Patent ID: 7980503

Claim:
A webbing take-up device comprising: a take-up shaft around which a webbing for restraining a passenger is wound such that the webbing can be taken up and pulled out; a motor; and a clutch that is mechanically intervened between the motor and the take-up shaft, transmits the rotation of the motor to the take-up shaft to cause the take-up shaft to rotate, and cuts off the transmission of rotation arising at the take-up shaft side to prevent that rotation from being transmitted to the motor, wherein the clutch includes a rotating body that is disposed coaxially with respect to the take-up shaft and rotates as a result of the rotation of the motor being transmitted to the rotating body; sliders that are slidably engaged on the same rotating body and are configured to be relatively movable within a predetermined range on the rotating body and include push retention pieces that protrude toward one side in the moving direction; lock bars that are rotatably mounted on the rotating body and which have release pieces that protrude toward the push retention pieces of the sliders, and a spring that biases the lock bars toward an engaging direction at which the lock bars engage with the take-up shaft, wherein the lock bars are ordinarily retained in a positions where the release pieces of the lock bars engage with the push retention pieces of the slider so that the lock bars are maintained in a disengaged position at which the lock bars disengage from the take-up shaft, and when the rotating body rotates in a first direction about an axis of rotation of the rotating body, the lock bars move away from the sliders such that the retention therebetween is released and the lock bar engages with the take-up shaft as a result of a biasing force from the spring so that the rotation of the rotating body in the first direction about the axis thereof is transmitted to the take-up shaft, and when the rotating body rotates in a second direction about its axis that is in an opposite direction to said first direction, the lock bars move toward the sliders and the release pieces of the lock bar engages with the push retention pieces of the sliders so that the lock bars are retained in the disengaged position, and at least one of the push retention pieces of the sliders and the release pieces of the lock bars include retention portions that cause predetermined drag to arise with respect to the movement of the sliders away from the lock bars when the rotating body is stopped.