AXLE ASSEMBLY

Abstract

An improved axle may comprise three design features that, used individually or in combination, may drastically improve axle performance and decrease the likelihood of axle damage and/or deformation resulting from vehicle weight, jounce load, combined cornering load, and/or curb strike load. These three features are: dual opposed tapered roller bearings, increased shaft diameter at the bearings, and reinforced flange back face.

Claims

1. An axle assembly for a vehicle, comprising: a shaft; a hub comprising a hub flange; and a bearing assembly; wherein: the hub flange comprises a front side and a back side; when viewed from the front side, the hub flange is circular; when viewed from the back side the hub flange is circular; the front side of the hub flange faces away from the center of the vehicle; the back side of the hub flange faces toward the center of the vehicle; the hub flange has a first hole from the front side of the hub flange to the back side of hub flange; the first hole is not located in the center of the hub flange; the first hole is configured to accept a first piece of securing hardware comprising a substantially cylindrical body and a head on one end of the body; the first hole is sized to allow the cylindrical body of the first piece of securing hardware head to pass, but to not allow the head of the securing hardware to pass; and an imaginary circle having a center at the center of the circular hub flange, concentric with the circular shape of the hub flange as viewed from the front side or the back side; and having a radius that is the distance from the center of the circular hub flange to the point on the front side of the head of securing hardware that is nearest to the center of the circle passes through the hub flange.

2. The axle of claim 1, wherein the surface of a segment of the shaft is in mechanical force-transferring contact with an inner surface of the bearing assembly

3. The axle of claim 2, wherein the bearing assembly comprises dual tapered roller bearings.

4. The axle of claim 2, wherein the maximum diameter of the segment of the shaft in contact with the inner surface of the bearing assembly is greater than the minimum diameter of the shaft that is not in contact with the bearing assembly.

5. The axle of claim 4, wherein the diameter along the segment of the shaft in contact with the inner surface of the bearing assembly is uniform.

6. The axle of claim 5, wherein the diameter along the segment of the shaft in contact with the inner surface of the bearing assembly is 2.000 inches.

7. The axle of claim 4, wherein the minimum diameter of the axle segment not in contact with the bearing assembly is 1.510 inches.

8. The axle of claim 44, wherein the length of the segment of the shaft in contact with the bearing assembly is 2.630 inches.

9. The axle of claim 2, wherein the bearing assembly comprises straight roller bearings.

10. The axle of claim 1, wherein the back size of the hub flange is a convex curve from the bearing assembly to the outside edge of the hub flange.

11. The axle of claim 1, wherein the lip on the back side of the first hole is not a planar circle.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0026] FIG. 1 shows a cross-section view of an exemplary semi-float axle.

[0027] FIG. 2 shows a cross-section view of an exemplary semi-float axle undergoing a displacement along the shaft as a result of a force applied to the hub flange.

[0028] FIG. 3 shows a cross-section view of an exemplary semi-float axle that has a permanent shaft bend.

[0029] FIG. 4 shows a cross-section view of an exemplary full-float axle.

[0030] FIG. 5 shows a cross-section view of an exemplary semi-float axle with a graduated shaft diameter.

[0031] FIG. 6a shows a cross-section view of an exemplary improved axle.

[0032] FIG. 6b shows front elevated cross-section view of an exemplary improved axle.

[0033] FIG. 7 shows a cross-section view of an exemplary improved axle, focusing on forces transmitted through the bearing assembly.

[0034] FIG. 8a shows a cross-section view of the hub/flange portion of an exemplary improved axle.

[0035] FIG. 8b shows a side view of the hub end of an exemplary improved axle, without the studs for securing the wheel.

[0036] FIG. 8c shows a side view of the hub end of an exemplary improved axle, with the studs for securing the wheel.

[0037] FIG. 8d shows a rear elevated angle view of the hub end of an exemplary improved axle, without the studs for securing the wheel.

[0038] FIG. 8e shows a rear elevated angle view of the hub end of an exemplary improved axle, with the studs for securing the wheel.

[0039] FIG. 9a shows an elevated-angle exploded view of an exemplary bearing assembly for an improved axle as described herein.

[0040] FIG. 9b shows a cross-section view of an exemplary bearing assembly for an improved axle as described herein.

[0041] FIG. 10a shows an elevated-angle rear exploded view of an improved axle as described herein.

[0042] FIG. 10b shows an elevated-angle rear view of an improved axle as described herein.

[0043] FIG. 10c shows a front elevated-angle partially-exploded view of an improved axle as described herein.

[0044] FIG. 10d shows a rear elevated-angle view of an exemplary improved axle as described herein.

[0045] FIG. 10e shows a front elevated-angle exploded view of an exemplary improved axle as disclosed herein.

[0046] FIG. 10f shows a front close-up elevate angle view of an exemplary improved axle as disclosed herein.

[0047] FIG. 11 shows a cross-section view of the hub/flange portion of an exemplary improved axle as described herein. As shown in FIG. 11, the front of the hub/flange has not been “cupped” or hollowed out.

DETAILED DESCRIPTION OF THE INVENTION

[0048] This application claims priority to U.S. Provisional Application No. 62/991,214 filed on Mar. 18, 2020, titled “Axle Assembly,” and the first inventor of which is Jim McGean. This application is incorporated by reference in its entirety.

[0049] An improved axle for recreational vehicles and/or other vehicles is disclosed.

TABLE OF REFERENCE NUMBERS FROM DRAWINGS

[0050] The following table is for convenience only, and should not be construed to supersede any potentially inconsistent disclosure herein.

TABLE-US-00001 Reference Number Description  100 semi-float axle assembly  110 hub  120 axle shaft  130 axle bearing assembly  140 differential box or gear box  180 reaction point  194 force of vehicle weight and jounce load  196 combined cornering load  198 curb strike load  210 spatial deflection force along axle shaft  215 bend point on axle shall  310 permanent bend in axle shaft  400 full-float axle assembly  410 outer bearing assembly  415 inner bearing assembly  420 spindle  425 rigid axle housing  440 hub  442 wheel-mounting surface  444a-n threaded stud/bolt  450 axle shaft  490 vehicle weight and jounce load  492 combined cornering load  494 curb strike load  500 tapered semi-float axle assembly  510 hub  520 axle shaft  522 segment of axle shaft  523 axle diameter-eduction point  524 segment of axle shaft  525 axle diameter reduction point  526 segment of axle shaft  530 axle bearing  540 differential box or gear box  580 reaction point  594 force of vehicle weight and jounce load  596 combined cornering load  598 curb strike load  600 improved axle assembly  605 axle  610 segment of axle from transition segment to differential box  620 transition segment of axle  622 small diameter end of axle transition segment  624 large diameter end of transition segment  626 bearing-interface axle segment  629 transition from shaft to hub/shaft portion of axle  627 outer surface of bearing-interface axle segment  630 bearing assembly  632 differential-side bearing  633 inner race of differential-side bearing  634 outer race of differential-side bearing  635 rollers in differential-side bearing  636 wheel-side bearing  637 inner race of wheel-side bearing  638 outer race of wheel-side bearing  639 rollers in wheel-side bearing  640 seal  641 bearing housing  650 flange  651 back flange surface  652 wheel-mounting surface  653a-n wheel-mounting bolts/studs  654 outer edge of flange  655 inside surface of flange cup  656 front side of flange  710 load transferred through differential-side bearing  715 load point offset from differential-side bearing  720 load transferred through wheel-side bearing  725 load point offset from wheel-side bearing  740 direct downward force  810a-n stud body  820a-n stud head  822a-n bottom of stud head  823a-n inner side of stud head  824a-n outer side of stud head  828a-n top of stud head  850 mounting plate  852 washer  854 set screw  856 retainer nut  858 snap ring  860 O-ring  862 differential side of axle housing  864 differential 1100 hub/flange without frontside cupping 1110 front side of hub/flange

[0051] An improved axle design is disclosed. The improved axle design combines three design features that, when used together, drastically improve axle performance and decrease the likelihood of axle damage and/or deformation resulting from vehicle weight, jounce load, combined cornering load, and/or curb strike load. These three features are: dual opposed tapered roller bearings with optimized spacing, increased shaft diameter at the bearings, and reinforced flange back face. Although performance is maximized when these three features are used together, use of one or more of these three features may result in performance gains.

[0052] FIG. 6a shows a cross section of an exemplary improved axle. FIG. 6b shows an elevated angle cross-section view of an exemplary improved axle

[0053] The dimensions described in the description herein are exemplary. The axle assembly disclosed herein may be scaled or adjusted without departing from the scope of this disclosure.

[0054] Axle Shaft Diameter

[0055] As shown in FIG. 6a, axle segment 610 may be a shaft made out of steel or any material known in the art for axles and may have a diameter of 1.510 inches. Increasing the diameter of axle segment 610 results in greater strength and rigidity, but also increases weight and cost. Although FIG. 6a shows the axle segment 610 as having a uniform diameter along the entire length of the segment, the axle may have a non-uniform diameter, although non-uniformity of diameter may result in force concentration instead of distribution. Uniform diameter of axle segment 610 promotes ductility and short duration shock absorption to avoid permanent shaft deformation and failure.

[0056] Axle transition segment 620 may have a length of 1.344 inches and a diameter of 1.510 inches at small-end 622, and a diameter at large-end 624 of 2.000 inches. The diameter at small-end 622 diameter may be the same as the diameter of axle segment 610, and the large-end 624 diameter may be the same as the diameter of bearing-interface segment 626. Although axle transition segment 620 is shown in FIG. 6a as having a linear transition, i.e., the diameter increases linearly from small end 622 to large end 624, in some embodiments the transition may have a non-linear transition profile.

[0057] Bearing-interface axle segment 626 is adjacent to and interfaces with bearing assembly 630. Bearing-interface axle segment 626 may have a length of 2.630 inches and a diameter of 2.000 inches. In one embodiment, the length of bearing-interface axle segment 626 may be approximately the length of bearing assembly 630.

[0058] In general, the diameter of bearing-interface axle segment 626 may be equal to the inner diameter of bearing assembly 630, so that outer surface 627 of bearing-interface axle segment 626 interfaces with bearing assembly 630 as shown in FIG. 6a. In general, using a bearing-interface axle segment 626 with a diameter that is larger than the diameter of axle segment 610 (or larger than the minimum diameter of axle segment 610) has several benefits. First, torque forces are transferred to the smaller-diameter segment of axle 605, i.e., to segment 610, and because segment 610 is much longer than segment 626, the torque forces and resulting torque deflection are distributed over a longer segment of axle 605, increasing the ability of axle 605 to dissipate torque deflection without permanent deformation. Second, shifting torque forces protects the bearing assembly 630's moving parts and tight tolerances, which are susceptible to damage that may result from torque deflection in bearing-interface axle segment 626.

[0059] Third, increased diameter of bearing-interface axle segment 626 necessarily requires a complementarily sized bearing assembly 630. Increased diameter of bearing-interface axle segment 626, and complementarily increased diameter of bearing assembly 630, results in increased surface contact between bearing-interface axle segment 626 and inner races 633 and 637 of bearing assembly 630, thereby increasing axle 605's resistance to axial deviation.

[0060] The length and/or diameter profile of axle segment 626 may be adjusted based on characteristics of a particular application, e.g., overall length of the axle, weight of the vehicle, anticipated vehicle use, size dimensions of vehicle and/or components, anticipated moment forces, and/or any other well-known engineering principles relating to the characteristics of the forces likely to be exerted on the axle at or near the bearings.

[0061] Bearing Assembly

[0062] Bearing assembly 630 may be a dual angled tapered bearing comprising wheel-side bearing 636 and differential-side bearing 632. As shown in FIG. 6a, bearing 636 and bearing 632 are positioned and oriented as dual opposed tapered roller bearings. Rollers 639 in wheel-side bearing 636 and rollers 639 in differential-side bearing 632 are angled inward to create a cradle-like cross section upon which outer races 634 and 638 move.

[0063] Several benefits result from a dual-angled-tapered bearing design: increased total bearing radial load capacity, additional support for bearing-interface axle segment 626, and increased rigidity of bearing-interface axle segment 626. The dual-bearing design distributes vehicle weight and road loads over the length of the entire dual-bearing assembly 630, instead of over just the width of one bearing as in a single bearing design.

[0064] As shown in FIG. 7, the separation between differential-side bearing 632 and wheel-side bearing 636, as well as the angle and tapering of rollers 635 in differential-side bearing 632 and of rollers 639 in wheel-side bearing 636, result in the load directions 710 and 720, and load point offsets 715 and 725. As the distance between load point offset 715 for differential-size bearing 632 and load point offset 725 for wheel-side bearing 636 increases, the vehicle weight and road load transferred through bearing assembly 630 to bearing-interface axle segment 626 are distributed along a longer length of axle segment 605, resulting in increased rigidity along the bearing-interface axle segment 626.

[0065] In one embodiment, each of differential-side bearing 632 and wheel-side bearing 636 may have a width of 0.975 inches, and may be separated by 0.263 inches.

[0066] Differential-side bearing 632 and wheel-side bearing 636 may each have a width of approximately 0.8750 inches. In general, increasing the distance between differential-side bearing 632 and wheel-side bearing 636 increases distribution along bear-interface axle segment 626 of forces 715 and 725 transferred through bearings 632 and 636 to bearing-interface axle segment 626, thereby decreasing the probability that axle 605 will bend or deform. Increasing the distance between bearings 632 and 636 also increases the rigidity of bearing-interface axle segment 626, thereby decreasing the tendency of bearing assembly 630 to act as a reaction or pivot point spatial deflection of axle 605.

[0067] Although the distance between bearings 632 and 636 may be adjusted depending on particular design constraints or on a particular application, the maximum distance is subject to several limitations. First, placement of other components, e.g., the brake assembly, limits the distance between bearings 632 and 636. Second, manufacturing, design, and vehicle assembly considerations limit the distance between bearings 632 and 636. Third, because bearing-interface axle segment 626 may not be perfectly straight, increasing the distance between bearings 632 and 636 amplifies the effect of any deviations from perfect straightness in bearing-interface axle segment. If bearings 632 and 636 are too far apart, the effect of imperfections in the straightness of bearing-interface axle segment 626 may exceed acceptable thresholds. Fourth, manufacturing and alignment tolerances on the bearings 632 and 636 individually, as well as on their alignment relative to each other, tighten as the distance between bearings 632 and 636 increases. Tighter tolerance requirements may increase the cost of manufacturing, or may even be impossible to satisfy.

[0068] Although the detailed embodiment described herein includes dual tapered bearings, other bearing designs could be used. For example, ball bearings or straight roller bearings could be used. However, these alternate designs have drawbacks. In a ball bearing design, all vehicle weight and road load are transferred through only one contact point on each ball, thereby placing significant stress on each ball. Also, instead of distributing vehicle weight and road load jounce load along a segment of the axle shaft, in a ball bearing design the vehicle weight and road load are transferred to the one point on the axle that is in mechanical contact with the ball bearing.

[0069] A straight roller bearing design (single, dual, or otherwise) has the benefit of distributing forces along a longer length of the axle shaft, but does not provide the stabilization benefits of the tapered angled dual roller bearings. Because straight roller bearings are flat relative the inner and outer races of the respective bearings, the vehicle may slide along the length of the straight roller bearings. Tapered angled roller bearings, on the other hand, cradle the vehicle at the point of the interface between the vehicle weight/forces and the bearings, thereby stabilizing the vehicle so that it cannot slide or move relative to the bearings and shaft.

[0070] Additionally, as shown in FIG. 7, because of the angling of bearings 632 and 636, for a direct downward force 740 on bearing assembly 630, bearings 632 and 636 direct the vehicle weight and road load forces 740 outward as forces 715 and 725, thereby distributing these forces over a longer segment of bearing-interface axle segment than the length of the bearing assembly 630 itself. For more complex forces (e.g., combined vehicle weight and road loads), tapered angled roller bearings 632 and 636 in bearing assembly 630 analogously spray the forces over a length of bearing-interface axle segment 626 that is longer than the contact interface between bearing assembly 630 and bearing-interface axle segment 626. Additionally, the combination of angled bearings is naturally suited to arrest lateral thrust forces that hold the shaft in place without the need for differential C-clips, which limit the use of locking, traction aiding, and stronger differentials

[0071] In general, bearing assembly 630 may be located as close to the wheel as possible, thereby decreasing the leverage forces exerted on bearing assembly 630 as a pivot point. Axle flange 650 may limit the minimum distance of bearing assembly 630 from the wheel.

[0072] Reinforced Flange

[0073] As shown in FIGS. 6-8, curved back surface 651 of axle flange 650 virtually intersects (because back flange surface 651 is recessed at the location of stud head 820, the curve of back flange surface 651, if continued, would “intersect”) with inner side 823 of stud head 820. Intersection with stud head 820, instead of with stud body 810, or “bottom” 822 of stud head 820, allows for use of additional material on back flange surface 651, thereby resulting in a thicker flange as flange transitions from flange outer edge 654 toward bearing assembly 630.

[0074] Reinforced flange 650 may resist flange distortion or bending during sharp curb strikes or exposure to other forces that may tend to distort the axle flange.

[0075] The shape, curve, or geometry of back flange surface 651 may be curved, functionally curved (e.g., a series linear or other geometries that functionally behaves like a curve), or designed in any other manner so that the thickness of flange 650 requires recessing of back flange surface 651 to accommodate inner side 823 of stud head 820.

[0076] The transition between outer side 824 of stud head 820 and back flange surface 651 may or may not require a transition.

[0077] The reinforced flange 650's tapered back face also resists increased loads at the flange resulting from the improved stiffness and axial rigidity of the remainder of shaft 605 and bearing assembly 630. The backside surface 651 of flange 650 is tapered toward bearing assembly journal 630 to provide increased flange support and spread impact loads evenly throughout axle segments 610, 620, and 610, 626. This also helps to transfer impact forces to the large diameter body of bearing-interface axle segment 626.

[0078] As shown FIGS. 6-8, front side 656 of flange 650 may be cupped in the center as shown by inside cup surface 655. Cupping or other patterns for material removal from front side 656 of flange 655 may result in less weight. In other embodiments, front side 656 of flange 650 may not be cupped at all, or may employ a different pattern for material removal. FIG. 11 shows an exemplary hub/flange 1100 in which front side 1110 is not cupped at all.

[0079] Assembly

[0080] FIG. 9a is an exploded elevated angle view of an exemplary bearing assembly 630. As shown in FIG. 9, bearing assembly 630 may comprise seal 640, wheel-side bearing 636, bearing housing 641, and differential-size bearing 632.

[0081] FIG. 9b is a cross-section view of an exemplary bearing assembly 630. As shown in FIG. 9, bearing assembly 630 may comprise seal 640, wheel-side bearing 636, bearing housing 641, and differential-side bearing 632.

[0082] FIGS. 10a, 10b, and 10c show an exploded view of an exemplary improved axle assembly as described herein. FIG. 10a shows an exploded assembly view of the axle, hub, mounting plate, and bearing assembly. FIG. 10b shows an assembled (not exploded) view of the components in FIG. 10a.

[0083] FIG. 10d shows a rear elevated-angle view of an exemplary improved axle as disclosed herein. FIG. 10e shows a front elevated-angle exploded view of an exemplary improved axle as disclosed herein. FIG. 10f shows a front close-up elevate angle view of an exemplary improved axle as disclosed herein.