JPH0564015U - Cylindrical gas generator - Google Patents

Abstract

(57) [Summary] [Purpose] To provide a cylindrical gas generator which has improved filter efficiency, is small and lightweight, and is suitable for mass production. [Structure] An inner cylinder 2 and an outer cylinder 3 sharing a central axis are integrated by both end members 12 and 13, a gas generating agent 7 and the like are housed in the inner cylinder 2, and an annular shape between the inner cylinder 2 and the outer cylinder 3. The filters 4, 5 and 6 are housed in the space portion 14, and the first gas hole 2a on the outer periphery of the inner cylinder 2
In the cylindrical gas generator 1 provided with the second gas hole 3a on the outer circumference of the outer cylinder 3, the first gas hole 2a is provided at a predetermined azimuth angle of the inner cylinder 2, and the second gas hole 3a is formed at the predetermined azimuth angle. And the filters 4, 5, which are provided at azimuth angles different in phase from each other.
6 is characterized by being laminated and arranged in the circumferential direction from the first gas hole 2a to the second gas hole 3a.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cylindrical gas generator that is used by incorporating it into an airbag safety device of an automobile.

[0002]

[Prior Art]

 There are two types of airbag safety devices for automobiles, one for the driver's seat and one for the passenger's seat. Due to the relationship between the storage space and the required gas capacity, a compact short cylindrical gas generator is used for the driver's seat and for the passenger's seat. Relatively large cylindrical gas generators are often used. The configuration of the passenger airbag safety device will be described with reference to FIG. The airbag safety device 30 is a unit in which a cylindrical gas generator 31 and an air bag 32 are housed in a base 33 and a cover 35 and integrated, and is attached to a dashboard 34 or the like. The airbag 32 is inflated like a balloon at the time of a collision and serves as a cushioning material between the structural parts inside the vehicle and the occupant, and is normally folded small and stored in the cover 35. The air bag 32 and the base 33 are airtightly mounted, and a cylindrical gas generator 31 is provided in an airtight space between the air bag 32 and the base 33. Further, the cover 35 is provided with a notch or a thin portion so as to be expanded (opened) when the airbag 32 is inflated.

Next, an example of a conventional cylindrical gas generator will be described with reference to FIGS. FIG. 7 is a vertical sectional view of a conventional cylindrical gas generator, and FIG. 8 is a view taken in the direction of arrow B in FIG. The cylindrical gas generator 41 is composed of an inner cylinder 42 and an outer cylinder 43 that share a central axis and are integrated by caulking, screwing, pressure welding, etc. at both end members 48, 49. An electric heater 46 that is operated by receiving a current supply through a collision sensor (not shown) An igniting agent 47 that surrounds the above is contained and constitutes ignition means. An annular filter 44 is housed in the annular space between the inner cylinder 42 and the outer cylinder 43. The filter 44 is made of wire mesh, steel wool or the like. Further, as shown in FIG. 8, a first gas hole 42a is provided only in a predetermined direction on the outer circumference of the inner cylinder 42, and a second gas hole 43a is provided on the outer circumference of the outer cylinder 43 in the opposite direction. These are provided over almost the entire length in the axial direction as shown in FIG.

The operation of the above cylindrical gas generator 41 will be described with reference to FIGS. 7 and 8. The hot air of the igniting agent 47 ignited by the electric heater 46 breaks the partition 50 and enters the gas generating agent 45 storage portion, and the heat causes the gas generating agent 45 to undergo a chemical reaction to be gasified. This gas flow passes through the gas holes 42a of the inner cylinder and flows out into the annular space between the inner cylinder 42 and the outer cylinder 43. The gas flow passes through the filter 44 while moving in the annular space in the circumferential direction, and the cooling is performed between them. The slag is collected and ejected from the gas hole 43a of the outer cylinder 43 into an air bag (not shown).

Next, the collection of slag and the cooling of gas in the above-mentioned cylindrical gas generator 41 will be described in more detail. In order to deploy the airbag, a large amount of gas containing slag (dust after combustion of the gas generating agent) as well as high temperature is generated in a short time. If discharged as it is, hot gas leaking from the airbag may fill the inside of the vehicle, or slag may adhere to the airbag and cause a hole. Therefore, it is necessary to collect the slag and to cool the gas, but it is necessary to have a method that can withstand high temperatures and has a high slag collection rate. As a method of satisfying such requirements to some extent, a method of collecting slag and cooling gas by a filter using wire mesh, steel wool, etc. is adopted as described above. Further, the first gas hole 42a of the inner cylinder 42 and the second gas hole 43a of the outer cylinder 43 are provided in opposite directions in order to increase the filter efficiency by lengthening the gas outflow path as much as possible.

[0006]

[Problems to be solved by the device]

 The method of simply collecting the slag and cooling the gas with the filter like the cylindrical gas generator 41 described above requires a large amount of filters, and as a result, the entire gas generator becomes large. ..

The present invention has been made in view of the above problems of the prior art, and an object of the present invention is to enhance the efficiency of the filter and reduce the size and weight of the cylindrical gas generator. To provide.

[0008]

[Means for Solving the Problems]

 In order to solve the above-mentioned problems, the cylindrical gas generator in the present invention has an inner cylinder having a central axis and an outer cylinder integrated at both end members, and a gas generating agent is stored in the inner cylinder. A filter is housed in an annular space between the outer cylinder and the outer cylinder, and a first gas hole is provided at a predetermined azimuth angle of the inner cylinder. In the cylindrical gas generator provided with, there is a third gas hole in the middle of the annular space portion from the first gas hole to the second gas hole, and the annular space portion is partitioned by extending in the radial direction. It is provided with a partition plate.

[0009]

[Action]

 By providing a partition plate with gas holes in the annular space between the inner and outer cylinders as an obstruction to the gas flow path, there is a place near the partition plate where slag tends to collect, and the gas flow simultaneously. As the slag stagnates and the flow velocity is reduced, the slag can be easily captured by the filter. As a result, the collection rate of slag can be increased.

[0010]

【Example】

 Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a vertical cross-sectional view of a cylindrical gas generator of the present invention, and FIG. 2 is a view on arrow A of FIG. 3 is a diagram showing a partition plate of the present invention, and FIG. 4 is a cross-sectional view of a cylindrical gas generator using friction welding of the present invention.

In FIG. 1, a cylindrical gas generator 1 is composed of an inner cylinder 2 and an outer cylinder 3 that share a central axis and are integrated by friction welding 10 at both end members 12 and 13. Details of integration by friction welding will be described later. Welding, caulking, screwing, etc. can also be used as this integration method. Aluminum alloy or the like is used as a material for the inner cylinder 2 and the outer cylinder 3. At one end of the inner cylinder 2, an electric heater 8 that operates by receiving a current supply via a collision sensor (not shown), and an ignition charge 9 that surrounds the electric heater 8 constitute an ignition means. The gas generating agent 7 occupies most of the inner cylinder 2 and is accommodated through the rupturable partition 18.

Further, as shown in FIG. 2, a first gas hole 2a is provided only in a predetermined orientation on the outer circumference of the inner cylinder 2, and a second gas hole 3a is provided on the outer circumference of the outer cylinder 3 in the opposite orientation. These gas holes are provided in the axial direction over almost the entire length as shown in FIG. This lengthens the gas outflow route. Here, the first gas hole 2a is provided at a predetermined azimuth angle of the inner cylinder 2, and the second gas hole 3a is provided at an azimuth angle different in phase from the predetermined azimuth angle, as described above. It is also possible that the gas does not flow from the first gas hole 2a to the second gas hole 3a in opposite directions on both sides of the annular space portion 14, but may flow in one direction in almost one round. That is, this is a method in which the orientations of the gas holes of the inner cylinder 2 and the outer cylinder 3 are shifted to the minimum required so that they do not overlap, and a partition plate having no gas holes is installed between them. With this method, the gas outflow path can be maximized.

Then, in the annular space portion 14, from the first gas hole 2a to the second gas hole 3a, the first filter 4, the second filter 5, and the third filter 3 are symmetrical with respect to the first gas hole 2a. The filters 6 are sequentially arranged, a space 15 is formed between the inner cylinder 2 and the first filter 4, and a space 16 is formed between the inner cylinder 2 and the third filter 6. Further, between the first filter 4 and the second filter 5, two partition plates 11 having the third gas holes 11a are arranged.

The first filter 4 is a curved plate having an arc shape, and a space 15 is formed between the first filter 4 and the inner cylinder 2 for the purpose of trapping slag by inertia. That is, the gas flowing out from the first gas hole 2a hits the first filter 4, and the gas changes its direction to proceed through the space 15, but the slag with large inertia goes straight and is captured by the first filter 4. It is commonly used for primary collection of lugs and primary cooling of gases. Therefore, as the first filter 4, a wire mesh having a relatively coarse mesh, a three-dimensionally bent wire rod, or the like is used. Further, the space 15 also makes the stagnation of the gas flow by the partition plate 11 described later more effective. The stagnation effect is greater when the space 15 is wider, but since the slag collection due to inertia has an optimum value, the size of the space 15 is determined in consideration of both.

The partition plate 11 preferably has a thickness of 2 to 10 mm. If it is less than 2 mm, the strength is insufficient, and if it exceeds 10 mm, the space is wasted. FIG. 3 shows an example of the shape and arrangement of the third gas holes 11a opening in the partition plate 11. In FIG. 3, the number, shape, opening area, arrangement, etc. of the gas holes 67a are determined according to the gas generation amount, filter arrangement, and the like. Further, regarding the gas holes, for example, when the gas flows in only one direction in FIG. 2, one gas hole may not be opened and the other gas hole may be opened. Two partition plates 11 are required for friction welding, which will be described later, but three or more partition plates may be installed, and the arrangement thereof is determined according to the filter arrangement and the like. The method of fixing the partition plate 11 to the inner cylinder 2 and the outer cylinder 3 will be described later. The partition plate 11 acts as an obstacle to the gas flow, and a place 11b where slag is likely to collect is formed in the vicinity of the partition plate 11. At the same time, since the gas flow stagnates and the flow velocity is reduced, the slag can be easily captured by the first filter 4. As a result, the collection rate of slag can be increased. Further, these partition plates 11 are also used to hold and position the inner cylinder 2 with respect to the outer cylinder 3 during friction welding.

The second filter 5 is a shallow arc-shaped curved plate, and has the purpose of collecting fine slag by cooling by contact and filtration, and therefore has a relatively fine mesh, a three-dimensionally bent thin wire, etc. It is used that is laminated in the circumferential direction.

The third filter 6 is a curved plate having an arc shape, and has metal plates 17 for sealing at both ends. The third filter 6 is arranged so as to form a space 16 between the third filter 6 and the inner cylinder 2 so as to close the second gas hole 3a. The purpose of the third filter 6 is to collect slag by cooling by contact and filtration, but the main purpose is to collect fine slag. A bent thin wire rod, a sintered filter, or the like laminated in the radial direction is used. Figure 5 shows a specific example. In FIG. 5, the filter 80 is formed by laminating the inner wire mesh layer 82, the sintered filter 83, and the outer wire mesh layer 84, and further disposing the metal plates 81 (corresponding to 17 in FIG. 2) for sealing at both ends. It is pressed by the press dies 86 and 87 to be integrally molded, and at the same time, spot welded by the spot welder 88 and fixed to each other. Here, spot welding may be performed when the materials are superposed before pressing. The inner wire mesh layer 82, the sintered filter 83, and the outer wire mesh layer 84 may be annealed at the time of pressing or before pressing in order to improve moldability. Both wire mesh layers 82 and 84 are made of stainless wire mesh having a wire diameter of 0.2 to 1.0 mm, 10 × 10 mesh to 50 × 50 mesh, and 1 to 10 sheets of them are stacked. One to three sintered filters are stacked. The metal plate 81 is made of stainless steel, aluminum, or SS material, and has a thickness of 0.2 to 1.0 mm. The arc center angle of the filter is 90 ° to 180 ° depending on the arrangement of the second gas holes 3a. The metal plate 81 prevents the gas from flowing into the end portion from the circumferential direction to form a short path, and at the same time, the protrusion 81a secures an appropriate space between the metal plate 81 and the second filter 5 to allow the gas to reach the space 16. This is to make it easier to flow.

In FIG. 2, the space 16 allows the gas to sufficiently flow to the center of the third filter 6 so that the entire third filter 6 can be effectively used, and the gas flow can be prevented from flowing out of the second gas hole 3a. This is to stagnate here to reduce the flow velocity before the eruption to slag and increase the collection rate of slag.

Next, the operation of the cylindrical gas generator 1 having the above-mentioned configuration will be described with reference to FIGS. 1 and 2. In FIG. 1, the hot air of the ignition powder 9 ignited by the electric heater 8 breaks through the partition 18 and enters the housing for the gas generating agent 7, and the heat causes the gas generating agent 7 to undergo a chemical reaction to generate high temperature and slag. Generates a large amount of contained gas in a short time. In FIG. 2, this gas flow is jetted into the space 15 from the gas hole 2a of the inner cylinder and is blown onto the first filter 4. Here, due to the inertia, a large slag is collected by the first filter 4, the gas flow is divided into two parts, turns in the circumferential direction, and advances in the space 15. The entire gas is effectively cooled by the collection of the large slag having a large heat capacity. Then, the gas flow reaches the partition plate 11 and is obstructed, and stagnates as a whole. In this case, since the gas flow is a high-pressure gas, the entire space including the space 15 and the first filter 4 is immediately filled and a constant pressure state is generated. However, as compared with the case where the partition plate 11 is not provided, Reduce flow rate. As a result, the slag is easily captured by the first filter 4, and there is a place where the flow is stagnant, such as 11b near the partition plate 11, where the slag collects and the slag collection rate increases. .. Next, the gas flow, which has been increased to a constant pressure, increases its flow rate in the third gas hole 11a opening in the partition plate 11 and is jetted to the second filter 5, and passes through the filter 5 while diffusing and decreasing the flow rate. However, during this time, secondary cooling and fine slag collection are performed. Further, the gas flow reaches the space 16, and the gas moving in the circumferential direction by splitting into two joins and passes through the third filter 6, but the space 16 is wide enough so that the gas flow stagnates and the flow velocity is reduced. 3 The slag collection rate of the filter 6 increases. Then, the third filter 6 collects fine-grained slag that could not be completely removed by the first and second filters 4 and 5 and performs tertiary cooling, so that the second gas hole 3a of the outer cylinder 3 contains less harmful substances. Gas of appropriate temperature is supplied to the airbag.

As described above, in the cylindrical gas generator 1 having the above-described configuration, the partition plate 11 having the gas holes 11 a is provided in the annular space portion 14 between the inner cylinder 2 and the outer cylinder 3 to obstruct the gas flow path. By so doing, a place 11b where slag is likely to collect is generated near the partition plate 11, and at the same time, the gas flow stagnates and the flow velocity is reduced, so that the slag can be easily captured by the first filter 4. Further, by forming the spaces 15 and 16 in the annular space portion 14, the stagnation of the gas flow is assisted. As a result, the collection rate of slag can be increased. Furthermore, three types of filters are arranged in the annular space portion 14 to perform slag collection suitable for each stage, and the slag collection rate can be increased. As a result, the overall filter efficiency is improved, and the cylindrical gas generator 1 can be reduced in size and weight.

Next, the integration of the cylindrical gas generator of the present invention using friction welding will be described. 1, the cylindrical gas generator 1 is composed of both end members 12, 13, an inner cylinder 2, an outer cylinder 3, and a partition plate (holding member) 67 (corresponding to the partition plate 11 in FIG. 2) in FIG. It The inner cylinder 2, the outer cylinder 3, and the joints between the end members 12 and 13 are integrated by friction welding 10 sharing the central axis and located on the circumference of each. The groove shapes of the both end members 12, 13, the inner cylinder 2, and the outer cylinder 3 are symmetrical with respect to the joint surface, and the joint portion has a concave shape. This is to prevent burrs formed at the joint from protruding from the material surface and contacting other parts. Both end members 12 and 13 are lid-shaped discs having short cylindrical portions 12b, 12a, 13b, and 13a sharing the central axis and corresponding to the inner cylinder 2 and the outer cylinder 3, respectively. The length of the short cylindrical portions 12b, 12a, 13b, 13a is appropriately selected within a range in which cold forging can be performed. In this way, by dividing the whole into three parts and constructing the main body with the end members 12 and 13 and the intermediate cylindrical portions 2 and 3, the length of the cylindrical portion to be formed on the end members 12 and 13 can be shortened. Then, it can be easily manufactured by cold forging.

Next, as shown in FIG. 4, in the annular space 68, the partition plate 67 extends in the radial direction and is press-fitted into the slits 63 a, 62 a provided in the axial direction of the inner cylinder 63 and the outer cylinder 62. Thus, the inner cylinder 63 is held with respect to the outer cylinder 62. As a result, when the outer cylinder 62 is chucked, the inner cylinder 63 can be positioned, and the inner cylinder 63 and the outer cylinder 62 form the frictional pressure contact 66 in such a manner that both end members 64 and 65 share the central axis. It will be possible. The method of fixing the partition plate 67 to the inner cylinder 63 and the outer cylinder 62 is not limited to the method of press-fitting into the slits described above, and other methods such as welding 63b may be used. Furthermore, when generally used in addition to the present invention, the method of fixing the inner cylinder 63 and the outer cylinder 62 does not need to extend over the entire length in the axial direction as with the partition plate, and may be a partial holding member. The structure and the like of the partition plate are as described above.

As described above, in the cylindrical gas generator 1 having the above-described configuration, the entire body is divided into three parts, and the both end members 12 and 13 and the intermediate cylindrical portions 3 and 2 form the main body. The length of the cylindrical portion to be formed into 13 can be shortened, and both end members 12 and 13 can be easily manufactured by cold forging or the like. Moreover, since the partition plate 67 for holding the inner cylinder 2 against the outer cylinder 3 is provided in the intermediate cylindrical portions 3 and 2, the inner cylinder 2 can be positioned during chucking. As a result, friction welding is facilitated and a cylindrical gas generator suitable for mass production can be provided.

[0024]

[Effect of the device]

 In the cylindrical gas generator of the present invention, a partition plate having gas holes is provided in the annular space between the inner cylinder and the outer cylinder to act as an obstacle in the gas flow path, so that the slurry is close to the partition plate. There is a place where the gas easily accumulates, and at the same time, the gas flow stagnates and the flow velocity is reduced, so it becomes easier to capture the slag by the filter. Therefore, the collection rate of slag can be increased. As a result, the overall filter efficiency is improved, and the cylindrical gas generator can be made smaller and lighter.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a cylindrical gas generator of the present invention.

FIG. 2 is a cross-sectional view of a cylindrical gas generator of the present invention.

FIG. 3 is a view showing a partition plate of the present invention.

FIG. 4 is a cross-sectional view of the cylindrical gas generator of the present invention.

FIG. 5 is a cross-sectional view of a gas filter.

FIG. 6 is a sectional view of an airbag safety device.

FIG. 7 is a vertical cross-sectional view of a conventional cylindrical gas generator.

FIG. 8 is a cross-sectional view of a conventional cylindrical gas generator.

[Explanation of symbols]

 1 Cylindrical Gas Generator 2 Inner Cylinder 2a First Gas Hole 3 Outer Cylinder 3a Second Gas Hole 4 First Filter 5 Second Filter 6 Third Filter 7 Gas Generating Agent 11 Partition Plate 11a Third Gas Hole 12 Both Ends 13 Both end members 14 Annular space

Claims (1)

[Scope of utility model registration request] 1. An inner cylinder and an outer cylinder that share a central axis are integrated at both end members, a gas generating agent and the like are contained in the inner cylinder, and a filter is housed in an annular space between the inner cylinder and the outer cylinder. In the cylindrical gas generator, a first gas hole is provided in a predetermined azimuth angle of the inner cylinder, and a second gas hole is provided in an outer circumference of the outer cylinder having an azimuth angle different in phase from the predetermined azimuth angle. A cylindrical type characterized in that a partition plate having a third gas hole and extending in the radial direction to partition the annular space portion is provided on the way from the first gas hole to the second gas hole of the space portion. Gas generator.