Abstract:
A kit for improving the performance of a clutch assembly, the clutch assembly including an input housing configured to receive an interleaved stack of plural friction elements and plural steel plates through an open end of the housing, the kit including at least one steel plate configured and dimensioned to be received through the open end of the housing and disposed in mating relationship with a terminal one of the plural friction elements, at least one friction disk configured and dimensioned to be received through the open end of the housing and disposed in mating relationship with the at least one steel plate to form in combination with the plural friction elements and plural steel plates an extended interleaved stack, with the at least one friction disk forming a new terminal friction element, and a retaining ring configured and dimensioned to be secured over the open end of the housing and including an integrally formed, annular inner friction surface adapted to confront the new terminal friction element to directly receive forces applied through the clutch assembly.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention generally relates to the field of clutches. In particular, the present invention is directed to a clutch assembly performance enhancement apparatus and method. 
       BACKGROUND 
       [0002]    Transmissions include, among other components, a clutch assembly. The interposition of the clutch assembly between a drive shaft and a driven shaft permits the drive shaft, connected to a motor or an engine, to be coupled, releasably, to the driven shaft. This coupling through the clutch assembly may cause the driven shaft to rotate at the same rate as the drive shaft. It may also enable a driven shaft to rotate at a different rotation rate as the drive shaft, or be completely decoupled from the driven shaft. 
         [0003]    One component of the clutch assembly that enables the releasable coupling of the drive shaft to the driven shaft is a stack of friction elements interleaved with steel plates. This interleaved stack can transfer torque from the drive shaft to the driven shaft, or it can be decoupled from one of the shafts, thereby preventing the transfer of torque. Given this arrangement, a clutch assembly is limited in the amount of torque that it can transfer from the driven shaft to the drive shaft in part by the torque that the interleaved stack can withstand: When an upper torque limit is exceeded, the interleaved disks can slip with respect to one another, allowing the clutch to slip excessively, degrading performance and increasing wear. 
       SUMMARY OF THE DISCLOSURE 
       [0004]    In one implementation, the present disclosure is directed to a kit for improving the performance of a clutch assembly. The clutch assembly comprises an input housing configured to receive an interleaved stack of plural friction elements and plural steel plates through an open end of said housing, said kit comprising at least one steel plate configured and dimensioned to be received through said open end of said housing and disposed in mating relationship with a terminal one of said plural friction elements; at least one friction disk configured and dimensioned to be received through said open end of said housing and disposed in mating relationship with said at least one steel plate to form in combination with said plural friction elements and plural steel plates an extended interleaved stack, with said at least one friction disk forming a new terminal friction element; and a retaining ring configured and dimensioned to be secured over said open end of said housing and including an integrally formed, annular inner friction surface adapted to confront the new terminal friction element to directly receive forces applied through the clutch assembly. 
         [0005]    In another implementation, the present disclosure is directed to a kit for improving the performance of a clutch assembly. The clutch assembly comprising an input housing configured to receive an interleaved stack of plural friction elements and plural steel plates through an open end of said housing, said kit comprising an apply-plate having an annular recessed face disposed on a surface of said apply-plate, said apply plate positioned to cooperate with an apply-ring, the apply-ring disposed within the input housing; at least one steel plate configured and dimensioned to be received through said open end of said housing and disposed in mating relationship with a terminal one of said plural friction elements; at least one friction disk configured and dimensioned to be received through said open end of said housing and disposed in mating relationship with said at least one steel plate to form in combination with said plural friction elements and plural steel plates an extended interleaved stack, with said at least one friction disk forming a new terminal friction element; and a retaining ring configured and dimensioned to be secured over said open end of said housing and including an integrally formed, annular inner friction surface adapted to confront the new terminal friction element to directly receive forces applied through the clutch assembly. 
         [0006]    In yet another implementation, the present disclosure is directed to a method of improving the performance of a clutch assembly. The clutch assembly comprising a stack of interleaved plural friction disks and plural steel plates, and a housing configured to receive an interleaved stack of plural friction elements and plural steel plates through an open end of said housing, said method comprising fabricating a receiving surface on the open end of the housing; inserting at least one additional friction disk into the clutch assembly housing, the additional friction disk configured and dimensioned to be received through said open end of said housing and disposed in mating relationship with said at least one steel plate to form in combination with said plural friction elements and plural steel plates an extended interleaved stack, with said at least one friction disk forming a new terminal friction element; inserting at least one additional steel plate into the clutch assembly configured and dimensioned to be received through the open end of the housing and disposed in mating relationship with a terminal one of the plural friction elements; and enclosing the receiving end of the clutch assembly housing using a retaining ring mounted to the receiving surface, a friction surface formed on an inner side thereof and adapted to directly receive forces applied through the clutch assembly. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0007]    For the purpose of illustrating the invention, the drawings show aspects of one or more embodiments of the invention. However, it should be understood that the present invention is not limited to the precise arrangements and instrumentalities shown in the drawings, wherein: 
           [0008]      FIG. 1  is an exploded isometric view of an exemplary embodiment of a clutch assembly; 
           [0009]      FIG. 2  is a perspective view of an exemplary embodiment of a modified apply-ring having an annular recessed face; and 
           [0010]      FIG. 3  is a cross-sectional view of a portion of a modified input housing and a retaining ring, each having mating alignment features. 
       
    
    
     DETAILED DESCRIPTION 
       [0011]    Embodiments of the present invention disclosed herein include apparatus and methods for making and using a kit to improve the performance of a clutch assembly used as part of a drive-train that is connected to a motor or an engine. Certain exemplary embodiments disclosed herein are particularly well suited for use with the following General Motors transmissions: 700-R4/4L60 from production year 1982 to production year 1993; 4L60E from production year 1992 to at least production year 2010; 4L65E from production year 2001 to production year 2005; and 4L70E from production year 2005 to at least production year 2010. While these transmissions are identified, those skilled in the art will appreciate that the teachings of the present disclosure are not limited to these transmissions, nor limited to vehicle transmissions generally. Indeed, the broad concepts of the present disclosure may be applied to any of a number of systems in which a motor or engine drives a drive shaft that, in turn, is connected to a driven shaft via a clutch assembly. 
         [0012]    In the exemplary embodiments disclosed herein, a kit may be used to improve the performance of a clutch assembly, including increasing the upper toque limit, by, in one embodiment, modifying an existing clutch to permit additional friction elements and additional steel plates to be added to an interleaved stack. In another exemplary embodiment, the kit may be used to improve the performance of a clutch assembly by rigidly connecting a retaining ring to a modified input housing in order to add an additional friction element to the interleaved stack without occupying any of the limited volume within the clutch assembly housing. The rigid connection of the retaining ring to the modified input housing may also improve the performance of the clutch assembly by increasing the amount of pressure that the retaining ring can withstand before unintentionally separating from the modified input housing. 
         [0013]    Turning now to the figures,  FIG. 1  depicts an exploded isometric view of clutch assembly  100  that includes clutch kit  104 . Clutch kit  104  may be used to improve, for example, the upper torque limit of clutch assembly  100 . Kit  104  includes an apply-plate  106  having an annular recessed face  108  (also shown in  FIG. 2 ), an interleaved stack  112  of friction elements  116  and steel plates  120 , a retaining ring  124  that includes an inner friction surface  128 , bolts  132 , springs  136 , and spring guides  140 . 
         [0014]    Components of kit  104  are in mechanical communication with various elements of clutch assembly  100 , including modified input housing  144 . Modified input housing  144  houses the components of clutch assembly  100 , including the components of kit  100 , and is in mechanical communication with drive shaft  148  and the driven shaft. While in one exemplary embodiment, the diameter of modified input housing  144  may be approximately six inches, those skilled in the art will appreciate that other examples can range in diameter from only one or two inches to over twelve inches, depending on the application. Furthermore, as those skilled in the art will appreciate, modified input housing  144  can be fabricated from any number of materials including aluminum, aluminum alloys, steel, and steel alloys including stainless steel. As known to those skilled in the art, these materials can be cast, machined, rolled, or otherwise fabricated to meet the design criteria of the specific application. 
         [0015]    Components of kit  104  are also in mechanical communication with other mechanical components of clutch assembly  100  including an apply-piston  152 , an apply-ring  156 , and other elements necessary for the operation of a clutch not shown or described herein, but well known to those skilled in the art. In the exemplary embodiment depicted in  FIG. 1 , apply-piston  152 , apply-ring  156 , and apply-plate  106  can cooperate in order engage or disengage interleaved stack  112 , thereby coupling or decoupling drive shaft  148  from the driven shaft. 
         [0016]    One exemplary mechanism by which kit  104  can increase the upper torque limit of clutch assembly  100  is to replace OEM clutch assembly components with analogous components having reduced thicknesses compared to the OEM clutch components in order to reallocate space within modified input housing  144  from these components to additional friction elements  116  and/or steel plates  120  of interleaved stack  112 . In one such exemplary embodiment, apply-plate  106 , as an element of kit  104 , is thinned in comparison to a conventional apply-plate in order to increase the space within modified input housing  144  available for additional friction elements  116  and/or steel plates  120 . The addition of friction elements  116  and/or steel plates  120 , can increase the upper torque limit of clutch assembly  100 . In this example, apply-plate  106  has a thickness of approximately 0.2 inches to approximately 0.5 inches, an outer diameter of approximately 5 inches to approximately 6 inches, and a width of approximately 0.5 inches. As described above, those skilled in the art will appreciate that these dimensions can be varied as required by the particular design requirements of a clutch assembly without departing from the concepts of the present disclosure. In other examples, OEM friction elements and steel plates may be replaced by friction elements  116  and steel plates  120  having reduced thicknesses compared to their OEM analogues, permitting additional friction elements and steel plates to be inserted into modified input housing  144 , and thereby improving the upper torque limit attainable by clutch assembly  100 . 
         [0017]    Continuing with this exemplary embodiment, apply-plate  106  may include an annular recessed face  108 , as shown in  FIG. 2 , disposed on a surface of the apply-plate that is substantially concentric with the circumference of the apply-plate. Annular recessed face  108  may mate with apply-ring  156  upon actuation of the apply-piston  152 . Annular recessed face  108 , because of its reduced thickness when compared to the non-recessed portion of apply-plate  106 , provides space within modified input housing  144  that may be reallocated to additional friction elements  116  and/or steel plates  120  by, for example, reducing the spacing between apply-piston  152 , apply-ring  156 , and apply-plate  106 . The reduced thickness of apply-plate  106  only at annular recessed face  108  enables the apply-plate to remain sufficiently rigid because of the larger thickness region of the apply-plate bordering the annular recessed face. This additional rigidity can maintain proper functioning of apply-plate  106  even under high operating loads exerted on the apply-plate by apply-piston  152  and apply-ring  156 . Apply-plate  106 , as well as apply-piston  152  and apply-ring  156 , can be fabricated from any number of materials including aluminum, aluminum alloys, steel, and steel alloys including stainless steel. As known to those skilled in the art, these materials can be cast, machined, rolled, or otherwise fabricated to meet the design criteria of the clutch assembly. 
         [0018]    Apply-plate  106  may also be in mechanical communication with return spring  136 . Return spring  136  may be guided by a spring retainer  140  and in communication with both apply-plate  106  and retaining ring  124 . The urging force provided by return spring  136  may return apply-plate  106  to a default position after the apply-plate is moved by apply-piston  152  that has been actuated so as to move apply-ring  156 . In this example, return spring  136  can be approximately 1.2 inches to approximately 1.5 inches in length, with a load of approximately 2 pounds to 2.5 pounds at approximately 1.2 inches, and a load of approximately 4 pounds to 6 pounds at approximately 1.1 inches. Those skilled in the art will appreciate that return spring  136  can be designed to a wide variety of dimensions and loads depending on the design features needed for its performance as part of kit  104 . 
         [0019]    In another exemplary embodiment of the present invention, an inner friction surface  128  is added to the side of retaining ring  124  facing interleaved stack  112 , thereby providing an additional element of the interleaved stack that can, in turn, increase the upper torque limit of the clutch assembly. Providing inner friction surface  128  disposed on the interleaved-stack-face of retaining ring  124  is a spatially-efficient manner of providing the additional friction element because the underlying structural support for the friction element, that is the retaining ring, does not occupy space within modified input housing  144 . This in turn, can preserve space within modified input housing  144  for even more additional friction elements  116  and/or steel plates  120 , thereby further increasing the upper torque limit of the clutch assembly. 
         [0020]    As shown in  FIG. 3 , another mechanism by which kit  104  can improve the performance of clutch assembly  100  is to connect modified input housing  144  and retaining ring  124  using connecting means that contribute to an increase of the upper torque limit of the clutch assembly. In one exemplary embodiment, modified input housing  144  and retaining ring  124  can be connected using bolts  132 . Bolts  132  provide a rigid connection between modified input housing  144  and retaining ring  124 , thereby enabling the retaining ring to receive increased forces transferred to it by interleaved stack  112  without failing. In this example, and as shown in  FIG. 3 , the connection between modified input housing  144  and retaining ring  124  is facilitated by creating a receiving surface  304  on modified input housing  144 . Receiving surface  304  is a generally flat surface, fabricated by machining modified input housing  144 , on which retaining ring  124  is placed. Furthermore, receiving surface  304  contains threaded bores  308  that may be used to receive bolts  132  that rigidly connect retaining ring  124  to the receiving surface, thereby increasing the upper torque limit of the clutch assembly. In some examples, to facilitate assembly, modified input housing  144  may also include an alignment feature  312   a  that mates to an alignment feature  312   b  on retaining ring. 
         [0021]    One exemplary embodiment of a method using kit  104  to enhance the performance of clutch assembly  100  may begin by detaching an OEM end-ring from an OEM housing assembly. Upon detaching the end-ring, one or more additional friction elements  116  and/or steel plates  120  can added to interleaved stack  112 , thereby increasing the upper torque limit that clutch assembly can withstand. In some embodiments of the method, an entire OEM interleaved stack can be removed and replaced with interleaved stack  112  that includes additional friction elements  116  and/or steel plates  120 . 
         [0022]    This exemplary embodiment of the method may also include modifications to the OEM housing assembly so as to enhance upper torque limit that the clutch assembly can withstand. As explained above, upon detaching an OEM retaining ring, the OEM housing assembly can be modified to become modified housing assembly  144 , in accordance with above disclosure, by fabricating a generally flat receiving surface  304  on an open end of the input housing. Retaining ring  128  may be attached to flat surface  304  using bolts  132 . 
         [0023]    As explained above, retaining ring  128  can improve the performance of a clutch assembly by at least two mechanisms. In one mechanism, an inner friction surface  128  may be configured to be in mechanical communication with a terminal element of the interleaved stack. The addition of this inner friction surface has the effect of adding an element to interleaved stack  112  without occupying the limited space within assembly housing  144 . In another mechanism, the retaining ring can be attached to the modified input housing using bolts, rivets, welding, or other mechanical connect methods. Using these types of mechanical connections can provide a higher force threshold. These two embodiments also may be employed together. 
         [0024]    Exemplary embodiments have been disclosed above and illustrated in the accompanying drawings. It will be understood by those skilled in the art that various changes, omissions and additions may be made to that which is specifically disclosed herein without departing from the spirit and scope of the present invention.