JP2010125563A - Axial force-detecting fastening tool - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make an ultrasonic sensor accurately abut on the tip of a bolt. <P>SOLUTION: The axial force-detecting fastening tool includes: a socket body 5 capable of fastening by rotation around an axis given from rotational drive force of an electric motor; an inner socket-supporting tube 16 at a tool body 3 side; an inner socket 7 having a concave portion 35 at the tip-side inner peripheral surface that fits and supports a pin-tail 83 of a bolt 75, and locks turning with respect to the tool body 3; a sensor spring 45; and the ultrasonic sensor 11 which uses outputting/inputting ultrasonic waves for detecting the axial force of the bolt 75. The inner socket 7 has a spherical receiving part 63 biased by a spherical biasing spring 61. The ultrasonic sensor 11 has a spherical contact part 65 that contacts with the spherical receiving part 63 and supports the inner socket 7 spherically. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to an axial force detection fastening tool used for fastening bolts and nuts such as automobile suspensions.

  An example of a conventional axial force detection fastening tool is shown in FIG.

  The fastening tool shown in FIG. 5 has a measuring socket 201 detachably attached to a torque wrench 203. The measurement socket 201 includes a socket body 205 and a stationary member 207. The socket body 105 is rotatable relative to the stationary member 107. The socket body 205 is provided with a bolt fitting hole 209. The bolt fitting hole 209 is configured to be fitted to the head portion 212 of the bolt 211. An ultrasonic sensor 213 is accommodated in the back side of the bolt fitting hole 209.

  The ultrasonic sensor 213 is obtained by attaching a piezoelectric element 115 to a main body 214 formed of a permanent magnet. The piezoelectric element 215 is configured to directly contact the bolt head 212. A lead wire 217 is connected to the piezoelectric element 215, and the lead wire 217 is connected to one terminal of the slip ring 219. A coaxial cable 221 supported by the stationary member 207 is connected to the other terminal of the slip ring 219.

  The torque wrench 203 is configured such that the drive shaft 223 and the ratchet mechanism 225 are rotationally interlocked by meshing of the bevel gears 227 and 229. A shaft portion 231 that interlocks with the ratchet mechanism 225 is fitted to the upper end of the socket body 205 and is coupled by a pin 233.

  When fastening the bolt, when the bolt fitting hole 209 of the socket body 205 is fitted to the head portion 212 of the bolt 211, the head portion 212 is attracted to the permanent magnet body 214 and the piezoelectric element 215 is brought into contact with the top surface of the head 212. Can be made.

  Next, when the drive shaft 223 is rotationally driven, the shaft portion 231 is rotationally driven via the bevel gears 227 and 229 and the ratchet mechanism 225. The socket body 205 is interlocked by the rotation of the shaft portion 231 and rotates relative to the stationary member 207. Due to the rotation of the socket body 205, the head portion 212 of the bolt 211 receives a rotational force, the bolt 211 is tightened with respect to the block 235, and the fastened object 237 is fastened.

  At this time, the fastening force by the bolt 211 is performed by managing the axial force of the bolt 211. That is, when an ultrasonic wave is transmitted from the piezoelectric element 215 under the control of the controller, the piezoelectric element 215 receives the reflected wave reflected by the tip of the bolt 211. The controller obtains the elapsed time from the time when the ultrasonic wave is transmitted to the time when the reflected wave is received as the reciprocal time required for the ultrasonic wave to reciprocate the bolt 211 in the axial length direction. From this, the axial length of the bolt 111 is obtained. Then, the elongation rate of the axial length of the bolt 211 associated with the tightening is obtained, the axial force value proportional to the elongation rate is obtained, and when the axial force value becomes a set value, the bolt 211 is fastened. Can be completed. Therefore, accurate fastening according to the axial force of the bolt 211 can be performed.

  However, in the above structure, it can be used when the bolt 211 is directly fastened to the block 135 or the like. However, in the operation of tightening the nut to the bolt 211, the bolt 211 is fitted even if the socket body 205 is fitted to the nut and tightened. , And it becomes impossible to perform the work of tightening the nut while holding the axial force detection fastening tool with one hand and measuring the axial force.

  In the operation of tightening the nut into the bolt 211, it is possible to tighten the nut without causing rotation of the bolt when the bolt is, for example, an implanted bolt. However, in this case, the bolt tip and the piezoelectric element 215 rotate relative to each other in the process of tightening the nut, and the piezoelectric element 215 is easily damaged, and it is not possible to tighten the nut while measuring the bolt axial force. As a result, it was difficult.

  Further, when the nut is tightened into the bolt, the bolt tip protrudes with respect to the nut according to the tightening. Therefore, in the case where the ultrasonic sensor 213 is fixedly provided on the socket body 205 as shown in FIG. Cannot cope with the protrusion to the ultrasonic sensor 213 side.

  Further, since the piezoelectric element 215 is fixedly attached to the main body 214 formed of a permanent magnet, the surface where the main body 214 abuts on the head 212 of the bolt 211 and the piezoelectric element 215 abuts on the head 212 of the bolt 211. If the surfaces are not accurately aligned, the main body 214 will contact the head 212 accurately, but the piezoelectric element 215 may not be able to accurately contact, and the assembly of the main body 214 and the piezoelectric element 215 is extremely complicated. And it can be difficult.

  In addition, since the ultrasonic sensor 213 is fixedly attached to the socket body 205, signal transmission between the piezoelectric element 215 and the controller side must be performed between the socket body 205 and the stationary member 207 that rotate relative to each other. A structure in which the lead wire 217 and the coaxial cable 221 are connected by the slip ring 219 has a problem that the structure is complicated and durability at the slip ring 219 is low.

  In addition, since the stationary member 207 exists between the socket body 205 and the torque wrench 203, for example, in the vehicle assembly process, tightening of the nut in the recessed portion such as fastening of the suspension slat and the knuckle arm is performed. When the socket body 205 is inserted, even if it tries to insert the socket main body 205 into the recessed part, it cannot be inserted so much due to the presence of the stationary member 207, and there is a possibility that the operation becomes difficult or is limited.

  On the other hand, a pin / tail is formed on the outer periphery of the bolt's tip as an engaging part in the rotational direction along the axial direction by serration, etc., and the axial force that can tighten the nut on this bolt while detecting the axial force of the bolt The present applicant has already proposed a detection fastening tool.

  In this axial force detection fastening tool, an ultrasonic sensor is brought into contact with the tip of the bolt by accurately fitting a support portion of the inner socket of the tool to a pin tail that is an engaging portion of the bolt. In this state, the bolt is locked to the tool side via the inner socket. A nut that is screwed to the bolt and fitted into a nut fitting portion provided in the socket body of the tool is fastened to the bolt by rotation of the socket body that is driven to rotate by an electric motor. At this time, the ultrasonic wave output from the ultrasonic sensor in contact with the tip of the bolt is reflected by the surface of the bolt head and input to the ultrasonic sensor, so that the axial force of the bolt can be detected.

  In such an axial force detection fastening tool, there is a problem of accurately bringing the ultrasonic sensor into contact with the tip of the bolt.

JP 2000-74764 A JP 2005-279920 A

  The problem to be solved is that in the axial force detection fastening tool that measures the bolt axial force while fastening the nut to the bolt, it is important to accurately contact the ultrasonic sensor with the tip of the bolt. .

  The present invention relates to an axial force that tightens a nut while detecting an axial force on a bolt having an engaging portion in a rotational direction along the axial direction on the outer periphery of the tip in order to make an ultrasonic sensor accurately contact the tip of the bolt. A detection fastening tool comprising a nut fitting portion for fitting the nut and rotatably supported by the tool body, and the nut fitted to the nut fitting portion is prevented from rotating with respect to the tool body. A socket body that can be fastened to the bolt by rotating around the axis by a rotational drive output of a rotary actuator, a support portion on the tool body side that is concentrically formed with respect to the socket body, and a concentric shape with the socket body and the support portion The tool book is disposed so as to face the nut fitting portion so that it cannot rotate with respect to the support portion and is removably moved from the nut fitting portion so that the engagement portion of the bolt is fitted and supported. An inner socket provided with an engaging portion that stops and locks against the inner periphery of the tip end, and an urging member that urges the inner socket toward the support portion and faces the nut fitting portion side An ultrasonic sensor for detecting the axial force of the bolt, which is supported by the axial center portion of the inner socket along the axial direction and is input to and output from the front end of the bolt on the locking portion side The most important feature is that the support of the ultrasonic sensor with respect to the inner socket can be tilted in accordance with the inclined insertion of the front end of the engagement portion of the bolt.

  An axial force detection fastening tool according to the present invention is an axial force detection fastening tool for tightening a nut while detecting axial force on a bolt provided with an engaging portion in a rotational direction along the axial direction on the outer periphery of the tip. According to the rotational drive output of the rotary actuator, the nut fitted with the nut fitting portion to be fitted is rotatably supported by the tool body and the nut fitted to the nut fitting portion is prevented from rotating with respect to the tool body. A socket body that can be tightened by rotating around an axis, a support portion on the side of the tool body that is concentrically formed with respect to the socket body, and the socket body and the support portion that are concentrically disposed in the nut fitting portion. A support portion that is axially movable and supported so as to be non-rotatable relative to the support portion and retract from the inside of the nut fitting portion, and to engage and support the engagement portion of the bolt and to prevent rotation with respect to the tool body. An inner socket provided on the inner periphery of the end side, a biasing member that biases the inner socket against the support portion and faces the nut fitting portion side, and a shaft on the shaft center portion of the inner socket An ultrasonic sensor that is used to detect the axial force of the bolt that is supported along the center direction and that is input to and output from the front end of the bolt on the locking portion side. The support for the socket can be tilted according to the tilt insertion at the tip of the bolt on the engaging portion side.

  For this reason, when the nut is tightened with respect to the bolt by the rotation of the socket body about the axis, the ultrasonic sensor and the bolt do not rotate relative to each other, and the damage of the ultrasonic sensor can be suppressed and the durability can be improved.

  The ultrasonic sensor can be brought into elastic contact with the tip of the bolt accurately by the urging force of the urging member, and can accurately detect the axial force.

  When tightening the nut, even if the tip of the bolt protrudes relatively to the ultrasonic sensor side with respect to the nut, the ultrasonic sensor can move back toward the tool body against the biasing force of the biasing member. The nut can be tightened with ease on the bolt while detecting the force.

  Since the ultrasonic sensor is supported on the tool body side, wiring can be performed directly from the tool body side to the ultrasonic sensor without using a slip ring, and durability can be improved. it can.

  Since no other stationary member is interposed between the tool body side and the socket body side, the socket body tip side can be obtained by holding the tool body even when the nut is located in a deep part of a narrow space. Can be inserted into a narrow portion, and a nut can be fitted into the nut fitting portion to easily perform the fastening operation and the axial force detection, and the workability can be greatly improved.

  In addition, the ultrasonic sensor can be tilted with respect to the inner socket according to the inclination of the front end of the engagement portion side of the bolt even if the engagement portion of the bolt is inclined and inserted with respect to the locking portion of the inner socket. The ultrasonic sensor can be accurately brought into contact with the front end of the bolt on the engagement portion side.

  By this accurate contact, the nut can be fastened while preventing the bolt from rotating, and the fastening can be completed while detecting the axial force by the ultrasonic sensor.

  An axial force detection fastening tool that measures bolt axial force while fastening a nut to a bolt. The ultrasonic sensor can be tilted with respect to the inner socket for the purpose of accurately contacting the ultrasonic sensor to the tip of the bolt. Realized by support.

  1 is a partially omitted cross-sectional view showing an axial force detection fastening tool according to a first embodiment of the present invention in a state of fastening, FIG. 2 is an enlarged cross-sectional view of the main part, and FIG. 3 is an axial force detection fastening tool. It is a partially abbreviated sectional view showing the state in a non-fastened state.

  As shown in FIGS. 1 to 3, the axial force detection fastening tool 1 includes a tool body 3, a socket body 5, an inner socket 7, a drive transmission mechanism 9 that transmits the rotation of an electric motor that is a rotary actuator, It consists of an ultrasonic sensor 11.

  The tool body 3 is formed by integrally forming a hollow lever portion 13 and a hollow lever head 15. The lever portion 13 is formed in a hollow shape so that an operator can hold it with one hand. The electric motor is attached to an end of the lever portion 13 that is not shown.

  The lever head 15 has an axial center orthogonal to the axial center of the lever portion 13, and an inner socket support cylinder 16 is concentrically fixed to the axial center portion as a support portion on the tool body 3 side. ing.

  The lever head 15 is provided with a support tube mounting hole 14. A keyway 20 is provided in the support tube mounting hole 14.

  The inner socket support tube 16 is provided with a male screw portion 24 and a key groove 26 at the mounting end 22. The mounting end 22 is inserted into the support tube mounting hole 14 of the lever head 15 and is fixed by a nut 28, and is prevented from rotating by a key 60 fitted in the key grooves 20 and 26.

  An inner spline 17 is provided along the axial direction on the inner periphery of the distal end side of the inner socket support tube 16. A spring support hole 18 is provided on the inner side of the inner socket support tube 16. The spring support hole 18 communicates with the outside of the attachment end 22 through the through hole 30.

  The socket body 5 is rotatably supported by the lever head 15 of the tool body 3. The socket body 5 includes a rotation interlocking part 34 and a nut driving part 36.

  The rotation interlocking part 34 is provided with an engagement hole 38. The engagement hole 38 is constituted by, for example, a hexagonal hole in cross section. The nut driving portion 36 is provided with an engaging end portion 40. The engagement end 40 is formed in a hexagonal cross section corresponding to the engagement hole 38. An engagement flange 42 is provided on the nut driving portion 36 adjacent to the engagement end portion. The engagement end portion 40 of the nut driving portion 36 is fitted into the engagement hole 38 of the rotation interlocking portion 34, and the engagement flange 42 receives a fastening force by the nut member 44 screwed to the rotation interlocking portion 34. A nut driving unit 36 is fastened and coupled to the rotation interlocking unit 34 so as not to be relatively rotatable.

  A nut fitting portion 19 for fitting with the nut 55 is formed at an end portion of the nut driving portion 36. The nut fitting part 19 is formed in a hexagonal cross section so that it can be fitted corresponding to, for example, a hexagonal nut. An inner socket insertion hole 23 having a circular cross section is provided in the flange wall 21 of the nut fitting portion 19, and a fitting shaft hole 25 communicating with the inner socket insertion hole 23 is provided adjacent to the inner wall 21. It has been. The fitting shaft hole 25 is fitted to the outer periphery of the inner socket support tube 16, and the nut driving portion 36 is rotatable relative to the inner socket support tube 16.

  The rotation interlocking portion 34 has a fitting shaft hole 48 having the same diameter as the fitting shaft hole 25 of the nut driving portion 36, and the fitting shaft hole 48 is fitted around the outer periphery of the inner socket support tube 16. In addition, the rotation interlocking portion 34 is rotatable relative to the inner socket support tube 16. The rotation interlocking portion 34 is rotatably supported by a bearing 31 on a cap 27 whose outer peripheral side is screwed into the lever head 15. The inner peripheral side of the rotation interlocking portion 34 is rotatably supported by the needle bearing 33 on the attachment end 22 side of the inner socket support tube 16. A rotation bevel gear 29 is provided at the end of the rotation interlocking portion 34 on the base side.

  The inner socket 7 is formed in a circular cross section, is concentrically disposed in the socket main body 5 and the inner socket support cylinder 16, is non-rotatable with respect to the inner socket support cylinder 16 on the tool main body 3 side, and has a shaft. The inner serration 37 is provided as a locking portion that locks the engagement portion for locking the bolt tip. That is, the inner socket 7 is provided with a concave portion 35 that constitutes the locking portion at the tip. Inner serrations 37 are provided on the inner peripheral surface of the recess 35, and chamfers 35 a and 35 b that facilitate the insertion of pin tails are provided in two stages at the opening end of the recess 35.

  A sensor insertion hole 39 is formed through the shaft portion of the inner socket 7. The inner socket 7 faces into the nut fitting part 19 from the inner socket insertion hole 23, and its tip projects out of the nut fitting part 19 in an unfastened state (FIG. 3). A spline 41 is provided at the base end of the inner socket 7. The spline 41 is spline-fitted to the inner spline 17 of the inner socket support tube 16. By this spline fitting, the inner socket 7 is supported to be movable in the axial direction so as not to rotate with respect to the inner socket supporting cylinder 16 and to move away from the nut fitting portion 19.

  The ultrasonic sensor 11 is inserted into the sensor insertion hole 39 in the axial center portion of the inner socket 7 and is movable and supported in a certain range in the axial direction. The tip of the ultrasonic sensor 11 faces the recess 35 of the inner socket 7. The ultrasonic sensor 11 inputs and outputs ultrasonic waves in contact with the bolt tip, and is used for detecting the axial force of the bolt.

  A screw hole 52 is provided in the base end face of the inner socket 7, and a through hole 7 a is provided in an intermediate portion in the axial direction. A spring seat 54 is screwed into the screw hole 52 of the inner socket 7.

  A sensor spring 45 is interposed as a biasing member between the spring seat 54 and the spring support hole 18 of the inner socket support cylinder 16.

  The inner socket 7 is urged against the inner socket support tube 16 by the sensor spring 45, and this inner socket 7 is made to face the nut fitting portion 19 side. Further, the ultrasonic sensor 11 is biased toward the nut fitting portion 19 by the sensor spring 45 through the inner socket 7.

  The ultrasonic sensor 11 can be tilted with respect to the inner socket 7 by spherical support.

  That is, the inner socket 7 is provided with a spherical receiving portion 63 biased by a spherical biasing spring 61 which is a spherical biasing member. The spherical surface receiving portion 63 is formed in a ring shape and includes a concave spherical surface 63a, and the outer peripheral surface is supported by the inner peripheral surface of the inner socket 7 so as to be slidable in the axial direction. The spherical biasing spring 61 is interposed between the spherical receiving portion 63 and the spring seat 54. The spring constant of the spherical biasing spring 61 is set smaller than the spring constant of the sensor spring 45.

  The ultrasonic sensor 11 is provided with a male screw portion 11a, and a spherical contact portion 65 is screwed and fixed. The spherical contact portion 65 is provided with a convex spherical surface 65a. The convex spherical surface 65 a is formed with the same curvature as that of the concave spherical surface 63 a of the spherical surface receiving portion 63, abuts against the concave spherical surface 63 a, and provides spherical support to the inner socket 7 of the ultrasonic sensor 11. The center of curvature of the convex spherical surface 65 a is the center of the tip surface of the ultrasonic sensor 11. The center of the front end surface of the ultrasonic sensor 11 is the center of a later-described front end side reference surface of the bolt with which the ultrasonic sensor 11 correctly contacts.

  Note that the center of curvature of the convex spherical surface 65 a can be set to be shifted in any axial direction from the center of the tip surface of the ultrasonic sensor 11.

  A lock nut 67 is fastened to the distal end side of the ultrasonic sensor 11.

  A lead wire 46, which is the wiring of the ultrasonic sensor 11, passes through the inside of the sensor spring 45 and extends toward the spring support hole 18, and a grommet 54 attached to the through hole 30 from the spring support hole 18. It penetrates and is pulled out of the lever head 15 and connected to a controller (not shown) for calculating the axial force. The lead wire 46 is supported on the outer surface of the lever portion 13 by a fixed band 56 at a plurality of locations.

  The drive transmission mechanism 9 includes a drive shaft 47 and a bevel gear mechanism 49. The drive shaft 47 is disposed along the lever portion 13 of the tool body 3 and is rotatably supported by the lever portion 13 by a needle bearing 58 or the like. The drive shaft 47 is configured to be rotationally driven by the electric motor.

  The bevel gear mechanism 49 is provided between the drive shaft 47 and the socket body 5 and transmits the rotation of the drive shaft 47 to the socket body 5 by meshing. The bevel gear mechanism 49 includes a bevel gear 29 of the socket body 5 and a bevel gear 51 provided at an end of the drive shaft 47, and the bevel gears 29 and 51 are engaged with each other.

The axial force detection fastening tool 1 unfastens the nut 28 and unscrews the cap 27 from the lever head 15, thereby removing the inner socket support tube 16, the socket body 5, and the inner socket 7. It can be attached and detached as a unit. Therefore, repair, inspection, replacement, etc. of the socket body 5 and the inner socket 7 can be easily performed.
[Fastening operation]
FIG. 4 is an enlarged cross-sectional view of the main part showing the tilting of the ultrasonic sensor during the fastening operation.

  In the fastening operation, for example, the fastening object 77 such as the boss part of the suspension strut and the knuckle arm is fastened by the bolt 75 and the nut 55.

  As shown in FIGS. 1, 2, and 4, the bolt 75 has a head 79 at one end, and the head 79 is provided with a flat head-side reference surface 80 orthogonal to the axis. A pin tail 83 formed by serration is provided at the tip of the male screw portion 81 as an engaging portion for preventing rotation. A flat tip side reference surface 85 orthogonal to the axis is formed at the tip of the bolt 75. A chamfer 75 a that facilitates insertion into the recess 35 is provided on the outer periphery of the front end of the bolt 75. The nut 55 is screwed into the male screw portion 81 in advance.

(Normal insertion)
In order to fasten the nut 55 to the bolt 75, the fastener 1 is mounted on the bolt 75, and the concave portion 35 of the inner socket 7 is inserted into the pin tail 83 and serrated. At this time, the chamfer 75a on the bolt 75 side and the chamfers 35a and 35b on the concave 3 side can surely and easily insert the concave portion 35 into the pin tail 83.

  By this insertion, the tip of the ultrasonic sensor 11 is pressed against the tip side reference surface 85 of the bolt 75.

  When the ultrasonic sensor 11 receives a pressing force, the spherical biasing spring 61 is bent through the lock nut 67, the spherical contact portion 65 and the spherical receiving portion 63. By this spherical biasing spring 61, the convex spherical surface 65a of the spherical abutting portion 65 closely contacts the concave spherical surface 63a of the spherical surface receiving portion 63.

  When the spherical biasing spring 61 is bent and bottomed, the sensor spring 45 that receives a force via the inner socket 7 is bent, and the inner socket 7 is biased by the sensor spring 45 against the nut fitting portion 19. Retreat against it.

  Accordingly, the spline 41 of the inner socket 7 moves along the inner spline 17 of the inner socket support cylinder 16, and the inner socket 7 moves away from the nut fitting portion 19.

  By this retreating movement, the nut 55 is fitted into the nut fitting portion 19 as shown in FIG.

  At this time, since the biasing force of the sensor spring 45 also acts on the ultrasonic sensor 11 via the inner socket 7, it is possible to accurately bring the tip of the ultrasonic sensor 11 into contact with the tip-side reference surface 85 of the bolt 75. it can.

  When the fastener 1 is detached from the bolt 75, the inner socket 7 is moved to the nut fitting portion 19 side by the biasing force of the sensor spring 45, and the ultrasonic sensor 11 is restored by the biasing force of the spherical biasing spring 61. Move axially to position. At this time, the inner socket 7 engages with the outer surface of the edge of the inner socket insertion hole 23 and is positioned as shown in FIG. 3, and the lock nut 67 side engages with the edge of the recess 35 to Is positioned as follows.

(Inclined insertion)
When the fastener 1 is displaced with respect to the bolt 75 and the recess 35 is inserted into the pin tail 83 in an inclined state, the tip of the bolt 75 contacts the tip of the ultrasonic sensor 11 in an inclined state.

  At this time, the tip of the ultrasonic sensor 11 receives a pressing force from the tip-side reference surface 85 of the bolt 75, and the convex spherical surface 65 a of the spherical contact portion 65 has a radius of curvature R with respect to the concave spherical surface 63 a of the spherical receiving portion 63. As shown in FIG. 4, the bolt 75 rotates relative to the center of the front end side reference surface of the bolt 75, and rotates by θ ° in accordance with the inclination of the bolt 75.

  By this tilt rotation, the tip of the ultrasonic sensor 11 can be brought into contact with the tip side reference surface 85 of the bolt 75 accurately.

(Conclusion)
In the normal insertion or the inclined insertion, when the drive shaft 47 is rotationally driven by the drive of the electric motor, the socket body 5 is rotationally driven through the bevel gears 51 and 29 by the rotational drive. At this time, since the inner socket 7 is supported by the inner socket support tube 16 on the tool body 3 side so as not to rotate, the inner socket 7 is stationary, and only the socket body 5 rotates around the inner socket 7.

  Due to the rotation of the socket body 5, the nut 55 is rotated through the nut fitting portion 19 and fastened to the bolt 75. At this time, the bolt 75 is prevented from rotating with respect to the tool body 3 side by the serration engagement of the pin tail 83 with the recess 35 of the inner socket 7. Accordingly, the nut 55 can be securely tightened while the rotation of the socket main body 5 is performed, while the bolt 75 is prevented from rotating.

  The ultrasonic wave transmitted from the ultrasonic sensor 11 is reflected by the head side reference surface 80 of the head 79 of the bolt 75, and the reflected wave is received by the ultrasonic sensor 11. By transmitting and receiving this ultrasonic wave, the controller needs the elapsed time from the time when the ultrasonic wave is transmitted to the time when the reflected wave is received so that the ultrasonic wave can reciprocate the bolt 75 in the axial length direction. The reciprocation time is obtained, and the axial center length of the bolt 75 is obtained from the reciprocation time.

Then, the elongation rate of the axial center length of the bolt 75 associated with the tightening of the nut 55 is obtained, and the axial force value proportional to the elongation rate is obtained and output to a display or the like. The operator views the axial force value displayed on the display, and stops the rotation of the electric motor when the displayed axial force value reaches a set value. Alternatively, the electric motor is automatically stopped at a preset axial force value under the control of the controller. By this stop, the fastening by the bolt 75 and the nut 55 of the fastening object 77 such as the fastening between the boss portion of the suspension strut and the knuckle arm can be accurately performed by the set axial force.
[Effect of Example]
The axial force detection fastening tool 1 according to the embodiment of the present invention is an axial force detection that tightens a nut 55 while detecting an axial force on a bolt 75 having a pin tail 83 that is an engaging portion in the rotational direction along the axial direction on the outer periphery of the tip. The fastening tool 1 includes a nut fitting portion 19 for fitting the nut 55 and is rotatably supported by the tool main body 3 and fitted to the nut fitting portion 19 with respect to the tool main body 3. A socket body 5 that can be fastened to the bolt 75 that is prevented from rotating by rotating around the axis by the rotational drive output of the electric motor, and an inner socket support on the tool body 3 side that is concentrically formed with respect to the socket body 5 The cylinder 16 is disposed concentrically with the socket body 5 and the inner socket support cylinder 16 so as to face the nut fitting portion 19 and be unrotatable with respect to the inner socket support cylinder 16. A recess 35 is provided on the inner periphery on the front end side so as to be removably moved from the inside of the fitting fitting portion 19 and is supported in the axial direction so as to be fitted and supported by the pin tail 83 of the bolt 55 and locked to the tool body 3. An inner socket 7, a sensor spring 45 that urges the inner socket 7 against the inner socket support tube 16 and faces the nut fitting portion 19, and an axis of the inner socket 7. An ultrasonic sensor 11 for detecting the axial force of the bolt 75 by using the ultrasonic wave which is supported by the portion along the axial direction and is input to the tip of the bolt 75 while being in contact with the tip of the bolt 75 on the inner socket support cylinder 16 side. The ultrasonic sensor 11 can be supported by the inner socket 7 in accordance with the insertion of the bolt 55 at the tip end on the pin tail 83 side.

  For this reason, when the nut 55 is tightened with respect to the bolt 75 by the rotation of the socket body 5 around the axis, the ultrasonic sensor 11 and the bolt 75 do not rotate relative to each other, and the damage of the ultrasonic sensor 11 is suppressed and the durability is improved. Can be made.

  The ultrasonic sensor 11 can be elastically contacted with the front end side reference surface 85 of the bolt 75 by the urging force of the sensor spring 45, and can perform accurate axial force detection.

  When the nut 55 is tightened, even if the tip of the bolt 75 protrudes relative to the nut 55 toward the ultrasonic sensor 11, the ultrasonic sensor 11 moves toward the tool body 3 against the urging force of the sensor spring 45. The nut 55 can be retracted and the nut 55 can be tightened with ease against the bolt 75 while detecting the axial force.

  Since the ultrasonic sensor 11 is supported on the tool body 3 side, wiring can be performed directly from the tool body 3 side to the ultrasonic sensor 11 without using a slip ring. Can be improved.

  Since no other stationary member is interposed between the tool main body 3 side and the socket main body 5 side, even when the nut 55 is located in a deep part of a narrow space, by holding the tool main body 3 The socket body 5 can be inserted into the narrow end of the socket body and a nut 55 can be fitted into the nut fitting portion 19 so that the fastening operation and the axial force detection can be easily performed, thereby greatly improving workability. it can.

  Moreover, the ultrasonic sensor 11 can be tilted with respect to the inner socket 7 in accordance with the tilt of the tip of the bolt 75 on the pin tail 83 side even if the pin tail 83 of the bolt 75 is tilted and inserted into the recess 35 of the inner socket 7. Therefore, the ultrasonic sensor 11 can be accurately brought into contact with the tip of the bolt 75 on the pin tail 83 side.

  With this accurate contact, the nut 55 can be fastened while preventing the bolt 75 from rotating, and the fastening can be completed while detecting the axial force by the ultrasonic sensor 11.

  The ultrasonic sensor 11 can be tilted by a spherical support with respect to the inner socket 7.

  Therefore, the ultrasonic sensor 11 can be accurately tilted with respect to the inner socket 7 in accordance with the inclination of the tip end of the bolt 75 on the pin tail 83 side.

  The inner socket 7 is provided with a spherical receiving portion 63 urged by a spherical urging spring 61, and the ultrasonic sensor 11 is in contact with the spherical receiving portion 63 to provide spherical support to the inner socket 7. A spherical contact portion 65 is provided.

For this reason, the ultrasonic sensor 11 can be tilted easily and accurately according to the tilt of the tip end of the bolt 75 on the pin tail 83 side by the elastic contact of the spherical contact portion 65 with the spherical receiving portion 63.
[Others]
The tiltable support of the ultrasonic sensor with respect to the inner socket is such that the support member is rotatably supported around an axis orthogonal to the axial direction of the inner socket, and the rotation axis orthogonal to the rotation axis of the support member is used. It is also possible to cause the ultrasonic sensor to be supported by a support member so as to be rotatable.

It is a partially omitted sectional view showing an axial force detection fastening tool in a state at the time of fastening. (Example 1) It is a principal part expanded sectional view which shows an axial force detection fastening tool in the state at the time of fastening. (Example 1) It is a partially-omitted sectional view showing the axial force detection fastening tool in a non-fastened state. (Example 1) It is a principal part expanded sectional view which shows tilting of the ultrasonic sensor at the time of fastening operation. (Example 1) It is sectional drawing which shows the state which has fastened the volt | bolt with the axial force detection fastening tool. (Conventional example)

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Axial force detection fastening tool 3 Tool body 5 Socket body 7 Inner socket 9 Drive transmission mechanism 11 Ultrasonic sensor 16 Inner socket support cylinder (support part)
17 Inner spline 19 Nut fitting part 35 Recessed part (locking part)
37 Inner serration (locking part)
45 Sensor spring (biasing member)
55 Nut 61 Spherical urging spring (spherical urging member)
63 Spherical surface receiving part 65 Spherical surface contact part 75 Bolt 83 Pin tail (engaging part)

Claims (3)

An axial force detection fastening tool for tightening a nut while detecting an axial force on a bolt provided with an engagement portion in a rotational direction along the axial direction on the outer periphery of the tip,
Rotation of a rotary actuator on the bolt provided with a nut fitting portion for fitting the nut and rotatably supported by the tool main body, and the nut fitted to the nut fitting portion being prevented from rotating with respect to the tool main body Socket body that can be tightened by rotating around the axis with drive output,
A support part on the tool body side formed concentrically with respect to the socket body;
The bolt body is concentrically disposed on the socket body and the support portion, faces the nut fitting portion, is non-rotatable with respect to the support portion, and is axially movable supported and retracted from the nut fitting portion. An inner socket provided with an engaging portion on the tip side inner periphery that is fitted and supported to prevent rotation with respect to the tool body,
A biasing member that biases the inner socket against the support and faces the nut fitting portion;
An ultrasonic sensor for detecting the axial force of the bolt, which is supported by the axial center portion of the inner socket along the axial direction and is input to the front end of the bolt on the locking portion side With
The support of the ultrasonic sensor with respect to the inner socket can be tilted in accordance with the inclined insertion of the engagement portion side tip of the bolt.
Axial force detection fastening tool characterized by that. In the axial force detection fastening tool according to claim 1,
The ultrasonic sensor can be tilted by a spherical support for the inner socket,
Axial force detection fastening tool characterized by that. In the axial force detection fastening tool according to claim 1 or 2,
The inner socket is provided with a spherical receiving portion biased by a spherical biasing member,
The ultrasonic sensor is provided with a spherical abutting portion that abuts on the spherical receiving portion and provides spherical support to the inner socket.
Axial force detection fastening tool characterized by that.

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