阅读说明：本技术 气囊模块和气囊系统 (Airbag module and airbag system ) 是由 M·布勒克 C·奥姆勒 于 2019-03-21 设计创作，主要内容包括：本发明涉及一种气囊模块(16)以及具有这种气囊模块(16)的气囊系统(18),其中,气囊模块(16)具有气囊袋(22)和气体发生器(30),在气囊袋和气体发生器之间设置有带有阀装置(34)的气体输入装置(32),其中,阀装置(34)具有可电控的导向阀(36)和用于增大导向阀(36)的提升作用的液压传动装置(52)。(The invention relates to an airbag module (16) and an airbag system (18) having such an airbag module (16), wherein the airbag module (16) has an airbag (22) and a gas generator (30), between which a gas supply device (32) having a valve device (34) is arranged, wherein the valve device (34) has an electrically controllable pilot valve (36) and a hydraulic drive (52) for increasing the lifting action of the pilot valve (36).)

1. An airbag module (16) having:

-an airbag (22) which, in operation, is filled with pressurized airbag gas (24);

-a gas generator (30) for providing pressurized airbag gas (24); and

-gas input means (32) between the gas generator (30) and the airbag (22) for inputting pressurized airbag gas (24) provided by the gas generator (30) into the airbag (22);

wherein a valve device (34) is provided in the gas supply device (32) for releasing a predefined mass flow of the pressurized airbag gas (24) from the gas generator (30)

Wherein the valve device (34) is provided with a valve for controlling the air of the air bagPredefined mass flow of the body (24)And a hydraulic drive (52) for increasing the lifting action of the pilot valve (36).

2. The airbag module (16) of claim 1,

characterized in that the hydraulic drive (52) has a control chamber (58) which is fluidically connected to the gas generator (30) via a connecting opening (60) and via a throttle opening (62) which is arranged separately from the connecting opening (60) and which is fluidically connected to the airbag (22) via a vent opening (64), wherein a closing means (66) is arranged in the control chamber (58) for closing and releasing a valve seat (68) in the connecting opening (60) or in the vent opening (64), wherein the closing means (66) is designed as a separating means (70) which separates the control chamber (58) into a first control chamber region (72) and a second control chamber region (74) which is separate from the first control chamber (58).

3. The airbag module (16) of claim 2,

characterized in that the throttle bore (62) fluidically connects the first control chamber region (72) to the gas generator (30), wherein the pilot valve (36) is designed to control a fluid pressure (P) of the airbag gas (24) in the first control chamber region (72)_F)。

4. The airbag module (16) of any of claims 2 or 3,

characterized in that the inlet opening (56) to the pilot valve (36) forms a fluid connection of the control chamber (58) to the pilot valve (36), wherein the outlet opening (78) of the pilot valve forms a fluid connection of the pilot valve (36) to the airbag (22).

5. The airbag module (16) of any of claims 2 to 4,

characterized in that the connecting bore (60) connects the gas generator (30) to the second control chamber region (74).

6. The airbag module (16) of any of claims 2 to 5,

characterized in that the closing means (66) is designed such that a first pressure application surface (A) acting on the closing means (66) from the side of the first control chamber region (72) is provided₁) Is larger than a second pressure acting surface (A) from the connecting hole side when the valve seat (68) is designed in the connecting hole (60)₂) Or from a second pressure-acting surface (A) on the drain opening side when the valve seat (68) is arranged in the drain opening (64)₂)。

7. The airbag module (16) of any of claims 1 to 6,

characterized in that the pilot valve (36) is designed as a non-energized normally closed pilot valve (36) and has a pressure spring (54) which pretensions the pilot valve means (40) in a closed position (66) against a pilot valve seat (42) in the inlet opening (56), wherein the pressure spring (54) in particular pretensions an opening pressure (P) of the pilot valve (36)_Open) Is defined such that the opening pressure (P)_Open) A high pressure (P) greater than the gas pressure (P) of the airbag gas (24) that is filled in the gas generator (30) by activating the gas generator (30)_H)。

8. The airbag module (16) of any of claims 1 to 6,

the pilot valve (36) is designed as a non-energized normally open pilot valve (36) and has a pressure spring (54) which pretensions the pilot valve means (40) in a defined open position.

9. An airbag system (18) having:

-an airbag module (16) according to any one of claims 1 to 8; and

-a control device (28) for controlling the pilot valve (36), wherein the control device (28) is provided for recognizing a collision process and for defining the supply of air to the airbag (22) on the basis of the recognized collision processOf the airbag gas (24)

Technical Field

The present invention relates to an airbag module and an airbag system which usually form part of a restraint system for a passenger belt in a motor vehicle.

Background

Nowadays, airbag systems together with safety belts constitute the most important passive safety component in passenger belt retractor systems in motor vehicles in order to prevent serious injury to the passenger in the event of a collision of the motor vehicle with an obstacle.

Airbag systems mostly have a plurality of airbag modules, each of which comprises at least one airbag, which is filled with airbag gas in the event of a crash. Meanwhile, in a very short time range between 10 milliseconds and 50 milliseconds, the airbag is deployed between the occupant and the interior space portion of the motor vehicle and constitutes a cushion. This prevents the occupant from hitting a hard part of the interior space, such as the steering wheel or the instrument panel.

The airbag gas is supplied in the gas generator at a high pressure of between 50 bar and 1000 bar. The gas generator may be a hot gas generator (pyrotechnical gas generator), a cold gas generator or also a mixed gas generator.

The airbag system also has at least one sensor which can be used to detect the impact time t in the event of a collision₀And (6) detecting. At the collision time t₀After a certain time (in the millisecond range) the airbag starts to be triggered. For this purpose, the airbag module has a gas generator which supplies the airbag gas for filling the airbag. The airbag gas may be provided, for example, by igniting a solid fuel that releases the airbag gas upon combustion, or by a gas stored at high pressure. The airbag gas supplied from the gas generator flows into the airbag, fills it and deploys it.

At the time of impact t of the current airbag system₀Triggered shortly thereafter, i.e. after a collision has occurred. However, in future airbag systems, it is planned to identify the points in time t at which a collision cannot be avoided by suitable sensors and evaluation of the sensor signals by analysis_n. The time point t_nAt the actual point in time t of the collision₀The so-called pre-crash phase before. This information is intended to be used to activate the airbag system as early as before the collision, so that the vehicle occupant can be better protected from injury.

Hitherto, it has been proposed to use two-stage airbag modules, in which two gas generators which are triggered at different times are provided in advance. In this case, a constant mass flow is respectively provided in two successive stagesThe airbag gas of (a) is introduced into the airbag.

Disclosure of Invention

The object of the invention is to provide an airbag module for an airbag system which is further improved.

This object is achieved by an airbag module having the combination of features of claim 1.

An airbag system with such an airbag module is the subject of the independent claim.

Advantageous embodiments of the invention are the subject of the dependent claims.

The airbag module has an airbag which is filled with pressurized airbag gas during operation; the airbag module also has a gas generator for providing pressurized airbag gas to the airbag. The airbag module also has a gas feed between the gas generator and the airbag for feeding pressurized airbag gas supplied by the gas generator into the airbag. Valve means are provided in the gas supply device for releasing a predefined mass flow of pressurized airbag gas from the gas generator

Here, the mass flow of the airbag gasDefined by the mass (m/t) flowing to the bag per unit time.

The valve device has a predefined mass flow for controlling the gas of the airbagAnd a pilot valve (pilotpilot) for increasing the pilotHydraulic means for the lifting action of the valve.

By providing a valve device which can be controlled in a targeted manner and is electrically actuated in the gas supply between the gas generator and the airbag, the filling of the airbag with airbag gas can be adapted specifically to the collision process. To enable an optimum filling process of the airbag, for example by completely filling the airbag before the expected collision and then refilling it, a mass flow of airbag gas to the gas generator is requiredAnd (5) controlling. In the previously known airbag systems in which the two gas generators are triggered at staggered times, a constant mass flow can only be generated in the airbag pocketBut not to mass flowAnd performing targeted control. By providing the valve device only with an electrically controllable pilot valve, it is possible to specifically control the mass flow rate by the valve device at any time before, during and after the collisionControls and thereby adjusts the filling of the airbag at any point in time. This enables the filling of the airbag to be adapted specifically to the crash process.

In principle, the filling of the airbag can already be actively controlled, for example, by means of a separate electrically controllable valve, for example, a solenoid valve. However, if solenoid valves are used, the size and weight of the magnets used lead to a certain inertia of the system and also to a relatively large installation space. In the present case, therefore, only a small, electrically controllable pilot valve is used, which can be designed, for example, as a solenoid valve. Here, only one small magnet is required, since in addition to the mass flow, this is responsibleIn addition to the actual controlled pilot valve itself, a hydraulic transmission is provided which doubles the actual lift of the pilot valve. Thus, the required mass is set by the hydraulic transmission without using very large magnets, and the mass flow is setIs controlled by an electrically controllable pilot valve.

The hydraulic drive advantageously has a control chamber which is in fluid connection with the gas generator via a connection opening and via an orifice which is arranged separately from the connection opening. In addition, the control chamber is fluidly connected to the airbag through a vent hole. In the control chamber, a closing means is provided for closing and releasing the valve seat in the connecting bore or in the drain bore. The closing means are designed as separating means which divide the control chamber into a first control chamber region and a second control chamber region which is separate from the first control chamber region.

The throttle bore connects the first control chamber region in a fluid-conducting manner to the gas generator, wherein the pilot valve is designed to control the fluid pressure of the airbag gas in the first control chamber region.

The closing means are arranged as separating means between the first control chamber region and the second control chamber region. This means that static fluid pressure acts on the closure element both from the first control chamber region side and from the second control chamber region side. If the system is in a state of pressure equilibrium, the closure device does not move but remains in its initial position. However, if the pressure applied from the first control chamber area side is different from the pressure applied from the second control chamber area side, the closing means moves to the open or closed position according to the setting of the two control chamber areas. In the open position, the closure device releases the gas inlet means and the airbag gas can flow from the gas generator into the airbag. In the closed position, however, the closure means close off the gas supply device, so that no airbag gas flows from the gas generator into the airbag.

The fluid pressure prevailing on the first control chamber area side is controlled by means of a pilot valve. The pilot valve has a pilot valve closing means which closes the inlet opening to the pilot valve. The pilot valve is in a favorable manner fluidically connected to the control chamber, in particular to the first control chamber region, via the inlet opening. When the pilot valve is open, the airbag gas can flow out of the first control chamber region through the pilot valve, the fluid pressure in the first control chamber region drops, and the fluid pressure acting on the closure means from the second control chamber region is greater than the fluid pressure acting on the closure means from the first control chamber region. The closure element thus changes its position, in particular moves into the open position, and the airbag gas flows from the gas generator into the airbag.

The guide valve also advantageously has a vent opening which forms a fluid connection of the guide valve to the airbag. Thus, the airbag gas also flows from the first control chamber region to the airbag through the inlet opening and the outlet opening of the guide valve.

The connection opening connecting the gas generator to the control chamber region connects the gas generator, in particular, to the second control chamber region.

The closing means is advantageously designed in such a way that a first pressure application surface acting on the closing means from the first control chamber region side is greater than a second pressure application surface from the connection opening side when the valve seat is designed in the connection opening or from the drain opening side when the valve seat is designed in the drain opening.

Accordingly, the closure means can be designed such that, when the closure means is in the valve seat, the closure means closes off a vent opening to the airbag or the closure means closes off a connection opening between the control chamber and the gas generator.

The closing means are preferably designed as spheres, but it is also possible to design the closing means as cones, for example. In this case, it is only important that the pressure-acting surfaces on the first control chamber region side and on the second control chamber region side differ, so that a movement of the closure element can be brought about by a pressure change in the two control chamber regions.

The diameter of the throttle bore allows the fluid pressure prevailing in the first control chamber region to be set in comparison with the fluid pressure prevailing in the second control chamber region. The fluid pressure prevailing in the first control chamber region can thus be kept slightly below the switching pressure, i.e. the state of the valve device in which the closure means starts to move, or slightly above the switching pressure. In this respect, the diameter of the inlet opening to the pilot valve can also be adjusted in order to influence the existing fluid pressure.

The pilot valve is preferably designed as a non-energized normally closed pilot valve and has a pressure spring which biases the pilot valve device into the closed position against a pilot valve seat in the inlet opening, wherein the pressure spring in particular defines an opening pressure of the pilot valve such that the opening pressure is greater than a high pressure of the gas bag which is filled in the gas generator by activating the gas generator. This advantageously prevents the pilot valve from being opened accidentally, thereby activating the entire valve device.

Alternatively, however, the pilot valve can also be designed as an unpowered, normally open pilot valve. The pilot valve is actively kept closed by energization and is opened only after the current is turned off. For this purpose, the pressure spring is advantageously provided to bias the pilot valve in a defined open position.

The airbag system has an airbag module as described above, and furthermore a control device for actuating the pilot valve, wherein the control device is provided for detecting a crash process and for defining a mass flow of the airbag gas to be supplied to the airbag on the basis of the detected crash process

In addition, the airbag system advantageously has at least one sensor which detects a parameter for calculating the expected crash course before the time of the crash and transmits it to the control device.

For this purpose, the control device is preferably provided for defining the expected crash course from the detected parameters and, on the basis thereof, the required mass of airbag gas in the airbag at each point in time of the crash course.

The unavoidable times of a collision, for example the time t at which the collision occurred, can therefore be identified by the parameters detected by the sensors_nWhich forces are expected in a collision and from this it is concluded to which degree the airbag must be filled with gas in order to avoid injury to the occupant.

For this purpose, it is advantageous to detect not only the vehicle speed and the distance to the obstacle, but also occupant characteristics, such as height and weight, so that the airbag can be activated by means of occupant parameters.

For example, the control device is provided for controlling the pilot valve in such a way that the pilot valve releases a plurality of defined components of the required gas mass of the airbag from the gas generator at different points in time during the crash. For example, the pilot valve may release a fraction of the airbag gas into the airbag already before the intended collision, so that the airbag is already pre-filled. Further, it is also possible to fill the airbag with another amount of airbag gas during a collision and, after the actual collision, to supplement the filling of the airbag with another amount of airbag gas if the occupant delays reacting to a negative acceleration due to inertia.

Drawings

The advantageous embodiments of the invention are explained in detail below with reference to the drawings. Wherein:

fig. 1 this is a schematic top view of a motor vehicle approaching an obstacle along a time axis t;

FIG. 2 is a diagram of the time t at which the vehicle shown in FIG. 1 collides with an obstacle when the airbag module is activated in the vehicle interior₀Instantaneous photography of (2);

FIG. 3 is a schematic longitudinal cross-sectional view of a first embodiment of the airbag module shown in FIG. 2 with a valve arrangement, in which the pilot valve is designed as an electrically non-closing pilot valve;

FIG. 4 is a detail view of the hydraulic transmission for the pilot valve of FIG. 3;

FIG. 5 is a schematic longitudinal cross-sectional view of the valve assembly of FIG. 3, wherein the pilot valve is configured as a non-energized normally open pilot valve;

FIG. 6 is a schematic longitudinal cross-sectional view of a second embodiment of the airbag module of FIG. 2 with a valve arrangement, in which the pilot valve is designed as an unpowered normally closed pilot valve;

FIG. 7 is a detail view of the hydraulic transmission for the pilot valve of FIG. 6; and

fig. 8 is a schematic longitudinal sectional view of the valve device shown in fig. 6, wherein the pilot valve is designed as a non-energized normally open pilot valve.

Detailed Description

Fig. 1 shows a schematic top view of a motor vehicle 10 approaching an obstacle 12 and having a high probability of collision with the obstacle. The approach procedure is displayed in time according to a time axis with a time distribution t, wherein t₀A collision time point, i.e. a time point at which the motor vehicle 10 contacts the obstacle 12, is defined.

The motor vehicle 10 has a sensor 14 that detects the speed of the motor vehicle 10 and the distance to the obstacle 12. The speed and distance are parameters detected before the expected collision time, from which the expected collision course can be calculated.

FIG. 2 shows the point of impact time t₀Instantaneous photography of the interior (top view) and exterior (bottom view) of the motor vehicle 10 of fig. 1.

In the interior view it can be seen that the instant photography of the airbag module 16 of the airbag system 18 in the motor vehicle 10 is activated when the motor vehicle 10 collides with an obstacle 12 as shown in the exterior view of the motor vehicle 10.

To protect an occupant 20 in the motor vehicle 10 from injury, an airbag 22 of the airbag module 16 is filled with airbag gas 24, which deploys and separates the occupant 20 from the hard components of the motor vehicle 10. Thereby preventing injury to the occupant 20.

A further sensor 26 is provided in the motor vehicle 10, which detects characteristics of the occupant 20, such as his height and weight.

Based on the parameters detected by the sensors 14, 26, it is possible to calculate in advance the crash course of the unavoidable crash situation and to determine at which predetermined point in time t_nAir bag22 must be inflated to the extent that maximum protection is provided to the occupant 20.

For this purpose, the control device 28 detects the signals of the sensors 14, 26 and determines the expected crash course from these signals. Thereby, the control device 28 can define what mass flow rate has to be adjustedIs input into the airbag 22.

In order to be able to fill the airbag 22 in a targeted manner in accordance with the expected crash process, a special airbag module 16 is provided, which is shown schematically in longitudinal section in fig. 3 to 8.

A first embodiment of the airbag module 16 will be described with reference to fig. 3. In addition to the airbag 22, the airbag module 16 also has a gas generator 30 which supplies the airbag 22 with the airbag gas 24. Here, the airbag gas 24 can be supplied by a cold gas generator and thus be present in the gaseous state from the beginning. However, a pyrotechnic gas generator 30 may also be used in which a solid fuel is present in the gas generator 30 that is first ignited to release the airbag gases 24 if desired.

A gas feed 32 is arranged between the airbag 22 and the gas generator 28, via which gas feed the airbag gas 24 can be conducted from the gas generator 30 to the airbag 22.

In the gas supply 32, a valve device 34 is provided, which has an electrically controllable pilot valve 36, which can be controlled in a targeted manner via the control device 28, so that the gas supply 32 can be opened or closed in a targeted manner. Thereby, the mass flow rate of the airbag gas 24 input from the gas generator 30 to the airbag 22Can be controlled in a targeted manner in a predefined manner.

The pilot valve 36 has a valve region 38 in which a pilot valve means 40 cooperates with a pilot valve seat 42 in order to hold the pilot valve 36 in the closed position.

The pilot valve 36 also has an actuator region 44 which, in the electrically controlled state, exerts a movement force B on the pilot valve means 40, so that the pilot valve means 40 is moved between its closed position and its open position.

The actuator region 44 has magnetic means, such as a fixed pole piece (polsky) 46 and a movable armature 48, the armature 48 being coupled to the pilot valve means 40. In addition, the armature 48 transmits its movement to the pilot valve device 40. To induce movement of the armature 48, the actuator region 44 includes a coil 50 through which current flows for this purpose.

The coil 50 and the magnetic device of the pilot valve 36 constitute a magnet.

It is usually sufficient to close the gas generator 30 by the pilot valve means 40, whereby the mass flow from the gas generator 30 to the airbag 22 can be adjustably controlled by simple opening and closing of the pilot valve means 40

However, this requires relatively large magnets, which require a relatively large installation space in the airbag module 16 and are also relatively sluggish.

In the embodiment described below, it is therefore proposed to insert a hydraulic drive 52 between the gas generator 30 and the pilot valve 36 for increasing the lifting action of the pilot valve device 40. As a result, the pilot valve 36 and thus the magnet arrangement can be designed to be significantly smaller, so that less installation space is required and switching can take place quickly.

The pilot valve 36 in fig. 3 is designed as a non-energized normally closed pilot valve 36, i.e. in the non-energized state the pilot valve means 40 is in its closed position. For this purpose, it is pressed by the pressure spring 54 in the direction of the closed position. In the closed position, the pilot valve means 40 closes an inlet opening 56 to the pilot valve 36, wherein this inlet opening 56 forms the connection of the pilot valve 36 to the hydraulic drive 52.

The hydraulic transmission 52 includes a control chamber 58 that is fluidly connected to the gas generator 30 via both a connecting bore 60 and an orifice 62. The connection hole 60 and the throttle hole 62 are holes provided separately from each other and converge at different positions into the control chamber 58 and the gas generator 30. Control chamber 58 is also fluidly connected to pilot valve 36 via input port 56. Control chamber 58 is also fluidly connected to airbag 22 through vent hole 64. A closing means 66 is arranged in the control chamber 58 for closing a valve seat 68, which in the first embodiment shown is arranged in the connecting bore 60. The closing means 66 is designed as a separating means 70 and divides the control chamber 58 into a first control chamber region 52 and a second control chamber region 74, wherein the two control chamber regions 72 and 74 are separated from one another. Separation device 70 fluidly separates two control chamber regions 72 and 74 from each other, but is still movable within control chamber 58.

Orifice 62 has an orifice plate 76 that fluidly connects gas generator 30 with first control chamber area 72. Pilot valve 36 is also fluidly connected to first control chamber region 72 via input port 56.

Connecting bore 60 fluidly connects gas generator 30 with second control chamber region 74.

In the present exemplary embodiment, closure element 66 is designed in the form of a sphere, both from the side of first control chamber region 72 and from the side of second control chamber region 74, with fluid pressure P of airbag gas 24 present in each respective control chamber region 72 and 74_FActing on the spherical closure device.

This is shown in the detail view of fig. 4. The first control chamber region 72 forms a first volume V here₁Wherein the balloon gas 24 acts on the upper surface of the closure device 66. As a result, a relatively large first pressure-acting surface a results from the side of the first control-chamber region 72 to the closing means 66₁。

The second control chamber region 74 is formed with a corresponding second pressure-acting surface a₂Second volume V of₂The second pressure application surface acts on the closing element 66 from below from the side of the second control chamber region 74. Furthermore, the region of the connection hole 60 closed by the closing means 66 forms a third volume V₃With a corresponding third pressure-acting surface a acting from below on the closure element 66₃。

Second pressure acting surface A₂And a third pressure acting surface A₃Add and react to the first pressure acting surface a₁。

In the first embodiment shown in fig. 3 and 4, the valve device 34 functions as follows:

the hydraulic actuator 52 has a spherical movable closure element 66 and is controlled by the pilot valve 36. As shown in fig. 3, the pilot valve 36 may be closed when not energized, but the pilot valve 36 may be provided as a normally open pilot valve 36 that is not energized as shown in fig. 5. The type of pilot valve 36 is selected depending on the safety scheme of the airbag system 18.

In the variant of fig. 3, which is normally closed without current supply, the pilot valve 36 closes the inlet opening 56 with the pilot valve device 40 by means of the compression spring 54 without the coil 50 being acted upon by current. A compression spring 54 is fastened in the region between the armature 48 and the pole piece 46. When current is applied to the coil 50, a magnetic field is generated between the armature 48 and the pole piece 46, thereby generating a magnetic force that counteracts the force of the compression spring 54. Pilot valve 36 switches at this point in time when the magnetic force between movable armature 48 and stationary pole piece 46 overcomes the force of pressure spring 54. The distance between the movable armature 48 and the stationary pole piece 46 decreases and the pilot valve device 40 releases the cross section of the inlet orifice 56. Thus, the airbag gas 24 may flow through the input aperture 56. The bag gas 24 is discharged to the bag 22 through the vent hole 78 of the pilot valve 36.

The hydraulic actuator 52 is designed as a central valve (Sitzventil). This means that the closing means 66 closes the valve seat 68. The diameter of the valve seat 68 is smaller than the diameter of the closure element 66, since the latter is designed as a sphere. Third pressure-acting surface a in the region of the connecting bore 60₃Constituted by the diameter of the valve seat 68. First pressure application surface a in first control chamber region 72₁Determined by the outer diameter of the closure device 66. First pressure application surface a in first control chamber region 72₁Is greater than the third pressure acting surface a on the valve seat 68₃. Thus, if the closure device 66 is applied with the same fluid pressure P from both sides_FDue to the larger first pressure acting surface A₁From the first control roomThe area 72 has a greater force to react to the force from the area of the valve seat 68. The closing means 66 thereby closes and bears against the valve seat 68.

Fluid pressure P in the connecting bore 60 after activation of the gas generator 30_FAnd (4) increasing. As a result, the fluid pressure P in the region of the valve seat 68_FActing on the closure device 66. The pilot valve 36 is closed in the variant of an unpowered normally closed valve. Due to the dynamic pressure, bladder gas 24 may flow into first control chamber area 72 through orifice plate 76. After a short time, the fluid pressure P in the first control chamber region 72_FWith the fluid pressure P in the region of the valve seat 68_FAnd (4) balancing. The closing means 66 continues to close the connection hole 60.

To dose the vent hole 64, and thus the amount of gas of the airbag gas 24, to the airbag 22, the pilot valve 36 is energized, whereby the pilot valve 36 releases the inlet hole 56. As a result, the fluid pressure P in the first control chamber region 52_FDescending, the closure means 66 switches and releases the cross section towards the drain opening 64 in the region of the valve seat 68. Mass flow from drain hole 64 and drain hole 78Are collected and input into airbag 22.

To enable mass flow of bag gas 24 to bag 22Stopping, the pilot valve 36 is closed again.

By actuating the pilot valve 36, a quantity of airbag gas 24 can be fed into the airbag 22 once or repeatedly.

Fig. 4 shows a detail of the volume V in a different region of the control chamber 58₁、V₂、V₃The pressure acting surface A is correspondingly shown₁、A₂And A₃Area ratio of (2). The third pressure acting surface A is arranged in the connecting hole 60 from the gas generator 30₃Acting on the closure device 66 within the seat diameter of the valve seat 68. In the second control chamber region 74, i.e. in the second volume V₂In (1) fromThe pressure applied to the vent hole 64 of the airbag 22 or the pressure from the airbag 22 acts on the second pressure acting surface a below the closing means 66₂The above. Second pressure acting surface A₂Between the outer diameter of the closure device 66 and the seating diameter of the valve seat 68. The pressure in this region is much lower than the pressure in the connection hole 60. The force acting on the closure means 66 acts on the closure means 66 in the same direction.

In the first control chamber region 72, the corresponding first pressure-acting surface a₁Acting on the outer diameter of the closure device 66. The direction of the force acting on the closure element 66 and the pressure-acting surface A₂And A₃The direction of the upward force is opposite. If a higher pressure is present in the first control chamber region 72, it acts on the first pressure-acting surface A₁Is greater than the force acting on the pressure-acting surface A₂And A₃The sum of the forces on. The closure device 66 closes and seals against a valve seat 68. If a lower pressure is present in the first control chamber region 72, it acts on the first pressure-acting surface A₁Is less than the force acting on the second pressure-acting surface A₂And a third pressure acting surface A₃The sum of the forces on. The closure device 66 opens and releases the attachment hole 60 thereby releasing the flow path to the airbag 22 through the vent hole 64.

The valve device 34 corresponding to the mode of operation of the valve device 34 from fig. 3 is shown in a longitudinal sectional view in fig. 5, with the only difference being that the pilot valve 36 from fig. 3 is designed as a non-energized normally closed pilot valve 36, whereas the pilot valve 36 from fig. 5 is designed as a non-energized normally open pilot valve 36. For this purpose, the components of the actuator region 44, in particular the pole shoe 46, the armature 48 and the compression spring 54, etc., are provided accordingly.

The pressure spring 54 in fig. 3 ensures that the pilot valve 36 is reliably closed. For this purpose, the opening pressure P of the pilot valve 36, which is determined by the prestress of the compression spring 54, is determined_OpenA high pressure P above the airbag gas 24 in the gas generator 30 that is expected when the gas generator 30 is activated_H。

In the pilot valve 36 of fig. 5, the pretension of the pressure spring 54 is designed to hold the pilot valve 36 in an open position, in which the pilot valve device 40 is in a defined open position.

Fig. 6, 7 and 8 show a second embodiment of the valve device 34, wherein the pilot valve 36 or the entire actuator region 44 is designed to correspond to the first embodiment in fig. 3 to 5. Only the hydraulic transmission 52 differs from the first embodiment in the second embodiment.

In a second embodiment, as can be seen in particular in fig. 7, the pressure application surface a₁、A₂And A₃Has been replaced compared to the first embodiment. In this case, the second pressure acting surface a is located in the connection bore 60 from the gas generator 30₂Acting between the outer diameter of the closure device 66 and the seating diameter of the valve seat 68. In the third volume V₃From the vent opening 64 to the airbag 22 or, in other words, from the pressure of the airbag 22, to the third pressure application surface a of the closure element 66₃The above. Second pressure acting surface A₂Between the outer diameter of the closure device 66 and the valve seat diameter of the valve seat 68. Fluid pressure P in this region_FMuch lower than the fluid pressure in the connecting bore 60. The force acting on the closure element 66 acts in the same direction on the closure element 66.

In the first control chamber region 72, the corresponding first pressure-acting surface a₁Acting on the outer diameter of the closure device 66. Acting on the first pressure-acting surface A₁Fluid pressure P on_FIn the direction of and acting on the two pressure-acting surfaces A₂And A₃The direction of the upward force is opposite. If there is a higher fluid pressure P in first control chamber area 72_FThen acting on the first pressure acting surface A₁Is greater than the forces acting on the two pressure surfaces A₂And A₃The sum of the forces on. The closure device 66 closes and seals against a valve seat 68. If there is a lower fluid pressure P in first control chamber area 72_FThen acting on the first pressure acting surface A₁Is less than the force acting on the two pressure-acting surfaces A₂And A₃The sum of the forces on. The closure device 66 opens and releases the flow path to the airbag 22.

In the second embodiment, the closure means 66 is located in the closed position on a valve seat 68 which is not located at the connection opening 60 but at the drain opening 64.

The valve device 34 in fig. 6 differs from the valve device 34 in fig. 8 only in that the valve device 34 in fig. 6 has a pilot valve 36 which is normally closed without power, whereas the valve device 34 in fig. 8 has a pilot valve 36 which is normally open without power.

The advantage of the above-described embodiment is that the entire valve device 34 can each be constructed very firmly and compactly, wherein the closure means 66 are of extremely simple design. By virtue of the design of the pilot valve 36 in a pre-controlled design, a large mass flow can be controlled by a relatively small pilot valve 36By switching the pilot valve 36 from an electrically non-conductive, normally open configuration to an electrically non-conductive, normally closed configuration, by using the preloaded pilot valve means 40 and the pressure measurement upstream of the mass flow-limiting orifice 76, different modified designs of the hydraulic drive 52 can be produced in a relatively simple manner depending on the safety concept of the airbag system 18.