Power tool

Abstract

To improve convenience.SOLUTION: A power tool 1 includes a motor 111, a control part 12, and a gas detection part 15. The control part 12 controls a rotation operation of the motor 111. The gas detection part 15 detects combustible gas. The control part 12 has a normal mode and a gas leakage mode as operation modes. The gas leakage mode starts in response to the fact that the combustible gas is detected by the gas detection part 15. In the gas leakage mode, the control part 12 performs control different from that in the normal mode.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates generally to power tools. [Background technology]

[0002] Patent Document 1 describes an electric load shutdown system.

[0003] The electric load operation stop system of Patent Document 1 includes a plurality of electric load control devices, each of which has a detection means, a switching means, and a control means.

[0004] The switching means is switchable between a first state that permits operation of the electric load operated by power supply from the power source and a second state that restricts operation of the electric load. The detection means detects the gas concentration of the flammable gas. The control means controls the switching means based on the gas concentration detected by the detection means.

[0005] The electric load control devices are electrically connected to each other. Each of the control means has a determination means for determining whether or not the gas concentration detected by the corresponding detection means exceeds a predetermined concentration, and when the gas concentration is determined to exceed the predetermined concentration by the control means or another determination means, the control means controls the corresponding switching means to switch from the first state to the second state. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2019-74854 A Summary of the Invention [Problem to be solved by the invention]

[0007] The electric load operation / stop system described in Patent Document 1 is provided separately from the electric load. Therefore, it needs to be prepared separately from the electric load, which may be inconvenient for users.

[0008] The present disclosure has been made in consideration of the above problems, and aims to improve convenience. [Means for solving the problem]

[0009] An electric power tool according to one aspect of the present disclosure includes a motor, a controller, and a gas detector. The controller controls a rotational operation of the motor. The gas detector detects a flammable gas. The controller has a normal mode and a gas leakage mode as operation modes. The gas leakage mode is initiated in response to detection of the flammable gas by the gas detector, and is an operation mode in which control different from that in the normal mode is performed. Effect of the Invention

[0010] The present disclosure has the advantage of making it possible to improve convenience. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is a block diagram of a power tool according to one embodiment. [Diagram 2] FIG. 2 is a perspective view of the electric power tool as viewed from the front. [Diagram 3] FIG. 3 is a perspective view of the electric power tool as viewed from the rear. [Figure 4] FIG. 4 is a flowchart showing an example of the operation of the control unit of the power tool. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, preferred embodiments of the present disclosure will be described in detail with reference to the drawings. Each of the drawings described in the following embodiments is a schematic diagram, and the size and thickness ratios of each component in each drawing do not necessarily reflect the actual dimensional ratios. In addition, elements common to the embodiments described below are assigned the same reference numerals, and duplicated descriptions of the common elements will be omitted.

[0013] (1) Implementation form The power tool 1 of this embodiment is a device for performing a task on a work object.

[0014] The power tool 1 of this embodiment is used, for example, when performing piping work on gas pipes in a factory or a work site. The power tool 1 is used, for example, for joining gas pipes with fastening parts, or for removing joined gas pipes. More specifically, the power tool 1 is used, for example, for joining flanges of two gas pipes together by fastening fastening parts, or for removing gas pipes by loosening fastening parts that join the flanges of the gas pipes together. In this case, the work target of the power tool 1 includes fastening parts and gas pipes (flanges). The fastening parts may include bolts and nuts.

[0015] An example of a power tool 1 used for this type of work is an electric impact wrench that tightens or loosens fastening parts by applying an impact force. Note that the power tool 1 is not limited to an electric impact wrench, and may be an electric impact driver, or an electric torque wrench or electric drill driver that does not apply an impact force. Such a power tool 1 is capable of tightening or loosening fastening parts such as bolts, nuts, and screws.

[0016] In this embodiment, it is assumed that the power tool 1 is an impact wrench.

[0017] 1, the power tool 1 includes a drive unit 11, a control unit 12, a transmission mechanism 13, an imaging unit 14, a gas detection unit 15, a notification unit 16, and a battery pack 201. In this embodiment, the battery pack 201 is included in the components of the power tool 1, but it is not essential that the battery pack 201 be included in the components of the power tool 1, and the components of the power tool 1 do not necessarily need to include the battery pack 201.

[0018] 2 and 3, the power tool 1 further includes a body 20. The body 20 holds or houses the drive unit 11 and the transmission mechanism 13. Furthermore, in the power tool 1 of this embodiment, the control unit 12, the gas detection unit 15, and the notification unit 16 are also held or housed in the body 20.

[0019] As shown in Figs. 2 and 3, the body 20 of the power tool 1 has a body portion 21, a grip portion 22, and an attachment portion 23. The body portion 21 is formed in a tubular shape (here, cylindrical). The grip portion 22 protrudes from a part of the circumferential surface of the body portion 21 along a normal direction (radial direction of the body portion 21). The attachment portion 23 is provided so that the battery pack 201 can be removably attached thereto. The attachment portion 23 is provided at the tip portion of the grip portion 22. In other words, the body portion 21 and the attachment portion 23 are connected by the grip portion 22.

[0020] At least the drive unit 11 is housed in the body 21. The drive unit 11 is configured to operate using power (electrical energy) supplied from a battery pack 201, which is a power source. The drive unit 11 has, for example, a motor 111 and a drive circuit. The motor 111 is, for example, a brushless motor. The drive circuit includes, for example, an inverter circuit, and rotates the motor 111 using the supplied power (electrical energy).

[0021] As shown in Fig. 2 and Fig. 3, the power tool 1 further includes an output shaft 241. The output shaft 241 protrudes from one end surface in the axial direction of the body 21. The output shaft 241 is configured to rotate about a rotation axis Ax1 along the protruding direction of the output shaft 241 in association with the rotation of the motor 111. That is, the output shaft 241 rotates in response to the rotation of the motor 111. In addition, the drive unit 11 drives the output shaft 241 to rotate the output shaft 241 around the rotation axis Ax1.

[0022] Specifically, the output shaft 241 is connected to the shaft of the motor 111 via the transmission mechanism 13. The transmission mechanism 13 has a speed reduction mechanism such as a planetary gear mechanism. Since the power tool 1 of this embodiment is an impact wrench, the transmission mechanism 13 further has an impact mechanism 131. The impact mechanism 131 applies an impact force in the rotational direction to the output shaft 241 when the tightening torque exceeds a predetermined level.

[0023] A tool tip 242 is removably coupled to the output shaft 241. The tool tip 242 is, for example, a cylindrical socket 243 for rotating a fastening part (for example, a bolt or a nut). The socket 243 rotates around the rotation axis Ax1 together with the output shaft 241. The size of the socket 243 attached to the output shaft 241 is appropriately selected by the user in accordance with the size of the fastening part.

[0024] With this configuration, when the motor 111 rotates, the output shaft 241 rotates and the socket 243 rotates together with the output shaft 241. At this time, if the socket 243 is fitted into a fastening part, the fastening part rotates together with the socket 243, thereby realizing an operation of fastening or loosening the fastening part.

[0025] The tip tool 242 is not limited to the socket 243, and may be, for example, a socket anvil. The socket anvil is also removably attached to the output shaft 241. In this case, a bit (for example, a driver bit or a drill bit) can be attached via the socket anvil.

[0026] In short, an end tool 242 (socket 243, socket anvil, etc.) for fastening or loosening a fastening part is connected to the output shaft 241.

[0027] The grip unit 22 is a portion that a user grips when performing work. The grip unit 22 is provided with a trigger switch 221 (operation button) and a forward / reverse changeover switch 222. The trigger switch 221 is a switch for controlling the on / off of the operation of the drive unit 11. The trigger switch 221 has an initial position and an on position, and the motor 111 rotates when the user pushes or pulls the trigger switch 221 to the on position. The trigger switch 221 can also adjust the rotation speed (also called the number of rotations) of the motor 111, that is, the rotation speed of the output shaft 241, according to the pulling amount (operation amount). The forward / reverse changeover switch 222 is a switch for switching the rotation direction of the output shaft 241 between forward rotation and reverse rotation.

[0028] The mounting section 23 is formed in a flat rectangular parallelepiped shape. A battery pack 201 is removably mounted on one surface of the mounting section 23 opposite to the grip section 22.

[0029] The battery pack 201 has a resin case 202 formed in a rectangular parallelepiped shape. The case 202 houses a storage battery (for example, a lithium ion battery). The battery pack 201 supplies power to the drive unit 11, the control unit 12, the notification unit 16, and the like.

[0030] The mounting section 23 is also provided with an operation panel 231. The operation panel 231 has, for example, a plurality of push button switches 232 and a plurality of LEDs (Light Emitting Diodes) 233. The operation panel 231 can be used to perform various settings and status confirmation related to the power tool 1. For example, by operating the push button switches 232 of the operation panel 231, the user can set an upper limit value for the rotation speed of the motor 111, check the remaining capacity of the battery pack 201, and the like.

[0031] The imaging unit 14 captures an image of a work target to generate a captured image. The imaging unit 14 is, for example, a camera having an imaging element and a lens. The imaging unit 14 is housed, for example, in the body 20 (body 21) of the power tool 1. The imaging unit 14 is mounted toward the tip of the output shaft 241 so that the work target can be captured during work using the power tool 1. Specifically, the imaging unit 14 is disposed at the tip of the body 21 so that the tip tool 242 attached to the output shaft 241 falls within the imaging range. The captured image captured by the imaging unit 14 may be used for various judgments when the control unit 12 performs control, or may be sent to an external processing device by wireless communication and used for various judgments by the processing device. The power tool 1 does not have to include the imaging unit 14.

[0032] The mounting unit 23 is provided with a light-emitting unit 234 for photographing. The light-emitting unit 234 includes, for example, an LED. The light-emitting unit 234 irradiates light toward a work target when working with the power tool 1. The light-emitting unit 234 can be turned on / off, for example, by operating the operation panel 231. By providing the light-emitting unit 234 in the power tool 1, the amount of light received by the imaging unit 14 can be increased.

[0033] The gas detection unit 15 detects a combustible gas. The gas detection unit 15 is, for example, a gas sensor that detects a combustible gas. Gases that the gas detection unit 15 can detect include, for example, natural gas or propane gas, and more specifically, for example, methane or propane. The gas sensor is, for example, a semiconductor type or catalytic combustion type gas sensor, but is not limited thereto.

[0034] The gas detection unit 15 is mounted on the power tool 1. As shown in Fig. 2, the gas detection unit 15 is held in a body 20 (body portion 21) of the power tool 1. The gas detection unit 15 is provided, for example, at a position in the body portion 21 near the imaging unit 14. Note that the position at which the gas detection unit 15 is provided is not limited thereto, and the gas detection unit 15 may be provided, for example, at any position in the body portion 21 (for example, near the notification unit 16).

[0035] The notification unit 16 notifies the outside that a flammable gas has been detected by the gas detection unit 15. The notification unit 16 includes, for example, an LED. The notification unit 16 is provided, for example, at the end of the trunk portion 21 of the body 20 opposite the output shaft 241 so that the user can easily see the notification unit 16 while working (see FIG. 3).

[0036] In the power tool 1 of this embodiment, the control unit 12 has, as operation modes, a normal mode and a gas leakage mode.

[0037] The control unit 12 mainly comprises, for example, a microcontroller having one or more processors and one or more memories. The microcontroller realizes the function of the control unit 12 by executing a program recorded in one or more memories with one or more processors. The program may be recorded in the memory in advance, or may be provided by recording it on a non-transitory recording medium such as a memory card, or may be provided through an electric communication line. In other words, the program is a program for causing one or more processors to function as the control unit 12.

[0038] As shown in FIG. 1, the control unit 12 has the functions of a drive control unit 121, a gas leakage determination unit 122, a mode switching unit 123, a notification control unit 124, and the like.

[0039] The drive control unit 121 controls the operation of the drive unit 11. That is, the drive control unit 121 controls the rotation operation of the motor 111. Specifically, in the normal mode, the drive control unit 121 rotates the motor 111 so as to rotate the output shaft 241 at a rotation speed based on the retracted amount of the trigger switch 221 and in a rotation direction set by the forward / reverse changeover switch 222.

[0040] Further, the drive control unit 121 controls the drive unit 11 so that the tightening torque applied to the tightening part becomes the torque setting value. The drive control unit 121 has a torque estimation function for estimating the magnitude of the tightening torque. In the present embodiment, as an example, the drive control unit 121 estimates the magnitude of the tightening torque based on the rotation speed of the motor 111 and the like until the estimated value of the tightening torque reaches the seating determination level. When the estimated value of the tightening torque reaches the seating determination level, the drive control unit 121 estimates the magnitude of the tightening torque based on the number of strikes of the impact mechanism 131. When the number of strikes of the impact mechanism 131 reaches a threshold number of times according to the torque setting value, the drive control unit 121 determines that the tightening torque has reached the torque setting value and stops the motor 111. This allows the power tool 1 to tighten the tightening part with the tightening torque according to the torque setting value. Note that the torque estimation function of the drive control unit 121 is not limited to this. For example, an estimate of the fastening torque may be obtained using a torque sensor, or an estimate of the fastening torque may be obtained based on the value of the current flowing through the motor 111.

[0041] The gas leakage determination unit 122 determines whether or not there is a leakage of flammable gas based on the detection result of the gas detection unit 15. For example, the gas leakage determination unit 122 determines whether or not the concentration of the flammable gas is equal to or higher than a predetermined determination threshold. For example, when the gas leakage determination unit 122 detects that the concentration of the flammable gas is equal to or higher than the determination threshold, the gas leakage determination unit 122 determines that "flammable gas has been detected." The determination threshold may be determined based on, for example, a lower explosion limit (LEL). The determination threshold may be, for example, a value that is approximately 1 / 10 of the lower explosion limit. The function of the gas leakage determination unit 122 may be possessed by the gas detection unit 15.

[0042] As described above, the control unit 12 has, as operation modes, the normal mode and the gas leakage mode.

[0043] The gas leakage mode is a mode for preventing malfunctions of the power tool 1 caused by flammable gas. In this embodiment, the gas leakage mode is started in response to the detection of flammable gas by the gas detection unit 15 (more specifically, the determination by the gas leakage determination unit 122 that "flammable gas has been detected"). When flammable gas is detected by the gas detection unit 15, the gas leakage mode is automatically started regardless of the operation of the power tool 1 by the user. Note that, in this embodiment, the normal mode is the operating mode of the control unit 12 in cases other than the gas leakage mode.

[0044] In the gas leakage mode, the control unit 12 performs control differently from that in the normal mode. In the gas leakage mode, the control unit 12 restricts the operation of the power tool 1 more than in the normal mode.

[0045] In this embodiment, the control unit 12 imposes a restriction on the rotation direction of the output shaft 241 in the gas leakage mode. Specifically, in the gas leakage mode, the control unit 12 permits forward rotation, which rotates the output shaft 241 in a direction for tightening the fastening parts, and prohibits reverse rotation, which rotates the output shaft 241 in a direction for loosening the fastening parts. For example, in the gas leakage mode, when the forward / reverse changeover switch 222 sets the rotation direction of the output shaft 241 to forward rotation, the control unit 12 rotates the motor 111 when the trigger switch 221 is turned on. On the other hand, in the gas leakage mode, when the forward / reverse changeover switch 222 sets the rotation direction of the output shaft 241 to reverse rotation, the control unit 12 does not rotate the motor 111 even if the trigger switch 221 is turned on.

[0046] Here, the leakage of flammable gas may occur, for example, when removing an existing gas pipe through which flammable gas flows, because the valve of the gas pipe preceding the gas pipe to be removed is forgotten to be closed. In other words, if the fastening parts connecting the flanges of the gas pipes are loosened while the valve of the preceding gas pipe is forgotten to be closed, gas may leak from the gap between the flanges that is created by loosening the fastening parts.

[0047] Therefore, in the power tool 1 of the present embodiment, when flammable gas is detected, rotation in a direction that would loosen the fastening parts (reverse rotation of the output shaft 241) is prohibited. This prevents the user from further loosening the fastening parts, which would lead to the spread of flammable gas leakage.

[0048] On the other hand, in the power tool 1 of this embodiment, even if flammable gas is detected, rotation in the direction for tightening the fastening parts (forward rotation of the output shaft 241) is permitted. Therefore, the user can use the power tool 1 to tighten the fastening parts. This allows the user to use the power tool 1 to retighten the fastening parts and close the gap that has occurred between the flanges. This makes it possible to prevent the leakage of flammable gas from spreading.

[0049] In the power tool 1 of this embodiment, the control unit 12 sets the upper limit of the rotation speed of the motor 111 during forward rotation in the gas leakage mode to be lower than the upper limit of the rotation speed of the motor 111 during forward rotation in the normal mode. This makes it less likely for sparks to be generated in the motor 111, for example, thereby reducing the possibility of a malfunction of the power tool 1 due to flammable gas.

[0050] The control unit 12 may set the upper limit of the rotation speed of the motor 111 during forward rotation in the gas leakage mode to a predetermined value, thereby making the upper limit lower than the upper limit of the rotation speed of the motor 111 during forward rotation in the normal mode. For example, the control unit 12 may set the upper limit of the rotation speed of the motor 111 during forward rotation in the gas leakage mode to a minimum rotation speed required for fastening the fastening parts. The upper limit of the rotation speed of the motor 111 in the gas leakage mode may be set by the user depending on the type of fastening part used (bolt or nut, size, etc.).

[0051] The control unit 12 may set the upper limit of the rotation speed of the motor 111 during forward rotation in the gas leak mode based on the upper limit of the rotation speed of the motor 111 during forward rotation in the normal mode (e.g., to half, ⅓, etc.). For example, the control unit may set the upper limit of the rotation speed of the motor 111 during forward rotation in the gas leak mode based on the upper limit (for the normal mode) set using the operation panel 231.

[0052] The mode switching unit 123 switches the operation mode of the control unit 12. When a switching condition is satisfied, the mode switching unit 123 switches the operation mode of the control unit 12 from the normal mode to the gas leakage mode.

[0053] The switching condition includes, for example, detection of flammable gas by the gas detection unit 15 (more specifically, determination by the gas leakage determination unit 122 that "flammable gas has been detected"). That is, when flammable gas is detected by the gas detection unit 15 during operation in the normal mode, the mode switching unit 123 switches the operation mode of the control unit 12 from the normal mode to the gas leakage mode.

[0054] Furthermore, when the release condition is satisfied, the mode switching unit 123 switches the operation mode of the control unit 12 from the gas leakage mode to the normal mode.

[0055] The release condition includes, for example, that the concentration of the flammable gas detected by the gas detection unit 15 falls below the judgment threshold and a predetermined switch (for example, any of the multiple push button switches 232) provided on the power tool 1 is operated. That is, when the concentration of the flammable gas detected by the gas detection unit 15 falls below the judgment threshold and the predetermined switch is operated during operation in the gas leakage mode, the mode switching unit 123 switches the operation mode of the control unit 12 from the gas leakage mode to the normal mode.

[0056] The control unit 12 may start operation in the gas leakage mode based on the detection result of the gas detection unit 15 even if the trigger switch 221 is not operated. Furthermore, the control unit 12 may resume operation in the gas leakage mode when the power tool 1 is turned off during operation in the gas leakage mode and then turned on again.

[0057] The notification control unit 124 controls the notification unit 16. When the gas detection unit 15 detects flammable gas (more specifically, when the gas leakage determination unit 122 determines that "flammable gas has been detected"), the notification control unit 124 controls the notification unit 16 to notify that a gas leak has occurred. When the gas detection unit 15 detects flammable gas, the notification control unit 124 may turn on or blink the LED of the notification unit 16.

[0058] By providing the notification unit 16, the user of the power tool 1 can easily know that the operation mode of the control unit 12 has switched from the normal mode to the gas leakage mode. Therefore, even if the rotation of the motor 111 suddenly stops because the operation mode has switched to the gas leakage mode, the user can easily know the cause (generation of flammable gas) and is less likely to mistake it for, for example, a malfunction of the power tool 1. In addition, the user can easily know that flammable gas has been detected by the gas detection unit 15. In other words, user convenience can be improved.

[0059] As described above, the power tool 1 of this embodiment includes the gas detection unit 15. This makes it possible to reduce the possibility of malfunction of the power tool 1 due to flammable gas. In addition, since the power tool 1 itself includes the gas detection unit 15 and automatically starts the gas leakage mode when it detects flammable gas, the system configuration is simplified and the usability of the power tool 1 is improved compared to a configuration in which an external device of the power tool 1 includes the gas detection unit and instructs the power tool 1 to start the gas leakage mode. In short, the power tool 1 of this embodiment makes it possible to improve the convenience for the user.

[0060] (2) Variations The above embodiment is merely one of various embodiments of the present disclosure. The above embodiment can be modified in various ways depending on the design, etc., as long as the object of the present disclosure can be achieved. In addition, the same function as the control unit 12 according to the above embodiment may be embodied in a control method, a computer program, or a non-transitory recording medium having a computer program recorded thereon.

[0061] Specifically, a control method according to one embodiment is executed by the control unit 12 of the power tool 1 including a motor 111, a control unit 12 that controls the rotation operation of the motor 111, and a gas detection unit 15 that detects flammable gas. As shown in Fig. 4, the control method includes determining whether or not flammable gas is detected by the gas detection unit 15 (ST1). The control method includes operating in a normal mode (ST2) when flammable gas is not detected by the gas detection unit 15 (ST1: No). The control method includes starting a gas leakage mode that performs control different from the normal mode (ST3) when flammable gas is detected by the gas detection unit 15 (ST1: Yes).

[0062] A program according to one aspect is a program for causing one or more processors to execute the above-described control method. The program may be recorded in, for example, a non-transitory recording medium.

[0063] Modifications of the above embodiment are listed below. The modifications described below can be applied in appropriate combination.

[0064] The control unit 12 in the present disclosure includes a computer system. The computer system is mainly composed of a processor and a memory as hardware. The function of the control unit 12 in the present disclosure is realized by the processor executing a program recorded in the memory of the computer system. The program may be pre-recorded in the memory of the computer system, may be provided through an electric communication line, or may be recorded and provided in a non-transitory recording medium such as a memory card, an optical disk, or a hard disk drive that can be read by the computer system. The processor of the computer system is composed of one or more electronic circuits including a semiconductor integrated circuit (IC) or a large scale integrated circuit (LSI). The integrated circuits such as IC or LSI referred to here are called by different names depending on the degree of integration, and include integrated circuits called system LSI, VLSI (Very Large Scale Integration), or ULSI (Ultra Large Scale Integration). Furthermore, a field-programmable gate array (FPGA) that is programmed after the manufacture of the LSI, or a logic device that can reconfigure the connection relationship inside the LSI or reconfigure the circuit partition inside the LSI, can also be adopted as a processor. The electronic circuits may be integrated in one chip or distributed across multiple chips. The multiple chips may be integrated into one device, or may be distributed across multiple devices. The computer system referred to here includes a microcontroller having one or more processors and one or more memories. Therefore, the microcontroller is also composed of one or more electronic circuits including a semiconductor integrated circuit or a large-scale integrated circuit.

[0065] Moreover, it is not essential that the multiple functions of each of the control units 12 are concentrated in one housing. Each of the components of the control unit 12 may be distributed across multiple housings. Conversely, the multiple functions of each of the control units 12 may be concentrated in one housing. Furthermore, at least some of the functions of each of the control units 12 may be realized by the cloud (cloud computing) or the like.

[0066] (2.1) Variation 1 The power tool 1 of this modification differs from the power tool 1 of the above embodiment in the operation in the gas leakage mode. In the power tool 1 of this modification, the control unit 12 prohibits the motor 111 from rotating in the gas leakage mode.

[0067] That is, in the power tool 1 of this modification, when the gas detection unit 15 detects flammable gas, the control unit 12 does not rotate the motor 111 even if the trigger switch 221 is operated (regardless of forward or reverse rotation).

[0068] This prevents the user from loosening the fastening parts further and causing the leakage of flammable gas to spread when flammable gas is detected when removing an existing gas pipe for passing the flammable gas. In addition, since the occurrence of a situation in which a spark occurs in the motor 111 or the like is prevented, the possibility of a malfunction of the power tool 1 due to flammable gas is reduced.

[0069] The power tool 1 may be switchable between a first mode in which only reverse rotation is prohibited in the gas leakage mode as in the above embodiment, and a second mode in which rotation of the motor 111 is prohibited regardless of the direction of rotation in the gas leakage mode as in this modified example. Switching between the first mode and the second mode may be performed, for example, by operating a predetermined switch (e.g., any one of the multiple push button switches 232) provided on the power tool 1.

[0070] (2.2) Other Modifications In one modified example, the notification unit 16 is not limited to a configuration including an LED. The notification unit 16 may include, for example, a display such as a liquid crystal display, a speaker, a communication unit for communicating with an external processing device (for example, a wireless communication unit for wireless communication), etc. The notification control unit 124 may cause the notification unit 16 to notify the outside that a flammable gas has been detected, for example, by displaying an image on the display, outputting a sound or an artificial voice from the speaker, or transmitting information to the processing device by wireless communication.

[0071] In one modified example, the control unit 12 may be able to set the upper limit of the rotation speed of the motor 111 in a plurality of stages according to the concentration of the flammable gas.

[0072] (3) Description As described above, the power tool (1) of the first aspect includes the motor (111), the control unit (12), and the gas detection unit (15). The control unit (12) controls the rotation of the motor (111). The gas detection unit (15) detects flammable gas. The control unit (12) has two operation modes: a normal mode and a gas leakage mode. The gas leakage mode is started in response to detection of flammable gas by the gas detection unit (15). In the gas leakage mode, the control unit (12) performs control different from that in the normal mode.

[0073] According to this aspect, it is possible to reduce the possibility that a malfunction of the power tool (1) caused by flammable gas is caused, and it is possible to improve convenience for the user.

[0074] The power tool (1) of the second embodiment is the same as that of the first embodiment, and further includes an output shaft (241). A tool tip (242) for tightening or loosening a fastening part is coupled to the output shaft (241). The output shaft (241) rotates in response to the rotation of the motor (111). In the gas leakage mode, the control unit (12) allows forward rotation of the output shaft (241) in a direction for tightening the fastening part. In the gas leakage mode, the control unit (12) prohibits reverse rotation of the output shaft (241) in a direction for loosening the fastening part.

[0075] According to this aspect, when flammable gas is detected, it is possible to prevent the leakage of the flammable gas from spreading.

[0076] In the power tool (1) of the third aspect, in the second aspect, the control unit (12) sets the upper limit of the rotational speed of the motor (111) during forward rotation in the gas leakage mode to be lower than the upper limit of the rotational speed of the motor (111) during forward rotation in the normal mode.

[0077] According to this aspect, it is possible to further reduce the possibility that a malfunction of the power tool (1) due to flammable gases occurs.

[0078] In the electric power tool (1) of the fourth aspect, in any one of the first to third aspects, the control unit (12) inhibits the rotation of the motor (111) in the gas leakage mode.

[0079] According to this aspect, it is possible to further reduce the possibility that a malfunction of the power tool (1) due to flammable gases occurs.

[0080] The power tool (1) of a fifth aspect is the power tool of any one of the first to fourth aspects, further including a notification unit (16). The notification unit (16) notifies an outside device that a flammable gas has been detected by the gas detection unit (15).

[0081] According to this aspect, it is possible to improve convenience for the user. [Explanation of symbols]

[0082] 1 Power tools 111 Motor 12 Control section 15 Gas detection unit 16 Notification Department 241 Output shaft 242 Tip tool

Claims

1. A motor; A control unit for controlling a rotation operation of the motor; A gas detection unit that detects a flammable gas, The control unit has the following operation modes: Normal mode and A gas leakage mode that is started in response to the detection of the flammable gas by the gas detection unit and performs control different from the normal mode. Power tools.

2. The tool further includes an output shaft to which a tool tip for tightening or loosening a fastening part is connected and which rotates in response to the rotation of the motor, In the gas leakage mode, the control unit A forward rotation is permitted to rotate the output shaft in a direction in which the fastening part is fastened, Prohibiting reverse rotation of the output shaft in a direction that loosens the fastening part; The power tool according to claim 1.

3. The control unit sets, in the gas leakage mode, an upper limit value of the rotation speed of the motor during the forward rotation to be lower than an upper limit value of the rotation speed of the motor during the forward rotation in the normal mode. The power tool according to claim 2.

4. The control unit prohibits rotation of the motor in the gas leakage mode. The power tool according to claim 1.

5. The gas detector further includes a notification unit that notifies an outside party that the gas detector has detected the flammable gas. The power tool according to claim 1.

Images