JP6135925B2 - Impact rotary tool and tip attachment for impact rotary tool - Google Patents

Description

  The present invention relates to an impact rotary tool and a tip attachment for an impact rotary tool.

  An impact rotary tool is a tool that converts the rotation output of a motor, which is an example of a drive source, to a pulsed impact torque by hammering or hydraulic pressure, and performs tightening or relaxation work using the impact torque. is there. According to the impact rotary tool, workability is improved because a higher torque can be obtained as compared with the rotary tool using only the speed reduction mechanism. Therefore, impact rotary tools are widely used in construction sites and assembly factories (see, for example, Patent Document 1).

  In impact rotary tools, the object may be over-tightened by high torque, but in order to avoid such over-tightening, the object is tightened loosely so that the object such as a bolt or screw has the desired strength. It may not be fixed.

  Therefore, in the impact rotary tool, in order to tighten the object with a predetermined torque, the torque is measured by a sensor such as a torque sensor provided on the shaft portion. When the torque based on the output value of the sensor reaches a predetermined torque such as a target torque, the driving of the motor is stopped.

JP 2012-206181 A

  By the way, in the impact rotary tool as described above, the torque applied to the shaft portion is measured, but it is difficult to calculate the actual tightening torque from the measured torque, and depending on the target work, there is a possibility of stopping at a completely different tightening torque. is there.

  The present invention has been made to solve the above-described problems, and an object thereof is to provide an impact rotary tool and a tip attachment for an impact rotary tool capable of calculating a tightening torque with higher accuracy. .

In order to solve the above problems, an impact force generator that generates an impact force by changing the power of the drive source to a pulsed torque, and a shaft that transmits the pulsed torque to the tip tool by the generated impact force A torque measuring unit that measures a measurement torque that is a torque applied to the shaft, a rotation angle measuring unit that measures a rotation angle of the shaft, a maximum angle at the last hit, and a maximum at the current hit Calculating an approximate curve of the rotation angle in a predetermined period including at least a part of the tightening period corresponding to the difference from the angle, calculating an angular acceleration based on the calculated approximate curve of the rotation angle, and calculating the angular acceleration and A calculation unit that calculates a tightening torque based on the measured torque, and a control unit that controls the drive source based on the tightening torque.
In the above configuration, it is preferable that the calculation unit calculates the tightening torque based on the measured torque measured in the predetermined period.

Further, in the above configuration, the calculation unit has T = Ts × A−I, where T is the tightening torque, Ts is the measurement torque, I is the moment of inertia around the rotation axis of the tip tool, and α is the angular acceleration. It is preferable to calculate the tightening torque using × α × B + C (where A, B, and C are coefficients).

In the above configuration, the calculation unit preferably calculates the angular acceleration by performing the second derivative of the previous SL trendline before Symbol rotation angle.

  In the above configuration, the calculation unit may calculate the angular acceleration by calculating the approximate curve of the rotation angle as a second-order approximate curve and performing the second derivative of the calculated second-order approximate curve. preferable.

In the above configuration, the calculation unit as the measured torque and the angular acceleration, it is preferable to use the average of the values in each within the predetermined time period.

In the above configuration, the measured torque measured by the torque measuring unit is preferably a peak value within the predetermined period .
In order to solve the above problems, a torque measuring unit that measures a measurement torque that is a torque applied to a shaft part that transmits an impact force generated by an impact rotary tool to a tip tool, and a rotation angle that measures a rotation angle of the shaft part Calculate the approximate curve of the rotation angle in a predetermined period including at least a part of the tightening period corresponding to the difference between the measurement unit, the maximum angle at the time of the last hit, and the maximum angle at the time of the current hit, An angular acceleration is calculated based on the approximate curve of the rotation angle, and a calculation unit is provided that calculates a tightening torque based on the angular acceleration and the measured torque.

  According to the impact rotary tool and the tip attachment for the impact rotary tool of the present invention, the tightening torque can be calculated with higher accuracy.

It is a model side sectional view of an impact rotary tool in an embodiment. It is a block diagram which shows the electrical structure of an impact rotary tool. It is a flowchart which shows an example of operation | movement of an impact rotary tool. (A) It is a graph which shows an axial torque sensor output, (b) is a graph which shows the pulse signal of a rotary encoder, (c) is a graph which shows the angle change accompanying shaft part rotation. It is a graph which shows the waveform of the voltage signal output from a torque calculation part. A method for calculating the angular acceleration of an impact rotary tool in another example will be described. It is a typical sectional side view for demonstrating the impact rotary tool and the tip attachment for impact rotary tools in another example.

Hereinafter, an embodiment of an impact rotary tool will be described with reference to the drawings.
As shown in FIG. 1, the impact rotary tool 11 is a hand-held type that can be gripped, and is, for example, an impact driver or an impact wrench. The main body housing 12 that forms the exterior of the impact rotary tool 11 includes a bottomed cylindrical body portion 13 and a handle portion 14 that extends from the body portion. The handle portion 14 extends in one direction intersecting the axis of the trunk portion 13 and extends downward from the trunk portion 13 in FIG.

  A motor 15 as an example of a drive source is disposed on the base end side in the body 13 and on the right side in FIG. The motor 15 is disposed in the body portion 13 so that the rotation axis of the motor 15 coincides with the axis line of the body portion 13 and the output shaft 16 of the motor 15 faces the front end side of the body portion 13. The motor 15 is a DC motor such as a brush motor or a brushless motor. An impact force generator 17 is connected to the output shaft 16 of the motor 15. The impact force generator 17 generates impact force by converting the rotational power of the motor 15 into pulsed torque.

The impact force generation unit 17 includes a speed reduction mechanism 18, a hammer 19, an anvil 20, and a main shaft 21 that is an example of a shaft portion in order from the motor 15 side.
The reduction mechanism 18 decelerates the rotation of the motor 15 at a predetermined reduction ratio to obtain a necessary torque. The hammer 19 receives a rotational force that has been decelerated by the speed reduction mechanism 18 and increased in torque. The anvil 20 is hit by the hammer 19. A rotational force is impulsively applied to the main shaft 21 by striking the hammer 19. The main shaft 21 may be integrally formed with the anvil 20 as a part of the anvil 20, or the main shaft 21 formed separately from the anvil 20 may be fixed to the anvil 20.

  The hammer 19 is attached to a drive shaft 22 that is rotated by the output of the speed reduction mechanism 18. The hammer 19 is rotatable with respect to the drive shaft 22 and is slidable in the front-rear direction along the drive shaft 22. Further, the hammer 19 is urged toward the distal end side in the body portion 13 on the left side in FIG. 1 by the elastic force of the coil spring 23 interposed between the speed reduction mechanism 18 and the hammer 19, and the anvil 20. It arrange | positions in the position contact | abutted with.

  A pair of contact portions 19 a extending toward the anvil 20 are equally arranged on the hammer 19 along the circumferential direction, and each contact portion 19 a and the contact portion 20 a extending in the radial direction of the anvil 20 and the circumferential direction. Abut. The rotation of the drive shaft 22 decelerated by the speed reduction mechanism 18 is transmitted to the main shaft 21 coaxial with the anvil 20 when the hammer 19 and the anvil 20 rotate together via the contact portions 19a and 20a. The A chuck portion 13a for attaching / detaching the tip tool 24 while being inserted into the socket hole is provided at the left end portion in FIG.

  When tightening of a fastening member such as a bolt or a screw is advanced by the rotation of the tip tool 24, for example, the load applied to the main shaft 21 is larger than when tightening of the fastening member is started. Or, when the loosening of the fastening member such as a bolt or a screw is advanced by the rotation of the tip tool 24, for example, the load applied to the main shaft 21 is small compared to the start of the loosening of the fastening member. In a state where a predetermined force or more is applied between the hammer 19 and the anvil 20, the hammer 19 is rearward along the drive shaft 22 while compressing the coil spring 23, and moves to the right in FIG. . When the hammer 19 is rotated by a certain amount or more with respect to the anvil 20 by such movement, the compression force of the coil spring 23 is released, so that the hammer 19 strikes the anvil 20 by the urging force of the coil spring 23 while rotating. . The hammer 19 is struck repeatedly each time the hammer 19 rotates more than a certain amount with respect to the anvil 20 due to the load received by the main shaft 21. The hit of the anvil 20 by the hammer 19 acts on the fastening member as an impact.

As shown in FIG. 1, a shaft torque sensor 26 and a rotary encoder 27 are attached to the main shaft 21 of the impact rotary tool 11.
The shaft torque sensor 26 is, for example, a magnetostrictive strain sensor capable of detecting torsional strain, and is a coil installed in a non-rotating portion to change the magnetic permeability according to the strain of the shaft generated when torque is applied to the main shaft 21. And output a voltage signal proportional to the distortion. The voltage signal output from the shaft torque sensor 26 is a torque detection signal S1 corresponding to the torque (see FIG. 4A), and the torque detection signal S1 is transmitted from the shaft torque sensor 26 to the shaft torque measuring unit 41 of the main body control circuit 30. Is output.

The rotary encoder 27 outputs a two-phase pulse to the rotation angle calculation unit 42 by the rotation of the main shaft 21, and the rotation angle calculation unit 42 converts it into an angle change.
The handle portion 14 is provided with a trigger lever 29, and the impact rotary tool 11 is driven when the trigger lever 29 is operated by an operator. In addition, a battery pack mounting portion 31 formed of a substantially square box-shaped storage case is detachably provided at the lower end of the handle portion 14, and a battery pack 32 that is a secondary battery is provided in the battery pack mounting portion 31. Contained. The impact rotary tool 11 is a rechargeable type using the battery pack 32 as a driving power source. The battery pack 32 is connected to the main body control circuit 30 through the power line 33.

  The motor 15 is provided with a speed detector 34 that detects the rotational speed of the motor 15. The speed detection unit 34 is embodied as a frequency generator that generates a frequency signal having a frequency proportional to the rotation speed of the motor 15, for example. The speed detection unit 34 may be, for example, a rotary encoder, and when the motor 15 is a brushless motor, the speed detection unit 34 may be a Hall sensor, and detects the rotation speed by a signal from the Hall sensor or a counter electromotive force. be able to. The speed detection unit 34 outputs a signal corresponding to the rotation speed to the main body control circuit 30.

  The main body control circuit 30 is electrically connected to the motor 15 via the lead wire 35 and controls driving of the motor 15 and the like. In addition, a trigger switch that detects the operation of the trigger lever 29 is electrically connected to the main body control circuit 30.

  The main body control circuit 30 performs control such as changing the rotation speed of the motor 15 in accordance with the pulling amount of the trigger lever 29 when the operator operates the trigger lever 29. The main body control circuit 30 controls energization to the motor 15 via a motor driver, and performs rotation control and torque setting of the motor 15. Further, the main body control circuit 30 outputs a stop signal or the like when the calculated torque value calculated using the output of the shaft torque sensor 26 and the output of the rotary encoder 27 exceeds the torque set value.

  The main body control circuit 30 is electrically connected to the motor 15 via the lead wire 35 and controls driving of the motor 15 and the like. The main body control circuit 30 is connected to signal lines 36 and 37 for inputting signals from the shaft torque sensor 26 and the rotary encoder 27 to the main body control circuit 30.

Next, the electrical configuration of the impact rotary tool will be described with reference to FIG.
As shown in FIG. 2, the impact rotary tool 11 includes a shaft torque sensor 26, a rotary encoder 27, and a main body control circuit 30.

  The main body control circuit 30 receives the signal output from the shaft torque sensor 26 and receives the signal output from the rotary encoder 27 and the shaft torque measuring unit 41 that calculates the torque (measured torque) applied to the anvil 20 or the main shaft 21. And a rotation angle calculation unit 42 for calculating the rotation angle. Further, the main body control circuit 30 includes an angular acceleration calculation unit 43 that calculates angular acceleration based on the rotation angle calculated by the rotation angle calculation unit 42, and an inertia moment setting unit that inputs an inertia moment about the rotation axis of the tip tool 24. 44, and a torque calculation unit 45 that calculates the tightening torque based on the measured torque, the angular acceleration, and the moment of inertia. Note that the moment of inertia itself may be used as the moment of inertia, or a value corresponding to or proportional to the moment of inertia may be employed. Further, the main body control circuit 30 of the present embodiment is configured such that a waveform corresponding to one hit out of the measured torque calculated by the shaft torque measuring unit 41 is accumulated in the buffer unit 46.

  The main body control circuit 30 includes a control unit 50 that performs torque management, speed control, and the like of the motor 15. The control unit 50 includes a torque setting unit 51 that sets a set torque that is a target value of the tightening torque.

  The torque setting unit 51 includes, for example, a volume and is electrically connected to the speed limit calculation unit 53 and the stop determination unit 55. The set torque for stopping the driving of the motor 15 is set by the operation of the torque setting unit 51 by the operator. For example, the torque setting unit 51 sets the target torque To (see FIG. 5) within a range of ± 10% of the set torque. The torque setting unit 51 may be configured such that the set torque itself is the target torque To. In the present embodiment, the target torque To corresponds to an example of a predetermined torque value.

  The control unit 50 includes a motor speed measurement unit 52 that measures the rotation speed of the motor 15, the speed limit calculation unit 53 that calculates the speed limit, and a motor control unit 54 that controls the driving of the motor 15. The main body control circuit 30 is provided with a CPU, and the control unit 50 is composed of software in which the units 52 to 54 are constructed by the CPU executing a control program, for example. In addition, each part 52-54 which comprises the control part 50 is comprised with hardware by integrated circuits, such as ASIC, a part in each part 52-54 is comprised with software, and another part is hardware. It may be configured.

  The motor speed measurement unit 52 measures the rotation speed of the motor 15 based on a signal corresponding to the speed input from the speed detection unit 34. The speed limit calculation unit 53 inputs the measured rotational speed of the motor 15 and a preset target torque To, and the motor 15 when the trigger lever 29 is pulled according to the magnitude of the target torque To. The speed limit speed is calculated. The motor control unit 54 controls the drive of the motor 15 so as to limit the rotation speed of the motor 15 to be equal to or lower than the limit speed. That is, when the target torque To is small, the motor control unit 54 limits the motor 15 to a speed that does not reach the maximum speed even when the trigger lever 29 is pulled to the maximum.

  The main body control circuit 30 includes a stop determination unit 55 that determines whether the torque value calculated by the torque calculation unit 45 has reached the target torque. Further, the main body control circuit 30 includes a recording unit 56 that records a torque value at the time of stopping.

Next, the operation of the impact rotary tool 11 of this embodiment will be described.
For example, when the operator tightens a bolt, a screw, or the like, the torque setting unit 51 is operated in advance to set the set torque.

  As shown in FIGS. 1 to 3, when the trigger lever 29 is operated and a trigger switch (not shown) is turned on (step S <b> 10), the control unit 50 sets the set torque set by the torque setting unit 51. The inertia moment set by the inertia moment setting unit 44 is confirmed (step S11).

  Then, the stop determination unit 55 sets a target torque To that is a threshold value based on the set torque set by the torque setting unit 51 (step S12). Next, the motor control unit 54 of the control unit 50 supplies a drive current to the motor 15 to drive the motor 15 (step S13).

  Next, the shaft torque measuring unit 41 of the main body control circuit 30 always acquires the torque detection signal S1 detected by the shaft torque sensor 26 (step S14). The shaft torque measuring unit 41 outputs the torque detection signal S1 for one stroke to the buffer unit 46, which is a temporary storage area, and the buffer unit 46 accumulates the torque detection signal S1 for one stroke (step S15). .

  Further, the rotation angle calculation unit 42 of the main body control circuit 30 acquires the A-phase and B-phase pulse signals (rotary encoder signals) Sa and Sb detected by the rotary encoder 27 (step S16). Incidentally, as shown in FIG. 4B, each of the pulse signals Sa and Sb is a rectangular wave signal having a phase difference of 90 degrees.

  Next, the rotation angle calculation unit 42 calculates a rotation angle (rotation angle) (step S17). Here, an example of the change in the rotation angle will be described. As shown in FIG. 4C, the rotation angle increases due to an impact. Specifically, when the anvil 20 is driven to rotate, first, the rotation play between the anvil 20 and the tip tool 24 and between the tip tool 24 and the fastening member is clogged, and the fastening member and the like are slightly twisted to increase the rotation angle (section). P1). Next, when the fastening member is actually tightened, the rotation angle is further increased (section P2). Then, after the fastening member is not tightened, the torsion of the fastening member and the like is restored, and further, the rotation angle is reduced by starting to generate rotation backlash (section P3).

  Next, the angular acceleration calculation unit 43 calculates a section P2 that is a tightening period in which the fastening member actually tightens (step S18). Here, as the section P2, the angular acceleration calculation unit 43 calculates the section P2 as a section corresponding to the difference between the maximum angle at the previous hit and the maximum angle at the current hit.

  Next, the torque calculation unit 45 sets a torque calculation period based on the section P2 that is the tightening period calculated by the angular acceleration calculation unit 43 (step S19). Next, the torque calculation unit 45 calculates the average value of the torque values in the range of the section P2 in the waveform for one stroke (torque detection signal S1) accumulated in the buffer unit 46 as the measured torque Ts.

  Further, the angular acceleration calculation unit 43 sets the rotation angle calculation period based on the section P2 that is the tightening period (step S21). Next, the angular acceleration calculation unit 43 calculates the angular acceleration α from the data of the rotation angle θ in the range of the section P2. As a method for calculating the angular acceleration α, first, a quadratic approximate curve in the range of the section P2 is created. The equation of the quadratic approximate curve is expressed by the following equation.

Here, since the angular acceleration α is derived by the second derivative of the angle θ, the angular acceleration α can be calculated by the following equation.

Incidentally, the angular acceleration α may vary in the section P2, which is the tightening period, but in order to facilitate the calculation of the angular acceleration α, and based on the idea of obtaining an average value in the section P2, In the section P2, the angular acceleration α is derived as constant.

  Next, the angular acceleration α calculated by the angular acceleration calculation unit 43 is output to the torque calculation unit 45. The torque calculation unit 45 calculates the tightening torque T from the measured torque Ts in the section P2 calculated by itself, the input angular acceleration α, and the rotational moment I input from the inertia moment setting unit 44. The torque T can be calculated by the following equation. However, A, B, and C in the following equations are adjustment (correction) coefficients, and these coefficients may be considered as A = 1, B = 1, and C = 0 if adjustment or the like is not necessary.

Here, considering the case where the tightening torque T calculated for each impact decreases without increasing monotonously, the torque calculation unit 45 calculates the tightening torque T in consideration of these, for example (step S24). At this time, the torque calculation unit 45 calculates the tightening torque T by, for example, a moving average of data for two hits or three hits. However, if the calculated tightening torque variation after the impact is small and the tightening torque T monotonously increases, step S24 may be skipped and the next step may be performed.

  Here, a change in the tightening torque T will be described. As shown in FIG. 5, the anvil 20 is not hit by the hammer 19 immediately after the tightening of the screw by the impact rotary tool 11 is started. For this reason, the output of the shaft torque sensor 26 gradually increases as the fastening of fastening members such as screws and bolts proceeds (indicated by D in FIG. 5). On the other hand, if the hammer 19 hits the anvil 20 due to the torque exceeding a certain value, the impact pulse IP is repeatedly generated. The value calculated for the tightening torque T is updated for each impact pulse IP, and the value is held until the next tightening torque T is calculated. Since it takes time to calculate the tightening torque T, the tightening torque T is updated after a predetermined time from the impact pulse IP. Since the tightening torque T gradually increases as the tightening of the fastening members such as screws and bolts proceeds, the tightening torque value calculated by the torque calculating unit 45 is updated stepwise every time the impact pulse IP occurs. .

  If the calculated tightening torque T is less than the threshold target torque To (step S25: NO), the stop determination unit 55 does not output a stop signal, and thus is repeated from step S14 and step S16. Operation continues.

  When the calculated tightening torque T is equal to or greater than the threshold target torque To (step S25: YES), the stop determination unit 55 instructs the motor control unit 54 to stop the drive current in the motor 15. Is output. Then, the motor control unit 54 to which the stop signal is input from the stop determination unit 55 stops the supply of the drive current to the motor 15 and stops the driving of the motor 15 (step S26). That is, the control unit 50 stops driving the motor 15 when the torque calculated by the torque calculation unit reaches the target torque To. As a result, when the tightening torque T becomes the target torque To, the driving of the impact rotary tool 11 is stopped.

  In addition, the stop determination unit 55 causes the recording unit 56 to record the torque value required for tightening for each work performed by the operator, the time required for tightening, and the like. Therefore, for example, after the work is completed, the operator can obtain the torque value and time for each work.

Next, the effect of this embodiment will be described.
(1) Since the tightening torque T is calculated based on the angular acceleration α and the measured torque Ts, the tightening torque T is estimated from the angular acceleration α or compared to the estimated torque T from the measured torque Ts. The tightening torque T can be calculated with high accuracy. Also, by using hydraulic pressure, impact rotating tools such as impact wrench and impact driver can be made lighter than oil pulses, nut runners, etc. whose impact torque changes relatively slowly. For this reason, torque management is easy and can provide a lightweight tool.

  (2) The torque calculation unit 45 constituting the calculation unit is T = Ts × A−I × α × B + C where T is the tightening torque, Ts is the measurement torque, I is the moment of inertia, and α is the angular acceleration. However, the tightening torque is calculated using A), B, and C are coefficients). Thereby, the tightening torque T can be calculated more reliably.

  (3) The angular acceleration calculation unit 43 that constitutes the calculation unit calculates an approximate curve of the rotation angle measured by the rotary encoder 27 and the rotation angle calculation unit 42 that constitute the rotation angle measurement unit, and differentiates the approximate curve twice. To calculate the angular acceleration α. Thereby, the arithmetic processing by the angular acceleration calculation unit 43 can be facilitated without performing complicated arithmetic processing.

  (4) The angular acceleration calculation unit 43 constituting the calculation unit calculates the approximate curve of the rotation angle as a second order approximate curve, and performs the second derivative of the calculated second order approximate curve, thereby performing the angular acceleration α. Is calculated. This eliminates the need to derive a cubic or higher approximation curve, and facilitates the calculation process by the angular acceleration calculation unit 43 without performing a complicated calculation process.

In addition, you may change the said embodiment as follows.
In the above embodiment, the angular acceleration α in the section P2 that is the tightening period is calculated as constant, but the present invention is not limited to this. For example, the approximate curve of the rotation angle may be calculated in a period longer than the section P2 that is the tightening period. In particular, by calculating the angular acceleration α including information on the angle θ that is several points away from the section P2 (particularly part of the rotation information of the section P1), the angle θ can be reduced even if the section P2 that is the tightening period is shortened. Since information can be obtained, it can contribute to improvement of calculation accuracy. Moreover, you may calculate in a period shorter than the area P2. In particular, since the section P2 is long when the torque is low, the approximate curve is calculated using the period of the decelerating portion of the second half portion except the acceleration portion of the first half portion of the section P2, which can contribute to the improvement of the calculation accuracy. There is a case.

  In the above embodiment, although not particularly mentioned, for example, the contact portion 20a of the anvil 20 may be an elastic body, and torque fluctuation due to an impact at the time of contact between the anvil 20 and the hammer 19 may be reduced. In this case, the measured torque Ts measured by the shaft torque measuring unit may be derived as a peak value within the predetermined time. This is because the angular acceleration α can be expected to be very small, so that it can be considered that the tightening torque T≈the measured torque Ts.

In addition, as the angular acceleration α, a configuration using an average value of measured values in the section P2 that is a predetermined period (tightening period) may be employed.
In the above embodiment, the approximate curve of the angle θ is derived as a quadratic approximate curve, but may be a cubic or higher order. An example when derived as a quartic approximate curve is shown below.

  As a method for calculating the angular acceleration α, a fourth-order approximate curve in the range of the section P2 is created. The equation of the quaternary approximation curve is expressed by the following equation.

Here, since the angular acceleration α is derived by the second derivative of the angle θ, the angular acceleration α can be calculated by the following equation.

In this way, since the change in the angle θ can be obtained with higher accuracy by using a third-order or higher order approximate curve, the angular acceleration α can be calculated with higher accuracy.

  In the above embodiment, the angular acceleration α is calculated using an approximate expression (approximate curve of the angle θ), but the present invention is not limited to this. For example, as shown in FIG. 6, the speed change may be calculated using the speed v1 between the point X1 and the point X2 and the speed v2 between the point X2 and the point X3. Specifically, the angular acceleration α is calculated by the following equation.

The motor 15 may be a DC motor or an AC motor other than the brush motor or the brushless motor.

  The drive source of the impact rotary tool 11 is not limited to a motor, and may be a solenoid, for example. Moreover, not only an electric drive source such as a motor or a solenoid, but also a hydraulic drive source may be used.

The impact rotary tool 11 may be a non-rechargeable AC impact rotary tool or an air impact rotary tool.
-As a torque sensor, the structure which adhere | attaches and fixes a strain gauge to the main axis | shaft 21, and acquires data by a slip ring or non-contact communication may be employ | adopted.

In the above embodiment, the handheld type capable of gripping the impact rotary tool is used, but the present invention is not limited to this.
-It is good also as a tip attachment attached to an impact rotary tool instead of an impact rotary tool. For example, as shown in FIG. 7, the tip attachment 70 includes a through shaft 72 that passes through the housing 71. One end of the penetrating shaft 72 is attached to the chuck portion 13a of the impact rotary tool 11, for example, so that the rotation of the main shaft 21 is transmitted. The tip tool 24 is attached to the other end of the through shaft 72. Further, the housing 71 of the attachment 70 is fixed by the body portion 13 of the impact rotary tool 11 and the fixing member 73 in order to suppress the accompanying rotation accompanying the rotation of the through shaft 72.

  A shaft torque sensor 26 and a rotary encoder 27 are attached to the through shaft 72 constituting the shaft portion. The shaft torque sensor 26 and the rotary encoder 27 are electrically connected to an arithmetic circuit 74 housed in the housing 71. The arithmetic circuit 74 includes, for example, the shaft torque measurement unit 41, the rotation angle calculation unit 42, the angular acceleration calculation unit 43, the inertia moment setting unit 44, the torque calculation unit, the buffer unit 46, the stop determination unit 55, and the recording unit in the above embodiment. 56. Therefore, for example, when the tightening torque T calculated by the stop determination unit 55 in the arithmetic circuit 74 reaches the target torque To, a stop signal is issued to the main body control circuit 30 (the motor control unit 54) in the impact rotary tool 11. Further, the set torque information set by the torque setting unit 51 can be output to the arithmetic circuit 74 from the impact rotary tool 11 side.

  The configuration of the tip attachment 70 is an example, and includes at least a rotary encoder 27 and a shaft torque sensor 26. If the information can be output to the main body control circuit 30 on the impact rotary tool 11, the tip attachment 70 is appropriately changed. Also good.

-You may combine the said embodiment and said each modification suitably.
Next, a technical idea that can be grasped from the above embodiment and another example will be added below.
(Appendix 1)
In the tip attachment for impact rotary tools according to claim 8,
When the tightening torque is T, the measurement torque is Ts, the moment of inertia is I, and the angular acceleration is α,
T = Ts × A−I × α × B + C (where A, B, and C are coefficients)
A tip attachment for an impact rotary tool, characterized in that the tightening torque is calculated using a screw.

(Appendix 2)
In the tip attachment for impact rotary tools according to claim 8 or appendix 1,
The calculation unit calculates an angular curve of the rotation angle measured by the rotation angle measurement unit, and calculates the angular acceleration by performing a second differentiation of the approximation curve. Tip attachment.

(Appendix 3)
In the tip attachment for impact rotary tools described in the above supplementary note 2,
The calculation unit calculates the angular acceleration by calculating the approximate curve of the rotation angle as a secondary approximate curve, and calculating the angular acceleration by performing a second differentiation of the calculated approximate curve of the second order. Tip attachment for tools.

(Appendix 4)
In the tip attachment for impact rotary tools according to claim 8 or appendix 1,
The calculation unit uses an average value of values within a predetermined period as the measured torque and the angular acceleration, respectively, and the tip attachment for an impact rotary tool.

(Appendix 5)
In the tip attachment for impact rotary tools described in the above supplementary note 4,
The calculation unit calculates the approximate curve of the rotation angle in a period including at least a part of a tightening period corresponding to a difference between the maximum angle at the time of the last hit and the maximum angle at the time of the current hit. Tip attachment for impact rotating tools.

(Appendix 6)
In the tip attachment for impact rotary tools according to claim 8 or appendix 1,
The tip attachment for an impact rotary tool, wherein the measured torque measured by the torque measuring unit is a peak value within the predetermined time.

DESCRIPTION OF SYMBOLS 11 ... Impact rotary tool, 17 ... Impact force generation part, 24 ... Tip tool, 26 ... Shaft torque sensor which comprises a torque measurement part, 27 ... Rotary encoder which comprises a rotation angle measurement part, 41 ... The torque measurement part is comprised Axial torque measuring unit, 42... Rotation angle calculating unit constituting rotation angle measuring unit, 43... Angular acceleration calculating unit constituting calculating unit, 45... Torque calculating unit constituting calculating unit, 50. Acceleration, T ... Tightening torque, Ts ... Measured torque.

Claims (8)

An impact force generator that generates impact force by changing the power of the drive source to pulsed torque;
A shaft portion for transmitting a pulsed torque to the tip tool by the generated impact force;
A torque measurement unit for measuring a measurement torque which is a torque applied to the shaft part;
A rotation angle measurement unit for measuring the rotation angle of the shaft part;
An approximate curve of the rotation angle is calculated for a predetermined period including at least a part of the tightening period corresponding to the difference between the maximum angle at the last hit and the maximum angle at the current hit, and the calculated rotation angle A calculation unit that calculates an angular acceleration based on the approximate curve and calculates a tightening torque based on the angular acceleration and the measured torque;
An impact rotary tool comprising: a control unit that controls the drive source based on the tightening torque.   In the impact rotary tool according to claim 1,
  The impact rotary tool characterized in that the calculation unit calculates the tightening torque based on the measured torque measured in the predetermined period. In the impact rotary tool according to claim 1 or 2 ,
The calculation unit, when the tightening torque is T, the measurement torque is Ts, the moment of inertia around the rotation axis of the tip tool is I, and the angular acceleration is α,
T = Ts × A−I × α × B + C (where A, B, and C are coefficients)
An impact rotary tool characterized in that the tightening torque is calculated using a tool. In the impact rotary tool according to any one of claims 1 to 3 ,
The calculating unit, a rotary impact tool and calculates the angular acceleration by performing the second derivative of the approximate curve before Symbol rotation angle. In the impact rotary tool according to claim 4 ,
The calculation unit calculates the angular acceleration by calculating the approximate curve of the rotation angle as a secondary approximate curve, and calculating the angular acceleration by performing a second differentiation of the calculated approximate curve of the second order. tool. In the impact rotary tool according to any one of claims 1 to 3 ,
The calculating unit is configured as a measured torque and the angular acceleration, rotary impact tool, which comprises using the mean value of the values in each within the predetermined time period. In the impact rotary tool according to any one of claims 1 to 3 ,
Measured torque measured by the torque measuring unit, the impact rotary tool, wherein the a peak value within a predetermined period. A torque measurement unit for measuring a measurement torque, which is a torque applied to a shaft part for transmitting an impact force generated by an impact rotary tool to a tip tool;
A rotation angle measurement unit for measuring the rotation angle of the shaft part;
An approximate curve of the rotation angle is calculated for a predetermined period including at least a part of the tightening period corresponding to the difference between the maximum angle at the last hit and the maximum angle at the current hit, and the calculated rotation angle A tip attachment for an impact rotary tool, comprising: a calculation unit that calculates an angular acceleration based on an approximate curve and calculates a tightening torque based on the angular acceleration and the measured torque.