JP6913870B2 - Impact rotary tool - Google Patents

Description

The present invention relates to an impact rotary tool that tightens a screw member such as a bolt or a nut by an intermittent rotary striking force.

In the impact rotary tool, the hammer that rotates with the motor output intermittently hits the anvil in the direction of rotation to tighten the screw member. Since the impact rotary tool is used in an assembly factory or the like, the tightening torque of the screw member needs to be accurately controlled so as to be a value set by the user.

With impact rotary tools, power is supplied by the rechargeable battery built into the battery pack, so if the motor rotation speed cannot be maintained constant due to a drop in battery voltage, it will be difficult to control the tightening torque with high accuracy. May become. 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 drops.

International Publication No. 2015/133082

In the tightening work with the impact rotary tool, the material and size of the screw member to be tightened are various, and the socket mounted on the output shaft is also various depending on the screw member and the working environment. There are various types of sockets used, 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 shape, size, and the like.

In the impact rotary tool, when the hammer hits the anvil, it retreats once in the direction away from the anvil, and then moves forward by the spring-forced force while rotating and repeats the behavior of hitting the anvil. This striking behavior is suitably repeated when the amount of retreat of the hammer takes an appropriate value, whereby a state for realizing highly accurate torque control is prepared. However, depending on the torsional rigidity generated by the combination of the spring member and the socket, the hammer retreat amount may deviate from the appropriate value. In this case, improper striking behavior occurs, making it difficult to realize highly accurate torque control. May become.

The present invention has been made in view of such a situation, and an object of the present invention 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, the impact rotary tool of an aspect of the present invention detects an impact mechanism that generates an intermittent rotary impact force on the output shaft by the motor output and an impact mechanism applied to the output shaft by the impact mechanism. It is provided with a striking detection unit and a striking monitoring unit that monitors the output waveform of the striking detection unit, and the striking monitoring unit identifies whether or not the striking behavior by the impact mechanism is appropriate from the output waveform of the striking detection unit. ..

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

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

It is a figure which shows the structure of the impact rotary tool which concerns on embodiment. It is a figure which shows the example of the relationship between the pull-in amount of an operation switch, and the motor rotation speed. It is a figure which shows how a hammer hits an anvil in the direction of rotation. 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 the impact detection part. It is a figure for demonstrating the 1st mode of improper batting behavior. It is a figure for demonstrating the 2nd mode of improper batting behavior. It is a figure for demonstrating the 3rd mode of improper batting behavior. It is a figure for demonstrating the 4th mode of improper batting 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, electric power is supplied by the battery 13 built in the battery pack. The motor drive circuit 11 is equipped with switching elements such as FETs (field effect transistors) and IGBTs (insulated gate bipolar transistors) to form an inverter circuit, and drives the motor 2 as a drive source. The rotational output of the motor 2 is decelerated by the speed 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 urged by a spring 4 toward the anvil 7 having the output shaft 8. The output shaft 8 is equipped with a screw member to be tightened and a socket suitable for the working environment.

While a load equal to or greater than a predetermined value does not act 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 retracts against the spring 4 by the cam mechanism, and the engagement state between the hammer 6 and the anvil 7 is released. After that, the hammer 6 advances while rotating by the urging by the spring 4 and the guidance by the cam mechanism, and hits the anvil 7 in the rotational direction. 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 apply an intermittent rotational striking force to the anvil 7 and the output shaft 8. It constitutes an impact mechanism 9 to generate.

In the impact rotary tool 1, the configuration of the control unit 10, the setting unit 15, and the like is realized by a microcomputer or the like mounted on the control board. The control unit 10 has 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 a impact monitoring unit 25, and calculates the 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 and operated by the user. The motor control unit 24 controls the on / off of the motor 2 by operating the operation switch 16, and supplies the motor drive circuit 11 with a drive instruction to rotate the motor 2 at a rotation speed corresponding to the pull-in amount of the operation switch 16. The motor drive circuit 11 supplies a drive current to the stator windings 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 pull-in amount of the operation switch and the motor rotation speed. A play is set in the section of the pull-in amount of _{0 to a 0.} The section of the pull-in amount from a _{0 to} a ₁ is a low-speed rotation section, and the relationship is set so that the rotation speed increases as the pull-in amount increases. When the switch pull-in amount reaches a ₀ , the motor control unit 24 turns on the motor 2 and rotates it at a rotation _{speed N 0} , and adjusts the motor rotation speed to approach N _{1 as the pull-in amount approaches a 1.} .. Although it depends on the impact rotary tool 1, for example, a ₀ may be about 2 mm and a ₁ may be about 5 mm.

against a ₁ or more pull amount, the motor rotational speed is set to the upper limit rotation speed Nmax. In the tightening operation, the user maintains the state in which the operation switch 16 is pulled to the maximum pull-in amount (> a _{1) until the motor 2 is automatically stopped.} Therefore, the motor control unit 24 supplies a drive instruction to the motor drive circuit 11 so that the motor rotation speed reaches the upper limit rotation speed Nmax until the motor 2 is automatically stopped.

In the impact rotary tool 1, a usable range is set for the battery voltage of the battery 13, and when the battery voltage falls below the lower limit voltage of the usable range, the motor control unit 24 determines a voltage drop abnormality and drives the motor. Battery management is performed. Under this battery management, the upper limit rotation speed Nmax may be set to the rotation speed that can be rotated at the lower limit voltage. By limiting the upper limit rotation 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 rotation 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 drops. The upper limit rotation speed Nmax may be set to a rotation speed that can be rotated at a voltage higher than the lower limit voltage.

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

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 the 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 the angle at which the output shaft 8 rotates for each hit by the impact mechanism 9. Hereinafter, the angle at which the output shaft 8 is rotated by one impact is simply referred to as an “output shaft rotation angle”.

3 (a) to 3 (c) show how the hammer 6 hits the anvil 7 in the rotational direction. The hammer 6 has a pair of hammer claws 6a and 6b erected from the front surface, and the anvil 7 has a pair of anvil claws 7a and 7b extending in the radial direction from the central portion. The anvil 7 is integrated with the output shaft 8, and the output shaft 8 rotates together with the anvil 7.

FIG. 3A shows a state in which the hammer claw and the anvil claw 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 hammer claw and the anvil claw are disengaged from each other. When a load exceeding a predetermined value acts between the hammer 6 and the anvil 7 in the engaged state, the hammer 6 retracts with respect to the anvil 7 by a cam mechanism (not shown), and the hammer claw 6a and the anvil claw 7a are engaged with each other. The combined 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 hits the anvil claw and rotates the anvil 7. When the engagement state 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 move forward with the anvil claws 7b and 7b, respectively. Hit 7a. Due to this impact, the anvil 7 rotates by the angle θ formed by l1 and l2, and at this time, the rotation angle of the hammer 6 becomes (π + θ).

4 (a) to 4 (d) show the 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 of the hammer 6.
FIG. 4A shows a state when the hammer claws 6a and 6b hit the anvil claws 7a and 7b, respectively. A rotational force is applied to the hammer 6 in the direction indicated by the arrow A, and a urging force is applied by the spring 4 in the forward direction (direction toward the anvil 7).

When the hammer claws 6a and 6b hit the anvil claws 7a and 7b, they move in a direction relatively away from the anvil claws 7a and 7b in the circumferential direction while retreating by the cam mechanism in response to the reaction force of the collision (FIG. 4 (FIG. 4). b) See). After that, 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 rotates in the direction indicated by the arrow A while being compressed by the urging force of the spring 4. Advance towards Anvil 7. Then, as shown in FIG. 4D, the hammer claws 6a and 6b hit the anvil claws 7b and 7a, respectively. During the tightening work of the screw member, the above operation is repeated at high speed, and the rotational striking 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 impact by 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 by using the following (Equation 1). When the impact detection unit 12 detects the impact by the impact mechanism 9, the rotation angle acquisition unit 20 derives the output shaft rotation angle θ between the 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 ratio by the speed reducer 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 due to impact (hereinafter, also referred to as “impact pulse”) is generated at _{time t n} and t _{n + 1, and when the impact monitoring unit 25 detects the impact pulse, the rotation angle acquisition unit 20} Notify that a blow has occurred. As a result, the rotation angle acquisition unit 20 derives the output shaft rotation angle θ generated during _{the time t n} and t _{n + 1.}

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

The tightening torque calculation unit 23 uses the following (Equation 3) to obtain a tightening torque T based on the striking energy E calculated by the energy calculation unit 22 and the output shaft rotation angle θ acquired by the rotation angle acquisition unit 20. Is calculated.
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, and specifically automatically stops the rotation of the motor 2. Hereinafter, a control example of automatic motor stop will be described.

Before starting the work, the user sets the target tightening torque value (hereinafter, also simply referred to as “target torque value”) according to the work target in the impact rotary tool 1. The reception unit 14 receives the operation input by the user and supplies it to the setting unit 15. The reception unit 14 has a wireless communication module, and the user may input an operation to the impact rotary tool 1 by using the remote controller attached to the tool. In the impact rotary tool 1 of the embodiment, the user can select one from the target torque values of 30 steps. The tool body may be provided with operation buttons and a touch panel, and the reception unit 14 may receive 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 shut-off hit number storage unit 17 and derives the shut-off hit number and the predetermined torque value corresponding to the target torque value. , Set in the control unit 10. The setting unit 15 supplies the shut-off striking number and a predetermined torque value to the control unit 10, and the control unit 10 sets the shut-off striking number so that the shut-off striking number can be used for the rotation control of the motor 2. Called processing.

The shut-off hit number storage unit 17 stores the number of hits from reaching a predetermined torque value to reaching the target torque value for each target torque value in 30 steps. The shut-off hit number storage unit 17 is configured as a master table, and the stored contents may not be updated.

During the work, the impact monitoring unit 25 monitors the output waveform of the impact detection unit 12, and when the output voltage of the impact detection unit 12 exceeds the impact determination voltage Vth, the impact mechanism 9 determines the occurrence of an impact. 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 number of impacts reaches the shutoff impact number, the motor 2 Stop the rotation. By such motor control, the impact rotary tool 1 controls the tightening torque with high accuracy.

In this way, the number of shut-off hits is used to manage the tightening torque. The manufacturer of the impact rotary tool 1 actually measures the number of shut-off impacts for realizing each of a plurality of tightening torque values using a predetermined screw member and socket, and creates a master table. In this way, the number of shut-off hits corresponding to each tightening torque value actually measured under a predetermined condition is recorded on the master table.

However, the threaded members and sockets to be actually worked on may differ from the threaded members and sockets used to create the master table. For example, if the socket used when creating the master table is a standard-scale impact socket, and the socket used in actual work is a long extension socket, the torsional rigidity of the socket itself will differ significantly. The rigidity also changes depending on the combination of the screw member and the socket. Ideally, the impact mechanism 9 collides with the hammer claw and the anvil claw in the trajectory shown in FIGS. 4 (a) to 4 (d), but in actual work, the torsional rigidity Due to various factors such as, the striking behavior may become inappropriate. 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 types (modes) of improper striking behavior will be described.
FIG. 6A shows a first mode of improper striking behavior. In this first mode, after the hammer claw 6a hits the anvil claw 7b, the hammer 6 retracts 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, causing noise and vibration, and further, the cam mechanism may be damaged. Factors that cause the first mode include insufficient forward force by the spring 4 and excessive rotation speed of the hammer 6.

FIG. 6B shows an example of the output waveform of the impact detection unit 12 in the first mode. In the output waveform shown in FIG. 6B, _{the striking pulse at time t n} is the detection of the striking of the anvil claw 7b by the hammer claw 6a in FIG. 6A. In the first mode, after the hammer 6 hits the anvil claw 7b by the hammer claw 6a, when the hammer 6 retracts to the maximum retracted position by the cam mechanism, the steel ball collides with the cam groove end portion, so that the hit detection unit 12 is timed. The vibration pulse 41 is output at _a time ta that is closer to the 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 the impact detection unit 12 _{outputs the impact pulse at time t n} and t _{n + 1} , the impact monitoring unit 25 identifies that the impact behavior by the 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 impact monitoring unit 25 may specify the type of improper impact behavior according to the output waveform of the impact detection unit 12. It relates to an output waveform shown in FIG. 6 (b), the striking monitoring unit 25 identifies that the time interval t _a time t _n and the vibration pulse 41 of the striking pulse, the striking behavior of the first mode has occurred You can.

FIG. 7A shows a second mode of improper striking behavior. In this second mode, when the hammer claw 6a hits the anvil claw 7a, then retreats once and then heads toward the anvil claw 7b, a shortage of the amount of advance occurs. As a result, the hammer claw 6a cannot hit the side surface of the anvil claw 7b, and operates so as to move toward the next anvil claw 7a while scraping the bottom surface of the anvil claw 7b. This may reduce the tightening torque and cause uneven wear of the hammer claws and anvil claws. Factors that cause the second mode include insufficient forward force by the spring 4 and excessive rotation speed of the hammer 6.

FIG. 7B shows an example of the output waveform of the impact detection unit 12 in the second mode. In the output waveform shown _{in FIG. 7B, the striking pulse at time t n} is the detection of the striking of the anvil claw 7a by the hammer claw 6a in FIG. 7A. In the second mode, after the hammer claw 6a hits the anvil claw 7a, the front surface of the hammer claw 6a comes into contact with the bottom surface of the anvil claw 7b, so that the hit detection unit 12 is located at an intermediate position between _{time t n} and t _{n + 1.} The vibration pulse 42 is output at a _{time t b} close to a time t _{n + 1.}

When the vibration pulse 42 is output from the impact detection unit 12 at time t _b , the impact monitoring unit 25 identifies that the impact behavior by the impact mechanism 9 is improper. Further, the impact monitoring unit 25 identifies that the impact behavior of 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 with respect to the output waveform shown in FIG. 7 (b). You can do it.

The first mode and the second mode occur due to insufficient forward force of the hammer 6 due to the spring 4 and excessive rotation speed of the hammer 6. One of the practical methods to eliminate this factor is to reduce the rotation speed of the hammer 6. By appropriately reducing the rotation speed of the hammer 6, the factors that cause the first mode and the second mode can be eliminated, and the striking behavior of the impact mechanism 9 can be corrected.

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

The user uses the remote controller to input an operation for lowering the upper limit rotation speed Nmax of the motor 2. When the reception unit 14 receives an operation input from the user, the setting unit 15 changes so as to lower the upper limit rotation speed Nmax of the motor 2. When the setting unit 15 lowers the upper limit rotation speed Nmax, the motor control unit 24 reduces the rotation speed of the motor 2 as compared with the time when the first mode or the second mode is generated. Then, the user performs the tightening work using the impact rotary tool 1 after changing the upper limit rotation speed Nmax, and confirms whether the striking behavior is appropriate. When the information indicating the type of improper striking behavior is redisplayed on the display unit 30 during or after the work, the user readjusts the upper limit rotation speed Nmax using the remote controller. By adjusting the upper limit rotation speed Nmax until the error display disappears on the display unit 30, the optimum upper limit rotation speed Nmax for the combination of the screw member and the socket is derived.

When the upper limit rotation speed Nmax is lowered, the striking energy due to one striking becomes small, so that the user needs to reset a large number of shut-off striking. In the impact rotary tool 1 of the embodiment, the shut-off impact number is increased by the user selecting a target torque value higher than the target torque value before lowering the upper limit rotation speed Nmax from the target torque values of 30 steps. be able to. Therefore, when the user lowers the upper limit rotation speed Nmax, the impact rotary tool 1 can perform appropriate torque control by simultaneously setting a high target torque value for determining the shutoff impact number.

FIG. 8A shows a third mode of improper striking behavior. In this third mode, after the hammer claw 6a hits the anvil claw 7b, the amount of retreat is insufficient, and the anvil claw 7b is hit again, or the striking surface of the anvil claw 7b is rubbed up. This may reduce the tightening torque and cause uneven wear of the hammer claws and anvil claws. The factors that cause the third mode are that the forward force of the spring 4 is too large and that the rotation speed of the hammer 6 is too small.

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

Vibration When the pulse 43 is outputted by the striking detection section 12 time t _c, the striking monitoring unit 25 identifies that the striking behavior of the impact mechanism 9 is improper. Further, the striking monitoring unit 25 identifies that the striking behavior of the third mode is generated by the interval between _{the striking pulse time t n + 1} and the vibration pulse 43 time t _c with respect to the output waveform shown in FIG. 8 (b). You can do it.

FIG. 9A shows a fourth mode of improper striking behavior. In this fourth mode, after the hammer claw 6a hits the anvil claw 7a, it contacts the anvil 7 before hitting the anvil claw 7b due to an excessive amount of advancement. As a result, the tightening torque may decrease, and the hammer claws and anvil claws may be unevenly worn, resulting in increased vibration and noise. The factors that cause the fourth mode are that the forward force of the spring 4 is too large and that the rotation speed of the hammer 6 is too small.

FIG. 9B shows an example of the output waveform of the impact detection unit 12 in the fourth mode. In the output waveform shown in FIG. 9B, _{the striking pulse at time t n} is the detection of the striking of the anvil claw 7a by the hammer claw 6a in FIG. 9A. In the fourth mode, after the hammer claw 6a hits the anvil claw 7a, the front surface of the hammer claw 6a comes into contact (collision) with the surface of the anvil 7, so that the hit detection unit 12 makes _{a time t d} immediately before the time t _{n + 1.} Outputs the vibration pulse 44 with.

When the vibration pulse 44 is output from the impact detection unit 12 at time t _d , the impact monitoring unit 25 identifies that the impact behavior by the impact mechanism 9 is improper. Further, the impact monitoring unit 25 identifies 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. 9 (b). You can do it.

The third mode and the fourth mode occur due to the fact that the forward force of the hammer 6 by the spring 4 is too large and the rotation speed of the hammer 6 is too small. One of the practical methods to eliminate this factor is to increase the rotation speed of the hammer 6. By appropriately increasing the rotation speed of the hammer 6, the factors that cause the third mode and the fourth mode can be eliminated, and the striking behavior of the impact mechanism 9 can be corrected.

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

The user uses the remote controller to input an operation for increasing the upper limit rotation speed Nmax of the motor 2. When the reception unit 14 receives an operation input from the user, the setting unit 15 changes so as to increase the upper limit rotation speed Nmax of the motor 2. When the setting unit 15 raises the upper limit rotation speed Nmax, the motor control unit 24 increases the rotation speed of the motor 2 as compared with the time when the third mode or the fourth mode is generated. Then, the user performs the tightening work using the impact rotary tool 1 after changing the upper limit rotation speed Nmax, and confirms whether the striking behavior is appropriate. When the information indicating the type of improper striking behavior is redisplayed on the display unit 30 during or after the work, the user readjusts the upper limit rotation speed Nmax using the remote controller. By adjusting the upper limit rotation speed Nmax until the error display disappears on the display unit 30, the optimum upper limit rotation speed Nmax for the combination of the screw member and the socket is derived.

When the upper limit rotation speed Nmax is increased, the striking energy due to one striking increases, so that the user needs to reset the shut-off striking number to a small value. When the user raises the upper limit rotation speed Nmax, the impact rotary tool 1 can perform appropriate torque control by simultaneously setting a low target torque value that determines the shutoff impact number.

The present invention has been described above based on the embodiments. This embodiment is an example, and it will be understood by those skilled in the art that various modifications are possible for each of these components or combinations of each processing process, and that such modifications are also within the scope of the present invention. ..

In the embodiment, the impact monitoring unit 25 determines whether the impact behavior is appropriate or inappropriate, and provides an opportunity for the user to manually adjust the upper limit rotation speed Nmax of the motor 2, but the user uses it before starting the work. The upper limit rotation speed Nmax can be freely changed according to the socket to be used and the usage environment.

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

The outline of the aspect of the present invention is as follows.
The impact rotary tool (1) according to an aspect of the present invention includes an impact mechanism (9) that generates an intermittent rotary striking force on the output shaft (8) by a motor output, and an output shaft (8) by the impact mechanism (9). A striking detection unit (12) for detecting the impact applied to the striking unit and a striking monitoring unit (25) for monitoring the output waveform of the striking detection unit (12) are provided. From the output waveform of (12), it is specified whether or not the striking behavior by the impact mechanism (9) is appropriate.

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

The impact rotary tool (1) has a rotation angle acquisition unit (20) that acquires the 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). ), And the tightening torque based on the striking energy calculated by the energy calculating unit (22) and the output shaft rotation angle acquired by the rotation angle acquisition unit (20). The tightening torque calculation unit (23) for calculating the above, and the motor control unit (24) for controlling the rotation of the motor (2) based on the calculated tightening torque may be provided. The motor control unit (24) may limit the upper limit rotation speed of the motor (2) to a predetermined value.

The impact rotary tool (1) of another aspect of the present invention has an impact mechanism (9) that generates an intermittent rotary striking force on the output shaft (8) by the motor output, and an output shaft (8) by the impact mechanism (9). The impact detection unit (12) that detects the impact applied to), the rotation angle acquisition unit (20) that acquires the output shaft rotation angle by one impact of the impact mechanism (9), and the impact mechanism (9). The energy calculation unit (22) that calculates the impact energy applied to the output shaft (8) by one impact, and the impact energy calculated by the energy calculation unit (22) and the output acquired by the rotation angle acquisition unit (20). A tightening torque calculation unit (23) that calculates the 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. A setting unit (15) for changing the upper limit rotation speed of the motor (2) is provided.

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 ... Impact detection unit, 13 ... Battery, 14 ... Reception unit, 15 ... Setting unit , 16 ... Operation switch, 17 ... Shut-off hit number storage unit, 18 ... Rotation angle detection unit, 20 ... Rotation angle acquisition unit, 21 ... Rotation speed acquisition unit, 22 ... Energy calculation unit, 23 ... Tightening torque calculation unit, 24 ... Motor control unit, 25 ... Impact monitoring unit, 30 ... Display unit.

Claims (5)

An impact mechanism that generates an intermittent rotational impact force on the output shaft by the motor output,
An impact detection unit that detects the impact applied to the output shaft by the impact mechanism,
An impact rotary tool including a impact monitoring unit that monitors the output waveform of the impact detection unit.
The impact monitoring unit identifies the type of improper impact behavior from the pulse and the pulse time interval in the output waveform of the impact detection unit.
Impact rotary tool that is characterized by that. The impact detection unit includes an impact sensor that detects an impact and an amplifier that amplifies the output of the impact sensor.
The impact monitoring unit detects a pulse in which the output voltage of the impact detection unit exceeds the impact determination voltage.
The impact rotary tool according to claim 1. A display unit for displaying the result specified by the impact monitoring unit is further provided.
The impact rotary tool according to claim 1 or 2. A setting unit for changing the upper limit rotation speed of the motor by user operation is further provided.
The impact rotary tool according to any one of claims 1 to 3. A rotation angle acquisition unit that acquires the output shaft rotation angle by one impact of the impact mechanism, and a rotation angle acquisition unit.
An energy calculation unit that calculates the impact energy applied to the output shaft by a single impact of the impact mechanism,
A tightening torque calculation unit that calculates the tightening torque based on the striking energy calculated by the energy calculation unit and the output shaft rotation angle acquired by the rotation angle acquisition unit.
It is equipped with 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 rotation speed of the motor to a predetermined value.
The impact rotary tool according to any one of claims 1 to 4.

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