JP2005221254A - Axial force measuring instrument, axial force measuring device and axial force measuring method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an axial force measuring instrument, an axial force measuring device and an axial force measuring method capable of measuring the axial force when fastening onto an object a member to be fastened used actually by using a screw member used actually. <P>SOLUTION: When fastening the member to be fastened by the screw member onto a prescribed shaft, a groove part having a detection surface parallel to the direction wherein the screw member applies the axial force is formed on a shaft member of this axial force measuring instrument for measuring the axial force generated in the axial direction of the screw member, and a detection member is provided on the detection surface of the groove part, and a strain of the shaft member is detected. Then, this axial force measuring method for calculating the axial force by performing prescribed processing based on the detected strain is applied to this axial force measuring device equipped with the axial force measuring instrument. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an axial force measuring instrument, an axial force measuring device, and an axial force measuring method.

Conventionally, when fixing a member to be fastened to an object such as a shaft, they are sometimes fastened and fixed by a screw member such as a screw or a bolt.
FIG. 11 shows a state in which the fastened member S is fastened to the object T by a bolt B having a screw head h. In order to manage the fixing strength due to the fastening, there is known a method for measuring the axial force generated in the axial direction of the bolt B based on the fastening torque applied to the bolt B when they are fastened.
In FIG. 12, the strain gauge 20 is attached to the surface of the bolt B, and the lead wire L connected to the strain gauge 20 is inserted into the through hole 9 formed in the screw head h. FIG. 13 shows the strain gauge 20 attached to the inner surface of the pore 99 formed along the axis of the bolt B. The axial force is measured by the strain gauge 20 detecting the amount of elongation as the amount of distortion of the bolt B due to the axial force generated when the bolt B fastens the fastened member S and the object T. It has become.
Further, FIG. 14 shows that the ultrasonic wave is applied by the ultrasonic vibrator C to the bolt B that fastens the member to be fastened S and the object T, and the reflected ultrasonic wave is detected to thereby detect the bolt B. The amount of strain is obtained and the axial force is measured.
Further, FIG. 15 shows that a piezoelectric pressure sensor called a load washer W is disposed between the fastened member S and the target T, and the bolt B is loaded when the fastened member S and the target T are fastened. The axial force is measured by detecting the force with which the washer W is tightened.

Further, when the second shaft, which is the object, is fastened and fixed to the first shaft as the fastened member with a nut, the strain gauge affixed to the surface of the second shaft is used to fix the second shaft. A method of detecting the amount of strain and measuring the axial force is known (for example, see Patent Document 1).
JP 2000-32157 A

  However, in the case of the prior art as shown in FIGS. 12 to 15, the bolt B to be fastened has a screw head h, and the seat surface on which the screw head h faces the fastened member S is fastened. Since an axial force is generated as a reaction force of the force that presses the member S, the axial force can be measured, but in the case of fastening with a set screw 6 (commonly known as an imo screw) without a screw head as shown in FIG. Since there is no bearing surface, there is a problem that it is difficult to apply these measurement methods.

  Moreover, in the case of the prior art as shown in FIGS. 12 and 13, the bolt B is a bolt for detecting the amount of strain, so the axial force in the bolt that actually fastens the fastened member S and the object T, There is a problem that an error may occur between the measured axial force. Further, in the case of the prior art as shown in FIG. 15, since the load washer W for measuring the axial force is disposed between the member to be fastened S and the object T, the member to be fastened when actually fastening is performed. Since there is a difference from the arrangement of S and the object T, there is a problem that an error may occur between the axial force when the member to be fastened S and the object T are actually fastened and the measured axial force. there were.

  In the case of the prior art as shown in FIGS. 12 and 13, the strain gauge 20 cannot be attached to a small screw or bolt such as the set screw 6 without a screw head shown in FIG. There was a problem that it could not be applied. In the case of the prior art as shown in FIG. 14, there is a problem that it is difficult to apply to a small screw or bolt.

  Moreover, in the case of the above-mentioned Patent Document 1, it is good if a strain gauge can be attached to a position where strain due to axial force occurs, but if the strain gauge cannot be attached to such a position, the strain amount There is a problem that the detection cannot be performed and the axial force cannot be measured by this measuring method.

  An object of the present invention is to provide an axial force measuring instrument, an axial force measuring device, and an axial force measuring device capable of measuring an axial force at the time of fastening to a target object using a screw member that actually uses a fastened member to be fastened. It is to provide an axial force measurement method.

  In order to solve the above problems, the invention according to claim 1 is an axial force for measuring an axial force generated in an axial direction of a screw member when the member to be fastened is fastened to the predetermined shaft by the screw member. A measuring instrument comprising a shaft member formed with a groove portion having a detection surface parallel to a direction in which the screw member applies an axial force when the member to be fastened is fastened by the screw member, and a detection surface of the groove portion. And a detection member for detecting strain of the shaft member.

According to the first aspect of the present invention, the shaft member is formed with a groove portion having a detection surface parallel to the direction in which the screw member applies the axial force, and the detection member is provided on the detection surface of the groove portion. Therefore, the detection member can detect the distortion of the shaft member with high sensitivity. And axial force can be calculated | required by performing a predetermined process based on the detected distortion | strain.
Accordingly, the axial force when the fastening member that is actually fixed to the shaft member corresponding to the predetermined shaft is fastened by using the screw member that is actually used can be measured, which is closer to the actual fastening. The axial force in the state can be measured.

  The invention according to claim 2 is an axial force measuring instrument for measuring an axial force generated in the axial direction of the screw member when the member to be fastened is fastened to the predetermined shaft by the screw member. A groove portion having the same cross-sectional shape as the surface perpendicular to the axial direction of the shaft and having a detection surface parallel to the direction in which the screw member applies the axial force when the member to be fastened is fastened by the screw member is formed. A shaft member and a detection member that is provided on a detection surface of the groove and detects strain of the shaft member.

According to the second aspect of the present invention, the shaft member is formed with a groove portion having a detection surface parallel to the direction in which the screw member applies the axial force, and the detection member is provided on the detection surface of the groove portion. Therefore, the detection member can detect the distortion of the shaft member with high sensitivity. And axial force can be calculated | required by performing a predetermined process based on the detected distortion | strain.
In particular, since the shaft member has the same cross-sectional shape as the surface perpendicular to the axial direction of the predetermined axis, a screw member that is actually used is used as the member to be fastened to the predetermined axis. And can be fastened to the shaft member.
Accordingly, the axial force when the fastening member that is actually fixed to the shaft member corresponding to the predetermined shaft is fastened by using the screw member that is actually used can be measured, which is closer to the actual fastening. The axial force in the state can be measured.

  A third aspect of the present invention is the axial force measuring instrument according to the first or second aspect, wherein the load acting surface is perpendicular to the direction in which the axial force acts at the position where the screw member acts on the axial member. It is characterized by having.

According to the invention described in claim 3, while having the same effect as that of the invention described in claim 1 or 2, the shaft member has the axial force at a position where the screw member applies the axial force to the shaft member. Therefore, the axial force can be easily applied in a predetermined direction (for example, a direction toward the axial center of the shaft member).
Therefore, more accurate strain detection based on the axial force can be performed, and more accurate axial force measurement can be performed.

  According to a fourth aspect of the present invention, in the axial force measuring instrument according to any one of the first to third aspects, the axial center of the shaft member from the load acting surface is closer to both ends in the axial direction of the shaft member of the load acting surface. It has the recessed part dented in the side, It is characterized by the above-mentioned.

According to the invention of claim 4, while having the same effect as that of the invention according to any one of claims 1 to 3, the shaft member is disposed at both ends in the axial direction of the shaft member of the load acting surface. Since the concave portion that is recessed toward the axial center of the shaft member from the load acting surface is provided, the axial force acting on the load acting surface can be concentrated on the detection member, and the strain accompanying the axial force can be detected with high sensitivity.
Therefore, more accurate strain detection based on the axial force can be performed, and more accurate axial force measurement can be performed.

  Invention of Claim 5 is an axial force measuring instrument as described in any one of Claims 1-4. WHEREIN: While a groove part is formed in the position which opposes on both sides of the axis of a shaft member, each of a groove part The detection surface is provided with a detection member.

According to the fifth aspect of the present invention, the same effect as that of any one of the first to fourth aspects of the present invention can be achieved, and the groove portion is formed at a position facing the axis of the shaft member. In addition, a detection member is provided on each detection surface of the groove. That is, since the detection members provided on the respective detection surfaces are arranged at positions facing each other across the axis of the shaft member, the axial force acting on the shaft member can be detected with high sensitivity.
Therefore, more accurate strain detection based on the axial force can be performed, and more accurate axial force measurement can be performed.

  According to a sixth aspect of the present invention, in the axial force measuring instrument according to the fifth aspect of the present invention, there is provided a through-hole perpendicular to the detection surface that communicates with the groove portions facing each other across the axis of the shaft member.

According to the sixth aspect of the invention, the shaft member has the same effect as that of the fifth aspect of the invention, and the shaft member communicates with the groove portion opposed across the axis of the shaft member, and penetrates perpendicular to the detection surface. Since the hole is provided, the axial force acting on the load acting surface can be concentrated on the detection member, and the strain accompanying the axial force can be detected with high sensitivity.
Therefore, more accurate strain detection based on the axial force can be performed, and more accurate axial force measurement can be performed.

  The invention according to claim 7 is the axial force measuring instrument according to claim 6, further comprising a detection member that detects strain of the shaft member on a surface perpendicular to the axial direction of the shaft member in the through hole. To do.

According to the seventh aspect of the invention, the shaft member has the same effect as that of the sixth aspect of the invention, and the shaft member detects the strain of the shaft member on a surface perpendicular to the axial direction of the shaft member in the through hole. Therefore, the pair of detection members provided on the detection surface of the groove and the pair of detection members provided in the through hole are arranged with the angle shifted by 90 degrees.
Therefore, since the strain accompanying the axial force can be detected in different directions, the strain accompanying the axial force can be detected with high sensitivity. Moreover, the detection sensitivity of distortion can be improved by increasing the number of detection members.
Therefore, more accurate strain detection based on the axial force can be performed, and more accurate axial force measurement can be performed.

  The invention according to claim 8 is the axial force measuring instrument according to any one of claims 1 to 7, wherein the detection member is a strain gauge for detecting compressive strain in the shaft member.

According to the invention described in claim 8, the same effect as the invention described in any one of claims 1 to 7 is achieved, and the detection member is a strain gauge that detects a compressive strain in the shaft member. More preferably, the compressive strain in the shaft member can be detected, and the axial force can be measured more accurately.
Moreover, it can be set as a relatively inexpensive axial force measuring instrument.

  The invention according to claim 9 is the axial force measuring instrument according to any one of claims 1 to 8, wherein the shaft member has a shape set based on a finite element method.

According to the ninth aspect of the present invention, the shaft member has a shape set based on the finite element method (FEM) while exhibiting the same effect as that of the first aspect of the present invention. Therefore, the shape of the shaft member can be regarded as a predetermined shaft that actually fixes the fastened member.
Therefore, since it is possible to measure the axial force when fastening using a screw member that actually uses a fastened member that is actually fixed to a shaft member corresponding to a predetermined shaft, it is closer to actual fastening. The axial force in the state can be measured.

  According to a tenth aspect of the present invention, in the axial force measuring instrument according to any one of the first to ninth aspects, the shaft member is formed of the same material as the predetermined shaft.

According to the invention of claim 10, the same effect as that of the invention according to any one of claims 1 to 9 is achieved, and the shaft member is formed of the same material as the predetermined shaft. The shaft member can be regarded as a predetermined shaft that actually fixes the fastened member.
Therefore, since it is possible to measure the axial force when fastening using a screw member that actually uses a fastened member that is actually fixed to a shaft member corresponding to a predetermined shaft, it is closer to actual fastening. The axial force in the state can be measured.

  Invention of Claim 11 is an axial force measuring apparatus, Comprising: The detection signal based on the distortion which the axial force measuring instrument as described in any one of Claims 1-10 and the detection member of an axial force measuring instrument detected And a display unit for displaying the axial force obtained by the control unit.

According to the invention of claim 11, the axial force measuring device includes an axial force measuring instrument, a control unit, and a display unit, and the control unit detects based on the strain detected by the detection member of the axial force measuring instrument. The signal can be processed to determine the axial force. Therefore, the axial force can be easily measured by detecting the strain based on the axial force.
Further, since the display unit can display the axial force obtained by the control unit, the measured axial force can be easily recognized and confirmed.

  Invention of Claim 12 is an axial force measuring method, Comprising: When fastening a to-be-fastened member to the shaft member of the axial force measuring instrument as described in any one of Claims 1-10 with a screw member, The axial force generated in the axial direction of the screw member is measured based on the strain detected by the detection member.

According to the invention described in claim 12, the axial force measuring method is the axial direction of the screw member based on the strain detected by the detecting member when the member to be fastened is fastened to the shaft member of the axial force measuring instrument by the screw member. Can be measured.
Therefore, since it is possible to measure the axial force when fastening using a screw member that actually uses a fastened member that is actually fixed to a shaft member corresponding to a predetermined shaft, it is closer to actual fastening. The axial force in the state can be measured.

  A thirteenth aspect of the present invention is the axial force measuring method according to the twelfth aspect, wherein the tightening torque of the screw member when the fastened member is fastened to the shaft member of the axial force measuring instrument by the screw member, and the fastened member The axial force generated in the axial direction of the screw member when fastened by the screw member is correlated in advance, and the axial force is measured based on the tightening torque.

According to the thirteenth aspect of the present invention, the same effect as that of the twelfth aspect of the invention can be achieved. The axial force can be measured based on the tightening torque by correlating in advance the tightening torque of the screw member and the axial force generated in the axial direction of the screw member when the member to be fastened is fastened by the screw member. it can.
Therefore, the axial force generated in the axial direction of the screw member can also be measured based on the tightening torque of the screw member when the member to be fastened is fastened by the screw member.

According to the first aspect of the present invention, the shaft member is formed with a groove portion having a detection surface parallel to the direction in which the screw member applies the axial force, and the detection member is provided on the detection surface of the groove portion. Therefore, the detection member can detect the distortion of the shaft member with high sensitivity. And axial force can be calculated | required by performing a predetermined process based on the detected distortion | strain.
Accordingly, the axial force when the fastening member that is actually fixed to the shaft member corresponding to the predetermined shaft is fastened by using the screw member that is actually used can be measured, which is closer to the actual fastening. The axial force in the state can be measured.

According to the second aspect of the present invention, the shaft member is formed with a groove portion having a detection surface parallel to the direction in which the screw member applies the axial force, and the detection member is provided on the detection surface of the groove portion. Therefore, the detection member can detect the distortion of the shaft member with high sensitivity. And axial force can be calculated | required by performing a predetermined process based on the detected distortion | strain. In particular, since the shaft member has the same cross-sectional shape as the surface perpendicular to the axial direction of the predetermined axis, a screw member that is actually used is used as the member to be fastened to the predetermined axis. And can be fastened to the shaft member.
Accordingly, the axial force when the fastening member that is actually fixed to the shaft member corresponding to the predetermined shaft is fastened by using the screw member that is actually used can be measured, which is closer to the actual fastening. The axial force in the state can be measured.

According to the third aspect of the present invention, the shaft member has the load acting surface perpendicular to the direction in which the axial force acts at the position where the screw member acts on the shaft member. Can be made to act in a predetermined direction (for example, a direction toward the axial center of the shaft member).
Therefore, more accurate strain detection based on the axial force can be performed, and more accurate axial force measurement can be performed.

According to the fourth aspect of the present invention, the shaft member has the concave portions that are recessed toward the axial center side of the shaft member from the load acting surface on both end sides in the axial direction of the shaft member of the load acting surface. The acting axial force can be concentrated on the detection member, and the strain accompanying the axial force can be detected with high sensitivity.
Therefore, more accurate strain detection based on the axial force can be performed, and more accurate axial force measurement can be performed.

According to the fifth aspect of the present invention, the groove portion is formed at a position facing each other across the axis of the shaft member, and a detection member is provided on each detection surface of the groove portion. That is, since the detection members provided on the respective detection surfaces are arranged at positions facing each other across the axis of the shaft member, the axial force acting on the shaft member can be detected with high sensitivity.
Therefore, more accurate strain detection based on the axial force can be performed, and more accurate axial force measurement can be performed.

According to the invention described in claim 6, since the shaft member communicates with the groove portions facing each other across the axis of the shaft member and has the through hole perpendicular to the detection surface, the axial force acting on the load acting surface is detected. By concentrating on the member, it is possible to detect the strain accompanying the axial force with high sensitivity.
Therefore, more accurate strain detection based on the axial force can be performed, and more accurate axial force measurement can be performed.

According to invention of Claim 7, since a shaft member is equipped with the detection member which detects the distortion | strain of a shaft member in the surface perpendicular | vertical to the axial direction of the shaft member in a through-hole, a pair with which the detection surface of a groove part is equipped. The detection member and the pair of detection members provided in the through hole are arranged with the angle shifted by 90 degrees.
Therefore, since the strain accompanying the axial force can be detected in different directions, the strain accompanying the axial force can be detected with high sensitivity. Moreover, the detection sensitivity of distortion can be improved by increasing the number of detection members. Therefore, more accurate strain detection based on the axial force can be performed, and more accurate axial force measurement can be performed.

  According to the invention described in claim 8, since the detection member is a strain gauge that detects the compressive strain in the shaft member, the compressive strain in the shaft member can be detected more suitably, and the axial force can be measured more accurately. It can be performed. Moreover, it can be set as a relatively inexpensive axial force measuring instrument.

According to the invention described in claim 9, since the shaft member has a shape set based on the finite element method (FEM), the shape of the shaft member is regarded as a predetermined shaft that actually fixes the fastened member. be able to.
Therefore, since it is possible to measure the axial force when fastening using a screw member that actually uses a fastened member that is actually fixed to a shaft member corresponding to a predetermined shaft, it is closer to actual fastening. The axial force in the state can be measured.

According to the tenth aspect of the present invention, since the shaft member is made of the same material as the predetermined shaft, the shaft member can be regarded as a predetermined shaft that actually fixes the fastened member.
Therefore, since it is possible to measure the axial force when fastening using a screw member that actually uses a fastened member that is actually fixed to a shaft member corresponding to a predetermined shaft, it is closer to actual fastening. The axial force in the state can be measured.

  According to the invention of claim 11, the axial force measuring device includes an axial force measuring instrument, a control unit, and a display unit, and the control unit detects based on the strain detected by the detection member of the axial force measuring instrument. The signal can be processed to determine the axial force. Therefore, the axial force can be easily measured by detecting the strain based on the axial force. Further, since the display unit can display the axial force obtained by the control unit, the measured axial force can be easily recognized and confirmed.

According to the invention described in claim 12, the axial force measuring method is the axial direction of the screw member based on the strain detected by the detecting member when the member to be fastened is fastened to the shaft member of the axial force measuring instrument by the screw member. Can be measured.
Therefore, since it is possible to measure the axial force when fastening using a screw member that actually uses a fastened member that is actually fixed to a shaft member corresponding to a predetermined shaft, it is closer to actual fastening. The axial force in the state can be measured.

According to the thirteenth aspect of the present invention, the axial force measuring method includes the tightening torque of the screw member when the fastened member is fastened to the shaft member of the axial force measuring instrument by the screw member, and the fastened member by the screw member. By correlating in advance the axial force generated in the axial direction of the screw member when fastening, the axial force can be measured based on the tightening torque.
Therefore, the axial force generated in the axial direction of the screw member can also be measured based on the tightening torque of the screw member when the member to be fastened is fastened by the screw member.

Hereinafter, embodiments of the present invention will be described in detail.
The axial force measuring instrument according to the present invention, when fastening a pulley or pinion that is a fastened member fixed to a predetermined shaft with a screw or bolt that is a screw member, generates an axial force generated in the axial direction of the screw member. It is for measuring, and the actual fastening is performed by measuring the axial force when fastening the actual fastening member to the shaft member corresponding to the predetermined shaft using the actual screw member. This is to easily measure the axial force in a state in accordance with the above.

FIG. 1 is a perspective view of an axial force measuring instrument according to the present invention. 2 is a partial cross-sectional perspective view taken along line II-II in FIG. FIG. 3 is a side view of the axial force measuring instrument.
As shown in FIGS. 1 to 3, the axial force measuring instrument 100 includes a shaft member 10 and a strain gauge 20 as a detection member provided in grooves 2 a and 2 b of the shaft member 10 described later.

The shaft member 10 is a shaft-shaped member having the same cross-sectional shape as a surface perpendicular to the axial direction of a predetermined shaft for fixing the member to be fastened, and a flat surface, a groove portion, and the like described later are formed on the shaft-shaped member. The shaft member 10 is formed. The shaft member 10 is formed of the same material as the predetermined shaft.
A surface perpendicular to the direction in which the axial force acts on the shaft member 10 at a position where the screw member acts on the shaft member 10 when the member to be fastened is fastened to the shaft member 10 with the screw member. A load acting surface 1 is formed.
On both ends of the load acting surface 1 in the axial direction of the shaft member 10, recesses 1 a and 1 b that are recessed from the load acting surface 1 toward the axial center of the shaft member 10 are formed.

The load acting surface 1 is a surface for facilitating the application of an axial force to the shaft member 10 in a predetermined direction (direction toward the axial center of the shaft member 10), and the load member 1 is applied to the shaft member 10. It is formed as a reference surface for alignment.
The recesses 1a and 1b are for concentrating the axial force acting on the load acting surface 1 on the strain gauge 20 and detecting the strain accompanying the axial force with high sensitivity.

  Further, the shaft member 10 is formed with groove portions 2a and 2b at positions facing each other across the axis of the shaft member 10. In the groove portions 2a and 2b, when the member to be fastened is fastened to the shaft member 10 by the screw member, the detection surfaces 22a and 22b are surfaces parallel to the direction in which the screw member acts on the shaft member 10. Are formed respectively.

The groove portions 2a and 2b concentrate the axial force acting on the load acting surface 1 on the strain gauge 20, detect the strain accompanying the axial force with high sensitivity, and provide the strain gauge 20 on the shaft member 10. However, it is formed in order to accommodate the shaft member 10 and the fastened member so as not to hinder the fastening.
The detection surfaces 22a and 22b are surfaces formed in order to suitably detect the compressive strain accompanying the axial force that has acted on the load acting surface 1.

  The shaft member 10 is formed with pores 9a and 9b parallel to the axial direction of the shaft member 10 so as to communicate the tip portion 10a of the shaft member 10 and the groove portions 2a and 2b.

  The shape of the shaft member 10 associated with the load acting surface 1, the recesses 1a and 1b, the grooves 2a and 2b, etc. formed on the shaft member 10 is a predetermined value that actually fixes the predetermined member to be fastened. The shape is preliminarily estimated and set by the finite element method (FEM) so that it can be regarded as the axis of the above.

Strain gauges 20 are attached to the detection surfaces 22a and 22b of the grooves 2a and 2b, respectively. A lead wire (not shown) of the strain gauge 20 is inserted through the pores 9a and 9b of the shaft member 10 and extends toward the tip portion 10a.
The strain gauge 20 is a detection member that detects the strain of the shaft member 10. In the present embodiment, as shown in FIGS. 2 and 4, two strain gauges 20 are attached to the detection surfaces 22a and 22b so as to sandwich the partition wall 10b that separates the grooves 2a and 2b in the shaft member 10. It is provided in opposition, and detects the compressive strain in the shaft member 10, especially the compressive strain which acts on the partition part 10b (refer FIG. 4). In order to detect such compressive strain by the strain gauge 20, a circuit such as the circuit diagram shown in FIG.

In addition, in order to detect the compressive strain which acts on the partition part 10b, the structure provided with the strain gauge 20 only in any one of the detection surfaces 22a and 22b may be sufficient. However, if the number of strain gauges 20 is one, when the partition wall portion 10b is bent so as to bend due to an acting force such as an axial force applied to the shaft member 10, the strain gauge 20 has a partition wall portion 10a (detection surface). Since bending bending strain is also detected, there may be a problem that accurate compression strain cannot be detected.
Therefore, if the two strain gauges 20 are provided opposite to each other so as to sandwich the partition wall 10b as in the present embodiment, when the partition wall 10b is bent so as to bend, the one strain gauge 20 is detected. Is detected, and the other strain gauge 20 detects a negative bending strain such that the detection surface contracts. Therefore, each strain gauge 20 detects a strain different from positive and negative. In this case, it is possible to perform error processing on the assumption that the axial force acting on the shaft member 10 does not act in a predetermined direction (a direction perpendicular to the load acting surface 1). Then, each strain gauge 20 is not a positive or negative bending strain, and the compression strain can be detected by detecting the strain when the partition wall portion 10b is compressed in the direction parallel to the detection surface.
That is, as in the present embodiment, the two strain gauges 20 are provided so as to face each other with the partition wall portion 10b interposed therebetween, so that more accurate compression strain can be detected.

Next, an axial force measuring apparatus 1000 that uses the axial force measuring instrument 100 will be described.
FIG. 6 is a block diagram showing an internal configuration of an axial force measuring apparatus 1000 including the axial force measuring instrument 100 according to the present invention.
As shown in FIG. 6, the axial force measuring device 1000 includes an axial force measuring instrument 100, a control unit 30, and a display unit 40. Further, the strain gauge 20, the control unit 30, and the display unit 40 of the axial force measuring instrument 100 are connected by a bus B.

The control unit 30 includes a CPU, a RAM, a ROM, and the like. The CPU of the control unit 30 reads a program stored in the ROM of the control unit 30 and develops the program in the RAM of the control unit 30, and based on the program. Then, instructions to each part constituting the axial force measuring apparatus 1000, transmission / reception of data, and the like are performed.
For example, the control unit 30 performs control to calculate the axial force by processing a detection signal based on the compressive strain detected by the strain gauge 20 of the axial force measuring instrument 100 using a predetermined program.
The predetermined program includes the compressive strain detected by the strain gauge 20 of the axial force measuring instrument 100 when a known load corresponding to the axial force is applied to the shaft member 10 of the axial force measuring instrument 100. The calibration data for which the correlation is previously obtained is stored. Further, as calibration data, the tightening torque when a predetermined fastening member is fastened to the shaft member 10 of the axial force measuring instrument 100 with a predetermined screw member, and the distortion of the axial force measuring instrument 100 at that time The correlation with the compressive strain or axial force detected by the gauge 20 may be obtained in advance.

  The display unit 40 includes, for example, a liquid crystal display mechanism, and displays a detection signal based on the compressive strain detected by the strain gauge 20 of the axial force measuring instrument 100, an axial force obtained by the control unit 30, and the like.

Next, an axial force measuring method using the axial force measuring instrument 100 (axial force measuring device 1000) will be described.
FIG. 7 shows a state where the fastened member 50 is fixed to the shaft member 10 of the axial force measuring instrument 100 in the axial force measuring apparatus 1000 with a set screw 60 as a screw member.
As shown in FIG. 7, the distal end portion 10 a of the shaft member 10 is inserted into the shaft hole 50 a of the fastened member 50, and the fastening hole 50 b of the fastened member 50 is perpendicular to the load acting surface 1 of the shaft member 10. Align so that

  Here, since the cross-sectional shape of the shaft member 10 is the same as the cross-sectional shape of the surface perpendicular to the axial direction of the predetermined shaft that actually fixes the fastened member 50, the shaft member 10 is the fastening hole of the fastened member 50. 50b can fit in the same way as the predetermined axis. Further, the strain gauge 20 is provided in the groove portions 2a and 2b, and the lead wire (not shown) of the strain gauge 20 is inserted through the pores 9a and 9b of the shaft member 10, so that the shaft member 10 is connected to the member to be fastened. When inserted into the 50 fastening holes 50b, the shaft member 10 and the fastened member 50 are not hindered.

Next, the set screw 60 is screwed into the fastening hole 50 b of the fastened member 50, and the fastened member 50 is fastened to the shaft member 10.
When the fastened member 50 is fastened and fixed to the shaft member 10 by the set screw 60, the compression generated in the partition wall portion 10b of the shaft member 10 due to the axial force acting in the axial direction of the set screw 60. The strain gauge 20 detects the strain. Based on the detected compressive strain, the control unit 30 of the axial force measuring apparatus 1000 obtains the axial force and outputs a measurement result such as displaying it on the display unit 40.

As described above, the axial force measuring instrument 100 according to the present invention has the same cross-sectional shape as the plane perpendicular to the axial direction of the predetermined axis for fixing the predetermined fastening member, and the same material as the predetermined axis. Since the shaft member 10 formed by the above is provided, the compressive strain in the case where the actual member to be fastened is fastened to the shaft member 10 corresponding to the predetermined shaft by using the actual screw member (set screw 60). By detecting this, it is possible to detect the compression strain in a state closer to actual fastening, and to measure the axial force in a state closer to actual fastening based on the compression strain.
In particular, the shape of the shaft member 10 is a shape preliminarily estimated and set by a finite element method (FEM) so that the shaft member 10 can be regarded as a predetermined shaft that actually fixes a predetermined fastened member. Therefore, more accurate axial force measurement can be performed.

  Further, in the axial force measuring apparatus 1000 including the axial force measuring instrument 100, the axial force measurement is performed when a known load load corresponding to the axial force is applied to the shaft member 10 of the axial force measuring instrument 100 in a predetermined program. By storing calibration data obtained in advance with a correlation with the compressive strain detected by the strain gauge 20 of the instrument 100, the axial force can be calculated based on the compressive strain detected by the strain gauge 20. Further, in a predetermined program, a tightening torque for fastening a predetermined member to be fastened to the shaft member 10 of the axial force measuring instrument 100 with a predetermined screw member (set screw 60), and the axial force measuring instrument at that time The axial force can be calculated based on the tightening torque by storing calibration data obtained in advance in correlation with the compressive strain and axial force detected by the 100 strain gauges 20.

  In addition, various shaft members with different shaft diameters, shaft cross-sectional shapes, materials constituting the shaft, etc. are formed according to various members to be fastened and predetermined shafts to which the members to be fastened are fixed. By preparing the measuring instrument, it is possible to easily perform axial force measurement according to various fastened members and predetermined axes.

  Therefore, the axial force measuring instrument, the axial force measuring device, and the axial force measuring method according to the present invention use a screw member that actually uses a fastened member to be actually fixed to a shaft member corresponding to a predetermined shaft. It can be said that the axial force measuring instrument, the axial force measuring device, and the axial force measuring method are capable of measuring the axial force in a state in accordance with the actual fastening.

  The application of the present invention is not limited to the above-described embodiment, and can be appropriately changed without departing from the spirit of the present invention.

For example, the shaft member 11 shown in FIGS. 8A and 8B may be the shaft member in the axial force measuring instrument.
In the shaft member 11, grooves 3a and 3b are formed at positions facing each other across the axis of the shaft member 11, respectively. In the grooves 3a and 3b, when the member to be fastened is fastened to the shaft member 11 with a screw member, the detection surfaces 33a and 33b are surfaces parallel to the direction in which the screw member acts on the shaft member 10. Are formed respectively.
The groove portions 3a and 3b are formed so that the strain gauge 20 provided in the shaft member 11 is accommodated so as not to hinder the fastening between the shaft member 11 and the fastened member.
The shaft member 11 has the same cross-sectional shape as a surface perpendicular to the axial direction of a predetermined shaft that fixes the member to be fastened, and is formed of the same material as the predetermined shaft.
Moreover, the groove parts 3a and 3b have a shape determined based on the finite element method.

  Even in the axial force measuring instrument including the shaft member 11 having such a shape, an actual fastening member is fastened to the shaft member 11 corresponding to a predetermined shaft by using an actual screw member (set screw 60). By detecting the compressive strain, it is possible to detect the compressive strain in a state closer to the actual fastening, and to measure the axial force in a state closer to the actual fastening based on the compressive strain Can do.

Further, for example, the shaft member in the axial force measuring instrument may be the shaft member 12 shown in FIG.
The shaft member 12 communicates with the groove portions 2a and 2b in the shaft member 10 and is formed with a through hole 4 perpendicular to the detection surfaces 22a and 22b.
The through hole 4 is for concentrating the axial force acting on the load acting surface 1 on the strain gauge 20 and detecting the strain accompanying the axial force with high sensitivity.
The shaft member 12 has the same cross-sectional shape as the surface perpendicular to the axial direction of the predetermined shaft that fixes the member to be fastened, and is formed of the same material as the predetermined shaft.
The through hole 4 has a shape determined based on the finite element method.

  Even in the axial force measuring instrument including the shaft member 12 having such a shape, an actual fastening member is fastened to the shaft member 12 corresponding to a predetermined shaft by using an actual screw member (set screw 60). By detecting the compressive strain, the compression strain in the state closer to the actual fastening can be detected, and the axial force in the state closer to the actual fastening is measured based on the compression strain. Can do.

Further, as shown in FIG. 10, a strain gauge 20 that detects strain of the shaft member 12 may be provided on a surface perpendicular to the axial direction of the shaft member 12 in the through hole 4 of the shaft member 12.
As described above, the strain gauge pairs in which the two strain gauges 20 face each other are arranged with the angle shifted by 90 degrees, and the number of the strain gauges 20 is increased, so that the detection sensitivity of the compressive strain can be improved.

The shape of the shaft member is not limited to the above-described embodiment, and may be other shapes and sizes such as a circular cross section and the size of the shaft diameter.
Further, the shape of the groove portion or the like of the shaft member is not limited to the above-described embodiment, and may be another shape.
Moreover, the number of the strain gauges 20 and the sticking position are also arbitrary.

  In addition, it is needless to say that other specific detailed structures can be appropriately changed.

It is a perspective view of the axial force measuring instrument according to the present invention. It is a partial cross section perspective view in the II-II line of FIG. It is a side view of the axial force measuring instrument which concerns on this invention. It is explanatory drawing which shows arrangement | positioning of a strain gauge. It is a circuit diagram regarding a strain gauge. It is a block diagram which shows the principal part structure of the axial force measuring apparatus which concerns on this invention. It is explanatory drawing which shows the state which fixed the to-be-fastened member to the shaft member with the set screw. It is the perspective view (a) which shows the modification of a shaft member, and the partial cross section perspective view (b) in the bb line of (a). It is a perspective view which shows the modification of a shaft member. It is explanatory drawing which shows the example of arrangement | positioning of a strain gauge. It is explanatory drawing which shows the state which fastened the to-be-fastened member to the target object with the volt | bolt. It is a side view which shows the volt | bolt for axial force measurement as a prior art. It is sectional drawing which shows the volt | bolt for axial force measurement as a prior art. It is explanatory drawing which shows the axial force measuring method as a prior art. It is explanatory drawing (a) which shows the axial force measuring method as a prior art, and a perspective view (b) of a load washer. It is explanatory drawing which shows the state which fastened the to-be-fastened member to the target object with the set screw.

Explanation of symbols

1000 Axial force measuring device 100 Axial force measuring instrument 10, 11, 12 Shaft member 1 Load acting surface 1a, 1b Recess 2a, 2b Groove 22a, 22b Detection surface 3a, 3b Groove 33a, 33b Detection surface 4 Through hole 20 Strain gauge ( Detection member)
30 Control part 40 Display part 50 Fastened member 60 Set screw (screw member)

Claims (13)

An axial force measuring instrument for measuring an axial force generated in the axial direction of the screw member when the member to be fastened is fastened to the predetermined shaft by the screw member,
A shaft member in which a groove portion having a detection surface parallel to a direction in which the screw member acts an axial force when the fastened member is fastened by the screw member;
A detection member that is provided on a detection surface of the groove and detects strain of the shaft member;
An axial force measuring instrument comprising: An axial force measuring instrument for measuring an axial force generated in the axial direction of the screw member when the member to be fastened is fastened to the predetermined shaft by the screw member,
A detection surface that has the same cross-sectional shape as a surface perpendicular to the axial direction of the predetermined axis and that is parallel to the direction in which the screw member acts an axial force when the member to be fastened is fastened by the screw member. A shaft member formed with a groove having,
A detection member that is provided on a detection surface of the groove and detects strain of the shaft member;
An axial force measuring instrument comprising:   The axial force measuring instrument according to claim 1, wherein the screw member has a load acting surface perpendicular to a direction in which the axial force acts at a position where the screw member acts on the shaft member.   4. The recess according to claim 1, wherein the load acting surface has concave portions that are recessed toward the axial center side of the shaft member from the load acting surface at both ends in the axial direction of the shaft member. The axial force measuring instrument as described.   The groove portion is formed at a position facing each other across the axis of the shaft member, and the detection member is provided on each detection surface of the groove portion. The axial force measuring instrument according to one item.   The axial force measuring instrument according to claim 5, further comprising a through hole that communicates with a groove portion opposed across the axis of the shaft member and is perpendicular to the detection surface.   The axial force measuring instrument according to claim 6, further comprising: a detection member that detects a strain of the shaft member on a surface perpendicular to the axial direction of the shaft member in the through hole.   The axial force measuring instrument according to claim 1, wherein the detection member is a strain gauge that detects compressive strain in the shaft member.   The axial force measuring instrument according to any one of claims 1 to 8, wherein the shaft member has a shape set based on a finite element method.   The axial force measuring instrument according to any one of claims 1 to 9, wherein the shaft member is formed of the same material as the predetermined shaft. The axial force measuring instrument according to any one of claims 1 to 10,
A control unit that processes a detection signal based on the strain detected by the detection member of the axial force measuring instrument and performs control to obtain axial force;
A display unit for displaying the axial force obtained by the control unit;
An axial force measuring device comprising:   When the member to be fastened is fastened to the shaft member of the axial force measuring instrument according to any one of claims 1 to 10 by a screw member, the axial direction of the screw member is based on the strain detected by the detection member. A method of measuring an axial force, characterized by measuring an axial force generated.   The tightening torque of the screw member when the fastened member is fastened to the shaft member of the axial force measuring instrument by the screw member, and the axial force generated in the axial direction of the screw member when the fastened member is fastened by the screw member Are measured in advance, and the axial force is measured based on the tightening torque.

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