Abstract:
A cage for a one-way clutch that is made of individual interlocking links. The cage links forms a continuous chain which is arranged on a shaft and housed within an associated outer ring. The cage links have connecting members and receiving grooves. The connecting members of one cage link are snapped into the receiving grooves of another cage link to form the continuous chain for different diameters. Sprags and/or load bearing rollers, along with spring elements, are arranged within each cage link.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the priority of U.S. 61/559,905 filed Nov. 15, 2011, which is incorporated by reference herein. 
     
    
     FIELD OF INVENTION 
       [0002]    The present invention relates generally to clutches and more particularly to a cage comprised of individual interconnected cage links for one-way clutches. 
       BACKGROUND OF THE INVENTION 
       [0003]    Typically, one-way clutches, which freewheel in one rotational direction and transmit torque in the other direction, utilize cages to hold sprags or rollers. One-way clutches are used for a wide variety of applications including industrial power transmission equipment, automobile transmissions, torque converters, material handling equipment, and manufacturing equipment. Regularly, one-way clutches are arranged on a shaft of the application and include an outer ring. Depending on the application, the cage can be applied directly onto the shaft or the cage can also include an inner ring. The cages used in known one-way clutches, which can, for example, be made of molded polymer or formed metal, include one-piece cages, two-piece cages, and cages made of links assembled together. Springs can be anchored to the cage or, alternatively, a separate ring can be incorporated to supply a spring force to the sprags or the rollers that are arranged within the cage. 
         [0004]    The tooling costs associated with the production of a one-piece cage are usually a large initial investment. Cages used in one-way clutches are typically produced from tooling dedicated to the production of cages that can accommodate only a single shaft diameter and a single outer ring diameter. Thus, the tooling cost associated with the production of cages for one-way clutches arranged on different shaft and outer ring diameters can require a large initial investment as separate dedicated tooling is required to produce cages for different shaft and outer ring diameters. 
         [0005]    Also, the spring(s) used in existing one-way cages add to the expense of the cage because the springs are expensive, require separate assembly, are difficult to install in the cage, and require separate inspection. 
         [0006]    Moreover, external of the cage, centering washers are regularly used with one-way clutch cages to supply a requisite radial support between a shaft and an outer ring. However, centering washers add to the expense and the complexity of a clutch assembly as the centering washer has narrow tolerances for accurately centering the shaft in an outer race. A plain bearing material, such as brass or bronze, is often used for the washer. Stamped steel washers can also be used. Typically, stamped steel washers are plated with a cupric plain bearing alloy to reduce sliding friction. However, the alloys and tight tolerances required make the centering washers expensive. Furthermore, the centering washer(s) is placed alongside the one-way clutch cage, which adds to the overall axial space requirement of the one-way clutch. 
         [0007]    See, for example, U.S. Pat. No. 5,651,438, which discloses interlocking cage segments for roller clutches. The cage segments are positioned between an outer cam race and an inner pathway race and have an engaging member, which engages a receiving member on an adjacent cage segment. The cage segments also include a roller positioned within the cage and a resilient means, such as a spring, positioned within the cage to bias the roller. 
         [0008]    Also, see, for example, U.S. Pat. No. 4,555,002, which discloses sectioned cage construction for a one-way clutch. Here, the cage has adjoinable sections with abuttable flanges thereon. Rollers are arranged within each cage segment and a spring is partially arranged within each cage section and snap-fitted around the flanges to join the cage sections together. 
         [0009]    Moreover, see, for example, U.S. Pat. No. 3,702,649, which discloses a one-way clutch that has sprags arranged between an inner race and an outer race. Studs project axially from the sprags and springs are mounted on the studs. 
       SUMMARY OF THE INVENTION 
       [0010]    The present invention is directed to a cage for a one-way clutch that is made of individual interlocking links. The chain of cage links forms a continuous loop to fit around a given shaft and is housed within an associated outer ring. The cage can accommodate a broad range of diameters of devices by varying the number of links used in a cage assembly. For example, increasingly large shaft diameters can be accommodated by increasing the number of links in the cage. The tooling cost is minimized as the cage is adaptable to accommodate various diameters. Also, a spring element can be molded integral to each cage link without an added purchasing or assembly expense. Alternatively, a metal spring element could be used. 
         [0011]    The cage allows for the incorporation of sprags and/or load bearing rollers to act on the raceways, between which the cage is arranged. To center the cage containing only sprags a centering washer can be used, however, the rollers can be used in place of centering washers, which reduces friction, simplifies clutch design, and reduces purchasing and inspection cost. The rollers provide radial support between a shaft or an inner ring and an outer ring in a compact and efficient manner and the rollers reduce the overall assembly width of the cage. The ratio of cage links containing rollers to sprags can be adjusted depending on the application. 
         [0012]    Broadly, the present invention relates to a cage for a one-way clutch, which comprises a plurality of cage links that have connecting members and receiving grooves. The connecting members of one of the cage links are snapped into the receiving grooves of another of the cage links so as to form an endless chain of cage links. The connecting members have an axis of rotation and are rotatable about the axis of rotation in both a positive and a negative direction. The cage links are constructed so that the links can be combined to form endless chains of various lengths and diameters. The cage also comprises a spring element arranged within each cage link and a rotatable element, which can be a sprat and/or a roller, arranged within each cage link. The cage links can be molded of a polymer resin or other suitable material. 
         [0013]    The cage link can have a substantially U-shaped opening formed form a first sidewall, a second sidewall, spaced from the first sidewall, and a base that connects the first sidewall and the second sidewall together. A first end of the first sidewall extends from a first end of the base in a first direction and a first end of the second sidewall extends from a second end of the base in the first direction. 
         [0014]    The connecting members can be extensions which have substantially circular ends that extend in a second direction from the first end of the first sidewall and the first end of the second sidewall. The receiving grooves can be substantially C-shaped and can be formed in the second end of the first sidewall and the second end of the second sidewall. 
         [0015]    The cage links can also have a first flange formed integral with one of the connecting members that extend from the first end of the base in the second direction and the cage links can have a second flange formed integral with another of the connecting members that extend from the second end of the base in the second direction. 
         [0016]    The spring element can be molded integral to each cage link. More specifically, the spring element can be molded integral to the base of each cage link. Also, the spring element can be made of steel. 
         [0017]    In an embodiment, only sprags can be utilized and arranged within each of the cage links. Alternatively, in another embodiment, both sprags and rollers can be incorporated into the cage. Here, each cage link has only a single rotatable element with the roller arranged in one of the cage links and the sprag arranged in another of the cage links adjacent to the one of the cage links. 
         [0018]    Additionally, the present invention relates to a method for assembling a cage of a one-way clutch, which has a plurality of cage links and rotatable elements. The method comprises the steps of arranging a rotatable element in each cage link, and snapping the cage links together to form an endless chain. The rotatable element can be a sprag and/or a roller. Further, the rotatable element arranged in one of the cage links can be a roller and the rotatable element arranged in another of the cage links, which is adjacent to the one of the cage links, can be a sprag. 
         [0019]    The cage can further comprise spring elements, which are molded integral to each of the cage links. Alternatively, the cage can further comprise spring elements, which are arranged within each of the cage links. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0020]    The present invention will be further understood and appreciated by reading the following description in conjunction with the accompanying drawings, in which: 
           [0021]      FIGS. 1   a,    1   b,    1   c  illustrate an end view, an enlarged detail view (Detail A), and a cross-sectional view along line I-I in  FIG. 1   b  of a known one-way clutch cage design; 
           [0022]      FIG. 1   d  illustrates a front view of a known centering washer; 
           [0023]      FIGS. 2   a ,  2   b ,  2   c  illustrate a cage link of the present invention for use with sprags; 
           [0024]      FIGS. 3   a ,  3   b ,  3   c ,  3   d  illustrate a front view, a perspective view, a cross-sectional view along line III-III in  FIG. 3   d , and an end view of an assembly of the cage links containing sprags; 
           [0025]      FIGS. 4   a ,  4   b  illustrate front views and perspective views of assemblies of the cage links shown in  FIGS. 2   a ,  2   b ,  2   c  for use with one-way clutches of different diameters; 
           [0026]      FIGS. 5   a ,  5   b,    5   c  illustrate a cage link of the present invention for use with rollers; 
           [0027]      FIG. 6   a ,  6   b ,  6   c  illustrate a front view, a cross-sectional view along line V-V of  FIG. 6   c,  and an end view of an assembly of cage links for sprags interspersed between cage links for rollers; and 
           [0028]      FIG. 7  illustrates a cross-sectional view of the sprag and roller assembly from  FIG. 6  as installed on an outer ring and a shaft. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0029]      FIGS. 1   a  and  1   b  illustrate a known cage  10  and a known centering washer  12  for a one-way clutch.  FIG. 1   a  is an end view of the cage  10 . The cage  10  has pockets  14  in which sprags  16  and springs  18  can be inserted.  FIG. 1   b  is an enlarged view of detail A from  FIG. 1   a.    FIG. 1   c  illustrates a sectional view along line  14  of  FIG. 1   b  showing the sprags  16  and the springs  18  arranged within the cage  10 .  FIG. 1   d  illustrates a front view of the centering washer  12 . 
         [0030]      FIG. 2   a  is a top view of a cage link  20  of a first embodiment of the present invention, which is intended for use with a sprag  22 .  FIG. 2   b  is a cross-sectional view along the line II-II in  FIG. 2   a  of the cage link  20  with the sprag  22  arranged therein. In  FIG. 2   b , the cage link  20  has a spring element  24 , which is molded integral to the cage link  20 . The spring element  24  extends in a curved manner from the cage link  20  to provide a sloped surface for the sprag  22  to rotate against. However, any known spring shape can be used. The spring element  24  imparts a force on the sprag  22  to bias the sprag  22 . Alternatively, the spring element does not have to be molded integral to the cage link  20  and the spring element can be a metal spring. 
         [0031]      FIG. 2   c  is a perspective view of the cage link  20  with the sprag  22  arranged therein. The cage link  20  has a substantially U-shaped opening formed form a first sidewall  26 , which has a first end  28  and a second end  30 , a second sidewall  32 , which has a first end  34  and a second end  36 , spaced from the first sidewall  26 , and a base  38 , which has a first end  40  and a second end  42  that connects the first sidewall  26  and the second sidewall  32  together. The second end  30  of the first sidewall  26  extends from the first end  40  of the base  38  in a first direction X 1  and the second end  36  of the second sidewall  32  extends from the second end  42  of the base  38  in the first direction X 1 . The cage link  20  has connecting members  44 , which are extensions  46  with substantially circular ends  48  that extend in a second direction X 2  from the first end  28  of the first sidewall  26  and the first end  34  of the second sidewall  32 . As can be seen in  FIG. 2   c , the first sidewall  26  has a substantially C-shaped groove  50  formed in the second end  30  of the first sidewall  26  and the second sidewall  32  also has a substantially C-shaped groove  52  formed in the second end  36  of the second sidewall  32 . The C-shaped grooves  50 ,  52  are formed so that the substantially circular ends  48  of an adjoining cage link  20  can be snapped into the C-shaped grooves  50 ,  52  of the cage link  20 . The C-shaped grooves  50 ,  52  and the substantially circular ends  48  of the cage links  20  are configured to permit the cage links  20  to be interconnected to form continuous chains of different diameters. Moreover, the cage links  20  have a first flange  54  formed integral with one of the extensions  46 , which first flange  54  extends from the first end  40  of the base  38  in the second direction X 2  and a second flange  56  formed integral with another of the extensions  46 , which second flange  56  extends from the second end  42  of the base  38  in the second direction X 2 . 
         [0032]      FIG. 3   a  shows a continuous chain of cage links  20  containing sprags  22  snapped together and ready for mounting.  FIG. 3   b  is a perspective view of the continuous chain of cage links  20  containing sprags  22  snapped together.  FIG. 3   c  is a cross-sectional view of the continuous chain of cage links  20  containing sprags  22  snapped together.  FIG. 3   d  is an end of the continuous chain of cage links  20  containing sprags  22  snapped together. 
         [0033]      FIG. 4   a  shows assemblies of the cage links  20  containing sprags  22  for use with clutches (now shown) of different diameters.  FIG. 4   b  shows perspective views of assemblies of the cage links  20  containing sprags  22  of  FIG. 4   a  for use with clutches (now shown) of different diameters. 
         [0034]      FIG. 5   a  is a top view of a cage link  58  of a second embodiment of the present invention, which is intended for us with a roller  60 .  FIG. 5   b  is a cross-sectional view along line IV-IV in  FIG. 5   a  of the cage link  58  with the roller  60  arranged within the cage link  58 . In  FIGS. 5   a  and  5   b , the cage link  58  has a spring element  62  molded integral to the cage link  58 . Alternatively, the spring element does not have to be molded integral to the cage link  58  and the spring element can be a metal spring.  FIG. 5   c  is a perspective view of the cage link  58  with the roller  60  arranged within the cage link  58 . The cage links  58  for rollers  60  are intended to be combined with cage links  20  for sprags  22 . As such, the cage links  58  for rollers  60  and the cage links  20  for sprags  22  can be structurally identical with the exception being the integration of the spring element  24  or  62 . As shown in  FIG. 5   c , the spring element  62  is formed integral with the cage link  58  and has a semi-circular shape to at least partially surround the roller  60 . However, any suitable spring shape can be used. 
         [0035]      FIG. 6   a  shows a plurality of interconnected cage links  20  for sprags  22  and cage links  58  for rollers  60  (shown in  FIG. 6   b ) that are connected together, forming an endless chain in a free-state. The cage links  58  containing rollers  60  provide radial shaft support. This enables the assembly to not require an external bearing or a centering washer.  FIG. 6   b  is a cross-sectional side view of the continuous chain of cage links  20 ,  58  containing sprags  22  and rollers  60  snapped together taken along line V-V in  FIG. 6   c .  FIG. 6   c  is an end view of  FIG. 6   a .  FIG. 6   c  shows cage links  20 ,  58  containing sprags  22  and rollers  60 . The cage links  58  containing rollers  60  are interspersed between the cage links  20  containing sprags  22 . 
         [0036]      FIG. 7  shows the assembly of the cage links  20  containing sprags  22  and the cage links  58  containing rollers  60  from  FIGS. 6   a - 6   c  with the sprags  22  in position as installed on an outer ring  64  and a shaft  66 . The sprags  22  in  FIG. 7  are rotated to a ready position, compressing the spring elements  24 . 
         [0037]    The present invention has been described with reference to a preferred embodiment. It should be understood that the scope of the present invention is defined by the claims and is not intended to be limited to the specific embodiment disclosed herein. 
       REFERENCE CHARACTERS 
       [0038]      10  Cage 
         [0039]      12  Centering Washer 
         [0040]      14  Pocket 
         [0041]      16  Sprag 
         [0042]      18  Spring 
         [0043]      20  Cage Link 
         [0044]      22  Sprag 
         [0045]      24  Spring Element 
         [0046]      26  First Sidewall 
         [0047]      28  First End 
         [0048]      30  Second End 
         [0049]      32  Second Sidewall 
         [0050]      34  First End 
         [0051]      36  Second End 
         [0052]      38  Base 
         [0053]      40  First End 
         [0054]      42  Second End 
         [0055]      44  Connecting Member 
         [0056]      46  Extension 
         [0057]      48  Circular End 
         [0058]      50  C-Shaped Groove 
         [0059]      52  C-Shaped Groove 
         [0060]      54  First Flange 
         [0061]      56  Second Flange 
         [0062]      58  Cage Link 
         [0063]      60  Roller 
         [0064]      62  Spring Element 
         [0065]      64  Outer Ring 
         [0066]      66  Shaft 
         [0067]    X 1  First Direction 
         [0068]    X 2  Second Direction