Patent Publication Number: US-2021190172-A1

Title: Torsional vibration damper with a friction plate

Description:
TECHNICAL FIELD 
     The present disclosure relates to a torsional vibration damper with an idle damper hysteresis greater than a main damper hysteresis. 
     BACKGROUND 
     For known two-stage torsional vibration dampers, hysteresis is used to dampen vibration. For these known two-stage torsional vibration dampers, a hysteresis associated with an idle damper stage (for example at engine start-up) is less than a hysteresis associated with a main damper stage. 
     SUMMARY 
     According to aspects illustrated herein, there is provided a torsional vibration damper, including: a hub supported for rotation around an axis of rotation; a first damper stage including a first damper flange non-rotatably connected to the hub and a first spring engaged with the first damper flange; a second damper stage including a second damper flange and a second spring, radially off-set from the first spring, and engaged with the second damper flange; and a friction control plate non-rotatably connected to the hub, free of contact with the first spring and free of contact with the second spring, and directly engaged with the second damper stage. 
     According to aspects illustrated herein, there is provided a torsional vibration damper, including: a hub; a first damper flange non-rotatably connected to the hub; a first spring directly engaged with the first damper flange; a second damper flange directly engaged with the first spring; a second spring directly engaged with the second damper flange and radially off-set from the first spring; a first damper plate directly engaged with the second spring; and a friction control plate non-rotatably connected to the hub and in contact with the second damper flange or directly engaged with the second damper flange, free of contact or engagement with the first spring, and free of contact or engagement with the second spring. One of the first damper plate or the hub is arranged to receive a rotational torque as an input to the torsional vibration damper. An other of the first damper plate or the hub is arranged to transmit the rotational torque as an output of the torsional vibration damper. For the rotational torque less than a threshold value, the hub is arranged to rotate the friction control plate with respect to the second damper flange, and the second damper flange is non-rotatable with respect to the first damper plate. For the rotational torque equal to or greater than the threshold value, the hub is arranged to rotate the friction control plate with respect to the second damper flange, and the second damper flange is arranged to rotate with respect to the first damper plate. 
     According to aspects illustrated herein, there is provided a torsional vibration damper, including: a hub; a first damper flange non-rotatably connected to the hub; a first spring directly engaged with the first damper flange; a second damper flange directly engaged with the first spring; a second spring directly engaged with the second damper flange and radially off-set from the first spring; a damper plate directly engaged with the second spring; a friction control plate non-rotatably connected to the hub, free of contact or engagement with the first spring, and free of contact or engagement with the second spring; and a resilient element urging the friction control plate into contact with the second damper flange. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Various embodiments are disclosed, by way of example only, with reference to the accompanying schematic drawings in which corresponding reference symbols indicate corresponding parts, in which: 
         FIG. 1  is a front isometric view a torsional vibration damper with a friction control plate; 
         FIG. 2  is a back isometric view of the torsional vibration damper shown in  FIG. 1 ; 
         FIG. 3  is a front view of the torsional vibration damper shown in  FIG. 1 ; 
         FIG. 4  is an exploded view of the torsional vibration damper shown in  FIG. 1 ; 
         FIG. 5  is a cross-sectional view generally along line  5 - 5  in  FIG. 3 ; 
         FIG. 6  is a back view of the torsional vibration damper shown in  FIG. 1  with a damper plate removed; 
         FIG. 7  is a cross-sectional view generally along line  7 - 7  in  FIG. 3 ; 
         FIG. 8  is an isometric front view of a hub and the friction control plate of the torsional vibration damper shown in  FIG. 1 ; 
         FIG. 9  is an isometric view of the friction control plate in  FIG. 1 . 
     
    
    
     DETAILED DESCRIPTION 
     At the outset, it is appreciated that like drawing numbers on different drawing views identify identical, or functionally similar, structural elements of the disclosure. It is to be understood that the disclosure as claimed is not limited to the disclosed aspects. 
     Furthermore, it is understood that this disclosure is not limited to the particular methodology, materials and modifications described and as such may, of course, vary. It is also understood that the terminology used herein is for the purpose of describing particular aspects only, and is not intended to limit the scope of the present disclosure. 
     Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood to one of ordinary skill in the art to which this disclosure belongs. It is understood that any methods, devices or materials similar or equivalent to those described herein can be used in the practice or testing of the disclosure. 
       FIG. 1  is a front isometric view of torsional vibration damper  100  with a friction control plate. 
       FIG. 2  is a back isometric view of torsional vibration damper  100  shown in  FIG. 1 . 
       FIG. 3  is a front view of torsional vibration damper  100  shown in  FIG. 1 . 
       FIG. 4  is an exploded view of torsional vibration damper  100  shown in  FIG. 1 . The following is viewed in light of  FIGS. 1 through 4 . Torsional vibration damper  100 , includes: hub  102 ; idle damper stage  104 ; main damper stage  106 ; and friction control plate  108 . Friction control plate  108  is non-rotatably connected to hub  102  and is directly engaged with main damper stage  106 . Hub  102  is supported for rotation around axis of rotation AR. 
     By “non-rotatably connected” components, we mean that the components are connected so that whenever one of the components rotates, all the components rotate; and relative rotation between the components is precluded. Radial and/or axial movement of non-rotatably connected components with respect to each other is possible. Components connected by tabs, gears, teeth, or splines are considered as non-rotatably connected despite possible lash inherent in the connection. The input and output elements of a closed clutch are considered non-rotatably connected despite possible slip in the clutch. The input and output parts of a vibration damper, engaged with springs for the vibration damper, are not considered non-rotatably connected due to the compression and unwinding of the springs. In the example of  FIG. 1 , friction control plate  108  is displaceable parallel to axis AR. 
     By one component “directly engaged with” another component, we mean that the components are in direct contact, or that the components are in direct contact with one or more ancillary intermediate parts, for example, a cap fixed to an end of a spring, such that the components and the ancillary parts are mechanically solid. A possible function of the ancillary parts is to protect the components from wearing against each other. 
       FIG. 5  is a cross-sectional view generally along line  5 - 5  in  FIG. 3 . 
       FIG. 6  is a back view of torsional vibration damper  100  shown in  FIG. 1  with a damper plate removed. The following is viewed in light of  FIGS. 1 through 6 . In an example embodiment, idle damper stage  104  includes: damper flange  110  non-rotatably connected to hub  102 ; damper flange  111  non-rotatably connected to hub  102 ; and springs  112  directly engaged with damper flange  110  and with damper flange  111 . 
       FIG. 7  is a cross-sectional view generally along line  7 - 7  in  FIG. 3 . The following is viewed in light of  FIGS. 1 through 7 . In an example embodiment, main damper stage  106  includes: damper flange  114  directly engaged with springs  112 ; damper plate  116 ; and springs  118   
     directly engaged with damper flange  114  and with damper plate  116 . Friction control plate  108  is directly engaged with damper flange  114 . In the example of  FIG. 1 , friction control plate  108  is in contact with damper flange  114 . Springs  118  are radially off-set from springs  112 . In the example of  FIG. 1 , springs  118  are radially outward of springs  112 . Friction control plate  108  is free of contact with springs  112  and springs  118 . 
     One of damper plate  116  or hub  102 : is arranged to receive rotational torque RT 1  or RT 2  in circumferential direction CD 1  or opposite circumferential direction CD 2 , respectively, as an input to torsional vibration damper  100 ; and is supported for rotation about axis of rotation AR. The other of damper plate  116  or hub  102  is arranged to transmit torque RT 1  and RT 2  as an output of torsional vibration damper  100  and is supported for rotation about axis of rotation AR. 
     Torsional vibration damper  100  includes resilient element  120  and resilient element  122 . In the example of  FIG. 1 , element  120 : urges friction control plate  108  in axial direction AD, parallel to axis AR, into contact with main damper stage  106 . For example, element  120  urges friction control plate  108  into contact with damper flange  114 . 
     Element  122  urges hub  102  in direction AD and into direct engagement with main damper stage  106 . In an example embodiment, torsional vibration damper  100  includes resilient element  123 . Element  123  urges hub  102  in direction AD and into direct engagement with main damper stage  106 . Resilient elements  120 ,  122 , and  123  can be any resilient elements known in the art, including but not limited to diaphragm springs. 
     In an example embodiment, main damper stage  106  includes cage  124 . In an example embodiment, cage  124  includes: portion  126  non-rotatably connected to damper flange  114 ; and portion  128  non-rotatably connected to portion  126 . At least a portion of spring  112  is disposed within cage  124 . Resilient element  120  urges: damper flange  114  and cage  124  in direction AD; and cage  124  into direct engagement with plate  116 . In an example embodiment, resilient element  120  urges cage  124  into contact with plate  116 . 
     In an example embodiment, torsional vibration damper  100  includes friction ring  130  and friction ring  132 . Friction rings  130  and  132  are made of any friction material known in the art. Friction ring  130  is axially disposed between hub  102  and damper plate  116 . Friction ring  132  is axially disposed between hub  102  and resilient element  122 . In the example of  FIG. 1 , resilient elements  122  and  123 : urge hub  102  in axial direction AD to contact friction ring  130  with hub  102  and damper plate  116 ; and urge friction ring  132  into contact with hub  102 . 
     In an example embodiment, main damper stage  106  includes damper plate  134  non-rotatably connected to damper plate  116 , for example with bolts  136 . In an example embodiment, friction control plate  108  is disposed between damper flange  114  and damper plate  134  in direction AD. In an example embodiment, torsional vibration damper  100  includes support washer  138  axially disposed between resilient element  120  and friction control plate  108 . Resilient element  120  urges washer  138  in direction AD to contact friction control plate  108  and urge friction control plate in direction AD. 
     In an example embodiment, hypothetical line L, parallel to axis AR passes through in sequence: damper plate  116 ; portion  128 ; a spring  112 ; portion  126 ; damper flange  114 ; friction control plate  108 ; support washer  138 ; resilient element  120 ; resilient element  122 ; and damper plate  134 . In an example embodiment, any hypothetical line, orthogonal to axis AR and passing through friction control plate  108 , passes through hub  102 . For example, hypothetical line L 2 , orthogonal to axis AR, passes through friction control plate  108  passes and hub  102 . Line L 2  does not pass through damper flange  110 , damper flange  111 , damper flange  114 , damper plate  116 , or damper plate  134 . In the example of  FIG. 1 , an entirety of friction control plate  108  is located radially outward of hub  102 . 
       FIG. 8  is an isometric front view of hub  102  and friction control plate  108  of the torsional vibration damper  100  shown in  FIG. 1 . 
       FIG. 9  is an isometric view of friction control plate  108  in  FIG. 1 . The following is viewed in light of  FIGS. 1 through 9 . In an example embodiment: hub  102  includes radially outwardly extending splines, or teeth,  140  and slots  142 ; and friction control plate  108  includes radially inwardly extending splines, or teeth  144 , disposed in slots  142 , and slots  146  into which splines  140  are disposed. The interleaving of splines  140 , slots  146 , splines  144 , and slots  142  non-rotatably connects hub  102  and friction control plate  108 . 
     The discussion that follows is directed to operation of torsional vibration damper  100  with torque RT 1  applied to damper plate  116  as the input to torsional vibration damper  100 . It is understood that the discussion is applicable to operation of torsional vibration damper  100  with: torque RT 2  applied to damper plate  116  as an input to torsional vibration damper  100 ; torque RT 1  applied to hub  102  as an input to torsional vibration damper  100 ; and torque RT 2  applied to hub  102  as an input to torsional vibration damper  100 . 
     In an idle mode of torsional vibration damper  100 , torque RT 1 , for example from an internal combustion engine (not shown), is transmitted to damper plate  116  as an input to torsional vibration damper  100 . Torque RT 1  is less than threshold torque value TTV. Torque RT 1  is not great enough to compress springs  118 ; therefore damper plate  116 , springs  118 , and damper flange  114  act as a solid mechanical unit transmitting torque RT 1  to springs  112 . Vibration associated with torque RT 1  causes springs  112  to compress and unwind as springs  112  transmit torque RT 1  to hub  102 . The compression and unwinding of springs  112 : causes relative rotation between hub  102  and damper flange  114  and damper plate  116 ; and relative rotation between friction control plate  108  and damper flange  114 . 
     In the example of  FIG. 1  and for the idle mode, a total hysteresis is generated by: frictional contact between hub  102  and friction control plate  108 ; frictional contact among friction ring  130 , damper plate  116 , and hub  102 ; and frictional contact among hub  102 , friction ring  132 , resilient element  122 , and resilient element  123 . Since there is no relative rotation between damper flange  114  and damper plate  116 , there is no hysteresis generated by contact of cage  124  with damper plate  116 . The frictional contact of friction ring  130  and friction ring  132  with the other components noted above occurs on the respective sides of ring  130  and  132  offering the least resistance. 
     In a main mode of torsional vibration damper  100 , torque RT 1 , for example from an internal combustion engine (not shown), is transmitted to damper plate  116  as an input to torsional vibration damper  100 . Torque RT 1  is greater than or equal to threshold torque value TTV. Springs  118  compress and unwind in response to torque RT 1  to dampen vibration associated with torque RT 1 . Springs  118  transmit torque RT 1  to damper flange  114 , which in turn transmits torque RT 1  to springs  112 . Torque RT 1  is large enough to fully compress springs  112  such that damper flange  110 , springs  112 , and damper flanges  110  and  111  act as a solid mechanical unit transmitting torque RT 1  to hub  102 . As is known in the art, damper flange  114  contacts damper flanges  110  and  111  to prevent damage to springs  112  due to over-compression of springs  112 . 
     In the example of  FIG. 1  and for the main mode, resilient element  120  urges damper flange  114  in direction AD to contact damper plate  116  with cage  124 . Cage  124  is non-rotatably connected to damper flange  114  and the compression and unwinding of springs  118  causes relative rotation between damper flange  110 /cage  124  and damper plate  116 . In the example of  FIG. 1  and for the main mode, the total hysteresis is generated by: frictional contact between hub  102  and friction control plate  108 ; frictional contact among friction ring  130 , damper plate  116 , and hub  102 ; frictional contact among hub  102 , friction ring  132 , resilient element  122 , and resilient element  123 ; and frictional contact between cage  124  and damper plate  116 . 
     Torsional vibration damper  100  provides an increased idle mode hysteresis, which for example, in an application in which torsional vibration damper  100  is connected to an internal combustion engine, reduces sensed vibration associated with: engine start-up; engine shut-down; large input torque changes coming from an engine throttle change; and feedback from tires due to tractive force changes. 
     It will be appreciated that various of the above-disclosed and other features and functions, or alternatives thereof, may be desirably combined into many other different systems or applications. Various presently unforeseen or unanticipated alternatives, modifications, variations, or improvements therein may be subsequently made by those skilled in the art which are also intended to be encompassed by the following claims.