JP4318113B2 - Bolt gauge - Google Patents

Bolt gauge Download PDF

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Publication number
JP4318113B2
JP4318113B2 JP2003176065A JP2003176065A JP4318113B2 JP 4318113 B2 JP4318113 B2 JP 4318113B2 JP 2003176065 A JP2003176065 A JP 2003176065A JP 2003176065 A JP2003176065 A JP 2003176065A JP 4318113 B2 JP4318113 B2 JP 4318113B2
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JP
Japan
Prior art keywords
bolt
sensor
attached
gauge
head
Prior art date
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Expired - Fee Related
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JP2003176065A
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Japanese (ja)
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JP2005010064A (en
Inventor
敏雄 服部
行平 田中
Original Assignee
株式会社日立製作所
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Priority to JP2003176065A priority Critical patent/JP4318113B2/en
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Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a bolt gauge that measures strain and axial force acting on a bolt, and more particularly, to a bolt gauge using an optical fiber strain gauge.
[0002]
[Prior art]
Methods for measuring strain and axial force acting on the bolt include an ultrasonic probe method and a method using a strain gauge. In the ultrasonic probe method, a probe is installed on the head of the bolt, and the change in the axial length of the bolt is measured based on the reflection time of the ultrasonic wave from the bottom of the bolt, that is, the end face side of the shaft. And converted into axial force. This method requires careful handling because the processing accuracy of the bolt surface affects the measurement results, and the measuring device itself is relatively expensive. It is not suitable for the case where it is performed or when the axial force of a plurality of bolts is measured.
[0003]
On the other hand, the strain gauge is attached to the outer surface of the bolt shaft with an adhesive or the like, or the strain gauge sensor is mounted in a hole formed in the axial direction from the head to the shaft of the bolt. It is inserted and fixed with an adhesive or the like, and distortion is measured from a change in electrical resistance detected by a sensor unit (Patent Document 1). Patent Document 1 proposes a configuration in which an amplifier, a display unit, and the like are integrally formed and attached to a bolt in addition to a sensor unit, but in such an integrated configuration, there is a limit to the size of a bolt that can be used, Moreover, since one amplifier, a display part, etc. are needed for one sensor part, it is disadvantageous also in terms of cost.
[0004]
For this reason, as an electric resistance type strain gauge, generally, an amplifier, a display unit, and a sensor unit are configured separately and electrically connected by wiring or the like. However, such an electric resistance type strain gauge is advantageous in terms of cost because it can be used by replacing one amplifier or display unit with a plurality of sensor units, but every time an amplifier is electrically connected. Since balance adjustment is necessary, once the electrical connection between the amplifier and the sensor unit is disconnected, it is difficult to accurately measure a reduction in axial force due to loosening of the bolt. Furthermore, the electrical resistance type strain gauge has a problem that it is easily influenced by electromagnetic noise because it is necessary to measure a minute change in electrical resistance regardless of the configuration.
[0005]
Therefore, an optical fiber type strain gauge has been proposed as a strain gauge that is unnecessary or easy to adjust the balance and is not affected by electromagnetic noise (Patent Documents 2 and 3). In Patent Document 2, it is proposed to attach an optical fiber strain gauge to the surface of the ground anchor and measure the axial force applied to the ground anchor. It can also be applied to the measurement of axial force. And in patent document 3, a hole is formed from a head to a shaft in a bolt, a sensor part of an optical fiber type strain gauge is inserted into this hole, and an epoxy adhesive or the like is poured into this hole, Bolt gauges have been proposed in which a sensor part is bonded and fixed to a bolt. Further, these optical fiber type strain gauges are formed of an optical fiber in order to transmit an optical signal between a calculation unit and a sensor unit that calculate a strain value based on an optical signal from the sensor unit. Are connected to each other.
[0006]
[Patent Document 1]
Japanese Patent Application Laid-Open No. 11-118638 (page 2-3, FIG. 1)
[Patent Document 2]
JP 2002-81061 A (page 2-3, FIG. 1)
[Patent Document 3]
US Pat. No. 5,945,665 (column 2-3, FIG. 1)
[0007]
[Problems to be solved by the invention]
However, since the optical fiber is easy to break with the bolt attached using the optical fiber type strain gauge as described above, when handling the bolt, for example, when fastening the bolt, the light of the transmission unit is used. Great care must be taken not to break and break the fiber. For this reason, the bolt attached with the bolt gauge using the optical fiber type strain gauge has a problem that it is difficult to handle.
[0008]
An object of the present invention is to facilitate handling of a bolt to which a bolt gauge is attached.
[0009]
[Means for Solving the Problems]
The bolt gauge according to the present invention includes a sensor unit that is attached to a shaft portion of a bolt and generates an optical signal corresponding to the distortion of the bolt, an arithmetic unit that calculates strain based on the optical signal from the sensor unit, and a sensor unit Corresponds to the hole formed in the head of the bolt to which this sensor unit is mounted in a state where it protrudes from the surface of the head of the bolt to which the sensor unit is mounted and the transmission unit formed of an optical fiber that transmits the optical signal to the arithmetic unit The above-described problem is solved by providing a configuration including a protective tube that is attached to a position where the optical fiber forming the transmission portion is inserted.
[0010]
When handling a bolt with a bolt gauge attached, it is the boundary between the portion where the optical fiber is fixed to the bolt and the portion where the optical fiber is not fixed that the optical fiber of the transmission section is easily broken. Therefore, by adopting such a configuration, the portion of the optical fiber that becomes the boundary between the portion where the optical fiber is fixed to the bolt and the portion where the optical fiber is not fixed is covered and protected by the protective tube, and the transmission portion The optical fiber forming the is difficult to break. That is, the handling of the bolt with the bolt gauge attached can be facilitated.
[0011]
Furthermore, it is preferable that the protective tube is formed of a flexible tube because the optical fiber is more difficult to break.
[0012]
The protective tube is provided in a state where one end is in contact with the surface of the head of the bolt to which the sensor unit is attached, and the end of the protective tube in contact with the head of the bolt to which the sensor unit is attached. It is set as the structure provided with the fixing member which covers at least one part of a part and fixes a protective tube to the volt | bolt which attached the sensor part. With such a configuration, it is possible to attach a protective tube to a relatively small bolt, and even a relatively small bolt can easily handle a bolt to which a bolt gauge is attached.
[0013]
Here, when the sensor unit is fixed with an adhesive in a hole formed from the head of the bolt to the shaft, vacuuming is performed in order to remove bubbles formed in the adhesive. However, in the case of such a configuration having a protective tube and a fixing member that are in contact with the head surface of the bolt, if there is a space between the fixing member and the head surface of the bolt, a vacuum is drawn. In this case, the adhesive accumulates in this space. Thereby, the inside of the hole formed in the bolt may not be sufficiently filled with the adhesive, resulting in poor adhesion of the sensor unit, and the measurement accuracy of the bolt gauge may be reduced.
[0014]
On the other hand, a configuration in which a notch portion in which a tube wall is cut out from the surface side of the end portion is formed in an end portion that abuts the surface of the head of the bolt to which the sensor portion of the protective tube is attached. Then, when evacuation is performed, the adhesive does not accumulate in the space between the fixing member and the head surface of the bolt, and the hole formed in the bolt is sufficiently filled with the adhesive. A decrease in measurement accuracy of the bolt gauge can be suppressed.
[0015]
Further, if the sensor unit has a plurality of sensor units that are attached at different positions of the bolt, it is preferable because it can measure the strain acting on the bolt and the distribution of axial force, and can compensate the temperature of the measured strain and axial force. .
[0016]
Furthermore, it is attached to the head of the bolt to which the sensor unit is attached, and has a cover that forms a space between the head of the bolt and the protective tube is attached to the cover in a state of protruding from the cover. A correction sensor unit that generates an optical signal corresponding to the distortion of the cover is attached to the inner surface of the cover, and the arithmetic unit is connected to a bolt according to the optical signal from the correction sensor unit. The value calculated based on the optical signal from the sensor part attached to the shaft part is corrected. The value calculated from the optical signal from the correction sensor unit attached to the cover that is not easily affected by the distortion of the bolt indicates the thermal deformation of the cover, that is, the distortion due to the influence of the temperature. For this reason, a portion to which the axial force of the bolt is applied by correcting the value calculated from the optical signal from the sensor portion attached to the shaft portion of the bolt in accordance with the optical signal from the sensor portion for correction. It is possible to perform temperature compensation of the value detected by the sensor unit attached to the.
[0017]
Further, if the transmission unit has a connection member that optically connects the optical fibers and can be divided by this connection member, when handling the bolt, the transmission unit is divided by the connection member, and the bolt It is possible to make the optical fiber of the transmission part coming out of the cable as short as possible. For this reason, since the optical fiber forming the transmission part is more difficult to break, handling of the bolt attached with the bolt gauge can be further facilitated.
[0018]
Furthermore, the bolt gauge of the present invention includes a sensor unit that is attached to the shaft of the bolt and generates an optical signal corresponding to the distortion of the bolt, an arithmetic unit that calculates strain based on the optical signal from the sensor unit, and a sensor A transmission unit formed of an optical fiber that transmits an optical signal from the unit to the calculation unit, and a connection member that is provided in the transmission unit and optically connects the optical fibers, and the transmission unit is divided by the connection member The above-mentioned problem can be solved by adopting a configuration in which the connection member provided in the transmission part on the side continuous to the sensor part is attached to the head of the bolt to which the sensor part is attached. To do.
[0019]
A bolt gauge according to the present invention includes a sensor unit that is attached to a shaft portion of a bolt and generates an optical signal corresponding to the distortion of the bolt, an arithmetic unit that calculates strain based on the optical signal from the sensor unit, and a sensor A transmission unit formed of an optical fiber that transmits an optical signal from the unit to the calculation unit, and a first and a second provided at the ends of the optical fibers facing each other of the divided transmission unit. And a cover which is attached to the head of the bolt to which the sensor unit is attached and forms a space between the head of the bolt and the first lens is provided on the side connected to the sensor unit. Provided at the end of the transmission part, attached to the head of the bolt to which the sensor part is attached, and the second lens is provided at the end of the transmission part connected to the arithmetic unit And the cover is inside this cover Within formed space, to solve the above problems by adopting a configuration that supports the second lens in a state of being opposed to the first lens. At this time, the first lens and the second lens are both collimator lenses or Fresnel lenses.
[0020]
If it is set as such a structure, in the state which divided | segmented the transmission part by the connection member or the lens part, it will be in the state from which the optical fiber has not come out from the volt | bolt. For this reason, when the bolt is handled, the optical fiber forming the transmission part is hardly damaged, so that the bolt attached with the bolt gauge can be handled more easily.
[0021]
Furthermore, if it is set as the structure provided with the protective tube which is attached to the cover in the state protruded from the cover, and the optical fiber which forms a transmission part is penetrated, the divided | segmented transmission part is made into the 1st lens and the 2nd lens. Even after the optical connection, the optical fiber forming the transmission unit between the calculation unit and the bolt can be hardly damaged.
[0028]
DETAILED DESCRIPTION OF THE INVENTION
(First embodiment)
Hereinafter, a first embodiment of a bolt gauge to which the present invention is applied will be described with reference to FIGS. 1 and 2. FIG. 1 is a diagram showing a schematic configuration of a bolt gauge to which the present invention is applied, and is a sectional view of a bolt showing a state where a sensor portion is embedded in a hole formed in the bolt. FIG. 2 is a diagram showing a schematic configuration of a bolt gauge to which the present invention is applied, and is a side view of the bolt showing a state in which a sensor portion is attached to the surface of a shaft portion of the bolt.
[0029]
As shown in FIGS. 1 and 2, the bolt gauge 1 of the present embodiment is an optical fiber type strain gauge, and generates a light signal corresponding to the strain of the shaft portion of the bolt 3 to which the bolt gauge 1 is attached. 5, a transmission unit 7 formed of an optical fiber that transmits an optical signal from the sensor unit 5, and an external device 9 to which the end of the transmission unit 7 opposite to the sensor unit 5 is connected. ing. As the optical fiber type strain gauge, various types such as a fiber Bragg grating (hereinafter abbreviated as FBG) sensor can be used. Here, the case of an FBG sensor will be described as an example. The sensor unit 5 of the FBG sensor is formed by forming a plurality of slits or scratches on the optical fiber at predetermined intervals, and when the sensor unit 5 is distorted according to the distortion of the shaft portion of the bolt 3, the sensor unit 5 The plurality of slits or scratches formed in the space are installed so that the interval between them is changed.
[0030]
As a method of installing the sensor unit 5, there are a method of embedding the sensor unit 5 in the bolt 3 as shown in FIG. 1, a method of attaching the sensor unit 5 to the surface of the bolt 3 as shown in FIG. . In the method of embedding the sensor portion 5 in the bolt 3, as shown in FIG. 1, a hole 11 is formed in the bolt 3 from the top surface of the head portion 3a toward the end surface of the shaft portion 3b. Then, the sensor unit 5 is embedded in the hole 11 with an adhesive in a state where the sensor unit 5 is located at a position where the distortion of the shaft portion 3b, that is, a position where the axial force is received.
[0031]
At this time, the protective tube 13 into which the optical fiber to be the transmission unit 7 is inserted is installed in the opening of the hole 11 on the head 3 a side of the bolt 3. The protective tube 13 is partially inserted into the hole 11 formed in the bolt 3, and the remaining portion protrudes from the top surface of the head 3 a of the bolt 3. The portion inserted into the hole 11 is fixed to the hole 11 by using an adhesive or the like as necessary. The protective tube 13 is formed of a flexible tube, for example, a tube made of Teflon (registered trademark), another synthetic resin tube, or a metal flexible tube. As described above, the protective tube 13 is desirably a tube that has flexibility and bends when an appropriate force is applied in order to prevent breakage due to bending of the optical fiber.
[0032]
In the hole 11 formed in the bolt 3, an adhesive is put after the sensor portion 5 of the bolt gauge 1 and the like are inserted from the head 3 a side of the bolt 3. At this time, it is necessary to prevent a gap as much as possible between the inner surface of the hole 11 and the cured adhesive. A gap between the inner surface of the hole 11 and the cured adhesive is formed by bubbles or the like. For this reason, after putting an adhesive agent in the hole 11, a bubble removal is performed by evacuating. When evacuating, the end of the protective tube 13 on the side protruding from the bolt 3 in order to prevent the adhesive put in the hole 11 from coming out from the end opening on the side protruding from the bolt 3 of the protective tube 13 Block the opening with resin or adhesive.
[0033]
The hole 11 formed in the bolt can be formed as a through hole or has a bottom depending on the length and size of the bolt, the diameter of the hole 11, the viscosity of the adhesive used to fill the hole 11, and the like. It can also be formed as a bottomed hole. Moreover, for example, epoxy, cyanoacrylate, polyester, phenol, polyimide, polyurethane, synthetic rubber, or the like can be used as the adhesive that fills the hole 11 or the adhesive that closes the opening of the protective tube 13, and is cured at room temperature or heat. An amount of the adhesive that covers at least the sensor unit 5 is injected into the hole 11 so that at least the sensor unit 5 is buried in a completely cured adhesive as much as possible.
[0034]
On the other hand, in the method of attaching the sensor part 5 to the surface of the bolt 3, as shown in FIG. 2, the sensor part 5 is attached to an unthreaded part of the shaft part 3b of the bolt 3 using an adhesive or the like. Further, a protective sheet 15 is attached so as to cover the sensor unit 5. At a position corresponding to the position where the sensor portion 5 of the head portion 3a of the bolt 3 projecting is attached, a through hole 17 is formed between the surfaces of the head portion 3a of the bolt 3 projecting portion of the head 3a. Has been established. And the optical fiber which forms the transmission part 7 connected to the sensor part 5 is inserted in this through hole 17. At this time, the protective tube 13 into which the optical fiber forming the transmission unit 7 is inserted is installed in the opening portion of the through hole 17 located on the top surface side of the head 3 a of the bolt 3. A part of the protective tube 13 is inserted into a through hole 17 formed in the head 3 a of the bolt 3, and the remaining part protrudes from the top surface of the head 3 a of the bolt 3. The portion inserted into the through hole 17 of the protective tube 13 is fixed to the through hole 17 by using an adhesive or the like as necessary.
[0035]
In any configuration, the end of the transmission unit 7 connected to the sensor unit 5 on the side opposite to the side where the sensor unit 5 is provided is connected to the external device 9. The external device 9 that is a distortion amplifier responds to, for example, a light source of light transmitted to the sensor unit 5, a change in wavelength of an optical signal from the sensor unit 5, that is, a change in wavelength of light reflected by the sensor unit 5. It includes a calculation unit that calculates a distortion value, a recording unit that records the calculated value, and a display unit that displays the calculated value, that is, a measured value. A light source such as a laser light source can be installed not only in the external device 9 but also in the bolt 3. If the light source is installed in the bolt 3, the external device 9 can be downsized.
[0036]
When handling the bolt 3, for example, when fastening the bolt 3, the optical fiber forming the transmission unit 7 is easily broken and damaged because the optical fiber forming the transmission unit 7 is fixed to the bolt. And the portion where the optical fiber forming the transmission portion 7 comes out from the hole 11 or the through hole 17 formed in the bolt 3.
[0037]
On the other hand, in the bolt gauge 1 of the present embodiment, the optical fiber forming the transmission unit 7 is inserted through the protective tube 13 attached in a state of protruding from the top surface of the head 3 a of the bolt 3. ing. Therefore, for example, even when the transmission unit 7 is pulled when the bolt 3 is handled, the optical fiber serving as the transmission unit 7 is not easily bent by the protective tube 13, and the optical fiber is broken. It becomes difficult. Further, the protective tube 13 makes it difficult for a tool for fastening a bolt or the like to directly hit the optical fiber. As described above, the protective tube 13 makes it difficult for the optical fiber to be damaged, and therefore, it is possible to easily handle the bolt attached with the bolt gauge.
[0038]
Further, since the bolt gauge 1 uses an optical fiber type strain gauge, it is not affected by electromagnetic noise and can always measure the axial force generated in the bolt.
[0039]
(Second Embodiment)
A second embodiment of a bolt gauge to which the present invention is applied will be described below with reference to FIG. FIG. 3 is a diagram showing a schematic configuration of a bolt gauge to which the present invention is applied, and is a sectional view of the bolt showing a state where a sensor portion is embedded in a hole formed in the bolt. In the present embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof will be omitted. Configurations and features that are different from those in the first embodiment will be described.
[0040]
The difference between the bolt gauge of the present embodiment and the first embodiment is that a part of the protective tube is not inserted into the hole formed in the shaft portion from the head of the bolt. The protection tube is fixed to the head of the bolt by the fixing member in a state where it is in contact with the top surface of the head of the bolt. This is because the bolt gauge of this embodiment is smaller than the bolt to which the first embodiment is applied, such as M1 to M6, which cannot measure strain and axial force with an electrical resistance type strain gauge. Applicable to small diameter bolts. With such a small-diameter bolt, it is impossible to form a hole having such a diameter that the protective tube can be inserted.
[0041]
That is, in the bolt gauge 17 of the present embodiment, the protective tube 19 is installed in a state where one end surface of the protective tube 19 is in contact with the top surface of the head 3 a of the bolt 3. The protective tube 19 is a flexible tube formed of the same material as the protective tube of the first embodiment, and communicates with the opening of the hole 11 located on the top surface of the head 3 a of the bolt 3. is set up. The protective tube 19 is fixed by a fixing member 21 that is attached so as to cover an end portion of the protective tube 19 that is in contact with the top surface of the head portion 3a of the bolt 3 and a part of the side surface of the head portion 3a of the bolt 3. It is fixed to the head 3 a of the bolt 3. The fixing member 21 is a flexible resin having adhesiveness or adhesiveness, or a flexible tape in which an adhesive or an adhesive is applied on one side.
[0042]
Further, in the protective tube 19 of the present embodiment, a notch portion in which the tube wall of the protective tube 19 is cut out from the surface side of this end portion on the end portion of the bolt 3 that contacts the top surface of the head 3a. 25 is formed.
[0043]
After fixing the protective tube 19 to the head 3a of the bolt 3 with the fixing member 21, the sensor unit 5 injects an adhesive into the hole 11 and hardens it in the hole 11 as in the first embodiment. It is fixed in a state where it is buried in the adhesive. At this time, when an adhesive is injected into the hole 11 formed in the bolt 3 and evacuation is performed to remove bubbles, the fixing member 21, the top surface of the head 3 a of the bolt 3, the protective tube 19, etc. The adhesive enters and accumulates in the space 23 formed between the two. Thereby, the sensor part 5 may not be completely buried in the adhesive. However, in the present embodiment, since the cutout portion 25 is formed in the protective tube 19, the adhesive does not accumulate in the space 23 even if evacuation is performed, and the sensor portion 5 is hardened. Will be completely buried.
[0044]
Thus, in the bolt gauge 17 of the present embodiment, the protective tube 13 can be installed by the fixing member 21 even for a relatively small bolt that can only be formed with a hole having a diameter that the protective tube 13 cannot be inserted. For this reason, even a relatively small bolt can be easily handled when the bolt gauge is attached.
[0045]
By the way, as a method of installing a protection tube for a bolt of a size that can only form a hole that cannot be inserted into the protection tube, it is considered that the end surface of the protection tube and the end surface of the head of the bolt are attached by welding or bonding. However, in these methods, the protective tube may not be securely fixed to the head of the bolt, and the installation operation of the protective tube may be complicated. However, in the bolt gauge 17 of the present embodiment, the protective tube can be reliably fixed to a relatively small bolt by the fixing member 21, and the protective tube can be easily installed.
[0046]
Furthermore, in the bolt gauge 17 of the present embodiment, since the notch 25 is formed in the protective tube 19, the adhesive does not accumulate in the space 23 even if evacuation is performed, and the sensor unit 5 is cured. It can be securely embedded in the adhesive. If the sensor unit 5 is not completely buried in the adhesive, the distortion of the bolt 3 is transmitted only to a part of the sensor unit 5, so that the measurement accuracy of the bolt gauge is lowered. However, in the bolt gauge 17 of the present embodiment, the sensor unit 5 can be completely buried in the adhesive, and the distortion of the bolt 3 is transmitted to the entire sensor unit 5, thereby suppressing a decrease in measurement accuracy of the bolt gauge. can do.
[0047]
(Third embodiment)
Hereinafter, a third embodiment of a bolt gauge to which the present invention is applied will be described with reference to FIGS. FIG. 4 is a diagram showing a schematic configuration of a bolt gauge to which the present invention is applied, and is a sectional view of the bolt showing a state in which the first and second sensor portions are embedded in holes formed in the bolt. FIG. 5 is a diagram showing a schematic configuration of a bolt gauge to which the present invention is applied. The first sensor portion is embedded in a hole formed in the bolt, and the second sensor portion is attached to the surface of the shaft portion of the bolt. It is a side view of the bolt which shows a state. FIG. 6 is a diagram showing a schematic configuration of a bolt gauge to which the present invention is applied. The first sensor portion is embedded in a hole formed in the bolt, and the second sensor portion is attached to the surface of the shaft portion of the bolt. It is a side view of the bolt which shows a state. In the present embodiment, the same components and the like as those in the first and second embodiments are denoted by the same reference numerals and the description thereof is omitted, and the configurations and features that are different from those in the first and second embodiments are described. explain.
[0048]
The bolt gauge of this embodiment is different from the first and second embodiments in that it has a plurality of sensor parts of a first sensor part and a second sensor part to measure axial force distribution and measurement. It is to perform temperature compensation of the measured value. These first and second sensor units may be provided on one optical fiber or may be provided on separate optical fibers.
[0049]
First, the case where the 1st and 2nd sensor part is provided on one optical fiber is demonstrated. As shown in FIG. 4, the bolt gauge 27 uses an optical fiber for multipoint measurement. The optical fiber portion 29 connected to the transmission unit 7 has a plurality of sensor portions, that is, two sensor portions in this embodiment, that is, The first sensor unit 5 and the second sensor unit 31 are formed at predetermined intervals in order from the end side of the optical fiber portion 29 connected to the transmission unit 7. The portion 29 of the optical fiber in which the first sensor unit 5 and the second sensor unit 31 are formed is similar to the configuration of the first embodiment shown in FIG. 1 and the second embodiment of the bolt 3. It is inserted into a hole 11 formed from the top surface of the head portion 3a to the shaft portion 3b and embedded with an adhesive. Further, a protective tube 13 into which an optical fiber that is connected to the second sensor portion 31 and forms the transmission portion 7 is inserted is installed in the opening portion of the hole 11 on the top surface of the head 3a of the bolt 3. The protection tube 13 is partially inserted into the hole 11 formed in the head 3a of the bolt 3, and the remaining portion protrudes from the top surface of the head 3a of the bolt 3. The portion inserted into the hole 11 of the protective tube 13 is fixed to the hole 11 by using an adhesive or the like as necessary.
[0050]
As in the first and second embodiments, the first sensor unit 5 is attached to a portion to which the axial force of the bolt 3 is applied, that is, a portion in which the bolt 3 is distorted. On the other hand, the second sensor portion 31 is a portion where the axial force of the bolt 3 is applied, that is, a portion where the distortion of the bolt 3 occurs, and is attached to a position different from the first sensor portion 5 or the axial force of the bolt 3 is not applied. It is attached to the part, that is, the part where the bolt 3 is not distorted. When the second sensor unit 31 is positioned at a portion to which the axial force of the bolt 3 is applied, the axial force inside the bolt 3 is determined from the values measured by the first sensor unit 5 and the second sensor unit 31 attached at different positions. Can be measured.
[0051]
Moreover, when the 2nd sensor part 31 is located in the part to which the axial force of the volt | bolt 3 is not applied, the value measured by the 2nd sensor part 31 becomes distortion by the thermal deformation of the volt | bolt 3 produced with temperature. For this reason, the value calculated based on the optical signal from the first sensor unit 5 is corrected according to the value calculated based on the optical signal from the second sensor unit 31 to be measured by the first sensor unit 5. It is possible to perform temperature compensation of the measured value. The FBG sensor exemplified in the present embodiment can measure the temperature from the state of thermal deformation if the relationship between the temperature of the bolt and the characteristic of strain due to thermal deformation is known. The number of sensor units can be increased to the performance limit of the amplifier of the external device 9.
[0052]
Next, a case where the first and second sensor units are provided on separate optical fibers will be described. In the bolt gauge 33, as shown in FIG. 5, a plurality of optical fibers in which one sensor unit is formed, in this embodiment, an optical fiber 35 in which the first sensor unit 5 is formed, and a second sensor unit 31. Two optical fibers with the formed optical fiber 37 are used, and each optical fiber 35, 37 has an end portion on the opposite side to the end portion on which the first and second sensor portions 5, 31 are formed. To the optical switch 39. The optical switch 39 is connected to the external device 9 via the transmission unit 7.
[0053]
The first sensor portion 5 is inserted into the hole 11 formed from the top surface of the head 3a of the bolt 3 to the shaft portion 3b in the same manner as the configuration shown in FIG. 1 and the second embodiment in the first embodiment. And embedded with adhesive. Similar to the configuration shown in FIG. 2 in the first embodiment, the second sensor unit 31 is attached using, for example, an adhesive to an unthreaded portion of the shaft 3b of the bolt 3, The protective sheet 15 is covered. At a position corresponding to the position where the second sensor portion 31 of the portion of the head 3 a of the bolt 3 that protrudes in the hook shape is attached, the through hole 17 extends between the surfaces of the portion of the head 3 a that protrudes like the hook of the bolt 3. Is drilled. The optical fiber 37 connected to the second sensor unit 31 is inserted into the through hole 17.
[0054]
Here, in the opening of the hole 11 on the top surface side of the head 3 a of the bolt 3, a protective tube 13 into which the optical fiber 35 in which the first sensor portion 5 is formed is inserted is installed. In the opening of the through hole 17 located on the top surface side of the portion 3a, the protective tube 13 into which the optical fiber 37 in which the second sensor portion 31 is formed is inserted is installed. Each protection tube 13 is partially inserted into the holes 11 and 17 formed in the bolt 3, and the remaining portions protrude from the top surface of the head 3a of the bolt 3, The portions inserted into the holes 11 and 17 of the protective tube 13 are fixed to the holes 11 and 17 by using an adhesive as necessary.
[0055]
Note that the number of optical fibers installed in the bolt 3, that is, the number of sensor units, can be increased to the limit of the channel of the optical switch 39. In the configuration shown in FIG. 5, the second sensor portion 31 and the first sensor portion 5 are arranged on the surface of the shaft portion 3 b of the bolt 3 and the central portion in the shaft portion 3 b, respectively. Thus, when the bolt 3 is bent, both the axial force and the bending of the bolt 3 can be measured based on the information from the first and second sensor parts 5 and 31. Further, similarly to the above-described configuration, the distortion value due to thermal deformation can be corrected.
[0056]
When the first and second sensor units are provided on separate optical fibers, as shown in FIG. 9, the optical fiber that becomes the transmission unit 7 via the coupler 41 is divided into two optical fibers 35, A bolt gauge 43 having a structure branched to 37 may be used.
[0057]
In such a bolt gauge 27, 33, 43 of this embodiment as well, the optical fiber is not easily broken and broken as in the first and second embodiments, so that the bolt with the bolt gauge attached can be easily handled. Can be. Furthermore, since the bolt gauges 27, 33, and 43 of the present embodiment have a plurality of sensor portions 5 and 31, measurement of the distribution and bending of the axial force of the bolt, correction of distortion values due to thermal deformation, and the like. Can do.
[0058]
(Fourth embodiment)
Hereinafter, a fourth embodiment of a bolt gauge to which the present invention is applied will be described with reference to FIG. FIG. 7 is a view showing a schematic configuration of a bolt gauge to which the present invention is applied in an enlarged state of a head portion of the bolt, and shows a state in which a sensor portion is embedded in a hole formed in the bolt and a portion of the bolt and the cover. FIG. In the present embodiment, the same components as those in the first to third embodiments are denoted by the same reference numerals and the description thereof is omitted, and the configurations and features that are different from those in the first to third embodiments are described. explain.
[0059]
As in the third embodiment, the bolt gauge of the present embodiment has two sensor units, a first sensor unit and a second sensor unit, and measures axial force distribution and temperature compensation of the measured values. However, the third embodiment is different from the third embodiment in that a cylindrical cover whose one end is closed is installed on the top surface of the bolt head, and the second sensor portion is provided on the inner surface of the cover. That is, the bolt gauge 45 of this embodiment is the same as the configuration shown in FIG. 5 in the third embodiment as shown in FIG. 7, and the transmission unit 7 is connected to the optical switch 39 via the optical switch 39 in FIG. It is branched into two optical fibers, an optical fiber 35 in which a first sensor portion (not shown) is formed and an optical fiber 37 in which a second sensor portion 31 is formed.
[0060]
A cylindrical cover 47 whose one end is closed is attached to the top surface of the head 3 a of the bolt 3. The cover 47 of the present embodiment shows a case where the ring-shaped end face on the opening side of the cylindrical cover 47 is fixed to the top face of the head 3 a of the bolt 3 with an adhesive. However, the cover 47 is not only fixed to the top surface of the head 3a of the bolt 3 with an adhesive, but also, for example, the end of the cover 47 on the open side and the top surface side of the head 3a of the bolt 3 are mutually connected. A method of cutting and screwing the corresponding screw, or forming a groove corresponding to the ring-shaped end of the cover 47 on the top surface of the head 3a of the bolt 3, and opening the cover 47 in this groove. It can be attached by various methods such as a method of fitting the ring-shaped end portion on the side. Note that the cover 47 is formed of the same material as that of the bolt 3 or a material whose strain characteristics with respect to temperature are known.
[0061]
Such a closed end wall of the cover 47 has two positions: a position corresponding to the hole 11 formed from the top surface of the head 3 a of the bolt 3 to the shaft portion 3 b and a position near the side wall of the cover 47. The protective tube 13 is fixed in a state where it passes through the wall of the closed end of the cover 47 and protrudes outward from the wall of the closed end of the cover 47. An optical fiber 35 having a first sensor portion (not shown in FIG. 7) is inserted through the protective tube 13 at a position corresponding to the hole 11 formed in the bolt 3. The optical fiber 35 is inserted into the hole 11 formed in the bolt 3, and the first sensor portion (not shown in FIG. 7) is embedded in the hole 11 formed in the bolt 3 with an adhesive. An optical fiber 37 in which the second sensor portion 31 is formed is inserted through the protective tube 13 at a position near the side wall surface of the cover 47. The second sensor unit 31 is attached to the inner surface of the side wall of the cover 47 using an adhesive or the like, and is further covered with the protective sheet 15.
[0062]
By installing the second sensor unit 31 in the cover 47 that is hardly affected by the distortion of the bolt as described above, the distortion due to the thermal deformation of the bolt 3 can be corrected more accurately than in the third embodiment, and the temperature compensation can be further improved. It can be done reliably. In the case of this embodiment, the present invention can be applied when the temperature difference between the threaded portion of the bolt 3, that is, the shaft portion 3 b and the cover 47 is relatively small, that is, when the temperature of the working atmosphere of the bolt 3 is uniform.
[0063]
Even in the bolt gauge 45 of this embodiment, by providing the protective tube 13 on the cover 47, the optical fiber is not easily broken, as in the first to third embodiments, and the bolt gauge attached with the bolt gauge is made. Easy handling. Furthermore, when the temperature of the working atmosphere of the bolt 3 is uniform, temperature compensation can be performed more reliably.
[0064]
(Fifth embodiment)
A fifth embodiment of a bolt gauge to which the present invention is applied will be described below with reference to FIG. FIG. 8 is a diagram showing a schematic configuration of a bolt gauge to which the present invention is applied, and is a sectional view of the bolt showing a state where a sensor portion is embedded in a hole formed in the bolt. In the present embodiment, the same components as those in the first to fourth embodiments are denoted by the same reference numerals and description thereof is omitted, and the configurations and features that are different from those in the first to fourth embodiments are described. explain.
[0065]
The difference between the bolt gauge of the present embodiment and the first to fourth embodiments is that a connection member that can be attached to and detached from the transmission part that comes out of the bolt is provided, and the transmission part can be divided by this connection member. There is. That is, as shown in FIG. 8, the bolt gauge 49 of the present embodiment is the same as the configuration shown in FIG. 1 in the first embodiment, and the bolt 3 extends from the top surface of the head 3a to the end surface of the shaft portion 3b. The hole 11 is bored toward the sensor 11, and the sensor unit 5 is embedded in the hole 11 in a state where the sensor unit 5 is positioned at a position where the shaft 3 b is distorted, that is, a position that receives the axial force. At this time, the protective tube 13 into which the optical fiber to be the transmission unit 7 is inserted is installed in the opening of the hole 11 on the top surface side of the head 3 a of the bolt 3. The protective tube 13 is partially inserted into the hole 11 formed in the bolt 3, and the remaining portion protrudes from the top surface of the head 3 a of the bolt 3. The portion inserted into the hole 11 is fixed to the hole 11 by using an adhesive or the like as necessary.
[0066]
However, in the bolt gauge 49 of the present embodiment, the transmission unit 7 includes an optical fiber that forms the transmission unit 7 a on the side connected to the external device 9 and an optical fiber that forms the transmission unit 7 b that is connected to the sensor unit 5. The optical fiber is divided into two optical fibers. An end of the optical fiber forming the transmission unit 7a opposite to the side connected to the external device 9, and an end of the optical fiber forming the transmission unit 7b opposite to the side where the sensor unit 5 is formed Are provided with connectors 51a and 51b which are connection members for optical connection of optical fibers.
[0067]
For the connectors 51a and 51b, FC connectors for optical fibers, SC connectors, and the like are used. When handling the bolt 3, such as when fastening the bolt 3, the connector 51a, 51b is removed. In order to surely prevent the optical fiber from being damaged when the bolt 3 is handled, the length of the portion protruding from the top surface of the head 3a of the bolt 3 of the optical fiber to be the transmission portion 7b is 5 cm or less. It is desirable to do.
[0068]
In such a bolt gauge 49 of this embodiment, the protective tube 13 protruding from the opening of the hole 11 on the top surface side of the head 3a of the bolt 3 is provided, and the transmission unit 7 is connected by the connectors 51a and 51b. The transmission part 7a and the transmission part 7b can be separated. For this reason, in addition to making it difficult for the optical fiber to be damaged by the protective tube 13, the bolt 3 can be handled in a state where the bolt 3 is separated from the external device 9. Therefore, since the optical fiber is less likely to be broken, the bolt with the bolt gauge attached can be handled more easily.
[0069]
In addition, the external device 9 can be removed except when necessary, and the optical fiber strain gauge does not require or is easy to adjust the balance. Is possible.
[0070]
(Sixth embodiment)
Hereinafter, a sixth embodiment of a bolt gauge to which the present invention is applied will be described with reference to FIGS. 9 and 10. FIG. 9 is a diagram showing a schematic configuration of a bolt gauge to which the present invention is applied, and is a cross-sectional view of a bolt showing a configuration using a connector as a connecting member provided in the transmission section. FIG. 10 is a diagram showing a schematic configuration of a bolt gauge to which the present invention is applied, and is a cross-sectional view of a bolt showing a configuration using a ferrule or a sleeve as a connection member provided in the transmission section. In the present embodiment, the same components as those in the first to fifth embodiments are denoted by the same reference numerals and description thereof is omitted, and the configurations and features that are different from those in the first to fifth embodiments are described. explain.
[0071]
As in the fifth embodiment, the bolt gauge according to the present embodiment divides the transmission part via a detachable connecting member, but without using a protective tube, the part of the transmission part that is continuous with the sensor part. The point from which the connection member provided in the edge part was attached to the head top surface of the volt | bolt differs from 5th Embodiment. That is, as shown in FIG. 9, the bolt gauge 53 of the present embodiment is similar to the configuration of the fifth embodiment, and the light that forms the transmission unit 7a on the side where the transmission unit 7 is connected to the external device 9 is used. It is in a state of being divided into two optical fibers, that is, the fiber and an optical fiber that forms the transmission unit 7 b connected to the sensor unit 5. An end of the optical fiber forming the transmission unit 7a opposite to the side connected to the external device 9, and an end of the optical fiber forming the transmission unit 7b opposite to the side where the sensor unit 5 is formed Are provided with connectors 51a and 51b, which are connection members for optical connection.
[0072]
In this embodiment, the hole 3 is drilled in the bolt 3 from the top surface of the head 3a toward the end surface of the shaft portion 3b, but the opening of the hole 3 in the top of the head 3a of the bolt 3 is The connector 51b provided in the transmission part 7b is formed in a shape that can be fitted. And the transmission part 7b is inserted in the hole 11 formed in the volt | bolt 3 with the sensor part 5 as a whole, and the connector 51b provided in the transmission part 7b is in the head 3a top surface of the volt | bolt 3 of the hole 11. It is attached to the opening by using an adhesive or the like as appropriate. The sensor unit 5 is embedded in the hole 11 with an adhesive as in the other embodiments.
[0073]
Note that the connecting member may be formed of a ferrule, a sleeve, or the like instead of the connectors 51a and 51b. In the bolt gauge 55 provided with such a connection member, as shown in FIG. 10, a ferrule 57a and a connector covering the ferrule 57a are formed at the end of the optical fiber forming the transmission unit 7a on the side connected to the external device 9. 59, and a ferrule 57b is attached to the end of the optical fiber forming the transmission part 7b connected to the sensor part 5. Therefore, the opening of the hole 3 at the top surface of the head 3a of the bolt 3 is formed in a shape that can fit the ferrule 57b provided in the transmission portion 7b, and the ferrule 57b is attached. In the case of such a connection member, a ferrule 57 a provided in the transmission unit 7 a connected to the external device 9 and a ferrule 57 b provided in the transmission unit 7 b connected to the sensor unit 5 are connected using a sleeve 61.
[0074]
When the connector 51b is embedded in the opening at the top surface of the head 3a of the bolt 3 in the hole 11, the diameter of the opening becomes relatively large. However, in the configuration in which the ferrule 57b is embedded, the opening of the hole 11 can be made small, and the machining operation of the hole 11 can be simplified, and the present embodiment can be applied to a relatively small bolt.
[0075]
In these bolt gauges 53, 55, when handling the bolt 3, such as when fastening the bolt 3, the connectors 51a, 51b or the ferrules 57a, 57b and the sleeve 61 are removed, and the transmission parts 7a, 7b Is performed in a state of being divided. At this time, no optical fiber comes out from the bolt 3.
[0076]
In the bolt gauges 53 and 55 according to this embodiment, the bolt 3 can be handled in a state where the bolt 3 is separated from the external device 9 and the optical fiber is not out of the bolt 3. Therefore, when the bolt is handled, the optical fiber is hardly damaged, and the bolt with the bolt gauge attached can be handled more easily.
[0077]
(Seventh embodiment)
Hereinafter, a seventh embodiment of a bolt gauge to which the present invention is applied will be described with reference to FIGS. 11 and 12. FIG. 11 is a diagram showing a schematic configuration of a bolt gauge to which the present invention is applied in an enlarged state of the head portion of the bolt. The configuration for optical connection using a collimator lens is shown in the bolt and cover portion. It is a figure shown in a cross section. FIG. 12 is a diagram showing a schematic configuration of a bolt gauge to which the present invention is applied in an enlarged state of the head portion of the bolt. The configuration for optical connection using a Fresnel lens is shown in the bolt and cover portion. It is a figure shown in a cross section. In the present embodiment, the same components as those in the first to sixth embodiments are denoted by the same reference numerals and description thereof is omitted, and the configurations and features that are different from those in the first to sixth embodiments. explain.
[0078]
The bolt gauge of this embodiment has divided the transmission part as in the fifth and sixth embodiments. However, a connector or a ferrule is used for optical connection of two optical fibers that become the divided transmission parts. A difference from the fifth and sixth embodiments is that a lens is used without being used and optical connection is performed by a non-contact transmission method. That is, as shown in FIG. 11, the bolt gauge 63 of this embodiment is the same as the configuration of the fifth and sixth embodiments, and the transmission unit 7 has a transmission unit 7a on the side connected to the external device 9. The optical fiber to be formed and the optical fiber forming the transmission unit 7b connected to the sensor unit (not shown in FIG. 11) are divided into two optical fibers. However, in this embodiment, the end of the transmission unit 7a opposite to the side connected to the external device 9 and the end of the transmission unit 7b opposite to the side where the sensor unit (not shown in FIG. 11) is formed. Collimator lenses 65a and 65b are provided in the sections.
[0079]
The collimator lens 65b provided in the transmission unit 7b is appropriately formed in an opening at the top surface of the head 3a of the bolt 3 in the hole 11 formed from the top surface of the head 3a of the bolt 3 toward the end surface of the shaft portion 3b. It is attached by using an adhesive or the like. The transmission part 7b is inserted into a hole 11 formed in the bolt 3 as a whole together with a sensor part not shown in FIG. The sensor unit 5 is embedded in the hole 11 with an adhesive as in the other embodiments.
[0080]
On the other hand, the collimator lens 65 a provided in the transmission unit 7 a is fixed to a cover 67 attached to the top surface of the head 3 a of the bolt 3. The cover 67 is a cylindrical member whose one end is closed. In the present embodiment, the ring-shaped end surface on the open side of the cylindrical cover 67 is fixed to the top surface of the head 3a of the bolt 3 with an adhesive. Shows the case. However, the cover 67 is not only fixed to the top surface of the head portion 3a of the bolt 3 with an adhesive, but also corresponds to, for example, the end portion of the cover 67 on the open side and the top surface side of the head portion 3a of the bolt 3. A groove corresponding to the ring-shaped end of the cover 67 on the opening side of the cover 67 is formed on the top surface of the head 3a of the bolt 3, and the groove on the opening side of the cover 67 is formed in this groove. It can be attached by various methods such as a method of fitting ring-shaped ends.
[0081]
The cover 67 is attached to the wall of the closed end of the cover 67 in a state where the protective tube 13 protrudes outside the cover at a position corresponding to the collimator lens 65b fixed to the top surface of the head 3a of the bolt 3. It has been. The collimator lens 65a is attached to the end portion of the protective tube 13 located in the cover 67 by using an adhesive or the like as appropriate. Therefore, by attaching the cover 67 to the top surface of the head 3a of the bolt 3, the collimator lens 65a faces the collimator lens 65b and is placed on the cover 67 with a predetermined distance from the collimator lens 65b. Supported. In order to reliably obtain the necessary transmission accuracy of the optical signal, the accuracy of the angle difference between the surface of the collimator lens 65a and the surface of the collimator lens 65b is about 0.2 degrees or less, and the eccentric axis deviation distance is 200 μm or less. It is desirable to arrange with.
[0082]
As a configuration for performing optical connection by the non-contact transmission method, not only a configuration using a collimator lens but also an end opposite to the side connected to the external device 9 of the transmission unit 7a as shown in FIG. And a bolt gauge 71 provided with Fresnel lenses 69a and 69b on the opposite side of the transmission part 7b and the side where the sensor part (not shown in FIG. 11) is formed. You can also. The configuration of the bolt gauge 71 using the Fresnel lenses 69a and 69b is the same as that using the collimator lens except that a Fresnel lens is used instead of the collimator lens.
[0083]
In these bolt gauges 63 and 71, when the bolt 3 is handled, for example, when the bolt 3 is fastened, the cover 67 is not attached to the head 3a of the bolt 3. Therefore, when the bolt 3 is handled, no optical fiber comes out of the bolt 3.
[0084]
In such bolt gauges 63 and 71 of the present embodiment, the bolt 3 can be handled in a state where no optical fiber comes out from the bolt 3 and the bolt 3 is separated from the external device 9. Therefore, when the bolt is handled, the optical fiber is hardly damaged, and the bolt with the bolt gauge attached can be handled more easily.
[0085]
Further, since the protective tube 13 is provided on the cover 67, the optical fiber can be hardly damaged even after the cover 67 is attached to the head 3a of the bolt 3.
[0086]
Note that it is desirable that the cover 67 be detachably attached to the top surface of the head 3a of the bolt 3 because one external device can be used for a plurality of bolts. Therefore, even when fixing using an adhesive, it is desirable to use a type of adhesive that can release the adhesive state as easily as possible.
[0087]
( Reference example )
Hereinafter, a bolt gauge to which the present invention is applied will be described. Reference example Will be described with reference to FIGS. FIG. 13 is a perspective view showing a schematic configuration of a bolt gauge to which the present invention is applied. FIG. 14 is a perspective view showing the form of a columnar member of a bolt gauge to which the present invention is applied and how to attach the sensor unit to the columnar member. FIG. 14A is a perspective view of forming the sensor unit by forming a hole in the columnar member. The form to embed, (b) is a figure which divides | segments a columnar member into two, sandwiches a sensor part, and (c) is a figure which shows the form which affixed the sensor part on the surface of the columnar member. FIG. 15 is a diagram showing a schematic configuration of a bolt gauge to which the present invention is applied, and is a perspective view showing a configuration provided with a protective tube. Book Reference example In the following description, the same components as those in the first to seventh embodiments are denoted by the same reference numerals.
[0088]
Book Reference example As shown in FIG. 13, the bolt gauge 73 is an optical fiber strain gauge. The sensor section 5 generates an optical signal corresponding to the distortion of the shaft portion of the bolt 3 to which the bolt gauge 73 is attached, and the sensor section 5. A transmission unit 7 formed of an optical fiber that transmits an optical signal from the sensor, an external device 9 to which the end of the transmission unit 7 opposite to the sensor unit 5 is connected, and the sensor unit 5 and the sensor unit 5 It consists of a columnar member 75 to which a part of the optical fiber forming the transmission unit 7 is attached.
[0089]
A bolt 77 to which the bolt gauge 73 is attached is provided with a hole 77 through which the entire columnar member 75 can be inserted from the top surface of the head 3a toward the end surface of the shaft portion 3b. Then, the columnar member 75 to which the sensor unit 5 and a part of the transmission unit 7 connected to the sensor unit 5 are attached is inserted into the hole 77 from the end on the side where the transmission unit 7 does not come out, and is fixed with an adhesive. . Thus, in the present embodiment, the bolt gauge 73 is attached to the bolt 3 by fixing the columnar member 75 to the hole 77. At this time, the sensor unit 5 attached to the columnar member 75 is brought to a position where distortion of the shaft portion 3b of the bolt 3 occurs, that is, a position where the axial force is received.
[0090]
The columnar member 75 has a columnar shape, and the end of the columnar member 75 on the side to be inserted into the hole 77 formed in the bolt 3 has a flat surface, a hemispherical surface, and a conical surface, and the other end, that is, the transmission unit 7. The end on the side from which the optical fiber forming the surface protrudes has a flat surface. In addition, the columnar member 75 can be formed of various materials such as metal, resin, glass, and ceramic. When the columnar member 75 is formed of a sponge-like elastic body, an adhesive is used for fixing to the bolt 3. Is used more than with other materials and cured with an adhesive.
[0091]
The hole 77 formed in the bolt can be formed as a through hole depending on the length and size of the bolt, the diameter of the hole 77, the viscosity of the adhesive used to fill the hole 77, and the like. It can also be formed as a bottomed hole having a bottom on the shaft portion 3b side. As an adhesive for fixing the columnar member 75 to the hole 77, for example, epoxy, cyanoacrylate, polyester, phenol, polyimide, polyurethane, synthetic rubber, or the like is used, and is cured at room temperature or heat.
[0092]
By the way, the reliability of adhesion of the sensor part to the bolt affects the measurement accuracy of the axial force of the bolt. When the sensor unit alone is inserted into the hole formed in the bolt and embedded with an adhesive, if the diameter of the hole formed in the bolt is larger than the size of the sensor unit, the sensor unit and the inner surface of the hole formed in the bolt The interval between the two becomes large, and the amount of adhesive used increases. When the amount of the adhesive is increased in this way, bubbles and the like are liable to enter the adhesive, so that poor adhesion is likely to occur and the reliability of the adhesion is lowered. In particular, in an optical fiber type strain gauge, since the size of the sensor part is relatively small, the distance between the sensor part and the inner surface of the hole formed in the bolt is limited due to processing restrictions on the diameter of the hole that can be formed in the bolt. Becomes relatively large. Therefore, in a bolt gauge using an optical fiber type strain gauge, when the sensor part is embedded in a hole formed in the bolt, adhesion failure is likely to occur, and there may be a problem in the measurement accuracy of the bolt gauge. In addition, in order to improve the bonding reliability of the sensor unit, skill in bonding work is required.
[0093]
Book against this Reference example In the bolt gauge 73, when fixing the columnar member 75 to the hole 77 formed in the bolt 3 with an adhesive, the adhesive is applied to the outer surface of the columnar member 75 and inserted into the hole 77 formed in the bolt 3. Thus, an adhesive can be filled between the inner surface of the hole 77 formed in the bolt 3 and the outer surface of the columnar member 75. Further, since the diameter of the hole 77 formed in the bolt 3 and the outer diameter of the columnar member 75 are larger than the diameter of the optical fiber, the diameter of the hole 77 formed in the bolt 3 and the outer diameter of the columnar member 75 are reduced. The machining accuracy of the diameter can be improved, and the gap between the inner surface of the hole 77 formed in the bolt 3 and the outer surface of the columnar member 75 can be controlled. Thereby, the quantity of the adhesive agent for filling between the inner surface of the hole 77 formed in the volt | bolt 3 and the outer surface of the columnar member 75 can be reduced, and mixing of a bubble etc. can be suppressed. Therefore, the adhesion reliability can be improved, and the measurement accuracy of the bolt gauge can be improved.
[0094]
Further, when the columnar member 75 is fixed to the hole 77 formed in the bolt 3 with an adhesive, the adhesive is simply applied to the outer surface of the columnar member 75 and inserted into the hole 77 formed in the bolt 3. Since the reliability is improved and the sensor unit 5 can be firmly fixed inside the bolt, no skill is required for the bonding operation.
[0095]
Further, the form of the columnar member and the mounting form of the sensor unit and the like are not limited to the form of attaching the sensor unit 5 and a part of the transmission unit 7 connected to the sensor unit 5 to the surface of the columnar member 75 as shown in FIG. Can be in various forms. For example, as shown in FIG. 14A, a columnar member 81 in which a hole 79 is formed along the central axis is used, and the sensor unit 5 may be embedded with an adhesive in the hole 79 formed in the columnar member 81. it can. Further, as shown in FIG. 14B, the sensor unit 5 is sandwiched between the split surfaces of the divided columnar member pieces 83 a and 83 b that form the columnar member 83 using a columnar member 83 that is divided into two in the extending direction. It is also possible to bond the divided surfaces of the columnar member pieces 83a and 83b with an adhesive.
[0096]
In addition, as shown in FIG. 14 (c), a columnar member 85 to which an optical fiber to be the transmission unit 7 is attached so as to be folded back at the end portion to be inserted into the hole 77 formed in the bolt 3 may be used. it can. In this case, the optical fiber which becomes the two transmission parts 7 has come out from the edge part of the columnar member 85. FIG. Therefore, even if the optical fiber serving as one transmission unit 7 is broken and disconnected, measurement can be performed by connecting the optical fiber serving as the other transmission unit 7 to the external device 9. Although not shown, if the optical fiber is spirally wound around the circumferential surface of the columnar member, the bending curvature of the sensor unit 5 can be increased, and light loss can be reduced.
[0097]
Also book Reference example In the bolt 3 to which a bolt gauge using an optical fiber type strain gauge such as the bolt gauge 73 is attached, since the optical fiber is easily broken, when the bolt 3 is handled, for example, when the bolt 3 is fastened, It is necessary to pay close attention so as not to break and break the optical fiber portion serving as the transmission unit 7. For this reason, in the bolt 3 to which the bolt gauge 73 is attached as in the present embodiment, there is a case in which the handling of the bolt 3 becomes difficult. The portion where the optical fiber is easily broken and broken is the boundary portion between the portion fixed to the bolt 3 of the optical fiber forming the transmission portion 7 and the portion not fixed, that is, the optical fiber forming the transmission portion 7 from the bolt 3. Are portions that come out of the columnar members 75, 81, 83, 85 and the like.
[0098]
When such a problem occurs, for example, when a columnar member 81 in which a hole 79 is formed along the central axis is used, as shown in FIG. 15, in the opening of the hole 79 formed in the columnar member 81, A configuration such as a bolt gauge 87 in which a protective tube 13 into which an optical fiber forming the transmission unit 7 is inserted is provided. The protective tube 13 is partially inserted into a hole 79 formed in the columnar member 81, and the remaining portion protrudes from the end surface of the columnar member 81. The portion inserted into the hole 79 is fixed to the hole 79 by using an adhesive or the like as necessary.
[0099]
In the bolt gauge 87 having such a configuration, the optical fiber serving as the transmission unit 7 is inserted into the protective tube 13 protruding from the end surface of the columnar member. Accordingly, since the optical fiber is not easily broken, it is possible to easily handle the bolt attached with the bolt gauge. That is, the measurement accuracy of the bolt gauge can be improved, and handling of the bolt with the bolt gauge attached can be facilitated.
[0100]
1st to 1st 7 Embodiment of And reference examples These configurations can be used in combination as appropriate.
[0101]
【The invention's effect】
According to the present invention, it is possible to easily handle a bolt to which a bolt gauge is attached.
[Brief description of the drawings]
FIG. 1 is a diagram showing a schematic configuration of a first embodiment of a bolt gauge to which the present invention is applied, and is a sectional view of a bolt showing a state in which a sensor portion is embedded in a hole formed in the bolt.
FIG. 2 is a diagram showing a schematic configuration of a first embodiment of a bolt gauge to which the present invention is applied, and is a side view of the bolt showing a state in which a sensor portion is attached to the shaft surface of the bolt.
FIG. 3 is a diagram showing a schematic configuration of a second embodiment of a bolt gauge to which the present invention is applied, and is a sectional view of the bolt showing a state in which a sensor portion is embedded in a hole formed in the bolt.
FIG. 4 is a diagram showing a schematic configuration of a third embodiment of a bolt gauge to which the present invention is applied, and a cross section of the bolt showing a state in which the first and second sensor portions are embedded in holes formed in the bolt; FIG.
FIG. 5 is a diagram showing a schematic configuration of a third embodiment of a bolt gauge to which the present invention is applied, in which a first sensor portion is embedded in a hole formed in the bolt, and a second shaft surface of the bolt is It is a side view of the volt | bolt which shows the state which affixed the sensor part.
FIG. 6 is a diagram showing a schematic configuration of a third embodiment of a bolt gauge to which the present invention is applied, in which a first sensor portion is embedded in a hole formed in the bolt, and a second shaft surface of the bolt is It is a side view of the volt | bolt which shows the state which affixed the sensor part.
FIG. 7 is a diagram showing a schematic configuration of a fourth embodiment of a bolt gauge to which the present invention is applied in an enlarged state of a head portion of the bolt, in a state where a sensor portion is embedded in a hole formed in the bolt; It is a figure which shows the part of a volt | bolt and a cover in a cross section.
FIG. 8 is a diagram showing a schematic configuration of a fifth embodiment of a bolt gauge to which the present invention is applied, and is a sectional view of the bolt showing a state in which a sensor portion is embedded in a hole formed in the bolt.
FIG. 9 is a diagram showing a schematic configuration of a sixth embodiment of a bolt gauge to which the present invention is applied, and is a sectional view of a bolt showing a configuration using a connector as a connecting member provided in a transmission section.
FIG. 10 is a diagram showing a schematic configuration of a sixth embodiment of a bolt gauge to which the present invention is applied, and is a sectional view of a bolt showing a configuration using a ferrule or a sleeve as a connecting member provided in a transmission unit; is there.
FIG. 11 is a diagram showing a schematic configuration of a seventh embodiment of a bolt gauge to which the present invention is applied in an enlarged state of a head portion of the bolt, and a configuration for performing optical connection using a collimator lens; It is a figure which shows the part of a volt | bolt and a cover in a cross section.
FIG. 12 is a diagram showing a schematic configuration of a seventh embodiment of a bolt gauge to which the present invention is applied in an enlarged state of a head portion of the bolt, and a configuration for optical connection using a Fresnel lens. It is a figure which shows the part of a volt | bolt and a cover in a cross section.
FIG. 13 shows a bolt gauge to which the present invention is applied. Reference example It is a perspective view which shows schematic structure of these.
FIG. 14 is obtained by applying the present invention. Reference example It is a perspective view which shows the form of the columnar member in the bolt gauge of this, and how to attach the sensor part to the columnar member, (a) is the form which forms a hole in the columnar member and embeds the sensor part, (b) is the columnar member Is a view showing a form in which the sensor part is sandwiched and the sensor part is sandwiched, and (c) is a form in which the sensor part is attached to the surface of the columnar member.
FIG. 15 shows a bolt gauge to which the present invention is applied. Reference example It is a figure which shows schematic structure of these, and is a perspective view which shows the structure which provided the protective tube.
[Explanation of symbols]
1 bolt gauge
3 bolts
3a head
3b Shaft
5 Sensor part
7 Transmission section
9 External devices
11 holes
13 Protection tube

Claims (4)

  1. A sensor unit that is attached to the shaft of the bolt and generates an optical signal corresponding to the distortion of the bolt, an arithmetic unit that calculates strain based on the optical signal from the sensor unit, and an optical signal from the sensor unit to the arithmetic unit A transmission part formed of an optical fiber that transmits the sensor part, and is attached to a position corresponding to a hole formed in a head part of the bolt to which the sensor part is attached in a state of protruding from the surface of the head part of the bolt to which the sensor part is attached. In a bolt gauge comprising a protective tube through which an optical fiber forming the transmission unit is inserted ,
    The protective tube is provided in a state in which one end is in contact with the head surface of the bolt to which the sensor unit is attached, and the end of the protective tube in contact with the bolt to which the sensor unit is attached. A bolt gauge, comprising: a fixing member that covers at least a part of the head and fixes the protective tube to a bolt to which the sensor unit is attached.
  2. The end of the protective tube that is in contact with the surface of the head of the bolt to which the sensor unit is attached has a notch formed by notching the tube wall from the surface of the end. The bolt gauge according to claim 1 .
  3. A sensor unit that is attached to the shaft of the bolt and generates an optical signal corresponding to the distortion of the bolt, an arithmetic unit that calculates strain based on the optical signal from the sensor unit, and an optical signal from the sensor unit to the arithmetic unit A transmission part formed of an optical fiber that transmits the sensor part, and is attached to a position corresponding to a hole formed in a head part of the bolt to which the sensor part is attached in a state of protruding from the surface of the head part of the bolt to which the sensor part is attached. In a bolt gauge comprising a protective tube through which an optical fiber forming the transmission unit is inserted,
    It is attached to the head of the bolt to which the sensor unit is attached, and includes a cover that forms a space between the head of the bolt and the protective tube is attached to the cover in a state of protruding from the cover A correction sensor unit that generates an optical signal corresponding to the distortion of the cover is attached to the inner surface of the cover, and the arithmetic unit is configured to respond to an optical signal from the correction sensor unit, features and to Rubo Rutogeji to become performing correction of the calculated value based on the light signal from the shaft portion and the sensor unit attached to the bolt.
  4. A sensor unit that is attached to the shaft of the bolt and generates an optical signal corresponding to the distortion of the bolt, an arithmetic unit that calculates strain based on the optical signal from the sensor unit, and an optical signal from the sensor unit to the arithmetic unit A transmission unit formed of an optical fiber that transmits the first and second lenses, each of the first and second lenses provided at the ends of the optical fibers facing each other of the divided transmission unit, and the sensor unit. And a cover that forms a space between the head of the bolt and a surface of the bolt.
    The first lens is provided at an end portion of the transmission portion on the side connected to the sensor portion, and is attached to a head of a bolt to which the sensor portion is attached, and the second lens is The cover is provided at an end of the transmission unit connected to the arithmetic unit, and the cover is in a state of facing the first lens in a space formed in the cover. A bolt gauge that supports the second lens.
JP2003176065A 2003-06-20 2003-06-20 Bolt gauge Expired - Fee Related JP4318113B2 (en)

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