JP2019081213A - Impact rotary tool - Google Patents

Abstract

To provide a technique for improving control precision of fastening torque.SOLUTION: In an impact rotary tool 1, an impact mechanism 9 causes an output shaft 8 to generate intermittent rotary impact force with motor output. An impact detection part 12 comprises an impact detection part 12 which detects an impact applied to the output shaft 8 by the impact mechanism 9, and an impact monitor part 25 which monitors an output waveform of the impact detection part 12. The impact monitor part 25 specifies whether impact behavior by the impact mechanism 9 is proper from the output waveform of the impact detection part 12, and then specifies the kind of improper impact behavior.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an impact rotary tool for fastening a screw member such as a bolt or a nut by intermittent rotational impact force.

  The impact rotary tool clamps the screw member by the hammer rotating at the motor output intermittently hitting the anvil in the rotational direction. Since the impact rotary tool is used in an assembly plant or the like, the tightening torque of the screw member needs to be accurately controlled to be the value set by the user.

  In the impact rotary tool, since power is supplied by the rechargeable battery built into the battery pack, it is difficult to control the tightening torque with high accuracy if the motor rotation speed can not be maintained constant due to the battery voltage drop. Can be Therefore, Patent Document 1 discloses an impact rotary tool that limits the striking force when the battery voltage is high by PWM control, and controls the motor so as to maintain the striking force even when the battery voltage decreases.

International Publication No. 2015/133082

  The material and size of the screw member to be tightened are various in the tightening operation by the impact rotating tool, and various sockets are mounted on the output shaft depending on the screw member and the work environment. There are various types of sockets such as standard impact sockets, long extension sockets, and small diameter ball point bits, but the torsional rigidity of these sockets differs depending on the difference in shape, size, etc.

  In the impact rotary tool, when the hammer strikes the anvil, it retracts in a direction away from the anvil, and then, while rotating, advances by the spring biasing force to repeat the behavior of striking the anvil. This striking behavior is suitably repeated by setting the amount of retraction of the hammer to an appropriate value, and the condition for realizing high-precision torque control is thereby prepared. However, depending on the torsional rigidity generated by the combination of the spring member and the socket, the hammer retraction amount may deviate from the appropriate value, and in this case, an inappropriate striking behavior occurs, making it difficult to realize high-precision torque control. Can be

  The present invention has been made in view of these circumstances, and an object thereof is to provide a technique for specifying a striking behavior by an impact mechanism or a technique for adjusting a striking behavior by an impact mechanism.

  In order to solve the above problems, an impact rotary tool according to an aspect of the present invention detects an impact mechanism that generates an intermittent rotary impact force on an output shaft by a motor output, and detects an impact applied to an output shaft by the impact mechanism. And an impact monitoring unit monitoring an output waveform of the impact detecting unit. The impact monitoring unit determines whether or not the impact behavior by the impact mechanism is appropriate from the output waveform of the impact detecting unit. .

  Another aspect of the present invention is also an impact rotary tool. The impact rotary tool includes an impact mechanism that generates an intermittent rotary impact force on an output shaft by a motor output, an impact detection unit that detects an impact applied to the output shaft by the impact mechanism, and one impact of the impact mechanism. The rotation angle acquisition unit acquires the rotation angle of the output shaft, the energy calculation unit calculates the impact energy applied to the output shaft by one strike of the impact mechanism, and the impact energy and rotation angle acquired by the energy calculation unit A tightening torque calculation unit that calculates tightening torque based on the output shaft rotation angle acquired by the unit, a motor control unit that controls rotation of the motor based on the calculated tightening torque, and upper limit rotation of the motor by user operation And a setting unit that changes the number.

  According to the present invention, it is possible to provide a technique for specifying the impact behavior by the impact mechanism or a technique for adjusting the impact behavior by the impact mechanism.

It is a figure showing composition of an impact rotary tool concerning an embodiment. It is a figure which shows the example of the relationship between the amount of retractions of an operation switch, and a motor rotation speed. It is a figure which shows a mode that a hammer applies the striking of a rotation direction to an anvil. It is a figure for demonstrating the striking behavior by a hammer. It is a figure which shows an example of the output waveform of a striking detection part. It is a figure for demonstrating the 1st mode of an inadequate striking behavior. It is a figure for demonstrating the 2nd mode of an inadequate striking behavior. It is a figure for demonstrating the 3rd mode of an inadequate striking behavior. It is a figure for demonstrating the 4th mode of an inadequate striking behavior.

  FIG. 1 shows the configuration of an impact rotary tool according to an embodiment of the present invention. In the impact rotary tool 1, power is supplied by the battery 13 built in the battery pack. The motor drive circuit 11 mounts switching elements, such as FET (field effect type transistor) and IGBT (insulated gate type bipolar transistor), comprises an inverter circuit, and drives the motor 2 which is a drive source. The rotational output of the motor 2 is decelerated by the reducer 3 and transmitted to the drive shaft 5. A hammer 6 is connected to the drive shaft 5 via a cam mechanism (not shown), and the hammer 6 is biased by a spring 4 toward an anvil 7 provided with an output shaft 8. The output shaft 8 is fitted with a screw member to be tightened and a socket suitable for a working environment.

  While a load equal to or greater than a predetermined value is not applied between the hammer 6 and the anvil 7, the hammer 6 and the anvil 7 are engaged in the rotational direction, and the hammer 6 transmits the rotation of the drive shaft 5 to the anvil 7. However, when a load equal to or greater than a predetermined value acts between the hammer 6 and the anvil 7, the hammer 6 is retracted against the spring 4 by the cam mechanism, and the engagement between the hammer 6 and the anvil 7 is released. Thereafter, due to the biasing by the spring 4 and the guidance by the cam mechanism, the hammer 6 is advanced while rotating to apply a rotary striking to the anvil 7. In the impact rotary tool 1, the spring 4, the drive shaft 5, the hammer 6 and the cam mechanism apply a striking impact to the anvil 7 and the output shaft 8 by the motor output to intermittently rotate the anvil 7 and the output shaft 8. The impact mechanism 9 to generate is comprised.

  In the impact rotary tool 1, the configurations of the control unit 10, the setting unit 15 and the like are realized by a microcomputer or the like mounted on a control substrate. The control unit 10 includes a rotation angle acquisition unit 20, a rotation speed acquisition unit 21, an energy calculation unit 22, a tightening torque calculation unit 23, a motor control unit 24, and an impact monitoring unit 25, and calculates a tightening torque. It has a function of controlling the rotation of the motor 2 based on the calculated tightening torque.

  The operation switch 16 is a trigger switch that is pulled by the user. The motor control unit 24 controls the on / off of the motor 2 by the operation of the operation switch 16 and supplies the motor drive circuit 11 with a drive instruction to rotate the motor 2 at a rotational speed corresponding to the amount of retraction of the operation switch 16. The motor drive circuit 11 supplies a drive current to the stator winding of the motor 2 according to a drive instruction supplied from the motor control unit 24 to rotate the motor 2.

FIG. 2 shows an example of the relationship between the amount of retraction of the operation switch and the motor rotational speed. A play is set in the section of _{0 to} a ₀ lead-in amount. The section of a pull-in amount from a _{0 to} a ₁ is a low-speed rotation section, and the relationship is set such that the number of rotations increases as the pull-in amount increases. The motor control unit 24, the switch pull amount is a _0, and rotated at a rotational speed N ₀ as well as on the motor 2, as pull amount approaches a _1, adjusted to approximate the motor rotational speed N ₁ . Depending on the impact rotary tool 1, for example, a ₀ may be about 2 mm, and a ₁ may be about 5 mm.

a. The number of revolutions of the motor is set to the upper limit number of revolutions Nmax for _one or more lead-in amounts. In the tightening operation, the user maintains the state in which the operation switch 16 is pulled to the maximum retraction amount (> a ₁ ) until the motor 2 automatically stops. Therefore, the motor control unit 24 supplies a drive instruction to the motor drive circuit 11 such that the motor rotation speed becomes the upper limit rotation speed Nmax until the motor 2 is automatically stopped.

  In the impact rotary tool 1, the usable range is set to the battery voltage of the battery 13, and the motor control unit 24 determines the voltage drop abnormality and drives the motor when the battery voltage falls below the lower limit voltage of the usable range. To prohibit battery management. Under this battery management, the upper limit rotational speed Nmax may be set to a rotational speed that can be rotated at the lower limit voltage. By limiting the upper limit rotational speed Nmax to a low value in advance, the motor control unit 24 can always control the rotation of the motor 2 at the upper limit rotational speed Nmax within the usable range of the battery voltage. That is, the motor control unit 24 limits the striking force when the battery voltage is high by PWM control, and controls the motor 2 so that the striking force can be maintained constant even when the battery voltage decreases. The upper limit rotational speed Nmax may be set to a rotational speed that can be rotated at a voltage higher than the lower limit voltage.

  The impact detection unit 12 detects an impact applied to the anvil 7 and the output shaft 8 by the impact mechanism 9. For example, the impact detection unit 12 may include an impact sensor that detects an impact caused by the hammer 6 striking the anvil 7, and an amplifier that amplifies the output of the impact sensor and supplies the amplified output to the control unit 10. For example, the impact sensor is a piezoelectric shock sensor and outputs a voltage signal corresponding to the impact, and the amplifier amplifies the output voltage signal and supplies the amplified signal to the control unit 10. The impact detection unit 12 may adopt another configuration, and may be a sound sensor that detects an impact applied to the anvil 7 by the impact mechanism 9 by detecting an impact sound, for example.

  The rotation angle detection unit 18 detects the rotation angle of the motor 2. In the embodiment, the rotation angle detection unit 18 may be a magnetic rotary encoder that detects the rotation angle of the motor 2. The rotation angle detection unit 18 supplies a motor rotation angle detection signal to the rotation angle acquisition unit 20. In the embodiment, the rotation angle acquisition unit 20 has a function of acquiring the rotation angle of the output shaft 8 from the motor rotation angle detection signal. Here, the rotation angle acquisition unit 20 acquires an angle at which the output shaft 8 rotates for each impact by the impact mechanism 9. Hereinafter, the angle at which the output shaft 8 is rotated by one impact is simply referred to as “output shaft rotation angle”.

  FIGS. 3A to 3C show how the hammer 6 strikes the anvil 7 in the rotational direction. The hammer 6 has a pair of hammer claws 6a, 6b erected from the front surface, and the anvil 7 has a pair of anvil claws 7a, 7b extending radially from the central portion. The anvil 7 is integral with the output shaft 8, and the output shaft 8 rotates with the anvil 7.

FIG. 3A shows a state in which the hammer claws and the anvil claws are engaged in the circumferential direction. The hammer claws 6a and 6b engage with the anvil claws 7a and 7b, respectively, and apply a rotational force in the direction indicated by the arrow A.
FIG. 3B shows a state in which the engagement between the hammer claw and the anvil claw is released. When a load equal to or greater than a predetermined value is applied between the hammer 6 and the anvil 7 in the engaged state, the hammer 6 is retracted relative to the anvil 7 by a cam mechanism (not shown), and the engagement between the hammer claw 6a and the anvil claw 7a The engaged state and the engaged state between the hammer claw 6b and the anvil claw 7b are released.
FIG. 3C shows a state in which the hammer claw strikes the anvil claw to rotate the anvil 7. When the engagement between the hammer claws 6a and 6b and the anvil claws 7a and 7b is released, the hammer 6 advances while rotating in the direction indicated by the arrow A, and the hammer claws 6a and 6b are anvil claws 7b, respectively. Hit 7a. By this impact shock, the anvil 7 is rotated by an angle θ formed by l1 and l2, and at this time, the rotation angle of the hammer 6 becomes (π + θ).

FIG. 4A to FIG. 4D show a positional relationship in which the hammer 6 and the anvil 7 are schematically developed in the circumferential direction in order to explain the striking behavior by the hammer 6.
FIG. 4A shows a state in which the hammer claws 6a and 6b strike the anvil claws 7a and 7b, respectively. The hammer 6 is applied with rotational force in the direction indicated by the arrow A, and is applied with biasing force by the spring 4 in the forward direction (direction toward the anvil 7).

  When the hammer claws 6a and 6b strike the anvil claws 7a and 7b, they move away from the anvil claws 7a and 7b in the circumferential direction relatively while receiving the reaction force of the collision and moving backward by the cam mechanism (FIG. b) see). Thereafter, the hammer claws 6a and 6b move so as to get over the anvil claws 7a and 7b, respectively (see FIG. 4C), and the hammer 6 is rotated in the direction indicated by the arrow A by the biasing force of the compressed spring 4. Advance towards the anvil 7. Then, as shown in FIG. 4 (d), the hammer claws 6a, 6b strike the anvil claws 7b, 7a, respectively. The above operation is repeated at high speed during the tightening operation of the screw member, and the rotational impact force by the hammer 6 is repeatedly applied to the anvil 7.

The rotation angle acquisition unit 20 acquires the output shaft rotation angle θ per one impact using the detection result by the impact detection unit 12 and the detection result by the rotation angle detection unit 18. Specifically, the rotation angle acquisition unit 20 acquires the output shaft rotation angle θ by one impact from the motor rotation angle φ between impacts using the following (Expression 1). When the impact detection unit 12 detects an impact by the impact mechanism 9, the rotation angle acquisition unit 20 derives the output shaft rotation angle θ between impacts from the motor rotation angle detection signal at the timing when the impact is detected.
θ = (φ / η) −π (Equation 1)
Here, η indicates the reduction gear ratio by the reduction gear 3.

FIG. 5 shows an example of the output waveform of the impact detection unit 12. The impact monitoring unit 25 monitors the output waveform of the impact detection unit 12 which is a shock sensor. In the output waveform shown in FIG. 5, a pulse (hereinafter also referred to as a “striking pulse”) is generated at time t _n and t _{n + 1} , and the striking monitoring unit 25 detects the striking pulse. Informs that a strike has occurred. Thereby, the rotation angle acquisition unit 20 derives the output shaft rotation angle θ generated between the times t _n and t _{n + 1} .

The rotational speed acquisition unit 21 acquires an impact speed ω between impacts using the detection result by the impact detection unit 12, the detection result by the rotation angle detection unit 18, and information from a timer (not shown). The rotational speed acquisition unit 21 specifies the time between impacts from the timer output, and calculates the impact speed ω. When the moment of inertia of the anvil 7 and the output shaft 8 is J, the energy calculating unit 22 is applied to the anvil 7 and the output shaft 8 by one impact of the impact mechanism 9 using the following (Expression 2) The impact energy E is calculated.
E = (1/2) × J × ω ² (Equation 2)

The tightening torque calculation unit 23 calculates a tightening torque T based on the impact energy E calculated by the energy calculation unit 22 and the output shaft rotation angle θ acquired by the rotation angle acquisition unit 20 using Equation 3 below. Calculate
T = E / θ (Equation 3)
The motor control unit 24 controls the rotation of the motor 2 based on the tightening torque T calculated by the tightening torque calculation unit 23. Specifically, the motor control unit 24 automatically stops the rotation of the motor 2. Hereinafter, a control example of motor automatic stop will be described.

  The user sets a target tightening torque value (hereinafter, also simply referred to as “target torque value”) corresponding to the work target in the impact rotary tool 1 before the start of the work. The receiving unit 14 receives an operation input by the user and supplies the operation input to the setting unit 15. The reception unit 14 has a wireless communication module, and the user may use the remote controller attached to the tool to perform an operation input to the impact rotary tool 1. In the impact rotary tool 1 of the embodiment, the user can select one of 30 target torque values. The tool body may be provided with operation buttons and a touch panel, and the receiving unit 14 may receive an input of a target torque value from the user.

  When the receiving unit 14 receives the input of the target torque value, the setting unit 15 refers to the stored contents of the shutoff stroke number storage unit 17 and derives the shutoff stroke number and the predetermined torque value corresponding to the target torque value. , Set in the control unit 10. Setting of the shutoff stroke number that the setting unit 15 supplies the shutoff stroke number and a predetermined torque value to the control unit 10 and the control unit 10 makes the shutoff stroke number available for rotation control of the motor 2 It is called processing.

  The shutoff stroke number storage unit 17 stores, for each target torque value of 30 steps, the number of strokes from reaching the predetermined torque value to reaching the target torque value. The shutoff hit number storage unit 17 may be configured as a master table, and the stored content may not be updated.

  During work, the batt monitoring unit 25 monitors the output waveform of the batt detection unit 12, and when the output voltage of the batt detection unit 12 exceeds the batting determination voltage Vth, the occurrence of the batt by the impact mechanism 9 is determined. The impact monitoring unit 25 has a comparator that compares the output voltage of the impact detection unit 12 with the impact determination voltage Vth, and may determine from the output of the comparator that the output shaft 8 has been impacted.

  The motor control unit 24 controls the rotation of the motor 2 based on the tightening torque T calculated by the tightening torque calculation unit 23. Specifically, when the tightening torque T reaches a predetermined torque value, the motor control unit 24 counts the impacts determined by the impact monitoring unit 25, and when the counted impact number becomes the shutoff impact number Stop the rotation. By such motor control, the impact rotary tool 1 controls the tightening torque with high accuracy.

  Thus, the shutoff strike number is used to manage the tightening torque. The maker of the impact rotary tool 1 measures the number of shutoff impacts for realizing each of a plurality of tightening torque values using predetermined screw members and a socket, and creates a master table. Thus, the number of shutoff impacts corresponding to each tightening torque value actually measured under predetermined conditions is recorded on the master table.

  However, screw members and sockets to be actually worked may be different from the screw members and sockets at the time of creating the master table. For example, when the socket used when creating the master table is a standard impact socket, if the socket used in actual work is a long extension socket, the torsional rigidity of the socket itself will be greatly different. The rigidity also changes depending on the combination of the screw member and the socket. The impact behavior by the impact mechanism 9 is ideally that the hammer claws and the anvil claws collide in the tracks shown in FIGS. 4 (a) to 4 (d). The impact behavior may be inappropriate due to various factors such as. Therefore, in the impact rotary tool 1 of the embodiment, the impact monitoring unit 25 has a function of specifying whether or not the impact behavior by the impact mechanism 9 is appropriate from the output waveform of the impact detection unit 12.

Hereinafter, the type (mode) of the improper striking behavior will be described.
FIG. 6 (a) shows a first mode of improper striking behavior. In the first mode, after the hammer claw 6a strikes the anvil claw 7b, the hammer 6 is retracted to the maximum retracted position by the cam mechanism. As a result, the steel ball in the cam mechanism collides with the end of the cam groove, noise and vibration occur, and the cam mechanism may be broken. Factors that cause the first mode to occur include the lack of forward force by the spring 4 and the fact that the rotational speed of the hammer 6 is too high.

FIG. 6B shows an example of the output waveform of the batting detection unit 12 in the first mode. In the output waveform shown in FIG. 6 (b), the striking pulse at time t _n is one in which the striking of the anvil pawl 7b by the hammer pawl 6a in FIG. 6 (a) is detected. In the first mode, after the hammer claw 6a strikes the anvil claw 7b, when the hammer 6 is retracted to the maximum retracted position by the cam mechanism, the impact detection unit 12 has a time due to the collision of the steel ball and the cam groove end. The oscillating pulse 41 is output at time t _a closer to time t _n than the intermediate position between t _n and t _{n + 1} .

Striking monitoring unit 25 grasps the timing of striking pulses detected after the striking pulse of time t _n is around time t _{n + 1.} Therefore, referring to FIG. 5, when batting detection unit 12 outputs batting pulses at times t _n and t _{n + 1} , batting monitoring unit 25 specifies that the batting behavior by impact mechanism 9 is appropriate.

On the other hand, as shown in FIG. 6 (b), the oscillation pulse 41 from the striking detector 12 at time t _a is outputted, the striking monitoring unit 25, the striking behavior of the impact mechanism 9 is inappropriate Identify. Further, the batt monitoring unit 25 may specify the type of the batting behavior that is inappropriate according to the output waveform of the batt detection unit 12. Regarding the output waveform shown in FIG. 6 (b), the striking monitoring unit 25 specifies that the striking behavior in the first mode is generated by the interval between the striking pulse time t _n and the vibrating pulse 41 time t _a. You may

  FIG. 7A shows a second mode of improper striking behavior. In this second mode, after the hammer claw 6a strikes the anvil claw 7a, when it moves back to the anvil claw 7b once it has retreated, a deficiency in the amount of forward movement occurs. As a result, the hammer claw 6a can not strike the side surface of the anvil claw 7b, and operates so as to go to the next anvil claw 7a while rubbing the bottom surface of the anvil claw 7b. As a result, there is a possibility that the tightening torque is reduced, and the hammer claws and the anvil claws may be partially worn. Factors that cause the second mode include the lack of forward force by the spring 4 and the fact that the rotational speed of the hammer 6 is too high.

FIG. 7B shows an example of an output waveform of the batting detection unit 12 in the second mode. In the output waveform shown in FIG. 7 (b), the striking pulse at time t _n is one in which the striking of the anvil pawl 7a by the hammer pawl 6a in FIG. 7 (a) is detected. In the second mode, after the hammer claw 6a strikes the anvil claw 7a, the front surface of the hammer claw 6a comes in contact with the bottom surface of the anvil claw 7b, so that the batting detection unit 12 is closer to an intermediate position than time t _n and t _{n + 1.} The oscillation pulse 42 is output at time t _b close to time t _{n + 1} .

When oscillation pulse 42 from the striking detector 12 at time t _b is output, the striking monitoring unit 25 identifies that the striking behavior of the impact mechanism 9 is improper. Further, the impact monitoring unit 25 specifies that the impact behavior in the second mode is generated by the interval between the time t _n of the impact pulse and the time t _b of the vibration pulse 42 in the output waveform shown in FIG. You may

  The first mode and the second mode are generated due to the insufficient advancing force of the hammer 6 by the spring 4 and the rotational speed of the hammer 6 being too high. One practical way to eliminate this factor is to reduce the rotational speed of the hammer 6. By appropriately reducing the rotational speed of the hammer 6, the factors causing the first mode and the second mode can be eliminated, and the impact behavior by the impact mechanism 9 can be corrected.

  When the impact monitoring unit 25 identifies that the impact behavior is inappropriate, the display unit 30 displays the result of the identification by the impact monitoring unit 25. If the impact monitoring unit 25 specifies an inappropriate type of impact behavior, the display unit 30 displays information indicating the type of inappropriate impact behavior. As a result, the user recognizes that an inappropriate striking behavior is occurring, recognizes the type of improper striking behavior, and understands that the striking behavior becomes appropriate by appropriately reducing the rotational speed of the hammer 6 .

  The user uses the remote controller to perform operation input to lower the upper limit rotational speed Nmax of the motor 2. When the receiving unit 14 receives an operation input from the user, the setting unit 15 changes the upper limit rotational speed Nmax of the motor 2 to lower. As the setting unit 15 lowers the upper limit rotational speed Nmax, the motor control unit 24 reduces the rotational speed of the motor 2 more than when the first mode or the second mode is generated. Then, the user performs a tightening operation using the impact rotary tool 1 after the change of the upper limit rotational speed Nmax, and confirms whether or not the impact behavior is appropriate. When the information indicating the type of improper striking behavior is redisplayed on the display unit 30 during or after the operation, the user uses the remote controller to readjust the upper limit rotational speed Nmax. By performing the adjustment operation of the upper limit rotational speed Nmax until the error is not displayed on the display unit 30, the upper limit rotational speed Nmax optimal for the combination of the screw member and the socket is derived.

  In the case where the upper limit rotational speed Nmax is lowered, the impact energy by one impact decreases, and therefore, the user needs to set the number of shutoff impacts to a large number. In the impact rotary tool 1 of the embodiment, the number of shutoff hits is increased by the user selecting a target torque value higher than the target torque value before lowering the upper limit rotational speed Nmax among the target torque values of 30 steps. be able to. Therefore, when the user lowers the upper limit rotational speed Nmax, the impact rotary tool 1 can perform appropriate torque control by simultaneously setting the target torque value that determines the number of shutoff impacts high.

  FIG. 8A shows a third mode of improper striking behavior. In the third mode, after the hammer claw 6a strikes the anvil claw 7b, the amount of retraction is insufficient, so that the anvil claw 7b is struck again or the striking surface of the anvil claw 7b is rubbed up. As a result, there is a possibility that the tightening torque is reduced, and the hammer claws and the anvil claws may be partially worn. Factors that cause the third mode include the fact that the forward force by the spring 4 is too large, and the rotational speed of the hammer 6 is too small.

FIG. 8B shows an example of the output waveform of the batting detection unit 12 in the third mode. In the output waveform shown in FIG. 8 (b), the striking pulse at time t _{n + 1} is the one in which the first striking of the anvil pawl 7b by the hammer pawl 6a in FIG. 8 (a) is detected. In the third mode, after the hammer nail 6a strikes the anvil claw 7b, the side of the hammer nail 6a re-contacts (re-strikes) the side face of the anvil claw 7b, so that the batting detection unit 12 immediately after time t _{n + 1} . The vibration pulse 43 is output at time t _c .

When the vibration pulse 43 is output from the impact detection unit 12 at time t _c , the impact monitoring unit 25 identifies that the impact behavior by the impact mechanism 9 is inappropriate. Further, the impact monitoring unit 25 specifies that the impact behavior in the third mode is generated by the interval between the time t _{n + 1} of the impact pulse and the time t _c of the vibration pulse 43 in the output waveform shown in FIG. You may

  FIG. 9A shows a fourth mode of improper striking behavior. In the fourth mode, after the hammer claw 6a strikes the anvil claw 7a, the hammer claw 6a contacts the anvil 7 before striking the anvil claw 7b because the amount of advance is excessive. As a result, there is a possibility that the tightening torque is reduced, and the hammer and anvil claws may be worn out unevenly, and vibration and noise increase. Factors that cause the fourth mode include the fact that the forward force of the spring 4 is too large, and the rotational speed of the hammer 6 is too small.

FIG. 9B shows an example of the output waveform of the batting detection unit 12 in the fourth mode. In the output waveform shown in FIG. 9 (b), the striking pulse at time t _n is one in which the striking of the anvil pawl 7a by the hammer pawl 6a in FIG. 9 (a) is detected. In the fourth mode, after the hammer claw 6a strikes the anvil claw 7a, the front surface of the hammer claw 6a contacts (collides on) the surface of the anvil 7 so that the batting detection unit 12 detects the time t _d immediately before time t _{n + 1.} The vibration pulse 44 is output at

When oscillation pulse 44 at time t _d from the striking detector 12 is output, the striking monitoring unit 25 identifies that the striking behavior of the impact mechanism 9 is improper. Further, the impact monitoring unit 25 specifies that the impact behavior in the fourth mode is generated by the interval between the time t _n of the impact pulse and the time t _d of the vibration pulse 44 with respect to the output waveform shown in FIG. You may

  The third mode and the fourth mode are caused by the fact that the forward force of the hammer 6 by the spring 4 is too large and the rotational speed of the hammer 6 is too small. One practical way to eliminate this factor is to increase the rotational speed of the hammer 6. By appropriately increasing the rotational speed of the hammer 6, the causes of the third mode and the fourth mode can be eliminated, and the impact behavior by the impact mechanism 9 can be corrected.

  When the impact monitoring unit 25 identifies that the impact behavior is inappropriate, the display unit 30 displays the result of the identification by the impact monitoring unit 25. If the impact monitoring unit 25 specifies an inappropriate type of impact behavior, the display unit 30 displays information indicating the type of inappropriate impact behavior. As a result, the user recognizes that an inappropriate striking behavior is occurring, recognizes the type of improper striking behavior, and understands that the striking behavior becomes appropriate by appropriately increasing the rotational speed of the hammer 6 .

  The user uses the remote controller to perform an operation input to increase the upper limit rotational speed Nmax of the motor 2. When the receiving unit 14 receives an operation input from the user, the setting unit 15 changes the upper limit rotational speed Nmax of the motor 2 to increase. As the setting unit 15 raises the upper limit rotational speed Nmax, the motor control unit 24 increases the rotational speed of the motor 2 more than when the third mode or the fourth mode is generated. Then, the user performs a tightening operation using the impact rotary tool 1 after the change of the upper limit rotational speed Nmax, and confirms whether or not the impact behavior is appropriate. When the information indicating the type of improper striking behavior is redisplayed on the display unit 30 during or after the operation, the user uses the remote controller to readjust the upper limit rotational speed Nmax. By performing the adjustment operation of the upper limit rotational speed Nmax until the error is not displayed on the display unit 30, the upper limit rotational speed Nmax optimal for the combination of the screw member and the socket is derived.

  When the upper limit rotational speed Nmax is increased, the impact energy per impact increases, so the user needs to re-set the number of shutoff impacts smaller. When the user increases the upper limit rotational speed Nmax, the impact rotary tool 1 can perform appropriate torque control by simultaneously setting the target torque value that determines the number of shutoff impacts low.

  The present invention has been described above based on the embodiments. It is understood by those skilled in the art that this embodiment is an exemplification, and that various modifications can be made to their respective components or combinations of processing processes, and such modifications are also within the scope of the present invention. .

  In the embodiment, the impact monitoring unit 25 determines the appropriateness or inappropriateness of the striking behavior, and provides a trigger for the user to adjust the upper limit rotational speed Nmax of the motor 2 manually. The upper limit rotational speed Nmax can be freely changed according to the socket to be used and the operating environment.

  In the embodiment, it has been described that the user manually adjusts the upper limit rotational speed Nmax and the target torque value using the remote controller, but the setting unit 15 sets the upper limit rotational speed according to the type of improper striking behavior. Nmax and the target torque value may be adjusted automatically.

A summary of aspects of the invention is as follows.
An impact rotary tool (1) according to an aspect of the present invention has an output mechanism (9) for generating an intermittent rotary impact force on an output shaft (8) by a motor output, and an output mechanism (9) having an output mechanism (9). And an impact monitoring unit (25) for monitoring an output waveform of the impact detecting unit (12), the impact monitoring unit (25) including an impact detecting unit From the output waveform of (12), it is specified whether or not the impact behavior by the impact mechanism (9) is appropriate.

  The impact monitoring unit (25) may specify the type of improper striking behavior according to the output waveform of the impact detection unit (12). The impact rotary tool (1) may further include a display (30) that displays the result specified by the impact monitoring unit (25). The impact rotary tool (1) may further include a setting unit (15) configured to change the upper limit rotational speed of the motor (2) by a user operation.

  The impact rotary tool (1) includes a rotation angle acquisition unit (20) for acquiring an output shaft rotation angle by one impact of the impact mechanism (9), and an output shaft (8) by one impact of the impact mechanism (9). Tightening energy based on the striking energy calculated by the energy calculating unit (22) and the output shaft rotation angle acquired by the rotation angle acquiring unit (20). And a motor control unit (24) for controlling the rotation of the motor (2) based on the calculated tightening torque. The motor control unit (24) may limit the upper limit rotational speed of the motor (2) to a predetermined value.

  An impact rotary tool (1) according to another aspect of the present invention is provided with an impact mechanism (9) that generates intermittent rotational impact force on an output shaft (8) by a motor output, and an output shaft (8) by an impact mechanism (9). Of the impact mechanism (9), a rotation angle acquisition unit (20) for acquiring an output shaft rotation angle of a single impact of the impact mechanism (9), and an impact mechanism (9). An energy calculation unit (22) that calculates impact energy applied to the output shaft (8) by one impact, and an impact energy calculated by the energy calculation unit (22) and an output acquired by the rotation angle acquisition unit (20) A tightening torque calculation unit (23) that calculates a tightening torque based on the shaft rotation angle, a motor control unit (24) that controls the rotation of the motor (2) based on the calculated tightening torque, and user operation motor( ) Comprises setting unit for changing the upper limit rotation speed (15), the.

DESCRIPTION OF SYMBOLS 1 ... impact rotary tool, 2 ... motor, 6 ... hammer, 6a, 6b ... hammer claw, 7 ... anvil, 7a, 7b ... anvil claw, 8 ... output shaft 9, impact mechanism 10, control unit 11, motor drive circuit 12, striking detection unit 13, battery 14, reception unit 15, setting unit 16: Operation switch 17: shutoff number-of-hits storage unit 18: rotation angle detection unit 20: rotation angle acquisition unit 21: rotation speed acquisition unit 22 Energy calculation part, 23 ... tightening torque calculation part, 24 ... motor control part, 25 ... impact monitoring part, 30 ... display part.

Claims (6)

An impact mechanism that generates intermittent rotational striking force on the output shaft by motor output;
An impact detection unit that detects an impact applied to the output shaft by the impact mechanism;
And an impact monitoring unit that monitors an output waveform of the impact detection unit.
The impact monitoring unit specifies whether or not the impact behavior by the impact mechanism is appropriate from the output waveform of the impact detection unit.
Impact rotary tool characterized by The impact monitoring unit identifies the type of improper impact behavior according to the output waveform of the impact detection unit.
The impact rotary tool according to claim 1, characterized in that: The display device further comprises a display unit for displaying the result specified by the hit monitoring unit,
The impact rotary tool according to claim 1 or 2, characterized in that: The apparatus further comprises a setting unit that changes the upper limit rotational speed of the motor by user operation,
The impact rotary tool according to any one of claims 1 to 3, characterized in that: A rotation angle acquisition unit that acquires an output shaft rotation angle of a single impact of the impact mechanism;
An energy calculation unit that calculates impact energy applied to an output shaft by one impact of the impact mechanism;
A tightening torque calculation unit that calculates a tightening torque based on the impact energy calculated by the energy calculation unit and the output shaft rotation angle acquired by the rotation angle acquisition unit;
A motor control unit that controls the rotation of the motor based on the calculated tightening torque;
The motor control unit limits the upper limit rotational speed of the motor to a predetermined value.
The impact rotary tool according to any one of claims 1 to 4, characterized in that: An impact mechanism that generates intermittent rotational striking force on the output shaft by motor output;
An impact detection unit that detects an impact applied to the output shaft by the impact mechanism;
A rotation angle acquisition unit that acquires an output shaft rotation angle of a single impact of the impact mechanism;
An energy calculation unit that calculates impact energy applied to an output shaft by one impact of the impact mechanism;
A tightening torque calculation unit that calculates a tightening torque based on the impact energy calculated by the energy calculation unit and the output shaft rotation angle acquired by the rotation angle acquisition unit;
A motor control unit that controls the rotation of the motor based on the calculated tightening torque;
A setting unit configured to change the upper limit rotational speed of the motor by user operation;
Impact rotary tool characterized by

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