Patent Publication Number: US-2005115339-A1

Title: Starter

Description:
BACKGROUND OF THE INVENTION  
      1. Field of the Invention  
      The present invention relates to a starter which is constructed so that the inertial rotation of a motor is rapidly terminated after the energization of the motor has been shut off after the start of an engine, and also relates to an improvement in a brake mechanism thereof.  
      2. Description of the Related Art  
       FIG. 1  is a sectional view of an essential portion of one embodiment of a starter in accordance with the present invention. By using  FIG. 1 , a relation between an electromagnetic switch, motor, pinion shift lever, pinion, and clutch in the starter is explained first.  
      In the figure, reference numeral  1  denotes a starter,  2  denotes an electromagnetic switch,  3  denotes a pinion,  4  denotes a clutch outer,  5  denotes a pinion shift lever, and  6  denotes a motor.  
      In  FIG. 1 , the electromagnetic switch  2  includes a driving coil  22  wound on a hollow cylindrical coil bobbin  21 , a fixed iron core  23  fixed in the hollow space of the coil bobbin  21 , a movable iron core  24  supported movably in the hollow space of the coil bobbin  21 , a driving shaft  25  which is fixed to the movable iron core  24  and has an engagement portion  25   a  at one end and a movable contact portion  26  on the other hand, terminals  28 ,  28 , and fixed contacts  27 ,  27  connected to the terminals  28 .  
      In  FIG. 1 , on the upside of the centerline of the electromagnetic switch  2 , a state is shown in which the driving coil  22  is in a de-energized state so that the driving shaft  25  is located on the left-hand side in the figure, and the movable contact portion  26  is not in contact with the fixed contact  27 . On the downside of the centerline thereof, a state is shown in which the driving coil  22  is in an energized state so that the driving shaft  25  is located on the right-hand side in the figure, and the movable contact portion  26  is in contact with the fixed contact  27 .  
      The electromagnetic switch  2  is configured as described below. When an ignition switch (not shown) of a vehicle is turned on, the driving coil  22  is energized by a battery (not shown), and thus the driving shaft  25  is moved to the right-hand side in the figure. Thereby, a forked head portion of the pinion shift lever  5  engaged with the engagement portion  25   a  is turned in the clockwise direction with a lever pin  73  being a support point as indicated by the broken line in the figure. A roller  56  provided in a forked leg portion of the pinion shift lever  5  moves a shifter portion  42  connectingly provided on the clutch outer  4  in the left direction in the figure, and the pinion  3  fixed to a clutch inner  4   a  via a clutch roller  4   b  is pushed out to the left-hand side in the figure while being rotated slowly by the action of a spline cylindrical portion  41  and helical splines  44 . When the pinion  3  meshes with a ring gear, not shown, on the engine side, the motor  6  is started by the contact of the movable contact portion  26  of the electromagnetic switch  2  with the fixed contacts  27 ,  27 , by which an engine is started.  
      In  FIG. 1 , on the upside of the centerline of the pinion  3 , clutch outer  4 , and motor  6 , a state is shown in which the pinion  3  is not projected, and on the downside of the centerline thereof, a state is shown in which the pinion  3  is projected.  
      After the not illustrated engine has been started, the driving coil  22  of the electromagnetic switch  2  is de-energized, and thereby the movable iron core  24  is returned to the left-hand side in the figure. The movable contact portion  26  is separated from the fixed contacts  27 ,  27 , so that the power to the motor  6  is shut off, and also the pinion shift lever  5  is returned to the original position as indicated by the solid line in the figure.  
      Reference numeral  17  denotes a rear bracket for the motor  6 ,  18  denotes a center bracket for the motor  6 , and  19  denotes a brake plate. Also, a collar portion  43  of the clutch outer  4  has a construction such that when the pinion  3  returns to the not-projected state, the end surface of the collar portion  43  comes into contact with the brake plate  19  that partially overlaps with an output shaft of the motor  6  in a ring form to terminate the inertial rotation of the motor  6  via the brake plate  19 . This construction in which when the pinion  3  returns to the not-projected state, the end surface of the collar portion  43  comes into contact with the brake plate  19  to terminate the inertial rotation of the motor  6  is a structural portion of the present invention. This structural portion will be explained in more detail later with reference to  FIGS. 2 through 5 .  
      In the above explanation, the relation between the electromagnetic switch  2 , pinion  3 , clutch outer  4 , pinion shift lever  5 , and motor  6  in the starter  1  has been described. Hereunder, a construction of a stopper mechanism against the axial movement of the pinion  3  used in the conventional starter, and a construction of a stopper mechanism of a clutch using a helical spline connection will be explained.  
      The applicants of the present invention have proposed a starter described in Japanese Patent Laid-Open No. 2003-214304. The starter described in said Japanese Patent Laid-Open No. 2003-214304 is explained with reference to  FIGS. 6 and 7 .  FIG. 6  is a partially sectional view of a portion near a clutch and a reducer of a conventional starter, and  FIG. 7  is a sectional view taken along the line A-A of  FIG. 6 .  
      In  FIGS. 6 and 7 , an armature shaft  153  of a motor  152  constituting the starter is coaxially connected to an output shaft  155  via a reducer  154 , and the output shaft  155  is rotatably supported on a center bracket  157  via a bearing  156 .  
      The reducer  154  is a planetary gear speed reducing mechanism made up of a sun gear  158  provided on the armature shaft  153 , a ring-shaped internal gear  159  which is arranged at the outer periphery in the radial direction of the sun gear  158  and the rotation of which is regulated by the center bracket  157 , a plurality of planetary gears  160  meshing with the sun gear  158  and the internal gear  159 , and the like. The planetary gear  160  is rotatably supported on a carrier pin  162  fixed to a collar portion  150  provided on the motor side of the output shaft  155  via a bearing  161 .  
      A clutch  163  arranged on the output shaft  155  is constructed so as to be helical spline connected and capable of moving in the axial direction. The clutch  163  is moved in the left direction in  FIG. 6  by the roller located in a cylindrical portion  165  via a lever  164  which tilts in response to an ON operation of the electromagnetic switch  2 , and is moved in the right direction in  FIG. 6  via the lever  164  which returns to the original position in response to an OFF operation of the electromagnetic switch  2 . At this time, a collar portion  166  connectingly provided on the clutch  163  presses a ring-shaped brake member  167  shown in  FIG. 8 . The collar portion  166  is constructed so as to be also used as a stopper for stopping the movement in the right direction of the shaft of the clutch  163  and also to rapidly terminate the inertial rotation of the motor  152  after the engine has been started.  
      The brake member  167  is arranged in a bearing portion  168  provided on the center bracket  157 , and fixed to the bearing portion  168  by staking as shown in  FIG. 7 . Also, as shown in  FIG. 8 , the brake member  167  has a protrusion  169 , and the rotation of the brake member  167  is regulated by fitting this protrusion  169  in a concave portion  170  provided in the bearing portion  168 .  
      Japanese Patent Publication No. 58-23501 has disclosed a starter which incorporates a stopper mechanism in a clutch using a helical spline connection.  
       FIG. 9  is a partially sectioned front view of an essential portion of a conventional starter having a clutch incorporating a pinion movement stopping mechanism,  FIG. 10  is a perspective view of an output shaft used in  FIG. 9 , and  FIG. 11  is a partially sectional view of a clutch outer.  FIG. 12  is a sectional view taken along the line B-B of  FIG. 10 , and  FIG. 13  is a sectional view taken along the line C-C of  FIG. 10 .  
      In  FIGS. 9 through 13 , a clutch  175  of a starter  171  includes a clutch inner  182  slidably provided between an output shaft  174  integrally forming a pinion  179  at the tip end thereof and a housing case  176  via bearings  180  and  181 , and a clutch outer  184  connected to the outer periphery at one end on the anti-pinion side of the clutch inner  182  via a plurality of engagement elements  183 . On the inner peripheral surface at one end of the clutch outer  184 , as shown in  FIG. 11 , five helical splines  185  are formed at equiangular positions at intervals of 72 degrees, and the output shaft opposed to the clutch outer  184  is formed with ten (a multiple of integer) second helical splines (helical spline grooves)  186  arranged at equiangular positions. As shown in FIGS.  11  to  13 , the arrangement angle between the helical splines  185  on the inner peripheral surface of the clutch outer  184  is θ 1 , while the angle between first helical splines (helical spline grooves)  188  receiving the helical splines  185  is θ 2 . On the other hand, the angles on the side of the second helical splines  186  are θ 3  and θ 4 , and the relationship of these angles is θ 1 =θ 2 =θ 3 =θ 4 . Therefore, the number of second helical splines  186  shown in  FIG. 12  is two times that of first helical splines  188 .  
      On the other hand, in a portion  187  serving as the pinion movement stopping mechanism, the first helical splines  188  are formed at intervals equal to the intervals of the helical splines  185  on the clutch outer  184 , and portions other than the first helical splines  188  are used as contact portions of the pinion movement stopping mechanism. A groove  189  is formed between the first helical splines  188  and the second helical splines  186  to facilitate machining of the second helical splines  186  provided between the first helical splines  188 . On the other hand, an end portion of the second helical splines  186  forms a stepped portion  190 . This stepped portion  190  provides a clearance by which at least the helical splines  185  of the clutch outer  184  can be rotated without making contact. Reference numeral  172  denotes a motor,  177  denotes an electromagnetic switch, and  178  denotes a lever.  
      In the configuration of such a clutch  175 , the clutch  175  is assembled as described below. The clutch  175  is inserted from the pinion  179  side with the output shaft  174  being the center, the helical splines  185  of the clutch outer  184  are first engaged with the first helical splines  188 , and, by advancing further, are engaged with splines of the same spiral shape as the first helical splines  188 , of the second helical splines  186 . By advancing further, the helical splines  185  of the clutch outer  184  are disengaged and caused to correspond to the stepped portion  190 . At this time, by rotating the clutch outer  184  to the right or left by one spline, the helical splines  185  of the clutch outer  184  are caused to face the intermediate splines, and are engaged with them by being rotated to the left. The helical splines  185  of the clutch outer  184  are returned while being rotated until being locked by the portion  187  of the pinion movement stopping mechanism. Thereafter, a clip  192  is fitted near the pinion  179 , thereby completing the assembly.  
      By merely providing the first helical splines  188  and the second helical splines  186 , which have a different number of splines, separately on the output shaft  174 , the pinion movement stopping mechanism can be provided. The starter  171  has a construction in which the stopper in the movement direction of the output shaft  174  is formed by the pinion movement stopping mechanism incorporated in the clutch  175  and the clip  192  provided near the pinion  179 .  
      Besides, as a construction of a stopper mechanism for stopping the axial movement of pinion used in the conventional starter, in Japanese Utility Model Laid-Open No. 61-12976, a stopper member is fixed to a pinion shaft by a retaining ring, and the movement direction of the pinion shaft is regulated by the stopper member.  
      In the case where staking is used to install the brake member  167  in the conventional starter shown in FIGS.  6  to  8 , the brake member  167  is first installed to the bearing portion  168  of the output shaft  155  by using staking portions  200 . The reason for this is that if it is assumed that a stopper mechanism using two types of helical splines connections of five and ten in number is adopted as explained with reference to  FIGS. 8 through 13 , a clearance is not provided if the brake member  167  is first installed to the bearing portion  168  of the output shaft  155 , and when a need for replacing the brake member  167  arises, the brake member  167  cannot be removed or installed. In other words, in the conventional starter of a type in which the stopper mechanism using the two helical spline connections shown in FIGS.  6  to  8  is provided and the braking member  167  is installed by staking, at the time of assembling, the brake member  167  is first installed to the center bracket  157 . Therefore, a space for turning the clutch  163  in its circumferential direction cannot be secured, and helical spline connection cannot be made by shifting one spline. Also, when it is desirable to replace the brake member  167 , the center bracket  157  must also be replaced together with the brake member  167 .  
     SUMMARY OF THE INVENTION  
      It is an object of the present invention to provide a stator to rapidly terminate the inertial rotation of motor occurring when the engine is started.  
      It is anther object of the present invention to provide a stator of which the brake plate can be assembled later, so that the assembling workability is improved, and also of which the brake plate can be replaced, which improves the overhaul ability and thus offers an economical advantage.  
      It is further another object of the present invention to provide a brake plate suitable for terminating the inertial rotation of motor rapidly.  
      In a preferred embodiment disclosed by the present invention, the present invention provides a starter including an electromagnetic switch; a motor which has an armature pivotally supported on a rear bracket and a center bracket and is started by the energization of the armature caused by an ON operation of the electromagnetic switch; a pinion shift lever driven corresponding to the ON operation of the electromagnetic switch; a pinion which is engaged with a ring gear of an engine corresponding to the drive of the pinion shift lever while being rotated corresponding to the start of the motor; a clutch which is spline connected so that one of the motor output shaft side and the pinion shaft side has splines two times the number of splines of the other and a stopper mechanism utilizing the two-times splines with respect to the axial movement is provided; and a reducer provided between the motor output shaft side and the pinion shaft side, wherein locking means for detachably fixing a brake plate is provided on a wall surface on the pinion side of the center bracket pivotally supporting an output shaft of the reducer.  
      A concave portion (hereunder referred sometimes to as a substantially circular concave portion), which has a substantially circular shape as viewed from the front and has a vertical wall around it, is provided in a bearing surface on the pinion side of the center bracket, and a clip groove is provided in the inner peripheral surface of the substantially circular concave portion. Therefore, even for the clutch having the stopper mechanism utilizing different helical spline connections in which the number of splines is two times, the brake plate can be assembled later, and also can be replaced. Also, parts setting can be performed by alternative parts, so that the overhaul ability is improved.  
      Since the brake plate is circular in shape and is provided with an expanded portion, at the time of operation for terminating the inertial rotation of motor, the rotation of the brake plate is inhibited, so that motor inertial rotation terminating performance is high. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1  is a sectional view of an essential portion of one embodiment of a starter in accordance with the present invention;  
       FIG. 2  is an assembly view of a center bracket;  
       FIG. 3  is an explanatory view of a shape of a brake plate;  
       FIG. 4  is an explanatory view of a shape of a clip;  
       FIG. 5  is an explanatory view of an assembly of a brake plate in accordance with the present invention;  
       FIG. 6  is a partially sectional view of a portion near a clutch and a reducer of a conventional starter;  
       FIG. 7  is a sectional view taken along the line A-A of  FIG. 6 ;  
       FIG. 8  is an explanatory view of a shape of a brake member;  
       FIG. 9  is a partially sectioned front view of an essential portion of a conventional starter having a clutch incorporating a pinion movement stopping mechanism;  
       FIG. 10  is a perspective view of an output shaft used in  FIG. 9 ;  
       FIG. 11  is a partially sectional view of a clutch outer;  
       FIG. 12  is a sectional view taken along the line B-B of  FIG. 10 ; and  
       FIG. 13  is a sectional view taken along the line C-C of  FIG. 10 . 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       FIG. 1  is a sectional view of an essential portion of one embodiment of a starter in accordance with the present invention. Elements denoted by reference numerals  1  to  6  in  FIG. 1  may be regarded as the same as the elements used in the conventional starter. The elements are the same as those described in background of the invention before, and the operations thereof have also been described in background of the invention before, so that repeated explanation is omitted. However, some explanation is added by using  FIG. 2 , which is an assembly view of a center bracket,  FIG. 3 , which is an explanatory view of a shape of a brake plate, and  FIG. 4 , which is an explanatory view of a shape of a clip.  
      In FIGS.  1  to  3 , on the wall surface on the pinion side of the center bracket  18  on which the motor  6  is disposed, there are provided a substantially circular concave portion  111  for housing a substantially circular brake plate  19  shown in  FIG. 3  and a clip groove  112  for fixing the brake plate  19  on the inner peripheral surface of the concave portion  111 . The construction is such that the brake plate  19  is placed in the substantially circular concave portion  111 , and is fixed to the center bracket  18  by fitting a clip  113  in the clip groove  112 .  
      The brake plate  19  is formed of a resin material such as a Bakelite plate or a cloth-inserted Bakelite plate or a metallic material such as an iron plate. Preferably, a resin plate impregnated with oils should be used. In this case, even if the clutch outer  4  is pressed while being rotated, the wear of the brake plate  19  can be reduced, and frictional noise generated when the brake plate  19  comes into contact with the rotating clutch outer  4  can be reduced.  
      Also, in a part of the brake plate  19 , an opening  291  is provided so that the brake plate  19  can be inserted from the radial direction (the side) of an output shaft  115  as described later.  
      As the clip  113 , an elastic member is used. As shown in  FIG. 4 , in both end portions of the clip  113 , which is formed in a substantially circular shape having an opening portion, an attachment/detachment end portion  114  is formed to facilitate attachment and detachment of the clip  113  into and from the clip groove  112 . Although the attachment/detachment end portion  114  shown in  FIG. 4  is formed in a bent shape, it may be formed in a circular shape having a small radius.  
      An assembling method for assembling the brake plate  19  to the concave portion  111  in the center bracket  18  is explained with reference to  FIG. 1  and  FIG. 5 , which is an explanatory view of an assembly of a brake plate in accordance with the present invention. In  FIG. 5 , reference character V denotes a position in which five helical splines are provided, and W denotes a position in which ten helical splines are provided. 
          (1) The output shaft  115  is inserted from the rear side of the center bracket  18 .     (2) The collar portion  43  of the clutch outer  4  is inserted into the substantially circular concave portion  111  in the center bracket  18 , and advanced so that the end surface of the collar portion  43  abuts on a bottom surface X of the substantially circular concave portion  111 . At this time, the helical spline connection in the clutch  110  is severed, and the clutch outer  4  is in a state of being capable of rotating freely in the circumferential direction.     (3) The clutch outer  4  is shifted in phase by one helical spline.     (4) The clutch outer  4  is returned to the front side, and moved to a position at which the pinion  3  projects to a maximum. The brake plate  19  is inserted from the radial direction of the output shaft  115 , and set into the substantially circular concave portion  111  in the center bracket  18 .     (5) The clip  113  is inserted into the clip groove  112  provided on the inner peripheral surface of the circular concave portion  111  in the center bracket  18  while the clip  113  is deflected using the attachment/detachment end portions  114  of the clip  113  with a tool such as pliers, by which the brake plate  19  is fixed.        

      As shown in  FIG. 3 , in a part of the brake plate  19 , an opening  291  for allowing the shaft  115  to pass through is provided, and also an expanded portion  292  is provided in a part other than the opening  291 .  
      Referring to  FIGS. 2 and 5 , a peripheral wall  280  around the concave portion  111  in the center bracket  18  is formed in a substantially annular shape having a cut portion  280 - 1  formed by cutting a part in the circumferential direction. On both sides of the cut portion  280 - 1 , wall end portions  280 - 2  and  280 - 3 , which are end portions of the continuous wall surface, are provided.  
      The depth in the axial direction of the cut portion  280 - 1  is approximately equal to the depth of the bottom surface of the concave portion  111 .  
      A planar width l of the expanded portion  292  of the brake plate  19  is slightly narrower than a cut width L of the cut portion  280 - 1  of the peripheral wall  280  of the center bracket  18 .  
      Therefore, when the brake plate  19  is placed in the concave portion  111 , the expanded portion  292  is housed in the cut portion  280 - 1 . Therefore, even when the collar portion  43  of the rotating clutch outer  4  comes into contact with the brake plate  19 , the brake plate  19  is prevented from being rotated because the expanded portion  292  abuts on the wall end portion  280 - 2  or  280 - 3 .  
      Because the brake plate  19  does not rotate, the inertial rotation of the clutch outer  4  (i.e., the motor  6 ) can be terminated rapidly.  
      Also, the clip groove  112  in the inner peripheral surface of the concave portion  111  in the center bracket  18  is exposed in wall end portions  280 - 2  and  280 - 3  by the cut portion  280 - 1 . By causing the attachment/detachment end portions  114  to correspond to the position of the cut portion  280 - 1 , the clip  113  can prevent the brake plate  19  from being rotated under the influence of rotational force of the collar portion  43  of the clutch outer  4 , and the clip  113  can more surely be prevented from coming off from the clip groove  112 .  
      The substantially circular brake plate  19  fitted in the substantially circular concave portion  111  has a thickness T 1  larger than a distance T 2  from a position at which the front end surface of the clutch  110 , that is, the end surface of the collar portion  43  is caused to abut on the bottom surface X of the substantially circular concave portion  111  to a position at which the clutch  110  is helical spline connected.  
      The brake plate  19  has the following function in addition to its main object of reducing the number of relative rotations at the time of re-contacting, thereby reducing an impact force, and protecting strength members.  
      As shown in  FIG. 5 , T 2  represents a range in which the clutch  110  can be rotated freely in its circumferential direction, and the relationship of T 1 &gt;T 2  holds. Therefore, the brake plate  19  having a thickness of T 1  has a function of spacer for shifting the helical spline phase at the time of assembly.  
      Although one brake plate  19  having a thickness of T 1  is provided in  FIG. 5 , a plurality of, for example, two or three brake plates may be provided. When the brake plate  19  is formed by a plurality of plates, the service life of the brake plate  19  can be prolonged by changing the sequence of a worn brake plate or by replacing only a worn brake plate.