JPH08268221A - Gas generator with collision sensor - Google Patents

Abstract

PURPOSE: To save a squib of a gas generator and to thin it by constituting the gas generator so as to bias energize an ignition pin by an energizing spring by oscillation by inertial force of a flapper and to fire ignition powder by flying by means of energizing force when the inertial force exceeds magnetic force of a magnet. CONSTITUTION: When a vehicle is decelerated, a flapper 31 is oscillated to the front of the vehicle by its inertial force. An ignition pin 27 retreats while pushing a compression spring 28 in accordance with the movement of the flapper 31 as it is held on the flapper 31 by a magnet 25. When deceleration becomes large and the ignition pin 27 further retreats, the ignition pin 27 strikes a stopper 29 and stops. When inertial force F of the flapper 31 becomes larger than a difference between magnetic force Fm of the magnet 25 and resiliency Fk of the compression spring 28, the ignition pin 27 is separated from the flapper 31 (magnet 25), flies out by the resiliency Fk of the compression spring 28, strikes ignition powder 30 and fires it. Consequently, inflammation powder is ignited, a gas generating agent burns and the gas for expansion of an air bag is generated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas generator with a collision sensor used in a vehicle occupant protection system.

[0002]

2. Description of the Related Art A conventional gas generator with a collision sensor uses a ball-in-tube type collision sensor as shown in FIG. That is, in FIG.
In this type of collision sensor, the ball 2 housed in the cylinder 65 is always in contact with one end of the rotatable driving shaft 3, and the other end of the driving shaft 3 has a bias spring 8 at its other end. It is biased by the bias pin 9 biased by. A rotating body 4 having an arcuate engagement surface is integrally provided on the driving shaft 3 in common with its rotation axis, and the rear end of the ignition pin 5 is provided at the end of the engagement surface. The engagement portion 5A is locked. The ignition pin 5 is provided with a striking portion 5B at the tip and is slidably accommodated in the passage 7, and is biased by a compression spring 10 in the direction of the ignition charge 6 arranged deep in the passage 7. When a collision occurs, the ball 2 moves in the direction of the arrow due to inertia, the driving shaft 3 rotates, and the engaging portion 5A of the ignition pin disengages from the engagement surface of the rotating body 4, and the ignition pin 5
Is released and flies toward the ignition powder 6 to ignite it.
On the basis of the ignition of the ignition powder 6, a gas generating agent in a gas generator (not shown) burns to generate gas.

[0003]

By the way, as shown in the figure, the above-mentioned collision sensor 1 includes the driving shaft 3
The ball 2, the ignition pin 5, the bias pin 9 in the direction perpendicular to
Since the bias spring 8 and the bias spring 8 are arranged in parallel, the thickness T
Is big. Therefore, when used in combination with a gas generator, for example, it cannot be attached to the bottom of an ordinary mass-produced gas generator, which requires a dedicated gas generator. was there. There is also a problem that the shape is complicated and the cost is high.

The present invention has been made in view of the above problems of the prior art. The object of the present invention is to use a flapper type collision sensor in combination with a mass-produced gas generator. It is to provide a gas generator with a collision sensor that is thin and can be manufactured at low cost.

[0005]

In order to solve the above-mentioned problems, a gas generator with a collision sensor according to the present invention is, in claim 1, a short cylindrical container having a cylindrical recess at the center of its bottom surface. A gas generator provided with an igniting agent arranged in the back of the recess, and a gas generating agent which is housed in the container and burns to generate a gas based on ignition of the igniting agent;
A plate-shaped flapper that is arranged along the bottom surface of the container and is swingable in the axial direction of the container with a part of its side as a fulcrum and that swings to the side opposite to the bottom surface due to inertia when deceleration occurs in the vehicle. And a magnet provided on the flapper for holding an ignition pin described later with a predetermined magnetic force, and most of the magnet is housed in a cylindrical recess of the gas generator so as to be able to move back and forth, and the ignition powder is ignited at the front end. A striking portion is formed for the ignition pin, the rear end of which is held by the magnet, and is interposed between the ignition pin and the container so as to be in the recess, and the repulsion force is generated by the retraction of the ignition pin. A collision sensor having an urging spring that accumulates and urges the ignition pin in the forward direction and a stopper that is provided in the container so as to be in the recess and that restricts the retracted position of the ignition pin. It is also.

According to a second aspect of the present invention, there is provided a sensor case, wherein a closed space is formed inside, a flat surface portion joined to the bottom surface of the container is formed on the upper surface, and a through hole is provided in the flat surface portion. A storage case is provided which is erected so as to surround the through hole of the flat surface portion, and has a cylindrical ignition part case which is fitted and inserted into the recess of the container of the gas generator, and the flapper and the magnet are provided in the sensor case. The ignition pin is housed in the ignition part case so as to be able to advance and retreat, and is capable of advancing and retracting through the through hole of the plane part, and the biasing spring is interposed between the ignition pin and the accommodation case. The stopper is provided in the storage case so as to be inside the ignition part case,
The storage case may be joined to the container via a seal.

Further, according to a third aspect of the present invention, the tip of the ignition part case is formed so as to abut a surface of an ignition charge disposed deep inside the recess of the container, and the impact part of the ignition pin is forwardly moved toward the center. And a ring-shaped sealing member having an inner diameter through which the protrusion of the ignition pin can pass near the tip of the ignition part case. Can be arranged.

Further, in the present invention, the sensor case of the storage case has a thickness that is smaller than that of the flat surface portion.
The flapper may be formed to be thin on the fulcrum side and thick on the anti-fulcrum side so as to correspond to the maximum swinging posture of the flapper housed inside.

[0009]

According to the structure of claim 1, when the ignition pin is biased by the biasing spring due to the swing of the flapper due to the inertial force, and the inertial force becomes equal to or larger than the magnetic force of the magnet, the ignition pin flies by the biasing force. Ignite. Therefore, the squib of the gas generator can be saved, and the driving shaft, cylinder, bias pin, etc., which are high in component cost, can be eliminated as compared with the conventional ball-in-tube type. Further, since the components such as the ignition pin arranged in the direction perpendicular to the flapper are substantially housed in the recess of the gas generator, the gas generator with a collision sensor is thin.

Further, according to the second aspect of the present invention, since the collision sensor portion is housed in the storage case and the storage case is joined to the gas generator, the entire storage case or an appropriate block is provided. By sub-assembling in advance, it is possible to easily assemble.

According to the third aspect of the present invention, the tip of the ignition part case is formed so as to contact the surface of the ignition charge, and the striking part of the ignition pin is provided with a slidable collar on the ignition part case. Since the sealing member is arranged near the tip of the ignition part case, the interior of the collision sensor can be sealed against the ignition of the ignition powder.

Further, according to the structure of the fourth aspect, the sensor case of the storage case is thin on the fulcrum side and on the anti-fulcrum side so that the thickness corresponds to the maximum swinging posture of the flapper housed inside. Since it is formed thick, waste of storage space can be eliminated.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. First, a first embodiment will be described with reference to FIGS. FIG. 1 is a cross-sectional view showing the structure of a gas generator with a collision sensor of the present invention, FIG. 2 is a schematic diagram showing the operation of the collision sensor, and FIG. 3 is a graph showing the variation in repulsive force of the compression spring and the separation force of the ignition pin. It is a graph which shows a relationship.

First, the structure will be described. In FIG. 1, the gas generator with a collision sensor includes a gas generator 11 and a collision sensor 12. Here, the gas generator 11 is attached to the central portion of the steering of the automobile, and in the attached state, the bottom surface side of the gas generator 11, that is, the lower side of the drawing is the front direction of the vehicle. The gas generator 11 has a flange 1 on the outer circumference.
3a is provided with a short cylindrical container 13,
The inside is divided into a central space 18 and an annular space by an inner wall 14, and a cylindrical recess 13b is provided in the center of the bottom surface of the central space 18. Then, a squib 15 is opened in the bottom of the recess, and gas holes 16 and 1 are formed in the inner wall 14 and the outer wall.
7 are each open. An igniting charge 30 is arranged in the inner part (bottom part) of the recess 13b, and a transfer charge (not shown) is arranged in the central space 18, and a gas generating agent and a gas filter (not shown) are arranged in the annular space. On the other hand, the collision sensor 12 includes a rectangular parallelepiped sensor case 20 having a space formed therein, an ignition part case 21 erected at the center of an upper surface 20a of the sensor case, and an attachment part formed around the sensor case 20. A storage case 24 composed of 23 and 23 is provided. The upper surface 20a of the sensor case 20 is joined to the bottom surface of the container 13 of the gas generator via the O-ring 32, and the ignition part case 21 is fitted and inserted in the recess 13b of the gas generator, and the tip is in the back of the recess 13b. It is in contact with the surface of the arranged ignition powder 30. The mounting portion 23 is formed into a shape that fits in the lower half of the container 13 of the gas generator together with the upper surface 20a of the sensor case, and is fastened to the flange 13a of the container 13 at the outer peripheral portion with bolts or the like.

In the sensor case 20, as shown in the figure, a flapper 31 made of a substantially rectangular plate material that extends along the upper surface 20a of the sensor case and also extends in the thickness direction of the paper is located at the center of one side. Part is supported by one end of a resin hinge 22, and the container 1 is supported by the resin hinge 22 as a fulcrum.
It is swingable in the axial direction of 3 (two-dot chain line). The inside of the sensor case 20 is filled with resin 38,
While holding the other end of the resin hinge 22, a predetermined skimmer 44 is formed between the resin hinge 22 and the tip of the flapper 31, so that the air passing through the skimmer 44 acts as an air damper when the flapper 31 swings. It has become. The magnet 25 is arranged near the center of the upper surface of the flapper 31. Sensor case upper surface 2 inside the ignition part case 21
A through hole 45 is provided at the center of 0a, and a cylindrical stopper 29 of a predetermined length is provided upright around the through hole 45, and the inner peripheral portion of the stopper 29 and the through hole 45 are slidably ignited. The pin 27 is stored. A rear end of the ignition pin 27 is held by the magnet 25 with a predetermined magnetic force, and a conical projection at the center and a circular flange around the projection are provided at the front end, which form a striking portion 27a. There is. The flange of the striking portion 27a is slidable on the inner circumference of the ignition portion storage case 21. When the ignition pin 27 retreats to a certain position, the brim comes into contact with the tip of the stopper 29. At this position, the ignition pin 27 is indicated by a two-dot chain line as the flapper 31 swings. The flapper 31 is set to a position before it retracts to a position corresponding to the maximum swing position, and the length of the stopper 29 is set to such a position that the contact position with the ignition pin becomes such a predetermined position. There is. In addition, the compression spring 2 is provided between the rear surface of the collar and the upper surface of the sensor case.
8 is interposed. An O-ring 39 having an inner diameter larger than the outer diameter of the conical projection of the striking portion 27a is arranged near the tip of the ignition portion case 21.

In this way, the ignition part of the collision sensor 12 is
It is housed in the squib housing of a normal gas generator, and the flapper 31 is only arranged along the bottom surface of the gas generator 11, so that the gas generator has a thin collision sensor. In addition, the squib of the gas generator 11 (which accounts for about 33% of the total cost of all parts of the gas generator) is saved, and the driving shaft, which has higher parts cost than the conventional ball-in-tube system, Cylinder, bias pin, etc. are unnecessary. Further, since the entire collision sensor 12 is housed in the housing case 24, it can be easily assembled by sub-processing in advance.

Next, the operation will be described with reference to FIGS. In FIG. 2A, when deceleration occurs in the vehicle, the flapper 31 causes the inertial force F to cause the flapper 31 to move forward (downward in the drawing) of the vehicle.
Rock to. The ignition pin 27 is a magnet 25 and a flapper 31.
Therefore, the flapper 31 moves and the compression spring 28 is pushed back as the flapper 31 moves. Therefore, the compression spring 2
Reference numeral 8 also serves as a bias spring for the flapper 31.
In FIG. 2B, when the ignition pin 27 further retracts, the ignition pin 27 hits the stopper 29 and stops. Then, in FIG. 2C, when the inertial force F of the flapper 31 becomes larger than the difference between the magnetic force Fm of the magnet 25 and the repulsive force Fk of the compression spring 29 (that is, the separation force), the flapper 3
The ignition pin 27 is separated from the magnet 1 (magnet 25), and is ejected by the repulsive force Fk of the compression spring 28 and hits the ignition charge 30 to ignite it. The transfer charge is ignited by the ignition of the ignition charge 30, and the gas generating agent is burned by the ignition of the transfer charge to generate gas, and the generated gas is cooled and purified by the filter and released from the gas generator. In FIG. 1, when the ignition powder 30 is ignited as described above, the presence of the O-rings 32 and 39 prevents hot air from leaking outside and into the collision sensor 12.

Next, the effect of the collision sensor of the present invention on the sensitivity will be described with reference to FIG. The factors that determine the sensitivity of the collision sensor are the magnetic force Fm of the magnet, the travel distance of the ignition pin, the repulsive force Fk of the compression spring, and the air damper action. Of these, the repulsive force Fk of the compression spring that is particularly likely to vary is absorbed by the separation force between the flapper and the ignition pin. That is, as shown in FIG. 3, the magnetic force Fm of the magnet is set to a predetermined value that is larger than the repulsive force Fk of the compression spring when the ignition pin is at the stopper position. At this time, the difference between the magnetic force Fm of the magnet and the repulsive force Fk of the compression spring becomes the ignition pin separating force 70, which is small for a strong spring and large for a weak spring. , Absorb the variation.

Next, a second embodiment of the present invention will be described with reference to FIG. 4, which is a sectional view. 4 is different from FIG. 1 in that the thickness of the sensor case 40 is thin on the fulcrum side and thick on the anti-fulcrum side so as to correspond to the maximum swinging posture (two-dot chain line) of the flapper 31 housed inside. It is the point that is formed. With such a configuration, it is possible to eliminate waste of the storage space of the sensor case 40. Therefore, in the gas generator housing portion of the steering wheel, which has many restrictions in the thickness direction, even if the fixing portion 41 of the steering wheel to the steering shaft is protruding to, as shown in FIG. You can

Next, a third embodiment of the present invention will be described with reference to FIG. 5, which is a sectional view. 5, the main difference from FIG. 1 is that the gas generator 50 with a collision sensor is equipped with a squib 5
This is a combination of a gas generator 51 including two and a collision sensor 60 configured to close electrical contacts by swinging a flapper 61. That is, the collision sensor 60
As shown in the drawing, a movable piece 53 made of an elastic wire formed in an inverted V shape is cantilevered at one end, and one end of the inverted V shape is in contact with the flapper 61 on the side wall of the case. . On the other hand, a plate-shaped contact piece 54 is arranged along the bottom surface of the case 60, and when the flapper 61 swings, the tip of the movable segment 53 can contact. Both terminals A and B of the movable piece 53 and the contact piece 54 are connected to both terminals C and D of the squib 52 via a power source (not shown). Even with such a configuration, it is possible to obtain a thin gas generator with a collision sensor.

[0021]

As described above, in the gas generator with the collision sensor according to the present invention, the parts arranged in the direction perpendicular to the flapper such as the ignition pin are substantially housed in the recess of the gas generator, and the ignition pin is The flapper is biased by the biasing spring due to the swinging force by the inertial force, and when the inertial force is equal to or greater than the magnetic force of the magnet, the biasing force causes the ignition powder to ignite. And the squib of the gas generator can be saved. Further, as compared with the one using the ball-in-tube method, it is possible to eliminate the driving shaft, cylinder, bias pin, etc., which have high component costs. Therefore, a low-cost gas generator with a collision sensor can be provided.

Further, when the collision sensor is stored in the storage case, the entire storage case or appropriate blocks can be sub-assembled in advance to facilitate the assembly.

If a sealing member is arranged near the tip of the ignition part case, the interior of the collision sensor can be sealed against the ignition of the ignition charge.

Further, assuming that the sensor case of the storage case is formed such that its thickness is thin on the fulcrum side and thick on the anti-fulcrum side so as to correspond to the maximum swinging posture of the flapper housed inside. It is possible to eliminate waste of the storage space, which is an advantageous effect particularly in the gas generator storage portion of the steering wheel, which has many restrictions in the thickness direction.

[Brief description of drawings]

FIG. 1 is a sectional view showing a structure of a gas generator with a collision sensor according to a first embodiment of the present invention.

2 is a schematic diagram showing the operation of the collision sensor. FIG.

FIG. 3 is a graph showing the relationship between the variation in repulsive force of the compression spring and the separating force of the ignition pin.

FIG. 4 is a sectional view showing a structure of a gas generator with a collision sensor according to a second embodiment of the present invention.

FIG. 5 is a sectional view showing a structure of a gas generator with a collision sensor according to a third embodiment of the present invention.

FIG. 6 is a sectional view showing the structure of a conventional collision sensor.

[Explanation of symbols]

 11, 51 Gas generator 12, 60 Collision sensor 13 Container 20 Sensor case 21 Ignition part case 24 Storage case 25 Magnet 27 Ignition pin 27a Impact part 28 Compression spring (biasing spring) 29 Stopper 30 Ignition agent (ignition means) 31, 61 flapper 32 O-ring (seal) 39 O-ring (sealing member) 52 squib (ignition means)

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[Procedure amendment]

[Submission date] June 20, 1995

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Claims (4)

[Claims] 1. A short cylindrical container (13) having a cylindrical recess at the center of the bottom surface, an ignition powder (30) arranged deep inside the recess, and the ignition powder stored in the container. A gas generator (11) equipped with a gas generating agent that burns to generate gas when ignited, and is arranged along the bottom surface of the container and has a part of its side as a fulcrum in the axial direction of the container. The plate-shaped flapper (31) is swingable and swings to the side opposite to the bottom surface due to inertia when deceleration occurs in the vehicle, and a magnet (25) provided on the flapper and holding an ignition pin described later with a predetermined magnetic force. ), And most of it is housed in the cylindrical recess of the gas generator so as to be able to move back and forth, a striking part for igniting the ignition powder is formed at the front end, and the rear end is held by the magnet. Ignition pin (27)
And an urging spring (2) which is interposed between the ignition pin and the container so as to be in the recess, accumulates a repulsive force by retracting the ignition pin, and urges the ignition pin in the forward direction.
8) and provided in the container so as to be in the recess,
A gas generator with a collision sensor, comprising a collision sensor (12) having a stopper (29) for regulating the retracted position of the ignition pin. 2. A sensor case (20) in which a closed space is formed inside, a flat surface portion joined to the bottom surface of the container is formed on the upper surface, and a through hole is provided in the flat surface portion, and the flat surface portion. The flapper (31) and the magnet are provided with a storage case (24) standing upright to surround the through hole and having a cylindrical ignition part case (21) fitted and inserted into a recess of the container of the gas generator. (25) is housed in the sensor case (20), and the ignition pin (27)
Is retractably housed in the ignition part case (21) and is retractable in the through hole of the plane part, and the biasing spring (28) is interposed between the ignition pin and the storage case (24). The stopper (29) is provided on the storage case (24) so as to be inside the ignition case, and the storage case (24) is joined to the container via a seal (32). Gas generator with a collision sensor as described. 3. A tip (27a) of the ignition pin is formed so that a tip of the ignition case (21) is in contact with a surface of an ignition charge (30) disposed deep inside the recess of the container.
Is provided with a forward convex portion in the center and a slidable brim around the convex portion around the convex portion, and an inner diameter through which the convex portion of the ignition pin can pass near the tip of the ignition portion case. The gas generator with a collision sensor according to claim 2, wherein an annular sealing member (39) having is arranged. 4. A sensor case (40) for the storage case.
2. The thickness of the flat portion is thin on the fulcrum side and thick on the anti-fulcrum side so as to correspond to the maximum swinging posture of the flapper (31) housed inside the flat portion. A gas generator with a collision sensor according to.