Patent Document

BACKGROUND OF INVENTION  
       [0001]     The present invention relates generally to automotive vehicle steering and suspensions systems and, in particular, to a steering damper to drag link assembly attachment.  
         [0002]     Automotive vehicle steering and suspension systems are well known and are used to steer the front wheels as well as support the vehicle while providing a smooth ride. It is also desirable to damp forces exerted on the wheels of a vehicle in order to keep them from being transferred to the body and steering wheel of a vehicle, which, in turn, results in a more comfortable driving experience. In order to minimize the forces transmitted to a steering wheel through the steering linkage, many steering and suspension systems include a steering damper connected between a drag link assembly (also sometimes called a tie rod assembly, depending upon the particular steering linkage configuration) and an axle housing. The steering damper is a shock absorber that reduces undesirable movement—known as bump steer—that otherwise might be transmitted to the steering wheel when one of the front tires encounters a road surface irregularity.  
         [0003]     In order to attach the steering damper to the drag link assembly, some have done so by drilling a tapered hole through a flat pad portion formed on a solid rod of the drag link assembly. The steering damper is then mounted to the rod with a tapered stud in order to form a tapered pin joint. This positively locates the steering damper (both axially and rotationally) in the correct position on the drag link assembly. But this type of attachment requires more forging and machining operations than is desired, and as a result costs more than is desired for this attachment.  
         [0004]     Others, when employing a hollow tube for the rod portion, have swaged a portion of the hollow tube down to a smaller diameter at the location where the steering damper is to be attached. A bracket, with an opening matching the smaller diameter, can then be positively located axially by mounting it on the smaller diameter portion of the tube. For the steering linkage arrangement that employs the hollow tube, this bracket must be able to rotated relative to the tube while the drag link assembly is being installed and adjusted, so it works adequately. This type of attachment, however, does not positively locate the bracket rotationally, and is more applicable to a hollow tube that can be easily swaged rather than a drag link assembly that employs solid rods. Thus, for drag link assemblies that employ a solid tube and/or require positive rotational retention to maintain the proper orientation of the steering damper attachment assembly, this type of attachment is not particularly desirable either.  
       SUMMARY OF INVENTION  
       [0005]     An embodiment of the present invention contemplates a drag link assembly of a vehicle steering linkage. The drag link assembly may include a main drag link socket assembly including a main rod portion, and a clamp including a curvilinear main body and a pair of spaced apart legs extending therefrom, the main body defining a rod receiving bore within which is mounted the main rod portion of the drag link socket assembly, the legs each including a mounting bolt hole adapted to receive a mounting bolt extending through both of the mounting bolt holes, and the legs adapted to be pulled closer together when a nut operatively engages the mounting bolt thereby causing the main body to apply a clamping load to the main rod portion. A weld is located between and secures the main body of the clamp to the main rod portion whereby the clamp is maintained at a predetermined axial location and rotational orientation on the main rod portion.  
         [0006]     An embodiment of the present invention contemplates a steering linkage for use in an automotive vehicle. The steering linkage may include a steering damper including a first end having a drag link attachment joint, a mounting bolt operatively engaging the drag link attachment joint and including a shank extending therefrom, and a drag link assembly. The drag link assembly may have a main drag link socket assembly including a main rod portion; a clamp including a curvilinear main body and a pair of spaced apart legs extending therefrom, the main body defining a rod receiving bore within which is mounted the main rod portion of the drag link socket assembly, the legs each including a mounting bolt hole through which the shank of the mounting bolt extends; and a weld securing the main body of the clamp to the main rod portion whereby the clamp is maintained at a predetermined axial location and rotational orientation on the main rod portion. Also, a nut operatively engages the mounting bolt against a bias of the legs such that the legs are pulled closer together, causing the main body to apply a clamping load to the main rod portion.  
         [0007]     An embodiment of the present invention contemplates a method for attaching a steering damper, having a drag link attachment joint, to a drag link assembly, having a main drag link socket assembly with a main rod portion, in a vehicle, the method comprising the steps of: providing a clamp including a curvilinear main body and a pair of spaced apart legs extending therefrom, the main body defining a rod receiving bore adapted for receiving the main rod portion of the drag link socket assembly, with the legs each including a mounting bolt hole; mounting the main body of the clamp on the main rod portion at a predetermined axial location and rotational orientation; tack welding the main body of the clamp to the to the main rod portion at the predetermined axial location and rotational orientation; engaging a mounting bolt with the drag link attachment joint; extending a shank of the mounting bolt through the mounting bolt holes of the clamp; and engaging a nut on the mounting bolt against a bias of the legs such that the legs are pulled closer together, causing the main body to apply a clamping load to the main rod portion.  
         [0008]     The present invention advantageously provides an improved way to attach a steering damper to a drag link assembly. The present invention is relatively easy to install, providing positive axial and rotational location for the clamp while attaching the steering damper to the drag link assembly. Moreover, the attachment is cost effective since it minimizes forging and machining operations needed to allow for proper installation.  
         [0009]     Another advantage of an embodiment of the present invention is that the clamp can be employed with a rod portion that is solid or tubular.  
     
    
     BRIEF DESCRIPTION OF DRAWINGS  
       [0010]      FIG. 1  is a perspective, partially broken away view of a portion of a vehicle steering linkage in accordance with the present invention.  
         [0011]      FIG. 2  is a side view of a drag link assembly in accordance with the present invention.  
         [0012]      FIG. 3  is a view of the drag link assembly looking in the direction of line  3 - 3  in  FIG. 2 .  
         [0013]      FIG. 4  is a side view of a main drag link socket assembly in accordance with the present invention.  
         [0014]      FIG. 5  is a view of the main drag link socket assembly looking in the direction of line  5 - 5  in  FIG. 4 , but without a ball joint shown.  
         [0015]      FIG. 6  is a view of the main drag link socket assembly looking in the direction of line  6 - 6  in  FIG. 5 .  
         [0016]      FIG. 7  is a side view of a clamp in accordance with the present invention.  
         [0017]      FIG. 8  is a view of the clamp looking in the direction of line  8 - 8  in  FIG. 7 .  
         [0018]      FIG. 9  is a view of the clamp looking in the direction of line  9 - 9  in  FIG. 8 . 
     
    
     DETAILED DESCRIPTION  
       [0019]      FIGS. 1-9  illustrate a portion of a steering linkage, indicated generally at  12 , for a vehicle. The steering linkage  12  includes a drag link assembly  14 , which is comprised of an outer drag link socket assembly  16 , a drag link adjuster  18 , and a main drag link socket assembly  20 . The drag link assembly  14  is also sometimes called a tie rod assembly, depending upon the particular type of steering linkage, so when the term “drag link” is used herein, this also includes a tie rod). The vehicle steering linkage  12  also includes a steering damper  22  that connects at one end to the drag link assembly  14  and at another end to an axle housing, not shown.  
         [0020]     The outer drag link socket assembly  16  includes an outer rod portion  24 , with adjustment threads  26  at an inner end and a first ball joint  28  at an outer end. The first ball joint  28  may connect to a steering knuckle, not shown. The first ball joint  28  and the steering knuckle will not be described in detail herein since they are both preferably conventional. The adjustment threads  26  engage with the drag link adjuster  18 .  
         [0021]     The drag link adjuster  18  includes an adjuster sleeve  30 , an outer adjuster bracket  32 , and an inner adjuster bracket  34 . The adjuster sleeve  30  has a first set of internal threads, not shown, that engage with the adjustment threads  26  on the outer drag link socket assembly  16 , and a second set of internal threads, not shown, that engage with adjustment threads  36  on the main drag link socket assembly  20 . The internal threads engage with their corresponding threads  26 ,  36  so that when the adjuster sleeve  30  is rotated in one direction, the length of the drag link assembly  14  will decrease, and when rotated in the opposite direction, the length of the drag link assembly  14  will increase. The outer adjuster bracket  32  mounts near the outer end of the adjuster sleeve  30  and includes a first bolt and nut assembly  38 , while the inner adjuster bracket  34  mounts over the inner end of the adjuster sleeve  30  and includes a second bolt and nut assembly  40 . When the bolt and nut assemblies  38 ,  40  are tightened on their respective brackets  32 ,  34 , they secure the threads of the adjuster sleeve  30  relative to the adjustment threads  26 ,  36 .  
         [0022]     The main drag link socket assembly  20  includes a main rod portion  42 , with the adjustment threads  36  at an inner end and a second ball joint  44  mounted in a pocket  46  at an outer end. Preferably, the main rod portion  42  is a solid rod. The second ball joint  44  may connect to a steering knuckle, not shown. The second ball joint  44  and steering knuckle will not be described in detail herein since they are both preferably conventional. One will note that the main rod portion  42  of the main drag link socket assembly  20  includes a dogleg portion  48  and also a pad  50  with a hole therethrough for mating with another portion of the vehicle steering linkage  12 . These features, in addition to the orientation of the first ball joint  28  and second ball joint  44  relative to their respective steering knuckles, require the main drag link socket assembly  20  to be oriented in the vehicle in only one particular rotational orientation. Consequently, the main drag link socket assembly  20  will have a particular orientation relative to the steering damper  22 . A clamp  52 , then, will need to have a particular orientation relative to the main rod portion  42  in order for it to line up with the steering damper  22  and secure the two assemblies together.  
         [0023]     The clamp  52  (best seen in  FIGS. 7-9 ) for securing the steering damper  22  to the drag link assembly  14  is preferably formed from stamped sheet metal in order to reduce the cost of fabrication. The clamp  52  includes a main body  54  from which a first leg  56  and an opposed second leg  58  extend. The main body  54  is formed into a cylindrical shape in order to define a rod receiving bore  60 , through which the main rod portion  42  of the main drag link socket assembly  20  is received. The first leg  56  extends outward from the main body  54  and includes a first mounting bolt hole  62 , and the second leg  58  also extends outward from the main body  54  and includes a second mounting bolt hole  68  that is axially aligned with the first mounting bolt hole  62 . A pair of guide flanges  64  preferably extend from each side of the first leg  56  and taper down in height as they extend from adjacent to the main rod portion  42  out toward the end of the first leg  56 . A second pair of guide flanges  66  preferably extend from each side of the second leg  58  and taper down in height as they extend from adjacent to the main rod portion  42  out toward the end of the second leg  58 . The guide flanges  64 ,  66 , then, will not only provide support for the first and second legs  56 ,  58 , respectively, but, during the assembly process, will also act as guides that direct the clamp  52  onto the main rod portion  42  while causing the legs  56 ,  58  to flex the main body  54  outward around the main rod portion  42 .  
         [0024]     As will be discussed in more detail below, the clamp  52  is fixed at an axial location and a rotational orientation relative to the main rod portion  42  in two ways. A spot weld  70  is applied between the clamp  52  and main rod portion  42 , and a clamping force is applied by the main body  54  to the main rod portion  42 . This assures that the clamp  52  is and will remain located and oriented properly to mate with the steering damper  22 .  
         [0025]     The steering damper  22  includes a first telescoping part  72  mounted to a second telescoping part  74 . The first telescoping part  72  is coupled to a drag link attachment joint  76 , at a first end of the steering damper  22 , while the second telescoping part  74  is coupled to an axle attachment joint  78 , at a second end of the steering damper  22 . The axle attachment joint  78  mounts to a bracket, not shown, extending from the axle housing, not shown. The steering damper  22 , mounting bracket, and axle housing are preferably conventional and so will not be discussed in detail herein. The drag link attachment joint  76  is employed to mount the steering damper  22  to the drag link assembly  14 .  
         [0026]     A mounting bolt  80  engages with the drag link attachment joint  76 , at a first end, and engages with the clamp  52 , at a second end. The mounting bolt  80  includes a head  82  for retaining the mounting bolt  80  in the drag link attachment joint  76 . A shank  84  extends from the head  82  and includes a spacer portion  86  and a threaded portion  88 . The spacer portion  86  of the shank  84  has a diameter that is larger than the second mounting bolt hole  68  and a length that will space the steering damper  22  the desired distance from the drag link assembly  14 . The threaded portion  88  of the shank  84  has a diameter that is smaller than the diameter of the first and second mounting bolt holes  62 ,  68 , and a length that is long enough to extend through both legs  56 ,  58  of the clamp  52 . A nut  90  engages the threaded portion  88  outside of the first leg  56 , securing the mounting bolt  80  to the clamp  52 .  
         [0027]     The assembly and adjustment of the drag link assembly  14 , and the attachment of the steering damper  22  thereto, will now be described. For the main drag link socket assembly  20 , the second ball joint  44  is mounted to the pocket  46  of the main rod portion  42 . The clamp  52 —which can be mounted either before or after the second ball joint  44 —is mounted on main rod portion  42  and positively located both axially and rotationally. For example, it may be oriented at an angle A (seen in  FIG. 6 )—with angle A being about thirty one degrees relative to the main rod portion  42 —and located at an axial distance B (as seen in  FIG. 4 )—with distance B being about six hundred forty six millimeters from the center of the pocket  46 . Of course, the actual axial distance B and orientation angle A needed will vary depending upon the particular vehicle and steering and suspension system.  
         [0028]     With the clamp  52  positively located, the small weld  70 , such as spot weld or tack weld, is then applied between the clamp  52  and the main rod portion  42 . Although this spot weld  70  is generally not sufficient to hold the clamp  52  in place relative to the main rod portion  42  during vehicle operation, it is sufficient to hold it during shipping and while the drag link assembly  14  is being installed and adjusted on a vehicle. By applying only the small weld  70 , the cost and time spent on this operation is minimized, yet, after installation and adjustment, the clamp  52  is in the correct location and orientation to attach the steering damper  22 .  
         [0029]     For the outer drag link socket assembly  16 , the first ball joint  28  is mounted on the outer rod portion  24 . The inner and outer adjuster brackets  32 ,  34  are mounted on the adjuster sleeve  30 , then the adjustment threads  26 ,  36  are engaged with the adjuster sleeve  30 —thus forming the drag link assembly  14 .  
         [0030]     The drag link assembly  14  and steering damper  22  are mounted in the particular vehicle. The steering damper  22  is mounted in the vehicle by connecting the axle attachment joint  78  to the bracket extending from the axle housing. The drag link assembly  14  is mounted in the vehicle by mounting the first and second ball joints  28 ,  44  to their respective steering knuckles and coupling it to another portion (not shown) of the steering linkage  12 . The drag link assembly  14  can now be adjusted. To adjust the distance between the ball joints  28 ,  44 , the adjuster sleeve  30  of the drag link adjuster  18  is rotated, one way to lengthen and the other way to shorten the distance. When desired length is obtained, the bolt and nut assemblies  38 ,  40  on the inner and outer adjuster brackets  32 ,  34  are tightened to prevent the adjuster sleeve  30  from rotating. During this adjustment, the main drag link socket assembly  20  can be held in its proper rotational orientation since it does not need to rotate to adjust the length of the drag link assembly  14 . This allows the clamp  52  to also remain in its proper orientation without having to be rotated relative to the main rod portion  42 , thus allowing the spot weld  70  to remain intact.  
         [0031]     The mounting bolt  80  is inserted into the drag link attachment joint  76  on the steering damper  22  and through the mounting bolt holes  62 ,  68  on the clamp  52 . The nut  90  is threaded onto the mounting bolt  80 . As torque is applied to the nut  90 , the first and second legs  56 ,  58  of the clamp  52  are trapped between the spacer portion  86  of the bolt shank  84  and the nut  90 , causing the legs  56 ,  58  to be drawn together. As the legs  56 ,  58  are drawn together, the main body  54  of the clamp  52  will squeeze tightly around the main rod portion  42 , applying a clamping load to the rod  42 . This clamping action—in addition to the small spot weld  70 —will assure that the clamp  52  permanently maintains its proper axial location and rotational orientation on the main rod portion  42  during vehicle operation.  
         [0032]     While certain embodiments of the present invention have been described in detail, those familiar with the art to which this invention relates will recognize various alternative designs and embodiments for practicing the invention as defined by the following claims.

Technology Category: b