JPH04235324A - Pressure sensor - Google Patents

Abstract

PURPOSE:To improve durability by providing step parts at the end parts of a cylinder having a cylindrical deformed part, bonding amorphous magnetic alloy at a part held with the step parts, and forming the shape of each step part in a double step shape or a tapered shape. CONSTITUTION:Pressure is transmitted into a pressure chamber 3 through a pressure introducing port 2. Stress is applied in the direction where the pressure chamber 3 is expanded. As a result, a deformed part 4 is fluctuated, and the permeability of amorphous magnetic alloy 8 which is bonded on the surface is changed. The change in permeability is detected as the change in inductance of a pressure detecting coil 9. The change in pressure is measured based on the differential output with a differential coil 10. The end parts of step parts 7 of a cylindrical main body 1 to which the alloy is bonded are made to be a double step shape or a tapered shape. Thus the durability can be improved.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure sensor using the magnetostrictive effect of an amorphous magnetic alloy.

0002

2. Description of the Related Art In recent years, pressure sensors using the magnetostrictive effect of amorphous magnetic alloys have been proposed. FIG. 2 is a cross-sectional view schematically showing an example of such a pressure sensor. 1 is a cylindrical main body made of titanium with a diameter of 10 mm and a height of 70 mm, 2 is a pressure introduction port with a diameter of 6 mm, and 3 is a pressure chamber for transmitting pressure. Reference numeral 4 denotes a cylindrical deformation part due to pressure, and a part of the main body 1 is processed to have a wall thickness of 2 mm. Reference numeral 5 indicates a non-deformable portion which is prevented from being strained by pressure. The inside of the non-deformable portion 5 has a hollow portion 6 of the same size as the pressure chamber 3. Deformed part 4
A step 7 having a height of 0.2 mm is provided at each end of the non-deformable portion 5. 8 is the deformed portion 4 on the outer periphery of the main body 1
25 with imide adhesive so as to cover the non-deformed part 5.
Fe-Si with a thickness of 0.03mm fixed in 1 hour at 0℃
-B-Cr-based amorphous magnetic alloy. 9 is a pressure detection coil formed by winding the coil 100 times; 10 is a differential coil having the same configuration as the pressure detection coil 9; A bobbin 11 made of phenolic resin is disposed on the outside of the magnetic alloy 8. 12 is a yoke made of 48% Ni-Fe alloy, and bobbin 11
attached to the outer periphery of the Reference numeral 13 denotes a fixing screw portion of the main body 1, which is machined to a pitch of PF3/8. 14 is a detection circuit.

[0003] Pressure is transmitted from the pressure introduction port 2 to the pressure chamber 3, and applies stress in a direction that causes the pressure chamber 3 to expand. As a result, the deformed portion 4 changes, and the magnetic permeability of the amorphous magnetic alloy 8 bonded to its surface changes. This change in magnetic permeability is detected as a change in inductance by the pressure detection coil 9, and the change in pressure is obtained from the differential output with the differential coil 10.

0004

[Problems to be Solved by the Invention] Since the amorphous magnetic alloy of the pressure sensor having the above-mentioned structure has a shape as shown in FIG.
1. As a result of subjecting this pressure sensor to a thermal test at -40° C. and 150° C., a claw-like peeled portion 22 was generated at the end of the seam 21, and the durability of the pressure sensor was deteriorated. This is because the adhesive accumulates at the stepped portion, and stress from cold and heat is concentrated there.

[0005] From the above, the structure of the pressure sensor has a problem of poor durability.

[0006]

[Means for Solving the Problems] In order to solve the above-mentioned problems, the present invention has a structure in which the shape of the stepped portion is at least two steps or a tapered shape, or a structure in which an amorphous magnetic alloy covers the entire cylinder. This is what I did.

[0007]

[Function] According to the above-mentioned configuration in which the step shape is at least two steps or tapered, the amount of adhesive that accumulates in the step portion is reduced, and the structure in which the amorphous magnetic alloy covers the entire cylinder For example, since there are no seams, durability can be improved in either case.

[0008]

Embodiment (Embodiment 1) An embodiment of the present invention will be described below with reference to FIG. 1(A). It should be noted that the detailed explanation of the configuration of the present invention that is the same as that of the conventional example will be omitted, and only the features of the present invention will be explained.

[0009] That is, the feature of the present invention is (FIG. 1(A))
The shape of the step 7 is made into a two-step shape, and the height thereof is set to 0.1 mm and 0.2 mm from the inside. An amorphous magnetic alloy 8 is adhered to the main body 1 having such a step 7.
When we conducted thermal tests at 40°C and 150°C, (Fig. 4
) No peeled areas were observed.

[0010] With the above configuration and operation, it was possible to obtain a pressure sensor with better durability than conventional pressure sensors.

In this embodiment, the number of steps was two, but similar results could be obtained even if the number of steps was two or more.

(Embodiment 2) A second embodiment of the present invention will be described below with reference to FIG. 1(B). It should be noted that the detailed explanation of the configuration of the present invention that is the same as that of the conventional example will be omitted, and only the features of the present invention will be explained.

[0013] That is, the features of the present invention are (FIG. 1(B))
The step 7 has a tapered shape with a width of 1 mm. When an amorphous magnetic alloy 8 was bonded to the main body 1 having such a step 7 and subjected to a thermal test at -40°C and 150°C, similar to the first example, peeling as shown in (Fig. 4) was observed. Part was not accepted.

[0014] According to this configuration, since there is almost no portion where excess adhesive accumulates compared to the first embodiment, durability is further improved.

[0015] With the above-described configuration and operation, it was possible to obtain a pressure sensor with better durability than conventional pressure sensors.

(Embodiment 3) A third embodiment of the present invention will be described below with reference to (FIG. 1(C)) and (FIG. 2). It should be noted that the detailed explanation of the configuration of the present invention that is the same as that of the conventional example will be omitted, and only the features of the present invention will be explained.

That is, the feature of the present invention is that the length in the circumferential direction of the amorphous magnetic alloy 8 in FIG.
The length in the circumferential direction is made equal to the length in the circumferential direction, and the shape is as shown in FIG. 1(C). As a result, when the amorphous magnetic alloy 8 is bonded to the deformed portion 4 and the non-deformed portion 5,
There is no seam as shown in FIG. 4, and the entire cylinder is covered with the amorphous magnetic alloy 8.

[0018] The pressure sensor of this configuration was tested at -40°C and 150°C.
Similar to the first example, no peeled portions as shown in FIG. 4 were observed.

Note that this configuration has the advantage that the same effects as in the first and second embodiments can be obtained without complicating the shape of the main body.

With the above configuration and operation, it was possible to obtain a pressure sensor with better durability than conventional pressure sensors.

[0021]

Effects of the Invention As is clear from the above description, according to the present invention, the shape of the stepped portion is at least two steps or tapered, or the amorphous magnetic alloy covers the entire cylinder. By doing so, it is possible to reduce the amount of adhesive that accumulates in the step portion, or to eliminate the joint portion of the amorphous magnetic alloy, and it is possible to provide a pressure sensor with good durability.

[Brief explanation of the drawing]

FIG. 1 (A) is a sectional view of a pressure sensor according to a first embodiment of the present invention. (B) is a sectional view of a pressure sensor according to a second embodiment of the present invention. (C) is a perspective view showing the appearance of an amorphous magnetic alloy according to a third embodiment of the present invention.

FIG. 2 is a sectional view of a conventional pressure sensor.

FIG. 3 is a perspective view showing the appearance of a conventional amorphous magnetic alloy.

FIG. 4 is a perspective view of a peeled portion of a conventional pressure sensor.

[Explanation of symbols]

1 Main body 2 Pressure inlet 3 Pressure chamber 4　Deformed part 5. Non-deformed part 6 Hollow part 7 Steps 8 Amorphous magnetic alloy 9 Pressure detection coil 10 Differential coil 11 Bobbin 12 York 13 Fixing screw 14 Detection circuit 21 Seam 22 Peeling part

Claims (2)

[Claims] 1. A pressure introduction port, and a cylindrical deformable portion that is distorted by the pressure introduced from the pressure introduction port,
In a pressure sensor having a configuration in which a step is provided at an end of the cylinder and an amorphous magnetic alloy having magnetostriction is adhered to a portion sandwiched between the steps, the step has a shape of at least two steps or a tapered shape. A pressure sensor characterized by: 2. A pressure introduction port, and a cylindrical deformable portion that is distorted by the pressure introduced from the pressure introduction port,
A pressure sensor having a configuration in which an amorphous magnetic alloy having magnetostriction is adhered to the cylinder, wherein the amorphous magnetic alloy covers the entire cylinder.