KR20140016738A - Linear displacement sensor and linear displacement detecting system using electromagnetic induction - Google Patents

Abstract

Provided in the present invention are a linear displacement sensor using an electromagnetic induction method and a linear displacement measuring system for a movable object using the same, which can effectively detect the linear position of a movable object by adopting a simple mechanical composition and can be manufactured on a mass production basis at a low cost. The linear displacement sensor comprises: a core; an input coil which is wound at one side of the core, and forms a time-varying magnetic field by being supplied with a time-varying current; an output coil which is placed in parallel with the input coil at a fixed interval, and induces voltage by being influenced by the time-varying current; and a translator including an electric conductor which performs a relative straight-line motion along with the input and output coils inside the time-varying magnetic field formed around the input coil. The translator is a trapezoidal plate shaped structure where the straight-ling motion direction is a long side direction, and the vertical direction to the straight-ling motion direction is a short side direction. In the translator, two facing sides in the short side direction are in parallel to each other; one side between facing two sides in the long side direction is vertical to the two sides in the short side direction; the other side between facing two sides in the long side direction has a shape where a gradient thereof changes in a linear or a constant function form as going from one end to the other end. Therefore, the linear displacement sensor can measure the displacement of a straight-line movement of the movable object by measuring changes in the voltage in the output coil depending on the changes in the area of the translator inside the time-varying magnetic field during the relative straight-line motion of the translator and the input and output coils.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a linear displacement sensor using an electromagnetic induction method,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a linear displacement sensor for measuring a linear displacement of a movable object and a linear displacement measurement system for the movable object using the linear displacement sensor. More particularly, The present invention relates to a linear displacement sensor having an electromagnetic induction measurement method capable of mass production at low cost and a linear displacement measurement system for a movable object using the linear displacement sensor.

In general, a displacement sensor (or a position sensor) is used for measuring the rotational angle and the displacement of various mechanisms. The displacement sensor is classified into a contact type and a non-contact type according to the shape of a mechanical structure. A non-contact type, a hall element type, an inductive sensing type or a coded disk shaft type encoder.

A contact type displacement sensor typified by an electric resistance type displacement sensor is a resistance plate processed on a PCB substrate or a ceramic substrate and has many problems in terms of durability degradation due to brush wear or resistance failure, There is a problem.

On the other hand, the non-contact type displacement sensor may have a cost increase depending on the structural type, but it has superior characteristics in terms of durability and accuracy as compared with the contact type displacement sensor. Such a displacement sensor includes a linear displacement sensor for detecting a change in position on the same straight line and a rotational displacement sensor for detecting a change in the rotation angle.

An example of a linear displacement sensor for detecting a position on the same straight line is disclosed in U.S. Patent No. 7,088,095. The linear displacement sensor disclosed in this publication has a Hall sensor having two permanent magnets for generating a magnetic field and disposed in a magnetic field region forming a linear measurement section. The hall sensor and the magnetic field generating device are installed so as to be linearly movable with respect to each other along the longitudinal direction, so that the position of the hall sensor can be determined within the measurement section. In addition, the permanent magnets are polarized so as to have a polarity in the transverse direction perpendicular to the longitudinal direction. Therefore, the N pole and the S pole of each permanent magnet are arranged so as to be located at the end portion opposite to the transverse direction. The two permanent magnets provided in the displacement sensor for generating a linear magnetic field in the measurement section are adapted to extend along the entire measurement section and longitudinally at the sides beyond both ends of the measurement section. In addition, the permanent magnets are arranged so as to have opposite polarities, for example, two S poles facing each other. In addition, the two permanent magnets are kept convexly bent on the inner surface facing each other toward the measurement section, so that a desired linear magnetic field can be obtained in the measurement section by the curved curvature.

However, the conventional linear displacement sensor having the above-described structure has a problem that the manufacturing cost is increased because the sensor has a relatively large number of internal components and a complicated structure. In addition, there is a risk that the linearity of the desired magnetic field may be largely erroneous due to the tolerance generated when the curved inner surface is formed. In order to keep the Hall sensor in the linear region of the magnetic field, And there was a lot of structural problems such as the need to adjust the position.

SUMMARY OF THE INVENTION Accordingly, the present invention has been made keeping in mind the above problems occurring in the prior art, and it is an object of the present invention to provide a translator in a time-varying magnetic field region in a relative linear motion of an input / output coil and a conductor, It is possible to manufacture a linear displacement sensor having excellent performance at a low cost by applying a simple mechanical configuration by measuring a linear movement displacement of a movable object by detecting a change in voltage induced in an output coil according to an area change, And a linear displacement measurement system for a movable object using the linear displacement sensor.

According to an aspect of the present invention, there is provided a linear displacement sensor using an electromagnetic induction method, the linear displacement sensor including: a core; An input coil wound on one side of the core and applying a time-varying current to form a time-varying magnetic field; An output coil disposed parallel to the input coil at a predetermined interval, the voltage being induced by the time-varying magnetic field generated by the input coil; And a translator composed of conductors that perform relative linear motion with respect to the input and output coils within a time-varying magnetic field region formed around the input coil, wherein the translator has a rectilinear motion And a direction orthogonal to the linear motion direction forms a short side direction, wherein two opposing sides in a short side direction of the structure are parallel to each other, and two mutually opposing sides in the long side direction Is formed so as to have a shape in which the inclination is changed (increased or decreased) in a linear or constant function form from one end to the other end, while the other side is perpendicular to the two sides in the short side direction , The change in the area of the translator within the time-varying magnetic field region during the relative linear movement of the input / output coils and the translator It is characterized in that it is formed to measure the linear displacement of the animal body by measuring the change in voltage in the output coil according to.

Here, the input / output coil and the translator may be configured to be held in a fixed state while the other may perform linear motion, and the moving object may be coupled to one side of the linear motion .

The translator may be configured to perform relative linear motion with the input and output coils while being disposed in a non-contact state in a space between the input coil and the output coil.

Alternatively, the translator may be configured to perform a relative linear motion with the input / output coil in a state in which the translator is disposed in a non-contact state with an outer portion spaced from the input / output coil by a predetermined distance.

According to another aspect of the present invention, there is provided a linear displacement measurement system using electromagnetic induction, comprising: a time-varying current supply device for supplying a time-varying current; An input coil having a core, an input coil wound on one side of the core and applied with a time-varying current to form a time-varying magnetic field, and an output coil disposed parallel to the input coil at a predetermined interval, A linear displacement sensor including an output coil from which a received voltage is induced and a translator composed of conductors that perform relative linear motion with the input and output coils in a time-varying magnetic field region formed around the input coil; A detecting device for detecting a voltage or a current induced in an output coil of the linear displacement sensor during linear motion of the movable object; And an arithmetic unit for calculating a linear displacement of the movable object by comparing the voltage or current detected by the detection unit with a reference value, wherein the translator is configured such that the rectilinear motion direction is a long side direction, Wherein two opposite sides of the short side are parallel to each other and one side of the two sides facing each other in the side direction of the long side is a short side of the short side And the other side is formed so as to have a shape that the slope changes (increases or decreases) linearly or constantly in a function form from one end to the other end, and the input / output coil Variation of the voltage in the output coil with the area change of the translator in the time-varying magnetic field area during the relative linear motion of the translator And that a form to measure a linear displacement of a movable object by measuring the features.

Here, the present invention may further include an amplifier for amplifying the voltage or current detected by the detection device.

Also, an A / D converter (Analog to Digital Converter) for converting an analog signal amplified through the amplifier to a digital signal may be additionally provided.

In addition, a display device for displaying the linear displacement of the movable object may be further provided according to the result calculated by the calculation device.

According to the present invention having the above-described configuration, the shapes of the input and output coils wound around the core and the translator moving relative to each other linearly increase (or decrease) in a linear or constant function And a linear movement displacement of the movable object is measured by detecting a change in the voltage induced in the output coil in accordance with the area change of the translator in the time-varying magnetic field area during relative movement between the input and output coils and the translator, It is advantageous to realize a linear displacement sensor having excellent performance at a low cost by applying a simple mechanical structure using an electromagnetic induction method. The manufactured linear displacement sensor can be used as a displacement sensor of a linear actuator.

1 is a perspective view illustrating a linear displacement sensor using an electromagnetic induction method according to a first embodiment of the present invention;
Fig. 2 is a side view of the linear displacement sensor shown in Fig. 1; Fig.
3 is a perspective view illustrating a linear displacement sensor using an electromagnetic induction method according to a second embodiment of the present invention.
Fig. 4 is a side view of the linear displacement sensor shown in Fig. 3; Fig.
5 is a view showing a moving object linear displacement measurement system using an electromagnetic induction method according to an embodiment of the present invention.
6 is a block diagram illustrating a moving object linear displacement measurement system according to another embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a perspective view illustrating a linear displacement sensor using an electromagnetic induction method according to a first embodiment of the present invention, and FIG. 2 is a side view of the linear displacement sensor shown in FIG. 1.

1 and 2, a linear displacement sensor 100 using an electromagnetic induction method according to an embodiment of the present invention includes a core 110, an input coil 120, an output coil 130, and a translator 150.

The input coil 120 is wound on one side of the core 110 and connected to a time-varying current supply device 200 to be described later. The output coil 130 is wound on the core 110 spaced apart from the input coil 120 And is connected in parallel with the input coil 120 and with a detecting device 300 described later.

Therefore, when a time-varying current (a power source whose current changes with time) is supplied to the input coil 120 in the time-varying current supply device 200, a time-varying magnetic field is formed around the input coil 120, The voltage is induced in the output coil 130 located in the time-varying magnetic field formed by the voltage-controlled oscillator.

The translator 150 is a trapezoidal plate-like structure having a certain length made of a conductor and is installed so as to be linearly movable in a state of being placed in parallel between the input coil 120 and the output coil 130 in a noncontact state . A movable object (not shown) is coupled to one side of the translator 150 so that the translator 150 can move linearly when the movable object moves linearly. The translator 150 performs a linear movement in a time-varying magnetic field region formed around the input coil 120 and induces a change in voltage or current to the output coil 130 side.

2, the translator 150 has a non-inverted trapezoidal structure in which the rectilinear motion direction forms the long side direction and the direction perpendicular to the rectilinear motion direction forms the short side direction. That is, the two sides 151 and 152 of the translator 150 facing each other in the direction of the short side of the translator 150 are parallel to each other, and one of the two sides 153 and 154 facing each other Is perpendicular to the two sides 151 and 152 in the short side direction and the other side 154 changes in a linear or constant function form from one end to the other end ).

The translator 150 having such a structure is provided with the input coil 120 and the input coil 120 in a state in which the one side 153 of the longer side in the lateral direction perpendicular to the two sides 151, And is disposed in a space between the output coils 130 in a non-contact manner to perform a linear motion.

At this time, the translator 150 has a shape in which one side 154 of the long side of the translator 150 is increased (or decreased) in a linear or constant function form along the linear motion direction. For example, when the height of one end of the translator 150 is h, the height of the other end of the translator 150 is linearly increased by? H, H < / RTI > Thus, when the translator 150 linearly moves within the time-varying magnetic field forming region formed around the input coil 120, the output signal from the output coil 130 Which affects the time-varying magnetic field, causing a change in voltage or current in the output coil 130. [

Using this principle, after measuring the voltage or current in the output coil 130 in the state where the translator 150 is stopped, the translator 150 is guided to the output coil 130 in a linearly shifted state The displacement or displacement of the translator 150 can be known by comparing the measured voltage and current.

Therefore, when the moving object to be measured is moved to the translator 150, the translator 150 interlocks with the input coil 120 and the output coil 130 So that it is possible to measure the displacement of the movable object by measuring the voltage induced in the output coil 130.

In this case, in the above-described embodiment, the structure including the core 110 and the input and output coils 120 and 130 is fixed, and the translator 150 moves linearly between the input and output coils 120 and 130. However, on the contrary, the translator 150 may be fixed and the input and output coils 120 and 130 may be configured to linearly move. In this configuration, a moving object (not shown) can engage with the linear motion input / output coil 120 (130) structure.

FIG. 3 is a perspective view illustrating a linear displacement sensor using an electromagnetic induction method according to a second embodiment of the present invention, and FIG. 4 is a side view of the linear displacement sensor shown in FIG. 3.

The linear displacement sensor 100 of the present invention shown in Figs. 3 and 4 has the same basic configuration and operation principle as the linear displacement sensor 100 shown in the first embodiment described above, (120) 130 and the translator (150).

That is, the input coil 120 and the output coil 130 are wound on the lower side of both ends of the core 110 and have a trapezoidal shape on the lower side spaced apart from the input / output coils 120 The translator 150 is disposed in a non-contact state to perform relative linear motion with the input / output coils 120 and 130. [

Therefore, when the translator 150 is linearly moved in the time-varying magnetic field forming region formed on the lower side of the input coil 120, the translator 150 is guided to the output coil 130 in accordance with the lateral width W of the translator 150 It is possible to measure the linear movement displacement of the movable object by detecting a change in voltage or current.

FIG. 5 is a block diagram showing a movable body rotation angle measuring system including the above-described electromagnetic induction type angle sensor of the present invention.

5, the moving object linear displacement measuring system using the electromagnetic induction method according to an embodiment of the present invention includes a time-varying current supplying device 200, a linear displacement sensor 100, a detecting device 300, (400) and a display device (700).

The time-varying current supply device 200 is a device for supplying a time-varying current to the input coil 120 of the shock type displacement sensor 100. The time-varying current is supplied to the input coil 120 through the time- A time-varying magnetic field is formed around the input coil 120.

The linear displacement sensor 100 includes a non-inverted trapezoidal type translator 150 that linearly moves between an input coil 120 and an output coil 130 and between the input coil 120 and the output coil 130 The configuration and operation principle of the linear displacement sensor are as described above.

The detection device 300 is a device for detecting a current and a voltage induced in the output coil 130 when the movable object linearly moves. As the detection device 300, an ammeter or a voltmeter may be used, and the voltage or current in a stationary state in which the translator 150 is not moved, and the voltage or current value according to the linear movement of the translator 150 in advance After securing, the linear movement displacement of the animal body can be known by comparing the current or voltage values detected by the detection device 300 while the animal body is linearly moved.

The comparison of the current or voltage value detected by the detecting apparatus 300 with the voltage or current in the state in which the translator 150 does not move linearly and the voltage or current in accordance with the linear movement of the translator 150, And the operation result of the calculation device 400 is displayed on the screen through the display device 700 so that the user can easily recognize the movement displacement of the moving object.

FIG. 6 illustrates another embodiment of the present invention, in which a filter, an amplifier, and an A / D converter are additionally included in the moving object linear displacement measurement system shown in FIG.

6, the movable object linear displacement measurement system according to another embodiment of the present invention includes a filter 500, an amplifier 600, an A / D converter (not shown) An analog to digital converter 800 is further included.

That is, when the voltage or the current value measured by the detecting device 300 of the moving object linear displacement measuring system is low, it may be difficult to confirm an accurate value. To solve this problem, in the detecting device 300, And the amplified analog signal is converted into a digital signal through the A / D converter 800 and outputted to the detection device 300, The correct voltage or current value can be detected.

As described above, the present invention is characterized in that the shapes of the input and output coils 120 (130) wound on the core 110 and the translator 150 performing the relative linear motion are gradually shifted in the linear motion direction from linear (Or reduced) in response to change in the area of the translator 150 in the time-varying magnetic field area when the input / output coils 120, 130 and the translator 150 are relatively moved, By detecting a change in the voltage induced in the coil 130 and measuring a linear movement displacement of the movable object, it is possible to realize a linear displacement sensor having a superior performance at a low cost by applying a simple mechanical configuration using an electromagnetic induction system There are advantages. The manufactured linear displacement sensor can be used as a displacement sensor of a linear actuator.

While the present invention has been described in detail with reference to the specific embodiments thereof, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims. It should be understood that the above-described embodiments are illustrative in all aspects and that the present invention is not limited to what is described in the present specification. It is to be understood that the scope of the present invention is defined by the appended claims rather than the foregoing description and all changes or modifications derived from the meaning and scope of the claims and their equivalents are included in the scope of the present invention Should be interpreted.

100: linear displacement sensor 110: core
120: input coil 130: output coil
150: Translators 200: Time-varying current supply
300: detecting device 400: calculating device
500: filter 600: amplifier
700: Display device 800: A / D converter

Claims (8)

A core;
An input coil wound on one side of the core and applying a time-varying current to form a time-varying magnetic field;
An output coil disposed parallel to the input coil at a predetermined interval, the voltage being induced by the time-varying magnetic field generated by the input coil; And
And a translator composed of conductors that perform relative linear motion with respect to the input and output coils within a time-varying magnetic field region formed around the input coil,
Wherein the translator is a trapezoidal plate-like structure in which a rectilinear motion direction is a long side direction and a direction perpendicular to the rectilinear motion direction forms a short side direction, wherein two opposing sides in the short side direction are parallel to each other, One side of the two sides facing each other in the direction of the long side is perpendicular to the two sides in the direction of the short side, and the slope changes linearly or constantly in the form of a function from the other side to the other side Increasing or decreasing)
It is formed to measure the linear displacement of the animal body by measuring the change of the voltage in the output coil according to the change of the translator area in the time-varying magnetic field area during the relative linear movement of the input, output coil and the translator Linear displacement sensor using electromagnetic induction
2. The apparatus according to claim 1, characterized in that either one of the input / output coil and the translator is held in a fixed state, the other performs linear motion, and the movable object is coupled to one side performing the linear motion A linear displacement sensor using an electromagnetic induction method
The linear displacement sensor according to claim 1, wherein the translator performs relative linear motion with the input and output coils in a state in which the translator is disposed in a non-contact state between the input coil and the output coil.
The electromagnetic induction method of claim 1, wherein the translator performs a relative linear motion with the input and output coils in a state in which the translator is disposed in a non-contact state at a predetermined distance from the input and output coils. Linear displacement sensor
A time-varying current supply device for supplying a time-varying current;
An input coil having a core, an input coil wound on one side of the core and applied with a time-varying current to form a time-varying magnetic field, and an output coil disposed parallel to the input coil at a predetermined interval, A linear displacement sensor including an output coil from which a received voltage is induced and a translator composed of conductors that perform relative linear motion with the input and output coils in a time-varying magnetic field region formed around the input coil;
A detection device for detecting a voltage or current induced in an output coil of the linear displacement sensor during linear movement of the animal body; And
And a computing device for calculating a linear displacement of the movable object by comparing a voltage or current detected by the detection device with a reference value,
Wherein the translator is a trapezoidal plate-like structure in which a rectilinear motion direction is a long side direction and a direction perpendicular to the rectilinear motion direction forms a short side direction, wherein two opposing sides in the short side direction are parallel to each other, One side of the two sides facing each other in the direction of the long side is perpendicular to the two sides in the direction of the short side, and the slope changes linearly or constantly in the form of a function from the other side to the other side Increasing or decreasing)
The linear movement of the animal body is measured by measuring the change in voltage at the output coil according to the change of the translator area in the time-varying magnetic field during the relative linear motion of the input and output coils. Linear displacement measurement system of animal body using electromagnetic induction method.
The linear displacement measurement system according to claim 5, further comprising an amplifier for amplifying the voltage or current detected by the detection device.
The system of claim 5, further comprising an analog-to-digital converter for converting the analog signal amplified by the amplifier into a digital signal. .
The system of claim 5, further comprising a display device for displaying the linear displacement of the animal according to the result calculated by the computing device.

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