Abstract:
The present invention relates generally to portal axle gears. Embodiments of the invention provide for full-floating portal gear axles and an indexed steering arm. The full floating portal axle, for example, displaces vehicular weight from the portal gears onto bearings within the portal axel.

Description:
RELATED APPLICATIONS  
       [0001]     The present application claims the benefit under 35 U.S.C. § 119(e) of U.S. provisional application Ser. No. 60/663,430, filed on Mar. 18, 2005, entitled “Portal Axle Apparatus and Method,” which is incorporated herein by reference in its entirety. 
     
    
     FIELD OF THE INVENTION  
       [0002]     This invention relates to axle design and, more particularly, to novel systems and methods for portal axles.  
       BACKGROUND OF THE INVENTION  
       [0003]     Traditional portal axles have many weaknesses and/or problems with use by the general public. The gears both in the differential and the Portal gear box are hard to buy and expensive due to limited supply. Traditional portal axles are also prone to gear failure.  
         [0004]     For example, in traditional portal axles the vehicle or machine weight is placed directly on the gears within the portal. This weight may damage the gears during operation and lowers the gross vehicle weight allowable for a portal axle. Furthermore, traditional axles do not accommodate horizontal torques. For example, during a turn or if a wheel was subject to horizontal resistance a horizontal torque would be applied to the portal axle. Traditional axles were unable to withstand this torque without damage.  
         [0005]     Thus there is need in the art for more robust portal axles that may withstand horizontal torques and that do not place vehicular loads directly on the gears.  
       SUMMARY OF THE INVENTION  
       [0006]     One embodiment of the present invention provides for a portal gear box housing comprising an upper gear housed within the portal gear box; a lower portal gear housed within the portal gear box and in contact with the upper gear; at least one lower inner bearing mount and at least one lower outer bearing mount; a lower inner bearing mounted at the lower inner bearing mount; and a lower outer bearing mounted at the lower outer bearing mount. In such an embodiment, the output shaft is rotatably coupled within the lower inner bearing and within the lower outer bearing and coupled to the lower portal gear thus fully suspending the output shaft within the portal gear box, and wherein the lower inner bearing and the lower outer bearing alleviate the load on the torque bearing surfaces of the lower portal gear. The upper and lower portal gears may be capable of being loaded within the portal gear box without disassembly. The portal gear box may also comprise the following a spindle mounting plate, an indexed steering arm, and an input yolk coupled with the upper gear. In a specific embodiment the upper gear comprises fewer teeth than the lower portal gear. In another variant the portal gear box housing is a single unit.  
         [0007]     In another embodiment of the present invention, the portal axle may further comprise at least one upper inner bearing mount and at least one upper outer bearing mount; a upper inner bearing mounted at the upper inner bearing mount; and a upper outer bearing mounted at the upper outer bearing mount. The input yoke may be, for example, rotatably coupled within the upper inner bearing and within the upper outer bearing and coupled to the upper gear thus fully suspending the input yoke within the portal gear box, and wherein the upper inner bearing and the upper outer bearing alleviate the load on the torque bearing surfaces of the upper gear.  
         [0008]     In another embodiment of the present invention, a portal axle comprises a portal gear box housing with a lower inner bearing mount and a lower outer bearing mount; an output shaft; an input yolk; an upper gear coupled with the input yolk; a lower portal gear coupled with the output shaft and in contact with the upper gear; a lower inner bearing mounted within the portal gear box at the lower inner bearing mount; and a lower outer bearing mounted within the portal gear box at the lower outer bearing mount. The output shaft may be rotatably coupled with the lower inner bearing and the lower outer bearing. This portal axle may further comprise a spindle mounting plate encasing the output shaft; a rotor coupled with the spindle mounting plate; and a hub assembly coupled with the rotor. The spindle mounting plate may be within the hub assembly.  
         [0009]     Yet another embodiment of the present invention provides for a vehicle comprising an engine, a drive train and wheels; a portal gear box housing coupled with each wheel of the vehicle, wherein the portal gear boxes in combination support the weight of the vehicle, the portal gearbox comprising: a lower inner bearing mount and a lower outer bearing mount, wherein the portal gear box; an output shaft; an input yolk coupled with the drive train of the vehicle; an upper gear coupled with the input yolk; a lower portal gear coupled with the output shaft and in contact with the upper gear; a lower inner bearing mounted within the portal gear box at the lower inner bearing mount; and a lower outer bearing mounted within the portal gear box at the lower outer bearing mount. The output shaft may be rotatably coupled with the lower inner bearing and the lower outer bearing. The portal vehicle may further comprise a spindle mounting plate encasing the output shaft; a rotor coupled with the spindle mounting plate; and a hub assembly coupled with the rotor. The spindle mounting plate may be housed within the hub assembly. 
     
    
     BRIEF DESCRIPTION OF THE FIGS.  
       [0010]      FIG. 1  is an exploded, top, partial cross sectional view of a portal axle assembly according to one embodiment of the present invention.  
         [0011]      FIG. 2  is an exploded, top, partial cross sectional view of an alternative portal axle assembly according to another \ embodiment of the present invention.  
         [0012]      FIG. 3  is a top cross sectional view of an alternative embodiment of a portal axle housing in accordance with the present invention according to one embodiment of the present invention.  
         [0013]      FIG. 4  is a partial, cutaway, perspective view of the portal axle assembly of  FIG. 1  according to one embodiment of the present invention.  
         [0014]      FIG. 5  is a top, partial cutaway, assembly view of the portal axle assembly of  FIG. 1  according to one embodiment of the present invention.  
         [0015]      FIG. 6  is a side view of the portal axle assembly of  FIG. 5  according to one embodiment of the present invention.  
         [0016]      FIG. 7  is a side view of one embodiment of a wheel hub plate according to one embodiment of the present invention.  
         [0017]      FIG. 8  is a side, cross-sectional view of the wheel hub plate of  FIG. 7  according to one embodiment of the present invention.  
         [0018]      FIG. 9  is a side view of one embodiment of a lower portal gear according to one embodiment of the present invention.  
         [0019]      FIG. 10  is an opposite view of the portal gear of  FIG. 9  according to one embodiment of the present invention.  
         [0020]      FIG. 11  is a top view of the portal gear of  FIG. 9  according to one embodiment of the present invention.  
         [0021]      FIG. 12  is a perspective view of one embodiment of a portal hub adapter according to one embodiment of the present invention.  
         [0022]      FIG. 13  is a side, cross-sectional view of the portal hub adapter of  FIG. 12  according to one embodiment of the present invention.  
         [0023]      FIG. 14  is a side view of the portal hub adapter of  FIG. 12  according to one embodiment of the present invention.  
         [0024]      FIG. 15  is an exploded view of a front gear case assembly of one embodiment of the present invention.  
         [0025]      FIG. 16  is an indexed steering arm according to another embodiment of the present invention. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0026]     It will be readily understood that the components of the present invention, as generally described and illustrated in the drawings herein, could be arranged and designed in a wide variety of different configurations. Thus, the following more detailed description of the embodiments of the system and method of the present invention, as represented in the drawings, is not intended to limit the scope of the invention, but is merely representative of various embodiments of the invention. The illustrative embodiments of the invention will be best understood by reference to the drawings, wherein like parts are designated by like numerals throughout.  
         [0027]     A portal axle  10  may be attached, for example, to a rotating wheel of a vehicle and may be configured as a steering or non steering portal axle assembly. For example, vehicles require the capability to steer or turn in different directions may be located, for example, on the front or rear of the vehicle or both as required. In addition, the portal axle  10  may be operated as a drive axle or a free wheeling axle. For example, a portal axle  10  may be supplied with power via a vehicle drive train or through an input yoke or shaft, or it may simply roll freely while disconnected to the drive train.  
         [0028]     As shown in  FIG. 1 , one embodiment of the present invention shows a portal gear box  21  that may be constructed of cast iron, stainless steel, aluminum, steel or any other material capable of supporting the rigors of a drive train assembly. The portal gear box  21  may house a lower inner bearing  2 , a lower outer bearing  1 , and a lower portal gear  23 . Attached to the portal gear box  21  is the spindle/mounting plate  29 . Coupled with the lower portal gear  23  is an output shaft  25 . The output shaft  25  may be coupled, for example, with the lower portal gear  23  via, for example, splines on the shaft. A lower inner bearing mount  22  may be cast into the rear or inner portion of the portal gear box  21 . A lower inner bearing mount  22  may be configured to accept the lower inner bearing  2 . A lower inner bearing mount  22  may be configured to accept a sealed cartridge bearing in which the bearing fits within the mount with a snug or pressed fit. Alternatively, the lower inner bearing mount  22  may be configured as a bearing race for accepting a traditional roller bearing cartridge in which the bearing rolls within the bearing race in the lower inner bearing mount  22 .  
         [0029]     A lower inner bearing  2 , for example, can be seated within the lower inner bearing mount  22 . An inner lower bearing  2  rotatably connects the portal gear box  21  to the lower portal gear  18 . An inner lower bearing  14  may also rotatably connect a portal gear box  21  to a modified portal gear  36 . The lower inner gear bearing  2  and the lower outer gear bearing  1 , for example, may be a sealed cartridge bearing, a cartridge bearing, or a traditional roller style wheel type bearing. An inner lower portal gear bearing  14  may also be substituted for another type of device that allows the output shaft  25  and gear  23  to be rotatably connected within the portal gear box  21 .  
         [0030]     The spindle/mounting plate  29  may include an outer lower bearing mount  30 . When the spindle/mounting plate  29  is coupled with the portal gear box  21  the outer lower bearing is securely mounted with in the outer lower bearing mount  30 . As discussed in conjunction with the inner lower bearing mount  22  there are a number of ways to mount the outer lower bearing  1  within the outer bearing mount  30 . From within the portal gear box  21 , the output shaft  25  is coupled with the lower portal gear  23  and extends through the spindle mounting plate  29  and is coupled with the hub assembly  31 ,  32 ,  34 .  
         [0031]      FIG. 1  shows a hub adapter  17  that may be seated, for example, within an inner lower portal gear bearing  17  and connects an inner lower portal gear bearing  14  to a lower portal gear  18 . The surface of a hub adapter  17  may be machined to accept a variety of inner lower portal gear bearings  14  including but not limited to cartridge bearings or traditional roller bearings. A hub adapter  17  may be pressed, welded or otherwise attached within the inner surface of a lower portal gear  18 . Alternatively, a hub adapter may be machined as part of the lower portal gear as shown in item  23  of  FIG. 2 . A hub adapter  17  may be made of titanium, steel including high strength or hardened steel or any other material capable of withstanding the rigors of a vehicle drive train.  
         [0032]     A lower portal gear  18  transfers the power from the vehicle drive train via the upper portal gear to the output shaft  25 . A lower portal gear  18  may have any manner of teeth or drive configuration compatible with a vehicle drive train. A lower portal gear  18  may be constructed of any manner of titanium, steel or high strength steel or any other material capable of withstanding the rigors of a vehicle drive train. The lower portal gear  18 , for example, may be machined to accept a variety of outer lower portal gear bearings  1  or other rotating mechanism including but not limited to sealed cartridge bearings, cartridge bearings or traditional roller style bearings. A lower portal gear  18  may have splines or any other  10  torque transferring mechanism capable of transferring torque from the gears to the output shaft  25 .  
         [0033]     An outer lower portal gear bearing  1  is seated within the lower outer bearing mount  30  and rotatably connects the lower outer bearing mount  30  to the lower portal gear  18 . The outer lower portal gear bearing  1  may be a sealed cartridge bearing, a cartridge bearing or a traditional roller style wheel bearing. The outer lower portal gear bearing  1  may also be substituted for another type of device that allows an output shaft  25  to be rotatably connected with respect to a spindle/mounting plate  29 .  
         [0034]     A spindle/mounting plate  29  may be attached to the outside of a portal gear box  21 . A spindle/mounting plate  29  may be made constructed of steel, cast iron, aluminum or any other material capable of withstanding the rigors of a drive train application. A spindle/mounting plate  29  may have a lower outer bearing mount  30  machined, cast or otherwise formed into the surface facing the inside of the portal gear box  21  to aid in rotatably connecting the spindle/mounting plate  29  to a lower portal gear  18  via an outer lower portal gear bearing  1 . A spindle/mounting plate  29  may have an inner surface that is capable of accepting a wheel hub  31 ,  32 ,  34 . The inner surface of the spindle/mounting plate  29  may be machined, cast or otherwise formed into the surface of the spindle/mounting plate  29  facing the outside of the portal gear box  21 . The inner surface forms a surface in which a wheel hub  32  may be seated into a spindle/mounting plate  29 . A  5  spindle/mounting plate  29  may be mounted in a variety of ways to the portal gear box  21  including but not limited to bolts, hinges, welds or any other method of attachment capable of withstanding the rigors of a vehicle drive train.  
         [0035]     An output shaft  25  transfers the torque from a lower portal gear  18  to a wheel hub  32 . An output shaft  25  may utilize splines or any other method of transferring torque from a lower portal gear  18  to a wheel hub  32 . An output shaft  25  may be configured to adapt from a gear having one diameter to a hub having another diameter as shown in  FIG. 1 . Alternatively, an output shaft  25  may be configured for a gear and a hub having the same diameters as shown in  FIG. 2 . An output shaft  25  may have a variety of different spline configurations including uniform splines along the shaft or two or more sets of splines depending on the varying wheel hub  32  and lower portal gear  18  configurations.  
         [0036]     A wheel hub  32  may mount to a spindle/mounting plate  29 . A wheel hub  32  may have any manner of wheel bearing  31  capable of allowing the output shaft  25  and the wheel mounting plate  34  to rotate within the wheel hub  32 . Typically a wheel hub  32  will be of a standard configuration supplied by a variety of automotive manufacturers. A wheel bearing  31  attached to a wheel hub  32  may be a sealed bearing cartridge or other cartridge bearing. Alternatively, a wheel bearing  30  may be a traditional roller style wheel bearing. The wheel hub  32  may be mounted to a spindle/mounting plate  29  in a variety of different configurations. Depending on the type of wheel bearing  30 , a wheel hub  32  maybe pressed into the spindle/mounting plate  29  or may be bolted or otherwise fixed to the spindle/mounting plate  29 . The tire mounting plate  34  may be configured to accept a variety of different bolt patterns corresponding with the wheels that a customer wishes to use on their vehicle.  
         [0037]     Referring to  FIG. 2 , a modified portal gear  36  may be a manufactured with a hub adapter  17  as part of the lower portal gear  29 . A modified portal gear  23  may have splines that are identical to a commonly used wheel hub  32  so that the output shaft  25  may have uniform splines and be of uniform diameter.  
         [0038]     Referring to  FIG. 3 , a portal gear box  21  and spindle/mounting plate  29  may have a variety of different configurations depending on the original design or manufacturer of the portal gear box  21 . For instance in  FIG. 3 , the spindle/mounting plate  29  is shaped to form a larger part of the apparatus  10 . In this embodiment, a portal gear box  21  is reduced in size to accommodate the spindle/mounting plate  29 . Thus the portal axle  10  is capable of being adapted to a variety of different portal gear box  21  and spindle/mounting plate  29  configurations.  
         [0039]     In another embodiment, the input shaft may also be free-floating in that the input shaft is rotatably coupled with at least two bearings, an inner upper bearing and a lower upper bearing that are mounted within the portal gear box. The input shaft is coupled with the upper gear. In such an embodiment, both the upper and lower gears are free-floating and have negligible vehicle weight on the torque bearing surfaces.  
         [0040]     Referring to  FIG. 4 , a lower portal gear in some embodiments may have splines or some other form of drive mechanism on the inside diameter corresponding with an output shaft  25 . Note that these splines are not depicted in  FIG. 4 . Also note that in  FIG. 4  the inner lower portal bearing  14  is not depicted between the lower inner bearing mount  22  and the hub adapter  17 . In addition, the outer lower portal gear bearing  1  is not depicted between the lower portal gear  18  and the lower outer bearing mount  30 .  
         [0041]     Referring to  FIG. 5 , a wheel hub plate is mounted to a portal gear box  21 . The lower portal gear  18  is shown in an assembly drawing without the inner lower portal gear bearing  14  or the outer lower portal gear bearing  1 .  
         [0042]     Referring to  FIG. 6 , a spindle/mounting plate  29  is shown mounted to a partial depiction of a portal gear box  21 .  
         [0043]     Referring to  FIG. 7 , the inside surface of a spindle/mounting plate  29  is shown with the inner surface  40  in which the wheel hub  32  seats. In addition, a lower outer bearing mount  30  is depicted. The spindle/mounting plate  29  depicted in  FIG. 7  is configured to be mounted to a portal gear box  21  with bolts via the bolt holes  42 .  
         [0044]     Referring to  FIG. 8 , a side cross sectional view of a wheel hub plate  28  includes bolt holes  40  for mounting the wheel hub plate  28  to a portal gear box  21 . In addition, a lower outer bearing mount  30  is depicted. An inner surface  40  is shown and is the surface in which the wheel hub  32  may seat.  
         [0045]      FIG. 9  and  10  show two opposing views of a one embodiment of a lower portal gear according to one embodiment of the present invention.  FIG. 11  shows the top view of the lower portal gear.  
         [0046]      FIG. 12  is a perspective view of one embodiment of a portal hub adapter according to one embodiment of the present invention.  FIG. 13  shows this adapter in a cross-sectional view. And,  FIG. 14 , shows a side view of the hub adaptor.  
         [0047]      FIG. 15  presents another embodiment of the present invention. A three dimensional exploded view of a portal axle is shown. A portal gear box housing  21  is shown. Exploded from within the portal gear box housing  21  is the input yoke  28 , upper gear  5 , lower portal gear  23 , lower inner bearing  2 , lower outer bearing  1 , and the output shaft  25 . The lower portal gear  23  is located between the lower inner and outer bearings  1 , 2 . The spindle/mounting plate  29  is mounted with the portal gear box  21 . The output shaft  25  of the portal axle is coupled with a drive plate  27  that drives the hub assembly  9  and the rotor  7 . The drive plate  27  may also include a drive plate cap  20 . A brake caliper  8  is shown mounted to the spindle mounting plate  29  via the caliper mounting boss  26  and placed over the rotor  7 . A variety of seals  14 ,  18 ,  19  and bearings  4 ,  10 ,  16 , are also shown. The input yolk  28  as shown is coupled to the upper gear  5 . The upper gear  5  is in contact with the lower portal gear  23 . In this specific embodiment the upper gear comprises  16  teeth and the lower portal gear  23  comprises  33  teeth. These gears may comprise a variety of other number of teeth. Depending on the specific application the gears may have the same number of teeth; the upper may have more teeth, etc.  
         [0048]     The lower portal gear  23  is coupled with the output shaft  25  between the lower inner and outer bearings  1 ,  2 . These bearings transfer any load from the output shaft to the portal gear box rather than onto the upper and lower portal gears  5 ,  23 . The upper gear  5  as shown in  FIG. 15  is coupled to the input yoke between two bearings  4 ,  16 . Both the upper and lower portal gears  5 ,  23 , for example, may be loaded into a one piece portal gear box without disassembling the one piece gear box.  
         [0049]     In embodiments of this invention the upper and lower gears are free floating within the gear box. Other embodiments of the present invention allow for more than one lower inner bearing  2  and/or more than one lower outer bearing  1 .  
         [0050]     In another embodiment of the present invention, an indexed and mate-fitted steering arm  24  is coupled to the top of the portal gear box as shown in  FIG. 15 . An exemplary steering arm alone is shown in  FIG. 16 . An indexed and mate-fitted steering arm  24  may, for example, allow for multiple steering geometries by changing only the steering arm and re-utilizing the gear box with a new steering arm. The portal gear box, in this embodiment, includes indexes or mated portions that allow for quick removal and replacement of steering arms.  
         [0051]     The portal axel may also be attached, for example, to the center axle of a vehicle by a tapered bearing in place of a traditional ball joint. Such a configuration may, for example, lessen the negative load characteristics that may plague a ball joint in high stress conditions.  
         [0052]     The present invention may be embodied in other specific forms without departing from its spirit or essential characteristics. The described embodiments are to be considered in all respects only as illustrative, and not restrictive. All changes which come within the meaning and range of equivalency of this disclosure are to be embraced within its scope.