JPH09306311A - Collision detecting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a stable collision detecting signal. SOLUTION: In a weight 4, a shaft 5 is arranged in a position eccentric to the center of gravity of weight, and when acceleration not less than a prescribed level acts in the A direction, the moment acts on the center of gravity of its weight, and it rotates in the (a) direction with the shaft 5 as the center against elastic force energized from leaf springs 2 and 3. A rotor 1 rotates according to rotation of the weight 4, and the leaf springs 2 and 3 respectively eleastically energized to its first cam 1a and second cam 1b are displaced while mutually narrowing an interval, and a contact point 2a and a contact point 3a contact with each other by a prescribed rotational quantity of the rotor 1, and a collision detecting signal is outputted to an external part through output terminals 6a, 6b, 8a and 8b. In the weight 4, rotation exceeding a prescribed quantity it regulated by coming into contact with a stopper 16 having a beam structure whose both ends are fixed. A clearance part 9 is formed between a cover 10 and the stopper 16, and at contact time, the stopper 16 functions as a damper by bending to the clearance part 9 side, and absorbs impact by rotation of the weight 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a collision detecting device for detecting a collision of a moving body by detecting acceleration of a predetermined value or more. This collision detection device, for example,
In a vehicle, an airbag device for protecting an occupant,
It is used in a device for determining the timing of activating the seat belt retractor.

[0002]

2. Description of the Related Art Conventionally, as a collision detecting device used in an air bag system of a vehicle, the rotor is rotated by an acceleration acting on the rotor with a center of gravity and a center of rotation being eccentric. There is known a device that detects a vehicle collision by closing the vehicle (Japanese Patent Laid-Open No. 2-168525). However, in this device, the contact point member and the spring member that urges in the direction against the acceleration at the time of collision to give a resistance force to the rotation of the rotor are configured separately, so that the number of parts increases and the machine There was a problem that there were many dynamic connections. Further, because of this, it is structurally difficult to secure a space between the contacts, and it is difficult to downsize the collision detection device. Therefore, the present applicant has developed a collision detection device capable of reducing the number of parts by providing a leaf spring with a contact function and a function of elastically urging the rotor, and further downsizing with a simpler configuration. (Japanese Patent Application No. 6-172138).

[0003]

In the collision detecting device having this simple structure, the rotation of the weight is restricted by bringing the rotatable weight into contact with the stopper provided on the cover. However, since the damper effect of this stopper is small, when the waveform width of the acceleration is small (high frequency) and the peak value is large, such as in a side collision of the vehicle,
There is a problem that the contact is turned on / off, that is, chattering occurs, and a stable collision detection signal cannot be obtained.

Therefore, in view of the above problems, an object of the present invention is to prevent chattering between contacts and to obtain a stable collision detection signal by adopting a structure in which a damper effect of a stopper is improved. Is.

[0005]

Means for Solving the Problems To solve the above-mentioned problems, the means described in claim 1 can be adopted.
According to this means, the weight is rotatably supported together with the rotor at a position eccentric to the center of gravity of the weight, and the greater the acceleration acting on the weight, the more the weight rotates and receives the acceleration of a predetermined value or more. When the rotation angle of the weight exceeds a predetermined value, the rotor rotates accordingly, and the state of the contact points of the pair of contact point members changes. That is, if the contact is a normally open contact, the contact is closed, and if the contact is a normally closed contact, the contact is opened. On the other hand, in order to regulate the rotation of the weight by a predetermined angle or more, a regulation means is provided in the rotation path of the weight. The restricting means is an elastic body that can be bent in the direction of the acting force by the acting force from the weight, and is provided with a space that can be bent in the bending direction. The weight comes into contact with the restricting means, and further rotation is restricted. When the weight comes into contact with the regulation means, the regulation means bends in the rotation direction of the weight, so that the regulation means absorbs the rotational energy of the weight and functions as a damper for rotation of the weight. The shock is absorbed. Therefore, chattering between the contacts of the contact member can be prevented, the holding time of the contact state formed by the rotation of the weight can be increased, and a stable collision detection signal with a wide pulse width can be obtained.

According to the second aspect of the present invention, the tip end portions of the pair of leaf springs forming the contact member come into contact with the cam formed on the rotor, and move in the direction opposite to the rotation direction due to the acceleration to be detected. When the rotor is elastically biased to give a rotational resistance force and its acceleration is equal to or larger than a predetermined value, the contact state is changed by the action of the cam of the rotor. This allows
Since the weight is elastically biased in the direction opposite to the rotation direction, the contact state is prevented from changing due to the vibration of the vehicle or the deceleration that acts during sudden braking, thus improving the reliability of the collision detection device. Can be improved.

According to the third aspect of the invention, the restricting means is formed in a beam structure in which both ends are fixed and can bend when abutting against the weight. As a result, at the time of contact with the weight,
Since the contact portion of the regulating means is bent, the impact due to the rotation of the weight can be absorbed, and an effect equivalent to that of the means according to claim 1 can be obtained.

According to the means described in claim 4, both ends of the restricting means are fixed to the protective members constituting the casing, and when the weight comes into contact with the restricting means, the space allowing the restricting means to bend is provided. It is provided between the regulation means and the protection member. As a result, when the weight contacts the regulating means, the contact portion of the regulating means bends in the rotation direction of the weight, so that the impact due to the rotation of the weight is absorbed.
It is possible to obtain the same effect as that of the means described in.

According to a fifth aspect of the present invention, the restricting means is made of an elastic material such as a resin material having elasticity, a rubber material, a coil spring, or a leaf spring. Accordingly, when the weight and the regulating means are in contact with each other, the contact portion of the regulating means can be effectively bent in the direction of the acting force, and the damper effect of the regulating means can be enhanced.

According to the means described in claim 6, the cam of the rotor is composed of the first cam and the second cam, and the pair of leaf springs are brought into contact with the first cam and the second cam, respectively. The rotor is elastically biased in the direction opposite to the rotating direction at the time of collision. The biasing force of this leaf spring provides a resistance force to the rotation of the weight. Then, when the rotor rotates, the distance between the contacts of the pair of leaf springs is narrowed by the action of the first cam and the second cam, and the contacts are closed. This allows
Since the distance between the contact points of the pair of leaf springs can be sufficiently secured, the reliability of the collision detection device can be further improved.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described below based on specific embodiments. FIG. 1 is a perspective view showing a configuration of a collision detection device 20 according to the present invention, and FIG. 2 is an assembly development view showing the assembly thereof. The collision detection device 20 includes a cover 10 (corresponding to a protection member) that constitutes a resin casing, a flat plate-shaped base 12, and a housing 13.
The base 1 is fixed to the housing 13 and the housing 13 is fixed to the cover 10 by press fitting.

The housing 13 has a base portion 132 and a pair of column portions 130a, 130b facing each other, and grooves 131a, 131b are formed at the tips of the column portions 130a, 130b.
Are formed respectively. And those grooves 131
Both ends of the shaft 5 are mechanically fixed by a and 131b. A weight 4 having an eccentric center of gravity and a center of gravity of weight is attached to the shaft 5 so as to be rotatable around the shaft 5.
The weight 4 is formed by machining a metal plate, and a circular hole 4a is provided through the hole 4 by a drilling process in order to adjust the weight and the position of the center of gravity. The rotor 1 is formed on the weight 4 by resin molding so as to share the shaft 4 with the weight 4, and as a result,
The rotor 1 is rotatable around a shaft 5 in synchronization with the weight 4. The rotor 1 includes a first cam 1a and a second cam 1b.
And

A leaf spring 2 and a leaf spring 3 are erected at a predetermined interval on the base 12, and the leaf springs 2 and 3 respectively have contacts 2a and 3a at their tips. Contact 2a
Is a plane, but the contact 3a is formed in a convex shape on the side of the contact 2a. The ends 2b and 3b of the leaf springs 2 and 3 are in contact with the cam surfaces of the first cam 1a and the second cam 1b, respectively, and are opposite to the direction in which the weight 4 and the rotor 1 are rotated by the action of acceleration. It is elastically biased. This allows
Rotation of the weight 4 and the rotor 1 is restricted by minute acceleration that occurs during sudden braking or while traveling on a road surface having large unevenness.

In the leaf spring 3, a slit 3c is formed in the lengthwise direction from the substantially center thereof to the end portion 3b, and the end portion 3b has two slits.
Are separated into two. By forming the slit 3c, the contact between the contact 2a and the contact 3a can be favorably performed. The leaf springs 2 and 3 are output terminals 8a and 8 protruding outward, respectively.
b, and is fixed to the base 12 in contact with the output terminals 6a and 6b. A sealant 11 (see FIG. 3), which will be described later, is provided below the base 12 to keep the collision detection device 20 airtight. The output terminals 6a, 6b and 8a, 8b project to the outside from the lower side of the sealant 11, and the terminals 6a, 6b
Through 6b, 8a, and 8b, the closed state of the contact 2a and the contact 3a at the time of collision can be detected as a collision detection signal.

In the path along which the weight 4 rotates, a prism-shaped stopper 16 (corresponding to a regulating means) is disposed with both ends thereof held by the cover 10. The stoppers 16 are made of a resin material having elasticity, such as EPDM (ethylene-propylene trimer), and are fixed to both ends of the cover 10 by press fitting. The portion of the weight 4 in the direction of the rotation path in which the cover 10 faces the stopper 16 is thinned, so that a gap (space) 9 is provided between the stopper 16 and the cover 10. The weight 4 comes into contact with the stopper 16 at the time of rotation, so that the weight 4 is restricted from rotating more than a predetermined amount.

Fixed terminals 14a and 14b and fixed terminals 15a and 15b (see FIG. 3) are fixed to the mounting surface 10a side of the cover 10 by resin insert molding. The collision detection device 20 is fixed to a circuit board (not shown) or the like by using the fixed terminals 14a, 14b, 15a, 15b.
The fixed terminals 14a and 14b and the fixed terminals 15a and 15b are
As insert metal fittings 14 and 15 to be described later, they are integrally formed by machining thin metal plates.

3 (a), 3 (b) and 3 (c) show a front view, a side view and a bottom view of the collision detection device 20, respectively. The direction A in the figure indicates the collision direction. The insert fittings 14 and 15 are fixed terminals 14a,
14b and fixed terminals 15a and 15b are provided on both sides of the mounting surface 10a so that they are arranged at the four corners of the mounting surface 10a. In each of the insert fittings 14 and 15, fixed terminals 14a and 14b and fixed terminals 15a and 15b
Bends 14c and 15c by bending at the end opposite to
Are formed at a predetermined angle (generally right angle in the figure).

A front view of the insert fittings 14 and 15 is shown in FIG. 9A, and a side view thereof is shown in FIG. 9B. As shown in FIG. 9, the insert fittings 14 and 15 have asymmetrically shaped portions 14 at the bases of the fixed terminals 14a and 15b arranged diagonally in order to prevent erroneous placement described later.
d and 15d are formed respectively. Also, FIG.
As shown in (c), the sealant 11 is arranged around the output terminals 6a, 6b and the output terminals 8a, 8b to ensure the airtightness inside the detection device 20.

Next, the operation of the collision detection device 20 will be described. FIGS. 4A and 4B are a front sectional view and a side sectional view, respectively, of the collision detection device 20 when the acceleration of a predetermined level or more does not act and the contacts 2a and 3a are in the off state. . In this state, the rotor 1 is elastically biased in the B direction in the drawing by the leaf springs 2 and 3, and the weight 4 integrated with the rotor 1 is biased in the B direction in the drawing with respect to the housing 13. ing.

5 (a) and 5 (b), acceleration of a predetermined level or more acts on the case 10 in the direction B in the figure, and thus in the weight 4 in the direction A, so that the contacts 2a and 3a are in the ON state. The front cross-sectional view and the side cross-sectional view of the collision detection device 20 at the time of are respectively shown. When an acceleration of a predetermined level or more acts on the weight 4 in the A direction, a moment acts on the weight center of gravity of the weight 4, and the weight 4 and the rotor 1 move against the shaft 5 against the elastic force urged by the leaf springs 2 and 3. It rotates in the direction of "a" in the figure. Then, when the weight 4 contacts the stopper 16, the rotation of the weight 4 and the rotor 1 is restricted.

At this time, as the rotor 1 rotates, the leaf springs 2 and 3, which were in contact with the first cam 1a and the second cam 1b, respectively, are displaced while narrowing the gap between them, and the rotor 1 is moved to a predetermined position. The contact points 2a and 3a come into contact with each other depending on the amount of rotation. The contact state between the contact point 2a and the contact point 3a can be detected as a collision detection signal by a change in the current supplied from the output terminals 6a, 6b, 8a, 8b. Here, a circuit diagram of the collision detection device 20 is shown in FIG. As shown in FIG. 6, in the present embodiment, a collision detection signal is output to an ignition circuit and a monitor circuit (not shown) via the output terminals 6b and 8a, and a diagnostic diagram on the ECU side (not shown) is output via the output terminals 6a and 8b. The detection signal is output to the register.

The stopper 16 bends toward the gap 9 around the contact portion 16a when the stopper 16 contacts the weight 4.
Thereby, the kinetic energy due to the rotation of the weight 4 is converted into the elastic energy of the stopper 16, and the stopper 16 acts as a damper when it comes into contact with the weight 4,
Is absorbed by the stopper 16. In this way, by providing the gap 9 between the stopper 16 and the cover 10 and bending the stopper 16 when contacting the weight 4, the damper action is increased, so that the weight 4 contacts the stopper 16. At this time, chattering between the contacts 2a, 3a can be prevented, the holding time of the contact on can be increased, and the collision detection signal can be stably output. In the present embodiment, with the above configuration, the contact-on holding time can be improved by about 1.3 times as compared with the configuration in which the gap 9 is not provided between the stopper 16 and the cover 10. did it.

In the above embodiment, the weight 4 and the position of the center of gravity of the weight 4 are adjusted by forming the hole 4a in the weight 4. Thereby, the sensitivity characteristic of the collision detection device 20 can be changed without changing the outer shape of the weight 4. FIG. 8 schematically shows changes in the sensitivity characteristics depending on the presence or absence of the hole 4a. In FIG. 8, the vertical axis represents the value (G) of the applied acceleration, the horizontal axis represents the pulse width (cycle) (ms) of the acceleration waveform, and the curve represents the operation level at which the contact turns on. As shown in FIG. 8, by providing the hole 4a in the weight 4, the operation level at which the contact is turned on can be increased. Utilizing this characteristic, for example, in the case of a side collision as compared with the case of a frontal collision, the acceleration acting is a high frequency and its level is large, so by providing a hole in the weight of the collision detection device for a frontal collision, The weight for side impact can be easily formed. In addition, since the outer shape of the weight 4 does not change, the resin mold can be shared, and the cost merit is large.

In the above embodiment, the insert fittings 14, 1
5 is provided with bent portions 14c and 15c, respectively. By providing the bent portions 14c and 15c, the bending strength of the insert metal fittings 14 and 15 in the thickness direction can be increased, and the metal fitting 1 can be formed at the time of resin insert molding.
Since 4 and 15 can be fixed, insert molding of thin metal fittings into the thin resin part is possible. For example, FIG.
The state when resin insert molding is performed using the insert metal fitting 15 having no bent portion at 0 (b) is schematically shown. However, since the insert metal fitting 15 does not have a bent portion, the metal fitting 15 swings left and right during insert molding. It will be molded in that state. Therefore, as shown in FIG. 10B, the metal fitting 15 sticks out to the inner wall surface of the cover 10. On the other hand, FIG.
When the bent portion 15c is provided on the metal fitting 15 as shown in FIG. 3, the strength against bending is increased, so that the amount of runout on the left and right during insert molding can be reduced, and the metal fitting 15 is fixed by the metal mold 21 and the metal mold 22. Therefore, the resin insert molding can be performed in a state where the metal fitting 15 is accurately fixed at the predetermined position and the predetermined posture. By doing this,
It is possible to reduce the thickness of the resin insert-molded product and ensure airtightness. Further, after the insert molding, the insert position of the metal fitting 15 and its state can be confirmed from the appearance, so that the quality control is easy.

Further, as shown in FIG. 9, the insert fittings 14 and 15 have asymmetrical shaped portions 14d and 15d, respectively.
Since this is formed, misplacement is prevented. For example,
As shown in FIG. 11B, the insert fittings 14, 15
When the respective bent portions 14c, 15c are arranged rightward, the bent portion 15c is in a state of protruding to the inner peripheral surface of the cover 10. In this way, the insert fittings 14, 15
Depending on the arrangement, one or both of the bent portions 14c and 15c may be projected to the inner peripheral surface of the cover 10, so that a product defect occurs. However, as in this embodiment,
Asymmetrical shape parts 14d, 15 on the insert fittings 14, 15
d is provided and the insert fittings 14 and 1 are used as marks.
By disposing 5 in the mold 22, the insert fitting 14,
As shown in FIG. 11A, the arrangement posture of 15 can be set to a regular posture, and the generation of defective products can be prevented. Further, as shown in FIG. 11 (b), the insert fitting 1
When 4 and 15 are arranged, the core mold forming the inner shape of the cover 10 and the bent portion 15c of the insert metal fitting 15 interfere with each other, which may damage the core mold. By arranging in the normal posture shown in FIG. 11A, the core die and the insert fitting 15 do not interfere with each other, and the die can be prevented from being damaged.

Further, the asymmetrical shaped portions 14d and 15d are formed by notching the inside of the root portions of the fixed terminals 14a and 15b. At this time, when the present apparatus 20 is arranged on a printed circuit board (not shown), it is removed by Δ as shown in FIG. As a result, the fulcrum for the printed circuit board is fixed terminals 14a, 1
The end surfaces S1 and S2 on the outer side of the root portion of 5b can be provided, and the distance L between the fulcrums can be lengthened, and the posture thereof can be stabilized when the device 20 is attached to the printed circuit board.
In FIG. 9, the asymmetrical shaped portions 14d and 15d are formed at the bases of the fixed terminals 14a and 15b, but the asymmetrical shaped portion 14d is formed.
You may provide d, 15d at the front-end | tip of the terminals 14a, 15b. Further, although the asymmetrical shape portions 14d and 15d are provided at the bases of the fixed terminals 14a and 15b having a diagonal relationship, they may be provided on the side of the fixed terminals 14b and 15a having another diagonal relationship. In short, if the orientation is clearly recognizable at the time of disposing the insert fittings 14 and 15, the asymmetrical shape portion 14d,
The formation position and shape of 15d are not limited.

In the above embodiment, the stopper 16 has a prismatic shape, but it may have a plate shape or a cylindrical shape for more effective bending. In the above embodiment, the stopper 1
Although 6 is made of EPDM, the stopper 16 may be any resin material having elasticity, and the material thereof is not limited. Also,
The stopper 16 does not necessarily have to be made of a resin material,
You may comprise using another elastic body. For example, the stopper 16 may be configured using an elastic member such as a spring coil or a leaf spring. Although the stopper 16 is fixed to the cover 10 at both ends in the above embodiment, it may be fixed to the housing 13 or another member, and the fixing method is not limited to fixing at both ends as long as sufficient bending can be obtained.

In the above embodiment, the gap 9 is formed between the stopper 16 and the cover 10 by reducing the thickness of the cover 10. However, the gap 9 is changed by changing the shape of the stopper 16 such as by reducing the thickness. It may be provided. In the above-described embodiment, the shape of the hole 4a formed in the weight 4 is circular for facilitating the processing, but other shapes such as a rectangular shape and a triangular shape may be used. It does not have to penetrate. Furthermore, the contact was a normally open contact that was closed when an acceleration of a specified value or more acted on it.
The contact may be a normally closed contact that is opened when an acceleration of a predetermined value or more is applied.

In the above embodiment, the contacts 2a and 3a are provided integrally with the leaf springs 2 and 3, respectively. However, the leaf spring and the contacts are separately provided and are linked with the operation of the leaf spring. It may be configured to change the state of the contact. Furthermore, a general mechanism that changes the state of the contacts in conjunction with the rotation of the rotor,
For example, the contacts may be operated by a link mechanism or the like. Further, although the weight 4 and the rotor 1 are rotatably supported around the shaft 5, the weight 4 and the rotor 1 and the shaft 5 are fixed, a bearing is provided in the housing 13, and the shaft 5 is provided with respect to the bearing. It may be rotatably supported.

As described above, according to the present invention, the stopper is bent at the time of contact with the weight, and the shock caused by the rotation of the weight is absorbed by the stopper, so that chattering between the contacts can be prevented and the contact is turned on. The holding time can be extended and a stable collision detection signal can be obtained.

[Brief description of drawings]

FIG. 1 is a perspective view showing a configuration of a collision detection device according to a first embodiment of the present invention.

FIG. 2 is a schematic diagram showing the assembly and deployment of the collision detection device according to the first embodiment of the present invention.

FIG. 3 is a structural diagram showing a configuration of a collision detection device according to a first embodiment of the present invention.

FIG. 4 is a structural diagram showing a configuration of the collision detection device according to the first embodiment of the present invention when acceleration is not applied.

FIG. 5 is a structural diagram showing a configuration when acceleration is acting on the collision detection device according to the first embodiment of the present invention.

FIG. 6 is a circuit diagram showing a circuit configuration for processing a collision detection signal in the collision detection device according to the first embodiment of the present invention.

FIG. 7 is a perspective view showing a configuration of a rotor and a weight of the collision detection device according to the first embodiment of the present invention.

FIG. 8 is a schematic diagram showing how the characteristics of the collision detection device according to the first embodiment of the present invention change depending on whether weights are drilled.

FIG. 9 is a configuration diagram showing a structure of an insert fitting of the collision detection device according to the first embodiment of the present invention.

FIG. 10 is a structural diagram showing a resin insert molding result depending on the presence or absence of a bent portion of the insert fitting in the collision detection device according to the first embodiment of the present invention.

FIG. 11 is a structural diagram showing a resin insert molding result depending on the presence or absence of an asymmetrical shape portion of the insert fitting in the collision detection device according to the first embodiment of the present invention.

[Explanation of symbols]

 1 rotor 1a first cam 1b second cam 2, 3 leaf springs 2a, 3a contact 4 weight 4a hole 5 shaft 6a, 6b, 8a, 8b output terminal 9 gap 10 cover 11 sealant 12 base 13 housing 14, 15 insert Metal fittings 14a, 14b, 15a, 15b Fixed terminal 16 Stopper 20 Collision detection device

Claims (6)

[Claims] 1. A collision detection device configured to detect an acceleration of a predetermined value or more by converting the received acceleration into a rotational force and changing the state of a mechanical contact according to the rotational force to receive the acceleration. A weight, a shaft that rotatably supports the weight at a position eccentric to the weight center of gravity of the weight, a rotor that is supported by the shaft and that rotates with the rotation of the weight, and a predetermined rotation of the rotor. A pair of contact members configured to change the state of the pair of contacts depending on the amount of movement, and arranged on the rotation path of the weight to restrict rotation of the weight beyond a predetermined position, and A collision detection device, comprising: an elastic body that bends in the direction of the acting force by the acting force of the regulating means, which is provided with a bendable space. 2. The rotor has a cam, the contact member has a contact, and is composed of a pair of leaf springs erected at a predetermined interval, and the tip end of each leaf spring contacts the cam. Elastically biases the rotor in a direction opposite to the rotating direction of the rotor, and when the acceleration is greater than a predetermined value, the state of the contact is changed by the action of the cam of the rotating rotor. The collision detection device according to claim 1, wherein: 3. The collision detection device according to claim 1, wherein the restricting unit has a beam structure with both ends fixed which is bendable when abutting against the weight. 4. A protective member constituting a casing is provided, wherein the regulating means is fixed at both ends to the protective member, and when the weight comes into contact with the regulating means, a space for allowing the regulating means to bend is provided. The collision detection device according to claim 3, wherein the collision detection device is provided between the regulation means and the protection member. 5. The regulation means is a resin material having elasticity,
The collision detection device according to claim 1, wherein the collision detection device is made of an elastic body such as a rubber material, a coil spring, or a leaf spring. 6. The cam of the rotor comprises a first cam and a second cam, and the pair of leaf springs are in contact with the first cam and the second cam, respectively, when the rotor collides. The first cam and the second cam are biased in the direction opposite to the rotation direction, and the shapes of the first cam and the second cam are such that, at the time of a collision, the action of the rotating cam narrows the gap between the contacts of the pair of leaf springs. The collision detection device according to claim 2, wherein the collision detection device has a closed shape.