Note: Descriptions are shown in the official language in which they were submitted.
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REAR ~FFSET ~XLE ~USPENSION ~YSTEM ~O~ YEHICLE
BACKGROUND OF THE _INVENTION
The present invention relateR generally to rear
axle leaf spring ~uspension ~yste~s for motor vehicles
and more ~pecifically to a ~spension system with an
offset rear axle.
Suspension ~ystems for rear, non-driven wheels of
motor vehicles which ~mploy offset axles are known in
the art. U.S. Patent No. 4,410,201 issued October 18,
1983 i~ exemplary ~f these prio~ art 6ystems. The rear
axle leaf spring &uspension ~yste~ of the present
invention i~ dir~cted at improving the known prior art
systems in certain respects æuch as economy of
manufacture and compactness of design, while providing a
smooth relatively harsh-free ride.
It is accordingly an object of the present
inYention to prouide an ~conomical, easily assembled
rear wheel leaf spring suspension system for a motor
vehicle with leaf ~prings supporting lateral, vertical
and~ longitudinal load~ o~ the vehicle body together with
a forwardly and downwardly offset ~traight tubular a~le
me~ber ext~nding transversely to clear depending vehicle
underbody components.
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~ It is another object to provide a rear axle leaf
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~pring ~UBpen~iOn ~y~t~ configured to achieve ~ r~uced
vehicle design ~eight.
It is yet another object to provide in the off0et
rear axle leaf ~pring su6pension systen ~ wheel ~upport
apparatus having improved st.rength and reliability
characteristics.
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According to ~ feature of the invention a
forwardly offset axle system is provided in which a
tubular transverse axle menber of constant circular
cross-section is forwardly offset from the rear wheel
~pindles to pass between the vehicle gas tank and spare
tire carrier supported on the under~ide of the body
floor pan. A pair of mirror image axle castings
support each en~ of the offset axle providing leaf
spring and wheel spindle seating means in co~bination
with a telescopic shock absor~er strut mounting and a
jounce bumper stop plateO
BRIEF DESCRIPTIO~ OF THE DRAWINGS
_ _..,.. ...~_
These and other ob~ect6 and features will become
apparent to those sXilled in the vehicle wheel
suspensil:>n art upon readin~ the following description
with reference to the accompanying drawin~s in which:
Fig. 1 is a fragmentary perspective view of a rear
a~le 6 pension ~ystem with part~ broken away embodying
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the invention;
~ ig. 2 i~ a perspective, exploded view of the rear
wheel ~u~pension sy~tem of ~ig. 1;
Fig. 3 i~ a fragmentary frvnt elevational Yiew,
partly in section, of the rear a~le suspension ~y~tem of
the present invention;
Fig. 4 is a frag~entary top elevational view, with
parts broken away, of the rear axle suspension ~ystem o
its present invention; and
.
Fig. 5 i6 a fragmentary side elevational view of f
the rear s~spension with lower rebound and upper jounce
deflection positions ~hown in dashed lines.
DETAILED DESCR~PTION OF T~E PREFERRED EMBODIMENT
Referring now to the drawings, and in particular
to Fi~s. 1 and 2, there is shown a leaf spring
suspension system 10 for the rear wheels 12 of a motor
vehicle having a body partially indicated at 14. The
suspension ~ystem i~ adapted to:be carried by the
vehicle frame including æide frames or raîl~ 16
rei~forcing body flo3r pan 18.
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As ~een in ~'ig. 2 the rear axle suspen~ion system
10 con~i~ts essentially of a pair of multi-leaf springs
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20, a non-driving rear axle ~ssembly 22 rot~tably
~upporting the rear road wheel~ 12, a pair ~f wheel
support spindle~ 24 for mounting the wheel~ at the end6
of the off~et axle asse~bly and a pair of telescopic
~hock absorber ~trut6 26 of known design int~rconnected
between the axle a~sembly and the motor vehicle body.
In the following description, it should be under6tood
that becau6e of the symmetry of the su~pen~ion ~y~te~
ab~ut the longitudinal centerline of the vehicle, only
~ne of the pair of identical a~le and suspension
components will be described.
I~e multi-leaf spring 20 has il resilient bushing
28 captured within an eye 30 at its front end. The
bushing 28 is connected to a hanger 32 in a conventional
manner by means of bolt 34. The hanger ~2 is ~uitably
fastened to body floor pan 18 by bolts 36. At its aft
end the multi-leaf spring ~0 is formed with an eye 38
receiving a first ~olt 40 of a shackel for~ed by a pair
of parallel plates 42 and 44. The shackel is conneced
to a bracket 45 by a second bolt 46 extending through
bushing 48 of the bracket. The bracket 45 i8 secured to
the vehicle body floor pan by means of bolts 49.
As best seen iQ Figs. 3, 4 and 5 the axle assembly
22 includes a transverse straight tubular ~ember 50 of
constant or uniform circular cross~ection having a pair
of left and right integral ca~tings 52 received on
either end thereof. As the castings are mirror images
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¦ of each other only one c~sting w~ll be described in
¦ detail along with its a~sociated ~ulti-leaf spring 20
¦ ~nd shock absorber 26.
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Ihe casting 52 include~; nn inboard collDr portion
54 and an outboard L-~haped D~em~er 55 having a
vertically extending spindle mounting plate 56
integrally formed with an intermediate connecting body
or bridge portion 58. The ca~ting collars 5~ ha~e
transverse bores 59 sized to receive the end~ of the
tubular axle mem~er 50 in a pres~ fit ~anner. The axle
member 50 is al~o welded to the collar to com~lete the
press fit connection. The bridge porti~n includes a
first substantially horizontally di~posed plate 60 of
the L-shaped member, integral with the vertical plate 56
and a triangular upstanding we~ 6?.
The horizontal plate 60 has a planar ~ounting
~urface 64 sized to seat an intermediate portion 65 of
the leaf ~pring 20. Ihe lea~ spring is connected to the
plate ~urface 64 by a pair of U-bolt clamping fixtures
generally indicated at 66 retained by nuts 67. To
prevent any longitudinal movement of the leaf spxings 20
relative to the casting 52 a threaded stud 68 extends
vertically through aligned holes in the center of plate
~urface 64 and multiple leafs of ~pring 20. It will be
noted that the leaf ~pri~g ~ay have either 4 or 5 leaf
assemblies, in the preferred form, allowing the
~uspension to be load tailored to the vehicle weight.
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The bridge portion 5~ further c~pri~e~ an
integral truss portion h~viny a flrst triangular shaped
flanged truss portion 70 exte~ndin~ transver~ely and
coexten~ive with the hori~ontal plate 60. The bridge
portion incudes a second par~llelogra~ shaped tru6s
portion 72 angled inwardly and forwardly fro~ portion 70
for juncture with he aft area of integral collar
portion 54. In Fig. 4 the right hand casting 52 i6
~hown with portions broken away indicating the inwardly
and forwardly angled orientation of the parallelogram
shaped truss portion 72. The truss portion 72 is joined 1.
to the transversely extending triangular shaped truss 70
at the inboard edge of the plate 60.
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It will be noted in Figs. 3 and 4 that the casting
plate 60 is joined to a horizontally dispo~ed jounce
plate 74 by an inwardly and downwardly inclined upper
flan~e plate 76 coextensive with the angled truss
portion 72. The jounce plate 74 upper surface provides ,,
a bumper stop limiting the upward travel of the axle
suspension system upon contact with a frame bumper
member 78. As seen in Figs. 2 and 3 the bumper member
78, formed of rubber or pla~ti~ material, is fixed to
horizontal bight portion 80 of its associated &ide frame
members 160 Each bumper me~ber 78 is secured by means
of a locking tab 8~ r~Pceived in a corresponding bight
~lot (not ~hown) and ~ tonque portion 84 receiving a
b~lt for threaded ~ttachmant to the bight portion 80.
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Fig. 2 ahows each ~ r portion 54 for~ed with n
depending bo~ 88 having a tran~verse bore for receiving
a t~readed bolt 90. ~he lower end of shock ~bsorber
~trut 26 ha~ an eyelet 92 apertured to receive the bolt
90 pivotally securing the strut lower end to itB
associated casting intermediate its leaf ~pring 20 and
the outboard end of collar 54. The upper end o~ the
RtrU~ 26 has an eyelet 94 receiving a bolt 96 pivotally
~ecuring the ~trut to flange 98 on the underside of the
body floor pan 18.
With reference to Fig. 5 it will be ~een that the
rear axle suspension system of the pre6ent invention
allows the axle assembly to travel from a lower rebound
position to an upper jounce position. During this
travel the forwardly offset tubular a~le ~ember 50,
shown in its neutral full line position, moves fro~ a
lower rebound deflected position 50' to an upper jounce
deflected position 50". It will be noted that the
syctem provides an uppermost jounce defleeted limi~
position wherein each casting jounce plate 74 contacts
it associa~ed frame mounted bumper 78.
In Pig. 5 it will be ~een that the forwardly
offset tubular a~le member 50 in its upper jounce
deflected position is lon~itudinally spaced interme~iate
fuel tank 100 and spare tire 102, both shown in phantom
lines. This su~pension structure allows the rear wheel
~pin 24 to be po~itioned rearwardly and upwardly of
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the ~xle ~ember 50 providing a longer whee1 base
di~en~ion for the vehicle. ln the preferred ~or~, the
ca6ting design achieve~ ab~ut a four inch rear offset
and a four inch vertically uE~ward offset for the rear
wheel spindle~ 24 from the center of the tubular axle
~ember 50.
Further, applicant~ unique de~ign allows each leaf
~pring ~0 to be positioned vertically within the
transverse confines of its corresponding spindle
mounting flange 104. This compact arrangement permit6
the leaf ~pring intermediate portion 65 to be located
vertically below the axi~ of the ~pindles 24 and above
the tubular axle 50. As a re~ult the overall body
structure is lowered relative to the axis of the
spindle~ reducing the vehicle' 5 overall height. The
tubular axle member 50 and end castings 52 reduces cost
of the axle assembly over other conigurations such as
I-section beams, for example.
The employment of the straight tubular axle hollow
pipe membex 50, allows its ends to be readily press-
fitted into casting collar bores 59. ThlS avoids other
costly fabrication ~ethods ~uch as bending a tubular
member as shown, for e~ample, in the above mentioned
Iijima et al patent 4,410,201. It will be appreciated
that the b~nt tube of the Iijima patent result~ in high
~hear ~res~ condition6 at the bend areas. ~urther, the
Iijima a~le presents alignment proble~s during
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~anufac~ure and require6 th~t the ~xl~ be reinforced.
While only one embodiment of the inventive rear
wheel nuspen~ion apparatu~ has been deRcribed, otherff
are pos~ible without departing from the scope of the
appended claims.
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