JPH07108895A - Acceleration sensor - Google Patents

Abstract

PURPOSE:To prevent the timing for disengaging from an ignition pin a first and second trigger means for the inertial mass of an acceleration sensor from being advanced or retarded because of the wear of mating surfaces by allowing the second trigger means to be oscillated by the action of an acceleration less than a predetermined value, while locking the first trigger means so that it does not oscillate. CONSTITUTION:When an acceleration sensor 10 is exerted with an acceleration less than a predetermined value, an inertial mass 40 makes slight inertial movement from its original position; a trigger lever 42 oscillates in the direction of arrow A and in the opposite direction, while a trigger arm 48 does not oscillate; that is, the mating surfaces of the claw portion 46 of the trigger lever 42 and the end portion 48A of the trigger arm 48 oscillate, while the mating surfaces of the claw portion 52 of the trigger arm 48 and the flange portion 37 of an ignition pin 30 do not shake. Because of an energizing for exerted by a firing spring 38, a pressure working on the mating surfaces of the claw portion 46 of the trigger lever 42 and the end portion 48A of the trigger arm 48 is small compared with that working on the mating surfaces of the claw portion 52 of the trigger arm 48 and the flange portion 37 of the ignition pin 30.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an acceleration sensor which senses a sudden deceleration of a vehicle and actuates an actuator such as an airbag.

[0002]

2. Description of the Related Art Conventionally, there is an air bag device in which an ignition pin for inflating an air bag body by burning a gas generating substance enclosed in an inflator is driven by a mechanical ignition type sensor when the vehicle rapidly decelerates. .

As shown in FIG. 5, this acceleration sensor 7
At 0, the drive shaft 74A of the trigger means 74 swings in the arrow V direction by the ball 72 as an inertial mass body that moves according to a predetermined acceleration.
Further, the ignition pin 7 urged in the direction of the arrow W by the coil spring 76 is attached to the engaging portion 74B of the trigger means 74.
The collar part 78A of 8 is engaging. Therefore, when the ball 72 moves according to the predetermined acceleration and the drive shaft 74A swings in the direction of arrow V, the engaging portion 74 of the trigger means 74 is moved.
B swings integrally, and the engagement between the engagement portion 74B and the collar portion 78A of the ignition pin 78 is released, whereby the ignition pin 78 moves in the arrow W direction by the biasing force of the coil spring 76, It hits a detonator (not shown), and as a result, the gas generating substance burns.

[0004]

However, in the above acceleration sensor 70, the engaging portion 74B of the trigger means 74 is used.
Since the collar portion 78A of the ignition pin 78 that is biased in the direction of the arrow W by the coil spring 76 is engaged with the ball 72, when the load of a predetermined value or more is applied to the ball 72, the biasing force of the coil spring 76 is increased. Under action, the trigger means 7
The engaging portion 74B of No. 4 and the collar portion 78A of the ignition pin 78 slide. Therefore, the engagement surface is easily worn, and the engagement surface is worn, so that the timing at which the engagement portion 74B of the trigger means 74 and the collar portion 78A of the ignition pin 78 are released does not differ. It is necessary to consider the material and processing of parts.

In view of the above facts, the present invention has an object to obtain an acceleration sensor whose ignition timing is not easily deviated.

[0006]

An acceleration sensor of the present invention according to claim 1 is an inertial mass body that inertially moves from an original position when an acceleration of a predetermined value or more is applied, an ignition pin for collision with an ignition powder, and an ignition. An urging means for urging the pin in the direction of collision with the igniting agent, and an engaging position for engaging the ignition pin, and an engaging position for preventing movement of the ignition pin in the direction of collision with the igniting agent, By an urging force of the urging means, the ignition pin can be swung to an engagement disengagement position that allows the ignition pin to move in the collision direction with respect to the ignition charge, and the ignition pin receives the urging force in the collision direction with respect to the ignition charge. It has the 1st trigger means which receives rocking | fluctuation force from an engagement position to an engagement disengagement position, and the engagement part which engages with this 1st trigger means, and this engagement part engages with the 1st trigger means. The lock position for holding the first trigger means in the engagement position, the engagement portion and the first position An unlock position where the engagement with the trigger means is released and the first trigger means can swing to the disengagement position, and a swing position to which the first trigger means can swing from the lock position to the unlock position by the movement of the inertial mass body. And a second trigger means that swings to.

[0007]

In the acceleration sensor of the present invention according to claim 1,
When an acceleration less than a predetermined value acts, the inertial mass body slightly moves from its original position. In this case, the movement of the inertial mass causes the second trigger means to swing, but the first trigger means does not swing. That is, the engaging part of the second trigger means and the first
The engagement surface of the first trigger means and the engagement surface of the ignition pin do not slide. Therefore, there is no wear on the engagement surface between the engagement portion of the first trigger means and the ignition pin, and the ignition timing does not shift even if the engagement surface is a general metal.

Further, by the urging force of the urging means, the first
The pressure acting on the engaging surface between the engaging portion of the second trigger means and the first trigger means is smaller than the pressure acting on the engaging surface between the engaging portion of the trigger means and the ignition pin. It is also possible to increase the moving force of the small inertial mass body while reducing the wear of the engaging surface between the engaging portion of the second trigger means and the first trigger means, and reducing the deviation of the ignition timing due to this wear. can do.

[0009]

EXAMPLE An acceleration sensor 10 according to a first example of the present invention.
Will be described with reference to FIGS. 1 and 2.

As shown in FIG. 2, the acceleration sensor 10
Has a sensor cover 12. Sensor cover 12
Is formed into a substantially cylindrical shape having a bottom wall 14 at one end, and a through hole 16 is formed in the bottom wall 14 on the axis.
Inside the sensor cover 12, the body block 1
8 and a lid block 20 are arranged. The body block 18 is formed in a substantially cylindrical block shape, and the bottom wall 22 is connected and fixed to the bottom wall 14 of the sensor cover 12. Further, the lid block 20 is formed in a disk shape, and an O is provided between the sensor cover 12 and the lid block 20.
A ring 24 is arranged to ensure a hermetic seal. The body block 18 may be divided into a plurality of parts for the convenience of manufacture or assembly.

A through hole 26 coaxial with the through hole 16 is formed in the bottom wall 22 of the body block 18 and corresponds to an ignition pin 30 described later.

As shown in FIG. 1, the body block 1
An ignition pin 30 is arranged inside the shaft 8 coaxially with the axis P1 of the acceleration sensor 10. This ignition pin 30
The holder 36 is disposed behind the inertial mass 40, which will be described later, on the opposite side of the moving direction (the direction of arrow B) when acceleration acts. The ignition pin 30 has a cylindrical shape and has a through hole 2
It is guided by 6 and is movable in the right direction of FIG. 1 (direction of arrow F).

As shown in FIG. 1, the end portion of the ignition pin 30 on the side of the bottom wall 22 is formed as a pointed portion 34.
When the ignition pin 30 moves to the side of the bottom wall 22 of the body block 18 most (the state of the imaginary line in FIG. 1), it protrudes to the outside from the through hole 26 formed in the bottom wall 22.

On the other hand, the end portion 30A of the ignition pin 30 on the side of the lid block 20 is inserted into a recess 36A having a circular cross section formed in the holder 36. A brim portion 37 is formed at an intermediate portion in the longitudinal direction of the ignition pin 30. Between the brim portion 37 and the bottom portion of the recess 36A, the ignition pin 30 acts in the direction of collision with the detonator 90 as an ignition charge. A firing spring 38 as an urging means for urging is arranged and always urges the ignition pin 30 in the direction of the bottom wall 22 (through hole 26) (direction of arrow F).

The inertial mass body 40 has a spherical shape, is movably held in the case 41, and inertially moves in the direction of arrow B from its original position (the position shown by the solid line in FIG. 1) when an acceleration of a predetermined value or more is applied. To do.

Further, the case 41 is arranged in the body block 18 along the direction of the axis P1 and is held by the holder 36.
It is cylindrical with a bottom on the side.

A trigger lever 42 as a second trigger means is in contact with the outer periphery of the inertial mass body 40 on the side of the lid block 20. The trigger lever 42 has a rectangular plate shape, and a shaft portion 44 projects outward in the width direction at both lower ends of FIG. These shaft portions 44 are held in shaft supporting holes formed in the body block 18, whereby the trigger lever 42 is rotated in the counterclockwise direction from the position shown in FIG. ) Can be rotated. In addition, the inertial mass body 4 of the trigger lever 42
A claw portion 46 as an engaging portion projects in the vicinity of the lower end portion of the contact surface 42A with 0, and the side surface of the shaft portion 44 of the claw portion 46 has a trigger arm 48 as a first trigger means. One end 48A is engaged.

The trigger arm 48 extends toward the bottom wall 22 along the axis P1 of the acceleration sensor 10, and further the axis P.
The end portion 48B on the side of the bottom wall 22 is bent toward 1.
It reaches the vicinity of the brim portion 37 of the ignition pin 30. Further, a shaft portion 50 projects outward from the end portion 48B of the trigger arm 48 in the width direction. These shafts 50 are held in shaft support holes formed in the body block 18, whereby the trigger arm 48 rotates clockwise from the position shown in FIG. 1 (direction of arrow C) about the shaft 50. It can be rotated to. By the rotation of the trigger lever 42 in the direction of arrow A, the claw portion 46 of the trigger lever 42 does not affect the rotation of the trigger arm 48, that is, the direction along the engagement surface with the end portion 48A of the trigger arm 48. Swing in the direction.

At the end portion 48B of the trigger arm 48, a claw portion 52 is formed as an engaging portion toward the brim portion 37 of the ignition pin 30, and the claw portion 52 is provided at the brim portion 3 of the ignition pin 30.
The ignition pin 30 urged by the firing spring 38 in the state in which the ignition pin 7 is engaged with the
It is held at a position separated from 6 (the position indicated by the solid line in FIG. 1). Further, the engagement between the claw portion 52 and the flange portion 37 of the ignition pin 30 causes the trigger lever 42 to rotate in the direction of arrow A about the shaft portion 44 and the trigger arm 48 to rotate about the shaft portion 50. It is designed to be released when it is rotated in the direction of arrow C.

The length L1 of the claw portion 52 from the shaft portion 50
Is set to be shorter than the length L2 of the trigger arm 48, so that the engagement surface between the claw portion 52 of the trigger arm 48 and the collar portion 37 of the ignition pin 30 is urged by the urging force of the firing spring 38. Compared to the acting pressure,
The pressure acting on the engagement surface between the claw portion 46 of the trigger lever 42 and the end portion 48A of the trigger arm 48 is small.

A bias spring 53 is arranged between the end portion 42A of the trigger lever 42 and the lid block 20, and always urges the inertial mass body 40 toward the bottom wall 22. The inertial mass body 40 can move in the left direction (direction of arrow B) in FIG. 1 against the biasing force of the bias spring 53 by the inertial force when a predetermined acceleration is applied.

As shown in FIG. 2, the end 4 of the arm 42 is
The arm 42 is provided at a portion of the lid block 20 facing 2A.
A cylindrical protruding portion 43 is formed toward the side, and the notch 43 from the arm 42 side is formed in the outer peripheral portion of the protruding portion 43.
A is formed. A release lever 72 is held between an end 43B of the protrusion 43 on the arm 42 side and an end 42A of the arm 42. The release lever 72 has a cylindrical shape, and an engaging piece 72A that can be fitted into the notch 43A is formed on the outer peripheral portion.

The release lever 72 is supported on one end of the shaft 74 and is designed to rotate integrally with the shaft 74. In addition, the shaft 74 has the protruding portion 43.
And the support hole 76 of the lid block 20. Shaft 7 protruding outward from support hole 76 of lid block 20
A pin 80 is attached to the tip of the shaft 4, and the shaft 74, that is, the release lever 72 can be rotated from the outside.

A torsion spring 82 is provided between the pin 80 and the lid block 20 to urge the shaft 74 (in the direction of arrow B). Therefore, the shaft 74
When the locking piece 72A of the release lever 72 is fitted into the notch 43A of the protruding portion 43, the release lever 72 moves in the direction of arrow B and the release lever 72 separates from the end 42A of the arm 42. Inertia mass 40 and arm 4
2 becomes movable in the direction of arrow B.

The acceleration sensor 10 having the above structure is inserted into the cylindrical case 87 and is assembled to, for example, a gas generator for a pretensioner (detailed structure is not shown). A gas generating agent is stored in the gas generator, and an enhancer 89 is stored in the vicinity of the bottom portion 87A of the cylindrical case 87 surrounded by the gas generating agent. Further, through holes 87B are formed in the outer peripheral portion in the vicinity of the bottom portion 87A of the cylindrical case 87, and the enhancer 89 ignites the gas generating agent through these through holes 87B.

A detonator 90 is provided in the cylindrical case 87 between the acceleration sensor 10 and the enhancer 89. This detonator 90 includes an enhancer 89 and a sensor cover 1.
It is fixed to the detonator piece 92 that is sandwiched between the second bottom wall 14 and the through hole 26 formed in the bottom wall 22 of the body block 18 described above in a state where the acceleration sensor 10 is assembled. There is. The acceleration sensor 10 is fixed by the support ring 94 in this state.
An O-ring 96 is arranged between the sensor cover 12 and the mounting portion of the gas generator to ensure hermetic sealing. Therefore, when the acceleration sensor 10 is assembled to the gas generator, the pointed portion 34 of the ignition pin 30 that can project from the through hole 26 formed in the bottom wall 22 of the body block 18 can collide with the detonator 90. There is.

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 by the solid line in FIG. 1, the ignition pin 30 resists the biasing force of the firing spring 38 and detonator 90 (of the body block 18). At a position separated from the through hole 26), the claw portion 52 engages with the collar portion 37 of the ignition pin 30, and the claw portion 46 of the trigger lever 42 engages with the end portion 48A of the trigger arm 48. The ignition pin 30 is held at the position indicated by the solid line in FIG.

Further, the inertial mass body 40 and the trigger lever 4
2 is located at a position closest to the bottom wall 22 by the bias spring 53, and prevents the trigger lever 42 from rotating and maintains the ignition pin holding state.

Further, by the torsion spring 82,
Locking piece 72A of the release lever 72 biased in the direction of arrow B
Comes into contact with the end portion 43B of the protruding portion 43, and the release lever 72
Is sandwiched between the protruding portion 43 and the end portion 42A of the arm 42, and the movement of the inertial mass body 40 is prevented.

Here, the shaft 74 is rotated around the axis,
When the locking piece 72A of the release lever 72 is fitted in the notch 43A of the protrusion 43, the release lever 72 moves in the direction of arrow B, and the inertial mass body 40 and the arm 42 can move in the direction of arrow B. Becomes As a result, the acceleration sensor 10 is set in an operable state.

When an acceleration of less than a predetermined value acts on the acceleration sensor 10 in such a state, the inertial mass body 40 slightly inertially moves from the original position (the position indicated by the solid line in FIG. 1). In this case, the movement of the inertial mass body 40 causes the trigger lever 42 to move.
Swings in the direction of arrow A and in the opposite direction, but the claw portion 46 of the trigger lever 42 moves the end portion 48A of the trigger arm 48.
Since the trigger arm 42 swings in the direction along the engagement surface of the trigger lever 42, the trigger arm 48 does not swing in the direction of arrow C due to the swing of the trigger lever 42. That is, the engagement surface between the claw portion 46 of the trigger lever 42 and the end portion 48A of the trigger arm 48 slides, but the engagement surface between the claw portion 52 of the trigger arm 48 and the flange portion 37 of the ignition pin 30 slides. It doesn't move. Therefore, the engagement surface between the claw portion 52 of the trigger arm 48 and the flange portion 37 of the ignition pin 30 is unlikely to wear.

Further, the length L1 of the claw portion 52 from the shaft portion 50
Is set shorter than the length L2 of the trigger arm 48, the pressure acting on the engagement surface between the claw portion 52 of the trigger arm 48 and the flange portion 37 of the ignition pin 30 by the urging force of the firing spring 38. Compared with, the pressure acting on the engagement surface between the claw portion 46 of the trigger lever 42 and the end portion 48A of the trigger arm 48 is small, and the claw portion of the trigger arm 48 is increased while increasing the moving force of the small inertial mass body 40. 52 can be transmitted.

On the other hand, when an acceleration of a predetermined value or more is applied to the acceleration sensor 10, the trigger lever 42 pressed by the inertial mass body 40 in the direction of arrow B rotates about the shaft portion 44 in the direction of arrow A. Therefore, the engagement between the claw portion 46 and the end portion 48A of the trigger arm 48 is released, and the trigger arm 48 becomes rotatable around the shaft portion 50 in the direction of arrow C from the position shown in FIG.

Therefore, the ignition pin 30 urged by the firing spring 38, the trigger arm 48,
The shaft 50 is rotated in the direction of the arrow C from the position shown in FIG. 1 around the shaft 50, whereby the claw 52 is disengaged from the flange 37 of the ignition pin 30, and the ignition pin 30 is bottomed by the urging force of the firing spring 38. It moves in the direction of the wall 22, the point 34 projects from the through hole 26, collides with the detonator 90, and
0 is ignited. As a result, the enhancer 89 is ignited, the gas generating agent is subsequently ignited and combusted, and the pretensioner is operated, for example.

As described above, in the acceleration sensor 10 of this embodiment, the engagement surface between the claw portion 52 of the trigger arm 48 and the collar portion 37 of the ignition pin 30 is hard to wear, and the claw portion 46 of the trigger lever 42 and the trigger. The wear of the engagement surface with the end portion 48A of the arm 48 is small. Therefore, the ignition timing does not shift even if each engagement surface is made of general metal. Further, as compared with the pressure acting on the engagement surface between the claw portion 52 of the trigger arm 48 and the collar portion 37 of the ignition pin 30 by the urging force of the firing spring 38, the claw portion 46 of the trigger lever 42 and the trigger arm 48 are compared. The pressure acting on the engagement surface with the end portion 48A is small, and while increasing the moving force of the small inertial mass body 40,
It is possible to reduce wear of the engagement surface between the claw portion 46 of the trigger lever 42 and the end portion 48A of the trigger arm 48, and reduce the deviation of the ignition timing due to this wear.

Further, in this embodiment, the trigger arm 48
However, since the trigger arm 48 is arranged along the arrow B direction, the rotation of the trigger arm 48 in the arrow C direction is hardly affected by the acceleration in the arrow B direction, and the deviation of the ignition timing due to the acceleration in the arrow B direction is small.

Next, an acceleration sensor 10 according to a second embodiment of the present invention will be described with reference to FIGS.

Regarding the same members as in the first embodiment,
The same reference numerals are given and the description thereof is omitted.

As shown in FIGS. 3 and 4, in the inertial mass body 100 of this embodiment, the movement locus P2 is the acceleration sensor 1
It is parallel to the axis P1 of 0, that is, the movement locus of the ignition pin 30. Therefore, the length L3 of the trigger lever 42 is longer and the length L2 of the trigger arm 48 is longer than that of the first embodiment.
Is getting shorter. Therefore, in this embodiment, the total length of the acceleration sensor 10 can be shortened.

Note that this embodiment also has the same effects as the first embodiment. That is, the claw portion 5 of the trigger arm 48
2 and the engaging surface between the flange 37 of the ignition pin 30 are not easily worn,
The wear of the engagement surface between the claw portion 46 of the trigger lever 42 and the end portion 48A of the trigger arm 48 is small. Therefore, the ignition timing does not shift even if each engagement surface is made of general metal.

Further, as compared with the pressure applied to the engagement surface between the claw portion 52 of the trigger arm 48 and the collar portion 37 of the ignition pin 30 by the urging force of the firing spring 38,
The pressure acting on the engagement surface between the claw portion 46 of the trigger lever 42 and the end portion 48A of the trigger arm 48 is small, and the claw portion 46 of the trigger lever 42 and the trigger arm 48 are increased while increasing the moving force of the small inertial mass body 40. It is possible to reduce the wear of the engagement surface with the end portion 48A of and to reduce the deviation of the ignition timing due to this wear.

[0042]

As described above, the acceleration sensor according to the present invention includes an inertial mass body that inertially moves from its original position when an acceleration of a predetermined value or more is applied, an ignition pin for collision with an ignition powder,
Urging means for urging the ignition pin in the direction of collision with the ignition powder,
An engaging position that has an engaging portion that engages with the ignition pin, and an engaging position that prevents the ignition pin from moving in the direction of collision with the ignition agent, and an urging force of the urging means moves the ignition pin in the direction of collision with the ignition agent. First trigger means that is swingable to an movable disengagement position and that receives an oscillating force from the engagement position to the disengagement position by the urging force of the ignition pin in the direction of collision with the ignition charge. A lock position for engaging the first trigger means with the engagement portion, the engagement portion engaging with the first trigger means for holding the first trigger means in the engagement position, and An unlocked position where the engagement between the engagement portion and the first trigger means is released and the first trigger means can swing to the disengaged position;
Second trigger means that can be swung to and is swung from the locked position to the unlocked position by the movement of the inertial mass body;
Since it is configured to have, there is an excellent effect that the ignition timing is hard to shift.

[Brief description of drawings]

FIG. 1 is a side sectional view showing an acceleration sensor according to a first embodiment of the present invention.

FIG. 2 is an exploded perspective view showing the acceleration sensor according to the first embodiment of the present invention.

FIG. 3 is a side sectional view showing an acceleration sensor according to a second embodiment of the present invention.

FIG. 4 is an exploded perspective view showing an acceleration sensor according to a second embodiment of the present invention.

FIG. 5 is an exploded perspective view showing an acceleration sensor according to a conventional example.

[Explanation of symbols]

 10 Acceleration Sensor 30 Ignition Pin 38 Firing Spring (Biasing Means) 40 Inertial Mass Body 42 Trigger Lever (Second Trigger Means) 46 Claw (Engagement) 48 Trigger Arm (First Trigger Means) 52 Claw (Engagement part) 90 detonator (igniter) 100 inertial mass body

Claims (1)

[Claims] 1. An inertial mass body that inertially moves from its original position when an acceleration of a predetermined value or more is applied, an ignition pin for collision with an ignition powder, and an urging means for urging the ignition pin in a direction of collision with the ignition powder. An engaging position that has an engaging portion that engages with the ignition pin, and an engaging position that prevents the ignition pin from moving in the direction of collision with the ignition agent, and an urging force of the urging means moves the ignition pin in the direction of collision with the ignition agent. A first trigger that is swingable to an engagement disengagement position that is movable and that receives the swinging force from the engagement position to the disengagement position by the biasing force that the ignition pin receives in the direction of collision with the ignition charge. Means and an engaging portion for engaging the first trigger means, the engaging portion engaging with the first trigger means and holding the first trigger means in the engaging position; The engagement between the engaging portion and the first trigger means is released and the first trigger means is engaged. An unlock position capable of swinging to a release position, and a second trigger means capable of swinging to the swing position and swinging from the lock position to the unlock position by the movement of the inertial mass body, Acceleration sensor.