Inflator and air bag device

An inflator (3) includes an inflator main body (10) which is has a tubular shape and has a plurality of gas injection holes (11) on a circumferential surface, and a steel-made collar member (20) which has a gas jet reception part (28) that is disposed so as to face a gas injection holes formation area (R) of the inflator main body (10) across a space.

BACKGROUND OF THE INVENTION

Field of the Invention

The present invention relates to an inflator and an air bag device.

Priority is claimed on Japanese Patent Application No. 2015-156280, filed Aug. 6, 2015, the content of which is incorporated herein by reference.

Description of Related Art

An air bag device is provided with a bag body to be a cushion and an inflator to supply a gas to inflate the bag body. For example, Patent Document 1 discloses an air bag device provided with an inflator main body which is tubal and has a plurality of gas injection holes on the circumferential surface. Such an air bag disclosed in Patent Document 1 adopts a structure to install a hook at a deflector which rectifies injected gas from the inflator, in order to prevent misalignment of the position with the bag body in the vicinity of the installation place of the inflator main body.

SUMMARY OF THE INVENTION

In Patent Document 1, the deflector is disposed so as to abut the circumferential surface of the inflator main body, causing a part of the gas injection holes formed on the circumferential surface of the inflator main body blocked by the deflector. In such a case, it may be difficult for the gas generated inside the inflator main body to be smoothly injected out towards the outside of the inflator main body. As a result, the velocity of the inflation and expansion of the bag body may be reduced slightly.

The present invention allows the gas generated inside the inflator main body to be smoothly injected out towards the outside of the inflator main body, even in cases where the collar member of the deflector or the like is fixed to the inflector main body in the inflator and the air bag device.

Aspects of the present invention adopt following structures.

According to a first aspect of the present invention, an inflator (inflator3of the embodiment, for example) includes an inflator main body (inflator main body10of the embodiment, for example) which has a tubular shape and has a plurality of gas injection holes (gas injection holes11of the embodiment, for example) on a circumferential surface, and a collar member (steel-made collar member20of the embodiment, for example) which has a gas jet reception part (gas jet reception part28of the embodiment, for example) that is disposed so as to face a formation area of the gas injection holes (gas injection holes formation area R of the embodiment, for example) of the inflator main body across a space.

In the first aspect of the present invention, the collar member is disposed so as to face the formation area of the gas injection holes of the inflator main body across a space. In this case, the collar member is prevented from directly block the gas injection holes, and also the collar member is prevented from obstructing the gas injection from the gas injection holes. Therefore, according to the present aspect of the present invention, it is possible to inject the gas from the inflator main body smoothly, even in the cases where the collar member of the deflector or the like is fixed to the inflector main body.

According to a second aspect of the present invention, in the above-described first aspect of the invention, the collar member has abutting parts (curb part23and linear rib24of the embodiment, for example) which abut the circumferential surface of the inflator main body at positions of point symmetry at an axis core of the inflator main body (axis core L of the embodiment, for example) as a center, in a cross section orthogonal to the axis core of the inflator main body.

When the gas injection holes are locally blocked by the abutting parts, injection amount of the gas seen from the axis core direction is not even in the circumferential direction of the inflator main body, and may generate thrust force to the inflator main body. When the thrust force is generated in this manner, position of the inflator main body may be misaligned. On the contrary, in the second aspect of the present invention, the abutting parts are provided at positions of point symmetry at an axis core of the inflator main body as a center. Thus, even when the gas injection holes are locally blocked by the abutting parts, gas injection amount decrease in the same manner on both sides interposing the axis core of the inflator main body. Due to this, reaction forces of gas injection received on both places interposing the axis core of the inflator main body is kept constant, preventing the generation of the thrust force with respect to the inflator main body. Therefore, according to the aspect of the present invention, it is possible to support the inflator main body stably even at the time of the gas injection.

According to a third aspect of the present invention, in the above-described first and second aspects of the invention, the gas jet reception part has notch parts (notch opening21, bottom bore opening22and end part notch26of the embodiment, for example) on both sides interposing the axis core, in the cross section orthogonal to the axis core of the inflator main body.

In the third aspect of the present invention, by the collar member with notch parts, even smoother gas injection is possible in the areas where notch parts are provided. Furthermore, the notch parts are provided on the both sides interposing the axis core in the cross section orthogonal to the axis core of the inflator main body. Due to this, reaction forces of gas injection received on both places interposing the axis core of the inflator main body counterbalances, preventing the generation of the thrust force with respect to the inflator main body. Therefore, according to the aspect of the present invention, it is possible to make the gas injection even smoother, and also to support the inflator main body stably even at the time of the gas injection.

According to a fourth aspect of the present invention, in the above-described third aspect of the invention, the collar member has a curved rib (curved rib25of the embodiment, for example) which is formed in a place displaced in the axis core direction of the inflator main body with respect to at least one among two of the notch parts and extends in a circumferential direction of the inflator main body.

For example, when mounting the collar member by expanding diameter to the inflator main body of the tubular shape, due to the low strength of the surrounding portions of the notch part, plastic deformation maybe caused to such portions. In such case, it causes yield to decrease. On the contrary, in the fourth aspect of the present invention, the curved rib extending in a circumferential direction of the inflator main body is provided in the surroundings of the notch part, which enhances the strength of the surroundings of the notch part, preventing the plastic deformation of the collar member at the time of mounting. Furthermore, it is possible to adjust the restoring force of the collar member by the curved rib when the diameter of the collar member is expanded.

According to a fifth aspect of the present invention, in the above-described third or fourth aspect of the invention, the collar member has a linear rib (linear rib24of the embodiment, for example) which is formed in a place displaced in the circumferential direction of the inflator main body with respect to at least one among two of the notch parts and extends in a direction of the axis core of the inflator main body.

In the fifth aspect of the present invention, the linear rib extending in a direction of the axis core of the inflator main body is provided in the surroundings of the notch part, which enhances the strength of the surroundings of the notch part, preventing the plastic deformation of the collar member at the time of mounting. Furthermore, it is possible to adjust the restoring force of the collar member by the linear rib when the diameter of the collar member is expanded.

According to a sixth aspect of the present invention, in any one of the above-described first to fifth aspect of the invention, a cover member (resin-made collar member30in the embodiment, for example) which is fixed to the inflator main body and covers an end part of the inflator main body from outside in a radial direction of the inflator main body is included, and the collar member has a position restriction part (projection part27of the embodiment, for example) which is configured to restrict a displacement by abutting on the cover member with respect to the inflator main body.

In the sixth aspect of the present invention, the position restriction part prevents the displacement of the collar member with respect to the inflator main body. Due to this, this aspect of the present invention enables to prevent the collar member from displacing with respect to the inflator main body at the time of the gas injection. Furthermore, it is possible to easily position the collar member with respect to the inflator main body at the time of assembly by using the position restriction part as a mark.

According to a seventh aspect of the present invention, a bag body and an inflator configured to inject a gas to inflate the bag body are included, and any one of the above-described first to sixth aspect of the invention is included as the inflator.

In the seventh aspect of the present invention, the inflator of any one of the above-described first to sixth aspect of the invention is included. Due to this, it is possible to inject the gas from the inflator main body and causes the bag body to inflate and expand as designed.

According to the inflator and air bag device of the aspects of the present invention, it is possible to inject the gas from the inflator main body smoothly, even in the cases where the collar member of the deflector or the like is fixed to the inflector main body.

DETAILED DESCRIPTION OF THE INVENTION

Hereinafter, referring to the drawings, an embodiment of an inflator and an air bag device related to the aspect of the present invention will be described. In the drawings being referred to below, the scale of each member is changed properly so that each member is shown in a recognizable size.

FIG. 1is a partial cross-sectional view of a vehicle in which an air bag device1of present embodiment is mounted. The air bag device1of the present embodiment is a SRS (Supplemental Restraint System) for a passenger seat, which is disposed in front of the passenger seat. As shown inFIG. 1, the air bag device1of the present embodiment is, for example, disposed inside the dash board100and above the air-conditioning unit200.

FIG. 2is a partially magnified view ofFIG. 1including the air bag device1of the present embodiment.FIG. 3is partially magnified view of the air bag device1of the present embodiment seen from a side of the dash board100, in which a bag body2which is to be referred to below is omitted. As shown in these drawings, the air bag device1includes a bag body2, an inflator3, a ring retainer4and retainer5. In the description below, a direction in which the bag body2is to be inflated and expanded (that is, a direction from retainer3towards the passenger seat) is referred to as the inflation and expansion direction, as may be necessary.

The bag body2is a component to be inflated and expanded towards the passenger seat at the time of vehicle collision, and support a passenger to alleviate the impact which the passenger may receive. As shown inFIG. 2, this bag body2accommodates the inflator3inside. And the dash board100accommodates the bag body2by folding up those portions of the inflation and expansion direction seen from the inflator3. The bag body2like this is inflated by a gas injected out from the inflator3and expanded towards the passenger seat side by breaking the dash board100. For example, this bag body2includes a bag-like main panel made of Nylon and a heat cloth laminated and disposed on the main panel, as may be necessary. The heat cloth is a sheet material of high heat resistance, and is installed in the vicinity of the inflator3, for example, to prevent the high temperature gas injected from the inflator3from hitting against the main panel directly.

The inflator3is a component to generate a gas by blowing up explosive accommodated inside according to instructions from ECU (Engine Control Unit), for example, and to inject and supply the gas to the bag body2to expand the bag body2. The inflator3is substantially in circular tubal shape (cylindrical shape) as a whole, and accommodated inside the bag body2so that an axis core direction is along a vehicle width direction. Regarding the inflator3, details will be described later.

The ring retainer4is a component which is disposed between the bag body2and the inflator3. As shown inFIG. 2, the ring retainer4is disposed on an opposite side of the inflation and expansion direction of the bag body2seen from the inflator3. The ring retainer4as above, by receiving the gas injected towards the opposite side of the inflation and expansion direction of the bag body2, prevents the gas from directly hitting the bag body2.

The retainer5is a metal-made container, opening in the inflation and expansion direction of the bag body2, which accommodates the bag body2together with the inflator3and the ring retainer4. As the retainer5opens in the inflation and expansion direction of the bag body2, the retainer5guides an expansion direction of the bag body2towards the passenger seat side. The retainer as above is fixed to the vehicle body by being hooked to the dash board100, for example. In this way, by fixing the retainer5to the vehicle body, the air bag device as a whole is fixed to the vehicle body.

Following, referring to theFIGS. 4 to 7, the inflator3will be described more in details.FIG. 4is an overall view of the inflator3.FIG. 4A is a plan view seen from the side of the inflation and expansion direction.FIG. 4B is a side view seen from the orthogonal direction to the inflation and expansion direction.FIG. 4C is a bottom plan view seen from the opposite side of the inflation and expansion direction. In addition,FIG. 5is a cross-sectional view of the inflator3.FIG. 5A is a cross-sectional view along A-A line indicated inFIG. 4A.FIG. 5B is a cross-sectional view along B-B line indicated inFIG. 4A.

As shown inFIG. 4, the inflator3includes an inflator main body10, a steel-made collar member20and a resin-made collar member30(cover member). The inflator main body10is a component in substantially a circular tubal shape (cylindrical shape) as a whole. The inflator main body10is provided with an accommodation chamber or the like to accommodate the explosive inside and ignition equipment or the like to ignite the accommodated explosive. The inflator main body10as above has a multiple number of gas injection holes11to inject the gas generated inside towards the outside. The gas injection holes are formed with a predetermined pitch in the circumferential direction and in the axis core direction on the circumferential surface of the inflator main body10. Thus, the gas generated inside the inflator main body10is dispersed and injected out from plural places in the circumferential direction and in the axis core direction. Additionally, in the present embodiment, the gas injection holes11are formed in an area of a central part except for end part (area where the resin collar30is installed) of the inflator main body10. Hereinafter, the area of the central part of the inflator main body10where the gas injection holes11are formed is referred to as gas injection holes formation area R.

The steel-made collar member20is a component attached in the gas injection holes formation area R, and disposed between the resin-made collar members fixed to the end part of the inflator main body10.FIG. 6is a perspective view of the steel-made collar member20.FIG. 7is a plan view of the steel-made collar member20seen from the side of the inflation and expansion direction (that is, from the passenger seat side).

The steel-made collar member20is a component made of steel material, and in substantially circular tubal shape (cylindrical shape) surrounding the inflator main body10. The steel-made collar member20has a notch opening21(notch part), formed in the inflation and expansion direction. The notch opening is formed along the full length of the steel-made collar member20in the axis core direction. As the notch opening21is formed, cross-sectional shape of the steel-made collar member20is substantially in C-shape (refer toFIG. 5). Also, the steel-made collar member20has a bottom bore opening22(notch part) on an opposite side of the notch opening21(that is, opposite side of the inflation and expansion direction of the bag body2). The notch opening21and the bottom bore opening22are formed, interposing an axis core L (refer toFIG. 5). Either one of the notch opening21and the bottom bore opening22corresponds to the notch part of the aspect of the present invention. That is to say, in the present embodiment, the notch parts are formed on both sides interposing the axis core L of the inflator main body10.

Also, as shown inFIG. 6, curb parts23(abutting parts) of the steel-made collar member20, which is fronting the notch opening21and is locally curved, protrude inwards in the radial direction of the inflator main body10. These curb parts23as above are made to be abutting parts which abut the circumferential surface of the inflator main body10. Also, in a place displaced in the circumferential direction of the inflator main body10with respect to the bottom bore opening22which is one among the two notch parts, linear ribs24are formed extending in a linear fashion along an edge of the bottom bore opening22(that is, along the axis core direction of the inflator main body10). There linear ribs24reinforce the steel-made collar member20, are made to be abutting parts which abut the circumferential surface of the inflator main body10. That is to say, the linear ribs24protrude inwards in the radial direction of the inflator main body10at the similar height as those of the curb parts23. In addition, the linear ribs24abut the circumferential surface of the inflator main body10in a similar way as the curb parts23.

As shown inFIG. 5, two of the curb parts23and two of the linear ribs24which function as the abutting parts are aligned with an equal pitch in the circumferential direction. That is, in the present embodiment, the steel-made collar member24has abutting parts against the inflator main body10at positions of point symmetry at the axis core L as a center (positions located in the opposite direction from the center, and the distance of the positions from the center is the same), in a cross section orthogonal to the axis core L of the inflator main body10. Also, an inscribed circle in contact with tips of two of the curb parts23and two of the linear ribs24is made to be slightly smaller in diameter than the inflator main body10. In this way, when attaching the steel-made collar member20to the inflator main body10, two of the curb parts23and two of the linear ribs24are pressed against the circumferential surface of the inflator main body10by restoring force of the steel-made collar member, and position of the steel-made collar member is stabilized.

Also, as shown inFIGS. 6 and 7, the steel-made collar member20has curved ribs25extending in the circumferential direction of the inflator main body10. Four of curved ribs25are formed, aligned in a coaxial direction, including the position displaced in the axis core direction of the inflator main body10with respect to the bottom bore opening22. These curved ribs25reinforce the steel-made collar member20. The curved rib25may be made to abut the inflator main body10by making the same amount of protrusion as the liner rib24. Also, for example, the curbed rib25may be made not to abut the inflator main body10by reducing the amount of protrusion compared to that of the linear rib24. In case making the curved rib25with the same amount of protrusion as that of the linear rib24to abut the inflator main body10, three places which are the curb part23, the linear rib24and the curved rib25are made to abut the inflator main body10. In this way, the curb part23, the linear rib24and the curved rib25are pressed against the inflator main body10by the restoring force of the steel-made collar member20. For this reason, the position of the steel-made collar member20with respect to the inflator main body10is stabilized by a so-called three-contact spring effect, and thus, it is possible to prevent displacement by vehicle vibration or the like, or generation of noise.

In the steel-made collar member20as above, the bottom bore opening22is surrounded by the linear rib24and the curved rib25. Thus, decrease of strength by forming the bottom bore opening22is possible to be compensated by the linear rib24and the curved rib25. Furthermore, by adjusting the diameter or number of the linear rib24and the curved rib25, it is possible to adjust restoring force when the steel-made collar member20is expanded its diameter. The steel-made collar member20is expanded its diameter so as to expand the notch opening21at the time of attaching to the inflator main body10. Therefore, the diameter or the number of the linear rib24and the curved25are set so that the restoring force after attaching is to be a proper retaining force for the steel-made collar member24to being fixed to the inflator main body10.

Also, the steel-made collar member20has an end part notch26(notch part) in an end part of one side as shown inFIG. 4C. The end part notch26is, like the bottom bore opening22, formed on the opposite side of the notch opening21interposing the axis core L of the inflator main body10. The end part notch26, like the notch opening21and the bottom bore opening22, corresponds to the notch part of the aspect of the present invention. That is to say, in the present embodiment, the notch parts are formed on both sides interposing the axis core L of the inflator main body10, also in the end part of the steel-made collar member20.

Also, the steel-made collar member20has a projection part27(position restriction part) which projects in the axis core direction of the inflator main body10at an opposite end part of the end part at which the end part notch26is formed. The projection part27is disposed so as to intrude into inside of a concave part30a, which is to be described later. By this, when the steel-made collar member20is to move in the circumferential direction with respect to the inflator10, and when the steel-made collar member20is to move towards the side of the resin-made collar member30where the concave part30ais formed with respect to the inflator10, the projection part27and the resin-made collar member30interfere with each other, resulting in restricting of the movement of the steel-made collar member20.

In the steel-made collar member20as above, excluding two of the curb parts23, two of the linear ribs24which function as the abutting parts and the projection part27, an area facing the gas injection holes11of the inflator main body10functions as a gas jet reception part28to receive the injected gas from the gas injection holes11. As shown inFIG. 5, the gas jet reception part28as above is disposed so as to face the circumferential surface of the inflator main body10across a predetermined space (There is a space between the gas jet reception part28and the circumferential surface of the inflator main body10) because two of the curb parts23and two of the linear ribs24which function as the abutting parts abut the inflator main body10. That is to say, in the present embodiment, the steel-made collar member20has the gas jet reception part28that is disposed so as to face the gas injection hole formation area R, where the gas injection holes11of the inflator main body10are formed, across a space.

As shown inFIG. 4, the resin-made collar member30are components fixed to each of the end part of the inflator main body10, and is formed of resin. Each of the resin-made collar members30is disposed so as to cover the inflator main body10from the outside in the radial direction. As shown inFIG. 4A, among these two of the resin-made collar member30, one of the resin-made collar member30disposed on the side of the projection part27of the steel-made collar member20has the concave part30ain which the projection part27is disposed.

In the air bag device1of the present embodiment as above configuration, when a signal to indicate a collision is input to the inflator main body10from the ECU which is not shown in drawings, explosive accommodated inside the inflator main body10is ignited by ignition equipment and gas is generated. The gas generated inside the inflator main body10in this way is injected out from the gas injection holes11and supplied to the bag body2. By this way, the bag body2is inflated and expanded.

Here, the air bag device1and inflator3of the present embodiment includes the inflator main body10which has the tubular shape and has a plurality of gas injection holes11on the circumferential surface, and the steel-made collar member20which has the gas jet reception part28that is disposed so as to face the gas injection holes formation area R of the inflator main body10across a space. That is, in the air bag device1and inflator3of the present embodiment, the steel-made collar member20is disposed so as to face the gas injection holes formation area R of the inflator main body10across a space. Thus, it is prevented that the steel-made collar member20directly block the gas injection holes11, and also it is prevented that the steel-made collar member20obstructs the gas injection from the gas injection holes11. Therefore, according to the air bag device1and the inflator3of the present embodiment, it is possible to inject the gas from the inflator main body10smoothly, even in the cases where the steel-made collar member20is fixed to the inflector main body10.

Also, injected gas from the inflator main body10is at high temperature as generated by combustion of explosive. On the contrary to this, the maximum temperature of the steel-made collar member20within the actual operating range is far lower compared to the temperature of the gas. Therefore, by hitting the injected gas from the inflator main body10against the steel-made collar member20once, it will enable lowering of the temperature of the gas hitting the bag body2. Therefore, according to the air bag device1and inflator3of the present embodiment, it is possible to reduce the heat influence to the bag body2, and also possible to alleviate the countermeasure against heat of the bag body2. Especially in the air bag device1and inflator3of the present embodiment, the steel-made collar member20has a shape to cover the entire area lateral (a side in the direction orthogonal to the inflation and expansion direction of the bag body2) to the gas injection holes formation area R. Therefore, it is possible to reduce the temperature of the gas injected from the lateral side and supply to the bag body, and enables the gas in high temperature state to be prevented from hitting the bag body2.

Also, in the air bag device1and inflator3of the present embodiment, the steel-made collar member20has the abutting parts (the curb part23and the linear rib24) which abut the circumferential surface of the inflator main body10at positions of point symmetry at the axis core L of the inflator main body10as the center, in the cross section orthogonal to the axis core L of the inflator main body10. By this way, as the same amount of gas is injected on both sides interposing the axis core L of the inflator main body, reaction forces of gas injection received on both places interposing the axis core L of the inflator main body10is kept constant, preventing the generation of the thrust force with respect to the inflator main body10. Therefore, it is possible to support the inflator3even at the time of gas injection.

Also, in the air bag device1and inflator3of the present embodiment, the steel-made collar member20(that is, the gas jet reception part28) has the notch parts (the notch opening21, the bottom bore opening22and the end part notch26) on both sides interposing the axis core L, in the cross section orthogonal to the axis core L of the inflator main body10. Due to this, even smoother gas injection outwards is possible. In addition, in places where the notch parts are provided, reaction forces of gas injection counterbalances interposing the axis core L of the inflator main body10, preventing the generation of the thrust force with respect to the inflator main body10. Therefore, according to the air bag device1and inflator3of the present embodiment, it is possible to make the gas injection even smoother, and also possible to support the inflator3stably even at the time of gas injection.

Also, the air bag device1and inflator3of the present embodiment includes the curved rib25which is formed in the place displaced in the axis core direction of the inflator main body10with respect to the bottom bore opening22and extends in the circumferential direction of the inflator main body10. This enhances the strength of the surroundings of the bottom bore opening22, preventing the plastic deformation of the steel-made collar member20at the time of mounting to the inflator main body10.

Furthermore, it is possible to adjust the restoring force of the steel-made collar member20by the curved rib25when the steel-made collar member is expanded its diameter. For example, it is possible to adjust an opening angle (an opening width of the notch opening21) in case where the steel-made collar member20is opened by a certain amount of force. That is to say, with the curved rib25provided, by adjusting the cross-sectional shapes of the places where the curved ribs25are formed and changing section modulus, it is also possible to adjust the opening angle in case where the steel-made collar member20is opened. Due to this, it is possible to adjust the opening angle of the steel-made collar member20at the time of gas injection, which also makes it possible to adjust the opening angle of the steel-made collar member20so that the gas is injected properly.

Also, the air bag device1and inflator3of the present embodiment includes the linear rib24which is formed in the place displaced in the circumferential direction of the inflator main body10with respect to the bottom bore opening22and extends in the direction of the axis core of the inflator main body. This enhances the strength of the surroundings of the bottom bore opening22, preventing the plastic deformation of the steel-made collar member20at the time of mounting to the inflator main body10. Furthermore, it is possible to adjust the opening angle of the steel-made collar member20.

Also, the air bag device1and inflator3of the present embodiment includes the resin-made collar member30which is fixed to the inflator main body10and covers the end part of the inflator main body10from outside in the radial direction of the inflator main body10, and the steel-made collar member20has the projection part27which is configured to restrict the displacement by abutting on the resin-made collar member30with respect to the inflator main body10. This enables to prevent the steel-made collar member20from displacing with respect to the inflator main body10at the time of the gas injection. Furthermore, it is possible to easily position the steel-made collar member20with respect to the inflator main body10at the time of assembly by using the projection part27as a mark.

As above, preferable embodiment of the aspect of the present invention is described, referring to the drawings, however, the scope of the present invention is not limited to the embodiment described above. Shapes, combinations or the like of each constituent element indicated in the above-described embodiment is an example, and various modifications according to the design requirements or the like is possible without departing from the scope of the invention.

For example, in the above embodiment, an example to apply the air bag device and inflator of the aspect of the present invention to SRS (Supplemental Restraint System) for a passenger seat is described. However, the present invention is not limited thereto, and may apply to other air bag devices.

Also, in the above embodiment, an example in which the collar member of the aspect of the present invention is the steel-made collar member20is described. However, the present invention is not limited thereto, and may apply a collar member made of material other than steel.