Patent Publication Number: US-8109041-B2

Title: Powered device for vehicle sliding member

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to a powered sliding device for a vehicle sliding member which is slidably moved between an open position and a closed position in a vehicle. 
     Conventionally, there has been proposed a powered sliding device for a vehicle sliding member which includes a base member and an output drum which is rotatably supported on the base member through a shaft. The output drum has a cable which is wound around an outer circumferential surface of the output drum and connected with the vehicle sliding member. The powered sliding device further includes a speed reduction mechanism connected to a motor, and a clutch mechanism for selectively switchable between an engaged state in which the clutch mechanism transmits a driving torque inputted from the motor via the speed reduction mechanism, to the output drum and a disengaged state in which the clutch mechanism prevents the driving torque from being transmitted to the output drum. 
     The clutch mechanism includes an annular field core fixed to the base member, a rotor rotatably supported on the shaft, and an armature which is supported on the shaft so as to be rotatable about an axis of the shaft and moveable in the axial direction of the shaft. The armature is constructed to be rotatable together with the output drum. When an electromagnetic winding in the field core is energized, the armature is magnetically attracted to the rotor and frictionally engaged with the rotor. The rotation of the rotor is transmitted to the output drum through the frictional engagement between the armature and the rotor, causing the vehicle sliding member to move the open position and the closed position via the cable. 
     Japanese Patent Application First Publication No. 2005-232918, corresponding to U.S. Patent Application Publication No. 2005/0183924 A1, describes such a powered sliding device as discussed above. 
     SUMMARY OF THE INVENTION 
     However, in the conventional powered sliding device as described above, the field core, the rotor, the armature and the output drum must be in turn axially assembled to the base member to which the motor and the speed reduction mechanism are previously mounted. This assembling work causes inconvenience and tends to be deteriorated in accuracy. 
     It is an object of the present invention to eliminate the above problems in the conventional art and provide a powered sliding device capable of provisionally assembling the clutch mechanism and the output drum together with each other before coupling the speed reduction mechanism to the clutch mechanism, and capable of facilitating the assembling work of the powered sliding device. 
     To achieve the above object, there is provided according to one aspect of the present invention, a powered device for a vehicle sliding member, comprising: a base member; a shaft rotatably supported on the base member; a drive source; an output drum rotatably supported on the base member through the shaft; a clutch mechanism switchable between an engaged state in which the clutch mechanism transmits a driving torque from the drive source to the output drum, and a disengaged state in which the clutch mechanism prevents the driving torque from being transmitted to the output drum; and a first stop. The clutch mechanism comprises: a rotor rotatably disposed relative to the shaft, a generally cylindrical field core disposed on the rotor, and an armature disposed on the shaft so as to be rotatable and moveable along an axis of the shaft. The armature is connected with the output drum, and has a friction surface which is opposed to the friction surface of the rotor and engageable therewith. The armature is magnetically attracted to the rotor and transmits rotation of the rotor to the output drum through the friction surfaces of the armature and rotor being engaged with each other upon energizing the field core. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a side view of a vehicle to which a powered sliding device of an embodiment of the present invention is incorporated. 
         FIG. 2  is a vertical cross-section of the powered sliding device. 
         FIG. 3  is an exploded perspective view of the powered sliding device. 
         FIG. 4  is a vertical cross-section of an essential part of the powered sliding device and shows a clutch mechanism assembled to a shaft and an output drum. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     In the following, an embodiment of the present invention will be explained in detail with reference to the accompanying drawings. For ease of understanding, various directional terms, such as, right, left, upper, lower, rightward and the like as viewed in the drawings are used in the following description. However, such terms are to be understood with respect to only the drawings on which the corresponding part or portion is shown. 
       FIG. 1  shows a side view of a vehicle of a mini-van or wagon type to which a powered sliding device of the embodiment which is incorporated. The powered sliding device is provided on left and right sides of vehicle body  2 . In  FIG. 1 , there is shown only the powered sliding device as indicated at  6 , which is provided on the left side of the vehicle body. As illustrated in  FIG. 1 , slide door  1  as a sliding member of the vehicle is supported by upper guide rail  3 , middle guide rail  4  and lower guide rail  5  so as to be moveable between a full-closed position in which slide door  1  allows an opening of vehicle body  2  for ingress/egress of a vehicle occupant to be fully covered, and a full-open position in which slide door  1  allows the opening of vehicle body  2  to be fully exposed to an outside of the vehicle, in a fore-and-aft direction of the vehicle. Slide door  1  is moveable rearward and forward from the full-closed position to the full-open position and vice versa along the side of vehicle body  2 , while slightly outward moving from an outside surface of vehicle body  2 . Slide door  1  can be thus moved by manual operation and powered sliding device  6  which is installed to a rear side portion of vehicle body  2 . 
     Referring to  FIGS. 2-4 , powered sliding device  6  is explained in detail. As illustrated in  FIGS. 2 and 3 , powered sliding device  6  includes base member  7 , motor  8  serving as a drive source, worm wheel  9  serving as a speed reduction mechanism for reducing a rotation speed of motor  8 , output drum  11  which is rotatably supported on base member  7  through shaft  10  and connected with slide door  1  through cable  13 , and clutch mechanism  12  for allowing driving connection between worm wheel  9  and output drum  11  and blocking the driving connection therebetween. 
     Base member  7  is fixed to vehicle body  2  and in the form of a metal plate. Base member  7  has one side surface, namely, a left side surface as viewed in  FIG. 2 , on which gear housing  21  is fixedly disposed. As shown in  FIG. 3 , gear housing  21  is fixed to an upper surface of base member  7  by means of screws  20 . Base member  7  has an opposite side surface, namely, a right side surface as viewed in  FIG. 2 , to which housing  23  is fixed by means of screw  22 . Housing  23  accommodates output drum  11  and clutch mechanism  12  as explained later. Motor  8  is mounted to the one side surface of base member  7  through gear housing  21 . In this embodiment, motor  8  is in the form of a reversible motor. 
     Worm wheel  9  is rotatably accommodated within gear housing  21 . Worm wheel  9  is fitted onto sleeve  211  formed inside gear housing  21 , and is rotatably supported on sleeve  211 . Worm wheel  9  meshes with worm  24  which is fixed to an output shaft of motor  8 , and is rotatable to reduce the rotation of motor  8 . Worm wheel  9  has damper plate  19  on a radial inside thereof. Damper plate  19  is constructed to be rotatable together with worm wheel  9 . Damper plate  19  acts to damp an impact which is caused when the rotation of worm wheel  9  is transmitted to rotor  16  of clutch mechanism  12 . 
     Output drum  11  is formed into a generally cylindrical shape having one closed end. Output drum  11  has an inside bottom surface, namely, a left side surface as viewed in  FIG. 2 . Output drum  11  carries cable  13  which is wound on an outer circumferential surface of output drum  11 . Cable  13  is engaged in helical groove  111  which is formed on the outer circumferential surface of output drum  11 . Helical groove  111  is best shown in  FIG. 3 . As shown in  FIG. 3 , output drum  11  has a plurality of projections  112  on an inner circumferential surface thereof. Projections  112  radially inward extend from the inner circumferential surface of output drum  11  and are circumferentially spaced from each other. Projections  112  are engaged in recesses  172  of armature  17  of clutch mechanism  12  as explained later. 
     As shown in  FIG. 1 , cable  13  wound on output drum  11  extends along guide rail  4  and is connected to slide door  1 . Cable  13  serves as a transmitting member which transmits the driving torque of motor  8  inputted to output drum  11  to slide door  1 . Cable  13  is supported and guided by guide portions, not shown, which are provided on front and rear end portions of guide rail  4 , respectively. 
     Shaft  10  extends through an opening of base member  7  in a lateral direction of the vehicle perpendicular to the fore-and-aft direction of the vehicle. Shaft  10  is supported on gear housing  21  and housing  23  so as to be rotatable about an axis thereof. Shaft  10  is integrally formed with output drum  11 . Shaft  10  includes one end portion  101  which is rotatably fitted into bearing hole  231  of housing  23 . Opposite end portion  102  of shaft  10  is rotatably supported on bearing sleeve  211  of gear housing  21  through bearing  25 . Shaft  10  further includes a clutch mounting portion which is disposed between one end portion  101  and opposite end portion  102  and supports clutch mechanism  12  thereon. The clutch mounting portion includes a major portion, increased diameter portion  104  which is larger in diameter than the major portion, and step  105  disposed between the major portion and increased diameter portion  104 . Increased diameter portion  104  axially extends from a radially inner periphery of the inside bottom surface of output drum  11 . Circumferential groove  103  is formed on an outer circumferential surface of shaft  10  between opposite end portion  102  and the clutch mounting portion. Circumferential groove  103  is engaged with stop  27  as explained later. 
     Clutch mechanism  12  is switchable between an engaged state in which clutch mechanism  12  transmits a driving torque which is inputted from motor  8  via worm wheel  9 , to output drum  11  and a disengaged state in which clutch mechanism  12  prevents the driving torque from being transmitted to output drum  11 . Clutch mechanism  12  includes field core  15 , rotor  16  and armature  17  which are disposed on the clutch mounting portion of shaft  10 . Field core  15 , rotor  16  and armature  17  are accommodated within an inside space of output drum  11 . Field core  15  includes built-in electromagnetic winding  14  and is made of a magnetic material. Field core  15  is formed into a generally cylindrical shape with central hole  151  and disposed on rotor  16  coaxially therewith. Field core  15  has one axial end surface contacted with the other side surface of base member  7  which faces toward housing  23 . Field core  15  is fixed to the other side surface of base member  7  by means of screws  26 . An opposite axial end surface of field core  15  is opposed to generally annular portion  160  of rotor  16  as explained later. 
     Rotor  16  is made of a magnetic material and rotatably and coaxially disposed on the major portion of the clutch mounting portion of shaft  10 . Rotor  16  has friction surface  164  at one axial end thereof. Specifically, rotor  16  includes generally annular portion  160  which has friction surface  164  on one side thereof, and cylindrical hub  161  which extends from an opposite side of annular portion  160  in the axial direction. Annular portion  160  has a central hole, a flange axially extending from an outer circumferential periphery, and a circumferential recess which is formed on an inner circumferential surface around the central hole. The inner circumferential recess is configured to be fitted onto increased diameter portion  104  of the clutch mounting portion of shaft  10 . Hub  161  extends from a radially inner periphery of the opposite side surface of annular portion  160  into gear housing  21  through central hole  151  of field core  15 . Hub  161  includes a large-diameter portion which is located in central hole  151  of field core  15  and a small-diameter portion which projects from central hole  151  and the opening of base member  7  and is located within gear housing  21 . The small-diameter portion has knurl  162  at which hub  161  is connected with worm wheel  9  through damper plate  19 . Hub  161  has circumferential groove  163  on an outer circumferential surface thereof between the large-diameter portion and the small-diameter portion. Circumferential groove  163  is engaged with stop  29  as explained later. 
     Armature  17  is disposed on increased diameter portion  104  of the clutch mounting portion of shaft  10  coaxially with shaft  10 . Armature  17  is rotatable about the axis of shaft  10  and moveable in the axial direction of shaft  10 . Armature  17  is formed into a disc shape with a central hole and has friction surface  171  on one side thereof which is opposed to friction surface  164  of annular portion  160  of rotor  16 . The other side of armature  17  is opposed to the inside bottom surface of output drum  11 . Displacement of armature  17  in an axial direction of shaft  10 , namely, in the rightward direction as viewed in  FIG. 2 , is limited by the inside bottom surface of output drum  11 . As shown in  FIG. 3 , armature  17  has a plurality of recesses  172  on an outer circumferential surface thereof. Recesses  172  are radially inward concaved from the outer circumferential surface of armature  17  and circumferentially spaced from each other. Recesses  172  are engaged with projections  112  of output drum  11  to thereby connect armature  17  to output drum  11 . Upon energizing field core  15 , armature  17  is magnetically attracted to annular portion  160  of rotor  16  and transmits rotation of rotor  16  to output drum  11  through friction surfaces  171  and  164  which are frictionally engaged with each other. 
     Stop  27  is disposed on shaft  10  between opposite end portion  102  and the clutch mounting portion. Stop  27  is a ring-shaped member and fitted into circumferential groove  103  which is formed on the outer circumferential surface of shaft  10 . Stop  27  is contacted with an axial end surface of hub  161  of rotor  16  and limits displacement of rotor  16  of clutch mechanism  12  relative to shaft  10  in an axial direction of shaft  10  toward opposite end portion  102 , namely, in the leftward direction as viewed in  FIG. 2 . Stop  27  cooperates with step  105  of the clutch mounting portion of shaft  10  to prevent backlash of rotor  16  relative to shaft  10  in opposite axial directions of shaft  10  and securely support hub  161  between stop  27  and step  105 . Stop  27  also prevents rotor  16  from dropping off from opposite end portion  102  of shaft  10  before worm wheel  9  is coupled to rotor  16  upon assembling powered sliding device  6  as explained later. In this embodiment, stop  27  is in the form of an E-washer. By using stop  27 , the assembling operation of powered sliding device  6  can be efficiently performed. 
     Stop  29  is disposed on hub  161  of rotor  16  and located between armature  17  and stop  27  in the axial direction of rotor  16 . Stop  29  is a ring-shaped member and fitted into circumferential groove  163  which is formed on the outer circumferential surface of hub  161  between the large-diameter portion and the small-diameter portion. Stop  29  is contacted with a radially inner periphery of the one axial end surface of field core  15  and limits displacement of field core  15  relative to rotor  16  in an axial direction of rotor  16  toward damper plate  19 , namely, in the leftward direction when viewed in  FIG. 2 . Stop  29  cooperates with annular portion  160  of rotor  16  to prevent backlash of field core  15  relative to hub  161  in opposite axial direction of rotor  16  and securely support field core  15  between stop  29  and annular portion  160 . Stop  29  also prevents field core  15  from dropping off from hub  161  of rotor  16  before worm wheel  9  is coupled to rotor  16  upon assembling powered sliding device  6 . By using stop  29 , the assembling operation of powered sliding device  6  can be facilitated and efficiently performed. 
     Biasing member  28  is disposed between annular portion  160  of rotor  16  and armature  17 . Biasing member  28  is fitted onto increased diameter portion  104  of the clutch mounting portion of shaft  10  and interposed between a radially inner periphery of friction surface  164  of rotor  16  and a radially inner periphery of friction surface  171  of armature  17  which is opposed to the radially inner periphery of friction surface  164  in the axial direction of shaft  10 . Biasing member  28  is constructed to be elastically deformable to bias rotor  16  and armature  17  in such a direction as to move friction surfaces  164  and  171  away from each other. That is, biasing member  28  biases rotor  16  and armature  17  in opposite axial directions of shaft  10 . In this embodiment, biasing member  28  is in the form of a wave washer. 
     When electromagnetic winding  14  of field core  15  is energized and clutch mechanism  12  is placed in the engaged state, armature  17  is magnetically attracted to rotor  16  so that friction surfaces  171  and  164  are frictionally engaged with each other to thereby establish driving connection between rotor  16  and armature  17 . In this state, the rotation of motor  8  is transmitted to output drum  11  via worm  24 , worm wheel  9 , damper plate  19 , rotor  16  and armature  17 . Then, cable  13  is taken up over the outer circumferential surface of output drum  11  to thereby move slide door  1  in the open or closed direction. On the other hand, when electromagnetic winding  14  of field core  15  is de-energized and clutch mechanism  12  is placed in the disengaged state, armature  17  is prevented from being magnetically attracted to rotor  16  so that friction surfaces  171  and  164  are free from frictional engagement with each other to thereby inhibit driving connection between rotor  16  and armature  17 . In this state, the rotation of motor  8  is not transmitted to output drum  11  and slide door  1  can be manually operated in the open or closed direction without inversely rotating motor  8  and worm wheel  9 . 
     Powered sliding device  6  of this embodiment can perform the following effects. With the provision of stop  27 , displacement of rotor  16  of clutch mechanism  12  relative to shaft  10  in the axial direction of shaft  10  toward opposite end portion  102  can be limited. Further, with the cooperation of stop  27  and step  105  of the clutch mounting portion of shaft  10 , backlash of rotor  16  relative to shaft  10  in the opposite axial directions of shaft  10  can be effectively suppressed so that hub  161  is securely supported between stop  27  and step  105 . 
     With the provision of stop  29 , displacement of field core  15  relative to rotor  16  in the axial direction of rotor  16  toward damper plate  19  can be limited. Further, with the cooperation of stop  29  and annular portion  160  of rotor  16 , backlash of field core  15  relative to rotor  16  in the opposite axial directions of rotor  16  can be effectively suppressed so that field core  15  is securely supported between stop  29  and annular portion  160 . 
     With the arrangement of biasing member  28  between annular portion  160  of rotor  16  and armature  17 , rotor  16  and armature  17  can be free from axial backlash on shaft  10 , respectively. 
     With the construction of shaft  10  integrally formed with output drum  11 , the number of parts of powered sliding device  6  can be reduced to thereby simplify the construction of powered sliding device  6 . 
     With the connection of hub  161  of rotor  16  with worm wheel  9 , rotor  16  can be surely coupled to worm wheel  9  as the speed reduction mechanism and the construction of powered sliding device  6  can be simplified. 
     A method of assembling powered sliding device  6  of this embodiment will be explained hereinafter. First, armature  17  and rotor  16  of clutch mechanism  12  are mounted onto the clutch mounting portion of shaft  10  integrally formed with output drum  11 , in such a manner that friction surface  171  of armature  17  and friction surface  164  of rotor  16  are opposed to each other. Upon this mounting operation, armature  17  is placed in a circumferential position on increased diameter portion  104  of the clutch mounting portion such that recesses  172  of armature  17  are engaged with projections  112  of output drum  11 . Subsequently, stop  27  is fitted into circumferential groove  103  of shaft  10  to thereby prevent rotor  16  from dropping off from shaft  10 . Thus, rotor  16  and armature  17  are provisionally assembled to shaft  10  without dropping off from shaft  10 . 
     Next, field core  15  with electromagnetic winding  14  is mounted onto hub  161  of rotor  16 . Stop  29  is then fitted into circumferential groove  163  of hub  161  to thereby prevent field core  15  from dropping off from hub  161 . Thus, field core  15  is provisionally assembled to rotor  16  without dropping off from rotor  16 . Clutch mechanism  12  is thus assembled to shaft  10  and output drum  11 .  FIG. 4  shows the assembled state of clutch mechanism  12 . 
     Subsequently, field core  15  of clutch mechanism  12  is fixed to base member  7  by means of screws  26 . Clutch mechanism  12  assembled to shaft  10  and output drum  11  is thus assembled to base member  7 . Next, worm wheel  9  is coupled to hub  161  of rotor  16  by engaging damper plate  19  with knurl  162  of the small-diameter portion of hub  161 . Motor  8  which is previously accommodated in gear housing  21 , is coupled to worm wheel  9  through worm  24 . Thus, motor  8  and gear housing  21  are mounted to base member  7  through worm wheel  9  and clutch mechanism  12 . 
     The method of assembling powered sliding device  6  of this embodiment can perform the following effects. By using stop  27  and stop  29  fitted into corresponding circumferential grooves  103  and  163 , rotor  16  and armature  17  can be provisionally assembled to shaft  10  without dropping off from shaft  10  and field core  15  can be provisionally assembled to rotor  16  without dropping off from rotor  16 , before coupling worm wheel  9  to rotor  16 . Therefore, clutch mechanism  12  can be efficiently assembled to shaft  10  integrally formed with output drum  11 . This serves for facilitating the assembling operation of powered sliding device  6 . 
     In powered sliding device  6  of this embodiment, shaft  10  is integrally formed with output drum  11 . However, shaft  10  and output drum  11  can be formed as separate members independent of each other. Further, damper plate  19  can be omitted and rotor  16  can be directly connected with worm wheel  9 . Further, biasing member  28  can be disposed between output drum  11  and armature  17  so as to bias armature  17  in such a direction as to always contact friction surface  171  of armature  17  with friction surface  164  of rotor  16 . With this arrangement of biasing member  28 , rotor  16  and armature  17  can be free from axial backlash relative to each other on shaft  10 . Furthermore, although powered sliding device  6  is applied to slide door  1  in the above-described embodiment, powered sliding device  6  may be applied to various kinds of vehicle sliding members such as a back door, a sunroof, a window and the like. 
     This application is based on a prior Japanese Patent Application No. 2006-225042 filed on Aug. 22, 2006. The entire contents of the Japanese Patent Application No. 2006-225042 is hereby incorporated by reference. 
     Although the invention has been described above by reference to a certain embodiment of the invention, the invention is not limited to the embodiment described above. Modifications and variations of the embodiment described above will occur to those skilled in the art in light of the above teachings. The scope of the invention is defined with reference to the following claims.