JPH06265572A - Acceleration detector provided with falling impact buffering function - Google Patents

Abstract

PURPOSE:To prevent damage by additionally providing the housing with a member for buffering impact thereby protecting the internal structure and components. CONSTITUTION:A buffering member 80 made of a silicon based resin, hard rubber, etc., is bonded through an adhesive or the like to three faces of a housing 10 except the opening face 11, the opposing face, and a face planted with fixing pins 70 and a detection terminal 21. When a lead switch 20 contained in the housing 10 is subjected to impact in the direction perpendicular to the longitudinal direction, the gap length between leads alters to vary the slow- operation ampere-turns and open ampere-turns, and thereby the buffer member 80 is applied to a plane extending perpendicularly to the longitudinal direction of the switch 20. The buffer member 80 is not applied to the plane planted with the pins 70 and the terminal 21 because it hinders the fixing of the detector to a circuit board. The buffer member 80 maybe applied to two planes in the axial direction of the housing 10.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an acceleration detector suitable for an auxiliary detector (generally called a safing sensor) used as an auxiliary to the main detector in an acceleration detecting device used for an airbag system of an automobile. Regarding
In particular, the present invention relates to an acceleration detector in which a cushioning member is arranged in a housing portion to cushion an impact force applied by dropping.

[0002]

7 and 8 are an exploded perspective view and a vertical sectional view showing an example of a conventional acceleration detector. 7 and 8, the acceleration detector has an annular shape with a casing 10 made of a relatively hard resin, and the casing 10 is provided in a gap between an inner cylinder portion 12 and an outer cylinder portion 13 of the casing 10. Of the permanent magnet 30 that is slidable in the axial direction, the coil spring 40 that is in contact with the permanent magnet 30 and that is disposed in the gap, and has an annular shape. The stopper 50 fixed to the step 131 on the inner wall of the
Reed switch 2 fixed by inserting 2 in the longitudinal direction
0 and a packing material 60 filled and solidified in the opening 11 of the housing 10. The permanent magnet 30 has a stopper 5
The coil spring 40 regulated to 0 urges the casing 10 toward the bottom of the cylinder. The detection terminals 21 at both ends of the reed switch 20 are led out from the notches following the opening 11 of the housing 10 and are erected on the lower surface in the drawing. Two mounting pins 70, which are press-fitted or insert-molded into the housing 10, are provided upright on the lower surface of the housing 10 in the drawing.

This acceleration detector is used by being mounted in an automobile or the like in a state in which the detection terminal 21 and the mounting pin 70 are assembled to a circuit board of the acceleration detection device by soldering or the like. When an acceleration of a predetermined value or more is applied to the permanent magnet 30 of the detector in the direction of the arrow a due to a collision accident of the automobile, the permanent magnet 30 moves in the direction of the arrow a, and the magnetic field causes the magnetic field to be read. The switch 20 operates to generate an ON signal or an OFF signal between the two detection terminals 21.

[0004]

The acceleration detector is
Since the housing 10 is made of a hard resin and has a relatively flat surface shape, if the housing 10 is dropped in the step of assembling to the circuit board or the like, an impact force is applied from the housing 10 to the inside thereof. Is added, the relative positional relationship between the two lead pieces of the reed switch 20 changes, which changes the moving ampere turn and the open ampere turn of the reed switch 20 to change the characteristics of the acceleration detector, for example, the operating time. There is a problem that it ends up.

An object of the present invention is to provide an acceleration detector capable of protecting the internal structure and parts by buffering the impact force applied to the housing.

[0006]

According to the present invention, a slidable permanent magnet and a reed switch fixed near the permanent magnet are provided in a housing, and the reed switch is In the acceleration detector that operates by the magnetic field of the permanent magnet that moves according to the applied acceleration, the housing has a buffer member that buffers the applied impact force. You get a bowl.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An acceleration detector with a drop shock absorbing function according to an embodiment of the present invention will be described below with reference to the drawings.

[First Embodiment] FIGS. 1 and 2 show a first embodiment.
3 is an exploded perspective view and a vertical sectional view of the acceleration detector according to FIG. In both figures, the same parts as those of the conventional example and the same parts are denoted by the same reference numerals as those in FIGS. 7 and 8 and will not be described in detail.

In FIG. 1 and FIG. 2, the acceleration detector of the present invention is similar to the above-mentioned conventional example in that the housing 10, the permanent magnets 30,
Coil spring 40, stopper 50, reed switch 20,
Having a packing material 60 and a mounting pin 70,
It is to detect that an acceleration of a predetermined value or more is applied in the direction of arrow a.

Further, a surface of the housing 10 having the opening portion 11,
The surface facing this surface, the mounting pin 70, and the detection terminal 2
A cushioning member 80 made of silicone resin, hard rubber or the like is fixed to each of the three surfaces other than the standing surface of No. 1 with an adhesive or the like.

Due to its structure, the reed switch 20 provided in the housing 10 is weak against an impact force in a direction perpendicular to its longitudinal direction. That is, when an impact force in a direction perpendicular to the longitudinal direction is applied, the gap length between the lead pieces changes, and the moving ampere-turn and open ampere-turn change. Therefore, in the first embodiment, the cushioning member 80 is provided on the extended surface in the direction perpendicular to the longitudinal direction of the reed switch 20. However, since the surfaces where the mounting pins 70 and the detection terminals 21 are erected are mounting surfaces to the circuit board, providing a cushioning member here will be an obstacle, and the pins and terminals may function as cushioning materials. Since it is considered that there is no need to newly provide a cushioning member on this surface, the cushioning member 80 is not provided on the standing surface of the pin or the terminal.

Further, the cushioning member 80 can be provided on the two surfaces of the housing 10 in the cylinder axis direction in addition to the above three surfaces. Further, in FIG. 1, the cushioning member 80 is provided near the center of each of the three surfaces of the housing 10, but may be provided along the ridgeline of the housing 10. By providing the cushioning member along the ridgeline, when the floor surface or the like where the detector falls is flat, only the cushioning member substantially collides with the floor surface, thereby cushioning the impact force. Effective above.

[Second Embodiment] FIGS. 3 and 4 show a second embodiment.
3 is an exploded perspective view and a vertical sectional view of the acceleration detector according to FIG. In the drawings, the same parts as those in the first embodiment and the same parts are designated by the same reference numerals as those in FIGS. 1 and 2 and will not be described in detail.

3 and 4, the present acceleration detector has a housing 10 having an internal structure similar to that of the first embodiment, and an acceleration of a predetermined value or more is applied in the direction of arrow a. Is to detect. In addition, the opening 1 of the housing 10
A cushioning member 90 made of silicone resin or hard rubber is fixed by an adhesive or the like to all of the three surfaces except the surface having No. Has been done. The cushioning member 90 is
As shown in the figure, it is also possible to cover the three surfaces by one piece, for example, by sharing the buffer member pieces corresponding to the respective three surfaces. In the second embodiment as well, similar to the first embodiment, the cushioning member can be provided on the two surfaces of the housing 10 in the cylinder axis direction.

[Third Embodiment] FIGS. 5 and 6 show a third embodiment.
3 is an exploded perspective view and a vertical sectional view of the acceleration detector according to FIG. In the drawings, the same parts as those in the first embodiment and the same parts are designated by the same reference numerals as those in FIGS. 1 and 2 and will not be described in detail.

5 and 6, the present acceleration detector has a housing 10 having the same internal structure as that of the first embodiment, and an acceleration of a predetermined value or more is applied in the direction of arrow a. Is to detect. In addition, the opening 1 of the housing 10
A cushioning portion 14 as a cushioning member is integrally formed on the housing 10 on each of the three surfaces except the surface having the number 1, the surface facing the surface, and the surface on which the mounting pin 70 and the detection terminal 21 are erected. . The shock-absorbing portion 14 is formed by a plurality of thin-walled projecting pieces having a partial annular cross section arranged in an array, and buffers the impact force by bending the thin-walled projecting pieces with respect to the applied impact force. Since the cushioning portion 14 is integrated with the housing 10, the material of the cushioning portion 14 should be selected in consideration of the elasticity required for the cushioning portion 14 and the strength required for the entire housing 10.

[0017]

The acceleration detector with a drop impact buffering function according to the present invention has a buffer member in its housing for buffering the impact force applied, so that the acceleration detector with a drop impact buffering function can be installed in a circuit board. In order to buffer the impact force with the buffer member,
The impact force transmitted from the casing to the inside can be reduced. Therefore, it is possible to protect the precision parts such as the reed switch inside the housing against the impact force, and also to protect the internal structure such as the positional relationship of each part and prevent the damage and the generation of defective products. Therefore, it is easy to use in the process of assembling into the device, and the yield of non-defective products is good.

Further, if the cushioning member is formed integrally with the housing, an acceleration detector with a drop impact cushioning function can be obtained without increasing the number of parts, and the economical efficiency in industrial mass production is improved.

[Brief description of drawings]

FIG. 1 is an exploded perspective view showing an acceleration detector with a drop shock buffering function according to a first embodiment of the present invention.

FIG. 2 is a vertical sectional view of the acceleration detector shown in FIG.

FIG. 3 is an exploded perspective view showing an acceleration detector with a drop shock absorbing function according to a second embodiment of the present invention.

FIG. 4 is a vertical sectional view of the acceleration detector shown in FIG.

FIG. 5 is an exploded perspective view showing an acceleration detector with a drop impact cushioning function according to a third embodiment of the present invention.

6 is a vertical cross-sectional view of the acceleration detector shown in FIG.

FIG. 7 is an exploded perspective view showing an acceleration detector according to a conventional example.

8 is a vertical sectional view of the acceleration detector shown in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Housing 11 Opening part 12 Inner cylinder part 13 Outer cylinder part 14 Buffer part 20 Reed switch 21 Detection terminal 30 Permanent magnet 40 Coil spring 50 Stopper 60 Packing agent 70 Mounting pin 80, 90 Buffer member

Claims (3)

[Claims] 1. A housing having a slidably arranged permanent magnet and a reed switch fixed near the permanent magnet, wherein the reed switch moves in accordance with an applied acceleration. In the acceleration detector that operates by the magnetic field of a permanent magnet, the housing has a cushioning member that cushions an applied impact force. 2. The buffer member is made of a material different from that of the housing, and is arranged on an outer wall surface of the housing parallel to the longitudinal direction of the reed switch. 2. The acceleration detector with a drop shock absorbing function according to claim 1, wherein the acceleration detector with a drop shock absorbing function is arranged over the entire surface excluding the surface on which the lead terminals of the reed switch are erected. 3. The acceleration detector with a drop shock absorbing function according to claim 1, wherein the cushioning member is made of the same material as the casing and is formed integrally with the casing.