnember 60 ma.~ be either a solid bar or a hollo~ tube, bu~ t}le ~atter is ~1 ~re~l~d because the gre~ter st~ength-to-weight ratio.
Stiff~nin3~ me~ber 60 is placed at an elevation lowe~ tha~ that of the gear housings 5 2S and the rear axle sha~cs ~iO. A pair of vertical and do~vnwa~dly exte~ding housin~3 co~nectillg members 62, whiGh may be hollow~ connect the sti~enirll3 me~ber ~ivith gear housihgs 25. ~or ease of repair, the sti~ening membe~ 60 rrlay be remo~ably af~ed to the ~ear housings 60. 'rhis may be ac~om~lished either by forxr~ing the deperlding ~ousing member 62 integral ~ith ~espective gear hou~ings 25 and joining the sti~ening rlleml~er 60 10 to the depe~ding ho~sing ~¢mber 62 by bolts, or by fo~ing the ~LiLr~ g membe~ 60 a~d the two housing me~bers 62 as a unit, a.nd aff~Lxi~g the two ~ousiIIg me~bers 62 by bolts to ~espective geQr ~ous~s 2~. Sti~fening ~em~er 60 is placed at a lower elevation than that of the gea~ housings ~2 or 24 so t~at the ~llS can have a low floor F ~sho~ in a broken line in Fig. 2), lower tha~ the top level of the gea~ housirl~s 2~ a;nd eve~ lower than 15 the d~ive ~le s~aPcs 5~. Floor level F Frlay ~e the floor level th~ougllout t~e entj~e b~s, e~n-lir~ the length of the bus and the erltire width of the ~ous ex¢ept at the fi ont w~eel assemblies (not shown) and t~.e rear wheel Assenlblies ~shown in Figs 1 ~d 2) and the gea~
hollsings 25. Even i~ the v~cimty of the gea~ housirl~s 25, the low ~oo~ ~ is wide enough to provide a center aisle T~e low floor ~ac~litates loadiIlg of both orthopedic~lly 2 o haIIdicapped passellgers (inf ~ in~ t~ose who use ~;vheelc}lai~s) and passenge~s having no orthopedic impai~ent.
~ o~ olltal spring pads 64 a~e ~orlned on top of the respecti~e gear ~ous~n,gs 25, for ~eceiving springs 66 ~rhich fiorm part of a vehicle suspe~sio~ system. Springs 66 are sho~ diagr~1n~A~ir. llly in chain lines as air spri~gs, wllich a~e the ~r~led fo~m of 2 5 sp~ings. ~ part of the vehicle ~eig~t, that is, that po~tion which i8 bor~e by thç ~ear wheels aTld ti~es, is borne by ~he air springs 66 and the sprin~ pads 6~.
pair of wl~eel assemblies 70 are rotatably mounted on outer port.ions o~
~espective spindles S~ at l~s~;Live sides (the le~ side a~d t~e right side) of the vehicle.
E:ach wheel assembl~ 70 comprises a hub 72 which is rotatably ~ounted on an oute~
3 0 portio~ of a~le hnu~in~ 52 (and specifically spindle S6) by mea~s o~ a plurality o~ roller bearing asse~lies 73. ~Iub 7~ is attaGhed by bolts 74 to tb~e end cap 51 o~ axle shaft 50.

.. ~ r 7 -, ~1 The hub 7~ is also secured ~o spindle 56 by nuts 81 or other suitable ~echanism. ~
plu~ality of mou~ti~g studs 76 secure wheel rims (not shown) and a ~rake d~m 78 to hub 72. Normally, the vehicle wiU have double wheels (an inside w~eel ~2ld an o~ltside ~heel) o~ ~he a}~le, and S07 p~efierably, two wheeI rims are secured to the ~ub 72. (If the ~us has 5 tarldem rear axles, eaGb. rear ~le ~ill no~mally have double wheels on each side of t}~e bus.~ A ~eel a~sembly filrther includes a bra~e s~oe 80. The br~lce StrllGture is not shown i~ detail ~,ince it may be conve~tional a~d ~orms no part of the in~e~tion.
Modular de~ign and const~uction ~e used i}l the practice of this ~ventioll.
Compo~e~ts ca~ be ~e~ovably sec~red to~ether, for e~ample, by bolt~g, as p~eviously 10 e~crl~in~rl. Thus, SL~ rnember 60 can ~e removab~y secured p~eviously by bolts, to both gear housings ~ Each a~le ~ousing 52 can be secured, e.g., by bolts, to an adJac~nt gear housi~.g 25, The invention ~ay utili~e a convelltional spindle a~rangenlent, whi~ in tu~n mal~es it possible to use standard or existi~g prod~ction hubs, brakes, brake drums, a~de hollsings, a~le shafl:s~ and gear assernhli~ This also ~nakes it possible to ~epair or 1~ replace one compollent witho~t disturbing other con~ponents. Fo~ ç2~ample, ~ gear assembly 22 or 24 ~an be removed ~OIIl the vehicle w~thout havin~ to remove the wheels a~d other comporlents, such aS the a~le housinE~s 52. This also mak~,:s ~t possible to ~eplace compOIlents ~ith larger or s~all0r co~ponents havin~ the same fimctiotl. ~or e~mple, if o~e desires a b~s ~aving a wider o~ narrower ~'track" (which is the di~ta.nce between 2 0 whcels on the two opposite sides o~a bus) one replaces the origin~l axle ~afts 50 aIld axle ~ousings 52 with longer or s~Oner axle shafcs alld axle ho~sings as desired. Alterna.tively, tlle length of t~be 60 could be ch~nged to accomptish a sim~Iar purpose Simil~ly, one can replaGe the ge~r assemblies 22 or 24 wi~ gear assemblie~ ~ho~e ~ousings are of larger or smaller gear ratios, ~vhere applupliate, and can replace co~ventional lli~er~l,tial assemblies 2 5 22 (with tlle .li~e~ c~ locked out) with speciall~ des;gn~d gear assemblies ~4 hav~ng onl~
the necessaIy gears, or ~ice wrsa.
Tlle presellt in~entil~n also protects the drive axles 50 from defl¢ction caused by vellicle load or weight. In other ~ho~ds, the present inverltion provides a fi~lly floati~g drive ~xle assembl~ for a twin motor (or more b~oadly, a plural Inotor) ve~icle That 30 portion o~ehicle weight ~vhich is borne by the ~ear axle ~ssembIy 20 is tr~n~rnitted through air springs 66 to spring pads 64, ~hich are forIIled on the ~ear housings 2~. ~rom F~ ' l'L 8 ~ 2 ~ 9 t~e~e such stress is ~r~n,cmitted transversel~r out~a~dly throug~ the cpindles 52 to t~e whe0l assemblies 7~, which are ~otatably ~ounted on t~e spindles S~. Vehicle load or w0ight is the~ tr~ncmitt~d ~om the ~heel assemblies to ground~ gin.1~ tires (not s~own).
Loolcing at weight load t~n.~mi.qsion f~o~ another vit wpOill~ (SincE unde~ ~ewton7s laws, 5 for every action there is a~ equal an opposite reaction~ eight lo~d bome by the ground-erlg;~ wheels is a~ .,illed through ~heel ~ssemblies 70 to spin~les 56, a~le tubes 5~, alld ho~sing ~emberc ?5, thence to sprin~ pads 6Lt and vehiGle springs ~i6 By mourlti~g t~e wheel assemblies on stationary a~i;le housings 52 and not on t}le axle shafts SO
themselves, the a~e sh~fts SO are out o~ the pat~ of weight load t~ncm~ on a~d ~o are 10 not sllbject to stress~causin~g deflection. Ir~ short, t~e axle sh~fts 50 are noln-load bearin,g.
This greatly inGreases axle sha.ft life and minill1i7~s premature axle sha~ failure. This also m~es it possible to optinaize parts, s~ch ~s axle shafts SO, to perfo~ a single fiulGtion.
Thus, the design ofthe a7sle sha.f~s 50 can be ~,~LiL~ ed for deli~ering tor~ue f~or~ the g~ar assem~lies 22 or 24 to the wheel assemblies 70. Fsilure o~axle sha*s from ove~ torquing 15 is very unlil~ely to occw. ~n contrastr arl axle assembly design in w~ich axle sh~fts Garly torque to t~e wheel$ a~d support t~e weight of the ~e~iGle~ there is a danger ofoverloadillg the a~le shafts with co~pound loadi~g, whiGh typically will c~use exGessive ~tigue and ~ay even cause a wheel to fall off.
~ filrther advantage of t~e present inventioll is that i~ utilizes hypoid or bevel gears~
2 0 rather thall worm gears (as shown ill published information concerning an olde~ bus mode]) where tr~.qmi~.~ioIl of tor~ue fro~ a drive shaflc to all a~le shaft.
~ Vbile this inverltion has beell desc~ibed with ~eference to the best mode and ~r.3rell ~d embo~ t it vvill ~e understood tha.t this description i~q by wa~ of illust~ation and not by ~ay of li~tation. Va~ious modif;c l~ions can be made w~t~out departin~ ~o~
2 5 the scope a~d sp~rit of tl~is inventioll.

r \ '!'~'~ ........... ~.UY

Claims

What is Claimed is:

1. An automotive vehicle comprising:
(a) first and second motors disposed on opposite sides of a longitudinal center line of said vehicle;
(b) first and second drive shafts extending longitudinally from and driven by said first and second motors, respectively;
(c) a full floating drive axle assembly comprising:
(1) first and second transversely spaced gear assemblies, each gear assembly comprising a gear housing having therein a driving gear driven by one of said drive shafts, and an output gear in meshing engagement with said input gear;
(2) first and second axially aligned and transversely extending axle shafts drivingly connected to respective output gears in respective first and second gear housings;
(3) first and second stationary tubular axle housings joined to respective first and second gear housings and extending transversely outwardly therefrom;
(4) a stationary horizontal stiffening member secured to said gear housings and extending transversely from said first gear housing to said second gear housing, said stiffening member being at a lower elevation than said gear housing; and (d) first and second wheel assemblies rotatably mounted on respective first and second axle housings and drivingly connected to respective first and second axle shafts.

2. An automotive vehicle according to claim 1 wherein each said axle housing surrounds and is spaced from an axle shaft.

3. An automotive vehicle according to claim 2 wherein each axle housing terminates at an outer end in proximity with an outer end of an axle shaft surrounded thereby and outboard of a major portion of a wheel assembly mounted thereon.

4. An automotive vehicle according to claim 1 wherein said input gear and said output gear are hypoid gears.

5. An automotive vehicle according to claim 1 wherein each said gear housingcontains an input shaft said is coaxially aligned with one of said drive shafts, and a rotatably mounted casing axially aligned with said output gear, and wherein further said input gear is a pinion gear formed of an end of said input shaft and said output gear is a ring gear affixed to said casing.

6. An automotive vehicle according to claim 1 wherein said drive axle assembly is a rear axle assembly.

7. An automotive vehicle according to claim 1 wherein each said motor is an alternating electric current electric induction motor.

8. A drive wheel and axle assembly comprising:
(a) first and second transversely spaced gear assemblies, each gear assembly comprising a gear housing having therein an input gear adapted to be driven by an external longitudinally extending drive shaft, and an output gear in meshing engagement with said input gear and being adapted to drive an axle shaft;
(b) first and second axially aligned and transversely extending axle shafts drivingly connected to respective output gears in respective gear housings;
(c) first and second stationary tubular axle housings joined to respective first and second gear housings and extending transversely outwardly therefrom;
(d) a stationary horizontal stiffening member secured to said first and second gear housings and extending transversely therebetween, said stiffening member being at a lower elevation than said gear housings; and (e) first and second wheel assemblies rotatably mounted on respective first and second axle housings and drivingly connected to respective first and second axle shafts

9. A drive wheel and axle assembly according to claim 8 wherein each said axle housing surrounds and is spaced from an axle shaft.

10. A drive wheel and axle assembly according to claim 8 wherein each axle housing terminates at an outer end in proximity with an outer end of an axle shaft surrounded thereby and outboard of a major portion of a wheel assembly mounted thereon.

11. A drive wheel and axle assembly according to claim 8 wherein said input and said output are hypoid gears.

12. A drive wheel and axle assembly according to claim 8 wherein each said gear housing contains an input shaft which is adapted to be driven by a vehicle drive shaft, and removably mounted casing axially aligned with said output gear, and wherein further said input gear is a pinion gear formed on an end of said input shaft and said output gear is a ring affixed to said casing.