JPH0540880U - Collision sensor - Google Patents

Abstract

(57) [Abstract] [Purpose] An object of the present invention is to provide a collision sensor which has a simple structure and can secure a necessary contact time between a sensing mass and a contact at the time of collision. In order to solve the above-mentioned object, a collision sensor of the present invention comprises a sensing mass 3 that detects a collision and moves,
A cylinder 4 that restrains the movement of the sensing mass 3 in one direction, a body 23 that holds the sensing mass 3 and the cylinder 4 and forms a front space 12 and a rear space 13 in front of and behind the cylinder 4, and is held by the body 23. In a collision sensor including a magnet 2 that attracts the sensing mass 3 to the rear space 13 side and a pair of contacts 5 that are located in the front space 12 and form a contact point with the sensing mass 3, At the contact part with the end, the body 2
3 is formed integrally with the sensing mass 3 and is provided with a projection 24 that is plastically deformed by contact with the sensing mass 3.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a collision sensor suitable for collision detection used in a trigger system of an airbag, which is a vehicle occupant protection device, and in particular, a collision with a sensing mass that moves against the bias force (suction force) of a magnet. Regarding those that detect.

[0002]

[Prior Art]

 Conventionally, as this type of collision sensor, those shown in FIGS. 4 and 5 are known. 4 is a sectional view, and FIG. 5 is a sectional view taken along line BB.

The detailed structure and operation of the collision sensor 1 will be described with reference to FIGS. 4 and 5. A sensing mass 3 that detects a collision and moves, a cylinder 4 that constrains the movement of the sensing mass 3 in one direction, a front space 12 and a rear space that hold the sensing mass 3 and the cylinder 4, and front and rear of the cylinder 4. 13, a magnet 6 that is held by the body 6 and that attracts the sensing mass 3 toward the rear space 13, and a pair of contacts 5 that are located in the front space 12 and that form a contact point with the sensing mass 3 (see FIG. 5). As shown, the cantilevered elastic pieces 5a and 5b are arranged so as to face each other). The body 6 has a diameter larger than that of the cylinder 4, and is formed by fitting a first body 6a for sealing one end surface of the cylinder 4 and a second body 6b for sealing the other end surface of the cylinder 4. The first body 6a is provided with a pair of arcuate guide surfaces 7 connected to the inner peripheral surface of the cylinder 4 on the left and right, and a tubular guide path 10 extending linearly by the guide surface 7 and the inner peripheral surface of the cylinder 4 is formed. Has been formed. Further, as shown in FIG. 5, a vertical groove 11 extending to the abutting surface of the cylinder 4 is provided on the outer peripheral portion between the pair of left and right guide surfaces 7 of the first body 6a. The seal 9 is for preventing air from flowing into the rear surface of the cylinder 4 through the gap between the cylinder 4 and the body 6.

Next, the operation of the collision sensor having such a structure will be described below. Normally, the sensing mass 3 is attracted by the magnet 2 and is positioned at the end of the rear space 13 and is in the state shown in the figure. When an impact is generated in the direction of the arrow in FIG. 4, the sensing mass 3 overcomes the attraction force of the magnet 2 and moves forward in the cylinder 4 while receiving the damping action of the air flow flowing through the gap with the cylinder 4 and the contact 5 It comes into contact with the cantilever elastic pieces 5a and 5b constituting the. A voltage is applied to the cantilever elastic pieces 5a, 5b by a battery 14 or the like, and the contact between the sensing mass 3 and the contact 5 causes the contacts to close and a current to flow, thereby activating the electric detonator 15 of the airbag device. ing. The sensitivity of the collision sensor having such a structure to the collision is determined by the magnetic intensity of the magnet 2, the gap between the sensing mass 3 and the cylinder 4, and the distance between the sensing mass 3 and the contact 5.

In addition, the current supply time for obtaining the necessary electric energy for operating the airbag device is such that the sensing mass 3 comes into contact with the contact 5 to close the contact, abuts against the end of the front space 12, and bounces back. Then, it is returned to the cylinder 4 by the attraction force of the magnet 2 again, and it is determined by the time until the sensing mass 3 separates from the contact 5 and the contact opens. That is, as the distance L between the contact point 5 and the end of the front space 12 is longer, the current supply time is longer and sufficient electric energy can be obtained.

However, this type of sensor is being made compact, and if the distance L is increased, the sensor becomes larger. Therefore, in FIG. 4, a cushioning material 8 is attached to the end of the front space 12 of the body, and the cushioning material 8 absorbs kinetic energy in the traveling direction of the sensing mass 3 to bring the cushioning material 8 into contact with the cushioning material 8 of the sensing mass 3. A collision sensor has been proposed in which the moving speed is decreased and the time until the sensing mass 3 comes into contact with the contact 5 and then moves away from the contact 5 is decreased by decreasing the speed of the sensing mass 3 (Japanese Patent Laid-Open No. 62-198764). reference).

[0007]

[Problems to be solved by the device]

 However, attaching the cushion material 8 requires that the cushion material 8 be manufactured separately from the body 6 and the cushion material 8 be inserted into a predetermined position of the body 6 and individualized. As a result, there is a problem in that the number of parts and the number of processing steps increase. In addition, there is a problem that, for example, a sun-positive material used as the cushion material 8 is likely to change with time and lacks reliability.

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 reduce the necessary contact time between the sensing mass and the contact at the time of collision with a simple structure. An attempt is made to provide a collision sensor that can be secured.

[0009]

[Means for Solving the Problems]

 In order to solve the above-mentioned object, a collision sensor of the present invention includes a sensing mass that detects a collision and moves, a cylinder that constrains the movement of the sensing mass in one direction, and a cylinder that holds the sensing mass and the cylinder. A collision that includes a body that forms a front space and a rear space in the front and rear, a magnet that is held by the body and that attracts the sensing mass to the rear space side, and a pair of contacts that are located in the front space and that form a contact with the sensing mass. In the sensor, a protrusion is formed at the contact portion between the sensing mass and the end of the front space, which is integrally molded with the body and causes plastic deformation by contact with the sensing mass.

[0010]

[Action]

 After the collision occurs, when the sensing mass comes into contact with the protrusion formed integrally with the body at the end of the front space of the body, the protrusion undergoes plastic deformation. Therefore, the kinetic energy in the traveling direction of the sensing mass is absorbed, and the returning speed of the sensing mass becomes slow.

[0011]

【Example】

 Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view of a collision sensor according to the present invention, FIG. 2 is a sectional view taken along the line AA of FIG. 1, and FIG. 1 and 2, parts having the same operations as those in FIGS. 4 and 5 are designated by the same reference numerals, and their description will be omitted. The difference between FIGS. 1 and 2 from FIGS. 4 and 5 is the shape of the body.

The first body 23 a of the body 23 includes a sensing mass 3 formed integrally with the body 23 a at a contact portion between the end of the front space 12 and the sensing mass 3 so as not to come into contact with the contact 5. Is provided with a projection 24 that causes plastic deformation by the contact. As shown in FIG. 2, the protrusions 24 have a conical shape and are provided at four locations so that the spherical surface of the ball-shaped sensing mass 3 is sandwiched. Since the first body 6a is a resin molded product made of resin such as nylon by injection molding, the protrusion 24 can be easily provided by partially changing the mold.

Next, the operation of the collision sensor 22 having the above-described configuration will be described with reference to FIG. Normally, the sensing mass 3 is attracted by the magnet and is located at the end of the rear space 13. When the collision occurs in the direction of the arrow, the sensing mass 3 overcomes the attractive force of the magnet and is advanced in the cylinder 4 while being attenuated by the air flow flowing through the gap between the sensing mass 3 and the cylinder 4, as shown in FIG. The cantilever elastic pieces 5a and 5b forming the contact 5 are contacted as shown in FIG. A voltage is applied to the cantilevered elastic pieces 5a, 5b by a battery or the like, and the contact between the sensing mass 3 and the contact 5 causes the contact to close and a current to flow, thereby activating the electric detonator of the airbag device. .

At this time, more than half of the sensing mass 3 is located in the first body. As a result, the gas compressed in the space in front of the sensing mass 3 passes through the groove 11 and flows into the space behind the sensing mass 3 from the large gap between the sensing mass 3. Therefore, the damping force of the sensing mass 3 due to the gas in the guide path 10 does not work. Therefore, the sensing mass 3 moves further forward. During this period, the cantilever elastic pieces 5a and 5b forming the contact 5 are deformed by the sensing mass 3, but their contact state is maintained.

When the sensing mass 3 moves further forward, the sensing mass 3 contacts the protrusion 24 as shown in FIG. 4B. As a result, the protrusion 24 is compressed, and plastic deformation begins while absorbing the kinetic energy of the sensing mass 3. Therefore, the forward moving speed of the sensing mass 3 is reduced. Even during this time, the contact state between the cantilevered elastic pieces 5a and 5b forming the contact 5 and the sensing mass 3 is maintained.

As shown in FIG. 4C, when the protrusion 24 is compressed to the maximum extent and is crushed, the sensing mass 3 receives a repulsive force by the end of the front space 12. However, the kinetic energy of the sensing mass 3 decreases with the plastic deformation of the protrusion 24, the coefficient of restitution is small, and the speed at which the sensing mass 3 is repelled is small.

In this way, the collision occurs with a simple structure in which the protrusion 24 formed integrally with the body 23a is provided at the contact portion between the end of the front space 12 and the sensing mass 3 so as not to contact the contact 5. The required contact time between the sensing mass and the contact can be secured.

In the above embodiment, four conical protrusions 24 are used, but the speed at which the sensing mass 3 bounces back can be adjusted by changing the number, shape, and size. For example, instead of the four conical projections, various projections are conceivable such as two wall-shaped projections having a square cross section arranged in parallel so as to sandwich a ball, or a cylindrical shape.

[0019]

[Effect of the device]

 Since the collision sensor of the present invention is provided with a protrusion integrally formed with the body that causes plastic deformation at the contact portion between the sensing mass and the end of the front space. , When the sensing mass comes into contact with the protrusion integrally formed with the body at the end of the front space of the body, the protrusion undergoes plastic deformation. Therefore, the kinetic energy in the traveling direction of the sensing mass is absorbed, the returning speed of the sensing mass becomes slower, and the necessary contact time between the sensing mass and the contact can be secured. In addition, since the protrusion is formed integrally with the body, the number of parts does not increase, and there is no need to perform a processing step of inserting and installing a cushion material. Moreover, since the protrusion is integrally molded with the body, only the protrusion does not change over time and deteriorate.

[Brief description of drawings]

FIG. 1 is a sectional view of a collision sensor of the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is an operation diagram of the collision sensor of the present invention.

FIG. 4 is a sectional view of a conventional collision sensor.

5 is a sectional view taken along line BB of FIG.

[Explanation of symbols]

 22 Collision sensor 2 Magnet 3 Sensing mass 4 Cylinder 5 Contact 23 Body 24 Protrusion

Front page continued (72) Hiroyuki Sada Inventor Hiroyuki Sada 2-11, Iwaya Minami-cho, Nada-ku, Kobe-shi, Hyogo (Sensor Technology Co., Ltd.) Inside Sensor Technology Co., Ltd. (72) Kozo Ota 2-11-11 Iwaya Minami-cho, Nada-ku, Kobe City, Hyogo Prefecture Inside Sensor Technology Co., Ltd.

Claims (1)

[Scope of utility model registration request] 1. A sensing mass that moves by sensing a collision, a cylinder that constrains the movement of the sensing mass in one direction, and a body that holds the sensing mass and the cylinder and forms a front space and a rear space in front of and behind the cylinder. , A collision sensor including a magnet held in the body for attracting the sensing mass toward the rear space and a pair of contacts that are located in the front space and form a contact point with the sensing mass. The collision sensor is characterized in that a protrusion integrally formed with the body and plastically deformed upon contact with the sensing mass is provided at the contact portion of the.