Abstract:
A kingpin assembly for pivotally supporting a steering knuckle of a steering linkage assembly is disclosed herein. The kingpin assembly includes a pin and a bearing mount assembly. The pin includes a shoulder disposed between a first tapered portion and a second tapered portion. The first tapered portion is structured and arranged for load bearing and is in engagement with the steering knuckle. The second tapered portion is in reverse taper configuration relative to the first tapered portion, measured axially along the pin. The bearing mount assembly has a first bearing half and a second bearing half. The first and second bearing halves sandwiches the second tapered portion for retention thereof. Each of the first and second bearing halves is in engagement with the steering knuckle.

Description:
TECHNICAL FIELD 
       [0001]    The present disclosure relates generally to a steering and suspension linkage assembly. More specifically, the present disclosure relates to a kingpin assembly for the steering and suspension linkage assembly. 
       BACKGROUND 
       [0002]    Various heavy duty machines, such as industrial vehicles, generally include a kingpin for supporting a steering knuckle and a wheel spindle assembly of a steering system. In a double arm suspension system configuration, the kingpin may be fixedly attached to the steering knuckle by forming a tapered joint, and is rotatably attached to an upper control arm and a lower control arm by forming a ball joint at each ends. Hence, the kingpin facilitates, a pivotal movement of the steering knuckle about the upper control arm and the lower control arm, when steered. 
         [0003]    Conventionally, the kingpin is fixedly attached to the steering knuckle by forming the tapered joint. The tapered joint facilitates rotation of the steering knuckle, while supporting a multi-directional and complex loads imparted by wheels of the heavy duty machine. In certain situations, such as an operation of the industrial vehicle on uneven, salient or rugged footing, during an impact event on the suspension system, the load imparted on the steering knuckle often reverses. The reverse load acts to pull the kingpin away from its tapered boss, resulting in failure of the kingpin to maintain the tapered joint. This may further lead to kingpin failure to support the multi-directional loads of the wheel. Therefore, the kingpin is required to be applied with high pull-in force to maintain the tapered joint during reverse loaded conditions. The pull-in force to maintain the tapered joint is achieved via threaded studs, in previously known kingpin designs. However, the threaded studs may require very high assembly torque to be assembled with the kingpin, which may create difficulty in assembling the threaded studs. 
         [0004]    United States Patent, U.S. Pat. No. 4,798,394A discloses a tapered kingpin which pivotally attaches a steering knuckle to a front axle of the vehicle. Although, the kingpin maintains a tapered joint within the front axle, the steering knuckle may be subject to failure or shorter life under heavy reverse load conditions. 
       SUMMARY OF THE INVENTION 
       [0005]    Various aspects of the present disclosure are directed to a kingpin assembly for pivotally supporting a steering knuckle of a steering linkage assembly. The kingpin assembly includes a pin and a bearing mount assembly. The pin includes a first tapered portion, a second tapered portion, and a shoulder disposed between the two tapered portions. The first tapered portion is structured and arranged for load bearing and is in engagement with the steering knuckle. The second tapered portion is in a reverse taper configuration relative to the first tapered portion measured axially along the pin. The shoulder is disposed between the first tapered portion and the second tapered portion measured axially along the pin. Further, the bearing mount assembly includes a first bearing half and a second bearing half. The first bearing half and the second bearing half sandwiches the second tapered portion for retention of the second tapered portion. Each of the first bearing half and the second bearing half is in engagement with the steering knuckle. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0006]      FIG. 1  is a perspective view of a steering and suspension linkage assembly, illustrating a steering linkage assembly assembled with a double arm suspension system, in accordance with the concepts of the present disclosure; 
           [0007]      FIG. 2  is a sectional view of the steering linkage assembly of  FIG. 1  with portions removed to illustrate a kingpin assembly therein; and 
           [0008]      FIG. 3  is an exploded view of the kingpin assembly of  FIG. 2 , illustrating the split bearing assembly to retain the kingpin assembly. 
       
    
    
     DETAILED DESCRIPTION 
       [0009]    Referring to  FIG. 1 , there is shown a steering and suspension linkage assembly  100  of a heavy duty machine. The heavy-duty machines may embody a construction machine, a load carrying machine, a forest machine, and the like. The steering and suspension linkage assembly  100  of the heavy duty machine includes a steering linkage assembly  102 , a double arm suspension system  104 , and a kingpin assembly  106 . In a heavy duty machine that employs the double arm suspension system  104 , the steering linkage assembly  102  and the double arm suspension system  104  are attached via the kingpin assembly  106 . 
         [0010]    The steering linkage assembly  102  is provided with a spindle assembly  110 , and a wheel assembly (not shown) may be rotatably attached thereto, as is customary. The steering linkage assembly  102  may include a steering knuckle  108 , the spindle assembly  110 , and a steering arm  112  which, when urged to move by the connected steering linkage (not shown), then the spindle assembly  110  rotates, and redirects the wheel to steer the machine (not shown). 
         [0011]    Referring to  FIG. 2 , the steering knuckle  108  may be cylindrically-shaped having an outer periphery  114 , and a through-hole  116  therein. The kingpin assembly  106  includes an axis X-X, along which the steering knuckle  108  is configured to perform a pivotal movement, coincident with the movement of the steering arm  112  ( FIG. 1 ). 
         [0012]    Referring back to  FIG. 1 , the spindle assembly  110  and the steering arm  112 , are attached to the outer periphery  114  of the steering knuckle  108 . Both the steering arm  112  and the spindle assembly  110  extend radially outwards from the outer periphery  114 . 
         [0013]    The double arm suspension system  104  may include an upper control arm  118 , a lower control arm  120 , and a shock absorber  122  attached to the upper control arm  118 , to counteract an impact event experienced by the wheel (not shown) as is customary. Each of the upper control arm  118  and the lower control arm  120  are connected to a machine frame  124  at one end. At the other end, the upper control arm  118  and lower control arm  120  are axially aligned with the through-hole  116  of the steering knuckle  108 . The upper control arm  118  and the lower control arm  120  are rotatably attached to opposite ends of the steering knuckle  108 , via the kingpin assembly  106 . 
         [0014]    Referring again to  FIG. 2 , the kingpin assembly  106  is rotatably supported by the upper control arm  118  ( FIG. 1 ) and the lower control arm  120  ( FIG. 1 ). The kingpin assembly  106  may include a pin  202 , and a bearing mount assembly  204 . 
         [0015]    The pin  202  extends inside the through-hole  116  of the steering knuckle  108 , while forming a tapered joint with the steering knuckle  108 . The pin  202  includes a first hemispherical end  206  and a second hemispherical end  208 . The first hemispherical end  206  and the second hemispherical end  208  are respectively rotatably connected to the upper control arm  118  and the lower control arm  120 , through ball joints (not shown), for example. The present disclosure contemplates that alternative connection linkages may be used including those which are known to those having ordinary skill in the art. 
         [0016]    The pin  202  includes a first tapered portion  210 , a second tapered portion  212 , and a shoulder  214 . The shoulder  214  of the pin  202  is disposed between the first tapered portion  210  and the second tapered portion  212 . The first tapered portion  210  of the pin  202  is structured and arranged for load bearing and is in engagement with an inner tapered portion  115  of the steering knuckle  108 . The first tapered portion  210  of the pin  202 , while being disposed inside the through-hole  116 , forms a tapered joint with the inner tapered portion  115  of the steering knuckle  108 . The tapered joint enables the pin  202  to support the multi-variant loads exerted by wheels of the heavy duty machine. 
         [0017]    The second tapered portion  212  of the pin  202  is not continuous with the first tapered portion  210 . Instead, the shoulder  214  is disposed between the first tapered portion  210  and the second tapered portion  212 . The second tapered portion  212  is tapered in the opposite direction along the axis X-X compared to the first tapered portion  210 . The second tapered portion  212  may be characterized as a reverse-taper configuration relative to the first tapered portion  210 , as measured along the kingpin axis X-X. The second tapered portion  212  is positioned outside of the through-hole  116  of the steering knuckle  108 , to support the bearing mount assembly  204 . 
         [0018]    The bearing mount assembly  204  will now be described. As best seen in  FIG. 3 , the bearing mount assembly  204  respectively includes a first bearing half  216  and a second bearing half  218  which are bolted together by threaded fasteners  205  ( FIG. 2 ), to sandwich the second tapered portion  212  of the pin  202  between these bearing halves  216 ,  218 . As best seen in  FIG. 2 , each of the first bearing half  216  and the second bearing half  218  are in engagement with the steering knuckle  108 . More particularly, a top surface  219 ,  220  of each of the first bearing half  216  and the second bearing half  218  abuts with a face portion  221  of the steering knuckle  108 . In this manner, the pin  202  may be free to rotate within the bearing mount assembly  204 . However, it is restrained from movement in the direction toward the first hemispherical end  206  of the pin  202 , along the axis X-X. 
         [0019]    Moreover, each of the first and second bearing halves  216 ,  218  include bearing surfaces  222 ,  223  which engage the second tapered portion  212  of the pin  202 . The first and second bearing halves  216 ,  218  also respectively have an edge portion  224 ,  225  which contact the shoulder  214  of the pin  202 . The pin  202  is also restrained relative to the steering knuckle  108  in the direction toward the second hemispherical end  208  of the pin  202  along the axis X-X, since the edge portions  224 ,  225  of the bearing mount assembly  204  engage the shoulder  214  of the pin  202  to prevent significant movement of the pin  202  along the axis X-X relative to the steering knuckle  108  coinciding with normal loading conditions. This use of the bearing mount assembly  204  to engage the shoulder  214  of the pin  202  may help set the degree of engagement between the first tapered portion  210  of the pin  202  and the inner tapered portion  115  of the steering knuckle  108 . As a result, the friction inherent with the rotating first tapered portion  210  of the pin  202  and the steering knuckle  108  can be kept within an acceptable tolerance through the engagement of the shoulder  214  of the pin  202  with the edge portions  224 ,  235  of the bearing mount assembly  204 . 
         [0020]    During assembly, the first bearing half  216  and the second bearing half  218  are bolted together using the fastener  205 . In that scenario, the pin  202  is slightly pulled in a direction toward the second hemispherical end  208  of the pin  202  along the axis X-X. This enables a tighter tapered joint being formed between the pin  202  and the steering knuckle  108 . In this manner, the pin  202  restrained from movement in the direction toward the first hemispherical end  206  of the pin  202  along the axis X-X, during heavy reverse loaded conditions. 
       INDUSTRIAL APPLICABILITY 
       [0021]    In operation, the kingpin assembly  106  is positioned between the upper and lower control arms  118 ,  120  through the first and second hemispherical ends  206 ,  208  of the pin  202 , making ball joint connections with the upper and lower control arms  118 ,  120 . The kingpin assembly  106  transfers the weight of the machine to the wheel(s) through the first tapered portion  210  of the pin  202 , as it interfaces with the first tapered portion  210  of the steering knuckle  108 . 
         [0022]    As the wheel moves over uneven ground, the shock absorber  122  counteracts against the motion of the wheel (not shown). Regardless of the suspension status, the steering may be carried out by the steering arm  112  being rotated, which in turn moves the steering knuckle  108  including the spindle assembly  110 , which is attached to the wheel (not shown). However, during extreme machine operation, which is common for construction equipment operation, the double arm suspension system  104  may experience an impact and the resulting impact will reverse the load as the recoil force of the machine urges the machine upwards. The result is the pin  202  attempting to separate from its interface with the first tapered portion  210  of the steering knuckle  108 , resulting in failure to maintain the tapered joint. However, since the bearing mount assembly  204  is placed at the second tapered portion  212  (reverse tapered to the first tapered portion  210 ) of the pin  202 , and the top surface  220  of the bearing mount assembly  204  is in contact with the face portion  221  of the steering knuckle  108 , the pin  202  is fully retained within the steering knuckle  108 . The result is the pin  202  is retained during reverse loading and the steering is insubstantially affected by reverse loading. The steering knuckle  108  is allowed to freely rotate relative along the axis X-X, regardless of the machine loading events. 
         [0023]    It should be understood that the above description is intended for illustrative purposes only and is not intended to limit the scope of the present disclosure in any way. Thus, those skilled in the art will appreciate that other aspects of the disclosure may be obtained from a study of the drawings, the disclosure, and the appended claim.