Pretensioner and assembly method thereof, seat belt retractor, seat belt device

Abstract

A plurality of driving force transmitting members, a piston, a spring and a gas generator are inserted into the pipe from the end of the pipe where the gas generator is mounted. The gas generator is press-fitted in the pipe while the flat faces thereof are deformed by a pair of protrusions of the pipe. Accordingly, the gas generator is temporarily held by the protrusions of the pipe. Then, one end of the pipe is firmly pressed and the gas generator is mounted in the pipe.

Description

technical field [0001] The present invention relates to various technical fields of pretensioning that rotates a spool in a seat belt winding direction at the initial stage of an emergency when a large deceleration of a predetermined value or more is applied to a vehicle, such as when a vehicle collides, and increases a restraint force on an occupant by the seat belt. A seat belt retractor having the pretensioner and preventing the pull-out of the seat belt in an emergency, a seat belt device having the seat belt retractor and restraining the occupant through the seat belt in an emergency, and a pretensioner The assembly method of the device. Background technique [0002] Conventionally, a seat belt device installed in a vehicle such as a motor vehicle restrains the occupant by the seat belt to prevent the occupant from inertial movement from the seat during the above-mentioned emergency. The seat belt device has a seat belt retractor, and the seat belt retractor performs t...

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Problems solved by technology

[0010] However, if the piston is formed into a shape such as a cylinder or a barrel, the piston becomes longer in the axial direction

Therefore, there is a problem that when the piston is inserted into the three-dimensionally curved duct from the opposite side of the installation position of the gas generator as in the prior art, it is difficult for the piston that is long in the axial direction to fit in the three-dimensionally curved duct. Moves smoothly, making pretensioner assembly difficult

However, for the operation of riveting the one end of the conduit after inserting the gas generator into the conduit as described in the above-mentioned Japanese Patent Document 3, the gas generator is riveted by the gas generator in the conduit when riveting the one end of the conduit. The force of the spring is biased in the direction of falling out from the guide tube, so it is difficult to perform the riveting process smoothly and stably

Therefore, there is a problem that when assembling the pretensioner, when the balls, the piston, the spring, and the gas generator are inserted into the pipe from one end of the pipe in order, the installation workability of the gas generator is poor.

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