Webbing Retractor

Abstract

A webbing retractor 10 has a structure in which a housing 48, to which a motor 44 is attached, faces in an axial direction of a worm gear 34, and is assembled and fixed to an end face of a case 30 which is orthogonal to a direction of thickness of the case 30, in which a clutch 26 which is attached in a joined state to a side face of one leg plate 16 is accommodated, and at an opposite side from a back plate 14. Moreover, this is a structure in which a rotation shaft of the motor 44 is between the leg plate 16 and a leg plate 18 in a state of being orthogonal to a winding shaft 20, and the motor 44 is disposed directly below the winding shaft 20.

1 . A webbing retractor comprising: 
 a frame formed of a pair of leg plates facing one another and a back plate, the frame being a single body at which the pair of leg plates are continuous with the back plate;    a winding shaft which is rotatably supported between the pair of leg plates with an axial direction thereof being along a direction of facing of the pair of leg plates, at which a base end portion of a webbing belt for restraining a vehicle occupant is engaged, and which winds up the webbing belt by rotation in one direction about its axis;    a gear housing;    a motor attached at the gear housing, which is disposed between the pair of leg plates in a state in which a rotation shaft thereof is orthogonal to the winding shaft;    a motor gear section accommodated in the gear housing, which is formed of a plurality of spur gears, axes of which are disposed parallel with the rotation shaft of the motor, and which are coupled with the rotation shaft of the motor;    a clutch case attached in a joined state at a side face of any one leg plate of the pair of leg plates;    a clutch accommodated in the clutch case, which is mechanically interposed between the motor and the winding shaft, which transmits rotation of the motor to the winding shaft and causes the winding shaft to rotate, and which blocks transmission of rotation which occurs at the winding shaft side and prevents this rotation being transmitted to the motor; and    a clutch gear section accommodated in the clutch case, the clutch gear section comprising a worm gear, an axis of which is disposed parallel with the rotation shaft of the motor and which is detachably coupled with a final spur gear of the motor gear section, and a worm wheel, which is disposed coaxially with the winding shaft, meshes with the worm gear and transmits rotation force of the worm gear to the clutch,    wherein the gear housing faces in an axial direction of the worm gear, and is assembled and fixed to an end face of the clutch case which is orthogonal to a direction of thickness of the clutch case, at a side which is opposite from the back plate.    
   
   
       2 . The webbing retractor recited in  claim 1 , wherein a coupling screw is provided at one end of the clutch case side of the winding shaft, and 
 the coupling screw passes through a leg plate at which the clutch case is attached, protrudes into the clutch case, and is connected with the clutch.    
   
   
       3 . The webbing retractor recited in  claim 1 , wherein the motor is disposed so that a distal end of an output direction of the rotation shaft thereof is oriented toward the gear housing.  
   
   
       4 . The webbing retractor recited in  claim 3 , wherein the output direction distal end of the rotation shaft of the motor passes through the gear housing and protrudes, and meshes with one of the spur gears of the motor gear section.  
   
   
       5 . The webbing retractor recited in  claim 1 , wherein a mounting stay is formed at the gear housing, and at least one positioning portion is provided at the mounting stay, 
 a positioning holding portion corresponding to the positioning portion is provided at the clutch case end face at which the gear housing is fixed, and    an assembly position of the gear housing is positioned by fixing the gear housing such that the positioning portion of the gear housing and the positioning holding portion of the clutch case end face correspond.    
   
   
       6 . The webbing retractor recited in  claim 5 , wherein the positioning portion is a boss and the positioning holding portion is a hole.