Abstract:
A driven disc assembly is provided. The backing plates have right angle depression sections that surround mounting holes of a clutch disc. The thickness of the backing plates are enlarged from their normal thickness causing a top surface of the backing plates to axially clear heads of conventional rivets. The thickness of the friction buttons on the backing plates can then be reduced to their minimal effective use thickness.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a Continuation of U.S. patent application Ser. No. 13/891,724, filed May 10, 2013 which is a Continuation-In-Part of U.S. patent application Ser. No. 13/873,626, filed Apr. 30, 2013 which claims priority to U.S. Provisional Patent Application No. 61/645,885, filed May 11, 2012. The disclosures of the above noted applications are incorporated herein by reference. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The field of the present invention is that of friction or driven disc assemblies. The present invention is particularly applicable in driven disc assemblies in clutches utilized to selectively connect an engine of a motorized vehicle with a transmission of the motorized vehicle, especially vehicles such as large trucks. 
       BACKGROUND OF THE INVENTION 
       [0003]    Many large motorized vehicles have a clutch assembly to selectively connect an engine of the vehicle with the vehicle transmission. The workings of such a clutch assembly can be discovered by a review of U.S. patent application Ser. No. 12/807,971, Franke, entitled Dry Clutch Having Solid Lubricant Friction Stabilization Inserts, filed Sep. 17, 2010 (the disclosure of which is incorporated by reference herein). Referring to  FIGS. 1 ,  7  and  11 , a conventional driven disc assembly  9  includes a disc member  11 . The disc member  11  is torsionally connected with a damper unit  13  which spring dampens torsional vibrations delivered to an input shaft of a transmission. The disc member  11  is typically a thin metallic plate having along it&#39;s periphery a series of blades or wings  15 . The wings  15  on opposing faces have connected thereto a friction pad  17 . The friction pad  17  consists of a backing plate  19  with a connected friction material, commonly a ceramic friction material  21 . The friction material  21  is referred to as the button in many applications. The friction pads  17  are connected to the friction disc  11  by a series of flathead semi-tubular rivets  23 . Referring the addition to  FIG. 11 , the flathead semi-tubular rivets  23  have a purchased head  25  and a peened head  27  formed by an assembly operation. 
         [0004]    The overall axial width  29  (adjacent its outer diameter) of the driven disc assembly  9  based upon the design of the driven disc assembly  9  and a clutch intermediate plate and/or clutch cover assembly that the driven disc assembly interacts with. The overall axial width (sometimes also referred to as height) of the buttons  21  is determined by two factors. The first factor is the expected wear life of the button and is determined by a dimension  31 . The second dimension is a dimension  33  that is a width of the friction material on the backing plate required for clearance of the rivet head  27  (or on the other side  25 ). Accordingly, the amount of friction material of a width  33  is essentially wasted material that cannot be utilized. Typically, the ceramic material making up the button is a very expensive material that typically far exceeds the cost of the backing plate  19 . The backing plate is typically a metallic material. 
         [0005]    One attempt to eliminate or to make more use wasted button material is provided in  FIGS. 6 and 10 . In  FIGS. 6 and 10 , a recessed rivet driven disc assembly  41  is provided. In the driven disc assembly  41 , the backing plates  43  have adjacent to the rivet holes recesses  45 . Because of the recesses  45 , a specialty axially shortened rivet  47  is utilized. The driven disc assembly  41  in  FIGS. 6 and 10  does provide an advantage of shortening the rivet, allowing a greater portion of the buttons  48  to be utilized. However, since the overall thickness  29  of the driven disc assembly is determined by other design criteria, the recessed design of driven disc assembly  41  mandates even thicker buttons  48  (to achieve an overall axial thickness  29 ) thereby providing a button with more excess material which cannot be utilized (due to clutch design) and thereby increasing driven disc assembly cost. 
         [0006]    Referring to  FIGS. 2 through 5  and  9 , an alternative design driven disc assembly  61  has been put forth. Driven disc assembly  61  has an overall axial width  29 . In driven disc assembly  61 , the disc  11  can be utilized. Driven disc assembly  61  has a backing plate  63  that has an elevated flat section  67  that is elevated by a series of dimple mounds  69 . The dimple mounds  69  raise an outer surface of the backing plate  63  outward so that the button  71  can have an effective thickness  31  thereby eliminating the non-utilized thickness  33  of the button in the conventional used driven disc assembly  9 . Although this design did provide the advantages desired in reduction of friction material utilized, the non-flat contact between the section  67  of the backing plate with the disc caused the backing plate  63  to buckle due to the lack of adequate heat transfer from the backing plate  63  to the disc  11 . 
         [0007]    It is desirable to provide a driven disc assembly wherein the thickness of the friction button can be reduced to its effective use to minimize the costs of the driven disc assembly without compromising operational performance. 
       SUMMARY OF THE INVENTION 
       [0008]    To meet the above-noted and other desires, a revelation of the present invention is brought forth. The present invention brings forth a driven disc assembly wherein the clutch disc has holes aligned for connection of the backing plates. The backing plates have right angled depression sections surrounding the backing plate holes. The thickness of the backing plates are enlarged from their normal thickness causing a top surface of the backing plates to axially clear the head of a conventional rivet. The thickness of the friction buttons can then be reduced to their minimal effective thickness. 
         [0009]    Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]    The present invention will become more fully understood from the detailed description and the accompanying drawings, wherein: 
           [0011]      FIG. 1  is a partial perspective view of a conventional driven disc assembly; 
           [0012]      FIG. 2  is a perspective view of a prior art backing plate having a dimple or quilted surface which is an alternative to a backing plate shown in  FIG. 1 ; 
           [0013]      FIG. 3  is another perspective view of the same backing plate shown in  FIG. 2 ; 
           [0014]      FIG. 4  is a partial perspective view of the backing plate shown in  FIGS. 2 and 3  assembled to a disc to partially illustrate a driven disc assembly; 
           [0015]      FIG. 5  is a view of a backing plate shown in  FIGS. 2-4  wherein the backing plate is turned upside down to illustrate its dimples; 
           [0016]      FIG. 6  is a perspective view shown partially in section of a prior art driven disc assembly which is an alternative to the conventional driven disc assembly shown in  FIG. 1 ; 
           [0017]      FIG. 7  is a perspective view partially sectioned of the conventional driven disc assembly shown in  FIG. 1 ; 
           [0018]      FIG. 8  is a perspective view of a preferred driven disc assembly accordingly to the present invention; 
           [0019]      FIG. 9  is a sectional view of the driven disc assembly shown in  FIGS. 2-5 ; 
           [0020]      FIG. 10  is a sectional view of the driven disc assembly shown in  FIG. 6 ; 
           [0021]      FIG. 11  is a sectional view of a conventional driven disc assembly shown in  FIGS. 1 and 7 ; 
           [0022]      FIG. 12  is an enlarged side sectional view of the preferred embodiment driven disc assembly shown in  FIG. 8 ; and 
           [0023]      FIG. 13  is an enlarged side sectional view of an alternate preferred embodiment dry disc assembly. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0024]    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. 
         [0025]    Referring to  FIGS. 8 and 12 , an inventive low profile button dual face clutch friction plate or disc driven assembly  107  has an overall axial width  29 . The disc driven assembly  107  has a disc  111 . The disc  111  has a series of mounting holes  114 , which are enlarged in comparison to the mounting holes shown formed in the disc drive assembly  9  disc  11 . However, in other aspects, the disc  111  is essentially identical to the disc  11 . A backing plate  116  is provided which typically has a greater thickness  136  (typically a total thickness between 0.080 and 0.110 inches) than the backing plates previously described. The backing plate  116  has a mounting hole  118 . Hole  118  is smaller in diameter then the disc hole  114  and is aligned therewith. The hole  118  is surrounded by a right angle depression section formed by a stamped semi-pierced section  120 . The semi-pierced section  120  has an axial displacement thickness  125 . The axial displacement thickness  125  is less than an axial thickness  31  of the button  128 . An axially inner section  122  of the semi-pierced section  118  is inserted within the clutch disc holes  114 . There is an axial gap  124  between inner axially extreme portions  127  of the opposing backing plates. A lateral abutting contact thickness  126  of the semi-pierced section to the rivet  23  is greater than the thickness  31  (typically between 0.040 and 0.075 inches) of the friction button  128 . Due to the increased thickness of backing plates  116 , the backing plates  116  provide a major flat surface section  130  in adjacent contact with the friction button  128  that is beyond or above the heads  27  or  25  of the rivets  23  (identical to the rivets  23  utilized in the driven disc assembly  9  shown in  FIG. 11 ). The gap  124  between the extreme axially extreme ends  127  of the backing plates ensure that the rivets hold the two backing plates  116  in maximum tension after assembly to the disc  111 . 
         [0026]    Between the semi-pierced section  120  of the backing plates and the mounting hole  114  of the disc is an installation gap  134 . The installation gap is primarily to ensure the proper clearance needed for the assembly operation. The semi-pierced section  120  has an abutting lateral contact interface  131  with a tubular portion  133  of the rivet. The length of the lateral abutting contact of the semi-pierced section with the rivet noted as width  126  is greater than the width  31  of the button  128 . The contact section  120  along its outer diameter has an abutting lateral interface  139  of an axial width  140 . The axial width  140  in most instances will be at least equal or greater than the width  31  of the button minus 0.035 inches (or the width of the button  128  is no more than 0.035 inches more than that of the width  140 ) and in most applications will be between 0.040 to 0.055 inches in total width. The radial width  138  of the semi-pierced portion in most instances will be greater than the radial width  135  of the tubular wall  133  of the rivet. Due to the abutting lateral interface  139  of the semi-pierced portions  120  with the disc hole  114  and also due to the fact that the radial width  138  of the semi-pierced portion  120  is greater than the radial width of the rivet  135 , the sheer strength of the connection of the backing plate  116  to the disc  111  is significantly greater than the sheer strength of the connection of the backing plates  119  to the disc  11  of the driven disc assembly  9  which is the conventional design. 
         [0027]    Referring to  FIG. 13 , disc driven assembly  207  has buttons  128  with an axial width  31  in a manner similar or identical to disc driven assembly  107  described in  FIG. 12 . Additionally, disc driven assembly  207  has an overall axial thickness  29  and utilizes a disc  11  identical to the disc  11  described in  FIG. 11  for the conventional disc driven assembly  9  and also utilizes rivets  23  identical to those utilized for disc driven assemblies  9  and  12 . The disc driven assembly  207  has backer plates  216  with right angle depressions  220  having an axial displacement thickness  125  which is typically less than the axial thickness  31  of the button  128 . The backer plates have a thickness  136 ′ which typically is close or identical to thickness  136  of driven disc assemblies  116  of driven disc assembly  107 . The backer plate  216  has lateral contact with the tubular portion  133  of the rivet of an axial thickness  129  that is typically less than the axial thickness  31  of the button  128 . The heads  25  and  27  of the rivets  23  axially capture the right angle depressions  220  of the backing plates  216  together to form the driven disc assembly. 
         [0028]    The description of the invention is merely exemplary in nature and, thus, variations that do not depart from the gist of the invention 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.