JPH0740044B2 - Vehicle acceleration detection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial field of application> The present invention minimizes the forward movement of an occupant in the event of a collision accident, such as a device for automatically tightening seat belt looseness or an airbag device. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle acceleration detection device for an occupant protection device.

<Prior Art> A seat belt for restraining movement of an occupant is provided in a seat of an automobile in order to prevent the occupant from being thrown forward in a collision accident or the like. These seat belts do not restrain the normal driving operation, and it is preferable that the seat belt is tensioned only when a deceleration of a predetermined value or more is applied, and therefore, for example, in Japanese Utility Model Publication No. 62-161069 disclosed by the applicant. In this regard, there has been proposed a preloader device that detects the impact at the time of collision, ignites a propellant, etc., and uses the energy at this time to tension the seat belt. Further, U.S. Pat. No. 4,148,503 discloses a device in which an airbag that rapidly inflates at the time of a collision is incorporated in a steering wheel to reduce the impact on an occupant.

<Problems to be Solved by the Invention> On the other hand, as a collision detection device for operating those occupant protection devices, one utilizing the operation of a weight due to inertial force is often used (US Pat. No. 4,580,810). (See No.), they must operate reliably at the set deceleration, and must not malfunction during normal operation. Further, these collision detection devices require extremely high reliability because it is difficult to perform a normal operation test due to the peculiarities of the usage situation.

In view of such circumstances, a main object of the present invention is to provide an acceleration detecting device for a vehicle which is improved so as to obtain higher operation reliability.

<Means for Solving Problems> According to the present invention, such an object is to discharge the energy stored in advance in the energy storage means when a predetermined acceleration or deceleration acts on the vehicle. An acceleration detecting device for a vehicle, which is elastically biased in a non-operating direction and pivotally supported so as to be swingable independently of each other.
Two sensor weights, a trigger arm supported to define the activated and deactivated states of the energy storage means,
Spring means for elastically urging the trigger arm in a direction to activate the energy storage means, and the two sensor weights and the trigger arm are engaged with each other in order to keep the energy storage means in the inactive state. It is achieved by providing an acceleration detection device for a vehicle, characterized in that it has at least two types of engagement means.

<Operation> In this way, if at least two systems of sensor weights for holding the trigger arm in the non-actuated position are provided, and the types of the engaging portions of the trigger arm and the sensor weight are different from each other, malfunctions will occur. It is possible to effectively reduce the probability of the operation, and to further enhance the reliability of its operation.

<Examples> Hereinafter, preferred examples of the present invention will be described in detail with reference to the accompanying drawings.

1 and 2 show the acceleration sensor 1 in detail.

A pair of pendulums 3a and 3b as sensor weights are suspended on both sides of the sensor body 2 of the acceleration sensor 1 so as to be swingable about the upper end of the pendulums 3a and 3b. Both of these pendulums 3a and 3b have a U-shaped cross section with the upper side open.
The inner and outer layers are combined, and they are respectively supported by supporting shafts 4a and 4b arranged in parallel with each other, so that they can swing independently without interfering with each other's motion. ing.

In the middle part sandwiched by the two pendulums 3a and 3b of the sensor body 2, the two end faces 2a and 2b of the sensor body 2 are communicated with each other along the tangential direction to the swing locus of the two pendulums 3a and 3b.
A guide hole 4 having a cylindrical shape is formed.

The guide hole 4 is provided with a spring receiver 5 at an opening on the side of one end face 2a, and a firing pin 6 for igniting a detonator such as propellant as energy storage means is inserted therein. The firing pin 6 includes a tip 6a and a bottomed cylindrical plunger 6b that slides into the guide hole 4, and
The other end face of the guide hole 4 is formed by a small-diameter first coil spring 7 contracted in 6b and a large-diameter second coil spring 8 contracted between the end of the plunger 6b and the spring receiver 5. Repulsion is constantly urged toward the opening on the 2b side.

As also shown in FIG. 3, a trigger arm 9 is pivotally supported between the opposing surfaces of the sensor body 2 and the inner pendulum 3b so as to be swingable in a seesaw manner. The trigger arm 9 has a substantially crank shape in a side view (FIG. 1) and a substantially U shape in a front view (FIG. 2). The upper open end 9a of the trigger arm 9 is inserted into the guide hole 4 to allow the firing needle 6 to move. The open end 9a is adapted to engage with the engaging portion 6c formed on the plunger 6b.

The trigger arm 9 is pivotally supported at a bent portion near the open end 9a, but a support shaft 10 for supporting the trigger arm 9 is provided.
After penetrating both side surfaces of both pendulums 3a and 3b, is cut vertically in the sensor body 2 and projects into the guide groove 11. As a result, the support shaft 10 can be displaced along the guide groove 11 only in the vertical direction.

Through holes 12a, 12b are formed in the side portions of both pendulums 3a, 3b to insert both ends of the support shaft 10, respectively. These through holes 12
Through hole 12a opened in the outer pendulum 3a of a and 12b
Is provided with a locking portion 13 so as to define the vertical position of the support shaft 10, and from the locking portion 13 to the rear and back.
It is expanded downward immediately after 13 and the pendulum 3a can be displaced forward by releasing the locked state with the support shaft 10,
The support shaft 10 which is disengaged from the locking portion 13 can be displaced downward (FIG. 6).

On the other hand, the through hole 12b formed in the inner pendulum 3b is expanded rearward and downward with reference to the position of the support shaft 10 when it is locked in the locking portion 13 of the outer pendulum 3a. , Spindle
The inner pendulum 3b can be displaced forward without being hindered by 10, and the downward displacement of the support shaft 10 is not hindered (FIG. 8).

As shown in FIG. 4, a U-shaped end formed at the rear end side of the trigger arm 9 is provided at the rear edge of the bottom side of the inner pendulum 3b.
A projecting piece 14 is provided so as to engage with the bottom of the 9b. Then, the trigger arm 9 is engaged with the firing pin 6 in a state in which the support shaft 10 is engaged with the engaging portion 13 of the outer pendulum 3a and the U-shaped end 9b is engaged with the protrusion 14 of the inner pendulum 3b. By engaging the open end 9a with the joint 6c, the firing pin 6 is held stationary against the biasing force of the first and second coil springs 7 and 8.

Protrusions 15a and 15b are formed at the front end portions on the bottom side of both pendulums 3a and 3b, respectively. Bias springs 16a and 16b are respectively contracted inside the sensor body 2 facing the protrusions 15a and 15b in a direction parallel to the axis of the guide hole 4. These bias springs 16a and 16b are protrusions of both pendulums 3a and 3b via guide caps 17a and 17b, respectively.
It is in contact with 15a ・ 15b, which allows both pendulums 3a ・ 3b
Is always urged toward the rear. In this way, the rear protrusion 14 of the inner pendulum 3b and the U of the trigger arm 9 are
The engagement with the character-shaped end 9b and the engagement between the engaging portion 13 of the outer pendulum 3a and the end of the support shaft 10 of the trigger arm 9 are always maintained.

Next, the operation of the device of the present invention shown in the above embodiment will be described with reference to FIGS.

In a normal traveling state, the moment of inertia acting on both pendulums 3a and 3b and the biasing force of the bias springs 16a and 16b are set to suspend, as shown in FIGS. 5 and 7. The position of the support shaft 10 of the trigger arm 9 is regulated by the guide groove 11 of the sensor body 2 and the locking portion 13 of the outer pendulum 3a, and at the same time, the U-shaped end 9b causes the rear projecting piece 14 of the inner pendulum 3b. Since the rotation of the trigger arm 9 is blocked by engaging with, the firing pin 6 is blocked from its movement at the open end 9a of the trigger arm 9.

When a vehicle collides and a deceleration of a predetermined value or more acts in the traveling direction, the inertial force overcomes the biasing force of the bias springs 16a and 16b and swings the lower ends of the two pendulums forward. 3a and 3b tilt. This allows the inner pendulum
The U-shaped end 9a of the trigger arm 9 is disengaged from the protruding piece 14 of 3b.
Then, the restraint force acting on the firing pin 6 is released, and
By the elastic force given from the second both coil springs 7 and 8,
The open end 9a of the trigger arm 9 is pushed away and the firing pin 6 is ejected toward the detonator F (FIG. 8).

Further, when the support shaft 10 of the trigger arm 9 is disengaged from the locking portion 13 of the outer pendulum 3a, the open end 9a of the trigger arm 9 is moved to the support shaft 10a.
With this, the restraining force acting on the firing pin 6 is released in the same manner as above, and the first and second coil springs 7
By the elastic force given from 8, the open end 9a of the trigger arm 9 is pushed away and the firing pin 6 is ejected toward the detonator F (FIG. 6).

When the tip 6a of the firing pin 6 hits the detonator F, the propellant B is ignited, and the explosion pressure at this time drives a seat belt pro-leader device (not shown) or the like.

In such a collision detection device, extremely high operational reliability is required. Therefore, in the present invention, two systems of pendulums 3a and 3b as sensor weights are provided.
The engagement types of 3a and 3b and the trigger arm 9 are different from each other. By doing this, for example,
When the locking portion 13 of the outer pendulum 3a and the support shaft 10 of the trigger arm 9 are stuck, or when the protrusion 14 of the inner pendulum 13b and the U-shaped end 9b of the trigger arm 9 are stuck, Even if one of the engaging parts of the pendulum is defective, the firing pin 6 can be ejected only by the operation of the other pendulum to reduce the probability of malfunction of the vehicle collision character. I am trying to make it.

In the above description of the operation, the individual pendulums are explained individually, but it goes without saying that the firing pin 6 is ejected without any change even when both the pendulums 3a and 3b operate simultaneously.

By the way, the engagement force between the trigger arm 9 and the pendulums 3a and 3b is mainly affected by the contact surface contact between the two. Therefore, in order to reduce the manufacturing variation of this type of acceleration detection device, it is preferable that the dimensional accuracy of the contact portion of the above-mentioned engaging portion is increased as much as possible. Therefore, in the above-described embodiment, considering the variation of the rounded portion which is produced when it is manufactured by, for example, punching, as shown in FIG. 4, the front side corner portion of the U-shaped end 9b of the trigger arm 9 is taken. A notch N is provided in the front end of the pendulum 3b so that the rounded portions of the U-shaped end 9b do not interfere with each other when the front edge of the U-shaped end 9b is brought into contact with the rear end surface of the bottom of the pendulum 3b. As a result, the contact area size (Fig. 1)
The accuracy of l) can be easily ensured.

Further, the contact portion C of the open end 9a of the trigger arm 9 with respect to the engaging portion 6c of the firing pin 6 is also formed with an inclined surface so that the firing pin 6 can be smoothly released.

On the other hand, in order to maintain a stable sensitivity characteristic, it is necessary for the engaging portions of the pendulums 3a and 3b and the trigger arm 9 to surely return even when the trigger arm 9 has an inertia that is not released. is there. In the above embodiment, considering this point,
The engaging portions between the pendulums 3a and 3b and the trigger arm 9 are arranged directly below the support shafts 4a and 4b of the pendulums 3a and 3b, respectively. By doing so, even when the pendulums 3a and 3b are slightly displaced, the engaging portion is not twisted, and the return to the source position can be smoothly performed.

<Effects of the Invention> As described above, according to the present invention, it is possible to effectively eliminate the factors that cause the acceleration detection device to malfunction.
A great effect can be achieved in improving the reliability of the acceleration detecting device.

[Brief description of drawings]

FIG. 1 is a side view showing an embodiment of the present invention with a part cut away. FIG. 2 is a front view of the same. 3 and 4 are transparent perspective views showing only a main part. 5 to 8 are explanatory views showing the operating state of the present embodiment. 1 ... Acceleration sensor, 2 ... Sensor body 2a / 2b ... End face, 3a / 3b ... Pendulum 4 ... Guide hole, 4a / 4b ... Spindle 5 ... Spring bearing, 6 ... Hitting needle 6a. Tip, 6b ... Plunger 6c ... Engagement part, 7 ... First coil spring 8 ... Second coil spring, 9 ... Trigger arm 9a ... Open end, 9b ... U-shaped end 10 ... Support Shaft, 11 …… Guide groove 12a ・ 12b …… Through hole, 13 …… Locking part 14 …… Projection piece, 15a ・ 15b …… Protrusion 16a ・ 16b …… Bias spring 17a ・ 17b …… Guide cap

Claims (3)

[Claims] 1. An acceleration detecting device for a vehicle, wherein energy stored in advance in an energy storage means is released when a predetermined acceleration or deceleration acts on the vehicle. And at least two sensor weights pivotally supported independently of each other, a trigger arm supported to determine the activated and deactivated states of the energy storage means, and the energy storage means. Spring means for elastically urging the trigger arm in a direction to cause the trigger arm and the energy storage means to be kept inactive.
An acceleration detecting device for a vehicle, comprising one sensor weight and at least two types of engaging means for engaging the trigger arm with each other. 2. The trigger arm is rotatably rotatably supported, one of the types of the engaging means restricts the rotation of the trigger arm, and the other one of the types of engagement means displaces the rotation shaft. The vehicle acceleration detection device according to claim 1, wherein the acceleration detection device is restricted. 3. The rotation axis of the trigger arm is defined in the front-rear position, but is displaceable in the vertical direction, according to claim 1 and claim 2. Vehicle acceleration detection device.