JP2005147675A - Tension sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a tension sensor in a simple structure that can be manufactured easily and can detect a tension change precisely with high sensitivity. <P>SOLUTION: The tension sensor 10 comprises a nearly cylindrical supermagnetostrictive member 18, and a transmission member 20 composed of a flat body 20A that is arranged in contact with one end face 18B in an axial direction L of the giant magnetostrictive member 18, and a rod-like body 20B provided through an inner space 18A in the supermagnetostrictive member 18 with the flat body 20A as a base end. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a tension sensor that detects tension using a magnetostrictive member.

  2. Description of the Related Art Conventionally, a “biliary effect” that a change occurs in the magnetic permeability of a member when stress is applied to the magnetostrictive member is widely known, and various tension sensors using the principle of this “bilari effect” have been proposed.

  For example, a conventionally known tension sensor 1 shown in FIG. 6 is fixed to two tension rods 2A and 2B, and is slidable in the sensor chamber 4 of the sensor housing 3, and the plunger 5 A columnar barrier effect sensor 7 disposed between the provided spring 6 and the sensor housing 3 is provided (see Patent Document 1).

  The tension sensor 1 is structured such that when the sensor housing 3 is moved by tension, the billiary effect sensor 7 receives an axial compressive force, and a change in the permeability of the billiary effect sensor 7 based on the compressive force is detected by a coil. By detecting with (not shown) or the like, a change in tension applied to the tension sensor 1 can be detected.

Japanese translation of PCT publication No. 2002-513475

  However, in order to increase the detection sensitivity of the tension change in the tension sensor 1, it is necessary to uniformly transmit the tension applied to the sensor housing 3 to the barrier effect sensor 7 without being biased. For that purpose, it is necessary to attach one end side of the billiary effect sensor 7 to the axial center position of the housing 3 with high accuracy and attach the other end side to the center equivalent position of the two tension rods 2A, 2B with high accuracy. There is a problem that the manufacturing becomes extremely difficult.

  The present invention has been made to solve such problems, and provides a tension sensor having a simple structure that can detect a change in tension with high accuracy and high sensitivity while being easy to manufacture. For the purpose.

  As a result of research, the inventors of the present invention have found a tension sensor having a simple structure that can detect a change in tension with high accuracy and high sensitivity while being easy to manufacture.

  That is, the above-described object can be achieved by the following present invention.

  (1) A substantially cylindrical magnetostrictive member, a plate-like body arranged in contact with one end face in the axial direction of the magnetostrictive member, and the plate-like body as a base end to penetrate through the inner space of the magnetostrictive member A tension member comprising: a transmission member configured by a bar-shaped body formed.

  (2) The magnetostrictive member has a cylindrical shape, and the plate-like body in the transmission member has a disc shape having the same outer diameter as one end surface in the axial direction of the magnetostrictive member. (1) The tension sensor according to the above.

  (3) The tension sensor according to (1) or (2), wherein a preload can be applied in an axial direction of the magnetostrictive member.

  (4) The tension sensor according to any one of (1) to (3), wherein the magnetostrictive member is a giant magnetostrictive member made of a giant magnetostrictive element.

  The tension sensor having a simple structure according to the present invention has an excellent effect that a change in tension can be detected with high accuracy and high sensitivity while being easily manufactured.

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

  As shown in FIGS. 1 and 2, the tension sensor 10 according to the embodiment of the present invention includes a box-shaped case 12 made of a nonmagnetic material, and the case 12 includes a plurality of fixing screws 14 (one Only the part is shown) and is fixed on the base plate 16.

  Further, in the case 12, a cylindrical super magnetostrictive member 18, a transmission member 20 disposed in the inner space 18 </ b> A of the super magnetostrictive member 18, and a disc spring 22 disposed above the transmission member 20. And a pickup coil 24 disposed so as to surround the outer periphery of the giant magnetostrictive member 18 is accommodated.

  Further, a preload screw 26 capable of applying a preload in the axial direction L of the giant magnetostrictive member 18 is attached to the upper portion of the case 12 via a disc spring 22, thereby preliminarily applied to the giant magnetostrictive member 18. The load can be adjusted. The preload by the preload screw 26 is set to an optimum value according to the specifications of the tension sensor 10 (described later).

  The transmission member 20 includes a plate-like body 20A having a disc shape and a rod-like body 20B. The plate-like body 20A is disposed in contact with the one end face 18B in the axial direction L of the giant magnetostrictive member 18, and has the same outer diameter as the one end face 18B. Further, the rod-like body 20B is provided so as to penetrate through the inner space 18A of the giant magnetostrictive member 18 with the plate-like body 20A as a base end, and the distal end portion projects out of the case 12.

  The giant magnetostrictive member 18 uses a giant magnetostrictive element as a material. Here, the “super magnetostrictive element” is a magnetostrictive element made of a powder sintered alloy or a single crystal alloy containing a rare earth element and / or a specific transition metal as a main component (for example, terbium, dysprosium, iron, etc.). Say. This (super) magnetostrictive element has a characteristic that causes a large change in magnetic permeability (or residual magnetization) when deformed by receiving stress from the outside. That is, when the (super) magnetostrictive element is stretched by receiving a tensile force, the magnetic permeability is increased, and when the (super) magnetostrictive element is contracted by a compressive force, the magnetic permeability is decreased.

  The pickup coil 24 can detect a change in magnetic permeability or residual magnetization caused by the deformation of the giant magnetostrictive member 18 as a change in inductance of the pickup coil 24.

  Next, the operation of the tension sensor 10 will be described.

  When the tension F is applied to the transmission member 20 of the tension sensor 10, a compressive force in the axial direction L is applied to the one end face 18 </ b> B of the giant magnetostrictive member 18 via the plate-like body 20 </ b> A of the transmission member 20. The super magnetostrictive member 18 is deformed by the compressive force from the transmission member 20, and the super magnetostrictive member 18 expands in the radial direction and contracts in the axial direction. As a result, the volume of the giant magnetostrictive member 18 occupying the inner space of the pickup coil 24 changes, and the permeability or residual magnetization of the giant magnetostrictive member 18 changes. Therefore, a change in the tension F applied to the transmission member 20 can be detected by detecting this change in magnetic permeability or residual magnetic susceptibility as a change in inductance value of the pickup coil 24.

  As shown in FIG. 3, the inventors of the present invention have not applied a preload to the giant magnetostrictive member 18 with respect to the relationship between the tension F and the inductance value I of the pickup coil 24 (FIG. 3 ( A)), three kinds of data were collected when a preload of 50 kgf was applied (FIG. 3B) and when a preload of 100 kgf was applied (FIG. 3C). In this example, an element having an outer diameter of 10 mm, an inner diameter of 6 mm, and a length of 6 mm is used as the giant magnetostrictive member 18.

  Then, the values of X, Y, and Z shown in FIG. 4 are measured for the above three types of data, and based on the measured values X, Y, and Z, linearity (Y / X) and hysteresis (Z / X ) Values were compared. As a result, as shown in the table of FIG. 5, in this example, it was found that the linearity and the hysteresis characteristics were the best when a preload of 100 kgf was applied.

  According to the tension sensor 10 of the present invention, the substantially cylindrical super magnetostrictive member 18, the plate-like body 20 </ b> A disposed in contact with the one end face 18 </ b> B in the axial direction L of the super-magnetostrictive member 18, and the plate-like body 20A as a base end, and the transmission member 20 constituted by the rod-like body 20B provided through the inside space 18A of the giant magnetostrictive member 18, the structure is extremely simple and easy to manufacture. In addition, the tension applied to the transmission member 20 can be uniformly transmitted to the giant magnetostrictive member 18 without deviation, and a change in tension can be detected with high accuracy and high sensitivity.

  In particular, since the giant magnetostrictive member 18 has a cylindrical shape, and the plate-like body 20A of the transmission member 20 has a disc shape having the same outer diameter as the one end face 18B in the axial direction L of the giant magnetostrictive member 18, The tension applied to the transmission member 20 can be efficiently transmitted to the giant magnetostrictive member 18, and a change in tension can be detected with higher accuracy and sensitivity.

  In addition, since a preload can be applied in the axial direction L of the giant magnetostrictive member 18 by the preload screw 26, if the preload is adjusted according to the specifications of the tension sensor 10, characteristics of tension detection (linearity and hysteresis) Characteristics) can be optimally designed.

  The tension sensor according to the present invention is not limited to the structure, shape, and the like of the tension sensor 10 according to the above embodiment. For example, the giant magnetostrictive member 18 is not in a cylindrical shape, but in a rectangular tube shape or the like. Also good. Further, the plate-like body 20 </ b> A of the transmission member 20 is not limited to a disk-shaped member having the same outer diameter as the one end face 18 </ b> B in the axial direction L of the giant magnetostrictive member 18. Further, when it is not necessary to increase the detection sensitivity so much, a magnetostrictive member made of a magnetostrictive element may be applied instead of the super magnetostrictive member 18, and when a desired tension detection characteristic can be obtained, a preload is applied. The screw 26 may not be attached.

  That is, a substantially cylindrical magnetostrictive member, a plate-like body arranged in contact with one end surface in the axial direction of the magnetostrictive member, and the inside of the magnetostrictive member through the plate-like body as a base end are provided. Any tension sensor may be used as long as it has a transmission member constituted by a rod-shaped body.

  In the above embodiment, the pickup coil 24 is applied as a detecting means for detecting a change in the magnetic permeability of the giant magnetostrictive member 18, but the present invention is not limited to this. Therefore, for example, a magnetoresistive effect element such as MR, GMR, or TMR or a Hall element may be applied as the detecting means, and a change in magnetic permeability may be detected as a change in electromotive force of the magnetoresistive effect element or the Hall element.

Schematic side sectional view showing a tension sensor according to an embodiment of the present invention Schematic cross-sectional view along line II-II in FIG. The tension and the inductance of the pickup coil when no preload is applied to the giant magnetostrictive member in FIG. 1 (A), when a preload of 50 kgf is applied (B), and when a preload of 100 kgf is applied (C) Graph showing the relationship Graph showing measured values X, Y, and Z that serve as a basis for linearity and hysteresis Table showing the relationship between measured values X, Y, Z, linearity and hysteresis for preload applied to giant magnetostrictive member Schematic side sectional view showing a conventional tension sensor

Explanation of symbols

F ... Tension I ... Inductance 1, 10 ... Tension sensor 2A, 2B ... Tension rod 3 ... Sensor housing 4 ... Sensor chamber 5 ... Plunger 6 ... Spring 7 ... Billing effect sensor 12 ... Case 14 ... Fixing screw 16 ... Base plate 18 ... Giant magnetostrictive member 18A ... inner space 18B ... one end face in the axial direction 20 ... transmission member 20A ... plate-like body 20B ... rod-like body 22 ... disc spring 24 ... pickup coil 26 ... preload screw

Claims (4)

  A substantially cylindrical magnetostrictive member, a plate-like body disposed in contact with one axial end surface of the magnetostrictive member, and a rod-like shape provided through the inside space of the magnetostrictive member with the plate-like body as a base end A tension sensor comprising: a transmission member constituted by a body. In claim 1,
The tension sensor according to claim 1, wherein the magnetostrictive member has a cylindrical shape, and the plate-like body of the transmission member has a disc shape having the same outer diameter as one axial end surface of the magnetostrictive member. In claim 1 or 2,
A tension sensor characterized in that a preload can be applied in the axial direction of the magnetostrictive member. In any one of Claims 1 thru | or 3,
A tension sensor comprising the magnetostrictive member made of a giant magnetostrictive member made of a giant magnetostrictive element.

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