Steerable driving axle

#The present invention relates generally to a driving axle assembly for a wheeled vehicle and, in particular, to a steerable driving axle assembly including a centrally located differential assembly secured to a vehicle frame member and connected to drive a pair of steerable wheel assemblies which are independently suspended by a pair a leaf springs.

#Steerable driving axle assemblies having independently suspended wheel assemblies are well known. Examples of such steerable wheel assemblies are disclosed in U.S. Pat. Nos. 2,796,943 to Rolt et al and 3,155,186 to Cadmus et al. While the steerable driving axle assemblies disclosed in these patents are suitable for certain applications, there has been a need for a steerable driving axle which is provided with relatively high ground clearance and incorporates a rugged suspension system for off-road use

#The present invention relates to a unique steerable driving axle which includes a rugged leaf spring suspension system and has a structure which provides for relatively high ground clearance. The driving axle of the present invention is especially suited for a vehicle adapted for off road use.

#FIG. 1 is a rear elevational view of a steerable driving axle assembly according to the preferred embodiment of the invention;

#FIG. 2 is a partial sectional view of the mechanical interconnection between the fixed differential gearbox and the inner ends of the moveable axle tube and axle shaft, taken along the line 2--2 in FIG. 1;

#FIG. 3 is a partial sectional view which illustrates the interconnection between the wheel assembly and the outer ends of the axle tube and the axle shaft, along with the planetary gearbox which is incorporated in the wheel assembly;

#Referring to FIG. 1, there is shown a rear elevational view of a steerable drive axle 10 according to the present invention. Since the steerable drive axle 10 is symmetrical about a centrally located differential assembly 11, only the left hand portion of FIG. 1 will be discussed in detail. When referring to identical or mirror-image components located on the right hand portion, reference numerals identical to those which designated similar components on the left side will be used with the addition of alphabetic subscripts. Also, since the internal components of the differential assembly 11 are well known to those skilled in the art, they will not be discussed herein.

#The differential assembly 11 includes an outer case 12. A differential input shaft 14 extends outwardly from a central portion of the differential case 12 and is provided with an input yoke assembly 16 for attachment to an engine drive member (not shown). The differential case 12 includes a pair of collars 18 and 18a which are adapted to be attached to a vehicle chassis (not shown) by conventional mounting blocks (not shown) for supporting the differential assembly. The outer ends of the collars 18 and 18a are secured to fixed yoke members 20 and 20a which are pivotally coupled to the inner ends of axle tubes 22 and 22a at joint locations 24 and 24a respectively. The details of the pivotal connection at the location 24 are illustrated in FIG. 2 and will be discussed in more detail hereinafter.

#The axle tubes 22 and 22a are provided respectively with spring pads 26 and 26a. The spring pads 26 and 26a are utilized to support leaf springs 28 and 28a, (shown in section in FIG. 1) which are attached to the vehicle chassis (not shown) in a conventional fashion. The springs 28 and 28a are attached to the spring pads 26 and 26a by conventional spring shackles 30 and 30a. As will be discussed in more detail below with reference to FIGS. 4 and 5, the spring pads 26 and 26a are rotatably mounted on the axle tubes 22 and 22a such that the associated leaf springs can pivot about a horizontal axes perpendicular to the longitudinal axes of the axle tubes. Thus, the springs will not be subjected to torsional forces due to the pivoting movement of the axle tubes 22 and 22a.