JP3846794B2 - Displacement meter structure with folding telescopic inductors - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a structure of a displacement meter using an inductor, which uses a folding expansion / contraction inductor instead of a conventional sliding inductor and fits outside an audio excitation wire ring provided on a cylindrical magnetic core. By connecting the one end of the exciting wire ring and one end of the inductor, the other end of the inductor is coupled to the movable body to be displaced, and a folding type expansion and contraction inductor for measuring the displacement of the movable body. It relates to the structure of the displacement meter.
[0002]
[Prior art]
In the conventional displacement gauge structure using a sliding inductor, the other end of the tube forming the sliding inductor is coupled to the movable body, and the sliding movement is made in accordance with the displacement of the movable body from the starting position of the excitation wire ring. In response to the sliding, a change in the excitation current based on the reactance change is caused in the excitation wire ring by electromagnetic induction, and the displacement of the movable body is output as a change in the excitation current.
[0003]
Various types of displacement measurement using the displacement of the inductor as described above have been used.
For example, there is an invention made by the inventors of the present application shown in FIG. 4 (unknown). The present invention is connected to an audible frequency excitation wire ring 52 wound around a magnetic core 50, a protective tube 53 fitted and fixed to the outside thereof, and a displaced movable body (not shown) along the arrow A. The tubular inductor displacement sensor is composed of a tubular sliding inductor 54 that slides on the surface of the protective tube 53, and operates by connecting a connection terminal 56 to an audio power source.
This is simple in structure, robust, and has good output characteristics. However, since the shape requires a space of an equal length with respect to the measured displacement, the effective length ratio to the length is 50% or less. However, if this is used for the displacement sensor of the piston in the cylinder, there is no particular problem in such a case. But if you can't find such a space, you can't use it.
[0004]
Further, there is a spiral inductor sensor shown in FIG. 5 made by the inventors of the present application in order to solve the above problems.
The displacement sensor is a double spiral structure with the winding direction reversed, and uses a spiral inductor that is connected to the terminal and made into a closed circuit. The displacement sensor has a ratio of the total sensor length to the displacement length. The effective length ratio reaches 80 to 90%, and the space can be used very effectively.
[0005]
The displacement sensor is composed of an audio excitation wire ring 60 and a helical inductor 62. The audio excitation wire ring 60 is formed of a two-layer intimate winding wound on a magnetic core 61 and is connected via a terminal 60a. It is configured to operate by being connected to an audio power source not shown.
The spiral inductor 62 is formed of a two-layer winding wire ring composed of an inner layer wire ring 62b and an outer layer wire ring 62a having different winding directions, and the inner layer and the outer layer are respectively wound at the beginning and end of the winding. A closed loop that is electrically coupled and short-circuited at 63 and 65 is formed to short-circuit the voltage induced by the flux linkage.
The fixed end 63a of the spiral inductor 62 is fixed to the terminal end portion O1 of _one terminal of the audio frequency excitation wire ring 60, and the other end of the spiral inductor 62 is displaced to be displaced (not shown). The structure is attached to the movable end of the body, and in use, the spiral inductor 62 is expanded and contracted in the direction indicated by the two-dot chain line in the direction of arrow B as the movable end moves.
The current value corresponding to the reactance change of the audio frequency excitation wire ring 60 corresponding to the expansion / contraction position is read, and the displacement amount is detected.
[0006]
However, when the displacement distance in the horizontal state is long, the central portion of the spiral inductor hangs down, and it is easy to cause contact between the protective tube or the inner and outer spirals.
In the case of the double spiral structure, the inner layer and outer layer coils have different winding directions and are superposed, and when stretched, the inner and outer layer coils are inclined in opposite directions. A loosely coupled structure with a tolerance to move freely is necessary, and the insulation coating of each other may be damaged by the contact of the inner and outer coil strands, especially when the displacement distance of the movable displacement body is large, There is a built-in problem of requiring complicated work for assembly adjustment.
Further, in an environment where vibration is intense, a phenomenon that the spiraling resonates may occur, and the sense of stability is impaired due to the spiraling shape.
[0007]
[Problems to be solved by the invention]
The present invention has been made in view of the above problems,
Providing a structure of a displacement meter with a high-precision foldable expansion and contraction inductor with a high effective length ratio that can reduce the manufacturing cost and assembly cost while configuring a mechanically stable and compact structure. It is the purpose.
[0008]
[Means for solving problems]
Therefore, the structure of the displacement meter by the folding type expansion and contraction inductor of the present invention is as follows:
In the structure of a displacement meter that detects the displacement of a movable body by an inductor that slides on an audio frequency excitation wire ring wound around a magnetic core,
The audio excitation wire ring, and a protective tube made of a non-magnetic material fitted to the outside thereof,
One end of a foldable inductor having a spring function is fixed on the surface of the protective tube at the beginning of the winding of the audio excitation wire ring, and the other end is connected to a movable body to be displaced and expanded and contracted along the protective tube. Configured to cause a change in reactance in the audio frequency excitation wire ring by the expansion and contraction,
Furthermore, the folding inductor having a spring function is formed by alternately folding thin strip-like conductive metal plates having the same thickness, forming a material for each induction element, and providing a through-hole through which the protective tube can pass through each induction element. The through-hole through which the protective tube of the exciting wire ring of the induction element penetrates is an elliptical hole, and its long axis is a folding line that forms each induction element. It is characterized by a vertical direction .
[0009]
The structure of the displacement meter by the folding expansion / contraction inductor of the present invention is as follows.
Concerning the structure of a displacement meter that detects the displacement of a movable body by means of a folding expansion / contraction inductor that slides on a protective tube made of a non-magnetic material fitted on the surface of an audio frequency excitation wire ring wound around a magnetic core so,
The inductor uses a spring-type expandable inductor formed by alternating folding of a metal plate, instead of the conventionally used tubular slip inductor or spiral inductor,
A non-magnetic protective tube fitted outside the audio excitation wire ring is slidably provided through a through-hole, and one end is fixed to the starting position of the audio excitation wire ring and the other end is fixed. By using the foldable expansion / contraction inductor coupled to the displaced movable body and expanding / contracting under a strain stress that is uniformly distributed with respect to the displacement of the movable body, the displacement of the movable body can be accurately expressed as a reactance change of the excitation wire ring. It can be expressed in
[0010]
[0011]
The above-described invention describes the configuration of a folding inductor having a spring function used in the structure of a displacement meter by the folding type inductor of the present invention,
Folding conductive thin strip metal plates alternately to form a material for each inductive element, forming a through-hole through which the protective tube penetrates the material to form each inductive element. By making it penetrate, a retractable inductor is formed.
[0012]
The thickness of each inductive element folded What follow is equal at any portion, when viewed only on a single inductive element portions each inductive elements are foldable attached, they are bound respectively, And the length of the fold line part is designed to be larger than the width of any part parallel to the fold line on the inductive element surface. The induction element elastically deforms and expands and contracts on the protective tube with a uniform strain distribution.
[0013]
Therefore, the minimum reduction length of the foldable expansion / contraction inductor having the above-described configuration, that is, the effective length ratio with respect to the measured total displacement of the thickness of all laminated inductors is extremely high, and it is easy to obtain a value of 95% or more. It is.
When the inductor is fully extended, elastic deformation is performed in the vicinity of the perforation of the inductive element serving as a penetrating portion of the protective tube. When the inductor is fully reduced, each inductor returns to a flat plate shape without bending, and its side surface returns to a straight line.
[0014]
Further, in the structure of the deformation meter by the folding induction element of the present invention,
The through-hole through which the protective tube of the exciting wire ring provided in the induction element passes was an elliptical hole, and the long axis thereof was a direction perpendicular to the fold line forming each induction element .
In other words, the shape of the through hole provided in each induction element that penetrates the protective tube is such that when the inductor is extended, each inductor and the protective tube approach the protective tube and the horizontal inclination angle becomes small.
Therefore, the shape of the through-hole is not circular, but is drilled in an elliptical shape, and the major axis of the elliptical shape is positioned on a vertical bisector that divides the folding line that couples the induction elements approximately vertically. is there.
[0015]
In addition, the thin belt-like plate is folded to form a rectangular folded body, but the corner angle is unnecessary in view of the function as a short-circuit ring of the audio frequency excitation wire ring, and the elastic deformation upper corner angle is cut off, It is desirable to have a shape.
Further, the periphery of the elliptical perforated portion is chamfered to enable smooth sliding on the protective tube surface.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail with reference to the embodiments shown in the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are merely illustrative examples and not intended to limit the scope of the present invention unless otherwise specified. Absent.
FIG. 1 is a diagram showing a schematic configuration of an embodiment relating to the structure of a displacement meter using a folding type expansion / contraction inductor according to the present invention. FIG. 2 (A) is a side view of the inductor when the folding type inductor of FIG. 1 is extended. In the figure, (B) is a IIIB-IIIB view of (A). FIG. 3 is a diagram showing a characteristic curve of the folding type expansion and contraction inductor of FIG.
[0017]
In FIG. 1, a displacement gauge structure using a folding expansion / contraction inductor is closely connected to a cylindrical magnetic core 11 and is excited by an audio frequency power source (not shown), and The non-magnetic protective tube 13 fitted to the outer peripheral portion over the entire length, the folding expansion / contraction inductor 10 that loosely slidably fits the surface of the protective tube 13, and the displaced movable body 14,
One end 10 a of the folding expansion / contraction inductor 10 is fixed to the starting start end of the excitation wire ring 12 at the left end of the protective tube 13, and the other end 10 b is attached to the movable end of the displaced movable body 14.
As the movable body 14 to be displaced is displaced in the direction of arrow A, the foldable expansion / contraction inductor 10 extends in the direction of arrow A through the other end 10b.
[0018]
The foldable expansion / contraction inductor 10 is formed of a conductive thin elastic member, for example, a phosphor bronze plate or a copper plate with increased hardness,
As shown in FIG. 2 (A), the band-shaped member is sequentially folded into a rectangular shape having a length S equivalent to the width of the member in the flow direction C of the member via a folding line 10c, An elliptical through-hole 15 having a vertical bisector of the folding line 10c as a major axis is drilled in the center (forming the material of each inductor element) and laminated in a stretchable tension spring shape. As shown in (B), an inductive element group having a length S on one side is formed.
[0019]
The through-hole 15 is provided at the center of the square-shaped piece, and has a hole diameter through which the nonmagnetic protective tube 13 fitted over the entire surface of the audio excitation wire 12 can pass through in a loose fit. In this case, it is necessary for the inductor to be easily slidable and expandable on the outer peripheral surface of the protective tube 13. For example, when the inductor is sufficiently extended, the respective rectangular induction elements are inclined in opposite directions. In consideration of the above, the through hole 15 is configured to have an elliptical shape.
[0020]
As shown in FIG. 2 (B), the rectangular corner portion 17 that is not particularly necessary for the function of the inductive element group can be cut off into an octagonal shape so as to have an elastic function on each inductive element surface.
Note that chamfering to the inner peripheral thickness of the elliptical perforations is necessary because the horizontal inclination angle with respect to the protective tube 13 is reduced when the inductor is extended, and thus the inductor 10 smoothly slides against the protective tube 13. It is possible to move.
[0021]
Such expansion and contraction of the inductor 10 changes the reactance of the audio frequency excitation wire ring 12, and the change enables the displacement of the displaced movable body 14 to be measured.
In other words, in the inductor 10, the folded rectangular piece has a rectangular shape because the protective tube 13 that fits the outside of the exciting wire ring 12 passes through the through hole 15 that is perforated. A short-circuit ring of the exciting wire ring 10 is formed on the folded piece, and constitutes an expandable / contractible inductive element coupled via a folding portion.
Therefore, the double helix type inductor described above has a different structure from that formed by connecting both ends of two spirally wound coils in order to form a closed circuit. The inductor of the present application is formed by an assembly in which are joined at the folding part.
[0022]
Contact name is equal in foldable been thicknesses any part of the inductive element, when viewed only on a single inductive element portions each inductive element has been folded and bound, deflection occurs in the inductive element surface The folded induction element 10 is elastically deformed on the protective tube 13 over the entire area under a uniform strain distribution and can be expanded and contracted. Therefore, the induction element 10 has high accuracy corresponding to the displacement of the variable displacement movable body. An output change corresponding to the reactance change can be obtained.
[0023]
FIG. 3 shows a characteristic curve of the inductor of the present application.
In the figure, the displacement of the movable body to be displaced is plotted on the horizontal axis, and the amount of current change in the audio frequency excitation wire is plotted on the vertical axis. As shown in the figure, the output characteristics with respect to the displacement of the fixed portion of the terminal of the inductor has a non-linear correction effect because the inductor is stacked, and exhibits a linear characteristic except for the terminal portion of the movable end. And its accuracy is excellent.
[0024]
【The invention's effect】
The present invention has the following effects by the above configuration.
a. By using a folding inductor, a compact configuration that does not require a retrace line that closes the induction wire ring by forming an assembly of inductive elements having independent short-circuit rings, that is, a short-circuit portion, can be obtained.
b. Since the expansion and contraction of the inductor is due to the elasticity of the flat portion of the inductive element surface, it does not fatigue and break even for long-term operation, and responds to the displacement of the displaced movable body with a uniform strain distribution. And stable measurement results can be obtained.
c. Maintains elasticity even against vibrations in the surrounding environment of the measuring instrument and has seismic characteristics.
d. High productivity and small size.
e. Since the effective length ratio is extremely high, the utilization rate is high even in a narrow space.
f, Output characteristics are stable.
[Brief description of the drawings]
FIG. 1 is a diagram showing a schematic configuration of an embodiment relating to the structure of a displacement meter using a folding type expansion and contraction inductor according to the present invention.
2A is a side view of the inductor when the folding inductor of FIG. 1 is extended, and FIG. 2B is a view taken along the line IIIB-IIIB of FIG.
FIG. 3 is a diagram showing a characteristic curve of the folding type expansion / contraction inductor of FIG. 1;
FIG. 4 is a diagram showing a schematic configuration of a conventional tubular inductor displacement sensor.
FIG. 5 is a diagram showing a schematic configuration of a conventional helical inductor displacement sensor.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Folding type | mold expansion-contraction inductor 10a One end 10b The other end 10c Folding line 11 Cylindrical magnetic core 12 Audio excitation wire ring 13 Nonmagnetic protective tube 14 Displaceable movable body 15 Through-hole 17 Square corner

Claims (1)

In the structure of a displacement meter that detects the displacement of a movable body by an inductor that slides on an audio frequency excitation wire ring wound around a magnetic core,
The audio excitation wire ring, and a protective tube made of a non-magnetic material fitted to the outside thereof,
One end of a foldable inductor having a spring function is fixed on the surface of the protective tube at the beginning of the winding of the audio excitation wire ring, and the other end is connected to a movable body to be displaced and expanded and contracted along the protective tube. Configured to cause a change in reactance in the audio frequency excitation wire ring by the expansion and contraction,
Furthermore, the folding inductor having a spring function is formed by alternately folding thin strip-like conductive metal plates having the same thickness, forming a material for each induction element, and providing a through-hole through which the protective tube can pass through each induction element. The through-hole through which the protective tube of the exciting wire ring of the induction element penetrates is an elliptical hole, and its long axis is a folding line that forms each induction element. A structure of a displacement meter using a folding expansion / contraction inductor, characterized by having a vertical direction .

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