JPH0310137A - Pressure sensor - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

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. Although such a pressure sensor has been proposed, FIG. 4 is a sectional view showing an outline of an example of such a pressure sensor. 11 is a cylindrical body 1
2 is a pressure introduction port, and 13 is a pressure chamber for transmitting pressure.
14 is a deformed part obtained by processing a part of the main body 11 into a thinner part, 15
is a non-deformable part that is not strained by pressure. The non-deformable portion 15 has a hollow portion 16 having the same diameter as the pressure chamber 13 .

17 is an amorphous magnetic alloy bonded on the deformable portion 14 and non-deformable portion 15 on the outer periphery of the main body 11 & 18 is a pressure detection coil, which is an amorphous magnetic alloy bonded on the outer periphery of the deformable portion 14 It is arranged on the outside of the alloy 17 via a bobbin 19. 20 is a differential coil having the same configuration as the pressure detection coil 18, and is made of an amorphous magnetic alloy 1 bonded on the outer periphery of the non-deformable portion 15.
7 via a bobbin 19. 21 is a yaw attached to the outer circumference of the bobbin 19; 22 is a fixing screw portion of the main body 11; 23 is a detection circuit; a pressure is transmitted from the pressure inlet 12 to the pressure chamber 13, and is directed in a direction to inflate the pressure chamber 13; As a result of applying stress, the deformed portion 14 changes and the magnetic permeability of the amorphous magnetic alloy 17 bonded to its surface changes.This change in permeability is detected by the pressure detection coil 18 as a change in inductance. Problems to be Solved by the Invention Even if a change in pressure is obtained from the differential output with the coil 20 When measuring the pressure of a fluid with a pressure sensor having a conventional configuration, the fifth problem arises.
As shown in the figure, a bypass pipe 33 for attaching the pressure sensor 32 from the cylindrical pipe 31 is required, which takes up space, and furthermore, there are problems in that the mounting positions of the pressure sensor 32 and the bypass pipe 33 are limited. (Am) To provide a pressure sensor that can be installed at any position on a cylindrical pipe that transmits fluid without taking up much space when measuring fluid pressure.Means for solving the problem It has a configuration in which an amorphous magnetic alloy having magnetostriction is fixed to the amorphous magnetic alloy, and a magnetic permeability detection element is arranged to form a magnetic circuit around the outer periphery of the amorphous magnetic alloy. Due to the structure of the present invention, the amorphous magnetic alloy is directly fixed to the surface of the cylindrical pipe that transmits the fluid. It becomes possible to configure a sensor.

Embodiments Embodiment 1 FIG. 1 is a sectional view schematically showing a pressure sensor according to an embodiment of the present invention. ■ is a cylindrical pipe that transmits fluid,
The Fe-3i-B-Cr based amorphous magnetic alloy 2 is fixed to the surface using an epoxy adhesive for 250\2 hours. 3 is a pressure detection coil formed by winding a coil 100 times around a bobbin 4 made of tetrafluoroethylene disposed around the outer periphery of the amorphous magnetic alloy 2. Bobbin 4
A yoke 5 made of 45% Ni--Fe alloy is attached to the outer periphery of the pressure sensor.The operation of the pressure sensor of the present invention will be explained below.

When the pressure of the fluid flowing inside the cylindrical tube 1 changes, the surface of the cylindrical tube is subjected to stress in the direction of expansion or contraction. As a result, the amorphous magnetic alloy 2 fixed to the surface of the cylindrical tube 1 is strained. Due to this strain, the magnetic permeability of the amorphous magnetic alloy 2 changes due to the inverse magnetostriction effect. This change is detected as a change in inductance by the pressure detection coil 3, and pressure is obtained through the detection circuit 6. An example of the output of the pressure sensor of this embodiment is shown in FIG.

It can be seen from the figure that a good output with low hysteresis and good linearity can be obtained. In addition, since the space occupied by the bypass pipe and the pressure sensor body as shown in Figure 5 is not required, space can be saved.Furthermore, since the amorphous magnetic alloy can be fixed anywhere on the cylindrical pipe, the pressure sensor can be installed anywhere. In Example 1, the change in magnetic permeability of an amorphous magnetic alloy was detected using a coil. is shown in Figure 3 (a).

An amorphous magnetic alloy 2 is fixed to a part of the surface of the cylindrical tube 1.
It has a configuration in which a detection head 7 is disposed on the surface of the amorphous magnetic alloy 2 in the circumferential direction of the cylindrical tube l, and a differential head 8 is disposed in the axial direction. Figure 3 (B) shows the detection head 7 of Figure 3 (A).
By configuring it as shown in Figure 3 (A) when viewed from the A side, the head only needs to be applied to a part of the amorphous magnetic alloy, so the pressure is smaller than that of a coil. It is also possible to obtain a sensor by arranging the heads in the circumferential direction and the axial direction of the cylindrical tube with the head configuration shown in FIG. By taking the difference between the two, an output with good temperature characteristics can be obtained with high accuracy.

By the above configuration and operation, it is possible to obtain a pressure sensor that does not take up much space compared to the conventional one and can be installed at any location. By fixing the crystalline magnetic alloy,
Although it takes up a lot of space, it is possible to construct a pressure sensor that can be installed at any position in the cylindrical tube.

[Brief explanation of drawings]

Fig. 1 shows a cross-sectional diagram of a pressure sensor of the present invention. Fig. 2 shows the output characteristics of the same sensor. Fig. 3 shows a cross-sectional diagram of a pressure sensor configured using the head of the present invention. Fig. 4 shows a diagram of a conventional pressure sensor. Figure 5 is a side view of a pressure sensor with a conventional configuration attached to a cylindrical tube.
・・Amorphous magnetic joint 3, 18 ・・Pressure detection carp At,
4, 19... Bobbin, 5, 21... Yokyu 6
, 23... Detection circuit 7... Detection head, 8...
・Differential head, 11...Mainization 12...Pressure introduction μ 13...Pressure blockage 14...Deformation part, 15...
・Non-deformable part, 16...Hollow part, 20...Differential coil hoop 22...Fixing screw, 32...Pressure sensor, 33...Bypass

Claims (2)

[Claims] (1) An amorphous magnetic alloy having magnetostriction is fixed to a part of the surface of a cylindrical tube, and a magnetic permeability detection element is arranged around the outer periphery of the amorphous magnetic alloy to form a magnetic circuit. Features of pressure sensor. (2) A detection head and a differential head are disposed on the surface of a cylindrical tube as the magnetic permeability detection element, and pressure is detected from the inductance difference between the two types of heads as the fluid pressure changes. Pressure sensor described in .