Patent Application
20050250585
1. Field of the Invention
The present invention generally relates to a power transfer system for a motor vehicle, and more particularly, relates to an improved propeller shaft having an in vehicle installation error proofing method to ensure proper installation of the propeller shaft in the vehicle drive line.
2. Description of Related Art
There are generally four main types of automotive drive line systems. More specifically, there exists a full time front wheel drive system, a full time rear wheel drive system, a part time four wheel drive system, and an all wheel drive system. Most commonly, the systems are distinguished by the delivery of power to different combinations of drive wheels, i.e., front drive wheels, rear drive wheels, or some combination thereof. In addition to delivering power to a particular combination of drive wheels, most drive systems permit the respectively driven wheels to rotate at different speeds. For example, the outside wheels must rotate faster than the inside drive wheels, and the front drive wheels must normally rotate faster than the rear wheels.
Drive line systems also include one or more Cardan (universal) and constant velocity joints (CVJ's). Cardan joints are the most basic and common type joint used for example, in prop shafts. Although highly durable, Cardan joints are typically not suited for applications with high angles (e.g., greater than 2 degrees) because of their inability to accommodate constant velocity rotary motion. Constant velocity joints, in contrast, are well known in the art and are employed where transmission of a constant velocity rotary motion is desired or required. For example, a tripod joint is characterized by a bell shaped outer race (housing) disposed around an inner spider joint which travels in channels formed in the outer race. This spider shape cross section of the inner joint is descriptive of the three equal spaced arms extending therefrom which travel on the tracks of the outer joint. Part spherical rollers are featured on each arm.
One type of constant velocity universal joint is a plunging tripod type, characterized by the performance of end motion in the joint. Plunging tripod joints are currently the most widely used in board (transmission side) joint in front wheel drive wheels, and particularly in the prop shafts found in rear wheel drive, all wheel drive and four wheel drive vehicles. A common feature of tripod universal joints is their plunging or end motion character. Plunging tripod universal joints allow the interconnection shafts to change length during operation without the use of splines which provoke significant reaction forces thereby resulting in a source of vibration and noise. Other common types of constant velocity joints are the plunging VL or cross groove type joint which consists of an outer race and inner race drivably connected through balls located in circumferentially spaced straight or helical grooves alternately inclined relative to a rotational axis. A high speed fixed joint is another type of constant velocity well known in the art and used where transmission of high speed is required. The disc style constant velocity fixed joint is another type of joint known in the prior art. This joint has an outer joint member open on both ends and a cage is assembled from the end opposite the end towards which the cage is urged by the ball expulsion forces under articulated load conditions. The prior art also includes a mono block constant velocity fixed joint also known as a mono block high speed fixed joint. The outer joint part is a bell shaped member having a closed end.
Drive line systems also include one or more ball spline joints which include a plurality of balls enclosed within a cage to permit rotation around inner and outer respective races. Like constant velocity joints, ball spline joints are adapted to accommodate plunge in the axial direction, i.e., end wise movement. However, unlike constant velocity joints, ball spline joints do not permit articulation at angle.
A typical drive line system incorporates one or more of the above joints in an all wheel drive or traditional four wheel drive system. In an all wheel drive systems, such joints are used to connect a pair of propeller shafts to a power take off unit and a rear driveline module, respectively. These propeller shafts function to transfer torque to the rear axle in rear wheel and all wheel drive vehicles. Similarly, in a traditional four wheel drive system, such joints are used to connect a propeller shaft between a transfer case and a front axle.
In the prior art there have been problems with the insertion and installation of a propeller shaft having a high speed fixed joint on one end and a VL plunging joint on the opposite end. The problem occurs when the shaft is installed into the vehicle backwards because both the high speed fixed joint and the VL plunging joint have the same outer diameter and bolt PCD. If the shaft is installed in the vehicle backwards, it may lead to damage of the VL plunging joint or the high speed fixed joint. Furthermore, the driveline system will not operate as designed if the prop shaft is installed backwards.
Therefore, there is a need in the art to provide a propeller shaft having an in vehicle installation error proofing method to insure that the prop shafts are installed in the correctly aligned position within the driveline of the automotive vehicle. There also is a need in the art for an improved cover, including a mechanical stop to ensure proper installation of the prop shaft within the driveline of the automotive vehicle.
One object of the present invention is to provide an improved drive shaft for use in a motor vehicle.
Another object of the present invention is to provide an improved constant velocity joint for use in a prop shaft of an automotive vehicle.
It is still another object of the present invention to provide a constant velocity joint having a mechanical stop to prevent the constant velocity joint and prop shaft from being installed backwards in the driveline of a vehicle.
It is still another object of the present invention to provide an improved flange for use in a prop shaft of an automotive vehicle.
To achieve the foregoing objects a propeller shaft for use in a vehicle is disclosed. The propeller shaft includes a fixed constant velocity joint for use on one end of the shaft. The propeller shaft includes a plunging constant velocity joint on an opposite end of the shaft with one of the constant velocity joints having a mechanical stop to prevent backwards installation of the shaft within the vehicle.
One advantage of the present invention is that it provides an improved prop shaft.
Still another advantage of the present invention is that provides a propeller shaft with an in vehicle installation error proofing method.
Yet a further advantage of the present invention is that it provides an improved constant velocity joint for use with a prop shaft.
Yet another advantage of the present invention is the use of a mechanical stop with a constant velocity joint to prevent backwards installation of a prop shaft in an automotive vehicle.
Still another advantage of the present invention is a modified flange to cooperate and engage with modified grease cover of a constant velocity joint to allow proper installation of a prop shaft in an automotive vehicle.
Other objects, features and advantages of the present invention may become apparent from the subsequent description, taken in conjunction with the accompanying drawings.
Referring to the drawings, there is shown generally a representative diagram of an operative wheel drive system 12 of a motor vehicle 10. The drive system 12 comprises a pair of front half shaft assemblies 14, 16. The front half shaft assemblies 14, 16 are connected to a front differential 18. Connected to front differential 18 is a power take off unit 20. The power take off unit 20 is operatively connected to a high speed fixed joint 22. Operatively connected to the high speed fixed joint 22 is a front propeller shaft assembly 24. Operatively connected to front prop shaft assembly 24 is a VL style plunging constant velocity joint designated as reference numeral 26. Connected to the VL style constant velocity joint 26 is a rear prop shaft assembly 28. The rear prop shaft assembly 28 is connected on one end to a Cardan joint assembly. The Cardan joint assembly may be operatively connected to a speed sensing torque device 30. The speed sensing torque transfer device 36 is operatively connected to a rear differential assembly 32. A pair of rear half shaft assemblies 34, 36 are each connected to the rear differential assembly 32. As shown in
The front half shaft assemblies 14, 16 are comprised of fixed constant velocity joints 42, and an interconnecting shaft in a plunging style constant velocity joint 44. The plunging style constant velocity joints 44 are operatively connected to the front differential 18. The plunging style constant velocity joints 44 are plug in style in this embodiment. However, any style of constant velocity joint half shaft assembly, may be used depending upon the application. As shown in
The power take off unit 20 is mounted to the face of the transmission and receives torque from the front differential 18. The transmission is operatively connected to the engine of the motor vehicle. The power take off unit 18 has the same gear ratio as the rear differential 32 and drives the front prop shaft through the high speed fixed joint 22 from the front differential axis.
A high speed fixed joint 22 is connected at one end of the power take off unit 18 and at the other end to a front prop shaft 24. A VL type plunging constant velocity joint 26 is similarly connected at one end to the rear prop shaft 28 and at the other end to front prop shaft 24. The high speed fixed joint 22 may have a revolution per minute capacity of 6000 RPM's with the preferable range of three to five thousand RPM's, a torque capacity of five to fifteen hundred Newton meters, but the preferred capacity of six to seven hundred Newton meters and an inner capacity of up to 15 degrees with a preferable capacity of three to six degrees. Of course, the drive system may use other constant velocity joints and/or Cardan joints or universal joint technology at this connection. However, a high speed fixed joint is preferred.
The high speed fixed joint 22 includes a boot 50 which is utilized to enclose grease (not shown) required for lubrication of the high speed fixed joint 22. The front prop shaft 24 in the present invention is manufactured from steel providing a very low run up and critical high speed capacity higher than the second engine order. The front prop shaft 24 is operatively connected to the high speed constant velocity joint 22 by fasteners 52. The front prop shaft 24 has a flange 54 extending out which is connected to a constant velocity joint by the fasteners. The high speed fixed joint similarly includes a flange 54 extending out which is connected to the front prop shaft 24 by fasteners 52.
On the opposite end of the front propeller shaft 24 is a plunging VL constant velocity joint 26. The plunging VL constant velocity joint 26 includes an outer race 55 with an inner race 56 arranged within the outer race 55. The plunging constant velocity joint 26 also includes a cage 58 for supporting and locating a plurality of rolling elements 60 between an inner surface of the outer race 55 and an outer surface of the inner race 56. The plunging constant velocity joint 26 has a stub shaft 62 rotatably fixed to an inner bore of the inner race 56. The plunging VL constant velocity joint 26 also includes a flange 64 with the flange 64 connected to one end of the front prop shaft 24 and to the outer race 55 of the VL plunging constant velocity joint 26 on an opposite end thereof. The flange 64 has a plurality of orifices 66 therein that will align with the plurality of orifices 68 through a surface of the outer race 55 of the VL plunging constant velocity joint 26 and allow for fasteners 70 to secure the VL plunging constant velocity joint 26 to the flange 64 and hence the front prop shaft 24 of the automotive vehicle.
The high speed fixed constant velocity joint 22 as described above is located on the front end of the propeller shaft 24. The high speed fixed constant velocity joint 22 includes an outer race 72 with an inner race 74 arranged therein. A cage 76 and a plurality of rolling elements 78 are arranged between the inner race 74 and outer race 72 for transfer of constant velocity rotary motion through the high speed fixed joint 22. The high speed fixed constant velocity joint 22 includes a flange 54 that is connected to the power take off unit 18 on one end and to the outer race 72 of the high speed constant velocity joint 22 on the opposite end. The outer race 72 of the constant velocity joint 22 has a plurality of orifices 80 therethrough that mate with and align with a plurality of orifices through the flange 54 of the high speed constant velocity joint 22. Fasteners 84 will connect the high speed constant velocity joint 22 to the flange 54 during installation of the constant velocity joint.
The high speed constant velocity joint 22 includes a grease cap 86 on one end thereof. The plunging VL constant velocity joint 26 also includes a grease cover 88 in contact with the outer race 55 and flange 64 of the VL constant velocity joint 26. The grease covers 86, 88 will ensure the lubricant stays within the VL plunging constant velocity joint 26 and the high speed fixed joint 22 for proper lubrication of the joints. According to the present invention the VL plunging constant velocity joint 26 has a modified grease cover 88 arranged to any known caps in the prior art. In particular, as shown in
As shown in
As shown in
The present invention has been described in an illustrative manner. It is to be understood that the terminology which has been used is intended to be in the nature of words of description rather than of limitation.
Many modifications and variations of the present invention are possible in light of the above teachings. Therefore, within the scope of the appended claims, the present invention may be practiced otherwise than as specifically described.
