JP5972045B2 - Gas generator - Google Patents

Description

  The present invention relates to a gas generator for a person restraining device such as an air bag system of a vehicle.

There are three known types of gas generators: a pyro type using a solid gas generating agent, a stored type using pressurized gas, and a hybrid type using both.
Among these, the pyro type using a solid gas generating agent is a mechanism that generates a combustion gas by igniting a solid gas generating agent or explosive disposed inside the housing, while the gas generating agent is held inside the housing. It is necessary to keep it airtight so that contact with the outside world (humidity) is cut off.

As a means for keeping the inside of the housing airtight, a method of closing a plurality of gas discharge ports with a seal tape is employed.
When the plurality of gas discharge ports are closed with the seal tape as described above, it is important to maintain the airtightness and to function to open all the gas discharge ports during operation.
That is, when pressure is applied due to combustion of the gas generating agent or explosive, a situation where a part of the sealing tape covering the plurality of gas discharge ports and nozzles is not cleaved should be avoided. However, as a result of slight differences in burst pressure due to processing tolerances and shapes of the gas discharge ports or variations in the thickness of the seal tape, it is possible that the seal tape that covers some of the gas discharge ports does not cleave.

As described above, when the seal tape is not cleaved and some of the gas discharge ports are not opened, the operation is not normally performed.
In Patent Document 1, a hole 3 is formed in a partition wall that partitions the combustion chamber 2 and the diffuser chamber 4, and the hole 5 is airtightly closed by a cover 7 attached from the combustion chamber 2 side. A weak line 9 is formed in the cover at a portion corresponding to the hole 3.
Even if the fragile line 9 is formed, in order to perform the releasability of a plurality of holes with high reproducibility, the control of the depth of the line groove is strictly required, which increases the cost and labor of manufacturing. The problem that exists is not solved.

US Pat. No. 4,886,293

  This invention makes it a subject to provide the gas generator which can reduce the man-hour in a manufacturing process and can obtain the output performance with good reproducibility.

The invention of claim 1 is a solution to the problem.
A gas generator in which ignition means and a gas generating agent are accommodated in a housing having a plurality of gas discharge ports, and the gas discharge port is closed with a seal tape attached from an inner wall surface of the housing. ,
Around the gas discharge port on the inner wall surface of the housing, a protrusion protruding inside the housing is formed,
The sealing tape is
It has a base material layer and an adhesive layer formed on its surface,
The thickness (t) of the pressure-sensitive adhesive layer is larger than the projection height (h) from the inner wall surface of the housing (t> h),
A range including the gas discharge port and the protrusion is covered with the seal tape, and the protrusion is located inside the pressure-sensitive adhesive layer of the seal tape.

The invention of claim 1 relates to the function of maintaining the hermeticity inside the housing by associating the structure of the seal tape with the inward projections (burrs at the time of processing) formed around the hole on the inner wall surface of the housing. It was possible to obtain both of the functions to ensure that the gas discharge port can be opened reliably.
Further, the protrusions may be formed continuously around the gas discharge port, or may be formed independently or in one place.

The protrusion is caused by, for example, a perforation process when forming a gas discharge port in the housing.
In the gas generator, the gas discharge port on the inner wall surface of the housing is drilled from the outside. At this time, an inward projection (burr during processing) is generated around the gas discharge port on the inner wall surface due to the drilling process.
Such protrusions are removed for reasons such as not damaging other components.
For example, when sealing the gas outlet from the inside, it will be damaged if the sealing tape is applied as it is, so the chamfering process or sanding process is performed to remove protrusions (burrs during processing). After that, the seal tape was stuck.

However, in the gas generator of the present invention, by adjusting the length of the protrusion and the thickness of the sealing tape (thickness of the adhesive layer), the sealing tape is not damaged, and one of a plurality of gas discharge ports is provided. Since the chamfering process for one can be omitted, the processing and assembly of parts has been dramatically improved compared to the previous one.
The housing used in the gas generator is made of stainless steel having a thickness of about 0.8 to 3 mm, or has a strength similar to that (made of iron or the like) from the viewpoint of pressure resistance.
In the drilling process, since mechanical drilling or punching is performed, a stable drilling operation is performed.
For this reason, in the process of drilling the housing to form the gas discharge port, the state of the inward projection (burr during processing) formed around the opening of the inner wall surface of the housing does not vary greatly, and the projection height In addition, the upper limit can be adjusted.

A sealing tape has a base material layer and the adhesive layer formed in the surface.
The base material layer is preferably made of aluminum, and may be made of stainless steel or copper.
The thickness of the base material layer is preferably 15 to 200 μm, and more preferably 20 to 100 μm.
A base material layer can raise intensity | strength by laminating | stacking the reinforcing material layer which consists of resin.
The reinforcing material layer is made of a resin such as polyester or polyethylene, and can be formed by laminating the resin on the base material layer. The thickness of the reinforcing material layer is preferably 5 to 100 μm.
The pressure-sensitive adhesive layer can be a layer made of a known synthetic resin adhesive. As the pressure-sensitive adhesive, silicone-based, rubber-based, and epoxy-based pressure-sensitive adhesives are preferable from the viewpoint of heat resistance and adhesiveness.
The thickness of the pressure-sensitive adhesive layer is preferably 20 to 100 μm, more preferably 30 to 80 μm.

The thickness (t) of the pressure-sensitive adhesive layer of the seal tape is set to be larger than the protrusion height (h) from the inner wall surface of the housing (t> h).
The ratio (h / t) between the protrusion height (h) and the thickness (t) of the pressure-sensitive adhesive layer is preferably 0.03 to 0.8, preferably 0.08 to 0.7, 0.1 -0.6 is more preferable.

Since the seal tape and the protrusion satisfy the above relationship, when the area including the gas outlet and the protrusion is covered with the seal tape, the protrusion is located inside the adhesive layer of the seal tape, and the base material layer Not reached.
For this reason, in the state before an operation | movement, the protrusion of a gas exhaust port does not damage the base material layer of a sealing tape, and moisture does not penetrate | invade from a gas exhaust port.
During operation, pressure is applied to the sealing tape from the inside of the housing, and at this time, the protrusions in the adhesive layer of the sealing tape are pressed so that the base material layer is pressed and cleaved, All gas outlets are opened reliably.

The invention of claim 4 is a solution to the problem.
An ignition means and a gas generating agent are accommodated in a housing having a gas discharge port, and the gas discharge port is closed with a seal tape attached from an inner wall surface of the housing,
The inside of the housing is divided into an ignition means chamber and a combustion chamber outside thereof by a partition wall having a plurality of communication holes,
Around the communication hole of the inner wall surface of the partition wall, a protrusion protruding inside the ignition means chamber is formed,
In the ignition means chamber, a container filled with a medicine constituting the ignition means is accommodated,
A container containing the medicine,
The thickness is larger than the height of the protrusion from the inner wall surface of the partition wall,
The bottom side is abutted and supported by the igniter, and the top side is abutted and supported by the housing top plate,
Provided is a gas generator in which the projection of the communication hole and the side surface of the container in which the medicine is accommodated are not in contact before operation but are opposed to each other at an interval to be contacted during operation.

  The invention according to claim 4 relates to a container filled with a medicine constituting the ignition means and an inward projection (burr during processing) formed around the communication hole of the inner wall surface of the partition wall. A function that enables the container to be surely broken can be obtained.

The partition wall is for separating the inside of the housing into a plurality of chambers (spaces), and may be a cylindrical partition wall, a cup-shaped partition wall, a plate-shaped partition wall, or a combination thereof.
The protrusions may be formed continuously around the communication hole, or may be formed independently or in one place.
The protrusion is caused by, for example, a perforation process when forming a gas discharge port in the housing.
The communication hole of the partition wall is drilled from the outside. At this time, an inward projection (burr at the time of processing) due to the drilling process is generated around the communication hole of the inner wall surface of the partition wall.
Such protrusions are removed for reasons such as not damaging other components.
However, by adjusting the length of the protrusion and the thickness of the container that contains the medicine that constitutes the ignition means, the chamfering process is omitted for each of the gas outlets without damaging the sealing tape. As a result, the processing and assembly of parts has been dramatically improved compared to previous products.

The partition wall used in the gas generator is made of stainless steel having a thickness of about 0.8 to 3 mm, or has a strength similar to that (made of iron or the like) from the viewpoint of pressure resistance.
In the drilling process, since mechanical drilling or punching is performed, a stable drilling operation is performed.
For this reason, in the step of drilling the partition wall to form the communication hole, there is no great variation in the state of the inward protrusion (burr during processing) formed around the communication hole on the inner wall surface of the partition wall, and the protrusion height is also The upper limit can be adjusted.

The internal space separated by the partition wall becomes an ignition means chamber, and a container filled with a medicine constituting the ignition means is accommodated.
The chemical | medical agent which comprises an ignition means is a well-known transfer agent and a gas generating agent.
Examples of the container include canisters made of aluminum, aluminum alloy, carbon steel, copper alloy, or the like. The canister is composed of a main body and a lid. An explosive or a gas generating agent is placed inside the main body, and the inside of the container can be maintained in a sealed state by closing the lid.
As the canister, a canister having a thickness of 50 to 400 μm can be used. For example, a thin aluminum plate cup 19 shown in FIG. 2 of JP-A-9-86330 and described in paragraph numbers 0021 to 0025 can be used. The transfer charge container 7 to which the cover 20 is joined can be used.
The cup 19 and the cover 20 may have a flange 21 and a flange 22, respectively.

The container filled with the medicine constituting the ignition means has a thickness larger than the height of the protrusion formed on the partition wall, particularly on the side surface facing the communication hole, and the bottom side is in contact with and supported by the igniter. The top surface is in contact with and supported by the housing top plate.
As a method for supporting the container as described above, for example, the method described in paragraph Nos. 0026 to 0027 of JP-A-9-86330 can be applied.

In the gas generator according to claim 4, the projection of the communication hole formed in the partition wall and the side surface of the container in which the medicine is accommodated are not in contact before the operation, and are spaced with an interval at which the contact is made in the operation. It is against.
At the time of operation, the igniter ignites the transfer agent (or gas generating agent) in the container, so that the container expands and deforms and hits the projection of the communication hole, so that the container is destroyed.

The gas generator of the present invention can reduce the number of man-hours in manufacturing.
In the gas generator of the present invention, all the gas discharge ports closed with the sealing tape by the pressure during operation are more easily opened.

Sectional drawing of the axial X direction of the gas generator of this invention. Explanatory drawing of the drilling method of the gas exhaust port in the gas generator of FIG. (A) is a partially enlarged view of the gas generator of FIG. 1 (enlarged view of a portion where the gas discharge port is closed with a seal tape), and (b) shows a teared state (dropped state) of the seal tape during operation. Figure. The elements on larger scale which are other embodiment of the gas generator of FIG. (A) is a partially enlarged view (an enlarged view of a portion where a gas discharge port is closed with a seal tape), which is another embodiment of the gas generator of FIG. 1, and (b) is a state in which the seal tape is opened during operation ( FIG. The enlarged view of the part containing the inner cylinder member in the gas generator of FIG.

(1) First Embodiment A gas generator according to the present invention includes a relationship between a plurality of gas discharge ports formed in a housing and a seal tape, a plurality of heat transfer holes (communication holes) formed in an inner cylinder, and a canister. The relationship with (the container filled with the chemical | medical agent which comprises an ignition means) is a novel thing, and another part is the same as a well-known gas generator.
The gas generator shown in FIG. 1 is the same as that shown in FIG. 1 of Japanese Patent Application Laid-Open No. 11-334517 except for the above-described new part. However, burrs (protrusions) exist on the inner surface of the gas discharge port 11 and the inner surface of the heat transfer hole (communication hole) 54, and this occurred in the drilling process of the gas discharge port 11 and the heat transfer hole 54. The burr remains without being removed. The seal tape 52 'that closes the heat transfer hole (communication hole) 54 of the inner cylinder member 16 from the outside is not used.

The housing 3 includes a diffuser shell 1 and a closure shell 2.
A gas discharge port 11 is formed in the peripheral wall portion 10 of the diffuser shell 1. The gas discharge port 11 is drilled from the outside by a drill or punch 70 as shown in FIGS.
When punching with a punch, the inner wall surface 10a of the peripheral wall is fixed with a die. The clearance between the punch and the die is preferably 5 to 10% of the thickness of the peripheral wall 10 and can be, for example, about 0.1 mm.
When perforated, as shown in FIG. 2C, a projection 40 is formed around the gas discharge port 11 on the inner wall surface 10 a side of the peripheral wall portion 10.
The protrusion 40 is a portion that is higher than the inner wall surface 10 a of the peripheral wall portion 10.
The protrusion 40 is, for example, an annular protrusion as shown in FIG. 3A, or a protrusion with a partially broken ring as shown in FIG. 4 or an independent protrusion arranged in an annular shape.
When stainless steel (SUS304) having a thickness of 1.5 mm is used as the housing 3 (diffuser shell 1), the height of the protrusion 40 can be adjusted to about 30 μm.

As shown in FIG. 3A or 4, the gas discharge port 11 is closed with a seal tape 52 attached from the inner wall surface 10 a side. This prevents outside air (humidity) from entering the housing 3 from the gas discharge port 11.
The seal tape 52 is formed on the base material layer 112, a reinforcing material layer 111 made of polyester film and having a thickness of 25 μm, a base material layer 112 made of aluminum foil formed on the reinforcing material layer 111, and a thickness of 15 μm. And an adhesive layer 113 having a thickness of 50 μm containing an acrylic adhesive.
Since the thickness (t) of the pressure-sensitive adhesive layer 113 is 50 μm and the height (h) of the protrusion 40 is 30 μm, h / t = 0.6.
For this reason, as shown in FIG. 3A or 4, all of the protrusions 40 are in a state of being cut into the pressure-sensitive adhesive layer 113, but have reached the base material layer 112 and the reinforcing material layer 111. Absent.

Further, as shown in FIG. 5A, the gas discharge port 11 may be closed by applying a seal tape 52 from the inner wall surface 10a side. Even in such a case, the outside air (humidity) is prevented from entering the housing 3 from the gas discharge port 11.
In FIG. 5A, the protrusion 40 is not attached so as to bite into the adhesive layer 113 as in FIG. 3A, but the adhesive layer 113 is attached along the protrusion 40. At this time, only the tip part (that is, only a part) of the protrusion 40 may be in a state of being bitten into the adhesive layer 113.

Next, the operation of the gas generator of FIG. 1 will be described.
The operation of the gas generator itself in FIG. 1 is known, but there is a difference in the cleavage state of the seal tape 52 that closes the gas discharge port 11.
When the gas discharge port 11 is closed with the seal tape 52 in the state of FIG. 3A, when the pressure from the arrow direction (pressure due to the combustion gas of the gas generating agent 6) is received during operation, the seal tape 52 As shown in FIG. 3 (b), the protrusion 40 is preferentially cleaved from the portion where the protrusion 40 is biting in and easily dropped off. Such protrusions 40 are formed in all the gas discharge ports 11.
For this reason, it is not difficult for some gas exhaust ports to be opened unlike the prior art, and all the gas exhaust ports 11 are easily opened.
The same applies to the embodiment shown in FIG. 4 and the embodiment shown in FIG.

(2) Second Embodiment An inner cylinder member (partition wall) 16 is disposed in the housing 3 so as to be coaxial with the central axis X of the housing.
The inner cylinder member 16 has an ignition chamber (ignition means chamber) 23 in which the igniter 4 and an aluminum canister 53 are accommodated. The canister 53 is filled with the transfer charge 5.
The canister 53 is 200 μm thicker than the thickness (90 μm) of the sealing tape 52 that closes the gas discharge port 11.
The canister 53 is supported by contact with the top plate 12 of the housing 3 on the top surface side, and is supported by contact with the igniter 4 on the bottom surface side.
Further, in the canister 53, an annular curved portion 53 a formed on the side surface on the bottom side is in contact with and supported by the inner wall surface 16 a of the inner cylinder member 16. Therefore, an annular gap having a width s is formed on the side surface of the canister 53 and the inner wall surface 16 a of the inner cylinder member 16.

A plurality of nozzles (communication holes) 54 serving as heat transfer holes are formed on the peripheral wall of the inner cylinder member 16. Since these nozzles 54 are perforated by the method described with reference to FIG. 2, protrusions 40 are formed around the nozzles 54 on the inner wall surface 16a. The protrusion 40 may be formed on the entire circumference of the nozzle 54, or a plurality of protrusions may be formed discontinuously. Moreover, you may form in one place. However, the height of the protrusion 40 from the inner peripheral surface 16 a is smaller than the thickness of the side surface of the canister 53.
The side surface of the canister 53 and the projection 40 of the nozzle 54 do not contact each other before the operation, but face each other with an interval (s) to the extent that they contact each other during the operation.

Next, the operation of the gas generator of FIG. 1 including the embodiment of FIG. 6 will be described.
When the igniter 4 is operated, the canister 53 is cleaved from the bottom surface, and the internal charge 23 is ignited and burned.
At the same time, as shown in FIG. 6B, the canister 53 expands and deforms in the outward direction and is cleaved at the portion where the side surface collides with the protrusion 40.
For this reason, the combustion product generated in the ignition chamber 23 is discharged from the nozzle 54 into the combustion chamber 28, and the gas generating agent 6 is ignited and combusted. Since the amount of deformation of the side surface portion of the canister 53 increases at the central portion in the axial direction (height direction), the nozzle 54 can also be disposed so as to face the central portion of the container side surface.

Since the gas generator of the present invention does not require chamfering (burr removal work) for the gas discharge port 11 formed in the housing 3 and the nozzle 54 formed in the inner cylinder member 16, the number of steps can be reduced. , Parts cost can be reduced.
In addition, the same airtightness maintaining effect as that of the conventional product can be obtained, and the gas discharge port closed by the seal tape is easily opened.

DESCRIPTION OF SYMBOLS 1 Diffuser shell 2 Closure shell 3 Housing 4 Igniter 5 Transfer agent 6 Gas generating agent 7 Coolant filter 9 Gap | interval 10 Peripheral wall part 11 Gas exhaust port 12 Top plate (circular part)
DESCRIPTION OF SYMBOLS 14 Axial direction bending part 15 Center hole 16 Inner cylinder member 19 Flange part 20 Flange part 21 Laser welding 23 Ignition means accommodation chamber 27 Caulking part 28 Combustion chamber 29 Outer layer 30 Bottom plate (circular part)
47 Peripheral wall 52 Sealing tape 53 Canister
54 Nozzle (through hole)
110 Retainer (partition member)

Claims (2)

A gas generator in which ignition means and a gas generating agent are accommodated in a housing having a plurality of gas discharge ports, and the gas discharge port is closed with a seal tape attached from an inner wall surface of the housing. ,
Around the gas discharge port on the inner wall surface of the housing, a protrusion protruding inside the housing is formed,
The sealing tape is
It has a base material layer and an adhesive layer formed on its surface,
The ratio (h / t) of the protrusion height (h) and the thickness (t) of the pressure-sensitive adhesive layer is 0.1 to 0.6,
A gas generator in which a range including the gas discharge port and the protrusion is covered with the seal tape, and the protrusion is located in a state of being cut into an adhesive layer of the seal tape. The sealing tape, and the reinforcement layer made of resin, and a base layer made of formed on the reinforcing material layer metal, and has a pressure-sensitive adhesive layer formed on the substrate layer, according to claim 1, wherein Gas generator.

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