Abstract:
A centrifugal pendulum mechanism that includes a pendulum flange and pendulum masses which are fastened on both sides of the pendulum flange by a spacing bolt accommodated in a curved cutout of the pendulum flange to form a pair of pendulum masses, where the pair of pendulum masses is guided relative to the pendulum flange by the at least two rollers and can be pivoted restrictively because of a stop, where the rollers are accommodated in curved guide tracks in the pendulum masses and in complementary curved guide tracks in the pendulum flange and can be rolled, and at least two pairs of pendulum masses are arranged so as to be circumferentially adjacent to each other.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is filed under 35 U.S.C. §120 and §365(c) as a continuation of International Patent Application PCT/DE2011/000249, filed Mar. 7, 2011, which application claims priority from German Patent Application No. 10 2010 011 141.4, filed Mar. 11, 2010, which applications are incorporated herein by reference in their entireties. 
    
    
     FIELD OF THE INVENTION 
     The invention relates to a centrifugal pendulum mechanism. 
     BACKGROUND OF THE INVENTION 
     Such centrifugal pendulum mechanisms are, for example, known as torsional vibration dampers in terms of their effect, especially when used in drivetrains of motor vehicles, for example, as disclosed in German Patent Application No. 10 2004 011 830 A1. Pendulum masses are arranged with restricted pivoting on a pendulum flange that is driven by a drive unit, such as an internal combustion engine that is subject to torsional vibrations. A quenching effect of the torsional vibration arises as a result of the pendulum motion of the pendulum masses generated by the differing angular acceleration of the pendulum flange. 
     The pendulum flange can, for example, be designed to be integral with a component of a torsional vibration damper or a dual-mass flywheel, or it can be arranged on one of these components. Pendulum masses can be arranged on both sides of the pendulum flange, where axially opposing pendulum masses are connected to each other by means of spacing bolts. The spacing bolts move in cutouts that have a shape which is adapted to the pendulum motion of the pendulum masses. The pendulum masses are guided on the pendulum flange by means of guide tracks introduced there, for example, in the form of curved through-holes that are formed to be complementary with the guide tracks in the pendulum flange, where rolling elements roll in the guide tracks. The pendulum masses can be pivoted relative to the pendulum flange to a limited extent due to a stop. Depending on the nature of the pendulum mass deflection, the stops are formed by the spacing bolts impacting within the respective cutouts, or by circumferentially adjacent pendulum masses impacting each other. 
     While the centrifugal pendulum mechanism is operating or, for example, as the pendulum flange transitions from rotating to resting, the pendulum masses can impact each other or impact the spacing bolts in the cutout, which can lead to annoying noises in the centrifugal pendulum mechanism. 
     BRIEF SUMMARY OF THE INVENTION 
     The object of the invention is to improve the noise quality of a centrifugal pendulum mechanism while simultaneously optimizing the use of the installation space. 
     A centrifugal pendulum mechanism is correspondingly proposed that includes a pendulum flange and pendulum masses, which are fastened on both sides of the pendulum flange by means of a spacing bolt accommodated in a curved cutout of the pendulum flange to form a pair of pendulum masses, where the pair of pendulum masses is guided relative to the pendulum flange by means of at least two rollers and can be pivoted restrictively because of a stop, where the rollers are accommodated in curved guide tracks in the pendulum masses and in complementary curved guide tracks in the pendulum flange and can be rolled, and at least two pairs of pendulum masses are arranged so as to be circumferentially adjacent to each other. The stop for limiting the movement of the pair of pendulum masses is formed by the spacing bolt impacting the respective cutout, or by the impact of respective side surfaces of circumferentially neighboring pairs of pendulum masses, where damping means are formed on one of the components forming the stop. This dampens the impact and therefore reduces noise. 
     The impact of circumferentially neighboring pendulum masses can preferably be dampened by the previously acting impact of at least one roller in the guide path accommodating the roller. For example, overload protection is achieved for the damping means forming the stop for circumferentially neighboring pendulum masses, thus allowing the damping means to possess greater reliability and/or durability. 
     In one embodiment of the invention, the damping means, especially the damping means introduced on the stop between the spacing bolt and its cutout, or between circumferentially neighboring side surfaces of two pendulum masses, is designed as a composite element, at least including a first annular sub-element with elastic material properties, and a second also annular sub-element that preferably concentrically surrounds it, such as a sleeve, having material with high strength and/or rigidity in comparison to the first sub-element that is, for example, made of metal. 
     The composite element can be preferably designed such that the first sub-element is placed loosely on a spacing bolt, and the second sub-element is placed loosely on a spacing bolt. 
     In another embodiment of the invention, either the first sub-element can be integrally bonded, for example, by adhesion or vulcanization, to the second sub-element, or the first sub-element can be keyed to a spacing bolt. Additionally or alternatively, at least two components of the composite element are joined under initial tension. 
     The first sub-element of the composite element can also fill just part of the space between the spacing bolt and second sub-element so that the first sub-element can escape under an arising load, for example under impact. 
     The first sub-element and/or the second sub-element can also be designed from several parts. 
     The centrifugal pendulum mechanism can be arranged on a torsional vibration damper within a converter housing of a hydrodynamic torque converter, on a clutch device, such as a wet clutch or a dual clutch, or on a dual-mass flywheel. 
     In one embodiment of the invention, the damping means are integrally bonded or keyed with a component forming the stop. The damping means can be a damping layer that, for example, is glued to the respective component in the area of the stop or connected in some other manner. For example, the damping means can be clamped or caulked to the respective component. 
     In another embodiment of the invention, the damping means are attached to the axial section of the spacing bolt extending through the cutout. 
     In another embodiment of the invention, the damping means are attached to the surface of the edge of the cutout. The damping means are preferably attached to a peripheral or radial end area of the edge surface of the cutout. The damping means can also be attached in both peripheral end areas of the edge surface of the cutout. 
     In another embodiment of the invention, the damping means are arranged on the side surface of a pendulum mass that directly neighbors the circumferentially neighboring pendulum mass. 
     In another embodiment of the invention, the damping means are designed as elastic means, for example, as an elastomer, or thermoplastic, or plastic, or another material that is more elastic than steel. 
     In another embodiment of the invention, the damping means are designed as a single part with the component forming the stop. 
     Additional advantages and advantageous embodiments of the invention are found in the description and figures that, for the sake of clarity, are not reproduced true to scale. All of the explained features can be used in the indicated combination as well as in other combinations or by themselves without departing from the scope of the invention. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING 
       The nature and mode of operation of the present invention will now be more fully described in the following detailed description of the invention taken with the accompanying drawing figures, in which: 
         FIG. 1  is a side view of a torsional vibration damper with a centrifugal pendulum mechanism arranged thereupon in an embodiment of the invention; 
         FIG. 2   a  is a side view of a centrifugal pendulum mechanism in an embodiment of the invention; 
         FIG. 2   b  is a three-dimensional detailed view of section A of  FIG. 2   a;    
         FIG. 3   a  is a side view of a centrifugal pendulum mechanism in another embodiment of the invention; 
         FIG. 3   b  is a three-dimensional detailed view of section B from  FIG. 3   a;    
         FIG. 4   a  is a side view of a centrifugal pendulum mechanism in another embodiment of the invention; 
         FIG. 4   b  is a three-dimensional detailed view of section C of  FIG. 4   a;    
         FIG. 5   a  is a three-dimensional view of damping means in an embodiment of the invention; 
         FIG. 5   b  is a cross-sectional view of the damping means of  FIG. 5   a;    
         FIG. 6  is a cross-sectional view of damping means in another embodiment of the invention; and, 
         FIG. 7  is a partial section of a side view of a centrifugal pendulum mechanism in another embodiment of the invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     At the outset, it should be appreciated that like drawing numbers on different drawing views identify identical, or functionally similar, structural elements of the invention. While the present invention is described with respect to what is presently considered to be the preferred aspects, it is to be understood that the invention as claimed is not limited to the disclosed aspects. 
     Furthermore, it is understood that this invention 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 invention, which is limited only by the appended claims. 
     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 invention belongs. Although any methods, devices or materials similar or equivalent to those described herein can be used in the practice or testing of the invention, the preferred methods, devices, and materials are now described. 
       FIG. 1  shows a side view of torsional vibration damper  10  with centrifugal pendulum mechanism  12  arranged thereupon. Disc carrier  16  functioning as a clutch output of a clutch device is arranged on damper part  14  of torsional vibration damper  10  designed as a parallel damper. The clutch device can, for example, be designed as a torque converter lockup clutch or as a wet clutch. Torsional vibration damper  10  is effectively connected between the clutch output and drive hub  18 , where drive hub  18  can be connected via teeth  20  to a transmission input shaft of a transmission in a drivetrain of a motor vehicle. 
     Damper input part  14  is centered radially to the inside on drive hub  18 , and is accommodated in an axially secure manner, and surrounds first energy storage elements  22  radially to the outside such as bow springs that effectively connect damper input part  14  to intermediate damper part  24 , where intermediate damper part  24  is slightly rotatable relative to damper input part  14 . Intermediate damper part  24  in turn is slightly rotatable relative to damper output part  28  under the effect of second energy storage elements  26  such as pressure springs that lie radially further to the inside. Damper output part  28  is non-rotatably connected to drive hub  18 , for example, by means of a weld connection. 
     Intermediate damper part  24  includes of two axially spaced disc parts  30 ,  32  that axially enclose damper output part  28 . One disc part  32  is extended radially to the outside to form pendulum flange  34 . Pendulum flange  34  is an integral component of disc part  32 , but it can also be fastened as a separate component thereto, for example, by being riveted, screwed or welded. Disc part  32  is non-rotatably connected radially inside with turbine hub  36 , and turbine hub  36  is used to connect a turbine wheel of a hydrodynamic torque converter. Turbine hub  36  is centered on drive hub  18  and is rotatably arranged relative thereto. 
     Pendulum flange  34  accommodates two axially opposing pendulum masses  38  in a section radially to the outside, where pendulum masses  38  are connected to each other by means of spacing bolt  40 , and spacing bolt  40  extends through section  42  in pendulum flange  34 . 
       FIG. 2   a  shows a side view of centrifugal pendulum mechanism  12  in an embodiment of the invention, where the top pendulum mass was left out of the drawing to illustrate the area underneath. Centrifugal pendulum mechanism  12  is arranged on disc part  32  of the intermediate damper part of the torsional vibration damper, where the radial extension of disc part  32  forms pendulum flange  34  for accommodating pendulum masses  38  arranged on both sides of pendulum flange  34 , where two pendulum masses  38  each are arranged axially on both sides of pendulum flange  34  and are connected to each other by means of spacing bolts  40  to a pair of pendulum masses. Spacing bolts  40  extend through sections  44  in pendulum flange  34 , where the sections  44  are designed in the shape of an arc such that they enable a pendulum movement of pendulum masses  38  relative to pendulum flange  34  along their pendulum path. Pendulum masses  38  are guided over rollers  46  on pendulum flange  34 , and rollers  46  can roll in kidney-shaped guide paths  48  on pendulum masses  38  and in complementary kidney-shaped guide paths  50  on pendulum flange  34 . 
     The movement of pendulum masses  38  relative to pendulum flange  34  is limited by stops, where the stops, depending on the nature of the deflection of pendulum mass  38 , are formed by the impact of spacing bolts  40  in respective cutouts  44 , or by the impact of respective side surfaces  52  of circumferentially neighboring pendulum masses  38  against each other.  FIG. 2   b  shows section A of  FIG. 2   a  in a three-dimensional view. In cutouts  44 , that is, on edge surface  54  of cutouts  44 , damping means  56  are attached in the form of a damping layer which, for example, can be integrally bonded or keyed to edge surface  54 . Preferably, damping means  56  are attached in a circumferential or radial end area  58  of edge surface  54 , ideally where spacing bolts  40  can strike edge surface  54  instead of gliding along it. 
       FIG. 3   a  shows a side view of centrifugal pendulum mechanism  12  in another embodiment of the invention, where the top pendulum mass was left out of the drawing to illustrate the area underneath. As shown in  FIG. 3   b  in greater detail with reference to three-dimensional section B of  FIG. 3   a : pendulum  38 A includes side surface  52 A; pendulum  38 B includes side surface  52 B facing side surface  52 A in circumferential direction CD 1 ; side surface  52 A includes indentation  55  forming a keyed fit in side surface  52 A; buffer element  57 A is disposed in indentation  55  and extends from side surface  52 A in circumferential direction CD 2 ; buffer element  57 B extends from side surface  52 B in circumferential direction CD 1 ; side surfaces  52 A and  52 B have extents E 1  and E 2 , respectively in radial direction RD orthogonal to axis of rotation AR for mechanism  12 ; buffer elements  57 A and  57 B have extents E 3  and E 4 , respectively, in direction RD; extent E 1  is greater than extent E 3 ; and extent E 2  is greater than extent E 4 . 
       FIG. 4   a  shows a side view of centrifugal pendulum mechanism  12  in another embodiment of the invention.  FIG. 4   b  shows the three-dimensional view of section C of  FIG. 4   a . Spacing bolts  40  have damping means  56  in the form of a damping sleeve on their rolling surface which can dampen the impact of spacing bolts  40  in cutouts  44 . 
     Damping means  56  are shown in  FIG. 5   a  and  FIG. 5   b  in an embodiment of the invention. Damping means  56  are attached to spacing bolt  40 , for example, in a keyed fit, or also with a certain amount of play between damping means  56  and spacing bolt  40 . Furthermore, damping means  56  are designed as a composite element consisting of first, annular sub-element  60  preferably with elastic material properties, and a second also annular sub-element  62  that preferably concentrically surrounds it, such as a sleeve, especially having a material with greater strength and/or rigidity in comparison to first sub-element  60 . Second sub-element  62  can, for example, be made of metal. 
       FIG. 6  shows a cross-sectional view of damping means  56  in another embodiment of the invention. The damping means are designed as a composite element consisting of first sub-element  60  and second sub-element  62 , where first sub-element  60  is designed as a toroidal element, such as a sealing ring, and preferably as an O-ring. First sub-element  60  is designed to be more elastic than second sub-element  62  and also not as rigid and/or strong. 
       FIG. 7  shows a section of a side view of centrifugal pendulum mechanism  12  in another embodiment of the invention. Damping means  56  are formed on side surfaces  52  of circumferentially neighboring pendulum masses  38  as a single part with respective pendulum mass  38 . Cutouts  64  or slots extending radially are introduced in pendulum mass  38  to give pendulum mass  38  elastic material properties to form damping means  56 . 
     In one embodiment, two radially extending cutouts  64  are provided; however, a plurality of cutouts can be formed that can not only extend radially but can also alternatively or additionally have windings and be designed in a serpentine fashion. The cutouts can also be designed to run axially and/or radially and/or have a combination of a radial and an axial path. The cutouts can preferably be created by stamping and/or cutting, such as laser cutting. 
     Thus, it is seen that the objects of the present invention are efficiently obtained, although modifications and changes to the invention should be readily apparent to those having ordinary skill in the art, which modifications are intended to be within the spirit and scope of the invention as claimed. It also is understood that the foregoing description is illustrative of the present invention and should not be considered as limiting. Therefore, other embodiments of the present invention are possible without departing from the spirit and scope of the present invention. 
     LIST OF REFERENCE NUMBERS 
     
         
           10  Torsional vibration damper 
           12  Centrifugal pendulum mechanism 
           14  Damper input part 
           16  Disc carrier 
           18  Drive hub 
           20  Gearing 
           22  Energy storage element 
           24  Intermediate damper part 
           26  Energy storage element 
           28  Damper output part 
           30  Disc part 
           32  Disc part 
           34  Pendulum flange 
           36  Turbine hub 
           38  Pendulum mass 
           40  Spacing bolts 
           42  Cut out 
           44  Cut out 
           46  Rollers 
           48  Guide path 
           50  Guide path 
           52  Side surface 
           54  Edge surface 
           55  Indentation 
           56  Damping means 
           57  Buffer element 
           58  End area 
           60  Sub-element 
           62  Sub-element 
           64  Cut out