Abstract:
A wheel assembly includes: (a) a hub adapted to be mounted for rotation about an axis and defining a housing for enclosing a gear set, the hub having a generally cylindrical outer surface; (b) a ring surrounding the outer surface of the hub; and (c) a generally cylindrical rim surrounding at least a portion of the hub, the rim adapted to carry a tire and having a radially inwardly extending mounting flange. The mounting flange is fastened to the ring.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit of Provisional Application No. 60/981,792 filed Oct. 22, 2007. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    This invention relates generally to off-highway vehicles and other heavy vehicles and more particularly to means for mounting the wheels of such vehicles. 
         [0003]    Many large vehicles, especially off-highway vehicles such as dump trucks and other wheeled mining equipment, use a hub containing a geared final drive or transmission. One or more wheels (also called “rims”) are mounted to this hub. For maximum torque capability and durability, it is desirable to make the transmission components as large as possible while still fitting into the hub. In the prior art, the rims have been mounted so that it is possible to install and remove them conveniently. Unfortunately, this design encroaches on the space available for the transmission components and limits their size. 
       BRIEF SUMMARY OF THE INVENTION 
       [0004]    These and other shortcomings of the prior art are addressed by the present invention, which provides several configurations for mounting tire-carrying rims to a wheel hub. 
         [0005]    According to one aspect of the invention, a wheel assembly includes: (a) a hub adapted to be mounted for rotation about an axis and defining a housing for enclosing a gear set, the hub having a generally cylindrical outer surface; (b) a ring surrounding the outer surface of the hub; and (c) a generally cylindrical rim surrounding at least a portion of the hub, the rim adapted to carry a tire and having a radially inwardly extending mounting flange. The mounting flange is fastened to the ring. By “surrounding,” it is meant extending around, e.g., the ring extends around the outer surface of the hub. 
         [0006]    According to another aspect of the invention, a wheel assembly includes: (a) a hub adapted to be mounted for rotation about an axis, the hub defining a housing for enclosing a gear set and having an inboard end and an outboard end carrying respective inboard and outboard flanges, where at least the outboard flange is segmented; and (b) a generally cylindrical first rim surrounding at least a portion of the hub, the first rim being adapted to carry a tire and having a radially inwardly extending mounting flange. The mounting flange of the first rim is segmented in a complementary relationship to the outboard flange and is fastened to the inboard flange. 
         [0007]    According to another aspect of the invention, a wheel assembly includes: (a) a hub adapted to be mounted for rotation about an axis and defining a housing for enclosing a gear set, the hub having a generally cylindrical outer surface; and (b) a generally cylindrical first rim surrounding the hub and at least a portion of the hub, the first rim being adapted to carry a tire and having a first mounting flange extending axially therefrom. The first rim is fastened to the hub with at least one fastener extending through the first mounting flange and oriented in a generally radial direction. 
         [0008]    According to another aspect of the invention, a wheel assembly includes: (a) a hub adapted to be mounted for rotation about an axis, the hub having a generally cylindrical outer surface; (b) a hollow annular transmission housing carried by and extending axially away from the hub, the transmission housing including: (i) an inboard section having a first outside diameter; (ii) an outboard section having a second outside diameter substantially greater than the first diameter; and (iii) a transition section interconnecting the inboard and outboard sections; (c) an annular adapter ring fastened to the hub and the transmission housing by a first mechanical connection; and (d) a generally cylindrical rim surrounding the transmission housing and at least a portion of the hub, the rim being adapted to carry a tire and having a radially inwardly extending mounting flange which is fastened to the adapter ring by a second mechanical connection. An annular space is defined between the rim and the transmission housing such that the mechanical connections are physically accessible from an outboard end of the transmission housing. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]    The invention may be best understood by reference to the following description taken in conjunction with the accompanying drawing figures in which: 
           [0010]      FIG. 1  is a schematic cross-sectional view of a prior art wheel assembly; 
           [0011]      FIG. 2  is an enlarged view of a portion of  FIG. 1 ; 
           [0012]      FIG. 3  is a schematic cross-sectional view of a wheel assembly, showing a configuration for mounting a rim thereto according to an aspect of the present invention; 
           [0013]      FIG. 4  is a schematic cross-sectional view of an alternative wheel assembly, showing a configuration for mounting a rim thereto according to another aspect of the present invention; 
           [0014]      FIG. 5  is a schematic, exploded perspective view of a wheel assembly, showing a configuration for mounting a rim to a hub according to another aspect of the present invention; 
           [0015]      FIG. 6  is a schematic perspective view of a hub shown in  FIG. 5 ; 
           [0016]      FIG. 7  is a schematic perspective view of a rim shown in  FIG. 5 ; 
           [0017]      FIG. 8  is an end view of the rim shown in  FIG. 7 ; 
           [0018]      FIG. 9  is a schematic, exploded perspective view of a wheel assembly, showing a configuration for mounting a rim to a hub according to another aspect of the present invention; 
           [0019]      FIG. 10  is a schematic perspective view of a hub shown in  FIG. 9 ; 
           [0020]      FIG. 11  is a schematic side view of the hub shown in  FIG. 9 ; 
           [0021]      FIG. 12  is a schematic perspective view of a rim shown in  FIG. 9 ; 
           [0022]      FIG. 13  is a cross-sectional view of the rim shown in  FIG. 9 ; 
           [0023]      FIG. 14  is a cut-away perspective view of the rim shown in  FIG. 9 ; 
           [0024]      FIG. 15  is a schematic cross-sectional view of a wheel assembly, showing a configuration for mounting a rim thereto according to another aspect of the present invention; and 
           [0025]      FIG. 16  is a schematic cross-sectional view of a wheel assembly, showing a configuration for mounting a rim thereto according to yet another aspect of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0026]    Referring to the drawings wherein identical reference numerals denote the same elements throughout the various views,  FIGS. 1 and 2  depict a prior art wheel assembly  10  of the type used for mining dump trucks and other off-highway vehicles. The wheel assembly  10  is shown in half-section, with the understanding that the components are bodies of revolution about the axis “A”. As used herein, the term “axial” refers generally to a direction parallel to the axis A, and the term “radial” refers generally to a direction perpendicular to the axis A. A frame  12  includes a flange  14  or other means for being mounted to the vehicle (not shown) and extends outwardly from the vehicle. A wheel hub (or simply “hub”)  16  is mounted for rotation on the frame  12  by bearings  18 . A generally cylindrical transmission housing  20  is fastened to the outboard end of the wheel hub. As used herein, the term “generally cylindrical” refers to a shape which is primarily a body of revolution about an axis, which may include one or more tapered sections, protrusions (such as flanges or ridges), negative machined features (such as circumferential grooves or axial splines), holes, non-axisymmetrical features, and the like. A transmission or gear set of a known type, for example a multi-stage planetary gear set is carried within the transmission housing  20  and is operably connected to the hub  16  so as to transmit torque from a source, such as a driveshaft or an electric traction motor, to the hub  16 . For illustrative clarity the gear set is only shown schematically at “G”. It will be understood that the design of the present invention is equally useful for mounting wheels which use varying types of gear sets, or no gear set at all. One or more wheels (also referred to as “rims”) are mounted to the hub  16 . In the illustrated example an outboard rim  22 A and an inboard rim  22 B are shown. Each rim  22  has provisions for mounting a tire and an inwardly-extending mounting flange  24 A and  24 B, respectively. 
         [0027]    As seen most clearly in  FIG. 2 , an adapter ring  26  is bolted to the outer end of the hub  16 , and the outboard rim  22 A is bolted to the adapter ring  26 . This is necessary to provide radial clearance so that the inboard rim  22 B can be installed or removed. Unfortunately, when a mounting surface is provided on the hub  16  for the adapter ring  26 , it limits the outside diameter of the transmission housing  20 , which in turn limits the size of the components of the transmission therein. 
         [0028]      FIG. 3  illustrates a first configuration for mounting a rim to a hub  116 .  FIG. 2  illustrates the outboard rim  22 A, with the understanding that the inboard rim (not shown) would be mounted in conventional fashion as shown in  FIG. 1 . A ring  118  with an array of axially-extending threaded holes  120  is placed around the hub  116 . It is held in place, for example, by an optional press fit between its inner diameter and the outer diameter of the hub  116 . Unlike the prior art hub  16 , the hub  116  maintains its maximum outer diameter all the way out to its outboard end. In this particular example the hub  116  is elongated and defines a space for enclosing a gear set G, such that no separate transmission housing is required. The mounting flange  24 A of the outboard rim  22 A abuts the ring  118 . A generally cylindrical sleeve adapter  122  has an inner flange  124  at its inboard end that is mechanically fastened (e.g., with bolts  126 ) to the ring  118  to clamp the outboard rim  22 A. An outer flange  128  of the sleeve adapter  122  is fastened to the hub  116  and/or an end plate  130  (e.g., with bolts  132 ). In operation, the ring  118  carries radial loads from the outboard rim  22 A. The sleeve adapter  122  transmits torque from the end plate  130  to the outboard rim  22 A, and transmits radial loads to the hub  116 . The sleeve adapter  122  also assists with installation and removal of the outboard rim  22 A. For example, bolts or other tooling inserted through the holes in the outer flange  128  can be used to press the rim/ring pair into place. Additional threaded holes may be provided in the outer flange  128  so that bolts (not shown) can be screwed in to bear against the end plate  130  and jack the sleeve/ring/rim combination out of hub  116 . 
         [0029]      FIG. 4  illustrates a second configuration for mounting a rim to a hub  216  similar to the prior art hub  16 .  FIG. 4  illustrates the outboard rim  22 A, with the understanding that the inboard rim (not shown) would be mounted in conventional fashion as shown in  FIG. 1 . A ring  218  with an array of axially-extending threaded holes  220  is placed around the hub  216 . The ring  218  may be continuous, split, or segmented, and there may be a press fit between the ring  218  and the hub  216  if the ring  218  is continuous. In the illustrated example, the ring  218  is held in place by one or more rows of radially-aligned bolts  222  extending into the hub  216 . The ring  218  may be provided with an anti-rotation feature, such as the illustrated spline  224  which is received in a keyway  226  of the hub  216 . The opposite configuration of spline and keyway could be used as well. Unlike the prior art hub  16 , the hub  216  maintains its maximum outer diameter all the way out to its outboard end. In this particular example the hub  216  is elongated and defines a space for enclosing a gear set G such that no separate transmission housing is required, but a separate transmission housing could be used. The mounting flange  24 A of the outboard rim  22 A abuts the ring  218 , and is fastened thereto (e.g., with bolts). In operation, the ring  218  transmits torque and radial loads between the outboard rim  22 A and the hub  216 . 
         [0030]      FIGS. 5-8  illustrate a third configuration for mounting a rim to a hub  316 , which is similar in construction to the prior art hub  16 . The hub  316  includes an inboard flange  318  and an outboard flange  320 . Unlike the prior art hub  16 , the hub  316  maintains its maximum outer diameter all the way out to its outboard. In this particular example the hub  316  is elongated and defines a space for enclosing a gear set such that no separate transmission housing is required. The inboard rim  322 B includes a mounting flange  324 B which is fastened to the inboard flange  318  (e.g., with bolts) and the outboard rim  322 A includes a mounting flange  324 A which is fastened to the outboard flange  320  (e.g., with bolts). 
         [0031]    At least the outboard flange  320  and the mounting flange  324 B of the inboard rim  322 B are segmented, as illustrated. The inboard flange  318  and the mounting flange  324 A of the outboard rim  322 A do not need to be segmented. The segmentation of the outboard flange  320  and the mounting flange  324 B allows the inboard rim  322 B to slide over the outboard flange  320 , in order to bolt the inboard rim  322 B to the inboard flange  318 . The segmentation of the outboard flange  320  and the inboard mounting flange  324 B is complementary, and could have any number of segments and do not need to be identical to each other. Also, neither the rims nor the mounting flanges need to be identical to each other, as long as the complementary relationship is maintained between outboard flange  320  and the inboard mounting flange  324 B. In operation, torque and radial loads are transferred directly between the hub  316  and the outboard and inboard rims  322 A and  322 B via the inner and outer flanges  318  and  320 . 
         [0032]      FIGS. 9-14  illustrate a fourth configuration for mounting a rim to a hub  416 , which is similar in construction to the prior art hub  16 . The hub  416  includes an inboard flange  418  and an outboard flange  420 . Unlike the prior art hub  16 , the hub  416  maintains its maximum outer diameter all the way out to its outboard end. In this particular example the hub  416  is elongated and defines a space for enclosing a gear set such that no separate transmission housing is required, but a separate transmission housing could be used. The inboard rim  422 B includes a mounting flange  424 B which is fastened to the inboard flange  418  (e.g., with bolts) and the outboard rim  422 A includes a mounting flange  422 A which is fastened to the outboard flange  420  (e.g., with bolts). 
         [0033]    At least the outboard flange  420  and the mounting flange  424 B of the inboard rim  422 B are segmented, as illustrated. The segments on the flanges and rims are also shifted or offset into different axial planes as well as being circumferentially segmented. The inboard flange  418  and the mounting flange  424 A of the outboard rim  422 A do not need to be segmented. However, if they are not segmented/split the assembly will require one or more spacers or adapters to allow proper fastening of the outboard rim  424 A to the outboard flange  420 . The segmentation of the outboard flange  420  and the mounting flange  424 B allows the inboard rim  422 B to slide over the outboard flange  420 , in order to bolt the inboard rim  422 B to the inboard flange  418 . The segmentation is configured such that the inboard rim  422 B can reach the inboard flange  418  by axial displacement and rotation about the hub axis. The number and size of segments in both the rims  422 A,  422 B and the hub flanges  418 ,  420  is such that when combined with the number of planes used for segmentation allows the inboard rim  422 A to move axially with some rim rotation about the hub axis. 
         [0034]    The segmentation of the outboard flange  420  and the inboard mounting flange  424 B could have any number of segments and do not need to be identical to each other. Also, neither the rims nor the mounting flanges need to be identical to each other. In operation, torque and radial loads are transferred directly between the hub  416  and the outboard and inboard rims  422 A and  422 B via the inner and outer flanges  418  and  420 . 
         [0035]      FIG. 15  illustrates a fifth configuration for mounting a rim to a hub  516  similar to the prior art hub  16 .  FIG. 15  shows an outboard rim  522 A and an inboard rim  522 B mounted to the hub  516 . The rims  522 A and  522 B do not have a radially-extending mounting flange. Instead, each rim  522 A and  522 B has an axially-extending mounting flange  524 A and  524 B, respectively. Unlike the prior art hub  16 , the hub  516  maintains its maximum outer diameter all the way out to its outboard end. In this particular example the hub  516  is elongated and defines a space for enclosing a gear set G such that no separate transmission housing is required, but a separate transmission housing could be used. The mounting flanges  524 A and  524 B are fastened directly to the outer peripheral surface of the hub  516  (e.g., with bolts  526 ). In operation, torque and radial loads are transferred directly between the hub  516  and the outboard and inboard rims  522 A and  522 B. 
         [0036]      FIG. 16  illustrates a sixth configuration for mounting a rim to a hub  616 . The configuration is similar to the prior art wheel assembly  10  shown in  FIGS. 1 and 2 . A wheel hub (or simply “hub”)  616  is mounted for rotation on a frame  612  by bearings  618 . A generally cylindrical transmission housing  620  is fastened to the outboard end of the hub  616 , and encloses a gear set G (shown schematically). As with the other configurations described above, the hub  616  could be elongated to define a space for enclosing the gear set G, such that no separate transmission housing would be required It will be understood that the design of the present invention is equally useful for mounting wheels which use varying types of gear sets, or no gear set at all. 
         [0037]    The transmission housing  620  includes an inboard section  630  and an outboard section  632  interconnected by a transition section  634 . The inboard section  630  has a first inner diameter “D 1 ” and the outboard section  632  has a second inner diameter “D 2 ” which is substantially greater than the first inner diameter D 1 . As used herein “substantially greater” means that the second inner diameter D 2  is greater that the first inner diameter D 1  by an amount which is more than attributable to ordinary variations in manufacturing tolerances. In this example both sections are generally cylindrical, but other shapes may be used as well. The increase in size of the outboard section  632  permits the gearbox G to be larger than that of the prior art transmission housing  20  seen in  FIG. 1 , allowing it to handle increased torque loads, while utilizing the same size of rim and tire as in the prior art. 
         [0038]    An adapter ring  626  is fastened to the outer end of the hub  616  by a mechanical connection, for example with bolts  636 . The annular adapter ring  626  is made up of two or more segments so that it can be assembled by bringing the segments in around the transmission housing  620  (i.e., in from a radial direction). A rim  622  (in this case an outboard rim) is fastened to the adapter ring  626  by a mechanical connection, for example with bolts  638 . In the illustrated example only the outboard rim  622  is shown. The rim  622  has provisions for mounting a tire, and has an inwardly-extending mounting flange  624 , which accepts the bolts  638 . An inboard rim (not shown) would be mounted to the hub  616  in conventional fashion as shown in  FIG. 1 . 
         [0039]    The size of the outboard section  632  of the transmission housing  620 , while being increased over the prior art, is limited so that it still permits access from the outboard end of the wheel assembly  610  for tools (such as socket wrenches), used to install or remove the bolts  636  and  638 , or otherwise access the adapter ring  626 . This does not require removing or disassembling the transmission housing  620 . In the illustrated example, the second diameter D 2  is about 7.6 cm (3.0 in.) greater than the first diameter D 1 . In the illustrated example the transition section  634  is generally frustoconical in shape, but any convenient cross-sectional profile may be used to achieve the transition. 
         [0040]    Although bolts have been illustrated herein for connecting various elements together, other threaded fasteners (or other fasteners generally) could also be used. 
         [0041]    The foregoing has described several configurations for mounting a wheel to a hub. While specific embodiments of the present invention have been described, it will be apparent to those skilled in the art that various modifications thereto can be made without departing from the spirit and scope of the invention. Accordingly, the foregoing description of the preferred embodiment of the invention and the best mode for practicing the invention are provided for the purpose of illustration only and not for the purpose of limitation.