Gas generator for air bag and air bag apparatus

Abstract

When a gas generating agent 9 a inside a first combustion chamber 5 a is burnt, a gas generating agent 9 b is prevented from being burnt by function of a metal thin plate 11 closing a communication hole 10 with a second combustion chamber 5 b . A cup 1190 having a hole 1191 is covered on an igniter 1112 , and the flame thereof advances into a transfer charge 1116 straightly in a narrow width. Accordingly, since the transfer charge 1116 is burnt completely, sufficient flame for burning a gas generating agent 1109 can be generated securely. A communication hole 3010 between a first combustion chamber 3005 a and a second combustion chamber 3005 b is closed by double-layered seal tape 3011 laminated through an adhesive layer. After activation, the seal tapes 3011 are not ruptured due to increase in the internal pressure of the first combustion chamber 3005 a , but they are peeled off easily due to increase in the internal pressure of the second combustion chamber 3005 b.

1 . A gas generator for an air bag, comprising a housing having a gas discharge port, and an ignition means to be actuated by the impact and a gas generating means which is to be ignited and burnt by the ignition means for generating a combustion gas to inflate an air bag, the ignition means and the gas generating agent stored in the housing, wherein the ignition means includes an igniter and a transfer charge in an ignition means accommodating chamber, and the charge density of the transfer charge is in the range of 0.1 to 5 g/cm3.  
   
   
       2 . A gas generator for an air bag, comprising a housing having a gas discharge port, and an ignition means to be actuated by the impact and a gas generating means which is to be ignited and burnt by the ignition means for generating a combustion gas to inflate an air bag, the ignition means and the gas generator stored in the housing, wherein the ignition means includes an igniter and a transfer charge in an ignition means accommodating chamber, the charge density of the transfer charge is in the range of 0.1 to 5 g/cm3, and a ratio [(A+B)/A] of a volume (A) of the space where the transfer charge occupies inside the ignition means accommodating chamber and the volume (B) of the remaining space in the ignition means accommodating chamber is in the range of 1.05 to 20.  
   
   
       3 . A gas generator for an air bag according to  claim 1  or  2 , wherein a transfer charge is stored in a transfer charge accommodating chamber provided independently inside the ignition means accommodating chamber.  
   
   
       4 . A gas generator for an air bag according to  claim 1  or  2 , wherein two or more combustion chambers storing the gas generating means are arranged in the housing, and two or more ignition means for igniting and burning the respective gas generating means are arranged in the two or more combustion chambers.  
   
   
       5 . An air bag apparatus comprising a gas generator for an air bag, an impact sensor which senses the impact to actuate the gas generator, an air bag to which the gas generated in the gas generator is introduced to be inflated, and a module case which stores the air bag, wherein the gas generator for an air bag is the gas generator for an air bag according to  claim 1  or  2 .