JPH0573832U - Acceleration / deceleration detector - Google Patents

Abstract

(57) [Abstract] [Purpose] To obtain a highly reliable collision detector that activates the occupant protection device in the event of a collision accident such as a car. [Structure] A detection body 2 composed of a magnet that is moved by an acceleration / deceleration is provided in a casing 1 having a non-magnetic cylindrical hollow portion. A magnetic holding plate 3 for holding the detection body 2 in a steady state, a reed switch 4 that operates in response to the magnetism of the detection body 2 when the detection body 2 moves a predetermined distance due to acceleration / deceleration, and a magnetic focusing pole. It has 5 and 6. The casing 1 aligns the moving axis of the detection body 2 with the traveling direction of the vehicle, and fixes it to the vehicle or the like with the reed switch 4 side as the forward side.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a collision detector that starts the operation of an occupant protection device, for example, an airbag, in the event of a collision accident such as an automobile, and in particular, the detector only detects deceleration due to a collision in one direction. It is characterized by the fact that it is provided with a detection function.

[0002]

[Prior Art]

 Conventionally, as a detector of this type, for example, as shown in Utility Model Application Publication No. 52-14464, a contact ball is placed in an enclosure, and in a steady state, the contact ball is attracted and held by a magnet, When an impact force of a predetermined value or more in a predetermined direction is applied, the contact ball is released from the attraction force of the magnet, moves in a predetermined direction, and the electric contact installed at a position opposite to the movement of the contact ball and the contact ball. An electric closed circuit is created by using to detect a collision.

[0003]

[Problems to be solved by the device]

 In the detector described in the prior art, the contact ball and the electrical contact are sealed in the enclosure in the atmosphere, and a collision accident can occur only rarely. However, even if a collision accident occurs, the electric closed circuit cannot be formed, that is, the collision cannot be detected.

Further, in order to prevent the oxidation of the electric contacts and the contact balls, the electric contacts and the contact balls are plated with gold. However, the complexity of processing by gold plating and the price are low. It had the problem of rising.

The present invention has been made in view of such problems of the prior art, and an object of the present invention is to detect a collision accident with reliability and reliability, and to have a simple structure and low cost. It is intended to provide a detector.

[0006]

[Means for Solving the Problems]

 In order to achieve the above object, the acceleration / deceleration detector according to the present invention moves in a cylindrical hollow portion inside the casing under acceleration or deceleration in a casing having a non-magnetic cylindrical hollow portion. A holding plate made of a magnetic material for enclosing a detection body made of a cylindrical magnet for acceleration / deceleration detection that can hold this detection body at a predetermined position at one end of the hollow part inside the housing in a steady state. When the detector receives acceleration or deceleration in the specified direction at the other end of the hollow casing, and the detector moves from the steady position by a predetermined distance, A reed switch that closes the contacts in response to magnetism is arranged, and in order to ensure the operation of this reed switch, a magnetic flux focusing pole is installed close to the reed switch.

The holding plate made of a magnetic material for holding the detection body made of the cylindrical magnet at a predetermined position in a steady state is made of a magnet for strengthening the holding force. Preferably.

Further, in order to ensure the operation of the reed switch, the magnetic flux focusing pole may be formed of a magnet having a weak magnetism in a range in which the magnetic field of the magnetic flux focusing pole does not activate the reed switch.

Further, the holding plate of the detection body and the magnetic flux converging pole may both be composed of magnets.

Further, the detection body made of the cylindrical magnet may be a detection body made of a spherical magnet.

[0011]

[Action]

 When the acceleration / deceleration detector of the present invention is used as a collision detector for automobiles, etc., the detector is composed of a magnet that moves by detecting acceleration / deceleration, which is enclosed in the hollow part of the detector housing. Align the moving direction of the vehicle with the forward direction of the vehicle such as an automobile, set the detector in the steady state to the rear side, and set the reed switch that detects deceleration to the forward side. Fixed to the vehicle.

[0012]

【Example】

 Examples will be described with reference to the drawings. In FIG. 1, the detector has a cylindrical hollow portion in an enclosure 1 made of a synthetic resin material or the like, and the hollow hollow portion is a detection body made of a cylindrical magnet that moves by detecting deceleration. 2 is enclosed.

One end (the left end in FIG. 1) of the hollow portion of the casing 1 is made of a magnetic material (for example, soft iron) for holding the detection body 2 in a predetermined position in a steady state where no impact is applied. A holding plate 3 is fixed to the housing 1. Therefore, in a steady state, the detection body 2 is attracted to the holding plate 3 by its attractive magnetic force, and this is at the base position.

On the other hand, at the other end (right end in FIG. 1) of the hollow portion of the casing 1, a glass tube vacuum sealed reed switch 4 for displacing a normally open contact point to a closed state by magnetic force is installed. It

Further, in order to prevent chattering of the contacts during operation of the reed switch 4 and to realize a reliable contact contact state, the magnetic flux concentrating poles 5 and 6 made of a magnetic material (for example, soft iron) are used for the reed switches. The reed switch 4 is placed close to the switch 4 via a spacer 7 at a position sandwiching the reed switch 4 from both sides as shown in FIGS. The two magnetic flux converging poles 5 and 6 are for ensuring that the magnetic field lines of the detection body 2 made of a magnet are concentrated on the reed contact surface of the lead switch 4 so that the reed switch 4 contacts are closed. is there.

Further, the outside of the magnetic focusing pole 6 is made of a non-magnetic synthetic resin material or the like for preventing the reed switch 4 from malfunctioning when a magnet is brought close to the detector from the outside. The formed lid 8 is fixed to the casing 1.

Further, as shown in FIG. 3, the holding force of the detection body 2 is strengthened by forming the holding plate 3 for holding the detection body 2 made of the magnet at the base position in the steady state with a magnet. Therefore, in order to prevent the detection body 2 from separating from the holding plate 3 at the time of sudden braking that is rarely encountered during normal driving of a vehicle such as an automobile, a large-sized detection body 2 having a strong magnetism is provided. Therefore, it is possible to realize the small and compact detector.

Further, either one of the two magnetic flux converging poles 5 and 6 (FIG. 4), or both of them (FIG. 5), which are installed in order to obtain a reliable closed state of the contact of the reed switch 4. If the reed switch 4 is composed of a magnet having a weak magnetic force in the range where the contact is not closed, the detection body 2 can be further downsized.

Further, as shown in FIG. 6, either one or both of the holding plate 3 and the magnetic flux converging poles 5 and 6 may be made of a magnet.

Further, the detection body 2 made of the cylindrical magnet may be configured as a detection body 9 made of a spherical magnet as shown in FIG.

[0021]

[Effect of the device]

 Since the present invention is configured as described above, it has the following effects.

In the acceleration / deceleration detector of claim 1, since the acceleration / deceleration is detected by the movement of the detection body by a magnet due to the inertial force and the reed switch that closes the contact in response to the magnetic force of the detection body, the mechanism is used. A simple and highly reliable detector can be realized.

In the acceleration / deceleration detector of claim 2, since the holding force of the detection body made of a magnet in the steady state at the base position is enhanced by using the holding plate as a magnet, the detector is miniaturized. It will be possible.

In the acceleration / deceleration detector according to claim 3, the reed switch can be operated only by the magnetism having one or both of the magnetic flux focusing poles for ensuring the operation of the reed switch. By using a magnet with weak magnetism in the non-existent range, it is possible to perform reliable detection using a smaller detector.

In the acceleration / deceleration detector of the fourth aspect, either one or both of the holding plate at the base position of the detection body and the two magnetic flux focusing poles for ensuring the operation of the reed switch, Since both are composed of magnets, it is possible to provide a compact and highly reliable detector.

In the acceleration / deceleration detector according to the fifth aspect of the present invention, by making the detection body spherical, the inertial force is detected and the movement state of the detection body becomes smoother, and high reliability can be obtained. it can.

[Brief description of drawings]

FIG. 1 is a sectional view of an essential part of an acceleration / deceleration detector.

FIG. 2 is a cross-sectional view of a main part of a relationship between a reed switch and both magnetic flux focusing poles.

FIG. 3 is a sectional view of an essential part of an acceleration / deceleration detector in which a holding plate is made of a magnet.

FIG. 4 is a sectional view of an essential part of an acceleration / deceleration detector in which one of the magnetic flux focusing poles is formed of a magnet.

FIG. 5 is a sectional view of an essential part of an acceleration / deceleration detector in which both magnetic flux focusing poles are magnets.

FIG. 6 is a sectional view of an essential part of an acceleration / deceleration detector in which one of a holding plate and a magnetic flux focusing pole is formed of a magnet.

FIG. 7 is a cross-sectional view of essential parts of an acceleration / deceleration detector in which a spherical magnet is used as a detection body.

[Explanation of symbols]

 1 Case 2 Detecting Body 3 Holding Plate 4 Reed Switch 5 Magnetic Flux Focusing Pole 6 Magnetic Flux Focusing Pole 7 Spacer 8 Lid 9 Sphere-shaped Detecting Body

Claims (5)

[Scope of utility model registration request] 1. A casing (1) having a non-magnetic cylindrical hollow portion can be moved in the casing (1) having the cylindrical hollow portion under acceleration or deceleration. Detecting body consisting of a cylindrical magnet for acceleration / deceleration detection (2)
And a holding plate (3) made of a magnetic material for holding the detection body (2) in a steady state at a predetermined position (left end position in FIG. 1) at one end of the hollow portion inside the housing (1). This detector is installed at the other end (the right end position in FIG. 1) of the hollow part inside the housing (1), and the detector is subjected to acceleration or deceleration in a designated direction, and the detector (2) A reed switch (4) for closing the contact in response to the magnetism of the detection body (2) when the reed switch has moved a predetermined distance from the predetermined position, and for ensuring the operation of the reed switch (4), Acceleration / deceleration characterized in that a magnetic flux focusing pole (5) composed of a magnetic material and a magnetic focusing pole (6) are installed at positions close to the reed switch (4) and sandwiching the reed switch (4) from both sides. Detector. 2. The acceleration / deceleration according to claim 1, wherein the holding plate (3) for holding the detection body (2) made of the magnet at a predetermined position in the hollow portion of the housing (1) in a steady state is a magnet. Detector. 3. Only one of the magnetic flux converging poles (5) and (6) installed near the reed switch (4) or both magnetic flux concentrating poles have only the magnetism.
The acceleration / deceleration detector according to claim 1, wherein the reed switch (4) is a magnet having a weak magnetism in a range in which it does not operate. 4. The acceleration / deceleration detector according to claim 1, wherein a holding plate (3) for holding the detection body (2) at a predetermined position at one end of a hollow portion inside the housing (1) in a steady state. )
Is composed of a magnet as described in claim 2, and the detector is subjected to acceleration and deceleration in a specified direction, the detector (2) moves a predetermined distance from the predetermined position, and the reed switch ( The both magnetic focusing poles (5) and (6) are provided for ensuring the operation of the reed switch (4) when 4) operates in response to the magnetism of the detection body (2). An acceleration / deceleration detector characterized by being configured by a magnet as described in 3. 5. The acceleration / deceleration detector according to claim 1, wherein the detection body (2) made of the cylindrical magnet is replaced with a detection body (8) made of a spherical magnet. 3. The acceleration / deceleration detector according to 3 or 4.