Rotary shafts – gudgeons – housings – and flexible couplings for ro – Coupling accommodates drive between members having... – Coupling transmits torque via radially directed pin
Reexamination Certificate
2001-11-19
2002-09-10
Binda, Greg (Department: 3679)
Rotary shafts, gudgeons, housings, and flexible couplings for ro
Coupling accommodates drive between members having...
Coupling transmits torque via radially directed pin
C464S171000, C180S908000
Reexamination Certificate
active
06447398
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to universal joint assemblies and more particularly pertains to a reduced length universal joint assembly for optimizing the manner of transferring torque from a rear axle of a vehicle to the chassis of the vehicle.
2. Description of the Prior Art
In racing vehicles, such as midget- and sprint-type open wheel racing cars, the desire to obtain the fastest travel times about a race track requires maximizing the speed of the racing car and optimizing the handling capability of the racing car as it moves around the track so that the speed generated is not wasted due to the driver's inability to keep the car moving along the desired (e.g., shortest) path about the track.
The drivetrain of a racing car differs from a conventional automobile in that a portion of the racing car drivetrain forms a significant element of the suspension that locates the rear axle and wheels on the racing car. A common drivetrain of a racing car typically includes a motor, a driveline, and a rear end assembly. The rear end assembly includes a rear axle housed in a rear axle housing (which actually comprises two rear axle segments), various gears connected to the rear axle segments, and rear wheels mounted on the outer ends of the rear axle segments. The driveline includes a drive shaft, and a tubular housing that is rigidly connected to the rear axle housing. The drive shaft rotationally connects the crankshaft of the motor to the gears in the rear end assembly. The tubular housing of the driveline, often referred to as a torque tube, is rigidly connected to the rear axle housing and extends forwardly from the rear axle housing. The torque tube is joined to the chassis of the racing car by an engine mounting plate, which typically has the engine directly mounted on its forward side. Typically, a forward end of the torque tube is mounted on a rearward side of the engine mounting plate by a swivel joint. The swivel joint is generally comprised of a torque ball mounted on the forward end of the torque tube, and the torque ball is seated in socket formed in an adaptor housing that is mounted on a rearward side of the engine mounting plate. The engine mounting plate is located toward the center of the chassis of the racing car, and forms a significant link for locating the rear end assembly on the car.
The large amount of power generated by the engine of the racing car is transferred by the driveline to the rear axle. This significant power applied to the rear axle and the wheels produces a reactionary torque that acts on the rear axle housing in a rotational direction opposite to the direction of the rotation of the rear wheels. This reactionary torque is in turn applied to the torque tube of the driveline. The forward end of the torque tube is thus forced upward by the reactionary torque of the rear axle. The weight of the race car (e.g., the engine, chassis, and driver) acts downwardly on the forward end of the torque tube through the engine mounting plate and the adaptor housing to counter the reactionary torque, and to thereby keep the front wheels of the car in sufficient contact with the ground surface to facilitate effective steering of the car for maximizing the handling of the car.
It is thus desirable to maximize the transfer of the downward force of the weight of the car to the torque tube and thus to the rear end assembly to counter the lifting of the torque tube as a result of the reactionary torque acting on the rear axle housing.
The design of conventional racing car drivelines have remained virtually unchanged for approximately twenty years, except for the substitution of lighter weight materials for the various driveline components, and thus the ability to counter the lifting torque of the torque tube on the car has also remained relatively the same. In contrast, the power available from the engines has consistently increased, while the weight of the components of the cars has decreased. The desired increases in the power of the car applied to the rear wheels thus has the disadvantage of increasing the reactionary lifting torque applied to the chassis of the car through the torque tube, and thus can cause degradation of the handling characteristics of the car.
SUMMARY OF THE INVENTION
It is believed that one way of improving the handling characteristics of the racing car in the face of ever-increasing amounts of horsepower is to maximize the portion of the overall weight of the car that may be applied to the torque tube to counter the reactionary torque transferred from the rear axle housing to the torque tube. One manner of accomplishing this goal is to move the swivel joint of the torque tube forward, and thus closer to the center of the car and, most importantly, toward the heaviest component of the car, namely the engine. Moving the swivel joint forward (with the rear axle remaining in relatively the same position) increases the length of the torque tube, and thus increases the length of the lever arm on which the force of the weight of the car is applied to the rear axle housing to counter the reactionary torque.
However, minimization of the distance between the swivel joint of the torque tube and engine mounting plate has been restricted by the relative length of the universal joint in the driveline that connects the crankshaft to the drive shaft. The center of swivel of the universal joint dictates the location of the center of swivel of the torque ball, as these centers of swivel must be coincident to avoid binding of the swivel joints. Thus, the ability to move the position of the torque ball swivel toward the engine is dictated in part, and limited by, the ability to move the position of the universal joint toward the engine. Conversely, the ability to shorten the distance between the end of the universal joint mounted on the crankshaft and the center of swivel of the universal joint has been severely limited by the need to retain as great of a degree (or angle) of swivel as possible without binding or interference of the joint components. As noted above, the design of the universal joints utilized in the drivelines of racing cars has remained virtually the same for two decades.
The invention contemplates a universal joint with a relatively shortened length as compared to those heretofore known and used in applications such as those described above, especially in the distance between the crankshaft mounting surface and the center of swivel of the joint, to thereby permit a commensurate shortening of the distance between the engine mounting plate and the center of swivel of the torque ball. To attain this, the present invention generally comprises a joint assembly including a yoke for connecting to an end of the drive shaft. The yoke includes a shaft portion for mounting on the drive shaft and a pair of yoke ears mounted on the shaft portion. The joint assembly includes a flange for connecting to an end of the crankshaft of the engine. The flange includes a flange plate for mounting against the end of the crankshaft. The flange plate has a first side and a second side with the first side being adapted for positioning adjacent to the crankshaft. The flange includes a pair of flange ears mounted on the flange plate. The flange ears extend from the second side of the flange plate. A spider rotatably joins the yoke and flange together. A pair of cupped areas is formed in the flange plate for providing space for each of the yoke ears of the yoke. A portion of the second side of the flange plate defines a plane, and the cupped areas extend through the plane of the second side and into the flange plate. A portion of each of the yoke ears extends substantially adjacent to the plane of the second side of the flange plate when axes of rotation of the yoke and flange are collinear.
There has thus been outlined, rather broadly, the more important features of the invention in order that the detailed description thereof that follows may be better understood, and in order that the present contribution to the a
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