JP2006275796A - Fastener and its use - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To measure the fixing forces of various types of fasteners in real time. <P>SOLUTION: A washer 1 is provided with a stress luminescent body 2 which indicates emission intensity according to the magnitude of given mechanical distortion. By measuring emission intensity from the stress luminescent body 2, it is possible to accurately measure the fixing force of the washer 1 to an object. Since the stress luminescent body 2 can be provided for a fastener by application even if the washer 1 has any shape, it is possible to easily measure the fixing forces of various washers 1 to an object. Since the stress luminescent body 2 instantaneously emits light when an external force is applied, it is possible to measure the fixing force of the washer 1 in real time. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a fastener for fixing an object. Further, the present invention relates to a fixing force measuring device and a fixing force measuring method for measuring a force with which the object is fixed by the fastener, and for fastening the fastener. The present invention relates to a fastener fastening device, a fastener manufacturing method, and a fixing method using the fastener.

  Since screw parts are versatile enough to be applied to all types of machines, vehicles, power engines, and buildings, it is no exaggeration to say that they are used in almost all machine products and woodwork products. .

  Screw parts include various materials and shapes. Generally, screw parts are used as fasteners for fastening an object such as nuts, washers, and bolts.

  If a screw part used as a fastener is defective, the force for tightening the object cannot reach a predetermined value, which may lead to a serious accident. In fact, disasters such as aircraft accidents, plant explosions, gas and oil leakage accidents, and vehicle accidents are often caused by just one screw. Therefore, in order to prevent such an accident, it is necessary to manage an appropriate tightening force of the screw.

  Various attempts have been made to solve such problems. For example, there is a method of tightening a screw component to a predetermined torque by detecting a tightening torque of the screw component. For example, a torque driver, a torque wrench, a torque spanner, or the like is used as a tightening device capable of detecting the tightening torque.

  However, even if the tightening torque reaches a predetermined value, the fixing force of the bolt or screw does not become predetermined.

  That is, the tightening torque depends on both the coefficient of friction and the axial force of the screw part. Therefore, if there is some defect in the screw component or if dust or dirt is attached to the surface, if the frictional force becomes abnormally large, the tightening torque may become a predetermined value even if the axial force is small.

  The axial force is the most important value for evaluating the force for fixing the object (fixing force) in the tightening with the screw component. If this fixing force is insufficient, the screw parts cannot play the role of a fastener, which may lead to a major accident. At present, for example, an axial force meter and an axial force management system using ultrasonic waves have been developed in order to evaluate a fixing force by a screw component (see Patent Documents 1 to 7).

In addition, the excitation coil is configured to generate vibration and transmit the vibration to the bolt. The resonance frequency of the bolt is obtained by changing the frequency of the excitation coil, and the bolt axial force is measured from this resonance frequency. The apparatus which performs is proposed (refer patent document 8, 9).
JP 2000-141241 (released May 23, 2000) JP 2004-108910 (April 8, 2004) JP 06-088758 (published March 29, 1994) JP 2004-156992 (released on June 3, 2004) JP 2004-093362 (released on March 25, 2004) JP 2003-227768 (released on August 15, 2003) JP 2004-114182 (April 15, 2004) JP-A-2004-279207 (released on October 7, 2004) JP 2004-226413 (released on August 12, 2004) JP 2000-119647 (April 25, 2000) JP 2000-313878 (released on November 14, 2000) JP 2001-049251 (released February 20, 2001) JP 2002-194349 (released July 10, 2002) JP2003-292949 (released on October 15, 2003) JP 2004-043656 (published on February 12, 2004) JP2003-253261 (released September 10, 2003) JP2004-071511 (published March 4, 2004) JP 2004-149738 (released May 27, 2004)

  However, when evaluating the fixing force of screw parts using ultrasonic waves, the axial force is managed by calculating the difference in ultrasonic propagation time before and after tightening to the elongation value of the bolt. Furthermore, it can be used only for screw parts of limited materials (steel, etc.) and sizes (diameter of 10 mm or more), and it is difficult to manage the fixing force of many screw parts in real time. Also, it is impossible to detect the occurrence of defects due to vibration during use. Even when the axial force is managed using the resonance frequency, it is difficult to manage the axial force in real time. Furthermore, even when screw parts are tightened from the elastic region to the plastic region, it has been conventionally required to properly manage the fixing force of the screws.

  Various materials are used for screw parts. For example, metal and plastic are mainly used. As the metal, iron, stainless steel, brass (brass), copper, aluminum alloy, titanium alloy, etc. are used. As the plastic, acrylic, Teflon (registered trademark), FRP, bakelite, polycarbonate, Reny, etc. are used. . Furthermore, materials such as ceramics are used for screw parts for special purposes. There are also many plated screw parts.

  Furthermore, there are various screw shapes. For example, the shape of the head of the screw includes a flat head, a round head, a pan head, a round head, a binding head, a truss head, a pleasure head, a cheese head, a flat head, a round flat head, a hexagonal head, and a square head. Further, a special shape may be processed on the head of the screw in order to insert or hook a tool when the screw is tightened. There are many such shapes such as cross holes, slits, and hexagon holes. There are also a great variety of screw sizes and pitches.

  As described above, a large number of screw parts are used in almost all devices, machines, structures, and the like, and there are various types. Therefore, parts and methods that can detect the fixing force with an inexpensive and simple method are required. Also, not only for screw parts, but also for fasteners that fix an object by generating axial force, such as rivets and pins, parts and methods that can detect the fixing force with an inexpensive and simple method are required. is there.

  The present invention has been made in view of the above-described conventional problems, and is a fastener, a fixing force measuring device, and a fastener that can measure the fixing force of various shapes of fasteners from an elastic region to a plastic region in real time. It is an object of the present invention to provide a fastening device, a fastener manufacturing method, a fixing method, and a fixing force measuring method.

  In order to solve the above-described conventional problems, the fastener of the present invention is characterized by including a stress-stimulated illuminant that exhibits luminescence intensity corresponding to the magnitude of mechanical strain applied.

  According to the above configuration, the fastener includes the stress illuminant, and further shows the luminescence intensity according to the magnitude of mechanical strain to which the stress illuminant is applied, so the luminescence intensity from the stress illuminant is measured. By doing so, the magnitude of the force generated in the fastener can be measured.

  Here, the fastener is used for fixing an object by generating a force such as a tensile force or a frictional force therein. That is, it can be said that the magnitude of the force generated inside the fastener is the most accurate value for evaluating the fixing force for fixing the object. Therefore, by measuring the light emission intensity from the stress light emitter, the force with which the fastener fixes the object can be measured accurately.

  In addition, since the stress illuminant can be provided on the fastener by application, mixing with the fastener material, etc., regardless of the shape of the fastener, the object with various fasteners is fixed. Force can be measured easily. Further, since the stress light emitter emits light instantaneously when an external force is applied, the fixing force by the fastener can be measured in real time.

  In addition, the amount of strain applied to the fastener of the present invention varies depending on the amount of stress generated in the material, regardless of whether the material applying the strain is an elastic region or a plastic region. To do. And the stress light-emitting body with which the fastener of this invention is equipped light-emits according to the magnitude | size of the given mechanical distortion.

  That is, it can be said that the fastener of the present invention exhibits a light emission intensity corresponding to the magnitude of the stress generated in the material that distorts the fastener. Therefore, according to the fastener of the present invention, the fixing force from the elastic region to the plastic region can be managed.

  Furthermore, the fastener of the present invention is preferably a washer. This is because a washer as a fastener is used in almost all cases when an object is fixed using a screw. Therefore, by realizing the fastener of the present invention as a washer, the fixing force in almost all fastening structures can be accurately measured. Moreover, also when fixing a target object using the existing volt | bolt and nut, the fixing force by a volt | bolt and a nut can be evaluated by using the washer which concerns on this invention.

  Further, the stress-stimulated luminescent material is preferably applied to the entire surface of the washer. The inventors of the present invention have confirmed by experiments that when the stress-stimulated luminescent material is applied to the entire washer, the luminescence intensity of the stress-stimulated luminescent material increases when the fixing force is equal to or greater than the threshold value. Therefore, according to the fastener having the above-described configuration, it is possible to accurately evaluate whether the object is fixed with a fixing force equal to or greater than a predetermined value. The predetermined value can be adjusted by selecting the type of coating.

  The stress-stimulated luminescent material is preferably formed so that the side surface of the washer extends in the axial direction of the washer, and connects both end surfaces of the washer. The present inventors have confirmed that when the stress-stimulated luminescent material is applied to the washer as described above, the stress-stimulated luminescent material emits light with the highest intensity. If the stress-stimulated luminescent material emits light with strong intensity in this way, the light can be easily detected by an optical sensor or the like. Therefore, according to the fastener of the said structure, the force with which the target object is being fixed by the fastener can be evaluated accurately.

  In addition, even if the sulfide, nitride, oxide, selenide, or telluride contained in the stress luminescent material has a wurtzite structure or a spinel structure, the stress luminescent material reacts sensitively to friction. It is known to emit light. Therefore, by providing such a stress-stimulated luminescent material on a fastener such as a washer, the fixing force by the fastener can be accurately evaluated.

Furthermore, the stress-stimulated luminescent material preferably contains ZnS or ZnAl ₂ O ₄ . This is because it is known that a stress-stimulated luminescent material containing ZnS or ZnAl ₂ O ₄ reacts sensitively to light and emits light. Therefore, by providing a stress light emitter containing ZnS or ZnAl ₂ O ₄ on a fastener (such as a washer) that fixes an object by a frictional force, the fixing force by the fastener can be accurately evaluated.

  The fastener of the present invention may be a bolt or a nut. This is because bolts and nuts as fasteners are used in almost all cases when fixing an object using screws. Therefore, by realizing the fastener of the present invention as a bolt, the fixing force in almost all fastening structures can be accurately measured.

  Furthermore, many fasteners, such as bolts, fix an object by generating a tensile force inside. A strontium aluminate-based stress luminescent material is known as a stress luminescent material that reacts sensitively to a tensile force and emits light.

  Therefore, by using a strontium aluminate-based stress luminescent material as the stress luminescent material, it is possible to accurately evaluate the fixing force of the fastener that fixes the object using the tensile force generated inside.

  Further, in order to measure the bolt tightening axial force, it is effective to apply the stress light emitter in a thin line extending in the axial direction. When the stress luminescent material is applied in this manner, the bolt is less likely to be distorted in the radial direction, so that the distortion in the axial direction of the bolt can be accurately grasped from the light emission intensity of the stress luminescent material.

  On the other hand, in order to measure the tightening axial force of the bolt, it is effective to apply the stress light emitter in a thin line extending in the radial direction. When the stress luminescent material is applied in this manner, the bolt is less likely to be distorted in the axial direction, so that the distortion in the radial direction of the bolt can be accurately grasped from the luminescence intensity of the stress luminescent material.

  The fixing force measuring device of the present invention measures the force with which the object is fixed by the fastener in order to solve the conventional problem, and the fastener is subjected to mechanical distortion. And a light intensity measuring means for measuring the intensity of the light emitted by the stress light emitter.

  According to the fixing force measuring apparatus having the above-described configuration, the force with which the fastener fixes the object can be accurately and real-time plastically from the elastic region without questioning what shape the fastener has. It is possible to measure to the range.

  Further, according to the fastener fastening device including the fixing force measuring device and the fastening means configured as described above, the fastener can be tightened while accurately managing the fixing force by the fastener in real time. It can be securely and securely fixed.

  In addition, in order to solve the above-described conventional problems, the fastener manufacturing method of the present invention is to apply a stress illuminant having a light emission intensity corresponding to the magnitude of mechanical strain applied to the surface of the fastener. It is a feature. Furthermore, the fastener manufacturing method of the present invention may be characterized by mixing a raw material of a stress-stimulated illuminant exhibiting a light emission intensity corresponding to the magnitude of mechanical strain applied and a raw material of the fastener.

  According to the fastener manufacturing method of the said structure, the fastener provided with the stress light-emitting body which shows the light emission intensity according to the magnitude | size of the mechanical distortion given can be manufactured. Therefore, it is possible to provide a fastener capable of evaluating the fixing force from the elastic region to the plastic region accurately and in real time.

  In addition, in order to solve the above-described conventional problems, the fixing method of the present invention uses a fastener including a stress illuminant that exhibits luminescence intensity according to the magnitude of mechanical strain to be applied. It is characterized by fixing.

  According to the fixing method, since the fastener according to the present invention is used, it is possible to accurately measure the force with which the fastener fixes the object, and the fixing force by the fastener is elastic in real time. It is possible to measure from the region to the plastic region.

  In addition, the fixing force measuring method of the present invention is a fixing force measuring method for measuring a force with which an object is fixed by a fastener, in order to solve the above-described conventional problems, And a stress illuminant having a light emission intensity corresponding to the magnitude of mechanical strain, and measuring the intensity of light emitted from the stress illuminant.

  According to the above configuration, it is possible to measure the force with which the fastener fixes the object accurately and in real time from the elastic region to the plastic region without questioning what shape the fastener has. it can.

  According to the fastener of the present invention, it is possible to accurately measure the force with which the fastener fixes the object by measuring the light emission intensity from the stress light emitter. Moreover, since the stress illuminant can be provided on the fastener by application regardless of the shape of the fastener, the force for fixing the object by various fasteners can be easily measured. Can do. Further, since the stress light emitter emits light instantaneously when an external force is applied, the fixing force by the fastener can be measured in real time.

[1. (Configuration of fasteners)
Embodiments of the fastener of the present invention will be described below. The embodiment of the fastener described below is common in that a stress illuminant that emits light when mechanical external force is applied is applied to the surface of the fastener, and the light emission intensity of the stress illuminant is The fixing force is evaluated based on this.

(1-1. Washer)
First, a washer as an embodiment of a fastener according to the present invention will be described. As shown in FIG. 1A, the washer 1 of the present embodiment is coated with a stress-stimulated luminescent material 2 with a thickness of about 10 microns on the entire surface. Further, as shown in FIG. 1B, a groove having a depth of about 1 mm may be formed on the side surface of the washer 1, and the stress light emitter 2 may be formed so as to fill the groove. As a result, the stress-stimulated luminescent body 2 is formed so that the side surface of the washer 1 extends in the axial direction of the washer 1, and the end surface 1a and the end surface 1b of the washer 1 are connected.

  Moreover, although the groove | channel formed in the washer 1 shown in FIG.1 (b) is formed so that the washer 1 may be penetrated to an axial direction, it is not necessarily required. That is, as shown in FIG. 1C, the stress light emitter 2 may be formed so as to fill a groove formed from the end surface position to the intermediate position in the axial direction of the washer 1. Furthermore, as shown in FIG. 1 (d), the stress-stimulated luminescent material 2 may be embedded only in the vicinity of the middle in the axial direction of the washer 1. In short, a portion where the stress light emitter 2 is exposed from the surface of the washer 1 may be present so that light emitted from the stress light emitter 2 is not blocked inside the washer 1.

  By integrally forming the washer 1 and the stress light emitter 2 in this way, the stress light emitter 2 emits light according to the axial force generated in the washer 1. Since the stress illuminant 2 exhibits a light emission intensity corresponding to the magnitude of mechanical strain, the axial force generated in the washer 1 is measured by measuring the intensity of light emitted from the stress illuminant 2. Is possible.

  And it goes without saying that the axial force generated in the washer 1 can be evaluated as a fixing force when the washer 1 is used as a fastener. Therefore, when the object is fixed using the washer 1 of the present embodiment, the fixing force by the washer 1 can be measured by measuring the emission intensity from the washer 1.

  In the configuration shown in FIG. 1C and FIG. 1D, most of the surfaces 1a and 1b with which the washer 1 contacts the fixed object are formed of the material of the washer 1. Therefore, when the object is fixed using the washer 1, the frictional force between the washer 1 and other fasteners such as bolts and nuts, or the frictional force between the washer 1 and the fixed object is changed. There is no. Therefore, from the viewpoint of obtaining a stable fixing force, it can be said that the washer having the configuration shown in FIGS. 1C and 1D is preferable.

  Moreover, although the case where the washer 1 was a flat washer was demonstrated in this embodiment, the washer which can apply this invention is not limited to a flat washer. For example, the present invention is applicable to a square washer and a spring washer.

(1-2. Nut)
Next, a nut as another embodiment of the fastener according to the present invention will be described. As shown in FIG. 2A, the hexagon nut 3 of the present embodiment is formed so that the stress light emitter 2 is embedded in grooves formed on each of the six side surfaces of the hexagon nut 3. The depth and size of the groove can be arbitrarily set.

  Further, as shown in FIG. 2B, an annular groove may be formed in the vicinity of the center position in the axial direction of the side surface of the hexagon nut 3, and the stress light emitter 2 may be embedded in the groove. . Further, as shown in FIG. 2 (c), the stress light emitter 2 may be formed on the entire surface of the hexagon nut 3. In short, a portion where the stress light emitter 2 is exposed from the surface of the hexagon nut 3 may be present so that light emitted from the stress light emitter 2 is not blocked inside the hexagon nut 3.

  Thus, by integrally forming the hexagon nut 3 and the stress light emitter 2, when the object is fixed using the hexagon nut 3, the stress light emitter 2 emits light by the fixing force. Therefore, it goes without saying that the fixing force can be measured as in the case where the washer 1 and the stress light emitter 2 are integrally formed.

  In addition, in this embodiment, although the case where a nut was a hexagon nut was demonstrated, the nut which can apply this invention is not limited to a hexagon nut. For example, the present invention can be applied to various nuts such as a cap nut and a wing nut.

(1-3. Bolt)
Next, a bolt as still another embodiment according to the present invention will be described. As shown in FIG. 3A, the bolt 4 of this embodiment is applied in a strip shape so that the stress-stimulated luminescent material 2 extends in the circumferential direction of the shaft portion. Further, as shown in FIG. 3B, the stress-stimulated luminescent material 2 may be applied in a strip shape so as to extend in the axial direction of the bolt 4 in the shaft portion of the bolt 4.

  Thus, by integrally forming the bolt 4 and the stress light emitter 2, when the object is fixed using the bolt 4, the stress light emitter 2 emits light by the tightening axial force (fixing force). Therefore, the fixing force by the bolt 4 can be measured by measuring the light emission intensity of the stress light emitter 2.

  In particular, the part of the bolt to which the stress-stimulated luminescent material 2 is applied is preferably a part where a tensile force is applied to the bolt during tightening, as shown in FIGS. 3 (a) and 3 (b). This is because the bolt can be tightened without changing the frictional force between the bolt and the washer or the frictional force between the bolt and the fixed object.

  3A and 3B illustrate the case where the head of the bolt 4 is a hexagon, the bolt to which the present invention can be applied is also a bolt having a square head. It can be applied, and can also be applied to a bolt without a head, such as an implanted bolt.

  Moreover, as a washer used for the volt | bolt 4 of this embodiment, as shown in FIG.3 (c), the thing in which the notch 5 was formed is good. This is because the light emitted from the stress-stimulated luminescent material 2 can pass through the notch 5 and reach the outside. By measuring the intensity of light reaching the outside, the fixing force by the bolt 4 can be measured.

(1-4. Applicable stress light emitter)
Furthermore, specific examples of substances that can be used as the stress-stimulated luminescent material 2 of the present embodiment will be described below. Stress light emitters are substances that emit light by mechanical action, and those that emit light by friction, those that emit light by destruction, those that emit light by plastic deformation, and those that emit light by elastic deformation have been developed. In particular, inorganic stress luminescent particles that have recently been developed by the inventors of the present invention are suitable for use as the stress luminescent material 2.

  For example, the following substances (1) to (8) can be used as the stress-stimulated luminescent material 2.

(1) Stress light-emitting material having a spinel structure, a corundum structure, or a β-alumina structure (see Patent Document 10)
(2) Stress-luminescent material of silicate (see Patent Document 11)
(3) Defect control type aluminate high intensity stress illuminant (see Patent Document 12)
(4) Multicolor-type stress luminescent material (see Patent Document 13)
(5) Composite material with epoxy resin (see Patent Document 14)
(6) Stress-stimulated luminescent material composed mainly of oxide, sulfide, selenide, and telluride having a structure in which a wurtzite structure and a zincblende structure coexist (see Patent Document 15)
(7) Europium-added strontium aluminate exhibiting stress luminescence, polymethacrylate, ABS resin, polycarbonate, polystyrene, polyethylene, polyacetal, urethane resin, polyester, epoxy resin, silicone rubber, silicone compound having siloxane bond, and organic piezoelectric material (See Patent Documents 16 and 17)
(8) Transparent stress luminescent material (see Patent Document 18).

  It is important to apply the stress luminescent material to the fastener according to the light emission principle. In particular, it is preferable to apply a stress luminescent material that easily emits light by friction to the fastener. When applying a stress luminescent material to a bolt, a washer, a nut, or the like, it is preferable to apply the stress luminescent material to a surface to be pressed against a fixed object or a surface that rubs against the fixed object.

Examples of the stress luminescent material that easily emits light by friction include a metal complex and a ceramic-based stress luminescent material. In particular, a stress-stimulated luminescent material containing a sulfide, nitride, selenide, oxide, or telluride having a wurtzic structure or a spinel structure is suitable. Of these, a stress-stimulated luminescent material containing ZnS or ZnAl ₂ O ₄ as a base material is more preferable.

  In addition, if a stress light-emitting body is applied to the contact surface between the fastener and the object to be fixed, the friction coefficient of the fastener changes, so care must be taken in measuring the fixing force. That is, it is necessary to measure the coefficient of friction of the fastener with the stress-stimulated luminescent material applied and measure the fixing force based on the coefficient of friction.

  In addition, when a stress light emitter is applied to a portion that is deformed by a tensile force, such as a bolt that is an embodiment according to the present invention described above, the stress light emitter emits light sensitively to torque or tension. Is preferably used. As such a stress luminescent material, for example, a modified luminescent silicate or oxide, particularly a strontium aluminate-based stress luminescent material is effective.

[2. (Method for manufacturing fastener)
Next, a method for manufacturing the fastener according to the present invention will be described. In order to manufacture the fastener according to the present invention, the stress luminescent material particles used as the raw material of the stress luminescent material may be mixed with the raw material of the fastener, or the stress luminescent material may be provided on the surface of the fastener. You may apply | coat (coating).

  For example, if the former method is used, the elastic washer and the nut as the embodiment of the present invention can be produced by mixing the stress-stimulated luminescent particles with the resin or rubber and performing extrusion molding.

  In addition, the coating method has an advantage that can be applied to various materials such as metal. When using the coating method, it is necessary to uniformly disperse the stress-stimulated luminescent material and use a coating material having a strong adhesive force. In particular, coating using a urethane-based substrate is suitable.

[3. Configuration of fixing force measuring device]
One embodiment of the fixing force measuring apparatus of the present invention will be described below. As shown in FIG. 4, the fixing force measuring apparatus 10 of this embodiment includes an optical fiber 11 and an optical sensor (light intensity measuring means) 12. Further, the fixing jig 13 shown in FIG. 4 is for holding a measurement object when measuring the fixing force of the fastener, and is not necessarily a member necessary for the fixing force measuring device 10. Further, the washer type load cell 14 shown in FIG. 4 is also provided for verifying the measurement accuracy of the fixing force measuring apparatus 10 of the present embodiment, and is not an essential member for the fixing force measuring apparatus 10. .

  The optical fiber 11 guides light emitted from the stress light emitter 2 applied to the bolt 4, washer 1, or nut 3 as an embodiment of the fastener according to the present invention to the optical sensor 12.

  The optical sensor 12 measures the intensity of light guided by the optical fiber 11, and a photodiode or a photomultiplier tube can be used. In order to increase the measurement accuracy of the light intensity, a thermal filter or a band pass filter may be combined with the optical sensor.

  The present inventors conducted a fixing force measurement experiment using the fixing force measuring apparatus 10 having the above configuration, and the results will be described below. As shown in FIG. 4, the fixing force measurement experiment fixed the bolt 4 to the fixing jig 13, and washer 16, washer 1, washer type load cell 14, stainless steel plate 15, washer 1, and nut 3. The fixing was performed between the bolt 4 and the nut 17 in this order. Further, the fixing force measured by the washer-type load cell 14 and the light emission intensity from the washer 1 measured by the optical sensor 12 were compared by a recorder 18 with a memory.

  In addition, as washer 1, it experimented by replacing | exchanging suitably the thing of the structure shown to Fig.1 (a) thru | or FIG.1 (d). Similarly, the nut 3 is appropriately replaced with the one shown in FIGS. 2A to 2C, and the bolt 4 is one shown in FIG. 3A or 3B. Were replaced as appropriate.

  Further, as the bolt 4, a stainless steel bolt having a diameter of 10 mm and the stress-stimulated luminescent material 2 applied with a thickness of about 10 microns was used. Further, in order to detect light emission from the stress-stimulated luminescent material 2 applied to the bolt 4, a washer 16 having a notch 5 formed thereon was used. The optical fiber 11 was 3 mm in diameter.

Further, the stress-stimulated luminescent material 2 was formed from a high-intensity strontium-based stress luminescent material powder. That is, high-purity reagents SrCO ₃ , Al ₂ O ₃ , and Eu ₂ O ₃ were mixed to form Sr _0.97 Eu _0.01 Al ₂ O ₄ . Then, after calcining in the air at a temperature of 800 ° C., firing is performed in an atmosphere of Ar + 5% H _{2 in} a temperature range of 1000 to 1700 ° C., and Sr _0.97 Eu _0.01 in a meteor-type bol mill. Al ₂ O ₄ was pulverized. Further, the stress-stimulated phosphor powder was granulated to 5 microns or less by sieving. Finally, the granulated stress luminescent material fine particle powder was mixed with the urethane adhesive at a weight ratio of 1: 1 to form the stress luminescent material 2 as a paint. Note that the stress-stimulated luminescent material 2 was applied to the washer 1 and the nut 3 in the same procedure.

  In this way, the fixing force measuring device 10 and its peripheral members are arranged, and the stress in each of the washer 1, the nut 3 and the bolt 4 is changed while changing the fixing force by gradually tightening the nut 3 with a torque wrench. The relationship between the intensity of light emitted from the light emitter 2 and the tightening torque was examined. In addition, the measurement of the fixing force by the washer type load cell 14 was also performed at the same time. When the nut 17 was tightened with the same torque, the washer having the configuration shown in FIG. 1B showed the highest stress emission intensity.

  FIG. 5 and FIG. 6 show the relationship between the emission intensity measured by the photomultiplier tube as the optical sensor 12 and the fixing force measured by the washer type load cell 14. FIG. 5 shows the light intensity measured from the stress-stimulated luminescent material applied to the washer having the configuration shown in FIG. FIG. 6 shows the intensity of light measured from the stress-stimulated luminescent material applied to the entire washer as shown in FIG.

  5 and 6, it can be seen that the light emission intensity of the stress light emitter is proportional to the fixing force. Note that the washer having the configuration shown in FIG. 1 (d) showed higher light emission intensity than the washer having the stress luminescent material coated on the entire surface. Further, as shown in FIG. 6, it was found that the washer (see FIG. 1 (a)) having the stress-stimulated luminescent material applied to the entire surface increases the light emission intensity when the fixing force exceeds the threshold value. It was also examined that this threshold value depends on the type of stress luminescent material and the type of adhesive / paint binder.

  Also, as shown in FIG. 3B, when the stress illuminant was applied to the bolt, the light emission intensity of the stress illuminant increased as the fixing force measured by the washer type load cell increased. Furthermore, when the stress luminescent material was applied to the bolt as shown in FIG. 3A, the light emission intensity of the stress luminescent material increased when the fixing force measured by the washer type load cell exceeded the threshold value.

  Furthermore, it is possible to provide a fastener fastening device capable of measuring the fixing force easily and in real time by integrally configuring the fixing force measuring device of the present embodiment with a fastening means such as a nut runner or an impact wrench. Is possible.

[4. (Summary)
As described above, the fastener (washer 1, nut 3, bolt 4) of the present embodiment includes the stress light emitter 2, and further, according to the magnitude of mechanical strain to which the stress light emitter 2 is applied. Since the light emission intensity is indicated, the magnitude of the force generated in the fastener can be measured by measuring the light emission intensity from the stress light emitter 2.

  Here, the fastener is used for fixing an object by generating a force such as a tensile force or a frictional force therein. That is, it can be said that the magnitude of the force generated inside the fastener is the most accurate value for evaluating the fixing force for fixing the object. Therefore, by measuring the light emission intensity from the stress light emitter 2, the force with which the fastener fixes the object can be measured accurately.

  Moreover, since the stress illuminant 2 can be provided on the fastener by application regardless of the shape of the fastener, the force for fixing the object by various fasteners is easily measured. be able to. Moreover, since the stress light emitter 2 emits light instantaneously when an external force is applied, the fixing force by the fastener can be measured in real time.

  Further, the fixing force measuring device 10 of the present embodiment measures the force with which the object is fixed by a fastener, and the fastener emits light according to the magnitude of mechanical strain applied. And a light sensor 12 that measures the intensity of light emitted from the stress light emitter 2.

  According to the fixing force measuring device 10 having the above-described configuration, it is possible to accurately and in real time measure the force with which the fastener fixes the object without questioning what shape the fastener has. .

  In addition, according to the fastener fastening device including the fixing force measuring device 10 and the fastening means configured as described above, the fastener can be tightened while accurately managing the fixing force by the fastener in real time. Can be securely and securely fixed.

  INDUSTRIAL APPLICABILITY The present invention can be used in a very wide range of industries such as aerospace, transportation machinery, electrical / electronic equipment, machine / industry / general / precision machinery, civil engineering and construction, shipbuilding, and the like. In addition, since the fixing force of the fastener can be managed in real time, the present invention greatly contributes to quality maintenance and safety improvement of facilities / devices / equipment in which fastening parts are incorporated.

Fig.1 (a)-FIG.1 (d) are figures which show the structure of the washer based on one Embodiment of the fastener of this invention. Fig.2 (a)-FIG.2 (c) are figures which show the structure of the nut which concerns on one Embodiment of the fastener of this invention. Fig.3 (a)-FIG.3 (c) are figures which show the structure of the volt | bolt which concerns on one Embodiment of the fastener of this invention. It is a figure which shows the structure which concerns on one Embodiment of the fixing force measuring apparatus of this invention. It is a figure which shows the relationship between the emitted light intensity of the washer based on this invention, and fixing force. It is a figure which shows the relationship between the emitted light intensity of the washer based on this invention, and fixing force.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Washer 2 Stress light-emitting body 3 Nut 4 Bolt 10 Fixing force measuring device 12 Optical sensor (light intensity measuring means)

Claims (17)

  A fastener comprising a stress-stimulated illuminant that exhibits luminescence intensity in accordance with the magnitude of mechanical strain applied.   The fastener according to claim 1, wherein the fastener is a washer.   The fastener according to claim 2, wherein the stress-stimulated luminescent material is applied to the entire surface.   The fastener according to claim 2, wherein the stress-stimulated illuminant is formed so that a side surface of the washer extends in an axial direction of the washer, and connects both end surfaces of the washer.   The fastener according to claim 1, wherein the stress-stimulated luminescent material includes a sulfide, nitride, oxide, selenide, or telluride having a spinel structure.   The fastener according to claim 1, wherein the stress-stimulated luminescent material contains a wurtzite sulfide, nitride, oxide, selenide, or telluride.   The fastener according to claim 1, wherein the fastener is a nut.   The fastener according to claim 1, wherein the fastener is a bolt.   The fastener according to claim 8, wherein the stress-stimulated luminescent material is applied in a thin line extending in the axial direction.   The fastener according to claim 8, wherein the stress-stimulated luminescent material is applied in a thin line shape extending in the radial direction.   The fastener according to claim 1, wherein the stress luminescent material is a strontium aluminate-based stress luminescent material. A fixing force measuring device for measuring a force with which a target is fixed by a fastener,
The fastener is provided with a stress-stimulated illuminant that exhibits luminescence intensity in accordance with the magnitude of mechanical strain applied thereto,
A fixing force measuring apparatus comprising a light intensity measuring means for measuring the intensity of light emitted from the stress-stimulated luminescent material. A fixing force measuring device according to claim 12,
A fastener fastening apparatus comprising: a fastening means for fastening the fastener.   A method of manufacturing a fastener, comprising: applying a stress-stimulated luminescent material having a light emission intensity in accordance with a magnitude of mechanical strain applied to a surface of the fastener.   A method of manufacturing a fastener, comprising mixing a raw material of a stress-stimulated illuminant exhibiting a light emission intensity corresponding to the magnitude of mechanical strain applied and a raw material of the fastener.   A fixing method characterized by fixing an object using a fastener provided with a stress-stimulated illuminant showing light emission intensity corresponding to the magnitude of mechanical strain applied. A fixing force measuring method for measuring a force with which an object is fixed by a fastener,
The fastener is provided with a stress-stimulated illuminant that exhibits luminescence intensity in accordance with the magnitude of mechanical strain applied thereto,
A fixing force measuring method, wherein the intensity of light emitted from the stress-stimulated luminescent material is measured.

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