JPH0659170U - Acceleration sensor and ignition plate - Google Patents

Abstract

(57) [Abstract] [Purpose] To reduce the manufacturing cost of an acceleration sensor while enabling downsizing. [Structure] The ignition plate 38 is formed by pressing a plate material.
The cross section is L-shaped, and the tip side of the ignition plate 38 is further crushed by press working or the like to form a protrusion 94. A biasing portion 71 is cut and raised at an intermediate portion of one side of the ignition plate 38, and a coil spring 74 is interposed between the biasing portion 71 and the lid 51. An engaging portion 72, which is formed by cutting out a part of the ignition plate 38, is formed at an intermediate portion of the other side of the ignition plate 38 so as to engage with the rotating body 76. That is, since the ignition plate 38 is formed of a plate material, it is not necessary to position the protrusion 94, the urging portion 71, and the engaging portion 72 on the same axis, and the degree of freedom of arrangement of the members in the acceleration sensor 36 is reduced. Will increase.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an acceleration sensor and an ignition plate that activate an occupant protection device when the vehicle is suddenly decelerated by a predetermined amount of inertial movement of an inertial body due to the action of acceleration.

[0002]

[Prior art]

 BACKGROUND ART An airbag device is known as a vehicle occupant protection device.

The airbag device is designed to protect the occupant by bulging the bag when the vehicle suddenly decelerates, and an acceleration sensor is used to activate the airbag device when the vehicle suddenly decelerates.

As an example of a conventional acceleration sensor, those shown in FIGS. 9 and 10 are known. This acceleration sensor has a structure in which a ball 152 as an inertial body is inserted into a cylinder 190 installed in a housing 150, and when the ball 152 receives an acceleration generated when the vehicle suddenly decelerates, it is indicated by an arrow FR. Inertial movement is possible in front of the vehicle.

Further, a columnar rotating body 176 is provided in the housing 150. The rotating body 176 has a trigger portion 180 that is cut out in a semicylindrical shape at an intermediate portion, a support shaft 166 that is formed to project at both end portions thereof is supported on the housing 150 side, and the inertia of the ball 152 is The center of rotation is the direction orthogonal to the direction of movement, and the body is rotatable.

An intermediate portion of the lever 164 is fixed to one end of the rotating body 176. One end of the lever 164 extends to the front surface in the inertial movement direction of the ball 152, and the other end of the lever 164 is pressed by a bias spring 168 via a pin 156.

Further, an ignition pin 138, which is constantly urged toward the starting position where the detonator 132 is ignited by the ignition spring 174, is movably installed between the starting position and the non-starting position. A disc-shaped engaging collar 172 is formed at an intermediate portion in the longitudinal direction of the ignition pin 138, and the engaging collar 172 and the outer peripheral surface of the rotating body 176 are associated with the rotation of the rotating body 176. Can be engaged and disengaged.

Therefore, in a normal state, the engagement flange 172 and the outer peripheral surface of the rotating body 176 are engaged with each other to prevent the ignition pin 138 from moving to the starting position. By inertially moving against 168 and pressing one end of the lever 164, the rotating body 176 is rotated, and the trigger portion 180 faces the engaging collar 172 and the engagement is released.

With this release, the ignition pin 138 moves toward the detonator 132 based on the urging force of the ignition spring 174 and collides with it, and the detonator 132 is ignited. By the ignition of the detonator 132, the gas generating substance burns to generate gas, and the generated gas is supplied into the bag body and the bag body swells.

[0010]

[Problems to be solved by the device]

 In the acceleration sensor having the above structure, as shown in FIG. 10, the outer diameter of the engaging collar 172 on the same axis as the ignition pin 138 and the ignition spring 174 causes the engaging collar 172 to engage with the rotating body 176. Since the cylinder 190 that guides the inertial movement of the ball 152 has a large outer diameter, the distance S2 between the center of the engagement flange 172 and the center of the ignition pin 138 that collides with the detonator 132 is reduced. As the size increases, it is difficult to install the ignition pin 138, the engaging collar 172, and the ignition spring 174 at free positions in the acceleration sensor.

As a result, the miniaturization of the acceleration sensor is accompanied by a demand for assembling the airbag device in which it is not necessary to position the ignition pin 138 at the center of the acceleration sensor so as to align the rotational direction of the acceleration sensor. It was a factor to prevent. Even if the ignition pin 138 is not located at the center of the acceleration sensor, the distance S2 is large, which hinders downsizing of the acceleration sensor.

On the other hand, since it is necessary to provide the engaging collar 172 in the intermediate portion of the ignition pin 138, when manufacturing the ignition pin 138, a material having the same thickness as the outer diameter of the engaging collar 172 is cut by a lathe or the like. It was Therefore, there is a drawback that the manufacturing cost of the ignition pin 138 and the engaging collar 172 is excessive.

In view of the above facts, an object of the present invention is to provide an acceleration sensor and an ignition plate that can be downsized while reducing the manufacturing cost.

[0014]

[Means for Solving the Problems]

 The acceleration sensor according to claim 1 is an ignition sensor in which an inertial member having an inertial body that inertially moves due to the action of acceleration and a projection formed on a tip side of a plate material are opposed to a detonator for activating an occupant protection device. A plate, an urging portion formed on the ignition plate and contacting an elastic member for urging the ignition plate toward the detonator side to receive an urging force from the elastic member, and the urging member formed on the ignition plate And an engaging portion which is engaged with a body member to prevent the ignition plate from moving toward the detonator side and which is disengaged by the inertial movement of the inertial body when the vehicle suddenly decelerates. .

An ignition plate according to a second aspect is an ignition plate used for an acceleration sensor that activates an occupant protection device by detecting sudden vehicle deceleration due to inertial movement of an inertial body, and includes a body formed of a plate material, and An urging portion formed on the main body and contacting an elastic member for urging the main body to the detonator side to receive an urging force from the elastic material, and an occupant protection device protruding in a direction along a plate surface of the main body. It is characterized in that a projection facing the detonator for starting is provided.

An acceleration sensor according to a third aspect of the invention is characterized in that a plurality of projecting portions facing a plurality of detonators for activating an occupant protection device are provided at a tip end portion of an ignition plate.

An acceleration sensor according to a fourth aspect of the present invention is characterized in that a longitudinal direction of a portion of the engaging portion that engages with the inertial member is along the width direction of the ignition plate.

[0018]

[Action]

 The operation of the acceleration sensor according to claim 1 will be described below.

At normal times, the engagement portion of the ignition plate engages with the inertial member to prevent the ignition plate from moving toward the detonator side.

When the vehicle is rapidly decelerated, the acceleration acts on the inertial body to cause inertial movement of the inertial body, and the engagement of the inertial body member with the engaging portion is released. As a result, the contact of the elastic member with the biasing part causes the ignition plate that is biased toward the detonator side to move to the detonator side, and the projection of the ignition plate collides with the detonator, causing ignition to the detonator. Activates the passenger protection device.

Since the ignition plate is made of a plate material, it is necessary to position the protrusion that strikes the detonator, the urging portion that abuts the elastic material, and the engagement portion that engages the inertial member on the same axis. And the disk-shaped engaging collar is not necessary. Therefore, the degree of freedom in arranging the members in the acceleration sensor is increased, and the acceleration sensor can be further downsized.

Further, it is not necessary to form the disc-shaped engaging collar, and the manufacturing cost can be reduced.

The operation of the ignition plate according to claim 2 will be described below. When the vehicle suddenly decelerates, the acceleration acts on the inertial body and the inertial body moves inertially, and the acceleration sensor detects sudden vehicle deceleration. At this time, the body of the ignition plate, which is biased toward the detonator side, moves toward the detonator side due to the contact of the elastic material with the energized portion, and the projection of the ignition plate collides with the detonator, causing ignition to the detonator. Activates the passenger protection device.

Further, since the main body of the ignition plate is formed of the plate material, it is not necessary to position the projecting portion that strikes the detonator and the urging portion that contacts the elastic material on the same axis.

Further, since the body of the ignition plate is formed of a plate material, it is not necessary to form a disc-shaped engaging collar as in the first aspect, and the manufacturing cost can be reduced.

The operation of the acceleration sensor according to claim 3 will be described below. In addition to the operation according to claim 1, since the plurality of projecting portions facing the plurality of detonators are provided at the tip of the ignition plate, it is not necessary to provide the ignition plates by the number corresponding to each of the plurality of detonators. By reducing the number of points, the structure can be simplified and the acceleration sensor can be easily assembled.

The operation of the acceleration sensor according to the fourth aspect will be described below. In addition to the action according to claim 1, since the longitudinal direction of the portion of the engaging portion that engages with the inertial member is along the plate width direction of the ignition plate, the ignition plate is attached to the engaging portion. The force of the elastic material that is urged is dispersed, and the deformation of the engaging portion is prevented even when the thickness of the ignition plate is thin.

[0028]

【Example】

 An acceleration sensor according to a first embodiment of the present invention is shown in FIGS. 1 to 4, and the present embodiment will be described with reference to these drawings.

In FIG. 4 (arrow FR indicates the front of the vehicle), an airbag device 10 is shown. The airbag device 10 includes an inflator 12, a cover 14, and an airbag bag body 16 (hereinafter, simply referred to as a bag body 16), and is attached to a base plate 22 supported by a hub 20 of the steering wheel 18.

The inflator 12 has a cylindrical shape that is coaxial with the rotation axis of the steering wheel 18, and one side along the rotation axis of the inflator 12 penetrates the base plate 22 and projects toward the occupant. It is fixed through 24.

The bag body 16 is arranged in a folded state on the occupant side of the base plate 22, and the peripheral edge of the opening portion 26 is fixed to the base plate 22 by a mounting ring 28. The one side of the inflator 12 is inserted into the bag body 16, and a gas hole 40 of the inflator 12 is opened facing the inside of the bag body 16.

The cover 14 is formed in a bowl shape, and an opening edge thereof is fixed to the base plate 22 so as to store the bag body 16 between the cover 14 and the base plate 22. A thin portion 29 is formed on the bottom wall of the cover 14 facing the occupant, and when the bag body 16 is inflated, the thin portion 29 is broken and the cover 14 is opened from the center portion into a pair of doors and deployed. It is possible.

In addition, the inflator 12 houses the enhancer 30, the detonator 32, the gas generating substance 34, and the acceleration sensor 36. When the vehicle suddenly decelerates, the ignition plate 38 on the acceleration sensor 36 side collides with the detonator 32 and the detonator 32. Is ignited, the gas generating substance 34 is ignited based on the ignition, and gas is generated, and the gas is supplied into the bag body 16 through the gas holes 40.

Here, the acceleration sensor 36 will be described in detail. As shown in FIGS. 1 to 3, a cylindrical cylinder 90 is fitted and fixed inside the housing 50 and the lid 51 that form the outer frame of the acceleration sensor 36. A ball 52, which is an inertial body having a predetermined mass, is inserted into the cylinder 90 so as to be slidable along the axial direction of the cylinder 90. Further, the ball 52 abuts on the bottom surface 61 of the housing 50. The above rearward movement of the vehicle is blocked.

As described above, the ball 52 is movable in the cylinder 90 along the vehicle front-rear direction.

In the housing 50, the ignition plate 38, the lever 64, the rotating body 76, etc. are provided.

The igniter plate 38 is formed by pressing a plate material and bending the plate material, and its cross-sectional surface is L-shaped. The tip side of the igniter plate 38 is further crushed by the press work or cut by the shaving process. As a result, a sharp pyramid-shaped protrusion 94 is projected in the direction along the plate surface of the ignition plate 38. The ignition plate 38 is guided by the support surface 70 (see FIG. 1) in the housing 50 and is arranged such that the longitudinal direction, which is the moving direction, is parallel to the moving direction of the ball 52.

As a result, from the non-starting position where the projection 94 of the ignition plate 38 is located inside the housing 50, the projection 94 of the ignition plate 38 goes out of the housing 50 and collides with the detonator 34, so that the detonator 32 is The ignition plate 38 is movable to a starting position where it is ignited and the airbag apparatus 10 is started.

A biasing portion 71 is cut and raised from the ignition plate 38 at an intermediate portion of one side of the ignition plate 38, and a coil spring 74, which is an elastic material, is interposed between the biasing portion 71 and the lid 51. Is present. The coil spring 74 constantly urges the ignition plate 38 toward the starting position.

Further, as shown in FIG. 2, an engaging portion 72, which is formed by cutting out a part of the ignition plate 38, is formed at an intermediate portion of the other side of the ignition plate 38, and corresponds to the engaging portion 72. Then, a rotating body 76 having a cylindrical shape is provided, and the engaging portion 72 is normally engaged with the outer peripheral surface of the rotating body 76.

Further, the support shafts 66 formed so as to project from both ends of the rotating body 76 are supported by bearings (not shown) on the housing 50 side, and the center of rotation of the balls 52 along the direction orthogonal to the inertial movement direction. The rotating body 76 is rotatable around the line.

As shown in FIG. 1 to FIG. 3, the rotating body 76 is formed with a trigger portion 80 that is cut out in a semi-cylindrical shape at its intermediate portion, and as the rotating body 76 rotates, When the engaging portion 72 and the trigger portion 80 face each other, the engagement of the outer peripheral surface of the rotating body 76 with the engaging portion 72 is released.

A base end of a lever 64, which is long in a direction orthogonal to the inertial movement direction of the ball 52, is fixed to one end of the rotating body 76. The tip of the lever 64 extends to the front surface in the moving direction of the ball 52, and in FIG. 1, the upper side of the tip of the lever 64 abuts the front surface of the ball 52 in the moving direction, and The top of the pin 56, which is pressed by the coil spring 68 interposed between the cover 51 and the lid 51, abuts on the.

Therefore, the lever 64 is rotationally biased by the coil spring 68 so that the tip of the lever 64 always presses the ball 52 rearward of the vehicle. When the ball 52 inertially moves forward of the vehicle against the urging force of the coil spring 68, the lever 64 is rotated in the clockwise direction in FIG. 2, and the rotating body 76 integrated with the lever 64 is rotated. To be done. That is, the ball 52, the lever 64, and the rotating body 76 constitute an inertial body member.

As described above, normally, the ignition plate 38 is held in the non-actuated position (state of FIG. 2), but when the vehicle suddenly decelerates, the acceleration acts on the ball 52 and the ball 52 inertially moves by a predetermined amount. Along with this, the ball 52 rotates the lever 64, and the rotation of the lever 64 releases the engagement of the outer peripheral surface of the rotating body 76 with the engaging portion 72, and the movement of the ignition plate 38 to the starting position is permitted. It

Next, the operation of this embodiment will be described. In normal vehicle operation, the acceleration acting on the ball 52 is small, and in this case, the ball 52 cannot counter the biasing force of the coil spring 68, and the inertial movement of the ball 52 is restricted. Further, even if the ball 52 moves a little amount against the urging force of the coil spring 68, the inside of the air chamber 92 becomes a negative pressure, so that the ball 52 is returned to the original state at an acceleration of a predetermined value or less.

Therefore, even when the vehicle travels on a rough road or the like, the ball 52 does not reach a predetermined amount of inertial movement, and the engaging portion 72 of the ignition plate 38 remains engaged with the outer peripheral surface of the rotating body 76. Then, the ignition plate 38 is prevented from moving toward the detonator 32 side. Therefore, the ignition plate 38 is held in the non-activated position and the airbag device 10 is not activated.

On the other hand, when the vehicle suddenly decelerates to activate the airbag device 10, the engagement of the outer peripheral surface of the rotating body 76 with the engaging portion 72 is released, as described above. As a result, the ignition plate 38 urged toward the detonator 32 moves to the starting position, the projection 94 of the ignition plate 38 collides with the detonator 32, and the gas generating substance 34 is burned by the ignition of the detonator 32. Gas is generated. Further, the generated gas is supplied into the bag body 16 and the airbag device 10 is activated.

Since the ignition plate 38 is formed of a plate material, the protrusion 94 that strikes the detonator 32, the urging portion 71 that abuts the coil spring 74, and the engaging portion that engages with the outer peripheral surface of the rotating body 76. Not only is it unnecessary to position 72 on the same axis, but since there is no disc-shaped engaging collar 172 as in the prior art, the distance S1 between the center of the ball 52 and the protrusion 94 can be reduced. The size of the acceleration sensor can be made smaller than that of the conventional technology. As a result, the degree of freedom in arranging the members in the acceleration sensor is increased, and the acceleration sensor can be further downsized.

Further, since it is not necessary to form the disc-shaped engaging collar 172 as in the prior art, it is possible to reduce the manufacturing cost without performing cutting work with a lathe or the like.

Next, an ignition plate 38 of an acceleration sensor according to a second embodiment of the present invention is shown in FIG. 5, and this embodiment will be described based on this drawing.

As shown in FIG. 5, when a pair of detonators 32 are provided, a structure in which a pair of protrusions 94 are formed on the tip side of the ignition plate 38 corresponding to the pair of detonators 32 is adopted. To be done. Therefore, it is not necessary to provide the ignition plates 38 in the number corresponding to each of the plurality of detonators 32, and the structure can be simplified by reducing the number of parts and the acceleration sensor 36 can be easily assembled.

In this embodiment, the detonator 32 and the protrusion 94 are paired, but three or more protrusions 94 may be provided according to the number of the detonators 32.

Next, the ignition plate 38 of the acceleration sensor according to the third embodiment of the present invention is shown in FIGS. 6 and 7, and this embodiment will be described based on these drawings.

As shown in FIGS. 6 and 7, in this embodiment, one end of one side of the L-shaped ignition plate 38 is the engaging portion 96, and the longitudinal direction of this one side is the rotating body 76. It is parallel to the axial direction. Therefore, the longitudinal direction of the portion that engages with the outer peripheral surface of the rotating body 76 is along the plate width direction of the ignition plate 38.

Therefore, the contact area between the engaging portion 96 and the rotating body 76 can be widened, the force of the coil spring 74 for urging the ignition plate 38 is dispersed, and the ignition plate 38 is thin. Also, the deformation of the engaging portion 96 is prevented.

Next, an ignition plate 38 of an acceleration sensor according to a fourth embodiment of the present invention is shown in FIG. 8, and this embodiment will be described based on this drawing.

As shown in FIG. 8, in the present embodiment, the urging force of the coil spring 74 is received by the concave urging portion 102 of the ignition plate 38 which is flat and formed into a substantially U shape by press working or the like. The shoulder portion on the tip end side is the engagement portion 104. Then, the protrusion 106 is formed by cutting or the like to have a conical shape.

Therefore, according to the present embodiment, there is no need to perform processing for bending the ignition plate 38 into an L shape, and the manufacturing cost can be further reduced. Further, by forming the protrusion 106 by cutting, the dimension of the protrusion 106 can be made more accurate with a small cost.

The other configurations of the second embodiment, the third embodiment, and the fourth embodiment are the same as those of the first embodiment, and therefore, the same effects as the first embodiment can be obtained. .

Further, the present invention is not limited to the above embodiments, but various modifications can be made. For example, in each of the above embodiments, the occupant protection device is the airbag device 10. However, the occupant protection device is not limited to this. Of course, it can also be applied to start up the preloader for mounting on the.

[0062]

[Effect of device]

 The acceleration sensor according to the first aspect has an excellent effect that the size can be reduced while reducing the manufacturing cost. On the other hand, the ignition plate according to the second aspect has an excellent effect that the manufacturing cost of the ignition plate can be reduced. Further, according to the acceleration sensor of the third aspect, the structure can be simplified and the assembling can be facilitated by reducing the number of parts. Furthermore, according to the acceleration sensor of the fourth aspect, there is an excellent effect that the deformation of the engaging portion can be prevented even when the thickness of the ignition plate is thin.

[Brief description of drawings]

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

FIG. 2 is a cross-sectional view of the acceleration sensor according to the first embodiment of the present invention taken along the vehicle front-rear direction, which is taken along line 2A of FIG.
It is the figure which combined and showed the 2A-2 arrow line and the 2B-2B arrow line.

FIG. 3 is an exploded perspective view of an acceleration sensor according to a first embodiment of the present invention.

FIG. 4 is a cross-sectional view of an airbag device to which the acceleration sensor according to the first embodiment of the present invention is applied, taken along the vehicle longitudinal direction.

FIG. 5 is a perspective view showing an ignition plate and a detonator of an acceleration sensor according to a second embodiment of the present invention.

FIG. 6 is a side view showing a rotating body and an ignition plate of an acceleration sensor according to a third embodiment of the present invention.

FIG. 7 is a front view showing a rotating body and an ignition plate of an acceleration sensor according to a third embodiment of the present invention.

FIG. 8 is a perspective view showing an ignition plate of an acceleration sensor according to a fourth embodiment of the present invention.

FIG. 9 is a cross-sectional view of an acceleration sensor according to a conventional technique taken along the vehicle front-rear direction.

FIG. 10 is a cross-sectional view of an acceleration sensor according to a conventional technique.

[Explanation of symbols]

 10 Airbag Device (Passenger Protection Device) 32 Detonator 36 Acceleration Sensor 38 Ignition Plate (Main Body) 52 Ball (Inertial Member) 64 Lever (Inertial Member) 71 Energizing Part 72 Engaging Part 74 Coil Spring (Elastic Body) 76 Rotating body (inertial member) 94 Projection part 96 Engagement part 102 Energizing part 104 Engagement part 106 Projection part

Claims (4)

[Scope of utility model registration request] 1. An inertial member having an inertial body that inertially moves under the action of acceleration, an ignition plate formed of a plate material, and a projection formed on a tip side thereof facing a detonator for activating an occupant protection device, An urging portion formed on the ignition plate and abutting an elastic member for urging the ignition plate toward the detonator side to receive an urging force from the elastic member; and an inertial member formed on the ignition plate on the inertia member. An acceleration sensor, comprising: an engagement portion that is engaged to prevent the ignition plate from moving toward the detonator side and that is disengaged by inertial movement of the inertial body when the vehicle suddenly decelerates. 2. An ignition plate used for an acceleration sensor that detects sudden vehicle deceleration by the inertial movement of an inertial body and activates an occupant protection device, the main body being formed of a plate material, and the ignition body being formed on the main body and An urging portion that abuts the main body with an elastic member that urges the detonator side to receive an urging force from the elastic member, and a urging portion that projects in a direction along a plate surface of the main body and faces a detonator for activating an occupant protection device. An ignition plate, which is provided with a protrusion. 3. The acceleration sensor according to claim 1, wherein a plurality of projections respectively facing a plurality of detonators for activating the occupant protection device are provided at the tip of the ignition plate. 4. The acceleration sensor according to claim 1, wherein a longitudinal direction of a portion of the engaging portion which engages with the inertial member is along a width direction of the ignition plate.