Abstract:
A one-way clutch device comprises a plurality of torque transmission members interposed between an inner race element and an outer race element for performing torque transmission therebetween only during one-way relative rotation. A cage has a pair of flanges for holding the torque transmission members therebetween and a plurality of coupling columns for coupling the paired flanges together. The coupling columns of the cage are fixed to fixing portions provided on an inner peripheral side and an outer peripheral side of the flanges.

Description:
This application claims the benefit of Japanese Patent applications No. 2003-039933 and No. 2003-173720 which are hereby incorporated by reference. 
   BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to a one-way clutch device which is assembled in a starter apparatus, or the like, for an automatic two-wheeled vehicle, and a method for manufacturing the same. 
   2. Related Background Art 
   A starter apparatus for an automobile is additionally provided with a one-way clutch device for performing torque transmission from an electric motor side to an internal combustion engine side only, in order to prevent overrun of the electric motor after the internal combustion engine is started. As a one-way clutch device of this type, one type is dominantly used in which clutch elements such as torque transmission rollers, cam surfaces and a spring is interposed between an inner race element and an outer race element, and these clutch elements are accommodated in and retained by a cage which is formed of a steel plate or synthetic resin (see the Japanese Utility Model Registration No. 2574315 (page 3, FIG. 1), the Japanese Patent Publication No. 56-41847 (page 3, FIG. 1), the Japanese Utility Model Publication No. 49-20603 (page 2, FIG. 6) and the Japanese Patent Application Laid-Open No. 11-117955 (page 1, FIG. 2, particularly), for example). 
   Also, there is disclosed in the Japanese Patent Application Laid-Open No. 11-117955 a one-way clutch device in which a cage formed of an elastically deformable material comprises a cylindrical portion and a flange, the flange has a plurality of clapper pieces which are elastically deformable and extended substantially in a circumferential direction, and the clapper pieces are inserted in flange receiving grooves formed on the outer race by the use of the elastic deformation of the clapper pieces to be fixed in the axial direction. That is, the flange is provided with a small-diameter portion and the clapper pieces which are extended substantially in the circumferential direction to be elastically deformable formed on the same flat surface thereof. On the outer race, there are formed flange receiving grooves each having the diameter larger than that of the small-diameter portion of the flange and smaller than that of the clapper piece. When each of the clapper pieces is flexed to be moved to the position of the flange receiving groove, the elastically deformable clapper piece is, with the property of returning into its original form, fitted into the flange receiving groove, whereby the one-way clutch is retained at that position in the axial direction. 
   The conventional one-way clutch device described above functions well without any trouble in a starter apparatus for a four-wheeled vehicle in which the maximum number of rotations of the internal combustion engine is comparatively low which is, e.g., approximately 6,000rpm . However, when this clutch device is used in a starter apparatus for an automatic two-wheeled vehicle in which the maximum number of rotations of the internal combustion engine is comparatively high which is, e.g., approximately 15,000 rpm, such a problem as described below may be brought about. That is, for example, during the operation of the internal combustion engine, a constituent member of the one-way clutch device is affected by the centrifugal force which follows the rotation. In the case of an automatic two-wheeled vehicle, the centrifugal force becomes very large due to the high maximum number of rotations, so that coupling columns of the cage are sometimes deformed to spread in the outer diameter direction. Moreover, since the centrifugal force acting on the spring becomes larger in the same manner, the spring may come off the cage such that its function of urging the torque transmission rollers can not be performed. 
   There is another fear that the cage and a member and the like assembled in the cage may fall out from the outer race member (outer race element) at the time of conveyance prior to the installation thereof to the main body of the two-wheeled vehicle, an automatic transmission, etc., 
   In the one-way clutch disclosed in the Japanese Patent Application Laid-Open No. 11-117955, the elastically deformable clapper pieces are fitted into the flange receiving groove, with the property of returning into its original form, so that the one-way clutch is retained at that position in the axial direction. For this reason, it is possible to prevent fall out of parts such as a cage. However, the structure disclosed in the Japanese Patent Application Laid-Open No. 11-117955 mainly depends on the elastic deformation of the clapper pieces, which is not always advantageous to prevention of a fall out of the cage or the like parts. 
   Further, when the constituent parts of the cage are assembled to complete the cage, the assembling performance of each part is not always satisfactory. For example, when the detention piece is to be fitted in the recess, the detention may be hooked by the recess. 
   SUMMARY OF THE INVENTION 
   The present invention has been contrived taking the situation described above into consideration, and an object of the invention is to provide a one-way clutch device with the intention of improving the strength of the coupling columns, preventing a fall out of a spring, or the like, and further with the intention of preventing a fall out of the cage, or the like, from the outer race in order to improve the assembling performance of each constituent part of the cage, and a method for manufacturing such a one-way clutch device. 
   In order to solve the above-described problems, according to a first aspect of the present invention, there is provided a one-way clutch device comprising a plurality of torque transmission members interposed between an inner race element and an outer race element for performing torque transmission between the inner race element and the outer race element only during one-way relative rotation, and a cage having a pair of flanges for holding these torque transmission members therebetween and a plurality of coupling columns for coupling the paired flanges together, wherein the coupling columns of the cage may be fixed to fixing portions provided at least at two positions on the inner peripheral side and the outer peripheral side of the flanges. 
   In a first mode of the present invention, in the one-way clutch device according to the first aspect, at least one of the fixing portions may be a hole or a recess, and a caulking portion to be fitted in the hole or recess to be caulked may be formed in an end portion of the coupling column. 
   In a second mode of the present invention, in the one-way clutch device of the first mode, at least one of the fixing portions may be a hole or a recess, and a detention portion to be fitted in the hole or recess may be formed in an end portion of the coupling column. 
   In a third mode of the present invention, in the one-way clutch device of the second mode, a guide part may be formed on the detention portion for guiding the detention portion to be fitted into the recess or hole. 
   In a fourth mode of the present invention, in the one-way clutch device of the third mode, the guide part may be formed by chamfering or beveling the tip end of the detention portion. 
   In a fifth mode of the present invention, in the one-way clutch device according to either one of the second to fourth modes, the tip end of the detention portion may be protruded from the flange. 
   In a sixth mode of the present invention, in the one-way clutch device of the fifth mode, an amount of projection of the detention portion may be smaller than that of the caulking portion. 
   In a seventh mode of the present invention, the one-way clutch device described above may further comprise springs for urging respectively the torque transmission members in the direction of torque transmission, wherein a fixed end of each spring may be held between the flange and the coupling column between the two fixing portions. 
   In an eighth mode of present invention, in the one-way clutch device described above, each coupling column may be extended from one of the flanges and may be fixed to the other of the flanges. 
   According to a second aspect of the present invention, in one-way clutch device comprising an inner race element, an outer race element disposed to be coaxial and relatively rotatable with this inner race element, a plurality of cam surfaces formed on either one of the outer peripheral surface of the inner race element and the inner peripheral surface of the outer race element, a cylindrical surface formed on the other of the outer peripheral surface of the inner race element and the inner peripheral surface of the outer race element, a plurality of torque transmission rollers interposed between the cam surfaces and the cylindrical surface, springs for urging the respective torque transmission rollers in the direction of torque transmission, and a cage for retaining the torque transmission rollers and the springs, the cage being constituted by two metal plates each in a substantially annular form, a plurality of coupling columns bent up substantially perpendicularly from one of the metal plates being fixed to the other of the metal plates, and the torque transmission rollers and the springs being retained between the adjacent coupling columns, the coupling column may have an outer peripheral portion substantially along the tangential direction of the outer race element, an inner peripheral portion substantially along the tangential direction of the inner race element, and an inclined portion for coupling the outer peripheral portion and the inner peripheral portion together; a connection piece protruded from an end surface of the outer peripheral portion may be fixed to the other of the metal plates; and a detention piece protruded from an end surface of the inner peripheral portion may be fitted in a recess formed on the other of the metal plates. 
   In a ninth mode of the present invention, in the one-way clutch device according to the second aspect, the fixing may be fitting of the connection piece in the hole or recess formed on the other of the metal plates to be caulked. 
   In a tenth mode of the present invention, in the one-way clutch device according to the second aspect, the fixed end of the spring may be held by and between said inclined portion and the other of said metal plates. 
   In an eleventh mode of the present invention, in the one-way clutch device according to the second aspect comprising outer and inner races which are arranged coaxially and a cage provided with torque transmission members and biasing springs for urging the respective torque transmission members between the outer and inner races, the cage may have a flange which is provided with an engagement projection; and a fit groove into which the engagement projection may be fitted is formed on at least one of the outer and inner races. 
   In a twelfth mode of the present invention, in the one-way clutch device of the eleventh mode, a plurality of the engagement projections may be provided on the circumference at regular intervals. 
   In a thirteenth mode of the present invention, in the one-way clutch device of the tenth to eleventh modes, the fit grooves may be formed in a substantially annular form. 
   In a fourteenth mode of the present invention, in the one-way clutch device according to either one of the tenth to thirteenth mode, the engagement projections may be formed on the outer periphery of the flange and the fit grooves may be formed on the inner periphery of the outer race. 
   In a fifteenth mode of the present invention, in the one-way clutch device according to either one of the tenth to fourteenth mode, the inner element or the outer element may be provided with a guide part for guiding the engagement projections to be fitted in the fit grooves when the cage is assembled. 
   According to a third aspect of the present invention, there is provided a method for manufacturing a one-way clutch device comprising an inner race element, an outer race element disposed to be coaxial and relatively rotatable with the inner race element, a plurality of cam surfaces formed on either one of the outer peripheral surface of the inner race element and the inner peripheral surface of the outer race element, a cylindrical surface formed on the other of the outer peripheral surface of the inner race element and the inner peripheral surface of the outer race element, a plurality of torque transmission rollers interposed between the cam surfaces and the cylindrical surface, springs for urging the torque transmission rollers in the direction of torque transmission, and a cage for retaining the torque transmission rollers and the springs, the cage being constituted by two metal plates each in a substantially annular form, a plurality of coupling columns bent up substantially perpendicularly from one of the metal plates being fixed to the other of the metal plates, and the torque transmission rollers and the springs being retained between the adjacent coupling columns, which manufacturing method comprising: a step of blanking a first work serving as one of the metal plates from a metal plate material; a step of bending coupling column portions of the first work to have a predetermined cross section; a step of obtaining a first metal plate by bending up the coupling column portions of the first work; a step of blanking the other of the metal plates from a metal plate material together with a fixing hole or recess; a step of attaching an end of each spring to the corresponding coupling column of the first metal plate; and a step of fixing the coupling columns of the first metal plate to the second metal plate. 
   In the method for manufacturing a one-way clutch device according to the present invention, the step of fixing the coupling columns of the first metal plate to the second metal plate may be carried out by fitting and caulking a connection piece formed to be protruded on an end portion of each coupling column into the hole or recess. 
   In the method for manufacturing a one-way clutch device according to the present invention, the step of fixing the coupling columns of the first metal plate to the second metal plate may be carried out by fitting and fastening a detention piece formed to be protruded at an end portion of each coupling column in the hole or recess. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a front view of a one-way clutch device according to an embodiment of the present invention; 
       FIG. 2  is a cross-sectional view taken along line A—A in  FIG. 1 ; 
       FIG. 3  is a front view of a cage according to the first embodiment of the present invention; 
       FIG. 4  is an enlarged view of an essential portion of the cage according to the first embodiment of the present invention; 
       FIG. 5  is a plan view of an accordion spring; 
       FIG. 6  is a front view of a work; 
       FIG. 7  is an explanatory view for illuminating a treatment process of the work; 
       FIG. 8  is an explanatory view for illuminating the treatment process of the work; 
       FIG. 9  is a front view of a second flange; 
       FIG. 10  is an explanatory view for illuminating an assembling process of the cage; 
       FIG. 11  is an explanatory view for illuminating an assembling process of the cage; 
       FIG. 12  is a front view of a one-way clutch device according to a second embodiment of the present invention; 
       FIG. 13  is a cross-sectional view taken along line B—B in  FIG. 12 ; 
       FIG. 14  is a partially exploded front view of the cage shown in  FIG. 12 ; 
       FIG. 15  is an enlarged view for showing an essential portion of the cage shown in  FIG. 12 ; 
       FIG. 16  is a developed view of the cage on the first flange side; 
       FIG. 17  is a front view of the cage on the second flange side; 
       FIG. 18  is a plan view of an urging spring (accordion spring); 
       FIG. 19  is an enlarged cross-sectional view of a portion C in  FIG. 13 ; 
       FIG. 20  is an enlarged view for showing a detention piece and a detention portion of a recess, seen from the inner diameter side outwardly in the radial direction; and 
       FIG. 21  is an enlarged view for showing the detention piece and the detention portion of the recess, seen from the front. 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   The present invention will be specifically described below with reference to the drawings. 
   (First Embodiment) 
     FIG. 1  is a front view for showing a first embodiment of a one-way clutch device according to the present invention, and  FIG. 2  is a cross-sectional view taken along line A-A in  FIG. 1 . Also,  FIG. 3  is a front view of a cage, and  FIG. 4  is an enlarged view of an essential portion of the cage. 
   As shown in  FIG. 1  and  FIG. 2 , the one-way clutch device  1  of the present invention is comprised of an inner race member (inner race element)  3 , an outer race member (outer race element)  7  which is disposed coaxially with and relatively rotatable with respect to the inner race member  3  and is provided with a plurality of cam surfaces  5  (six in the present embodiment) formed on the inner periphery thereof, a plurality of torque transmission rollers  9  (six in the present embodiment) which are interposed between the inner race member  3  and the outer race member  7 , accordion springs  11  for urging respectively the torque transmission rollers  9  in the direction of torque transmission, and a cage  13  formed of a steel plate. 
   In the case of the present embodiment, the inner race member  3  is coupled to a start motor which is not shown in the drawing while the outer race member  7  is coupled to a generator which is not shown in the drawing. A tapped hole  15  is formed on the outer race member  7  and is to be used to fasten the outer race member  7  to the generator. 
   As shown in  FIG. 3  and  FIG. 4 , the cage  13  is comprised of a first flange (one of metal plates)  21  and a second flange (the other of the metal plates)  23  assembled therein. The both flanges are formed of steel plates by pressing. The accordion springs  11  are retained by the respective coupling columns  25  extended from the first flange  21  and by the second flange  23 . 
   Each coupling column  25  comprises an outer peripheral portion  27  extended substantially along the tangential direction of the outer race member  7 , an inner peripheral portion  29  substantially along the tangential direction of the inner race member  3 , and an inclined portion  31  for coupling the outer peripheral portion  27  and the inner peripheral portion  29  together. Then, connection pieces  33  protruded from an axial end surface of the outer peripheral portion  27  are fitted in the respective through holes  35  formed on the second flange  23  and caulked thereon, and detention pieces  37  protruded from an axial end surface of the inner peripheral portion  29  are fitted in the respective recesses  39  formed on the second flange  23  to be detained. 
   As shown in  FIG. 5 , each accordion spring  11  comprises a pressing portion  41  for urging the corresponding torque transmission roller  9  and a fixed end  43  which is retained by the corresponding coupling column  25 . The fixed end  43  of each accordion spring  11  is held by and between the inclined portion  31  and the second flange  23 , so as to prevent the accordion spring  11  from falling out in the radial direction by the connection pieces  33  and the detention pieces  37 . 
   Description will be made below on a method for manufacturing the one-way clutch device of the present embodiment. 
   A manufacturer blanks a work  51  shown in  FIG. 6  from a steel plate material by the use of a pressing machine. The work  51  is constituted by six coupling column portions  55  which serve as coupling columns  25  formed on the outer peripheral side of a flange portion  53  serving as the first flange portion  21 . 
   Upon completion of the blanking of the work  51 , the manufacturer executes a bending process on the coupling column portions  55  by the use of the pressing machine, as shown in  FIG. 7 , thereby forming the inclined portions  31 , each coupling the outer peripheral portion  27  and the inner peripheral portion  29  together. The connection piece  33  is formed to be protruded from an end of the outer peripheral portion  27 , and the detention piece  37  is protruded from an end of the inner peripheral portion  29 . The manufacturer then bends up the coupling column portions  55  by the pressing machine, thereby completing the first flange  21  having the coupling columns  25  perpendicularly thereto. 
   Additionally, the manufacturer blanks the second flange  23  shown in  FIG. 9  from the steel plate material by the use of a pressing machine. The second flange  23  is formed with six through holes  35  and twelve recesses  39  on the inner peripheral end thereof. 
   Upon completion of the first flange  21  and the second flange  23 , the manufacturer fits the connection pieces  33  of the coupling columns  25  into the respective through holes  35  of the second flange  23  and the detection pieces  37  into the respective recesses  39  in a state that the fixed end  43  of each accordion spring  11  has been inserted on the corresponding inclined portion  31  of the coupling column  25 , as shown in  FIG. 10 . After that, as shown in  FIG. 11 , the manufacturer caulks the connection pieces  33  protruded through the respective through holes  35  to thereby complete the cage  13 . In the present embodiment, since there are arranged twelve recesses  39 , the directionality (either the surface or the back) of the second flange  23  disappears so as to make the assembling work easier. 
   Upon completion of the cage  13 , the manufacturer assembles the torque transmission rollers  9  in the cage  13  and then installs the cage  13  between the inner race member  3  and the outer race member  7 , thereby completing the manufacturing process. 
   Each of the coupling columns  25  of the cage  13  in the present embodiment has a substantially Z-shaped cross section consisting of the outer peripheral portion  27 , the inner peripheral portion  29  and the inclined portion  31 , so that the strength and the rigidity thereof become very high. For this reason, there is no fear that the coupling column  25  may be deformed by the centrifugal force even when the one-way clutch device is used for an automatic two-wheeled vehicle. Also, since the fixed end  43  of each accordion spring  11  is held or sandwiched by and between the inclined portion  31  and the second flange  23  and further the accordion spring  11  is prevented from falling out in the radial direction by the connection piece  33  and the detention piece  37 , there is no fear at all that the accordion spring  11  may fall out as a result of centrifugal force. 
   (Second Embodiment) 
     FIG. 12  is a front view of a one-way clutch device according to a second embodiment of the present invention,  FIG. 13  is a cross-sectional view taken along line B—B in  FIG. 12 , and  FIG. 14  is a partially exploded front view of the cage shown in  FIG. 12 .  FIG. 15  is an enlarged view for showing an essential portion of the cage shown in  FIG. 12 . 
     FIG. 16  is a developed view of the cage on the first flange side.  FIG. 17  is a front view of the cage on the second flange side.  FIG. 18  is a plan view of an urging spring which is an accordion spring. 
     FIG. 19  is an enlarged cross-sectional view of the portion C in  FIG. 13 .  FIG. 20  is an enlarged view for showing a detention piece and a detention portion of a recess, seen from the inner diameter side outwardly in the radial direction.  FIG. 21  is an enlarged view for showing the detention piece and the detention portion of the recess, seen from the front. 
   The second embodiment is obtained by improving the first embodiment described above, and description of the arrangements and effects common to the both embodiments will be omitted. Only different points will be described. 
   In the first embodiment described above, it is feared that, during conveyance preceding to the assembling in the main body of a two-wheeled vehicle, an automatic transmission, or the like, the cage  13 , constituent parts assembled in the cage  13 , or the like, may drop out from the outer race member  7 . 
   For such a reason, in the second embodiment, as shown in the portion C in  FIG. 13  and in  FIG. 19 , a circumferential fit groove  60  which is substantially annular and narrow is provided on the inner peripheral end edge of the outer race member  7 . 
   Additionally, as shown in  FIG. 14  and  FIG. 17 , a plurality of engagement projections  61  are formed on the outer peripheral end edge of the second flange  23  of the cage  13 , each to be fitted in fit groove  60  and engaged therewith. 
   As shown in  FIG. 19 , it is arranged such that, when the cage  13  is attached to the outer race member  7  for assembling, that is, when the second flange  23  is inserted in the axial direction, these plurality of engagement projections  61  are fitted in the fit groove  60  (circumferential groove) and are engaged therewith. 
   Note that, when this fitting is carried out, the second flange  23  is slightly flexed. Also, as shown in  FIG. 19 , a chamfered or beveled portion  62  serving as a guide part is formed on the inner peripheral end surface of the outer race member  7  in such a manner that, when the second flange  23  is inserted in the axial direction, the engagement projections  61  are smoothly moved on the inner peripheral end surface of the outer race member  7  to be guided into the circumferential fit groove  60 . 
   As described above, since the plurality of engagement projections  61  are fitted in the circumferential groove  60 , it is possible to restrict a movement of the cage  13  in the axial direction by detaining the cage  13  at that position in the axial direction. Also, since the second flange  23  and the engagement projections  61  are elastically deformed comparatively less, compared with structure disclosed in the Japanese Patent Application Laid-Open No. 11-117955, the cage  13  can be detained at that position in the axial direction without fail, and consequently, the cage  13 , or the like, can be prevented from getting out of the outer race member  7 . 
   Also, in the first embodiment described above, when the cage  13  is completed by assembling all the constituent parts of the case  13 , there is a probability that the assembling performance of each part is not always satisfactory so that the detention piece  37  is, for example, when it is to be fitted in the recess  39 , caught or hooked by the recess  39  without being fitted therein. 
   In order to prevent such a trouble, in the second embodiment, a chamfered or beveled portion  70  serving as a guide for guiding the detention piece  37  to be fitted into the recess  39  is provided in the tip end portion of the detention piece  37 . 
   With such an arrangement, the tip end portion of the detention piece  37  can be fitted in the recess  39  easily and the detention piece  37  can be prevented from being hooked or caught by the recess  39 , whereby the assembling performance of each part of the cage can be remarkably improved. 
   The guide part  70  described above is formed by chamfering or beveling the tip end portion of the detention piece  37 . However, it is possible to provide any other contrivance, and the guide part may be in an inclined, arcuate, or any other form so long as the tip end portion is not hooked nor caught by the end surface of the recess  39 . Also, it is possible to obtain the same effect by properly altering the surface roughness, or the like, of the guide part. Further, it is possible to prevent the tip end portion from being hooked or caught by the end surface of the recess  39  by properly setting a detention space between the detention piece  37  and the recess  39 . Also, as shown in  FIG. 15  and  FIG. 20 , each detention piece  37  is slightly protruded from the second flange  23 . The amount of this projection is made smaller than that of the connection piece  33  (the caulking portion or the thick plate portion), as shown in  FIG. 15 . With such an arrangement, it is possible to securely attain a sufficient engagement or abutment between the detention piece  37  and the recess  39 . 
   Note that the assembling performance may be improved by disposing this chamfered or beveled guide part  70  on the recess  39  of the second flange  23 . In this case, however, the degree of engagement between the recess  39  and the detention piece  37  becomes lower unless the detention piece  37  takes a form in compliance with the guide part  70 . Thus, the working process becomes complicated correspondingly. As a result, the method illustrated in the respective drawings above is superior in terms of the productivity. 
   The specific embodiments of the present invention are as described above. However, the present invention is not limited to these embodiments. For example, in the foregoing embodiments, the present invention is applied to the one-way clutch device of a roller type which has cam surfaces on the outer race member. However, the present invention can be applied to a one-way clutch device which has cam surfaces on the inner race member, or has steel balls as the torque transmission members, instead of the torque transmission rollers. In addition, a metal plate other than a steel plate such as a brass plate may be used for the first flange and the second flange. Further, the number of the torque transmission members, the specific forms of the first and second flanges, the entire structure of the one-way clutch device, etc., may be properly altered within the scope and spirit of the present invention. 
   According to the one-way clutch device of the present invention, the strength and the rigidity of the coupling columns of the case become very high, so that the coupling columns are not likely to be deformed due to the centrifugal force even when the one-way clutch device is used in an automatic two-wheeled vehicle. Additionally, the accordion spring is, since being securely retained by the coupling column and the second flange at the fixed end thereof, not likely to fall out due to centrifugal force. Thus, the one-way clutch device can maintain the stable function even if it is used for a long term. 
   It is also possible to prevent the cage, or the like, from falling out of the outer race, and moreover, the assembling performance of each constituent part of the cage can be improved.