Webbing retractor

Abstract

To simplify the structure of a webbing retractor, at a second locking mechanism 44 of the webbing retractor, when a gas generator is not operated, a cam engages with an outer peripheral groove of a lock ring, and a limit load by a torsion shaft is made to be a high load. On the other hand, when the gas generator is operated, the cam is moved apart from the outer peripheral groove of the lock ring, and the limit load by the torsion shaft is made to be a low load. Because only the cam is interposed between the lock ring and a piston which is driven by the gas generator, the number of parts of the second locking mechanism can be reduced, and the structure of the second locking mechanism can be made simple.

1 . A webbing retractor comprising:
 a winding shaft on which a webbing, which can be applied to a vehicle occupant, is wound, the webbing being pulled out by the winding shaft being rotated in a pull-out direction;   a force limiter mechanism which, at a time of an emergency situation with respect to a vehicle, permits rotation of the winding shaft in the pull-out direction and limits a load, which is applied to the vehicle occupant from the webbing, to a limit load; and   a switching portion having a driving member which is configured to be driven at a time of an emergency situation with respect to the vehicle, an operating member directly operated by driving of the driving member, and a moving member which is engaged with the operating member and movement of which is permitted by operation of the operating member, the switching portion switching the limit load from a high load to a low load in response to the movement of the moving member being permitted.   
   
   
       2 . The webbing retractor of  claim 1 , wherein the winding shaft is hollow along the central axis thereof, the force limiter mechanism is accommodated within the winding shaft, and a first locking portion and the switching portion, which serves as a second locking portion, are coaxially connected at either end side of the winding shaft. 
   
   
       3 . The webbing retractor of  claim 1 , wherein the force limiter mechanism, serving as a first energy absorbing member, includes a first deforming portion which is connected between a portion which is joined to the winding shaft and the first locking portion and a second deforming portion which is connected between the portion which is joined to the winding shaft and the second locking portion (the switching portion), and is twistable by a rotational force in the pull-out direction of the winding shaft. 
   
   
       4 . The webbing retractor of  claim 1 , wherein a stopper accommodating hole for accommodating a stopper wire serving as a second energy absorbing member is formed in the winding shaft, one end portion of the stopper wire is disposed within a wire guiding portion which is formed at least either one of a first locking portion side end portion of the winding shaft and a winding shaft side end portion of the first locking portion, and the other end of the stopper wire is disposed within an accommodating hole formed in the second locking portion. 
   
   
       5 . The webbing retractor of  claim 1 , wherein only the operating member is interposed between the moving member and the driving member. 
   
   
       6 . The webbing retractor of  claim 1 , wherein the operating member is engaged with the moving member at one position. 
   
   
       7 . The webbing retractor of  claim 1 , wherein a supporting position of the operating member is disposed at a pull-out direction side of the moving member, with respect to an engaging position of the operating member with the moving member. 
   
   
       8 . A webbing retractor comprising:
 a winding shaft on which a webbing, which can be worn by a vehicle occupant, is wound, the webbing being pulled out by the winding shaft being rotated in a pull-out direction;   a force limiter mechanism which, at a time of an emergency situation with respect to a vehicle, permits rotation of the winding shaft in the pull-out direction and limits a load, which is applied to the vehicle occupant from the webbing, to a limit load; and   a switching portion having a driving member which is configured to be driven at a time of an emergency situation with respect to the vehicle, and a moving member which is engaged with the driving member and movement of which is permitted by driving of the driving member, the switching portion switching the limit load from a high load to a low load in response to the movement of the moving member being permitted.   
   
   
       9 . The webbing retractor of  claim 8 , wherein the winding shaft is hollow along the central axis thereof, the force limiter mechanism is accommodated within the winding shaft, and a first locking portion and the switching portion which serves as a second locking portion are coaxially connected at either end side of the winding shaft. 
   
   
       10 . The webbing retractor of  claim 8 , wherein the force limiter mechanism, serving as a first energy absorbing member, includes a first deforming portion which is connected between a portion which is joined to the winding shaft and the first locking portion and a second deforming portion which is connected between the portion which is joined to the winding shaft and the second locking portion (the switching portion), and is twistable by a rotational force in the pull-out direction of the winding shaft. 
   
   
       11 . The webbing retractor of  claim 8 , wherein a stopper accommodating hole for accommodating a stopper wire serving as a second energy absorbing member is formed in the winding shaft, one end portion of the stopper wire is disposed within a wire guiding portion which is formed at least either one of a first locking portion side end portion of the winding shaft and a winding shaft side end portion of the first locking portion, and the other end of the stopper wire is disposed within an accommodating hole formed in the second locking portion. 
   
   
       12 . The webbing retractor of  claim 8 , wherein nothing is interposed between the driving member and the moving member. 
   
   
       13 . The webbing retractor of  claim 8 , wherein the driving member is engaged with the moving member at one position. 
   
   
       14 . A webbing retractor comprising:
 a winding shaft on which a webbing, which can be worn by a vehicle occupant, is wound, the webbing being pulled out by the winding shaft being rotated in a pull-out direction;   a force limiter mechanism which, at a time of an emergency situation with respect to a vehicle, permits rotation of the winding shaft in the pull-out direction and limits a load, which is applied to the vehicle occupant from the webbing, to a limit load; and   a switching portion having an operating member which is configured to be operated at a time of an emergency situation with respect to the vehicle, and a moving member which is engaged with the operating member at one position with prevention and permission of movement thereof being alternated between by operation of the operating member, the switching portion switching the limit load between a high load and a low load in response to alternation between the operation and non-operation of the operating member.   
   
   
       15 . The webbing retractor of  claim 14 , wherein the winding shaft is hollow along the central axis thereof, the force limiter mechanism is accommodated within the winding shaft, and a first locking portion and the switching portion which serves as a second locking portion are coaxially connected at either end side of the winding shaft. 
   
   
       16 . The webbing retractor of  claim 14 , wherein the force limiter mechanism, serving as a first energy absorbing member, includes a first deforming portion which is connected between a portion which is joined to the winding shaft and the first locking portion and a second deforming portion which is connected between the portion which is joined to the winding shaft and the second locking portion (the switching portion), and is twistable by a rotational force in the pull-out direction of the winding shaft. 
   
   
       17 . The webbing retractor of  claim 14 , wherein a stopper accommodating hole for accommodating a stopper wire serving as a second energy absorbing member is formed in the winding shaft, one end portion of the stopper wire is disposed within a wire guiding portion which is formed at least either one of a first locking portion side end portion of the winding shaft and a winding shaft side end portion of the first locking portion, and the other end of the stopper wire is disposed within an accommodating hole formed in the second locking portion. 
   
   
       18 . A webbing retractor comprising:
 a winding shaft on which a webbing, which can be worn by a vehicle occupant, is wound, the webbing being pulled out by the winding shaft being rotated in a pull-out direction;   a force limiter mechanism which, at a time of an emergency situation with respect to a vehicle, permits rotation of the winding shaft in the pull-out direction and limits a load, which is applied to the vehicle occupant from the webbing, to a limit load; and   a switching portion having an operating member which is configured to be operated at a time of an emergency situation with respect to the vehicle, and a moving member which is engaged with the operating member with prevention and permission of movement thereof being alternated between by operation of the operating member, a supporting position of the operating member being disposed at a moving direction side with respect to an engaging position of the operating member, and the switching portion switching the limit load between a high load and a low load in response to alternation between the operation and non-operation of the operating member.   
   
   
       19 . The webbing retractor of  claim 18 , wherein the winding shaft is hollow along the central axis thereof, the force limiter mechanism is accommodated within the winding shaft, and a first locking portion and the switching portion which serves as a second locking portion are coaxially connected at either end side of the winding shaft. 
   
   
       20 . The webbing retractor of  claim 18 , wherein the force limiter mechanism, serving as a first energy absorbing member, includes a first deforming portion which is connected between a portion which is joined to the winding shaft and the first locking portion and a second deforming portion which is connected between the portion which is joined to the winding shaft and the second locking portion (the switching portion), and is twistable by a rotational force in the pull-out direction of the winding shaft. 
   
   
       21 . The webbing retractor of  claim 18 , wherein a stopper accommodating hole for accommodating a stopper wire serving as a second energy absorbing member is formed in the winding shaft, one end portion of the stopper wire is disposed within a wire guiding portion which is formed at least either one of a first locking portion side end portion of the winding shaft and a winding shaft side end portion of the first locking portion, and the other end of the stopper wire is disposed within an accommodating hole formed in the second locking portion. 
   
   
       22 . The webbing retractor of  claim 18 , wherein the operating member is engaged with the moving member at one position. 
   
   
       23 . A webbing retractor comprising:
 a winding shaft on which a webbing, which can be worn by a vehicle occupant, is wound, the webbing being pulled out by the winding shaft being rotated in a pull-out direction;   a force limiter mechanism which, at a time of an emergency situation with respect to a vehicle, permits rotation of the winding shaft in the pull-out direction and limits a load, which is applied to the vehicle occupant from the webbing, to a limit load; and   a switching portion having an operating member which is configured to be operated via pressure of a fluid at a time of an emergency situation with respect to the vehicle and with an operated state thereof being maintained via the pressure of the fluid, and a moving member, prevention and permission of movement thereof being alternated between by operation of the operating member, the switching portion switching the limit load between a high load and a low load in response to alternation between the operation and non-operation of the operating member.   
   
   
       24 . The webbing retractor of  claim 23 , wherein the winding shaft is hollow along the central axis thereof, the force limiter mechanism is accommodated within the winding shaft, and a first locking portion and the switching portion which serves as a second locking portion are coaxially connected at either end side of the winding shaft. 
   
   
       25 . The webbing retractor of  claim 23 , wherein the force limiter mechanism, serving as a first energy absorbing member, includes a first deforming portion which is connected between a portion which is joined to the winding shaft and the first locking portion and a second deforming portion which is connected between the portion which is joined to the winding shaft and the second locking portion (the switching portion), and is twistable by a rotational force in the pull-out direction of the winding shaft. 
   
   
       26 . The webbing retractor of  claim 23 , wherein a stopper accommodating hole for accommodating a stopper wire serving as a second energy absorbing member is formed in the winding shaft, one end portion of the stopper wire is disposed within a wire guiding portion which is formed at least either one of a first locking portion side end portion of the winding shaft and a winding shaft side end portion of the first locking portion, and the other end of the stopper wire is disposed within an accommodating hole formed in the second locking portion. 
   
   
       27 . The webbing retractor of  claim 23 , wherein the operating member is engaged with the moving member at one position.