Impact rotary tool, torque estimation method, and non-transitory recording medium

Abstract

The object of the present invention is to provide an impact rotary tool configured to accurately estimate torque values, a torque estimation method, and a non-transient recording medium. The impact rotary tool (100) includes a driver (1), a drive shaft (21), a hammer (22), an anvil (23), a travel distance measuring device (3), and a torque estimation unit (5). The travel distance measuring device (3) is configured to measure parameters related to the hammer travel distance, wherein when the hammer (22) impacts the anvil (23), the hammer (22) moves away from the anvil (23) along an axial direction (D1) by the hammer travel distance from the position where the hammer (22) impacts the anvil (23). The torque estimation unit (5) is configured to estimate the torque value generated by the impact, at least based on parameters related to the hammer travel distance.

Description

Technical Field

[0001] This invention generally relates to impact-rotation tools, torque estimation methods, and non-transient recording media. Specifically, this invention relates to impact-rotation tools configured to estimate torque values, torque estimation methods, and non-transient recording media. Background Technology

[0002] Patent document 1 (JP 2005-324265 A) discloses an impact rotary tool, which includes a rotary drive mechanism, an output shaft, a processor, a rotation speed setting unit, and a controller. The rotary drive mechanism rotates a hammer via the drive shaft. A driving force is applied to the output shaft by the impact of the hammer. The processor calculates a tightening torque based on the impact of the hammer. The rotation speed setting unit changes the rotation speed of the rotary drive mechanism. The controller causes the rotary drive mechanism to rotate at a speed set in the rotation speed setting unit, and stops the rotary drive mechanism when the tightening torque calculated in the processor becomes greater than or equal to a preset tightening torque value in the torque setting unit. Summary of the Invention

[0003] The problem the invention aims to solve

[0004] As described above, the impact rotary tool calculates the tightening torque value (torque value) based on the rotational speed of the rotary drive mechanism and the number of hammer impacts. However, even with the same number of hammer impacts and the same rotational speed, the tightening torque value may vary depending on the type of fastening component (e.g., screw, bolt, nut). Therefore, an impact rotary tool needs to be configured to accurately estimate the tightening torque value.

[0005] The purpose of this invention is to provide an impact rotation tool configured to accurately estimate torque values, a torque estimation method, and a non-transient recording medium.

[0006] Solution for solving the problem

[0007] An impact rotary tool according to one aspect of the invention includes a driver, a drive shaft, a hammer, an anvil, a travel distance measuring device, and a torque estimation unit. The driver is configured to perform a rotational operation. The drive shaft is configured to rotate by the driver. The hammer is configured to be mounted to the outer periphery of the drive shaft such that the hammer is movable in the axial direction of the drive shaft and rotatable in the rotational direction of the drive shaft. The anvil is configured to receive an impact applied by the hammer in the rotational direction. The travel distance measuring device is configured to measure parameters related to the hammer's travel distance, wherein when the hammer impacts the anvil, the hammer travels the distance from the anvil along the axial direction from the position where the hammer impacts the anvil. The torque estimation unit is configured to estimate the torque value generated by the impact based at least on the parameters.

[0008] According to one aspect of the invention, a torque estimation method is used to estimate the torque value generated by an impact applied by an impact rotating tool, the impact rotating tool including a driver, a drive shaft, a hammer, and an anvil. The driver is configured to perform a rotational operation. The drive shaft is configured to rotate by the driver. The hammer is configured to be mounted to the outer periphery of the drive shaft such that the hammer is movable in the axial direction of the drive shaft and rotatable in the rotational direction of rotation of the drive shaft. The anvil is configured to receive an impact applied by the hammer in the rotational direction. The torque estimation method includes a travel distance measurement step and a torque estimation step. The travel distance measurement step includes measuring a parameter related to the hammer travel distance, wherein when the hammer impacts the anvil, the hammer travels a distance away from the anvil along the axial direction from the position where the hammer impacts the anvil. The torque estimation step includes estimating the torque value generated by the impact based at least on the parameter.

[0009] According to one aspect of the invention, a non-transient recording medium is a non-transient recording medium for recording a program configured to cause a computer system to execute the torque estimation method.

[0010] The effects of the invention

[0011] This invention provides the advantage of being able to accurately estimate torque values. Attached Figure Description

[0012] Figure 1 This is a block diagram illustrating the structure of the impact rotation tool in this embodiment;

[0013] Figure 2 This is a structural diagram illustrating the impact rotation tool;

[0014] Figure 3 This is an explanatory diagram showing the change of torque current over time in the impact rotary tool, as well as the calculated and target values ​​of the drive's rotational speed over time; and

[0015] Figure 4 This is a flowchart of the torque estimation method.

[0016] List of reference numerals

[0017] 100 Impact Rotary Tool

[0018] 1 drive

[0019] 21 drive shafts

[0020] 22 hammers

[0021] 23 Anvil

[0022] 3. Travel distance measuring device

[0023] 4. Rotational speed measuring device

[0024] 5 Torque Estimation Unit

[0025] 6 controllers

[0026] A1 Change

[0027] D1 Axial direction

[0028] ST3 Distance Measurement Procedure

[0029] ST5 Torque Estimation Steps

[0030] X1 Torque Current Detailed Implementation

[0031] (Example)

[0032] (1) Overview

[0033] The following will be referenced Figure 1 and Figure 2 This section provides an overview of the impact rotation tool according to this embodiment.

[0034] like Figure 1 and Figure 2 As shown, the impact rotary tool 100 according to this embodiment includes a driver 1, a drive shaft 21, a hammer 22, an anvil 23, a travel distance measuring device 3, and a torque estimation unit 5. For example, suppose an operator uses the impact rotary tool 100 in a fastening operation to fasten fastening components (such as screws, bolts, or nuts) to fastening targets (such as electronic products or furniture).

[0035] The driver 1 performs a rotational operation. The drive shaft 21 is rotated by the driver 1. The hammer 22 is mounted on the outer periphery of the drive shaft 21, such that the hammer 22 can move in the axial direction of the drive shaft 21 and can rotate in the rotational direction of the drive shaft 21. The anvil 23 receives the impact exerted by the hammer 22 in the rotational direction of the drive shaft 21.

[0036] The travel distance measuring device 3 measures parameters related to the hammer travel distance (the magnitude of the movement of the hammer 22). The hammer travel distance is the distance traveled by the hammer 22 along the axial direction D1 of the drive shaft 21 from the position where the hammer 22 impacts the anvil 23 (see [reference]). Figure 2 The distance traveled is moved away from the anvil 23. The torque estimation unit 5 is configured to estimate the torque value generated by the impact based at least on the parameters measured by the travel distance measuring device 3. As used herein, "torque value" refers to the magnitude of the torque generated by the impact, that is, the magnitude of the torque applied to the fastening member.

[0037] Typically, even when the number of impacts applied by the hammer 22 is the same and the rotation speed is the same, differences in the type of fastening member (such as a metal screw or a wood screw) will cause the anvil 23 to advance differently in the rotational direction due to the impacts applied by the hammer 22, and the torque value generated by the impacts may also differ. Therefore, when estimating the torque value based on the number of impacts applied by the hammer 22 or the rotation speed, the differences in torque values ​​depending on the type of fastening member cannot be taken into account, making it difficult to accurately estimate the torque value.

[0038] However, in the impact-rotating tool 100 of this embodiment, the torque estimation unit 5 estimates the torque value generated by the impact based at least on the hammer travel distance. When the hammer 22 impacts the anvil 23, the hammer 22 moves away from the anvil 23 due to the repulsive force of the anvil 23 resisting the impact. The repulsive force of the anvil 23 resisting the impact changes according to the progress in the rotation direction of the anvil 23, and therefore the hammer travel distance changes according to the progress in the rotation direction of the anvil 23. Therefore, the impact-rotating tool 100 of this embodiment makes it possible to estimate the torque value based on the type of fastening member and taking into account the difference in the progress in the rotation direction of the anvil 23. In other words, the impact-rotating tool 100 of this embodiment has the advantage of being able to accurately estimate the torque value.

[0039] (2) Detailed Structure

[0040] (2-1) Overall Structure

[0041] The following will be referenced Figures 1 to 3 The detailed structure of this embodiment will be explained below.

[0042] like Figure 1 and Figure 2 As shown, the impact rotary tool 100 includes, in addition to the driver 1, the travel distance measuring device 3 and the torque estimation unit 5, an impact mechanism 2, a rotation speed measuring device 4, a controller 6, a reduction mechanism 91, an output shaft 92 and a holding part 93.

[0043] In the following description, the axial direction D1 of the drive shaft 21 described later (see [reference]) will be used. Figure 2 The direction is defined as front / back. It is assumed that the anvil 23 described later is in front of the hammer 22 described later, and that the hammer 22 is behind the anvil 23.

[0044] The impact rotary tool 100 preferably includes a computer system. The computer system includes a processor and memory as its main hardware components. The processor executes programs stored in the computer system's memory to achieve at least some of the functions of the travel distance measuring device 3, the rotation speed measuring device 4, the torque estimation unit 5, and the controller 6 of the present invention. The computer system includes a processor that operates according to a program as its main hardware component. Any type of processor can be used, as long as it can achieve (one or more) functions by executing a program. The processor includes one or more electronic circuits comprising a semiconductor integrated circuit (IC) or a large-scale integrated circuit (LSI). As used herein, "integrated circuit," such as IC or LSI, is referred to by different names depending on its degree of integration. Examples of integrated circuits include system LSIs, very large-scale integrated circuits (VLSIs), and ultra-large-scale integrated circuits (ULSIs). Alternatively, a field-programmable gate array (FPGA) that is programmed after the LSI is manufactured, or a reconfigurable logic device that allows reconfiguration of connections or circuit sections within the LSI, can also be used as the processor. These electronic circuits can be integrated together on a single chip or distributed across multiple chips, either way being suitable. These multiple chips can be integrated together in a single device or distributed across multiple devices without limitation.

[0045] (2-2) Driver

[0046] Driver 1 performs a rotational operation. More specifically, driver 1 uses power source B1 (see [link to power supply]). Figure 2 The power source B1 is supplied with electricity to operate, thereby performing the rotational operation. As an example, the power source B1 is a rechargeable battery pack detachably attached to the impact rotary tool 100. The power source B1 is not a constituent element of the impact rotary tool 100. However, the impact rotary tool 100 may include the power source B1 as a constituent element.

[0047] The driver 1 is, for example, a brushless motor. In particular, the driver 1 in this embodiment is a synchronous motor, and specifically a permanent magnet synchronous motor (PMSM). The driver 1 includes: a rotor, which includes a rotating shaft and permanent magnets; and a stator, which includes three-phase (U-phase, V-phase and W-phase) armature windings.

[0048] The torque and rotational speed of the driver 1 are changed according to the control of the controller 6. The controller 6 controls the motor current flowing to the driver 1 by using the power supplied from the power source B1, thereby controlling the torque and rotational speed of the driver 1. In this embodiment, the controller 6 controls the driver 1 according to vector control. More specifically, the controller 6 in this embodiment performs vector control by decomposing the motor current into a torque current for generating torque and an excitation current for generating magnetic flux, and controlling these current components separately. That is, the driver 1 is supplied with torque current and excitation current according to the vector control performed by the controller 6.

[0049] (2-3) Impact Mechanism

[0050] The impact rotary tool 100 of this embodiment performs a fastening operation while simultaneously causing the impact mechanism 2 to perform an impact operation. The impact mechanism 2 generates an impact force through the impact operation based on the power of the driver 1, and applies this impact force to the front-end tool C1 (see...). Figure 2 ).

[0051] like Figure 2 As shown, the impact mechanism 2 includes a drive shaft 21, a hammer 22, an anvil 23, and an elastic member 24.

[0052] like Figure 2 As shown, drive shaft 21 is mechanically connected to the rotating shaft of driver 1 via reduction mechanism 91. Reduction mechanism 91 converts the rotational speed and torque of the rotating shaft of driver 1 into the rotational speed and torque required for operating the rotating screw. The torque of the rotating shaft of driver 1 is transmitted to drive shaft 21 via reduction mechanism 91. As a result, drive shaft 21 rotates. Drive shaft 21 is the so-called spindle.

[0053] Hammer 22 is mounted on the outer periphery of drive shaft 21, so that hammer 22 can move in the axial direction D1 of drive shaft 21 and rotate in the rotational direction of drive shaft 21. The rotational force of drive shaft 21 is transmitted to hammer 22, and thus hammer 22, together with drive shaft 21, rotates in the rotational direction of drive shaft 21.

[0054] An elastic member 24 is arranged between the reduction mechanism 91 and the hammer 22. The hammer 22 receives a force from 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 toward the anvil by the elastic member 24 along the axial direction D1 of the drive shaft 21. The elastic member 24 in this embodiment is, for example, a conical helical spring.

[0055] The anvil 23 includes a joint that engages with the hammer 22 in the direction of rotation. When the hammer 22 and the anvil 23 are engaged, the rotational force of the hammer 22 is transmitted to the anvil 23. This causes the anvil 23 to rotate.

[0056] In this embodiment, the output shaft 92 is integrally formed with the anvil 23. A retaining portion 93 is provided at the front end of the output shaft 92. The output shaft 92 transmits the rotational power of the anvil 23 to the retaining portion 93.

[0057] The retaining part 93 holds the front-end tool C1. More specifically, the front-end tool C1 is detachably attached to the retaining part 93. Alternatively, the retaining part 93 and the front-end tool C1 can be integrally formed as a single part. In this embodiment, the output shaft 92 and the front-end tool C1 rotate together with the anvil 23.

[0058] The front-end tool C1 is, for example, a screwdriver or drill bit. The front-end tool C1 is mounted to a fastening component. The front-end tool C1, mounted to the fastening component, rotates, thereby enabling machining operations such as tightening the fastening component. In this embodiment, the front-end tool C1 is not included in the assembly of the impact rotary tool 100. However, the front-end tool C1 may be included in the assembly of the impact rotary tool 100.

[0059] The impact mechanism 2 performs an impact operation when an impact condition related to the magnitude of the rotational force applied from the hammer 22 to the anvil 23 is met. The impact operation is the application of an impact force from the hammer 22 to the anvil 23. In this embodiment, the impact condition is that the rotational force of the hammer 22 is greater than or equal to a predetermined value. As the rotational force of the hammer 22 increases, the proportion of the backward component of the hammer 22 relative to the force generated between the hammer 22 and the anvil 23 increases. When the rotational force of the hammer 22 becomes greater than or equal to the predetermined value, the hammer 22 retracts while compressing the elastic member 24. Then, upon receiving a restoring force from the elastic member 24, the hammer 22 advances while rotating. The drive shaft 21 then rotates by a predetermined amount (e.g., approximately half a turn), causing the hammer 22 to collide with the anvil 23. That is, whenever the drive shaft 21 rotates by a predetermined amount, the anvil 23 receives an impact in the rotational direction from the hammer 22. As mentioned in this invention, "backward" means moving backward in the forward / backward direction, and "forward" means moving forward in the forward / backward direction.

[0060] As described above, in the impact mechanism 2, the hammer 22 repeatedly impacts the anvil 23 in the rotational direction. Compared to the case without impact, the torque generated by the impact makes it possible to securely fasten the fastening member.

[0061] (2-4) Travel distance measuring device

[0062] In this embodiment, the travel distance measuring device 3 measures the hammer travel distance itself as a parameter related to the hammer travel distance. That is, the travel distance measuring device 3 measures the hammer travel distance, wherein when the hammer 22 impacts the anvil 23, the hammer 22 moves away from the anvil 23 along the axial direction D1 from the position where the hammer 22 impacts the anvil 23, covering the distance traveled. More specifically, the hammer travel distance represents the distance the hammer 22 retracts along the axial direction D1 from the position where the hammer 22 impacts the anvil 23.

[0063] To explain how the travel distance measuring device 3 of this embodiment measures the travel distance of the hammer, the change A1 of the torque current X1 supplied to the driver 1 according to the vector control performed by the controller 6 will be explained first. Figure 3 The diagram shows the variation of torque current X1 over time during the period when the impact rotating tool 100 performs a fastening operation while the impact mechanism 2 is in the impact phase. Torque current X1 is supplied to the driver 1 according to vector control performed by the controller 6.

[0064] Typically, the torque current X1 varies depending on the magnitude of the load applied to driver 1. That is, as the load applied to driver 1 increases, the torque current X1 increases, and as the load applied to driver 1 decreases, the torque current X1 decreases. Therefore, as... Figure 3 As shown, whenever the hammer 22 impacts the anvil 23, the torque current X1 repeats the following changes: the torque current X1 begins to increase from the point when the hammer 22 impacts the anvil 23, and the torque current X1 begins to decrease immediately after the maximum retreat of the hammer 22.

[0065] More specifically, see reference Figure 3 The change in torque current X1 caused by the hammer 22 impacting the anvil 23 at time T1a and then at time T2a is illustrated as an example. Figure 3 In the middle, time T1b corresponds to the timing of the maximum backward movement of hammer 22.

[0066] Before hammer 22 impacts anvil 23 at time T1a, hammer 22 is rotating in a state where it is detached from anvil 23. Since hammer 22 is not engaged with anvil 23, the load applied to driver 1 is low, and the torque current X1 is consequently low. Then, at time T1a, hammer 22 impacts anvil 23, and thus hammer 22 detaches from anvil 23. During the time interval from time T1a to time T1b, hammer 22 retracts while compressing elastic member 24. While hammer 22 is retracting, driver 1 supplies energy to hammer 22, thus increasing the load applied to driver 1, and consequently increasing the torque current X1. During the time interval from time T1b to time T2a, hammer 22, detached from anvil 23, advances while rotating. While hammer 22 is advancing, driver 1 does not supply energy to hammer 22, thus decreasing the load applied to driver 1, and consequently decreasing the torque current X1. Afterwards, at time T2a, the hammer 22 impacts the anvil 23 again, and while compressing the elastic member 24, the hammer 22 retracts. During this retraction, the driver 1 supplies energy to the hammer 22, thus increasing the load on the driver 1 and consequently increasing the torque current X1. Therefore, the torque current X1 at time T1a when the hammer 22 impacts the anvil 23 is a local minimum V1a, and the torque current X1 corresponding to the maximum retraction of the hammer 22 at time T1b is a local maximum V1b. Furthermore, the torque current X1 at time T2a when the hammer 22 impacts the anvil 23 is a local minimum V2a. During the time period when the impact rotating tool 100 performs a fastening operation during the impact operation of the impact mechanism 2, the torque current X1 repeats the above-described changes whenever the hammer 22 impacts the anvil 23.

[0067] In this embodiment, the change A1 of torque current X1 during the time period from the time T1a when hammer 22 impacts anvil 23 until the time T2a when hammer 22 impacts anvil 23 again is defined as the difference between the local minimum V1a at time T1a and the local maximum V1b at time T1b. In other words, in this embodiment, the change A1 of torque current X1 during the time period from the time hammer 22 impacts anvil 23 until the time hammer 22 impacts anvil 23 again is defined as the difference between the local minimum when hammer 22 impacts anvil 23 and the local maximum when hammer 22 retreats to its maximum extent.

[0068] During the period when hammer 22 retracts while compressing elastic member 24, actuator 1 continues to apply force to hammer 22. As the distance traveled by hammer 22 due to the impact of hammer 22 on anvil 23 increases, the load applied to actuator 1 increases. That is, as the distance traveled by hammer 22 due to the impact of hammer 22 on anvil 23 increases, the change in torque current X1 A1 increases. In other words, the change in torque current X1 A1 changes according to the distance traveled by hammer 22 due to the impact of hammer 22 on anvil 23 at time T1a. In other words, the change in torque current X1 A1 is related to the distance traveled by hammer 22 due to the impact of hammer 22 on anvil 23 at time T1a.

[0069] Therefore, the travel distance measuring device 3 of this embodiment measures the change A1 of torque current X1 during the time period from when the hammer 22 impacts the anvil 23 until the next time the hammer 22 impacts the anvil 23. Based on the measured change A1 of torque current X1, the travel distance measuring device 3 measures the hammer travel distance itself as a parameter related to the hammer travel distance. More specifically, the travel distance measuring device 3 of this embodiment measures the change A1 of torque current X1 during the time period from when the hammer 22 impacts the anvil 23 until the next time the hammer 22 impacts the anvil 23. Based on the measured change A1 of torque current X1, the travel distance measuring device 3 measures the hammer travel distance caused by the impact of the hammer 22 on the anvil 23 at time T1a.

[0070] Specifically, the travel distance measuring device 3 in this embodiment includes a current sensor configured to detect the torque current supplied to the driver 1 according to vector control performed by the controller 6. In this embodiment, the current sensor of the travel distance measuring device 3 is integrated with a current sensor for vector control. This configuration has the advantage that the impact rotary tool 100 can estimate the torque value with improved accuracy without the need for an additional sensor for sensing the hammer's travel distance.

[0071] In this embodiment, the travel distance measuring device 3 measures the change in torque current X1 A1 multiple times during a machining operation. When the change in torque current X1 A1 shows an increasing trend during these multiple measurements, the travel distance measuring device 3 measures the hammer travel distance. More specifically, in a fastening operation, the travel distance measuring device 3 measures the change in torque current X1 A1 each time the hammer 22 impacts the anvil 23. When the change in torque current X1 A1 shows an increasing trend, the travel distance measuring device 3 measures the hammer travel distance. Typically, at the point when the user begins the fastening operation using the impact rotating tool 100, the fastening member is not yet fastened. Therefore, the anvil 23 rotates along with the fastening member, and thus, the rotation angle of the fastening member increases each time the hammer 22 impacts the anvil 23. Therefore, at the start of the fastening operation, the hammer travel distance is short, but there may still be a situation where the change in torque current X1 A1 increases. Once the change in torque current X1, A1, increases, it tends to decrease until the fastening member is tightened to a certain extent. However, time has elapsed since the user began the tightening operation using the impact rotating tool 100, thus the fastening member has been tightened to a certain extent. Consequently, whenever the hammer 22 impacts the anvil 23, the rotation angle of the fastening member decreases, which increases the repulsive force of the anvil 23 on the impact, thereby increasing the hammer's travel distance. Therefore, the change in torque current X1, A1, for each impact tends to increase. This configuration allows the hammer's travel distance to be measured based on the change in torque current X1, A1, at the point in time when the rotation angle of the fastening member decreases each time an impact is applied. In other words, this configuration has the advantage of measuring the hammer's travel distance with further improved accuracy based on the change in torque current X1, A1.

[0072] When the change in torque current X1 A1 increases continuously for a predetermined number of times in multiple measurements, the travel distance measuring device 3 of this embodiment determines that the change in A1 shows an increasing trend. More specifically, the travel distance measuring device 3 of this embodiment stores historical information related to the change in torque current X1 A1 measured each time the hammer 22 impacts the anvil 23, and when the travel distance measuring device 3 determines that the change in torque current X1 A1 is greater than the change in torque current X1 A1 caused by the previous impact for a predetermined number of consecutive times, the travel distance measuring device 3 determines that the change in A1 shows an increasing trend. As used herein, the "predetermined number of times" is set based on experience, and is, for example, three times. That is, when the "predetermined number of times" is set to three times, when the change in torque current X1 A1 measured in three consecutive impacts increases continuously, the travel distance measuring device 3 of this embodiment determines that the change in A1 shows an increasing trend. Note that the "predetermined number of times" in this invention is not limited to this example. This configuration has the advantage that the hammer travel distance is measured with improved accuracy regardless of the fastening member or the material of the fastening member.

[0073] (2-5) Rotation speed measuring device

[0074] The rotational speed measuring device 4 measures the rotational speed of the hammer 22. In this embodiment, the rotational speed measuring device 4 measures the rotational speed of the hammer 22 based on the number of revolutions of the driver 1. The rotational speed measuring device 4 detects the excitation current supplied to the driver 1 by the controller 6 and calculates the number of revolutions of the driver 1 based on the detected excitation current. That is, the rotational speed measuring device 4 includes a current sensor configured to detect the excitation current supplied to the driver 1 by the controller 6.

[0075] Figure 3 The diagram shows the changes over time of the calculated value X2 and the target value X3 of the drive 1's rotational speed during the period when the impact mechanism 2 performs the fastening operation while the impact rotary tool 100 is in operation. The calculated value X2 is obtained from the rotational speed measuring device 4. The drive 1 is controlled by vector control performed by the controller 6. Figure 3 The setting value R1 shown is a rotational speed value preset by the operator, making it suitable for fastening operations performed by the impact rotary tool 100. The controller 6 calculates the target value X3, causing the drive 1 to reach the setting value R1.

[0076] like Figure 3As shown, the calculated value X2 of the rotational speed of the driver 1 changes whenever the hammer 22 impacts the anvil 23. Therefore, the rotational speed measuring device 4 of this embodiment measures the rotational speed of the hammer 22 based on the calculated value X2 of the rotational speed of the driver 1, thereby measuring the changing rotational speed of the hammer 22 whenever the hammer 22 impacts the anvil 23 with improved accuracy.

[0077] (2-6) Torque estimation unit

[0078] The distance the hammer travels when it impacts the anvil 23 depends on the physical parameters of the impact mechanism 2, the rotational speed of the hammer 22, and the torque generated at the anvil 23 by the impact. As used herein, the "physical parameters of the impact mechanism 2" refers to the materials or dimensions of the drive shaft 21, hammer 22, anvil 23, and elastic member 24 included in the impact mechanism 2. That is, the "physical parameters of the impact mechanism 2" do not change depending on the fastening target or fastening member, but are uniquely determined for each impact rotating tool 100.

[0079] Therefore, the torque estimation unit 5 estimates a torque value representing the magnitude of the torque generated at the anvil 23 by the impact applied by the hammer 22 to the anvil 23 based on parameters related to the hammer travel distance measured by the travel distance measuring device 3, the rotational speed measured by the rotational speed measuring device 4, and the physical parameters of the impact mechanism 2. In this embodiment, the torque estimation unit 5 estimates a torque value representing the magnitude of the torque generated at the anvil 23 by the impact applied by the hammer 22 to the anvil 23 based on the hammer travel distance measured by the travel distance measuring device 3, the rotational speed measured by the rotational speed measuring device 4, and the physical parameters of the impact mechanism 2. More specifically, a learned model is generated by performing machine learning on the torque value in advance, where both the hammer travel distance and the rotational speed of the hammer 22 are feature quantities, and the torque estimation unit 5 in this embodiment estimates the torque value based on the hammer travel distance measured by the travel distance measuring device 3 and the rotational speed measured by the rotational speed measuring device 4 according to the learned model.

[0080] (3) Operation

[0081] Next, refer to Figure 4 To illustrate the torque estimation method, which is used to estimate a torque value representing the magnitude of the torque generated by the impact applied by the impact rotating tool 100.

[0082] like Figure 4 As shown, the torque estimation method includes step ST1 for measuring the change, step ST2 for judging, step ST3 for measuring the travel distance, step ST4 for measuring the rotational speed, and step ST5 for estimating the torque.

[0083] The operator begins the tightening operation using the impact rotating tool 100. Then, in the change measurement step ST1, the travel distance measuring device 3 measures the change A1 of the torque current X1 during the time period from when the hammer 22 impacts the anvil 23 until the next time the hammer 22 impacts the anvil 23. More specifically, the travel distance measuring device 3 measures the change A1 of the torque current X1 during the time period from when the hammer 22 impacts the anvil 23 until the next time the hammer 22 impacts the anvil 23, and stores the change A1 of the torque current X1 as historical information.

[0084] Then, in the judgment step ST2, the travel distance measuring device 3 determines whether the change A1 of the torque current X1 in multiple measurements shows an increasing trend. In the judgment step ST2 of this embodiment, the travel distance measuring device 3 determines whether the change A1 of the torque current X1 in multiple measurements increases continuously for a predetermined number of times. The judgment step ST2 of this embodiment includes a first judgment step ST2a, a second judgment step ST2b, and a third judgment step ST2c.

[0085] In the first judgment step ST2a, the travel distance measuring device 3 determines whether both the change A1 of torque current X1 in the immediate preceding impact and the change A1 of torque current X1 in the previous impact should be stored as historical information. As used herein, "immediate preceding impact" is the impact in which the change A1 of torque current X1 was measured in the change measurement step ST1 performed before the currently executed judgment step ST2. Furthermore, as used herein, "previous impact" is one of the multiple impacts repeatedly applied to the anvil 23 that occurred before the "immediate preceding impact".

[0086] In the case where only the change A1 of torque current X1 in the immediate preceding impact is stored and the change A1 of torque current X1 in the previous impact is not stored ("No" in ST2a), the travel distance measuring device 3 again measures the change A1 of torque current X1 in the time period from when hammer 22 impacts anvil 23 until the next time hammer 22 impacts anvil 23 (ST1). In other words, in the case where only the change A1 of torque current X1 in the immediate preceding impact is stored and the change A1 of torque current X1 in the previous impact is not stored ("No" in ST2a), the travel distance measuring device 3 measures the change A1 of torque current X1 in the next impact. As used herein, "in the case where only the change A1 of torque current X1 in the immediate preceding impact is stored and the change A1 of torque current X1 in the previous impact is not stored" assumes the following situation: the operator starts the tightening operation, then measures the change A1 of torque current X1 in the initial impact in the change measurement step ST1, and proceeds to the first judgment step ST2a.

[0087] In contrast, when storing both the change A1 of torque current X1 in the immediate preceding impact and the change A1 of torque current X1 in the previous impact ("yes" in ST2a), the travel distance measuring device 3 executes a second judgment step ST2b, which is used to determine whether the change A1 of torque current X1 in the immediate preceding impact is greater than the change A1 of torque current X1 in the previous impact.

[0088] If the change in torque current X1 A1 in the immediate preceding impact is less than or equal to the change in torque current X1 A1 in the previous impact (No in ST2b), the travel distance measuring device 3 again measures the change in torque current X1 A1 (ST1) during the time period from when the hammer 22 impacts the anvil 23 until the hammer 22 impacts the anvil 23 again. In other words, if the change in torque current X1 A1 in the immediate preceding impact is less than or equal to the change in torque current X1 A1 in the previous impact (No in ST2b), the travel distance measuring device 3 measures the change in torque current X1 A1 in the next impact.

[0089] In contrast, if the change in torque current X1 in the immediate impact is greater than the change in torque current X1 in the previous impact ("yes" in ST2b), the travel distance measuring device 3 executes a third judgment step ST2c, which is used to further determine whether the change in torque current X1 in the immediate impact is greater than the change in torque current X1 in the previous impact for a predetermined number of consecutive times.

[0090] If the travel distance measuring device 3 does not determine, for a predetermined number of consecutive times, that the change A1 of the torque current X1 in the preceding impact is greater than the change A1 of the torque current X1 in the previous impact (ST2c is "No"), the travel distance measuring device 3 again measures the change A1 of the torque current X1 in the following time period (ST1) from the moment the hammer 22 impacts the anvil 23 until the hammer 22 impacts the anvil 23 again. In other words, if the travel distance measuring device 3 does not determine, for a predetermined number of consecutive times, that the change A1 of the torque current X1 in the preceding impact is greater than the change A1 of the torque current X1 in the previous impact (ST2c is "No"), the travel distance measuring device 3 measures the change A1 of the torque current X1 in the next impact.

[0091] In contrast, if the travel distance measuring device 3 determines, after a predetermined number of consecutive predetermined number of times, that the change A1 of the torque current X1 in the preceding impact is greater than the change A1 of the torque current X1 in the previous impact ("Yes" in ST2c), the travel distance measuring device 3 executes the travel distance measuring step ST3, which is used to measure the hammer travel distance based on the change A1 of the torque current X1 in the preceding impact. That is, in the travel distance measuring step ST3, the travel distance measuring device 3 measures parameters related to the hammer travel distance, wherein when the hammer 22 impacts the anvil 23, the hammer 22 moves away from the anvil 23 along the axial direction D1 from the position where the hammer 22 impacts the anvil 23, covering the hammer travel distance. In the travel distance measurement step ST3, the travel distance measuring device 3 measures the distance traveled by the hammer 22 as it moves away from the anvil 23 along the axial direction D1 from the position where the hammer 22 impacts the anvil 23. Then, in the rotation speed measurement step ST4, the rotation speed measuring device 4 measures the rotation speed of the hammer 22.

[0092] Then, in the torque estimation step ST5, the torque estimation unit 5 estimates a torque value representing the magnitude of the torque generated at the anvil 23 by the preceding impact, based on the hammer travel distance measured by the travel distance measuring device 3 in the travel distance measurement step ST3 and the rotation speed measured by the rotation speed measuring device 4 in the rotation speed measurement step ST4. In other words, in the torque estimation step ST5, the torque estimation unit 5 estimates a torque value representing the magnitude of the torque generated at the anvil 23 by the preceding impact, based at least on parameters related to the hammer travel distance.

[0093] After torque estimation step ST5, the travel distance measuring device 3 again measures the change A1 (ST1) of torque current X1 during the time period from when hammer 22 impacts anvil 23 until the next impact of hammer 22 on anvil 23. In other words, after torque estimation step ST5, travel distance measuring device 3 measures the change A1 of torque current X1 in the next impact. Afterwards, the impact rotating tool 100 does not execute judgment step ST2, but instead executes travel distance measurement step ST3, rotation speed measurement step ST4, and torque estimation step ST5 to estimate the torque value. That is, if the impact rotating tool 100 determines in the third judgment step ST2c, after the operator begins tightening work, that the travel distance measuring device 3 has determined for a predetermined number of consecutive times that the change A1 of torque current X1 in the immediate impact is greater than the change A1 of torque current X1 in the previous impact, the impact rotating tool 100 does not execute judgment step ST2. The impact rotary tool 100 repeats the following steps: ST1, ST3, ST4, ST5, to measure the change in torque value, until the operator finishes the tightening operation.

[0094] (4) Variations

[0095] The above embodiments are merely examples of various embodiments of the present invention. Various modifications can be made to the above embodiments according to design, etc., as long as the purpose of the present invention is achieved. Furthermore, functions similar to those of the travel distance measuring device 3, rotation speed measuring device 4, torque estimation unit 5, and controller 6 of the impact rotary tool 100 according to the above embodiments can be implemented, for example, by a computer program or a non-transient recording medium recording the program. According to one aspect, the program is configured to cause the computer system to execute the torque estimation method in the above embodiments.

[0096] In the above embodiment, the change A1 of torque current X1 during the time period from the time T1a when the hammer 22 impacts the anvil 23 until the time T2a when the hammer 22 impacts the anvil 23 again is defined as the difference between the local minimum V1a at time T1a and the local maximum V1b at time T1b. However, the change A1 of torque current X1 during the time period from the time T1a when the hammer 22 impacts the anvil 23 until the time T2a when the hammer 22 impacts the anvil 23 again can be defined as the difference between the local maximum V1b at time T1b and the local minimum V2a at time T2a. That is, the change A1 of torque current X1 during the time period from the time the hammer 22 impacts the anvil 23 until the next time the hammer 22 impacts the anvil 23 can be defined as the difference between the local maximum when the hammer 22 retreats to its maximum extent and the local minimum when the hammer 22 impacts the anvil 23 again.

[0097] The travel distance measuring device 3 of the above embodiment measures the hammer travel distance based on the change A1 of the torque current X1 thus measured. However, the travel distance measuring device 3 can measure the hammer travel distance by measuring the hammer travel distance. That is, the travel distance measuring device 3 may include a position sensor configured to measure the distance traveled by the hammer 22 away from the anvil 23 along the axial direction of the drive shaft 21 when the hammer 22 impacts the anvil 23.

[0098] Furthermore, in the above embodiment, the travel distance measuring device 3 measures the hammer travel distance itself as a parameter related to the hammer travel distance. However, the travel distance measuring device 3 can also measure the change A1 of the torque current X1 as a parameter related to the hammer travel distance. That is, the torque estimation unit 5 in the above embodiment estimates the torque value based on the hammer travel distance and the rotation speed of the hammer 22. However, the torque estimation unit 5 can estimate the torque value based on the change A1 of the torque current X1 and the rotation speed of the hammer 22. More specifically, a learned model is generated by performing machine learning on the torque value in advance, wherein both the change A1 of the torque current X1 and the rotation speed of the hammer 22 are feature quantities, and the torque estimation unit 5 can estimate the torque value based on the change A1 of the torque current X1 measured by the travel distance measuring device 3 and the rotation speed measured by the rotation speed measuring device 4 according to the learned model. In summary, when the torque estimation unit 5 estimates the torque value, it does not necessarily need to measure the hammer travel distance based on the change A1 of the torque current X1, but can directly estimate the torque value based on the change A1 of the torque current X1. That is to say, the "parameter related to the hammer travel distance" used in this invention can be the hammer travel distance itself, or it can be a value that changes based on the hammer travel distance (e.g., the change A1 of the torque current X1).

[0099] Furthermore, in the above embodiment, the travel distance measuring device 3 performs multiple measurements of the change in torque current X1 A1 during a machining operation. If the change in torque current X1 A1 shows an increasing trend during these multiple measurements, the travel distance measuring device 3 measures the hammer travel distance. However, the travel distance measuring device 3 can also measure the hammer travel distance after the hammer has applied a predetermined number of impacts to the anvil during a machining operation. More specifically, the travel distance measuring device 3 counts the number of impacts the hammer applies to the anvil after the tightening operation begins, and if this number reaches a predetermined number, the travel distance measuring device 3 can measure the hammer travel distance. As used herein, the "predetermined number of impacts" is set empirically, and for example, ten times. That is, when the "predetermined number of impacts" is set to ten times, the travel distance measuring device 3 counts the number of impacts the hammer applies to the anvil after the tightening operation begins, and if this number reaches ten times, the travel distance measuring device 3 measures the hammer travel distance. Note that the "predetermined number of impacts" is not limited to ten times. This configuration has the following advantages: the travel distance measuring device 3 measures the hammer travel distance with further improved accuracy without performing complex judgment processing.

[0100] The rotational speed measuring device 4 in the above embodiment measures the rotational speed of the hammer 22, but it can also measure the rotational speed of the drive shaft 21. That is, the rotational speed measuring device 4 measures at least the rotational speed of at least one of the drive shaft 21 and the hammer 22. Furthermore, the torque estimation unit 5 estimates at least a torque value representing the magnitude of the torque generated at the anvil 23 by the impact applied by the hammer 22 to the anvil 23 based on the distance the hammer travels and the rotational speed of at least one of the drive shaft 21 and the hammer 22.

[0101] The torque estimation unit 5 in the above embodiment estimates a torque value representing the magnitude of the torque generated at the anvil 23 by the impact applied by the hammer 22 to the anvil 23 based on the hammer travel distance measured by the travel distance measuring device 3 and the rotation speed measured by the rotation speed measuring device 4. However, the torque estimation unit 5 can also estimate a torque value based on the hammer travel distance measured by the travel distance measuring device 3 and the set value R1 of the rotation speed of the drive 1 preset by the operator (see [link to relevant documentation]). Figure 3 The torque estimation unit 5 estimates a torque value representing the magnitude of the torque generated at the anvil 23 by the impact applied by the hammer 22 to the anvil 23, based on the calculated rotational speed of at least one of the drive shaft 21 and the hammer 22. That is, the rotational speed of at least one of the drive shaft 21 and the hammer 22 can be measured by the rotational speed measuring device 4, or calculated by the set value R1 of the rotational speed of the drive 1. In summary, the impact rotary tool 100 does not necessarily include the rotational speed measuring device 4, and the torque estimation unit 5 estimates a torque value representing the magnitude of the torque generated at the anvil 23 by the impact applied by the hammer 22 to the anvil 23, based at least on the hammer travel distance measured by the travel distance measuring device 3.

[0102] (Summarize)

[0103] The impact rotary tool (100) according to the first aspect includes a driver (1), a drive shaft (21), a hammer (22), an anvil (23), a travel distance measuring device (3), and a torque estimation unit (5). The driver (1) is configured to perform a rotational operation. The drive shaft (21) is configured to rotate by the driver (1). The hammer (22) is configured to be mounted on the outer periphery of the drive shaft (21) such that the hammer (22) can move in the axial direction (D1) of the drive shaft (21) and can rotate in the rotational direction of the drive shaft (21). The anvil (23) is configured to receive the impact applied by the hammer (22) in the rotational direction. The travel distance measuring device (3) is configured to measure parameters related to the hammer travel distance, wherein when the hammer (22) impacts the anvil (23), the hammer (22) moves axially away from the anvil (23) from the position where the hammer (22) impacts the anvil (23) by the distance traveled. The torque estimation unit (5) is configured to estimate the torque value generated by the impact, at least based on the parameters related to the hammer travel distance.

[0104] This aspect has the advantage of being able to accurately estimate torque values.

[0105] The impact rotary tool (100) of the second aspect of the first aspect also includes a rotational speed measuring device (4). The rotational speed measuring device (4) is configured to measure the rotational speed of at least one of the drive shaft (21) and the hammer (22). The torque estimation unit (5) is configured to estimate the torque value based on parameters related to the distance traveled by the hammer and the rotational speed.

[0106] This aspect has the following advantages: the torque value can be estimated with further improved accuracy by taking into account the change in the rotational speed of at least one of the drive shaft (21) and the hammer (22).

[0107] The impact rotary tool (100) referring to the first or second aspect of the third aspect also includes a controller (6) configured to control the driver (1) according to vector control. The driver (1) is configured to be supplied with torque current (X1) according to the vector control performed by the controller (6). The travel distance measuring device (3) is configured to: measure the change (A1) of torque current (X1) during the time period from when the hammer (22) impacts the anvil (23) until the next time the hammer (22) impacts the anvil (23); and measure the hammer travel distance itself as a parameter related to the hammer travel distance, which is measured based on the change (A1).

[0108] This has the following advantages: it can accurately estimate the torque value without the need for an additional sensor to sense the distance the hammer travels.

[0109] In the impact rotary tool (100) of the fourth aspect of the third aspect, the travel distance measuring device (3) is configured to perform multiple measurements of the change (A1) in a machining operation. The travel distance measuring device (3) is configured to measure the hammer travel distance when the change (A1) shows an increasing trend in multiple measurements.

[0110] This approach has the following advantages: it measures the hammer travel distance with further improved accuracy based on the change (A1) in torque current (X1).

[0111] In the fifth aspect of the impact rotary tool (100) referring to the fourth aspect, the travel distance measuring device (3) is configured to determine that the change (A1) shows an increasing trend when the change (A1) increases continuously a predetermined number of times in multiple measurements.

[0112] This has the following advantages: regardless of the fastening components or the material of the fastening components, the distance traveled by the hammer is measured with further improved accuracy.

[0113] In the impact rotary tool (100) of the sixth aspect of the third aspect, the travel distance measuring device (3) is configured to measure the travel distance of the hammer after the hammer (22) has applied a predetermined number of impacts to the anvil (23) in a machining operation task.

[0114] This has the following advantages: the travel distance measuring device (3) measures the hammer travel distance with further improved accuracy without the need for complex judgment processing.

[0115] The seventh aspect of the torque estimation method is a torque estimation method for estimating the torque value generated by an impact applied by an impact rotating tool, which includes a driver (1), a drive shaft (21), a hammer (22), and an anvil (23). The driver (1) is configured to perform a rotational operation. The drive shaft (21) is configured to rotate by the driver (1). The hammer (22) is configured to be mounted on the outer periphery of the drive shaft (21) such that the hammer (22) is movable in the axial direction (D1) of the drive shaft (21) and can rotate in the rotational direction of the drive shaft (21). The anvil (23) is configured to receive the impact applied by the hammer (22) in the rotational direction. The torque estimation method includes a travel distance measurement step (ST3) and a torque estimation step (ST5). The travel distance measurement step (ST3) includes measuring parameters related to the hammer travel distance, wherein when the hammer (22) impacts the anvil (23), the hammer (22) travels the distance along the axial direction (D1) away from the anvil (23) from the position where the hammer (22) impacts the anvil (23). The torque estimation step (ST5) includes estimating the torque value generated by the impact based at least on the parameters related to the hammer travel distance.

[0116] This has the following advantages: it enables accurate estimation of torque values ​​without the need for a dedicated impact rotation tool (100).

[0117] The non-transient recording medium of the eighth aspect is a non-transient recording medium storing a program configured to cause the computer system to execute the torque estimation method of the seventh aspect.

[0118] This has the advantage of being able to accurately estimate torque values.

Claims

1. An impact rotary tool, comprising: A driver configured to perform a rotational operation; A drive shaft, which is configured to be rotated by the driver; A hammer, configured to be mounted on the outer periphery of the drive shaft, such that the hammer is movable in the axial direction of the drive shaft and rotatable in the rotational direction of the drive shaft. An anvil, configured to receive impacts in the rotational direction applied by the hammer; A travel distance measuring device is configured to measure parameters related to the travel distance of a hammer, wherein when the hammer impacts the anvil, the hammer travels the distance from the anvil along the axial direction from the position where the hammer impacts the anvil; A torque estimation unit is configured to estimate the torque value generated by the impact based at least on the parameters; as well as A controller configured to control the driver based on vector control. The driver is configured to be supplied with torque current according to vector control performed by the controller, and The travel distance measuring device is configured as follows: The change in torque current is measured during the time period from the moment the hammer impacts the anvil until the next time the hammer impacts the anvil. The distance traveled by the hammer is itself measured as the parameter, wherein the distance traveled by the hammer is measured based on the change.

2. The impact rotary tool according to claim 1 further includes a rotational speed measuring device, the rotational speed measuring device being configured to measure the rotational speed of at least one of the drive shaft and the hammer. in, The torque estimation unit is configured to estimate the torque value based on parameters related to the distance the hammer travels and the rotational speed.

3. The impact rotary tool according to claim 1 or 2, wherein, The travel distance measuring device is configured as follows: The change was measured multiple times in a machining operation task, and If the change shows an increasing trend in the multiple measurements, the distance traveled by the hammer is measured.

4. The impact rotary tool according to claim 3, wherein, The travel distance measuring device is configured to determine that the change shows an increasing trend when the change increases continuously a predetermined number of times in the multiple measurements.

5. The impact rotary tool according to claim 1 or 2, wherein, The travel distance measuring device is configured to measure the travel distance of the hammer in a machining operation after the hammer has impacted the anvil a predetermined number of times.

6. A torque estimation method for estimating torque values ​​generated by an impact-rotating tool, the impact-rotating tool comprising: drive, It is configured to perform rotational operations; A drive shaft, which is configured to be rotated by the driver; A hammer, configured to be mounted on the outer periphery of the drive shaft such that the hammer is movable in the axial direction of the drive shaft and rotatable in the rotational direction of rotation of the drive shaft; and an anvil, configured to receive an impact in the rotational direction applied by the hammer, the torque value being generated by the impact, the torque estimation method comprising: The travel distance measurement step is used to measure parameters related to the travel distance of the hammer, wherein when the hammer impacts the anvil, the hammer moves away from the anvil along the axial direction from the position where the hammer impacts the anvil, covering the distance traveled by the hammer. A torque estimation step is used to estimate the torque value generated by the impact based at least on the parameters; Control steps for controlling the driver according to vector control. The driver is configured to be supplied with torque current according to the vector control performed in the control step, and The travel distance measurement steps include: The change in torque current is measured during the time period from the moment the hammer impacts the anvil until the next time the hammer impacts the anvil. The distance traveled by the hammer is itself measured as the parameter, wherein the distance traveled by the hammer is measured based on the change.

7. A non-transient recording medium having a program recorded thereon, the program being configured to cause a computer system to execute the torque estimation method according to claim 6.

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