A filter for a tubular pyrotechnic gas generator and a method for preparing the same

Abstract

The present invention relates to the technical field of automobile airbag gas generators, specifically a filter for a tubular pyrotechnic gas generator and a preparation method thereof, comprising a plain woven metal mesh and a forming structure. The plain woven metal mesh is a cylindrical structure with a hollow center. The forming structure is fixed to the end of the plain woven metal mesh. The plain woven metal mesh and the forming structure are fixed in a charge chamber. The forming structure is located on the side close to the exhaust hole. An airflow passage is formed inside the plain woven metal mesh. The airflow passage extends along the axial direction of the charge chamber toward the ignition tool assembly. Compared with the prior art, the present invention forms a stable airflow passage inside the plain woven metal mesh or a perforated metal thin material cylinder. Without the need to add components, the occurrence of airflow blockage during the detonation of the gas generator is prevented. The present invention has a simple structure and is easy to install, which reduces the component cost and manufacturing cost of the product. The stability and uniformity of the present invention are fully guaranteed.

Description

Technical Field

[0001] The invention relates to the technical field of automobile safety airbag gas generators, in particular to a filter for a tubular pyrotechnic gas generator and a preparation method thereof. Background Art

[0002] The automobile airbag module consists of a gas generator and an inflatable bag. When the car collides and sends an ignition signal, the gas generator will be instantly ignited and produce a large amount of gas. The large amount of gas generated by the combustion of the gas generating agent is discharged into the airbag through the exhaust holes distributed in a circle on the gas generator shell to inflate the airbag, thereby protecting the occupants from injury. Since the gas generator is the core component of the automobile airbag, as the popularity of automobile airbags continues to increase, the requirements for the performance, reliability and price of the gas generator are also getting higher and higher.

[0003] Automobile airbag modules are installed in different locations in the car to achieve different protection purposes, and the types of gas generators installed in these airbags are also different. For example, in order to prevent front collisions, driver-side airbags and passenger-side airbags require pancake-shaped pyrotechnic gas generators. For seat-mounted side airbags and curtain airbags that prevent side collisions, slender tubular gas generators are required.

[0004] Patent document JP 3129859 discloses a structure of a tubular pyrotechnic gas generator, including an ignition tool assembly, a charge chamber and a combustion chamber, a filter and an exhaust hole. Since the charge chamber and the combustion chamber are relatively slender, it is easy to cause airflow blockage after ignition from the end of the combustion chamber. For this reason, patent document JPA2008149837 discloses another structure of a tubular pyrotechnic gas generator: by arranging a spring at the center of the combustion chamber and the charge chamber, an airflow passage along the axial direction of the combustion chamber is formed in advance, so that when the gas generator is ignited, possible airflow blockage can be effectively prevented.

[0005] In several mass-produced tubular pyrotechnic gas generators currently on the market, a special airflow passage is formed by adding other parts at the central axis of the combustion chamber or near the combustion chamber tube wall to prevent the problem of airflow being blocked when the gas generator is ignited. However, in order to set up this special airflow passage, the number of parts needs to be increased, which makes the structure of the gas generator complicated and increases the manufacturing cost of the product.

[0006] Therefore, it is necessary to design a tubular pyrotechnic gas generator filter and a preparation method thereof, which can form a stable airflow passage without adding parts and has sufficient airflow cooling effect and the ability to collect solid residues in the airflow. Summary of the invention

[0007] The purpose of the present invention is to overcome the deficiencies of the prior art and to provide a tubular pyrotechnic gas generator filter and a preparation method thereof, which can form a stable airflow path without adding components and has sufficient airflow cooling effect and the ability to collect solid residues in the airflow.

[0008] In order to achieve the above-mentioned purpose, the present invention is a filter for a tubular pyrotechnic gas generator, comprising a plain woven metal mesh and a forming structure. The plain woven metal mesh is a cylindrical structure with a hollow middle portion. The forming structure is fixed to the end of the plain woven metal mesh. The plain woven metal mesh and the forming structure are fixed in a charge chamber. The forming structure is located on the side close to the exhaust hole. An air flow passage is formed inside the plain woven metal mesh. The air flow passage extends along the axial direction of the charge chamber toward the ignition device assembly.

[0009] The flat woven metal mesh is attached to the tube wall of the charge chamber, and the air flow passage is close to the tube wall of the charge chamber.

[0010] The flat woven metal mesh is provided with an inwardly contracted forming part, a distance exists between the forming part and the tube wall of the charge chamber, and the air flow passage is close to the center of the charge chamber, thus reducing the heat transfer between the forming part and the tube wall of the charge chamber.

[0011] The flat woven metal mesh can be replaced by a cylinder formed by winding a thin metal material with punching holes.

[0012] The forming structure is a crocheted metal mesh forming structure or a forming structure formed by pressing a metal wire assembly.

[0013] The preparation method of the filter for the tubular pyrotechnic gas generator is prepared according to the following steps: step 1, cutting the raw material of the plain woven metal mesh into the required shape, winding it into a cylindrical shape and fixing it by spot welding to form a cylindrical portion of the plain woven metal mesh; step 2, cutting the raw material of the crocheted metal mesh into crocheted metal mesh pieces of the required shape or preparing a required amount of metal wire aggregates; step 3, placing the cut crocheted metal mesh pieces or metal wire aggregates into the plain woven metal mesh cylinder, and applying a pressure of 5 to 50 kilograms to form a formed structure of the crocheted metal mesh or metal wire aggregate.

[0014] The method further comprises step 4 of applying pressure inward to the tube wall of the plain woven metal mesh so that the plain woven metal mesh covers the outside of the forming structure of the hook-woven metal mesh or the metal wire assembly and forms an inwardly contracted forming part.

[0015] The preparation is carried out according to the following steps: Step 1, cutting the punched metal thin material into the required shape, winding it into a cylinder and then fixing it by spot welding to form a punched metal thin material cylinder; Step 2, cutting the woven metal mesh raw material into woven metal mesh pieces of the required shape or preparing the required amount of metal wire aggregates; Step 3, placing the cut woven metal mesh pieces or metal wire aggregates into the punched metal thin material cylinder, and applying a pressure of 5 to 50 kilograms to form a formed structure of the woven metal mesh or metal wire aggregate.

[0016] The method also includes step 4, in which the wall of the metal thin material cylinder with punching holes is pressurized inwardly so that the metal thin material cylinder with punching holes is covered outside the forming structure of the crocheted metal mesh or metal wire assembly and forms an inwardly contracted forming part.

[0017] The inwardly contracted forming part is in a three-leaf shape or a four-leaf shape.

[0018] Compared with the prior art, the present invention designs a filter structure composed of a plain woven metal mesh or a metal thin material with punching holes and a forming structure, and forms a stable airflow passage inside the cylinder of the plain woven metal mesh or the metal thin material with punching holes. Without the need to add additional parts, the occurrence of airflow blockage during the detonation of the gas generator is prevented. The present invention has a simple structure and is easy to install, which reduces the parts cost and manufacturing cost of the product. The size and weight of the plain woven metal mesh or the metal thin material part with punching holes, the hooked metal mesh or the metal wire aggregate forming structure can be effectively controlled, and the stability and uniformity of the present invention are fully guaranteed. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 The structure of the present invention is schematically shown Figure 1 .

[0020] Figure 2 The structure of the present invention is schematically shown Figure 2 .

[0021] Figure 3 Schematic diagram of the air flow path of the present invention Figure 1 .

[0022] Figure 4 Schematic diagram of the air flow path of the present invention Figure 2 .

[0023] Figure 5 This is a schematic diagram of the present invention installed in a tubular pyrotechnic gas generator in Example 1.

[0024] Figure 6 This is a schematic diagram of the present invention installed in a tubular pyrotechnic gas generator in Example 2. DETAILED DESCRIPTION

[0025] The present invention will now be further described with reference to the accompanying drawings.

[0026] See also Figures 1 to 4 The present invention is a filter for a tubular pyrotechnic gas generator, comprising a plain woven metal mesh and a forming structure. The plain woven metal mesh 1 is a cylindrical structure with a hollow center. The forming structure 2 is fixed to the end of the plain woven metal mesh 1. The plain woven metal mesh 1 and the forming structure 2 are fixed in a charge chamber 3. The forming structure 2 is located on the side close to the exhaust hole 8. An air flow passage 5 is formed inside the plain woven metal mesh 1. The air flow passage 5 extends along the axial direction of the charge chamber 3 toward the ignition tool assembly 4.

[0027] The plain woven metal mesh 1 mainly serves as an airflow passage, and can also capture some solid residues and partially reduce the airflow temperature. The forming structure 2 mainly captures residues and reduces the airflow temperature due to its small pores and high density.

[0028] In the present invention, the plain woven metal mesh or the metal thin material cylinder with punching is formed by winding one or more layers of the plain woven metal mesh raw material or the metal thin material with punching. The metal thin material with punching can be a metal sheet with punching or a metal sheet with punching, and the amount of the plain woven metal mesh or the metal thin material with punching and the size of the cylinder after winding can be effectively controlled, so the stability and uniformity of the parameters such as the air permeability, the outer dimensions and the weight of the cylinder can be fully guaranteed. The weight and the size after forming of the forming structure 2 composed of the hooked metal mesh or the metal wire assembly can also be effectively controlled, so the stability and uniformity of the forming structure 2 composed of the hooked metal mesh or the metal wire assembly can also be fully guaranteed. The stability and uniformity of the present invention are fully guaranteed, so that it can also be guaranteed that the tubular pyrotechnic gas generator using the present invention has stable and consistent output characteristics.

[0029] Example 1, see Figure 3 and Figure 5 In this example, the plain woven metal mesh 1 or the metal thin material cylinder with punching holes is attached to the tube wall of the charging chamber 3, so the air flow passage 5 is close to the tube wall of the charging chamber 3.

[0030] This embodiment is prepared according to the following steps: Step 1, cutting the raw material of the plain woven metal mesh into the required shape, and winding it into a cylindrical shape and then fixing it by spot welding to form the cylindrical part of the plain woven metal mesh; Step 2, cutting the raw material of the hooked metal mesh into the hooked metal mesh pieces of the required shape or preparing the required amount of metal wire aggregates; Step 3, putting the cut hooked metal mesh pieces or metal wire aggregates into the cylinder of the plain woven metal mesh, and applying a pressure of 5 to 50 kilograms to form the forming structure of the hooked metal mesh or metal wire aggregate. During the forming process of the hooked metal mesh or metal wire aggregate, due to the large pressure applied, the forming structure of the hooked metal mesh or metal wire aggregate will expand outward in the radial direction, and the forming structure of the hooked metal mesh or metal wire aggregate will be in close contact with the inner surface of the plain woven metal mesh. Therefore, there is no need to use another method to fix between the plain woven metal mesh and the forming structure of the hooked metal mesh or metal wire aggregate.

[0031] This embodiment can also be prepared according to the following steps: Step 1, cutting the metal thin material with punching holes into the required shape, and then winding it into a cylindrical shape and fixing it by spot welding to form a metal thin material cylinder with punching holes; Step 2, cutting the raw material of the woven metal mesh into the woven metal mesh pieces of the required shape or preparing the required amount of metal wire aggregates; Step 3, putting the cut woven metal mesh pieces or metal wire aggregates into the metal thin material cylinder with punching holes, and applying a pressure of 5 to 50 kilograms to form a forming structure of the woven metal mesh or metal wire aggregate. During the forming process of the woven metal mesh or metal wire aggregate, due to the large pressure applied, the forming structure of the woven metal mesh or metal wire aggregate will expand outward in the radial direction, and the forming structure of the woven metal mesh or metal wire aggregate will be in close contact with the inner surface of the metal thin material cylinder with punching holes. Therefore, there is no need to use another method to fix between the metal thin material cylinder with punching holes and the forming structure of the woven metal mesh or metal wire aggregate.

[0032] The assembly process of this embodiment is as follows: 1. Paste the sealing metal sheet 7 at the bottom of the charging chamber 3; 2. Install the filter consisting of a plain woven metal mesh 1 or a punched metal thin material cylinder and a forming structure 2 into the charging chamber 3; 3. Fill the gas-generating powder in the container of the charging chamber 3; 4. Insert the ignition tool assembly 4 with an O-ring sealing rubber ring 6 into the charging chamber 3 and fix it by closing the opening.

[0033] Since the plain woven metal mesh 1 or the metal thin material cylinder with punching holes in the embodiment 1 also serves as an airflow passage, no additional parts are needed to form a dedicated airflow passage. Therefore, the tubular pyrotechnic gas generator using the filter of the present invention has fewer parts, a simple structure, and is easy to assemble, thereby achieving a lower price for the tubular pyrotechnic gas generator.

[0034] Example 2, see Figure 4 and Figure 6 In this example, the plain woven metal mesh 1 or the perforated metal thin material cylinder is provided with an inwardly contracted forming portion 11, and there is a distance between the forming portion 11 and the tube wall of the charging chamber 3. The air flow passage 5 is located at the central axis of the charging chamber 3, which reduces the heat transfer between the gas passage portion 11 and the tube wall of the charging chamber 3.

[0035] The preparation method of this embodiment adds step 4 on the basis of embodiment 1, which pressurizes the tube wall of the plain woven metal mesh inwardly so that the plain woven metal mesh is covered outside the forming structure of the hook-woven metal mesh or the metal wire assembly, and forms an inwardly contracted forming part.

[0036] Step 4 may also be: pressurizing the wall of the metal thin material cylinder with holes inwardly so that the metal thin material cylinder with holes is covered outside the forming structure of the crocheted metal mesh or metal wire assembly and forms an inwardly contracted forming part.

[0037] The inwardly contracted shaped portion is in a three-leaf or four-leaf shape.

[0038] The assembly process of this embodiment is exactly the same as that of embodiment 1.

[0039] During the operation of the tubular pyrotechnic gas generator, the central part of the filter will also become very hot because it will also capture a large amount of high-temperature residues and absorb a large amount of heat from the airflow. Compared with Example 1, in this embodiment, since the central part of the filter that becomes very hot is a certain distance away from the tube wall of the charge chamber 3, the heat transfer between the forming part 11 and the tube wall of the charge chamber 3 is reduced, so the heat transferred from the central part of the filter to the tube wall of the tubular pyrotechnic gas generator is less. Therefore, the temperature of the outer surface of the tubular pyrotechnic gas generator using this embodiment will be lower, which is very beneficial for the design of the subsequent airbag module.

[0040] In summary, in various embodiments of the present invention, by using the filter of the present invention, a stable and reliable gas channel can be formed, thereby effectively preventing the occurrence of airflow blockage during the detonation process of the gas generator without adding parts. The present invention has a simple structure and is easy to install, which reduces the parts cost and manufacturing cost of the product, thereby achieving a lower product price. The size and weight of the flat woven metal mesh or the thin metal material part with punching holes, the hooked metal mesh or the metal wire aggregate forming structure can be effectively controlled, the stability and uniformity of the present invention are fully guaranteed, and the stability and consistency of the pressure output performance of the tubular pyrotechnic gas generator using the filter of the present invention will also be fully guaranteed.

Claims

1. A method for preparing a filter for a tubular pyrotechnic gas generator, characterized in that: The filter for a tubular pyrotechnic gas generator comprises a plain woven metal mesh and a forming structure. The plain woven metal mesh (1) is a cylindrical structure with a hollow center. The forming structure (2) is fixed to the end of the plain woven metal mesh (1). The plain woven metal mesh (1) and the forming structure (2) are fixed in a charge chamber (3). The forming structure (2) is located on a side close to an exhaust hole (8). An air flow passage (5) is formed inside the plain woven metal mesh (1). The air flow passage (5) extends along the axial direction of the charge chamber (3) toward an ignition tool assembly (4). , prepared according to the following steps: Step 1, cutting the raw material of the plain woven metal mesh into the required shape, winding it into a cylindrical shape and then fixing it by spot welding to form the cylindrical part of the plain woven metal mesh; Step 2, cutting the raw material of the woven metal mesh into woven metal mesh pieces of the required shape or preparing the required amount of metal wire aggregates; Step 3, loading the cut woven metal mesh pieces or metal wire aggregates into the plain woven metal mesh cylinder, and applying a pressure of 5 to 50 kilograms to form a formed structure of the woven metal mesh or metal wire aggregate.

2. The method for preparing a filter for a tubular pyrotechnic gas generator according to claim 1, characterized in that: The method further comprises step 4 of applying pressure inward to the tube wall of the plain woven metal mesh so that the plain woven metal mesh covers the outside of the forming structure of the hook-woven metal mesh or the metal wire assembly and forms an inwardly contracted forming part.

3. A method for preparing a filter for a tubular pyrotechnic gas generator, characterized in that: The filter for a tubular pyrotechnic gas generator comprises a punched metal thin material and a forming structure. The punched metal thin material is a cylindrical structure with a hollow center. The forming structure (2) is fixed to the end of the punched metal thin material. The punched metal thin material and the forming structure (2) are fixed in a charge chamber (3). The forming structure (2) is located on a side close to an exhaust hole (8). An air flow passage (5) is formed inside the punched metal thin material. The air flow passage (5) extends along the axial direction of the charge chamber (3) toward an ignition tool assembly (4). , prepared according to the following steps: Step 1, cutting the punched metal thin material into the required shape, winding it into a cylinder and then fixing it by spot welding to form a punched metal thin material cylinder; Step 2, cutting the crocheted metal mesh raw material into crocheted metal mesh pieces of the required shape or preparing the required amount of metal wire aggregates; Step 3, putting the cut crocheted metal mesh pieces or metal wire aggregates into the punched metal thin material cylinder, and applying a pressure of 5 to 50 kilograms to form a formed structure of the crocheted metal mesh or metal wire aggregate.

4. The method for preparing a filter for a tubular pyrotechnic gas generator according to claim 3, characterized in that: The method also includes step 4, in which the wall of the metal thin material cylinder with punching holes is pressurized inwardly so that the metal thin material cylinder with punching holes is covered outside the forming structure of the crocheted metal mesh or metal wire assembly and forms an inwardly contracted forming part.

5. A method for preparing a filter for a tubular pyrotechnic gas generator according to claim 2 or 4, characterized in that: The inwardly contracted forming portion is in a three-leaf shape or a four-leaf shape.

6. A method for preparing a filter for a tubular pyrotechnic gas generator according to claim 1 or 3, characterized in that: The plain woven metal mesh (1) or the metal thin material with punching holes is attached to the tube wall of the charge chamber (3), and the air flow passage (5) is close to the tube wall of the charge chamber (3).

7. A method for preparing a filter for a tubular pyrotechnic gas generator according to claim 1 or 3, wherein the plain woven metal mesh (1) or the metal thin material with punching holes is provided with a forming portion (11) that shrinks inwardly, there is a distance between the forming portion (11) and the wall of the charge chamber (3), and the air flow passage (5) is close to the center of the charge chamber (3), thereby reducing the heat transfer between the forming portion (11) and the wall of the charge chamber (3).

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