JPH0196511A - Displacement detecting element and displacement arithmetic element - Google Patents

Abstract

PURPOSE:To raise the reliability of a detection and an arithmetic operation of a displacement by a simple and inexpensive constitution by providing a means by which a detection output is proportional to the displacement quantity as it is. CONSTITUTION:An exciting coil 2 and a detecting coil 3 as a first and second conductor coils are provided so as to be separated from each other on both end parts of a soft magnetic material pattern 1, and to the coil 2, an alternating current source 20 is connected, and also, on the periphery of the coil 3, a conductor shield 4 is provided in a non-contact state to the pattern 1, and also, so as to be movable. When coil length of the coil 3 and an overlap of the shield 4 and the coil 3 are denoted as Lc and (x), respectively, a magnetic field is generated from the end part of the excited shield 4, its magnetic field induces an eddy current 40 in the shield 4, a reverse magnetic field is applied to the overlap (x) of the coil 1 and the shield 4 and the magnetic flux density of its part becomes zero. As a result, an induction voltage of the coil 3 becomes only an induction voltage generated in the coil of length of Lc-(x). Also, when the shield is provided on both end parts of the pattern 1, two displacement quantities can be operated.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a displacement detection element and a displacement calculation element, and particularly to a displacement detection element and a displacement calculation element, which detect displacement without contact and calculate the sum, difference, product, etc. of the magnitude of two displacements. The present invention relates to a displacement detection element and a displacement calculation element as an element for calculating.

[Conventional technology]

In numerically controlled machine tools, etc., it is an extremely important technology to accurately detect the displacement of an object. Conventionally, the following techniques are widely known as techniques for detecting the displacement of an object.

That is, a method that converts the amount of displacement into an electrical resistance value via a potentiometer, a method that uses a strain gauge, a method that uses a magnet scale that uses the Hall effect or magnetoresistive effect, a method that uses an optical encoder, and a method that uses laser light reflection and its effects. These include optical interferometry that uses a phase shift, and ultrasonic interferometry that uses ultrasound reflection and its phase shift.

In order to detect displacement with a potentiometer, it is necessary to bring the electric resistor and the position detection electrode into contact with each other and to cause them to slide against each other. In this method, contact sliding of the electrodes is essential.

A strain gauge detects the amount of strain based on a change in electrical resistance value when the length of an electrical resistance wire changes. Therefore, in order to detect the displacement of an object, it is necessary to connect the object and the reference position using this strain gauge.

Magnescale is a linear high-coercivity magnetic material that is regularly magnetized in the normal and reverse directions along its length. A magnetic field sensor using the Hall effect or magnetoresistive effect is provided near this magnetescale. The magnetic field sensor is moved along the entire magnet scale, and the amount of movement, that is, the displacement of the magnetic field sensor is calculated using the number of changes in the magnetic field detected by the magnetic field sensor.

Displacement detection using an optical encoder also calculates displacement from a scale with a complex optical pattern and changes in light intensity, similar to the Magnescale.

Displacement measurement using optical interferometry or ultrasonic interferometry involves irradiating an object with light or ultrasonic waves emitted from a light source or sound wave source, detecting the phase of the light or ultrasonic waves reflected from the object, and measuring the movement of the object. The displacement is calculated by detecting the change in phase associated with the change in phase.

In addition, when calculating the sum, difference, product, etc. using two displacement amounts, it is necessary to calculate the displacement using these displacement measurement means and then calculate it again using a calculation means or an arithmetic circuit. there were.

[Problem that the invention seeks to solve]

The conventional displacement detection techniques described above each have the following drawbacks.

That is, in the technology of detecting displacement using a potentiometer, since contact and sliding of the phase detection electrode is essential, there are problems with durability and reliability due to wear.

The technique of detecting displacement with a strain gauge has the disadvantage that repeated use causes plastic deformation of the electrical resistance wire, lacks reliability, and furthermore makes it difficult to measure displacement in the compression direction.

The technique of detecting displacement using Magnescale has the disadvantage that it not only requires a complicated configuration but also requires expensive calculation means.

The technique of detecting displacement using an optical encoder has the disadvantage that, like the Magnescale, it requires a scale with a complicated optical pattern and a complicated circuit for calculating displacement from changes in light intensity.

The technology to detect υ displacement using optical interferometry or ultrasonic interferometry is
In addition to requiring an expensive light source and sound source, this method requires a highly accurate phase detector and a high-performance calculation means for calculating displacement from the detected phase change.

Furthermore, when measuring the sum, difference, product, etc. using two displacement amounts, there is a drawback that it is necessary to calculate the displacement again after calculating the displacement with each of the above-mentioned displacement measuring means.

SUMMARY OF THE INVENTION An object of the present invention is to eliminate the above-mentioned drawbacks and to provide a displacement detection element and a displacement calculation element that are easy to measure and capable of highly reliable displacement detection and displacement calculation with a simple and inexpensive configuration.

[Means for solving problems]

In the displacement detection element of the present invention, a first conductor coil and a second conductor coil are respectively provided at two locations apart from each other on a rod-shaped soft magnetic body, and an alternating current is applied to the first conductor coil. A metal conductor shield is disposed around the vicinity of the conductor coil, and the overlapping length of the second conductor coil and the metal conductor shield can be made variable, or a rod-shaped soft magnetic material is placed at three points apart from each other. 1st and 2nd respectively
In addition, a third conductor coil is provided such that the first coil is interposed between the second and third conductor coils, and a full alternating current is applied to the first conductor coil, and the second or third conductor coil is A metal conductor shield is arranged around the vicinity of the coil, and the second or third conductor coil having the metal conductor shield arranged thereon has a structure in which the overlapping length with the metal conductor shield can be made variable. .

In addition, in the displacement calculation element of the present invention, first, second, and third conductor coils are respectively arranged at three locations apart from each other on the rod-shaped soft magnetic body, and the first conductor coil is disposed between the second and third conductor coils.
A conductor coil is provided so that an alternating current is applied to the first conductor coil, and the second conductor coil and the third conductor coil are magnetically in opposite directions and electrically in series. and first and second metal conductor shields are provided around the second and third conductor coils, respectively, so that the overlapping lengths of the conductor coil and the metal conductor shield are independent from each other. The first conductor coil is arranged between the second and third conductor coils, and the first conductor coil is arranged between the second conductor coil and the third conductor coil. An alternating current is applied to the first conductor coil, and the second conductor coil and the third conductor coil are magnetically connected in the same direction and electrically connected in series. Said second
and a structure in which first and second metal conductor shields are respectively provided around the vicinity of the third conductor coil so that the overlapping length of the conductor coil and the metal conductor shield can be varied independently, or a rod-shaped soft magnetic material. First and second conductor coils are provided at two locations separated from each other, and an alternating current is applied to the first conductor coil.
A metal conductor shield is disposed around the vicinity of the second coil, and the length of the overlap between the coil and the conductor shield can be independently varied.

[Effect]

The invention operates on the following principles. That is,
An excitation coil is attached to a part of the rod-shaped soft magnetic material to apply an alternating current. When a magnetic flux detection coil is provided at one end of a rod-shaped soft magnetic material separated from the excitation coil, a voltage proportional to the frequency and amplitude of the excitation current is generated in the detection coil due to electromagnetic induction. A shield made of a material with high electrical conductivity is provided to surround this magnetic flux detection coil. The magnetic field generated from one end of the rod-shaped soft magnetic material generates an eddy current in the conductor shield,
This eddy current generates a reverse magnetic field in the magnetic material. Therefore, substantially no magnetic flux exists in the shielded magnetic material portion.

In other words, there is substantially no magnetic flux in the overlapping region of the shield and the magnetic flux detection coil, and the induced voltage generated in the magnetic flux detection coil decreases in proportion to the magnitude of the overlap. Therefore, the size of this overlap corresponds to the displacement. The conductor shield and the magnetic flux detection coil do not need to be in contact with each other, and by using this principle, a non-contact displacement sensor is realized. Furthermore, by providing shields at both ends of the magnetic body, calculation of two displacement amounts becomes possible.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a configuration diagram showing a first embodiment of a displacement detecting element of the present invention. In this embodiment, an excitation coil 2 serving as a first conductor coil and an excitation coil 2 serving as a first conductor coil are provided at both ends of a bar-shaped soft magnetic material pattern 1.
Detection coils 3 as conductor coils are provided spaced apart from each other, and an alternating current is applied to the excitation coil 2 by an alternating current source 20. Further, a metal conductor shield pattern 4 is provided around the detection coil 3 so as to be movable in a non-contact state with the detection coil 3 and the soft magnetic pattern 1.

FIG. 2(A) is an explanatory diagram of the operation of the embodiment shown in FIG.
B) is an output characteristic diagram of the detection coil of the embodiment of FIG. 1. As shown in FIG. 2(A), the coil length of the detection coil 3 at the end of the soft magnetic material pattern 1 is designated as Lc, and the length of the overlap between the conductive shield pattern 4 and the detection coil 30 is designated as X.

A negative magnetic field is generated from the end of the excited soft magnetic material button 4, and the magnetic field induces an eddy current 4o in the conductive shield pattern 4. A reverse magnetic field based on this eddy current 40 is applied to the overlapping portion (length X) of the detection coil 3 and conductive shield pattern 4 of the soft magnetic material pattern 1, and the total magnetic flux density in that portion is made substantially zero. As a result, the induced voltage in the detection coil (3f) is only the induced voltage that occurs in the coil having a length of Lc-x. The dependence of this induced voltage, that is, the detection coil output (2) on the overlap length X becomes a straight line in the range O<x<Lc, as shown in FIG. 2(H)K.

The soft magnetic material button l has a rectangular cross section of 11 m and a length of 30 mm.
Using high-quality NiFe alloy, a 20-turn coil was wound at both ends with a length LC = 1.5 WrIn, and an aluminum conductor shield pattern 4 with an inner diameter of 5 cm and an outer diameter of 8 cm was provided.
When an excitation current with a frequency of 100 kHz and an amplitude of 400 In Ap-p was applied, a change in detection voltage of 10 μm was obtained for a change in overlap length of 1 μm.

FIG. 3(A) is a block diagram of a second embodiment of the displacement detecting element of the present invention, and FIG. 3(H) is an output characteristic diagram of the detection coil of the embodiment of FIG. 3(A). In this example, FIG. 3(A)
As shown in K, the central part of the soft magnetic material pattern 1 has an excitation coil 2 as a first conductor coil, and the symmetrical magnetic ends on both sides have the same windings as second and third conductor coils. A wire number detection coil of 3°5 is provided. Detection coil 3.5
are electrically connected in series. However, magnetically, the winding directions are opposite to each other. The conductor shield pattern 4 is provided near one of the detection coils 3. When the gravity and length of the conductor shield pattern 4 and the detection coil 3 are x=Q, the detection voltage of only the detection coil 3 and the detection voltage of only the detection coil 5 have the same absolute value and opposite polarities. Therefore, the combined detection output obtained by connecting them in series becomes 0. When the overlap length X increases, the detection coil 3
The detection output of the detection coil 5 decreases, but the detection output of the detection coil 5 remains constant, so the combined output of both is as shown in Figure 3 (B).
As shown by K, in the range 0 < x < L c, it increases in proportion to the overlap length X. That is, the feature of this embodiment is that the detection output (2) is proportional to the displacement (X).

FIG. 4(A) is a configuration diagram of a first embodiment of the displacement calculation element of the present invention, and FIG. 4(B) is an output characteristic diagram of the detection coil of the embodiment of FIG. 4(A). As shown in FIG. 4(A)K, the soft magnetic material button 1. Excitation coil 2° detection coil 3, 5
．． The alternating current source 20 is the same as in the second embodiment of FIG. 3(A). The difference from the second embodiment is that a conductive shield pattern 6 is also provided near the detection coil 5. If the length of the overlap between the conductor shield pattern and the detection coil 3 is Xi, and the length of the overlap between the conductor shield pattern 6 and the detection coil 5 is x2, then the output of the detection coil 3.5 alone is as described above. As mentioned in the second embodiment of FIG. 3(A), they are proportional to Xl and X-, respectively. The combined output of both coils is proportional to (XI X2) as shown in FIG. 4(B). That is, this embodiment provides an arithmetic element that can easily determine the difference between two displacement amounts without using any special arithmetic circuit.

FIG. 5(A) is a configuration diagram of a second embodiment of the displacement calculation element of the present invention. As shown in FIG. 5(A), soft magnetic material pattern 1. Excitation coil 2. The detection coil 3.5, the alternating current source 20 and the conductive shield pattern 4.6 are almost the same as those in FIG. 4(A). The difference is that the detection coils 3 and 5
The winding directions are opposite to each other. Assuming that the overlapping length between the conductor shield pattern 4 and the detection coil 3 is xl, and the overlapping length between the conductor shield pattern 6 and the detection coil 5 is x2, the output of the detection coils 3 and 5 alone is shown in Figure 4 (A).
As can be easily seen from the examples, -x1 and -
It is proportional to x2. Therefore, the combined output of both coils is
As shown in Figure (B), K is proportional to (xl+x*). That is, this embodiment provides an arithmetic element that can easily calculate the sum of two displacement amounts without using any special arithmetic circuit.

FIG. 6 is a configuration diagram of a third embodiment of the displacement calculation element of the present invention. Soft magnetic material pattern 1. Excitation coil 2, detection coil 3. The alternating current source 20 is almost the same as the embodiment shown in FIG. The difference between this embodiment and the embodiment shown in FIG.
In this embodiment, a conductor shield pattern 6 is also provided in the vicinity of the excitation coil 2.If the overlapping length with the conductor shield pattern 6 and the excitation coil 3 is Xl, and the overlapping length Q between the conductor shield pattern 6 and the excitation coil 2 is x2, the excitation The magnetic flux generated from the coil decreases in proportion to x2. The detection coil 3 detects the magnetic flux proportional to this X2, but at this time, the detection output decreases in proportion to x1. That is, this detection output is proportional to xl-x2 as a result. In other words, this embodiment provides all arithmetic elements that can easily calculate the product of two displacement amounts without using any special arithmetic circuit.

〔Effect of the invention〕

As described above, according to the present invention, by providing a means in which the detection output is directly proportional to the amount of displacement, a non-contact displacement detection element with high sensitivity, high reliability, and simple configuration, as well as no special This has the effect that a displacement calculation element for two displacement amounts can be realized without requiring a calculation circuit or calculation means.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram showing a first embodiment of the displacement detecting element of the present invention, FIG. 2(A) is an explanatory diagram of the operation of the embodiment of FIG. 1, and FIG. An output characteristic diagram of the detection coil of the embodiment, FIG. 3(A) is a configuration diagram showing a second embodiment of the displacement detection element of the present invention, and FIG. 3(B) is the embodiment of FIG. 3(A). FIG. 4(A) is a configuration diagram showing the first embodiment of the displacement calculation element of the present invention, and FIG. 4(H) is a detection diagram of the embodiment of FIG. 4(A). Coil output characteristic diagram, 5th
Figure (A) is a configuration diagram of the second embodiment of the displacement calculation element of the present invention, Figure 5 (H) is an output characteristic diagram of the detection coil of Figure 5 (A), and Figure 6 is the displacement calculation element of the present invention. FIG. 7 is a configuration diagram of a third example of an arithmetic element. 1...°...° Soft magnetic material slam, 2.°°.°° Excitation coil, 3°5.°°.°° Magnetic flux detection coil, 4,6°°
°...Conductor shield, 11...Magnetic flux, 20...
..... alternating current source, 40 ..... eddy current, 41
...Magnetic flux. Agent Patent Attorney Uchihara Uchihara 1 circle (β small 1st (I3) stumbling figure G4) (β) Figure 4 (β) Plate 5 figure 6 figure

Claims (6)

[Claims] (1) A first conductor coil and a second conductor coil are provided at two mutually distant locations on a rod-shaped soft magnetic material, and an alternating current is applied to the first conductor coil, and an alternating current is applied to the vicinity of the second conductor coil. A displacement detecting element, characterized in that the element has a structure in which a metal conductor shield is disposed on the second conductor coil and the overlapping length of the second conductor coil and the metal conductor shield can be made variable. (2) First, second, and third conductor coils are provided at three mutually distant locations on the rod-shaped soft magnetic material, respectively, so that the first conductor coil is interposed between the second and third conductor coils. At the same time, an alternating current is applied to the first conductor, a metal conductor shield is arranged around the second or third conductor coil, and the second or third conductor is arranged with the metal conductor shield. A displacement detection element characterized by having a structure in which the overlapping length of a coil and a metal conductor shield can be made variable. (3) The second conductor coil and the third conductor coil are magnetically connected in opposite directions and electrically connected in series. Displacement detection element. (4) First, second, and third conductor coils are placed at three mutually distant locations on the rod-shaped soft magnetic material, such that the first conductor coil is interposed between the second and third conductor coils. In addition, an alternating current is applied to the first conductor coil, and the second conductor coil and the third conductor coil are connected magnetically in opposite directions and electrically in series. and a structure in which first and second metal conductor shields are respectively provided around the vicinity of the third conductor coil, and the overlapping length of the conductor coil and the metal conductor shield can be varied independently. Characteristic displacement calculation element. (5) First, second, and third conductor coils are placed at three mutually distant locations on the rod-shaped soft magnetic material, such that the first conductor coil is interposed between the second and third conductor coils. In addition, an alternating current is applied to the first conductor coil, and the second conductor coil and the third conductor coil are connected magnetically in the same direction and electrically in series, and the second conductor coil is electrically connected in series. and having a structure in which first and second metal conductor shields are respectively provided around the vicinity of the third conductor coil, and the overlapping length of the conductor coil and the metal conductor shield can be independently varied. A displacement calculation element characterized by: (6) First and second conductor coils are provided at two locations separated from each other on the rod-shaped soft magnetic material, and an alternating current is applied to the first conductor coil to provide a conductor coil near the first and second coils. A displacement computing element characterized in that a metal conductor shield is arranged around each of the coils, and the overlapping length of the coil and the conductor shield can be independently varied.