Abstract:
A selectable one-way clutch includes a pocket plate; a notch plate; engagement pieces housed in housing recesses of the pocket plate; elastic members biasing the engagement pieces; a selector plate switching states of the engagement pieces; and elastic bodies disposed at least in one of contact portions where contact are made between the engagement pieces and the notch plate and contact portions where contacts are made between the engagement pieces and the pocket plate.

Description:
CROSS-REFERENCE TO RELATED APPLICATION(S) 
       [0001]    The present application claims priority to and incorporates by reference the entire contents of Japanese Patent Application No. 2015-228129 filed in Japan on Nov. 20, 2015. 
       BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present disclosure relates to a selectable one-way clutch. 
         [0004]    2. Description of the Related Art 
         [0005]    As a one-way clutch, for example, Japanese Patent Application Laid-open No. 2008-082478 discloses a selectable one-way clutch including a pocket plate in which a strut (an engagement piece) is housed in a plurality of pockets (housing recesses), a notch plate formed with a plurality of notches (engagement recesses), and a selector plate arranged between the pocket plate and the notch plate. 
         [0006]    In such a selectable one-way clutch, a plurality of window holes are formed in a plate thickness direction of the selector plate. The selectable one-way clutch switches between, by rotating the selector plate, a state in which struts are raised through the window holes and engaged with notches and a state in which struts are confined in pockets in portions other than the window holes of a selector plate so as to release the engagement between the struts and the notches. 
         [0007]    In a hybrid vehicle (HV vehicle) having the selectable one-way clutch described above incorporated therein, for example, when Electric Vehicle (EV) running is performed, as illustrated in  FIG. 6  and  FIG. 7 , the vehicle is in a state in which a notch plate  12  rotates in a direction opposite to an engagement direction of a selectable one-way clutch (SOWC)  101  along with rotation of an output shaft system, that is, the vehicle is in an overrun state. 
         [0008]      FIG. 8  illustrates an example of an alignment chart during EV running. As illustrated in  FIG. 8 , the rotation speed of an engine (ENG) becomes zero during the EV running, a first rotating electrical machine (MG 1 ) outputs negative torque, and a second rotating electrical machine (MG 2 ) outputs positive torque. In  FIG. 8 , as indicated by reference character N, the notch plate  12  rotates in the opposite direction (in a negative direction) to the engagement direction of the selectable one-way clutch  101 . 
         [0009]    In the overrun state, for example, when a selector plate  13  rotates and struts  113  are raised as illustrated in  FIG. 6  and  FIG. 7 , as indicated by A to D in  FIG. 6  and  FIG. 7 , there is a possibility that the struts  113  alternately collide with the notch plate  12  and a pocket plate  11  (the bottom part of the pocket  112 ) along with the rotation of the notch plate  12 , and which results in short lifetime in service of the components such as the struts  113  and the like. 
       SUMMARY OF THE INVENTION 
       [0010]    It is an object of the present disclosure to at least partially solve the problems in the conventional technology. 
         [0011]    A selectable one-way clutch includes: a pocket plate having one surface where a plurality of housing recesses are formed; a notch plate having one surface, which faces the one surface of the pocket place, where a plurality of engagement recesses are formed, and configured to rotate relative to the pocket plate; a plurality of engagement pieces having a plate-lake shape and being housed in the respective housing recesses; a plurality of elastic members disposed between bottom parts of the housing recesses and the respective engagement pieces and configured to bias the engagement pieces toward the respective engagement recesses; and a selector plate disposed between the pocket plate and the notch plate and configured to coaxially rotate with a rotation of the pocket plate to switch between a state where the engagement pieces are raised toward the engagement recesses and a state where the engagement pieces are housed in the housing recesses. Further, the selectable one-way clutch is in an engagement state, where the engagement pieces are engaged with the engagement recesses, in a case where the engagement pieces are raised toward the engagement recesses and the notch plate rotates in an engagement direction with respect to the pocket plate and is in a non-engagement state, where the engagement pieces are not engaged with the engagement recesses, in a case where the engagement pieces are housed in the engagement recesses or the notch plate rotates in a non-engagement direction, which is opposite to the engagement direction, with respect to the pocket plate. Further, the selectable one-way clutch further includes elastic bodies, which are disposed at least in one of first contact portions where contact are made between the engagement pieces and the notch plate and second contact portions where contacts are made between the engagement pieces and the pocket plate, the first contact portions and the second contact portions are contact portions where contacts are made when the engagement pieces are raised toward the engagement recesses and the notch plate rotates in the non-engagement direction with respect to the pocket plate. 
         [0012]    The above and other objects, features, advantages and technical and industrial significance of this disclosure will be better understood by reading the following detailed description of presently preferred embodiments of the disclosure, when considered in connection with the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0013]      FIG. 1  is an exploded perspective view schematically illustrating an overall configuration of a selectable one-way clutch according to an embodiment of the present disclosure; 
           [0014]      FIG. 2  is a cross-sectional view schematically illustrating a configuration of a selectable one-way clutch according to a first embodiment of the present disclosure; 
           [0015]      FIG. 3  is a cross-sectional view schematically illustrating a configuration of a selectable one-way clutch according to a second embodiment of the present disclosure; 
           [0016]      FIG. 4  is a cross-sectional view schematically illustrating a configuration of a selectable one-way clutch according to a third embodiment of the present disclosure; 
           [0017]      FIG. 5  is a cross-sectional view schematically illustrating a configuration of a selectable one-way clutch according to a fourth embodiment of the present disclosure; 
           [0018]      FIG. 6  is a cross-sectional view schematically illustrating a configuration of a selectable one-way clutch according to a conventional technique; 
           [0019]      FIG. 7  is a cross-sectional view schematically illustrating a configuration of the selectable one-way clutch according to the conventional technique; and 
           [0020]      FIG. 8  is an alignment chart during EV running. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0021]    Exemplary embodiments of a selectable one-way clutch (hereinafter may be referred to as “SOWC”) according the present disclosure will be described with reference to the accompanying drawings. The present disclosure is not limited to the following embodiments. Constituent elements in the following embodiments include elements that can be replaced by persons skilled in the art or that are substantially equivalent. 
       First Embodiment 
       [0022]    An SOWC  1  is incorporated in a power transmission device in, for example, a hybrid vehicle, and is switches between an engagement state (a lock state) and a non-engagement state (an unlock state) by rotating a switching member (a selector plate described below) arranged between a fixed side lace (a pocket plate described below) and a rotation side lace (a notch plate described below). As illustrated in  FIG. 1 , the SOWC  1  includes a pocket plate  11 A, a notch plate  12 A, a selector plate  13 , a snap ring  14 , and an arm  15 . 
         [0023]    As illustrated in  FIG. 1 , the pocket plate  11 A is formed in a cylindrical shape, and an annular (hollow disc-shaped) flange  111  protruding on an inner circumference side is formed at one end of the pocket plate  11 A in a direction of axis of a cylinder. The selector plate  13  and the notch plate  12 A are sequentially arranged in the flange  111 , and the snap ring  14  is lastly attached thereto, thereby assembling the pocket plate  11 A, the selector plate  13 , and the notch plate  12 A integrally. Lubricant is supplied into the SOWC  1 , that is, in between the pocket plate  11 A, the selector plate  13 , and the notch plate  12 A. The “axis” described above refers to a rotation axis of the SOWC  1  and indicated in a dot-and-dash line in  FIG. 1 . 
         [0024]    As illustrated in  FIG. 1 , a cutout  115  is formed on an outer circumference of the pocket plate  11 A. The arm  15  is inserted into the cutout  115  to couple the arm  15  with the selector plate  13 . As illustrated in  FIG. 1 , a plurality of pockets (housing recesses)  112  dented in the direction of axis (a plate thickness direction) are formed on one of the surfaces of the pocket plate  11 A, that is, on a surface of the flange  111  facing the selector plate  13 , and a plate-like strut (an engagement piece)  113  is housed in each of the pockets  112 . 
         [0025]    The pockets  112  are formed in the same number as that of notches  121  at positions corresponding to each of the notches  121  in the notch plate  12 A on the surface of the flange  111 . An elastic member  114  that biases the strut  113  toward the side of the notch plate  12 A is arranged between the bottom of the pocket  112  and the strut  113  (see  FIG. 2  described below). 
         [0026]    The strut  113  is arranged (disposed) in the respective pockets  112 . The strut  113  switches between a state in which one end of the strut  113  is raised toward the side of the notch  121  (the state of the strut  113  illustrated by a solid line in  FIG. 2 ) and a state in which the entire strut  113  including the one end is housed in the pocket  112  (the state of the strut  113  illustrated by a dot-and-dash line in  FIG. 2 ), by coaxially rotating the selector plate  13  with a rotation of the pocket plate  11 A. 
         [0027]    As illustrated in  FIG. 1 , the notch plate  12 A is formed in an annular shape (a hollow disc shape) having an external diameter same as that of the flange  111  of the pocket plate  11 A. The notch plate  12 A is arranged to face the surface of the pocket plate  11 A on which the pockets  112  are formed, and is able to rotate around the axis relative to the pocket plate  11 A. 
         [0028]    As illustrated in  FIG. 1 , a plurality of notches (engagement recesses)  121  dented in the direction of axis (the plate thickness direction) are formed on the surface facing the pocket plate  11 A (pockets  112 ) of the surfaces of the notch plate  12 A. The notches  121  are recesses into which one end of the strut  113  raised toward the side of the notch  121  is inserted respectively through each of window holes  131  in the selector plate  13 . In  FIG. 1 , only one notch  121  is illustrated by a broken line. However, in practice, the notches  121  are formed in the same number as that of the pockets  112  and the struts  113  at the positions corresponding to the pockets  112  and the struts  113 . 
         [0029]    As illustrated in  FIG. 1 , the selector plate  13  is formed in an annular shape (a hollow disc shape) having the same external diameter and the inner diameter as those of the flange  111  of the pocket plate  11 A. The selector plate  13  is arranged to face the pocket plate  11 A and the notch plate  12 A respectively. The selector plate  13  coaxially rotates with the rotation of the pocket plate  11 A by a predetermined angle around the axis to switch an engagement state and a non-engagement state as described below. 
         [0030]    The window holes  131  are formed in the selector plate  13 , passing therethrough in the direction of axis (in the plate thickness direction) at positions corresponding to the pockets  112  and the struts  113  in the pocket plate  11 A. As illustrated in  FIG. 1 , the window holes  131  are formed in the same number as that of the pockets  112  and the struts  113  at the position corresponding thereto. 
         [0031]    When the position of the window hole  131  matches the position of the pocket  112  in a circumferential direction of the SOWC  1  (see  FIG. 2  described below), one end of the strut  113  is pushed by the elastic member  114 , and raised toward the side of the notch plate  12 A (notches  121 ) through the window hole  131 . When the notch plate  12 A rotates in an engagement direction with respect to the pocket plate  11 A in the state with the one end of the strut  113  being raised toward the side of the notch  121 , the strut  113  engages with the notch  121 , and the SOWC  1  becomes an engagement state. 
         [0032]    In the engagement state, torque is transmitted between the pocket plate  11 A and the notch plate  12 A by the engagement between the strut  113  and the notch  121 . The “engagement direction” described above refers to a rotation direction in a positive direction (also referred to as “ratchet direction”) in which the one end of the strut  113  engages with the notch  121 , among the rotation directions of the notch plate  12 A, and is a direction opposite to the rotation direction illustrated in  FIG. 2 . 
         [0033]    On the other hand, in the circumferential direction of the SOWC  1 , when the position of the window hole  131  is deviated from the position of the pocket  112 , the pocket  112  is closed by a portion of the selector plate  13  where the window hole  131  is not formed, and the strut  113  is pushed to the side of the pocket  112  by the portion where the window hole  131  is not formed, and the entire strut  113  is housed in the pocket  112 . Accordingly, the SOWC  1  becomes in a non-engagement state. 
         [0034]    Furthermore, in the SOWC  1 , when the notch plate  12 A is rotating in the non-engagement direction opposite to the engagement direction with respect to the pocket plate  11 A, the SOWC  1  becomes the non-engagement state irrespective of whether the one end of the strut  113  is in the raised state or the entire strut  113  is in the state housed in the pocket  112 . 
         [0035]    In the non-engagement state, because the strut  113  does not engage with the notch  121  (the engagement between the strut  113  and the notch  121  is released), torque is not transmitted between the pocket plate  11 A and the notch plate  12 A. The “non-engagement direction” described above refers to a rotation direction in a negative direction (hereinafter, may be referred to as a “overrun direction”) in which the one end of the strut  113  does not engage with the notch  121 , among the rotation directions of the notch plate  12 A, and is the rotation direction illustrated in  FIG. 2 . 
         [0036]    The snap ring  14  is used to assemble the pocket plate  11 A, the selector plate  13 , and the notch plate  12 A integrally as described above, and as illustrated in  FIG. 1 , the snap ring  14  is formed in an annular shape (a hollow disk shape) having the same external diameter as that of the flange  111  of the pocket plate  11 A. 
         [0037]    The arm  15  is used to transmit the drive force of an actuator (not illustrated) provided externally. As illustrated in  FIG. 1 , the arm  15  is inserted into the cutout  115  of the pocket plate  11 A, and is coupled with the selector plate  13  inside the pocket plate  11 A. An apical end of the arm  15  exposed from the cutout  115  is coupled with the actuator (not illustrated). By driving the actuator, the arm  15  moves to rotate the selector plate  13 . 
         [0038]    In a conventional hybrid vehicle provided with an SOWC  101 , in the overrun state as illustrated in  FIG. 6  and  FIG. 7 , when the selector plate  13  rotates to raise the struts  113 , there is a possibility that the struts  113  collide with the notch plate  12  and the pocket plate  11  (the bottom of the pockets  112 ) alternately so as to cause short lifetime in service, wear, and the like of components such as the struts  113  and the elastic member  114 . As a state in which the selector plate  13  rotates to raise the struts  113 , such a case that the selector plate  13  is accidentally rotated due to a malfunction of the actuator (not illustrated) is included in addition to a case where the selector plate  13  is intentionally rotated by the actuator (not illustrated). 
         [0039]    A general SOWC has a ratchet function so that when the notch plate  12  rotates at a high rotation speed above a certain level in the positive direction (the ratchet direction), the strut  113  is flipped by the notch plate  12  and does not engage therewith, in order to absorb impact torque at the time of engagement. In order to ensure strength satisfying the ratchet function, the pocket plate  11 , the notch plate  12 , and the struts  113  are made of cast iron. 
         [0040]    Meanwhile, because the pocket plate  11 , the notch plate  12 , and the struts  113  are made of a material having high strength, even in the overrun state in which the notch plate  12  rotates in the negative direction (see  FIG. 6  and  FIG. 7 ), a reflection coefficient when the struts  113  are flipped by the notch plate  12  increases, thereby increasing the impact force at the time of collision. Therefore, there is a possibility that short lifetime in service of components described above occurs. 
         [0041]    In order to prevent short lifetime in service of components in the overrun state, for example, a method for reducing the number of collisions by reducing the number of notches  121  can be considered. However, if the number of notches  121  is decreased, backlash increases to increase the impact torque at the time of engagement. When durability of T/A (transaxle) built-in components is taken into consideration, this method is not preferable. 
         [0042]    Therefore, as illustrated in  FIG. 2 , the SOWC  1  according to the present embodiment is provided with an elastic body at least in one of a contact portion between the strut  113  and the notch plate  12 A and a contact portion between the strut  113  and the pocket plate  11 A, which is a contact portion that the strut  113  comes into contact therewith when the strut  113  is raised toward the side of the notch  121  by the selector plate  13  and the notch plate  12 A is rotating in the non-engagement direction (the overrun direction) with respect to the pocket plate  11 A. 
         [0043]    In the SOWC  1 , specifically as illustrated in  FIG. 2 , an elastic body  161  made of an elastic material such as rubber is provided on the side of the notch plate  12 A in the contact portion between the strut  113  and the notch plate  12 A. The elastic body  161  is provided by cutting a part of a portion of the notch plate  12 A other than the notches  121  (hereinafter, a “notch unformed portion  122 ”) and provided in the cut portion. The elastic body  161  is provided in the cut portion so as to hold the original profile (shape, outline) of the notch plate  12 A. That is, the notch plate  12 A provided with the elastic body  161  and the notch plate  12  not provided with the elastic body  161  (see  FIG. 6 ) have the same profile. Therefore, the engagement operation or the non-engagement operation of the SOWC  1  is not interrupted due to the presence of the elastic body  161 . 
         [0044]    As a method for providing the elastic body  161  in the notch plate  12 A, for example as illustrated in  FIG. 2 , such a method can be mentioned that a locking part  122   a  is formed on the side of the notch plate  12 A and a part to be locked  161   a  is formed on the side of the elastic body  161 , and by locking the locking part  122   a  to the part to be locked  161   a  to fix the both parts. However, the notch plate  12 A and the elastic body  161  can be directly bonded to each other by, for example, bonding, welding, or the like without forming the locking part  122   a  and the part to be locked  161   a.    
         [0045]    A ratchet functional part  123  for realizing the ratchet function described above is provided in the notch unformed portion  122  of the notch plate  12 A. The ratchet functional part  123  is used to flip the strut  113  when the notch plate  12 A rotates in the positive direction (the ratchet direction) at a high rotation speed above a certain level and means a gradually curved portion in the notch unformed portion  122 . The elastic body  161  is provided in a portion other than the ratchet functional part  123  in the notch unformed portion  122 , so as not to hinder the ratchet function. 
         [0046]    The SOWC  1  is also provided with an elastic body  162  made of rubber or the like on the side of the pocket plate  11 A, as illustrated in  FIG. 2 , in the contact portion between the strut  113  and the pocket plate  11 A. The elastic body  162  is provided by cutting a part of the bottom surface of the pocket  112  and provided in the cut portion. It is preferable to provide the elastic body  162  at a height at least higher than the bottom surface of the pocket  112 , and for example as illustrated in  FIG. 2 , the elastic body  162  is provided so that an upper part thereof slightly protrudes from the cut portion. 
         [0047]    As a method for providing the elastic body  162  in the pocket plate  11 A, for example as illustrated in  FIG. 2 , such a method can be mentioned that a locking part  112   a  is formed on the side of the pocket plate  11 A and a part to be locked  162   a  is formed on the side of the elastic body  162 , and by locking the locking part  112   a  to the part to be locked  162   a  to fix the both parts. However, the pocket plate  11 A and the elastic body  162  can be directly bonded to each other by, for example, bonding, welding, or the like without forming the locking part  112   a  and the part to be locked  162   a.    
         [0048]    The SOWC  1  having the configuration described above is provided with the elastic bodies  161  and  162  respectively in the contact portion between the strut  113  and the notch plate  12 A and the contact portion between the strut  113  and the pocket plate  11 A. Therefore, short lifetime in service of components such as the struts  113  can be prevented, even if the struts  113  collide with the notch plate  12 A and the pocket plate  11 A alternately in the overrun state. 
       Second Embodiment 
       [0049]    An SOWC  1 A according to a second embodiment of the present disclosure is described below. The SOWC  1 A has the same configuration as that of the SOWC  1  except for the position where an elastic body is provided. The pocket plate  11  in the SOWC  1 A is the same as that of the SOWC  101  (see  FIG. 6 ). 
         [0050]    As illustrated in  FIG. 3 , the SOWC  1 A is provided with an elastic body  161  made of rubber or the like on the side of the notch plate  12 A in the contact portion between strut  113 A and the notch plate  12 A. The configuration of the elastic body  161  is the same as that of the first embodiment (see  FIG. 2 ). 
         [0051]    The SOWC  1 A is also provided with an elastic body  163  made of rubber or the like on the side of the strut  113 A in the contact portion between the strut  113 A and the pocket plate  11 . The elastic body  163  is provided by cutting a part of the strut  113 A on the side of the pocket  112  and provided in the cut portion. The elastic body  163  is provided in the cut portion so as to hold an original profile (shape, outline) of the strut  113 A. That is, the strut  113 A provided with the elastic body  163  and the strut  113  not provided with the elastic body  163  (see  FIG. 6 ) have the same profile. Therefore, the engagement operation or the non-engagement operation of the SOWC  1 A is not interrupted due to the presence of the elastic body  163 . 
         [0052]    For the sake of convenience of description, the bottom surface of the pocket  112  is expressed by a flat surface in  FIG. 3 . However, in practice, the pocket  112  is provided with irregularities on the bottom surface thereof. The strut  113 A is configured such that when the strut  113 A collides with the bottom surface of the pocket  112 , the portion provided with the elastic body  163  collides with the bottom surface (convex portions formed thereon) of the pocket  112 . 
         [0053]    The SOWC  1 A having the configuration described above is provided with the elastic bodies  161  and  163  respectively in the contact portion between the strut  113 A and the notch plate  12 A and the contact portion between the strut  113 A and the pocket plate  11 . Therefore, short lifetime in service of components such as the struts  113 A can be prevented, even if the struts  113 A collide with the notch plate  12 A and the pocket plate  11  alternately in the overrun state. 
       Third Embodiment 
       [0054]    An SOWC  1 B according to a third embodiment of the present disclosure is described below. The SOWC  1 B has the same configuration as that of the SOWC  1  except for the position where the elastic body is provided. The notch plate  12  in the SOWC  1 B is the same as that of the SOWC  101  (see  FIG. 6 ). 
         [0055]    As illustrated in  FIG. 4 , the SOWC  1 B is provided with an elastic body  164  on the side of a strut  113 B in the contact portion between the strut  113 B and the notch plate  12 . The elastic body  164  is provided by cutting a part of the strut  113 B on the side of the notch plate  12  and provided in the cut portion. The elastic body  164  is provided on the cut portion side so as to hold an original profile (shape, outline) of the strut  113 B. That is, the strut  113 B provided with the elastic body  164  and the strut  113  not provided with the elastic body  164  (see  FIG. 6 ) have the same profile. Therefore, the engagement operation or the non-engagement operation of the SOWC  1 B is not interrupted due to the presence of the elastic body  164 . 
         [0056]    The SOWC  1 B is also provided with an elastic body  162  on the side of the pocket plate  11 A in the contact portion between the strut  113 B and the pocket plate  11 A. The configuration of the elastic body  162  is the same as that of the first embodiment (see  FIG. 2 ). 
         [0057]    The SOWC  1 B having the configuration described above is provided with the elastic bodies  164  and  162  respectively in the contact portion between the strut  113 B and the notch plate  12  and the contact portion between the strut  113 B and the pocket plate  11 A. Therefore, short lifetime in service of components such as the struts  113 B can be prevented, even if the struts  113 B collide with the notch plate  12  and the pocket plate  11 A alternately in the overrun state. 
       Fourth Embodiment 
       [0058]    An SOWC  1 C according to a fourth embodiment of the present disclosure is described below. The SOWC  1 C has the same configuration as that of the SOWC  1  except for the position where the elastic body is provided. 
         [0059]    As illustrated in  FIG. 5 , the SOWC  1 C is provided with an elastic body  164  on the side of a strut  113 C in the contact portion between the strut  113 C and the notch plate  12 . The configuration of the elastic body  164  is the same as that of the third embodiment described above (see  FIG. 4 ). 
         [0060]    The SOWC  1 C is also provided with an elastic body  163  on the side of the strut  113 C in the contact portion between the strut  113 C and the pocket plate  11 . The configuration of the elastic body  163  is the same as that of the second embodiment described above (see  FIG. 3 ). 
         [0061]    The SOWC  1 C having the configuration described above is provided with the elastic bodies  164  and  163  respectively in the contact portion between the strut  113 C and the notch plate  12  and the contact portion between the strut  113 C and the pocket plate  11 . Therefore, short lifetime in service of components such as the struts  113 C can be prevented, even if the struts  113 C collide with the notch plate  12  and the pocket plate  11  alternately in the overrun state. 
         [0062]    The selectable one-way clutch according to the present disclosure has been specifically described above in the modes for carrying out the present disclosure. However, the spirit of the present disclosure is not limited to the descriptions of the embodiments and should be interpreted widely based on the descriptions of the claims. Further, needless to mention that various modifications and changes based on the descriptions are included in the spirit of the present disclosure. 
         [0063]    For example, in the SOWC  1  described above (see  FIG. 2 ), the elastic body  161  is provided on the side of the notch plate  12 A in the contact portion between the strut  113  and the notch plate  12 A, and the elastic body  162  is provided on the side of the pocket plate  11 A in the contact portion between the strut  113  and the pocket plate  11 A. However, only the elastic body  161  is provided on the side of the notch plate  12 A without providing the elastic body  162  on the side of the pocket plate  11 A. 
         [0064]    Furthermore, in the SOWC  1  (see  FIG. 2 ) described above, the elastic body  161  is provided on the side of the notch plate  12 A in the contact portion between the strut  113  and the notch plate  12 A, and the elastic body  162  is provided on the side of the pocket plate  11 A in the contact portion between the strut  113  and the pocket plate  11 A. However, only the elastic body  162  is provided on the side of the pocket plate  11 A without providing the elastic body  161  on the side of the notch plate  12 A. 
         [0065]    In the SOWC  1 A (see  FIG. 3 ) described above, the elastic body  161  is provided on the side of the notch plate  12 A in the contact portion between the strut  113 A and the notch plate  12 A, and the elastic body  163  is provided on the side of the strut  113 A in the contact portion between the strut  113 A and the pocket plate  11 . However, only the elastic body  163  is provided on the side of the strut  113 A without providing the elastic body  161  on the side of the notch plate  12 A. 
         [0066]    Furthermore, in the SOWC  1 B (see  FIG. 4 ) described above, the elastic body  164  is provided on the side of the strut  113 B in the contact portion between the strut  113 B and the notch plate  12 , and the elastic body  162  is provided on the side of the pocket plate  11 A in the contact portion between the strut  113 B and the pocket plate  11 A. However, only the elastic body  164  is provided on the side of the strut  113 B without providing the elastic body  162  on the side of the pocket plate  11 A. 
         [0067]    According to an embodiment of the present disclosure, because the selectable one-way clutch is provided with an elastic body at least in one of a contact portion between an engagement piece and a notch plate and a contact portion between an engagement piece and a pocket plate, impact force at the time of collision can be absorbed by the elastic body, thereby enabling to prevent short life in service of components such as struts. 
         [0068]    According to an embodiment of the present disclosure, the selectable one-way clutch according to the present disclosure is provided with an elastic body on the side of the notch plate, in the contact portion between the engagement piece and the notch plate that come into contact with each other when the engagement piece is in the raised state toward the side of the engagement recess and the notch plate is rotating in the non-engagement direction with respect to the pocket plate. 
         [0069]    According to an embodiment of the present disclosure, because the selectable one-way clutch is provided with the elastic body in the contact portion between the engagement piece and the notch plate, impact force at the time of collision can be absorbed by the elastic body, thereby enabling to prevent short life in service of components such as the struts. 
         [0070]    According to an embodiment of the present disclosure, because the selectable one-way clutch is provided with the elastic body in the contact portion between the engagement piece and the notch plate, impact force at the time of collision can be absorbed by the elastic body, thereby enabling to prevent short life in service of components such as the struts. 
         [0071]    According to an embodiment of the present disclosure, because the selectable one-way clutch is provided with the elastic body in the contact portion between the engagement piece and the pocket plate, impact force at the time of collision can be absorbed by the elastic body, thereby enabling to prevent short life in service of components such as the struts. 
         [0072]    According to an embodiment of the present disclosure, because the selectable one-way clutch is provided with the elastic body in the contact portion between the engagement piece and the pocket plate, impact force at the time of collision can be absorbed by the elastic body, thereby enabling to prevent short life in service of components such as the struts. 
         [0073]    According to an embodiment of the present disclosure, short life in service of components can be prevented even if an engagement piece collides with a notch plate and a pocket plate alternately in an overrun state. 
         [0074]    Although the disclosure has been described with respect to specific embodiments for a complete and clear disclosure, the appended claims are not to be thus limited but are to be construed as embodying all modifications and alternative constructions that may occur to one skilled in the art that fairly fall within the basic teaching herein set forth.