JPH07108898A - Safety device for acceleration sensor - Google Patents

Abstract

PURPOSE:To provide a safety device for an acceleration sensor, capable of preventing any unnecessary operation of the acceleration sensor without increasing an operating force for release. CONSTITUTION:A plate spring 72 having a fixing portion 72A fixed to the inner peripheral portion of a body block 18 is provided in a portion opposite to the recessed portion 40A of an inertial mass 40, the end portion of the plate spring 72 being curved to form an engagement portion 72B. A shaft 76 is provided in a portion opposite to the abutting portion 72C of the plate spring 72, and that end portion of the shaft 76 which is on the side of the plate spring 72 is pointed 76A into a conic shape. The shaft 76 is energized by a compression coil spring 79 toward the plate spring 72, and the plate spring 72 is made to undergo elastic deformation by the shaft 76 and engages with the inertial mass 40, stopping the inertial mass 40 from moving in the direction of arrow B.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention sets an inertial mass body for detecting an abrupt deceleration of a vehicle or the like and actuating an actuator such as an air bag to a movement-prevented state at the time of assembling the vehicle body, etc. The present invention relates to a safety device for an acceleration sensor that releases a movement blocking state after the end.

[0002]

2. Description of the Related Art An air bag device or the like mounted on a vehicle has a built-in acceleration sensor for detecting a sudden deceleration of the vehicle, and unnecessary operation due to a shock applied before completion of assembly of a steering wheel or the like to a vehicle body. To prevent this, a safety device is attached to prevent movement of the inertial mass.

As shown in FIG. 5, the safety device includes an inertial mass body 100 that moves leftward (in the direction of arrow L) in response to a predetermined acceleration, and is movable substantially parallel to the inertial mass body 100. , An advance position (solid line position) that has advanced on the movement path of the inertial mass body 100, a stopper member 102 that is movable from this advance position to a retracted position (imaginary line position), and this stopper member 102. The simplest structure is a structure that includes a bias spring 104 that biases the inertial mass body 100 in a direction opposite to the inertial movement direction (direction of arrow L).

In this acceleration sensor safety device, the stopper member 102 prevents the inertial mass body 100 from moving before the steering wheel or the like is assembled to the vehicle body, and after the assembly is completed, the stopper member 102 is released (not shown). The inertial mass body 100 is released from the movement blocking state by moving it in the direction of the arrow L with the lever and holding it in the retracted position. Therefore, in this movable state of the inertial mass body, when acceleration generated when the vehicle suddenly decelerates is applied to the inertial mass body 100, the inertial mass body 100 is damped and the bias spring 104 is applied.
Of the trigger lever 106 (in the case of a mechanical type) or the electric contact 108 provided on the movement locus of the inertial mass body 100 by moving in the inertial movement direction (arrow L direction) by overcoming the urging force of the inertial mass.
The air bag device is actuated by abutting (on electric type).

[0005]

However, in this acceleration sensor safety device, the movement of the inertial mass body 100 is caused by the spring 110 attached to the stopper member 102.
It is only blocked by the urging force of. Therefore, since it is necessary to use the spring 110 having a large biasing force, there is a problem that the operating force at the time of release becomes large.

In consideration of the above facts, an object of the present invention is to provide a safety device for an acceleration sensor which can prevent unnecessary operation of the acceleration sensor without increasing the operating force at the time of release.

[0007]

A safety device for an acceleration sensor according to a first aspect of the present invention is an inertial mass body that inertially moves from an original position when an acceleration of a predetermined value or more is applied, and a movement locus of the inertial mass body. Locking means movable along a direction to a locked position and an unlocked position, a fixed part fixed to the acceleration sensor main body side, an engaging part engaging with the inertial mass body, and a locking part of the locking means. An abutting portion located on a movement locus, and when the locking means moves to the locking position, the abutting portion is pressed by the locking means and the engaging portion moves on the movement locus of the inertial mass body. While entering from a direction different from the trajectory and engaging the inertial mass body,
When the locking means moves to the unlock position, the engagement portion has a stopper member that moves from a movement locus of the inertial mass body in a direction different from the movement locus to a retracted position.

[0008]

In the safety device for an acceleration sensor according to the first aspect of the present invention, when the lock means is moved to the lock position along the movement locus direction of the inertial mass body, the contact portion of the stopper member is pressed by the lock means. Then, the engaging portion enters the movement path of the inertial mass body from a direction different from the movement path and engages with the inertial mass body. Therefore, the movement of the inertial mass body is blocked by the stopper member, and the acceleration sensor can be prevented from operating.

When the inertial mass body tries to move in this state, this moving force acts in the direction of moving the engaging portion of the stopper member in the movement locus direction of the inertial mass body. Therefore, since the direction of this force is different from the releasing direction of the engaging portion, the pull-out force of the locking means is extremely small. Therefore, it is possible to prevent unnecessary operation of the acceleration sensor without increasing the operating force at the time of release.

When the locking means is moved to the unlocked position, the engaging portion of the stopper member moves from the movement locus of the inertial mass body in a direction different from the movement locus to the retracted position, so that the acceleration sensor operates. It will be possible.

[0011]

1 shows a mechanical ignition type acceleration sensor 10 to which a safety device for an acceleration sensor according to an embodiment of the present invention is applied.
It will be described with reference to FIG.

As shown in FIG. 4, 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 has a substantially cylindrical shape and is slidably arranged in a guide groove 32 formed in the body block 18. Therefore, the ignition pin 30 is movable along the axis P1 direction of the acceleration sensor 10.

As shown in FIG. 1, the ignition pin 30 includes
On the side of the body block 18 corresponding to the bottom wall 22, a pointed portion 34 is formed so as to project. The pointed portion 34 extends from the above-described through hole 26 formed in the bottom wall 22 to the outside when the ignition pin 30 moves to the side of the bottom wall 22 of the body block 18 (the state of the imaginary line in FIG. 1). Project.

On the other hand, the ignition pin 30 is provided 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 is arranged between the holder 36 and the bottom of the recess 30A for urging the ignition pin 30 in the direction of collision with the detonator 90 serving as an ignition charge, and the ignition pin 30 is constantly attached to the bottom wall 22. It urges in the direction of (through hole 26) (direction of arrow F). The ignition powder is not limited to the detonator 90.

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 cylindrical shape,
It is movably held in the case 41 and inertially moves in the direction of arrow B from the original position (the position indicated by the solid line in FIG. 1) 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 is held by 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 fixed. 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. 1 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 (upper side in FIG. 1), and a trigger is provided at the tip 42B. The upper end 50A of the lever 50 is rotatably engaged.

As shown in FIG. 2, 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. 1, a bearing portion 50D is formed on the lower surface of the lower portion 50C of the trigger lever 50, and a 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 in the counterclockwise direction 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. 2, 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. 1, in the ignition pin 30 urged by the firing spring 38 with the engagement claw 56 engaged with the engagement recess 54, the tip 34 of the ignition pin 30 is removed from the through hole 26. It is held at a separated position (position indicated by a solid line in FIG. 1). 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. 3, a concave portion 40A having a rectangular cross section along the axial direction of the inertial mass body 40 is provided on the outer peripheral portion of the end portion of the inertial mass body 40 on the lid block 20 side (left side in FIG. 3).
Are formed. A plate spring 72 as a stopper member is provided at a portion facing the recess 40A. One end of the leaf spring 72 is a fixed portion 72A, and the fixed portion 72A is fixed to the inner peripheral portion of the body block 18 by a screw 74. The other end of the leaf spring 72 is bent so as to be orthogonal to the axial direction of the inertial mass body 40 to form an engaging portion 72B. The fixing portion 72A and the engaging portion 72B of the leaf spring 72 are connected to each other. The middle part is
Abutting portion 72 inclined with respect to the axial direction of the inertial mass body 40
It is C.

A shaft 76 as a locking means is provided at a portion of the leaf spring 72 facing the abutting portion 72C, and an end portion of the shaft 76 on the leaf spring 72 side has a conical pointed portion 76A. Has been done. The shaft 76 penetrates the through hole 78 of the lid block 20 and is movable in the movement trajectory direction of the inertial mass body 40 (arrow C direction and arrow B direction). A stopper pin 77 is fixed to the center of the shaft 76. A compression coil spring 79 is inserted into the stopper pin 77 and the lid block 20, and the shaft 76 is attached to the compression coil spring 7.
It is urged by 9 in the direction of the leaf spring 72 (direction of arrow C).

Therefore, the shaft 76 is locked by the urging force of the compression coil spring 79 (indicated by the solid line).
And in this locked position, the cusp 76 of the shaft 76
A presses the contact portion 72C of the leaf spring 72. As a result, the leaf spring 72 is elastically deformed and rocks in the clockwise direction (direction of arrow E) to reach the entry position shown by the solid line in FIG. That is, the engaging portion 72B enters on the movement locus of the inertial mass body 40 from a direction different from the movement locus, reaches the entry position, engages the inertial mass body 40, and moves the inertial mass body 40 in the direction of arrow B. Block.

A handle 80 is integrally provided at the other end of the shaft 76, and a convex portion 82 is formed on the outer surface of the lid block 20 in the vicinity of the through hole 78.
Therefore, the handle 80 is pulled out in the direction of the arrow B against the biasing force of the compression coil spring 79 and rotated about the axis to engage the handle 80 with the convex portion 82 as shown by the imaginary line in FIG. Can be set to the unlocked position. As a result, the leaf spring 72 is restored and swings in the counterclockwise direction (direction of arrow G) to the retracted position shown by the imaginary line. That is, the engaging portion 72B moves from the movement locus of the inertial mass body 40 in a direction different from the movement locus, and the retracted position (position of the imaginary line).
Becomes

The acceleration sensor 10 having the above-described structure is inserted into the cylindrical case 87, and is attached 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). The trigger claw portion 56 of the trigger lever 50 is located away from the through hole 26).
The engagement pin 54 is engaged with the ignition pin 30 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, the shaft 76 is locked by the urging force of the compression coil spring 79 (the position indicated by the solid line).
And the apex 76A of the shaft 76 presses the abutting portion 72C of the leaf spring 72. As a result, the leaf spring 72 elastically deforms and swings in the direction of arrow E to reach the entry position shown by the solid line. That is, the engaging portion 72B of the leaf spring 72 is
It enters on a movement locus of 0 from a direction different from the movement locus, engages with the inertial mass body 40, and blocks movement of the inertial mass body 40 in the direction of arrow B.

In this state, when an impact force is applied to the inertial mass body 40 in the direction of arrow B and the inertial mass body 40 tries to move, the direction of this movement force (direction of arrow B) is the retreating direction of the leaf spring 72. (Direction of arrow G), that is, a direction different from the restoration direction. For this reason, only a part of this force acts in the releasing direction of the shaft 76 that is movable in the movement trajectory direction of the inertial mass body 40 (direction of arrow B). That is,
The removal force of the shaft 76 is extremely small. Therefore, since the biasing force of the compression coil spring 79 can be reduced, unnecessary operation of the acceleration sensor can be prevented without increasing the operating force at the time of release.

Here, the handle 80 is pulled out in the direction of the arrow B against the urging force of the compression coil spring 79 and rotated about the axis, so that the handle 80 has a convex portion as shown by an imaginary line in FIG. When it is engaged with 82 and is in the unlocked position, the leaf spring 72 is restored and swings in the direction of arrow G to the retracted position shown by the imaginary line. That is, the engaging portion 72B is the inertial mass body 40.
The vehicle moves from the movement locus in a direction different from the movement locus to the retreat position. As a result, the mechanical ignition type acceleration sensor 10 is set in an operable state.

When a large acceleration acts on the mechanical ignition type acceleration sensor 10 in such a state, the inertial mass body 40 inertially moves in the direction of arrow B. 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 end portion 42B of the arm 42 is swung in the arrow A direction.

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 to release the holding of the ignition pin 30. 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.

Although the leaf spring 72 is used as the stopper member in this embodiment, the stopper member is not limited to the leaf spring 72. In addition, in this embodiment, the end portion of the shaft 76 on the side of the leaf spring 72 is formed by a conical pointed portion 76A.
However, the shape of the end portion of the shaft 76 on the leaf spring 72 side is not limited to the conical shape. In addition, in the present embodiment, an example in which the safety device for an acceleration sensor of the present invention is applied to a mechanical ignition type acceleration sensor has been described, but the safety device for an acceleration sensor of the present invention uses the inertial mass body to energize the contacts. The present invention can also be applied to an electric ignition type acceleration sensor for igniting

[0039]

As described above, the safety device for an acceleration sensor according to the present invention locks the inertial mass body that inertially moves from the original position when an acceleration of a predetermined value or more is applied, and the movement direction of the inertial mass body. Locking means movable to a position and an unlock position, a fixing part fixed to the acceleration sensor main body side, an engaging part engaging with the inertial mass body, and an engaging part located on the movement track of the locking means. When the lock means moves to the lock position, the contact portion is pressed by the lock means, and the engagement portion enters on the movement locus of the inertial mass body from a direction different from the movement locus and engages with the inertial mass body. When the locking means is moved to the unlock position and the engaging portion is moved to the retracted position from the movement locus of the inertial mass body in a direction different from the movement locus, it is configured to release. The invention has an advantage of preventing unnecessary operation without increasing the urging force of.

[Brief description of drawings]

FIG. 1 is a side sectional view showing an acceleration sensor to which a safety device for an acceleration sensor according to an embodiment of the present invention is applied.

FIG. 2 is a sectional view taken along line 2-2 of FIG.

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

FIG. 4 is an exploded perspective view showing an acceleration sensor to which a safety device for an acceleration sensor according to an embodiment of the present invention is applied.

FIG. 5 is a side sectional view showing a safety device for an acceleration sensor according to a conventional example.

[Explanation of symbols]

 10 Mechanical ignition type acceleration sensor 40 Inertial mass body 44 Bias spring 72 Leaf spring (stopper member) 72A Fixed part 72B Engagement part 72C Abutment part 76 Shaft (locking means) 79 Compression coil spring

Claims (1)

[Claims] 1. An inertial mass body that inertially moves from an original position when an acceleration of a predetermined value or more is applied, and a locking means that is movable to a lock position and an unlock position along a movement locus direction of the inertial mass body. The lock means includes a fixed portion fixed to the acceleration sensor main body side, an engagement portion that engages with the inertial mass body, and an abutting portion that is located on a movement locus of the lock means. The contact portion is pressed by the locking means, the engaging portion enters on the movement locus of the inertial mass body from a direction different from the movement locus, engages with the inertial mass body, and the locking means. And a stopper member in which the engaging portion moves from a movement locus of the inertial mass body in a direction different from the movement locus to an evacuation position when is moved to an unlock position. Safety device.