Fastening tool

Abstract

A fastening tool is provided. The fastening tool has a motor, an anvil, a pin holding portion, a magnet, a first magnetic sensor, a second magnetic sensor, and a control device. The magnet is arranged in a manner that an N pole and an S pole are arranged in a front-rear direction, and is moved in the front-rear direction integrally with the pin holding portion. The second magnetic sensor is arranged at a position further to the rear than the first magnetic sensor. The control device moves the pin holding portion from an initial position to a stop position to the rear based on a detection result of the second magnetic sensor, and moves the pin holding portion from the stop position to the initial position to the front based on a detection result of the first magnetic sensor. The first magnetic sensor and the second magnetic sensor are single-pole detection type sensors configured to detect the same prescribed magnetic pole of the magnet, and are arranged such that an orientation of a first detection surface with respect to a movement axis of the magnet is opposite to an orientation of a second detection surface with respect to the movement axis of the magnet. Accordingly, detection accuracy of the first magnetic sensor and the second magnetic sensor can be improved.

Description

Technical Field

[0001] This invention relates to a fastening tool that uses fasteners to secure workpieces. Background Technology

[0002] A fastening tool is known that uses a fastener having a pin and a cylindrical portion to fasten multiple workpieces. For example, in the fastening tool disclosed in Patent Document 1, the pin holding portion (jaw assembly) grips the pin and pulls it axially relative to the cylindrical portion as it moves rearward from an initial position, thereby deforming the fastener and fastening the workpieces. After reaching a predetermined stop position, the pin holding portion returns to the initial position. The movement of the pin holding portion is controlled based on the detection results from two sensors.

[0003] [Existing Technical Documents]

[0004] [Patent Literature]

[0005] Patent Document 1: Japanese Patent Publication No. 2019-892 Summary of the Invention

[0006] [The technical problem that the invention aims to solve]

[0007] In the fastening tool described in Patent Document 1, two Hall effect sensors are used to detect the magnetic field of a magnet that moves integrally with the pin holding part. The detection accuracy of the position detection mechanism utilizing a magnetic sensor such as a Hall effect sensor is affected by the mounting method of the magnetic sensor.

[0008] In view of the above, the object of the present invention is to provide an improvement in a position detection mechanism in a fastening tool that uses a fastener comprising a pin and a cylindrical portion to fasten a workpiece.

[0009] [Technical solutions used to solve technical problems]

[0010] According to one aspect of the present invention, a fastening tool is provided, which is configured to fasten a workpiece using a fastener comprising a pin and a cylindrical portion. The fastening tool includes a motor, an anvil, a pin holder, a magnet, a first magnetic sensor, a second magnetic sensor, and a control device.

[0011] The anvil is configured to abut against the cylindrical portion. The pin holding portion is configured to hold a pin for fastening. The pin holding portion is configured to move relative to the anvil along a first axis powered by a motor. The first axis defines the front-rear direction of the fastening tool. Magnets are arranged with their N and S poles aligned in the front-rear direction. The magnets are configured to move integrally with the pin holding portion along a second axis parallel to the first axis in the front-rear direction. A first magnetic sensor has a first detection surface. A second magnetic sensor has a second detection surface. The second magnetic sensor is positioned rearward than the first magnetic sensor. The control device is configured to move the pin holding portion rearward relative to the anvil from an initial position to a stop position based on the detection result of the second magnetic sensor, and to move the pin holding portion forward relative to the anvil from the stop position to the initial position based on the detection result of the first magnetic sensor.

[0012] The first and second magnetic sensors are unipolar detection type sensors configured to detect the same predetermined magnetic pole of a magnet. In other words, the first and second magnetic sensors are configured to either both react only to the N pole of the magnet (detecting only the magnetic field of the N pole) or both both react only to the S pole of the magnet (detecting only the magnetic field of the S pole). The first and second magnetic sensors are configured such that the orientation of the first detection surface relative to the second axis is opposite to the orientation of the second detection surface relative to the second axis.

[0013] In the fastening tool described in this method, when a magnet approaches the second magnetic sensor from the front and when a magnet approaches the first magnetic sensor from the rear, the magnetic poles of the magnets that first approach each magnetic sensor are different. Conversely, the orientation of the first detection surface of the first magnetic sensor relative to the second axis (the axis of movement of the magnet) is opposite to the orientation of the second detection surface of the second magnetic sensor relative to the second axis. Therefore, either the first or second magnetic sensor can function in the same way as a single-pole detection type sensor used to detect a magnetic pole opposite to its original magnetic pole. Thus, when a magnet approaches the second magnetic sensor from the front and when a magnet approaches the first magnetic sensor from the rear, the change in the magnetic field (magnetic flux density) of the magnetic poles detected by each magnetic sensor is the same. Accordingly, the size design of the fastening tool becomes easier, the possibility of errors is reduced, and therefore the position detection accuracy of the pin holding part is improved.

[0014] According to another aspect of the invention, a fastening tool is provided, which is configured to fasten a workpiece using a fastener comprising a pin and a cylindrical portion. The fastening tool includes a motor, an anvil, a pin holder, a magnet, a first magnetic sensor, a second magnetic sensor, and a control device.

[0015] The anvil is configured to abut against the cylindrical portion. The pin holding portion is configured to hold a pin for fastening. The pin holding portion is configured to move relative to the anvil along a first axis powered by a motor. The first axis defines the front-rear direction of the fastening tool. Magnets are arranged with their N and S poles aligned in the front-rear direction. The magnets are configured to move integrally with the pin holding portion along a second axis parallel to the first axis in the front-rear direction. A first magnetic sensor defines a first detection direction. A second magnetic sensor defines a second detection direction. The second magnetic sensor is positioned rearward than the first magnetic sensor. The control device is configured to move the pin holding portion rearward relative to the anvil from an initial position to a stop position based on the detection result of the second magnetic sensor, and to move the pin holding portion forward relative to the anvil from the stop position to the initial position based on the detection result of the first magnetic sensor.

[0016] The first and second magnetic sensors are unipolar detection type sensors configured to detect the same predetermined magnetic pole of a magnet. In other words, the first and second magnetic sensors are configured to either both react only to the N pole of the magnet (detecting only the magnetic field of the N pole) or both both react only to the S pole of the magnet (detecting only the magnetic field of the S pole). The first and second magnetic sensors are configured such that the orientation of the first detection direction relative to the second axis is opposite to the orientation of the second detection direction relative to the second axis.

[0017] In the fastening tool described in this method, when a magnet approaches the second magnetic sensor from the front and when a magnet approaches the first magnetic sensor from the rear, the magnetic poles of the magnets that first approach each magnetic sensor are different. Conversely, the orientation of the first detection direction of the first magnetic sensor relative to the second axis (the axis of movement of the magnet) is opposite to the orientation of the second detection direction of the second magnetic sensor relative to the second axis. Therefore, either the first or second magnetic sensor can function in the same way as a single-pole detection type sensor used to detect a magnetic pole opposite to its original magnetic pole. Thus, when a magnet approaches the second magnetic sensor from the front and when a magnet approaches the first magnetic sensor from the rear, the change in the magnetic field (magnetic flux density) of the magnetic poles that cause each magnetic sensor to react is the same. Accordingly, the size design of the fastening tool becomes easier, the possibility of errors is reduced, and therefore the position detection accuracy of the pin holding part is improved. Attached Figure Description

[0018] Figure 1 This is an illustration of an example of a fastener that can be used in fastening tools.

[0019] Figure 2 This is a left view of the fastening tool with the auxiliary handle installed.

[0020] Figure 3 This is a cross-sectional view of the fastening tool with the threaded shaft and pin holding part configured in the initial position.

[0021] Figure 4 yes Figure 3 A magnified view of a portion of the image.

[0022] Figure 5 yes Figure 2 A partial cross-sectional view of VV.

[0023] Figure 6 yes Figure 4 Sectional view VI-VI.

[0024] Figure 7 This is the main view of the fastening tool with the auxiliary handle installed.

[0025] Figure 8 It includes Figure 4 A magnified view of the area of ​​the location detection agency.

[0026] Figure 9 This is a schematic diagram used to illustrate the positional relationship between the magnet and the first / second sensor and the change in magnetic flux density.

[0027] Figure 10 This is a partial sectional view of the fastening tool with the threaded shaft and pin holding part positioned in the stop position.

[0028] Figure 11 This is a schematic diagram used to illustrate the positional relationship between the magnet and the first / second sensor in the comparative example, as well as the change in magnetic flux density.

[0029] Figure 12 This is a schematic diagram used to illustrate the positional relationship between the magnet and the first / second sensor and the change in magnetic flux density in the modified example.

[0030] [Explanation of reference numerals in the attached figures]

[0031] 1: Fastening tool; 10: Tool body; 102: Metal housing; 103: Cylindrical part; 104: Support part; 105: Threaded hole; 107: Resin housing; 108: Opening; 109: Eye bolt; 12: Receiving part; 121: Guide plate; 123: Guide groove; 125: Support rib; 13: Extension part; 14: Battery holding part; 141: Battery holder; 145: Battery; 15: Recycling container; 16: Machine head; 161: Anvil; 162: Connecting component; 163: Connecting component; 165: Pin holding part; 166: Connecting component; 17: Handle; 171: Trigger; 172: Switch; 18: Auxiliary handle; 20: Controller; 21: Motor; 213: Motor shaft; 25: LED light; 3: Drive mechanism; 31: Planetary reducer; 32: Drive gear; 33: Idler gear; 40: Ball screw mechanism; 41: Nut; 411: Driven gear; 45: Threaded shaft; 450: Drive shaft; 451: Extension setting shaft; 46: Bearing retainer; 461: Base part; 462: Threaded hole; 463: Arm part; 465: Bearing; 47: Magnet retainer; 471: Through hole; 475: Screw; 48: Magnet; 8: Position detection mechanism; 80: Magnetic sensor; 81: First sensor; 82: Second sensor; 86: First base plate; 87: Second base plate; 9: Fastener; 91: Pin; 95: Collar; 911: Shaft part; 913: Small diameter part; 915: Head; A1: Drive axis; A2: Rotation axis; A3: Movement axis; P: Plane; MS (MS1, MS2): Mounting surface; SD (SD1, SD2): Detection direction; SP (SP1, SP2): Detection point; SS (SS1, SS2): Detection surface; W: Working part. Detailed Implementation

[0032] In one or more embodiments of the present invention, the magnetic pole is defined as the rearmost magnetic pole among the N and S poles. Alternatively, the first detection surface of the first magnetic sensor may be configured facing the second axis, and the second detection surface of the second magnetic sensor may be configured facing away from the second axis. Or, the first detection direction of the first magnetic sensor may be away from the second axis, and the second detection direction of the second magnetic sensor may be towards the second axis. According to this structure, the second magnetic sensor can function similarly to a unipolar detection type sensor for detecting a magnetic pole opposite to the original magnetic pole (one of the N and S poles, the front one). Therefore, the second magnetic sensor can operate as the magnetic flux density of the front magnetic pole increases relatively rapidly after the rear magnetic pole passes through the sensing point of the second magnetic sensor. Furthermore, the first magnetic sensor functions as a unipolar detection type sensor for detecting the original magnetic pole (one of the N and S poles, the rear one), and can operate as the magnetic flux density of the rear magnetic pole increases relatively rapidly after the front magnetic pole passes through the sensing point of the first magnetic sensor. Therefore, the detection accuracy of the first and second magnetic sensors can be improved. Furthermore, it is specified that the magnetic pole can also be an N pole. Based on this structure, a N-pole detection sensor with a larger flux can be effectively utilized.

[0033] In one or more embodiments of the present invention, the first magnetic sensor and the second magnetic sensor may be configured on the same side relative to an imaginary plane containing the second axis. According to this structure, the first magnetic sensor and the second magnetic sensor can be configured within a relatively small space in a direction intersecting the second axis.

[0034] In one or more embodiments of the present invention, the distance between the magnet and the detection point of the first magnetic sensor when the magnet and the first magnetic sensor are located on a first straight line orthogonal to the second axis is equal to the distance between the magnet and the detection point of the second magnetic sensor when the magnet and the second magnetic sensor are located on a second straight line orthogonal to the second axis. According to this structure, when the magnet approaches the second magnetic sensor from the front and when the magnet approaches the first magnetic sensor from the rear, the changes in the magnetic field (magnetic flux density) of the magnetic poles that cause each magnetic sensor to react are more reliably equal.

[0035] In one or more embodiments of the present invention, the first magnetic sensor and the second magnetic sensor may be mounted on separately disposed first and second substrates, respectively. This structure improves the assembly flexibility of the first and second magnetic sensors.

[0036] In one or more embodiments of the present invention, the first magnetic sensor and the second magnetic sensor may be sensors having the same structure. According to this structure, when a magnet approaches the second magnetic sensor from the front and when a magnet approaches the first magnetic sensor from the rear, the changes in the magnetic field (magnetic flux density) of the magnetic poles that cause each magnetic sensor to react are more reliably equal.

[0037] In one or more embodiments of the present invention, the fastening tool may use a fracture fastener as the fastener, in which a pin having a small diameter portion for fracture is inserted into a cylindrical portion. The pin holding portion may be configured such that, during the movement from an initial position to a stop position, the pin is pulled rearward relative to the fastener to fasten the workpiece, and the pin breaks at the small diameter portion. According to this structure, after the load applied to the pin holding portion drops sharply due to the breakage of the pin, the pin holding portion can be appropriately stopped at the stop position.

[0038] Hereinafter, with reference to the accompanying drawings, representative and non-limiting embodiments of the present invention will be specifically described. In the following embodiments, a fastening tool 1 capable of using fasteners to fasten workpieces is illustrated.

[0039] Fastening tool 1 can selectively use a variety of fasteners. Figure 1 The fastener 9 shown is an example of a fastener that can be used to fasten the tool 1. More specifically, the fastener 9 is an example of a known fastener known as a multi-piece swage-type fastener.

[0040] The structure of fastener 9 will now be briefly described. Fastener 9 includes a pin 91 and a collar 95. Pin 91 includes a shaft portion 911 and a head 915 integrally formed with one end of the shaft portion 911. Collar 95 is a cylindrical component that can be inserted through the shaft portion 911. Pin 91 and collar 95 are originally formed separately. By using fastening tool 1 to pull pin 91 axially relative to collar 95, collar 95 is deformed, and the working part W is fastened by the head 915 of pin 91 and collar 95 riveted to the shaft portion 911 of pin 91.

[0041] Furthermore, multi-piece fasteners include the following types: those in which a portion of the pin's shaft (also called the pin tail or mandrel) breaks off and is torn off (hereinafter, also simply referred to as the fracture type), and those in which the pin's shaft remains intact without breaking (hereinafter, also simply referred to as the non-fracture type). Fastener 9 is of the fracture type. Therefore, a small-diameter portion 913 (groove) for breaking is provided on the shaft portion 911 of pin 91.

[0042] The general structure of fastening tool 1 will be described below.

[0043] like Figure 2 and Figure 3 As shown, the fastening tool 1 has a tool body 10, a head 16, and a handle 17.

[0044] The tool body 10, also referred to as the housing, houses the motor 21, drive mechanism 3, etc. A battery 145 can be installed on the tool body 10, and the fastening tool 1 operates using power supplied from the battery 145. The head 16 has an anvil 161 and a pin holding portion 165 disposed within the anvil 161. The anvil 161 is connected to one end of the tool body 10 in a manner extending along a predetermined drive axis A1. The handle 17 is an elongated cylindrical body held by the user. The handle 17 is disposed on the side opposite to the anvil 161 in the extension direction of the drive axis A1, and extends in a direction intersecting (more specifically, approximately orthogonal) to the drive axis A1. The handle 17 has a trigger 171 for pressing (pulling) by the user. In this embodiment, both ends of the handle 17 are connected to the tool body 10, which is approximately shaped like a capital letter C. The tool body 10 and the handle 17 together form a ring-shaped portion (ring) that is approximately shaped like a capital letter D.

[0045] When the user applies fastener 9 (refer to) Figure 1 When the pin 91 engages with the top of the anvil 161 and the trigger 171 is pressed, the motor 21 is driven. Powered by the motor 21, the drive mechanism 3 pulls the pin 91 backward relative to the collar 95 with considerable force, deforming the fastener 9 and thus securing the workpiece W.

[0046] Regarding the orientation of the fastening tool 1, for ease of explanation, the extension direction of the drive axis A1 is defined as the front-back direction of the fastening tool 1. In the front-back direction, the side where the head 16 is disposed is defined as the front side, and the opposite side (the side where the handle 17 is disposed) is defined as the rear side. Furthermore, the direction orthogonal to the drive axis A1 and corresponding to the long axis direction of the handle 17 is defined as the up-down direction. In the up-down direction, the end of the handle 17 closest to the drive axis A1 is defined as the upper side, and the opposite side (the end away from the drive axis A1) is defined as the lower side. Additionally, the direction orthogonal to both the front-back and up-down directions is defined as the left-right direction.

[0047] The detailed structure of fastening tool 1 will be described below.

[0048] First, the detailed structure of the tool body 10 and its internal structure will be explained.

[0049] like Figure 2 and Figure 3As shown, the tool body 10 is generally formed in a C-shape, including a receiving portion 12, an extension portion 13, and a battery holding portion 14. The receiving portion 12 extends along the drive axis A1. The front end of the upper portion of the receiving portion 12 (hereinafter referred to as the cylindrical portion 103) is formed in a cylindrical shape. An auxiliary handle 18 can be mounted around the front end of the cylindrical portion 103. The extension portion 13 extends obliquely downward and rearward from the lower end of the receiving portion 12 in the tool body 10. The battery holding portion 14 extends rearward from the central portion in the vertical direction of the extension portion 13. The battery holding portion 14 is configured to hold the battery 145 in a detachable manner. In this embodiment, the battery 145 is mounted to the battery holding portion 14 via a battery holding member 141 supported on the battery holding portion 14. Alternatively, the battery holding portion 14 may be configured to allow direct installation and removal of the battery 145.

[0050] like Figure 3 As shown, the tool body 10 mainly houses a motor 21, a drive mechanism 3, a position detection mechanism 8, and a controller 20.

[0051] Motor 21 is housed in the lower rear end of housing 12. The rotation axis A2 of motor shaft 213 extends parallel to drive axis A1 (i.e., in the front-to-back direction) below drive axis A1. Furthermore, in this embodiment, motor 21 is a brushless DC motor. Motor shaft 213 is capable of rotating in both the forward and reverse directions. The forward direction corresponds to the direction that moves the threaded shaft 45 and pin holding portion 165 (described later) rearward. The reverse direction corresponds to the direction that moves the threaded shaft 45 and pin holding portion 165 forward. Hereinafter, the drive that rotates motor shaft 213 in the forward direction will be referred to as forward rotation drive. The drive that rotates motor shaft 213 in the reverse direction will be referred to as reverse rotation drive.

[0052] The drive mechanism 3 is configured to move the pin 91 of the fastener 9 relative to the collar 95 in the back-and-forth direction via the power of the motor 21. More specifically, the drive mechanism 3 is configured to move the pin holding portion 165 relative to the anvil 161 connected to the tool body 10 along the drive axis A1, wherein the pin holding portion 165 is configured to hold the pin 91. Figure 4 As shown, the drive mechanism 3 of this embodiment includes a planetary reducer 31, a drive gear 32, an idler gear 33, and a ball screw mechanism 40.

[0053] Planetary reducer 31 is disposed coaxially with motor 21 in the housing 12 on the front side of motor 21. Planetary reducer 31 is configured as a multi-stage planetary reducer. Drive gear 32 is disposed coaxially with planetary reducer 31 on the front side of planetary reducer 31. Planetary reducer 31 is configured to increase the torque input from motor shaft 213 and to rotate drive gear 32. Idler gear 33 is disposed above drive gear 32. Idler gear 33 meshes with drive gear 32 and driven gear 411 of nut 41 (described later).

[0054] The ball screw mechanism 40 is a motion conversion mechanism configured to convert rotary motion into linear motion. The ball screw mechanism 40 is mainly composed of a nut 41 and a threaded shaft 45. In this embodiment, the ball screw mechanism 40 is configured to convert the rotary motion of the nut 41 into the linear motion of the threaded shaft 45, thereby causing the pin holding portion 165 to move linearly. The ball screw mechanism 40 is housed in the upper part of the housing portion 12.

[0055] The nut 41 is supported in a state in which it is substantially immobile relative to the tool body 10 in the front-rear direction but is rotatable about the drive axis A1. The nut 41 is formed into a cylindrical shape and has a driven gear 411 integrally provided on its outer periphery. The nut 41 is supported by two bearings on the front and rear sides of the driven gear 411, which are supported on the tool body 10.

[0056] The threaded shaft 45 engages with the nut 41 in a state where it is substantially non-rotatable relative to the tool body 10 about the drive axis A1 but movable in the back-and-forth direction along the drive axis A1. More specifically, the threaded shaft 45 is configured as an elongated strip that extends into the nut 41 along the drive axis A1. Although detailed drawings are omitted, a helical track is defined by grooves formed on the inner circumferential surface of the nut 41 and the outer circumferential surface of the threaded shaft 45, respectively. A plurality of balls are arranged in a rolling manner within the track. The threaded shaft 45 engages with the nut 41 by these balls. An extension shaft 451 is coaxially connected and fixed to the rear end of the threaded shaft 45, and this extension shaft 451 is integrated with the threaded shaft 45. Hereinafter, the integrated threaded shaft 45 and the extension shaft 451 will be collectively referred to as the drive shaft 450.

[0057] The drive shaft 450 has a through hole extending through the drive shaft 450 along the drive axis A1. A detachable collection container 15 is mounted at the rear end of the tool body 10. The collection container 15 is a container for receiving a portion of the shaft (hereinafter referred to as the pin tail) that has separated from the pin 91 of the fastener 9. The pin tail that has separated from the fastener 9 reaches the collection container 15 through the through hole of the drive shaft 450 and is received in the collection container 15.

[0058] In addition, such as Figures 4-6As shown, a bearing retainer 46 is connected to the rear end of the threaded shaft 45. The bearing retainer 46 has: a base portion 461 disposed around the threaded shaft 45; and two arm portions 463 extending to the left and right from the base portion 461. The base portion 461 is held by the rear surface of a shoulder and the front end face of an extending shaft 451, and is connected and fixed to the threaded shaft 45, wherein the shoulder is provided at the rear end of the threaded shaft 45. Accordingly, the bearing retainer 46 is integrated with the threaded shaft 45 (drive shaft 450). A bearing 465 is mounted at the top end of each arm portion 463. On the other hand, a pair of left and right guide plates 121 are fixed to the tool body 10 (receiving portion 12). A guide groove 123 extending in the front-rear direction is formed on each guide plate 121. The left and right bearings 465 are respectively disposed in the left and right guide grooves 123.

[0059] With this structure, when the nut 41 rotates about the drive axis A1 in response to the drive of the motor 21, the threaded shaft 45 moves linearly in the front-back direction relative to the nut 41 and the tool body 10.

[0060] And, as Figure 4 and Figure 6 As shown, a magnet retainer 47 is connected to the lower end of the bearing retainer 46. The magnet retainer 47 is a retaining member for the magnet 48. The magnet retainer 47 is disposed on the lower side of the bearing retainer 46 and has a through hole 471 extending through the magnet retainer 47 in the vertical direction. A threaded hole 462 extending in the vertical direction is formed at the lower end of the bearing retainer 46 (base portion 461). A screw 475 is fastened from the lower side of the magnet retainer 47 to the threaded hole 462 via the through hole 471 of the magnet retainer 47. Accordingly, the magnet retainer 47 and the magnet 48 are connected and fixed to the bearing retainer 46, and are integrated with the threaded shaft 45 (drive shaft 450) via the bearing retainer 46. Furthermore, in this embodiment, the tightening direction of the screw 475 is orthogonal to the drive axis A1 (the moving direction of the threaded shaft 45). Therefore, compared to the case where the tightening direction of the screw 475 is parallel to the moving direction of the threaded shaft 45, a structure is achieved in which the screw 475 is not easily loosened even if the threaded shaft 45 moves.

[0061] The magnet retainer 47 supports the magnet 48 in such a way that the magnet 48 is exposed downwards. Furthermore, in this embodiment, the magnet 48 is arranged with the N pole at the rear and the S pole at the front. Since the magnet retainer 47 is integrated with the threaded shaft 45, as the threaded shaft 45 moves in the front-rear direction along the drive axis A1, the center of the magnet 48 moves in the front-rear direction along the moving axis A3 (on the moving axis A3), wherein the moving axis A3 is parallel to the drive axis A1.

[0062] Figure 4The position detection mechanism 8 shown is a mechanism that detects the position of the threaded shaft 45 and, consequently, the pin holding portion 165 by detecting the magnetic field of the magnet 48. In this embodiment, the position detection mechanism 8 includes two magnetic sensors 80 (first sensor 81 and second sensor 82) arranged separately in the front-rear direction near the movement axis A3 of the magnet 48. The detection results of the magnetic sensors 80 are used for drive control of the motor 21 (and consequently for movement control of the pin holding portion 165). The structure and configuration of the magnetic sensors 80, and the control based on the detection results of the magnetic sensors 80, will be described in detail later.

[0063] like Figure 3 As shown, the controller 20 is disposed within the extension 13. Although detailed illustrations are omitted, the controller 20 includes control circuitry mounted on a circuit board and drive circuitry for the motor 21, etc. Furthermore, in this embodiment, the control circuitry of the controller 20 is configured as a microcomputer including a CPU, ROM, and RAM, etc. The controller 20 is electrically connected to the magnetic sensor 80 (first sensor 81 and second sensor 82), the LED light 25 (described later), and the switch 172, etc., via wires not shown. The controller 20 controls the operation of the fastening tool 1, including the drive of the motor 21.

[0064] Additionally, an LED light 25 is provided at the opening in the front wall formed at the lower end of the extension 13. The LED light 25 is configured to illuminate the front area of ​​the machine head 16 (i.e., the area where fastening operations are performed by fasteners).

[0065] In addition, such as Figure 3 and Figure 5 As shown, in this embodiment, the tool body 10 is formed of a metal housing 102 and a resin housing 107. The metal housing 102 is formed of metal (e.g., aluminum alloy) and includes the aforementioned cylindrical portion 103 and support portion 104, which supports the drive gear 32, idler gear 33, and nut 41. The resin housing 107 is formed of synthetic resin, connected and fixed to the metal housing 102, and integral with the metal housing 102. The resin housing 107 covers most of the support portion 104 in the metal housing 102.

[0066] like Figure 5 As shown, threaded holes 105 are formed on the left and right sides of the portion of the support 104 of the metal housing 102 used to support the nut 41. Openings 108 are formed on the left and right walls of the resin housing 107, exposing the threaded holes 105 to the outside. Figure 2 and Figure 7 As shown, eye bolts 109 can be tightened in each threaded hole 105. By providing a mounting piece for mounting a shoulder strap (not shown) on the ring of the eye bolt 109, the user of the fastening tool 1 can suspend the fastening tool 1 from the shoulder using the shoulder strap.

[0067] The following is a description of the machine head 16. For example... Figure 3 As shown, the machine head 16 is mainly composed of an anvil 161 and a pin holding part 165. Furthermore, since the structures of the anvil 161 and the pin holding part 165 are known, they will be briefly described below.

[0068] The anvil 161 is cylindrical in shape and has a hole extending along the drive axis A1. The top part of the hole is configured to have a smaller diameter than the other parts, so that it can abut (engage) with the collar 95 of the fastener 9. The anvil 161 is connected to the tool body 10 (cylindrical part 103) via connecting parts 162 and 163.

[0069] The pin holding portion 165 is configured to hold the pin 91 (shaft portion 911) of the fastener 9 and is held so as to be movable relative to the anvil 161 in the front-rear direction along the drive axis A1. More specifically, the pin holding portion 165 is coaxially held within a hole with the anvil 161 and is capable of sliding within the hole. The pin holding portion 165, also referred to as a jaw assembly, has multiple jaws (also referred to as jaws) capable of holding the shaft portion 911 of the pin 91. The pin holding portion 165 is configured such that, as it moves relative to the anvil 161 from an initial position ( Figure 3 As the pin (as shown in the image) moves rearward, the gripping force of the pawl increases. The rear end of the pin holding portion 165 is connected to the front end of the threaded shaft 45 via the connecting member 166. Therefore, the pin holding portion 165 and the threaded shaft 45 move integrally in the front-rear direction. Furthermore, the connecting member 166 has a through hole communicating with the through hole of the drive shaft 450.

[0070] The internal structure of the handle 17 will now be described.

[0071] like Figure 3 As shown, inside the handle 17, adjacent to the rear side of the trigger 171, a switch 172 is housed. The switch 172 is normally in the OFF state, but becomes ON in response to the actuation of the trigger 171. When the switch 172 becomes ON, it outputs a specific signal (ON signal) to the controller 20.

[0072] Below, refer to Figure 8 The structure and configuration details of the magnetic sensor 80 of the position detection mechanism 8 are explained.

[0073] In this embodiment, the two magnetic sensors 80 of the position detection mechanism 8 are identical sensors. Each magnetic sensor 80 is configured to detect the presence or absence of a magnetic field and its strength using the Hall effect (Hall sensor; Hall effect sensor).

[0074] The magnetic sensor 80 in this embodiment is a so-called single-pole detection, single-output Hall sensor that detects only one of the N and S poles. More specifically, the magnetic sensor 80 is configured to react only to the N pole of the magnet 48 (detecting the magnetic field of the N pole) and detect the magnetic field component in a direction perpendicular to the detection surface (main surface, reference surface) SS and from the detection surface SS toward the mounting surface MS (detection direction (reference direction) SD). Furthermore, the magnetic sensor 80 performs an ON / OFF operation (switching the output signal between a low signal and a high signal) based on the magnitude of the magnetic field (magnetic flux density) passing through the detection point SP of the magnetic sensor 80 and penetrating the magnetic sensor 80 in the detection direction SD. Specifically, the magnetic sensor 80 is ON (outputting a low signal) when the magnetic flux density exceeds a predetermined threshold and OFF (outputting a high signal) when the magnetic flux density is below the threshold. In addition, the threshold for OFF the magnetic sensor 80 may be different from the threshold for ON the magnetic sensor 80.

[0075] Two magnetic sensors 80 are located on the same side relative to an imaginary plane containing the movement axis A3 of the magnet 48, and are arranged separately in the front-rear direction. More specifically, each magnetic sensor 80 is arranged below an imaginary plane P, which contains the movement axis A3 of the magnet 48 and extends orthogonally to the vertical direction. Accordingly, the two magnetic sensors 80 can be arranged in a compact space in the vertical direction using the empty space in the receiving portion 12 below the threaded shaft 45. Furthermore, each detection point SP of the magnetic sensor 80 is located on a straight line L, which extends parallel to the movement axis A3 (in the front-rear direction) directly below the movement axis A3.

[0076] Furthermore, in the following text, when collectively referring to both magnetic sensors 80, or when referring to either one without distinction, the term "magnetic sensor 80" will be used interchangeably. When referring to both magnetic sensors 80, the front magnetic sensor 80 will be called the first sensor 81, and the rear magnetic sensor 80 will be called the second sensor 82. Additionally, the detection surface SS, mounting surface MS, detection point SP, and detection direction SD of the first sensor 81 will be referred to as detection surface SS1, mounting surface MS1, detection point SP1, and detection direction SD1, respectively. Similarly, the detection surface SS, mounting surface MS, detection point SP, and detection direction SD of the second sensor 82 will be referred to as detection surface SS2, mounting surface MS2, detection point SP2, and detection direction SD2, respectively.

[0077] The first sensor 81 and the second sensor 82 are respectively mounted on different first substrates 86 and second substrates 87 and are supported inside the tool body 10 (receiving portion 12). More specifically, the first substrate 86 and the second substrate 87 are supported by support ribs 125 that protrude from the side wall portion of the tool body 10 (receiving portion 12) toward the inside of the tool body 10.

[0078] Furthermore, the first substrate 86 and the second substrate 87 are configured such that the orientation of the detection surface SS1 (detection direction SD1) of the first sensor 81 relative to the movement axis A3 of the magnet 48 is opposite to the orientation of the detection surface SS2 (detection direction SD2) of the second sensor 82 relative to the movement axis A3. Additionally, in this embodiment, the detection surface SS1 of the front-side first sensor 81 and the detection surface SS2 of the rear-side second sensor 82 are configured parallel to each other and oriented in opposite directions. That is, the detection direction SD1 of the first sensor 81 and the detection direction SD2 of the second sensor 82 are opposite to each other and both are approximately orthogonal to the movement axis A3.

[0079] More specifically, the first substrate 86 is configured such that the detection surface SS1 of the first sensor 81 faces upward (i.e., facing the movement axis A3 and the magnet 48 in the vertical direction). The detection direction SD1 of the first sensor 81 is downward (away from the movement axis A3). This orientation of the first sensor 81 is the same orientation that the magnetic sensor 80, which only reacts to the N pole, would normally have when in use.

[0080] On the other hand, the second substrate 87 is configured such that the detection surface SS2 of the second sensor 82 faces downward (i.e., in the vertical direction, towards a direction away from the moving axis A3 and the magnet 48). The detection direction SD2 of the second sensor 82 is upward (towards the moving axis A3). That is, the second sensor 82 is configured to face a direction opposite to its intended use (i.e., so that the mounting surface MS2 faces the moving axis A3 and the magnet 48). With this configuration, the second sensor 82 functions equivalently to a unipolar detection type Hall sensor that only reacts to the S pole of the magnet facing the mounting surface MS2 (detecting the magnetic field of the S pole).

[0081] In addition, such as Figure 9As shown, the distance (gap) G1 between magnet 48 and detection point SP1 when magnet 48 and first sensor 81 are arranged in a straight line in the vertical direction is equal to the distance (gap) G2 between magnet 48 and detection point SP2 when magnet 48 and second sensor 82 are arranged in a straight line in the vertical direction. In this embodiment, since the first substrate 86 and the second substrate 87 are different substrates, the degree of freedom in mounting relative to the tool body 10 is high. Therefore, it is easy to configure the first substrate 86 and the second substrate 87 in a way that makes the distances G1 and G2 equal.

[0082] When the magnet 48, which moves integrally with the threaded shaft 45 and the pin holding part 165, is positioned at a predetermined position relative to the first sensor 81 and the second sensor 82 as described above, the first sensor 81 and the second sensor 82 are respectively turned on. The output signals from the first sensor 81 and the second sensor 82 are transmitted to the controller 20 via wires not shown.

[0083] The operation of the fastening tool 1 during the operation of fastening the workpiece W using the fastener 9 (hereinafter referred to as the fastening operation) will be described below. During the fastening operation, the threaded shaft 45 and the pin holding part 165 perform a cyclic operation consisting of a forward stroke and a return stroke, wherein the forward stroke is from... Figure 3 The initial position shown moves backward. Figure 10 The travel distance up to the stop position shown is the distance traveled from the stop position to the initial position.

[0084] like Figure 3 As shown, in the initial state where the trigger 171 is not engaged, the threaded shaft 45 (drive shaft 450) and the pin holding part 165 are positioned in their initial positions. The user places the fastener 9 (refer to...) Figure 1 The pin 91 is temporarily fixed to the workpiece W, and the shaft portion 911 of the pin 91 is inserted into the top end (pawl) of the pin holding portion 165, so that it loosely holds the pin 91. When the user pulls the operation trigger 171, the controller 20 (control circuit) responds to the on signal from the switch 172 to energize the motor 21, starting the forward rotation drive of the motor 21. Accordingly, the forward stroke begins.

[0085] The forward rotation of the motor shaft 213 is transmitted to the nut 41 via the planetary reducer 31, drive gear 32, and idler gear 33. As the nut 41 rotates, the threaded shaft 45 and the pin holding part 165 move rearward relative to the tool body 10 and the anvil 161. The shaft portion 911 of the pin 91 is firmly held by the pin holding part 165 and pulled rearward relative to the collar 95 and the working piece W.

[0086] The collar 95 deforms and is riveted to the shaft portion 911 of the pin 91. After the working part W is clamped by the head 915 of the pin 91 and the collar 95, the shaft portion 911 breaks at the small diameter portion 913, the pin tail is separated, and the fastening of the working part W is completed. Figure 10 As shown, in response to the threaded shaft 45 and the pin holding part 165 reaching the predetermined stop position, the controller 20 stops the forward rotation drive of the motor 21.

[0087] In this embodiment, the controller 20 is configured to determine whether the threaded shaft 45 and the pin holding part 165 have reached the stop position based on the detection result of the second sensor 82. More specifically, when the magnet 48 approaches the second sensor 82 from the front and activates the second sensor 82 (when a low signal is detected from the second sensor 82), the controller 20 determines that the threaded shaft 45 and the pin holding part 165 have reached the stop position, and thus brakes the motor 21 to stop it. Accordingly, the forward stroke ends.

[0088] When the user releases the pressure on trigger 171, switch 172 is opened, and in response, controller 20 starts the reverse drive of motor 21. Accordingly, the return stroke begins.

[0089] As the motor shaft 213 rotates in the opposite direction, the nut 41 rotates in the opposite direction to the forward stroke. Accordingly, the threaded shaft 45 and the pin holding part 165 move forward relative to the tool body 10 and the anvil 161. Figure 3 As shown, in response to the threaded shaft 45 and the pin holding part 165 reaching the initial position, the controller 20 stops the reverse drive of the motor 21.

[0090] In this embodiment, the controller 20 is configured to determine whether the threaded shaft 45 and the pin holding part 165 have reached their initial positions based on the detection result of the first sensor 81. More specifically, when the magnet 48 approaches the first sensor 81 from the rear and the first sensor 81 is activated (when a low signal is detected from the first sensor 81), the controller 20 determines that the threaded shaft 45 and the pin holding part 165 have reached their initial positions and brakes the motor 21 to stop it. Accordingly, the return stroke ends, and the fastening operation also ends.

[0091] In this embodiment, through the structure and configuration of the magnet 48 and the two magnetic sensors 80 described above, the correspondence between the change in distance between each magnetic sensor 80 and the magnet 48 and the change in the orientation and magnitude of the magnetic field (magnetic flux density) relative to the detection direction SD is substantially the same during both the forward and return strokes. This will be explained in detail below.

[0092] In this embodiment, the detection object of the first sensor 81 and the second sensor 82 is a single magnet 48. The N pole and S pole of the magnet 48 are arranged in the direction of movement (front-back direction), with the N pole located at the rear and the S pole at the front. Therefore, during the forward stroke, the N pole face of the magnet 48 approaches the second sensor 82 before the S pole face. On the other hand, during the return stroke, the S pole face of the magnet 48 approaches the first sensor 81 before the N pole face.

[0093] Therefore, the relationship between the distance between the first sensor 81 and the magnet 48 during the forward stroke and the magnetic flux density, and the relationship between the distance between the second sensor 82 and the magnet 48 during the return stroke and the magnetic flux density are specifically as follows: Figure 9 As shown. Furthermore, Figure 9 The distance (horizontal axis) in each curve represents the distance between the detection point SP of each magnetic sensor 80 and the center of the magnet 48 (the boundary between the N and S poles) in the direction of movement (forward and backward) of the magnet 48. Furthermore, regarding the magnetic flux density (vertical axis) in each curve, the upper and lower regions correspond to the magnetic fields passing through each detection point SP along the detection direction SD and passing through each magnetic sensor 80 in the opposite direction to the detection direction SD, respectively. Therefore, it can be said that the upper region of the curve for the first sensor 81 corresponds to the magnetic field of the N pole, and the lower region corresponds to the magnetic field of the S pole; similarly, the upper region of the curve for the second sensor 82 corresponds to the magnetic field of the S pole, and the lower region corresponds to the magnetic field of the N pole.

[0094] like Figure 9 As shown, for either the first sensor 81 or the second sensor 82, the relationship between distance and magnetic flux density is represented by an S-shaped curve. As described above, the first sensor 81 and the second sensor 82 are identical Hall sensors configured with detection directions SD1 and SD2 opposite to each other, and the distances G1 and G2 between each detection point SP and the magnet 48 are the same. Therefore, regarding the movement of the magnet 48 in the front-back direction, the curves of the first sensor 81 and the second sensor 82 have the same shape but facing opposite directions.

[0095] More specifically, during the forward travel of the second sensor 82, from the point where the center of the magnet 48 reaches directly above the detection point SP2 of the second sensor 82, the magnetic flux density (N pole) in the opposite direction to the detection direction SD2 gradually increases and then decreases more rapidly. After the center (N pole) of the magnet 48 passes the detection point SP2, the magnetic flux density (S pole) in the detection direction SD2 increases rapidly and then gradually decreases. Since the second sensor 82 functions identically to an S pole detection type Hall sensor, it is activated when the magnetic flux density at the S pole exceeds a threshold during its rapid increase. At this time, the center of the magnet 48 is located at a distance D2 from the detection point SP2 of the second sensor 82.

[0096] On the other hand, during the return stroke, from the point where the center of the magnet 48 reaches directly above the detection point SP1 of the first sensor 81, the magnetic flux density (S pole) in the opposite direction to the detection direction SD1 gradually increases and then decreases more rapidly. After the center (S pole) of the magnet 48 passes the detection point SP1 forward, the magnetic flux density (N pole) in the detection direction SD1 increases rapidly and then gradually decreases. When the magnetic flux density of the N pole exceeds a threshold during its rapid increase, the N pole detection type Hall sensor, i.e., the first sensor 81, is activated. At this time, the center of the magnet 48 is located at a distance D1 forward from the detection point SP1 of the first sensor 81.

[0097] Due to the relationship between the curves of the first sensor 81 and the second sensor 82, distance D1 equals distance D2. That is, the first sensor 81 and the second sensor 82 are switched on at the moment when they pass the same distance from each detection point SP1 and detection point SP2 at the center of the magnet 48. In other words, the positional relationship between the first sensor 81 and the magnet 48 when the first sensor 81 is working is substantially the same as the positional relationship between the second sensor 82 and the magnet 48 when the second sensor 82 is working.

[0098] Here, refer to Figure 11 The comparative examples related to the configuration of the first sensor 81 and the second sensor 82 are explained. For example... Figure 11 As shown, in this comparative example, the first sensor 81 and the second sensor 82 are configured such that the detection directions SD1 and SD2 are both the original orientation (downward), and the distances G1 and G3 between each detection point SP and the magnet 48 are the same. Thus, in this comparative example, only the configuration of the second sensor 82 is different compared to the implementation method.

[0099] In this comparative example, the curves of the first sensor 81 and the second sensor 82 have the same shape and orientation with respect to the movement of the magnet 48 in the forward and backward directions. Specifically, during the forward stroke of the second sensor 82, from the point where the center of the magnet 48 reaches directly above the detection point SP2 of the second sensor 82, the magnetic flux density in the detection direction SD2 (N pole) gradually increases and then decreases more rapidly. After the center (N pole) of the magnet 48 passes the detection point SP2 backward, the magnetic flux density in the opposite direction to the detection direction SD2 (S pole) increases rapidly and then gradually decreases. When the magnetic flux density of the N pole exceeds a threshold during its gradual increase, the N pole detection type Hall sensor, i.e., the second sensor 82, is activated. At this time, the center of the magnet 48 has not reached the detection point SP2 of the second sensor 82, but is located at a distance D3 forward from the detection point SP2. Distance D3 is greater than distance D1.

[0100] Thus, in this comparative example, the positional relationship between the first sensor 81 and the magnet 48 when the first sensor 81 is operating differs from the positional relationship between the second sensor 82 and the magnet 48 when the second sensor 82 is operating. Therefore, taking this difference into account, the dimensional design of various structural elements is required.

[0101] In contrast, as described above, the structure and configuration of the first sensor 81 and the second sensor 82 according to this embodiment make dimensional design easier and reduce the possibility of errors. As a result, compared with the comparative example described above, the position detection accuracy is improved, enabling the threaded shaft 45 and the pin holding portion 165 to be properly stopped in the stop position or the initial position. In the fastening tool 1 using the fracture fastener 9, when the pin 91 breaks between the initial position and the stop position, since the motor 21 rotates at high speed, it is preferable to stop the motor 21 immediately at the stop position. In addition, in order for the pin holding portion 165 to hold the pin 91 with an appropriate holding force in the initial position, it is necessary to stop the pin holding portion 165 with high precision in the initial position. Therefore, in the fastening tool 1 using the fracture fastener 9, improving the position detection accuracy is useful.

[0102] Furthermore, in this embodiment, as described above, for minute distance changes, the first sensor 81 and the second sensor 82 operate when the magnetic flux density of their respective detectable magnetic poles increases relatively rapidly (the slope of the magnetic flux density curve is relatively large), and the magnetic flux density exceeds a threshold. Therefore, compared to the case where they operate during a slow increase in magnetic flux density, the position detection accuracy of the first sensor 81 and the second sensor 82 can be improved.

[0103] The correspondence between the structures (features) of the above embodiments and the structures (features) of the present invention is shown below. However, the structures (features) of the embodiments are merely examples and do not limit the present invention or its structures (features).

[0104] Fastening tool 1 is an example of a "fastening tool". Fastener 9, pin 91, and collar 95 are examples of "fastener", "pin", and "cylindrical part", respectively. Motor 21 is an example of a "motor". Anvil 161 and pin holding part 165 are examples of "anvil" and "pin holding part", respectively. Magnet 48 is an example of a "magnet". First sensor 81 and second sensor 82 are examples of "first magnetic sensor" and "second magnetic sensor", respectively. Controller 20 (more specifically, control circuit) is an example of a "control device". Detection surfaces SS1 and SS2 are examples of "first detection surface" and "second detection surface", respectively. Detection directions SD1 and SD2 are examples of "first detection direction" and "second detection direction", respectively. Detection points SP (SP1, SP2) are examples of "detection points". First substrate 86 and second substrate 87 are examples of "first substrate" and "second substrate", respectively.

[0105] Furthermore, the above embodiments are merely illustrative, and the fastening tool involved in the present invention is not limited to the fastening tool 1 exemplified in the above embodiments. For example, non-limiting modifications as illustrated below can be added. In addition, at least one of these modifications can be combined with at least a portion of the structure (feature) of the fastening tool 1 and at least one of the structures (features) described in the technical solution.

[0106] First, a modified example of the position detection mechanism 8 (first sensor 81 and second sensor 82) and the magnet 48 will be described.

[0107] For example, the first sensor 81 and the second sensor 82 may also be magnetic sensors of a different type than those described in the above embodiments. For example, the first sensor 81 and the second sensor 82 may each be a unipolar detection type Hall sensor that detects the S pole. Furthermore, in this case, from the viewpoint of position detection accuracy, it is preferable to arrange the magnet 48 with the S pole on the rear side and the N pole on the front side. In addition, it is preferable that the first sensor 81 and the second sensor 82 have the same structure (are the same sensors), but if they are unipolar detection type magnetic sensors that detect the same magnetic pole, they do not necessarily need to have the same structure.

[0108] As long as the orientation of the detection surface SS1 (detection direction SD1) relative to the movement axis A3 of the magnet 48 is opposite to the orientation of the detection surface SS2 (detection direction SD2) relative to the movement axis A3 of the magnet 48, the first sensor 81 and the second sensor 82 may not be configured below the movement axis A3 of the magnet 48, but may be configured at other positions. For example, both the first sensor 81 and the second sensor 82 may be configured above, to the right, or to the left of the movement axis A3.

[0109] Alternatively, the first sensor 81 and the second sensor 82 may not be configured on the same side of the plane containing the movement axis A3 of the magnet 48 (not limited to the plane P illustrated in the embodiment), but rather on opposite sides of that plane. For example, as Figure 12 As shown in the variation, the first sensor 81 and the second sensor 82 can also be arranged on the left and right sides respectively relative to the plane P', which includes the movement axis A3 and is orthogonal to the left-right direction (extending in the up-down direction). The distance G1 between the magnet 48 and the detection point SP1 is equal to the distance G2 between the magnet 48 and the detection point SP2. The orientation of the detection surface SS1 of the first sensor 81 is towards the movement axis A3 (the detection direction SD1 is away from the movement axis A3 (to the left)). The orientation of the detection surface SS2 of the second sensor 82 is opposite to that of the first sensor 81, away from the movement axis A3 (the detection direction SD2 is towards the movement axis A3 (to the left)). According to this variation, similar to the above embodiment, the correspondence between the change in distance between each magnetic sensor 80 and the magnet 48, and the change in the orientation and magnitude of the magnetic field (magnetic flux density) relative to the detection direction SD, can be substantially the same in both the forward and return strokes.

[0110] Furthermore, the first sensor 81 and the second sensor 82 do not need to have their detection surfaces SS1 (detection direction SD1) and SS2 (detection direction SD2) parallel and opposite to each other; they can be configured in directions that make them intersect. Although the illustration is omitted, for example, one of the first sensor 81 and the second sensor 82 can be configured below or above the moving axis A3 with its detection direction SD aligned with the vertical direction. The other sensor can also be configured to the left or right of the moving axis A3 with its detection direction SD aligned with the horizontal direction.

[0111] The first sensor 81 and the second sensor 82 do not necessarily need to be configured such that their respective detection surfaces SS1 and SS2 are parallel to the moving axis A3 of the magnet 48 (the detection directions SD1 and SD2 are orthogonal to the moving axis A3). That is, as long as the magnetic field components orthogonal to the detection surfaces SS1 and SS2 (the magnetic field components parallel to the detection directions SD1 and SD2) can be properly detected, the detection surfaces SS1 and SS2 (the detection directions SD1 and SD2) can also be tilted relative to the moving axis A3.

[0112] The first sensor 81 and the second sensor 82 can be mounted on a single substrate. For example, when the first sensor 81 and the second sensor 82 are mounted on a flexible substrate, it is easier to make the aforementioned distances G1 and G2 the same.

[0113] As long as the magnet 48 can move along the front-to-back direction relative to the anvil 161 as an integral part of the pin holding part 165, its placement position or connection method with the pin holding part 165 can be appropriately changed. That is, the magnet 48 can be fixed to the pin holding part 165 or any component directly or indirectly connected to the pin holding part 165 so that it can move integrally with the pin holding part 165.

[0114] The following will explain other variations.

[0115] The fastening tool 1 can also be configured to use fasteners of a different type than the fasteners 9 illustrated in the above embodiments (e.g., blind rivets, shaft-retaining fasteners in multi-piece fastener sets) to fasten the workpiece W. The fastening tool 1 can also accommodate a variety of fasteners by changing the anvil 161 and the pin holder 165. The shape, structural elements, and connection methods of the tool body 10, the head 16, and the handle 17 can be arbitrarily changed.

[0116] Motor 21 can also be a motor other than a brushless DC motor (a DC motor with brushes, an AC motor). The fastening tool 1 can also be configured to operate by power supplied from an external AC power source instead of a battery 145.

[0117] The drive mechanism 3 only needs to be able to move the pin holding part 165 relative to the anvil 161 in the back-and-forth direction by being driven by the power of the motor 21, and its structural elements and configuration can be arbitrarily changed. For example, a feed screw mechanism with a nut and a threaded shaft that directly engage with each other can be used instead of the ball screw mechanism 40. Alternatively, the ball screw mechanism 40 can be configured such that the threaded shaft 45 is supported in a manner that is substantially unable to move in the back-and-forth direction but is rotatable, while the nut 41 moves in the back-and-forth direction as the threaded shaft 45 rotates. In this case, the pin holding part 165 can be directly or indirectly connected to the nut 41. Power can also be transmitted from the motor 21 to the ball screw mechanism 40 through a gear set different from the example of the above embodiment.

[0118] The control circuit of the controller 20 may be composed of programmable logic devices such as ASIC (Application Specific Integrated Circuit) and FPGA (Field Programmable Gate Array) instead of a microcomputer.

[0119] Furthermore, in view of the spirit of the above embodiments and their modifications, the present invention can be constructed in the following ways. At least one of the following ways can be combined with at least one of the structures (features) described in the above embodiments and their modifications, as well as the technical solutions.

[0120] [Method 1]

[0121] The first magnetic sensor and the second magnetic sensor are configured to detect magnetic field components in directions orthogonal to the detection surface, respectively.

[0122] [Method 2]

[0123] The first magnetic sensor and the second magnetic sensor are Hall sensors configured to detect the magnetic field of the magnet using the Hall effect.

[0124] [Method 3]

[0125] The control device is configured to control the movement of the pin holding part by controlling the drive of the motor.

[0126] [Method 4]

[0127] One of the first detection surface and the second detection surface is configured to face the second axis.

[0128] The other of the first detection surface and the second detection surface is configured to face a direction away from the second axis.

[0129] [Method 5]

[0130] One of the first detection direction and the second detection direction is a direction away from the second axis.

[0131] The other of the first detection direction and the second detection direction is the direction toward the second axis.

Claims

1. A fastening tool configured to fasten a workpiece using a fastener comprising a pin and a cylindrical portion, characterized in that, It includes a motor, an anvil, a pin holding part, a magnet, a first magnetic sensor, a second magnetic sensor, and a control device, wherein, The anvil can abut against the cylindrical portion; The pin holding part is configured to hold the pin and is configured to move relative to the anvil along a first axis by the power of the motor, wherein the first axis defines the front-rear direction of the fastening tool; The magnet is arranged with its N pole and S pole arranged in the front-back direction, and is configured to move integrally with the pin holding part along a second axis parallel to the first axis in the front-back direction; The first magnetic sensor has a first detection surface; The second magnetic sensor has a second detection surface, and the second magnetic sensor is positioned further back than the first magnetic sensor; The control device is configured to, based on the detection result of the second magnetic sensor, move the pin holding portion rearward relative to the anvil from an initial position to a stop position, and based on the detection result of the first magnetic sensor, move the pin holding portion forward relative to the anvil from the stop position to the initial position. The first magnetic sensor and the second magnetic sensor are configured as unipolar detection type sensors to detect the same predetermined magnetic pole of the magnet. The first magnetic sensor and the second magnetic sensor are configured such that the orientation of the first detection surface relative to the second axis is opposite to the orientation of the second detection surface relative to the second axis.

2. The fastening tool according to claim 1, characterized in that, The specified magnetic pole is the one of the N pole and the S pole that is positioned on the rear side. The first detection surface is configured to face the second axis. The second detection surface is configured to face away from the second axis.

3. The fastening tool according to claim 2, characterized in that, The specified magnetic pole is the N pole.

4. The fastening tool according to any one of claims 1 to 3, characterized in that, The first magnetic sensor and the second magnetic sensor are configured on the same side relative to an imaginary plane containing the second axis.

5. The fastening tool according to any one of claims 1 to 3, characterized in that, The distance between the magnet and the detection point of the first magnetic sensor when the magnet and the first magnetic sensor are located on a first straight line orthogonal to the second axis is equal to the distance between the magnet and the detection point of the second magnetic sensor when the magnet and the second magnetic sensor are located on a second straight line orthogonal to the second axis.

6. The fastening tool according to any one of claims 1 to 3, characterized in that, The first magnetic sensor and the second magnetic sensor are respectively mounted on a separately disposed first substrate and a second substrate.

7. The fastening tool according to any one of claims 1 to 3, characterized in that, The first magnetic sensor and the second magnetic sensor are sensors with the same structure.

8. The fastening tool according to any one of claims 1 to 3, characterized in that, The fastening tool can use a fracture fastener as the fastener, in which a pin having a small diameter portion for fracture is inserted into the cylindrical portion. The pin holding portion is configured to pull the pin backward relative to the cylindrical portion to secure the workpiece during the movement from the initial position to the stop position, and to cause the pin to break at the small diameter portion.

9. A fastening tool configured to fasten a workpiece using a fastener comprising a pin and a cylindrical portion, characterized in that, It includes a motor, an anvil, a pin holding part, a magnet, a first magnetic sensor, a second magnetic sensor, and a control device, wherein, The anvil can abut against the cylindrical portion; The pin holding part is configured to hold the pin and is configured to move relative to the anvil along a first axis by the power of the motor, wherein the first axis defines the front-rear direction of the fastening tool; The magnet is arranged with its N pole and S pole aligned in the front-rear direction, and is configured to move integrally with the pin holding portion along a second axis parallel to the first axis in the front-rear direction; The first magnetic sensor defines the first detection direction; The second magnetic sensor defines a second detection direction, and the second magnetic sensor is positioned further back than the first magnetic sensor; The control device is configured to, based on the detection result of the second magnetic sensor, move the pin holding portion rearward relative to the anvil from an initial position to a stop position, and based on the detection result of the first magnetic sensor, move the pin holding portion forward relative to the anvil from the stop position to the initial position. The first magnetic sensor and the second magnetic sensor are unipolar detection type sensors configured to detect the same predetermined magnetic pole of the magnet, respectively. The first magnetic sensor and the second magnetic sensor are configured such that the orientation of the first detection direction relative to the second axis is opposite to the orientation of the second detection direction relative to the second axis.

10. The fastening tool according to claim 9, characterized in that, The specified magnetic pole is the one of the N pole and the S pole that is positioned on the rear side. The first detection direction is the direction away from the second axis. The second detection direction is the direction toward the second axis.

11. The fastening tool according to claim 10, characterized in that, The specified magnetic pole is the N pole.

12. The fastening tool according to any one of claims 9 to 11, characterized in that, The first magnetic sensor and the second magnetic sensor are configured on the same side relative to an imaginary plane containing the second axis.

13. The fastening tool according to any one of claims 9 to 11, characterized in that, The distance between the magnet and the detection point of the first magnetic sensor when the magnet and the first magnetic sensor are located on a first straight line orthogonal to the second axis is equal to the distance between the magnet and the detection point of the second magnetic sensor when the magnet and the second magnetic sensor are located on a second straight line orthogonal to the second axis.

14. The fastening tool according to any one of claims 9 to 11, characterized in that, The first magnetic sensor and the second magnetic sensor are respectively mounted on a separately disposed first substrate and a second substrate.

15. The fastening tool according to any one of claims 9 to 11, characterized in that, The first magnetic sensor and the second magnetic sensor are sensors with the same structure.

16. The fastening tool according to any one of claims 9 to 11, characterized in that, The fastening tool can use a fracture fastener as the fastener, in which a pin having a small diameter portion for fracture is inserted into the cylindrical portion. The pin holding portion is configured to pull the pin backward relative to the cylindrical portion to secure the workpiece during the movement from the initial position to the stop position, and to cause the pin to break at the small diameter portion.

Images