Abstract:
A harmonic balancer assembly is provided including a drive plate adapted to be attached to a crankshaft or other drive shaft. A first circumferentially extending elastomeric ring is connected to an axial face of the drive plate. An inertia ring is provided which also includes an axial face that is connected to the first elastomeric ring. A drive element can be connected to or engaged with the inertia ring in order to transmit torque from the drive plate to a further element in a drive train. The inertia ring can be connected to a pulley, a torque converter, or other transmission element in order to, for example, transfer torque from a crankshaft to a further transmission component or to transfer torque to a separate power take off.

Description:
INCORPORATION BY REFERENCE 
       [0001]    The following documents are incorporated herein by reference as if fully set forth: U.S. Provisional Patent Application No. 61/986,448, filed Apr. 30, 2014. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention is related to the field of harmonic balancers. More particularly, the invention is directed to a reduced axial length harmonic balancer that can be used in connection with an internal combustion engine to transfer the power to the transmission. 
       BACKGROUND 
       [0003]    In order to increase fuel economy, automotive design has recently concentrated on reducing weight as well as reducing the size of various components, including the power drive train. One improvement has resulted in the auxiliary drives being removed from the front of an engine and being driven via a transmission accessory drive. This has allowed a reduction in the overall length of the power train as these auxiliary drives are now driven via a transmission take-off. 
         [0004]    It would be desirable to provide a further reduction in the length of the power train. It would also be desirable to provide a reduced axial length harmonic balancer that can be used in connection with various drive shafts where torque undulations from the input side can be absorbed or otherwise addressed in order to reduce torque fluctuations on the output side. 
       SUMMARY 
       [0005]    In one aspect, a harmonic balancer assembly is provided. The assembly includes a drive plate adapted to be attached to a crankshaft or other drive shaft. A first circumferentially extending elastomeric ring is connected to an axial face of the drive plate. An inertia ring is provided which also includes an axial face that is connected to the first elastomeric ring. A drive element can be connected to or engaged with the inertia ring in order to transmit torque from the drive plate to a further element in a drive train. For example, the inertia ring can be connected to a pulley, a torque converter, or other transmission element in order to, for example, transfer torque from a crankshaft to a further transmission component or to transfer torque to a separate power take off via the pulley. 
         [0006]    Preferably, holes, depressions, or voids are located in at least one of the drive plate or the inertia ring in a connection area to the elastomeric ring. This allows a strong mechanical connection between the elastomeric ring and the drive plate. 
         [0007]    Preferably, the elastomeric ring is at least one of vulcanized, bonded, or adhered to the drive plate and the inertia ring. 
         [0008]    In a further improvement of the invention, the drive plate includes locating tabs that contact an inner radial surface of the first elastomeric ring. Further, the drive plate can include centering tabs for the inertia ring. The drive plate is preferably a punched or stamped sheet metal part, and the locating tabs and centering tabs can be punched out during formation of the drive plate. 
         [0009]    In another aspect of the invention, depending upon the torque to be transferred, a support plate is connected to the drive plate. A second circumferentially extending elastomeric ring is connected to an opposite axial face of the inertia ring from the first elastomeric ring. The second elastomeric ring is also connected to an axial face of the support ring on an opposite side from the inertia ring. 
         [0010]    In a preferred arrangement, the first and second elastomeric rings are connected to the drive plate, the inertia ring, and the support plate by at least one of a vulcanized, bonded, or adhered connection. 
         [0011]    Preferably, the support plate can also include locating tabs that radially contact an inside of the second elastomeric ring. This support plate may also include centering tabs for the inertia ring, depending upon the particular configuration. The support plate is preferably a stamped sheet metal part and the locating tabs and centering tabs may be formed during the stamping process. 
         [0012]    In another aspect, a harmonic balancer for a rotary drive is provided including a drive plate adapted to be attached to a drive shaft, as well as a first circumferentially extending elastomeric ring connected to an axial face of the drive plate. An inertia ring is provided having an axial face connected to the first elastomeric ring, and a driven element is connected to the inertia ring. Here, a reduced axial length harmonic balancer is provided that can be used in connected with various types of drives in order to smooth out or absorb pulses or non-uniformity in the angular velocity in the drive so that these pulses are not transmitted through to the driven element. 
         [0013]    Here, the elastomeric ring is preferably at least one of vulcanized, bonded, or otherwise adhered to the drive plate and the inertia ring. 
         [0014]    The driven element can be, for example, a pulley, a torque converter, a gear ring, or other drive element. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS  
         [0015]    The foregoing Summary as well as the following Detailed Description will be best understood when read in conjunction with the appended drawings which show a preferred embodiment of the invention. In the drawings: 
           [0016]      FIG. 1  is a cross-sectional view through a first embodiment of a harmonic balance according to the present invention. 
           [0017]      FIG. 2  is a cross-sectional view of a harmonic balancer according to a second embodiment of the invention. 
           [0018]      FIG. 3  is a view taken along lines  3 - 3  in  FIG. 2  showing a portion of an axial face of the support plate. 
           [0019]      FIG. 4  is an opposite axial view to  FIG. 3  taken along lines  4 - 4  in  FIG. 2  showing a portion of an opposite axial face of the drive plate. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0020]    Certain terminology is used in the following description for convenience only and is not limiting. The words “front,” “rear,” “upper” and “lower” designate directions in the drawings to which reference is made. The words “inwardly” and “outwardly” refer to directions toward and away from the parts referenced in the drawings. These terms and terms of similar import are for ease of description when referring to the drawings and should not be considered limiting. “Axially” refers to a direction along the axis of a shaft or similar object. A reference to a list of items that are cited as “at least one of a, b, or c” (where a, b, and c represent the items being listed) means any single one of the items a, b, or c, or combinations thereof. 
         [0021]    For elements of the invention that are identical or have identical actions, identical reference symbols are used. The illustrated embodiments represent merely examples for how the device according to the invention could be equipped. They do not represent a conclusive limitation of the invention. 
         [0022]    Referring now to  FIG. 1 , a harmonic balancer assembly  10  is shown according to a first preferred embodiment of the invention. The harmonic balancer  10  includes a drive plate  20  that is adapted to be attached to a crankshaft  12  via a mounting bolt  14 . A first circumferentially extending elastic ring  44  is connected to an axial face of the drive plate  20 . An inertia ring  40  having a first axial face is connected to the first elastomeric ring  44  by the first axial face. A support plate  30  is connected to the drive plate  20 , preferably via fasteners, such as rivets  36 . A second circumferentially extending elastomeric ring  46  is connected to a second axial face of the inertia ring  40 , opposite from the first axial face of the inertia ring  40  and from the first elastomeric ring  44 . The second elastomeric ring  46  is connected to an axial face of the support plate  30  on an opposite side from the inertia ring  40 . 
         [0023]    Preferably, the first and second elastomeric rings  44 ,  46  are made from rubber, synthetic rubber, or another suitable elastomeric material. The elastomeric rings  44 ,  46  are at least one of vulcanized, bonded, or otherwise adhered to the drive plate  20  as well as the support plate  30  and the inertia ring  40 . 
         [0024]    The drive plate  20  preferably includes locating tabs  24  that contact an inner radial surface of the first elastomeric ring  44 . A plurality of the locating tabs  24  are preferably provided, spaced apart circumferentially on the drive plate  20 . For example, there can be eight equally spaced locating tabs  24 . The drive plate  20  preferably also includes centering tabs  22  that engage an end surface of the crankshaft  12  for centering the harmonic balancer  10  on the crankshaft. A plurality of the centering tabs  22  are preferably also provided, and are spaced apart circumferentially. 
         [0025]    The support plate  30  can also include locating tabs  34  that radially contact an inside of the second elastomeric ring  46 . The support plate  30  may also include centering tabs  32  for the inertia ring  40 . Preferably there are a plurality of the locating tabs  34  that are spaced apart circumferentially, and there are also a plurality of the centering tabs  32  spaced apart circumferentially on the support plate  30 . 
         [0026]    Preferably, the drive plate  20  is a punched or stamped sheet metal part. The support plate  30  is preferably also a punched or stamped sheet metal part. The centering tabs  32  as well as the locating tabs  24 ,  34  are preferably formed during the punching or stamping process of the drive plate  20  as well as the support plate  30 . 
         [0027]    Using this arrangement, the inertia ring  40  is sandwiched between the two elastomeric rings  44 ,  46 . The drive plate  20  and the support plate  30  are preferably riveted together via rivets  36  providing a pre-load on the elastomeric rings  44 ,  46  and trapping the inertia ring. The locating tabs  24 ,  34  and the centering tabs  32  for the inertia ring provide for easier assembly of the harmonic balancer  10 , and the centering tabs  22  for the crankshaft allow for easier installation. Based on this construction using the elastomeric rings  44 ,  46 , the overall harmonic balancer  10  has a shorter axial length than the prior known harmonic balancers. The inertia ring  40  can be connected to a driven element illustrated in broken lines as  48 , which can be a pulley, torque converter or other transmission element. 
         [0028]    Referring to  FIGS. 2-4 , a second embodiment of a harmonic balancer  110  is shown. The second embodiment of the harmonic balancer  110  is a simplified embodiment in which the harmonic balancer  110  includes the drive plate  120  with a circumferentially extending elastomeric ring  144  connected to an axial face of the drive plate  120 . An inertia ring  140  is provided having an axial face connected to the elastomeric ring  144 . A driven element can then be connected to the inertia ring  140 . In this embodiment, the elastomeric ring  144  is connected to both the support plate  120  as well as the inertia ring  140  by at least one of vulcanizing, bonding, or adhering. 
         [0029]    Preferably, the drive plate  120  includes centering tabs  122 , preferably circumferentially spaced apart on the drive plate  120 , for connecting to a drive shaft, such as the crankshaft  12  shown in  FIG. 1 . Additionally, the drive plate  120  includes centering tabs  132  for the inertia ring  140  as well as locating tabs  124  for the elastomeric ring  144 . These tabs are preferably formed in the drive plate  120  during the punching or stamping process used to form the drive plate  120 . 
         [0030]    As shown in detail in  FIGS. 3 and 4 , preferably holes  138  are punched in the drive plate  120  in the area of the connection to the elastomeric ring  144 . Additionally, holes  142  are preferably also punched into the inertia ring in a connection area to the elastomeric ring  144 . These holes can be in the form of through openings, depressions, or other voids and are used to ensure a strong mechanical connection between the elastomeric ring and the drive plate  120  and the inertia ring  140 . This is particularly preferred when the elastomeric ring is a vulcanized rubber ring and vulcanized material flows into and/or through the holes  138 ,  142  to provide a secure connection. 
         [0031]    The holes in the drive plate  120  and the inertia ring  140  can be used in connection with the first embodiment as well to provide a firm connection between the elastomeric rings  44 ,  46  and the drive plate  20 , the support plate  30  and the inertia ring  40 . 
         [0032]    In the first preferred embodiment, the elastomeric rings  44 ,  46  may be made of suitable natural or synthetic elastomers with the desired properties for the particular application, and the thickness will vary depending upon the torque to be transferred and other factors. A thickness in the range of 2-3 mm is believed to be suitable; however, other thicknesses can be used. This provides the harmonic balancer function with a reduced overall thickness as it avoids the use of coil springs and relies on the elastomeric rings connected to the axial faces of both the drive plate  20 , the support plate  30  as well as the inertia ring  40 . 
         [0033]    In the second preferred embodiment, the elastomeric ring  144  is preferably also made from suitable natural or synthetic elastomers. The thickness of the elastomeric ring  144  can also vary depending upon the torque to be transferred and other factors. A thickness in the range of 2-4 mm is believed to be suitable; however, other thicknesses can be used. This arrangement also provides for a reduced axial thickness. 
         [0034]    Having thus described the present invention in detail, it is to be appreciated and will be apparent to those skilled in the art that many physical changes, only a few of which are exemplified in the detailed description of the invention, could be made without altering the inventive concepts and principles embodied therein. It is also to be appreciated that numerous embodiments incorporating only part of the preferred embodiment are possible which do not alter, with respect to those parts, the inventive concepts and principles embodied therein. The present embodiment and optional configurations are therefore to be considered in all respects as exemplary and/or illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all alternate embodiments and changes to this embodiment which come within the meaning and range of equivalency of said claims are therefore to be embraced therein.