Abstract:
A constant velocity joint includes a body, a cup, an annular array of bolts, and an annular gasket. The body has a first planar surface. The cup has a second planar surface positioned adjacent the first planar surface. The annular array of bolts interconnects the cup and body. The annular gasket is interposed between the planar surfaces of the cup and the body. The gasket has a plurality of notches defined on an outer perimeter of the gasket sized to receive the array of bolts. The notches are spaced adjacent to a corresponding bolt and define an open space between the planar surfaces around a bolt periphery. The open space enables thread-locking fluid to escape without causing displacement of the gasket or separation of the planar surfaces. A method of transmitting torque through a CV joint is also contemplated.

Description:
TECHNICAL FIELD 
       [0001]    The present disclosure relates to constant velocity joints for vehicles. 
       BACKGROUND 
       [0002]    Constant velocity joints (hereinafter “CV joints”) allow a driveshaft to transmit torque between two elements at a variable angle and constant rotational speed. CV joints may be used at shaft interfaces and transfer torque from the driveshaft to an axle. CV joints are beneficial because angles between shaft interfaces change frequently. Typically, CV joints use a spherical inner shell having six grooves wherein each groove guides a single spherical ball. This allows the CV joint to have the necessary range of motion to account for the changing angles between shaft interfaces. 
       SUMMARY 
       [0003]    A constant velocity joint includes a body, a cup, an annular array of bolts, and an annular gasket. The body has a first planar surface. The cup has a second planar surface positioned adjacent the first planar surface. The annular array of bolts interconnects the cup and body. The annular gasket is interposed between the planar surfaces of the cup and the body. The gasket has a plurality of notches defined on an outer perimeter of the gasket sized to receive the array of bolts. The notches are spaced adjacent to a corresponding bolt and define an open space between the planar surfaces around a bolt periphery. The open space enables thread-locking fluid to escape without causing displacement of the gasket or separation of the planar surfaces. 
         [0004]    A transmission includes a first shaft, a second shaft, a CV joint, and a gasket. The CV joint interconnects the first and second shafts. The CV joint has a cup and a body connected with an array of bolts wherein the first shaft splines to the body and the second shaft splines to the cup. The gasket is interposed between the cup and body and has an array of notches sized to receive the bolts defined on a gasket outer perimeter. The notches define an open space between the cup and body enabling thread-locking fluid to escape and maintain a planar engagement between a first planar surface of the cup and a second planar surface of the body. 
         [0005]    A torque transmission method includes interconnecting a body and a cup of a CV joint with a bolt array. The torque transmission method further includes interposing a gasket between the cup and body defining a notch array around an outer perimeter corresponding to the bolt array, the notch array defining a gap adjacent a corresponding bolt, the gap configured to enable thread-locking fluid to escape between the cup and body to maintain flush cup and body engagement. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0006]      FIG. 1  depicts a partial schematic view of a vehicle; 
           [0007]      FIG. 2  depicts an exploded perspective view of a CV joint; 
           [0008]      FIG. 3  depicts a front axial cross-sectional view of a CV joint body with a gasket; and 
           [0009]      FIG. 4  depicts a partial longitudinal cross-sectional view of a gasket for a CV joint. 
       
    
    
     DETAILED DESCRIPTION 
       [0010]    As required, detailed embodiments of the present invention are disclosed herein; however, it is to be understood that the disclosed embodiments are merely exemplary of the invention that may be embodied in various and alternative forms. The figures are not necessarily to scale; some features may be exaggerated or minimized to show details of particular components. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a representative basis for teaching one skilled in the art to variously employ the present invention. 
         [0011]      FIG. 1  depicts a partial schematic view of vehicle  10 . The vehicle  10  includes an engine  12 , a transmission  14 , a differential  16 , and a front axle assembly  18 . The engine  12  uses combustion to produce torque. The transmission  14  transfers torque, from the engine  12 , through the differential  16  to the axle assembly  18 . The axle assembly  18  includes an input shaft  17 , a first shaft  25 , and a second shaft  27 . Torque is output from the differential  16  to the input shaft  17  of the axle assembly  18 . The input shaft  17 , the first shaft  25 , and the second shaft  27  are mechanically connected to wheel  20  through CV joints  22 . CV joints  22  are typically used between the input shaft  17  and the first shaft  25 , as well as between the first shaft  25  and the second shaft  27  to allow torque output from the differential  16  to reach wheel  20 . 
         [0012]    The CV joints  22  account for variable angular displacement between the shaft interfaces to maintain a constant rotational speed during vehicle travel. The variable angular displacements may occur during normal suspension motion, such as during vehicle cornering or other road disturbances, for example potholes. The CV joint  22  maintains torque integrity of the vehicle  10  by allowing the first shaft  25  and the second shaft  27  of the axle assembly  18  to rotate at the same rate throughout the range of normal suspension motion. A slight angular offset between the CV joint components may distort the rotational rate between the first shaft  25  and the second shaft  27  of the axle assembly  18 . The distortion of the rotational rate may be felt throughout the vehicle  10  as noise, vibration, or harshness. 
         [0013]      FIG. 2  depicts an exploded perspective view of the CV joint  22 . The CV joint  22  includes a cup  24 , a body  26 , and a gasket  28  interposed between the cup  24  and the body  26 . A first shaft  25  splines into the body  26  and a second shaft  27  splines into the cup  24 . The first shaft  25  splines into a gear (not shown) within the body  26 . The body  26  of the CV joint  22  also includes a plurality of helical grooves (not shown). A plurality of bearings (not shown) fit within the helical grooves. The bearings are disposed around the gear allowing for rotation of the gear within the body  26 . The rotation of the bearings is defined by the shape of the grooves in the body  26 . The body  26  also includes a cage (not shown) that retains the bearings and the gear within the body  26 . The CV joint may also include a cap  23 . The cap  23  is pressed onto a first end  21  of the body  26  and covers the grooves, the bearings, the gear, and the cage when the body  26  is engaged with the cup  24 . The cap  23  prevents debris from interfering with the bearings, the grooves, the gear, or the cage and increases durability of the CV joint  22 . 
         [0014]    The cup  24  and the body  26  each have generally coplanar mating flanges that are mechanically fastened together. An array of bolts  30  may be used as mechanical fasteners to connect the body  26  to the cup  24 . A thread locking fluid  32  is typically placed on the array of bolts  30  during assembly of the CV joint  22 . The thread locking fluid  32  ensures the array of bolts  30  lock the body  26  to the cup  24  and provide a rigid connection to transfer torque through the CV joint  22 . The rigid connection allows the rotational speed of the first shaft  25  to transfer to the second shaft  27  such that the first and second shafts  25 ,  27  rotate at a constant speed. 
         [0015]    The gasket  28  includes a plurality of notches  34  defined on an outer perimeter  37  of the gasket  28 . The plurality of notches  34  correspond with the array of bolts  30 . The plurality of notches  34  may also be defined in an array defined adjacent the array of bolts  30  to allow clearance for the bolts to connect the body  26  to the cup  24 . The gasket  28  is interposed between the cup  24  and the body  26  separating a first planar surface  36  of the body  26  and a second planar surface  38  of the cup  24 . The first planar surface  36  of the body  26  may be defined on the cap  23 . In at least one embodiment, the gasket  28  may be a metallic or semi metallic material. The gasket  28  may also be formed of other materials, such as but not limited to, elastomeric, ceramic, or plastic materials. 
         [0016]    The gasket  28  may further include a plurality of tabs  41  defining a plurality of locating portions  40 . The tabs  41  of the gasket  28  are formed between the plurality of notches  34  to allow the array of bolts  30  to connect the cup  24  and the body  26 . The locating portions  40  may also be disposed in an array wherein the array of locating portions  40  are disposed between each bolt of the array of bolts  30 . The locating portions  40  correspond to a plurality of ridges  42  disposed on the cap  23 . The plurality of ridges  42  is typically a plurality of raised protrusions defined on the cap  23  to allow for movement of the bearings within the grooves. 
         [0017]    The locating portions  40  locate the gasket  28  between the cup  24  and the body  26 . The locating portions  40  prevent the gasket  28  from shifting or rotating positions between the cup  24  and the body  26  by fitting around the plurality of ridges  42 . Preventing movement of the gasket  28  between the cup  24  and the body  26  aids to prevent angular displacement of the cup  24  and the body  26 . The locating portions  40  aid the gasket  28  in maintaining a flush coplanar engagement between the cup  24  and the body  26 . A flush coplanar engagement between the cup and body  24 ,  26  of the CV joint  22  aids to ensure a constant rotational speed between the cup  24  and the body  26 . Maintaining a constant rotational speed at a variable angular offset of the first and second shafts  25 , 27  allows the CV joint  22  to maintain the torque integrity of the vehicle  10 . The gasket  28  may also be located between the cup  24  and the body  26  using an adhesive to prevent the gasket  28  from shifting or rotating positions between the cup  24  and the body  26 . 
         [0018]      FIG. 3  depicts a front view of the gasket  28  located on the first planar surface  36  of the body  26 . The gasket  28  has an outer radial diameter  48  greater than a radius  50  of a bolt centerline  52 . The plurality of notches  34  may also include an indentation  54 . The indentations  54  are defined for about 90° of a bolt periphery  46 . The plurality of notches  34  may then extend tangent from the indentations  54  to the outer radial diameter  48  of the gasket  28 . Extending tangent from the indentations  54  allows the notches  34  to widen area around the bolt periphery  46 . The outer radial diameter  48  of the gasket may extend to an outer radial diameter  51  of the first planar surface  36 . The outer radial diameter  48  of the gasket  28  may be substantially equal to the outer radial diameter  51  of the first planer surface  36  to aid in locating the gasket  28 . 
         [0019]    The plurality of tabs  41  extend to the outer radial diameter  48  of the gasket. The locating portions  40  defined on the plurality of tabs  41  are semi-annular and disposed in an array between the notches  34 . The locating portions  40  are formed from an inner radial diameter  58  and extend in the direction of the outer radial diameter  48  of the gasket  28 . The semi-annular arch of the locating portions  40  complement the plurality of ridges  42  defined on the body  26  of the gasket  28 . As described above, the plurality of ridges  42  defined on the body  26  to account for the variable angles the CV joint  22  accommodates. Therefore, depending on the size of the CV joint  22 , the size of the plurality of locating portions  40  may change to accommodate the increased size of the plurality of ridges  42   
         [0020]    Locating the tabs  41  adjacent the plurality of notches  34  and forming the outer radial diameter  48  substantially equal to the outer radial diameter  51  of the first planar surface  36  aids to increase stiffness and rigidity of the gasket  28 . The increased stiffness and rigidity of the gasket  28  aids in preventing deformation of the gasket  28  within the CV joint  22 . Preventing deformation to gasket  28  aids to ensure that there is no angular offset between the cup  24  and the body  26  within the CV joint  22 . Forming the locating portions  40  proximate the plurality of notches  34  aids to ensure the first and second planar surfaces  36 ,  38  maintain a parallel, planar orientation within the CV joint  22 . 
         [0021]      FIG. 4  depicts a partial cross-sectional view of the gasket  28  located between the cup  24  and body  26  taken along lines  4 - 4  in  FIG. 3 . The gasket  28  is shown interposed between the first planar surface  36  of the body  26  and the second planar surface  38  of the cup  24 . The interposition between the first planar surface  36  and the second planar surface  38  allows the gasket  28 , through the plurality of notches  34 , to create a gap between the body  26  and the cup  24 . Specifically, the plurality of notches  34 , through the indentations  54 , defines an open space  44  between the first planar surface  36  and the second planar surface  38 . The open space  44  is defined around a bolt periphery  46  to the indentations  54 . Increasing space around the bolt periphery  46  creates space within the CV joint  22  that may be used prevent angular offset between the cup  24  and the body  26 . 
         [0022]    For example, the thread locking fluid  32  may leak, or escape off of the bolts  30 . When the thread locking fluid  32  leaks between the cup  24  and the body  26 , it may unseat the cup  24  and body  26  such that the body  26  is seated at an angle with respect to the cup  24 . Angular offset within the CV joint  22  occurs when the body  26  is cocked at an angle with respect to the cup  24 . Angular offset between the cup  24  and the body  26  may cause excessive noise, vibration, and harshness felt through the CV joint  22 . The widened area around the bolt periphery  46  may compensate for debris, such as the thread locking fluid  32 , within the CV joint  22 . 
         [0023]    Creating open space  44  and enabling the thread locking fluid  32  to escape into the open space  44  maintains a flush and generally coplanar disposition between the first planar surface  36  and the second planar surface  38 . Open space  44  allows the thread locking fluid  32  to escape without causing separation of the parallel orientation of the first planar surface  36  and the second planar surface  38  as well as displacement of the gasket  28 . The flush disposition of the first  36  and second  38  planar surfaces eliminates noise, vibration, and harshness that may be caused by escaping thread locking fluid. Open space  44  allows the thread locking fluid  32  an area to gather without separating the parallel, planar orientation of the cup  24  and the body  26 . 
         [0024]    The parallel, planar orientation of the cup  24  and the body  26  enables the CV joint  22  to rotate at a constant speed. When the CV joint  22  rotates at a constant speed, the torque transfer through the CV joint  22  is uniform. Uniform torque transfer through the CV joint  22  provides more efficient torque transfer and reduces noise, vibration, and harshness caused by distortion within the CV joint  22 . 
         [0025]    While exemplary embodiments are described above, it is not intended that these embodiments describe all possible forms of the invention. Rather, the words used in the specification are words of description rather than limitation, and it is understood that various changes may be made without departing from the spirit and scope of the invention. Additionally, the features of various implementing embodiments may be combined to form further embodiments of the invention.