JP4576282B2 - Gas generator for airbag - Google Patents

Description

  The present invention relates to a gas generator for an air bag.

  The dual type gas generator whose output can be arbitrarily adjusted in accordance with the impact impact has a plurality of ignition / operation mechanisms and needs to operate independently of each other. Therefore, it is necessary to have a structure in which one ignition / operation mechanism does not affect other ignition / operation mechanisms.

  Patent Document 1 discloses a gas generator in which a pressurized gas is arranged inside a housing and ignition devices are installed at both ends. A small-diameter portion is formed at the center of the housing, and a gas discharge port closed with a rupturable plate is provided at one of the portions, and a cup-shaped diffuser is provided to cover the gas discharge port. The diffuser has a gas nozzle on the peripheral wall portion, and is attached in a state protruding from the housing.

  Patent Document 2 discloses a gas generator in which two chambers 16 and 18 containing a pressurized medium are attached via a common connection ring 30. The chambers 16 and 18 are closed by rupturable plates 42 and 44 arranged in close proximity to each other, and the central chamber 32 and the chambers 16 and 18 are isolated. A heating device 22 is attached to each of the chambers 16 and 18, and the operation timing of each heating device 22 changes depending on the strength of the impact. The pressure in the chamber 16 or 18 is increased by the operation of the heating device 22, and the rupturable plate 42 or 44 is cleaved. A plurality of gas discharge holes 46 are formed in the ring 30.

In Patent Document 3, two chambers 70 and 72 containing pressurized gas are formed by a partition wall 74 in which a small hole 78 is formed (in the drawing, the small hole 78 is arranged at the center of the partition wall 74). An explosive 68 is installed on the rupturable plate 66 in the front chamber 70, and the rupturable plate 66 is cleaved by impact. On the other hand, the propellant 80 is also arranged in the central portion of the rear chamber 72, and additional gas is generated by this combustion, and the pressure of the rear chamber 72 is increased. As a result, gas flows into the front chamber 70 through the small hole 78.
USP 5,794973 USP 5,582,428 USP 3961806

  In patent document 1, since the diffuser part protrudes, attachment workability | operativity may be impaired and the jet direction of gas is also restrict | limited. Also, the operation of one igniter may affect the other igniter. Further, the protrusions are bulky during storage and transportation, so there is a lot of waste when packed in a box.

  In patent document 2, it is a system which connects two housings. If one of the two rupture plates facing each other in the vicinity is destroyed by the operation of one igniter, the other may be destroyed. There is no certainty. Also, the two housings must be filled with gas separately.

  In patent document 3, since it is isolate | separated into two chambers by the fixed partition and the magnitude | size of the capacity | capacitance of two chambers is restrict | limited, it cannot respond to various requests | requirements. Moreover, since the fixed partition has a small hole in an open state, the other igniter may be affected by the operation of one igniter.

  The present invention has no portion protruding outward in the width direction, has an outer surface having a substantially flat shape, is easy to fill with gas, and can emit gas radially when activated. It is another object of the present invention to provide a gas generator for an air bag in which the operation of one ignition device does not affect the operation of another ignition device.

As a means for solving the problems, the present invention
One cylindrical housing filled with pressurized gas, and one or more ignition devices attached to the cylindrical housing,
The cylindrical housing has a reduced diameter portion formed of an annular convex portion protruding inward;
The reduced diameter portion has one first gas discharge port closed with a rupturable plate,
The reduced diameter portion including the first gas discharge port is surrounded by a cylindrical diffuser portion having a plurality of second gas discharge ports,
An airbag gas generator in which an outer diameter including a portion surrounded by the diffuser portion is approximate to an outer diameter of the cylindrical housing.

  The cylindrical housing is in a sealed state so that pressurized gas can be filled and held, and the cross section in the width direction is circular, but may be oval or polygonal.

  The ignition device may be composed of only an electric igniter, a combination of an electric igniter and a gas generant molding, or a combination of these and other members.

  The reduced diameter portion is an annular convex portion projecting inward (annular concave portion as viewed from the outer surface), and is an annular convex in which 75% or more in the circumferential direction (ratio based on the length of one circumference) is continuous. If it is a part, the convex part may not be formed in part, but it is preferably an annular convex part (100% in the circumferential direction) continuous in the entire circumferential direction.

  The reduced diameter portion is preferably located at the central portion in the axial direction, but may be formed at a position offset toward one end side.

  For the reduced diameter portion, a method of forming an annular concave portion (groove portion) by pressing the cylindrical housing from the outside can be applied, or another member having a small diameter can be combined.

  The diffuser portion has a cylindrical shape, and the outer diameter including the portion surrounded by the diffuser portion approximates the outer diameter of the cylindrical housing (the outer diameter surrounded by the diffuser portion = housing outer diameter + diffuser). Part thickness). Therefore, the outer surface of the cylindrical housing and the outer surface of the diffuser part are substantially flush with substantially no projection. For this reason, in comparison with a gas generator having protrusions in the width direction as in Patent Document 1, it is easy to attach the airbag and the gas generator in the module case, and can be used for storage and transportation. Workability is also good.

  The reduced diameter portion is provided with one first gas discharge port, and the diffuser portion is provided with a plurality of second gas discharge ports arranged in the circumferential direction. The ejected gas is ejected radially while moving in the circumferential direction, and inflates the airbag evenly. The gas may be ejected in a specific direction by adjusting the position of the second gas discharge port.

  Further, since the inside of the cylindrical housing is one space, it is not necessary to separately fill the pressurized gas into the two spaces as in Patent Document 2, and the filling operation of the pressurized gas may be performed once.

  According to another aspect of the present invention, when there are two or more ignition devices, at least one ignition device includes a gas generating agent and an electric igniter in a combustion chamber housing having a plurality of gas holes. A gas generator for an air bag according to claim 1 is provided.

  In the case of having two igniters, if two operate at the same time, one may operate first, while the other operates late, only one may operate. Therefore, in the case of having two ignition devices, by providing the combustion chamber housing in one ignition device (an ignition device that may operate after a delay), the operation of the ignition device that may be operated earlier is delayed. The operation of the ignition device that may operate may be prevented from being adversely affected.

The present invention provides other means for solving the problems,
A gas generator for an air bag according to claim 1,
The cylindrical housing is partitioned into two spaces by an axially movable partition wall having a communication hole,
In each of the two spaces, one or more ignition devices are arranged,
When one ignition device arranged in one space is activated, the partition wall moves to the opposite side in the axial direction, and the communication hole is blocked by contacting a part of the fixing member arranged in the other space. ,
Provided is a gas generator for an air bag in which when the other ignition device disposed in the other space is operated, the partition wall is moved in the opposite axial direction and the communication hole is opened. To do.

  The fixing member referred to in the present invention is a wall or cup that partitions a space where the ignition device is located from another space, and has a ventable hole.

  In the gas generator of the present invention, by having a movable partition wall, the same operational effects as those of the first aspect of the present invention can be obtained, and the following operational effects can also be obtained.

  When the inside of the cylindrical housing is one space, there is a possibility that heat, shock waves, etc. generated by the operation of one ignition device may contact the other ignition device and cause malfunction of the other ignition device (patent) Literature 1, 3).

  However, in the present invention, due to the operation of one ignition device, the partition wall moves to the opposite side in the axial direction (the other ignition device side) and abuts against the fixing member disposed in the other space, and the communication hole of the partition wall Is closed, so that heat, shock waves, etc. do not contact the other ignition device. Further, since the partition wall is movable, modification according to various requirements is facilitated as compared with the case where a fixed partition wall is used as in Patent Document 3.

  According to another aspect of the present invention, there is provided the gas generator for an air bag according to claim 3, wherein the partition wall is disposed between the reduced diameter portion of the cylindrical housing and the other ignition device. .

The present invention provides other means for solving the problems,
The other ignition device is configured such that a gas generating agent and an electric igniter are accommodated in a combustion chamber housing having a plurality of gas holes,
The combustion chamber housing is the fixed member;
The gas generator for an air bag according to claim 3 or 4, wherein the partition wall is brought into contact with a wall surface of the combustion chamber housing having no gas holes.

  The combustion chamber housing is a member for separating the ignition device from other spaces, and can be a disk member that partitions the cylindrical housing in the radial direction, a cup-shaped member that surrounds the ignition device, or the like. When the combustion chamber housing is a cup-shaped member, gas holes can be provided at desired positions on the peripheral surface and top surface, but a plurality of gas holes may be provided on the peripheral surface and no gas holes may be provided on the top surface. preferable. By such a combustion chamber housing functioning as a fixed member, it is possible to prevent the influence of the operation of one ignition device from affecting the other ignition device.

The present invention provides other means for solving the problems,
A gas generator for an air bag according to claim 1,
The cylindrical housing is formed of a first partition and a cylindrical housing by an axially movable first partition having a first communication hole and a fixed second partition having a second communication hole. Partitioned into a space, a second space formed by the second partition and the cylindrical housing, and a third space formed by the first partition, the second partition and the cylindrical housing,
The first communication hole of the first partition and the second communication hole of the second partition are formed at positions that do not overlap with each other in the axial direction;
One or more first ignition devices and second ignition devices are arranged in the first space and the second space, respectively.
When the first ignition device disposed in the first space is activated, the first partition wall moves to the opposite side in the axial direction and comes into contact with the second partition wall so that the first communication hole and the second communication hole are in contact with each other. Is blocked,
When one or more second ignition devices disposed in the second space are activated, the first partition contacting the second partition moves to the opposite side in the axial direction. Provided is a gas generator for an air bag in which a second communication hole is opened.

  In the present invention, before the operation, the third space exists between the movable first partition and the fixed second partition. However, after the first ignition device is operated, the first partition is moved. The first partition is pressed by the second partition, and the third space disappears. And since the 1st communicating hole of the 1st partition and the 2nd communicating hole of the 2nd space are formed in the position which does not mutually overlap in the direction of an axis, the 1st communicating hole is obstructed by the 2nd partition face, and the 2nd The communication hole is closed by the first partition wall surface. Therefore, heat, shock waves, etc. do not flow into the second ignition device side. After the operation of the second ignition device, the first partition moves to the opposite side, so that the third space is restored and a gas passage is secured.

The present invention provides other means for solving the problems,
The reduced diameter portion of the cylindrical housing is an annular convex portion protruding inward, and is composed of two inclined portions facing each other in the axial direction and a flat surface portion between the two inclined portions,
The first partition wall is disposed on a flat surface portion of the reduced diameter portion, and the flat surface portion has a stopper portion that restricts movement of the first partition wall in the axial direction;
The gas generator for an air bag according to claim 6, wherein the second partition wall is fixed to one inclined surface portion of the reduced diameter portion.

  During the operation of the second ignition device, the first partition moves in the axial direction and the third space is restored. However, at this time, it is sufficient if the third space for securing the gas passage can be formed, and unlimited movement is allowed. In such a case, the first gas discharge port may be blocked and returned to obstruct gas discharge. Therefore, the movement of the first partition wall in the axial direction is limited to ensure the gas discharge path.

  The gas generator for an air bag of the present invention can be applied to both a combination of a pressurized gas and a combustion gas of a gas generating agent as a means for inflating an air bag, and one using only a pressurized gas. It can be used as various known gas generators for seats and the like.

  Since the gas generator for an air bag of the present invention has no protrusion on the outer surface of the cylindrical housing, it can be easily attached to the module case, is not bulky during storage and transportation, and has good workability.

  In the gas generator for an air bag of the present invention, when two or more ignition devices are separately arranged, the operation of one ignition device does not adversely affect other ignition devices.

(1) Gas generator of FIG. 1 FIG. 1 is an axial sectional view of a gas generator 10 of the present invention.

  The cylindrical housing 11 has a circular cross section in the width direction and is made of metal having pressure resistance. One space 12 in the cylindrical housing 11 is filled with a pressurized gas made of argon, helium or the like (filling pressure is about 30,000 to 67,000 kPa).

  A first ignition device 20 is attached to one end side opening of the cylindrical housing 11. The first ignition device 20 includes an electric first igniter 22 and a gas generating agent molded body (not shown), which are accommodated in a combustion chamber housing 25.

  The first igniter 22 is attached to one end side opening of the cylindrical housing 11 in a state of being fitted into the boss 21, and the joint 23 between the cylindrical housing 11 and the boss 21 is welded. The opening of the boss 21 is closed by the first rupturable plate 24, and the first igniter 22 and the first rupturable plate 24 face each other.

  The boss 21 including the first igniter 22 is surrounded by a cup-shaped first combustion chamber housing 25, and the inside is a first combustion chamber 27. The opening of the first combustion chamber housing 25 is fitted into the step portion of the boss 21. The first combustion chamber housing 25 has a plurality of first gas holes 26 on the peripheral surface 25a, but there is no first gas hole 26 on the top surface 25b. Pressurized gas is also present in the first combustion chamber housing 25.

  The first combustion chamber 27 is filled with a known gas generant molded body (not shown), the capacity is adjusted according to the filling amount of the gas generant molded body, and the peripheral surface of the boss 21 A movable retainer 28 is disposed between the first combustion chamber housing 25 and the peripheral surface of the first combustion chamber housing 25 to prevent the gas generating agent molded body from entering. The retainer 28 has a plurality of holes 29 through which heat and shock waves generated by the operation of the first igniter 22 pass.

  A second ignition device 30 is attached to the opening on the other end side of the cylindrical housing 11. The second ignition device 30 includes an electric second igniter 32 and a gas generating agent molded body (not shown), which are accommodated in a combustion chamber housing 35.

  The 2nd igniter 32 is attached to the one end side opening part of the cylindrical housing 11 in the state inserted by the boss | hub 31, and the junction part 33 of the cylindrical housing 11 and the boss | hub 31 is welded. The opening of the boss 31 is closed by the second rupturable plate 34, and the second igniter 32 and the second rupturable plate 34 face each other.

  The boss 31 including the second igniter 32 is surrounded by a cup-shaped second combustion chamber housing 35, and the inside is a second combustion chamber 37. The opening of the second combustion chamber housing 35 is fitted into the stepped portion of the boss 31. The second combustion chamber housing 35 has a plurality of second gas holes 36 on the peripheral surface 35a, but there is no second gas hole 36 on the top surface 35b. Pressurized gas is also present in the second combustion chamber housing 35.

  The second combustion chamber 37 is filled with a known gas generant molded body (not shown). The capacity is adjusted according to the amount of the gas generant molded body and the peripheral surface of the boss 31 is adjusted. And a movable retainer 38 for preventing the gas generating agent molded body from entering between the second combustion chamber housing 35 and the peripheral surface of the second combustion chamber housing 35. The retainer 38 has a plurality of holes 39 for allowing heat and shock waves generated by the operation of the second igniter 32 to pass therethrough.

  A reduced diameter portion 40 is provided at a position near the second ignition device 30 of the cylindrical housing 11. The reduced diameter portion 40 is composed of an annular convex portion having two slope portions 41 and 42 facing each other in the axial direction and a flat surface portion 43 between the two slope portions 41 and 42. The reduced diameter portion 40 is formed around the cylindrical housing 11.

  The flat surface portion 43 of the reduced diameter portion 40 is provided with one first gas discharge port 45, and the first gas discharge port 45 is closed with a discharge port rupturable plate 46. The reduced diameter portion 40 including the first gas discharge port 45 is surrounded by a cylindrical diffuser portion 47 having a plurality of second gas discharge ports 48. The cylindrical diffuser portion 47 is welded on the contact surface with the cylindrical housing 11.

  The outer diameter including the portion surrounded by the diffuser portion 47 is the sum of the outer diameter of the cylindrical housing 11 and the thickness of the diffuser portion 47, and is substantially flat as shown in the figure. The diffuser portion 47 is for preventing the fragments of the discharge port rupturable plate 46 from being scattered, and since a wire net or the like can be used, a thickness of about 0.5 to 1.5 mm is sufficient.

  The flat surface portion 43 has a gas filling hole closed with a pin 49. When the gas generator 10 is assembled, the gas filling hole is closed by welding the flat surface portion 43 and the pin 49 together after filling the gas from the gap between the pins 49 inserted into the gas filling hole. By providing the gas filling hole closed with the pin 49 in the flat surface portion 43, the end portion of the pin 49 does not protrude from the outer surface of the cylindrical housing 11.

  Next, operation | movement of the gas generator 10 for airbags is demonstrated. A case will be described where the first igniter 22 is activated first and the second igniter 32 is activated later.

  Due to the operation of the first igniter 22, the first rupturable plate 24 is destroyed, heat and shock waves flow into the first combustion chamber 27, and the first gas generating agent is ignited and combusted. The high-temperature gas generated by the combustion of the first gas generant molded body flows into the internal space 12 from the gas hole 26 of the first combustion chamber housing 27 and increases the pressure.

  As the pressure in the internal space 12 rises, the discharge port rupturable plate 46 is broken and the first gas discharge port 45 is opened. The mixed gas of the pressurized gas and the high temperature gas ejected from the first gas discharge port 45 is discharged radially from the second gas discharge port 48 through the diffuser portion 47 while moving in the circumferential direction in the reduced diameter portion 40. The airbag is inflated. In this process, the high temperature gas that has flowed out of the first combustion chamber 27 does not ignite and burn the second gas generating agent molded body due to the presence of the second combustion chamber housing 35.

  The second igniter 32 is operated with a slight delay, the second rupturable plate 34 is broken, heat and shock waves flow into the second combustion chamber 37, and the second gas generant molded body is ignited and burned. The high-temperature gas generated by the combustion of the second gas generant molded body flows into the internal space 12 from the gas hole 36 of the second combustion chamber housing 35, and then passes through the opened first gas exhaust port 46 to 2 The gas is discharged radially from the gas outlet 48 and the airbag is further inflated.

(2) Gas Generator in FIG. 2 FIG. 2 (a) is an axial sectional view of the gas generator 100 of the present invention, and FIG. 2 (b) illustrates the operation of the gas generator 100 in FIG. 2 (a). It is a fragmentary sectional view for doing. Since FIG. 2 has a structure similar to that of the gas generator 10 of FIG. 1, only different parts will be described. In FIG. 2, the same numbers as those in FIG. 1 mean the same.

  The inside of the cylindrical housing 11 is partitioned into a first space 12a and a second space 12b by a disk-shaped partition wall 50 that is movable in the axial direction. Since the circular communication hole 52 is provided in the center of the disk-shaped partition wall 50, the first space 12a and the second space 12b are a single space.

  The disc-shaped partition wall 50 is disposed between the reduced diameter portion 40 and the second ignition device 30. The axial movement of the disk-shaped partition wall 50 is limited to the range of the inclined surface portion 42 of the reduced diameter portion 40 and the top surface 35 b of the second combustion chamber housing 35.

  The disc-shaped partition wall 50 has a flange portion 51 at the peripheral portion, and is fitted into the flange portion 51 so as to press the inner peripheral surface of the cylindrical housing 11.

  Next, the operation of the air bag gas generator 100 will be described. A case will be described where the first igniter 22 is activated first and the second igniter 32 is activated later.

  Due to the operation of the first igniter 22, the first rupturable plate 24 is destroyed, heat and shock waves flow into the first combustion chamber 27, and the first gas generant molded body is ignited and burned. The high-temperature gas generated by the combustion of the first gas generating agent flows into the first space 12a from the gas hole 26 of the first combustion chamber housing 25 and raises the pressure.

  Due to the increase in pressure in the first space 12a, the disk-shaped partition wall 50 is pressed, moves in the axial direction, and comes into contact with the top surface 35a of the second combustion chamber housing 35 (FIG. 2B). At this time, the communication hole 52 is closed by the top surface 35a.

  After that, the discharge port rupturable plate 46 is broken and the first gas discharge port 45 is opened due to an increase in pressure in the first space 12a. The mixed gas of the pressurized gas and the high temperature gas ejected from the first gas discharge port 45 is discharged radially from the second gas discharge port 48 through the diffuser portion 47 while moving in the circumferential direction in the reduced diameter portion 40. The airbag is inflated. In this process, the high temperature gas flowing out from the first combustion chamber 27 does not ignite and burn the second gas generant molded body due to the presence of the disk-shaped partition walls 50.

  The second igniter 32 is operated with a slight delay, the second rupturable plate 34 is broken, heat and shock waves flow into the second combustion chamber 37, and the second gas generant molded body is ignited and burned. The high-temperature gas generated by the combustion of the second gas generating agent molded body flows into the second space 12b from the gas hole 36 of the second combustion chamber housing 35 and increases the pressure.

  Due to the pressure increase in the second space 12b, the disk-shaped partition wall 50 is pressed, moves in the axial direction, and returns to the state shown in FIG. As a result, since the communication hole 52 is opened, the mixed gas of the pressurized gas and the high temperature gas in the second space 12b passes through the first gas exhaust port 46 opened through the first space 12a, The air is discharged radially from the second gas discharge port 48, and the airbag is further inflated.

(3) Gas Generator of FIG. 3 FIG. 3 (a) is an axial sectional view of the gas generator 200 of the present invention, and FIG. 3 (b) illustrates the operation of the gas generator 200 of FIG. 3 (a). It is a fragmentary sectional view for doing. Since FIG. 3 has a structure similar to that of the gas generator 10 of FIG. 1, only different parts will be described. In FIG. 3, the same numbers as those in FIG. 1 mean the same.

  In the cylindrical housing 11, the first space 12 a formed by the first partition 60 and the cylindrical housing 11, and the second partition 70 are fixed to the first partition 60 that is movable in the axial direction and the second partition 70 before the operation. A second space 12b formed by the two partition walls 70 and the cylindrical housing 11 and a third space 12c formed by the first partition wall 60, the second partition wall 70, and the cylindrical housing 11 are partitioned.

  The first partition wall 60 has a disc shape, and has a flange portion 61 at the peripheral portion. The flange portion 61 presses the inner peripheral surface of the tubular housing 11 (the flat surface portion 43 of the reduced diameter portion 40). It is inserted. A part of the first partition wall 60 is provided with a circular first communication hole 62.

  The second partition wall 70 has a disk shape, has a flange portion 71 at the peripheral edge portion, and is fixed to the inclined surface portion 42 of the reduced diameter portion 40 by welding at the flange portion 71. A part of the second partition wall 70 is provided with a circular second communication hole 72.

  A pin 49 that closes the gas filling hole protrudes from the flat surface portion 43, and this pin 49 serves as a stopper portion. Therefore, the movement of the first partition wall 60 in the axial direction is within the range from the pin 49 to the second partition wall 70. Limited to The length of the pin 49 is adjusted to such an extent that the gas filling hole can be closed and the movement of the first partition wall 60 in the axial direction can be prevented.

  The first communication hole 62 of the first partition wall 60 and the second communication hole 72 of the second partition wall 70 are formed at positions that do not overlap with each other in the axial direction. Therefore, when the first partition wall 60 and the second partition wall 70 are brought into contact with each other, the first communication hole 62 is in contact with the wall surface of the second partition wall 70, and the second communication hole 72 is in contact with the wall surface of the first partition wall 60. Therefore, both the first communication hole 62 and the second communication hole 72 are closed.

  Next, the operation of the air bag gas generator 200 will be described. A case will be described where the first igniter 22 is activated first and the second igniter 32 is activated later.

  Due to the operation of the first igniter 22, the first rupturable plate 24 is destroyed, heat and shock waves flow into the first combustion chamber 27, and the first gas generant molded body is ignited and burned. The high-temperature gas generated by the combustion of the first gas generating agent flows into the first space 12a from the gas hole 26 of the first combustion chamber housing 27 and raises the pressure.

  As the pressure in the first space 12a increases, the first partition wall 60 is pressed, moves in the axial direction, contacts the second partition wall 70, and the third space 12c disappears [FIG. 3 (b)]. At this time, as described above, the first communication hole 62 and the second communication hole 72 are closed.

  After that, the discharge port rupturable plate 46 is broken and the first gas discharge port 45 is opened due to an increase in pressure in the first space 12a. The mixed gas of the pressurized gas and the high temperature gas ejected from the first gas discharge port 45 is discharged radially from the second gas discharge port 48 through the diffuser portion 47 while moving in the circumferential direction in the reduced diameter portion 40. The airbag is inflated. In this process, the high temperature gas flowing out from the first combustion chamber 27 does not ignite and burn the second gas generating agent due to the presence of the first partition wall 60 and the second partition wall 70.

  The second igniter 32 is operated with a slight delay, the second rupturable plate 34 is broken, heat and shock waves flow into the second combustion chamber 37, and the second gas generant molded body is ignited and burned. The high-temperature gas generated by the combustion of the second gas generating agent molded body flows into the second space 12b from the gas hole 66 of the second combustion chamber housing 35 and increases the pressure.

  The first partition wall 60 moves in the axial direction by being pressed at the portion of the second communication hole 72 due to the pressure increase in the second space 12b. The first partition wall 60 stops in contact with the pin 49, the third space 12c is restored, and returns to the state shown in FIG. As a result, since the first communication hole 62 and the second communication hole 72 are opened, the mixed gas of the pressurized gas and the high temperature gas in the second space 12b passes through the third space 12c and the first space 12a. The air is exhausted radially from the second gas exhaust port 48 through the opened first gas exhaust port 46, and the airbag is further inflated.

The axial sectional view of the gas generator for airbags. (A) is an axial sectional view of another gas generator for an air bag, and (b) is a partial sectional view for explaining the operation of (a). (A) is an axial sectional view of another gas generator for an air bag, and (b) is a partial sectional view for explaining the operation of (a).

Explanation of symbols

10, 100, 200 Gas generator 11 Tubular housing 12, 12a, 12b, 12c Internal space 20 First igniter 22 First igniter 25 First combustion chamber housing 30 Second igniter 32 Second igniter 35 Second Combustion chamber housing 40 Reduced diameter portion 45 First gas discharge port 47 Diffuser portion 50 Disc-shaped partition wall 52 Communication hole 60 First partition wall 62 First communication hole 70 Second partition wall 72 Second communication hole

Claims (5)

One cylindrical housing (11) filled with pressurized gas, and two igniters attached to the cylindrical housing (11),
The cylindrical housing (11) has a reduced diameter portion (40) composed of an annular convex portion protruding inward,
The reduced diameter portion (40) has one first gas outlet (45) closed by a rupturable plate (46),
The reduced diameter portion (40) including the first gas discharge port (45) is surrounded by a cylindrical diffuser portion (47) having a plurality of second gas discharge ports (48),
The outer diameter including the part surrounded by the diffuser part (47) is the sum of the outer diameter of the cylindrical housing (11) and the thickness of the diffuser part (47),
The cylindrical housing (11) is partitioned into a first space (12a) and a second space (12b) by an axially movable partition wall (50) having a communication hole (52) ,
A first igniter (22) is disposed in the first space (12a), and a second igniter (32) is disposed in the second space (12b) ;
When the first igniter (22) disposed in the first space (12a) is activated, the partition wall (50) moves to the axially opposite side with respect to the first igniter (22) , and the second space ( The communication hole (52) is closed by contacting the fixing member (35) arranged in 12b) ,
When the second igniter (32) disposed in the second space (12b) is activated, the partition wall (50) moves to the axially opposite side with respect to the second igniter (32), and the communication hole Gas generator for airbag (100) , wherein (52) is opened. The partition wall is disposed between the reduced diameter portion and the second igniter of the cylindrical housing, a gas generator for an air bag according to claim 1, wherein. The second igniter includes a gas generating agent and an electric igniter housed in a combustion chamber housing having a plurality of gas holes.
The combustion chamber housing is the fixed member;
The gas generator for an air bag according to claim 1 or 2 , wherein the partition wall is brought into contact with a wall surface of the combustion chamber housing having no gas holes. One cylindrical housing (11) filled with pressurized gas, and two igniters (22, 32) attached to the cylindrical housing (11),
The cylindrical housing (11) has a reduced diameter portion (40) composed of an annular convex portion protruding inward,
The reduced diameter portion (40) has one first gas outlet (45) closed by a rupturable plate (46),
The reduced diameter portion (40) including the first gas discharge port (45) is surrounded by a cylindrical diffuser portion (47) having a plurality of second gas discharge ports (48),
The outer diameter including the part surrounded by the diffuser part (47) is the sum of the outer diameter of the cylindrical housing (11) and the thickness of the diffuser part (47),
The cylindrical housing (11) includes an axially movable first partition (60) having a first communication hole (62 ) and a fixed second partition (70) having a second communication hole (72 ). Thus, a first space (12a) formed by the first partition wall (60) and the cylindrical housing (11) , a second space (12b) formed by the second partition wall (70) and the cylindrical housing (11 ) , And the first partition wall (60) , the second partition wall (70) , and the third space (12c) formed by the cylindrical housing (11) ,
The first communication hole (62) of the first partition wall (60) and the second communication hole (72) of the second partition wall (70) are formed at positions that do not overlap with each other in the axial direction.
Wherein the first space (12a) and said second space (12b), and respective ones of the first igniter (22) and the second igniter (32) is arranged,
When the first igniter (22) disposed in the first space (12a) is activated, the first partition wall (60) moves to the axially opposite side with respect to the first igniter (22) , and The first communication hole (62) and the second communication hole (72) are closed by contacting the second partition wall (70) ,
When the second igniter disposed in the second space (12b) (32) is actuated, the second partition wall (70) in contact with said first partition wall (60) of the second igniter (32) On the other hand, the gas generator (200) for an airbag, wherein the first communication hole (62) and the second communication hole (72) are opened by moving to the opposite side in the axial direction. The reduced diameter portion of the cylindrical housing is an annular convex portion protruding inward, and is composed of two inclined portions facing each other in the axial direction and a flat surface portion between the two inclined portions,
The first partition wall is disposed on a flat surface portion of the reduced diameter portion, and the flat surface portion has a stopper portion that restricts movement of the first partition wall in the axial direction;
The gas generator for an air bag according to claim 4 , wherein the second partition wall is fixed to one inclined surface portion of the reduced diameter portion.

Images