Abstract:
In accordance with an aspect of the present disclosure, a vehicle suspension includes an upper member, a lower member, a spring, a jounce bumper, and a striker. The lower member is configured to pivot relative to the upper member. The spring is configured to bias the lower member away from the upper member. The jounce bumper is fixedly coupled to one of the upper and lower members. The striker is fixedly coupled to the other one of the upper and lower members. The striker has a striker surface configured to contact the jounce bumper when the lower member is pivoted to compress the spring greater than a predetermined amount. The striker surface is convex toward the jounce bumper.

Description:
FIELD 
     The present disclosure relates to a vehicle suspension with a jounce bumper and striker. 
     BACKGROUND 
     This section provides background information related to the present disclosure and is not necessarily prior art. 
     Vehicles typically include front and rear suspension components to improve ride and handling of the vehicle. A vehicle suspension system, such as a rear suspension for example, typically includes a primary spring and a shock absorber. The primary spring resiliently supports the vehicle&#39;s chassis and body relative to a wheel of the vehicle. In some applications, the primary spring is a compression style coil spring. The shock absorber is configured to absorb and dampen vibration of the primary spring. 
     Vehicle suspensions typically also include a striker and a secondary spring device that is commonly known as a “jounce bumper” or a “bump-stop”. The striker and jounce bumper are mounted to components of the vehicle body, chassis, or suspension (e.g. a spring link or arm) that are coupled to each other for relative movement. Typically, the striker and jounce bumper pivot relative to each other and are aligned to contact one another at a predetermined pivot angle. The jounce bumper is typically a rubber or resilient polymer material and is positioned to impact the striker before the primary spring bottoms out. The jounce bumper is generally configured to compress against a contact surface of the striker and prevent bottoming out of the primary spring. 
     The contact surface of typical strikers is flat or concave. The pivoting motion of the striker relative to the jounce bumper can create undesirable side loading forces as the jounce bumper compresses against the flat or concave contact surface. These side loading forces can result in the jounce bumper bending instead of compressing throughout the jounce bumper&#39;s designed compression range. 
     SUMMARY 
     This section provides a general summary of the disclosure, and is not a comprehensive disclosure of its full scope or all of its features. 
     In accordance with an aspect of the present disclosure, a vehicle suspension includes an upper member, a lower member, a spring, a jounce bumper, and a striker. The lower member is configured to pivot relative to the upper member. The spring is configured to bias the lower member away from the upper member. The jounce bumper is fixedly coupled to one of the upper and lower members. The striker is fixedly coupled to the other one of the upper and lower members. The striker has a striker surface configured to contact the jounce bumper when the lower member is pivoted to compress the spring greater than a predetermined amount. The striker surface is convex toward the jounce bumper. 
     In accordance with an aspect of the present disclosure, an entire surface area of the striker surface that is configured to contact the jounce bumper is convex. 
     In accordance with an aspect of the present disclosure, the suspension further includes a chassis. The lower member has opposing ends including a chassis attachment end and a hub attachment end. The chassis attachment end is pivotably coupled to the chassis. The hub attachment end is configured to be coupled to a wheel hub. The striker includes a base mounted to the lower member. The striker surface slopes toward the base with increased distance from the chassis attachment end. 
     In accordance with an aspect of the present disclosure, the lower member extends in an outboard direction from the chassis attachment end to the hub attachment end. 
     In accordance with an aspect of the present disclosure, the spring is a coil spring coiled about the jounce bumper and the striker. 
     In accordance with an aspect of the present disclosure, the lower member is movable between a first position wherein the jounce bumper makes initial contact with the striker surface, and a second position wherein the jounce bumper is compressed against the striker surface. The striker surface is curved such that a portion of the striker surface that contacts the jounce bumper remains perpendicular to a central axis of the jounce bumper while the lower member moves between the first and second positions. 
     In accordance with an aspect of the present disclosure, the striker surface is defined by 
     
       
         
           
             θ 
             = 
             
               
                 ( 
                 
                   
                     
                       
                         r 
                         2 
                       
                       - 
                       
                         R 
                         2 
                       
                     
                   
                   R 
                 
                 ) 
               
               - 
               
                 
                   
                     tan 
                     
                       - 
                       1 
                     
                   
                   ⁡ 
                   
                     ( 
                     
                       
                         
                           
                             r 
                             2 
                           
                           - 
                           
                             R 
                             2 
                           
                         
                       
                       R 
                     
                     ) 
                   
                 
                 . 
               
             
           
         
       
     
     In accordance with an aspect of the present disclosure, the jounce bumper is fixedly coupled to the upper member and the striker is fixedly coupled to the lower member. 
     In accordance with an aspect of the present disclosure, the jounce bumper is fixedly coupled to the lower member and the striker is fixedly coupled to the upper member. 
     In accordance with an aspect of the present disclosure, a vehicle suspension includes an upper member, a lower member, a spring, a jounce bumper, and a striker. The lower member is configured to pivot between a first position and a second position relative to the upper member. The spring is configured to bias the lower member away from the upper member. The jounce bumper is fixedly coupled to one of the upper and lower members. The striker is fixedly coupled to the other one of the upper and lower members. The striker has a striker surface configured to contact the jounce bumper at an angle that is perpendicular to a central axis of the jounce bumper when the lower member is in the first and second positions. 
     In accordance with an aspect of the present disclosure, the striker surface is convex toward the jounce bumper along an entire surface area of the striker surface that contacts the jounce bumper when the lower member is between the first and second positions. 
     In accordance with an aspect of the present disclosure, the vehicle suspension further includes a chassis. The lower member has opposing ends including a chassis attachment end and a hub attachment end. The chassis attachment end is pivotably coupled to the chassis. The hub attachment end is configured to be coupled to a wheel hub. The striker includes a base mounted to the lower member. The striker surface slopes toward the base with increased distance from the chassis attachment end. 
     In accordance with an aspect of the present disclosure, the lower member extends in an outboard direction from the chassis attachment end to the hub attachment end. 
     In accordance with an aspect of the present disclosure, the spring is a coil spring coiled about the jounce bumper and the striker. 
     In accordance with an aspect of the present disclosure, when the lower member is in the first position the jounce bumper makes initial contact with the striker surface. When the lower member is in the second position the jounce bumper is compressed against the striker surface. 
     In accordance with an aspect of the present disclosure, the striker surface is defined by 
     
       
         
           
             θ 
             = 
             
               
                 ( 
                 
                   
                     
                       
                         r 
                         2 
                       
                       - 
                       
                         R 
                         2 
                       
                     
                   
                   R 
                 
                 ) 
               
               - 
               
                 
                   
                     tan 
                     
                       - 
                       1 
                     
                   
                   ⁡ 
                   
                     ( 
                     
                       
                         
                           
                             r 
                             2 
                           
                           - 
                           
                             R 
                             2 
                           
                         
                       
                       R 
                     
                     ) 
                   
                 
                 . 
               
             
           
         
       
     
     In accordance with an aspect of the present disclosure, the jounce bumper is fixedly coupled to the upper member and the striker is fixedly coupled to the lower member. 
     In accordance with an aspect of the present disclosure, the jounce bumper is fixedly coupled to the lower member and the striker is fixedly coupled to the upper member. 
     Further areas of applicability will become apparent from the description provided herein. The description and specific examples in this summary are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure. 
    
    
     
       DRAWINGS 
       The drawings described herein are for illustrative purposes only of selected embodiments and not all possible implementations, and are not intended to limit the scope of the present disclosure. 
         FIG. 1  is a perspective view of a vehicle suspension in accordance with the present teachings; 
         FIG. 2  is a perspective view of a striker of the vehicle suspension of  FIG. 1 ; 
         FIG. 3  is a different perspective view of the striker of  FIG. 2 ; 
         FIG. 4  is a sectional view of a portion of the vehicle suspension of  FIG. 1  taken along line  4 - 4  as shown in  FIG. 1 , and illustrating the vehicle suspension in a first position; and 
         FIG. 5  is a section view similar to  FIG. 4 , illustrating the vehicle suspension in a second position. 
     
    
    
     Corresponding reference numerals indicate corresponding parts throughout the several views of the drawings. 
     DETAILED DESCRIPTION 
     The following description of the preferred embodiment(s) is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses. 
     The present teachings are directed toward a vehicle suspension configured to reduce side loads between a jounce bumper and a striker of the vehicle suspension. The striker has a contact surface that promotes axial compression of the jounce bumper and reduces side loads on the jounce bumper. 
     With reference to  FIG. 1 , a portion of a vehicle suspension  10  is illustrated. The vehicle suspension  10  generally includes a shock absorber  14 , a spring  18 , a spring link  22 , a striker  26 , an upper spring perch  28  and a jounce bumper  30 . In the example shown, the vehicle suspension  10  also includes a chassis  34 , a hub carrier  38 , a hub  42 , and an upper arm  46 , though other configurations can be used. 
     The chassis  34  is a rigid structure that typically is fixedly coupled to a body (not shown) of the vehicle. The upper arm  46  is a rigid member having a first end  50  and a second end  54  opposite the first end  50 . The first end  50  is pivotably coupled to the chassis  34 , and the second end  54  is pivotably coupled to the hub carrier  38 . The hub carrier  38  is coupled to the hub  42  and supports the hub  42  for rotation relative to the hub carrier  38 . The hub  42  is configured to be fixedly coupled to a wheel (not shown) of the vehicle in a conventional manner (e.g. studs and lug nuts) to permit the wheel to rotate relative to the hub carrier  38  about a rotational axis  58  of the hub  42 . 
     The spring link  22  is a rigid member that has a third end  62 , a fourth end  66  opposite the third end  62 , and a lower spring perch  70  located between the third and fourth ends  62 ,  66 . The third end  62  is pivotably coupled to the chassis  34  at a location that is spaced apart from the first end  50  of the upper arm  46 . The third end  62  is pivotably coupled to the chassis  34  such that the spring link  22  is rotatable relative to the chassis  34  about a first axis  74 . The fourth end  66  is pivotably coupled to the hub carrier  38  at a location that is spaced apart from the second end  54  of the upper arm  46 . 
     With continued reference to  FIG. 1  and additional reference to  FIG. 4 , the lower spring perch  70  is configured to support the spring  18  on the spring link  22 . In the example provided, the lower spring perch  70  includes a pot-shaped cavity  78  defined by the spring link  22 , though other configurations can be used. The cavity  78  includes a bottom wall  82  that is recessed below a top surface  86  of the spring link  22 , and a sidewall  90  that extends between the top surface  86  and the bottom wall  82 . In the example provided, the bottom wall  82  defines a plurality of apertures  94 , though other configurations can be used. 
     In the example provided, the spring  18  is a compression coil spring formed of a metal material, though other configurations can be used. A lower portion of the spring  18  is received in the cavity  78  and is seated generally on the bottom wall  82 . An upper portion of the spring  18 , opposite the lower portion, is seated on the upper spring perch  28 . 
     The upper spring perch  28  is mounted to a structure  96  of the vehicle, which can be a portion of the chassis  34  or the body (not shown) of the vehicle. In the example provided, the upper spring perch  28  includes a plate portion  98  and a cylindrical portion  102 . The plate portion  98  is generally flat and disc-shaped and is mounted to the structure  96 , generally above the lower spring perch  70 . The cylindrical portion  102  is fixedly coupled to the plate portion  98  and is generally cylindrical in shape. The cylindrical portion  102  extends from the plate portion  98  downwards toward the lower spring perch  70 . The upper portion of the spring  18  is seated on the plate portion  98  of the upper spring perch  28  and the coils of the spring  18  extend coaxially about the cylindrical portion  102  toward the lower portion of the spring  18 . 
     The jounce bumper  30  is a generally cylindrical body having a base  106  and a free end  110 . The base  106  is fixedly coupled to the cylindrical portion  102  of the upper spring perch  28 . The jounce bumper  30  extends from the base  106  along a second axis  114 , downward toward the lower spring perch  70  to the free end  110  which is opposite from the base  106 . The jounce bumper  30  is formed of a resilient material, such as rubber or a resilient polymer for example. In the example provided, the jounce bumper  30  defines a plurality of notches that extend circumferentially about the jounce bumper  30  and are positioned between the base  106  and the free end  110 . The plurality of notches  118  are configured to aid in controlled compression and expansion of the jounce bumper  30  along the second axis  114 . In the example provided, the free end  110  has a frustoconical shape with the frustum proximate to the lower spring perch  70 , and the free end  110  defines a conical cavity  122  that is coaxial with the second axis  114 , though other configurations can be used. 
     The shock absorber  14  can be any suitable type of shock absorber, such as a gas-filled or oil-filled piston-cylinder damper for example. The shock absorber  14  is operatively coupled between the hub carrier  38  and a structure  126  of the vehicle which can be a portion of the chassis  34  or body (not shown) of the vehicle. In the example provided, an upper portion of the shock absorber  14  is mounted to the structure  126  of the vehicle for common movement therewith, and a lower portion of the shock absorber  14  is mounted to the hub carrier  38  for movement therewith, though other configurations can be used. In alternative constructions (not specifically shown), the lower portion of the shock absorber  14  is mounted to the spring link  22  or a portion of the upper arm  46  for movement therewith. The shock absorber  14  is configured to dampen oscillation of the hub carrier  38  due to the spring  18 . 
     With additional reference to  FIGS. 2 and 3 , the striker  26  is illustrated in greater detail. The striker  26  is generally coupled to the spring link  22  and configured to strike the jounce bumper  30  when the spring link  22  rotates about the first axis  74  to prevent the spring  18  from bottoming out (e.g. the coils of the spring becoming fully compressed). In an alternative construction (not specifically shown), the jounce bumper  30  is coupled to the spring link  22  and the striker  26  is coupled to the upper spring perch  28 . In the example provided, the striker  26  includes a rim  210 , a body  214 , and a plurality of protrusions  218 , though other configurations can be used. 
     The rim  210  is configured to be received in the cavity  78  and to rest upon the bottom wall  82 . In the example provided, the rim  210  has a thin, circular shape that is coaxial with the lower portion of the spring  18 . In the example provided, the rim  210  defines a bore  222  and a fastener  226  (shown in  FIG. 4 ) is received through the bottom wall  82  and the bore  222  to fixedly couple the striker  26  to the spring link  22 . The protrusions  218  extend from a bottom of the rim  210  and are spaced apart and disposed circumferentially about the rim  210 . Each of the protrusions  218  is received in one of the apertures  94  of the bottom wall  82  to prevent rotation of the striker  26  relative to the spring link  22 . 
     The body  214  is a generally cylindrical shape that extends upward from the rim  210  and has a striker surface  230  that is distal to the rim  210 . The striker surface  230  is generally convex toward the jounce bumper  30 . In the example provided, the striker surface  230  is a two-dimensional surface having a cross-sectional profile (e.g. taken along longitudinal line  234 ), such that any point on the striker surface  230  taken along a transverse line (e.g. one of lines  238  that are perpendicular to longitudinal line  234 ) has the same minimum distance to a plane  240  that is parallel with the rim  210  as any other point on that line. The striker surface  230  can also have a flat area  242  in addition to a convex or curved area  244 . The flat area  242  is parallel to the plane  240  and is located proximate to an inboard side  246  of the striker  26 . The flat area  242  transitions into the curved area  244 . The curved area  244  is curved such that the striker surface  230  is further from the plane  240  at the inboard side  246  of the striker  26  and continuously becomes closer to the plane  240  (in a convex manner relative to the jounce bumper  30 ) as the striker surface  230  progresses to an outboard side  248  of the striker  26 . The exact profile curve of the striker surface  230  is described in greater detail below. In the example provided, the bore  222  in the rim  210  is located at the outboard side  248  of the striker, though other configurations can be used. 
     With additional reference to  FIGS. 4 and 5 , the jounce bumper  30 , the spring link  22 , and the striker  26  are shown in a first position ( FIG. 4 ) and a second position ( FIG. 5 ). In the first position, the free end  110  of the jounce bumper  30  contacts the striker surface  230  at a first location  250 . The first location  250  is a distance from the first axis  74  indicated by a constant value R. In the example provided, the first location  250  has a slope relative to the rim  210  and is located on the second axis  114  such that the jounce bumper  30  is generally centered over the first location  250 . As the spring link  22  rotates in direction  254  about the first axis  74 , the spring link  22  rotates at an angle indicated by variable θ. As the spring link  22  rotates through different angles θ, the jounce bumper  30  compresses against the striker surface  230  and the free end  110  of the jounce bumper  30  contacts the striker surface  230  at different locations that are located a distance from the first axis  74  indicated by a variable r. Thus, r 0  is equal to R. 
     For example, when in the second position, the free end  110  contacts the striker surface  230  at a second location  258  that is different than the first location  250 . In the example provided, the second location  258  has a slope relative to the rim  210  that is different than the slope at the first location  250 . In the example provided, the second location  258  is located on the second axis  114  such that the jounce bumper  30  is generally centered over the second location  258  when in the second position. The second location  258  is a distance r 1  from the first axis  74  and the angle that the spring link  22  and striker  26  have moved relative to the first position is θ 1 . Due to the compression and deformation of the jounce bumper  30 , it is understood that a portion of the free end  110  may continue to contact the striker surface  230  at the first location  250  while the jounce bumper  30  engages the second location  258 . 
     In the example provided, the relationship between the angle θ of the spring link  22  and the distance r from the first axis  74  to the location on the striker surface  230  that contacts the jounce bumper  30  is mathematically expressed in the equation below. 
     
       
         
           
             θ 
             = 
             
               
                 ( 
                 
                   
                     
                       
                         r 
                         2 
                       
                       - 
                       
                         R 
                         2 
                       
                     
                   
                   R 
                 
                 ) 
               
               - 
               
                 
                   tan 
                   
                     - 
                     1 
                   
                 
                 ⁡ 
                 
                   ( 
                   
                     
                       
                         
                           r 
                           2 
                         
                         - 
                         
                           R 
                           2 
                         
                       
                     
                     R 
                   
                   ) 
                 
               
             
           
         
       
     
     In the equation above, variable θ represents the angular position of the spring link  22  and striker  26 , constant R represents the distance from the first axis  74  to the initial central point of contact between the striker  26  and the jounce bumper  30 , and variable r represents the distance from the first axis  74  to the central point of contact between the striker  26  and the jounce bumper  30  at a given angular position θ, as described above. 
     In operation, when the vehicle traverses over terrain that causes the hub  42  to move up and down (i.e. the spring link  22  rotates about the first axis  74 ), the spring  18  compresses and expands accordingly and the jounce bumper  30  can contact the striker  26  to prevent the spring  18  from bottoming out. The striker surface  230  profile described above ensures that the striker surface  230  impacts the jounce bumper  30  at a perpendicular angle, such that the impact force of the striker  26  on the jounce bumper  30  acts along the second axis  114 . The profile of the striker surface  230  thus eliminates or minimizes forces between the striker  26  and the jounce bumper  30  that would act transverse to the second axis  114 . In other words, the profile of the striker surface  230  ensures that the jounce bumper  30  compresses along the second axis  114  instead of buckling or bending transverse to the second axis  114 . 
     The descriptions above are merely exemplary in nature and, thus, variations that do not depart from the gist of the present disclosure are intended to be within the scope of the invention. Such variations are not to be regarded as a departure from the spirit and scope of the invention.