JPH0643573U - Acceleration sensor - Google Patents

Abstract

(57) [Summary] [Purpose] Simple structure without sacrificing operability.
(EN) An acceleration sensor that can be easily reset even after performing an operation test for confirming sensitivity and the like. The ignition pin 24 is held by a trigger pawl 38, and the inertial mass body 32 abuts on the trigger pawl 38 to maintain it. Inertia mass 3 due to inertial force
When 2 moves, the trigger pawl 38 rotates and the holding of the ignition pin 24 is released. When the ignition pin 24 is moved, the trigger pawl 38 is pressed by the inertial mass body 32 in the direction in which the trigger pawl 38 is engaged with the ignition pin 24. Therefore, by simply pushing the ignition pin 24 from the outside, when the ignition pin 24 reaches the initial position, the trigger pawl 38 is rotated to engage and hold the flange portion 28 and return to the initial state.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an acceleration sensor for detecting a sudden deceleration state of a vehicle.

[0002]

[Prior art]

 For example, in a seat belt device installed in a vehicle, the webbing mounted on the occupant is pulled back by a predetermined amount when the vehicle suddenly decelerates to forcibly remove the slack of the webbing for the occupant and tighten the webbing to improve occupant restraint. Some are equipped with a so-called pretensioner.

In this type of pretensioner, there are a pretensioner that forcibly rotates the winding shaft of the webbing retractor to tension the webbing and a pretensioner that tensions the webbing by forcibly pulling the buckle. However, for example, in a structure in which the webbing is tensioned by pulling a buckle, a gas generator equipped with an acceleration sensor is provided. A cylinder is arranged in this gas generator and is connected to a buckle via a wire or the like.

When the vehicle suddenly decelerates, this is detected by the acceleration sensor, the gas generator operates, gas is instantaneously generated, the cylinder is moved, and this moving force is transmitted to the buckle via the wire. The buckle is forcibly moved and the webbing is strained.

[0005]

[Problems to be solved by the device]

 By the way, the acceleration sensor used in such a conventional pretensioner basically consists of an ignition pin that ignites a detonator, an inertial body that inertially moves due to large acceleration, and an interposition between the ignition pin and the inertial body. Although it is composed of a trigger member such as a ball that blocks the movement of the ignition pin (as an example, Japanese Patent Publication No. 52-13104), the trigger member is usually interposed between the inertial body and the ignition pin. In this condition, the movement of the ignition pin was blocked.Therefore, once the trigger member is disengaged from between the inertial body and the ignition pin to release the movement prevention state of the ignition pin, the movement of the ignition pin is restarted. It was extremely difficult to reset to the blocking state.

Therefore, for example, in the case of confirming the sensitivity of the operation of the acceleration sensor or the like and conducting an operation inspection as to whether or not the operation is reliable, even if the operation inspection itself can be performed, the gas generator is officially installed after that. It cannot be assembled to enable operation (reset), and the operation test of the acceleration sensor cannot be omitted.

In consideration of the above facts, the present invention provides an acceleration sensor which has a simple structure and can be easily reset even after performing an operation test for confirming sensitivity without sacrificing operability. That is the purpose.

[0008]

[Means for Solving the Problems]

 The acceleration sensor according to the present invention is arranged so as to be movable along the axial direction, and has an ignition pin that moves in the axial direction by an urging force of a firing spring to ignite a detonator and a direction in which a support shaft contacts and separates from the ignition pin. In the state of being rotatably supported by the ignition pin and rotated in the direction of approaching the ignition pin, the ignition pin urged by the firing spring remains pressed in the direction of separating from the ignition pin. A trigger pawl that holds the ignition pin at a position separated from the detonator against the urging force of the firing spring, and allows the ignition pin to move when rotated in a direction away from the ignition pin. , The trigger pawl is arranged so as to be able to enter and leave the rotation path of the trigger pawl, and the trigger pawl is always operated by the trigger spring. When the trigger pawl is energized in the direction of entering the rotation path of the trigger pawl and enters the rotation path of the trigger pawl, it engages with the trigger pawl to prevent the trigger pawl from rotating around the support shaft to maintain the ignition pin holding state. When the predetermined load is applied, the trigger pawl is disengaged from the trajectory of the trigger pawl by the inertial force so that the trigger pawl is unblocked so that the trigger pawl can be pivoted about the support shaft and the triggering force of the trigger ring is applied. An inertial mass body that presses the trigger pawl in a direction approaching the ignition pin.

[0009]

[Action]

 In the acceleration sensor with the above configuration, normally, the ignition pin is located at a position away from the detonator against the biasing force of the firing spring, and the trigger pawl holds the ignition pin while rotating in a direction approaching the ignition pin. The inertial mass enters the rotation path of the trigger pawl by the trigger spring and blocks the rotation of the trigger pawl to maintain the ignition pin holding state.

Here, when a large acceleration is applied to the acceleration sensor, the inertial mass body inertially moves and is separated from the rotation path of the trigger pawl, and the trigger pawl can be rotated around the spindle. For this reason, the trigger pawl pressed by the ignition pin urged by the firing spring in the direction away from the ignition pin rotates in the direction away from the ignition pin to release the holding of the ignition pin, and the ignition pin is released. The urging force of the firing ring moves in the axial direction to ignite the detonator.

Once the ignition pin has moved, the trigger pawl is pressed by the inertial mass body urged by the trigger spring in a direction approaching the ignition pin.

Further, when the acceleration sensor that has been operated once is made to be operable again (reset), the ignition pin is moved in the axial direction against the biasing force of the firing spring.

Since the trigger pawl is pressed by the inertial mass body urged by the trigger spring in a direction approaching the ignition pin, the trigger pawl is attached to the ignition pin when the ignition pin reaches the initial position. Rotate in the direction of approaching and engage the ignition pin, and hold the ignition pin in the initial position separated from the detonator.

As described above, by simply moving the ignition pin to the initial position along the axis, the trigger pawl can be rotated to return to the initial state in which the ignition pin is held. Therefore, for example, it is possible to easily carry out the operation inspection of the acceleration sensor and then properly mount the gas generator to the operable state (reset).

[0015]

【Example】

 FIG. 1 is a sectional view of an acceleration sensor 10 according to the present invention.

The acceleration sensor 10 includes a sensor cover 12. The sensor cover 12 is formed in a cylindrical shape having a bottom wall 14 at one end, and the bottom wall 14 is formed with a through hole 16 on the axis. A guide 18 is coaxially arranged inside the sensor cover 12. The guide 18 is also formed in a substantially cylindrical shape, one end of which is connected and fixed to the bottom wall 14 of the sensor cover 12, and the other end of which is closed by a plate 20 and integrally connected and fixed to the sensor cover 12. There is. Further, a through hole 22 is formed in an axially intermediate portion of a side wall of the guide 18 and corresponds to a trigger pawl 38 described later.

An ignition pin 24 is arranged inside the guide 18. The ignition pin 24 is formed in a substantially cylindrical shape as a whole, and is slidable in the guide 18 along the axis. A projecting portion 26 is formed at the tip of the ignition pin 24 (the end on the left side in FIG. 1). When the ignition pin 24 moves to the side of the bottom wall 14 of the sensor cover 12, It projects to the outside from a through hole 16 formed in the wall 14. On the other hand, a flange portion 28 is formed at the other end of the ignition pin 24. The outer diameter of the collar portion 28 corresponds to the inner diameter of the guide 18, so that the ignition pin 24 is slidably held in the guide 18 and is held without play.

A firing spring 30 is arranged between the ignition pin 24 and the plate 20, and always urges the ignition pin 24 toward the through hole 16.

On the other hand, an inertial mass body 32 is arranged between the sensor cover 12 and the guide 18. The inertial mass body 32 is formed in a cylindrical shape corresponding to the inner diameter of the sensor cover 12 and the outer diameter of the guide 18, and is movably arranged along the axis between the sensor cover 12 and the guide 18. . A step portion 34 is formed on the inner wall of the inertial mass body 32. Further, a trigger spring 36 is arranged between the inertial mass body 32 and the bottom wall 14 of the sensor cover 12, and always urges the inertial mass body 32 toward the plate 20.

A trigger pawl 38 is arranged between the inertial mass body 32 and the guide 18. The trigger pawl 38 is formed in a substantially L shape, and one end of the L shape is rotatably supported by a shaft 40. The L-shaped tip portion 42 corresponds to the through hole 22 of the guide 18 and can penetrate the through hole 22 and project into the guide 18. That is, by rotating the trigger pawl 38 around the shaft 40, the tip 42 can pass through the through hole 22 of the guide 18 to approach or separate from the ignition pin 24. When the trigger pawl 38 is rotated and the tip 42 penetrates through the through hole 22 of the guide 18 and projects into the guide 18, the tip 42 engages with the flange 28 of the ignition pin 24 to cause the firing. The projecting portion 26 holds the ignition pin 24 urged by the spring 30 at a position separated from the through hole 16. An inclined surface 44 is formed at the corner of the trigger pawl 38. The inclined surface 44 corresponds to the stepped portion 34 of the inertial mass body 32 described above, and the state in which the trigger pawl 38 is rotated and the tip end portion 42 is pulled out from the through hole 22 of the guide 18 (that is, the ignition pin 24). In the state where the holding of the step is released), the stepped portion 34 contacts the inclined surface 44.

Further, normally, the inertial mass body 32 is located at a position closest to the plate 20 by the trigger spring 36, and in this state, the step portion 34 of the inertial mass body 32 is in contact with the trigger pawl 38, The tip portion 42 of the trigger pawl 38 penetrates the through hole 22 of the guide 18 and projects into the guide 18 to engage with the flange portion 28 of the ignition pin 24, so that the protrusion 26 of the ignition pin 24 is separated from the through hole 16. It is in the state of being held at the specified position.

The acceleration sensor 10 having the above-described configuration is attached to, for example, a gas generator 50 for a pretensioner.

In the gas generator 50, a gas generating agent 54 is contained in a main body 52 formed in a cylindrical shape, and a detonator 56 for igniting and burning the gas generating agent 54 is further arranged. The detonator 56 is located at the axial center of the main body 52, and the acceleration sensor 10 is assembled with the detonator 56 facing the detonator 56 with a shield ring 58 interposed therebetween, and is sealed and fixed by a plate 60. Therefore, when the acceleration sensor 10 is assembled to the main body 52, the through hole 16 of the sensor cover 12 faces the detonator 56, and the protrusion 26 of the ignition pin 24 that can project from the through hole 16 is the detonator 5. It is possible to collide with 6.

Next, the operation of this embodiment will be described. In the acceleration sensor 10 of the present embodiment configured as described above, normally, as shown in FIG. 1, the ignition pin 24 resists the biasing force of the firing spring 30 and the detonator 56 (transmission of the sensor cover 12). The trigger pawl 38 is positioned away from the hole 16), and the tip end 42 of the trigger pawl 38 penetrates the through hole 22 of the guide 18 and projects into the guide 18, and engages with the flange portion 28 of the ignition pin 24 to hold the ignition pin 24. is doing. Further, the inertial mass body 32 enters the position closest to the plate 20 by the trigger spring 36, that is, the rotation trajectory of the trigger pawl 38, and the step portion 34 abuts on the upper surface of the trigger pawl 38 to rotate the trigger pawl 38. It is blocked and the ignition pin holding state is maintained.

Here, when a large acceleration acts on the acceleration sensor 10, the inertial mass body 32 inertially moves in the direction of arrow A in FIG. 1 and separates from the rotation trajectory of the trigger pawl 38 to rotate around the axis 40 of the trigger pawl 38. It becomes possible to move. Therefore, the trigger pawl 38 pressed by the firing pin 24 urged by the firing spring 30 in the direction away from the ignition pin 24 is rotated in the direction away from the ignition pin 24. As a result, the tip end portion 42 of the trigger pawl 38 is separated from the collar portion 28 of the ignition pin 24 and slips out of the through hole 22 of the guide 18 to release the holding of the ignition pin 24. Therefore, the ignition pin 24 of the firing spring 30 is released. The urging force moves in the axial direction, the convex portion 26 projects from the through hole 16, collides with the detonator 56, and the detonator 56 is ignited.

As a result, the gas generating agent 54 of the gas generator 50 is ignited and combusted, and the pretensioner is operated, for example.

In this case, when the acceleration sensor 10 once operates and the ignition pin 24 moves, the step portion 34 of the inertial mass body 32 comes into contact with the inclined surface 44 of the trigger pawl 38, and therefore, the trigger pawl 38. Is in a state of being pressed in the direction of approaching the ignition pin 24 by the inertial mass body 32 urged by the trigger spring 36 (state shown in FIG. 2).

Here, in order to make the acceleration sensor 10 that has been operated once again ready for operation (reset), by moving the ignition pin 24 in the axial direction against the biasing force of the firing spring 30, It can be reset.

That is, as shown in FIG. 2, the ignition pin 24 with the protrusion 26 protruding from the through hole 16 is pressed from the outside of the sensor cover 12 by using the jig X, and the inside of the guide 18 (see FIG. 2 Move in the direction of arrow B).

In this case, since the trigger pawl 38 is pressed toward the ignition pin 24 by the inertial mass body 32 biased by the trigger spring 36 as described above, the ignition pin 24 reaches the initial position. At this point, the trigger pawl 38 rotates in the direction of approaching the ignition pin 24, and the tip end 42 of the trigger pawl 38 penetrates the through hole 22 of the guide 18 again and projects into the guide 18, so that the trigger pawl 38 comes into contact with the flange 28 of the ignition pin 24. Engages and holds the firing pin 24 in an initial position spaced from the through hole 16. Further, with the rotation of the trigger pawl 38, the stepped portion 34 of the inertial mass body 32 moves from the inclined surface 44 of the trigger pawl 38 to the upper surface and comes close to the plate 20 again, that is, the rotation of the trigger pawl 38. After entering the movement trajectory, the trigger pawl 38 returns to the initial state in which the rotation of the trigger pawl 38 is blocked.

As described above, in the acceleration sensor 10, it is possible to return to the initial state in which the trigger pawl 38 rotates to hold the ignition pin 24 by simply pressing the ignition pin 24 from the outside to move it to the initial position. . Therefore, for example, even when the operation inspection is performed before the acceleration sensor 10 is attached to the gas generator 50, it is easy to normally attach the acceleration sensor 10 to the gas generator 50 to make it operable (reset). Can be implemented.

Although the acceleration sensor 10 in this embodiment is used for the gas generator 50 for the pretensioner, it is not limited to this and can be naturally applied to other devices that operate by collision of the ignition pin 24. Is.

[0033]

[Effect of device]

 As described above, the acceleration sensor according to the present invention has a simple structure and has an excellent effect that it can be easily reset after performing an operation inspection for confirming the sensitivity without sacrificing the operability. Have.

[Brief description of drawings]

FIG. 1 is a sectional view showing an initial state of an acceleration sensor according to the present invention.

FIG. 2 is a cross-sectional view showing a state after the acceleration sensor operates.

[Explanation of symbols]

 10 Acceleration Sensor 24 Ignition Pin 26 Convex Part 28 Collar Part 30 Firing Spring 32 Inertial Mass Body 34 Step Part 36 Trigger Spring 38 Trigger Pawl 40 Shaft 42 Tip 44 Inclination 56 56 Detonator

Claims (1)

[Scope of utility model registration request] 1. Arranged so as to be movable along the axial direction,
An ignition pin that moves in the axial direction by the urging force of the firing spring to ignite the detonator, and a pivot that is rotatably supported in a direction toward and away from the ignition pin, and rotates in a direction toward the ignition pin. In the state, the ignition pin is separated from the detonator against the biasing force of the firing spring while being pressed by the ignition pin biased by the firing spring in a direction away from the ignition pin. And a trigger pawl that allows the ignition pin to move when rotated in a direction away from the ignition pin; The trigger pawl is urged in the direction of entering the pivot locus to penetrate the trigger pawl pivot locus. In this state, the trigger pawl is engaged to prevent the trigger pawl from rotating around the support shaft to maintain the ignition pin holding state. An inertial mass body that releases the rotation prevention of the trigger pawl to enable the trigger pawl to rotate around a support shaft and presses the trigger pawl in a direction approaching the ignition pin by the urging force of the trigger spring; Acceleration sensor.