Abstract:
A constant velocity joint boot assembly has a boot can connected to an outer race of the joint. The boot can receives a portion of a boot. The thickness of the boot may be changed in different areas to result in different boot performances. A sleeve is connected to the inner race. A portion of the sleeve may have a complementary shape to a portion of the boot, also to result in different boot performance. A clamp may be located over a portion of the boot to secure it to the sleeve.

Description:
RELATED APPLICATIONS 
       [0001]    This application claims priority to and the benefit of pending U.S. Provisional Application Ser. No. 62/028,847 filed on Jul. 25, 2014, which is incorporated by reference in its entirety. 
     
    
     FIELD 
       [0002]    The device described herein relates to a boot assembly for a constant velocity joint. 
       BACKGROUND 
       [0003]    Boots are well-known devices used to enclose an end of a constant velocity joint. Boots keep out dirt, debris and moisture from the joint and keep lubricant in the joint. 
         [0004]    One example of a prior art boot  10  for a joint  12  is depicted in  FIG. 1 . The joint  12  comprises an inner race  14 , an outer race  16 , a cage  18  and at least one ball  20  within the cage  18 . 
         [0005]    The boot  10  encloses one end of the joint  11  The boot  10  is connected at one end to the outer race  16  with a boot can  22 . A boot bead  26  is formed on the boot can  22  to capture the boot  10 . The boot bead  26  is generally round and formed inwardly. A boot can crimp  28  also helps hold the boot  10  in place. The boot can crimp  28  is also formed inwardly. The boot  10  is connected at the other end to a shaft  24 , such as by a clamp  30 . 
         [0006]    The size of the boot  10  used in  FIG. 1  is characterized by boot length L, boot can length LL, boot can inner diameter Ø Db and the thickness of the boot  10 . Boot length L, boot can length LL and boot can inner diameter Ø Db are determined by the required maximum static articulation angle capability, which is depicted in  FIG. 2 . More particularly, boot length L is determined in a way that boot length L in a joint assembly state as shown in  FIG. 1  is equivalent to the boot length of an extended boot region  32  and the boot length of a contracted boot region  34  at a maximum joint angle. 
         [0007]    Boot thickness for the boot  10  of  FIGS. 1 and 2  is depicted in  FIG. 3 . The boot  10  generally has a round shape RR with an angle a from the horizontal, where the thickness T 1  of an upper slope portion  36 , is equal to the thickness T 2  of a concave portion  38 , which is equal to the thickness T 3  of a lower slope portion  40 . The joint boot thickness T 1 , T 2 , T 3  is determined by taking into consideration boot radial and axial stiffness related to potential high risk boot failure modes, such as boot inversion and boot folding, both of which mainly occur at high joint internal pressures. Line Ø Dg represents the typical grease fill level for such a joint  12 . 
         [0008]      FIGS. 4-8  depict another prior art constant velocity joint  42  with a boot  44 . The joint  42  comprises an inner race  46 , an outer race  48 , a cage  50  and at least one ball  52  within the cage. This joint  42  uses a sleeve  54  that couples the inner race  46  with a pinion shaft  56 . A nut  58  connects the sleeve  54  to the pinion shaft  56 . 
         [0009]    The sleeve  54  in such a direct pinion mount design has a larger diameter Ds 1  than a tube shaft diameter Ds in a non-direct pinion mount design, such as shown in  FIGS. 1-3 . Therefore, the boot can inner diameter Db 1  should increase by the difference between Ds 1 −Ds to have the equivalent maximum static joint angle capability to that of a non-direct pinion mount design, such as in  FIGS. 1-3 . This results in a higher grease pressure acting on the direct pinion mount boot  44  compared with the pressure on the boot  10  depicted in  FIG. 1 . 
         [0010]    The boot length L 1  is limited by the nut  58  as shown in  FIG. 4 , therefore, it is more difficult to make the boot length L 1  equivalent to the non-direct pinion mount joint boot length L depicted in  FIG. 1 . This results in a boot can inner diameter Db 1  being bigger to have the equivalent boot overall length required for achieving a maximum joint angle compared to the design in  FIG. 1 . 
         [0011]    Further, the limited boot axle length L 1  cannot provide a sufficient press fit contact portion  62  between the sleeve  54  and the boot  44 , which causes region  64  near a boot groove seat  66  to be bumped up and tilted toward the boot groove seat  66  by a crimping force of a boot clamp  68  acting on the boot clamp seat inside corner  70 , which can be appreciated from  FIGS. 6 and 7 . 
         [0012]      FIG. 8  depicts a direct pinion mount joint  42  having uniform boot thickness (T 21 =T 22 =T 23 ) that has folded/self-contacted at a boot contacted region  78  as a result of the wrong boot thickness for this design. The figure also depicts the boot  44  being severely bent at an edge of the boot can crimp  80  by high grease pressure while operating at a high temperature, a high operating speed and at a high operating angle. 
         [0013]    In view of the disadvantages of attempting to apply a non-direct pinion mount boot system to a direct pinion mount boot system, a new design is required. 
       SUMMARY 
       [0014]    A constant velocity joint boot assembly has a boot can, a boot, a sleeve and a clamp. One part of the boot can is connected to an outer race and the other part of the boot can is cantilevered from the outer race. The boot can may have a crimp head for receiving the boot. The boot may have different regions where the thickness of the region changes, such as decreases from one to the next. The sleeve has one portion connected to the inner race and another portion extending from the inner race. The portion extending from the inner race may have a complementary shape to the boot. The clamp is used to secure the boot to the sleeve. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0015]      FIG. 1  is a partial side view cross section of a first prior art constant velocity joint; 
           [0016]      FIG. 2  is a partial side view cross section of a portion of the joint of  FIG. 1  at a maximum articulation angle; 
           [0017]      FIG. 3  is a partial side view cross section of a portion of the joint of  FIG. 1 ; 
           [0018]      FIG. 4  is a second partial side view cross section of a prior art constant velocity joint; 
           [0019]      FIG. 5  is a partial side view cross section of a portion of the joint of  FIG. 4  at a maximum articulation angle; 
           [0020]      FIG. 6  is a partial side view cross section of a portion of the joint of  FIG. 4 ; 
           [0021]      FIG. 7  is a partial side view cross section of a portion of the joint of  FIG. 4 ; 
           [0022]      FIG. 8  is a partial side view cross section of a portion of the joint of  FIG. 4 ; 
           [0023]      FIG. 9  is a partial side view cross section of a first embodiment of a constant velocity joint and boot system; 
           [0024]      FIG. 10  is a partial side view cross section of a portion of the joint in  FIG. 9 ; 
           [0025]      FIGS. 10A-10C  are partial side view cross-sections of portions of the joint in  FIG. 9 ; 
           [0026]      FIG. 11  is a partial side view cross section of a second embodiment of a constant velocity joint and boot system; 
           [0027]      FIG. 12  is a partial side view cross section of a third embodiment of a constant velocity joint; 
           [0028]      FIG. 12A  is a partial side view cross section of a detail of the joint in  FIG. 12 ; 
           [0029]      FIG. 13  is a partial side view cross section of a fourth embodiment of a constant velocity joint and boot system; 
           [0030]      FIGS. 14A-14C  comprises three partial side view cross sections of portions of the joint in  FIG. 13 ; 
           [0031]      FIG. 15  is a partial side view cross section of a fifth embodiment of a constant velocity joint and boot system; 
           [0032]      FIG. 16  is a partial side view cross section of a sixth embodiment of a constant velocity joint and boot system; 
           [0033]      FIG. 17  is a partial side view cross section of a seventh embodiment of a constant velocity joint boot system; 
           [0034]      FIG. 17A  is a partial side view cross section of a detail from  FIG. 17 ; 
           [0035]      FIG. 18  is a partial side view cross section of an eighth embodiment of a constant velocity joint boot system; 
           [0036]      FIG. 19  is a partial side view cross section of a ninth embodiment of a constant velocity joint boot system; and 
           [0037]      FIG. 19A  is a partial side view cross section of a detail from  FIG. 19 . 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0038]    It is to be understood that the invention may assume various alternative orientations and step sequences, except where expressly specified to the contrary. It is also to be understood that the specific devices and processes illustrated in the attached drawings, and described in the following specification are simply exemplary embodiments of the inventive concepts defined in the appended claims. Hence, specific dimensions, directions or other physical characteristics relating to the embodiments disclosed are not to be considered as limiting, unless the claims expressly state otherwise. 
         [0039]    Turning to  FIG. 9 , one embodiment of a boot system  82  for a direct pinion mount joint  84  is depicted. The joint  84  comprises an inner race  86 , an outer race  88 , a cage  90  and at least one ball  92  within the cage  90 . A tube  94  is connected, such as by welding, to the outer race  88 . A first end  96  of a sleeve  98  is connected, such as by splines  100 , to the inner diameter of the inner race  86 . A second end  102  of the sleeve  98  receives a pinion shaft  104  therein, such as through a splined connection  106 . A nut  108  connects the pinion shaft  104  to the sleeve  98 . 
         [0040]    A boot can  110  is depicted in  FIGS. 9 and 10 . The boot can  110  has a first end portion  112  connected to the outer race  88  and a second end portion  114  that is cantilevered over the joint  84 . More particularly, the second end portion  114  is cantilevered over a portion of the sleeve  98 . 
         [0041]    As best seen in  FIGS. 10 ,  10 A and  10 C, the second end portion  114  comprises an outwardly angled, planar portion  116  and a boot can crimp head  118  at an end of the angled, planar portion  116 . The boot can crimp head  118  first extends radially outward from the angled, planar portion  116  before it curves around on itself to create a semi-hemispherical hollow portion  120 . A boot bead  121  is located in the portion  120 . The boot bead  121  has an outward radially extending portion with a complementary shape to the portion  120 . 
         [0042]    One end  122  of a straight portion  124  of the can  110  connects with the semi-hemispherical hollow portion  120 . The boot can  110  terminates at the other end  126  of the straight portion  124 . The straight portion  124  is located radially inward from the angled, planar portion  116 . A gap  128  separates the angled, planar portion from the straight portion  124 . 
         [0043]    With continued reference to  FIG. 10 , it can be seen that the boot thickness smoothly decreases from an upper slope region  130 , through a concave region  132  down to a lower slope region  134 . The range of thicknesses of the upper slope region may be generally designated as T 31 , the range of thicknesses of the concave region  132  may be designated T 32  and the range of thicknesses of the lower slope region  134  may be generally designated as T 33 . The decrease in thickness is represented by T 31 &gt;T 32 &gt;T 33 . The decrease in thickness from the upper slope region  130  to the lower slope region  134  reduces boot radial deformation caused by high grease pressure anywhere in the boot  136 , but is particularly effective at the upper slope region  130 . 
         [0044]    The boot  136  also includes a boot stopper  138  in the upper slope region  130 , as shown in  FIG. 10A . More particularly, the boot stopper  138  is located on an outside boot surface  140  that abuts, or is adjacent, the boot can straight portion  124 . The boot stopper  138  comprises a radially inward step  142  into the boot  136  that reduces the thickness of the boot  136  at that location of the step  142 . The boot stopper  138  prevents radial boot deformation via the direct contact with the boot can  110 , particularly when the boot  136  is significantly deformed. 
         [0045]    As can be appreciated by  FIG. 10A , a press load δ 2  is used to locate the upper slope region  130  into the boot can crimp head  118 . The press load δ 2  functions to minimize boot radial deformation. 
         [0046]    Lower slope region  134  transitions to a boot clamping portion  143 , as shown in  FIG. 10B . The boot clamping portion  143  comprises three portions: L 3  (as shown in  FIG. 10A ), L 41 , and L 42 . L 3  comprises a planar portion  144  on an inside surface  146  of the boot  136 . A press load δ 1  is applied to L 3  so that L 3  is located in contact with the sleeve  98 . The press load δ 1  also minimizes the effect, if any, of an inside corner  148  of a boot seat groove  150  that can function like a hinge on the boot  136  to lift it away from the sleeve  98 . A clamp  151  is located in the boot seat groove  150 . 
         [0047]    As seen in  FIG. 10 , the upper slope portion, the concave region and the lower slope region form a C-shape. As a result, the upper slope region is radially above the lower slope region and/or the boot clamping portion. Additionally, a portion of the boot clamping portion extends axially beyond the upper slope region. More particularly, the boot seat groove extends axially beyond the upper slope region. 
         [0048]    A first angled transition  152  in the boot  136  separates L 3  from L 41  and L 42 . The first angled transition  152  has a complementary shape to a first angled transition  154  in an outer surface  156  of the sleeve  98 . The first angled transition extends into the sleeve  98  at a radial angle. The first angled transition  154  in the sleeve  98  leads to a sleeve groove  158 . The sleeve groove  158  is planar. A second angled transition  160  extends from the sleeve groove  158 . The second angled transition  160  extends into the sleeve  98  at a radial angle. 
         [0049]    L 41  and L 42  are coplanar surfaces with one another on the inside surface  146  of the boot  136 . L 41  is designed to be longer than L 42 ; the two lengths being separated by line Y-Y which defines a centerline of the boot seat groove  150  and the clamp  151 . It is preferred that L 41  is longer than L 42  to reduce or prevent region  162  from being lifted and tilted by the above-mentioned corner  148 . Preferably, the thickness of the region  162  is gradually reduced from the general range of thicknesses in the region of T 35  to the general range of thicknesses in the region of T 36  along L 3 . The reduction in thickness also reduces or prevents the region  162  from being lifted and tilted by the corner  148 . A second angled transition  164  in the boot  136 , which is complementary to transition  160 , connects L 42  with a boot end portion  166 . 
         [0050]    L 41  and L 42  are parallel to the sleeve groove  158  and L 41  and L 42  are equal length compared with sleeve groove  158 . And, upon application of a clamping force by the clamp  151 , L 41  and L 42  come into contact with the sleeve groove  158 . Similarly, the first and second angled transitions  152 ,  164  in the boot  136  come into contact with the first and second angled transitions  154 ,  160  in the sleeve  98  upon application of the clamping force. 
         [0051]    Turning now to  FIG. 11 , a second embodiment of a boot system  168  for the direct pinion joint  84  is depicted. The components of the joint  84  and the components of the boot system  168  are the same as those depicted in the first embodiment, except as follows. 
         [0052]    In  FIG. 11 , the straight portion  124  is oriented parallel to a joint center line X-X to improve manufacturability of the boot can  120  and the crimp head  168  in the can  120  by controlling the boot can inner diameter Db 1 . 
         [0053]    Further, the straight portion  124  does not abruptly terminate as in the first embodiment. Instead, a radiused end portion  172  that extends radially inward from the boot  136  is used. 
         [0054]      FIGS. 12 and 12A  depict a third embodiment of a boot system  174  for the direct pinion mount joint  84 . The components of the joint  84  and the components of the boot system  174  are the same as those depicted in the first embodiment, except as follows. 
         [0055]    A boot  176  in  FIGS. 12 and 12A  has a semi-half rectangular cross section that has a thickness that gradually and smoothly decreases from an upper slope region  178  through a concave region  180  down to a lower slope region  182 . Put another way, the thickness T 41  of the upper slope region  178  is greater than the thickness T 42  of the concave region  180 , which is greater than the thickness T 43  of the lower slope region  182 . Additionally, the boot  176  has a straight portion L 8  between the upper slope region  178  and the lower slope region  182 . The straight portion L 8  may be on one or both sides of the boot  176 . While  FIGS. 12 and 12A  depict L 8  as having one length, other lengths are permissible. The straight portion L 8  is designed to maintain grease pressure in the joint  84 . The straight portion may have a thickness T 42  that is substantially constant in order to maintain the grease pressure. 
         [0056]    FIGS.  13  and  14 A- 14 C depict a fourth embodiment of a boot system  184  for the direct pinion mount joint  84 . The components of the joint  84  and the components of the boot system  184  as those depicted in the first embodiment, except as follows: 
         [0057]    In this embodiment, the boot can crimp head  118  depicted and described in the previous embodiments is removed from the boot can  186 . The boot can  186  has the second end portion  114  with an angled, planar portion  116 . The boot can angled, planar portion  116  terminates in a radiused, radially outward extending end  188 . 
         [0058]    The boot can angled, planar portion  116  extends for a length L 7 . An inner surface  190  of the boot  192  is directly bonded or vulcanized to an inner surface  194  of the boot can  186  along the boot can angled, planar portion  116  at least partially along L 7 . 
         [0059]    The boot can  186  and boot  192  attachment depicted in  FIG. 14  provides additional space to increase joint angle capability compared with the first embodiment since the boot head crimp is removed. Additionally, the embodiment depicted in FIGS.  13  and  14 A- 14 C helps simplify the manufacturing process since a boot can crimping step is not required. 
         [0060]    With continued reference to  FIGS. 14A-14C , a boot lower portion  195  may be directly bonded or vulcanized to the sleeve  98  along lengths L 6  and L 61 . A step  196  may be provided between L 6  and L 61  so that a radial height difference H results. The bond or vulcanization of the boot lower portion  195  to the sleeve  98  prevents the boot  192  from being lifted and/or tilted by the inside corner  148 , so that a boot clamp is not required. The step  196  provides increased surface area to connect the boot  192  and the sleeve  98 . The step  196  also provides a stop against which the boot  192  rests to prevent its movement and lock it in place. 
         [0061]    Except as described herein, the boot  192  has the same profile, parts and thicknesses for the upper slope region, the concave region and the lower slope region described in  FIG. 10 . This design reduces boot radial deformation, such as boot folding and self-contact, caused by high grease pressure. 
         [0062]      FIG. 15  depicts a sixth embodiment of a boot system  198  for the direct pinion mount joint  84 . The components of the joint  84  and the components of the boot system  198  are the same as those depicted in the fourth embodiment, except as follows: 
         [0063]    A groove  200  is located in the outer surface  156  of the sleeve  98 . The groove  200  extends continuously circumferentially about the outer surface  156  of the sleeve  98  at the same sleeve axial location. In the depicted embodiment, the groove  200  has a rectangular cross-section, but other shapes are permissible. The groove  200  is located axially adjacent L 6 . The groove  200  has a length L 61 , which is less than L 6 . The groove  200  has a depth H, which preferably is the same height H as the step in  FIG. 14 . 
         [0064]    A boot lower portion  202  terminates in a rib  204 . The rib  204  preferably extends continuously circumferentially radially inward about an inside surface  206  of the boot lower portion  202 . The rib  204  has a complementary shape to the groove  200  and also has height H. In this embodiment, the rib  204  has a rectangular cross-section, but others are permissible. 
         [0065]    The groove  200  and rib  204  provide increased surface area to connect the boot  208  and the sleeve  98 . The groove  200  and rib  204  also function as a stop to prevent movement of the boot  208  and lock it in place. 
         [0066]      FIG. 16  depicts a seventh embodiment of a boot system  210  for the direct pinion mount joint  84 . The components of the joint  84  and the components of the boot system  210  are the same as those depicted in the fourth embodiment, except as follows. 
         [0067]    A groove  212  is located in the boot can angled, planar portion  116 . Preferably, the groove  212  is located at a mid-point between the ends of the angled, planar portion  116  but it may be located at any point between the ends. 
         [0068]    The groove  212  creates a concave surface in an upper surface  214  of the boot can  186  and a corresponding convex surface in a lower surface  216  of the boot can  186 . The groove  212  preferably has the same depth as the radial height H depicted and described in  FIG. 14  of the fourth embodiment. 
         [0069]    As in the fourth embodiment, the inner surface  190  of the boot  192  is directly bonded or vulcanized to the boot can angled, planar portion  116  along the lower surface  216  of the boot can  110  to provide the same advantage. The boot lower portion  194  is similarly attached to the sleeve  54 . The boot  192  has the same thickness as described above for the fourth embodiment. 
         [0070]    The groove  212  provides increased surface area to connect the boot  192  and the boot can  186 . The step  196  also provides a stop against which the boot  192  rests to prevent its movement and lock it in place. 
         [0071]      FIGS. 17 and 17A  depict a seventh embodiment of a boot system  218  utilizing the same components of the joint  84  with some of the boot system components from  FIGS. 9-10  and  FIG. 13 . 
         [0072]    The boot can  186  has the second end portion  114  with the angled, planar portion  116 . The boot can angled, planar portion  116  terminates in the radiused, radially outward extending end  188 , as shown in the embodiment depicted in  FIG. 13 . 
         [0073]    The boot can angled, planar portion  116  extends for length L 7 . The inner surface  190  of the boot  192  is directly bonded or vulcanized to the boot can angled, planar portion  116  at least partially along L 7 . 
         [0074]    The boot can  186  and the above-described method of attaching the boot  192  provides additional space to increase joint angle capability compared with the first embodiment since the boot head crimp is removed. Additionally, this design helps simplify the manufacturing process since a boot can crimping step is not required. 
         [0075]      FIG. 17  shows a lower slope region  134  transitioning to the boot clamping portion  143  as described and depicted in  FIG. 10 . The boot clamping portion  143  comprises three portions: L 3 , L 41 , and L 42 . L 3  is depicted in  FIG. 17A . L 3  comprises the planar portion  144  on the inside surface  146  of the boot  220 . A press load δ 1  is applied to L 3  so that L 3  is located in contact with the sleeve  98 . The press load δ 1  also minimizes the effect, if any, of the inside corner  148  of the boot seat groove  150  that functions like a hinge. 
         [0076]    The first angled transition  152  separates L 3  from L 41  and L 42 . The first angled transition  152  has a complementary shape to the first angled transition  154  in the outer surface  156  of the sleeve  98 . The first angled transition  154  in the sleeve  98  leads to a sleeve groove  158 . A second angled transition  160  extends from the sleeve groove  158 . 
         [0077]    L 41  and L 42  are coplanar surfaces with one another on the inside surface  146  of the boot  220 . L 41  is designed to be longer than L 42 ; the two lengths being divided by line Y-Y which defines a centerline of the sleeve groove  158 . It is preferred that L 41  is longer than L 42  to help prevent region  146  from being lifted and tilted by the above-mentioned hinge. Preferably, the thickness of the region  146  is reduced from T 35  to T 36  along L 3 . This is designed to also prevent the region  146  from being lifted and tilted by the hinge. A second angled transition  164  connects with the boot end portion  166 . 
         [0078]    L 41  and L 42  are parallel to the sleeve groove  158 . And, upon application of a clamping force, L 41  and L 42  come into contact with the sleeve groove  158 . Similarly, the first and second angled transitions  152 ,  164  in the boot  220  come into contact with the first and second angled transitions  154 ,  160  in the sleeve  98  upon application of the clamping force. 
         [0079]      FIG. 18  depicts an eighth embodiment of a boot system  222  utilizing the same components of the joint  84  with some of the boot system components from  FIGS. 9-10  and  FIG. 14 . 
         [0080]    As seen in  FIG. 18 , the boot can  110  has a first end portion  112  connected to the outer race  88  and a second end portion  114  that is cantilevered over the joint  84 . More particularly, the second end portion  114  is cantilevered over a portion of the sleeve  98 . 
         [0081]    The second end portion  114  comprises the angled, planar portion  116  and the boot can crimp head  118  at the end of the angled, planar portion  116 . The boot can crimp head  118  first extends radially outward from the angled, planar portion  116  before it curves around on itself to create the semi-hemispherical hollow portion  120 . One end  122  of the straight portion  124  of the can  110  connects with the semi-hemispherical hollow portion  120 . The boot can  110  terminates at the other end of the straight portion  124 . The straight portion  124  is located radially inward from the angled, planar portion  116 . The gap  128  separates the angled planar portion  116  from the straight portion  124 . 
         [0082]    The boot lower portion  194  is attached to the sleeve  98  such as via a direct bond or vulcanization. The step  196  provides increased surface area to connect the boot  224  and the sleeve  98  and it provides a stop against which the boot  224  rests to prevent its movement and lock it in place. 
         [0083]      FIGS. 19 and 19A  depicts a ninth embodiment of a boot system  226  utilizing the same components of the joint  84  with some of the boot system components from  FIGS. 12 and 13 . 
         [0084]    The boot can  186  has the second end portion  114  with an angled, planar portion  116 . The boot can angled, planar portion  116  terminates in a radiused, radially outward extending end  188 . 
         [0085]    The boot can angled, planar portion  116  extends for a length L 7 . The inner surface  190  of the boot  228  is directly bonded or vulcanized to the boot can angled, planar portion  116  at least partially along L 7 . 
         [0086]    The boot  228  as depicted in  FIGS. 19 and 19A  has a semi-half rectangular cross section that has a thickness that gradually and smoothly decreases from the upper slope region  130  through the concave region  132  down the lower slope region  134 . Put another way, the thickness T 31  of the upper slope region  130  is greater than the thickness T 32  of the concave region  132 , which is greater than the thickness T 33  of the lower slope region  134 . Additionally, the boot has the straight portion L 8  between the upper slope region  130  and the lower slope region  134 . The straight portion L 8  is designed to maintain grease pressure in the joint  84 . Grease pressure is maintained since the boot thickness  229  along L 8  is substantially constant. 
         [0087]    With continued reference to  FIG. 19 , the boot lower portion  194  may be directly bonded or vulcanized to the sleeve  98  along lengths L 6  and L 61 . The step  196  may be provided between L 6  and L 61  so that a radial height difference H results. The bond or vulcanization of the boot lower portion  194  to the sleeve  98  prevents the boot  228  from being lifted and/or tilted by the inside corner  148 , so that no boot clamp is required. The step  196  provides increased surface area to connect the boot  228  and the sleeve  98 . The step  198  also provides a stop against which the boot rests to prevent its movement and lock it in place. 
         [0088]    In addition to the various embodiments described above, other embodiments are also permissible wherein any of the boot system components described above may be combined with one another. 
         [0089]    In accordance with the provisions of the patent statutes, the present invention has been described in what is considered to represent its preferred embodiments. However, it should be noted that the invention can be practiced otherwise than as specifically illustrated and described without departing from its spirit or scope.