Patent Application
20100059958
The present disclosure relates to sway bars. More particularly, the present invention relates to a sway bar which includes a redundancy or backup safety feature.
The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
Sway bars or anti-roll bars are used in vehicles to adjust the torque of the suspension which then influences the roll rate. Sway bars are typically torsional springs which act across an axle to introduce resistance to relative changes in the displacement of one wheel on the axle compared to the displacement of the other wheel on the same axle. The sway bar or torsion spring is constrained both radially and axially and it is connected to the suspension member by a lever arm or by a linkage. The torsional spring rate or the sway bar contributes to the roll stiffness for the vehicle.
Roll stiffness is important to both the ride comfort and the cornering ability of the vehicle. Too little roll stiffness results in excess body roll or lean and slow response to the rotation of the steering wheel by the driver. On the other hand, too much roll stiffness creates an uncomfortable ride and can cause a sudden loss of traction and the ability of the tires to stick to the road during cornering maneuvers.
Sway bars are increasingly being required to withstand higher loads and stresses. Sway bars are typically formed from a bar or a tube having a generally circular cross-section. The bar is bent into the required shape to form arm sections and to fit and function in the particular vehicle application. Multi-piece sway bars are also known where a central bar is attached to a pair of spring elements or arm sections by welding or other means known in the art. The ends of the arm section of the sway bar connect to each end of the axle near the wheel typically with the bushings, ball joints, prop links or other methods known in the art. The center section is attached to the vehicle frame or other support structure using pivot connections.
The present disclosure provides a sway bar which has a redundancy (fail safe) or backup feature to hold the sway bar together should a component fail at a position outside the pivot connections for the center section. In the prior art, if a failure occurs in the position outside the pivot connections, the result is a complete loss of function of the sway bar and partial loss of axle stability typically requiring the immediate removal of the vehicle from service. The redundant or backup feature of the present disclosure will provide a limited function of the sway bar allowing the vehicle to continue to be driven prior to replacement or repair of the sway bar.
Further areas of applicability will become apparent from the description provided herein. The description and specific examples in this summary are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure.
The drawings described herein are for illustrative purposes only of selected embodiments and not all possible implementations, and are not intended to limit the scope of the present disclosure.
The following description is merely exemplary in nature and is not intended to limit the patent disclosure, application or uses.
Referring now to the drawings in which like reference numerals designate like or corresponding parts throughout the several views, there is illustrated in
Frame or support member 12 supports a fifth-wheel 30 which is utilized for the attachment of a trailer or other component to a cab (not illustrated) also supported by frame or support member 12. Each axle assembly 14 supports a plurality of road wheels 32 as is well known in the art. Frame or support member 12 is attached to each of the axle assemblies 14 using four springs 16. Springs 16 are illustrated as air springs but is within the scope of the present disclosure to utilize any type of spring in suspension system 10. A pair of shock absorbers 18 extend between frame or support member 12 and each axle assembly 14 to dampen the motion between frame or support member 12 and axle assembly 14.
Each sway bar assembly 20 is attached between a respective axle assembly 14 and frame support member 12. As illustrated in
Referring now to
Each inner solid rod 42 is attached at one end to a respective bushing assembly 40 and its opposite end extends through mounting bracket 34 such that mounting bracket 34 supports the end of inner solid rod 42. While inner solid rod 42 is illustrated as a solid rod, inner solid rod 42 can also be a tubular rod. Also, while sway bar assembly 20 is being illustrated as having two identical inner solid rods 42, it is within the scope of the present disclosure to utilize two different inner solid rods to accommodate a specific application.
Outer tubular rod 44 is attached at one end to one of the bushing assemblies 40 and is attached at its opposite end to the other bushing assembly 40. Outer tubular rod 44 extends through both mounting brackets 34 such that the center section of the sway bar assembly 20 is supported by each mounting bracket 34. Thus, as illustrated in
Referring now to
Outer member 50 includes a cylindrical housing 60 and an attachment cylinder 62 extending radially outward from cylindrical housing 60. Inner member 52 extends through cylindrical housing 60 and it defines two holes 64 which are used to attach sway bar assembly 20 to axle assembly 14. Elastomeric member 58 is disposed between inner member 52 and cylindrical housing 60 of outer member 50. Inner solid rod 42 is attached to attachment cylinder 62 of the outer member 50 by welding or by other means known in the art. As illustrated in
Outer tubular rod 44 is designed to be the primary torsional member. During typical loading conditions, the stresses in outer tubular rod 44 will be significantly higher than the stresses in inner solid rod 42. This will ensure that the backup feature, inner solid rod 42, will remain intact should there be a failure of the primary member, outer tubular rod 44. By having outer tubular rod 44 being designed as the primary torsional member, any failure of outer tubular rod 44 can be detected through routine inspection. Should outer tubular rod 44 fail, sway bar assembly 20 will remain intact due to inner solid rod 42 being held by mounting bracket 34 and extending to bushing assembly 40.
As illustrated, the welding of inner solid rod 42 to bushing assembly 40 and the welding of outer tubular rod 44 to bushing assembly 40 are staggered in the axial direction. The two welds can be in the same plane at the same axial position but the staggering of the two welds allows the weld between inner solid rod 42 and bushing assembly 40 to be supported by outer tubular rod 44 which is press fit over attachment cylinder 62 and inner solid rod 42.
The foregoing description of the embodiments has been provided for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention. Individual elements or features of a particular embodiment are generally not limited to that particular embodiment, but, where applicable, are interchangeable and can be used in a selected embodiment, even if not specifically shown or described. The same may also be varied in many ways. Such variations are not to be regarded as a departure from the invention, and all such modifications are intended to be included within the scope of the invention.
