Rotary impact tool, torque estimation method, and program

Abstract

To provide an impact rotary tool which can accurately estimate a torque value.SOLUTION: An impact rotary tool 100 includes a driving part 1, a driving shaft 21, a hammer 22, an anvil 23, a moving amount detection part 3, and a torque estimation part. The driving part 1 performs rotation operation. The driving shaft 21 is rotated by the driving part 1. The hammer 22 is fit to the outer periphery of the driving shaft 21 so as to be movable in a shaft direction D1 of the driving shaft 21 and be rotatable in a rotation direction of the driving shaft 21. Impact in the rotation direction is applied to the anvil 23 by the hammer 22. When the impact is applied to the anvil 23 by the hammer 22, the moving amount detection part 3 detects a parameter relating to a hammer moving amount of moving so as to be separated from the anvil 23 in the shaft direction D1 from a position to which the impact is applied by the hammer 22. The torque estimation part estimates a torque value generated by impact, on the basis of the parameter relating to at least the hammer moving amount.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure generally relates to a rotary impact tool, a torque estimation method, and a program, and more particularly to a rotary impact tool, a torque estimation method, and a program for estimating a torque value. [Background technology]

[0002] Patent Document 1 discloses a rotary impact tool including a rotary drive unit, an output shaft, a calculation means, a rotational speed setting means, and a control means. The rotary drive unit rotates a hammer via the drive shaft. A rotational force is applied to the output shaft by striking with the hammer. The calculation means calculates a tightening torque from the striking motion. The rotational speed setting means changes the rotational speed of the rotary drive unit. The control means rotates the rotary drive unit at the rotational speed set by the rotational speed setting means, and stops the rotary drive unit when the tightening torque calculated by the calculation means is equal to or greater than a tightening torque value preset by the torque setting means. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2005-324265 Summary of the Invention [Problem to be solved by the invention]

[0004] The rotary impact tool described above calculates a tightening torque value (torque value) based on the rotation speed of the rotary drive unit and the number of strikes of the hammer. However, it is thought that the tightening torque value may differ depending on the type of fastening part (screw, bolt, nut, etc.) even when the number of strikes of the hammer and the rotation speed are the same. In other words, there is a demand for a rotary impact tool that can accurately estimate the tightening torque value.

[0005] An object of the present disclosure is to provide a rotary impact tool, a torque estimation method, and a program that can accurately estimate a torque value. [Means for solving the problem]

[0006] A rotary impact tool according to one aspect of the present disclosure includes a drive unit, a drive shaft, a hammer, an anvil, a movement amount detection unit, and a torque estimation unit. , a control unit, and The drive unit performs a rotational operation. The drive shaft is rotated by the drive unit. The hammer is fitted to the outer periphery of the drive shaft so as to be movable in the axial direction of the drive shaft and rotatable in the rotational direction of the drive shaft. The anvil is struck by the hammer in the rotational direction. The movement amount detection unit detects a parameter related to a hammer movement amount, which is the amount by which the hammer moves away from the anvil along the axial direction from the position where the hammer struck, when the hammer strikes the anvil. The torque estimation unit estimates a torque value generated by the strike based on at least the parameter. The control unit performs vector control of the drive unit. A torque current is supplied to the drive unit through the vector control of the control unit. The movement amount detection unit detects a fluctuation amount of the torque current from when the hammer strikes the anvil until the next time the hammer strikes the anvil. The movement amount detection unit detects the hammer movement amount itself as the parameter based on the fluctuation amount.

[0007] A torque estimation method according to one aspect of the present disclosure is a torque estimation method for estimating a torque value generated by an impact of a rotary impact tool including a drive unit, a drive shaft, a hammer, and an anvil. The drive unit performs a rotational operation. The drive shaft is rotated by the drive unit. The hammer is fitted to the outer periphery of the drive shaft so as to be movable in the axial direction of the drive shaft and rotatable in the rotational direction of the drive shaft. The anvil is struck in the rotational direction by the hammer. The torque estimation method includes a movement amount detection step and a torque estimation step. , control step and, The movement amount detection step detects a parameter related to a hammer movement amount, which is a movement amount of the hammer along the axial direction away from the anvil from a position where the hammer applied the strike when the hammer applied the strike to the anvil. The torque estimation step estimates a torque value generated by the strike based on at least the parameter. A torque current is supplied to the drive unit by vector control in the control step. In the movement amount detection step, a fluctuation amount of the torque current from one impact of the hammer on the anvil to the next impact is detected. In the movement amount detection step, the hammer movement amount itself is detected as the parameter based on the fluctuation amount.

[0008] A program according to one aspect of the present disclosure is a program for causing a computer system to execute the torque estimation method. [Effects of the Invention]

[0009] The present disclosure has the advantage of being able to accurately estimate torque values. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a block diagram showing a schematic configuration of a rotary impact tool according to this embodiment. [Figure 2] FIG. 2 is a diagram showing a schematic configuration of the rotary impact tool. [Figure 3] FIG. 3 is an explanatory diagram illustrating the change over time of the torque current in the rotary impact tool, and the change over time of the calculated value and the target value of the rotation speed of the drive unit. [Figure 4] FIG. 4 is a flowchart showing the torque estimation method. DETAILED DESCRIPTION OF THE INVENTION

[0011] (Present embodiment) (1) Overview Hereinafter, an outline of the rotary impact tool according to this embodiment will be described with reference to FIGS. 1 and 2. FIG.

[0012] 1 and 2, the rotary impact tool 100 according to this embodiment includes a drive unit 1, a drive shaft 21, a hammer 22, an anvil 23, a movement amount detection unit 3, and a torque estimation unit 5. It is assumed that an operator uses the rotary impact tool 100 for fastening work to fasten a fastening part (screw, bolt, nut, etc.) to an object to be fastened (electrical appliance, furniture, etc.).

[0013] The drive unit 1 performs a rotational operation. The drive shaft 21 is rotated by the drive unit 1. The hammer 22 is fitted to the outer periphery of the drive shaft 21 so as to be movable in the axial direction of the drive shaft 21 and rotatable in the rotational direction of the drive shaft 21. The anvil 23 is struck by the hammer 22 in the rotational direction of the drive shaft 21.

[0014] The movement amount detection unit 3 detects a parameter related to the amount of hammer movement, which is the amount of movement of the hammer 22 from the position where the hammer 22 applied a strike to the anvil 23 along the axial direction D1 (see FIG. 2) of the drive shaft 21 so as to move away from the anvil 23. The torque estimation unit 5 estimates the torque value generated by the strike based on at least the parameter detected by the movement amount detection unit 3. The "torque value" here is a value that indicates the magnitude of the torque generated by the strike, i.e., a value that indicates the magnitude of the torque applied to the fastening part.

[0015] In general, even if the number of strikes and rotation speed of the hammer 22 are the same, the degree to which the anvil 23 rotates due to the strikes applied by the hammer 22 will differ depending on the type of fastening part (for example, metal screws or wood screws), and it is thought that the torque value generated by the strikes will also differ. Therefore, when estimating the torque value based on the number of strikes or rotation speed of the hammer 22, it is not possible to take into account the difference in torque value depending on the type of fastening part, making it difficult to accurately estimate the torque value.

[0016] However, in the rotary impact tool 100 of this embodiment, the torque estimation unit 5 estimates the torque value generated by the impact based at least on the hammer movement distance. When the hammer 22 strikes the anvil 23, the anvil 23 moves away from the strike due to the repulsive force of the anvil 23 in response to the strike. The repulsive force of the anvil 23 in response to the strike varies depending on the degree of rotation of the anvil 23, and therefore the hammer movement distance varies depending on the degree of rotation of the anvil 23. Therefore, the rotary impact tool 100 of this embodiment can estimate the torque value by taking into account differences in the degree of rotation of the anvil 23 depending on the type of fastening part. In other words, the rotary impact tool 100 of this embodiment has the advantage of being able to accurately estimate the torque value.

[0017] (2) Detailed configuration (2-1) Overall structure The detailed configuration of this embodiment will be described below with reference to FIGS.

[0018] As shown in Figures 1 and 2, the impact rotary tool 100 further includes a drive unit 1, an impact mechanism 2, a movement amount detection unit 3, a rotational speed detection unit 4, a torque estimation unit 5, a control unit 6, a reduction mechanism 91, an output shaft 92, and a holding unit 93.

[0019] In the following description, the axial direction D1 (see FIG. 2) of the drive shaft 21 described later is defined as the front-rear direction. The side of the anvil 23 described later as viewed from the hammer 22 described later is defined as the front, and the side of the hammer 22 as viewed from the anvil 23 is defined as the rear.

[0020] The impact rotary tool 100 preferably includes a computer system. The computer system primarily comprises a processor and memory as hardware components. The processor executes a program stored in the computer system's memory to realize at least some of the functions of the movement amount detection unit 3, rotational speed detection unit 4, torque estimation unit 5, and control unit 6 of the present disclosure. The computer system primarily comprises a processor that operates according to the program. The processor may be of any type, as long as it can realize the functions by executing the program. The processor may be composed of one or more electronic circuits, including a semiconductor integrated circuit (IC) or a large-scale integration (LSI). While ICs and LSIs are used here, the names may vary depending on the degree of integration, and may also be referred to as system LSIs, very large-scale integrations (VLSIs), or ultra-large-scale integrations (ULSIs). Field-programmable gate arrays (FPGAs), which are programmed after the LSI is manufactured, or reconfigurable logic devices, which can reconfigure the connections within the LSI or set up circuit blocks within the LSI, can also be used for the same purpose. The electronic circuits may be integrated on a single chip or may be provided on multiple chips, and the multiple chips may be integrated into a single device or may be provided on multiple devices.

[0021] (2-2) Drive unit The drive unit 1 performs a rotational operation. More specifically, the drive unit 1 is driven by power supplied from a power supply unit B1 (see FIG. 2 ) to perform the rotational operation. As an example, the power supply unit B1 is a rechargeable battery pack that is detachably attached to the rotary impact tool 100. The power supply unit B1 is not a component of the rotary impact tool 100. However, the rotary impact tool 100 may include the power supply unit B1 as a component.

[0022] The drive unit 1 is, for example, a brushless motor. In particular, the drive unit 1 of this embodiment is a synchronous motor, more specifically, a permanent magnet synchronous motor (PMSM). The drive unit 1 includes a rotor having a rotating shaft and a permanent magnet, and a stator having armature windings for three phases (U phase, V phase, and W phase).

[0023] The torque and rotation speed of the drive unit 1 change according to the control by the control unit 6. The control unit 6 controls the torque and rotation speed of the drive unit 1 by controlling the motor current flowing through the drive unit 1 using the power supplied from the power supply unit B1. In this embodiment, the control unit 6 performs vector control of the drive unit 1. More specifically, the control unit 6 in this embodiment decomposes the motor current into a torque current that generates torque and an excitation current that generates magnetic flux, and performs vector control that controls each current component independently. That is, the torque current and excitation current are supplied to the drive unit 1 by the vector control of the control unit 6.

[0024] (2-3) Impact mechanism The rotary impact tool 100 of this embodiment performs a tightening operation while performing an impact operation using the impact mechanism 2. During the impact operation, the impact mechanism 2 generates an impact force based on the power of the drive unit 1, and the impact force acts on the tool bit C1 (see FIG. 2).

[0025] As shown in FIGS. 1 and 2, the impact mechanism 2 includes a drive shaft 21, a hammer 22, an anvil 23, and an elastic member 24.

[0026] The drive shaft 21 is mechanically connected to the rotating shaft of the drive unit 1 via a speed reduction mechanism 91. The speed reduction mechanism 91 converts the rotation speed and torque of the rotating shaft of the drive unit 1 into the rotation speed and torque required for screw turning. The torque of the rotating shaft of the drive unit 1 is transmitted to the drive shaft 21 via the speed reduction mechanism 91. As a result, the drive shaft 21 rotates. The drive shaft 21 is a so-called spindle.

[0027] The hammer 22 is fitted onto the outer periphery of the drive shaft 21 so as to be movable in the axial direction D1 of the drive shaft 21 and rotatable in the rotational direction of the drive shaft 21. When the rotational force of the drive shaft 21 is transmitted to the hammer 22, the hammer 22 rotates integrally with the drive shaft 21 in the rotational direction of the drive shaft 21.

[0028] The elastic member 24 is disposed between the speed reduction mechanism 91 and the hammer 22. A force is applied to the hammer 22 by the elastic member 24 toward the anvil 23 along the axial direction D1 of the drive shaft 21. In other words, the hammer 22 is biased by the elastic member 24 toward the anvil along the axial direction D1 of the drive shaft 21. The elastic member 24 in this embodiment is, for example, a conical coil spring.

[0029] The anvil 23 has an engagement portion that engages with the hammer 22 in the rotational direction. When the hammer 22 and the anvil 23 are engaged with each other, the rotational force of the hammer 22 is transmitted to the anvil 23. This causes the anvil 23 to rotate.

[0030] The output shaft 92 of this embodiment is formed integrally with the anvil 23. A holding portion 93 is provided at the tip of the output shaft 92. The output shaft 92 transmits the rotational force of the anvil 23 to the holding portion 93.

[0031] The holder 93 holds the tool bit C1. More specifically, the tool bit C1 is detachably attached to the holder 93. The tool bit C1 may be integrally formed with the holder 93. In this embodiment, the output shaft 92 and the tool bit C1 rotate together with the anvil 23.

[0032] The tool bit C1 is, for example, a driver bit. The tool bit C1 is fitted to a fastening part. When the tool bit C1 is rotated while fitted to the fastening part, it becomes possible to perform an operation such as tightening the fastening part. In this embodiment, the tool bit C1 is not included in the configuration of the impact rotary tool 100. However, the tool bit C1 may be included in the configuration of the impact rotary tool 100.

[0033] The impact mechanism 2 performs an impact operation when an impact condition related to the magnitude of the rotational force of the hammer 22 applied to the anvil 23 is satisfied. The impact operation is an operation in which the hammer 22 applies a striking force to the anvil 23. In this embodiment, the impact condition is that the rotational force of the hammer 22 is equal to or greater than a predetermined value. As the rotational force of the hammer 22 increases, the component of the force generated between the hammer 22 and the anvil 23 that moves the hammer 22 backward also increases. When the rotational force of the hammer 22 exceeds a predetermined value, the hammer 22 moves backward while compressing the elastic member 24. Thereafter, the hammer 22 receives a return force from the elastic member 24 and moves forward while rotating. Then, when the drive shaft 21 rotates a predetermined amount (e.g., approximately half a rotation), the hammer 22 collides with the anvil 23. In other words, the anvil 23 is struck by the hammer 22 in the rotational direction every time the drive shaft 21 rotates a predetermined amount. In the present disclosure, "moving backward" means moving backward along the fore-and-aft direction, and "moving forward" means moving forward along the fore-and-aft direction.

[0034] In this way, in the impact mechanism 2, the hammer 22 repeatedly strikes the anvil 23 in the rotational direction. The torque generated by this strike makes it possible to tighten the fastening parts more strongly than in the case where there is no collision.

[0035] (2-4) Movement amount detection unit The movement amount detection unit 3 of this embodiment detects the hammer movement amount itself as a parameter related to the hammer movement amount. That is, the movement amount detection unit 3 of this embodiment detects the hammer movement amount by which the hammer 22 moves away from the anvil 23 along the axial direction D1 from the position where the hammer 22 applied the strike to the anvil 23 when the hammer 22 applied the strike to the anvil 23. More specifically, the hammer movement amount indicates how far the hammer 22 retreats along the axial direction D1 from the position where the hammer 22 applied the strike to the anvil 23.

[0036] To explain how the movement amount detection unit 3 of this embodiment detects the hammer movement amount, we will first explain the fluctuation amount A1 of the torque current X1 supplied to the drive unit 1 by the vector control of the control unit 6. Fig. 3 shows the change over time of the torque current X1 supplied to the drive unit 1 by the vector control of the control unit 6 while the rotary impact tool 100 is performing a tightening operation while performing an impact operation using the impact mechanism 2.

[0037] Generally, the torque current X1 changes depending on the magnitude of the load applied to the drive unit 1. That is, if the load applied to the drive unit 1 increases, the torque current X1 increases, and conversely, if the load applied to the drive unit 1 decreases, the torque current X1 decreases. Therefore, as shown in Fig. 3 , the torque current X1 increases when the hammer 22 strikes the anvil 23, and decreases immediately after the hammer 22 has moved back to its rearmost position. This fluctuation is repeated every time the hammer 22 strikes the anvil 23.

[0038] More specifically, the fluctuation of the torque current X1 when the hammer 22 strikes the anvil 23 at time T1a and then strikes the anvil 23 again at time T2a will be described as an example with reference to Fig. 3. Time T1b shown in Fig. 3 is the timing when the hammer 22 has moved farthest backward.

[0039] Before the hammer 22 strikes the anvil 23 at time T1a, the hammer 22 rotates while disengaged from the anvil 23. Because the hammer 22 and the anvil 23 are no longer engaged, the load on the drive unit 1 decreases, and the torque current X1 decreases. Thereafter, at time T1a, the hammer 22 strikes the anvil 23, and the hammer 22 and the anvil 23 are no longer engaged. Between time T1a and time T1b, the hammer 22 moves backward while compressing the elastic member 24. While the hammer 22 is moving backward, the drive unit 1 supplies energy to the hammer 22, so the load on the drive unit 1 increases and the torque current X1 increases. Between time T1b and time T2a, the hammer 22 moves forward while rotating while disengaged from the anvil 23. While the hammer 22 is moving forward, the driver 1 does not supply energy to the hammer 22, so the load on the driver 1 decreases, and the torque current X1 decreases. Thereafter, at time T2a, the hammer 22 strikes the anvil 23 again, and then the hammer 22 moves backward while compressing the elastic member 24. While the hammer 22 is moving backward, the driver 1 supplies energy to the hammer 22, so the load on the driver 1 increases, and the torque current X1 increases. As described above, the torque current X1 when the hammer 22 strikes the anvil 23 at time T1a is at a minimum value V1a, and the torque current X1 when the hammer 22 is at its most backward position at time T1b is at a maximum value V1b. Furthermore, the torque current X1 when the hammer 22 strikes the anvil 23 at time T2a is at a minimum value V2a. While the rotary impact tool 100 is performing a fastening operation while the impact mechanism 2 is performing an impact operation, the torque current X1 repeats the above fluctuations every time the hammer 22 strikes the anvil 23.

[0040] In this embodiment, the amount of fluctuation A1 of the torque current X1 from when the hammer 22 strikes the anvil 23 at time T1a until when the hammer 22 strikes the anvil 23 again at time T2a is defined as the difference between the minimum value V1a at time T1a and the maximum value V1b at time T1b. In other words, in this embodiment, the amount of fluctuation A1 of the torque current X1 from when the hammer 22 strikes the anvil 23 until when the hammer 22 strikes the anvil 23 again is defined as the difference between the minimum value when the hammer 22 strikes the anvil 23 and the maximum value when the hammer 22 is moved all the way back.

[0041] While the hammer 22 is moving backward while compressing the elastic member 24, the driving unit 1 continues to apply force to the hammer 22. The greater the amount of hammer movement of the hammer 22 due to the impact that the hammer 22 delivers to the anvil 23, the greater the load on the driving unit 1. That is, the greater the amount of hammer movement of the hammer 22 due to the impact that the hammer 22 delivers to the anvil 23, the greater the fluctuation amount A1 of the torque current X1. That is, the fluctuation amount A1 of the torque current X1 changes depending on the amount of hammer movement of the hammer 22 due to the impact that the hammer 22 delivers to the anvil 23 at time T1a. In other words, the fluctuation amount A1 of the torque current X1 is correlated with the amount of hammer movement of the hammer 22 due to the impact that the hammer 22 delivers to the anvil 23 at time T1a.

[0042] As described above, the movement amount detection unit 3 of this embodiment detects the amount of fluctuation A1 in the torque current X1 from when the hammer 22 strikes the anvil 23 until the next strike, and detects the amount of hammer movement itself as a parameter related to the amount of hammer movement based on the detected amount of fluctuation A1 in the torque current X1. More specifically, the movement amount detection unit 3 of this embodiment detects the amount of fluctuation A1 in the torque current X1 from time T1a when the hammer 22 strikes the anvil 23 to time T2a when the next strike is struck, and detects the amount of hammer movement due to the strike by the hammer 22 to the anvil 23 at time T1a based on the detected amount of fluctuation A1 in the torque current X1.

[0043] Specifically, the movement amount detection unit 3 of this embodiment has a current sensor that detects the torque current supplied to the drive unit 1 by the vector control of the control unit 6. In this embodiment, the current sensor of the movement amount detection unit 3 is integrated with the current sensor used for the vector control. With the above configuration, the rotary impact tool 100 has the advantage that it does not need to be provided with an additional sensor that detects the hammer movement amount, and the torque value can be estimated more accurately.

[0044] The movement amount detection unit 3 of this embodiment detects the fluctuation amount A1 of the torque current X1 multiple times during one operation, and detects the hammer movement amount when the fluctuation amount A1 of the torque current X1 indicates an increasing trend during the multiple detections. More specifically, the movement amount detection unit 3 of this embodiment detects the fluctuation amount A1 of the torque current X1 each time the hammer 22 strikes the anvil 23 during one fastening operation, and detects the hammer movement amount when the fluctuation amount A1 of the torque current X1 indicates an increasing trend. Generally, at the start of a fastening operation using the impact rotary tool 100, the parts to be fastened have not yet been fastened, so the anvil 23 rotates integrally with the parts to be fastened, and the rotation angle of the parts to be fastened increases each time the hammer 22 strikes the anvil 23. Therefore, at the start of the fastening operation, the fluctuation amount A1 of the torque current X1 may become large even though the hammer movement amount is small. When the fluctuation amount A1 of the torque current X1 becomes large, the fluctuation amount A1 of the torque current X1 tends to decrease until the tightening part is tightened to a certain extent. However, as time passes from the start of the tightening operation using the impact rotary tool 100 and the tightening part is tightened to a certain extent, the rotation angle of the tightening part each time the hammer 22 strikes the anvil 23 decreases. As a result, the repulsive force of the anvil 23 against the strike increases, increasing the hammer movement amount, and the fluctuation amount A1 of the torque current X1 for each strike tends to increase. With the above configuration, the hammer movement amount can be detected based on the fluctuation amount A1 of the torque current X1 at the point when the rotation angle of the tightening part each time a strike is struck decreases. In other words, the above configuration has the advantage of being able to more accurately detect the hammer movement amount based on the fluctuation amount A1 of the torque current X1.

[0045] The movement amount detection unit 3 of this embodiment determines that the fluctuation amount A1 of the torque current X1 is increasing if the fluctuation amount A1 of the torque current X1 increases a predetermined number of times in multiple detections. More specifically, the movement amount detection unit 3 of this embodiment stores history information of the fluctuation amount A1 of the torque current X1 detected each time the hammer 22 strikes the anvil 23, and determines that the fluctuation amount A1 is increasing if the fluctuation amount A1 of the torque current X1 is determined to be greater than the fluctuation amount A1 of the torque current X1 in the previous strike a predetermined number of times in succession. The "predetermined number" here is empirically set, and is, for example, three times. In other words, if the "predetermined number" is set to three times, the movement amount detection unit 3 of this embodiment determines that the fluctuation amount A1 is increasing if the fluctuation amount A1 of the torque current X1 detected in three consecutive strikes increases consecutively. Note that the "predetermined number" in the present disclosure is not limited. This configuration has the advantage that the amount of hammer movement can be detected more accurately regardless of the material of the fastening part or fastening member.

[0046] (2-5) Rotational speed detection unit The rotation speed detection unit 4 detects the rotation speed of the hammer 22. In this embodiment, the rotation speed detection unit 4 detects the rotation speed of the hammer 22 based on the rotation speed of the drive unit 1. The rotation speed detection unit 4 detects the excitation current supplied to the drive unit 1 by the control unit 6, and calculates the rotation speed of the drive unit 1 based on the detected excitation current. In other words, the rotation speed detection unit 4 has a current sensor that detects the excitation current supplied to the drive unit 1 by the control unit 6.

[0047] Fig. 3 shows the time changes of the calculated value X2 of the rotation speed of the drive unit 1 calculated by the rotation speed detection unit 4 and the target value X3 of the rotation speed of the drive unit 1 vector-controlled by the control unit 6 while the impact rotary tool 100 is performing a tightening operation while performing an impact action using the impact mechanism 2. The set value R1 shown in Fig. 3 is a value of the rotation speed that is set in advance by the operator so as to be suitable for the tightening operation performed by the impact rotary tool 100. The control unit 6 calculates the target value X3 so that the rotation speed of the drive unit 1 reaches the set value R1.

[0048] 3, the calculated value X2 of the rotation speed of the drive unit 1 fluctuates each time the hammer 22 strikes the anvil 23. Therefore, the rotation speed detection unit 4 of this embodiment detects the rotation speed of the hammer 22 based on the calculated value X2 of the rotation speed of the drive unit 1, thereby making it possible to more accurately detect the rotation speed of the hammer 22, which fluctuates each time the hammer 22 strikes the anvil 23.

[0049] (2-6) Torque estimation section The amount of movement of the hammer 22 when it strikes the anvil 23 is determined by the physical parameters of the impact mechanism 2, the rotational speed of the hammer 22, and the torque generated in the anvil 23 by the strike. The "physical parameters of the impact mechanism 2" here refer to the materials or dimensions of the drive shaft 21, hammer 22, anvil 23, and elastic member 24 of the impact mechanism 2. In other words, the "physical parameters of the impact mechanism 2" do not change depending on the object or part to be fastened, but are uniquely determined for each rotary impact tool 100.

[0050] As described above, the torque estimation unit 5 estimates a torque value indicating the magnitude of torque generated in the anvil 23 due to the impact of the hammer 22 on the anvil 23, based on parameters related to the hammer movement amount detected by the movement amount detection unit 3, the rotational speed detected by the rotational speed detection unit 4, and physical parameters of the impact mechanism 2. In this embodiment, the torque estimation unit 5 estimates a torque value indicating the magnitude of torque generated in the anvil 23 due to the impact of the hammer 22 on the anvil 23, based on the hammer movement amount detected by the movement amount detection unit 3, the rotational speed detected by the rotational speed detection unit 4, and physical parameters of the impact mechanism 2. More specifically, the torque estimation unit 5 of this embodiment performs machine learning of torque values ​​in advance using both the hammer movement amount and the rotational speed of the hammer 22 as feature quantities, and estimates the torque value based on the hammer movement amount detected by the movement amount detection unit 3 and the rotational speed detected by the rotational speed detection unit 4.

[0051] (3) Operation Next, a torque estimation method for estimating a torque value indicating the magnitude of torque generated by the impact of the rotary impact tool 100 will be described with reference to FIG.

[0052] As shown in FIG. 4, the torque estimation method includes a fluctuation amount detection step ST1, a determination step ST2, a movement amount detection step ST3, a rotation speed detection step ST4, and a torque estimation step ST5.

[0053] After the worker starts the tightening operation using the impact rotary tool 100, in a fluctuation detection step ST1, the movement amount detection unit 3 detects a fluctuation amount A1 of the torque current X1 from when the hammer 22 strikes the anvil 23 to when the next strike is made. More specifically, the movement amount detection unit 3 detects the fluctuation amount A1 of the torque current X1 from when the hammer 22 strikes the anvil 23 to when the next strike is made, and stores the fluctuation amount A1 of the torque current X1 as history information.

[0054] Then, in determination step ST2, movement amount detection unit 3 determines whether fluctuation amount A1 of torque current X1 shows an increasing trend in multiple detections. In determination step ST2 of this embodiment, movement amount detection unit 3 determines whether fluctuation amount A1 of torque current X1 increases a predetermined number of times consecutively in multiple detections. Determination step ST2 of this embodiment includes a first determination step ST2a, a second determination step ST2b, and a third determination step ST2c.

[0055] In the first determination step ST2a, the movement amount detection unit 3 determines whether both the fluctuation amount A1 of the torque current X1 at the immediately preceding impact and the fluctuation amount A1 of the torque current X1 at the previous impact are stored as history information. The "immediately preceding impact" here refers to the impact at which the fluctuation amount A1 of the torque current X1 was detected in the fluctuation amount detection step ST1 performed before the current determination step ST2. The "previous impact" here refers to the impact immediately before the "immediately preceding impact" among the impacts repeatedly applied to the anvil 23.

[0056] If only the fluctuation amount A1 of the torque current X1 at the immediately preceding impact is stored and the fluctuation amount A1 of the torque current X1 at the previous impact is not stored (ST2a: No), the movement amount detection unit 3 again detects the fluctuation amount A1 of the torque current X1 from when the hammer 22 strikes the anvil 23 until the next impact (ST1). In other words, if only the fluctuation amount A1 of the torque current X1 at the immediately preceding impact is stored and the fluctuation amount A1 of the torque current X1 at the previous impact is not stored (ST2a: No), the movement amount detection unit 3 detects the fluctuation amount A1 of the torque current X1 at the next impact. Here, the phrase "only the fluctuation amount A1 of the torque current X1 at the immediately preceding impact is stored and the fluctuation amount A1 of the torque current X1 at the previous impact is not stored" assumes a case where, after the operator starts the tightening operation, the fluctuation amount A1 of the torque current X1 at the first impact is detected in the fluctuation amount detection step ST1 and the process proceeds to the first determination step ST2a.

[0057] On the other hand, if both the fluctuation amount A1 of the torque current X1 at the immediately preceding impact and the fluctuation amount A1 of the torque current X1 at the previous impact are stored (ST2a: Yes), the movement amount detection unit 3 performs a second judgment step ST2b to judge whether the fluctuation amount A1 of the torque current X1 at the immediately preceding impact is greater than the fluctuation amount A1 of the torque current X1 at the previous impact.

[0058] If the fluctuation amount A1 of the torque current X1 at the immediately preceding impact is equal to or less than the fluctuation amount A1 of the torque current X1 at the previous impact (ST2b: No), the movement amount detection unit 3 again detects (ST1) the fluctuation amount A1 of the torque current X1 from when the hammer 22 strikes the anvil 23 to when the next strike is struck. In other words, if the fluctuation amount A1 of the torque current X1 at the immediately preceding impact is equal to or less than the fluctuation amount A1 of the torque current X1 at the previous impact (ST2b: No), the movement amount detection unit 3 detects the fluctuation amount A1 of the torque current X1 at the next strike.

[0059] On the other hand, if the fluctuation amount A1 of the torque current X1 in the immediately preceding impact is greater than the fluctuation amount A1 of the torque current X1 in the previous impact (ST2b: Yes), the movement amount detection unit 3 performs a third judgment step ST2c to further judge whether the fluctuation amount A1 of the torque current X1 has been judged to be greater than the fluctuation amount A1 of the torque current X1 in the previous impact for a predetermined number of consecutive times.

[0060] If the movement amount detection unit 3 has not determined for a predetermined number of consecutive times that the fluctuation amount A1 of the torque current X1 at the immediately preceding impact is larger than the fluctuation amount A1 of the torque current X1 at the previous impact (ST2c: No), the movement amount detection unit 3 again detects the fluctuation amount A1 of the torque current X1 from when the hammer 22 strikes the anvil 23 until the next strike (ST1). In other words, if the movement amount detection unit 3 has not determined for a predetermined number of consecutive times that the fluctuation amount A1 of the torque current X1 is larger than the fluctuation amount A1 of the torque current X1 at the previous impact (ST2c: No), the movement amount detection unit 3 detects the fluctuation amount A1 of the torque current X1 at the next impact.

[0061] On the other hand, if the movement amount detection unit 3 determines a predetermined number of times in succession that the fluctuation amount A1 of the torque current X1 in the immediately preceding impact is greater than the fluctuation amount A1 of the torque current X1 in the previous impact (ST2c: Yes), the movement amount detection unit 3 performs a movement amount detection step ST3 in which the hammer movement amount is detected based on the fluctuation amount A1 of the torque current X1 in the immediately preceding impact. That is, in the movement amount detection step ST3, the movement amount detection unit 3 detects a parameter related to the hammer movement amount by which the hammer 22 moves away from the anvil 23 along the axial direction D1 from the position where the hammer 22 applied the impact to the anvil 23 when the hammer 22 applied the impact to the anvil 23. In the movement amount detection step ST3 of this embodiment, the movement amount detection unit 3 detects the hammer movement amount by which the hammer 22 moves away from the anvil 23 along the axial direction D1 from the position where the hammer 22 applied the impact to the anvil 23 when the hammer 22 applied the impact to the anvil 23. Thereafter, in a rotation speed detection step ST4, the rotation speed detection unit 4 detects the rotation speed of the hammer 22.

[0062] Then, in torque estimation step ST5, torque estimation unit 5 estimates a torque value indicating the magnitude of torque generated in anvil 23 by the immediately preceding impact, based on the hammer movement amount detected by movement amount detection unit 3 in movement amount detection step ST3 and the rotational speed detected by rotational speed detection unit 4 in rotational speed detection step ST4. That is, in torque estimation step ST5, torque estimation unit 5 estimates a torque value indicating the magnitude of torque generated in anvil 23 by the immediately preceding impact, based on at least parameters related to the hammer movement amount.

[0063] After the torque estimation step ST5, the movement amount detection unit 3 again detects the fluctuation amount A1 of the torque current X1 from when the hammer 22 strikes the anvil 23 until the next strike (ST1). In other words, after the torque estimation step ST5, the movement amount detection unit 3 detects the fluctuation amount A1 of the torque current X1 at the next strike. Thereafter, the impact rotary tool 100 does not perform the determination step ST2, but instead performs the movement amount detection step ST3, the rotational speed detection step ST4, and the torque estimation step ST5 to estimate the torque value. That is, after the operator starts the tightening operation, if the movement amount detection unit 3 determines once in the third determination step ST2c that the fluctuation amount A1 of the torque current X1 at the immediately preceding strike is greater than the fluctuation amount A1 of the torque current X1 at the previous strike for a predetermined number of consecutive times, the impact rotary tool 100 does not perform the determination step ST2. The rotary impact tool 100 repeatedly performs the fluctuation amount detection step ST1, the movement amount detection step ST3, the rotational speed detection step ST4, and the torque estimation step ST5 to repeatedly estimate the torque value until the operator finishes the fastening operation.

[0064] (4) Variations The above-described embodiment is merely one of various embodiments of the present disclosure. The above-described embodiment can be modified in various ways depending on the design, etc., as long as the object of the present disclosure can be achieved. Furthermore, functions similar to the movement amount detection unit 3, the rotation speed detection unit 4, the torque estimation unit 5, and the control unit 6 of the rotary impact tool 100 according to the above-described embodiment may be embodied as a computer program, a non-transitory recording medium on which a program is recorded, or the like. A program according to one aspect is a program for causing a computer system to execute the torque estimation method according to the above-described embodiment.

[0065] In the above embodiment, the amount of fluctuation A1 of the torque current X1 from when the hammer 22 strikes the anvil 23 at time T1a until when the hammer 22 strikes the anvil 23 again at time T2a is defined as the difference between the minimum value V1a at time T1a and the maximum value V1b at time T1b. However, the amount of fluctuation A1 of the torque current X1 from when the hammer 22 strikes the anvil 23 at time T1a until when the hammer 22 strikes the anvil 23 again at time T2a may also be defined as the difference between the maximum value V1b at time T1b and the minimum value V2a at time T2a. In other words, the fluctuation amount A1 of the torque current X1 between when the hammer 22 strikes the anvil 23 and when the hammer 22 strikes the anvil 23 again may be defined as the difference between the maximum value when the hammer 22 is moved farthest back and the minimum value when the hammer 22 strikes the anvil 23 again.

[0066] Although the movement amount detection unit 3 in the above-described embodiment detects the hammer movement amount based on the fluctuation amount A1 of the detected torque current X1, it may also be detected by measuring the hammer movement amount. That is, the movement amount detection unit 3 may include a position sensor that measures how far the hammer 22 has moved away from the anvil 23 along the axial direction of the drive shaft 21 from the position where the hammer 22 applied a blow to the anvil 23.

[0067] Furthermore, although the movement amount detection unit 3 in the above-described embodiment detects the hammer movement amount itself as a parameter related to the hammer movement amount, it may also detect the fluctuation amount A1 of the torque current X1 as a parameter related to the hammer movement amount. That is, although the torque estimation unit 5 in the above-described embodiment estimates the torque value based on the hammer movement amount and the rotational speed of the hammer 22, it may also estimate the torque value based on the fluctuation amount A1 of the torque current X1 and the rotational speed of the hammer 22. More specifically, the torque estimation unit 5 may perform machine learning in advance to learn the torque value using both the fluctuation amount A1 of the torque current X1 and the rotational speed of the hammer 22 as feature quantities, and estimate the torque value based on the fluctuation amount A1 of the torque current X1 detected by the movement amount detection unit 3 and the rotational speed detected by the rotational speed detection unit 4. In other words, when estimating the torque value, the torque estimation unit 5 does not need to detect the hammer movement amount from the fluctuation amount A1 of the torque current X1, and may directly estimate the torque value from the fluctuation amount A1 of the torque current X1. That is, the "parameter related to the hammer movement amount" in the present disclosure may be the hammer movement amount itself, or a value that changes according to the hammer movement amount (for example, the fluctuation amount A1 of the torque current X1).

[0068] Furthermore, the movement amount detection unit 3 in the above-described embodiment detects the fluctuation amount A1 of the torque current X1 multiple times during one operation, and detects the hammer movement amount when the fluctuation amount A1 of the torque current X1 shows an increasing trend during the multiple detections. However, the movement amount detection unit 3 may also detect the hammer movement amount after the hammer strikes the anvil a predetermined number of times during one operation. More specifically, the movement amount detection unit 3 may count the number of times the hammer strikes the anvil since the start of the fastening operation, and detect the hammer movement amount when that number reaches a predetermined number. The "predetermined number" here is set empirically, and is set to 10, for example. That is, if the "predetermined number" is set to 10, the movement amount detection unit 3 counts the number of times the hammer strikes the anvil since the start of the fastening operation, and detects the hammer movement amount when that number reaches 10. Note that the "predetermined number" is not limited to 10. According to the above configuration, the movement amount detection unit 3 has the advantage of being able to detect the hammer movement amount more accurately without performing complicated determination processing.

[0069] Although the rotation speed detection unit 4 in the above-described embodiment detects the rotation speed of the hammer 22, it may also detect the rotation speed of the drive shaft 21. That is, the rotation speed detection unit 4 only needs to detect the rotation speed of at least one of the drive shaft 21 and the hammer 22. Furthermore, the torque estimation unit 5 only needs to estimate a torque value indicating the magnitude of torque generated in the anvil 23 due to the impact that the hammer 22 gives to the anvil 23, based on the hammer movement amount and the rotation speed of at least one of the drive shaft 21 and the hammer 22.

[0070] The torque estimation unit 5 in the above-described embodiment estimates a torque value indicating the magnitude of torque generated in the anvil 23 due to the impact of the hammer 22 on the anvil 23, based on the hammer movement amount detected by the movement amount detection unit 3 and the rotational speed detected by the rotational speed detection unit 4. However, the torque estimation unit 5 may estimate a torque value indicating the magnitude of torque generated in the anvil 23 due to the impact of the hammer 22 on the anvil 23, based on the hammer movement amount detected by the movement amount detection unit 3 and the rotational speed of at least one of the drive shaft 21 and the hammer 22 calculated using a setting value R1 (see FIG. 3 ) of the rotational speed of the drive unit 1 that is preset by an operator. That is, the rotational speed of at least one of the drive shaft 21 and the hammer 22 may be detected by the rotational speed detection unit 4 or may be calculated using the setting value R1 of the rotational speed of the drive unit 1. In short, the impact rotary tool 100 does not need to be equipped with a rotational speed detection unit 4, and the torque estimation unit 5 only needs to estimate a torque value indicating the magnitude of the torque generated in the anvil 23 due to the impact that the hammer 22 delivers to the anvil 23, based on at least the hammer movement amount detected by the movement amount detection unit 3.

[0071] (summary) A rotary impact tool (100) according to a first aspect of the embodiment includes a drive unit (1), a drive shaft (21), a hammer (22), an anvil (23), a movement amount detection unit (3), and a torque estimation unit. The drive unit (1) rotates. The drive shaft (21) is rotated by the drive unit (1). The hammer (22) is fitted to the outer periphery of the drive shaft (21) so as to be movable in the axial direction (D1) of the drive shaft (21) and rotatable in the rotational direction of the drive shaft (21). The anvil (23) is struck by the hammer (22) in the rotational direction. The movement amount detection unit (3) detects a parameter related to the hammer movement amount, which is the amount by which the hammer (22) moves away from the anvil (23) along the axial direction (D1) from the position where the hammer (22) struck the anvil (23). The torque estimation unit estimates a torque value generated by the impact based on at least a parameter related to the hammer movement amount.

[0072] This embodiment has the advantage that the torque value can be accurately estimated.

[0073] The rotary impact tool 100 of the second aspect according to the embodiment is the same as that of the first aspect, and further includes a rotational speed detection unit 4. The rotational speed detection unit 4 detects the rotational speed of at least one of the drive shaft 21 and the hammer 22. The torque estimation unit estimates a torque value based on a parameter related to the hammer movement amount and the rotational speed.

[0074] This embodiment has the advantage that the torque value can be estimated more accurately by taking into account fluctuations in the rotational speed of at least one of the drive shaft (21) and the hammer (22).

[0075] The rotary impact tool 100 of a third aspect according to the present embodiment is the first or second aspect, and further includes a control unit 6 that performs vector control of the drive unit 1. A torque current X1 is supplied to the drive unit 1 through vector control by the control unit 6. The movement amount detection unit 3 detects a fluctuation amount A1 of the torque current X1 from when the hammer 22 strikes the anvil 23 until the next strike, and detects the hammer movement amount itself based on the fluctuation amount A1 as a parameter related to the hammer movement amount.

[0076] According to this aspect, there is an advantage that it is not necessary to provide a new sensor for detecting the amount of movement of the hammer, and the torque value can be accurately estimated.

[0077] In the impact rotary tool (100) of the fourth aspect according to the embodiment, in the third aspect, the movement amount detection unit (3) detects the fluctuation amount (A1) multiple times during one operation. The movement amount detection unit (3) detects the hammer movement amount when the fluctuation amount (A1) shows an increasing tendency in the multiple detections.

[0078] This embodiment has the advantage that the amount of movement of the hammer can be detected more accurately based on the amount of fluctuation (A1) of the torque current (X1).

[0079] In the impact rotary tool (100) of the fifth aspect of the embodiment, in the fourth aspect, the movement amount detection unit (3) determines that the fluctuation amount (A1) shows an increasing tendency when the fluctuation amount (A1) increases a predetermined number of times consecutively in multiple detections.

[0080] This aspect has the advantage that the amount of hammer movement can be detected more accurately regardless of the material of the fastening part or fastening member.

[0081] In the sixth aspect of the impact rotary tool (100) according to the third aspect, the movement amount detection unit (3) detects the movement amount of the hammer after the hammer (22) strikes the anvil (23) a predetermined number of times during one operation.

[0082] According to this aspect, there is an advantage that the movement amount detection unit (3) can detect the movement amount of the hammer more accurately without performing complicated determination processing.

[0083] A torque estimation method according to a seventh aspect of the embodiment is a torque estimation method for estimating a torque value generated by an impact of a rotary impact tool including a drive unit (1), a drive shaft (21), a hammer (22), and an anvil (23). The drive unit (1) rotates. The drive shaft (21) is rotated by the drive unit (1). The hammer (22) is fitted to the outer periphery of the drive shaft (21) so as to be movable in the axial direction (D1) of the drive shaft (21) and rotatable in the rotational direction of the drive shaft (21). The anvil (23) is struck in the rotational direction by the hammer (22). The torque estimation method includes a movement amount detection step (ST3) and a torque estimation step (ST5). In the movement amount detection step (ST3), a parameter related to the hammer movement amount, which is the amount by which the hammer (22) moves away from the anvil (23) along the axial direction (D1) from the position where the hammer (22) applied a blow to the anvil (23), is detected. In the torque estimation step (ST5), a torque value generated by the blow is estimated based on at least the parameter related to the hammer movement amount.

[0084] This embodiment has the advantage that the torque value can be accurately estimated without using a dedicated rotary impact tool (100).

[0085] A program according to an eighth aspect of the embodiment is a program for causing a computer system to execute the torque estimation method according to the seventh aspect.

[0086] This embodiment has the advantage that the torque value can be accurately estimated. [Explanation of symbols]

[0087] 100 Impact rotary tools 1 Drive unit 21 Drive shaft 22 Hammer 23 Anvil 3. Movement detection section 4 Rotational speed detection section 5 Torque estimation section 6 Control Unit A1 Variation D1 Axial direction ST3 Movement detection step ST5 Torque estimation step X1 torque current

Claims

1. a drive unit that performs a rotational movement; a drive shaft rotated by the drive unit; a hammer fitted to the outer periphery of the drive shaft so as to be movable in the axial direction of the drive shaft and rotatable in the rotation direction of the drive shaft; an anvil to which the hammer applies a strike in the rotational direction; a movement amount detection unit that detects a parameter related to a hammer movement amount, which is a movement amount of the hammer that moves away from the anvil along the axial direction from a position where the hammer applied the blow to the anvil when the hammer applied the blow to the anvil; a torque estimation unit that estimates a torque value generated by the impact based on at least the parameters; a control unit that performs vector control of the drive unit, a torque current is supplied to the drive unit by vector control of the control unit; The movement amount detection unit detecting a variation in the torque current from one impact by the hammer to the anvil until the next impact; As the parameter, the hammer movement amount itself is detected based on the fluctuation amount. A rotary impact tool characterized by:

2. a rotational speed detection unit that detects the rotational speed of at least one of the drive shaft and the hammer; the torque estimation unit estimates the torque value based on the parameter and the rotation speed. The rotary impact tool according to claim 1 .

3. The movement amount detection unit Detecting the amount of fluctuation multiple times during one operation, When the fluctuation amount shows an increasing tendency in the multiple detections, the hammer movement amount is detected.

3. The rotary impact tool according to claim 1 or 2.

4. The movement amount detection unit determines that the amount of fluctuation shows an increasing trend when the amount of fluctuation increases a predetermined number of times consecutively during the multiple detections. The rotary impact tool according to claim 3 .

5. The movement amount detection unit detects the movement amount of the hammer after the hammer has struck the anvil a predetermined number of times during one operation.

3. The rotary impact tool according to claim 1 or 2.

6. A drive unit that performs a rotational movement; a drive shaft rotated by the drive unit; a hammer fitted to the outer periphery of the drive shaft so as to be movable in the axial direction of the drive shaft and rotatable in the rotation direction of the drive shaft; an anvil to which the hammer applies an impact in the rotational direction, the anvil comprising: a rotary impact tool; and a torque estimation method for estimating a torque value generated by the impact, the torque estimation method comprising: a movement amount detection step of detecting a parameter related to a hammer movement amount by which the hammer moves away from the position where the hammer applied the blow to the anvil along the axial direction when the hammer applied the blow to the anvil; a torque estimation step of estimating a torque value generated by the impact based on at least the parameters; a control step of vector-controlling the drive unit, a torque current is supplied to the drive unit by vector control in the control step; In the movement amount detection step, detecting a variation in the torque current from one impact by the hammer to the anvil until the next impact; The hammer movement amount itself is detected based on the fluctuation amount as the parameter. A torque estimation method comprising:

7. A computer system comprising: A program for executing the torque estimation method according to claim 6.

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