JP2008213527A - Inflator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inflator capable of suppressing a mass flow rate at the initial stage of working, and keeping the mass flow rate equal to or more than a predetermined value for a long time. <P>SOLUTION: An inflator 10 contains a pressurized gas for inflation G supplied to an airbag 1. In working, the inflator 10 breaks a rupture disk 23 for blocking an exhaust port 22 so as to exhaust the pressurized gas G from the exhaust port 22. At a portion of the exhaust port 22, a flow rate adjusting mechanism 33 capable of adjusting the flow rate of the pressurized gas G exhausted from the exhaust port 22 is arranged. The flow rate adjusting mechanism 33 openably and closably blocks a needle 42 capable of breaking the rupture disk 23 by abutting its tip end in the moving side to the rupture disk 23, and the exhaust port 22 opened by the needle 42. Further, the inflator 10 is equipped with a valve body 43 having an outlet 44 capable of supplying the pressurized gas G to an airbag 1 side in blocking the exhaust port 22 as an opening area smaller than the opening area of the exhaust port 22, and a drive mechanism 34 capable of moving the needle 42 and the valve body 43. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an inflator used in an airbag device mounted on a vehicle or the like, and more specifically, operates by storing a pressurized gas (cold gas) for inflating an airbag of the airbag device inside. Sometimes, it relates to a stored type inflator that discharges the pressurized gas.

  Conventionally, as this type of stored type inflator, a pressurized gas for inflation supplied to an airbag is built in, and during operation, the bursting plate that has closed the discharge port is broken, and the pressurized gas is discharged from the discharge port. It was discharged (for example, refer to Patent Document 1). In this inflator, an initiator (squib or igniter) that generates a small amount of combustion gas when energized is placed in the vicinity of the rupture plate. When activated, the initiator is ignited and the rupture plate is ruptured by the pressure of the generated fuel gas. As a result, the discharge port was opened and the pressurized gas was discharged.

There is also a hybrid type inflator that is not a stored type but inflates an airbag by using a pressurized gas and a combustion gas in combination (for example, see Patent Documents 2 and 3).
JP 2002-120687 A JP-T-2004-503423 JP 2002-120687 A

  However, in the conventional stored type inflator, when the bursting plate is ruptured and the discharge port is opened, the pressurized gas stored in the pressurized state suddenly increases the mass flow rate. Then, it was discharged in a state where the mass flow rate was rapidly reduced by the outflow of the pressurized gas in the inflator.

  Therefore, an airbag that is inflated by being supplied with pressurized gas from an inflator suddenly raises the internal pressure to complete the inflation, and then reduces the internal pressure as the mass flow rate of the pressurized gas supplied from the inflator decreases. It was decreasing rapidly. That is, in the conventional stored type inflator, the suppression of the mass flow rate for suppressing the internal pressure of the airbag immediately after the operation, and the suppression of the decrease in the mass flow rate for extending the time for maintaining the internal pressure of the airbag over a predetermined value, There was a problem.

  Moreover, the hybrid type inflator described in Patent Documents 2 and 3 adjusts the mass flow rate of the gas for inflation into the airbag in a state where the opening area of the discharge port can be increased or decreased. However, in these inflators, the combustion gas is used and the initiator is used to rupture the rupturable plate for opening the discharge port. Therefore, the initial mass flow rate of the inflator is the opening area of the discharge port. Even if it is controlled to be small, there is a room for improvement in that the mass flow rate at the beginning of operation is suppressed because it suddenly increases.

  The present invention solves the above-described problems, and an object of the present invention is to provide an inflator that can suppress a mass flow rate at the beginning of operation and can maintain a mass flow rate equal to or higher than a predetermined value for a long time.

An inflator according to the present invention is an inflator that incorporates pressurized inflation gas to be supplied to an airbag, breaks a rupturable plate that has closed the discharge port, and discharges pressurized gas from the discharge port during operation. And
A flow rate adjusting mechanism capable of adjusting the flow rate of the pressurized gas discharged from the discharge port is disposed at the site of the discharge port,
The flow adjustment mechanism
Apply the tip of the moving side to the rupturable plate, a needle that can break the rupturable plate,
A valve provided with an outlet that closes the discharge port opened by the needle so that it can be opened and closed, and has an opening area smaller than the opening area of the discharge port, and can supply pressurized gas to the airbag side when the discharge port is closed Body,
A drive mechanism for moving the needle and the valve body;
It is characterized by comprising.

  In the inflator according to the present invention, during operation, the drive mechanism moves the needle and the valve body, so that the needle hits the rupturable plate and breaks the rupturable plate, and at the same time, the valve body closes the discharge port. Therefore, the pressurized gas flows out to the airbag side through the outlet of the valve body. At that time, since the outlet has an opening area smaller than the opening area of the discharge port opened by breaking the rupturable plate, the pressurized gas flows out from the inflator as a smaller mass flow rate than when the discharge port is fully opened. After that, if the drive mechanism moves the valve body and opens the discharge port according to the timing when the mass flow rate starts to decrease, the discharge port with a larger opening area than the outflow port opens. Thus, the pressurized gas is easy to be discharged, the decrease in the mass flow rate is suppressed, and the pressurized gas is discharged from the inflator.

  Therefore, in the inflator according to the present invention, the initial mass flow rate can be suppressed, and a mass flow rate equal to or higher than a predetermined value can be maintained for a long time. The airbag inflated by the inflator according to the present invention can suppress a sudden increase in internal pressure at the beginning of the operation of the inflator, can prevent damage, and restrains a driver or an occupant such as a driver during the inflation. Even if it becomes, it can restrain with a sufficient cushioning property, suppressing the reaction force given to the prospective restraint person. In addition, the airbag inflated by the inflator according to the present invention can suppress a decrease in internal pressure after completion of inflation, and can secure a predetermined internal pressure and restrain it with good cushioning properties even if a person scheduled to be restrained enters later. Become.

  The needle and the valve body are preferably formed integrally and held by the drive mechanism so as to be movable along a direction orthogonal to the opening surface of the discharge port. In such a configuration, the drive mechanism only needs to drive one component in which the needle and the valve body are integrated, and the configuration can be simplified.

  In this case, if the inflator is configured by providing a tank chamber with a discharge port and containing pressurized gas, the flow rate adjusting mechanism is arranged outside the tank chamber rather than being arranged inside the tank chamber. It is desirable to install. That is, if the flow rate adjusting mechanism is provided outside the tank chamber, the tank chamber can be provided without penetrating the signal line and the like for inputting the drive signal of the drive mechanism in the flow rate adjusting mechanism into and out of the tank chamber. It can be easily done only outside.

  In addition, if the drive mechanism is configured from an electromagnetic solenoid, it can be easily configured including management as compared with the case where explosives such as a micro gas generator are used. When an electromagnetic solenoid is used as a drive mechanism, it is inferior in that the needle and the valve body are driven quickly compared to a micro gas generator, but it is not possible to avoid a vehicle collision before the actual vehicle collision. If it is configured to be operated from the time when it is determined, that is, from the time of collision prediction (collision prediction), the airbag is loosened compared to the conventional airbag device that inflates the airbag from the time of the actual collision. Even if the person who is scheduled to hit the airbag in the middle of inflation can be inflated, the person who is scheduled to restrain can be suitably received by the airbag while suppressing the reaction force.

  When an inflator is configured by providing a tank chamber with a discharge port and containing pressurized gas, an initiator capable of increasing the pressure in the tank chamber to break the rupturable plate is disposed in the tank chamber. You may keep it. In such a configuration, as described above, the normal operation of the inflator was configured to operate from the time of collision prediction when it was determined that the vehicle collision in the previous stage of the actual vehicle collision could not be avoided. In some cases, it can be suitably used. Because, without predicting the collision of the vehicle, if there is a sudden collision of the actual vehicle, the initiator is activated, and the pressurized gas is discharged from the discharge port with the opening fully opened from the beginning of the operation of the inflator. This is because the airbag can be quickly inflated, and the person who is scheduled to restrain can be suitably received by the airbag that has been inflated.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. As shown in FIGS. 1 to 3, the inflator 10 of the first embodiment has a substantially cylindrical outer case 31 around a columnar body 11. Is configured to cover. A cylindrical gas inlet 2 of the airbag 1 is connected to an end of the outer case 31 away from the discharge port 22 of the main body 11 using a clamp (not shown). In the case of the embodiment, the airbag 1 is used in a head protection airbag device that covers a window of a vehicle.

  The outer case 31 is formed of a metal pipe, and is joined by caulking the outer peripheral surfaces of the flange portion 29 on the discharge port 22 side of the main body 11 and the flange portion 16 on the other end side so as to be plastically deformed. The pressurized gas G discharged from the discharge port 22 passes through the opening 27, the cylindrical space S between the peripheral wall portion 13 of the main body 11 and the inner peripheral surface of the outer case 31, and the communication hole 17. It is arranged so as to flow into the airbag 1.

  The main body 11 includes a tank chamber 12 containing a pressurized gas (cold gas) G made of an inert gas such as nitrogen gas, and a flow rate adjusting mechanism 33 disposed near the discharge port 22 outside the tank chamber 12. And is configured. The tank chamber 12 includes a cylindrical peripheral wall portion 13 made of a metal pipe, a bottom wall portion 14 that closes one end of the peripheral wall portion 13 on the side of the airbag 1 away from the discharge port 22, and a discharge at the peripheral wall portion 13. And a discharge side wall portion 20 disposed so as to close the end portion on the outlet 22 side. The bottom wall portion 14 and the discharge side wall portion 20 are formed from a metal block using a press process, a cutting process, or the like, and are welded and joined to the peripheral wall portion 13.

  The discharge side wall portion 20 includes a disk-shaped blocking wall portion 21 having a discharge port 22 that opens in a circular shape at the center, and is separated from the airbag 1 outside the tank chamber 12 from the outer peripheral edge of the blocking wall portion 21. And a flange portion 29 extending in a hook shape in the direction orthogonal to the axis of the main body 11 from the tip of the communication wall portion 26. A portion surrounded by the blocking wall portion 21 and the communication wall portion 26 constitutes a housing portion 25 that houses the flow rate adjusting mechanism 33. A rupturable plate 23 is fixed to the periphery of the discharge port 22 of the blocking wall 21 inside the tank chamber 12 to close the discharge port 22. The rupturable plate 23 is configured to be broken when the needle 42 moves so as to enter the tank chamber 12 and when the internal pressure rises in the tank chamber 12 due to generation of combustion gas when the initiator 18 is activated. In addition to this, the discharge port 22 is closed so that the pressurized gas G stored in the tank chamber 12 is not discharged. In addition, a plurality of openings 27 penetrating inward and outward are formed in the cylindrical communication wall portion 26.

  The bottom wall portion 14 is provided with a storage portion 15 in which an initiator 18 is disposed on the inner side of the tank chamber 12, and a flange-like flange portion 16 that extends in the direction perpendicular to the axis of the main body 11 is projected. . A plurality of communication holes 17 penetrating along the axial direction of the main body 11 are opened in the flange portion 16. The initiator 18 is arranged to rupture the rupturable plate 23 by generating a small amount of combustion gas when energized and increasing the internal pressure in the tank chamber 12.

  The flow rate adjusting mechanism 33 adjusts the flow rate of the pressurized gas G discharged from the discharge port 22, and an operating piece 41 in which the needle 42 and the valve body 43 are integrated, and a drive for driving the operating piece 41. And a mechanism 34. The drive mechanism 34 includes a coil 36, a fixed iron core 37, and a movable iron core 38. When the coil 36 is energized, the drive mechanism 34 moves so that the movable iron core 38 is attracted to the fixed iron core 37 located on the airbag 1 side. A solenoid 35 is used. A member 39 is a spring for returning the movable iron core 38 to the position before the operation together with the needle 42 and the valve body 43 when the energization to the electromagnetic solenoid 35 is stopped.

  The operating piece 41 is held by the movable iron core 38 and moves along a direction orthogonal to the opening surface of the discharge port 22. The operation piece 41 includes a disc-shaped valve body 43 and a needle 42 that protrudes from the center of the valve body 43 in a rod shape toward the discharge port 22. The disc-shaped valve body 43 has an outer diameter dimension larger than the inner diameter dimension of the discharge port 22 and abuts the periphery of the discharge port 22 outside the tank chamber 12 of the blocking wall portion 21 when the electromagnetic solenoid 35 is operated. The discharge port 22 can be closed, and is further provided with a plurality of outlets 44 through which the pressurized gas G in the tank chamber 12 flows into the housing portion 25 when the discharge port 22 is closed. The total opening area of the plurality of outlets 44 is smaller than the opening area of the discharge port 22. The needle 42 hits the rupturable plate 23 when the electromagnetic solenoid 35 is operated, and is further disposed so as to break the rupturable plate 23 and enter the tank chamber 12.

  The inflator 10 is controlled by a control device (not shown). The control is energized to the electromagnetic solenoid 35 of the drive mechanism 34 when it is predicted that a side collision of the vehicle cannot be avoided. Control is performed such that energization is stopped when the mass flow rate decreases rapidly after ˜300 ms. That is, when it is predicted that a vehicle collision cannot be avoided, a control device (not shown) inputs a signal of a predetermined collision prediction sensor to operate the electromagnetic solenoid 35, and after a predetermined time has passed, Turn off the power. Note that the time from when the electromagnetic solenoid 35 is energized to when the energization is stopped is determined by measuring the timing at which the mass flow rate rapidly decreases after the operation of the inflator 10 by a tank test or the like, and setting it according to the timing.

  Further, the control device (not shown) is configured to input a signal from a collision detection sensor that can detect an actual vehicle collision, and the control device does not input a signal from the collision prediction sensor. When the actual collision of the vehicle is suddenly detected based on the signal from the, the energization is performed so that the initiator 18 is operated without energizing the electromagnetic solenoid 35.

  In the inflator 10 of the first embodiment, during normal operation, as shown in FIGS. 3A and 3B, the electromagnetic solenoid 35 of the drive mechanism 34 moves the movable iron core 38 so that the needle 42 and the valve body 43 are moved. Are moved together. Then, the needle 42 hits the rupturable plate 23 and breaks the rupturable plate 23, and at the same time, the valve body 43 closes the discharge port 22. Therefore, the pressurized gas G flows into the accommodating portion 25 through the outlet 44 of the valve body 43, and flows into the space S between the main body 11 and the outer case 31 through the opening 27 from the accommodating portion 25 (see FIG. 2), and further flows out through the communication hole 17 to the airbag 1 side. In that case, since the outflow port 44 has an opening area smaller than the opening area of the discharge port 22 that is opened when the rupturable plate 23 is broken, the pressurized gas G is used as an inflator as a smaller mass flow rate than when the discharge port 22 is fully opened. 10 flows out to the airbag 1 side (see the solid line in FIG. 4). Thereafter, if the energization to the electromagnetic solenoid 35 of the drive mechanism 34 is stopped in accordance with the timing when the mass flow rate starts to decrease, the valve element 43 moves away from the discharge port 22 as shown in FIGS. Since the discharge port 22 is opened and the discharge port 22 having a wider opening area than the outflow port 44 is opened, the built-in pressurized gas G can be easily discharged, and the decrease in the mass flow rate is suppressed. The gas G is discharged from the inflator 10.

  Therefore, in the inflator 10 of 1st Embodiment, the mass flow rate at the time of an operation | movement can be suppressed, and the mass flow rate beyond a predetermined value can be maintained long. The airbag 1 inflated by the inflator 10 according to the first embodiment can suppress a sudden increase in internal pressure at the beginning of the operation of the inflator 10, can prevent damage, and can be restrained by a driver, an occupant, or the like during the inflation. Even if it is restrained, it is possible to restrain the reaction force applied to the person scheduled to be restrained with good cushioning properties. Further, the airbag 1 inflated by the inflator 10 of the first embodiment can suppress a decrease in internal pressure after completion of inflation, and the vehicle 1 rolls over so that the vehicle rolls over and the person who is scheduled to restrain enters the airbag 1 with a delay. However, a predetermined internal pressure can be ensured and restrained with good cushioning properties.

  4 is a graph showing a mass throw rate of a conventional stored type inflator, and the operation timing of the inflator is activated when a vehicle collision is detected. As can be seen from this graph, in the inflator 10 of the first embodiment, the mass flow rate at the beginning of operation can be suppressed, and the mass flow rate after the operation can be averaged, and the operation is performed from the time of vehicle collision prediction. Thus, the airbag 1 can be suitably used for an airbag device that is inflated while suppressing a sudden increase in internal pressure, and wants to extend the time during which the internal pressure value of the airbag 1 can be maintained at a predetermined level or higher.

  In the case of the embodiment, the needle 42 and the valve body 43 are configured by an integrally formed operating piece 41 and are movable along a direction orthogonal to the opening surface of the discharge port 22. Is held by a movable iron core 38 of an electromagnetic solenoid 35 constituting the. Therefore, in such a configuration, the drive mechanism 34 need only drive the one-piece operation piece 41 in which the needle 42 and the valve body 43 are integrated, and can be simply configured.

  Furthermore, in the first embodiment, the inflator 10 is configured by including the tank chamber 12 provided with the discharge port 22 and containing the pressurized gas G, and the flow rate adjusting mechanism 33 is disposed outside the tank chamber 12. ing. Therefore, compared with the case where the flow rate adjusting mechanism 33 is provided inside the tank chamber 12, the signal line for inputting the drive signal of the drive mechanism 34 in the flow rate adjusting mechanism 33 is penetrated inside and outside the tank chamber 12. This can be easily performed only outside the tank chamber 12. Of course, if this point is not taken into consideration, the flow rate adjusting mechanism 33 may be disposed inside the tank chamber 12.

  Furthermore, in the first embodiment, the drive mechanism 34 is configured by an electromagnetic solenoid 35, and can be easily configured including management as compared with the case where explosives such as a micro gas generator are used. When the electromagnetic solenoid 35 is used for the drive mechanism 34, it is inferior to the micro gas generator in that the needle 42 and the valve body 43 are driven quickly, but the actual collision of the vehicle as in the embodiment. Compared to the conventional airbag device that inflates the airbag from the time of the actual collision, if it is configured to operate from the time when it is determined that the collision of the vehicle in the previous stage cannot be avoided, that is, from the time of the collision prediction, The airbag 1 can be gently inflated, and even if a person who is to be restrained hits the airbag 1 in the middle of inflation, the airbag 1 can be suitably received by suppressing the reaction force.

  Further, the inflator 10 of the first embodiment is configured to include a tank chamber 12 provided with a discharge port 22 and containing a pressurized gas G, and the pressure in the tank chamber 12 is increased in the tank chamber 12. An initiator 18 that can break the rupturable plate 23 is disposed. Therefore, when the normal operation of the inflator 10 is configured to be operated from the time of the collision prediction determined that the vehicle collision in the previous stage of the actual vehicle collision cannot be avoided, as described above, It can be used suitably. This is because, when an actual vehicle collision occurs without predicting a vehicle collision, as shown in FIG. 5, when the initiator 18 is operated, the rupturable plate 23 is ruptured and the discharge port 22 is opened. Can do. Therefore, from the beginning of the operation of the inflator 10, the pressurized gas G can be discharged from the discharge port 22 whose opening is fully opened, the airbag 1 can be quickly inflated, and the airbag 1 that has been completely inflated. This is because the person who is scheduled to restrain can be suitably received.

  In addition, like the inflator 10A of 2nd Embodiment shown in FIG. 6, you may comprise without providing an initiator. In such a configuration, it is only necessary to connect the signal line for inputting the operation signal from the control device to the flow rate adjusting mechanism 33 outside the tank chamber 12, and the signal line can be easily routed when the vehicle is mounted. In addition, the mounting space for the inflator 10A can be reduced. Incidentally, the cylindrical outer case 31 is provided on the flange portions 16 and 29 of the bottom wall portion 14 and the discharge side wall portion 20 that are disposed at both ends of the main body 11 so as to cover the periphery of the columnar main body 11 in this way. As a configuration in which the arrangement area of the signal line is opposite to the supply side of the gas for inflating the airbag 1, the configuration in which the signal line of the inflator can be easily handled and the mounting space can be reduced In this case, as shown in FIG. 7, the invention can also be applied to a conventional stored inflator 9 in which the rupturable plate 23 is ruptured by the initiator 18A.

It is a schematic longitudinal cross-sectional view which shows the inflator of 1st Embodiment of this invention. It is a general | schematic expanded partial longitudinal cross-sectional view of the inflator of 1st Embodiment. It is a general | schematic fragmentary sectional view explaining in order the normal operation | movement time of the inflator of 1st Embodiment. It is a graph which shows the mass flow rate at the time of the normal operation | movement of the inflator of 1st Embodiment. It is a general | schematic fragmentary longitudinal cross-section which shows the time of the action | operation of the initiator in the inflator of 1st Embodiment. It is a general | schematic expanded partial longitudinal cross-sectional view which shows the inflator of 2nd Embodiment. It is a general | schematic expanded partial longitudinal cross-sectional view which shows the modification of 2nd Embodiment.

Explanation of symbols

1 ... Airbag,
10, 10A ... Inflator,
12 ... Tank room,
22: Discharge port,
23 ... Rupture disc,
33 ... Flow rate adjusting mechanism,
34 ... Drive mechanism,
35 ... electromagnetic solenoid,
42 ... Needle,
43… Valve,
44 ... Outlet,
G: Pressurized gas.

Claims (5)

An inflator that incorporates a pressurized gas for inflation supplied to an airbag, breaks a rupturable plate that closed the discharge port during operation, and discharges the pressurized gas from the discharge port,
A flow rate adjustment mechanism capable of adjusting the flow rate of the pressurized gas discharged from the discharge port is disposed at a portion of the discharge port,
The flow rate adjusting mechanism is
A needle capable of breaking the rupturable plate by applying a tip on the moving side to the rupturable plate;
The discharge port opened by the needle is closed so that it can be opened and closed, and the opening area is smaller than the opening area of the discharge port, and the pressurized gas can be supplied to the airbag side when the discharge port is closed. A valve body with an outlet,
A drive mechanism for moving the needle and the valve body;
An inflator characterized by being provided with.   The said needle and the said valve body are integrally formed, and are hold | maintained at the said drive mechanism so that a movement along the direction orthogonal to the opening surface of the said discharge port is possible. The inflator described. It is provided with a tank chamber in which the discharge port is provided and the pressurized gas is incorporated,
The inflator according to claim 2, wherein the flow rate adjusting mechanism is disposed outside the tank chamber.   The inflator according to any one of claims 1 to 3, wherein the driving mechanism includes an electromagnetic solenoid. A tank chamber provided with the discharge port and containing the pressurized gas;
The inflator according to any one of claims 1 to 4, wherein an initiator capable of increasing the pressure in the tank chamber to break the rupturable plate is disposed in the tank chamber. .

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