JPH01112125A - Strain detector - Google Patents

Abstract

PURPOSE:To preclude an irregularity in coating and the involution of an air bubble, to make the thickness of an adhesive uniform, and to improve the output characteristics and temperature characteristics by adhering a magnetic layer to a passive shaft with a filmy adhesive formed by impregnating a net type member with resin. CONSTITUTION:The magnetic layer 5(6) is adhered to the passive shaft 1 with the filmy adhesive 16 formed by impregnating the nonmagnetic net type member 17 with the epoxy resin 18. The filmy adhesive 16 is only arranged between the passive shaft 1 and magnetic layer 5(6) and need not be applied. Then neither an irregularity in coating nor the involution of an air bubble is caused. The net type member 17 serves as a spacer and the thickness of the adhesive 18 is held uniform. Then the transmission of stress from the passive shaft 1 to the magnetic layer 5(6) is improved and the detection sensitivity is improved. Further, the linearity of the temperature characteristics and output characteristics is improved.

Description

[Detailed description of the invention] [Industrial application field] This invention relates to a distortion detector.

[Conventional technology]

Figure 2 shows the configuration of a conventional strain detector, where 1 is a passive shaft consisting of a rotating shaft, 2 is the central axis of the passive shaft 1, and 3°4 is the passive shaft 1.
This is a bearing that rotatably supports the

First and second magnetic layers 5.6 made of a high magnetostrictive material, such as an amorphous high magnetostrictive material, are firmly fixed to the outer periphery of the passive shaft l.

The first magnetic layer 5 is formed in a plurality of elongated strips in a direction of +45 degrees with respect to the central axis 2, and the second magnetic layer 6 is formed in a plurality of strips in a direction of -45 degrees with respect to the central axis 2. Further, a cylindrical coil pobbin 7 is arranged coaxially with the passive shaft 1 on the outer periphery of each magnetic layer 5.6. First and second detection coils 8.9 are wound around the outer periphery of the coil bobbin 7, and each detection coil 8.9 is connected to a detection circuit (not shown).

In the above configuration, when torque is applied to the passive shaft 1 from the outside, a tensile force is generated in one of the magnetic layers 5, 6, and a compressive force is generated in the other, resulting in distortion. The magnetic permeability changes due to this strain, and the magnetic permeability changes in opposite directions depending on whether the tensile force is applied or the compressive force is applied. The detection coil 8.9 detects a change in magnetic permeability as a change in magnetic impedance, and the detection circuit receives the output of the detection coil 8.9 and outputs a detection voltage corresponding to the amount of strain on the passive shaft 1.

Figures 3(a) to 3(d) show the conventional method of forming a magnetic layer. First, as shown in figure al, an adhesive JO is applied to the back surface of the magnetic layer (magnetic material ribbon) 5.6, This magnetic layer 5°6 (
b) Wrap it around the passive shaft 1 and glue it as shown in the figure. Next, as shown in Figure (C), the entire magnetic layer 5.6 is pressurized by an autoclave method or a pressurizing method, and the magnetic layer is heated and cured in this pressurized state. In the autoclave method (c), as shown in the upper half of the figure, the outer periphery of the magnetic layer 5.6 is covered with a tube 11, the pressure inside the tube 11 is reduced by exhaust, and the differential pressure with atmospheric pressure is released. Pressurize layer 5.6. In addition, in the pressurization method, the outer side of the tube 11 is covered with a cover 12, and air is supplied into the cover 12 to raise the pressure above the total atmospheric pressure to create a magnetic layer of 5°6.
Apply full pressure. After the adhesive 10 is heated and cured in this pressurized state, the magnetic layer 5.6 is selectively removed by etching to obtain a chevron-shaped magnetic layer 5.6f as shown in FIG.

[Problem that the invention seeks to solve]

However, the conventional strain detector described above
:, $4 figure (phantom, squeegee (spatula) as shown in (b)
13, when applying the adhesive 10 to the magnetic layer 5.6, air bubbles 14 were drawn in or the thickness of the adhesive 10 was uneven. For this reason, FIG. 5(a).

As shown in (b), air bubbles 15 are generated by the reaction gas during heating and hardening, and the bonding area becomes smaller, causing the magnetic layer to become magnetic. The adhesive strength of layer 5.6 became weaker.

In addition, the stress propagation property was lowered and the sensitivity was lowered. In general, since the thickness of the adhesive 10 was not uniform, the linearity of temperature characteristics such as residual thermal stress and output characteristics deteriorated.

This invention has been made to solve the above-mentioned problems, and it is an object of the present invention to obtain a strain detector that can improve the adhesive strength and sensitivity of the magnetic layer, as well as improve the output characteristics and temperature characteristics. For all purposes.

[Means for solving problems]

The strain detector according to the present invention has a magnetic layer bonded to a passive shaft via a film adhesive made of a net-like member impregnated with resin.

[For production]

The magnetic layer according to the present invention is bonded to the passive shaft through a film-like adhesive metal made of a net-like member impregnated with resin,
Since the film adhesive is already in the form of a film, it can be simply placed between the passive TlIh & magnetic layer and does not need to be coated. Therefore, uneven coating and inclusion of air bubbles do not occur. In addition, the net-like member serves as a spacer, and the floating adhesive is maintained uniformly.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings. In this example, d:, xat as shown in FIG.
G-layers 5 and 6 are bonded to the passive layer 11 via a film adhesive 16.
+ ]. Film adhesive J6 is shown in Figure 1 (b
As shown in FIG. 1, a non-magnetic net-like member 17 is impregnated with an epoxy resin 8, and is in the form of a film in advance. Therefore, the film adhesive] 6 is replaced by the magnetic layer 5.6.
The magnetic layer 5.6 is wound around the passive shaft 1 while being adhered to the passive shaft 1, and both are adhered to each other via the film adhesive 16. Thereafter, the entire magnetic layer 5 and 6 are subjected to IK pressure using an autoclave method or a pressure method as in the conventional method, and in this state, the film adhesive 16 is heated and hardened. Finally, the magnetic layer 5.6 is selectively removed by etching to form a chevron-shaped magnetic layer 5.6.

In this embodiment, since the adhesive 16 is already in the form of a film, it is sufficient to simply adhere it to the magnetic layer 5.6 and the passive shaft 1, and there is no need to apply it. Therefore, uneven coating and inclusion of air bubbles do not occur, and the adhesive strength and sensitivity increase due to the increased adhesive area. In addition, since the net-like member serves as a spacer, the thickness of the adhesive 10 is uniform (±5% or less).
This results in uniform output characteristics and temperature characteristics.

Note that if an epoxy resin or the like is applied to both the passive shaft 1 and the magnetic layer 5.6 (Zolaima treatment) before bonding the adhesive 16, the bonding can be performed smoothly. The reason why the net-like member 17 is made non-magnetic is that the magnetic flux generated by energizing the detection coil 8.9 flows through the adhesive 16, reducing the magnetic flux flowing to the magnetic layer 5.6, thereby reducing the sensitivity. This is to prevent it from decreasing.

6(a) to 6(c) show a second embodiment of the present invention, in which a recess 1a is formed around the adhesive portion of the magnetic layer 5.6 on the passive shaft 1, especially around the final adhesive portion. has been established. In this case, first, as shown in FIG. 6(a), the magnetic layer 5.6 is wound around the passive shaft l via the film adhesive 16, and the tube 11 is further arranged outside the magnetic layer 5.6. , a magnetic layer of 5.6 yt was pressurized by an autoclave method. When the entire heat curing process is performed in this state as shown in FIG. 6(b), the epoxy resin 18 of the adhesive 16, which has become fluid before being cured, flows into the recess 1a. The thickness t of the adhesive 16 is ensured by the net-like member 17). Next, as shown in FIG. 6(C), the portions 5a, 6a'f! of the magnetic layer 5.6 located above the recess 1a! : Removed by etching to obtain a chevron-shaped magnetic layer 5.6.

FIGS. 7(a) and 7(b) show two examples of the formation of the recesses 1a, and in FIG. In FIG. 7 6), it is provided in an annular shape only around the final bonded part.

This second embodiment is intended to compensate for the shortcomings of the first embodiment. In other words, in the first embodiment, as shown in FIG. Although the thickness of the adhesive 16 becomes thicker at the ends of 5 and 6, in this embodiment, the excess epoxy resin 18 flows into the recess 1a, so the uniformity of the thickness of the adhesive 16 is easily maintained. Ru.

〔Effect of the invention〕

As described above, according to the present invention, there is no need to apply adhesive to the magnetic layer, so uneven coating and air bubbles do not occur, and the adhesive area is large and the adhesive strength is high. Improved reliability.

Furthermore, the propagation of stress from the passive shaft to the magnetic layer is improved, and detection sensitivity is improved. Furthermore, since the net-like member in the adhesive acts as a spacer, the thickness of the adhesive is uniform, and the linearity of temperature characteristics such as residual thermal stress and output characteristics are improved.

[Brief explanation of the drawing]

FIGS. 1(a) and (b) are sectional views of essential parts of a strain detector and an explanatory diagram of a film adhesive in the first embodiment of the present invention, FIG. 2 is a sectional view of the strain detector, and FIG. (a) to (d) are explanatory diagrams of the conventional method of manufacturing a magnetic layer, and Fig. 4 (a)
, (bl is an f+ view and side view showing the conventional adhesive application state, FIGS. 5(a) and 5(b) are a front view and an enlarged view of part A of the conventional magnetic layer portion, and FIG. 6(a) )～(c)
79(a) and 79(b) are explanatory diagrams of the method of manufacturing the magnetic layer in the second embodiment of the present invention, and (bJ are explanatory diagrams of the state of formation of the recessed portion of the passive shaft in the embodiment of M2 of the present invention.1. ...Passive shaft, 1a...Recess, 5.6...Magnetic layer, 8°9...Detection coil, 16...Film-like adhesive, 17...Net-like member, 18... Epoxy resin. In addition, the same reference numerals in the drawings indicate the same or corresponding parts. Agent Masu Oiwa '9 Jl Bi

Claims (2)

[Claims] (1) A passive shaft that is subjected to stress, a magnetic layer with a high magnetostriction fixed on the outer periphery of the passive shaft, and a change in magnetic permeability due to strain in the magnetic layer that is arranged around the magnetic layer in response to the stress. What is claimed is: 1. A strain detector equipped with a detection coil for detecting , characterized in that a magnetic layer is adhered to a passive shaft via a film-like adhesive in which a net-like member is impregnated with resin. (2) The strain detector according to claim 1, wherein a recess is provided around the adhesive portion of the magnetic layer on the passive shaft.