JP2016010832A - Nut fastening machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accelerate nut fastening work in a fastening tool for fastening a nut to a shear bolt in order to solve the problem in which different fastening machines were used for primary fastening and final fastening conventionally in a shear wrench for cutting a chip part and ensuring constant nut fastening torque, and as a result, the work was troublesome and took time.SOLUTION: A fastening machine for fastening a nut N to a torque shear bolt S while rotating an outer socket 18 by using an electric motor 2 as a driving force can be switched between a primary fastening mode for outputting high-speed low torque and a final fastening mode for outputting low-speed high torque by an operation of a mode changeover switch 40. The primary fastening and the final fastening can be performed by a single nut fastening machine 1, thereby achieving acceleration of the fastening work.

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. (Outer socket) and an inner socket that steps the tip of the shear bolt by rotating in the opposite direction to the outer socket with the tip (pin tail) of the shear bolt fitted in the inner periphery. Yes.

  At the beginning of the nut tightening (primary tightening stage), the outer socket rotates (rotates clockwise) in the nut tightening direction. The inner socket does not rotate during the primary 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 tightening stage, the shear bolt tip is sheared. 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, in the conventional primary tightening and the final tightening, two dedicated machines having different output torques are used properly, and there is a problem that the tightening work is troublesome and takes time. An object of the present invention is to speed up the primary fastening operation and the final fastening operation.

  The above-described problems are solved by the following inventions. A first invention is a tightening machine that rotates an outer sleeve by using an electric motor as a drive source and tightens a nut to a torque bolt, a primary tightening mode that outputs high speed and low torque, and a final tightening that outputs low speed and high torque. It is a nut tightening machine that can be switched between primary and final tightening modes.

  According to the first invention, both the primary tightening and the final tightening can be performed by switching the mode. Therefore, the primary tightening can be performed with a single nut tightening machine without preparing and replacing each dedicated machine as in the prior art. And the final tightening can be performed continuously, thereby speeding up the tightening operation of the nut.

  According to a second invention, in the first invention, the rotational output of the electric motor is decelerated through the planetary gear train and output to the outer socket for rotating the nut, and the internal gear of the planetary gear train is rotated. The nut tightening machine is configured to allow the primary tightening mode and restrict the rotation of the internal gear to the final tightening mode. According to the second aspect of the present invention, it is possible to reliably switch between the primary tightening mode and the final tightening mode by allowing the internal gear to rotate and restricting the rotation.

  A third invention is a nut tightening machine provided with a mode changeover switch in the second invention, wherein the internal gear is moved in the axial direction to switch between a state in which rotation is permitted and a state in which rotation is restricted. According to the third aspect of the present invention, the primary tightening mode and the final tightening mode can be switched by moving the internal gear by operating the mode switch.

  According to a fourth aspect of the present invention, there is provided the nut tightening machine according to the third aspect, wherein the operation state of the mode changeover switch is detected to discriminate between the primary tightening mode and the final tightening mode. According to the fourth invention, the operation state of the mode changeover switch is detected, and the operation control between the primary fastening mode and the final fastening mode is switched.

  According to a fifth invention, in any one of the first to fourth inventions, a motor control device that controls the operation of the electric motor is provided, and based on a change in the rotational speed of the electric motor detected by the motor control device. A nut tightening machine configured to automatically stop the electric motor. According to the fifth aspect of the invention, when the nut is tightened with an appropriate torque, the rotational speed of the electric motor decreases, and the change in the rotational speed is detected to automatically stop the electric motor. As a result, it is possible to save power by eliminating a useless starting state of the electric motor.

  A sixth invention is a nut fastening machine according to any one of the first to fifth inventions, comprising a bolt setting function for changing a rotational output of the electric motor in accordance with a size of a nut to be fastened. According to the sixth invention, since the electric motor operates with a rotation output appropriate for the size of the nut to be tightened (bolt size), the nut can be quickly tightened with an appropriate tightening torque without consuming unnecessary power. Can be done.

  A seventh invention is the nut tightening machine according to any one of the first to sixth inventions, wherein the electric motor is reversely rotated after the nut is tightened to remove the biting of the nut from the outer sleeve. According to the seventh aspect of the present invention, after the nut is tightened with an appropriate torque, the nut biting (galling) is automatically removed from the outer sleeve, and the nut tightening machine is quickly and easily detached from the Torcher bolt and tightened. The work can be finished.

It is a whole sectional view of a nut bolting machine concerning an embodiment of the present invention. This figure has shown the state switched to final fastening mode. It is a longitudinal cross-sectional view of the tool main-body part of the nut fastening machine which concerns on this embodiment. This figure has shown the state switched to the primary tightening mode. It is a longitudinal cross-sectional view of the front-end | tip part of a tool main body. This figure shows a state in which a nut is fitted in the outer socket, and a chip portion is fitted in the inner socket. It is a block diagram of a control device concerning this embodiment. It is a figure which shows the control flow which concerns on this embodiment. It is a figure which shows the control flow of a primary fastening mode. It is a figure which shows the control flow of the final fastening mode of a motor automatic stop type. It is a figure which shows the control flow of the final fastening mode of a motor manual stop type.

  Next, an embodiment of the present invention will be described with reference to FIGS. FIG. 1 shows a nut tightening machine 1 according to this embodiment. In the present embodiment, a so-called shear wrench is illustrated as an example of the nut tightening machine 1. The nut tightening machine 1 is used to tighten a nut N (for example, a hexagonal nut) to a so-called shear bolt S, and the chip portion Sa is cut (sheared). 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. A bearing 15 is interposed between the front case 17 and the third stage carrier 13a. Through the bearing 15, the front case 17 and the outer sleeve 16, the third stage carrier 13 a and the inner sleeve 14 are supported so as to be rotatable around the machine axis J. 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. A nut fitting portion 18 a into which the nut N 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. Another compatible outer socket can be attached to the outer sleeve 16. Four engaging recesses are provided on the rear outer peripheral surface of the outer socket 18. On the other hand, four engaging protrusions are provided on the outer peripheral surface of the front portion of the outer sleeve 16. The four engaging recesses and the four engaging protrusions are respectively provided in the circumferentially divided position. By inserting the rear side of the outer socket 18 into the inner peripheral side of the outer sleeve 16 and attaching the engagement protrusions into the respective engagement recesses, the outer socket 18 is attached to the outer sleeve 16. It becomes 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, unless the tip portion Sa is completely fitted to the tip fitting portion 19a of the inner socket 19, a nut cannot be fitted to the nut fitting portion 18a of the outer socket 18, Thereby, the licking with respect to the chip | tip part 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 fitting portion 19a of the inner socket 19 with respect to the shear bolt S in which the nut N is primarily tightened as shown in FIG. Insert into. 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 nut N is fitted into the nut fitting portion 18a of the outer socket 18, as shown in FIG. At this stage, the inner socket 19 is splined to the inner sleeve 14. When the switch lever 3 is turned on in this state to activate the electric motor 2, the outer socket 18 rotates and the nut N is tightened to the shear bolt S.

  When the tightening of the nut 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 reverse direction. Rotates in the opposite direction to the tightening direction of the nut. 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.

  The nut tightening machine 1 according to the present embodiment includes a speed change mechanism. A second-stage internal gear 12a of the second-stage planetary gear train 12 is provided so as to be displaceable in the axis J direction. A support sleeve 13 e is integrally provided on the third stage carrier 13 a of the third stage planetary gear train 13. A brake 41 is provided between the rear end portion of the support sleeve 13e and the main body case 9 to give a certain rotational resistance. The third-stage carrier 13a is in a state in which the third-stage carrier 13a cannot move in the machine axis J direction with respect to the main body case 9 and is given a certain rotational resistance around the machine axis J via the support sleeve 13e.

  As shown in FIG. 1, in a state where the second stage internal gear 12a is located on the front side, the meshing part 12aa provided on the front surface of the second stage internal gear 12a and the meshing part provided on the rear surface of the third stage carrier 13a. The second stage internal gear 12a is integrated with the third stage carrier 13a with respect to the rotation around the axis J by meshing 13aa with each other. For this reason, the second stage internal gear 12a is in a state in which a constant rotational resistance is applied around the axis J.

  On the other hand, as shown in FIG. 2, in the state where the second stage internal gear 12a is located on the rear side, the meshing part 12aa and the meshing part 13aa are disengaged and the second stage internal gear 12a is rotated. It will be in the state separated from the 3rd stage carrier 13a. For this reason, the second-stage internal gear 12a can rotate around the axis J. Further, in the case of the second embodiment, a meshing portion 11aa is provided around the first stage carrier 11a of the first stage planetary gear train 11. In a state where the second-stage internal gear 12a is located on the rear side, the meshing portion 11aa of the first-stage carrier 11a is engaged with the inner peripheral side thereof. Therefore, in this state, the first stage carrier 11a and the second stage internal gear 12a are integrated with respect to rotation.

  On the outer peripheral surface of the second-stage internal gear 12a, an engaging groove portion 12ab is provided over the entire periphery. The engagement edge portion 40a of the mode changeover switch 40 is inserted into the engagement groove portion 12ab. The engagement edge portion 40a enters the engagement groove portion 12ab as long as the rotation of the second-stage internal gear 12a is not hindered. The mode changeover switch 40 is an operation member having a cylindrical shape, and is fitted along the outer surface of the tool body 10. The mode changeover switch 40 is supported so as to be slidable within a certain range before and after. As shown in FIG. 1, when the mode changeover switch 40 is slid forward, the reduction ratio by the first to third stage planetary gear trains 11 to 13 is increased, and low speed and high torque is output to the outer socket 18. It becomes a state. On the contrary, when the mode changeover switch 40 is slid backward as shown in FIG. 2, the reduction ratio by the first to third stage planetary gear trains 11 to 13 becomes small, and the high speed and low torque is applied to the outer socket 18. Is output.

  As described above, when the mode changeover switch 40 is slid to the front side to switch to the low speed and high torque output state, the second stage internal gear 12a is displaced to the front side, and the meshing part 12aa becomes the meshing part of the third stage carrier 13a. By meshing with 13aa, the rotation of the second-stage internal gear 12a is locked. In this state, the second stage planetary gears 12b to 12b revolve and the third stage sun gear 13c rotates integrally with the second stage carrier 12d, whereby the third stage planetary gears 13d to 13d revolve while rotating. As a result, the front case 17 rotates about the axis J. As the front case 17 rotates about the axis J, the outer sleeve 16 rotates, and thus the outer socket 18 rotates at a relatively low speed. As the outer socket 18 rotates at a low speed, the nut N is securely fastened to the shear bolt S with high torque.

  When the nut N is tightened with high torque, the third-stage carrier 13a rotates in the opposite direction to the third-stage internal gear 13b by the reaction torque (tightening reaction force). The third stage carrier 13a is rotated against the rotational resistance of the brake 41 described above. When the third stage carrier 13a rotates in the reverse direction with the reaction torque at the time of tightening, the inner socket 19 rotates in the reverse direction via the inner sleeve 14, thereby shearing the tip portion Sa. Thus, the tip portion Sa is sheared and the reaction torque is absorbed, so that the reaction received by the user when tightening the nut is greatly reduced.

  As shown in FIG. 2, when the mode changeover switch 40 is slid backward to switch to the high speed low torque output state, the second stage internal gear 12a is disconnected from the third stage carrier 13a, while the first stage carrier 11a. Is engaged with the meshing portion 11aa. In this state, the first stage carrier 11a and the second stage internal gear 12a rotate together. For this reason, the reduction ratio of the second and third stage planetary gear trains 12 and 13 is reduced, and high speed and low torque is output to the outer socket 18. By outputting a high speed and low torque to the outer socket 18, the nut N is quickly fastened to the shear bolt S with a relatively small tightening torque. In this way, by the switching operation of the mode changeover switch 40, the reduction ratio by the first to third stage planetary gear trains 11 to 13 is changed, and the rotation output to the outer socket 18 is changed to the low speed and high torque output state (final tightening mode). It is possible to switch to a high speed low torque output state (primary tightening mode).

  The operation state of the mode switch 40 is detected by the mode switch sensor 42. The mode switching sensor 42 is accommodated in a sensor accommodating portion 9 a provided on the upper surface of the main body case 9. A detection rod 42 a is disposed between the mode switch 40 and the mode switch sensor 42. The detection rod 42a is supported so as to be displaceable back and forth. The front end of the detection rod 42 a is directed to the rear surface of the mode switch 40. The rear end of the detection rod 42 a is directed to the detection lever 42 b of the mode switching sensor 42. As shown in FIG. 1, when the mode changeover switch 40 is slid to the front side and switched to the low speed and high torque output state, the detection rod 42a can be displaced to the front side. As a result, the detection lever 42b of the mode changeover sensor 42 has a spring. The mode switching sensor 42 is turned off by returning to the off side by the force.

  On the other hand, as shown in FIG. 2, when the mode changeover switch 40 is slid back and switched to the high speed and low torque output state, the detection rod 42 a is pushed backward by the mode changeover switch 40. When the detection rod 42a is pushed rearward, the detection lever 42b of the mode switching sensor 42 is pushed to the on side by the rear end portion, and the mode switching sensor 42 is turned on. The on / off signal of the mode switching sensor 42 is input to a motor controller 51 of a motor control device 50 described later.

  The rotation speed of the electric motor 2 is detected by a rotation speed detection sensor 43. A magnet 45 is attached to the lower end of the output shaft 2 b of the electric motor 2. The rotational speed of the electric motor 2 is detected by detecting the rotational speed of the magnet 45 by the rotational speed detection sensor 43. The rotational speed information of the electric motor 2 is input to a motor controller 51 of a motor control device 50 described later. Based on the change in the rotation speed of the electric motor 2, it is confirmed that the nut N is tightened with a constant torque.

  In the nut tightening machine 1 of the present embodiment, the power (current or voltage) supplied to the electric motor 2 can be adjusted in accordance with the size of the nut N to be tightened (screw diameter of the Torcher bolt S). An adjustment dial 44 for adjusting the power supplied to the electric motor 2 is disposed on the lower side surface of the handle portion 30. On the adjustment dial 44, screw diameters “M16”, “M20”, and “M22” are displayed. The user can appropriately adjust the power supplied to the electric motor 2 according to the screw diameter by rotating the adjustment dial 44 while viewing the screw diameter display.

  The motor controller 50 controls the operation of the electric motor 2 based on output signals from the mode switching sensor 42, the rotation speed detection sensor 43, and the adjustment dial 44. An outline of the motor control device 50 according to the present embodiment is shown in FIG. 5 to 8 show flowcharts of operation control performed by the motor control device 50. The motor control device 50 includes a motor controller 51 including a CPU (Central Processing Unit). The motor controller 51 receives an output signal (mode switching signal) of the mode switching sensor 42, an ON signal of the main switch 4, an output signal of the adjustment dial 44, and rotation speed information of the electric motor 2.

  As shown in FIG. 5, when the main switch 4 is turned on, an on signal is input to the motor controller 51 (step 01, hereinafter abbreviated as “ST01”). When the ON signal of the main switch 4 is input, the mode changeover switch 40 is confirmed (ST02). If it is confirmed in ST03 that the mode is not the primary tightening mode, it is confirmed in ST04 whether or not the mode is the main tightening mode. If it is not in the final tightening mode, the mode changeover switch 40 is continuously checked in ST02. When it is confirmed that the final tightening mode is selected in ST04, the process proceeds to the final tightening mode (ST05). The final tightening mode shown in FIG. 7 or 8 will be described later.

  If it is confirmed in ST03 that the mode is the primary tightening mode, the mode is shifted to the primary tightening mode (ST06). As shown in FIG. 6, when the flow of the primary 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 44. By reading the screw diameter information and the operation state (primary tightening mode) of the mode changeover switch 40, the set value of the primary tightening torque suitable for the screw diameter is determined.

  Next, in ST09, a signal for starting the electric motor 2 is output to the motor drive 52, and the electric motor 2 is started at high speed and low torque for primary fastening. As the electric motor 2 starts, the outer socket 18 rotates at a high speed in the tightening direction (clockwise), and the nut N is tightened to the shear bolt S. In this process, the rotation speed of the electric motor 2 is monitored (ST10). In ST11, it is determined whether or not the rotational speed of the electric motor 2 has changed. If no change in the rotational speed of the electric motor 2 is confirmed, the motor rotational speed is continuously monitored in ST10.

  When the nut N is tightened with respect to the shear bolt S with a relatively low primary tightening torque, the rotation of the outer socket 18 is restricted. In addition, since the electric motor 2 is started at a low torque, the reaction torque of the outer socket 18 is small, so that the inner socket 19 does not reverse and therefore the tip portion Sa is not sheared. When both the outer socket 18 and the inner socket 19 do not rotate, the electric motor 2 is locked and the number of rotations changes.

  When a change in the motor rotation speed is confirmed in ST11, the electric motor 2 is temporarily stopped in ST12, and tightening of the outer socket 18 with respect to the nut N is stopped. Immediately after the electric motor 2 is temporarily stopped in this way, the electric motor 2 is restarted by a slight angle in the reverse direction in ST13. In this way, the electric motor 2 is rotated by a slight angle in the direction opposite to the tightening direction of the nut N, so that the outer socket 18 bites (gallings) against the nut N is released. By releasing the biting of the outer socket 18 with respect to the nut N, the outer socket 18 can be easily detached from the nut N, whereby the user finishes the work by moving the nut tightening machine 1 away from the tightening portion. can do. After the bite of the nut N is released in ST13, the electric motor 2 is automatically stopped in ST14. This completes the primary tightening mode routine. After completion of the primary tightening, the nut tightening machine 1 is once removed from the nut N and its tightening site.

  Next, when the nut N that has been primarily tightened as described above is finally tightened, the mode changeover switch 40 of the nut tightening machine 1 is slid forward to change the operation mode of the nut tightening machine 1 to the primary tightening mode. Switch to final tightening mode. When the mode change switch 40 is slid forward, the mode change sensor 42 is turned off. After switching to the final tightening mode, when the nut N is fitted into the nut fitting portion 18a of the outer socket 18 and the switch lever 3 is pulled (ST01), the off signal of the mode switching sensor 42 is input (the on signal is (Not input) As a result ST04, it is confirmed that it is the final fastening mode.

  If it is confirmed that the final tightening mode is selected in ST04, the process proceeds to the final tightening mode in ST05. As shown in FIG. 7, when the final tightening mode is started in ST15, since the mode changeover switch 40 is switched to the front side, the electric motor 2 is started at low speed and high torque (ST16). When the electric motor 2 is started, the outer socket 18 rotates in the nut tightening direction, and the nut N is finally tightened to the shear bolt S with high torque. In the process of tightening the nut N, the motor speed is monitored in ST17.

  When the nut N is finally tightened with a constant 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 nut N is properly managed, and the reaction torque generated by the tightening is absorbed. When the tip portion Sa is sheared, the inner sleeve 19 rotates idle (no load state). For this reason, the load of the electric motor 2 becomes small and the rotation speed changes. When a change in the motor rotational speed is confirmed in ST18, the electric motor 2 is automatically stopped in ST19. This completes the routine of the motor automatic stop type final fastening mode.

  In the above-described automatic motor stop type final tightening mode, even if the switch lever 3 is pulled and operated after the final tightening of the nut N is maintained, the electric motor 2 is automatically stopped and wasteful power consumption is consumed. It is suppressed. On the other hand, as described above, in the final tightening mode, when the nut N is finally tightened with a constant torque, the tip portion Sa is sheared and the inner socket 19 is idled. For this reason, as long as the switch lever 3 is pulled, even if the starting state of the electric motor 2 is maintained, problems such as burn-in do not occur. Therefore, instead of the motor automatic stop type, a motor manual stop type final tightening mode may be employed. FIG. 8 shows a flow of the motor manual stop type final fastening mode.

  When the switch lever 3 is pulled after the mode changeover switch 40 is slid forward to switch to the final tightening mode, the process shifts to the final tightening mode in ST05 shown in FIG. When the motor manual stop type final tightening mode is started in ST20 shown in FIG. 8, the electric motor 2 is started at low speed and high torque in ST21. When the electric motor 2 is started, the outer socket 18 rotates in the tightening direction, and the nut N is tightened to the shear bolt S. When the nut N is tightened with a constant final tightening torque, the inner socket 19 is reversed by the reaction torque to shear the tip portion Sa. During this time, instead of monitoring the rotational speed of the electric motor 2, the on / off state of the main switch 4 is monitored in ST22. Unless the OFF state of the main switch 4 is confirmed in ST23, the process returns to ST22 and the starting state of the electric motor 2 is maintained.

  When it is confirmed in ST23 that the main switch 4 is turned off, the electric motor 2 is stopped in ST24. Thus, in the motor manual stop type final tightening mode, after the nut N is tightened with the final tightening torque and the tip portion Sa is sheared, the electric motor 2 is maintained in the activated state when the switch lever 3 is in the ON operation state. When the switch lever 3 is turned off, the electric motor 2 is manually stopped. As described above, in the automatic stop type final tightening mode, when the nut N is finally tightened with an appropriate torque and the shearing of the tip portion Sa is completed, the motor is operated even if the switch lever 3 remains on. The motor 2 is automatically stopped. For this reason, the tightening operation can be completed quickly, and unnecessary power consumption is suppressed.

  As described above, according to the nut tightening machine 1 of the present embodiment, the reduction gear train composed of the first to third stage planetary gear trains 11 to 13 is operated by sliding the mode changeover switch 40 back and forth. By switching the reduction ratio, it is possible to switch between a state of outputting high speed and low torque to the outer socket 18 and a state of outputting low speed and high torque. Therefore, according to the nut tightening machine 1 of the present embodiment, it is possible to perform both the primary tightening at the initial stage for tightening the nut N against the shear bolt S and the final tightening at the final stage (primary tightening, final tightening). Combined machine). Since both the primary tightening and the final tightening can be performed by using one nut tightening machine 1, the tightening operation of the nut N can be speeded up compared to the case where the dedicated tightening machine is replaced and used. Can do.

  Further, according to the illustrated nut tightening machine 1, the adjustment dial 44 can set the output of the electric motor 2 according to the screw diameter of the nut N to be tightened, and this point also increases the versatility of the nut tightening machine 1. be able to.

  Further, in the primary tightening mode and the automatic stop type final tightening mode, the electric motor 2 is automatically stopped based on the change in the number of revolutions, so that the user immediately confirms that the nut N has been tightened with a constant torque. Thus, it is possible to speed up the tightening operation. Moreover, since the electric motor 2 is automatically stopped, wasteful power consumption can be suppressed. This point has a great effect in the case of a DC machine (battery specification nut tightening machine) that uses a battery as a power source instead of an AC machine (AC power supply specification nut fastening machine) exemplified as a power source.

  Various modifications can be made to the embodiment described above. For example, although the configuration in which the electric motor 2 is automatically stopped based on a change in the rotation speed of the electric motor 2 is illustrated, the electric motor 2 is automatically turned on based on a change in the current or voltage of the electric motor 2 (load fluctuation) It is good also as a structure to stop.

  In addition, the operation of releasing the biting of the nut N is included only in the primary fastening mode. However, the electric motor 2 is stopped in the final fastening mode and then reversely rotated to release the biting of the outer socket 18 against the nut N. Also good.

S ... Torscher Bolt (Sherbolt)
Sa ... Tip N ... Nut (Hex Nut)
1 ... Nut tightening machine (shear wrench)
2 ... Electric motor 2a ... Pinion gear, 2b ... Output shaft, 2c ... Rotor, 2d ... Stator, 2e ... Motor case 3 ... Switch lever 4 ... Main switch 5, 6 ... Intermediate gear 7 ... Intermediate shaft, 7a ... Bevel gear DESCRIPTION OF SYMBOLS 8 ... Bevel gear, 8a, 8b ... Bearing, 8c ... 1st stage sun gear 9 ... Main body case, 9a ... Sensor accommodating part 10 ... Tool body part, J ... Axle 11 ... 1st stage planetary gear train 11a ... 1st stage carrier 11a ... meshing portion, 11b ... first stage planetary gear 11c ... first stage internal gear 12 ... second stage planetary gear train 12a ... second stage internal gear, 12aa ... meshing portion, 12ab ... engagement groove 12b ... 2nd stage planetary gear, 12c ... 2nd stage sun gear, 12d ... 2nd stage carrier 13 ... 3rd stage planetary gear train 13a ... 3rd stage carrier, 13aa ... meshing part, 13b ... 3rd stage internal gear 13c ... third stage sun gear, 13d ... third stage planetary gear, 13e ... support sleeve 14 ... inner sleeve 15 ... bearing 16 ... outer sleeve 17 ... front case 18 ... outer socket, 18a ... nut fitting part 19 ... inner socket, 19a ... chip fitting portion 20 ... motor portion 30 ... handle portion 31 ... power cord 32 ... compression spring 33 ... stopper 34 ... compression spring 35 ... discharge lever 36 ... extrusion pin 37 ... slick prevention pin 40 ... mode changeover switch 40a ... engagement edge 41 ... brake 42 ... mode switching sensor 42a ... detection rod 42b ... detection lever 43 ... rotation speed detection sensor 44 ... adjustment dial 45 ... magnet 50 ... motor controller 51 ... motor controller 52 ... motor drive

Claims (7)

A tightening machine that rotates an outer sleeve using an electric motor as a drive source to tighten a nut on a Torcher bolt,
A nut tightening machine that can switch between the primary tightening mode that outputs high speed and low torque and the main tightening mode that outputs low speed and high torque. The nut tightening machine according to claim 1, wherein the rotational output of the electric motor is decelerated through a planetary gear train and output to an outer socket that rotates the nut, and the internal gear of the planetary gear train. A nut tightening machine configured to be in the primary tightening mode while allowing the rotation of the internal gear and to be in the final tightening mode by restricting the rotation of the internal gear. 3. The nut tightening machine according to claim 2, further comprising a mode changeover switch for switching the internal gear to a state allowing the rotation and a state restricting the rotation by moving the internal gear in the axial direction. The nut tightening machine according to claim 3, wherein the nut tightening machine detects an operation state of the mode changeover switch and discriminates between the primary tightening mode and the main tightening mode. The nut tightening machine according to any one of claims 1 to 4, comprising a motor control device that controls the operation of the electric motor, and a change in the rotational speed of the electric motor detected by the motor control device. A nut tightening machine configured to automatically stop the electric motor based on the above. The nut tightening machine according to any one of claims 1 to 5, comprising a bolt setting function for changing a rotational output of the electric motor in accordance with a size of a nut to be tightened. The nut tightening machine according to any one of claims 1 to 6, wherein the electric motor is reversely rotated after the nut is tightened to remove the biting of the nut against the outer sleeve.

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