Abstract:
A centrifugal pendulum mechanism having a pendulum flange and pendulum masses, which are fastened by bolts on both sides of the pendulum flange and are guided by rollers and can be pivoted slightly relative to the pendulum flange. At least two pendulum masses are arranged on the pendulum flange so as to be circumferentially adjacent. One pendulum mass has a lateral surface that faces the adjacent pendulum mass, and the contour of the lateral surface is at a substantially acute angle.

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/DE2011/000172, filed Feb. 21, 2011, which application claims priority from German Patent Application No. 10 2010 011 140.6, 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, from 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 bolts. The bolts move in openings that have a shape, which is adapted to the pendulum motion of the pendulum masses. The pendulum masses are guided in the pendulum flange by means of cutouts introduced there that are complementary with the cutouts in the pendulum flange, and rollers roll in the cutouts. While the centrifugal pendulum device is operating, the pendulum masses can impact each other while the pendulum flange is rotating. When the pendulum flange switches from rotating to stationary, one pendulum mass can strongly impact the circumferentially neighboring pendulum mass, which can lead to annoying noises in the centrifugal pendulum device. 
     BRIEF SUMMARY OF THE INVENTION 
     The object of the invention is to improve the noise quality of a centrifugal pendulum device while optimally utilizing the installation space, preferably by damping or avoiding the impact between circumferentially adjacent pendulum masses. 
     Accordingly, a centrifugal pendulum mechanism is proposed having a pendulum flange and pendulum masses, which are fastened by means of bolts on both sides of the pendulum flange and are guided by means of rollers and can be pivoted slightly relative to the pendulum flange, where at least two pendulum masses are arranged on the pendulum flange so as to be circumferentially adjacent, and one pendulum mass has a lateral surface that faces the adjacent pendulum mass, and the contour of the lateral surface is at a substantially acute angle. When the pendulum masses contact each other while the pendulum flange is rotating and/or when the pendulum flange transitions from rotating to stationary, this can cause one pendulum mass to smoothly glide off the circumferentially adjacent pendulum mass. The contour of the lateral surface can be designed such that two neighboring pendulum masses can execute a very expansive pendulum movement relative to the pendulum flange while the centrifugal pendulum mechanism is operating and not contact the pendulum masses. 
     In one embodiment of the invention, the contours of two facing lateral surfaces of adjacent pendulum masses are at an acute angle. The contour of the lateral surface of a pendulum mass is preferably designed to symmetrically mirror the contour of the neighboring lateral surface of the adjacent pendulum mass with reference to a radial line. The edge of the contour can be rounded if two adjacent pendulum masses first contact each other with the edge under certain circumstances. However, the contour can be designed so that edge-to-edge contact is highly improbable. 
     In another embodiment of the invention, two lateral surfaces of a pendulum mass are connected to each other radially to the outside by an outer surface and radially to the inside by an inner surface, where the acute angle of the contour of the lateral surface is enclosed between the outer surface or the inner surface and the lateral surface. 
     In another embodiment of the invention, two lateral surfaces of a pendulum mass are connected to each other radially to the outside by an outer surface and radially to the inside by an inner surface, where the acute angle of the contour of the lateral surface is formed within the lateral surface. The acute angle of the contour of the lateral surface is preferably formed substantially radially in the middle of the lateral surface. 
     In yet another embodiment of the invention, the two lateral surfaces of a pendulum mass each have an acute angle in their contour, where one contour is designed to symmetrically mirror the other contour relative to a radial line. One contour can also be designed to be asymmetrical to the other contour of a common pendulum mass relative to a radial line. 
     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 DRAWINGS 
       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 centrifugal pendulum mechanism arranged on a component of a torsional vibration damper in a special embodiment of the invention; 
         FIG. 2  is a three-dimensional detailed view of section A of  FIG. 1 ; and 
         FIG. 3  is a detailed view of section B of  FIG. 1 . 
     
    
    
     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 a component of torsional vibration damper  10 .  FIG. 2  is a three-dimensional detailed view of section A of  FIG. 1 .  FIG. 3  is a detailed view of section B of  FIG. 1 . This component is designed as a damper flange that has window cutouts  12  to accommodate energy storage elements such as helical springs in an area radially to the inside. The damper flange also forms pendulum flange  22  of centrifugal pendulum mechanism  20 , where two pendulum masses  24  are arranged axially on each side of pendulum flange  22  and are connected to each other by means of bolts  26  to a pair of pendulum masses. Bolts  26  extend through cutouts  28  in pendulum flange  22 , where cutouts  28  are designed in the shape of an arc such that they enable a pendulum movement of pendulum masses  24  relative to pendulum flange  22 . Pendulum masses  24  are guided on rolling elements  30  relative to pendulum flange  22 , and rolling elements  30  can roll in cutouts  32  in pendulum masses  24  and in complementary cutouts  34  in pendulum flange  22 . Pendulum mass  24 A is connected to pendulum flange  22  by bolts  26 A and  26 B. Pendulum mass  24 B is connected to pendulum flange  22  by bolts  26 C and  26 D. Rolling elements  30 A and  30 B guide pendulum mass  24 A. Rolling elements  30 C and  30 D guide pendulum mass  24 B. Rolling elements  30 A and  30 B are circumferentially between bolts  26 A and  26 B. Rolling elements  30 C and  30 D are circumferentially between bolts  26 C and  26 D. Bolts  26 A and  26 C are located in C-shaped cutout  28 A. 
     As shown in greater detail in  FIG. 2 , pendulum mass  24  has outer surface  36  radially to the outside and inner surface  38  radially to the inside. The circumferential sides of pendulum mass  24  are bordered by lateral surfaces  40 . Two lateral surfaces  40  of pendulum mass  24  and a pendulum mass circumferentially adjacent thereto face each other. The contour of lateral surface  40  has acute angle  42  substantially in the center relative to the radial extension of lateral surface  40 , as well as the neighboring lateral surfaces of the adjacent pendulum mass. The contours of the lateral surfaces of each adjacent pendulum mass as well as the contours of the two lateral surfaces of one pendulum mass are designed to symmetrically mirror each other with reference to radial lines, such as R 1  or R 2 . In a first position, as shown in  FIG. 2 , radial Radial line R 1 , orthogonal to axis of rotation AR, passes through respective surfaces  40 A and  40 B for adjacent masses  24 A and  24 B, respectively. Circumferential line L passes through surfaces  40 A and  40 B for adjacent masses  24 A and  24 B, respectively. In the first position, as shown in  FIG. 3 , radial line R 2  passes between respective surfaces  40 C and  40 D for adjacent masses  24 A and  24 C, respectively. Acute angles  42 A and  42 B, for surfaces  40 A and  40 B, respectively, also are with respect to line L. Axis of rotation AR passes through central opening  44 . Pendulum mass  24 A is adjacent pendulum mass  24 C in circumferential direction C and pendulum mass  24 D is adjacent to pendulum mass  24 C in direction C. In the first position, surfaces  40 A and  40 B are in contact and surfaces  40 C and  40 D are not in contact. 
     The two facing lateral surfaces can be at a certain fixed or changing distance from each other while centrifugal pendulum mechanism  20  is operating, where under certain circumstances, the lateral surfaces of the two pendulum masses can contact each other. The special, pointed design of the contour of the lateral surface can keep the pendulum masses from impacting each other since the pendulum masses can glide past each other in sections due to the contour of the pendulum mass acting as a guide. 
     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  Window cutouts 
           20  Centrifugal pendulum mechanism 
           22  Pendulum flange 
           24  Pendulum masses 
           26  Bolt 
           28  Cutouts 
           30  Rolling element 
           32  Cutouts 
           34  Cutouts 
           36  Outer surface 
           38  Inner surface 
           40  Lateral surface 
           42  Acute angle 
           44  Central opening