JP2001289873A - Shock sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a compact and inexpensive shock sensor which can be easily assembled with a good productivity with a small number of parts and has superior response characteristics when detecting a shock. SOLUTION: This shock sensor has conductive movable lead 23 and fixed lead 22 sealed therein. The leads are constituted symmetrically to be almost totally opposite to each other into a housing 21 from fixed parts 21a and 21b at both end faces of the housing 21. Moreover, the shock sensor has a shock- sensing element 20 stored in a case 25. The sensing element is constituted to be closed when a contact part 23a of the movable lead 23 is elastically deformed into contact with a contact part 22a of the fixed lead 22 when receiving the predetermined or larger shock in a sensing direction to the contact part 22a. In addition, an electromagnetic coil 24 as a closure assistant device which can adjust a sensitivity for the closure state of the contact parts 22a and 23a in accordance with a size of a supplied current value is disposed inside the case 25 to surround the outer periphery of the shock-detecting element 20 surrounding outer peripheries of the contact parts 22a and 23a.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is mainly used for an occupant protection device mounted on a vehicle such as an automobile to detect an impact applied to a vehicle body, or to be attached to precision equipment or the like as a self-quality diagnostic function. The present invention relates to an impact sensor that detects an impact applied to a device body at times.

[0002]

2. Description of the Related Art Conventionally, as this kind of impact sensor, for example, as shown in FIG. 6, a type utilizing a magnetic reed switch 5 has been widely used.

The impact sensor 1 has an exterior case 3 with respect to a frame 2 provided on an automobile body or the like.
The case 3 has a cylindrical shaft 4 which absorbs shock and is arranged along a direction to be detected, a magnetic reed switch 5 inserted in the shaft 4, and a shaft. An annular magnet 6 slidably disposed along the outer peripheral surface in the longitudinal direction of 4 and biases the annular magnet 6 to the inner wall end surface of the case 3 which is separated from the contact portion of the magnetic reed switch 5 in a normal state. A spring 7 is provided, and two connection terminals forming a contact portion of the magnetic reed switch 5 are connected to a detection circuit via a lead wire.

In such a shock sensor 1, when the vehicle itself is running normally including a stop operation in a use state attached to the frame 2 of the vehicle body, an excessively high shock (acceleration) does not act. The state in which the annular magnet 6 remains in contact with the inner wall end surface of the case 3 by the urging force of the spring 7 without moving on the outer peripheral surface of the shaft 4 is maintained. Therefore, the magnetic reed switch 5 remains open because the two connection terminals forming the contact portions are not closed by the magnetic force of the annular magnet 6 and remain open.

[0005] However, when the vehicle itself is running abnormally including a sudden stop operation due to an accident or the like, a high impact is applied to the vehicle body, and if the acceleration accompanying the impact force acts in the direction shown by the arrow, the shaft 4 The annular magnet 6, which is in contact with the inner wall end face of the case 3 due to the urging force of the spring 7 without moving on the outer peripheral surface of the case, receives a negative acceleration that overcomes the urging force of the spring 7, whereby the annular magnet 6 When the magnetic force of the annular magnet 6 becomes larger than a predetermined value, the magnetic reed switch 5 moves to the contact portion of the magnetic reed switch 5 on the outer peripheral surface of the shaft 4 based on the inertial mass.
Are closed by the magnetic force of the annular magnet 6 and turned on.

At this time, if the impact is large, the annular magnet 6 continues to move, and stops when the spring 7 reaches the position where it is completely compressed. In the process so far,
The kinetic energy stored in the annular magnet 6 is once converted into deformation and vibration energy of the spring 7 and the case 3 and the like, and then converted again into kinetic energy of the annular magnet 6 whose direction is reversed.

After that, when the automobile or the like is stopped, the annular magnet 6 is stopped.
When the acceleration applied to the annular magnet 6 becomes equal to or less than a predetermined value, the annular magnet 6
Can no longer overcome the urging force of the spring 7 and again moves from the contact portion of the magnetic reed switch 5 on the outer peripheral surface of the shaft 4 to the inner wall end surface side of the case 3 by the urging force of the spring 7 to return to the original position. Will be returned. At this time,
When the magnetic force of the annular magnet 6 acting on the contact portion of the magnetic reed switch 5 becomes equal to or less than a predetermined value, the contact portion of the magnetic reed switch 5 is turned off again.

That is, in the magnetic reed switch 5, the on state of the contact portion is maintained from the above-described on-conversion to the off-conversion. By the way, in occupant protection devices such as automobiles,
When the contact portion of the magnetic reed switch 5 in the impact sensor 1 is energized, a system such as a safety control device that detects the energized state is activated to deploy an airbag or the like, thereby ensuring the safety of the occupant. Has become.

[0009]

In the case of the above-mentioned impact sensor, the number of parts is large, and high precision is required for each part, so that the parts cost is increased and the assembling process is complicated, resulting in production. There is a problem that the cost is high due to low performance.

Further, in the case of the above-described impact sensor, since the annular magnet moves on the outer peripheral surface of the shaft in the case, there is a problem that the size of the impact sensor is increased as a whole.

Further, in the case of the above-described shock sensor, not only can the recent demand for miniaturization not be met, but also the response characteristics upon shock detection advantageous for a large sensor due to its structure (the ON state at the contact portion of the magnetic reed switch). Continuity) cannot be obtained satisfactorily.

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem. The technical problems of the present invention are that the number of parts is small, the assembly can be easily performed with good productivity, and the response characteristics upon impact detection are excellent. An object of the present invention is to provide a small and inexpensive impact sensor.

[0013]

According to the present invention, a housing extending in another direction substantially perpendicular to one direction for detecting an impact, and the housing is provided from both end surfaces parallel to the one direction. It is enclosed and deployed in a pair configuration so that it extends in the other direction toward the body and substantially faces each other, and the contact portion on the tip side of one of the pair configuration sealed in the housing is the other. A conductive movable lead and a fixed lead which are elastically deformed and come into a closed state when subjected to a predetermined impact or more in the one direction with respect to a contact portion on the distal end side enclosed in the housing. An impact sensor having an impact detection element is obtained.

Further, according to the present invention, in the above-described shock sensor, the shock sensor is disposed so as to cover at least the outer periphery of the contact portion of the movable lead and the fixed lead, and covers the outer periphery of the shock detecting element. An impact sensor having an electromagnetic coil as a closing assist device capable of adjusting the sensitivity of the contact portion in the closed state according to the size is obtained.

Further, according to the present invention, in any one of the above impact sensors, the movable lead and the fixed lead each have a lead connection portion projecting from both end surfaces of the housing in the other direction. An impact sensor is provided which is fixedly contacted to internal terminals formed on inner surfaces of both end faces facing in parallel to one direction of a case for housing the impact detecting element and the electromagnetic coil.

On the other hand, according to the present invention, in the above-described impact sensor, the electromagnetic coil is disposed on the inner surface extending in the other direction of the case, and on the outer surface extending in the other direction of the case. An impact sensor is obtained which is fixed by contact with the formed first external terminal.

On the other hand, according to the present invention, in the above-mentioned impact sensor, the internal terminal is connected to the second external terminal formed on the outer surface extending in the other direction of the case, and the first external terminal is provided. The second external terminal has a tip portion extending in one direction and another direction substantially perpendicular to the other direction, thereby obtaining an impact sensor for surface mounting.

[0018]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings.

FIG. 1 is a plan view showing a partial cross section of a basic structure of an impact detecting element used in an impact sensor according to one embodiment of the present invention.

The shock detecting element 20 has a housing 21 extending in another direction (horizontal direction in the figure) substantially perpendicular to one direction (front and rear direction in the figure) indicated by an arrow for detecting a shock.
And fixing portions 21 on both end surfaces parallel to one direction of the housing 21.
a, 21b, each extending in the other direction toward the inside of the housing 21 and enclosed and arranged in a pair configuration so that substantially the entire body is opposed to each other, and sealed in the housing 21 of one of the pair configurations. When the contact portion 23a on the distal end side receives a predetermined impact or more in one direction with respect to the contact portion 22a on the distal end sealed in the housing 21 of the other end, the contact portion 23a elastically deforms and comes into a closed state. Movable lead 23 and fixed lead 22.

That is, in short, in other words, the movable lead 23 and the fixed lead 22 are located at opposite positions in the housing 21 via the fixing portions 21a and 21b on both end surfaces of the housing 21, respectively. Side contact portions 23a and 22a are arranged.

FIG. 2 is a plan view showing a partial cross section of a basic structure of the shock sensor 10 according to one embodiment using the shock detecting element 20.

The shock sensor 10 has an electromagnetic force as a closing assist device that can adjust the sensitivity of the contact portions 22a and 23a in the closed state according to the magnitude of the supplied current value. The electromagnetic coil 24 is connected to the fixed lead 22 and the movable lead 2
3 is arranged and stored so as to cover the outer periphery of the impact detection element 20 including the outer periphery of the contact portions 22a and 23a.

More specifically, after the electromagnetic coil 24 is disposed on the inner surface extending in the other direction of the case 25,
5 is provided with an electromagnetic coil 24 at a substantially central portion thereof.
The fixed portions 2 on both end surfaces of the housing 21 of the fixed lead 22 and the movable lead 23 so as to be arranged so as to cover the outer peripheral surface thereof.
Internal terminals 26 formed on the inner surfaces of both end surfaces of the lead connection portions 22b and 23b protruding in the other direction from the first and second cases 1b and 21a, respectively.
a and 26b, and fix the electromagnetic coil 24 to the case 25.
Are fixed to the first external terminals 32a and 32b formed on the outer surface extending in the other direction.
The second external terminals 34b, 34 formed on the outer surfaces extending in the other direction of the case 25 respectively at both ends of the external terminals a, 26b.
d and the second external terminals 34a and 34c. The second side of the outer surface extending in the other direction of the case 25
The first external terminals 32c and 32d formed near the external terminals 34b and 34d are for grounding.

That is, to put it simply, the electromagnetic coil 24
The fixed leads 22 and the distal ends of the lead connection portions 22b and 23b protruding from the fixed portions 21b and 21a on both end surfaces of the housing 21 of the movable lead 23 are provided on the outer surface of the case 25, respectively. External terminals 32 a and 32 b and internal terminals 26 formed on inner surfaces of both end surfaces of case 25.
a and 26b, and are connected to second external terminals 34b and 34d and second external terminals 34a and 34c provided on the outer surface of the case 25.

The shock sensor 10 having such a configuration has a different number of parts from the conventional type in which a magnetic reed switch is provided in the shaft and the outer peripheral surface of the shaft is moved by an annular magnet. It is small and has a small structure that can be easily assembled.

When the impact sensor 10 is mounted on a frame or the like of a vehicle body and the vehicle itself runs abnormally, including a sudden stop operation due to an accident or the like, a high impact exceeding a predetermined level is applied to the vehicle body. When the acceleration accompanying the impact acts in the direction indicated by the arrow, the impact detecting element 2
0, the movable lead 23 receives a relatively large negative acceleration in the direction indicated by the arrow, and the contact portion 23a
Are in elastic contact with and come into contact with the contact portion 22a on the distal end side of the fixed lead 22. As a result, in the shock detecting element 20, the contact portions 22 of the fixed lead 22 and the movable lead 23 are
a and 23a are closed and turned on.

The on state is such that the contact portion 23 on the tip side of the movable lead 23 is
When the negative acceleration is released at (a) (impact becomes less than a predetermined value), the contact portion 23a on the distal end side of the movable lead 23 is returned to the initial state by the elastic restoring force of the movable lead 23 itself, and the contact portion 22a, The portion between 23a is in an open state and is turned off.

Incidentally, in the case of the shock sensor 10, an electromagnetic coil 24 as a closing auxiliary device is provided on the outer periphery of the shock detecting element 20, and via external terminals 32a and 32b provided on the outer surface of the case 25. When a constant current is applied to the electromagnetic coil 24 to generate a magnetic field having a constant strength, and the strength of the magnetic field causes the movable lead 23 to generate a magnetic attraction force with the fixed lead 23, the current value is reduced. The sensitivity of the closed state of the contact portions 22a and 23a can be adjusted by changing the strength of the magnetic field.

That is, when a magnetic field generated by the electromagnetic coil 24 is applied and used together, for example, when a shock is applied to the shock sensor 10, the movable lead 23 is attached to the fixed lead 22.
In this case, when the resultant force of the magnetic attraction force due to the applied magnetic field and the inertia force generated by the impact becomes larger than the rigidity of the movable lead 23, the movable lead is moved. The contact portion 23 on the tip side of
a comes into contact with the contact portion 22a on the tip end side of the fixed lead 22. As a result, by changing the magnitude of the current supplied to the electromagnetic coil 24, a closed state suitable for the magnitude of the impact to be detected is detected. Can be obtained.

However, in the case of the closed state, if the inertial force generated by the impact is eliminated, the rigidity of the movable lead 23 causes the contact portion 23a to separate from the contact portion 22a of the fixed lead 22. 24, the contact portion 2
Since a certain magnetic attraction force acts between the contact portions 2a and 23a, the contact portions 22a and 23a are hard to be dissociated, and the contact portions
It is possible to extend the time during which the 2a and 23a are in contact (the duration of the ON state), and to maintain good response characteristics upon impact detection.

FIG. 3 is a perspective view showing the external structure of the shock sensor 10. As shown in FIG. Here, the case 25 itself is a box type that can be attached and detached at the upper and lower portions, and a portion near the center of the attachment / detachment surface in the thickness direction on both opposing side surfaces in the longitudinal direction is tapered along the longitudinal direction. Due to the protruding shape, the shape of both end surfaces parallel to one direction indicated by an arrow for detecting an impact is substantially hexagonal, and the above-described first external terminal provided on the lower outer peripheral surface 32a-
The tip of each of 32d (however, 32a and 32d are not shown) and the second external terminals 34a to 34d (however, 34a and 32b are not shown) are one direction for detecting an impact and the longitudinal direction of the case 25. The drawing shows a state in which it extends in another direction substantially perpendicular to the direction and is used for surface mounting. Here, the electromagnetic coil 2 as a closing auxiliary device is used.
4 is an external terminal 3 of the first external terminals 32a to 32d.
It is assumed that it is supported and fixed to 2b and 32d.

FIG. 4 shows an impact sensor 10 'according to another embodiment in which the terminals and the exterior of the impact sensor 10 are partially changed.
FIG. 2 is a perspective view showing an external configuration of the apparatus. This impact sensor 1
In the case of 0 ', the central portion of the upper part of the case 25' itself has a shape protruding in a tapered shape along the longitudinal direction, so that the shape of both end faces parallel to one direction indicated by the arrow for detecting the impact is substantially pentagonal. In addition to the shape, the internal structure is the same as that of the shock sensor 10 except that only two first external terminals 32b 'and 32c' are fixed to the electromagnetic coil 24 in contact with each other. A configuration in which two second external terminals 34d 'and 34c' provided on the outer surface of the case 25 'are connected to internal terminals 26a and 26b provided on inner surfaces of both end surfaces parallel to the direction. It has become.

That is, in short, in the case of the shock sensor 10 ′, in the shock sensor 10 of the first embodiment, a total of eight first external terminals 3 are provided on the outer peripheral surface of the lower portion of the case 25.
2a to 32d and the second external terminals 34a to 34d are provided, whereas a total of four first external terminals 32b 'and 32c' and a second external terminal 34c ', 34d 'is provided and the number of terminals is reduced. Incidentally, the distal ends of the first external terminals 32b 'and 32c' and the second external terminals 34c 'and 34d' are also substantially in the one direction for detecting an impact and the other direction which is the longitudinal direction of the case 25 '. It extends in another vertical direction and is provided for surface mounting. Also, here
It is assumed that the electromagnetic coil 24 as a closing assist device is supported and fixed to the first external terminals 32b 'and 32c'.

FIG. 5 is a perspective view showing an external structure of an impact sensor 10 "according to another embodiment in which the terminals of the impact sensor 10 are partially changed.
Although a case 25 having the same shape as that of the impact sensor 10 of FIG. 3 is used, first external terminals 32a "to 32d" provided on a lower outer peripheral surface (however, 32a "and 32d" are not shown). And second external terminals 34a "to 34d"
(However, 34a "and 34b" are not shown). Each of the ends of the substrate is bent and is parallel to a plane including one direction indicated by an arrow for detecting an impact and the other direction which is the longitudinal direction of the case 25. The difference is that the shape has been improved as a shape that simplifies surface mounting with respect to the mounting surface.
Note that, also in this case, the electromagnetic coil 24 as the closing assist device is connected to the external terminal 3 of the first external terminals 32a "to 32d".
2b "and 32d" are supported and fixed.

In any case, the impact sensor 1 of each embodiment
Cases 25 and 25 'used in 0, 10' and 10 "are hollow resin or filled resin, external terminals 32a to 32d,
32a "to 32d", 34a to 34d, 34a "to 34
d "or the external terminals 32b ', 32c', 34c ', 3
It can be easily formed of a hollow metal insulated from 4d 'or a metal filled with resin.

It should be noted that the impact sensors 10,
Although 10 'and 10 "have been described as being used by being attached to a frame or the like of a vehicle body of an automobile, the shock sensors 10, 10' and 10" having such a configuration are attached to precision equipment and the like besides the automobile. The present invention has been described in each embodiment because it can be used for detecting the impact applied to the device body during its transportation, and in this case, the precision device can have a self-quality diagnosis function. Impact sensor 10,
It is not limited to 10 ', 10 ".

[0038]

As described above, according to the shock sensor of the present invention, the configuration of the conventional magnetic reed switch is improved,
A pair of conductive movable leads and fixed leads are enclosed and arranged in a pair configuration so that substantially the entire body faces each other from the both end surfaces of the housing. In the detection direction, when a shock greater than a predetermined value is applied, the contact element is closed by elastic deformation and the contact is closed according to the magnitude of the supplied current. The electromagnetic coil as a closing auxiliary device that can adjust the sensitivity of the fixed lead and the movable lead is arranged so as to cover the outer periphery of the shock detecting element including the outer periphery of the contact portion in the movable lead, so that the inertial force generated by the impact and the When the resultant force due to the magnetic attraction by the applied magnetic field becomes greater than the rigidity of the movable lead, the contact of the movable lead contacts the contact of the fixed lead, and It is possible to obtain a sensitivity of closed state commensurate with the magnitude of the impact to be detected by changing the magnitude of the current supplied to the coil. As a result, a compact and inexpensive impact sensor having a small number of parts, being easily assembled with good productivity, and having excellent response characteristics upon impact detection can be obtained. In particular, if this impact sensor is applied to a safety control device of an automobile, the system can be operated properly. If it is used for the purpose of detection, it can be provided with an impact diagnostic function (self-quality diagnostic function) for precision equipment, which is extremely useful in industry.

[Brief description of the drawings]

FIG. 1 is a plan view showing a basic structure of an impact detecting element used in an impact sensor according to an embodiment of the present invention in a partial cross section.

FIG. 2 is a plan view showing a partial cross section of a basic configuration of an impact sensor according to an embodiment using the impact detection element shown in FIG.

FIG. 3 is a perspective view showing an external configuration of the impact sensor shown in FIG. 2;

FIG. 4 is a perspective view showing an external configuration of an impact sensor according to another embodiment in which a terminal and an exterior of the impact sensor shown in FIG. 2 are partially changed.

FIG. 5 is a perspective view showing an external configuration of an impact sensor according to another embodiment in which terminals of the impact sensor shown in FIG. 2 are partially changed.

FIG. 6 is a plan view showing a basic configuration of a conventional impact sensor in a partial cross section.

[Explanation of symbols]

1, 10, 10 ', 10 "Impact sensor 2 Frame 3 Case 4 Shaft 5 Magnetic reed switch 6 Annular magnet 7 Spring 20 Impact detection element 21 Housing 21a, 21b Fixed part 22 Fixed lead 22a, 23a Contact part 22b, 23b Lead Connection part 23 Movable lead 24 Electromagnetic coil 25 Case 26a, 26b Internal terminal 32a-32d, 32b ', 32c', 32a "-32
d ", 34a-34d, 34c ', 34d', 34a"
~ 34d "external terminal

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (Reference) H01H 35/14 G01P 15/00 D 36/00 302 15/08 P

Claims (5)

[Claims] 1. A housing extending in another direction substantially perpendicular to one direction for detecting an impact, and both ends of the housing parallel to the one direction are respectively inserted into the housing in the other direction. It extends and is enclosed and arranged in a pair configuration so that substantially the whole is opposed to each other, and a contact portion on the tip side sealed in the housing of one of the pair configurations is sealed in the housing of the other one. And a shock detecting element comprising a conductive movable lead and a fixed lead which are brought into a closed state by being elastically deformed when they receive a predetermined impact or more in the one direction with respect to the contact portion on the tip side. An impact sensor comprising: 2. The shock sensor according to claim 1, wherein the current is supplied while being arranged so as to cover at least the outer periphery of the contact portion of the movable lead and the fixed lead and the outer periphery of the impact detection element. An impact sensor comprising an electromagnetic coil as a closing assist device capable of adjusting the sensitivity of the contact portion in a closed state according to the magnitude of the value. 3. The shock sensor according to claim 1, wherein the movable lead and the fixed lead each have a lead connection portion protruding from both end surfaces of the housing in the other direction, and the lead connection portion. Is a contact sensor fixed to an internal terminal formed on an inner surface of both end surfaces of the case for housing the shock detecting element and the electromagnetic coil, which faces in parallel with the one direction. 4. The impact sensor according to claim 3, wherein the electromagnetic coil is disposed on an inner surface of the case extending in the other direction and an outer surface of the case extending in the other direction. An impact sensor, which is fixedly contacted to a first external terminal formed on the first external terminal. 5. The shock sensor according to claim 4, wherein the internal terminal is connected to a second external terminal formed on an outer surface of the case extending in the other direction, and the first terminal is connected to the first terminal. The impact sensor according to claim 1, wherein each of the external terminal and the second external terminal has a tip portion extending in another direction substantially perpendicular to the one direction and the other direction and used for surface mounting.