Abstract:
An attachment system, which couples an inboard constant velocity joint to a mating component, is disclosed. The system includes a stub shaft having an end portion and a first connector integrally formed with the end portion. The first connector includes a polygon-shaped cross-section and a first groove formed therein. A circlip is located in the first groove at the first connector. The system further includes a second connector, which engages the first connector and includes a sleeve which is sized to receive the first connector. The second connector is integrally formed within the mating component. The second connector also has a second groove formed therein which receives the circlip.

Description:
TECHNICAL FIELD 
     The present invention relates generally to driving axles, and more particularly concerns a system for attaching an inboard constant velocity (CV) joint of a driving axle to its mating component so as to facilitate assembly of the driving axle while maintaining torque transmission, concentricity, and serviceability. 
     BACKGROUND OF THE INVENTION 
     It is well known that speed variation problems can be solved by using two universal joints in series. If the joints are properly arranged, the irregularity introduced by one joint will be cancelled out by the equal and opposite irregularity introduced by the second joint. Constant velocity joints include such double universal joints as well as any joint in which the speeds of the shafts connected by the joint are absolutely equal at every instant throughout each revolution. Characteristically, a constant velocity joint includes a shaft with a universal-type coupling at each end. This arrangement is sometimes referred to as a constant velocity shaft 
     Driving axles are widely used in the automotive industry. Typically, driving axles employ inboard CV joints, an interconnecting shaft, and an outboard CV joint in order to transmit torque from a final drive unit to the driving wheels. These CV joints are used to transmit torque at varying angles caused by vertical movement of the wheels and engine movement resulting from torque reaction. In a front wheel drive vehicle, constant velocity driveshafts are used in pairs. One shaft is located on the left (driver) side of the vehicle and the other is placed on the right (passenger) side. Each shaft has an inboard or plunge coupling that connects the constant velocity shaft to the engine/transaxle and an outboard or fixed coupling that connects the shaft to a left or right wheel. The inboard and outboard couplings and shaft together comprise a constant velocity joint or driveshaft which couples the engine/transaxle shaft to the wheel shaft. In operation, the outboard coupling turns with the wheel around a “fixed” center, while the inboard coupling “telescopes” or plunges and turns at an angle sufficient to allow required movement of the automobile suspension system. 
     Constant velocity joints are also currently used in the drive trains of automotive vehicles. In such vehicles, one universal joint connects a propeller shaft to a rotary output of the transmission while a second universal joint connects the propeller shaft to a wheel. As the vehicle travels over an uneven surface or leans to one side or the other during turns, the wheels move up and down in a plane, approximately normal to the propeller shaft. Therefore, provisions are made in such joints to accommodate for the changes in the distance between the wheel and the transmission as the wheel moves up and down or the engine or transmission vibrates under high loads. 
     Currently there are three primary systems for attaching an inboard CV joint to its mating component. The first system involves plugging a CV joint into a mating component by aligning splines and sliding the splines together. The connection is secured by a standard circlip. The second system is similar to the first system with the exception that the mating component is plugged into the CV joint. The third system is also similar to the first and second systems except that the CV joint is bolted to the mating component rather than secured by a circlip. 
     Usually, on a CV joint, a rubberized boot extends axially from the open end of the housing and projects over the driveshaft. Grease is retained within the boot, and lubricates the connection between the driveshaft and the constant velocity joint. The connection is subjected to diverse stresses and strains, and effective lubrication is essential to the proper functioning of the constant velocity joint. The boot, because of its exposed location on an automobile, may be punctured, may be attacked by climatic and road conditions, or may simply wear out after extended use. At such time, as a minimum, the boot must be replaced, and, in many instances, the joint must be repaired. In order to effectuate the necessary replacement and/or repair, the driveshaft and the constant velocity joint must be disassembled. 
     The current systems for assembling CV joints and mating components are relatively inefficient because time is wasted aligning and securing CV joints and mating components. Also, current systems for disassembling CV joints and mating components are inefficient because often CV joints are not designed for disassembly and, resultantly, many CV joints must be destroyed during separation. 
     The disadvantages associated with these conventional CV joint assembly and disassembly techniques have made it apparent that a new system for CV joint construction is needed. This new system should have a guiding system to facilitate alignment of the joint and the mating component. Design of this new system should also involve creating CV joints that are easily disassembled from their respective mating components. 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to provide an improved attachment system. It is also an object of the present invention to provide an improved attachment system for applications, which include inboard constant velocity joints. 
     In accordance with the present invention, an attachment system, which couples an inboard constant velocity joint to a mating component, is disclosed. The system includes a stub shaft having an end portion and a first connector integrally formed with the end portion. The first connector includes a polygon-shaped cross-section and a first groove formed therein. A circlip is located in the first groove at the first connector. The system further includes a second connector, which engages the first connector and includes a sleeve which is sized to receive the first connector. The second connector is integrally formed within the mating component. The second connector also has a second groove formed therein which receives the circlip. 
     Additional objects and features of the present invention will become apparent upon review of the drawings and accompanying detailed description of the preferred embodiments. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of an attachment system for an inboard constant velocity joint and a mating component in accordance with one embodiment of the present invention; 
     FIG. 1A is side view of the circlip, illustrated in FIG. 1, in accordance with one embodiment of the present invention; 
     FIG. 2 is a partial sectional view of FIG. 1 along line  2 — 2 ; 
     FIG. 3 is a partial sectional view of the assembled attachment system for an inboard constant velocity joint illustrated in FIG. 2, in accordance with one embodiment of the present invention; 
     FIG. 4 is a sectional view of FIG. 3 along line  4 — 4 ; 
     FIG. 5 is a partial sectional view of an inboard constant velocity joint and a mating component in accordance with another embodiment of the present invention; 
     FIG. 6 is a partial sectional view of an inboard constant velocity joint and a mating component in accordance with another embodiment of the present invention; 
     FIG. 7 is a sectional view of FIG. 6 along line  7 — 7 ; 
     FIG. 8 is a partial sectional view of an inboard constant velocity joint and a mating component in accordance with another embodiment of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The present invention is illustrated with respect to an attachment system  10 , particularly suited to the automotive field. However, the present invention is applicable to various other uses that may require robust attachment systems, as will be understood by one skilled in the art. 
     Referring to FIGS. 1,  1 A,  2 ,  3 , and  4 , an attachment system  10  for an inboard constant velocity joint and a mating component, in accordance with one embodiment of the present invention, is illustrated. FIG. 1 illustrates a perspective view of the attachment system  10 . FIG. 2 further illustrates the attachment system  10 , illustrated in FIG. 1, along line  2 — 2 . The attachment system  10  includes a typical inboard constant velocity joint (CV joint)  12 . The CV joint  12  includes a stub shaft  16  that is integrally formed with the CV joint  12 , as will be understood by one skilled in the art. The stub shaft  16  has an end portion  18  with a first connector  20  integrally formed with the end portion  18 . The first connector  20  has a first set of splines  22 , which line the internal circumference of the first connector  20  from the edge portion  24  of the first connector  20  to a first groove  26  in the first connector  20 . 
     The first set of splines  22  protrude inward toward the central longitudinal axis  23  of the CV joint  12 . The first groove  26  is sized to receive a circlip  28  when the attachment system  10  is actuated, illustrated in FIG. 3, as will be discussed later. The first set of splines  22  are further illustrated in the cross-sectional view of FIG. 3, along line  4 — 4 , illustrated in FIG.  4 . 
     The first groove  26  ideally has a ramp portion  27 , which angles away from the end portion  18 . The ramp portion  27  facilitates disassembly of the attachment system  10 , which will be discussed later. 
     The circlip  28 , in the current embodiment, has an integrated tab design to simplify separation of components of the attachment system  10 . In FIG. 1A, a circlip  28 , with two tabs  31 , is illustrated. However, alternate designs and numbers of tabs will be evident to one skilled in the art. The tabs  31  extend substantially outward from the circlip  28  from the end portions of the circlip  28 . The circlip should be somewhat flexible such that when the tabs  31  are pressed substantially together, the diameter of the circlip  28  is partially collapsed to facilitate disassembly of the attachment system  10 , which will be discussed later. 
     A first pilot diameter section  29  with a first pilot diameter  30  forms substantially between the internal wall  32  of the first connector  20  and the first groove  26 . The first pilot diameter  30  embodied here is measurably less than the internal diameter of the first connector  20 . This first pilot diameter section  29  simplifies assembly for the attachment system  10 , which will be discussed later. 
     The attachment system  10  further includes a mating component  34 , such as an axle, transmission, or driveshaft, integrally formed with a second connector  36 . The second connector  36  has an edge portion  38  with a second pilot diameter section  39 , which has a second pilot diameter  40 , sized to couple with the first pilot diameter section  29 . A second groove  41  circumvents the external circumference of the second connector  36  between the edge portion  38  and the mating component  34 . The second groove  41  is sized to receive the circlip  28  during engagement of the attachment system  10 . Though a ramp portion like  27  is not included as part of the second groove  41 , one may alternately be added as necessary to simplify manufacturing. A second set of splines  42 , sized to couple with the first set of splines  22 , overlay the circumference of the second connector  38  between the second groove  41  and the mating component  34 . 
     Referring to FIG. 5, a partial sectional view of an attachment system  50 , in accordance with another embodiment of the present invention, is illustrated. The attachment system  50  includes a typical inboard constant velocity joint  52 . The CV joint  52  includes a stub shaft  56  that is integrally formed with the CV joint  52 , as will be understood by one skilled in the art. The stub shaft  56  has an end portion  58  with a first connector  60  integrally formed with the end portion  58 . The first connector  60  has a first set of splines  62 , which line the external circumference of the first connector  60  from the edge portion  64  of the first connector  60  to a first groove  66  in the first connector  60 . The first groove  66  is sized to receive a circlip  68  when the attachment system  50  is actuated, as will be discussed later. The first set of splines  62 , in this embodiment, continue from the first groove  66  to the side of the first connector  60  opposite the stub shaft  56 . The first set of splines  62  protrude outward from the central longitudinal axis  63  of the CV joint  52 . A first pilot diameter section  70 , with a first pilot diameter  71 , extends from the side of the first connector  60  opposite the stub shaft  56 . Ideally, the first pilot diameter section  70  is centered on the central longitudinal axis  63  of the CV joint  52 . The first pilot diameter  71  embodied here is measurably less than the diameter of the first connector  60 . This first pilot diameter section  70  simplifies assembly for the attachment system  50 , as will be discussed later. 
     The attachment system  50  further includes a mating component  74 , integrally formed with a second connector  76 . The second connector  76 , embodied here, acts as a cylindrical sleeve for the first connector  60 . The second connector  76  has a second set of splines  82 , sized to couple with the first set of splines  62 , which circumvent the internal circumference of the second connector  78 , centered on the central longitudinal axis  63  of the CV joint  52 . A second groove  80  circumvents the internal circumference of the second connector  76  and is positioned and sized to receive the circlip  68  during engagement of the attachment system  50 , which will be discussed later. A second pilot diameter section  84 , which has a second pilot diameter  86 , protrudes from the mating component  74  and is sized to couple with the first pilot diameter section  70  during attachment of the components, which will be discussed later. The second pilot diameter section  84  is substantially centered on the central longitudinal axis  63  of the CV joint  52  and is surrounded by the internal circumference of the second connector  76 . 
     Referring to FIG.  6  and FIG. 7, a partial sectional view of an attachment system  100 , in accordance with another embodiment of the present invention, is illustrated. The attachment system  100  includes a typical inboard constant velocity joint  112 . The CV joint  112  includes a stub shaft  116  that is integrally formed with the CV joint  112 , as will be understood by one skilled in the art. The stub shaft  116  has an end portion  118  with a first connector  120  integrally formed with the end portion  118 . The first connector  120  also has an internal polygon cross-section, which substantially simplifies assembly of the attachment system  100 , as will be discussed later. A first groove  126  circumvents the internal circumference of the first connector  120 . The first groove  126  is sized to receive a circlip  128  when the attachment system  100  is actuated, as will be discussed later. 
     The attachment system  100  further includes a mating component  134 , integrally formed with a second connector  136 . The second connector  136  has an external polygon cross-section, which is sized to couple with the internal polygon cross-section  137  of the first connector  120 . The internal polygon cross-section  137  is further illustrated in the sectional view of FIG. 3, along line  4 — 4 , illustrated in FIG. 7. A second groove  140  circumvents the external polygon circumference of the second connector  136 . The second groove  140  is sized and positioned to receive the circlip  128  during engagement of the attachment system  100 , which will be discussed later. 
     Referring to FIG. 8, a partial sectional view of an attachment system  150 , in accordance with another embodiment of the present invention, is illustrated. The attachment system  150  includes a typical inboard constant velocity joint  152 . The CV joint  152  includes a stub shaft  156  that is integrally formed with the CV joint  152 , as will be understood by one skilled in the art. The stub shaft  156  has an end portion  158  with a first connector  160  integrally formed with the end portion  158 . The first connector  160  also has an internal polygon cross-section  137 , which substantially simplifies assembly of the attachment system  150 , as will be discussed later. A first groove  166  circumvents the internal circumference of the first connector  160 . The first groove  166  is sized to receive a circlip  168  when the attachment system  150  is actuated, as will be discussed later. 
     The attachment system  150  further includes a mating component  174 , integrally formed with a second connector  176 . The second connector  176 , embodied here, acts as a cylindrical sleeve for the first connector  160 . The second connector  176  has an external polygon cross-section, which is sized to couple with the internal polygon cross-section  177  of the first connector  160 . A second groove  180  circumvents the internal polygon circumference of the second connector  176 . The second groove  180  is sized and positioned to receive the circlip  168  during engagement of the attachment system  150 , which will be discussed later. 
     In operation, using the embodiment in FIG.  1  and FIG. 2 to illustrate, the first connector  20  is coupled to the second connector  38  by sliding the first connector  20  over the second connector  38 , as will be understood by one skilled in the art. The embodiment illustrated in FIG. 2 has two sets of splines  22 ,  42 . The splines  22 ,  42  maintain concentricity during assembly and guide the connectors  20 ,  36  together. The fully assembled attachment system  10  from FIG.  1  and FIG. 2 is illustrated in FIG.  3 . When assembling the connectors  20 ,  38 , the splines  22 ,  42  must align. Therefore, the pilot diameters  30 ,  40  guide the connectors  20 ,  36  together and maintain a sufficient amount of concentricity while the splines  22 ,  42  are aligning. Additionally, the designs of the first connector  20  and the second connector  36  facilitate maintenance of torque transmission. In other words, when connected, the connectors  20 ,  36  maintain a substantially constant torque between them. 
     The connectors  20 ,  36  decouple by first implementing a retention device. In other words, the tabs  31  are pressed together to partially collapse the circlip  28 . This releases tension between the first connector  20  and the second connector  36 , as will be understood by one skilled in the art. Next, the CV joint  12  slidibly removes from the mating component  34 . During this step, the circlip  28  slides over the ramp portion  27  of the first groove  26 . A typical connector for a CV joint has grooves with relatively steep sides that require greater effort over which to move. The ramp portion  27  reduces effort necessary for disassembly. Subsequently, the concentricity controller (here the splines  22 ,  42 ) is disengaged and the attachment system  10  is disassembled. 
     The embodiment illustrated in FIG. 4, alternately, has connectors  120 ,  136  with polygon cross-sections for achieving the same concentricity control. However, the polygon cross-section design does not require a separate set of pilot diameters as does the spline design in FIG. 1 because the polygon connectors  120 ,  136  are relatively simple to align. 
     While the invention has been described in connection with one or more embodiments, it should be understood that the invention is not limited to those embodiments. On the contrary, the invention covers all alternatives, modifications, and equivalents, as may be included within the spirit and scope of the appended claims.