JP2009533221A - Wire wound wire filter - Google Patents

Abstract

A cylindrically wound wire filter with an inner bore suitable for use with an airbag inflator has at least two different outer diameters and / or at least two different inner diameters. The wires in adjacent layers are joined together by adhesive or brazing, or have a sheet-like material such as ceramic filter paper between the wires.
[Selection] Figure 6

Description

  The present invention relates to a filter element and manufacturing the filter element by winding a wire around a mandrel.

  Filters have long been manufactured by spirally wrapping a piece of elongated material, such as paper or wire, into a mold for making the filter. Patent Document 1 describes an intake filter for an internal combustion engine that is manufactured by spirally winding a gimp wire. As described in U.S. Pat. No. 6,057,049, spirally wound polymer fibers are used to produce various filtering or separation devices.

  In the field of gas generators, such as those used to inflate airbags for passenger cars, filters are used to control and cool the hot explosion products produced by the gas generator. Patent Document 3 describes a hollow cylindrical core in which various material layers including a filter layer, which are later cut into a plurality of filters of a desired size, are spirally wound. As in Patent Document 4 and Patent Document 5, in order to manufacture an airbag inflator filter, ceramic fibers have been wound around a core in a spiral shape. With respect to wire filters, Patent Document 6 has a copper-plated iron wire knitted together and then heat treated between the melting point of copper and the sintering temperature of copper to bond the iron wires together where the iron wires intersect. The filter that is to be described. Patent Document 7 describes a filter having two layers, in which a wire is spirally wound. Here, the pitch angle of the first layer overlying itself in the radial direction is symmetric, and the second layer has finer filtration by using thinner wires.

  A number of winding machines are known, ranging from machines that wind wires on prestressed pipes with metric diameters to machines that bob bobbins or tubes with centimeter diameters. It is also known to provide computer control for such machines.

US Pat. No. 2,122,582 US Pat. No. 4,048,074 US Pat. No. 5,230,726 US Pat. No. 5,702,494 US Pat. No. 5,908,481 International Application Publication No. WO05 / 065811 International Application Publication No. WO05 / 065999 US Pat. No. 6,277,166 US Pat. No. 4,890,860 US Pat. No. 6,913,059

  There is a need for a simpler method of securing the winding wire to the winding wire itself, and a filter having an outer shape or geometric shape other than cylindrical.

  In view of the above, the present invention provides a radial intermediate disposed between a wound wire filter having a geometric shape other than a right prism, an enhanced winding file, and an adjacent wire layer. A wound wire filter having another material provided as part.

  The present invention provides a cylindrical wound wire filter having an inner bore suitable for use with an airbag inflator. The cylindrical wound wire filter has at least two different outer diameters and / or at least two different inner diameters. The plurality of wires in adjacent layers are joined together by brazing or have a sheet-like material such as ceramic filter paper between the plurality of wires. A wax material is an example of an auxiliary agent. The adjuvant may be an adhesive or an elongated piece of knitted or non-woven material such as ceramic filter paper supplied along the wire.

  In general, the present invention relates to a first inner diameter, a first outer diameter, at least one second (different) inner diameter (different from the first inner diameter) or at least one second (different) outer diameter. A wire wound wire filter having a different diameter than the first outer diameter.

  As described in the background art, winding machines controlled by a computer are known. In one embodiment, the present invention uses computer control in a novel manner to create a filter having a geometric shape other than a right prism. As shown in FIG. 1, a typical winding machine has a mandrel 1 and a source 2 of wire 3 in the present invention that is wound on the mandrel and of an undefined length. For the purposes of the present invention, the wire is preferably a flat wire, although a circular cross section, an elliptical cross section, or any other cross section can be used. The mandrel is preferably a prefabricated mandrel such as a drill chuck. In these machines controlled by a computer, the source position L is controlled with respect to the rotational speed R of the mandrel. The angle α (helical angle) between the wire and the mandrel centerline (rotation axis) is usually kept constant and the source moves regularly in one direction, ie between the ends of the mandrel (or the wire Moves back and forth regularly (over any length desired to form the part). The dwell time is usually zero at both ends. That is, when the source reaches one end of the mandrel, it immediately returns to the other end.

  In the present invention, the angle α is varied and the movement of the source is changed to achieve the desired geometry. By simple programming or by adjusting existing computer controls, the helix angle and dwell time are adjusted to form geometric shapes other than simple right prisms. As an alternative to the spiral angle, the number of winds can be specified. The “wind number” is the number of windings per linear length parallel to the rotation axis of the mandrel. Since the circumference changes as the wire is wound, if the helix angle is fixed, the number of winds changes as the device grows. Similarly, if the number of winds is fixed, the helix angle increases as the device gets larger Will change. The dwell time at a particular axial length can be varied to change the thickness of the winding layer over that length. This device is made relatively easily from commercially available parts or by modifying a conventional wire winding machine.

  FIG. 2 shows a dumbbell-shaped wound wire filter 10 having a central cylinder 12 and a plurality of disk-shaped ends 13 each having a larger radius than the central cylinder. To make such a device, the central cylinder is wound over the entire length of the filter, then one of the dumbbell ends is wound, and then moved to the other end at this end. Program the computer to do the winding. When the moving speed is sufficiently slow, the wire on the outer periphery of the first dumbbell is wound around the central portion first, and is almost indistinguishable from the central portion. In this way, the filter shown in FIG. 2 has a geometric shape other than a simple right prism. To be precise, the device has two outer diameters: an outer diameter at the center and an outer diameter at both ends of the dumbbell, and a single inner diameter.

  These filters can be used for airbag inflators, such as wire mesh filters, as described in US Pat. In the patent of Patent Document 8, a wire mesh tube is compressed in a mold to form an annular filter in which a plurality of ribs extend in the axial direction on the outside. Using the present invention, effectively adding a larger disk (s) between the outermost disks (ie, two different outer diameters) effectively, such as the dumbbell design of FIG. A filter having ribs extending in the lateral direction can be produced.

  In some airbag inflators, the charge is supplied in a short, rigid tube, both ends of the tube are sealed, and there are multiple openings on the circumference of the tube to escape gas is doing. Using the present invention, the sacrificial band can be placed on a mandrel and a filter wound in the desired geometric shape. The device is then removed from the mandrel and the band to be removed. The band can be a polymer such as neoprene that is mechanically or manually removed, or polystyrene that is burned off or chemically dissolved, or a water soluble polymer. As shown in FIG. 3, the resulting filter 31 has a hole 32 and a band 33 of sacrificial material that forces a void 35 to be formed in the wound material. The filter shown in FIG. 3 has a single outer diameter and a plurality of inner diameters. Surprisingly, it has been found that if the wire is wound under tension, no noticeable deformation of the voids occurs when the sacrificial material is removed. In use, the void functions as a manifold for explosive gases. Also shown in FIG. 3 is a continuous (axial) outer layer 37 formed by a series of continuous windings. That is, the outer layer has a straight cylindrical wire filter as a tube. With this continuous layer, explosive gases exit the filter axially.

  FIG. 4 shows the changes that can be made to the wire before winding. In one embodiment, the wire passes through a set of crimping rolls 42 so that the wound wire becomes corrugated. If the filter is placed in a tubular structure, the corrugated wire is preferably placed on the outside. Since the corrugated wire is more compressible (in the radial direction) than the non-corrugated wire of the bulk filter, the filter with the corrugated wire on the outside can be more easily pressure fitted into the cylinder. Similarly, a corrugated layer can be formed immediately adjacent to the mandrel to allow the annular structure (eg, the above-described airbag charge) to be pushed into the pores of the filter.

  Another embodiment shown in FIG. 4 is the application of an adjuvant to the surface of the wire prior to winding. For example, a coater 44 adjacent to the wire is used to apply a paintable or sprayable fluid from the reservoir 46 to the wire. The applicator can be a brush or a spray nozzle. Adjuvants need not be used with corrugation and can be applied to one or both sides of the wire. The auxiliary agent can be an adhesive that adds shear strength to the winding structure. The adjuvant can be a paste used for brazing. The wrapped filter can be sintered to provide a diffusion bond where the wires intersect. By using a brazing aid, such as copper powder (eg, 300 mesh) (eg, propylene glycol) in vehicles, a stronger bond can be achieved. The wires are brazed and a stronger bond is formed between the intersecting wires. It may be desirable to hold the filter on the mandrel during sintering or other heat treatment. In this case, the mandrel can be coated with a non-reactive material (eg, SiN, BN) that allows the heat treated filter to be easily removed from the mandrel after heat treatment.

  Similar to applying an adjuvant to the wire, a strip of sheet-like material can be fed along the wire during winding. Suitable sheet-like materials include woven metal or glass fibers, non-woven mats (eg, glass fibers or carbon fibers, or ceramic filter paper (eg, US Pat. )), And stainless steel microfibers (for example, mesh form). The width of the filter paper is preferably wider than the width of the wire. By using an unwoven strip or filter paper, relatively finer particles can be filtered. Depending on the metal used in the wire (at least as strong as SS309), heat-resistant stainless steel is preferred for the present invention), a thermally decomposable polymer fiber or strip of polymer can be supplied with the wire, and the filter During the heat treatment, the strip can be pyrolyzed to ceramic or carbon.

  5-7 show a wound wire filter device having a flat exterior where the wires are wound side by side, an interior where the wires are spirally wound, and a smaller inner diameter. FIG. 5 shows a winding having an innermost diameter 501 around which wires are wound side by side to form a flat, i.e., uneven surface, and an intermediate portion 503 in which the winding of the wire changes in a spiral shape. It is an enlarged view of a wire filter. The innermost surface terminates in a shelf 505 that effectively forms an internal flange that separates the smaller and larger inner diameters of the device. FIG. 6 shows a similar device, in which the outer surface 601 of the filter is flat (coiled side by side) and the windings are small as seen on the inner surface of the larger diameter. Terminate at shelf 605 (603). As in FIG. 5, the smaller diameter inner diameter terminates in another shelf 607. FIG. 7 is another perspective view of a similar device having a flat outer surface 701 overlying a spirally wound interior 703. The device has both a larger diameter ID (ID) at 703 and a smaller diameter ID that terminates at shelf 705. From the apparatus seen in FIGS. 5-7, the winding filter can be made to have multiple inner and / or outer diameters, and to have flat windings (ie, side-by-side windings) It can be seen that the innermost surface and / or the outermost surface can be made more porous by a spiral winding.

  In another embodiment, the expanded metal sleeve can be placed on the inner and / or outer diameter. The axial strength of the filter can be improved by directing the expanded metal diamond shaped aperture along the filter axis. In addition, if the sleeve is thicker than the wire used for the winding, the sleeve functions as a heat sink, protecting the smaller wires. The expanded metal sleeve can be made from carbon steel, stainless steel, or any other metallic material. The sleeve can be placed when the device is sintered so that it will fuse with any wire in contact.

  In another embodiment, the winding of the wire to the mandrel can be stopped at one end of the unfinished winding and the insert is placed over the existing winding and then continues with the winding, The insert is effectively encased between the inner winding and the relatively outer winding. This operation can be performed multiple times and can include a sleeve with a porous interior, such as the expanded metal sleeve described above. The insert may take the form of a perforated sheet (metal or polymer comprising a fabric such as a net or knitted fabric), a pre-formed tube (eg expanded metal tube), a mesh (plastic or metal, preferably knitted), or any combination. be able to.

  In the embodiments described above, the filter preferably has an inner diameter of about 1 inch to 3 inches (2.5 cm to 7.5 cm) and a length of about 1 inch to 2 inches (20 cm to 50 cm), which are It is suitable for installation in the steering wheel of a vehicle as a part of an airbag on the driver's seat side. The filter for the airbag safety device on the passenger side is usually much longer (about 12 cm to 18 cm) and has a smaller diameter (about 15 cm to 40 cm). Airbag curtain devices that protect against contact with the side windows have a much smaller inner diameter (5 mm to 20 mm) and length (about 20 mm to 30 mm). The thickness of the filter depends on the specific application and the charge used. Front (driver and passenger) airbags typically use explosive materials for charge, while side (curtain) airbags charge charge that is ignited during a collision or explode gas during a collision. Use one of the built-in gas cylinders to release.

  Since the front airbag on the passenger side of the vehicle is usually much larger than the front airbag on the driver side, more gas needs to be generated. The front airbag device on the driver's side can contain a single charge, while the front airbag on the passenger side can detect up to five equivalent charges (including passenger weight) including different sizes of charge. Thus, not all of these charges are ignited, as in “smart” airbag technology for the required explosive power. Due to the internal design of the vehicle, the front airbag on the passenger side must cover a dashboard part that is much larger than the front airbag on the driver side (basically protecting the driver from the steering wheel) . Therefore, as mentioned above, these devices and thus the filters are much longer.

  In another embodiment, the present invention provides a filter that is particularly useful for a front airbag on the passenger side. Here, the wire is wound around a hollow core having a number of openings. The core can be any material that resists explosion and provides filtering. A woven or knitted wire mesh can be used as the core. The sheet or net of woven metal wire is rolled into a tube or cylinder, and the abutting ends are welded. Wire mesh is typically knitted as a tube, and where the woven wires overlap, they can be spot welded to provide wire mesh integrity. The wire mesh can then be cut to the desired tube length. Another alternative is an expanded metal sheet. Like a woven sheet, the expanded metal sheet is cut to an appropriate size and its abutting edges are welded to provide a cylinder. Since the explosion is essentially isotropic and the wire is wound around the core, the abutting edge is preferred over the overlapping edge. As shown in FIG. 8, the expanded metal sheet is rolled into a cylinder and its abutting edges are welded to provide a core 801. Each end 803 of the core is preferably flared. The core is then placed on the mandrel and a wire 805 is wrapped around the core to provide a filter. As in the filter described above, the end of the wire is preferably spot welded to the winding and then cut to ensure that the wire does not entangle. As described above, the windings can be made to provide various patterns or structures of windings. The core is preferably made of stainless steel and has a thickness of about 0.1 mm to about 1.0 mm (thickness is about 0.5 mm in the figure), with about 5% to 50% being a gap. (Ie, many openings occupy some proportion of the area on one side).

  9A is a side view of the filter, FIG. 9B is a plan view of the filter, and FIG. 9C is a perspective view of the filter. Here, the inner surface 901 is relatively flat and the outer surface 903 is made using a relatively large angle, thereby providing a pattern in which the spiral winding is relatively open. Compared to the shelves shown in FIG. 6, the shelves 905 are more clearly defined due to the winding pattern shown in these figures, and therefore the housing in which the filter is used. Form a flange with good tolerance to the connection.

  The above description is intended to be illustrative and not limiting. Various changes, modifications and additions will become apparent to those skilled in the art upon reading this specification. Such alterations, modifications, and additions are intended to be within the scope and spirit of the invention as defined by the appended claims.

It is a figure which shows a winding apparatus. It is a figure which shows the winding wire filter of dumbbell shape. It is sectional drawing of the filter which has a some internal diameter and one sacrificial member. FIG. 2 shows the apparatus of FIG. 1 with a set of crimping rolls and an applicator for paintable or sprayable auxiliary material. FIG. 4 shows a wound wire filter having a flat exterior, a spirally wound interior, and two or more inner diameters. FIG. 4 shows a wound wire filter having a flat exterior, a spirally wound interior, and two or more inner diameters. FIG. 4 shows a wound wire filter having a flat exterior, a spirally wound interior, and two or more inner diameters. It is a figure which shows the winding wire filter which has an expanded metal core. 1 is a side view of a filter design made in accordance with the present invention. FIG. 1 is a plan view of a filter design made in accordance with the present invention. FIG. 1 is a perspective view of a filter design made in accordance with the present invention. FIG.

Claims (18)

  A wound wire filter, wherein the wound wire filter is made from a single continuous wire and has a first inner diameter, a first outer diameter, and a second inner diameter that is different from the first inner diameter. And at least one of a second outer diameter different from the first outer diameter.   The wound wire filter according to claim 1, comprising two second outer diameters.   A wire wound wire filter, wherein a plurality of wires in adjacent layers are joined to each other.   4. The wound wire filter according to claim 3, wherein the plurality of wires are joined by brazing.   4. The wound wire filter according to claim 3, wherein the plurality of wires are bonded together by an adhesive.   A wound wire filter, wherein at least a portion of the winding includes an strip of sheet material that is adjacent to the wire over at least a portion of the winding wire. Winding wire filter.   The winding wire filter according to claim 6, wherein the sheet-like material is a knitted metal.   7. The wound wire filter according to claim 6, wherein the sheet material is ceramic filter paper.   The wound wire filter according to claim 1, further comprising a continuous outer layer including the first inner diameter and the second inner diameter. A method for producing a filter comprising:
Winding a wire around a mandrel, creating an annular device having an innermost diameter and an outermost diameter; winding the wire around the mandrel; Changing, wherein the changing is effective to produce a filter having at least two inner diameters or at least two outer diameters, a helical angle of the wound wire, a dwell, a position, and To change the
A method comprising the steps of:   11. The method of claim 10, wherein changing the helix angle is effective to provide a flat surface on or inside the filter. The method of further comprising.   11. The method of claim 10, further comprising applying a wax material to the wire prior to winding.   11. The method of claim 10, further comprising winding the wire adjacent to a sheet material. A wire wound wire filter,
A hollow cylindrical core having a number of openings;
A single continuous wire wound around the core along the length of the core;
A wire-wound filter comprising:   15. The wound wire filter according to claim 14, wherein the core is an expanded metal sheet that is rounded into a cylinder and welded at an abutting edge.   The winding wire filter according to claim 14, wherein an end of the core is spread outward in a radial direction.   The wound wire filter according to claim 14, wherein the hollow cylindrical core is disposed between an inner winding and an outer winding.   15. The wound wire filter according to claim 14, wherein the hollow cylindrical core is a mesh or a fabric made of metal or plastic.

Images