Abstract:
A bearing assembly including a bearing having an outer bearing ring and an inner bearing ring. The outer bearing ring is axially received in a bearing-receiving recess that includes a substantially cylindrical inner wall. An element that is radially flexible is located between at least one of the outer bearing ring and the inner wall of the recess, and the inner bearing ring and a rotatable member that is rotatably carried in the bearing assembly. The flexible element includes at least one annular element that is undulated in the radial direction, or is provided with projections. Flexible elements can also be disposed against a side surface of the bearing ring for damping axial vibrations.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS  
         [0001]    The present application is a continuation of International Application No. PCT/DE01/03736.  
         BACKGROUND OF THE INVENTION  
         [0002]    1. Field of the Invention  
           [0003]    The invention relates to a bearing assembly for a rotatable shaft, particularly of a motor vehicle transmission. Furthermore, the invention pertains to a spring, particularly for use in a bearing assembly and a transmission for use in an above-named bearing assembly.  
           [0004]    2. Description of the Related Art  
           [0005]    The comfort requirements for motor vehicles are generally very high, particularly with respect to acoustics. Especially in case of the high-end motor vehicles, the driver and the passengers don&#39;t want to hear background noises arising from the operation of the motor vehicle&#39;s components during operation. However, internal combustion engines as well as other components such as transmission generate noises, which might generally be perceived as nuisance. In the case of progressively adjustable transmissions, noise might arise when a plate link chain is used because, due to the fact that such a plate link chain is made up of plate links and pins, it generates a recurring knocking sound as the pins touch the cone disks of the transmission.  
           [0006]    DE 199 58 073 provides an acoustic vibration damping layer. As it turns out, these layers settle or undergo changes in their elastic properties during operation of the bearing and the transmission, so that they do not display the same acoustic properties and/or results over the course of their life.  
           [0007]    The object of the present invention is damping the noise generated during the operation, ideally at the point of origin or at least in the surrounding area, so that, to the extent possible, this noise does not make its way into the passenger compartment, whereby generating a bearing assembly which does not display the prior state-of-the-art disadvantages or does so only to a limited extent and which, nonetheless, allows for very good acoustic decoupling over the course of its life.  
         SUMMARY OF THE INVENTION  
         [0008]    According to the invention this is being achieved in the case of a bearing assembly particularly for the rotatable&#39;shafts of the power train transmission of a motor vehicle with a bearing featuring an outer bearing ring and an inner bearing ring, the outer bearing ring being axially fixed in a recess to the lateral walls of said recess and the recess featuring an essentially cylindrical inner wall with an element which is flexible in the radial direction, located between the outer bearing ring and the inner wall of the recess, in that the flexible element consists of at least one annular element that is undulated in the radial direction, or is provided with projections, and flexible elements are disposed in an axial direction for damping vibrations.  
           [0009]    Furthermore, according to the invention, this is being achieved in the case of a bearing assembly particularly for the rotatable shafts of the power train transmissions of a motor vehicle with a bearing featuring an outer bearing ring and an inner bearing ring. The outer bearing ring being axially fixed in a recess to the lateral walls of the said recess and the recess featuring an essentially cylindrical inner wall, with an element which is flexible in the radial direction located between the outer bearing ring and the inner wall of the recess, in that the flexible element consists of at least one annular element that is undulated in the radial direction, or is provided with projections.  
           [0010]    According to another inventive idea this can be achieved in the case of a bearing assembly particularly for the rotatable shafts of the power train transmission of a motor vehicle with a bearing featuring an outer bearing ring and an inner bearing ring. The outer bearing ring being axially fixed in a recess to the lateral walls of said recess and the recess featuring an essentially cylindrical inner wall, with an element which is flexible in the radial direction located between the inner bearing ring and a recess of a shaft, in that the flexible element consists of at least one annular element that is undulated in the radial direction, or is provided with projections, and flexible elements are disposed in an axial direction for damping vibrations.  
           [0011]    To that purpose, it is useful if the annular element is designed as a band, which projections protruding in the radial direction have been worked in. These projections can be designed as impressions such as radial formations that extend in the axial direction and protrude radially to the outside or inside. The radial formations on the annular element can also face in a direction diagonal to the axis of the annular element. To that end, it is useful if the annular elements are designed as essentially circular rings featuring areas protruding in a radial direction to the inside and/or outside.  
           [0012]    To that purpose, it is also useful if the annular elements are designed as essentially sinus-like undulated rings.  
           [0013]    In the case of this design it is also useful, if the annular elements are designed as closed rings. In the case of another design it is useful if the annular elements are designed as open rings.  
           [0014]    It is preferable if the outer bearing ring and the inner wall of the recess are supported in the radial direction by areas of the rings, which are located on the radial inside and radial outside respectively. It also makes sense for the inner bearing ring and an outer wall of the recess to be supported in the radial direction by areas of the rings, which are located on the radial inside and/or radial outside respectively.  
           [0015]    Furthermore, this can be achieved in the case of a bearing assembly particularly for the rotatable shafts of a transmission in the power train of a motor vehicle with a bearing featuring an outer bearing ring and an inner bearing ring. The outer bearing ring being axially fixed in a recess to the lateral walls of said recess and the recess featuring an essentially cylindrical inner wall, with an element which is flexible in the radial direction located between the inner bearing ring and a recess of a shaft, in that the flexible element consists of at least one annular element that is undulated in the radial direction or provided with projections.  
           [0016]    To that purpose, it is preferable if the flexible element consists of several annular elements undulated in the radial direction or provided with projections, which [elements] are placed side by side or spaced. Accordingly, it can be useful if the annular elements are stacked side by side. Pursuant to another idea it is useful if the annular elements are spaced with the help of spacers.  
           [0017]    To that purpose, it is useful if the annular elements are designed as closed rings. It may also be useful if the annular elements are designed as open rings.  
           [0018]    To that purpose, it is particularly useful if the annular elements are designed as essentially sinusoidally-formed, undulating ring sections. Pursuant to another design it may be useful if the annular elements are formed like essentially circular rings with areas protruding to the inside and/or outside in the radial direction. It is particularly beneficial if, in the peripheral direction, the areas protruding to the inside in the radial direction are staggered against the areas protruding to the outside in the radial direction.  
           [0019]    Pursuant to the invention it is useful if the areas protruding to the inside and/or outside areas in the radial direction are arranged in a staggered manner.  
           [0020]    Pursuant to the invention it is useful if the outer bearing ring and the inner wall of the recess are supported in the radial direction by areas of the rings, which are located on the radial inside and radial outside, respectively. It also makes sense for the inner bearing ring and an outer wall of the recess to be supported in the radial direction by areas of the rings, which are located on the radial inside and radial outside, respectively.  
           [0021]    It makes sense if the annular elements are made out of metal. It may be useful if the annular element is made out of wire.  
           [0022]    In the case of one embodiment it is preferable if the annular element is made out of metal. In the case of one design is may be useful if the annular element is made out of wire.  
           [0023]    In the case of another embodiment it is useful if the annular element is made out of plastic.  
           [0024]    Pursuant to the invention it is useful if in the area of the bearing shell, which touches the radially flexible element, i.e., the inner and/or outer bearing shell, at least on one side of the bearing shell an axially flexible element is located between the lateral surface of the bearing shell and a lateral wall.  
           [0025]    It is also useful if an axially flexible element is located between the lateral surfaces of the bearing shells, i.e., inner and/or outer bearing shell, and the lateral walls respectively.  
           [0026]    It is advantageous if the axially flexible elements are  0 -rings or flexible rings.  
           [0027]    It is also useful if the axially flexible elements are flexible ring wheels.  
           [0028]    It is particularly advantageous if the axially flexible elements are made out of elastic materials such as plastic, rubber, or metal.  
           [0029]    In preferable embodiments, axially layered rings can be arranged differently along the perimeter; rings with identical and/or different peripheral profiles such as inner and/or outer profiles, for embodiment, can be added to one another with a twisting angle, thereby forming the inner bearing shell. Precise contours can be created through the use of separating manufacturing processes such as, followed by, but not limited to, precision blanking, laser cutting, water jet separation and the like, using suitable materials such as spring steel, plastic and/or materials with good acoustic vibration damping characteristics. Furthermore it may be beneficial to arrange different materials in an axial direction using a layer construction method in order to form an inner bearing ring. In doing so, the materials can be chosen, e. g., among statically solid materials, on the one hand, and substances with good acoustic vibration damping characteristics, on the other hand.  
           [0030]    The individual axially layered rings can feature any inner and outer contours, which may be independent of one another and/or turned in the same or opposite directions. That way, non-linearities such as progression at the inner bearing ring itself and/or asymmetries along the axial course of the inner bearing ring can be adjusted, taking into account the main load direction for embodiment. With these measures, the overall characteristic line can be influenced to a large extent. At the same time, the elastic support can be homogenized through axially layered spring elements that are turned in opposite directions. The axial stiffness of the inner bearing ring can be regulated through an appropriate design of the individual annular elements and, if necessary, adjusted to the shearing forces between the bearing ring and the recess surface of the bearing. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0031]    The structure, operation, and advantages of the present invention will become further apparent upon consideration of the following description, taken in conjunction with the accompanying drawings in which:  
         [0032]    [0032]FIG. 1 is a cross-sectional view of part of a belt-drive transmission;  
         [0033]    [0033]FIG. 2 is an enlarged, fragmentary, cross-sectional view of an embodiment of a bearing assembly in accordance with the present invention;  
         [0034]    [0034]FIG. 3 an enlarged, fragmentary, cross-sectional view of a bearing assembly including elastic elements;  
         [0035]    [0035]FIG. 4 is a view similar to that of FIG. 3 showing a different form of elastic elements;  
         [0036]    [0036]FIG. 5 a  is a perspective view of one form of elastic annular element;  
         [0037]    [0037]FIG. 5 b  is a view similar to that of FIG. 5 a  showing another form of elastic element;  
         [0038]    [0038]FIG. 6 is a view similar to that of FIG. 3 showing a further form of elastic element;  
         [0039]    [0039]FIG. 7 is a view similar to FIG. 2 showing another form of elastic element; and  
         [0040]    [0040]FIG. 8 is a perspective view of the elastic element shown in FIG. 7 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0041]    [0041]FIG. 1 shows only part of a belt-driven conical pulley transmission, i.e., the part of the belt-driven conical pulley transmission  1  at the driving or input end that is driven by a motor, such as an internal combustion engine. In the case of a fully implemented belt-driven conical pulley transmission, a complementary driving end part of the progressively adjustable transmission is allocated to this input end part, both sides being interconnected by a drive belt such as a plate link chain  2  for torque transmission. The belt-driven conical pulley transmission  1  features a shaft  3  at the input end, which, in the design displayed here, has a single-piece fixed conical disk  4 .  
         [0042]    This axially fixed conical disk  4  is located along the axial length across from shaft  3  and adjacent to an axially displaceable cone disc  5 .  
         [0043]    In FIG. 1 the plate link chain  2  at the drive end conical disk pair  4 ,  5  is displayed in an outer radial position which is a result of the axially displaceable conical disk  5  being moved to the right in the Figure and this movement of the axially displaceable conical disk  5  leads to a movement of the plate link chain  2  in a radial direction toward the outside, whereby the gear is shifted into high gear.  
         [0044]    The axially displaceable conical disk  5  can also be shifted to the left in the Figure in a known manner. In this position the plate link chain  2  is displayed in an inner radial position (referenced as  2   a ) and the belt-driven conical pulley transmission is shifted into low gear.  
         [0045]    In FIG. 1, the torque generated by a driving motor, which is not closely described, is introduced into the drive end part of the belt-driven conical pulley transmission, which is displayed in FIG. 1, through a gear  6  located on shaft  3 , which is located on shaft  3 through a rolling contact bearing in the form of a ball bearing  7  absorbing axial and radial forces, which is fixed on shaft  3  through a disk  8  and a shaft nut  9 . Between the gear  6  and the axially displaceable conical disk  5 , a torque sensor  10  is located to which a spacer configuration  13  is arranged, which contains an axially fixed spacer  11  and an axially displaceable spacer  12 . Between the two spacers  11 ,  12  there are roll bodies that are, for embodiment, designed as the balls  14  displayed in the Figure.  
         [0046]    A torque introduced through the gear  6  leads to the development of a swing angle between the axially fixed spacer  11  and the axially displaceable spacer  12 , causing the spacer  12  to shift axially. Specifically it is based on this arranged acceleration ramps on which the balls  14  roll up and thus, together, provide for an axial offset of the spacers against one another.  
         [0047]    The torque sensor  10  contains two pressure chambers  15 ,  16 . The first pressure chamber  15  is provided for impact of a hydraulic fluid depending on the torque introduced, and the second pressure chamber  16  is supplied with hydraulic fluid depending on the gear ratio of the transmission.  
         [0048]    A piston/cylinder unit  17  with two pressure chambers  18 ,  19  is provided for generating the force which presses with a normal force against the plate link chain  2  between the axially fixed conical disk  4  and the axially displaceable conical disk  5 . The first pressure chamber  18  serves, in connection with pressure chamber  15  of the torque sensor  10 , which is controlled in relation to the torque, to increase or decrease the force which presses against the plate link chain  2  between the cone disks  4 ,  5 , and the second pressure chamber serves to change the force pressing on the plate link chain  2  in relation to the gear ratio.  
         [0049]    The shaft  3  contains three channels for supplying hydraulic fluid to the pressure chambers. Through said channels, hydraulic fluid is being fed into the pressure chambers by a pump, which is not shown.  
         [0050]    Through a discharge channel  21 , the hydraulic fluid can drain from the shaft  3  and be reintroduced into the cycle.  
         [0051]    The force applied in the pressure chambers  15 ,  16 ,  18 , and  19  causes the axially displaceable conical disk  5  on the shaft to shift in relation to the torque and the gear ratio to the shaft  3 . The shaft  3  features centering surfaces  22  for accommodating the shifting conical disk  5 , which serve as a sliding seat for the shifting conical disk  5 .  
         [0052]    As can easily be seen in FIG. 1, the belt-driven conical pulley transmission  1  features one acoustic vibration damping unit  23  each in the area of the bearings of the conical disk  5  on the shaft  3 . To that end, the acoustic vibration damping unit might feature an annular body and a vibration damping insert or consists solely of a vibration damping insert.  
         [0053]    [0053]FIG. 2 shows a bearing assembly  100  of a shaft  102 , whereby the shaft is seated so it can be revolved by the bearing  103  located near a housing  101  of a transmission. The inner bearing ring  103   a  is located on a lug  102   a  of the shaft. The outer bearing ring  103   b  is located axially between a shoulder  105  of the housing  101  and a safety panel  106  connected to the housing. It is accommodated in such a way that the outer bearing ring has some clearance  110  in the axial direction, so that it can move slightly in the radial direction.  
         [0054]    Between the outer bearing ring  103   b  and a cylindrical receiver surface  121  is a vibration damping device  120 , arranged like a spring clip element. Said vibration damping device is preferably made out of sheet metal with projections protruding in the radial direction pursuant to the FIGS. 5 a  and  5   b . The spring clip element is designed as an open ring and features a gap  130 , see FIG. 5 a  or  5   b . In another embodiment, the rings can be designed as closed rings without the gap.  
         [0055]    The spring ring elements are modulated in their radial span so that there are areas  140  in which the rings protrude further to the outside in the radial direction and areas  141  in which the rings reach further to the inside in the radial direction. The spring ring element might feature a progressive force path as a function of the excursion, as a spring characteristic. In the embodiment shown in FIG. 2, the dimensions of the scope of the potential shift of the bearing rings are proportionally excessively enlarged compared to the diameter of the bearing to better illustrate the invention. It is advantageous if a shift between 0.05 mm and 1 mm, preferably 0.1 mm and 0.3 can occur.  
         [0056]    To limit the extent to which shifting can occur, the lateral walls of the retainer of the outer bearing ring and in the safety panel stops  106  are developed through the edges  150  and  151 .  
         [0057]    The spring rings can be manufactured out of metal, i. e. through precision blanking or bending. Preferably, the metal is a spring steel or spring steel sheet.  
         [0058]    [0058]FIGS. 3 and 4 show sections of bearing assemblies pursuant to the invention where the bearing with its outer bearing ring and/or inner bearing ring is accommodated such that it can shift in both the axial and radial directions. Furthermore, elastic elements  220  and  221  are provided in the axial direction between the bearing ring  205  and the lateral face  210  on the one hand and the lateral face  211  on the other hand, which clamp the bearing ring axially while allowing it to shift marginally.  
         [0059]    The elastic elements  220  and  221  can be o-rings or other annular elements manufactured out of an elastic material such as plastic, rubber, elastomers, or metal. Furthermore the elastic element can be composed of a layered material consisting of different materials.  
         [0060]    [0060]FIG. 4 shows an embodiment of an axially elastic accommodation where the axially elastic elements  230  and  231  are designed as disk-like or annular elements. As it turns out, it is useful when the elastic element consists of two metal layers on the outside with an elastic layer sandwiched in between. It is beneficial if the vibration damping material features good internal damping characteristics. This can, for embodiment, be an elastomer or a fiber reinforced material.  
         [0061]    [0061]FIGS. 5 a  and  5   b  show radial elastic rings  180  and  190 , which are metal bands with radial formations  181  and  192 . The radial formations can be in the form of corrugations or pleats, with the radial formations extending radially inwardly in the case of the element shown in FIG. 5 a , and extending radially outwardly in the case of the element shown in FIG. 5 b.  In the case of a metal element, the radial formations can be formed using a process such as a deep-drawing process.  
         [0062]    Pursuant to another embodiment shown in FIG. 6, the acoustic decoupling of the shaft from the housing is achieved by providing a circular assembly  210  between the outer bearing ring  201  and the housing receiver  200  of the outer bearing ring, which is essentially composed of several layers. In this embodiment the multi-layer element is composed of two metal layers  210   a  and  210   c  with an elastic layer  210   b  sandwiched between them. However, the middle layer  210   b  could also be made out of metal, such as sheet metal.  
         [0063]    In the case of the embodiment displayed here, the multi-layer construction serves, on the one hand, to reflect the sound waves at the outer layers of the respective materials and thus reduce the transmission intensity, i.e. reduce noise. On the other hand, joint damping as well as material damping occurs. The joint damping occurs due to the relative movements of the individual layers against one another and their contact surfaces. If the interposed sheet metal shown in this version is additionally shaped in such a way that the ridges between the slits are bent slightly, vibration damping occurs as well, which is caused by the spring action present.  
         [0064]    [0064]FIG. 7 shows a bearing assembly  300  of a shaft  302  with the shaft rotatable on a bearing  303  located near a housing  301  of a transmission. The inner bearing ring  303   a  is located on a lug  302   a  of the shaft. The outer bearing ring  303   b  is located axially between a shoulder  305  of the housing  301  and a safety panel  306  connected to the housing. It is accommodated in such a way that the outer bearing ring has some play  310  in the axial direction, so that it can move slightly in the radial direction.  
         [0065]    Between the outer bearing ring  303   b  and a cylindrical retainer surface  321 , there is a vibration damping device  320  like a radial shaft spring. This vibration damping device, preferably according to FIG. 8, is in the form of an assemblage of individual, side-by-side ring-shaped springs identified by reference numerals  321  through  326 . The individual spring rings  321  through  326  are designed as open rings and include a gap  330 . In another embodiment, the rings can be designed as closed rings without the gap.  
         [0066]    The individual rings are modulated in their radial span so that there are areas  340  in which the rings protrude further to the outside in the radial direction and areas  341  in which the rings reach further to the inside in the radial direction. It is advantageous if these areas, spread out over the length of the rings, are staggered against one another from ring to ring, forming a contact surface on the radial inside and radial outside, to allow contact with the bearing ring and/or the contact surface, so that a uniform contact pattern is created.  
         [0067]    The radial shaft spring might feature a progressive force curve as a function of the excursion, as a spring characteristic, which can also be created through an axially stacked arrangement of spring rings. This can be achieved using several identical spring rings or different types of spring rings, which allow for a different characteristic curve of the spring characteristic. The different types of spring rings can be generated, for embodiment, by modulating the thickness of the clips or the projections or shafts in the radial direction. Furthermore the radial shape of the rings can be formed in different ways to produce varying characteristics. Furthermore, the thickness of the individual rings can vary, so that individual rings are blocked when the bearing ring shifts, limiting further shifts. The rings can also be shaped in such a way that some rings are blocked sooner than others.  
         [0068]    In the embodiment shown in the FIGS. 7 and 8, the dimensions of the scope of the potential shift of the bearing rings is enlarged out of proportion, compared to the diameter of the bearing, to better illustrate the invention. It is advantageous if a shift of 0.05 mm and 1 mm, preferably in the range of 0.1 mm and 0.3, can occur.  
         [0069]    To limit the extent to which shifting can occur, stops are formed in the lateral walls of the receptor of the outer bearing ring and in the safety panel  306  by the edges  350 ,  351 . Furthermore, some rings can only be formed as stiff rings without any elastic qualities.  
         [0070]    The spring rings can be manufactured out of metal, i. e. through precision blanking or bending. Preferably, the metal is a spring steel or spring steel sheet.  
         [0071]    It is furthermore advantageous if the spring rings feature a slight axial stiffness, which is aided by the fact that the rings are stacked.  
         [0072]    The claims included in the application are illustrative and are without prejudice to acquiring wider patent protection. The applicant reserves the right to claim additional combinations of features disclosed in the specification and/or drawings.  
         [0073]    The references contained in the dependent claims point to further developments of the object of the main claim by means of the features of the particular claim; they are not to be construed as a waiver of independent, objective protection for the combinations of features of the related dependent claims.  
         [0074]    Although the subject matter of the dependent claims can constitute separate and independent inventions in the light of the state of the art on the priority date, the applicants reserve the right to make them the subject of independent claims or separate statements. They can, moreover, also embody independent inventions that can be produced from the independent developments of the subject matter of the included dependent claims.  
         [0075]    The exemplary embodiments are not to be considered to be limitations of the invention. On the contrary, many changes and variations are possible within the scope of the invention in the existing disclosure, in particular such variants, elements, and combinations and/or materials which, for example, are inventive by combining or modifying single features that are in combination and are described individually in relation to the general specification and embodiments as well as the claims and shown in the drawings, as well as elements or method steps that can be derived by a person skilled in the art in the light of the disclosed solutions of the problem, and which by means of combined features lead to a new object or new method steps or sequences of method steps, as well as manufacturing, testing and operational procedures.