Abstract:
A suspension system is provided which includes an arm having a zero clearance axle connection. In a described embodiment, a method is provided for manufacturing the suspension system, which method includes the steps of welding an axle connector to an axle, without first pressing the axle connector onto an end of the axle, and without using a clamp to hold the axle connector in contact with the axle, and welding the axle connector to a pivot arm.

Description:
BACKGROUND 
     The present invention relates generally to vehicle suspension systems and, in an embodiment described herein, more particularly provides a suspension system including an arm having a zero clearance axle connection. 
     Many systems and methods have been devised in the past for making an axle attachment in a vehicle suspension system. However, the ongoing efforts to reduce suspension system weight, reduce manufacturing costs, reduce manufacturing inventory and increase manufacturing speed have highlighted the shortcomings of these past suspension systems. 
     In one past suspension system, an axle connector is made up of multiple pieces. The multiple pieces are then assembled and clamped to an axle using a separate clamp. The multiple pieces are then welded to the axle. 
     Note that, in this suspension system, the multiple axle connector pieces must be inventoried, the multiple pieces must be assembled and a clamp must be used to clamp the axle connector to the axle. These extra steps, inventory and manufacturing equipment could be eliminated, thereby reducing manufacturing costs and time. 
     In another past suspension system, and axle connector is pressed onto an end of an axle. A special press must be used in the manufacturing process in order to accommodate the length of the axle. Furthermore, the axle connector and the axle must be machined to close tolerances, so that a precise interference fit is achieved between the parts. 
     Note that, in this suspension system, special manufacturing equipment must be used, and increased costs and time are associated with the close tolerance machining required on the axle and axle connector. This special equipment and increased cost and time could be eliminated, thereby increasing manufacturing economy and speed. 
     SUMMARY 
     In carrying out the principles of the present invention, in accordance with an embodiment thereof, a suspension system is provided which has a reduced number of steps in its manufacture, has a reduced weight, has improved ease of manufacture, and which provides increased strength in an axle to pivot arm connection. 
     In one aspect of the invention, a method of manufacturing a vehicle suspension system is provided. The method includes the steps of welding an axle connector to an axle, without first pressing the axle connector onto an end of the axle, and without using a clamp to hold the axle connector in contact with the axle, and welding the axle connector to a pivot arm. 
     In another aspect of the invention, another method of manufacturing a vehicle suspension system is provided. In the method, an axle connector is connected to an axle by elastically deforming the axle connector. The axle connector extends less than completely about the axle when the axle connector is attached to the axle. 
     The above methods provide many benefits, such as, no clearance existing between the axle connector and the axle, no need for clamps to hold the axle connector in contact with the axle, and no need to press the axle connector over an end of the axle. 
     These and other features, advantages, benefits and objects of the present invention will become apparent to one of ordinary skill in the art upon careful consideration of the detailed description of a representative embodiment of the invention hereinbelow and the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a side elevational view of a suspension system embodying principles of the present invention; 
     FIG. 2 is a perspective view of a pivot arm assembly of the suspension system of FIG. 1; and 
     FIG. 3 is a side elevational view of the pivot arm assembly. 
    
    
     DETAILED DESCRIPTION 
     Representatively illustrated in FIG. 1 is a vehicle suspension system which embodies principles of the present invention. In the following description of the suspension system  10  and other apparatus and methods described herein, directional terms, such as “above”, “below”, “upper”, “lower”, etc., are used only for convenience in referring to the accompanying drawings. Additionally, it is to be understood that the various embodiments of the present invention described herein may be utilized in various orientations, such as inclined, inverted, horizontal, vertical, etc., and in various configurations, without departing from the principles of the present invention. 
     Various typical components of the suspension system  10  have not been illustrated in FIG.  1 . For example, wheels, tires, brake components, etc. have been eliminated from the view shown in FIG. 1, for increased clarity of description and illustration. 
     The suspension system  10  includes a hanger bracket  12  and an air spring  14  for supporting a vehicle frame  16  above the suspension system  10 . A pivot arm assembly  18  is pivotably attached to the hanger  12  by means of a bushing  20 . A shock absorber  22  dampens movements of the pivot arm assembly  18 . 
     The pivot arm assembly  18  is attached at its rearward end to an axle  24 . The axle  24  extends laterally with respect to the frame  16 . In typical fashion, a set of the hanger  12 , air spring  14 , pivot arm assembly  18  and shock absorber  22  are positioned at each opposite end of the axle  24 . Note that, although the axle  24  is depicted in FIG. 1 as being tubular and having a cylindrical cross-section, any axle configuration may be used, without departing from the principles of the present invention. 
     Referring additionally now to FIG. 2, a perspective view of the pivot arm assembly  18  is representatively illustrated. In this view it may be clearly seen that the pivot arm assembly  18  is made up of a bushing tube  26 , a pivot arm  28 , a rear support plate  34  and an axle connector member  36 . The pivot arm  28  includes an upper folded-over portion  30  forming a top and sides of the pivot arm, and a lower portion  32  connecting the sides of the pivot arm. The rear support plate  34  closes off the rear of the pivot arm  28  and provides additional support for attachment of the air spring  14 . 
     The axle connector  36  is uniquely configured and is an important aspect of a method of manufacturing the suspension system  10 . As may be better viewed in FIG. 3, which shows an enlarged side view of the pivot arm assembly  18 , the axle connector  36  is configured so that it extends more than halfway about the axle  24 , without completely encircling the axle. As representatively depicted in FIG. 3, one end of the axle connector  36  extends an angular distance A below horizontal, with respect to the other end of the axle connector. Preferably, the angle A is about 9°, but other angles maybe used in keeping with the principles of the invention. 
     In the method of manufacturing the suspension system  10 , the axle connector  36  is attached to the axle  24  by elastically deforming the axle connector, so that it fits over the outer diameter of the axle. The axle connector  36  then springs back and grips onto the outer diameter of the axle. Thus, when the axle connector  36  is formed, it has an inner radius Rc which is less than an outer radius Ra of the axle  24 . The axle connector  36  is elastically spread, so that its ends  40  fit over the outer diameter of the axle  24  (which also causes its radius Rc to become greater than the axle radius Ra), and then the axle connector is allowed to spring back onto the outer diameter of the axle. 
     This method of attaching the axle connector  36  to the axle  24  provides many benefits. For example, no separate clamps are required to hold the axle connector  36  in contact with the axle  24  while the axle connector is welded to the axle. No special press is required to accommodate the length of the axle  24 , since the axle connector  36  is not pressed over an end of the axle. No close tolerance machining is needed for the axle connector  36  radius Rc or the axle  24  radius Ra, since the elastic grip of the axle connector onto the axle will compensate for a relatively wide range of the radii Rc and Ra. There exists no clearance between the axle connector  36  and the axle  24  at the time the axle connector is welded to the axle, thereby reducing the possibility of stress risers and increasing the strength of the weld. The axle connector  36  is a single member, thereby reducing the number of components which must be inventoried and assembled. The attachment of the axle connector  36  to the axle  24  is a straightforward and quick operation, thereby reducing manufacturing time. Prior to welding, the axle connector  36  may be relatively easily repositioned on the axle  24  for alignment purposes, etc. The axle connector  36  does not extend completely about the axle  24 , thereby permitting it to be attached to the axle from a lateral direction, rather than from an end of the axle, although it could be installed over an end of the axle in keeping with the principles of the invention. 
     After the axle connector  36  is attached to the axle  24 , it may be welded to the axle, and then the axle connector may be welded to the remainder of the pivot arm assembly  18 . Alternatively, the axle connector  36  may be welded to the pivot arm assembly  18  prior to being welded to the axle  24 . Of course, if appropriately configured, the axle connector  36  could also be welded to the pivot arm assembly  18  prior to being attached to the axle  24 . 
     As representatively illustrated herein, the axle connector  36  extends greater than 180° about the cylindrical outer diameter of the axle  24 . However, it will be readily appreciated that, if the axle  24  has another shape, such as rectangular, etc., then the axle connector  36  may also be differently shaped so that it extends greater than halfway about the axle. 
     Note that the axle connector  36  has been described herein as being used to connect a pivot arm  28  to an axle  24 , but other uses may be made of the principles of the present invention. For example, a similar axle connector could be used to attach other components, such as air springs, shocks, spring beams, etc., to an axle. 
     Of course, a person skilled in the art would, upon a careful consideration of the above description of representative embodiments of the invention, readily appreciate that many modifications, additions, substitutions, deletions, and other changes may be made to these specific embodiments, and such changes are contemplated by the principles of the present invention. Accordingly, the foregoing detailed description is to be clearly understood as being given by way of illustration and example only, the spirit and scope of the present invention being limited solely by the appended claims.