Abstract:
A stabilizer bar assembly includes a stabilizer bar having a bushing, a bushing retainer in mechanical compressive engagement with the bushing, and a mounting bracket adapted to connect the stabilizer bar to an automotive vehicle. The bushing retainer can have a uniform outer diameter such that the bushing is compressed uniformly over the entire length of the bushing retainer, or, alternatively, the bushing retainer can have a stepped outer diameter such that the bushing is compressed differently within discreet sections along the length of the bushing retainer. A method of inducing a pre-load onto a bushing that supports a stabilizer bar includes: providing a stabilizer bar, placing a bushing onto the stabilizer bar, placing a bushing retainer, having an first outer diameter onto the bushing, and reducing the outer diameter of the bushing retainer to a second diameter that is smaller than the first diameter.

Description:
BACKGROUND OF INVENTION  
         [0001]    1. Technical Field of the Invention  
           [0002]    The present invention generally relates to a stabilizer bar for an automotive vehicle. More specifically, the present invention relates to the mounting of bushing onto a stabilizer bar that produces a frictional engagement between the bushing and the stabilizer bar.  
           [0003]    2. Description of the Prior Art  
           [0004]    In an automotive vehicle, a stabilizer bar helps to keep the vehicle level, particularly when the vehicle is traveling through a curve. The ends of the stabilizer bar are connected to the right and left wheel assemblies of the vehicle. A pair of brackets, positioned between the ends of the stabilizer bar, secure the stabilizer bar to a structural component of the vehicle. Rubber bushings positioned between the stabilizer bar and the brackets provide limited torsional, axial and radial movement of the stabilizer bar relative to the bracket. The rubber bushings also dampen the movement of the stabilizer bar. Accordingly, the stiffness, or spring rate, of the bushings affects the feel of the suspension of the vehicle.  
           [0005]    To keep the bushings positioned on the stabilizer bar, a stop is usually formed within, or mounted onto, the stabilizer bar. Sometimes the stops are provided as an annular rib, or ribs, extending around the stabilizer bar. This makes the stabilizer bar more difficult to manufacture and adds weight to the stabilizer bar. Alternatively, the bushings can be secured in position on the stabilizer bar by using a chemical bonding agent. This, again, adds cost and complexity to the manufacturing process.  
           [0006]    Because the stiffness of the bushing affects the vehicle dynamics, bushings having different stiffness are used in different vehicles. This requires the warehousing of different bushings to provide the varying stiffness needed for different vehicles. Further, after time the bushings loose some resiliency, thereby causing the feel of the suspension in the vehicle to change. In order to repair this condition, the bushing would typically have to be replaced, at significant cost.  
           [0007]    As seen from the above, there is a need for an improved stabilizer bar assembly which allows the use of a common bushing to achieve varying stiffness and which can be repaired quickly and economically.  
           [0008]    A principle object of this invention is to provide a stabilizer bar assembly that utilizes common components, yet is able to provide varying stiffness for different vehicle applications.  
           [0009]    Another object is to provide a stabilizer bar assembly that can be adjusted to compensate for a loss of resiliency in the bushings.  
           [0010]    It is also an object of this invention to provide a stabilizer bar assembly having bushings which frictionally engage the stabilizer bar to keep the bushings in position on the stabilizer bar, wherein the bushings are compressed onto the stabilizer bar by a bushing retainer such that the stiffness of the bushing can be adjusted by varying the force at which the bushing retainer compresses the bushings.  
         SUMMARY OF THE INVENTION  
         [0011]    The disadvantages of the prior art are overcome by providing a stabilizer bar assembly, in accordance with the present invention, in which the stabilizer bar assembly includes a stabilizer bar having a bushing mounted thereon. The assembly further includes a bushing retainer that is in mechanical compressive engagement with the bushing such that the bushing is in frictional engagement with the stabilizer bar. A mounting bracket is adapted to connect the stabilizer bar to an automotive vehicle.  
           [0012]    In a first aspect of the present invention the bushing retainer has a uniform outer diameter along its entire length such that the bushing is compressed uniformly over the entire length of the bushing retainer.  
           [0013]    In another aspect of the present invention, the bushing retainer has a stepped outer diameter such that the bushing is compressed differently within discreet sections along the length of the bushing retainer.  
           [0014]    Still another aspect of the present invention is a method of inducing a pre-load onto a bushing that supports a stabilizer bar including: providing a stabilizer bar, placing a bushing onto the stabilizer bar, placing a cylindrical bushing retainer, having an first outer diameter onto the bushing, and reducing the outer diameter of the bushing retainer to a second diameter that is smaller than the first diameter.  
           [0015]    The aspects of the present invention provide a stabilizer bar assembly that uses common components, yet can be adjusted for different vehicle applications, and further, allows the bushing assemblies on the stabilizer bar to be repaired after the bushings have lost some of their resiliency.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0016]    [0016]FIG. 1 is a plan view of a stabilizer bar of the present invention;  
         [0017]    [0017]FIG. 2 is an enlarged view of the portion of the stabilizer bar shown in FIG. 1 enclosed by the circle numbered  2 ;  
         [0018]    [0018]FIG. 3 is a partial perspective view of a first preferred embodiment;  
         [0019]    FIGS.  4 - 7  are sectional views of the first preferred embodiment, shown without a mounting bracket;  
         [0020]    FIGS.  8 - 11  are sectional views of FIG. 3 showing various and alternative aspects of the first preferred embodiment;  
         [0021]    [0021]FIG. 12 is a perspective view similar to FIG. 3, wherein the bushing retainer has a stepped profile;  
         [0022]    [0022]FIG. 13 is a sectional view taken generally along line  13 - 13  of FIG. 12 and showing the stepped profile of the bushing retainer;  
         [0023]    [0023]FIG. 14 is a perspective view of a second preferred embodiment of the present invention;  
         [0024]    [0024]FIG. 15 is a sectional view of the second preferred embodiment taken generally along line  15 - 15  of FIG. 14;  
         [0025]    [0025]FIGS. 16 and 17 are sectional views similar to FIG. 15 showing alternative variations of the second preferred embodiment;  
         [0026]    [0026]FIG. 18 is a sectional view taken generally along line  18 - 18  of FIG. 17 and showing the crimping of the bushing retainer and the mounting bracket;  
         [0027]    [0027]FIG. 19 is a perspective view of a third preferred embodiment of the present invention;  
         [0028]    [0028]FIG. 20 is a sectional view taken generally along line  20 - 20  of FIG. 19 and showing how the mounting bracket engages the bushing retainer;  
         [0029]    FIGS.  21 - 23  are sectional views similar to FIG. 20 showing alternative aspects of the third preferred embodiment; and  
         [0030]    FIGS.  24 - 27  are views of two alternative variations of the third preferred embodiment having a stepped bushing retainer profile. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0031]    Referring to FIGS.  1 - 3 , a stabilizer bar assembly for an automotive vehicle is shown generally at  10 . The stabilizer bar assembly  10  includes a stabilizer bar  12  with at least one bushing assembly  13  mounted thereon. The stabilizer bar  12  is generally made from steel, and can be solid or hollow. It is to be understood, that the stabilizer bar  12  can be made from other suitable materials. The bushing assemblies  13  include a bushing retainer  16  that encompasses a bushing  14  and is in mechanical compressive engagement with the bushing  14  such that the bushing  14  is frictionally engaged with the stabilizer bar  12 .  
         [0032]    The bushing  14  is made from an elastomeric material, such as rubber, or some other resilient material. The bushing  14  is generally sleeve shaped having an cylindrical outer surface and a round passage extending therethrough defining an inner diameter. Preferably, the inner diameter of the bushing  14  is slightly smaller than an outer diameter of the stabilizer bar  12 , however it is to be understood that the present invention can be practiced with a bushing  14  having an inner diameter that is equal to or slightly larger than the outer diameter of the stabilizer bar  12 . Preferably, the bushing  14  is held onto the stabilizer bar  12  by friction alone.  
         [0033]    However, an adhesive can also be applied between the inner diameter of the bushing  14  and the stabilizer bar  12  to provide additional retention of the bushing  14  on the stabilizer bar  12 . Once the bushing  14  is properly located on the stabilizer bar  12 , the bushing retainer  16  is positioned about the bushing  14 . Referring to FIG. 4, the bushing retainer  16  is generally sleeve shaped having a cylindrical outer surface defining a first outer diameter  18  and a cylindrical passage extending therethrough defining an inner diameter. The inner diameter of the bushing retainer  16  is large enough to accommodate the bushing  14 .  
         [0034]    Referring to FIGS. 4 &amp; 5, once the bushing retainer  16  is placed around the bushing  14 , the bushing retainer  16  is reduced to a second, smaller outer diameter  22 . As the outer diameter of the bushing retainer  16  is reduced, the bushing retainer  16  compresses the bushing  14 . When the bushing retainer  16  is reduced to the second diameter  22 , the bushing retainer  16  compresses the bushing  14  against the stabilizer bar  12  with enough force to create a frictional engagement between the stabilizer bar  12  and the bushing  14 , which will prevent relative movement of the bushing  14  and the stabilizer bar  12 . Preferably, the bushing retainer  16  is crimped down to the second diameter  22 , however, other known methods can be employed to reduce the diameter of the bushing retainer  16  and induce the necessary compressive force.  
         [0035]    Preferably, the stabilizer bar  12  has a cross-sectional shape having mirrored longitudinal halves, and the bushing  14  and the bushing retainer  16  have cross-sectional shapes corresponding to the cross-sectional shape of the stabilizer bar  12 . As shown in FIG. 5, the bushing retainer  16  is crimped down from a circular shape to a circular shape. However, the shape of the bushing retainer  16  can be other shapes, an example of which is shown in FIG. 6, wherein the bushing retainer  16  and stabilizer bar  12  are hexagonal. Alternatively, the cross-sectional shape of the bushing retainer  16  and the stabilizer bar  12  can be different, as shown in FIG. 7, wherein the bushing retainer  16  is reduced to a hexagonal shape and the stabilizer bar  12  is round.  
         [0036]    Referring again to FIGS.  1 - 3 , a mounting bracket  24  is attached to the bushing retainer  16  to allow the bushing retainer  16  to be mounted to a structural component of the automobile. Preferably, the mounting bracket  24  includes mounting holes  25  that allow the mounting bracket  24  to be attached to the structure of an automobile. With the bushing  14  being made from a resilient material that allows limited movement of the stabilizer bar  12  relative to the bushing retainer  16 , the bushing assembly  13  provides a spring rate and dampening of the torsional, radial, and axial movement of the stabilizer bar  12  relative to the structure of the vehicle.  
         [0037]    [0037]FIG. 3 illustrates a first preferred embodiment where the mounting bracket  24  is a generally flat piece which is contoured to meet a portion of the outer surface of the bushing retainer  16  and is adapted to be attached to a structural component of the vehicle and wherein the mounting bracket  24  is positioned between the bushing retainer  16  and a structure of the vehicle. The mounting bracket  24  can be welded onto the bushing retainer  16 , as shown by the weld points  25  in the sectional views of FIGS. 8 and 9, or alternatively, the mounting bracket  24  can be riveted onto the bushing retainer  16 , as shown by the rivets  27  in the sectional views of FIGS. 10 and 11. The mounting bracket  24  can be attached to the bushing retainer  16  before the bushing retainer  16  is reduced to the second diameter  22  or after the bushing retainer  16  is reduced to the second diameter  22 .  
         [0038]    Referring again to FIGS. 9 and 11, the bushing retainer  16  is reduced to a uniform second diameter  22  along an entire length of the bushing retainer  16 . The bushing  14  is therefore compressed uniformly over the entire length of the bushing retainer  16 . Alternatively, the stabilizer bar assembly  10  can include a stepped bushing retainer  16   a  as shown in FIGS. 12 and 13. In the stepped configuration, after the bushing retainer  16   a  has been reduced to the second diameter  22 , some portions of the bushing retainer  16   a  are then reduced to a third diameter  26  that is smaller than the second diameter  22 . As shown in FIGS. 12 and 13, portions of the bushing retainer  16  adjacent opposite ends of the bushing retainer  16  are reduced to the third diameter  26 . The stepped bushing retainer  16   a  defines sections wherein the compression of the bushing  14  is different.  
         [0039]    As shown in FIGS. 12 and 13, a first section  28  is defined by a central portion of the bushing retainer  16   a  that has been reduced to the second diameter  22 , and a second section  30  is defined by the end portions of the bushing retainer  16   a , adjacent opposite ends of the bushing retainer  16   a  which have been reduced to the third diameter  26 . The portions of the bushing  14  within the first section  28  are not compressed as much as the portions of the bushing  14  within the second section  30 . Therefore, the portions of the bushing  14  within the second section  30  will provide more stiffness and a higher spring rate.  
         [0040]    One advantage of the present invention is that the same stabilizer bar assembly can be used for applications requiring different spring rates within the bushings  14 . The effective spring rate of the bushings  14  will depend on the amount of compression that is exerted by the bushing retainer  16 . The same assembly can have different spring rates by simply modifying the pressure at which the bushing retainers are crimped. If the stabilizer bar assembly  10  is to be put into a vehicle which requires a soft suspension feel, then the bushing retainer  16  can be reduced to a second diameter  22  which compresses the bushing  14  but still provides a soft feel. If the stabilizer bar assembly  10  is to be installed in a vehicle requiring a stiff suspension, then the bushing retainer  16  can be reduced to an even smaller second diameter  22 , thereby compressing the bushing  14  to a greater extent, and providing a stiffer feel to the suspension.  
         [0041]    The present invention will also add uniformity to the manufacturing of the stabilizer bar systems. When standard bushings and mounting brackets are used, manufacturing variances between parts will cause one assembly to perform slightly different than another one. The amount of crimping of the bushing retainers  16  of the present invention can be controlled by pressure, so that each individual system is compressed until the compression pressure of the bushing  14  meets the specification. In this way, even if there are variances in the size of the bushing retainers  16  and bushings  14 , the compression pressure will be the same, thereby providing more consistent stiffness to the stabilizer bar systems  10 .  
         [0042]    Additionally, the stabilizer bar of the present invention will allow the bushings  14  to be repaired. Over time, as the bushings  14  loose some of their resiliency, their spring rate will change, causing the feel of the vehicle to change. In order to modify the spring rate, all that is required is to re-crimp the bushing retainer  16  to the desired compression pressure. This will allow an older vehicle to have the suspension stiffness adjusted or repaired without having to replace any components of the stabilizer bar system.  
         [0043]    A second preferred embodiment of the stabilizer bar assembly is shown in FIG. 14 and designated at reference numeral  110 , wherein a bushing  114  is positioned onto a stabilizer bar  112  and a bushing retainer  116  secures the bushing  114  onto the stabilizer bar  112 . A mounting bracket  124  extends around and over the bushing retainer  116  to capture the bushing retainer  116  between a structure of the vehicle and the mounting bracket  124 . As shown in FIG. 15, the bushing retainer  116  of the second preferred embodiment has a reduced diameter center section  131  and includes flanges  132  extending radially outward at the ends of the bushing retainer  116 . The mounting bracket  124  extends over and around the bushing retainer  116 , is supported on the flanges  132  of the bushing retainer  116 , and is welded thereto.  
         [0044]    Alternatively, the second preferred embodiment can include a mounting bracket  124   a  which is contoured to fit between the flanges  132  of the bushing retainer  116 . Preferably, the mounting bracket  124   a  fits between the flanges  132  and includes radially extending flanges  134  which contour to the profile of the bushing retainer  116  as shown in FIG. 16. The flanges  134  of the contoured mounting bracket  124   a  extend out beyond the flanges  132  of the bushing retainer  116  to facilitate welding  135  of the mounting bracket  124   a  onto the bushing retainer  116 . In a variation of the contoured mounting bracket  124   a , shown in FIGS. 17 and 18, the flanges  134  are provided coterminous with the flanges  132  of the bushing retainer  116 , wherein the flanges  132  and  134  are crimped together, thereby retaining the mounting bracket  24  onto the bushing retainer  116 .  
         [0045]    A third preferred embodiment of the stabilizer bar assembly is shown in FIG. 19 and is designated as reference numeral  210 . The third preferred embodiment includes a stabilizer bar  212  having a bushing  214  secured thereon by a bushing retainer  216 . The bushing retainer  216  of the third preferred embodiment  210  is a cylindrical sleeve and does not include flanges. A mounting bracket  224  similarly does not include flanges and extends over and around the bushing retainer  216  to secure the bushing retainer  216  between the mounting bracket  224  and a structural component of the vehicle.  
         [0046]    The mounting bracket  224  can be secured to the bushing retainer  216  by welding as shown by the weld points  225  in FIGS. 19 and 20, or alternatively, the mounting bracket  224  can be riveted to the bushing retainer  216 , as shown by the rivets  227  in FIG. 21. The mounting bracket  224  can also be crimped to the bushing retainer  216  as shown in FIG. 22, however, in order to keep the bushing retainer  216  from rotating within the mounting bracket  224 , a non-circular shape would be preferred when crimping the mounting bracket  224  onto the bushing retainer  216 , as shown in FIG. 23.  
         [0047]    Similarly to the first preferred embodiment, the bushing retainer  216  has a first outer diameter and an inner diameter which is sized to accommodate the bushing  214 . After the bushing retainer is placed about the bushing  214 , the bushing retainer  216  is reduced to a second, smaller outer diameter  222 , thereby compressing the bushing  214  therein. The mounting bracket  224  can be placed to the bushing retainer  216  before or after the bushing retainer  216  is reduced to the second outer diameter  222 .  
         [0048]    Additionally, the stabilizer bar assembly  210  of the third preferred embodiment can include a stepped bushing retainer  216   a . Either before or after the mounting bracket  224  is mounted onto the bushing retainer  216   a , portions  225  of the bushing retainer  216   a  are further reduced to a third diameter  226 , which is smaller than the second diameter  222 , leaving a portion  227  which is only reduced to the second diameter  222 .  
         [0049]    Referring to FIGS. 24 and 25, the assembly  210  can include a mounting bracket  224   a  having a width such that the mounting bracket  224   a  is only attached to the portion  227  of the bushing retainer  216   a  which is reduced to the second diameter  222 . The mounting bracket  224   a  can be attached to the bushing retainer  216   a  either before of after portions of the bushing retainer  216   a  are reduced to the third diameter  226 . Alternatively, the assembly  210  can include a mounting bracket  224   b  having a width that is substantially equal to the bushing retainer  216   a  and is placed to the bushing retainer  216   a  prior to portions of the bushing retainer  216   a  being reduced to the third diameter  226 . Both the bushing retainer  216   a  and the mounting bracket  224   b  are then reduced together to a stepped profile, as shown in FIGS. 26 and 27.  
         [0050]    The foregoing discussion discloses and describes three preferred embodiments of the invention. One skilled in the art will readily recognize from such discussion, and from the accompanying drawings and claims, that changes and modifications can be made to the invention without departing from the true spirit and fair scope of the invention as defined in the following claims. The invention has been described in an illustrative manner, and it is to be understood that the terminology which has been used is intended to be in the nature of words of description rather than of limitation.