JPS59111033A - Pressure sensor - Google Patents

Abstract

PURPOSE:To enhance the high speed response of a pressure sensor, by providing a groove which is formed so as to mutually connect the pervious orifices of a lid part while prevented from protruding to the outside of the bottomed groove provided to a soft magnetic body. CONSTITUTION:Pervious orifices 11a are mutually communicated to each other by a groove 11b which is in turn provided above the opening part of a jar shaped soft magnetic body 10 and formed so as not to be protruded to the outside therefrom. When pressure P is applied by this groove 11b, a pressure transmitting medium is at first transmitted to the groove 11b low in the influence of viscosity from the pervious orifices 11a and thereafter transmitted to the upper surface of an alloy plate 7 coming to a pressure detecting part. In this procedure, the speed of the pressure transmission in the groove part is drastically accerelated as compared with a conventional system wherein pressure is transmitted over the entire region between the pervious orifices.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a pressure sensor using the magnetostrictive effect of an amorphous magnetic alloy.

(Conventional structure and problems) In recent years, pressure sensors that use the magnetostrictive effect of amorphous magnetic alloys have been proposed, but it is desirable to achieve high-speed response by smoothly transmitting pressure to the pressure receiving part. It is rare.

Figure 1 shows a cross section of a pressure sensor using a current amorphous magnetic alloy, in which 1 is an amorphous magnetic alloy plate with magnetostrictive properties, 5 is a cylindrical container, 2 is a coil, 2a is the coil terminal. Reference numeral 3 denotes a brim of a soft magnetic material, and 4 a lid having a through hole 4a, which is fixed to the cylindrical container 5 by caulking. pressure P
is joined to the amorphous magnetic alloy plate 1 through the through hole 4a, and the boundary amorphous magnetic alloy plate 1 is connected to the opening 3a of the bottomed groove of the soft magnetic body 3, as shown in FIG. flexural deformation occurs at the surface, generating internal stress. At this time, if the inductance of the pressure sensor is measured through the coil terminal 2a, a pressure inductance conversion type pressure sensor can be obtained since the inductance changes depending on the pressure.

In a pressure sensor having such a configuration, when pressure P is applied, the pressure is transmitted through the through hole 4a, and then the pressure is
As shown in FIG. 3, a soft magnetic body 3 without through holes 4a
It is added to the upper surface 6 of the amorphous magnetic alloy plate 1 corresponding to the opening portion. At this time, the pressure transmission medium enters into the slight gap between the lid part 4 and the amorphous magnetic alloy plate 1. the result,
Since the pressure transmission medium has viscosity, it takes time for the pressure to be uniformly applied to the entire pressure-receiving deformation portion of the amorphous magnetic alloy plate 1. That is, such a configuration has a drawback that changes in inductance cannot follow changes in pressure at high speed.

(Objective of the Invention) The present invention solves the problem of low response due to the viscosity of the pressure transmission medium as described above, and provides a pressure sensor capable of high-speed response.

(Structure of the Invention) In order to achieve the above-mentioned object, the present invention connects the through holes of the lid part with each other, and extends the part of the expanded soft magnetic material corresponding to the bottomed groove part to the outside of the bottomed groove part. A groove is formed so that there is no groove.

(Explanation of Examples) FIG. 4 shows an embodiment of the invention.

7 is an amorphous magnetic alloy plate having magnetostrictive characteristics, 8 is a cylindrical container, 9 is a coil, and 9a is a coil terminal. Reference numeral 10 indicates a pot-swelling soft magnetic material, and reference numeral 11 indicates a lid portion having a through hole 11a.
1a are communicated with each other through grooves 11b.

The groove 11b is provided so as to be located above the opening of the soft magnetic pot 10, and is formed so as not to protrude outward from the opening.

When the groove 11b is provided in the lid part 11 in this way, when the pressure P is applied, the pressure transmission medium passes through the through hole 11a, and then the influence of viscosity is first reduced, as shown by the arrow in FIG. Pressure transmission to the groove 11b is completed. However, at this time, due to the viscosity of the pressure transmission medium, no pressure is applied to the entire upper surface of the amorphous magnetic alloy plate 7 corresponding to the opening of the soft magnetic body 10. After that, as shown by the arrow in Fig. 6, the pressure transmission medium uniformly transmits the pressure to the upper surface 12 of the amorphous magnetic alloy plate 7, which becomes the pressure detection part. Compared to the previous method where the pressure was transmitted between all parts through the holes while being affected by the viscosity of the pressure medium, the pressure transmission in the groove part is dramatically faster, so the pressure sensing part of the amorphous magnetic alloy as a whole, i.e. Pressure propagates at an extremely high speed in the portion corresponding to the opening of the brim-swollen soft magnetic material.

(Effects of the Invention) If the structure of the present invention is used, in a pressure inductance conversion type pressure sensor, the ability to follow changes in inductance to pressure can be greatly improved, and the pressure sensor can be used for high-precision control, which has been increasing in demand in recent years. It becomes possible to realize high-speed response of the sensor, and the effect is extremely large.

[Brief explanation of the drawing]

Figure 1 is a cross-sectional view of a conventional pressure sensor, Figure 2 is a diagram showing the strain state of the amorphous magnetic alloy when pressure is applied to the pressure sensor in Figure 1, and Figure 3 is the same as Figure 1. Figure 4 is a structural sectional view of the pressure sensor of the present invention, and Figure 5 is a diagram showing the movement of the pressure transmission medium when pressure is applied to the pressure sensor of Figure 4. Figure 6 shows the initial movement of the pressure transmission medium in the case of
FIG. 6 is a diagram showing the movement of the pressure transmission medium following FIG. 5 when pressure is applied to the pressure sensor shown in FIG. 7... Amorphous magnetic alloy plate, 8... Cylindrical container, 9...
- Coil, 10... Expanded brim soft magnetic material, 11... Lid portion, 11b... Pressure transmission groove, 12... Top surface of amorphous magnetic alloy plate.

Claims (1)

[Claims] A brim-swelling soft magnetic material consisting of an annular outer wall, a central cylinder, and an annular bottomed groove between the two, wherein the annular outer wall and the center cylinder have tips on the same plane, and a tip of the brim soft-magnetic material. an amorphous magnetic alloy plate having magnetostrictive properties provided to cover the central column, a cylindrical container holding the soft magnetic material, and a coil wound around the central cylinder; In contact with this, there is a lid part provided with a through hole for accommodating a pressure transmission medium in a portion facing the opening of the bottomed groove, the through holes are communicated with each other by a groove part, and the through hole and the groove part are connected to each other. is formed so as not to protrude outside the opening of the bottomed groove.