JP5712016B2 - Bolt acting force measuring device - Google Patents

Description

  The present invention relates to an apparatus for measuring a force acting on a bolt fastened to an object using a strain gauge.

  In various devices such as vehicles and machines, the force acting on the tightened bolt (hereinafter referred to as the bolt acting force) to prevent the bolt used for fastening the object from being damaged or loosened. Is often required to manage). In such a case, it is necessary to measure the actual bolt acting force in designing the device.

  In this case, if a strain gauge can be attached to the surface of the bolt, the bolt acting force can be measured via the strain gauge attached to the surface. In many cases, the strain gauge cannot be attached to the surface of the bolt due to the bolt fastening structure.

  In such a case, for example, as seen in Patent Document 1, a small-diameter hole (hereinafter sometimes referred to as a bolt hole) drilled in advance from the top surface of the bolt head to the bolt shaft is strained. A device having a structure in which the gauge is inserted and the strain gauge is fixed to the bolt by an adhesive filled in the bolt hole is used.

JP-A-6-347349

  In the conventional apparatus as shown in Patent Document 1, the operation of inserting the strain gauge into the bolt hole is performed by holding a cable connected to a thin lead wire led out from the strain gauge. In this case, the lead wire led out from the strain gauge is easily bent due to contact between the strain gauge and the inner peripheral surface of the bolt hole.

  For this reason, in the conventional apparatus as seen in Patent Document 1, it is difficult to keep the distance between the cable and the strain gauge constant when the strain gauge is inserted into the bolt hole. It has been difficult to insert an appropriate required position for measuring the acting force.

  Further, in order to make it easier for the strain gauge to enter the bolt hole, for example, when the bolt hole is formed with a large inner diameter, the strain gauge is easily inclined with respect to the axial direction of the bolt. As a result, there is an inconvenience that it is difficult to accurately measure the bolt acting force to be measured.

  The present invention has been made in view of such a background, and a strain gauge arranged at a required position in a bolt hole drilled in a bolt for measuring a bolt acting force can be easily reached to the required position. It is another object of the present invention to provide a device for measuring the acting force of a bolt that can be inserted into a bolt hole in a stable posture, and that enables accurate measurement of the acting force of the bolt.

The bolt acting force measuring device of the present invention is a device that is assembled to a bolt to measure a bolt acting force, which is a force acting on a bolt fastened to an object, in order to achieve such an object. It is formed so as to extend linearly, and is previously drilled in the axial direction of the bolt from the top surface of the head of the bolt to the axial portion of the bolt in order to measure the bolt acting force. A rod member into which a portion on one end side is inserted into a bolt hole, which is a hole, a strain gauge fixed to a side surface of the portion of the rod member to be inserted into the bolt hole, and a measurement lead derived from the strain gauge Wires and side surfaces of the rod member are attached at predetermined unit length intervals in the longitudinal direction of the rod member so that the position of the strain gauge relative to the rod member in the longitudinal direction of the rod member can be grasped. And a prime, with one end portion of the rod member such that the strain gauge at a predetermined position in the axial direction of the bolt is disposed in the bolt hole is inserted into the bolt holes, the characterized in that said rod member and said strain gauge is fixed to the bolt by an adhesive filled in the bolt hole.

  According to the present invention, since the rod member having the strain gauge fixed to the side surface has rigidity, it is difficult to bend. For this reason, by grasping the portion on the other end side of the rod member and inserting the rod member into the bolt hole, the strain gauge can be easily attached while keeping the position and posture of the strain gauge with respect to the rod member constant. Can be inserted into the bolt hole.

  Furthermore, since the rod member extends in the bolt hole, the longitudinal direction of the rod member is suppressed from being inclined with respect to the axial direction of the bolt. As a result, the strain gauge is also prevented from tilting with respect to the axial direction of the bolt.

  Moreover, since the scale is attached to the side surface of the rod member, the position of the strain gauge with respect to the rod member can be grasped based on the scale. For this reason, even when the strain gauge is inserted into the bolt hole when the one end side portion of the rod member is inserted into the bolt hole together with the strain gauge, the position of the strain gauge relative to the bolt is based on the scale. The relationship can be easily grasped. As a result, the strain gauge can be accurately arranged at a predetermined position in the bolt hole, and in this state, the strain gauge can be fixed to the bolt together with the rod member by the adhesive.

  Therefore, according to the present invention, the strain gauge can be inserted into the bolt hole in an easy and stable posture up to a required position in the bolt hole. Since the strain gauge can be arranged in a proper posture at a required position in the bolt hole, the reliability of the strain gauge detection signal with respect to the bolt acting force to be measured can be ensured. Based on the detection signal, it is possible to accurately measure the bolt acting force.

  In this invention, the rod member is preferably a member made of the same material as the adhesive filled in the bolt hole.

  According to this, the adhesive filled in the bolt hole and the rod member can be integrated uniformly. For this reason, the bolt action force which acts on the bolt fastened to the object can be appropriately transmitted to the strain gauge in the bolt hole. As a result, the reliability of the measurement of the bolt acting force based on the detection signal of the strain gauge can be enhanced.

  Moreover, in the said invention, in order to arrange | position a strain gauge in the predetermined position in a bolt hole, the following assembly | attachment forms are employable.

  In the one assembling form, the strain gauge is fixed to the rod member at a position near one end of the rod member, and a portion on one end side of the rod member is connected to the strain gauge indicated by the scale and the strain gauge. The bolt hole is inserted into the bolt hole so that the distance from the opening end of the bolt hole is a predetermined distance.

  In this case, when the portion on one end side of the rod member is inserted into the bolt hole, the interval between the strain gauge and the opening end of the bolt hole can be reliably grasped by the scale, so that the opening of the strain gauge and the bolt hole is The rod member can be inserted into the bolt hole so that the distance between the ends accurately matches the predetermined distance. Thereby, a strain gauge can be accurately arrange | positioned in the predetermined position in a bolt hole with respect to various various sizes and types of bolts.

  Alternatively, in another assembling form, the rod member is separated by cutting the rod member in a transverse direction before being inserted into the bolt hole, and the rod member after the cutting is cut. One end of the rod member is inserted into the bolt hole so as to abut against the bottom surface of the bolt hole, and the cutting of the rod member is the interval between the one end of the rod member after the cutting indicated by the scale and the strain gauge. Are performed at predetermined intervals.

  In this case, the cutting position of the rod member can be accurately determined based on the scale so that the distance between the one end of the rod member after cutting and the strain gauge becomes a predetermined distance. For this reason, after cutting the rod member, by inserting one end of the rod member into the bolt hole so as to be in contact with the bottom surface of the bolt hole, the distance between the bottom surface of the bolt hole and the strain gauge is reduced in the bolt hole. Strain gauges can be accurately arranged at the predetermined intervals. Thereby, a strain gauge can be accurately arrange | positioned in the predetermined position in a bolt hole with respect to various various sizes and types of bolts.

The figure which shows the structure of the apparatus for measuring the action force of the volt | bolt in one Embodiment of this invention. The figure which shows the state which assembled | attached the bolt for the action force measurement of FIG. 1 to the volt | bolt by the 1st assembly | attachment form. The figure which shows the state which assembled | attached the bolt for the action force measurement of FIG. 1 to the volt | bolt by the 2nd assembly | attachment form.

  An embodiment of the present invention will be described below with reference to FIGS.

  As shown in FIG. 1, the bolt force measuring apparatus 1 according to the present embodiment includes a rod member 2 and a strain gauge 3 as main components, and the rod member 2 and the strain gauge 3 are The bolt A is assembled to a bolt A to be measured.

  In order to assemble the rod member 2 and the strain gauge 3, a screw is formed on the outer peripheral surface from the top surface (upper end surface) of the head A <b> 1 of the bolt A in advance. A hole A3 (hereinafter referred to as a bolt hole A3) is bored coaxially with the bolt A up to the shaft portion A2. The inner diameter of the bolt hole A3 is, for example, about 2 mm.

  The rod member 2 is a rod-like or hollow pipe-like member formed so as to extend linearly (in a certain direction), and its total length is longer than the depth of the bolt hole A3. The outer diameter of the rod member 2 is smaller than the inner diameter of the bolt hole A3. The outer diameter is, for example, about 1.6 mm.

  Therefore, the rod member 2 accommodates a part on one end side (a part on the lower end side in FIG. 1) inside the bolt hole A3, and a part on the other end side (a part on the upper end side in FIG. 1) as a bolt hole. It can be inserted into the bolt hole A3 so as to protrude from A3 to the outside.

  The rod member 2 is made of the same material as the adhesive 5 described later filled in the bolt hole A3 and has rigidity. The material is, for example, epoxy, polyimide, acrylic, phenol or the like.

  A plurality of line-shaped scales 4 are attached to the side surface of the rod member 2 so as to be arranged at predetermined unit length intervals (for example, 1 mm intervals) in the longitudinal direction of the rod member 2.

  The strain gauge 3 is formed by forming a sensing part 3b made of a resistor on a gauge base 3a as a base, and the gauge base 3a is located near one end of the rod member 2 (closed to the lower end in FIG. 1). The rod member 2 is bonded to the side surface of the rod member 2 with an adhesive (not shown). Thereby, the strain gauge 3 is fixed to the side surface of the rod member 2.

  In the acting force measuring device 1 of the illustrated example, the rod member 2 is formed in a cylindrical shape. For this reason, the gauge base 3a of the strain gauge 3 is fixed to the outer peripheral surface of the rod member 2 in a rounded shape.

  However, the rod member 2 is formed in a prismatic shape or a flat plate shape, or a part of the side surface of the rod member 2 is formed in a flat surface shape, and the flat surface portion on the side surface of the rod member 2 is formed in a flat plate shape. A strain gauge having a gauge base may be fixed.

  In the example of this embodiment, the bolt acting force to be measured is an acting force acting in the axial direction of the bolt A, for example. For this reason, the sensitive part 3b of the strain gauge 3 detects the strain due to the acting force in the longitudinal direction of the rod member 2 (in other words, has sensitivity to the acting force in the longitudinal direction of the rod member 2). Is formed.

  The strain gauge 3 is fixed to the rod member 2 so that the position in the longitudinal direction of the rod member 2 can be specified (ascertained) based on a scale 4 attached to the rod member 2.

  Specifically, the representative position of the strain gauge 3, for example, the center position C of the sensitive part 3b of the strain gauge 3 indicated by a dashed line C in FIG. 1 (or the position of one end of the sensitive part 3b of the strain gauge 3). ) Is a predetermined interval in which the position (interval in the longitudinal direction of the rod member 2) between any one line segment of the scale 4 or any one line segment of the scale 4 is predetermined. The gauge base 3a of the strain gauge 3 is fixed to the rod member 2 so as to match the position.

  Thereby, the distance in the longitudinal direction of the rod member 2 (in other words, the longitudinal direction of the rod member 2) between each scale 4 (each line segment of the scale 4) and the sensing part 3 b of the strain gauge 3. The relative position of the sensitive part 3b of the strain gauge 3 with respect to the individual scales 4 in the direction can be specified (obtained) by the scales 4. For example, in the apparatus 1 for measuring the acting force in the illustrated example, the center position C of the sensitive part 3b of the strain gauge 3 is spaced downward from the scale 4x by 10 scale intervals (interval 10 times the unit length of 1 scale). ) Can be grasped.

  In addition, a measurement lead wire 3 c is connected in advance to the sensing part 3 b of the strain gauge 3, and the measurement lead wire 3 c is led out from the strain gauge 3. The measurement lead wire 3c is for connecting the strain gauge 3 to a measuring instrument (electronic circuit unit) (not shown) for processing the detection signal (detection signal corresponding to the strain) of the strain gauge 3. The measuring instrument is a known one, and a circuit for converting a detection signal of the strain gauge 3 into a detection signal of an acting force (for example, a resistance circuit for constituting a Wheatstone bridge circuit including the strain gauge 3), or a circuit thereof And an arithmetic processing circuit for processing the output signal.

  The number of measurement lead wires 3c derived from the strain gauge 3 is two in the illustrated example, but the number of the measurement lead wires 3c is a circuit for converting the detection signal of the strain gauge 3 into the detection signal of the acting force. It is defined according to the configuration form, the number of sensing parts 3b, and the like.

  The rod member 2 and the strain gauge 3 of the working force measuring device 1 configured as described above are assembled to the bolt A, as described below, whereby the bolt acting force of the bolt A can be measured. It becomes possible. The assembling form is roughly divided into two kinds of assembling forms, a first assembling form described with reference to FIG. 2 and a second assembling form described with reference to FIG.

  First, referring to FIG. 2, in the first assembly form of the rod member 2 and the strain gauge 3 with respect to the bolt A, one end of the rod member 2 is brought into contact with the bottom surface of the bolt hole A3. In this embodiment, the rod member 2 and the strain gauge 3 are assembled to the bolt A so as to be disposed in the bolt hole A3 at a position spaced apart from the bottom surface of the bolt hole A3 in the axial direction of A.

  More specifically, in the first assembly mode, as shown in FIG. 2, the target arrangement position of the strain gauge 3 in the bolt hole A3 is, for example, the sensing portion 3b as a representative position of the strain gauge 3. The center position C is a position where a predetermined distance D1 exists in the axial direction of the bolt A from the bottom surface of the bolt hole A3. The position is a position determined in advance according to the size or type of the bolt A as a position where the bolt acting force on the bolt A can be appropriately measured.

  Here, the device 1 for measuring the acting force according to the present embodiment is not dedicated to the bolt A of a specific size or type, and is used for measuring the bolt acting force of various types of bolts A of various sizes and types. It is supposed to be general purpose. Therefore, the distance Da from one end (the lower end in FIG. 1) of the rod member 2 of the device 1 for measuring the acting force shown in FIG. 1 to the center position C of the sensing part 3b of the strain gauge 3 measures the bolt acting force. It is not set to a dedicated interval for the bolt A to be tried. For this reason, as shown in FIG. 2, the interval Da generally does not coincide with the predetermined interval D1, and may be longer than the predetermined interval D1.

  Supplementally, when Da <D1, the first assembly form cannot be employed, and the second assembly form described later is employed.

  As described above, when Da> D1, before assembling the bolt member 2 and the strain gauge 3 to the bolt A, the distance from one end of the rod member 2 to the center position C of the sensing part 3b of the strain gauge 3 The rod member 2 is cut (to adjust the distance between one end of the rod member 2 and the center position C of the sensing part 3b of the strain gauge 3 so as to match the predetermined distance D1. Is cut).

  In this cutting process, the rod member 2 is at a position near one end (position between one end and the strain gauge 3) in the transverse direction of the rod member 2 (direction substantially perpendicular to the longitudinal direction of the rod member 2). A portion (a portion indicated by a two-dot chain line 2a in FIG. 2) from the cutting position to one end of the rod member 2 is cut off from the rod member 2. The cutting operation is performed using an appropriate tool such as a cutter or a scissors.

  The cutting position of the rod member 2 in this cutting process is the position having the predetermined distance D1 on the one end side of the rod member 2 from the center position C of the sensing part 3b of the strain gauge 3, or the initial rod before cutting. It is determined based on the scale 4 as a position having an interval of (Da-D1) from one end of the member 2 to the strain gauge 3 side.

  Thereby, the rod member 2 is cut so that the interval between one end of the rod member 2 after cutting and the center position C of the sensing part 3b of the strain gauge 3 coincides with the predetermined interval D1.

  In the first assembling mode, the distance Da between one end of the rod member 2 of the initial apparatus 1 for measuring an acting force 1 shown in FIG. 1 and the center position C of the sensing part 3b of the strain gauge 3 is Da> D1. In this case, the rod member 2 is cut as described above. Then, after this cutting process, the measurement lead wire 3c extends from the strain gauge 3 toward the other end of the rod member 2 so as to be along the rod member 2, while the rod member 2 The end portion (portion shown by the two-dot chain line 2b in FIG. 2) is gripped, and in this state, the one end portion of the rod member 2 together with the strain gauge 3 fixed thereto is bolt hole of the bolt A. Inserted into A3.

  Note that a distance Da between one end of the original rod member 2 before cutting the one end of the rod member 2 and the center position C of the sensing part 3b of the strain gauge 3 coincides with the predetermined distance D1 (or In the case of substantially matching), the cutting process of one end portion of the rod member 2 is omitted. In this case, the part on the one end side of the original rod member 2 shown in FIG. 1 is inserted into the bolt hole A3 of the bolt A together with the strain gauge 3.

  In the first assembly mode, the rod member 2 and the strain gauge 3 are inserted into the bolt hole A3 while the longitudinal direction of the rod member 2 is maintained substantially in the same direction as the axial direction of the bolt A. This is performed until one end of the rod member 2 comes into contact with the bottom surface of the bolt hole A3. Thereby, the strain gauge 3 is arrange | positioned in the bolt hole 3 so that the center position C of the sensitive part 3b of the strain gauge 3 may become the position which exists in the said predetermined space | interval D1 from the bottom face of the bolt hole A3. Further, a portion on the other end side of the rod member 2 (portion indicated by a two-dot chain line 2b in FIG. 2) projects to the outside of the bolt hole A3 together with the measurement lead wire 3c along the portion.

  In this case, since the rod member 2 has rigidity, the rod member 2 is bent and deformed even when the rod member 2 and the strain gauge 3 come into contact with the inner peripheral surface of the bolt hole A3 when inserted into the bolt hole A3. It is kept in a substantially linear shape. The strain gauge 3 is fixed to the rod member 2. For this reason, the strain gauge 3 can be easily inserted together with the rod member 2 into the bolt hole A3.

  Further, since the strain gauge 3 fixed to the rod member 2 is maintained at a fixed position and posture with respect to the rod member 2, the strain gauge 3 is strained by the contact of one end of the rod member 2 with the bottom surface of the bolt hole A3. It is possible to accurately arrange the gauge 3 at an appropriate position within the bolt hole 3 (a position where the center position C of the sensing part 3b of the strain gauge 3 is at the predetermined distance D1 from the bottom surface of the bolt hole A3). it can.

  Further, since the rod member 2 extends over the entire length of the bolt hole A3, the longitudinal direction of the rod member 2 can be accurately aligned with the axial direction of the bolt A. For this reason, it is suppressed that the direction of the strain gauge 3 tilts with respect to the axial center direction of the bolt A, and the sensitivity direction of the sensing part 3b of the strain gauge 3 is set to the bolt acting force (in the present embodiment). In the example, when measuring the acting force in the axial direction of the bolt A, it can be made to coincide with a suitable direction with high accuracy.

  The rod member 2 and the strain gauge 3 inserted into the bolt hole A3 of the bolt A as described above are further fixed to the bolt A by the adhesive 5 that is filled and cured in the bolt hole A3. The material of the adhesive 5 is the same as that of the rod member 2 as described above (for example, epoxy, polyimide, acrylic, phenol, etc.). The bolt hole A3 may be filled with the adhesive 5 in a molten state before curing before the rod member 2 and the strain gauge 3 are inserted into the bolt hole A3.

  In this case, since the rod member 2 is made of the same material as that of the adhesive 5, the adhesive 5 filled in the bolt hole A3 and hardened, and the rod member 2 are uniformly integrated. For this reason, it is possible to appropriately transmit the bolt acting force acting on the bolt A from the object W or the like to the sensing part 3b of the strain gauge 3 with the bolt A fastened to the object W.

  In the first assembling mode, the rod member 2 and the strain gauge 3 are assembled to the bolt A for which the bolt acting force is to be measured as described above.

  In this embodiment, after the rod member 2 and the strain gauge 3 are assembled to the bolt A in this way, the position of the rod member 2 protruding from the bolt hole A3 is close to the opening end of the bolt hole A3. Then, the rod member 2 is cut in the transverse direction. This cutting operation is performed using an appropriate tool such as a cutter or a scissors, similarly to the cutting operation of one end of the rod member 2.

  As a result, the portion on the other end side of the rod member 2 in FIG. 2 (the portion indicated by the two-dot chain line 2b in FIG. 2) is separated from the portion inserted in the bolt hole A3. The part 2b on the other end side of the rod member 2 is cut off in this way so that the rod member 2 does not get in the way during the fastening (screw fastening) of the bolt A to the object W or the fastening release operation. is there.

  Next, the bolt A assembled with the rod member 2 and the strain gauge 3 as described above is fastened to the object W. Then, the measurement lead wire 3 c led out from the strain gauge 3 is connected to a measuring instrument (not shown), and the bolt acting force is measured based on the detection signal of the strain gauge 3.

  Next, a second assembly form will be described with reference to FIG. In this second assembling mode, the strain gauge 3 is bolted at a position at a predetermined interval from the opening end of the bolt hole A3 in the axial direction of the bolt A (in other words, from the top surface of the head A1 of the bolt A). In this mode, the rod member 2 and the strain gauge 3 are assembled to the bolt A so as to be disposed in the hole A3.

  More specifically, in the second assembly mode, as shown in FIG. 3, the target position of the strain gauge 3 is, for example, the center position C as the representative position of the sensing part 3b of the strain gauge 3, From the opening end of the bolt hole A3, a predetermined distance D2 exists in the axial direction of the bolt A. The position is a position determined in advance according to the size or type of the bolt A as a position where the bolt acting force on the bolt A can be appropriately measured.

  In the second assembly mode, the measurement lead wire 3c extends along the rod member 2 so as to extend from the strain gauge 3 toward the other end side (the upper end side in FIG. 3) of the rod member 2. While doing so, a portion on the other end side of the rod member 2 (portion indicated by a two-dot chain line 2c in FIG. 3) is gripped, and in this state, a portion on one end side of the rod member 2 (a portion on the lower end side in FIG. 3). Is inserted into the bolt hole A3 of the bolt A together with the strain gauge 3 fixed thereto.

  In this case, in the second assembling mode, the rod member 2 and the strain gauge 3 are inserted into the bolt hole A3 so that the longitudinal direction of the rod member 2 is maintained in substantially the same direction as the axial direction of the bolt A. On the other hand, the position on the rod member 2 specified in advance based on the scale 4 as the position having the predetermined distance D2 from the center position C of the sensing part 3b of the strain gauge 3 to the other end side of the rod member 2 is a bolt hole. The process is performed until it coincides with the position of the opening end of A3. And the position on the rod member 2 which has the said predetermined space | interval D2 in the other end side of the rod member 2 from the center position C of the sensitive part 3b of the strain gauge 3 corresponds to the position of the opening end of the bolt hole A3. Thus, the rod member 2 is stationary and held.

  Thereby, the strain gauge 3 is arrange | positioned in the bolt hole 3 so that the center position C of the sensitive part 3b of the strain gauge 3 may become the position which exists in the said predetermined space | interval D2 from the opening end of bolt hole A3. Further, a portion on the other end side of the rod member 2 (portion indicated by a two-dot chain line 2c in FIG. 3) protrudes outside the bolt hole A3 together with the measurement lead wire 3c along the portion.

  In this case, as in the case of the first assembly form, the rod member 2 has rigidity, so that the rod member 2 and the strain gauge 3 come into contact with the inner peripheral surface of the bolt hole A3 when inserted into the bolt hole A3. Even so, the rod member 2 is not bent and deformed, and is maintained in a substantially linear shape. The strain gauge 3 is fixed to the rod member 2. For this reason, the strain gauge 3 can be easily inserted together with the rod member 2 into the bolt hole A3.

  And since the strain gauge 3 fixed to the rod member 2 is maintained at a fixed position and posture with respect to the rod member 2, the open end of the bolt hole A3 when the rod member 2 is inserted into the bolt hole A3. And the center position C of the sensing part 3 b of the strain gauge 3 can be accurately grasped by the scale 4. As a result, the strain gauge 3 is inserted into the bolt hole 3 so that the center position C of the sensing part 3b of the strain gauge 3 accurately coincides with the position having the predetermined distance D2 from the opening end of the bolt hole A3. Can be arranged.

  Moreover, since the length of the part arrange | positioned in the bolt hole A3 of the rod member 2 becomes close to the depth of the bolt hole A3, the longitudinal direction of the rod member 2 is accurately made into the axial direction of the bolt A. Can be along. For this reason, it is suppressed that the direction of the strain gauge 3 tilts with respect to the axial center direction of the bolt A, and the sensitivity direction of the sensing part 3b of the strain gauge 3 is set to the bolt acting force (in the present embodiment). In the example, when measuring the acting force in the axial direction of the bolt A, it can be made to coincide with a suitable direction with high accuracy.

  Supplementally, the total length (Da + D2) of the distance Da from one end (the lower end in FIG. 1) of the rod member 2 shown in FIG. 1 to the center position C of the sensing part 3b of the strain gauge 3 and the predetermined distance D2 is described above. ) May be longer than the depth of the bolt hole A3.

  In such a case, when the bolt member 2 and the strain gauge 3 are assembled to the bolt A in the second assembling form, the central position of the sensing part 3b of the strain gauge 3 from one end of the rod member 2 before the assembly. What is necessary is just to cut the one end part of the rod member 2 so that the sum total length of the space | interval to C and the predetermined space | interval D2 may become shorter than the depth of bolt hole A3. And the cutting process should just be performed using appropriate tools, such as a cutter and a scissors, like the case where the one end part of the rod member 2 is cut | disconnected by the 1st assembly | attachment form.

  As described above, the rod member 2 and the strain gauge 3 inserted into the bolt hole A3 of the bolt A are further filled with the bolt hole A3 and hardened similarly to the case of the first assembled form. Is fixed to the bolt A.

  In this case, since the rod member 2 is made of the same material as that of the adhesive 5, the adhesive 5 that is filled and cured in the bolt hole A3 and the rod member 2 are uniform as in the first assembly mode. Integrated. For this reason, it is possible to appropriately transmit the bolt acting force acting on the bolt A from the object W or the like to the sensing part 3b of the strain gauge 3 with the bolt A fastened to the object W.

  In the second assembling mode, the rod member 2 and the strain gauge 3 are assembled to the bolt A to be measured for the bolt acting force as described above.

  Then, after assembling the rod member 2 and the strain gauge 3 to the bolt A in this manner, the portion of the rod member 2 protruding from the bolt hole A3 is the same as that of the bolt hole A3, as in the first assembled form. The rod member 2 is cut in the transverse direction at a position close to the open end. Thereby, the part (the part shown with the dashed-two dotted line 2c of FIG. 3) of the other end side of the rod member 2 of FIG. 3 is cut | disconnected from the part inserted in bolt hole A3.

  Next, the bolt A assembled with the rod member 2 and the strain gauge 3 as described above is fastened to the object W. Then, the measurement lead wire 3 c led out from the strain gauge 3 is connected to a measuring instrument (not shown), and the bolt acting force is measured based on the detection signal of the strain gauge 3.

  Supplementally, regarding the processing of the measurement lead wire 3c after the rod member 2 and the strain gauge 3 are assembled to the bolt A in any of the first assembling mode and the second assembling mode, for example, A terminal board is fixed to the top surface of the head A1 of the bolt A, and a measurement lead wire 3c is connected to the terminal board, and a connection cable drawn from the terminal board is connected to the connection cable via the terminal board. The lead wire 3 may be made conductive. Then, when measuring the bolt action force, the connection cable may be connected to a measuring instrument. In this case, the measurement lead wire 3c may be fixed to the terminal substrate by molding with an adhesive.

  As described above, according to the working force measurement device 1 of the present embodiment, the strain gauge 3 is attached to the bolts A of various sizes and types according to the first assembly mode or the second assembly mode. Thus, it can be easily placed in a proper position with high accuracy at a predetermined position of the bolt hole A3. For this reason, the assembly | attachment operation | work of the strain gate 3 with respect to the volt | bolt A can be performed efficiently in a short time. Further, the bolt acting force can be measured with high reliability based on the detection signal of the strain gauge 3.

  DESCRIPTION OF SYMBOLS 1 ... Acting force measuring apparatus, 2 ... Rod member, 3 ... Strain gauge, 3c ... Measuring lead wire, 4 ... Scale, 5 ... Adhesive, A ... Bolt, A1 ... Head, A2 ... Shaft part, A3 ... Bolt hole, W ... object.

Claims (4)

A device assembled to a bolt to measure a bolt acting force, which is a force acting on a bolt fastened to an object,
It is formed so as to extend linearly, and is previously drilled in the axial direction of the bolt from the top surface of the head of the bolt to the axial portion of the bolt in order to measure the bolt acting force. A rod member into which a portion on one end side is inserted into a bolt hole which is a hole;
A strain gauge fixed to the side surface of the portion inserted into the bolt hole of the rod member;
A measurement lead wire derived from the strain gauge;
A scale is provided on a side surface of the rod member at predetermined unit length intervals in the longitudinal direction of the rod member so that the position of the strain gauge with respect to the rod member in the longitudinal direction of the rod member can be grasped. ,
A portion on one end side of the rod member is inserted into the bolt hole so that the strain gauge is disposed in the bolt hole at a predetermined position in the axial direction of the bolt, and the bolt hole is filled. bolts acting force measuring device, wherein a said rod member and said strain gauge is fixed to the bolt by an adhesive to be. The device for measuring the acting force of a bolt according to claim 1,
The rod member is a member made of the same material as the adhesive filled in the bolt hole, and is an apparatus for measuring the acting force of a bolt. In the apparatus for measuring the acting force of the bolt according to claim 1 or 2,
The strain gauge is fixed to the rod member at a position near one end of the rod member, and a portion on one end side of the rod member is formed between the strain gauge indicated by the scale and the opening end of the bolt hole. A device for measuring an acting force of a bolt, wherein the bolt is inserted into the bolt hole so that a predetermined interval is a predetermined interval. In the apparatus for measuring the acting force of the bolt according to claim 1 or 2,
Before the rod member is inserted into the bolt hole, one end of the rod member is cut off by cutting the rod member in the transverse direction, and one end of the rod member after the cutting is connected to the bottom surface of the bolt hole. The rod member is inserted into the bolt hole so as to be in contact with the rod member, and the interval between the one end of the rod member after the cutting indicated by the scale and the strain gauge is set to a predetermined value. An apparatus for measuring the acting force of a bolt, characterized in that the bolt is applied at intervals.

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