JPH03108671A - Acceleration sensor - Google Patents

Abstract

PURPOSE:To attain excellent responsiveness and high reliability by a construction wherein a closed magnetic circuit is formed of a permanent magnet being movable inside a nonmagnetic container and of a magnetic yoke and a reed switch intersecting the direction of movement of the magnet and a contact is broken and made by the movement of the magnet due to acceleration. CONSTITUTION:A columnar permanent magnet 5 is accommodated in a nonmagnetic container 1 so that it is movable in the specified directions A1 and A2. Magnetic yokes 2a and 2b are fitted so that they intersect the directions of movement of the magnet, while a reed switch 6 is disposed in holes made in the lower end parts of the yokes, and a closed magnetic circuit is constructed of the magnet 5, the magnetic yokes 2a and 2b and the switch 6. When an impact acceleration of a set value or above is given in the forward A1 or backward A2 direction of the container 1, the magnet 5 moves to open the magnetic circuit and the switch 6 turns from a state of make to a broken one. When the impact acceleration vanishes, these are restored to the former positions. According to this constitution, the presence or absence of the impact acceleration of the set value or above can be known easily only by discriminating the broken and make states of the switch 6.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention is applicable to detecting the acceleration of moving objects such as automobiles, sensing the load capacity of elevators, etc., and detecting vibrations such as earthquakes. The present invention relates to an acceleration sensor.

(Prior Art) One of the conventional acceleration sensors is disclosed in Japanese Unexamined Patent Publication No. 61-50270, and its configuration is shown in FIG. 9.

This is because a colloidal magnetic fluid 11 made of ferrite (Fe304) or the like moves due to acceleration, and the amount of this movement is detected by the change in dielectric constant, that is, capacitance, of the capacitor 12, and the acceleration is output as a voltage value. It has become.

(Problem to be solved by the invention) However, since the above-mentioned conventional example outputs acceleration as a voltage value, it is necessary to extract an electrical signal by comparing it with the voltage value when no acceleration is applied. There is. Therefore, a logic circuit for difference and conversion is required to display it as acceleration, and since it is an indirect method of comparing with a reference value, it has the problem of poor responsiveness and low reliability.

An object of the present invention is to provide an acceleration sensor that has a simple configuration, has good responsiveness, and is highly reliable.

[Configuration of the Invention (Means for Solving the Problems)] In order to achieve the above object, the present invention provides an acceleration sensor including a movable permanent magnet and a non-magnetic container having a space in which the permanent magnet can move. , a magnetic yoke disposed in a direction intersecting the moving direction of the permanent magnet with respect to the container;
a reed switch, the permanent magnet, magnetic yoke, and reed switch form a closed magnetic path, and the contact of the reed switch is turned on and off by movement of the permanent magnet due to acceleration caused by impact or vibration. It's because I did it.

(Function) According to the above configuration, the contact is normally turned on by a closed magnetic path consisting of a permanent magnet, a magnetic yoke, and a reed switch, but when acceleration due to impact or vibration is applied, the contact is affected by the inertial force caused by them. When the permanent magnet moves, the contact turns off, and acceleration due to impact or vibration disappears, the permanent magnet returns to its original position due to magnetic attraction, and the contact returns to on.

With this mechanism, the on and off signals can be taken out directly, and the above problem can be solved.

(Example) The present invention will be described in detail below with reference to FIGS. 1 to 3.

FIG. 1 is a partially cutaway perspective view showing an embodiment of the present invention.

FIG. 2 is a side sectional view of the above embodiment.

FIG. 3 is an explanatory diagram of the operation of the embodiment device shown in FIG. 1.

As shown in each figure, this acceleration sensor includes a box-shaped non-magnetic container 1, a column-shaped permanent magnet 5 housed in the container 1,
A magnetic yoke 2a provided opposite to the side surface of this container 1
, 2b, and a reed switch 6 disposed below the pair of magnetic yokes.

The non-magnetic container 1 is provided with a space in which a columnar permanent magnet 5 can move, and the permanent magnet 5 moves inside the container 1 along A1.
Or it can move in the A2 direction.

The tips of the pair of magnetic yokes 2a and 2b face each other in a direction intersecting the moving direction A1 or A2 of the columnar permanent magnet 5,
The magnetic yokes 2a and 2b are attached so that their bent end faces face holes provided in the container 1.

The reed switch 6 disposed in the hole at the lower end of the pair of magnetic yokes 2a and 2b includes a glass tube, a lead 3a sealed in the glass tube, and a lead 3a whose both ends protrude outward.
3b. 8 is a contact point of the lead.

In this way, the columnar permanent magnet 5, the pair of magnetic yokes 2
a, 2b and the reed switch 6 constitute a closed magnetic path.

The non-magnetic container 1 is provided with a lid 7, and the columnar permanent magnet 5 is covered with the lid 7.

Next, the operation of the above embodiment will be explained with reference to FIG.

When an impact acceleration equal to or greater than a set value is applied to the front A2 or rear A1 direction of the container 1, the columnar permanent magnet 5 moves in the A1 or A2 direction due to the impact acceleration, and the position of the pair of magnetic yokes 2a and 2b is and moves to a position where it collides with the inner wall surface of the container 1 as shown by the imaginary line 5'.

Due to the movement of the permanent magnet 5, the permanent magnet 5 is removed from the position of the pair of magnetic yokes 2a and 2b, so that the initially configured closed magnetic path becomes an open magnetic path.

As mentioned above, it has a simple configuration consisting of a permanent magnet, a magnetic yoke, and a reed switch.Furthermore, for example, if the reed switch 6 is initially on, it will turn off when impact acceleration is applied, so if the reed switch is opened or With a simple mechanism that only determines the closed state, it is possible to easily determine whether an impact acceleration exceeding a set value has been applied.

Note that when the impact acceleration is no longer applied, the permanent magnet is attracted toward the magnetic yoke and returns to its original position.

Next, FIG. 4(a) is a perspective view showing another embodiment of the present invention.

The difference between the embodiment and the embodiment shown in FIG. 1 is that a spherical permanent magnet 10 is used instead of the columnar permanent magnet 5.
The point is that it is possible to move not only in the front-rear direction as shown in the figure, but also in all directions on the horizontal plane intersecting the magnetic yoke.

As shown in FIGS. 4(a) and 5(a), this acceleration sensor includes a non-magnetic container 9 consisting of a spherical permanent magnet 10, a receiving portion 9b and a lid 9a for housing the permanent magnet 10. ,
Magnetic yoke 2 provided opposite to the upper and lower surfaces of this container 9
a, 2b, and a reed switch 6 disposed between the other ends of the pair of magnetic yokes.

The non-magnetic container 9 has a space in which a spherical permanent magnet 10 can move, and the permanent magnet 10 moves inside the container 9 not only in the B1 or B2 direction and the C1 or C2 direction, but also in the horizontal plane. It is able to move in any direction.

One end of the pair of magnetic yokes 2a, 2b facing each other with the container 9 in between is attached to the container 9 in the same manner as shown in FIG.

A reed switch 6 is provided at the other end of the magnetic yokes 2a, 2b in a similar form to that shown in FIG.

In addition, a pair of magnetic yokes 2a and 2b of the spherical permanent magnet 10
In addition to the spherical surface shown in FIG. 5(a), the contact surface may be a partially cut-out flat surface 10a as shown in FIG. 5(b) to increase the magnetic attraction force. . .

Further, the receiving portion 9b of the permanent magnet 10 may have a dish-shaped concave portion 9d as shown in FIG. 6(a), in addition to the flat surface shown in FIG. 4, or as shown in FIG. 6(b). Concave surfaces may be provided on the top and bottom of the container 9. According to such a configuration,
The return operation of the permanent magnet 10 becomes easier.

Next, the operation of the above embodiment will be explained.

Initially, a spherical permanent magnet 10, a pair of magnetic yokes 2a,
2b and the reed switch 6 form a closed magnetic path.

When using a container 9b having a receiving portion with a flat moving surface for the permanent magnet 10 shown in FIG. 4(b), impact acceleration exceeding a set value is applied in all directions on the horizontal plane intersecting the magnetic yoke. Due to the impact acceleration, the spherical permanent magnet 10 is removed from the position of the pair of magnetic yokes 2a, 2b and moved to a position where it comes into contact with the side wall surface of the container 9.

Further, when a container 9C having a dish-shaped receiver portion for the permanent magnet 10 shown in FIGS. 6(a) and 6(b) is used, the same effect as described above is obtained.

Furthermore, a spherical permanent magnet has a smaller contact area with a pair of magnetic yokes and a smaller magnetic pole surface than a columnar one, so in the case of a spherical permanent magnet, a minute impact or vibration causes the permanent magnet to move. It is possible to move it to a position where it touches the side wall surface of the container.

According to such an embodiment, as in the embodiment shown in FIG. Therefore, it is also possible to detect vibrations such as earthquakes.

Note that by covering the spherical permanent magnet 10 with a magnetic fluid, the movement of the permanent magnet can be made smoother, the magnetic force can be increased, and the detection sensitivity can be increased.

Figure 7 shows an example of an acceleration sensor with the configuration shown in Figure 1 above designed for actual use.In the acceleration sensor with the configuration shown in Figure 4 above, the permanent magnet is spherical. A similar design can be achieved by replacing them.

FIG. 7(a) is a front sectional view, and FIG. 7(b) is a plan sectional view. In the actual usage example shown in this figure, the first
The drawing is upside down.

The non-magnetic container 1 is configured as a rectangular tube with flanges on the top and bottom, and the opening surface of the rectangular tube is sealed with a lid 7 while a columnar permanent magnet 5 is housed inside the rectangular tube. .

On the other hand, the reed switch 6 is made of a glass tube by molding the entire plate terminals Ta and Tb except the tips with resin M with the leads 3a and 3b at both ends connected to the plate terminals Ta and Tb for external extraction. It has a protective structure. With the reed switch thus molded placed horizontally on the upper flange of the container 1, the reed switch 6 is placed so that its tip faces both ends of the reed switch 6 and the other end faces the position where the permanent magnet 5 is placed. A pair of L-shaped magnetic yokes 2a
, 2b are attached. In the above-mentioned combined state, a U-shaped metal fitting P is attached from one side of the lower flange IB of the container 1 to the upper end of the resin molded part M and further to the other side of the lower flange IB of the container 1. The entire tightening is fixed. This fastening is performed using screws or the like that are attached through holes Pa provided at both ends of the metal fitting P and screw holes provided in the lower flange portion IB of the non-magnetic container 1.

In addition, by selecting the magnetic force of the magnetic path consisting of the permanent magnet, magnetic yoke, and reed switch, it is possible to adjust the detection sensitivity for detecting shock or vibration. Detection sensitivity and Responsiveness can be adjusted.

Also, as shown in FIG. 8, a magnetic yoke 2a.

2b may be placed on top of the reed switch 6.

In any of the above embodiments, a reed switch with a reed piece sealed in glass is used as a switch element, so a highly reliable device that is not affected by the surrounding environment and does not malfunction can be obtained. I can do it.

[Effects of the Invention] As described above, the present invention has a simple structure in which a magnetic path is formed by a permanent magnet, a magnetic yoke, and a reed switch. Since it has a mechanism that opens and closes, and direct on and off signals can be easily taken out, it is possible to provide an acceleration sensor with good responsiveness and high reliability.

[Brief explanation of drawings]

FIG. 1 is a partially cutaway perspective view showing one embodiment of the present invention, and FIG.
The figure is a side sectional view of the above embodiment, FIG. 3 is an explanatory diagram of the operation of the apparatus of the embodiment shown in FIG. 1, and FIGS. 4(a) and (b) are perspective views showing other embodiments of the present invention. and side sectional view, fifth
Figure (a) is an explanatory diagram of the operation of the apparatus according to the embodiment shown in Fig. 4, Figure (b) is a diagram showing a modification of the permanent magnet in the embodiment shown in Figure 4, b) is a side cross-sectional view showing the receiving part of the permanent magnet in the embodiment shown in FIG. 4, and FIGS. 7(a) and (b) are front views showing a specific embodiment of the embodiment shown in FIG. A sectional view and a plan sectional view, FIG. 8 is a diagram showing a modification of the configuration of a magnetic yoke and a reed switch, and FIG. 9 is a configuration diagram of a conventional acceleration sensor. 1... Container, 2a, 2b... Magnetic yoke, 3...
・Reed, 5, 10... Permanent magnet, 6... Reed switch, 7... Lid of movable container, 8... Contact of reed switch, 9... Two-tiered container, 11... Magnetic Fluid, 12... Capacitor. (G) 0 -45' -453- akoqko

Claims (3)

[Claims] (1) In an acceleration sensor, a movable permanent magnet, a non-magnetic container having a space in which the permanent magnet can move, and a magnetic yoke arranged in a direction intersecting the moving direction of the permanent magnet with respect to the container. and a reed switch, wherein the permanent magnet, the magnetic yoke, and the reed switch are arranged so as to form a closed magnetic path. (2) The acceleration sensor according to claim 1, wherein the movable permanent magnet is columnar. (3) The acceleration sensor according to claim 1, wherein the movable permanent magnet is spherical.