JP3017981U - Collision sensor - Google Patents

Abstract

(57) [Summary] [Objective] To provide a flapper type collision sensor capable of improving the durability of the flapper supporting portion and prolonging the contact closing time. In the case (2), a plate-like flapper (3) that rotates due to inertial force in the thickness direction of the vehicle when the vehicle receives an impact, a fixed contact piece (13) and a movable contact piece (35). An opening / closing means that constitutes a contact and is normally open, but when the flapper (3) is rotated, the movable contact piece (35) is displaced to close the contact, thereby closing the starting circuit of the occupant protection device. In the collision sensor provided with, a bias means for urging the flapper (3) in a direction opposite to the inertial force is provided separately from the opening / closing means.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a collision sensor used in a vehicle occupant protection system, and more particularly to a flapper type collision sensor.

[0002]

[Prior art]

 A conventional flapper type collision sensor of this type is known from USP 5,231,253. This collision sensor will be described with reference to FIGS. 5 is a sectional view of the collision sensor, and FIG. 6 is a sectional view taken along line AA of FIG. 5 and 6, the collision sensor 1 is provided with a storage case 2 in the shape of a rectangular parallelepiped having three flat faces, and the storage case 2 is attached to the side door on the left side of the drawings. The arrow in the figure indicates the direction of impact. A rectangular plate-shaped flapper 3 extends in a diagonal direction on the bottom surface of the storage case 2 (on the left side in the drawing). The flapper 3 is fixed to one end of a resin hinge 6 at the center of one side thereof. The other end of is fixed to the side wall of the storage case 2. Therefore, the flapper 3 is rotatable in its thickness direction with the resin hinge 6 as a fulcrum. Further, a slight gap 7 is formed between the outer circumference of the flapper 3 and the side wall of the storage case 2, and when the flapper 3 rotates, the air flow passing through the gap 7 acts as an air damper. It is like this. On the side wall of the storage case on the opposite side of the flapper 3, a movable contact piece 4 made of an elastic wire and formed in a mountain shape is provided so as to project inward, and the top portion 4a of the mountain shape contacts the flapper 3, The tip portion 4b is located away from the lid surface 2a of the storage case 2. A fixed contact piece 5 is provided at a position on the lid surface 2a of the storage case corresponding to the tip 4b of the movable contact piece. The proximal ends of the movable contact piece 4 and the fixed contact piece 5 are led out to the outside of the storage case 2 and are respectively connected to an activating circuit of an occupant protection device (for example, a side airbag) (not shown). It constitutes a switch (opening / closing means).

In this collision sensor, when the vehicle receives an impact from the direction of the arrow, the flapper 3 rotates in the direction of the arrow due to its inertial force. Then, the movable contact piece 4 is pressed by the flapper 3 and is displaced in the rotation direction thereof, but at this time, the flapper 3 is biased in the counter rotation direction by the elastic force corresponding to the displacement. That is, it acts as a bias spring. Therefore, when the inertial force of the flapper 3 does not reach the predetermined value (sensitivity of the collision sensor), the flapper 3 is pushed back and returns to the initial position. On the other hand, when the inertial force of the flapper 3 reaches a predetermined value, the tip 4b of the movable contact piece 4 comes into contact with the fixed contact piece 5 and the activation circuit of the occupant protection device is closed. Is started. It should be noted that noise-like vibrations due to rough roads are absorbed by the air damper action of the gap 7 to prevent malfunction. Since the flapper type collision sensor has a flat shape, it has an advantage that it has a small installation space and is suitable for, for example, a side airbag device.

[0004]

[Problems to be solved by the device]

 However, the collision sensor has a problem that the contact closing time cannot be set long because the movable contact piece 4 serves as a contact and also serves as a bias means.

The present invention has been made in view of the above problems of the prior art, and an object of the present invention is to provide a flapper type collision sensor capable of prolonging the contact closing time. To do.

[0006]

[Means for Solving the Problems]

 In order to solve the above-mentioned problems, a collision sensor of the present invention comprises a plate-shaped flapper, which is provided in a case so as to be rotatable by an inertial force in a thickness direction thereof when a vehicle receives an impact, and a fixed contact piece. And the movable contact piece constitute a contact, which is normally open, but when the flapper rotates, the movable contact piece displaces and closes the contact to close the starting circuit of the occupant protection device. And a bias means for urging the flapper in a direction opposite to the inertial force, which is provided separately from the opening / closing means.

Further, the bias means is a panel which is interposed between the case and the flapper and which biases the flapper with an elastic force generated by rotation of the flapper by the inertial force. be able to.

The bias means may be a magnet that holds the flapper in the case with a predetermined magnetic force in a direction opposite to the inertial force.

Further, the bias means may be a leaf spring having one end fixed to a part of the outer circumference of the flapper and the other end fixed to the case.

A means for electrically detecting breakage of the leaf spring may be provided.

Further, a rotation shaft is set in a part of the outer circumference of the flapper in a tangential direction thereof, and rotation support means for supporting the flapper to the case so as to be rotatable around the rotation shaft is provided. can do.

[0012]

[Action]

 According to the above configuration, the flapper and the fixed contact piece and the movable contact piece constitute a contact point in the case, and although the contact is normally open, when the flapper rotates, the movable contact piece is displaced and A collision sensor provided with an opening / closing means for closing contacts and closing a starting circuit of an occupant protection device, wherein a bias means for urging the flapper in a direction opposite to its inertial force is provided separately from the opening / closing means. Then, since the contact function and the biasing function are separated, the contact closing time can be extended.

Further, if the bias means is a spring that is interposed between the case and the flapper and biases the flapper with an elastic force generated by rotation of the flapper due to inertial force, after the contact is closed. In addition, the flapper can be rotated so that the contact closing time can be increased.

If the bias means is a magnet that holds the flapper in a case with a predetermined magnetic force in a direction opposite to the inertial force, the magnetic force becomes small in inverse proportion to the rotation of the flapper, so that the contact point is reduced. The closing time can be further lengthened, the magnetic force can be controlled accurately and continuously, and the bias due to the magnetic force is generally easier to adjust than the spring, so the accuracy of the bias force can be improved.

Further, when the bias means is a leaf spring having one end fixed to a part of the outer circumference of the flapper and the other end fixed to the case, the flapper support means and the bias means are combined. Therefore, the structure can be simplified.

Further, when the means for electrically detecting the breakage of the leaf spring is provided, the reliability of the collision sensor can be improved by diagnosing the breakage due to the fatigue breakage of the leaf panel.

Further, since the rotation support means provided on a part of the outer circumference of the flapper rotatably supports the flapper on the case, fatigue damage of the hinge can be prevented.

[0018]

【Example】

 Hereinafter, embodiments of the present invention will be described with reference to the drawings. First, the first embodiment will be described with reference to FIG. FIG. 1 is a sectional view showing the structure of the collision sensor of the first embodiment. In FIG. 1, parts having the same actions as those in FIGS. 6 and 7 are designated by the same reference numerals, and the description thereof will be omitted.

First, the configuration will be described. 1 is essentially different from FIGS. 5 and 6 in that instead of the movable contact piece 4 also serving as the bias in FIG. 5, a coil spring 14 for bias, a dedicated movable contact piece 35 and a fixed contact piece 13 are provided. The point provided is that the flapper 3 is supported by the storage case 2 by a rotation support means composed of a rotation shaft 9 and a bearing 10 instead of the resin hinge 6 of FIG. First, the rotation support means will be described. The arrow in the figure indicates the direction of impact, and the storage case 2 is attached to the left side of the drawing, for example, to a side door. The storage case 2 is made of resin and is composed of a storage member 2a formed as shown in the figure and a lid member 2b fitted to the storage member 2a. The rectangular flapper 3 is arranged along the cover member 2b with a minute gap 7 between the rectangular flapper 3 and the storage member 2a. A rotary shaft 9 is provided on one side of the flapper 3 in a direction along the side, and bearings 10 and 10 for rotatably housing the rotary shaft are provided at corresponding positions of the storage member 2a. In this case, the rotary shaft 9 may be provided so as to project on the storage member 2a side, and the bearing 10 may be provided on the flapper 3 side.

The coil spring 14 is formed of a compression spring, and is inserted between the storage member 2 a and the flapper 3 in the substantially central portion of the storage case 2. The fixed contact piece 13 is made of a plate-shaped elastic contact material and is provided on both sides of the coil spring 14. The base end of the fixed contact piece 13 is fixed to the bottom surface of the storage member 2a, and the tip extends obliquely toward the tip of the flapper 3 and is located away from the flapper 3. A plate-like movable contact piece 35 is arranged at a position corresponding to the tip of the fixed contact piece 13 of the flapper 3. Further, 31 is a stopper, and the flapper 3 is rotatable, that is, it can be pushed in by a distance d, after coming into contact with the fixed contact piece 13 and further coming into contact with the stopper 31. Further, the two fixed contact pieces 13 are connected to the two lead wires 11 and 12, respectively. Therefore, when the two fixed contact pieces 13 and the movable contact piece 35 come into contact with each other, they are connected in series, as shown in the figure. The occupant protection device startup circuit is closed.

A diagnostic resistor 10 is connected between the lead wires 11 and 12. Reference numeral 30 is a screw for adjusting the stroke of the flapper 3. Since the flapper 3 is urged to the right in the drawing by the coil panel 14, the flapper 3 is operated by moving the screw 30 back and forth. The initial position of can be adjusted.

Next, the operation will be described. When a shock is applied from the direction of the arrow, the flapper 3 rotates due to inertial force. When the impact is below the set sensitivity, the flapper 3 is pushed back to the original position by the elastic force of the coil spring 4, and when the impact exceeds the set sensitivity, the flapper 3 is rotated to the two-dot chain line position, which allows the movement. The contact piece 35 is also displaced to the position of the alternate long and two short dashes line and comes into contact with the fixed contact piece 13, and the contact is closed. Further, at this time, since the flapper 3 is supported by the rotary shaft and the bearing, the fear of fatigue damage unlike the conventional resin hinge is eliminated, and the durability of the collision sensor can be improved.

The flapper 3 is biased by the coil spring 14 and is pushed back by the coil spring 14 in the case of impact less than the sensitivity. When an impact exceeding the sensitivity setting is detected, the flapper 3 overcomes the elastic force of the coil spring 14 and comes into contact with the fixed contact piece 13, and the contact point with the movable contact piece 13 is closed. It rotates together with the fixed contact piece 13 until it comes into contact with the stopper 31 of. Therefore, the closing continuation time can be kept long. According to the measurement example, the closing time of the conventional collision sensor device was about 1 ms, but it was about 4 ms in this embodiment.

Next, a second embodiment of the present invention will be described with reference to FIG. 2 is different from FIG. 1 in that a magnet 16 is used as the bias means instead of the coil spring 14 of FIG. That is, a disk-shaped biasing plate 3a made of a magnetic material (a steel plate in the present embodiment) is arranged in the substantially central portion of the flapper 3, and a position corresponding to the biasing plate 3a of the lid member 2b is provided. A circular concave portion 2c is provided, a keeper 16 made of a magnetic material (a steel plate in this embodiment) is arranged in the concave portion 2c, and a short cylindrical shape made of rare earth is provided between the keeper 16 and the biasing plate 3a. The magnet 15 is arranged. The magnetic force of the magnet 15 is set to overcome the magnetic force and rotate when the flapper 3 has a predetermined inertial force (sensitivity). With such a configuration, the flapper 3 does not rotate when the impact force is less than or equal to the set sensitivity, and rotates when the impact force is greater than or equal to the set sensitivity to close the contacts of the fixed contact piece 13 and the movable contact piece 13. With the coil spring 14 of FIG. 1, since the elastic force increases in proportion to the displacement of the flapper 3, the flapper 3 can easily return to its original position, but in the case of the magnet 16 of this embodiment, the flapper 3 rotates. Since the magnetic force is reduced in inverse proportion to, it is difficult for the flapper 3 to return, and therefore the contact closing time can be further lengthened. According to an actual measurement example, the closing time was about 8 ms. Further, in the case of the coil spring shown in FIG. 1, the characteristics of the spring are likely to vary, but in the case of the magnet 16 of the present embodiment, the magnetic force can be continuously controlled with high precision, so that the sensitivity adjustment is easy.

Next, a third embodiment of the present invention will be described with reference to FIG. FIG. 3 is a sectional view showing the structure of the collision sensor of the third embodiment. 3 is different from FIG. 2 in that a leaf spring 17 is provided in place of the magnet 16 as the biasing means and the rotation supporting means 9, 10 as the supporting means for the flapper 3. That is, one end of the rectangular leaf spring 17 is fixed to one side of the flapper 3, and the other end is clamped to the side wall of the storage member 2a by the pressing member 18 and fastened and fixed by the bolt 20. With such a configuration, the flapper 3 is rotatable around the fixing portion of the leaf spring 17 to the housing member 2a, and when the flapper 3 is rotated by the inertial force, it is generated in proportion to the rotation amount. The elastic force in the opposite direction acts on the flapper 3 as a biasing force. Therefore, since the leaf spring 17 serves both as the bias means and the flapper supporting means, the number of parts can be reduced and the structure is simplified.

Next, a fourth embodiment of the present invention will be described with reference to FIG. FIG. 4 is a sectional view showing the structure of the collision sensor of the fourth embodiment. 4 is different from FIG. 3 in that the leaf spring 17 is provided with means (23 etc.) for electrically detecting a breakage due to fatigue. That is, the fulcrum 17a of the leaf spring 17 (a boundary line between a portion sandwiched between the pressing member 18 and the receiving portion 2d of the storage member and a free portion) 17a is crossed at two places, and the conductivity is formed in a U-shape. A dianostic band 23 made of a thin film of material is bonded to the back surface of the plate panel 17. In this case, the dianostic band 23 and the plate panel 17 are insulated. One end of the dianostic band 23 is connected to one of the lead wires 11 connected to the activation circuit of the occupant protection device with a lead wire 21, and the other end is connected to a lead wire 22 to a diagnostic circuit (not shown). It is connected. A weak diagnostic current is applied to the dianostic band 23 via the two lead wires 21 and 22, and this diagnostic current is monitored. Therefore, when the leaf spring 17 is broken due to fatigue failure, the dianostic band 23 is also cut at the same time, so that the diagnostic current does not flow, and the presence or absence of the abnormality can be monitored from the outside. As a result, the reliability of the collision sensor can be improved. The dianostic band 23 exemplifies electrical detection means for leaf spring breakage, and in addition, the leaf spring breakage may be detected by, for example, eddy current.

[0027]

[Effect of device]

 The collision sensor of the present invention comprises a flapper in the case, and an opening / closing means for displacing the movable contact piece when the flapper rotates to close the contact point with the fixed contact piece to close the starting circuit of the occupant protection device. In the collision sensor equipped with, if the biasing means for urging the flapper in the direction opposite to the inertial force is provided separately from the opening / closing means, the contact closing function and the biasing function are separated, so that the contact closing time is shortened. It can be taken for a long time.

Further, if the biasing means is a spring interposed between the case and the flapper and biasing the flapper with an elastic force generated by the rotation of the flapper due to the inertial force, the contact point is assumed. Even after closing, a flapper rotatable space is provided so that the contact closing time can be easily obtained.

If the bias means is a magnet that holds the flapper in the case with a predetermined magnetic force in the direction opposite to the inertial force, the magnetic force becomes small in inverse proportion to the rotation of the flapper, so that the contact point is reduced. The closing time can be further lengthened and the magnetic force can be continuously controlled with high precision, so that the precision of the bias force can be improved.

If the biasing means is a leaf spring having one end fixed to a part of the outer circumference of the flapper and the other end fixed to the case, the biasing means also serves as the flapper supporting means and the biasing means. Therefore, the structure can be simplified.

Further, if a means for electrically detecting the breakage of the leaf spring is provided, the reliability of the collision sensor can be improved by diagnosing the breakage due to the fatigue breakage of the leaf panel.

Further, since a rotation supporting means for supporting the flapper in the case is provided on a part of the outer circumference of the flapper so as to be rotatable about a rotation axis set in the tangential direction, the conventional resin is used. Fatigue failure like that of a hinge is prevented and its durability is improved.

[Brief description of drawings]

FIG. 1 is a sectional view showing a structure of a collision sensor according to a first embodiment of the present invention.

FIG. 2 is a sectional view showing a structure of a collision sensor according to a second embodiment of the present invention.

FIG. 3 is a sectional view showing a structure of a collision sensor according to a third embodiment of the present invention.

FIG. 4 is a sectional view showing a structure of a collision sensor according to a fourth embodiment of the present invention.

FIG. 5 is a cross-sectional view showing a configuration of a conventional collision sensor.

6 is a cross-sectional view taken along the line AA of FIG.

[Explanation of symbols]

 2 Storage Case (Case) 3 Flapper 4, 35 Movable Contact Piece (Opening / Closing Means) 5, 13 Fixed Contact Piece (Opening / Closing Means) 9 Rotation Shaft (Rotation Support Means) 10 Bearing (Rotation Support Means) 14 Coil Spring (Spring, Bias Means) ) 15 magnet 17 leaf spring 23 dianostic band (electrical detection means)

Front Page Continuation (72) Inventor Takao Nanjo 1764-1, Kamiinayoshi Mukaihara, Chiyoda-cho, Shinji-gun, Ibaraki Sensor Technology Co., Ltd. Tsukuba Works (72) Yuichi Itabashi 1764-1, Kaminae-kai, Chiyoda-cho, Shinji-gun, Ibaraki Sensor Technology Co., Ltd. Tsukuba Office

Claims (8)

[Scope of utility model registration request] 1. A plate-shaped flapper (3) provided in the case (2) so as to be rotatable in the thickness direction thereof by inertial force when the vehicle receives an impact, and a fixed contact piece (13). A contact is formed with the movable contact piece (35) and is normally open, but when the flapper (3) is rotated, the movable contact piece (35) is displaced and the contact is closed to activate the occupant protection device. In the collision sensor having an opening / closing means for closing the opening / closing means, biasing means (14 etc.) for urging the flapper (3) in a direction opposite to the inertial force is provided as the opening / closing means (35, 13).
A collision sensor characterized by being provided separately from. 2. The bias means is the case (2).
A spring (14) interposed between the flapper (3) and the flapper (3) and urging the flapper (3) with an elastic force generated by rotation of the flapper (3) by the inertial force.
The collision sensor described in. 3. The collision sensor according to claim 1, wherein the bias means is a magnet (15) which holds the flapper (3) in the case (2) with a predetermined magnetic force in a direction opposite to the inertial force. . 4. The collision sensor according to claim 1, wherein the bias means is a leaf spring (17) having one end fixed to a part of an outer circumference of the flapper and the other end fixed to the case. 5. The collision sensor according to claim 4, further comprising means (23) for electrically detecting breakage of the leaf spring (17). 6. A rotation supporting means (9, 9), wherein a rotation axis is set tangentially to a part of the outer circumference of the flapper (3) and the flapper is supported by the case so as to be rotatable around the rotation axis. 10. The collision sensor according to claim 1, wherein the collision sensor is provided. 7. The biasing means includes the case (2).
A spring (14) interposed between the flapper (3) and the flapper (3), and biasing the flapper (3) with an elastic force generated by rotation of the flapper (3) by the inertial force.
The collision sensor described in. 8. The collision sensor according to claim 6, wherein the bias means is a magnet (15) which holds the flapper (3) in the case (2) with a predetermined magnetic force in a direction opposite to the inertial force. .