Thin-Walled Structures41(2003)1041–1052
A thin-walled,dual-curved,steel band wheel
with inherent spring suspension for u on
heavy vehicles
Justin Batelaan∗
25Charterhou Road,Toronto,Ontario M1S2T4,Canada成熟英语
Received26July2002;accepted3March2003
Abstract
A new vehicle suspension system,called band wheel or track wheel,is in an early stage of development.Band wheel prototype models have low rolling resistance and a good load capacity.Its unique component,the spring band,is a thin-walled,dual-curved,amless steel oval band with rubber tread.Mechanical properties of band wheel and spring band,designed for u on heavy road vehicles,a
re described in some detail.The lower spring band gment provides spring suspension with a very low unsprung weight.Suspension characteristics are derived from measurements on prototype models.A band wheel could replace a t of dual wheels with tires and its suspension on a heavy vehicle as a pavement-friendly alternative. Other potential applications include armored vehicle and airplane landing wheel.Afinite element analysis of spring band is propod and outlined as a further step in band wheel development.The author,who is about to retire,offers prototype models,special tools,docu-mentation and a US patent to a company or institution with an interest and commitment to continue this development.
Keywords:Band wheel;Track wheel;Spring band;Heavy vehicle;Suspension;Thin-walled band;Pave-ment friendly;Armoured vehicle;Landing wheel
∗Tel.:+1-416-291-3625.
E-mail address:j.batelaan@utoronto.ca(J.Batelaan).
1042J.Batelaan/Thin-Walled Structures41(2003)1041–1052
卸妆乳怎么用
Nomenclature
三星广告背景音乐c arc of spring ban
d cross-ction
E modulus of elasticity
L length of unmounted spring band,between centers of elbows
P load force on band wheel
r transver radius of unmounted steel spring band,upper and lower gments欧美经典电影推荐
R longitudinal radius of unmounted steel spring band,upper and lower gments
S circumferential length of band
t thickness of steel spring band
W width of spring band
s fatigue stress limit of steel band
r radius of curvature due to bending
1.Introduction
A steel band vehicle suspension system,called‘band wheel’or‘track wheel,’is in effect an oval-shaped resilient wheel with two axles and a large rolling radius. Its unique component,called‘spring band’or‘spring track’is a amless,dual-curved,thin steel band.This thin-walled loop structure was analyzed in a rudimentary manner only,and not by a comprehensivefinite element analysis.Prototype models were build and reveal a number of promising features which are of benefit in many potential applications.The features and test results are prented in my earlier paper describing the benefits of band wheel for u on an all-terrain vehicle[1]. Prototype models of band wheel have demonstrated good load capacities and a low rolling resistance,similar to automotive wheels with radial tires.Band wheel is superior to loopwheel,another resilient band suspension which was developed and later abandoned by Lockheed’s Huntsville Rearch Engineering Center from1969 to1983[2,3].
Pavement damage by heavy vehicles is a major contributor to the maintenance costs of roads around the world.Also,trucks are growing larger,more powerful and plentiful.The technical issues of heavy vehicle tire forces and pavement damage were studied extensively and reported on[4,5].The most significant factors in gener-ating high fatigue stress levels in the pavement are axle load,tire diameter and tire pressure.In particular,larger diameter tires and lower tire pressure reduce stress in the pavement and conquently pavement damage.A band wheel designed for u on heavy road vehicles meet the requirements,and is described in some detail as another example of a potential band wheel application.
pbskids1043 J.Batelaan/Thin-Walled Structures41(2003)1041–1052
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2.A thin-walled steel truck wheel
An outline drawing of band wheel for u on heavy vehicles is shown in Fig.1. Thefive major components of this band wheel are:
1.Spring band.A amless,dual-curved,thin steel band with a rubber tread.
2.Band support rim.Four band-support rims,with aflange,fit into the natural radial
curvatures of the two spring band elbows,one on each side of the elbow.nrt
3.Band wheel frame and forward rims arm.Truck load and braking forces are trans-
ferred by this part to the forward rims and to the rear rims arm.The forward support rims turn on an axle in this arm.
4.Rear rims arm.The rear support rims turn on an axle mounted in this arm.This
arm swivels on a pivot of the band wheel frame.
5.Retention spring.The wire spring,wrapped around the arm pivot,press the rear
support rims into the band elbow.It retains the band on the rims when there is no load on band wheel.(Other retention spring designs are possible.)
Fig.1.Outline drawing of band wheel under nominal load.
日神
辅音音标1044J.Batelaan/Thin-Walled Structures41(2003)1041–1052
Not shown in the drawing is a brake mechanism which can be designed in between the forward support rims and the forward rims arm.A drive axle to the forward support rims is not shown and is required if the band wheel is ud for propulsion of the vehicle.A hinged band support frame,as shown in Fig.1,provides sufficient friction between forward rims and spring band to transfer road traction forces in braking and propulsion[3,p.217].
Band guards may be required on either side of band wheel to prevent pavement debris getting trapped inside the spring band.All the components,except for item 1,can be designed and produced using well developed engineering practices.Spring band,however,was never produced on a routine basis and will require a major development effort.
3.Spring band features
katy perry 格莱美Spring band is the rotating part of band wheel which transfers load and traction forces from the band support rims to the pavement,and is equivalent to a tire on a regular wheel.This resilient band was c
alled‘spring track’in earlier papers;how-ever,spring band may a better descriptive name.When spring band is removed from its support rims it retains its natural oval geometry as shown by the drawing in Fig.2. The fundamental dimension of spring band is r,the radius of the band cross-ction.The longitudinal radii of the elbows in the band take on the same dimension r.The large longitudinal radius R is formed into the steel band.When a band gment moves into the elbow,the band cross-ctional radius changes from r to R.The band is always under stress in the elbows,both,in the longitudinal direction and in the transver direction.When the band is cut anywhere,it springs open to a stress-free, dual-curved steel tape gment of length S and with radii r and R.A photograph of prototype models of the steel spring band is shown in Fig.3.
A most significant feature of this thin-walled structure is the dual bending of the band under load.A reactive force from the pavement bends the band longitudinally, as well as transverly at point of load.Longitudinal bending of the curved band caus an upward force at its edges and a downward force in the center.The small transver bending forces are greater for bands with a relatively small longitudinal
Fig.2.Steel spring band and its major dimensions.
1045 J.Batelaan/Thin-Walled Structures41(2003)1041–1052
Fig.3.Prototype models of steel spring band,about40cm overall length.
radius R.The steel band cross-ction bends from a radial curvature,to a higher and slightly narrowe
r,parabolic curvature.This change in geometry caus the band to flatten and stiffen in the longitudinal direction.Dual bending of the band under load increas load capacity and also provides a longer foot print on the pavement.Differ-ences in band cross-ctions are shown by the three views in Fig.4.Note,the steel band cross ction is higher and narrower at the bottom than at the top.
Bands with relative large radius R,or a minimal initial longitudinal curvature, have limited transver bending under load;in particular when the band is supported by tread in the centre of the band.For that reason the tread is located clo to the centroidal axis of the band cross-ction and not only in the center.This enhances
Fig.4.Cross-ctions of spring band with rubber tread,under nominal load,in three places.
