Impact rotary tool, torque calculation method, and program

Abstract

The present invention aims to accurately calculate a tightening torque at the time of tightening a fastening component. An impact rotary tool (1) includes a drive source, an impact force generating section, an output shaft, a torque measuring unit, and a torque calculating section (141). The impact force generating section is configured to generate an impact force in a pulse form from a power of the drive source. The output shaft is configured to transmit the impact force to a front end tool. The torque measuring unit (11) is configured to measure a torque applied to the output shaft. The torque calculating section (141) is configured to calculate a tightening torque from a maximum peak value among one or more second or subsequent peak values in a case where a torque waveform of the torque measured by the torque measuring unit during one impact includes a plurality of peak values.

Description

TECHNICAL FIELD

[0001] The present application relates generally to an impact rotary tool, a torque calculation method, and a program, and particularly to an impact rotary tool configured to generate an impact force in a pulse form from power of a drive source, a torque calculation method for calculating a tightening torque of the impact rotary tool, and a program configured to cause one or more processors to execute the torque calculation method. BACKGROUND

[0002] Patent Literature 1 describes an impact rotary tool in which the number of hits (impacts) applied to an output shaft by an impact mechanism is counted, and rotation of a motor (drive source) is stopped when the number of impacts thus counted reaches a shutdown number of impacts.

[0003] PRIOR ART DOCUMENTS

[0004] PATENT LITERATURE

[0005] Patent Literature 1: Japanese Patent Application Publication No. 2018-89704 SUMMARY

[0006] It is desirable to accurately calculate a tightening torque when an impact rotary tool tightens a fastening component such as a screw or the like.

[0007] In view of the above, it is an object of the present application to provide an impact rotary tool, a torque calculation method, and a program configured to accurately calculate a tightening torque for tightening a fastening component.

[0008] To achieve this object, an impact rotary tool according to an aspect of the present application includes a drive source, an impact force generation portion, an output shaft, a torque measurement unit, and a torque calculation portion. The impact force generation portion is configured to generate an impact force in a pulse form from power of the drive source. The output shaft is configured to transmit the impact force to a front-end tool. The torque measurement unit is configured to measure a torque applied to the output shaft. The torque calculation portion is configured to calculate a tightening torque from the torque measured by the torque measurement unit. The torque calculation portion is configured to calculate the tightening torque from a maximum peak value among one or more second or subsequent peak values in a case where a torque waveform of the torque measured by the torque measurement unit during one impact includes a plurality of peak values.

[0009] The torque calculation method according to an aspect of the present application includes a measurement step and a calculation step. The measurement step is for measuring a torque applied to an output shaft of an impact rotary tool. The impact rotary tool is configured to generate an impact force in a pulse form from a power of a drive source and transmit the impact force from the output shaft to a front-end tool. The calculation step is for calculating a tightening torque from a maximum peak value among one or more second or subsequent peak values in a case where a torque waveform of the torque measured in the measurement step during one impact includes a plurality of peak values.

[0010] The program according to an aspect of the present application is a program configured to cause one or more processors to execute the torque calculation method. BRIEF DESCRIPTION OF DRAWINGS

[0011] Figure 1 is a schematic view of an impact rotary tool according to an embodiment;

[0012] Figure 2 is a block diagram of the impact rotary tool;

[0013] Figure 3 is a graph of a curve showing a relationship between a torque waveform of the impact rotary tool and a rotation angle of an output shaft;

[0014] Figure 4 is a flowchart of a torque calculation process performed by the impact rotary tool;

[0015] Figure 5 is a flowchart of a selection process performed by the impact rotary tool;

[0016] Figure 6 is a flowchart of a cutoff frequency determination process performed by the impact rotary tool; and

[0017] Figure 7 is a graph of a curve showing a torque waveform of the impact rotary tool. DETAILED DESCRIPTION

[0018] Preferred embodiments of the present application will be described in detail below with reference to the attached drawings. Note that, in the embodiments described below, common elements are denoted by the same reference numerals, and redundant description of common elements is omitted. The embodiments described below are merely examples of various embodiments of the present application. The present embodiments can be modified in various ways as long as the objects of the present application are achieved. The drawings described in the present application are schematic views, and thus the size ratios and the thickness ratios of the components in the drawings do not necessarily reflect actual size ratios.

[0019] (1) SUMMARY

[0020] First, the impact rotary tool according to an aspect of the present application will be described with reference to Figure 1 and Figure 2To describe an outline of the impact rotary tool 1 according to the present embodiment. In the following description, a direction along the output shaft 8 is defined as a front-rear direction. A direction from the motor 2 toward the driver bit 9 is defined as the "front direction", and a direction from the driver bit 9 toward the motor 2 (driving source) is defined as the "rear direction".

[0021] As Figure 1 shown, the impact rotary tool 1 operates with power (e.g., electric power) from a power source such as a battery pack 10. Specifically, the motor 2, to which electric power is supplied from the battery pack 10, rotates and transmits a rotational driving force to the output shaft 8. In a case where a front-end tool such as the driver bit 9 is attached to the output shaft 8, the impact rotary tool 1 can attach a fastening component (e.g., a screw) to a workpiece (processing object) serving as a work object.

[0022] Further, the impact rotary tool 1 of the present embodiment includes an impact mechanism 3 (impact force generating portion) configured to generate an impact force in the form of a pulse. When a load torque of the output shaft 8 exceeds a prescribed level, the impact mechanism 3 exerts an impact force in the rotational direction on the output shaft 8. The output shaft 8 to which the impact force is exerted transmits the impact force to the fastening component. In this way, the impact rotary tool 1 can impart an increased tightening torque to the fastening component. Examples of the impact rotary tool 1 include various types of tools such as an impact driver and an impact wrench. The impact rotary tool 1 of the present embodiment is an impact driver including the output shaft 8 to which the driver bit 9 is attachable.

[0023] As Figure 2 shown, the impact rotary tool 1 of the present embodiment includes a torque measurement unit 11 and a torque calculation portion 141. The torque measurement unit 11 measures a torque exerted on the output shaft 8. The torque calculation portion 141 calculates a tightening torque from the torque measured by the torque measurement unit 11.

[0024] The torque measurement unit 11 of the present embodiment also measures a torque waveform of the torque exerted on the output shaft 8 during each impact exerted on the output shaft 8. Further, in a case where the torque waveform measured by the torque measurement unit 11 includes a plurality of peaks, the torque calculation portion 141 of the present embodiment calculates the tightening torque from a maximum peak among one or more second or subsequent peaks.

[0025] The impact rotary tool 1 of the present embodiment calculates the tightening torque from one or more second or subsequent peaks, rather than from a first peak for which a possibility that the torque is not transmitted to the front-end tool is high, thereby improving accuracy of the tightening torque calculation.

[0026] (2) Structure of impact rotary tool

[0027] The following will be described with reference to Figures 1 to 3The detailed structure of the impact rotary tool 1 according to the present embodiment will be described.

[0028] As shown in Figure 1 , the rechargeable battery pack 10 is detachably attached to the impact rotary tool 1. The impact rotary tool 1 of the present embodiment is operated by using the battery pack 10 as a power source. That is, the battery pack 10 is a power source that supplies electric current for driving the motor 2. The battery pack 10 is not a constituent element of the impact rotary tool 1. However, the impact rotary tool 1 can include the battery pack 10. The battery pack 10 includes an assembled battery including a plurality of secondary batteries (for example, lithium ion batteries) connected in series to each other, and a case that accommodates the assembled battery.

[0029] As shown in Figure 1 , the impact rotary tool 1 includes the motor 2, the impact mechanism 3, the output shaft 8, the torque measurement unit 11, the rotation measurement unit 12, and the trigger controller 13.

[0030] The trigger controller 13 is an operation unit that receives an operation for controlling the rotation of the motor 2. A pulling operation given to the trigger controller 13 switches the ON / OFF of the motor 2. Further, based on the amount of pulling of the trigger controller 13 by the pulling operation, the rotation speed of the motor 2 is adjustable. As the amount of pulling increases, the rotation speed of the motor 2 increases.

[0031] The motor 2 is, for example, a brushless motor. The motor 2 includes a rotation shaft 21, and converts electric power supplied from the battery pack 10 into a rotational driving force of the rotation shaft 21.

[0032] The impact mechanism 3 generates an impact force in a pulse form from the power of the motor 2. The impact mechanism 3 includes a drive shaft 31, the speed reducer 4, a hammer 5, an anvil 6, and a spring 7. The drive shaft 31 is arranged between the motor 2 and the output shaft 8.

[0033] The speed reducer 4 reduces the rotational driving force of the rotation shaft 21 of the motor 2 at a prescribed reduction ratio, and then transmits the rotational driving force to the drive shaft 31.

[0034] The hammer 5 moves relative to the anvil 6, receives power from the motor 2, and applies a rotational impact to the anvil 6. The hammer 5 is movable relative to the drive shaft 31 in the axial direction (front-rear direction) of the drive shaft 31, and is rotatable relative to the drive shaft 31. As the hammer 5 moves toward or away from the anvil 6 along the axial direction of the drive shaft 31, the hammer 5 rotates relative to the drive shaft 31. Further, the hammer 5 is rotatable relative to the spring 7.

[0035] The anvil 6 is formed integrally with the output shaft 8. The anvil 6 faces the hammer 5 in the axial direction of the drive shaft 31. In a case where the impact mechanism 3 does not perform an impact operation, the drive shaft 31, the hammer 5, and the anvil 6 rotate together.

[0036] A spring 7 is located between the speed reducer 4 and the hammer 5. The spring 7 of the present embodiment is, for example, a conical spring. The spring 7 applies a force toward the output shaft 8 (forward force) to the hammer 5 in a direction along the axial direction of the drive shaft 31.

[0037] In the following description, movement of the hammer 5 in the axial direction of the drive shaft 31 toward the anvil 6 is referred to as "forward movement of the hammer 5". In addition, in the following description, movement of the hammer 5 in the axial direction of the drive shaft 31 away from the anvil 6 is referred to as "backward movement of the hammer 5".

[0038] When the load torque is greater than or equal to a prescribed value, the impact mechanism 3 starts an impact operation. That is, as the load torque increases, the component of force generated between the hammer 5 and the anvil 6 in the direction of backward movement of the hammer 5 also increases. When the load torque is greater than or equal to the prescribed value, the hammer 5 moves backward while compressing the spring 7. Then, the hammer 5 rotates while moving backward. Thereafter, the hammer 5 receives a restoring force from the spring 7 and moves forward. Then, the hammer 5 applies a rotational impact to the anvil 6 approximately every time the drive shaft 31 rotates half a turn.

[0039] Thus, in the impact mechanism 3, the hammer 5 repeatedly applies an impact to the anvil 6. The torque generated by the impact enables fastening members such as screws, bolts, or nuts to be tightened more powerfully than in the case where no impact is applied.

[0040] A driver drill bit 9, which is a front-end tool, is attached to the output shaft 8. The output shaft 8 transmits the rotational drive force transmitted from the drive shaft 31 to the driver drill bit 9. Thus, the driver drill bit 9 rotates. The driver drill bit 9 comes into contact with a fastening member, and in this state, the driver drill bit 9 rotates, thereby tightening or loosening the fastening member. In addition, the output shaft 8 transmits a rotational impact force (impact force) transmitted from the impact mechanism 3 to the driver drill bit 9.

[0041] Note that the driver drill bit 9 can be detachably attached to the output shaft 8. In the present embodiment, the front-end tool such as the driver drill bit 9 is not a constituent element of the impact rotary tool 1. However, the front-end tool can be included in the constituent elements of the impact rotary tool 1.

[0042] The torque measurement unit 11 is, for example, a magnetostrictive distortion sensor configured to detect torsional distortion. The torque measurement unit 11 detects a change in magnetic permeability corresponding to a deformation of the output shaft 8 that occurs when a torque is applied to the output shaft 8, using a coil disposed on a non-rotating portion. Then, the torque measurement unit 11 outputs a voltage signal proportional to the distortion to the controller 14, which will be described later.

[0043] The rotation measurement unit 12 is, for example, a rotary encoder, and outputs the rotation angle of the output shaft 8 as a digital signal to the controller 14.

[0044] like Figure 2 As shown, the impact rotation tool 1 in this embodiment also includes a controller 14, a storage unit 15, and a communication unit 16.

[0045] Storage unit 15 includes, for example, a semiconductor memory. Storage unit 15 stores torque information 151 and setting information 152. Torque information 151 includes, for example, information related to the tightening torque when the impact rotary tool 1 tightens the fastening assembly. Setting information 152 includes, for example, information related to one or more operating processes and information related to a target torque associated with, for example, one or more operating processes. As mentioned in this invention, "target torque" is a target tightening torque when attaching the fastening assembly.

[0046] The communication unit 16 employs a wireless communication system conforming to standards such as Wi-Fi (registered trademark), Bluetooth (registered trademark), ZigBee (registered trademark), or low-power radio (a specific type of low-power radio) (whose use does not require a license). The communication unit 16 communicates wirelessly with the setup terminal 100, which will be described later. However, the communication unit 16 can also communicate with the setup terminal 100 based on a wired communication system.

[0047] Controller 14 includes a computer system comprising one or more processors and memory. One or more processors in the computer system execute programs stored in the computer system's memory, thereby implementing at least some of the functions of controller 14. The program may be stored in memory, made available via a telecommunications network such as the Internet, or provided as a non-transitory recording medium such as a memory card for storing the program.

[0048] like Figure 2 As shown, the controller 14 includes a torque calculation unit 141, a drive controller 142, a notification controller 143, and a response unit 144.

[0049] The torque calculation unit 141 performs a tightening torque calculation process to calculate the tightening torque based on the torque measured by the torque measuring unit 11. Specifically, in this embodiment, the torque calculation unit 141 calculates the tightening torque based on the torque measured by the impact mechanism 3 (see...). Figure 1 For output shaft 8 (see...) Figure 1 Tightening torque of each impact applied.

[0050] Figure 3 The diagram shows the torque measurement unit 11 (see...) Figure 2 The torque waveform G1 measured during a single impact is compared with that measured by the rotation measurement unit 12 (see...).Figure 2 )Measured output shaft 8 (see Figure 1 A graph showing the relationship between the rotation angle G2 and the rotation angle G2. (e.g.) Figure 3 As shown, the torque waveform G1 in each impact includes multiple (in) Figure 3 The example shown illustrates the case of two peaks. Figure 3 In the example shown, the torque waveform includes two peaks, peak P1 and peak P2. As mentioned in this invention, "peak" means a maximum value, which is a value in the torque waveform that is greater than or equal to a predetermined value. In cases where the torque waveform measured during an impact includes multiple peaks, the torque calculation unit 141 of this embodiment calculates based on the maximum peak value among one or more second or subsequent peaks (in...). Figure 3 The example shown uses peak value P2 to calculate the tightening torque. In cases where the torque waveform includes multiple peaks, the first peak value (in...) Figure 3 In the example shown, the timing of the peak value P1 is when the gap (backlash) between the output shaft 8, the front tool, and the fastening assembly is likely to be filled and the torque is not transmitted to the fastening assembly. Therefore, the torque calculation unit 141 does not calculate the tightening torque based on the first peak value.

[0051] Furthermore, at the point where the output shaft 8 switches from the fastening direction to the reverse direction, the state of applying torque to the output shaft 8 changes to a state of not applying torque to the output shaft 8. Figure 3 In the example shown, at timing T10, the state of applying torque to output shaft 8 changes to the state of not applying torque to output shaft 8. Therefore, the torque applied to output shaft 8 at the time point corresponding to timing T10 can be considered as the actual tightening torque. Here, timing T10 is at the second or subsequent time point of torque waveform G1 (in... Figure 3 The example shown is near the timing T2 of the peak P2 of the second mountain (M2). That is, Figure 3 It is shown that it is appropriate to calculate the tightening torque based on the peak value P2 of the second or subsequent peak M2.

[0052] On the other hand, at the time T1 of the peak P1 of the first mountain M1, the rotation angle G2 is increasing. That is to say, Figure 3 It is shown that it is inappropriate to calculate the tightening torque based on the peak value P1 of the first mountain M1.

[0053] As described above, the impact rotary tool 1 of this embodiment does not calculate the tightening torque based on the first peak included in the torque waveform measured during a single impact, where the torque is highly likely not transmitted to the front tool. Therefore, the impact rotary tool 1 of this embodiment can improve the accuracy of tightening torque calculation.

[0054] Details of the tightening torque calculation processing will be described in "(4) Tightening Torque Calculation Processing". Figure 2 The torque calculation section 141 illustrated outputs information on the tightening torque calculated in the tightening torque calculation processing to the drive controller 142.

[0055] The drive controller 142 controls the operation of the motor 2. When the tightening torque calculated by the torque calculation section 141 reaches the target torque, the drive controller 142 of the present embodiment stops the motor 2. The drive controller 142 of the present embodiment determines whether the tightening torque calculated by the torque calculation section 141 reaches the target torque on the basis of the target torque included in the setting information 152 stored in the storage section 15.

[0056] The notification controller 143 controls notification of information on the tightening torque calculated by the torque calculation section 141. The notification controller 143 of the present embodiment causes the display unit 101 (communication device) of the setting terminal 100 to display information on the tightening torque via the communication section 16. Note that the notification controller 143 can cause a speaker (communication device) to output information on the tightening torque in voice. Further, in the case where the impact rotary tool 1 includes a display unit and / or a speaker as the communication device(s), the notification controller 143 can cause the display unit and / or the speaker included in the impact rotary tool 1 to perform notification of information on the tightening torque. Further, the notification controller 143 can, for example, notify a work process and / or notify a target torque value corresponding to the work process.

[0057] The reflection unit 144 reflects the torque information 151 stored in the storage section 15 in settings related to tightening of the fastening assembly by the impact rotary tool 1. In other words, the reflection unit 144 reflects past work data in settings related to tightening of the fastening assembly. For example, in the case where the torque information 151 is associated with the type of the fastening assembly, the target torque, and the number of impacts (strikes) at the time when the tightening torque reaches the target torque, the impact rotary tool 1 can also perform torque management by managing the number of impacts in accordance with the type of the fastening assembly and the target torque. That is, for example, the output of the motor 2 can be adjusted more appropriately in accordance with the fastening assembly. Further, since past work data is reflected in settings related to tightening of the fastening assembly, it is possible to reduce the time and effort of the worker in providing settings related to tightening of the fastening assembly.

[0058] (3) Structure of Setting Terminal

[0059] The detailed structure of the setting terminal 100 according to the present embodiment will be described below with reference to Figure 2

[0060] ​The setting terminal 100 is, for example, an information terminal such as a personal computer (PC), a smart phone, or a tablet computer. As shown in FIG. 1, the setting terminal 100 includes a display unit 101, an operation unit 102, a communication section 103, and a controller 104. Figure 2

[0061] The communication section 103 employs a wireless communication system conforming to a standard such as Wi-Fi (registered trademark), Bluetooth (registered trademark), ZigBee (registered trademark), or low power radio (specific low power radio) which uses no license. The communication section 103 performs wireless communication with the impact rotary tool 1 which will be described later. However, the communication section 103 can communicate with the impact rotary tool 1 based on a wired communication system.

[0062] The display unit 101 and the operation unit 102 can be, for example, a touch panel display which is integrally formed. The display unit 101 of the present embodiment displays information relating to the tightening torque in response to an instruction given by the notification controller 143 of the impact rotary tool 1.

[0063] The controller 104 includes a computer system including one or more processors and a memory. The processor(s) in the computer system execute a program stored in the memory of the computer system, thereby realizing at least some of the functions of the controller 104. The program can be stored in the memory, can be provided through a telecommunication network such as the Internet, or can be provided as a non-transitory recording medium such as a memory card storing the program. The controller 104 is configured to control the display unit 101, the operation unit 102, and the communication section 103.

[0064] (4) Tightening Torque Calculation Processing

[0065] Details of the tightening torque calculation processing (torque calculation method) will be described below with reference to Figures 4 to 7

[0066] Figure 4 is a flowchart showing the procedure of the tightening torque calculation processing. First, the torque calculation section 141 performs first filtering on the torque waveform of the torque measured by the torque measurement unit 11 (S1). In the first filtering, the torque calculation section 141 cuts off noise of a high frequency component by using a low-pass filter having a prescribed cutoff frequency. Here, the prescribed cutoff frequency is a frequency higher than the cutoff frequency of the low-pass filter used in the second filtering which will be described later.

[0067] Then, the torque calculation section 141 performs first selection processing (S2). The first selection processing is processing for selecting a peak value included in the torque waveform to determine the cutoff frequency of the low-pass filter used in the second filtering. Figure 5 ​​is a flowchart of the first selection process (S2) and the second selection process (S5) to be described later. The torque calculation portion 141 searches for the start point and the end point of the entire torque waveform (Sll). Specifically, the torque calculation portion 141 searches for an inflection point from the initial rise of the entire torque waveform as the start point of the entire torque waveform, and searches for an inflection point from the final descent of the entire torque waveform as the end point of the entire torque waveform. Then, the torque calculation portion 141 searches for the largest peak value in the entire torque waveform, and temporarily selects the peak value (S12). In other words, the torque calculation portion 141 searches for a global maximum value of the entire torque waveform. Next, the torque calculation portion 141 searches for the start point and the end point of a hill including the temporarily selected peak value (S13). The "hill" as mentioned in the present application is a hill-shaped (convex) portion of the torque waveform in which a peak value is assumed to be an apex, the hill-shaped portion having a start point as an ascending point and an end point as a descending point. The torque calculation portion 141 of the present embodiment searches for the start point and the end point of the hill by searching for inflection points adjacent to the temporarily selected peak value. Specifically, among two inflection points adjacent to the temporarily selected peak value in the torque waveform, the inflection point before the temporarily selected peak value is the start point of the hill, and the inflection point after the temporarily selected peak value is the end point of the hill.

[0068] After the torque calculation portion 141 searches for the start point and the end point of the hill, the torque calculation portion 141 compares the start point of the entire torque waveform with the start point of the hill, thereby determining a time difference (S14). If the time difference between the start point of the entire torque waveform and the start point of the hill is greater than or equal to a threshold value Thl (see Figure 7 )(YES in S15), the torque calculation portion 141 determines that the hill including the temporarily selected peak value is a second or subsequent hill (S16). The "second or subsequent hill" means other than the first hill. In a case where the torque calculation portion 141 determines that the hill including the temporarily selected peak value is a second or subsequent hill, the torque calculation portion 141 determines the temporarily selected peak value as the maximum peak value (S17). Once the torque calculation portion 141 determines the maximum peak value, the torque calculation portion 141 ends the first selection process (S2).

[0069] On the other hand, if the time difference between the start point of the entire torque waveform and the start point of the hill is less than the threshold value Thl in the process of step S15 (NO in S15), the torque calculation portion 141 compares the end point of the entire torque waveform with the end point of the hill, thereby determining a time difference (S18). If the time difference between the end point of the entire torque waveform and the end point of the hill is less than a threshold value Th2 (see Figure 7(S19), the torque calculating section 141 judges that the torque waveform includes only a mountain including the temporarily selected peak value (S20). In other words, the torque calculating section judges that the entire torque waveform is one mountain. If the torque waveform includes only one peak value, the torque calculating section 141 of the present embodiment calculates the tightening torque from the one peak value. In the case where the torque calculating section 141 judges that the entire torque waveform is one mountain, the torque calculating section 141 determines the temporarily selected peak value as the maximum peak value (S17). Once the torque calculating section 141 determines the maximum peak value, the torque calculating section 141 ends the first selection processing (S2).

[0070] Further, in the processing of Step S19, if the time difference between the end point of the entire torque waveform and the end point of the mountain is greater than or equal to the threshold value Th2, that is, if the time difference is not less than the threshold value Th2 (NO in S19), the torque calculating section 141 judges that the mountain including the temporarily selected peak value is the first mountain (S21). In the case where the mountain including the temporarily selected peak value is the first mountain, the operation of calculating the tightening torque from the temporarily selected peak value is likely to be inappropriate. Therefore, the torque calculating section 141 excludes the temporarily selected peak value from the objects to be searched (S22), and searches for the maximum peak value again (S12). Then, the torque calculating section 141 performs the first selection processing (S2) until the torque calculating section 141 determines the maximum peak value (S17). Note that the determination of the maximum peak value by the torque calculating section 141 in the first selection processing can be referred to as "temporary determination of the maximum peak value".

[0071] After the first selection processing (S2), the torque calculating section 141 performs the cutoff frequency determination processing (S3). Figure 6 is a flowchart showing the procedure of the cutoff frequency determination processing (S3). The torque calculating section 141 calculates the width of the mountain including the maximum peak value from the start point and the end point of the mountain (S31). The "width of the mountain" as referred to in the present application is the period from the rise to the fall of the mountain. In other words, the period from the start point of the mountain to the end point of the mountain. Further, the "width of the mountain" substantially corresponds to half the period of the mountain. The torque calculating section 141 calculates the width of the mountain, and then the torque calculating section 141 determines the cutoff frequency from the width of the mountain (S32). Specifically, the torque calculating section 141 of the present embodiment determines the reciprocal of the width of the mountain as the cutoff frequency. The cutoff frequency is a frequency higher than the frequency of the mountain. Once the torque calculating section 141 determines the cutoff frequency (S32), the torque calculating section 141 ends the cutoff frequency determination processing (S3).

[0072] After the cutoff frequency determination process (S3), the torque calculating section 141 performs second filtering on the torque waveform (S4). Note that the second filtering can be performed on the torque waveform after the first filtering, or the second filtering can be performed on the torque waveform without the first filtering. In the second filtering, the torque calculating section 141 cuts off noise of a high frequency component with the cutoff frequency determined in the cutoff frequency determination process (S3). Here, the cutoff frequency determined in the cutoff frequency determination process (S3) is a frequency lower than the cutoff frequency of the low-pass filter used in the first filtering.

[0073] After the second filtering (S4), the torque calculating section 141 performs a second selection process (S5). The second selection process is a process for selecting a peak value on which the tightening torque is to be calculated from the torque waveform after the second filtering. The second selection process (S5) is the same process as the above-described first selection process (S2), and thus the description thereof is omitted. After the maximum peak value is determined in the second selection process (S5), the torque calculating section 141 calculates the tightening torque based on the maximum peak value (S6). Once the torque calculating section 141 calculates the tightening torque (S6), the torque calculating section 141 ends the tightening torque calculation process.

[0074] Next, the first selection process and the cutoff frequency determination process will be described with reference to Figure 7 . Figure 7 is a graph showing a torque waveform of the torque measured by the torque measuring unit 11 during the one impact. When the torque calculating section 141 starts the first selection process (S2 in Figure 4 ), the torque calculating section 141 searches for the start point P3 and the end point P10 of the entire torque waveform (S11 in Figure 5 ). Then, the torque calculating section 141 searches for the maximum peak value P6 in the entire torque waveform, and the torque calculating section 141 temporarily selects the peak value P6 (S12 in Figure 5 ). Note that the maximum value P4 is a maximum value of the torque waveform, but the maximum value P4 is a value smaller than a predetermined value. Thus, the maximum value P4 is not included in the "peak value" mentioned in the present application. Next, the torque calculating section 141 searches for the start point P5 and the end point P7 of the mountain M3 including the temporarily selected peak value P6 (S13 in Figure 5 ). After the start point P5 and the end point P7 of the mountain M3 are searched, the torque calculating section 141 compares the start point P3 of the entire torque waveform and the start point P5 of the mountain M3, thereby determining the time difference (T4-T3) (S14 in Figure 5 ). In the example shown in Figure 7 , the time difference (T4-T3) between the start point P3 of the entire torque waveform and the start point P5 of the mountain M3 is smaller than the threshold value Th1 (S15 in Figure 5(In S15, it is "No"). Next, the torque calculation unit 141 compares the end point P10 of the entire torque waveform with the end point P7 of M3, thereby determining the time difference (T9-T6). Figure 5 (S18 in the text). Figure 7 In the example shown, the time difference (T9-T6) between the end point P10 of the entire torque waveform and the end point P7 of M3 is greater than or equal to the threshold Th2. Figure 5 (In S19, it is "No"). Then, the torque calculation unit 141 determines that the peak M3, including the peak P6, is the first peak ( Figure 5 S21 in the middle), and exclude peak P6 ( Figure 5 (S22 in the text).

[0075] Next, the torque calculation unit 141 searches for the largest peak value P9 in the entire torque waveform, excluding peak value P6, and the torque calculation unit 141 temporarily selects peak value P9. Figure 5 (S12 in the middle). Then, the torque calculation unit 141 searches for the starting point P8 and the ending point P10 of the peak M4 including the peak P9 (in the middle). Figure 5 (S13 in the text). After finding the starting point P8 and ending point P10 of mountain M4, the torque calculation unit 141 compares the starting point P3 of the entire torque waveform with the starting point P8 of mountain M4, thereby determining the time difference (T7-T3). Figure 5 (S14 in the text). Figure 7 In the example shown, the time difference (T7-T3) between the starting point P3 and the starting point P8 of the entire torque waveform is greater than or equal to the threshold Th1. Figure 5 In S15, it is "Yes"), therefore the torque calculation unit 141 determines that the peak M4, including the peak P9, is the second or subsequent peak ( Figure 5 (S16 in the text). Then, the torque calculation unit 141 determines the temporarily selected peak value P9 as the maximum peak value ( Figure 5 S17 in the middle), and end the first selection process ( Figure 4 (S2 in the middle).

[0076] Next, the torque calculation unit 141 begins the cutoff frequency determination process. Figure 4 (S3 in the text). The torque calculation unit 141 calculates the width W1 of mountain M4 based on the starting point P8 and ending point P10 of mountain M4, which includes the maximum peak value P9. Figure 6 (S31 in the text). Then, the torque calculation unit 141 determines the cutoff frequency as the reciprocal of the width W1 of the mountain M4 (S31 in the text). Figure 6 S32 in the middle), and end the cutoff frequency determination process ( Figure 4 (S3 in the middle).

[0077] (5) Operation and advantages

[0078] As described above, the impact rotary tool 1 of the present embodiment includes the impact mechanism 3, the output shaft 8, the torque measuring unit 11, and the torque calculating section 141. In a case where the torque waveform of the torque measured by the torque measuring unit 11 during one impact includes a plurality of peaks, the torque calculating section 141 calculates the tightening torque from the maximum peak value of one or more second or subsequent peak values. Thus, the impact rotary tool 1 of the present embodiment does not calculate the tightening torque from the first peak value for which the possibility that the torque is not transmitted to the front-end tool is high, thereby improving the accuracy of the tightening torque calculation.

[0079] Further, the torque calculating section 141 of the present embodiment calculates the tightening torque after performing a process for cutting off a frequency component of a higher frequency than a hill including the maximum peak value (second filtering) on the torque waveform. Removing a high-frequency noise component superimposed on the torque waveform can further improve the accuracy of the tightening torque calculation.

[0080] Further, the torque calculating section 141 of the present embodiment temporarily selects the maximum peak value in the torque waveform (first selection process). Further, the torque calculating section 141 of the present embodiment derives a cutoff frequency from the width between the start point and the end point of the hill including the temporarily selected peak value (cutoff frequency determination process), and performs the second filtering. The torque calculating section 141 selects the maximum peak value included in the torque waveform after the second filtering (second selection process), and calculates the tightening torque from the peak value thus selected. After the maximum peak value is temporarily selected and the second filtering based on the width of the hill including the maximum peak value is performed, the tightening torque is calculated from the maximum peak value selected from the torque waveform after the second filtering, and thus the accuracy of the tightening torque calculation can be further improved.

[0081] Further, in a case where the torque waveform includes one peak value, the torque calculating section 141 of the present embodiment calculates the tightening torque from the one peak value. In a case where the torque waveform includes only one peak value, calculating the tightening torque from the one peak value can improve the accuracy of the tightening torque calculation.

[0082] Further, the impact rotary tool 1 of the present embodiment further includes a drive controller 142. In a case where the tightening torque calculated by the torque calculating section 141 reaches the target torque, the drive controller 142 stops the motor 2. Thus, the impact rotary tool 1 of the present embodiment can perform an appropriate fastening operation.

[0083] Further, the impact rotary tool 1 of the present embodiment further includes a notification controller 143. The notification controller 143 controls the notification of information about the tightening torque calculated by the torque calculating section 141, and thereby a worker or the like using the impact rotary tool 1 can verify the tightening torque.

[0084] Further, the notification controller 143 of the present embodiment causes the display unit 101 of the setting terminal 100 to display information related to the tightening torque. A worker or the like can verify the information related to the tightening torque by looking at the display unit 101 even in, for example, noise.

[0085] Further, the impact rotary tool 1 of the present embodiment further includes a storage section 15 and a reflection unit 144. The reflection unit 144 reflects the information related to the tightening torque stored in the storage section 15 in the setting related to the fastening of the work object, thereby further appropriately performing adjustment of the output of the motor 2 or the like.

[0086] (6) Modification

[0087] Modifications of the embodiments will be listed below. The modifications described below can be applied in association with the embodiments accordingly.

[0088] Further, a function equivalent to the function of the impact rotary tool 1 of the above-described embodiments can be realized, for example, by a torque calculation method, a (computer) program, or a non-transitory recording medium storing the program. The torque calculation method according to an aspect includes a measurement step and a calculation step. The measurement step includes measuring a torque applied to the output shaft 8 of the impact rotary tool 1. The impact rotary tool 1 generates an impact force in the form of a pulse from the power of the motor 2, and transmits the impact force from the output shaft 8 to the front-end tool (driver drill bit 9). The calculation step includes calculating the tightening torque from a maximum peak value among one or more second or subsequent peak values in a case where a torque waveform of the torque measured in the measurement step during one impact includes a plurality of peak values. The program according to an aspect is a program configured to cause one or more processors to execute the torque calculation method.

[0089] It is not essential to concentrate the constituent elements of the impact rotary tool 1 in one housing. The constituent elements of the impact rotary tool 1 can be distributed in a plurality of housings. For example, the torque calculation section 141 can be arranged in a housing other than the housing in which the motor 2 and the impact mechanism 3 or the like are arranged.

[0090] In the above-described embodiments, the impact rotary tool 1 is, for example, an impact driver. However, the impact rotary tool 1 is not limited to the impact driver, but can be, for example, an impact wrench.

[0091] (SUMMARY)

[0092] The impact rotary tool (1) of the first aspect includes a driving source (motor 2), an impact force generating section (impact mechanism 3), an output shaft (8), a torque measuring unit (11), and a torque calculating section (141). The impact force generating section is configured to generate an impact force in a pulse form from the power of the driving source. The output shaft (8) is configured to transmit the impact force to a front end tool (driver drill bit 9). The torque measuring unit (11) is configured to measure a torque applied to the output shaft (8). The torque calculating section (141) is configured to calculate a tightening torque from the torque measured by the torque measuring unit (11). The torque calculating section (141) is configured to calculate the tightening torque from a maximum peak value among one or more second or subsequent peak values in a case where a torque waveform of the torque measured by the torque measuring unit (11) during one impact includes a plurality of peak values.

[0093] In this aspect, the tightening torque value is not calculated based on a first peak value included in the torque waveform measured during one impact and having a high possibility that the torque is not transmitted to the front end tool (driver drill bit 9). Thus, this aspect makes it possible to accurately calculate the tightening torque.

[0094] In the impact rotary tool (1) of the second aspect with reference to the first aspect, the torque calculating section (141) is configured to perform a process on the torque waveform for cutting out a frequency component having a higher frequency than a hill including the maximum peak value, and calculate the tightening torque from the maximum peak value included in the torque waveform after the process.

[0095] With this aspect, removing a high frequency noise component superimposed on the torque waveform makes it possible to improve the accuracy of the tightening torque calculation.

[0096] In the impact rotary tool (1) of the third aspect with reference to the second aspect, the torque calculating section (141) is configured to select the maximum peak value included in the torque waveform. The torque calculating section (141) is configured to derive a cutoff frequency from a width of a hill, and perform a process on the torque waveform using the cutoff frequency. The torque calculating section (141) is configured to calculate the tightening torque from the maximum peak value included in the torque waveform after the process.

[0097] With this aspect, after temporarily selecting the maximum peak value and performing a process on the torque waveform based on the width of the hill including the maximum peak value, the tightening torque is calculated from the maximum peak value selected from the torque waveform after the process, so it is possible to further improve the accuracy of the tightening torque calculation.

[0098] In the impact rotary tool (1) of the fourth aspect with reference to any one of the first to third aspects, the torque calculating section (141) is configured to calculate the tightening torque from one peak value in a case where the torque waveform includes one peak value.

[0099] With this aspect, in a case where the torque waveform measured during one impact includes only one peak value, the tightening torque is calculated based on the one peak value, thereby improving the accuracy of the tightening torque calculation.

[0100] The impact rotary tool (1) according to a fifth aspect of any one of the first to fourth aspects further includes a drive controller (142). The drive controller (142) is configured to stop the drive source (motor 2) in a case where the tightening torque calculated by the torque calculation section (141) reaches a target torque.

[0101] With this aspect, the drive source (motor 2) is stopped in a case where the tightening torque calculated by the torque calculation section (141) reaches a target torque, which enables proper tightening operation.

[0102] The impact rotary tool (1) according to a sixth aspect of any one of the first to fifth aspects further includes a notification controller (143). The notification controller (143) is configured to control notification of information related to the tightening torque calculated by the torque calculation section (141).

[0103] With this aspect, the notification of information related to the tightening torque calculated by the torque calculation section (141) enables a worker using the impact rotary tool (1) to verify the tightening torque.

[0104] In the impact rotary tool (1) according to a seventh aspect of the sixth aspect, the notification controller (143) is configured to cause the display unit (101) to display information related to the tightening torque.

[0105] With this aspect, causing the display unit (101) to display information related to the tightening torque enables a worker or the like to verify the tightening torque even in noise.

[0106] The impact rotary tool (1) according to an eighth aspect of any one of the first to seventh aspects further includes a storage section (15) and a reflection unit (144). The storage section (15) is configured to store information related to the tightening torque calculated by the torque calculation section (141). The reflection unit (144) is configured to reflect the information stored in the storage section (15) in a setting related to tightening of a work object.

[0107] With this aspect, reflecting the information related to the tightening torque calculated by the torque calculation section (141) in the setting related to tightening of a work object enables, for example, further proper adjustment of the output of the drive source (motor 2).

[0108] Configurations other than the configuration of the first aspect are not essential configurations of the impact rotary tool (1) and thus can be omitted.

[0109] The torque calculation method of the ninth aspect includes a measurement step and a calculation step. The measurement step includes measuring a torque applied to an output shaft (8) in the impact rotary tool (1). The impact rotary tool (1) is configured to generate an impact force in a pulse form from a power of a drive source, and transmit the impact force from the output shaft (8) to a front end tool (driver drill bit 9). The calculation step includes calculating a tightening torque from a maximum peak value among one or more second or subsequent peak values in a case where a torque waveform of the torque measured in the measurement step during one impact includes a plurality of peak values.

[0110] With this aspect, the tightening torque value is not calculated from a first peak value included in the torque waveform measured during one impact and having a high possibility that the torque is not transmitted to the front end tool (driver drill bit 9), and thus the tightening torque can be accurately calculated.

[0111] The program of the tenth aspect is a program configured to cause one or more processors to execute the torque calculation method of the ninth aspect.

[0112] BRIEF DESCRIPTION OF DRAWINGS

[0113] 1 impact rotary tool

[0114] 2 motor (drive source)

[0115] 3 impact mechanism (impact force generation portion)

[0116] 8 output shaft

[0117] 9 driver drill bit (front end tool)

[0118] 11 torque measurement unit

[0119] 141 torque calculation portion

[0120] 142 drive controller

[0121] 143 notification controller

[0122] 144 reflection unit

[0123] 15 storage portion

[0124] 101 display unit

Claims

1. An impact rotary tool, comprising: a drive source; an impact force generation section configured to generate an impact force in a pulse form from power of the drive source; an output shaft configured to transmit the impact force to a front end tool; a torque measurement unit configured to measure a torque applied to the output shaft; and a torque calculation section configured to calculate a tightening torque from the torque measured by the torque measurement unit, wherein the torque calculation section is configured to calculate the tightening torque from a maximum peak value among one or more second or subsequent peak values in a case where a torque waveform of the torque measured by the torque measurement unit during one impact includes a plurality of peak values.

2. The impact rotary tool according to claim 1, wherein the torque calculation section is configured to: perform a process for cutting off a frequency component of a higher frequency than a mountain including the maximum peak value on the torque waveform, and calculate the tightening torque from a maximum peak value included in the torque waveform after the process.

3. The impact rotary tool according to claim 2, wherein the torque calculation section is configured to: select the maximum peak value included in the torque waveform, derive a cutoff frequency from a width of the mountain, perform a process using the cutoff frequency on the torque waveform, and calculate the tightening torque from a maximum peak value included in the torque waveform after the process.

4. The impact rotary tool according to any one of claims 1 to 3, wherein the torque calculation section is configured to calculate the tightening torque from one peak value in a case where the torque waveform includes one peak value.

5. The impact rotary tool according to any one of claims 1 to 3, further comprising a drive controller configured to stop the drive source in a case where the tightening torque calculated by the torque calculation section reaches a target torque.

6. The impact rotary tool according to any one of claims 1 to 3, further comprising a notification controller configured to control notification of information about the tightening torque calculated by the torque calculation section.

7. The impact rotary tool according to claim 6, wherein the notification controller is configured to cause a display unit to display the information about the tightening torque.

8. The impact rotary tool according to any one of claims 1 to 3, further comprising: a storage section configured to store information about the tightening torque calculated by the torque calculation section; and a reflection unit configured to reflect the information stored in the storage section in a setting related to fastening of a work object.

9. A torque calculation method, comprising: a measurement step of measuring a torque applied to an output shaft of an impact rotary tool configured to generate an impact force in a pulse form from power of a drive source and transmit the impact force from the output shaft to a front end tool; and a calculation step of calculating a tightening torque from the torque measured in the measurement step. ​ ​ a calculation step for calculating the tightening torque from the maximum peak value of one or more second or subsequent peak values in the case where the torque waveform of the torque measured in the measurement step during one impact comprises a plurality of peak values.

10. A non-transitory storage medium having stored thereon a program configured to cause one or more processors to perform the torque calculation method according to claim 9.

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