Igniter and method of manufacturing an igniter for an inflator
A pyrotechnical igniter ( 100 ) for an inflator of a vehicle safety system comprises at least two contact pins ( 102 ) physically separated from each other by an electrically insulating compound and a bridge wire ( 110 ) connected to both contact pins ( 102 ) in an electrically conducting manner. A fastening portion ( 112 ) in which the bridge wire ( 110 ) is welded to the contact pins ( 102 ) is provided at each of the contact pins ( 102 ).
1. A pyrotechnical igniter ( 100 ) for an inflator of a vehicle safety system comprising
at least two contact pins ( 102 ) physically separated from each other by an electrically insulating compound and a bridge wire ( 110 ) connected to both contact pins ( 102 ) in an electrically conducting manner, wherein the bridge wire ( 110 ) consists of a nickel alloy with chromium at percentages of 11 to 24%, molybdenum at percentages of 12.5 to 17% and the specific resistance of the bridge wire ( 110 ) ranges from 0.25 to 3 Ωmm 2 /m,
wherein a fastening portion ( 112 ) in which the bridge wire ( 110 ) is welded to the contact pin ( 102 ) is provided at each contact pin ( 102 ),
and wherein in a top view a minimum distance (d) between a rim of the fastening portion ( 112 ) and the insulating compound is 0.01 to 0.5 mm.
2. The pyrotechnical igniter according to claim 1 , wherein each contact pin ( 102 ) is provided with a chlorine-free gold coating ( 126 ).
3. A method of manufacturing the pyrotechnical igniter according to claim 2 , comprising steps of:
introducing chlorine traps into a purifying solution and applying the gold layer in a galvanic process.
4. The pyrotechnical igniter according to claim 1 , wherein at least one of a pole body of the igniter and a cap outwardly closing off the igniter are made of plastic material having a substantially linear or cross-linked chain structure.
5. The pyrotechnical igniter according to claim 1 , wherein at least one of a pole body ( 104 ; 204 ) of the igniter ( 100 ; 200 ) and a cap ( 122 ; 222 ) outwardly closing off the igniter ( 100 ; 200 ) are made of thermosetting plastic.
6. The pyrotechnical igniter according to claim 1 , further comprising a pole body ( 104 ) including two contact pins ( 102 ) and a cap ( 122 ) outwardly closing off the igniter ( 100 ), wherein a seal ( 148 ) of a sealing compound is provided between at least one of the pole body ( 104 ) and the cap ( 122 ) and between the contact pins ( 102 ) and the pole body ( 104 ).
7. The pyrotechnical igniter according to claim 1 , further comprising a pole body ( 104 ) including the at least two contact pins ( 102 ) and a cap ( 122 ) outwardly closing off the igniter ( 100 ), the length (h) of the cap ( 122 ) in the longitudinal direction (A) of the igniter ( 100 ) being 7 to 15 mm.
8. The pyrotechnical igniter according to claim 1 , further comprising a pole body ( 104 ) including the at least two contact pins ( 102 ) and a cap ( 122 ) outwardly closing off the igniter ( 100 ), wherein the cap ( 122 ) is formed from two different plastic materials.
9. A method of manufacturing the pyrotechnical igniter especially according to claim 8 , comprising the step of fabricating the cap ( 122 ) by injection molding, wherein both plastic materials are introduced to an injection mold in the same processing step.
10. A pyrotechnical igniter ( 100 ) for an inflator of a vehicle safety system comprising
at least two contact pins ( 102 ) physically separated from each other by an electrically insulating compound and a bridge wire ( 110 ) connected to both contact pins ( 102 ) in an electrically conducting manner,
wherein a fastening portion ( 112 ) in which the bridge wire ( 110 ) is welded to the contact pin ( 102 ) is provided at each contact pin ( 102 ),
wherein in a top view a minimum distance (d) between a rim of the fastening portion ( 112 ) and the insulating compound is 0.01 to 0.5 mm, and
wherein the igniter further comprises a pole body ( 104 ) including the at least two contact pins ( 102 ) and a cap ( 122 ) outwardly closing off the igniter ( 100 ) and having a predetermined weakening zone ( 152 ) of reduced material thickness in which upon activation of the igniter ( 100 ) the material of the cap ( 122 ) yields under the internal pressure in the igniter ( 100 ), wherein the weakening zone ( 152 ) is arranged in a lateral circumferential wall ( 150 ) of the cap ( 122 ).
11. The pyrotechnical igniter according to claim 1 , wherein in the top view the minimum distance (d) between the rim of the fastening portion ( 112 ) and the insulating compound is 0.01 to 0.2 mm.
12. The pyrotechnical igniter according to claim 1 , wherein the bridge wire ( 110 ) further includes at least one of iron at a percentage of 0 to 7% and tungsten at a percentage of 0 to 4.5%.
13. The pyrotechnical igniter according to claim 7 , wherein the length (h) of the cap ( 122 ) in the longitudinal direction (A) of the igniter ( 100 ) is 8 to 12 mm.
14. A pyrotechnical igniter ( 100 ) for an inflator of a vehicle safety system comprising
at least two contact pins ( 102 ) physically separated from each other by an electrically insulating compound and a bridge wire ( 110 ) connected to both contact pins ( 102 ) in an electrically conducting manner,
wherein a fastening portion ( 112 ) in which the bridge wire ( 110 ) is welded to the contact pin ( 102 ) is provided at each contact pin ( 102 ),
wherein in a top view a minimum distance (d) between a rim of the fastening portion ( 112 ) and the insulating compound is 0.01 to 0.5 mm,
wherein the igniter further comprises a pole body ( 104 ) including the at least two contact pins ( 102 ) and a cap ( 122 ) outwardly closing off the igniter ( 100 ), wherein the cap ( 122 ) is formed from two different plastic materials, and
wherein the cap ( 122 ) includes an axial end wall ( 134 ) formed from a first plastic material and a cylindrical wall ( 136 ) integral with the axial end wall ( 134 ) and formed from a second plastic material harder than the first plastic material.