Abstract:
The invention relates to a centrifugal pendulum mechanism, having at least one pendulum mass support and at least one pendulum mass arranged thereon, which pendulum mass can be moved to a limited extent radially relative to the pendulum mass support by means of at least one rolling element inside raceways formed by recesses in the pendulum mass support and the pendulum mass and in the circumferential direction, the rolling element having guiding means formed in the gap between the individual pendulum mass and the pendulum mass support. The invention includes means for reducing the gap size between the pendulum mass and the pendulum mass support in an at least spatially limited manner are provided outside the raceways for the rolling element and outside the range of the intermediate space between the pendulum mass and the pendulum mass support that can be converted by the guiding means.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is filed under 35 U.S.C. §120 and §365(c) as a continuation of International Patent Application No. PCT/DE2010/001453, filed Dec. 13, 2010, which application claims priority from German Patent Application No. 10 2009 059 755.7, filed Dec. 21, 2009, and German Patent Application No. 10 2010 021 410.8, filed May 25, 2010, which applications are incorporated herein by reference in their entireties. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The invention relates to a centrifugal pendulum mechanism having at least one pendulum mass support and at least one pendulum mass arranged thereon, which pendulum mass is movable by means of at least one rolling element to a limited extent in a radial direction and in a circumferential direction relative to the pendulum mass support inside tracks formed by recesses in the pendulum mass support. 
       BACKGROUND OF THE INVENTION 
       [0003]    In drive trains, absorbers that are adaptable to a wide range of rotational speeds, preferably to the entire speed range of the driving engine, are used to dampen vibrations. They are capable of absorbing torsional vibration over a wide range of speeds, ideally over the entire speed range of the driving engine due to the fact that they are designed and arranged in a way to ensure that their natural frequency is proportional to the rotational speed. Such absorbers operate according to the principle of a centrifugal pendulum in a centrifugal-force field. They include a pendulum mass support that is rotatable about an axis of rotation and inert or pendulum masses swingingly arranged about the axis of rotation of the pendulum mass support. When a rotary movement is introduced, the individual pendulum masses strive to circulate about the axis of rotation at a maximum possible distance. The torsional vibrations result in a relative swinging movement of the pendulum masses. Different systems are known in the art: systems in which the pendulum masses carry out a purely translatory movement on a circular path of movement relative to the axis of introduction of the rotary movement and systems in which the path of movement has a radius of curvature that changes at least in sections as the pendulum masses are increasingly deflected out of their central position. 
         [0004]    Published German Patent Application No. 10 2006 028 556 A1 discloses a centrifugal pendulum mechanism of this general type in a drive train of a motor vehicle. The mechanism includes a rotatable pendulum mass support and pendulum masses that are arranged thereon in opposing pairs. The pendulum masses are movable to a limited extent relative to the pendulum mass support by means of rolling elements. For this purpose, the rolling elements are movable to a limited extent in tracks formed by recesses in the pendulum mass support and in the pendulum masses. For example, the recesses are formed as continuous longitudinal holes with a kidney-shaped curvature. Between the pendulum mass support and the respective adjacent pendulum mass, the rolling elements have a guide means provided in the region between pendulum mass and pendulum mass support, for example, in the shape of a collar or shoulder for guiding the pendulum mass as it moves relative to the pendulum mass support and for preventing the pendulum mass from hitting the pendulum mass support. Due to the axial width of such guide means, which are formed to be integral with the rolling element or are connected to the latter so as to be fixed against rotation relative thereto, a minimum distance between the facing surfaces of pendulum mass and pendulum mass support is generated. This distance cannot be reduced at will without impeding the rolling motion. The resultant spaced distance between the pendulum mass support and an individual pendulum mass surface facing the pendulum mass support is comparatively wide. Thus, the pendulum mass may tilt relative to the pendulum mass support, causing a considerable problem in particular at low speeds with inherently low centrifugal forces. If this happens, the functioning of the centrifugal force pendulum is compromised in this speed range and is not reliably reproducible for a repeat case. The tilting may additionally cause damage to the individual components and their connections as well as to the swinging support of the pendulum mass on the pendulum mass support. 
       BRIEF SUMMARY OF THE INVENTION 
       [0005]    An object of the invention is to provide an improved centrifugal pendulum mechanism that reduces the tilting tendency of the individual pendulum masses relative to the pendulum mass support and provides enhanced stability. 
         [0006]    In one embodiment, a centrifugal pendulum mechanism includes at least one pendulum mass support, at least one pendulum mass arranged thereon, at least one rolling element extending through the pendulum mass and through the pendulum mass support to receive the pendulum mass inside tracks formed by recesses in the pendulum mass support and in the pendulum mass in a way for the pendulum mass to be movable to a limited extent in the radial direction and in the circumferential direction relative to the pendulum mass support, the rolling element including a guide means provided in the gap between pendulum mass and pendulum mass support, where means for reducing a gap distance between pendulum mass and pendulum mass support at least in a locally limited way are provided outside the tracks for the rolling element and outside the region coverable by the guide means in the gap between pendulum mass and pendulum mass support upon a rolling movement of the rolling element. 
         [0007]    The gap between a single pendulum mass and the pendulum mass support is understood to be the space that extends in the axial direction and is formed in the radial direction and in the circumferential direction between a pendulum mass and the pendulum mass support. The position of the gap varies as a function of the position of the individual pendulum mass upon its deflection under the influence of the centrifugal force. The width of the gap, which defines the axial distance between pendulum mass and pendulum mass support, is measured between the respective facing surfaces of the pendulum mass and of the pendulum mass support. The width of the gap may be constant across the entire extension of an individual pendulum mass front face facing towards the pendulum mass support. Alternatively, the width of the gap may vary in the direction of extension in the radial direction and/or in the circumferential direction. 
         [0008]    A reduction in the sense of the invention is understood to be a shortening of the axial width of the gap; yet despite the shortening, a minimum gap is always maintained to avoid negative effects on the functioning of the centrifugal pendulum due to friction between pendulum mass and pendulum mass support upon deflection due to the influence of centrifugal forces. That is to say that the mans are designed and arranged in a way to ensure that even in an unloaded condition of the centrifugal pendulum, the individual pendulum mass and the pendulum mass support do not contact each other. The minimum distance is selected as a function of the field of use of such a centrifugal pendulum mechanism. 
         [0009]    The means provided in accordance with the invention at least locally attain a reduction of the gap distance between pendulum mass and pendulum mass support, thus reducing the theoretically possible tilting angle, avoiding undesired tilting of the individual pendulum masses, for example, at low rotational speeds, and increasing the stability of the centrifugal pendulum on the whole. 
         [0010]    In terms of the arrangement and design of the means for an at least locally limited reduction of the gap distance, two basic embodiments can be distinguished. The first basic embodiment includes at least one or more means of this type, each of which is arranged and effective only in at least one part of the gap between pendulum mass and pendulum mass support. An advantage of this embodiment is that a gap reduction is attainable in a specific location. The number and/or geometry and/or dimensions and/or arrangement of the means in the gap are selected as a function of the geometry and dimensions of the centrifugal pendulum, for example, of the individual pendulum mass. As the means are smaller than the individual pendulum mass in terms of their dimensions, standardized spacer elements that are integratable into the means for spacing apart the pendulum mass and the pendulum mass support can preferably be used independently of their geometry. 
         [0011]    In a first embodiment, the means for reducing the gap distance between pendulum mass and pendulum mass support at least in a locally limited way are arranged in a way to be symmetrical relative to the pendulum mass. 
         [0012]    In a second embodiment, the means for reducing the gap distance at least in a locally limited way are formed to extend over the entire extension of the gap in the radial direction and in the circumferential direction outside the tracks for the rolling element and the region that is passable by the guide means between the pendulum mass and the pendulum mass support upon a rolling movement of the rolling element. An advantage of this embodiment is that a constant gap distance is set between pendulum mass and pendulum mass support. 
         [0013]    In terms of the association of the means to the individual gap-forming components, there are basically three options. In a first option, the means for reducing the gap distance at least in a locally limited way are associated with the pendulum mass and are preferably coupled to or formed on the pendulum mass. An advantage of this association is that it is a simple way of increasing the mass of the pendulum. An association with the pendulum mass permits the use of standardized pendulum mass supports and avoids modifications to the latter. 
         [0014]    In a second option, the means for reducing the gap distance at least in a locally limited way are associated with the pendulum mass support and are preferably coupled to or formed on the latter. This embodiment permits taking into account the requirement of such means for reducing the gap width at least in a locally limited way when the pendulum mass support is manufactured. Depending on the type and design of these means, they can be integrated into the pendulum mass support in one process step. 
         [0015]    The third option is a combination of the two aforementioned options. This option may partly combine the advantages of the two options. 
         [0016]    In terms of the design of the individual means for reducing the gap distance at least in a locally limited way, two alternatives can be distinguished. One alternative envisages the use of separate add-on elements. A second alternative envisages forming the means as an integral part of at least one of the components pendulum mass and/or pendulum mass support. 
         [0017]    In the first alternative, the means for reducing the gap width at least in a locally limited way are retroactively integratable into existing centrifugal pendulum devices, i.e., they can be retrofit. Depending on the selected design, add-on elements in the shape of standardized elements may be used in a preferable way. Such standardized elements are easy to be kept in stock and are easy to connect at least indirectly to the pendulum mass or to the pendulum mass support. 
         [0018]    In one sub-feature of the first alternative, the means include at least one add-on element in the form of a washer, which may be a standardized component. Such add-on elements are easy to arrange between pendulum mass and pendulum mass support without requiring modifications. The washers may be connected to the pendulum mass support or to an individual pendulum mass. Alternatively, if they are sufficiently fixed in position, for example, using axial stop surfaces that are present in any case on a spacer bolt, then they may be loosely inserted and held in the gap by the connection between the pendulum mass and the axial end region of the spacer bolt. 
         [0019]    In another sub-feature, the means include at least one add-on element that forms at least one protrusion projecting into the gap. The add-on element may be embodied as one of the components listed below: ball, cylinder pin, bolt, shell-shaped element, rivet head, etc. This list is not final. Any add-on element may be used that is easy to connect to the pendulum mass support or to an individual pendulum mass and interacts with the former or the latter to form a protrusion extending into the gap. 
         [0020]    In yet another sub-feature, an add-on element, for example, a disc-shaped element, is used that extends over the entire surface of the individual pendulum mass on the front face facing the pendulum mass support with the exception of the tracks and an area around the tracks that is coverable by the individual guide means. This embodiment includes a constant gap distance in the entire pendulum mass area in the un-deflected state. 
         [0021]    In all of the aforementioned embodiments, the add-on elements are connected to the respective components (pendulum mass or pendulum mass support) in a force-fitting, form-fitting, or material-locking way. 
         [0022]    If the individual pendulum mass is coupled to the pendulum mass support via a spacer element or if the centrifugal pendulum mechanism includes the fact that two respective pendulum masses are arranged on a pendulum mass support in opposing pairs and are coupled to each other and defined in their positions relative to each other by spacer bolts, such a spacer element, which is provided in any case, or a spacer bolt may be used preferably to fix the means for reducing the gap distance, and thus, combining two functions. 
         [0023]    In the second alternative, the means for reducing the gap distance at least in a locally limited way are formed integrally with the pendulum mass and/or with the pendulum mass support. They may be created in various ways. 
         [0024]    In the first embodiment, locally limited protrusions extending in the axial direction may be created to reduce the gap distance by suitable shaping or machining of the surface of the pendulum mass and/or of the pendulum mass support. In one sub-feature, at least one area may be embodied as a coined element formed at least in sections on the pendulum mass and/or on the pendulum mass support. The coined elements form protrusions directed into the gap. An area around the track of the pendulum mass and/or of the pendulum mass support is coined on at least in sections and the guide means is receivable in the recess formed by the coined element. Thus, the pendulum mass may be arranged closer to the pendulum mass support and the installation space that the centrifugal pendulum mechanism requires is reduced. 
         [0025]    In another sub-feature, the means for reducing the gap distance at least in a locally limited way are formed by at least one semi-piercing on a pendulum mass and/or on the pendulum mass support. Semi-piercings are created by a displacement of material under pressure and corresponding deformation. The semi-piercings are to be arranged in such a way that the resultant protrusions formed on the opposing front faces of pendulum mass and/or pendulum mass support due to the displacement of material are located outside the tracks for the rolling element and outside the area passable by the guide means. The creation of semi-piercings permits a targeted and simple arrangement of axial protrusions in the desired way to reduce the distance. 
         [0026]    A centrifugal pendulum mechanism that is designed in accordance with the invention is usable, for example, in a torsional vibration damper in a drive train of a motor vehicle. The torsional vibration damper includes an input part, an output part rotatable relative to the input part to a limited extent against the action of energy storage elements, and one or more damper stages. The centrifugal pendulum device may be arranged on a disc part of the damper stage, for example, on the input part, on a potential intermediate part, or on the output part. 
         [0027]    The centrifugal pendulum mechanism of the invention is also usable in a torque converter with a torsional vibration damper with a centrifugal pendulum mechanism arranged thereon. The torsional vibration damper that includes the centrifugal pendulum mechanism may be arranged inside a housing of the torque converter. 
         [0028]    Further advantageous fields of use are dual mass flywheels, double clutches, wet clutches, or dry clutches. 
     
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING 
         [0029]    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: 
           [0030]      FIG. 1  is a front view of a section of a centrifugal pendulum mechanism; 
           [0031]      FIG. 2   a  is a cross-sectional view taken along a line A-A of  FIG. 1  of a prior art embodiment of a centrifugal pendulum mechanism; 
           [0032]      FIG. 2   b  is a cross-sectional view taken along a line B-B of  FIG. 1  of a prior art embodiment of a centrifugal pendulum mechanism; 
           [0033]      FIG. 2   c  is a cross-sectional view taken along a line C-C of  FIG. 1  of a prior art embodiment of a centrifugal pendulum mechanism; 
           [0034]      FIG. 3   a  is a view of section A-A of  FIG. 1  of a first embodiment of a first alternative of a second basic embodiment of a centrifugal pendulum mechanism of the invention; 
           [0035]      FIG. 3   b  is a view of section B-B of  FIG. 1  of a first embodiment of a first alternative of a second basic embodiment of a centrifugal pendulum mechanism of the invention; 
           [0036]      FIG. 3   c  is a view of section C-C of  FIG. 1  of a first embodiment of a first alternative of a second basic embodiment of a centrifugal pendulum mechanism of the invention; 
           [0037]      FIG. 4   a  is a view of section A-A of  FIG. 1  of an embodiment of a first alternative of a first basic embodiment of a centrifugal pendulum mechanism of the invention; 
           [0038]      FIG. 4   b  is view of section B-B of  FIG. 1  of an embodiment of a first alternative of a first basic embodiment of a centrifugal pendulum mechanism of the invention; 
           [0039]      FIG. 4   c  is a view of section C-C of  FIG. 1  of an embodiment of a first alternative of a first basic embodiment of a centrifugal pendulum mechanism of the invention; 
           [0040]      FIG. 5   a  illustrates a development of a first alternative of a first basic embodiment of  FIG. 4   a;    
           [0041]      FIG. 5   b  is a view B-B of  FIG. 1  for a further development of a first alternative of a first basic embodiment; 
           [0042]      FIG. 5   c  illustrates a further development of a first alternative of a first basic embodiment of  FIG. 4   c;    
           [0043]      FIG. 6  is a view in accordance with section A-A of  FIG. 1  of a second embodiment of a first alternative of a first basic embodiment of a centrifugal pendulum mechanism of the invention; 
           [0044]      FIG. 7  is a view of section B-B of  FIG. 1  of a third embodiment of a first alternative of a first basic embodiment of a centrifugal pendulum mechanism of the invention; 
           [0045]      FIG. 8   a  is a view of section A-A of  FIG. 1  of a first embodiment of a second alternative of a first basic embodiment of a centrifugal pendulum mechanism of the invention; 
           [0046]      FIG. 8   b  is a view of section B-B of  FIG. 1  of a first embodiment of a second alternative of a first basic embodiment of a centrifugal pendulum mechanism of the invention; 
           [0047]      FIG. 8   c  is a view of section C-C of  FIG. 1  of a first embodiment of a second alternative of a first basic embodiment of a centrifugal pendulum mechanism of the invention; 
           [0048]      FIG. 9   a  is a view of section A-A of  FIG. 1  of a further embodiment of a second alternative of a first basic embodiment of a centrifugal pendulum mechanism of the invention; 
           [0049]      FIG. 9   b  is a view of section B-B of  FIG. 1  of a further embodiment of a second alternative of a first basic embodiment of a centrifugal pendulum mechanism of the invention; 
           [0050]      FIG. 9   c  is a view of section C-C of  FIG. 1  of a further embodiment of a second alternative of a first basic embodiment of a centrifugal pendulum mechanism of the invention; and, 
           [0051]      FIG. 10  is a view of section A-A in  FIG. 1  of a further embodiment of a second alternative of a first basic embodiment of a centrifugal pendulum mechanism of the invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0052]    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. 
         [0053]    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. 
         [0054]    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. 
         [0055]      FIG. 1  is a simplified diagrammatic front view of a section of a speed-adaptive absorber designed as centrifugal pendulum mechanism  1  in accordance with the invention. Centrifugal pendulum mechanism  1  preferably includes multiple inert masses that act as pendulum masses  2  and are swingingly supported on rotatable pendulum mass support  3  so as to be movable relative thereto. Pendulum mass support  3  is preferably shaped like an annular disc. Individual pendulum masses  2  are circumferentially arranged thereon about axis of rotation R at regular intervals. In the illustrated section, only one pendulum mass  2 A of pendulum mass unit  2  is shown. Axis of rotation R is only indicated for a better understanding and is not drawn to scale. In one embodiment, the support of individual pendulum masses  2 A,  2 B on pendulum mass support  3  is described for the individual alternatives of the two basic embodiments in the sectional views A-A, B-B, C-C of  FIGS. 3 to 10 . The sectional views A-A, B-B, C-C of  FIGS. 2   a  to  2   c  illustrate the tilting problem of pendulum masses  2 A′,  2 B′ relative to pendulum mass support  3 ′ in prior art centrifugal pendulum device  1 ′. In these Figures, a “′” is added to the reference numerals of the individual components. 
         [0056]    In all these embodiments, pendulum masses  2 A,  2 B are arranged in respective opposing pairs on both sides of front faces  4 . 1  and  4 . 2  of pendulum mass support  3 . Individual pendulum masses  2 A,  2 B are of an essentially circular ring segment shape. Pendulum masses  2 A,  2 B that oppose each other on front faces  4 . 1 ,  4 . 2  of the pendulum mass support are connected to each other to form single pendulum mass unit  2 . Here, the connections are indicated by reference numerals  11 . 1 ,  11 . 2 ,  11 . 3 . Connections  11 . 1  and  11 . 2 , respectively, are represented in sectional views A-A and C-C of  FIG. 1  in the following figures. By analogy, the explanations pertaining to connections  11 . 1 ,  11 . 2  also apply to connection  11 . 3 . In the simplest case, the individual connections are achieved by a connecting element, which simultaneously acts to set the distance between two pendulum masses  2 A,  2 B forming a pair. Preferably, spacer bolt  12 . 1  is used for connection  11 . 1  and spacer bolt  12 . 2  is used for connection  11 . 2 . Each spacer bolt  12 . 1 ,  12 . 2  passes through pendulum mass support  3 . Spacer bolts  12 . 1 ,  12 . 2  create a firm connection between two pendulum masses  2 A,  2 B, thus, forming pendulum mass unit  2 . For this purpose, individual spacer bolts  12 . 1 ,  12 . 2  are designed as step pins having two respective axial stop surfaces  13 . 1 ,  14 . 1  and  13 . 2 ,  14 . 2 , respectively, for two facing front faces  15 A,  15 B of two pendulum masses  2 A,  2 B. Spacer bolt portion  16 . 1 ,  16 . 2  that passes through pendulum mass support  3  is designed to be larger than width a of pendulum mass support  3 , thus, creating spaced distance a on both sides between pendulum masses  2 A,  2 B and pendulum mass support  3 . As explained above, the dimensions of this distance a are determined by the width of portion  16 . 1 ,  16 . 2 , respectively, the position of axial stop surfaces  13 . 1 ,  14 . 1  and axial stop surfaces  13 . 2 ,  14 . 2  for spacer bolt  12 . 2 , and width b of pendulum mass support  3 . The attachment of individual pendulum mass  2 A,  2 B on spacer bolt  12 . 1 ,  12 . 2  is achieved in a force-fitting and/or form-fitting way, for instance using axial securing elements for locking individual pendulum mass  2 A,  2 B relative to axial stop surfaces  13 . 1 ,  14 . 1  and  13 . 2 ,  14 . 2 , respectively. In one embodiment, the attachment may be implemented in a non-releasable form-fitting way using rivet connections  17 . 1 ,  18 . 1  and  17 . 2 ,  18 . 2 , respectively. For this purpose, the rivets are integrally formed on spacer bolt  12 . 1 ,  12 . 2  and are created during assembly. 
         [0057]    The oscillating support of individual pendulum mass  2 A,  2 B is achieved using at least one pendulum bearing assembly. In the present example, two pendulum bearing assemblies  5 . 1 ,  5 . 2  are provided. They include rolling elements  8  designed as rolling bodies or idler rollers guided on a corresponding track. The construction of a pendulum bearing assembly will be explained with reference to pendulum bearing assembly  5 . 1 , which is illustrated in a sectional view B-B in the following figures. In the illustrated example, a movement of individual pendulum mass  2 A,  2 B relative to pendulum mass support  3  is made possible by rolling elements  8  that are guided in tracks  6 A,  6 B and  7  and are designed as rolling bodies or idler rollers. Tracks  6 A,  6 B are formed as recesses in respective pendulum mass  2 A,  2 B, i.e., track  6 A is a recess in pendulum mass  2 A and track  6 B is a recess in pendulum mass  2 B. Track  7  is formed as a recess in pendulum mass  3 . In the simplest case, the recess is in the shape of through-holes having a geometry that matches the desired contour of tracks  6 A,  6 B, or  7 . For example, on individual pendulum masses  2 A,  2 B, it is conceivable to provide tracks  6 A,  6 B embodied as depressions formed in pendulum masses  2 A,  2 B. The geometry and dimensions of individual tracks  6 A,  6 B,  7  determine the acceptable freedom to move of individual pendulum mass  2 A,  2 B. Guide means  19 ,  20  for axially guiding and securing individual rolling elements  8  on pendulum mass support  3  are provided on individual rolling element  8 . Guide means  19 ,  20  may be embodied as a radial extension. In the illustrated example, guide means  19 ,  20  are integral with rolling element  8  and form shoulders. Guide means  19 ,  20  that face each other in pairs on rolling element  8  are preferably arranged at a suitable axial distance to each other that essentially corresponds to width b of pendulum mass support  3  in an area about track  7 . The distance between these guide means  19 ,  20  and the width of these guide means  19 ,  20  determine respective minimum distance a min  between individual pendulum mass  2 A,  2 B, respectively, and pendulum mass support  3  in the area of pendulum bearing assembly  5 . 1 ,  5 . 2 . Minimum distance a min  cannot be reduced at will. The greater distance a min , the greater the risk that individual pendulum masses  2 A,  2 B may tilt sideways under certain operating conditions; a phenomenon that frequently occurs on both sides at low centrifugal forces, i.e., at a low rotational speed. 
         [0058]      FIGS. 2   a  to  2   c  illustrate the coupling of individual pendulum masses  2 A′,  2 B′ to pendulum mass support  3  of the prior art as shown in the three sectional views A-A, B-B, and C-C of  FIG. 1 . The figures illustrate required minimum distance a min ′ between pendulum mass  2 A′,  2 B′ and pendulum mass support  3 ′. Minimum distance a min ′ is required over the entire extension of pendulum mass  2 A′,  2 B′ relative to pendulum mass support  3  because of the axial width of guide means  19 ′,  20 ′. In the other views A-A and C-C shown in  FIGS. 2   a  and  2   c,  minimum distance a min ′ is likewise present between pendulum mass  2 A′,  2 B′ and pendulum mass support  3 ′. Due to the size of minimum distance a min ′, there is always a risk that pendulum masses  2 A,  2 B may tilt relative to pendulum mass support  3 ′. This may have undesired effects. Thus, the invention proposes to eliminate or at least reduce the risk of tilting. In one embodiment, this is attained using means  21  for reducing the axial distance between pendulum mass support  3  and pendulum masses  2 A,  2 B arranged thereon at least in a locally limited way. Such means may be embodied in different ways. A distinction is made between embodiments in which means  21  are formed integrally with pendulum masses  2 A,  2 B and/or with pendulum mass support  3  and embodiments in which means  21  are separate devices. 
         [0059]    The first alternative includes the use of separate add-on elements. The views in the following figures correspond to sectional views A-A, B-B and C-C of  FIG. 1 . 
         [0060]      FIGS. 3   a  to  3   c  illustrate a first alternative of a second basic embodiment in the aforementioned sectional views A-A, B-B, C-D of  FIG. 1 .  FIG. 3   a  represents a sectional view A-A of  FIG. 1 . In this embodiment, means  21  include a respective add-on element in the form of disc-shaped element  22 ,  23 . Each of these add-on elements is arranged between pendulum mass support  3  and pendulum mass  2 A,  2 B arranged on respective front face  4 . 1  or  4 . 2  of pendulum mass support  3 . The add-on elements in the form of disc-shaped elements  22  and  23  are designed and arranged in a way to be arranged over the entire extension of respective facing front faces  15 A,  15 B of individual pendulum masses  2 A,  2 B in the radial and circumferential directions. In the region of the formation of tracks  6 A,  6 B and  7 , in the region passable by guide means  19 ,  20  in the gap and in the region of the through-holes for the connecting elements of connections  11 . 1 ,  11 . 2 , the add-on elements are recessed. For easy manufacturing, the add-on elements are preferably designed as sheet metal disc components. They cover almost the entire surface of front faces  15 A,  15 B of individual pendulum masses  2 A,  2 B and are shaped to match the outer contour of pendulum masses  2 A,  2 B. 
         [0061]      FIG. 3   a  illustrates the view A-A of  FIG. 1 . This illustration shows that the individual add-on elements rest against the entire surface of front faces  15 A,  15 B of pendulum masses  2 A,  2 B and are arranged between pendulum masses  2 A,  2 B and axial stop surfaces  13 . 1 ,  13 . 2  of spacer bolt  12 . 1 . The figure also shows through-holes  31 ,  32  for the axial end regions of spacer bolt  12 . 1  and resultant reduced distance a V  between pendulum mass  2 A,  2 B and pendulum mass support  3 . The add-on elements in the form of disc-shaped elements  22 ,  23  are assigned to pendulum masses  2 A,  2 B and are fixed thereto. The fixing is achieved by means of spacer bolt  12 . 1 , which is present in any case. Spacer bolt  12 . 1  has axial end regions that are designed to be suitable for forming a rivet head to form rivet connection  17 . 1 ,  18 . 1 . 
         [0062]      FIG. 3   b  is a sectional view B-B through pendulum bearing assembly  5 . 1 . This view illustrates required minimum distance a min  between pendulum mass support  3  and individual pendulum mass  2 A,  2 B. Distance a min  needs to be maintained in the region of guide means  19 ,  20  and in the region the guide means pass upon a rolling movement of rolling element  8 . It can be seen that individual disc-shaped element  22 ,  23  is recessed in these regions to provide minimum distance a min  for this region; that is to say that disc-shaped element  22 ,  23  includes openings or through-holes  33 ,  34 , which are preferably greater than the region to be kept clear or which may exactly match the geometry of the region that is passed upon a movement. The recesses are dimensioned in such a way that they are designed to maintain a distance for receiving guide means  19 ,  20  when rolling elements  8  rest on the respective rolling surfaces on radially inward rolling surface  9  or on radially outward rolling surface  10 . Guide means  16  must be prevented from getting into contact with the add-on elements at all times. 
         [0063]    The sectional view C-C of  FIG. 1  shown in  FIG. 3   c  illustrates the arrangement of the add-on elements in the region of connection  11 . 2 . The basic construction corresponds to the embodiment shown in  FIG. 3   a.  Disc-shaped elements  22 ,  23  have through-holes  35 ,  36  for receiving spacer bolt  12 . 2 . In this case, too, the connection is a rivet connection. The rivet connections are designated by numbers  17 . 1 ,  18 . 2 . This Figure also shows reduced distance a v . 
         [0064]    The add-on elements in the form of disc-shaped elements  22 ,  23  are arranged and designed in such a way that their surfaces are always at same reduced distance a v  in the ideal position relative to pendulum mass support  3 . It is likewise conceivable to provide elevations or depressions in the surface facing pendulum mass support  3 ; and thus, the resultant gap may vary in terms of its width in the radial and/or circumferential direction. 
         [0065]    Compared to the embodiments shown in  FIGS. 3   a  to  3   c,    FIGS. 4   a  to  4   c  illustrate a first alternative of a first basic embodiment in which means  21  do not include add-on elements embodied as elements that cover entire front faces  15 A,  15 B of pendulum masses  2 A,  2 B. Instead, add-on elements in the form of washers  24 ,  25  and  26 ,  27  are arranged in a locally limited way. The washers are riveted on both sides between pendulum mass  2 A,  2 B and spacer bolt  12 . The add-on elements in the form of washers  24  to  27  are arranged only in the region of rotationally fixed connections  11 . 1 ,  11 . 2  and, in analogy,  11 . 3 . Although the add-on elements are arranged only in a partial region of the gap, they permit a reduction of the distance in this region, thus, preventing tilting over entire pendulum mass unit  2  due to the arrangement of connections  11 . 1 ,  11 . 2 ,  11 . 3  between individual pendulum masses  2 A,  2 B. Each one of individual connections  11 . 1 ,  11 . 2 ,  11 . 3  of individual pendulum masses  2 A and  2 B of pendulum mass unit  2  includes the introduction of washers  24 ,  25  of this kind in  FIG. 4   a  and of washers  26 ,  27  in  FIG. 4   c.  The region of pendulum bearing assemblies  5 . 1  (shown in  FIG. 4   b ) and  5 . 2  (not illustrated) is free of such washers. 
         [0066]      FIG. 4   a  is an axial section through connection  11 . 1 . Washer  24  is arranged between axial stop surface  13 . 1  and pendulum mass  2 A. Washer  25  is arranged between pendulum mass  2 B and axial stop surface  14 . 1 . It can be seen that the outer diameter of washers  24 ,  25  needs to be greater than that of through-hole  37 , through which spacer bolt  12 . 1  passes through pendulum mass support  3 . The interior diameter of individual washers  24 ,  25  is preferably adapted to the diameter of the axial end regions of spacer bolt  12 . 1 . 
         [0067]      FIG. 4   b  illustrates the sectional view B-B of  FIG. 1  for this embodiment. The figure shows that in this region, no washers or space-filling elements are provided. 
         [0068]    In a way analogous to  FIG. 4   a,    FIG. 4   c  illustrates the axial section C-C of  FIG. 1  for connection  11 . 2 . Here, too, washers  26  and  27  are provided on both sides of pendulum mass support  3  between axial stop surfaces  13 . 2 ,  14 . 2  and pendulum masses  2 A,  2 B. The attachment to pendulum masses  2 A,  2 B is done analogously with the embodiment shown in  FIG. 4   a.    
         [0069]    In the illustrated example, for individual connections  11 . 1  to  11 . 3 , the add-on elements in the form of washers  24  to  27  are arranged in a way to hit axial stop surfaces  13 . 1 ,  13 . 2  and  14 . 1 ,  14 . 2  in spacer bolt  12 . 1 ,  12 . 2 . To achieve a reduction of the axial distance, spacer bolt  12 . 1 ,  12 . 2  with its region  16 . 1 ,  16 . 2  is designed to be of smaller width than in a prior art embodiment as shown in  FIGS. 2   a  to  2   c.    
         [0070]      FIGS. 5   a  to  5   c  illustrate a further development of the first alternative of the first basic embodiment shown in  FIGS. 4   a  to  4   c.  In this embodiment, axial stop surfaces  13 . 1 ,  13 . 2  and  14 . 1 ,  14 . 2  are embodied as stop surfaces for individual pendulum masses  2 A,  2 B, with washers  24 ,  25  and  26 ,  27  being loosely arranged in the space between pendulum mass support  3  and individual pendulum masses  2 A,  2 B. What is to be ensured, however, is that washers  24  and  25  do not hit the pendulum mass support  3 . For this reason, in the regions of axial stop surfaces  13 . 1 ,  13 . 2  and  14 . 1 ,  14 . 2 , spacer bolts  12 . 1  and  12 . 2 , respectively, are designed in a way that they likewise fix washers  24 ,  25  and (for the embodiment of  FIG. 5   c )  26 ,  27  in position. In the simplest case, the washers are designed to be supported in the region of the chamfer or pressed onto spacer bolt  12 . 1 ,  12 . 2 . 
         [0071]    Further alternatives of the first alternative of the first basic embodiment are shown in  FIGS. 6 and 7 . They include the provision of separate add-on elements  28 ,  29  or  30  that are integrated or supported in the individual components of pendulum mass  2 A,  2 B and/or pendulum mass support  3 . These add-on elements may be of different designs such as balls, half-shells, cylinder pins, or the like, which form at least one axial protrusion extending into the gap. The crucial aspect is that they create an axial extension into the gap between pendulum mass  2 A,  2 B and pendulum mass support  3 . 
         [0072]    Based on a sectional view through connection  11 . 1  of section A-A of  FIG. 1 ,  FIG. 6  illustrates an integration of such add-on elements  28  and  29  in the form of spherical elements supported or fixed in corresponding receiving elements  38 ,  39  on individual pendulum masses  2 A,  2 B. With respect to the width of individual pendulum masses  2 A,  2 B, add-on elements  28 ,  29  are arranged on or integrated in pendulum masses  2 A,  2 B in a way to form a respective axially protruding projection on respective facing front faces  15 A,  15 B of individual pendulum masses  2 A,  2 B. The add-on elements may be arranged on pendulum masses  2 A,  2 B in any desired way. The crucial aspect is that the resultant locally-limited distance reduction is achieved outside the motion range of guide means  19 ,  20  in the gap. 
         [0073]    In contrast,  FIG. 7  illustrates an alternative arrangement of such add-on elements. In this sectional view of section B-B of  FIG. 1 , an add-on element  30  that is likewise designed as a spherical element is arranged in receiving element  40  on pendulum mass support  3 . Add-on element  30  is arranged and dimensioned to form an axial protrusion into the gap. 
         [0074]    The embodiments shown in  FIGS. 6 and 7  are merely examples. Means  21  may include any desired add-on elements that are suitable for forming axially protruding regions on pendulum masses  2 A,  2 B and/or on pendulum mass support  3 . They may be movably supported on pendulum masses  2 A,  2 B or on pendulum mass support  3 , or they may be fixed thereto or integral therewith. If they are fixed, the connection may be a force-fitting, form-fitting, or material-locking connection. The type of arrangement depends on the required regions of reduced distance in the gap that are to be created. 
         [0075]    The number, geometry and dimensions of the regions of locally-limited distance reduction to be created by the add-on elements are selected to match the requirements of the individual case. 
         [0076]      FIGS. 8 to 10  illustrate embodiments of a second alternative of a first basic embodiment in which means  21  are integral with at least one of the components of pendulum mass  2 A,  2 B and/or pendulum mass support  3 . 
         [0077]      FIGS. 8   a  and  8   c  illustrate the locally limited arrangement of coined elements  41 ,  42  provided on pendulum masses  2 A,  2 B in the region of connection  11 . 1  and of coined elements  43 ,  44  provided on pendulum masses  2 A,  2 B in the region of their connection  11 . 2  effected by spacer bolt  12 . 2 . Coined elements  41 ,  42  and  43 ,  44  are arranged in the region of the through-holes for spacer bolt  12 . 1  and  12 . 2 , respectively, through pendulum masses  2 A,  2 B. In the radial direction, they are dimensioned so that their outer circumference is arranged on a greater diameter with respect to spacer bolt  12 . 1 ,  12 . 2  than the diameter of the through-hole on the pendulum mass support  3 . In the illustrated example, coined elements  41 ,  42  are embodied to rest against axial stop surfaces  13 . 1 ,  14 . 1 , and coined elements  43 ,  44  are embodied to rest against axial stop surfaces  13 . 2 ,  14 . 2 . Here, the regions of reduced distance a v  are created between coined elements  41  and  43  on pendulum mass  2 A, and respectively, coined elements  42  and  44  on pendulum mass  2 B and pendulum mass support  3 . Coined elements  41  to  44  preferably define flat surfaces directed towards the pendulum mass support. The region of pendulum masses  2 A,  2 B arranged about coined elements  41 ,  42  and  43 ,  44 , respectively, is free from such coined elements and acts to provide the required distance in the range of motion of guide means  19 ,  20  of rolling element  8  between pendulum mass  2 A,  2 B and pendulum mass support  3 . 
         [0078]    Coined elements  41 ,  42 ,  43 , and  44  need not necessarily be arranged as shown in  FIGS. 8   a  to  8   c.  They may be arranged in a different location on pendulum mass  2 A,  2 B. The only thing to ensure is that the range of motion of guide means  19 ,  20  of rolling element  8  remains clear. 
         [0079]      FIG. 8   b  illustrates pendulum bearing assembly  5 . 1 , which is free from such coined elements. 
         [0080]    In contrast to the embodiment shown in  FIGS. 8   a  to  8   c,    FIGS. 9   a  to  9   c  illustrate a further embodiment in which coined elements forming means  21  are not arranged on pendulum masses  2 A,  2 B, but on pendulum mass support  3 . Coined elements  45  and  46  are arranged on pendulum mass support  3  outside the region of track  7  and the regions passable by guide means  19 ,  20  in the gap. Coined elements  45 ,  46  thus form a depression in the receiving region of rolling element  8  and of the tracks. This depression includes the required minimum distance for the reception of guide means  19 ,  20 . 
         [0081]    Coined elements  45 ,  46  on pendulum mass support  3  are preferably arranged in the region about the tracks of individual pendulum bearing assemblies  5 . 1 ,  5 . 2 . The remaining areas are preferably clear. This can be seen in the sectional views A-A and C-C of  FIGS. 9   a  and  9   c.    
         [0082]    In another embodiment of locally limited surfaces for locally reducing the gap distance is shown in  FIG. 10  in a sectional view A-A of  FIG. 1 . In this embodiment, the local protrusions that extend into the gap in the axial direction are formed as semi-piercings  47  and  48 , each of which is provided on both pendulum masses  2 A,  2 B. Semi-piercings  47 ,  48  are preferably formed on the individual pendulum masses. A (non-illustrated) arrangement on pendulum mass support  3  is conceivable. 
         [0083]    The arrangement of the semi-piercings may be at random. Again the crucial aspects are that the motion range of guide means  19 ,  20  in the gap must not be compromised and that furthermore the protrusion is arranged opposite a counter-surface on the other element, i.e., in the illustrated example, pendulum mass support  3 . Consequently, the semi-piercings will always be arranged outside through-holes on pendulum mass support  3 . 
         [0084]    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 SYMBOLS 
       [0000]    
       
           1 ′,  1  centrifugal pendulum mechanism 
           2 ′,  2  pendulum mass unit 
           2 A′,  2 A pendulum mass of a pendulum mass unit 
           2 B′,  2 B pendulum mass of a pendulum mass unit 
           3 ′,  3  pendulum mass support 
           4 . 1 ′,  4 . 1  front face 
           4 . 2 ′,  4 . 2  front face 
           5 . 1 ′,  5 . 1  pendulum bearing assembly 
           5 . 2 ′,  5 . 2  pendulum bearing assembly 
           6 A,  6 B track 
           6 A′,  6 B′ track 
           7 ′,  7  track 
           8 ′,  8  rolling element 
           9 ′,  9  radially inward rolling surface 
           10 ′,  10  radially outward rolling surface 
           11 . 1 ′,  11 . 1  rotationally fixed connection 
           11 . 2 ′,  11 . 2  rotationally fixed connection 
           11 . 3 ′,  11 . 3  rotationally fixed connection 
           12 . 1 ′,  12 . 1  spacer bolt 
           12 . 2 ′,  12 . 2  spacer bolt 
           13 . 1 ′,  13 . 1  axial stop surface 
           14 . 1 ′,  14 . 1  axial stop surface 
           13 . 2 ′,  13 . 2  axial stop surface 
           14 . 2 ′,  14 . 2  axial stop surface 
           15 A′,  15 A front face of a pendulum mass 
           15 B′,  15 B front face of a pendulum mass 
           16 . 1 ′,  16 . 1  portion 
           16 . 2 ′,  16 . 2  portion 
           17 . 1 ′,  17 . 1  rivet connection 
           17 . 2 ′,  17 . 2  rivet connection 
           18 . 1 ′,  18 . 1  rivet connection 
           18 . 2 ′,  18 . 2  rivet connection 
           19 ′,  19  guide means 
           20 ′,  20  guide means 
           21  means for reducing the gap distance at least in a locally limited way 
           22 ,  23  disc-shaped elements 
           24 ,  25  washers 
           26 ,  27  washers 
           28  add-on element 
           29  add-on element 
           30  add-on element 
           31  through-hole 
           32  through-hole 
           33  through-hole 
           34  through-hole 
           35  through-hole 
           36  through-hole 
           37  through-hole 
           38  receiving element 
           39  receiving element 
           40  receiving element 
           41  coined element 
           42  coined element 
           43  coined element 
           44  coined element 
           45  coined element 
           46  coined element 
           47  semi-piercing 
           48  semi-piercing 
         R axis of rotation 
         b width of pendulum mass support 
         a min ′ distance 
         a v  reduced distance