Abstract:
A magnetic system for controlling the operating mode of an overrunning coupling assembly is provided. The system includes a ferromagnetic or magnetic element received within a pocket in an uncoupling position and is movable outwardly from the pocket to a coupling position. The element controls the operating mode of the coupling assembly. An armature is connected to the element to move the element between the coupling and uncoupling positions. A magnetic field sensor is disposed adjacent and stationary with respect to the element for sensing magnetic flux to produce an output signal which is based on the position of the element. A variable magnetic field is generated in response to movement of the element between the coupling and uncoupling positions.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of provisional patent application Ser. No. 61/941,741 filed Feb. 19, 2014 and Ser. No. 61/870,434 filed Aug. 27, 2013. This application is a continuation-in-part of U.S. patent application Ser. No. 13/992,785 filed Jun. 10, 2013 which is a 371 of PCT/US2011/036634 filed May 16, 2011 which, in turn, claims the benefit of provisional patent application Ser. No. 61/421,856 filed Dec. 10, 2010. 
    
    
     OVERVIEW 
     Coupling assemblies such as clutches are used in a wide variety of applications to selectively couple power from a first rotatable driving member, such as a driving disk or plate, to a second, independently rotatable driven member, such as a driven disk or plate. In one known variety of clutches, commonly referred to as “one-way” or “overrunning” clutches, the clutch engages to mechanically couple the driving member to the driven member only when the driving member rotates in a first direction relative to the driven member. Once so engaged, the clutch will release or decouple the driven member from the driving member only when the driving member rotates in a second, opposite direction relative to the driven member. Further, the clutch otherwise permits the driving member to freely rotate in the second direction relative to the driven member. Such “freewheeling” of the driving member in the second direction relative to the driven member is also known as the “overrunning” condition. 
     One type of one-way clutch includes coaxial driving and driven plates having generally planar clutch faces in closely spaced, juxtaposed relationship. A plurality of recesses or pockets is formed in the face of the driving plate at angularly spaced locations about the axis, and a strut or pawl is disposed in each of the pockets. Multiple recesses or notches are formed in the face of the driven plate and are engageable with one or more of the struts when the driving plate is rotating in a first direction. When the driving plate rotates in a second direction opposite the first direction, the struts disengage the notches, thereby allowing freewheeling motion of the driving plate with respect to the driven plate. 
     When the driving plate reverses direction from the second direction to the first direction, the driving plate typically rotates relative to the driven plate until the clutch engages. As the amount of relative rotation increases, the potential for an engagement noise also increases. 
     Controllable or selectable one-way clutches (i.e., OWCs) are a departure from traditional one-way clutch designs. Selectable OWCs add a second set of locking members in combination with a slide plate. The additional set of locking members plus the slide plate adds multiple functions to the OWC. Depending on the needs of the design, controllable OWCs are capable of producing a mechanical connection between rotating or stationary shafts in one or both directions. Also, depending on the design, OWCs are capable of overrunning in one or both directions. A controllable OWC contains an externally controlled selection or control mechanism. Movement of this selection mechanism can be between two or more positions which correspond to different operating modes. 
     U.S. Pat. No. 5,927,455 discloses a bi-directional overrunning pawl-type clutch, U.S. Pat. No. 6,244,965 discloses a planar overrunning coupling, and U.S. Pat. No. 6,290,044 discloses a selectable one-way clutch assembly for use in an automatic transmission. U.S. Pat. Nos. 7,258,214 and 7,344,010 disclose overrunning coupling assemblies, and U.S. Pat. No. 7,484,605 discloses an overrunning radial coupling assembly or clutch. 
     A properly designed controllable OWC can have near-zero parasitic losses in the “off” state. It can also be activated by electro-mechanics and does not have either the complexity or parasitic losses of a hydraulic pump and valves. 
     In a powershift transmission, tip-in clunk is one of most difficult challenges due to absence of a torque converter. When the driver tips-in, i.e., depresses the accelerator pedal following a coast condition, gear shift harshness and noise, called clunk, are heard and felt in the passenger compartment due to the mechanical linkage, without a fluid coupling, between the engine and powershift transmission input. Tip-in clunk is especially acute in a parking-lot maneuver, in which a vehicle coasting at low speed is then accelerated in order to maneuver into a parking space. 
     In order to achieve good shift quality and to eliminate tip-in clunk, a powershift transmission should employ a control strategy that is different from that of a conventional automatic transmission. The control system should address the unique operating characteristics of a powershift transmission and include remedial steps to avoid the objectionable harshness yet not interfere with driver expectations and performance requirements of the powershift transmission. There is a need to eliminate shift harshness and noise associated with tip-in clunk in a powershift transmission. 
     For purposes of this disclosure, the term “coupling” should be interpreted to include clutches or brakes wherein one of the plates is drivably connected to a torque delivery element of a transmission and the other plate is drivably connected to another torque delivery element or is anchored and held stationary with respect to a transmission housing. The terms “coupling”, “clutch” and “brake” may be used interchangeably. 
     A pocket plate may be provided with angularly disposed recesses or pockets about the axis of the one-way clutch. The pockets are formed in the planar surface of the pocket plate. Each pocket receives a torque transmitting strut, one end of which engages an anchor point in a pocket of the pocket plate. An opposite edge of the strut, which may hereafter be referred to as an active edge, is movable from a position within the pocket to a position in which the active edge extends outwardly from the planar surface of the pocket plate. The struts may be biased away from the pocket plate by individual springs. 
     A notch plate may be formed with a plurality of recesses or notches located approximately on the radius of the pockets of the pocket plate. The notches are formed in the planar surface of the notch plate. 
     Another example of an overrunning planar clutch is disclosed in U.S. Pat. No. 5,597,057. 
     Some U.S. patents related to the present invention include: U.S. Pat. Nos. 5,052,534; 5,070,978; 5,449,057; 5,678,668; 5,806,643; 5,871,071; 5,918,715; 5,964,331; 5,979,627; 6,065,576; 6,116,394; 6,125,980; 6,129,190; 6,186,299; 6,193,038; 6,386,349; 6,481,551; 6,505,721; 6,571,926; 6,814,201; 7,153,228; 7,275,628; 8,051,959; 8,196,724; and 8,286,772. 
     Yet still other related U.S. patents include: U.S. Pat. Nos. 4,200,002; 5,954,174; and 7,025,188. 
     U.S. Pat. No. 6,854,577 discloses a sound-dampened, one-way clutch including a plastic/steel pair of struts to dampen engagement clunk. The plastic strut is slightly longer than the steel strut. This pattern can be doubled to dual engaging. This approach has had some success. However, the dampening function stopped when the plastic parts became exposed to hot oil over a period of time. 
     Metal injection molding (MIM) is a metalworking process where finely-powdered metal is mixed with a measured amount of binder material to comprise a ‘feedstock’ capable of being handled by plastic processing equipment through a process known as injection mold forming. The molding process allows complex parts to be shaped in a single operation and in high volume. End products are commonly component items used in various industries and applications. The nature of MIM feedstock flow is defined by a science called rheology. Current equipment capability requires processing to stay limited to products that can be molded using typical volumes of 100 grams or less per “shot” into the mold. Rheology does allow this “shot” to be distributed into multiple cavities, thus becoming cost-effective for small, intricate, high-volume products which would otherwise be quite expensive to produce by alternate or classic methods. The variety of metals capable of implementation within MIM feedstock are referred to as powder metallurgy, and these contain the same alloying constituents found in industry standards for common and exotic metal applications. Subsequent conditioning operations are performed on the molded shape, where the binder material is removed and the metal particles are coalesced into the desired state for the metal alloy. 
     Other U.S. patent documents related to at least one aspect of the present invention includes U.S. Pat. Nos. 8,491,440; 8,491,439; 8,272,488; 8,187,141; 8,079,453; 8,007,396; 7,942,781; 7,690,492; 7,661,518; 7,455,157; 7,455,156; 7,451,862; 7,448,481; 7,383,930; 7,223,198; 7,100,756; and 6,290,044; and U.S. published application Nos. 2013/0062151; 2012/0152683; 2012/0149518; 2012/0152687; 2012/0145505; 2011/0233026; 2010/0105515; 2010/0230226; 2009/0233755; 2009/0062058; 2008/0110715; 2008/0188338; 2008/0185253; 2006/0185957; and 2006/0021838. 
     As used herein, the term “sensor” is used to describe a circuit or assembly that includes a sensing element and other components. In particular, as used herein, the term “magnetic field sensor” is used to describe a circuit or assembly that includes a magnetic field sensing element and electronics coupled to the magnetic field sensing element. 
     As used herein, the term “magnetic field sensing element” is used to describe a variety of electronic elements that can sense a magnetic field. The magnetic field sensing elements can be, but are not limited to, Hall effect elements, magnetoresistance elements, or magnetotransistors. As is known, there are different types of Hall effect elements, for example, a planar Hall element, a vertical Hall element, and a circular vertical Hall (CVH) element. As is also known, there are different types of magnetoresistance elements, for example, a giant magnetoresistance (GMC) element, an anisotropic magnetoresistance element (AMR), a tunneling magnetoresistance (TMR) element, an Indium antimonide (InSb) sensor, and a magnetic tunnel junction (MTJ). 
     As is known, some of the above-described magnetic field sensing elements tend to have an axis of maximum sensitivity parallel to a substrate that supports the magnetic field sensing element, and others of the above-described magnetic field sensing elements tend to have an axis of maximum sensitivity perpendicular to a substrate that supports the magnetic field sensing element. In particular, planar Hall elements tend to have axes of sensitivity perpendicular to a substrate, while magnetoresistance elements and vertical Hall elements (including circular vertical Hall (CVH) sensing element) tend to have axes of sensitivity parallel to a substrate. 
     Magnetic field sensors are used in a variety of applications, including, but not limited to, an angle sensor that senses an angle of a direction of a magnetic field, a current sensor that senses a magnetic field generated by a current carried by a current-carrying conductor, a magnetic switch that senses the proximity of a ferromagnetic object, a rotation detector that senses passing ferromagnetic articles, for example, magnetic domains of a ring magnet, and a magnetic field sensor that senses a magnetic field density of a magnetic field. 
     Modern automotive vehicles employ an engine transmission system having gears of different sizes to transfer power produced by the vehicle&#39;s engine to the vehicle&#39;s wheels based on the speed at which the vehicle is traveling. The engine transmission system typically includes a clutch mechanism which may engage and disengage these gears. The clutch mechanism may be operated manually by the vehicle&#39;s driver, or automatically by the vehicle itself based on the speed at which the driver wishes to operate the vehicle. 
     In automatic transmission vehicles, a need arises for the vehicle to sense the position of the clutch for smooth, effective shifts between gears in the transmission and for overall effective transmission control. Therefore, a clutch-position sensing component for sensing the linear position of the clutch may be used by automatic transmission vehicles to facilitate gear shifting and transmission control. 
     Current clutch-position sensing components utilize magnetic sensors. One advantage to using magnetic sensors is that the sensor need not be in physical contact with the object being sensed, thereby avoiding mechanical wear between the sensor and the object. However, actual linear clutch measurement accuracy may be compromised when the sensor is not in physical contact with the sensed object because of a necessary gap or tolerance that exists between the sensor and the object. Moreover, current sensing systems addressing this problem use coils and certain application-specific integrated circuits which are relatively expensive. 
     U.S. Pat. No. 8,324,890 discloses a transmission clutch position sensor which includes two Hall sensors located at opposite ends of a flux concentrator outside the casing of the transmission to sense a magnetic field generated by a magnet attached to the clutch piston. To reduce sensitivity to magnet-to-sensor gap tolerances, a ratio of the voltage of one Hall sensor to the sum of the voltages from both Hall sensors is used to correlate to the piston and, hence, clutch position. 
     SUMMARY OF EXAMPLE EMBODIMENTS 
     An object of at least one embodiment of the present invention is to provide a magnetic control system for controlling the operating mode of an overrunning coupling assembly and an overrunning coupling and magnetic control assembly having such a system. 
     In carrying out the above object and other objects of at least one embodiment of the present invention, a magnetic system for controlling the operating mode of an overrunning coupling assembly is provided. The assembly includes a coupling member having a first coupling face and a coupling subassembly having a second coupling face with a pocket defining a load-bearing shoulder. The coupling faces are in close-spaced opposition with one another. At least one of the coupling member and the coupling subassembly is mounted for rotation about a rotary axis. The system includes a ferromagnetic or magnetic element received within the pocket in an uncoupling position and movable outwardly from the pocket to a coupling position characterized by abutting engagement of the element with the load-bearing shoulder. The element controls the operating mode of the coupling assembly. An electromagnetic source includes at least one excitation coil. A reciprocating armature is arranged concentrically relative to the at least one excitation coil and is axially movable when the at least one excitation coil is supplied with current. The armature is connected to the element to move the element between the coupling and uncoupling positions. A magnetic field sensor is disposed adjacent and stationary with respect to the element for sensing magnetic flux to produce an output signal which is based on the position of the element. A variable magnetic field is generated in response to movement of the element between the coupling and uncoupling positions. 
     The sensor may include a magnetic field sensing element. 
     The sensor may be back-biased wherein the element is a ferromagnetic element. 
     The element may be a locking element which controls the operating mode of the coupling assembly. 
     The locking element may be an injection molded strut. 
     The system may further include a return biasing member to urge the armature to a return position which corresponds to the uncoupling position of the element. 
     The coupling faces may be oriented to face axially. 
     The pocket may have a T-shape. 
     The element may include at least one projecting leg portion which provides an attachment location for a leading end of the armature. 
     Each leg portion may have an aperture, wherein the system may further include a pivot pin received within each aperture to allow rotational movement of the element in response to reciprocating movement of the armature and wherein the leading end of the armature may be connected to the element via the pivot pin. 
     Each aperture may be an oblong aperture to receive the pivot pin to allow both rotation and translational movement of the element in response to reciprocating movement of the armature. 
     The coupling assembly may be a clutch assembly and the coupling faces may be clutch faces. 
     Further in carrying out the above object and other objects of at least one embodiment of the present invention, an overrunning coupling and magnetic control assembly is provided. The assembly includes a coupling member having a first coupling face and a coupling subassembly having a second coupling face with a pocket defining a load-bearing shoulder. The coupling faces are in close-spaced opposition with one another. At least one of the coupling member and the coupling subassembly is mounted for rotation about a rotary axis. A ferromagnetic or magnetic element is received within the pocket in an uncoupling position and is movable outwardly from the pocket to a coupling position characterized by abutting engagement of the element with the load-bearing shoulder. The element controls the operating mode of the coupling assembly. An electromagnetic source includes at least one excitation coil. A reciprocating armature is arranged concentrically relative to the at least one excitation coil and is axially movable when the at least one excitation coil is supplied with current. The armature is connected to the element to move the element between the coupling and uncoupling positions. A magnetic field sensor is disposed adjacent and stationary with respect to the element for sensing magnetic flux to produce an output signal which is based on the position of the element. A variable magnetic field is generated in response to movement of the element between the coupling and uncoupling positions. 
     The sensor may include a magnetic field sensing element. 
     The sensor may be back-biased wherein the element is a ferromagnetic element. 
     The element may be a locking element such as an injection molded strut. 
     The assembly may further include a return biasing member to urge the armature to a return position which corresponds to the uncoupling position of the element. 
     The coupling faces may be oriented to face axially. 
     The pocket may have a T-shape. 
     The element may include at least one projecting leg portion which provides an attachment location for a leading end of the armature. 
     Each leg portion may have an aperture. The assembly may further include a pivot pin received within each aperture to allow rotational movement of the element in response to reciprocating movement of the armature. The leading end of the armature may be connected to the element via the pivot pin. 
     Each aperture may be an oblong aperture to receive the pivot pin to allow both rotation and translational movement of the element in response to reciprocating movement of the armature. 
     The coupling member may be a clutch member and the coupling faces may be clutch faces. 
     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. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an exploded perspective view of a magnetic control system of at least one embodiment of the present invention taken from the bottom of the system; 
         FIG. 2  is an exploded perspective view of the system taken from the top of the system; and 
         FIG. 3  is a view, partially broken away and in cross section, of an overrunning coupling and magnetic control assembly of at least one embodiment of the present invention utilizing the system. 
     
    
    
     DETAILED DESCRIPTION 
     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. 
     Referring now to  FIG. 3 , there is illustrated a planar, controllable coupling assembly, generally indicated at  11 . The assembly  11  includes a first coupling member, generally indicated at  10 , a notch plate or member, generally indicated at  12 , and an electromechanical apparatus, generally indicated at  15 . The coupling assembly  11  may be a ratcheting, one-way clutch assembly. The second member  12  includes a second coupling face  16  in closed-spaced opposition with an outer coupling face  14  of a housing part  13  of the apparatus  15  when the members  10  and  12  are assembled and held together by a locking or snap ring  18 . At least one of the members  10  and  12  is mounted for rotation about a common rotational axis. 
     The outer coupling face  14  of the housing part  13  has a single, T-shaped recess or pocket  22 , as best shown in  FIG. 2 . The recess  22  defines a load-bearing first shoulder  24 . The second coupling face  16  of the notch plate  12  has a plurality of recesses or notches (not shown but well known in the art). Each notch of the notches defines a load-bearing second shoulder. 
     Referring to  FIGS. 1-3 , the electromechanical apparatus  15  may include a locking strut or element, generally included at  26 , disposed between the coupling faces  14  and  16  of the housing part  13  and the member  12 , respectively, when the members  10  and  12  are assembled and held together. 
     The element  26  may comprise a ferromagnetic locking element or strut movable between first and second positions. The first position (phantom lines in  FIG. 3 ) is characterized by abutting engagement of the locking element  26  with a load-bearing shoulder (not shown) of the member  12  and the shoulder  24  of the pocket  22  formed in an end wall  28  of the housing part  13 . The second position (solid lines in  FIG. 3 ) is characterized by non-abutting engagement of the locking element  26  with a load-bearing shoulder of at least one of the member  12  and the end wall  28 . 
     The electromechanical apparatus  15  includes the housing part  13  which has a closed axial end including the end wall  28 . The end wall  28  has the outer coupling face  14  with the single pocket  22  which defines the load-bearing shoulder  24  which is in communication with an inner face  29  of the end wall  28 . The housing part  13  may be a metal (such as aluminum) injection molded (MIM) part. 
     The apparatus  15  also includes an electromagnetic source, generally indicated at  31 , including at least one excitation coil  33  which is at least partially surrounded by a skirt of the housing part  13 . 
     The element or strut  26  is shown as being received within the pocket  22  in its refracted, uncoupling position in  FIG. 3 . The strut  26  is movable outwardly from the pocket  22  to an extended, coupling position (phantom lines in  FIG. 3 ) characterized by abutting engagement of the strut  26  with a load-bearing shoulder of the notch plate  12  and the shoulder  24 . 
     The apparatus  15  also includes a reciprocating armature, generally indicated at  35 , arranged concentrically relative to the at least one excitation coil  33  and is axially movable when the at least one excitation coil  33  is supplied with current. The coil  33  is wound about a tube  45  between plates  43  and  47 . The plate  43  abuts against the surface  29 . The armature  35  extends through a hole  46  formed through the plate  43  and is connected at its leading end  37  to the element  26  to move the element  26  between its coupling and uncoupling positions. The armature  35  also extends through an aperture  38  formed through the tube  45 . The opposite end  36  of the armature  35  has a locking ring  30  ( FIG. 1 ) which limits movement of the armature  35  in the aperture  38  towards the plate  12  by abutting against the lower surface of the tube  45  but allows the armature  35  to extend below the lower surface of the tube  45 . 
     The element  26  is pivotally connected to the leading end  37  of the armature  35  wherein the armature  35  pivotally moves the element  26  within the pocket  22  in response to reciprocating movement of the armature  35 . 
     The apparatus  15  also preferably includes a return spring  41 , which extends between the plate  43  and a shoulder in the outer surface of the tube  45 , to return the armature  35  and the tube  45  to their home position when the coil  33  is de-energized, thereby returning the element  26  to its uncoupling position. The apparatus also includes a spring  34  which urges the armature  35  to move the element  26  towards its coupling position. In other words, the biasing member, the spring  41 , urges the armature  35  via the tube  45  to a return position which corresponds to its uncoupling position of the element  26  while the biasing member or spring  34  urges the armature  35  and connected element  26  to its coupled position and opposes any force in the opposite direction. 
     The housing part  13  and/or the plate  47  preferably has holes to allow oil to circulate within the housing part  13 . Preferably, the at least one coil  33 , the housing part  13 , the tube  45  and the armature  35  comprise a low profile solenoid. The locking element  26  may be a metal (such as aluminum) injection molded (i.e. MIM) strut. 
     The housing part  13  has at least one apertured attachment flange  49  to attach the apparatus  15  to the coupling member  10  (corresponding aperture not shown) of the coupling assembly  11 . 
     The element  26  includes at least one and, preferably, two projecting leg portions  51  which provide an attachment location for the leading end  37  of the armature  35 . Each leg portion  51  has an aperture  53 . The apparatus  15  further comprises a pivot pin  55  received within each aperture  53  to allow rotational movement of the element  26  in response to reciprocating movement of the armature  35  wherein the leading end  37  of the armature  35  is connected to the element  26  via the pivot pin  55 . 
     Preferably, each aperture  53  is an oblong aperture which receives the pivot pin  55  to allow both rotation and translational movement of the element  26  in response to reciprocating movement of the armature  35 . Each locking strut  26  may comprise any suitable rigid material such as ferrous metal, (i.e. steel). 
       FIGS. 1 ,  2  and  3  show a magnetic field sensor or device, generally indicated at  100 . The device  100  may be a Hall-effect sensor which senses position of the strut  26 . The strut  26  may carry or support a rare-earth, automotive grade, magnet or pellet (not shown) which may be embedded in a hole formed in the outer surface of the strut  26 . In that case, the strut  26  is a non-ferrous strut such as an aluminum strut. Alternatively, and preferably, the strut  26  is a ferromagnetic strut. 
     The device  100  typically has three wires  108  (input, output and ground) and provides an industry standard, push-pull voltage output based on position of the strut  26  in the pocket  22 . The device  100  accurately detects the position of the strut  26  with a single output (i.e., voltage output). The device  100  is preferably mounted adjacent to and below the pocket  22  and the wires  108  extend through an aperture  109  formed in the plate  43  and through an aperture  110  formed through the side wall or skirt of the housing part  13 . The wires  108  are coupled to a solenoid controller ( FIG. 3 ) which, in turn, is coupled to a main controller and to a coil drive circuit which supplies drive signals to the coil  33  in response to control signals from the solenoid controller. The device  100  may be held in place by fasteners or by an adhesive so that an upper surface of the device  100  is in close proximity to the bottom surface of the strut  26  in the uncoupling position of the strut  26 . 
     The sensor  100  is typically back-biased when the strut  26  is ferromagnetic and typically includes a Hall sensor or sensing element mounted on a circuit board  114  on which other electronics or components are mounted, as is well-known in the art. The sensor  100  is preferably back-biased in that it includes a rare-earth magnet  112  which creates a magnetic flux or field which varies as the strut  26  moves. The sensor  100  may comprise a back-biased, Hall Effect device available from Allegro Microsystems. 
     In other words, the device  100  is preferably a back-biased device wherein the device includes a rare earth pellet or magnet whose magnetic field varies as the strut  26  moves towards and away from its uncoupled position. The variable magnetic field is sensed by the magnetic sensing element of the device  100 . 
     The output signal from the device  100  is a feedback signal which is received by the solenoid controller which, in turn, provides a control signal to the circuit which, in turn, provides drive control signals to control current flow to the coil  73 . By providing feedback, the resulting closed-loop control system has improved sensitivity, accuracy and repeatability. 
     The electromechanical apparatus  15  of the exemplary clutch assembly  11  may be carried by a driving member of the clutch assembly  11  or a driven member of the assembly  11 . Moreover, the strut  26  of the exemplary clutches assemblies may have any suitable configuration depending on whether the assembly is a planar coupling assembly as shown herein or a rocker coupling assembly (not shown). Also, each strut or rocker (in a radial coupling assembly) may have a middle portion that is thicker than each end portion of the strut or rocker. 
     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.