JP6782428B2 - Impact rotary tool - Google Patents

Description

The present invention relates to an impact rotary tool that tightens screw members such as bolts and nuts by intermittent rotary impact force.

In the mechanical impact rotary tool, a hammer rotating at the motor output hits the anvil in the rotational direction to generate an intermittent rotational impact force on the output shaft to tighten the screw member. Further, in the oil pulse tool, which is a kind of impact rotary tool, the liner rotating at the motor output creates a pressure difference between the oil chambers to generate an intermittent rotary impact force on the output shaft 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.

In order to improve the control accuracy of the tightening torque, it is preferable to provide a torque measuring means on the output shaft to directly measure the actual tightening torque, but there is a problem that the cost and size of the tool are increased. Therefore, conventionally, an impact rotary tool having a shut-off function for automatically stopping the motor by estimating that the tightening torque has reached a set value has been provided. Patent Document 1 calculates the tightening torque by dividing the striking energy by the striking energy applied to the output shaft, the rotation angle of the output shaft between striking, and the rotation angle between striking. Disclosed is an impact rotary tool including means and means for stopping the rotary drive unit when the calculated tightening torque exceeds a specified value. In the impact rotary tool disclosed in Patent Document 1, the tightening torque T (= E / θ) is calculated by using the striking energy E and the output shaft rotation angle θ between striking, and the calculated tightening torque T is torque-controlled. I am using it for.

JP-A-2000-354976

In the impact rotary tool, as the tightening torque increases due to repeated striking, the output shaft rotation angle θ between striking decreases. Therefore, according to the method for calculating the tightening torque T according to Patent Document 1, the calculated value of the tightening torque T (= E / θ) is affected by the detection error of the rotation angle θ in the high torque region where the rotation angle θ becomes very small. There is a problem that the tightening torque T cannot be estimated accurately. Therefore, a technique for estimating the tightening torque T with high accuracy and improving the control accuracy of the tightening torque is desired.

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 estimating tightening torque with high accuracy and improving control accuracy of tightening torque.

In order to solve the above problems, the impact rotary tool of a certain aspect of the present invention detects an impact mechanism that generates an intermittent rotational impact force on the output shaft by the motor output and an impact applied to the output shaft by the impact mechanism. Impact detection unit, rotation angle acquisition unit that acquires the output shaft rotation angle by one impact of the impact mechanism, and energy calculation unit that calculates the impact energy applied to the output shaft by one impact of the impact mechanism. , The tightening torque calculation unit that calculates the 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, and the motor rotation stop based on the calculated tightening torque. It is an impact rotary tool equipped with a motor control unit for making the engine, and the tightening torque calculation unit integrates the integrated energy obtained by integrating the impact energy calculated for each impact and the output shaft rotation angle acquired for each impact. The tightening torque is calculated using the value divided by the integrated rotation angle.

According to the present invention, it is possible to provide a technique for estimating the tightening torque with high accuracy and improving the control accuracy of the tightening torque.

It is a figure which shows the structure of the impact rotary tool which concerns on embodiment. (A) to (c) are diagrams showing how a hammer hits an anvil in the rotational direction. It is a figure which shows the relationship between the actual torque for each impact number in an embodiment, and the calculated tightening torque. It is a figure which shows the relationship between the actual torque for each impact number and the estimated torque calculated by the comparison method. It is a figure which shows the correspondence relationship between the target torque value stored in the shut-off impact number storage part, and the shut-off impact number.

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 a rechargeable battery built in the battery pack. The motor 2 which is a drive source is driven by the motor drive unit 11, and 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.

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 impact 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 includes a rotation angle acquisition unit 20, a rotation speed acquisition unit 21, an energy calculation unit 22, a tightening torque calculation unit 23, and a motor control unit 24, and the tightening torque is calculated and calculated. It has a function of controlling the rotation of the motor 2 based on the above.

The operation switch 16 is a trigger switch operated by the user, and the motor control unit 24 controls the on / off of the motor 2 by operating the operation switch 16 and drives the motor according to the operation amount of the operation switch 16. It is supplied to the unit 11. The motor drive unit 11 controls the applied voltage of the motor 2 according to a drive instruction supplied from the motor control unit 24 to adjust the motor rotation speed.

The impact detection unit 12 detects the impact applied to the anvil 7 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 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 striking sound.

The rotation angle detection unit 18 detects the rotation angle of the motor 2 and / or the output shaft 8. 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 impact of 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".

2 (a) to 2 (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. 2A shows a state in which the hammer claw and the anvil claw are engaged in the circumferential direction. The hammer claw 6a and the hammer claw 6b engage with the anvil claw 7a and the anvil claw 7b, respectively, and apply a rotational force in the direction indicated by the arrow A.
FIG. 2B shows a state in which the engagement state between the hammer claw and the anvil claw is released. When a load exceeding a predetermined value acts between the hammer 6 and the anvil 7 in the engaged state, the hammer 6 retracts by a cam mechanism (not shown), and the hammer claw 6a and the anvil claw 7a are engaged and the hammer The engagement state between the claw 6b and the anvil claw 7b is released.
FIG. 2C shows a state in which the hammer claw hits the anvil claw and rotates 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 the hammer claws 6b move forward, respectively. 7b, hit the anvil claw 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).

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 due to 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 reduction gear 3.
Since the tightening torque of the screw member increases each time the hammer 6 strikes the anvil 7, the output shaft rotation angle θ acquired for each impact after the screw member is seated tends to gradually decrease.

In the embodiment, the rotation angle acquisition unit 20 acquires the output shaft rotation angle θ from the motor rotation angle detection signal, but in another example, the rotation angle detection unit 18 directly detects the rotation angle θ of the anvil 7. May be good. At this time, the rotation angle acquisition unit 20 can acquire the output shaft rotation angle θ between impacts based on the anvil rotation angle detection signal supplied from the rotation angle detection unit 18.

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 impacts from the timer output and calculates the striking 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 impact energy E is calculated.
E = (1/2) x J x ω ² ... (Equation 2)

In the embodiment, the tightening torque calculation unit 23 calculates the 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.

The tightening torque calculation unit 23 of the embodiment integrates the integrated energy (ΣE) obtained by integrating the impact energy E calculated for each impact, and the integrated rotation angle (Σθ) obtained by integrating the output shaft rotation angle θ acquired for each impact. The tightening torque T is calculated using the value divided by. In the embodiment, the value obtained by dividing the integrated energy (ΣE) by the integrated rotation angle (Σθ) is calculated as the tightening torque T.
T = ΣE / Σθ ・ ・ ・ (Equation 3)
Since the rotation angle θ and the striking speed ω may not be stably obtained between the first and several impacts, the tightening torque calculation unit 23 may perform the nth time (n is an integer of 2 or more) or later. The tightening torque T may be calculated by integrating the rotation angle θ from the impact and the impact energy E.

FIG. 3 shows the relationship between the actual torque for each number of impacts and the tightening torque (estimated torque) calculated by the tightening torque calculation unit 23. FIG. 3 shows that the tightening torque calculation unit 23 can estimate the tightening torque with high accuracy by calculating the tightening torque T by (Equation 3).

Hereinafter, as a comparative example, the calculation method of the estimated torque in Patent Document 1 is shown. In Patent Document 1, the estimated torque Tcom is calculated by the following (Equation 4).
Tcom = E / θ (Equation 4)
As a comparative example, FIG. 4 shows the relationship between the actual torque for each impact number and the estimated torque calculated by the comparison method. According to (Equation 4), the calculated value of the estimated torque Tcom is greatly affected by the detection error of the rotation angle θ in the high torque region where the rotation angle θ becomes small. Therefore, as shown in FIG. 4, according to the calculation method of the comparative example, the estimated torque Tcom fluctuates greatly.

On the other hand, the tightening torque calculation unit 23 of the embodiment calculates the tightening torque T using the integrated energy (ΣE) and the integrated rotation angle (Σθ), so that the detection error for each impact is the estimation accuracy of the tightening torque. The impact on is reduced. The motor control unit 24 improves the control accuracy of the tightening torque by stopping the rotation of the motor 2 based on the high-precision tightening torque T calculated by the tightening torque calculation unit 23. An embodiment of automatic stop control of the motor 2 will be described below.

(Example 1)
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. During the tightening operation, the impact rotary tool 1 counts the number of impacts detected by the impact detection unit 12, and when the counted number of impacts reaches the number of impacts corresponding to the target torque value (shut-off impact number), the motor 2 Executes the shut-off function that automatically stops the rotation.

The shut-off impact number storage unit 17 of the first embodiment stores the number of impacts (shut-off impact number) from the start of the impact by the impact mechanism 9 until the tightening torque reaches the target torque value. The shut-off impact number storage unit 17 stores, for example, the shut-off impact number corresponding to each of the set values in 30 steps. This means that the user can select one of the tightening torque values of 30 steps according to the work target. The shut-off impact number storage unit 17 is configured as a master table, and the stored contents may not be updated. The setting unit 15 sets the shut-off impact number of the impact mechanism 9 in the control unit 10 with reference to the stored contents of the shut-off impact number storage unit 17.

FIG. 5 shows the correspondence between the target torque value stored in the shut-off impact number storage unit 17 and the shut-off impact number. For example, when the target torque value is set to 50 [Nm], the setting unit 15 sets the shut-off impact number to "55 times" with reference to the stored contents of the shut-off impact number storage unit 17.

The shut-off impact number storage unit 17 may store information or data for the setting unit 15 to derive the shut-off impact number corresponding to the target torque value. For example, the shut-off impact number is stored from the target torque value. A calculation formula for calculating and obtaining may be stored. Conventionally, it has been known that the tightening torque by the impact rotary tool is proportional to the square root of the number of hits. Therefore, the manufacturer of the impact rotary tool 1 measures the number of shut-off impacts for realizing a plurality of tightening torque values using a predetermined screw member and a member to be fastened, and measures a torque coefficient which is a proportional constant in the calculation formula. k may be obtained and stored in the shut-off impact number storage unit 17.

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 uses a remote controller attached to the tool to input an operation to the impact rotary tool 1. The tool body may be provided with operation buttons and a touch panel, and the reception unit 14 may accept operation input by the user.

Before starting work, the user selects the target torque value using the remote controller. When the receiving unit 14 receives the selection input of the target torque value, the setting unit 15 refers to the stored contents of the shutoff impact number storage unit 17 and derives the shutoff impact number corresponding to the target torque value, and the control unit 10 Supply to. In the first embodiment, the setting unit 15 derives the shut-off impact number and supplies it to the control unit 10, and the control unit 10 makes the shut-off impact number available for rotation control of the motor 2. This is called the number setting process.

During the work, the control unit 10 monitors the output voltage 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 impacts the output shaft 8 to provide an intermittent rotational impact force. Is determined to have occurred. The control unit 10 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 an intermittent rotational impact force is generated on the output shaft 8. ..

The motor control unit 24 counts the number of impacts detected by the impact detection unit 12. The motor control unit 24 automatically stops the rotation of the motor 2 when the counted number of impacts reaches the shutoff impact number. At this time, the tightening torque value of the screw member needs to be a target torque value set by the user.

Depending on the screw member to be worked on and the member to be fastened, a load equal to or higher than a predetermined value (hereinafter, also referred to as "intermediate load") is applied between the hammer 6 and the anvil 7 before the screw member is seated on the member to be fastened. As a result, the hammer 6 may hit the anvil 7. In this case, when the motor control unit 24 stops the rotation of the motor 2 with the shut-off impact number, the number of impacts (impacts) is consumed by the intermediate load, so that the tightening torque value of the bolt after fastening is the user. Does not reach the target torque value set by. Therefore, the motor control unit 24 of the first embodiment has a function of correcting the shut-off impact number set by the setting unit 15 when an intermediate load is generated.

Returning to FIG. 1, the reference impact number storage unit 19 stores the number of impacts from the start of the impact by the impact mechanism 9 until the tightening torque reaches a predetermined torque value smaller than the target torque value. The reference impact number storage unit 19 may be replaced by the shut-off impact number storage unit 17. FIG. 5 shows the storage contents of the shut-off impact number storage unit 17, but the shut-off impact number storage unit 17 reaches a torque value smaller than the target torque value (50 [Nm]) set by the user. I remember the number of impacts. In this sense, the reference impact number storage unit 19 may be substituted by the shutoff impact number storage unit 17. In the example shown in FIG. 5, the number of impacts until reaching 30 [Nm] is stored as "14 times".

The motor control unit 24 counts the impacts detected by the impact detection unit 12, and the number of impacts when the tightening torque calculated by the tightening torque calculation unit 23 reaches a predetermined torque value (30 [Nm]). From the relationship between M and the number of impacts (14 times) stored in the reference impact number storage unit 19, the shutoff impact number (55 times) set by the setting unit 15 is corrected. Specifically, the motor control unit 24 stores the impact number M when the tightening torque calculated by the tightening torque calculation unit 23 reaches a predetermined torque value (30 [Nm]) and the reference impact number storage unit 19. The difference from the number of impacts (14 times) is added to the number of shut-off impacts (55 times) set by the setting unit 15, and when the counted number of impacts becomes the number of shut-off impacts to which the difference is added, the motor Stop the rotation of 2.

For example, when the number of impacts M when the tightening torque calculated by the tightening torque calculation unit 23 reaches a predetermined torque value (30 [Nm]) is "20 times", the motor control unit 24 performs an intermediate load. It is recognized that the torque value reached by 14 impacts without it requires 6 extra impacts. Therefore, the motor control unit 24 adds "6 times" to the shut-off impact number (55 times) set by the setting unit 15 to correct the shut-off impact number to "61 times". As described above, in the first embodiment, the motor control unit 24 improves the torque control accuracy by stopping the rotation of the motor 2 based on the tightening torque estimated with high accuracy.

(Example 2)
In the first embodiment, the shut-off impact number storage unit 17 stores the number of impacts (shut-off impact number) from the start of the impact by the impact mechanism 9 until the tightening torque reaches the target torque value. On the other hand, in the second embodiment, the shut-off impact number storage unit 17 stores the number of impacts (shut-off impact number) from when the tightening torque reaches a predetermined torque value to when it reaches the target torque value. ..

For example, in FIG. 5, the number of impacts from reaching a predetermined torque value of 30 [Nm] to reaching a target torque value of 50 [Nm] is 41 times (= 55 times-14 times). The shut-off impact number storage unit 17 of the second embodiment stores the number of impacts from reaching a predetermined torque value to reaching the target torque value for each target torque value. Here, the predetermined torque value is preferably set as the torque value at the time of or after the screw member is seated so that the intermediate load does not affect the number of shut-off impacts in the second embodiment.

In the second embodiment, the setting unit 15 sets the shut-off impact number in the control unit 10 from when the tightening torque reaches a predetermined torque value to when it reaches the target torque value. When the tightening torque calculated by the tightening torque calculation unit 23 reaches a predetermined torque value, the motor control unit 24 counts the impact detected by the impact detection unit 12, and the counted impact number is the shut-off impact number. When it becomes, the rotation of the motor 2 is stopped. Accurate tightening torque control can be realized by the motor control unit 24 performing automatic stop control of the motor 2 based on the tightening torque estimated with high accuracy by the tightening torque calculation unit 23.

The present invention has been described above based on the embodiments and examples. It will be appreciated by those skilled in the art that these embodiments and examples are exemplary and that various modifications are possible for each of these components or combinations of processing processes, and that such modifications are also within the scope of the present invention. It is about to be.

In the first and second embodiments, torque control using the number of shut-off impacts is performed, but in the modified example, the motor control unit utilizes the fact that the tightening torque calculation unit 23 can accurately calculate the tightening torque. The 24 may stop the rotation of the motor 2 when the tightening torque calculated by the tightening torque calculation unit 23 reaches the target torque value. That is, when the tightening torque calculated by the tightening torque calculation unit 23 reaches the target torque value, the motor control unit 24 may stop the rotation of the motor 2.

The impact rotary tool 1 of the embodiment is equipped with a motor 2 which is an electric motor as a drive source, but another type of motor, for example, an air motor may be mounted. Further, although the impact rotary tool 1 of the embodiment is a mechanical rotary tool, it may be another type of impact rotary tool, for example, an oil pulse tool.

The outline of the aspect of the present invention is as follows.
The impact rotary tool (1) of an aspect of the present invention has an impact mechanism (9) that generates an intermittent rotational impact force on the output shaft (8) by the motor output, and an impact applied to the output shaft by the impact mechanism. The impact detection unit (12) to detect, the rotation angle acquisition unit (20) to acquire the output shaft rotation angle by one impact of the impact mechanism, and the impact energy applied to the output shaft by one impact of the impact mechanism. The energy calculation unit (22) that calculates the tightening torque, and the tightening torque calculation unit (23) that calculates the 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 (24) that stops the rotation of the motor based on the calculated tightening torque is provided. The tightening torque calculation unit (23) uses a value obtained by dividing the integrated energy obtained by integrating the impact energy calculated for each impact by the integrated rotation angle obtained by integrating the output shaft rotation angles acquired for each impact. Calculate the attached torque.

The impact rotary tool (1) may further include a setting unit (15) for setting the number of shut-off impacts from when the tightening torque reaches a predetermined torque value to when it reaches a target torque value. When the tightening torque calculated by the tightening torque calculation unit (23) reaches a predetermined torque value, the motor control unit (24) counts the impact detected by the impact detection unit (12) and counts the impact. When the number reaches the shut-off impact number, the rotation of the motor (2) may be stopped.

The motor control unit (24) may stop the rotation of the motor when the tightening torque calculated by the tightening torque calculation unit (23) reaches the target torque value.

The impact rotary tool (1) has a setting unit (15) that sets the number of shut-off impacts from the start of the impact by the impact mechanism to the time when the tightening torque reaches the target torque value, and the impact by the impact mechanism is started. A reference impact number storage unit (19) for storing the number of impacts until the tightening torque reaches a predetermined torque value smaller than the target torque value is further provided, and the motor control unit (24) is an impact detection unit ( The impact detected in 12) is counted, and the number of impacts when the tightening torque calculated by the tightening torque calculation unit (23) reaches a predetermined torque value and the number of impacts are stored in the reference impact number storage unit (19). It is preferable to correct the shut-off impact number set by the setting unit (15) in relation to the impact number. The motor control unit (24) sets the difference between the number of impacts when the tightening torque calculated by the tightening torque calculation unit reaches a predetermined torque value and the number of impacts stored in the reference impact number storage unit. The rotation of the motor may be stopped when the number of impacts counted by adding to the number of shut-off impacts set by the unit reaches the number of shut-off impacts to which the difference is added.

1 ... Impact rotary tool, 2 ... Motor, 8 ... Output shaft, 9 ... Impact mechanism, 10 ... Control unit, 11 ... Motor drive unit, 12 ... Impact detection unit , 14 ... reception unit, 15 ... setting unit, 16 ... operation switch, 17 ... shut-off impact number storage unit, 18 ... rotation angle detection unit, 19 ... reference impact number storage Units, 20 ... Rotation angle acquisition unit, 21 ... Rotation speed acquisition unit, 22 ... Energy calculation unit, 23 ... Tightening torque calculation unit, 24 ... Motor control 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, and an output shaft rotation due to a single impact of the impact mechanism. A rotation angle acquisition unit that acquires an angle, an energy calculation unit that calculates the impact energy applied to the output shaft by a single impact of the impact mechanism, and an impact energy calculated by the energy calculation unit and the rotation angle acquisition unit. It is an impact rotary tool equipped with a tightening torque calculation unit that calculates the tightening torque based on the output shaft rotation angle acquired by the company, and a motor control unit that stops the rotation of the motor based on the calculated tightening torque. hand,
The tightening torque calculation unit uses a value obtained by dividing the integrated energy obtained by integrating the impact energy calculated for each impact by the integrated rotation angle obtained by integrating the output shaft rotation angles acquired for each impact, and using the tightening torque. To calculate,
Impact rotary tool characterized by that. It also has a setting unit that sets the number of shut-off impacts from when the tightening torque reaches a predetermined torque value to when it reaches the target torque value.
When the tightening torque calculated by the tightening torque calculation unit reaches a predetermined torque value, the motor control unit counts the impact detected by the impact detection unit, and the counted impact number is the shut-off impact number. When it becomes, the rotation of the motor is stopped,
The impact rotary tool according to claim 1. The motor control unit stops the rotation of the motor when the tightening torque calculated by the tightening torque calculation unit reaches the target torque value.
The impact rotary tool according to claim 1. A setting unit that sets the number of shut-off impacts from the start of the impact by the impact mechanism until the tightening torque reaches the target torque value, and the tightening torque from the target torque value after the impact by the impact mechanism is started. It is further equipped with a reference impact number storage unit that stores the number of impacts until a small predetermined torque value is reached.
The motor control unit counts the impacts detected by the impact detection unit, and the number of impacts when the tightening torque calculated by the tightening torque calculation unit reaches a predetermined torque value and the reference impact number. The shut-off impact number set by the setting unit is corrected from the relationship with the impact number stored in the storage unit.
The impact rotary tool according to claim 1. The motor control unit determines the difference between the number of impacts when the tightening torque calculated by the tightening torque calculation unit reaches a predetermined torque value and the number of impacts stored in the reference impact number storage unit. When the number of impacts counted by adding to the number of shutoff impacts set by the setting unit reaches the number of shutoff impacts to which the difference is added, the rotation of the motor is stopped.
The impact rotary tool according to claim 4.

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