Abstract:
A wheel and final drive assembly for a work machine, such as a mining truck, having a driven rotatable wheel having inboard and outboard rims mounted thereto. The final drive assembly including a first and a second reduction gear assembly. A ring gear adapter having an inboard end, an outboard end, and an inner surface, a plurality of teeth disposed about said inner surface and interacting with a plurality of planetary gears of the first and second gear reduction assemblies and said inboard end of said ring gear adapter removably coupled to said outboard flange of said wheel.

Description:
TECHNICAL FIELD  
         [0001]    This invention relates to a wheel and final drive assembly having a ring gear output for ground-driven work machine, such as an off-highway truck.  
         BACKGROUND  
         [0002]    Large earth working machines, such as large mining trucks, typically have at least one pair of driven wheels that are rotatably mounted on corresponding axles or spindles. Each wheel may be driven through a final drive assembly, which is typically a double reduction planetary gear arrangement. Typical planetary gear arrangements include a sun gear rotatably coupled to an input shaft, a set of planetary gears disposed about the sun gear and held by a carrier, and a ring gear disposed about the planetary set. The double reduction gear arrangements typically have an input to a first reduction sun gear and an output through a second reduction carrier or ring gear. Power transfer from the first reduction planetary set to the second reduction gear set can be through the first carrier to the second sun gear. A final drive adapter is used to transmit the final output to the rotatably mounted wheel. The final drive adapter couples the second reduction gear assembly to the wheel via a second carrier to wheel adapter or a second ring gear to wheel adapter.  
           [0003]    As the size and capacity of large work machines increases, greater amounts of gear reduction are required to move the machines across the ground. Because the final drive must be confined within the wheel and rim, the structural design and geometric configuration of the final drive adapter can impact the amount of gear reduction. Another problem incurred when designing final drive assemblies with greater gear reduction is the ability to perform routine maintenance. It is preferable, although not always possible, to provide a wheel and final drive assembly that permits maintenance and service of the gear reduction portion of the final drive assembly without having to remove the outboard tire and rim.  
           [0004]    In U.S. Pat. No. 6,148,941, a wheel and final drive assembly having a carrier output adapter is described. The output of the reduction gear assembly is maximized by providing a segmented rim mounting flange attached to an inboard surface of the wheel. The segmented rim mounting flange permits access to the mechanical components of the reduction gear assembly without the need to remove the outboard rim. Although this design increased the amount of gear reduction through the final drive, the continued increase in machine size creates a need for a further increase in gear reduction.  
         SUMMARY OF THE INVENTION  
         [0005]    In one aspect of the present invention, a wheel and final drive assembly for a work machine is provided. The wheel includes an inboard rim mounting flange, an outboard mounting flange and an intermediate portion. The final drive assembly includes a first planetary gear reduction assembly and a second planetary gear reduction assembly. The second gear reduction assembly is positioned outboard of the first gear reduction assembly. A substantially cylindrical ring gear adapter includes an inboard end, and outboard end and an inner surface having a plurality of teeth disposed thereabout. The ring gear adapter interacts with the first and second reduction gear assemblies and is removably attached to the outboard end of the wheel.  
           [0006]    In another aspect of the present invention, a work machine having a wheel and final drive assembly is provided. The wheel includes an inboard rim mounting flange, an outboard mounting flange and an intermediate portion. The final drive assembly includes a first planetary gear reduction assembly and a second planetary gear reduction assembly. The second gear reduction assembly is positioned outboard of the first gear reduction assembly. A substantially cylindrical ring gear adapter includes an inboard end, and outboard end and an inner surface having a plurality of teeth disposed thereabout. The ring gear adapter interacts with the first and second reduction gear assemblies and is removably attached to the outboard end of the wheel. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0007]    [0007]FIG. 1 is a side elevational view of mining dump truck with which this invention may be used.  
         [0008]    [0008]FIG. 2 is a cross-sectional view showing a wheel and final drive assembly in accordance with the present invention.  
         [0009]    [0009]FIG. 2 a  is an enlarged section view of FIG. 2, taken along line  2   b , illustrating one embodiment of the present invention.  
         [0010]    [0010]FIG. 2 b  is an enlarged section view of FIG. 2, taken along line  2   b , of another embodiment of the present invention.  
         [0011]    [0011]FIG. 2 c  is an enlarged section view of FIG. 2, taken along line  2   b , of yet another embodiment of the present invention. 
     
    
     DETAILED DESCRIPTION  
       [0012]    [0012]FIG. 1 illustrates an off-highway truck, generally designated as  10 , on which this invention may be used. The truck comprises a frame  12 , a material carrying dump body  14  pivotally mounted to the frame  12 . A operator cab  16  is mounted on the front of the frame  12  above an engine enclosure  18 . The truck  10  is supported on the ground by a pair of front tires  20  (one shown), and a pair of driven rear tires  22  (one shown) support the truck  10  at the rear. As well known in the art, one or more engines (not shown) are housed within the engine enclosure  18 . The engine is used to provide power to the wheel  20  and final drive assembly  21 , via a mechanical or electric drive train.  
         [0013]    Referring now to FIGS. 2 and 2 a , a wheel  20  and final drive assembly  21  is defined about a horizontal central axis  22 . The final drive assembly  21  includes a first  23  and second reduction gear assembly  25 . A substantially cylindrical spindle  24  is defined about the central axis  22 . The spindle  24  is adapted on a first end (inboard end)  26  to attach to a differential housing (not shown) or an electric drive motor housing. The spindle  24  further defines a hole  28  about the central axis  22 , the hole  28  extends from the inboard end  26  to a second end (outboard end)  30 . An input shaft or drive shaft  27  typically extends through the hole  28  to transmit power to the first planetary reduction gear assembly  23 . A pair of bearing mounting surfaces  32  are defined about an outer surface  34  of the spindle  24 .  
         [0014]    In one embodiment of the present invention, a wheel  20  is rotatably mounted on the spindle  24  via a pair of wheel bearings  36 . The wheel  20  defines an inboard end  38 , an outboard end  40  and an outer surface  42 . The inboard end  38  of the wheel  20  includes a radially outwardly extending inboard rim mounting flange  44  defined about the central axis  22 . An inboard rim assembly  46  is attached to the inboard rim mounting flange  44  in a conventional manner using threaded fasteners. The outboard end  40  of the wheel  20  includes a radially outwardly extending outboard mounting flange  48 , also disposed about the central axis  22 . The outboard mounting flange  48  has an inboard surface  50 , an outboard surface  52  and an outside edge  54  that adjoins the inboard and outboard surfaces  50 , 52 . A plurality of threaded holes  56  are disposed in a circular pattern on the inboard surface  50  about the central axis  22 , the threaded holes  56  extend toward the inboard surface  52 . An outboard annular portion  58  is defined about the central axis  22  near the outboard end  30  of the wheel  20 . The outboard annular portion  58  defines an inner surface  59 . An alignment ring  60  is further defined about the outboard end  30  of the wheel  20 . The alignment ring  60  extends axially outward from the outboard surface  52  of the mounting flange  48  and is preferably integral of the rotatable wheel  20 . The first and second reduction gear assemblies  23 , 25  are adapted to fit within the outboard annular portion  58 .  
         [0015]    A ring gear adapter  62  defines a substantially cylindrical member disposed about the central axis  22 . The ring gear adapter  62  has an inboard end  64 , an outboard end  66 , an inner surface  68  and an outer surface  70 . The inboard end  64  of the ring gear adapter  62  includes a radially outwardly extending mounting flange  72  disposed thereabout. The mounting flange  72  includes an inboard surface  74 , an outboard surface  76  and an outside edge  78  disposed therebetween. A plurality of holes  80  are disposed in a circular pattern about the central axis  22  the and extend from the inboard surface  74  of the mounting flange  70  toward the outboard end  66  of the adapter  62 . A plurality of parallel teeth  82  are disposed about the inner surface  66  of the ring gear adapter  62 . The teeth  82  are oriented in an axial direction. The teeth  82  are adapted to be drivingly engaged with a plurality of teeth (not shown) disposed on a set of planetary gears (not shown) that are included in the second reduction gear assembly  25 . The outboard end  66  of the ring gear adapter  62  is adapted to engage an end plate  84 , or cover. The end plate  84  may be attached by bolts (not shown) or any other suitable attachment method.  
         [0016]    An outboard rim mounting ring  86  is defined about the central axis  22 . The outboard rim mounting ring  86  includes a first inboard surface  88 , a second inboard surface  90  and an exterior surface  92 , adjoining the first inboard surface  88  and an outboard surface  94 . An interior edge  96  is defined between the second inboard surface  90  and the outboard surface  94 . A first plurality of through holes  98  are defined in a circular pattern about the central axis  22  on the outboard rim mounting ring  86 . The first plurality of through holes  98  correspond to the holes  56 , 80  in the wheel  20  and ring gear adapter  62  and extend from the outboard surface  94  to the second inboard surface  90 . A bolt  100  is inserted into each of the holes of the first plurality of through holes  98  of the rim mounting ring, through one of a corresponding hole  80  on the ring gear adapter  62  and into of a corresponding one of the holes  56  of the wheel  20 . A second plurality of holes  102  are defined on the outboard rim mounting ring  86  and positioned about the central axis  22 , at a location radially outward from the first plurality of holes  98 . The second plurality of holes  102  correspond to a plurality of holes  104  on the outboard rim  106 . A rim stud  108  is inserted from the first inboard surface  88  of the rim mounting ring  86  into each of the plurality of through holes  98 . Each rim stud  108  is further aligned with, and inserted into, one of the holes  104  of the outboard rim  106 . A nut  110  engages each rim stud  108  to attach the rim  106  to the rim mounting ring  88 .  
         [0017]    [0017]FIG. 2 b  illustrates an alternate embodiment of the present invention. The plurality of threaded holes  56 ′ defined about the outboard mounting flange  48 ′. The threaded holes  56 ′ are disposed in a circular pattern at a predetermined distance (d1) from the central axis  22 ′. A second (outer) plurality of holes  112  are disposed about the outboard mounting flange at a second predetermined distance (d2) from the central axis  22 ′. The second plurality of holes  112  extend from the outboard surface  52  to the inboard surface  50  of the outboard mounting flange  48 ′. The second plurality of holes  112  correspond with the plurality of through holes  98  defined on the rim mounting ring  86 . The rim mounting ring  86  is removably attached to the outboard mounting flange  48 ′ using common bolts and nuts, but may employ any conventional fastening method.  
         [0018]    The inboard end  64  of the ring gear adapter  62 ′ includes a radially inwardly extending mounting flange  114 . The mounting flange  114  includes an inboard surface  116 , an outboard surface  118  and an inside edge  120  therebetween. A plurality of through holes  122  a disposed in a circular pattern about the central axis  22  and extend from the inboard surface  116  of the mounting flange  114  to the outboard surface  118 . The plurality of holes  122  correspond to the plurality of threaded holes  56 ′ in the outboard end  40  of the rotatable wheel  20 ′. A bolt  100  is inserted through each of the plurality of holes  122  of the ring gear adapter  114  and threaded into one of the plurality of threaded holes  56 ′ of the wheel  20 ′.  
         [0019]    Illustrated in FIG. 2 c , another embodiment of the present invention includes a rotatable wheel  20 ″ having the outboard mounting flange  48 ″ on the outboard end  40  of the wheel  20 ″. A plurality of through holes  124  extend from the inboard surface  50 ″ of the outboard mounting flange  48 ″ to the outboard surface  52 ″. The plurality of holes  124  are defined in a circular pattern around the central axis  22  and correspond to a plurality of threaded holes  128  in the ring gear adapter  62 ″.  
         [0020]    The ring gear adapter  62 ″ includes a radially outwardly extending flange  126  disposed about its inboard end  64 . The plurality of threaded holes  128  in the ring gear adapter  62 ″ extend from an inboard surface  130 . A plurality of through holes  132  are disposed about the outwardly extending flange  126  at a radial distance from the central axis  22  that is greater the distance from the central axis  22  of the plurality of threaded holes  128 . Bolts  134  attach the ring gear adapter  62 ″ to the outboard mounting flange  48 ″ of the wheel  20 ″.  
         [0021]    A rim stud  108  is inserted into each of the plurality of through holes  132  to attach the outboard rim  106  to the ring gear adapter  62 ″.  
       INDUSTRIAL APPLICABILITY  
       [0022]    The wheel  20  and final drive assembly  21  described above provides several advantages over constructions previously known in the art. More particularly, because the ring gear adapter  62  is provides an inner surface  68  that is substantially equal or large in diameter to the annular portion  58  of the wheel  20  the diameter of the ring gear is maximized, therefor maximizing the amount of reduction created by the second reduction gear assembly  25 . In addition, the ring gear adapter being removably attached to the wheel  20  and having a removable end plate  84  allows service and maintenance to the reduction gear assemblies  23 , 25  without having to completely disassemble the final drive assembly  21  and outboard rim  106 .  
         [0023]    Although the presently preferred embodiments of this invention have been described, it will be understood that within the purview of the invention various changes may be made within the scope of the claims.