JPS5957103A - Strain gauge - Google Patents

Abstract

PURPOSE:To enable high preciseness measurement, by a method wherein a plurality of magnetic heads are provided to a position capable of reading a magnetic scale to read the graduations of the magnetic scale and the output thereof is operated to be analyzed. CONSTITUTION:An object 1 to be measured, a wire or strip like magnetic scale 2, a scale attaching part 3 for attaching one end of the magnetic scale 2, a scale attaching part 4 for attaching the other end of the magnetic scale 2, a spring 5, scale guides 6, magnetic heads 7 and an operation apparatus 8 are provided. When the object 1 to be measured is deformed by external force and generates strain, the scale guides 6 and the magnetic heads 7 attached to the strain generated part of the object 1 to be measured are moved relative to the magnetic scale 2. The moved graduations of the magnetic scale 2 are read by the magnetic heads 7 and the outputs of these magnetic heads 7 are analyzed by the operation apparatus 8 to calculate the strain of the object 1 to be measured.

Description

[Detailed description of the invention] The present invention relates to a strain meter.

Conventionally known strain meters include resistance wire strain meters, but these strain meters have a narrow measurement range and can only measure a portion of the object to be measured.Moreover, since they use impedance conversion, they are not suitable for measuring the resistance of resistance wires. The equipment becomes complicated because it requires a measurement circuit such as a bridge circuit, and since the change in resistance is small, the amplification factor of the measurement circuit must be increased, which reduces the S/N ratio, and furthermore, the temperature rises due to heat generation in the resistance wire. There was a problem in that temperature compensation had to be made because of the influence of temperature.

The present invention has been made based on the above-mentioned viewpoints, and its purpose is to be able to measure strain over the entire object, regardless of its shape, and to use a digital method. An object of the present invention is to provide a strain meter which has a large /N ratio, can be easily constructed, can perform measurements with extremely high accuracy, and is not affected by temperature rise due to heat generation since no resistance wire is used.

The gist of the present invention is to provide a pair of scale mounting sections and a plurality of scale guides on an object to be measured, and to insert an appropriate magnetic scale from one of the scale/mounting sections in a predetermined order. The other scale mounting is arranged along a path that passes through the scale guide and reaches the part, one end of which is directly connected to the part, and the other end is elastically connected via a spring. The other one of the above is attached to each section, and furthermore, a plurality of magnetic heads are arranged at positions where the above magnetic scale can be read, the scale of the magnetic scale is read by these magnetic heads, and the output is calculated. The purpose is to calculate the strain of the member to be measured by analyzing it with the device.

The details of the configuration of the present invention will be explained below with reference to the drawings.

In each figure, the same reference numerals indicate components having the same function.

FIG. 1 is an explanatory diagram showing an embodiment of the strain meter according to the present invention,
Fig. 2 is an explanatory diagram showing another embodiment of the present invention, Fig. 3 is an explanatory diagram showing yet another embodiment, and Fig. 4 is an embodiment of the present invention in which the object to be measured is a machine tool. FIG.

In the NS1 diagram, 1 is the object to be measured, 2 is a wire or strip-shaped magnetic scale, 3 is the scale attachment part for attaching one end of the magnetic scale, and 4 is the scale attachment part for attaching the other end of the magnetic scale (=
J number) scale removal ("J part, 5 is spring, 6
1 is a scale guide, 7 is a magnetic head, and 8 is an arithmetic unit.

The magnetic scale is placed at key points on the wire or strip-shaped magnetic material.
It has a magnetic grating (magnetic scale) with magnetic poles vertically or in some cases horizontally magnetized at intervals of pm -10 prns or about 1100 tr, and the scale is guided from the scale mounting part 3 in the order shown in the figure. Wt 6
V: Reaches the other scale 00 part 4 via V:
Its one end is attached to and in contact with part 3, and the other end is elastically attached to part 4 via a spring 5, and a certain tension is applied by the spring 5. There is.

The magnetic head 7 is provided at a key point in the part where the strain is to be measured, and is configured so as to lightly touch the magnetic scale 2 or to approach it at a predetermined minute interval so as to detect the scale of the magnetic scale 2.

When the measured object 1 is deformed by an external force and causes distortion, the measured object 1
Since the scale guide 6 and magnetic head 7 attached to the distorted part move relative to the magnetic scale 2, the scale guide 6 and the magnetic head 7 that are attached to the part where the distortion has occurred move with respect to the magnetic scale 2. is analyzed by a calculation device to calculate the strain of the object to be measured 1.

In the above case, it is recommended that the magnetic head 7 and the magnetic scale 2 be engaged by appropriate means so that they do not separate from each other due to deformation and distortion of the object to be measured l. Conversely, a separation greater than the above-mentioned predetermined value can also be used for measurement.

FIG. 2 is an explanatory diagram showing an embodiment of a strain meter in which a plurality of magnetic scales are attached to a member to be measured.

The magnetic scales 2 and 2' are attached to one scale mounting part 3.3.
', the scale guide 6.6' is successively passed through the scale guide 6.6' in the illustrated order to reach the other scale mounting part 4.4', one end of which is directly connected to the mounting part 3.31 and the other scale mounting part 4.4'. One end is elastically attached to each of the mounting sections 4.4' via a spring 5.51, which provides a constant tension.

When the object to be measured 1' is deformed and distorted by an external force, the magnetic head 7.71 attached to the distorted part of the object to be measured 1 moves relative to the magnetic scale 2.2'. 7' reads the moved graduations of the magnetic scale 2.2', and furthermore, the outputs of these magnetic heads are analyzed by an arithmetic unit to calculate the strain of the object to be measured 1.

According to the embodiment in which a plurality of magnetic scales are provided as described above, strain can be measured over a wider range than measurement using a single magnetic scale, and the length of one magnetic scale can be shortened, thereby reducing measurement errors. can do.

There are two types of strain: one caused by external force and the other caused by uneven temperature distribution. Judgment can be made by using them together.

Figure 3 shows the strain δ1 used in combination with magnetic scales whose expansion coefficients are the same as and different from the expansion coefficient of the measured object.
It is an explanatory diagram without showing the implementation.

In FIG. 3, the magnetic scale 2 is the same as the measurement target 1. A wire having a low coefficient of thermal expansion, such as a magnetic scale of 21 scales, is used, and platinum-cobalt pieces with magnetic scales are attached to important points of the wire.

When the measured object 1 is deformed and distorted by heat and external force, a scale guide is attached to the distorted part of the measured object 6.
6' and magnetic/magnetic head 7.7' are magnetic scales 2.2'
move against. At this time, the magnetic scale 2 undergoes thermal expansion in the same way as the object to be measured 1, and since the magnetic scale 2' is made of a magnetic material with a low coefficient of thermal expansion, almost no deformation occurs. Magnetic scale 2.2' by magnetic head 6.6'
The scales that have been moved are continued, and the outputs of these magnetic heads are further analyzed by an arithmetic device to calculate the strain of the object to be measured 1.

In this case, thermal strain is generally detected by the difference in the amount of movement between magnetic scales 2 and 21, and the strain caused by external force is considered to be common to both scales, so if the amount of movement of both magnetic scales 2 and 2' is analyzed, thermal strain Distortion and external force distortion can be known separately.

FIG. 4 is an explanatory diagram showing an embodiment of the present invention in which the member to be measured is a machine tool.

The magnetic scale 2 is installed on one side of the machine tool, but it is recommended that it be installed not only on the side but in areas where distortion is likely to occur, and use one with a low coefficient of expansion, such as Imphal.

When the object to be measured 1 is deformed and distorted by heat, the magnetic head 7 attached to the distorted part of the object to be measured 1 moves, but since the magnetic scale 2 is made of a magnetic material with a low coefficient of thermal expansion, Almost no deformation occurs, and the movement of the magnetic head 7 can be detected as a movement of the scale of the magnetic scale 2. Therefore, the moved scale of the magnetic scale 2 is read by the magnetic head 7, and the outputs of these magnetic heads are then read by a computing device. Analyze and calculate the distortion of measured holiday 1.

In addition, as in the embodiment shown in FIG. 3, if a magnetic scale having the same expansion coefficient as the object to be measured and a magnetic scale having a different expansion coefficient are used together, thermal strain and external force strain can be determined separately. Can be done.

Since the present invention is structured like a ridge, it is possible to measure strain over the entire object regardless of its shape, and since it is a digital method, S
/N ratio is large, equipment can be easily constructed, and extremely 7tr
It is possible to provide a strain meter that can perform measurements with J accuracy and is not affected by temperature rise due to heat generation since no resistance wire is used.

Note that the configuration of the present invention is not limited to the embodiment on the ridge. The shape of the object to be measured can be arbitrary, and the shape of the magnetic scale can be linear, rod-shaped, strip-shaped, etc., and the set positions of the scale guide, magnetic scale, and magnetic head are within the scope of the purpose of the present invention. The design can be changed freely, and the present invention encompasses all of them.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing an embodiment of the strain meter according to the present invention,
FIG. 2 is an explanatory diagram showing another embodiment of the present invention, FIG. 3 is an explanatory diagram showing yet another embodiment, and FIG. 4 is an embodiment of the present invention in which the member to be measured is a machine tool. FIG. ■−・・〜−−−−−−−−−−−Object to be measured 2−−−−
-------・-1---Magnetic scale 3.4------
−Scale removal part 5−・−−−−−−−−−−
−・〜−−−−Spring 6−−−−−−−−−−−
1------------Scale guide 7------・--
---1--------Magnetic head 8----
--------～--1--Arithmetic device patent applicant Wat Inoue Japax Research Institute Agent (7524) Shota Mogami Figure 1 Figure 2: Figure 3 Figure 4

Claims (3)

[Claims] (1) A pair of scale mounting sections and a plurality of scale guides are provided on the object to be measured, and an appropriate magnetic scale is sequentially passed from one of the scale mounting sections to the other through the scale guides in a predetermined order. The scale attachment is arranged along the path leading to the part, one end of which is directly attached to the part, and the other end is elastically connected to the other part through a spring. A plurality of magnetic heads are installed at positions where the magnetic scale can be read, and an arithmetic unit is connected to analyze the output of these magnetic heads to calculate the strain of the member to be measured. Strain meter. (2) The strain meter according to claim 1, wherein a plurality of uI magnetic scales are attached. (3) The strain meter according to claim 1 or 2, wherein a magnetic scale whose expansion coefficient is the same as that of the object to be measured and a magnetic scale whose expansion coefficient is different from that of the object to be measured are used together.