Error-free metal fastening material feedthrough

Abstract

To provide a metal fixing material feedthrough with a conductor excellent in allowing more reliable assembly when an end product is pushed onto or into a connector.SOLUTION: A metal fixing material feedthrough for igniters of airbags and / or seatbelt pretensioners includes at least one metal pin fused into a glass or a glass-ceramic fixing material in a through-opening of a base body, the metal being present in a post-heated state, with an interface between the fixing material and the metal pin and an additional interface between the fixing material and an inner surface of the through-opening of the base body. The at least one metal pin, at least in its core region, comprises a special steel, preferably a chromium-containing special steel, the special steel having a prescribed thermal expansion coefficient αmetal pin.SELECTED DRAWING: Figure 1a

Description

[Technical Field]

[0001] The present invention relates to a metallic fastener feedthrough, in particular for devices that can be exposed to high pressures, preferably for personal protection devices such as igniters for airbags or seat belt pretensioners, which has at least one metal pin fused into the fastener material, preferably a glass or glass ceramic material. [Background technology]

[0002] Metal fastener feedthroughs are known in the prior art in a variety of configurations.

[0003] Metal fastener feedthroughs involve the vacuum-tight fusion of fastener materials, particularly glass, glass ceramic, or plastic, with metal, where the metal acts as an electrical conductor.

[0004] Representative examples include U.S. Pat. No. 5,345,872 and U.S. Pat. No. 3,274,937. Feedthroughs of this type are widely used in electronics and electrical engineering. The material used for the fusion, particularly glass, functions as an insulator in this case. Typical metal fastening material feedthroughs are designed so that a metallic inner conductor is attached to a glass material, which is fused to an outer metal part within a so-called base, which is formed from a ring-shaped or plate-shaped element.

[0005] A suitable application of this type of metallic fastener feedthrough is, for example, an ignition device. Such ignition devices are used, inter alia, for automobile airbags or seatbelt pretensioners. In this case, the metallic fastener feedthrough is a component of the ignition device. In addition to the metallic fastener feedthrough, the entire ignition device includes an ignition bridge, an explosive charge, and a metal cover tightly enclosing the ignition mechanism. The feedthrough can guide one, two, or more metal pins through it. In a particularly preferred embodiment with a metallic pin, the housing is connected to ground. In the preferred two-pole configuration, the ground is located on one of the pins.

[0006] US Patent Application Publication Nos. 2006 / 0222881, 2004 / 0216631, EP 1455160, 2007 / 0187934, and 1813906 disclose metal fastener feedthroughs, particularly for igniters of airbags or seatbelt pretensioners, characterized in that a through-hole for a metal pin is punched out of a base material. According to US Patent Application Publication No. 2007 / 0187934, the base material is produced by punching an opening through the entire thickness of the base material D from a strip material having a thickness in the range of 1 mm to 5 mm, preferably 1.5 mm to 3.5 mm, particularly 1.8 mm to 3.0 mm, and very particularly preferably 2.0 mm to 2.6 mm, by a stamping process.

[0007] The substrate is also commonly called a header.

[0008] In the feed-through known from WO 2012 / 110242, a substrate, inside which conductors are glass-sealed, is hermetically attached in a casing by welding, brazing, press-fitting, crimping or shrink-fitting. The casing parts and / or the substrate, preferably the substantially ring-shaped substrate, in WO 2012 / 110242 comprise as materials metals, in particular light metals, such as titanium, titanium alloys, magnesium, magnesium alloys, aluminum alloys, aluminum, AlSiC, but also steel, stainless steel or special steel.

[0009] The metal pins in the fixing material are inserted into the through-holes punched in the base over the entire thickness D of the base within the above range, in particular glass-sealed. The glass sealing is performed by first fusing the metal pins into the fixing material, e.g., glass plugs. The metal pins are then inserted into the through-holes together with the glass material, and the metal pins, glass material, and base are heated so that after cooling, the metal, preferably the metal of the base, shrinks onto the fixing material, e.g., glass plugs.

[0010] The expansion coefficient of the substrate is greater than that of the fastening material so that after cooling a compression glass-to-metal seal, particularly a gas-tight compression glass-to-metal seal, is formed.

[0011] In this application, airtightness means that the helium leakage is 1×10 -8 This is to be understood as being less than mbar l / sec.

[0012] To produce a continuous compression glass-to-metal seal that remains sealed in an operational state even after cooling and subsequent thermal cycling, the prior art, particularly in igniters for personal protective devices such as airbags and / or seatbelt pretensioners, assumes that the thermal expansion coefficients of the materials involved must have a predetermined ratio to one another. Because a compression glass-to-metal seal requires a shrink-fitting substrate on a glass material, also known as a glass body, the thermal expansion coefficient of the substrate must be greater than that of the glass material. Since the glass-sealed metal pin must not be dislodged from the glass material upon cooling, known measures require that the metal pin also have a thermal expansion coefficient smaller than that of the glass material. Therefore, when special steel is used as the substrate material in a personal protective device igniter, a metal pin made of nickel-iron or a nickel-iron alloy is typically sealed into the glass material.

[0013] Furthermore, in the feedthrough with two or more pins according to US 2007 / 0187934, the through holes are eccentrically arranged.

[0014] The stamping of substrates from sheet metal material according to US Patent Application Publication No. 2007 / 0187934 has drawbacks, one of which is that when stamping substrates from strip material, e.g., sheet metal, a certain percentage of material waste is generated.

[0015] DE 10 2010 045 624 A1 proposes producing a base body from wire material by cold forming and providing the base body with open areas, so that through holes can also be punched out of base bodies produced by cold forming.

[0016] DE 10 2006 056 077 A1 shows a pyrotechnic protection device, in particular for airbags or seat belt pretensioners, which has a through-hole in a base body, which is punched into the base body.

[0017] Further references to metal fastener feedthroughs are, for example, EP 1 491 848 A, EP 1 455 160 A, EP 1 813 906 A, EP 2 431 703 A or DE 10 2006 004 036 A1.

[0018] In particular, in metal fastener feedthroughs with two metal pins, the through-hole for mounting at least one of the metal pins is often eccentrically positioned, which can be a drawback in efficient mass production.

[0019] All of the above applications relating to metal fastener feed-throughs do not disclose pin materials that allow for reliable post-processing, e.g., assembly, especially after the metal pin has been glass-sealed in the glass material. The pin materials disclosed in WO 2012 / 110245, in particular NiFe, tend to bend, e.g., when inserted into a connector, during efficient mass production in automated manufacturing equipment and / or during further processing of the metal fastener feed-through, e.g., for an igniter, and / or assembly of the final product, and in extreme cases may break, which may result, e.g., in undesirable defective products. Summary of the Invention [Problem to be solved by the invention]

[0020] The object of the present invention is therefore to provide a metallic fastening material feedthrough with a conductor which avoids the disadvantages of the prior art and which is superior in that it can be produced in efficient mass production with a lower defect rate and / or can be assembled more reliably, for example when inserting the final product onto or into a connector. [Means for solving the problem]

[0021] According to the present invention, this problem is solved by a metal fastener feed-through with at least one metal pin, which consists, at least in its core region, of special steel according to standard EN 10020, and which is selected so that the metal pin, converted to standard dimensions of a metal pin diameter of 1.00±0.03 mm and a metal pin length of 11.68±0.2 mm, has a maximum elastic deflection of less than 0.13 mm, preferably less than 0.15 mm, more preferably less than 0.18 mm, in particular less than 0.20 mm, and very particularly preferably less than 0.21 mm. Most preferably, the maximum elastic deflection is in the range of 0.01 to 0.26 mm.

[0022] By elastic deflection, in the context of the present invention, is meant a deflection of the metal pin in which, when the mechanical load is removed, the metal pin returns to its original shape at least approximately again, without at least approximately any plastic deformation occurring, or in other words, the material of the metal pin is in the range of elastic deformation in the above-mentioned load range.

[0023] Metal pin length measures the protrusion of the metal pin from the underside of the glass seal, and therefore is independent of the length of the glass seal and / or the thickness of the header.

[0024] According to the present invention, the metal pin is fused into the through-hole of the substrate within the glass or glass ceramic material. During the glass sealing process, the metal pin is typically heated to a temperature of 600°C or higher, particularly 650°C or higher. The metal pin is then cooled again. As a result, the special steel of the metal pin is in a cooled state after the glass sealing process, which is generally referred to as an annealed state. The material properties of annealed special steel are significantly different from those of the unprocessed, i.e., unannealed, state.

[0025] The metal pins may exist as solid material or as coated solid material. In the case of coated metal pins, the core region of the metal pin is said to be solid material, i.e., the special steel material surrounded by the coating.

[0026] The present invention has the advantage that stainless steel pins, especially in the annealed state, are slightly flexible. This means that a greater mechanical load is required to plastically deform the stainless steel pin than is the case with conventionally used nickel-iron pins. Or, in other words, when a mechanical load below plastic deformation is applied, the stainless steel pin remains elastically deformable. This particularly improves the manufacturing process, since the possibility of deformation of the stainless steel pins on the production line is reduced. Similarly, more accurate tool positioning is possible, for example, during post-processing, such as coating or end grinding. It is also easier to insert unbent metal pins, i.e., pins that do not deviate from the target dimensions, into connectors, etc.

[0027] It is particularly advantageous if the special steel is selected so that the pin exhibits a maximum displacement of 0.21 mm, i.e. a displacement of less than 0.21 mm, during a standard load test in the range of 3 N to 4 N. In the case of such a small displacement, only an elastic deflection or deformation of the pin occurs, so that the pin returns to its starting position again.

[0028] For this purpose, the standard load test is to apply the above mechanical load perpendicular to the pin axis to a metal pin with dimensions of 1.00±0.03 mm and a metal pin length of 11.68±0.02 mm, and to measure the limit value W at which the limit of elastic bending is reached. max If the metal pin has other dimensions, a corresponding metal pin must be manufactured with the dimensions of the standard load test or the displacement must be calculated accordingly.

[0029] It is particularly preferred if the metal pins according to the invention are selected so that a mechanical load of 0.25% (strain) of at least one metal pin corresponds to a stress of more than 450 MPa, preferably more than 480 MPa or more than 500 MPa, particularly preferably between 450 MPa and 700 MPa. Higher stresses result in lower flexibility, i.e., a higher boundary for plastic deformation. However, these ranges are particularly preferred because materials with high stresses are difficult to reprocess, especially grind. These ranges are higher for annealed metal pins made of special steel than for annealed metal pins made of nickel iron, as known from the prior art.

[0030] Surprisingly, when special steel is used as the pin material, it has been confirmed that the removal force of the metal pin from the glass material of the through hole is higher than 250 N, particularly 250 N to 400 N, and preferably 300 N to 380 N. This is presumably because the glass-sealed, and therefore annealed, special steel metal pin is hard enough to better resist the pressure of the compression-type glass-to-metal seal. In other words, when the substrate contracts on the glass body in the through hole during cooling, as described above, pressure is applied to the metal pin through the glass body. If the metal pin is soft, it may succumb to this pressure, and the clamping action on the glass body may be weaker than with a harder metal pin. In this case, clamping action is an important aspect regarding the removal force.

[0031] In a preferred embodiment, a stainless steel metal pin is glass sealed into a substrate, which may also consist of a metal, in particular steel, stainless steel, stainless steel, titanium, a titanium alloy, magnesium, a magnesium alloy, an aluminum alloy, aluminum, or AlSiC.

[0032] Particularly preferably, the substrate material is of the same material class as the material of the metal pin, in particular the metal pin arranged in the fixing material, i.e. stainless steel metal pin with stainless steel substrate, or titanium metal pin with titanium or titanium alloy substrate, or vice versa, etc. The inventors have recognized that the selection of the same material class can suppress possible electrochemical corrosion, which can be advantageous for the production process, in particular during cleaning and / or electroplating, and can also contribute to a long service life of the final product, e.g., the igniter.

[0033] It is particularly preferred if the special steel of the at least one metal pin (5) is an alloy special steel according to the standard EN10020, particularly preferably a chromium-containing special steel.

[0034] Preferably, the special steel is -Ferritic special steel, -Precipitation hardening special steel, are selected from a group of

[0035] In some cases, martensitic special steel may also be considered.

[0036] It is surprising that a continuously stable feedthrough can be achieved with a glass-sealed metal pin made of special steel, since special steel does not have the aforementioned ratio of thermal expansion coefficients. That is, the thermal expansion coefficient of special steel is usually greater than that of the fastening materials used for the glass seal, in particular glass and / or glass-ceramic materials. The fact that even greater extraction forces can be achieved than with nickel-iron pins that actually fall within this ratio is a credit to the inventors and was not previously foreseen.

[0037] In this case too, there is a particularly suitable range. 金属ピン Or CTE(P) is 9.0 × 10 -6 / K~15.0×10 -6 / K, preferably 11.0 × 10-6 / K~14.0×10 -6 / K, preferably 11.5 x 10 -6 / K~14.0×10 -6 / K, or 11.0 x 10 -6 / K~13.5×10 -6 / K, particularly preferably 11.5 x 10 -6 / K~12.5×10 -6 It is preferred if the .lambda. is selected to be in the range of .lambda. / K.

[0038] In a preferred embodiment, the glass or glass-ceramic fixing material has a melting point of 4×10° C. at a temperature up to the Tg of the fixing material, in particular of the glass and / or glass-ceramic material. -6 1 / K~10.6×10 -6 Thermal expansion coefficient α in the range of 1 / K ガラス Advantageously, this state of thermal expansion is combined in particular with the above-mentioned state of thermal expansion of special steel.

[0039] The base has a thermal expansion coefficient α of the fixing material. ガラス At least 2×10 -6 1 / K, preferably 10×10 -6 1 / K high thermal expansion coefficient α 基体 It is more preferred if the compound has 基体 is 11 x 10 -6 1 / K~18×10 -6 1 / K. It is precisely in combination with one or, in particular, both of the above-mentioned conditions for the thermal expansion coefficients of the special steel and the fastening material that particularly advantageously a stable feedthrough, in particular a compressive glass-to-metal seal, is achieved.

[0040] The special steel for the metal pin can preferably be selected from the group of ferritic special steels, martensitic special steels or precipitation hardening special steels. Ferritic special steels are particularly preferred as they are particularly efficiently produced and / or fed to the manufacturing equipment.

[0041] In a preferred embodiment, at least one metal pin has at least one bending point, which is preferably bent in such a way that there is an axial offset S between the area of ​​the metal pin in the through hole and the connection area at the end of the metal pin opposite this area, which allows particularly good realization of a centrally located through hole in the basic body.

[0042] Furthermore, bent metal pins, especially S-shaped bent metal pins, when the special steel according to the invention is used as the material for the metal pins can provide a kind of spring function when assembled into a connector, which reduces the possibility of the connector system being damaged when plugged into the connector, for example, by the metal sleeve being pushed out of the plastic holder. Furthermore, peaks in mechanical loads are withstood by the glass material of the feedthrough.

[0043] The production of bent metal pins is more difficult with the special steel according to the invention than with the NiFe steel used hitherto, since the bending is carried out after annealing, and annealed special steel can only be plastically deformed by applying a greater force, as is evident from the hardness as mentioned above.

[0044] Preferably, the metallic fastening material feed-through has at least one further metallic pin electrically conductively connected to the substrate, in particular by soldering or welding, so that a direct electrical contact between the substrate and the second metallic pin is made, thereby making it possible to dispense with a second through-hole in the substrate.

[0045] In a preferred embodiment, the metal pin electrically connected to the substrate is made of non-specialty steel, particularly NiFe, at least in its core region, and is connected to the substrate by welding. Preferably, the metal pin is in an unannealed state, at least except for the region of the welded connection that is heated during welding. This material selection has the advantage that, as mentioned above, non-specialty steel in its unprocessed state is more mechanically load-bearing than annealed special steel. Therefore, this embodiment has the best mechanical strength values. However, producing a welded connection is more complex than brazing a second metal pin to the substrate.

[0046] In a preferred embodiment, the further metal pin also has at least one bending point, and is preferably bent in such a way that there is an axial offset between the region of the metal pin connected to the base and the connection region at the end of the metal pin opposite said region.

[0047] To optimize the soldering of the special steel metal pins with the brazing metal material, at least one metal pin sealed in the through hole and / or the metal pin electrically conductively connected to the base preferably has a nickel coating. The nickel coating is preferably provided at least in the area of ​​the glass seal and / or in the area of ​​the head surface of the glass-sealed metal pin and / or in the area electrically conductively connected to the base. Additionally or alternatively to the nickel coating, a gold layer may also be provided.

[0048] Particularly preferably, the gold layer is provided on the nickel layer at least in certain areas.

[0049] Therefore, in particular, nickel coatings in the area of ​​the glass-sealed metal pin where a gold layer is provided at least on the area of ​​the nickel layer, in particular in the connection area of ​​the end of this metal pin, and / or - in the area of ​​the glass-sealed metal pin in contact with the fastening material, and / or in the area of ​​the metal pins electrically connected to the substrate, where a gold layer is provided at least on the area of ​​the nickel layer, in particular in the connection area of ​​the end of the metal pin, and / or - a metal pin electrically conductively connected to a substrate, in the region where the metal pin is connected to the substrate by a metallic braze material, It is possible.

[0050] To ensure a reliable electrical connection, at least one metal pin glass-sealed in the through hole and / or the metal pin electrically conductively connected to the substrate is preferably gold-coated at least in a predetermined area. Preferably, a gold layer is provided at least in the connection area and / or in the connection area of ​​the metal pin electrically conductively connected to the substrate. The connection area is in particular the area where the metal pin is inserted into, for example, a connector system and / or where it comes into contact with a contact of the connector system.

[0051] In order to provide a metal fastening material feedthrough with a metal pin that can be processed or assembled as easily as possible, in this type of metal fastening material feedthrough, the metal pin, in the annealed state, is designed to withstand a force F exceeding 2.2 N when loaded vertically at the end point L in a test system having a metal pin length L of 11.68 mm. max The metal pin is further designed to break at a maximum displacement W of more than 0.15 mm, especially between 0.15 mm and 0.4 mm, when loaded perpendicularly at the end point L in a test system with a metal pin length L of 11.68 mm in the annealed state. max It can be designed to be elastically deformable up to W max is the limit of elastic deformation. W max If a load exceeding this is applied, plastic deformation, i.e. permanent bending of the metal pin, occurs.

[0052] If the actual metal pin has dimensions different from those of the test system, the metal pin is manufactured to the dimensions of the test system for comparison and / or the measurement results are converted to correspond to the dimensions of the test system.

[0053] The metal pins of the present invention made of stainless steel have significantly higher hardness after glass sealing and heating to 600°C or 650°C than NiFe pins. This is because NiFe softens at high temperatures, while stainless steel does not. Therefore, stainless steel allows for a pin load that is 50% higher after welding than NiFe, for example.

[0054] Metal fastener feedthroughs with metal pins made of special steel are distinguished by the extremely high mechanical stability of the metal pins, which prevents bending of the metal pins during assembly and post-processing, especially permanent or plastic bending. The use of special steel as the pin material ensures significantly higher mechanical stability than pins made of, for example, NiFe material.

[0055] Furthermore, the metal pins of the present invention in metal fastener feed-throughs for igniters of airbags or seatbelt pretensioners are unexpectedly distinguished by a very high extraction force of more than 250 N, in particular between 250 N and 400 N, preferably between 300 N and 380 N. This was surprising to those skilled in the art, because the thermal expansion coefficient of pins made of special steel is 11.0 x 10 at 650 °C. -6 / K~13.5×10 -6 / K range, and therefore in a different range from the glass material and the surrounding metal of the metal fastening material feedthrough, a relatively low extraction force was expected, which would have made the use of a metal pin made of special steel a disadvantage. Such a relatively high extraction force is believed to be due to improved chemical adhesion of the pin in the glass material, based on the pin material selected.

[0056] In a further embodiment, the special steel of the at least one metal pin is selected from a group of special steels whose transition point from elastic to plastic deformation in the annealed state is less than 50% of the transition point from elastic to plastic deformation in the unprocessed state.

[0057] This selection ensures that the metal pin does not soften so much that it can be plastically deformed under the mechanical loads that often occur after installation in the fastening material, in particular the glass material, and then after the metal fastening material feedthrough is installed in the opening in the substrate by heating the substrate to at least 600° C. or 650° C. The transition point from elastic to plastic deformation of the annealed metal pin is significantly reduced, which significantly reduces the strength and therefore the mechanical stability of the metal pin.

[0058] While the transition point from elastic to plastic deformation in ferritic special steel in the unprocessed state is located at a stress of 600 MPa and decreases to 500 MPa on the stress-strain graph upon heating to 600°C, for NiFe the transition point of 700 MPa decreases to 300 MPa on the stress-strain graph upon heating to 600°C. This means that NiFe steel is much more mechanically stable in the unannealed state than the special steel according to the invention. However, in the annealed state, the special steel is mechanically more load-bearing and can be elastically deformed, especially up to relatively high loads.

[0059] Since special steel does not soften as much as NiFe in the annealed state, the mechanical further processing of special steel is more difficult than NiFe. This is manifested, for example, in difficult bending properties when forming an S-shaped bend in a metal pin, as well as in more difficult processing for shaping the end of the metal pin, for example, grinding or embossing a portion with a curvature radius. In particular, the incompatible thermal expansion coefficients and the difficult post-processing have discouraged those skilled in the art from using special steel instead of NiFe as a material for metal pins.

[0060] The advantage of stainless steel as a pin material over conventional materials, such as NiFe, is that when combined with a stainless steel substrate, galvanic corrosion practically does not occur when a bridge wire is connected or when the substrate is covered with a conductive film. This is due to the slight difference in electrochemical potential between the stainless steel substrate and the stainless steel metal pin. The absolute value of the difference in electrochemical potential between the metal pin, especially a glass-sealed metal pin, and the substrate is aimed for to be at most 0.3 V. That is, the absolute value of the difference in electrochemical potential between the metal pin, especially a glass-sealed metal pin, and the substrate is preferably in the range of 0 to 0.3 V. This practically prevents galvanic corrosion. In contrast, when NiFe pins are used, electrons transfer from the NiFe pin to the substrate material, such as austenitic stainless steel, resulting in galvanic corrosion. For example, when ferritic stainless steel is used as the material for the metal pin, the electrical potential between the metal pin and the austenitic stainless steel substrate is substantially the same, and galvanic corrosion does not occur, unlike with NiFe pins.

[0061] The present invention further describes that the selection of materials for the substrate and / or metal pins can be based on their electrochemical potential with respect to seawater. This potential with respect to seawater is a suitable criterion for determining resistance to electrochemical corrosion, since under operating conditions, especially over long storage or operating periods, a film formed on the surface of the feedthrough may have similar corrosive properties to seawater.

[0062] According to this concept according to the invention, the material for the selection of the base body and / or at least one metal pin, in particular the metal pin located in the fastening material, is in particular special steel, whose absolute value of the electrochemical potential with respect to seawater is at most 0.36 V, i.e. correspondingly in the range from 0 to 0.36 V.

[0063] Since the special steel used as the pin material has only a very small difference in electrochemical potential compared to the special steel used as the base material, it is possible to provide a metal fastener feed-through for an igniter in an airbag and / or seat belt pretensioner, which has at least one metal pin fused into a through-hole in the base in a glass or glass ceramic fastener, where the at least one metal pin and the base consist of a compatible material combination so that no anodic and / or cathodic reactions occur on the surface of the base when an ignition bridge is attached, and where the surface of the feed-through is defined as the side on which the ignition bridge is to be attached and the underside is defined as the side of the metal fastener feed-through where the metal pin protrudes.

[0064] It is particularly preferred if the at least one metal pin and the substrate have substantially the same electrochemical potential, so that electrons do not flow through the ignition bridge via the absorbent water film on the water surface when the ignition bridge is installed. Preferably, the absolute value of the difference in electrochemical potential between the substrate and the stainless steel pin is merely 0.3 V to 0.0 V, i.e. the substrate has, for example, a potential of 0.07 V and the metal pin has a potential of 0.02 V, resulting in a difference of 0.05 V, so that there is virtually no flow of electrons from the metal pin to the substrate, via the ignition bridge and / or via the conductive film.

[0065] It is particularly preferable that the Cr content of the special steel is in the range of 10 to 30 weight percent, and more preferably in the range of 15 to 25 weight percent. Therefore, for example, when the chromium content is 20 weight percent, the Cr content is about 10 × 10 at 0 to 40°C. -6 An extremely low coefficient of linear expansion of 1 / K is achieved. The low coefficient of thermal expansion at 40°C also correlates with a low coefficient of thermal expansion at the glass sealing temperature, which is typically 600°C or 650°C.

[0066] To enable soldering of the special steel metal pin, the metal pin is provided with a nickel and / or gold layer, at least in certain areas, as described above. In this case, a nickel layer can be provided underneath the gold layer. Gold plating can also be applied directly to the special steel without a nickel interlayer.

[0067] Surprisingly, it was confirmed that when special steel is used as the material for the metal pin, the extraction force of the metal pin from the glass material is in the range of 250 N to 400 N, preferably 300 N to 380 N. Unexpectedly, this extraction force is about 50% greater than that of, for example, a NiFe metal pin.

[0068] A test system in which the metal pin is in the annealed state and has a metal pin length L of 11.68 mm, when loaded vertically at the end point L, will produce a force F of more than 2.2 N. max and / or the metal pin, in a post-heated state, when loaded vertically at the end point L in a test system with a metal pin length L of 11.68 mm, the maximum displacement W exceeds 0.15 mm, in particular 0.15 mm to 0.4 mm. max If the metal fastening material feed-through is designed to break at a certain point, the metal fastening material feed-through has a particularly stable metal pin. Such a stable metal pin is formed particularly if special steel, in particular chromium-containing special steel, is used as the material for the metal pin.

[0069] 11.0–13.5 × 10 at 650°C -6 The thermal expansion coefficient of this steel is 10.6 to 6.1 × 10 / K. -6Because the thermal expansion coefficient of the conductor is significantly higher than that of glass, which is in the range of 1 / K, those skilled in the art have been discouraged from using special steel in compression-type glass feedthroughs, for example, for use in airbag igniters. The inventors surprisingly discovered that, contrary to the prior art, which stipulates that the thermal expansion of the conductor must not be higher than that of the glass used in glass-to-metal feedthroughs to provide a sufficient seal, a tight glass seal can be provided even when the expansion coefficient of the metal pin is greater than that of the glass, provided that a positive bonding pressure is applied from the substrate to the glass, despite the large thermal expansion coefficient of the conductor, which is higher than that of the glass. A bonding pressure of more than 30 MPa, preferably more than 50 MPa, and particularly more than 100 MPa is particularly preferred. At such bonding pressures, a reliable glass seal is obtained. The bonding pressure is the pressure at the transition from the substrate to the glass material. In compression-type glass-to-metal seals, this pressure usually acts perpendicularly from the inner wall of the through-hole to the glass body. This pressure is an important factor in determining the removal force of the glass body from the substrate.

[0070] If a sufficient preload is applied to the glass from the substrate as the outer conductor, a high bonding pressure is provided. The bonding pressure between the glass and the inner conductor occurs after fusion and during cooling of the feedthrough. If this bonding pressure is very positive, i.e., greater than 30 MPa, or even greater than 50 MPa, and especially greater than 100 MPa, the transition between the glass and the metal is maintained, i.e., the transition from the glass to the metal pin is closed and thus hermetically sealed, despite the expansion coefficient of the metal pin being greater than that of the glass.

[0071] The bonding pressure depends directly on the strain difference between the glass and the surrounding metal. It also depends on the geometry. It is particularly advantageous if the area of ​​the substrate outside the through-hole is larger than the area of ​​the through-hole itself. The bonding pressure is a surface pressure. It is expressed as the force per unit area that presses the first object against the second object.

[0072] To achieve the required bonding pressure, the difference between the expansion coefficient of the substrate and the thermal expansion coefficient of the glass is at least 2 ppm / K, preferably at least 4 ppm / K, in which case the expansion coefficient α 基体 is the expansion coefficient of glass α ガラス In a particularly preferred embodiment, the coefficient of expansion of the metal pin is higher than the coefficient of expansion of the glass, α ガラス The expansion coefficient of the metal pin, α, is 1.1 times larger than 金属ピン In a particularly preferred embodiment, the expansion factor is selected to be 1.1α ガラス ~2.2α ガラス is in the range.

[0073] To apply the necessary pressure from the substrate to the glass material and to ensure a tight seal, the substrate is made of nickel-free, chemically resistant stainless steel (special steel).

[0074] The substrate, which may be the outer conductor, is preferably an austenitic special steel, which is distinguished by good weldability.

[0075] In addition to straight metal pins, the metal pins of the metal fastener feedthroughs may not be formed straight but may be bent.

[0076] The fixing material of the metal fixing material feedthrough is a glass material or a glass ceramic material. The expansion coefficient α of the glass material used is ガラス is 4 x 10 -6 / K~10.6×10 -6 / K, preferably 6.1 x 10 -6 / K~10.6×10 -6 / K range.

[0077] The substrate of the metal fastening material feedthrough, in which the metal pin is glass sealed, may have openings in various forms, as described, for example, in EP 1 813 906, EP 1 455 160 or EP 2 431 703. Cold forming, as described in EP 2 431 703, is one possibility, in which the openings are punched into the substrate.

[0078] In compression-type glass feedthroughs, such as those used in igniters for airbags and seatbelt pretensioners, the substrate material has an expansion coefficient α 基体 is selected to be greater than the expansion coefficient of the glass material, so that pressure is applied to the glass material, resulting in a compression-type glass-to-metal seal. In compression-type glass-to-metal seals, the expansion coefficient α is 18.3×10 -6 A substrate made of austenitic special steel of grade 1 / K is preferred.

[0079] A further aspect of the present invention is to provide a metallic fastening feedthrough, in particular for an igniter of an airbag and / or seat belt pretensioner, in which galvanic corrosion occurs only to a small extent. This is achieved in that at least one metal pin of the feedthrough and the substrate are made of a compatible material combination and are configured in such a way that anodic and / or cathodic reactions do not occur or occur only to a small extent on the surface of the substrate when an ignition bridge is attached or when the surface is coated with a conductive film.

[0080] At least one metal pin and the substrate have an electrochemical potential, and it is particularly preferred if the absolute value of the difference in electrochemical potential between the metal pin and the substrate is at most 0.3 V. Preferably, the electrochemical potentials of the metal pin and the substrate are substantially the same. In particular, the absolute value of the difference in electrochemical potential between the metal pin and the substrate is in the range of 0.1 V to 0.0 V, preferably 0.05 V to 0.0 V. The absolute value of the difference in electrochemical potential between the metal pin and / or the substrate with respect to seawater is preferably at most 0.36 V, in particular 0.36 V to 0.0 V.

[0081] At least one metal pin (5) consists, in particular at least in its core region, as well as the base, at least on its upper surface, of special steel according to standard EN10020.

[0082] In a further embodiment, the special steel of the metal pin and the base is selected such that the metal pin and the special steel of the base form a passivation film on their surfaces, preferably opposite an absorbent water film.

[0083] At least one metal pin is made of special steel according to the standard EN 10020 at least in its core area, and its thermal expansion coefficient α at a temperature of 650°C is 金属ピン is 9 to 15, preferably 11.0 x 10 -6 / K~14.0×10 -6 / K, preferably 11.5 x 10 -6 / K~14.0×10 -6 1 / K, or 11 x 10 -6 / K~13.5×10 -6 1 / K, particularly preferably 11.5×10 -6 / K~12.5×10 -6 It is in the range of 1 / K.

[0084] The glass or glass-ceramic fixing material is preferably 4×10 -6 1 / K~10.6×10 -6 Thermal expansion coefficient α in the range of 1 / K ガラス It has the following characteristics.

[0085] The substrate has a thermal expansion coefficient α ガラス At least 2×10 -6 1 / K, preferably 10×10 -6 1 / K higher, preferably 11 x 10 -6 1 / K~18×10 -6 Thermal expansion coefficient α in the range of 1 / K 基体 It is particularly preferred if the

[0086] The special steel of the at least one metal pin (5) is an alloy special steel, in particular according to the standard EN 10020, particularly preferably a chromium-containing special steel, particularly preferably selected from the group of ferritic special steels and / or precipitation-hardened special steels. The removal force of the metal pin from the glass material of the through hole (4) is preferably higher than 250 N, in particular between 250 N and 400 N, preferably between 300 N and 380 N.

[0087] In particular, the substrate consists of or essentially comprises a metal, in particular steel, stainless steel, special steel, titanium, titanium alloys, magnesium, magnesium alloys, aluminum alloys, aluminum, etc. Very particularly preferably, the substrate consists at least approximately of special steel of types 316, 317, 302, 304, 321, 317, 430, 410 and / or 416.

[0088] The metal pin has a maximum elastic deflection W of less than 0.13 mm, preferably less than 0.15 mm, particularly preferably less than 0.18 mm or less than 0.20 mm, very particularly preferably less than 0.24 mm, in particular in the range from 0.01 to 0.26 mm, converted into standard dimensions, in particular having a metal pin diameter of 1.00 ± 0.03 mm and a metal pin length of 11.68 ± 0.2 mm. max It has the following characteristics.

[0089] The metal pin, which is electrically conductively connected to the substrate, consists, in particular at least in its core region, of non-specialty steel, in particular NiFe, and is connected to the substrate by welding.

[0090] In a further configuration of the invention, at least one metal pin (5) glass-sealed in the through-hole and / or the metal pin (6) electrically connected to the substrate may be nickel-coated. Preferably, the nickel layer comprises: in the area of ​​the glass-sealed metal pins, where a gold layer is provided at least on the area of ​​the nickel layer, in particular in the connection area of ​​the end of the metal pin; the area of ​​the glass-sealed metal pin in contact with the fastening material; - in the area of ​​the metal pins electrically connected to the substrate, where a gold layer is provided at least on the area of ​​the nickel layer, in particular in the connection area of ​​the end of the metal pin, a metal pin conductively connected to the substrate, in the region where the metal pin is connected to the substrate by a metallic braze material; and combinations of these groups are present in the region of the metal pin.

[0091] Alternatively or additionally, at least one metal pin glass-sealed in the through-hole and / or the metal pin conductively connected to the substrate may be gold-coated, preferably with a gold layer at least on the connection region of the metal pin and / or the metal pin conductively connected to the substrate, located opposite the end of each metal pin located within the substrate and / or on the substrate surface.

[0092] The present invention will be explained in more detail below with reference to the drawings and examples, but the present invention is not limited to these examples. [Brief explanation of the drawings]

[0093] [Figure 1a] FIG. 1 shows a feedthrough according to the present invention mounted within an airbag igniter. [Figure 1b] 1 shows a metal fastening material feed-through, for example according to EP 2 270 417 A1, with a metal pin according to the invention; [Figure 2] FIG. 1 shows a test structure for detecting bending stiffness. [Figure 3a]FIG. 1 illustrates the expansion coefficients of the glass, substrate, and metal pin in a metal fastener feedthrough according to the prior art. [Figure 3b] FIG. 10 illustrates the expansion coefficients of the glass, substrate, and metal pin in a metal fastener feedthrough according to the present invention. [Figure 4] This figure shows the stress-strain curves of heated and unheated NiFe and special steel (AISI430). [Figure 5] FIG. 10 is a plan view showing the casing components with openings and metal pins glass sealed within the openings. [Figure 6] FIG. 10 is a diagram showing the removal force of a metal pin made of NiFe / special steel. [Figure 7] FIG. 1 is a diagram showing the dependence of the expansion coefficient of special steel on the Cr ratio. [Figure 8] FIG. 1 is a diagram showing chromium content. [Figure 9] FIG. 1 is a diagram showing the chromium equivalent and nickel equivalent in special steel. [Figure 10a] FIG. 1 shows the head of a metal fastener feedthrough with a bridgewire. [Figure 10b] FIG. 1 is a diagram illustrating a chemical reaction based on a difference in electrochemical potential according to the prior art. [Figure 10c] FIG. 1 is a diagram illustrating a chemical reaction based on a difference in electrochemical potential according to the present invention. [Figure 11] FIG. 1 shows the electrochemical potential as a function of material selection. DETAILED DESCRIPTION OF THE INVENTION

[0094] FIG. 1a shows an exemplary configuration of a metallic fastener feedthrough 1 in axial cross section, preferably for use in an igniter or ignition device of an airbag or other personal protection device, such as a seatbelt pretensioner, as described, for example, in EP 2 270 417 A1. The metallic fastener feedthrough includes two metallic pins 5, 6 formed as metallic pins according to the present invention and including, but not limited to, special steel as the metallic pin material. The metallic fastener feedthrough has a base body 1 to which, in this embodiment, one of two parallel metallic pins 5, 6 is electrically connected. In the illustrated embodiment, the two metallic pins 5, 6 are arranged parallel to each other. In this case, one functions as a conductor, and the other is arranged as a ground. In the illustrated example, the first metallic pin 5 functions as a conductor, and the second metallic pin 6 functions as a ground pin. The ground pin 6 is electrically connected to the base body 1, for example, by a solder joint 7 using a soldering material. The width of both metal pins is usually in the range of 0.98 to 1.05 mm, and is preferably 1.0 mm.

[0095] At least one of the metal pins, in particular the metal pin 5, which functions as a conductor, is guided through the base body 1. For this purpose, the metal pin 5 is fused over a portion of its length into the fastening material 10, in particular into the glass stopper that has cooled from the glass melt. The metal pin 5 protrudes on at least one side beyond the end face of the glass stopper 10, usually on the underside of the base body, and in the illustrated embodiment, after fabrication, is flush with a second end face of the glass stopper 10 that is flush with the upper face 11 of the base body 1. For this purpose, the metal pin 5 can be arranged in the through-hole 4 so that during fusion, the metal pin first protrudes beyond the base body 1. After fusion or embedding, the metal pin 5 and, if necessary, the protruding and cooled fastening material 10 can be polished so that the metal pin and / or the fastening material are flush with the end face of the glass stopper 10 and the upper face 11 of the base body 1. Further variations are also possible. The fusing of the metal pin into the glass material and the fusing of the glass material into the substrate are usually carried out at temperatures above 600°C or 650°C, depending on the glass material used. 基体 ~18.3×10 -6 / K is 4 x 10 -6 / K~10.6×10 -6 / K range of thermal expansion coefficient α ガラス材料 Since the temperature of the base metal is higher than that of the glass material, after cooling, the base body applies a certain pressure to the fastening material, particularly the glass material, and a compression-type glass seal is formed. However, heating also affects the mechanical stability of the metal pins. That is, metal pins generally soften under temperature stress. The inventors have recognized that when used for feedthroughs, special steel does not soften as significantly as NiFe under temperature stress. The special steel maintains significantly more bending rigidity than the NiFe pins currently used in feedthroughs.

[0096] In the illustrated case, the earth pin 6 is attached directly to the rear surface of the substrate 1, for example by means of a brazing material 7. This is usually a metallic brazing material. Like the glass-sealed metal pin 5, the earth pin 6 may also be made of special steel, preferably Cr-containing special steel, according to the invention.

[0097] In one embodiment, the base body 1 may be formed as a stamped part. It is a stamped part if at least the through holes 4, and preferably also the final geometry of the base body 1, are formed by stamping. According to one embodiment, the geometry of the outer contour, and in particular the outer contour of the base body 1, can be produced by shearing, preferably by stamping. The stamped part can be further used while maintaining its geometry after the stamping process, but can also be deformed in further work steps, preferably immediately thereafter, such as embossing or deep drawing. Alternatively, the entire base body can be formed by cold deformation, as described in EP 2 431 703 A1.

[0098] The through-hole 4, which is provided for receiving and fixing the metal pin 5 by the glass stopper 10, is formed in the form of a hole by a punching process. Then, the metal pin 5 is introduced into the through-hole 4 together with the glass stopper 10 at the back surface 11 of the base 1 of the metal fixing material feed-through, and the metal body including the glass stopper 10 and the metal pin 5 is heated to about 600°C, so that after the cooling process, the metal contracts and a friction-fit bond is formed between the glass stopper 10 including the metal pin 5 and the base 1, which is also called a compression-type glass-to-metal seal. Such a compression-type glass-to-metal seal can be achieved due to the different thermal expansion coefficients of the base 1 and the glass material of the glass stopper 10.

[0099] Alternatively, it is also conceivable to introduce the fastening material 10, in particular a glass melt, into the through-hole 4 from the front side in a molten or fluid state. In this case, a positive and material-tight bond between the outer periphery of the metal pin 5 and the inner periphery of the through-hole 4 is formed during cooling. The base body 1 may be configured so that the ratio between the thickness of the base body 1 and the maximum extension of the through-hole 4 perpendicular to its axis is in the range of 0.5 to 2.5.

[0100] It should be emphasized that the invention can also be deployed with insulating materials in the through holes 4 that are not based on glass materials.

[0101] 1a shows the installation of a metal fastener feedthrough in an igniter component, e.g., an airbag igniter. The igniter component includes an igniter cap 2 containing a pyrotechnic charge 25 for the igniter component, i.e., an airbag igniter, in addition to the metal fastener feedthrough in which a metal pin 5 is glass-sealed. The pyrotechnic charge 25 is triggered by an electrical impulse in a bridge wire 9. The bridge wire 9 connects the glass-sealed metal pin 5 to a substrate 1 that is placed on earth. Typically, the bridge wire 9 rests on the surface of the substrate 1 and / or fastener 10, unlike in the drawings, which show the bridge wire 9 only diagrammatically.

[0102] 1a also clearly shows a bending point 50 of the glass-sealed metal pin, which causes an offset S of the axis of the region of the metal pin 5 that is glass-sealed in the through-hole and the connection region of the metal pin. This offset is selected so that the metal pin of the metal fastening material feed-through can be introduced, for example, into a connector system. Typically, both metal pins 5, 6 are positioned and / or bent in such a way that, in an overall view, there is a central positioning of one of both metal pins 5, 6 relative to the base 1.

[0103] FIG. 1b shows a cross-sectional view of a metal fastener feedthrough mounted in an igniter cap 2, including a base 1 with metal pins 5 and 6. Components identical to those in FIG. 1a are designated by the same reference numerals. Unlike the embodiment shown in FIG. 1a, in the configuration of FIG. 1b, the metal pin 6 also has a bend point 60, resulting in an axial offset between the area of ​​the metal pin connected to the base 1 and the area of ​​the metal pin's connection at the opposite end. A bridge wire 9 between the base 1 and the metal pin 5 is clearly visible in FIG. 1b. Unlike the stamped base of FIG. 1a, the base of FIG. 1b is cold-formed as in EP-A-2 431 703 and has an open area 17. After providing the open area 17 as in EP-A-2 431 703, an opening 10 is punched out of the cold-formed base.

[0104] A measuring device or test system for determining the bending strength of a metal pin is shown in Figure 2. Figure 2 shows a clamped metal pin 300 having a length L = 11.68 mm and a diameter of 1.0 mm, on which a force F, indicated at 110 and measured in units of Newtons (N), acts.

[0105] In the test system or measurement device shown in Figure 2, the wall to which the pin is clamped is designated 400, the pin of length L is designated 300, and the end point of the metal pin in an unloaded state is designated 301. The bent or loaded pin is designated 310, and the end point of the bent pin is designated 302. The difference between end points 301 and 302 is the maximum displacement W. max This shows:

[0106] In the raw state, a NiFe metal pin deflects 0.345 mm when subjected to a force of 6.380 N. At larger forces and deflections, the elastic deformation transitions to irreversible plastic deformation. At forces greater than 6.380 N and / or bending plastic deformation greater than 0.345 mm, the pin may break.

[0107] If a NiFe pin is heated to, for example, the glass sealing temperature of 650°C, after cooling (annealing), a force of only 1.933 N applied to the metal pin results in a deflection of 0.105 mm. In the annealed state, forces greater than 1.933 N and deflections greater than 0.105 mm transition the elastic deformation to plastic deformation, as described above for the unprocessed state. This consideration of force loading indicates that the NiFe pin loses significant mechanical stability upon heating.

[0108] In contrast, when special steels, such as ferritic special steels, especially AISI 430, are used, the unprocessed state requires a force of 4.976 N and a deflection W of more than 0.269 mm. max In the annealed state, a force of 3.984 N and / or a deflection of 0.216 mm, W max This shows that after a heat treatment at, for example, 650 °C, the mechanical stability and / or maximum achievable deflection potential of ferritic special steel (AISI 430) in the test system is approximately 100% higher than that of the NiFe 47 pin.

[0109] The above W max In these examples, the value of W represents the boundary value at which elastic bending of the metal pin still exists. If the mechanical load in this example exceeds this boundary value, the bending will of course continue. max above this value, which is a plastic deformation, i.e., irreversible.

[0110] In practice, this means that the stainless steel pin is significantly more rigid in bending than the NiFe47 pin, which is softened significantly by the glass sealing process at a temperature of, for example, 650° C. Therefore, with the stainless steel, after heating, i.e. in the annealed state, in a test system with a metal pin length L of 11.68 mm, the normal load at the end point is greater than 2.5 N, preferably greater than 3 N, particularly preferably greater than 3.2 N or 3.5 N, in this example a force F of 3.984 N. maxThis provides a material that allows the metal pin to be designed so that plastic deformation only occurs at this temperature.

[0111] This corresponds to the maximum elastic bending potential and / or displacement W in the test system described above. max is preferably greater than 0.15 mm, and in particular is in the range of 0.15 mm to 0.3 mm and / or 0.4 mm.

[0112] The risk of the metal pin being damaged under mechanical loads in further processing, especially when bending forces are applied during assembly, is thereby significantly reduced by the invention.

[0113] 3a and 3b show the difference in coefficient of expansion between a conventional feedthrough and a feedthrough according to the invention.

[0114] Figure 3a shows the coefficient of expansion for a conventional metal fastener feedthrough, where CTE(H) is the coefficient of expansion of the substrate or header, α 基体 CTE(G) is the expansion coefficient of the fixed material α ガラス CTE(P) is the coefficient of expansion of the metal pin placed in the fixing material, α 金属ピン As is clear from FIG. 3a, in order to provide a compressive glass-to-metal seal, the expansion coefficient (CTE(H)) of the substrate is significantly larger than the expansion coefficient (CTE(G)) of the fixing material, particularly the glass. For example, when austenitic special steel is used as the substrate material, the expansion coefficient (CTE(H)) of the substrate is 18.3×10 -6 / K range. ガラス The coefficient of expansion (CTE(G)) of glass materials, also called -6 / K~10.6×10 -6 / K, which is significantly lower than the expansion coefficient CTE(H) of the substrate. In the prior art, the expansion coefficient CTE(P) of the metal pin was always lower, even if only slightly, than the expansion coefficient of the surrounding glass material. Until now, it was assumed that this was necessary to achieve a durable fastening material feedthrough, since otherwise the metal pin would be liable to come off the glass during thermal fluctuations. Therefore, until now, metal pins made of non-specialty steels, especially NiFe, have been used for such applications.

[0115] Figure 3b shows the expansion coefficient of a feedthrough according to the invention with a metal pin made of special steel. As can be seen from Figure 3b, the expansion coefficient of the metal pin (CTE(P)) is lower than the expansion coefficient of the substrate (CTE(H)), but higher than the expansion coefficient of the fastening material (CTE(G)). The special steel has a coefficient of expansion of 11.0-13.5 x 10 -6 / K, whereas the coefficient of expansion of the mounting material, e.g., glass, is typically only 4×10 -6 / K~10.6×10 -6 / K range, especially 6.1 × 10 -6 / K~10.6×10 -6 / K, i.e., lower than the expansion coefficient of the metal pin. Therefore, unlike the prior art as shown in FIG. 3a, the expansion coefficient of the metal pin is higher than the expansion coefficient of the glass material, but the expansion coefficient α 基体 Or if a positive bonding pressure is applied from a substrate having a CTE(H) to glass, α 金属ピン >α ガラス A sufficient sealing performance and compression-type glass-to-metal seal can be achieved even with a metal pin made of special steel. When a high joining pressure is applied from the substrate to the glass material and metal pin, the transition between the glass and the metal, especially the transition from the glass to the metal pin, remains closed, ensuring a tight seal. In particular, a hermetic seal can be achieved. A sufficiently high joining pressure can be preferably reached if, in plan view, the area of ​​the substrate minus the area of ​​the through-hole corresponds to at least 1.2 times the area of ​​the through-hole.

[0116] Figure 4 shows the stress-strain curves for the stainless steel pin according to the present invention and, by comparison, the stress-strain curve for a NiFe pin (NiFe47). As can be clearly seen from Figure 4, the NiFe pin significantly loses stability and becomes brittle after heating, for example, to 650°C, as required for glass sealing, especially compared to the stainless steel pin (AISI430) made of ferritic stainless steel. Thus, for the ferritic stainless steel AISI430, the transition point from elastic to plastic deformation, at a strain of approximately 0.25%, shifts from a stress of approximately 600 MPa for the unprocessed material to a stress of 500 MPa for the annealed material. That is, the stress at the transition point decreases by only approximately 20%. In contrast, for NiFe metal pins, the transition point from elastic to plastic deformation, located at approximately 0.25% strain upon heating, shifts from a stress of 700 MPa to a stress of 200 MPa, i.e., the transition point for the raw material is 3.5 times higher than that for the annealed material. This indicates that stainless steel materials are more advantageous than NiFe as pin materials for systems in which the metal pins exist in a heat-treated, particularly annealed, state. This is all the more remarkable given that the strength of NiFe metal pins in the raw, i.e., unheat-treated, state is significantly higher than stainless steel pins, and thus the previously non-specialty steel pins appear to be suitable for this reason in addition to the appropriate thermal expansion discussed above.

[0117] 5 shows a casing component in plan view, which includes an opening 1000 into which a pin 1020 is inserted and which is glass-sealed in a glass material 1010. Furthermore, FIG. 5 shows the joining pressure P1 from the glass material to the metal pin and the joining pressure P2 from the base or casing component to the glass material. According to the invention, if the expansion coefficient of the metal pin is higher than that of the glass material, a sufficient compressive preload of the base or casing component onto the glass must be applied in order to achieve a sufficient seal. This is achieved, in particular, if the above-mentioned geometrical requirements are met.

[0118] Surprisingly, Figure 6 shows that the use of special steel pins allows for extraction forces up to 50% greater than the previously used metal pins made from nickel-containing iron material (NiFe47). As shown in Figure 6, the extraction force for NiFe47 is only 207.7N for the uncoated material, while the extraction force for the nickel-coated NiFe47 pin is 225.2N.

[0119] Surprisingly, significantly higher extraction forces can be achieved with metal pins made of stainless steel, especially ferritic stainless steel. This is particularly surprising because, as explained, the thermal expansion coefficient of stainless steel pins is rather unfavorable. For ferritic stainless steel AISI 446, an extraction force of 331.2 N is achieved without a nickel coating, and an extraction force of 358.1 N is achieved with a nickel coating. For stainless steel AISI 430, the extraction forces are somewhat lower: in this case, the extraction force is 317.5 N without a nickel coating and 327.3 N with a nickel coating. This shows that stainless steel metal pins are superior to conventional NiFe metal pins not only by their higher mechanical strength, but also by their higher extraction forces. Therefore, it can be inferred that the improved removal force of the metal pin made of special steel is based on the fact that the material of the metal pin remains harder than the material of the NiFe pin after heating, so the special steel can withstand with greater force the joining pressure that the header transmits to the metal pin through the glass, and is, so to speak, hardly pressed in.

[0120] A nickel or gold coating or a gold coating over a nickel coating on one or more of the metal pins not only provides a high extraction force but also helps to make the metal pins easier to contact.

[0121] Figure 7 shows the effect of chromium content in special steels, such as those used in metal pins, on their coefficient of thermal expansion α or CTE(P). The coefficient of linear expansion between 0 and 40°C is expressed in ppm / °C, i.e., ×10 -6 / K for chromium contents of 0 to 60 weight percent. As can be seen from Figure 7, for special steel AISI 443 containing a chromium content of about 20 weight percent, the -6 A thermal expansion coefficient of 1 / K is obtained. It can be seen that the CTE generally depends on the chromium content. According to FIG. 7, a local minimum in the CTE is reached at a chromium content of approximately 20% by weight. In other words, special steels that are particularly suitable for the metal pin are selected so that their chromium content lies in the region around the local minimum in the CTE, particularly in the range of 10% to 30% by weight, and particularly preferably in the range of 14% to 28% by weight. The special steels SUS430, AISI443, and SUH446 are within this range and can be used particularly advantageously as materials for the metal pin. The same can be said for AISI446 and AISI430.

[0122] As will be explained below, materials with such chromium contents or chromium equivalents also have advantages in terms of electrochemical potential.

[0123] Figure 9 shows the chromium equivalent and nickel equivalent of martensitic and austenitic special steels.

[0124] The chromium equivalents, which take into account the proportions of molybdenum, silicon, and niobium in addition to chromium, are given for martensitic and ferritic special steels. The chromium equivalents are in the range of 10 to 30 weight percent, in particular in the range of 12 to 28 weight percent. Ranges that are particularly preferred within the context of the present invention are marked with dashed lines in Figure 9.

[0125] Generally, the special steel according to the present invention can be said to comprise or be a chromium alloy steel or to have a certain chromium equivalent, where the chromium equivalent is %Cr + %Mo + 1.5 x %Si + 0.5 x %Nb. The chromium equivalent usually indicates the total ferrite forming elements of an austenitic special steel alloy according to the empirical formula of Schaeffler and DeLong. A particularly preferred range of chromium equivalent is the circled range in Figure 9.

[0126] Figure 10a shows the head portion of a metal fastening material feedthrough according to the present invention, and Figures 10b-10c show schematic diagrams of the electrochemical reactions in the area of ​​the metal fastening material feedthrough based on different electrochemical potentials in the prior art and the present invention.

[0127] FIG. 10a first shows the head portion of a glass-to-metal fastening feedthrough according to the present invention, as shown in FIGS. 1a and 1b. Components identical to those in FIGS. 1a and 1b are designated by the same reference numerals. FIG. 10a shows that a conductive film, e.g., a water film 200, can form on the surface of the substrate 1. This can lead to a flow of electrons from the metal pin to ground (in this case, the substrate 1) if the electrochemical potentials of the substrate and the metal pin are different, potentially resulting in oxidation of the metal pin and / or the substrate, and / or the fastening material, e.g., the glass material. The flow of electrons from the metal pin to the substrate occurs via a bridge wire 9. The conductive film 200 can occur, particularly with long-term use of the aforementioned type of feedthrough, and significantly influences the long-term use of the feedthrough and the corrosion attack on the feedthrough. Electrons flow from the head of the metal pin 500 to the substrate 501 via the bridge wire 9, or possibly in another direction depending on the potential difference. The insulating material between the substrate and the metal pin is typically a non-conductive fastening material, preferably a glass or glass-ceramic material. The glass or glass-ceramic material in which the metallic conductor is sealed is designated 10. The metal pin guided through the opening is designated 5, and the metal pin brazed to the substrate by means of brazing material 7 is designated 6.

[0128] 10b shows the flow of electrons from the metal pin to the substrate due to the difference in electrochemical potential. This corresponds to the prior art. Thus, the difference in electrochemical potential between the metal pin made of non-specialty steel, in particular NiFe, and the substrate exceeds 0.3 V in the prior art. Due to this difference in electrochemical potential, if a conductive layer is present on the metal pin and the substrate, for example, if a water film 200 is present, the iron will be converted to Fe 2+ When water is present, oxygen converts the electrons to 2OH, as shown in Figure 10b. - This means that the water film becomes more and more basic, and the material of the metal pin oxidizes to form Fe 2+10b. The same reference numerals as in Figure 10a are used in Figure 10b. Thus, 500 denotes the metal pin region, and 501 denotes the substrate region. Electrons flow from the metal pin to the substrate through the bridge wire 9, or even through the conductive film 200 if the conductive film becomes increasingly basic as the reaction progresses. The increasing basicity of the film 200 could enhance the corrosion effect on the metal, and even on glass materials. The layer 5110 on the stainless steel substrate is a passivation layer formed on the stainless steel, which can contain oxygen. When NiFe is used as the pin material, it can be observed that localized cells can form between this passivation layer 5110 and the non-stainless steel metal pin, specifically NiFe. The electrochemical potential difference between NiFe as the pin material and, for example, AISI 304L as the substrate material is 0.38 V. In this case, electrochemical corrosion could occur.

[0129] Thus, while in the prior art the metal pin would corrode, according to the present invention, the metal pin has approximately the same electrochemical potential in region 500 as the substrate, designated by reference numeral 501, so corrosion no longer occurs, or at least is significantly suppressed. Even if the substrate and metal pin are provided with a conductive film 200, particularly a water film, as shown in FIG. 10c, no electrons flow from the metal pin to the substrate. The surface 5110 of the substrate, and particularly the metal pin, is a passivation layer formed on stainless steel, which may contain oxygen but does not oxidize further. In particular, no increasingly basic water film forms.

[0130] When AISI 430 is used as the material of the glass-sealed metal pin and AISI 304 is used as the material of the substrate, the absolute value of the electrochemical potential difference is 0.02 V. In this case, the electrochemical corrosion effect is at least very significantly suppressed.

[0131] Components that are the same as those in the previous figures are given the same reference numerals. Preferably, in a component according to the invention, the absolute value of the difference in electrochemical potential between the substrate and the stainless steel pin is simply 0.3 V to 0.0 V, preferably 0.1 V to 0.0 V, particularly preferably 0.05 V to 0.0 V.

[0132] FIG. 11 shows the electrochemical potential profile of materials, particularly high-grade steel, that can be selected for the metal pin and / or for the base body. As explained above, a suitable material combination for the base body and the metal pin in the fastening material is important for good corrosion resistance. When selecting materials, efforts should be made to minimize the potential difference. However, the base body material must also fulfill other requirements. In particular, the base body must be weldable to the metal cap 2, particularly by laser welding. The method of manufacturing the base body is also an issue, particularly if the base body is stamped or cold-formed. If the base body is cold-formed, a certain copper content may be advantageous.

[0133] When selecting the metal pins 5, 6, in particular the metal pins 5 arranged in the fastening material, and also for the selection of the material of the substrate, the materials listed as stainless steel in Fig. 11 are particularly suitable. These are stainless steel types (AISI) 316, 317, 302, 304, 321, 317, 430, 410 and / or 416. All of these have a small electrochemical potential difference with respect to seawater, in particular an absolute value of less than 0.4 V, preferably less than 0.36 V, which, as explained, is a good measure for determining the resistance to galvanic corrosion for the entire feedthrough.

[0134] Thus, for the first time, the present invention provides a metal fastening material feedthrough which, on the one hand, is distinguished by relatively high mechanical stability, especially when bending the metal pin, and / or by relatively high extraction force of the metal pin, and preferably also by relatively low corrosion resistance, especially under adverse application conditions.

[0135] The improved mechanical stability can reduce assembly errors, which leads to improved reliability and / or fewer rejects. The improved corrosion resistance can provide long-term stability and thus reliability of devices in which the feedthrough according to the invention is installed. Overall, the efficiency of manufacturing objects including the feedthrough according to the invention as well as their safety can be increased.

Claims

1. A metallic fastener feedthrough for an igniter of an airbag and / or seatbelt pretensioner, comprising at least one metal pin (5) fused in a through-hole (4) of a base (1) in a glass or glass-ceramic fastener (10), A positive bonding pressure is applied from the substrate (1) to the fixing material (10), The at least one metal pin (5) is made of special steel according to the standard EN 10020, at least in its core region, the special steel being a ferritic special steel, and the at least one metal pin (5), converted into standard dimensions having a metal pin diameter of 1.00±0.03 mm and a metal pin length of 11.68±0.02 mm, has a maximum elastic deflection W of at least 0.15 mm. ｍａｘ and The special steel of the at least one metal pin (5) has a thermal expansion coefficient α 基体 But 9 x 10 －６ / K~15 x 10 －６ / K, said at least one metal pin (5) having at least one bending point (50); The bend of the metal pin (5) is S-shaped, the bending of the metal pin (5) is designed so that there is an axial offset (S) between the area of ​​the metal pin (5) in the through hole (4) and the connection area at the opposite end of the metal pin (5), Metal fastening material feedthrough.

2. The special steel is selected so that it will deflect by a maximum of 0.21 mm under a mechanical load in the range of 3N to 4N. The metallic fastener feedthrough of claim 1 .

3. a mechanical load of 0.25% (strain) of said at least one metal pin (5) corresponds to a stress of more than 450 MPa; 3. A metal fastener feedthrough according to claim 1 or 2.

4. The extraction force of the metal pin (5) from the fastening material (10) in the through hole (4) is greater than 250 N; 4. A metal fastener feed-through according to claim 1.

5. The substrate (1) consists of metal and / or essentially contains metal, 5. A metal fastener feed-through according to any one of claims 1 to 4.

6. the special steel of the at least one metal pin (5) is an alloy special steel according to the standard EN 10020; 6. A metal fastener feed-through according to any one of claims 1 to 5.

7. The glass or glass-ceramic fixing material (10) has a melting point of 4×10° C. at a temperature up to the Tg of the fixing material. －６ / K~10.6 x 10 －６ / K range of thermal expansion coefficient α ガラス It has 7. A metal fastener feed-through according to any one of claims 1 to 6.

8. The substrate (1) has a thermal expansion coefficient α of the glass that is at least 2×10 －６ / K, and has a high thermal expansion coefficient α.

8. A metal fastener feed-through according to any one of claims 1 to 7.

9. The metal fastening material feedthrough is designed as a compressed glass feedthrough; 9. The metal fastening material feed-through according to claim 8, wherein the substrate (1) exerts a joining pressure of more than 30 MPa on the glass or glass-ceramic fastening material (10).

10. 10. The metal fastening material feed-through according to claim 1, wherein the at least one metal pin (5) glass-sealed in the through-hole (4) is coated with nickel and / or gold.

11. At least one other metal pin (6) is electrically conductively connected to the base (1); 11. A metal fastener feed-through according to any one of claims 1 to 10.

12. The other metal pin (6) electrically connected to the base body (1) is made of non-specialty steel at least in its core region, and the other metal pin (6) is connected to the base body (1) by welding. The metallic fastener feedthrough of claim 11.

13. The other metal pin (6) has at least one bending point (60). The metallic fastener feedthrough of claim 11.

14. The other metal pin (6) electrically connected to the base (1) is nickel coated. The metallic fastener feedthrough of claim 11.

15. The other metal pin (6) electrically connected to the substrate (1) is gold coated. The metallic fastener feedthrough of claim 11.

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