WO1991004875A1

WO1991004875A1 - Rear wheel suspension

Info

Publication number: WO1991004875A1
Application number: PCT/US1990/005096
Authority: WO
Inventors: Adrian Tucker-Peake
Original assignee: Gkn Automotive, Inc.
Priority date: 1989-10-03
Filing date: 1990-09-10
Publication date: 1991-04-18
Also published as: CA2022883A1; ES2025996A6

Abstract

A wheel suspension for a vehicle that includes a pair of spaced apart transversely oriented links (30, 38) that are pivotally connected to a vehicle chassis at one end and pivotally attached to a wheel support knuckle (16) at the other end, a leaf spring (24) positioned between the transversely oriented links (30, 38) and interacting with the wheel support knuckle (16), a tie rod (46, 74) attached to one of the transversely oriented links (30) and positioned in a diagonal attitude with respect to the transversely oriented links (30, 38) and the leaf spring (24), the tie rod (46, 74) passing through an aperture in one of the transversely oriented links (38) in one embodiment (Fig. 1) and passing in close proximity to one of the transversely oriented links (38) in another embodiment (Fig. 2). The tie rods on both sides of the vehicle can be united to form a continuous structure (64) that functions as an anti-roll bar.

Description

REAR WHEEL SUSPENSION

BACKGROUND OF THE INVENTIOK 1. FIELD OF THE INVENTION

The present invention relates to a suspension system for a vehicle such as a passenger automobile. More particularly, the invention is directed to a suspension system that is most suitable for application to the rear wheels of a passenger automobile: however, it will be appreciated that the invention would have application to additional vehicles.

2. DESCRIPTION OF THE PRIOR ART

Automotive vehicle suspension systems that utilize one or more transversely oriented leaf springs are well known in the prior art. Such leaf spring suspension systems provide for inde¬ pendent movement of each wheel connected thereto. With the intro- duction of front wheel drive automobiles, it is advantageous to provide for independent movement of each one of the rear wheels. In automobile suspension systems most widely used, the suspension systems employ coil springs or else multiple leaf springs that are oriented longitudinally with respect to the vehicle front to rear axis. Such an arrangement utilizing coil springs or longitudi¬ nally aligned leaf springs has a major disadvantage in that the structure of the vehicle adjacent to the wheel has to be designed to provide space to accommodate the springs and to withstand the loads that arise at the points where the springs are connected to the vehicle structure. Then, too, greater emphasis is placed on modular automotive assembly where entire subassemblies are united on the assembly line. From a production standpoint, it is desirable to be able to unite the entire rear wheel suspension system together as a subassembly then attach it to the automobile chassis with a minimum of fasteners in the shortest time possible. Also, since space is at a premium, it is mandatory that such subassemblies be as compact as practicable. Also, the compactness of the subassembly structure makes it easier to isolate noise that has its origin with the suspension system. Finally, a full con- nection to a vehicle frame increases the opportunity for double isolation of noise. The present invention employs a unitary leaf spring arrangement coupled with a self-contained linkage layout that avoids the disadvantages associated with the prior art suspension systems. The prior art reveals a wide variety of vehicular suspension systems that have been utilized on one type of vehicle or other. Several of the prior art devices provide for a fairly rigid attachment between the wheel and its spring biasing system. Adequate attachment of the wheel support system to the vehicle is mandatory: however, when the tie-down structure is too massive, the ride characteristics of the vehicle suffer.

The present invention is an improvement over the vehicu¬ lar spring suspension system shown and described in United States Patent 4.458.918 entitled "Rear Wheel Suspension with a Transverse Leaf Spring" and issued July 10. i984. to Manfred Rumpel. The above-referenced patent shows a suspension system for a rear wheel of a motor vehicle. Each wheel has a pair of transversely oriented laterally extending control arms that are pivotably con¬ nected at their outboard ends to the wheel support member. The arms are connected at their inboard ends to the vehicle chassis. The control arms are spaced apart and have a spring attachment bracket that spans the distance between the control arms and is attached thereto. The bracket accommodates the end of a transversely oriented leaf spring. The spring seat is pivotable with respect to the control arms to permit the control arms to undergo vertical movement while maintaining the spring seat bracket in a near horizontal attitude. In addition, wheel recession is partially controlled by a trailing arm that is attached at one end to the wheel support member and at the other end to the vehicle chassis at a location remote from the wheel support member. The unsprung mass is controlled in its movement by the usual telescopic shock absorbing strut.

The present invention is an improvement over the suspen¬ sion system described in the 4.458.918 patent in that there is no external trailing arm. The tie-in of an external trailing arm to the vehicle chassis remote from the control arms requires addi¬ tional space which is at a premium in compact passenger vehicles. Also, the necessi y for a connection between the control arms is eliminated by having the leaf spring end rest directly on the wheel support member.

An additional vehicular wheel support is presented in United States Number 4.614.359 entitled "Vehicle Wheel with Height Adjustment" and issued September 30. i986, to Donald G. Lundin et al. This patent presents the classical wheel suspension system in that a pair of spaced apart transversely oriented control arms help to provide stability to the wheel, yet permit it to move in a vertical direction. A leaf spring extends transversely across the vehicle chassis and is attached thereto. The ends of the leaf spring terminate adjacent to the wheel knuckle and actually bear on the shaft of an adjustable bolt that is attached to the wheel knuckle. The vertical motion of the wheel is attenuated by a shock strut that is interposed between the vehicle chassis and the wheel knuckle. Loads encountered in the longitudinal direction are reacted by means of a trailing link or radius rod that is attached to a chassis cross-member at one end and attached at the

other end to the wheel knuckle. The radius rod is fairly well aligned in the longitudinal direction of the vehicle.

The present invention also utilizes a pair of control arms with a leaf spring mounted therebetween. The present inven- tion does not. however, rely on an external trailing link, but rather utilizes an internally positioned tie rod to react wheel loads that occur in the longitudinal direction. Also, the present inventive concept permits the undercarriage to be assembled as a unit in a very narrow longitudinal space. In United States Patent 4.725.074, entitled "Vehicle

Suspension" and issued February 16. 1988. to Anthony Stevens, a suspension system for a pair of vehicle wheels is set forth. Accordingly, the patent 4,725.074. shows two arms positioned at each side of the rear of the vehicle. Each one of the arms is pivoted at its front end by an attachment to the vehicle chassis. A knuckle for the support of a wheei is attached to the other end of each arm. A conventional telescopic shock strut is positioned so that an upper end is attached to the vehicle chassis and the lower end is attached to the arm between the front chassis pivot point and the wheel knuckle. Also attached to the arm midway bet¬ ween its ends is the cantilevered end of a leaf spring that spans the transverse distance between the wheels.

While the above set forth vehicle suspension system minimizes space required for installation, the leaf spring is required to react load conditions other than the sprung mass. The leaf spring is required to withstand inwardly transverse loads produced for example by the curbing of a wheel. Also, bending moments are induced in the leaf spring since there are no trans¬ verse arms to act as a couple. thus, reacting bending loads. The present invention provides not only transverse stability in the horizonal plane but also prevents loads from entering the leaf spring in the horizontal plane. Since the leaf spring is essen¬ tially free of wheel induced torque loading, the spring is designed with appropriate rigidity to react the sprung mass in a manner that enhances the riding characteristics of the vehicle under partial as well as under full loads. The internally con¬ tained tie rod permits the rear wheel to handle recession without undue loading occurring on the leaf spring. The present invention permits a subassembly to be created that fits into the dimensional constraints of a compact vehicle.

The present invention is also an improvement over the suspension system disclosed in United States Patents 4.245.853 and 4.269.432 entitled "Independent Wheel Suspension for Motor Vehicles", issued respectively January 20. 1981. and May 26, 1981, to Hitoshi Inoue et al. The above-listed patents show and describe a suspension system for a rear wheel of a motor vehicle. A wheel hub is attached to a vehicle chassis by front and rear support arms. Additionally, a tension rod couples the wheel hub to the vehicle chassis. The tension rod is depicted as being attached to the wheel hub. however, the subject patents disclose the tension rod can be connected at one end to the front support arm. In order to prevent excessive toe-out. the attachment points of the front and rear support arms to the chassis span a distance that is greater than the distance between the attachment points of the support arms at the wheel carrier. In contrast, the present invention minimizes the distance between the front and rear sup¬ port arm chassis attachment points.

In United States Patent 4.511.160. entitled "Vehicle Rear Wheel Suspension" issued April 16, 1985, to Hitoshi Inoue. a rear vehicle wheel is supported by a pair of pivotable lateral links that connect a wheel hub to the vehicle body. A longitud nal link is provided to stabilize the wheei in the fore and aft direction. The longitudinal link is resilientiy mounted so tha it can follow the wheel movement. The geometrical arrangement the lateral and longitudinal links results in a toe-in motion o the wheel when it is bumped in an upward direction. In the pre sent invention, a rearward displacement of the wheel is not rel upon to control the toe-in of the wheel.

In United States Patent 4,714.132. entitled "Suspensi of Vehicle" issued December 22. i987. to Tetsuo Hattori et al, vehicle rear wheel suspension is shown and described. A subfra is attached to an automobile body by a series of elastomeric couplers. Front and rear links are utilized to connect a wheei hub to the subframe. A strut bar. that extends in a longitudin direction of the vehicle, is attached at one end to the automob body and at the other end to the wheel hub or to one of the lin adjacent to the wheel hub. The front and rear links are attac to the wheel hub so that a lateral force, when applied to the wheel, will result in minimal movement in the toe-out directio By mounting the strut bar to the automobile body, rather than the subframe. extra freedom of motion is attained because of t elastomeric couplers. The present invention does not rely upo resiliency between a subframe and an automobile body for wheel control. SUMMARY OF THE PRESENT INVENTION

The present invention provides a suspension system f pair of vehicle wheels having, for each wheel, a pair of later control arms that extend from proximate the longitudinal cen- terline of the vehicle to the wheel support knuckle, each of t control arms being pivoted at their ends for rotation. A leaf spring is transversely oriented between the control arms and attached at its central region to the vehicle chassis, with th cantilevered free ends of the leaf spring terminating in flexibl contact with the support knuckle, and a tie rod is aligned diago¬ nally with respect to the control arms with each end thereof resi liently mounted near the ter minal ends of the control arms. The invention also contemplates an arm attached to the wheel support knuckle and oriented diagonally forward of the control arms.

Preferably, the leaf spring of the present invention is fabricated from a composite, fiber reinforced plastic material. leaf spring so manufactured has the advantage of light weight for which composite material leaf springs are well known. The leaf spring can be designed to meet suspension requirements through material selection as well as the positioning of the reinforcing medium. While the various parameters, such as thickness and width, can be varied, it is desirable to fabricate a narrow width slipper spring.

A primary object of the present invention is to provide a vehicle suspension system that produces a soft ride for the vehicle passengers.

Another object of the present invention is to minimize the overall longitudinal extent of the suspension subassembly so that it can occupy a smaller space beneath the vehicle.

A further object of the invention is to provide excellent wheel steer control along with compliance control.

Another object of the present invention is to provide a progressively rising rate of resistance to a force that induces a rearward movement to the wheel assembly.

Still another object of the present invention is to pro vide a suspension system for a vehicle that permits tuning of the roll steer as well as the anti-lift angle. A further object of the present invention is to provide adequate toe-in of the rear wheels when lateral wheel loads are encountered.

A further object of the present invention is to provide vehicular trim adjustments without disassembly of the suspension system.

Another object of the present invention is to manufac¬ ture a lighter weight spring suspension superstructure that can be adapted to use either coil springs or a transverse leaf spring. An additional object of the present invention is to pro¬ vide a wheel suspension system that is compact and easy to assemble to a vehicle.

Further objects and advantages of the present invention will become apparent from the following description and the appended claims, reference being made to the accompanying drawings forming a part of this specification, wherein like reference numerals are used throughout the various views to designate like parts.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 is a partly sectioned perspective view of a wheel suspension system as viewed from the rear;

Figure 2 is a partly sectioned perspective view, similar to Figure 1, that shows an embodiment of the invention;

Figure 3 is a sectioned view taken along the line 3-3 of Figure 2:

Figure 4 is a plan view of an anti-roll bar that is con¬ nected to both sides of the vehicle:

Figure 5 is a partly sectioned perspective view that shows another embodiment of the invention: and Figure 6 is a perspective view of another embodiment that shows a self-contained compact wheel suspension structure.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

It is to be understood that the present invention is not limited in its application to the details of construction and arrangement of parts illustrated in the accompanying drawings, since the invention is capable of other embodiments and of being practiced or carried out in various ways within the scope of the claims. Also, it is to be understood that the phraseology and terminology utilized herein is for the purpose of description and not of limitation.

Referring now to the drawings and more particularly to Figure 1, there is illustrated a perspective view of a left rear vehicle wheel assembly as viewed from the rear of the vehicle. The overall wheel assembly is identified by the numeral 10. A longitudinal axis 12 runs from front to rear of the vehicle on which the overall wheel assembly 10 is mounted. As is common to most vehicles, a transverse axis 14 runs perpendicular to the longitudinal axis 12. While the axis 12 has been shown as common to the front and rear transverse links, the inboard ends of the transverse links can rotate about axes that are offset and parallel to one another. As shown, the transverse axis 14 coin¬ cides with the axis of rotation of the vehicle wheels. A wheel support knuckle 16 has cantilevered outwardly therefrom a wheel spindle 18 that is adapted to receive a wheel such as is iden¬ tified by the numeral 20. One end of a location device such as a telescopic shock strut 22 is attached to the support knuckle 16 and the other end of the shock strut 22 is attached to the vehicle chassis (not shown) . The positioning of the shock strut 22 is depicted in a vertical position between the wheel support knuckle 16 and the unsprung mass of the vehicle: however, it is con¬ templated that the shock strut 22 could be mounted in other than a vertical direction as well. The shock strut 22 is not utilized as a vehicle weight carrying device but rather to attenuate the jounce motion caused by the wheel 20 as it moves over a roadway surface. The shock strut is but one of the components of a suspension that adds to the overall compliance of a wheel suspen¬ sion system. A resiliently biased control arm could be substi¬ tuted for the shock strut 22 if desired. The main mass of the vehicle, sometimes referred to as the sprung mass, is supported by a spring biasing arrangement consisting of one or more springs positioned generally at each wheel of the vehicle. Figure 1 shows a leaf spring 24 that is oriented parallel to the transverse axis 14 of the overall wheel assembly 10. For the purposes of the pre- sent invention, the leaf spring 24 can be made of steel or the leaf spring 24 can be fabricated from a posite, fiber reinforced plastic material such as unidirectional glass fibers encased in epoxy or polyester resin. The leaf spring 24 is preferably fabri¬ cated in such a length so as to span nearly the transverse width of the vehicle. A slight camber is usually fabricated in the leaf spring 24 during initial layup and molding thereof. The camber helps to offset the effects of the sprung mass of the vehicle. For purposes of simplicity, the leaf spring 24 shown in Figure 1 has a constant cross-sectional area over its length. However, it is within the scope of the present invention to utilize a leaf spring 24 that has a varying width and thickness. The leaf spring 24 is anchored (not shown) to the chassis of the vehicle near the longitudinal centerline thereof. Normally a transverse leaf spring such as shown in Figure 1 spans the wheel to wheel distance, however, in some instances it may be desirable to uti- - il -

lize an individual leaf spring component for each rear wheel. If a two-part leaf spring is used, the ends of the leaf spring woul also be anchored at or near the longitudinal centerline of the vehicle. The leaf spring 24 has its end 26 cantilevered in a direction toward the vehicle wheel 20. The actual spring end 26 rests on the surface of a bridge 28. The bridge 28 is formed as reentrant portion of the support knuckle 16.

In the past, it has been common to connect the support knuckle to the vehicle chassis by means of a lower control arm that has the configuration of a wishbone. The so-called wishbone configuration constitutes a steel stamping which is quite rigid and has heretofore been relied upon for locating the wheel and permitting compliance. The present invention has moved away from the rigid lower control arm in that two transverse links are uti- lized. A rear transverse link 30 is pivotally attached to a lowe edge of the support knuckle i6 by a fastener, such as fastener 32. The fastener 32 is generally aligned so that its axis is parallel to the longitudinal axis 12. The rear transverse link 3 is aligned in an approximately horizontal attitude and extends inwardly from the support knuckle 16 towards the central section of the vehicle. An end 34 of the rear transverse link 30 adjacen the vehicle centerline contains a bushing 36 that is anchored within an appropriate aperture in the link end 34. The bushing 36 is made of an elastomeric material, such as rubber or polyurethane. A front transverse link 38 is attached to the lowe front edge of the support knuckle 16. The front transverse link 38 is also pivotally connected to the support knuckle 16 by a fastener 40. The fastener 40 has an axis that is generally in line with the axis of the fastener 32 that is utilized to anchor the rear transverse link 30 to the support knuckle 16. The front transverse link 38 is also disposed in an approximately horizontal direction toward the longitudinal centerline of the vehicle. An end 42 of the front transverse link 38 has an elastomeric bushing 44 that may be axially aligned with the bushing 36 of the rear transverse link 30.

As has been pointed out in the discussion of the prior art. wheel recession is generally controlled by coupling the overall wheel assembly 10 with an externally positioned trailing link. The trailing link or tie rod, as it will be hereinafter referred to, is generally anchored to the vehicle chassis at a location forward of the overall wheel assembly 10. In the pre sent inventive concept, a stabilizer member such as a tie rod 46 is attached to the rear transverse link 30 in close proximity to the support knuckle 16. By way of example, an elastomeric bushing 48 is positioned on either side of the rear transverse link 30.

The end of the tie rod 46 is threaded and passes through an aper¬ ture in the rear transverse link 30 slightly larger than the diameter of the tie rod 46. It is possible that for some applica¬ tions the tie rod can be anchored in a rigid fashion. A nut 50 is threadably engaged with the end of the tie rod 46. The tie rod 46 is positioned so that its shaft portion passes through an aperture 52 in the front transverse link 38. The forward and inboard end of the tie rod 46 is attached to a bracket 54 which, in turn, is anchored to the vehicle. The forward and inboard end of the tie rod 46 is cushioned on both sides of the bracket 54 by means of elastomeric bushings 48. The tie rod 46 is attached to the bracket 54 by a threaded rod end and nut 56, or if desired by a rigid attachment fixture (not shown) .

The spacing of the front and rear transverse links 38 and 30 coupled with the strategically located tie rod 46 with its adjustment capability at each end maintain the required rigidity to produce a slight rear toe-in under heavy cornering and rearward loads. The adjustment afforded by the tie rod 46 and front trans¬ verse link 38 of the present invention permits tuning of the roll steer and the anti-lift angle which are not as readily achievable when a more rigid stamped one-piece lower control arm is used. The present invention, which utilizes an internally positioned trailing link herein defined as a stabilizer member or a tie rod, not only permits the vehicular rear suspension to be assembled in modular form, but also helps the vehicle manufacturer satisfy noise, vibration and handling characteristics of the vehicle.

As shown in Figure 1, the tie rod 46 has its inboard end attached to the bracket 54. The tie rod 46 need not terminate at the bracket 54, but can be extended across the vehicle centerline and be joined as a unitary structure with a similar tie rod for the right-hand vehicular rear wheel. In this manner, an anti-roll bar is created that acts in unison with both rear wheel suspension assemblies. Figure 2 is a partly sectioned perspective view of an embodiment of the overall wheel assembly shown in Figure 1. The support knuckle 16 carries the wheel spindle 18 and the telescopic shock strut 22 or other location device, however, they have been partially omitted in Figure 2 for the sake of clarity. The rear transverse link 30 is attached to the support knuckle 16 by the fastener 32. The inboard end 34 of the rear transverse link 30 is equipped with the bushing 36 in order to facilitate a resilient to the vehicular chassis. The transversely aligned leaf spring 24 has its spring end 26 in contact with the bridge portion 27 of the support knuckle 16. The leaf spring 24 is attached at its central region to the vehicle chassis. The front transverse link 38 is attached to the support knuckle 16 by the fastener 40. The inboard end 42 of the front transverse link 38 is provided with the bushing 44 contained within an aperture formed in the end 42. A central section 58 of the front transverse link 38 is bowed in a downward direction.

The tie rod 46 is attached near the outboard end of the rear transverse link 30 and the elastomeric bushing 48 is posi¬ tioned on either side of the rear transverse link 30. The rear- ward end of the tie rod 46 is threaded and passes through an aperture in the rear transverse link 30 slightly larger than the diameter of the tie rod 46. The nut 50 is threadably engaged wi the end of the tie rod 46. As an alternative coupling, the elastomeric bushing 48 can be eliminated and a more rigid connec tion can be made between the rear transverse link 30 and the tie rod 46. The tie rod 46 is positioned so that its shaft passes over the top of the front transverse link 38 in the vicinity of the bowed down central section 58 of the front transverse link 3 The tie rod 46 has an upwardly disposed curved section 60 that permits the tie rod 46 to remain in an essentially horizontal attitude as it passes over the front transverse link 38. The fo ward and inboard end of the tie rod 46 is attached to the bracke 54 which, in turn, is anchored to the vehicle. The forward end the tie rod 46 is cushioned on both sides of the bracket 54 by means of the elastomeric bushings 48. The tie rod 46 is attache to the bracket 54 by the threaded rod end and the nut 56. The t rod 46 depicted in Figure 2 becomes advantageous from a subassembly standpoint, particularly when the tie rods from both rear wheel suspension assemblies 10 are united to form a single anti-roll bar. The anti-roll bar can be laid over the tops of t front trans verse links 38 without the necessity of threading the anti-roll bar through the apertures 52 in the front transverse links 38.

Figure 3 is a broken away partly sectioned view taken along the lines 3-3 of Figure 2, wherein the rear transverse link 30 is shown in a horizontal attitude. An aperture 62 is posi¬ tioned through the rear transverse link 30 to accommodate the tie rod 46. The aperture 62 is rectangular or square in configuration so as to permit a similarly configured section of the end of the tie rod 46 to pass therethrough. In this manner, the tie rod 46 is prevented from rotation during use. Rotation of the tie rod 46 from its originally installed position with its curved section 60 positioned in an upward attitude would permit the tie rod 46 to contact the front transverse link 38 in the cross over area. While the contacting of the tie rod 46 and the front transverse link 38 would not be necessarily structurally hazardous, such con¬ tact could possibly cause undesired noise that would be audible from within the vehicle.

Figure 4 is a plan view of an embodiment of the present invention that depicts continuity between the tie rods 46 as pre¬ viously commented upon. Figure 4 shows a stabilizer member such as an anti-roll bar 64 with curved sections 60 located on each leg thereof for clearance of the front transverse links 38 of the left and right overall wheel assemblies 10. The cantilevered ends of the anti-roll bar 64 are resiliently anchored to the rear trans¬ verse links 30 as previously set forth. The central section of the anti-roll bar 64 is secured to the vehicle chassis by a hat sectioned bracket 66 that will immobilize the central section of the anti-roll bar 64 yet permit torque loading to pass therethrough. The hat section bracket 66 is secured to the vehicle chassis by fasteners, such as bolts 68. Figure 5 is a broken away partly sectioned perspective view of another embodiment of the present invention. The support knuckle 16 has attached thereto the wheel spindle 18, as shown in Figure 1, and the shock strut 22 or other positioning device. The rear transverse link 30 is attached to the wheel support knuckle 16 by an appropriate fastener such as the fastener 32. The inboard end 34 of the rear transverse link 30 has the bushing 36 therethrough to accommodate a resilient coupling to the vehicular chassis. The bushing 36 lies about an axis 70 that is generally in the fore and aft direction of the vehicle. The transversely aligned leaf spring 24 has its outboard end 26 in contact with the bridge portion 28 of the wheel support knuckle 16. The leaf spring 24 is attached resiliently or rigidly at its central sec¬ tion to the vehicle chassis. The front transverse link 38 is attached to the wheel support knuckle 16 by the fastener 40. The inboard end 42 of the front transverse link 38 is provided with the bushing 44 contained within an aperture that passes through the end 42. The bushing 44 lies about an axis 72 that is not coincident with the axis 70 of the bushing 36. The axes 70 and 72 are parallel to one another and are also parallel to the fore and aft directions of the vehicle. tie rod 74 is attached to the wheel support knuckle 16 by the fastener 40. The actual coupling of the outboard ends of the front transverse link 38 and the tie rod 74 can be rigid or an elastomeric bushing (not shown) can be positioned therebetween. The inboard or forward end 76 of the tie rod 74 is apertured and contains a fastener 78 therethrough that is oriented in a generally vertical attitude. The fastener 78 is utilized to anchor the forward end 76 of the tie rod 74 to a bracket 80, or in the alternative, to the vehicle chassis proper. The above set forth configuration eliminates material in the wheel support knuckle 16 and in the extra bushings that would be required if the outboard end of the tie rod 74 was connected at a location other than with the outboard end of the front trans- verse link 38. The present configuration of the tie rod 74 is augmented by a transverse leaf spring 24 that is positioned bet¬ ween the front and rear transverse links 38 and 30 thus providing a low profile assembly. Also, as shown, the inboard end 76 of the tie rod 74 is oriented along a vertically aligned axis 82 for ease of installation to the vehicle or to a simple bracket, such as the bracket 80 attached thereto. The rotation of the tie rod 74 is less than for a pure trailing link, thus, a tight bushing may be employed along with the fastener 78. The above described embodi¬ ment permits enhanced riding comfort by a low suspension rate in the longitudinal or recession direction, thus shock loads caused by road faults are cushioned. Ideally, the rear wheel should remain straight or toe inward very slightly with rear wheel move¬ ment. The above set forth embodiment utilizes the longitudinal load, caused, for example, by a bump impact, to pull on the tie rod 74 which then rotates about the axis 82 and causes in turn a compression of the bushing 44 radially. Hence, the forward sec¬ tion of the wheel support knuckle 16 is drawn inward relative to the rear transverse link 30 which undergoes little or no load in this case. Therefore, a controlled angle of toe-in may be achieved. In the ride motion, the required steer is provided by the rear transverse link 30 which has the axis 70 of its inward end 34 offset from the axis 72 of the inward end 42 of the front transverse link 38.

Figure 6 is a broken away perspective view of yet another embodiment of a wheel suspension system. As has been shown elsewhere, the wheel support knuckle 16 has attached thereto a wheel spindle 18. The top of the wheei support knuckle 16 is attached to an upper control arm 84 by a bolt 86. The upper control arm 84 is transversely oriented and is attached to a sub- frame 88 by fasteners such as bolts 90. The sub-frame 88 is U- shaped in configuration and extends transversely across the vehicle body. The rear transverse link 30 is attached to the wheel support knuckle 16 by the fastener or bolt 32. The inboard end of the rear transverse link 30 is attached to the sub-frame 88 by the bolt 92. The front transverse link 38 is also attached to the wheel support knuckle 16 by a fastener (not shown) . The inboard end of the front transverse link 38 is attached to the sub-frame 88 by means of a bolt 94. The axes of the bolts 92 and 94 are parallel to the overall longitudinal axis of the vehicle. The axes of the bolts 92 and 94 can be coincident or, if desired, the axes can be offset and parallel to one another. The tie rod 46 has its outboard end attached to the rear transverse link 30 by a nut 50 which also acts to compress the bushing 48 which surrounds the end of the tie rod 46. The tie rod 46 is oriented diagonally with respect to the front and rear transverse links 38 and 30. The inboard end of the tie rod 46 is attached to the sub- frame 88 by a nut and bushing combination similar to the outboard attachment of the tie rod 46. The tie rod 46 passes through the aperture 52 in the front transverse link 38. In order to react the mass of the vehicle, the leaf spring 24 is oriented in a transverse direction and has its spring end 26 biased against the wheel support knuckle 16. The leaf spring 24 can be attached to the sub-frame 88 or directly to the chassis of the vehicle. By attaching the leaf spring 24 to the sub-frame, the entire wheel support system can be installed on a vehicle in a minimum of time. The leaf spring 24 has a tically oriented contour 96 as it passes over the tie rod 46. curvature of the leaf spring 24 in the vicinity of the wheel suport knuckle 16 avoids any scuffing of the surface of the l spring 24 because of vertical movement of the vehicle wheel. attachment of the leaf spring 24 to either the sub-frame 88 or vehicle chassis can be adjusted in the vertical direction so the spring end 26 always remains parallel to its bearing surf at the wheel support knuckle 16. The vertical adjustment of t leaf spring 24 can be effected by raising or lowering the posi of the spring mounting member 102 or by inboard or outboard adjustment thereof. Also, the vertically oriented contour 96 the leaf spring 24 permits some flexture in the transverse dir tion thus matching the movement of the wheel support knuckle 1 it moves arcuately about the axis defined by the bolts 92 and The vertically oriented contour 96 also helps to distribute an torque loading that may be encountered by the leaf spring 24.

In order to attenuate vertical movement of the wheel support knuckle 16 and its attached wheel, the telescopic shoc strut 22 is provided. The telescopic shock strut 22 is shown attached to the front transverse link 38 by a bolt 98. The telescopic shock strut 22 could equally well be attached to th wheel support knuckle 16.

The just described rear suspension system for a vehi provides independent rear suspension for each wheel that is attached to the wheel spindle i8. The sub-frame 88 is attache the vehicle chassis by bolts (not shown) which pass through th mounting holes 100. In those instances when the leaf spring 2 attached to the sub-frame, the entire rear wheel suspension sy can be readily coupled to the vehicle chassis by the installat of bolts through mounting holes 100. The rear wheel suspension assembly depicted in Figure 6 not only lends itself to rapid assembly with the vehicle, but also, the compactness of the assembly requires a miniumum of space beneath the vehicle.

OPERATION AND ASSEMBLY

During the installation of the overall wheel assemblies 10, the internally positioned tie rod 46 helps to support the front and rear transverse links 38 and 30 and the leaf spring 24 as a modular unit. The entire right and left wheel assemblies 10 can be moved into fastening position without undue time consump¬ tion. Also, in those instances where an anti-roll bar 64 is incorporated into the structure it, too, provides assistance along with the leaf spring 24 in coupling the right and left rear wheel assemblies 10 together for ease and speed of assembly to the vehicle chassis.

The operational characteristics of the present invention helps the vehicle manufacturer to meet the objectives of reducing noise and vibration while enhancing the handling of the vehicle. The concept of a compact pair of transverse links coupled with an internally positioned trailing link or tie rod 46, permits the wheel 20 to undergo recession wherein the first increment of the rearward movement is very soft. Additional rearward movement is encountered with a progressively rising rate of resistance to cushion severe shocks and prevent excessive displacements upon braking the vehicle. In order to set forth the preferred embodi¬ ments of the invention, a unitary leaf spring has been illustrated. The invention would work equally well with indepen¬ dent coil spring suspension at each wheel location. While the present invention has been described in terms of a motor powered vehicle, the suspension concept would apply equally well to trailers or semi-trailers. It should be understood that the present invention is not limited to the foregoing embodiments, and that changes and modifications can be readily made by one skilled in the art without departing from the scope of the claims appended hereto.

What is claimed is:

Claims

1. A vehicle wheel suspension structure that controls the amount of movement of a wheel mounted on said vehicle compri¬ sing: a plurality of transversely extending link means pivotally connected at one end to a wheel support knuckle and at an opposite end to the sprung mass of said vehicle; spring biasing means attached to said sprung mass of said vehicle and cooperating with said plurality of transver¬ sely extending link means to attenuate the vertical movement of a portion of the unsprung mass of said vehicle; shock absorber means pivotally connected between said unsprung mass and said wheel support knuckle of said vehicle to react loads incurred by said wheel moving over an uneven sur¬ f ce; and a stabilizer member attached at its outboard end to one of said plurality of transversely extending link means and attached at its inboard end to said sprung mass, said stabilizer member assuming an attitude that is diagonal with respect to at least one of said plurality of transversely extending link means.

2. A vehicle wheel suspension structure that controls the amount of movement of a wheei mounted on said vehicle compri¬ sing: a plurality of transversely extending link means pivotally connected in spaced apart relationship at one end to a wheel support knuckle and at an opposite end to the sprung mass of said vehicle; spring biasing means positioned between said plura¬ lity of transversely extending link means and attached to the sprung mass of said vehicle to attenuate the vertical movement of a portion of the unsprung mass of said vehicle; shock absorber means pivotally connected between said unsprung mass and said wheel support knuckle of said vehicle to react loads incurred by said wheel and control said wheel moving over an uneven surface: and a tie rod attached at its outboard end to one said link means and attached at its inboard end to said spru mass, said tie rod traversing said plurality of transversely extending link means and said spring biasing means in a diag 5 attitude.

3. A vehicle wheel suspension structure that con the amount of movement of a wheel mounted on said vehicle co sing: a first transversely extending link pivotally 10 nected to a wheel support knuckle and to the sprung mass of vehicle; a second transversely extending link position spaced apart relationship with respect to said first transve extending link, said second transversely extending link bein 15 pivotally attached to said wheel support knuckle and to the mass of said vehicle; spring biasing means arranged transversely of vehicle and positioned between said first and second transve extending links, said spring biasing means being attached to 20 sprung mass of said vehicle to attenuate the vertical moveme a portion of the unsprung mass of said vehicle; shock absorber means pivotally connected betw said unsprung mass and said wheel support knuckle of said ve to react loads incurred by said wheel moving over an irregul 25 surface; and a stabilizer member attached at its outboard said first transversely extending link and attached at its i end to said sprung mass, said stabilizer member traversing s first and second transversely extending links and said sprin 30 biasing means in a diagonal attitude.

4. A vehicle wheel suspension structure as set f in Claim 3, wherein said spring biasing means is supported o end by bridge means that is formed as a part of said wheel s knuckle.

5. A vehicle wheel suspension structure as set forth in Claim 3. wherein an aperture is positioned in one of said first and second transversely extending links, said aperture positioned in a horizontal attitude and located along the expanse of said one transversely extending link between the ends thereof to accom¬ modate the passage of said stabilizer member therethrough.

6. A vehicle wheel suspension structure as set forth in Claim 5, wherein said aperture is positioned in said first transversely extending link and said stabilizer member is in the form of a tie rod of linear configuration with its outboard end attached to said second transversely extending link and its inboard end attached to said sprung mass, said tie rod being directed diagonally through said aperture in said first transver¬ sely extending link.

7. A vehicle wheel suspension structure as set forth in Claim 3, wherein said stabilizer member traverses diagonally over the top of said spring biasing means and is positioned in juxtaposed relationship to said first transversely extending link without passing therethrough.

8. A vehicle wheel suspension structure as set forth in Claim 7, wherein said stabilizer member is of curvilinear con¬ figuration and has means formed on at least one end thereof to coact with complementary means formed in one of said first and second transversely extending links to prevent said stabilizer member from rotating.

9. A vehicle wheel suspension structure as set forth in Claim 3, wherein said first transversely extending link has a curvilinear portion between its attached ends, said curvilinear portion extending in a downward direction.

10. A vehicle wheel suspension structure as set forth in Claim 3, wherein said stabilizer member is in the form of an anti-roll bar with two ends and a central section attached to said sprung mass, each end of said anti-roll bar being attached to an outboard end of one of said first and second transversely extending links on each side of said vehicle, said anti-roll bar being positioned diagonally with respect to said spring biasing means and said second transversely extending link on each side of said vehicle.

11. A vehicle wheel suspension structure as set forth in Claim 10. wherein said anti-roll bar passes through apertures positioned in said first transversely extending links on each side of said vehicle.

12. A vehicle wheel suspension structure as set forth in Ciaim 11 , wherein said first transversely extending link has a curvilinear portion between its attached ends, said curvilinear portion extending in a downward direction, said anti-roll bar being positioned in juxtaposed position with respect to said cur¬ vilinear portion of said first transversely extending link on both sides of said vehicle.

13. A vehicle wheel suspension structure as set forth in Claim 3, wherein elastomeric cushions are connected to at least one end of said stabilizer member.

14. A vehicle wheel suspension structure as set forth in Claim 3, wherein said stabilizer member is attached adjacent to the outboard end of one of said first and second transversely extending links and assumes a diagonal attitude with respect to said first and second transversely extending links.

15. A vehicle wheel suspension structure as set forth in Claim 14, wherein said tie rod is attached to the outboard end of one of said first and second transversely extending links and assumes a diagonal attitude with respect to said first and second transversely extending links.

16. A vehicle wheel suspension structure that controls the amount of movement of a wheel mounted on said vehicle compri- sing: a plurality of transversely extending link means pivotally connected at one end to a wheel support knuckle and at an opposite end to the sprung mass of said vehicle; spring biasing means attached to the sprung mass of said vehicle and aligned with said plurality of transversely ά<o -

extending link means to attenuate the vertical movement of a por¬ tion of the unsprung mass of said vehicle; shock absorber means pivotally connected between said chassis and said wheel support knuckle of said vehicle to react loads incurred by said wheel moving over an uneven surface; and a stabilizer member attached at its outboard end to one of said plurality of transversely extending link means and attached at its inboard end to said sprung mass, said stabilizer member being attached to at least one of said plurality of trans¬ versely extending link means.

17. A vehicle wheel suspension assembly that controls the amount of movement of a wheel mounted on said assembly compri¬ sing: a plurality of transversely extending link means pivotally connected at one end to a wheel support knuckle and at an opposite end to a sub-frame; spring biasing means attached to said sub-frame and aligned with said plurality of transversely extending link means to attenuate the vertical movement of a portion of said assembly; a stabilizer member attached at its outboard end to one of said plurality of transversely extending link means and attached at its inboard end to said sub-frame, said stabilizer member being in spaced apart relationship with respect to said spring biasing means.

18. A vehicle wheel suspension assembly as set forth in Claim 17, wherein said stabilizer member passes through an aper¬ ture in one of said transversely extending link means.

19. A vehicle wheel suspension assembly as set forth in Claim 17, wherein shock absorber means is pivotally connected to one of said transversely extending link means.

20. A vehicle wheel suspension assembly as set forth in Claim 17, wherein said spring biasing means is arcuately contoured adjacent an end thereof.