JPH051958A - Dynamic quantity measuring device - Google Patents

Abstract

(57) [Abstract] [Purpose] Amorphous ribbon for torque detection is firmly fixed to the object to be measured to prevent the ribbon from peeling and to improve the detection accuracy. Further, it is possible to simplify the step of fixing the ribbon. [Structure] A thin strip 2 is fixed to a shaft 1 for transmitting torque by welding. The thin ribbon 2 is a soft magnetic film (for example, an amorphous alloy) whose magnetic permeability sharply decreases above the crystallization temperature.
Made with. Heating part 6 and 7 produced by the welding
Reduces the magnetic permeability of that portion while integrating the ribbon 2 and the shaft 1. A coil (not shown) is arranged to face the heating portion 7, and the inductance change of the coil causes
The strain of the ribbon 2 or the torque transmitted to the shaft 1 is measured.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mechanical quantity measuring device,
In particular, the present invention relates to a mechanical quantity measuring device that measures the force or torque that has caused the strain based on the magnetic characteristics of the detection film that changes corresponding to the strain that occurs in the object.

[0002]

2. Description of the Related Art When a ribbon of amorphous alloy (hereinafter referred to as "amorphous") is bonded to an object and a mechanical quantity such as pressure or torque is applied to the object, the ribbon is deformed together with the object. Then, it is known that the amorphous magnetic properties change according to the generated strain. Therefore, if the change in the magnetic characteristics is detected, it is possible to measure the mechanical quantity such as the pressure or torque that has caused the strain based on the result. As a measuring device utilizing such a principle, for example, JP-A-63-69283 and JP-A-62-69283 can be used.
There is an apparatus described in Japanese Patent No. 159002.

FIG. 4 is a perspective view showing a main part of the conventional device. In the figure, a mechanical quantity (here, torque T) to be measured is added to the axis 1. The shaft 1 is made of an amorphous alloy, such as Metgl manufactured by Allied.
A thin strip 2 made of as 2605sc (trade name) is wrapped around,
It is bonded with a thermosetting resin adhesive. The thin strip 2 is formed with two rows of slits 5 arranged in the circumferential direction at a predetermined angle from the center line of the shaft 1. The slits 5 are formed in the ribbon 2 by etching, and the directions of inclination of the two rows of slits with respect to the center line of the shaft 1 are opposite to each other. Then, around the shaft 1 around which the ribbon 2 is wound, the detection coils 3 and 4 are provided.
Are arranged.

With this structure, the torque T is applied to the shaft 1.
Is transmitted, the shaft 1 is twisted and the ribbon 2 is distorted. In particular, stress is concentrated on the slits 5, and the strain of the ribbon 2 becomes significant between the slits 5. When the thin ribbon 2 is distorted, its magnetic characteristics change and its magnetic permeability decreases. Therefore, if the magnetic permeability of the ribbon 2 decreases, the inductance of the detection coils 3 and 4 also decreases. The relationship between the magnitude of this inductance and the torque can be experimentally obtained in advance, and the torque generated in the shaft 1 can be obtained according to this relationship. Since the detection coils 3 and 4 are arranged corresponding to the two rows of slits 5 having different angles with respect to the axis 1, the change in inductance is detected differentially.

[0005]

The conventional measuring device described above has the following problems. First, in terms of quality, since the thin strip 2 is fixed to the shaft 1 with an adhesive, there is a problem in that reliability against peeling is low when repeatedly used. Further, since the mechanical quantity generated in the shaft 1 is transmitted to the ribbon 2 through the adhesive layer, the adhesive acts as a cushioning material, and the mechanical quantity generated in the shaft 1 is not accurately transmitted. .. Further, there is a problem that the measurement result may vary due to the non-uniform thickness of the adhesive.

On the other hand, in terms of manufacturing, two steps are required, an etching step for forming the slit 5 and an adhering step for integrating the thin strip 2 on which the slit 5 is formed with the shaft 1. Since these two processes are different types of work such as adhesion and etching, separate equipment is required and the process becomes complicated.

The object of the present invention is to solve the above-mentioned problems,
An object of the present invention is to provide a mechanical quantity detection device that can improve measurement accuracy and can simplify the manufacturing process of the device.

[0008]

In order to solve the above-mentioned problems, according to the present invention, a ribbon-shaped mechanical quantity detecting element made of a soft magnetic material is fixed to a member to be measured of mechanical quantity by welding. , And that a low magnetic permeability pattern is formed on the mechanical quantity detection element by welding with the member to be measured.

[0009]

According to the present invention having the above-mentioned characteristics, the fixing of the ribbon-shaped mechanical quantity detecting element, that is, the ribbon, to the member to be measured, and the processing of the slit row, that is, the low magnetic permeability pattern, which has been conventionally performed by etching, are the same. Can be carried out by welding as a processing method.

That is, since the magnetic permeability of the soft magnetic material is greatly reduced by heating by welding, the heated portion is
It performs the same function as a slit formed by conventional etching.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the drawings. FIG. 1 is a view showing an embodiment of the present invention and is a front view of a member to be measured around which a thin strip is wound. Also, FIG.
FIG. 3 is a developed view of the thin strip 2.

In the figure, the shaft 1 is high manganese non-magnetic steel, and the ribbon 2 is an amorphous alloy (for example, Metg mentioned above).
las 2605sc). The ribbon 2 is fixed to the shaft 1 by welding. The portion heated to a high temperature by the welding is shown by a dotted line in the figure. Of these heating parts 6 and 7,
The ribbon 2 is mainly fixed to the shaft 1 by the heating portion 6. In addition, the heating portion 7 forms a low magnetic permeability pattern which is symmetrical with respect to the ribbon 2. When the heating temperature by welding reaches the crystallization temperature of the amorphous material forming the ribbon 2, the magnetic permeability thereof rapidly decreases. For example, the magnetic permeability is 10
Those of about 00μ are reduced to 10μ or less.

The symmetrical low magnetic permeability pattern, that is, the heating portion 7 is formed by expanding the ribbon 2 and, as shown in FIG. 2, the angle θ of 45 ° in different directions with respect to the center line 8 of the shaft 1. When the torque is generated in the shaft 1, the tensile / compressive stress is concentrated in the region between the low magnetic permeability patterns.

Next, a method for welding the ribbon 2 to the shaft 1 will be described with reference to FIG. In FIG. 3, the torch 9 of the electron beam welding machine is reciprocally arranged in the thrust direction 10 of the shaft 1. Further, the shaft 1 is fixed to a jig such as a turntable and rotated in the direction of arrow 11. With such an arrangement, the shaft 1 is first fixed while the torch 10 is fixed.
Is rotated to weld the heated portions 6 at both ends of the ribbon 2. Subsequently, while the torch 9 is reciprocatingly moved, the shaft 1 is rotated and welded while maintaining a predetermined relationship with respect to the stroke and speed of the reciprocating movement to form the heating portion 7.

When the detection device of the present invention is applied to measure the steering force for electric power steering control in a vehicle, for example, the ribbon 2 is welded to a steering shaft or a shaft connected to the steering shaft to form a detection portion. can do.

In this embodiment, the shaft to which the member to be measured receives the torque has been described above. However, the target is not limited to such shaft, and even if the plate causes bending strain due to pressure, this embodiment is also applicable. The pressure can be measured in the same manner as.
In the present embodiment, the ribbon 2 is made of an amorphous alloy,
The shaft 1 was made of high manganese magnetic steel, but in addition to this, a good effect was obtained when a ribbon of an amorphous alloy was welded to a shaft made of a titanium alloy. The ribbon is not limited to these combinations, and the ribbon may be made of a soft magnetic material as long as it has a significantly reduced magnetic permeability when heated to the crystallization temperature. On the other hand, it is desirable that the shaft 1 has a coefficient of thermal expansion substantially similar to that of the ribbon. In the present embodiment, although the illustration of the thin band 2, that is, the coil arranged corresponding to the mechanical quantity detection element and the details of the detection method are omitted, the principle of measurement for detecting the inductance change of the coil as an output is conventional. Technology can be used without any change.

[0017]

As is apparent from the above description, according to the present invention, the following effects can be obtained. (1) Since the ribbon and the shaft are fixed by welding, there is no risk of peeling during repeated use, and reliability is improved. (2) Since the mechanical quantity applied to the shaft is directly transmitted to the detecting element, that is, the ribbon through the welded portion, the accuracy is improved. (3) The manufacturing process is unified with the welding process and simplified.

[Brief description of drawings]

FIG. 1 is a front view of a main part of a detection device according to an embodiment of the present invention.

FIG. 2 is a development view of a physical quantity detection element.

FIG. 3 is a diagram showing a manufacturing process of the detection device of the present invention.

FIG. 4 is a cross-sectional perspective view showing a conventional detection device.

[Explanation of symbols]

1 ... Shaft, 2 ... Thin band, 3, 4 ... Detection coil, 5 ... Slit, 6, 7 ... Heating part, 9 ... Welding torch

Claims (1)

Claim: What is claimed is: 1. A change in permeability due to a strain generated in a ribbon-shaped mechanical quantity detection element made of a soft magnetic material fixed to a member to be measured is arranged corresponding to the mechanical quantity detection element. In a mechanical quantity measuring device that detects a change in the inductance of a coil and measures the mechanical quantity that causes the distortion based on the detected value, the mechanical quantity detecting element is fixed to the measured member by welding. And a low-permeability pattern formed on the mechanical-quantity detecting element by welding with the member to be measured.