JPH0649233U - Airbag starter - Google Patents

Abstract

(57) [Abstract] [Purpose] Without adversely increasing manufacturing tolerances, the adverse effect of frictional force can be significantly reduced and the ignition pin can be locked with the trigger member with high accuracy, which ensures a reliable and stable start. To obtain a activating device for an air bag. [Structure] In the starting device 34, a roller 70 is attached to the tip of a trigger shaft 56 for locking the ignition pin 66, and the roller 70 is in rolling contact with the ignition pin 66 and locked. The center of rotation of the trigger shaft 56 is the ignition pin 6
It is provided so as to be offset greatly downward with respect to the locking position of 6. Therefore, the frictional force between the trigger shaft 56 and the ignition pin 66 is greatly reduced, the rotation arm length L ₃ and the hanging margin G ₃ can be secured large, and it is not necessary to unnecessarily increase the manufacturing tolerance. As a result, the operation of the trigger shaft 56 (the unlocking operation of the ignition pin 66) can be smoothly performed, and reliable and stable startability can be obtained.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an airbag starting device for inflating a bag which is attached to a vehicle.

[0002]

[Prior art]

 In an airbag, for example, an airbag attached to a steering wheel, an activating device is provided, and the activating device causes the bag to be inflated so as to be interposed between the steering wheel and an occupant when the vehicle is suddenly decelerated.

As shown in FIG. 5, in a conventional starting device 80 of this type, a spherical ball 86 is housed in a cylinder 84, and one end of a drive shaft 88 is in contact therewith. A trigger shaft 90 serving as a trigger member is fixed to the middle portion of the drive shaft 88.

The trigger shaft 90 can be engaged with the ignition pin 92, and is supported by the body of the starter 80 so as to be rotatable about its axis, whereby the drive shaft 88 is triggered. At the same time, the trigger shaft 90 can be rotated around its axis.

On the other hand, the other end of the drive shaft 88 is pressed by a via spin 83 having a bias spring 82. Therefore, the drive shaft 88 normally holds the ball 86 in a predetermined position in the cylinder 84, and the trigger shaft 90 engages with the ignition pin 92 to resist the biasing force of the firing spring 91. The pin 92 is in a locked state.

At the time of sudden deceleration of the vehicle, the ball 86 housed at a predetermined position in the cylinder 84 moves in the arrow A direction, which is the forward direction of the vehicle, by the inertial force against the biasing force of the bias spring 82. The drive shaft 88 is rotated, the trigger shaft 90 fixed to the drive shaft 88 rotates counterclockwise, and the locking of the ignition pin 92 by the trigger shaft 90 is released, whereby the ignition pin 92 is released. A bag (not shown) collides with the detonator 94 and is ignited so that a bag (not shown) is inflated (for example, JP-B-60-248454, JP-A-60-248455, and JP-A-60-248456). , JP-A-60-248457, etc.).

[0007]

[Problems to be solved by the device]

By the way, in such a conventional starting device 80, compared to L ₁ (distance between the rotation center of the drive shaft 88 and the pressing position by the ball 86), L ₂ (rotation center of the trigger shaft 90 and the ignition pin 92). The distance to the locking position) is relatively small, so that the influence of the frictional force (resistance) between the trigger shaft 90 and the ignition pin 92 is reduced.

However, if L ₂ is made smaller than L ₁ in this way, the engagement margin G _{1 of} the trigger shaft 90 with respect to the ignition pin 92 is inevitably small, and therefore the operation of the trigger shaft 90 (the ignition pin 92 It was necessary to make strict manufacturing tolerances so that the operation performance would not become unstable by ensuring the disengagement operation of. Therefore, the cost was high.

On the other hand, in order to implement such manufacturing tolerances without making it strict, conversely, L ₂ may be increased, but as described above, the hanging allowance G ₁ also increases and the frictional force increases. The operation of the trigger shaft 90 (disengagement operation of the ignition pin 92) cannot be performed smoothly. Further, L ₁ is inevitably increased, and the overall size of the activation device 80 is also increased.

As described above, in order to reduce the frictional resistance and smoothly operate the trigger shaft 90 to stabilize the operation performance, it is necessary to make the manufacturing tolerances strict, resulting in a high cost, and the manufacturing tolerances. In order to reduce the cost without stricting, the frictional resistance increases and the operation of the trigger shaft 90 becomes unstable, which is a trade-off against each other.

In consideration of the above facts, the present invention can significantly reduce the adverse effect of frictional force and increase the accuracy of the ignition pin locking state by the trigger member without unnecessarily increasing manufacturing tolerances. It is also an object of the present invention to provide an airbag starter having a stable startability.

[0012]

[Means for Solving the Problems]

 The airbag start-up device according to the present invention detects a sudden deceleration of a vehicle by inertial movement, a mass body that engages with the mass body and holds the mass body at a predetermined position, and the inertia of the mass body when the vehicle suddenly decelerates. The drive shaft rotated by the movement, the ignition pin that acts on the detonator to expand the bag and is always urged in the direction to collide with the detonator, and the ignition pin that engages with the ignition pin to prevent the ignition pin from moving. When the vehicle suddenly decelerates, the trigger member rotates together with the drive shaft to release the movement prevention of the ignition pin, and the drive shaft moves in the opposite direction to the direction in which the trigger member releases the movement prevention of the ignition pin during the vehicle sudden deceleration. In an airbag starting device including a pressing member that presses, a roller is disposed at a portion of the trigger member that engages with the ignition pin, and the roller is in rolling contact with the ignition pin. It is, and is characterized in that the center of rotation of the trigger member disposed displaced from the moving locus of the ignition pin.

[0013]

[Action]

 In the airbag starting device having the above-described structure, since the roller is disposed at the engagement portion of the trigger member with the ignition pin, the ignition pin is locked by rolling contact with the roller.

Therefore, the frictional force (resistance) between the trigger member and the ignition pin is greatly reduced. Therefore, even if the rotation arm length up to the ignition pin locking position of the trigger member (the length between the rotation center of the trigger member and the locking position of the ignition pin) is increased, in other words Even if the hanging allowance is increased, it is less likely to be affected by frictional force (resistance). Therefore, it is not necessary to unnecessarily increase the manufacturing tolerance, and the cost is reduced.

Further, since the rotation center of the trigger member is provided by being displaced (offset) from the movement locus of the ignition pin, when the rotation center of the trigger member is simply located on the movement locus of the ignition pin (in other words, In that case, the thickness dimension (size) of the starter device is smaller than that in the case where the virtual line connecting the rotation center of the trigger member and the locking position of the ignition pin is provided substantially orthogonal to the drive shaft. The length of the rotating arm is further increased without increasing the length of the rotary arm, and a large margin for engagement with the ignition pin can be secured.

Thus, without unnecessarily increasing manufacturing tolerances, the adverse effect of frictional force can be greatly reduced, and the ignition pin can be locked with the trigger member with high accuracy, which allows the trigger member to operate (ignite). The operation of releasing the engagement of the pin) can be performed smoothly, and reliable and stable startability can be obtained. Also, the overall size of the activation device does not increase.

[0017]

【Example】

 FIG. 4 shows an airbag 10 to which an airbag starting device according to an embodiment of the present invention is applied. The arrow FR direction in the figure indicates the front side of the vehicle.

In the airbag 10, the base plate 12 is supported by a support means (not shown) substantially in parallel with the hub 14A of the steering wheel 14 (both shown by imaginary lines). A bag 16, a cover 18, and an inflator 20 are attached to the base plate 12.

The bag 16 is arranged in a folded state on the occupant side (upper side in FIG. 4) of the base plate 12. The edge of the bag 16 on the opening side is attached to a substantially central portion of the base plate 12 via a ring plate 22. The ring plate 22 is fastened to the base plate 12 with a bolt (not shown), and the edge of the bag 16 on the opening side is pressed against the base plate 12.

The cover 18 is arranged on the occupant side of the base plate 12 and stores the bag 16 between the cover 18 and the base plate 12. A frame-shaped core metal (not shown) is embedded in the periphery of the cover 18, and is attached to the base plate 12 by a rivet or the like via the core metal. A thin portion 24 is formed at a portion of the cover 18 facing the base plate 12, and is easily broken at this portion.

The inflator 20 has a cylindrical shape, and is arranged in a state of being inserted into the bag 16 while penetrating substantially the central portion of the base plate 12. A flange 20A is formed on the outer periphery of the inflator 20, and is fixed to the surface of the base plate 12 on the side opposite to the occupant (lower side in FIG. 4) with a bolt (not shown).

As shown in FIG. 3, the gas generating substance 30 is enclosed in the inflator 20. The gas generating substance 30 is decomposed by combustion to release a large amount of gas, and the gas can inflate the bag 16. The gas generating substance 30 may be, for example, one containing sodium azide. A detonator and an explosive charge (not shown) are provided around the gas generating substance 30 so that the gas generating substance 30 is burned when the detonator ignites.

Further, the inflator 20 has a built-in starter 34 for igniting a detonator (not shown) to burn the gas generating substance 30.

As shown in FIG. 1, two cylinders 40 supported by a block 38 are provided side by side in a cylindrical case 36 of the starting device 34 (only one cylinder 40 is shown in the drawing. Shown).

The cylinder 40 is arranged with a O-ring 44 interposed in a cylinder fitting hole 42 formed through the case 36 and the block 38. A spherical ball 48 as a mass body is accommodated in the cylinder 40 so as to be movable in the direction of arrow A in FIG. The ball 48 moves in the direction of arrow A in FIG. 1 due to inertial force when the vehicle suddenly decelerates.

An upper end portion of the drive shaft 54 is arranged in contact with the ball 48 in the vehicle front direction of the ball 48. A trigger shaft 56 as a trigger member is integrally fixed to the drive shaft 54 at a substantially intermediate portion in the axial direction of the drive shaft 54.

As shown in detail in FIG. 2, the lower end of the trigger shaft 56 is fixed to the drive shaft 54 and extends upward. The drive shaft 54 and the trigger shaft 56 are V-shaped as a whole. It is configured. A support pin 57 is formed so as to project from the fixing portion of the trigger shaft 56. The support pin 57 is fitted into a support hole (not shown) formed in the case 36, so that the trigger shaft 56 and the drive shaft 56 are driven. 54 is rotatably supported.

On the other hand, a roller 70 is rotatably attached to the upper end of the trigger shaft 56 by a shaft 59. The roller 70 is for locking an ignition pin 66, which will be described later.

A bias pin 60 that constitutes a pressing member is in contact with the lower end of the drive shaft 54, and a compression coil spring 58 is arranged between the bias pin 60 and the block 38. . Therefore, the lower end of the drive shaft 54 is always urged toward the front side of the vehicle via the bias pin 60 (the state shown in FIG. 2), whereby the ball 48 normally moves toward the drive shaft 54. The upper end portion is biased toward the vehicle rear side and is housed in a predetermined position inside the cylinder 40.

An ignition pin 66 is locked to the roller 70 attached to the upper end of the trigger shaft 56.

The ignition pin 66 is composed of a pin portion 66A and a locking portion 66B formed at an axially intermediate portion of the pin portion 66A. The tip of the pin portion 66A (the end portion on the vehicle rear side in FIG. 1) is formed in a needle-like shape. On the other hand, the locking portion 66B is formed in a disk shape in which a large-diameter portion and a small-diameter portion located on the vehicle rear side of the large-diameter portion are continuous, and a boundary portion between the large-diameter portion and the small-diameter portion is further formed. It is formed with an inclination. This inclined surface corresponds to the roller 70 of the trigger shaft 56, and the ignition pin 66 has a structure in which the locking portion 66B (the inclined surface) is in rolling contact with the roller 70 of the trigger shaft 56 and locked. is there.

Further, in this case, as described above, in the trigger shaft 56, the center of rotation thereof, that is, the support pin 57 is located largely below the roller 70 (the locking position of the ignition pin 66). Since the center of rotation of the trigger shaft 56 is displaced (offset) from the locus of movement of the ignition pin 57, the rotation arm length L ₃ (trigger shaft 56) up to the ignition pin 57 locking position of the trigger shaft 56 is increased. The length between the rotation center of 56 and the locking position of the ignition pin 57 by the roller 70) is provided sufficiently long without increasing the thickness dimension of the starter 34.

On the other hand, one end of the compression coil spring 64 abuts on the vehicle front side of the locking portion 66B (large-diameter portion) of the ignition pin 57. The compression coil spring 64 is housed in a bottomed hole 76 formed in the block 74, so that the ignition pin 66 is always biased toward the rear side of the vehicle. When the trigger shaft 56 rotates around the support pin 57 together with the drive shaft 54 to release the engagement between the locking portion 66B of the ignition pin 66 and the roller 70 of the trigger shaft 56, the compression coil spring 64 is released. By the urging force of the ignition pin 66, the ignition pin 66 moves to the rear side of the vehicle in FIG. 1 and collides with the detonator 68.

The detonator 68 can be exploded by collision with the ignition pin 66 and ignite an explosive charge (not shown).

Next, the operation of this embodiment will be described. In a normal state of the vehicle, the lower end of the drive shaft 54 is biased toward the vehicle front side via the bias pin 60, so that the ball 48 is moved toward the vehicle rear side by the upper end of the drive shaft 54. It is energized and stored in a predetermined position inside the cylinder 40.

The ignition pin 66 urged to the vehicle rear side by the compression coil spring 64 has a locking portion 66 B (an inclined surface between the large diameter portion and the small diameter portion) on the roller 70 of the trigger shaft 56. It is locked by rolling contact.

When the vehicle suddenly decelerates, the ball 48 housed at a predetermined position in the cylinder 40 inertially moves in the direction of arrow A in FIG. 1 to press the drive shaft 54.

Therefore, the trigger shaft 56 rotates around the support pin 57 together with the drive shaft 54, and the engagement between the roller 70 of the trigger shaft 56 and the locking portion 66B of the ignition pin 66 is released. Therefore, the urging force of the compression coil spring 64 moves the ignition pin 66 in the direction opposite to the arrow A in FIG. 1, and the pin portion 66A collides with the detonator 68. The detonator 68 is ignited by the collision with the ignition pin 66 (pin portion 66A) and explosive charge not shown explodes, whereby the gas generating substance 30 is burned and the bag 16 expands.

Here, in the starting device 34, since the ignition pin 66 is locked by rolling contact with the roller 70 of the trigger shaft 56, the frictional force (resistance) between the trigger shaft 56 and the ignition pin 66 is reduced. Significantly reduced. Therefore, even if the rotation arm length L _{3 of} the trigger shaft 56 up to the ignition pin 66 locking position (the length between the rotation center of the trigger shaft 56 and the ignition pin 66 locking position) is increased, even by increasing the consuming allowance G ₃ between ignition pin 6 6 if, hardly influenced by the frictional force (resistance). Therefore, it is not necessary to unnecessarily increase the manufacturing tolerance, and the cost is reduced.

Further, in the starting device 34, the center of rotation of the trigger shaft 56 is displaced (offset) from the movement locus of the ignition pin 66 as shown in FIG. Is located on the movement locus of the ignition pin 66 (in other words, a virtual line connecting the rotation center of the trigger shaft 56 and the locking position of the ignition pin 66 is provided substantially orthogonal to the drive shaft 54). The rotation arm length L ₃ is further increased without increasing the thickness dimension (size) of the starter 34, and a large margin G ₃ with the ignition pin 66 is secured. be able to.

Thus, without unnecessarily increasing the manufacturing tolerance, the adverse effect of frictional force can be significantly reduced and the ignition pin 66 can be locked with the trigger shaft 56 with high accuracy, which allows the trigger shaft 56 to be locked. Can be smoothly performed (disengagement operation of the ignition pin 66), and reliable and stable startability can be obtained. Also, the overall size of the activation device 34 does not increase.

[0042]

[Effect of device]

 As described above, the airbag starter according to the present invention can significantly reduce the adverse effect of frictional force and increase the accuracy of locking the ignition pin by the trigger member without unnecessarily increasing manufacturing tolerances. This has the excellent effect of ensuring a reliable and stable startability.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view showing a schematic structure of a starting device according to an embodiment of the present invention.

FIG. 2 is an enlarged view of an essential part of FIG. 1 showing a locked state of an ignition pin and a roller.

FIG. 3 is a partial cross-sectional view of the inflator showing a mounting state of the starting device.

FIG. 4 is a cross-sectional view showing a schematic structure of an airbag to which a starting device is applied.

FIG. 5 is a vertical cross-sectional view showing a conventional example of a starting device.

[Explanation of symbols]

 10 Airbag 34 Starter device 48 Ball (mass body) 54 Drive shaft 56 Trigger shaft (trigger member) 58 Compression coil spring 60 Bias pin (pressing member) 64 Compression coil spring 66 Ignition pin 66A Pin portion 66B Locking portion 70 Roller

Claims (1)

[Scope of utility model registration request] 1. A mass body for detecting sudden vehicle deceleration by inertial movement, and a drive shaft which engages with the mass body and holds the mass body at a predetermined position and which is rotated by the inertial movement of the mass body when the vehicle suddenly decelerates. When the ignition pin is actuated on the detonator to expand the bag and is always urged in the direction to collide with the detonator, the ignition pin engages with the ignition pin to prevent the ignition pin from moving, and when the vehicle suddenly decelerates, it rotates together with the drive shaft. An air provided with a trigger member that moves to release the movement inhibition of the ignition pin, and a pressing member that presses the drive shaft in a direction opposite to the direction in which the trigger member releases the movement inhibition of the ignition pin when the vehicle rapidly decelerates. In the bag starting device, a roller is disposed at an engagement portion of the trigger member with the ignition pin to make rolling contact with the ignition pin, and the trigger member. Air bag activation device, wherein a rotation center provided displaced from the moving locus of the ignition pin.