CA2300585A1 - Double v-link stabilizing system for air spring suspensions - Google Patents

Abstract

A system for stabilizing the location and attitude of an axle on a vehicle using an air spring suspension is disclosed. A first V-link member, having a first end, a second end and an apex section between its first and second ends, is pivotally attached at each end to opposings ends of the axle and pivotally mounted from the vehicle frame at a point centered between elongated frame rails and displaced from the axle in the direction of elongation of the frame. A second V-link member, having a first end, a second end and an apex section between the first end and the second end, is mounted between the vehicle and the axle by pivotally attaching its first and second ends to the outside frame rail at points displaced from the axle parallel to the direction of elongation of the frame and by a third pivot mount to the center of the axle. The points of attachment of the first V-link member are vertically displaced from the points of attachment of the second V-link member to avoid the attachment points of different V-link members being coaxial with the roll axis of the vehicle.

Description

n~ta rro. D-sass DOUBLE V-LINK STABILIZING SYSTEM
FOR AIR SPRING SUSPENSIONS
BACKGROUND OF THE INVENTION
1. Field of the Invention:
The present invention relates to vehicle suspension systems and, more particularly, to auxiliary axle stabilization for an air spring suspension system. The invention provides for reducing axle lateral deflection and for improving vehicle stability by increasing resistance to reactive brake dive and to vehicle roll.

2. Background:
Truck suspension systems provide isolation of passengers and cargo from road shock while keeping the vehicle stable and preserving operator control. These objectives are met using combinations of springs, motion damping devices and auxiliary axle positioning elements.
Achieving acceptable levels of performance, while supporting the vehicle's weight over a wide range of vehicle load conditions, is preferably achieved with a mechanically simple, compact and light weight suspension system. ' The central element of any suspension system is the spring, and the four most popular, basic types of suspension systems used on trucks are categorized by the spring used, i.e.: leaf spring systems; beam systems; torsion bar systems; and air spring systems. Hybrid combinations of these are also used.
Air spring based systems have recently gained in popularity and have been applied to both steering and non-steering axles as well as driven and undriven axles. In an air spring based system, air bellows are positioned with respect to an axle and a vehicle frame to support the frame from the axle. Air spring suspensions give excellent load and vibration isolation by eliminating the interleaf friction found in traditional multiple leaf spring designs and, in some systems, by allowing active Doclca No. D-.1886 control of the spring rate. In addition, an air spring usually has a lower deflection rate than a lei spring exerting the same force, giving the system greater capacity for absorbing shocks for a given displacement between the axle and the frame. Air spring pressure can be adjusted to compensate for vehicle load changes by adding air to or exhausting air from the spring. This aspect of the springs also benefits other suspension design objects, since by adding or exhausting air the vehicle height need not vary with load or positioning of the load.
A drawback of nonhybrid air spring suspension systems, especially when compared with leaf spring systems, is that they require more auxiliary stabilization to maintain the proper location and attitude of the axle with respect to the vehicle and to prevent excessive vehicle roll. Absent stabilization, air springs will extend to their maximum lengths or widths in the direction of least resistance and can cause an unevenly loaded vehicle to fall over to one side, while leaf springs, because of twin points of connection to the vehicle frame both fore and aft of the axle, are partially self stabilizing and provide better directed support.
Auxiliary stabilization may be directed to controlling one or more specific types of undesired movement of a vehicle or axle. To some extent, the control of one type of movement may be more readily accomplished by trading off control of another type of movement. Some auxiliary stabilizing elements can even promote certain types of undesired vehicle body or axle movement while achieving control of some other movement. Among the problems to be controlled are vehicle roll occurring during cornering, suspension compression (front end dive) occurring on braking, suspension expansion adjacent a driven axle on acceleration (acceleration lift), and lateral deflection of the axle, particulalry during turning. Some auxiliary stabilizing systems produce axle caster changes with vertical motion of an axle.
Where air springs are used and an auxiliary stabilization system is applied to a steering axle, additional complications are presented. For a steering axle, as air spring is usually placed adjacent each wheel and over the axle, directly below the side rails of the vehicle frame. In attaching components of the auxiliary stabilization system, the position of the steering pitman and connecting link must be taken into account. Lateral deflecting forces, while a concern with any axle, will be particularly strong, and the consequent possibility of suspension steering more likely.

Deckcc No. D-a886 Parallelogram auxiliary stabilizing systems have been used as auxiliary stabilizing systems in recent air spring suspension designs. Parallelogram systems solve a number of problems, but do not provide any inherent stabilization against body roll and do not provide lateral stabilization of axles. Additional stabilizing elements, adding both weight and complexity, have been required with parallelogram systems. In addition, while parallelogram systems attached to each end of an axle can prevent castor change of the axle, they require heavy and bulky mounting braces connected to the axle, which also add weight to the vehicle and, in some cases, reduce the available room for mounting of the air spring. Parallelogram systems are neutral respecting any response to reactive brake forces, in that they neither contribute to nor prevent front end dive or acceleration related rise of a vehicle.
Countering some or all of all these problems is preferably obtained with a system which is not excessively complex, bulky or heavy, which allows the full capacity of the air springs to be utilized.
SUMMAI~tY OF THE INVENTION
It is an object of the invention to provide auxiliary axle stabilization for an air spring suspension system characterized by improved vehicle stability.
It is a further object of the invention to provide an air spring suspension system having improved resistance to roll.
It is another object of the invention to provide a suspension system which enhances steering axle lateral stability without use of a track bar.
The foregoing objects and others are achieved as is now described. The invention provides a system for stabilizing the location and attitude of an axle on a vehicle using an air spring suspension. A first V-link member having first and second opposing ends and an apex section between its first and second ends is pivotally attached by its opposing ends to opposing ends of the axle and is further pivotally mounted by the apex section to the vehicle frame at a point centered Docket No. D-tH86 between the elongated frame rails and displaced from the axle along the direction of elongation of the frame. A second V-link member having first and second opposing ends and an apex section between the first end and the second end is mounted between the vehicle and the axle by pivotally attaching its first and second ends to the outside frame rail at points displaced from the axle along the direction of elongation of the frame and by a third pivot mount connecting the apex section and the center of the axle. The points of attachment of the first V-link member are vertically displaced from the points of attachment of the second V-link member, avoiding the attachment points of different V-link members being simultaneously coaxial with the roll axis of the vehicle.
Additional effects, features and advantages will be apparent in the written description that follows.
BRIEF DESCRIPTION OF THE DRAWINGS
The novel features believed characteristic of the invention are set forth in the appended claims. The invention itself however, as well as a preferred mode of use, further objects and advantages thereof, will best be understood by reference to the following detailed description of an illustrative embodiment when read in conjunction with the accompanying drawings, wherein:
Fig. 1 is a bottom perspective view of an embodiment of the suspension stabilizing system of the invention used with a steering axle of a truck;
Fig. 2 is a partial side elevation view of the embodiment of Fig. 1;
Fig. 3 is a bottom perspective view of a second embodiment of the suspension stabilizing system applied to tandem drive axles of a truck;
Fig. 4 is a top perspective view of a second embodiment of the suspension stabilizing system applied to tandem drive axles of a truck; and Fig. 5 is a partial side elevation and cutaway of the suspension stabilizing system of Fig. 3.

l7adca No. D-1886 DETAILED DESCRIPTION OF THE Ii~"4'ENTION
Figs. 1 and 2 illustrate a double V-link member axle stabilizing system 11 installed under a portion of a vehicle frame 10. Frame 10 is supported by a suspension system positioned between the vehicle frame and a steering axle 12. While a preferred embodiment of the invention is illustrated used with an air spring suspension, it is not limited to use with air springs and may also be effectively employed with coil springs or other spring systems. The preferred embodiment of the invention is also illustrated as used with a vehicle having a conventional frame, however it is equally applicable to vehicles constructed using a space frame or a unibody vehicle.
Air springs 18 and 20 are positioned directly above and supported on steering axle 12, substantially adjacent the opposed ends of the steering axle, and directly beneath elongated side rails 24 and 26 of vehicle frame 10 to support frame 10 from the axle. A steering gear box 20 is positioned on left side rail 24 forward from steering axle 12. A pitman and trailing link are usually associated with gear box 20 and link it to the vehicle wheel 21 but are not shown for the sake of clarity. A steering tie rod 22 connects wheels 21 and 23, which are mounted on opposed ends of axle 12. Frame 10 fiuther includes a cross member 28 positioned between the left side and right side rail members 24 and 26 to positionally support the rail members and to provide an attachment point for a lower V-link member 42.
Auxiliary suspension stabilization is provided by the double V-link member system 11 which comprises two stacked, oppositely oriented V-link members 32 and 42. An upper V-link member 32 is mounted at three, triangularly arranged points between frame 10 and steering axle 12, with one point being on steering axle 12 and the remaining two points being on frame 10, along left side and right side of frame rails 24 and 26. V-link member 32 is attached to frame 10 at the opposed ends of V-link member, which terminate in sleeves 35 and 36, and to axle 12 along an apex section 31 of the V-link member. Apex section 31 is pivotally enclosed in a sleeve member 30 which depends from and is rigidly attached to steering axle 12 by any appropriate mounting system. Apex section 31 pivots in a sleeve 30 centered on axle 12. The three mounting points of V-link member 32 are positioned at the vertices of a regular triangle.

nocra.No. D-1886 Sleeves 35 and 36 of V-link member 32 are pivotally supported on rods (not shown) set in mounting brackets 37 and 38 which in turn depend, respectively, from leR side frame rail 24 and right side elongated firame rail 26. Brackets 37 and 38 hang from frame rails 24 and 26 respectively, at a position forward from air springs 18 and 20. Accordingly, upper V-link member 32 is disposed as a trailing link from frame 10 to axle 12 and open toward the forward end of the vehicle.
Lower V-link member 42 is positioned directly below V-link member 32. V-link member 42, like V-link member 32, is supported at three points distributed between frame 10 and steering axle 12 and which lie at the vertices of a regular triangle. V-link member 42 is supported at two points along steering axle 12 and at a single point with respect to frame 10.
The points of connection for V-link member 42 lie in a plane below the plane of the points of connection for V-link member 32. Apex section 41 of V-link member 42 is pivotally mounted in a sleeve 43 which rigidly depends from a block 44, which is in turn attached to cross member 28. Block 44 is braced against frame rails 24 and 26 by rods 50 and 52. The opposed ends of V-link member 42 terminate in sleeves 45 and 46. Sleeves 45 and 46 are pivotally attached in bushings 47 and 48 which are inwardly canted toward the centerline of the vehicle along the direction of elongation and tolerate any conicity introduced by the canted position.
Although more than one pivotal mount may be established over a broad apex area, a V-link member which is straightened to allow such connections and is supported at more than one point between the ends of the V-link member begins to resemble a stabilizer bar in function.
Sleeve mount 30 for apex section 31 of upper V-link member 32 is positioned along the upper side axle 12, whereas brackets 47 and 48 which support the sleeve endings 45 and 46 of the lower V-link member 42 are positioned along the lower side of steering axle 12. The three attachment points on axle 12 are thus positioned at the vertices of yet another regular triangle, with the points of attachment being distributed above and below the axle. The three points of support provide substantial lateral stability and longitudinal stability. The vertical offset of the V-link apex joints from one another prevent both points from simultaneously lying on the roll axis of the vehicle, giving good roll resistance. Support at both the upper and lower portions of the axle substantially prevents caster change with vertical travel of the axle 12.

Doctor No. D-48H6 The support points for the opposed ends of the upper V-{ink member 32 and of the apex section 41 of the lower V-link member 42 also lie at the vertices of a triangle, but with a reverse orientation from that of the mounting points on steering axle 12. This gives steering axle 12 two slightly offset axes of rotation during vertical travel, helping prevent caster change of the axle .
Particular reference to Fig. 2 illustrates that while lower V-link member 42 lies substantially flat, that is horizontal with respect to the vehicle, upper V-link member 32 is upwardly canted from apex sleeve 30 toward mounts 37 and 38. V link member 32 may be given an upward cant from axle 12 forward whenever a trailing link configuration is used. This geometry allows transfer of torque reaction from braking as an upward force onto frame rails 24 and 26 to counter front end dive during braking. This orientation is not used where a V-link member is used in a leading configuration or oa an axle positioned away from the forward part of the vehicle. A shock absorber 62 positioned behind air spring 18 dampens axle 12 motion.
Figs. 3-5 illustrate a second embodiment of the invention applied to tandem rear drive axles of a truck Tandem drive axles 64 and 66 support frame 10, along left elongated side rail 24 and right elongated side rail 26, on four air springs 75. Two auxiliary suspension stabilization subsystems 72 and 74 are provided, with auxiliary stabilisation system 72 operating to stabilize axle 64 and auxiliary stabilization system 74 operating to stabilize axle 66.
Stabilization system 72 is oriented as a leading configuration while stabilization subsystem 74 is oriented in a trailing configuration.
Each of the auxiliary stabilization systems 72 and 74 comprises an upper and lower V-link, upper V-Link 80 and lower V-link 82 being in stabilization system 72 and upper V-link member 84 and lower V-link member 86 being in stabilization system 74.
Each of V-link members 80, 82, 84 and 86 is attached between vehicle frame 10 and one of axies 64 and 66 at each of three points. The attachment points on the V-link members are at the opposed ends of the V-link members sad the apex section of each V-link member.
With two V-link members per axle, the mounting points on frame 10 and on axle are distributed so that three are provided on the axle and three are provided fixed with respect to the frame.
For tandem rear axles 64 and 66 this means that there are three attachment points on axle 64, three on axle 66 and a total Docks No. D-1886 of six on frame 10. Between axles 64 and 66, and depending from frame 10, are three inverted pylons 76, 77 and 67. Hollow pylons 76 and 77 are mounted from rails 24 and 26 respectively, and each provide two pivoting connection points. V-link members 82 and 86 are pivotally attached at their opposing ends to inverted pylons 76 and 77. Inverted pylon 67, which depends from a frame cross member 69, provides pivot mounting for apex section of upper V-link members 80 and 84.
Upper V-link member 80 of forward auxiliary stabilization system 72 is connected by pivoting mounts 90 and 91 to opposed ends of axle 64. Upper V-link member 80 is further connected by a pivoting joint 93 along its apex to inverted pylon 67 which depends from cross member 69 between exterior elongated side rails 24 and 26. Lower V-link member 82 is connected by a pivoting mount 94 at the bottom of differential 68 and to the bottom of inverted pylon 76 and 77 by pivoting links 96 and 95 respectively.
The aft auxiliary stabilization subsystem 74 is similarly connected to axle 66. There are six connections between auxiliary stabilization system 74 and frame 10 and axle 66 with three points of connection on each. Upper V-link member 84 of aft stabilization system 74 is connected along its apex to inverted pylon 67 via pivoting member 113 and each end thereof by pivoting mounts, including pivoting mount 97, to axle 66. A lower V-link member 86 is pivotally attached at its apex section to differential 70 by pivoting joint 117 and by pivot mounts 99 and 119 to the bottoms of inverted pylons 74 and 76 respectively.
The invention provides improved vehicle stability by providing for increased resistance to front end dive on braking, improved resistance to roll, good axle lateral stability without the use of a track bar and substantially prevents caster change of an axle during vertical travel. The use of tubular V-link members and the ability to displace stabilizer bars, track bars and heavy motion restraining frames reduces weight over the prior art.
While the invention is shown in only one of its forms, it is not thus limited but is susceptible to various changes and modifications without departing from the spirit and scope of the invention.

Claims (12)

1. Apparatus for stabilizing an axle on a vehicle, comprising:
spring means positioned to support the vehicle from the axle;
a first V-link member having a first end, a second end and an apex section between the first end and the second end;
a second V-link member having a first end, a second end and an apex section between the first end and the second end;
first V-link mounting means for pivotally attaching the first and second ends of the first V-Link member to the axle toward opposed ends thereof, and for pivotally attaching the apex section of the first V-link member to a section of the vehicle longitudinally displaced from the axle and between the opposed ends of the axle; and second V-link mounting means for pivotally attaching the first and second ends of the second V-link member to mutually spaced points on the vehicle, each of the points being longitudinally displaced from the axle, and for pivotally attaching the apex section of the second V-link member to the axle between the opposed ends of the axle.

2. Apparatus for stabilizing an axle on a vehicle as set forth in Claim l, further comprising:
the first V-link member and the second V-link member being disposed to one side of the axle.

3. Apparatus for stabilizing an axle on a vehicle as set forth in Claim 2, wherein:

the second V-link mounting means comprises first, second and third pivot mounts, the first and second pivot mounts connecting the second V-link to an underside of the vehicle, and the third pivot mount connecting the first V-link member to the axle;
the first V-link mounting means comprises first, second and third pivot mounts, the first and second pivot mounts connecting the first V-link and the axle and the third pivot mount connecting the first V-link to the underside of the vehicle; and the first and second pivot mounts of the first V-link mounting means are positioned below the third pivot mount of the second V-link mounting means and the third pivot mount of the first V-link mounting means is position below the first and second pivot mounts of the second V-link mounting means.

4. Apparatus for stabilizing an axle on a vehicle as set forth in Claim 3, further comprising:
the axle being a steering axle; and the second V-link being canted so that its apex section is higher than the first and second ends thereof.

5. Apparatus for stabilizing an axle on a vehicle as set forth in Claim 3, wherein the first and second V-link members are each tubular sections of selected gauges.

6. Apparatus for stabilizing an axle on a vehicle as set forth in Claim 3, wherein the first and second V-link members are arranged as trailing links.

7. Apparatus for stabilizing an axle on a vehicle as set forth in Claim 3, wherein the first and second V-link members are arranged as leading links.

8. Apparatus for stabilizing an axle on a vehicle as set forth in Claim 3, wherein the spring means further comprises first and second air springs, with the first air spring positioned above the axle to support the vehicle from adjacent one end of the axle and the second spring is positioned above the axle to the support the vehicle from adjacent the opposed end of the axle.

9. An axle location and attitude stabilizing system for a vehicle, comprising:
first, second and third axle brace points positionally fixed with respect to the axle, the first and second axle brace points being located toward opposed ends of the axle and defining a parallel line to the axle with the third axle brace point being vertically displaced from the parallel line and centered between the first and second axle brace points;
first, second and third vehicle brace points positionally fixed with respect to the vehicle and displaced from the axle along a direction of elongation of the vehicle, the first and second vehicle brace points being located toward opposed sides of the vehicle and defining a perpendicular line to the direction of elongation of the vehicle, with the third vehicle brace point being vertically displaced from the perpendicular line and substantially centered between the first and second vehicle brace points;
first resilient linkage means for connecting the third axle brace point with the first and second vehicle brace points; and second resilient linkage means for connecting the third vehicle brace point with the first and second axle brace points.

10. An axle location and attitude stabilizing system for a vehicle as set forth in Claim 9, wherein:
the first and second resilient linkage means are tubular V-link members.

11. An axle location and attitude stabilizing system for a vehicle as set forth in Claim 10, further comprising:
the axle being a steering axle;
the first and second resilient linkage means being disposed as trailing links from the vehicle to the axle; and one of the resilient linkage means being canted to rise from its connection to the axle to its connection to the vehicle.

12. An axle location and attitude stabilizing system for a vehicle as set forth in Claim 9, further comprising:
pivoting mounts providing the connections between the resilient linkage means and the vehicle and axle brace points.