Gas generator with a gas reserve, for a protective device

Abstract

A gas generator comprising: - a gas chamber (10), including a discharge orifice (11), - a sealing cap (20), - inflation gases (30), stored in the gas chamber (10), - an opening piston (40), movable between a rest position and an open position, - a pyrotechnic device, arranged to move the opening piston (40), characterized in that the gas generator comprises: - at least one retaining element for the opening piston (40), provided to retain the opening piston (40) in the rest position before the pyrotechnic device is activated, and / or - at least one locking element for the opening piston (40) provided to, after the pyrotechnic device is activated, lock the opening piston (40) in the rest position or in an activated position. Figure for the abbreviation: Fig. 2

Description

Title of the invention: Gas generator with a gas reservoir, for a protective device Technical field of the invention

[0001] The present invention relates generally to gas generators and in particular to gas generators intended to equip a protective device, such as a protective device integrated into a vehicle (car, truck, two-wheeler, etc.) or as a personal protective device, for example: a motorcycle helmet (incorporating an inflatable cushion like an airbag), a cycling helmet (incorporating an inflatable cushion like an airbag), a hip protection belt (incorporating an inflatable cushion like an airbag), a motorcycle protective jacket (incorporating an inflatable cushion like an airbag)...

[0002] Typically, the gas generator according to the invention may include a reserve of gases stored under pressure, to quickly supply inflation gases to the protective device. State of the art

[0003] It is known, for example, from US patent 5653463, of a gas generator with a gas reservoir sealed by a sealing cap and an opening piston designed to break the sealing cap and ensure drainage of the gas reservoir. However, this system may have drawbacks regarding the repeatability of opening and draining, particularly due to the gas passage cross-section after opening, which may depend on the position of the opening piston. Description of the invention

[0004] One object of the present invention is to address the disadvantages of the prior art mentioned above and in particular, first of all, to propose a gas generator comprising a pressurized gas chamber, the operation of which is repeatable, in particular with regard to the opening of the gas chamber and its emptying after opening.

[0005] To this end, a first aspect of the invention relates to a gas generator for a user protection device, comprising: - a gas chamber, including a discharge orifice, - a sealing cap covering the discharge opening, - inflation gases, stored under pressure in the gas chamber sealed by the sealing cap, and intended to deploy the protective device after opening of the sealing cap, - an opening piston, arranged to be movable between a rest position and an open position, in which the movement of the opening piston from the rest position to the open position causes the sealing cap to open, - a pyrotechnic device, arranged to move the opening piston from the rest position to the open position, characterized in that the gas generator comprises: - at least one retaining element for the opening piston, designed to hold the opening piston in the rest position, at least before the pyrotechnic device is activated, and / or - at least one opening piston locking element designed to, after actuation of the pyrotechnic device, lock the opening piston in the rest position or in an activated position arranged between the open position and the rest position.

[0006] According to the above embodiment, the gas generator provides reproducible operation, because before and / or after the opening of the sealing cap, the position of the opening piston is well controlled: - before opening, the opening piston retaining element retains, locks, blocks, or holds the opening piston in the rest position, and / or - after opening, the opening piston locking element retains or locks or blocks or holds the opening piston in the rest position or in an activated position (arranged between the open position and the rest position).

[0007] Thus, before opening, the rest position of the opening piston is always the same, which guarantees that the movement will always begin from the same position, regardless of the operating conditions (whether brand new, or after a series of drops, shocks, or vibrations, for example). Similarly, after opening, the position of the opening piston is always the same (rest position or activated position), which guarantees a consistent passage cross-section and reproducible flow of pressurized gases.

[0008] After opening, it can be noted that the position of the opening piston is not the opening position, but either the rest position or the activated position (arranged between the opening position and the rest position), which means that the opening piston moves back once the sealing operculum is opened, to leave a large passage section and / or not to obstruct the discharge orifice: the emptying is rapid and not influenced by the section and / or dimensions of the opening piston.

[0009] According to one embodiment, the retaining element of the opening piston can be a mechanical retaining element and / or the locking element of the opening piston can be a mechanical locking element.

[0010] In particular: - the retaining element of the opening piston can be a reversible, elastic, flexible mechanical retaining element, free from plastic deformation, free from shear, which remains intact (the retaining element is free from material loss, the retaining element is free from tearing, the retaining element is free from separable parts) and / or - The opening piston locking element can be a reversible, elastic, flexible, plastic deformation-free, shear-free, mechanical locking element that remains intact (the locking element is free from material loss, the retaining element is free from tearing, and the retaining element has no separable parts). This absence of plastic deformation and / or material tearing ensures that no detached particles are released that could impair the movement of the opening piston and / or compromise the integrity of the safety device. In other words, the retaining element and / or the locking element can be designed to perform a coupling and / or uncoupling operation without plastic deformation and / or without tearing or cutting material from the parts involved.In particular, the movement of the opening piston during operation, from the rest position to the open position, can occur without plastic deformation and / or material tearing. Similarly, during operation, the recoil movement of the opening piston from the open position to the activated position or the rest position can occur without plastic deformation and / or material tearing. This does not preclude the possibility of plastic deformation of the retaining element and / or the locking element during the initial assembly of the gas generator (assembly of the opening piston in the rest position).

[0011] In one embodiment, the retaining element of the opening piston may be the same as the locking element of the opening piston; the retaining element of the opening piston may be identical to the locking element of the opening piston; the retaining element of the opening piston may have the same structure as the locking element of the opening piston. In one embodiment, the retaining element of the opening piston may be the locking element of the opening piston. This limits the number of elements formed on the opening piston, thereby optimizing cost and overall dimensions.

[0012] According to one embodiment, the gas generator may include at least one reference part, adjacent to the opening piston and such as an igniter support, or an igniter overmolded onto its support, or a containment casing, or even a combustion chamber, and the retaining element of the opening piston and / or the locking element of the The opening piston may include: - at least one male protrusion, such as a rib, arranged on one of the opening piston and the reference part, and / or - at least one female counterform, such as a groove, arranged on the other of the opening piston and the reference piece.

[0013] According to one embodiment, the gas generator may comprise: -at least one reference part, adjacent to the opening piston and such as a distributor support, - A first retaining element for the opening piston and / or a first locking element for the opening piston, formed by at least one male protrusion, such as a rib, arranged on one side of the opening piston and the reference part; - A second retaining element for the opening piston and / or a second locking element for the opening piston, formed by at least one female counterform, such as a groove, arranged on the other side of the opening piston and the reference part. A coupling may be provided between the first retaining element for the opening piston and the second retaining element for the opening piston to retain the opening piston in the rest position. A coupling may be provided between the first locking element for the opening piston and the second locking element for the opening piston to lock the opening piston in the rest position or in the activated position.

[0014] Particularly once the gas generator has been assembled, an elastic coupling, a reversible coupling, an elastic fit, or a clip can be provided between the male protrusion and the female counterform. In any case, the coupling and / or uncoupling between the male protrusion and the female counterform must be free from plastic deformation and / or material tearing. Such an absence of plastic deformation and / or material tearing ensures that no detached particles are detrimental to the movement of the opening piston and / or the integrity of the safety device. In other words, the male protrusion and the female counterform can be designed to perform a coupling and / or uncoupling operation without plastic deformation and / or without tearing or cutting material from the parts involved.In particular, the movement of the opening piston during operation, from the rest position to the open position, can occur without plastic deformation and / or material tearing. Similarly, during operation, the recoil movement of the opening piston from the open position to the activated position or the rest position can occur without plastic deformation and / or material tearing. This does not preclude the possibility of plastic deformation during the initial assembly of the gas generator (assembly of the opening piston in the rest position). opening piston and / or adjacent parts (especially when the male protrusion and / or female counterform are formed of metal).

[0015] According to one embodiment, at least one of the male protrusion and the female counterform may include a mating portion with the other of the male protrusion and the female counterform, the mating portion comprising a surface inclined at less than 35° and preferably less than 20° with respect to the direction of movement of the opening piston. In other words, at least one of the male protrusion and the female counterform may include a chamfer or an inclined portion to facilitate mating or unmating.

[0016] According to one embodiment, the male protrusion and / or the female counterform: - may exhibit asymmetry along the direction of movement of the opening piston, and / or - can be continuous or discontinuous or segmented in a direction transverse to the direction of movement of the opening piston.

[0017] According to one embodiment, the opening piston may include a side guide wall arranged to ensure guidance of the opening piston in the gas generator during movement between the rest position and the opening position, and the side guide wall has, in the direction of the movement of the opening piston between the rest position and the opening position, a guide length less than a characteristic dimension (typically a diameter) of the opening piston in a transverse direction of the movement of the opening piston between the rest position and the opening position.

[0018] According to one embodiment, the guide side wall has a continuous outer surface, typically a cylindrical surface with a circular base. This ensures flameless operation of the gas generator in accordance with the American standard SAE-USCAR24-2 April 2013, paragraph 3.2.4, "inflator flaming." In other words, the guide side wall is free of segments, bosses, or seals.

[0019] According to one embodiment, the opening piston can be cylindrical, for example with a circular cross-section.

[0020] According to one embodiment, the opening piston may include a central recess and / or an internal bore, and the opening piston retaining element and / or the opening piston locking element may be arranged in the central recess and / or the internal bore. In other words, the opening piston retaining element and / or the opening piston locking element may be separate and / or distinct from the side wall, i.e., the opening piston retaining element and / or the opening piston locking element may be separate and / or distinct from the external surface of the opening piston.

[0021] According to one embodiment, the guide wall has a clearance with the gas generator at a radius less than or equal to 0.075 mm, advantageously less than or equal to 0.05 mm.

[0022] According to one embodiment, the guide wall may be free of an opening piston retaining element and / or an opening piston locking element and / or sealing means. Thus, the opening piston retaining element and / or the opening piston locking element do not affect the guidance of the opening piston during its movement.

[0023] According to one embodiment, the pyrotechnic device may include an electro-pyrotechnic igniter, and wherein the gas generator may include a containment sleeve arranged around the electro-pyrotechnic igniter and / or at least partially between the opening piston and the electro-pyrotechnic igniter. Typically, the containment sleeve is a separate part from the electro-pyrotechnic igniter, which allows the use of a standardized electro-pyrotechnic igniter in the gas generator.

[0024] According to one embodiment, the containment casing may include a filtration portion arranged at least partially between the opening piston and the electro-pyrotechnic igniter. The filtration portion may typically be a wall with passage holes, and / or a grid.

[0025] According to one embodiment, the electro-pyrotechnic igniter may comprise: - a pyrotechnic material, - a loading case, containing the pyrotechnic material and designed to detach after the pyrotechnic material has been ignited, - an electrical insulating cap, for example a plastic cap, covering the loading case. The loading case may be metallic with areas of intended weakness to allow for petaling during operation. Typically, pieces of the loading case and / or the electrical insulating cap may break off. The filter portion can stop this debris, allowing reliable movement of the opening piston (even with a return or recoil from the open position) which might otherwise be slowed or blocked by particles generated during the operation of the electro-pyrotechnic igniter.

[0026] A second aspect of the invention may relate to a protective device integrated into a vehicle (car, truck, two-wheeler, etc.) or a user's device, comprising at least one gas generator according to the first aspect of the invention. Examples include a motorcycle helmet (incorporating an inflatable cushion such as an airbag), a bicycle helmet (incorporating an inflatable cushion such as an airbag), a hip belt (incorporating an inflatable cushion such as an airbag), a motorcycle protective jacket (incorporating an inflatable cushion such as an airbag), and a safety harness. (incorporating an inflatable cushion like an airbag), a ski vest (incorporating an inflatable cushion like an airbag). In particular, the invention may relate to a gas generator whose operation does not generate any visible flame during its operation (for example, according to the American standard SAE-USCAR24-2 April 2013, paragraph 3.2.4 "inflator flaming"); in other words, the invention may relate to a generator whose pyrotechnic combustion generated by the electro-pyrotechnic igniter remains confined within the generator. Description of the figures

[0027] Other features and advantages of the present invention will become more apparent upon reading the following detailed description of an embodiment of the invention given by way of non-limiting example and illustrated by the accompanying drawings, in which:

[0028] [Fig. 1] represents a cross-sectional view of a gas generator before operation;

[0029] [Fig.2] represents a detail of the cross-sectional view of [Fig.1];

[0030] [Fig.3] represents the gas generator of [Fig.1] in operation;

[0031] [Fig.4] represents the gas generator of [Fig.1] after operation.

[0032] Detailed description of embodiment(s)

[0033] Figure 1 represents a gas generator user / occupant protection device, comprising: - a gas chamber 10, comprising a discharge orifice 11, - a sealing cap 20 sealing the discharge orifice 11, - inflation gases 30, stored under pressure in the gas chamber 10 sealed by the sealing cap 11, and intended to deploy the protective device after opening the sealing cap 20, - a piston with an opening of 40, arranged in a rest position, - a pyrotechnic device formed in this example of [Fig.1] by an electro-pyrotechnic igniter 50.

[0034] In this example, the gas chamber 10 is formed by an assembly of several parts: - a chamber body 12, - a base part 60 which has a bottom with the discharge orifice 11, welded onto the chamber body 12, - a plug 14 also welded onto the chamber body 12. The gas chamber 10 also includes, near the discharge orifice 11, a regulating nozzle 13, provided with an orifice of smaller cross-section than that of the discharge orifice 11.

[0035] The discharge orifice is sealed or plugged by a sealing cap 20 which may be a thin metal piece (stainless steel or Inconel) welded to the bottom of the base part 60.

[0036] The inflation gases 30 can be stored at a pressure between 20 MPa and 70 MPa and can include inert gases, such as argon and helium. However, other gases may be considered.

[0037] The opening piston 40 is a movable part between the rest position ([Fig. 1] or 4) and an open position (shown [Fig. 3]), and includes a tip 41, such that the movement of the opening piston 40 from the rest position to the open position causes the sealing disc 20 to open. For this purpose, the lateral or external wall of the opening piston 40 can be provided to form a guide wall in the base part 60, and a clearance of between 0.02 mm and 0.1 mm can be provided at the radius (a clearance of 0.075 mm can be provided, advantageously a clearance less than or equal to 0.05 mm at the radius). With such clearances, a guide length shorter than the diameter of the opening piston can be provided, to ensure a small axial footprint.

[0038] The opening piston 40 can preferably be formed in metal, but a part made of plastic, or even a composite part, can be provided.

[0039] The electro-pyrotechnic igniter 50 is fixed to an igniter support 52 with a seal 51, and is covered by a containment sleeve 53 having a perforated wall arranged between the electro-pyrotechnic igniter 50 and the opening piston 40. The containment sleeve 53 can generally be metallic, but a plastic part resistant to the operation of the electro-pyrotechnic igniter 50 can be considered.

[0040] The electro-pyrotechnic igniter 50 typically comprises: - a resistive bridge, - a pyrotechnic material that can ignite when an electric ignition current passes through the resistive bridge, - a containment casing, usually metallic (but a plastic one could be considered), containing the pyrotechnic material. - an electrical insulation cap covering the charging case. The electro-pyrotechnic igniter 50 is arranged to move the opening piston 40 from the rest position to the opening position by generating hot combustion gases which push the opening piston to the right of the [Fig.1].

[0041] The base piece 60 has a central bore which opens onto the discharge orifice and which contains the opening piston 40, and the electro-pyrotechnic igniter 50 fixed on the igniter support 52, the latter being crimped onto the base piece 60. Diffusion holes 61 are provided on the base piece 60.

[0042] [Fig. 2] represents a detail II of [Fig. 1], to show a retaining element for the opening piston 40 in the rest position and / or a locking element for the opening piston 40 in the open position. As explained above, the The opening piston 40 occupies a rest position before the gas generator is activated. To ensure this rest position before activation, the opening piston 40 is equipped with a groove 42 and the igniter support 52 with a boss 521.

[0043] It can also be noted that: - the opening piston 40 may also include an inlet chamfer 44, with an angle Al relative to the axial direction of the gas generator (or the direction of movement of the opening piston 40), the angle Al being within a range of values ​​from 5° to 30°, and preferably from 15° to 25°, - boss 521 and groove 42 can be asymmetrical, - the boss 521 may have an inlet slope 522 with an angle A2 relative to the axial direction of the gas generator (or the direction of movement of the opening piston 40), the angle A2 being within a range of values ​​from 5° to 30°, and preferably from 15° to 25°, - the groove 42 may have an outlet slope 44 with an angle A3 relative to the axial direction of the gas generator (or the direction of movement of the opening piston 40), the angle A3 being within a range of values ​​from 25° to 45°, and preferably from 30° to 45°, - the opening piston 40 may include an external constriction 43, which may extend to the face or height of the groove 42 to facilitate positioning and release of the piston from the rest position.

[0044] In [Fig. 2], the groove 42 receives the boss 521 when the opening piston 40 is in the rest position of [Fig. 1]. Since the inlet diameter of the central bore of the opening piston 40 is smaller than the diameter of the boss 521, the opening piston 40 cannot move freely and it can be considered that: - the boss 521 forms a retaining element for the opening piston 40 to hold the opening piston 40 in the rest position, or - the groove 42 forms a retaining element for the opening piston 40 to hold the opening piston 40 in the rest position, or - the boss 521 forms a first retaining element 71 of the opening piston 40, and the groove 42 forms a second retaining element 72 of the opening piston 40, to retain the opening piston 40 in the rest position.

[0045] However, the inlet diameter of the central bore of the opening piston 40 can be less than the diameter of the boss 521 by an interference value of less than 0.1 mm, or even less than 0.05 mm (to the diameter), so that the opening piston 40, under a thrust force, can be released from the rest position to go into an open position.

[0046] As shown in [Fig. 3], the electro-pyrotechnic igniter 50 was ignited to generate combustion gases in the central bore of the opening piston 40, and the latter has moved to the right of [Fig.3] until it comes to rest against the bottom of the base piece 60, so that the tip 41 pierces the sealing operculum 20. The regulating nozzle 13 includes a central boss to avoid any interference with the tip 41 when the opening piston 40 is in the open position of [Fig.2].

[0047] It can therefore be noted that the electro-pyrotechnic igniter 50 generated sufficient combustion gases to produce a thrust force on the opening piston greater than the retaining force exerted by the coupling of the boss 521 in the groove 42. It can be noted that the disengagement is preferably elastic and / or reversible, and / or is carried out without plastic deformation or material tearing on the parts involved. This allows the retaining element to be used as a locking element.

[0048] It can also be noted that the containment case 53, with its perforated distal wall, retains fragments that could have detached from the electro-pyrotechnic igniter 50 (pieces of plastic insulating cap, pieces of a metal case, or even pieces of pyrotechnic material) and also prevents swelling of the loading case of the electro-pyrotechnic igniter 50 during operation from hindering the movement of the opening piston 40, so that the space between the containment case 53 and the opening piston 40 or the base piece 60 (and in particular the central bore of the opening piston 40 and the exposed part of the internal bore of the base piece 60) remains relatively clean and / or free of solid particles that could affect the movement of the opening piston 40.

[0049] Consequently, the opening piston 40 slid thanks to the guidance of its lateral wall in the base piece 60, and this guidance remains functional after operation thanks to the filtration provided by the containment sleeve, so that it can be guaranteed that the opening piston retracts once it has reached the open position of [Fig. 2]. This retraction of the opening piston 40 allows the discharge orifice 11 to be freed to ensure good repeatability from one gas generator to another of the passage area of ​​the gases stored in the gas chamber 10.

[0050] As shown in [Fig. 4], the opening piston 40 can therefore recoil, as in the example shown in [Fig. 4], to return to the rest position of [Fig. 1]. However, it is possible to stop the recoil of the opening piston in an activated position arranged between the rest position of [Fig. 1] and the open position of [Fig. 3].

[0051] The opening piston, having returned to the rest position, is then locked in this rest position by the groove 42 which receives the boss 521. As in the situation of [Fig.2] before operation, the groove 42 receives the boss 521 when the opening piston 40 is in the rest position of [Fig.4], after operation. Since the inlet diameter of the central bore of the opening piston 40 is smaller than the diameter of the boss 521, the opening piston 40 can no longer move freely and we can consider that: - the boss 521 forms a locking element for the opening piston 40 to retain the opening piston 40 in the rest position, or - the groove 42 forms a locking element for the opening piston 40 to retain the opening piston 40 in the rest position, or - the boss 521 forms a first locking element (identical to the first retaining element 71) of the opening piston 40, and the groove 42 forms a second locking element (identical to the second retaining element 72) of the opening piston 40, to retain the opening piston 40 in the rest position.

[0052] As a result, the opening piston 40 is securely locked in the rest position after operation, so that the inflation gases can be released repeatedly towards the diffusion holes 61 of the base part 60, as shown by the arrows in [Fig.4].

[0053] In general, the following points can be noted: - Retaining the opening piston 40 in its rest position before operation ensures that the movement to the opening position always starts from the same position, thus improving reproducibility. - the filtration or screening function provided by the containment casing 53 ensures a repeatable and reliable recoil of the opening piston; it can also be noted that less debris can be ejected from the gas generator without having provided a sealing gasket (which would also be detrimental to the free movement of the opening piston 40), - the recoil of the opening piston 40 after the opening of the sealing operculum provides a repeatable flow of gases from the gas chamber 10, always through the same passage section, - The regulating nozzle 13 can be easily adjusted to regulate the flow rate as required for one application or another, without changing the opening mechanism. - Locking the opening piston 40 in a retracted, activated or rest position further contributes to increasing the repeatability of operation, by eliminating any risk of rebound, oscillation, back and forth movement of the opening piston 40 during the complete emptying of the gas chamber 10.

[0054] In the example of [Fig.4], the locking element (or elements) is identical to the retaining element (or elements), but separate elements or parts can be considered.

[0055] In the example of [Fig.2], a groove 42 and a boss 521 are shown, but flexible tabs, parts intended to be clamped, tongues, i.e. any type of elastic retention and / or locking means, can be provided. reversible, and preferably without plastic or irreversible deformation, detachment of parts, or breakage, particularly during operation. Furthermore, the retaining and / or locking element may extend over 360° or may be segmented or point-like. Industrial application

[0056] A gas generator according to the present invention, and its manufacture, are capable of industrial application.

[0057] It will be understood that various modifications and / or improvements obvious to a person skilled in the art can be made to the different embodiments of the invention described in this description without departing from the scope of the invention.

Claims

Claims

1. Gas generator for a user protection device, comprising: - a gas chamber (10), comprising a discharge orifice (11), - a sealing cap (20) sealing the discharge orifice (11), - inflation gases (30), stored under pressure in the gas chamber (10) sealed by the sealing cap (20), and provided to deploy the protection device after opening of the sealing cap (20), - an opening piston (40), arranged to be movable between a rest position, and an open position, in which the movement of the opening piston (40) from the rest position to the open position causes the opening of the sealing cap (20), - a pyrotechnic device, arranged to move the opening piston (40) from the rest position to the opening position, characterized in that the gas generator comprises: - at least one opening piston retaining element (40), provided for retaining the opening piston (40) in the rest position, at least before actuation of the pyrotechnic device, and / or - at least one opening piston locking element (40) provided to, after actuation of the pyrotechnic device, lock the opening piston (40) in the rest position or in an activated position arranged between the open position and the rest position, and in that the gas generator comprises at least one reference part, adjacent to the opening piston (40) and such as an igniter support (52), wherein the opening piston retaining element (40) and / or the opening piston locking element (40) comprises: - at least one male protrusion, such as a rib, arranged on one of the opening piston (40) and the reference part, and / or - at least one female counterform, such as a groove (43), arranged on the other of the opening piston (40) and the reference part, and wherein a coupling between the male protrusion and the female counterform is elastic and reversible.

2. A gas generator according to claim 1, wherein the retaining element of the opening piston (40) is a mechanical retaining element and / or the locking element of the opening piston (40) is a mechanical locking element.

3. A gas generator according to claim 1 or 2, wherein at least one of the male protrusion and the female counterform comprises a coupling portion with the other of the male protrusion and the female counterform, the coupling portion comprising a surface inclined at less than 35° and preferably at less than 20° relative to the direction of movement of the opening piston (40).

4. Gas generator according to one of claims 1 to 3, in which the male protuberance and / or the female counterform: - has an asymmetry along the direction of movement of the opening piston (40), and / or - is continuous or discontinuous or segmented in a direction transverse to the direction of movement of the opening piston (40).

5. A gas generator according to one of claims 1 to 4, wherein the opening piston (40) comprises a guide side wall arranged to provide guidance of the opening piston (40) in the gas generator during movement between the rest position and the open position, and wherein the guide side wall has, in the direction of movement of the opening piston (40) between the rest position and the open position, a guide length less than a characteristic dimension of the opening piston (40) in a transverse direction of movement of the opening piston (40) between the rest position and the open position.

6. Gas generator according to claim 5, in which the guide wall has with the gas generator a clearance at the radius less than or equal to 0.075 mm, advantageously less than or equal to 0.05 mm.

7. Gas generator according to one of claims 5 or 6, wherein the guide wall is free of an opening piston retaining element (40) and / or an opening piston locking element (40) and / or sealing means.

8. A gas generator according to one of claims 1 to 7, wherein the pyrotechnic device comprises an electro-pyrotechnic igniter (50), and wherein the gas generator comprises a containment case (53) arranged around the electro-pyrotechnic igniter (50) and / or at least partially between the opening piston (40) and the electro-pyrotechnic igniter (50).

9. A gas generator according to claim 8, wherein the containment case (53) comprises a filtration portion arranged at least partially between the opening piston (40) and the electro-igniter. pyrotechnics (50).

10. Gas generator according to one of claims 8 or 9, in which the electro-pyrotechnic igniter (50) comprises: - a pyrotechnic material, - a charging case, containing the pyrotechnic material and designed to uncap after ignition of the pyrotechnic material, - an electrically insulating cap, for example a plastic cap, covering the charging case.

11. Device for protecting a user, comprising at least one gas generator according to one of claims 1 to 10.

Images