JPH02309258A - Acceleration sensor - Google Patents

Abstract

PURPOSE:To perform positioning and fixing by a terminal pin and to enhance the reliability of assembling by integrating a holder. CONSTITUTION:Stoppers 12, 12 ' present that the vibration of a leaf spring 10 having a magnetic body 11 also used as a weight at the leading end thereof becomes excessive. Two stoppers 12, 12 ' are integrally molded from a resin to form a holder 13 supporting magnetoresistance elements 18, 18 ' and a part thereof is extended to provide a leaf spring support part 14 and the root part of the leaf spring 10 is formed to the leaf spring support part by insert molding to be unified with the holder 13. A plurality of positioning and fixing holes 15 are formed to the holder 13 and the terminal pins 17 of a hermetic seal base 16 are inserted in the holes 15 to position the holder 13 and the pins are bent or a resin is used to fix the holder 13. By unifying the holder 13 and the leaf spring 10, the holder can be positioned and fixed without using a screw in the hermetic seal base 16.

Description

[Detailed Description of the Invention] [Summary] Regarding an acceleration sensor using a magnetoresistive element, for the purpose of facilitating assembly and improving reliability, a plate spring having a magnetic material at the tip and a displacement sensor of the magnetic material are used. a detecting magnetoresistive element;
In an acceleration sensor equipped with a resin holder that supports the magnetoresistive element and also serves as a stopper for the leaf spring, a part of the holder is extended, and a root portion of the leaf spring is insert molded in the core part. Constructed to have an integral structure.

[Industrial application field]

The present invention relates to an acceleration sensor using a magnetoresistive element.

Acceleration sensors are used in automobile suspension control, brake control, etc., and are required to be small, lightweight, and inexpensive.

[Conventional technology]

FIG. 4 is a diagram showing an acceleration sensor previously proposed by the present inventors (Japanese Patent Application No. 1-28083). In the same figure, 1
2 is the base of the hermetic seal which also functions as a magnetic circuit and magnetic shield, 2 is its cap, and 3 is a magnetic plate spring having a weight 4 at its tip, the base of which is fixed to the base 1 via two permanent magnets 5. ing. Further, 6 is a magnetoresistive element arranged on the left and right sides near the tip of the magnetic leaf spring 3.
It is fixed to the base 1 via a holder 7 which also serves as a stopper for the magnetic leaf spring. Changes in the magnetic field leaking from the tip of the magnetic leaf spring 3 that vibrates in response to acceleration are detected by the magnetoresistive element 6, and the magnitude of the acceleration can be measured from this detected value.

[Problem to be solved by the invention]

In the above acceleration sensor, it is necessary to glue or screw the leaf spring 3 and holder 7 to the base 1, but in either case, the leaf spring and the two holders must be glued or screwed separately. This always requires a lot of man-hours, and when using adhesives, the bonding positions of the parts may shift, and when using screws, the screws may not be tightened properly.

SUMMARY OF THE INVENTION In view of the above conventional problems, it is an object of the present invention to provide an acceleration sensor that is easy to assemble and is reliable.

[Means to solve the problem]

In order to achieve the above object, the acceleration sensor of the present invention includes a leaf spring 10 having a magnetic body 11 at its tip, and a plate spring 10 having a magnetic body 11 at its tip.
1, and a resin holder 13 that supports the magnetoresistive element and also serves as a stopper for the leaf spring 10. The leaf spring 10 is characterized in that the leaf spring 10 is extended and the root part of the leaf spring 10 is insert molded into the core part to form an integral structure.

[For production]

By insert molding the base of the leaf spring 10 into the resin holder 13 and integrating it with the two stoppers 12 and 12', it can be fixed to the base 16 with the terminal pin 17 of the hermetic seal base 16, and assembly is easy. becomes easier. Furthermore, reliability is improved because no adhesive or screwing is required.

〔Example〕

1 and 2 are views showing an embodiment of the present invention, with FIG. 1 being an assembled perspective view and FIG. 2 being an exploded perspective view of the main parts.

In FIGS. 1 and 2, reference numeral 10 is a leaf spring having a magnetic body 11 which also serves as a weight at the tip, and 12 and 12' are stoppers that prevent the amplitude of the leaf spring from becoming excessive. In this embodiment, these two stoppers 12 and 12' are integrally molded with resin to form a holder 13 that supports the magnetic resistance element, and a part of the holder 13 is extended to provide a leaf spring support part 14.
The root part of the leaf spring 10 is insert molded into the chain leaf spring support part and integrated with the holder 13. Also, the holder 1
A plurality of holes 15 for fixing before positioning are formed in 3, and the holes 15 are inserted into the terminal pins 17 of the hermetic seal base 16 for positioning, and the terminal pins 17 are fixed by bending the pins or using resin. The magnetoresistive elements 18 and 18' are mounted on an insulated or printed wiring board 19 as shown in FIG.
It is fixed by soldering. Then the magnetoresistive element 18.1
After wire bonding is performed between the electrode 8' and the terminal pin 17 or the printed wiring section, the cap 20 is sealed in the hermetic seal base 16.

In this embodiment configured in this way, when acceleration is applied in the direction of the arrow AA', the leaf spring 10 bends and the magnetic body 11
is displaced and the magnetic field applied to the magnetoresistive element 18.18' changes, thereby changing the electrical resistance of the magnetoresistive element 18.18'. This allows acceleration to be detected.

According to this embodiment, by integrating the holder 13 and the leaf spring 10, it is possible to position and fix the hermetic seal base 16 without using screws, so assembly is easy and there is no possibility of insufficient screw tightening. Reliability is also improved.

FIG. 3 is a diagram showing the main parts of the second embodiment of the present invention,
(a) is an exploded perspective view, and (b) is an assembled view. In this figure, the same parts as in FIGS. 1 and 2 are designated by the same reference numerals.

The difference between this embodiment and the previous embodiment is that the leaf spring 10 is not directly insert molded into the holder 13 as shown in Fig.
A letter-shaped metal fitting 21 is insert-molded into the leaf spring support portion of the holder 13, and the leaf spring 1 is attached to the metal fitting 21 as shown in Figure b.
3 is attached and fixed by spot welding or the like, and the rest is exactly the same as the previous embodiment. Therefore, the effect is also the same as that of the previous embodiment.

〔Effect of the invention〕

As explained above, according to the present invention, by integrating the holder, positioning and fixing using the terminal pin becomes possible, and assembly becomes easy. Furthermore, since screws, adhesives, etc. are not used, there are no screw tightening defects, poor positioning, etc., and the reliability of assembly is improved.

[Brief explanation of drawings]

Fig. 1 is a perspective view showing a first embodiment of the invention, Fig. 2 is an exploded perspective view showing main parts of the first embodiment of the invention, and Fig. 3 is a second embodiment of the invention. FIG. 4 is a diagram showing an example of a conventional acceleration sensor. In the figure, 10 is a leaf spring, 11 is a magnetic body, 12.12' is a stopper, 13 is a holder, 14 is a leaf spring support part, 15 is a hole for fixing before positioning, 16 is a hermetic seal base, 17 is a terminal pin, 18 and 18' are magnetoresistive elements, 19 is an insulating substrate, 20 is a cap, and 21 is an L-shaped fitting. Perspective view showing the first embodiment of the present invention Fig. 1 15... Fixing hole Fig. 2 Exploded perspective view showing main parts of the first embodiment of the present invention 17... Terminal pin (Q) FIG. 3 shows the main parts of the second embodiment of the present invention. FIG. 15 shows a hole for fixing before positioning. FIG. 4 shows an example of a conventional acceleration sensor.

Claims (1)

[Claims] 1. a leaf spring (10) having a magnetic material (11) at its tip;
A magnetoresistive element (18) detects the displacement of the magnetic body (11).
, 18') and a resin holder (13) that supports the magnetoresistive element and also serves as a stopper for the leaf spring (10), wherein the holder (13)
An acceleration sensor characterized in that a part of the leaf spring (10) is extended, and the root part of the leaf spring (10) is insert-molded into the extended part to form an integral structure.