JP2016013595A - Nut fastener - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance the functionality and usability of a nut fastener by applying a shear wrench for fastening a hexagon nut to a normal bolt by using a reaction washer, in the shear wrench which is a fastening tool for fastening a nut to a shear bolt, and makes a user hardly receive a reaction of fastening by cutting a chip at a fastening final stage, and absorbing reaction torque.SOLUTION: A nut fastener is made to function as a combined machine which is adapted to both a first fastening mode in which a hexagon nut is fastened to a shear bolt, a chip part is sheared at a fastening final stage, and reaction torque is absorbed, and a second fastening mode in which the hexagon nut N2 is fastened to a normal bolt R while absorbing the reaction torque by using a reaction washer Z. Since the nut fastener is adapted to both the fastening modes by exchanging an outer socket 40 and an inner socket 41, the functionality and the usability of the nut fastener 1 are enhanced.

Description

  The present invention relates to a nut tightening machine called a shear wrench.

  This nut tightening machine is a hand-held tool for tightening a nut to a bolt called a torcher bolt (hereinafter simply referred to as a shear bolt), an outer socket that fits the nut on the inner peripheral side and rotates in the tightening direction. And an inner socket that shears the tip portion of the shear bolt by rotating in a direction opposite to the outer socket in a state where the tip portion (pin tail) of the shear bolt is fitted on the inner peripheral side.

  At the beginning of the nut tightening (temporary tightening stage), the outer socket rotates (rotates clockwise) in the nut tightening direction. The inner socket does not rotate at the temporary tightening stage. As a result, the shear bolt is fixed so as not to rotate with the nut. When a large external torque is applied to the outer socket at the final stage of tightening, the inner socket rotates in the opposite direction to the outer socket (rotates counterclockwise) by the tightening reaction force. When the inner socket rotates counterclockwise at the final stage of tightening, the shear bolt tip portion is sheared to receive a tightening reaction force. The sheared chip portion is pushed out from the inner socket by the chip discharge rod and discharged.

  A technique related to a nut tightening machine called a shear wrench is disclosed in the following patent document. Patent Document 1 discloses a technique for turning off the main switch and automatically stopping the rotation driving of the outer socket regardless of the pulling operation of the switch lever when the tightening torque of the nut reaches a constant torque. Patent Document 2 discloses a technique related to a shock absorbing protector.

Japanese Patent Laid-Open No. 11-871 JP 2012-35382 A

  However, a conventional general shear wrench is a dedicated machine that tightens a hexagonal nut against a Torcher bolt, and for example, it cannot receive a tightening reaction force when tightening a nut to a normal bolt that does not have a tip portion. It could not be used as it is. Here, when fastening a hexagon nut to a normal bolt having no tip part, a technique for receiving a fastening reaction force using a so-called reaction force washer is known. By using this reaction force washer, the reaction force washer receives a reaction torque in the direction opposite to the nut tightening direction at the final tightening stage, thereby receiving the tightening reaction force. For this reason, it is not necessary to take the trouble of receiving a tightening reaction force by providing a reaction force lever on the socket for rotating the nut and bringing it into contact with the periphery, and the working efficiency can be significantly improved. However, when a reaction force washer is used, a dedicated machine having both a socket for tightening a nut and a socket for applying a reaction torque to the reaction force washer is required.

  From the above, a special machine called a shear wrench is prepared when tightening a nut on a conventional torque shear bolt, and another special machine is used when tightening a nut on a normal bolt using a reaction washer. It was necessary to prepare, and in this respect, the workability of each dedicated machine was poor. An object of the present invention is to provide a dual-purpose machine that can be used for both a tightening operation of a nut to a Torcher bolt and a tightening operation of a nut to a normal bolt using a reaction washer.

  The above-described problems are solved by the following inventions. The first invention is a nut tightening machine that can also use two tightening modes. In the first tightening mode, the first nut is fastened to the first bolt, and the tip portion of the first bolt is sheared to absorb the reaction torque generated by the nut tightening. For this reason, in the first tightening mode, the first outer socket for rotating the first nut in the tightening direction and the first inner socket for rotating the tip portion in the direction opposite to the first nut and shearing are mounted. Is done.

  In the second tightening mode, the reaction torque (tightening reaction force) generated by tightening the nut is absorbed by tightening the second nut on the second bolt using the reaction force washer. Therefore, in the second tightening mode, instead of the first inner socket, a second inner socket that rotates the second nut in the tightening direction with respect to the second bolt is mounted, and the first outer socket is mounted. Instead, a second outer socket for attaching a reaction torque to the reaction force washer is attached. In the second tightening mode, the electric motor is activated in the direction opposite to that in the first tightening mode, and the second nut is tightened.

  According to the first invention, one nut tightening machine is tightened by tightening the first nut to a first bolt called a so-called Torcher bolt and shearing the tip portion of the first bolt. The first tightening mode (shear wrench mode) that absorbs the reaction torque generated by the second tightening, and the second tightening that tightens the second nut to the second bolt (ordinary bolt without a tip) using the reaction force washer It can also be used as a mode (reaction force washer mode).

  2nd invention is a nut clamping machine provided with the outer sleeve and inner sleeve which rotate in the mutually opposite direction in 1st invention. In the first tightening mode, the first outer socket is attached to the outer sleeve, the first inner socket is attached to the inner sleeve, and the first nut is fitted to the nut fitting portion of the first outer socket. Then, with the tip portion of the first bolt fitted to the tip fitting portion of the first inner socket, the first outer socket is rotated in the nut tightening direction to turn the first nut into the first bolt. While tightening, the first inner socket is rotated in the opposite direction to the first outer socket to shear the tip portion, thereby absorbing the reaction torque generated by tightening the first nut.

  In the second tightening mode, instead of the first outer socket, a second outer socket having a washer fitting portion for fitting a reaction force washer is attached to the outer sleeve, and the first inner socket is replaced. The second inner socket having the second nut fitting portion is attached to the inner sleeve, the reaction washer is fitted to the washer fitting portion, and the second nut is fitted to the second nut fitting portion. In the engaged state, the electric motor is activated in the direction opposite to the first tightening mode. As a result, the second inner socket is rotated in the nut tightening direction to tighten the second nut to the second bolt, and the second inner socket is restrained in the rotational direction by tightening, whereby the second outer socket. A reaction torque in the direction opposite to the nut tightening direction is applied to the reaction force washer through the socket to absorb the tightening reaction force.

  According to the second invention, in one nut tightening machine, the electric motor is started in the reverse direction, so that the combined use of the first tightening mode and the second tightening mode is realized. In the first tightening mode, the first outer socket and the first inner socket are used. In the second tightening mode, the first outer socket and the first inner socket are exchanged with the second outer socket and the second inner socket. The first tightening mode for tightening the nut to the shear bolt and the second tightening mode using the reaction force washer can be combined by simply replacing the outer sleeve and the socket attached to the inner sleeve.

  A third invention is a nut tightening machine according to the first or second invention, wherein the second outer socket and the second inner socket are assembled. According to the third aspect, in the second tightening mode, it is possible to improve the handleability of the second outer socket and the second inner socket.

  According to a fourth invention, in any one of the first to third inventions, in the second tightening mode, the electric motor is automatically stopped when the second nut is tightened with a constant torque. Before the electric motor automatically stops, the electric motor once reverses and the biting of the second inner socket with respect to the second nut is released. When the second nut is tightened with a constant torque, a constant external torque is applied to the second inner socket. When a constant external torque is applied to the second inner socket, the current value supplied to the electric motor reaches a constant value, which is detected by the motor controller. In the motor controller, when a constant current value is detected, the electric motor is once reversely rotated (reverse to the nut tightening direction) and then stopped.

  According to the fourth invention, when the second nut is tightened with a constant torque, the second inner socket is slightly reversed to release the biting with respect to the second nut. For this reason, the second inner socket and thus the nut tightening machine can be easily detached from the second nut. The reverse rotation for releasing the biting of the second inner socket with respect to the second nut is performed at an angle necessary and sufficient to release the biting, and the tightened state of the second nut once tightened is performed. It will not rotate backwards until it is loosened. In addition, since the electric motor is automatically stopped by the motor controller after the bite is released in this way, the electric motor is automatically stopped even if the user keeps turning on the switch lever after the tightening is completed. Damage such as seizure can be prevented in advance, and thereby the durability of the electric motor can be enhanced.

  A fifth invention is a nut tightening machine according to the fourth invention, wherein the current value detected by the motor controller can be changed in accordance with the size of the second nut. According to the fifth aspect of the invention, by changing the constant current value (threshold for automatic motor stop) detected by the motor controller in accordance with the size of the second nut to be tightened, the second nut can be appropriately adjusted. While securing the tightening torque, it is possible to realize the release of the bite and the automatic stop of the electric motor.

It is a whole perspective view of a nut bolting machine concerning an embodiment of the present invention. This figure has shown the state which mounted | wore with the 1st outer socket and the 1st inner socket corresponding to the 1st fastening mode. It is a longitudinal cross-sectional view of the nut fastening machine which concerns on this embodiment. This figure is shown in a state corresponding to the first tightening mode (shire wrench mode). It is a longitudinal cross-sectional view of the nut fastening machine which concerns on this embodiment. This figure has shown the state which removed the socket from the outer sleeve and the inner sleeve. It is a longitudinal cross-sectional view of the nut fastening machine which concerns on this embodiment. This figure is shown in a state corresponding to the second tightening mode (reaction force washer mode). It is a block diagram of a motor control circuit. It is a figure which shows the flowchart of the nut clamping machine of this embodiment. It is a figure which shows the flowchart of 2nd fastening mode of an automatic stop type. The flow shown in this figure includes a nut biting release function. It is a figure which shows the flowchart of 1st fastening mode of a manual stop type. It is a figure which shows the flowchart of 2nd fastening mode of an automatic stop type. In the flow shown in this figure, the nut biting release function is omitted.

  Next, an embodiment of the present invention will be described with reference to FIGS. 1 and 2 show a nut tightening machine 1 according to the present embodiment. The nut tightening machine 1 of the present embodiment described below includes a first tightening mode (shear wrench mode) used as a shear wrench for tightening a first nut N1 (hexagonal nut) to the torque shear bolt S, and a reaction washer. This is a dual-purpose machine that can select the second tightening mode (reaction force washer mode) for tightening the second nut N2 (hexagonal nut) to the bolt. In any tightening mode, the reaction torque generated by tightening the nut can be absorbed or significantly reduced.

  In the following description, the Torcher bolt S to be tightened in the first tightening mode corresponds to the first bolt. The outer socket 18 used in the first tightening mode corresponds to the first outer socket, and the inner socket 19 corresponds to the first inner socket. Furthermore, the normal bolt (bolt which does not have a sheared tip part) fastened in the second fastening mode corresponds to the second bolt. The outer socket 40 used in the second tightening mode corresponds to the second outer socket, and the inner socket 41 corresponds to the second inner socket.

  The nut tightening machine 1 according to the present embodiment includes a tool main body 10, a motor 20, and a D-shaped handle 30 that is gripped by a user. The motor unit 20 is provided in a state of protruding downward from the side of the tool body unit 10. A handle portion 30 is provided behind the motor portion 20. A power supply cord 31 for supplying power is drawn into the lower portion of the handle portion 30. This AC power cord 31 supplies commercial AC power. In this embodiment, the nut clamping machine 1 of AC power supply specification is illustrated.

  The electric motor 2 is housed in the motor case 2e of the motor unit 20. The electric motor 2 is activated when the main switch 4 is turned on by turning on a trigger type switch lever 3 provided on the upper front surface of the handle portion 30. The electric motor 2 includes a rotor 2c fixed to the output shaft 2b, and a stator 2d disposed around the rotor 2c. The stator 2d has a wound coil. A motor cooling fan 2h is attached to the top of the output shaft 2b. The rotation of the electric motor 2 is transmitted to the intermediate shaft 7 through the pinion gear 2a, the intermediate gear 5, and the intermediate gear 6 formed at the tip of the output shaft 2b. A bevel gear 7 a is formed at the tip of the intermediate shaft 7 and meshes with the bevel gear 8. The bevel gear 8 is rotatably supported by the main body case 9 via bearings 8a and 8b. The rotation axis of the bevel gear 8 coincides with the machine axis J of the tool body 10.

  The rotational output of the bevel gear 8 is transmitted to the inner sleeve 14 and the outer sleeve 16 via the first to third stage planetary gear trains 11 to 13. The first stage planetary gear train 11 includes a first stage sun gear 8c, a first stage planetary gear 11b, a first stage carrier 11a, and a first stage internal gear 11c provided integrally with the bevel gear 8. Yes. The second stage planetary gear train 12 includes a second stage sun gear 12c, a second stage planetary gear 12b, a second stage carrier 12d, and a second stage internal gear 12a provided integrally with the first stage carrier 11a. doing. The third-stage planetary gear train 13 includes a third-stage sun gear 13c, a third-stage planetary gear 13d, a third-stage carrier 13a, and a third-stage internal gear 13b that are provided integrally with the second-stage carrier 12d. doing.

  The inner sleeve 14 is integrated with respect to the rotation about the axis J with respect to the third stage carrier 13 a of the third stage planetary gear train 13. For this reason, the inner sleeve 14 rotates integrally with the rotation of the third stage carrier 13a. The outer sleeve 16 is integrated with the front case 17 for rotation around the axis J. The front case 17 is supported so as to be rotatable about the machine axis J with respect to the main body case 9. A third-stage internal gear 13 b is fixed to the inner peripheral surface of the front case 17. For this reason, the front case 17 and the outer sleeve 16 rotate together by the rotation of the third-stage internal gear 13b. The third stage carrier 13a and the inner sleeve 14 are rotatably supported through the inner ring side of the bearing 15, and the third stage internal gear 13b, the outer sleeve 16 and the front case 17 rotate through the outer ring side of the bearing 15. Supported as possible.

  Since the rotation direction of the third stage carrier 13a (revolution direction of the planetary gear) and the rotation direction of the third stage internal gear 13b are opposite to each other, the inner sleeve 14 and the outer sleeve 16 are opposite to each other. Rotate. An outer socket 18 is coupled to the front end of the outer sleeve 16 as a first outer socket for the first tightening mode. A nut fitting portion 18 a into which the first nut N <b> 1 can be fitted is provided on the inner peripheral surface of the outer socket 18.

  The outer socket 18 is coupled to the outer sleeve 16 so as to be axially displaceable and not rotatable relative to the axis. The outer socket 18 is disposed coaxially with the inner sleeve 14. The outer socket 18 can be removed by moving it forward with respect to the outer sleeve 16. Instead of the outer socket 18 that is the first outer socket, an outer socket 40 as a second outer socket described later can be attached to the outer sleeve 16. Four engaging recesses 18b to 18b are provided on the outer peripheral surface of the rear portion of the outer socket 18. On the other hand, four engaging protrusions 16 a to 16 a are provided on the outer peripheral surface of the front portion of the outer sleeve 16. The four engagement recesses 18b to 18b and the four engagement protrusions 16a to 16a are respectively provided at the four positions in the circumferential direction. By inserting the rear side of the outer socket 18 into the inner peripheral side of the outer sleeve 16 and attaching the engagement projections 16a into the respective engagement recesses 18b, the outer socket 18 is attached to the outer sleeve 16. On the other hand, it will be in the state integrated about rotation.

  An inner socket 19 is supported on the inner peripheral side of the inner sleeve 14 and the outer socket 18. The inner socket 19 is urged forward with respect to the inner sleeve 14 by a compression spring 34. The outer peripheral side of the inner socket 19 is splined to the inner peripheral surface of the inner sleeve 14. Thereby, the inner sleeve 14 and the inner socket 19 are integrated with respect to the rotation around the machine axis J.

  A chip fitting portion 19 a is provided on the inner peripheral surface of the inner socket 19. A slick prevention pin 37 protrudes into the chip fitting portion 19a. The lick prevention pin 37 is urged toward the protruding side with respect to the inner socket 19 by the compression spring 32. When the chip portion Sa is completely fitted into the chip fitting portion 19a of the inner socket 19 and the slick prevention pin 37 is retracted from the chip fitting portion 19a, the stopper 33 provided on the peripheral surface of the inner socket 19 is moved. By retracting to the inner peripheral side of the inner socket 19, the inner socket 19 can move to the inner side of the inner sleeve 14. According to this configuration, if the tip portion Sa is not completely fitted to the tip fitting portion 19a of the inner socket 19, the first nut N1 is fitted to the nut fitting portion 18a of the outer socket 18. As a result, licking of the chip portion Sa is prevented.

  According to the driving force transmission path and the tightening mechanism configured as described above, the tip portion Sa is first inserted into the tip of the inner socket 19 with respect to the shear bolt S to which the first nut N1 is temporarily tightened as shown in FIG. Insert into the joint 19a. The anti-slick pin 37 and the push pin 36 are retracted against the compression spring 32 to completely insert the tip portion Sa into the tip fitting portion 19a. Thereafter, the inner socket 19 is retracted against the compression spring 34, whereby the first nut N <b> 1 is fitted into the nut fitting portion 18 a of the outer socket 18. At this stage, the inner socket 19 is splined to the inner sleeve 14. In this state, when the switch lever 3 is turned on to activate the electric motor 2, the outer socket 18 rotates and the first nut N1 is tightened to the shear bolt S.

  When the tightening of the first nut N1 reaches the final stage and a large reaction torque is applied to the outer socket 18, the rotation of the third-stage internal gear 13b is restricted and the third-stage carrier 13a rotates in the opposite direction. Therefore, the inner socket 19 rotates in the direction opposite to the nut tightening direction. Thus, the tip portion Sa of the shear bolt S is sheared (cut) by rotating the inner socket 19. The sheared tip portion Sa is discharged from the tip fitting portion 19a when the slick prevention pin 37 is projected forward by the compression spring 32. A discharge lever 35 is provided above the switch lever 3. When the discharge lever 35 is pulled, the push pin 36 is forcibly moved to the front side (left side in FIG. 2), and the tip portion Sa sheared thereby is forcibly removed from the tip fitting portion 19a.

  As described above, the nut tightening machine 1 of the present embodiment uses the reaction force washer Z to replace the second nut N2 (hexagonal nut) with the second bolt R instead of the first tightening mode used as a shear wrench. It can also be used in the second tightening mode for tightening. As described above, the outer socket 18 can be detached from the outer sleeve 16. Further, the inner socket 19 can be removed from the inner sleeve 14. Further, the lick prevention pin 37, the push pin 36, and the compression springs 32 and 34 can be removed from the inner peripheral side of the inner sleeve 14. FIG. 3 shows a state in which all of these are removed.

  In order to use the nut tightening machine 1 of the present embodiment in the second tightening mode, the outer socket 18 is removed from the outer sleeve 16 and the inner socket 19 is removed from the inner sleeve 14 as shown in FIG. 37, after removing all of the push pin 36 and the compression springs 32, 34, the second outer socket 40 is attached to the outer sleeve 16 and the second inner socket 41 is attached to the inner sleeve 14, as shown in FIG. . In the case of this embodiment, the second outer socket 40 and the second inner socket 41 are assembled by set screws 42 and 42 so that they can be handled integrally. The assembled second outer socket 40 and second inner socket 41 can be simultaneously inserted into the outer sleeve 16 and the inner sleeve 14 and mounted.

  A washer fitting portion 40 a for fitting the reaction force washer Z is provided on the inner peripheral surface of the second outer socket 40. The reaction force washer Z is provided with, for example, twelve corrugated protrusions around the reaction washer Z. In the case of this embodiment, a known reaction force washer Z can be used as it is. A nut fitting portion 41 a for fitting the second nut N <b> 2 is provided on the inner peripheral surface of the second inner socket 41. As shown in the drawing, the second nut N2 temporarily tightened to the second bolt R with a constant torque is fitted into the nut fitting portion 41a of the second inner socket 41, and the reaction force washer Z is attached to the second outer washer. The nut tightening machine 1 can be used in a state of being fitted in the washer fitting portion 40 a of the socket 40.

  In the second tightening mode, the rotation direction of the electric motor 2 (the rotation direction of the output shaft 2b) is switched to the opposite direction to the first tightening mode. The rotation direction of the electric motor 2 can be switched by a mode switch 23 provided on the lower side surface of the motor unit 20. When the mode changeover switch 23 is a seesaw type switch and pushes the "S" display side on the left side of the figure, the electric motor 2 rotates forward and is switched to the first tightening mode. When the electric motor 2 rotates in the forward direction, the first outer socket 18 rotates in the nut tightening direction (clockwise if the first nut N1 is a right-hand thread), and the first nut N1 is turned to the first bolt S. In addition to being tightened, the inner socket 19 is rotated in the anti-nut tightening direction (when the first nut N1 is a right-handed screw, it rotates counterclockwise), and the tip portion Sa is sheared. In the following description, the rotation direction (forward rotation direction) of the electric motor 2 in the first tightening mode is referred to as the first rotation direction, and the rotation direction (reverse rotation direction) of the electric motor 2 in the second tightening mode is the first. The second rotation direction is opposite to the rotation direction.

  When the “H” display side on the right side of the mode switch 23 is pressed, the nut tightening machine 1 is switched to the second tightening mode. The rotation direction of the electric motor 2 is switched to the second rotation direction by pushing the “H” display side of the mode changeover switch 23, and the second nut N2 is fitted into the second inner socket 41 as described above. When the reaction lever washer Z is fitted in the outer socket 40 of No. 2 and the switch lever 3 is pulled, the electric motor 2 starts in the second rotational direction. When the electric motor 2 is started in the second rotation direction, the second inner socket 41 is moved through the first to third stage planetary gear trains 11 to 13 in the nut tightening direction (if the second nut N2 is a right-hand thread). The second nut N2 is fastened to the second bolt R by rotating clockwise. Since the reaction force washer Z is accompanied by a large rotational resistance due to the temporary tightening of the second nut N2, it does not rotate, and therefore the second outer socket 40 also does not rotate.

  When the second nut N2 is tightened with a constant torque and a large rotational resistance is applied to the second inner socket 41, the reaction torque is applied to the third-stage internal gear 13b, the front case 17, the outer sleeve 16, and the second sleeve. 2 is received by the reaction force washer Z (the frictional resistance between the reaction force washer Z and the member) as an external force in the nut tightening direction through the outer socket 40. When the reaction torque generated by the nut tightening is received by the reaction force washer Z as described above, the tightening reaction received by the user using the nut tightening machine 1 can be greatly reduced.

  In the nut tightening machine 1 of the present embodiment, when the second nut N2 is tightened with a constant tightening torque in the second tightening mode, the second inner socket 41 is slightly reversed in the anti-nut tightening direction. After the biting on the nut N2 of 2 is released, the electric motor 2 is automatically stopped. For this reason, in the second tightening mode, even if the user keeps the switch lever 3 turned on (pulling operation), if the second nut N2 is tightened with a constant torque, the second nut After the biting of the second inner socket 41 with respect to N2 is released, the electric motor 2 is automatically stopped. The nut tightening machine 1 of this embodiment includes a motor control device 50 for operating the electric motor 2 as described above in the second tightening mode. FIG. 5 shows an outline of the motor control device 50. 6 to 9 show flowcharts of operation control performed by the motor control device 50.

  As described above, when the second nut N2 is tightened with a constant torque by the rotation of the second inner socket 41, a constant external torque is applied to the second inner socket 41. When a constant external torque is applied to the second inner socket 41, the current value supplied to the electric motor 2 reaches a constant value. The current value supplied to the electric motor 2 is detected by the motor controller 21. In the motor controller 21, when a constant current value is detected, the electric motor 2 is stopped from rotating in the nut tightening direction, and then the electric motor 2 is reversely rotated by a slight angle. Furthermore, in the motor controller 21, after the electric motor 2 is reversed by a small angle, the electric power supply to the electric motor 2 is cut off and automatically stopped.

  When the second nut N2 is tightened with a constant torque, the constant current value (threshold for automatic motor stop) detected by the motor controller 21 can be adjusted according to the size of the second nut N2. it can. An adjustment dial 22 is provided behind the mode switch 23. By rotating the adjustment dial 22, the current value for automatic motor stop can be changed according to the size of the second nut N2. As a result, the biting release function of the second inner socket 41 with respect to the second nut N2 and the automatic stop of the electric motor 2 are ensured while securing the original function of tightening the second nuts N2 of various sizes with appropriate torques. Function can be realized. The adjustment dial 22 displays “0, 1, 2, 3,..., 9”. Each numerical value corresponds to a screw diameter of a nut that can be tightened (first nut N1 or second nut N2). For example, “3” corresponds to M16, “5” corresponds to M20, “7” corresponds to M22, and “9” corresponds to M24. Therefore, instead of displaying “0, 1, 2, 3,..., 9”, the thread diameter may be directly displayed.

  As shown in FIG. 5, the motor control device 50 includes a motor controller 21 including a CPU (Central Processing Unit). In addition to the motor current value as described above, the motor controller 21 outputs the “screw diameter signal” output from the adjustment dial 22, the mode switching signal output from the mode switch 23, and the main switch 4. “ON signal” is input. Based on these input signals and information, a control signal is output from the motor controller 21 to the motor drive 24, thereby controlling the operation of the electric motor 2 such as start / stop and rotation direction.

  As shown in FIG. 6, when the main switch 4 is turned on, an on signal is input to the motor controller 21 (step 01, hereinafter abbreviated as “ST01”). When the ON signal of the main switch 4 is input, the mode switching signal is confirmed (ST02). If it is confirmed in ST03 that it is not the second tightening mode, it is confirmed in ST04 whether or not it is the first tightening mode. If the mode is not the first tightening mode, the mode switching signal is continuously confirmed in ST02. If it is confirmed in ST04 that the first tightening mode is selected, the process proceeds to the first tightening mode (ST05). The first tightening mode shown in FIG. 8 will be described later.

  If it is confirmed in ST03 that the second tightening mode is selected, the process proceeds to the second tightening mode (ST06). As shown in FIG. 7, when the flow of the second tightening mode is started in ST07, the screw diameter information is read in ST08. The screw diameter information is made based on the output signal of the adjustment dial 22. By reading the screw diameter information, the set value of the tightening torque is determined, and the current value threshold for the electric motor 2 at this time is set.

  Next, in ST09, a signal for starting the electric motor 2 in the second rotation direction (reverse rotation direction) is output, and the electric motor 2 is started in the second rotation direction. When the electric motor 2 is activated, the inner socket 19 is rotated and the second nut N2 is tightened to the second bolt R. In this process, the change in the current value flowing through the electric motor 2 is monitored (ST10). In ST11, it is determined whether or not the value of the current flowing through the electric motor 2 has reached a certain value. If the current value to the electric motor 2 does not reach a certain value, the current value is continuously monitored in ST10. During tightening of the second nut N2, the reaction force washer Z is fitted into the washer fitting portion 40a of the second outer socket 40 and its rotation is restricted.

  When the tightening torque of the second nut N2 with respect to the second bolt R reaches a constant value, the reaction torque is received by the second outer socket 40 and the reaction force washer Z. Further, when the tightening torque of the second nut N2 reaches a constant value, the value of the current flowing through the electric motor 2 reaches a constant value.

  When it is confirmed in ST11 that the motor current value has reached a constant value, the electric motor 2 is temporarily stopped in ST12, and the tightening of the second nut N2 is stopped. Immediately after the rotation operation of the electric motor 2 in the second rotation direction is stopped, the electric motor 2 is rotated by a slight angle in the first rotation direction (forward rotation direction) in ST13. Thus, when the electric motor 2 is rotated by a slight angle in the direction opposite to the tightening direction of the second nut N2, the biting (galling) of the inner socket 19 with respect to the second nut N2 is released (biting of the nut). Release function). By releasing the biting of the inner socket 19 with respect to the second nut N2, the inner socket 19 can be easily detached from the second nut N2, so that the user can tighten the nut tightening machine 1 to the tightening portion. Work can be finished away from After the biting of the second nut N2 is released in ST13, the electric motor 2 is automatically stopped in ST14. The second tightening mode routine is thus completed.

  Next, when it is confirmed in ST04 that the first tightening mode is selected, the process proceeds to the first tightening mode in ST05. When the first tightening mode is started in ST15, the electric motor 2 is started in the first rotation direction (forward rotation direction) because the mode switch 23 is switched to the “S” side. By starting in the first rotation direction, the outer socket 19 rotates in the nut tightening direction, and the first nut N1 is tightened to the first bolt S (shear bolt).

  When the first nut N1 is tightened with an appropriate torque, the inner socket 19 is slightly rotated in the reverse direction by the reaction torque generated by restricting the rotation of the outer socket 18, and the tip portion Sa is sheared. By shearing the tip portion Sa, the tightening torque of the first nut N1 is properly managed, and the reaction torque generated by the tightening is absorbed.

  In the tightening process, the on signal of the main switch 4 is not detected in ST17, and the on / off state of the main switch 4 is determined in ST18. When the ON state of the main switch 4 is confirmed in ST18, the process returns to ST17 and the activation state of the electric motor 2 is maintained. In the first tightening mode, the tip portion Sa is sheared after the completion of the tightening of the first nut N1, and as a result, the inner socket 19 is allowed to rotate in the reverse direction (idle). There is no problem even if it is maintained.

  If it is confirmed in ST18 that the main switch 4 is turned off, the electric motor 2 is stopped in ST19. As described above, in the first tightening mode, after the first nut N1 is tightened with an appropriate torque and the chip Sa is sheared, the electric motor 2 is maintained in the activated state when the switch lever 3 is turned on, and the switch lever At the time when 3 is turned off, the electric motor 2 is manually stopped. Therefore, ST15 to ST19 indicate a first manual tightening mode in which the electric motor 2 is maintained in the activated state unless the switch lever 3 is turned off. In the first tightening mode of the manual stop type, the control by the motor controller 21 based on the reading of the screw diameter setting and the setting of the motor current value made in the second tightening mode is omitted.

  According to the nut tightening machine 1 of the present embodiment configured as described above, the first tightening mode for tightening the first nut N1 to the first bolt (shear bolt S), and the second bolt (normal bolt). A dual-purpose machine capable of supporting the second tightening mode for tightening the second nut N2 to R) can be provided. If the main parts such as the tool body 10, the motor 20, and the handle 30 are shared and the outer socket 18 (40) and the inner socket 19 (41) are replaced, the first or second tightening mode can be supported. Since it can do, the functionality and usability of the nut tightening machine 1 can be greatly improved.

  In the second tightening mode, when the second nut N2 is tightened with a constant torque, the reaction torque is received by the reaction force washer Z through the second outer socket 40, and the second inner socket 41 Slightly rotates in the anti-tightening direction, and the biting of the second inner socket 41 with respect to the second nut N2 is released. As a result, the user can operate the nut tightening machine 1 by smoothly removing the second inner sleeve 41 from the second nut N2 without receiving a reaction torque due to the tightening of the second nut N2. Can be pulled away from the site.

  Further, in the second tightening mode, the reaction torque is absorbed by the reaction force washer Z as described above, and after the biting against the second nut N2 is released, the electric motor 2 is automatically stopped. For this reason, even if the user keeps the switch lever 3 on, when the second nut N2 is tightened with a constant torque, the reaction torque is absorbed by the reaction force washer Z, and the second nut N2 After the biting of the second inner socket 41 with respect to the nut N2 is released, the electric motor 2 is automatically stopped. For this reason, even if the switch lever 3 is kept in the ON operation state, the starting state of the electric motor 2 is not continued unnecessarily, thereby suppressing wasteful power consumption and burning the electric motor 2. Can be prevented in advance, and as a result, the durability of the electric motor 2 can be improved.

  Further, the controller 21 is provided with an adjustment dial 22. By rotating the adjustment dial 22, the threshold value of the current value for automatically stopping the electric motor 2 can be changed according to the size of the second nut N2 to be tightened. Therefore, according to the present embodiment, the reaction torque is absorbed by the reaction washer Z while securing an appropriate tightening torque according to the size of the second nut N2 of various sizes, and the second nut N2 And the durability of the electric motor 2 can be increased by automatically stopping the electric motor 2. According to the automatic stop function of the electric motor 2, a great effect can be obtained in that useless power consumption can be eliminated when the power source is a battery pack.

  Various modifications can be made to the embodiment described above. For example, although an AC machine with an AC power supply is illustrated, a similar configuration can be applied to a rechargeable nut tightening machine that uses a battery pack that can be repeatedly used by charging as a power source.

  Moreover, although the 2nd outer socket 40 and the 2nd inner socket 41 were assembled by the set screw 42, the structure attached and removed integrally was illustrated, it is good also as a structure attached and removed separately, respectively.

  Further, in the second tightening mode, the configuration in which the variation in the current value of the electric motor 2 is detected and the tightening torque of the nut is detected is exemplified. However, instead of the current detection method, the variation in the rotation speed of the electric motor 2 is illustrated. It is good also as a structure which detects that the fastening torque reached a fixed value by detecting. The rotation speed of the electric motor 2 can be detected, for example, by counting the rotation speed of a magnet attached to the output shaft with a sensor.

  Furthermore, according to the exemplified motor controller 21, the configuration in which the electric motor 2 is controlled so that the nut biting release function and the automatic stop function of the electric motor 2 are exhibited only in the second tightening mode is described. It is good also as a structure which controls the electric motor 2 with the said motor controller 21 so that the same function may be exhibited also in 1 fastening mode.

  Further, in the second tightening mode shown in FIG. 7, the configuration in which the electric motor 2 is reversed in ST13 to release the biting of the second nut N2 with respect to the inner socket 19 (nut biting release function) is illustrated. The biting release function can be omitted. FIG. 9 shows a flow of the second tightening mode in which the automatic stop function of the electric motor 2 is provided, but the function of releasing the biting with respect to the inner socket 19 of the second nut N2 is omitted. As shown in FIG. 9, when the second tightening mode of the automatic stop type is started in ST20, the electric motor 2 is similarly activated in the second rotation direction (reverse rotation direction) in ST21. When the electric motor 2 starts in the second rotation direction, the inner socket 19 rotates in the nut tightening direction, and the second nut N2 is tightened to the second bolt R.

  When the second nut N2 is tightened with an appropriate torque, the reaction torque generated by restricting the rotation of the inner socket 19 is received by the reaction washer Z through the outer socket 18.

  In the tightening process, a current value (motor current value) flowing through the electric motor 2 is detected in ST22. In ST23, a change in the motor current value is determined. At the stage where the tightening torque of the second nut N2 has not reached the constant torque, the change in the motor current value is not confirmed, and the routine returns to ST22. In the second tightening mode, the outer socket 18 does not rotate because it is restrained by the reaction force washer Z. For this reason, when the second nut N2 is tightened with an appropriate torque and the rotation of the inner socket 19 is restricted, the motor current value changes. When the change of the motor current value is confirmed in ST23, the electric motor 2 is automatically stopped in ST24.

  Thus, the nut biting release function (ST13) is omitted, and the second stop mode of the automatic stop type in which the routine is completed by stopping the electric motor 2 in accordance with the change in the motor current value is also the second. When the nut N2 is tightened with an appropriate torque, the electric motor 2 is automatically stopped even when the user keeps the switch lever 3 turned on, so that useless power consumption is suppressed.

S ... 1st bolt (Torscher bolt)
Sa ... Tip N1 ... First nut (hex nut)
R ... Second bolt N2 ... Second nut (hex nut)
Z ... Reaction force washer 1 ... Nut clamping machine 2 ... Electric motor 2a ... Pinion gear, 2b ... Output shaft, 2c ... Rotor, 2d ... Stator, 2e ... Motor case 3 ... Switch lever 4 ... Main switches 5, 6 ... Intermediate Gear 7 ... Intermediate shaft, 7a ... Bevel gear 8 ... Bevel gear, 8a, 8b ... Bearing, 8c ... First stage sun gear 9 ... Main body case 10 ... Tool body, J ... Axle 11 ... First stage planetary gear train 11a ... 1st stage carrier, 11b ... 1st stage planetary gear, 11c ... 1st stage internal gear 12 ... 2nd stage planetary gear train 12a ... 2nd stage internal gear, 12b ... 2nd stage planetary gear, 12c ... 2nd Stage sun gear, 12d ... 2nd stage carrier 13 ... 3rd stage planetary gear train 13a ... 3rd stage carrier, 13b ... 3rd stage internal gear, 13c ... 3rd stage sun gear, 13d ... 3rd stage planetary gear 14 ... Inner Three DESCRIPTION OF SYMBOLS 15 ... Bearing 16 ... Outer sleeve, 16a ... Engagement protrusion 17 ... Front case 18 ... 1st outer socket, 18a ... Nut fitting part 19 ... 1st inner socket, 19a ... Chip fitting part 20 ... Motor part DESCRIPTION OF SYMBOLS 21 ... Motor controller 22 ... Adjustment dial 23 ... Mode changeover switch 24 ... Motor drive 30 ... Handle part 31 ... Power supply cord 32 ... Compression spring 33 ... Stopper 34 ... Compression spring 35 ... Discharge lever 36 ... Extrusion pin 37 ... Slack prevention pin DESCRIPTION OF SYMBOLS 40 ... 2nd outer socket, 40a ... Washer fitting part 41 ... 2nd inner socket, 41a ... Nut fitting part 42 ... Set screw 50 ... Motor control apparatus

Claims (5)

A nut tightening machine that tightens a first nut on a first bolt using an electric motor as a driving source and shears a tip portion of the first bolt,
A first tightening mode in which a first outer socket that rotates the first nut in a tightening direction and a first inner socket that rotates and shears the tip portion in a direction opposite to the first nut; ,
Instead of the first inner socket, a second inner socket that rotates the second nut in the tightening direction with respect to the second bolt is mounted, and the second outer socket is replaced with the second inner socket. A second outer socket for applying reaction torque generated by tightening the nut to the reaction washer is attached, and the electric motor is activated in a direction opposite to the first tightening mode to tighten the second nut. A nut tightening machine that can also be used in the second tightening mode. The nut tightening machine according to claim 1, comprising an outer sleeve and an inner sleeve rotating in opposite directions to each other,
In the first tightening mode, the first outer socket is attached to the outer sleeve, the first inner socket is attached to the inner sleeve, and the nut fitting portion of the first outer socket is attached to the nut fitting portion. The first nut is fitted, and the first outer socket is rotated in the nut tightening direction in a state where the tip part of the first bolt is fitted to the chip fitting part of the first inner socket. The first nut is tightened to the first bolt, and the tip portion is sheared by rotating the first inner socket in a direction opposite to the first outer socket. Absorbs the reaction torque generated by tightening,
In the second tightening mode, instead of the first outer socket, a second outer socket having a washer fitting portion for fitting the reaction force washer is attached to the outer sleeve, and the first sleeve is mounted. In place of the inner socket, a second inner socket having a second nut fitting portion is attached to the inner sleeve, the reaction washer is fitted to the washer fitting portion, and the second nut is fitted. In a state where the second nut is fitted to the fitting portion, the electric motor is activated in a direction opposite to the first tightening mode, and the second inner socket is rotated in the nut tightening direction. A second nut is fastened to the second bolt, and a reaction torque in a direction opposite to the nut tightening direction is applied to the reaction force washer through the second outer socket to add the second nut. Configuration and the nut tightening device to absorb a reaction force clamping occurs by tightening. The nut tightening machine according to claim 1 or 2, wherein the second outer socket and the second inner socket are assembled. The nut tightening machine according to any one of claims 1 to 3, wherein, in the second tightening mode, the second nut is tightened with a constant torque and fixed to the second inner socket. A motor controller for detecting a current value supplied to the electric motor at the time when torque is applied, and rotating the electric motor in reverse based on the current value detected by the motor controller; A nut tightening machine configured to stop the electric motor after releasing the biting on the second nut. 5. The nut tightening machine according to claim 4, wherein a current value detected by the motor controller can be changed according to a size of the second nut.

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