JPH07108897A - Ignition pin for use in acceleration sensor - Google Patents

Abstract

PURPOSE:To reduce the cost of machining for an acceleration sensor which releases a trigger member with the oscillation of an inertial mass according to a predetermined acceleration to force an ignition pin into collision with a detonator by forming the pointed portion of the ignition pin into a pyramid. CONSTITUTION:A pointed portion 34 is secured to that side of the ignition pin 30 of an acceleration sensor 10 which corresponds to the bottom wall 22 of a body block 18, and the pointed portion 34 is formed by the cutting of the end portion of a plate of a square cross section into a regular pyramid and, when moved closest to the bottom wall 22 of the body block 18, projects to the outside from a through hole 26 formed in the bottom wall 22. To manufacture the ignition pin 30, the end portion of the plate is cut at four planes whereby the pointed portion 34 in the form of a regular pyramid can easily be formed. The ignition pin therefore has such an excellent effect that it allows easy machining as compared with a conventional one that is formed of a cylindrical shaft whose end portion is shaved into a conical pointed portion.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ignition pin for an acceleration sensor used for an acceleration sensor that 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 acceleration sensor senses a rapid deceleration of a vehicle and an ignition pin burns a gas generating substance enclosed in an inflator to inflate an air bag body.

As shown in FIG. 6, this acceleration sensor 7
At 0, the drive shaft 74A of the trigger member 74 swings in the direction of arrow V by the ball 72 as an inertial mass body that moves according to a predetermined acceleration.
Further, the ignition pin 7 urged in the arrow W direction by the coil spring 76 is attached to the engaging portion 74B of the trigger member 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 member 74 is moved.
B integrally swings, and the engagement between the engaging portion 74B and the brim portion 78A of the ignition pin 78 is released, whereby the ignition pin 78 moves in the arrow W direction by the urging force of the coil spring 76, and is illustrated. The gas generator is burned as a result.

[0004]

However, in the acceleration sensor 70 described above, the tip of the cylindrical shaft member 80 whose ignition pin 78 is shown by a solid line in FIG. 7 is shown by an imaginary line in FIG. It is sharpened into a conical shape to form a point 82. For this reason, there is a problem that the machining cost of the tip portion of the ignition pin increases.

In view of the above facts, an object of the present invention is to obtain an ignition pin for an acceleration sensor which can reduce the processing cost.

[0006]

The ignition pin for an acceleration sensor according to the present invention as defined in claim 1 is characterized by having a pointed portion in the shape of a pyramid.

[0007]

According to the ignition pin for an acceleration sensor of the present invention described in claim 1, when manufacturing the ignition pin, the pyramidal point can be easily formed by cutting the plate material with a flat surface. Therefore, as compared with the conventional ignition pin for an acceleration sensor in which the tip of a cylindrical shaft member is cut into a conical shape to form a point, the machining is easier and the machining cost can be reduced.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An acceleration sensor 10 using an ignition pin for an acceleration sensor according to a first embodiment of the present invention will be described with reference to FIGS.

As shown in FIG. 1, 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.

Inside the body block 18, an ignition pin 30 is arranged coaxially with the axis P1 of the acceleration sensor 10. The position of the ignition pin 30 is the acceleration sensor 1
It may be deviated from the axis P1 of 0. This ignition pin 30
Is disposed with the holder 36 sandwiched behind the inertial mass body 40, which will be described later, on the side opposite to the moving direction (direction of arrow B) at the time of acceleration action. The ignition pin 30 includes a base portion 33 and a point portion 34, and the base portion 33 is slidably arranged in a guide groove 32 formed in the body block 18. Therefore, the ignition pin 30 is connected to the acceleration sensor 10
Is movable along the axis P1 direction.

The ignition pin 30 has a body block 18
The pointed portion 34 is fixed to the side corresponding to the bottom wall 22 of the sheet.
It is formed by cutting into a quadrangular pyramid as shown in FIG. Further, the tip 34 of the ignition pin 30 moves to the outside from the above-mentioned through hole 26 formed in the bottom wall 22 in the state of being moved to the side of the bottom wall 22 of the body block 18 (the state of the imaginary line in FIG. 2). Project to.

On the other hand, the ignition pin 30 is formed with a recess 30A having a circular cross section along the axis from the other end on the opposite side. The recess 30A has a cylindrical holder formed in the body block 18. 36 has been inserted. A firing spring 38 as an urging means for urging the ignition pin 30 in the direction of collision with the detonator 90 serving as an ignition charge is arranged between the holder 36 and the bottom of the recess 30A, and the ignition pin is always provided. 30 is urged in the direction of the bottom wall 22 (through hole 26) (direction of arrow F). In addition, the detonator 9
It is not limited to 0.

The inertial mass body 40 is arranged coaxially with the axis P1 of the acceleration sensor 10. The inertial mass body 40
The position of may shift from the axis P1 of the acceleration sensor 10. Further, the inertial mass body 40 has a spherical shape, is movably held in the case 41, and inertially moves in the arrow B direction from the original position (the position indicated by the solid line in FIG. 2) when an acceleration of a predetermined value or more is applied. .

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

On the outer circumference of the inertial mass body 40, one end portion 42A of the arm 42 which constitutes a part of the trigger means is in contact. A bias spring 44 is arranged between the end portion 42A and the lid block 20 and always urges the inertial mass body 40 toward the bottom wall 22 to hold it in the original position. The inertial mass body 40 can move in the left direction (direction of arrow B) in FIG. 2 against the biasing force of the bias spring 44 by the inertial force when a predetermined acceleration is applied. Also,
The method for holding the inertial mass body 40 in the original position is not limited to the bias spring 44, and other methods such as a structure in which the inertial mass body 40 is supported by an inclined surface and the inertial mass body 40 is held in the original position by gravity are also applicable. good.

The other end of the arm 42 extends toward the bottom wall 22 outside the case 41 above the inertial mass body 40 (the upper side in FIG. 2), and the trigger is provided at the tip 42B. The upper end 5 of the trigger lever 50 which constitutes another part of the means
0A is rotatably engaged.

As shown in FIG. 3, the trigger lever 50
Is formed in a U-shaped cross section by bending a plate material, and the intermediate portion 50B following the upper end portion 50A has an ignition pin 30.
The lower portion 50C has a flat plate shape and extends downward along the outer side of.

As shown in FIG. 2, a bearing portion 50D is formed on the lower surface of the lower portion 50C of the trigger lever 50, and the shaft 52 inserted in the bearing portion 50D causes
The trigger lever 50 is held in a shaft support hole 53 formed in the body block 18, whereby the trigger lever 50 rotates counterclockwise from the position shown in FIG.
It can be rotated to. Further, the upper surface of the lower portion 50C of the trigger lever 50 is an inclined surface that is positioned higher toward the inertial mass body 40 side, and the edge portion on the inertial mass body 40 side is an engaging claw portion 56.

As shown in FIG. 3, a block-shaped convex portion 30B is formed in the lower portion of the ignition pin 30 along the axial direction of the ignition pin 30. An engaging concave portion 54 is formed at an axially intermediate portion of the convex portion 30B, and an engaging claw portion 56 is engaged with the engaging concave portion 54.

As shown in FIG. 2, in the state where the engaging claw portion 56 is engaged with the engaging concave portion 54, the tip 34 of the ignition pin 30 urged by the firing spring 38 extends from the through hole 26. It is held at a separated position (position indicated by a solid line in FIG. 2). Further, the engagement between the engaging claw portion 56 and the engaging concave portion 54 is such that the trigger lever 50 moves around the shaft 52 with an arrow A
It is designed to be released when rotated in the direction.

As shown in FIG. 1, 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. 2, the ignition pin 30 resists the biasing force of the firing spring 38 and the detonator 90 (of the body block 18). The trigger claw portion 56 of the trigger lever 50 is located away from the through hole 26).
The engaging pin 54 is engaged to hold the ignition pin 30 at the position indicated by the solid line in FIG.

Further, the inertial mass body 40 and the arm 42 are located at the position closest to the bottom wall 22 by the bias spring 44, and prevent the trigger lever 50 from rotating and maintain 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 a large acceleration acts on the acceleration sensor 10 in such a state, the inertial mass body 40 is moved by the arrow B in FIG.
Inertia moves in the direction. In this case, the arm 42 moves in the arrow B direction integrally with the inertial mass body 40. Therefore, the trigger lever 50 engaged with the tip portion 42B of the arm 42
Is swung in the direction of arrow A.

As a result, the engaging claw portion 56 of the trigger lever 50 is separated from the engaging concave portion 54 of the ignition pin 30, and the holding of the ignition pin 30 is released. Therefore, the ignition pin 30 is moved by the urging force of the firing spring 38 to the bottom wall 22.
The cusp 34 projects from the through hole 26, collides with the detonator 90, and the detonator 90 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.

Here, when the ignition pin 30 of the acceleration sensor 10 is manufactured, the quadrangular pyramid-shaped pointed portion 34 can be easily formed by cutting the tip end portion of the plate material on four sides. Therefore, as compared with the conventional ignition pin for an acceleration sensor in which the tip of a cylindrical shaft member is cut into a conical shape to form a point, the machining is easier and the machining cost can be reduced.

Next, an ignition pin 100 for an acceleration sensor according to a second embodiment of the present invention will be described with reference to FIGS. 4 (A) and 4 (B).

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

As shown in FIG. 4 (A), in this embodiment, the ignition pin 100 has a base portion 102 and a pointed portion 104 which are made of a single plate material. Bottom 102 of base 102
A concave portion 106 for supporting the firing spring 38 is formed in A, and the bottom portion 10 of the base portion 102 is formed.
A pyramid-shaped pointed portion 104 is formed at one end of the surface 102B facing the 2A.

The apex 104 has a rectangular parallelepiped protrusion 108 shown by an imaginary line in FIG. 4A, and a first cut plane C1 passing through a corner M1 of the top surface 108A of the protrusion 108 and a corner M1. It is formed by cutting with a second cut plane C2 passing through, and the shape viewed from the top surface 108A direction (the arrow B direction in FIG. 4A) is as shown in FIG. 4B. There is.

Therefore, in this embodiment, the ignition pin 1
In the case of manufacturing 00, the pyramid-shaped pointed portion 104 can be easily formed by cutting one plate material on two surfaces. Therefore, as compared with the conventional ignition pin for an acceleration sensor in which the tip of a cylindrical shaft member is cut into a conical shape to form a point, the machining is easier and the machining cost can be reduced.

Next, an ignition pin 100 for an acceleration sensor according to a third embodiment of the present invention will be described with reference to FIGS. 5 (A) and 5 (B).

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

As shown in FIG. 5A, in this embodiment, the ignition pin 110 for the acceleration sensor has a base 112 and a point 1.
14 is composed of a single plate material. Base 11
On the bottom 112A of 2, the firing spring 38
A recess 116 for supporting the base 1 is formed.
12 has a pyramid-shaped pointed portion 1 on the side facing the bottom portion 112A.
14 is formed to project.

The apex 114 is formed by cutting one end 118 of the plate material indicated by an imaginary line in FIG. 5A by a cut plane C3 passing through a corner M2 of the top surface 118A of the end 118. The shape as viewed from the direction of the top surface 118A (direction of arrow B in FIG. 5A) is as shown in FIG. 5B.

Therefore, in this embodiment, the ignition pin 1
When manufacturing 10, the pyramidal point 114 can be easily formed by cutting one plate on one surface. Therefore, as compared with the conventional ignition pin for an acceleration sensor in which the tip of a cylindrical shaft member is cut into a conical shape to form a point, the machining is easier and the machining cost can be reduced.

[0044]

As described above, since the ignition pin for an acceleration sensor according to the present invention has a pyramid-shaped pointed portion, it has an excellent effect that the processing cost can be reduced.

[Brief description of drawings]

FIG. 1 is an exploded perspective view showing an acceleration sensor to which an ignition pin for an acceleration sensor according to a first embodiment of the present invention is applied.

FIG. 2 is a side sectional view showing an acceleration sensor to which an ignition pin for an acceleration sensor according to the first embodiment of the present invention is applied.

FIG. 3 is a sectional view taken along line 3-3 of FIG.

FIG. 4A is a perspective view showing an ignition pin for an acceleration sensor according to a second embodiment of the present invention, and FIG. 4B is a view of arrow B in FIG. 4A.

5A is a perspective view showing an ignition pin for an acceleration sensor according to a third embodiment of the present invention, and FIG. 5B is a view of arrow B in FIG. 5A.

FIG. 6 is an exploded perspective view showing an acceleration sensor according to a conventional example.

FIG. 7 is a perspective view showing an ignition pin for an acceleration sensor according to a conventional example.

[Explanation of symbols]

 10 Acceleration Sensor 30 Ignition Pin 33 Base 34 Tip 100 Acceleration Sensor Ignition Pin 102 Base 104 Tip 110 110 Acceleration Sensor Ignition Pin 112 Base 114 Tip

Claims (1)

[Claims] 1. An ignition pin for an acceleration sensor having a pyramidal point.