Patent Publication Number: US-2022235827-A1

Title: Power transfer component with clutch having components with geometry for increased strength and/or reduced mass

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of U.S. Provisional Application No. 63/141,680 filed Jan. 26, 2021, the disclosure of which is incorporated by reference as if fully set forth herein. 
    
    
     FIELD 
     The present disclosure relates to a power transfer component with a clutch having components with a geometry that provides the component with increased strength and/or reduced mass. 
     BACKGROUND 
     This section provides background information related to the present disclosure which is not necessarily prior art. 
     Friction clutches are employed in many power transfer components, such as components of a vehicle driveline, to selectively transmit rotary power. A friction clutch typically includes two sets of clutch plates that are interleaved with one another. An axially-directed force is applied to the clutch plates to frictionally engage them with one another so as to permit torque transmission. The magnitude of the torque that can be transmitted through a friction clutch is related to the total area over which the clutch plates contact one another. In situations where it is possible for a relatively large amount of torque to be transmitted through a friction clutch, the size of the friction clutch can become quite large, either in overall diameter (to increase the diameter of the clutch plates to thereby increase the surface area over which the clutch plates contact one another), overall length (to increase the quantity of the clutch plates to thereby increase the surface area over which the clutch plates contact one another), or both. The increased size of the friction clutch can significantly increase the mass of the clutch. 
     SUMMARY 
     This section provides a general summary of the disclosure, and is not a comprehensive disclosure of its full scope or all of its features. 
     In one form, the present disclosure provides a friction clutch with a clutch plate having a hub member, a rim portion and a plurality of rib members. The hub member has a plurality of female hub teeth. The rim portion is disposed concentrically about the hub member and has a rim member and a friction material that is coupled to the rim member. Each of the rib members extend radially between the hub member and the rim member to couple the hub member and the rim member to one another. Each one of the rib members is intersected by at least three of the other rib members. Each of the other rib members intersecting the one of the rib members at a distinct location such that the distinct locations are spaced apart from one another along the one of the rib members. 
     In another form, the present disclosure provides a friction clutch with a clutch plate having a hub member, a rim portion and a plurality of rib members. The hub member has a plurality of female hub teeth. The rim portion is disposed concentrically about the hub member and has a rim member and a friction material that is coupled to the rim member. Each of the rib members extends radially between the hub member and the rim member to couple the hub member and the rim member to one another. The rib members intersect one another between the female hub teeth and the rim member to form a plurality of mass reduction apertures. A region of the clutch plate that is disposed radially between the hub member and the rim member has a first area. The rib members collectively have a second area. The mass reduction apertures collectively have a third area. A sum of the second and third areas is equal to the first area. The third area is greater than the second area. 
     In still another form, the present disclosure provides a friction clutch that includes a hub, which is rotatable about a rotary axis, a clutch housing, and a clutch pack. The clutch housing has a radially-extending segment, a circumferentially-extending segment, and an intermediate segment. The radially-extending segment has an annular shape and is oriented perpendicular to the rotary axis. The circumferentially-extending segment is disposed about the rotary axis concentric with the hub. The circumferentially-extending segment defines a plurality of internal teeth. The intermediate segment connects the radially-extending segment to the circumferentially-extending segment. The clutch housing has a first axial end, which is formed in part by an exterior surface of the radially-extending wall, and a second axial end that is opposite the first axial end and which is formed by the circumferentially-extending segment. The clutch pack is received in the clutch housing and has a plurality of first clutch plates, which are axially-slidably but non-rotatably coupled to the hub, and a plurality of second clutch plates that are interleaved with the first clutch plates. The second clutch plates have a plurality of external teeth that are engaged to the internal teeth on the circumferentially-extending segment to thereby axially-slidably but non-rotatably couple the second clutch plates to the clutch housing. The intermediate segment includes a radially-extending portion, a first frusto-conical portion, a second frusto-conical portion, and a transition portion. The radially-extending portion is concentric about, parallel to, and spaced axially apart from the radially-extending wall. The first frusto-conical portion is coupled to a radially inner side of the radially-extending portion and converges toward the rotary axis with increasing distance along the rotary axis from the radially-extending portion. The first frusto-conical portion has a cone angle with a first magnitude. The second frusto-conical portion is coupled to a radially inner side of the first frusto-conical portion and converges toward the rotary axis with increasing distance along the rotary axis from the first frusto-conical portion. The second frusto-conical portion has a cone angle with a second magnitude that is smaller than the first magnitude. The transition portion connects a radially outer side of the radially-extending segment to a radially inner side of the second frusto-conical portion. The transition portion has a profile that is defined by a radius that directly connects the radially outer side of the radially-extending segment to the radially inner side of the second frusto-conical portion. The radius is centered at a location that is disposed between the first axial end of the clutch housing and the radially inner side of the first frusto-conical portion. 
     Further areas of applicability will become apparent from the description provided herein. The description and specific examples in this summary are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure. 
    
    
     
       DRAWINGS 
       The drawings described herein are for illustrative purposes only of selected embodiments and not all possible implementations, and are not intended to limit the scope of the present disclosure. 
         FIG. 1  is a longitudinal section view of an exemplary driveline component having a clutch constructed in accordance with the teachings of the present disclosure; 
         FIG. 2  is an enlarged portion of  FIG. 1  illustrating a friction clutch in more detail; 
         FIG. 3  is an exploded perspective view of the friction clutch; 
         FIG. 4  is a longitudinal section view of a portion of a clutch housing of the friction clutch; 
         FIG. 5  is a front view of a first clutch plate of the friction clutch; and 
         FIGS. 6 through 9  are front views of alternately configured first clutch plates. 
     
    
    
     Corresponding reference numerals indicate corresponding parts throughout the several views of the drawings. 
     DETAILED DESCRIPTION 
     With reference to  FIG. 1 , an exemplary driveline component constructed in accordance with the teachings of the present disclosure is generally indicated by reference numeral  10 . The driveline component  10  is illustrated to be a transfer case of the type that is selectively operable in a 2-wheel drive mode and a 4-wheel drive mode. It will be appreciated, however, that the teachings of the present disclosure have application to various other types of driveline components, including power take-off units, axle assemblies and electro-hydraulic clutches (e.g., a Haldex® coupling manufactured by BorgWarner Inc. of Auburn Hills, Mich.). 
     The driveline component  10  can include a housing  12 , an input shaft  14 , a two-speed transmission  16 , a first output shaft  18 , a second output shaft  20 , a drive element  22 , a driven element  24 , an endless power transmitting component  26 , a friction clutch  28 , and a clutch actuator  30 . The housing  12  can comprise a pair of housing halves (not specifically shown) that can be fastened together to define an internal cavity  32  into which the input shaft  14 , the first and second output shafts  18  and  20 , the friction clutch  28 , the drive and driven elements  22  and  24 , the endless power transmitting component  26 , and the clutch actuator  30  can be received. 
     The input shaft  14  can be supported for rotation about a first axis  40  relative to the housing  12  by a first bearing  42 . In the example provided, the input shaft  14  has female splined input end  44  that is configured to receive and matingly engage a male splined end (not shown) of power and drive train (not shown) that provides a source of rotary power. 
     The two-speed transmission  16  is a single-stage planetary transmission in the example provided and includes a sun gear  50 , a ring gear  52 , a planet carrier  54  and a plurality of planet gears  56 . The sun gear  50  is coupled for rotation with the input shaft  14 . In the example provided, the sun gear  50  and the input shaft  14  are integrally and unitarily formed such that the sun gear  50  is fixedly coupled to the input shaft  14 . The ring gear  52  is non-rotatably coupled to the housing  12 . The planet carrier  54  is rotatably about the first axis  40  and includes a carrier body  60  and a plurality of carrier pins  62 . The carrier pins  62  are fixedly coupled to the carrier body  60  and are spaced apart about the first axis  40 . Each of the planet gears  56  is rotatably received on an associated one of the carrier pins  62  and is meshingly engaged with the sun gear  50  and the ring gear  52 . A range sleeve  66  is disposed concentrically about the first axis  40  and has set of internal teeth  68  and a set of external teeth  70 . The range sleeve  66  can be moved between a high-range position, in which the set of external teeth  70  are engaged to a set of internal teeth  74  formed on the sun gear  50 , a low-range position, in which the set of external teeth  70  are engaged to a set of internal teeth  76  formed on the carrier body  60 , and a neutral position that is intermediate the high-range position and the low-range position in which the set of external teeth  70  are disengaged from the sets of internal teeth  74  and  76  formed on the sun gear  50  and the carrier body  60 , respectively. 
     The first output shaft  18  includes a first end, which is received into the input shaft  14 , a second end opposite the first end, and a splined segment  80  that is disposed between the first and second ends. A bearing (not specifically shown) can be disposed radially between the first end of the first output shaft  18  and the input shaft  14  and can support the first output shaft  18  for rotation about the first axis  40  relative to the input shaft  14 . The second end of the first output shaft  18  can be fixedly coupled to a first output flange  84 . The first output flange  84  is configured to be coupled to a propshaft (not shown) in a conventional manner to permit rotary power to be transmitted from the first output shaft  18  to another driveline component, such as a rear axle assembly (not shown). A bearing  86  can support the second end of the first output shaft  18  and the first output flange  84  for rotation about the first axis  40  relative to the housing  12 . The splined segment  80  can be engaged to the set of internal teeth  68  formed on the range sleeve  66  to thereby non-rotatably but axially slidably couple the range sleeve  66  to the first output shaft  18 . 
     The second output shaft  20  can be supported for rotation about a second axis  90  relative to the housing  12  by a pair of bearings  92 . The second axis  90  can be parallel to the first axis  40 . The second output shaft  20  can have a second output flange  94  that can be configured to engage a mating flange (not shown) on a propshaft (not shown) that transmits rotary power from the second output shaft  20  to another driveline component, such as a front axle assembly (not shown). 
     The drive element  22  is disposed concentrically about the first output shaft  18  and the driven element  24  can be coupled to the second output shaft  20  for common or joint rotation. The endless power transmitting component  26  is configured to transmit rotary power between the drive element  22  and the driven element  24 . In the example provided, the drive and driven elements  22  and  24  are sprockets and the endless power transmitting component is a loop of chain. It will be appreciated, however, that the drive and driven elements  22  and  24  could be pulleys and the endless power transmitting component  26  could be a belt. 
     With reference to  FIGS. 2 and 3 , the friction clutch  28  can include a clutch hub  100 , a clutch housing  102 , a plurality of first clutch plates  104 , a plurality of second clutch plates  106  and a pressure plate  108 . The clutch hub  100  can have a hub portion  110  and a first plate mount  112 . The hub portion  110  can be non-rotatably coupled to the first output shaft  18  in any desired manner. In the example shown, the hub portion  110  defines a female splined aperture  116  that is received on a male splined segment  118  on the first output shaft  18 . The clutch hub  100  can be received on the first output shaft  18  between a shoulder  120  on the drive element  22  and an external snap ring  122  that is received in a ring groove  124  formed in the first output shaft  18 . The snap ring  122  can be employed to inhibit or limit movement of the clutch hub  100  along the first axis  40  in a direction away from the shoulder on the drive element  22 . The first plate mount  112  can be fixedly coupled to (e.g., integrally and unitarily formed with) the hub portion  110 . The first plate mount  112  can have a radially outer surface with a plurality of spline teeth  130  formed thereon. If desired, a plurality of clutch plate lubricant passages (not shown) can be formed radially through the clutch hub  100  so as to intersect the radially outer surface of the first plate mount  112 . 
     The clutch housing  102  can be a drum-like structure having a radially-extending segment  140 , a circumferentially-extending segment  142 , and an intermediate segment  144 . The radially-extending segment  140  has an annular shape and is oriented perpendicular to the first axis  40 . The circumferentially-extending segment  142  is disposed about the first axis concentric with the clutch hub  100 . The circumferentially-extending segment  142  defines a second plate mount  150  having a plurality of internal teeth  152  that are disposed on the radially inner surface of the circumferentially-extending segment  142 . The intermediate segment  144  connects the radially-extending segment  140  to the circumferentially-extending segment  142 . The clutch housing  102  having a first axial end  160 , which is formed in part by an exterior surface of the radially-extending segment  140 , and a second axial end  162  that is opposite the first axial end  160  and which is formed by an axial end of the circumferentially-extending segment  142  that is opposite the intermediate segment  144 . 
     With reference to  FIG. 4 , the intermediate segment  144  can include a radially-extending portion  170 , a first frusto-conical portion  172 , a second frusto-conical portion  174 , and a transition portion  176 . The radially-extending portion  170  is concentric about, parallel to, and spaced axially apart from the radially-extending segment  140 . The radially-extending segment  140  can be non-rotatably coupled to the drive element  22 . In the example provided, internal teeth (not shown) are formed into the radially-extending segment  140  and is engaged to external teeth (not shown) that are formed on the drive element  22 . The first frusto-conical portion  172  is coupled to a radially inner side of the radially-extending portion  170  and converges toward the first axis  40  with increasing distance along the first axis  40  from the radially-extending portion  170  in a direction toward the radially-extending segment  140 . The first frusto-conical portion  172  has a (first) cone angle  180  with a first magnitude. The second frusto-conical portion  174  is coupled to a radially inner side of the first frusto-conical portion  172  and converges toward the first axis  40  with increasing distance along the first axis  40  from the first frusto-conical portion  172  in the direction toward the radially-extending segment  140 . The second frusto-conical portion  174  has a (second) cone angle  182  with a second magnitude that is smaller than the first magnitude. The transition portion  176  connects a radially outer side of the radially-extending segment  140  to a radially inner side of the second frusto-conical portion  174 . The transition portion  176  has a profile that is defined by a radius  184  that directly connects the radially outer side of the radially-extending segment  140  to the radially inner side of the second frusto-conical portion  174 . The radius  184  is centered at a location that is disposed along the first axis  40  at a location that is between the first axial end  160  of the clutch housing  102  and the radially inner side of the first frusto-conical portion  172 . 
     Returning to  FIGS. 2 and 3 , the first clutch plates  104  can be axially slidably but non-rotatably coupled to the first plate mount  112 . In the example provided, the first clutch plates  104  conventionally have an aperture  200  that defines a plurality of spline teeth  202  and the first plate mount  112  is received into the aperture such that the spline teeth  130  of the first plate mount  112  meshingly engage the spline teeth of the first clutch plates  104 . 
     With reference to  FIGS. 2, 3 and 5 , each of the first clutch plates  104  has a hub member  230 , a rim portion  232  and a plurality of rib members  234 . The plurality of spline teeth  202  (i.e., female hub teeth) are formed on the hub member  230 . The rim portion  232  is disposed concentrically about the hub member  230  and has a rim member  240  and a friction material  242  that is coupled to the rim member  240 . In the example provided, the friction material  242  is formed in circumferentially-extending segments  242   a  ( FIG. 3 ) that are assembled to one another to form a pair of annular structure that are fixedly coupled to the opposite axial surfaces of the rim member  240 . It will be appreciated, however, that the friction material could be formed in fewer or more discrete components, that the discrete components may or may not abut one another in a circumferential direction, or that the friction material  242  could be formed as a single piece. Each of the rib members  234  extends radially between the hub member  230  and the rim member  240  to couple the hub member  230  and the rim member  240  to one another. 
     With specific reference to  FIG. 5 , each one of the rib members  234  is intersected by at least three of the other rib members  234  such that and each of the other three rib members  234  intersects the one of the rib members  234  at a distinct location  250  and the distinct locations  250  are spaced apart from one another along the one of the rib members  234  (e.g., rib member  234   a  is intersected by rib members  234   b ,  234   c  and  234   d  at locations  250   a ,  250   b  and  250   c , respectively, that are distinct from one another and spaced apart from one another along the rib member  234   a ). The locations  250  where the rib members  234  intersect one another are disposed radially between the female hub teeth  202  and the rim member  240  to form a plurality of mass reduction apertures  254 . A region of the first clutch plate  104  that is disposed radially between the hub member  230  and the rim member  240  has a first area (i.e., a total area), while the rib members  234  collectively have a second area, and the mass reduction apertures  254  collectively have a third area. A sum of the second and third areas is equal to the first area. The third area is greater than the second area. 
       FIGS. 6 through 9  depict alternative configuration of the first clutch plates  104 . In some examples, the distinct locations  250  at which the rib members  234  intersect one another are all radially inward of the rim member  240 . 
     In some examples, each of the rib members  234  is tangent to a circle  270  ( FIGS. 5 &amp; 7 ) that is larger in diameter than the female hub teeth  202  and smaller in diameter than the hub member  230 . Optionally, each of the rib members  234  can be formed as a straight (i.e., linear) segment as is specifically shown in  FIG. 7 . Optionally, as shown in  FIG. 5 , a pair of the rib members  234  can be formed along an arc that is tangent to the circle  270  such that the rib members  234  are joined to one another where they are tangent to the circle  270  and each extends outwardly therefrom toward the rim portion  232 . If desired, one of the rib members  234  formed along the arc can have a first width, while the other one of the rib members  234  formed along the arc can have a second width that is smaller than the first width. Configuration in this manner provides the first clutch plate  104  with a torque capacity of a first magnitude in a first rotational direction, and a torque capacity of a second, smaller magnitude in a second rotational direction, which may be desirable, for example, in a situation where rotary power is transmitted through the first clutch plate  104  in a single rotational direction. In the configuration of  FIGS. 5 and 7 , the width of all of the rib members  234  is consistent so that the torque capacity of the first clutch plate  104  is the same in either rotational direction. The configuration of  FIG. 7A  is identical to that of  FIG. 7  except that the innermost ring or circumferential row of the mass reduction apertures  254  shown in  FIG. 7  are omitted in  FIG. 7A  to render the first clutch plate  104  somewhat more easy to manufacture. Nevertheless, each of the rib members  234  in the example of  FIG. 7A  intersects three other rib members  234 . For example, rib member  234   a  intersects rib members  234   b ,  234   c  and  234   d.    
     In some examples, such as the example of  FIG. 5 , the rib members  234  form a hypotrochoid that is disposed entirely between the female hub teeth  202  and the rim portion  232 . The hypotrochoid can be formed by a point P attached to an inner circle IC that rolls around the inside of a larger, outer circle OC, wherein the inner circle IC has a radius r, wherein the point P that is attached to the inner circle IC is spaced by a distance d from a center of the inner circle IC, and wherein a ratio of the distance d divided by the radius r is greater than or equal to 0.4 and less than or equal to 0.8, preferably the ratio is greater than or equal to 0.5 and less than or equal to 0.7, and more preferably the ratio is equal to 0.6. Alternatively, the hypotrochoid is formed by a point P attached to an inner circle IC that rolls around the inside of a larger, outer circle OC, wherein the inner circle IC has a first radius r, wherein the outer circle OC has a second radius R, and wherein a ratio of the first radius r divided by the second radius R is greater than or equal to ¼ and is less than or equal to ½, and preferably the ratio is equal to 5/14. 
     If desired, one or more sets of the mass reduction apertures  254  could be formed to a size and shape that are relatively easier or less expensive to form. For example,  FIG. 6  depicts the two radially inner sets of mass reduction apertures  254  as being formed with a circular shape (i.e., a first set of mass reduction apertures  254  being formed as circular holes of a first diameter, and a second set of mass reduction apertures  254  disposed concentrically about the first set of mass reduction apertures  254  and being formed as circular holes of a second, larger diameter the centers of which are offset in a circumferential direction from the centers of the circular holes that form the first set of mass reduction apertures  254 ).  FIG. 8  depicts an example in which only the radially inward most set of mass reduction apertures  254  are formed with a circular shape.  FIG. 9  depicts all sets of mass reduction apertures  254  as being formed with a circular shape. 
     Returning to  FIGS. 2 and 3 , the second clutch plates  106  can be interleaved with the first clutch plates  104  and can be axially slidably but non-rotatably coupled to the second plate mount  150 . In the example provided, the second clutch plates  106  conventionally have an annular body with an outer diametrical surface that defines a plurality of external spline teeth  300  and the second clutch plates  106  are received into the second plate mount  150  such that the external spline teeth  300  of the second clutch plates  106  meshingly engage the internal teeth  152  of the second plate mount  150 . 
     The first and second clutch plates  104  and  106  can collectively form a clutch pack and the pressure plate  108  can be disposed on a side of the clutch pack that is opposite the radially-extending segment  140  of the clutch housing  102 . The pressure plate  108  can be axially slidably but non-rotatably coupled to the first plate mount  112 . For example, the pressure plate  108  can have an aperture that defines a plurality of internal spline teeth  310  and which receives the first plate mount  112  such that the spline teeth  130  of the first plate mount  112  meshingly engage the internal spline teeth  310  of the pressure plate  108 . 
     With reference to  FIGS. 1 and 2 , the clutch actuator  30  can be any type of actuator that develop and exert force onto the friction clutch  28  to frictionally engage the first and second clutch plates  104  and  106  to one permit the transmission of rotary power between the clutch hub  100  and the clutch housing  102 . In the example provided, the clutch actuator  30  is a conventional ball-ramp actuator of the type that is well known in the art and as such, a detailed discussion of the construction and operation of the ball-ramp actuator need not be provided herein. Briefly, a rotational drag can be applied to the ball-ramp actuator to cause a first ball-ramp ring to thrust away from a second ball-ramp ring and apply a compressive force to the pressure plate  108 , which engages the first and second clutch plates  104  and  106  to one another to cause rotary power to be transmitted from the first output shaft  18 , through the friction clutch  28  and to the drive element  22 . 
     The foregoing description of the embodiments has been provided for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure. Individual elements or features of a particular embodiment are generally not limited to that particular embodiment, but, where applicable, are interchangeable and can be used in a selected embodiment, even if not specifically shown or described. The same may also be varied in many ways. Such variations are not to be regarded as a departure from the disclosure, and all such modifications are intended to be included within the scope of the disclosure.