Patent Publication Number: US-2004051318-A1

Title: Starter

Description:
BACKGROUND OF THE INVENTION  
       [0001] This invention relates to a starter having a rotation restricting mechanism for restricting the rotation of a pinion gear and pushing the pinion gear in the axial direction for engagement with a ring gear of an engine under the condition that the rotation of the pinion gear is restricted.  
       [0002] Increase of carbon dioxides in the air induces serious global warming problems and other related pollutions or destructions of global environments. To eliminate such problems, the automotive vehicles are strongly required to improve the fuel economy. To this end, a starter serving as one of accessories of the engine must reduce its weight.  
       [0003] For example, the U.S. Pat. No. 5,777,393 discloses a conventional starter which includes a pinion engaged with an output shaft via a helical spline coupling and a pinion rotation restricting member for restricting the rotation of the pinion. According to this conventional starter, the pinion shifts on the output shaft in the direction departing from a motor and meshes with a ring gear of the engine while rotation of the pinion is restricted by the pinion rotation restricting member.  
       [0004] According to the above conventional starter, no mechanism is required for directly utilizing a magnetic force generated from an electromagnetic switch to push the pinion toward the ring gear of the engine. Accordingly, it becomes possible to reduce the size of a solenoid to be incorporated in the electromagnetic switch. The magnetic force of the electromagnetic switch utilized by the above conventional starter is for actuating the pinion rotation restricting member. The force required for actuating the pinion rotation restricting member is fairly small compared with the force for pushing the pinion. This is the reason why the electromagnetic switch can be downsized. Accordingly, the starter can be downsized in structure and reduced in weight.  
       [0005] However, the pinion rotation restricting member used in the above conventional starter is constituted by a rigid spring rod member configured into a circular shape having a diameter larger than that of an outer diameter of the pinion. Thus, the pinion rotation restricting member has a relatively large mass and requires a special spring for returning the pinion rotation restricting member to its initial position after the engine has started. In other words, the pinion rotation restricting member having a large mass cannot be returned to its initial position by solely using a relatively weak spring incorporated in the electromagnetic switch (which is used for returning a plunger).  
       [0006] Accordingly, it is necessary to actuate the pinion rotation restricting member against a reaction force of the return spring in the engine startup operation. The magnetic force of the electromagnetic switch must be increased. As a result, the size of the solenoid becomes large. The electromagnetic switch cannot be downsized satisfactorily.  
       [0007] Furthermore, the above conventional starter has a structure for shifting the pinion rotation restricting member in a direction substantially normal to the rotational axis of the pinion rotation restricting member. Thus, an appropriate guide member is provided to guide the shift movement of the pinion rotation restricting member. The total number of constituent parts of the starter increases.  
       SUMMARY OF THE INVENTION  
       [0008] In view of the above-described problems, the present invention has an object to provide a starter having a rotation restricting mechanism which is capable of reducing the total number of constituent parts and also capable of sufficiently reducing the size of an electromagnetic switch.  
       [0009] In order to accomplish the above and other related objects, the present invention provides a starter including a motor for generating a rotational force, a rotary output shaft being driven by the motor, an electromagnetic switch for ON/OFF controlling electric power supply to the motor, and a pinion shift member engaged with the rotary output shaft via a helical spline coupling so as to shift in an axial direction on the rotary output shaft. The pinion shift member has a pinion gear selectively engaging with a ring gear of an engine when the pinion shift member shifts in a direction departing from the motor. A rotation restricting member, having an engaging portion extending in a direction crossing with a rotational direction of the pinion shift member, restricts the rotation of the rotation restricting member by engaging with an engaging portion of the pinion shift member. An actuating means is provided for actuating the rotation restricting member by utilizing a magnetic force generated from the electromagnetic switch. According to the present invention, the actuating means has a rod portion rotating in response to the magnetic force of the electromagnetic switch and an actuating arm formed at a distal end of the rod portion so as to swing about an axis of the rod portion when the rod portion rotates. The rotation restricting member is assembled with the actuating arm and is movable together with the actuating arm.  
       [0010] According to the arrangement of the present invention, the rotation restricting member is assembled with the actuating arm so as to be movable together. The weight of the rotation restricting member is small. It is possible to return the rotation restricting member to the original position by using only the resilient force of the spring incorporated in the electromagnetic switch for returning the plunger to its initial position. No special spring is required for returning the rotation restricting member. Furthermore, no guide member is required for shifting the rotation restricting member. The costs for the constituent parts of the starter can be reduced. No special space for disposing the guide member is required. The starter can be sufficiently downsized.  
       [0011] Preferably, the rotation restricting member includes first and second bent portions which are substantially parallel to each other and have coupling holes through which the rotation restricting member is assembled with the actuating arm of the actuating means, and the engaging portion of the rotation restricting member is provided on the first bent portion. According to this arrangement, two bent portions can surely prevent the rotation restricting member from inclining when it restricts the rotation of the pinion shift member.  
       [0012] Preferably, the rotation restricting member is shiftable in a longitudinal direction of the actuating arm and is not rotatable about an axis of the actuating arm. According to this arrangement, when the pinion shift member is shifted in the direction departing from the motor to bring the pinion gear into engagement with the ring gear (especially, when the tooth traces of the pinion gear and the ring gear disagree), the rotation restricting member shifting in the longitudinal direction of the actuating arm allows the pinion shift member to rotate slightly until their tooth traces agree. Furthermore, as no relative rotation is caused between the rotation restricting member and the actuating arm, the rotation restricting member can surely restrict the rotation of the pinion shift member while giving a predetermined rotation restricting load.  
       [0013] Preferably, a stopper is provided on the actuating arm so as to be positioned between the first bent portion and the second bent portion, and a return spring is provided for resiliently urging the rotation restricting member. With this arrangement, the rotation restricting member itself needs not have a return spring function. The rotation restricting member can be configured into an optimum shape for restricting the rotation of the pinion shift member.  
       [0014] Preferably, the return spring is disposed between the stopper and the second bent portion to give a predetermined initial resilient force to the rotation restricting member when the first bent portion is brought into contact with the stopper. According to this arrangement, the return spring is disposed between the first bent portion and the second bent portion. It is not necessary to elongate the length of the actuating arm.  
       [0015] Furthermore, as the return spring gives the predetermined initial resilient force to the rotation restricting member, contact between the first bent portion and the stopper can be maintained with no play of the rotation restricting member in the longitudinal direction of the actuating arm. Thus, the rotation of the pinion shift member is surely restricted.  
       [0016] Preferably, the rotation restricting member is subjected, in its manufacturing process, to a heat treatment to assure a predetermined hardness for the engaging portion.  
       [0017] Preferably, the engaging portion of the pinion shift member has a plurality of recessed portions provided along its radially outer periphery. The engaging portion of the rotation restricting member enters into one of the recessed portions to restrict the rotation of the pinion shift member. And, the engaging portion of the rotation restricting member has at least one chamfered face for smoothly guiding the engagement between the rotation restricting member and the pinion shift member.  
       [0018] Preferably, the actuating means has a connecting means intervening between the rod portion and the actuating arm to detachably connect the rod portion and the actuating arm. 
     
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
     [0019] The above and other objects, features and advantages of the present invention will become more apparent from the following detailed description which is to be read in conjunction with the accompanying drawings, in which:  
     [0020]FIG. 1 is a cross-sectional view showing the arrangement of a starter in accordance with a first embodiment of the present invention;  
     [0021]FIGS. 2A to  2 C are views explaining operation of a rotation restricting member of the starter in accordance with the first embodiment of the present invention;  
     [0022]FIG. 3 is a perspective view showing the rotation restricting member and a crank bar of the starter in accordance with the first embodiment of the present invention;  
     [0023]FIG. 4 is an enlarged view showing a front end of an engaging portion of the rotation restricting member in accordance with the first embodiment of the present invention;  
     [0024]FIG. 5 is a diagram showing an electric circuit for the starter in accordance with the first embodiment of the present invention;  
     [0025]FIG. 6 is a front view of a pinion shift member and a rotation restricting member in accordance with a second embodiment of the present invention; and  
     [0026]FIG. 7 is a perspective view showing the rotation restricting member and a crank bar of the starter in accordance with the second embodiment of the present invention. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
     [0027] Preferred embodiments of the present invention will be explained hereinafter with reference to attached drawings.  
     First Embodiment  
     [0028] As shown in FIG. 1, a starter  1  of this embodiment of the present invention includes a motor  2  which generates a rotational force in response to supplied electric power. An electromagnetic switch  3  is provided for ON/OFF controlling electric power supplied to the motor  2 . A rotary output shaft  4  is driven by the motor  2  and rotates about its axis. A sleeve-like pinion shift member  5  is slidably coupled around the cylindrical body of the output shaft  4 . A rotation restricting member  6  is provided to restrict rotation of the pinion shift member  5  during an engine startup operation. A crank bar  7 , serving as an actuating member, is provided to actuate the rotation restricting member  6  in response to a magnetic attraction force generated from the electromagnetic switch  3 .  
     [0029] The motor  2  is a well-known direct-current motor including a yoke  8 , a field magnet  9  (e.g., permanent magnet), an armature  10 , and a brush  11  (refer to FIG. 5). When the motor contact (described below) incorporated in the electromagnetic switch  3  is closed, battery current flows via the brush  11  into the armature  10 . The armature  10  causes a rotational force.  
     [0030] The electromagnetic switch  3  is disposed at a rear end of a starter body and covered by an end frame  12 . The electromagnetic switch  3  includes a solenoid  14 , a plunger  15 , a spring  16 , a pair of first and second movable contacts  17  and  18 , and a pair of first and second stationary contacts  19  and  20 . The solenoid  14  generates a magnetic force in response to ON operation of an ignition (IG) switch  13  (refer to FIG. 5). The plunger  15 , disposed inside the solenoid  14 , slides in the axial direction of the solenoid  14  in response to the magnetic force generated by the solenoid  14  when electric power is supplied to the solenoid  14 . The spring  16 , resiliently urging the plunger  15 , returns the plunger  15  to its initial position when electric power supply to the solenoid  14  is stopped. The movable contacts  17  and  18  and the stationary contacts  19  and  20  cooperatively constitute motor contacts.  
     [0031] The first movable contact  17  is connected via a link member (not shown) to the plunger  15 . The second movable contact  18  is mechanically and electrically connected to the first movable contact  17 . Thus, each of the first and second movable contacts  17  and  18  moves together with the plunger  15 . The second movable contact  18  is connected to the brush  11  serving as a positive-side brush. The first stationary contact  19  is disposed in a confronting relationship with the first movable contact  17 . The second stationary contact  20  is disposed in a confronting relationship with the second movable contact  18 . The first stationary contact  19  is integrally provided with a terminal bolt  21  fixed to the end frame  12 . The second stationary contact  20  is mechanically and electrically connected to the first stationary contact  19  and fixed to the end frame  12 .  
     [0032] The second stationary contact  20  is made of a carbon material having a higher electric resistance compared with the first stationary contact  19 .  
     [0033] In the condition that the plunger  15  is stopped at its initial position (shown in FIG. 1), the relationship A&gt;B is established when ‘A’ represents the distance between the first stationary contact  19  and the first movable contact  17 , and ‘B’ represents the distance between the second stationary contact  20  and the second movable contact  18  (refer to FIG. 5).  
     [0034] Satisfying the above relationship is effective to suppress the rotational speed of the armature  10  to a lower level immediately after the motor  2  is started. More specifically, when electric power is supplied to the solenoid  14 , the plunger  15  is magnetically attracted by the solenoid  14  and shifts upward in the illustration shown in FIG. 1. In this shift movement, the second movable contact  18  is brought into contact with the second stationary contact  20  earlier than the first movable contact  17  contacting with the first stationary contact  19 . In this moment, current flows via the second stationary contact  20  having a higher electric resistance from a battery  42  to the armature  10 . Due to a significant voltage drop at the second stationary contact  20 , the voltage applied to the armature  10  is relatively small. Thus, the armature  10  rotates at relatively lower speeds. Thereafter, the first movable contact  17  is brought into contact with the first stationary contact  19 . At this moment, all of the battery voltage (i.e., a rated voltage of the battery  42 ) is applied via the first stationary contact  19  to the armature  10 . Thus, the armature  10  rotates at higher speeds.  
     [0035] The output shaft  4  is rotatably supported by a bearing  23  fixed to a front housing  22  and a bearing  25  fixed to a center plate  24 . The output shaft  4  is connected to an armature shaft  10   a  (i.e., an output shaft) of the motor  2  via a speed-reduction device and a one-way clutch.  
     [0036] The speed-reduction device includes a sun gear  26  integrally formed at a distal end of the armature shaft  10   a , an internal gear  27  fixed to the center plate  24 , and a plurality of planetary gears  28  interposing between the sun gear  26  and the internal gear  27  so as to mesh with each of the sun gear  26  and the internal gear  27 . When the sun gear  26  rotates, the planetary gears  28  cause an orbital motion about the sun gear  26 . Thus, the sun gear  26 , the internal gear  27 , and the planetary gears  28  cooperatively constitute a planetary gear type speed-reduction device.  
     [0037] The one-way clutch includes an outer member  29  to which the orbital motion of the planetary gears  28  is transmitted and an inner member  30  disposed at a radially inner side of the outer member  29 . Furthermore, the one-way clutch includes rollers  31  disposed in wedge-shaped spaces formed between the outer member  29  and the inner member  30 .  
     [0038] A predetermined number of support pins  33  are press-fitted into the outer member  29 . Each planetary gear  28  is rotatably supported via a bearing  32  by a corresponding support pin  33 . When the planetary gears  28  cause the orbital motion about the sun gear  26 , the orbital motion of planetary gears  28  is transmitted via the support pins  33  to the outer member  29 . Thus, the outer member  29  rotates at a reduced speed in response to the rotation of the armature shaft  10   a.    
     [0039] The inner member  30 , provided at a rear end of the output shaft  4 , rotates integrally with the output shaft  4 . The rollers  31 , when the outer member  29  rotates in response to the orbital motion of the planetary gears  28 , are locked between the outer member  29  and the inner member  30 . The rotation of the outer member  29  is transmitted via the rollers  31  to the inner member  30 . On the other hand, when the rotational speed of inner member  30  exceeds the rotational speed of outer member  29  after the engine is started up, the rollers  31  are unlocked from the outer member  29  and the inner member  30 . The outer member  29  and the inner member  30  cause slip, and no driving power is transmitted from the outer member  29  to the inner member  30 .  
     [0040] The pinion shift member  5  includes a pinion gear  34  meshing with a ring gear (not shown) of the engine during a startup operation of the engine and a flange portion  35  (serving as an engaging portion) provided at a rear side closer to the speed-reduction device. An internal helical spline  5   a  is formed on an inner cylindrical surface of the pinion shift member  5 . The internal helical spline  5   a  meshes with an external helical spline  4   a  formed on an outer cylindrical surface of the output shaft  4 . Thus, the pinion shift member  5  slides in the axial direction of the output shaft  4  and is coupled around the output shaft  4  via the helical spline engagement so as not to cause a relative rotation. A spring  36  resiliently urges the pinion shift member  5  toward the speed-reduction device. As shown in FIG. 2, a large number of recessed portions  35   a  are formed along a radially outer periphery of the flange portion  35 .  
     [0041] The pinion shift member  5  holds a detent member  37  which cooperates with the rotation restricting member  6  for preventing the pinion shift member  5  from returning toward the speed-reduction device after the pinion gear  34  has meshed with the ring gear. The detent member  37  has one end swinging about a hook  38  fixed to the center plate  24 . An intermediate portion of the detent member  37  is swingably held by a holder (not shown) provided at a rear end surface of the pinion shift member  5 .  
     [0042] The crank bar  7 , being constituted for example by a single metal rod, has a connecting portion  7   a  engaged with a hook portion  39  provided on the plunger  15  of the electromagnetic switch  3 , an actuating arm  7   b  assembled with the rotation restricting member  6 , and a rod portion  7   c  extending from the connecting portion  7   a  to the actuating arm  7   b . The connecting portion  7   a , being formed by bending one end of the metal bar perpendicularly, is rotatably inserted into a through-hole of the hook portion  39 . The rod portion  7   c  passes a clearance of the field magnet  9  (for example, a space between two adjacent magnets disposed in the circumferential direction) in parallel with an axial direction of the motor  2 . A bearing (not shown) supports the rod portion  7   c  so as to rotate about its axis.  
     [0043] The actuating arm  7   b  is formed by bending the other end of the metal bar perpendicular and is positioned just beyond the center plate  24 . As shown in FIG. 2B, the actuating arm  7   b  is disposed adjacently to the radially outer periphery of the flange portion  35  provided on the pinion shift member  5 . The actuating arm  7   b  extends in a direction crossing with the axial direction of the pinion shift member  5 . The crank bar  7  rotates about its axis when the shift movement of the plunger  15  (i.e., up-and-down shift movement in FIG. 1) is transmitted to the rod portion  7   c  via the connecting portion  7   a . As a result, the actuating arm  7   b  swings about an axis of the rod portion  7   c  as indicated by an arrow shown in FIG. 2A,  
     [0044] The rotation restricting member  6 , as shown in FIG. 3, is formed by bending a plate member into a U-shaped configuration. The actuating arm  7   b  is assembled with the rotation restricting member  6 . More specifically, the rotation restricting member  6  includes a first bent portion  6   a  and a second bent portion  6   c  being substantially parallel to each other and having coupling holes through which the rotation restricting member  6  is swingably supported by the actuating arm  7   b  of the crank bar  7 . The cross-sectional shape of the actuating arm  7   b  and the cross-sectional shape of the coupling holes of first and second bent portions  6   a  and  6   c  are D shape or any other modified shape, so that no relative rotation is caused between the rotation restricting member  6  and the actuating arm  7   b.    
     [0045] An engaging portion  6   c  is integrally formed with the first bent portion  6   a  of the rotation restricting member  6 . When the actuating arm  7   b  shifts toward the pinion shift member  5  (i.e., in the direction indicated by the arrow ‘a’ in FIG. 2A), the engaging portion  6   c  engages with one of the recessed portions  35   a  formed on the flange portion  35  so as to prevent the pinion shift member  5  from rotating.  
     [0046] The engaging portion  6   c , as shown in FIG. 1, is disposed along the axial direction of the pinion shift member  5  so as to have a predetermined longitudinal length. As shown in FIG. 4, chamfered faces  6   d  are formed at one end of the engaging portion  6   c  to smoothly guide the engagement between the rotation restricting member  6  and the flange portion  35 .  
     [0047] In its manufacturing processes, the rotation restricting member  6  having the engaging portion  6   c  is subjected to a heat treatment (e.g., induction hardening) to assure a predetermined hardness for the engaging portion  6   c.    
     [0048] A stopper  40  is provided on the actuating arm  7   b  so as to be positioned between the first bent portion  6   a  and the second bent portion  6   b . The first bent portion  6   a  is brought into contact with the stopper  40  at an in initial position. From this initial condition, the first bent portion  6   a  is freely shiftable toward the distal end of the actuating arm  7   b . On the other hand, the first bent portion  6   a  is stopped by the stopper  40  when it moves toward the rod portion  7   c . A return spring  41  is interposed between the stopper  40  and the second bent portion  6   b . The return spring  41  resiliently urges the second bent portion  6   b  of rotation restricting member  6 . In other words, the return spring is disposed between the stopper  40  and the second bent portion  6   b  to give a predetermined initial resilient force to the rotation restricting member  6  when the first bent portion  6   a  is brought into contact with the stopper  40 .  
     [0049] The above-described starter operates in the following manner.  
     [0050] When the IG switch  13  is closed (i.e., turned on), electric power is supplied from the battery  42  to the solenoid  14  of electromagnetic switch  3 . The solenoid  14  generates a magnetic field, and accordingly the plunger  15  is drawn upward in FIG. 1. The shift movement of the plunger  15  is transmitted to the rotation restricting member  6  via the crank bar  7 . The rotation restricting member  6  shifts upward in FIG. 1. As shown in FIG. 2B, the engaging portion  6   c  of the rotation restricting member  6  engages with the recessed portion  35  of flange portion  35 . Thus, the pinion shift member  5  is locked (i.e., restricted so as not to be rotated) by the rotation restricting member  6 .  
     [0051] On the other hand, in accordance with a shift movement of the plunger  15 , the second movable contact  18  in the electromagnetic switch  3  is brought into contact with the second stationary contact  20  earlier than the contact timing of the first movable contact  17 . A relatively small current flows from the battery  42  to the armature  10 . The armature  10  rotates at lower speeds. The rotational speed of armature  10  is reduced by the speed-reduction device and is transmitted via the one-way clutch to the output shaft  4 . While the output shaft  4  is rotating, the pinion shift member  5  is locked by the rotation restricting member  6 . Thus, the rotation force of output shaft  4  is transmitted as a thrust force via the helical spline coupling to the pinion shift member  5 .  
     [0052] Accordingly, the pinion shift member  5  shifts forward on the output shaft  4  until an end surface of the pinion gear  34  is brought into contact with the ring gear of the engine. The pinion gear  34  will not be able to engage with the ring gear if their tooth traces disagree. In this case, the pinion shift member  5  cannot advance forward. Under this stalling condition, the rotational force of output shaft  4  is not converted into a thrust force of the pinion shift member  5 . Accordingly, a rotational force is given to the pinion shift member  5 .  
     [0053] At this moment, rotation of the pinion shift member  5  is restricted by the rotation restricting member  6 . However, the rotational force given to the pinion shift member  5  is larger than a resilient force of the return spring  41 . The pinion shift member  5 , overcoming the resilient force of the return spring  41 , starts rotating under the condition that the engaging portion  6   c  of rotation restricting member  6  is engaged with the recessed portion  35   a  of the flange portion  35 . In response to the rotation of pinion shift member  5 , the rotation restricting member  6  shifts toward the distal end of the actuating arm  7   b  while it deforms the return spring  41  as shown in FIG. 2C.  
     [0054] While the pinion shift member  5  rotates by an amount corresponding to one pitch of the pinion gear  34 , the pinion gear  34  can mesh with the ring gear when their tooth traces agree. Thus, the pinion shift member  5  advances again on the output shaft  4  under the given thrust force. The pinion gear  34  can mesh with the ring gear soon.  
     [0055] Once the pinion gear  34  completely meshes with the ring gear of the engine, the engaging portion  6   c  of rotation restricting member  6  is disengaged from the recessed portion  35   a  of the flange portion  3 . The rotation restricting member  6  is pushed back by the resilient force of the return spring  41 , and returns to its initial position along the actuating arm  7   b . Furthermore, the rotation restricting member  6  enters behind a rear end of the detent member  37  which is disposed at the rear side of the pinion shift member  5 . Thus, the rearward movement of the pinion shift member  5  along the output shaft  4  is prevented by the detent member  37 .  
     [0056] The detent member  37  swings about its one end being supported by the hook  38  in accordance with the forward movement of the pinion shift member  5 . The lower end of the detent member  37  is disposed closely to the rear end surface of the pinion shift member  5 .  
     [0057] When the IG switch  13  is opened (i.e., turned off) after succeeding the engine startup operation, no electric power is supplied to the solenoid  14  of electromagnetic switch  3 . The solenoid  14  generates no magnetic force. The plunger  15  is resiliently pushed down by the spring  16  and returns to its initial position. In accordance with the shift movement of the plunger  15 , the rod portion  7   c  of crank bar  7  rotates in the opposite direction and accordingly the actuating arm  7   b  rotates about the axis of rod portion  7   c  and returns to its initial position as indicated by an arrow b shown in FIG. 2A.  
     [0058] As a result of the above return movement of the crank bar  7 , the engaging portion  6   c  of the rotation restricting member  6  is released from the detent member  37 . The pinion shift member  5  is unlocked from the detent member  37  and shifts rearward on the output shaft  4  under the resilient force acting from the spring  36  and a pushing force acting from the ring gear. Thus, the pinion shift member  5  returns to a stationary position shown in FIG. 1.  
     [0059] According to the starter  1  of this embodiment, the rotation restricting member  6  restricting the rotation of the pinion shift member  5  is assembled with the actuating arm  7   b  of crank bar  7 . The rotation restricting member  6  is movable together with the actuating arm  7   b . The rotation restricting member  6  is compact is size and light in weight. The resilient force of the spring  16  incorporated in the electromagnetic switch  3  can be utilized for returning the rotation restricting member  6  to the original position. Namely, the rotation restricting member  6  has a relatively small mass, and the operation of the crank bar  7  is represented by a rotational motion about the rod portion  7   c . The operation force required to operate the crank bar  7  is small.  
     [0060] Thus, it is possible to return the rotation restricting member  6  to the original position by using only a reaction force of the spring  16  incorporated in the electromagnetic switch  3 . It is not necessary to use a dedicated or special return spring. It is thus unnecessary to move the rotation restricting member  6  against the reaction force of the dedicated spring in restricting the rotation of the pinion shift member  5  during the engine startup operation. It becomes possible to reduce a magnetic attraction force of the electromagnetic switch  3 . As a result, the solenoid  14  can be downsized. The electromagnetic switch  3  can be downsized, too.  
     [0061] Furthermore, no guide member is required for guiding the shift movement of the rotation restricting member  6  because the rotation restricting member  6  is movable together with the actuating arm  7   b . The total costs of constituent parts of the starter  1  can be decreased. No space is required for installing the guide member. The starter  1  can be downsized.  
     [0062] Furthermore, the rotation restricting member  6  has the first bent portion  6   a  and the second bent portion  6   b  via which the actuating arm  7   b  is supported. In restricting the rotation of the pinion shift member  5 , two bent portions  6   a  and  6   b  can surely prevent the rotation restricting member  6  from inclining. Thus, the rotation of the pinion shift member  5  can be surely prevented.  
     Second Embodiment  
     [0063]FIG. 7 is a perspective view showing a rotation restricting member  6  and a crank bar  7  in accordance with a second embodiment of the present invention. According to this embodiment, a rod portion  7   c  of the crank bar  7  is separated from an actuating arm  7   b.    
     [0064] The actuating arm  7   b  has a female joint  7   d  formed at its end, while the rod portion  7   c  has a male joint  7   e  formed at its end. The female joint  7   d  and the male joint  7   e  are detachably engaged with each other so as to constitute a connecting means.  
     [0065] The female joint  7   d  has a cylindrical sleeve-like shape having a plurality of axially-extending engaging grooves  7   f  formed on an inner cylindrical surface. The male joint  7   e  is composed of a plurality of axially-extending engaging protrusions  7   g  formed on an outer cylindrical surface of the rod portion  7   c . When the male joint  7   e  is inserted into the female joint  7   d , the engaging protrusions  7   g  mate with the engaging grooves  7   f  so as to cause no relative rotation therebetween (refer to FIG. 6).  
     [0066] According to this embodiment, the male joint  7   e  is formed on the straight end portion of the rod portion  7   c . In the assembling processes of the starter  1 , it is unnecessary to bend the rod portion  7   c . It is also unnecessary to use a predetermined fixing member after the connecting portion  7   a  of crank bar  7  is inserted into the hook portion  39  in the final step of installing the solenoid  14  of electromagnetic switch  3 . Thus, it becomes possible to employ a simple assembling method according to which the constituent parts are successively and easily assembled on the front housing  22 .