Drive shaft adaptor and coupling

#The present invention relates generally to vehicle power trains and, in particular, to a coupling system for coupling a drive shaft having a conventional universal joint to a drive train flange that is not intended to receive a conventional universal joint.

#Certain vehicles, such as the current Ford Mustang, are shipped from the factory with a drive shaft that includes at least one end that is directly bolted to an input flange forming part of either the output of the transmission or the input to the rear axle/differential. In particular, certain Ford Mustang models are delivered by the factory with a two-piece draft shaft, where the pieces of the drive shafts are interconnected by a constant velocity (CV) joint which is operative to accommodate the required relative vertical and lateral movement between the output of the transmission and the rear axle that occurs as the rear axle moves relative to the vehicle body. In the factory design, the output end of the two-piece drive shaft is directly coupled to a six bolt flange that is attached to and drives the differential pinion shaft.

#It has been found that current owners and prospective owners of these types of vehicles desire to increase the power output of the engine. It has also been found that when the power output is increased, the drive shaft must be strengthened in order to accommodate the increased torque transmitted through the drive shaft: In addition, the one-piece driveshaft offers 20 lbs. less rotating mass As a result of this market demand, after market suppliers are now offering single-piece drive shafts to replace the factory supplied two-piece drive shaft. These single piece drive shafts typically include a spicer-type universal joint and flange yoke for connecting the output end of the drive shaft to the rear axle. In order to mate the drive shaft to the rear axle flange, suppliers have created adaptors that are bolted to the CV flange and which also include four threaded bores for receiving fasteners that secure a spicer-type flange yoke to the flange. It has been found that the use of an adaptor adds cost and increased probability of imbalance to this drive shaft modification. The strength of the joint between the output end of the drive shaft and the rear axle flange may also be compromised since only four bolts are used to secure the end of the drive shaft to the rear axle flange.

#FIG. 1 is an exploded view of an apparatus constructed in accordance with a preferred embodiment of the invention for attaching and end of the drive shaft to a power train drive flange;

#FIG. 1A is an exploded view of a prior art construction;

#FIG. 2 is an exploded view showing a yoke member constructed in accordance with a preferred embodiment of the invention and a drive flange to which it is attached;

#FIG. 1 illustrates the overall construction of a yoke member 10 constructed in accordance with a preferred embodiment of the invention, which is operative to couple a drive shaft end indicated generally by the reference character 16 to a drive flange 20. FIG. 1A illustrates an example of a prior art construction. In the prior art construction, a conventional four (4) bolt spicer-type flange yoke 10a is bolted to a “pancake” adaptor 10b. The adaptor 10b includes four (4) threaded bores 11a for receiving four (4) bolts 13 that secure the flange yoke 10a to the adaptor 10b. The adaptor includes six (6) bores 11b that receive bolts (not shown) for securing the adaptor to the OEM six (6) bolt drive flange 20 that is shown in FIG. 1. To facilitate the description, the present invention will be described as it would be used to couple an output end of a drive shaft to a flange that is coupled to and drives a pinion shaft forming part of a rear axle (not shown).

#As seen in FIG. 1, the drive shaft end 16 includes a conventional spicer-type universal joint 22 which, as is conventional, comprises a cross piece 22a having two (2) pairs of journals that carry associated bearing caps 26a, 26b. One pair of bearing caps, i.e., 26a are carried by associated ears 16a of the drive shaft 16. The bearing caps 26a and associated journals define a pivot axis “x” about which the cross piece 22a pivots relative to the end of the drive shaft 16.

#The yoke member 10 of the present invention includes a pair of bearing receiving ears 10a defining bores 30, which receive bearing caps 26b carried by the other pair of journals that form part of the cross piece 22a. The bearing caps 26b and associated journals define a pivot axis “y”. Although not shown in detail, the engagement of the bearing caps 26a, 26b with the drive shaft ears 16a and yoke ears 10a, respectively is conventional. The caps are generally press-fitted into bores of the associated ears and may be retained by snap rings that are received by snap ring grooves 32 formed in the drive shaft ears 16a and the yoke ears 10a.