Pyrotechnic penalty

Abstract

Pyrotechnic tensioner (10) for a safety system in a vehicle, comprising a gas generator (22) having a propellant charge (26) and an igniter (32), and a housing (12) in which a pressure chamber (14) is provided into which the gas can flow and in which a piston can be moved in the tensioning direction by the gas, and a tension transmission means connected to the piston which extends longitudinally out of the pressure chamber (14), wherein an end piece (16) is provided on the housing (12) which closes the pressure chamber (14) in the opposite direction to the tensioning direction and in which a chamber (24) is provided into which the propellant charge (26) is filled and whose wall forms the wall of the propellant defined by the propellant charge (26), characterized in that the end piece (16) is made of plastic and is at least partially enclosed by a metal tube (38),and that the pressure chamber (14) is closed by a plug receptacle (32) on the end face facing away from the traction transmission means.

Description

[0001] The invention relates to a pyrotechnic tensioner for a safety system in a vehicle, comprising a gas generator having a propellant charge and an igniter, and a housing in which a pressure chamber is provided into which the gas can flow and in which a piston can be moved through the gas.

[0002] A pyrotechnic tensioner, such as an end-fitting tensioner for a seat belt in a vehicle, has an elongated, cylindrical housing in which a piston is mounted to slide longitudinally. A tension transmission element is attached to this piston and connected to a component of a vehicle safety system, such as the end fitting of a seat belt. To move the piston longitudinally and thus, for example, tighten the seat belt, a pyrotechnic gas generator is provided. This generator creates overpressure in the chamber, which moves the piston. Typically, the housings and gas generators are manufactured separately and assembled immediately before installation in a vehicle. A coupling piece is provided on the housing for connecting the gas generator. However, this requires increased manufacturing effort.Furthermore, the installation of these tensioners is very complex.

[0003] Gas generators are also known from the prior art in which an end piece sealing the pressure chamber has a receptacle for the gas generator, into which the gas generator can simply be inserted. However, even with these tensioners, additional components are required to fix the gas generator in the end piece and thus to the housing.

[0004] Alternatively, there are also pressure boosters in which the propellant charge of the gas generator is already located inside the pressure chamber. However, the installation of these boosters is also very complex, as the propellant charge must be positioned within the pressure chamber and reliably protected from external influences.

[0005] From generic US 4,422,669 A, a pyrotechnic tensioner for a vehicle safety system is known, comprising a gas generator, a propellant charge, and a detonator. The housing of the tensioner includes a pressure chamber into which the gas can flow and in which a piston can be moved by the gas in the tensioning direction. A tension transmission element is connected to the piston and extends longitudinally out of the pressure chamber. The housing has an end piece that closes the pressure chamber against the tensioning direction and contains a chamber into which the propellant charge is filled, the wall of which forms the wall of the propellant charge defined by the propellant.

[0006] From EP 0 780 271 A2 and DE 10 2006 052 332 A1, a pyrotechnic blaster is known in which the propellant is designed as a so-called micro gas generator. Its construction consists of a closed housing containing the ignition element and propellant charge. This complete propellant assembly, comprising the propellant charge, igniter, and receiving housing, is inserted into an end piece.

[0007] Furthermore, a rotary-acting pyrotechnic tensioner is known from US patent 5,944,276 A.

[0008] The object of the invention is therefore to provide a pyrotechnic tensioner that has a simpler design and thus requires less manufacturing effort.

[0009] In a pyrotechnic trigger according to the invention, the propellant chamber does not need to be arranged so that it connects directly to the pressure chamber. A gas flow channel can also be provided in the end piece, which, in the event of triggering, fluidically connects the propellant chamber to the pressure chamber. The position of the propellant chamber, i.e., the shape of the end piece, can thus be adapted as desired to the installation conditions in a vehicle, offering greater design flexibility.

[0010] Preferably, a rupture wall is present in the end section between the propellant chamber and the pressure chamber. This rupture wall seals the propellant chamber from the pressure chamber, thus protecting the propellant from, for example, moisture or other influences. Only upon activation is this rupture wall breached by the overpressure generated in the propellant chamber by the ignited propellant, thereby establishing a fluid connection between the propellant chamber and the pressure chamber.

[0011] A tension transmission element of a vehicle safety system, such as a seat belt, is typically provided on the piston. This element must extend longitudinally out of the housing, i.e., the pressure chamber, to ensure proper transmission of the tension force to the safety system. For this reason, the end piece preferably has a guide channel for such a tension element, through which the tension element is guided out of the housing.

[0012] Since the pulling element extends longitudinally out of the pressure chamber and thus out of the housing, the propellant chamber cannot be arranged longitudinally as an extension of the pressure chamber. Therefore, the end piece preferably has a first section in which the guide channel, and in particular the gas guide channel, is located, and a laterally projecting second section, arranged at right angles to the first section, in which the propellant chamber is located. The end piece is thus T- or L-shaped, with the first section serving as a closure for the pressure chamber and the propellant charge being arranged in the second section, which can be fluidically connected to the pressure chamber via the guide channel.

[0013] To trigger the gas generator, an igniter is preferably provided at the end piece.

[0014] The igniter is located, for example, on the second section, making it easily accessible and allowing for simple contact between the pyrotechnic tensioner or the gas generator and the igniter.

[0015] In particular, the generator's propellant chamber can be sealed by the detonator. In this embodiment, the chamber is sealed on one side by the rupture wall. On the other side, the chamber is initially open, allowing the propellant to be poured in. After the propellant is poured in, the detonator seals the chamber, making it hermetically sealed and the propellant safely protected. This also simplifies assembly, as no separate elements are required to seal the propellant chamber.

[0016] According to the invention, the end piece is made of plastic, which means it can be easily manufactured using an injection molding process.

[0017] To ensure greater stability, the housing according to the invention has a metal tube that at least partially encloses the end piece.

[0018] Furthermore, according to the invention, the pressure chamber is closed by a plug receptacle on the end face facing away from the traction transmission means.

[0019] The detonator, for example, is a prefabricated, self-contained component separated from the propellant charge by a detonator housing.

[0020] Further advantages and features can be found in the following description in conjunction with the attached drawings. These show: - Fig. 1 a sectional view through a pyrotechnic tensioner according to the invention, - Fig. 2 a second sectional view through the tightener from Fig. 1, - Fig. 3 a perspective view of an end piece for the tightener made of Fig. 1, and - Fig. 4 a top view of the end piece made of Fig. 3.

[0021] In Fig. Figure 1 shows a pyrotechnic tensioner 10 for a vehicle safety system. The pyrotechnic tensioner 10 serves, for example, to tighten a seat belt or to retract a gas bag out of the driver's field of vision after it has been triggered.

[0022] The tensioner 10 has a housing 12 in which a pressure chamber 14 is provided. A piston (not shown) is slidably mounted in the pressure chamber 14 in a tightening direction S. A pulling element connected to the safety system can be attached to this piston, which, in the event of triggering, is moved with the piston in the tightening direction S. This makes it possible, for example, to tighten a safety belt attached to the pulling element.

[0023] The housing 12 is closed by an end piece 16 in the opposite direction to the tightening direction S. The end piece 16 is made of plastic in one piece and is essentially L-shaped (see also Fig. 3 and Fig. 4), with a first section 18 and a second section 20.

[0024] The first section 18 serves as a front-end closure for the housing 12 or the pressure chamber 14.

[0025] The second section 20 forms, as shown below, the housing of a gas generator 22, through which an overpressure can be generated in the pressure chamber 14 in order to move the piston in the tightening direction S.

[0026] As in the Fig. 1 and Fig. As can be seen in Figure 2, a chamber 24 is provided in the second section 20, into which a propellant charge 26 can be filled. The walls of this section 20, i.e., the walls of the end piece 16, form the walls of the chamber 24 for the propellant charge or the propellant mixture of the gas generator 22.

[0027] In the embodiment shown here, chamber 24 is essentially cylindrical. However, the shape of chamber 24 can be adapted to the installation conditions in a vehicle as desired. In particular, chamber 24 does not have to be cylindrical.

[0028] Towards pressure chamber 14, this chamber 24 is fluidically closed off by a burst wall 28.

[0029] The burst wall 28 has several predetermined breaking points 30 through which the burst wall 28 can be opened in the event of triggering.

[0030] The opposite end of chamber 24 is closed by a detonator 32, into which a detonator plug can be inserted from the rear.

[0031] The first section 18 features a guide channel 34 for a tensioning element of the safety system, which is connected to the piston. The guide channel 34 extends longitudinally through the pressure chamber 14, or in the tensioning direction S, across the entire first section 18 of the end piece 16, thus enabling low-friction guidance of the tensioning element. The guide channel could also include deflection devices to redirect the tensioning element in a different direction.

[0032] Parallel to the guide channel 34, a gas guide channel 36 is provided at the end piece 16, extending from the rear of the rupture wall 28 into the pressure chamber 14. In the event of triggering, after the rupture wall has opened, this gas guide channel 36 establishes a flow connection between the chamber 24 for the propellant charge 26 and the pressure chamber 14.

[0033] In the event of a triggering event, the propellant charge 26 is ignited by the detonator 32 located in the plug receptacle 32. The overpressure generated in the chamber 24 opens the rupture wall 28, allowing the gas produced by the propellant charge 26 to flow from the chamber 24 into the pressure chamber 14 and move the piston in the tightening direction S.

[0034] Since the entire end piece 16 is manufactured in one piece, the number of components is significantly reduced. A separate housing for the gas generator is not required. This is formed by the walls of the end piece 16 or the second section 20 of the end piece 16.

[0035] Since the chamber 24 for the propellant charge 26 is completely closed on one side by the burst wall 28 and on the other side by the plug receptacle 32, the propellant charge 26 is safely protected from external influences, such as moisture.

[0036] The chamber 24 can be easily filled by closing it with the plug receptacle 32. The propellant charge 26 is filled into the chamber 24 before the detonator 32 is inserted, and the chamber is then closed with the detonator 32.

[0037] As in the Fig. 1 and Fig.As can be seen in Figure 2, the housing has 12 interconnected metal tubes 38 and 40 that enclose the first and second sections 18 and 20 of the end piece 16, respectively. These metal tubes 38 and 40 support the end piece 16.

[0038] The end piece 16 is preferably made of plastic, allowing for simple manufacturing, for example by injection molding. Since the gas generator 22 is permanently integrated into the end piece 16, additional fastening devices for attaching the gas generator to the housing are unnecessary.

[0039] The grooves 42 in the housing 12 and the crimped end 44 of the housing 12 ensure a secure positioning of the end piece 16 in the housing 12.

Claims

[1] Pyrotechnic tensioner (10) for a safety system in a vehicle, comprising a gas generator (22) having a propellant charge (26) and an igniter (32), and a housing (12) in which a pressure chamber (14) is provided into which the gas can flow and in which a piston can be moved in the tensioning direction by the gas, and a tension transmission means connected to the piston which extends longitudinally out of the pressure chamber (14), wherein an end piece (16) is provided on the housing (12) which closes the pressure chamber (14) in the opposite direction to the tensioning direction and in which a chamber (24) is provided into which the propellant charge (26) is filled and whose wall forms the wall of the propellant defined by the propellant charge (26), characterized by, that the end piece (16) is made of plastic and is at least partially enclosed by a metal tube (38), and that the pressure chamber (14) is closed by a plug receptacle (32) on the end face facing away from the traction transmission means. [2] Pyrotechnic tensioner according to claim 1, characterized by , that in the end piece (16) a gas guide channel (36) is provided which, in the event of triggering, fluidically connects the chamber (24) for the propellant charge (26) with the pressure chamber (14). [3] Pyrotechnical tensioner according to any of the preceding claims, characterized by , that a burst wall (28) is provided in the end piece (16) between the chamber (24) for the propellant charge (26) and the pressure chamber (14). [4] Pyrotechnical tensioner according to any of the preceding claims, characterized by , that a guide channel (34) for a pulling element of the safety system is provided at the end piece (16). [5] Pyrotechnical tensioner according to any of the preceding claims, characterized by , that the end piece (16) has a first section (18) in which the guide channel (34) and in particular the gas guide channel (36) is arranged, and a laterally projecting second section (20) in which the chamber (24) for the propellant charge (26) is arranged, in particular at right angles to the first section (18). [6] Pyrotechnical tensioner according to any of the preceding claims, characterized by , that a detonator (32) is provided at the end piece (16). [7] Pyrotechnic tensioner according to claim 6, characterized by , that the detonator (32) is provided on the second section (20) and in particular closes the chamber (24) for the propellant charge (26) of the gas generator (22). [8] Pyrotechnical tensioner according to any of the preceding claims, characterized by, that the detonator (32) is a prefabricated, self-contained component separated from the propellant charge by a detonator housing.

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