Abstract:
An assembly for transferring torque including a first component having first wall portions, a second component having second wall portions, wherein the first wall portions extend radially from the first component toward the second component, the second wall portions extend radially from the second component toward the first component, the first wall portions are axially aligned with the second wall portions, and a clearance is formed between the first and second wall portions, and a ring rivet having a connecting portion inserted into the clearance and deformed for creating at least one head for axially locking the first component and the second component together, and wherein deforming the connecting portion fills the clearance for rotationally locking the first component and second component together for enabling a transfer of torque between the first component and the second component.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit under 35 U.S.C. §119(e) of U.S. Provisional Patent Application No. 61/443,034 filed Feb. 15, 2011, which application is incorporated herein by reference. 
    
    
     FIELD OF THE INVENTION 
     The invention broadly relates to torque transferring assemblies, more specifically to axially compact torque transferring assemblies, and even more particularly to a deformable ring rivet for enabling torque to be transferred between two axially aligned components. 
     BACKGROUND OF THE INVENTION 
     Rivet connections are commonly used in torque converters, for example, for securing a damper flange to a damper hub. For example, see U.S. Pat. No. 7,658,679 (Avins et al.), which patent is hereby incorporated by reference in its entirety. Rivets may also be used between any other two components that transfer or transmit torque. Riveted connections, such as between the damper flange and the hub, require a large number of rivets that must be individually inserted during assembly and then deformed in a riveting die. A large number of rivets is required in order to reduce the shear stress levels in each rivet to an acceptable level for transferring torque between the flange and the hub, thereby increasing assembly time. In addition, the flange and the hub are axially stacked, which requires additional axial space. Another option is to secure the damper flange to the hub with a splined connection, however this can be expensive and time consuming to manufacture due to the strict tolerances, for example, that must be met to ensure a good connection between the parts. Vibrations will result in the system if the splined connection is not manufactured precisely. Therefore, there is needed, for example, an assembly that connects two torque transferring components without a splined connection or a plurality of individual rivets, and that saves axial space by connecting the components in an axially aligned orientation. 
     BRIEF SUMMARY OF THE INVENTION 
     The present invention broadly comprises an assembly for transferring torque including a first component having a first plurality of first wall portions, a second component having a second plurality of second wall portions, wherein the first wall portions extend radially from the first component toward the second component, the second wall portions extend radially from the second component toward the first component, the first wall portions are axially aligned with the second wall portions, and a radial clearance is formed between the first and second wall portions, and a ring rivet having a connecting portion inserted into the radial clearance between the first and second wall portions and deformed for creating at least one head on at least one axial side of the assembly for axially locking the first component and the second component together, and wherein deforming the connecting portion of the ring rivet fills the radial clearance for creating a positive fit between the connecting portion and each of the first and second components for rotationally locking the first component and second component together for enabling a transfer of torque between the first component and the second component. 
     In one embodiment, the first component comprises a radially extending plate and the second component comprises an annular projection extending radially from the second component, wherein the annular projection is axially aligned with the first component and includes the second wall portions. In one embodiment, the first component includes a first set of first notches, each of the first notches forming two of the first wall portions, wherein the second component includes a second set of second notches in the annular projection, each of the second notches forming two of the second wall portions, and wherein each of the first notches is paired with one of the second notches for together forming a plurality of enlarged openings as part of the radial clearance for engagement with the connecting portion of the ring rivet. In a further embodiment, the connecting portion of the ring rivet comprises a plurality of tabs extending axially from a ring body. In yet another embodiment, the tabs each have a first shape and the enlarged openings each have a second shape, and the first and second shapes are each selected from the group consisting of a rectangular shape, an arced shape, and a herringbone shape. In another embodiment, the first shape is the arced shape and the second shape is the rectangular shape. In one embodiment, the first shape has a first width and a first thickness, the second shape a second width and a second thickness, and the first width is less than the second width and the first thickness is less than the second thickness. 
     In one embodiment, the ring rivet is formed as an undulating ring and the connecting portion of the ring rivet comprises an alternating plurality of radially arranged crests and troughs. In a further embodiment, the first component has a first set of first teeth, wherein each first tooth in the first set forms two of the first wall portions, and the second component has a second set of second teeth, wherein each second tooth in the second set forms two of the second wall portions. In another embodiment, the connecting portion is deformed on both opposite axial sides of the assembly. 
     The current invention also broadly comprises an assembly for transferring torque in a torque converter including a damper flange having a first plurality of first wall portions, a hub having a second plurality of second wall portions, wherein the first wall portions extend radially from the damper flange toward the hub, the second wall portions extend radially from the hub toward the damper flange, the first wall portions are axially aligned with the second wall portions, and a radial clearance is formed between the first and second wall portions, and a ring rivet having a connecting portion inserted into the radial clearance between the first and second wall portions and deformed for creating at least one head on at least one axial side of the assembly for axially locking the damper flange and the hub together, and wherein deforming the connecting portion of the ring rivet fills the radial clearance for creating a positive fit between the connecting portion and each of the damper flange and the hub for rotationally locking the damper flange and hub together for enabling a transfer of torque between the damper flange and the hub. 
     In one embodiment, the damper flange comprises a radially extending plate and the hub comprises a radially extending, annular projection wherein the annular projection is axially aligned with the radially extending plate and includes the second wall portions. In one embodiment, the damper flange includes a first set of first notches, each of the first notches forming two of the first wall portions, wherein the hub includes a second set of second notches in the annular projection, each of the second notches forming two of the second wall portions, and wherein each of the first notches is paired with one of the second notches for together forming a plurality of enlarged openings as part of the radial clearance for engagement with the connecting portion of the ring rivet. In another embodiment, the connecting portion of the ring rivet comprises a plurality of tabs extending axially from a ring body. In a further embodiment, the tabs each have a first shape and the enlarged openings each have a second shape, and the first and second shapes are each selected from the group consisting of a rectangular shape, an arced shape, and a herringbone shape. In one embodiment, the first shape is the arced shape and the second shape is the rectangular shape. In another embodiment, the first shape has a first width and a first thickness, the second shape a second width and a second thickness, and the first width is less than the second width and the first thickness is less than the second thickness. 
     In one embodiment, the ring rivet is formed as an undulating ring and the connecting portion of the ring rivet comprises an alternating plurality of radially arranged crests and troughs. In another embodiment, the damper flange has a first set of first teeth, wherein each first tooth in the first set forms two of the first wall portions, and the hub has a second set of second teeth, wherein each second tooth in the second set forms two of the second wall portions. In one embodiment, the connecting portion is deformed on both opposite axial sides of the assembly. 
     It is a general object to create a connection between two torque transmitting components in an axially compact manner. It is another general object to reduce the number of components needed for assembly of a torque transferring system. It is another general object to create a positive fit between two torque transferring components. These and other objects and advantages of the present invention will be readily appreciable from the following description of preferred embodiments of the invention and from the accompanying drawings and claims. 
    
    
     
       BRIEF DESCRIPTION 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 an exploded perspective view of a torque transferring assembly according to a first embodiment of the current invention; 
         FIG. 2  is a cross-sectional view of two torque transferring components of the assembly of  FIG. 1 ; 
         FIG. 3  is a perspective view of the assembly of  FIG. 1 ; 
         FIG. 4  is a view of a first axial side of the assembly of  FIG. 1  before upsetting; 
         FIG. 5  is a view of a second axial side of the assembly of  FIG. 1  before upsetting; 
         FIG. 6  is a cross-sectional view of the assembly before upsetting taken generally along line A-A in  FIG. 4 ; 
         FIG. 7  is a perspective view of the assembly of  FIG. 1  after upsetting; 
         FIG. 8  is a cross-sectional view of the assembly taken generally long line A-A in  FIG. 4 , but after upsetting; 
         FIG. 9  is a cross-sectional view of a ring rivet of the assembly of  FIG. 1  being upset in a die set; 
         FIG. 10A  illustrates examples of shapes for tabs and/or openings of the assembly of  FIG. 1 ; 
         FIG. 10B  illustrates an example of a tab in an opening for the  FIG. 1  assembly; 
         FIG. 11  is a cross-sectional view of a torque transferring assembly according to a second embodiment of the current invention; 
         FIG. 12  is a cross-sectional view of the assembly generally taken along line B-B in  FIG. 11 , before upsetting; and, 
         FIG. 13  is a cross-sectional view of the assembly generally taken along line B-B in  FIG. 11 , after upsetting. 
     
    
    
     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. It should be appreciated that the term “upset” refers to the riveting process in which the rivet is smashed, pressed, or otherwise deformed in order to secure two or more components together. 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. 
     Referring now to the figures,  FIG. 1  shows an exploded view of assembly  10 . Assembly  10  includes flange  12  connected to hub  14 , specifically radial projection  15  of hub  14 , via ring rivet  16 . Ring rivet  16  includes ring body  18  with a plurality of tabs  20  extending axially from the inner diameter of the ring body. The ring body is formed as an essentially continuous ring that is matingly engagable against an axial surface of the flange or hub. It should be appreciated that the tabs could alternatively extend from the outer diameter, or some other portion of the ring body. Each tab has a width, designated width w 1 , and a thickness, designated thickness t 1 . 
     Flange  12  includes notches  22 A about its inner diameter, while projection  15  of hub  14  includes notches  22 B about its outer diameter. As can be seen in  FIG. 2 , flange  12  and hub  14  are complementarily formed such that projection  15  of hub  14  fits radially within the inner diameter of flange  12 . Interface  24 , shown in  FIG. 2 , is formed between the outer diameter of the hub and inner diameter of the flange. The interface may include some small amount of radial clearance to ensure the two components will fit together easily. For example, unlike a splined connection, looser tolerances can be used in current invention assemblies. When axially and rotationally aligned, notches  22 A and  22 B together form openings  22 . Openings  22  are operatively sized having width w 2  and thickness t 2  for receiving tabs  20  therethrough. The openings are likewise formed with some clearance and/or as an enlarged portion of the clearance between the flange and the hub, for example, to enable less strict tolerances to be used and/or to increase the ease of assembly. As shown in  FIG. 4 , ring body  18  of ring rivet  16  is matingly engaged against the flange so that, as shown in  FIG. 3 , tabs  20  extend axially through openings  22 . The tabs will later be upset or deformed in order to fill the clearance. 
     Notches  22 A define wall portions  25 A and  25 B, and notches  22 B define wall portions  27 A and  27 B, for transferring torque between flange  12  and hub  14  via tabs  20  on ring rivet  16 . Following the direction indicated by arrow R, wall portions  25 A and  27 B are located on one side of notches  22 A and  22 B, respectively, from wall portions  25 B and  27 A. The wall portions are essentially radially extending surfaces that radially overlap the tabs of the ring rivet, such that rotation of the flange and/or hub results in the wall portions of the flange and/or hub pressing on the tabs. By radially overlap, it is meant that there is at least a portion of both components that is located within the same range of radial distances. Wall portions  25 A and  25 B are further in a radial direction orthogonal to axis of rotation A than wall portions  27 B and  27 A, respectively, as seen in  FIG. 2 . 
     Tabs  20  of ring rivet  16  are shown in  FIGS. 7-9  after they have been upset in order to form head  26 . Forming of head  26  results in plastic deformation of the tabs so that the tabs expand in the radial and circumferential directions, with respect to axis of rotation A, in order to axially lock the flange and hub together between head  26  and ring body  18 . The ring body also helps support the ring rivet during the upsetting process. Furthermore, the tabs expand in order to fill any clearance between the flange and the hub to create a positive fit or positive lock between the components. By positive fit or lock it is generally meant that the tabs have expanded to such a degree that there is interference between the tabs and the walls of the openings and/or that the tabs are exerting pressure on the walls of the openings in the radial and/or circumferential directions. 
     The radial overlap between the wall portions and the tabs enables the two components to transfer torque between each other. With respect to  FIGS. 1 and 2 , which have the best views of the wall portions of flange  12  and hub  14 , assume assembly  10  is entirely assembled and tabs  20  have been inserted into openings  22  and upset as described above. Then, once assembled, rotation of flange  12  about axis A in the direction indicated by arrow R will result in torque being transferred from the flange to the ring rivet via wall portions  25 A, which wall portions radially overlap tabs  20  in openings  22 . This will result in tabs  20  transferring the torque to wall portions  27 A of projection  15  of hub  14 , which wall portions radially overlap the tabs. On the other hand, rotation of the flange in the direction opposite to the direction of arrow R would result in wall portions  25 B transferring torque to the tabs, which would then transfer the torque to wall portions  27 B of the projection of the hub. Each notch thus forms two torque transferring wall portions, although only one wall portion of each notch is used for each direction of rotation of the assembly. In this way, torque can be transferred between the hub and flange while the hub and flange are axially aligned for saving axial space. By axially aligned, it meant that the components are located at substantially the same axial distance along axis A. 
     Since all of the tabs are formed on the ring rivet, only a single component, as opposed to a plurality of individual rivets, needs to be installed during assembly. In prior art systems, for example, the damper flange is either axially stacked (not axially aligned) with an annular projection of the hub, with a portion of the hub and flange radially overlapping for securing a plurality of rivets through (as shown in Avins et al., incorporated supra). The prior art therefore requires more axial space than current invention assemblies. Saving axial space, for example, enables other components of the torque converter to be increased in size, in order to increase the capacity or performance of the torque converter without increasing overall size, or to save on material costs and/or create a smaller overall sized torque converter. The flange could alternatively be secured to the hub with a splined connection, however, splined connections are expensive and time consuming to manufacture due to strict tolerances that must be met for proper meshing of the splined connection. 
     The upsetting process could use, for example, dies on opposite sides of the ring rivet in order to upset the tabs. For example, dies  28  and  30  are shown in  FIG. 9  for upsetting the tabs of the ring rivet. In the example of  FIG. 9 , die  30  includes two features to help the tabs deform properly. Specifically, die  30  includes dimple  32 , which is formed, for example, as an annular raised portion or plurality of raised portions that align on rivet body  18  of the ring rivet opposite tabs  20 . Die  30  may also include radial wall  34 , that engages with the outer circumference of ring body  18 . Dimple  32  and radial wall  34  assist in the flow of material of the ring rivet to fill the clearance around the tabs in the openings. For example, the dimple helps direct material into openings  22  to assist in the expansion of the tabs in openings  22  by concentrating force directly into the tabs, while radial wall  34  prevents the ring body from expanding, which causes material to instead flow into the openings to expand the tabs and lock the components together. 
     Several possible shapes for openings  22  and/or tabs  20  are shown in  FIG. 10A , although it should be understood that other shapes could be used. For example, shape  36  is substantially rectangular having width w 3  and thickness t 3 . Shape  38  resembles shape  36 , having width w 4  and thickness t 4 , but having a slight curvature to one set of parallel sides (e.g., the curvature substantially corresponding to the inner/outer diameter of the flange/hub or defined by a radius concentric with the inner/outer diameters). Shape  38  is generally referred to as the arced shape. Shape  40  likewise generally resembles shape  36 , with width w 5  and thickness t 5 , but with one set of parallel sides having resembling nested, shallow v-shapes. Shape  40  is generally referred to as the herringbone shape. For example,  FIG. 10B  shows an example with tab  42 , having shape  38 , engaged in opening  44 , having shape  36 . As mentioned above, it should be more easily appreciated in view of  FIG. 10B  that before upsetting, clearance  46  exists about the tab in the opening, but this clearance is filled when the tab is upset. That is, the tab is expanded so that it presses against the walls of the opening. 
     Filling the clearance, for example, removes any play, or relative motion, between the flange and hub, thereby reducing rattling and increasing performance. For this reason, the clearance should be kept small in order to ensure the tab can expand sufficiently to fill the clearance. For example, filling the clearance may result in frictional, contact, and/or interference forces between the circumferential surfaces of the tabs and openings, which help to transfer torque in addition to wall portions  25 A and  25 B. It should also be appreciated, for example that increasing tab thickness, such as thickness t 1  (and thicknesses t 3 , t 4 , or t 5  in some embodiments) increases the amount of torque that can be transmitted, while increasing tab width, such as width w 1  (and widths w 3 , w 4 , or w 5  in some embodiments) reduces the shear stress from torque transmission. 
     In one embodiment, flange  12  is a flange for a damper of a torque converter, while hub  14  is a turbine hub for a torque converter. However, in view of the above description, it should be understood that flange  12  and hub  14  generally represent any two components in torque converters or other torque transferring devices, which need to be rotationally locked together for transferring torque between them and/or which need to be connected in an axially aligned, space-saving manner. As one example of a torque converter damper flange and hub, it has been found that suitable results can be achieved for a typical torque converter using twenty tabs on a ring rivet, with a radial clearance gap of 0.3 mm between the two components, the radial clearance gap located at a radial distance of approximately 38 mm-40 mm (e.g., interface  24  located approximately 39 mm from axis A with 0.3 mm gap between the inner diameter of the flange and the outer diameter of the hub), with the tab width being 6 mm, the tab thickness being 2.75 mm, and the first and second components having an axial thickness of approximately 5 mm. It should be appreciated that this is merely one example and should not be considered limiting to the scope of the current invention, but rather is illustrative of one embodiment that has been found to give suitable results. 
     Another embodiment according to the current invention is shown in  FIGS. 11-13 . In this embodiment, outer component  48  is to be connected to inner component  50  via ring rivet  52 . Outer component  48  includes teeth  54  protruding radially inward from the outer component, which alternatively correspond with teeth  56 , which protrude radially outward from inner component  50 . Ring rivet  52  is formed having a wavy or undulating shape, with crests  58  arranged to accommodate teeth  54  and troughs  60  arranged to accommodate teeth  56 . Thus, the crests are formed as radially outwardly extending portions on the wave-shaped ring rivet, while the troughs are radially inwardly extending portions on the wave-shaped ring rivet. The components are initially assembled with clearance  62  is formed between them. 
     Outer component  48 , inner component  50 , and ring rivet  52  are arranged having a clearance  62  between them, as shown in  FIG. 12 , with the ring rivet extending axially past both the outer and inner components. Thus, teeth  54  and  56  form a mating geometry, similar to a gear meshing or splined connection, except with a relatively large clearance between them for receiving ring rivet  52 . Despite being relatively large in comparison to typical splined connections, clearance  62  may total only approximately 0.3 mm in radial width. Similar to wall portions  25 A,  25 B,  27 A and  27 B, teeth  54  have wall portions  55 A and  55 B and teeth  56  have wall portions  57 A and  57 B. While upsetting the ring rivet, such as with a die set, deformed heads  64  are formed on axially opposite sides of the ring rivet for preventing relative axial movement between the components. In an example embodiment, only portions of ring rivet  52  adjacent to wall portions  55  and  57  are upset to form heads  64 . That is, after upsetting, ring rivet  52  includes a non-upset portion between wall portions  55  and  57 , and an upset portion adjacent to portions  55  and  57 . 
     Upsetting the ring rivet results in the ring expanding to fill the clearance in order to prevent any play between the components for reducing rattling and improving performance. That is, in accordance with the above description of the tabs of the embodiment of  FIGS. 1-9 , the portion of the ring rivet  52  located between the inner and outer components acts as a connecting portion for connecting the outer and inner component rotationally with a positive fit so that torque can be transferred or transmitted between them. For example, after the rivet ring is upset, rotation of outer component  48  in the counter-clockwise direction with respect to the orientation of  FIG. 11  would cause torque to be transferred from outer component  48  to ring rivet  52  via wall portions  55 A of teeth  54 , which wall portions radially overlap and are engaged against crests  58 , with the ring rivet in turn transferring the torque to inner component  50  via wall portions  57 A of teeth  56 , which wall portions radially overlap and are engaged against troughs  60 . Rotation of outer component  48  in the clockwise direction would result in wall portions  55 B of teeth  56  transferring torque to ring rivet  52 , and with the ring rivet in turn transferring the torque to inner component  50  via wall portions  57 B of teeth  56 . Thus, like assembly  10 , the embodiment of  FIGS. 11-13  similarly transfers torque via a ring rivet between two axially aligned components. 
     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.