US20060046826A1

US20060046826A1 - Automobile racing suspension system

Info

Publication number: US20060046826A1
Application number: US10/925,121
Authority: US
Inventors: Michael Gilmartin
Original assignee: Individual
Current assignee: Individual
Priority date: 2004-08-24
Filing date: 2004-08-24
Publication date: 2006-03-02

Abstract

An automotive racing vehicle suspension system coupled between a vehicle body and a rotatable wheel, the suspension system comprising: an upper wheel assembly control arm coupled at a proximal end to the vehicle body; a lower A-frame portion rigidly suspended at a proximal end below the upper wheel assembly control arm; a vertical link coupled between a distal end of the upper wheel assembly control arm and a distal end of the lower A-frame portion, the vertical link rotatably coupled to a hub assembly; a leaf spring attached to the upper wheel assembly control arm for providing resilient resistance to vertical motion above or below the upper wheel assembly control arm; at least one shock absorber coupled between the chassis and the lower A-frame portion for providing resilient resistance to motion between the upper wheel assembly control arm and the lower A-frame portion which causes a compressive force in the at least one shock absorber; and at least one pull-spring coupled between the upper wheel assembly control arm and the lower A-frame portion for providing resilient resistance to motion between the upper wheel assembly control arm and the lower A-frame portion which causes a tensile force in the at least one pull-spring.

Description

FIELD OF THE INVENTION

The present invention relates generally to automotive suspension systems, and more particularly, to suspension systems for sports and racing cars.

BACKGROUND OF THE INVENTION

Automotive suspension systems 90 of the prior art utilize front and rear springs to suspend the weight of the vehicle. The suspension springs 92 used on typical cars and trucks are constructed in a variety of types, shapes, sizes, rates, and capacities, including leaf springs, coil springs, air springs, and torsion bars. These suspension springs 92 are used in sets of four for each vehicle, or they may be paired off in various combinations and attached by any of several different mounting systems and techniques. As best shown in FIG. 1, common suspension systems 90 of the prior art also contains shock absorbers and/or struts 94, and sway bars. Improvements in suspension and steering, increased strength and durability of components, and advances in tire design and construction have made large contributions to riding comfort and to safe driving.
The suspension system 90 of the prior art has two basic functions, to keep the wheels of a vehicle in firm contact with the road surface and to provide a comfortable ride. One of the key components in a suspension system is springs. Under normal conditions, the springs support the body of the car evenly by compressing and rebounding with every up-and-down movement. This up-and-down movement, however, causes bouncing and swaying after each bump and is very uncomfortable. These undesirable effects are reduced by one or more shock absorbers 94.
However, in the case of racing vehicles that run at high speed which typically utilize pushrod suspension systems, the conditions are very different. At speeds in excess of about 50 miles per hour, the impact is no longer a “push” but a sudden, violent thrust. Of all the methods currently in use to control an un-sprung wheel assembly given vehicle weight, road surface irregularity and lateral forces, the push-rod-to-compression-spring via fulcrum or rocker is the least effective and the most undesirable at speeds in excess of 50 mph. The reason is that the push rod impact first strikes a fulcrum causing a seizure moment on the center pin/pedestal journal. By the time the weakened impact encounters the static coil springs, another surface irregularity is encountered. As a result, the tires are forced to absorb both impacts. This causes undesirable stresses to both vehicle and driver.
The stresses imposed on the vehicle and passengers are difficult to evaluate, they are inevitably harmful to overall structural integrity of the vehicle. In addition, those stresses are exerted at an approximately 45-degree angle to the outer section of the lower A-frame, which contributes to side drift and surface skid of the wheels. This type of situation can be particularly critical in performance of racing vehicles, primarily due to the fact that racing vehicles such as those shown in FIGS. 1 and 2 (PRIOR ART) have a very low center of gravity, thus making them inherently susceptible to side drift and surface skid.
FIG. 1 is a representative schematic view showing a common mechanism 80 of automotive suspension system of the prior art. FIG. 2 is a representative view showing a common assembly of suspension system 90 of racing vehicles of the prior art.
The wheel assemblies are supported by upper and lower ‘A’ shaped arms 88. The entire mechanism is a basic lever system that allows the spindles 86 to travel vertically up and down. When that occurs, they also have a slight side-to-side motion caused by the arc which the levers scribe around their pivot point. This side-to-side motion is known as scrub. Coil springs 82 has as its primary duty to absorb the loads and motion induced by the wheels' encounter with bumps, holes, and uneven surfaces, and to help keep the tires in firm contact with the pavement under a variety of operating condition. It is in the nature of a coil spring 82 to store the energy of the load or shock it absorbs, and then release that energy again by returning to its original shape and size. In practical application, in fact, coil spring 82 will not just return to its relaxed position, but will overshoot that, and continue to oscillate back and forth from a compressed condition to an extended condition through several diminishing cycles until the original energy absorbed is finally dissipated. Shock absorbers 84 which contain hydraulic fluid are motion damping devices that dampens the oscillations of coil springs 82 by expending energy through its own movement.

ADVANTAGES AND SUMMARY OF THE INVENTION

The present invention provides significantly more control of vehicles on wet surfaces, or where aerodynamic down-force or ground effects cannot be effectively utilized. Therefore, mechanical down-force should be maximized where possible, resulting in better cornering, driver control and comfort and minimized jarring, abrupt or otherwise violent wheel flutter on chicanes, curves or track corrugations and/or corrugated surfaces.
The present invention comprises a suspension system with two parallel, helical pull-springs closely coupled to the highest, outermost point of the vertical linkage, having either a left or a right hand coil helix working in unison or sequentially. An object and advantage of the present invention is to provide a mechanism to control or provide greater security of un-sprung wheel assembly and lateral weight transfer.
An object and advantage of the present invention is to keep the tires of high speed vehicles on the road surface for the greatest possible percentage of circuit distance. In airborne wheels which are un-controlled, surface protrusions and bumps in the road are most often the cause of upward vertical travel. Additionally, the forward speed of the vehicle has the natural tendency to lift the wheel assembly. Indentations (“potholes”), depressions at high speeds are encountered on the forward side and are therefore upward thrust. The result is undesirable vertical lift of the assembly and the present invention provides an appropriate intervention required for better and improved control and road handling.
Another object and advantage of the present invention is to prevent high speed vehicles, which have low center of gravity, from side drift and surface skid. The prevent invention provides a counter-balanced stress that is directed at approximately a 45 degree angle to the outer section of the lower A-frame of a vehicle. The stress can be expressed as a vector having comparable magnitude and opposing direction as the forces on the vehicle caused by the road and racing the vehicle at high speeds, around curves, etc.
In a preferred embodiment, the present invention is an automotive racing vehicle suspension system coupled between a vehicle body and a rotatable wheel, the suspension system comprising: an upper wheel assembly control arm coupled at a proximal end to the vehicle body; a lower A-frame portion rigidly suspended at a proximal end below the upper wheel assembly control arm; a vertical link coupled between a distal end of the upper wheel assembly control arm and a distal end of the lower A-frame portion, the vertical link rotatably coupled to a hub assembly; a leaf spring attached to the upper wheel assembly control arm for providing resilient resistance to vertical motion above or below the upper wheel assembly control arm; at least one shock absorber coupled between the chassis and the lower A-frame portion for providing resilient resistance to motion between the upper wheel assembly control arm and the lower A-frame portion which causes a compressive force in the at least one shock absorber; and at least one pull-spring coupled between the upper wheel assembly control arm and the lower A-frame portion for providing resilient resistance to motion between the upper wheel assembly control arm and the lower A-frame portion which causes a tensile force in the at least one pull-spring.
In another preferred embodiment of the present invention, the at least one pull-spring is a helical coil spring.
In another preferred embodiment of the present invention, the at least one pull-spring is an elastic member.
In another preferred embodiment of the present invention, the at least one shock absorber is coupled between the proximal end of the upper wheel assembly control arm and the distal end of the lower A-frame portion.
In another preferred embodiment of the present invention, the at least one pull-spring is coupled between the distal end of the upper wheel assembly control arm and the proximal end of the lower A-frame portion.
In another preferred embodiment of the present invention, the at least one shock absorber is coupled between the distal end of the upper wheel assembly control arm and the proximal end of the lower A-frame portion.
In another preferred embodiment of the present invention, the leaf spring is partial elliptic.
In another preferred embodiment of the present invention, the leaf spring is quarter elliptic.
In another preferred embodiment of the present invention, the leaf spring is slightly arched downward.
In another preferred embodiment of the present invention, the leaf spring comprises plurality of leaf springs attached to the upper wheel assembly control arm for providing resilient resistance to vertical motion above or below the upper wheel assembly control arm.
In another preferred embodiment of the present invention, the at least one pull-spring comprises 2 pull-springs each coupled independently between the distal end of the upper wheel assembly control arm and the chassis.
In another preferred embodiment of the present invention, the 2 pull-springs are opposingly wound helical coil springs which operate sequentially or in unison.
In another preferred embodiment of the present invention, the at least one shock absorber is a hydraulic shock absorber.
In another preferred embodiment of the present invention, the hydraulic shock absorber is active on the upstroke and passive on the return stroke.
In another preferred embodiment of the present invention, a multi-strand cable is attached to the distal end of the lower A-frame for control of the vehicle during braking.
In another preferred embodiment of the present invention, the vertical link separates the distal end of the upper wheel assembly control arm and the distal end of the lower A-frame portion by a distance as close as possible to the outer diameter of the wheels of the vehicle.
In another preferred embodiment of the present invention, the vertical link separates the distal end of the upper wheel assembly control arm and the distal end of the lower A-frame portion by a distance slightly less than the outer diameter of the wheels of the vehicle.
Further objects and advantages of the present invention will be come apparent through the following descriptions, and will be included and incorporated herein.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a representative schematic view showing a common mechanism 80 of automotive suspension system of the prior art.
FIG. 2 is a representative view showing a common assembly of racing vehicles 90 of the prior art.
FIG. 3 is a representative side view of a preferred embodiment of a suspension system 100 of the present invention.
FIG. 4A is a representative side view of a preferred embodiment of a suspension system 100 of the present invention with multi-strand cables 402.
FIG. 4B is a representative side view of a preferred embodiment of an alternative assemble of a suspension system 100 of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The description that follows is presented to enable one skilled in the art to make and use the present invention, and is provided in the context of a particular application and its requirements. Various modifications to the disclosed embodiments will be apparent to those skilled in the art, and the general principals discussed below may be applied to other embodiments and applications without departing from the scope and spirit of the invention. Therefore, the invention is not intended to be limited to the embodiments disclosed, but the invention is to be given the largest possible scope which is consistent with the principals and features described herein.
It will be understood that in the event parts of different embodiments have similar functions or uses, they may have been given similar or identical reference numerals and descriptions. It will be understood that such duplication of reference numerals is intended solely for efficiency and ease of understanding the present invention, and are not to be construed as limiting in any way, or as implying that the various embodiments themselves are identical.
FIG. 3 is a representative side view of a preferred embodiment of a front-wheel suspension system 100 of the present invention. The fundamental of the suspension system 100 is a single or plurality of parallel, helical pull-springs 102. The upper end 103 of pull-springs 102 is closely coupled to the highest, outermost point of vertical link 104. In the plural spring configuration assembly, the pairing of the left and right hand helical pull-springs 102 work either in unison or sequentially. These specifications should be resolved in accordance with weight and dimension requirements, i.e., the tension and duty of the pull-springs 102 are determined based on the actual vehicle weight and dimension configuration. These should provide the swiftest response to ground surface irregularity. The lower ends of the helical pull-springs 102 should be attached to an accessible anchor points 114 on the lower chassis with eccentric adjustment if necessary. The adjustable anchor points 114 allow for infinitely adjustable pull-springs 102 in regard to tension, angle of connection with the upper ends of the pull springs 103 and the upper trunnions 112, offset from the vertical mounts 140 and the lower A-frame portion 116, etc. In the embodiment of twin pull-spring assembly, the spacing Δ between the paring helical pull-springs 102 should be consistent to avoid influence of either under-steer or over-steer.
In a preferred embodiment, a shock absorber 108 is secured diagonally to helical pull-springs 102. The upper end of shock absorber 108 is secured to the chassis frame. The lower end of shock absorber 108 is secured on lower A frame member 116. The main function of shock absorber 108 is to dampen the oscillations of helical pull-springs 102 by expending energy through its own movement. Shock absorbers 108 with different mechanisms could be used to perform the same function. In the embodiment wherein a hydraulic shock absorber 108 is used. Hydraulic shock absorber 108 should be active on the up-stroke and passive on the down-stoke. In the embodiment wherein a friction shock absorber 108 is used, friction shock absorber 108 should be normally inert and made progressively active by the upward movement of the control arm 109 of the shock absorber 108.
Lower A frame 116 is attached to the vertical link 104 by lower swivel trunnion 110. Alloy block spacers or trunnions 110 with provision for vertical and rotary motion of the wheel assembly 101. Multi-directional ball-joints offer little stability or precise assembly control. As best shown in FIG. 3, the vertical link 104 can take the shape and form of two parallel tubes. In a more preferred embodiment, an alloy casting or carbonized acrylic fiber unit may be used. Wheel assembly control arm 126 is attached to the top of vertical link 104 by upper swivel trunnion 112. The structure of upper swivel trunnion 112 is the same as that of lower swivel trunnion 110 except for the presence of hard rubber spacers. The hard rubber spacers separate the upper ends 103 of pull-springs 102 and the upper swivel trunnion 112. Considering the vertical travel of suspension system 100 of racing cars is so limited, it is deemed unnecessary to use a shackle or double-hinged trunnion. Additionally, the hard rubber spacers absorb initial shocks to aid in comfort and smoothness of ride for the driver, thus preventing transfer of shocks through the suspension system 100 of the present invention.
As shown in FIG. 3, a quarter-elliptic transverse single-leaf flat steel spring 118 is attached to the wheel assembly control arm 126. In a preferred embodiment, wheel assembly control arm 126 is slotted 117. The main function of slot 117 is to allow camber adjustment. In a preferred embodiment, the transverse flat steel spring 118 is slightly arched downward, and has a quarter-elliptic shape and configuration. Additional spring leaves may be added depending on resistance required. Transverse flat steel spring 118 also serves as an upper wheel assembly location strut, providing easy camber adjustment and vertical wheel travel limitation. In addition, this also serves as a mainspring, resisting vertical motion in both directions and causing no appreciable restriction in air circulation, wind resistance or aerodynamic interference.
It is of the utmost importance that the vehicle have complete control of the wheel assembly 101 and not vice-versa. Therefore, in a preferred embodiment, the lower A-frame 116 should be attached as closely to the outer perpendicular periphery of the wheel assembly 101 as feasible. This configuration ensures adequate leverage control advantage to the vehicle in directional changes, cornering or when lateral forces are encountered.
As best shown in FIG. 3, lower A-frame 116 and wheel assembly control arm 126 are connected by two vertical mounts 140. It should be emphasized that in a preferred embodiment, vertical mounts 140 can be replaced by applicable mounts or brackets to suit chassis or body structure of the particular vehicles.
Suspension system 100 of present invention can be converted from a front wheel assembly to a rear wheel assembly by repositioning the shock absorber 108. In a preferred embodiment, a pair of shock absorbers 108 can be mounted on the outside of both of lower A-frame 116 and wheel assembly control arm 126 in either the front or rear of the vehicle, or both Shock absorbers 108 can be mounted at position 120 at wheel assembly control arm 126 and position 122 at lower A-frame 116. The alternate arrangement for rear wheel assembly is to accommodate drive axle assembly.
FIG. 4A is a representative side view of a preferred embodiment of a suspension system 100′ of the present invention with multi-strand cables 402. As shown in FIG. 4A, a multi-strand cable 402 is attached to suspension system 100′ of present invention. In a preferred embodiment, the thickness of multi-strand cable 402 should be in the range of 10 mm to 15 mm. Multi-strand cable 402 should be coupled to left and right hand A-frames forward and rearward with some absorption at the front center for control of the very high stresses imposed by braking of the vehicle.
It will be understood that in the suspension system 100′ of the present invention, cable 402 links the wheel assembly vertical links 104 and the two wheels 101 together, at the center of the chassis, in front or at a point intermediate the front of the chassis and the axles 106. This cable 402 enhances rigidity and strength of the suspension system 100′ such as during hard braking, road irregularities, etc. By linking both sides of the lower A-frame 116 through a point on the chassis by the cable 402, enhanced and increased suspension can be achieved.
FIG. 4B is a representative side view of an alternate preferred embodiment of an assembly of a suspension system 100″ of the present invention. In a preferred embodiment, a single combined spring and shock absorber portion 404 replaces the helical pull-springs 102 and shock absorber 108 as best shown in FIG. 3. The assembly 100″ is such that shock absorber 108 is nested in the center of helical pull-spring 102.
The upper end of combined spring 102 is closely coupled to the highest; outermost point of vertical link 104. The vertical link 104 is attached to stub axle 106, which is attached to wheels 101. The lower end of combined spring 102 and shock absorber 404 should be attached to an accessible anchor points 114 on the lower chassis or A-frame 116 with eccentric adjustment if necessary.
With regard to the embodiments shown in FIGS. 3, 4A and 4B, the main function of shock absorber 108 is to dampen the oscillations of helical pull-springs 102 by expending energy through its own movement. Shock absorbers 108 filled with hydraulic fluid, or as otherwise known to those skilled in the art, can be used. In the embodiment wherein a hydraulic shock absorber 108 is used, the hydraulic shock absorber 108 should be active on the up-stroke and passive on the down-stoke.
In practice, friction shock absorbers are seldom if ever used. However, in the embodiment wherein a friction shock absorber 108 is used, friction shock absorber 108 should be normally inert and made progressively active by the upward movement of the control arm 112 of the shock absorber 108.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present invention belongs. Although any methods and materials similar or equivalent to those described can be used in the practice or testing of the present invention, preferred methods and materials are now described. All publications and patent documents referenced in the present invention are incorporated herein by reference.
While the principles of the invention have been made clear in illustrative embodiments, there will be immediately obvious to those skilled in the art many modifications of structure, arrangement, proportions, the elements, materials, and components used in the practice of the invention, and otherwise, which are particularly adapted to specific environments and operative requirements without departing from those principles. The appended claims are intended to cover and embrace any and all such modifications, with the limits only of the true purview, spirit and scope of the invention.

Claims

1. An automotive racing vehicle suspension system coupled between a vehicle body and a rotatable wheel, the suspension system comprising:

an upper wheel assembly control arm coupled at a proximal end to the vehicle body;

a lower A-frame portion rigidly suspended at a proximal end below the upper wheel assembly control arm;

a vertical link coupled between a distal end of the upper wheel assembly control arm and a distal end of the lower A-frame portion, the vertical link rotatably coupled to a hub assembly;

a leaf spring attached to the upper wheel assembly control arm for providing resilient resistance to vertical motion above or below the upper wheel assembly control arm;

at least one shock absorber coupled between the chassis and the lower A-frame portion for providing resilient resistance to motion between the upper wheel assembly control arm and the lower A-frame portion which causes a compressive force in the at least one shock absorber; and

at least one pull-spring coupled between the upper wheel assembly control arm and the lower A-frame portion for providing resilient resistance to motion between the upper wheel assembly control arm and the lower A-frame portion which causes a tensile force in the at least one pull-spring.

2. The suspension system of claim 1 wherein the at least one pull-spring is a helical coil spring.

3. The suspension system of claim 1 wherein the at least one pull-spring is an elastic member.

4. The suspension system of claim 1 wherein the at least one shock absorber is coupled between the proximal end of the upper wheel assembly control arm and the distal end of the lower A-frame portion.

5. The suspension system of claim 1 wherein the at least one pull-spring is coupled between the distal end of the upper wheel assembly control arm and the proximal end of the lower A-frame portion.

6. The suspension system of claim 5 wherein the at least one shock absorber is coupled between the distal end of the upper wheel assembly control arm and the proximal end of the lower A-frame portion.

7. The suspension system of claim 1 wherein the leaf spring is partial elliptic.

8. The suspension system of claim 1 wherein the leaf spring is quarter elliptic.

9. The suspension system of claim 1 wherein the leaf spring is slightly arched downward.

10. The suspension system of claim 1 comprising a plurality of leaf springs attached to the upper wheel assembly control arm for providing resilient resistance to vertical motion above or below the upper wheel assembly control arm.

11. The suspension system of claim 1 wherein the at least one pull-spring comprises 2 pull-springs each coupled independently between the distal end of the upper wheel assembly control arm and the chassis.

12. The suspension system of claim 11 wherein the 2 pull-springs are opposingly wound helical coil springs which operate sequentially or in unison.

13. The suspension system of claim 1 wherein the at least one shock absorber is a hydraulic shock absorber.

14. The suspension system of claim 13 wherein the hydraulic shock absorber is active on the upstroke and passive on the return stroke.

15. The suspension system of claim 1 further comprising a multi-strand cable attached to the distal end of the lower A-frame for control of the vehicle during braking.

16. The suspension system of claim 1 in which the vertical link separates the distal end of the upper wheel assembly control arm and the distal end of the lower A-frame portion by a distance as close as possible to the outer diameter of the wheels of the vehicle.

17. The suspension system of claim 1 in which the vertical link separates the distal end of the upper wheel assembly control arm and the distal end of the lower A-frame portion by a distance slightly less than the outer diameter of the wheels of the vehicle.