JP2008213529A - Inflater - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inflater capable of suppressing occurrence of unevenness in the time required from the start of squib operation to the start of discharge of gas for inflation to make the time substantially fixed. <P>SOLUTION: This inflater 1 of hybrid type is provided with a case part 3 and an operation device 10, which allows the gas generated by burning the gas generating agent filled into a housing 11 to flow out into the case part 3 at operation time, boost internal pressure in the case part 3 to break a rupture plate in the case part 3, and discharge the gas for inflation through a gas discharge port. The housing 11 is constituted to extend an inner peripheral face 11a from an end part on a flow-out hole 17 side in a squib storage part 15 to a section in the vicinity of an inner peripheral fringe on a tip side where the flow-out hole 17 is arranged linearly. The gas generating agent is filled into the housing 11 by a filling factor in a scope of 75-90% to the capacity of the housing 11. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a hybrid-type inflator having a configuration in which an expansion gas flows out from a gas discharge port by increasing an internal pressure of a pressurized gas filled therein during operation of an actuator.

  Conventionally, a hybrid type inflator has an operating device disposed in a case portion filled with a pressurized gas, a housing filled with a gas generating agent that generates gas during combustion, and a flame during operation. A squib capable of igniting the gas generating agent, and when operating the operating device, the gas generated by burning the gas generating agent is caused to flow into the case portion, thereby increasing the internal pressure in the case portion. It was the structure which bursts the rupture disk which obstruct | occludes a gas discharge port and discharges the gas for expansion from a gas discharge port.

  In this type of inflator, the gas generated by operating the squib is caused to flow into the case part, the internal pressure of the case part is increased, and the rupturable plate is ruptured. A certain amount of time is required until the start of the inflation gas discharge from the discharge port, but in order to make the inflator performance substantially constant, the time required from the start of the squib operation to the start of the inflation gas discharge is suppressed. Therefore, it is desired to make it substantially constant.

And as a small gas generator similar to this inflator operating device, there is one in which the filling rate of the gas generating agent is set within a range of 80 to 90% with respect to the volume of the housing (for example, Patent Documents). 1).
JP 2001-88653 A

  However, although the gas generator described in Patent Document 1 sets the filling rate of the gas generating agent within the range of 80 to 90%, the housing is disposed on the inner peripheral surface side of the squib side with the squib and the gas. Since it is configured to include a partition portion that partially protrudes so as to partition the generating agent, it is difficult to ignite the gas generating agent that is filled in the vicinity of the partition portion when the squib is operated, and this portion is filled Unburnt occurred in the gas generating agent, and the time taken from the start of squib operation to the start of gas discharge varied.

  The present invention solves the above-described problems, and an object thereof is to provide an inflator capable of making the time taken from the start of the operation of the squib to the start of discharge of the inflation gas substantially constant while suppressing variations. To do.

The inflator according to the present invention is filled with a pressurized gas for generating an expansion gas inside, and a case portion including a gas discharge port closed by a rupturable plate,
An actuating device disposed in the case portion and capable of rupturing the rupturable plate during operation and discharging the pressurized gas filled in the case portion from the gas discharge port;
It is set as the composition provided with,
An operating device includes a housing filled with a gas generating agent that generates a gas during combustion, and a squib housed in the housing and capable of igniting the gas generating agent.
The housing has a squib storage part for storing the squib on the base part side, and is communicated with the inside of the case part at the tip side away from the squib storage part and facing the squib, and is generated when the gas generating agent burns. It is configured to have an outflow hole that allows gas to flow out into the case part,
When operating the actuator, the gas generated by burning the gas generating agent is discharged into the case part, thereby increasing the internal pressure in the case part to rupture the rupturable plate and discharging the inflation gas from the gas outlet Hybrid type inflator
The housing is configured to extend linearly from the end on the outflow hole side in the squib storage part to the vicinity of the inner peripheral edge on the tip side where the outflow hole is disposed,
The gas generating agent is filled in the housing at a filling rate in the range of 75 to 90% with respect to the volume of the housing.

  In the inflator of the present invention, the inner peripheral surface from the end filled with the gas generating agent to the vicinity of the inner peripheral edge on the front end side where the outflow hole is disposed, from the end on the outflow hole side in the squib storage portion, Since it is configured to extend in a straight line, when the squib is operated, the flame at the time of ignition is evenly applied to the gas generating agent in the area located near the end on the outflow hole side in the squib storage part without any gap. This makes it easier to ignite the entire gas generating agent in the area. As a result, it is possible to prevent unburned residue from being generated in the gas generating agent in the area located near the end on the outflow hole side in the squib storage part. In the inflator of the present invention, since the gas generating agent is filled in the housing at a filling rate in the range of 75 to 90% with respect to the volume of the housing, the gap in the housing is reduced. Thus, the flame from the squib can be smoothly and quickly propagated throughout the gas generating agent, and variations in the combustion completion time of the gas generating agent can be suppressed.

  Therefore, in the inflator of the present invention, during the operation of the squib, the entire gas generating agent can be quickly burned, and the time taken from the start of the squib operation to the start of gas outflow into the case part is suppressed, It can be made substantially constant. As a result, in the inflator of the present invention, the burst timing of the rupturable plate can be made substantially constant, and the discharge start time of the expansion gas from the gas discharge port can be made substantially constant.

  Therefore, in the inflator of the present invention, the time taken from the start of the operation of the squib to the start of discharge of the inflation gas can be made substantially constant while suppressing variations.

  Further, in the inflator of the present invention, the gas generating agent filled in the housing can be burned smoothly and quickly while suppressing the occurrence of unburned residue, so that the expansion gas discharge start time can be reduced. At the same time, the amount of inflation gas discharged from the gas discharge port can be substantially constant. Therefore, the tank curve during the tank combustion test can be made substantially constant, and stable performance can be secured as an inflator.

  Further, in the inflator according to the present invention, the inner peripheral surface of the housing is configured to be inclined so as to expand from the end portion on the outflow hole side in the squib storage portion to the distal end side where the outflow hole is disposed, If the corner portion on the outflow hole side in the peripheral surface is curved and narrowed, and it is configured so as to be continuous with the inner peripheral edge of the outflow hole, the inner peripheral surface of the housing is inclined so as to expand toward the tip side. Even in this case, the corner part is curved and does not form narrow sharp corners, so the gas generated by burning the gas generant is located on the tip side away from the squib in the housing (near the outflow hole) This is preferable because it can be prevented from staying at the part) and the generated gas can smoothly flow out from the outflow hole to the case part side.

  Furthermore, in the inflator according to the present invention, the inner peripheral surface of the housing may be tapered from the squib storage part so as to be tapered from the end part on the outflow hole side of the squib storage part to the tip side where the outflow hole is provided. The inclined surface that is inclined toward the hole may be configured to be continuous with the inner peripheral edge of the outflow hole. In such a configuration, the gas generated by the combustion of the gas generating agent stays in the entire area inside the housing. It is possible to prevent the generated gas from flowing out from the outflow hole to the case portion side, which is preferable.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. As shown in FIG. 1, the inflator 1 of the embodiment is a substantially cylindrical cylinder type, and a diffuser 22 that can flow inflation gas into an airbag (not shown) on the side of a gas discharge port 5 to be described later. Are used together. In the case of the embodiment, the inflator 1 has a configuration in which a base portion 4 having a gas discharge port 5 is disposed on one end side of a substantially cylindrical case portion 3 and an operating device 10 is disposed on the other end side. It is said that.

  The case part 3 is formed from a steel metal pipe. The case part 3 is formed in a substantially cylindrical shape having both ends in the axial direction opened, and both ends along the axial direction are respectively formed by the base part 4 and the operating device 10. It is closed, and the inside is filled with a pressurized gas composed of nitrogen gas, helium gas, argon gas, or a mixed gas thereof.

  The base portion 4 is formed of a metal material such as steel, and is disposed so as to close one end side of the case portion 3, and the periphery on the base portion 4 a side is welded and fixed to the case portion 3. In addition, a plurality of gas discharge ports 5 are provided on the tip 4b side. In the case of the embodiment, the base portion 4 has a portion on the tip 4b side having a smaller diameter than the portion on the base portion 4a side, and the gas discharge port 5 on the tip 4b side in the direction around the axis of the substantially cylindrical outer peripheral surface. It is set as the structure arrange | positioned many over the whole area along. Further, in the embodiment, the diffuser 22 is applied to the inflator 1 by caulking the base part side to the concave groove part 6 formed over the entire region along the axis around the base part 4a side of the base part 4. It is the structure connected.

  Further, a rupturable plate 7 is disposed on the base portion 4a side of the base portion 4 so as to partition the base portion 4 and the case portion 3 and close the gas discharge port 5 (see FIG. 1). In the rupturable plate 7, a gas generated by burning a gas generating agent 19 filled in the housing 11 is discharged into the case portion 3 by a flame generated by igniting a squib 20 (to be described later) of the actuator 10. When the internal pressure in the case part 3 rises, the case part 3 bursts, the base part 4 communicates with the case part 3, and the inflation gas is discharged from the gas discharge port 5.

  As shown in FIGS. 2 and 3, the operating device 10 includes a housing 11 filled with a gas generating agent 19 that generates gas during combustion, and a squib that is housed in the housing 11 and can ignite the gas generating agent 19. 20.

  The squib 20 is stored so that the tip end side is inserted into the squib storage part 15 disposed on the base part side away from the case part 3 in the housing 11 and the base part side is exposed to the outside of the squib storage part 15. Therefore, the base side is connected to a lead wire (not shown). As shown in FIG. 2, the squib 20 has a substantially disc-shaped flange portion 20a on the front end side, and a substantially cylindrical shape that is configured to have a smaller diameter than the flange portion 20a and project from the flange portion 20a to the front end side. When the inflator 1 is mounted on a vehicle as an airbag device, the head 20b is electrically connected to the vehicle control device via the lead wire. In response to the operation signal from the head 20b, the head 20b is operated to generate a flame, and the gas generating agent 19 is combusted.

  In the case of the embodiment, the housing 11 is formed of a metal material such as steel, and is disposed so as to close the other end side of the case portion 3. The housing 11 has a substantially cylindrical shape, and includes a cylindrical peripheral wall portion 12 and an end side wall portion 13 that closes the distal end side of the peripheral wall portion 12, and the periphery of the end side wall portion 13 is welded. And fixed to the case portion 3. The housing 11 is disposed on the base portion side away from the case portion 3 and accommodates the squib housing portion 15 for housing the squib, and is disposed on the distal end side on the case portion 3 side for housing the gas generating agent. And a generating agent storage unit 16. The generating agent storage portion 16 and the case portion 3 communicate with each other at the front end side of the generating agent storage portion 16 and at the center of the end side wall portion 13 that faces the squib 20 to burn the gas generating agent 19. An outflow hole 17 through which gas generated at times can flow out into the case portion 3 is formed. And in the case of embodiment, the surrounding wall part 12 is comprised so that thickness dimension may be made constant from the base part side which comprises the squib accommodating part 15 to the front end side which comprises the generating agent accommodating part 16. FIG. . That is, the housing 11 of the embodiment has an end on the outflow hole 17 side (front end side) in the squib storage portion 15 so that the inner peripheral surface 16a from the base side to the front end side in the generating agent storage portion 16 is linear. The inner peripheral surface 11 a from the portion 15 a to the vicinity of the inner peripheral edge of the end side wall portion 13 on the distal end side where the outflow hole 17 is disposed is configured to extend linearly in parallel with the axial direction of the housing 11. ing. Specifically, the inner peripheral surface 11a of the housing 11 extends linearly from at least a portion in the diameter direction of the inner peripheral surface 11a of the housing 11 corresponding to the end surface of the flange portion 20a of the squib 20 on the head 20b side. It is configured.

  Although omitted in FIGS. 1 and 2, the gas generating agent 19 having the shape shown in FIG. 3 is filled in the generating agent storage 16 in the housing 11. As shown in FIG. 3, the gas generating agent 19 used in the inflator 1 of the embodiment has a substantially cylindrical shape having a hollow portion 19a. In the case of the embodiment, the gas generating agent 19 has a filling rate in the range of 75 to 90% (preferably 80 to 90%) with respect to the volume of the housing 11, and the inside of the generating agent storage section 16 in the housing 11. Is filled. When the filling rate of the gas generating agent 19 is less than 75%, there are more voids in the generating agent storage portion 16, so that the flame from the squib 20 is smoothly propagated throughout the gas generating agent 19 when the squib 20 is ignited. On the other hand, if the filling rate exceeds 90%, the filling amount of the gas generating agent 19 is excessive, and the housing 11 may be destroyed when the squib 20 is ignited. FIG. 4 shows a graph showing the correlation between the filling rate of the gas generating agent 19 and the time difference from the start of operation of the squib 20 to the start of gas discharge. The larger the filling rate of the gas generating agent 19, the more the squib 20 The time difference from the start of the operation to the start of gas discharge from which the inflation gas is actually discharged from the inflator 1 is reduced, and the variation in the time difference is also reduced. And since it is desirable that the time difference from the start of operation of the squib 20 to the start of gas discharge from which the inflation gas is discharged from the inflator 1 is less than 3.5 msec, in the embodiment, the filling rate of the gas generating agent 19 Is 75% or more. The gas generating agent 19 is set to a size that does not enter the gap between the flange portion 20 a of the squib 20 and the inner peripheral surface 11 a of the housing 11. And in the case of embodiment, the gas generating agent 19 shall be a magnitude | size which is not filled between the outer peripheral surface of the head 20b in the squib 20, and the inner peripheral surface 11a of the housing 11 located in the diameter direction. Is preferred.

  In the inflator 1 according to the embodiment, when an operation signal is input to the squib 20 of the operating device 10 via a lead wire (not shown) in a state where the air bag device is mounted on a vehicle, the squib 20 is ignited and the housing 11 The gas generating agent 19 filled in the generating agent storage portion 16 is burned to generate gas. Then, the gas generated by the combustion of the gas generating agent 19 flows into the case portion 3 through the outflow hole 17, raises the internal pressure in the case portion 3, ruptures the rupturable plate 7, and the gas generating agent 19. The gas generated by combustion of the gas and the pressurized gas filled in the case portion 3 are discharged from the gas discharge port of the base portion 4 as the expansion gas.

  In the inflator 1 of the embodiment, the substantially cylindrical peripheral wall portion 12 of the housing 11 filled with the gas generating agent 19 has a constant thickness dimension, and the housing 11 has an outflow hole in the squib storage portion 15. The inner peripheral surface 11a (the inner peripheral surface 16a of the generating agent storage portion 16) from the end portion 15a on the 17 side to the vicinity of the inner peripheral edge of the end side wall portion 13 on the distal end side where the outflow hole 17 is disposed, It is comprised so that it may extend linearly. Therefore, when the squib 20 is operated, it is easy to apply the flame at the time of ignition to the gas generating agent 19 in the area located near the end 15a on the outflow hole 17 side in the squib storage part 15 without any gap. The entire gas generating agent 19 can be ignited. As a result, it is possible to prevent unburned residue from being generated in the gas generating agent 19 in the area located near the end 15a on the outflow hole 17 side in the squib storage part 15. Further, in the inflator 1 of the embodiment, the gas generating agent 19 is filled in the housing 11 at a filling rate in the range of 75 to 90% with respect to the volume of the housing 11. The gap in the agent storage portion 16) can be reduced, the flame from the squib 20 can be propagated smoothly and quickly to the entire gas generating agent 19, and the combustion completion time of the gas generating agent 19 varies. Can be suppressed.

  Therefore, in the inflator 1 of the embodiment, when the squib 20 is operated, the entire gas generating agent 19 can be burned quickly, and the time required from the start of the operation of the squib 20 to the start of gas outflow into the case portion 3 is reduced. Can be made substantially constant. As a result, in the inflator 1 of the embodiment, the burst timing of the rupturable plate 7 can be made substantially constant, and the discharge start time of the inflation gas from the gas discharge port 5 can also be made substantially constant.

  Therefore, in the inflator 1 of the embodiment, the time taken from the start of operation of the squib 20 to the start of discharge of the inflation gas can be made substantially constant while suppressing variations.

  In addition, in the inflator 1 of the embodiment, the gas generating agent 19 filled in the housing 11 can be burned smoothly and quickly while suppressing the occurrence of unburned gas, so that the gas for expansion is discharged. The start time can be made substantially constant, and at the same time, the amount of the inflation gas discharged from the gas discharge port 5 becomes substantially constant. Therefore, the tank curve during the tank combustion test can be made substantially constant, and stable performance can be secured as an inflator.

  Incidentally, the tank curve is data obtained during a tank combustion test, and the tank combustion test is a test performed in the following procedure. An inflator is fixed in a stainless steel tank having an internal volume of 60 liters, and after sealing the tank at room temperature, the inflator is connected to an external ignition electric circuit. Then, the pressure transducer installed in the tank is set to 0 (ignition current application) time when the ignition electric circuit switch is turned on, and the change in pressure in the tank is measured for 0 to 200 msec. A tank curve for evaluating the performance of the inflator can be obtained by using each measurement data as a result of the test as a tank pressure / time curve finally by computer processing.

  Further, as shown in FIG. 5, the actuating device 10 </ b> A has an inner peripheral surface 16 b of the generating agent storage portion 16 </ b> A in the housing 11 </ b> A, and an end portion 15 a on the outflow hole 17 </ b> A side in the squib storage portion 15 </ b> A From the diametrical portion of the inner peripheral surface 11a of the housing 11 corresponding to the end surface on the head 20b side) to the distal end side where the outflow hole 17A is disposed, it is configured to be inclined so as to expand linearly, You may comprise so that the corner part 16e by the side of the outflow hole 17A in the internal peripheral surface 16a may be curved and narrowed, and it may continue to the inner periphery of the outflow hole 17A. In the operating device 10A having such a configuration, even if the inner peripheral surface 16b of the generating agent storage portion 16A in the housing 11A is inclined so as to expand toward the tip 16d side, the corner portion 16e is curved. Since a narrow acute corner is not formed, a gas generated by burning a gas generating agent (not shown) is generated in a portion (side on the outflow hole 17A) on the tip 16d side away from the squib 20 in the housing 11A. This is preferable because it can be prevented from staying and the generated gas can smoothly flow out from the outflow hole 17A to the case portion side.

  Further, as shown in FIG. 6, the actuating device 10 </ b> B has an inner peripheral surface 16 f of the generating agent storage portion 16 </ b> B in the housing 11 </ b> B and an end 15 a on the outflow hole 17 </ b> B side in the squib storage portion 15 </ b> B. The squib storage portion is linearly and tapered from the diametrical portion of the inner peripheral surface 11a of the housing 11 corresponding to the end surface on the head 20b side to the distal end side where the outflow hole 17B is disposed. You may comprise as an inclined surface which inclines from 15B to the outflow hole 17B. In the operating device 10B having such a configuration, the gas generated by the combustion of the gas generating agent (not shown) can be prevented from staying over the entire area inside the housing 11B (generating agent storage portion 16B). It is preferable because it can quickly flow out from 17B to the case portion side.

It is a schematic sectional drawing of the inflator which is one Embodiment of this invention. It is a partial expanded sectional view which shows the site | part vicinity of the actuator in the inflator of FIG. It is a perspective view of the gas generating agent used with the inflator of FIG. In the inflator of embodiment, it is a graph which shows the correlation with the filling rate of a gas generating agent, and the time difference from the operation start of a squib to the gas discharge start. It is a partial expanded sectional view which shows the site | part vicinity of the actuator which is other embodiment of this invention. It is a partial expanded sectional view which shows the site | part vicinity of the actuator which is further another embodiment of this invention.

Explanation of symbols

1 ... Inflator,
3 ... case part
5 ... Gas outlet,
7 ... Rupture disc,
10, 10A, 10B ... Actuator,
11, 11A, 11B ... housing,
15, 15A, 15B ... squib storage part,
16, 16A, 16B ... generating agent storage part,
16a, 16b, 16f ... inner peripheral surface,
17, 17A, 17B ... outflow hole,
19 ... gas generating agent,
20 ... Squib.

Claims (3)

A case portion having a gas discharge port closed by a rupturable plate while being filled with a pressurized gas for generating an expansion gas inside,
An actuating device disposed in the case part and capable of rupturing the rupturable plate during operation and discharging the pressurized gas filled in the case part from a gas outlet;
It is set as the composition provided with,
The operating device includes a housing filled with a gas generating agent that generates gas at the time of combustion, and a squib housed in the housing and capable of igniting the gas generating agent.
The housing includes a squib storage part for storing the squib on the base side, and communicates with the inside of the case part at a front end side away from the squib storage part and facing the squib. An outflow hole through which gas generated during combustion of the generating agent can flow out into the case portion is disposed,
During operation of the operating device, the gas generated by burning the gas generating agent is caused to flow into the case portion, thereby increasing the internal pressure in the case portion to rupture the rupturable plate and expand from the gas discharge port. A hybrid type inflator configured to discharge a working gas,
The housing is configured to extend linearly from the end on the outflow hole side in the squib storage part to the vicinity of the inner peripheral edge on the tip side where the outflow hole is disposed,
The inflator is characterized in that the gas generating agent is filled in the housing at a filling rate within a range of 75 to 90% with respect to the volume of the housing.   The inner peripheral surface of the housing is configured to be inclined so as to expand from an end portion on the outflow hole side in the squib storage portion to a distal end side on which the outflow hole is disposed, and the inner peripheral surface 2. The inflator according to claim 1, wherein the inflator is configured so as to be continuous with an inner peripheral edge of the outflow hole while curving and narrowing a corner portion on the outflow hole side.   The inner peripheral surface of the housing is inclined from the squib storage part to the outflow hole so as to taper from an end part on the outflow hole side of the squib storage part to a tip side where the outflow hole is provided. The inflator according to claim 1, wherein the inflator is configured as an inclined surface so as to be continuous with an inner peripheral edge of the outflow hole.

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